Ferroptosis and autophagy are closely associated with Alzheimer's disease (AD). Elevated ferric ion levels can induce oxidative stress and chronic inflammatory responses, resulting in brain tissue damage and further neurological cell damage. Autophagy in Alzheimer's has a dual role. On one hand, it protects neurons by removing β-amyloid and cellular damage products caused by oxidative stress and inflammation. On the other hand, abnormal autophagy is linked to neuronal apoptosis and neurodegeneration. However, the intricate interplay between ferroptosis and autophagy in AD remains insufficiently explored. This study focuses on the roles of ferroptosis and autophagy in AD and their interconnection through bioinformatics analysis, shedding light on the disease. Ferroptosis and autophagy significantly correlate with the development and course of AD. Using PPI network analysis and unsupervised consistency clustering analysis, we uncovered a complex network of interactions between ferroptosis and autophagy during disease progression, demonstrating a significant congruence in their modification patterns. Functional analyses further demonstrated that ferroptosis and autophagy together affect the immunological status and synaptic regulation in hippocampal regions in patients with AD, which significantly impacts the start and progression of the disease.

The paradoxical exacerbation of cellular injury and death during reperfusion remains a problem in the treatment of myocardial infarction. Mitochondrial dysfunction plays a key role in the pathogenesis of myocardial ischemia and reperfusion injury. Dysfunctional mitochondria can be removed by mitophagy, culminating in their degradation within acidic lysosomes. Mitophagy is pivotal in maintaining cardiac homeostasis and emerges as a potential therapeutic target. Here, we employed beating human engineered heart tissue (EHT) to assess mitochondrial dysfunction and mitophagy during ischemia and reperfusion simulation. Our data indicate adverse ultrastructural changes in mitochondrial morphology and impairment of mitochondrial respiration. Furthermore, our pH-sensitive mitophagy reporter EHTs, generated by a CRISPR/Cas9 endogenous knock-in strategy, revealed induced mitophagy flux in EHTs after ischemia and reperfusion simulation. The induced flux required the activity of the protein kinase ULK1, a member of the core autophagy machinery. Our results demonstrate the applicability of the reporter EHTs for mitophagy assessment in a clinically relevant setting. Deciphering mitophagy in the human heart will facilitate development of novel therapeutic strategies.

Ischemia-reperfusion (I/R) injury describes the pathological process wherein tissue damage, initially caused by insufficient blood supply (ischemia), is exacerbated upon the restoration of blood flow (reperfusion). This phenomenon can lead to irreversible tissue damage and is commonly observed in contexts such as cardiac surgery and stroke, where blood supply is temporarily obstructed. During ischemic conditions, the anaerobic metabolism of tissues and organs results in compromised enzyme activity. Subsequent reperfusion exacerbates mitochondrial dysfunction, leading to increased oxidative stress and the accumulation of reactive oxygen species (ROS). This cascade ultimately triggers cell death through mechanisms such as autophagy and mitophagy. Autophagy constitutes a crucial catabolic mechanism within eukaryotic cells, facilitating the degradation and recycling of damaged, aged, or superfluous organelles and proteins via the lysosomal pathway. This process is essential for maintaining cellular homeostasis and adapting to diverse stress conditions. As a cellular self-degradation and clearance mechanism, autophagy exhibits a dualistic function: it can confer protection during the initial phases of cellular injury, yet potentially exacerbate damage in the later stages. This paper aims to elucidate the fundamental mechanisms of autophagy in I/R injury, highlighting its dual role in regulation and its effects on both organ-specific and systemic responses. By comprehending the dual mechanisms of autophagy and their implications for organ function, this study seeks to explore the potential for therapeutic interventions through the modulation of autophagy within clinical settings.

Mitochondria play a critical role in oxidative stress (OS)-induced neuronal injury during ischemic stroke (IS), making them promising therapeutic targets. Mounting evidence underscores the extraordinary therapeutic promise of exosomes derived from human neural stem cells (hNSCs) in the management of central nervous system (CNS) diseases. Nonetheless, the precise mechanisms by which these exosomes target mitochondria to ameliorate the effects of IS remain only partially elucidated. This study investigates the protective effects of hNSC derived exosomes (hNSC-Exos) on neuronal damage.

Using a rat model of middle cerebral artery occlusion (MCAO) in vivo and OS-induced HT22 cells in vitro. Firstly, our research group independently isolated human neural stem cells (hNSCs) and subsequently prepared hNSC-Exos. In vivo, MCAO rats were restored to blood flow perfusion to simulate ischemia-reperfusion injury, and hNSC-Exos were injected through stereotaxic injection into the brain. Subsequently, the protective effects of hNSC-Exos on MCAO rats were evaluated, including histological studies, behavioral assessments. In vivo, H2O2 was used in HT22 cells to simulate the OS environment in MCAO, and then its protective effects on HT22 were evaluated by co-culturing with hNSC-Exos, including immunofluorescence staining, western blotting (WB), quantitative real time PCR (qRT-PCR). In the process of exploring specific mechanisms, we utilized RNA sequencing (RNA-seq) to detect the potential induction of mitophagy in OS-induced HT22 cells. Afterwards, we employed a series of mitochondrial function assessments and autophagy related detection techniques, including measuring mitochondrial membrane potential, reactive oxygen species (ROS) levels, transmission electron microscopy (TEM) imaging, monodansylcadaverine (MDC) staining, and mCherry-GFP-LC3B staining. In addition, we further investigated the regulatory pathway of hNSC-Exos by using autophagy inhibitor mdivi-1 and knocking out PTEN induced kinase 1 (PINK1) in HT22 cells.

Administration of hNSC-Exos significantly ameliorated brain tissue damage and enhanced behavioral outcomes in MCAO rats. This treatment led to a reduction in brain tissue apoptosis and facilitated the normalization of impaired neurogenesis and neuroplasticity. Notably, the application of hNSC-Exos in vitro resulted in an upregulation of mitophagy in HT22 cells, thereby remedying mitochondrial dysfunction. We demonstrate that hNSC-Exos activate mitophagy via the PINK1/Parkin pathway, improving mitochondrial function and reducing neuronal apoptosis.

These findings suggest that hNSC-Exos alleviate OS-induced neuronal damage by regulating the PINK1/Parkin pathway. These reveals a novel role of stem cell-derived mitochondrial therapy in promoting neuroprotection and suggest their potential as a therapeutic approach for OS-associated CNS diseases, including IS.

