Carrier-free mRNA vaccine induces robust immunity against SARS-CoV-2 in mice and non-human primates without systemic reactogenicity

Carrier-free naked mRNA vaccines may reduce the reactogenicity associated with delivery carriers; however, their effectiveness against infectious diseases has been suboptimal. To boost efficacy, we targeted the skin layer rich in antigen-presenting cells (APCs) and utilized a jet injector. The jet injection efficiently introduced naked mRNA into skin cells, including APCs in mice. Further analyses indicated that APCs, after taking up antigen mRNA in the skin, migrated to the lymph nodes (LNs) for antigen presentation. Additionally, the jet injection provoked localized lymphocyte infiltration in the skin, serving as a physical adjuvant for vaccination. Without a delivery carrier, our approach confined mRNA distribution to the injection site, preventing systemic mRNA leakage and associated systemic proinflammatory reactions. In mouse vaccination, the naked mRNA jet injection elicited robust antigen-specific antibody production over 6 months, along with germinal center formation in LNs and the induction of both CD4- and CD8-positive T cells. By targeting the SARS-CoV-2 spike protein, this approach provided protection against viral challenge. Furthermore, our approach generated neutralizing antibodies against SARS-CoV-2 in non-human primates at levels comparable to those observed in mice. In conclusion, our approach offers a safe and effective option for mRNA vaccines targeting infectious diseases.

SARS-CoV-2 induces inflammation and intracranial infection through the olfactory epithelium-olfactory bulb pathway in non-human primates

We examined the histopathological changes in the olfactory mucosa of cynomolgus and rhesus macaque models of SARS-CoV-2 infection. SARS-CoV-2 infection induced severe inflammatory changes in the olfactory mucosa. A major histocompatibility complex (MHC) class II molecule, HLA-DR was expressed in macrophage and supporting cells, and melanocytes were increased in olfactory mucosa. Supporting cells and olfactory neurons were infected, and SARS-CoV-2 N protein was detected in the axons of olfactory neurons and in olfactory bulbs. Viral RNA was detected in olfactory bulbs and brain tissues. The olfactory epithelium-olfactory bulb pathway may be important as a route for intracranial infection by SARS-CoV-2.

Suppression of dengue virus replication by the French maritime pine extract Pycnogenol®

Dengue virus (DENV) is mainly found in the tropics and infects approximately 400 million people annually. However, no clinically available therapeutic agents specific to dengue have been developed. Here, we examined the potential antiviral effects of the French maritime pine extract Pycnogenol® (PYC) against DENV because we previously found that the extract exerts antiviral effects on hepatitis C virus, which belongs to the Flavivirus family. First, we examined the efficacy of PYC against DENV1, 2, 3, and 4 serotypes and determined that it had a dose-dependent suppressive effect on the viral load, especially in the supernatant. This inhibitory effect of PYC may target the late stages of infection such as maturation and secretion, but not replication. Next, we examined the efficacy of PYC against DENV infection in type I interferon (IFN) receptor knockout mice (A129). As the propagation of DENV2 was the highest among the four serotypes, we used this serotype in our murine model experiments. We found that PYC significantly inhibited DENV2 replication in mice on day 4 without significantly decreasing body weight or survival ratio. We further examined the mechanism of action of PYC in DENV2 infection by characterizing the main PYC targets among the host (viral) factors and silencing them using siRNA. Silencing long noncoding-interferon-induced protein (lnc-IFI)-44, polycystic kidney disease 1-like 3 (Pkd1l3), and ubiquitin-specific peptidase 31 (Usp31) inhibited the replication of DENV2. Thus, the results of this study shed light on the inhibitory effects of PYC on DENV replication and its underlying mechanisms.

A small molecule iCDM-34 identified by in silico screening suppresses HBV DNA through activation of aryl hydrocarbon receptor

IFN-alpha have been reported to suppress hepatitis B virus (HBV) cccDNA via APOBEC3 cytidine deaminase activity through interferon signaling. To develop a novel anti-HBV drug for a functional cure, we performed in silico screening of the binding compounds fitting the steric structure of the IFN-alpha-binding pocket in IFNAR2. We identified 37 compounds and named them in silico cccDNA modulator (iCDM)-1-37. We found that iCDM-34, a new small molecule with a pyrazole moiety, showed anti-HCV and anti-HBV activities. We measured the anti-HBV activity of iCDM-34 dependent on or independent of entecavir (ETV). iCDM-34 suppressed HBV DNA, pgRNA, HBsAg, and HBeAg, and also clearly exhibited additive inhibitory effects on the suppression of HBV DNA with ETV. We confirmed metabolic stability of iCDM-34 was stable in human liver microsomal fraction. Furthermore, anti-HBV activity in human hepatocyte-chimeric mice revealed that iCDM-34 was not effective as a single reagent, but when combined with ETV, it suppressed HBV DNA compared to ETV alone. Phosphoproteome and Western blotting analysis showed that iCDM-34 did not activate IFN-signaling. The transcriptome analysis of interferon-stimulated genes revealed no increase in expression, whereas downstream factors of aryl hydrocarbon receptor (AhR) showed increased levels of the expression. CDK1/2 and phospho-SAMHD1 levels decreased under iCDM-34 treatment. In addition, AhR knockdown inhibited anti-HCV activity of iCDM-34 in HCV replicon cells. These results suggest that iCDM-34 decreases the phosphorylation of SAMHD1 through CDK1/2, and suppresses HCV replicon RNA, HBV DNA, and pgRNA formation.

TLR agonists as vaccine adjuvants in the prevention of viral infections: an overview

Tol-like receptor (TLR) agonists, as potent adjuvants, have gained attention in vaccine research for their ability to enhance immune responses. This study focuses on their application in improving vaccine efficacy against key viral infections, including hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), SARS-CoV-2, influenza virus, and flaviviruses, including West Nile virus, dengue virus, and chikungunya virus. Vaccines are crucial in preventing microbial infections, including viruses, and adjuvants play a vital role in modulating immune responses. However, there are still many diseases for which effective vaccines are lacking or have limited immune response, posing significant threats to human health. The use of TLR agonists as adjuvants in viral vaccine formulations holds promise in improving vaccine effectiveness. By tailoring adjuvants to specific pathogens, such as HBV, HCV, HIV, SARS-CoV-2, influenza virus, and flavivirus, protective immunity against chronic and emerging infectious disease can be elicited.

A Novel, Comprehensive A129 Mouse Model for Investigating Dengue Vaccines and Evaluating Pathogenesis

In search of a mouse model for use in evaluating dengue vaccines, we assessed A129 mice that lacked IFN-α/β receptors, rendering them susceptible to dengue virus (DENV) infection. To our knowledge, no reports have evaluated dengue vaccine efficiency using A129 mice. A129 mice were given a single intraperitoneal (IP) or subcutaneous (SC) injection of the vaccine, Dengvaxia. After 14 days of immunization via the IP or SC injection of Dengvaxia, the A129 mice exhibited notably elevated levels of anti-DENV immunoglobulin G and neutralizing antibodies (NAb) targeting all four DENV serotypes, with DENV-4 displaying the highest NAb levels. After challenge with DENV-2, Dengvaxia and mock-immunized mice survived, while only the mock group exhibited signs of morbidity. Viral genome levels in the serum and tissues (excluding the brain) were considerably lower in the immunized mice compared to those in the mock group. The SC administration of Dengvaxia resulted in lower viremia levels than IP administration did. Therefore, given that A129 mice manifest dengue-related morbidity, including viremia in the serum and other tissues, these mice represent a valuable model for investigating novel dengue vaccines and antiviral drugs and for exploring dengue pathogenesis.

Effects of neddylation on viral infection: an overview

Neddylation is a post-translational modification that plays an important role not only in cancer development but also in regulating viral infection and replication. Upregulation of neddylation occurs in viral infections, and inhibition of neddylation can suppress viral replication. Neddylation is thought to enhance viral protein stability and replication. Neddylation has been reported to enhance the stability of the regulatory hepatitis B virus (HBV) X protein, modulate viral replication, and enhance hepatocarcinogenesis. Inhibition of neddylation using the NEDD8-activating enzyme E1 inhibitor MLN4924 inhibits viral replication, including that of HBV. Understanding of the role of neddylation in viral infections is critical for developing new therapeutic targets and potential treatment strategies. In this review, we discuss recent progress in the understanding of the effects of neddylation during viral infection, particularly in HBV infection, and strategies for curing viral infection by targeting the neddylation pathway.

