Novel Immunomodulatory Cytokine Regulates Inflammation, Diabetes, and Obesity to Protect From Diabetic Nephropathy

Evolution and global research trends of immunity in diabetic nephropathy: a bibliometric and visual analysis from 2004 to 2023

BACKGROUND

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease, with an increasing prevalence worldwide, but its pathomechanisms remain incompletely understood. Accumulating evidence suggests that immunity plays an important role in the development of DN. Many papers have been published in the field over the last 20 years, but there has been no bibliometric review of the research hotspots and trends in the field. This study aimed to assess the current research status and future trends of the link between immune and DN using bibliometric analysis.

METHODS

Publications on the association between immunity and DN from 2004 to 2023 were retrieved from the Web of Science Core Collection database and screened according to inclusion criteria. VOSviewer and CiteSpace software were employed to visualize research trends and hotspots in the field. Data including author, institution, country, journal, reference, and keyword were analyzed.

RESULTS

Ultimately 1246 publications meeting the criteria were included in the bibliometric analysis, involving 838 articles (84.96%) and 408 reviews (15.04%). The literature covered 81 countries and regions, 1751 institutions, and 6584 authors. The top 2 countries in terms of the number of publications were China (435) and the United States (318), and they collaborated most frequently. The United States had the highest number of citations for published papers (18,161), far exceeding the other countries. England had 38 publications but had the highest average number of citations (92.32). The University of California system was the most prolific institution (25 papers, 1062 citations, 42.48 citations per paper). Frontiers in Immunology was the most prolific journal in the field (30 papers). The most cited journal was Kidney International (863 citations). The analysis of keywords and references showed that inflammation, ferroptosis, and lipid metabolism may be future research hotspots in this field.

CONCLUSIONS

The number of publications related to immunity and DN has increased annually over the past 20 years, with a significant increase in the last 3 years especially. Our results identified research hotspots and trends in the field. These findings provide valuable perspectives for future research, enhancing our understanding of the immune-related mechanisms of DN and exploring potential therapeutic strategies.

Uncovering the Role of Anoikis-Related Genes in Modulating Immune Infiltration and Pathogenesis of Diabetic Kidney Disease

Background

Diabetic kidney disease (DKD) is an intricate complication of diabetes with limited treatment options. Anoikis, a programmed cell death activated by loss of cell anchorage to the extracellular matrix, participated in various physiological and pathological processes. Our study aimed to elucidate the role of anoikis-related genes in DKD pathogenesis.

Methods

Differentially expressed genes (DEGs) associated with anoikis in DKD were identified. Weighted gene co-expression network analysis (WGCNA) was conducted to identify DKD-correlated modules and assess their functional implications. A diagnostic model for DKD was developed using LASSO regression and Gene set variation analysis (GSVA) was performed for enrichment analysis. Experimental validation was employed to validate the significance of selected genes in the progression of DKD.

Results

We identified 10 anoikis-related DEGs involved in key signaling pathways impacting DKD progression. WGCNA highlighted the yellow module's significant enrichment in immune response and regulatory pathways. Correlation analysis further revealed the association between immune infiltration and anoikis-related DEGs. Our LASSO regression-based diagnostic model demonstrated a well-predictive efficacy with seven identified genes. GSVA indicated that gene function in the high-risk group was primarily associated with immune regulation. Further experimental validation using diabetic mouse models and data analysis in the single-cell dataset confirmed the significance of PYCARD and SFN in DKD progression. High glucose stimulation in RAW264.7 and TCMK-1 cells showed significantly increased expression levels of both Pycard and Sfn. Co-expression analysis demonstrated distinct functions of PYCARD and SFN, with KEGG pathway analysis showing significant enrichment in immune regulation and cell proliferation pathway.

Conclusion

In conclusion, our study provides valuable insights into the molecular mechanisms involved in DKD pathogenesis, specifically highlighting the role of anoikis-related genes in modulating immune infiltration. These findings suggest that targeting these genes may hold promise for future diagnostic and therapeutic approaches in DKD management.

Group2 innate lymphoid cells ameliorate renal fibrosis and dysfunction associated with adenine-induced CKD

Renal fibrosis is a common pathway of chronic kidney disease (CKD) progression involving primary kidney injury and kidney diseases. Group 2 innate lymphoid cells (ILC2s) mediate type 2 immune responses irrespective of antigen presentation and play a reno-protective role in kidney injury and disease. In the present study, we observed a decrease in kidney-resident ILC2s in CKD and found that enrichment of ILC2s in the kidney ameliorates renal fibrosis. In CKD kidney, ILC2s preferentially produced IL-13 over IL-5 in response to IL-33 stimulation, regardless of ST2L expression. Moreover, GATA3 expression was decreased in ILC2s, and T-bet+ ILC1s and RORγt+ ILC3s were increased in CKD kidney. Adoptive transfer of kidney ILC2s into adenine-induced CKD model mouse improved renal function and fibrosis. Renal fibroblasts cultured with IL33-activated kidney ILC2s suppressed myofibroblast trans-differentiation through Acta2 and Fn-1 regulation. These results suggest that kidney ILC2s prevent CKD progression via improvement of renal fibrosis. Our findings also suggest that ILC2s may contribute to the development of new therapeutic agents and strategies for tissue fibroses.