To date, no therapeutic drugs available on the market can effectively reverse the progression of Alzheimer's disease (AD). Although Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) and Cholecystokinin (CCK) RAs have shown some promise in AD research, little is known about the neuroprotective effects of a novel dual CCK/GLP-1 RA in AD. This study sought to examine the effects of the novel dual CCK/GLP-1 RA on cognitive performance in an AD mouse model and to explore the associated mechanisms. Our findings indicate that dual CCK/GLP-1 RA improved cognitive deficits, reduced amyloid-beta (Aβ) accumulation, and alleviated mitochondrial damage in 5 × FAD mice by inducing mitophagy. In an in vitro model of AD cells induced by Aβ, CCK/GLP-1 RA could exert neuroprotective effects by regulating PINK1/Parkin-mediated mitophagy. These data reveal for the first time that the new CCK/GLP-1 RA modulates mitophagy via PINK1/Parkin pathway and enhances cognitive function in the 5 × FAD animal model. Moreover, the performance of the CCK/GLP-1 RA in certain indicators was superior to that of GLP-1 analogue liraglutide, suggesting that it may represent a more promising therapeutic option for AD.

The pKa values of mitochondrial fluorescent probes based on pH response differ significantly from the pH of the mitochondrial matrix, making the development of mitochondria-targeted pH probes with appropriate pKa values essential for accurately monitoring mitochondrial pH fluctuations. In this paper, three mitochondria-targeted near-infrared fluorescent probes 5a-5c were successfully developed by introducing nitrogen atom at the 4-position of Nile Blue and modulating the pKa through the formation of intramolecular hydrogen bonding. Probes 5a-5c exhibited ultra-high molar extinction coefficients up to 105 M-1 cm-1, along with excellent photostability and sensitive pH response properties. The fluorescence intensities of 5a-5c enhanced 12-14-fold, while the fluorescence quantum yields increased from 1.2 %-2.5 % to 13 %-16 % with the pH decreasing from 10 to 4.0 (including only 0.5 % cosolvent). In addition, linear relationships between pH and maximum fluorescence intensity were established with high correlation coefficient (R2 = 0.99) from pH 5.2 to 9.2. Based on the low toxicity and mitochondrial targeting ability, probes 5a-5c migrated from mitochondria to lysosomes during starvation and rapamycin-induced autophagy, allowing real-time tracking of mitochondrial pH variations using fluorescence intensity and colocalization coefficient as parameters. Notably, dynamic changes between mitochondria and lysosomes were observed in real time in the mitochondrial damage model constructed by hydrogen peroxide. In conclusion, probes 5a-5c have excellent optical properties and biocompatibility, underscoring their significance in monitoring mitochondrial physiological and pathological processes.

Sevoflurane exposure induces cognitive deficits in neonatal mice. Mitophagy was closely correlated to sevoflurane inhalation induced neurotoxicity in developing brains. However, the underlying mechanisms have not been fully elucidated. In this study, we attempted to clarify the role of mitophagy in neonatal mice undergoing sevoflurane exposure. BV2 microglial cells were cultured, and mcherry-EGFP-LC3B adenovirus were transfected. The results showed that the fluorescence intensity of GFP was markedly increased after sevoflurane exposure, and rapamycin administration could mitigate this effect. The mitophagy flux test showed that sevoflurane exposure reduced the degree of colocalization between Mito-Traker and Lyso-Traker fluorescent, while which was elevated by rapamycin treatment. The immunofluorescence assay suggested that sevoflurane inhalation resulted in the significant decrease of autolysosome formation, which was sharply enhanced in SEV group after rapamycin treatment. Meanwhile, sevoflurane inhalation shifted microglial M1/M2 phenotypic polarization, and rapamycin administration reversed this status. Moreover, the degree of colocalization among Iba-1, Synaptophysin (Syn) and lysosomal-associated membrane protein 1 (Lamp1) was increased after sevoflurane exposure, and that was reduced following rapamycin treatment. The behavioral performance was worse after sevoflurane inhalation in neonatal mice, and rapamycin treatment effectively improved the cognitive outcome. Collectively, these findings demonstrated that mitophagy impairment induced by sevoflurane exposure promoted microglia M1 phenotypic polarization and enlarged phagocytosis, and resulted in cognitive deficits, while rapamycin administration effectively reversed this tendency.

Parkinson's disease (PD) has emerged as a multisystem disorder affecting multiple cellular and organellar systems in addition to the dopaminergic neurons. Disease-specific induced pluripotent stem cells (iPSCs) model early developmental changes and cellular perturbations that are otherwise inaccessible from clinical settings. Here, we report the early changes in patient-derived iPSCs carrying a homozygous recessive mutation, R741Q, in the PLA2G6 gene. A gene-edited R747W iPSC line mirrored these phenotypes, thus validating our initial findings. Bioenergetic dysfunction and hyperpolarization of mitochondrial membrane potentials were hallmarks of the PD iPSCs. Further, a concomitant increase in glycolytic activity indicated a possible compensation for mitochondrial respiration. Elevated basal reactive oxygen species (ROS) and decreased catalase expression were also observed in the disease iPSCs. No change in autophagy was detected. These inceptive changes could be potential targets for early intervention of prodromal PD in the absence of disease-modifying therapies. However, additional investigations are crucial to delineate the cause-effect relationships of these observations.

Mitophagy is a selective way to eliminate dysfunctional mitochondria and recycle their constituents, which plays an important role in regulating and maintaining intracellular homeostasis. Real-time monitoring mitophagy process is of great importance for cellular physiological and pathological processes related to mitochondria. Howbeit, most of the current methods only focus on single-parameter detection of mitochondrial microenvironmental changes such as pH, viscosity and polarity. The mitochondrial molecular responses under mitophagy are not clear. Therefore, developing a new and simple method for molecular profiling is of great importance for accurately and comprehensively visualizing mitophagy.

In this work, Au NPs-based mitochondria-targeting nanoprobe was developed and the nanoprobe-based label-free surface enhanced Raman spectroscopy (SERS) method was proposed to track starvation induced mitophagy process at molecular level. The nanoprobe displayed good SERS performance and low cytotoxicity. Based on the developed strategy, the molecular response within mitochondria under mitophagy was validated. Meanwhile, the protein denaturation, conformational change, lipid degradation and DNA fragmentation within mitochondria under mitophagy were revealed for the first time, which provides molecular evidence for mitophagy. The changes in reactive oxygen species level and mitochondrial membrane potential further confirmed the damage of mitochondria. Moreover, the developed label-free SERS strategy was used to detect mitophagy in drug (cisplatin)-induced liver injury (DILI) cell model, and obvious mitophagy in DILI cells was observed.

The molecular biochemical signature dynamic changes within mitochondria during mitophagy process were revealed by SERS for the first time. Moreover, compared with the current research, our study can provide new insights into mitophagy and mitophagy-involved diseases at molecular level. This study will provide new insights into the molecular mechanism of mitophagy and offer a simple and effective method for mitochondrial molecular event monitoring in mitophagy-involved cellular processes.

