Profilin1 is required for prevention of mitotic catastrophe in murine and human glomerular diseases
Xuefei Tian, … , Rongguo Fu, Shuta Ishibe
Xuefei Tian, … , Rongguo Fu, Shuta Ishibe
Published October 17, 2023
Citation Information: J Clin Invest. 2023;133(24):e171237. https://doi.org/10.1172/JCI171237.
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Research Article Cell biology Nephrology

Profilin1 is required for prevention of mitotic catastrophe in murine and human glomerular diseases

Abstract

The progression of proteinuric kidney diseases is associated with podocyte loss, but the mechanisms underlying this process remain unclear. Podocytes reenter the cell cycle to repair double-stranded DNA breaks. However, unsuccessful repair can result in podocytes crossing the G1/S checkpoint and undergoing abortive cytokinesis. In this study, we identified Pfn1 as indispensable in maintaining glomerular integrity — its tissue-specific loss in mouse podocytes resulted in severe proteinuria and kidney failure. Our results suggest that this phenotype is due to podocyte mitotic catastrophe (MC), characterized histologically and ultrastructurally by abundant multinucleated cells, irregular nuclei, and mitotic spindles. Podocyte cell cycle reentry was identified using FUCCI2aR mice, and we observed altered expression of cell-cycle associated proteins, such as p21, p53, cyclin B1, and cyclin D1. Podocyte-specific translating ribosome affinity purification and RNA-Seq revealed the downregulation of ribosomal RNA-processing 8 (Rrp8). Overexpression of Rrp8 in Pfn1-KO podocytes partially rescued the phenotype in vitro. Clinical and ultrastructural tomographic analysis of patients with diverse proteinuric kidney diseases further validated the presence of MC podocytes and reduction in podocyte PFN1 expression within kidney tissues. These results suggest that profilin1 is essential in regulating the podocyte cell cycle and its disruption leads to MC and subsequent podocyte loss.

Authors

Xuefei Tian, Christopher E. Pedigo, Ke Li, Xiaotao Ma, Patricia Bunda, John Pell, Angela Lek, Jianlei Gu, Yan Zhang, Paulina X. Medina Rangel, Wei Li, Eike Schwartze, Soichiro Nagata, Gabriel Lerner, Sudhir Perincheri, Anupama Priyadarshini, Hongyu Zhao, Monkol Lek, Madhav C. Menon, Rongguo Fu, Shuta Ishibe

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Figure 6

Differentially expressed genes analyzed by podocyte-specific RNA-Seq in Pfn1-KO TRAP mice.

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Differentially expressed genes analyzed by podocyte-specific RNA-Seq in ...
(A and B) Heatmap representing color-coding of the highest upregulated (A) and downregulated (B) differentially expressed genes (DEGs) in podocytes analyzed by Z ratio in Pfn1-KO translating ribosome affinity purification (Pfn1-KO TRAP) mice compared with control TRAP mice at 3 weeks of age. n = 2 samples in control and n = 3 samples in Pfn1 KO. Purified 3-mouse podocyte mixtures were used as 1 sample to ensure enough podocyte yields for RNA-Seq analysis. (C) The top significant enriched signaling pathways according to GO and KEGG pathways. The signaling pathways in the red tangle depict the top 4 signaling pathways. (D) Three shared DEGs involved in these top 4 signaling pathways were analyzed by Venny 2.1. RP, RNA processing; RCB, ribonucleoprotein complex biogenesis; CO, chromatin organization; MCC, mitotic cell cycle. (E) Real-time PCR of the primary control and Pfn1-KO podocytes for validation of these 3 candidates DEGs, including Kat2b, Dicer1, and Rrp8 from D. n = 6. *P < 0.05 vs. control. Statistics were analyzed via a 2-tailed t test.