Signaling molecule crucial to stem cell reprogramming

PUBLIC RELEASE DATE:

20-Nov-2014

Contact: Scott LaFee slafee@ucsd.edu 619-543-5232 University of California - San Diego @UCSanDiego

While investigating a rare genetic disorder, researchers at the University of California, San Diego School of Medicine have discovered that a ubiquitous signaling molecule is crucial to cellular reprogramming, a finding with significant implications for stem cell-based regenerative medicine, wound repair therapies and potential cancer treatments.

The findings are published in the Nov. 20 online issue of Cell Reports.

Karl Willert, PhD, assistant professor in the Department of Cellular and Molecular Medicine, and colleagues were attempting to use induced pluripotent stem cells (iPSC) to create a "disease-in-a-dish" model for focal dermal hypoplasia (FDH), a rare inherited disorder caused by mutations in a gene called PORCN. Study co-authors V. Reid Sutton and Ignatia Van den Veyver at Baylor College of Medicine had published the observation that PORCN mutations underlie FDH in humans in 2007.

FDH is characterized by skin abnormalities such as streaks of very thin skin or different shades, clusters of visible veins and wartlike growths. Many individuals with FDH also suffer from hand and foot abnormalities and distinct facial features. The condition is also known as Goltz syndrome after Robert Goltz, who first described it in the 1960s. Goltz spent the last portion of his career as a professor at UC San Diego School of Medicine. He retired in 2004 and passed away earlier this year.

To their surprise, Willert and colleagues discovered that attempts to reprogram FDH fibroblasts or skin cells with the requisite PORCN mutation into iPSCs failed using standard methods, but succeeded when they added WNT proteins - a family of highly conserved signaling molecules that regulate cell-to-cell interactions during embryogenesis.

"WNT signaling is ubiquitous," said Willert. "Every cell expresses one or more WNT genes and every cell is able to receive WNT signals. Individual cells in a dish can grow and divide without WNT, but in an organism, WNT is critical for cell-cell communication so that cells distinguish themselves from neighbors and thus generate distinct tissues, organs and body parts."

WNT signaling is also critical in limb regeneration (in some organisms) and tissue repair.

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Signaling molecule crucial to stem cell reprogramming