Identification of a Novel ECM Remodeling Macrophage Subset in AKI to CKD Transition by Integrative Spatial and Single-Cell Analysis

The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is a critical clinical issue. Although previous studies have suggested macrophages as a key player in promoting inflammation and fibrosis during this transition, the heterogeneity and dynamic characterization of macrophages are still poorly understood. Here, we used integrated single-cell RNA sequencing and spatial transcriptomic to characterize the spatiotemporal heterogeneity of macrophages in murine AKI-to-CKD model of unilateral ischemia-reperfusion injury. A marked increase in macrophage infiltration at day 1 was followed by a second peak at day 14 post AKI. Spatiotemporal profiling revealed that injured tubules and macrophages co-localized early after AKI, whereas in late chronic stages had spatial proximity to fibroblasts. Further pseudotime analysis revealed two distinct lineages of macrophages in this transition: renal resident macrophages differentiated into the pro-repair subsets, whereas infiltrating monocyte-derived macrophages contributed to chronic inflammation and fibrosis. A novel macrophage subset, extracellular matrix remodeling-associated macrophages (EAMs) originating from monocytes, linked to renal fibrogenesis and communicated with fibroblasts via insulin-like growth factors (IGF) signalling. In sum, our study identified the spatiotemporal dynamics of macrophage heterogeneity with a unique subset of EAMs in AKI-to-CKD transition, which could be a potential therapeutic target for preventing CKD development.

Macrophage based drug delivery: Key challenges and strategies

As a natural immune cell and antigen presenting cell, macrophages have been studied and engineered to treat human diseases. Macrophages are well-suited for use as drug carriers because of their biological characteristics, such as excellent biocompatibility, long circulation, intrinsic inflammatory homing and phagocytosis. Meanwhile, macrophages' uniquely high plasticity and easy re-education polarization facilitates their use as part of efficacious therapeutics for the treatment of inflammatory diseases or tumors. Although recent studies have demonstrated promising advances in macrophage-based drug delivery, several challenges currently hinder further improvement of therapeutic effect and clinical application. This article focuses on the main challenges of utilizing macrophage-based drug delivery, from the selection of macrophage sources, drug loading, and maintenance of macrophage phenotypes, to drug migration and release at target sites. In addition, corresponding strategies and insights related to these challenges are described. Finally, we also provide perspective on shortcomings on the road to clinical translation and production.

Protective role for kidney TREM2high macrophages in obesity- and diabetes-induced kidney injury

Diabetic kidney disease (DKD), the most common cause of kidney failure, is a frequent complication of diabetes and obesity, and yet to date, treatments to halt its progression are lacking. We analyze kidney single-cell transcriptomic profiles from DKD patients and two DKD mouse models at multiple time points along disease progression-high-fat diet (HFD)-fed mice aged to 90-100 weeks and BTBR ob/ob mice (a genetic model)-and report an expanding population of macrophages with high expression of triggering receptor expressed on myeloid cells 2 (TREM2) in HFD-fed mice. TREM2high macrophages are enriched in obese and diabetic patients, in contrast to hypertensive patients or healthy controls in an independent validation cohort. Trem2 knockout mice on an HFD have worsening kidney filter damage and increased tubular epithelial cell injury, all signs of worsening DKD. Together, our studies suggest that strategies to enhance kidney TREM2high macrophages may provide therapeutic benefits for DKD.

Exosomes on the development and progression of renal fibrosis

Renal fibrosis is a prevalent pathological alteration that occurs throughout the progression of primary and secondary renal disorders towards end-stage renal disease. As a complex and irreversible pathophysiological phenomenon, it includes a sequence of intricate regulatory processes at the molecular and cellular levels. Exosomes are a distinct category of extracellular vesicles that play a crucial role in facilitating intercellular communication. Multiple pathways are regulated by exosomes produced by various cell types, including tubular epithelial cells and mesenchymal stem cells, in the context of renal fibrosis. Furthermore, research has shown that exosomes present in bodily fluids, including urine and blood, may be indicators of renal fibrosis. However, the regulatory mechanism of exosomes in renal fibrosis has not been fully elucidated. This article reviewed and analysed the various mechanisms by which exosomes regulate renal fibrosis, which may provide new ideas for further study of the pathophysiological process of renal fibrosis and targeted treatment of renal fibrosis with exosomes.

Potential immune-related therapeutic mechanisms of multiple traditional Chinese medicines on type 2 diabetic nephropathy based on bioinformatics, network pharmacology and molecular docking

BACKGROUND

The prevalence of type 2 diabetic nephropathy (T2DN) ranges from 20 % to 40 % among individuals with type 2 diabetes. Multiple immune pathways play a pivotal role in the pathogenesis of T2DN. This study aimed to investigate the immunomodulatory effects of active ingredients derived from 14 traditional Chinese medicines (TCMs) on T2DN.

METHODS

By removing batch effect on the GSE30528 and GSE96804 datasets, we employed a combination of weighted gene co-expression network analysis, least absolute shrinkage and selection operator analysis, protein-protein interaction network analysis, and the CIBERSORT algorithm to identify the active ingredients of TCMs as well as potential hub biomarkers associated with immune cells. Functional analysis was conducted using Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and gene set variation analysis (GSVA). Additionally, molecular docking was employed to evaluate interactions between active ingredients and potential immunotherapy targets.

RESULTS

A total of 638 differentially expressed genes (DEGs) were identified in this study, comprising 5 hub genes along with 4 potential biomarkers. Notably, CXCR1, CXCR2, and FOS exhibit significant associations with immune cells while displaying robust or favorable affinities towards the active ingredients kaempferol, quercetin, and luteolin. Furthermore, functional analysis unveiled intricate involvement of DEGs, hub genes and potential biomarkers in pathways closely linked to immunity and diabetes.

CONCLUSION

The potential hub biomarkers and immunotherapy targets associated with immune cells of T2DN comprise CXCR1, CXCR2, and FOS. Furthermore, kaempferol, quercetin, and luteolin demonstrate potential immunomodulatory effects in modulating T2DN through the regulation of CXCR1, CXCR2, and FOS expression.

Renal macrophages and NLRP3 inflammasomes in kidney diseases and therapeutics

Macrophages are exceptionally diversified cell types and perform unique features and functions when exposed to different stimuli within the specific microenvironment of various kidney diseases. In instances of kidney tissue necrosis or infection, specific patterns associated with damage or pathogens prompt the development of pro-inflammatory macrophages (M1). These M1 macrophages contribute to exacerbating tissue damage, inflammation, and eventual fibrosis. Conversely, anti-inflammatory macrophages (M2) arise in the same circumstances, contributing to kidney repair and regeneration processes. Impaired tissue repair causes fibrosis, and hence macrophages play a protective and pathogenic role. In response to harmful stimuli within the body, inflammasomes, complex assemblies of multiple proteins, assume a pivotal function in innate immunity. The initiation of inflammasomes triggers the activation of caspase 1, which in turn facilitates the maturation of cytokines, inflammation, and cell death. Macrophages in the kidneys possess the complete elements of the NLRP3 inflammasome, including NLRP3, ASC, and pro-caspase-1. When the NLRP3 inflammasomes are activated, it triggers the activation of caspase-1, resulting in the release of mature proinflammatory cytokines (IL)-1β and IL-18 and cleavage of Gasdermin D (GSDMD). This activation process therefore then induces pyroptosis, leading to renal inflammation, cell death, and renal dysfunction. The NLRP3-ASC-caspase-1-IL-1β-IL-18 pathway has been identified as a factor in the development of the pathophysiology of numerous kidney diseases. In this review, we explore current progress in understanding macrophage behavior concerning inflammation, injury, and fibrosis in kidneys. Emphasizing the pivotal role of activated macrophages in both the advancement and recovery phases of renal diseases, the article delves into potential strategies to modify macrophage functionality and it also discusses emerging approaches to selectively target NLRP3 inflammasomes and their signaling components within the kidney, aiming to facilitate the healing process in kidney diseases.

Exosomes From Human Umbilical Cord Stem Cells Suppress Macrophage-to-myofibroblast Transition, Alleviating Renal Fibrosis

Renal fibrosis, a progressive scarring of the kidney, lacks effective treatment. Human umbilical cord mesenchymal stem cell-derived exosomes (HucMSC-Exos) hold promise for treating kidney diseases due to their anti-inflammatory properties. This study investigates their potential to lessen renal fibrosis by targeting macrophage-to-myofibroblast transformation (MMT), a key driver of fibrosis. We employed a mouse model of unilateral ureteral obstruction (UUO) and cultured cells exposed to transforming growth factor-β (TGF-β) to mimic MMT. HucMSC-Exos were administered to UUO mice, and their effects on kidney function and fibrosis were assessed. Additionally, RNA sequencing and cellular analysis were performed to elucidate the mechanisms by which HucMSC-Exos inhibit MMT. HucMSC-Exos treatment significantly reduced kidney damage and fibrosis in UUO mice. They downregulated markers of fibrosis (Collagen I, vimentin, alpha-smooth muscle actin) and suppressed MMT (α-SMA + F4/80 + cells). Furthermore, ARNTL, a specific molecule, emerged as a potential target of HucMSC-Exos in hindering MMT and consequently preventing fibrosis. HucMSC-Exos effectively lessen renal fibrosis by suppressing MMT, suggesting a novel therapeutic strategy for managing kidney damage and fibrosis.

