Multi-organ failure frequently complicates sepsis, with lungs being the primary target. T helper (Th) cell activation and phenotypic imbalance among them contribute significantly to sepsis-associated lung injury. Additionally, the complement system could regulate the polarized phenotype of T lymphocytes. Therefore, this study investigated the effect of C5a/C5a receptor (C5aR)/Peptidylarginine deiminase 4 (PAD4) on the Th1/Th2 ratio in sepsis-induced lung injury.

ELISA was used to detect the expression of PAD4, HBP, MPO, IL-1β, IL-10, IL-6, IL-4, syndecan-1, endocan and H3Cit. An LPS-induced septic lung injury mouse model was constructed, with HE and PAS stains evaluating lung damage. BCA kit quantified BALF total protein, Western blot examined C5aR, syndecan-1, endocan, PAD4 levels, while TUNEL and flow cytometry assessed tissue cellular apoptosis. Furthermore, flow cytometry was used to detect the +Th1 and Th2 cells proportion in peripheral blood, and CCK-8 was used to detect BEAS-2B activity.

The results indicated that PAD4 and inflammatory factors were increased in lesion samples compared with controls. In sepsis-induced lung injury mice, addition of GSK484, a PAD4 inhibitor, effectively alleviated sepsis-induced lung edema and inflammatory responses. GSK484 was found to inhibit C5a/C5aR expression and suppress apoptosis and lung injury. Furthermore, GSK484 markedly inhibited Th1 cell phenotypes in vitro. Additionally, GSK484 intervention on Th1 cell phenotype further affected lung epithelial cell injury.

In summary, we revealed the mechanism of C5a/C5aR-induced PAD4 upregulation via neutrophil activation in sepsis-associated lung injury, causing a Th1/Th2 imbalance and lung injury, providing a novel approach for sepsis-associated lung injuries treatment.

Hearing loss is a common disability affecting the world's population. Currently, its treatment options are limited. Adeno-associated virus (AAV)-mediated inner ear gene therapy has shown great promise as a treatment for hereditary hearing loss. However, the host immune responses to AAV-mediated gene therapy in the mammalian inner ear is not well understood. In this study, two serotypes of AAV vectors were injected individually into the mouse inner ear to evaluate the host innate and adaptive immune responses up to 1 month after inner ear gene delivery. Our results suggest that the host innate and adaptive immune responses to AAV-mediated inner ear gene delivery are limited and mild, which is favorable for its clinical translation.

Following the inadequacy of global plastic pollution control measures, microplastic (MP) pollution is posing new challenges to human health. In recent years, MPs have been detected in various human tissues, including their first identification in human kidneys in 2023. MPs can reach the kidneys through inhalation, oral ingestion, and intravascular injection, and they can be excreted via urine. Based on the latest research, this article reviews the nephrotoxicity of MPs and proposes a filtration-reabsorption-translocation hypothesis regarding the potential renal excretion mechanism of MPs. Short-term exposure to MPs can induce oxidative stress, resulting in endoplasmic reticulum (ER) stress, inflammatory responses, and lipid metabolism disorders, while long-term exposure may result in renal fibrosis mediated by ferroptosis. The nephrotoxicity of MPs is associated with particle size, though not in a linear manner. A specific size range appears to exhibit more significant kidney toxicity. Furthermore, oral exposure may activate the complement system in the kidneys through the gut-kidney axis, with the C5a/C5aR pathway playing an important role in this process. In conclusion, MPs present a substantial threat to human kidney health. Considering the existing research limitations, it is imperative to urgently investigate the effects of MPs at realistic environmental exposure concentrations on human kidneys and to explore strategies for mitigating their nephrotoxicity.

Sepsis, a lethal organ dysfunction syndrome driven by aberrant host responses to infection, intertwines excessive inflammatory responses and dysregulated coagulation processes in its pathophysiology. Emerging research reveals the complement terminal membrane attack complex C5b-9 orchestrates ultralarge von Willebrand factor (ULVWF) release from vascular endothelial cells (ECs) through multifaceted mechanisms: C5b-9 compromises EC membrane integrity, activates calcium influx cascades, and provokes NLRP3 inflammasome signaling, triggering massive exocytosis of ULVWF stored within Weibel-Palade bodies (WPBs). When ADAMTS13 activity falters, undegraded ULVWF complexes with platelets to spawn microthrombi, precipitating microvascular occlusion and multiorgan collapse. Strikingly, elevated plasma von Willebrand factor (vWF) antigen levels in sepsis patients correlate robustly with endothelial injury, thrombocytopenia, and mortality-underscoring C5b-9-driven vWF release as a linchpin of septic coagulopathy. Current therapeutic strategies targeting these pathways, including recombinant ADAMTS13 (rhADAMTS13), N-acetylcysteine (NAC), and complement inhibitors like eculizumab, face limitations in clinical translation, necessitating further validation of their efficacy. Additionally, investigating complement regulatory molecules such as CD59 may unlock novel therapeutic avenues. Deciphering the intricate interplay within the C5b-9-vWF axis and advancing precision therapies hold transformative potential for ameliorating sepsis outcomes.

The current array of traditional antibacterial agents targeting Gram-negative infections are failing to meet the clinical need. Here we present a novel, bifunctional immunotherapy (CTX-09) with the ability to harness endogenous anti-galactose-alpha-1,3-galactosyl-beta-1,4-N-acetyl-glucosamine (anti-αGal) antibodies to drive immune-mediated clearance of Gram-negative bacteria. In addition, CTX-09 has direct-acting broad-spectrum bactericidal activity equivalent to colistin and meropenem against 1952 Gram-negative clinical isolates. In vitro, CTX-09 demonstrated immune-mediated efficacy through recruitment of anti-αGal antibodies and engagement of antibody effector mechanisms that enhanced bacterial clearance at sub-bactericidal concentrations. In vivo, at sub-bactericidal doses, CTX-09 demonstrated anti-αGal antibody driven clearance of susceptible and multidrug-resistant (MDR) strains. In the presence of anti-αGal antibody, bacterial burden was reduced by >99.9% (3-log10) in neutropenic mouse thigh and pneumonia infection models. This data suggest that CTX-09 or other antibody-recruiting molecules have potential to address the urgent clinical need of patients with gram-negative infections using a novel immunotherapeutic mechanism.

