Dermal macrophages set pain sensitivity by modulating the amount of tissue NGF through an SNX25-Nrf2 pathway.

Cross-talk between peripheral neurons and immune cells is important in pain sensation. We identified Snx25 as a pain-modulating gene in a transgenic mouse line with reduced pain sensitivity. Conditional deletion of Snx25 in monocytes and macrophages, but not in peripheral sensory neurons, in mice (Snx25cKO mice) reduced pain responses in both normal and neuropathic conditions. Bone marrow transplantation using Snx25cKO and wild-type mice indicated that macrophages modulated pain sensitivity. Expression of sorting nexin (SNX)25 in dermal macrophages enhanced expression of the neurotrophic factor NGF through the inhibition of ubiquitin-mediated degradation of Nrf2, a transcription factor that activates transcription of Ngf. As such, dermal macrophages set the threshold for pain sensitivity through the production and secretion of NGF into the dermis, and they may cooperate with dorsal root ganglion macrophages in pain perception.

Angiopoietin-like 4 Is a Critical Regulator of Fibroblasts during Pulmonary Fibrosis Development.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible interstitial pneumonia caused by the excessive production and deposition of extracellular matrix components, including type I collagen. Activated fibroblasts, called α-SMA (α-smooth muscle actin)-expressing myofibroblasts, are the major source of type I collagen in pulmonary fibrosis (PF), but the mechanisms underlying disease progression have not been fully elucidated. Here, we obtained lung fibroblasts from patients with IPF from both nonfibrotic and fibrotic areas as determined by a lung computed tomography scan and compared gene expression between these areas by DNA microarray. We found that ANGPTL4 (angiopoietin-like 4) was highly expressed only in fibroblasts from the fibrotic area. ANGPTL4 was selectively expressed in the fibroblastic area of IPF lungs, where the myofibroblast marker α-SMA was also expressed. ANGPTL4 also regulates the gene expression of fibrosis-related markers, cell migration, and proliferation. In addition, ANGPTL4 expression in a murine model of PF induced by treatment with bleomycin was significantly induced in the lungs from the acute to the chronic phase. Single-cell transcriptome analysis during the course of bleomycin-induced PF revealed that Angptl4 was predominantly expressed in the activated fibroblasts and myofibroblasts. Moreover, the administration of recombinant ANGPTL4 to the bleomycin-induced fibrosis model significantly increased collagen deposition and exacerbated the PF. In contrast, the pathogenesis of PF in Angptl4-deficient mice was improved. These results indicate that ANGPTL4 is critical for the progression of PF and might be an early diagnostic marker and therapeutic target for IPF.

A Disintegrin and Metalloproteinase with Thrombospondin Motifs 4 Regulates Pulmonary Vascular Hyperpermeability through Destruction of Glycocalyx in Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) has no specific and effective treatment, and there is an urgent need to understand its pathogenesis. Therefore, based on the hypothesis that molecules whose expression is upregulated in injured pulmonary vascular endothelial cells (VECs) are involved in the pathogenesis of ARDS, we conducted a study to elucidate the molecular mechanisms and identify target factors for treatment. Primary human lung microvascular endothelial cells (HMVEC-Ls) were stimulated with lipopolysaccharide (LPS) or poly (I:C) and analyzed via a microarray to identify target genes for ARDS. We found that a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4) was induced in murine lung VECs in an LPS-mediated ARDS model. Elevated ADAMTS4 was also observed by the immunostaining of lung samples from ARDS patients. The suppression of ADAMTS4 by siRNA in VECs ameliorated LPS-stimulated vascular permeability. The impairment of the cell surface expression of syndecan-1, a marker of the glycocalyx that is an extracellular matrix involved in vascular permeability, was dramatically inhibited by ADAMTS4 suppression. In addition, the suppression of ADAMTS4 protected against LPS-induced reductions in syndecan-1 and the adherens junction protein vascular endothelial cadherin. These results suggest that ADAMTS4 regulates VEC permeability in ARDS and may be a predictive marker and therapeutic target for ARDS.

Responses of perivascular macrophages to circulating lipopolysaccharides in the subfornical organ with special reference to endotoxin tolerance.

