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Characterization of the Role of Shroom3 in Nephron Formation
Author(s) -
Kitala Patricia,
Cunanan Joanna,
Bridgewater Darren
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.208.2
Subject(s) - nephron , mesenchyme , microbiology and biotechnology , kidney development , biology , kidney , ureteric bud , embryonic stem cell , morphogenesis , cell type , mesenchymal stem cell , cell , medicine , endocrinology , biochemistry , gene
During kidney development the proper formation of the nephron, the functional unit of the kidney, is essential for normal kidney function. Nephrogenesis is the process in which nephron progenitors undergo cell shape changes and mesenchymal‐to‐epithelial transition to form mature nephrons. These cell shape changes are essential for the proper development of the nephron and for proper nephron function. Shroom3 is an actin‐binding protein that regulates epithelial cell shape. It regulates this morphogenesis by binding to F actin and interacting with Rho‐kinase. This leads to the phosphorylation of non‐muscle myosin II activating a signal pathway that causes contraction of the actomysoin network. This contraction causes the cell to form “pie” shaped cells, a process that is essential for tubule formation. Kidneys from shroom3 null mice have numerous abnormal nephrons with collapsing glomeruli at embryonic day E18.5, supporting a role for shroom3 in nephron formation. We hypothesize that Shroom3 is required for mesenchyme cells to cluster and form cell aggregates, pretubular aggregates, and renal vesicles. To support a role for Shroom3 in nephrogenesis we first localized Shroom3 expression. Shroom3 was highly expressed in the aggregating mesenchyme, renal vesicle, and parietal and visceral epithelial cells of the developing glomeruli. In contrast to wild‐type Shroom3 mice, E13.5 kidney histology of Shroom3 mutants demonstrated an increased distance of mesenchymal cells from the neighbouring ureteric bud tip cells (WT 3.85μm ± 0.30, MUT 14.80 μm ±1.22, n=9). These abnormalities were further observed by immunofluorescence (IF) using Six2 and Pax2, specific markers of the mesenchyme aggregates. In E13.5, the IF demonstrated an increased length in the cap mesenchyme (WT 179.6μm ± 24.96, MUT 306.4μm ± 33.30, n=9), and a lack of cap mesenchyme cell aggregation in Shroom3 mutants (WT 8804μm 2 ±1250, MUT 12353 μm 2 ±1504, n=9). In addition, E18.5 mutants displayed significantly less Six2+ cells in comparison to wild‐types (WT 149 ± 13.3, MUT 79.5 ± 7.47). The analysis for renal vesicles in Shroom3 mutants at E13.5 and E18.5 demonstrated abnormally forming renal vesicles that were few in number when compared to wild‐type (WT 3 ±0.58, MUT 1 ± 0, n=9). Taken together, our findings establish, for the first time, that Shroom3 is essential for the early stages of nephron formation, and suggest these early changes lead to improper migration and clustering of cap mesenchyme cells resulting in abnormal nephrons observed in null mice. Support or Funding Information CIHR, NSERC, KFOC This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .