Chemical and mechanical cues within the extracellular matrix (ECM) can initiate intracellular signaling that changes an array of fundamental cell functions. In recent work, studies of cell-ECM adhesion have deepened to include the influence of the physical ECM on cell metabolism. Since many biological processes involve metabolic programs, changes to cellular metabolism in response to cues in the ECM can have marked effects on cell health. In this review, we describe molecular mechanisms associated with cell-ECM adhesion that are key players in metabolism-induced changes to cell behaviors, including migration. We first review how changes to metabolite availability in the extracellular environment or manipulation of metabolic machinery in cells impact focal adhesions. We then connect this work to recent findings regarding the reverse relationship, namely, how the manipulation of focal adhesion proteins or integrins feeds back to alter cell metabolism. Finally, we consider the latest findings from studies that describe how the mechanical properties of the ECM, primarily stiffness and confinement, alter cellular metabolism. We identify key areas of future investigation that may elucidate the molecular drivers that permit cells to respond to mechanical and chemical ECM cues by reprogramming their metabolism to better inform future diagnostics and therapeutics for disease states.

Leucyl-tRNA synthetase (LARS) is an essential multifunctional enzyme in mammals, pivotal in maintaining cellular protein and amino acid balance. It facilitates tRNA aminoacylation, initiating intracellular protein synthesis, and serves as an intracellular leucine sensor. The sensor function enables LARS to activate the mTORC1 pathway via Rag GTPase binding, playing a critical role in the regulation of protein synthesis. Despite its significance, the precise mechanisms of these functions are yet to be fully delineated. This study examines LARS and its role in modulating milk protein synthesis.

This study utilizes stable bovine mammary epithelial cell lines, LARS overexpression and LARS knockdown, validated by using Cell Counting Kit-8, Click-iT EdU, Western blot, real-time quantitative polymerase chain reaction, and immunoconfocal techniques.

Our findings show that LARS overexpression in bovine mammary epithelial cells (MAC-T) enhances cell proliferation and resultes intracellular leucine levels, thereby increasing casein production through the mTORC1 pathway. LARS enhances casein expression via the mechanistic Target of Rapamycin Complex 1, L-type Amino Transporters 1 (mTORC1-LAT1) pathway. This interaction is supported by a positive feedback mechanism from LAT1, enhancing the activation of the mTORC1 pathway. Additionally, LARS overexpression leads to increased LAT1 expression, improved LAT1 stability, and augmented its localization at the membrane. Our research indicates that LARS's enhancement of LAT1 expression is contingent on its dual roles in translation and leucine sensing, whereas its impact on LAT1 localization is exclusively dependent on its leucine sensing function.

LARS regulates LAT1 expression and membrane positioning through the mTORC1 pathway by detecting intracellular leucine levels, thereby influencing casein synthesis. These insights lay a theoretical groundwork for enhancing milk protein production and offer novel strategies for improving the quality of dairy products.

The lack of curative therapies for acute myeloid leukaemia (AML) remains an ongoing challenge despite recent advances in the understanding of the molecular basis of the disease. Here we identify the WNK1-OXSR1/STK39 pathway as a previously uncharacterised dependency in AML. We show that genetic depletion and pharmacological inhibition of WNK1 or its downstream phosphorylation targets OXSR1 and STK39 strongly reduce cell proliferation and induce apoptosis in leukaemia cells in vitro and in vivo. Furthermore, we show that the WNK1-OXSR1/STK39 pathway controls mTORC1 signalling via regulating amino acid uptake through a mechanism involving the phosphorylation of amino acid transporters, such as SLC38A2. Our findings underscore an important role of the WNK1-OXSR1/STK39 pathway in regulating amino acid uptake and driving AML progression.

The L-Leu amino acid transporter SLC7A5 has become an important target in inflammation and cancer. However, its role in acute graft-versus-host disease (aGVHD) and graft versus tumor (GVT) remains unexplored. We demonstrate that SLC7A5 deletion affected T cell activation, expansion and survival, and reduced IFNγ and granzyme B expression, thus controlling aGVHD, but without effect on tumor growth. On the other hand, dietary restriction of L-Leu reduced aGVHD by controlling T cell expansion, inducing apoptosis, and affecting granzyme B secretion. However, CD8 T cells did not fail to activate and express IFNγ in the absence of L-Leu, and showed an increased proportion of central memory T cells, which contributed to the GVT response. Deletion of SLC7A5 in T cells compromises mTORC1, glycolysis and mitochondrial oxidation. On the contrary, L-Leu removal reduced mTORC1 and completely blocked glycolysis but preserved mitochondrial function, favoring the generation of central memory responses and expression of stemness marker TCF1. In addition, our metabolomics data underscores the L-Leu-derived metabolite β-hydroxybutyrate as an important marker for SLC7A5-dependent allogenic T cell expansion in aGVHD.

