Interferon-induced Transmembrane Protein 1 Expression Research Articles

HIV-1 inhibits IFITM3 expression to promote the infection of megakaryocytes.

Despite an undetectable plasma viral load as a result of antiretroviral therapy, HIV-1-infected individuals with poor immune reconstitution harbor infectious HIV-1 within their platelets. Megakaryocytes, as platelet precursors, are the likely cellular origin of these HIV-1-containing platelets. To investigate the mechanisms that allow megakaryocytes to support HIV-1 infection, we established in vitro models of viral infection using hematopoietic stem cell-derived megakaryocytes and the megakaryocytic MEG-01 cell line. We observed HIV-1 DNA provirus integration into the megakaryocyte cell genome, self-limiting virus production, and HIV-1 protein and RNA compartmentalization, which are hallmarks of HIV-1 infection in myeloid cells. In addition, following HIV-1 infection of megakaryocyte precursors, the expression of interferon-induced transmembrane protein 3 (IFITM3), an antiviral factor constitutively expressed in megakaryocytes, was inhibited in terminally differentiated HIV-1-infected megakaryocytes. IFITM3 knockdown in MEG-01 cells prior to infection led to enhanced HIV-1 infection, indicating that IFITM3 acts as an HIV-1 restriction factor in megakaryocytes. Together, these findings indicate that megakaryocyte precursors are susceptible to HIV-1 infection, leading to terminally differentiated megakaryocytes harboring virus in a process regulated by IFITM3. Megakaryocytes may thus constitute a neglected HIV-1 reservoir that warrants further study in order to develop improved antiretroviral therapies and to facilitate HIV-1 eradication.

Interferon-Induced Transmembrane Protein 1 (IFITM1) Is Downregulated in Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors.

Neurofibromatosis type 1 (NF1), an autosomal dominant genetic disorder, is caused by mutations in the NF1 gene, which encodes the GTPase-activating protein neurofibromin. The pathogenesis of the tumor progression of benign plexiform neurofibromas (PNs) and malignant peripheral nerve sheath tumors (MPNSTs) remain unclear. Here, we found that interferon-induced transmembrane protein 1 (IFITM1) was downregulated in MPNST tissues compared to those in PN tissues from patients with NF1. Overexpression of IFITM1 in NF1-associated MPNST cells resulted in a significant decrease in Ras activation (GTP-Ras) and downstream extracellular regulatory kinase 1/2 (ERK1/2) phosphorylation, whereas downregulation of IFITM1 via treatment with small interfering RNA in normal Schwann cells had the opposite result, indicating that expression levels of IFITM1 are closely associated with tumor progression in NF1. Treatment of MPNST cells with interferon-gamma (IFN-γ) significantly augmented the expression of IFITM1, thereby leading to a decrease in Ras and ERK1/2 activation. Despite the small number of patient samples, these findings may potentially provide a new target for chemotherapy in patients with NF1-associated MPNSTs. In xenograft mice injected with MPNST cells, IFN-γ treatment successfully suppressed tumor progression with increased IFITM1 expression and decreased Ras and ERK1/2 activation in tumor tissues. Collectively, these results suggest that IFITM1 is closely involved in MPNST pathogenesis and that IFN-γ is a good candidate for the therapeutic treatment of MPNSTs in NF1.

LPS-induced senescence of macrophages aggravates calcification and senescence of vascular smooth muscle cells via IFITM3

