Dawei Guo

From autophagy to senescence and apoptosis in Angiotensin II-treated vascular endothelial cells.

The aim of this study was to explore if cell autophagy is activated by AngII before aging using human umbilical vascular endothelial cells (HUVECs). The ultrastructural analysis of HUVECs was performed to observe autophagosomes. The LC3‐II/LC3‐I ratio was determined by western blot assay. The β‐gal staining was used to identify cell senescence. The flow cytometry was performed to evaluate cell apoptosis. The BH3 domain analog ABT737 or Beclin‐1 knockdown by specific shRNA or valsartan was applied to investigate their effects on cell autophagy, senescence, and apoptosis induced by Ang II. Cell autophagy was initiated after Ang II treatment at 24 h. And cell senescence and apoptosis were observed in Ang II‐treated cells at 48 h. The significant interaction of Beclin‐1 and Bcl‐2 was detected at 48 h after Ang II treatment. Beclin‐1 was indispensable to Ang II‐induced autophagy, and its BH3 domain was required for the interaction with Bcl‐2 to attenuate autophagy. Pretreated with valsartan, cells were present with less autophagic, senescent, and apoptotic cells after Ang II stimulation. In conclusion, Ang II induced autophagy, senescence, and apoptosis of HUVECs progressively, and autophagy presented an early protective effect on vascular endothelial damage due to Ang II.

More expressions of BDNF and TrkB in multiple hepatocellular carcinoma and anti-BDNF or K252a induced apoptosis, supressed invasion of HepG2 and HCCLM3 cells

BackgroundBrain-derived neurotrophic factor (BDNF) and its receptor Tropomysin-related kinase B (TrkB) are commonly up-regulated in a variety of human tumors. However, the roles of BDNF/TrkB in hepatocellular carcinoma (HCC) have been poorly investigated.MethodsWe evaluated the expressions of BDNF and TrkB in 65 cases of HCC by immunohistochemical staining. Moreover, in human HCC cell lines of HepG2 and high metastatic HCCLM3, the secretory BDNF in supernatant was measured by ELISA, the effects of BDNF neutralizing antibody or Trk tyrosine kinase inhibitor K252a on apoptosis and invasion were examined by flow cytometry and transwell assay respectively.ResultsHigher expression of BDNF (63.1%) or positive expression of TrkB (55.4%) was found in HCC specimens, which was significantly correlated with multiple and advanced stage of HCC. BDNF secretory level in HCCLM3 was higher than that in HepG2 cells. Both anti-BDNF and K252a effectively induced apoptosis and suppressed invasion of HepG2 and HCCLM3 cells.ConclusionsThese findings suggested that BDNF/TrkB are essential for HCC cells survival and invasion. BDNF/TrkB signaling should probably be an effective target to prevent HCC advancement.

Cardiac allograft acceptance induced by blockade of CD40-CD40L costimulation is dependent on CD4+CD25+ regulatory T cells.

BACKGROUND We have demonstrated previously that CD4(+)CD25(+) regulatory T cells (Treg) are important for spontaneous hepatic allograft tolerance. In this study, we examine the role of Treg in cardiac allograft acceptance induced by blockade of the CD40-CD40L pathway. METHODS A heterotopic heart transplant model of major histocompatibility complex-mismatched mice was performed. Expression of forkhead/winged helix transcription factor (FoxP3) and/or the number of CD4(+)CD25(+) T cells in allografts and spleens were examined. The effect of Treg from the recipient or the donor on the induction and maintenance of long-term allograft survival was determined. Histologic analyses were also performed. The effects of Treg on CD4(+) and CD8(+) T cells were assessed. RESULTS The levels of FoxP3 and/or CD4(+)CD25(+) T cells increased in long-surviving allografts and spleens. Depletion of Treg in the recipients but not the donors before transplantation caused rejection. Histologic analyses of allografts with Treg depletion showed extensive leukocyte infiltration and tissue destruction. However, delayed depletion of Treg in long-surviving recipients did not shorten their survival. Treg depletion increased the function of CD4(+) and CD8(+) T cells. CONCLUSION Treg in the recipient but not in the donor is essential for long-term survival induced by CD40-CD40L blockade by inhibiting the function of CD4(+) and CD8(+) T cells; however, Treg are not important for maintenance. Both allograft and spleen are critical for induction of successful long-term survival.

