Neuritogenesis, or neurite outgrowth, is a critical process for neuronal differentiation and maturation in which growth cones are formed from highly dynamic actin structures. Gas7 (growth arrest-specific gene 7), a new member of the PCH (Pombe Cdc15 homology) protein family, is predominantly expressed in neurons and is required for the maturation of primary cultured Purkinje neurons as well as the neuron-like differentiation of PC12 cells upon nerve growth factor stimulation. We report that Gas7 co-localizes and physically interacts with N-WASP, a key regulator of Arp2/3 complex-mediated actin polymerization, in the cortical region of Gas7-transfected Neuro-2a cells and growth cones of hippocampal neurons. The interaction between Gas7 and N-WASP is mediated by WW-Pro domains, which is unique in the PCH protein family, where most interactions are of the SH3-Pro kind. The interaction contributes to the formation of membrane protrusions and processes by recruiting the Arp2/3 complex in a Cdc42-independent manner. Importantly, specific interaction between Gas7 and N-WASP is required for regular neurite outgrowth of hippocampal neurons. The data demonstrate an essential role of Gas7 through its interaction with N-WASP during neuronal maturation/differentiation.

Aims To use experimental periodontitis models in rats to investigate the correlation between local expression of the complement components C3b and C4b in periodontal tissues and disease severity, and to assess the therapeutic effects of targeting C3b/C4b on inflammatory bone loss. Materials and Methods The gingival expression of C3, C3b, and C4b in animal experimental periodontitis models were analysed immunohistochemically. The therapeutic effects of the C3b/C4b inhibitor (SB002) on ligation‐induced experimental periodontitis was examined using biochemical, histological, and immunohistochemical analyses. Results The gingival expression levels of C3, C3b, and C4b were positively correlated with the severity of periodontitis. Moreover, both single and multiple injections of the C3b/C4b inhibitor had preventive and therapeutic effects on alveolar bone loss in ligation‐induced experimental periodontitis with no associated adverse consequences. Conclusions The association between C3b/C4b and periodontitis may provide a basis for the development of novel therapeutic strategies for periodontitis and other inflammatory diseases.

Background Bispecific antibody has garnered considerable attention in the recent years due to its impressive preliminary efficacy in hematological malignancies. For solid tumors, however, the main hindrance is the suppressive tumor microenvironment, which effectively impedes the activation of infiltrating T cells. Herein, we designed a bispecific antibody AP203 with high binding affinity to PD-L1 and CD137 and assessed its safety and anti-tumor efficacy, as well as explored the mechanism of action. Methods The optimal antibody binders against PD-L1 and CD137 were screened from the OmniMab phagemid library. The binding affinity of the constructed AP203 were evaluated using enzyme-linked immunosorbent assay (ELISA) and biolayer interferometry (BLI). T-cell stimulatory capacity was assessed using the allogeneic mixed lymphocyte reaction (MLR), antigen-specific recall response, and coculture with PD-L1-expressing cells. In vivo antitumor efficacy was evaluated using two models of tumor-xenografted humanized mice with profiling of tumor infiltrating lymphocytes (TILs). The possible toxicity of AP203 was examined using in vitro cytokine release assay by human PBMCs. Results AP203, which simultaneously targeted PD-L1 and costimulatory CD137, elicit superior agonistic effects over parental antibodies alone or in combination in terms of T cell activation, enhanced memory recall responses, and overcoming Treg-mediated immunosuppression (P < 0.05). The agonistic activity of AP203 was further demonstrated PD-L1-dependent by coculturing T cells with PD-L1-expressing cells. In vivo animal studies using immunodeficient or immunocompetent mice both showed a dose-related antitumor efficacy superior to parental antibodies in combination (P < 0.05). Correspondingly, AP203 significantly increased tumor infiltrating CD8 + T cells, while decreased CD4 + T cells, as well as Treg cells (P < 0.05), resulting in a dose-dependent increase in the CD8 + /CD4 + ratio. Moreover, either soluble or immobilized AP203 did not induce the production of inflammatory cytokines by human PBMCs. Conclusions AP203 exerts potent antitumor activity not only by blocking PD-1/PD-L1 inhibitory signaling, but also by activating CD137 costimulatory signaling in effector T cells that consequently counteracts Treg-mediated immunosuppression. Based on promising preclinical results, AP203 should be a suitable candidate for clinical treatment of solid tumors.

ObjectiveThis study aimed to investigate the correlation between the expression levels of C3b and C4b in human gingival tissue (GT) and gingival crevicular fluid (GCF) and disease severity in human periodontitis and to determine whether C3b and C4b are significant site‐specific complementary diagnostic markers for periodontitis.BackgroundA variety of biomarkers that have potential for informing diagnoses of periodontitis have been proposed. The complement components C3b and C4b were found to be positively correlated with disease severity. The therapeutic effect of targeting C3b and C4b on inflammatory bone loss in experimental periodontitis models has been studied. However, studies on the diagnostic potential of the gingival C3b and C4b expression levels for periodontitis are scarce.MethodsThe expression levels of C3b and C4b in the GT and GCF were investigated via immunohistochemistry and enzyme‐linked immunosorbent assay, respectively. The correlation between the expression levels of C3b and C4b and disease severity with probing depth as well as the clinical attachment level were determined. To evaluate the diagnostic accuracy of the C3b and C4b expression levels at the periodontitis sites, the receiver operating characteristic (ROC) curve, cut‐off point, area under the ROC curve, sensitivity, and specificity were analyzed.ResultsThe expression levels of C3b and C4b in human GT and GCF were significantly positively correlated with periodontitis severity. The expression levels of combined C3b + C4b in the GT can significantly differentiate the disease status at the tissue level (p < .0001). Similarly, the expression levels of C3b + C4b in GCF can statistically distinguish periodontitis sites from healthy ones (p < .0001).ConclusionsLocally deposited C3b and C4b were positively correlated with periodontitis severity and recognized as site‐specific diagnostic biomarkers for clinicopathological features in periodontitis. The association between the C3b and C4b network and periodontitis may be further understood and provide a basis for the development of novel screening as well as diagnostic and therapeutic strategies for periodontitis.