Hybrid large hepatitis B surface protein composed of two viral genotypes C and D induces strongly cross-neutralizing antibodies

Hepatitis B virus (HBV) vaccination is known to effectively decrease the risk of HBV infection. However, several issues need to be addressed in order to develop an improved HBV vaccine. Although the HBV vaccine has been shown to be effective, this vaccine needs to be more efficacious in defined groups, including non-responders (i.e., individuals who do not develop a protective response even after vaccination) and in health care workers and travelers who require rapid protection. Furthermore, it has been reported that universal HBV vaccination has accelerated the appearance of vaccine-escape mutants resulting from the accumulation of mutations altering the "a" determinant of the hepatitis B surface (HBs) protein. To address these problems, we have been focusing on the large HBs (LHBs) protein, which consists of three domains: pre-S1, pre-S2, and S (in N- to C-terminal order). To enhance the immunogenicity of LHBs, we developed a yeast-derived hybrid LHBs (hy-LHBs) antigen composed of the LHBs proteins from two distinct genotypes (Genotypes C and D). The levels of antibodies induced by hy-LHBs immunization were high not only against S, but also against the pre-S1 and pre-S2 domains. Additionally, hy-LHBs immunization induced significantly more strongly cross-reactive neutralizing antibodies than did small HBs (SHBs) or LHBs of any genotype alone. These findings suggested that hy-LHBs might serve as a candidate antigen for use in an improved prophylactic HBV vaccine.

Molecular insights of a CBP/β-catenin-signaling inhibitor on nonalcoholic steatohepatitis-induced liver fibrosis and disorder

Nonalcoholic steatohepatitis (NASH) is a progressive fibrotic disease associated with an increased risk of developing hepatocellular carcinoma; at present, no efficient therapeutic strategy has been established. Herein, we examined the efficacy of PRI-724, a potent inhibitor of CBP/β-catenin signaling, for treating NASH-related liver fibrosis and disorder and characterized its mechanism. Choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD)-fed mice exhibited NASH-induced liver fibrosis that is characterized by steatosis, lobular inflammation, hepatocellular injury and collagen fibrils. To examine the therapeutic effect, CDAHFD-fed mice were administered PRI-724. Serum levels of ALT and pro-fibrotic molecule, i.e. Mac-2 bp, alpha smooth muscle actin, type I and type III collagens, decreased significantly. mRNA levels of the matrix metalloproteinases Mmp8 and Mmp9 in the liver were significantly increased, and increases in the abundance of MMP9-producing neutrophils and macrophages were observed. Marco+Mmp9+Cd68+ Kupffer cells were only observed in the livers of mice treated with PRI-724, and Mmp9 expression in Marco+Cd68+ Kupffer cells increased 4.3-fold. Moreover, hepatic expression of the lipid metabolism regulator, pyruvate dehydrogenase kinase 4 and liver lipid droplets also decreased significantly. PRI-724-treated NASH mice not only recovered from NASH-related liver fibrosis through the effect of PRI-724 down-regulating the expression of pro-fibrotic genes and up-regulating the expression of anti-fibrotic genes, but they also recovered from NASH-induced liver disorder. PRI-724, a selective CBP/β-catenin inhibitor, thus shows a potent therapeutic effect for NASH-related liver fibrosis and for decreasing adipose tissue in the liver.

Intranasal HBsAg/HBcAg-Containing Vaccine Induces Neutralizing Anti-HBs Production in Hepatitis B Vaccine Non-Responders

Hepatitis B vaccine induces the production of antibodies against hepatitis B surface antigen (anti-HBs) and prevents hepatitis B virus (HBV) infection. However, 5-10% of individuals cannot develop anti-HBs even after multiple vaccinations (HB vaccine non-responders). We developed an intranasal vaccine containing both HBs antigen (HBsAg) and HB core antigen (HBcAg) and mixed it with a viscosity enhancer, carboxyl vinyl polymer (CVP-NASVAC). Here, we investigated the prophylactic capacity of CVP-NASVAC in HB vaccine non-responders. Thirty-four HB vaccine non-responders were administered three doses of intranasal CVP-NASVAC. The prophylactic capacity of CVP-NASVAC was assessed by evaluating the induction of anti-HBs and anti-HBc (IgA and IgG) production, HBV-neutralization activity of sera, and induction of HBs- and HBc-specific cytotoxic T lymphocytes (CTLs). After CVP-NASVAC administration, anti-HBs and anti-HBc production were induced in 31/34 and 27/34 patients, respectively. IgA anti-HBs and anti-HBc titers significantly increased after CVP-NASVAC vaccination. HBV-neutralizing activity in vitro was confirmed in the sera of 26/29 CVP-NASVAC-administered participants. HBs- and HBc-specific CTL counts substantially increased after the CVP-NASVAC administration. Mild adverse events were observed in 9/34 participants; no serious adverse events were reported. Thus, CVP-NASVAC could be a beneficial vaccine for HB vaccine non-responders.

HBV with precore and basal core promoter mutations exhibits a high replication phenotype and causes ER stress-mediated cell death in humanized liver chimeric mice

BACKGROUND AND AIMS

Mutations within the precore (PC) and basal core promoter (BCP) regions of the HBV genome are associated with fulminant hepatitis and HBV reactivation. These mutations may enhance viral replication, but little is known about whether they directly induce damage to the liver. We investigated mechanisms of direct cytopathic effects induced by the infection with PC/BCP mutants in the absence of immune response in vitro and in vivo .

APPROACH AND RESULTS

Mice with humanized livers and hepatocytes derived from humanized mice were infected with either wild-type or mutant-type PC/BCP HBV, and the HBV replication and human hepatocyte damage were evaluated. HBV proliferated vigorously in mice with PC/BCP-mutant infection, and the severe loss of human hepatocytes with a slight human ALT elevation subsequently occurred only in PC/BCP mutant mice. In PC/BCP mutant infection, the accumulation of HBsAg in humanized livers colocalized with the endoplasmic reticulum, leading to apoptosis through unfolded protein response in HBV-infected hepatocytes. RNA-sequencing revealed the molecular characteristics of the phenotype of PC/BCP mutant infection in a humanized mouse model. Reduced ALT elevation and higher HBV DNA levels in this model are consistent with characteristics of HBV reactivation, indicating that the hepatocyte damage in this model might mimic HBV reactivation followed by hepatocyte damage under immunosuppressive conditions.

CONCLUSION

PC and BCP mutations were associated with enhanced viral replication and cell death induced by ER stress using HBV infection models. These mutations might be associated with liver damage in patients with fulminant hepatitis or HBV reactivation.

Application of spatial transcriptomics analysis using the Visium system for the mouse nasal cavity after intranasal vaccination

Intranasal vaccines that elicit mucosal immunity are deemed effective against respiratory tract infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but their ability to induce humoral immunity characterized by immunoglobulin A (IgA) and IgG production is low. It has been reported that vaccination with a mixture of a viscous base carboxyvinyl polymer (CVP) and viral antigens induced robust systemic and mucosal immune responses. In this study, we analyzed the behavior of immunocompetent cells in the nasal cavity over time by spatial transcriptome profiling induced immediately after antigen vaccination using CVP. We established a method for performing spatial transcriptomics using the Visium system in the mouse nasal cavity and analyzed gene expression profiles within the nasal cavity after intranasal vaccination. Glycoprotein 2 (Gp2)-, SRY-box transcription factor 8 (Sox8)-, or Spi-B transcription factor (Spib)-expressing cells were increased in the nasal passage (NP) region at 3-6 hr after SARS-CoV-2 spike protein and CVP (S-CVP) vaccination. The results suggested that microfold (M) cells are activated within a short period of time (3-6 hr). Subsequent cluster analysis of cells in the nasal cavity showed an increase in Cluster 9 at 3-6 hr after intranasal vaccination with the S-CVP. We found that Il6 in Cluster 9 had the highest log2 fold values within the NP at 3-6 hr. A search for gene expression patterns similar to that of Il6 revealed that the log2 fold values of Edn2, Ccl20, and Hk2 also increased in the nasal cavity after 3-6 hr. The results showed that the early response of immune cells occurred immediately after intranasal vaccination. In this study, we identified changes in gene expression that contribute to the activation of M cells and immunocompetent cells after intranasal vaccination of mice with antigen-CVP using a time-series analysis of spatial transcriptomics data. The results facilitated the identification of the cell types that are activated during the initial induction of nasal mucosal immunity.