Inulin Reduces Kidney Damage in Type 2 Diabetic Mice by Decreasing Inflammation and Serum Metabolomics

This study is aimed at assessing the impact of soluble dietary fiber inulin on the treatment of diabetes-related chronic inflammation and kidney injury in mice with type 2 diabetes (T2DM). The T2DM model was created by feeding the Institute of Cancer Research (ICR) mice a high-fat diet and intraperitoneally injecting them with streptozotocin (50 mg/kg for 5 consecutive days). The thirty-six ICR mice were divided into three dietary groups: the normal control (NC) group, the T2DM (DM) group, and the DM + inulin diet (INU) group. The INU group mice were given inulin at the dose of 500 mg/kg gavage daily until the end of the 12th week. After 12 weeks, the administration of inulin resulted in decreased serum levels of fasting blood glucose (FBG), low-density lipoprotein cholesterol (LDL-C), blood urea nitrogen (BUN), and creatinine (CRE). The administration of inulin not only ameliorated renal injury but also resulted in a reduction in the mRNA expressions of inflammatory factors in the spleen and serum oxidative stress levels, when compared to the DM group. Additionally, inulin treatment in mice with a T2DM model led to a significant increase in the concentrations of three primary short-chain fatty acids (SCFAs) (acetic acid, propionic acid, and butyric acid), while the concentration of advanced glycation end products (AGEs), a prominent inflammatory factor in diabetes, exhibited a significant decrease. The results of untargeted metabolomics indicate that inulin has the potential to alleviate inflammatory response and kidney damage in diabetic mice. This beneficial effect is attributed to its impact on various metabolic pathways, including glycerophospholipid metabolism, taurine and hypotaurine metabolism, arginine biosynthesis, and tryptophan metabolism. Consequently, oral inulin emerges as a promising treatment option for diabetes and kidney injury.

Blood Eosinophil Count and Its Determinants in a Chinese Population-Based Cohort

INTRODUCTION

Blood eosinophil count has been shown markedly variable across different populations. However, its distribution in Chinese general population remains unclear. We aimed to investigate blood eosinophil count and its determinants in a Chinese general population.

METHODS

In this population-based study, general citizens of Sichuan province in China were extracted from the China Pulmonary Health study. Data on demographics, personal and family history, living condition, lifestyle, spirometry, and complete blood count test were obtained and analyzed. A stepwise multivariate binary logistic regression analysis was performed to identify determinants of high blood eosinophils (>75th percentile).

RESULTS

A total of 3,310 participants were included, with a mean age (standard deviation) of 47.0 (15.6) years. In total population, the median blood eosinophil count was 110.0 (interquartile range [IQR]: 67.2-192.9) cells/μL, lower than that in smokers (133.4 cells/μL, IQR: 79.3-228.4) and patients with asthma (140.7 cells/μL, IQR: 79.6-218.2) or post-bronchodilator airflow limitation (141.5 cells/μL, IQR: 82.6-230.1), with a right-skewed distribution. Multivariate analyses revealed that oldness (aged ≥60 years) (odds ratio [OR]: 1.66, 95% confidence interval [CI]: 1.11-2.48), smoking ≥20 pack-years (OR: 1.90, 95% CI: 1.20-3.00), raising a dog/cat (OR: 1.72, 95% CI: 1.17-2.52), and occupational exposure to dust, allergen, and harmful gas (OR: 1.58, 95% CI: 1.15-2.15) were significantly associated with high blood eosinophils.

CONCLUSION

This study identifies a median blood eosinophil count of 110.0 cells/μL and determinants of high blood eosinophils in a Chinese general population, including oldness (aged ≥60 years), smoking ≥20 pack-years, raising a dog/cat, and occupational exposure to dust, allergen, and harmful gas.

Revisiting regulatory T cells as modulators of innate immune response and inflammatory diseases

Regulatory T cells (Treg) are known to be critical for the maintenance of immune homeostasis by suppressing the activation of auto- or allo-reactive effector T cells through a diverse repertoire of molecular mechanisms. Accordingly, therapeutic strategies aimed at enhancing Treg numbers or potency in the setting of autoimmunity and allogeneic transplants have been energetically pursued and are beginning to yield some encouraging outcomes in early phase clinical trials. Less well recognized from a translational perspective, however, has been the mounting body of evidence that Treg directly modulate most aspects of innate immune response under a range of different acute and chronic disease conditions. Recognizing this aspect of Treg immune modulatory function provides a bridge for the application of Treg-based therapies to common medical conditions in which organ and tissue damage is mediated primarily by inflammation involving myeloid cells (mononuclear phagocytes, granulocytes) and innate lymphocytes (NK cells, NKT cells, γδ T cells and ILCs). In this review, we comprehensively summarize pre-clinical and human research that has revealed diverse modulatory effects of Treg and specific Treg subpopulations on the range of innate immune cell types. In each case, we emphasize the key mechanistic insights and the evidence that Treg interactions with innate immune effectors can have significant impacts on disease severity or treatment. Finally, we discuss the opportunities and challenges that exist for the application of Treg-based therapeutic interventions to three globally impactful, inflammatory conditions: type 2 diabetes and its end-organ complications, ischemia reperfusion injury and atherosclerosis.

Microbiota and Glucidic Metabolism: A Link with Multiple Aspects and Perspectives

The global prevalence of overweight and obesity has dramatically increased in the last few decades, with a significant socioeconomic burden. In this narrative review, we include clinical studies aiming to provide the necessary knowledge on the role of the gut microbiota in the development of diabetic pathology and glucose-metabolism-related disorders. In particular, the role of a certain microbial composition of the fermentative type seems to emerge without a specific link to the development in certain subjects of obesity and the chronic inflammation of the adipose tissues, which underlies the pathological development of all the diseases related to glucose metabolism and metabolic syndrome. The gut microbiota plays an important role in glucose tolerance. Conclusion. New knowledge and new information is presented on the development of individualized therapies for patients affected by all the conditions related to reduced glucose tolerance and insulin resistance.

Forkhead box P3 gene polymorphisms predispose to type 2 diabetes and diabetic nephropathy in the Han Chinese populations: a genetic-association and gender-based evaluation study

BACKGROUND

Functional mutations or polymorphisms affecting forkhead box P3 (FOXP3) can lead to their abnormal FOXP3 gene expression and/or defective Treg cells generation, thus resulting in autoimmune disease and inflammatory disorders. FOXP3 also plays a key role in Type 2 diabetes mellitus (T2DM) and its complications, because the disease usually involves chronic low-grade inflammatory disorders and is associated with long-term immune system imbalance. This study aimed to investigate the association between FOXP3 polymorphisms and the susceptibility to T2DM and type 2 diabetes nephropathy (T2DN) within the Han Chinese populations.

METHODS

Polymorphisms in rs3761548C/A and rs2294021C/T were examined in 400 patients (which include an equal number of T2DM and T2DN groups) and 200 healthy controls using PCR-HRM and sequence analysis.