Knockdown of BDNF suppressed invasion of HepG2 and HCCLM3 cells, a mechanism associated with inactivation of RhoA or Rac1 and actin skeleton disorganization.

Guo DW, Sun WY, Zhu L, Zhang H, Hou X, Liang J, Jiang X, Liu C. Knockdown of BDNF suppressed invasion of HepG2 and HCCLM3 cells, a mechanism associated with inactivation of RhoA or Rac1 and actin skeleton disorganization. APMIS 2012; 120: 469–76.

CD4+CD25+ regulatory T cells are not required for mesenchymal stem cell function in fully MHC-mismatched mouse cardiac transplantation

Although the immunomodulative properties of mesenchymal stem cells (MSCs) open up attractive possibilities in solid-organ transplantation, information concerning the optimal dose, route, timing of administration, major histocompatibility complex (MHC)-restriction and relevant mechanisms is currently lacking. Therefore, better characterization of MSC immunoregulatory activity and elucidation of its mechanisms are crucial. In this study, we confirmed that MSCs did not elicit proliferation by allogeneic CD4+ T cells, suggesting that MSCs were not immunogenic. By using C57BL/6 mouse MSCs as donor-derived or recipient-derived or as third-party MSCs, we discovered that MSCs suppressed CD4+ T cell proliferation and prolonged mouse cardiac allograft survival in a dose-dependent and non-MHC-restricted manner. We also found that intraperitoneal administration favored survival prolongation, although this prolongation was weaker than that via the intravenous route. Only infusion at earlier time points favored survival prolongation. Depletion of CD4+CD25+ T cells did not affect the immunosuppression of MSCs on CD4+ T cells. Moreover, MSCs did not induce regulatory T cells. The in vivo data revealed that MSCs did not increase the percentage of CD4+CD25+ T cells and FoxP3 expression. More importantly, we demonstrated for the first time that depletion of CD4+CD25+ T cells did not hinder MSC-induced survival prolongation, indicating that CD4+CD25+ regulatory T cells were not essential for the prolongation of MSC-mediated allograft survival.

Transplant long-surviving induced by CD40-CD40 ligand costimulation blockade is dependent on IFN-γ through its effect on CD4(+)CD25(+) regulatory T cells.

BACKGROUND IFN-γ was documented to be commonly associated with acute rejection. In the present study, we investigated the role of IFN-γ in the transplant long-surviving induced by blocking CD40-CD40 ligand (CD40-CD40L) costimulation and its mechanisms. METHODS IFN-γ expression in cardiac allografts and spleens from syngeneic and allogeneic recipients with or without anti-CD40L monoclonal antibody (MR-1) treatment was examined by real-time RT-PCR. The grafts survival time in Wild type (IFN-γ(+/+)) and IFN-γ deficient (IFN-γ(-/-)) recipients was investigated. Mixed lymphocyte reaction (MLR) of CD4(+) T cells and cytotoxic T lymphocyte (CTL) assay of CD8(+) T cells were also studied. FoxP3 expression in allografts and spleens from IFN-γ(+/+) or IFN-γ(-/-) recipients with MR-1 treatment was examined. Furthermore, FoxP3, IL-10 and CTLA-4 expressions and the suppressive capability of CD4(+)CD25(+) regulatory T cells were examined. RESULTS Rejected allografts showed significantly higher IFN-γ expression than long-surviving allografts. Allograft survival was not prolonged in nonimmunosuppressed IFN-γ(-/-) mice. Administration of MR-1 induced long-term survival in 90.1% of IFN-γ(+/+) recipients (98±6.6 days) but failed to do so in IFN-γ(-/-) group (16.2±4.0 days). IFN-γ(-/-) recipients facilitated the proliferation and CTL generation of T cells. The allografts and spleens from IFN-γ(+/+) recipients contained higher FoxP3 expression than IFN-γ(-/-) recipients. Moreover, CD4(+)CD25(+) T cells from IFN-γ(+/+) recipients displayed a higher FoxP3 and IL-10 expression and suppressive capability. CONCLUSION IFN-γ plays an important role in the long-surviving induced by blocking CD40-CD40L through inhibiting the function of activated T cells and increasing suppressive capability of CD4(+)CD25(+) regulatory T cells.