Toll-like Receptor Response to Human Immunodeficiency Virus Type 1 or Co-Infection with Hepatitis B or C Virus: An Overview

Toll-like receptors (TLRs) are evolutionarily conserved pattern recognition receptors that play important roles in the early detection of pathogen-associated molecular patterns and shaping innate and adaptive immune responses, which may influence the consequences of infection. Similarly to other viral infections, human immunodeficiency virus type 1 (HIV-1) also modulates the host TLR response; therefore, a proper understanding of the response induced by human HIV-1 or co-infection with hepatitis B virus (HBV) or hepatitis C virus (HCV), due to the common mode of transmission of these viruses, is essential for understanding HIV-1 pathogenesis during mono- or co-infection with HBV or HCV, as well as for HIV-1 cure strategies. In this review, we discuss the host TLR response during HIV-1 infection and the innate immune evasion mechanisms adopted by HIV-1 for infection establishment. We also examine changes in the host TLR response during HIV-1 co-infection with HBV or HCV; however, this type of study is extremely scarce. Moreover, we discuss studies investigating TLR agonists as latency-reverting agents and immune stimulators towards new strategies for curing HIV. This understanding will help develop a new strategy for curing HIV-1 mono-infection or co-infection with HBV or HCV.

CSNK2B modulates IRF1 binding to functional DNA elements and promotes basal and agonist-induced antiviral signaling

Interferon regulatory factor 1 (IRF1) is a critical component of cell-intrinsic innate immunity that regulates both constitutive and induced antiviral defenses. Due to its short half-life, IRF1 function is generally considered to be regulated by its synthesis. However, how IRF1 activity is controlled post-translationally has remained poorly characterized. Here, we employed a proteomics approach to identify proteins interacting with IRF1, and found that CSNK2B, a regulatory subunit of casein kinase 2, interacts directly with IRF1 and constitutively modulates its transcriptional activity. Genome-wide CUT&RUN analysis of IRF1 binding loci revealed that CSNK2B acts generally to enhance the binding of IRF1 to chromatin, thereby enhancing transcription of key antiviral genes, such as PLAAT4 (also known as RARRES3/RIG1/TIG3). On the other hand, depleting CSNK2B triggered abnormal accumulation of IRF1 at AFAP1 loci, thereby down-regulating transcription of AFAP1, revealing contrary effects of CSNK2B on IRF1 binding at different loci. AFAP1 encodes an actin crosslinking factor that mediates Src activation. Importantly, CSNK2B was also found to mediate phosphorylation-dependent activation of AFAP1-Src signaling and exert suppressive effects against flaviviruses, including dengue virus. These findings reveal a previously unappreciated mode of IRF1 regulation and identify important effector genes mediating multiple cellular functions governed by CSNK2B and IRF1.

Intranasal therapeutic vaccine containing HBsAg and HBcAg for patients with chronic hepatitis B; 18 months follow-up results of phase IIa clinical study

AIMS

HBsAg loss with anti-HBs acquisition is considered a functional cure and ideal treatment goal for patients with CHB. Our group have reported the efficacy of therapeutic vaccine with HBsAg and HBcAg (NASVAC) by intranasal and subcutaneous injection. In this study, we investigated the safety and efficacy of newly developed CVP-NASVAC, which contained NASVAC with mucoadhesive carboxyl vinyl polymer (CVP) in the dedicated device.

METHODS

A single dose, open-label, phase IIa clinical trial of CVP-NASVAC was conducted. Patients with CHB treated with nucleoside/nucleotide analogs (NAs) and HBV carriers not undergoing anti-HBV treatment were enrolled. CVP-NASVAC was injected through the nose for, in total, 10 times. Participants were followed-up for 18 months, and their HBsAg reduction and anti-HBs induction assessed as endpoints.

RESULTS

Among the patients with CHB treated with NAs (n = 27) and HBV carriers without NAs (n = 36), 74.1% and 75.0% exhibited reductions in their baseline HBsAg, and the mean reductions were -0.1454 log₁₀  IU/ml (p < 0.05) and -0.2677 log₁₀  IU/ml (p < 0.05), respectively. Anti-HBs antibody was detected in 40.7% and 58.3% of patients treated with and without NAs, respectively. Six of 71 (9.5%) patients were functionally cured after the CVP-NASVAC treatment.

CONCLUSIONS

Anti-HBs induction and HBsAg reduction was observed after CVP-NASVAC treatment in some patients with CHB. The CVP-NASVAC is a safe treatment, which might expect to achieve functional cure for patients with CHB.

Reduced antibody response to SARS-CoV-2 in COVID-19 patients with newly diagnosed diabetes: a retrospective observational study

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has dramatically impacted global health, and patients with type 2 diabetes have been identified as a high-risk group for COVID-19 infection and the development of severe disease. In response, this study aimed to evaluate whether patients with type 2 diabetes infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could develop antibody responses in the same manner as patients without diabetes, and whether there is a difference in antibody response to SARS-CoV-2 between patients with diabetes diagnosed prior to hospitalization, and those with newly diagnosed diabetes.

METHODS

SARS-CoV-2-specific immunoglobulin G (IgG) levels were quantified using two iFlash 3000 Chemiluminescence Immunoassay analyzer kits (Shenzhen YHLO Biotech Co., Ltd.) to detect IgG antibodies specific for nucleocapsid protein (IgG-N), and specific for the S1 subunit of the spike protein (IgG-S1). In 124 hospitalized patients with COVID-19, 40 patients with type 2 diabetes were matched to 40 patients without diabetes using propensity score matching (PSM).

RESULTS

There was no difference in IgG-N and IgG-S1 levels between the patients with diabetes and those without. Of patients with diabetes, 31 patients had known diabetes and nine patients had newly diagnosed diabetes. The median levels of IgG-N at 7-13 days in patients with newly diagnosed diabetes were significantly lower than those in patients with known diabetes (IgG-N; 10.9 vs. 31.0 AU/mL, p = 0.031, IgG-S1; 7.5 vs. 24.4 AU/mL, p = 0.023).

CONCLUSIONS

Even after adjusting for covariates using PSM, COVID-19 patients with type 2 diabetes had comparable antibody responses to patients without diabetes. Patients with newly diagnosed diabetes had lower IgG-N and IgG-S1 production in the second week of the disease compared with those with previously known diabetes.

Increasing Dengue Burden and Severe Dengue Risk in Bangladesh: An Overview

Dengue is a prevalent and rapidly spreading mosquito-borne viral disease affecting humans. The geographic range of dengue is expanding, and much like in many other tropical regions of the world, dengue has become a major public health issue in Bangladesh. Until a large epidemic dengue outbreak in 2000, sporadic outbreaks have occurred in Bangladesh since 1964. After 2000, varying intensities of dengue activity were observed each year until 2018. However, in 2019, Bangladesh experienced the largest dengue epidemic in its history, with 101,354 dengue cases and 164 dengue-related deaths. Notably, this outbreak occurred in many regions that were previously considered free of the disease. As of 10 December 2022, a total of 60,078 dengue cases and 266 dengue-related deaths were reported in Bangladesh, with the 2022 outbreak being the second largest since 2000. There is an increased genetic diversity of the dengue virus (DENV) in Bangladesh and all four DENV serotypes are prevalent and co-circulating, which increases the risk for severe dengue owing to the antibody-dependent enhancement effect. Vector control remains the mainstay of dengue outbreak prevention; however, the vector control programs adopted in Bangladesh seem inadequate, requiring improved vector control strategies. In this review, we provide an overview of the epidemiology of DENV infection and the risks for a severe dengue outbreak in Bangladesh. Additionally, we discuss different dengue vector control strategies, from which the most suitable and effective measures can be applied in the context of Bangladesh for tackling future dengue epidemics.

