17ß-Estradiol (E2) Activates Matrix Mineralization through Genomic/Nongenomic Pathways in MC3T3-E1 Cells.

Estrogen plays an important role in osteoporosis prevention. We herein report the possible novel signaling pathway of 17ß-estradiol (E2) in the matrix mineralization of MC3T3-E1, an osteoblast-like cell line. In the culture media-containing stripped serum, in which small lipophilic molecules such as steroid hormones including E2 were depleted, matrix mineralization was significantly reduced. However, the E2 treatment induced this. The E2 effects were suppressed by ICI182,780, the estrogen receptor (ER)α, and the ERß antagonist, as well as their mRNA knockdown, whereas Raloxifene, an inhibitor of estrogen-induced transcription, and G15, a G-protein-coupled estrogen receptor (GPER) 1 inhibitor, had little or no effect. Furthermore, the E2-activated matrix mineralization was disrupted by PMA, a PKC activator, and SB202190, a p38 MAPK inhibitor, but not by wortmannin, a PI3K inhibitor. Matrix mineralization was also induced by the culture media from the E2-stimulated cell culture. This effect was hindered by PMA or heat treatment, but not by SB202190. These results indicate that E2 activates the p38 MAPK pathway via ERs independently from actions in the nucleus. Such activation may cause the secretion of certain signaling molecule(s), which inhibit the PKC pathway. Our study provides a novel pathway of E2 action that could be a therapeutic target to activate matrix mineralization under various diseases, including osteoporosis.

Loss of PARP7 Increases Type I Interferon Signaling in EO771 Breast Cancer Cells and Prevents Mammary Tumor Growth by Increasing Antitumor Immunity.

PARP7 is a member of the ADP-ribosyltransferase diphtheria toxin-like (ARTD) family and acts as a repressor of type I interferon (IFN) signaling. PARP7 inhibition causes tumor regression by enhancing antitumor immunity, which is dependent on the stimulator of interferon genes (STING) pathway, TANK-binding kinase 1 (TBK1) activity, and cytotoxic CD8+ T cells. To better understand PARP7's role in cancer, we generated and characterized PARP7 knockout (Parp7KO) EO771 mouse mammary cancer cells in vitro and in a preclinical syngeneic tumor model using catalytic mutant Parp7H532A mice. Loss of PARP7 expression or inhibition of its activity increased type I IFN signaling, as well as the levels of interferon-stimulated gene factor 3 (ISGF3) and specifically unphosphorylated-ISGF3 regulated target genes. This was partly because PARP7's modification of the RelA subunit of nuclear factor κ-B (NF-κB). PARP7 loss had no effect on tumor growth in immunodeficient mice. In contrast, injection of wildtype cells into Parp7H532A mice resulted in smaller tumors compared with cells injected into Parp7+/+ mice. Parp7H532A mice injected with Parp7KO cells failed to develop tumors and those that developed regressed. Our data highlight the importance of PARP7 in the immune cells and further support targeting PARP7 for anticancer therapy.

Augmented interferon regulatory factor 7 axis in whole tumor cell vaccines prevents tumor recurrence by inducing interferon gamma-secreting B cells.

Among cancer immunotherapy, which has received great attention in recent years, cancer vaccines can potentially prevent recurrent tumors by using the exquisite power and specificity of the immune system. Specifically, whole tumor cell vaccines (WTCVs) based on surgically resected tumors have been considered to elicit robust anti-tumor immune responses by exposing various tumor-associated antigens to host immunity. However, most tumors have little immunogenicity because of immunoediting by continuous interactions with host immunity; thus, preparing WTCVs based on patient-derived non-modified tumors cannot prevent tumor onset. Hence, the immunogenicity of tumor cells must be improved for effective WTCVs. In this study, we indicate the importance of the interferon regulatory factor 7 (Irf7) axis, including Irf7 and its downstream factors, within tumor cells in regulating immunogenicity. Indeed, WTCVs that augmented the Irf7 axis have exerted remarkable recurrence-preventive effects when vaccinated after tumor inactivation by radiation. Most notably, vaccination with murine colon cancer cells that enhanced the Irf7 axis prevented the development of challenged tumors in all mice and resulted in a 100% survival rate during the observation period. Furthermore, the mechanism leading to vaccine effectiveness was mediated by interferon-gamma-producing B cells. This study provides novel insights into how to enhance tumor immunogenicity and use WTCVs as recurrence prophylaxis.

