Innate immunity in diabetes and diabetic nephropathy. Nat Rev Nephrol. 2016;12:13-26. [PMID: 26568190 DOI: 10.1038/nrneph.2015.175]

Resatorvid Relieves Breast Cancer Complicated with Depression by Inactivating Hippocampal Microglia Through TLR4/NF-κB/NLRP3 Signaling Pathway

Background

Breast cancer is one of the most common cancer with high risk in females all over the world. It is usually complicated with depression, which can further accelerate the development and progression of breast tumors. We aim to identify a new drug and identify its functional mechanism in the regulation of hippocampal microglia (MG) in breast cancer complicated with depression (BCCD).

Methods

The activation model of MG was established by treatments from corticosterone (CORT) or lipopolysaccharides (LPS). The inhibitory effects of resatorvid on MG were investigated by CCK-8, ROS, immunofluorescence, TUNEL, scratch test, ELISA, RT-qPCR and Western blot. BCCD animal model was established using 4T1 inflammatory breast cancer cells and CORT treatment in vitro. Open field experiment (OFE), tail suspension test (TST), ELISA, RT-qPCR and Western blot experiments were utilized to examine the effects of resatorvid on the animal model in vivo.

Results

The cell viability and migration ability of the BCCD model group were suppressed. The expressions of inflammatory factors, ROS, and the apoptotic rate of the BCCD model group were up-regulated, in contrast to the control group. The expressions related to the TLR4/NF-κB/NLRP3 signaling in the BCCD model group were also elevated. Resatorvid reversed the above changes, which showed good therapeutic effects in depression-related behavioral changes, tumor treatment, and blood–brain barrier function.

Conclusion

In summary, resatorvid inhibited the activation of hippocampal MG in BCCD by regulating TLR4/NF-κB/NLRP3 signaling pathway.

Decreased miR-132 plays a crucial role in diabetic encephalopathy by regulating the GSK-3β/Tau pathway

Diabetic encephalopathy (DE) is a global concern and Gordian knot worldwide. miRNA-132 (miR-132) is a class of negative gene regulators that promote diabetic pathologic mechanisms and its complications. However, the molecular mechanisms of miR-132 in DE are elusive, thus an alternative therapeutic strategy is urgently in demand. The present study explored the protective effect and the underlying mechanism of miR-132 on DE via the GSK-β/Tau signaling pathway. Experimentally, a type 2 DM rat model was developed by incorporating a high-fat diet and streptozotocin injection. Further, the DE model was screened via the Morris Water Maze test. Primary hippocampal neurons and HT-22 cells were used for in vitro analysis. We found that hyperglycemia exacerbates cognitive impairment in T2DM rats. When we isolated the primary hippocampus neurons, the expression of miR-132 RNA was low in both the DE hippocampus and primary neurons. GSK-3β and Tau 404 were highly expressed in injured HT-22 cells and diabetic hippocampal tissues. miR-132 downregulated the expression of GSK-3β. Besides, a binding and colocalized relationship between GSK3β and Tau was also reported. These findings suggest that miR-132 exerts protective effects from DE injury by repressing GSK-3β expression and alleviating Tau hyperphosphorylation in HT-22 cells and hippocampus tissues.

A novel salviadione derivative, compound 15a, attenuates diabetes-induced renal injury by inhibiting NF-κB-mediated inflammatory responses

Diabetic nephropathy is the leading cause of renal failure worldwide. Elevated inflammatory signaling has been shown to lead to deterioration of renal function in human and experimental diabetes. We recently developed a salviadione derivative (compound 15a) that prevented microbial lipopolysaccharide-induced inflammatory responses, which are largely driven by nuclear factor-κB (NF-κB). In the present study, we have tested the hypothesis that 15a will protect kidneys from diabetes-induced dysfunction by suppressing NF-κB activation and inflammatory signaling. Treatment of diabetic mice with 15a inhibited diabetes-induced renal fibrosis, NF-κB activation, and upregulation of proinflammatory cytokines. Histologically, kidney specimens from diabetic mice treated with 15a were indistinguishable from non-diabetic controls. We confirmed our findings in cultured renal tubular epithelial cells exposed to high levels of glucose. In these cultured cells, 15a pretreatment prevented high glucose-induced NF-κB activation and expression of inflammatory cytokines. These protective effects were also reflected in reduced levels of proteins involved in matrix expansion. Overall, our studies show that a salviadione derivative, 15a, is effective in suppressing diabetes-induced NF-κB activation and inflammatory signaling.

Isoliquiritigenin prevents hyperglycemia-induced renal injuries by inhibiting inflammation and oxidative stress via SIRT1-dependent mechanism

Diabetic nephropathy (DN) as a global health concern is closely related to inflammation and oxidation. Isoliquiritigenin (ISL), a natural flavonoid compound, has been demonstrated to inhibit inflammation in macrophages. Herein, we investigated the effect of ISL in protecting against the injury in STZ-induced type 1 DN and in high glucose-induced NRK-52E cells. In this study, it was revealed that the administration of ISL not only ameliorated renal fibrosis and apoptosis, but also induced the deterioration of renal function in diabetic mice. Mediated by MAPKs and Nrf-2 signaling pathways, respectively, upstream inflammatory response and oxidative stress were neutralized by ISL in vitro and in vivo. Moreover, as further revealed by the results of molecular docking, sirtuin 1 (SIRT1) binds to ISL directly, and the involvement of SIRT1 in ISL-mediated renoprotective effects was confirmed by studies using in vitro models of SIRT1 overexpression and knockdown. In summary, by reducing inflammation and oxidative stress, ISL has a significant pharmacological effect on the deterioration of DN. The benefits of ISL are associated with the direct binding to SIRT1, the inhibition of MAPK activation, and the induction of Nrf-2 signaling, suggesting the potential of ISL for DN treatment.

Toll-like Receptors as Potential Therapeutic Targets in Kidney Diseases

Toll-like Receptors (TLRs) are members of pattern recognition receptors and serve a pivotal role in host immunity. TLRs response to pathogen-associated molecular patterns encoded by pathogens or damage-associated molecular patterns released by dying cells, initiating an inflammatory cascade, where both beneficial and detrimental effects can be exerted. Accumulated evidence has revealed that TLRs are closely associated with various kidney diseases but their roles are still not well understood. This review updated evidence on the roles of TLRs in the pathogenesis of kidney diseases including urinary tract infection, glomerulonephritis, acute kidney injury, transplant allograft dysfunction and chronic kidney diseases.

Silencing TLR4/MyD88/NF-κB Signaling Pathway Alleviated Inflammation of Corneal Epithelial Cells Infected by ISE

The regulatory role of toll-like receptor 4 (TLR4) in the inactivate staphylococcus epidermidis (ISE)-induced cornea inflammation is not well investigated. Here, TLR4 silence could decrease inflammatory cytokines in corneal epithelial cells treated with ISE. The mouse corneal epithelial cells were exposed to ISE for 24 h, either alone or with the NF-κB inhibitor, TLR4 lentivirus to bilaterally (knock-down or and overexpression). The expression of TLR4 in mouse corneal epithelial cells was investigated using western blot and qRT-PCR assay. The inflammatory cytokine levels were evaluated by qRT-PCR and ELISA, respectively. The relative impact factors of TLR4-mediated NF-κB signaling detected using western blot assay. Results show the expression levels of TLR4 and some inflammatory cytokines were significantly increased in corneal epithelial cells treated with ISE. TLR4 Silence markedly decreased ISE-induced production of IL12, TNF-α, CCL5, and CCL9 in corneal epithelial cells. Furthermore, the nuclear translocation of NF-κB p65 and myeloid differentiation protein 88 (MyD88) in the cells treated with ISE were further reduced by silencing TLR4. Inhibition of TLR4-mediated NF-κB signaling by using BAY11-7082 also alleviated ISE-induced inflammation. In the rescue experiment, transfected the stable TLR4 silenced corneal epithelial cells with TLR4 overexpression lentivirus, we found that TLR4 overexpression can restore the down-regulation of TLR4 and inflammatory cytokines (IL12, TNF-α, CCL9) caused by TLR4 knocked down. Therefore, ISE-induced cornea inflammation was due to the activation of the TLR4/MyD88/NF-κB signaling pathway, and dramatically stimulated IL12, TNF-α, CCL9 secretion. TLR4 silence presented mitigates damage in corneal epithelial cells treated with ISE.

