Palatal perforation caused by Alternaria alternata infection in an immunocompetent adolescent.

Opportunistic oral mucosal fungal infection caused by Alternaria alternata is extremely rare. Herein, we present a rare palatal perforation as a result of oral infection caused by A. alternata in an immunocompetent adolescent. An 18-year-old boy, who had previously been healthy, was admitted to our institution with persistent pain in the palate for the past 12 months. Upon impression of palatal bone resorption based on computed tomography imaging and chronic granulomatous inflammation based on biopsy (hematoxylin-eosin staining), the patient was examined for commonly relevant causes such as potential tumor and Mycobacterium tuberculosis infection. All test results were inconclusive. After a thorough diagnostic investigation, an unusual fungal infection, A. alternata infection, was confirmed by next-generation sequencing and biopsy (periodic acid-Schiff staining and immunofluorescence staining). The patient underwent surgical debridement and was subjected to voriconazole treatment postoperatively for over a period of 5 months. Thus, these findings highlight the importance of considering A. alternata as a potential pathogenic factor in an etiological palatal perforation.

Oxidized mitochondrial DNA induces gasdermin D oligomerization in systemic lupus erythematosus.

Although extracellular DNA is known to form immune complexes (ICs) with autoantibodies in systemic lupus erythematosus (SLE), the mechanisms leading to the release of DNA from cells remain poorly characterized. Here, we show that the pore-forming protein, gasdermin D (GSDMD), is required for nuclear DNA and mitochondrial DNA (mtDNA) release from neutrophils and lytic cell death following ex vivo stimulation with serum from patients with SLE and IFN-γ. Mechanistically, the activation of FcγR downregulated Serpinb1 following ex vivo stimulation with serum from patients with SLE, leading to spontaneous activation of both caspase-1/caspase-11 and cleavage of GSDMD into GSDMD-N. Furthermore, mtDNA oxidization promoted GSDMD-N oligomerization and cell death. In addition, GSDMD, but not peptidyl arginine deiminase 4 is necessary for extracellular mtDNA release from low-density granulocytes from SLE patients or healthy human neutrophils following incubation with ICs. Using the pristane-induced lupus model, we show that disease severity is significantly reduced in mice with neutrophil-specific Gsdmd deficiency or following treatment with the GSDMD inhibitor, disulfiram. Altogether, our study highlights an important role for oxidized mtDNA in inducing GSDMD oligomerization and pore formation. These findings also suggest that GSDMD might represent a possible therapeutic target in SLE.

Lithium chloride confers protection against viral myocarditis via suppression of coxsackievirus B3 virus replication.

Viral myocarditis (VMC) is a type of inflammation affecting myocardial cells caused by viral infection and has been an important cause of dilated cardiomyopathy (DCM) worldwide. Type B3 coxsackievirus (CVB3), a non-enveloped positive-strand RNA virus of the Enterovirus genus, is one of most common agent of viral myocarditis. Till now, effective treatments for VMC are lacking due to lack of drugs or vaccine. Lithium chloride (LiCl) is applied in the clinical management of manic depressive disorders. Accumulating evidence have demonstrated that LiCl, also as an effective antiviral drug, exhibited antiviral effects for specific viruses. However, there are few reports of evaluating LiCl's antiviral effect in mice model. Here, we investigated the inhibitory influence of LiCl on the CVB3 replication in vitro and in vivo and the development of CVB3-induced VMC. We found that LiCl significantly suppressed CVB3 replication in HeLa via inhibiting virus-induced cell apoptosis. Moreover, LiCl treatment in vivo obviously inhibited virus replication within the myocardium and alleviated CVB3-induced acute myocarditis. Collectively, our data demonstrated that LiCl inhibited CVB3 replication and negatively regulated virus-triggered inflammatory responses. Our finding further expands the antiviral targets of LiCl and provides an alternative agent for viral myocarditis.

Pathogenic Role of an IL-23/γδT17/Neutrophil Axis in Coxsackievirus B3-Induced Pancreatitis.

Coxsackievirus B is a common cause of viral myocarditis and pancreatitis. IL-17A is intensively involved in the pathogenesis of viral myocarditis. Whether IL-17A plays a role in Coxsackievirus B-induced pancreatitis, characterized by acinar cell destruction and immune infiltration, remains largely unknown. We found a significant, but transient, increase of IL-17A expression and γδT influx in the pancreas of C57BL/6J mice within 3 d following CVB3 infection. The pancreatic IL-17A was mainly produced by Vγ4 γδ T cells, to a lesser extent by CD4+ Th17 cells. IL-17A-/- and TCRδ-/- mice both reduced their susceptibility to CVB3 infection and pancreatitis severity when compared with the wild-type mice, without altering viral load. mAb depletion of Vγ4γδ T cells significantly improved mice survival and pancreatic pathology via decreasing Th17 expansion and neutrophil influx into the pancreas compared with isotype-treated mice. Transfer of Vγ4γδ T cells from wild-type, but not IL-17-/-, mice reconstituted TCRδ-/- mice to produce IL-17 and develop pancreatitis to the level of wild-type mice during CVB3 infection, indicating γδ T IL-17A is required for the onset of viral pancreatitis. IL-23 was robustly induced in the pancreas within the first day of infection. Administration of exogenous rIL-23 to mice increased CVB3 pancreatitis through in vivo expansion of IL-17+γδT17 cells at 12 h postinfection. Our findings reveal a key pathogenic role for early-activated γδT17 cells in viral pancreatitis via promoting neutrophil infiltration and Th17 induction. This IL-23/γδT17/neutrophil axis is critically involved in the onset of CVB3 pancreatitis and represents a potential treating target for the disease.