Targeting Macrophages: Therapeutic Approaches in Diabetic Kidney Disease

Diabetes is not solely a metabolic disorder but also involves inflammatory processes. The immune response it incites is a primary contributor to damage in target organs. Research indicates that during the initial phases of diabetic nephropathy, macrophages infiltrate the kidneys alongside lymphocytes, initiating a cascade of inflammatory reactions. The interplay between macrophages and other renal cells is pivotal in the advancement of kidney disease within a hyperglycemic milieu. While M1 macrophages react to the inflammatory stimuli induced by elevated glucose levels early in the disease progression, their subsequent transition to M2 macrophages, which possess anti-inflammatory and tissue repair properties, also contributes to fibrosis in the later stages of nephropathy by transforming into myofibroblasts. Comprehending the diverse functions of macrophages in diabetic kidney disease and regulating their activity could offer therapeutic benefits for managing this condition.

Guben Xiezhuo Decoction inhibits M1 polarization through the Raf1/p-Elk1 signaling axis to attenuate renal interstitial fibrosis

ETHNOPHARMACOLOGICAL RELEVANCE

Guben Xiezhuo Decoction (GBXZD) is an herbal compound used to treat chronic kidney disease (CKD) under the guidance of traditional Chinese medicine (TCM). Its main components are Astragalus membranaceus (Fisch.) Bunge, Codonopsis pilosula (Franch.) Nannf., Centella asiatica (L.) Urb., Salvia miltiorrhiza Bunge, Cuscuta chinensis Lam., and Rheum palmatum L.. Clinical studies have shown that it can relieve fatigue, nausea and other symptoms and improve kidney function in patients; however, its specific mechanism of action requires further study.

AIM OF THE STUDY

Renal interstitial fibrosis (RIF) is the ultimate characteristic manifestation of various CKD, that cannot be cured, and appropriate treatments to delay its progression require further exploration. GBXZD, widely used in clinical practice for RIF treatment, can effectively relieve the syndrome in patients with CKD. However, the specific mechanism of action of GBXZD in RIF is unknown and requires further study. This study aimed to explore the specific effects of GBXZD on RIF through the regulation of M1 macrophages.

MATERIALS AND METHODS

An in vivo RIF model was obtained through unilateral ureteral obstruction (UUO), and the Sprague-Dawley (SD) rats were randomly divided into sham operation, UUO, UUO + GBXZD-low dose (GBXZD-L) and UUO + GBXZD-high dose (GBXZD-H) groups. Pathological changes in rat kidney specimens were observed using hematoxylin and eosin (HE) and Masson staining. The expression of collagen I (COL I), fibronectin (FN), α-smooth muscle actin (α-SMA), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α) was detected using immunohistochemistry, and immunofluorescence was used to detect the expression of CD86 and inducible nitric-oxide synthase (iNOS) in kidney tissue. An in vitro experiment was performed using M1 polarization model in RAW264.7 macrophages induced by lipopolysaccharide (LPS). Cells were divided into control, LPS, LPS + GBXZD-low dose (GBXZD-L) and LPS + GBXZD-high dose (GBXZD-H) groups. The changes in expression of CD86, iNOS, IL-1β, IL-6, and TNF-α were measured using western blotting, flow cytometry, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). We analyzed the action pathway of GBXZD in regulating M1 polarization of macrophages using antibody microarray and verified the results using western blotting.

RESULTS

Histopathological results showed that the UUO group exhibited significant fibrotic injury compared to the sham group. After GBXZD treatment, the degree of kidney injury, RIF, and inflammatory factor expression were lower than those in the UUO group. Compared with LPS-treated cells, the expression of the M1 markers CD86, iNOS, and pathway proteins Raf1 and p-Elk1 was down-regulated in RAW 264.7 cells treated with LPS and GBXZD. The secretion of the inflammatory factors IL-1β, IL-6, and TNF-α in the LPS group was more than that in the control group. However, the levels of these factors were significantly reduced in the GBXZD-H group compared to those in the LPS group.

CONCLUSIONS

This study indicates that GBXZD ameliorates RIF and inhibits the inflammatory response and macrophage M1 polarization by a potential mechanism related to the downregulation of Raf1 and p-Elk1. GBXZD therefore has therapeutic potential value for patients with CKD.

LncRNA CASC2 Alleviates Renal Interstitial Inflammation and Fibrosis through MEF2C Downregulation-Induced Hinderance of M1 Macrophage Polarization

INTRODUCTION

Long noncoding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) alleviates the progression of diabetic nephropathy by inhibiting inflammation and fibrosis. This study investigated how CASC2 impacts renal interstitial fibrosis (RIF) through regulating M1 macrophage (M1) polarization.

METHOD

Nine-week-old mice underwent unilateral ureteral obstruction (UUO) establishment. Macrophages were induced toward M1 polarization using lipopolysaccharide (LPS) in vitro and cocultured with fibroblasts to examine how M1 polarization influences RIF. LnCeCell predicted that CASC2 interacted with myocyte enhancer factor 2 C (MEF2C), which was validated by dual-luciferase reporter assay. CASC2/MEF2C overexpression was achieved by lentivirus-expressing lncRNA CASC2 injection in vivo or CASC2 and MEF2C transfection in vitro. Renal injury was evaluated through biochemical analysis and hematoxylin-eosin/Masson staining. Macrophage infiltration and M1 polarization in the kidney and/or macrophages were detected by immunofluorescence, flow cytometry, and/or quantitative reverse transcription polymerase chain reaction (qRT-PCR). Expressions of CASC2, MEF2C, and markers related to inflammation/M1/fibrosis in the kidney/macrophages/fibroblasts were analyzed by qRT-PCR, fluorescence in situ hybridization, enzyme-linked immunosorbent assay, and/or Western blot.

RESULT

In the kidneys of mice, CASC2 was downregulated and macrophage infiltration was promoted time-dependently from days 3 to 14 post-UUO induction; CASC2 overexpression alleviated renal histological abnormalities, hindered macrophage infiltration and M1 polarization, downregulated renal function markers serum creatinine and blood urea nitrogen and inflammation/M1/fibrosis-related makers, and offset UUO-induced MEF2C upregulation. LncRNA CASC2 overexpression inhibited fibroblast fibrosis and M1 polarization in cocultured fibroblasts with LPS-activated macrophages. Also, CASC2 bound to MEF2C and inhibited its expression in LPS-activated macrophages. Furthermore, MEF2C reversed the inhibitory effects of lncRNA CASC2 overexpression.

CONCLUSION

CASC2 alleviates RIF by inhibiting M1 polarization through directly downregulating MEF2C expression. CASC2 might represent a promising value of future investigations on treatment for RIF.

Sustained activation of 12/15 lipoxygenase (12/15 LOX) contributes to impaired renal recovery post ischemic injury in male SHR compared to females

BACKGROUND

Acute kidney injury (AKI) due to ischemia-reperfusion (IR) is a serious and frequent complication in clinical settings, and mortality rates remain high. There are well established sex differences in renal IR, with males exhibiting greater injury following an ischemic insult compared to females. We recently reported that males have impaired renal recovery from ischemic injury vs. females. However, the mechanisms mediating sex differences in renal recovery from IR injury remain poorly understood. Elevated 12/15 lipoxygenase (LOX) activity has been reported to contribute to the progression of numerous kidney diseases. The goal of the current study was to test the hypothesis that enhanced activation of 12/15 LOX contributes to impaired recovery post-IR in males vs. females.

METHODS

13-week-old male and female spontaneously hypertensive rats (SHR) were randomized to sham or 30-minute warm bilateral IR surgery. Additional male and female SHR were randomized to treatment with vehicle or the specific 12/15 LOX inhibitor ML355 1 h prior to sham/IR surgery, and every other day following up to 7-days post-IR. Blood was collected from all rats 1-and 7-days post-IR. Kidneys were harvested 7-days post-IR and processed for biochemical, histological, and Western blot analysis. 12/15 LOX metabolites 12 and 15 HETE were measured in kidney samples by liquid chromatography-mass spectrometry (LC/MS).

RESULTS

Male SHR exhibited delayed recovery of renal function post-IR vs. male sham and female IR rats. Delayed recovery in males was associated with activation of renal 12/15 LOX, increased renal 12-HETE, enhanced endoplasmic reticulum (ER) stress, lipid peroxidation, renal cell death and inflammation compared to females 7-days post-IR. Treatment of male SHR with ML355 lowered levels of 12-HETE and resulted in reduced renal lipid peroxidation, ER stress, tubular cell death and inflammation 7-days post-IR with enhanced recovery of renal function compared to vehicle-treated IR male rats. ML355 treatment did not alter IR-induced increases in plasma creatinine in females, however, tubular injury and cell death were attenuated in ML355 treated females compared to vehicle-treated rats 7 days post-IR.

CONCLUSION

Our data demonstrate that sustained activation 12/15 LOX contributes to impaired renal recovery post ischemic injury in male and female SHR, although males are more susceptible on this mechanism than females.

Identification of the key immune-related genes and immune cell infiltration changes in renal interstitial fibrosis

Background

Chronic kidney disease (CKD) is the third-leading cause of premature mortality worldwide. It is characterized by rapid deterioration due to renal interstitial fibrosis (RIF) via excessive inflammatory infiltration. The aim of this study was to discover key immune-related genes (IRGs) to provide valuable insights and therapeutic targets for RIF in CKD.

