Canonical Wnt transcriptional complexes are essential for induction of nephrogenesis but not maintenance or proliferation of nephron progenitors
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1.
University of Southern California
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2.
Icahn School of Medicine at Mount Sinai
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3.
Semmelweis University
Abstract
AbstractWnt regulated transcriptional programs are associated with both the maintenance of mammalian nephron progenitor cells (NPC) and their induction, initiating the process of nephrogenesis. How opposing transcriptional roles are regulated remain unclear. Using anin vitromodel replicatingin vivoevents, we examined the requirement for canonical Wnt transcriptional complexes in NPC regulation. In canonical transcription, Lef/Tcf DNA binding proteins associate the transcriptional co-activator β-catenin. Wnt signaling is readily substituted by CHIR99021, a small molecule antagonist of glycogen synthase kinase-3β (GSK3β). GSK3β inhibition blocks Gskβ-dependent turnover of β-catenin, enabling formation of Lef/Tcf/β-catenin transcriptional complexes, and enhancer-mediated transcriptional activation. Removal of β-catenin activity from NPCs under cell expansion conditions (low CHIR) demonstrated a non-transcriptional role for β-catenin in the CHIR-dependent proliferation of NPCs. In contrast, CHIR-mediated induction of nephrogenesis, on switching from low to high CHIR, was dependent on Lef/Tcf and β-catenin transcriptional activity. These studies point to a non-transcriptional mechanism for β-catenin in regulation of NPCs, and potentially other stem progenitor cell types. Further, analysis of the β-catenin-directed transcriptional response provides new insight into induction of nephrogenesis.Summary StatementThe study provides a mechanistic understanding of Wnt/ β-catenin activity in self-renewal and differentiation of mammalian nephron progenitors.
Acknowledgement
We thank former and current members of the McMahon laboratory for helpful comments, technical assistance and useful discussion especially Jill McMahon, JinJin Guo, Muskaan Singh, Dr. Tracy Tran, Dr. Kevin Peterson and Dr. Qiuyu Guo. We thank Dr. Christopher Garcia and Dr. Yi Miao for sharing the Wnt mimetic bi-specific antibody. We are grateful for the assistance of Dr. Seth Ruffins in the biological imaging core facility and Bernadette Masinsin in flow core facility and thank our colleagues Dr. Yulia Schwartz and Dr. Unmesh Jadhav for illuminating discussions.
Funding
Work in APM’s laboratory was supported by grants NIH grants R01 DK054364 to APM and F31 DK122777 to HB.
Conflict of Interest
APM is a consultant or scientific advisor to Novartis, eGENESIS, Trestle Biotherapeutics and IVIVA Medical. Other authors declare no conflict of interest.
Contributions
HB and APM conceived the study. HB and BD, performed experiments and collected data. HB, BD, NOL and SK performed various analyses on the data. HB and APM wrote the manuscript incorporating comments from all authors.
Data Availability
The bulk mRNA-seq for this study can be found at GEO accession number (GSE231753). The mouse embryonic kidney single cell RNA is deposited at GEO accession number (GSE232482) the human fetal kidney single data is deposited at at GEO accession number (GSE139280). The GEO accession number for the bulk mRNA seq data in the corresponding manuscript is (GSE232606).
Additional Information
In order to advance our educational, scientific and clinical mission, USC Stem Cell is deeply committed to creating a culture that supports diversity, equity and inclusion (DEI). HB identifies as an underrepresented minority female in STEM and benefitted from funds from the Ruth L. Kirschstein National Research Service Award (NRSA) Individual Predoctoral Fellowship to Promote Diversity in Health-Related Research (Parent F31-Diversity) and F31 DK122777.
Copyright and License
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission.
Supplemental Material
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Table S1[supplements/554044_file18.xlsx]
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Table S2[supplements/554044_file19.xlsx]
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Additional details
- Caltech groups
- Division of Biology and Biological Engineering
- Publication Status
- Submitted