Renal interstitial cells to the rescue

(Zebra)fishing for nephrogenesis genes

Kidney disease is a devastating condition affecting millions of people worldwide, where over 100,000 patients in the United States alone remain waiting for a lifesaving organ transplant. Concomitant with a surge in personalized medicine, single-gene mutations, and polygenic risk alleles have been brought to the forefront as core causes of a spectrum of renal disorders. With the increasing prevalence of kidney disease, it is imperative to make substantial strides in the field of kidney genetics. Nephrons, the core functional units of the kidney, are epithelial tubules that act as gatekeepers of body homeostasis by absorbing and secreting ions, water, and small molecules to filter the blood. Each nephron contains a series of proximal and distal segments with explicit metabolic functions. The embryonic zebrafish provides an ideal platform to systematically dissect the genetic cues governing kidney development. Here, we review the use of zebrafish to discover nephrogenesis genes.

The amazing axolotl: robust kidney regeneration following acute kidney injury

The incidence of kidney disease from acute and chronic conditions continues to escalate worldwide. Interventions to replace renal function after organ failure remain limited to dialysis or transplantation, as human kidneys exhibit a limited capacity to repair damaged cells or regenerate new ones. In contrast, animals ranging from flies to fishes and even some mammals like the spiny mouse exhibit innate abilities to regenerate their kidney cells following injury. Now, a recent study has illuminated how the Mexican salamander, Ambystoma mexicanum, most commonly known as the axolotl, possesses a kidney with remarkable similarity to humans, which can robustly regenerate following acute chemical damage. These discoveries position the axolotl as a new model that can be used to advance our understanding about the fundamental mechanisms of kidney regeneration.