Expression of CXCR6 on CD8+ T cells was up-regulated in allograft rejection

CXCL16/SR-PSOX is a novel transmembrane-type chemokine, which was also identified as a novel scavenger receptor for oxidized low density lipoprotein. Its receptor CXCR6 expresses on activated CD8(+) T cells, type 1-polarized CD4(+), and constitutively expresses on NKT cells. Moreover, it has been shown that CXCL16 accumulated activated CD8(+) T cells to sites of inflammation. To date, the effect of CXCL16 (SR-PSOX)/CXCR6 on CD8(+) T cells and its role in allograft rejection/acceptance are not well understood. In the current study, we show that rejected allografts showed higher expressions of CXCR6 and CXCL16. More importantly, expression of CXCR6 on CD8(+) T cells was also up-regulated by rejection. However, the blockade of CXCL16(SR-PSOX)/CXCR6 interaction could not inhibit cytotoxic activity of CD8(+) T cells, and therefore, could not prolong the cardiac graft survival time.

D-dopachrome tautomerase is over-expressed in pancreatic ductal adenocarcinoma and acts cooperatively with macrophage migration inhibitory factor to promote cancer growth

Previous studies have established the important role of MIF in the development of pancreatic ductal adenocarcinoma (PDAC) for both therapeutic and diagnostic perspectives, but little is known about the expression and function of D‐dopachrome tautomerase (DDT), a functional homolog of MIF, in PDAC. In the present study, we demonstrated that DDT was over‐expressed in PDAC tissues in a pattern correlated with MIF. In the pancreatic cancer cell lines, PANC‐1, BXPC‐3 and ASPC‐1, both DDT and MIF were expressed and co‐localized with each other in the endosomal compartments and plasma membrane. Knockdown of DDT and MIF in PANC‐1 cells cooperatively inhibited ERK1/2 and AKT phosphorylation, increased p53 expression, and reduced cell proliferation, invasion and tumor formation. These effects were rescued by the re‐expression of MIF or DDT, but not by the forced expression of the tautomerase‐deficient mutants of DDT and MIF, P1G‐DDT and P1G‐MIF. Finally, we observed that 4‐iodo‐6‐phenylpyrimidine (4‐IPP), a covalent tautomerase inhibitor of both DDT and MIF, attenuated PANC‐1 cell proliferation and colony formation in vitro and tumor growth in vivo. Thus, targeting the tautomerase sites of both MIF and DDT may offer more efficient therapeutic benefits to PDAC patients.

De Garengeot hernia: the ultrasound and computed tomographic findings in an 81-year-old woman

The presence of appendix within a femoral hernia is a rare condition in an incarcerated femoral hernia. It has a characteristic groin mass, and the diagnosis of appendicitis is mainly made intraoperatively. A specific imaging appearance (ultrasonography, computed tomography [CT]) allows accurate prospective diagnosis. The recognition of this rare femoral hernia helps us to choose appropriate therapeutic approach. We report a case of an 81-year-old woman who present with painful and nonreducible groin mass. The ultrasonography and CT characteristic imaging features successfully diagnosed de Garengeot hernia. To our knowledge, this is the first description of a combination of CT and ultrasound in the preoperative diagnosis.