Genetic variations in key inflammatory cytokines exacerbates the risk of diabetic nephropathy by influencing the gene expression

Investigations of associations between TNF-α promoter polymorphisms and genetic susceptibility to type 2 diabetes mellitus: A cross-sectional study in Chinese Han population

Type 2 diabetes (T2DM) is characterised by insulin resistance and a relative shortage of insulin secretion. Tumour necrosis factor-α (TNF-α) plays an important role in insulin resistance by impairing insulin signal transduction. The variants of the TNF-α promoter region are considered to influence its transcription and are associated with the TNF-α level. Therefore, it is worth detecting the association of the variants in the TNF-α gene with the development of T2DM. The aim of this study was to investigate the association of five variants (rs1799964, rs1800630, rs1799724, rs1800629 and rs361525) in the TNF-α gene promoter region with T2DM in a Chinese Han population. A total of 713 subjects with T2DM and 751 nondiabetic subjects were genotyped using the TaqMan method. The associations of the five variants with the development of T2DM were evaluated. The associations of the five variant genotypes with metabolic traits in nondiabetic subjects were analysed. Our data showed that the A allele of rs1800629 could increase the risk of developing T2DM (p = .002, OR = 1.563; 95% CI: 1.18-2.08). According to inheritance mode analysis, compared with the G/G genotype, the G/A+2A/A genotype of rs1800629 showed a risk effect on T2DM in the log-additive mode (p = .002, OR = 1.56; 95% CI: 1.17-2.07). The haplotypes analysis identified that the rs1799724-rs1800629CA was associated with high risk of the development of T2DM (p = .002, OR = 1.559, 95% CI: 1.173-2.072). Conversely, the rs1799724-rs1800629CG was a protective haplotype of T2DM (p = .001, OR = 0.732, 95% CI: 0.607-0.884). Moreover, compared with the rs1799964 (T/T+C/T) genotype, the rs1799964 C/C genotype was associated with higher glycosylated haemoglobin (HbA1c) levels in nondiabetic subjects (p = .017). Our results revealed that the rs1800629 in the TNF-α gene promoter region was associated with T2DM in a Chinese Han population.

Nanopore-based full-length transcriptome sequencing for understanding the underlying molecular mechanisms of rapid and slow progression of diabetes nephropathy

BACKGROUND

Diabetic nephropathy (DN) has been a major factor in the outbreak of end-stage renal disease for decades. As the underlying mechanisms of DN development remains unclear, there is no ideal methods for the diagnosis and therapy.

OBJECTIVE

We aimed to explore the key genes and pathways that affect the rate progression of DN.

METHODS

Nanopore-based full-length transcriptome sequencing was performed with serum samples from DN patients with slow progression (DNSP, n = 5) and rapid progression (DNRP, n = 6).

RESULTS

Here, transcriptome proclaimed 22,682 novel transcripts and obtained 45,808 simple sequence repeats, 1,815 transcription factors, 5,993 complete open reading frames, and 1,050 novel lncRNA from the novel transcripts. Moreover, a total of 341 differentially expressed transcripts (DETs) and 456 differentially expressed genes (DEGs) between the DNSP and DNRP groups were identified. Functional analyses showed that DETs mainly involved in ferroptosis-related pathways such as oxidative phosphorylation, iron ion binding, and mitophagy. Moreover, Functional analyses revealed that DEGs mainly involved in oxidative phosphorylation, lipid metabolism, ferroptosis, autophagy/mitophagy, apoptosis/necroptosis pathway.

CONCLUSION

Collectively, our study provided a full-length transcriptome data source for the future DN research, and facilitate a deeper understanding of the molecular mechanisms underlying the differences in fast and slow progression of DN.

Associations between the polymorphisms of main components in PI3K/Akt pathway and risk of diabetic kidney disease: A meta-analysis

AIMS

Diabetic kidney disease (DKD) is a severe microvascular complication frequently associated with type 1 and type 2 diabetes mellitus. The objective of this work was to evaluate the relevance of PI3K/Akt pathway polymorphisms and DKD susceptibility by a meta-analysis.

METHODS

Case-control studies related to the relationship between PI3K/Akt pathway polymorphisms and DKD risk were searched from Pubmed, Embase, Cochrane Library, SINOMED, CNKI, and Wanfang databases. Statistical analysis and heterogeneity test were conducted by Review Manager 5.4.

RESULTS

Totally, 52 eligible studies were enrolled, including seven single nucleotide polymorphisms (SNPs) for four genes in the PI3K/AKT pathway (GNB3: rs5443; eNOS: rs1799983, rs869109213, rs2070744; IL-6: rs1800795, rs1800796; TNFα: rs1800629). The "M" allele of eNOS rs1799983 was related to the increased risk of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 75%, OR = 1.29, 95%CI 1.07-1.56; MM + WM vs. WW: I2  = 75%, OR = 1.50, 95%CI 1.21-1.86). The "M" allele of eNOS rs869109213 was implicated with higher prevalence of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 63%, OR = 1.43, 95%CI 1.22-1.68; MM + WM vs. WW: I2  = 50%, OR = 1.36, 95%CI 1.16-1.58; MM vs. WM + WW: I2  = 59%, OR = 2.20, 95%CI 1.41-3.43). The "M" allele of eNOS rs2070744 was implicated with higher prevalence of DKD under random effects model, especially in Indian population (Overall: M vs. W: I2  = 47%, OR = 1.35, 95%CI 1.15-1.59; MM + WM vs. WW: I2  = 45%, OR = 1.32, 95%CI 1.07-1.62; MM vs. WM + WW: I2  = 65%, OR = 2.29, 95%CI 1.39-3.77). The "M" allele of IL-6 rs1800796 was predominately associated with higher DKD risks under random effects model, especially in Asian population (Overall: M versus W: I2  = 23%, OR = 1.49, 95%CI 1.21-1.84; MM + WM vs. WW: I2  = 1%, OR = 1.43, 95%CI 1.15-1.77; MM + WM vs. WW: I2  = 71%, OR = 2.77, 95%CI 1.09-7.06).

