microRNA-34a-Sirtuin 1 signaling axis (miR-34a/SIRT1 axis)

The miR-34a-SIRT1 axis is a pivotal regulatory pathway involving the microRNA miR-34a and its direct target, the NAD+-dependent deacetylase Sirtuin 1 (SIRT1). This axis functions as a critical node in the p53-mediated stress response, where miR-34a suppresses SIRT1 expression by binding to its 3' UTR, thereby promoting p53 acetylation and enhancing apoptosis and cell cycle arrest. Dysregulation of this axis is implicated in a wide array of pathologies, including various cancers where miR-34a acts as a tumor suppressor, and metabolic or neurodegenerative diseases where its overexpression contributes to cellular senescence and tissue damage. Therapeutic strategies targeting this axis include miR-34a mimics for oncology and miR-34a inhibitors or SIRT1 activators for regenerative and neuroprotective applications. While preclinical results have been robust, clinical development has faced significant hurdles, most notably the termination of phase I trials for the miR-34a mimic MRX34 due to severe immune-related toxicities.

Other names

miR-34a/SIRT1 pathwaymiR-34a/SIRT1/p53 signaling pathwayp53-miR-34a-SIRT1 feedback loopmicroRNA-34a-SIRT1 regulatory axis

Drugs targeting this axis either mimic miR-34a to downregulate SIRT1 and promote apoptosis in cancer cells, or inhibit miR-34a to restore SIRT1 levels and provide cytoprotective effects in degenerative and ischemic conditions. SIRT1 activators like resveratrol can also counteract miR-34a-mediated suppression by enhancing the activity of the remaining SIRT1 enzyme.