Peroxiredoxin 1 aggravates acute kidney injury by promoting inflammation through Mincle/Syk/NF-κB signaling

Role of macrophages in peritoneal dialysis-associated peritoneal fibrosis

Peritoneal dialysis (PD) can be used as renal replacement therapy when chronic kidney disease (CKD) progresses to end-stage renal disease. However, peritoneal fibrosis (PF) is a major cause of PD failure. Studies have demonstrated that PD fluid contains a significantly larger numbers of macrophages compared with the healthy individuals. During PD, macrophages can secrete cytokines to keep peritoneal tissue in sustained low-grade inflammation, and participate in the regulation of fibrosis-related signaling pathways, such as NF-κB, TGF-β/Smad, IL4/STAT6, and PI3K/AKT. A series of basic pathological changes occurs in peritoneal tissues, including epithelial mesenchymal transformation, overgeneration of neovasculature, and abnormal deposition of extracellular matrix. This review focuses on the role of macrophages in promoting PF during PD, summarizes the targets of macrophage-related inhibition of fibrosis, and provides new ideas for clinical research on delaying PF, maintaining the function and integrity of peritoneum, prolonging duration of PD as a renal replacement modality, and achieving longer survival in CKD patients.

Innate immune cells in acute and chronic kidney disease

Acute kidney injury (AKI) and chronic kidney disease (CKD) are inter-related clinical and pathophysiological disorders. Cells of the innate immune system, such as granulocytes and macrophages, can induce AKI through the secretion of pro-inflammatory mediators such as cytokines, chemokines and enzymes, and the release of extracellular traps. In addition, macrophages and dendritic cells can drive the progression of CKD through a wide range of pro-inflammatory and pro-fibrotic mechanisms, and by regulation of the adaptive immune response. However, innate immune cells can also promote kidney repair after acute injury. These actions highlight the multifaceted nature of the way by which innate immune cells respond to signals within the kidney microenvironment, including interaction with the complement and coagulation cascades, cells of the adaptive immune system, intrinsic renal cells and infiltrating mesenchymal cells. The factors and mechanisms that underpin the ability of innate immune cells to contribute to renal injury or repair and to drive the progression of CKD are of great interest for understanding disease processes and for developing new therapeutic approaches to limit AKI and the AKI-to-CKD transition.

Curcumol Ameliorates Cisplatin-induced Nephrotoxicity by Targeting TAK1 and Inhibiting MAPK and NF-κB Pathways

BACKGROUND

Although cisplatin (Cis) is a foundational chemotherapeutic agent, its dose-limiting nephrotoxicity lacks clinically effective drugs. Curcumol (CUR), a bioactive sesquiterpenoid derived from Curcuma zedoariae rhizome, exhibits multi-organ protective effects. However, its therapeutic potential and molecular targets in Cis-provoked acute kidney injury (AKI) remain unexplored.

PURPOSE

This study systematically investigated the nephroprotection and underlying mechanism of CUR in Cis-induced nephrotoxicity.

METHODS

C57BL/6 mice received intraperitoneal administration of 20 mg/kg Cis to induce AKI. Dual-concentration CUR (40/80 mg/kg) was administered pre- and post-treatment in Cis-challenged mice, with longitudinal monitoring of renal function. Human tubular epithelial cells (HK-2 cells) were used to evaluate CUR's nephroprotection in vitro. RNA-sequencing transcriptomics identified pathway-level mechanisms, while structure-based molecular docking (MOD) prioritized target proteins.

RESULTS

CUR exhibited dose-responsive nephroprotection, reducing apoptosis, oxidative stress, and inflammation more effectively than N-acetylcysteine in pre- and post-Cis treatment regimens. Mechanistically, we revealed that nephroprotection of CUR primarily involves suppression of phosphorylation-mediated MAPK/NF-κB pathway activation, thereby mitigating the inflammatory response. Notably, MOD and Cellular thermal shift assay (CETSA) data suggested a direct interaction between CUR and TAK1. Functional validation experiments demonstrated that TAK1 silencing attenuated cisplatin-induced tubular cell injury, and TAK1 activity was essential for CUR's protective effects.

CONCLUSION

CUR ameliorated Cis-triggered AKI by targeting TAK1 and inhibiting MAPK and NF-κB pathways. These findings suggest that CUR may serve as a promising adjuvant to overcome the primary limitation of Cis.

Peroxiredoxin-1 aggravates hypoxia-induced renal injury by promoting inflammation through the TLR4/MAPK/NF-κB signaling pathway

Hypoxia can induce pathological alterations to the kidneys, such as activation of inflammatory signaling pathways. This form of inflammation is pathogen-free and is referred to as aseptic inflammation. Currently, the mechanisms leading to aseptic inflammation under hypoxia are not well understood. Emerging evidence has indicated that Prdx1, a member of the peroxidase family, contributes to the development of various diseases by stimulating aseptic inflammation. This study was conducted to reveal the potential role of Prdx1 in the pathogenesis of hypoxia-induced renal injury. A mouse model of systemic hypoxia was developed, which revealed that Prdx1 levels were elevated in injured kidneys and peripheral circulation. A comparable increase was also observed in hypoxia-treated immortalized bone marrow-derived macrophages (iBMDMs). Knock-down of Prdx1 in mice caused a significant reduction in renal tissue injury and inflammation induced by hypoxic injury. In addition, we demonstrated that Prdx1 modulates inflammatory responses by activating the TLR4/MAPK/NF-κB signaling pathways. Recombinant Prdx1 promoted the activation of these pathways in macrophages, whereas genetic knockout of Prdx1 or pharmacological inhibition suppressed their activity. Altogether, we found a previously unrecognized role for Prdx1 in the regulation of inflammation in hypoxia-induced renal injury. These findings suggest that Prdx1 can be a potential target for treating this severe disease.