RESULTS

The genotype and allelic frequencies of the two single nucleotide polymorphisms (SNPs) were significantly different in T2DM and the progression of diabetes developing to T2DN. The further gender-based evaluation showed that in female subjects, rs3761548C/A was associated with an approximately 3-fold higher threat for T2DM and 4.5-fold for T2DN, while there was no noticeable association with rs2294021C/T; in males, the promoter polymorphism showed an increased predisposition of 5.4-fold and 3.4-fold predisposition to T2DM and T2DN, respectively, while rs2294021 polymorphism could impart a nearly 2-fold risk of developing T2DN. An additional analysis of combined genotypes (rs3761548 C/A-rs2294021C/T) revealed that CC-CC and CC-CT can be considered protective combinations in the predisposition of males with diabetes towards T2DN, while AA-CC and AA-TT have the opposite effect.

CONCLUSIONS

This study demonstrated the possible involvement of individual and combined genetic associations of rs3761548C/A and rs2294021C/T polymorphisms with the susceptibility to diabetes and diabetic nephropathy in the Han Chinese population, as well as gender bias.

T cells and their products in diabetic kidney disease

Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease and has gradually become a public health problem worldwide. DKD is increasingly recognized as a comprehensive inflammatory disease that is largely regulated by T cells. Given the pivotal role of T cells and T cells-producing cytokines in DKD, we summarized recent advances concerning T cells in the progression of type 2 diabetic nephropathy and provided a novel perspective of immune-related factors in diabetes. Specific emphasis is placed on the classification of T cells, process of T cell recruitment, function of T cells in the development of diabetic kidney damage, and potential treatments and therapeutic strategies involving T cells.

IL-33 attenuates renal fibrosis via group2 innate lymphoid cells

Renal fibrosis is a common pathway in the progression of various kidney diseases and injuries. Unilateral ureteral obstruction (UUO) induces renal fibrosis, and immune responses profoundly affect its pathogenesis. Group2 innate lymphoid cells (ILC2s) are strongly activated by interleukin (IL) -33, which is a member of IL-1 family and recognize as alarmin. ILC2s quickly produce large amounts of type 2 cytokines including IL-5 and IL-13, which are involved in inflammation, tissue homeostasis, and wound healing. However, the relationship between renal fibrosis and ILC2s has been unclear. In the present study, we investigated the roles of the ILC2/L-33 axis in renal fibrosis using a UUO model. We found that kidney ILC2s decreased in UUO-affected kidneys compared with their counterpart kidneys despite IL-33 upregulation. There was no effect of reactive oxygen species or TGF-β from reduced ILC2 caused by UUO. Pretreatment with IL-33 before UUO induced ILC2s and Tregs in kidneys and alleviated renal fibrosis. Furthermore, this protective effect was maintained even when CD4⁺T cells was depleted. These findings demonstrated that ILC2s play a predominant role in the suppressive function of renal fibrosis mediated by pretreatment with IL-33. In contrast, post-treatment with IL-33 after UUO increased ILC2s in kidneys but had no therapeutic effect on renal fibrosis. Our findings suggest that ILC2s have potential roles in the prevention of renal fibrosis and can serve as a therapeutic and diagnostic target.

Screening and Identification of Hub Genes in the Development of Early Diabetic Kidney Disease Based on Weighted Gene Co-Expression Network Analysis

Objective

The study aimed to screen key genes in early diabetic kidney disease (DKD) and predict their biological functions and signaling pathways using bioinformatics analysis of gene chips interrelated to early DKD in the Gene Expression Omnibus database.

Methods

Gene chip data for early DKD was obtained from the Gene Expression Omnibus expression profile database. We analyzed differentially expressed genes (DEGs) between patients with early DKD and healthy controls using the R language. For the screened DEGs, we predicted the biological functions and relevant signaling pathways by enrichment analysis of Gene Ontology (GO) biological functions and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathways. Using the STRING database and Cytoscape software, we constructed a protein interaction network to screen hub pathogenic genes. Finally, we performed immunohistochemistry on kidney specimens from the Beijing Hospital to verify the above findings.

Results

A total of 267 differential genes were obtained using GSE142025, namely, 176 upregulated and 91 downregulated genes. GO functional annotation enrichment analysis indicated that the DEGs were mainly involved in immune inflammatory response and cytokine effects. KEGG pathway analysis indicated that C-C receptor interactions and the IL-17 signaling pathway are essential for early DKD. We identified FOS, EGR1, ATF3, and JUN as hub sites of protein interactions using a protein-protein interaction network and module analysis. We performed immunohistochemistry (IHC) on five samples of early DKD and three normal samples from the Beijing Hospital to label the proteins. This demonstrated that FOS, EGR1, ATF3, and JUN in the early DKD group were significantly downregulated.

Conclusion

The four hub genes FOS, EGR1, ATF3, and JUN were strongly associated with the infiltration of monocytes, M2 macrophages, and T regulatory cells in early DKD samples. We revealed that the expression of immune response or inflammatory genes was suppressed in early DKD. Meanwhile, the FOS group of low-expression genes showed that the activated biological functions included mRNA methylation, insulin receptor binding, and protein kinase A binding. These genes and pathways may serve as potential targets for treating early DKD.

Berberine protects diabetic nephropathy by suppressing epithelial-to-mesenchymal transition involving the inactivation of the NLRP3 inflammasome

Accumulating evidence has implicated that berberine (BBR) has a beneficial effect on diabetic kidney disease (DKD), but its mechanism is not clear. The aim of this study was to assess whether berberine could alleviate tubulointerstitial fibrosis and attenuate epithelial-to-mesenchymal transition (EMT) and its possible molecular mechanism. High-fat diet (HFD) followed by injection of STZ was used to induce diabetic rats in vivo. After the onset of diabetes, rats were treated with either BBR or saline for 12 weeks. In vitro, the human renal proximal tubular epithelial cell line (HK-2) was exposed to high glucose, with or without BBR. The influence of berberine on renal tubulointerstitial histological changes, markers of epithelial-to-mesenchymal transition (EMT) and (NOD-like receptor pyrin domain-containing protein 3) NLRP3 inflammasome expression were examined. Results showed that in vivo, BBR could significantly ameliorate microalbumin and renal pathologic changes in diabetic rats. Immunofluorescence showed that BBR could inhibit EMT. Furthermore, BBR could down-regulate the level of the NLRP3 inflammasome in diabetic rats. Consistently, in vitro, BBR suppressed high glucose-induced EMT and activation of NLRP3 inflammasome in HK-2. Our study demonstrated that BBR could inhibit high glucose-induced EMT and renal interstitial fibrosis by suppressing the NLRP3 inflammasome. BBR might be used as a novel drug to ameliorate tubulointerstitial fibrosis in DKD.

