TY - JOUR
T1 - N-acetylcysteine increases the frequency of bone marrow Pro-B/pre-B cells, but does not reverse cigarette smoking-induced loss of this subset
AU - Palmer, Victoria L.
AU - Kassmeier, Michele D.
AU - Willcockson, James
AU - Akhter, Mohammed P.
AU - Cullen, Diane M.
AU - Swanson, Patrick C.
PY - 2011/9/16
Y1 - 2011/9/16
N2 - Background: We previously showed that mice exposed to cigarette smoke for three weeks exhibit loss of bone marrow B cells at the Pro-B-to-pre-B cell transition, but the reason for this is unclear. The antioxidant N-acetylcysteine (NAC), a glutathione precursor, has been used as a chemopreventive agent to reduce adverse effects of cigarette smoke exposure on lung function. Here we determined whether smoke exposure impairs B cell development by inducing cell cycle arrest or apoptosis, and whether NAC treatment prevents smoking-induced loss of developing B cells. Methodology/Principal Findings: Groups of normal mice were either exposed to filtered room air or cigarette smoke with or without concomitant NAC treatment for 5 days/week for three weeks. Bone marrow B cell developmental subsets were enumerated, and sorted pro-B (B220 +CD43 +) and pre-B (B220 +CD43 -) cell fractions were analyzed for cell cycle status and the percentage of apoptotic cells. We find that, compared to sham controls, smoke-exposed mice have ~60% fewer pro-B/pre-B cells, regardless of NAC treatment. Interestingly, NAC-treated mice show a 21-38% increase in total bone marrow cellularity and lymphocyte frequency and about a 2-fold increase in the pro-B/pre-B cell subset, compared to sham-treated controls. No significant smoking- or NAC-dependent differences were detected in frequency of apoptotic cells or the percentage cells in the G1, S, or G2 phases of the cycle. Conclusions/Significance: The failure of NAC treatment to prevent smoking-induced loss of bone marrow pre-B cells suggests that oxidative stress is not directly responsible for this loss. The unexpected expansion of the pro-B/pre-B cell subset in response to NAC treatment suggests oxidative stress normally contributes to cell loss at this developmental stage, and also reveals a potential side effect of therapeutic administration of NAC to prevent smoking-induced loss of lung function.
AB - Background: We previously showed that mice exposed to cigarette smoke for three weeks exhibit loss of bone marrow B cells at the Pro-B-to-pre-B cell transition, but the reason for this is unclear. The antioxidant N-acetylcysteine (NAC), a glutathione precursor, has been used as a chemopreventive agent to reduce adverse effects of cigarette smoke exposure on lung function. Here we determined whether smoke exposure impairs B cell development by inducing cell cycle arrest or apoptosis, and whether NAC treatment prevents smoking-induced loss of developing B cells. Methodology/Principal Findings: Groups of normal mice were either exposed to filtered room air or cigarette smoke with or without concomitant NAC treatment for 5 days/week for three weeks. Bone marrow B cell developmental subsets were enumerated, and sorted pro-B (B220 +CD43 +) and pre-B (B220 +CD43 -) cell fractions were analyzed for cell cycle status and the percentage of apoptotic cells. We find that, compared to sham controls, smoke-exposed mice have ~60% fewer pro-B/pre-B cells, regardless of NAC treatment. Interestingly, NAC-treated mice show a 21-38% increase in total bone marrow cellularity and lymphocyte frequency and about a 2-fold increase in the pro-B/pre-B cell subset, compared to sham-treated controls. No significant smoking- or NAC-dependent differences were detected in frequency of apoptotic cells or the percentage cells in the G1, S, or G2 phases of the cycle. Conclusions/Significance: The failure of NAC treatment to prevent smoking-induced loss of bone marrow pre-B cells suggests that oxidative stress is not directly responsible for this loss. The unexpected expansion of the pro-B/pre-B cell subset in response to NAC treatment suggests oxidative stress normally contributes to cell loss at this developmental stage, and also reveals a potential side effect of therapeutic administration of NAC to prevent smoking-induced loss of lung function.
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U2 - 10.1371/journal.pone.0024804
DO - 10.1371/journal.pone.0024804
M3 - Article
C2 - 21949757
AN - SCOPUS:80052852750
VL - 6
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 9
M1 - e24804
ER -