KDM6A Deficiency Induces Myeloid Bias and Promotes CMML-Like Disease Through JAK/STAT3 Activation by Repressing SOCS3

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy with a poor prognosis and limited targeted therapies. Lysine demethylase 6A (KDM6A), a H3K27 demethylase and key component of the COMPASS complex, is frequently mutated in hematologic malignancies, but its roles in embryonic hematopoiesis and tumor suppression in CMML remain unclear. Using zebrafish models with kdm6a mutants and integrative multi-omics analysis (ATAC-seq, RNA-seq, ChIP), we find that Kdm6a is a critical positive regulator of hematopoietic stem and progenitor cell (HSPC) emergence via Syk-related inflammatory signaling in a H3K27me3-dependent manner. We further find that Kdm6a haploinsufficiency in zebrafish leads to myeloid-biased hematopoiesis and a CMML-like disease, similar to CMML patients with reduced KDM6A expression. This KDM6A haploinsufficiency also significantly alters the chromatin landscape of genes associated with aging and cellular homeostasis in HSPCs. Mechanistically, KAM6A haploinsufficiency represses SOCS3 expression, thereby activating JAK/STAT3 signaling in HSPCs. Importantly, inhibitors targeting JAK or STAT3 phosphorylation alleviate myeloid expansion, providing a rationale for JAK/STAT pathway inhibition in CMML therapy. These findings enhance our understanding of CMML pathogenesis and propose new therapeutic avenues.

Theabrownins improve burn-induced kidney injury by increasing the levels of guanidinoacetic acid and fumaric acid

BACKGROUND

Burns are a common and serious health issue, with severe burn-induced acute kidney injury (AKI) being a major factor contributing to poor recovery and increased mortality in patients. Theabrownins (TBs), bioactive compounds formed during tea leaf fermentation, have shown promising effects on reducing inflammation, combating oxidative stress, and enhancing metabolic function. However, the roles and mechanisms of TBs in burn-induced kidney injury are still not fully understood.

METHODS

The dorsal skin of 3-month-old mice was exposed to hot water for 10 s to induce burn-related renal injury. The mice were then orally administered TBs (40 mg/kg and 400 mg/kg). After 24 h of treatment, the mice were sacrificed for tissue collection. Transcriptomic and metabolomic analyses were performed to identify the pathways modulated by TBs. Metabolomics revealed TB-associated renal metabolites, such as guanidinoacetic acid (GAA) and fumaric acid (FA). Renal tubular epithelial (HK2) cells pretreated with GAA and FA were exposed to hydrogen peroxide (H2O2), cisplatin (CDDP) and erastin to establish a cell injury model. Changes in the levels of relevant molecules were assessed using quantitative RT-PCR, Western blotting, and fluorescence staining.

RESULTS

TB treatment significantly increased the survival rate and reduced kidney injury in mice with burn injury. Multiomics analyses and molecular experimental validation revealed that TB treatment downregulated the inflammation, apoptosis, and ferroptosis pathways in the kidneys of mice with burn injury and increased the levels of the renal metabolites GAA and FA. Cellular experiments confirmed that GAA and FA alleviated H2O2-, CDDP- and erastin-induced renal tubular epithelial cell injury by inhibiting apoptosis and ferroptosis.

CONCLUSIONS

Burns induce inflammation and kidney damage by upregulating the apoptosis and ferroptosis pathways in renal tissue. TBs alleviate burn-induced renal apoptosis and ferroptosis by increasing the levels of GAA and FA in the kidneys, thereby ameliorating kidney damage. This study innovatively and systematically evaluated the ability of TBs to ameliorate burn-induced kidney injury and, for the first time, identified the potential mechanism by which TBs ameliorate burn-induced kidney damage by increasing the levels of the metabolites GAA and FA in the kidneys.

Macrophage-Derived Type 1 IFN, Renal Tubular Epithelial Cell Polyploidization, and AKI-to-CKD Transition

Key Points

Macrophage-derived IFN-β contributes to tubular epithelial cell polyploidization after AKI. IFN-β induced tubular epithelial cell polyploidization by regulating inorganic pyrophosphatase-mediated yes-associated protein (YAP) dephosphorylation. Delayed blockade of the IFN-β response attenuated persistent polyploidization and kidney fibrosis.

Background

AKI is recognized as a common risk factor of CKD. Renal tubular epithelial cell polyploidization after AKI is closely associated with maladaptive repair, while the regulatory and molecular mechanisms remain poorly understood. In this study, we set out to investigate the mechanism of tubular epithelial cell polyploidization and their role in AKI-to-CKD transition.

Methods

The change characters of polyploid tubular epithelial cells and macrophages after AKI were detected by flow cytometry and immunofluorescence. The underlying mechanism was explored by RNA-sequencing analysis, immunofluorescence, and Western blot. The role of tubular epithelial cell polyploidization in AKI-to-CKD transition was evaluated by transgenic mice and drug interventions.