Background Cellular senescence, macrophages infiltration, and vascular smooth muscle cells (VSMCs) osteogenic transdifferentiation participate in the pathophysiology of vascular calcification in chronic kidney disease (CKD). Senescent macrophages are involved in the regulation of inflammation in pathological diseases. In addition, senescent cells spread senescence to neighboring cells via Interferon-induced transmembrane protein3 (IFITM3). However, the role of senescent macrophages and IFITM3 in VSMCs calcification remains unexplored. Aims To explore the hypothesis that senescent macrophages contribute to the calcification and senescence of VSMCs via IFITM3. Methods Here, the macrophage senescence model was established using Lipopolysaccharides (LPS). The VSMCs were subjected to supernatants from macrophages (MCFS) or LPS-induced macrophages (LPS-MCFS) in the presence or absence of calcifying media (CM). Senescence-associated β-galactosidase (SA-β-gal), Alizarin red (AR), immunofluorescent staining, and western blot were used to identify cell senescence and calcification. Results The expression of IFITM3 was significantly increased in LPS-induced macrophages and the supernatants. The VSMCs transdifferentiated into osteogenic phenotype, expressing higher osteogenic differentiation markers (RUNX2) and lower VSMCs constructive makers (SM22α) when cultured with senescent macrophages supernatants. Also, senescence markers (p16 and p21) in VSMCs were significantly increased by senescent macrophages supernatants treated. However, IFITM3 knockdown inhibited this process. Conclusions Our study showed that LPS-induced senescence of macrophages accelerated the calcification of VSMCs via IFITM3. These data provide a new perspective linking VC and aging, which may provide clues for diagnosing and treating accelerated vascular aging in patients with CKD.

Genome-wide CRISPR activation screen identifies JADE3 as an antiviral activator of NF-kB–dependent IFITM3 expression

The innate immune system features a web of interacting pathways that require exquisite regulation. To identify novel nodes in this immune landscape we conducted a gain of function, genome-wide CRISPR activation screen with influenza A virus. We identified both appreciated and novel antiviral genes, including JADE3 a protein involved in directing the histone acetyltransferase HBO1 complex to modify chromatin and regulate transcription. JADE3 is both necessary and sufficient to restrict influenza A virus infection. Our results suggest a distinct function for JADE3 as expression of the closely related paralogues JADE1 and JADE2 does not confer resistance to influenza A virus infection. JADE3 is required for both constitutive and inducible expression of the well characterized antiviral gene Interferon-Induced Transmembrane Protein 3 (IFITM3). Furthermore, we find JADE3 activates the NF-kB signaling pathway, which is required for the promotion of IFITM3 expression by JADE3. Therefore, we propose JADE3 activates an antiviral genetic program involving NF-kB dependent IFITM3 expression to restrict influenza A virus infection.

Proteomic detection of COX-2 pathway-related factors in patients with adenomyosis.

Investigating the relationship between cyclooxygenase-2 (COX-2) pathway-related factors and clinical features in patients with adenomyosis by proteomics could provide potential therapeutic targets. This study recruited 40 patients undergoing surgical hysterectomy and pathological diagnosis of adenomyosis, collected ectopic endometrial specimens, and recorded clinical data. The expression levels of COX-2 in ectopic uterus lesions were detected using the immunohistochemical (IHC) SP method. The 40 samples were then divided into a COX-2 low or high expression group. Five samples with the most typical expression levels were selected from each of the two groups and the differential proteins between the two groups were identified using label-free quantitative proteomics. WW domain-binding protein 2 (WBP2), interferon induced transmembrane protein 3 (IFITM3), and secreted frizzled-related protein 4 (SFRP4) were selected for further verification, and their relationships with COX-2 and clinical characteristics were analyzed. There were statistically significant differences in the expression of WBP2, IFITM3, and SFRP4 between the COX-2 low and high expression groups (P < 0.01). The expressions of COX-2, IFITM3, and SFRP4 were significantly correlated with dysmenorrhea between the two groups (P < 0.05), but not with uterine size or menstrual volume (P > 0.05). However, there was no significant correlation between the expression of WBP2 and dysmenorrhea, uterine size, and menstruation volume in both the high expression and low expression groups (P > 0.05). COX-2, IFITM3, SFRP4, and WBP2 may be involved in the pathogenesis of adenomyosis. COX-2, IFITM3, and SFRP4 may serve as potential molecular biomarkers or therapeutic targets in dysmenorrhea in patients with early adenomyosis.

