Tumor Suppressor DAPK1 Catalyzes Adhesion Assembly on Rigid but Anoikis on Soft Matrices.

Cancer cells normally grow on soft surfaces due to impaired mechanosensing of the extracellular matrix rigidity. Upon restoration of proper mechanosensing, cancer cells undergo apoptosis on soft surfaces (anoikis) like most normal cells. However, the link between mechanosensing and activation of anoikis is not clear. Here we show that death associated protein kinase 1 (DAPK1), a tumor suppressor that activates cell death, is directly linked to anoikis activation through rigidity sensing. We find that when rigidity sensing is decreased through inhibition of DAPK1 activity, cells are transformed for growth on soft matrices. Further, DAPK1 catalyzes matrix adhesion assembly and is part of adhesions on rigid surfaces. This pathway involves DAPK1 phosphorylation of tropomyosin1.1, the talin1 head domain, and tyrosine phosphorylation of DAPK1 by Src. On soft surfaces, DAPK1 rapidly dissociates from the adhesion complexes and activates apoptosis as catalyzed by PTPN12 activity and talin1 head. Thus, DAPK1 is important for adhesion assembly on rigid surfaces and the activation of anoikis on soft surfaces through its binding to rigidity-sensing modules.

Human Cytomegalovirus Particles Treated with Specific Antibodies Induce Intrinsic and Adaptive but Not Innate Immune Responses.

Human cytomegalovirus (HCMV) persistently infects 40% to 100% of the human population worldwide. Experimental and clinical evidence indicates that humoral immunity to HCMV plays an important role in restricting virus dissemination and protecting the infected host from disease. Specific immunoglobulin preparations from pooled plasma of adults selected for high titers of HCMV antibodies have been used for the prevention of CMV disease in transplant recipients and pregnant women. Even though incubation of HCMV particles with these preparations leads to the neutralization of viral infectivity, it is still unclear whether the antibody-treated HCMV particles (referred to here as HCMV-Ab) enter the cells and modulate antiviral immune responses. Here we demonstrate that HCMV-Ab did enter macrophages. HCMV-Ab did not initiate the expression of immediate early antigens (IEAs) in macrophages, but they induced an antiviral state and rendered the cells less susceptible to HCMV infection upon challenge. Resistance to HCMV infection seemed to be due to the activation of intrinsic restriction factors and was independent of interferons. In contrast to actively infected cells, autologous NK cells did not degranulate against HCMV-Ab-treated macrophages, suggesting that these cells may not be eliminated by innate effector cells. Interestingly, HCMV-Ab-treated macrophages stimulated the proliferation of autologous adaptive CD4+ and CD8+ T cells. Our findings not only expand the current knowledge on virus-antibody immunity but may also be relevant for future vaccination strategies.IMPORTANCE Human cytomegalovirus (HCMV), a common herpesvirus, establishes benign but persistent infections in immunocompetent hosts. However, in subjects with an immature or dysfunctional immune system, HCMV is a major cause of morbidity and mortality. Passive immunization has been used in different clinical settings with variable clinical results. Intravenous hyperimmune globulin preparations (IVIg) are obtained from pooled adult human plasma selected for high anti-CMV antibody titers. While HCMV neutralization can be shown in vitro using different systems, data are lacking regarding the cross-influence of IVIg administration on the cellular immune responses. The aim of this study was to evaluate the effects of IVIg on distinct components of the immune response against HCMV, including antigen presentation by macrophages, degranulation of innate natural killer cells, and proliferation of adaptive CD4+ and CD8+ T cells.

Phosphorylation and turnover of paxillin in focal contacts is controlled by force and defines the dynamic state of the adhesion site.

Micro-environmental clues are critical to cell behavior. One of the key elements of migration is the generation and response to forces. Up to now there is no definitive concept on how the generation and responses to cellular forces influence cell behavior. Here, we show that phosphorylation of paxillin is a crucial event in the response to exogenous forces. Application of force induced growth of adhesion sites and this phenomenon was accompanied by a downregulation of Src family kinase activity, which in turn led to a decrease in the phosphorylation of paxillin at the tyrosine residues Y31 and Y118. The force-dependent growth of adhesion sites is mediated by a decrease in the turnover-rate of paxillin in focal contacts. This turnover critically depended on the phosphorylation state of paxillin at Y31/118. Paxillin is an important regulator in the control of the aggregate state of the whole adhesion site since the turnover of other adhesion site proteins such as vinculin is influenced by the phosphorylation state of paxillin as well. Taken together these data suggest that SFK dependent phosphorylation of paxillin is a crucial event in the regulation of adhesion site function in response to force.