Results

We discovered that tubular epithelial cells underwent polyploidization after AKI, and polyploid tubular epithelial cells exhibited greater fibrotic phenotypes than nonpolyploid cells. Furthermore, we revealed an upregulated IFN-β response feature within tubular epithelial cells after AKI and identified that macrophage-derived IFN-β bound to IFN-I receptor 1 of tubular epithelial cells and induced their polyploidization. Mechanistically, IFN-β , secreted by macrophages through activation of the cyclic guanosine monophosphate-AMP synthase-stimulator of IFN genes pathway, acted on tubular epithelial cells and facilitated inorganic pyrophosphatase binding to yes-associated protein (YAP), which mediated YAP dephosphorylation and subsequent nuclear translocation, culminating in p21 expression and polyploidization. Importantly, delayed blockade of the IFN-β response and pharmacological inhibition of stimulator of IFN genes or YAP activation on day 4 after AKI significantly attenuated persistent tubular epithelial cell polyploidization and AKI-induced kidney fibrosis.

Conclusions

Macrophage-derived IFN-β contributed to tubular epithelial cell polyploidization by regulating inorganic pyrophosphatase/YAP signaling pathway–mediated p21 expression and further promoted AKI-to-CKD transition.

NFĸB and its inhibitors in preeclampsia: mechanisms and potential interventions

Preeclampsia (PE), which affects between 2 and 15% of pregnancies, is one of the most often reported prenatal problems. It is defined as gestational hypertension beyond 20 weeks of pregnancy, along with widespread edema or proteinuria and specific types of organ damage. PE is characterized by increased levels and activation of nuclear factor kappa B (NF-κB) in the mother's blood and placental cells. This factor controls over 400 genes linked to inflammatory, apoptotic, angiogenesis, and cellular responses to hypoxia and oxidative stress. In the final stages of physiological pregnancy, NF-κB levels need to be lowered to favor maternal immunosuppressive events and continue gestation to prevent hypoxia and inflammation, which are advantageous for implantation. Pharmacotherapy is thought to be a potential treatment for PE by downregulating NF-κB activation. NF-κB activity has been discovered to be regulated by several medications used for both prevention and treatment of PE. However, in order to guarantee treatment safety and effectiveness, additional creativity is desperately required. This article provides an overview of the current understanding of the defined function of NF-κB in PE progression. According to their effect on the cellular control of NF-κB pathways, newly proposed compounds for preventing and treating PE have also been emphasized.

Regulated cell death and DAMPs as biomarkers and therapeutic targets in normothermic perfusion of transplant organs. Part 1: their emergence from injuries to the donor organ

This Part 1 of a bipartite review commences with a succinct exposition of innate alloimmunity in light of the danger/injury hypothesis in Immunology. The model posits that an alloimmune response, along with the presentation of alloantigens, is driven by DAMPs released from various forms of regulated cell death (RCD) induced by any severe injury to the donor or the donor organ, respectively. To provide a strong foundation for this review, which examines RCD and DAMPs as biomarkers and therapeutic targets in normothermic regional perfusion (NRP) and normothermic machine perfusion (NMP) to improve outcomes in organ transplantation, key insights are presented on the nature, classification, and functions of DAMPs, as well as the signaling mechanisms of RCD pathways, including ferroptosis, necroptosis, pyroptosis, and NETosis. Subsequently, a comprehensive discussion is provided on major periods of injuries to the donor or donor organs that are associated with the induction of RCD and DAMPs and precede the onset of the innate alloimmune response in recipients. These periods of injury to donor organs include conditions associated with donation after brain death (DBD) and donation after circulatory death (DCD). Particular emphasis in this discussion is placed on the different origins of RCD-associated DAMPs in DBD and DCD and the different routes they use within the circulatory system to reach potential allografts. The review ends by addressing another particularly critical period of injury to donor organs: their postischemic reperfusion following implantation into the recipient-a decisive factor in determining transplantation outcome. Here, the discussion focuses on mechanisms of ischemia-induced oxidative injury that causes RCD and generates DAMPs, which initiate a robust innate alloimmune response.

Pyroptosis in sepsis-associated acute kidney injury: mechanisms and therapeutic perspectives

Sepsis-associated acute kidney injury (S-AKI) is a severe complication characterized by high morbidity and mortality, driven by multi-organ dysfunction. Recent evidence suggests that pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, plays a critical role in the pathophysiology of S-AKI. This review examines the mechanisms of pyroptosis, focusing on inflammasome activation (e.g., NLRP3), caspase-mediated processes, and the role of Gasdermin D in renal tubular damage. We also discuss the contributions of inflammatory mediators, oxidative stress, and potential therapeutic strategies targeting pyroptosis, including inflammasome inhibitors, caspase inhibitors, and anti-inflammatory therapies. Lastly, we highlight the clinical implications and challenges in translating these findings into effective treatments, underscoring the need for personalized medicine approaches in managing S-AKI.

SARS-CoV-2 nucleocapsid protein induces a Mincle-dependent macrophage inflammatory response in acute kidney injury

BACKGROUND

Although the COVID-19 pandemic has receded, the SARS-CoV-2 virus still poses a significant threat to individuals with pre-existing renal conditions, leading to severe acute kidney injury (AKI). However, the underlying mechanisms remain poorly understood.