Deciphering the processes through which cancer cells overcome stress, escape a repressive microenvironment and metastasize remains a challenge. Autophagy has been demonstrated to regulate cancer metastasis and C-terminal binding protein (CtBP) has been previously implicated in promoting metastasis in breast cancer. Here we identify the formation of a complex between CtBP and tripartite-motif-containing protein 28 (TRIM28) in the nucleus. Interestingly, this complex regulates the stability of both proteins, as the removal of either partner leads to degradation of the other. Furthermore, the stability of this complex in the nucleus inhibits autophagy through two independent mechanisms. Firstly, the formation of the complex sequesters TRIM28 in the nucleus, preventing its involvement in and its degradation through autophagy. Secondly, this complex participates in the suppression of PTEN expression and leads to inhibition of Unc-51-like kinase 1-mediated autophagy through activation of the protein kinase B-mammalian target of rapamycin pathway. Using mammary gland-specific CtBP-knockout mice, we demonstrate that repression of autophagy by the CtBP-TRIM28 complex modulates luminal duct formation. In breast cancer models, CtBP-TRIM28-dependent inhibition of cellular autophagy also promotes malignant metastasis. Therefore, our study reveals similarities between the mechanisms driving tumor progression and those involved in normal mammary gland development, potentially helping to pave the way toward targeted intervention in breast cancer metastasis.

The most malignant type of tumor in the brain is high-grade gliomas. Glioblastoma (GB), a grade 4 glioma, has the lowest 5-year survival rate and is associated with poor prognosis. An important signaling pathway involved in the pathogenesis of GB is the mammalian target of rapamycin (mTOR). Therefore, our study aimed to investigate how exosomes obtained from GB cells applied with different doses of hesperidin (HSP) affect miR- 9 and change the PDK1/AKT/mTOR pathway. For this purpose, T98G cells were treated with different doses (5, 10, 25, and 50 µg/mL) of HSP in combination with temozolomide (TMZ- 10 µg/mL). At the end of 24 h, cell viability, flow cytometry, and biochemical tests were performed. Additionally, exosomes were isolated from cells belonging to the control, TMZ, and high-concentration TMZ-HSP groups. miR- 9, PDK1, PTEN, AKT- 1, Bax, Bcl- 2, and Caspase 3 genes were expressed in both application groups and exosomes belonging to these groups. HSP was found to reduce the viability of GB cells significantly. The viability was significantly reduced, especially in the TMZ-HSP 50 µg/mL group. Depending on the dose, there was a significant increase in the LDH level and oxidative stress level. The apoptosis level was approximately 26% in the TMZ-HSP 50 µg/mL group. Along with all this, gene expressions changed at the exosomal level, and miR- 9 and miR- 146 levels increased. Similarly, it changed the expression of proteins related to the PDK1/AKT/mTOR signaling pathway at the exosomal level (p < 0.05). In conclusion, the TMZ-HSP combination showed anticancer effects in T98G cells, influenced exosome profiles, and appeared non-toxic and potentially beneficial to healthy cells, highlighting its potential therapeutic value.

Solute carrier (SLC) transporters govern most of the chemical exchange across cellular membranes and are integral to metabolic regulation, which in turn is linked to cellular function and identity. Despite their key role, individual functions of the SLC superfamily members were not evaluated systematically. We determined the metabolic and transcriptional profiles upon SLC overexpression in knock-out or wild-type isogenic cell backgrounds for 378 SLCs and 441 SLCs, respectively. Targeted metabolomics provided a fingerprint of 189 intracellular metabolites, while transcriptomics offered insights into cellular programs modulated by SLC expression. Beyond the metabolic profiles of 102 SLCs directly related to their known substrates, we identified putative substrates or metabolic pathway connections for 71 SLCs without previously annotated bona fide substrates, including SLC45A4 as a new polyamine transporter. By comparing the molecular profiles, we identified functionally related SLC groups, including some with distinct impacts on osmolyte balancing and glycosylation. The assessment of functionally related human genes presented here may serve as a blueprint for other systematic studies and supports future investigations into the functional roles of SLCs.

mTORopathies represent a group of neurodevelopmental disorders linked to dysregulated mTOR signaling, resulting in conditions such as tuberous sclerosis complex, focal cortical dysplasia, hemimegalencephaly, and Smith-Kingsmore Syndrome. These disorders often manifest with epilepsy, cognitive impairments, and, in some cases, structural brain anomalies. The mTOR pathway, a central regulator of cell growth and metabolism, plays a crucial role in brain development, where its hyperactivation leads to abnormal neuroplasticity, tumor formation, and heightened neuronal excitability. Current treatments primarily rely on mTOR inhibitors, such as rapamycin, which reduce seizure frequency and tumor size but fail to address underlying genetic causes. Advances in gene editing, particularly via CRISPR/Cas9, offer promising avenues for precision therapies targeting the genetic mutations driving mTORopathies. New delivery systems, including viral and non-viral vectors, aim to enhance the specificity and efficacy of these therapies, potentially transforming the management of these disorders. While gene editing holds curative potential, challenges remain concerning delivery, long-term safety, and ethical considerations. Continued research into mTOR mechanisms and innovative gene therapies may pave the way for transformative, personalized treatments for patients affected by these complex neurodevelopmental conditions.