CONCLUSIONS

This meta-analysis indicated that polymorphisms in the PI3K/Akt pathway in eNOS rs1799983, rs869109213, rs2070744, and IL-6 rs1800796 were related to the increased risk of DKD.

Oregano as a potential source of antidiabetic agents

Oregano is the name given to a great variety of herbs belonging mainly to the Lamiaceae and Verbenaceae botanical families. Oregano species are rich sources of phytochemicals such as phenolic compounds like rosmarinic acid, salvianolic acid, and luteolin, among others. A few articles have previously accessed some potential pharmacological bioactivities of oregano plants; however, none has focused on the antidiabetic studies. This review aims to summarize recent studies about the potential effect of phenolic compounds from oregano plant species. The reports were retrieved from electronic databases such as PubMed, Web of Science, National Center for Biotechnology Information (NCBI), and Scopus. In addition, articles related to the mentioned topics and published between 2004-2022 were selected. The results from this study show that the antidiabetic pharmacological reports of oregano phenolic compounds are mainly in vitro reports. Therefore, the diversity of oregano species yields a broad variety of phenolic constituents, where preclinical and clinical studies are strongly recommended.

IL-6 gene rs1800795 polymorphism and diabetes mellitus: a comprehensive analysis involving 42,150 participants from a meta-analysis

BACKGROUND

Over the past two decades, several studies have focused on the association between a common polymorphism (rs1800795) from interleukin-6 (IL-6) gene and Diabetes Mellitus (DM) risk. However, the results remain ambiguous and indefinite.

METHODS

A comprehensive analysis was performed to explore this relationship. A search was conducted in the PubMed, Embase, Chinese (CNKI and Wanfang), and GWAS Catalog databases, covering all publications until February 10, 2022. Odds ratios (OR) with 95% confidence intervals (CI) were used to evaluate the strength of the association. Publication bias was assessed using both Begg and Egger tests.

RESULTS

Overall, 34 case-control studies with 7257 T2DM patients and 15,598 controls, and 12 case-control studies (10,264 T1DM patients and 9031 health controls) were included in the analysis. A significantly lower association was observed between the rs1800795 polymorphism and T2DM risk in Asians, mixed population, and hospital-based (HB) subgroups (C-allele vs. G-allele: OR = 0.76, 95% CI  0.58-0.99, P = 0.039 for Asians; CG vs. GG: OR = 0.74, 95% CI  0.58-0.94, P = 0.014 for mixed population; CC vs. GG: OR = 0.61, 95% CI  0.41-0.90, P = 0.014 for HB). However, increased associations were found from total, mixed population, and HB subgroups between rs1800795 polymorphism and T1DM susceptibility (CG vs. GG: OR = 1.32, 95% CI 1.01-1.74, P = 0.043 for total population, CC vs. GG: OR = 2.45, 95% CI 1.18-5.07, P = 0.016 for mixed individuals; C-allele vs. G-allele: OR = 1.29, 95% CI 1.07-1.56, P = 0.0009 for HB subgroup).

CONCLUSIONS

In summary, there is definite evidence to confirm that IL-6 rs1800795 polymorphism is associated with susceptibility to decreased T2DM and increased T1DM.

The Effect of Oral Magnesium Supplementation on Inflammatory Biomarkers in Adults: A Comprehensive Systematic Review and Dose-response Meta-analysis of Randomized Clinical Trials

This is a comprehensive systematic review and dose-response meta-analysis evaluating the effects of oral magnesium supplementation on inflammatory biomarkers including C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) among adults. The major databases including PubMed, Web of Science, Embase, and Google Scholar were searched for relevant publications until December 14, 2020, using appropriate keywords. The Cochrane Collaboration tool was used to assess the quality of each study. We also performed a subgroup analysis to identify probable sources of heterogeneity. A total of 18 studies with 927 participants fulfilled the eligibility criteria and included in this meta-analysis. Our results indicate that the supplementation with magnesium had no statistically significant effect on serum concentrations of CRP (WMD, - 0.49; 95% CI, - 1.72 to 0.75 mg/L; P = 0.44), IL-6 (WMD, - 0.03; 95% CI, - 0.40 to 0.33 pg/mL; P = 0.86), and TNF-α (WMD, 0.12; 95% CI, - 0.08 to 0.31 pg/mL; P = 0.24) compared with controls. In addition, based on dose-response assessment, no significant non-linear association was found between magnesium supplementation dosage or duration on serum CRP and IL-6 concentrations. The findings of the present systematic review and meta-analysis did not support the notion that oral magnesium supplementation could have favorable effects on CRP, IL-6, and TNF-α in the adult population.

Long Noncoding RNA ENSG00000254693 Promotes Diabetic Kidney Disease via Interacting with HuR

Diabetic kidney disease (DKD) is one of the most common complications of diabetes mellitus (DM), without suitable therapies, causing end-stage renal diseases (ESRDs) ultimately. Moreover, there is increasing evidence demonstrating that long noncoding RNAs (lncRNAs) play crucial roles in the development of DKD. Our RNA sequencing data revealed a large group of differentially expressed lncRNAs in renal tissues of DKD, of which lncRNA ENSG00000254693 (lncRNA 254693 for short) changed drastically. In this study, we found that the expression of lncRNA 254693 was increased in both DKD patients and high-glucose-induced human podocytes. 5'/3'RACE and Northern blot assays were used to find the full length of lncRNA ENSG00000254693 which is 558 nucleotides and nonisoform that existed in human podocyte. Downregulation of lncRNA 254693 remarkably reversed the elevation of inflammation, apoptosis, and podocyte injury caused by high glucose. Then, we did bioinformatics analysis via RBPDB and found that lncRNA 254693 can combine with HuR, a RNA binding protein. Meanwhile, immunofluorescence and in situ hybridization double staining was used to prove the existence of colocalization between them. Intriguingly, lncRNA 254693 knockdown decreased HuR levels, while HuR knockdown also decreased the level of lncRNA 254693 and its stability. After this, RNA immunoprecipitation assay results confirmed the binding association between them again. In addition, we found that HuR was increased in high glucose-induced podocytes, and the silence of HuR could alleviate podocyte injury, inflammation, and apoptosis. These results together suggested a novel feedback regulation between lncRNA 254693 and HuR which could involve in podocyte injury and may serve as a predicted target for DKD therapies.