IFITM3 promotes glioblastoma stem cell-mediated angiogenesis via regulating JAK/STAT3/bFGF signaling pathway

Interferon-induced transmembrane protein 3 (IFITM3) has been previously verified to be an endosomal protein that prevents viral infection. Recent findings suggested IFITM3 as a key factor in tumor invasion and progression. To clarify the role and molecular mechanism of IFITM3 in Glioblastoma multiforme (GBM) progression, we investigated the expression of IFITM3 in glioma datasets culled from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA). Primary GBM stem cells (GSCs) were cultured and identified in vitro. Loss-of-function and gain-of-function experiments were established by using shRNAs and lentiviral vectors targeting IFITM3. Co-culture system of GSCs and vascular endothelial cells was constructed in a Transwell chamber. Tube formation and spheroid-based angiogenesis assays were performed to determine the angiogenic capacity of endothelial cells. Results revealed that IFITM3 is elevated in GBM samples and predictive of adverse outcome. Mechanistically, GSCs-derived IFITM3 causes activation of Jak2/STAT3 signaling and leads to robust secretion of bFGF into tumor environment, which eventually results in enhanced angiogenesis. Taken together, these evidence indicated IFITM3 as an essential factor in GBM angiogenesis. Our findings provide a new insight into mechanism by which IFITM3 modulates GBM angiogenesis.

Evaluation of long non-coding RNAs EGOT, NRAV, NRIR and mRNAs ISG15 and IFITM3 expressions in COVID-19 patients

Individuals with Coronavirus Disease 2019 (COVID-19) may show no symptoms to moderate or severe complications. This variation may be due to differences in the strength of the immune response, including a delayed interferon (IFN) response in asymptomatic patients and higher IFN levels in severe patients. Some long non-coding RNAs (lncRNAs), as regulators of the IFN pathway, may contribute to the emergence of different COVID-19 symptoms. This study aimed to comparatively investigate the relationship between lncRNAs (eosinophil granule ontogeny transcript (EGOT), negative regulator of antiviral response (NRAV), and negative regulator of interferon response (NRIR)), alongside interferon-stimulated genes (ISGs) like ISG-15 and interferon-induced transmembrane protein 3 (IFITM3) in COVID-19 patients with asymptomatic, moderate, and severe symptoms. Buffy coat samples were collected from 17 asymptomatic, 23 moderate, 22 severe patients, and 44 healthy controls. Quantitative real-time PCR was utilized to determine the expression levels. In a comparison between COVID-19 patients and healthy individuals, higher expression levels of EGOT and NRAV were observed in severe and moderate patients. NRIR expression was increased across all patient groups. Meanwhile, ISG15 expression decreased in all patient groups, and the moderate group showed a significant decrease in IFITM3 expression. Comparing COVID-19 patient groups, EGOT expression was significantly higher in moderate COVID-19 patients compared to asymptomatic patients. NRAV was higher in moderate and severe patients compared to asymptomatic. NRIR levels did not differ significantly between the COVID-19 patient groups. ISG15 was higher in moderate and severe patients compared to asymptomatic. IFITM3 expression was significantly higher in severe patients compared to the moderate group. In severe COVID-19 patients, EGOT expression was positively correlated with NRAV levels. EGOT and NRAV showed a significant positive correlation in asymptomatic patients, and both were positively correlated with IFITM3 expression. This study suggests that EGOT, NRAV, NRIR, ISG15, and IFITM3 may serve as diagnostic biomarkers for COVID-19. The lncRNA NRAV may be a good biomarker in a prognostic panel between asymptomatic and severe patients in combination with other high-sensitivity biomarkers. EGOT, NRAV, and ISG15 could also be considered as specific biomarkers in a prognostic panel comparing asymptomatic and moderate patients with other high-sensitivity biomarkers.

HSV1-induced enhancement of productive HIV-1 replication is associated with interferon pathway downregulation in human macrophages.

