The association of genetic variants of type 2 diabetes with kidney function

mTOR Inhibition limits LPS induced acute kidney injury and ameliorates hallmarks of cellular senescence

Sepsis-induced acute kidney injury (AKI) can lead to chronic renal dysfunction with accelerated renal aging. Activation of the mammalian target of rapamycin (mTOR) is implicated in the initiation and progression of renal injury. This study investigates the effectiveness of the mTOR inhibitor, rapamycin, in mitigating kidney injury and explores the underlying mechanisms. AKI was induced by intraperitoneal administration of a solution containing 10 mg/kg of lipopolysaccharide (LPS) in a mouse model. Two groups of endotoxemic mice received pre- and post- treatment with rapamycin. Whole-genome DNA methylation analysis was performed on renal proximal tubular epithelial cells (RPTEC). In the LPS-induced AKI mouse model, rapamycin treatment significantly reduced creatinine levels, preserved renal parenchyma, and counteracted the endothelial-to-mesenchymal transition (EndMT) by inhibiting the ERK pathway. Whole-genome DNA methylation analysis revealed that LPS induced aberrant methylation, particularly in genes associated with premature aging, including ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD1/CD39) and wolframin ER transmembrane glycoprotein (WFS1). Accordingly, endotoxemic mice exhibited decreased CD39 expression and klotho down-regulation, both of which were reversed by rapamycin, suggesting an anti-aging effect in AKI. mTOR inhibition may represent a promising strategy to prevent accelerated renal aging in LPS-induced AKI and potentially slow the progression of chronic kidney disease.

Accounting for time dependency in meta-analyses of concordance probability estimates

Recent years have seen the development of many novel scoring tools for disease prognosis and prediction. To become accepted for use in clinical applications, these tools have to be validated on external data. In practice, validation is often hampered by logistical issues, resulting in multiple small-sized validation studies. It is therefore necessary to synthesize the results of these studies using techniques for meta-analysis. Here we consider strategies for meta analyzing the concordance probability for time-to-event data ("C-index"), which has become a popular tool to evaluate the discriminatory power of prediction models with a right-censored outcome. We show that standard meta-analysis of the C-index may lead to biased results, as the magnitude of the concordance probability depends on the length of the time interval used for evaluation (defined e.g., by the follow-up time, which might differ considerably between studies). To address this issue, we propose a set of methods for random-effects meta-regression that incorporate time directly as covariate in the model equation. In addition to analyzing nonlinear time trends via fractional polynomial, spline, and exponential decay models, we provide recommendations on suitable transformations of the C-index before meta-regression. Our results suggest that the C-index is best meta-analyzed using fractional polynomial meta-regression with logit-transformed C-index values. Classical random-effects meta-analysis (not considering time as covariate) is demonstrated to be a suitable alternative when follow-up times are small. Our findings have implications for the reporting of C-index values in future studies, which should include information on the length of the time interval underlying the calculations.

Association of fat mass and obesity-associated (FTO) gene polymorphisms with non-communicable diseases (NCDs) in the Iranian population: A systematic review of observational studies

Background

Single nucleotide polymorphisms have been implicated in various diseases, most notably non-communicable diseases (NCDs). The aim of this study was to review available evidence regarding associations between FTO polymorphisms and NCDs in the Iranian population.

Methods

A comprehensive search was conducted through PubMed/Medline and Scopus databases up to December 2021, as well as reference lists of pertinent articles and key journals. All observational studies that examined the association between FTO gene polymorphisms and NCDs in the Iranian population were included. There was no limitation on the publication year. The Newcastle-Ottawa Scale (NOS) was used to assess the study's quality.

Results

The initial search yielded 95 studies, of which 30 studies were included in the current systematic review. The underlying disorders were obesity, type 2 diabetes, breast and colorectal cancers, depression, and metabolic syndrome. These studies found an association between FTO gene polymorphisms and obesity in the Iranian population, but the relationship with other NCDs was debatable. Even though, other diseases such as diabetes and metabolic syndrome, which are closely related to obesity, may also be associated with FTO gene polymorphisms.

Conclusion

FTO gene polymorphism appears to play a role in the occurrence of NCDs. Some of the study results may be misleading due to ethnic differences and the effect of other genetic factors on disease onset, which needs to be investigated further. Finally, FTO gene polymorphisms can be studied as a preventive or therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01139-4.

Alteration of N6-methyladenosine epitranscriptome profiles in bilateral ureteral obstruction-induced obstructive nephropathy in juvenile rats

BACKGROUND

Urinary tract obstruction is a common cause of renal failure in children and infants, and the pathophysiological mechanisms of obstructive nephropathy are largely unclear. It has been reported that m6A modulation is involved in renal injury. However, whether m6A RNA modulation is associated with obstructive nephropathy has not yet been reported. The aim of this study was to investigate the m6A epitranscriptome profiles in the kidneys of bilateral ureteral obstruction (BUO) in young rats.

METHODS

The total level of m6A in the kidneys was measured by liquid chromatography-tandem mass spectrometry. The mRNAs of related genes were detected by real-time PCR. Methylated RNA immunoprecipitation sequencing was performed to map the epitranscriptome-wide m6A profile.

RESULTS

Global m6A levels were increased after BUO, and the mRNA expression levels of m6A methyltransferases and demethylases were significantly decreased in BUO group rat kidneys; the expression levels of EGFR and Brcal were significantly upregulated, while the mRNA expression levels of Notch1 were downregulated (P < 0.05). A total of 154 genes associated with 163 m6A peaks were identified.

CONCLUSION

The m6A epitranscriptome was significantly altered in BUO rat kidneys, which is potentially implicated in the pathophysiological processes of obstructive nephropathy.

IMPACT

The m6A RNA modification was associated with the process of renal injury in ureteral obstructive nephropathy by participating in multiple dimensions. The dysregulation of m6A methyltransferases and demethylases may be related to the pathophysiological changes of BUO-induced obstructive nephropathy. The m6A RNA modulation of the genes EGFR, Brca1, and Notch1 that were related to the regulation of aquaporin2 might be the potential mechanism for the polyuresis after ureteral obstruction.

Association of TCF7L2, CASC8 and GREM1 Polymorphisms in Patients with Colorectal Cancer and Type II Diabetes Mellitus

BACKGROUND

The aim of the study is to explore the association between the TCF7L2 rs7903146, CASC8 rs6983267 and GREM1 rs16969681 polymorphisms in patients diagnosed with type 2 diabetes mellitus (T2DM) and colorectal cancer.

METHODS

Sixty individuals were enrolled in this case-control study: thirty with colorectal cancer and type II diabetes mellitus (T2DM) and thirty healthy control individuals. Real-time PCR was used to determine the genotypes of TCF7L2 rs7903146, CASC8 rs 6983267 and GREM1 rs16969681 in patients with CRC and T2DM and in patients without T2DM and CRC. The Hardy-Weinberg equilibrium was determined in the control group for the genotype distribution of every polymorphism.

