B cell precursors in senescent mice exhibit decreased recruitment into proliferative compartments and altered expression of Bcl-2 family members.
In vitro, aged pro-B cells generally exhibit limited expansion in response to IL-7 when compared to young pro-B cells. CFSE-labeling in vitro indicated that aged mice have a lower frequency of pro-B cells which are capable of undergoing extensive proliferation upon stimulation with exogenous IL-7. Protein levels of the survival molecule Bcl-x(L) were consistently reduced in IL-7 expanded aged pro-B cells. Levels of both Bcl-2 and Baxalpha proteins were variable in aged B cell precursors. The expansion of aged pro-B cells in response to IL-7 in vitro correlated inversely with the ratio of the pro-apoptotic protein Baxalpha to the survival protein Bcl-2. Expansion of aged pro-B cells in vitro is likely dictated by both recruitment of pro-B cells into proliferative compartments and their survival; in aged B cell precursors, the latter is favored by low Baxalpha to Bcl-2 protein ratios.
Sherwood
Erin M
EM
Department of Microbiology and Immunology, University of Miami School of Medicine, P.O. Box 016960 (R138), Miami, FL 33101, USA.
Xu
Wei
W
Riley
Richard L
RL
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001402:B-Lymphocytes / Q000166:cytology*; D002451:Cell Compartmentation / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D016922:Cellular Senescence / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D066298:In Vitro Techniques; D015851:Interleukin-7 / Q000494:pharmacology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D015851:Interleukin-7; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein