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Updated: Apr 23, 2026
Phenotypic Characterization of Macrophages from Rat Kidney by Flow Cytometry
Published on: October 18, 2016
Specific macrophage subtypes influence the progression of rhabdomyolysis-induced kidney injury
Julie Belliere1, Audrey Casemayou2, Laure Ducasse2
1Institut National de la Santé et de la Recherche Médicale (INSERM), U1048, Institute of Cardiovascular and Metabolic Diseases, Toulouse, France; Université de Toulouse III Paul Sabatier, Toulouse, France; Department of Nephrology and Organ Transplantation, Centre Hospitalier Universitaire Rangueil, Toulouse, France;
Abstract:
Rhabdomyolysis can be life threatening if complicated by AKI. Macrophage infiltration has been observed in rat kidneys after glycerol-induced rhabdomyolysis, but the role of macrophages in rhabdomyolysis-induced AKI remains unknown. Here, in a patient diagnosed with rhabdomyolysis, we detected substantial macrophage infiltration in the kidney. In a mouse model of rhabdomyolysis-induced AKI, diverse renal macrophage phenotypes were observed depending on the stage of the disease. Two days after rhabdomyolysis, F4/80(low)CD11b(high)Ly6b(high)CD206(low) kidney macrophages were dominant, whereas by day 8, F4/80(high)CD11b(+)Ly6b(low)CD206(high) cells became the most abundant. Single-cell gene expression analyses of FACS-sorted macrophages revealed that these subpopulations were heterogeneous and that individual cells simultaneously expressed both M1 and M2 markers. Liposomal clodronate-mediated macrophage depletion significantly reduced the early infiltration of F4/80(low)CD11b(high)Ly6b(high)CD206(low) macrophages. Furthermore, transcriptionally regulated targets potentially involved in disease progression, including fibronectin, collagen III, and chemoattractants that were identified via single-cell analysis, were verified as macrophage-dependent in situ. In vitro, myoglobin treatment induced proximal tubular cells to secrete chemoattractants and macrophages to express proinflammatory markers. At day 30, liposomal clodronate-mediated macrophage depletion reduced fibrosis and improved both kidney repair and mouse survival. Seven months after rhabdomyolysis, histologic lesions were still present but were substantially reduced with prior depletion of macrophages. These results suggest an important role for macrophages in rhabdomyolysis-induced AKI progression and advocate the utility of long-term follow-up for patients with this disease.
Insights
Macrophages play a critical role in acute kidney injury (AKI) following rhabdomyolysis. Depleting these immune cells improves kidney repair and survival in a mouse model, highlighting their therapeutic potential.
Area of Science:
- Nephrology
- Immunology
- Pathology
Background:
- Rhabdomyolysis can lead to life-threatening acute kidney injury (AKI).
- While macrophage infiltration is noted in rhabdomyolysis, their specific role in AKI pathogenesis is unclear.
- This study investigates the dynamic role of kidney macrophages in rhabdomyolysis-induced AKI.
Purpose of the Study:
- To elucidate the function of macrophages in the progression of rhabdomyolysis-induced AKI.
- To characterize renal macrophage phenotypes during different stages of AKI.
- To assess the therapeutic potential of macrophage depletion in mitigating AKI and promoting kidney repair.
Main Methods:
- Analysis of macrophage infiltration in a patient with rhabdomyolysis and in a mouse model of rhabdomyolysis-induced AKI.
- Phenotypic and single-cell gene expression analysis of kidney macrophages at different disease stages.
- Macrophage depletion using liposomal clodronate in mice.
- In vitro studies using myoglobin treatment on kidney cells and macrophages.
- Assessment of kidney fibrosis, repair, and survival post-macrophage depletion.
Main Results:
- Diverse macrophage phenotypes (e.g., F4/80lowCD11bhighLy6bhighCD206low and F4/80highCD11b(+)Ly6b(low)CD206high) were observed at different time points post-rhabdomyolysis.
- Single-cell analysis revealed heterogeneity within macrophage subpopulations, with cells expressing both M1 and M2 markers.
- Macrophage depletion significantly reduced early macrophage infiltration, disease progression markers (fibronectin, collagen III), and chemoattractant production.
- In vitro, myoglobin induced proximal tubular cells to secrete chemoattractants and macrophages to express proinflammatory markers.
- Macrophage depletion improved kidney repair, reduced fibrosis, and enhanced survival at 30 days and long-term (7 months) post-rhabdomyolysis.
Conclusions:
- Macrophages are crucial players in the progression of rhabdomyolysis-induced AKI.
- Targeting macrophages may offer a therapeutic strategy for managing rhabdomyolysis-induced AKI.
- Long-term follow-up is recommended for patients recovering from rhabdomyolysis due to persistent histologic lesions.
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