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Abstract: FR-PO0749

Expression and Genetic Analyses of SLIT2 and ROBO2 in Kidney Macula Densa Cells

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: Mechanisms, including Podocyte Biology

Authors

  • Fan, Xueping, Boston University, Boston, Massachusetts, United States
  • Kumar, Sudhir, Boston University, Boston, Massachusetts, United States
  • Ledeboer-Cid, Ana, Boston University, Boston, Massachusetts, United States
  • Alford, Jacqueline, Boston University, Boston, Massachusetts, United States
  • Kierul, Olivia, Boston University, Boston, Massachusetts, United States
  • Izuhara, Audrey, University of Southern California, Los Angeles, California, United States
  • Gyarmati, Georgina, University of Southern California, Los Angeles, California, United States
  • Peti-Peterdi, Janos, University of Southern California, Los Angeles, California, United States
  • Lu, Weining, Boston University, Boston, Massachusetts, United States
Background

SLIT2 and its receptor ROBO2 are crucial for kidney development and podocyte function. Mutations or knockout of either SLIT2 or ROBO2 cause Congenital Anomalies of the Kidneys and Urinary Tracts (CAKUT) in humans and mice. Single-cell RNA sequencing data suggested that SLIT2 and ROBO2 are also expressed in the kidney macula densa (MD) cells. However, the expression patterns and functions of SLIT2 and ROBO2 in the MD cells remain unknown.

Methods

SLIT2 and ROBO2 mRNA expressions were analyzed by RNAscope in situ hybridization and were co-localized with MD cell-specific markers NOS1, PAPPA2, PTGS2, and NKCC2. The SLIT2/ROBO2 protein expressions in MD cells were confirmed by co-immunofluorescence staining. The functional activities of SLIT2 in MD cell lines MMDD1 and MDGeo were analyzed by the co-culture SVZa neuronal cell migration assay. We also generated a Slit2 MD-specific conditional knockout mouse with Nos1Cre (Slit2-flox/flox;Nos1Cre or Slit2 cKO) and investigated its phenotype.

Results

We found that SLIT2 and ROBO2 mRNA are highly expressed in adult mouse MD cells and are co-localized with MD cell-specific markers NOS1, NKCC2, PAPPA2, and PTGS2. The expression of SLIT2 and ROBO2 proteins in MD cells was confirmed by co-immunofluorescence staining with NOS1. Although MMDD1 and MDGeo cells did not exhibit positive SLIT2 chemo-repulsive activities in the co-culture SVZa neuronal cell migration assay, the Slit2 cKO mice displayed a unilateral CAKUT phenotype with reduced ROBO2 expression.

Conclusion

SLIT2 and ROBO2 are highly expressed in the mouse MD cells. Although MD cell lines do not secrete functional SLIT2, loss of SLIT2 in NOS1+ cells can lead to the CAKUT phenotype. Future studies are needed to provide a mechanistic understanding of SLIT2 and ROBO2 in MD cells in kidney development and physiology.

Funding

  • NIDDK Support

Digital Object Identifier (DOI)