Sterile tissue injury is accompanied by an acute inflammatory response whereby innate immune cells rapidly migrate to the site of injury guided by pro-inflammatory chemotactic damage signals released at the wound. Understanding this immune response is key to improving human health, and recent advances in imaging technology have allowed researchers using different model organisms to observe this inflammatory response in vivo. Over recent decades, offering a unique combination of live time-lapse microscopy and genetics, the fruit fly Drosophila has emerged as a powerful model system to study inflammatory cell migration within a living animal.1,2,3,4 However, we still know relatively little regarding the identity of the earliest signals that drive this immune cell recruitment and the mechanisms by which they act within the complex, in vivo setting of a multicellular organism. Here, we couple the powerful genetics and live imaging of Drosophila with mathematical modeling to identify the fly complement ortholog-macroglobulin complement-related (Mcr)-as an early, wound-induced chemotactic signal responsible for the inflammatory recruitment of immune cells to injury sites in vivo. We show that epithelial-specific knockdown of Mcr suppresses the recruitment of macrophages to wounds and combine predictive mathematical modeling with in vivo genetics to understand macrophage migration dynamics following manipulation of this chemoattractant. We propose a model whereby Mcr operates alongside hydrogen peroxide to ensure a rapid and efficient immune response to damage, uncovering a novel function for this protein that parallels the chemotactic role of the complement component C5a in mammals.

Horseshoe bats are natural hosts of zoonotic viruses, yet the genetic basis of their antiviral immunity is poorly understood. Here we generated two new chromosomal-level genome assemblies for horseshoe bat species (Rhinolophus) and three close relatives, and show that, during their diversification, horseshoe bats underwent extensive chromosomal rearrangements and gene expansions linked to segmental duplications. These expansions have generated new adaptive variations in type I interferons and the interferon-stimulated gene ANXA2R, which potentially enhance antiviral states, as suggested by our functional assays. Genome-wide selection screens, including of candidate introgressed regions, uncover numerous putative molecular adaptations linked to immunity, including in viral receptors. By expanding taxon coverage to ten horseshoe bat species, we identify new variants of the SARS-CoV-2 receptor ACE2, and report convergent functionally important residues that could explain wider patterns of susceptibility across mammals. We conclude that horseshoe bats have numerous signatures of adaptation, including some potentially related to immune response to viruses, in genomic regions with diverse and multiscale mutational changes.

Aortic disease encompasses life-threatening conditions such as aortic aneurysm and dissection, which are associated with high prevalence, morbidity, and mortality. The complement system, a key component of innate immunity, not only defends against pathogens but also maintains tissue homeostasis. Recent discoveries have expanded its role beyond immunity, linking complement dysregulation to numerous diseases and positioning it as a target for pharmacotherapy. Complement-based treatments for precision medicine are emerging, with several pharmaceuticals either already approved or under investigation. In aortic disease, complement activation and dysregulation have unveiled novel mechanisms and clinical implications. Human and experimental studies suggest that all three complement pathways contribute to disease pathophysiology. The complement system induces direct cellular damage via the membrane attack complex, as well as matrix-metalloproteinase (MMP)-associated tissue damage by promoting MMP-2 and MMP-9 expression. The anaphylatoxins C3a and C5a exacerbate disease by recruiting immune cells and triggering proinflammatory responses. Examples include neutrophil extracellular trap formation and cytokine release by polymorphonuclear neutrophils. These findings highlight the complement system as a promising novel diagnostic and therapeutic target in aortic disease with potential for individualized treatment. However, gaps remain, emphasizing the need for standardized multisite preclinical studies to improve reproducibility and translation. Biomarker studies must also be validated across diverse patient cohorts for clinical applicability. This review examines current knowledge regarding complement in aortic disease, aiming to evaluate its potential for innovative diagnostic and personalized treatment strategies.

Sepsis is a complex syndrome resulting from an aberrant host response to infection. A hallmark of sepsis is the failure of the immune system to restore balance, characterized by hyperinflammation or immunosuppression. However, the net effect of immune system imbalance and the clinical manifestations are highly heterogeneous among patients. In recent years, research interest has shifted from focusing on the pathogenicity of microorganisms to the molecular mechanisms of host responses which is also associated with biomarkers that can help early diagnose sepsis and guide treatment decisions. Despite significant advancements in medical science, sepsis remains a major challenge in healthcare, contributing to substantial morbidity and mortality worldwide. Further research is needed to improve our understanding of this condition and develop novel therapies to improve outcomes for patients with sepsis. This review explores the related signal pathways of sepsis and underscores recent advancements in understanding its mechanisms. Exploration of diverse biomarkers and the emerging concept of sepsis endotypes offer promising avenues for precision therapy in the future.

Mycoplasma pneumoniae is an important human respiratory pathogen that causes mild-to-moderate community-acquired M. pneumoniae pneumonia (MPP), particularly in children. RNA editing plays a vital role in pathogen infection and host immune response, but it remains largely unknown how it could be involved in the epigenetic regulation of host response to M. pneumoniae infection. In the present study, we performed an epitranscriptomic analysis of adenosine to inosine (A-to-I) editing in 39 bronchoalveolar lavage fluid (BALF) samples from the severe side (SS) and the opposite side (OS) of patients with MPP. Our editome profiling identified 87 differential RNA editing (DRE) events in 50 genes, especially missense editing events that recoded C-C motif chemokine receptor-like 2 (CCRL2, p.K147R) and cyclin I (CCNI, p.R75G). The expression of adenosine deaminase acting on RNA (ADAR) significantly increased on SS compared to OS and positively correlated with the average RNA editing level and individual DRE events. Meanwhile, functional enrichment analysis showed that DRE was observed in genes primarily associated with the negative regulation of innate immune response, type I interferon production, and cytokine production. Further comparison of SS between complicated MPP (CMPP) and non-complicated MPP (NCMPP) revealed RNA editing events associated with MPP complications, with a higher ADAR expression in CMPP than NCMPP. By identifying DRE events as biomarkers associated with MPP severity and complications, our editome profiling provides new insight into the potential role played by A-to-I RNA editing in modulating the host's immune system during M. pneumoniae infection.IMPORTANCEOur research investigates how Mycoplasma pneumoniae, a common respiratory pathogen, influences how our cells modify their genetic instructions. By studying RNA editing changes in bronchoalveolar lavage fluid from patients with M. pneumoniae pneumonia, we aim to investigate how M. pneumoniae infection alters epigenetics and contributes to the disease severity and complications. Understanding such epigenetic alterations not only sheds light on the mechanisms underlying M. pneumoniae infection but also holds potential implications for developing better diagnostic tools and therapies. Ultimately, this work may facilitate the design of more targeted treatments to alleviate the impact of respiratory infections caused by the pathogen. Our findings may also offer broader insights into how microbial infections reshape immune processes, highlighting the importance of RNA editing in host-pathogen interactions.

