Model of human aging: Recent findings on Werner’s and Hutchinson-Gilford progeria syndromes

Abstract

Shian-ling Ding1, Chen-Yang Shen2,3,41Department of Nursing, Kang-Ning Junior College of Medical Care and Management, Taipei, Taiwan; 2Institute of Biomedical Sciences, and 3Life Science Library, Academia Sinica, Taipei, Taiwan; 4Graduate Institute of Environmental Science, China Medical University, Taichong, TaiwanAbstract: The molecular mechanisms involved in human aging are complicated. Two progeria syndromes, Werner’s syndrome (WS) and Hutchinson-Gilford progeria syndrome (HGPS), characterized by clinical features mimicking physiological aging at an early age, provide insights into the mechanisms of natural aging. Based on recent findings on WS and HGPS, we suggest a model of human aging. Human aging can be triggered by two main mechanisms, telomere shortening and DNA damage. In telomere-dependent aging, telomere shortening and dysfunction may lead to DNA damage responses which induce cellular senescence. In DNA damage-initiated aging, DNA damage accumulates, along with DNA repair deficiencies, resulting in genomic instability and accelerated cellular senescence. In addition, aging due to both mechanisms (DNA damage and telomere shortening) is strongly dependent on p53 status. These two mechanisms can also act cooperatively to increase the overall level of genomic instability, triggering the onset of human aging phenotypes.Keywords: human aging, Hutchinson-Gilford Progeria syndrome, Werner syndrome