Daoxin Ma

Elevated Th22 cells correlated with Th17 cells in patients with rheumatoid arthritis.

BackgroundT-helper (Th) 22 and Th17 cells are implicated in the pathogenesis of autoimmune diseases. The roles of Th22 cells in the pathophysiology of rheumatoid arthritis (RA) remain unsettled.Materials and MethodsCD4+IFNγ−IL17−IL-22+ T cells (Th22 cells), CD4+IFNγ−IL-22−IL17+ T cells (pure Th17 cells), CD4+IL17+ T cells (Th17 cells), and CD4+IFNγ+ T cells (Th1 cells) in RA, osteoarthritis patients, and healthy controls were examined by flow cytometry. Plasma IL-22 and IL-17 levels were examined by enzyme-linked immunosorbent assay.ResultsTh22 cells, pure Th17 cells, Th17 cells, and interleukin-22 were significantly elevated in RA patients compared with osteoarthritis and healthy controls, but there were no significant differences regarding Th1 cells and interleukin-17. Th22 cells showed a positive correlation with interleukin-22 as well as pure Th17 cells or Th17 cells in RA patients. Additionally, the percentages of Th22 cells, pure Th17 cells as well as Th17 cells correlated positively with both C-reactive protein levels and 28-joints disease activity score.ConclusionTogether, our results indicated a possible role of Th22 pure Th17 cells and Th17 cells in RA, and blockade of the interleukin-22 may be a reasonable therapeutic strategy for RA.

Curcumin inhibits proliferation and invasion of osteosarcoma cells through inactivation of Notch‐1 signaling

The Notch signaling pathway plays critical roles in human cancers, including osteosarcoma, suggesting that the discovery of specific agents targeting Notch would be extremely valuable for osteosarcoma. Curcumin, a naturally occurring phenolic compound found in curcuma longa, has been shown to inhibit proliferation and induce apoptosis of osteosarcoma cells in vitro and tumor growth in xenotransplant or orthotransplant models. However, the precise molecular mechanisms by which curcumin exerts its antitumor activity remain unclear. Here we used multiple molecular approaches, such as the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, the invasion assay, gene transfection, real‐time RT‐PCR, western blot and gelatin zymography, to investigate whether the downregulation of Notch‐1 contributes to curcumin‐induced inhibition of proliferation and invasion in osteosarcoma cells. The results showed that curcumin caused marked inhibition of osteosarcoma cell growth and G2/M phase cell cycle arrest. This was associated with concomitant attenuation of Notch‐1 and downregulation of its downstream genes, such as matrix metalloproteinases, resulting in the inhibition of osteosarcoma cell invasion through Matrigel. We also found that specific downregulation of Notch‐1 via small‐interfering RNA prior to curcumin treatment resulted in enhanced inhibition of cell growth and invasion. These results suggest that antitumor activity of curcumin is mediated through a novel mechanism involving inactivation of the Notch‐1 signaling pathway. Our data provide the first evidence that the downregulation of Notch‐1 by curcumin may be an effective approach for the treatment of osteosarcoma.

Notch1 is required for hypoxia-induced proliferation, invasion and chemoresistance of T-cell acute lymphoblastic leukemia cells.

