AAS ›› 2013, Vol. 44 ›› Issue (2 ): 189-193.doi: 10.3969/j.issn.0529-1356.2013.02.008

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Oxidation low density lipoprotein promotes aging of mouse hematopoietic stem cells through regulating cell cycles

ZHANG Xian-ping1 ZHANG Gui-hai2 WEN Kun-ming3 LIU JunXU Chu-yan1 WANG Lu1 JIANG Rong1 WANG Ya-ping 1*   

  1. 1.   Laboratory of Stem Cell and Tissue Engineering,Department of Histology and Embryology, Chongqing Medical University,Chongqing 400016,China; 2.Department of Oncology of Zunyi Medical Collage Affiliated Hospital, Guizhou Zunyi 563003, China; 3. Department of Gastroenterological Surgery, Zunyi Medical Collage Affiliated Hospital, Guizhou Zuny 563003, China
  • Received:2012-05-04 Revised:2012-06-12 Online:2013-04-06 Published:2013-04-06

Abstract:

Objective To observe the effect of oxidation low density lipoprotein on aging of hematopoietic stem cells (HSCs) and to reveal the underlying mechanisms that ox-LDL induce the aging of HSCs. Method Mouse HSCs were isolated by magnetic cell sorting with Sca-1 staining. Sca-1+ HSCs were cultured with ox-LDL. Senescence-associated β-galactos idase (Saβ-Gal) staining was used to identify aging HSCs. The capacity of self-renewal of HSCs was evaluated by MTS assay. CFU-Mix cultivation was used to evaluate the potency of differentiation in HSCs. Cell cycles were detected by flow cytometry. The expressions of p16, p21, CDK4 and cyclinD were determined by realtime quantitative PCR (qRT-PCR) and Western blotting analysis. Results Exogenous ox-LDL significantly increased the number of Saβ-Gal staining postive in HSCs, promoted HSCs to arrest at S stage, elevated the ratio of G0/G1 stage , decreased the ratio of S stage and the number of CFU-Mix, and inhibited the proliferation of HSCs compared to HSCs without ox-LDL treatment group. Ox-LDLremarkedly upregulated the expression of p16 and p21 in mRNA and protein levels, decreased the protein expression of CDK4 and cyclinD. There was no significant difference in the protein expression of CDK2 in HSCs. Conclusion ox-LDL may induce mice HSCs aging through upregulating the expressions of p16 and p21, and downregulating CDK4 and cyclinD expressions.

Key words: Aging , Hematopoietic stem cell , Oxidation low density lipoprotein , Cell cycle , Flow cytomety , Mouse