Advancement in medicine and healthcare has increased the average life span of people all over the world. This means a majority of the population is going to age, and be susceptible to the diseases and disorders related to aging. Aging is an inevitable physiological change happening over time. Aging of the brain is associated with a reduction in cognition, significantly affecting subject´s ability to live a normal independent life. It also poses an enormous economic burden on aged subjects and their families (1). It is imperative to find an effective therapy for aging associated cognitive impairments.
Insulin-like growth factor-1 (IGF-1) is a signaling protein that plays an important role in regulating learning and memory, and age-related diseases. We see a decrease in the levels of IGF-1 in blood circulation, cerebrospinal fluid and brain (hippocampal) tissue in aged rodents. Moreover, the decline in cognition is reversible with IGF-1 supplementation (2).
Most of the work regarding IGF-1 involves investigations in neurons. However, other cells which are responsible for regulating many functions vital for the normal functioning of the brain are largely ignored. Our lab focuses on investigating the effects of astrocyte-derived IGF-1 on learning and memory. Astrocytes are glial cells involved in the release of several key growth factors, neurotransmitters like glutamate, and molecules like ATP, that are responsible for signal transduction processes (3). Thus, astrocytes are not merely a sidekick, but are responsible for maintaining the microenvironment that supports and nurtures neurons. Disruption of astrocyte´s signaling could affect neurons and ultimately cognition. Astrocytes stained using immunocytochemistry can be seen in the figure alongside (from http://www.abcam.com).
My research focuses on investigating the effects of loss of IGF-1 signaling in astrocytes due to aging, and its effects on the release of neurotransmitters, ATP, and ultimately on learning and memory. We also examine what aspects of cognition are regulated by IGF-1 and astrocytes. The findings will help answer some of the important questions about IGF-1 signaling, astrocytes and cognitive decline during aging.
- Ortman, B. J. M., Velkoff, V. a., & Hogan, H. (2014). An aging nation: The older population in the United States. Proc. Economics and Statistics Administration, US Department of Commerce (Vol. 1964). Retrieved from https://www.census.gov/prod/2014pubs/p25-1140.pdf
- Ashpole, N. M., Sanders, J. E., Hodges, E. L., Yan, H., & Sonntag, W. E. (2015). Growth hormone, insulin-like growth factor-1 and the aging brain. Experimental Gerontology. 68:76-81.
- Gibbs, M. E., Hutchinson, D., & Hertz, L. (2008). Astrocytic involvement in learning and memory consolidation. Neuroscience and Biobehavioral Reviews. 32(5):927-44.
Department of Biomolecular Sciences
University of Mississippi