PM20D1 and Vitamin D in CKD: A Potential Strategy Against Cachexia

Background: To investigate whether vitamin D, commonly deficient in chronic kidney disease (CKD), can regulate PM20D1 expression via VDR to convert excess free fatty acids and amino acids into N-acyl amino acids, potentially mitigating hyperlipidemia, hyperinsulinemia, uremia, and cachexia in advanced CKD. Methods: We conducted a systematic PubMed search (2018–2025, English) using “PM20D1”, “Vitamin D”, “Chronic Kidney Disease”, “N-acyl-amino-acids”, “cachexia” and “uremia.” After excluding duplicates and irrelevant studies, 25 remained. We also examined GTEx expression data and employed JASPAR (MA0693) with FIMO to identify VDR-binding sites. Results: PM20D1 functions as a dual enzyme, supplying an alternative thermogenic path and serving as a metabolic buffer via N-acyl amino acid synthesis/hydrolysis. In CKD, where free fatty acids and amino acids accumulate due to excessive catabolism, PM20D1 helps counter energy imbalance. Yet vitamin D deficiency raises uncoupling proteins (UCP1/3), intensifies lipolysis/proteolysis, and hastens cachexia. Vitamin D replenishment partly reverses adipose browning, improves muscle mass, and may boost PM20D1 buffering. GTEx data show an inverse relation between CYP24A1, crucial for calcitriol breakdown, and PM20D1, implying high CYP24A1 in kidney/liver limits vitamin D availability and hampers PM20D1 induction by VDR. Conversely, lower CYP24A1 in subcutaneous adipose correlates with elevated PM20D1. A predictive analysis (MA0693) identified two binding sites (p<0,0001) in the PM20D1 promoter, indicating direct transcriptional regulation. Inflammatory factors further heighten CYP24A1, degrading vitamin D and weakening PM20D1’s buffering, fueling catabolic stress. Conclusion: Overall, PM20D1 emerges as a crucial enzymatic factor whose efficacy depends on adequate vitamin D signaling. By converting surplus fatty acids and amino acids into N-acyl amino acids, PM20D1 may partly offset catabolic states driven by vitamin D deficiency, inflammation, and elevated uncoupling proteins. Discovery of two VDR-binding sites in the PM20D1 promoter underscores the importance of vitamin D in metabolic homeostasis. Future work should explore interventions optimizing both PM20D1 function and vitamin D levels to slow cachexia and improve CKD outcomes.