RESULTS

People carrying the TT genotype of rs7903146, rs6983267 and rs1696981 had a significant association with T2DM and CRC. Moreover, the people with the TT genotype of rs1696981 had a greater risk for T2DM and CRC (OR = 7, CI 0.397-23.347).

CONCLUSIONS

TCF7L2 rs7903146, CASC8 rs6983267 and GREM1 rs16969681 could be risk factors for the association of T2DM with CRC.

Circulating Nucleic Acid-Based Biomarkers of Type 2 Diabetes

Type 2 diabetes (T2D) is a deficiency in how the body regulates glucose. Uncontrolled T2D will result in chronic high blood sugar levels, eventually resulting in T2D complications. These complications, such as kidney, eye, and nerve damage, are even harder to treat. Identifying individuals at high risk of developing T2D and its complications is essential for early prevention and treatment. Numerous studies have been done to identify biomarkers for T2D diagnosis and prognosis. This review focuses on recent T2D biomarker studies based on circulating nucleic acids using different omics technologies: genomics, transcriptomics, and epigenomics. Omics studies have profiled biomarker candidates from blood, urine, and other non-invasive samples. Despite methodological differences, several candidate biomarkers were reported for the risk and diagnosis of T2D, the prognosis of T2D complications, and pharmacodynamics of T2D treatments. Future studies should be done to validate the findings in larger samples and blood-based biomarkers in non-invasive samples to support the realization of precision medicine for T2D.

Subproteomic profiling from renal cortices in OLETF rats reveals mutations of multiple novel genes in diabetic nephropathy

BACKGROUND

Diabetic nephropathy (DN) is a serious threat to human health, but its pathogenesis is not fully understood. Otsuka Long-Evans Tokushima Fatty (OLETF) rats are very similar to human DN in many aspects such as pathological changes and processes, and are deemed to be an ideal rodent model.

OBJECTIVE

This study was aimed to explore the pathogenesis of DN by analyzing the protein expression profile from renal cortices in OLETF rats.

METHODS

Thirty-six-week-old diabetic OLETF rats and normal control Long-Evans Tokushima Otsuka (LETO) rats were nephrectomized, and the renal cortices were isolated. The proteins were separated by soluble and insoluble high-resolution subproteomics methods for the analysis and identification of differential proteins.

RESULTS

Thirty-six differentially expressed proteins were found. Among them, 11 proteins had different isoelectric points and molecular weights between OLETF and LETO rats. Further sequencing identified point mutations in genes encoding eight of these proteins, which are involved in many biological processes closely related to DN, including oxidative stress and inflammation. Five of these eight proteins have not been reported in DN.

CONCLUSION

This study reveals mutations of multiple novel genes in diabetic OLETF rats, providing some new potential targets for the pathogenesis of DN and helping to better understand the pathogenesis of DN.

The broad pathogenetic role of TCF7L2 in human diseases beyond type 2 diabetes

The TCF7L2 protein is a key transcriptional effector of the Wnt/β‐catenin signaling pathway, regulating gene expression. It was initially identified in cancer research and embryologic developmental studies. Later, the TCF7L2 gene was linked to type 2 diabetes (T2D), implicating TCF7L2 and Wnt‐signaling in metabolic disorders and homeostasis. In fact, TCF7L2‐T2D variants confer the greatest relative risk for T2D, unquestionably predicting conversion to T2D in individuals with impaired glucose tolerance. We aim to describe the relevance of TCF7L2 in other human disorders. The TCF7L2‐single nucleotide polymorphisms (SNPs) and T2D‐risk association have been replicated in numerous follow‐up studies, and research has now been performed in several other diseases. In this article, we discuss common TCF7L2‐T2D variants within the framework of their association with human diseases. The TCF7L2 functional regions need to be further investigated because the molecular and cellular mechanisms through which TCF7L2 contributes to risk associations with different diseases are still not fully elucidated. In this review, we show the association of common TCF7L2‐T2D variants with many types of diseases. However, the role of rare genetic variations in the TCF7L2 gene in distinct diseases and ethnic groups has not been explored, and understanding their impact on specific phenotypes will be of clinical relevance. This offers an excellent opportunity to gain a clearer picture of the role that the TCF7L2 gene plays in the pathophysiology of human diseases. The potential pleiotropic role of TCF7L2 may underlie a possible pathway for comorbidity in human disorders.

Young age at diabetes diagnosis amplifies the effect of diabetes duration on risk of chronic kidney disease: a prospective cohort study

AIMS/HYPOTHESIS

We postulated that the increased lifetime risk of chronic kidney disease (CKD) in young-onset diabetes is attributable to both long disease duration and more aggressive disease. We examined whether age at diabetes diagnosis modifies the effect of diabetes duration on risk of CKD.

METHODS

We included 436,744 people with incident type 2 diabetes in the Hong Kong Diabetes Surveillance Database (HKDSD) and 16,979 people with prevalent type 2 diabetes in the Hong Kong Diabetes Register (HKDR). We used Poisson models to describe joint effects of age at diabetes diagnosis, diabetes duration and attained age on incidence of CKD in HKDSD. We used Cox proportional hazards models to examine interaction effect of age at diabetes diagnosis and diabetes duration on risk of CKD with adjustment for confounders in HKDR.

RESULTS

During a median follow-up of 5.3 years, 134,043 cases of CKD were recorded in the HKDSD. The incidence rate ratio for CKD comparing people of the same attained age but diagnosed with diabetes at ages 5 years apart was higher for people with a younger age at diabetes diagnosis, but decreased with increasing age at diabetes diagnosis. During a median follow-up of 6.3 years, 6500 people developed CKD in the HKDR. The increased risk of CKD with longer diabetes duration decreased with older age at diabetes diagnosis. The adjusted HR for CKD associated with 5 year increase in diabetes duration was 1.37 (95% CI 1.13, 1.65) in people with diabetes diagnosed at 20-29 years and 1.01 (95% CI 0.87, 1.18) in those diagnosed at ≥70 years.

CONCLUSIONS/INTERPRETATION

Young age at diabetes diagnosis amplified the effect of increasing diabetes duration on increased risk of CKD.