Herpesviruses are common co-pathogens in individuals infected with human immunodeficiency virus (HIV). Herpes simplex virus type 1 (HSV1) enhances HIV-1 replication and has evolved mechanisms to evade or disrupt host innate immune responses, including interference with interferon (IFN) signalling pathways. The aimed of this work was evaluated whether it HSV1 affects HIV-1 replication through the modulation of the IFN pathway in human macrophages. Co-infections with HSV1 and HIV-1 were performed in monocyte-derived human macrophages (hMDMs). The production of infectious HIV-1 and HSV-1 was monitored 48 h post-coinfection. Additionally, mRNA and protein expression levels of interferon-stimulated genes (ISGs) were evaluated in both HIV-1-HSV1 coinfections and HSV1 mono-infections. The HSV1 coinfection increasing the HIV-1 productive replication, following of downregulation of interferon-alpha (IFN-α) and interferon-induced transmembrane protein 3 (IFITM3) expression in hMDMs. Acyclovir treatment, in a dose-dependent manner, mitigated HSV1's ability to decrease IFITM3 levels. Knockdown of HSV1 Us11 and virion host shutoff (VHS) genes reactivated the IFN pathway, evidenced by restored IFITM3 expression and activation of eIF2-α and PKR. This knockdown also returned HIV-1 replication to baseline levels. Our data suggested that HSV1 increases HIV-1 replication in human macrophages is associated with the downregulating interferon pathways and ISGs expression.

Oncostatin M Induces IFITM1 Expression to Inhibit Hepatitis B Virus Replication Via JAK-STAT Signaling

Functional cure is achieved by a limited number of patients with chronic hepatitis B (CHB) after nucleotide analogue(s) and interferon treatment. It is urgent to develop therapies that can help a larger proportion of patients achieve functional cure. The present study was designed to explore the anti-hepatitis B virus (HBV) potency of interleukin-6 family cytokines and to characterize the underlying mechanisms of the cytokine displaying the highest anti-HBV potency. HBV-infected cells were used to screened the anti-HBV potency of interleukin-6 family cytokines. The concentration of oncostatin M (OSM) in patients with chronic HBV infection was examined by enzyme-linked immunosorbent assay. The underlying mechanism of OSM anti-HBV was explored through RNA-seq. C57BL/6 mice injected with rAAV8-1.3HBV were used to explore the suppression effect of OSM on HBV invivo. OSM is the most effective of the interleukin-6 family cytokines for suppression of HBV replication (percentage of average inhibition: hepatitis B surface antigen, 34.44%; hepatitis B e antigen, 32.52%; HBV DNA, 61.57%). Hepatitis B e antigen-positive CHB patients with high OSM levels had lower hepatitis B surface antigen and hepatitis B e antigen than those with low levels. OSM activated JAK-STAT signaling pathway promoting the formation of STAT1-IRF9 transcription factor complex. Following this, OSM increased the expression of various genes with known functions in innate and adaptive immunity, which was higher expression in patients with CHB in immune clearance phase than in immune tolerance phase (data from GEO: GSE65359). Interferon-induced transmembrane protein 1, one of the most differentially expressed genes, was identified as an HBV restriction factor involved in OSM-mediated anti-HBV effect. Invivo, we also found OSM significantly inhibited HBV replication and induced expression of antiviral effector interferon-induced transmembrane protein1. Our study shows that OSM remodels the immune response against HBV and exerts potent anti-HBV activity, supporting its further development as a potential therapy for treating CHB.

MicroRNA-363-3p inhibits colorectal cancer progression by targeting interferon-induced transmembrane protein 1.