BACKGROUND: Circulating endotoxins including lipopolysaccharides (LPS) cause brain responses such as fever and decrease of food and water intake, while pre-injection of endotoxins attenuates these responses. This phenomenon is called endotoxin tolerance, but the mechanisms underlying it remain unclear. The subfornical organ (SFO) rapidly produces proinflammatory cytokines including interleukin-1ß (IL-1ß) in response to peripherally injected LPS, and repeated LPS injection attenuates IL-1ß production in the SFO, indicating that the SFO is involved in endotoxin tolerance. The purpose of this study is to investigate features of the IL-1ß source cells in the SFO of LPS-non-tolerant and LPS-tolerant mice. METHODS: We first established the endotoxin-tolerant mouse model by injecting LPS into adult male mice (C57BL/6J). Immunohistochemistry was performed to characterize IL-1ß-expressing cells, which were perivascular macrophages in the SFO. We depleted perivascular macrophages using clodronate liposomes to confirm the contribution of IL-1ß production. To assess the effect of LPS pre-injection on perivascular macrophages, we transferred bone marrow-derived cells obtained from male mice (C57BL/6-Tg (CAG-EGFP)) to male recipient mice (C57BL/6N). Finally, we examined the effect of a second LPS injection on IL-1ß expression in the SFO perivascular macrophages. RESULTS: We report that perivascular macrophages but not parenchymal microglia rapidly produced the proinflammatory cytokine IL-1ß in response to LPS. We found that peripherally injected LPS localized in the SFO perivascular space. Depletion of macrophages by injection of clodronate liposomes attenuated LPS-induced IL-1ß expression in the SFO. When tolerance developed to LPS-induced sickness behavior in mice, the SFO perivascular macrophages ceased producing IL-1ß, although bone marrow-derived perivascular macrophages increased in number in the SFO and peripherally injected LPS reached the SFO perivascular space. CONCLUSIONS: The current data indicate that perivascular macrophages enable the SFO to produce IL-1ß in response to circulating LPS and that its hyporesponsiveness may be the cause of endotoxin tolerance.

JNK regulatory molecule G5PR induces IgG autoantibody-producing plasmablasts from peritoneal B1a cells.

Peritoneal B1a cells expressing CD5 and CD11b generate autoantibody-producing precursors in autoimmune-prone mice. Previous studies show reduced JNK signaling in peritoneal B1a cells of female New Zealand Black mice and an abnormal increase of protein phosphatase 2A subunit G5PR that regulates BCR-mediated JNK signaling as a cause of autoimmunity. To investigate the mechanism regulating B1a differentiation into autoantibody-secreting plasmablasts (PBs), we applied an in vitro culture system that supports long-term growth of germinal center (GC) B cells (iGB) with IL-4, CD40L, and BAFF. Compared with spleen B2 cells, B1a cells differentiated into GC-like B cells, but more markedly into PBs, and underwent class switching toward IgG1. During iGB culture, B1a cells expressed GC-associated aicda, g5pr, and bcl6, and markedly PB-associated prdm1, irf4, and xbp1. B1a-derived iGB cells from New Zealand Black × New Zealand White F1 mice highly differentiated into autoantibody-secreting PBs in vitro and localized to the GC area in vivo. In iGB culture, JNK inhibitor SP600125 augmented the differentiation of C57BL/6 B1a cells into PBs. Furthermore, B1a cells from G5PR transgenic mice markedly differentiated into IgM and IgG autoantibody-secreting PBs. In conclusion, JNK regulation is critical to suppress autoantibody-secreting PBs from peritoneal B1a cells.

Transgenic overexpression of G5PR that is normally augmented in centrocytes impairs the enrichment of high-affinity antigen-specific B cells, increases peritoneal B-1a cells, and induces autoimmunity in aged female mice.