RIG-I triggers a signaling-abortive anti-SARS-CoV-2 defense in human lung cells.

Efficient immune responses against viral infection are determined by sufficient activation of nucleic acid sensor-mediated innate immunity1,2. Coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains an ongoing global pandemic. It is an urgent challenge to clarify the innate recognition mechanism to control this virus. Here we show that retinoic acid-inducible gene-I (RIG-I) sufficiently restrains SARS-CoV-2 replication in human lung cells in a type I/III interferon (IFN)-independent manner. RIG-I recognizes the 3' untranslated region of the SARS-CoV-2 RNA genome via the helicase domains, but not the C-terminal domain. This new mode of RIG-I recognition does not stimulate its ATPase, thereby aborting the activation of the conventional mitochondrial antiviral-signaling protein-dependent pathways, which is in accordance with lack of cytokine induction. Nevertheless, the interaction of RIG-I with the viral genome directly abrogates viral RNA-dependent RNA polymerase mediation of the first step of replication. Consistently, genetic ablation of RIG-I allows lung cells to produce viral particles that expressed the viral spike protein. By contrast, the anti-SARS-CoV-2 activity was restored by all-trans retinoic acid treatment through upregulation of RIG-I protein expression in primary lung cells derived from patients with chronic obstructive pulmonary disease. Thus, our findings demonstrate the distinctive role of RIG-I as a restraining factor in the early phase of SARS-CoV-2 infection in human lung cells.

Disinfectant potential in inactivation of epidemic keratoconjunctivitis-related adenoviruses by potassium peroxymonosulfate.

PURPOSE: The aim of this study was to test the antiviral effectivity of potassium peroxymonosulfate (RUBYSTA®, KYORIN) against five epidemic keratoconjunctivitis-related types of Human adenovirus D in vitro. METHODS: Five types of Human adenovirus D (8, 37, 53, 54 and 56) were incubated with 1% potassium peroxymonosulfate, 0.1% sodium hypochlorite (NaClO) or alcohol-based disinfectant for 30 s or 1 min. These solutions were subjected to measurements of viral titres by infection assays in A549 cells. At day 6 post-infection, both, supernatants and cells, were collected and the viral genome was assessed by real-time polymerase chain reaction analysis. RESULTS: Treatments with 1% potassium peroxymonosulfate led to significant reduction in all tested Human adenovirus D types comparable to disinfecting effects by 0.1% NaClO. Overall, potassium peroxymonosulfate demonstrated sufficient inactivation of the major epidemic keratoconjunctivitis-causing Human adenovirus D to be considered for disinfection and prevention purposes in ophthalmological clinics and hospitals. CONCLUSION: This study demonstrated that potassium peroxymonosulfate is a promising disinfectant for the prevention of epidemic keratoconjunctivitis nosocomial infections in ophthalmological clinics.

Involvement of Zizimin2/3 in the age-related defect of peritoneal B-1a cells as a source of anti-bacterial IgM.

Zizimin2 (Ziz2), also known as dedicator of cytokinesis 11 (DOCK11), is a guanine nucleotide exchange factor that is predominantly expressed in lymphoid tissues. Recent findings demonstrated that Ziz2 is involved in the development of B cells, including germinal centre B cells and marginal zone B cells. However, limited information is currently available on the roles of Ziz2 in B-1 cells, a B-cell subset that resides in body cavities and contributes to protection against foreign pathogens in a T-cell-independent manner. We herein show that Ziz2 and its widely expressed isoform Ziz3 (also known as DOCK10) may be involved in defective production of anti-bacterial IgM by aged B-1a cells, a CD5+ subset of B-1 cells. Natural IgM against typical bacterial epitopes was defectively produced by peritoneal B-1a cells from aged mice. The down-regulation of Ziz2/3 in B-1a cells appeared to be responsible for this defective IgM production, as demonstrated by Ziz2/3 double-knockout mice. Mechanistically, lower levels of basal AKT phosphorylation did not allow for the differentiation of Ziz2/3-deficient B-1a cells into plasma cells. Defective production of anti-bacterial IgM was not fully rescued by immunization, resulting in slightly weaker protection in Ziz2/3-deficient mice. Thus, the down-regulation of Ziz2/3 in B-1a cells may at least partly account for defective protection in aged mice.

