Csf2 Attenuated Sepsis-Induced Acute Kidney Injury by Promoting Alternative Macrophage Transition

Macrophage polarization in sepsis: Emerging role and clinical application prospect

Sepsis is a severe, potentially fatal condition defined by organ dysfunction due to excessive inflammation. Its complex pathogenesis and poor therapeutic outcomes pose significant challenges in treatment. Macrophages, with their high heterogeneity and plasticity, play crucial roles in both the innate and adaptive immune systems. They can polarize into M1-like macrophages, which promote pro-inflammatory responses, or M2-like macrophages, which mediate anti-inflammatory responses, positioning them as critical mediators in the immune response during sepsis.Macrophages are the main regulators of inflammatory responses, and their polarization is also regulated by inflammatory signaling pathways. This review highlights recent advances in the inflammatory signaling pathways involved in sepsis, mechanism of macrophage polarization mediated by inflammation-related signaling pathways in sepsis, and the role of signaling pathway mediated macrophage polarization in organ dysfunction involved in sepsis. We also explore the therapeutic potential of targeting macrophage polarization for immunotherapy, offering new perspectives on macrophage-targeted treatments for sepsis.

Critical Role of S100A9 in Sepsis-associated Acute Kidney Injury: Mechanistic Insights through Pyroptosis Pathway Modulation

This study investigates the role of S100A9 in sepsis-associated AKI (SA-AKI) through the lens of pyroptosis, a controlled form of cell death mediated by the gasdermin protein family. Using C57BL/6 mice and S100A9 knockout mice subjected to cecal ligation and puncture (CLP), RNA sequencing and bioinformatics analyses revealed differentially expressed genes (DEGs) related to inflammation and immune responses, with notable upregulation of S100A9. Functional enrichment analyses (GO and KEGG) indicated these DEGs are involved in interferon-beta response, immune processes, and cell adhesion. Protein-protein interaction (PPI) network analyses further emphasized S100A9's pivotal role in SA-AKI.Clinical validation measured S100A9 levels in serum and urine samples from SA-AKI patients and healthy volunteers, finding elevated S100A9 levels in the former. In vivo experiments showed that S100A9 knockout mice exhibited reduced kidney injury and inflammation, indicated by lower serum creatinine, urea nitrogen, and inflammatory markers (IL-1β and IL-18). Histopathological analyses and immunohistochemistry confirmed less renal damage and reduced expression of cleaved IL-1β and GSDMD-N in S100A9-deficient mice. Electron microscopy and Western blotting validated that S100A9 deficiency mitigates caspase-1-dependent pyroptosis.Cellular experiments with HK-2 cells demonstrated that S100A9 knockdown alleviated LPS-induced cell damage and reduced pyroptosis markers. These findings illuminate S100A9's involvement in NLRP3 inflammasome activation and pyroptosis, suggesting potential therapeutic targets for SA-AKI. Targeting S100A9 may offer new therapeutic avenues, improving outcomes for sepsis-related kidney injury patients. Future research should aim to validate these findings in larger clinical settings.

Elevated hydrostatic pressure disturbs expression of growth factors in human renal epithelial cells

Obstructive uropathy is a common kidney disease caused by elevated hydrostatic pressure (HP), but relevant molecular and cellular mechanisms have not yet been well understood. In this study, we ex vivo investigated the effects of elevated HP on human renal epithelial cells (HREpCs). Primary HREpCs were subjected to 100 cmH2O HP for 8 or 48 h. Then, the cells were cultured without HP stimulation for another 24 h or 72 h. Cell morphology showed almost no change after 8h HP treatment, but exhibited reversible elongation after 48h HP treatment. HP treatment for 8 h increased the expression of TGFB1 and VEGFA but decreased the expression of CSF2 and TGFB2. On the other hand, HP treatment for 48 h downregulated the expression of CSF2, TGFB2, PDGFB, VEGFA, and VEGFB, while upregulated the expression of TGFB3. Interestingly, all changes induced by 48 h HP treatment were detected more severe compared to 8 h HP treatment. In conclusion, elongated ex vivo HP loading to renal epithelial cells induces reversible changes on cell morphology and disturbs the expression of several growth factors, which provides novel mechanistic insight on elevated HP-caused kidney injury such as obstructive uropathy.

GSDMD and GSDME synergy in the transition of acute kidney injury to chronic kidney disease

BACKGROUND AND HYPOTHESIS

Acute kidney injury (AKI) could progress to chronic kidney disease (CKD) and the AKI-CKD transition has major clinical significance. A growing body of evidence has unveiled the role of pyroptosis in kidney injury. We postulate that GSDMD and GSDME exert cumulative effects on the AKI-CKD transition by modulating different cellular responses.

METHODS

We established an AKI-CKD transition model induced by folic acid in wildtype (WT), Gsdmd-/-, Gsdme-/-, and Gsdmd-/-Gsdme-/- mice. Tubular injury, renal fibrosis and inflammatory responses were evaluated. In vitro studies were conducted to investigate the interplay among tubular cells, neutrophils, and macrophages.

RESULTS

Double deletion of Gsdmd and Gsdme conferred heightened protection against AKI, mitigating inflammatory responses, including the formation of neutrophil extracellular traps (NETs), macrophage polarization and differentiation, and ultimately renal fibrosis, compared with wildtype mice and mice with single deletion of either Gsdmd or Gsdme. Gsdme, but not Gsdmd deficiency, shielded tubular cells from pyroptosis. GSDME-dependent tubular cell death stimulated NETs formation and prompted macrophage polarization towards a pro-inflammatory phenotype. Gsdmd deficiency suppressed NETs formation and subsequently hindered NETs-induced macrophage-to-myofibroblast transition (MMT).

CONCLUSION

GSDMD and GSDME collaborate to contribute to AKI and subsequent renal fibrosis induced by folic acid. Synchronous inhibition of GSDMD and GSDME could be an innovative therapeutic strategy for mitigating the AKI-CKD transition.