Liver regeneration is a well-organized and phase-restricted process that involves chromatin remodeling and transcriptional alterations. However, the specific transcription factors (TFs) that act as key "switches" to initiate hepatocyte regeneration and organoid formation remain unclear. Comprehensive integration of RNA sequencing and ATAC sequencing reveals that ATF3 representing "Initiation_on" TF and ONECUT2 representing "Initiation_off" TF transiently modulate the occupancy of target promoters to license liver cells for regeneration. Knockdown of Atf3 or overexpression of Onecut2 not only reduces organoid formation but also delays tissue-damage repair after PHx or CCl4 treatment. Mechanistically, we demonstrate that ATF3 binds to the promoter of Slc7a5 to activate mTOR signals while the Hmgcs1 promoter loses ONECUT2 binding to facilitate regenerative initiation. The results identify the mechanism for initiating regeneration and reveal the remodeling of transcriptional landscapes and chromatin accessibility, thereby providing potential therapeutic targets for liver diseases with regenerative defects.

Systemic insulin resistance plays an important role in the pathogenesis of type 2 diabetes and its complications. Although impaired branched-chain amino acid (BCAA) metabolism has been reported to be involved in the development of diabetes, the relationship between cardiac BCAA metabolism and the pathogenesis of diabetic cardiomyopathy (DbCM) remains unclear.

The aim of this study was to investigate BCAA metabolism in insulin-resistant hearts by using a novel mouse model of DbCM.

The cardiac phenotypes of adipocyte-specific 3'-phosphoinositide-dependent kinase 1 (PDK1)-deficient (A-PDK1KO) mice were assessed by histological analysis and echocardiography. The metabolic characteristics and cardiac gene expression were determined by mass spectrometry or RNA sequencing, respectively. Cardiac protein expression was evaluated by Western blot analysis.

A-PDK1KO mouse hearts exhibited hypertrophy with prominent insulin resistance, consistent with cardiac phenotypes and metabolic disturbances previously reported as DbCM characteristics. RNA sequencing revealed the activation of BCAA uptake in diabetic hearts. In addition, the key enzymes involved in cardiac BCAA catabolism were downregulated at the protein level in A-PDK1KO mice, leading to the accumulation of BCAAs in the heart. Mechanistically, the accumulation of the BCAA leucine caused cardiac hypertrophy via the activation of mammalian target of rapamycin complex 1 (mTORC1).

A-PDK1KO mice closely mimic the cardiac phenotypes and metabolic alterations observed in human DbCM and exhibit impaired BCAA metabolism in the heart. This model may contribute to a better understanding of DbCM pathophysiology and to the development of novel therapies for this disease.

The majority of neuroendocrine neoplasms in pancreas are non-functional pancreatic neuroendocrine tumors (NF-PanNETs), which exhibit a high occurrence of distant metastases with limited therapeutic options. Here, we perform a comprehensive molecular characterization of 108 NF-PanNETs through integrative analysis of genomic, transcriptomic, proteomic, and phosphoproteomic profiles. Proteogenomic analysis provides functional insights into the genomic driver alterations of NF-PanNETs, revealing a potential mediator of MEN1 alterations using Men1-conditional knockout mice. Machine-learning-based modeling uncovers a three-protein signature as an independent prognostic factor, which is validated by an independent external cohort. Proteomic and phosphoproteomic-based stratification identifies four subtypes with distinct molecular characteristics, immune microenvironments, and clinicopathological features. Drug screening using patient-derived tumor organoids identifies cyclin-dependent kinase (CDK) 5 and Calcium Voltage-Gated Channel Subunit Alpha1 D (CACNA1D) as ubiquitous and subtype-specific targets, respectively, with in vivo validation using xenograft models. Together, our proteogenomic analyses illustrate a comprehensive molecular landscape of NF-PanNETs, revealing biological insights and therapeutic vulnerabilities.

In restricted regions of the rodent brain, neurogenesis persists throughout life, hinting that perhaps similar phenomena may exist in humans. Neural stem cells (NSCs) that reside within the ventricular-subventricular zone (V-SVZ) continually produce functional cells, including neurons that integrate into the olfactory bulb circuitry. The ability to achieve this feat is based on genetically encoded transcriptional programs that are controlled by environmentally regulated post-transcriptional signaling pathways. One such pathway that molds V-SVZ neurogenesis is the mTOR pathway. This pathway integrates nutrient sufficiency with growth factor signaling to control distinct steps of neurogenesis. Alterations in mTOR pathway signaling occur in numerous neurodevelopmental disorders. Here, we provide a narrative review for the role of the mTOR pathway in this process and discuss the use of this region to study the mTOR pathway in both health and disease.

Cancer cells are considered the most adaptable for their metabolic status, which supports growth, survival, rapid proliferation, invasiveness, and metastasis in a nutrient-deficient microenvironment. Since the discovery of altered glucose metabolism (aerobic glycolysis), which is generally known as a part of metabolic reprogramming and an innate trait of cancer cells, in 1930 via Dr. Otto Warburg, numerous studies have endeavored to recognize various aspects of cancer cell metabolism and find new methods for efficiently eradicating described cells by targeting their energy metabolism. In this way, the outcomes have mainly been promising. Accordingly, outlining the related results will indeed assist us in making a definitive path for developing targeted therapy strategies based on cancer cell-altered metabolism. The present study reviews the key features of cancer cell metabolism and treatment strategies based on them. It emphasizes the importance of targeting cancer cell dysregulated metabolic pathways that influence the cell energy supply and manage cancer cell growth and survival. This trial also introduces a multimodal therapeutic strategy hypothesis, a potential next-generation combination therapy approach, and suggests interdisciplinary research to recognize the complexities of cancer metabolism and exploit them for designing more efficacious cancer therapeutic strategies.

