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Background and objectives: SARS-C0V-2 infections have varied manifestations among individuals ranging from asymptomatic or mild symptoms to severe disease and death. This study is done to look into various histopathological changes in lung, liver, and kidney tissues among Covid19 positive autopsies with cellular tropism and viral load among various organs by immunohistochemistry (IHC) for the SARS-C0V-2 viral marker. Method(s): A prospective descriptive study of core biopsies from covid19 positive autopsies from the lung, liver, and kidneys were taken from 20 cases. A routine histopathological examination of the tissues with IHC staining for SARS-CoV-2 cocktail antibodies was performed and assessed. Result(s): Histopathological changes in the lung, liver, and kidney tissues showed changes of varying severity. On IHC, in the lung, the tropism for SARS-CoV-2 was seen in pneumocytes, bronchial epithelial cells, endothelial cells, and macrophages. In the kidney, tropism was seen towards tubular epithelial cells and endothelial cells. In the liver, hepatocytes and bile duct epithelial cells were positive. Variable viral density was seen in different organs which varied from case to case. The density of the viral load was highest in the lung and lower in the kidney and least in the liver. Conclusion(s): In this study the various histopathological changes and cellular tropism of the SARS-CoV-2 among Lung, liver, and kidney tissues have been described and compared with various similar studies across the globe.Copyright © 2023 International Journal of Life Sciences Biotechnology and Pharma Research. All rights reserved.
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As hyperbaric oxygen (HBO) has been shown to mitigate the COVID-19 symptoms, we were interested in studying whether HBO exposure affects expression of viral entry genes and innate immune genes in the air-liquid interface (ALI)-cultured human bronchial epithelial cells (HBECs) derived from normal individuals (NHBECs) and age-matched COPD patients (DHBECs), which were cultured under normoxia or daily exposure of 40-min hyperbaric oxygen (HBO) with 100% O2 at 2.5 ATA for 28 days in total. We found for the first time that HBO exposure differentially regulated mucociliary differentiation of HBECs by respectively decreasing and increasing expression of CGRP, MUC5AC, FOXJ1, NOTCH3 and HEYL in NHBECs and DHBECs, and respectively decreased and increased FOXO1 expression whereas increased and decreased NFE2L2 and NFKB1 expression in NHBECs and DHBECs, in association with respectively decreased and increased expression the SARS-CoV-2 entry genes ACE2 and 2 TMPRSS2 and the tight junction protein genes TJP1 and TJP2, and in association with respectively increased and decreased expression of the cell growth and inflammatory transcription factors SRF, c-FOS and TP63, as well as the TLR pathway genes TLR3, AKT1, IL-1B, IL-5, IL-6, IL-33, IRAK4 and NFKBIA in NHBECs and DHBECs. (Figure Presented).
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Even after virus elimination, coronavirus disease 2019 (COVID-2019) leaves numerous sequelae. Growing evidence demonstrates that massive release of proinflammatory cytokines, which drives COVID-19 progression, severity, and mortality, remains elevated after acute phase of COVID-2019, playing a central role in the disease' sequelae. In this way, bronchial epithelial cells are the first cells hyperactivated by coronavirus-2 (SARS-Cov-2) leading to massive cytokine release, triggering leukocytes and other cells hyperactivation, mediating COVID-19 sequelae. So, proinflammatory cytokines are initiated by the host. Thus, this in vitro study tested the hypothesis that ImmuneRecovTM, a protein blend, could inhibit the hyperactivation of human bronchial epithelial cells (BEAS-2B) induced by SARS-Cov-2. BEAS-2B (5x104/mL/well) cells were co-cultivated with 1ml of blood of a SARS-Cov-2 infected patient for 4 hours and protein blend (1ug/mL) was added in the first minute of the co-culture. After 4 hours, the cells were recovered and used for analysis of cytotoxicity by MTT and for mRNA expression of IL-1beta, IL-6, IL-10. The supernatant was used to measure cytokines. SARS-Cov-2 incubation resulted in increased levels of IL-1beta and IL-6 by BEAS-2B cells (p<0.001). Treatment with the protein blend resulted in reduced levels of pro-inflammatory IL1beta and IL-6 (p<0.001), and increased the levels of anti-inflammatory IL-10 (p<0.001). Protein blend reduced SARS Cov-2-increased the mRNA expression of IL-1beta and IL-6, and increased the expression of IL-10 and IFN-gamma. In conclusion, protein blend presents important anti-inflammatory effects in the context of SARS-Cov-2 infection.