The pandemic potential of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) highlights the critical need for effective vaccines due to its high fatality rate of around 36%. In this review, we identified a variety of immunotherapeutic molecules and diagnostic biomarkers that could be used in MERS vaccine development as human-derived adjuvants. We identified immune molecules that have been incorporated into standard clinical diagnostics such as CXCL10/IP10, CXCL8/IL-8, CCL5/RANTES, IL-6, and the complement proteins Ca3 and Ca5. Utilization of different human monoclonal antibodies in the treatment of MERS-CoV patients demonstrates promising outcomes in combatting MERS-CoV infections in vivo, such as hMS-1, 4C2H, 3B11-N, NBMS10-FC, HR2P-M2, SAB-301, M336, LCA60, REGN3051, REGN3048, MCA1, MERs-4, MERs-27, MERs-gd27, and MERs-gd33. Host-derived adjuvants such as CCL28, CCL27, RANTES, TCA3, and GM-CSF have shown significant improvements in immune responses, underscoring their potential to bolster both systemic and mucosal immunity. In conclusion, we believe that host-derived adjuvants like HBD-2, CD40L, and LL-37 offer significant advantages over synthetic options in vaccine development, underscoring the need for clinical trials to validate their efficacy.

The role of the complement system in pain syndromes has garnered attention on the back of preclinical and clinical evidence supporting its potential as a target for new analgesic pharmacotherapies. Of the components that make up the complement system, component 5a (C5a) and component 3a (C3a) are most strongly and consistently associated with pain. Receptors for C5a are widely found in immune resident cells (microglia, astrocytes, sensory neuron-associated macrophages (sNAMs)) in the central nervous system (CNS) as well as hematogenous immune cells (mast cells, macrophages, T-lymphocytes, etc.). When active, as is often observed in chronic pain conditions, these cells produce various inflammatory mediators including pro-inflammatory cytokines. These events can trigger nervous tissue inflammation (neuroinflammation) which coexists with and potentially maintains peripheral and central sensitization. C5a has a likely critical role in initiating this process highlighting its potential as a promising non-opioid target for treating pain. This review summarizes the most up-to-date research on the role of the complement system in pain with emphasis on the C5 pathway in peripheral tissue, dorsal root ganglia (DRG) and the CNS, and explores advances in complement-targeted drug development and sex differences. A perspective on the optimal application of different C5a inhibitors for different types (e.g., neuropathic, post-surgical and chemotherapy-induced pain, osteoarthritis pain) and stages (e.g., acute, subacute, chronic) of pain is also provided to help guide future clinical trials. PERSPECTIVE: This review highlights the role and mechanisms of complement components and their receptors in physiological and pathological pain. The potential of complement-targeted therapeutics for the treatment of chronic pain is also explored with a focus on C5a inhibitors to help guide future clinical trials.

Acute pancreatitis (AP) is one of the most common gastrointestinal emergencies, often resulting in self-digestion, edema, hemorrhage, and even necrosis of pancreatic tissue. When AP progresses to severe acute pancreatitis (SAP), it often causes multi-organ damage, leading to a high mortality rate. However, the molecular mechanisms underlying SAP-mediated organ damage remain unclear. This study aims to systematically mine SAP data from public databases and combine experimental validation to identify key molecules involved in multi-organ damage caused by SAP. Retrieve transcriptomic data of mice pancreatic tissue for AP, lung and liver tissue for SAP, and corresponding normal tissue from the Gene Expression Omnibus (GEO) database. Conduct gene differential analysis using Limma and DEseq2 methods. Perform enrichment analysis using the clusterProfiler package in R software. Score immune cells and immune status in various organs using single-sample gene set enrichment analysis (ssGSEA). Evaluate mRNA expression levels of core genes using reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. Validate serum amylase, TNF-α, IL-1β, and IL-6 levels in peripheral blood using enzyme-linked immunosorbent assay (ELISA), and detect the formation of neutrophil extracellular traps (NETs) in mice pancreatic, liver, and lung tissues using immunofluorescence. Differential analysis reveals that 46 genes exhibit expression dysregulation in mice pancreatic tissue for AP, liver and lung tissue for SAP, as well as peripheral blood in humans. Functional enrichment analysis indicates that these genes are primarily associated with neutrophil-related biological processes. ROC curve analysis indicates that 12 neutrophil-related genes have diagnostic potential for SAP. Immune infiltration analysis reveals high neutrophil infiltration in various organs affected by SAP. Single-cell sequencing analysis shows that these genes are predominantly expressed in neutrophils and macrophages. FPR1, ITGAM, and C5AR1 are identified as key genes involved in the formation of NETs and activation of neutrophils. qPCR and IHC results demonstrate upregulation of FPR1, ITGAM, and C5AR1 expression in pancreatic, liver, and lung tissues of mice with SAP. Immunofluorescence staining shows increased levels of neutrophils and NETs in SAP mice. Inhibition of NETs formation can alleviate the severity of SAP as well as the levels of inflammation in the liver and lung tissues. This study identified key genes involved in the formation of NETs, namely FPR1, ITGAM, and C5AR1, which are upregulated during multi-organ damage in SAP. Inhibition of NETs release effectively reduces the systemic inflammatory response and liver-lung damage in SAP. This research provides new therapeutic targets for the multi-organ damage associated with SAP.

