A review integrates twenty years of research on Hutchinson-Gilford progeria, a rare disease that causes children to age and die at an average age of 14.5 years, into a single causal chain: one nuclear defect destroys the cell, the tissue, and the entire organism step by step
A review integrates twenty years of research on Hutchinson-Gilford progeria, a rare disease that causes children to age and die at an average age of 14.5 years, into a single causal chain: one nuclear defect destroys the cell, the tissue, and the entire organism step by step
Karima Djabali, a professor at the Technical University of Munich, published a review of twenty years of progeria research in Mechanisms of Ageing and Development on September 17. For the first time, all mechanisms of the disease are organized into four levels (nucleus, cell, tissue, organism) rather than presented as a list of independent disruptions, and the strength of evidence is assessed at each level, from experimentally confirmed findings to a model not yet proven in full.
Progeria is caused by a single mutation in the LMNA gene. The normal protein lamin A lines the inner surface of the nuclear envelope and maintains its shape. A short lipid tail is needed only during protein assembly and is then cleaved off. Because of the mutation, progerin, a truncated version of lamin A, retains this tail permanently, and the protein binds irreversibly to the nuclear envelope.
Cells carrying the mutation appear deformed under the microscope but divide and function normally in quiescence. The defect manifests only after heat shock: healthy cells recover quickly, while cells with progerin do not. Nuclear pores, the openings in the nuclear envelope that allow molecular exchange, behave the same way: they assemble correctly right after cell division but gradually cluster together as the cell ages.
Progerin does not reach a steady-state level. It accumulates with cell age, particularly in blood vessels, where cells persist for weeks. This explains why the heart and vasculature suffer most severely even though the gene is expressed uniformly throughout the body. The same progerin appears in small amounts during normal aging, in aging skin and, according to recent findings, in damaged vessels in chronic kidney disease.
At the cellular level, nuclear damage impairs the clearance of damaged proteins, and weakened clearance accelerates accumulation of the same progerin, closing a vicious cycle. Sulforaphane, a compound from broccoli, and rapamycin restore this clearance and alleviate some of the cellular symptoms, though they do not eliminate them entirely.
At the tissue level, a second cycle of the same kind operates: damaged cells senesce and secrete inflammatory signals, and the inflammation accelerates senescence in neighboring cells. Baricitinib, a drug already approved for other conditions, suppresses this signaling. Combined with lonafarnib, it extended the lifespan of mice more than either drug alone.
Lonafarnib, the only progeria drug with proven survival benefit (approved in the United States in 2020), acts at the nuclear level: it weakens the attachment of progerin to the nuclear envelope. Djabali proposes adding baricitinib and sulforaphane to address the tissue and cellular levels while a more radical approach, genome editing, matures. Genome editing already corrects the mutation itself and extends the lifespan of mice, and a technique that bypasses the mutation altogether raised their lifespan 2.4-fold. Neither technology is yet available to children.
The key experiments on the nucleus and the cell come from her laboratory, which has studied progeria since 2002; the tissue and organism findings are from independent groups. She completed her doctoral work under Nobel laureate Günter Blobel, who discovered the signals governing protein transport within the cell, and her finding on nuclear pore clustering continues that line of research.
"HGPS is not a copy of physiological aging but a genetically defined system that shows how sustained nuclear stress progressively dismantles the organism's conserved adaptive networks," Djabali writes.