A conserved lncRNA regulates trehalose-glucose homeostasis through direct RNA-RNA interactions

Abstract

Trehalose is a primary circulating sugar in insects and essential for energy homeostasis, yet its non-coding RNA-based regulatory circuitry remains enigmatic. Here, we characterize a conserved long non-coding RNA, lncRNA1, as a post-transcriptional regulator of trehalose-glucose homeostasis in Lepidoptera. lncRNA1 encodes a structurally stable, pseudoknot-containing transcript that is strongly induced upon trehalose pathway perturbation and exhibits a reciprocal developmental expression pattern relative to the trehalose metabolism enzymes. RNAi-mediated silencing of lncRNA1 in Helicoverpa armigera elevates TPS/TPP and Treh transcript abundance, increases enzyme activities, reduces haemolymph trehalose, raises glucose. This drives broad transcriptomic and metabolomic reprogramming of carbohydrate, lipid, and growth-signalling pathways, resulting in accelerated larval growth. Overexpression of lncRNA1 reverses these phenotypes. Mechanistically, lncRNA1 physically associates with TPS/TPP and Treh mRNAs through evolutionarily conserved sequence motifs, modulating their post-transcriptional dynamics. Targeted deletion of these motifs abolishes regulatory activity and disrupts metabolic homeostasis. This regulatory axis is functionally conserved in Spodoptera frugiperda, validated across loss-of-function, gain-of-function, and cell-based systems. Our findings reveal a conserved lncRNA-based layer of post-transcriptional control over insect energy metabolism. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/738560v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@eabc51org.highwire.dtl.DTLVardef@f1aaeforg.highwire.dtl.DTLVardef@d64aforg.highwire.dtl.DTLVardef@14d38e2_HPS_FORMAT_FIGEXP M_FIG C_FIG