Methotrexate (MTX) is an antimetabolite drug that mimics folate and inhibits dihydrofolic acid reductase, resulting in the impairment of malignant growth in actively proliferating tissues. MTX is approved by the FDA for primarily treating non-Hodgkin lymphoma, lymphoblastic leukemia, and osteosarcoma. In addition, MTX is also prescribed as a preferred anti-rheumatic medication for the management of rheumatoid arthritis, including psoriasis, indicating that MTX has a multipronged mechanism of action. MTX is also known to exert anti-inflammatory effects, and interestingly, the role of C5a, a pro-inflammatory glycoprotein of the complement system, is well established in several chronic inflammatory diseases, including rheumatoid arthritis and psoriasis, through the recruitment of C5a receptors (C5aR1/C5aR2) expressed in both immune and non-immune cells. Notably, through drug repurposing studies, we have earlier shown that non-steroidal anti-inflammatory drugs (NSAIDS) can potentially neutralize the function of C5a. Though MTX binds to serum albumin and can affect the immune system, whether its interaction with C5a could be therapeutically beneficial due to the downregulation of both extracellular and intracellular signaling of C5a is not yet established in the literature. In the current study, we have hypothesized and provided preliminary evidence through computational studies that MTX can strongly bind to the hotspot regions on C5a involved in the interactions with its receptors, which is likely to alter the downstream signaling of C5a and contribute to the overall therapeutic efficacy of MTX.

The complement system includes soluble and cell surface proteins and is an important arm of the innate immune system. Once activated, the complement system rapidly generates proteins with inflammatory and vasoactive activities. Although complement is crucial to host defense and homeostasis, its inappropriate or uncontrolled activation can also drive tissue injury. Glomerulopathy encompasses a spectrum of diseases with diverse etiologies, clinical presentations, and outcomes. Among the intricate web of factors contributing to glomerulopathies pathogenesis, the role of complement activation has emerged as a focal point of research interest and therapeutic intervention. The pioneer drug was eculizumab, which made it possible to drastically change the prognosis of atypical hemolytic uremic syndrome, an otherwise fatal disease. This comprehensive review aims to elucidate the multifaceted interplay between complement pathways and glomerulopathies, shedding light on potential pathways for targeted therapies and improved patient care.

Severe sepsis is cognate with life threatening multi-organ dysfunction. There is a disturbance in endocrine functions with alterations in several hormonal pathways. It has frequently been linked with dysfunction in the hypothalamic pituitary-adrenal axis (HPA). Increased cortisol or cortisolemia is evident throughout the acute phase, along with changes in the hypothalamic pituitary thyroid (HPT) axis, growth hormone-IGF-1 axis, insulin-glucose axis, leptin, catecholamines, renin angiotensin aldosterone axis, ghrelin, glucagon, hypothalamic pituitary gonadal (HGA) axis, and fibroblast growth factor-21. These changes and metabolic alterations constitute the overall response to infection in sepsis. Further research is essential to look into the hormonal changes that occur during sepsis, not only to understand their potential relevance in therapy but also because they may serve as prognostic indicators.

Ischemic stroke (IS) is the most prevalent type of cerebrovascular disease. Taohong Siwu Decoction (THSWD) has been demonstrated to have neuroprotective benefits during Cerebral Ischemia-Reperfusion Injury (CIRI). Whether THSWD mitigates CIRI by modulating the circDnajc1/miR-27a-5p/C1qc signaling axis is not known.

Examine how THSWD provides neuroprotective benefits in reducing the damage wrought by IS.

We employed middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and oxygen glucose deprivation/re-oxygenation (OGD/R) in vitro model. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot (WB), and immunofluorescence analyses (IF) were utilized to detect microglial activation markers TMEM119, CD11b, and Iba1, inflammatory mediators CCL2, CCL6, IL1, IL6, IL10, and TNF-α, as well as circDnajc1, miR-27a-5p, C1qc, C3, and C5aR.

Our data suggest that THSWD can mitigate inflammatory response, inhibit microglial activation and neuron apoptosis, and exert neuroprotective effects by regulating the circDnajc1/miR-27a-5p/C1qc signaling axis.

The complement system is implicated in various facets of kidney transplantation, including ischemia-reperfusion injury (IRI), delayed graft function, allograft rejection, and chronic allograft injury. IRI, prevalent in cadaveric renal transplantation, leads to acute tubular necrosis and engages innate immunity, including neutrophils and the complement system, fostering a cycle of inflammation and necrosis. Experimental and preclinical evidence suggest that targeting the complement system could offer therapeutic benefits in IRI during kidney transplantation. This article explores potential therapeutic approaches targeting complement pathways in kidney transplantation, drawing from experimental and preclinical research findings.

Current guidelines tend to focus on a p-value threshold of a pre-specified primary endpoint tested in randomized controlled clinical trials to determine a treatment effect for a specific drug. However, a p-value does not always provide evidence on the treatment effect of a drug, especially when stratification of the data does not account for unforeseen variables introduced into the analysis. We report and discuss a rare case in which investigational site stratification in the pre-specified analysis method of a primary endpoint results in a loss of statistical power in the evaluation of the treatment effect due to data attrition of almost 17% of outcome data in the phase III randomized, controlled PANAMO study in critically ill COVID-19 patients. Other analyses utilizing no or different stratification (e.g., stratifying by country, region, pooling low enrollment clinical sites) evaluates 100% of patient data resulting in p-values suggesting a positive treatment effect (p < 0.05). We demonstrate how this technical artifact occurs by adjustment for site stratification within the Cox regression analysis for survival outcomes and how alternative stratification corrects this discrepancy.