Microplastics (MPs) are widely distributed environmental pollutants around the world. Although studies have demonstrated that MPs have adverse effects on human health, the relationship between MPs and tumors remains unclear. The gut is the main site of microplastics absorption, and the function of MPs in the chemoresistance and progression of colorectal cancer (CRC) needs more investigation. Here, we show that MPs exist in human CRC tissues for the first time by using a laser direct infrared chemical imaging system. MPs can cause an increase in CRC incidence in animal models and promote resistance to oxaliplatin. It is illustrated that the uptake of MPs enhances levels of autophagy by activating the mTOR pathway. MPs can also promote the disorder of intestinal flora and intestinal inflammation, serving as an essential component in the onset and advancement of CRC. These results indicated that microplastic pollutants in colorectal cancer could mediate protective autophagy through the mTOR/ULK1 axis, which is one of the new reasons for chemo-resistance in CRC under the background of increasingly serious microplastics pollution. This study identified the adverse effects of MPs on colorectal cancer progression and chemotherapy prognosis, and attempted to block the intake of MPs to propose a novel approach for clinical precision treatment.

The oncogene LAPTM4B (encoding lysosome-associated protein transmembrane-4β), first cloned in hepatocellular carcinoma cells, is located on chromosome 8q22.1 and encodes two isoforms, LAPTM4B-35 and LAPTM4B-24. LAPTM4B proteins have four transmembrane structural domains and are mainly distributed in lysosomal and endosomal membranes of cells. Studies have shown that LAPTM4B is overexpressed in a variety of cancers, in which the genetic polymorphism of LAPTM4B is associated with tumor susceptibility. LAPTM4B also regulates various cell signaling pathways, interacts with autophagy-related proteins and ceramides, and regulates the autophagy process and the release of exosomes, which in turn affect the survival and drug resistance of tumor cells. In conclusion, this paper summarizes recent research on LAPTM4B, aiming to explore the role and potential mechanisms of LAPTM4B in a variety of tumors.

Pancreatic cancer is a highly malignant digestive tumor. Glutamine metabolism is one of the important sources of tumors. N6-methyladenosine (m6A) modification plays a key role in regulating tumor metabolism and holds promise as a therapeutic target in various cancers, including pancreatic cancer. Disrupting m6A regulation of glutamine metabolism could impair tumor growth, offering potential new therapeutic strategies. However, the functional role of m6A modifications in pancreatic cancer, especially in glutamine metabolism, remains poorly understood.

The Cancer Genome Atlas (TCGA) dataset and GEPIA bioinformatics tool were used to identify the relationship between m6A related proteins and the glutamine metabolism-associated genes, respectively. The biological effects of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) were investigated using in vitro and in vivo models. Methylated RNA immunoprecipitation sequencing (MeRIP-seq), MeRIP-PCR and RNA immunoprecipitation (RIP) were used to identify solute carrier family 1 member 5 (SLC1A5) as a direct target of IGF2BP2.

We found that IGF2BP2 expression and SLC1A5 were significantly correlated and both highly expressed in pancreatic cancer could predict poor prognosis in patients with pancreatic cancer. Functionally, silencing IGF2BP2 suppressed tumor growth and also inhibited glutamine uptake by tumor cells. Mechanistically, IGF2BP2 induced the m6A-SLC1A5-mTORC1 axis, facilitating the uptake of glutamine by pancreatic cancer cells and accelerate the progress of pancreatic cancer. Furthermore, silencing IGF2BP2 can enhance the sensitivity of pancreatic cancer to radiotherapy and chemotherapy.

Our findings suggest that IGF2BP2 promotes pancreatic cancer by activating the m6A-SLC1A5 -mTORC1 axis. Targeting the m6A machinery, particularly IGF2BP2, offers a novel therapeutic avenue for pancreatic cancer treatment. By disrupting the regulation of glutamine metabolism, we provide new insights into how m6A-based therapies could enhance the efficacy of current treatments and offer hope for improving patient outcomes in this difficult-to-treat cancer.

Background/Objectives: Endoplasmic reticulum (ER) stress occurs when ER homeostasis is disrupted, leading to the accumulation of misfolded or unfolded proteins. This condition activates the unfolded protein response (UPR), which aims to restore balance or trigger cell death if homeostasis cannot be achieved. In cancer, ER stress plays a key role due to the heightened metabolic demands of tumor cells. This review explores how metabolomics can provide insights into ER stress-related metabolic alterations and their implications for cancer therapy. Methods: A comprehensive literature review was conducted to analyze recent findings on ER stress, metabolomics, and cancer metabolism. Studies examining metabolic profiling of cancer cells under ER stress conditions were selected, with a focus on identifying potential biomarkers and therapeutic targets. Results: Metabolomic studies highlight significant shifts in lipid metabolism, protein synthesis, and oxidative stress management in response to ER stress. These metabolic alterations are crucial for tumor adaptation and survival. Additionally, targeting ER stress-related metabolic pathways has shown potential in preclinical models, suggesting new therapeutic strategies. Conclusions: Understanding the metabolic impact of ER stress in cancer provides valuable opportunities for drug development. Metabolomics-based approaches may help identify novel biomarkers and therapeutic targets, enhancing the effectiveness of antitumor therapies.

