Knockdown of Nicotinamide N-methyltransferase Ameliorates Renal Fibrosis Caused by Ischemia-reperfusion Injury and Remodels Sphingosine Metabolism

Overview

Journal Clin Exp Nephrol

Publisher Springer

Specialty Nephrology

Date 2024 Aug 21

PMID 39168882

Authors

Wanfeng Xu

Ling Hou

Affiliations

Soon will be listed here.

Abstract

Background: CKD currently affects 8.2% to 9.1% of the global population and the CKD mortality rate has increased during recent decades, making it necessary to identify new therapeutic targets. This study investigated the role of nicotinamide N-methyltransferase (NNMT) in renal fibrosis following ischemia-reperfusion injury (IRI), a key factor in chronic kidney disease (CKD) progression.

Methods: We established a mouse model with a knockdown of NNMT to investigate the impact of this enzyme on renal fibrosis after unilateral IRI. We then utilized histology, immunohistochemistry, and metabolomic analyses to investigate fibrosis markers and sphingolipid metabolism in NNMT-deficient mice. We also utilized an Nnmt lentivirus interference vector or an Nnmt overexpression plasmid to transfect mouse kidney proximal tubule cells, stimulated these cells with TGF-β1, and then measured the pro-fibrotic response and the expression of the methylated and unmethylated forms of Sphk1.

Results: The results demonstrated that reducing NNMT expression mitigated fibrosis, inflammation, and lipid deposition, potentially through the modulation of sphingolipid metabolism. Histology, immunohistochemistry, and metabolomic analyses provided evidence of decreased fibrosis and enhanced sphingolipid metabolism in NNMT-deficient mice. NNMT mediated the TGF-β1-induced pro-fibrotic response, knockdown of Nnmt decreased the level of unmethylated Sphk1 and increased the level of methylated Sphk1 in renal tubular epithelial cells.

Conclusions: Our findings suggest that NNMT functions in sphingolipid metabolism and has potential as a therapeutic target for CKD. Further research is needed to elucidate the mechanisms linking NNMT to sphingolipid metabolism and renal fibrosis.

References

Wang L, Xu X, Zhang M, Hu C, Zhang X, Li C . Prevalence of Chronic Kidney Disease in China: Results From the Sixth China Chronic Disease and Risk Factor Surveillance. JAMA Intern Med. 2023; 183(4):298-310. PMC: 9941971. DOI: 10.1001/jamainternmed.2022.6817. View

Liu J, Kumar S, Dolzhenko E, Alvarado G, Guo J, Lu C . Molecular characterization of the transition from acute to chronic kidney injury following ischemia/reperfusion. JCI Insight. 2017; 2(18). PMC: 5612583. DOI: 10.1172/jci.insight.94716. View

Gerhardt L, Liu J, Koppitch K, Cippa P, McMahon A . Single-nuclear transcriptomics reveals diversity of proximal tubule cell states in a dynamic response to acute kidney injury. Proc Natl Acad Sci U S A. 2021; 118(27). PMC: 8271768. DOI: 10.1073/pnas.2026684118. View

Gong S, Zhang A, Yao M, Xin W, Guan X, Qin S . REST contributes to AKI-to-CKD transition through inducing ferroptosis in renal tubular epithelial cells. JCI Insight. 2023; 8(11). PMC: 10393228. DOI: 10.1172/jci.insight.166001. View

Ferenbach D, Bonventre J . Mechanisms of maladaptive repair after AKI leading to accelerated kidney ageing and CKD. Nat Rev Nephrol. 2015; 11(5):264-76. PMC: 4412815. DOI: 10.1038/nrneph.2015.3. View

Takahashi R, Kanda T, Komatsu M, Itoh T, Minakuchi H, Urai H . The significance of NAD + metabolites and nicotinamide N-methyltransferase in chronic kidney disease. Sci Rep. 2022; 12(1):6398. PMC: 9013399. DOI: 10.1038/s41598-022-10476-6. View

