Related Experiment Video
Updated: Aug 6, 2026
Comparative Proteomic Analysis of Whole Kidney, Medulla, and Cortical Tubules in Diabetic Pathogenesis of Kidney Injury in Mice
Published on: May 2, 2025
Effect of complement 3/5 knockout on renal proteomics landscape after ischemia and reperfusion injury in rats
Dinesh Bhattarai1,2, Amod Sharma1, Madison McGraw1
1Department of Pharmacology and Toxicology, University of Arkansas for Medical Science, Little Rock, Arkansas, USA.
Abstract:
Ischemia-reperfusion injury (IRI) is a major driver of acute kidney injury and development of chronic kidney disease. Although complement activation worsens IRI, the roles of upstream (C3) versus downstream (C5) components remain unclear. Renal IRI was surgically induced in C3 knockout (C3-/-) and C5 knockout (C5-/-) Lewis rats, and the renal function as well as histopathology were systematically assessed. Further, quantitative proteomics coupled with pathway enrichment analysis was performed to define complement-dependent mechanisms. C3 and C5 deficiency conferred strong protection against renal IRI with improved renal function, reduced tubular necrosis, and lower expression of injury markers (KIM-1, NGAL). Post-IRI, C3-/- enhanced mitochondrial, metabolic, and purine pathways while suppressing immune and extra-cellular matrix programs. C5-/- affected extracellular matrix remodeling and structural pathways with modest immune suppression. We demonstrate for the first time that upstream C3-/- impacts a diverse range of renal injury and repair mechanisms compared to C5-/- alone, although both interventions successfully reduced IRI-mediated injury. Together, these findings highlight strategies for future complement-based therapies targeting the upstream or downstream cascade.
Insights
Complement activation worsens kidney injury. Blocking C3 or C5 protected against ischemia-reperfusion injury (IRI), with C3 deficiency impacting broader repair pathways than C5 deficiency.
Area of Science:
- Nephrology
- Immunology
- Molecular Biology
Background:
- Ischemia-reperfusion injury (IRI) is a significant cause of acute kidney injury and chronic kidney disease.
- Complement activation exacerbates IRI, but the distinct roles of upstream (C3) and downstream (C5) components are not fully understood.
Purpose of the Study:
- To investigate the protective effects of C3 and C5 deficiency against renal IRI.
- To elucidate the molecular mechanisms underlying complement-dependent renal injury and repair.
Main Methods:
- Renal IRI was induced in C3 knockout (C3-/-) and C5 knockout (C5-/-) rats.
- Renal function and histopathology were assessed.
- Quantitative proteomics and pathway enrichment analysis were performed.
Main Results:
- Both C3 and C5 deficiency provided significant protection against renal IRI, improving renal function and reducing tubular necrosis.
- C3 deficiency enhanced mitochondrial, metabolic, and purine pathways while suppressing immune and extracellular matrix programs.
- C5 deficiency primarily affected extracellular matrix remodeling and structural pathways with mild immune suppression.
Conclusions:
- Both upstream C3 and downstream C5 complement components contribute to renal IRI.
- C3 deficiency influences a wider array of renal injury and repair pathways compared to C5 deficiency alone.
- Targeting upstream or downstream complement cascades offers potential therapeutic strategies for IRI.