Globally, esophageal cancer stands as a prominent contributor to cancer-related fatalities, distinguished by its poor prognosis. Mitophagy has a significant impact on the process of cancer progression. This study investigated the prognostic significance of mitophagy-related genes (MRGs) in esophageal carcinoma (ESCA) to elucidate molecular subtypes. By analyzing RNA-seq data from The Cancer Genome Atlas (TCGA), 6451 differentially expressed genes (DEGs) were identified. Cox regression analysis narrowed this list to 14 MRGs with potential prognostic implications. ESCA patients were classified into two distinct subtypes (C1 and C2) based on these genes. Furthermore, leveraging the differentially expressed genes between Cluster 1 and Cluster 2, ESCA patients were classified into two novel subtypes (CA and CB). Importantly, patients in C2 and CA subtypes exhibited inferior prognosis compared to those in C1 and CB (p < 0.05). Functional enrichments and immune microenvironments varied significantly among these subtypes, with C1 and CB demonstrating higher immune checkpoint expression levels. Employing machine learning algorithms like LASSO regression, Random Forest and XGBoost, alongside multivariate COX regression analysis, two core genes: HSPD1 and MAP1LC3B were identified. A prognostic model based on these genes was developed and validated in two external cohorts. Additionally, single-cell sequencing analysis provided novel insights into esophageal cancer microenvironment heterogeneity. Through Coremine database screening, Icaritin emerged as a potential therapeutic candidate to potentially improve esophageal cancer prognosis. Molecular docking results indicated favorable binding efficacies of Icaritin with HSPD1 and MAP1LC3B, contributing to the understanding of the underlying molecular mechanisms of esophageal cancer and offering therapeutic avenues.

Multiple lines of evidence indicate that mitochondrial dysfunction occurs in demyelinating diseases, such as multiple sclerosis (MS). Failure of remyelination is thought to be caused in part by a block of oligodendrocyte progenitor cell (OPC) differentiation into oligodendrocytes, which generate myelin sheaths around axons. The process of OPC differentiation requires a substantial amount of energy and high demand for ATP which is supplied through the mitochondria. In this study, we highlight mitochondrial gene expression changes during OPC differentiation in two murine models of remyelination and in human postmortem MS brains. Given these transcriptional alterations, we then investigate whether genetic alteration of USP30, a mitochondrial deubiquitinase, enhances OPC differentiation and myelination. By genetic knockout of USP30, we observe increased OPC differentiation and myelination without affecting OPC proliferation and survival in in vitro and ex vivo assays. We also find that OPC differentiation is accelerated in vivo following focal demyelination in USP30 knockout mice. The promotion of OPC differentiation and myelination observed is associated with increased oxygen consumption rates in USP30 knockout OPCs. Together, these data indicate a role for mitochondrial function and USP30 in OPC differentiation and myelination.

Endometriosis affects about 10 % of women of reproductive age, leading to a disabling gynecologic condition. Chronic pain, inflammation, and oxidative stress have been identified as the molecular pathways involved in the progression of this disease, although its precise etiology remains uncertain. Although mitochondria are considered crucial organelles for cellular activity, their dysfunction has been linked to the development of this disease. The purpose of this review is to examine the functioning of the mitochondrion in endometriosis: in particular, we focused on the mitochondrial dynamics of biogenesis, fusion, and fission. Since excessive mitochondrial activity is reported to affect cell proliferation, we also considered mitophagy as a mechanism involved in limiting disease development. To better understand mitochondrial activity, we also considered alterations in circadian rhythms, the gut microbiome, and estrogen receptors: indeed, these mechanisms are also involved in the development of endometriosis. In addition, we focused on recent research about the impact of numerous substances on mitochondrial activity; some of them may offer a future breakthrough in endometriosis treatment by acting on mitochondria and inhibiting cell proliferation.

Cellular stress response is the response of the cell at molecular level in order to combat various environmental stressors / viral infections. These stressors can be either intra or extracellular. In the beginning of the insult cell tries to recoup from these adverse events by various mechanism like heat shock protein response, unfolded protein response, mitochondrial stress signaling, DNA damage response etc. However, if these stressors exceed the cellular capacity to coup with it, it leads to programmed cell death and senescence. Also, chronic stress and cortisol released in response to cellular stress decreases telomerase activity which is needed to replenish telomeres which are protective casing at the end of a strand of DNA. Too low telomeres lead to cell death or cell become pro-inflammatory leading to aging process and other health associated risks like cardiovascular diseases neurodegenerative diseases, autoimmune diseases, cancers etc.

Hyperoxia therapy is a critical clinical intervention for both acute and chronic illnesses. However, prolonged exposure to high-concentration oxygen can cause lung injury. The mechanisms of hyperoxic lung injury (HLI) remain incompletely understood, and current treatment options are limited. Improving the safety of hyperoxia therapy has thus become an urgent priority. Ferroptosis, a novel form of regulated cell death characterized by iron accumulation and excessive lipid peroxidation, has been implicated in the pathogenesis of HLI, including diffuse alveolar damage, vascular endothelial injury, and bronchopulmonary dysplasia. In this review, we analyze the latest findings on ferroptosis and therapeutic strategies for HLI. Our aim is to provide new insights for the treatment of HLI and to facilitate the translation of these findings from bench to bedside.

Pemphigus is an autoimmune blistering disease where autoantibodies target desmoglein (Dsg) antigens on keratinocytes, triggering the p38 MAPK pathway, Dsg internalization, desmosomal dissolution, and keratinocyte apoptosis, are essential for blister formation. Recent research indicates keratinocyte pyroptosis may exacerbate acantholysis and delay wound healing. Current treatments, including corticosteroids and immunosuppressants, are effective but have significant side effects, such as prolonged wound healing and increased infection risk. Understanding these inflammatory processes is crucial for developing effective treatments for pemphigus.

The authors conducted a comprehensive review of the literature, analyzing recent findings regarding the upregulation of pyroptosis-related proteins in pemphigus.

The present findings highlight a significant upregulation of pyroptosis-related proteins, which play a crucial role in the inflammatory response and blister formation characteristic of pemphigus. Key proteins such as cytokines IL-1β, IL-18, High Mobility Group Box-1 (HMGB1), and Parkin, along with NOD-like receptors and P2×7 receptors, were identified as pivotal in facilitating pyroptosis. The study also discusses potential therapeutic approaches targeting these proteins to modulate the disease pathway effectively.