METHODS

In this study, we used ultrasound microbubble technology to transfect and overexpress the SARS-CoV-2 nucleocapsid (N) protein in the kidneys of IRI (ischemia-reperfusion injury) and Cis (cisplatin) induced AKI mice. Additionally, we generated macrophage-specific Mincle knockout mice to investigate the amplifying effects of the SARS-CoV-2 N protein on AKI renal injury and the critical regulatory role of macrophage inducible C-type lectin (Mincle). Finally, we employed Mincle-neutralizing antibodies to intervene in the SARS-CoV-2 N-induced exacerbation of kidney injury in AKI.

RESULTS

We found that the specific overexpression of the SARS-CoV-2 N protein significantly aggravates kidney injury in the context of AKI. Mechanistically, we found that the exacerbation of acute kidney injury by the SARS-CoV-2 N protein is dependent on Mincle, as the SARS-CoV-2 N protein activates Mincle to enhance the Syk/NF-κB signaling pathway, leading to damage and inflammation of renal tubular epithelial cells. This was confirmed in Mincle knockout mice and cells, where Mincle knockout alleviated the renal tubular injury and inflammation caused by SARS-CoV-2 N transfection. Importantly, the use of anti-Mincle neutralizing antibodies could effectively mitigate the acute kidney injury exacerbated by the SARS-CoV-2 N protein.

CONCLUSIONS

In summary, we identified the SARS-CoV-2 N protein as a key mediator of kidney injury in AKI and demonstrated that it exacerbates the injury through a Mincle-dependent mechanism. Targeting Mincle may represent a novel therapeutic strategy for treating COVID-19-related acute kidney injury.

Macrophage WEE1 Directly Binds to and Phosphorylates NF-κB p65 Subunit to Induce Inflammatory Response and Drive Atherosclerosis

Atherosclerosis has an urgent need for new therapeutic targets. Protein kinases orchestrate multiple cellular events in atherosclerosis and may provide new therapeutic targets for atherosclerosis. Here, a protein kinase, WEE1 G2 checkpoint kinase (WEE1), promoting inflammation in atherosclerosis is identified. Kinase enrichment analysis and experimental evidences reveal macrophage WEE1 phosphorylation at S642 in human and mouse atherosclerotic tissues. RNA-seq analysis, combined with experiment studies using mutant WEE1 plasmids, shows that WEE1 phosphorylation, rather than WEE1 expression, mediated oxLDL-induced inflammation in macrophages. Macrophage-specific deletion of WEE1 or pharmacological inhibition of WEE1 kinase activity attenuates atherosclerosis by reducing inflammation in mice. Mechanistically, RNA-seq and co-immunoprecipitation followed by proteomics analysis are used to explore the mechanism and substrate of WEE1. p-WEE1 promoted inflammatory response through activating NF-κB shown and further revealed that WEE1 can directly bind to the p65 subunit. It is confirmed that p-WEE1 directly interacts with the RHD domain of p65 and phosphorylates p65 at S536, thereby facilitating subsequent NF-κB activation and inflammatory response in macrophages. The findings demonstrate that macrophage WEE1 drives NF-κB activation and atherosclerosis by directly phosphorylating p65 at S536. This study identifies WEE1 as a new upstream kinase of p65 and a potential therapeutic target for atherosclerosis.

PRDX1 affects acrylamide-induced neural damage through the PTEN/AKT signaling pathway

Peroxiredoxin 1 (PRDX1) is a member of the peroxidase family of antioxidant enzymes. However, the role and mechanism of PRDX1 in acrylamide (ACR)-induced nerve damage have not been reported. We used SD rats and well-differentiated rat pheochromocytoma cells (PC-12 cells) to established in vivo and in vitro models of ACR. Immunohistochemistry, immunofluorescence and RT-qPCR experiments were used to detect the expression of PRDX1 in neurons of rat hippocampal tissue. The ultrastructural changes of neurons and PC-12 cells in rat hippocampal tissue were observed under transmission electron microscope. Western blot detected the protein expression levels of PRDX1, PTEN, AKT and p-AKT. In vivo and in vitro experimental results showed that PRDX1 showed a significant up-regulation trend after ACR exposure (p < 0.05). In vitro experiments showed that after inhibiting PRDX1 expression with PRDX1 siRNA, the survival rate of PC-12 cells significantly increased, and the damage to cell morphology and organelles was markedly improved. Western blot analysis revealed that ACR exposure can cause a significant increase in PTEN protein expression level and p-AKT/AKT protein ratio (p < 0.05). After inhibiting the expression of PRDX1, the protein expression level of PTEN and the protein ratio of p-AKT/AKT were significantly reduced, while the protein levels of SYN1 and BDNF were significantly increased (p < 0.05). This study, for the first time, demonstrates that PRDX1 affects ACR-induced neurotoxicity by regulating the PTEN/AKT signaling pathway. And, provides novel insights into the prevention and treatment of neurotoxicity in populations exposed to ACR.