Inherited KDM6AA649T facilitates tumor-immune escape and exacerbates colorectal signet-ring cell carcinoma outcomes

Childhood onset of colorectal signet-ring cell carcinoma (CR-SRCC) is extremely rare and featured as highly malignant with poor prognosis. Here we reported a CR-SRCC case of 11-year-old boy with a novel inherited X-linked KDM6AA694T mutation. The H3K27me3 demethylase KDM6A was frequently mutated in varieties of tumors and acts as a tumor suppressor. In vivo H3K27me3 demethylation assay demonstrated that KDM6AA694T had dampened H3K27me3 demethylase activity. Overexpression of KDM6AA694T in SRCC cell line KATO3 promoted cell proliferation, invasion and migration, which were further confirmed in vivo by constructing orthotopic tumor growth and lung metastasis model. Besides, expression of KDM6AA694T in immune cells suppresses inflammatory macrophage response and effector T cell response. In conclusion, we characterized a novel inherited KDM6AA694T mutant from a childhood-onset SRCC case and demonstrated that the mutant with impaired H3K27me3 demethylase activity could potentiate tumor malignancy and suppress antitumor immunity.

Dehydroandrographolide facilitates M2 macrophage polarization by downregulating DUSP3 to inhibit sepsis-associated acute kidney injury

BACKGROUND

Sepsis is perceived as lethal tissue damage and significantly increases mortality in combination with acute kidney injury (AKI). M2 macrophages play important roles in the secretion of anti-inflammatory and tissue repair mediators. We aimed to study the role of Dehydroandrographolide (Deh) in sepsis-associated AKI in vitro and in vivo through lipopolysaccharide (LPS)-induced macrophages model and cecal ligation and puncture-induced AKI mice model, and to reveal the mechanism related to M2 macrophage polarization.

METHODS

Enzyme-linked immunosorbent assay kits were used to assess the levels of inflammatory factors. Expression of markers related to M1 macrophages and M2 macrophages were analyzed. Additionally, dual specificity phosphatase 3 (DUSP3) expression was tested. Cell apoptosis was evaluated by flow cytometry analysis and terminal-deoxynucleotidyl transferase-mediated nick end labeling staining. Moreover, renal histological assessment was performed by using hematoxylin and eosin staining.

RESULTS

Deh reduced inflammation of THP-1-derived macrophages exposed to LPS. Besides, Deh induced the polarization of M1 macrophages to M2 and downregulated DUSP3 expression in THP-1-derived macrophages under LPS conditions. Further, DUSP3 overexpression reversed the impacts of Deh on the inflammation and M2 macrophages polarization of THP-1-derived macrophages stimulated by LPS. Additionally, human proximal tubular epithelial cells (HK-2) in the condition medium from DUSP3-overexpressed THP-1-derived macrophages treated with LPS and Deh displayed decreased viability and increased apoptosis and inflammation. The in vivo results suggested that Deh improved the renal function, ameliorated pathological injury, induced the polarization of M1 macrophages to M2, suppressed inflammation and apoptosis, and downregulated DUSP3 expression in sepsis-induced mice.

CONCLUSION

Deh facilitated M2 macrophage polarization by downregulating DUSP3 to inhibit septic AKI.

Combined metabolomic and proteomic analysis of sepsis related acute liver injury and its pathogenesis research

BACKGROUND

Sepsis-induced acute liver injury is common in patients in intensive care units. However, the exact mechanism of this condition remains unclear. The purpose of this study was to investigate the roles and mechanisms of proteins and metabolites in the liver tissue of mice after sepsis and elucidate the molecular biological mechanisms of sepsis-related liver injury.

METHODS

First, a lipopolysaccharide (LPS)-induced sepsis mouse model was established. Then, according to alanine aminotransferase (ALT) and aspartate aminotransferase (AST) detection in mouse serum and liver histopathological examination (HE) staining, the septic mice were divided into two groups: acute liver injury after sepsis and nonacute liver injury after sepsis. Metabolomics and proteomic analyses were performed on the liver tissues of the two groups of mice to identify significantly different metabolites and proteins. The metabolomics and proteomics results were further analysed to identify the biological indicators and pathogenesis related to the occurrence and development of sepsis-related acute liver injury at the protein and metabolite levels.

RESULTS

A total of 14 differentially expressed proteins and 46 differentially expressed metabolites were identified. Recombinant Erythrocyte Membrane Protein Band 4.2 (Epb42) and adenosine diphosphate (ADP) may be the key proteins and metabolites responsible for sepsis-related acute liver injury, according to the correlation analysis of proteomics and metabolomics. The expression of the differential protein Epb42 was further verified by western blot (WB) detection.

CONCLUSIONS

Our study suggests that the differential protein Epb42 may be key proteins causing sepsis-associated acute liver injury, providing new and valuable information on the possible mechanism of sepsis-associated acute liver injury.

Differential gene expression of Wharton's jelly-derived mesenchymal cells mediated by graphene oxide in basal and osteo-induced media

BACKGROUND

Graphene oxide (GO) is widespread in scaffold engineering owing to its extraordinary properties such as multiple oxygen functional groups, high hydrophilicity ability and biocompatibility. It is known to promote differentiation in mesenchymal stem cells, but concomitant comparison of its modulation on the expression profiles of Wharton's jelly (WJ)-MSC surface markers, lineage differentiation, and epigenetic regulatory genes in basal and induced condition are still lacking. Unraveling the fundamental mechanisms is essential for the effective utilization of WJ-MSCs incorporated with GO in therapy. This study aims to explore the unique gene expression profiles and epigenetic characteristics of WJ-MSCs influenced by GO.

METHODS AND RESULTS

The characterized GO-coated coverslip served as a substrate for culturing WJ-MSCs. In addition to investigating the impact of GO on cell proliferation and differentiation, we conducted a gene expression study using PCR array, while epigenetic control was assessed through bisulfite sequencing and Western blot analysis. Our findings indicate that the presence of GO maintained the proliferation and survival of WJ-MSCs. In the absence of induction, GO led to minor lipid and glycosaminoglycan deposition in WJ-MSCs. This was evidenced by the sustained expression of pluripotency and lineage-specific genes, demethylation at the OCT4 promoter, and a decrease in H3K9 methylation. In osteo-induced condition, the occurrence of osteogenesis appeared to be guided by BMP/TGF and ERK pathway activation, accompanied by the upregulation of osteogenic-related genes and downregulation of DNMT3b.

CONCLUSIONS

GO in osteo-induced condition create a favorable microenvironment that promotes the osteogenesis of WJ-MSCs by influencing genetic and epigenetic controls. This helps in advancing our knowledge on the use of GO as priming platform and WJ-MSCs an alternate source for bone repair and regeneration.