B cell receptor repertoire analysis from autopsy samples of COVID-19 patients

Neutralizing antibodies against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are being developed world over. We investigated the possibility of producing artificial antibodies from the formalin fixation and paraffin-embedding (FFPE) lung lobes of a patient who died by coronavirus disease 2019 (COVID-19). The B-cell receptors repertoire in the lung tissue where SARS-CoV-2 was detected were considered to have highly sensitive virus-neutralizing activity, and artificial antibodies were produced by combining the most frequently detected heavy and light chains. Some neutralizing effects against the SARS-CoV-2 were observed, and mixing two different artificial antibodies had a higher tendency to suppress the virus. The neutralizing effects were similar to the immunoglobulin G obtained from healthy donors who had received a COVID-19 mRNA vaccine. Therefore, the use of FFPE lung tissue, which preserves the condition of direct virus sensitization, to generate artificial antibodies may be useful against future unknown infectious diseases.

An attenuated vaccinia vaccine encoding the severe acute respiratory syndrome coronavirus-2 spike protein elicits broad and durable immune responses, and protects cynomolgus macaques and human angiotensin-converting enzyme 2 transgenic mice from severe acute respiratory syndrome coronavirus-2 and its variants

As long as the coronavirus disease-2019 (COVID-19) pandemic continues, new variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) with altered antigenicity will emerge. The development of vaccines that elicit robust, broad, and durable protection against SARS-CoV-2 variants is urgently required. We have developed a vaccine consisting of the attenuated vaccinia virus Dairen-I (DIs) strain platform carrying the SARS-CoV-2  S gene (rDIs-S). rDIs-S induced neutralizing antibody and T-lymphocyte responses in cynomolgus macaques and human angiotensin-converting enzyme 2 (hACE2) transgenic mice, and the mouse model showed broad protection against SARS-CoV-2 isolates ranging from the early-pandemic strain (WK-521) to the recent Omicron BA.1 variant (TY38-873). Using a tandem mass tag (TMT)-based quantitative proteomic analysis of lung homogenates from hACE2 transgenic mice, we found that, among mice subjected to challenge infection with WK-521, vaccination with rDIs-S prevented protein expression related to the severe pathogenic effects of SARS-CoV-2 infection (tissue destruction, inflammation, coagulation, fibrosis, and angiogenesis) and restored protein expression related to immune responses (antigen presentation and cellular response to stress). Furthermore, long-term studies in mice showed that vaccination with rDIs-S maintains S protein-specific antibody titers for at least 6 months after a first vaccination. Thus, rDIs-S appears to provide broad and durable protective immunity against SARS-CoV-2, including current variants such as Omicron BA.1 and possibly future variants.

Epidemiology and Risk Factors for Acute Viral Hepatitis in Bangladesh: An Overview

Viral infections by hepatotropic viruses can cause both acute and chronic infections in the liver, resulting in morbidity and mortality in humans. Hepatotropic viruses, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV), are the major pathogens that cause acute and chronic infections in humans. Although all of these viruses can cause acute hepatitis in humans, HAV and HEV are the predominant causative agents in Bangladesh, where the occurrence is sporadic throughout the year. In this review, we provide an overview of the epidemiology of hepatotropic viruses that are responsible for acute hepatitis in Bangladesh. Additionally, we focus on the transmission modes of these viruses and the control and prevention of infections.

Attenuated humoral response against SARS-CoV-2 mRNA vaccination in allogeneic stem cell transplantation recipients

Antibody persistence several months after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination in allogeneic stem cell transplantation recipients remains largely unknown. We sequentially evaluated the humoral response to two doses of mRNA vaccines in 128 adult recipients and identified the risk factors involved in a poor response. The median interval between stem cell transplantation and vaccination was 2.7 years. The SARS-CoV-2 S1 Ab became positive after the second vaccination dose in 87.6% of the recipients, and the median titer was 1235.4 arbitrary units (AU)/ml. In patients on corticosteroid treatment, the corticosteroid dose inversely correlated with Ab titer. Multivariate analysis identified risk factors for poor peak response such as an interval from stem cell transplantation ≤1 year, history of clinically significant CMV infection, and use of >5 mg/day prednisolone at vaccination. Six months after vaccination, the median titer decreased to 185.15 AU/ml, and use of >5 mg/day prednisolone at vaccination was significantly associated with a poor response. These results indicate that early vaccination after stem cell transplantation (<12 months) and CMV infection are risk factors for poor peak response, while steroid use is important for a peak as well as a persistent response. In conclusion, although humoral response is observed in many stem cell transplantation recipients after two doses of vaccination, Ab titers diminish with time, and factors associated with persistence and a peak immunity should be considered separately.

Inhibition of CBP/β-catenin signaling ameliorated fibrosis in cholestatic liver disease

Chronic cholestatic liver diseases are characterized by injury of the bile ducts and hepatocytes caused by accumulated bile acids (BAs) and inflammation. Wnt/β-catenin signaling is implicated in organ fibrosis; however, its role in cholestatic liver fibrosis remains unclear. Therefore, we explored the effect of a selective cAMP response element-binding protein-binding protein (CBP)/β-catenin inhibitor, PRI-724, on murine cholestatic liver fibrosis. PRI-724 suppressed liver fibrosis induced by multidrug resistance protein 2 knockout (KO), bile duct ligation, or a 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) diet; it also suppressed BA synthesis and macrophage infiltration. The expression of early growth response-1 (Egr-1), which plays a key role in BA synthesis, was increased in the hepatocytes of patients with cholestatic liver disease. PRI-724 inhibited Egr-1 expression induced by cholestasis, and adenoviral shEgr-1-mediated Egr-1 knockdown suppressed BA synthesis and fibrosis in DDC diet-fed mice, suggesting that PRI-724 exerts its effects, at least in part, by suppressing Egr-1 expression in hepatocytes. Hepatocyte-specific CBP KO in mice suppressed BA synthesis, liver injury, and fibrosis, whereas hepatocyte-specific KO of P300, a CBP homolog, exacerbated DDC-induced fibrosis. Intrahepatic Egr-1 expression was also decreased in hepatocyte-specific CBP-KO mice and increased in P300-KO mice, indicating that Egr-1 is located downstream of CBP/β-catenin signaling. Conclusion: PRI-724 inhibits cholestatic liver injury and fibrosis by inhibiting BA synthesis in hepatocytes. These results highlight the therapeutic effect of CBP/β-catenin inhibition in cholestatic liver diseases.

In vivo Delivery Tools for Clustered Regularly Interspaced Short Palindromic Repeat/Associated Protein 9-Mediated Inhibition of Hepatitis B Virus Infection: An Update

Chronic hepatitis B virus (HBV) infection remains a major global health problem despite the availability of an effective prophylactic HBV vaccine. Current antiviral therapies are unable to fully cure chronic hepatitis B (CHB) because of the persistent nature of covalently closed circular DNA (cccDNA), a replicative template for HBV, which necessitates the development of alternative therapeutic approaches. The CRISPR/Cas system, a newly emerging genome editing tool, holds great promise for genome editing and gene therapy. Several in vitro and/or in vivo studies have demonstrated the effectiveness of HBV-specific clustered regularly interspaced short palindromic repeat (CRISPR)/associated protein 9 (CRISPR/Cas9) systems in cleaving HBV DNA and cccDNA. Although recent advances in CRISPR/Cas technology enhance its prospects for clinical application against HBV infection, in vivo delivery of the CRISPR/Cas9 system at targets sites remains a major challenge that needs to be resolved before its clinical application in gene therapy for CHB. In the present review, we discuss CRISPR/Cas9 delivery tools for targeting HBV infection, with a focus on the development of adeno-associated virus vectors and lipid nanoparticle (LNP)-based CRISPR/Cas ribonucleoprotein (RNP) delivery to treat CHB. In addition, we discuss the importance of delivery tools in the enhancement of the antiviral efficacy of CRISPR/Cas9 against HBV infection.