Urinary proteins detected using modern proteomics intervene in early type 2 diabetic kidney disease – a pilot study

Aim: An advanced proteomics platform for protein biomarker discovery in diabetic chronic kidney disease (DKD) was developed, validated and implemented. Materials & methods: Three Type 2 diabetes mellitus patients and three control subjects were enrolled. Urinary peptides were extracted, samples were analyzed on a hybrid LTQ-Orbitrap Velos Pro instrument. Raw data were searched using the SEQUEST algorithm and integrated into Proteome Discoverer platform. Results & discussion: Unique peptide sequences, resulted sequence coverage, scoring of peptide spectrum matches were reported to albuminuria and databases. Five proteins that can be associated with early DKD were found: apolipoprotein AI, neutrophil gelatinase-associated lipocalin, cytidine deaminase, S100-A8 and hemoglobin subunit delta. Conclusion: Urinary proteome analysis could be used to evaluate mechanisms of pathogenesis of DKD.

Pattern recognition receptor-mediated inflammation in diabetic vascular complications

The innate immune system contains multiple classes of pattern recognition receptors (PRRs), which recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) in the intracellular and extracellular space. Although PRRs are indispensable for the detection and clearance of invading pathogens, dysregulated PRR activation by extrinsic and intrinsic factors leads to inflammatory diseases. PRR-mediated inflammation has been shown to play a pivotal role in the pathogenesis of diabetic vascular complications (DVCs), which are the leading causes of morbidity and mortality in diabetic patients. Upon sensing hyperglycemia-generated DAMPs, PRRs activate intracellular signaling pathways leading to the production of proinflammatory cytokines and chemokines in various cells of the kidney, brain, eye, and heart. The resulting chronic, low-grade inflammation contributes to DVCs. In this review, we summarize the role of PRRs in DVCs including diabetic nephropathy, neuropathy, retinopathy, and cardiomyopathy. We propose that targeting PRRs and associated signaling pathways may be beneficial for the management of DVCs.

Recent advances in drug discovery for diabetic kidney disease

INTRODUCTION

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease (ESRD), and 40% of patients with diabetes develop DKD. Although some pathophysiological mechanisms and drug targets of DKD have been described, the effectiveness or clinical usefulness of such treatment has not been well validated. Therefore, searching for new targets and potential therapeutic candidates has become an emerging research area.

AREAS COVERED

The pathophysiological mechanisms, new drug targets and potential therapeutic compounds for DKD are addressed in this review.

EXPERT OPINION

Although preclinical and clinical evidence has shown some positive results for controlling DKD progression, treatment regimens have not been well developed to reduce the mortality in patients with DKD globally. Therefore, the discovery of new therapeutic targets and effective target-based drugs to achieve better and safe treatment are urgently required. Preclinical screening and clinical trials for such drugs are needed.

The potential of artemisinins as anti-obesity agents via modulating the immune system

Artemisinin and its derivatives are the most effective antimalarial drugs. Besides anti-malarial activity, artemisinin and its derivatives have displayed wide-spectrum bioactivities such as anti-parasite, anti-tumor, and anti-obesity effects. Obesity is an epidemic worldwide which is a big threat to human health, but there are only a few approved anti-obesity drugs in the world. Also, these drugs are efficient to limited patients partly because their safety and efficacy are questioned. Anti-inflammatory therapies may be valuable in obesity treatment since growing evidence shows chronic metabolic inflammation is implicated in metabolic disease pathogenesis. As artemisinin and its derivatives display effective anti-inflammatory and immunoregulatory properties with less toxicity, it provides an insight for novel drug development in obesity therapeutic strategies via immune-regulatory mechanisms. In this review, the potential of artemisinin and its derivatives to treat various metabolic diseases such as obesity and diabetes is discussed.

Metabolism-Associated Molecular Patterns (MAMPs)

Metabolic diseases pose a tremendous health threat in both developed and developing countries. The pathophysiology of metabolic diseases is complex but has been shown to be closely associated with sterile inflammation, which is initiated by various danger molecules derived from metabolic overload, such as oxidized low-density lipoproteins (OxLDLs), free fatty acids (FFAs), glucose, advanced glycation end products (AGEs), and cholesterol. These danger signals are sensed by pattern recognition receptors (PRRs) to activate proinflammatory signaling pathways and promote the release of proinflammatory mediators, leading to chronic low-grade inflammation. Although these harmful metabolic stimuli are generally regarded as damage-associated molecular patterns (DAMPs), a more specific definition and accurate classification for these DAMPs is still missing. In this opinion, we classify the harmful metabolic stimuli that can incite inflammatory responses and tissue damage via instigating PRRs as metabolism-associated molecular patterns (MAMPs), and we summarize their roles in metaflammation-mediated metabolic diseases.

Lung fibroblasts produce IL-33 in response to stimulation with retinoblastoma-binding protein 9 via production of prostaglandin E2

Intestinal nematode infection induces pulmonary eosinophilia via IL-33, although the mechanism of pulmonary IL-33 induction remains unclear. Because nematode migration damages lungs, we speculated that lung-derived damage-associated molecular patterns (DAMPs) possess an IL-33-inducing activity (IL33ia). Indeed, intra-nasal administration of a lung extract induced IL-33 production in lungs. Additionally, lung extracts increased Il33 mRNA expression in primary lung fibroblasts. Proteomic analysis identified retinoblastoma-binding protein 9 (RBBP9) as a major DAMP with IL33ia. RBBP9 was originally discovered as a protein that provides cells with resistance to the growth inhibitory effect of transforming growth factor (TGF)-β1. Here, we found that stimulation by RBBP9 induced primary fibroblasts to produce prostaglandin E2 (PGE2) that, in turn, induced fibroblasts to produce IL-33. RBBP9-activated fibroblasts expressed mRNAs of cyclooxygenase-2 (COX-2) and PGE2 synthase-1 that convert arachidonic acid to PGE2. Furthermore, they expressed PGE2 receptors E-prostanoid (EP) 2 and EP4. Thus, treatment with a COX-2 inhibitor or EP2 and/or EP4 receptor antagonists inhibited RBBP9-induced IL-33 production. Nematode infection induced pulmonary Il33 mRNA expression, which was inhibited by the COX-2 inhibitor or EP2 and EP4 antagonists, suggesting that nematode infection induced pulmonary Il33 mRNA via PGE2. RBBP9 was expressed constitutively in the lung in the steady state, which did not increase after nematode infection. Finally, we found that Rbbp9-deficient mice had a significantly diminished capacity to increase pulmonary Il33 mRNA expression following nematode infection. Thus, the PGE2-EP2/EP4 pathway activated by RBBP9 released from damaged lungs is important for pulmonary IL-33 production in nematode-infected animals.

circACTR2: A Novel Mechanism Regulating High Glucose-Induced Fibrosis in Renal Tubular Cells via Pyroptosis

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease. Current therapies for DKD are insufficient. Therefore, there is an urgent need for identifying new therapies. An increasing number of micro RNAs (miRNAs) and long noncoding RNAs (lncRNAs) have been demonstrated to modulate the progression of diabetic kidney disease. Nevertheless, until now, there have been few reports evaluating the relevance of circular RNAs (circRNAs) in DKD. circRNAs have been reported to regulate the occurrence and development of multiple diseases. In this study, we intended to explore the circRNA expression profiles and determine the role of circRNA in DKD. We identified a series of dysregulated circRNAs in glucose-stressed HK-2 cells using circRNA microarray analysis. Among the candidate circRNAs, we found that circACTR2 was upregulated and may be involved in inflammation and pyroptosis. Knockdown of circACTR2 significantly decreased pyroptosis, interleukin (IL)-1β release and collagen IV and fibronectin production, indicating the effective regulation by circACTR2 of cell death and inflammation. Overall, our study identified a new circRNA, circACTR2, that regulates high glucose-induced pyroptosis, inflammation and fibrosis in proximal tubular cells. The present study preliminarily explores the role of circRNAs in pyroptosis of tubular cells, and provides novel insight into the pathogenesis of DKD and new therapeutic strategies.