The molecular mechanisms of colorectal cancer development and progression are far from being elucidated. To investigate the role of microRNA-363-3p (miR-363-3p) in the progression of colorectal cancer. Real-time polymerase chain reaction was performed to detect miRNA expression in human colorectal cancer tissues and paired normal colorectal tissues. PITA 6 was utilized to predict the targets of miR-363-3p. Dual-luciferase reporter system was used to validate the target of miR-363-3p. Plate colony formation assay and wound-healing assay were performed to evaluate cancer cells' clonogenic survival ability and migration ability, respectively. Cell proliferation was examined by cell counting kit-8 assay. Immunohistochemical staining was used to determine the expression level of interferon-induced transmembrane protein 1 (IFITM1) in colorectal cancer tissues and adjacent tissues. The TCGA and GTEx databases were used to compare the expression levels of IFITM1 mRNA in colorectal cancer tissues and normal colorectal tissues and analyze the correlation between the expression levels of IFITM1 mRNA and overall survival and disease-free survival of patients. A colorectal cancer cell line with a deficiency of IFITM1 was constructed, and the regulation effect of IFITM1 on the clonogenic growth of colorectal cancer cells was clarified. MiR-363-3p was decreased in colorectal cancer tissues compared to normal colorectal tissues. IFITM1 was characterized as a direct target of miR-363-3p. Overexpression of miR-363-3p led to decreased clonogenic survival, proliferation, and migration of colorectal cancer cells, which could be reversed by forced IFITM1 expression. MiR-363-3p can constrain clonogenic survival, proliferation, and migration of colorectal cancer cells via targeting IFITM1.

Interferon-induced transmembrane protein 3 in the hippocampus: a potential novel target for the therapeutic effects of recombinant human brain natriuretic peptide on sepsis-associated encephalopathy.

This study aims to explore whether interferon-induced transmembrane protein 3 (IFITM3) is involved in recombinant human brain natriuretic peptide (rhBNP)-mediated effects on sepsis-induced cognitive dysfunction in mice. The cellular localization and expression level of IFITM3 in the hippocampus were detected. The IFITM3 overexpression was achieved using an intracranial stereotactic system to inject an adeno-associated virus into the hippocampal CA1 region of mice. Field experiments, an elevated plus maze, and conditioned fear memory tests assessed the cognitive impairment in rhBNP-treated septic mice. Finally, in the hippocampus of septic mice, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining and Immunoblot were used to detect changes in the protein expression of cleaved Caspase-8 and cleaved Caspase-3 in apoptosis-related pathways, and toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) p65 in inflammatory pathways. Fourteen days after cecal ligation and puncture (CLP) surgery, IFITM3 localized in the plasma membrane and cytoplasm of the astrocytes in the hippocampus of septic mice, partially attached to the perivascular and neuronal surfaces, but not expressed in the microglia. The expression of IFITM3 was increased in the astrocytes and neurons in the hippocampus of septic mice, which was selectively inhibited by the administration of rhBNP. Overexpression of IFITM3 resulted in elevated anxiety levels and long-term learning and memory dysfunction, completely abolished the therapeutic effect of rhBNP on cognitive impairment in septic mice, and induced an increase in the number of neuronal apoptosis in the hippocampal CA1 region. The expression levels of cleaved Caspase-3 and cleaved Caspase-8 proteins were significantly increased in the hippocampus, but the expression levels of TLR4 and NF-κB p65 were not increased. The activation of IFITM3 may be a potential new target for treating sepsis-associated encephalopathy (SAE), and it may be one of the key anti-apoptotic mechanisms in rhBNP exerting its therapeutic effect, providing new insight into the clinical treatment of SAE patients.

Interferon-induced transmembrane protein 3 in hepatocellular carcinoma patients

ObjectiveThe study aimed to investigate the over expression of IFITM3 in hepatocellular carcinoma Egyptian patients.BackgroundHepatocellular carcinoma (HCC) continues to be a serious disease burden. Interferon Induced Transmembrane protein 3 (IFITM3) is a protein that encoded in humans by the IFITM3 gene. It plays a critical role in the immune system’s defense, responsible for a large portion of the antiviral activity. In this study, we showed that IFITM3 rs 12252-CC was over expressed in HCC patients compared to control group with HCV infection.MethodDNA sequencing was applied for detection of IFITM3 rs 12252-CC and IFITM3 protein level was measured by ELISA to 50 patients with HCC with cirrhosis and 50 with Hepatitis C virus infection.ResultsThe obtained results of this study indicated that IFITM3 rs 12252-CC was significantly elevated in HCC group, the codominant model of CC genotype of IFITM3 gene had high association with risk of hepatocellular carcinoma with odd ratio (OR) = 2.70, p = 0.041.ConclusionIFITM3 play an important role in progression of hepatocellular carcinoma. Results revealed that IFITM3 rs 12252-CC among Hepatocellular carcinoma patients would allow diagnosis and starting intervention.

