👤 Karunaianantham Ramesh

Hereditary Multiple Osteochondromas (HMO) is a rare, pediatric skeletal disorder characterized by osteochondromas that form along the growth plates. These benign tumors can cause skeletal deformities, joint dysfunction, chronic pain and other health problems. Most HMO patients are born with a heterozygous mutation in EXT1 or EXT2 that encode Golgi enzymes responsible for heparan sulfate synthesis. However, prior studies have established that these mutations alone are insufficient to trigger osteochondroma formation, but additional genetic changes are needed. Loss-of-heterozygosity (LOH) has been invoked in some cases, but the full genomic landscape of osteochondromas remains unclear. Here, we carried out a proof-of-principle study and asked whether gene variants occur in osteochondromas in addition to EXT mutations, whether the variants are shared by osteochondromas in same or different patients and what putative pathogenic roles they may have. A total of 8 tumors from 4 patients were subjected to whole exome sequencing (WES) along with saliva DNA from the 4 patients and 3 parents that was used as specific reference. WES identified over 1,600 somatic single nucleotide variants or insertion/deletions that were only partially shared amongst the tumors and were absent in the saliva DNA. Six genes were commonly mutated, including PABC1, TDG and ANKRD36. These genes exert action which could directly or indirectly influence chondrogenesis, the first differentiation step in osteochondroma formation. The study reveals that osteochondromas do possess gene variants distinguishing them in the same or different patients. These traits could modulate their tumorigenic character and add complexity to HMO pathogenesis. Clinical Significance: This study provides insights into the genomic landscape of osteochondromas, potentially leading to development of disease diagnostic and prognostic tools. Show less

Osteochondromas characterize the rare pediatric disorder hereditary multiple osteochondromas (HMO). The tumors originate from the growth plate perichondrium along skeletal elements, appear first as ectopic cartilage, and then grow unidirectionally, colliding with and damaging surrounding structures. HMO is caused by mutations that affect the heparan sulfate (HS) synthases EXT1 or EXT2, leading to HS deficiency and aberrant activity of HS-binding growth factors. We investigated the signaling pathways and mechanisms underlying tumor growth in HMO using mice with conditional Show less

Sterubin (7-O-Methyleriodicytol), a flavanone compound isolated from the leaves of Eriodicyton californicum and Eriodicyton angustifolium, has neuroprotective, anti-inflammatory, and antioxidant properties. Therefore, it is of interest to identify the potential targets for Alzheimer disease using network pharmacology. We report 25 overlapping targets among 100 potential targets of sterubin and 673 known targets of Alzheimer. APP, BACE-1, and AChE were among the ten hub targets enriched in biological processes and pathways relevant to Alzheimer's disease. Subsequent, molecular docking analysis shows that sterubin have optimal binding features with these hub gene targets for further consideration. Show less

Flavonoids are promising therapeutics for the treatment of Alzheimer's disease (AD). Therefore, it is of interest to study the anti-AD potential of 35 flavonoids towards the inhibition of AchE and BACE-1. Hence, the physicochemical, pharmacokinetic parameters, toxicity risk and drug-likeliness of the selected 35 flavonoids were computed. Further, the molecular docking analysis of flavonoids with AChE and BACE-1 were completed. A binding energy of -10.42 kcal/mol Epicatechin gallate, -10.16 kcal/mol sterubin and -10.11 kcal/mol Fisetin was observed with AchE as potential inhibitors. Similarly, Biochainin-A -9.81kcal/mol, Sterubin -8.96 kcal/mol and Epicatechin gallate -7.4 7 kcal/mol showed with BACE-1. Thus, these flavonoids are potential leads for structure-based design of effective anti-Alzheimer's agents. Show less

Obesity is one of the more complicated diseases, it can induce numerous life-threatening diseases mainly diabetes mellitus, cardiovascular disease, hypertension, and certain cancers. In this study, we assessed the efficacy of bacoside-A (a dammarane-type triterpenoid saponin derived from the plant Bacopa monniera Linn.) on the adipogenesis of 3T3-L1 preadipocytes. Results of this study illustrated that bacoside-A decreased the differentiation of 3T3-L1 cell, as evidenced by diminution of lipid droplets, which contains triglycerides and other lipids. During the differentiation process, transcription factors, which are mainly participating in adipogenesis such us CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPβ, peroxisome proliferator-activated receptor-γ (PPARγ), and sterol regulatory element-binding protein-1c (SREBP-1c), expressions were significantly suppressed by bacoside-A. In addition, bacoside-A showed a potent reduction in genes precise to adipocytes such as lipoprotein lipase (LPL), fatty acid synthase (FAS), adipocyte fatty acid-binding protein (FABP4), and leptin expressions. Further, bacoside-A stimulated the phosphorylation of acetyl CoA carboxylase (ACC) and AMP-activated protein kinase (AMPK). These results demonstrated that bacoside-A has anti-adipogenic effects by regulating the transcription factors involved in adipocyte differentiation. Therefore, bacoside-A might be considered as a potent therapeutic agent for alleviating obesity and hyperlipidemia. Show less