This study aimed to investigate the role of pyroptosis in the pathogenesis of pemphigus, focusing on its potential as a novel therapeutic target.

Pyroptosis significantly contributes to the pathogenesis of pemphigus and presents a promising target for therapy. Targeting specific molecules involved in the pyroptosis pathway offers the potential for developing more precise and less toxic treatments, allowing the shift from traditional therapies towards targeted therapeutic strategies.

The mechanisms of adipose tissue activation and inactivation have been a hot topic of research in the last decade, from which countermeasures have been attempted to be found against obesity as well as other lipid metabolism-related diseases, such as type 2 diabetes mellitus and non-alcoholic fatty liver disease. Autophagy has been shown to be closely related to the regulation of adipocyte activity, which is involved in the whole process including white adipocyte differentiation/maturation and brown or beige adipocyte generation/activation. Dysregulation of autophagy in adipose tissue has been demonstrated to be associated with obesity. On this basis, we summarize the pathways and mechanisms of autophagy involved in the regulation of lipid metabolism and present a review of its pathophysiological roles in lipid metabolism-related diseases, in the hope of providing ideas for the treatment of these diseases.

Stroke remains a leading cause of disability and mortality worldwide, with mitochondrial dysfunction closely linked to ischemic injury. This study explores the Norad-Pum2-Mff axis as a key regulator of mitochondrial function following ischemia-reperfusion (I/R) injury. Using an oxygen-glucose deprivation/reoxygenation (OGD/R) model, Mff protein levels were significantly elevated post-OGD/R, while mRNA levels remained unchanged, suggesting post-transcriptional regulation. Pumilio2 (Pum2), an RNA-binding protein, was shown to inhibit Mff translation, while Norad, a long non-coding RNA, sequestered Pum2, alleviating this inhibition. We observed decreased Pum2 levels and binding capacity to Mff mRNA, alongside increased Norad levels and binding to Pum2 in neurons after OGD/R. Overexpression of Pum2 in neurons reduced Mff levels, mitigated mitochondrial fragmentation, and alleviated neuronal injury. In a mouse model of middle cerebral artery occlusion/reperfusion (MCAO/R), Pum2 overexpression further improved mitochondrial morphology, reduced infarct volume, and enhanced neurobehavioral recovery. These findings suggest that targeting the Norad-Pum2-Mff axis could provide a promising therapeutic strategy for ischemic stroke by restoring mitochondrial function and reducing neuronal damage.

Stathmin 1 is a cytoplasmic phosphoprotein that regulates microtubule dynamics via promotion of microtubule catastrophe and sequestration of free tubulin heterodimers. Stathmin 1 is highly expressed in hematopoietic stem cells (HSCs), and overexpressed in leukemic cells, however its role in HSCs is not known. Herein, we found that loss of Stathmin 1 is associated with altered microtubule architecture in HSCs, and markedly impaired HSC function. Transcriptomic studies suggested alterations in oxidative phosphorylation in Stmn1 -/- HSCs, and further mechanistic studies revealed defective mitochondrial structure and function in the absence of Stathmin 1 with increased ROS production. Microtubules associate with mitochondria and lysosomes to facilitate autophagosome formation and mitophagy, and indeed we found that this critical mitochondrial quality control process is impaired in Stathmin 1-deficient HSCs. Finally, stimulation of autophagy improved the colony forming ability of Stmn1 -/- hematopoietic stem and progenitor cells. Together, our data identify Stathmin 1 as a novel regulator of mitophagy and mitochondrial health in HSCs.

The microtubule regulating protein Stathmin 1 is highly expressed in HSPCs and promotes normal microtubule architecture.Loss of Stathmin 1 in HSPCs leads to impaired autophagy with abnormal mitochondrial morphology, decreased respiratory capacity, and impaired cellular function.

PTEN-induced kinase-1 (PINK1) is a crucial player in selective clearance of damaged mitochondria via the autophagy-lysosome pathway, a process termed mitophagy. Previous studies on PINK1 mainly focused on its post-translational modifications, while the transcriptional regulation of PINK1 is much less understood. Herein, we reported a novel mechanism in control of PINK1 transcription by SMAD Family Member 3 (SMAD3), an essential component of the transforming growth factor beta (TGFβ)-SMAD signaling pathway. First, we observed that mitochondrial depolarization promotes PINK1 transcription, and SMAD3 is likely to be the nuclear transcription factor mediating PINK1 transcription. Intriguingly, SMAD3 positively transactivates PINK1 transcription independent of the canonical TGFβ signaling components, such as TGFβ-R1, SMAD2 or SMAD4. Second, we found that mitochondrial depolarization activates SMAD3 via PINK1-mediated phosphorylation of SMAD3 at serine 423/425. Therefore, PINK1 and SMAD3 constitute a positive feedforward loop in control of mitophagy. Finally, activation of PINK1 transcription by SMAD3 provides an important pro-survival signal, as depletion of SMAD3 sensitizes cells to cell death caused by mitochondrial stress. In summary, our findings identify a non-canonical function of SMAD3 as a nuclear transcriptional factor in regulation of PINK1 transcription and mitophagy and a positive feedback loop via PINK1-mediated SMAD3 phosphorylation and activation. Understanding this novel regulatory mechanism provides a deeper insight into the pathological function of PINK1 in the pathogenesis of neurodegenerative diseases such as Parkinson's disease.

Akt3 is a key regulator of mitochondrial homeostasis in the endothelium. Akt3 depletion results in mitochondrial dysfunction, decreased mitochondrial biogenesis, and decreased angiogenesis. Here we link mitochondrial homeostasis with mitotic fidelity-depletion of Akt3 results in the missegregation of chromosomes as visualized by multinucleation and micronuclei formation. We have connected Akt3 to Aurora B, a significant player in chromosome segregation. Akt3 localizes to the nucleus, where it associates with and regulates WDR12. During mitosis, WDR12 is localized to the dividing chromosomes, and its depletion results in a similar mitotic phenotype to Akt3 depletion. WDR12 associates with Aurora B, both of which are downregulated under conditions of Akt3 depletion. We used the model oxidant paraquat to induce mitochondrial dysfunction to test whether the Akt3-dependent effect on mitochondrial homeostasis is linked to mitotic function. Paraquat treatment also causes chromosome missegregation by inhibiting the expression of Akt3, WDR12, and Aurora B. The inhibition of ROS rescued both the mitotic fidelity and the expression of Akt3 and Aurora B. Akt3 directly phosphorylates the major nuclear export protein CRM-1, causing an increase in its expression, resulting in the inhibition of PGC-1 nuclear localization, the master regulator of mitochondrial biogenesis. The Akt3/Aurora B pathway is also dependent on CRM-1. CRM-1 overexpression resulted in chromosome missegregation and downregulation of Aurora B similar to that of Akt3 depletion. Akt3 null hearts at midgestation (E14.5), a stage in which proliferation is occurring, have decreased Aurora B expression, increased CRM-1 expression, decreased proliferation, and increased apoptosis. Akt3 null hearts are smaller and have a thinner compact cell layer than age-matched wild-type mice. Akt3 null tissue has dysmorphic nuclear structures, suggesting mitotic catastrophe. Our findings show that mitochondrial dysfunction induced by paraquat or Akt3 depletion results in a CRM-1-dependent disruption of Aurora B and mitotic fidelity.