Association between polymorphisms of cytokine genes and diabetic nephropathy: A comprehensive systematic review and meta-analysis

AIM

Diabetic nephropathy (DN) is one of the microvascular complications of diabetes, leading to renal failure. In this study, we sought to systematically investigate the cytokine gene polymorphisms association with DN.

METHODS

A structured bibliographic search on PubMed, Scopus, and EMBASE databases has been performed to identify related papers. The odds ratio and corresponding 95% confidence intervals (CIs) were calculated to estimate the association.

RESULTS

Overall, the pooled results showed that the dominant models of TNF-α rs1800629, IL-1β rs16944, IL-8 rs4073, and IL-10 rs1800896 were associated with increased susceptibility to DN. Also, the pooled analyses of the mutant allele vs wild allele of TNF-α rs1800629, rs1799964, IL-1β rs16944, and IL-8 rs4073 were associated with increased susceptibility to DN. Rs1800629, rs16944, rs4073, and rs1800896 polymorphisms were significantly associated with DN susceptibility, suggesting its potential use as a genetic risk marker in the population.

miR-23a-3p regulates the inflammatory response and fibrosis in diabetic kidney disease by targeting early growth response 1

Diabetic kidney disease (DKD) has become the most common cause of chronic kidney disease. Proteinuria is generally considered one of the clinical indicators of renal damage, and it is also closely related to the progression of DKD. Accumulating evidence indicates that proteinuria induces an upregulation of the expression levels of inflammatory cytokines and fibrosis markers in renal tubular epithelial cells, but the mechanism remains unclear. Previously, we showed that early growth response 1 (Egr1) played a key role in renal tubular injury. However, the upstream mechanism of Egr1 in the development of DKD is poorly understood. In this study, we found that albumin stimulation significantly increased the expression levels of Egr1, interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), and fibronectin (FN) in HK-2 cells but decreased miR-23a-3p levels. We then identified that miR-23a-3p targeted the 3′ untranslated region (UTR) of Egr1 and directly suppressed the expression of Egr1. Moreover, we found that overexpression and inhibition of miR-23a-3p in HK-2 cells attenuated and promoted the expression of IL-6, TNF-α, and FN, respectively. Additionally, Egr1 silencing reversed the inflammation and fibrosis caused by the miR-23a-3p inhibitor. Thus, we conclude that miR-23a-3p attenuates the development of DKD through Egr1, suggesting that targeting miR-23a-3p may be a novel therapeutic approach for DKD.

Genetic associated complications of type 2 Diabetes Mellitus: a review

According to the International Diabetes Federation, the number of adults (age of 20-79) being diagnosed with Diabetes Mellitus (DM) have increased from 285 million in year 2009 to 463 million in year 2019 which comprises of 95% Type 2 DM patient (T2DM). Research have claimed that genetic predisposition could be one of the factors causing T2DM complications. In addition, T2DMcomplications cause an incremental risk to mortality. Therefore, this article aims to discuss some complications of T2DM in and their genetic association. The complications that are discussed in this article are diabetic nephropathy, diabetes induced cardiovascular disease, diabetic neuropathy, Diabetic Foot Ulcer (DFU) and Alzheimer's disease. According to the information obtained, genes associated with diabetic nephropathy (DN) are gene GABRR1 and ELMO1 that cause injury to glomerular. Replication of genes FRMD3, CARS and MYO16/IRS2 shown to have link with DN. The increase of gene THBS2, NGAL, PIP, TRAF6 polymorphism, ICAM-1 encoded for rs5498 polymorphism and C667T increase susceptibility towards DN in T2DM patient. Genes associated with cardiovascular diseases are Adiponectin gene (ACRP30) and Apolipoprotein E (APOE) polymorphism gene with ξ2 allele. Haptoglobin (Hp) 1-1 genotype and Mitochondria Superoxide Dismutase 2 (SOD2) plays a role in cardiovascular events. As for genes related to diabetic neuropathy, Janus Kinase (JAK), mutation of SCN9A and TRPA1 gene and destruction of miRNA contribute to pathogenesis of diabetic neuropathy among T2DM patients. Expression of cytokine IL-6, IL-10, miR-146a are found to cause diabetic neuropathy. Besides, A1a16Va1 gene polymorphism, an oxidative stress influence was found as one of the gene factors. Diabetic retinopathy (DR) is believed to have association with Monocyte Chemoattractant Protein-1 (MCP-1) and Insulin-like Growth Factor 1 (IGF1). Over-expression of gene ENPP1, IL-6 pro-inflammatory cytokine, ARHGAP22's protein rs3844492 polymorphism and TLR4 heterozygous genotype are contributing to significant pathophysiological process causing DR, while research found increases level of UCP1 gene protects retina cells from oxidative stress. Diabetic Foot Ulcer (DFU) is manifested by slowing in reepithelialisation of keratinocyte, persistence wound inflammation and healing impairment. Reepithelialisation disturbance was caused by E2F3 gene, reduction of Tacl gene encoded substance P causing persistence inflammation while expression of MMp-9 polymorphism contributes to healing impairment. A decrease in HIF-1a gene expression leads to increased risk of pathogenesis, while downregulation of TLR2 increases severity of wound in DFU patients. SNPs alleles has been shown to have significant association between the genetic dispositions of T2DM and Alzheimer's disease (AD). The progression of AD can be due to the change in DNA methylation of CLOCK gene, followed with worsening of AD by APOE4 gene due to dyslipidaemia condition in T2DM patients. Insulin resistance is also a factor that contributes to pathogenesis of AD.