Materials and methods

We screened differentially expressed genes (DEGs) between RIF samples from CKD patients and healthy controls from a public database. Least absolute shrinkage and selection operator regression analysis and receiver operating characteristic curve analysis were applied to identify significant key biomarkers. The single-sample Gene Set Enrichment Analysis (ssGSEA) algorithm was used to analyze the infiltration of immune cells between the RIF and control samples. The correlation between biomarkers and immune cell composition was assessed.

Results

A total of 928 DEGs between CKD and control samples from six microarray datasets were found, 17 overlapping immune-correlated DEGs were identified by integration with the ImmPort database, and six IRGs were finally identified in the model: apolipoprotein H (APOH), epidermal growth factor (EGF), lactotransferrin (LTF), lysozyme (LYZ), phospholipid transfer protein (PLTP), and secretory leukocyte peptidase inhibitor (SLPI). Two additional datasets and in vivo experiments indicated that the expression levels of APOH and EGF in the fibrosis group were significantly lower than those in the control group, while the expression levels of LTF, LYZ, PLTP, and SLPI were higher (all P < 0.05). These IRGs also showed a significant correlation with renal function impairment. Moreover, four upregulated IRGs were positively associated with various T cell populations, which were enriched in RIF tissues, whereas two downregulated IRGs had opposite results. Several signaling pathways, such as the "T cell receptor signaling pathway" and "positive regulation of NF-κB signaling pathway", were discovered to be associated not only with immune cell infiltration, but also with the expression levels of six IRGs.

Conclusion

In summary, six IRGs were identified as key biomarkers for RIF, and exhibited a strong correlation with various T cells and with the NF-κB signaling pathway. All these IRGs and their signaling pathways may evolve as valuable therapeutic targets for RIF in CKD.

Research progress and hotspots on macrophages in osteoarthritis: A bibliometric analysis from 2009 to 2022

BACKGROUND

Macrophages in the synovium, as immune cells, can be polarized into different phenotypes to play an anti-inflammatory role in the treatment of osteoarthritis. In this study, bibliometric methods were used to search the relevant literature to find valuable research directions for researchers and provide new targets for osteoarthritis prevention and early treatment.

METHODS

Studies about the application of macrophages in the treatment of osteoarthritis were searched through the Web of Science core database from 2009 to 2022. Microsoft Excel 2019, VOSviewer, CiteSpace, R software, and 2 online websites were used to analyze the research status and predict the future development of the trend in research on macrophages in osteoarthritis.

RESULTS

The number of publications identified with the search strategy was 1304. China and the United States ranked first in the number of publications. Shanghai Jiao Tong University ranked first in the world with 37 papers. Osteoarthritis and Cartilage was the journal with the most publications, and "exosomes," "stem cells," "macrophage polarization," "regeneration," and "innate immunity" may remain the research hotspots and frontiers in the future.

CONCLUSION

The findings from the global trend analysis indicate that research on macrophages in the treatment of osteoarthritis is gradually deepening, and the number of studies is increasing. Exosomes may become a research trend and hotspot in the future.

Relationship between Macrophages and Tissue Microenvironments in Diabetic Kidneys

Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease. Increasing evidence has suggested that inflammation is a key microenvironment involved in the development and progression of DN. Studies have confirmed that macrophage accumulation is closely related to the progression to human DN. Macrophage phenotype is highly regulated by the surrounding microenvironment in the diabetic kidneys. M1 and M2 macrophages represent distinct and sometimes coexisting functional phenotypes of the same population, with their roles implicated in pathological changes, such as in inflammation and fibrosis associated with the stage of DN. Recent findings from single-cell RNA sequencing of macrophages in DN further confirmed the heterogeneity and plasticity of the macrophages. In addition, intrinsic renal cells interact with macrophages directly or through changes in the tissue microenvironment. Macrophage depletion, modification of its polarization, and autophagy could be potential new therapies for DN.

Mechanisms Limiting Renal Tissue Protection and Repair in Glomerulonephritis

Glomerulonephritis are renal disorders resulting from different pathogenic mechanisms (i.e., autoimmunity, complement, inflammatory activation, etc.). Clarifying details of the pathogenic cascade is basic to limit the progression from starting inflammation to degenerative stages. The balance between tissue injury, activation of protective systems and renal tissue repair determines the final outcome. Induction of an oxidative stress is part of glomerular inflammation and activation of protective antioxidant systems has a crucial role in reducing tissue effects. The generation of highly reactive oxygen species can be evaluated in vivo by tracing the inner-layer content of phosphatidyl ethanolamine and phosphatidyl serine in cell membranes. Albumin is the major antioxidant in serum and the level of oxidized albumin is another indirect sign of oxidative stress. Studies performed in Gn, specifically in FSGS, showed a high degree of oxidation in most contexts. High levels of circulating anti-SOD2 antibodies, limiting the detoxyfing activity of SOD2, have been detected in autoimmune Gn(lupus nephritis and membranous nephropathy) in association with persistence of proteinuria and worsening of renal function. In renal transplant, high levels of circulating anti-Glutathione S-transferase antibodies have been correlated with chronic antibody rejection and progressive loss of renal function. Annexins, mainly ANXA1 and ANXA2, play a general anti-inflammatory effect by inhibiting neutrophil functions. Cytosolic ANXA1 is decreased in apoptotic neutrophils of patients with glomerular polyangitis in association with delayed apoptosis that is considered the mechanism for polyangitis. High circulating levels of anti-ANXA1 and anti-ANXA2 antibodies characterize lupus nephritis implying a reduced anti-inflammatory effect. High circulating levels of antibodies targeting Macrophages (anti-FMNL1) have been detected in Gn in association with proteinuria. They potentially modify the intra-glomerular presence of protective macrophages (M2a, M2c) thus acting on the composition of renal infiltrate and on tissue repair.

Androgen receptor blockade by flutamide down-regulates renal fibrosis, inflammation, and apoptosis pathways in male rats

AIM

this study aims to explore the effect of androgen receptor (AR) blockade by flutamide on some renal pathologic changes such as inflammation, apoptosis, and fibrosis in male rats.

MAIN METHODS

Firstly, we investigated the potential effect of AR blockade on renal inflammatory intermediates including IL-1β, IL-6, TNF-α, NF-Қβ proteins, and the renal gene expression of NF-Қβ. Besides inflammation, we also assessed the apoptosis pathways including the caspases 3 & 9, mTOR, pAKT proteins, and BAX gene expression. Besides inflammation and apoptosis pathways, we also investigated the effect of androgen blockade on renal fibrosis intermediates including vimentin, TGFβ-1, α-SMA, MMP-9, collagen type-III, collagen type-IV, and the renal expression of the col1A1 gene. Besides previous pathological pathways, we assessed the expression of chloride channel protein-5 (ClC-5), as an important regulator of many renal pathological changes. Finally, we assessed the impact of previous pathological changes on renal function at biochemical and pathological levels.

KEY FINDINGS

We found that AR blockade by flutamide was associated with the down-regulation of renal inflammation, apoptosis, and fibrosis markers. It was associated with expression down-regulation of IL-1β & IL-6, TNF-α, NF-Қβ, caspases 3 & 9, mTOR, MMP-9, collagens, TGFβ-1, and α-SMA. Away from down-regulation, we also found that AR blockade has upregulated ClC-5 and pAKT proteins.

SIGNIFICANCE

AR is a major player in androgens-induced nephrotoxicity. AR blockade downregulates renal fibrosis, inflammation, and apoptosis pathways. It may be helpful as a strategy for alleviation of renal side effects associated with some drugs. However; this needs further investigations.

Enhancer of zeste homolog 2 promotes renal fibrosis after acute kidney injury by inducing epithelial-mesenchymal transition and activation of M2 macrophage polarization

Long-term follow-up data indicates that 1/4 patients with acute kidney injury (AKI) will develop to chronic kidney disease (CKD). Our previous studies have demonstrated that enhancer of zeste homolog 2 (EZH2) played an important role in AKI and CKD. However, the role and mechanisms of EZH2 in AKI-to-CKD transition are still unclear. Here, we demonstrated EZH2 and H3K27me3 highly upregulated in kidney from patients with ANCA-associated glomerulonephritis, and expressed positively with fibrotic lesion and negatively with renal function. Conditional EZH2 deletion or pharmacological inhibition with 3-DZNeP significantly improved renal function and attenuated pathological lesion in ischemia/reperfusion (I/R) or folic acid (FA) mice models (two models of AKI-to-CKD transition). Mechanistically, we used CUT & Tag technology to verify that EZH2 binding to the PTEN promoter and regulating its transcription, thus regulating its downstream signaling pathways. Genetic or pharmacological depletion of EZH2 upregulated PTEN expression and suppressed the phosphorylation of EGFR and its downstream signaling ERK1/2 and STAT3, consequently alleviating the partial epithelial-mesenchymal transition (EMT), G2/M arrest, and the aberrant secretion of profibrogenic and proinflammatory factors in vivo and vitro experiments. In addition, EZH2 promoted the EMT program induced loss of renal tubular epithelial cell transporters (OAT1, ATPase, and AQP1), and blockade of EZH2 prevented it. We further co-cultured macrophages with the medium of human renal tubular epithelial cells treated with H₂O₂ and found macrophages transferred to M2 phenotype, and EZH2 could regulate M2 macrophage polarization through STAT6 and PI3K/AKT pathways. These results were further verified in two mice models. Thus, targeted inhibition of EZH2 might be a novel therapy for ameliorating renal fibrosis after acute kidney injury by counteracting partial EMT and blockade of M2 macrophage polarization.