Study on metabonomics of Chinese herbal medicine in the treatment of type 2 diabetes mellitus complicated with community-acquired pneumonia

INTRODUCTION

Community-acquired pneumonia (CAP) is the main acute complication of type 2 diabetes mellitus (T2DM) and the main cause of hospitalization for infectious diseases. Unfortunately, in the treatment of type 2 diabetes mellitus complicated with community-acquired pneumonia (T2DM-CAP), modern medicine is still faced with enormous challenges because of insulin resistance and drug-resistant bacteria. In recent decades, clinical and experimental evidence shows that Chinese herbal medicine (CHM) has a certain beneficial effect on diabetes and pneumonia. Therefore, this trial aims to assess the efficacy and safety of CHM plus western medicines for the treatment of T2DM-CAP.

METHODS

We propose a double-blind, placebo-controlled, randomized superiority trial.A total of 92 participants with T2DM-CAP will be randomly allocated at a 1:1 ratio to either the experimental group, which will receive modified Ban-Xia-Xie-Xin-Decotion and basic treatment, or the control group, which will receive basic treatment only. The study duration will be 14 days. The primary outcome will be the total clinical effective rate. The secondary outcomes are traditional Chinese medicine symptom score scale, pneumonia severity index, usage time of antibiotic, time required for blood sugar to reach the required level, frequency of hypoglycemia, and chest CT. Liquid chromatograph-mass spectrometry method will be used to explore the blood metabolism profiles of the subjects, to explore the pathogenesis of T2DM-CAP and the mechanism of CHM on T2DM-CAP. Adverse events will also be evaluated.

DISCUSSION

This trial will provide evidence of the effectiveness and safety of traditional CHM in treating patients with T2DM-CAP.

TRIAL REGISTRATION NUMBER

ChiCTR2000035204.

Mitochondria-Associated Endoplasmic Reticulum Membranes (MAMs) and Their Prospective Roles in Kidney Disease

Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) serve as essential hubs for interorganelle communication in eukaryotic cells and play multifunctional roles in various biological pathways. A defect in ER-mitochondria signaling or MAMs dysfunction has pleiotropic effects on a variety of intracellular events, which results in disturbances of the mitochondrial quality control system, Ca2+ dyshomeostasis, apoptosis, ER stress, and inflammasome activation, which all contribute to the onset and progression of kidney disease. Here, we review the structure and molecular compositions of MAMs as well as the experimental methods used to study these interorganellar contact sites. We will specifically summarize the downstream signaling pathways regulated by MAMs, mainly focusing on mitochondrial quality control, oxidative stress, ER-mitochondria Ca2+ crosstalk, apoptosis, inflammasome activation, and ER stress. Finally, we will discuss how alterations in MAMs integrity contribute to the pathogenesis of kidney disease and offer directions for future research.

Protective factors as biomarkers and targets for prevention and treatment of diabetic nephropathy: From current human evidence to future possibilities

Although hyperglycemia, high blood pressure and aging increase the risk of developing kidney complications, some diabetes patients exposed to these risk factors do not develop kidney disease, suggesting the presence of endogenous protective factors. There is a growing need to understand these factors determining protection of the kidney in order to improve the design of preventive strategies and to enhance the processes responsible for renoprotection. The aim of this review was to present the existing molecular and epidemiological data on factors showing protective effects in diabetic kidney disease, and to summarize the evidence regarding their potential in the area of future clinical diagnostics, therapeutics and early preventive strategies. These include transcriptomic and proteomic studies regarding the anti-inflammatory, anti-fibrotic and regenerative factors that were associated with slower progression of renal function loss. Another focus is the new evidence regarding the evaluation of alterations in the regulatory epigenome and its involvement in the risk of diabetic kidney disease. Further effort is required to validate and extend these findings, and to define their potential for clinical implementation in the future.

Anti-inflammatory, antioxidant and renoprotective effects of SOCS1 mimetic peptide in the BTBR ob/ob mouse model of type 2 diabetes

INTRODUCTION

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease worldwide. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway participates in the development and progression of DN. Among the different mechanisms involved in JAK/STAT negative regulation, the family of suppressor of cytokine signaling (SOCS) proteins has been proposed as a new target for DN. Our aim was to evaluate the effect of SOCS1 mimetic peptide in a mouse model of obesity and type 2 diabetes (T2D) with progressive DN.

RESEARCH DESIGN AND METHODS

Six-week-old BTBR (black and tan brachyuric) mice with the ob/ob (obese/obese) leptin-deficiency mutation were treated for 7 weeks with two different doses of active SOCS1 peptide (MiS1 2 and 4 µg/g body weight), using inactive mutant peptide (Mut 4 µg) and vehicle as control groups. At the end of the study, the animals were sacrificed to obtain blood, urine and kidney tissue for further analysis.

RESULTS

Treatment of diabetic mice with active peptide significantly decreased urine albumin to creatinine ratio by up to 50%, reduced renal weight, glomerular and tubulointerstitial damage, and restored podocyte numbers. Kidneys from treated mice exhibited lower inflammatory infiltrate, proinflammatory gene expression and STAT activation. Concomitantly, active peptide administration modulated redox balance markers and reduced lipid peroxidation and cholesterol transporter gene expression in diabetic kidneys.

CONCLUSION

Targeting SOCS proteins by mimetic peptides to control JAK/STAT signaling pathway ameliorates albuminuria, morphological renal lesions, inflammation, oxidative stress and lipotoxicity, and could be a therapeutic approach to T2D kidney disease.

Proposed Neuroimmune Roles of Dimethyl Fumarate, Bupropion, S-Adenosylmethionine, and Vitamin D3 in Affording a Chronically Ill Patient Sustained Relief from Inflammation and Major Depression

We had discussed earlier that, after most of the primary author's multiple sclerosis (MS) symptoms were lessened by prior neuroimmune therapies, use of dimethyl fumarate (DMF) gradually subdued his asthma and urticaria symptoms, as well as his MS-related intercostal cramping; and bupropion supplemented with S-adenosylmethionine (SAMe) and vitamin D3 (vit-D3) helped remit major depression (MD). Furthermore, the same cocktail (bupropion plus supplements), along with previously discussed routines (yoga, meditation, physical exercises, and timely use of medications for other illnesses), continued to subdue MD during new difficulties with craniopharyngioma, which caused bitemporal vision loss; sphenoid sinus infections, which caused cranial nerve-VI (CN6) palsy and diplopia; and through their treatments. Impressed by the benefit the four compounds provided, in this manuscript, we focus on explaining current neuroimmune literature proposals on how: (1) DMF impedes inflammation, oxidative stress, and cell death in CNS and peripheral tissues; (2) Bupropion curbs anxiety, MD, and enhances alertness, libido, and moods; (3) SAMe silences oxidative stress and depression by multiple mechanisms; and (4) Vit-D3 helps brain development and functioning and subdues inflammation. we realize that herein we have reviewed proposed mechanisms of remedies we discovered by literature searches and physician assisted auto-experimentation; and our methods might not work with other patients. We present our experiences so readers are heartened to reflect upon their own observations in peer-reviewed forums and make available a wide body of information for the chronically ill and their physicians to benefit from.

