Critical Role of microRNA-33a/b in Cardiovascular and Metabolic Disease: Molecular Mechanisms and Therapeutic Perspectives.

MicroRNAs (miRNAs) serve as fundamental post-transcriptional regulators of gene expression, among which the miR-33 family, consisting of miR-33a and miR-33b, has emerged as a critical modulator in the pathogenesis of cardiovascular and metabolic diseases. These miRNAs are embedded within the intronic regions of SREBF genes and play pivotal roles in cholesterol homeostasis, fatty acid metabolism, and inflammatory regulation. Notably, miR-33a is highly conserved across various species, whereas miR-33b is found primarily in primates and some other mammals, complicating the development of relevant animal models. These miRNAs inhibit their target genes involved in cholesterol metabolism, fatty acid oxidation, and insulin signaling, consequently influencing the development and progression of cardiovascular and metabolic diseases. Inhibition or genetic ablation of miR-33 has shown therapeutic potential, improving dyslipidemia, atherosclerosis, and metabolic dysfunction-associated steatotic liver disease, through altered cholesterol metabolism, attenuation of inflammation, and increased fatty acid utilization. In addition, miR-33 suppression has been shown to promote skeletal muscle regeneration. However, systemic inhibition of miR-33 requires caution due to the role of miR-33 in hunger signaling and sympathetic nerve activity in the central nervous system, which may lead to obesity. Therefore, the development of tissue-specific strategies is essential for the safe and effective therapeutic targeting of miR-33.