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Background & Aim: The pro-angiogenic, immunoregulatory and anti- inflammatory properties of MSCs are being exploited for the development of cellular therapies, including the treatment of graft versus host disease (GvHD), inflammatory bowel disease and COVID-19. SNBTS have developed a GMP process to bank umbilical cord MSCs (UC-MSCs) whereby we can reliably bank 100 vials of 10 million P2 UC-MSCs per cord. Each of these vials can be extensively expanded and stored for specific applications. The ultimate aim of the bank is for off-the-shelf clinical use, e.g., in GvHD or as an adjuvant therapy in Islet transplantations. Methods, Results & Conclusion(s): During process development, different basal media and supplements were screened for proliferation and MSC marker expression. Cells grown in promising media combinations were then tested for tri-lineage differentiation (identity), their chemokine/cytokine expression and T-cell inhibition (function) assessed. Medium selected for further GMP development and scale up was ultimately determined by all round performance and regulatory compliance. GMP-like UC-MSCs were shown to have immune-modulatory activity in T-cell proliferation assays at 4:1 or 16:1 ratios. Co-culture of UC-MSCs and freshly isolated leukocytes, +/- the immune activating agent LPS, show a dose dependent survival effect on leukocytes. In particular, neutrophils, which are normally very short lived in vitro demonstrated increased viability when co-cultured with UCMSCs. The survival effect was partially reproduced when UC-MSC were replaced with conditioned medium or cell lysate indicating the involvement of soluble factors. This improved neutrophil survival also correlates with results from leukocyte migration studies that demonstrate neutrophils to be the main cell type attracted to MSCs in in vitro and in vivo. Genetic modification of UC-MSC may improve their therapeutic potential. We have tested gene editing by CRISPR/Cas9 technology in primary UC-MSCS. The CXCL8 gene, highly expressed in UC-MSC, was targeted in isolates from several different donors with editing efficiencies of 78-96% observed. This translated to significant knockdown of CXCL8 protein levels in resting cells, however after stimulation levels of CXCL8 were found to be very similar in edited and non-edited UC-MSCs. This observation requires further study, but overall the results show the potential to generate future banks of primary UC-MSCS with genetically enhanced pro-angiogenic, immunoregulatory and/or anti-inflammatory activities.Copyright © 2023 International Society for Cell & Gene Therapy
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Background: Angiotensin-converting enzyme 2 (ACE2), the pulmonary epithelial receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), plays a significant role in attenuating muscle fibrosis in dystrophic muscle models. Evidence suggests ACE2 is downregulated in prolonged hypoxia by hypoxia-inducible factor 1-alpha (HIF1-alpha). We hypothesize that myoblasts affected by chronic ischemia would have attenuated ACE2 expression, potentially modifying the detection of and response to SARS-CoV-2 infection in muscle tissue. This holds an important impact for peripheral arterial disease (PAD) patients who are also at risk for severe coronavirus disease 2019 (COVID) infection based on age. Method(s): Cells were harvested from ischemic and perfused muscle during lower extremity amputations and bypasses in PAD patients. Myoblasts (Pax7-/MyoD+) were isolated using preplating technique and cell sorting. Commercially available healthy donors myoblasts (PAD-) were purchased (Cook MyoSite). All experiments were performed in normoxic (20% O2) and hypoxic (1% O2) conditions. ACE2 expression was quantified via immunofluorescence staining after five days differentiation. HIF1-alpha ELISAs (Elabscience) were performed on cell lysates after 24 hours of proliferation. Cell lysis in response to exposure to COVID spike protein (RayBiotech) was assessed using lactate dehydrogenase assays (Invitrogen). Analysis of variance with post hoc analysis confirmed statistical significance (alpha = 0.05). Result(s): Hypoxia exposure induced significant increase in HIF1-alpha expression in perfused myoblasts (P <.05). Hypoxia also increased ACE2 expression in ischemic (n = 6) compared to perfused (PAD-, n = 2;perfused PAD, n = 5) (P <.05) myoblasts (Figure, A). Lactate dehydrogenase concentration suggestive of cell lysis and cytotoxicity was higher in perfused than ischemic myoblasts. Myoblasts from perfused muscle also had higher cell lysis from COVID spike protein exposure while ischemic cells exposed to COVID spike proteins seemed to survive (Figure, B). Conclusion(s): Chronically ischemic myoblasts from PAD muscle increased ACE2 expression in response to additional hypoxia. This may suggest greater susceptibility of ischemic muscle to SARS-CoV-2 effects in the setting of additional hypoxic insults like pneumonia. While cytotoxicity was not a feature of spike protein exposure in ischemic PAD cells, this might suggest cell survival in the setting of viral infection, which is unfavorable. Further research is needed to understand whether cell survival mechanisms exist in PAD myoblasts exposed to COVID infection. [Formula presented] Copyright © 2022