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Background: TGF-beta signaling plays an essential role in tissue fibrosis and mediates profibrotic programs after SARS-CoV-2 infection in the kidney and lung. SARS-CoV-2 also induces humoral immune responses controlled by cytokines, including TGF-beta. Studies have found that the incidence of SARS-CoV-2 infection and the severity of Covid-19 in cystic fibrosis (CF) patients is lower than the general population. We studied how SARS-CoV-2 regulates TGF-beta-mediated gene expression in the CF airway. Method(s): Small RNAseq was performed in human bronchial epithelial cells CFBE41o-from a patient homozygous for the F508del mutation in the CFTR gene on Illumina NextSeq 500's. Pathway analysis was done by Ingenuity Pathway Analysis (IPA) software (QIAGEN) and miRNet browser. IPA was used for analyzing coronavirus associated pathways affected by differentially regulated miRNAs. miRNAs predicted to target the coronavirus associated genes were collected from TargetScan Human release 7.2, miRmap, Diana-TarBase v.8, and miRBase bioinformatics tools. Anti-miRNA oligonucleotide miRCURY LNATM Power Inhibitors or control (Exiqon) were used. Cells expressing F508del or wild type CFTR were used to compare the results in CF and non-CF models. Findings were validated in primary human bronchial epithelial (HBE) cells. Result(s): Compared to vehicle control, TGF-beta1 dysregulated 48 miRNAs;38 and 19 pathways were uniquely affected by the upregulated and downregulated miRNAs, respectively. We found 43 miRNAs targeting 119 different mRNA of the proteins associated with coronavirus pathogenesis pathway and 21 miRNAs targeting 21 different mRNA of the proteins associated with coronavirus replication pathway. Two miRNAs upregulated by TGF-beta1 target the host receptor for SARS-CoV-2 invasion, angiotensin converting enzyme 2 (ACE2). We confirmed the results by qRT-PCR that TGF-beta1 increased expression of specific miRNAs targeting ACE2 mRNA. Upregulation of the miRNAs was followed by inhibition of ACE2 mRNA and protein levels and the effect was blocked by specific anti-miRNA oligonucleotides. The above results differed between the CF and non-CF cells. Conclusion(s): miRNAs may be important effectors of TGF-beta modulating SARSCoV-2 pathogenicity and replication in the CF airway. Ongoing studies focus on elucidating the mechanisms of SARS-CoV-2 invasion of kidney cells.
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Background: People with cystic fibrosis (PwCF) have chronic, pronounced respiratory damage and have been considered among those at highest risk for serious harm from SARS-CoV-2. Numerous clinical studies have reported that individuals with CF in North America and Europe, although highly susceptible to COVID-19, do not have mortality levels that exceed those of the general population. Method(s): To understand features that might influence lethality of COVID- 19 in PwCF, we tested potential relationships between CFTR and viral pathogenesis. As one approach to evaluate impact of CF transmembrane conductance regulator (CFTR) on COVID-19 severity, independent sets of blood samples fromvirally infected individualswere genotyped. Bloodwas obtained from 424 U.S. patients hospitalized with severe COVID-19 and a much larger European cohort of 7147 healthy individuals and 2587 individuals with severe COVID-19. Deoxyribonucleic acid in both studies was probed for the F508del variant. In other experiments, we investigated the possibility that lack of CFTR might alter viral binding and propagation. We used human bronchial epithelial cell (HBEC) monolayers from individuals without functional CFTR for this purpose. Finally, we examined effects of CF airway secretions and features such as viscosity, pH, and protease/anti-protease imbalance during SARS-CoV-2 infection. Result(s): We found no evidence of a relationship between deficient CFTR function (based on carrier status for the severe F508del defect) and clinical outcomes from COVID-19. In addition, viral propagation studies using airway epithelial monolayers (a model that reproduces many aspects of in vivo tissue biology) were not influenced by homozygous absence of CFTR. We show that levels of angiotensin converting enzyme-2 receptor messenger ribonucleic acid (mRNA) appear normal in CF primary epithelium, whereas transmembrane serine protease 2 mRNA is variable but lower ( p < 0.001) in