DREAM and the dysfunction of perivascular adipose tissue in obesity

• Grant number: 24/06637-5
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2025
• End date: September 30, 2027
• Field of knowledge: Biological Sciences - Pharmacology - Cardiorenal Pharmacology
• Principal Investigator: Rita de Cassia Aleixo Tostes Passaglia
• Grantee: Victor Oliveira Assis
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 13/08216-2 - CRID - Center for Research in Inflammatory Diseases, AP.CEPID

Abstract

Obesity is a global epidemic associated with a range of cardiovascular complications, including dysfunction of perivascular adipose tissue (PVAT), which plays a crucial role in modulating vasoconstrictor responses. In obesity, PVAT undergoes pathological changes characterized by increased production of vasoconstrictor and pro-inflammatory molecules, along with a reduction in its anti-contractile effect. Inflammation, involving immune cell infiltration, plays a central role in PVAT dysfunction. DREAM (Downstream Regulatory Element Antagonist Modulator) is a known transcriptional repressor that regulates inflammation in pathological contexts. DREAM inhibits the transcription of the anti-inflammatory gene A20, which can suppress the activation of the NF-¿B complex. In pathophysiological conditions, enhanced DREAM repressor activity amplifies pro-inflammatory mechanisms. However, its role in PVAT dysfunction during obesity remains unknown. The aim of this study is to investigate whether DREAM contributes to PVAT inflammation and, consequently, to its dysfunction during obesity. Our hypothesis is that in obesity, increased DREAM activity promotes the activation of pro-inflammatory pathways and the development of a pro-inflammatory PVAT profile, leading to vascular dysfunction. C57BL/6J (WT) mice, total DREAM knockout mice (DREAM-KO), and mice with DREAM deletion specifically in adipocytes (AdiponectinCreDREAMfl/fl) at 8 weeks of age will be treated with a high-fat diet for 16 weeks. Vascular function will be assessed through reactivity studies with thoracic aortas with and without PVAT. DREAM activity will be inferred by Western blot, qRT-PCR, and chromatin immunoprecipitation assays. As effector mechanisms, increased expression of adhesion molecules, NF-¿B activation, immune cell infiltration, and cytokine production will be evaluated by Western blot, flow cytometry, and ELISA, respectively. The supernatant from adipocyte cultures (control and DREAM knockdown via siRNA) incubated with palmitate will be used to stimulate endothelial and smooth muscle cell cultures to determine whether adipocyte-specific DREAM contributes to the dysfunction of other vascular structures; pro- and anti-inflammatory cytokine production will be measured by ELISA. To assess whether inflammatory infiltration occurs in other fat depots, tissue morphology and immune cell presence in visceral, subcutaneous, and subscapular fat samples from obese WT, DREAM-KO, and AdiponectinCreDREAMfl/fl mice will be evaluated using histological techniques. The objective is to elucidate whether (and how) DREAM directly regulates inflammatory targets in PVAT during obesity. Identifying the mechanisms by which DREAM influences the inflammatory process in PVAT may provide essential foundations for the development of therapeutic strategies aimed at modulating inflammation and improving vascular health, not only in obesity-related conditions but also in other scenarios characterized by inflammatory processes.