Multi-omics comprehensive analyses of programmed cell death patterns to regulate the immune characteristics of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous cancer with high morbidity and mortality. Triggering the programmed cell death (PCD) to enhance the anti-tumor therapies is being applied in multiple cancers. However, the limited understanding of genetic heterogeneity in HNSCC severely hampers the clinical efficacy. We systematically analyzed 14 types of PCD in HNSCC from The Cancer Genome Atlas (TCGA). We utilized ssGSEA to calculate the PCD scores and classify patients into two clusters. Subsequently, we displayed the genomic alteration landscape to unravel the significant differences in copy number alterations and gene mutations. Furthermore, we calculated the IC50 values of targeted drugs to predict the differences in sensitivity. To identify the immune-related prognostic types, we comprehensively estimated the relationship between immune indicators and all prognostic PCD in three datasets (TCGA, GSE65858, GSE41613). Finally, 7 regulators were filtered. Subsequently, we integrated 10 machine learning algorithms and 101 algorithm combinations to test the clinical predictive efficacy. Using WGCNA as a basis, we built a weighted co-expression network to identify modules involved in the immune landscape with different colors. Meanwhile, our results indicated that blue and red modules containing crucial regulators closely related to the CD4+, CD8+ T cells, TMB or PD-L1. FCGR2A from blue module, CSF2, INHBA, and THBS1 from the red module were determined. After verifying in vivo experiments, FCGR2A was identified as hub gene. In conclusion, our findings suggest a potential role of PCD in HNSCC, offering new insights into effective immunotherapy and anti-tumor therapies in HNSCC.

Insights into Repeated Renal Injury Using RNA-Seq with Two New RPTEC Cell Lines

Renal proximal tubule epithelial cells (RPTECs) are a primary site for kidney injury. We created two RPTEC lines from CD-1 mice immortalized with hTERT (human telomerase reverse transcriptase) or SV40 LgT antigen (Simian Virus 40 Large T antigen). Our hypothesis was that low-level, repeated exposure to subcytotoxic levels of 0.25-2.5 μM cisplatin (CisPt) or 12.5-100 μM aflatoxin B1 (AFB1) would activate distinctive genes and pathways in these two differently immortalized cell lines. RNA-seq showed only LgT cells responded to AFB1 with 1139 differentially expressed genes (DEGs) at 72 h. The data suggested that AFB1 had direct nephrotoxic properties on the LgT cells. However, both the cell lines responded to 2.5 μM CisPt from 3 to 96 h expressing 2000-5000 total DEGs. For CisPt, the findings indicated a coordinated transcriptional program of injury signals and repair from the expression of immune receptors with cytokine and chemokine secretion for leukocyte recruitment; robust expression of synaptic and substrate adhesion molecules (SAMs) facilitating the expression of neural and hormonal receptors, ion channels/transporters, and trophic factors; and the expression of nephrogenesis transcription factors. Pathway analysis supported the concept of a renal repair transcriptome. In summary, these cell lines provide in vitro models for the improved understanding of repeated renal injury and repair mechanisms. High-throughput screening against toxicant libraries should provide a wider perspective of their capabilities in nephrotoxicity.

Immunoregulatory mechanism of acute kidney injury in sepsis: A Narrative Review

Sepsis acute kidney injury (SAKI) is a common complication of sepsis, accounting for 26-50 % of all acute kidney injury (AKI). AKI is an independent risk factor for increased mortality risk in patients with sepsis. The excessive inflammatory cascade reaction in SAKI is one of the main causes of kidney damage. Both the innate immune system and the adaptive immune system are involved in the inflammation process of SAKI. Under the action of endotoxin, neutrophils, monocytes, macrophages, T cells and other complex immune network reactions occur, and a large number of endogenous inflammatory mediators are released, resulting in the amplification and loss of control of the inflammatory response. The study of immune cells in SAKI will help improve the understanding of the immune mechanisms of SAKI, and will lay a foundation for the development of new diagnostic and therapeutic targets. This article reviews the role of known immune mechanisms in the occurrence and development of SAKI, with a view to finding new targets for SAKI treatment.

Embelin attenuates lipopolysaccharide-induced acute kidney injury through the inhibition of M1 macrophage activation and NF-κB signaling in mice

Septic acute kidney injury (AKI) is commonly associated with renal dysfunction and high mortality in patients. Owing to the rapid and violent occurrence of septic AKI with inflammation, there are no effective therapies to clinically treat it. Embelin, a natural product, has a potential regulatory role in immunocytes. However, the role and mechanism of embelin in septic AKI remains unknown. This study aimed to elucidate the role of embelin in macrophage regulation in lipopolysaccharide (LPS)-induced septic AKI. Embelin was intraperitoneally administered to mice after LPS injection. And bone marrow-derived macrophages (BMDMs) were subsequently isolated from the mice to explore the immunomodulatory role of embelin in macrophages. We found that embelin attenuated renal dysfunction and pathological renal damage in the LPS-induced sepsis mouse model. Molecular docking predicted that embelin could bind to phosphorylated NF-κB p65 at the ser536 site. Embelin inhibited the translocation of NF-κB p65 via phosphorylation at ser536 in LPS-induced AKI. It also reduced the secretion of IL-1β and IL-6 and increased the secretion of IL-10 and Arg-1 of BMDMs and mice after LPS stimulation, indicating that embelin suppressed macrophage M1 activation in LPS-induced AKI. Therefore, embelin attenuated LPS-induced septic AKI by suppressing NF-κB p65 at ser536 in activated macrophages. This study preclinically suggests a therapeutic role of embelin in septic AKI.

Young Plasma Attenuated Chronic Kidney Disease Progression after Acute Kidney Injury by Inhibiting Inflammation in Mice

In the aged patients suffering from acute kidney injury, the risk for progression to chronic kidney disease and mortality is high. Aging accompanied by glomerulosclerosis, interstitial inflammation, and fibrosis might be one of the underlying mechanisms for vulnerability. In addition to sustained activation of the renin-angiotensin system, persistent chronic inflammation with tertiary lymphoid tissue formation is more common and is associated with disease progression in the aged kidney after acute injury. Based on recent laboratory evidence that young blood can rejuvenate the brain, muscle, and heart, we were intrigued by the possible protective effect of young plasma on acute kidney injury in aged mice. Here, we demonstrated that young plasma from 2-month-old mice could attenuate chronic kidney disease progression in 15-month-old mice subjected to acute kidney injury induced by ischemia-reperfusion. In the aged mice after acute kidney injury, young plasma administration decreased tubulointerstitial injury, fibrosis, and tertiary lymphoid tissue formation in kidneys assessed on day 28 after acute injury despite no significant beneficial effect on injury severity and survival. Mechanistically, young plasma inhibited angiotensin II-activated chemokines in pericytes that were responsible for tertiary lymphoid tissue formation. In summary, our data provide evidence that young plasma attenuates the transition from acute kidney injury to chronic kidney disease in aged mice. The therapeutic potential of young plasma infusion or exchange in the aged patients suffering acute kidney injury needs to be addressed in clinical trials.