Pathological cardiac remodeling (REM), caused by various pathological factors and characterized by changes in cardiac structure and geometry, is strongly associated with heart failure (HF). It damages cardiac tissue, alters energy metabolism, increases oxidative stress, and cause matrix metalloproteinase activation, cardiomyocyte hypertrophy, and interstitial fibrosis, leading to HF. REM determines the outcome of cardiovascular disease. Current treatments have limitations. REM is associated with cardiac energetic remodeling, and modulation of metabolic substrates may slow down the disease. Perilipin 5 (Plin5), positioned as a structural protein located on the surface of lipid droplets (LDs), is abundant in tissues and cells that rely on mitochondrial β-oxidation for energy production. It is the most recently identified member of the perilipin protein (PAT) family, with a notable enrichment in the cardiac muscle. Emerging evidence highlights the critical role of intracellular LD in the regulation of energy metabolism, with metabolic disruptions of LD being directly correlated with the incidence of metabolic disease. As a key barrier to LD, Plin5 is instrumental in controlling the catabolism of LD and regulating the metabolism and transport of fatty acids (FAs). As a protectant against excessive β-oxidation of free fatty acids (FFAs), Plin5 acts to isolate and neutralize overly oxidized fatty acids, thereby shielding the heart from myocardial remodeling instigated by a variety of etiological factors. This protective mechanism helps to ameliorate the progression of persistent and detrimental myocardial remodeling, which can otherwise lead to the development of severe heart failure. This systematic review attempts to delineate the metabolic disorders associated with pathological cardiac remodeling, focusing on the properties and regulatory mechanisms of Plin5. By synthesising current literature, it investigates the pivotal role of Plin5 in modulating the distinctive attributes, initiating factors, and molecular signaling networks underpinning pathological cardiac remodeling.

Glutamine plays a role in cell signaling that regulates gene expression and impacts tumorigenesis. However, it is still unclear how glutamine transduces signals in cells. Here, we show that glutamine binds to heat shock cognate protein 70 (HSC70) to stimulate the deubiquitinase otubain domain containing protein (OTUD4) independently of known glutamine metabolic or signaling pathways, resulting in lactate dehydrogenase A (LDHA) stabilization via the microautophagy-lysosome pathway, increased lactate production and decreased expression of interferon (IFN)-β and its targets, hallmarks of immunogenic cell death (ICD). In cancer cell lines and patient-derived organoids and xenografts, glutamine depletion or glutamine transport inhibition combined with ICD-inducing chemotherapeutic drugs synergistically activates IFN-β, promotes CD8+ T cell recruitment, and inhibits cancer cell growth via the OTUD4/LDHA axis. CD8 expression is negatively correlated with expression of the glutamine transporter alanine/serine/cysteine transporter 2 (ASCT2), OTUD4, and LDHA in cancer patients. Thus, we identify an intracellular glutamine signaling pathway, and targeting this pathway is a promising strategy for cancer treatment.

Root causal gene expression levels - or root causal genes for short - correspond to the initial changes to gene expression that generate patient symptoms as a downstream effect. Identifying root causal genes is critical towards developing treatments that modify disease near its onset, but no existing algorithms attempt to identify root causal genes from data. RNA-sequencing (RNA-seq) data introduces challenges such as measurement error, high dimensionality and non-linearity that compromise accurate estimation of root causal effects even with state-of-the-art approaches. We therefore instead leverage Perturb-seq, or high-throughput perturbations with single-cell RNA-seq readout, to learn the causal order between the genes. We then transfer the causal order to bulk RNA-seq and identify root causal genes specific to a given patient for the first time using a novel statistic. Experiments demonstrate large improvements in performance. Applications to macular degeneration and multiple sclerosis also reveal root causal genes that lie on known pathogenic pathways, delineate patient subgroups and implicate a newly defined omnigenic root causal model.