Phosphatase and tensin homolog-induced putative kinase 1 (PINK1) and parkin RBR E3 ubiquitin protein ligase (Parkin) emerged as mediators of mitophagy and regulators of the immune response in mammals. However, their gene characterizations and roles remain poorly understood in fish. Herein, we identified and characterized pink1 and parkin genes and studied their involvement in immune responses to lipopolysaccharide (LPS) in Ctenopharyngodon idellus kidney (CIK) cells. Bioinformatic analysis found that PINK1 and Parkin were relatively conservative during evolution. In CIK cells, LPS significantly increased the mRNA expression of the transcription factor nf-κb and its downstream proinflammatory cytokines, such as tnfα, il-6 and il-1β, along with the activation of PINK1/Parkin-mediated mitophagy (P < 0.05). Furthermore, inhibition of mitophagy aggravated LPS-induced inflammation in CIK cells. Overall, our findings suggest that PINK1/Parkin-mediated mitophagy may play a protective role in LPS-induced inflammation in fish.

The gut-brain axis plays a crucial role in the regulation and development of psychological and physical processes. The first year of life is a critical period for the development of the gut microbiome, which parallels important milestones in establishing sleep rhythm and brain development. Growing evidence suggests that the gut microbiome influences sleep, cognition and early neurodevelopment. For term-born and preterm-born infants, difficulties in sleep regulation may have consequences on health. Identifying effective interventions on the gut-brain axis in early life is likely to have long-term implications for the health and development of at-risk infants.

In this multicentre, four-group, double-blinded, placebo (PLC)-controlled randomised trial with a factorial design, 120 preterm-born and 260 term-born infants will be included. The study will investigate whether the administration of daily synbiotics or PLC for a duration of 3 months improves sleep patterns and neurodevelopmental outcomes up to 2 years of age. The trial will also: (1) determine the association between gut microbiota, sleep patterns and health outcomes in children up to 2 years of age; and (2) leverage the interactions between gut microbiota, brain and sleep to develop new intervention strategies for at-risk infants.

The NapBiome trial has received ethical approval by the Committee of Northwestern and Central Switzerland and Canton Vaud, Switzerland (#2024-01681). Outcomes will be disseminated through publication and will be presented at scientific conferences. Metagenomic data will be shared through the European Nucleotide Archive.

The US National Institutes of Health NCT06396689.

Bisphenol AF (BPAF) has been widely used as a main alternative to bisphenol A (BPA), and previous in vitro studies have shown that BPAF has higher reproductive toxicity potentials than BPA. However, data on in vivo toxicity of BPAF is still limited. In this study, Sprague Dawley rats were exposed to BPAF (0, 50, and 100 mg/kg/day) during gestation to study toxicokinetics and reproductive toxicity in offspring. The results showed that plasma concentrations BPAF peaked within 6 h after birth, followed by a two-phase decay, with clearance rates of approximately 3.0 l/h and terminal half-life values ranging from 77 h to 114 h, suggesting fast absorption and high persistence of BPAF. At postnatal day 21 (PND21), BPAF was found to be bioaccumulated in reproductive organs (testes and ovaries) of the offspring, resulting in adverse effects on reproduction in both sexes. Lower anogenital distance, reduced relative testicular weight, dissolved interstitial cells, fewer primary spermatocytes, decreased testosterone levels, and increased luteinizing hormone levels were detected in male offspring. In female offspring, vacuolization in follicular antrum, fewer follicles, increased 17β-estradiol levels, and increased luteinizing hormone levels in female offspring were found. Gene expression of scavenger receptor class B type I (SR-B1), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), sterol regulatory element-binding protein-1c (SREBP-1c), and several steroidogenic enzymes was significantly decreased in male offspring following maternal exposure to BPAF, suggesting that the decreases in testosterone levels is a result of inhibited cholesterol uptake, cholesterol de novo synthesis, and steroidogenesis. In addition, inhibition of pathways of phagosome and cell adhesion molecules might be the underlying molecular mechanism involved in BPAF-induced reproductive disorders in male offspring. This study provides the scientific basis for a comprehensive assessment of the safety of BPAF.

Contactin-associated protein1 (Caspr1) plays an important role in the formation and stability of myelinated axons. In Caspr1 mutant mice, autophagy-related structures accumulate in neurons, causing axonal degeneration; however, the mechanism by which Caspr1 regulates autophagy remains unknown. To illustrate the mechanism of Caspr1 in autophagy process, we demonstrated that Caspr1 knockout in primary neurons from mice along with human cell lines, HEK-293 and HeLa, induced autophagy by downregulating the PI3K/AKT/mTOR signaling pathway to promote the conversion of microtubule-associated protein light chain 3 I (LC3-I) to LC3-II. In contrast, Caspr1 overexpression in cells contributed to the upregulation of this signaling pathway. We also demonstrated that Caspr1 knockout led to increased LC3-I protein expression in mice. In addition, Caspr1 could inhibit the expression of autophagy-related 4B cysteine peptidase (ATG4B) protein by directly binding to ATG4B in overexpressed Caspr1 cells. Intriguingly, we found an accumulation of ATG4B in the Golgi apparatuses of cells overexpressing Caspr1; therefore, we speculate that Caspr1 may restrict ATG4 secretion from the Golgi apparatus to the cytoplasm. Collectively, our results indicate that Caspr1 may regulate autophagy by modulating the PI3K/AKT/mTOR signaling pathway and the levels of ATG4 protein, both in vitro and in vivo. Thus, Caspr1 can be a potential therapeutic target in axonal damage and demyelinating diseases.

Early treatment of mandibular advancement device (MAD) reverses the abnormal changes resulting from obstructive sleep apnoea (OSA), but the underlying mechanism is not clear. We analysed the changes of genioglossus function before and after MAD treatment in OSA rabbits and explored the mechanism of mitochondrial autophagy.

