The regulation of stem cell aging by Wnt signaling
Shin Fujimaki1,2, Tamami Wakabayashi1, Tohru Takemasa2, Makoto Asashima1 and Tomoko Kuwabara1
1Stem Cell Engineering Research Group, Biotechnology Research Institute for Drug Discovery, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Science City, Ibaraki and 2Physical Education, Health and Sport Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba Science City, Ibaraki, Japan
Offprint requests to: Tomoko Kuwabara, Stem Cell Engineering Research Group, Biotechnology Research Institute for Drug Discovery, Department of Life Science and Biothecnology, National Institute of Advanced Industrial Science and Technology (AIST). Central 5, 1-1-1 Higashi, Tsukuba Science City, Ibaraki, 305-8565, Japan. e-mail: t.warashina@aist.go.jp
Summary. Aging is an inevitable physiological process that leads to the dysfunction of various tissues, and these changes may contribute to certain diseases, and ultimately death. Recent research has discovered biological pathways that promote aging. This review focuses on Wnt signaling, Wnt is a highly conserved secreted signaling molecule that plays an essential role in the development and function of various tissues, and is a notable factor that regulates aging. Although Wnt signaling influences aging in various tissues, its effects are particularly prominent in neuronal tissue and skeletal muscle. In neuronal tissue, neurogenesis is attenuated by the downregulation of Wnt signaling with aging. Skeletal muscle can also become weaker with aging, in a process known as sarcopenia. A notable cause of sarcopenia is the myogenic-to-fibrogenic trans-differentiation of satellite cells by excessive upregulation of Wnt signaling with aging, resulting in the impaired regenerative capacity of aged skeletal muscle. However, exercise is very useful for preventing the age-related alterations in neuronal tissue and skeletal muscle. Upregulation of Wnt signaling is implicated in the positive effects of exercise, resulting in the activation of neurogenesis in adult neuronal tissue and myogenesis in mature skeletal muscle. Although more investigations are required to thoroughly understand age-related changes and their biological mechanisms in a variety of tissues, this review proposes exercise as a useful therapy for the elderly, to prevent the negative effects of aging and maintain their quality of life. Histol Histopathol 30, 1411-1430 (2015)
Key words: Wnt, Aging, Neural stem cells, Satellite cells, Exercise
DOI: 10.14670/HH-11-657