A team of European researchers recently discovered how the regulation of progenitor cell proliferation and differentiation in highly regenerative tissues, such as skin and muscles, spins out of control. (Nov. '09)
Whenever lamin mutations occur, the regulation of progenitor cell proliferation and differentiation in highly regenerative tissues, such as skin and muscles, spins out of control. This is the startling discovery of Eurolaminopathies, the EU project headed by Professor Roland Foisner from the University of Vienna, which focused on that group of inherited diseases including muscular dystrophy, cardiomyopathy, lipodistrophy and premature aging.
The outer part of a cell’s nucleus is called the nuclear envelope. The inner layer of this envelope is known as the “peripheral nuclear lamina”, containing the protein lamin A. Until recently, lamin A was regarded as a structural component of vertebrate cells; the Eurolaminopathies project showed it actually plays a major role in the regulation of the cell cycle, which is a crucial process during embryonic development, tissue homeostasis and regeneration in adult organisms.
So far, the molecular mechanisms of these diseases had been poorly understood. But now this new evidence points to the fact that lamins play a key role in transcriptional control. Human skin and muscles are tissues that have to be constantly regenerated to function properly. One of the very intriguing conclusions of the Eurolaminopathies project is that similar regenerative processes are also relevant in the normal human ageing process. Lamins have to be included among the key players in controlling the process of cellular ageing, since a disturbance in lamin structure causes several forms of premature ageing.
In adult organisms, lamin A seems to affect, specifically, cell proliferation and differentiation of progenitor cells which are responsible for producing new tissue-specific cells in highly regenerative tissues. To get to this conclusion, Professor Foisner and his team deleted a specific binding partner of lamin A, which determines the localization of lamin A in the nucleus. Loss of this binding caused the misplacement of lamin A, which impaired cell cycle arrest and caused hyperproliferation of progenitor cells and tissue hyperplasia, which causes the cells to divide constantly.
Scientists are just beginning, Professor Foisner said, “to understand some of the functions of lamins in adult stem cells”. More research is required “into the lamin-mediated processes responsible for efficient tissue regeneration” These highly relevant findings are “the prerequisite for the development of new treatments of patients with a laminopathy disorder”, but also a very interesting premise to study the role of lamins in natural ageing, “which has a great scientific and social potential”.
(11 November 2009)