Lactoferrin attenuated urban particulate matter-induced nephrotoxicity by regulating the CSF2/CENPE axis

Several epidemiological studies regarding the adverse effect of air pollution have notably accelerated in recent years. Urban particulate matter (PM) gains access to the respiratory system and translocates into the circulation to affect several tissues, such as the liver and kidneys. Lactoferrin is a substance belonging to the non-heme iron-binding glycoprotein which is present in breast milk and other exocrine fluids. Lactoferrin is protective against many pathophysiological conditions. In the present study, we explored the potential influence of lactoferrin on PM-induced nephrotoxicity. We found that lactoferrin rescued PM-induced cell death but did not affect apoptosis in human kidney cells. Lactoferrin decreased necroptosis and fibrosis but increased autophagy in human kidney cells. Furthermore, the gene expression profiles of PM and lactoferrin were analyzed by RNA sequencing. The transcriptional profiles were uploaded and analyzed by ingenuity pathway analysis software and gene set enrichment analysis. The results showed that the crucial role of the CSF2/CENPE pathway was involved in human kidney cells treated with PM and lactoferrin. In a mouse model, lactoferrin ameliorates PM-induced nephrotoxicity by regulating necroptosis, fibrosis, autophagy and the CSF2/CENPE axis. In summary, these findings showed that lactoferrin could be a novel therapeutic or preventive agent for renal disorders caused by airborne PM pollution.

CSF2RB overexpression promotes the protective effects of mesenchymal stromal cells against ischemic heart injury

Aims: The invasive intramyocardial injection of mesenchymal stromal cells (MSCs) allows for limited repeat injections and shows poor therapeutic efficacy against ischemic heart failure. Intravenous injection is an alternative method because this route allows for repeated, noninvasive, and easy delivery. However, the lack of targeting of MSCs hinders the ability of these cells to accumulate in the ischemic area after intravenous injections. We investigated whether and how the overexpression of colony-stimulating factor 2 receptor beta subunit (CSF2RB) may regulate the cardiac homing of MSCs and their cardioprotective effects against ischemic heart failure. Methods and Results: Adult mice were subjected to myocardial ischemia/reperfusion (MI/R) or sham operations. We observed significantly higher CSF2 protein expression and secretion by the ischemic heart from 1 day to 2 weeks after MI/R. Mouse adipose tissue-derived MSCs (ADSCs) were infected with adenovirus harboring CSF2RB or control adenovirus. Enhanced green fluorescent protein (EGFP)-labeled ADSCs were intravenously injected into MI/R mice every three days for a total of 7 times. Compared with ADSCs infected with control adenovirus, intravenously delivered ADSCs overexpressing CSF2RB exhibited markedly increased cardiac homing. Histological analysis revealed that CSF2RB overexpression significantly enhanced the ADSC-mediated proangiogenic, antiapoptotic, and antifibrotic effects. More importantly, ADSCs overexpressing CSF2RB significantly increased the left ventricular ejection fraction and cardiac contractility/relaxation in MI/R mice. In vitro experiments demonstrated that CSF2RB overexpression increases the migratory capacity and reduces the hypoxia/reoxygenation-induced apoptosis of ADSCs. We identified STAT5 phosphorylation as the key mechanism underlying the effects of CSF2RB on promoting ADSC migration and inhibiting ADSC apoptosis. RNA sequencing followed by cause-effect analysis revealed that CSF2RB overexpression increases the expression of the ubiquitin ligase RNF4. Coimmunoprecipitation and coimmunostaining experiments showed that RNF4 binds to phosphorylated STAT5. RNF4 knockdown reduced STAT5 phosphorylation as well as the antiapoptotic and promigratory actions of ADSCs overexpressing CSF2RB. Conclusions: We demonstrate for the first time that CSF2RB overexpression optimizes the efficacy of intravenously delivered MSCs in the treatment of ischemic heart injury by increasing the response of the MSCs to a CSF2 gradient and CSF2RB-dependent STAT5/RNF4 activation.

Histone H3K27 methyltransferase EZH2 regulates apoptotic and inflammatory responses in sepsis-induced AKI

Rationale: The role of histone methylation modifications in renal disease, particularly in sepsis-induced acute kidney injury (AKI), remains unclear. This study aims to investigate the potential involvement of the histone methyltransferase zeste homolog 2 (EZH2) in sepsis-induced AKI and its impact on apoptosis and inflammation. Methods: We first examined the expression of EZH2 in the kidney of sepsis-induced AKI (LPS injection) mice and LPS-stimulated tubular epithelial cells. We next constructed the EZH2 knockout mice to further confirm the effects of EZH2 on apoptosis and inflammatory response in AKI. And the inflammatory level of epithelial cells can be reflected by detecting chemokines and the chemotaxis of macrophages. Subsequently, we constructed the EZH2 knocked-down cells again and performed Chromatin Immunoprecipitation sequencing to screen out the target genes regulated by EZH2 and the enrichment pathway. Then we confirmed the EZH2 target gene and its regulatory pathway in vivo and in vitro experiments. Experimental results were finally confirmed using another in vivo model of sepsis-induced AKI (cecal perforation ligation). Results: The study found that EZH2 was upregulated in sepsis-induced AKI and that silencing EZH2 could reduce renal tubular injury by decreasing apoptosis and inflammatory response of tubular epithelial cells. EZH2 knockout mice showed significantly reduced renal inflammation and macrophage infiltration. Chromatin immunoprecipitation sequencing and polymerase chain reaction identified Sox9 as a target of EZH2. EZH2 was found to be enriched on the promoter of Sox9. Silencing EZH2 resulted in a significant increase in the transcriptional level of Sox9 and activation of the Wnt/β-catenin signaling pathway. The study further reversed the effects of EZH2 silencing by silencing Sox9 or administering the Wnt/β-catenin inhibitor icg001. It was also found that Sox9 positively regulated the expression of β-catenin and its downstream pathway-related genes. Finally, the study showed that the EZH2 inhibitor 3-deazaneplanocin A significantly alleviated sepsis-induced AKI. Conclusion: Our results indicate that silencing EZH2 can protect renal function by relieving transcriptional inhibition of Sox9, activating the Wnt/β-catenin pathway, and attenuating tubular epithelial apoptosis and inflammatory response of the renal interstitium. These results highlight the potential therapeutic value of targeting EZH2 in sepsis-induced AKI.