To investigate signals that control B cell selection, we examined expression of G5PR, a regulatory subunit of the serine/threonine protein phosphatase 2A, which suppresses JNK phosphorylation. G5PR is upregulated in activated B cells, in Ki67-negative centrocytes at germinal centers (GCs), and in purified B220(+)Fas(+)GL7(+) mature GC B cells following Ag immunization. G5PR rescues transformed B cells from BCR-mediated activation-induced cell death by suppression of late-phase JNK activation. In G5PR-transgenic (G5PR(Tg)) mice, G5PR overexpression leads to an augmented generation of GC B cells via an increase in non-Ag-specific B cells and a consequent reduction in the proportion of Ag-specific B cells and high-affinity Ab production after immunization with nitrophenyl-conjugated chicken γ-globulin. G5PR overexpression impaired the affinity-maturation of Ag-specific B cells, presumably by diluting the numbers of high-affinity B cells. However, aged nonimmunized female G5PR(Tg) mice showed an increase in the numbers of peritoneal B-1a cells and the generation of autoantibodies. G5PR overexpression did not affect the proliferation of B-1a and B-2 cells but rescued B-1a cells from activation-induced cell death in vitro. G5PR might play a pivotal role in B cell selection not only for B-2 cells but also for B-1 cells in peripheral lymphoid organs.

Lyn signaling to upregulate GANP is critical for the survival of high-affinity B cells in germinal centers of lymphoid organs.

Signals through BCR and costimulatory molecules play essential roles in selecting high-affinity B cells with Ig V-region mutations in the germinal centers (GCs) of peripheral lymphoid organs. Lyn-deficient (lyn(-/-)) mice show impaired BCR signal triggering for cell proliferation and GC formation, causing hyper-IgM, and display autoimmunity after aging. In this study, we demonstrate that Lyn-mediated signaling to upregulate GANP is essential for the survival of mature GC-like (mGC) B cells with high-affinity type BCR mutations upon Ag immunization. Transgenic ganp expression into lyn(-/-) mice did not recover the Lyn-deficient phenotype with regard to B cell differentiation, serum Igs, and impaired GC formation in spleens after immunization with nitrophenyl-chicken γ-globulin, but it markedly rescued cell survival of mGC B cells by suppressing DNA damage, thereby increasing the frequency of the Trp(33)-to-Leu mutation in the IgV(H)-186.2 region and affinity maturation of nitrophenyl-binding B cells. GANP may play a critical role in Lyn-mediated signaling for the selection of high-affinity B cells in peripheral lymphoid organs.

CD8+ T cell memory induced by successive SARS-CoV-2 mRNA vaccinations is characterized by shifts in clonal dominance.

mRNA vaccines against the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) elicit strong T cell responses. However, a clonal-resolution analysis of T cell responses to mRNA vaccination has not been performed. Here, we temporally track the CD8+ T cell repertoire in individuals who received three shots of the BNT162b2 mRNA vaccine through longitudinal T cell receptor sequencing with peptide-human leukocyte antigen (HLA) tetramer analysis. We demonstrate a shift in T cell responses between the clonotypes with different kinetics: from early responders that expand rapidly after the first shot to main responders that greatly expand after the second shot. Although the main responders re-expand after the third shot, their clonal diversity is skewed, and newly elicited third responders partially replace them. Furthermore, this shift in clonal dominance occurs not only between, but also within, clonotypes specific for spike epitopes. Our study will be a valuable resource for understanding vaccine-induced T cell responses in general.

Breast cancers with high DSS1 expression that potentially maintains BRCA2 stability have poor prognosis in the relapse-free survival.

