2. Academic Validation
  3. Ovarian expression of functional MTTP and apoB for VLDL assembly and secretion in chickens

Ovarian expression of functional MTTP and apoB for VLDL assembly and secretion in chickens

  • Poult Sci. 2025 Mar 6;104(5):104993. doi: 10.1016/j.psj.2025.104993.
Yu-Hui Chen 1,  Petnamnueng Dettipponpong 2,  Mei-Ying Sin 3,  Ling-Chu Chang 3,  Chuen-Yu Cheng 4,  San-Yuan Huang 5,  Rosemary L Walzem 6,  Hsu-Chen Cheng 7,  Shuen-Ei Chen 8
Affiliations

Affiliations

  • 1 Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan; Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan.
  • 2 Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan.
  • 3 Center for Molecular Medicine, China Medical University Hospital, Taichung 404327, Taiwan; Research Center for Cancer Biology, China Medical University, Taichung 40402, Taiwan; Cancer Biology and Precision Therapeutics Center, China Medical University, Taichung 40402, Taiwan.
  • 4 Department of Animal Science and Biotechnology, Tunghai University, Taichung 407224, Taiwan.
  • 5 Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan; The iEGG and Animal Biotechnology Center and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 40227, Taiwan; i-Center for Advanced Science and Technology (iCAST), National Chung Hsing University, Taichung 40227, Taiwan.
  • 6 Department of Poultry Science, Texas A&M University, College Station, TX 77843, USA.
  • 7 Department of Life Sciences, National Chung Hsing University, Taichung 40227, Taiwan; i-Center for Advanced Science and Technology (iCAST), National Chung Hsing University, Taichung 40227, Taiwan. Electronic address: hcheng@dragon.nchu.edu.tw.
  • 8 Department of Animal Science, National Chung Hsing University, Taichung 40227, Taiwan; The iEGG and Animal Biotechnology Center and Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung 40227, Taiwan; i-Center for Advanced Science and Technology (iCAST), National Chung Hsing University, Taichung 40227, Taiwan. Electronic address: shueneic@dragon.nchu.edu.tw.
PMID: 40073639 DOI: 10.1016/j.psj.2025.104993
Abstract

In mammals, tissues Other than liver and intestine are known to possess functional MTTP (microsomal triglyceride transfer protein) and apoB (Apolipoprotein B) capable of VLDL (very low-density lipoprotein) assembly. Birds are oviparous and possess unique capabilities in lipid biology to accommodate yolk formation through massive deposition of hepatically assembled yolk-targeted VLDLy into ovarian follicles. Following identifications of MTTP and apoB expression within chicken ovarian stroma, granulosa, theca, and epithelial cells of various classes of follicles, we sought to define the functionality of ovarian MTTP and apoB in VLDL assembly. In situ hybridization analysis found that apoB transcripts are most abundant in thecal layers, whereas immunohistochemistry showed that MTTP predominates in the granulosa layers. MTTP lipid transfer activity was greater in small yellow follicles than in hierarchical follicles. Metabolic labeling, electron microscopy, and Western blot studies confirmed the functionality of ovarian apoB and MTTP as newly assembled VLDL around 50-200 nm in diameter and lacking ApoVLDL-II dissimilar to VLDLy, were secreted from cultured follicular cells. Lomitapide and the ApoB-antisense oligonucleotide Mipomersen dose-dependently decreased MTTP activity and VLDL-apoB secretion from cultured follicular cells, while oleate addition or acute heat stress enhanced VLDL-apoB secretion. Ultrastructural images showed VLDL assembly and trafficking toward the secretion route. The findings support the notion that VLDL assembly and secretion within avian ovarian tissues functions as a protective mechanism against fuel and physical stressors to secure follicle development and/or nutritional quality control of yolk for embryo development.

Keywords

Apolipoprotein B; Chickens; Microsomal triglyceride transfer protein; Ovary; VLDL secretion.

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