Bibliometric and visualization analysis of kidney repair associated with acute kidney injury from 2002 to 2022

Background: Renal repair is closely related to the prognosis of acute kidney injury (AKI) and has attracted increasing attention in the research field. However, there is a lack of a comprehensive bibliometric analysis in this research area. This study aims at exploring the current status and hotspots of renal repair research in AKI from the perspective of bibliometrics. Methods: Studies published between 2002 and 2022 related to kidney repair after AKI were collected from Web of Science core collection (WoSCC) database. Bibliometric measurement and knowledge graph analysis to predict the latest research trends in the field were performed using bibliometrics software CiteSpace and VOSviewer. Results: The number of documents related to kidney repair after AKI has steadily increased over 20 years. The United States and China contribute more than 60% of documents and are the main drivers of research in this field. Harvard University is the most active academic institution that contributes the most documents. Humphreys BD and Bonventre JV are the most prolific authors and co-cited authors in the field. The American Journal of Physiology-Renal Physiology and Journal of the American Society of Nephrology are the most popular journals in the field with the greatest number of documents. "exosome", "macrophage polarization", "fibroblast", and" aki-ckd transition" are high-frequency keywords in this field in recent years. Extracellular vesicles (including exosomes), macrophage polarization, cell cycle arrest, hippo pathway, and sox9 are current research hotspots and potential targets in this field. Conclusion: This is the first comprehensive bibliometric study on the knowledge structure and development trend of AKI-related renal repair research in recent years. The results of the study comprehensively summarize and identify research frontiers in AKI-related renal repair.

Theacrine alleviates sepsis-induced acute kidney injury by repressing the activation of NLRP3/Caspase-1 inflammasome

Acute kidney injury (AKI) is a frequent and serious complication of sepsis, which results in a rapid decline of kidney function. Currently, there are no curative therapies for AKI. Theacrine is a purine alkaloid and exerts significant role in regulating inflammation, oxidative stress, and mood elevation. The study aims to evaluate the biological role and potential mechanism of theacrine in septic AKI. The murine and cellular models of septic AKI were established in lipopolysaccharide (LPS)-treated C57BL/6 mice and HK-2 cells, respectively. The effect of theacrine on alleviating septic AKI was assessed after pretreatment with theacrine in vivo and in vitro. We found that theacrine treatment significantly alleviated LPS-induced kidney injury, as evidenced by decreased levels of kidney injury markers (blood urea nitrogen and creatinine), inflammatory factors (IL-1β and IL-18), and cell apoptosis in vivo and in vitro. Mechanistically, theacrine markedly repressed the activation of NOD-like receptor (NLR) pyrin domain-containing protein 3 (NLRP3)inflammasome. As expected, MCC950 (a specific inhibitor of NLRP3) treatment also decreased LPS-induced production of IL-18 and IL-1β and cell apoptosis in HK-2 cells. More important, Nigericin sodiumsalt (a NLRP3 agonist) damaged the effect of theacrine on repressing kidney injury markers (blood urea nitrogen and creatinine), pro-inflammatory cytokines (IL-18 and IL-1β), and cell apoptosis. Taken together, these results demonstrate that theacrine alleviates septic AKI, at least in part by repressing the activation of NLRP3 inflammasome.

Clec7a expression in inflammatory macrophages orchestrates progression of acute kidney injury

Acute kidney injury (AKI) is associated with high risk of mortality, post-disease renal fibrosis, kidney dysfunction and renal failure. Renal macrophages play a key role in the pathogenesis (M1 subpopulation), healing and remodeling (M2 subpopulation) in AKI and, thus, have been a promising target for clinical treatment of AKI. Here, in a mouse renal ischemia/reperfusion injury (IRI) model for AKI, we showed that renal macrophages could be further classified into Clec7a+ M1 macrophages, Clec7a- M1 macrophages, Clec7a+ M2 macrophages and Clec7a- M2 macrophages, representing distinct macrophage populations with different functionality. Interestingly, Clec7a+ M1 macrophages exhibited potent pro-inflammatory and phagocytic effects compared to Clec7a- M1 macrophages, while Clec7a- M2 macrophages exhibited better proliferating and migrating potential, which is critical for their role in tissue repairing after injury. These data from mice were further strengthened by bioinformatics analyses using published database. In vivo, combined expression of Clec7a in M1 macrophages and depletion of Clec7a in M2 macrophages significantly improved the renal function after IRI-AKI. Together, our data suggest that Clec7a is crucial for the fine regulation of macrophage phenotype during AKI and could be a novel target for boosting clinical therapy.

Knockdown of P2Y4 ameliorates sepsis-induced acute kidney injury in mice via inhibiting the activation of the NF-κB/MMP8 axis

Sepsis-induced acute kidney injury (S-AKI) has emerged as a frequent and life-threatening complication in critically ill patients, which is characterized by a systematic inflammatory response and a rapid decline in kidney function. P2Y4, a member of G protein–coupled P2Y nucleotide receptor family, has been reported to serve as a crucial player in inflammatory responses during the development of neurocognitive disorder and myocardial infarction. Nonetheless, the biological role of P2Y4 in S-AKI remains largely unclear. This study aimed to decipher the biological role of P2Y4 in S-AKI and illuminate the potential mechanisms. In this study, S-AKI models were successfully established in mice via cecal ligation and puncture. Results showed that the kidney tissues from S-AKI mouse models exhibited a higher P2Y4 expression level than from the sham-operated group. Knockdown of P2Y4 was found to remarkably alleviate kidney damage and reduce inflammatory response in mice of S-AKI models. Moreover, P2Y4 ablation inhibited the activation of the NF-κB/MMP-8 signaling axis. Additionally, mechanistic studies revealed that rescuing MMP-8 reversed the alleviating effects of P2Y4 knockdown against renal cell damage. Collectively, our findings indicate that P2Y4 knockdown ameliorated S-AKI in mice via inhibiting the activation of the NF-κB/MMP-8 axis and that P2Y4 may represent a novel therapeutic target for S-AKI patients.