Multiple Single Nucleotide Polymorphism Testing Improves the Prediction of Diabetic Retinopathy Risk with Type 2 Diabetes Mellitus

Diabetic retinopathy (DR) is one of the most frequent causes of irreversible blindness, thus prevention and early detection of DR is crucial. The purpose of this study is to identify genetic determinants of DR in individuals with type 2 diabetic mellitus (T2DM). A total of 551 T2DM patients (254 with DR, 297 without DR) were included in this cross-sectional research. Thirteen T2DM-related single nucleotide polymorphisms (SNPs) were utilized for constructing genetic risk prediction model. With logistic regression analysis, genetic variations of the FTO (rs8050136) and PSMD6 (rs831571) polymorphisms were independently associated with a higher risk of DR. The area under the curve (AUC) calculated on known nongenetic risk variables was 0.704. Based on the five SNPs with the highest odds ratio (OR), the combined nongenetic and genetic prediction model improved the AUC to 0.722. The discriminative accuracy of our 5-SNP combined risk prediction model increased in patients who had more severe microalbuminuria (AUC = 0.731) or poor glycemic control (AUC = 0.746). In conclusion, we found a novel association for increased risk of DR at two T2DM-associated genetic loci, FTO (rs8050136) and PSMD6 (rs831571). Our predictive risk model presents new insights in DR development, which may assist in enabling timely intervention in reducing blindness in diabetic patients.

Alteration of N6-Methyladenosine RNA Profiles in Cisplatin-Induced Acute Kidney Injury in Mice

Aim: To identify the alterations of N6-methyladenosine (m⁶A) RNA profiles in cisplatin-induced acute kidney injury (Cis-AKI) in mice.

Materials and Methods: The total level of m⁶A and the expression of methyltransferases and demethylases in the kidneys were measured. The profiles of methylated RNAs were determined by the microarray method. Bioinformatics analysis was performed to predict the functions.

Results: Global m⁶A levels were increased after cisplatin treatment, accompanied by the alterations of Mettl3, Mettl14, Wtap, Fto, and Alkbh5. A total of 618 mRNAs and 98 lncRNAs were significantly differentially methylated in response to cisplatin treatment. Bioinformatics analysis indicated that the methylated mRNAs predominantly acted on the metabolic process.

Conclusion: M⁶A epitranscriptome might be significantly altered in Cis-AKI, which is potentially implicated in the development of nephrotoxicity.

Diabetic kidney disease in type 2 diabetes: a review of pathogenic mechanisms, patient-related factors and therapeutic options

The global prevalence of diabetic kidney disease is rapidly accelerating due to an increasing number of people living with type 2 diabetes. It has become a significant global problem, increasing human and financial pressures on already overburdened healthcare systems. Interest in diabetic kidney disease has increased over the last decade and progress has been made in determining the pathogenic mechanisms and patient-related factors involved in the development and pathogenesis of this disease. A greater understanding of these factors will catalyse the development of novel treatments and influence current practice. This review summarises the latest evidence for the factors involved in the development and progression of diabetic kidney disease, which will inform better management strategies targeting such factors to improve therapeutic outcomes in patients living with diabetes.

Potpourri: An Epistasis Test Prioritization Algorithm via Diverse SNP Selection

Genome-wide association studies (GWAS) explain a fraction of the underlying heritability of genetic diseases. Investigating epistatic interactions between two or more loci help to close this gap. Unfortunately, the sheer number of loci combinations to process and hypotheses prohibit the process both computationally and statistically. Epistasis test prioritization algorithms rank likely epistatic single nucleotide polymorphism (SNP) pairs to limit the number of tests. However, they still suffer from very low precision. It was shown in the literature that selecting SNPs that are individually correlated with the phenotype and also diverse with respect to genomic location leads to better phenotype prediction due to genetic complementation. Here, we propose that an algorithm that pairs SNPs from such diverse regions and ranks them can improve prediction power. We propose an epistasis test prioritization algorithm that optimizes a submodular set function to select a diverse and complementary set of genomic regions that span the underlying genome. The SNP pairs from these regions are then further ranked w.r.t. their co-coverage of the case cohort. We compare our algorithm with the state of the art on three GWAS and show that (1) we substantially improve precision (from 0.003 to 0.652) while maintaining the significance of selected pairs, (2) decrease the number of tests by 25-fold, and (3) decrease the runtime by 4-fold. We also show that promoting SNPs from regulatory/coding regions improves the performance (up to 0.8). Potpourri is available at http:/ciceklab.cs.bilkent.edu.tr/potpourri.

Fine mapping and identification of serum urate loci in American Indians: The Strong Heart Family Study

While studies have reported genetic loci affecting serum urate (SU) concentrations, few studies have been conducted in minority populations. Our objective for this study was to identify genetic loci regulating SU in a multigenerational family-based cohort of American Indians, the Strong Heart Family Study (SHFS). We genotyped 162,718 single nucleotide polymorphisms (SNPs) in 2000 SHFS participants using an Illumina MetaboChip array. A genome-wide association analysis of SU was conducted using measured genotype analysis approach accounting for kinships in SOLAR, and meta-analysis in METAL. Our results showed strong association of SU with rs4481233, rs9998811, rs7696092 and rs13145758 (minor allele frequency (MAF) = 25-44%; P < 3 × 10-14) of solute carrier family 2, member 9 (SLC2A9) and rs41481455, rs2231142 and rs1481012 (MAF = 29%; p < 3 × 10-9) of ATP-binding cassette protein, subfamily G, member 2 (ABCG2). Carriers of G alleles of rs9998811, rs4148155 and rs1481012 and A alleles of rs4481233, rs7696092 and rs13145758 and rs2231142 had lower SU concentrations as compared to non-carriers. Genetic analysis of SU conditional on significant SLC2A9 and ABCG2 SNPs revealed new loci, nucleobindin 1 (NUCB1) and neuronal PAS domain protein 4 (NPAS4) (p <6× 10-6). To identify American Indian-specific SNPs, we conducted targeted sequencing of key regions of SLC2A9. A total of 233 SNPs were identified of which 89 were strongly associated with SU (p < 7.1 × 10-10) and 117 were American Indian specific. Analysis of key SNPs in cohorts of Mexican-mestizos, European, Indian and East Asian ancestries showed replication of common SNPs, including our lead SNPs. Our results demonstrate the association of SU with uric acid transporters in a minority population of American Indians and potential novel associations of SU with neuronal-related genes which warrant further investigation.

Genes associated with Type 2 Diabetes and vascular complications

Type 2 Diabetes (T2D) is a chronic disease associated with a number of micro- and macrovascular complications that increase the morbidity and mortality of patients. The risk of diabetic complications has a strong genetic component. To this end, we sought to evaluate the association of 40 single nucleotide polymorphisms (SNPs) in 21 candidate genes with T2D and its vascular complications in 503 T2D patients and 580 healthy controls. The genes were chosen because previously reported to be associated with T2D complications and/or with the aging process. We replicated the association of T2D risk with IGF2BP rs4402960 and detected novel associations with TERT rs2735940 and rs2736098. The addition of these SNPs to a model including traditional risk factors slightly improved risk prediction. After stratification of patients according to the presence/absence of vascular complications, we found significant associations of variants in the CAT, FTO, and UCP1 genes with diabetic retinopathy and nephropathy. Additionally, a variant in the ADIPOQ gene was found associated with macrovascular complications. Notably, these genes are involved in some way in mitochondrial biology and reactive oxygen species regulation. Hence, our findings strongly suggest a potential link between mitochondrial oxidative homeostasis and individual predisposition to diabetic vascular complications.