Deletion of Pyruvate Carboxylase in Tubular Epithelial Cell Promotes Renal Fibrosis by Regulating SQOR/cGAS/STING-Mediated Glycolysis

Renal fibrosis is a common pathway involved in the progression of various chronic kidney diseases to end-stage renal disease. Recent studies show that mitochondrial injury of renal tubular epithelial cells (RTECs) is a crucial pathological foundation for renal fibrosis. However, the underlying regulatory mechanisms remain unclear. Pyruvate carboxylase (PC) is a catalytic enzyme located within the mitochondria that is intricately linked with mitochondrial damage and metabolism. In the present study, the downregulation of PC in various fibrotic animal and human kidney samples is demonstrated. Renal proximal tubule-specific Pcx gene knockout mice (PcxcKO) has significant interstitial fibrosis compared to control mice, with heightened expression of extracellular matrix molecules. This is further demonstrated in a stable PC knock-out RTEC line. Mechanistically, PC deficiency reduces its interaction with sulfide:quinone oxidoreductase (SQOR), increasing the ubiquitination and degradation of SQOR. This leads to mitochondrial morphological and functional disruption, increased mtDNA release, activation of the cGAS-STING pathway, and elevated glycolysis levels, and ultimately, promotes renal fibrosis. This study investigates the molecular mechanisms through which PC deficiency induces mitochondrial injury and metabolic reprogramming in RTECs. This study provides a novel theoretical foundation and potential therapeutic targets for the pathogenesis and treatment of renal fibrosis.

Macrophage-driven inflammation in acute kidney injury: Therapeutic opportunities and challenges

Acute kidney injury (AKI) is increasingly being recognized as a systemic disorder associated with significant morbidity and mortality. AKI manifests with extensive cellular damage, necrosis, and an intense inflammatory response, often leading to late-stage interstitial fibrosis. Although the mechanisms underlying renal injury and repair remain poorly understood, macrophages (pivotal inflammatory cells) play central roles in AKI. They undergo polarization into pro-inflammatory and anti-inflammatory phenotypes, contributing dynamically to both the injury and repair processes while maintaining homeostasis. Macrophages modulate microenvironmental inflammation by releasing extracellular vesicles (EVs) containing pro- or anti-inflammatory signaling molecules, thereby influencing the regulation of tissue injury. The injured tissue cells release EVs and activate local macrophages to initiate these responses. Our bibliometric analysis indicated that a shift has occurred in AKI macrophage research towards therapeutic strategies and clinical translation, focusing on macrophage-targeted therapies, including exosomes and nanoparticles. This review highlights the roles and mechanisms of macrophage activation, phenotypic polarization, and trans-differentiation in AKI and discusses macrophage-based approaches for AKI prevention and treatment. Understanding the involvement of macrophages in AKI contributes to the comprehension of related immune mechanisms and lays the groundwork for novel diagnostic and therapeutic avenues.

Cardiorenal protective effects of Tanhuo decoction in acute myocardial infarction via regulating multi-target inflammation and metabolic signaling pathways

Introduction

Inflammation is a key driver of adverse outcomes in acute myocardial infarction (AMI), yet current western anti-inflammatory therapies are limited by their single-target nature and side effects. Traditional Chinese medicine (TCM), such as Tanhuo Decoction (THD), offers a multi-target, low-toxicity alternative.

Methods

In a randomized controlled trial, AMI patients with high inflammatory responses received either standard Western medicine (WM) alone or combined with THD for 3 days. Clinical outcomes and inflammatory markers were assessed, and proteomic and network pharmacology analyses were performed.

Results

The THD + WM group showed significant reductions in neutrophil counts and hs-CRP levels, along with improved creatinine clearance rate (CCR), compared to WM alone. Proteomic analysis revealed downregulation of pro-inflammatory proteins (PTX3, IL-18, TNFRSF11A) and upregulation of the anti-inflammatory IL1RL2. THD also modulated lipid metabolism and insulin sensitivity pathways.

Discussions

THD enhances the anti-inflammatory and metabolic benefits of standard AMI therapy through multi-target pathway regulation. These findings support its integration into modern cardiovascular care, particularly for patients with high inflammatory and metabolic risk.

DKS26 Alleviates Ischemia-Reperfusion Injury-Induced Acute Kidney Injury by Stabilizing Vitamin D Receptors to Inhibit the Inflammatory Pathway of NF-κB P65

Acute kidney injury (AKI) is a common critical clinical disease with high morbidity and mortality rates. Ischemia-reperfusion (IR) is the main cause of AKI, and there is no effective treatment or prevention. Therefore, it is critical to screen for effective therapeutic agents and to find therapeutic targets. DKS26 is a derivative of oleanolic acid (OA) optimized for bioavailability while retaining the anti-inflammatory, antioxidant, and anti-apoptotic properties of OA. This study aimed to investigate the therapeutic effects of DKS26 on AKI and its underlying molecular mechanisms. We established an AKI model in vivo and in vitro and observed that DKS26 had an ameliorative effect on IR or H/R-induced renal tubular epithelial cell injury and reduced oxidative stress, inflammation, and apoptosis. Meanwhile, Swiss TargetPrediction and AutoDock Vina analysis revealed that DKS26 may interact with vitamin D receptors (VDR) through hydrogen bonding, suggesting that DKS26 may exert effects through VDR. In this study, we found that DKS26 treatment enhanced the stability of the VDR protein, promoted the binding of VDR to p-NF-κB P65Ser311, reduced the entry of p-NF-κB P65Ser311 into the nucleus, and inhibited the transcription of downstream inflammatory genes as well as their own expression, thus exerting its protective effect. In summary, these findings suggest that DKS26 may be a promising preventive strategy and provide a theoretical and experimental basis for AKI treatment.