Essential role of HCMV deubiquitinase in promoting oncogenesis by targeting anti-viral innate immune signaling pathways.

Cancer is a multifactorial disease and virus-mediated carcinogenesis is one of the crucial factors, which is poorly understood. Human cytomegalovirus (HCMV) is a herpesvirus and its components have been evidenced to be associated with cancer of different tissue origin. However, its role in cancer remains unknown. Here, we identified a conserved herpesviral tegument protein known as pUL48 of HCMV, encoding deubiquitinase enzyme, as having a key role in carcinogenesis. We show using deubiquitinase sufficient- and deficient-HCMV that HCMV deubiquitinase is a key in inducing enhanced cellular metabolic activity through upregulation of several anti-apoptotic genes and downregulation of several pro-apoptotic genes expression. Furthermore, HCMV deubiquitinase acquires pro-tumor functions by inhibiting PRR-mediated type I interferon via deubiquitination of TRAF6, TRAF3, IRAK1, IRF7 and STING. Taken together, our results suggest that HCMV infection may promote oncogenesis by inhibiting innate immunity of the host.

Helicobacter pylori induces IL-1ß protein through the inflammasome activation in differentiated macrophagic cells.

More than 50% of people in the world are infected with Helicobacter pylori (H. pylori), which induces various gastric diseases. Especially, epidemiological studies have shown that H. pylori infection is a major risk factor for gastric cancer. It has been reported that the levels of interleukin (IL)-1ß are upregulated in gastric tissues of patients with H. pylori infection. In this study, we investigated the induction mechanism of IL-1ß during H. pylori infection. We found that IL-1ßmRNA and protein were induced in phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 cells after H. pylori infection. This IL-1ß production was inhibited by a caspase-1 inhibitor and a ROS inhibitor. Furthermore, K(+) efflux and Ca(2+) signaling were also involved in this process. These data suggest that NOD-like receptor (NLR) family, pyrin domain containing 3 (NLRP3) and its complex, known as NLRP3 inflammasome, are involved in IL-1ß production during H. pylori infection because it is reported that NLRP3 inflammasome is activated by ROS, K(+) efflux and/or Ca(2+) signaling. These findings may provide therapeutic strategy for the control of gastric cancer in H. pylori-infected patients.

The microRNA miR-485 targets host and influenza virus transcripts to regulate antiviral immunity and restrict viral replication.

MicroRNAs (miRNAs) are small noncoding RNAs that are responsible for dynamic changes in gene expression, and some regulate innate antiviral responses. Retinoic acid-inducible gene I (RIG-I) is a cytosolic sensor of viral RNA; RIG-I activation induces an antiviral immune response. We found that miR-485 of the host was produced in response to viral infection and targeted RIG-I mRNA for degradation, which led to suppression of the antiviral response and enhanced viral replication. Thus, inhibition of the expression of mir-485 markedly reduced the replication of Newcastle disease virus (NDV) and the H5N1 strain of influenza virus in mammalian cells. Unexpectedly, miR-485 also bound to the H5N1 gene PB1 (which encodes an RNA polymerase required for viral replication) in a sequence-specific manner, thereby inhibiting replication of the H5N1 virus. Furthermore, miR-485 exhibited bispecificity, targeting RIG-I in cells with a low abundance of H5N1 virus and targeting PB1 in cells with increased amounts of the H5N1 virus. These findings highlight the dual role of miR-485 in preventing spurious activation of antiviral signaling and restricting influenza virus infection.

