Usha Ponnappan, Ph.D. is an Associate Professor in the Department of Microbiology & Immunology at UAMS. Dr. Ponnappan is studying the biochemical and molecular basis of immune dysregulation that accompanies aging. Her long-term research objective is to identify changes in immune regulation relevant to the initiation and progression of geriatric diseases.
Declining immune function is a hallmark of aging and manifests itself as increased susceptibility to infections, a greater risk of malignancies and increased incidence of autoimmune diseases. Although these age-related declines have been well documented, the fundamental basis of immune senescence remains to be fully defined. Dr. Ponnappan’s studies have demonstrated a significant decline in the regulation of transcription factor NFkB and proteasomal function associated with T lymphocytes in the elderly. These key findings are likely to shed light on diverse age-related processes, such as T-cell repertoire skewing, accumulation of aberrant proteins and protein turn over in the elderly, multi-ubiquitinated protein deposits in senile dementia, lowered responses to viral antigens and defects in cell cycle regulation during proliferation and apoptosis in the elderly.
S. Ponnappan, G. Uken-Trebilcock, M. Lindquist and U. Ponnappan. Tyrosine phosphorylation-dependent activation of NFkB is compromised in T cells
from the elderly. (2004) Experimental Gerontology 39, 559-566.
L.S.F. Soderberg, U. Ponnappan, A. Roy, R. Schafer, and J.B. Barnett. Production of macrophage IL-1beta was inhibited both at the levels of transcription and maturation by caspase-1 following inhalation exposure to isobutyl nitrite. (2004) Tox. Lett. (In Press).
W. Burks, U. Ponnappan, L. Pons, P. Simpson, R. A. Hall, G. Cockrell, M. West, H. A. Sampson, and R. Helm. Soy Immunotherapy for Peanut Allergic Mice: Modulation of the Peanut Allergic Response. (2004) J.Clin.Allergy and Immunol. 2004 (in press).
U. Ponnappan, F.E. Yull and Soderberg, L.S.F. Inhaled isobutyl nitrite inhibited macrophage inducible nitric oxide by blocking NFkB signaling and promoting degradation of inducible nitric oxide synthase-2. (2004) Tox. Lett. (in press).
S. Ponnappan, S. Cullen and U. Ponnappan. Constitutive degradation of I kappa B alpha in primary human T lymphocytes is mediated by calpain and remains intact during aging. (submitted).
Age-associated alterations in proteasomal subunits may underlie defect in function during aging. S.Ponnappan and U.Ponnappan, Proceedings of the international conference in immunology 2004, (Submitted).
