Whole exome sequencing identifies novel variants of PIK3CA and validation of hotspot mutation by droplet digital PCR in breast cancer among Indian population.

BACKGROUND: Breast cancer (BC) is the most common malignancy with very high incidence and relatively high mortality in women. The PIK3CA gene plays a pivotal role in the pathogenicity of breast cancer. Despite this, the mutational status of all exons except exons 9 and 20 still remains unknown. METHODS: This study uses the whole exome sequencing (WES) based approach to identify somatic PIK3CA mutations in Indian BC cohorts. The resultant hotspot mutations were validated by droplet digital PCR (ddPCR). Further, molecular dynamics (MD) simulation was applied to elucidate the conformational and functional effects of hotspot position on PIK3CA protein. RESULTS: In our cohort, PIK3CA showed a 44.4% somatic mutation rate and was among the top mutated genes. The mutations of PIK3CA were confined in Exons 5, 9, 11, 18, and 20, whereas the maximum number of mutations lies within exons 9 and 20. A total of 9 variants were found in our study, of which 2 were novel mutations observed on exons 9 (p.H554L) and 11 (p.S629P). However, H1047R was the hotspot mutation at exon 20 (20%). In tumor tissues, there was a considerable difference between copy number of wild-type and H1047R mutant was detected by ddPCR. Significant structural and conformational changes were observed during MD simulation, induced due to point mutation at H1047R/L position. CONCLUSIONS: The current study provides a comprehensive view of novel as well as reported single nucleotide variants (SNVs) in PIK3CA gene associated with Indian breast cancer cases. The mutation status of H1047R/L could serve as a prognostic value in terms of selecting targeted therapy in BC.

Comprehensive mutations analyses of FTO (fat mass and obesity-associated gene) and their effects on FTO's substrate binding implicated in obesity.

An excessive amount of fat deposition in the body leads to obesity which is a complex disease and poses a generic threat to human health. It increases the risk of various other diseases like diabetes, cardiovascular disease, and multiple types of cancer. Genomic studies have shown that the expression of the fat mass obesity (FTO) gene was highly altered and identified as one of the key biomarkers for obesity. This study has been undertaken to investigate the mutational profile of the FTO gene and elucidates its effect on the protein structure and function. Harmful effects of various missense mutations were predicted using different independent tools and it was observed that all mutations were highly pathogenic. Molecular dynamics (MD) simulations were performed to study the structure and function of FTO protein upon different mutations and it was found that mutations decreased the structure stability and affected protein conformation. Furthermore, a protein residue network analysis suggested that the mutations affected the overall residues bonding and topology. Finally, molecular docking coupled with MD simulation suggested that mutations affected FTO substrate binding by changing the protein-ligand affinity. Hence, the results of this finding would help in an in-depth understanding of the molecular biology of the FTO gene and its variants and lead to the development of effective therapeutics against associated diseases and disorders.

Association of ACE I/D gene polymorphism and related risk factors in impaired fasting glucose and type 2 diabetes: a study among two tribal populations of North-East India.

BACKGROUND: Type 2 diabetes is a serious public health concern in India, even the indigenous tribal populations are not left unaffected. The present study aims to understand the association of major risk factors i.e. obesity, hypertension, dyslipidemia, ACE I/D polymorphism with impaired fasting glucose (IFG) and type 2 diabetes (T2D) among two different Mendelian populations of North East India. METHODS: Demographic, somatometric, physiological variables along with fasting blood samples were collected from 609 individuals. The participants were screened for ACE I/D polymorphism. RESULTS: ACE I/D polymorphism was found to follow HWE among Liangmai tribe but not among Mizo tribe. Distribution of DD genotype/D allele was found to be significantly higher for T2D among Mizo tribe. Significant association were observed between DD genotype/D allele of ACE I/D polymorphism and TC as well as LDL with both IFG and T2D only in Mizo tribe. CONCLUSIONS: The present study is an example of gene-environment interaction where DD genotype or D allele and dyslipidemia (high TC and high LDL) are posing risk for IFG and T2D both independently and in combination only among Mizo tribe with relatively less physical activity attributed to their residence in less hilly terrain however Liangmai tribe which resides in high hilly terrain shows no such association.

Obesity, dyslipidaemia and candidate gene polymorphisms: a cross-sectional study among the Liangmai and Mizo tribes of Manipur, India.

BACKGROUND: The prevalence of obesity and dyslipidaemia was observed to be increased among the tribal populations, due to globalization. MATERIALS AND METHODS: In the present study, data on demographic, somatometric and blood samples were collected from 613 participants of both sex, age 18-60 years, further lipid profiling and genotyping was executed. Multifactor dimensionality reduction (MDR) software was used for gene-gene interactions analysis. RESULTS: Significantly differences were observed with respect to the general characteristic and selected gene polymorphisms in both the tribes. Among the Liangmai tribe, MC4R gene was found to pose significant decreased risk for waist-height ratio (WHtR) (OR = 0.56; 95% confidence interval (CI)= 0.32-0.99; p value = .04) and HDL (OR = 0.58; 95% CI = 0.36-0.92; p value = .02). Similar trends of significant decreased risk (OR = 0.39; 95% CI = 0.20-0.76; p value=.006) for BMI were observed among the Mizo tribe. The gene-gene interaction revealed the combined model of FTO+MC4R genes shows an increased risk for BMI in both the tribes. The independent significant increased risk posed by FTO gene was moderated by interaction with MC4R gene. CONCLUSIONS: The observed differences can possibly attribute to both their respective ancestries resulting in different gene pools and the physical environment. The results of the study highlight the importance of gene-gene and gene-environment interactions in adverse phenotype groups.KEY MESSAGEAmong the tribal population, the prevalence of obesity and dyslipidaemia has been increased.Differential distribution and associations of selected markers hint towards differential genetic architecture in these populations.MC4R rs17782313 polymorphism was found to show a significantly decreased risk for WHtR and low HDL among the Liangmai tribe and BMI among the Mizo tribe.Significant increased risk posed by FTO rs9939609 gene polymorphism was moderated by the interaction with MC4R rs17782313.