Roles of CSF2 as a modulator of inflammation during retinal degeneration

Colony-stimulating factor 2 (CSF2) is a potent cytokine that stimulates myeloid cells, such as dendritic cells and macrophages. We have been analyzing the roles of microglia in retinal degeneration through the modulation of inflammation in the eye, and examined the roles of CSF2 in this process. Both subunits of the CSF2 receptor are expressed in microglia, but no evidence suggesting the involvement of CSF2 in inflammation in the degenerating eye has been reported. We found that Csf2 transcripts were induced in the early phase of in vitro mouse adult retina culture, used as degeneration models, suggesting that CSF2 induction is one of the earliest events occurring in the pathology of retinal degeneration. The administration of CSF2 into the retina after systemic NaIO₃ treatment increased the number of microglia. To examine the roles of CSF2 in retinal inflammation, we overexpressed CSF2 in retinal explants. Induction of CSF2 activated microglia and Müller glia, and the layer structure of the retina was severely perturbed. CC motif chemokine ligand 2 (Ccl2) and C-X-C motif chemokine ligand 10 (Cxcl10), both of which are expressed in activated microglia, were strongly induced by the expression of CSF2 in the retina. The addition of CSF2 to primary retinal microglia and the microglial cell lines MG5 and BV2 showed statistically significant increase in Ccl2 and Il1b transcripts. Furthermore, CSF2 induced proliferation, migration, and phagocytosis in MG5 and/or BV2. The effects of CSF2 on microglia were mild, suggesting that CSF2 induced strong inflammation in the context of the retinal environment.

Macrophages in Renal Injury, Repair, Fibrosis Following Acute Kidney Injury and Targeted Therapy

Acute kidney injury (AKI) is a renal disease with a high incidence and mortality. Currently, there are no targeted therapeutics for preventing and treating AKI. Macrophages, important players in mammalian immune response, are involved in the multiple pathological processes of AKI. They are dynamically activated and exhibit a diverse spectrum of functional phenotypes in the kidney after AKI. Targeting the mechanisms of macrophage activation significantly improves the outcomes of AKI in preclinical studies. In this review, we summarize the role of macrophages and the underlying mechanisms of macrophage activation during kidney injury, repair, regeneration, and fibrosis and provide strategies for macrophage-targeted therapies.

Interaction Between Intrinsic Renal Cells and Immune Cells in the Progression of Acute Kidney Injury

A growing number of studies have confirmed that immune cells play various key roles in the pathophysiology of acute kidney injury (AKI) development. After the resident immune cells and intrinsic renal cells are damaged by ischemia and hypoxia, drugs and toxins, more immune cells will be recruited to infiltrate through the release of chemokines, while the intrinsic cells promote macrophage polarity conversion, and the immune cells will promote various programmed deaths, phenotypic conversion and cycle arrest of the intrinsic cells, ultimately leading to renal impairment and fibrosis. In the complex and dynamic immune microenvironment of AKI, the bidirectional interaction between immune cells and intrinsic renal cells affects the prognosis of the kidney and the progression of fibrosis, and determines the ultimate fate of the kidney.

Correlation between perioperative parecoxib use and postoperative acute kidney injury in patients undergoing radical mastectomy: a retrospective cohort analysis

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely prescribed drugs worldwide. However, the effect of NSAIDS on postoperative renal function is still unclear. Few studies have assessed the effects of parecoxib on renal function. Our aim is to investigate a correlation between parecoxib and the presence or absence of AKI postoperatively after a breast cancer surgery operation.

Methods

This was a retrospective cohort study that we performed on our hospitalized database. From January 2012 to August 2021, 3542 female patients undergoing radical mastectomy were enrolled, all data including the patients' information and laboratory results were obtained from electronic medical system. The main outcome was the incidence of AKI postoperatively. AKI was defined in accordance with the KDIGO criteria. Study groups were treated with or without parecoxib. Univariable and multivariable logistic regression analyses were performed.

Results

In our study, about 5.76% experienced AKI. The incidence rate of postoperative AKI (3.49%) within 7 days in the parecoxib group was lower than that in the control group (6.00%, P = 0.05). Compared to the control group, the AKI’s incidence was reduced by 49% (OR = 0.46; 95%CI 0.27–0.97) in parecoxib group in multivariable logistic regression analysis. There was a reduction in the incidence of postoperative AKI in other three subgroups: preoperative eGFR < 90 mL/min·1.73/m2 (OR = 0.52; 95%CI 0.27–0.97), blood loss < 1000 ml (OR = 0.48; 95%CI 0.24–0.96) and non-diabetes (OR = 0.51; 95%CI 0.26–0.98).

Conclusions

Parecoxib was associated with incidence of postoperative acute kidney injury.

Driving role of macrophages in transition from acute kidney injury to chronic kidney disease

Acute kidney injury (AKI), characterized by acute renal dysfunction, is an increasingly common clinical problem and an important risk factor in the subsequent development of chronic kidney disease (CKD). Regardless of the initial insults, the progression of CKD after AKI involves multiple types of cells, including renal resident cells and immune cells such as macrophages. Recently, the involvements of macrophages in AKI-to-CKD transition have garnered significant attention. Furthermore, substantial progress has also been made in elucidating the pathophysiological functions of macrophages from the acute kidney to repair or fibrosis. In this review, we highlight current knowledge regarding the roles and mechanisms of macrophage activation and phenotypic polarization, and transdifferentiation in the development of AKI-to-CKD transition. In addition, the potential of macrophage-based therapy for preventing AKI-to-CKD transition is also discussed.