Reverse vaccinology-based prediction of a multi-epitope SARS-CoV-2 vaccine and its tailoring to new coronavirus variants

The genome feature of SARS-CoV-2 leads the virus to mutate and creates new variants of concern. Tackling viral mutations is also an important challenge for the development of a new vaccine. Accordingly, in the present study, we undertook to identify B- and T-cell epitopes with immunogenic potential for eliciting responses to SARS-CoV-2, using computational approaches and its tailoring to coronavirus variants. A total of 47 novel epitopes were identified as immunogenic triggering immune responses and no toxic after investigation with in silico tools. Furthermore, we found these peptide vaccine candidates showed a significant binding affinity for MHC I and MHC II alleles in molecular docking investigations. We consider them to be promising targets for developing peptide-based vaccines against SARS-CoV-2. Subsequently, we designed two efficient multi-epitopes vaccines against the SARS-CoV-2, the first one based on potent MHC class I and class II T-cell epitopes of S (FPNITNLCPF-NYNYLYRLFR-MFVFLVLLPLVSSQC), M (MWLSYFIASF-GLMWLSYFIASFRLF), E (LTALRLCAY-LLFLAFVVFLLVTLA), and N (SPRWYFYYL-AQFAPSASAFFGMSR). The second candidate is the result of the tailoring of the first designed vaccine according to three classes of SARS-CoV-2 variants. Molecular docking showed that the protein-protein binding interactions between the vaccines construct and TLR2-TLR4 immune receptors are stable complexes. These findings confirmed that the final multi-epitope vaccine could be easily adapted to new viral variants. Our study offers a shortlist of promising epitopes that can accelerate the development of an effective and safe vaccine against the virus and its adaptation to new variants.Communicated by Ramaswamy H. Sarma.

Nanobodies: an unexplored opportunity to combat COVID-19

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by severe acute respiratory coronavirus 2 (SARS-CoV-2). This virus is capable of human-to-human transmission, and is spreading rapidly round the globe, with markedly high fatality rates. Unfortunately, there are neither vaccines nor specific therapies available to combat it, and the developments of such approaches depend on pursuing multiple avenues in biomedical science. Accordingly, in this paper we highlight one such avenue-nanobodies-for potential utility in therapeutic and diagnostic interventions to combat COVID-19.Communicated by Ramaswamy H. Sarma.

Infection with the SARS-CoV-2 B.1.351 variant is lethal in aged BALB/c mice

Models of animals that are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can usefully evaluate the efficacy of vaccines and therapeutics. In this study, we demonstrate that infection with the SARS-CoV-2 B.1.351 variant (TY8-612 strain) induces bodyweight loss and inflammatory cytokine/chemokine production in wild-type laboratory mice (BALB/c and C57BL/6 J mice). Furthermore, compared to their counterparts, BALB/c mice had a higher viral load in their lungs and worse symptoms. Importantly, infecting aged BALB/c mice (older than 6 months) with the TY8-612 strain elicited a massive and sustained production of multiple pro-inflammatory cytokines/chemokines and led to universal mortality. These results indicated that the SARS-CoV-2 B.1.351 variant-infected mice exhibited symptoms ranging from mild to fatal depending on their strain and age. Our data provide insights into the pathogenesis of SARS-CoV-2 and may be useful in developing prophylactics and therapeutics.

Serologic Survey of IgG Against SARS-CoV-2 Among Hospital Visitors Without a History of SARS-CoV-2 Infection in Tokyo, 2020-2021

BACKGROUND

Tokyo, the capital of Japan, is a densely populated city of >13 million people, so the population is at high risk of epidemic severe acute respiratory coronavirus 2 (SARS-CoV-2) infection. A serologic survey of anti-SARS-CoV-2 IgG would provide valuable data for assessing the city's SARS-CoV-2 infection status. Therefore, this cross-sectional study estimated the anti-SARS-CoV-2 IgG seroprevalence in Tokyo.

METHODS

Leftover serum of 23,234 hospital visitors was tested for antibodies against SARS-CoV-2 using an iFlash 3000 chemiluminescence immunoassay analyzer (Shenzhen YHLO Biotech, Shenzhen, China) with an iFlash-SARS-CoV-2 IgG kit (YHLO) and iFlash-SARS-CoV-2 IgG-S1 kit (YHLO). Serum samples with a positive result (≥10 AU/mL) in either of these assays were considered seropositive for anti-SARS-CoV-2 IgG. Participants were randomly selected from patients visiting 14 Tokyo hospitals between September 1, 2020 and March 31, 2021. No participants were diagnosed with coronavirus disease 2019 (COVID-19), and none exhibited COVID-19-related symptoms at the time of blood collection.

RESULTS

The overall anti-SARS-CoV-2 IgG seroprevalence among all participants was 1.83% (95% confidence interval [CI], 1.66-2.01%). The seroprevalence in March 2021, the most recent month of this study, was 2.70% (95% CI, 2.16-3.34%). After adjusting for population age, sex, and region, the estimated seroprevalence in Tokyo was 3.40%, indicating that 470,778 individuals had a history of SARS-CoV-2 infection.

CONCLUSIONS

The estimated number of individuals in Tokyo with a history of SARS-CoV-2 infection was 3.9-fold higher than the number of confirmed cases. Our study enhances understanding of the SARS-CoV-2 epidemic in Tokyo.

Hemodialysis patients with coronavirus disease 2019: reduced antibody response

BACKGROUND

Because patients on maintenance hemodialysis (HD) have an impaired immune response to pathogens, they are at higher risk of severe coronavirus disease 2019 (COVID-19). However, data on antibody production among HD patients with COVID-19 is scarce. Thus, we performed a retrospective cohort study evaluating severe acute respiratory syndrome coronavirus two antibody (SARS-CoV-2) production within 1 month after COVID-19 onset in hospitalized patients on HD.

METHODS

SARS-CoV-2-specific immunoglobulin (Ig) G levels were quantified using an iFlash 3000 Chemiluminescence Immunoassay analyzer (Shenzhen YHLO Biotech Co., Ltd.) to detect IgG antibodies specific for the S1 subunit of the spike protein (IgG-S1). Propensity score matching was used to balance covariate distribution in HD and non-HD patients. From April 2020 to February 2021, antibody testing was performed on 161 hospitalized patients with symptomatic COVID-19. Of them, 34 HD patients were matched to 68 non-HD patients.

RESULTS

After propensity score matching, the median levels of IgG-S1 in the HD patients at 7-13 days after symptom onset were significantly lower than in non-HD patients, especially in those with severe disease. Among all patients, those with severe disease produced lower levels of IgG-S1 at 7-13 days compared with non-severe patients.

CONCLUSION

COVID-19 patients with severe disease, especially those undergoing HD, had lower IgG-S1 production in the second week of the disease. Thus, the increased risk of severe COVID-19 in HD patients may be, in part, due to a slow and reduced antibody response.