Mechanism of Cordyceps sinensis and its Extracts in the Treatment of Diabetic Kidney Disease: A Review

Diabetic kidney disease (DKD) is the major reason of chronic kidney disease (CKD)-caused end-stage renal failure (ESRF), and leads to high mortality worldwide. At present, the treatment of DKD is mainly focused on controlling the hyperglycemia, proteinuria, and hypertension, but is insufficient on the effective delay of DKD progression. Cordyceps sinensis is a kind of wild-used precious Chinese herb. Its extracts have effects of nephroprotection, hepatoprotection, neuroprotection, and protection against ischemia/reperfusion-induced injury, as well as anti-inflammatory and anti-oxidant activities. According to the theory of traditional Chinese medicine, Cordyceps sinensis can tonify the lung and the kidney. Several Chinese patent medicines produced from Cordyceps sinensis are often used to treat DKD and achieved considerable efficacy. This review summarized the clinical usage of Cordyceps sinensis, as well as its mainly biological activities including anti-hyperglycemic, anti-inflammatory, immunomodulatory, anti-oxidant, anti-fibrotic activities and regulation of apoptosis.

A Deep Insight Into Regulatory T Cell Metabolism in Renal Disease: Facts and Perspectives

Kidney disease encompasses a complex set of diseases that can aggravate or start systemic pathophysiological processes through their complex metabolic mechanisms and effects on body homoeostasis. The prevalence of kidney disease has increased dramatically over the last two decades. CD4⁺CD25⁺ regulatory T (Treg) cells that express the transcription factor forkhead box protein 3 (Foxp3) are critical for maintaining immune homeostasis and preventing autoimmune disease and tissue damage caused by excessive or unnecessary immune activation, including autoimmune kidney diseases. Recent studies have highlighted the critical role of metabolic reprogramming in controlling the plasticity, stability, and function of Treg cells. They are also likely to play a vital role in limiting kidney transplant rejection and potentially promoting transplant tolerance. Metabolic pathways, such as mitochondrial function, glycolysis, lipid synthesis, glutaminolysis, and mammalian target of rapamycin (mTOR) activation, are involved in the development of renal diseases by modulating the function and proliferation of Treg cells. Targeting metabolic pathways to alter Treg cells can offer a promising method for renal disease therapy. In this review, we provide a new perspective on the role of Treg cell metabolism in renal diseases by presenting the renal microenvironment、relevant metabolites of Treg cell metabolism, and the role of Treg cell metabolism in various kidney diseases.

Interleukin-33 Exacerbates IgA Glomerulonephritis in Transgenic Mice Overexpressing B Cell Activating Factor

BACKGROUND

The cytokine IL-33 is an activator of innate lymphoid cells 2 (ILC2s) in innate immunity and allergic inflammation. B cell activating factor (BAFF) plays a central role in B cell proliferation and differentiation, and high levels of this protein cause excess antibody production, including IgA. BAFF-transgenic mice overexpress BAFF and spontaneously develop glomerulonephritis that resembles human IgA nephropathy.

METHODS

We administered IL-33 or PBS to wild-type and BAFF-transgenic mice. After treating Rag1-deficient mice with IL-33, with or without anti-CD90.2 to preferentially deplete ILC2s, we isolated splenocytes, which were adoptively transferred into BAFF-transgenic mice.

RESULTS

BAFF-transgenic mice treated with IL-33 developed more severe kidney dysfunction and proteinuria, glomerular sclerosis, tubulointerstitial damage, and glomerular deposition of IgA and C3. Compared with wild-type mice, BAFF-transgenic mice exhibited increases of CD19⁺ B cells in spleen and kidney and ILC2s in kidney and intestine, which were further increased by administration of IL-33. Administering IL-33 to wild-type mice had no effect on kidney function or histology, nor did it alter the number of ILC2s in spleen, kidney, or intestine. To understand the role of ILC2s, splenocytes were transferred from IL-33-treated Rag1-deficient mice into BAFF-transgenic mice. Glomerulonephritis and IgA deposition were exacerbated by transfer of IL-33-stimulated Rag1-deficient splenocytes, but not by ILC2 (anti-CD90.2)-depleted splenocytes. Wild-type mice infused with IL-33-treated Rag1-deficient splenocytes showed no change in kidney function or ILC2 numbers or distribution.

CONCLUSIONS

IL-33-expanded ILC2s exacerbated IgA glomerulonephritis in a mouse model. These findings indicate that IL-33 and ILC2s warrant evaluation as possible mediators of human IgA nephropathy.

The relationship between B-cell lymphoma 2, interleukin-1β, interleukin-17, and interleukin-33 and the development of diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is among the main complications of diabetes mellitus and has been a major factor of renal failure. This study was designed to address the association between beta-cell lymphoma-2 (Bcl-2), interleukin (IL)-1β, IL-17, and IL-33 and the development of DN.

METHODS

In this study, 20 healthy volunteers and 100 patients were enrolled. According to their biochemical markers, the patients were categorized into five groups: diabetic, chronic renal disease, diabetic chronic renal disease, end-stage renal disease, and diabetic end-stage renal disease.

RESULTS

Our results showed a noticeable elevation in IL-1β and IL-17 levels and a reduction in IL-33 and Bcl-2 levels in all investigated groups compared with those in the healthy group. Positive correlations were found between IL-1β and fasting blood sugar and between creatinine levels and IL-17, HbA1c%, and sodium levels. However, negative correlations were found between IL-33 and urea and sodium concentrations and between Bcl-2 and HbA1c% and creatinine levels.