The Future of Genomic Studies Must Be Globally Representative: Perspectives from PAGE

The past decade has seen a technological revolution in human genetics that has empowered population-level investigations into genetic associations with phenotypes. Although these discoveries rely on genetic variation across individuals, association studies have overwhelmingly been performed in populations of European descent. In this review, we describe limitations faced by single-population studies and provide an overview of strategies to improve global representation in existing data sets and future human genomics research via diversity-focused, multiethnic studies. We highlight the successes of individual studies and meta-analysis consortia that have provided unique knowledge. Additionally, we outline the approach taken by the Population Architecture Using Genomics and Epidemiology (PAGE) study to develop best practices for performing genetic epidemiology in multiethnic contexts. Finally, we discuss how limiting investigations to single populations impairs findings in the clinical domain for both rare-variant identification and genetic risk prediction.

Regional differences in the incidence of diabetic cardiovascular events reflect the quality of care

OBJECTIVES

Diabetic patients have two-fold excess risk of cardiovascular complications (CVCs). To compare the treatment quality of diabetic patients we compared the incidence of CVCs between the five university hospital districts (UHDs) in Finland.

DESIGN

The study population comprised all persons with diabetes in Finland since 1964. They were followed up for the incidence of first acute coronary syndrome (ACS) and first ischemic stroke (IS) using the National Hospital Discharge Register and the National Causes of Death Register data between the years 2000 and 2011. Incidence differences among diabetic patients were also compared with corresponding results in the total population. The main analysis tool was Poisson regression adjusted for age, sex and study year. The UHD of Helsinki was used as the reference category.

RESULTS

In the diabetic population the risk for ACS exceeded the reference significantly in three UHDs ranging from 1.03 (95% CI 0.89-1.19) to 1.70 (1.46-1.97). The incidence of IS exceeded the reference in two UHDs ranging from 1.01 (0.89-1.15) to 1.36 (1.18-1.56). These differences were similar to the corresponding figures in the total population. Differences between the UHDs remained stable over time.

CONCLUSIONS

We found major and stable differences in the incidence of ACS and IS between the UHDs among patients with diabetes. The differences result from several factors influencing the risk of these complications, including the treatment. These differences tended to be larger than the corresponding differences in the total population, which suggests that there is potential to prevent CVCs by improving diabetes care.

Altered expression of WFS1 and NOTCH2 genes associated with diabetic nephropathy in T2DM patients

AIM

The increased incidence of type 2 diabetes mellitus (T2DM) and the importance of early identification and management of its complications, especially diabetic nephropathy (DN), have spotted the light on genetic factors that increase risk of T2DM and its related nephropathy. The present study aimed at investigating expression of (KCNJ11, ABCC8, JAZF1, WFS1, PPARG, NOTCH2 and EXOSC4) genes in peripheral blood of T2DM patients.

METHOD

The study included 30 non-complicated T2DM patients, 30 patients with DN and 40 healthy controls. Quantitative Real Time PCR Array was used to study gene expression.

RESULTS

NOTCH2 showed higher expression while KCNJ11, JAZF1, WFS1 and PPARG genes showed lower expression in DN patients compared to non-complicated patients. KCNJ11, JAZF1, WFS1, PPARG, and EXOSC4 expression showed significant negative correlation with microalbumin, while NOTCH2 expression was significantly positively correlated with microalbumin. AS regard HbA1c and studied genes expression, there was significant negative correlation between WFS1 expression and HbA1c, while NOTCH2, KCNJ11, JAZF1, PPARG, EXOSC4 expression didn't show significant correlation with HbA1c. Risk ratio of studied genes expression showed that WFS1 and NOTCH2 had highest risk ratio (30) and highest sensitivity and specificity, in relation to DN and they were the best predictors in the group of studied genes at cut off value of ≤0.861 for WFS1 and ≥0.678 for NOTCH2.

CONCLUSION

Altered expression of WFS1 and NOTCH2 genes may play a role in pathogenesis and development of DN in patients with T2DM. These results may contribute in early identification and management of DN.

Complex Relationship between Obesity and the Fat Mass and Obesity Locus

In the 21st century, obesity has become a serious problem because of increasing obese patients and numerous metabolic complications. The primary reasons for this situation are environmental and genetic factors. In 2007, FTO (fat mass and obesity associated) was the first gene identified through a genome-wide association study (GWAS) associated with obesity in humans. Subsequently, a cluster of single nucleotide polymorphisms (SNPs) in the first intron of the FTO gene was discovered to be associated with BMI and body composition. Various studies have explored the mechanistic basis behind this association. Thus, emerging evidence showed that FTO plays a key role regulating adipose tissue development and functions in body size and composition. Recent prevalent research topic concentrated in the three neighboring genes of FTO: RPGRIP1L, IRX3 and IRX5, as having a functional link between obesity-associated common variants within FTO and the observed human phenotypes. The purpose of this review is to present a comprehensive picture of the impact of FTO on obesity susceptibility and to illuminate these new studies of FTO function in adipose tissue.

2017 update on the relationship between diabetes and colorectal cancer: epidemiology, potential molecular mechanisms and therapeutic implications

Worldwide deaths from diabetes mellitus (DM) and colorectal cancer increased by 90% and 57%, respectively, over the past 20 years. The risk of colorectal cancer was estimated to be 27% higher in patients with type 2 DM than in non-diabetic controls. However, there are potential confounders, information from lower income countries is scarce, across the globe there is no correlation between DM prevalence and colorectal cancer incidence and the association has evolved over time, suggesting the impact of additional environmental factors. The clinical relevance of these associations depends on understanding the mechanism involved. Although evidence is limited, insulin use has been associated with increased and metformin with decreased incidence of colorectal cancer. In addition, colorectal cancer shares some cellular and molecular pathways with diabetes target organ damage, exemplified by diabetic kidney disease. These include epithelial cell injury, activation of inflammation and Wnt/β-catenin pathways and iron homeostasis defects, among others. Indeed, some drugs have undergone clinical trials for both cancer and diabetic kidney disease. Genome-wide association studies have identified diabetes-associated genes (e.g. TCF7L2) that may also contribute to colorectal cancer. We review the epidemiological evidence, potential pathophysiological mechanisms and therapeutic implications of the association between DM and colorectal cancer. Further studies should clarify the worldwide association between DM and colorectal cancer, strengthen the biological plausibility of a cause-and-effect relationship through characterization of the molecular pathways involved, search for specific molecular signatures of colorectal cancer under diabetic conditions, and eventually explore DM-specific strategies to prevent or treat colorectal cancer.

