Kangni Wu

Hypoxia-Inducible Factor-1α Is Essential for Hypoxia-Induced Mesenchymal Stem Cell Mobilization into the Peripheral Blood

Mobilization of mesenchymal stem cells (MSCs) is a promising strategy for tissue repair and regenerative medicine. The establishment of an appropriate animal model and clarification of the underlying mechanisms are beneficial to develop the mobilization regimens for therapeutic use. In this study, we therefore established a rat MSC mobilization model and investigated the related mechanisms, using continuous hypoxia as the mobilizing stimulus. We found that MSCs could be mobilized into peripheral blood of rats exposed to short-term hypoxia (2 days) and the mobilization efficiency increased in a time-dependent manner (2-14 days). Hypoxia-inducible factor-1α (HIF-1α) was upregulated during hypoxic exposure and was expressed continuously in bone marrow. Inhibition of HIF-1α expression by YC-1 remarkably reduced the number of mobilized MSCs, suggesting that HIF-1α is essential for hypoxia-induced MSC mobilization. Further, we investigated the potential role of HIF-1α target genes, vascular endothelial growth factor (VEGF), and stromal cell-derived factor-1α (SDF-1α). VEGF expression was elevated from day 2 to day 7 of hypoxia, stimulating an increase in bone marrow sinusoidal vessels and possibly facilitating the egress of MSCs. SDF-1α protein levels were increased in the peripheral blood of rats during MSC mobilization and promoted the migration of MSCs under hypoxic conditions in vitro. These results suggest that HIF-1α plays a pivotal role in hypoxia-induced MSC mobilization, possibly acting via its downstream genes VEGF and SDF-1α. These data provide a novel insight into the mechanisms responsible for MSC mobilization and may help in the development of clinically useful therapeutic agents.

Efficient Commitment to Functional CD34+ Progenitor Cells from Human Bone Marrow Mesenchymal Stem-Cell-Derived Induced Pluripotent Stem Cells

The efficient commitment of a specialized cell type from induced pluripotent stem cells (iPSCs) without contamination from unknown substances is crucial to their use in clinical applications. Here, we propose that CD34+ progenitor cells, which retain hematopoietic and endothelial cell potential, could be efficiently obtained from iPSCs derived from human bone marrow mesenchymal stem cells (hBMMSC-iPSCs) with defined factors. By treatment with a cocktail containing mesodermal, hematopoietic, and endothelial inducers (BMP4, SCF, and VEGF, respectively) for 5 days, hBMMSC-iPSCs expressed the mesodermal transcription factors Brachyury and GATA-2 at higher levels than untreated groups (P<0.05). After culturing with another hematopoietic and endothelial inducer cocktail, including SCF, Flt3L, VEGF and IL-3, for an additional 7–9 days, CD34+ progenitor cells, which were undetectable in the initial iPSC cultures, reached nearly 20% of the total culture. This was greater than the relative number of progenitor cells produced from human-skin-fibroblast-derived iPSCs (hFib-iPSCs) or from the spontaneous differentiation groups (P<0.05), as assessed by flow cytometry analysis. These induced cells expressed hematopoietic transcription factors TAL-1 and SCL. They developed into various hematopoietic colonies when exposed to semisolid media with hematopoietic cytokines such as EPO and G-CSF. Hematopoietic cell lineages were identified by phenotype analysis with Wright-Giemsa staining. The endothelial potential of the cells was also verified by the confirmation of the formation of vascular tube-like structures and the expression of endothelial-specific markers CD31 and VE-CADHERIN. Efficient induction of CD34+ progenitor cells, which retain hematopoietic and endothelial cell potential with defined factors, provides an opportunity to obtain patient-specific cells for iPSC therapy and a useful model for the study of the mechanisms of hematopoiesis and drug screening.

Decitabine facilitates the generation and immunosuppressive function of regulatory γδT cells derived from human peripheral blood mononuclear cells

Decitabine facilitates the generation and immunosuppressive function of regulatory γδT cells derived from human peripheral blood mononuclear cells

Relationship between TNFA, TNFB and TNFRII gene polymorphisms and outcome after unrelated hematopoietic cell transplantation in a Chinese population

This study aimed to analyze the association between cytokine gene polymorphisms and outcome following allogeneic hematopoietic SCT (allo-HSCT). A total of 138 unrelated donor/recipient pairs who underwent allo-HSCT from 2001 to 2009 were tested for TNFA-1031 (T>C), -863 (C>A), -857 (C>T), -238 (G>A), TNFB+252 (A>G) and TNFRII codon 196 (T>G) single nucleotide polymorphisms by multiplex SnaPshot analysis. Transplantation involving recipients and/or donors with TNFA-857 C/C genotype or TNFB+252 G allele-positivity resulted in a higher incidence of acute GVHD (aGVHD), which was independent of HLA mismatching. In multivariate analysis, TNFA-857 C/C genotype donors (relative risk (RR)=2.29, P=0.006) and TNFB+252 G allele-positive recipients (RR=1.789, P=0.036) were found to be significantly associated with an increased incidence of aGVHD. TNFA-857 C/C genotype donors (RR=3.748, P=0.002) and TNFB+252 G allele-positive recipients (RR=1.823, P=0.063) were also associated with the development of grades II–IV aGVHD. TNFRII polymorphism in recipients was also related to relapse rate, but no significant associations were found between TNFA, TNFB or TNFRII 196 genotype and cGVHD, relapse or overall survival after transplantation. These results provide the first report of an association between TNFA, TNFB and TNFRII polymorphic features and outcome of allo-HSCT in a Chinese population, and suggest an interaction between TNFA-857 and TNFB+252 genotypes and risk of aGVHD.