Stimulation of macrophages with the ß-glucan produced by aureobasidium pullulans promotes the secretion of tumor necrosis factor-related apoptosis inducing ligand (TRAIL).

A ß-glucan produced by Aureobasidium pullulans (AP-PG) is consisting of a ß-(1,3)-linked main chain with ß-(1,6)-linked glucose side residues. Various ß-glucans consisting of ß-(1,3)-linked main chain including AP-PG are believed to exhibit anti-tumor activities, and actually, anti-tumor activities of AP-PG in mice have been demonstrated. In this study, we demonstrate that stimulation with AP-PG induces TRAIL expression in mouse and human macrophage-like cell lines. TRAIL is known to be a cytokine which specifically induces apoptosis in transformed cells, but not in untransformed cells. The expression of TRAIL mRNA after stimulation with AP-PG was increased in RAW264.7 cells, Mono Mac 6 cells, and macrophage-differentiated THP-1 cells. The mRNA expression of TNF-α and FasL is only weakly increased after stimulation with AP-PG. The induction activity of TRAIL by curdlan, a bacterial ß-glucan, was very similar to that by AP-PG in RAW264.7 cells, but weaker in macrophage-differentiated THP-1 cells. Activation of caspases was found in HeLa cells after treatment with the supernatant of cultured medium from AP-PG-stimulated Mono Mac 6 cells, and was inhibited by the anti-TRAIL neutralizing antibody. These findings suggest that the stimulation with AP-PG effectively induces TRAIL in macrophages, and that it may be related to apoptosis induction of tumor cells.

The RNA sensor RIG-I dually functions as an innate sensor and direct antiviral factor for hepatitis B virus.

Host innate recognition triggers key immune responses for viral elimination. The sensing mechanism of hepatitis B virus (HBV), a DNA virus, and the subsequent downstream signaling events remain to be fully clarified. Here we found that type III but not type I interferons are predominantly induced in human primary hepatocytes in response to HBV infection, through retinoic acid-inducible gene-I (RIG-I)-mediated sensing of the 5'-ε region of HBV pregenomic RNA. In addition, RIG-I could also counteract the interaction of HBV polymerase (P protein) with the 5'-ε region in an RNA-binding dependent manner, which consistently suppressed viral replication. Liposome-mediated delivery and vector-based expression of this ε region-derived RNA in liver abolished the HBV replication in human hepatocyte-chimeric mice. These findings identify an innate-recognition mechanism by which RIG-I dually functions as an HBV sensor activating innate signaling and to counteract viral polymerase in human hepatocytes.

Tumor-α9ß1 integrin-mediated signaling induces breast cancer growth and lymphatic metastasis via the recruitment of cancer-associated fibroblasts.

UNLABELLED: Tumor-derived matricellular proteins such as osteopontin (OPN) and tenascin-C (TN-C) have been implicated in tumor growth and metastasis. However, the molecular basis of how these proteins contribute to tumor progression remains to be elucidated. Importantly, these matricellular proteins are known to interact with α9ß1 integrin. Therefore, we hypothesized that tumor-derived α9ß1 integrin may contribute to tumor progression. To clarify the roles of α9ß1 integrin in tumor growth and lymphatic metastasis, we used an inhibitory anti-human α9ß1 integrin antibody (anti-hα9ß1 antibody) and a α9ß1 integrin-positive human breast cancer cell line, MDA-MB-231 luc-D3H2LN (D3H2LN), in vitro functional assays, and an in vivo orthotopic xenotransplantation model. In this study, we demonstrated that tumor, but not host α9ß1 integrin, contributes to tumor growth, lymphatic metastasis, recruitment of cancer-associated fibroblasts (CAFs), and host-derived OPN production. We also found that CAFs contributed to tumor growth, lymphatic metastasis, and host-derived OPN levels. Consistent with those findings, tumor volume was well-correlated with numbers of CAFs and levels of host-derived OPN. Furthermore, it was shown that the inoculation of D3H2LN cells into mammary fat pads with mouse embryonic fibroblasts (MEFs), obtained from wild type, but not OPN knock-out mice, resulted in enhancement of tumor growth, thus indicating that CAF-derived OPN enhanced tumor growth. These results suggested that tumor α9ß1-mediated signaling plays a pivotal role in generating unique primary tumor tissue microenvironments, which favor lymphatic metastasis and tumor growth. KEY MESSAGES: Tumor α9ß1 integrin promotes lymphatic metastasis through enhancing invasion. Tumor α9ß1 integrin promotes tumor growth through CAFs. Tumor α9ß1 integrin enhances the recruitment of CAFs into the primary tumor. Tumor cells induce the production of OPN by CAFs in the primary tumor. CAF-derived OPN promotes tumor growth.

