Accumulation of a soluble form of human nectin-2 is required for exerting the resistance against herpes simplex virus type 2 infection in transfected cells

A critical review on antiviral peptides derived from viral glycoproteins and host receptors to decoy herpes simplex virus

The health of the human population has been continuously challenged by viral infections. Herpes simplex virus (HSV) is one of the common causes of illness and can lead to death in immunocompromised patients. Existing anti-HSV therapies are not completely successful in eliminating the infection due to anti-viral drug resistance, ineffectiveness against the latent virus and high toxicity over prolonged use. There is a need to update our knowledge of the current challenges faced in anti-HSV therapeutics and realize the necessity of developing alternative treatment approaches. Protein therapeutics are now being explored as a novel approach due to their high specificity and low toxicity. This review highlights the significance of HSV viral glycoproteins and host receptors in the pathogenesis of HSV infection. Proteins or peptides derived from HSV glycoproteins gC, gB, gD, gH and host cell receptors (HSPG, nectin and HVEM) that act as decoys to inhibit HSV attachment, entry, or fusion have been discussed. Few researchers have tried to improve the efficacy and stability of the identified peptides by modifying them using a peptidomimetic approach. With these efforts, we think developing an alternative treatment option for immunocompromised patients and drug-resistant organisms is not far off.

A Systematic Review of Second-Line Treatments in Antiviral Resistant Strains of HSV-1, HSV-2, and VZV

Drug-resistant variants of herpes simplex viruses (HSV) have been reported that are not effectively treated with first-line antiviral agents. The objective of this study was to evaluate available literature on the possible efficacy of second-line treatments in HSV and the use of second-line treatments in HSV strains that are resistant to first-line treatments. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a final search was conducted in six databases on November 5, 2021 for all relevant literature using terms related to antiviral resistance, herpes, and HSV. Eligible manuscripts were required to report the presence of an existing or proposed second-line treatment for HSV-1, HSV-2, or varicella zoster virus (VZV); have full-text English-language access; and potentially reduce the rate of antiviral resistance. Following screening, 137 articles were included in qualitative synthesis. Of the included studies, articles that examined the relationship between viral resistance to first-line treatments and potential second-line treatments in HSV were included. The Cochrane risk-of-bias tool for randomized trials was used to assess risk of bias. Due to the heterogeneity of study designs, a meta-analysis of the studies was not performed. The dates in which accepted studies were published spanned from 2015-2021. In terms of sample characteristics, the majority (72.26%) of studies used Vero cells. When looking at the viruses on which the interventions were tested, the majority (84.67%) used HSV-1, with (34.31%) of these studies reporting testing on resistant HSV strains. Regarding the effectiveness of the proposed interventions, 91.97% were effective as potential managements for resistant strains of HSV. Of the papers reviewed, nectin in 2.19% of the reviews had efficacy as a second-line treatments in HSV, amenamevir in 2.19%, methanol extract in 2.19%, monoclonal antibodies in 1.46%, arbidol in 1.46%, siRNA swarms in 1.46%, Cucumis melo sulfated pectin in 1.46%, and components from Olea europeae in 1.46%. In addition to this griffithsin in 1.46% was effective, Morus alba L. in 1.46%, using nucleosides in 1.46%, botryosphaeran in 1.46%, monoterpenes in 1.46%, almond skin extracts in 1.46%, bortezomib in 1.46%, flavonoid compounds in 1.46%, andessential oils were effective in 1.46%, but not effective in 0.73%. The available literature reviewed consistently supports the existence and potentiality of second-line treatments for HSV strains that are resistant to first-line treatments. Immunocompromised patients have been noted to be the population most often affected by drug-resistant variants of HSV. Subsequently, we found that HSV infections in this patient population are challenging to manage clinically effectively. The goal of this systematic review is to provide additional information to patients on the potentiality of second-line treatment in HSV strains resistant to first-line treatments, especially those who are immunocompromised. All patients, whether they are immunocompromised or not, deserve to have their infections clinically managed in a manner supported by comprehensive research. This review provides necessary information about treatment options for patients with resistant HSV infections and their providers.

Identification of pleiotropic genes between risk factors of stroke by multivariate metaCCA analysis

Genome-wide association studies (GWASs) have identified more than 20 genetic loci as risk predictors associated with stroke. However, these studies were generally performed for single-trait and failed to consider the pleiotropic effects of these risk genes among the multiple risk factors for stroke. In this study, we applied a novel metaCCA method followed by gene-based VEGAS2 analysis to identify the risk genes for stroke that may overlap between seven correlated risk factors (including atrial fibrillation, hypertension, coronary artery disease, heart failure, diabetes, body mass index, and total cholesterol level) by integrating seven corresponding GWAS data. We detected 20 potential pleiotropic genes that may be associated with multiple risk factors of stroke. Furthermore, using gene-to-trait pathway analysis, we suggested six potential risk genes (FUT8, GMIP, PLA2G6, PDE3A, SMARCA4, SKAPT) that may affect ischemic or hemorrhage stroke through multiple intermediate factors such as MAPK family. These findings provide novel insight into the genetic determinants contributing to the concurrent development of biological conditions that may influence stroke susceptibility, and also indicate some potential therapeutic targets that can be further studied for the prevention of cerebrovascular disease.