Targeting NLRP3 inflammasome as a promising approach for treatment of diabetic nephropathy: Preclinical evidences with therapeutic approaches

Diabetes mellitus is an increasingly prevalent disease around the globe. The epidemic of diabetes mellitus and its complications pretenses the foremost health threat globally. Diabetic nephropathy is the notable complication in diabetes, leading to end-stage renal disease (ESRD) and premature death. Abundant experimental evidence indicates that oxidative stress and inflammation are the important mediators in diabetic kidney diseases and interlinked with various signal transduction molecular mechanisms. Inflammasomes are the critical components of innate immunity and are recognized as a critical mediator of inflammation and autoimmune disorders. NOD-like receptor protein 3 (NLRP3) inflammasome is the well-characterized protein and it exhibits the sterile inflammation through the regulation of pro-inflammatory cytokines interleukin (IL)-1β and IL-18 production in tissues. In recent years, the role of NLRP3 inflammasome in the pathophysiology of diabetic kidney diseases in both clinical and experimental studies has generated great interest. In the current review, we focused on and discussed the role of NLRP3 inflammasome in diabetic nephropathy. A literature review was performed using online databases namely, PubMed, Scopus, Google Scholar and Web of science to explore the possible pharmacological interventions that blunt the NLRP3 inflammasome-caspase-1-IL-1β/IL-18 axis and shown to have a beneficial effect in diabetic kidney diseases. This review describes the inhibition of NLRP3 inflammasome activation as a promising therapeutic target for drug discovery in future.

Dipeptidyl Peptidase-4: A Potential Therapeutic Target in Diabetic Kidney Disease with SARS-CoV-2 Infection

Dipeptidyl peptidase-4 (DPP-4) is expressed ubiquitously in many tissues, including kidney, respiratory tract, and immune cells. Human DPP-4 has been identified as a functional receptor for the spike glycoprotein of the Middle East respiratory syndrome coronavirus. A large interface has been predicted in the docking of DPP-4/SARS-CoV-2 spike protein. Globally, 40% of diabetic patients develop diabetic kidney disease (DKD), a leading cause of end-stage renal disease. DPP-4 inhibitors possess anti-inflammatory properties which suggest their potential implication in DKD and SARS-CoV-2 immunopathogenesis.

Tacrolimus ameliorates tubulointerstitial inflammation in diabetic nephropathy via inhibiting the NFATc1/TRPC6 pathway

Tubulointerstitial inflammation is crucial for the progression of diabetic nephropathy (DN), and tubular cells act as a driving force in the inflammatory cascade. Emerging data suggested that tacrolimus (TAC) ameliorates podocyte injury and macrophage infiltration in streptozotocin (STZ) mice. However, the effect of TAC on tubulointerstitial inflammation remains unknown. We found that albuminuria and tubulointerstitial damage improved in db/db mice treated with TAC. Macrophage infiltration and expression of IL‐6, TNF‐α, fibronectin, collagen 1 and cleaved caspase 3 were inhibited as well. In addition, the expression of nuclear factor of activated T cell 1 (NFATc1) and transient receptor potential channel 6 (TRPC6) was up‐regulated in the kidneys of DN patients and correlated with tubular injury and inflammation. The expression of NFATc1 and TRPC6 also increased in the kidneys of db/db mice and HK‐2 cells with high glucose (HG), while TAC inhibited these effects. HG‐induced inflammatory markers and apoptosis were reversed by TAC and NFATc1 siRNA in HK‐2 cells, which was abolished by TRPC6 plasmid. Furthermore, HG‐induced TRPC6 expression was inhibited by NFATc1 siRNA, while NFATc1 nuclear translocation was inhibited by TAC, but was restored by TRPC6 plasmid in HK‐2 cells under HG conditions. These findings suggest that TAC ameliorates tubulointerstitial inflammation in DN through NFATc1/TRPC6 feedback loop.

Identification of C3 as a therapeutic target for diabetic nephropathy by bioinformatics analysis

The pathogenesis of diabetic nephropathy is not completely understood, and the effects of existing treatments are not satisfactory. Various public platforms already contain extensive data for deeper bioinformatics analysis. From the GSE30529 dataset based on diabetic nephropathy tubular samples, we identified 345 genes through differential expression analysis and weighted gene coexpression correlation network analysis. GO annotations mainly included neutrophil activation, regulation of immune effector process, positive regulation of cytokine production and neutrophil-mediated immunity. KEGG pathways mostly included phagosome, complement and coagulation cascades, cell adhesion molecules and the AGE-RAGE signalling pathway in diabetic complications. Additional datasets were analysed to understand the mechanisms of differential gene expression from an epigenetic perspective. Differentially expressed miRNAs were obtained to construct a miRNA-mRNA network from the miRNA profiles in the GSE57674 dataset. The miR-1237-3p/SH2B3, miR-1238-5p/ZNF652 and miR-766-3p/TGFBI axes may be involved in diabetic nephropathy. The methylation levels of the 345 genes were also tested based on the gene methylation profiles of the GSE121820 dataset. The top 20 hub genes in the PPI network were discerned using the CytoHubba tool. Correlation analysis with GFR showed that SYK, CXCL1, LYN, VWF, ANXA1, C3, HLA-E, RHOA, SERPING1, EGF and KNG1 may be involved in diabetic nephropathy. Eight small molecule compounds were identified as potential therapeutic drugs using Connectivity Map.

Pesticides-induced energy metabolic disorders

Metabolic disorders have become a heavy burden on society. Recently, through excessive use, pesticides have been found to be present in environmental matrixes and sometimes even accumulate in humans or other mammals through the food chain, which then causes health concerns. Evidence has indicated that pesticides have the potential to induce energy metabolic disorders by disturbing the physical process of energy absorption in the intestine and energy storage in the liver, adipose tissue and skeletal muscle in humans or other mammals. In addition, the homeostasis of energy regulation by the pancreas and immune cells is also affected by pesticides. These pesticide-induced disruptions ultimately cause abnormal levels of blood glucose and lipids, which in turn induce the development of related metabolic diseases, including overweight, underweight, insulin resistance and even diabetes. In this review, the results of previous studies focused on the induction of metabolic disorders by pesticides are summarized. We hope that this work will facilitate the discovery of a potential strategy for the treatment of diseases caused by pesticides.

Hirudin Protects Against Kidney Damage in Streptozotocin-Induced Diabetic Nephropathy Rats by Inhibiting Inflammation via P38 MAPK/NF-κB Pathway

Background

Inflammation-induced podocyte apoptosis plays an important role in kidney injury during diabetic nephropathy (DN). Hirudin (HIR), a natural compound extracted from leeches, can inhibit inflammation. However, whether HIR can protect the kidneys against inflammation during DN is unknown. In the present study, we aimed to study the effects of HIR on kidney damage in a DN rat model and explore its anti-inflammatory properties.

Methods

A streptozotocin-induced DN rat model was generated, and HIR was administered subcutaneously. Immortal podocytes and primary peritoneal macrophages were used for vitro studies. Hematoxylin and eosin staining was used to evaluate renal pathological changes; quantitative polymerase chain reaction and immunoblotting were used to detect gene expression; and TUNEL staining was used to detect apoptotic cells.

Results

Our results showed that HIR protected against renal injury, as indicated by kidney weight/body weight, serum creatinine, renal pathological changes, blood urea nitrogen, and detection of urine proteins. Notably, HIR treatment reduced macrophage infiltration, pro-inflammatory cytokine expression, and podocyte apoptosis in the kidney tissues of DN rats. In vitro, high glucose (HG) induced the activation of M1 macrophages, which was accompanied by increased podocyte apoptosis. HIR could decrease HG-induced podocyte apoptosis and suppress pro-inflammatory cytokine expression in podocytes in vitro. This was achieved via inhibition of p38 MAPK/NF-κB activation in renal tissues and podocytes.

Conclusion

HIR could inhibit inflammation via the p38 MAPK/NF-κB pathway, prevent podocyte apoptosis, and protect against kidney damage in a DN rat model.

Syzygium aromaticum Reduces Diabetes-induced Glucotoxicity via the NRF2/Glo1 Pathway

Advanced glycation end products and methylglyoxal are known to show increased levels in diabetic conditions and induce diverse metabolic disorders. However, the antiglycation ability of the bark of Syzygium aromaticum is not yet studied. In this study, we determined the inhibitory effects of S. aromaticum on AGE formation. Moreover, S. aromaticum showed breakage and inhibitory ability against the formation of AGE-collagen crosslinks. In SV40 MES13 cells, treatment with the S. aromaticum extract significantly ameliorated MG-induced oxidative stress as well as cytotoxicity. Furthermore, in the S. aromaticum extract-treated group, there was a reduction in levels of several diabetic markers, such as blood glucose, kidney weight, and urinary albumin to creatinine ratio in streptozotocin-induced diabetic rats. Treatment with the S. aromaticum extract significantly increased the expression of nuclear factor erythroid 2-related factor 2, a transcription factor involved in the expression of antioxidant enzymes. Moreover, the treatment significantly upregulated the expression of glyoxalase 1 and downregulated the expression of receptor for AGEs. These results suggest that the S. aromaticum extract might ameliorate diabetes-induced renal damage by inhibiting the AGE-induced glucotoxicity and oxidative stress through the Nrf2/Glo1 pathway.

