Date Submitted
3-31-2023
Faculty Advisor
Ehab Sarsour, Ph.D.
Second Faculty Advisor
Asma Zaidi, Ph.D.
Third Faculty Advisor
Pratima Singh, M.D.
Abstract
According to the United States Census Bureau, there will be a 10% increase in the number of individuals 65 years of age and older by 2050. Unfortunately, increases in longevity are also associated with increased risk factors for numerous health issues and decreased effectiveness of medical interventions. Aging cells lose their ability to renew and repair. The purpose of this study is to determine if age-associated changes in lipid signaling regulate the health of aging normal human fibroblasts (NHFs). The hypothesis is that age-associated changes in lipid metabolism contribute to a pro-inflammatory phenotype and impaired wound healing in aging NHFs. RNA sequencing of primary cultures of NHFs from healthy donors ranked lipid metabolism as the top metabolic process that is altered during aging. Results from immunoblot analysis show significant decreases (greater than 50%) in the protein levels of G0-G1 Switch 2 (G0S2), a negative regulator of the lipolytic enzyme, adipose triglyceride lipase (ATGL) in older NHFs, whereas no significant difference was observed in the protein levels of ATGL or its co-activator Comparative Gene Identification-58 (CGI-58). Using BODIPY C11 lipid peroxidation sensor to measure the ratio of lipid peroxides to neutral lipids, results showed an age-associated increase in lipid peroxidation. Using wound healing assays, results showed that NHFs from older individuals have impaired wound closing ability when compared to those from younger individuals. Additionally, cytokine arrays revealed significantly increased inflammatory cytokines, including IL-6, IL-8, and CCL5, in older NHFs compared to young. Overall, these results indicate that G0S2-dependent lipolytic signaling contributes to age-related impairment in wound healing and pro-inflammatory phenotype. The intervention of the G0S2-ATGL pathway is an attractive and novel avenue to mitigate the age-associated decline in the regenerative efficacy of tissues
