Alzheimer's disease (AD) is characterized by β‐amyloid (Aβ) deposition and Tau phosphorylation, in which its pathogenesis has not been cleared so far. The metabolism of Aβ and Tau is critically affected by the autophagy. Abnormal autophagy is thought to be involved in the pathogenesis of AD, regulating autophagy may become a new strategy for AD treatment. In the early stage of AD, the presence of Aβ and Tau can induce autophagy to promote their clearance by means of mTOR‐dependent and independent manners. As AD progress, the autophagy goes aberrant. As a result, Aβ and Tau generate continually, which aggravates both autophagy dysfunction and AD. Besides, several related genes and proteins of AD can also adapt autophagy to make an effect on the AD development. There seems to be a bi‐directional relationship between AD pathology and autophagy. At present, this article reviews this relationship from these aspects: (a) the signaling pathways of regulating autophagy; (b) the relationships between the autophagy and the processing of Aβ; (c) Aβ and Tau cause autophagy dysfunction; (d) normal autophagy promotes the clearance of Aβ and Tau; (e) the relationships between the autophagy and both genes and proteins related to AD: TFEB, miRNAs, Beclin‐1, Presenilin, and Nrf2; and (f) the small molecules regulating autophagy on AD therapy. All of the above may help to further elucidate the pathogenesis of AD and provide a theoretical basis for clinical treatment of AD.
Coxsackievirus B3 (CVB3) belongs to the genus Enterovirus of the family Picornaviridae and can cause acute acinar pancreatitis in adults. However, the molecular mechanisms of pathogenesis underlying CVB3-induced acute pancreatitis have remained unclear. In this study, we discovered that CVB3 capsid protein VP1 inhibited pancreatic cell proliferation and exerted strong cytopathic effects on HPAC cells. Through yeast two-hybrid, co-immunoprecipitation, and confocal microscopy, we show that Menage a trois 1 (MAT1), a subunit of the Cdk-Activating Kinase (CAK) complex involved in cell proliferation and transcription, is a novel interaction protein with CVB3 VP1. Moreover, CVB3 VP1 inhibited MAT1 accumulation and localization, thus interfering with its interaction with CDK7. Furthermore, CVB3 VP1 could suppress CAK complex enzymic phosphorylation activity towards RNA Pol II and CDK4/6, direct substrates of CAK. VP1 also suppresses phosphorylation of retinoblastoma protein (pRb), an indirect CAK substrate, especially at phospho-pRb Ser780 and phospho-pRb Ser807/811 residues, which are associated with cell proliferation. Finally, we present evidence using deletion mutants that the C-terminal domain (VP1-D8, 768-859aa) is the minimal VP1 region required for its interaction with MAT1, and furthermore, VP1-D8 alone was sufficient to arrest cells in G1/S phase as observed during CVB3 infection. Taken together, we demonstrate that CVB3 VP1 can inhibit CAK complex assembly and activity through direct interaction with MAT1, to block MAT1-mediated CAK-CDK4/6-Rb signaling, and ultimately suppress cell proliferation in pancreatic cells. These findings substantially extend our basic understanding of CVB3-mediated pancreatitis, providing strong candidates for strategic therapeutic targeting.
Shigellosis has become a serious threat to health in many developing countries due to the severe diarrhea it causes. Shigella flexneri 2a ( S. flexneri 2a) is the principal species responsible for this endemic disease. Despite multiple attempts to design a vaccine against shigellosis, no effective vaccine has not yet been developed. Lipopolysaccharide (LPS) is both an essential virulence factor and an antigen protective against Shigella , due to its outer domain, termed O-polysaccharide antigen. In the present study, S. flexneri 2a O-polysaccharide antigen was innovatively bio-synthesized in Salmonella and attached to core-lipid A via the ligase WaaL, with purified outer membrane vesicles (OMVs) utilized as vaccine vectors. Here, we identified the expression of the heterologous O-antigen and have described the isolation, characterization, and immune protection efficiency of the OMV vaccine. Furthermore, the results of animal experiments indicated that immunization of mice with the OMV vaccine both intranasally and intraperitoneally induced significant specific anti-Shigella LPS antibodies in the serum, with a similar trend IgA levels from vaginal secretions and fluid from bronchopulmonary lavage. The OMV vaccine derived from both routes of administration provided significant protection against virulent S. flexneri 2a infection, as judged by a serum bactericidal assay (SBA), opsonization assay, and challenge test. This vaccination strategy represents a novel and improved approach to control shigellosis by the combination of Salmonella glycosyl carrier lipid bioconjugation with OMVs. Importance: Shigella , the cause of shigellosis or bacillary dysentery, is a major public health concern, especially for children in developing countries. An effective vaccine would control the spread of the disease to some extent. However, no licensed vaccine against Shigella infection in humans has so far been developed. The Shigella O-antigen polysaccharide is effective in stimulating the production of protective antibodies and so could represent a vaccine antigen candidate. Additionally, bacterial outer membrane vesicles (OMVs) have been used as antigen delivery platforms due to their nanoscale properties and ease of antigen delivery to trigger an immune response. Therefore, the present study provides a new strategy for vaccine design, combining a glycoconjugated vaccine with OMVs. The design concept of this strategy is the expression of Shigella O-antigen via the LPS synthesis pathway in recombinant Salmonella , from which the OMV vaccine is then isolated. Based on these findings, we believe that the novel vaccine design strategy in which polysaccharide antigens are delivered via bacterial OMVs will be effective for the development and clinical application of an effective Shigella vaccine.
Colon cancer is the second leading cause of cancer-related death, and there are few effective therapies for colon cancer. This study explored the use of coxsackievirus group B3 (CVB3) as an oncolytic virus for the treatment of colon cancer. In this study, we verified that CVB3 induces death of colon cancer cell lines by directly observing cell morphology and Western blot results, and observed the oncolytic effects of CVB3 by constructing an immunodeficient nude mice model. Our data show that CVB3 induces pyroptosis in colon cancer cell lines. Mechanistically, we demonstrated that CVB3 causes cleavage of gasdermin E (GSDME), but not gasdermin D (GSDMD), by activating caspase-3. This leads to production of GSDME N-termini and the development of pores in the plasma membrane, inducing pyroptosis of colon cancer cell lines. We also demonstrate that CVB3-induced pyroptosis is promoted by reactive oxygen species (ROS). Finally, in vivo studies using immunodeficient nude mice revealed that intratumoral injection of CVB3 led to significant tumor regression. Our findings indicate that CVB3 has oncolytic activity in colon cancer cell lines via GSDME-mediated pyroptosis.
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