Discovery of Novel, Potent, and Subtype Selective 5-HT2B Receptor Antagonist -MARY1 Induces Mitochondrial Biogenesis and Restores Renal Function and Recovery Following Acute Kidney Injury

Abstract

Kidney disease affects more than 10% of the global population and remains a leading cause of morbidity and mortality. Acute kidney injury (AKI), often triggered by ischemia, toxins, or sepsis, can resolve with adaptive repair but frequently progresses to acute kidney disease (AKD) and chronic kidney disease (CKD) through maladaptive mechanisms including persistent inflammation, fibrosis, and tubular senescence. Central to this transition is mitochondrial dysfunction in proximal tubular cells, which impairs oxidative phosphorylation and contributes to the progression of CKD. Mitochondrial biogenesis (MB), regulated by PGC-1α, NRF1, and TFAM, is essential for maintaining renal energy homeostasis, and pharmacological activators of MB have emerged as promising therapeutic strategies to alleviate mitochondrial dysfunction-associated diseases. Serotonin (5-HT) signaling exerts receptor-specific therapeutic effects on renal pathology. Research from our laboratory and others have shown that modulation of 5-HT1F, 5-HT2A/2B/2C receptors enhances mitochondrial bioenergetics and function, thereby restoring renal function and repair following AKI. Here we discovered a novel, potent and subtype-selective 5-HT2BR antagonist, MARY1, that induces MB in both in vitro and in vivo. The MB-inducing effects of MARY1 are mediated through the 5-HT2B receptor and dual activation of the PI3K/AKT and RAS/MEK/ERK signaling pathways, resulting in nuclear translocation of PGC-1α, increased mitochondrial dynamics proteins, and upregulation of β-oxidation in the renal cortex of naïve mice. Daily administration of MARY1 for 6 days following AKI improves renal function, restores mitochondrial homeostasis and renal vascular integrity, upregulates β-oxidation, and restores genes associated with proximal tubule repair. Moreover, daily treatment with MARY1 (0.3 mg/kg) for 12 days following AKI increases autophagic activity in the renal cortex of mice. Daily administration of MARY1 for 30 days following AKI mitigated fibro-inflammatory responses, suppressing epithelial–mesenchymal and endothelial–mesenchymal transition (VE-cadherin, vimentin, FSP1), and reduced renal fibrosis (TGF-β, COL1A1, α-SMA). Furthermore, MARY1 attenuated inflammation by downregulating NF-κB signaling, reducing proinflammatory chemokine CXCL10, while augmenting anti-inflammatory cytokines IL-9, IL-10, and IL-13. Importantly, MARY1 alleviated cell cycle arrest by decreasing p53 and p21 expression, and increased “successful repair” genes (ACSM2A, HNF4α) while suppressing most “failed repair” markers (VCAM1, COL3A1, PDGFR-β). Together, these findings identify MARY1 as a first-in-class 5-HT2B receptor antagonist that restores mitochondrial function, promotes adaptive tubular repair, and prevents renal fibrosis, thereby alleviating AKD-to-CKD transition. This work highlights 5-HT2B receptor antagonism as a promising therapeutic strategy to improve renal function and recovery and long-term outcomes after ischemic injury.