Eighteen male New Zealand rabbits were randomised into three groups: the control group, Group OSA, and Group MAD. After successful modelling, all animals were induced sleep in supine positions for 4-6 h per day for 8 weeks. Cone beam computed tomography (CBCT) and polysomnography (PSG) were performed to record sleep conditions. The genioglossus contractile force and the levels of LC3-I, LC3-II, Beclin-1, PINK1 and Parkin were detected in three groups. In vitro, C2C12 myoblast cells were cultured under normoxic or hypoxic conditions for 24 h, and then the changes in mitochondrial structure and accumulation of autolysosomes were detected by transmission electron microscopy (TEM).

The contractile tension of the genioglossus in Group OSA was significantly lower than that in the control group. The ratio of LC3II/LC3I and the levels of Beclin-1, PINK1 and Parkin were higher in Group OSA than that in the control group. And the abnormal changes were tended to be normal after MAD treatment. The mitochondrial structure was disrupted, and the number of autolysosomes increased in C2C12 after 24 h of hypoxia.

MAD treatment in male rabbits may decrease the contractile tension of the genioglossus and increase the level of mitochondrial autophagy caused by OSA. And the mechanism of mitochondrial autophagy was mediated by the PINK1/Parkin pathway in male rabbits.

Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by progressive cognitive decline and distinct neuropathological features. The absence of a definitive cure presents a significant challenge in neurology and neuroscience. Early clinical manifestations, such as memory retrieval deficits and apathy, underscore the need for a deeper understanding of the disease's underlying mechanisms. While amyloid-β plaques and tau neurofibrillary tangles have dominated research efforts, accumulating evidence highlights mitochondrial dysfunction as a central factor in AD pathogenesis. Mitochondria, essential cellular organelles responsible for energy production necessary for neuronal function become impaired in AD, triggering several cellular consequences. Factors such as oxidative stress, disturbances in energy metabolism, failures in the mitochondrial quality control system, and dysregulation of calcium release are associated with mitochondrial dysfunction. These abnormalities are closely linked to the neurodegenerative processes driving AD development and progression. This review explores the intricate relationship between mitochondrial dysfunction and AD pathogenesis, emphasizing its role in disease onset and progression, while also considering its potential as a biomarker and a therapeutic target.

Damaged mitochondria can be cleared from the cell by mitophagy, using a pathway formed by the recessive Parkinson's disease genes PINK1 and Parkin. How mitochondrial damage is sensed by the PINK1-Parkin pathway, however, remains uncertain. Here, using a Parkin substrate-based reporter in genome-wide screens, we identified that diverse forms of mitochondrial damage converge on loss of mitochondrial membrane potential (MMP) to activate PINK1. Consistently, the MMP but not the presequence translocase-associated motor (PAM) import motor provided the essential driving force for endogenous PINK1 import through the inner membrane translocase TIM23. In the absence of TIM23, PINK1 arrested in the translocase of the outer membrane (TOM) during import. The energy-state outside of the mitochondria further modulated the pathway by controlling the rate of new PINK1 synthesis. Our results identify separation of PINK1 from TOM by the MMP, as the key damage-sensing switch in the PINK1-Parkin mitophagy pathway.

MFN2-Halo is a quantitative single-cell reporter of PINK1-Parkin activation.Diverse forms of mitochondrial damage, identified in whole-genome screens, activate the PINK1-Parkin pathway by disrupting the mitochondrial membrane potential (MMP).The primary driving force for endogenous PINK1 import through the TIM23 translocase is the MMP with the PAM import motor playing a supporting role.Loss of TIM23 is sufficient to stabilize PINK1 in the TOM complex and activate Parkin.

Bladder cancer (BCa), particularly muscle-invasive bladder cancer (MIBC), is associated with poor prognosis, partly because of immune evasion driven by M2 tumor-associated macrophages (TAMs). Understanding the regulatory mechanisms of M2 macrophage polarization via PRKN-mediated mitophagy and histone lactylation (H3K18la) is crucial for improving treatment strategies.

A single-cell atlas from 46 human BCa samples was constructed to identify macrophage subpopulations. Bioinformatics analysis and experimental validation, including ChIP-seq and lactylation modulation assays, were used to investigate the role of PRKN in M2 macrophage polarization and its regulation by H3K18la.

Single-cell analysis revealed distinct macrophage subpopulations, including M1 and M2 types. PRKN was identified as a critical regulator of mitophagy in M2 macrophages, supporting their immunosuppressive function. Bulk RNA-seq and gene intersection analysis revealed a set of mitophagy-related macrophage polarization genes (Mito_Macro_RGs) enriched in mitophagy and immune pathways. Pseudotime analysis revealed that PRKN was upregulated during the M1-to-M2 transition. siRNA-mediated PRKN knockdown impaired M2 polarization, reducing the expression of CD206 and ARG1. ChIP-seq and histone lactylation modulation confirmed that H3K18la enhanced PRKN expression, promoting mitophagy and M2 polarization and thereby facilitating immune suppression and tumor progression.

Histone lactylation regulated PRKN-mediated mitophagy, promoting M2 macrophage polarization and contributing to immune evasion in BCa.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder in which mitochondrial dysfunction and neuroinflammation play crucial roles in its progression. Our previous studies found that cornuside from Cornus officinalis Sieb.Et Zucc is an anti-AD candidate, however, its underlying mechanism remains unknown. In the present study, AD mice were established by intracerebroventricular injection of Aβ1-42 and treated with cornuside (3, 10, 30 mg/kg) for 2 weeks. Cornuside significantly ameliorated behavioral deficits, protected synaptic plasticity and relieved neuronal damage in Aβ1-42 induced mice. Importantly, cornuside decreased NLRP3 inflammasome activation, characterized by decreased levels of NLRP3, ASC, Caspase-1, GSDMD, and IL-1β. Furthermore, cornuside promoted mitophagy accompanied by decreasing SQSTM1/p62 and promoting LC3B-I transforming into LC3B-II, via Pink1/Parkin signaling instead of FUNDC1 or BNIP3 pathways. In order to investigate the relationship between NLRP3 inflammasome and mitophagy in the neuroprotective mechanism of cornuside, we established an in-vitro model in BV2 cells exposed to LPS and Aβ1-42. And cornuside inhibited NLRP3 inflammasome activation and subsequent cytokine release, also protected neurons from damaging factors in microenvironment of conditional culture. Cornuside improved mitochondrial function by promoting oxidative phosphorylation and glycolysis, decreasing the production of ROS and mitochondrial membrane potential depolarization. Besides, mitophagy was also facilitated with increased colocalization of MitoTracker with LC3B and Parkin, and Pink1/Parkin, FUNDC1 and BNIP3 pathways were all involved in the mechanism of cornuside. By blocking the formation of autophagosomes by 3-MA, the protective effects on mitochondria, the inhibition on NLRP3 inflammasome as well as neuronal protection in conditional culture were eliminated. There is reason to believe that the promotion of mitophagy plays a key role in the NLRP3 inhibition of cornuside. In conclusion, cornuside re-establishes the mitophagy flux which eliminates damaged mitochondria and recovers mitochondrial function, both of them are in favor of inhibiting NLRP3 inflammasome activation, then alleviating neuronal and synaptic damage, and finally improving cognitive function.

