Helicoverpa armigera miR-2055 regulates lipid metabolism via fatty acid synthase expression

Abstract

Insect hormones and microRNAs regulate lipid metabolism, but the mechanisms are not fully elucidated. Here, we found that cotton bollworm larvae feeding on Arabidopsis thaliana (AT) leaves had a lower triacylglycerol (TAG) level and more delayed development than individuals feeding on artificial diet (AD). Association analysis of small RNA and mRNA revealed that the level of miR-2055, a microRNA related to lipid metabolism, was significantly higher in larvae feeding on AT. Dual-luciferase reporter assays demonstrated miR-2055 binding to 3′ UTR of fatty acid synthase (FAS) mRNA to suppress its expression. Elevating the level of miR-2055 in larvae by agomir injection decreased FAS mRNA and protein levels, which resulted in reduction of free fatty acid (FFA) and TAG in fat body. Interestingly, in vitro assays illustrated that juvenile hormone (JH) increased miR-2055 accumulation in a dosage-dependent manner, whereas knockdown of Methoprene tolerant (Met) or Kruppel homologue 1 (Kr-h1) decreased the miR-2055 level. This implied that JH induces the expression of miR-2055 via a Met-Kr-h1 signal. These findings demonstrate that JH and miRNA cooperate to modulate lipid synthesis, which provides new insights into the regulatory mechanisms of metabolism in insects.

The Key Role of Fatty Acid Synthase in Lipid Metabolism and Metamorphic Development in a Destructive Insect Pest, Spodoptera litura (Lepidoptera: Noctuidae)

“…It is well accepted that lipid accumulation affects insect growth and development [ 30 ]. In the present study, our results show that body weight in each developmental time point was not significantly different between the dsSlFAS1 -injection larvae and dsGFP -injection cohorts.…”

“…The lipid of fat bodies in third instar larvae was observed by staining with Nile red [ 30 ]. The fat bodies of S. litura larvae were dissected and washed with 1 × PBS (pH = 7.4) three times, each washing procedure lasting 5 min; subsequently, the fat bodies were fixed with 4% paraformaldehyde on a glass slide for 30 min at 4 °C.…”

Wds-Mediated H3K4me3 Modification Regulates Lipid Synthesis and Transport in Drosophila

“…Lipid homeostasis is determined by synthesis, transport, and mobilization and is crucial for insect growth and development [ 8 , 13 , 41 , 42 , 43 ]. Increasing evidence has revealed that numerous factors, including endocrine hormones, transcription factors, and microRNA, are involved in the regulation of lipid homeostasis [ 44 , 45 ]. H3K4me3 modification is epigenetically involved in transcriptional activation by relaxing the chromatin status at target loci and has been shown to be associated with various biological processes, such as stem cell proliferation and differentiation, development, memory formation, cancer, and autoimmune diseases [ 26 , 27 , 46 , 47 ].…”

Thermal Stress Induces Metabolic Responses in Juvenile Qingtian Paddy Field Carp Cyprinus carpio var qingtianensis

“…Our results show that heat stress regulates lipid metabolism and keeps metabolic homeostasis in check by altering gene expression and metabolite levels in juvenile PF carp exposed to varying thermal regimes. In the past, lipids have been thought of as one of the primary sources of energy that are found in the body [ 52 ]. However, in more recent times, it has been found that lipids also play an important role in the composition of cellular structure [ 53 ], the regulation of signaling factors [ 53 ], and the regulation of host immunity and metabolism [ 54 , 55 ].…”