Acetate ameliorates nephrotoxicity in streptozotocin-nicotinamide-induced diabetic rats: Involvement of xanthine oxidase activity

Impaired renal function is a common complication of diabetes mellitus (DM) that often degenerates to cardiovascular disease, contributing to high morbidity and reduced survival worldwide. Short chain fatty acids (SCFAs), including acetate has shown potential benefits in glycemic or metabolic regulation but its effect on diabetes-associated renal toxicity/impairment is not clear. Herein, we investigated the hypothesis that acetate would ameliorate renal toxicity, accompanying DM, possibly by suppression of xanthine oxidase (XO) activity. Adult male Wistar rats (230-260 g) were allotted into groups (n = 6/group) namely: control (vehicle; po), sodium acetate (NaAc)-treated (200 mg/kg), diabetic with or without NaAc groups. DM was induced by intraperitoneal injection of streptozotocin 65 mg/kg after a dose of nicotinamide (110 mg/kg). Diabetic animals showed increased fasting glucose and insulin, renal triglyceride, total cholesterol, atherogenic lipid, malondialdehyde, XO, tissue necrosis factor-α, uric acid, interleukin-6, aspartate transaminase/alanine aminotransferase ratio, gamma-glutamyl transferase and decreased glutathione and nitric oxide concentration. The renal tissue was characterized with disrupted tissue architecture, enlarged Bowman's space, congested glomeruli and adherence of abnormal segments of tuft to Bowman's capsule with consequent elevated serum creatinine and urea concentration. However, these alterations were attenuated by NaAc. The study demonstrates that acetate ameliorates diabetes-induced nephrotoxicity, which is associated with suppressed XO and its accompanied pro-inflammatory mediators. Therefore, SCFAs, acetate would be a promising dietary-derived therapeutic agent for the prevention and management of diabetes-associated renal disturbances.

Macrophage-derived cytokines in pneumonia: Linking cellular immunology and genetics

Macrophages represent the first line of anti-pathogen defense - they encounter invading pathogens to perform the phagocytic activity, to deliver the plethora of pro- and anti-inflammatory cytokines, and to shape the tissue microenvironment. Throughout pneumonia course, alveolar macrophages and infiltrated blood monocytes produce increasing cytokine amounts, which activates the antiviral/antibacterial immunity but can also provoke the risk of the so-called cytokine "storm" and normal tissue damage. Subsequently, the question of how the cytokine spectrum is shaped and balanced in the pneumonia context remains a hot topic in medical immunology, particularly in the COVID19 pandemic era. The diversity in cytokine profiles, involved in pneumonia pathogenesis, is determined by the variations in cytokine-receptor interactions, which may lead to severe cytokine storm and functional decline of particular tissues and organs, for example, cardiovascular and respiratory systems. Cytokines and their receptors form unique profiles in individual patients, depending on the (a) microenvironmental context (comorbidities and associated treatment), (b) lung monocyte heterogeneity, and (c) genetic variations. These multidisciplinary strategies can be proactively considered beforehand and during the pneumonia course and potentially allow the new age of personalized immunotherapy.

Meta-analysis: Interleukin 6 gene -174G/C polymorphism associated with type 2 diabetes mellitus and interleukin 6 changes

The gene coding interleukin 6 (IL‐6) is a promising candidate in predisposition to type 2 diabetes mellitus (T2DM). This study aimed to meta‐analytically examine the association of IL‐6 gene −174G/C polymorphism with T2DM and circulating IL‐6 changes across −174G/C genotypes. Odds ratio (OR) and standard mean difference (SMD) with 95% confidence interval (CI) were calculated. Twenty‐five articles were meta‐analysed, with 20 articles for T2DM risk and 9 articles for circulating IL‐6 changes. Overall, there was no detectable significance for the association between −174G/C polymorphism and T2DM, and this association was relatively obvious under dominant model (OR: 0.82, 95% CI: 0.56‐1.21). Improved heterogeneity was seen in some subgroups, with statistical significance found in studies involving subjects of mixed races (OR: 0.63, 95% CI: 0.46‐0.86). Begg's and filled funnel plots, along with Egger's tests revealed week evidence of publication bias. In genotype‐phenotype analyses, carriers of −174CC and −174CG genotypes separately had 0.10 and 0.03 lower concentrations (pg/mL) of circulating IL‐6 than −174GG carriers. Albeit no detectable significance for the association of −174G/C with T2DM, our findings provided suggestive evidence on a dose‐dependent relation between −174G/C mutant alleles and circulating IL‐6 concentrations, indicating possible implication of this polymorphism in the pathogenesis of T2DM.

Innate and Adaptive Gene Single Nucleotide Polymorphisms Associated With Susceptibility of Severe Inflammatory Complications in Acanthamoeba Keratitis

Purpose

Over a third of patients with Acanthamoeba keratitis (AK) experience severe inflammatory complications (SICs). This study aimed to determine if some contact lens (CL) wearers with AK were predisposed to SICs due to variations in key immune genes.

Methods

CL wearers with AK who attended Moorfields Eye Hospital were recruited prospectively between April 2013 and October 2014. SICs were defined as scleritis and/or stromal ring infiltrate. Genomic DNA was processed with an Illumina Low Input Custom Amplicon assay of 58 single nucleotide polymorphism (SNP) targets across 18 genes and tested for association in PLINK.