Longer Poly(U) Stretches in the 3'UTR Are Essential for Replication of the Hepatitis C Virus Genotype 4a Clone in in vitro and in vivo

The 3′ untranslated region (UTR) of the hepatitis C virus (HCV) genome plays a significant role in replication including the poly(U) tract (You and Rice, 2008). Here we established an HCV clone that is infectious in vitro and in vivo, from an Egyptian patient with chronic HCV infection and hepatocellular carcinoma (HCC). First, we inoculated the patient plasma into a humanized chimeric mouse and passaged. We observed HCV genotype 4a propagation in the chimeric mouse sera at 1.7 × 10⁷ copies/mL after 6 weeks. Next, we cloned the entire HCV sequence from the HCV-infected chimeric mouse sera using RT-PCR, and 5′ and 3′ RACE methodologies. We obtained first a shorter clone (HCV-G4 KM short, GenBank: AB795432.1), which contained 9,545 nucleotides with 341 nucleotides of the 5′UTR and 177 nucleotides of the 3′UTR, and this was frequently obtained for unknown reasons. We also obtained a longer clone by dividing the HCV genome into three fragments and the poly (U) sequences. We obtained a longer 3′UTR sequence than that of the HCV-G4 KM short clone, which contained 9,617 nucleotides. This longer clone possessed a 3′-UTR of 249 nucleotides (HCV-G4 KM long, GenBank: AB795432.2), because of a 71-nucleotide longer poly (U) stretch. The HCV-G4-KM long clone, but not the HCV-G4-KM short clone, could establish infection in human hepatoma HuH-7 cells. HCV RNAs carrying a nanoluciferase (NL) reporter were also constructed and higher replication activity was observed with G4-KM long-NL in vitro. Next, both short and long RNAs were intra-hepatically injected into humanized chimeric mice. Viral propagation was only observed for the chimeric mouse injected with the HCV-G4 KM long RNA in the sera after 21 days (1.64 × 10⁶ copies/mL) and continued until 10 weeks post inoculation (wpi; 1.45–4.74 × 10⁷ copies/mL). Moreover, sequencing of the HCV genome in mouse sera at 6 wpi revealed the sequence of the HCV-G4-KM long clone. Thus, the in vitro and in vivo results of this study indicate that the sequence of the HCV-G4-KM long RNA is that of an infectious clone.

An Overview of Recent Insights into the Response of TLR to SARS-CoV-2 Infection and the Potential of TLR Agonists as SARS-CoV-2 Vaccine Adjuvants

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to coronavirus disease (COVID-19), a global health pandemic causing millions of deaths worldwide. However, the immunopathogenesis of COVID-19, particularly the interaction between SARS-CoV-2 and host innate immunity, remains unclear. The innate immune system acts as the first line of host defense, which is critical for the initial detection of invading pathogens and the activation and shaping of adaptive immunity. Toll-like receptors (TLRs) are key sensors of innate immunity that recognize pathogen-associated molecular patterns and activate downstream signaling for pro-inflammatory cytokine and chemokine production. However, TLRs may also act as a double-edged sword, and dysregulated TLR responses may enhance immune-mediated pathology, instead of providing protection. Therefore, a proper understanding of the interaction between TLRs and SARS-CoV-2 is of great importance for devising therapeutic and preventive strategies. The use of TLR agonists as vaccine adjuvants for human disease is a promising approach that could be applied in the investigation of COVID-19 vaccines. In this review, we discuss the recent progress in our understanding of host innate immune responses in SARS-CoV-2 infection, with particular focus on TLR response. In addition, we discuss the use of TLR agonists as vaccine adjuvants in enhancing the efficacy of COVID-19 vaccine.

Estimating Drug Efficacy with a Diet-Induced NASH Model in Chimeric Mice with Humanized Livers

Nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is the most common liver disorder in developed countries. Although many new therapeutics for NASH are present in the drug development pipeline, there are still no approved drugs. One of the reasons that makes NASH drug development challenging is the lack of appropriate animal NASH models that resolve issues arising from inter-species differences between humans and rodents. In the present study, we developed a choline-deficient, L-amino-acid-defined, high-fat-diet (CDAHFD)-induced human NASH model using human liver chimeric mice. We demonstrated human hepatocyte injury by an elevation of plasma human alanine aminotransferase 1 in mice fed CDAHFD. Histological analysis showed that CDAHFD feeding induced similar histological changes to human NASH patients, including ballooning, inflammation, apoptosis, regeneration of human hepatocytes, and pericellular and perisinusoidal fibrosis. The chimeric mice fed CDAHFD were treated with a peroxisome-proliferator-activated receptor α/δ agonist, Elafibranor. Elafibranor ameliorated steatosis, ballooning of hepatocytes, and preserved fibrosis progression. We developed a novel humanized NASH model that can elucidate pathophysiological mechanisms and predict therapeutic efficacy in human NASH. This model will be useful in exploring new drugs and biomarkers in the early stages of human NASH.

Blocking neddylation elicits antiviral effect against hepatitis B virus replication

BACKGROUND

Hepatitis B Virus (HBV) is the most common cause of chronic liver disease worldwide. The mechanisms that regulate HBV viral replication remain poorly defined. Here, we show that blocking of the neddylation elicits antiviral effect against HBV replication, indicating that NEDD8 supports viral production.

METHODS AND RESULTS

To explore role of neddylation, HBV-replicating HepG2.2.15.7 cells and HBV-infected HepG2-hNTCP-30 cells were treated with siNEDD8 and MLN4924, a potent and selective NEDD8-activating enzyme inhibitor. Cell viability, intracellular and extracellular HBV DNA, covalently closed circular DNA (cccDNA), HBsAg, HBeAg, and HBcrAg were measured to assess the consequences of the various treatments on viral replication. Our data showed that HBV infection increased NEDD8 expression in human liver cell lines. Symmetrically, NEDD8 knockdown by siRNA or MLN4924 treatments decreased HBV replication in HepG2.2.15.7 and HepG2-hNTCP-30 cells. Notably, HBsAg, and HBeAg secretions were strongly suppressed in the culture supernatants, but not the HBcrAg. These results indicate that the suppression of NEDD8 decreases HBV replication. However, cccDNA steady level confirms once again its persistence and longevity in chronic infection.

CONCLUSION

The manipulation of the neddylation pathway can thus provide new tools interfering with HBV persistence as well as novel therapeutic strategies against chronic hepatitis B.

Toll-Like Receptor Response to Hepatitis B Virus Infection and Potential of TLR Agonists as Immunomodulators for Treating Chronic Hepatitis B: An Overview

Chronic hepatitis B virus (HBV) infection remains a major global health problem. The immunopathology of the disease, especially the interplay between HBV and host innate immunity, is poorly understood. Moreover, inconsistent literature on HBV and host innate immunity has led to controversies. However, recently, there has been an increase in the number of studies that have highlighted the link between innate immune responses, including Toll-like receptors (TLRs), and chronic HBV infection. TLRs are the key sensing molecules that detect pathogen-associated molecular patterns and regulate the induction of pro- and anti-inflammatory cytokines, thereby shaping the adaptive immunity. The suppression of TLR response has been reported in patients with chronic hepatitis B (CHB), as well as in other models, including tree shrews, suggesting an association of TLR response in HBV chronicity. Additionally, TLR agonists have been reported to improve the host innate immune response against HBV infection, highlighting the potential of these agonists as immunomodulators for enhancing CHB treatment. In this study, we discuss the current understanding of host innate immune responses during HBV infection, particularly focusing on the TLR response and TLR agonists as immunomodulators.

Ageing and chronic disease-related changes in the morphometric characteristics of ovarian follicles in cynomolgus monkeys (Macaca fascicularis)

STUDY QUESTION

How is the localisation of ovarian follicles affected by ageing and chronic diseases?

SUMMARY ANSWER

Ovarian follicles shift deeper towards the medulla, due to thickening of the tunica albuginea (TA), with ageing and some major common chronic diseases.

WHAT IS KNOWN ALREADY

The ovary undergoes morphological and functional changes with ageing. The follicular pool follows these changes with alterations in the amount and distribution of residual follicles. Diseases causing a chronic inflammatory process are associated with morphological changes and impaired ovarian function.

STUDY DESIGN, SIZE, DURATION

We conducted a cross-sectional study, examining 90 ovaries from 90 female monkeys. The samples were collected from April 2018 to March 2019 at Tsukuba Primate Research Center in National Institutes of Biomedical Innovation, Health and Nutrition, Japan.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovarian samples were obtained from cynomolgus monkeys that died from natural causes or were euthanised. Ovarian sections were stained with haematoxylin and eosin (H&E) for histological analyses. In ovarian sections from 64 female macaques aged 0-25 years, a total of 13 743 follicles at different developmental stages (primordial, intermediary, primary, early secondary and late secondary) were assessed to determine the depth of each follicle from the outer surface of the ovarian cortex to the far end of the follicle, by using a digital imaging software. TA thickness was measured as sum of basal membrane and tunica collagen layer for each ovary under H&E staining. To explore the possibility of age-related trends in ovarian morphometric characteristics, samples were divided into four different age groups (0-3 years (pre-menarche), 4-9 years, 10-14 years and 15-20 years). To evaluate the effect of common chronic diseases on ovarian morphometric characteristics, macaques with diabetes mellitus (DM) (n = 10), endometriosis (n = 8) or inflammatory bowel disease (IBD) (n = 8) were compared to age-matched controls without chronic diseases.