Metabolomics- and proteomics-based multi-omics integration reveals early metabolite alterations in sepsis-associated acute kidney injury

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) is a frequent complication in patients with sepsis and is associated with high mortality. Therefore, early recognition of SA-AKI is essential for administering supportive treatment and preventing further damage. This study aimed to identify and validate metabolite biomarkers of SA-AKI to assist in early clinical diagnosis.

METHODS

Untargeted renal proteomic and metabolomic analyses were performed on the renal tissues of LPS-induced SA-AKI and sepsis mice. Glomerular filtration rate (GFR) monitoring technology was used to evaluate real-time renal function in mice. To elucidate the distinctive characteristics of SA-AKI, a multi-omics Spearman correlation network was constructed integrating core metabolites, proteins, and renal function. Subsequently, metabolomics analysis was used to explore the dynamic changes of core metabolites in the serum of SA-AKI mice at 0, 8, and 24 h. Finally, a clinical cohort (28 patients with SA-AKI vs. 28 patients with sepsis) serum quantitative metabolomic analysis was carried out to build a diagnostic model for SA-AKI via logistic regression (LR).

RESULTS

Thirteen differential renal metabolites and 112 differential renal proteins were identified through a multi-omics study of SA-AKI mice. Subsequently, a multi-omics correlation network was constructed to highlight five core metabolites, i.e., 3-hydroxybutyric acid, 3-hydroxymethylglutaric acid, creatine, myristic acid, and inosine, the early changes of which were then observed via serum time series experiments of SA-AKI mice. The levels of 3-hydroxybutyric acid, 3-hydroxymethylglutaric acid, and creatine increased significantly at 24 h, myristic acid increased at 8 h, while inosine decreased at 8 h. Ultimately, based on the identified core metabolites, we recruited 56 patients and constructed a diagnostic model named IC3, using inosine, creatine, and 3-hydroxybutyric acid, to early identify SA-AKI (AUC = 0.90).

CONCLUSIONS

We proposed a blood metabolite model consisting of inosine, creatine, and 3-hydroxybutyric acid for the early screening of SA-AKI. Future studies will observe the performance of these metabolites in other clinical populations to evaluate their diagnostic role.

Novel Glycyrrhetin Ureas Possessing 2-Hydroxy-3-enone A Ring: Modification, Anti-inflammatory Activity, and Targeted STING for the Remedy of Acute Kidney Injury

Glycyrrhetin urea has emerged as a privileged scaffold with anti-inflammatory activity for the treatment and prevention of acute kidney injury (AKI). In this study, structural modifications of the A ring of glycyrrhetinic acid yielded a series of urea derivatives, among which compound 7o exhibited the most promising anti-inflammatory activity. 7o was confirmed to interact with STING through a cellular heat shift assay and to inhibit the STING/NF-κB pathway in RAW264.7 cells. It acted on the STING pathway, inhibited NF-κB phosphorylation, and subsequently reduced the level of release of inflammatory factors. Additionally, 7o significantly increased the survival rate of renal tubular epithelial cells, demonstrating a protective effect against cisplatin-induced cell death and mitigating inflammation activation. The in vivo AKI mouse model showed that 7o significantly downregulated serum creatinine (Scr), blood urea nitrogen (BUN), and levels of inflammatory factors (IL-1β, IL-6, and TNF-α), thereby improving renal function. Morphological analysis revealed that 7o attenuated the cisplatin-induced renal tubular injury. Therefore, 7o represents a promising lead for the prevention and treatment of AKI.

Lymphocytes and innate immune cells in acute kidney injury and repair

Acute kidney injury (AKI) is a common and serious disease entity that affects native kidneys and allografts but for which no specific treatments exist. Complex intrarenal inflammatory processes driven by lymphocytes and innate immune cells have key roles in the development and progression of AKI. Many studies have focused on prevention of early injury in AKI. However, most patients with AKI present after injury is already established. Increasing research is therefore focusing on mechanisms of renal repair following AKI and prevention of progression from AKI to chronic kidney disease. CD4+ and CD8+ T cells, B cells and neutrophils are probably involved in the development and progression of AKI, whereas regulatory T cells, double-negative T cells and type 2 innate lymphoid cells have protective roles. Several immune cells, such as macrophages and natural killer T cells, can have both deleterious and protective effects, depending on their subtype and/or the stage of AKI. The immune system not only participates in injury and repair processes during AKI but also has a role in mediating AKI-induced distant organ dysfunction. Targeted manipulation of immune cells is a promising therapeutic strategy to improve AKI outcomes.

Tyrobp deficiency blocks NLRP3-mediated inflammation and pyroptosis to alleviate myocardial ischemia-reperfusion injury through regulating Syk

PURPOSE

The present study aims to investigate the biological function of Tyrobp in myocardial ischemia-reperfusion injury (MIRI) and to clarify its potential reaction mechanisms.

METHODS

AC16 cells were induced by oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate the MIRI in vitro. The cell transfection technology was used to downregulate Tyrobp, followed by assessment of cell damage, apoptosis and cytokines production via Cell Counting Kit (CCK)-8 assay, lactate dehydrogenase (LDH) release assay, TUNEL and ELISA assays, respectively. Immunofluorescence assay was performed to assess GSDMD. Corresponding proteins were detected via western blotting, and Co-immunoprecipitation (Co-IP) assay was used to validate proteins interaction.

