DNAJB3 GOVERNS DIET-INDUCED OBESITY AND INSULIN RESISTANCE USING DIFFERENTIAL EXPRESSION ANALYSIS

Abstract

This study investigates how deletion of the molecular chaperone gene DNAJB3 influences obesity- and insulin-related gene expression pathways in mice exposed to high-fat and low-fat diets. Using a comprehensive RNA-sequencing (RNA-Seq) bioinformatics pipeline, transcriptomic profiles were analyzed across four groups: WT-LFD, WT-HFD, KO-LFD, and KO-HFD. The analysis included quality control, read preprocessing, genome alignment, gene quantification, differential expression testing, functional enrichment, and network exploration. The results revealed a clear hierarchy of transcriptional effects, with high-fat diet exerting the strongest influence (2,769 DEGs), followed by DNAJB3 genotype (431 DEGs) and limited genotype-diet interaction (13 DEGs). High-fat feeding induced a broad metabolic–inflammatory shift characterized by suppression of mitochondrial oxidative phosphorylation, downregulation of fatty acid oxidation and TCA cycle enzymes, and strong upregulation of inflammatory and immune-related genes. In contrast, DNAJB3 deletion produced a more targeted effect, selectively impairing lipid metabolic pathways while partially preserving mitochondrial function. Notably, the knockout condition triggered unexpected activation of muscle contractile and sarcomeric genes in adipose tissue, particularly under high-fat diet, suggesting cytoskeletal remodeling or loss of adipocyte identity under metabolic stress. Interaction effects primarily highlighted specific metabolic nodes, including Ces1f, with minimal transcriptional synergy between genotype and diet. The findings position DNAJB3 as a key regulator of lipid oxidative capacity and metabolic flexibility in white adipose tissue. Its loss disrupts lipid metabolism and reveals an unforeseen link to structural and muscle-like gene activation, while high-fat diet remains the dominant driver of metabolic dysfunction and inflammation. These insights advance the understanding of adipose tissue remodeling in obesity and highlight DNAJB3 as a potential therapeutic target for metabolic disease.

Date of Award	2026
Original language	American English
Awarding Institution	HBKU College of Science and Engineering