AP52925

The Immune System and Aging

Researchers have discovered why the immune system age with time. Our textbook, Chapter 17, it tell us that the average life expectancy these days is 75 years for males and 80 years for females. Dr.Emmanuelle Passegué, a professor of medicine and a member of the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF, and his team published their findings online, July 30, 2014 in the journal //Nature.// Dr. Passegué stated, "We have found the cellular mechanism responsible for the inability of blood-forming cells to maintain blood production over time in an old organism, and have identified molecular defects that could be restored for rejuvenation therapies." He and his team of researchers published their new findings online, July 30, 2014 in the journal //Nature.// Blood and immune cells are short-lived and need to be replenished. Researchers found a lack of specific protein components needed to form a molecular machine called the mini-chromosome maintenance helicase in old blood-forming stem cells. This machine unwinds double-stranded DNA so that the cell's genetic material can be duplicated and allocated to daughter cells later in cell division. In the study, stem cells were stressed by the loss of activity of the machine and were at heightened risk for DNA damage and death when forced to divide. Passegué also stated, "The decline of stem-cell function is a big part of age-related problems. Achieving longer lives relies in part on achieving a better understanding of why stem cells are not able to maintain optimal functioning." Researchers hope to develop a drug that prevents the loss of the helicase components.

References: Johanna Flach, Sietske T. Bakker, Mary Mohrin, Pauline C. Conroy, Eric M. Pietras, Damien Reynaud, Silvia Alvarez, Morgan E. Diolaiti, Fernando Ugarte, E. Camilla Forsberg, Michelle M. Le Beau, Bradley A. Stohr, Juan Méndez, Ciaran G. Morrison, Emmanuelle Passegué. **Replication stress is a potent driver of functional decline in ageing haematopoietic stem cells**. //Nature//, 2014; DOI: 10.1038/nature13619

University of California, San Francisco (UCSF). "Key to aging immune system: Discovery of DNA replication problem." ScienceDaily. ScienceDaily, 31 July 2014. .

Boyd, Denise Roberts., and Helen L. Bee. //Lifespan Development//. Sixth ed. Boston: Pearson Allyn & Bacon, 2012. Print.

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