Evaluation of hematopoietic stem cell expansion in the presence of garcinol.

OBJECTIVE: The application of human cord blood (hCB) is limited to children by using relatively small volume of cord blood that does not contain enough hematopoietic stem cells (HSCs). So, efforts for applying cord blood stem cells in transplantation have led to establishment of some approaches for ex vivo expansion of HSCs such as garcinol. MATERIALS AND METHODS: CD133+ HSCs were separated by a magnetic-activated cell sorting (MACS) system. Isolated cells were cultured with different doses of garcinol, SCF, TPO and FLT-3L. The optimal dose of garcinol for ex vivo expansion of HSCs was determined by direct counting. Flow cytometry was used to evaluate the expression of CD133 marker to check the ability of garcinol in maintenance of HSCs. Colony forming cell (CFC) assay was performed to evaluate clonogenic capability of treated cells. The level of expression of CXCR4 gene was evaluated by RT-PCR. Data were analyzed using Student's t test. RESULTS: Our results showed that CD133+ HSCs in the presence of garcinol (5-10 µM) had high expansion activity and cell counting showed that the number of cells in treated group was higher than control group (1.9 -fold) and CFC assay showed that the number of colonies following treatment with garcinol had 1.3-fold increase. Treatment of HSCs with garcinol resulted in 9.6-fold increase in terms of CXCR4 expression in comparison to control group. CONCLUSION: The present study showed that garcinol can improve ex vivo expansion of HSCs and enhance their potential for homing to bone marrow.

Erythropoietin induces production of hepatocyte growth factor from bone marrow mesenchymal stem cells in vitro.

BACKGROUND: Hepatocyte Growth Factor (HGF) plays a pivotal role in hematopoiesis, motility, growth and mobilization of hematopoietic stem/progenitor cells (HSPCs). HGF mainly is produced by bone marrow mesenchymal stem cells (BM-MSCs). MSCs express erythropoietin (EPO) receptor. In this study, we aimed to assess the effect of EPO on HGF secretion in BM-MSCs. METHODS: The BM-MSCs treated with EPO (4 IU/ml) for 6, 24 and 48 h. HGF gene expression and protein level were assessed using quantitative real time PCR (qRT-PCR) and Enzyme-linked immunosorbant Assay. In order to show the effect of secreted HGF on migration of HSPCs, hematopoietic stem cells (HSCs) were isolated from cord blood and evaluated using transwell migration assay. RESULTS: We observed a significant increase in level of HGF in cell supernatant after 48 h compared to control group (P < 0.05). Also, qRT-PCR results demonstrated a significant elevation in HGF expression level after 24 and 48 h treatment with EPO compared to control group (P < 0.05). Finally, migration assay results showed a significant increase in migration of HSCs in treated group after 48 h. CONCLUSION: Our data indicated that EPO may play an important role in stem cell mobilization through up regulating HGF in MSCs and inducing migration of HSCs.

Possible involvement of miRNAs in tropism of Parvovirus B19.

Human Parvovirus B19 (PVB19) is one of the most important pathogens that targets erythroid lineage. Many factors were mentioned for restriction to erythroid progenitor cells (EPCs). Previous studies showed that in non-permissive cells VP1 and VP2 (structural proteins) mRNAs were detected but could not translate to proteins. A bioinformatics study showed that this inhibition might be due to specific microRNAs (miRNAs) present in non-permissive cells but not in permissive EPCs. To confirm the hypothesis, we evaluated the effect of miRNAs on VP expression. CD34(+) HSCs were separated from cord blood. Then, CD34(+) cells were treated with differentiation medium to obtain CD36(+) EPCs. To evaluate the effect of miRNAs on VP expression in MCF7 and HEK-293 cell lines (non-permissive cells) and CD36(+) EPCs, dual luciferase assay was performed in presence of shRNAs against Dicer and Drosha to disrupt miRNA biogenesis. QRT-PCR was performed to check down-regulation of Dicer and Drosha after transfection. All measurements were done in triplicate. Data means were compared using one-way ANOVAs. MicroRNA prediction was done by the online microRNA prediction tools. No significant difference was shown in luciferase activity of CD36(+) EPCs after co-transfection with shRNAs, while it was significant in non-permissive cells. Our study revealed that miRNAs may be involved in inhibition of VP expression in non-permissive cells, although further studies are required to demonstrate which miRNAs exactly are involved in regulation of PVB19 replication.

Differential characteristics of CD133(+) and CD133 (-) Jurkat cells.

T cell acute lymphoblastic leukemia (T-ALL) is a hematological disease including malignancy of T cell precursors. There are some T-ALL patients that are drug-resistant. A major cause of treatment failure in cancers can be associated with the existence of cancer stem cells. The identification of these cell populations helps us to clarify resistance mechanisms and rely on special markers for recognizing cancer stem cells. CD133 is one of the markers that is used for the identification of cancer stem cells. In this study, we evaluated CD133(+) and CD133(-) characteristic cells in Jurkat cells by assay proliferation, invasion, and apoptosis. CD133(+) and CD133(-) Jurkat cells were separated and immediately analyzed for proliferation, invasion, and doxorubicin-induced apoptosis. Proliferation, invasion, and resistance to chemotherapy of CD133(+) Jurkat cells were significantly more than CD133(-) Jurkat cells. Also, our results showed that CD133(+) Jurkat cells expressed ABCG2 gene more than CD133(-) Jurkat cells. In conclusion, CD133 marker could be introduced as a specific marker of cancer stem cells in Jurkat cell line.