Long‐term outcomes of antithymocyte globulin in patients with hematological malignancies undergoing myeloablative allogeneic hematopoietic cell transplantation: a systematic review and meta‐analysis

Antithymocyte globulin (ATG) has shown efficacy in preventing acute GVHD (aGVHD) in allogeneic hematopoietic cell transplantation (allo‐HCT), but its efficacy in chronic GVHD (cGVHD) and long‐term outcomes remains controversial. We conducted a systematic review and meta‐analysis to evaluate potential benefit and risk of prophylactic ATG use in myeloablative HCT. We searched Pubmed, EMBASE, Cochrane databases, and included 10 trials (two RCTs and eight retrospective) comparing ATG use vs. control with a total of 1859 patients. The median follow‐ups were over two yr. Outcomes assessed included overall cGVHD, extensive cGVHD, overall survival (OS), disease‐free survival, relapse, and causes of death. Our results showed ATG significantly decreased overall cGVHD (RR = 0.59; 95% CI: 0.53–0.66, p < 0.00001), extensive cGVHD (RR = 0.34; 95% CI: 0.25–0.47, p < 0.00001). Pooled results also showed ATG use was associated with a marginal increased risk of relapse (RR = 1.28; 95% CI: 1.01–1.63, p = 0.04), and a non‐inferior OS (HR = 0.86; 95% CI: 0.74–1.01, p = 0.06). We conclude prophylactic use of ATG exerts a favorable effect in reducing cGVHD without survival impairment in a long term, although a higher relapse rate is a major threat.

Rapamycin interacts synergistically with idarubicin to induce T-leukemia cell apoptosis in vitro and in a mesenchymal stem cell simulated drug-resistant microenvironment via Akt/mammalian target of rapamycin and extracellular signal-related kinase signaling pathways.

Abstract T-cell acute lymphoblastic leukemias (T-ALLs) are clonal lymphoid malignancies with a poor prognosis, and still a lack of effective treatment. Here we examined the interactions between the mammalian target of rapamycin (mTOR) inhibitor rapamycin and idarubicin (IDA) in a series of human T-ALL cell lines Molt-4, Jurkat, CCRF-CEM and CEM/C1. Co-exposure of cells to rapamycin and IDA synergistically induced T-ALL cell growth inhibition and apoptosis mediated by caspase activation via the intrinsic mitochondrial pathway and extrinsic pathway. Combined treatment with rapamycin and IDA down-regulated Bcl-2 and Mcl-1, and inhibited the activation of phosphoinositide 3-kinase (PI3K)/mTOR and extracellular signal-related kinase (ERK). They also played synergistic pro-apoptotic roles in the drug-resistant microenvironment simulated by mesenchymal stem cells (MSCs) as a feeder layer. In addition, MSCs protected T-ALL cells from IDA cytotoxicity by up-regulating ERK phosphorylation, while rapamycin efficiently reversed this protective effect. Taken together, we confirm the synergistic antitumor effects of rapamycin and IDA, and provide an insight into the potential future clinical applications of combined rapamycin–IDA regimens for treating T-cell malignancies.

Inhibitory effects of imatinib mesylate on human epidermal melanocytes

In recent years, increasing attention has been focused on the skin hypopigmentation that develops after the initiation of imatinib mesylate therapy in patients with chronic myeloid leukaemia (CML).

Twin Pregnancy and Childbirth after Reduced-Intensity Conditioning Allogeneic Haematopoietic Stem Cell Transplantation Combined with Imatinib Mesylate for Chronic Myeloid Leukaemia: Case Report and Literature Review

The successful outcome of a pregnancy in a woman who had received reduced-intensity conditioning (RIC) allogeneic haematopoietic stem cell transplantation (allo-HSCT) for chronic myeloid leukaemia is reported; publications on recovery of ovarian function and pregnancy following myeloablative conditioning (MAC) or RIC allo-HSCT for haematological disorders are reviewed. Research suggests that RIC allo-HSCT may facilitate ovarian recovery. Indeed, in the case study presented, the patient had a successful twin pregnancy and delivery, subsequent to treatment. After a 5-year follow-up, the patient survives disease-free with a sustained molecular response; her children are both healthy, with no physical defects. These findings suggest that RIC allo-HSCT combined with short-term imatinib mesylate does not necessarily have profound effects on female fertility.

Dasatinib promotes the potential of proliferation and antitumor responses of human γδT cells in a long-term induction ex vivo environment.

Dasatinib promotes the potential of proliferation and antitumor responses of human γδT cells in a long-term induction ex vivo environment

γδ T cell and other immune cells crosstalk in cellular immunity.

γδ T cells have been recognized as effectors with immunomodulatory functions in cellular immunity. These abilities enable them to interact with other immune cells, thus having the potential for treatment of various immune-mediated diseases with adoptive cell therapy. So far, the interactions between γδ T cell and other immune cells have not been well defined. Here we will discuss the interactivities among them and the perspective on γδ T cells for their use in immunotherapy could be imagined. The understanding of the crosstalk among the immune cells in immunopathology might be beneficial for the clinical application of γδ T cell.