Children exposed to antiretroviral therapy (ART) are at risk of developing metabolic complications. The association between gene polymorphisms and the development of dyslipidemia in children post ART initiation was studied. Children initiating first-line ART were followed for 2 years at the National Institute for Research in Tuberculosis (Chennai, India), and St. John's Medical College Hospital (Bangalore, India). Clinical examination and fasting serum lipid profiles were measured every 6 months. Participants were genotyped for the polymorphisms in the APOC3 gene (rs2854116; rs2854117, and rs5128). Changes in lipid levels from baseline to months 6, 12, and 24, and the difference between the various genotype variants were analyzed using a modified analysis of variance test. Study enrolled 393 ART-naive HIV-infected children (mean age: 7.6 ± 3 years, mean weight: 18 ± 6) of whom 289 (75%) were started on nevirapine (NVP)-based ART and the remaining 96 (25%) were started on efavirenz-based ART. Only children carrying the GG allele of rs5128 genotype showed a decrease in CD4% and serum triglycerides pre-ART. An increasing trend of total cholesterol, high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol were seen at 6 months in both EFZ and NVP groups, which subsequently stabilized by 12 months irrespective of genotype variants. Genotype variants of APOC3 (rs2854116 and rs2854117 polymorphism) did not show significant changes in serum lipid levels after 24 months of ART, whereas rs5128 polymorphism with "G" allele showed an association with HDL-c levels when on NVP-based ART. Our results suggest that ART plays a major role in normalizing lipid levels in HIV-infected children and APOC3 polymorphisms may not play a significant role in ART-induced dyslipidemia. Show less

Cardiovascular disease (CVD) risk with low high-density lipoprotein cholesterol (HDL-C) and high triglycerides is common in the general population in India. As nevirapine (NVP)-based antiretroviral therapy (ART) tends to increase HDL-C, gene polymorphisms associated with HDL-C metabolism in HIV-infected adults on stable NVP-based ART were studied. A cross-sectional study was conducted between January 2013 and July 2014 among adults receiving NVP-based ART for 12-15 months. Blood lipids were estimated and gene polymorphisms in apolipoprotein C3 (APOC3), cholesteryl ester transfer protein (CETP) and lipoprotein lipase (LPL) genes were analyzed by real-time polymerase chain reaction. Framingham's 10-yr CVD risk score was estimated. Logistic regression was done to show factors related to low HDL-C levels. Of the 300 patients included (mean age: 38.6±8.7 yr; mean CD4 count 449±210 cell/μl), total cholesterol (TC) >200 mg/dl was observed in 116 (39%) patients. Thirty nine per cent males and 47 per cent females had HDL-C levels below normal while 32 per cent males and 37 per cent females had TC/HDL ratio of 4.5 and 4.0, respectively. Body mass index [adjusted odds ratio (aOR)=1.70, 95% confidence interval (CI) 1.01-2.84, P=0.04] and viral load (aOR=3.39, 95% CI: 1.52-7.52, P=0.003) were negatively associated with serum HDL-C levels. The 10-yr risk score of developing CVD was 11-20 per cent in 3 per cent patients. Allelic variants of APOC3 showed a trend towards low HDL-C. High-risk lipid profiles for atherosclerosis and cardiovascular disease were common among HIV-infected individuals, even after 12 months of NVP-based ART. Targeted interventions to address these factors should be recommended in the national ART programmes. Show less

We report cytogenetic findings in a case of grade III chondrosarcoma. Complex clonal chromosome aberrations including monosomy of chromosomes 4, 8, 13, and a consistent t(5;14)(q23;p12) were observed in all cells. There were no structural or numerical anomalies involving chromosome 12. The complexity of the chromosome aberrations reflect the advanced stage of this chondrosarcoma; we suggest a possible involvement of the EXT1 gene located on chromosome 8. Show less