Association of variant rs7903146 (C/T) single nucleotide polymorphism of TCF7L2 gene with impairment in wound healing among north Indian type 2 diabetes population: a case-control study

A comprehensive review on the development of chiral Cu, Ni, and Zn complexes as pharmaceutical agents over the past decades: Synthesis, molecular structure and biological activity

Chirality is a fundamental and widespread geometric structural property in living organisms that most biomacromolecules including nucleic acids, proteins and enzymes, possess. Consequently, the development of chiral drugs capable of binding specific targets have gradually gained wide attention in recent decades due to their selective effects on a broad spectrum of biological events ranging from cell metabolism to cell fate. In this context, the synthesis of chiral compounds as promising therapeutic candidates has assumed a major role in drug discovery. Among them, chiral metal complexes have attracted considerable interest due to their unique and intriguing structural features that could enable overcoming side effects and drug-resistance phenomena of metal-based drugs currently in the market such as cisplatin. In the current scenario, an in-depth overview of non-platinum chiral complexes needs to be presented and carried forward. Therefore, in this perspective article, an update of the scientific development of bioactive chiral copper, zinc and nickel complexes have been reported since they have not been thoroughly reviewed so far. Specifically, we focused the article mainly on metal complexes containing chiral ligands (type 2 chirality) as in literature they are more numerous than those with chirality at the metal center (type 1 chirality). Herein, not only their biological activity but also their mechanism of action is summarized. Furthermore, in the final section of the article we have highlighted copper-based complexes as those with a superior biological activity profile and greater prospects for development as a drug.

Assessment of potential genetic markers for diabetic foot ulcer among Moscow residents

PURPOSE

Diabetic foot ulcer (DFU) is one of the most severe complications of type 2 diabetes, which is manifested in chronic skin ulcers of lower extremities. DFU treatment remains complex and expensive despite the availability of well-established protocols. Early prediction of potential DFU development at the onset of type 2 diabetes can greatly improve the aftermath of this complication.

METHODS

To assess potential genetic markers for DFU, a group of diabetic patients from Moscow region with and without DFU was genotyped for a number of SNPs previously reported to be associated with the DFU.

RESULTS

Obtained results did not confirm previously claimed association of rs1024611, rs3918242, rs2073618, rs1800629, rs4986790, rs179998, rs1963645 and rs11549465 (respectively, in MCP1, MMP9, TNFRSF11B, TNFα, TLR4, eNOS, NOS1AP and HIF1α genes) with the DFU. Surprisingly, the t allele of rs7903146 in the TCF7l2 gene known as one of the most prominent risk factors for type 2 diabetes has shown a protective effect on DFU with OR(95%) = 0.68(0.48-0.96).

CONCLUSION

Non-replication of previously published SNP associations with DFU suggests that the role of genetic factors in the DFU onset is either highly variable in different populations or is not as significant as the role of non-genetic factors.

Epigenetic basis of diabetic vasculopathy

Type 2 diabetes mellitus (T2DM) causes peripheral vascular disease because of which several blood-borne factors, including vital nutrients fail to reach the affected tissue. Tissue epigenome is sensitive to chronic hyperglycemia and is known to cause pathogenesis of micro- and macrovascular complications. These vascular complications of T2DM may perpetuate the onset of organ dysfunction. The burden of diabetes is primarily because of a wide range of complications of which nonhealing diabetic ulcers represent a major component. Thus, it is imperative that current research help recognize more effective methods for the diagnosis and management of early vascular injuries. This review addresses the significance of epigenetic processes such as DNA methylation and histone modifications in the evolution of macrovascular and microvascular complications of T2DM.

Single nucleotide polymorphisms in cytokine/chemokine genes are associated with severe infection, ulcer grade and amputation in diabetic foot ulcer

Compared to other complications the genetics of diabetic foot ulcer is poorly studied. The Interleukin (IL)-6 (-174G > C/rs1800795), Tumor Necrosis Factor (TNF)-α (-308G > A/rs1800629) and (-238G > A/rs361525) and Stromal cell Derived Factor (SDF)-1 (+801G > A/rs1801157) are well characterized single nucleotide polymorphisms (SNPs) which were previously shown to be associated with Diabetic Foot Ulcer (DFU). In the present study, we looked at the association of these SNPs with foot microbial infection, Wagner's ulcer grade and treatment procedure, along with serum levels of these cytokines (intermediate phenotype) and other serum biomarkers (adiponectin, leptin, CRP and HOMA-IR) in subjects with DFU. Subjects with DFU (n = 270) were genotyped by PCR-RFLP and the serum levels of IL-6, TNF-α and SDF-1 were determined by ELISA. Microbial infections were determined by standard microbiological methods. Ulcer grade and treatment procedures were recorded. IL-6 (-174G > C), TNF-α (-308G > A) and SDF-1 (+801G > A) SNPs were associated with severe microbial infections. TNF-α (-308G > A) and (-238G > A) SNPs were associated with severe ulcer grades. SDF-1 (+801G > A) SNP was associated with major amputation even after adjusting for confounding variables. Identification of these SNPs in DFU subjects would help in identifying high risk individuals who need better treatment care.