An inadequate amino acid (AA) supply in animals under protein-restricted conditions can slow skeletal muscle growth. Protein translation can be activated by short-term leucine (Leu) stimulation; however, whether muscle mass increases under long-term Leu supplementation and how the gut and muscle respond to Leu supplementation are largely unknown. In this study, we investigated if muscle mass increases with long-term Leu supplementation under protein-restricted conditions. We identified changes in the link between the gut and muscles under different amino acid supply conditions, using goats as the study object. A total of 27 Xiangdong black male goats with average initial body weight (BW) of 10.88 ± 1.22 kg were randomly divided into three dietary treatments: a normal protein diet (NP, 14.24% crude protein [CP]); a low protein diet (LP, 8.27% CP with supplemental 1.66% rumen-protected lysine [RPLys] and 0.09% rumen-protected methionine [RPMet]); and LP diet with rumen-protected Leu (RPLeu) (LP + RPLeu, 8.75% CP with supplemental 1.66% RPLys, 0.09% RPMet and 1.46% RPLeu). The animal trial lasted for 110 d, consisting of 20 d of adaptation and a 90 d of experimental period. The results showed that long-term protein restriction increased gut tryptophan hydroxylase 1 (TPH1) activity (P < 0.001), tryptophan (Trp) catabolism (P < 0.001), and 5-hydroxytryptamine (5-HT) synthesis (P < 0.001), which all subsequently reduced goat appetite. Long-term Leu supplementation inhibited 5-HT synthesis (P < 0.001), decreased Trp catabolism in the gut, and increased appetite in goats. Long-term protein restriction enhanced jejunal and ileal branched-chain amino acid transferase (BCAT) (P < 0.001) and branched-chain α-Keto acid dehydrogenase (BCKD) (P = 0.048) activities, which increased branched-chain amino acid (BCAA) catabolism. Immunofluorescence results showed that protein restriction decreased the intestinal mucosal expression of solute carrier family 1 member 5 (SLC1A5) (P = 0.032) and solute carrier family 7 member 5 (SLC7A5) (P < 0.001), reduced BCAA transport from the mucosa to the blood, lowered BCAA levels in the blood (P < 0.001). Western blot results showed that protein restriction inhibited mammalian target of rapamycin (mTOR) pathway activation in goat muscles. Leu supplementation increased BCAA translocation from the intestine to the blood and promoted activation of the muscle mTOR pathway and protein synthesis. In conclusion, our results suggest that Leu supplementation in low-protein diets improves appetite and alleviates the inhibition of muscle protein synthesis in goats.

Energy metabolism is indispensable for sustaining physiological functions in living organisms and assumes a pivotal role across physiological and pathological conditions. This review provides an extensive overview of advancements in energy metabolism research, elucidating critical pathways such as glycolysis, oxidative phosphorylation, fatty acid metabolism, and amino acid metabolism, along with their intricate regulatory mechanisms. The homeostatic balance of these processes is crucial; however, in pathological states such as neurodegenerative diseases, autoimmune disorders, and cancer, extensive metabolic reprogramming occurs, resulting in impaired glucose metabolism and mitochondrial dysfunction, which accelerate disease progression. Recent investigations into key regulatory pathways, including mechanistic target of rapamycin, sirtuins, and adenosine monophosphate-activated protein kinase, have considerably deepened our understanding of metabolic dysregulation and opened new avenues for therapeutic innovation. Emerging technologies, such as fluorescent probes, nano-biomaterials, and metabolomic analyses, promise substantial improvements in diagnostic precision. This review critically examines recent advancements and ongoing challenges in metabolism research, emphasizing its potential for precision diagnostics and personalized therapeutic interventions. Future studies should prioritize unraveling the regulatory mechanisms of energy metabolism and the dynamics of intercellular energy interactions. Integrating cutting-edge gene-editing technologies and multi-omics approaches, the development of multi-target pharmaceuticals in synergy with existing therapies such as immunotherapy and dietary interventions could enhance therapeutic efficacy. Personalized metabolic analysis is indispensable for crafting tailored treatment protocols, ultimately providing more accurate medical solutions for patients. This review aims to deepen the understanding and improve the application of energy metabolism to drive innovative diagnostic and therapeutic strategies.

As a long-standing atmospheric pollutant, ozone (O3) exerts enduring effects on biological health. However, experimental research on its impact on organism lifespan and generational effects is limited. This study exposed three generations of fruit flies (Drosophila melanogaster) to O3, revealing a shortened lifespan across generations. Specifically, after O3 exposure, the lifespan of the F2 generation was significantly reduced compared with F0 and F1 generations, indicating a cumulative multigenerational effect. Transcriptome analysis unveiled significant disruptions in metabolic pathways, notably the insulin signaling pathway. Subsequent qRT-PCR analysis showed elevated mRNA levels of insulin pathway-related genes (dilp2, dilp3, dilp5, InR, and TOR), alongside decreased expression levels of FOXO, 4E-BP, and Atg5 in flies exposed to O3. Notably, knocking down dilp2, rather than dilp3, dilp5, and InR, rescued the O3-induced lifespan shortening. Overall, O3 exposure triggered activation of the dilp2-mediated InR-FOXO/TOR-4E-BP-Atg5 signaling pathway, potentially contributing to shortened lifespan with cumulative effects. This study highlights the viability of employing fruit flies as a model to evaluate the multigenerational toxicity of environmental pollutants, particularly atmospheric pollutants.

