Association of polymorphism in heat shock protein 70 genes with type 2 diabetes in Bangladeshi population

Heat shock protein 70 gene polymorphisms in Iranian patients with Multiple sclerosis

Genetic factors are effective reagents in susceptibility to multiple sclerosis (MS). Previous studies have shown the relationship between heat shock protein (HSP) gene polymorphisms. So, HSP70 single nucleotide polymorphisms (SNPs) were evaluated as MS risk factors. Here, DNA genotyping was done for HSP70 gene polymorphisms, including HSP70-1 +190 G>C, HSP70-1 -110 A>C, HSP70-1 +438 A>C, and HSP70-hom +2437 A>G in two groups including Iranian MS patients and controls. A standard phenol/chloroform method isolated DNA samples from peripheral blood. Sequence-specific amplification (SSP) polymerase chain reaction (PCR) was used for genotyping polymorphisms. Overall, 76 (35.80%) MS patients and 136 (65.10%) controls were studied with an age mean of 36.0 ± 8.0 years. Female/male was significantly higher in patients than in controls (4.43 vs. 0.10, P < 0.001). The average age was significantly lower in patients (P < 0.001). The most common clinical feature was relapsing-remitting (RR) MS; more than half of the population was Fars. Results showed that genotypes of HSP70-hom +2437 C>T had a significant relation with MS (OR = 2.0, 95% CI = 1.0-5.0, P = 0.03) and the same applies to HSP70-1 -110 A>C (OR = 0.0, 95% CI = 0.0-1.0, P < 0.001). Allele and genotype frequency of two other HSP70 SNPs (HSP70-1 +190 G>C, HSP70-1 +438 A>C) showed no significant differences between patients and controls. HSP70-hom +2437 C>T and HSP70-1 -110 A>C can be considered as risk factors for MS in our population. However, other HSP SNPs should be studied in a larger population in the future.

Genetic Analysis of HSP70 and HSF3 Polymorphisms and Their Associations with the Egg Production Traits of Bangladeshi Hilly Chickens

In warm environments, thermoregulation in poultry is controlled by heat shock protein 70 (HSP70), whose expression is controlled by heat shock factor 3 (HSF3). Although the association between genetic polymorphisms in these genes and thermotolerance as well as reproductive traits has been extensively studied in mammals, the association has not yet been studied in poultry. This study aimed to explore the relationship between single-nucleotide polymorphisms (SNPs) in these genes and the egg production traits of Bangladeshi hilly chickens. Sequencing and allele-specific PCR (AS-PCR) were used to detect new SNPs and perform genotyping. We identified two novel SNPs (G-399A and A-68G) in the 5'-flanking regions of HSP70 that were significantly associated with egg numbers (ENs) at 161-190 days and increased egg weight (EW) at 40 weeks of age. Furthermore, three SNPs in HSP70 (A258G, C276G and C1431A) and one SNP in HSF3 (A-1388G) were associated with EN at different ages. The haplotype and combined genotypic effects of these two genes were found to be associated with age at sexual maturity (ASM), EN, EW, and body weight at ASM. The identified SNPs and their corresponding haplotypes may be useful in selective breeding to enhance the productivity of chickens in warm environments.

The role of heat shock proteins (HSPs) in type 2 diabetes mellitus pathophysiology

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by sustained hyperglycemia caused by impaired insulin signaling and secretion. Metabolic stress, caused by an inappropriate diet, is one of the major hallmarks provoking inflammation, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction. Heat shock proteins (HSPs) are a group of highly conserved proteins that have a crucial role in chaperoning damaged and misfolded proteins to avoid disruption of cellular homeostasis under stress conditions. To do this, HSPs interact with diverse intra-and extracellular pathways among which are the insulin signaling, insulin secretion, and apoptosis pathways. Therefore, HSP dysfunction, e.g. HSP70, may lead to disruption of the pathways responsible for insulin secretion and uptake. Consistently, the altered expression of other HSPs and genetic polymorphisms in HSP-producing genes in diabetic subjects has made HSPs hot research in T2DM. This paper provides a comprehensive overview of the role of different HSPs in T2DM pathogenesis, affected cellular pathways, and the potential therapeutic strategies targeting HSPs in T2DM.