Toll-like receptors-2 and -9 (TLR2 and TLR9) gene polymorphism in patients with type 2 diabetes and diabetic foot

Toll-like receptors (TLRs) are innate immune receptors that mediate the inflammatory response in diabetes mellitus (DM). The aim of this study is to evaluate the association of TLR2 and TLR9 gene polymorphism in patients with type 2 DM (T2DM) and diabetic foot (DF).The study included 90 subjects divided into group I (30 patients with T2DM and DF), group II (30 patients with T2DM and no evidence of DF), and group III (normal control subjects). TLR2 (1350 T/C, rs3804100) and TLR9 (1237 T/C, rs5743836) genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique for all subjects.There was a statistically significant difference in the distribution of TLR9-1237 T/C genotypes between groups I and II (P < .029) as well as between groups I and III (P < .001). Calculated risk estimation revealed that TLR9-1237 polymorphism conferred almost 20 times increased risk of DF disorders in T2DM (OR = 20, 95% CI = 5.38-74.30). There was no statistical difference in the distribution of TLR2-1350T/C genotypes between the 3 groups.TLR9-1237 T/C gene polymorphism may be considered as a molecular risk for DF among patients with T2DM.

Evaluation of VEGF gene polymorphisms and proliferative diabetic retinopathy in Mexican population

AIM

To assess if the included vascular endothelial growth factor (VEGF) polymorphisms rs3025035, rs3025021 and rs2010963 are associated to proliferative retinopathy in a Mexican population with type 2 diabetes mellitus (T2DM).

METHODS

A case-control study was conducted in adult individuals with T2DM associated to proliferative retinopathy or non-proliferative retinopathy from Oct. 2014 to Jun. 2015 from the Retina Department of the Asociation to Prevent Blindness in Mexico. The selected patients were adults with a diagnosis of T2DM ≥5y. All subjects had a comprehensive ocular examination and the classification of the retinopathy severity was made considering the Early Treatment Diabetic Retinopathy Study (ETDRS) standardization protocols. Genomic DNA was extracted from whole fresh blood. All samples were genotyped by qPCR for selected VEGF polymorphisms. Hardy-Weinberg equilibrium was calculated by comparing Chi-square values between the expected and the observed values for genotype counts.

RESULTS

In total 142 individuals were enrolled, 71 individuals with T2DM and associated proliferative retinopathy and 71 individuals with non-proliferative retinopathy. One-sided Fisher's exact test was performed for rs3025021 [OR (95% CI)=0.44(0.08-2.2); P=0.25] and rs2010963 [OR (95% CI)=0.63(0.25-1.6); P=0.23]. The minor allelic frequencies obtained were 26% for rs3025021, 10% for rs3025035 and 61% for rs2010963. The pairwise linkage disequilibrium between the three SNP was assessed, and was as follows: rs3025021 vs rs3025035: D'=1.0, r²=0.1043, P≤0.0001; rs3025021 vs rs2010963: D'=0.442, r²=0.0446, P=0.149; rs3025035 vs rs2010963: D'=0.505, r²=0.0214, P=0.142.

CONCLUSION

This is the first analysis involving VEGF polymorphisms and proliferative diabetic retinopathy in a Mexican population. A major finding of the present study is that none of the polymorphisms studied was significantly associated with proliferative retinopathy. Based on these results, we can infer that different populations have different associations for the same polymorphisms.

Decreased expression of heat shock proteins may lead to compromised wound healing in type 2 diabetes mellitus patients

BACKGROUND

Heat shock proteins (HSPs) are inducible stress proteins expressed in cells exposed to stress. HSPs promote wound healing by recruitment of dermal fibroblasts to the site of injury and bring about protein homeostasis. Diabetic wounds are hard to heal and inadequate HSPs may be important contributors in the etiology of diabetic foot ulcers (DFU).

OBJECTIVE

To analyze the differential expression of HSPs and their downstream molecules in human diabetic wounds compared to control wounds.

METHODS

Expressional levels of HSP27, HSP47 and HSP70 and their downstream molecules like TLR4, p38-MAPK were seen in biopsies from 101 human diabetic wounds compared to 8 control subjects without diabetes using RT-PCR, western blot and immunohistochemistry.

RESULTS

Our study suggested a significant down regulation of HSP70, HSP47 and HSP27 (p value=<0.001 for HSP70; p value=0.007 for HSP47; p value=0.007 for HSP27) in DFU along with their downstream molecules TLR4 and p38-MAPK (p value=0.006 for p38-MAPK; p value=0.02 for TLR4). HSP70 levels were significantly lower in male subjects and their levels increased significantly with the grades of wound on Wagner's scale. Infection status of the wounds was found to be significantly associated with the increased levels of HSP70 and HSP27 in infected diabetic wounds.