Serine metabolism provides important metabolic intermediates that support the rapid proliferation of tumor cells. However, the role of serine metabolism in esophageal squamous cell carcinoma (ESCC) and the underlying mechanism remains unclear. Here, we show that serine starvation predominantly inhibits ESCC cell proliferation by suppressing purine nucleotides and NADPH synthesis. Mechanistically, serine depletion led to the accumulation of aminoimidazole carboxamide ribonucleoside (AICAR), an intermediate metabolite of de novo purine synthesis, and AMP/ATP ratio. These increases activated 5'-AMP-activated kinase (AMPK), which subsequently inhibited the mTORC1 pathway by phosphorylating Raptor at Ser792. Moreover, serine depletion decreased NADPH level followed by elevated reactive oxygen species (ROS) production and DNA damage, which induced p53-p21 mediated G1 phase cell cycle arrest. Conversely, serine starvation activated transcription factor 4 (ATF4)-mediated robust expression of phosphoserine aminotransferase 1 (PSAT1) which in turn promoted compensatory endogenous serine synthesis, thus maintaining ESCC cell survival under serine-limited conditions. Accordingly, serine deprivation combined with PSAT1 inhibition significantly suppressed ESCC tumor growth both in vitro and in vivo. Taken together, our findings demonstrate that serine starvation suppresses the proliferation of ESCC cells by disturbing the synthesis of purine nucleotides and NADPH, and the combination of serine deprivation and PSAT1 inhibition significantly impairs ESCC tumor growth. Our study provides a theoretical basis for targeting serine metabolism as a potential therapeutic strategy for ESCC.

Hepatocellular carcinoma (HCC) poses a substantial global health burden, with poor prognosis and high mortality rates. Dysregulated lipid metabolism has emerged as a critical driver of HCC progression. While mTORC1 signaling is known to promote lipid synthesis in HCC, the regulatory mechanisms governing mTORC1 remain largely unclear. Here, we demonstrate that mTORC1 inhibition significantly reduces lipogenesis in HCC and uncover a regulatory axis involving the transcription factor ATF3 and the leucine-arginine transporter SLC7A7. Transcriptomic analysis of HCC patients reveals an inverse correlation between ATF3 expression and lipid synthesis, a finding corroborated by experimental validation. Mechanistically, ATF3 suppresses mTORC1 signaling, thereby inhibiting lipid biosynthesis, with SLC7A7 identified as a key intermediary in this process. Specifically, ATF3 binds to the enhancer region of SLC7A7, driving its transcriptional activation and subsequently restraining mTORC1 activity. Functional assays in ATF3-overexpressing and -knockdown HCC cell lines further confirm ATF3's role as a tumor suppressor. Our study identifies a novel ATF3-SLC7A7-mTORC1 regulatory axis that attenuates lipogenesis and tumorigenesis in HCC, establishing a critical link between lipid metabolism and hepatocarcinogenesis. These findings offer new insights into potential therapeutic targets for the treatment of HCC.

Glioblastoma (GBM) is a prevalent and refractory type of brain tumor. Over the past two decades, there have been minimal advancements in GBM therapy. The current standard treatment involves surgical excision followed by radiation and chemotherapy. Compared to other tumors, GBM is more challenging to treat due to the presence of glioma stem-like cells (GSCs) and the blood-brain barrier, resulting in an extremely low survival rate. Mitochondria play a critical role in tumor respiration, metabolism, and multiple signaling pathways involved in tumor formation, progression, and cell apoptosis. Consequently, mitochondria represent promising targets for developing novel anticancer agents, including those targeting oxidative phosphorylation, reactive oxygen species (ROS), mitochondrial transfer, and mitophagy. This review outlines the mitochondrial-related therapeutic targets in GBM, highlighting the potential of mitochondria as a target for GBM treatment.

Glutamine, akin to glucose, is a fundamental nutrient for human physiology. Tumor progression is often accompanied by elevated glutamine consumption, resulting in a disrupted nutritional balance and metabolic reprogramming within the tumor microenvironment. Furthermore, immune cells, which depend on glutamine for metabolic support, may experience functional impairments and dysregulation. Although the role of glutamine in tumors has been extensively studied, the specific impact of glutamine competition on immune responses, as well as the precise cellular alterations within immune cells, remains incompletely understood. In this review, we summarize the consequences of glutamine deprivation induced by tumor-driven glutamine uptake on immune cells, assessing the underlying mechanisms from the perspective of various components of the immune microenvironment. Additionally, we discuss the potential synergistic effects of glutamine supplementation and immunotherapy, offering insights into future research directions. This review provides compelling evidence for the integration of glutamine metabolism and immunotherapy as a promising strategy in cancer therapy.

The epidermal growth factor receptor mutant (EGFRm) non-small cell lung cancer (NSCLC) has a unique "cold" immune profile. DNA damage repair (DDR) genes are closely related to tumorigenesis and the effectiveness of immunotherapy in many tumors. However, the role and mechanism of DDR in the genesis and progression of EGFRm NSCLC remain unclear.

This study included 101 EGFRm NSCLC samples from The Cancer Genome Atlas (TCGA) dataset and a GSE31210 dataset (external set) from the GEO database. Cluster analysis was used to identify different subtypes of EGFRm NSCLC based on the expression of DDR genes. Univariate and LASSO regression analysis was used to develop a DDR-based predictive model. The prognostic significance of this model was assessed using Cox regression, Kaplan-Meier, and receiver operating characteristic (ROC) curve analyses. Bioinformatics analysis was performed to investigate the clinicopathological characteristics and immune profiles associated with this model. In vitro experiment was performed to testify the role of DDR genes in EGFRm NSCLC.