RESULTS

Tyrobp was upregulated in OGD/R-exposed AC16 cells, and Tyrobp deficiency significantly alleviated OGD/R-caused cell viability loss, LDH release and cell apoptosis in AC16 cells. Meanwhile, Tyrobp deficiency inhibited the activation of NLRP3 inflammasome, reduced the production of cytokines and inhibited GSDMD intensity and GSDMD-N expression. Additionally, Tyrobp could interact with Syk and regulate Syk/NF-κB signaling. The rescue experiments showed that the above effects of Tyrobp deficiency on OGD/R-exposed AC16 cells were partly weakened by Syk overexpression.

CONCLUSION

Tyrobp deficiency alleviated MIRI by inhibiting NLRP3-mediated inflammation and pyroptosis through regulating Syk, providing a novel target for the treatment of MIRI.

Remifentanil represses oxidative stress to relieve hepatic ischemia/reperfusion injury via regulating BACH1/PRDX1 axis

BACKGROUND

Hepatic ischemia-reperfusion injury (HIRI) is a major cause of liver dysfunction after clinical liver surgery, which seriously affects the prognosis of patients. Remifentanil (RE) has been verified to attenuate HIRI. However, its therapeutic mechanism is still unclear. This study aimed to explore the protective mechanism of RE against HIRI.

METHODS

A mouse HIRI model and an in vitro model of hypoxia/reoxygenation (H/R)-stimulated AML12 hepatocytes were established. Liver histopathological changes were evaluated by hematoxylin and eosin (HE) staining. Oxidative stress damage was assessed by malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) levels. Liver function was determined by serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH). and adenosine triphosphate (ATP) levels. Cell counting kit-8 (CCK-8) assessed cell viability. Apoptosis was measured by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) and flow cytometry. The levels of inflammatory factors were detected by enzyme-linked immunosorbent assay (ELISA) kits. The differentially expressed genes were evaluated by mRNA microarray analysis. Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR) were conducted to detect molecule expression. The binding of BTB and CNC homology 1 (BACH1) to peroxiredoxin 1 (PRDX1) was validated by chromatin immunoprecipitation (ChIP) and dual luciferase reporter assay.

RESULTS

RE treatment improved liver function, and repressed oxidative stress damage and apoptosis in HIRI mice. Nine differentially expressed genes in the liver tissues of HIRI mice were selected by microarray analysis, among which BACH1 was down-regulated and PRDX1 was up-regulated after RE treatment. In addition, BACH1 directly bound to the promoter region of PRDX1 to inhibit its transcription and expression, which led to oxidative stress injury. BACH1 overexpression or PRDX1 silencing could counteract the beneficial effects of RE against HIRI.

CONCLUSION

RE suppressed oxidative stress injury and inflammation via inactivation of the BACH1/PRDX1 axis, thereby ameliorating HIRI. Our findings enrich the understanding of the protective mechanisms of RE against HIRI, and provide novel evidence for its clinical application.

Mefunidone alleviates silica-induced inflammation and fibrosis by inhibiting the TLR4-NF-κB/MAPK pathway and attenuating pyroptosis in murine macrophages

AIMS

Silicosis is the most common and severe type of pneumoconiosis, imposing a substantial disease burden and economic loss on patients and society. The pathogenesis and key targets of silicosis are not yet clear, and there are currently no effective treatments available. Therefore, we conducted research on mefunidone (MFD), a novel antifibrotic drug, to explore its efficacy and mechanism of action in murine silicosis.

METHODS

Acute 7-day and chronic 28-day silicosis models were constructed in C57BL/6J mice by the intratracheal instillation of silica and subsequently treated with MFD to assess its therapeutic potential. The effects of MFD on silica-induced inflammation, pyroptosis, and fibrosis were further investigated using immortalized mouse bone marrow-derived macrophages (iBMDMs).

RESULTS

In the 7-day silica-exposed mouse models, MFD treatment significantly alleviated pulmonary inflammation and notably reduced macrophage infiltration into the lung tissue. RNA-sequencing analysis of silica-induced iBMDMs followed by gene set enrichment analysis revealed that MFD profoundly influenced cytokine-cytokine receptor interactions, chemokine signaling, and the toll-like receptor signaling pathways. MFD treatment also markedly reduced the secretion of inflammatory cytokines and chemokines from silica-exposed iBMDMs. Moreover, MFD effectively downregulated the activation of the TLR4-NF-κB/MAPK signaling pathway induced by silica and mitigated the upregulation of pyroptosis markers. Additionally, MFD treatment significantly suppressed the activation of fibroblasts and alveolar epithelial cells co-cultured with silica-exposed mouse macrophages. Ultimately, in the 28-day silica-exposed mouse models, MFD administration led to a substantial reduction in the severity of pulmonary fibrosis.

CONCLUSION

MFD mitigates silica-induced pulmonary inflammation and fibrosis in mice by suppressing the TLR4-NF-κB/MAPK signaling pathway and reducing pyroptotic responses in macrophages. MFD could potentially emerge as a novel therapeutic agent for the treatment of silicosis.