Neutrophils, the most abundant type of granulocyte, are widely recognized as one of the pivotal contributors to the acute inflammatory response. Initially, neutrophils were considered the mobile infantry of the innate immune system, tasked with the immediate response to invading pathogens. However, recent studies have demonstrated that neutrophils are versatile cells, capable of regulating various biological processes and impacting both human health and disease. Cytokines and other active mediators regulate the functional activity of neutrophils by activating multiple receptors on these cells, thereby initiating downstream signal transduction pathways. Dysfunctions in neutrophils and disruptions in neutrophil homeostasis have been implicated in the pathogenesis of numerous diseases, including cancer and inflammatory disorders, often due to aberrant intracellular signaling. This review provides a comprehensive synthesis of neutrophil biological functions, integrating recent advancements in this field. Moreover, it examines the biological roles of receptors on neutrophils and downstream signaling pathways involved in the regulation of neutrophil activity. The pathophysiology of neutrophils in numerous human diseases and emerging therapeutic approaches targeting them are also elaborated. This review also addresses the current limitations within the field of neutrophil research, highlighting critical gaps in knowledge that warrant further investigation. In summary, this review seeks to establish a comprehensive and multidimensional model of neutrophil regulation, providing new perspectives for potential clinical applications and further research.

Considerable advances have been achieved in the application of nanomaterials for immunotherapies, yet the precise immune effects induced by protein corona remain elusive. Here, we explore the formation mechanism and immune regulation process of protein corona in acute myeloid leukaemia (AML) mouse models using commercialized iron oxide nanoparticles (IONPs), with different surface modifications, including an FDA-approved variant. Using macrophages depleted or Complement Component 3 (C3) knockout mice, we demonstrate that carboxymethyl dextran-coated IONP (IONP-COOH) reduces leukaemia burden. Mechanistically, IONP-COOH indirectly binds to C3b after activating the complement alternative pathway, subsequently enhancing phagocytosis of macrophages and activating adaptive immunity mediated by complement corona. While aminated dextran-coated IONPs directly absorb C3b and activate the lectin pathway, leading to immune cell exhaustion. Our findings suggest that IONP-COOH may serve as an immune activator for AML treatment, offering a promising approach to developing therapeutic nanomaterials by leveraging surface chemistry to enhance immunotherapy.

Chemerin is a chemotactic adipokine that participates in a multitude of physiological processes, including adipogenesis, leukocyte chemotaxis, and neuroinflammation. Chemerin exerts biological functions through binding to one or more of its G protein-coupled receptors (GPCRs), namely chemokine-like receptor 1 (CMKLR1), G protein-coupled receptor 1 (GPR1), and CC-motif receptor-like 2 (CCRL2). Of these receptors, CMKLR1 and GPR1 have been confirmed as signaling receptors of chemerin, whereas CCRL2 serves as a chemerin-binding protein without transmembrane signaling. High-resolution structures of two chemerin receptors are now available thanks to recent advancements in structure biology. This review focuses on the structural perspectives of the chemerin receptors with an emphasis on the structure-activity correlation, including key components of the two receptors for ligand recognition and conformational changes induced by chemerin and its derivative peptides for G protein activation. There are also comparisons between the two chemerin receptors and selected GPCRs with peptide ligands for better appreciation of the shared and distinct features of the chemerin receptors in ligand recognition and transmembrane signaling, and in the evolution of this subclass of GPCRs.

Complement C5a protein has been shown to play a major role in tissue regeneration through interaction with its receptor (C5aR) on target cells. Expression of this receptor has been reported in the nervous system which, upon injury, has no treatment to restore the lost functions. This work aimed at investigating the Complement C5a effect on axonal growth after axotomy in vitro. Primary hippocampal neurons were isolated from embryonic Wistar rats. Cell expression of C5aR mRNA was verified by RT-PCR while its membrane expression, localization, and phosphorylation were investigated by immunofluorescence. Then, the effects of C5a on injured axonal growth were investigated using a 3D-printed microfluidic device. Immunofluorescence demonstrated that the primary cultures contained only mature neurons (93%) and astrocytes (7%), but no oligodendrocytes or immature neurons. Immunofluorescence revealed a co-localization of NF-L and C5aR only in the mature neurons where C5a induced the phosphorylation of its receptor. C5a application on injured axons in the microfluidic devices significantly increased both the axonal growth speed and length. Our findings highlight a new role of C5a in regeneration demonstrating an enhancement of axonal growth after axotomy. This may provide a future therapeutic tool in the treatment of central nervous system injury.

Microtus fortis is known as a non-susceptible animal host of S. japonicum. A better understanding of this animal immune defense mechanism during the early stage of infection may offer an alternative route for vaccine development or therapy. Here, we analyzed the whole blood transcriptome of M. fortis using next-generation sequencing (NGS) to identify immune genes of biological relevance that might be involved in the mechanism of its resistance. The blood samples were collected from uninfected animals (control group) and infected animals at different time points (3, 7, 10 and 14 days post-infection). We identified 5310 sequences as unigenes and successfully annotated 4636 of them. The immune response was more intense at 10 dpi. The upregulated genes at this time point were mainly activated in the TNF and NF-kappa B signaling pathways, Th1, Th2and Th17 cell differentiation as well as cytokine-cytokine receptor interaction. Based on the differentially expressed genes analysis, we report that the IF27L2B, RETN, PGRP, IFI35, TYROBP, S100A8, S100A11, CD162, CD88, CYBA, and LBP could play important roles in the mechanism of M. fortis resistance.

The prevailing paradigm posits orthodontic tooth movement (OTM) as primarily a localized inflammatory process. In this study, we endeavor to elucidate the potential ramifications of mechanical force on systemic immunity, employing a time-dependent approach.

A previously described mouse orthodontic model was used. Ni-Ti. springs were set to move the upper 1st-molar in C57BL/6 mice and the amount of OTM was. measured by µCT. Mice were allocated randomly into four experimental groups, each. corresponding to clinical phases of OTM, relative to force application. Terminal blood. samples were collected and a comprehensive blood count test for 7 cell types as well as. proteome profiling of 111 pivotal cytokines and chemokines were conducted. Two controls. groups were included: one comprised non-treated mice and the other mice with inactivated springs.

Serum immuno-profiling unveiled alterations in cellular immunity, manifesting as. changes in percentages of leukocytes, monocytes, macrophages, neutrophils, and. lymphocytes, alongside key signaling factors in comparison to both control groups. The systemic cellular and molecular alterations triggered by OTM mirrored the dynamics previously described in the local immune response.