The role of macrophages-mediated communications among cell compositions of tumor microenvironment in cancer progression

Recent studies have revealed that tumor-associated macrophages are the most abundant stromal cells in the tumor microenvironment and play an important role in tumor initiation and progression. Furthermore, the proportion of macrophages in the tumor microenvironment is associated with the prognosis of patients with cancer. Tumor-associated macrophages can polarize into anti-tumorigenic phenotype (M1) and pro-tumorigenic phenotype (M2) by the stimulation of T-helper 1 and T-helper 2 cells respectively, and then exert opposite effects on tumor progression. Besides, there also is wide communication between tumor-associated macrophages and other immune compositions, such as cytotoxic T cells, regulatory T cells, cancer-associated fibroblasts, neutrophils and so on. Furthermore, the crosstalk between tumor-associated macrophages and other immune cells greatly influences tumor development and treatment outcomes. Notably, many functional molecules and signaling pathways have been found to participate in the interactions between tumor-associated macrophages and other immune cells and can be targeted to regulate tumor progression. Therefore, regulating these interactions and CAR-M therapy are considered to be novel immunotherapeutic pathways for the treatment of malignant tumors. In this review, we summarized the interactions between tumor-associated macrophages and other immune compositions in the tumor microenvironment and the underlying molecular mechanisms and analyzed the possibility to block or eradicate cancer by regulating tumor-associated macrophage-related tumor immune microenvironment.

Therapeutic treatment with phosphodiesterase-4 inhibitors alleviates kidney injury and renal fibrosis by increasing MMP-9 in a doxorubicin-induced nephrotoxicity mouse model

Nephrotic syndrome (NS) is associated with kidney dysfunction and is an important cause of morbidity and mortality in industrialized countries. Here, we evaluated the effects of the phosphodiesterase-4 (PDE-4) inhibitors rolipram and roflumilast on a doxorubicin-induced NS model. Early-stage rolipram treatment preserved glomerular filtration barrier function, as indicated by reduced serum protein and albumin loss and the prevention of hypercholesterolemia. These effects were associated with reduced glomerular and tubular lesions and abrogated renal cell apoptosis. In addition, rolipram treatment reduced inflammation, which was characterized by a decrease in macrophage accumulation and reduced levels of CCL2 and TNF in the kidneys. Rolipram also reduced renal fibrosis, which was associated with decreased α-smooth muscle actin (α-SMA) area and increased metalloproteinase 9 (MMP9) activity in renal tissue. Late-stage rolipram or roflumilast treatment preserved glomerular filtration barrier function, as characterized by reduced serum albumin loss, decreased proteinuria, and the prevention of hypercholesterolemia. Importantly, only roflumilast treatment was associated with a reduction in glomerular and tubular lesions at this time point. In addition, both rolipram and roflumilast reduced renal tissue fibrosis and MMP9 activity in renal tissue.

Iron therapy mitigates chronic kidney disease progression by regulating intracellular iron status of kidney macrophages

Systemic iron metabolism is disrupted in chronic kidney disease (CKD). However, little is known about local kidney iron homeostasis and its role in kidney fibrosis. Kidney-specific effects of iron therapy in CKD also remain elusive. Here, we elucidate the role of macrophage iron status in kidney fibrosis and demonstrate that it is a potential therapeutic target. In CKD, kidney macrophages exhibited depletion of labile iron pool (LIP) and induction of transferrin receptor 1, indicating intracellular iron deficiency. Low LIP in kidney macrophages was associated with their defective antioxidant response and proinflammatory polarization. Repletion of LIP in kidney macrophages through knockout of ferritin heavy chain (Fth1) reduced oxidative stress and mitigated fibrosis. Similar to Fth1 knockout, iron dextran therapy, through replenishing macrophage LIP, reduced oxidative stress, decreased the production of proinflammatory cytokines, and alleviated kidney fibrosis. Interestingly, iron markedly decreased TGF-β expression and suppressed TGF-β-driven fibrotic response of macrophages. Iron dextran therapy and FtH suppression had an additive protective effect against fibrosis. Adoptive transfer of iron-loaded macrophages alleviated kidney fibrosis, validating the protective effect of iron-replete macrophages in CKD. Thus, targeting intracellular iron deficiency of kidney macrophages in CKD can serve as a therapeutic opportunity to mitigate disease progression.

Antioxidant, Anti-Apoptotic, and Anti-Inflammatory Effects of Farrerol in a Mouse Model of Obstructive Uropathy

Obstructive uropathy is a clinical condition that can lead to chronic kidney disease. However, treatments that can prevent the progression of renal injury and fibrosis are limited. Farrerol (FA) is a natural flavone with potent antioxidant and anti-inflammatory properties. Here, we investigated the effect of FA on renal injury and fibrosis in a mouse model of unilateral ureteral obstruction (UUO). Mice underwent a sham or UUO operation and received intraperitoneal injections of FA (20 mg/kg) daily for 8 consecutive days. Histochemistry, immunohistochemistry and immunofluorescence staining, TdT-mediated dUTP nick end labeling assay, Western blotting, gene expression analysis, and biochemical tests were performed. FA attenuated renal dysfunction (p < 0.05) and ameliorated renal tubular injury (p < 0.01) and interstitial fibrosis (p < 0.001) in UUO mice. FA alleviated 4-hydroxynonenal expression (p < 0.001) and malondialdehyde levels (p < 0.01) by regulating pro-oxidant and antioxidant enzymes. Apoptosis in the kidneys of UUO mice was inhibited by FA (p < 0.001), and this action was accompanied by decreased expression of cleaved caspase-3 (p < 0.01). Moreover, FA alleviated pro-inflammatory cytokine production (p < 0.001) and macrophage infiltration (p < 0.01) in the kidneys of UUO mice. These results suggest that FA ameliorates renal injury and fibrosis in the UUO model by inhibiting oxidative stress, apoptosis, and inflammation.

Effect of vitamin D analogues calcitriol and paricalcitol in a rat model of puromycin aminonucleoside-induced nephrotic syndrome

Background Renoprotective effects of vitamin D analogues have been shown in several experimental and clinical studies, the exact mechanism of the therapeutic effectiveness of these analogues in Nephrotic syndrome remains unclear, and these are relatively few studies on potential treatment roles for vitamin D analogues in nephrotic-range proteinuria. ?ndicate similar efficacy of the vitamin D analogues calcitriol and paricalcitol in time-limited amelioration of proteinuria in nephrotic syndrome, yet suggest the likelihood of mechanisms other than direct upregulation of nephrin and podocin in podocytes underlie the renoprotective effects of vitamin D analogues. Objective To investigate the effect of vitamin D (Vit D) analogues calcitriol and paricalcitol on urinary protein/creatinine ratio (UPCR) and renal podocin and nephrin expression in a rat model of puromycin aminonucleoside (PAN)-induced nephrotic syndrome (NS). Methods A total of 28 male Wistar Albino rats were separated into 4 groups (n=7 for each) including CON [control; intraperitoneal (IP) saline injection], PAN (NS + IP saline injection), PAN-C (NS + IP 0.4 µg/kg/day calcitriol injection), and PAN-P (NS + IP 240 ng/kg/day paricalcitol injection). Nephrotic syndrome was induced via intravenous (IV) administration of 10mg/100gr PAN. The UPCR as well as histopathological, immuno-histochemical, and real time PCR analyses of kidney tissue specimens were recorded and analyzed among the 4 groups. Results Median UPCR (Day 4) was significantly lower in both the PAN-C [1.45 (range 1.20-1.80)] and PAN-P [1.40 (range 1.10-1.80)] groups than in the PAN group [2.15 (range 2.00-2.40)] (P<0.01 for each). The PAN group had significantly higher mean UPCR than the CON group [1.75 (range 1.40-2.00); P<0.05].  No significant difference in UPCR was noted between groups on Day 7. Median podocin mRNA expression was significantly higher in the PAN-P group compared to the PAN group [22.55 (range 22.42-23.02) vs. 22.06 (range 21.81-22.06), respectively; (P<0.01)]. Conclusion Seven-day calcitriol and paricalcitol supplementation in a rat model of PAN-induced nephrotic syndrome had similar efficacy, in terms of temporary amelioration of proteinuria.

The single-cell landscape of kidney immune cells reveals transcriptional heterogeneity in early diabetic kidney disease

The pathogenesis of diabetic kidney disease (DKD) involves multifactorial processes that converge to initiate and advance the disease. Although DKD is not typically classified as an inflammatory glomerular disease, mounting evidence supports the involvement of kidney inflammation as a key contributor in DKD pathogenesis, particularly through macrophages. However, detailed identification and corresponding phenotypic changes of macrophages in DKD remain poorly understood. To capture the gene expression changes in specific macrophage cell subsets in early DKD, we performed single-cell transcriptomic analysis of CD45-enriched kidney immune cells from type 1 diabetic OVE26 mice at two time points during the disease development. We also undertook a focused analysis of mononuclear phagocytes (macrophages and dendritic cells). Our results show increased resident and infiltrating macrophage subsets in the kidneys of mice with diabetes over time, with heightened expression of pro-inflammatory or anti-inflammatory genes in a subset-specific manner. Further analysis of macrophage polarization states in each subset in the kidneys showed changes consistent with the continuum of activation and differentiation states, with gene expression tending to shift toward undifferentiated phenotypes but with increased M1-like inflammatory phenotypes over time. By deconvolution analysis of RNAseq samples and by immunostaining of biopsies from patients with DKD, we further confirmed a differential expression of select genes in specific macrophage subsets essentially recapitulating the studies in mice. Thus, our study provides a comprehensive analysis of macrophage transcriptomic profiles in early DKD that underscores the dynamic macrophage phenotypes in disease progression.

