Zn Stimulates the Phospholipids Biosynthesis via the Pathways of Oxidative and Endoplasmic Reticulum Stress in the Intestine of Freshwater Teleost Yellow Catfish

Abstract

The hypothesis of our study was that waterborne Zn exposure evoked phospholipids (PL) biosynthesis to compensate for the loss of membrane integrity, and the pathways of oxidative stress and endoplasmic reticulum (ER) stress mediated the Zn-evoked changes of PL biosynthesis. Thus, we conducted RNA sequencing to analyze the differences in the intestinal transcriptomes between the control and Zn-treated P. fulvidraco. The 56-day Zn exposure increased the intestinal Zn accumulation, and mRNA levels of 816 genes were markedly up-regulated, while that of 263 genes were down-regulated. Many differentially expressed genes in the pathways of PL biosynthesis and protein processing in ER were identified. Their expression profiles indicated that waterborne Zn exposure injured protein metabolism, induced PL biosynthesis caused oxidative stress and ER stress, and activated the unfolded protein response. Then, using the primary enterocytes, we identified the mechanism of oxidative and ER stress mediating Zn-induced PL biosynthesis, and indicated that the activation of these pathways constituted adaptive mechanisms to reduce Zn toxicity. Our study demonstrated that Zn exposure via the water increased Zn accumulation and PL biosynthesis, and that oxidative stress and ER stress were interdependent and mediated the Zn-induced PL biosynthesis of the intestine in the freshwater teleost.

Nano-Zn Increased Zn Accumulation and Triglyceride Content by Up-Regulating Lipogenesis in Freshwater Teleost, Yellow Catfish Pelteobagrus fulvidraco

“…Intestinal epithelial cells were isolated from yellow catfish based on the methods of our previous studies [4,37]. Nano-Zn was dissolved in ultra-pure water at 10 mM stock concentrations and then sterilized.…”

“…To determine the mechanism of nano-Zn influencing lipogenesis, chlorpromazine (10 µg/mL), TPEN (Zn 2+ chelator, Sigma, MO, USA), and T0070907 (PPARγ inhibitor, Selleck, TX, USA) were used. The concentrations of inhibitors were selected according to our previous studies [4,37]. The primary intestinal epithelial cells from P. fulvidraco were incubated for 24 h in control or 40 µM nano-Zn containing medium with or without 2 h of pretreatment inhibitors.…”

“…The MTT assay was performed to test the cell viability according to our recent protocols [37]. TG content was analyzed by using the glycerol 3-phosphate oxidase p-aminophenol method.…”

“…The analysis of gene transcription levels was based on our recent publication [36,37]. The primers are given in Supplemental Table S2.…”

Influence of dietary zinc on growth, zinc bioaccumulation and expression of genes involved in antioxidant and innate immune in juvenile mud crabs (Scylla paramamosain)

“…Zn is a fundamental microelement that can stabilise cellular membranes and components in organs and tissues (14) . Specifically, it is an essential cofactor for numerous enzymes and proteins involved in many physiological processes including nucleic acid, protein, fatty acid, phospholipid and carbohydrate metabolism that are critical to growth, reproduction and development of aquatic animals (15)(16)(17) . In addition, Zn has key roles in antioxidant defence and immune response partly as an integral constituent of Zn-dependent metalloenzymes such as Cu/Zn superoxide dismutase (Cu/Zn SOD) and alkaline phosphatase (AKP) (18,19) and so inhibits free-radicalinduced oxidative damage to cells and tissues and supports immune functions by interacting with minerals such as Se, Cu and Mg and several other metalloenzymes (20) .…”