Identification of Potential Immune-Related circRNA-miRNA-mRNA Regulatory Network in Intestine of Paralichthys olivaceus During Edwardsiella tarda Infection

Olive flounder (Paralichthys olivaceus) is an important economical flatfish in Japan, Korea, and China, but its production has been greatly threatened by disease outbreaks. In this research, we aimed to explore the immune responsive mechanism of P. olivaceus against Edwardsiella tarda infection by profiling the expression of circRNA, miRNA, and mRNA by RNA-seq and constructing a regulatory circular circRNA–miRNA–mRNA network. Illumina sequencing of samples from normal control (H0), 2 h (H2), 8 h (H8), and 12 h (H12) post-challenge was conducted. Differentially expressed (DE) circRNA (DE–circRNAs), miRNAs (DE–miRNAs), and mRNAs [differential expression genes (DEGs)] between challenge and control groups were identified, resulting in a total of 62 DE–circRNAs, 39 DE–miRNAs, and 3,011 DEGs. Based on the differentially expressed gene results, miRNA target interactions (circRNA–miRNA pairs and miRNA–mRNA pairs) were predicted by MiRanda software. Once these paired were combined, a preliminary circRNA–miRNA–mRNA network was generated with 198 circRNA–miRNA edges and 3,873 miRNA–mRNA edges, including 44 DE–circRNAs, 32 DE–miRNAs, and 1,774 DEGs. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was performed to evaluate the function of the DEGs in this network, and we focused and identified two important intestinal immune pathways (herpes simplex infection and intestinal immune network for IgA production) that showed statistical significance between the challenge and control groups. Furthermore, three critical DEGs (nectin2, MHC II α-chain, and MHC II β-chain) were identified, mapped into the preliminary circRNA–miRNA–mRNA network, and new circRNA–miRNA–mRNA regulatory networks were constructed. In conclusion, we, for the first time, identified circRNA–miRNA–mRNA network from P. olivaceus in the pathogenesis of E. tarda and provided valuable resources for further analyses of the molecular mechanisms and signaling networks.

Implication of Soluble Forms of Cell Adhesion Molecules in Infectious Disease and Tumor: Insights from Transgenic Animal Models

Cell adhesion molecules (CAMs) are surface ligands, usually glycoproteins, which mediate cell-to-cell adhesion. They play a critical role in maintaining tissue integrity and mediating migration of cells, and some of them also act as viral receptors. It has been known that soluble forms of the viral receptors bind to the surface glycoproteins of the viruses and neutralize them, resulting in inhibition of the viral entry into cells. Nectin-1 is one of important CAMs belonging to immunoglobulin superfamily and herpesvirus entry mediator (HVEM) is a member of the tumor necrosis factor (TNF) receptor family. Both CAMs also act as alphaherpesvirus receptor. Transgenic mice expressing the soluble form of nectin-1 or HVEM showed almost complete resistance against the alphaherpesviruses. As another CAM, sialic acid-binding immunoglobulin-like lectins (Siglecs) that recognize sialic acids are also known as an immunoglobulin superfamily member. Siglecs play an important role in the regulation of immune cell functions in infectious diseases, inflammation, neurodegeneration, autoimmune diseases and cancer. Siglec-9 is one of Siglecs and capsular polysaccharide (CPS) of group B Streptococcus (GBS) binds to Siglec-9 on neutrophils, leading to suppress host immune response and provide a survival advantage to the pathogen. In addition, Siglec-9 also binds to tumor-produced mucins such as MUC1 to lead negative immunomodulation. Transgenic mice expressing the soluble form of Siglec-9 showed significant resistance against GBS infection and remarkable suppression of MUC1 expressing tumor proliferation. This review describes recent developments in the understanding of the potency of soluble forms of CAMs in the transgenic mice and discusses potential therapeutic interventions that may alter the outcomes of certain diseases.

Comparison of the antiviral potential among soluble forms of herpes simplex virus type-2 glycoprotein D receptors, herpes virus entry mediator A, nectin-1 and nectin-2, in transgenic mice

Herpesvirus entry mediator A (HVEM), nectin-1 and nectin-2 are cellular receptors of glycoprotein D (gD) of herpes simplex virus type-2 (HSV-2). It has been shown that soluble forms of HSV gD receptors have the antiviral potential in cultured cells and transgenic mice. Here, to compare antiviral potential of soluble forms of HVEM, nectin-1 and nectin-2 against HSV-2 infections in vivo, transgenic mice expressing fusion proteins consisting of the entire ectodomain of HVEM, nectin-1 or nectin-2 and the Fc portion of human IgG (HVEMIg, nectin-1Ig and nectin-2Ig, respectively) were intraperitoneally infected with HSV-2. In the infection with 3 MLD50 (50 % mouse lethal dose), effective resistance was not observed in transgenic mice expressing nectin-2Ig. In a transgenic mouse line with high expression of nectin-1Ig, significant protection from the infection with 30 and 300 MLD50 was observed (survival rate of 100 and 71 %, respectively). On the other hand, transgenic mice expressing HVEMIg showed a complete resistance to the lethal infection even with 300 MLD50 (survival rate of 100 %). These results demonstrated that HVEMIg could exert effective antiviral activities against HSV-2 infections in vivo as compared with other soluble forms of HSV gD receptors.