High Macrophage Densities in Native Kidney Biopsies Correlate With Renal Dysfunction and Promote ESRD

Introduction

Macrophages and monocytes are main players in innate immunity. The relevance of mononuclear phagocyte infiltrates on clinical outcomes remains to be determined in native kidney diseases.

Methods

Our cross-sectional study included 324 patients with diagnostic renal biopsies comprising 17 disease entities and normal renal tissues for comparison. All samples were stained for CD68⁺ macrophages. Selected groups were further subtyped for CD14⁺ monocytes and CD163⁺ alternatively activated macrophages. Using precise pixel-based digital measurements, we quantified cell densities as positively stained areas in renal cortex and medulla as well as whole renal tissue. Laboratory and clinical data of all cases at the time of biopsy and additional follow-up data in 158 cases were accessible.

Results

Biopsies with renal disease consistently revealed higher CD68⁺-macrophage densities and CD163⁺-macrophage densities in cortex and medulla compared to controls. High macrophage densities correlated with impaired renal function at biopsy and at follow-up in all diseases and in diseases analyzed separately. High cortical CD68⁺-macrophage densities preceded shorter renal survival, defined as requirement of permanent dialysis. CD14⁺ monocyte densities showed no difference compared to controls and did not correlate with renal function.

Conclusion

Precise quantification of macrophage densities in renal biopsies may contribute to risk stratification to identify patients with high risk for end-stage renal disease (ESRD) and might be a promising therapeutic target in renal disease.

M2c Macrophages Protect Mice from Adriamycin-Induced Nephropathy by Upregulating CD62L in Tregs

Regulatory T cells (Tregs) and M2c macrophages have been shown to exert potentially synergistic therapeutic effects in animals with adriamycin-induced nephropathy (AN), a model chronic proteinuric renal disease. M2c macrophages may protect against renal injury by promoting an increase in the number of Tregs in the renal draining lymph nodes of AN mice, but how they do so is unclear. In this study, we used an AN mouse model to analyze how M2c macrophages induce the migration of Tregs. Using flow cytometry, we found that M2c macrophages promoted the migration of Tregs from the peripheral blood to the spleen, thymus, kidney, and renal draining lymph nodes. At the same time, M2c macrophages significantly upregulated chemokine receptors and adhesion molecule in Tregs, including CCR4, CCR5, CCR7, CXCR5, and CD62L. Treating AN mice with monoclonal anti-CD62L antibody inhibited the migration of M2c macrophages and Tregs to the spleen, thymus, kidney, and renal draining lymph nodes. Taken together, our results suggest that M2c macrophages upregulate CD62L in Tregs and thereby promote their migration to inflammatory sites, where they exert renoprotective effects. These insights may aid the development of treatments against chronic kidney disease.

Annexin A2 and Kidney Diseases

Annexin A2 is a Ca²⁺- and phospholipid-binding protein which is widely expressed in various types of cells and tissues. As a multifunctional molecule, annexin A2 is found to be involved in diverse cell functions and processes, such as cell exocytosis, endocytosis, migration and proliferation. As a receptor of plasminogen and tissue plasminogen activator, annexin A2 promotes plasmin generation and regulates the homeostasis of blood coagulation, fibrinolysis and matrix degradation. As an antigen expressed on cell membranes, annexin A2 initiates local inflammation and damage through binding to auto-antibodies. Annexin A2 also mediates multiple signaling pathways induced by various growth factors and oxidative stress. Aberrant expression of annexin A2 has been found in numerous kidney diseases. Annexin A2 has been shown to act as a co-receptor of integrin CD11b mediating NF-kB-dependent kidney inflammation, which is further amplified through annexin A2/NF-kB-triggered macrophage M2 to M1 phenotypic change. It also modulates podocyte cytoskeleton rearrangement through Cdc42 and Rac1/2/3 Rho pathway causing proteinuria. Thus, annexin A2 is implicated in the pathogenesis and progression of various kidney diseases. In this review, we focus on the current understanding of the role of annexin A2 in kidney diseases.

Biomimetic Micelles to Accurately Regulate the Inflammatory Microenvironment for Glomerulonephritis Treatment

Glomerulonephritis is a key factor in leading to end-stage renal disease. Mesangial cell proliferation and macrophage infiltration are two prominent features linked in a vicious circle mechanism for glomerulonephritis progression. Herein, a novel biomimetic pH-sensitive nanomicelle (MM/HA-DXM) was constructed to synergize hyaluronic acid (HA)-activated macrophage phenotypic remodeling and dexamethasone (DXM)-mediated mesangial cell killing for precise treatment of glomerulonephritis. Owing to the camouflaged coating with endogenous macrophage membrane (MM), MM/HA-DXM could escape from RES phagocytosis and then be recruited to inflammatory glomerulus by active homing effect. Afterwards, HA-DXM nanomicelles ruptured in response to the weakly acidic glomerulonephritis microenvironment, to locally release HA and DXM. On the one hand, DXM can inhibit the abnormal proliferation of mesangial cells. On the other hand, HA transformed pro-inflammatory M1 macrophages into anti-inflammatory M2 phenotype to improve the glomerular inflammatory microenvironment. In doxorubicin-induced glomerulonephritis models, results revealed that MM/HA-DXM could specifically "homing" to inflammatory renal tissue with 4.33-fold improvement in targeting performance. In addition, in vivo pharmacodynamic results proved that after treatment with MM/HA-DXM, the proteinuria level decreased to 2.33 times, as compared with that of control group, demonstrating a superior therapeutic effect on glomerulonephritis via this collaborative two-pronged anti-inflammatory therapy strategy.

Hemangiosarcoma cells induce M2 polarization and PD-L1 expression in macrophages

Hemangiosarcoma (HSA) is a malignant tumor derived from endothelial cells. Tumor-associated macrophages are one of the major components of tumor microenvironment and crucial for cancer development. The presence and function of macrophages in HSA have not been studied because there is no syngeneic model for HSA. In this study, we evaluated two mouse HSA cell lines and one immortalized mouse endothelial cell line for their usefulness as syngeneic models for canine HSA. Our results showed that the ISOS-1 cell line developed tumors with similar morphology to canine HSA. ISOS-1 cells highly expressed KDM2B and had similar KDM2B target expression patterns with canine HSA. Moreover, we determined that in both ISOS-1 and canine HSA tumors, macrophages were present as a major constituent of the tumor microenvironment. These macrophages were positive for CD204, an M2 macrophage marker, and express PD-L1, an immune checkpoint molecule. Canine HSA with macrophages expressing PD-L1 had a smaller number of T-cells in tumor tissues than tumors with PD-L1 negative macrophages. ISOS-1-conditioned medium could induce M2 polarization and PD-L1 expression in RAW264.7 mouse macrophage cell line and mouse peritoneal macrophages. These results show that ISOS-1 can be used as a syngenic model for canine HSA and suggest that macrophages play an important role in immune evasion in HSA. Using the syngeneic mouse model for canine HSA, we can further study the role of immune cells in the pathology of HSA.

The Myeloid-Kidney Interface in Health and Disease

Kidney homeostasis is highly dependent upon the correct functioning of myeloid cells. These cells form a distributed surveillance network throughout the kidney, where they play an integral role in the response to organ threat. Dysregulation of resident proinflammatory and profibrotic macrophages leads to kidney structural damage and scarring after kidney injury. Fibrosis throughout the kidney parenchyma contributes to the progressive functional decline observed in CKD, independent of the etiology. Circulating myeloid cells bearing intrinsic defects also affect the kidney substructures, such as neutrophils activated by autoantibodies that cause GN in ANCA-associated vasculitis. The kidney can also be affected by disorders of myelopoiesis, including myeloid leukemias (acute and chronic myeloid leukemias) and myelodysplastic syndromes. Clonal hematopoiesis of indeterminate potential is a common, newly recognized premalignant clinical entity characterized by clonal expansion of hyperinflammatory myeloid lineage cells that may have significant kidney sequelae. A number of existing therapies in CKD target myeloid cells and inflammation, including glucocorticoid receptor agonists and mineralocorticoid receptor antagonists. The therapeutic indications for these and other myeloid cell-targeted treatments is poised to expand as our understanding of the myeloid-kidney interface evolves.

Molecular Mechanisms of Kidney Injury and Repair

Chronic kidney disease (CKD) will become the fifth global cause of death by 2040, thus emphasizing the need to better understand the molecular mechanisms of damage and regeneration in the kidney. CKD predisposes to acute kidney injury (AKI) which, in turn, promotes CKD progression. This implies that CKD or the AKI-to-CKD transition are associated with dysfunctional kidney repair mechanisms. Current therapeutic options slow CKD progression but fail to treat or accelerate recovery from AKI and are unable to promote kidney regeneration. Unraveling the cellular and molecular mechanisms involved in kidney injury and repair, including the failure of this process, may provide novel biomarkers and therapeutic tools. We now review the contribution of different molecular and cellular events to the AKI-to-CKD transition, focusing on the role of macrophages in kidney injury, the different forms of regulated cell death and necroinflammation, cellular senescence and the senescence-associated secretory phenotype (SAPS), polyploidization, and podocyte injury and activation of parietal epithelial cells. Next, we discuss key contributors to repair of kidney injury and opportunities for their therapeutic manipulation, with a focus on resident renal progenitor cells, stem cells and their reparative secretome, certain macrophage subphenotypes within the M2 phenotype and senescent cell clearance.

