Visualizing calcium dynamics in the kidney
In this issue of the Journal of Clinical Investigation, Janos Peti-Peterdi and colleagues at the University of Southern California used multiphoton microscopy (MPM) to directly visualize podocyte calcium dynamics within the intact kidneys of live mice.
A robust calcium wave was generated in response to glomerular injury and this signal spread throughout cells.
Mice lacking the P2Y2 purinergic receptor or treated with inhibitors of calcium signaling prevented propagation of a calcium wave.
Furthermore, increased calcium signaling correlated with loss of glomerular filter integrity.
Together this results suggest that calcium signaling mediates pathogenic responses to injury in the kidney.
Characterization of an asplenic patient with disorder of sexual development
Mutations with in the gene encoding the transcription factor steroidogenic factor 1 (SF-1) are associated with disorders of sexual development (DSD), including sex reversal, spermatogenic failure, ovarian insufficiency, and adrenocortical deficiency.
In this issue of the Journal of Clinical Investigation, David Zangen and colleagues at Hadassah Hebrew University Medical Centre identified a recessive mutation within SF1 that resulted in both severe 46,XY-DSD and asplenia in a pediatric patient.
Interestingly, this particular SFI mutation decreased transactivation of TLX1, a transcription factor essential for murine spleen development.
Additionally, the SF1 mutation decreased expression of steroidogenic genes, without affecting synergistic SF-1 and sex-determining region Y (SRY) coactivation of the testis development gene SOX9.
This study indicates that SF-1 is required for both steroidogenesis and spleen development in humans.