Endothelial progenitor cells improve the quality of transplanted hematopoietic stem cells and maintain longer term effects in mice.

Engraftment of hematopoietic stem cells (HSCs) is a pre-requisite for the success of hematopoietic stem cell transplantation (HSCT). Fetal blood cell (FBC)-derived endothelial progenitor cells (EPCs) are known to facilitate HSC reconstitution in the early phase. However, longer term effects on HSCs remain unclear. The purpose of this study was to evaluate the effect of EPCs on the quality of transplanted hematopoietic stem cells in mouse HSCT model. BALB/c mice were randomly divided into four groups, namely, control, total body irradiation only, HSCT, and HSCT + EPCs (with infusion of 5 × 105 EPCs). Mice was sacrificed on days 7, 14, 21, and 28 post-HSCT for the analysis of the bone marrow pathology by H&E staining, measurement of c-kit+sca-1+, c-kit+, apoptosis, and necrosis by flow cytometry as well as colony formation assay. Secondary transplantation involved the injection of transplanted BALB/c-derived HSCs into new TBI-treated BALB/c mice. Compared with HSCT, EPCs infusion promoted the differentiation and reduced apoptosis of transplanted HSCs, possibly through promotion of vascular repair of the bone marrow microenvironment via differentiation into the bone marrow endothelial cells. Significantly, EPCs' effect on HSCs was maintained for a long period as demonstrated using a secondary transplantation approach. These data revealed EPCs improved the quality and quantity of transplanted HSCs and maintained their effects over the longer term, suggesting a novel approach to improve HSCT efficiency and outcomes.

Blockage of caspase-1 activation ameliorates bone marrow inflammation in mice after hematopoietic stem cell transplantation.

Conditioning regimens before hematopoietic stem cell transplantation (HSCT), cause damage to bone marrow and inflammation. Whether inflammasomes are involved in bone marrow inflammation remains unclear. The study aims to evaluate the role of inflammasomes in bone marrow inflammation after HSCT. On days 7, 14, 21 and 28 after HSCT, mice were sacrificed for analysis of bone marrow inflammation, pro-inflammatory cytokines secretion, inflammasomes expression and caspase-1 activation. Bone marrow inflammation with neutrophils and macrophages infiltration was observed after HSCT. Secretion of IL-1ß, IL-18, TNF-α and IL-6 were elevated, with increased caspase-1 activation and inflammasomes expression. Caspase-1 inhibitor administration after HSCT significantly reduced infiltration of neutrophils and macrophages into bone marrow and increased the numbers of megakaryocytes and platelets. In conclusion, inflammasomes activation is involved in bone marrow inflammation after HSCT and caspase-1 inhibition attenuates bone marrow inflammation and promoted hematopoietic reconstitution, suggesting targeting caspase-1 might be beneficial for improving HSCT outcomes.

Long non-coding RNAs expression profiles in hepatocytes of mice after hematopoietic stem cell transplantation.

Hepatic veno-occlusive disease (HVOD), one serious complication following hematopoietic stem cell transplantation (HSCT), is mainly initiated by the damage to sinusoidal endothelial cells and hepatocytes. Long non-coding RNAs (lncRNAs) play an important role in the proliferation of hepatocytes and liver regeneration. lncRNAs profile in hepatocytes post-HSCT remains unclear. The aim of this study is to evaluate the profile of lncRNAs in hepatocytes of mice after HSCT. Mice HSCT model was established through infusion of 5 × 10(6) bone marrow mononuclear cells. On day 7, 14 and 33 after HSCT, mice were sacrificed for analysis of liver pathology, function and index. Total RNA was extracted from hepatocytes of mice on day 14 for microarray analysis of the expression profiles of lncRNAs by Arraystar Mouse lncRNA Microarray v2.0. Obvious edema and spotty necrosis of hepatocytes with inflammatory cells infiltration were observed post-HSCT. Meanwhile, increased levels of alkaline phosphatase, aspartate transaminase, and total bilirubin, as well as elevated liver index were also found. 2,918 up-regulated and 1,911 down-regulated lncRNAs in hepatocytes were identified. Some of differentially expressed mRNAs had adjacent lncRNAs that were also significantly dysregulated, with the same dysregulation direction. T-cell receptor (up-regulation) and VEGF signaling pathway (down-regulation) were identified as one of the most enriched pathways. Dysregulated lncRNAs might be involved in hepatocytes damage after HSCT, suggesting targeting them might be a novel approach in amelioration of hepatocytes damage.