Urinary Soluble CD163 Levels Predict IgA Nephropathy Remission Status

Noninvasive biomarkers of disease activity are needed to predict disease remission status in patients with IgA nephropathy (IgAN). Soluble CD163 (sCD163), shed by monocytes and macrophages, is a potential biomarker in diseases associated with excessive macrophage activation. We investigated the association of urinary sCD163 (u-sCD163) with histopathological activity and clinical manifestations in 349 patients with biopsy-diagnosed IgAN. U-sCD163 was measured via enzyme-linked immunosorbent assay. In patients with IgAN, higher u-sCD163 levels were associated with histological lesions of greater severity, as well as more proteinuria and poorer renal function. Additionally, u-sCD163 was correlated with infiltration of tubulointerstitial CD163⁺ macrophages. High u-sCD163 levels (>3.57 ng/mg Cr) were associated with a 2.66-fold greater risk for IgAN remission failure in adjusted analyses. Adding u-sCD163 levels to the model containing clinical data at biopsy and MEST-C score significantly improved the risk prediction of IgAN remission status (AUC 0.788). Together, our results suggest that u-sCD163 may be a useful noninvasive biomarker to evaluate disease severity and remission status of IgAN.

Rho GTPases in kidney physiology and diseases

Rho family GTPases are molecular switches best known for their pivotal role in dynamic regulation of the actin cytoskeleton, but also of cellular morphology, motility, adhesion and proliferation. The prototypic members of this family (RhoA, Rac1 and Cdc42) also contribute to the normal kidney function and play important roles in the structure and function of various kidney cells including tubular epithelial cells, mesangial cells and podocytes. The kidney's vital filtration function depends on the structural integrity of the glomerulus, the proximal portion of the nephron. Within the glomerulus, the architecturally actin-based cytoskeleton podocyte forms the final cellular barrier to filtration. The glomerulus appears as a highly dynamic signalling hub that is capable of integrating intracellular cues from its individual structural components. Dynamic regulation of the podocyte cytoskeleton is required for efficient barrier function of the kidney. As master regulators of actin cytoskeletal dynamics, Rho GTPases are therefore of critical importance for sustained kidney barrier function. Dysregulated activities of the Rho GTPases and of their effectors are implicated in the pathogenesis of both hereditary and idiopathic forms of kidney diseases. Diabetic nephropathy is a progressive kidney disease that is caused by injury to kidney glomeruli. High glucose activates RhoA/Rho-kinase in mesangial cells, leading to excessive extracellular matrix production (glomerulosclerosis). This RhoA/Rho-kinase pathway also seems involved in the post-transplant hypertension frequently observed during treatment with calcineurin inhibitors, whereas Rac1 activation was observed in post-transplant ischaemic acute kidney injury.

Activated Platelets, the Booster of Chronic Kidney Disease and Cardiovascular Complications

<b><i>Background:</i></b> Chronic kidney disease (CKD) has become a global public health problem nowadays. As cardiovascular diseases (CVDs) are the primary cause of death in advanced CKD patients, much attention has been paid to resolving their cardiovascular complications. However, managing CKD and cardiovascular complications is still a big challenge for nephrologists, as satisfactory treatments are still lacking. Platelets, the second most abundant cells in the blood, are the major participants of hemostasis, thrombosis, and wound healing. In recent years, platelets have been reported in various physiological and pathological processes, including CKD and CKD-related CVDs.

FcER1: A Novel Molecule Implicated in the Progression of Human Diabetic Kidney Disease

Diabetic kidney disease (DKD) is a key microvascular complication of diabetes, with few therapies for targeting renal disease pathogenesis and progression. We performed transcriptional and protein studies on 103 unique blood and kidney tissue samples from patients with and without diabetes to understand the pathophysiology of DKD injury and its progression. The study was based on the use of 3 unique patient cohorts: peripheral blood mononuclear cell (PBMC) transcriptional studies were conducted on 30 patients with DKD with advancing kidney injury; Gene Expression Omnibus (GEO) data was downloaded, containing transcriptional measures from 51 microdissected glomerulous from patients with DKD. Additionally, 12 independent kidney tissue sections from patients with or without DKD were used for validation of target genes in diabetic kidney injury by kidney tissue immunohistochemistry and immunofluorescence. PBMC DKD transcriptional analysis, identified 853 genes (p < 0.05) with increasing expression with progression of albuminuria and kidney injury in patients with diabetes. GEO data was downloaded, normalized, and analyzed for significantly changed genes. Of the 325 significantly up regulated genes in DKD glomerulous (p < 0.05), 28 overlapped in PBMC and diabetic kidney, with perturbed FcER1 signaling as a significantly enriched canonical pathway. FcER1 was validated to be significantly increased in advanced DKD, where it was also seen to be specifically co-expressed in the kidney biopsy with tissue mast cells. In conclusion, we demonstrate how leveraging public and private human transcriptional datasets can discover and validate innate immunity and inflammation as key mechanistic pathways in DKD progression, and uncover FcER1 as a putative new DKD target for rational drug design.

The NLRP3 inhibitor dapansutrile attenuates folic acid induced nephrotoxicity via inhibiting inflammasome/caspase-1/IL axis and regulating autophagy/proliferation

AIMS

Chemical renal toxicity is common and has limited therapeutic interventions. The NLRP3 inhibitor dapansutrile (DAPA) undergoes clinical phase II trials and it shows promising beneficial effects in various inflammatory diseases. The current study aims at evaluating the effect of DAPA on folic acid (FA) induced acute kidney injury (AKI) and its possible transition to chronic injury.

MATERIALS AND METHODS

Two treatment protocols were studied depending on DAPA injection timing. A prophylactic protocol involving the injection of DAPA (0.2 mg/kg) daily for seven days before FA challenge and a therapeutic protocol where DAPA was injected after FA. Each protocol included four groups of rats: control group, DAPA group, FA group and DAPA+FA group. Serum creatinine, urea and uric acid were measured. Also, kidney injury, necrosis and fibrosis percentage in addition to infiltration of CD68 positive cells were evaluated. Activation markers of inflammasome and the expression of Ki-67 and LC-3 were measured.

KEY FINDINGS

Results showed an improvement in renal tissue integrity and a significant decrease in kidney function biomarkers, caspase-1, IL-1β and IL-18 by DAPA injection (p < 0.05). In addition, DAPA decreased the proliferation marker Ki-67 and the autophagic marker LC-3 (p < 0.01).

SIGNIFICANCE

DAPA potentially alleviates FA induced nephrotoxicity through targeting inflammasome/caspase-1/IL axis. Moreover, it shows a regulatory effect on renal regeneration and autophagy.

Properties of macrophages and lymphocytes appearing in rat renal fibrosis followed by repeated injection of cisplatin

Properties of macrophages and lymphocytes appearing in renal fibrosis remains to be investigated. F344 rats were injected once a week with cisplatin (2 mg/kg body weight) for 8 weeks and examined at post-final injection weeks 1, 3, 6, 9, and 12. Rats developed progressive renal fibrosis at weeks 1 to 6 as fibrosis-progress phase, and subsequent amelioration at weeks 9 and 12. CD68+ M1-macrophages and major histocompatibility complex (MHC) class II+ macrophages remarkably increased persistently, whereas CD163+ M2-macrophages slightly increased. MHC class II+/CD68+ and MHC class II+/CD163+ macrophages were present, indicating that MHC class II+ macrophages might have both functions of M1- and M2-macrophages. In the fibrosis-progress phase, interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ for M1-factors, and transforming growth factor (TGF)-β1 and IL-10 for M2-factors tended to increase; tissue injury by M1 and fibrosis by M2 might have occurred simultaneously. Lots of CD4+ and CD8+ T cells appeared in close relation with MHC class II+ macrophages, and mainly CD4+ T cells formed aggregations. In the lymphocyte aggregates collected by laser microdissection, expression of IL-17A (for Th17 cells) and forkhead box P3 (FoxP3) (for Treg) significantly increased at weeks 1 and 6, respectively; presumably, Th17 cells might be involved in tissue injury, whereas Treg might be related to fibrosis amelioration. These results suggested that macrophages and T cells may contribute interrelatedly to renal fibrosis.

The Role of Macrophages in Kidney Fibrosis

The phenotypic heterogeneity and functional diversity of macrophages confer on them complexed roles in the development and progression of kidney diseases. After kidney injury, bone marrow-derived monocytes are rapidly recruited to the glomerulus and tubulointerstitium. They are activated and differentiated on site into pro-inflammatory M1 macrophages, which initiate Th1-type adaptive immune responses and damage normal tissues. In contrast, anti-inflammatory M2 macrophages induce Th2-type immune responses, secrete large amounts of TGF-β and anti-inflammatory cytokines, transform into αSMA+ myofibroblasts in injured kidney, inhibit immune responses, and promote wound healing and tissue fibrosis. Previous studies on the role of macrophages in kidney fibrosis were mainly focused on inflammation-associated injury and injury repair. Apart from macrophage-secreted profibrotic cytokines, such as TGF-β, evidence for a direct contribution of macrophages to kidney fibrosis is lacking. However, under inflammatory conditions, Wnt ligands are derived mainly from macrophages and Wnt signaling is central in the network of multiple profibrotic pathways. Largely underinvestigated are the direct contribution of macrophages to profibrotic signaling pathways, macrophage phenotypic heterogeneity and functional diversity in relation to kidney fibrosis, and on their cross-talk with other cells in profibrotic signaling networks that cause fibrosis. Here we aim to provide an overview on the roles of macrophage phenotypic and functional diversity in their contribution to pro-fibrotic signaling pathways, and on the therapeutic potential of targeting macrophages for the treatment of kidney fibrosis.