MAIN RESULTS AND THE ROLE OF CHANCE

Ovarian morphometric analysis revealed that the relative location of follicles became deeper in all age groups according to development of follicles (P < 0.05). Total follicle distance from the ovarian surface was increased with ageing (P < 0.05). In a sub-analysis according to developmental stage, only primordial and intermediary follicles were localised deeper with increasing age (P < 0.05). TA thickness was also increased with ageing (P < 0.05). The localisation of the total number of follicles became deeper in ovaries from monkeys with DM, endometriosis or IBD as compared to the control group (P < 0.05). With DM, analysis of follicles distance at almost each developmental stage was significantly deeper compared to controls (P < 0.05) with the exception of early secondary follicles. With endometriosis, follicles at primary and early and late secondary stages were significantly deeper compared to controls (P < 0.05). Also with IBD, follicles at primary and early and late secondary follicles were significantly deeper compared to controls (P < 0.001). The TA was thicker with DM and endometriosis compared to controls (P < 0.05), but not with IBD (P = 0.16).

LARGE SCALE DATA

NA.

LIMITATIONS, REASONS FOR CAUTION

Two-dimensional histology was used to assess follicle localisation. The possibility of minimal variations between the measured distance to the actual distance in a spherical structure cannot be excluded. Additionally, the severity of disease was not assessed.

WIDER IMPLICATIONS OF THE FINDINGS

This study is the first step towards enhancing our understanding of how ageing and chronic diseases affect the relative localisation of dormant and developing follicles. These observations, combined with possible future human studies, may have managerial implications in the field of fertility preservation and other conditions involving ovarian tissue cryopreservation.

STUDY FUNDING/COMPETING INTEREST(S)

The present work was supported by the Grant-in-Aid for Scientific Research B (19H03801) (to K.K.), Challenging Exploratory Research (18K19624), Japan Agency for Medical Research and Development, Mochida Memorial Foundation for Medical and Pharmaceutical Research, Takeda Science Foundation and Naito Foundation (to K.K.). All authors have no conflicts of interest directly relevant to the content of this article.

Recent Insights Into the Molecular Mechanism of Toll-Like Receptor Response to Dengue Virus Infection

Dengue is the most prevalent and rapidly spreading mosquito-borne viral disease caused by dengue virus (DENV). Recently, DENV has been affecting humans within an expanding geographic range due to the warming of the earth. Innate immune responses play a significant role in antiviral defense, and Toll-like receptors (TLRs) are key regulators of innate immunity. Therefore, a detailed understanding of TLR and DENV interactions is important for devising therapeutic and preventive strategies. Several studies have indicated the ability of DENV to modulate the TLR signaling pathway and host immune response. Vaccination is considered one of the most successful medical interventions for preventing viral infections. However, only a partially protective dengue vaccine, the first licensed dengue vaccine CYD-TDV, is available in some dengue-endemic countries to protect against DENV infection. Therefore, the development of a fully protective, durable, and safe DENV vaccine is a priority for global health. Here, we demonstrate the progress made in our understanding of the host response to DENV infection, with a particular focus on TLR response and how DENV avoids the response toward establishing infection. We also discuss dengue vaccine candidates in late-stage development and the issues that must be overcome to enable their success.

FADS2-dependent fatty acid desaturation dictates cellular sensitivity to ferroptosis and permissiveness for hepatitis C virus replication

The metabolic oxidative degradation of cellular lipids severely restricts replication of hepatitis C virus (HCV), a leading cause of chronic liver disease, but little is known about the factors regulating this process in infected cells. Here we show that HCV is restricted by an iron-dependent mechanism resembling the one triggering ferroptosis, an iron-dependent form of non-apoptotic cell death, and mediated by the non-canonical desaturation of oleate to Mead acid and other highly unsaturated fatty acids by fatty acid desaturase 2 (FADS2). Genetic depletion and ectopic expression experiments show FADS2 is a key determinant of cellular sensitivity to ferroptosis. Inhibiting FADS2 markedly enhances HCV replication, whereas the ferroptosis-inducing compound erastin alters conformation of the HCV replicase and sensitizes it to direct-acting antiviral agents targeting the viral protease. Our results identify FADS2 as a rate-limiting factor in ferroptosis, and suggest the possibility of pharmacologically manipulating the ferroptosis pathway to attenuate viral replication.

Tree Shrew as an Emerging Small Animal Model for Human Viral Infection: A Recent Overview

Viral infection is a global public health threat causing millions of deaths. A suitable small animal model is essential for viral pathogenesis and host response studies that could be used in antiviral and vaccine development. The tree shrew (Tupaia belangeri or Tupaia belangeri chinenesis), a squirrel-like non-primate small mammal in the Tupaiidae family, has been reported to be susceptible to important human viral pathogens, including hepatitis viruses (e.g., HBV, HCV), respiratory viruses (influenza viruses, SARS-CoV-2, human adenovirus B), arboviruses (Zika virus and dengue virus), and other viruses (e.g., herpes simplex virus, etc.). The pathogenesis of these viruses is not fully understood due to the lack of an economically feasible suitable small animal model mimicking natural infection of human diseases. The tree shrew model significantly contributes towards a better understanding of the infection and pathogenesis of these important human pathogens, highlighting its potential to be used as a viable viral infection model of human viruses. Therefore, in this review, we summarize updates regarding human viral infection in the tree shrew model, which highlights the potential of the tree shrew to be utilized for human viral infection and pathogenesis studies.

Macrocyclic peptides exhibit antiviral effects against influenza virus HA and prevent pneumonia in animal models

Most anti-influenza drugs currently used, such as oseltamivir and zanamivir, inhibit the enzymatic activity of neuraminidase. However, neuraminidase inhibitor-resistant viruses have already been identified from various influenza virus isolates. Here, we report the development of a class of macrocyclic peptides that bind the influenza viral envelope protein hemagglutinin, named iHA. Of 28 iHAs examined, iHA-24 and iHA-100 have inhibitory effects on the in vitro replication of a wide range of Group 1 influenza viruses. In particular, iHA-100 bifunctionally inhibits hemagglutinin-mediated adsorption and membrane fusion through binding to the stalk domain of hemagglutinin. Moreover, iHA-100 shows powerful efficacy in inhibiting the growth of highly pathogenic influenza viruses and preventing severe pneumonia at later stages of infection in mouse and non-human primate cynomolgus macaque models. This study shows the potential for developing cyclic peptides that can be produced more efficiently than antibodies and have multiple functions as next-generation, mid-sized biomolecules.

Lipid nanoparticles loaded with ribonucleoprotein-oligonucleotide complexes synthesized using a microfluidic device exhibit robust genome editing and hepatitis B virus inhibition

The clustered regularly interspaced short palindromic repeats (CRISPR)-associated (Cas) system has considerable therapeutic potential for use in treating a wide range of intractable genetic and infectious diseases including hepatitis B virus (HBV) infections. While non-viral delivery technologies for the CRISPR/Cas system are expected to have clinical applications, difficulties associated with the clinically relevant synthesis of formulations and the poor efficiency of delivery severely hinder therapeutic genome editing. We report herein on the production of a lipid nanoparticle (LNP)-based CRISPR/Cas ribonucleoprotein (RNP) delivery nanoplatform synthesized using a clinically relevant mixer-equipped microfluidic device. DNA cleavage activity and the aggregation of Cas enzymes was completely avoided under the optimized synthetic conditions. The optimized formulation, which was identified through 2 steps of design of experiments, exhibited excellent gene disruption (up to 97%) and base substitution (up to 23%) without any apparent cytotoxicity. The addition of negative charges to the RNPs by complexing single-stranded oligonucleotide (ssON) significantly enhanced the delivery of both Cas9 and Cpf1 RNPs. The optimized formulation significantly suppressed both HBV DNA and covalently closed circular DNA (cccDNA) in HBV-infected human liver cells compared to adeno-associated virus type 2 (AAV2). These findings represent a significant contribution to the development of CRISPR/Cas RNP delivery technology and its practical applications in genome editing therapy.