CONCLUSIONS

The present data revealed a marked relationship between Bcl-2, IL-1β, IL-17, and IL-33 levels and the onset and progression of DN. Understanding the molecular pathways of these processes could be translated into the development of therapeutic strategies.

Identification of CCL19 as a Novel Immune-Related Biomarker in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the major microvascular complications in diabetic patients and the leading cause of end-stage renal disease (ESRD). Previous studies found that immune-related genes and immune cell infiltration play important roles in the pathogenesis and development of DN. Therefore, this study aimed to explore immune-related biomarkers in DN. In this research, three microarray datasets that included 18 DN and 28 healthy tubule samples were downloaded and integrated as the training set to identify differentially expressed immune-related genes (DEIGs). A total of 63 DEIGs were identified, and most upregulated DEIGs were primarily involved in the inflammatory response and chemokine-mediated signaling pathways. The Microenvironment Cell Populations-counter (MCP-counter) algorithm was then used to estimate the abundance of infiltrated immune and stromal cell populations. According to DEIG, weighted gene coexpression network and protein–protein network analyses, CCL19 was identified as the hub immune-related biomarker. Moreover, the upregulated level of CCL19 was confirmed in other independent datasets as well as in in vitro experiments with high glucose. In summary, this study provides novel insights into the pathogenesis of diabetic nephropathy and identifies CCL19 as a potential critical gene of DN.

Role of Innate lymphoid Cells in Obesity and Insulin Resistance

Obesity, a growing chronic metabolic disease, greatly increases the risk of metabolic syndrome which includes type 2 diabetes, fatty liver and cardiovascular diseases. Obesity-associated metabolic diseases significantly contribute to mortality and reduce life expectancy. Recently, innate lymphoid cells (ILCs) have emerged as crucial regulators of metabolic homeostasis and tissue inflammation. This review focuses on the roles of ILCs in different metabolic tissues, including adipose tissue, liver, pancreas, and intestine. We briefly outline the relationship between obesity, inflammation, and insulin resistance. We then discuss how ILCs in distinct metabolic organs may function to maintain metabolic homeostasis and contribute to obesity and its associated metabolic diseases. The potential of ILCs as the therapeutic target for obesity and insulin resistance is also addressed.

Hyperoside Suppresses Renal Inflammation by Regulating Macrophage Polarization in Mice With Type 2 Diabetes Mellitus

Accumulating evidence reveals that both inflammation and lymphocyte dysfunction play a vital role in the development of diabetic nephropathy (DN). Hyperoside (HPS) or quercetin-3-O-galactoside is an active flavonoid glycoside mainly found in the Chinese herbal medicine Tu-Si-Zi. Although HPS has a variety of pharmacological effects, including anti-oxidative and anti-apoptotic activities as well as podocyte-protective effects, its underlying anti-inflammatory mechanisms remain unclear. Herein, we investigated the therapeutic effects of HPS on murine DN and the potential mechanisms responsible for its efficacy. We used C57BLKS/6J ^Lepdb/db mice and a high glucose (HG)-induced bone marrow-derived macrophage (BMDM) polarization system to investigate the potentially protective effects of HPS on DN. Our results showed that HPS markedly reduced diabetes-induced albuminuria and glomerular mesangial matrix expansion, accompanied with a significant improvement of fasting blood glucose level, hyperlipidaemia and body weight. Mechanistically, pretreatment with HPS effectively regulated macrophage polarization by shifting proinflammatory M1 macrophages (F4/80⁺CD11b⁺CD86⁺) to anti-inflammatory M2 ones (F4/80⁺CD11b⁺CD206⁺) in vivo and in bone marrow-derived macrophages (BMDMs) in vitro, resulting in the inhibition of renal proinflammatory macrophage infiltration and the reduction in expression of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor (TNF-α) and inducible nitric oxide synthase (iNOS) while increasing expression of anti-inflammatory cytokine Arg-1 and CD163/CD206 surface molecules. Unexpectedly, pretreatment with HPS suppressed CD4⁺ T cell proliferation in a coculture model of IL-4-induced M2 macrophages and splenic CD4⁺ T cells while promoting their differentiation into CD4⁺IL-4⁺ Th2 and CD4⁺Foxp3⁺ Treg cells. Taken together, we demonstrate that HPS ameliorates murine DN via promoting macrophage polarization from an M1 to M2 phenotype and CD4⁺ T cell differentiation into Th2 and Treg populations. Our findings may be implicated for the treatment of DN in clinic.

LINC00323 mediates the role of M1 macrophage polarization in diabetic nephropathy through PI3K/AKT signaling pathway

OBJECTIVE

To explore the effect of LINC00323 on the polarization of M1 macrophages in diabetic nephropathy. To study the effect and biological mechanism of LINC00323 on the occurrence and development of diabetic nephropathy.

METHODS

We used clinical samples to analyze the correlation between macrophage polarization and the occurrence and development of diabetic nephropathy. In addition, we used bioinformatics to analyze the key molecules of macrophage polarization. We then verified the key pathways that promote the M1 polarization of macrophages at the level of cell biology. And we verify the effectiveness of treatment against this target in animal experiments.

RESULTS

We analyzed in clinical samples that the expression of inflammatory factors (TNF-α and IL-6) increased in patients with diabetic nephropathy. In addition, we found that the expression of M1 marker protein CD86 increased through PCR and western blot analysis. We found a key target (LINC00323) through bioinformatics. The expression of LINC00323 in patients' blood samples is also at a high level. We further explored the mechanism of LINC00323 involved in the polarization of M1 macrophages at the level of cellular molecular biology, and found that it is closely related to the PI3K/AKT signaling pathway. In animal models, we found that inhibiting the expression of LINC00323 can reduce the damage of diabetic nephropathy.

CONCLUSION

We found that LINC00323 mediates the polarization of M1 macrophages through the PI3K/AKT signaling pathway. LINC00323 plays an important role in the occurrence and development of diabetic nephropathy.