Ethyl Gallate Inhibits Bovine Viral Diarrhea Virus by Promoting IFITM3 Expression, Lysosomal Acidification and Protease Activity.

Bovine viral diarrhea virus (BVDV) is a highly contagious viral disease which causes economic losses to the cattle industry. Ethyl gallate (EG) is a phenolic acid derivative which has various potentials to modulate the host response to pathogens, such as via antioxidant activity, antibacterial activity, inhibition of the production of cell adhesion factors, and so on. This study aimed to evaluate if EG influences BVDV infection in Madin-Darby Bovine Kidney (MDBK) cells, and to understand the antiviral mechanism. Data indicated that EG effectively inhibited BVDV infection by co-treatment and post-treatment in MDBK cells with noncytotoxic doses. In addition, EG suppressed BVDV infection at an early stage of the viral life cycle by blocking entry and replication steps but not viral attachment and release. Moreover, EG strongly inhibited BVDV infection by promoting interferon-induced transmembrane protein 3 (IFITM3) expression, which localized to the cytoplasm. The protein level of cathepsin B was significantly reduced by BVDV infection, whereas with treatment with EG, it was significantly enhanced. The fluorescence intensities of acridine orange (AO) staining were significantly decreased in BVDV-infected cells but increased in EG-treated cells. Finally, Western blot and immunofluorescence analyses demonstrated that EG treatment significantly enhanced the protein levels of autophagy markers LC3 and p62. Chloroquine (CQ) significantly increased IFITM3 expression, and Rapamycin significantly decreased it. Thus, EG may regulate IFITM3 expression through autophagy. Our results showed that EG could have a solid antiviral activity on BVDV replication in MDBK cells via increased IFITM3 expression, lysosomal acidification, protease activity, and regulated autophagy. EG might have value for further development as an antiviral agent.

ROS-responsive nanomodulators downregulate IFITM3 expression and eliminate ROS for Alzheimer’s disease combination treatment

Neuronal damage caused by β-amyloid (Aβ) aggregates and excess reactive oxygen species (ROS) is a crucial pathogenic event in Alzheimer's disease (AD). However, current Aβ-targeting RNA interference (RNAi) treatments have shown limited therapeutic efficacy due to ineffective intracerebral siRNA delivery and overlooked crosstalk between excess ROS and Aβ aggregates in the brain. Herein, a ROS-responsive nanomodulator (NM/CM) was developed for the combinational treatment of RNAi and ROS elimination for AD. NM/CM was coated with 4T1 cell membranes, which endowed NM/CM with the capability to cross blood–brain barrier (BBB). After being internalized by neural cells, NM/CM releases curcumin (Cur) and siIFITM3 spontaneously into the cytoplasm. The released Cur can eliminate ROS, protecting neurons from oxidative damage and reducing the production of Aβ induced by ROS-related neuroinflammation. The released siIFITM3 can downregulate the expression of interferon-induced transmembrane protein 3 (IFITM3), thereby reducing the abnormal Aβ production mediated by IFITM3. As a result, NM/CM remarkably alleviated ROS- and Aβ aggregate-induced neurotoxicity in vitro, showing significant neuroprotective effects. This work demonstrates the potential of NM/CM in the development of novel and effective AD combination therapies.

Immune surveillance of brain metastatic cancer cells is mediated by IFITM1.