Accumulating evidence supports an important role of phospholipase D3 (PLD3) in the pathogenesis of Alzheimer's disease (AD), while the actual expression level and distribution of PLD3 remains controversial in AD. Developing specific nanoprobes could be a promising strategy to understand PLD3 better, but there are limited approaches available in this field for a simple, reliable, and biocompatible biosensor. In this work, we report a PLD3-induced fluorescence resonance energy transfer (FRET) nanoprobe utilizing tetrahedral DNA nanostructures (TDNs) for visualizing the fluctuation of PLD3 at organ and subcellular levels in AD. Hydrolysis of PLD3 to a specific nucleotide strand on TDN will turn the FRET probe to an OFF state, which results in changes in fluorescent intensity. Immunofluorescent staining of brain sections proved the reliability of TDN nanoprobe to visualize PLD3 and the upregulation of PLD3 was observed in AD mice. Subsequent application of the nanoprobe uncovered PLD3 in the heart tissue of AD mice for the first time. Further investigations on the cellular level revealed a good colocalization of TDN nanoprobes with lysosomes in normal neurons, while their fluorescent signal overlaps better with mitochondria than lysosomes in AD neurons. Our finding provides not only insights into PLD3 but also an inspiring application of TDNs in the mechanism research of AD at multiple levels.

Fanconi Anemia (FA) is an autosomal recessive disorder characterized by diverse clinical manifestations such as aplastic anemia, cancer predisposition, and developmental defects including hypogonadism, microcephaly, organ dysfunction, infertility, hyperpigmentation, microphthalmia, and skeletal defects. In addition to the well-described defects in DNA repair, mitochondrial dysfunction due to defects in mitochondrial autophagy (mitophagy) is also associated with FA, although its contribution to FA phenotypes is unknown. This study focused on the FANCC gene, which, alongside other FA genes, is integral to DNA repair and mitochondrial quality control. In the present study, we created a FANCC mutant mouse model, based on a human mutation (FANCC c.67delG) that is defective in DNA repair but proficient in mitophagy. We found that the FANCC c.67delG mutant mouse model recapitulates some phenotypes observed in FA patients, such as cellular hypersensitivity to DNA cross-linking agents and hematopoietic defects. In contrast, FA phenotypes such as microphthalmia, hypogonadism, and infertility, present in FANCC-deficient mice, were absent in the FANCC c.67delG mice, suggesting that the N-terminal 55 amino acids of FANCC are dispensable for these developmental processes. Furthermore, the FANCC c.67delG mutation preserved mitophagy, and unlike the FANCC null mutation, did not lead to the accumulation of damaged mitochondria in cells or tissues. This study highlights the multifaceted nature of the FANCC protein, with distinct domains responsible for DNA repair and mitophagy. Our results suggest that developmental defects in FA may not solely stem from DNA repair deficiencies but could also involve other functions, such as mitochondrial quality control.

Mitochondria play a crucial role in human biology, affecting cellular processes at the smallest spatial scale as well as those involved in the functionality of the whole system. Imaging is the most important research tool for studying the fundamental role of mitochondria across these diverse spatial scales. A wide array of available imaging techniques have enabled us to visualize mitochondrial structure and behavior, as well as their effect on cells and tissues in a range from micrometers to centimeters. Each of the various imaging techniques that are available offers unique advantages tailored to specific research needs. Selecting an appropriate technique suitable for the scale and application of interest is therefore crucial, but can be challenging due to the large range of possibilities. The aim of this review is two-fold. First, we provide an overview of the available imaging techniques and discuss their strengths and limitations for applications across the sub-mitochondrial, cellular, tissue and organ levels for the imaging of mitochondria. Second, we identify opportunities for novel applications and advancement in the field. We emphasize the importance of integration across scales in mitochondrial imaging studies, particularly to bridge the gap between microscopic and non-invasive techniques. While integrating these diverse scales is challenging, primarily because such multi-scale approaches require expertise that spans different imaging modalities, we argue that integration has the potential to provide groundbreaking insights into mitochondrial biology. By providing a comprehensive overview of imaging techniques, this review paves the way for multi-scale imaging initiatives in mitochondrial research.

The immune evasion and prolonged survival of Staphylococcus aureus (S. aureus) within macrophages are key factors contributing to the difficulty in curing osteomyelitis. Although macrophages play a vital role as innate immune cells, the mechanisms by which S. aureus survives within them and suppresses host immune functions remain incompletely understood.

This study employed confocal microscopy, flow cytometry, ELISA, and siRNA technology to assess the survival capacity of S. aureus within macrophages and the impact of inflammatory cytokines on its persistence. Proteomics was used to investigate the potential mechanisms and differential proteins involved in S. aureus intracellular survival. Additionally, confocal microscopy, flow cytometry, Mdivi-1 intervention, and Western blot were utilized to validate the role of mitophagy in supporting S. aureus survival. The study further explored how the HDAC11/IL10 axis enhances mitophagy to promote intracellular S. aureus survival by using HDAC11 overexpression, siRNA, and rapamycin intervention combined with confocal microscopy and flow cytometry.

The findings demonstrated that IL10 promotes mitophagy to clear mitochondrial reactive oxygen species (mtROS), thereby enhancing the intracellular survival of S. aureus within macrophages. Additionally, we discovered that the transcriptional repressor of IL10, HDAC11, was significantly downregulated during S. aureus infection. Overexpression of HDAC11 and the use of the autophagy activator rapamycin further validated that the HDAC11/IL10 axis regulates mitophagy via the mTOR pathway, which is essential for supporting S. aureus intracellular survival.

This study reveals that S. aureus enhances IL10 production by inhibiting HDAC11, thereby promoting mitophagy and mtROS clearance, which supports its survival within macrophages. These findings offer new insights into the intracellular survival mechanisms of S. aureus and provide potential therapeutic approaches for the clinical management of osteomyelitis.

