1. Complement C5a Induces Renal Injury in Diabetic Kidney Disease by Disrupting Mitochondrial Metabolic Agility
- Author
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Alison Skene, Trent M. Woodruff, Assam El-Osta, Mark E. Cooper, Kevin Huynh, Adrienne Laskowski, Darren C. Henstridge, Scott T. Baker, Vicki Thallas-Bonke, Matthew Snelson, Renata Libianto, Rick A. Wetsel, Melinda T. Coughlan, Peter J. Meikle, Josephine M. Forbes, Richard J MacIsaac, Sih Min Tan, Mark Ziemann, Scott Wilson, Tuong-Vi Nguyen, Michele V Clarke, Elif I Ekinci, David A. Power, and Vinod Kumar
- Subjects
Male ,0301 basic medicine ,Endocrinology, Diabetes and Metabolism ,Complement C5a ,Mice, Transgenic ,030209 endocrinology & metabolism ,Inflammation ,Pharmacology ,Mitochondrion ,Kidney ,Diabetes Mellitus, Experimental ,Rats, Sprague-Dawley ,Mice ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Downregulation and upregulation ,Diabetes mellitus ,Internal Medicine ,medicine ,Cardiolipin ,Animals ,Humans ,Diabetic Nephropathies ,Respiratory function ,Receptor, Anaphylatoxin C5a ,Cells, Cultured ,business.industry ,medicine.disease ,Fibrosis ,Mitochondria ,Rats ,Mice, Inbred C57BL ,030104 developmental biology ,medicine.anatomical_structure ,chemistry ,medicine.symptom ,Energy Metabolism ,business ,Signal Transduction ,Kidney disease - Abstract
The sequelae of diabetes include microvascular complications such as diabetic kidney disease (DKD), which involves glucose-mediated renal injury associated with a disruption in mitochondrial metabolic agility, inflammation, and fibrosis. We explored the role of the innate immune complement component C5a, a potent mediator of inflammation, in the pathogenesis of DKD in clinical and experimental diabetes. Marked systemic elevation in C5a activity was demonstrated in patients with diabetes; conventional renoprotective agents did not therapeutically target this elevation. C5a and its receptor (C5aR1) were upregulated early in the disease process and prior to manifest kidney injury in several diverse rodent models of diabetes. Genetic deletion of C5aR1 in mice conferred protection against diabetes-induced renal injury. Transcriptomic profiling of kidney revealed diabetes-induced downregulation of pathways involved in mitochondrial fatty acid metabolism. Interrogation of the lipidomics signature revealed abnormal cardiolipin remodeling in diabetic kidneys, a cardinal sign of disrupted mitochondrial architecture and bioenergetics. In vivo delivery of an orally active inhibitor of C5aR1 (PMX53) reversed the phenotypic changes and normalized the renal mitochondrial fatty acid profile, cardiolipin remodeling, and citric acid cycle intermediates. In vitro exposure of human renal proximal tubular epithelial cells to C5a led to altered mitochondrial respiratory function and reactive oxygen species generation. These experiments provide evidence for a pivotal role of the C5a/C5aR1 axis in propagating renal injury in the development of DKD by disrupting mitochondrial agility, thereby establishing a new immunometabolic signaling pathway in DKD.
- Published
- 2019