Association of type 2 diabetes susceptibility loci with peripheral nerve function in a Chinese population with diabetes

Aims/Introduction

Previous studies have suggested a possible relationship between type 2 diabetes mellitus susceptibility loci and diabetic complications. The present study aimed to investigate the associations between type 2 diabetes mellitus loci with peripheral nerve function in a Chinese population with type 2 diabetes mellitus.

Materials and Methods

A total of 1,900 type 2 diabetes mellitus patients were recruited in the study. We selected ten single nucleotide polymorphisms (SNPs) from ten type 2 diabetes mellitus susceptibility genes previously confirmed in Chinese patients. Genotyping was carried out by using a MassARRAY Compact Analyzer. Peripheral nerve function was evaluated by nerve conduction studies in all participants. The composite Z‐scores for nerve conduction parameters including conduction velocity (CV), amplitude and latency were calculated, respectively.

Results

Rs5219 of KCNJ11 (E23K, G→A) was identified to be associated with all the parameters obtained from nerve conduction studies (Z‐score of CV: β = 0.113, P = 0.01; Z‐score of amplitude: β = 0.133, P = 0.01; Z‐score of latency: β = −0.116, P = 0.01) after adjustment for covariates including age, duration and glycated hemoglobin. Specifically, each copy of the A allele was related to better outcomes. CDKAL1 rs7756992 and TCF7L2 rs7903146 correlated with the composite Z‐score of amplitude (P = 0.028 and P = 0.016, respectively), but not CV (P = 0.393 and P = 0.281, respectively) or latency (P = 0.286 and P = 0.273, respectively). There were no significant associations between the other seven SNPs and peripheral nerve function.

Conclusions

Rs5219 at KCNJ11 (E23K) was associated with peripheral nerve function in a Chinese population with type 2 diabetes mellitus, suggesting shared genetic factors for type 2 diabetes mellitus and diabetic polyneuropathy in this population.

Association of the Transcription Factor 7 Like 2 (TCF7L2) Polymorphism With Diabetic Nephropathy Risk: A Meta-Analysis

It is assumed that genetic factors may participate in the development of diabetic nephropathy (DN). The association between TCF7L2 gene polymorphism and DN risk is still unclear. To evaluate the relationship, we performed this meta-analysis. Eligible relevant studies were searched and selected from PubMed, Embase, and ISI Web of Science. Summary effect estimates were derived using a random effects model, with attention to study quality and publication bias. Ethnical approval was not necessary, because this meta-analysis was based on published articles, and did not involve patient consent. A total of 7 studies were identified. Analysis of all studies indicated significant association between TCF7L2 gene polymorphism and DN risk (odds ratio [OR] = 1.31, 95% confidence interval (CI) = 1.10-1.56, Pheterogeneity < 0.00001, P = 0.002). Subgroup analysis showed similar results in Asian (OR = 1.33, 95% CI = 1.10-1.62, Pheterogeneity = 0.03, P = 0.004), in Caucasian (OR = 2.27, 95% CI = 1.78-2.90, Pheterogeneity = 0.17, P < 0.00001), in rs7903146 mutation (OR = 1.61, 95% CI = 1.25-2.07, Pheterogeneity < 0.00001, P = 0.0002), However, no association was observed in Negroid (OR = 1.10, 95% CI = 0.90-1.35, Pheterogeneity < 00001, P = 0.36). Our results suggest that TCF7L2 gene polymorphism may contribute to the risk of DN. However, more studies should be launched in the future.

Diabetic Kidney Disease: A Syndrome Rather Than a Single Disease

The term "diabetic kidney" has recently been proposed to encompass the various lesions, involving all kidney structures that characterize protean kidney damage in patients with diabetes. While glomerular diseases may follow the stepwise progression that was described several decades ago, the tenet that proteinuria identifies diabetic nephropathy is disputed today and should be limited to glomerular lesions. Improvements in glycemic control may have contributed to a decrease in the prevalence of glomerular lesions, initially described as hallmarks of diabetic nephropathy, and revealed other types of renal damage, mainly related to vasculature and interstitium, and these types usually present with little or no proteinuria. Whilst glomerular damage is the hallmark of microvascular lesions, ischemic nephropathies, renal infarction, and cholesterol emboli syndrome are the result of macrovascular involvement, and the presence of underlying renal damage sets the stage for acute infections and drug-induced kidney injuries. Impairment of the phagocytic response can cause severe and unusual forms of acute and chronic pyelonephritis. It is thus concluded that screening for albuminuria, which is useful for detecting "glomerular diabetic nephropathy", does not identify all potential nephropathies in diabetes patients. As diabetes is a risk factor for all forms of kidney disease, diagnosis in diabetic patients should include the same combination of biochemical, clinical, and imaging tests as employed in non-diabetic subjects, but with the specific consideration that chronic kidney disease (CKD) may develop more rapidly and severely in diabetic patients.

Association of TCF7L2 Polymorphism with Diabetic Nephropathy in the South Indian Population

The transcription factor 7-like 2 (TCF7L2) gene plays a significant role in the development of type 2 diabetes and diabetic nephropathy. The aim of this study was to investigate the association of TCF7L2 rs12255372 (G/T)polymorphism with type 2 diabetic nephropathy in the South Indian population. A total of 2102 subjects, 927 normal glucose tolerant (NGT) subjects, 598 type 2 diabetic subjects without nephropathy (DM), and 577 type 2 diabetic subjects with nephropathy (DN) were genotyped by MassARRAY. As compared to the NGT group, the odds ratio (adjusted for age, sex, BMI, HbA1c, and systolic BP) computed for the GT/TT genotype taking the GG genotype as reference was found to be 2.02 (95% CI: 1.16-3.51, p = 0.013) for DN and 1.94 (95% CI: 1.36-2.78, p = 0.0002) for DM. The genotype frequency was not significantly different between the DM and DN groups. In conclusion, the rs12255372 polymorphism in the TCF7L2 gene is associated with type 2 diabetes and DN but its association with DN is mediated through diabetes.