Elevated First-Trimester Neutrophil Count Is Closely Associated With the Development of Maternal Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes

Chronic low-grade inflammation plays a central role in the pathophysiology of gestational diabetes mellitus (GDM). To investigate the ability of different inflammatory blood cell parameters in predicting the development of GDM and pregnancy outcomes, 258 women with GDM and 1,154 women without were included in this retrospective study. First-trimester neutrophil count outperformed white blood cell count and the neutrophil-to-lymphocyte ratio in the predictability for GDM. Subjects were grouped based on tertiles of neutrophil count during their first-trimester pregnancy. The results showed that as the neutrophil count increased, there was a stepwise increase in GDM incidence as well as in glucose and glycosylated hemoglobin levels, HOMA for insulin resistance (HOMA-IR), macrosomia incidence, and newborn weight. Neutrophil count was positively associated with prepregnancy BMI, HOMA-IR, and newborn weight. Additionally, neutrophil count was an independent risk factor for the development of GDM, regardless of the history of GDM. Spline regression showed that there was a significant linear association between GDM incidence and the continuous neutrophil count when it was >5.0 × 10⁹/L. This work suggested that the first-trimester neutrophil count is closely associated with the development of GDM and adverse pregnancy outcomes.

Effect of aerobic exercise on innate immune responses and inflammatory mediators in the spinal cord of diabetic rats

Neuronal inflammation is one of the pathophysiological causes of diabetes neuropathic pain. The purpose of this research was to determine the effect of aerobic exercise on innate immune responses and inflammatory mediators in the spinal dorsal horn in rats with diabetic neuropathic pain. 40 eight-week-old male Wistar rats (weight range 220±10.2 g) were randomly divided into four groups of (1) sedentary diabetic neuropathy (SDN), (2) training diabetic neuropathy (TDN), (3) training control (TC), and (4) sedentary control (SC). Diabetes was induced by injection of streptozocin (50 mg/kg). Following confirmation of behavioural tests for diabetes neuropathy, the training groups performed 6 weeks of moderate-intensity aerobic exercise on the treadmill. The expression of Toll like receptor (TLR)4, TLR2, tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-10 genes in L4-L6 spinal cord sensory neurons was measured by Real Time PCR. Two-way ANOVA and Bonferroni’s post hoc tests were used for statistical analysis. After performing aerobic exercise protocol, the TDN compared to the SDN showed a significant decrease in the mean score of pain in the formalin test and a significant increase in the latency in Tail-Flick test was observed. The expression of TLR4, TLR2, TNF-α and IL-1β genes was significantly higher in the SDN than in the SC group (P<0.05). The expression of the above genes in the TDN was significantly lower than the SDN group (P<0.05). Also, the expression level of IL-10 gene was significantly higher in the TDN than the SDN group (P<0.05). Aerobic exercise improved sensitivity of nociceptors to pain-inducing agents in diabetic neuropathy due to inhibition of inflammatory receptors and increased levels of anti-inflammatory agents in the nervous system. Thus, aerobic exercise should be used as a non-pharmacological intervention for diabetic patients to reduce neuropathic pain.

Implications of immunoglobulin G deposit in glomeruli in Chinese patients with diabetic nephropathy

BACKGROUND

In the current study, we explored the associations of glomerular immunoglobulin G (IgG) deposit and further investigated the pattern of IgG subclass deposition in the renal biopsy specimens from patients with diabetic nephropathy (DN).

METHODS

A total of 170 inpatients with type 2 diabetes mellitus and biopsy-proven DN who were followed up for at least 1 year were retrospectively recruited. Renal outcomes were defined by DN progression (end-stage renal disease [ESRD] or ≥ 50% reduction in estimated glomerular filtration rate [eGFR] from baseline). Additionally, 38 renal biopsy specimens of patients with renal IgG deposit underwent the immunofluorescence IgG1-4 staining.

RESULTS

The median follow-up period was 22 months. During follow-up, 38.23% (65) of patients progressed to ESRD, and 6.47% (11) of patients had an eGFR decline ≥50%. The multivariate Cox analysis demonstrated that the glomerular IgG deposit (hazard ratio, 1.835; 95% CI, 1.013-3.324, P = .045) was still significantly associated with DN progression when adjusted for the important clinical variables and pathological findings. In addition, a logistic regression showed that the glomerular IgG deposit was independently associated with glomerular basement membrane (GBM) thickness (odds ratio [OR], 1.276; 95% CI, 1.046-1.558; P = .016), Kimmelstiel-Wilson nodules formation (OR, 3.822; 95% CI, 1.052-13.881; P = .042), and C3 deposit in the glomeruli (OR, 124.883; 95% CI, 20.754-751.472; P < .001). The IgG subclass staining showed that IgG1 deposit along the GBM tended to be dominant (28/38) in IgG (+) patients with DN.

CONCLUSIONS

The glomerular IgG deposit affected glomerular structure and emerged as an independent risk factor for the renal clinical outcomes. In addition, IgG1 predominantly deposited along the GBM among the DN patients with IgG (+), which might be involved in the renal injury and progression of DN.

RIPK3 blockade attenuates tubulointerstitial fibrosis in a mouse model of diabetic nephropathy

Receptor-interacting protein kinase-3 (RIPK3) is a multifunctional regulator of cell death and inflammation. RIPK3 controls cellular signalling through the formation of the domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which is recognised to mediate renal fibrogenesis. The role of RIPK3 in diabetic kidney disease (DKD) induced renal fibrosis has not been previously determined. To define the action of RIPK3 in the development of diabetic kidney disease, wild-type (WT), RIPK3 -/- and endothelium-derived nitric oxide synthase (eNOS)-/- mice were induced to develop diabetes mellitus using multiple low doses of streptozotocin and maintained for 24 weeks. RIPK3 activity and NLRP3 expression were upregulated and fibrotic responses were increased in the kidney cortex of WT mice with established diabetic nephropathy compared to control mice. Consistently, mRNA expression of inflammasome components, as well as transforming growth factor beta 1 (TGFβ1), α smooth muscle actin (α-SMA) and collagen deposition were increased in diabetic kidneys of WT mice compared to control mice. However, these markers were normalised or significantly reversed in kidneys of diabetic RIPK3 -/- mice. Renoprotection was also observed using the RIPK3 inhibitor dabrafenib in eNOS-/- diabetic mice as demonstrated by reduced collagen deposition and myofibroblast activation. These results suggest that RIPK3 is associated with the development of renal fibrosis in DKD due to the activation of the NLRP3 inflammasome. Inhibition of RIPK3 results in renoprotection. Thus, RIPK3 may be a potential target for therapeutic intervention in patients with diabetic kidney disease.

The Mechanism of Contrast-Induced Acute Kidney Injury and Its Association with Diabetes Mellitus

Contrast-induced acute kidney injury (CI-AKI) is the third most common hospital-acquired AKI after AKI induced by renal perfusion insufficiency and nephrotoxic drugs, taking great adverse effects on the prognosis and increasing hospital stay and medical cost. Diabetes nephropathy (DN) is a common chronic complication of DM (diabetes mellitus), and DN is an independent risk factor for chronic kidney disease (CKD) and CI-AKI. The incidence of CI-AKI significantly increases in patients with renal injury, especially in DM-related nephropathy. The etiology of CI-AKI is not fully clear, and research studies on how DM becomes a facilitated factor of CI-AKI are limited. This review describes the mechanism from three aspects. ① Pathophysiological changes of CI-AKI in kidney under high-glucose status (HGS). HGS can enhance the oxidative stress and increase ROS which next causes stronger vessel constriction and insufficient oxygen supply in kidney via vasoactive substances. HGS also aggravates some ion pump load and the latter increases oxygen consumption. CI-AKI and HGS are mutually causal, making the kidney function continue to decline. ② Immunological changes of DM promoting CI-AKI. Some innate immune cells and pattern recognition receptors (PRRs) in DM and/or DN may respond to some damage-associated molecular patterns (DAMPs) formed by CI-AKI. These effects overlap with some pathophysiological changes in hyperglycemia. ③ Signaling pathways related to both CI-AKI and DM. These pathways involved in CI-AKI are closely associated with apoptosis, inflammation, and ROS production, and some studies suggest that these pathways may be potential targets for alleviating CI-AKI. In conclusion, the pathogenesis of CI-AKI and the mechanism of DM as a predisposing factor for CI-AKI, especially signaling pathways, need further investigation to provide new clinical approaches to prevent and treat CI-AKI.