BackgroundNotch1 is a potent regulator known to play an oncogenic role in many malignancies including T-cell acute lymphoblastic leukemia (T-ALL). Tumor hypoxia and increased hypoxia-inducible factor-1α (HIF-1α) activity can act as major stimuli for tumor aggressiveness and progression. Although hypoxia-mediated activation of the Notch1 pathway plays an important role in tumor cell survival and invasiveness, the interaction between HIF-1α and Notch1 has not yet been identified in T-ALL. This study was designed to investigate whether hypoxia activates Notch1 signalling through HIF-1α stabilization and to determine the contribution of hypoxia and HIF-1α to proliferation, invasion and chemoresistance in T-ALL.MethodsT-ALL cell lines (Jurkat, Sup-T1) transfected with HIF-1α or Notch1 small interference RNA (siRNA) were incubated in normoxic or hypoxic conditions. Their potential for proliferation and invasion was measured by WST-8 and transwell assays. Flow cytometry was used to detect apoptosis and assess cell cycle regulation. Expression and regulation of components of the HIF-1α and Notch1 pathways and of genes related to proliferation, invasion and apoptosis were assessed by quantitative real-time PCR or Western blot.ResultsHypoxia potentiated Notch1 signalling via stabilization and activation of the transcription factor HIF-1α. Hypoxia/HIF-1α-activated Notch1 signalling altered expression of cell cycle regulatory proteins and accelerated cell proliferation. Hypoxia-induced Notch1 activation increased the expression of matrix metalloproteinase-2 (MMP2) and MMP9, which increased invasiveness. Of greater clinical significance, knockdown of Notch1 prevented the protective effect of hypoxia/HIF-1α against dexamethasone-induced apoptosis. This sensitization correlated with losing the effect of hypoxia/HIF-1α on Bcl-2 and Bcl-xL expression.ConclusionsNotch1 signalling is required for hypoxia/HIF-1α-induced proliferation, invasion and chemoresistance in T-ALL. Pharmacological inhibitors of HIF-1α or Notch1 signalling may be attractive interventions for T-ALL treatment.

Increased Number of Tc17 and Correlation with Th17 Cells in Patients with Immune Thrombocytopenia

Background IL-17-secreting CD8+ T cells (Tc17 subset) have recently been defined as a subpopulation of effector T cells implicated in the pathogenesis of autoimmune diseases. The role of Tc17 and correlation with Th17 cells in the pathophysiology of immune thrombocytopenia (ITP) remain unsettled. Design and Methods We studied 47 ITP patients (20 newly-diagnosed and 27 with complete response) and 34 healthy controls. IL-17-producing CD3+CD8+ cells (Tc17) and IL-17-producing CD3+CD8− cells (Th17) were evaluated by flow cytometry and expressed as a percentage of the total number of CD3+ cells. Specific anti-platelet glycoprotein (GP) GPIIb/IIIa and/or GPIb/IX autoantibodies were measured by modified monoclonal antibody specific immobilization of platelet antigens. Peripheral blood mononuclear cells of ITP patients were isolated, incubated in the presence of 0, 0.25, 0.5, or 1 µmol/L of dexamethasone for 72 h, and collected to detect Tc17 and Th17 cells by flow cytometric analysis. Results IL-17 was expressed on CD3+CD8− and CD3+CD8+ T cells. The percentages of Tc17 and Th17 cells in newly-diagnosed patients were significantly elevated compared to controls, and Tc17 was decreased after clinical treatment. The Th17∶Tc17 ratio was significantly lower in newly-diagnosed patients compared with controls, and was increased in patients who had complete response. There was a significantly positive correlation between Tc17 and Th17 cells in the control group, but not in the ITP patients. A positive correlation existed between Tc17 and the CD8∶CD4 ratio, as well as CD8+ cells in patients with ITP. The frequencies of Tc17 were marginally higher in autoantibody-negative patients than autoantibody-positive patients. Moreover, both Tc17 and Th17 cell percentages decreased as the concentration of dexamethasone in the culture media increased in ITP patients. Conclusions Tc17 and the Th17 subset are involved in the immunopathology of ITP. Blocking the abnormally increased number of Tc17 may be a reasonable therapeutic strategy for ITP.

Elevated profiles of Th22 cells and correlations with Th17 cells in patients with immune thrombocytopenia

T-helper (Th) 22 and Th17 cells are implicated in the pathogenesis of autoimmune diseases. However, the role of Th22 cells in the pathophysiology of immune thrombocytopenia (ITP) remains unclear. Th22, Th17 and Th1 cells in both ITP patients and healthy controls were examined by flow cytometry. Plasma interleukin-22 (IL-22) level was measured by enzyme linked immunosorbent assay (ELISA). Signal transducers and activators of transcription 3 (STAT-3) and transcription factor RAR-related organ receptor C (RORC) messenger RNA (mRNA) expressions were examined by quantitative reverse transcription polymerase chain reaction (RT-PCR). Th22 cells, Th17 cells, Th1 cells and plasma IL-22 were significantly higher in ITP patients than in healthy controls. Moreover, Th22 cells showed a positive correlation with the levels of plasma IL-22 as well as Th17 and Th1 cells in ITP patients. Significant up-regulations of both STAT-3 and RORC transcription factors were also observed. Additionally, the percentage of Th22 cells was higher in autoantibody-negative ITP patients than in autoantibody-positive patients. Our results demonstrate a possible role of Th22 cells in ITP, and thus, the blockade of IL-22 may be a reasonable therapeutic strategy for ITP.

