Different effects of long-term and short-term repeated restraints on the hematopoietic stem cells in mice / 生理学报

Humans with chronic psychological stress are prone to develop multiple disorders of body function including impairment of immune system. Chronic psychological stress has been reported to have negative effects on body immune system. However, the underlying mechanisms have not been clearly demonstrated. All immune cells are derived from hematopoietic stem cells (HSC) in the bone marrow, including myeloid cells which comprise the innate immunity as a pivotal component. In this study, to explore the effects of chronic psychological stress on HSC and myeloid cells, different repeated restraint sessions were applied, including long-term mild restraint in which mice were individually subjected to a 2 h restraint session twice daily (morning and afternoon/between 9:00 and 17:00) for 4 weeks, and short-term vigorous restraint in which mice were individually subjected to a 16 h restraint session (from 17:00 to 9:00 next day) for 5 days. At the end of restraint, mice were sacrificed and the total cell numbers in the bone marrow and peripheral blood were measured by cell counting. The proportions and absolute numbers of HSC (LinCD117Sca1CD150CD48) and myeloid cells (CD11bLy6C) were detected by fluorescence activated cell sorting (FACS) analysis. Proliferation of HSC was measured by BrdU incorporation assay. The results indicated that the absolute number of HSC was increased upon long-term mild restraint, but was decreased upon short-term vigorous restraint with impaired proliferation. Both long-term mild restraint and short-term vigorous restraint led to the accumulation of CD11bLy6C cells in the bone marrow as well as in the peripheral blood, as indicated by the absolute cell numbers. Taken together, long-term chronic stress led to increased ratio and absolute number of HSC in mice, while short-term stress had opposite effects, which suggests that stress-induced accumulation of CD11bLy6C myeloid cells might not result from increased number of HSC.

Effects of NEDD8 covalent modification inhibitor MLN4924 on proliferation and apoptosis of human ovarian cancer cell line SKOV3 / 中国免疫学杂志

Objective:To explore the effects of neural precursor cell-expressed developmentally down regulated 8(NEDD8) covalent modification on ovarian cancer cell proliferation and apoptosis,and the possible underlying mechanisms.Methods:Use different concentrations of MLN4924 (0,0.125,0.25,0.5 mol/L) and human ovarian cancer cell line SKOV3,the expression levels of PAR3, HER2,Neddylated-cullins,P-IκBα were detected by Western blot and the secretion of IL-6 was measured by ELISA after 4 h treatment.The cell proliferation was determined by CCK-8 staining and the cell cycle and apoptosis were analyzed by flow cytometry after 72 h treatment.Results:MLN4924 inhibits the proliferation of SKOV3 cells in a dose-dependent manner,which is associated with reduced IL-6 secretion.Western blot revealed that MLN4924 dose-dependently inhibits the neddylation of cullins(reduced neddylated-cullins) and induced the accumulation of P-IκBα,whereas the expression levels of PARs and HER2 remained largely unchanged.At the same time MLN4924 dose-dependently induced cell cycle prove at S phase and the formation of a large number of tetraploids.Furthermore,apoptosis increased with the dose of MLN4924.Conclusion:NEDD8 covalent modification specific inhibitor MLN4924 can significantly inhibit the proliferation of SKOV3 cells and induce cell cycle arrest and apoptosis.The above inhibitory effects may partially result from impaired P-IκBα degradation and IL-6 secretion.

Hyperactivation of c-Jun NH(2)-terminal protein kinase contributes to the proliferation of B lymphoma cells / 中国实验血液学杂志

This study was purposed to explore the effect of hyperactivation of c-Jun NH(2)-terminal protein kinase (JNK) on the proliferation of B lymphoma cells. The human B lymphoma cell lines Daudi and Raji were chosen as research objects. The expression of JNK protein was determined by Western blot. The subcellular localization of JNK protein was detected by immunofluorescence. The cell cycle was analyzed by flow cytometry. The suppressive effect of JNK inhibitor SP600125 on the proliferation of Daudi and Raji cells was assayed by ATPLite method. The results demonstrated that hyperactivation of JNK has been found in Daudi and Raji cells. Immunofluorescence confirmed the aberrant subcellular localization of JNK protein in Daudi and Raji cells. Cell cycle assay revealed that Daudi and Raji cells underwent G(2)-M arrest in the presence of SP600125. Furthermore, Daudi and Raji cells showed significant increase in sub-G(1) population, an indicator of apoptotic cells, with the treatment of JNK inhibitors. These data suggested that JNK inhibitors suppressed the growth of B lymphoma cells via cell cycle arrest and apoptosis. Daudi and Raji cells treated with different concentrations of JNK selective inhibitor SP600125 showed dose-dependent reduction in the growth of Daudi and Raji cells. It is concluded that hyperactivation of JNK enhance the proliferation of Daudi and Raji cells. The aberrant subcellular localization of JNK protein may facilitate the nuclear accumulation of basal JNK activity, which made JNK to be a potential target to treat human B lymphoma.