BACKGROUND: Genetic BRCA2 insufficiency is associated with breast cancer development; however, in sporadic breast cancer cases, high BRCA2 expression is paradoxically correlated with poor prognosis. Because DSS1, a mammalian component of the transcription/RNA export complex, is known to stabilize BRCA2, we investigated how the expression of DSS1 is associated with clinical parameters in breast cancers. METHODS: DSS1 mRNA and p53 protein were examined by RT-PCR and immunohistochemical staining of breast cancer specimens to classify DSS1(high) and DSS1(low) or p53(high) and p53(low) groups. Patient survival was compared using Kaplan-Meier method. DSS1(high) or DSS1(low) breast cancer cells were prepared by retroviral cDNA transfection or DSS1 siRNA on proliferation, cell cycle progression, and survival by flow cytometric analyses with or without anti-cancer drugs. RESULTS: In comparison to patients with low levels of DSS1, high-DSS1 patients showed a poorer prognosis, with respect to relapse-free survival period. The effect of DSS1 was examined in breast cancer cells in vitro. DSS1 high-expression reduces the susceptibility of MCF7 cells to DNA-damaging drugs, as observed in cell cycle and apoptosis analyses. DSS1 knockdown, however, increased the susceptibility to the DNA-damaging drugs camptothecin and etoposide and caused early apoptosis in p53 wild type MCF7 and p53-insufficient MDA-MB-231 cells. DSS1 knockdown suppresses the proliferation of drug-resistant MDA-MB-231 breast cancer cells, particularly effectively in combination with DNA-damaging agents. CONCLUSION: Breast cancers with high DSS1 expression have worse prognosis and shorter relapse-free survival times. DSS1 is necessary to rescue cells from DNA damage, but high DSS1 expression increases drug resistance. We suggest that DSS1 expression could be a useful marker for drug resistance in breast cancers, and DSS1 knockdown can induce tumor apoptosis when used in combination with DNA-damaging drugs.

Dietary Phenolic Compounds: Their Health Benefits and Association with the Gut Microbiota.

Oxidative stress causes various diseases, such as type II diabetes and dyslipidemia, while antioxidants in foods may prevent a number of diseases and delay aging by exerting their effects in vivo. Phenolic compounds are phytochemicals such as flavonoids which consist of flavonols, flavones, flavanonols, flavanones, anthocyanidins, isoflavones, lignans, stilbenoids, curcuminoids, phenolic acids, and tannins. They have phenolic hydroxyl groups in their molecular structures. These compounds are present in most plants, are abundant in nature, and contribute to the bitterness and color of various foods. Dietary phenolic compounds, such as quercetin in onions and sesamin in sesame, exhibit antioxidant activity and help prevent cell aging and diseases. In addition, other kinds of compounds, such as tannins, have larger molecular weights, and many unexplained aspects still exist. The antioxidant activities of phenolic compounds may be beneficial for human health. On the other hand, metabolism by intestinal bacteria changes the structures of these compounds with antioxidant properties, and the resulting metabolites exert their effects in vivo. In recent years, it has become possible to analyze the composition of the intestinal microbiota. The augmentation of the intestinal microbiota by the intake of phenolic compounds has been implicated in disease prevention and symptom recovery. Furthermore, the "brain-gut axis", which is a communication system between the gut microbiome and brain, is attracting increasing attention, and research has revealed that the gut microbiota and dietary phenolic compounds affect brain homeostasis. In this review, we discuss the usefulness of dietary phenolic compounds with antioxidant activities against some diseases, their biotransformation by the gut microbiota, the augmentation of the intestinal microflora, and their effects on the brain-gut axis.

Antiviral Effect of Candies Containing Persimmon-Derived Tannin against SARS-CoV-2 Delta Strain.

Inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the mouth has the potential to reduce the spread of coronavirus disease 2019 (COVID-19), due to the virus being readily transmitted by dispersed saliva. Persimmon-derived tannin has strong antioxidant and antimicrobial activity owing to its strong adhesion to proteins, and it also exhibited antiviral effects against non-variant and Alpha-variant SARS-CoV-2 in our previous study. In this study, we first demonstrated the antiviral effects of persimmon-derived tannin against the Delta variant of SARS-CoV-2 in vitro via the plaque assay method. We then examined the effects of candy containing persimmon-derived tannin. Remarkably, the saliva samples provided by healthy volunteers while they were eating tannin-containing candy showed that the virus titers of the SARS-CoV-2 Delta variant were suppressed. In addition, we found that the SARS-CoV-2 viral load in saliva from patients with COVID-19 collected immediately after they had eaten the tannin-containing candy was below the level of detection via PCR for SARS-CoV-2. These data suggest that adding persimmon-derived tannin to candy and holding such candy in the mouth is an effective method for inactivating SARS-CoV-2 in saliva, and the application of this approach shows potential for inhibiting the transmission of COVID-19.

The spleen is the major site for the development and expansion of inhibitor producing-cells in hemophilia A mice upon FVIII infusion developing high-titer inhibitor.