Results

Genomic DNA was obtained and analyzed for 105 cases of AK, 40 (38%) of whom experienced SICs. SNPs in the CXCL8 gene encoding IL-8 was significantly associated with protection from SICs (chr4: rs1126647, odds ratio [OR] = 0.3, P = 0.005, rs2227543, OR = 0.4, P = 0.007, and rs2227307, OR = 0.4, P = 0.02) after adjusting for age, sex, steroids prediagnosis, and herpes simplex keratitis (HSK) misdiagnosis. Two TLR-4 SNPs were associated with increased risk of SICs (chr9: rs4986791 and rs4986790, both OR = 6.9, P = 0.01). Th-17 associated SNPs (chr1: IL-23R rs11209026, chr2: IL-1β rs16944, and chr12: IL-22 rs1179251) were also associated with SICs.

Conclusions

The current study identifies biologically relevant genetic variants in patients with AK with SICs; IL-8 is associated with a strong neutrophil response in the cornea in AK, TLR-4 is important in early AK disease, and Th-17 genes are associated with adaptive immune responses to AK in animal models. Genetic screening of patients with AK to predict severity is viable and this would be expected to assist disease management.

Identification of Smad3-related transcriptomes in type-2 diabetic nephropathy by whole transcriptome RNA sequencing

Smad3 deficiency prevents the development of type 2 diabetic nephropathy; however, the underlying molecular mechanisms remain unknown. In this study, we aimed to identify Smad3‐related genes involved in the pathogenesis of diabetic kidney disease. High‐throughput RNA sequencing was performed to profile the whole transcriptome in the diabetic kidney of Smad3 WT‐db/db, Smad3 KO‐db/db, Smad3^+/− db/db and their littermate control db/m mice at 20 weeks. The gene ontology, pathways and alternative splicing of differentially expressed protein‐coding genes and long non‐coding RNAs related to Smad3 in diabetic kidney were analysed. Compared to Smad3 WT‐db/db mice, Smad3 KO‐db/db mice exhibited an alteration of genes associated with RNA splicing and metabolism, whereas heterozygosity deletion of Smad3 (Smad3^+/− db/db mice) significantly altered genes related to cell division and cell cycle. Notably, three protein‐coding genes (Upk1b, Psca and Gdf15) and two lncRNAs (NONMMUG023520.2 and NONMMUG032975.2) were identified to be Smad3‐dependent and to be associated with the development of diabetic nephropathy. By using whole transcriptome RNA sequencing, we identified novel Smad3 transcripts related to the development of diabetic nephropathy. Thus, targeting these transcripts may represent a novel and effective therapy for diabetic nephropathy.

Cytokine Polymorphisms and Predisposition to Diabetic Nephropathy: A Meta-Analysis

BACKGROUND

Cytokine polymorphismsmight influence the predisposition to diabetic nephropathy (DN), but the results of already published related studies are still controversial and ambiguous.

OBJECTIVES

The authors designed this meta-analysis to more precisely estimate relationships between TNF-α/IL-1/IL-4/IL-8/IL-18polymorphisms and DN by pooling the results of already published related studies.

METHODS

The authors searched Pubmed, Embase, Web of Science and CNKI for already published studies. Thirty already published studies were pooled and analyzed in this meta-analysis.

RESULTS

The overall pooled meta-analysis results showed that distributions of TNF-α -238 G/A, TNF-α -308 G/A, TNF-α -1031 C/T, IL-1A -889 C/T, IL-1B -511 C/Tand IL-18 -137 G/C polymorphisms among patients and controls differed significantly. Additionally, we also found that distributions of TNF-α -308 G/A, IL-1B -511 C/T and IL-18 -137 G/C polymorphisms among patients and controls from Asians differed significantly, and the distribution of the IL-1B -511 C/T polymorphism among patients and controls from Caucasians also differed significantly.

CONCLUSION

The meta-analysis results demonstrated that TNF-α -238 G/A, TNF-α -308 G/A, TNF-α -1031 C/T, IL-1A -889 C/T, IL-1B -511 C/Tand IL-18 -137 G/Cpolymorphisms might influence predisposition to DN in the overall pooled population. Moreover, TNF-α -308 G/A, IL-1B -511 C/T and IL-18 -137 G/C polymorphisms might influence predisposition to DN in Asians, whereas the IL-1B -511 C/T polymorphism might also influence predisposition to DN in Caucasians.

Marein ameliorates diabetic nephropathy by inhibiting renal sodium glucose transporter 2 and activating the AMPK signaling pathway in db/db mice and high glucose-treated HK-2 cells

Marein, an active component of the Coreopsis tinctoria Nutt. plant, is known to improve diabetic nephropathy (DN). However, its anti-diabetic functions in DN and potential mechanisms remain unclear. The aim of this study was to elucidate the effects and mechanisms of Marein in diabetic db/db mice with DN, and in high glucose-treated HK-2 cells. In vivo, treating diabetic db/db mice with Marein for 12 consecutive weeks restored diabetes-induced hyperglycemia and dyslipidemia, and ameliorated renal function deterioration, glomerulosclerosis, and renal ectopic lipid deposition. Marein exerted renoprotective effects by directly inhibiting renal tubule sodium glucose transporter 2 (SGLT2) expression, and then activating the AMP-activated protein kinase (AMPK)/acetyl CoA carboxylase (ACC)/peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) pathway in db/db mice. Meanwhile, Marein ameliorated fibrosis and inflammation by suppressing the pro-inflammatory factors interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1), and expression of the extracellular matrix proteins, fibronectin (FN) and collagen 1 (COL1) in diabetic mice. In vitro, MDCK monolayer cells were established to explore the characteristics of Marein transmembrane transport. Marein was found to be absorbed across the membrane at a medium level that involved active transport and this was mediated by SGLTs. In HK-2 cells, Marein decreased uptake of the fluorescent glucose analog, 2-NBDG, by 22 % by inhibiting SGLT2 expression. In high glucose-treated HK-2 cells, Marein decreased SGLT2 expression and increased phosphorylated (p)-AMPK/p-ACC to improve high glucose-induced cellular dysfunction. Furthermore, Marein treatment decreased SGLT2 expression in SGLT2-overexpressing HK-2 cells. In addition, molecular docking and dynamics analysis revealed that SGLT2 was a direct target of Marein. Collectively, our results demonstrated that Marein ameliorates DN by inhibiting renal SGLT2 and activating p-AMPK, suggesting Marein can potentially prevent DN by suppressing renal SGLT2 expression directly.

