👤 Mathilakath M Vijayan

Although fish exposed to municipal wastewater effluents (MWWE) show higher lipid accumulation, whether this is due to adipogenesis is unclear. The objective here was to identify molecular markers of adipogenesis in zebrafish (Danio rerio) larvae for use as high throughput screening tools for environmental contaminants, including obesogens in MWWE. Zebrafish larvae were fed a commercial diet at a maintenance level (5 % body mass) or in excess (25 or 50 % body mass) from day 6 to 30 days post-fertilization (dpf) to stimulate adipogenesis. We monitored fat accumulation and markers of lipid metabolism, including peroxisome proliferator-activated receptor γ (ppar γ), fatty acid synthase (fas), ELOVL fatty acid elongase 2 (elovl2), diacylglycerol O-acyltransferase 2 (dgat2), leptin (lepa and lepb), leptin receptor (lepr), and lipoprotein lipase (lpl). Excess feeding led to a higher growth rate, protein content and an increase in igf1 transcript abundance. Also, these larvae had higher triglyceride levels and accumulated lipids droplets in the abdominal cavity and viscera. The molecular markers of adipogenesis, including fas, elovl2, and dgat2, were upregulated, while the transcript abundance of lpl, a lipolytic gene, was transiently lower due to excess feeding. The increased adiposity seen at 30 dpf due to excess feeding coincided with a lower lep but not lepr transcript abundance in zebrafish. Our results demonstrate that excess feeding alters the developmental programming of key genes involved in lipid homeostasis, leading to excess lipid accumulation in zebrafish larvae. Overall, fas, elovl2, lpl, and dgat2, but not lep or ppar γ, have the potential to be biomarkers of adipogenesis in zebrafish larvae. Show less

Nonsyndromic cleft lip with or without cleft palate (NSCL±P) is a common craniofacial anomaly with multifactorial etiology. Evidence suggests that variations in WNT pathway genes contribute to an increased susceptibility to NSCL±P. The aim of this study was to investigate the association of AXIN1, APC, CTNNB1, DVL2, and GSK3β gene variants with NSCL±P in a case-control data set from Brazil. 471 individuals with NSCL±P and 504 unrelated control individuals of Caucasian ethnicity. Twenty single-nucleotide polymorphisms (SNPs) in/nearby AXIN1, APC, CTNNB1, DVL2, and GSK3B genes were genotyped using Taqman chemistry in a Viia7 sequence detection instrument. Genotype, allele, and haplotype frequencies were compared among NSCL±P patients and controls using Fisher exact test, implemented in PLINK software. The level of significance was established at P ≤.002 under Bonferroni correction. In silico analysis of SNP function was assessed using MirSNP database. Significant association was found between GSK3B rs13314595 genotypes and NSCL±P ( P = .0006). Additionally, nominal associations were found between DVL2 (rs35594616) and APC (rs448475) with NSCL±P ( P = .02 and P = .03, respectively). SNP haplotypes for GSK3B and APC genes showed nominal associations with NSCL±P ( P < .05). In silico analysis predicted that APC rs448475 harbors a binding site for the microRNA miR-617 and that the switch from a G allele to C allele enhances binding, whereas DVL2 rs35594616 did not appear to harbor microRNA-binding sites. This study shows for the first time the association between GSK3B and NSCL±P and confirms the role of additional WNT pathway genes as candidates for NSCL±P. Show less