Additive protection by LDR and FGF21 treatment against diabetic nephropathy in type 2 diabetes model

The onset of diabetic nephropathy (DN) is associated with both systemic and renal changes. Fibroblast growth factor (FGF)-21 prevents diabetic complications mainly by improving systemic metabolism. In addition, low-dose radiation (LDR) protects mice from DN directly by preventing renal oxidative stress and inflammation. In the present study, we tried to define whether the combination of FGF21 and LDR could further prevent DN by blocking its systemic and renal pathogeneses. To this end, type 2 diabetes was induced by feeding a high-fat diet for 12 wk followed by a single dose injection of streptozotocin. Diabetic mice were exposed to 50 mGy LDR every other day for 4 wk with and without 1.5 mg/kg FGF21 daily for 8 wk. The changes in systemic parameters, including blood glucose levels, lipid profiles, and insulin resistance, as well as renal pathology, were examined. Diabetic mice exhibited renal dysfunction and pathological abnormalities, all of which were prevented significantly by LDR and/or FGF21; the best effects were observed in the group that received the combination treatment. Our studies revealed that the additive renal protection conferred by the combined treatment against diabetes-induced renal fibrosis, inflammation, and oxidative damage was associated with the systemic improvement of hyperglycemia, hyperlipidemia, and insulin resistance. These results suggest that the combination treatment with LDR and FGF21 prevented DN more efficiently than did either treatment alone. The mechanism behind these protective effects could be attributed to the suppression of both systemic and renal pathways.

Genetics of diabetic nephropathy: a long road of discovery

The global prevalence of diabetic nephropathy is rising in parallel with the increasing incidence of diabetes in most countries. Unfortunately, up to 40 % of persons diagnosed with diabetes may develop kidney complications. Diabetic nephropathy is associated with substantially increased risks of cardiovascular disease and premature mortality. An inherited susceptibility to diabetic nephropathy exists, and progress is being made unravelling the genetic basis for nephropathy thanks to international research collaborations, shared biological resources and new analytical approaches. Multiple epidemiological studies have highlighted the clinical heterogeneity of nephropathy and the need for better phenotyping to help define important subgroups for analysis and increase the power of genetic studies. Collaborative genome-wide association studies for nephropathy have reported unique genes, highlighted novel biological pathways and suggested new disease mechanisms, but progress towards clinically relevant risk prediction models for diabetic nephropathy has been slow. This review summarises the current status, recent developments and ongoing challenges elucidating the genetics of diabetic nephropathy.

Diabetes and Kidney Disease in American Indians: Potential Role of Sugar-Sweetened Beverages

Since the early 20th century, a marked increase in obesity, diabetes, and chronic kidney disease has occurred in the American Indian population, especially the Pima Indians of the Southwest. Here, we review the current epidemic and attempt to identify remediable causes. A search was performed using PubMed and the search terms American Indian and obesity, American Indian and diabetes, American Indian and chronic kidney disease, and American Indian and sugar or fructose, Native American, Alaska Native, First Nations, Aboriginal, Amerind, and Amerindian for American Indian for articles linking American Indians with diabetes, obesity, chronic kidney disease, and sugar; additional references were identified in these publications traced to 1900 and articles were reviewed if they were directly discussing these topics. Multiple factors are involved in the increased risk for diabetes and kidney disease in the American Indian population, including poverty, overnutrition, poor health care, high intake of sugar, and genetic mechanisms. Genetic factors may be especially important in the Pima, as historical records suggest that this group was predisposed to obesity before exposure to Western culture and diet. Exposure to sugar-sweetened beverages may also be involved in the increased risk for chronic kidney disease. In these small populations in severe health crisis, we recommend further studies to investigate the role of excess added sugar, especially sugar-sweetened beverages, as a potentially remediable risk factor.

Validation of the association of TCF7L2 and SLC30A8 gene polymorphisms with post-transplant diabetes mellitus in Asian Indian population

The rs7903146 and rs13266634 polymorphisms in the TCF7L2 and SLC30A8 genes, respectively, have been reported to be associated with type 2 diabetes. However, little is known about the association of these polymorphisms with post-transplant diabetes mellitus (PTDM). To study this linkage, we determined a distribution of allele and genotype frequencies in Asian Indians. 42 PTDM and 98 non-PTDM subjects were recruited. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was performed to detect for rs7903146 and rs13266634 polymorphisms. The clinical details and statistical analysis for PTDM and non-PTDM subjects were recorded. Our results observed higher frequencies of the minor alleles in rs7903146 and rs13266634 polymorphisms in the PTDM group compared to the non-PTDM subjects. The allele frequencies also found to be significantly associated with PTDM (rs7903146: T vs C: OR-2.6; (95%CI: 1.2-5.6); p = 0.01; rs13266634: T vs C: OR-2.0; (95%CI: 1.1-3.4); p = 0.01). These findings suggest that rs7903146 and rs13266634 polymorphisms are associated with PTDM in the Asian Indian population despite a relatively small study group.

T-cell cytokine gene polymorphisms and vitamin D pathway gene polymorphisms in end-stage renal disease due to type 2 diabetes mellitus nephropathy: comparisons with health status and other main causes of end-stage renal disease

BACKGROUND

T-cell cytokine gene polymorphisms and vitamin D pathway gene polymorphisms were evaluated as possibly associated with end-stage renal disease (ESRD) resulting from type 2 diabetes mellitus (DM) nephropathy.

METHODS

Studies were conducted among hemodialysis (HD) patients with ESRD due to type 2 DM nephropathy, chronic glomerulonephritis, chronic infective tubulointerstitial nephritis, and hypertensive nephropathy as well as in healthy subjects. A frequency distribution of T-cell-related interleukin (IL) genes (IL18 rs360719, IL12A rs568408, IL12B rs3212227, IL4R rs1805015, IL13 rs20541, IL28B rs8099917, IL28B, and rs12979860) and vitamin D pathway genes (GC genes: rs2298849, rs7041, and rs1155563; VDR genes: rs2228570, rs1544410; and RXRA genes: rs10776909, rs10881578, and rs749759) was compared between groups.

RESULTS

No significant differences in a frequency distribution of tested polymorphisms were shown between type 2 DM nephropathy patients and controls. A difference was found in IL18 rs360719 polymorphic distribution between the former group and chronic infective tubulointerstitial nephritic patients (P trend = 0.033), which also differed in this polymorphism from controls (P trend = 0.005).

CONCLUSION

T-cell cytokine and vitamin D pathway gene polymorphisms are not associated with ESRD due to type 2 DM nephropathy in Polish HD patients. IL18 rs360719 is probably associated with the pathogenesis of chronic infective tubulointerstitial nephritis.