a manner that correlates with viral infectivity (R2 = 0.76). Dependence of viral proliferation on features of CF mucosal fluid-including pH (viral replication optimum at pH 7-7.5), viscosity (diminished propagation in highly viscous apical media), and protease/ anti-protease imbalancewere identified as likely contributors to efficiency of SARS-CoV-2 replication and pathogenesis. Conclusion(s): These findings using patient data, CF and non-CF primary airway epithelia, and CF airway secretions fail to demonstrate a causal relationship between loss of CFTR and susceptibility to severe COVID-19. Notwithstanding the caveat that addition of virus in small buffer volumes disrupts airway surface liquid depth and composition, our findings also argue against a role for CFTR during acute infection of airway cells in vitro. On the other hand, chronic disruption of periciliary liquid, diminished pH, altered protease/anti-protease homeostasis, and increased fluid viscosity (sequelae that occur in CF lungs) were implicated as contributors to impaired SARS-CoV-2 propagation. Such studies provide a basis for future work to test relationships between CFTR and severity of COVID-19. Copyright © 2022, European Cystic Fibrosis Society. All rights reserved
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Background: Acute respiratory infection (ARI) is the leading infectious cause of pediatric death worldwide, comprising 15% of all deaths in children under 5 years old. Human metapneumovirus (HMPV) is a primary cause of ARI, and accounts for a major portion of ARI-related hospitalizations in infants and young children. Although nearly every person is infected with HMPV during early childhood, re-infections occur often, highlighting the difficulty in building long-term immunity. There are no approved vaccines or antiviral therapies. Early host responses to HMPV are poorly characterized, and further understanding could identify important antiviral pathways and potential therapeutic targets. Type I (IFN-α/β) and III interferons (IFN-λ) display antiviral activity against numerous respiratory viruses and are currently being investigated for therapeutic use in several respiratory infections including SARS-CoV-2. However, their roles in HMPV infection remain largely unknown. Our laboratory has previously shown that type I IFN is critical for HMPV pathogenesis, as loss of IFN-α/β signaling reduces lung inflammation and lessens HMPV disease severity in mice. Here, we describe distinct antiviral roles for type I and III IFNs during HMPV infection using an established mouse model. Methods: In vivo studies were conducted using mice lacking either the IFN-α/ β receptor (IFNAR-/-) or IFN-λ receptor (IFNLR-/-). Early immune responses to HMPV strains TN/94-49 and C2-202 were assessed by clinical disease scoring, plaque assay, Luminex immunoassay, and spectral cytometry of mouse lung samples. In vitro studies were performed using CMT 64-61 mouse bronchial epithelial cells. Responses to TN/94-49 and C2-202 were measured by qPCR, plaque assay, and Luminex immunoassay of cell lysates and supernatants. Results: IFNAR-/- mice exhibited lower clinical disease scores, reduced lung levels of inflammatory cytokines IL6, MIP-1α, and MCP-1, and decreased numbers of lung interstitial macrophages during HMPV infection, highlighting their critical role in HMPV immune-mediated pathogenesis. IFNLR-/- mice with intact IFNAR showed moderate clinical disease, higher lung levels of inflammatory cytokines IL-6, MCP-1, and IFN-γ, and increased lung interstitial macrophage recruitment. A reduction in HMPV disease was also recapitulated by IFNAR-neutralizing antibody treatment of IFNLR-/- mice. Interestingly, IFNLR-/- showed higher HMPV viral titers, while IFNAR-/- mice showed no differences or slightly lower viral titers, compared to wild-type mice. Moreover, IFN-λ pre-treatment of infected CMT 64-61 cells reduced HMPV viral titers and decreased supernatant levels of inflammatory cytokines IL-6, IL-1β, TNFα, and MCP-1. Conclusion: These findings suggest that type I IFN is necessary for HMPV pathogenesis, while type III IFN is critical for limiting HMPV replication in the lungs but does not contribute to HMPV inflammatory disease. This work uncovers key functional differences between type I and III IFNs during HMPV infection, an important feature of innate immune responses to HMPV that may be utilized to inform treatment.