BACKGROUND: Hemophilia A (HA) is a hereditary bleeding disorder caused by defects in endogenous factor (F)VIII. Approximately 30 % of patients with severe HA treated with FVIII develop neutralizing antibodies (inhibitors) against FVIII, which render the therapy ineffective. The managements of HA patients with high-titter inhibitors are especially challenging. Therefore, it is important to understand the mechanism(s) of high-titer inhibitor development and dynamics of FVIII-specific plasma cells (FVIII-PCs). AIMS: To identify the dynamics of FVIII-PCs and the lymphoid organs in which FVIII-PCs are localized during high-titer inhibitor formation. METHODS AND RESULTS: When FVIII-KO mice were intravenously injected with recombinant (r)FVIII in combination with lipopolysaccharide (LPS), a marked enhancement of anti-FVIII antibody induction was observed with increasing FVIII-PCs, especially in the spleen. When splenectomized or congenitally asplenic FVIII-KO mice were treated with LPS + rFVIII, the serum inhibitor levels decreased by approximately 80 %. Furthermore, when splenocytes or bone marrow (BM) cells from inhibitor+ FVIII-KO mice treated with LPS + rFVIII were grafted into immune-deficient mice, anti-FVIII IgG was detected only in the serum of splenocyte-administered mice and FVIII-PCs were detected in the spleen but not in the BM. In addition, when splenocytes from inhibitor+ FVIII-KO mice were grafted into splenectomized immuno-deficient mice, inhibitor levels were significantly reduced in the serum. CONCLUSION: The spleen is the major site responsible for the expansion and retention of FVIII-PCs in the presence of high-titer inhibitors.

THE CRITICAL ROLE OF THE HISTONE MODIFICATION ENZYME SETDB2 IN THE PATHOGENESIS OF ACUTE RESPIRATORY DISTRESS SYNDROME.

ABSTRACT: Introduction: Acute respiratory distress syndrome (ARDS) is a severe hypoxemic respiratory failure with a high in-hospital mortality. However, the molecular mechanisms underlying ARDS remain unclear. Recent findings have indicated that the onset of severe inflammatory diseases, such as sepsis, is regulated by epigenetic changes. We investigated the role of epigenetic changes in ARDS pathogenesis using mouse models and human samples. Methods: Acute respiratory distress syndrome was induced in a mouse model (C57BL/6 mice, myeloid cell or vascular endothelial cell [VEC]-specific SET domain bifurcated 2 [Setdb2]-deficient mice [Setdb2 ff Lyz2 Cre+ or Setdb2 ff Tie2 Cre+ ], and Cre - littermates) by intratracheal administration of lipopolysaccharide (LPS). Analyses were performed at 6 and 72 h after LPS administration. Sera and lung autopsy specimens from ARDS patients were examined. Results: In the murine ARDS model, we observed high expression of the histone modification enzyme SET domain bifurcated 2 ( Setdb2 ) in the lungs. In situ hybridization examination of the lungs revealed Setdb2 expression in macrophages and VECs. The histological score and albumin level of bronchoalveolar lavage fluid were significantly increased in Setdb2 ff Tie2 Cre+ mice following LPS administration compared with Setdb2 ff Tie2 Cre- mice, whereas there was no significant difference between the control and Setdb2 ff Lyz2 Cre+ mice. Apoptosis of VECs was enhanced in Setdb2 ff Tie2 Cre+ mice. Among the 84 apoptosis-related genes, the expression of TNF receptor superfamily member 10b ( Tnfrsf10b ) was significantly higher in Setdb2 ff Tie2 Cre+ mice than in control mice. Acute respiratory distress syndrome patients' serum showed higher SETDB2 levels than those of healthy volunteers. SETDB2 levels were negatively correlated with the partial pressure of oxygen in arterial blood/fraction of inspiratory oxygen concentration ratio. Conclusion: Acute respiratory distress syndrome elevates Setdb2 , apoptosis of VECs, and vascular permeability. Elevation of histone methyltransferase Setdb2 suggests the possibility to histone change and epigenetic modification. Thus, Setdb2 may be a novel therapeutic target for controlling the pathogenesis of ARDS.

Transition of Antibody Titers after SARS-CoV-2 mRNA Vaccination in Japanese Healthcare Workers.

Since February 2021, healthcare workers in Japan have been preferentially vaccinated with a messenger RNA vaccine (BNT162b2; Pfizer/BioNTech) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While many studies have confirmed that this vaccine is highly effective in reducing hospitalization and deaths from coronavirus disease 2019 (COVID-19), antibody titers tend to decline at 3 months after vaccination, leading to a risk of breakthrough infections. Thus, information is needed to support the decision regarding the 3rd vaccination. In this study, we investigated the transition of anti-SARS-CoV-2 spike protein receptor-binding domain (RBD) IgG and neutralizing antibody titers in 37 vaccinated Japanese healthcare workers. Samples were collected 6 times starting before vaccination until 6 months after the second vaccination. The levels of anti-SARS-CoV-2 RBD IgG peaked 1 week after the 2nd vaccination, then declined over time and decreased to < 10% at 6 months after the 2nd vaccination. Additionally, approximately one-third of the healthcare workers were seronegative for the Omicron variant 6 months after the 2nd vaccination. Workers with low anti-SARS-CoV-2 RBD IgG levels also had low neutralizing antibody titers. These data support booster dose administration for healthcare workers, especially those with low anti-SARS-CoV-2 RBD IgG levels.

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.

Selective cell death of p53-insufficient cancer cells is induced by knockdown of the mRNA export molecule GANP.

Cancer cells often contain p53 abnormalities that impair cell-cycle checkpoint progression and cause resistance to various anti-cancer treatments. DNA damage occurs at actively transcribed genes during G1-phase in yeast cells that have a deficient mRNA export capacity. Here, we show that germinal center-associated nuclear protein (GANP), a homologue of yeast Sac3 that is involved in mRNA export, is indispensable for ensuring the stability of human genomic DNA and that GANP knockdown causes apoptosis and necrosis of p53-insufficient cancer cells. Ganp small interfering RNA (siGanp)-induced DNA damage, accompanied by a decrease in the number of cells in S-phase, caused late apoptosis and necrosis in p53-insufficient cancer cells through both caspase-dependent and -independent mechanisms. siGanp effectively induced DNA damage leading to cell death in p53-insufficient cancer cells in vitro and protect the growth of cancer cells transplanted into immunocompromized mice, suggesting that siGanp has potential as a selective treatment for p53-insufficient cancer cells.

Critical role of Pcid2 in B cell survival through the regulation of MAD2 expression.

The mitotic checkpoint is essential for maintaining genomic stability in differentiating B cells undergoing genetic alterations of the Ig gene. In this study, using real-time RT-PCR and in situ RNA hybridization, we demonstrated that MAD2 mRNA export is selectively regulated by Pcid2/Thp1. Pcid2 small interfering RNA induced a cell-cycle abnormality with increased apoptosis and polyploidy, as previously observed in MAD2-knockdown cells. Pcid2 small interfering RNA reduced MAD2 expression, but not the expression of other cell-cycle checkpoint proteins, such as MAD1 and BUBR1, or the cell-cycle-associated proteins, cyclin A, cyclin B1, and cyclin-dependent kinase 1. In mouse B lineage cells, Pcid2 transcripts appeared in a stage-dependent manner at high levels in bone marrow pre-B and immature B cells, and in spleen transitional 1 and follicular B cells, but at lower levels in pro-B, transitional 2, and marginal zone B cells, suggesting a stage-dependent requirement for MAD2 regulation. Cd19-cre-derived targeting of the Pcid2 gene induced a mature B cell deficiency in mice. These findings indicate that Pcid2 is essential for B cell survival through the regulation of MAD2 expression during B cell differentiation.

Antioxidant Potential of Non-Extractable Fractions of Dried Persimmon (Diospyros kaki Thunb.) in Streptozotocin-Induced Diabetic Rats.

Oxidative stress causes the progression of diabetes and its complications; thus, maintaining the balance between reactive oxygen species produced by hyperglycemia and the antioxidant defense system is important. We herein examined the antioxidant potential of non-extractable fractions of dried persimmon (NEP) against oxidative stress in diabetic rats. Rats with streptozotocin-induced type 1 diabetes (50 mg/kg body weight) were administered NEP for 9 weeks. Antioxidant enzyme activities and concentration of antioxidants in liver tissues were analyzed with a microplate reader. Extensor digitorum longus (EDL) and soleus muscle fibers were stained with succinate dehydrogenase and muscle fiber sizes were measured. The administration of NEP increased the body weight of diabetes rats. Regarding antioxidant activities, the oxygen radical absorbance capacity and superoxide dismutase activity in liver tissues significantly increased. In addition, increases in glutathione peroxidase activity in liver tissues and reductions in the cross-sectional area of EDL muscle fibers were significantly suppressed. In these results, NEP improved the antioxidant defense system in the liver tissues of diabetic rats, in addition to attenuating of muscle fibers atrophy against oxidative damage induced by hyperglycemia.

Oral SARS-CoV-2 Inoculation Causes Nasal Viral Infection Leading to Olfactory Bulb Infection: An Experimental Study.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can cause long-lasting anosmia, but the impact of SARS-CoV-2 infection, which can spread to the nasal cavity via the oral route, on the olfactory receptor neuron (ORN) lineage and olfactory bulb (OB) remains undetermined. Using Syrian hamsters, we explored whether oral SARS-CoV-2 inoculation can lead to nasal viral infection, examined how SARS-CoV-2 affects the ORN lineage by site, and investigated whether SARS-CoV-2 infection can spread to the OB and induce inflammation. On post-inoculation day 7, SARS-CoV-2 presence was confirmed in the lateral area (OCAM-positive) but not the nasal septum of NQO1-positive and OCAM-positive areas. The virus was observed partially infiltrating the olfactory epithelium, and ORN progenitor cells, immature ORNs, and mature ORNs were fewer than in controls. The virus was found in the olfactory nerve bundles to the OB, suggesting the nasal cavity as a route for SARS-CoV-2 brain infection. We demonstrated that transoral SARS-CoV-2 infection can spread from the nasal cavity to the central nervous system and the possibility of central olfactory dysfunction due to SARS-CoV-2 infection. The virus was localized at the infection site and could damage all ORN-lineage cells.

Evidence for the spread of SARS-CoV-2 and olfactory cell lineage impairment in close-contact infection Syrian hamster models.

Objectives: Close contact with patients with COVID-19 is speculated to be the most common cause of viral transmission, but the pathogenesis of COVID-19 by close contact remains to be elucidated. In addition, despite olfactory impairment being a unique complication of COVID-19, the impact of SARS-CoV-2 on the olfactory cell lineage has not been fully validated. This study aimed to elucidate close-contact viral transmission to the nose and lungs and to investigate the temporal damage in the olfactory receptor neuron (ORN) lineage caused by SARS-CoV-2. Methods: Syrian hamsters were orally administered SARS-CoV-2 nonvariant nCoV-19/JPN/TY/WK521/2020 as direct-infection models. On day 3 after inoculation, infected and uninfected hamsters were housed in the same cage for 30 minutes. These uninfected hamsters were subsequently assigned to a close-contact group. First, viral presence in the nose and lungs was verified in the infection and close-contact groups at several time points. Next, the impacts on the olfactory epithelium, including olfactory progenitors, immature ORNs, and mature ORNs were examined histologically. Then, the viral transmission status and chronological changes in tissue damage were compared between the direct-infection and close-contact groups. Results: In the close-contact group, viral presence could not be detected in both the nose and lungs on day 3, and the virus was identified in both tissues on day 7. In the direct-infection group, the viral load was highest in the nose and lungs on day 3, decreased on day 7, and was no longer detectable on day 14. Histologically, in the direct-infection group, mature ORNs were most depleted on day 3 (p <0.001) and showed a recovery trend on day 14, with similar trends for olfactory progenitors and immature ORNs. In the close-contact group, there was no obvious tissue damage on day 3, but on day 7, the number of all ORN lineage cells significantly decreased (p <0.001). Conclusion: SARS-CoV-2 was transmitted even after brief contact and subsequent olfactory epithelium and lung damage occurred more than 3 days after the trigger of infection. The present study also indicated that SARS-CoV-2 damages all ORN lineage cells, but this damage can begin to recover approximately 14 days post infection.