Risk of chronic kidney disease in type 2 diabetes determined by polymorphisms in NOS3, APOB, KCNJ11, TCF7L2 genes as compound effect of risk genotypes combination

Genetic susceptibility plays an important role in the risk of developing chronic complications in patients with type 2 diabetes mellitus (T2DM). Aims. In this study, we evaluated the possible association of the polymorphic variants that encode key renal damage mediators (endothelial dysfunction, lipid metabolism and insulin secretion/sensitivity) with the risk of chronic kidney disease (CKD) in patients with T2DM. Materials and Methods. We enrolled 435 patients with T2DM using case-control study design. In 253 patients, we used non-overlapping criteria to form groups with/without CKD (defined as GFR=10 years) (n=75 and 178, respectively) and analysed the following 4 polymorphic markers: I/D in ACE, ecNOS4a/4b in NOS3, I/D in APOB and e2/e3/e4 in APOE genes. We then divided 182 patients in groups with/without CKD (n=38 and 144, respectively) regardless of the duration of diabetes and studied pro12ala in PPARG2, rs5219 in KCNJ11, rs12255372 in TCF7L2 and rs13266634 in SLC30A8 genes. 2 test, and data were expressed as odds ratios (ORs) with 95% confidence intervals (CIs). Values of p

Genetic and epigenetic risk factors for diabetic kidney disease

Diabetes is increasing at daunting rates worldwide, and approximately 40% of affected individuals will develop kidney complications. Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and there are significant healthcare costs providing appropriate renal replacement therapies to affected individuals. For several decades, investigators have sought to discover inherited risk factors and biomarkers for DKD. In recent years, advances in high-throughput laboratory techniques and computational analyses, coupled with the establishment of multicenter consortia, have helped to identify genetic loci that are replicated across multiple populations. Several genome-wide association studies (GWAS) have been conducted for DKD with further meta-analysis of GWAS and comprehensive "single gene" meta-analyses now published. Despite these efforts, much of the inherited predisposition to DKD remains unexplained. Meta-analyses and integrated-omics pathway studies are being used to help elucidate underlying genetic risks. Epigenetic phenomena are increasingly recognized as important drivers of disease risk, and several epigenome-wide association studies have now been completed. This review describes key findings and ongoing genetic and epigenetic initiatives for DKD.

Multiple low-dose radiation prevents type 2 diabetes-induced renal damage through attenuation of dyslipidemia and insulin resistance and subsequent renal inflammation and oxidative stress

BACKGROUND

Dyslipidemia and lipotoxicity-induced insulin resistance, inflammation and oxidative stress are the key pathogeneses of renal damage in type 2 diabetes. Increasing evidence shows that whole-body low dose radiation (LDR) plays a critical role in attenuating insulin resistance, inflammation and oxidative stress.

OBJECTIVE

The aims of the present study were to investigate whether LDR can prevent type 2 diabetes-induced renal damage and the underlying mechanisms.

METHODS

Mice were fed with a high-fat diet (HFD, 40% of calories from fat) for 12 weeks to induce obesity followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg) to develop a type 2 diabetic mouse model. The mice were exposed to LDR at different doses (25, 50 and 75 mGy) for 4 or 8 weeks along with HFD treatment. At each time-point, the kidney weight, renal function, blood glucose level and insulin resistance were examined. The pathological changes, renal lipid profiles, inflammation, oxidative stress and fibrosis were also measured.

RESULTS

HFD/STZ-induced type 2 diabetic mice exhibited severe pathological changes in the kidney and renal dysfunction. Exposure of the mice to LDR for 4 weeks, especially at 50 and 75 mGy, significantly improved lipid profiles, insulin sensitivity and protein kinase B activation, meanwhile, attenuated inflammation and oxidative stress in the diabetic kidney. The LDR-induced anti-oxidative effect was associated with up-regulation of renal nuclear factor E2-related factor-2 (Nrf-2) expression and function. However, the above beneficial effects were weakened once LDR treatment was extended to 8 weeks.

CONCLUSION

These results suggest that LDR exposure significantly prevented type 2 diabetes-induced kidney injury characterized by renal dysfunction and pathological changes. The protective mechanisms of LDR are complicated but may be mainly attributed to the attenuation of dyslipidemia and the subsequent lipotoxicity-induced insulin resistance, inflammation and oxidative stress.

Transcription factor 7-like 2 (TCF7L2) gene polymorphism and clinical phenotype in end-stage renal disease patients

Variants of the transcription factor 7-like 2 gene (TCF7L2) have been associated with type 2 diabetes and cardiovascular disease in different populations. Here we investigated the potential association of the rs7903146 polymorphism in the TCF7L2 gene with clinical profile of end-stage renal disease (ESRD) patients. We examined a cohort of 1065 ESRD patients with diabetic and non-diabetic renal disease. The control group consisted of 924 healthy individuals. All subjects were genotyped for the rs7903146 single nucleotide polymorphism by polymerase chain reaction. The genotype distribution and allele frequencies were significantly different between ESRD patients and controls (p < 0.01). The OR for the TT genotype was 2.81 (95 % CI 2.08–3.79). Genotype and allele frequencies were compared between subgroups of patients with different clinical phenotypes. The frequency of the T allele was significantly higher in patients with diabetic nephropathy versus non-diabetic renal disease (p = 0.007, OR 1.70, 95 % CI 1.36–2.11). The statistically significant differences were demonstrated between patients with and without cardiovascular disease, with the OR for T allele 1.57 (95 % CI 1.31–1.90). The odds ratio for TT genotype was 2.38 (95 % CI 1.62–3.51). In our study the T allele of the rs7903146 SNP in the TCF7L2 gene confers the risk of developing diabetic nephropathy. We described for the first time a strong relationship between the TCF7L2 gene variant rs7903146 and cardiovascular disease in end-stage renal disease patients.

The bigger picture of FTO: the first GWAS-identified obesity gene

Single nucleotide polymorphisms (SNPs) that cluster in the first intron of fat mass and obesity associated (FTO) gene are associated obesity traits in genome-wide association studies. The minor allele increases BMI by 0.39 kg/m(2) (or 1,130 g in body weight) and risk of obesity by 1.20-fold. This association has been confirmed across age groups and populations of diverse ancestry; the largest effect is seen in young adulthood. The effect of FTO SNPs on obesity traits in populations of African and Asian ancestry is similar or somewhat smaller than in European ancestry populations. However, the BMI-increasing allele in FTO is substantially less prevalent in populations with non-European ancestry. FTO SNPs do not influence physical activity levels; yet, in physically active individuals, FTO's effect on obesity susceptibility is attenuated by approximately 30%. Evidence from epidemiological and functional studies suggests that FTO confers an increased risk of obesity by subtly changing food intake and preference. Moreover, emerging data suggest a role for FTO in nutrient sensing, regulation of mRNA translation and general growth. In this Review, we discuss the genetic epidemiology of FTO and discuss how its complex biology might link to the regulation of body weight.

A genome-wide search for linkage of estimated glomerular filtration rate (eGFR) in the Family Investigation of Nephropathy and Diabetes (FIND)

Objective

Estimated glomerular filtration rate (eGFR), a measure of kidney function, is heritable, suggesting that genes influence renal function. Genes that influence eGFR have been identified through genome-wide association studies. However, family-based linkage approaches may identify loci that explain a larger proportion of the heritability. This study used genome-wide linkage and association scans to identify quantitative trait loci (QTL) that influence eGFR.