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RATIONALE: Treatments for the coronavirus disease of 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), are urgently needed but remain limited. SARS-CoV-2 infects cells through the interactions of its spike (S) protein with ACE2 and TMPRSS2 on host cells. Multiple cells and organs are targeted, particularly airway epithelial cells. OM-85, a standardized lysate of human airway bacteria with strong immunomodulating properties and an impeccable safety profile, is widely used to prevent recurrent respiratory infections. Our finding that the airway administration of OM-85 inhibits Ace2 and Tmprss2 transcription in mouse lungs prompted us to investigate whether and how OM-85 may protect non-human primate and human epithelial cells against SARS-CoV-2 infection. METHODS: ACE2 and TMPRSS2 mRNA and protein expression, cell binding of SARS-CoV-2 S1 protein, cell entry of SARS-CoV-2 S protein-pseudotyped lentiviral particles, and SARS-CoV-2 cell infection were measured in kidney, lung and intestinal epithelial cell lines, primary human bronchial epithelial cells, and ACE2- transfected HEK293T cells treated with OM-85 in vitro. RESULTS: OM-85 significantly downregulated ACE2 and TMPRSS2 mRNA in epithelial cell lines and primary bronchial epithelial cells, and strongly inhibited SARS-CoV-2 S protein binding to, SARS-CoV-2 S proteinpseudotyped lentivirus entry into, and SARS-CoV-2 infection of epithelial cells. These effects of OM-85 appeared to depend on the downregulation of SARS-CoV-2 receptor expression. CONCLUSIONS: OM-85 inhibits SARS-CoV-2 epithelial cell infection in vitro by downregulating SARS-CoV-2 receptor expression. Further studies are warranted to assess whether OM-85 may prevent and/or reduce the severity of COVID-19.
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Rationale: Cell-penetrating peptides are able to cross membranes and deliver cargoes in a functional form. Our prior work identified a 12-amino acid, cardiac targeting peptide (APWHLSSQYSRT). Studies into its mechanism of transduction led to the identification of two lung targeting peptides (LTPs), S7A and R11A. Here we report on a) the comparative lung uptake of S7A versus R11A, b) complete biodistribution of R11A, c) show that cyclic versions are -100-fold more efficient than linear counterparts, d) uptake is via a non-endocytic pathway, and e) cyclic R11A's (cR11A) ability to deliver siRNA targeting structural proteins of SARS-CoV-2 and act as an anti-viral. Methods: Linear LTPs were synthesized with N-terminal labeled with Cyanine 5.5 (Cy5.5). Cyclic versions were synthesized with lysine added to the N-terminus, cyclized through a peptide bond, with a side NH-group labeled with Cy5.5. cR11A was conjugated to siRNA duplexes via a DTME linker. Wild-type, CD1 mice, were injected with S7A or R11A at 10, 5, and 1mg/Kg, peptides allowed to circulate for 15mins, mice euthanized, lung along with multiple other organs dissected and imaged using In Vivo Imaging Systems (IVIS, Perkin-Elmer) followed by confocal microscopy. CD1 mice were injected with R11A, 5mg/Kg, and euthanized at different time intervals for biodistribution studies. Endocytosis studies were done using serum-starved human bronchial epithelial cells (HBEC) incubated with fluorescently labeled transferrin and LTP-S7A or LTP- R11A. Lastly, anti-viral activity was tested in HBECs pre-treated with cR11A-siRNA followed by viral infection. Results: Mice injected with LTP-S7A or LTP-R11A showed robust uptake of the peptides by lung tissue, with R11A showing an increasingly favorable lung:liver ratio with decreasing dose. Lung uptake of R11A peaked at 120mins with complete dissipation of fluorescence by 24 hours. In Vitro studies in HBECs showed no co-localization of transferrin with LTPs, ruling out endocytosis as a mechanism of uptake. Comparison of linear versus cyclic peptides using FACS showed cyclic peptides had -100-fold increased transduction efficiency over their linear counterparts. cR11A conjugated to ant-spike, and anti-envelop proteins showed an anti-viral effect with EC90 of 0.6uM and 1.0μM, respectively. Conclusions: We have identified two novel lung-targeting peptides capable of acting as delivery vectors. Peak uptake of R11A occurred at 120mins. Furthermore, this uptake was not via endocytosis, and cyclic versions were -100-fold more efficiently taken up. Lastly, as proof of concept, we show cR11A acts as a vector and delivers siRNA to HBECs in a functional form, and act as anti-virals.