The Roles of Kidney-Resident ILC2 in Renal Inflammation and Fibrosis

Innate lymphoid cells (ILCs) are a recently discovered lymphocyte population with high cytokine productive capacity. Type-2 ILCs (ILC2s) are the most studied, and they exert a rapid type-2 immune response to eliminate helminth infections. Massive and sustainable ILC2 activation induces allergic tissue inflammation, so it is important to maintain correct ILC2 activity for immune homeostasis. The ILC2-activating cytokine IL-33 is released from epithelial cells upon tissue damage, and it is upregulated in various kidney disease mouse models and in kidney disease patients. Various kidney diseases eventually lead to renal fibrosis, which is a common pathway leading to end-stage renal disease and is a chronic kidney disease symptom. The progression of renal fibrosis is affected by the innate immune system, including renal-resident ILC2s; however, the roles of ILC2s in renal fibrosis are not well understood. In this review, we summarize renal ILC2 function and characterization in various kidney diseases and highlight the known and potential contributions of ILC2s to kidney fibrosis.

IDO1 as a new immune biomarker for diabetic nephropathy and its correlation with immune cell infiltration

INTRODUCTION

Indoleamine 2,3-dioxygenase 1(IDO1) has complicated roles in immune-inflammatory response regulation, but its correlation with immune cell infiltration in diabetic nephropathy (DN) remains unknown.

METHODS

Gene expression data were extracted from the GEO database. Differentially expressed genes (DEGs) were identified and functional correlation analysis was performed. The immune hub gene was screened using Maximal Clique Centrality, and verified in DN model mice via western blotting, immunohistochemistry, and immunofluorescence analysis. CIBERSORTx was used to assign values to immune cell infiltration in DN and determine a correlation with the hub gene. The prognostic significance of the hub gene was then validated.

RESULTS

The 330 screened DEGs from the GEO dataset were most enriched in GO functions and KEGG pathways associated with immune inflammation. IDO1 was identified as a hub immune gene, with upregulated expression in DN model mice. IDO1 expression was positively correlated with M1 macrophages (R = 0.58, P < 0.001) and monocytes (R = 0.44, P = 0.049), and was negatively correlated with resting memory CD4 T cells (R = -0.51, P = 0.019). IDO1 expression was upregulated in peritoneal macrophages after high glucose stimulation, and inflammatory factor production was reversed by IDO1 inhibition. Higher IDO1 expression was associated with worse prognosis in DN patients via multivariate survival analysis (P < 0.001).

CONCLUSIONS

IDO1 was identified as a diagnostic and prognostic biomarker for DN and shown to play a vital role in immune cell infiltration in DN, ascertained using microarray data and CIBERSORTx for the first time.

Hybrid cytokine IL233 renders protection in murine acute graft vs host disease (aGVHD)

Previously, we generated IL233, a hybrid cytokine composed of interleukin (IL)-2 and IL-33, with better therapeutic potential than either cytokine in multiple inflammatory diseases, in part through promoting T-regulatory cells (Tregs). Here we test the potential of IL233 pretreatment in a murine model of excessive Th1 activation, the parent-into-F1 model of acute GVHD (aGVHD). Five days of IL233 pretreatment of the recipients blocked or delayed the aGVHD-linked loss of B cells as seen in either the peripheral blood (day-11) or lymph nodes (day-14). IL233 pretreatment also prevented the expansion of donor CD8 T-cells in blood and LN at day-14 and significantly reduced day-14 serum IFNγ and TNFα compared to saline treated GVHD mice although, the level of Tregs did not statistically differ between saline and IL233-treated mice. Overall, the current study provides support for the use of IL233 as a therapeutic option in excessive Th1/CD8-driven conditions.

The effect of probiotics on lipid profile & anthropometric indices in diabetic nephropathy; a systematic review and meta-analysis of clinical trials

Purpose

Recent trials have demonstrated the possible improvements in lipid profile & anthropometric indices after probiotics supplementation. We aimed to reanalyze the related literature to explore the efficacy of probiotics in Diabetic Nephropathy (DN) patients.

Methods

PubMed, Embase, Web of science, google scholar, Scopus, and Cochrane Library databases were systematically searched to find the related data on diabetic nephropathy population. All Randomized controlled trials (RCTs) that investigated the effect of probiotics on serum lipid markers (High-Density Lipoprotein [HDL], Triglyceride, Total Cholesterol, TC-to-HDL ratio, Low-Density Lipoprotein, Very Low-Density Lipoprotein) and anthropometric indices (Body Weight, Body Mass Index, waist-to-hip ratio) were included (PROSPERO No.CRD42020186189). Meta-analysis was performed using the random-effect model.

Results

Of 156 studies, seven were eligible for inclusion. Lipid biomarkers had a marginal reduction (except for HDL; WMD = 2.59 mg/dl; 95% CI = -0.28, 5.47; P = 0.077); whereas anthropometric indices increased in a non-significant manner.

Conclusion

There is limited evidence to support the efficacy of probiotics for the modulation of lipid profile and anthropometric indices in DN patients.

Graphical abstract

Probiotics did not beneficial effect on lipid profile & anthropometric markers in Diabetic Nephropathy; anyway, more trials should be conducted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00765-8.

Immunomodulatory Approaches in Diabetes-Induced Cardiorenal Syndromes

Immunomodulatory approaches are defined as all interventions that modulate and curb the immune response of the host rather than targeting the disease itself with the aim of disease prevention or treatment. A better understanding of the immune system continues to offer innovative drug targets and methods for immunomodulatory interventions. Cardiorenal syndrome is a clinical condition that defines disorders of the heart and kidneys, both of which communicate with one another through multiple pathways in an interdependent relationship. Cardiorenal syndrome denotes the confluence of heart-kidney relationships across numerous interfaces. As such, a dysfunctional heart or kidney has the capacity to initiate disease in the other organ via common hemodynamic, neurohormonal, immunological, and/or biochemical feedback pathways. Understanding how immunomodulatory approaches are implemented in diabetes-induced cardiovascular and renal diseases is important for a promising regenerative medicine, which is the process of replacing cells, tissues or organs to establish normal function. In this article, after a brief introduction on the immunomodulatory approaches in diseases, we will be reviewing the epidemiology and classifications of cardiorenal syndrome. We will be emphasizing on the hemodynamic factors and non-hemodynamic factors linking the heart and the kidneys. In addition, we will be elaborating on the immunomodulatory pathways involved in diabetes-induced cardiorenal syndrome namely, RAS, JAK/STAT, and oxidative stress. Moreover, we will be addressing possible therapeutic approaches that target the former pathways in an attempt to modulate the immune system.

