Macula Densa Cell Gene Profiling

Macula densa (MD) cells are chief but still mysterious cells localized at a strategically important anatomical location at the glomerular entrance, and play key regulatory roles in renal and glomerular hemodynamics, body fluid and electrolyte homeostasis, and blood pressure maintenance. The present study aimed to establish the true nature of MD cells by performing unbiased MD gene profiling using two separate and independent approaches. A new mouse model (MD‐GFP mice) was generated with inducible and conditional MD‐specific expression of the fluorescence reporter EGFP by crossing nNOS‐CreERT2 and mTmG‐floxed mice. MD cells were freshly isolated from digested kidneys of MD‐GFP mice using FACS sorting, followed by MD RNA isolation and sequencing. Alternatively, MD RNA isolation and sequencing was performed in another new mouse model by crossing floxed L10a‐EGFP and nNOS‐CreERT2 mice and using the Translating Ribosome Affinity Purification (TRAP) strategy. Compared to whole kidney and adjacent non‐MD tubular epithelial cells, MD‐specific enriched genes included members of secreted angiogenic (Ccn1, Pappa‐2, Gdf15), extracellular matrix remodeling (Mmp14, Ca12), growth factor (Fgf2), developmental and differentiation transcription factor (Bmp3/7, Wnt10a, Hoxa1, Fos), cell cycle and DNA damage regulating (Gmnn, Wee1, Gadd45b) gene families. Our results paint a new picture of MD cells and suggest their new non‐traditional roles in renal interstitial, vascular, and glomerular tissue remodeling. Support or Funding Information NIH R01 64324, AHA, ADA