Brain metastasis, most commonly originating from lung cancer, increases cancer morbidity and mortality. Although metastatic colonization is the rate-limiting and most complex step of the metastatic cascade, the underlying mechanisms are poorly understood. Here, in vivo genome-wide CRISPR-Cas9 screening revealed that loss of interferon-induced transmembrane protein 1 (IFITM1) promotes brain colonization of human lung cancer cells. Incipient brain metastatic cancer cells with high expression of IFITM1 secrete microglia-activating complement component 3 and enhance the cytolytic activity of CD8+ T cells by increasing the expression and membrane localization of major histocompatibility complex class I. After activation, microglia (of the innate immune system) and cytotoxic CD8+ T lymphocytes (of the adaptive immune system) were found to jointly eliminate cancer cells by releasing interferon-gamma and inducing phagocytosis and T-cell-mediated killing. In human cancer clinical trials, immune checkpoint blockade therapy response was significantly correlated with IFITM1 expression, and IFITM1 enhanced the brain metastasis suppression efficacy of PD-1 blockade in mice. Our results exemplify a novel mechanism through which metastatic cancer cells overcome the innate and adaptive immune responses to colonize the brain, and suggest that a combination therapy increasing IFITM1 expression in metastatic cells with PD-1 blockade may be a promising strategy to reduce metastasis.

ACE2 Affects the Expression and Function of IFITM3 During SARS-CoV-2 Pseudovirus Infection in Vero E6 Cells.

COVID-19 is a globally infectious viral epidemic of great public health concern caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Angiotensin-converting enzyme 2 (ACE2) plays its role as the receptor for SARS-CoV-2 through binding with S protein and the binding results in ACE2 expression decrease. The change of ACE2 is supposed to elicit a series of cellular and molecular events. Other than as the receptor, ACE2's roles on infection by regulating other molecules need to be further studied during SARS-CoV-2 infection. In the present study, we established the ACE2 knockdown model using Vero E6 cells to study how ACE2 influenced the downstream signaling molecules. Analysis of transcriptome sequencing discovered that ACE2 alteration per se caused the alteration of immune factors, including some related to the viral infection-related signaling pathways. We found that ACE2 silencing induced the reduced interferon-induced transmembrane protein 3 (IFITM3) expression. Overexpression of IFITM3 promoted the SARS-CoV-2 pseudovirus infection of Vero E6 cells lacking the ACE2. It indicates that ACE2 can affect IFITM3 expression and function to affect the SARS-CoV-2 infection. Our results reveal possible mechanisms influencing SARS-CoV-2 infectivity and contribute to explaining the rapid spread and pathogenesis especially in the case of ACE2 low expression.

MiR-504-3p Has Tumor-Suppressing Activity and Decreases IFITM1 Expression in Non-Small Cell Lung Cancer Cells.

Objective: To analyze the impact of expression of miR-504-3p on the proliferation, migration, cell cycle transit and rate of apoptosis of NSCLC cells and explore the underlying mechanisms. Methods: The Cancer Genome Atlas (TCGA) database was used to compare the expression levels of miR-504 between NSCLC tissues and normal lung tissues. NSCLC cells were transfected with lentiviral vectors that either overexpressed or knocked down miR-504-3p to evaluate its effects on NSCLC biological behavior. Quantitative Real Time Polymerase Chain Reaction was used to measure the levels of miR-504-3p and Interferon-Induced Transmembrane Protein 1 (IFITM1). A luciferase reporter array was used to reveal whether miR-504-3p directly targets IFITM1. Results: The expression of miR-504 was significantly down-regulated in lung cancer tissues compared to normal lung tissues. Overexpression of miR-504-3p in NSCLC cell lines inhibited cell proliferation, migration and promoted cell apoptosis. Meanwhile, changes in the expression level of miR-504-3p had no significant effect on NSCLC cell cycle progression. Moreover, over-expressed miR-504-3p following its transfection significantly decreased the expression of IFITM1 in NSCLC cell lines and suppressed the activity of the luciferase reporter containing wild type but not mutant IFITM1 3' -UTR. Conclusion: miR-504-3p inhibits cell proliferation and migration and promotes cell apoptosis in NSCLC cells. MiR-504-3p decreases IFITM1 expression in NSCLC cells, which may be a potential mechanism of its tumor-suppressive functions in NSCLC.

アルツハイマー病モデルマウスにおける脳内IFITM3の発現変化

アルツハイマー病モデルマウスにおける脳内IFITM3の発現変化

Enhanced IFNα Signaling Promotes Ligand-Independent Activation of ERα to Promote Aromatase Inhibitor Resistance in Breast Cancer.