Tumor-infiltrating DCs suppress nucleic acid-mediated innate immune responses through interactions between the receptor TIM-3 and the alarmin HMGB1.

The mechanisms by which tumor microenvironments modulate nucleic acid-mediated innate immunity remain unknown. Here we identify the receptor TIM-3 as key in circumventing the stimulatory effects of nucleic acids in tumor immunity. Tumor-associated dendritic cells (DCs) in mouse tumors and patients with cancer had high expression of TIM-3. DC-derived TIM-3 suppressed innate immune responses through the recognition of nucleic acids by Toll-like receptors and cytosolic sensors via a galectin-9-independent mechanism. In contrast, TIM-3 interacted with the alarmin HMGB1 to interfere with the recruitment of nucleic acids into DC endosomes and attenuated the therapeutic efficacy of DNA vaccination and chemotherapy by diminishing the immunogenicity of nucleic acids released from dying tumor cells. Our findings define a mechanism whereby tumor microenvironments suppress antitumor immunity mediated by nucleic acids.

ATM-mediated DNA damage signals mediate immune escape through integrin-αvß3-dependent mechanisms.

Although the tumor microenvironment plays a critical role in tumor progression and metastasis, the relationship between chemotherapy resistance and modulation of the tumor microenvironment remains unclear. Here, we report a novel mechanism showing how constitutive DNA damage signals in therapy-resistant tumor cells suppress antitumor immunity in an integrin-αvß3-dependent manner. Integrin-αvß3 was upregulated on various therapy-resistant tumor cells through chronic activation of ATM/Chk2-and NFκB-mediated pathways. Inhibiting tumor-specific expression of integrin-αvß3 improved therapeutic responses to anticancer drugs by stimulating endogenous host immune systems. Mechanistic investigations revealed that tumor-specific integrin-αvß3 expression targeted dendritic cells, facilitating their ability to phagocytose viable therapy-resistant tumor cells and thereby impaired their ability to cross-prime antigen-specific T lymphocytes. Together, our results clarify the detrimental effects of constitutive DNA damage signals to chemosensitivity and antitumor immunity. Furthermore, these findings suggest that integrin-αvß3 targeting may benefit patients' refractory to current anticancer regimens by defeating DNA damage signaling-induced immune escape.

Tumor-associated macrophages regulate tumorigenicity and anticancer drug responses of cancer stem/initiating cells.

Recent evidence has unveiled the critical role of tumor cells with stem cell activities in tumorigenicity and drug resistance, but how tumor microenvironments regulate cancer stem/initiating cells (CSCs) remains unknown. We clarified the role of tumor-associated macrophages (TAMs) and their downstream factor milk-fat globule-epidermal growth factor-VIII (MFG-E8) in the regulation of CSC activities. Bone marrow chimeric systems and adoptive cell transfers elucidated the importance of MFG-E8 from TAMs in conferring to CSCs with the ability to promote tumorigenicity and anticancer drug resistance. MFG-E8 mainly activates signal transducer and activator of transcription-3 (Stat3) and Sonic Hedgehog pathways in CSCs and further amplifies their anticancer drug resistance in cooperation with IL-6. Thus, the pharmacological targeting of key factors derived from tumor-associated inflammation provides a unique strategy to eradicate therapy-resistant tumors by manipulating CSC activities.