Mutant strains of SARS-CoV-2 are more prone to infect obese patient: a review.

The current review critically analyzes obesity as an important risk factor for increased predisposition towards coronavirus disease 2019 (COVID-19), its severity and causal death in current pandemic. Countries with higher prevalence of exposed obese individuals experienced the highest number of mortalities. The analysis also proved that individuals having more adipose tissue in body have a higher level of angiotensin-converting enzyme 2 (ACE2), which is identified as functional receptor for COVID-19. Therefore, obese individuals are worse in condition because of a higher presence of adiposity increases the number of ACE2 expressing cells. Furthermore, in silico interactions of ACE2 and different variants of coronavirus 2 (CoV-2) spike S1 protein suggest that mutant strains are more infectious than wildtype as they bind to host ACE2 protein with high binding affinities. Certain specific cancers including cervical cancer, pancreatic and rectal adenocarcinomas have more expression of such receptors and pose additional risk to already immunocompromised cancer patients. This review emphasizes obesity, as the covert risk factor of COVID-19 infection and sensitizes about of calorie restrictions, immunity building and preventive measures.

Genomic Heterogeneity of the Naga and Kuki Tribal Populations of Manipur, Northeast India.

Manipur, one of the northeastern states of India, lies on the ancient silk route and serves as a meeting point between Southeast Asia and South Asia. The origin and migration histories of Naga and Kuki tribal populations are not clearly understood. Moreover, Kukis have been traced to two different ancestries, which has created confusion among the people. The present study examined genomic affinities and differentiation of the Naga and Kuki tribal populations of Manipur, Northeast India. Twenty autosomal markers (8 Alu insertion-deletions, 12 restriction-fragment-length polymorphisms) were analyzed. Findings show genetic differences between Naga and Kuki tribal populations with respect to the allele distribution pattern, which was substantiated by genetic differentiation (GST = 5.2%) and molecular variance (AMOVA), where the highest percentage of among-group variances was observed between Naga and Kuki tribal groups (7.09%). However, genetic similarities with respect to allele distribution patterns in most of the loci were seen among their respective groups (Rongmei and Inpui, Thadou and Vaiphei). Rongmei and Inpui tribal populations (Naga group) belong to the Naga-Bodo linguistic group, and Thadou and Vaiphei (Kuki group) belong to the Northern Kuki-Chin linguistic group, suggesting that genetic similarities may not be independent of linguistic affinities. Despite differential genetic affinities, both Naga and Kuki tribal populations in Manipur show more proximity with Southeast Asian populations and Northeast Indian populations than with other Indian populations and global populations taken for comparison.

Prevalence of cardiovascular risk factors among tribal and non-tribal populations with East Asian Ancestry from North East India.

OBJECTIVES: The distribution of hypertension, type 2 diabetes, dyslipidemia, and obesity variables were studied among tribal and non-tribal populations with East Asian ancestry from northeast India. METHODS: Data pertaining to somatometric measurements, blood pressure, lipid profile, and fasting blood glucose were collected from 1916 participants (Mizo-422, Liangmai-352, and Meitei-1142) of both sexes older than 18 years. Two-way ANOVA and chi square analysis were done to understand the inter-population prevalence differences. RESULTS: Differential distribution of obesity variables, hypertension, type 2 diabetes, and dyslipidemia was observed among the three populations. CONCLUSIONS: Population-specific prevalence studies need to be conducted to develop population-specific health strategies, specifically in countries like India with huge diversity.

Differential distribution and association of FTO rs9939609 gene polymorphism with obesity: A cross-sectional study among two tribal populations of India with East-Asian ancestry.

The fat mass and obesity associated (FTO) rs9939609 gene polymorphism is most widely studied in terms of obesity in various populations. Recently, the prevalence of obesity has been reported to be very high among the North-Eastern State of India. The major aim of the present study is to understand the extent of FTO rs9939609 gene polymorphism and its association with obesity among the two North-East Indian tribal populations with similar East Asian ancestry. Somatometric data and fasting blood sample were collected from 521 tribal individuals (258 Liangmai and 263 Mizo) of Manipur after obtaining written informed consent. Genotyping of FTO rs9939609 single nucleotide polymorphism (SNP) was done using restriction fragment length polymorphism method for PCR-amplified fragments. Both the presently studied populations were not following Hardy-Weinberg law. The prevalence of obesity and minor allele frequency of FTO rs9939609 polymorphism was found to be significantly higher among the Mizo tribe compared to that of Liangmai. The selected polymorphism was found to be significantly associated with obesity (BMI) only among the Liangmai tribe (Odds ratio-3.0; 95% CI-1.4, 6.4; p-0.003), after adjusting for age and occupation. Age-cohort wise distribution and absolute fitness analysis indicated the lower fitness of minor allele in the higher age group among the Liangmai tribe. To the best of the author's knowledge this is the first study, associating FTO rs9939609 gene polymorphism and obesity in the North-eastern Indian tribal populations with East-Asian ancestry. This study revealed the FTO rs9939609 polymorphism is observed to be associated with obesity only among the Liangmai tribe not among the Mizo tribe. The differential distribution and association observed in the two selected tribes, inhabited in a similar geographical region, could be attributed to differences in their migratory histories in terms of both route and time of settlement.