Ubiquitin Proteasome System Role in Diabetes-Induced Cardiomyopathy

This study investigated modifications in the ubiquitin proteasome system (UPS) in a mouse model of type 2 diabetes mellitus (T2DM) and their relationship to heart complications. db/db mice heart tissues were compared with WT mice tissues using RNA sequencing, qRT-PCR, and protein analysis to identify cardiac UPS modifications associated with diabetes. The findings unveiled a distinctive gene profile in the hearts of db/db mice with decreased levels of nppb mRNA and increased levels of Myh7, indicating potential cardiac dysfunction. mRNA levels of USP18 (deubiquitinating enzyme), psmb8, and psmb9 (proteasome β-subunits) were downregulated in db/db mice while mRNA levels of RNF167 (E3 ligase) were increased. Corresponding LMP2 and LMP7 proteins were downregulated in db/db mice, and RNF167 was elevated in Adult diabetic mice. Reduced expression of LMP2 and LMP7, along with increased RNF167 expression, may contribute to future cardiac deterioration commonly observed in diabetes. This study enhances our understanding of UPS imbalances in the hearts of diabetic mice and raises questions about the interplay between the UPS and other cellular processes, such as autophagy. Further exploration in this area could provide valuable insights into the mechanisms underlying diabetic heart complications and potential therapeutic targets.