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Background: A novel coronavirus (SARS-CoV-2) has led to the worldwide spread of pandemic proportions and currently no effective therapy is available. The minor pulmonary surfactant lipids, palmitoyl-oleoyl-phosphatidylglycerol (POPG), and phosphatidylinositol (PI), are potent regulators of inflammatory processes, and are effective as anti-viral agents for multiple respiratory viruses including Respiratory syncytial virus (RSV), Influenza A virus (IAV) and Rhinoviruses (RVs). Objective: The primary objectives of this study are to determine whether POPG or PI are potent against SARS-CoV-2 in vitro, using human airway epithelial cells, and examine the potency of PI against SARS-CoV-2 in vivo, in a hamster model. Methods: We examined efficacies of POPG or PI against SARS-CoV-2 (USA WA/2020) in human bronchial epithelial cells, and nasal epithelial cells from healthy control subjects differentiated by ALI cultures. We quantified SARS-CoV-2 replication by quantitative plaque assays and qRT-PCR. We determined the potency of PI against SARS-CoV- 2 in golden Syrian hamster as in vivo model for SARS-CoV-2 infection. Results: We examined the efficacies of POPG and PI using primary human tracheal and nasal epithelial cells, differentiated in ALI culture. Cells were treated with POPG (10mg/ml) and PI (4mg/ml) added to apical media alone for 16hrs. Subsequently, cells were infected with SARS-CoV-2 at m.o.i = 0.02, for 48hrs, harvested for RNA extraction and qRT-PCR. SARS-CoV-2 replicated in tracheal cells with a 106-fold increase in mRNA. POPG and PI reduced viral mRNA expression by 70% and 85%, respectively (subject numbers n=3). In nasal epithelia, SARS-CoV-2 mRNA expression increased 105 -fold compared to sham infected cultures. Both POPG and PI attenuated the increase in viral mRNA expression by 70% - 82% (subject numbers n=6). We determined the PI effect in an in vivo study in hamsters. Hamsters were challenged with 103 pfu of SARS-CoV-2, either with, or without PI (2mg/hamster) administered intranasally. Hamsters were harvested at Day 3, and lungs were processed for histopathology. Pharyngeal swabs were used to examine viral burden by plaque assays. PI reduced plaque numbers compared to viral infection alone groups at day1 (Virus alone: 2.4±2.7(X104pfu/ml), Virus+PI: 0.9±2.1(X106pfu/ml), p<0.05). PI reduced lung histopathology score at day 3 (Virus alone: 28.0±15.6, Virus+PI: 6.7±7.0, p<0.05). Conclusions: POPG and PI significantly reduced SARS-CoV2 replication in human differentiated airway epithelial cells. PI inhibited SARS-CoV-2 infection in vivo in hamsters. These findings suggest that inhalation of POPG, or PI might be effective as novel anti-viral compounds for treating and preventing SARSCoV- 2 infection.
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Background: Humoral innate immunity consists of a limited, but diverse, set of humoral fluid phase pattern recognition molecules (PRMs) that represent a first line of resistance against microbial invaders by promoting pathogen disposal by phagocytosis, complement activation and inflammation. These factors encompass complement, ficolin, collectin and pentraxin family of proteins. Methods: We have analyzed the activity of PRMs for their potential capacity of inhibiting SARS-CoV-2 entry and replication into epithelial cells by a microneutralization assay based on a lentiviral particles pseudotyped with the SARS-CoV-2 spike protein in HEK293T cells overexpressing the angiotensin converting enzyme 2 (ACE2). Either SARS-CoV-2 or target cells were incubated with Mannose Binding Lectin (MBL, concentration range: 1-50 μ g/ml) to further characterize its anti-viral activity for 1 h prior to infection in both human Calu-3 cells and air-liquid interface cultures of human bronchial epithelial cells (HBEC). Binding experiments were carried out with SARS-CoV-2 Spike protein and recombinant MBL to further investigate its antiviral action. Results: Among 12 PRMs tested, only MBL inhibited viral entry in the pseudotyped neutralization assay. Furthermore, MBL protein inhibited SARS-CoV-2 viral replication in Calu-3 and HBEC by ca. one log10 at the top concentration (10 μ g/ml and 50 μ g/ml, respectively). MBL antiviral activity was confirmed also against alpha, beta and gamma SARS-CoV-2 variants of concern. Binding experiments showed that MBL specifically interacts with the trimeric form of SARS-CoV-2 spike. Conclusion: MBL binds to the Spike protein in its active trimeric conformation leading to the inhibition of SARS-CoV-2 infection and replication in vitro. These results suggest that MBL possesses an antiviral activity against SARS-CoV-2 that could bear therapeutic potential.