MCPIP1 inhibits coxsackievirus B3 replication by targeting viral RNA and negatively regulates virus-induced inflammation.

Monocyte chemotactic protein-induced protein 1(MCPIP1) is identified as an important inflammatory regulator during immune response. MCPIP1 possesses antiviral activities against several viruses, such as Japanese encephalitis. However, its role on Coxsackievirus B3 (CVB3) infection, a positive-stranded RNA virus, has not been addressed. Here, we reported that MCPIP1 was up-regulated in cardiomyocytes by CVB3 infection and in hearts and pancreas of infected mice. Then we found that overexpression of MCPIP1 inhibited CVB3 replication and knockdown of it promoted virus replication. Luciferase assay demonstrated MCPIP1 targeting non-ARE region of CVB3 3'UTR, which was dependent on its RNase, RNA binding and oligomerization abilities, but not deubiquitinase activity. We further verified that MCPIP1 negatively regulated CVB3-induced inflammatory response in macrophages. Thus, our data suggest MCPIP1 as a potent host defense against CVB3 infection and viral myocarditis.

Vγ1+γδT, early cardiac infiltrated innate population dominantly producing IL-4, protect mice against CVB3 myocarditis by modulating IFNγ+ T response.

Viral myocarditis (VMC) is an inflammation of the myocardium closely associated with Coxsackievirus B3 (CVB3) infection. Vγ1+γδT cells, one of early cardiac infiltrated innate population, were reported to protect CVB3 myocarditis while the precise mechanism not fully addressed. To explore cytokine profiles and kinetics of Vγ1+γδT and mechanism of protection against VMC, flow cytometry was conducted on cardiac Vγ1 cells in C57BL/6 mice following CVB3 infection. The level of cardiac inflammation, transthoracic echocardiography and viral replication were evaluated after monoclonal antibody depletion of Vγ1γδT. We found that Vγ1+γδT cells infiltration peaked in the heart at day3 post CVB3 infection and constituted a minor source of IFN-γ but major producers for early IL-4. Vγ1γδT cells were activated earlier holding a higher IL-4-producing efficiency than CD4+Th cells in the heart. Depletion of Vγ1+γδT resulted in a significantly exacerbated cardiac infiltration, increased T, macrophage and neutrophil population in heart homogenates and worse cardiomyopathy; which was accompanied by a significant expansion of peripheral IFNγ+CD4+ and CD8+T cells. Neutralization of IL-4 in mice resulted in an exacerbated acute myocarditis confirming the IL-4-mediated protective mechanism of Vγ1. Our findings identify a unique property of Vγ1+γδT cells as one dominant early producers of IL-4 upon CVB3 acute infection which is a key mediator to protect mice against acute myocarditis by modulating IFNγ-secreting T response.

Zinc finger antiviral protein inhibits coxsackievirus B3 virus replication and protects against viral myocarditis.

The host Zinc finger antiviral protein (ZAP) has been reported exhibiting antiviral activity against positive-stranded RNA viruses (Togaviridae), negative-stranded RNA viruses (Filoviridae) and retroviruses (Retroviridae). However, whether ZAP restricts the infection of enterovirus and the development of enterovirus mediated disease remains unknown. Here, we reported the antiviral properties of ZAP against coxsackievirus B3 (CVB3), a single-stranded RNA virus of the Enterovirus genus within the Picornaviridae as a major causative agent of viral myocarditis (VMC). We found that the expression of ZAP was significantly induced after CVB3 infection in heart tissues of VMC mice. ZAP potently inhibited CVB3 replication in cells after infection, while overexpression of ZAP in mice significantly increased the resistance to CVB3 replication and viral myocarditis by significantly reducing cardiac inflammatory cytokine production. The ZAP-responsive elements (ZREs) were mapped to the 3'UTR and 5'UTR of viral RNA. Taken together, ZAP confers resistance to CVB3 infection via directly targeting viral RNA and protects mice from acute myocarditis by suppressing viral replication and cardiac inflammatory cytokine production. Our finding further expands ZAP's range of viral targets, and suggests ZAP as a potential therapeutic target for viral myocarditis caused by CVB3.