The role of the TNF-α gene -308 G/A polymorphism in the development of diabetic nephropathy: An updated meta-analysis

BACKGROUND AND AIMS

Several studies have tried to link the relationship of tissue necrosis factor-alpha (TNF-α) -308 G/A polymorphism with the development of diabetic nephropathy (DN). However, these studies failed to reach a consensus due to conflicting results. This meta-analysis was done to thoroughly investigate the correlation between the polymorphism and DN development.

METHODS

To carry out the objective, patients with type 2 diabetes mellitus (T2DM) were used as controls, while patients who developed DN were utilized as cases. Eight studies (i.e., published between 2007 and 2018) were included in the present meta-analysis. Review Manager 5.3 was used to compute for the odds ratios (OR) and 95% confidence interval (CI) of the overall and post-outlier outcomes.

RESULTS

Overall, an association between DN development and the -308 G/A polymorphism was observed. However, Galbraith's plot analysis (as analyzed using Meta-Essentials) led to the removal of two studies, which significantly reduced heterogeneity. Post-outlier outcomes show significant results in the allelic (OR: 1.23; 95% CI: 1.01-1.50; p = 0.04) and co-dominant (OR: 1.60; 95% CI: 1.02-2.51; p = 0.04) models.

CONCLUSION

T2DM individuals with the -308 G/A polymorphism in the TNF-α gene are more likely to develop DN.

The association of interieukin-6 polymorphism (rs1800795) with microvascular complications in Type 2 diabetes mellitus

Objectives: To evaluate the effects of the single-nucleotide polymorphism (SNP) rs1800795 in interieukin-6 (IL-6) gene on diabetic microvascular complications of Type 2 diabetes mellitus (T2DM), using statistical meta-analysis.

Methods: Literature pertaining to the relationship between the SNP rs1800795 and microvascular complications of T2DM including diabetic retinopathy, diabetic nephropathy, diabetic neuropathy and foot disease was retrieved from PubMed, Web of Science Knowledge and SinoMed databases. Original information was analyzed using Stata 12.0, including meta-analysis statistics, test for heterogeneity, evaluation of publication bias and sensitivity. Subgroup analysis was conducted to assess the effect of specific factors on the corresponding results.

Results: In total, 14 eligible articles were obtained. The SNP rs1800795 in IL-6 gene is not correlated with risk of microvascular complications in T2DM. Among the original literature, a genetic model (OR = 1.071, 95% CI: 0.681–1.685, P=0.767), an allelic genetic model (OR = 1.010, 95% CI: 0.959–1.063, P=0.703), a heterozygote genetic model (OR = 1.107, 95% CI: 0.916–1.339, P=0.292), a dominant genetic model (OR = 1.108, 95% CI: 0.885–1.387, P=0.372), and a recessive genetic model (OR = 0.978, 95% CI: 0.646–1.478, P=0.917) were included respectively. In the subgroup analysis by types of diabetic microvascular complications, we found no correlation between the SNP rs1000795 polymorphism and complications of T2DM in either the homozygote genetic model or the allelic genetic model (P<0.05).

Conclusion: Our results demonstrate that rs1800795 polymorphism in IL-6 gene is not correlated with the susceptibility of microvascular complications of T2DM.

Effects of TNF-α-308G/A Polymorphism on the Risk of Diabetic Nephropathy and Diabetic Retinopathy: An Updated Meta-Analysis

Diabetic nephropathy (DN) and diabetic retinopathy (DR) are the major factors of morbidity and mortality in the patients with diabetes mellitus (DM). Growing studies have investigated the relationship between the TNF-α-308G/A polymorphism and the susceptibility to DN and DR, without achieving consensus. Thus, we conducted this meta-analysis to reach more comprehensive conclusions for these issues. Eligible studies were retrieved through electronic databases such as PubMed, Embase, Web of Science and China National Knowledge Infrastructure. Summary of odds ratios (OR) and 95% confidence intervals (CIs) were generated to evaluate the intensity of the associations. Statistical analyses were performed by STATA 11.0 and RevMan 5.2. There are fourteen eligible publications involving nineteen studies in this meta-analysis. TNF-α-308G/A polymorphism was significantly related to increasing risk of DN under recessive model (OR=1.37, 95% CI=1.03-1.83) and homozygous model (OR=1.54, 95% CI=1.15-2.06). Moreover, the similar results were also obtained in Asian groups for DN (recessive: OR=1.69, 95% CI=1.18-2.42; homozygous: OR=1.99, 95% CI=1.38-2.86; respectively), and significant association was also detected between TNF-α-308G/A and DN susceptibility in type 2 DM in recessive model (OR=1.39, 95% CI=1.02-1.89). No significant association was observed between TNF-α-308G/A and DR susceptibility in total analyses and subgroup analyses by ethnicity and type of DM. TNF-α-308G/A polymorphism may enhance the susceptibility to diabetic nephropathy, especially in Asian population and in T2DM patients, but not diabetic retinopathy.

LCZ696 mitigates diabetic-induced nephropathy through inhibiting oxidative stress, NF-κB mediated inflammation and glomerulosclerosis in rats

Background

Diabetic nephropathy (DN) is among the most common microvascular complications of diabetes resulting in end-stage renal disease and therefore search for candidates which can ameliorate the kidney function is needed simultaneously with standard diabetic pharmacotherapy. The current study was aimed to investigate the effect of long term sacubitril/valsartan therapy (LCZ696) in diabetic rats to assess its ameliorative impact against various pathological parameters such as oxidative stress, inflammation and glomerulosclerosis associated with chronic DN.