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Background: COVID-19 is accompanied by excessive systemic thrombotic events, but the mechanism is unknown. All major COVID-19 vaccines were associated with thrombosis. Thymidine phosphorylase (TYMP) plays an important role in platelet activation, thrombosis, and inflammation. TYMP expression is significantly increased in COVID-19 patients. Aim(s): To test the hypothesis that TYMP mediates SARS-CoV-2 spike protein (SP)-enhanced thrombosis. Method(s): Transfection of plasmid encoding SP or the receptor-binding domain (RBD) with human ACE2 was conducted in COS-7 cells. BEAS-2B cells were treated with SP or RBD containing COS-7 cell lysates, and TYMP expression and activation of NF-kappaB were examined. K18-hACE2 transgenic (ACE2-TG) mice were intraperitoneally treated with SP or RBD containing COS-7 cells lysates, and thrombosis was assessed three days later using the FeCl3 injury-induced carotid artery thrombosis model. Result(s): SP and RBD led to ACE2 shedding, significantly increased TYMP expression, and NF-kappaB activation in BEAS-2B cells. In comparison to wildtype mice, ACE2-TG mice are anti-thrombotic and had significantly prolonged thrombosis time. Treating ACE2-TG mice with COS-7 cells transfected with empty plasmid did not affect the thrombosis. However, treating the ACE2-TG mice with SP-or RBD-containing COS-7 cell lysates dramatically enhanced thrombosis and significantly shortened time to occlusive thrombi formation. SP is more powerful than RBD in enhancing thrombosis. SP-enhanced thrombosis was dramatically inhibited by simultaneously feeding the mice with 1 mg/kg of tipiracil. TYMP is expressed in human type II alveolar epithelial cells and bronchial epithelium. By using the MGH Emergency Department COVID-19 Cohort with Olink Proteomics TYMP data and Receiver Operating Characteristic analysis, we found TYMP is a sensitive and specific marker in diagnosing COVID-19 (AUC 0.8721, p < 0.0001). Conclusion(s): SARS-CoV-2 SP and RBD are pro-inflammatory and pro-thrombotic. SP/RBD-induced thrombosis is inhibited by tipiracil, a TYMP inhibitor. TYMP is a sensitive marker for COVID-19 diagnosis. Targeting TYMP could be a novel effective treatment for COVID-19.
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Background: There is emerging evidence of microvascular thrombosis and thrombotic microangiopathy (TMA) induced by COVID-19, presumably from endothelial injury or endotheliopathy . Thrombomodulin (TM) is an endothelial glycoprotein that plays a crucial role as a natural anticoagulant, binding thrombin to activate protein C (PC). TM is shed from endothelial surface during injury. We hypothesize SARS-CoV-2 spike proteins cause direct microvascular endothelial injury, leading to TM shedding, decreased activation of PC, and consequently, microvascular thrombosis in COVID-19. Aim(s): To assess: 1) endothelial injury (by soluble TM [sTM] levels) in a cohort of critically-ill COVID-19 pediatric patients;2) endothelial injury (TM shedding) in vitro by SARS-CoV-2 spike proteins and the subsequent functional consequence in activated PC (APC) levels. Method(s): STM in plasma samples from SARS-CoV-2 positive patients admitted to Texas Children's Hospital Pediatric Intensive Care Unit (n = 34) and healthy controls (n = 38) were measured by ELISA. IRB approval and waiver of informed consent were obtained. In vitro, confluent glomerular microvascular endothelial cells (GMVECs) were incubated for 24 hours in the presence or absence (control) of purified SARS-CoV-2 spike proteins, S1 and S2. In some experiments, cell lysates were collected, and TM was measured by ELISA;in others, GMVECs were further supplemented with PC and thrombin for 1 hour, followed by supernatant collection for APC measurement by ELISA. Result(s): STM levels were significantly higher in the COVID-19 pediatric patients (p < 0.01) (Fig. 1). In vitro, surface bound TM (Fig 2a) and soluble APC (Fig 2b) were significantly lower in GMVECs after addition of spike proteins (p < 0.05). Conclusion(s): We provide evidence of endothelial injury in COVID-19 patients and demonstrate a potential pathway of SARS-CoV-2 induced thrombosis. Decreased surface-bound TM results in lower amount of thrombin-TM complex, hence lesser activation of PC, likely leading to a pro-thrombotic state. These findings in GMVECs could explain the vulnerability of kidneys to COVID-19-induced TMA.
