Anti-beta Galactosidase (LacZ) polyclonal antibody

Previous reports have shown that excess calorie intake promotes p53 dependent senescence in mouse adipose tissues. The objective of the current study was to address the mechanism underlying this observation, i.e. adipocyte aging. Using cultured 3T3-L1 cells, we investigated the involvement of energy regulators Sirt1, AMPK, and LKB1 in senescence. Fifteen days post differentiation, Sirt1 knock-down increased senescence-associated beta-galactosidase (SA-beta-Gal) staining by 20-40% (p<0.05, n=12) and both cyclin kinase inhibitor p21(Cip) and chemokine receptor IL8Rb expression by 2-4 fold. ATP and expression of mitochondria Complex 1 were also reduced by 30% and 50%, respectively (p<0.05, n=4). Such energy depletion may have caused the observed increase in AMPK activity, despite LKB1 activity downregulation. This association between Sirt1 and LKB1 activity was confirmed in vivo in mouse adipose tissue. Upregulation of LKB1 activity by expression of the Sirt1-insensitive LKB1-K48R mutant in 3T3- L1 cells completely prevented the senescence-associated changes of Sirt1 knock-down. In addition, cellular senescence, which also occurs in cultured primary human aortic endothelial cells, was largely prevented by ectopic expression of LKB1. These results suggest that LKB1 plays a pivotal role in cellular senescence occurring in adipocytes and other cell types.

Aging is characterized by a progressive deterioration in metabolic functions. The present study aimed to investigate the antagonistic effects of ginsenoside Rg1 (Rg1) on the gamma-ray irradiation-induced aging of mixed hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). C57BL/6 mice were divided into a control group, a gamma-ray irradiation group that served as an aging mouse model, and an Rg1 group. The Rg1 group was treated with Rg1 at dosage of 20 mg/kg/day for 7 days prior to gamma-ray irradiation. The aging mouse model was established by exposing the mice to 6.5-Gy gamma-ray total-body irradiation. Stem cell antigen 1 positive (Sca-1(+)) HSC/HPCs isolated from the mice were examined using a senescence-associated beta-galactosidase (SA-beta-Gal) staining assay. The cell cycle of the HSC/HPCs was examined using flow cytometry. A mixed hematopoietic progenitor cell colony-forming unit (CFU-mix) assay was also conducted. The mRNA and protein expression levels of sirtuin 1 (SIRT1), SIRT3, forkhead box O3 (FOXO3) and superoxide dismutase (SOD2) were evaluated using western blot and reverse transcription-quantitative PCR assays. The results indicated that Rg1 treatment significantly increased white blood cell, red blood cell and platelet counts in peripheral blood compared with those in the gamma-ray irradiation group (P<0.05). However, Rg1 significantly attenuated the senescence of Sca-1(+)HSC/HPCs in the gamma-ray irradiation aging mice model. The proportion of SA-beta-Gal stained HSC/HPCs was significantly decreased and CFU-Mix counts were significantly increased in the Rg1 group compared with the gamma-ray irradiation group (P<0.05). Rg1 significantly increased the mRNA and protein levels of SIRT1, SIRT3, FOXO3 and SOD2 in the Sca-1(+)HSC/HPCs compared with those in the gamma-ray irradiation group (P<0.05). The percentage of Sca-1(+)HSC/HPCs arrested at the G1 phase in the Rg1 group was significantly decreased compared with that in the gamma-ray irradiation group (P<0.05). In conclusion, the present study indicates that Rg1 exerts anti-aging effects via the regulation of SIRT1-FOXO3 and SIRT3-SOD2 signaling pathways, and triggering the progression of Sca-1(+)HSC/HPCs from the G1 phase to the S phase in gamma-ray irradiation-induced aging mice.