CONCLUSIONS

Our study demonstrates that the down regulation of HSPs in diabetic wounds is associated with wound healing impairment in T2DM subjects.

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.

Genetic and epigenetic alterations in Toll like receptor 2 and wound healing impairment in type 2 diabetes patients

AIM

Persistent hyperglycemic microenvironment in type 2 diabetes mellitus (T2DM) leads to the development of secondary complications like wound healing impairment. Proper co-ordination of innate immune system plays an integral role in wound healing. Toll like receptors (TLRs) are prominent contributors for the induction of the innate immune and inflammation response. TLR2 is an important extracellular member in mammalian TLR family and has been shown to be a potent player in the wound healing mechanism.

METHODS

Expressional status of TLR2 was seen in wounds of T2DM cases with respect to the severity of wounds in 110 human lower extremity wounds. The methylation status of TLR2 promoter was also examined.

RESULTS

Although TLR2 transcripts were downregulated in T2DM wounds compared to control, their levels tend to increase with the severity of T2DM wounds. The methylation status of TLR2 gene promoter was not significantly different among different grades of wounds in T2DM subjects. The CpG sites investigated were totally or partially methylated in majority of DFU cases.

CONCLUSION

TLR2 down regulation in wounds of T2DM patients compared to non diabetic patients may lead to development of non healing chronic ulcers in them.

Developing discriminate model and comparative analysis of differentially expressed genes and pathways for bloodstream samples of diabetes mellitus type 2

Background

Diabetes mellitus of type 2 (T2D), also known as noninsulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes, is a common disease. It is estimated that more than 300 million people worldwide suffer from T2D. In this study, we investigated the T2D, pre-diabetic and healthy human (no diabetes) bloodstream samples using genomic, genealogical, and phonemic information. We identified differentially expressed genes and pathways. The study has provided deeper insights into the development of T2D, and provided useful information for further effective prevention and treatment of the disease.

Results

A total of 142 bloodstream samples were collected, including 47 healthy humans, 22 pre-diabetic and 73 T2D patients. Whole genome scale gene expression profiles were obtained using the Agilent Oligo chips that contain over 20,000 human genes. We identified 79 significantly differentially expressed genes that have fold change ≥ 2. We mapped those genes and pinpointed locations of those genes on human chromosomes. Amongst them, 3 genes were not mapped well on the human genome, but the rest of 76 differentially expressed genes were well mapped on the human genome. We found that most abundant differentially expressed genes are on chromosome one, which contains 9 of those genes, followed by chromosome two that contains 7 of the 76 differentially expressed genes. We performed gene ontology (GO) functional analysis of those 79 differentially expressed genes and found that genes involve in the regulation of cell proliferation were among most common pathways related to T2D. The expression of the 79 genes was combined with clinical information that includes age, sex, and race to construct an optimal discriminant model. The overall performance of the model reached 95.1% accuracy, with 91.5% accuracy on identifying healthy humans, 100% accuracy on pre-diabetic patients and 95.9% accuract on T2D patients. The higher performance on identifying pre-diabetic patients was resulted from more significant changes of gene expressions among this particular group of humans, which implicated that patients were having profound genetic changes towards disease development.

Conclusion

Differentially expressed genes were distributed across chromosomes, and are more abundant on chromosomes 1 and 2 than the rest of the human genome. We found that regulation of cell proliferation actually plays an important role in the T2D disease development. The predictive model developed in this study has utilized the 79 significant genes in combination with age, sex, and racial information to distinguish pre-diabetic, T2D, and healthy humans. The study not only has provided deeper understanding of the disease molecular mechanisms but also useful information for pathway analysis and effective drug target identification.

Differential Expression of Matrix Metalloproteinase-9 Gene in Wounds of Type 2 Diabetes Mellitus Cases With Susceptible -1562C>T Genotypes and Wound Severity

Coordinated extracellular matrix deposition is a prerequisite for proper wound healing which is mainly orchestrated by matrix metalloproteinases (MMPs). Diabetic wounds generally show compromised wound healing cascade and abnormal MMP9 concentration is one of the cause. Our group have recently shown that the polymorphism -1562 C>T in the promoter region of MMP9 gene is associated with pathogenesis of wound healing impairment in T2DM patients. In present study we have done expression profiling of MMP9 gene in the wound biopsy of DFU cases. Expression level of MMP9 mRNA was then compared with susceptible -1562 C>T genotypes (TT and CT) as well as with different grades of wounds. We also screened the promoter region of MMP9 gene to see the methylation state of CpGs present there. Our study suggests that levels of MMP9 mRNA increase significantly with the wound grades. Moreover, the MMP9 levels in diabetic wounds were also dependent on -1562 C>T polymorphism in the promoter region of MMP9. Diabetic wounds also showed a significant unmethylated status of MMP9 promoter compared to control wounds. In conclusion, The risk genotypes of -1562 C>T polymorphism along with lack of methylation of CpG sites in MMP9 gene promoter may result in altered expression of MMP9 in wounds of T2DM cases resulting into nonhealing chronic ulcers in them.