Regulatory T cells and their molecular markers in peripheral blood of the patients with systemic lupus erythematosus.

CD4(+)CD25(+) regulatory T cells (Tregs) and the expression of their molecular markers (GITR, Foxp3) in peripheral blood of the patients with systemic lupus erythematosus (SLE) were investigated in order to reveal the pathogenesis of SLE on the cellular and molecular levels. The level of Tregs in peripheral blood was detected by flow cytometry. The expression levels of GITR and Foxp3 mRNA in peripheral blood mononuclear cells (PBMCs) were assayed by reverse transcriptase-polymerase chain reaction (RT-PCR). The level of IL-6 in the plasma was measured by ELISA. Comparisons were made among 3 groups: the active SLE group, the inactive SLE group, and normal control group. The level of Tregs in the active SLE group and the inactive SLE group was significantly lower than in the normal control group (P<0.01). The level of Tregs in the active group was lower than in the inactive group with the difference being not significant (P>0.05). The level of Tregs in SLE patients was significantly negatively correlated with the disease active index in SLE (SLEDAI) (r=-0.81, P<0.01). The expression levels of GITR mRNA in PBMCs of the active SLE group and the inactive SLE group were significantly higher than in the normal control group (P<0.05), and those of Foxp3 mRNA in SLE patients of both active and inactive SLE groups were significantly lower than in the normal control group (P<0.05). There was no significant difference in the expression of GITR and Foxp3 mRNA between the active SLE group and inactive SLE group (P>0.05). The plasma levels of IL-6 in both the inactive SLE group and active SLE group were significantly higher than in the normal control group (P<0.01). The plasma level of IL-6 in the active SLE group was significantly increased as compared with that in the inactive SLE group (P<0.05), and the plasma level of IL-6 in SLE was significantly positively correlated with SLEDAI scores (r=0.58, P<0.01) and significantly negatively correlated with the ratio of CD4(+)CD25(+) cells/CD4(+) cells (r=-0.389, P<0.05). It was concluded that the levels of Tregs and Foxp3 mRNA in peripheral blood of SLE patients were decreased and the levels of GITR mRNA and plasma IL-6 were increased. The Tregs and their molecular markers GITR, Foxp3 as well as the plasma IL-6 might play an important role in the pathogenesis of SLE.

Regulatory T Cells and Their Molecular Markers in Peripheral Blood of the Patients with Systemic Lupus Erythematosus / 华中科技大学学报（医学）（英德文版）

Summary: CD4+CD25+ regulatory T cells (Tregs) and the expression of their molecular markers (GITR, Foxp3) in peripheral blood of the patients with systemic lupus erythematosus (SLE) were investigated in order to reveal the pathogenesis of SLE on the cellular and molecular levels. The level of Tregs in peripheral blood was detected by flow cytometry. The expression levels of GITR and Foxp3 mRNA in peripheral blood mononuclear cells (PBMCs) were assayed by reverse transcriptasepolymerase chain reaction (RT-PCR). The level of IL-6 in the plasma was measured by ELISA.Comparisons were made among 3 groups: the active SLE group, the inactive SLE group, and normal control group. The level of Tregs in the active SLE group and the inactive SLE group was significantly lower than in the normal control group (P<0.01). The level of Tregs in the active group was lower than in the inactive group with the difference being not significant (P>0.05). The level of Tregs in SLE patients was significantly negatively correlated with the disease active index in SLE (SLEDAI) (r=--0.81, P<0.01). The expression levels of GITR mRNA in PBMCs of the active SLE group and the inactive SLE group were significantly higher than in the normal control group (P<0.05), and those of Foxp3 mRNA in SLE patients of both active and inactive SLE groups were significantly lower than in the normal control group (P<0.05). There was no significant difference in the expression of GITR and Foxp3 mRNA between the active SLE group and inactive SLE group (P>0.05). The plasma levels of IL-6 in both the inactive SLE group and active SLE group were significantly higher than in the normal control group (P<0.01). The plasma level of IL-6 in the active S LE group was significantly increased as compared with that in the inactive SLE group (P<0.05), and the plasma level of IL-6 in SLE was significantly positively correlated with SLEDAI scores (r=0.58, P<0.01) and significantly negatively correlated with the ratio of CD4+CD25+ cells/CD4+ cells (r=-0.389, P<0.05). It was concluded that the levels of Tregs and Foxp3 mRNA in peripheral blood of SLE patients were decreased and the levels of GITR mRNA and plasma IL-6 were increased. The Tregs and their molecular markers GITR, Foxp3 as well as the plasma IL-6 might play an important role in the pathogenesis of SLE.