Account of Deep Learning-Based Ultrasonic Image Feature in the Diagnosis of Severe Sepsis Complicated with Acute Kidney Injury

This study was aimed at analyzing the diagnostic value of convolutional neural network models on account of deep learning for severe sepsis complicated with acute kidney injury and providing an effective theoretical reference for the clinical use of ultrasonic image diagnoses. 50 patients with severe sepsis complicated with acute kidney injury and 50 healthy volunteers were selected in this study. They all underwent ultrasound scans. Different deep learning convolutional neural network models dense convolutional network (DenseNet121), Google inception net (GoogLeNet), and Microsoft's residual network (ResNet) were used for training and diagnoses. Then, the diagnostic results were compared with professional image physicians' artificial diagnoses. The results showed that accuracy and sensitivity of the three deep learning algorithms were significantly higher than professional image physicians' artificial diagnoses. Besides, the error rates of the three algorithm models for severe sepsis complicated with acute kidney injury were significantly lower than professional physicians' artificial diagnoses. The areas under curves (AUCs) of the three algorithms were significantly higher than AUCs of doctors' diagnosis results. The loss function parameters of DenseNet121 and GoogLeNet were significantly lower than that of ResNet, with the statistically significant difference (P < 0.05). There was no significant difference in training time of ResNet, GoogLeNet, and DenseNet121 algorithms under deep learning, as the convergence was reached after 700 times, 700 times, and 650 times, respectively (P > 0.05). In conclusion, the value of the three algorithms on account of deep learning in the diagnoses of severe sepsis complicated with acute kidney injury was higher than professional physicians' artificial judgments and had great clinical value for the diagnoses and treatments of the disease.

The Active Components of Sunflower (Helianthus annuus L.) Calathide and the Effects on Urate Nephropathy Based on COX-2/PGE2 Signaling Pathway and the Urate Transporter URAT1, ABCG2, and GLUT9

The sunflower (Helianthus annuus L.) calathide is gradually used as an alternative treatment for hyperuricemia; nevertheless, evidence regarding its main components and therapeutic capacity for urate nephropathy is lacking. Identification of sunflower calathide aqueous extract (SCE) was rapidly done by UPLC-ESI-Q-Orbitrap, and 32 water-soluble compounds with a comprehensive score >80 were discovered. Besides, yeast extract was administrated to induce high UA levels and hyperuricemic renal injury. We found that SCE treatment not only decreased UA levels to a comparable degree as allopurinol and benzbromarone, but also reduced the BUN levels and participated in kidney injury repair induced by uric acid. Moreover, it regulated the expression of URAT1 and ABCG2, especially inhibiting the GLUT9 in the normal kidney. Results were multifacetedly evaluated with a view to suggesting a possible mechanism of action as compared with those of allopurinol and benzbromarone by western blotting, H&E staining, and immunohistochemistry. However, the H&E staining showed histological changes in model, benzbromarone, and allopurinol groups rather than SCE treatments, and at the same time, the uric acid was identified as a cause of renal damage. The antiinflammatory effects and the regulations of COX-2/PGE2 signaling pathway were revealed on the LPS-induced RAW264.7 cells, indicating that the SCE not only increased cellular proliferation but also downregulated the COX-2, PGE2, NO, and IFN-γ cytokines in the RAW264.7 cells. To conclude, the SCE acts on urate transporters and contributes to prevent urate nephropathy via alleviating inflammatory process involving COX-2/PGE2 signaling pathway. It is available to develop SCE as food supplemental applications for hyperuricemia and nephritic inflammation.

Rhodomeroterpene alleviates macrophage infiltration and the inflammatory response in renal tissue to improve acute kidney injury

Inflammation is broadly recognized as an important factor in the pathogenesis of acute kidney injury (AKI), but pharmacological approaches to alleviate inflammation in AKI have not been proved successful in clinical trials. Macrophage infiltration into renal tissue promotes inflammatory responses that contribute to the pathogenesis of AKI. Suppression of renal tissue inflammatory responses is postulated to improve renal injury of patients and animals. Rhodomeroterpene (RMT) is a novel meroterpenoid isolated from the Rhododendron genus that was shown to exert anti-inflammatory action in vivo or in vitro in this study. We investigated the treatment effects of RMT on LPS-induced sepsis and two different AKI models. The results showed that pretreatment with RMT (30 mg kg^-1  d^-1 , ip, for 3 days) significantly inhibited acute inflammatory responses in LPS-induced septic mice. In both renal ischemia-reperfusion injury (I/R) and sepsis-induced AKI models, RMT (30 mg kg^-1  d^-1 , ip, for 3 days) ameliorated renal function and injury and alleviated inflammation by reducing the infiltration of immune cells, including macrophages and neutrophils. Furthermore, our study demonstrated that RMT inhibits inflammatory responses in macrophages. The anti-inflammatory effects of RMT may be due to the inactivation of the IKK/NF-κB and PI3K/PDK1/Akt inflammatory signaling pathways in macrophages. Collectively, our findings indicate that RMT ameliorates renal injury and alleviates the renal inflammatory state in different AKI models, suggesting that RMT may be a potential agent for the treatment of AKI.

Spi-B Promotes the Recruitment of Tumor-Associated Macrophages via Enhancing CCL4 Expression in Lung Cancer

Tumor immune escape plays a critical role in malignant tumor progression and leads to the failure of anticancer immunotherapy. Spi-B, a lymphocyte lineage-specific Ets transcription factor, participates in mesenchymal invasion and favors metastasis in human lung cancer. However, the mechanism through which Spi-B regulates the tumor immune environment has not been elucidated. In this study, we demonstrated that Spi-B enhanced the infiltration of tumor-associated macrophages (TAMs) in the tumor microenvironment using subcutaneous mouse models and clinical samples of human lung cancer. Spi-B overexpression increased the expression of TAM polarization- and recruitment-related genes, including CCL4. Moreover, deleting CCL4 inhibited the ability of Spi-B promoting macrophage infiltration. These data suggest that Spi-B promotes the recruitment of TAMs to the tumor microenvironment via upregulating CCL4 expression, which contributes to the progression of lung cancer.

The roles of macrophage polarization in the host immune response to sepsis

Sepsis is a life-threatening clinical syndrome caused by infection. Its pathogenesis is complex and entails coagulation dysfunction, inflammation, and immune disorders. Macrophages are important components of innate and adaptive immunity that are highly heterogeneous and plastic. They can polarize into a multi-dimensional spectrum of phenotypes with different functions relating to immune regulation in response to changes in the microenvironment of specific tissues. We reviewed studies that examined the role of macrophage polarization with a focus on the classical activated (M1-like) and alternative activated (M2-like) macrophages as the two main phenotypes involved in the host immune response to sepsis. A complex regulatory network is involved in the process of macrophage polarization, which is influenced by a variety of signaling molecules, transcription factors, epigenetic modifications, and metabolic reprogramming. M1-like macrophages release large quantities of pro-inflammatory mediators, while M2-like macrophages release large quantities of anti-inflammatory mediators. An imbalance between M1-like and M2-like macrophages induces the occurrence and development of sepsis. Therefore, targeted regulation of the process of macrophage polarization could be a useful approach to normalize the immune balance of the host, offering a new treatment modality for different stages of sepsis.