Development of an in vivo delivery system for CRISPR/Cas9-mediated targeting of hepatitis B virus cccDNA

Chronic hepatitis B virus (HBV) infection constitutes a global health issue with limited current therapeutic efficacy owing to the persistence of viral episomal DNA (cccDNA). The CRISPR/Cas9 system, a newly developed, powerful tool for genome editing and potential gene therapy, requires efficient delivery of CRISPR components for successful therapeutic application. Here, we investigated the effects of lentiviral- or adeno-associated virus 2 (AAV2) vector-mediated delivery of 3 guide (g)RNAs/Cas9 selected from 16 gRNAs. These significantly suppressed HBV replication in cells, with WJ11/Cas9 exhibiting highest efficacy and chosen for in vivo study. AAV2/WJ11-Cas9 also significantly inhibited HBV replication and significantly reduced cccDNA in the tested cells. Moreover, AAV2/WJ11-Cas9 enhanced entecavir effects when used in combination, indicative of different modes of action. Notably, in humanized chimeric mice, AAV2/WJ11-Cas9 significantly suppressed HBcAg, HBsAg, and HBV DNA along with cccDNA in the liver tissues without significant cytotoxicity; accordingly, next generation sequencing data showed no significant genomic mutations. To our knowledge, this represents the first evaluation of the CRISPR/Cas9 system using an HBV natural infection mode. Therefore, WJ11/Cas9 delivered by comparatively safer AAV2 vectors may provide a new therapeutic strategy for eliminating HBV infection and serve as an effective platform for curing chronic HBV infection.

Structure-guided discovery approach identifies potential lead compounds targeting Mpro of SARS-CoV-2

The ongoing coronavirus disease 19 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become fatal for the world with affected population crossing over 25 million in more than 217 countries, consequently declared a global pandemic by the World Health Organization. Unfortunately, neither specific prophylactic or therapeutic drugs nor vaccines are available. To address the unmet medical needs, we explored a strategy identifying new compounds targeting the main protease (Mpro) of SARS-CoV-2. Targeting the SARS-CoV-2 Mpro crystal structure (PDB ID: 6LU7) a combination of in silico screening, molecular docking, and dynamic approaches, a set of 5000 compounds of the ZINC database were screened. As a result, we identified and ranked the top 20 compounds based on the scores of ligand-interaction, their drug-likeness properties, and their predicted antiviral efficacies. The prominent drug-like and potent inhibitory compounds are 2-[2-(2-aminoacetyl) aminoacetyl] amino-3-(4-hydroxyphenyl)-propanamide (ZINC000004762511), 6'-fluoroaristeromycin (ZINC000001483267) and cyclo (L-histidyl-L-histidyl) (ZINC000005116916) scaffolds. Further in vitro and in vivo validations are required to demonstrate anti-SARS-CoV-2 activities.

Coronavirus disease 2019-Historical context, virology, pathogenesis, immunotherapy, and vaccine development

The current Coronavirus Disease 2019 (COVID-19) pandemic is causing great alarm around the world. The pathogen for COVID-19 - severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) - is the seventh known coronavirus to cause pneumonia in humans. While much remains unknown about SARS-CoV-2, physicians and researchers have begun to publish relevant findings, and much evidence is available on coronaviruses previously circulating in human and animal populations. In this review, we situate COVID-19 in its context as a transboundary viral disease, and provide a comprehensive discussion focused on the discovery, spread, virology, pathogenesis, and clinical features of this disease, its causative coronaviral pathogen, and approaches to combating the disease through immunotherapies and other treatments and vaccine development. An epidemiological survey revealed a potentially large number of asymptomatic SARS-CoV-2 carriers within the population, which may hamper efforts against COVID-19. Finally, we emphasize that vaccines against SARS-CoV-2, which may be developed by 2021, will be essential for prevention of COVID-19.

Targeting Host Innate and Adaptive Immunity to Achieve the Functional Cure of Chronic Hepatitis B

Despite the availability of an effective preventive vaccine for hepatitis B virus (HBV) for over 38 years, chronic HBV (CHB) infection remains a global health burden with around 257 million patients. The ideal treatment goal for CHB infection would be to achieve complete cure; however, current therapies such as peg-interferon and nucleos(t)ide analogs are unable to achieve the functional cure, the newly set target for HBV chronic infection. Considering the fact functional cure has been accepted as an endpoint in the treatment of chronic hepatitis B by scientific committee, the development of alternative therapeutic strategies is urgently needed to functionally cure CHB infection. A promising target for future therapeutic strategies is immune modulation to restore dysfunctional HBV-specific immunity. In this review, we provide an overview of the progress in alternative therapeutic strategies, including immune-based therapeutic approaches that enhance host innate and adaptive immunity to achieve and increase the functional cure from CHB infection.

A Novel Cytological Model of B-Cell/Macrophage Biphenotypic Cell Hodgkin Lymphoma in Ganp-Transgenic Mice

Hodgkin lymphoma (HL) is one of the most difficult neoplasms in terms of cytopathological research owing to the lack of established cytological murine models. Although HL is believed to be of lymphoid germinal center B-cell origin, HL cells exhibit unique biphenotypic characteristics of B cells and macrophages. B-cell/macrophage biphenotypic cells have also been identified in the spleen of Lyn-deficient mice. Moreover, Lyn-targeting germinal center-associated nuclear protein (GANP)-transgenic mice (Ig-ganp^Tg mice) spontaneously develop a lymphoid tumor. We aimed to investigate whether the lymphoid tumor developed in Ig-ganp^Tg mice exhibit biphenotypic characteristics of B cells/macrophages that correspond to human HL. Here, we demonstrated GANP overexpression in human HL cells and found that it may regulate transdifferentiation between B cells and macrophages. We also demonstrated that tumors were comparable with B-cell/macrophage biphenotypic Hodgkinoid lymphomas. The tumor cells expressed macrophage-related F4/80, CD68, and CD204 as well as cytoplasmic B220 and µ-/κ-chains; in addition, these cells exhibited phagocytic activity. These cells also expressed transcripts of CD30; c-fms; and the cytokines monocyte chemoattractant protein (MCP)-1, MCP-5, RANTES, tumor necrosis factor-α and thrombopoietin associated with macrophages as well as granulocyte/macrophage colony-stimulating factor, interleukin (IL)-4, IL-10, IL-12, and IL-13. Ig-ganp^Tg mice represent a novel cytological model for the study of cytopathological etiology and oncogenesis of HL.

Intranasal vaccination with HBs and HBc protein combined with carboxyl vinyl polymer induces strong neutralizing antibody, anti-HBs IgA, and IFNG response

Hepatitis B virus (HBV) infection causes acute and chronic hepatitis, which is a major public health concern worldwide. Immunization methods incorporating hepatitis B surface-small (HBs-S) antigen and hepatitis B core antigen (HBc) have been proposed as candidate therapeutic vaccines, but the elimination of existing HBV infection remains a challenge. To enhance the efficacy of HBs and HBc vaccination, we investigated HBs-large (HBs-L) as an immunogen, and carboxyl vinyl polymer (CVP) as an excipient. HBs-S or HBs-L, in combination with HBc antigen, was administered subcutaneously (without CVP) or intranasally (with or without CVP) for the evaluation of immune response in the tree shrew, which is considered to be a suitable small animal model of HBV infection. Immunization with HBs-L antigen by either route induced a rapid IgG response. Intranasal immunization with HBs-S or HBs-L and HBc formulated with CVP strongly induced neutralizing antibody activity, IgA response, and HBc-specific expression of the interferon gamma-encoding gene. These data indicated the potential of HBs-L and HBc intranasal immunization with CVP, not only as a therapeutic vaccine, but also as a prophylactic vaccine candidate.