Endothelin receptors in renal interstitial cells do not contribute to the development of fibrosis during experimental kidney disease

Renal interstitial fibrosis is characterized by the development of myofibroblasts, originating from resident renal and immigrating cells. Myofibroblast formation and extracellular matrix production during kidney damage are triggered by various factors. Among these, endothelins have been discussed as potential modulators of renal fibrosis. Utilizing mouse models of adenine nephropathy (AN) and unilateral ureter occlusion (UUO), this study aimed to investigate the contribution of endothelin signaling in stromal mesenchymal resident renal interstitial cells. We found in controls that adenine feeding and UUO caused marked upregulations of endothelin-1 (ET-1) gene expression in endothelial and in tubular cells and a strong upregulation of ET_A-receptor (ET_A-R) gene expression in interstitial and mesangial cells, while the gene expression of ET_B-receptor (ET_B-R) did not change. Conditional deletion of ET_A-R and ET_B-R gene expression in the FoxD1 stromal cell compartment which includes interstitial cells significantly reduced renal ET_A-R gene expression and moderately lowered renal ET_B-R gene expression. ET receptor (ET-R) deletion exerted no apparent effects on kidney development nor on kidney function. Adenine feeding and UUO led to similar increases in profibrotic and proinflammatory gene expression in control as well as in ET_A^flflET_B^flfl FoxD1^Cre+ mice (ET-Ko). In summary, our findings suggest that adenine feeding and UUO activate endothelin signaling in interstitial cells which is due to upregulated ET_A-R expression and enhanced renal ET-1 production Our data also suggest that the activation of endothelin signaling in interstitial cells has less impact for the development of experimentally induced fibrosis.

Role of Macrophages and Related Cytokines in Kidney Disease

Inflammation is a key characteristic of kidney disease, but this immune response is two-faced. In the acute phase of kidney injury, there is an activation of the immune cells to fight against the insult, contributing to kidney repair and regeneration. However, in chronic kidney diseases (CKD), immune cells that infiltrate the kidney play a deleterious role, actively participating in disease progression, and contributing to nephron loss and fibrosis. Importantly, CKD is a chronic inflammatory disease. In early CKD stages, patients present sub-clinical inflammation, activation of immune circulating cells and therefore, anti-inflammatory strategies have been proposed as a common therapeutic target for renal diseases. Recent studies have highlighted the plasticity of immune cells and the complexity of their functions. Among immune cells, monocytes/macrophages play an important role in all steps of kidney injury. However, the phenotype characterization between human and mice immune cells showed different markers; therefore the extrapolation of experimental studies in mice could not reflect human renal diseases. Here we will review the current information about the characteristics of different macrophage phenotypes, mainly focused on macrophage-related cytokines, with special attention to the chemokine CCL18, and its murine functional homolog CCL8, and the macrophage marker CD163, and their role in kidney pathology.

Regulation of Monocytes/Macrophages by the Renin-Angiotensin System in Diabetic Nephropathy: State of the Art and Results of a Pilot Study

Diabetic nephropathy (DN) is characterized by albuminuria, loss of renal function, renal fibrosis and infiltration of macrophages originating from peripheral monocytes inside kidneys. DN is also associated with intrarenal overactivation of the renin-angiotensin system (RAS), an enzymatic cascade which is expressed and controlled at the cell and/or tissue levels. All members of the RAS are present in the kidneys and most of them are also expressed in monocytes/macrophages. This review focuses on the control of monocyte recruitment and the modulation of macrophage polarization by the RAS in the context of DN. The local RAS favors the adhesion of monocytes on renal endothelial cells and increases the production of monocyte chemotactic protein-1 and of osteopontin in tubular cells, driving monocytes into the kidneys. There, proinflammatory cytokines and the RAS promote the differentiation of macrophages into the M1 proinflammatory phenotype, largely contributing to renal lesions of DN. Finally, resolution of the inflammatory process is associated with a phenotype switch of macrophages into the M2 anti-inflammatory subset, which protects against DN. The pharmacologic interruption of the RAS reduces albuminuria, improves the trajectory of the renal function, decreases macrophage infiltration in the kidneys and promotes the switch of the macrophage phenotype from M1 to M2.

Immunophenotypical Characterization of M1/M2 Macrophages and Lymphocytes in Cisplatin-Induced Rat Progressive Renal Fibrosis

Renal fibrosis is regarded as the common final pathway leading to chronic kidney diseases; macrophages and myofibroblasts play important roles in the development of fibrosis. F344 rats were injected once with cisplatin (CDDP; 6 mg/kg BW) for renal lesions. Here, immunophenotypical characteristics of macrophages and lymphocytes in CDDP-induced rat renal lesions were investigated histopathologically; the CDDP-induced renal lesions consisted of tissue damage at the early-stage, worsen the damage and commencement of interstitial fibrosis at the mid-stage, and progressive fibrosis at the late stage; the KIM-1 expression and α-SMA+ myofibroblast area reflected renal tubular damage/abnormal regeneration and renal interstitial fibrosis, respectively. CD68+ M1 macrophages began to increase at the mid-stage, with increased mRNA expressions of M1-related cytokines (INF-γ, TNF-α and IL-6), and then slightly decreased at the late-stage. CD163+ M2 macrophages showed a gradually increased number at the mid- and late-stages, accompanied by increased TGF-β1 mRNA expression (a fibrogenic factor). Double immunofluorescence using fibrotic samples at the late-stage revealed that 62.0-78.0% of CD68+ M1 macrophages co-expressed CD163, indicating that M1/M2 macrophages may contribute to progressive renal fibrosis in cooperation; further, MHC class II-expressing macrophages had a tendency towards M1 polarization, whereas CD204-expressing macrophages towards M2 polarization. In addition, CD4+ and CD8+ T cells were increased at the late-stage. Collectively, progressive renal interstitial fibrosis may be developed by complicated mechanisms that arose via interaction of M1/M2 macrophages (inflammatory for M1 and anti-inflammatory for M2) and T cells reacting to CD4 (for helper) and CD8 (for cytotoxicity). This study would provide some information on the pathogenesis of renal fibrosis based on inflammatory cells.

M2 Macrophage Subpopulations in Glomeruli Are Associated With the Deposition of IgG Subclasses and Complements in Primary Membranous Nephropathy

Objectives: The role of M2 macrophages in the pathogenesis and progression of primary membranous nephropathy (PMN) remains unknown. In this study, we aimed to investigate the relationship between M2 subsets and clinicopathological features of patients with PMN. Methods: A total of 55 patients with PMN confirmed by biopsy were recruited. The clinical and pathological data were recorded, respectively. Immunohistochemistry was used to detect the markers of M2 macrophages, including total macrophages (CD68+), M2a (CD206+), M2b (CD86+) and M2c (CD163+). Results: The numbers of glomerular macrophages, M2a, M2b, and M2c macrophages were 1.83 (1.00, 2.67), 0.65 (0.15, 1.15), 0.67 (0.33, 1.50), and 0.80 (0.05, 2.30) per glomerulus, respectively. Higher number of glomerular macrophages was found in stage II compared with stage III (2.08 vs. 1.16, P = 0.008). These macrophages also were negatively correlated with serum albumin level (r = -0.331, P = 0.014), while positively associated with complement 3 (C3) deposition (r = 0.300, P = 0.026) and the severity of glomerulosclerosis (r = 0.276, P = 0.041). Moreover, glomerular M2a macrophages were significantly correlated with the deposition of C3 (r = 0.300, P = 0.026), immunoglobulin G1 (IgG1) (r = 0.339, P = 0.011), immunoglobulin G2 (IgG2) (r = 0.270, P = 0.046) and immunoglobulin G3 (IgG3) (r = 0.330, P = 0.014) in glomerular basement membrane (GBM). In addition, M2b macrophages were positively associated with IgG1 (r = 0.295, P = 0.029) and IgG2 (r = 0.393, P = 0.003), while M2c macrophages were negatively correlated with complement 4d (C4d) (r = -0.347, P = 0.009) in GBM. Conclusions: Our results showed that M2 macrophage subpopulations in glomeruli are associated with the deposition of IgG subclasses and complements in renal tissue of PMN, which indicate that M2 macrophages may be involved in the pathogenesis and progression of PMN. Moreover, M2a and M2c macrophages might show different tendencies in the pathogenesis of PMN.

Single-Cell Transcriptomics Reveal Immune Mechanisms of the Onset and Progression of IgA Nephropathy

IgA nephropathy (IgAN) is the leading cause of kidney failure due to an incomplete understanding of its pathogenesis. We perform single-cell RNA sequencing (RNA-seq) on kidneys and CD14⁺ peripheral blood mononuclear cells (PBMCs) collected from IgAN and normal samples. In IgAN, upregulation of JCHAIN in mesangial cells provides insight into the trigger mechanism for the dimerization and deposition of IgA1 in situ. The pathological mesangium also demonstrates a prominent inflammatory signature and increased cell-cell communication with other renal parenchymal cells and immune cells, suggesting disease progress from the mesangium to the entire kidney. Specific gene expression of kidney-resident macrophages and CD8⁺ T cells further indicates abnormal regulation associated with proliferation and inflammation. A transitional cell type among intercalated cells with fibrosis signatures is identified, suggesting an adverse outcome of interstitial fibrosis. Altogether, we systematically analyze the molecular events in the onset and progression of IgAN, providing a promising landscape for disease treatment.