Effects of circular RNA Ttc3/miR-148a/Rcan2 axis on inflammation and oxidative stress in rats with acute kidney injury induced by sepsis

Aim Increasing evidence demonstrated circular RNAs (circRNAs) are involved in the development of various diseases, including sepsis-induced AKI. Although CIRC-Ttc3 has been proved to regulate cardiac function after myocardial infarction, its role in sepsis-induced AKI remains unclear.

MATERIALS AND METHODS

The AKI rat model was firstly induced by sepsis through cecal ligation puncture (CLP). Serum levels of creatinine, BUN, NGAL, TNF-α, IL-6, SOD, MDA and IL-1β were measured through appropriate kits. The pathological alteration and renal microvascular permeability in renal tissues were determined by HE staining and Evans Blue assays. Cell apoptosis was detected by TUNEL assay. The expression levels of CIRC-Ttc3, miR-148a, TNF-α, IL-1β and iNOS in rats' renal samples were tested by qRT-PCR or/and western blot. The binding ability between CIRC-Ttc3 and miR-148a was evaluated through luciferase reporter, RIP and RNA pull-down assays.

KEY FINDINGS

Kidney injury was found in CLP-treated rats. CIRC-Ttc3 expression was down-regulated, and upregulation of CIRC-Ttc3 improved inflammatory responses and oxidative stress in AKI rats. Mechanismly, CIRC-Ttc3 was confirmed to bind to and negatively regulate miR-148a. Further rescue assays revealed that overexpression of miR-148a rescued the improvement of CIRC-Ttc3 on sepsis-induced AKI. Then, it was illustrated that CIRC-Ttc3 regulated Rcan2 expression by binding to miR-148a. Finally, knockdown of Rcan2 reversed the effects of miR-148a inhibition on sepsis-induced AKI.

SIGNIFICANCE

CIRC-Ttc3 relieved inflammation and oxidative stress through regulating the miR-148a/Rcan2 axis in rats with AKI induced by sepsis. Therefore, CIRC-Ttc3 may be a potential therapeutic target for sepsis-induced AKI.

Loganin Attenuates Septic Acute Renal Injury with the Participation of AKT and Nrf2/HO-1 Signaling Pathways

Purpose

Sepsis, a destructive inflammatory response syndrome, is the principal reason to induce death in the intensive care unit. Loganin has been proved to possess the property of anti-inflammation, antioxidant, neuroprotection, and sedation. The primary aim of this study was to evaluate whether Loganin could alleviate acute kidney injury (AKI) during sepsis and investigate the latent mechanisms.

Methods

Septic AKI models were established by cecal ligation and puncture (CLP) surgery in mice and given Loganin (20, 40, 80 mg/kg) by gavage. Lipopolysaccharides (LPS)-stimulated human kidney proximal tubular (HK2) cells incubated in Loganin (5, 10, 20 μ M) were used to explore the accurate mechanisms. Survival rate, renal function (creatinine and blood urea nitrogen), and renal pathological changes were detected in septic mice. Oxidative stress markers (SOD, GSH-Px, MDA, and SOD), mitochondrial membrane potential, mitochondrial calcium overload, and nuclear factor E2-related factor 2 (Nrf2)/heme-oxygenase 1 (HO-1) pathway activation in vivo and in vitro were determined by commercial kits and Western blot. Cell apoptosis, apoptotic-related protein (cleaved caspase-3, Bcl-2, and Bax) expression and protein kinase B (AKT) phosphorylation in vivo and in vitro were measured by TUNEL staining and Western blot. Finally, AKT blockage by 10 μM LY294002 or Nrf2 inhibition by10 μ M ML385 were utilized to prove the involvement of AKT and Nrf2/HO-1 pathway in AKI during sepsis.

Results

We found Loganin treatment (20, 40, 80 mg/kg) mitigated septic AKI reflected by elevated renal function and palliative pathological changes. Oxidative stress and apoptosis in the kidney and LPS-treated HK2 cells were also inhibited by Loganin administration, which was accompanied by AKT and Nrf2/HO-1 pathway activation. Besides, the protective effects of Loganin could be diminished by AKT or Nrf2 blockage, indicating the involvement of AKT and Nrf2/HO-1 pathway.

Conclusion

The results suggested that the protective effects of Loganin on AKI during sepsis might be mediated by AKT and Nrf2/HO-1 pathway signaling activation in kidney proximal tubular cells.

MUC1 Mitigates Renal Injury and Inflammation in Endotoxin Induced Acute Kidney Injury by Inhibiting the TLR4-MD2 Axis and Reducing Pro-Inflammatory Macrophages Infiltration

ABSTRACT

Sepsis is the leading cause of acute kidney injury (AKI) in critical care patients. A cornerstone of sepsis-associated AKI is dysregulated inflammation driven by excessive activation of Toll-like receptor 4 (TLR4) pathway. MUC1, a membrane bound mucin expressed in both epithelial tubular cells and renal macrophages, has been shown to be involved in the regulation of TLRs. Therefore we hypothesized that MUC1 could mitigate the renal inflammatory response to TLR4 activation. To test this hypothesis, we used a murine model of endotoxin-induced AKI by intraperitoneal injection of lipopolysaccharide (LPS). We showed that Muc1-/- mice have a more severe renal dysfunction, an increased activation of the tissular NF-kB pathway and secreted more pro inflammatory cytokines compare to Muc1+/+ mice. By flow cytometry, we observed that the proportion of M1 (pro-inflammatory) macrophages in the kidneys of Muc1-/- mice was significantly increased. In human and murine primary macrophages, we showed that MUC1 is only induced in M1 type macrophages and that macrophages derived from Muc1-/- mice secreted more pro-inflammatory cytokines. Eventually, in HEK293 cells, we showed that (i) MUC1 cytosolic domain (CT) seems necessary for the negative regulation of TLR4 (ii) by proximity ligation assay, MUC1-CT is in close relationship with TLR4 and acts as a competitive inhibitor of the recruitment of MYD88. Overall our results support that in the context of endotoxin-induced AKI, MUC1 plays a significant role in controlling disease severity by regulating negatively the TLR4-MD2 axis.