Dysfunctional mitochondria are present in many neurodegenerative diseases, such as spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph disease (MJD). SCA3/MJD, the most frequent neurodegenerative ataxia worldwide, is caused by the abnormal expansion of the polyglutamine tract (polyQ) at ataxin-3. This protein is known to deubiquitinate key proteins such as Parkin, which is required for mitophagy. Ataxin-3 also interacts with Beclin1 (essential for initiating autophagosome formation adjacent to mitochondria), as well as with the mitochondrial cristae protein TBK1. To identify other proteins of the mitophagy pathway (according to the KEGG database) that can interact with ataxin-3, here we developed a pipeline for in silico analyses of protein-protein interactions (PPIs), called auto-p2docking. Containerized in Docker, auto-p2docking ensures reproducibility and reduces the number of errors through its simplified configuration. Its architecture consists of 22 modules, here used to develop 12 protocols but that can be specified according to user needs. In this work, we identify 45 mitophagy proteins as putative ataxin-3 interactors (53% are novel), using ataxin-3 interacting regions for validation. Furthermore, we predict that ataxin-3 interactors from both Parkin-independent and -dependent mechanisms are affected by the polyQ expansion.

Low back pain (LBP) caused by nucleus pulposus degeneration and calcification leads to great economic and social burden worldwide. Unexpectedly, no previous studies have demonstrated the association and the underlying mechanism between nucleus pulposus tissue degeneration and calcification formation. Secreted Phosphoprotein 1 (SPP1) exerts crucial functions in bone matrix mineralization and calcium deposition. Here, a novel function of SPP1 is reported, namely that it can aggravate nucleus pulposus cells (NPs) degeneration by negatively regulating extracellular matrix homeostasis. The degenerated NPs have a higher mineralization potential, which is achieved by SPP1. Mechanistically, SPP1 can accelerate the degeneration of nucleus pulposus cells by activating integrin α5β1 (ITGα5/β1), aggravating mitochondrial damage and inhibiting mitophagy. SPP1-ITGα5/β1 axis inhibits mitophagy by PINK1/PARKIN pathway blockade. In conclusion, SPP1 activates ITGα5/β1 to inhibit mitophagy, accelerates NPs degeneration, and induces calcification, thereby leading to intervertebral disc degeneration (IVDD) and calcification, identifying the potentially unknown mechanism and relationship between IVDD and calcification. Important insights are provided into the role of SPP1 in nucleus pulposus calcification in IVDD by inducing nucleus pulposus cell senescence through inhibition of mitophagy and may help develop potential new strategies for IVDD treatment.

Glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme in the pentose phosphate pathway (PPP) in glycolysis. Glucose metabolism is closely implicated in the regulation of mitophagy, a selective form of autophagy for the degradation of damaged mitochondria. The PPP and its key enzymes such as G6PD possess important metabolic functions, including biosynthesis and maintenance of intracellular redox balance, while their implication in mitophagy is largely unknown. Here, via a whole-genome CRISPR-Cas9 screening, we identified that G6PD regulates PINK1 (phosphatase and tensin homolog [PTEN]-induced kinase 1)-Parkin-mediated mitophagy. The function of G6PD in mitophagy was verified via multiple approaches. G6PD deletion significantly inhibited mitophagy, which can be rescued by G6PD reconstitution. Intriguingly, while the catalytic activity of G6PD is required, the known PPP functions per se are not involved in mitophagy regulation. Importantly, we found a portion of G6PD localized at mitochondria where it interacts with PINK1. G6PD deletion resulted in an impairment in PINK1 stabilization and subsequent inhibition of ubiquitin phosphorylation, a key starting point of mitophagy. Finally, we found that G6PD deletion resulted in lower cell viability upon mitochondrial depolarization, indicating the physiological function of G6PD-mediated mitophagy in response to mitochondrial stress. In summary, our study reveals a novel role of G6PD as a key positive regulator in mitophagy, which bridges several important cellular processes, namely glucose metabolism, redox homeostasis, and mitochondrial quality control.

Human mitochondrial 12S ribosomal RNA (rRNA) 1555A>G mutation has been associated with aminoglycoside-induced and nonsyndromic deafness in many families worldwide. Our previous investigation revealed that the m.1555A>G mutation impaired mitochondrial translation and oxidative phosphorylation (OXPHOS). However, the mechanisms by which mitochondrial dysfunctions induced by m.1555A>G mutation regulate intracellular signaling for mitochondrial and cellular integrity remain poorly understood. Here, we demonstrated that the m.1555A>G mutation downregulated the expression of nucleus-encoded subunits of complexes I and IV but upregulated the expression of assemble factors for OXPHOS complexes, using cybrids derived from one hearing-impaired Chinese subject bearing the m.1555A>G mutation and from one hearing normal control lacking the mutation. These alterations resulted in the aberrant assembly, instability, and reduced activities of respiratory chain enzyme complexes I, IV, and V, rate of oxygen consumption, and diminished ATP production. Furthermore, the mutant cell lines carrying the m.1555A>G mutation exhibited decreased membrane potential and increased the production of reactive oxygen species. The aberrant assembly and biogenesis of OXPHOS impacted mitochondrial quality controls, including the imbalance of mitochondrial dynamics via increasing fission with abnormal mitochondrial morphology and impaired mitophagy. Strikingly, the cells bearing the m.1555A>G mutation revealed the upregulation of both ubiquitin-dependent and independent mitophagy pathways, evidenced by increasing levels of Parkin, Pink, BNIP3 and NIX, respectively. The m.1555A>G mutation-induced deficiencies ameliorate the cell homeostasis via elevating the autophagy process and upregulating apoptotic pathways. Our findings provide new insights into pathophysiology of mitochondrial deafness arising from reshaping mitochondrial and cellular homeostasis due to 12S rRNA 1555A>G mutation.

Intervertebral disc degeneration (IDD) is a major cause of low back pain (LBP), and effective therapies are still lacking. Reactive oxygen species (ROS) stress induces NLRP3 inflammasome activation, and this, along with extracellular matrix metabolism (ECM) degradation in nucleus pulposus cells (NPCs), plays a crucial role in the progression of IDD. Daphnetin (DAP) is a biologically active phytochemical extracted from plants of the Genus Daphne, which possesses various bioactivities, including antioxidant properties. In the present study, we demonstrate that DAP significantly attenuates tert-butyl hydroperoxide (TBHP)-induced ECM degradation, oxidative stress and NLRP3 inflammasome activation in NPCs. Furthermore, DAP could facilitate mitophagy to increase the removal of damaged mitochondria, consequently reducing mitochondrial ROS accumulation and alleviating NLRP3 inflammasome activation. Mechanistically, we unveil that DAP activates mitophagy by stimulating the Nrf2/PINK1 signaling pathway in TBHP-induced NPCs. In vivo experiments further corroborate the protective effect of DAP against IDD progression in a rat model induced by disc puncture. Accordingly, our findings reveal that DAP could be a promising therapeutic candidate for the treatment of IDD.