Methods

A single dose (60 mg/kg/day) of STZ was used to induce type 1 diabetes in adult male wistar rats. 2 weeks after diabetes induction, these rats were treated orally with valsartan (31 mg/kg) or LCZ696 (68 mg/kg) for 6 weeks. At end of the treatment period, serum and kidney samples were collected and analyzed. The serum levels of glucose, insulin, urea, creatinine, TNF-α, IL-1β, IL-6 and IL-10 levels were estimated. In renal tissue homogenate, the levels of inflammatory markers such as TNF-α, IL-1β, IL-6, NF-kB along with oxidative stress biomarkers including thiobarbituric acid-reacting substances (TBARs), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST) were assessed. Histological changes were observed in kidney.

Results

Time course therapy withLCZ696 and valsartan in diabetic rats resulted in significant reduction of serum glucose, urea and creatinine levels (P < 0.05). Additionally, serum of treated diabetic rats showed a diminution in inflammatory (TNF-α, IL-1β, IL-6) and increment in anti-inflammatory (IL-10) cytokines levels (P < 0.05). Tissue homogenate of the kidney extracted from LCZ696 and valsartan treated diabetic rats revealed a substantial reduction in the levels of inflammatory markers such as TNF-α, IL-1β, IL-6, NF-kB and sufficient restoration of anti-oxidant enzyme levels (P < 0.05). Finally, in the histological sections of the kidney, prevention of renal injury was observed with limited necrosis and inflammatory cells infiltration.

Conclusion

Present data suggest that LCZ696 has sufficient therapeutic potential to restrict DN progression through inhibiting inflammation, oxidative stress and glomerulosclerosis.

The association of TNF-α -308G/A and -238G/A polymorphisms with type 2 diabetes mellitus: a meta-analysis

Tumor necrosis factor-α (TNF-α) is involved in insulin resistance and has long been a candidate gene implicated in type 2 diabetes mellitus (T2DM), however the association between TNF-α polymorphisms -308G/A and -238G/A and T2DM remains controversial. The present study sought to verify associations between these polymorphisms and T2DM susceptibility using a meta-analysis approach. A total of 49 case-control studies were selected up to October 2018. Statistical analyses were performed by STATA 15.0 software. The odds ratios (ORs) and 95% confidence intervals were calculated to estimate associations. Meta-analyses revealed significant associations between TNF-α -308G/A and T2DM in the allele model (P=0.000); the dominant model (P=0.000); the recessive model (P=0.001); the overdominant model (P=0.008) and the codominant model (P=0.000). Subgroup analyses also showed associations in the allele model (P=0.006); the dominant model (P=0.004) and the overdominant model (P=0.005) in the Caucasian and in the allele model (P=0.007); the dominant model (P=0.014); the recessive model (P=0.000) and the codominant model (P=0.000) in the Asian. There were no associations between TNF-α -238G/A and T2DM in the overall and subgroup populations. Meta-regression, sensitivity analysis and publication bias analysis confirmed that results and data were statistically robust. Our meta-analysis suggests that TNF-α -308G/A is a risk factor for T2DM in Caucasian and Asian populations. It also indicates that TNF-α -238G/A may not be a risk factor for T2DM. More comprehensive studies will be required to confirm these associations.

Association Between IL-6 Polymorphisms and Diabetic Nephropathy Risk: A Meta-analysis

BACKGROUND

The objective of this work was to evaluate the relevance of frequent interleukin-6 (IL-6) polymorphisms and diabetic nephropathy (DN) susceptibility by a systematic meta-analysis.

MATERIALS AND METHODS

The included studies related to the relationship between IL-6 and DN risk were searched from Pubmed, Embase and the Cochrane Library, and the Newcastle-Ottawa Scale was used to evaluate the study quality. A heterogeneity test was performed to determine the appropriate effect models based on the Q test and I² statistic. Odds ratios with 95% confidence intervals were used to determine the strength of associations. Afterwards, subgroup analysis was conducted to assess the effect of specific factors on the corresponding results. Additionally, publication bias and sensitivity analysis were also undertaken.

RESULTS

In total, 11 eligible articles were obtained. The meta-analysis revealed that the "C"allele of IL-6 rs1800795 was related to the decreased risk of DN (C versus G: P = 0.0471). The "G"allele of IL-6 rs1800796 was predominately associated with higher DN risks (GG versus CC: P = 0.0194; GG versus CC + GC: P = 0.0196). The "C"allele of IL-6 rs1800797 was implicated with higher prevalence of DN (C versus G: P = 0.0001; CC versus GG: P = 0.0003; CC versus GG + CG: P = 0.0227; CC + CG versus GG: P = 0.0001) while IL-6 rs2069837 and rs2069840 were not correlated with the susceptibility to DN.

CONCLUSIONS

This meta-analysis indicated that IL-6 rs1800795, rs1800796 and rs1800797 played important roles in DN development while IL-6 rs2069837 and rs2069840 might not be related to DN.

Interleukin-1β Gene (IL1B) Polymorphism and Risk of Developing Diabetic Nephropathy

Objective: Cytokines play an important role in the pathogenesis of type 2 diabetes (T2DM) and its complications. The aim of the study was to evaluate an association of the -511 (C/T) polymorphism in the IL1B gene with diabetic nephropathy (DN). Methods: The study population included 860 patients with T2DM (506 with diabetic nephropathy and 354 without nephropathy) as well as 505 healthy individuals. Genomic DNA was genotyped for the IL1B -511 (C/T) polymorphism using PCR-RFLP technique. Results: The IL1B -511 C/T polymorphism was genotyped in 860 T2DM patients with or without DN and 505 healthy individuals. The average age of patients was 65.3 years in DN+ and 62.2 years in DN- subgroups. The genotype distribution did not differ significantly between patients and controls. Only a tendency to a slight increase of T allele frequency was observed in patient group. Genotype and allele frequencies of -511 C/T polymorphism were compared in patients with DN and those without it. The minor allele (T) and homozygote TT frequencies were significantly different between subgroups. The T allele was more frequent in DN+ patients, with odds ratio 1.45 (95% CI 1.2-1.8), p = 0.0003. The TT genotype frequency was also higher in DN+, with OR 1.76 (96% CI 1.1-2.7), p = 0.01. Conclusion: In a studied population the -511 C/T polymorphism in the IL1B gene is associated with diabetic nephropathy in dialyzed T2DM patients. Further studies are required to confirm the clinical significance of this finding.