Targeting NF-κB by the Cell-Permeable NEMO-Binding Domain Peptide Improves Albuminuria and Renal Lesions in an Experimental Model of Type 2 Diabetic Nephropathy

Diabetic nephropathy (DN) is a multifactorial disease characterized by hyperglycemia and close interaction of hemodynamic, metabolic and inflammatory factors. Nuclear factor-κB (NF-κB) is a principal matchmaker linking hyperglycemia and inflammation. The present work investigates the cell-permeable peptide containing the inhibitor of kappa B kinase γ (IKKγ)/NF-κB essential modulator (NEMO)-binding domain (NBD) as therapeutic option to modulate inflammation in a preclinical model of type 2 diabetes (T2D) with DN. Black and tan, brachyuric obese/obese mice were randomized into 4 interventions groups: Active NBD peptide (10 and 6 µg/g body weight); Inactive mutant peptide (10 µg/g); and vehicle control. In vivo/ex vivo fluorescence imaging revealed efficient delivery of NBD peptide, systemic biodistribution and selective renal metabolization. In vivo administration of active NBD peptide improved albuminuria (>40% reduction on average) and kidney damage, decreased podocyte loss and basement membrane thickness, and modulated the expression of proinflammatory and oxidative stress markers. In vitro, NBD blocked IKK-mediated NF-κB induction and target gene expression in mesangial cells exposed to diabetic-like milieu. These results constitute the first nephroprotective effect of NBD peptide in a T2D mouse model that recapitulates the kidney lesions observed in DN patients. Targeting IKK-dependent NF-κB activation could be a therapeutic strategy to combat kidney inflammation in DN.

Baicalin suppresses renal fibrosis through microRNA-124/TLR4/NF-κB axis in streptozotocin-induced diabetic nephropathy mice and high glucose-treated human proximal tubule epithelial cells

Renal fibrosis is a major pathological event in the development of diabetic nephropathy (DN). Baicalin is a flavonoid glycoside that possesses multiple pharmacological properties including anti-fibrotic activity. In the present study, the effects of baicalin on renal fibrosis along with related molecular basis were investigated in streptozotocin (STZ)-induced DN mouse model and high glucose (HG)-treated HK-2 human proximal tubule epithelial cell model. Renal injury was evaluated through blood urea nitrogen (BUN) and serum creatinine (Scr) levels and urine albumin creatine ratio (ACR). Renal fibrosis was assessed by type IV collagen (COLIV) and fibronectin (FN) protein expression and histopathologic analysis via Masson trichrome staining. Protein levels of COLIV, FN, NF-κB inhibitor alpha (IκBα), phosphorylated IκBα (p-IκBα), p65, phosphorylated p65 (p-p65), and toll-like receptor 4 (TLR4) were measured by western blot assay. MicroRNA-124 (miR-124) and TLR4 mRNA levels were detected by RT-qPCR assay. The interaction of miR-124 and TLR4 was examined by bioinformatics analysis, luciferase reporter assay, and RIP assay. Baicalin or miR-124 attenuated renal injury and fibrosis in STZ-induced DN mice. Baicalin inhibited the increase of COLIV and FN expression induced by HG through upregulating miR-124 in HK-2 cells. TLR4 was a target of miR-124. MiR-124 inhibited TLR4/NF-κB pathway activation and the inactivation of the NF-κB pathway hindered COLIV and FN expression in HG-stimulated HK-2 cells. Baicalin prevented renal fibrosis by increasing miR-124 and inactivating downstream TLR4/NF-κB pathway in DN, hinting the pivotal values of baicalin and miR-124 in the management of DN and renal fibrosis.

Pathogenic Pathways and Therapeutic Approaches Targeting Inflammation in Diabetic Nephropathy

Diabetic nephropathy (DN) is associated with an increased morbidity and mortality, resulting in elevated cost for public health systems. DN is the main cause of chronic kidney disease (CKD) and its incidence increases the number of patients that develop the end-stage renal disease (ESRD). There are growing epidemiological and preclinical evidence about the close relationship between inflammatory response and the occurrence and progression of DN. Several anti-inflammatory strategies targeting specific inflammatory mediators (cell adhesion molecules, chemokines and cytokines) and intracellular signaling pathways have shown beneficial effects in experimental models of DN, decreasing proteinuria and renal lesions. A number of inflammatory molecules have been shown useful to identify diabetic patients at high risk of developing renal complications. In this review, we focus on the key role of inflammation in the genesis and progression of DN, with a special interest in effector molecules and activated intracellular pathways leading to renal damage, as well as a comprehensive update of new therapeutic strategies targeting inflammation to prevent and/or retard renal injury.

Astragalus polysaccharides protect renal function and affect the TGF-/Smad signaling pathway in streptozotocin-induced diabetic rats

OBJECTIVES

The objective was to observe the effects of Astragalus polysaccharides on diabetes and on regulation of the TGF-β/Smad signaling pathway.

METHODS

A type 2 diabetic rat model was established with a high-fat diet in combination with low-dose streptozotocin (35 mg/kg). Astragalus polysaccharides were applied as treatment intervention and changes in blood glucose and kidney morphology and function were assessed.

RESULTS

Eight weeks after model establishment, kidney weight as a proportion of total weight (KW/TW) in the high-, medium-, and low-dose Astragalus polysaccharide groups was significantly lower than that in the model group, and the KW/TW value gradually decreased with increasing dose of polysaccharides in each treatment group. Fasting blood glucose in the low- and medium-dose Astragalus polysaccharide groups was numerically lower than that in the model group and fasting blood glucose in rats in the high-dose group was significantly lower than that in the model group. Levels of 24-hour urinary microalbumin, creatinine, blood urea nitrogen, collagens I, III, and IV, α-smooth muscle actin, transforming growth factor-β1, and Smad3 in Astragalus polysaccharide groups (all doses) were significantly lower than those in the model group.

CONCLUSIONS

Astragalus polysaccharide significantly improved blood glucose and protected kidney function in a rat diabetes model.

Enhanced myostatin expression and signalling promote tubulointerstitial inflammation in diabetic nephropathy

Myostatin (MSTN), a family member of the transforming growth factor (TGF)-β super family, has been detected in the tubuli of pig kidney, but its role in the human kidney is not known. In this study we observed upregulation of MSTN mRNA (~8 to 10-fold increase) both in the glomeruli and tubulointerstitium in diabetic nephropathy (DN). In DN, immunoreactive MSTN was mainly localized in the tubuli and interstitium (∼4-8 fold increase), where it colocalized in CD45+ cells. MSTN was also upregulated in the glomeruli and the arterial vessels. Tubulointerstitial MSTN expression was directly related to interstitial fibrosis (r = 0.54, p < 0.01). In HK-2 tubular epithelial cells, both high (30 mmol) glucose and glycated albumin upregulated MSTN mRNA and its protein (p < 0.05-0.01). MSTN-treated HK-2 cells underwent decreased proliferation, together with NF-kB activation and CCL-2 and SMAD 2,3 overexpression. In addition, MSTN induced intracellular ROS release and upregulated NADPH oxidase, effects which were mediated by ERK activation. In conclusion, our data show that MSTN is expressed in the human kidney and overexpressed in DN, mainly in the tubulointerstitial compartment. Our results also show that MSTN is a strong inducer of proximal tubule activation and suggest that MSTN overexpression contributes to kidney interstitial fibrosis in DN.

