MARY1 restores mitochondrial homeostasis and accelerates renal recovery following acute kidney injury

Abstract

Acute kidney injury (AKI) is a major clinical concern with limited therapeutic strategies, often leading to chronic kidney disease (CKD) and long-term morbidity. Mitochondrial dysfunction is a major causative factor for AKI onset and progression to CKD. Interventions that restore mitochondrial integrity and cellular energy represent promising therapeutic strategies. This study investigated the potential therapeutic role of MARY1, a novel, potent, and subtype-selective serotonin-2B receptor (5-HT_2BR) antagonist, following ischemia/reperfusion (I/R)-induced AKI in mice and rats. We previously demonstrated that MARY1 induces renal mitochondrial biogenesis (MB), the generation of new functional mitochondria, in vivo. MARY1 (0.3 mg/kg, i.p., daily) administration 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 for 12 days following AKI restores mitochondrial homeostasis and increases autophagic activity in the renal cortex of mice. These findings establish MARY1-mediated 5-HT_2BR antagonism as a mitochondria-targeted therapeutic strategy that addresses multiple hallmarks of AKI, and as a potential intervention for mitochondrial dysfunction-associated renal diseases.NEW & NOTEWORTHY This study identifies MARY1, a subtype selective 5-HT_2B receptor antagonist, as a novel mitochondria-targeted therapeutic for AKI. MARY1 restores mitochondrial homeostasis, enhances renal vascular integrity, and promotes autophagy and β-oxidation following bilateral I/R injury-induced AKI, leading to improved renal recovery in vivo. These findings highlight a novel therapeutic strategy to mitigate AKI progression and mitochondrial dysfunction.

Keywords: 5-hydroxytryptamine 2B receptor antagonism; acute kidney injury; mitochondrial dysfunction; renal function.

Figure 1.. MARY1 Restored Renal Function and Mitochondrial Homeostasis in the Renal Cortex of Mice 6d Following I/R-AKI.

(A) Serum creatinine 1 and 6 days after renal I/R injury in C57BL/6NCrl mice. (B) mtDNA and (C) total ATP content in the renal cortices of mice following AKI. (D) Representative transmission electron micrographs, (E) mitochondrial damage score, and (F) mitochondrial number in the renal cortices of mice following AKI. Green arrow indicates healthy mitochondria, and red arrow indicates damaged mitochondria. Densitometry analysis of (G) PGC-1α, (H) MFN1, and (I) MFN2, and (J) representative immunoblots in the renal cortices of mice following AKI. Data are represented as mean±SEM; n = 5–6; p< 0.05 considered as statistical significance. Letter ‘L’ represents protein ladder.

Figure 2.. MARY1 Restored Renal Vascular Integrity in the Renal Cortex of Mice 6d Following AKI.

(A) Renal vascular leakage as assessed using Evan’s blue dye (EBD) extravasation following AKI in mice. (B) Representative immunoblots and densitometry analysis of (C) occludin and (D) claudin-10 in the renal cortices of mice following AKI. Data are represented as mean±SEM; n = 4–6; p< 0.05 considered as statistical significance.

Figure 3.. MARY1 Restored β-oxidation and Successful Repair Genes in the Renal Cortex of Mice 6d Following AKI.

Densitometry analysis of (A) ACSM2A and (B) ACADM, and (C) representative immunoblots in the renal cortices of mice following AKI. qRT-PCR analysis of mRNA expression of (D) ACSM2A, (E) HNF4A, (F) LRP2, and (G) SLC5A12 in the renal cortices of mice following AKI. Data are represented as mean±SEM; n = 4–6; p< 0.05 considered as statistical significance. Letter ‘L’ represents protein ladder.

Figure 4.. MARY1 Restored Mitochondrial Homeostasis and Autophagy in the Renal Cortex of Mice 12d Following AKI.

(A) Serum creatinine 1, 6, and 12 days after renal I/R injury in C57BL/6NCrl mice. (B) mtDNA content in the renal cortices of mice following AKI. Densitometry analysis of (C) PGC-1α and (D) MFN2, and (E) representative immunoblots in the renal cortices of mice following AKI. Densitometry analysis of (F) ATG7, (G) ATG5, and (H) p62, and (I) representative immunoblots in the renal cortices of mice following AKI. Data are represented as mean±SEM; n = 5–6; p< 0.05 considered as statistical significance.

Figure 5.. MARY1 Restored Renal Function and Mitochondrial Proteins in the Renal Cortex of Rats 6d Following AKI.

(A) Serum creatinine 1 and 6 days after renal I/R injury in Crl:CD rats. Densitometry analysis of (B) PGC-1α and (C) ACSM2A, and (D) representative immunoblots in the renal cortices of rats following AKI. Data are represented as mean±SEM; n = 5–6; p< 0.05 considered as statistical significance.