Th22 and related cytokines in inflammatory and autoimmune diseases

Introduction: Th22 and related cytokines regulate various processes and have been linked to diverse effects. The levels of Th22 and cytokine IL-22 are increased in several disorders and positively related to some autoimmune diseases. Preclinical studies have suggested that the inhibition or stimulation of IL-22 is an attractive approach to reverse the immune disorders. Simultaneously, considering many patients with refractory autoimmune diseases respond poorly to the therapies which are highly toxic, more effective therapies are to be examined. Areas covered: The role of Th22 cells and related cytokines and therapeutic strategies targeting them in many illnesses, especially inflammatory and autoimmune diseases. Expert opinion: Th22 cells and related cytokine IL-22 regulate multiple biological functions and play an important role in a number of inflammatory and autoimmune diseases. They have unique and attractive advantages for targeting. Targeting IL-22 has already been trialed in many mice experiments, showing better efficacy and fewer side effects compared with classical drugs. Targeting IL-22 or Th22 might provide pathogenetic treatment. However, Th22 subset is a recently identified Th subset and its associated research is extremely limited. Therefore, there are still many unanswered questions and further researches are warranted.

Cross-talk between leukemic and endothelial cells promotes angiogenesis by VEGF activation of the Notch/Dll4 pathway

Angiogenesis is suggested to be important for leukemogenesis and chemosensitivity in acute myeloid leukemia (AML). The vascular endothelial growth factor (VEGF) and Notch/Dll4 pathways have been identified as critical in the regulation of embryonic vascular development and tumor angiogenesis. However, the potential role of the Notch/Dll4 pathway in leukemia-endothelium cross-talk and its functional link with VEGF remains obscure. This study assessed the expression of VEGF and Notch/Dll4 pathway molecules in primary AML and investigated their biological function in the coculture of endothelial cells with AML cells. The results demonstrated that bone marrow vascularity in the newly diagnosed AML patients was increased and correlated with high VEGF and Dll4 expression. Patients with untreated AML expressed higher levels of VEGFR2, Notch1, Dll4 and Hes1 than healthy controls. Moreover, the activation of the Notch/Dll4 pathway is associated with poor prognosis in AML. In addition, AML cells were shown to increase endothelial cell proliferation in Transwell coculture. This was associated with concomitant activation of the Notch/Dll4 pathway and upregulation of its downstream genes, such as matrix metalloproteinases, resulting in the enhancement of endothelial cell migration and tube formation. Our study also showed that upregulation of Dll4 expression in AML cells by cDNA transfection suppressed VEGF-induced endothelial cell proliferation and angiogenesis in direct contact coculture. These results elucidate a novel mechanism by which the interplay between AML and endothelial cells promotes angiogenesis through the Notch/Dll4 pathway. Modulation of this pathway may, therefore, hold promise as a novel antiangiogenic strategy for the treatment of AML.

Th22 Cells as Well as Th17 Cells Expand Differentially in Patients with Early-Stage and Late-Stage Myelodysplastic Syndrome