Mincle receptor in macrophage and neutrophil contributes to the unresolved inflammation during the transition from acute kidney injury to chronic kidney disease

Background

Recent studies have demonstrated a strong association between acute kidney injury (AKI) and chronic kidney disease (CKD), while the unresolved inflammation is believed to be a driving force for this chronic transition process. As a transmembrane pattern recognition receptor, Mincle (macrophage-inducible C-type lectin, Clec4e) was identified to participate in the early immune response after AKI. However, the impact of Mincle on the chronic transition of AKI remains largely unclear.

Methods

We performed single-cell RNA sequencing (scRNA-seq) with the unilateral ischemia-reperfusion (UIR) murine model of AKI at days 1, 3, 14 and 28 after injury. Potential effects and mechanism of Mincle on renal inflammation and fibrosis were further validated in vivo utilizing Mincle knockout mice.

Results

The dynamic expression of Mincle in macrophages and neutrophils throughout the transition from AKI to CKD was observed. For both cell types, Mincle expression was significantly up-regulated on day 1 following AKI, with a second rise observed on day 14. Notably, we identified distinct subclusters of Minclehigh neutrophils and Minclehigh macrophages that exhibited time-dependent influx with dual peaks characterized with remarkable pro-inflammatory and pro-fibrotic functions. Moreover, we identified that Minclehigh neutrophils represented an "aged" mature neutrophil subset derived from the "fresh" mature neutrophil cluster in kidney. Additionally, we observed a synergistic mechanism whereby Mincle-expressing macrophages and neutrophils sustained renal inflammation by tumor necrosis factor (TNF) production. Mincle-deficient mice exhibited reduced renal injury and fibrosis following AKI.

Conclusion

The present findings have unveiled combined persistence of Minclehigh neutrophils and macrophages during AKI-to-CKD transition, contributing to unresolved inflammation followed by fibrosis via TNF-α as a central pro-inflammatory cytokine. Targeting Mincle may offer a novel therapeutic strategy for preventing the transition from AKI to CKD.

Rodent models of AKI and AKI-CKD transition: an update in 2024

Despite known drawbacks, rodent models are essential tools in the research of renal development, physiology, and pathogenesis. In the past decade, rodent models have been developed and used to mimic different etiologies of acute kidney injury (AKI), AKI to chronic kidney disease (CKD) transition or progression, and AKI with comorbidities. These models have been applied for both mechanistic research and preclinical drug development. However, current rodent models have their limitations, especially since they often do not fully recapitulate the pathophysiology of AKI in human patients, and thus need further refinement. Here, we discuss the present status of these rodent models, including the pathophysiologic compatibility, clinical translational significance, key factors affecting model consistency, and their main limitations. Future efforts should focus on establishing robust models that simulate the major clinical and molecular phenotypes of human AKI and its progression.

Characterization of macrophages in ischemia-reperfusion injury-induced acute kidney injury based on single-cell RNA-Seq and bulk RNA-Seq analysis

Acute kidney injury (AKI) is a complex disease, with macrophages playing a vital role in its progression. However, the mechanism of macrophage function remains unclear and strategies targeting macrophages in AKI are controversial. To address this issue, we used single-cell RNA-seq analysis to identify macrophage sub-types involved in ischemia-reperfusion-induced AKI, and then screened for associated hub genes using intersecting bulk RNA-seq data. The single-cell and bulk RNA-seq datasets were obtained from the Gene Expression Omnibus (GEO) database. Screening of differentially-expressed genes (DEGs) and pseudo-bulk DEG analyses were used to identify common hub genes. Pseudotime and trajectory analyses were performed to investigate the progression of cell differentiation. CellChat analysis was performed to reveal the crosstalk between cell clusters. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were used to identify enriched pathways in the cell clusters. Immunofluorescence and RT-PCR were preformed to validate the expression of the identified hub genes. Four hub genes, Vim, S100a6, Ier3, and Ccr1, were identified in the infiltrated macrophages between normal samples and those 3 days after ischemia-reperfusion renal injury (IRI); all were associated with the progression of IRI-induced AKI. Increased expression of Vim, S100a6, Ier3, and Ccr1 in infiltrated macrophages may be associated with inflammatory responses and may mediate crosstalk between macrophages and renal tubular epithelial cells under IRI conditions. Our results reveal that Ier3 may be critical in AKI, and that Vim, S100a6, Ier3, and Ccr1 may act as novel biomarkers and potential therapeutic targets for IRI-induced AKI.

Peroxiredoxin-1 as a molecular chaperone that regulates glutathione S-transferase P1 activity and drives mutidrug resistance in ovarian cancer cells

Ovarian cancer is among the most prevalent gynecological malignancies around the globe. Nonetheless, chemoresistance continues to be one of the greatest obstacles in the treatment of ovarian cancer. Therefore, understanding the mechanisms of chemoresistance and identifying new treatment options for ovarian cancer patients is urgently required. In this study, we found that the mRNA and protein expression levels of PRDX1 were significantly increased in cisplatin resistant A2780/CDDP cells. Cell survival assays revealed that PRDX1 depletion substantially increased ovarian cancer cell sensitivity to cisplatin, docetaxel, and doxorubicin. Additionally, PRDX1 significantly increased GSTP1 activity, resulting in multidrug resistance. Biochemical experiments showed that PRDX1 interacted with GSTP1 through Cysteine 83, which regulated GSTP1 activity as well as chemotherapy resistance in ovarian cancer cells. Our findings indicate that the molecular chaperone activity of PRDX1 is a promising new therapeutic target for ovarian cancer.