A Polymorphism in the Gene Encoding Heat Shock Factor 1 (HSF1) Increases the Risk of Type 2 Diabetes: A Pilot Study Supports a Role for Impaired Protein Folding in Disease Pathogenesis

The aim of this pilot study was to investigate whether polymorphisms in the gene encoding heat shock factor 1 (HSF1), a transcriptional activator of molecular chaperones, play a role in the development of type 2 diabetes (T2D). A total of 3229 unrelated individuals of Slavic origin, including 1569 T2D patients and 1660 age- and sex-matched healthy controls, were enrolled for the study. Five common single nucleotide polymorphisms (SNPs) of the HSF1 gene were genotyped using the MassArray-4 system. SNPs rs7838717 (p = 0.002) and rs3757971 (p = 0.005) showed an association with an increased risk of T2D in females with a body mass index ≥ 25 kg/m². The rs7838717T-rs4279640T-rs3757971C and rs7838717T-rs4279640T-rs3757971T haplotypes were associated with increased and decreased disease risk in overweight or obese females, respectively. The associations were replicated as disease susceptibility genes in large cohorts from the UK Biobank (p = 0.008), DIAMANTE (p = 2.7 × 10^-13), and DIAGRAM (p = 0.0004) consortiums. The functional annotation of the SNPs revealed that the rs7838717-T and rs3757971C alleles correlated with increased expression of the genes involved in unfolded protein response. The present study showed, for the first time, that genetic variation of HSF1 is associated with the risk of type 2 diabetes, supporting a role for impaired protein folding in disease pathogenesis.

High-Risk Polymorphisms Associated with the Molecular Function of Human HMGCR Gene Infer the Inhibition of Cholesterol Biosynthesis

HMG-CoA reductase or HMGCR (3-hydroxy-3-methylglutaryl-CoA reductase) is a rate-limiting enzyme involved in cholesterol biosynthesis. HMGCR plays an important role in the possible occurrence of hypercholesterolemia leading to atherosclerosis and coronary heart disease. This enzyme is a major target for cholesterol-lowering drugs such as "statin" which blocks the synthesis of mevalonate, a precursor for cholesterol biosynthesis. This study is aimed at characterizing deleterious mutations and classifying functional single nucleotide polymorphisms (SNPs) of the HMGCR gene through analysis of functional and structural evaluation, domain association, solvent accessibility, and energy minimization studies. The functional and characterization tools such as SIFT, PolyPhen, SNPs and GO, Panther, I-Mutant, and Pfam along with programming were employed to explore all the available SNPs in the HMGCR gene in the database. Among 6815 SNP entries from different databases, approximately 388 SNPs were found to be missense. Analysis showed that seven missense SNPs are more likely to have deleterious effects. A tertiary model of the mutant protein was constructed to determine the functional and structural effects of the HMGCR mutation. In addition, the location of the mutations suggests that they may have deleterious effects because most of the mutations are residing in the functional domain of the protein. The findings from the analysis predicted that rs147043821 and rs193026499 missense SNPs could cause significant structural and functional instability in the mutated proteins of the HMGCR gene. The findings of the current study will likely be useful in future efforts to uncover the mechanism and cause of hypercholesterolemia. In addition, the identified SNPs of HMGCR gene could set up a strong foundation for further therapeutic discovery.

Association of polymorphism in heat shock protein 70 genes with type 2 diabetes in Bangladeshi population

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic disorder of which stress is a major contributor. Under stressful condition, body synthesizes a family of molecular chaperone called Heat-shock proteins (HSPs). Current study assessed the frequency and association of HSP70-hom + 2,437 T/C polymorphism with T2DM risk among Bangladeshis.

METHODS

This polymorphism was selected through bioinformatics analyses and identified by PCR-RFLP method.

RESULTS

Bioinformatics analysis identified this SNP as missense mutation which could destabilize the final HSP product. Heterozygous mutant (CT) genotype was significantly associated with T2DM incidence among the studied populations (p = .015). Further analysis revealed a strong association with female patients (p = .002), while the male group showed no association (p = .958). Moreover, the C allele was significantly associated among all diabetic patients (p = .016) and particularly in the female patient group (p = .001). However, under stressful condition, males with CT genotype were at high risk for T2DM incidence whereas, females with CT genotype showed no significant association.

CONCLUSIONS

HSP70-hom + 2,437 T/C polymorphism was found to be significantly associated with T2DM incidence in the Bangladeshi population in both stress-dependent and independent manners.