Background Immunological mechanisms are increasingly recognized in the progression of myelodysplastic syndrome (MDS). Early-stage MDS (E-MDS) is characterized by autoimmune-mediated myelosuppression whereas late-stage MDS (L-MDS) involves immune evasion, giving dysplastic cells growth potential to progress into acute myeloid leukemia. T-helper (Th) 22 is involved in the pathogenesis of inflammatory autoimmunity and tumorigenesis. The roles of Th22 cells in the pathophysiology of E-MDS and L-MDS remain unsettled. Design and Methods We studied 37 MDS patients (E-MDS, n = 17; L-MDS, n = 20) and 20 healthy controls to characterize their peripheral blood (PB), as well as 25 MDS patients and 10 healthy controls to characterize their bone marrow(BM). The expression of Interleukin-22 (IL-22), IL-17 or interferon gamma (IFN-γ) was examined in E-MDS, L-MDS patients and controls by flow cytometry. The mRNA expression levels of RAR-related orphan receptor C (RORC), IL-6, tumor necrosis factor alpha (TNF-α) and IL-23 in peripheral blood mononuclear cells (PBMCs) were determined by real-time quantitative polymerase chain reaction. The levels of IL-22 and IL-17 both in PB and BM plasma were examined by enzyme-linked immunosorbent assay. Results In E-MDS, peripheral Th17 cells were significantly elevated and correlated with peripheral Th22 cells compared with healthy controls and L-MDS. Significantly higher levels of peripheral Th22 expansion, mRNA expression of IL-6, TNF-α and lower level of RORC mRNA expression were observed in L-MDS compared with E-MDS. No statistical difference was found in IL-23 mRNA expression or plasma IL-22, IL-17 levels among E-MDS, L-MDS and controls. Conclusions Our data demonstrated that L-MDS cohort had increased frequencies of peripheral Th22 cells and higher mRNA expression levels of IL-6 and TNF-α, indicating that Th22 cells along with Th17 cells or not are involved in the dynamic immune responses of MDS.

Characterization of hsa_circ_0004277 as a New Biomarker for Acute Myeloid Leukemia via Circular RNA Profile and Bioinformatics Analysis

Circular RNAs (circRNAs) represent a widespread class of non-coding RNAs, which drew little attention in the past. Recently, limited data showed their promising future to act as biomarkers in human cancer, but the characteristics and functions remain largely unknown in hematopoietic malignancies, especially in leukemia. In this study, with the help of circRNA microarray, we demonstrated the expression profile of circRNAs in acute myeloid leukemia (AML) patients, and identified a large number of circRNAs possibly expressed in a leukemia specific manner. We also described a circRNA signature related to AML risk-status based on the bioinformatics prediction. In particular, a downregulated circRNA, hsa_circ_0004277, was characterized and functionally evaluated in a cohort of 115 human samples, thus offering a potential diagnostic marker and treatment target in AML. Interestingly, we found chemotherapy could significantly restore the expression of hsa_circ_0004277, indicating the increasing level of hsa_circ_0004277 was associated with successful treatment. Furthermore, a detailed circRNA–miRNA–mRNA interaction network was presented for hsa_circ_0004277, allowing us to better understand its underlying mechanisms for function in AML.

Syntaxin‐11 is expressed in primary human monocytes/macrophages and acts as a negative regulator of macrophage engulfment of apoptotic cells and IgG‐opsonized target cells

Syntaxin‐11 is a member of a family of membrane‐trafficking proteins referred to as soluble N‐ethylmaleimide‐sensitive factor attachment protein receptors (SNAREs). Recent studies have shown that syntaxin‐11 is expressed in natural killer cells and cytotoxic T cells and is likely to play a role in the granule exocytosis pathway. However, the biological role of syntaxin‐11 in other immune cells has remained elusive. This study found that stimulation with interferon‐γ upregulated syntaxin‐11 expression in primary monocytes. Experiments using monocytes from patients with familial haemophagocytic lymphohistiocytosis harbouring mutations in the gene encoding syntaxin‐11 (STX11), or monocytes from healthy individuals in which syntaxin‐11 was downregulated using specific short‐interfering RNA, demonstrated that syntaxin‐11 was not required for antibody‐dependent cellular cytotoxicity. On the other hand, silencing of syntaxin‐11 expression in primary macrophages enhanced the phagocytosis of apoptotic target cells with a concomitant increase in macrophage secretion of tumour necrosis factor‐α. Moreover, Fcγ‐receptor‐mediated uptake of target cells was also enhanced following silencing of syntaxin‐11 expression in macrophages. In addition, syntaxin‐11 localized to the plasma membrane in macrophages ingesting apoptotic cell corpses. Syntaxin‐11 thus appears to act as a negative regulator of human macrophage engulfment of apoptotic cells and IgG‐opsonized red blood cells.