Roles of pattern recognition receptors in diabetic nephropathy

Diabetic nephropathy (DN) is currently the most common complication of diabetes. It is considered to be one of the leading causes of end-stage renal disease (ESRD) and affects many diabetic patients. The pathogenesis of DN is extremely complex and has not yet been clarified; however, in recent years, increasing evidence has shown the important role of innate immunity in DN pathogenesis. Pattern recognition receptors (PRRs) are important components of the innate immune system and have a significant impact on the occurrence and development of DN. In this review, we classify PRRs into secretory, endocytic, and signal transduction PRRs according to the relationship between the PRRs and subcellular compartments. PRRs can recognize related pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), thus triggering a series of inflammatory responses, promoting renal fibrosis, and finally causing renal impairment. In this review, we describe the proposed role of each type of PRRs in the development and progression of DN.

TLR4 Polymorphisms (896A>G and 1196C>T) Affect the Predisposition to Diabetic Nephropathy in Type 2 Diabetes Mellitus

PURPOSE

Type 2 diabetes mellitus (T2DM) is a disease with a steadily increasing incidence throughout the world. Some molecules regulating the innate immune responses such as toll-like receptor 4 (TLR4) have shown to be involved in late diabetic complications. This study aimed to investigate the association of TLR4 gene polymorphisms with clinicopathological aspects of T2DM in the Iranian population.

PATIENTS AND METHODS

Two TLR4 896A>G and 1196C>T polymorphisms were assessed in 100 T2DM patients and 100 healthy controls using sequence-specific primers PCR. Demographic, anthropometric, and biochemical parameters were obtained from the participants.

RESULTS

After logistic regression, in 1196C>T, a significant association was shown between diabetic nephropathy (DN) and CT genotype (P= 0.04, OR= 4.35, CI= (1.04-18.1)). TG level has increased significantly in both T2DM and control subjects with CT genotype (P= 0.027, OR= 1.005, 95% CI= (1.001-1.01)). For 896A>G variant, a significant association was also detected between AG genotype and increased oral glucose tolerance test (OGTT) level (P= 0.048, OR= 1.003, 95% CI= (1.00-1.005)).

CONCLUSION

Although minor alleles of 1196C>T and 896A>G variants have not directly been associated with type 2 diabetes, by involving in the dysregulation of serum TG and blood sugar levels, they might increase the risk of DN.

Caspase-3 Promotes Diabetic Kidney Disease Through Gasdermin E-Mediated Progression to Secondary Necrosis During Apoptosis

BACKGROUND

Apoptosis has been repeatedly linked with diabetic kidney disease (DKD), which is a programmed cell death mediated by effector caspases-3, 6 and 7, targeting >600 substrates. However, the pathophysiologic correlations of this process remain obscure. As a putative tumor suppressor, gasdermin E (GSDME) was recently reported to be cleaved by caspase-3 to produce a GSDME-N fragment which targets the plasma membrane to switch apoptosis to secondary necrosis. However, it remains elusive whether GSDME is involved in the regulation of DKD.

METHODS

To evaluate the therapeutic potential of caspase-3 inhibition in DKD, we administered caspase-3 inhibitor Z-DEVD-FMK to STZ-induced diabetic mice for eight weeks. Albuminuria, renal function, pathological changes, and indicators of secondary necrosis and fibrosis were evaluated. In vitro, human tubule epithelial cells (HK-2 cells) were subjected to high-glucose treatment. Secondary necrosis was determined by LDH release, GSDME cleavage, and morphological feature under confocal microscopy. Z-DEVD-FMK and GSDME inhibition by shRNA were administered to suppress the cleavage and expression of GSDME. Flow cytometry, cytotoxicity assay and immunoblot were used to assess cell death and fibrogenesis.

RESULTS

Caspase-3 inhibition by Z-DEVD-FMK ameliorated albuminuria, renal function, and tubulointerstitial fibrosis in diabetic mice. The nephroprotection mediated by Z-DEVD-FMK was potentially associated with inhibition of GSDME. In vitro, molecular and morphological features of secondary necrosis were observed in glucose-stressed HK-2 cells, evidenced by active GSDME cleavage, ballooning of the cell membrane, and release of cellular contents. Here we showed that caspase-3 inhibition prevented GSDME activation and cell death in glucose-treated tubular cells. Specifically, knocking down GSDME directly inhibited secondary necrosis and fibrogenesis.

CONCLUSION

These data suggest GSDME-dependent secondary necrosis plays a crucial role in renal injury, and provides a new insight into the pathogenesis of DKD and a promising target for its treatment.

Emerging Roles for NLRC5 in Immune Diseases

Innate immunity activates the corresponding immune response relying on multiple pattern recognition receptors (PRRs) that includes pattern recognition receptors (PRRs), like NOD-like receptors (NLRs), RIG-I-like receptors (RLRs), and C-type lectin receptors (CLRs), which could accurately recognize invasive pathogens. In particular, NLRs belong to a large protein family of pattern recognition receptors in the cytoplasm, where they are highly correlated with activation of inflammatory response system followed by rapid clearance of invasive pathogens. Among the NLRs family, NLRC5, also known as NOD4 or NOD27, accounts for a large proportion and involves in immune responses far and wide. Notably, in the above response case of inflammation, the expression of NLRC5 remarkably increased in immune cells and immune-related tissues. However, the evidence for higher expression of NLRC5 in immune disease still remains controversial. It is noted that the growing evidence further accounts for the participation of NLRC5 in the innate immune response and inflammatory diseases. Moreover, NLRC5 has also been confirmed to exert a critical role in the control of regulatory diverse signaling pathways. Together with its broad participation in the occurrence and development of immune diseases, NLRC5 can be consequently treated as a potential therapeutic target. Nevertheless, the paucity of absolute understanding of intrinsic characteristics and underlying mechanisms of NLRC5 still make it hard to develop targeting drugs. Therefore, current summary about NLRC5 information is indispensable. Herein, current knowledge of NLRC5 is summarized, and research advances in terms of NLRC5 in characteristics, biological function, and regulatory mechanisms are reviewed.

Deficiency of C3a receptor attenuates the development of diabetic nephropathy

Objective

Diabetic nephropathy (DN) is the leading cause of chronic kidney disease and end-stage renal disease. Emerging evidence suggests that complement activation is involved in the pathogenesis of DN. The aim of this study was to investigate the pathogenic role of C3a and C3a receptor (C3aR) in DN.

Research design and methods

The expression of C3aR was examined in the renal specimen of patients with DN. Using a C3aR gene knockout mice (C3aR-/-), we evaluated kidney injury in diabetic mice. The mouse gene expression microarray was performed to further explore the pathogenic role of C3aR. Then the underlying mechanism was investigated in vitro with macrophage treated with C3a.

Results

Compared with normal controls, the renal expression of C3aR was significantly increased in patients with DN. C3aR-/- diabetic mice developed less severe diabetic renal damage compared with wild-type (WT) diabetic mice, exhibiting significantly lower level of albuminuria and milder renal pathological injury. Microarray profiling uncovered significantly suppressed inflammatory responses and T-cell adaptive immunity in C3aR-/- diabetic mice compared with WT diabetic mice, and this result was further verified by immunohistochemical staining of renal CD4+, CD8+ T cells and macrophage infiltration. In vitro study demonstrated C3a can enhance macrophage-secreted cytokines which could induce inflammatory responses and differentiation of T-cell lineage.

Conclusions

C3aR deficiency could attenuate diabetic renal damage through suppressing inflammatory responses and T-cell adaptive immunity, possibly by influencing macrophage-secreted cytokines. Thus, C3aR may be a promising therapeutic target for DN.