Mini-Review: GSDME-Mediated Pyroptosis in Diabetic Nephropathy

Pyroptosis is a recently identified type of lytic programmed cell death, in which pores form in the plasma membrane, and cells swell, rupture, and then release their contents, including inflammatory cytokines. Molecular studies indicated that pyroptosis may occur via a gasdermin D (GSDMD) and caspase-1 (Casp1) -dependent classical pathway, a GSDMD and Casp11/4/5-dependent non-classical pathway, or a gasdermin E (GSDME) and Casp3-dependent pathway. Studies of animal models and humans indicated that pyroptosis can exacerbate several complications of diabetes, including diabetic nephropathy (DN), a serious microvascular complication of diabetes. Many studies investigated the mechanism mediating the renoprotective effect of GSDMD regulation in the kidneys of patients and animal models with diabetes. As a newly discovered regulatory mechanism, GSDME and Casp3-dependent pyroptotic pathway in the progression of DN has also attracted people's attention. Z-DEVD-FMK, an inhibitor of Casp3, ameliorates albuminuria, improves renal function, and reduces tubulointerstitial fibrosis in diabetic mice, and these effects are associated with the inhibition of GSDME. Studies of HK-2 cells indicated that the molecular and histological features of secondary necrosis were present following glucose stimulation due to GSDME cleavage, such as cell swelling, and release of cellular contents. Therefore, therapies targeting Casp3/GSDME-dependent pyroptosis have potential for treatment of DN. A novel nephroprotective strategy that employs GSDME-derived peptides which are directed against Casp3-induced cell death may be a key breakthrough. This mini-review describes the discovery and history of research in this pyroptosis pathway and reviews the function of proteins in the gasdermin family, with a focus on the role of GSDME-mediated pyroptosis in DN. Many studies have investigated the impact of GSDME-mediated pyroptosis in kidney diseases, and these studies used multiple interventions, in vitro models, and in vivo models. We expect that further research on the function of GDSME in DN may provide valuable insights that may help to improve treatments for this disease.

Activated mesangial cells acquire the function of antigen presentation

Mesangial cells (MCs), as resident cells of the kidneys, play an important role in maintaining glomerular function. MCs are located between the capillary loops of the glomeruli and mainly support the capillary plexus, constrict blood vessels, extracellular matrix components, produce cytokines, and perform phagocytosis and clearance of macromolecular substances. When the glomerular environment changes, MCs are often affected, which can lead to functional transformation. The immune response is involved in the occurrence and development of various kidney diseases, in these diseases, antigen-presenting cells (APCs) play an important role. APCs can present antigens to T lymphocytes, causing them to become activated and proliferate. Studies have shown that MCs have phagocytic function and express APC markers on the cell surface. Additionally, MCs are stimulated by or produce various inflammatory factors to participate in the renal inflammatory response. Therefore, MCs have potential antigen presentation function and participate in the pathological changes of various kidney diseases as APCs upon activation. In this paper, by reviewing MC phagocytic function, activated MC expression of APC surface markers, and MC participation in the inflammatory response and local renal immune response, we confirm that activated MCs can act as APCs in renal disease.

Innate lymphoid cells in kidney diseases

It is well known that innate immune cells, including dendritic cells, macrophages, and natural killer cells, contribute to pathogenesis and protection in various kidney diseases. The understanding of innate immunity has been advanced recently by the discovery of a new group of innate lymphoid cells (ILCs), including ILC1, ILC2, and ILC3. ILCs lack adaptive antigen receptors, yet can be triggered by various pathogens and rapidly provide an abundant source of immunomodulatory cytokines to exert immediate immune reactions and direct subsequent innate and adaptive immune responses. ILCs play critical roles in immunity, tissue homeostasis, and pathological inflammation. In this review, we highlight the biological function of ILC subpopulations in the normal kidney, and their important roles in acute and chronic kidney diseases, thus demonstrating the emerging importance of ILC-regulated immunity in this special organ and providing insights for future research directions and therapeutic interventions.

Quantitative levels of serum N-glycans in type 1 diabetes and their association with kidney disease

We investigated associations of quantitative levels of N-glycans with hemoglobin A1c (HbA1c), renal function and renal function decline in type 1 diabetes. We measured 46 total N-glycan peaks (GPs) on 1565 serum samples from the Scottish Diabetes Research Network Type 1 Bioresource Study (SDRNT1BIO) and a pool of healthy donors. Quantitation of absolute abundance of each GP used 2AB-labeled mannose-3 as a standard. We studied cross-sectional associations of GPs and derived measures with HbA1c, albumin/creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR), and prospective associations with incident albuminuria and final eGFR. All GPs were 1.4 to 3.2 times more abundant in SDRTN1BIO than in the healthy samples. Absolute levels of all GPs were slightly higher with higher HbA1c, with strongest associations for triantennary trigalactosylated disialylated, triantennary trigalactosylated trisialylated structures with core or outer arm fucose, and tetraantennary tetragalactosylated trisialylated glycans. Most GPs showed increased abundance with worsening ACR. Lower eGFR was associated with higher absolute GP levels, most significantly with biantennary digalactosylated disialylated glycans with and without bisect, triantennary trigalactosylated trisialylated glycans with and without outer arm fucose, and core fucosylated biantennary monogalactosylated monosialylated glycans. Although several GPs were inversely associated prospectively with final eGFR, cross-validated multivariable models did not improve prediction beyond clinical covariates. Elevated HbA1c is associated with an altered N-glycan profile in type 1 diabetes. Although we could not establish GPs to be prognostic of future renal function decline independently of HbA1c, further studies to evaluate their impact in the pathogenesis of diabetic kidney disease are warranted.

