Differential stem cell aging kinetics in Hutchinson-Gilford progeria syndrome and Werner syndrome

Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) are two of the best characterized human progeroid syndromes. HGPS is caused by a point mutation in lamin A (LMNA) gene, resulting in the production of a truncated protein product-progerin. WS is caused by mutations in WRN gene, encoding a loss-of-function RecQ DNA helicase. Here, by gene editing we created isogenic human embryonic stem cells (ESCs) with heterozygous (G608G/+) or homozygous (G608G/G608G) LMNA mutation and biallelic WRN knockout, for modeling HGPS and WS pathogenesis, respectively. While ESCs and endothelial cells (ECs) did not present any features of premature senescence, HGPS- and WS-mesenchymal stem cells (MSCs) showed aging-associated phenotypes with different kinetics. WS-MSCs had early-onset mild premature aging phenotypes while HGPS-MSCs exhibited late-onset acute premature aging characterisitcs. Taken together, our study compares and contrasts the distinct pathologies underpinning the two premature aging disorders, and provides reliable stem-cell based models to identify new therapeutic strategies for pathological and physiological aging.

Establishment and Optimization of Culture Technique for Enteroids / 胃肠病学

Background:Enteroids are considered to be the best tool for studies on intestinal epithelium in vitro and have a widely application prospects,however,there are no associated reports in China. Aims:To establish and optimize the culture technique for enteroids and provide a fantastic platform for the basic research of small intestinal epithelial cells in China. Methods:L-WRN cells were cultured routinely and the conditioned medium with different concentrations of fetal bovine serum(FBS)was collected. Six to eight weeks old C57BL/ 6 mice were sacrificed and 15 cm small intestine from the terminal ileum was removed and cut longitudinally. Crypts were digested with EDTA and then collected and embedded in Matrigel? Matrix;after polymerization of Matrigel? Matrix,L-WRN conditioned medium at different concentration gradient was added. The budding ratio and length of buds were measured dynamically under microscope. The enteroids were re-embedded for subculture when certain length of buds was reached. Results:Compared with L-WRN conditioned medium containing 20% FBS,the conditioned medium containing 10% FBS was more favorable for enteroids culture in vitro. When conditioned medium accounted for 10% ,15% ,20% ,25% or 30% of the mixed medium,they all promoted the growth of enteroids and the 15% one seemed to yield better result. Conclusions:An enteroids culture technique was successfully established for the first time in China. When the L-WRN conditioned medium containing 10% FBS accounts for 15% of the mixed medium,it might promote budding better than the others.

A case of atypical Werner syndrome without WRN gene mutations / 대한내과학회지

Werner syndrome is a rare autosomal recessive, hereditary disease that demonstrates progeroid features and has characteristic WRN gene mutations. Atypical Werner syndrome refers to a small subset of individuals who produce the normal WRN protein, but show some signs and symptoms that sufficiently overlap with Werner syndrome. Recently, we experienced a case of atypical Werner syndrome. A 43-year-old woman was admitted to our hospital due to being severely underweight. She had an operative history of cataracts in both eyes and had suffered from multiple skin ulcers, deafness, and vision loss. Physical examination revealed short stature, low body weight, flat feet, and a scleroderma-like skin change. Laboratory and clinical tests showed that the patient had diabetes mellitus, osteoporosis, and premature atherosclerotic features. Her clinical presentation and laboratory findings were consistent with Werner syndrome. We performed a WRN, LMNA gene sequence analysis, but no mutations were detected. The patient was diagnosed with atypical Werner syndrome.