Association of Interleukin-6 -174G/C Polymorphism with the Risk of Diabetic Nephropathy in Type 2 Diabetes: A Meta-analysis

Previous studies reported the association between interleukin-6 (IL-6) -174G/C gene polymorphism and the risk of diabetic nephropathy in type 2 diabetes mellitus (T2DN). However, the results remain controversial. In the present study, we conducted a meta-analysis to further examine this relationship between IL-6-174G/C gene polymorphism and T2DN. Three databases (PubMed, SinoMed and ISI Web of Science) were used to search clinical case-control studies about IL-6-174G/C polymorphism and T2DN published until Apr. 14, 2018. Fixed- or random-effects models were used to calculate the effect sizes of odds ratio (OR) and 95% confidence intervals (95% CI). Moreover, subgroup analysis was performed in terms of the excretion rate of albuminuria. All the statistical analyses were conducted using Stata 12.0. A total of 11 case-control studies were included in this study, involving 1203 cases of T2DN and 1571 cases of T2DM without DN. Meta-analysis showed that there was an association between IL-6-174G/C polymorphism and increased risk of T2DN under the allelic and recessive genetic models (G vs. C: OR=1.10, 95%CI 1.03-1.18, P=0.006; GG vs. CC+GC: OR=1.11, 95%CI 1.02-1.21 P=0.016). In the subgroup analysis by albuminuria, a significant association of IL-6-174G/C polymorphism with risk of T2DN was noted in the microalbuminuria group under the recessive model (OR=1.54, 95% CI 1.02-2.32, _P=0.038). In conclusion, this meta-analysis suggests that IL-6-174G/C gene polymorphism is associated with the risk of T2DN.

Long noncoding RNA NONHSAG053901 promotes diabetic nephropathy via stimulating Egr-1/TGF-β-mediated renal inflammation

Diabetic nephropathy (DN) is an important factor leading to end-stage kidney disease that affects diabetes mellitus patients globally. Our previous transcriptome sequencing has identified a large group of differentially expressed long noncoding RNA (lncRNA) in early development of DN. On basis of this, we aimed to investigate the function of lncRNA NONHSAG053901 in DN pathogenesis. In this study, we revealed that the expression of NONHSAG053901 was drastically elevated in both DN mouse model and mesangial cells (MCs). It was found that overexpression of NONHSAG053901 remarkably promoted inflammation, fibrosis and proliferation in MCs. Consistently, further investigations suggested that the stimulation of NONHSAG053901 on proinflammatory cytokines via direct binding to early growth response protein 1 (Egr-1). Interaction between Egr-1 and transforming growth factor β (TGF-β) could augment TGF-β function in DN inflammation. Furthermore, the effects of NONHSAG053901 on stimulation of proinflammatory cytokines were abolished by knockdown of Egr-1. These results together suggested that NONHSAG053901 promoted proinflammatory cytokines via stimulating Egr-1/TGF-β mediated renal inflammation.

Polymorphisms of cytokine genes and tuberculosis in two independent studies

Cytokine gene single nucleotide polymorphisms (SNPs) can influence cytokine levels, which may be associated with tuberculosis (TB) susceptibility. There is evidence that interleukin 1B (IL1B), tumor necrosis factor-alpha (TNF-alpha), and IL6 may be involved in the progression of TB. Using a self-validating case-control design, we selected eleven functional SNPs in IL1B, TNF and IL6 to detect their association with TB in Chinese Han and Tibetan populations. The associations between SNPs and TB were estimated by computing the odds ratios (ORs) and 95% confidence intervals (95% CI) using logistic regression analyses. We found that the IL1B rs16944 polymorphism was associated with decreased risk of TB in the two studies. The G allele at rs2069837 of IL6 was significantly more common in controls than in TB patients in the Han population. Moreover, TNF rs1799964 and rs1800630 were risk factors for susceptibility to TB, which were validated in the Chinese Tibetan population. In addition, TNF rs1799724 and rs1800629 were associated with TB, but only in the Tibetan population. In conclusion, SNPs of the IL1B and TNF gene were associated with TB susceptibility in Chinese Han and Tibetan populations. IL6 polymorphism may be considered as a protective factor for TB in the Chinese Han population, but not the Tibetan population.

Diabetic nephropathy: recent advances in pathophysiology and challenges in dietary management

BACKGROUND

Diabetic nephropathy (DN) or diabetic kidney disease refers to the deterioration of kidney function seen in chronic type 1 and type 2 diabetes mellitus patients. The progression of the disease is known to occur in a series of stages and is linked to glycemic and blood pressure control. However, despite aggressive blood sugar control the prevalence of chronic kidney disease (CKD) in diabetic patients has not witnessed any decrease in the last two decades; which has lead to identification of additional factors in its progression. The nutritional status of patients is an important and modifiable factor that may influence CKD processes and outcome. It directly stems from the traditional dietary choices that patients make due to poor nutritional awareness. Dietary management of DN patients is challenging, as the twin factors of diet overload on kidney function needs to be balanced with malnutrition. Patient education seems to be the key in avoiding overindulgence of carbohydrate and protein-rich foods while favoring inclusion of essential fats in their diet.

CONCLUSION

This review will summarize current advances in staging and molecular pathogenesis of DN. It will highlight recent studies focusing on patient-customized dietary interventions that offer new hope as an effective tool in improving quality of life and delaying disease progression in DN patients.