Proteostasis is an integral component of healthy aging. In most metazoans, protein quality declines during aging, resulting in accrual of damaged or self-aggregating cytotoxic proteins, linked to several age-associated diseases (e.g., Alzheimer's Disease, Parkinson's Disease) and pathology (e.g., sarcopenia, cataracts). The mouse-sized naked mole-rat [NMRs] lives ~5 times longer than expected based on body size, and despite detected high levels of oxidative damage even at a young age, maintain good health for most of their long lives. Like other long-lived animal models, both in vivo and in vitro studies reveal that NMRs are resistant to a broad spectrum of environmental stressors. Collectively these findings suggest that NMRs possess efficient mechanisms to maintain protein quality. Our research has previously shown that this is attributed in part to altered proteasome forms and subcellular location. However, changes in proteasome-related molecular chaperone activity that assists in the transport of damaged proteins into the proteasome may also play a role in this decline. Here we examine key proteasome-related molecular chaperones [HSPs] and the heat-shock factor 1 [HSF1] transcription factor in the brain, heart, liver, spleen, kidney, testes, and quadriceps leg muscle in mice and NMRs. HSP25 both showed higher levels of protein in NMRs compared to mice in all the tissues examined. Hence we measured HSP25 protein content in seven rodents with ages ranging from four to 32 years in both liver and muscle. This comparison resulted in a significant correlation with longevity suggesting that HSP25 may play a key role in age-related maintenance of protein homeostasis in long-lived animals. A review of the literature suggested that HSP25 was involved in a number of cellular systems or responses including heat stress, proteasome activity, autophagy, inflammatory response, and cell structure stabilization all to prevent apoptosis in the cell. Thus, we test the overall hypothesis that HSP25 mediates the trafficking of proteins to different protein degradative pathways based upon the stress-state of the cell to maintain homeostasis, and this action is an integral component responsible for increasing longevity and healthspan in long-lived species.

Public Health Relevance

The protein HSP25 has been implicated in a number of pathways critical to healthspan and longevity. In this study we attempt to discover how this protein works to act a bridge or traffic cop between these pathways to maintain working proteins during stress and aging in a cell or whole animal. These findings could suggest individualized therapy for age-associated diseases such as Alzheimer's and Parkinson's diseases and aging conditions such as sarcopenia and cataracts where protein malfunctions are major contributors to the diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Transition Award (R00)
Project #
5R00AG049940-05
Application #
9686496
Study Section
Special Emphasis Panel (NSS)
Program Officer
Velazquez, Jose M
Project Start
2015-08-15
Project End
2020-03-31
Budget Start
2019-04-01
Budget End
2020-03-31
Support Year
5
Fiscal Year
2019
Total Cost
Indirect Cost
Name
University of Texas Health Science Center
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Rodriguez, Karl A; Valentine, Joseph M; Kramer, David A et al. (2016) Determinants of rodent longevity in the chaperone-protein degradation network. Cell Stress Chaperones 21:453-66