M-1 Cells

The M-1 cell line is a well-characterized epithelial model derived from the kidney of a transgenic adult mouse. Specifically, M-1 cells originate from the cortical collecting duct epithelium and retain many differentiated features of this nephron segment. These cells express markers typical of cortical collecting duct cells, including epithelial sodium channels (ENaC), aquaporins, and tight junction proteins, making them a widely used in vitro model for renal physiology, ion transport, and epithelial polarity studies. Functionally, M-1 cells exhibit high transepithelial resistance and vectorial ion transport properties, which are critical for studying aldosterone-regulated sodium reabsorption and vasopressin-mediated water transport. According to the foundational characterization by Stoos et al., M-1 cells form polarized monolayers on permeable supports and show appropriate responsiveness to hormonal stimuli, such as dexamethasone and aldosterone, that regulate transport protein expression and activity. These features make M-1 cells particularly valuable in dissecting mechanisms of electrolyte handling and cellular signaling in kidney epithelial cells. Moreover, M-1 cells have been validated in more recent studies, including genetic authentication using STR profiling for mouse cell lines. This underscores their continued relevance and reliability in contemporary renal physiology research. Their ability to recapitulate in vivo-like behaviors under controlled conditions has established them as a standard in studies on epithelial function, nephrotoxicity, and renal disease modeling.