Zhang W, Rong G, Gu J, Fan C, Guo T, Jiang T . Nicotinamide N-methyltransferase ameliorates renal fibrosis by its metabolite 1-methylnicotinamide inhibiting the TGF-β1/Smad3 pathway. FASEB J. 2022; 36(3):e22084. DOI: 10.1096/fj.202100913RRR. View

Tanaka Y, Kume S, Araki H, Nakazawa J, Chin-Kanasaki M, Araki S . 1-Methylnicotinamide ameliorates lipotoxicity-induced oxidative stress and cell death in kidney proximal tubular cells. Free Radic Biol Med. 2015; 89:831-41. DOI: 10.1016/j.freeradbiomed.2015.10.414. View

Gao Y, Martin N, van Haren M . Nicotinamide N-methyl transferase (NNMT): An emerging therapeutic target. Drug Discov Today. 2021; 26(11):2699-2706. DOI: 10.1016/j.drudis.2021.05.011. View

10.

Roberti A, Fernandez A, Fraga M . Nicotinamide N-methyltransferase: At the crossroads between cellular metabolism and epigenetic regulation. Mol Metab. 2021; 45:101165. PMC: 7868988. DOI: 10.1016/j.molmet.2021.101165. View

11.

Kraus D, Yang Q, Kong D, Banks A, Zhang L, Rodgers J . Nicotinamide N-methyltransferase knockdown protects against diet-induced obesity. Nature. 2014; 508(7495):258-62. PMC: 4107212. DOI: 10.1038/nature13198. View

12.

Hall Y, Himmelfarb J . The CKD Classification System in the Precision Medicine Era. Clin J Am Soc Nephrol. 2016; 12(2):346-348. PMC: 5293342. DOI: 10.2215/CJN.09310916. View

13.

Fu Y, Tang C, Cai J, Chen G, Zhang D, Dong Z . Rodent models of AKI-CKD transition. Am J Physiol Renal Physiol. 2018; 315(4):F1098-F1106. PMC: 6230729. DOI: 10.1152/ajprenal.00199.2018. View

14.

Hou L, Du Y . Neuropilin 1 promotes unilateral ureteral obstruction-induced renal fibrosis via RACK1 in renal tubular epithelial cells. Am J Physiol Renal Physiol. 2023; 325(6):F870-F884. DOI: 10.1152/ajprenal.00069.2023. View

15.

Xu W, Hou L, Li P, Li L . Effect of nicotinamide N-methyltransferase on lipid accumulation in 3T3-L1 adipocytes. Bioengineered. 2022; 13(5):12421-12434. PMC: 9276046. DOI: 10.1080/21655979.2022.2074768. View

16.

Ulanovskaya O, Zuhl A, Cravatt B . NNMT promotes epigenetic remodeling in cancer by creating a metabolic methylation sink. Nat Chem Biol. 2013; 9(5):300-6. PMC: 3631284. DOI: 10.1038/nchembio.1204. View

17.

Li L, Dahiya R . MethPrimer: designing primers for methylation PCRs. Bioinformatics. 2002; 18(11):1427-31. DOI: 10.1093/bioinformatics/18.11.1427. View

18.

Scantlebery A, Tammaro A, Mills J, Rampanelli E, Kors L, Teske G . The dysregulation of metabolic pathways and induction of the pentose phosphate pathway in renal ischaemia-reperfusion injury. J Pathol. 2020; 253(4):404-414. PMC: 7986929. DOI: 10.1002/path.5605. View

19.

Wei Q, Xiao X, Fogle P, Dong Z . Changes in metabolic profiles during acute kidney injury and recovery following ischemia/reperfusion. PLoS One. 2014; 9(9):e106647. PMC: 4156324. DOI: 10.1371/journal.pone.0106647. View

20.

Shen S, Wang J, Wu J, Zhou J, Meng S, Ma J . GC/MS-based metabolomic analysis of alleviated renal ischemia-reperfusion injury induced by remote ischemic preconditioning. Eur Rev Med Pharmacol Sci. 2017; 21(4):765-774. View