Morin Alleviates Fructose-Driven Disturbance of Podocyte Mitochondrial Energy Metabolism by Inhibiting Adenosine 5'-Monophosphate Deaminase Activity to Improve Glomerular Injury.

Background/Objectives: High fructose consumption is a significant risk factor for glomerular podocyte injury. This study aimed to identify the underlying mechanism of fructose-induced podocyte injury and explore the protective effect of the natural polyphenol morin. Methods: In vivo, high-fructose-diet-fed rats were used to evaluate podocyte injury through ultrastructural structure analysis, urinary albumin-to-creatinine ratio (UACR), and synaptopodin expression. In vitro, adenosine 5'-monophosphate deaminase (AMPD) expression and activity, mitochondrial function, and glycolytic flux were measured in mouse podocyte clone-5 (MPC5) exposed to 5 mM fructose, with molecular docking and siRNA interference assays validating morin's regulatory role. Results: High fructose significantly increased AMPD activity in the purine nucleotide cycle (PNC), leading to mitochondrial dysfunction and a compensatory activation of glycolysis in podocytes. Morin effectively mitigated podocyte injury and suppressed the upregulation of AMPD activity, potentially through targeting AMPD2, as evidenced by molecular docking, which demonstrated a strong binding affinity between morin and AMPD2. Similarly, AMPD2 knockdown markedly alleviated mitochondrial impairment and glycolysis activation, confirming the pivotal role of AMPD2 in fructose-induced podocyte injury. In high-fructose-diet-fed rats, morin substantially improved ultrastructural damage, as shown by reduced podocyte foot process effacement, decreased UACR, restored glomerular synaptopodin expression, and suppressed AMPD activity in the renal cortex. Conclusions: Morin alleviated high-fructose-induced podocyte injury by inhibiting AMPD activity in the PNC, highlighting AMPD2 as a potential therapeutic target for podocyte injury caused by high fructose intake. This study provides novel mechanistic insights into how morin counteracts mitochondrial energy disturbance in podocyte injury.