Development of B cells and erythrocytes is specifically impaired by the drug celastrol in mice

Abstract

Background: Celastrol, an active compound extracted from the root of the Chinese medicine "Thunder of God Vine" (Tripterygium wilfordii), exhibits anticancer, antioxidant and anti-inflammatory activities, and interest in the therapeutic potential of celastrol is increasing. However, described side effects following treatment are significant and require investigation prior to initiating clinical trials. Here, we investigated the effects of celastrol on the adult murine hematopoietic system.

Methodology/principal findings: Animals were treated daily with celastrol over a four-day period and peripheral blood, bone marrow, spleen, and peritoneal cavity were harvested for cell phenotyping. Treated mice showed specific impairment of the development of B cells and erythrocytes in all tested organs. In bone marrow, these alterations were accompanied by decreases in populations of common lymphoid progenitors (CLP), common myeloid progenitors (CMP) and megakaryocyte-erythrocyte progenitors (MEP).

Conclusions/significance: These results indicate that celastrol acts through regulators of adult hematopoiesis and could be used as a modulator of the hematopoietic system. These observations provide valuable information for further assessment prior to clinical trials.

Conflict of interest statement

Competing Interests: CC is a founder of Xenogen Corp., now part of Caliper LifeSciences. This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials. All other authors have declared that no competing interests exist.

Figures

Figure 1. Changes in peripheral blood parameters and cellularity in celastrol treated-BALB/c mice.

(A) Peripheral blood parameters in celastrol treated-mice. Mice received four consecutive daily IP injections of DMSO 5% or various concentrations of celastrol (0.01, 0.1, 1 or 5 mg/kg/day). Peripheral blood was harvested the day following the last injection. Values are percent of control. RBC: red blood cells; HGB: Hemoglobin; HCT: hematocrit; WBC: white blood cells. Mean ± SEM, n = 10. (B) Cellularity in control and celastrol treated-mice. Mice received four consecutive daily IP injections of DMSO 5% or celastrol (5 mg/kg). Cells from bone marrow (1 femur+1 tibia), spleen and peritoneal cavity were harvested the day following the last injection. Mean ± SEM, n = 10.

Figure 2. Celastrol treatment results in multiple defects in mature lineages.

(A) Representative FACS analysis of mature lineages from peripheral blood of control (left) and celastrol treated-mice (right). Mice received four consecutive daily intraperitoneal injections and peripheral blood cells were harvested the day following the last injection, processed and analyzed as described in Materials and Methods. The percentages shown correspond to raw data numbers. Data shown are representative of 10 mice. (B) Representative FACS analysis of total B cells (gated as LIVE/DEAD+, CD5−, CD19+, and analyzed for IgD and IgM expression) from bone marrow, spleen and peritoneal cavity of control (left) and celastrol treated-mice (right) (n = 10). FACS-analysis of the different sub-populations of B lymphoid progenitors was performed as described , . MZ B cells: Marginal Zone B cells. (C) Representative FACS analysis of total red cells (gated as LIVE/DEAD+, CD5−, CD19−, CD11b−, Gr-1−, SSC-Alow and analyzed for CD71 and Ter119 expressions) from bone marrow, spleen and peritoneal cavity of control (left) and celastrol treated-mice (right) (n = 10). FACS-analysis of the different sub-populations of red cell progenitors was performed as described , .

Figure 3. Celastrol treatment results in multiple defects in BM progenitors.

Representative FACS analysis of Megakaryocyte-Erythrocyte Progenitors (MEP), Common Myeloid Progenitors (CMP), Granulocyte-Monocyte Progenitors (GMP), LSK CD34− (Lin− Sca-1+ c-Kit+ CD34−) cells and Common Lymphoid Progenitors (CLP) from bone marrow of control (left) and celastrol treated-mice (right) (n = 10). Cells were harvested from animals treated as described in Figure 2 and percentages shown correspond to raw data numbers. FACS-analysis of the different sub-populations of multipotent progenitors was performed as described .