PPAR Signaling Maintains Metabolic Homeostasis under Hypothermia in Freshwater Drum (Aplodinotus grunniens)

Abstract

Aplodinotus grunniens, known as freshwater drum, is a kind of eurythermal freshwater fish that is widely distributed in North America. In 2019, our research group reached a milestone on its artificial breeding and cultivation and have investigated its physiological adaption to the environment, providing a breakthrough and prospects for aquaculture. However, its adaptability and metabolic homeostasis to hypothermia is not fully understood. In this experiment, cold stress was conducted at 18 °C (LT18) and 10 °C (LT10) with 25 °C as control (Con) for 8 days to explore the effects of short-term hypothermia on the physiology and metabolism of freshwater drum. From the results, the level of free essential amino acids in LT18 and LT10 decreased significantly after 2 days cold stress compared with Con. Furthermore, plasma total triglyceride (TG) content and lipase (LPS) activity were decreased at LT10 for 2d. With RNA-seq in the liver, metabolic-related signaling, especially amino acid synthesis and lipid metabolism, was inhibited by hypothermia. Specifically, the PPAR signaling pathway is correlated with the inhibition of lipid and amino acid metabolism induced by hypothermia. These data confirmed that PPAR signaling maintains lipid and amino acid metabolic homeostasis during cold stress. These results give a theoretical foundation for hypothermia resistance in the area of metabolic homeostasis for freshwater drum.

Fetal Hypoglycemia Induced by Placental SLC2A3-RNA Interference Alters Fetal Pancreas Development and Transcriptome at Mid-Gestation

“…FFA uptake, storage, and oxidation can also be regulated by binding to PPARs within the cell [33]. PPAR signaling also maintains lipid metabolic homeostasis during cold stress with reduced plasma glucose concentrations in fish [34].…”

Untargeted Metabolome Analyses Revealed Potential Metabolic Mechanisms of Leymus chinensis in Response to Simulated Animal Feeding

“…Moreover, animal saliva can affect the growth through the saliva-specific group. For example, the PPAR signaling pathway has been found to maintain lipid and amino acid metabolism homeostasis during cold stress [ 34 ]. Therefore, it can be speculated that animal saliva may maintain the growth of L. chinensis by maintaining cellular lipid and amino acid metabolism homeostasis.…”

Peroxisome Proliferator-Activated Receptor Signaling-Mediated 13-S-Hydroxyoctadecenoic Acid Is Involved in Lipid Metabolic Disorder and Oxidative Stress in the Liver of Freshwater Drum, Aplodinotus grunniens

“…As a regulator, PPAR controls the expression of a series of genes involved in lipid and lipoprotein metabolism [ 76 ]. In addition, our previous study found that PPAR signaling is implicated in the metabolic homeostasis of lipids and amino acids in freshwater drum with hypothermia [ 48 ]. PPARs are activated under starvation stress to regulate the expression of downstream adipose catabolism genes [ 77 ].…”

“…In light of these prospects, we imported freshwater drum larvae and achieved a worldwide breakthrough in advanced research on artificial breeding, feeding, and domestication. In 2022, we achieved large-scale fry breeding, laying the groundwork for the industrialized development of freshwater drum culture and the breeding of new varieties [ 45 , 46 , 47 , 48 , 49 ]. However, in the practical aquaculture, we found freshwater drum was susceptive to lipid deposition in the liver, which adversely affected the health of the freshwater drum.…”