What can tubular progenitor cultures teach us about kidney regeneration?

Cultures of stem or progenitor cells have made critical contributions to the comprehension of tissue regeneration. In the kidney, primary cultures of human tubular progenitors became available only recently and allow dissection of the functional properties of tubular progenitors vs. differentiated tubular epithelia. Toll-like receptor-mediated activation now appears as a previously unknown mechanism of progenitor-mediated tubular regeneration, implying that proinflammatory factors activate regenerative processes in the kidney.