We identified two subtypes of EGFRm NSCLC: DDR-activated and DDR-suppressed. The DDR-activated subtype showed more aggressive clinical behavior and poorer prognosis and was more responsive to immunotherapy. A prognostic model for EGFRm NSCLC was constructed using four DDR genes: CAPS, FAM83A, IGLV8-61, and SLC7A5. The derived risk score could serve as an independent prognostic indicator. High- and low-risk patients exhibited distinct clinicopathological characteristics, immune profiles, and responses to immunotherapy. The T-cell inflammation and Tumor Immune Dysfunction and Exclusion (TIDE) scores differed between the high- and low-risk subgroups, with both showing enhanced effectiveness of immunotherapy in the low-risk subgroup. Targeted therapy such as BI.2536, an inhibitor of polo-like kinase 1, could be effective for patients with high-risk EGFRm NSCLC. Meanwhile, in vitro detection approved the role of DDR genes in EGFRm NSCLC response.

This study demonstrated a diversity of DDR genes in EGFRm NSCLC and developed a predictive model using these genes. This model could assist in identifying potential candidates for immunotherapy and in assessing personalized treatment and prognosis of patients with EGFRm NSCLC.

Glutamine is the most abundant amino acid in human blood and muscle, and is integral to a wide variety of functions in cancer cells. However, the inability to monitor the subcellular distribution of glutamine in real-time has obscured understanding of glutamine metabolism under physiological and pathological conditions. Here, we report the development of a genetically encoded fluorescent sensor and demonstrate how this GlnBP-cpYFP fusion "GlutaR sensor" undergoes glutamine-induced conformational changes reflected in detectable fluorescence responses. Obtained after iterative screening of approximately 1,600 variants, GlutaR exhibits a ratiometric readout, fast response kinetics, and high responsivity (R488/405 of ~1000 %), and we demonstrate its selectivity for monitoring glutamine fluctuations in multiple cell types. Additionally, using digitonin permeabilization of GlutaR HeLa cells, we generated a calibration curve and performed in situ titration to quantify free glutamine concentrations in subcellular compartments (cytosol, nucleus, mitochondria). Subsequently, we applied GlutaR to investigate how chemical and genetic inhibition of glutamine synthetase (GS) and glutaminase (GLS) differentially alter glutamine levels in subcellular compartments. Finally, we demonstrate GlutaR's ability to monitor dynamic glutamine levels in muscle and liver tissues of diabetic mice in vivo. These findings collectively demonstrate GlutaR as a versatile tool for the spatiotemporal characterization of glutamine metabolism in living cells and tissues.

Human primary (hpBMEC) and induced pluripotent stem cell (iPSC)-derived brain microvascular endothelial-like cells (hiBMEC) are interchangeably used in blood-brain barrier models to study neurological diseases and drug delivery. Both hpBMEC and hiBMEC use glutamine as a source of carbon and nitrogen to produce metabolites and build proteins essential to cell function and communication. We used metabolomic, transcriptomic, and computational methods to examine how hpBMEC and hiBMEC metabolize glutamine, which may impact their utility in modeling the blood-brain barrier. We found that glutamine metabolism was systemically different between the two cell types. hpBMEC had a higher metabolic rate and produced more glutamate and GABA, while hiBMEC rerouted glutamine to produce more glutathione, fatty acids, and asparagine. Higher glutathione production in hiBMEC correlated with higher oxidative stress compared to hpBMEC. α-ketoglutarate (α-KG) supplementation increased glutamate secretion from hiBMEC to match that of hpBMEC; however, α-KG also decreased hiBMEC glycolytic rate. These fundamental metabolic differences between BMEC types may impact in vitro blood-brain barrier model function, particularly communication between BMEC and surrounding cells, and emphasize the importance of evaluating the metabolic impacts of iPSC-derived cells in disease models.

Cancer cells must reprogram their metabolism to sustain rapid growth. This is accomplished in part by switching to aerobic glycolysis, uncoupling glucose from mitochondrial metabolism, and performing anaplerosis via alternative carbon sources to replenish intermediates of the tricarboxylic acid (TCA) cycle and sustain oxidative phosphorylation (OXPHOS). While this metabolic program produces adequate biosynthetic intermediates, reducing agents, ATP, and epigenetic remodeling cofactors necessary to sustain growth, it also produces large amounts of byproducts that can generate a hostile tumor microenvironment (TME) characterized by low pH, redox stress, and poor oxygenation. In recent years, the focus of cancer metabolic research has shifted from the regulation and utilization of cancer cell-intrinsic pathways to studying how the metabolic landscape of the tumor affects the anti-tumor immune response. Recent discoveries point to the role that secreted metabolites within the TME play in crosstalk between tumor cell types to promote tumorigenesis and hinder the anti-tumor immune response. In this review, we will explore how crosstalk between metabolites of cancer cells, immune cells, and stromal cells drives tumorigenesis and what effects the competition for resources and metabolic crosstalk has on immune cell function.