Although the exact interplay between local and systemic immune responses to orthodontic forces require further elucidation, our findings demonstrate a tangible link between the two. Future investigations should aim to correlate these results with human subjects, and strive to delve deeper into the specific mechanisms by which mechanical force modulates the systemic immune response.

Oral neomycin administration impacts the gut microbiome and delays vitiligo development in mice, and topical antibiotics may likewise allow the microbiome to preserve skin health and delay depigmentation. Here, we examined the effects of 6-week topical antibiotic treatment on vitiligo-prone pmel-1 mice. Bacitracin, Neosporin, or Vaseline were applied to one denuded flank, while the contralateral flank was treated with Vaseline in all mice. Ventral depigmentation was quantified weekly. We found that topical Neosporin treatment significantly reduced depigmentation and exhibited effects beyond the treated area, while Bacitracin ointment had no effect. Stool samples collected from four representative mice/group during treatment revealed that Neosporin treatment aligned with reduced abundance of the Alistipes genus in the gut, while relevant changes to the skin microbiome at end point were less apparent. Either antibiotic treatment led to reduced expression of MR1, potentially limiting mucosal-associated invariant T-cell activation, while Neosporin-treated skin selectively revealed significantly reduced CD8+ T-cell abundance. The latter finding aligned with reduced expression of multiple inflammatory markers and markedly increased regulatory T-cell density. Our studies on favorable skin and oral antibiotic treatment share the neomycin compound, and in either case, microbial changes were most apparent in stool samples. Taken together, neomycin-containing antibiotic applications can mediate skin Treg infiltration to limit vitiligo development. Our study highlights the therapeutic potential of short-term antibiotic applications to limit depigmentation vitiligo.

Previous studies indicate an implication of the terminal complement complex (TCC) in disc degeneration (DD). To investigate the functional role of TCC in trauma-induced DD in vivo, the model of endplate (EP) drilling was first applied in rabbits using a C6-deficient rabbit strain in which no TCC formation was possible. In parallel the model of needle puncture was investigated. Using a minimally invasive surgical intervention, lumbar rabbit intervertebral discs (IVDs) were treated with EP drilling or needle puncture. Degenerative effects of both surgical interventions were assessed by Pfirrmann grading and T2 quantification of the IVDs based on high-resolution MRI (11.7 T), as well as radiographic determination of disc height index. Pfirrmann grading indicated significant degenerative effects after EP drilling. Contrary to our assumption, no evidence was found that the absence of TCC formation in C6-deficient rabbits reduces the development of DD compared to C6-sufficient animals. EP drilling was proven to be suitable for application in rabbits. However, results of the present study do not provide clear evidence of a central functional role of TCC within DD and suggest that TCC deposition in DD patients may be primarily considered as a marker of complement activation during DD progression.

Chronic wounds pose a significant clinical challenge due to their complex pathophysiology and the burden of long-term management. Monoclonal antibodies (mAbs) are emerging as a novel therapeutic option in managing difficult wounds, although comprehensive data on their use in wound care are lacking. This study aimed to explore existing scientific knowledge of mAbs in treating chronic wounds based on a rationale of direct inhibition of the main molecules involved in the underlying inflammatory pathophysiology. We performed a literature review excluding primary inflammatory conditions with potential ulcerative outcomes (e.g., hidradenitis suppurativa). mAbs were effective in treating wounds from 16 different etiologies. The most commonly treated conditions were pyoderma gangrenosum (treated with 12 different mAbs), lipoid necrobiosis, and cutaneous vasculitis (each treated with 3 different mAbs). Fourteen mAbs were analyzed in total. Rituximab was effective in 43.75% of cases (7/16 diseases), followed by tocilizumab (25%, 4/16 diseases), and both etanercept and adalimumab (18.75%, 3/16 conditions each). mAbs offer therapeutic potential for chronic wounds unresponsive to standard treatments. However, due to the complex molecular nature of wound healing, no single target molecule can be identified. Therefore, the use of mAbs should be considered as a translational approach for limited cases of multi-resistant conditions.

Sepsis poses a significant threat to human health due to its high morbidity and mortality rates worldwide. Traditional diagnostic methods for identifying sepsis or its causative organisms are time-consuming and contribute to a high mortality rate. Biomarkers have been developed to overcome these limitations and are currently used for sepsis diagnosis, prognosis prediction, and treatment response assessment. Over the past few decades, more than 250 biomarkers have been identified, a few of which have been used in clinical decision-making. Consistent with the limitations of diagnosing sepsis, there is currently no specific treatment for sepsis. Currently, the general treatment for sepsis is conservative and includes timely antibiotic use and hemodynamic support. When planning sepsis-specific treatment, it is important to select the most suitable patient, considering the heterogeneous nature of sepsis. This comprehensive review summarizes current and evolving biomarkers and therapeutic approaches for sepsis.

The complement system, an upstream recognition system of innate immunity, is activated upon SARS-CoV-2 infection. To gain a deeper understanding of the extent and duration of this activation, we investigated complement activation profiles during the acute phase of COVID-19, its persistence post-recovery and dynamic changes in relation to disease severity.

Serial blood samples were obtained from two cohorts of hospitalized COVID-19 patients (n = 457). Systemic complement activation products reflecting classical/lectin (C4d), alternative (C3bBbP), common (C3bc) and terminal pathway (TCC and C5a) were measured during hospitalization (admission, days 3-5 and days 7-10), at 3 months and after 1 year. Levels of activation and temporal profiles during hospitalization were related to disease severity defined as respiratory failure (PO2/FiO2 ratio <26.6 kPa) and/or admission to intensive care unit, 60-day total mortality and pulmonary pathology after 3 months.

During hospitalization, TCC, C4d, C3bc, C3bBbP and C5a were significantly elevated compared to healthy controls. Severely ill patients had significantly higher levels of TCC and C4d (p < 0.001), compared to patients with moderate COVID-19. Escalated levels of TCC and C4d during hospitalization were associated with a higher risk of 60-day mortality (p < 0.001), and C4d levels were additionally associated with chest CT changes at 3 months (p < 0.001). At 3 months and 1 year, we observed consistently elevated levels of most complement activation products compared to controls.

