This Week's Presentations
Monday, 9. May, 2005
Phillips 267 at 4:00 pm
Why Does Hair Turn Gray?
Presented by Nick Cartwright
9. May, 2005
Abstract:
Hair graying is the most obvious sign of aging in humans, yet its mechanism is largely unknown. Here, the group used melanocyte-tagged transgenic mice and aging human hair follicles to demonstrate that hair graying is caused by defective self-maintenance of melanocyte stem cells.[1] This process is accelerated dramatically with Bcl2 deficiency, which causes selective apoptosis of melanocyte stem cells, but not of differentiated melanocytes, within the niche at their entry into the dormant state. Furthermore, physiologic aging of melanocyte stem cells was associated with ectopic pigmentation or differentiation within the niche, a process accelerated by mutation of the melanocyte master transcriptional regulator Mitf.
'Heart-Renewing' Cells?
Presented by Miranda Lange
9. May, 2005
Abstract:
Until now there has been little evidence for native cardiac precursor cells in the postnatal heart. The identification of isl1+ cardiac progenitors in the postnatal rat, mouse, and human myocardium represents a large step in the biological understanding about the origin and fate of the cycling myocytes detected in the normal pathological heart. [1] Furthermore, the discovery of these native cardioblasts represents a genetically based system to identify steps in cardiac cell lineage formation and maturation in heart development and disease. The existence of such ‘heart-renewing’ stem cells capable of committing to the myogenic lineage conclusively dispels the notion of the heart as a terminally differentiated organ without self-renewal potential.