Function of HIF-1α in Regulating Sphingolipid Metabolism and Alleviating Oxidative Stress Damage in Callosobruchus chinensis Under Hypoxia

Abstract

Simple Summary Callosobruchus chinensis (Coleoptera: Bruchidae) is a typical stored-product insect that exhibits remarkable adaptability to hypoxic environments. Hypoxia-inducible factor 1α (HIF1α) is a key stress-responsive transcription factor in insects under low-oxygen conditions; however, its regulatory role in lipid metabolism remains poorly understood. This study, therefore, aimed to investigate the function of HIF1α in modulating lipid metabolism in C. chinensis. The full sequence of the CcHIF1α gene was cloned and characterized, revealing its highly conserved structure. After knockdown via interference (RNAi), insects showed higher mortality, decreased activities of typical antioxidant enzymes, and increased levels of reactive oxygen species (ROS) and lipid peroxidation products (LPO) under hypoxia. Moreover, lipid metabolism was reprogrammed, especially sphingolipid metabolism. Accordingly, the expression of the genes (i.e., SPTLC1, KDSR, SMPD3, SGPL1, and DGAT) involved was significantly altered. These results further prove the crucial role of HIF1α in mediating the lipid metabolism of insects under hypoxic stress conditions.