Hospitalized COVID-19 patients display prominent and long-lasting systemic complement activation. Optimal targeting of the system may be achieved through enhanced risk stratification and closer monitoring of in-hospital changes of complement activation products.

Innovative therapies against bacterial infections are needed. One approach is to focus on host-directed immunotherapy (HDT), with treatments that exploit natural processes of the host immune system. The goals of this type of therapy are to stimulate protective immunity while minimizing inflammation-induced tissue damage. We use non-traditional large animal models to explore the potential of the mammosphere-derived epithelial cell (MDEC) secretome, consisting of all bioactive factors released by the cells, to modulate host immune functions. MDEC cultures are enriched for mammary stem and progenitor cells and can be generated from virtually any mammal. We previously demonstrated that the bovine MDEC secretome, collected and delivered as conditioned medium (CM), inhibits the growth of bacteria in vitro and stimulates functions related to tissue repair in cultured endothelial and epithelial cells.

The immunomodulatory effects of the bovine MDEC secretome on bovine neutrophils, an innate immune cell type critical for resolving bacterial infections, were determined in vitro using functional assays. The effects of MDEC CM on neutrophil molecular pathways were explored by evaluating the production of specific cytokines by neutrophils and examining global gene expression patterns in MDEC CM-treated neutrophils. Enzyme linked immunosorbent assays were used to determine the concentrations of select proteins in MDEC CM and siRNAs were used to reduce the expression of specific MDEC-secreted proteins, allowing for the identification of bioactive factors modulating neutrophil functions.

Neutrophils exposed to MDEC secretome exhibited increased chemotaxis and phagocytosis and decreased intracellular reactive oxygen species and extracellular trap formation, when compared to neutrophils exposed to control medium. C-X-C motif chemokine 6, superoxide dismutase, peroxiredoxin-2, and catalase, each present in the bovine MDEC secretome, were found to modulate neutrophil functions.

The MDEC secretome administered to treat bacterial infections may increase neutrophil recruitment to the site of infection, stimulate pathogen phagocytosis by neutrophils, and reduce neutrophil-produced ROS accumulation. As a result, pathogen clearance might be improved and local inflammation and tissue damage reduced.

Atopic dermatitis, psoriasis and lichen sclerosus are among the most challenging conditions treated by dermatologists worldwide, with potentially significant physical, social and psychological impacts. Emerging evidence suggests that autologous-platelet-rich plasma could be used to manage skin inflammation. However, the presence of soluble autoimmune components could hinder their therapeutic potential. The aim of this study was to analyze the proteomic profile of plasma rich in growth factors (PRGFs) obtained from donors with inflammatory skin conditions to evaluate the impact of skin health status on the composition and bioactivity of PRGF-based treatments. Venous blood from healthy volunteers and patients with psoriasis, lichen sclerosus and atopic dermatitis was processed to produce PRGF supernatant. Half of the samples were subjected to an additional thermal treatment (56 °C) to inactivate inflammatory and immune molecules. Proteomic analysis was performed to assess the protein profile of PRGFs from healthy and non-healthy patients and the effect of Immunosafe treatment. Differential abundance patterns of several proteins related to key biological processes have been identified, including complement activation, blood coagulation, and glycolysis- and gluconeogenesis-related genes. These results also demonstrate that the thermal treatment (Immunosafe) contributes to the inactivation of the complement system and, as a consequence, reduction in the immunogenic potential of PRGF products.

Affinity reagents, or target-binding molecules, are quite versatile and are major workhorses in molecular biology and medicine. Antibodies are the most famous and frequently used type and they have been used for a wide range of applications, including laboratory techniques, diagnostics, and therapeutics. However, antibodies are not the only available affinity reagents and they do have significant drawbacks, including laborious and costly production. Aptamers are one potential alternative that have a variety of unique advantages. They are single stranded DNA or RNA molecules that can be selected for binding to many targets including proteins, carbohydrates, and small molecules-for which antibodies typically have low affinity. There are also a variety of cost-effective methods for producing and modifying nucleic acids in vitro without cells, whereas antibodies typically require cells or even whole animals. While there are also significant drawbacks to using aptamers in therapeutic applications, including low in vivo stability, aptamers have had success in clinical trials for treating a variety of diseases and two aptamer-based drugs have gained FDA approval. Aptamer development is still ongoing, which could lead to additional applications of aptamer therapeutics, including antitoxins, and combinatorial approaches with nanoparticles and other nucleic acid therapeutics that could improve efficacy.

The classical pathway of the complement system is activated by the binding of C1q in the C1 complex to the target activator, including immune complexes. Factor H is regarded as the key downregulatory protein of the complement alternative pathway. However, both C1q and factor H bind to target surfaces via charge distribution patterns. For a few targets, C1q and factor H compete for binding to common or overlapping sites. Factor H, therefore, can effectively regulate the classical pathway activation through such targets, in addition to its previously characterized role in the alternative pathway. Both C1q and factor H are known to recognize foreign or altered-self materials, e.g., bacteria, viruses, and apoptotic/necrotic cells. Clots, formed by the coagulation system, are an example of altered self. Factor H is present abundantly in platelets and is a well-known substrate for FXIIIa. Here, we investigated whether clots activate the complement classical pathway and whether this is regulated by factor H. We show here that both C1q and factor H bind to the fibrin formed in microtiter plates and the fibrin clots formed under in vitro physiological conditions. Both C1q and factor H become covalently bound to fibrin clots, and this is mediated via FXIIIa. We also show that fibrin clots activate the classical pathway of complement, as demonstrated by C4 consumption and membrane attack complex detection assays. Thus, factor H downregulates the activation of the classical pathway induced by fibrin clots. These results elucidate the intricate molecular mechanisms through which the complement and coagulation pathways intersect and have regulatory consequences.