Mitochondrial Damage and Activation of the STING Pathway Lead to Renal Inflammation and Fibrosis

Fibrosis is the final common pathway leading to end-stage renal failure. By analyzing the kidneys of patients and animal models with fibrosis, we observed a significant mitochondrial defect, including the loss of the mitochondrial transcription factor A (TFAM) in kidney tubule cells. Here, we generated mice with tubule-specific deletion of TFAM (Ksp-Cre/Tfamflox/flox). While these mice developed severe mitochondrial loss and energetic deficit by 6 weeks of age, kidney fibrosis, immune cell infiltration, and progressive azotemia causing death were only observed around 12 weeks of age. In renal cells of TFAM KO (knockout) mice, aberrant packaging of the mitochondrial DNA (mtDNA) resulted in its cytosolic translocation, activation of the cytosolic cGAS-stimulator of interferon genes (STING) DNA sensing pathway, and thus cytokine expression and immune cell recruitment. Ablation of STING ameliorated kidney fibrosis in mouse models of chronic kidney disease, demonstrating how TFAM sequesters mtDNA to limit the inflammation leading to fibrosis.

Pattern Recognition Receptor-Mediated Chronic Inflammation in the Development and Progression of Obesity-Related Metabolic Diseases

Obesity-induced chronic inflammation is known to promote the development of many metabolic diseases, especially insulin resistance, type 2 diabetes mellitus, nonalcoholic fatty liver disease, and atherosclerosis. Pattern recognition receptor-mediated inflammation is an important determinant for the initiation and progression of these metabolic diseases. Here, we review the major features of the current understanding with respect to obesity-related chronic inflammation in metabolic tissues, focus on Toll-like receptors and nucleotide-binding oligomerization domain-like receptors with an emphasis on how these receptors determine metabolic disease progression, and provide a summary on the development and progress of PRR antagonists for therapeutic intervention.

Therapeutic potential of NaoXinTong Capsule on the developed diabetic nephropathy in db/db mice

The current treatment for diabetic nephropathy (DN) is still limited. NaoXinTong Capsule (NXT) is a Chinese Medicine prescribed to patients with cardiovascular disease. It can also ameliorate metabolic syndromes in patients indicating its anti-diabetic properties. Herein we report the therapeutic effects of NXT on the developed DN. The db/db diabetic mice at ˜12 weeks old, the age with DN at middle/advanced stages, were treated with NXT for 12 weeks. We found NXT treatment reduced diabetes-induced hyperglycemia and dyslipidemia, thereby substantially reduced DN progress. In the kidney, NXT reduced mesangial matrix expansion and glomerulosclerosis by inhibiting extracellular matrix accumulation through activation of matrix metalloproteinase 2/9 and inactivating transforming growth factor β1 expression. NXT reduced podocyte injury by reducing renal inflammation and expression of adhesion molecules. Mechanically, NXT potently activated AMPKα in multiple tissues thereby enhancing energy metabolism. In the liver, NXT increased glucokinase expression and insulin sensitivity by increasing insulin receptor substrate 1/2 and protein kinase B (AKT) 1/2 expression/phosphorylation. In skeletal muscle, NXT activated expression of glucose transporter type 4, AKT, glycogen synthase and peroxisome proliferator activated receptor α/γ. In adipose tissue, NXT reduced fatty acid synthase while activating hormone-sensitive lipase expression. Taken together, our study demonstrates that NXT reduced progress of the developed DN by ameliorating glucose, lipid and energy metabolism, maintaining renal structural and functional integrity. Our study also indicates the potential application of NXT for DN treatment in clinics.

Sodium butyrate alleviates high-glucose-induced renal glomerular endothelial cells damage via inhibiting pyroptosis

We recently found that Sodium butyrate (NaB) possesses anti-inflammatory effects in diabetic nephropathy (DN) mouse model and in high-glucose induced mouse glomerular mesangial cells. Pyroptosis is a programmed cell death accompanied with the release of pro-inflammatory factors. Gasdermin D (GSDMD) is a novel discovered pivotal executive protein of pyroptosis, which can be cleaved by inflammatory caspases. The aim of our study is to verify if NaB have some effects against high-glucose induces pyroptosis in renal Glomerular endothelial cells (GECs). For this aim, human GECs were cultured and exposed to high-glucose. Exogenous NaB, caspase 1 inhibitor Ac-YVAD-CMK (A-Y-C) or knockdown GSDMD by siRNA were used. We found high glucose could increase Propidium Iodide (PI) positive cells and elevate release of lactate dehydrogenase (LDH), Interleukin 1 beta (IL-1β) and Interleukin 18 (IL-18); protein levels of GSDMD, GSDMD N-terminal domain (GSDMD-N) and cleaved-caspase-1 were also elevated. Effect of NaB on LDH release and PI positive cells was further enhanced by inhibiting caspase 1-GSDMD. In addition, high glucose-induced nuclear factor kappa-B (NF-κB)/NF-κB inhibitor α (IκB-α) signaling pathway was reversed by NaB or A-Y-C administration. In conclusion, NaB could ameliorate high-glucose induced GECs via caspase1-GSDMD canonical pyroptosis pathway; and NF-κB/IκB-α signaling pathway was involved in it.

CKD in diabetes: diabetic kidney disease versus nondiabetic kidney disease

The increasing global prevalence of type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) has prompted research efforts to tackle the growing epidemic of diabetic kidney disease (DKD; also known as diabetic nephropathy). The limited success of much of this research might in part be due to the fact that not all patients diagnosed with DKD have renal dysfunction as a consequence of their diabetes mellitus. Patients who present with CKD and diabetes mellitus (type 1 or type 2) can have true DKD (wherein CKD is a direct consequence of their diabetes status), nondiabetic kidney disease (NDKD) coincident with diabetes mellitus, or a combination of both DKD and NDKD. Preclinical studies using models that more accurately mimic these three entities might improve the ability of animal models to predict clinical trial outcomes. Moreover, improved insights into the pathomechanisms that are shared by these entities - including sodium-glucose cotransporter 2 (SGLT2) and renin-angiotensin system-driven glomerular hyperfiltration and tubular hyper-reabsorption - as well as those that are unique to individual entities might lead to the identification of new treatment targets. Acknowledging that the clinical entity of CKD plus diabetes mellitus encompasses NDKD as well as DKD could help solve some of the urgent unmet medical needs of patients affected by these conditions.

Roles of Inflammasomes in Inflammatory Kidney Diseases

The immune system has a central role in eliminating detrimental factors, by frequently launching inflammatory responses towards pathogen infection and inner danger signal outbreak. Acute and chronic inflammatory responses are critical determinants for consequences of kidney diseases, in which inflammasomes were inevitably involved. Inflammasomes are closely linked to many kidney diseases such as acute kidney injury and chronic kidney diseases. Inflammasomes are macromolecules consisting of multiple proteins, and their formation initiates the cleavage of procaspase-1, resulting in the activation of gasdermin D as well as the maturation and release of interleukin-1β and IL-18, leading to pyroptosis. Here, we discuss the mechanism in which inflammasomes occur, as well as their roles in inflammatory kidney diseases, in order to shed light for discovering new therapeutical targets for the prevention and treatment of inflammatory kidney diseases and consequent end-stage renal disease.

Diabetic Foot Syndrome in the Twenty-First Century

Diabetes mellitus is an international epidemic. In the United States, the prevalence of diabetes has increased from estimates in 1990 when 6.5% of the population was affected and 6.2 million people had diabetes compared with the estimates in 2017 with 24.7 million people with diabetes or accounting 9.6% of the adult population. The diabetic foot syndrome manifests as a combination of diabetes-related diseases including diabetic sensory neuropathy, limited joint mobility, immunopathy, peripheral arterial disease, foot ulceration, and Charcot arthropathy. The culmination of these provides an ideal environment for unrecognized tissue injury that leads to ulceration, infection, infection, and amputation.

A Clinical Review of Diabetic Foot Infections

"Diabetic foot infections (DFIs) are a common cause of morbidity and mortality. This article summarizes current knowledge regarding DFI epidemiology, disease pathogenesis, and the impact of antimicrobial resistance among DFI. An evidence-based approach to clinical assessment, diagnosing osteomyelitis, as well as medical and surgical treatment is discussed, including a review of empiric and directed antibiotic treatment recommendations. The current state and needs of the clinical literature are identified throughout, with a discussion of the supporting role of infectious diseases specialists as well as future directions of the field."