Developmental Biologists Locate Source of Liver Stem Cells

The investigators at Stanford University (Palo Alto, CA, USA) reported in the August 5, 2015, online edition of the journal Nature  that they had identified a population of proliferating and self-renewing cells adjacent to the central vein in the liver lobule that is responsible for the generation of liver cells (hepatocytes). Working with mice, investigators traced the lineage of hepatocytes by determining expression of the Wnt-responsive gene Axin2 (axis inhibition protein 2).These pericentral cells expressed the early liver progenitor marker Tbx3 (T-box 3), were diploid, and thereby differed from mature hepatocytes, which are mostly polyploid. “We have solved a very old problem,” said senior author Dr. Roel Nusse, professor of developmental biology at Stanford University. “We have shown that like other tissues that need to replace lost cells, the liver has stem cells that both proliferate and give rise to mature cells, even in the absence of injury or disease. Differentiated hepatocytes have amplified their chromosomes. That is, the cells have more than the usual two copies of every chromosome. This enables the cells to make more proteins, but it really compromises their ability to divide.” he added.


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