Methods

Genome-wide linkage and sparse association scans of eGFR were performed in families ascertained by probands with advanced diabetic nephropathy (DN) from the multi-ethnic Family Investigation of Nephropathy and Diabetes (FIND) study. This study included 954 African Americans (AA), 781 American Indians (AI), 614 European Americans (EA) and 1,611 Mexican Americans (MA). A total of 3,960 FIND participants were genotyped for 6,000 single nucleotide polymorphisms (SNPs) using the Illumina Linkage IVb panel. GFR was estimated by the Modification of Diet in Renal Disease (MDRD) formula.

Results

The non-parametric linkage analysis, accounting for the effects of diabetes duration and BMI, identified the strongest evidence for linkage of eGFR on chromosome 20q11 (log of the odds [LOD] = 3.34; P = 4.4×10⁻⁵) in MA and chromosome 15q12 (LOD = 2.84; P = 1.5×10⁻⁴) in EA. In all subjects, the strongest linkage signal for eGFR was detected on chromosome 10p12 (P = 5.5×10⁻⁴) at 44 cM near marker rs1339048. A subsequent association scan in both ancestry-specific groups and the entire population identified several SNPs significantly associated with eGFR across the genome.

Conclusion

The present study describes the localization of QTL influencing eGFR on 20q11 in MA, 15q21 in EA and 10p12 in the combined ethnic groups participating in the FIND study. Identification of causal genes/variants influencing eGFR, within these linkage and association loci, will open new avenues for functional analyses and development of novel diagnostic markers for DN.

Association study of genetic variants of 17 diabetes-related genes/loci and cardiovascular risk and diabetic nephropathy in the Chinese She population

BACKGROUND

Genetic determinations are important in type 2 diabetes (T2DM) pathology. We investigated associations between genetic variants of 17 diabetes-related genes/loci, T2DM and diabetic complications in Chinese She subjects.

METHODS

A comprehensive gene-based association study was conducted using 17 single nucleotide polymorphisms in Chinese She subjects with normal glucose tolerance (n = 1119), impaired glucose regulation (n = 1767), and T2DM (n = 443). We applied major abnormal Minnesota Code findings to predict cardiovascular risk and estimated glomerular filtration rate to assess kidney function.

RESULTS

Nine variants in FTO rs8050136, WFS1 rs10010131, CDKN2A/B rs10811661, KCNJ11 rs5219, CDC123/CAMK1D rs12779790, JAZF1 rs864745, SLC30A8 rs13266634, CDKAL1 rs10946398, and HHEX/IDE rs5015480 were significantly associated with T2DM (P < 0.05). Single nucleotide polymorphisms in WFS1 rs10010131, CDKN2A/B rs10811661, CDC123/CAMK1D rs12779790, JAZF1 rs864745, FTO rs8050136, and HHEX/IDE rs5015480 were associated with T2DM and impaired glucose regulation. Risk alleles in WFS1 rs10010131, IGF2BP2 rs4402960, CDKAL1 rs10946398, FTO rs8050136, KCNQ1 rs2237897, and ADAMTS9 rs4607103 were significantly associated with decreased homeostatic model assessment (HOMA)-β (P < 0.05). After adjusting for age, gender and body mass index, genetic variants JAZF1 rs864745, FTO rs8050136, and HHEX/IDE rs5015480 were significantly related to reduced estimated glomerular filtration rate (P < 0.05). Genetic variants in WFS1 rs10010131, CDKN2A/B rs10811661, CDC123/CAMID rs12779790, JAZF1 rs864745, FTO rs80501360, CDKAL1 rs10946398, and HHEX/IDE rs5015480 correlated with abnormal major Minnesota Code findings (P < 0.05).

CONCLUSION

Variants in WFS1, CDKN2A/B, KCNJ11, CDC123/CAMK1D, JAZF1, SLC30A8, FTO, CDKAL1, and HHEX/IDE genes are significantly associated with T2DM in She Chinese subjects. JAZF1, FTO, CDKAL1, and HHEX/IDE are associated with diabetic nephropathy. WFS1, CDKN2A/B, CDC123/CAMK1D, JAZF1, FTO, CDKAL1, and HHEX/IDE are associated with cardiovascular risk.

Novel roles of complement in renal diseases and their therapeutic consequences

The complement system functions as a part of the innate immune system. Inappropriate activation of the complement pathways has a deleterious effect on kidneys. Recent advances in complement research have provided new insights into the pathogenesis of glomerular and tubulointerstitial injury associated with complement activation. A new disease entity termed 'C3 glomerulopathy' has recently been proposed and is characterized by isolated C3 deposition in glomeruli without positive staining for immunoglobulins. Genetic and functional studies have demonstrated that several different mutations and disease variants, as well as the generation of autoantibodies, are potentially associated with its pathogenesis. The data from comprehensive analyses suggest that complement dysregulation can also be associated with hemolytic uremic syndrome and more common glomerular diseases, such as IgA nephropathy and diabetic kidney disease. In addition, animal studies utilizing genetically modified mice have begun to elucidate the molecular pathomechanisms associated with the complement system. From a diagnostic point of view, a noninvasive, MRI-based method for detecting C3 has recently been developed to serve as a novel tool for diagnosing complement-mediated kidney diseases. While novel therapeutic tools related to complement regulation are emerging, studies evaluating the precise roles of the complement system in kidney diseases will still be useful for developing new therapeutic approaches.

Silencing of the WFS1 gene in HEK cells induces pathways related to neurodegeneration and mitochondrial damage

The gene WFS1 encodes a protein with unknown function although its functional deficiency causes different neuropsychiatric and neuroendocrine syndromes. In the present study, we aimed to find the functional networks influenced by the time-dependent silencing of WFS1 in HEK cells. We performed whole genome gene expression profiling (Human Gene 1.0 ST Arrays) in HEK cells 24, 48, 72, and 96 h after transfection with three different WFS1 siRNAs. To verify silencing we performed quantitative RT-PCR and Western blot analysis. Analysis was conducted in two ways. First we analyzed the overall effect of the siRNA treatment on the gene expression profile. As a next step we performed time-course analysis separately for different siRNAs and combined for all siRNAs. Quantitative RT-PCR and Western blot analysis confirmed clear silencing of the expression of WFS1 after 48 h. Significant (FDR value<10%) changes in the expression of 11 genes was identified with most of these genes being related to the mitochondrial dysfunction and apoptosis. Time-course analysis confirmed significant correlations between WFS1 silencing and changes in the expression profiles of several genes. The pathways that were influenced significantly by WFS1 silencing were related to mitochondrial damage and neurodegenerative diseases. Our findings suggest a role of WFS1 gene in cell survival and its involvement in degenerative diseases.