Sirtuin 3 Restores Synthesis and Secretion of Very Low-Density Lipoproteins in Cow Hepatocytes Challenged with Nonesterified Fatty Acids In Vitro.

Dongmei Xing,Tao Peng,Jianhua He,Hongyu Lei,Hong Lu,Baogen Wang,Yingfang Zhou,Lei Liu,Jianming Su

doi:10.3390/vetsci8070121

Dongmei Xing, Tao Peng + Show 7 more

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https://doi.org/10.3390/vetsci8070121

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Journal: Veterinary sciences	Publication Date: Jun 30, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Hunan Agricultural University

Abstract

Fatty liver is closely associated with elevated concentrations of nonesterified fatty acids (NEFA) and a low level of very low-density lipoproteins (VLDL) in blood of dairy cows. High NEFA inhibit the VLDL synthesis and assembly, and cause hepatic triacylglycerol (TAG) deposition. Sirtuin 3 (SIRT3), a mitochondrial deacetylase, antagonizes NEFA-induced TAG accumulation through modulating expressions of fatty acid synthesis and oxidation genes in cow hepatocytes. However, the role of SIRT3 in the VLDL synthesis and assembly was largely unknown. Here we aimed to test whether SIRT3 would recover the synthesis and assembly of VLDL in cow hepatocytes induced by high NEFA. Primary cow hepatocytes were isolated from 3 Holstein cows. Hepatocytes were infected with SIRT3 overexpression adenovirus (Ad-SIRT3), SIRT3-short interfering (si) RNA, or first infected with Ad-SIRT3 and then incubated with 1.0 mM NEFA (Ad-SIRT3 + NEFA). Expressions of key genes in VLDL synthesis and the VLDL contents in cell culture supernatants were measured. SIRT3 overexpression significantly increased the mRNA abundance of microsomal triglyceride transfer protein (MTP), apolipoprotein B100 (ApoB100) and ApoE (p < 0.01), and raised VLDL contents in the supernatants (p < 0.01). However, SIRT3 silencing displayed a reverse effect in comparison to SIRT3 overexpression. Compared with NEFA treatment alone, the Ad-SIRT3 + NEFA significantly upregulated the mRNA abundance of MTP, ApoB100 and ApoE (p < 0.01), and increased VLDL contents in the supernatants (p < 0.01). Our data demonstrated that SIRT3 restored the synthesis and assembly of VLDL in cow hepatocytes challenged with NEFA, providing an in vitro basis for further investigations testing its feasibility against hepatic TAG accumulation in dairy cows during the perinatal period.

Highlights

apolipoprotein B100 (ApoB100) displayed of Sirtuin 3 (SIRT3) on the synthesis andof secretion of very low-density lipoproteins (VLDL)
InfectionFigure upon Ad-SIRT3 infection with multiplicity of infection (MOI) 100 the highest
Results are representative of dance of microsomal triglyceride transfer protein (MTP) (A), ApoB (B), and ApoE (C) were measured by Quantitative Reverse-Transcription PCR (qRT-PCR)

Summary

Introduction

Fatty liver is one of the most destructive metabolic diseases in dairy cows [1]. It is defined by the excessive accumulation of triacylglycerol (TAG) in the liver, and is related to declined health status, productivity, and reproductive performance [2]. Fatty liver can be further classified into three categories based on the liver TAG levels, i.e., mild fatty liver (1–5% liver TAG, % wet weight), moderate fatty liver (5–10% liver TAG), and severe fatty liver (>10% liver TAG) [3]. The incidence of fatty liver is high globally, ranging from 20%. To 65% for moderate fatty liver and 5% to 20% for severe fatty liver [3]. The mortality rate of fatty liver cases is high because of lack of effective therapy [4]

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