Karima Djabali, PhD
Dr. Djabali's research focuses on the area of cellular aging in normal and diseased states. One of her research objectives is to define the molecular and cellular pathogenesis of the premature aging disease Hutchinson Gilford Progeria Syndrome (HGPS).
Hutchinson-Gilford progeria syndrome (HGPS, OMIM 176670) is a rare disorder that is characterized by segmental accelerated aging and early death, frequently from coronary artery disease. Patients with HGPS present with very characteristic features: short stature, alopecia, sculpted nose, prominent scalp veins, loss of subcutaneous fat, and prominent joints. Mutations in the LMNA gene, encoding lamin A, are responsible for this syndrome; as such, HGPS belongs to the super-family of laminopathies. The common HGPS mutation corresponds to a de novo single-base pair substitution, G608G (GGC>GGT), within exon 11 of LMNA gene. This mutation results in the deletion of 50 amino acids from the carboxyl-terminal tail of prelamin A; the truncated protein is called progerin. The lamins, and lamin A in particular, are nuclear structural proteins that bind many important cellular regulators and may play a role in regulating the accessibility of those factors to fulfill their function. The progerin mutation appears to elicit a tissue specific pattern of alterations, involving primary tissues with renewal potency: muscle, skin, and bone.
At the cellular level, the mutant protein is abnormally processed and appears to induce alterations within the nucleus and genomic instability that leads the cell to withdraw from the cell cycle, a process called cellular senescence. A growing population of senescent cells in vivo would result in the loss of tissue integrity and function that is a hallmark of aging.
Determining the pathogenesis of the truncated lamin A in HGPS syndrome is being addressed in Dr. Djabali's lab by a combination of molecular, cellular biology and proteomics approaches. These studies will provide the basic data needed to lead to potential treatments for Progeria patients and increase our knowledge about the biology of normal aging.
Department of Dermatology BSRG, Vanderbilt Clinic, 15-204
630 West 168th Street
New York, NY 10032