Bone Marrow Oxidative Stress and Acquired Lineage-Specific Genotoxicity in Hematopoietic Stem/Progenitor Cells Exposed to 1,4-Benzoquinone

Hematopoietic stem/progenitor cells (HSPCs) are susceptible to benzene-induced genotoxicity. However, little is known about the mechanism of DNA damage response affecting lineage-committed progenitors for myeloid, erythroid, and lymphoid. Here, we investigated the genotoxicity of a benzene metabolite, 1,4-benzoquinone (1,4-BQ), in HSPCs using oxidative stress and lineage-directed approaches. Mouse bone marrow cells (BMCs) were exposed to 1,4-BQ (1.25–12 μM) for 24 h, followed by oxidative stress and genotoxicity assessments. Then, the genotoxicity of 1,4-BQ in lineage-committed progenitors was evaluated using colony forming cell assay following 7–14 days of culture. 1,4-BQ exposure causes significant decreases (p < 0.05) in glutathione level and superoxide dismutase activity, along with significant increases (p < 0.05) in levels of malondialdehyde and protein carbonyls. 1,4-BQ exposure induces DNA damage in BMCs by significantly (p < 0.05) increased percentages of DNA in tail at 7 and 12 μM and tail moment at 12 μM. We found crucial differences in genotoxic susceptibility based on percentages of DNA in tail between lineage-committed progenitors. Myeloid and pre-B lymphoid progenitors appeared to acquire significant DNA damage as compared with the control starting from a low concentration of 1,4-BQ exposure (2.5 µM). In contrast, the erythroid progenitor showed significant damage as compared with the control starting at 5 µM 1,4-BQ. Meanwhile, a significant (p < 0.05) increase in tail moment was only notable at 7 µM and 12 µM 1,4-BQ exposure for all progenitors. Benzene could mediate hematological disorders by promoting bone marrow oxidative stress and lineage-specific genotoxicity targeting HSPCs

Effect of N-acetylcysteine supplementation on oxidative stress-mediated cryoinjury of bone marrow derived-hematopoietic stem cells

Hematopoietic stem cells (HSCs) transplantation was introduced as curative treatment for various diseases. Cryopreservation of HSCs is crucial for long term storage and maintenance of cellular quality; however, it has been reported that cryopreservation itself causes oxidative stress-driven apoptosis and cell loss. This study investigated impact of supplementing N-acetylcysteine (NAC) as antioxidant during cryopreservation on viability and oxidative stress in HSCs. HSCs were isolated from murine bone marrow, cultured in HSCs growth media and cryopreserved (1×106 cells per vial) together with 10% DMSO and NAC (0, 0.25, 0.5 or 2.0 μM) for 48 h, 2 weeks or 8 weeks at -196°C using controlled-rate-freezing technique. Cell viability and oxidative stress in cryopreserved cells were analysed at each time-point. Cell viability was significantly reduced (p<0.05) following cryopreservation as compared to pre-cryopreservation. NAC supplementation significantly increased cell viability (p<0.05) after 48 h cryopreservation at 0.5 μM and 2.0 μM and after 2 weeks cryopreservation at 0.25 μM compared to the controls. Cryopreservation significantly enhanced GSH level (p<0.05) and reduced MDA level (p<0.05) without affecting SOD activity and PC level in HSCs compared to pre-cryopreservation. NAC supplementation significantly increased GSH level at 0.25 μM in cryopreserved HSCs compared to control. In conclusion, NAC supplementation during cryopreservation showed potential in minimizing cryoinjury by promoting cell viability, increasing antioxidant capacity and reducing oxidative damage in HSCs, however these effects are influenced by both durations of cryopreservation and NAC concentration

Clastogenicity and Aneugenicity of 1,4-Benzoquinone in Different Lineages of Mouse Hematopoietic Stem/Progenitor Cells

Previous reports on hematotoxicity and leukemogenicity related to benzene exposure highlighted its adverse effects on hematopoiesis. Despite the reported findings, studies concerning the mechanism of benzene affecting chromosomal integrity in lineage-committed hematopoietic stem/progenitor cells (HSPCs) remain unclear. Here, we studied the clastogenicity and aneugenicity of benzene in lineage-committed HSPCs via karyotyping. Isolated mouse bone marrow cells (MBMCs) were exposed to the benzene metabolite 1,4-benzoquinone (1,4-BQ) at 1.25, 2.5, 5, 7, and 12 μM for 24 h, followed by karyotyping. Then, the chromosomal aberration (CA) in 1,4-BQ-exposed hematopoietic progenitor cells (HPCs) comprising myeloid, Pre-B lymphoid, and erythroid lineages were evaluated following colony-forming cell (CFC) assay. Percentage of CA, predominantly via Robertsonian translocation (Rb), was increased significantly (p &lt; 0.05) in MBMCs and all progenitors at all concentrations. As a comparison, Pre-B lymphoid progenitor demonstrated a significantly higher percentage of CA (p &lt; 0.05) than erythroid progenitor at 1.25, 2.5, and 7 μM as well as a significantly higher percentage (p &lt; 0.05) than myeloid progenitor at 7 μM of 1,4-BQ. In conclusion, 1,4-BQ induced CA, particularly via Rb in both MBMCs and HPCs, notably via a lineage-dependent response. The role of lineage specificity in governing the clastogenicity and aneugenicity of 1,4-BQ deserves further investigation