Vitamin D deficiency serves as a precursor to stunted growth and central adiposity in zebrafish

Abstract

Emerging evidence demonstrates the importance of sufficient vitamin D (1α, 25-dihydroxyvitamin D3) levels during early life stage development with deficiencies associated with long-term effects into adulthood. While vitamin D has traditionally been associated with mineral ion homeostasis, accumulating evidence suggests non-calcemic roles for vitamin D including metabolic homeostasis. In this study, we examined the hypothesis that vitamin D deficiency (VDD) during early life stage development precedes metabolic disruption. Three dietary cohorts of zebrafish were placed on engineered diets including a standard laboratory control diet, a vitamin D null diet, and a vitamin D enriched diet. Zebrafish grown on a vitamin D null diet between 2–12 months post fertilization (mpf) exhibited diminished somatic growth and enhanced central adiposity associated with accumulation and enlargement of visceral and subcutaneous adipose depots indicative of both adipocyte hypertrophy and hyperplasia. VDD zebrafish exhibited elevated hepatic triglycerides, attenuated plasma free fatty acids and attenuated lipoprotein lipase activity consistent with hallmarks of dyslipidemia. VDD induced dysregulation of gene networks associated with growth hormone and insulin signaling, including induction of suppressor of cytokine signaling. These findings indicate that early developmental VDD impacts metabolic health by disrupting the balance between somatic growth and adipose accumulation.

Vitamin D deficiency promotes accumulation of bioactive lipids and increased endocannabinoid tone in zebrafish

“…We chose to focus our investigation on putative identification of ions more abundant in the VDD fish compared to the VDS fish given the robust fatty phenotype we previously published. 35 Ultimately, we found that VDD zebrafish had a greater abundance of bioactive lipids compared to VDS zebrafish, suggestive of increased endocannabinoid tone.…”

“…All zebrafish were maintained as previously described, according to protocols approved by the North Carolina State University Institutional Animal Care and Use Committee. 35 Adult zebrafish were maintained at appropriate densities in 9L tanks as part of a recirculating aquatics system under a 14:10 h light:dark cycle. Water temperature was maintained at 28.5 ± 0.5 °C with a pH between 6.8 and 7.5.…”

“…Dietary cohorts were generated as previously described with a few modifications. 35 To generate F0 cohorts, ABxAB zebrafish were raised on a standard larval laboratory diet (11.5 iu/g VD) until two months of age. At the two-month time point, juvenile zebrafish were assessed for standard length to determine the average SL for the population, and any fish ±2 standard deviations away from the mean were removed from the cohort.…”

“…qPCR Quantitative Real-Time PCR (qPCR) was used to measure targeted gene expression in male zebrafish liver and AT at 6 mpf as previously described. 35 cDNA was synthesized from total RNA using 10x random primers, 10x reverse transcription buffer, MultiScribe Reverse Transcriptase, and 10mM deoxynucleotide triphosphates from a High Capacity cDNA Reverse Transcription Kit (Applied Biosystems, Foster City, CA) along with RNasin(R) RNase Inhibitor (Promega, Madison, WI). Primer sequences were designed using Primer3web, version 4.1.0.…”

“…31,32,33,34 Previously our lab established a linkage between VDD and metabolic dyshomeostasis, where low levels of vitamin D resulted in stunted growth and central adiposity in zebrafish by 6 months post fertilization (mpf). 35 The purpose of the study presented herein was to further investigate this linkage using a spatial lipidomics approach and identify putative differences in untargeted lipid metabolites between VDD and VDS zebrafish at 6mpf. Infrared-matrix-assisted laser desorption electrospray ionization mass spectrometry imaging (IR-MALDESI-MSI) was used to determine altered lipid metabolite profiles, spatial distributions, and abundance between VDD and VDS in whole sectioned zebrafish.…”