Interferon-α/ß and anti-fibroblast growth factor receptor 1 monoclonal antibody suppress hepatic cancer cells in vitro and in vivo.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most commonly occurring primary liver cancer and ranks as the fifth most frequently occurring cancer, overall, and the third leading cause of cancer deaths, worldwide. At present, effective therapeutic options available for HCC are limited; consequently, the prognosis for these patients is poor. Our aim in the present study was to identify a novel target for antibody therapy against HCC. METHODOLOGY/PRINCIPAL FINDINGS: We used Western blot and flow cytometric and immunocytochemical analyses to investigate the regulation of FGFR1 expression by interferon-α/ß in several human hepatic cancer cell lines. In addition, we tested the efficacy of combined treatment with anti-FGFR1 monoclonal antibody and interferon-α/ß in a murine xenograft model of human HCC. We found that interferon-α/ß induces expression of FGFR1 in human HCC cell lines, and that an anti-FGFR1 monoclonal antibody (mAb) targeting of the induced FGFR1 can effectively inhibit growth and survival of HCC cells in vitro and in vivo. Moreover, the combination of interferon-α, anti-FGFR1 mAb and peripheral blood mononuclear cells (PBMCs) exerted a significant antitumor effect in vitro. CONCLUSIONS: Our results suggest that the combined use of an anti-FGFR1 antibody and interferon-α/ß is a promising approach to the treatment of HCC.

IRF3 regulates cardiac fibrosis but not hypertrophy in mice during angiotensin II-induced hypertension.

Hypertension is a typical modern lifestyle-related disease that is closely associated with the development of cardiovascular disorders. Elevation of angiotensin II (ANG II) is one of several critical factors for hypertension and heart failure; however, the mechanisms underlying the ANG II-mediated pathogenesis are still poorly understood. Here, we show that ANG II-mediated cardiac fibrosis, but not hypertrophy, is regulated by interferon regulatory factor 3 (IRF3), which until now has been exclusively studied in the innate immune system. In a ANG II-infusion mouse model (3.0 mg/kg/d), we compared IRF3-deficient mice (Irf3(-/-)/Bcl2l12(-/-)) with matched wild-type (WT) controls. The development of cardiac fibrosis [3.95 ± 0.62% (WT) vs. 1.41 ± 0.46% (Irf3(-/-)/Bcl2l12(-/-)); P<0.01] and accompanied reduction in left ventricle end-diastolic dimension [2.89 ± 0.10 mm (WT) vs. 3.51 ± 0.15 mm (Irf3(-/-)/Bcl2l12(-/-)); P=0.012] are strongly suppressed in Irf3(-/-)/Bcl2l12(-/-) mice, whereas hypertrophy still develops. Further, we provide evidence for the activation of IRF3 by ANG II signaling in mouse cardiac fibroblasts. Unlike the activation of IRF3 by innate immune receptors, IRF3 activation by ANG II is unique in that it is activated through the canonical ERK signaling pathway. Thus, our present study reveals a hitherto unrecognized function of IRF3 in cardiac remodeling, providing new insight into the progression of hypertension-induced cardiac pathogenesis.

ZAPS is a potent stimulator of signaling mediated by the RNA helicase RIG-I during antiviral responses.

The poly(ADP-ribose) polymerases (PARPs) participate in many biological and pathological processes. Here we report that the PARP-13 shorter isoform (ZAPS), rather than the full-length protein (ZAP), was selectively induced by 5'-triphosphate-modified RNA (3pRNA) and functioned as a potent stimulator of interferon responses in human cells mediated by the RNA helicase RIG-I. ZAPS associated with RIG-I to promote the oligomerization and ATPase activity of RIG-I, which led to robust activation of IRF3 and NF-κB transcription factors. Disruption of the gene encoding ZAPS resulted in impaired induction of interferon-α (IFN-α), IFN-ß and other cytokines after viral infection. These results indicate that ZAPS is a key regulator of RIG-I signaling during the innate antiviral immune response, which suggests its possible use as a therapeutic target for viral control.