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Introduction: Hypercalcemia is a common clinical diagnosis. Hyperparathyroidism is one of the most common etiologies. Rarely hypercalcemia is associated with intense inflammation secondary to IL-6 production. Herein we present an interesting case of hypercalcemia associated with COVID-19. Case Description: 36-year-old woman with history of Cirrhosis secondary to hepatitis C and alcohol abuse initially admitted for COVID/ARDS and cryptococcemia without CNS involvement. She was initially treated with amphotericin B and continued on fluconazole. Patient was re-admitted after 2 weeks with abdominal pain, constipation and hypercalcemia (Ca 14.2 mg/dl (normal range 8.7-10.1mg/dl). Her ionized calcium was 1.78 mmol/L (normal range 1.12-1.32 mmol/L). Serum phosphorus was 2.5 mg/dl (normal range 2.5-4.5mg/dl). Intact PTH level was 6.7 pg/ml (normal range 6-48pg/ml). Vitamin D 25-OH level was 26.8 ng/ml (sufficient range 32-100 ng/ml);Vitamin D 1,25-OH level was 7.4 pg/ml (normal 19.9-79.3pg/ml). PTH-rp was unmeasurable (< 2pmol/l). CRP was elevated at 31.7mg/L (normal range 0.2-8 mg/L). She was not on calcium, Vitamin D supplementation or thiazide diuretics. Her renal functions were normal. She was given Intravenous fluids & Intravenous pamidronate. Steroids were not used due to an ongoing fungal infection. It was proposed that the patient had Interleukin-induced hypercalcemia secondary to COVID-19 infection. Her serum calcium normalized with improvement in clinical status Discussion: Recent literature suggests COVID-19 is associated with inflammatory response with cytokines & interleukins production. IL-6 production is significantly upregulated especially in severe cases of COVID-19 known as “Cytokine storm”. IL-6 is produced by bronchial epithelial cells. High levels of IL-6 are associated with worse outcomes and much more severe disease. IL-6 in turn causes osteoclast activation, bone resorption & hypercalcemia. In our patient other potential causes of hypercalcemia were ruled out. The proposed mechanism of her hypercalcemia is an intense inflammatory response associated with COVID-19 infection. Conclusion: We present a rare sequelae of COVID-19 infection which presents a teaching point for clinicians to consider while managing such novel disease
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Background: Severe acute respiratory coronavirus 2 (SARS-CoV-2) is the infectious agent of the current COVID-19 pandemic and is responsible for more than 2 million deaths worldwide. The virus utilizes the surface receptor angiotensin-converting enzyme 2 (ACE2) to infiltrate its target cells. It has been postulated that ACE2 is a human interferon-stimulated gene (ISG) and is upregulated by interferon (IFN) and virus stimulation. However, previous studies showed that not ACE2, moreover a novel short isoform of the enzyme is mainly expressed after IFN stimulation. Method: In this study, we aimed to investigate the impact of IFN stimulation on ACE2 expression in human bronchial epithelial cells. We measured the expression levels of two ACE2 isoforms, namely the full-length isoform and the IFN-induced truncated isoform proposed by Onabajo et al. (truncACE2) at the transcription and protein level following stimulation of Calu-3 and primary human bronchial epithelial cells (NHBE) with type-I,-II and-III IFNs. Specific primers along the ACE2 coding sequence were used for quantitative and semi-quantitative analysis of the transcript isoforms. Induced ACE2 protein isoforms were additionally analyzed using immunoblotting. Results: In both, the Calu3 cell line and the NHBE, truncACE2 was dose-dependently upregulated at the transcription level after 6h of IFNγ stimulation, whereas the full-length transcript levels did not change. IFNs of type-I and type-III stimulation induced a dosedependent upregulation of both ACE2 versions at the mRNA level, although the truncACE2 showed a higher expression level. In the immunoblotting analysis, neither the full-length nor the truncated ACE2 version showed a difference after IFNγ stimulation of NHBE. Conclusion: This study is in line with previous findings that only a truncated ACE2 isoform acts as an ISG. However, our data additionally show that not only type-II, but also type-I and type-III interferons induce this truncated version of ACE2. This is especially important, as type-I and type-III IFNs are secreted during the initial epithelial host response to the virus. It remains to be uncovered whether SARS-CoV-2 can utilize also truncACE2 to enter cells thereby using the initial host response to increase truncACE2 and facilitate viral spread.