Acetaminophen-Induced Rat Hepatotoxicity Based on M1/M2-Macrophage Polarization, in Possible Relation to Damage-Associated Molecular Patterns and Autophagy

Overdose of acetaminophen (APAP), an antipyretic drug, is an important cause of liver injury. However, the mechanism in the rat model remains undetermined. We analyzed APAP-induced hepatotoxicity using rats based on M1/M2-macrophage functions in relation to damage-associated molecular patterns (DAMPs) and autophagy. Liver samples from six-week-old rats injected with APAP (1000 mg/kg BW, ip, once) after 15 h fasting were collected at hour 10, and on days 1, 2, 3, and 5. Liver lesions consisting of coagulation necrosis and inflammation were seen in the affected centrilobular area on days 1 and 2, and then, recovered with reparative fibrosis by day 5. Liver exudative enzymes increased transiently on day 1. CD68⁺ M1-macrophages increased significantly on days 1 and 2 with increased mRNAs of M1-related cytokines such as IFN-g and TNF-α, whereas CD163⁺ M2-macrophages appeared later on days 2 and 3. Macrophages reacting to MHC class II and Iba1 showed M1-type polarization, and CD204⁺ macrophages tended to be polarized toward M2-type. At hour 10, interestingly, HMGB1 (representative DAMPs) and its related signals, TLR-9 and MyD88, as well as LC3B⁺ autophagosomes began to increase. Collectively, the pathogenesis of rat APAP hepatotoxicity, which is the first, detailed report for a rat model, might be influenced by macrophage functions of M1 type for tissue injury/inflammation and M2-type for anti-inflammatory/fibrosis; particularly, M1-type may function in relation to DAMPs and autophagy. Understanding the interplayed mechanisms would provide new insight into hepato-pathogenesis and contribute to the possible development of therapeutic strategies.

Inhibition of Renal Stellate Cell Activation Reduces Renal Fibrosis

Interstitial fibrosis is a common feature of chronic kidney disease, and platelet-derived growth factor receptor-β (PDGFR-β)-positive mesenchymal cells are reportedly the major source of scar-producing myofibroblasts. We had previously demonstrated that albumin and its derivative R-III (a retinol-binding protein-albumin domain III fusion protein) inhibited the transdifferentiation/activation of hepatic stellate cells (HSCs) to myofibroblasts and that R-III administration reduced liver fibrosis. In this study, we isolated cells (referred to as renal stellate cells, RSCs) from rat kidney tissues using the HSC isolation protocol and compared their morphological and biochemical characteristics with those of HSCs. RSCs shared many characteristics with HSCs, such as storage of vitamin A-containing lipid droplets and expression of HSC markers as well as pericyte markers. RSCs underwent spontaneous transdifferentiation into myofibroblasts in in vitro culture, which was inhibited by albumin expression or R-III treatment. We also evaluated the therapeutic effects of R-III in unilateral ureteral obstruction (UUO)-induced renal fibrosis in mice. Injected R-III localized predominantly in cytoglobin/stellate cell activation-associated protein (Cygb/STAP)-positive cells in the kidney and reduced renal fibrosis. These findings suggest that RSCs can be recognized as the renal counterparts of HSCs and that RSCs represent an attractive therapeutic target for anti-fibrotic therapy.

Total Flavones of Abelmoschus manihot Remodels Gut Microbiota and Inhibits Microinflammation in Chronic Renal Failure Progression by Targeting Autophagy-Mediated Macrophage Polarization

Background

Recently, progression of chronic renal failure (CRF) has been closely associated with gut microbiota dysbiosis and intestinal metabolite-derived microinflammation. In China, total flavones of Abelmoschus manihot (TFA), a component of Abelmoschus manihot, has been widely used to delay CRF progression in clinics for the past two decades. However, the overall therapeutic mechanisms remain obscure. In this study, we designed experiments to investigate the renoprotective effects of TFA in CRF progression and its underlying mechanisms involved in gut microbiota and microinflammation, compared with febuxostat (FEB), a potent non-purine selective inhibitor of xanthine oxidase.

Methods

In vivo, the CRF rat models were induced by uninephrectomy, potassium oxonate, and proinflammatory diet, and received either TFA suspension, FEB, or vehicle after modeling for 28 days. In vitro, the RAW 264.7 cells were exposed to lipopolysaccharide (LPS) with or without TFA or FEB. Changes in parameters related to renal injury, gut microbiota dysbiosis, gut-derived metabolites, and microinflammation were analyzed in vivo. Changes in macrophage polarization and autophagy and its related signaling were analyzed both in vivo and in vitro.

Results

For the modified CRF model rats, the administration of TFA and FEB improved renal injury, including renal dysfunction and renal tubulointerstitial lesions; remodeled gut microbiota dysbiosis, including decreased Bacteroidales and Lactobacillales and increased Erysipelotrichales; regulated gut-derived metabolites, including d-amino acid oxidase, serine racemase, d-serine, and l-serine; inhibited microinflammation, including interleukin 1β (IL1β), tumor necrosis factor-α, and nuclear factor-κB; and modulated macrophage polarization, including markers of M1/M2 macrophages. More importantly, TFA and FEB reversed the expression of beclin1 (BECN1) and phosphorylation of p62 protein and light chain 3 (LC3) conversion in the kidneys by activating the adenosine monophosphate-activated protein kinase-sirtuin 1 (AMPK-SIRT1) signaling. Further, TFA and FEB have similar effects on macrophage polarization and autophagy and its related signaling in vitro.

Conclusion

In this study, we demonstrated that TFA, similar to FEB, exerts its renoprotective effects partially by therapeutically remodeling gut microbiota dysbiosis and inhibiting intestinal metabolite-derived microinflammation. This is achieved by adjusting autophagy-mediated macrophage polarization through AMPK-SIRT1 signaling. These findings provide more accurate information on the role of TFA in delaying CRF progression.

Mechanistic Insights of Soluble Uric Acid-related Kidney Disease

Hyperuricemia, defined as the presence of elevated serum uric acid (sUA), could lead to urate deposit in joints, tendons, kidney and other tissues. Hyperuricemia as an independent risk factor was common in patients during the causation and progression of kidney disease. Uric acid is a soluble final product of endogenous and dietary purine metabolism, which is freely filtered in kidney glomeruli where approximately 90% of filtered uric acid is reabsorbed. Considerable studies have demonstrated that soluble uric acid was involved in the pathophysiology of renal arteriolopathy, tubule injury, tubulointerstitial fibrosis, as well as glomerular hypertrophy and glomerulosclerosis. In the review, we summarized the mechanistic insights of soluble uric acid related renal diseases.

IL-17A as a Potential Therapeutic Target for Patients on Peritoneal Dialysis

Chronic kidney disease (CKD) is a health problem reaching epidemic proportions. There is no cure for CKD, and patients may progress to end-stage renal disease (ESRD). Peritoneal dialysis (PD) is a current replacement therapy option for ESRD patients until renal transplantation can be achieved. One important problem in long-term PD patients is peritoneal membrane failure. The mechanisms involved in peritoneal damage include activation of the inflammatory and immune responses, associated with submesothelial immune infiltrates, angiogenesis, loss of the mesothelial layer due to cell death and mesothelial to mesenchymal transition, and collagen accumulation in the submesothelial compact zone. These processes lead to fibrosis and loss of peritoneal membrane function. Peritoneal inflammation and membrane failure are strongly associated with additional problems in PD patients, mainly with a very high risk of cardiovascular disease. Among the inflammatory mediators involved in peritoneal damage, cytokine IL-17A has recently been proposed as a potential therapeutic target for chronic inflammatory diseases, including CKD. Although IL-17A is the hallmark cytokine of Th17 immune cells, many other cells can also produce or secrete IL-17A. In the peritoneum of PD patients, IL-17A-secreting cells comprise Th17 cells, γδ T cells, mast cells, and neutrophils. Experimental studies demonstrated that IL-17A blockade ameliorated peritoneal damage caused by exposure to PD fluids. This article provides a comprehensive review of recent advances on the role of IL-17A in peritoneal membrane injury during PD and other PD-associated complications.

Dexamethasone prodrug nanomedicine (ZSJ-0228) treatment significantly reduces lupus nephritis in mice without measurable side effects - A 5-month study

Lupus nephritis (LN) is a major cause of morbidity and mortality among systemic lupus erythematosus patients. Glucocorticoids (GCs) are uniformly used in clinical LN management. Their notorious toxicities, however, have hampered the long-term clinical application. To circumvent GC side effects while maintaining their potent therapeutic efficacy, we have developed a macromolecular prodrug nanomedicine based on dexamethasone (ZSJ-0228). The focus of this study was to investigate its long-term efficacy and, most importantly, safety in the lupus-prone NZB/W F1 mouse. Monthly ZSJ-0228 treatment for five months significantly reduced the incidence of nephritis in NZB/W F1 mice with an improved survival rate. In contrast to treatment with dose equivalent daily free dexamethasone, long-term monthly ZSJ-0228 did not result in any measurable GC-associated side effects. With its outstanding efficacy and exceptional safety, it is anticipated that ZSJ-0228 may be a novel therapy for long-term clinical management of LN.