Gut Microbiota as a Trigger for Metabolic Inflammation in Obesity and Type 2 Diabetes

The gut microbiota has been linked to the development of obesity and type 2 diabetes (T2D). The underlying mechanisms as to how intestinal microbiota may contribute to T2D are only partly understood. It becomes progressively clear that T2D is characterized by a chronic state of low-grade inflammation, which has been linked to the development of insulin resistance. Here, we review the current evidence that intestinal microbiota, and the metabolites they produce, could drive the development of insulin resistance in obesity and T2D, possibly by initiating an inflammatory response. First, we will summarize major findings about immunological and gut microbial changes in these metabolic diseases. Next, we will give a detailed view on how gut microbial changes have been implicated in low-grade inflammation. Lastly, we will critically discuss clinical studies that focus on the interaction between gut microbiota and the immune system in metabolic disease. Overall, there is strong evidence that the tripartite interaction between gut microbiota, host immune system and metabolism is a critical partaker in the pathophysiology of obesity and T2D.

The Yin and Yang of Alarmins in Regulation of Acute Kidney Injury

Acute kidney injury (AKI) is a major clinical burden affecting 20 to 50% of hospitalized and intensive care patients. Irrespective of the initiating factors, the immune system plays a major role in amplifying the disease pathogenesis with certain immune cells contributing to renal damage, whereas others offer protection and facilitate recovery. Alarmins are small molecules and proteins that include granulysins, high-mobility group box 1 protein, interleukin (IL)-1α, IL-16, IL-33, heat shock proteins, the Ca++ binding S100 proteins, adenosine triphosphate, and uric acid. Alarmins are mostly intracellular molecules, and their release to the extracellular milieu signals cellular stress or damage, generally leading to the recruitment of the cells of the immune system. Early studies indicated a pro-inflammatory role for the alarmins by contributing to immune-system dysregulation and worsening of AKI. However, recent developments demonstrate anti-inflammatory mechanisms of certain alarmins or alarmin-sensing receptors, which may participate in the prevention, resolution, and repair of AKI. This dual function of alarmins is intriguing and has confounded the role of alarmins in AKI. In this study, we review the contribution of various alarmins to the pathogenesis of AKI in experimental and clinical studies. We also analyze the approaches for the therapeutic utilization of alarmins for AKI.

Roles of kininogen-1, basement membrane specific heparan sulfate proteoglycan core protein, and roundabout homolog 4 as potential urinary protein biomarkers in diabetic nephropathy

Diabetic nephropathy, a major complication of diabetes mellitus (DM), is increasing worldwide and the large majority of patients have type 2 DM. Microalbuminuria has been used as a diagnostic marker of diabetic nephropathy. But owing to its insufficient sensitivity and specificity, other biomarkers are being sought. In addition, the pathophysiology of diabetic nephropathy is not fully understood and declines in renal function occur even without microalbuminuria. In this study, we investigated urinary proteins from three study groups (controls, and type 2 diabetic subjects with or without microalbuminuria). Non-targeted label-free Nano-LC QTOF analysis was conducted to discover underlying mechanisms and protein networks, and targeted label-free Nano-LC QTOF with SWATH was performed to qualify discovered protein candidates. Twenty-eight proteins were identified as candidates and functionally analyzed via String DB, gene ontology and pathway analysis. Four predictive mechanisms were analyzed: i) response to stimulus, ii) platelet activation, signaling and aggregation, iii) ECM-receptor interaction, and iv) angiogenesis. These mechanisms can provoke kidney dysfunction in type 2 diabetic patients via endothelial cell damage and glomerulus structural alteration. Based on these analyses, three proteins (kininogen-1, basement membrane-specific heparan sulfate proteoglycan core protein, and roundabout homolog 4) were proposed for further study as potential biomarkers. Our findings provide insights that may improve methods for both prevention and diagnosis of diabetic nephropathy.

Emerging Roles of Interleukin-33-responsive Kidney Group 2 Innate Lymphoid Cells in Acute Kidney Injury

Interleukin (IL)-33, a member of the IL-1 family of cytokines, is involved in innate and adaptive immune responses. IL-33 triggers pleiotropic immune functions in multiple types of immune cells, which express the IL-33 receptor, ST2. Recent studies have revealed the potential applications of IL-33 for treating acute kidney injury in preclinical animal models. However, IL-33 and IL-33-responding immune cells are reported to exhibit both detrimental and beneficial roles. The IL-33-mediated immunomodulatory functions have been investigated using loss-of-function approaches, such as IL33-deficient mice, IL-33 antagonists, or administration of exogenous IL-33 recombinant protein. This review will discuss the key findings on IL-33-mediated activation of kidney resident group 2 innate lymphoid cells (ILC2s) and summarize the current understanding of the differential functions of endogenous IL-33 and exogenous IL-33 and their potential implications in treating acute kidney injury.

Interleukin-1 Family Cytokines: Keystones in Liver Inflammatory Diseases

The pyrogenic property being the first activity described, members of the interleukin-1 superfamily (IL-1α, IL-1β, IL-18, and the newest members: IL-33, IL-36, IL-37, and IL-38) are now known to be involved in several inflammatory diseases such as obesity, atherosclerosis, cancer, viral and parasite infections, and auto-inflammatory syndromes as well as liver diseases. Inflammation processes are keystones of chronic liver diseases, of which the etiology may be viral or toxic, as in alcoholic or non-alcoholic liver diseases. Inflammation is also at stake in acute liver failure involving massive necrosis, and in ischemia-reperfusion injury in the setting of liver transplantation. The role of the IL-1 superfamily of cytokines and receptors in liver diseases can be either protective or pro-inflammatory, depending on timing and the environment. Our review provides an overview of current understanding of the IL-1 family members in liver inflammation, highlighting recent key investigations, and therapeutic perspectives. We have tried to apply the concept of trained immunity to liver diseases, based on the role of the members of the IL-1 superfamily, first of all IL-1β but also IL-18 and IL-33, in modulating innate lymphoid immunity carried by natural killer cells, innate lymphoid cells or innate T-αβ lymphocytes.