Simple SummaryInterferon alpha (IFNα) signaling is highly upregulated in ER+ breast cancers that become resistant to estrogen deprivation therapy. This study uncovers how enhanced (IFNα)/JAK-STAT signaling directly influences estrogen receptor (ERα) activation in the absence of estrogen. We found that inhibiting IFNα signaling downregulates expression and activation of ERα. In addition, STAT1 and ERα directly interact and regulate a key interferon-stimulated gene, IFITM1, in AI-resistant breast cancer cells. We demonstrate that crosstalk occurs between IFNα and ERα pathways, which contributes to aggression and survival of AI-resistant breast cancer, thus representing a novel mechanism of acquired AI resistance.Aromatase inhibitors (AIs) reduce estrogen levels up to 98% as the standard practice to treat postmenopausal women with estrogen receptor-positive (ER+) breast cancer. However, approximately 30% of ER+ breast cancers develop resistance to treatment. Enhanced interferon-alpha (IFNα) signaling is upregulated in breast cancers resistant to AIs, which drives expression of a key regulator of survival, interferon-induced transmembrane protein 1 (IFITM1). However, how upregulated IFNα signaling mediates AI resistance is unknown. In this study, we utilized MCF-7:5C cells, a breast cancer cell model of AI resistance, and demonstrate that these cells exhibit enhanced IFNα signaling and ligand-independent activation of the estrogen receptor (ERα). Experiments demonstrated that STAT1, the mediator of intracellular signaling for IFNα, can interact directly with ERα. Notably, inhibition of IFNα signaling significantly reduced ERα protein expression and ER-regulated genes. In addition, loss of ERα suppressed IFITM1 expression, which was associated with cell death. Notably, chromatin immunoprecipitation experiments validated that both ERα and STAT1 associate with ERE sequences in the IFITM1 promoter. Overall, hyperactivation of IFNα signaling enhances ligand-independent activation of ERα, which promotes ER-regulated, and interferon stimulated gene expression to promote survival in AI-resistant breast cancer cells.

Interferon-Induced Transmembrane Protein 3 Shapes an Inflamed Tumor Microenvironment and Identifies Immuno-Hot Tumors.

Interferon-induced transmembrane protein 3 (IFITM3) is an interferon-induced membrane protein, which has been identified as a functional gene in multiple human cancers. The role of IFITM3 in cancer has been preliminarily summarized, but its relationship to antitumor immunity is still unclear. A pancancer analysis was conducted to investigate the expression pattern and immunological role of IFITM3 based on transcriptomic data downloaded from The Cancer Genome Atlas (TCGA) database. Next, correlations between IFITM3 and immunological features in the bladder cancer (BLCA) tumor microenvironment (TME) were assessed. In addition, the role of IFITM3 in estimating the clinical characteristics and the response to various therapies in BLCA was also evaluated. These results were next confirmed in the IMvigor210 cohort and a recruited cohort. In addition, correlations between IFITM3 and emerging immunobiomarkers, such as microbiota and N6-methyladenosine (m6A) genes, were assessed. IFITM3 was enhanced in most tumor tissues in comparison with adjacent tissues. IFITM3 was positively correlated with immunomodulators, tumor-infiltrating immune cells (TIICs), cancer immunity cycles, and inhibitory immune checkpoints. In addition, IFITM3 was associated with an inflamed phenotype and several established molecular subtypes. IFITM3 expression also predicted a notably higher response to chemotherapy, anti-EGFR therapy, and immunotherapy but a low response to anti-ERBB2, anti-ERBB4, and antiangiogenic therapy. In addition, IFITM3 was correlated with immune-related microbiota and m6A genes. In addition to BLCA, IFITM3 is expected to be a marker of high immunogenicity in most human cancers. In conclusion, IFITM3 expression can be used to identify immuno-hot tumors in most cancers, and IFITM3 may be a promising pancancer biomarker to estimate the immunological features of tumors.