The present study aimed to use detailed phenotyping for the claw disorder digital dermatitis (DD) considering specific DD stages in 2 housing systems (conventional cubicle barns [CON] and compost-bedded pack barns [CBPB]) to infer possible genotype × housing system interactions. The DD stages included 2,980 observations for the 3 traits DD-sick, DD-acute, and DD-chronic from 1,311 Holstein-Friesian and 399 Fleckvieh-Simmental cows. Selection of the 5 CBPB and 5 CON herds was based on a specific protocol to achieve a high level of herd similarity with regard to climate, feeding, milking system, and location, but with pronounced housing-system differences. Five other farms had a "mixed system" with 2 subherds, one representing CBPB and the other one CON. The CBPB system was represented by 899 cows (1,530 observations), and 811 cows (1,450 observations) represented the CON system. The average disease prevalence was 20.47% for DD-sick, 13.88% for DD-acute, and 5.34% for DD-chronic, with a higher prevalence in CON than in CBPB. After quality control of 50K genotypes, 38,495 SNPs from 926 cows remained for the ongoing genomic analyses. Genetic parameters for DD-sick, DD-acute, and DD-chronic were estimated by applying single-step approaches for single-trait repeatability animal models considering the whole dataset, and separately for the CON and CBPB subsets. Genetic correlations between same DD traits from different housing systems, and between DD-sick, DD-chronic, and DD-acute, were estimated via bivariate animal models. Heritabilities based on the whole dataset were 0.16 for DD-sick, 0.14 for DD-acute, and 0.11 for DD-chronic. A slight increase of heritabilities and genetic variances was observed in CON compared with the "well-being" CBPB system, indicating a stronger genetic differentiation of diseases in a more challenging environment. Genetic correlations between same DD traits recorded in CON or CBPB were close to 0.80, disproving obvious genotype × housing system interactions. Genetic correlations among DD-sick, DD-acute and DD-chronic ranged from 0.58 to 0.81. SNP main effects and SNP × housing system interaction effects were estimated simultaneously via GWAS, considering only the phenotypes from genotyped cows. Ongoing annotations of potential candidate genes focused on chromosomal segments 100 kb upstream and downstream from the significantly associated candidate SNP. GWAS for main effects indicated heterogeneous Manhattan plots especially for DD-acute and DD-chronic, indicating particularities in disease pathogenesis. Nevertheless, a few shared annotated potential candidate genes, that is, METTL25, AFF3, PRKG1, and TENM4 for DD-sick and DD-acute, were identified. These genes have direct or indirect effects on disease resistance or immunology. For the SNP × housing system interaction, the annotated genes ASXL1 and NOL4L on BTA 13 were relevant for DD-sick and DD-acute. Overall, the very similar genetic parameters for the same traits in different environments and negligible genotype × housing system interactions indicate only minor effects on genetic evaluations for DD due to housing-system particularities.

Invasive candidiasis poses a life-threatening risk, and early prognosis assessment is vital for timely interventions to reduce mortality. Serum C5a levels have recently been linked to prognosis, but confirmation in cancer patients is pending.

We detected the concentrations of serum C5a in hospitalized cancer patients with invasive candidiasis from 2020 to 2023, and retrospectively analyzed the clinical data.

372 cases were included in this study, with a 90-day mortality rate of 21.8%. Candida albicans (48.7%) remained the predominant pathogen, followed by Candida glabrata (25.5%), Candida tropicalis (12.4%), and Candida parapsilosis (8.3%). Gastrointestinal cancer was the most diagnosed pathology type (37.6%). Serum C5a demonstrated a noteworthy correlation with 90-day mortality, and employing a cutoff value of 36.7 ng/ml revealed significantly higher 90-day mortality in low-C5a patients (41.2%) compared to high-C5a patients (6.3%) (p < 0.001). We also identified no source control, no surgery, metastasis, or chronic renal failure independently correlated with the 90-day mortality. Based on this, a prognostic model combining C5a and clinical parameters was constructed, which performed better than models built solely on C5a or clinical parameters. Furthermore, we weighted scores to each parameter in the model and presented diagnostic sensitivity and specificity corresponding to different score points calculated by the model.

We constructed a prognostic scoring model including serum C5a and clinical parameters, which would contribute to precise prognosis assessment and benefit the outcome among cancer patients.

Historically, the complement system (classical, lectin, alternative, and terminal pathways) is known to play a crucial role in the etiopathogenesis of many kidney diseases. Direct or indirect activation in these settings is revealed by consumption of complement proteins at the serum level and kidney tissue deposition seen by immunofluorescence and electron microscopy. The advent of eculizumab has shown that complement inhibitors may improve the natural history of certain kidney diseases. Since then, the number of available therapeutic molecules and experimental studies on complement inhibition has increased exponentially. In our narrative review, we give a summary of the main complement inhibitors that have completed phase II and phase III studies or are currently used in adult and pediatric nephrology. The relevant full-text works, abstracts, and ongoing trials (clinicaltrials.gov site) are discussed. Data and key clinical features are reported for eculizumab, ravulizumab, crovalimab, avacopan, danicopan, iptacopan, pegcetacoplan, and narsoplimab. Many of these molecules have been shown to be effective in reducing proteinuria and stabilizing kidney function in different complement-mediated kidney diseases. Thanks to their efficacy and target specificity, these novel drugs may radically improve the outcome of complement-mediated kidney diseases, contributing to an improvement in our understanding of their underlying pathophysiology.

Acute lung injury (ALI) is an acute respiratory-related progressive disorder, which lacks specific pharmacotherapy. Icariin (ICA) has been shown to be effective in treating ALI. However, the targets and pharmacological mechanisms underlying the effects of ICA in the treatment of ALI are relatively lacking. Based on network pharmacology and molecular docking analyses, the gene functions and potential target pathways of ICA in the treatment of ALI were determined. In addition, the underlying mechanisms of ICA were verified by immunohistochemistry, immunofluorescence, quantitative Real-time PCR, and Western blot in LPS-induced ALI mice. The biological processes targeted by ICA in the treatment of ALI included the pathological changes, inflammatory response, and cell signal transduction. Network pharmacology, molecular docking, and in vivo experimental results revealed that ICA inhibited the complement C5a-C5aR1 axis, TLR4 mediated NF-κB, MAPK, and JAK2-STAT3 signaling pathways related gene and protein expressions, and decreased inflammatory cytokine, chemokine, adhesion molecule expressions, and mitochondrial apoptosis in LPS-induced ALI.