Infusion of endothelial progenitor cells ameliorates liver injury in mice after haematopoietic stem cell transplantation.

BACKGROUND & AIMS: Injury to liver sinusoidal endothelial cells (LSECs) is thought to be the initial factor for Hepatic veno-occlusive disease, a severe complication after haematopoietic stem cell transplantation (HSCT). Endothelial progenitor cells (EPCs) have the capacity to differentiate into endothelial cells and play a critical role in vasculogenesis, tissue regeneration and repair. Whether EPCs infusion ameliorates LSECs injury remains unclear. The aim of this study was to evaluate the effects of EPCs on liver injury in mice after HSCT. METHODS: Mice received HSCT without or with EPCs infusion (HSCT + EPCs). Untreated mice were used as control. Liver and whole blood were collected post HSCT and used for the analysis of pathology of liver sinusoidal endothelial cells (LSECs) and hepatocytes, liver ultrastructure, function, level of IL-6, TNF-α and platelet activation. RESULTS: Severe LSECs injury, hepatocyte damage, abnormal liver function was observed in HSCT group. In addition, increased P-selectin expression and secretion of IL-6, TNF-α was also found. However, all the above changes were alleviated in HSCT + EPCs at all the time points and normalized at the endpoint. Meanwhile, EPCs-induced repair of LSECs and hepatocytes was totally inhibited by the addition of anti-VE-cadherin antibody. CONCLUSIONS: EPCs infusion ameliorated the damage to LSECs and hepatocytes as well as reduced secretion of IL-6, TNF-α and inhibited platelet activation after HSCT, leading to improved liver function, suggesting EPCs might be a new therapeutic strategy in the prophylaxis of liver injury after HSCT.

Busulfan and cyclosphamide induce liver inflammation through NLRP3 activation in mice after hematopoietic stem cell transplantation.

The aim of this study was to evaluate the role of NLRP3 inflammasome on BU/CY-induced liver inflammation in mice after HSCT. HSCT mice model was established through infusion of 5 × 10(6) bone marrow mononuclear cells after conditioned with BU/CY. On day 7, 14, 21 and 28 after HSCT, mice were sacrificed for analysis of liver inflammation, cytokine secretion, NLRP3 expression and caspase-1 activation as well as release of ATP and high-mobility group protein B1 (HMGB1). Furthermore, NLRP3 selective inhibitor (BAY 11-7082) was administrated into mice after HSCT to evaluate its effects on liver inflammation. Severe liver inflammation and damage with elevated secretion of IL-1ß and IL-18 were found in mice after HSCT. Meanwhile, elevated expressions of NLRP3 and caspase-1 activation in liver were found. In addition, increased release of ATP and HMGB1 were observed. Selective inhibition of NLRP3 decreased caspase-1 activation and secretion of IL-1ß and IL-18. Furthermore, NLRP3 inhibition also reduced infiltration of macrophages and neutrophils and improved liver function. In conclusion, NLRP3 was involved in BU/CY-induced liver inflammation after HSCT and selectively inhibited it ameliorated liver inflammation and improved liver function, suggesting targeting NLRP3 might be a new approach in the prophylaxis of liver inflammation after HSCT.

Aberrant expression of RUNX3 in patients with immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disease, characterized by dysregulation of cellular immunity. Previous studies demonstrated that immune imbalance between Th1 and Th2 was associated with the pathogenesis of ITP. Runt-related transcription factor 3 (RUNX3) is a member of the runt domain-containing family of transcription factors and plays an important role in the regulation of T cell differentiation into Th1 cells. Whether RUNX3 was involved in the pathogenesis of ITP remains unclear. In this study, 47 active ITP patients, 18 ITP with remission and 26 age and gender matched healthy control were included. Peripheral blood mononuclear cells (PBMCs) were isolated from ITP and control for isolation of RNA and plasma which were used to measure mRNA level of RUNX3 and T-box transcription factor (T-bet) by quantitative real-time PCR and interferon γ (IFN-γ) plasma level by ELISA. Meanwhile, protein was also extracted from PBMCs for Western blot analysis of RUNX3 expression. Our results showed a significantly higher expression of RUNX3, T-bet and plasma level of IFN-γ in active ITP patients compared to control. No differences were observed between ITP with remission and control. Furthermore, a positive correlation of RUNX3 with T-bet was found in active ITP patients. In conclusion, aberrant expression of RUNX3 was associated with the pathogenesis of ITP and therapeutically targeting it might be a novel approach in ITP treatment.