Limiting progressive fibrosis in chronic kidney disease (CKD) is an ongoing therapeutic challenge that requires effective and safe inhibition of a broad inflammatory cell milieu that leads to irreversible organ damage. Asengeprast, an anti-fibrotic and anti-inflammatory small molecule, has shown promising efficacy in animal models of kidney disease, however its target and mechanism of action was unknown. Using in vitro assays, we showed that asengeprast modulates inflammatory and fibrotic responses through selective inhibition of G protein-coupled receptor 68 (GPR68), a proton sensor, expressed in tissue-resident and immune-infiltrating cells of the kidney. Transcriptomic analysis of kidney tissue from animal models of diabetic kidney disease (DKD) and CKD demonstrated that fibrotic and inflammatory pathways dysregulated in disease were reversed by asengeprast treatment. Differential expression analysis of upstream regulators showed that the major, distinct signaling networks reversed were centered on a key driver of fibroblast activation, transforming growth factor β1, and associated signaling molecules. An asengeprast response gene signature derived from the CKD animal model when mapped onto gene expression profiles obtained from human kidney biopsies confirmed that the molecular pathways modulated by asengeprast were also dysregulated in human DKD and CKD. Further, this asengeprast response signature correlated with clinical markers of disease progression and tissue pathology. Overall, these findings provide evidence for targeted inhibition of GPR68 by asengeprast as a promising therapeutic strategy for treatment of CKD and potentially other fibrotic and inflammatory conditions.

Translational Statement Existing therapeutic strategies for chronic kidney disease (CKD) do not directly target both inflammatory and fibrotic processes needed to slow or halt the progression of disease.

Asengeprast is a Phase II candidate drug for CKD that blocks G protein-coupled receptor 68 in animal models to reverse inflammatory and fibrotic pathways, thereby improving kidney function. These same pathways were shown to be dysregulated in human CKD, providing strong evidence that the therapeutic effects observed in pre-clinical models will translate to the clinic. Using a novel mechanism of action, asengeprast has the potential to significantly improve the lives of patients with CKD.

All data presented were sponsored by Certa Therapeutics. Darren J Kelly, Fay L Khong, Michelle Papadimitriou and Simona Carbone are/were employees of Certa Therapeutics. Amanda J Edgley, Roy Kong and Robyn Langham are/were advisors/consultants of Certa Therapeutics. Darren J Kelly is a founder and shareholder in Certa Therapeutics. Sean Eddy receives funding support through the University of Michigan from AstraZeneca PLC, Eli Lilly and Company, NovoNordisk, and Travere Therapeutics and has received grant support from Gilead Sciences Inc, Moderna Inc, and IONIS Pharmaceuticals Inc outside of the scope of work for this manuscript, and from Certa Therapeutic in support of this work. M Kretzler reports grants and contracts through the University of Michigan with Chan Zuckerberg Initiative, AstraZeneca, NovoNordisk, Eli Lilly, Gilead, Goldfinch Bio, Janssen, Boehringer-Ingelheim, Moderna, European Union Innovative Medicine Initiative, Certa Therapeutics, Chinook, amfAR, Angion, RenalytixAI, Travere, Regeneron, IONIS. Consulting fees through the University of Michigan from Astellas, Poxel, Janssen and UCB. In addition, M.K. has a patent PCT/EP2014/073413 licensed. The remaining authors declare no competing interests.

The Nephrotic Syndrome Study Network Consortium (NEPTUNE), U54-DK-083912, is a part of the National Institutes of Health (NIH) Rare Disease Clinical Research Network (RDCRN), supported through collaboration between the Office of Rare Diseases Research, National Center for Advancing Translational Sciences, and the National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK). Additional funding and/or programmatic support for this project has also been provided by NephCure Kidney International, the Halpin Foundation, and the Applied Systems Biology Core at the University of Michigan George M. OBrien Kidney Translational Core Center (2P30-DK-08194). LHM is supported through funding from NIH/NIDDK, K08 DK115891-01.

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