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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: Individuals with COPD who develop COVID-19 are at increased risk of hospitalization, ICU admission and death. COPD is associated with increased airway epithelial expression of ACE2, the receptor mediating SARS-CoV-2 entry into cells. Hypercapnia commonly develops in advanced COPD and is associated with frequent and potentially fatal pulmonary infections. We previously reported that hypercapnia increases viral replication, lung injury and mortality in mice infected with influenza A virus. Also, global gene expression profiling of primary human bronchial epithelial (HBE) cells showed that elevated CO2 upregulates expression of cholesterol biosynthesis genes, including HMGCS1, and downregulates ATP-binding cassette (ABC) transporters that promote cholesterol efflux. Given that cellular cholesterol is important for entry of viruses into cells, in the current study we assessed the impact of hypercapnia on regulation of cellular cholesterol levels, and resultant effects on expression of ACE2 and entry of Pseudo-SARS-CoV-2 in cultured HBE, BEAS-2B and VERO cells, and airway epithelium of mice. Methods: Differentiated HBE, BEAS-2B or VERO cells were pre-incubated in normocapnia (5% CO2, PCO2 36 mmHg) or hypercapnia (15% CO2, PCO2 108 mmHg), both with normoxia, for 4 days. Expression of ACE2 and sterol regulatory element binding protein 2 (SREPB2), the master regulator of cholesterol synthesis, was assessed by immunoblot or immunofluorescence. Cholesterol was measured in cell lysates by Amplex red assay. Cells cultured in normocapnia or hypercapnia were also infected with Pseudo SARS-CoV-2, a Neon Green reporter baculovirus. For in vivo studies, C57BL/6 mice were exposed to normoxic hypercapnia (10% CO2/21% O2) for 7 days, or air as control, and airway epithelial expression of ACE2, SREBP2, ABCA1, ABCG1 and HMGCS1 was assessed by immunofluorescence. SREBP2 was blocked using the small molecules betulin or AM580, and cellular cholesterol was disrupted using MβCD. Results: Hypercapnia increased expression and activation of SREBP2 and decreased expression of ABC transporters, thereby augmenting epithelial cholesterol levels. Elevated CO2 also augmented ACE2 expression and Pseudo-SARSCoV- 2 entry into epithelial cells in vitro and in vivo. These effects were all reversed by blocking SREBP2 or disrupting cellular cholesterol. Conclusion: Hypercapnia augments cellular cholesterol levels by altering expression of cholesterol biosynthetic enzymes and efflux transporters, leading to increased epithelial expression of ACE2 and entry of Pseudo-SARS-CoV-2 into cells. These findings suggest that ventilatory support to limit hypercapnia or pharmacologic interventions to decrease cellular cholesterol might reduce viral burden and improve clinical outcomes of SARSCoV- 2 infection in advanced COPD and other severe lung diseases.
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BACKGROUND AND AIM: E. coli are widely used for recombinant protein development, due to its low cost, ease of manipulation, and availability of well established molecular tools and techniques. Due to a lack of sophisticated machinery to undertake posttranslational modifications, the E. coli bacterial culture is limited in its ability to express more complex proteins, resulting in low solubility of the protein of interest that is generated as inclusion bodies. Although we were able to produce the recombinant SARS-CoV-2-S1 protein at high expression levels in our earlier investigation, we were also able to obtain nearly the whole protein as inclusion body. To overcome this problem, different solubility strategies have been tried. In this study, we developed an E.coli expression strategy based on the expression of the S1 protein as a fusion of SUMO fusion protein. METHODS: The DNA sequence of S1 protein was cloned into the pET SUMO expression vector, resulting in a construct expressing a N-terminal tag SUMO fusion protein. To achieve the high-level expression of S1, small scale expression conditions were optimized in E. coli BL21 (DE3) containing pET SUMO-S1 with different induction temperatures, times and IPTG concentrations. Additionally, different medium was also tested for the expression of S1 protein. For each parameter, solubility and expression of cell lysates from uninduced and induced cultures, plus the soluble and insoluble fractions from induced cultures were analyzed by SDS-PAGE and Western Blot. RESULTS: SDS-PAGE and Western Blot analysis showed the presence of a ∼83 kDa recombinant fusion protein. The maximum level of expression of the recombinant protein was observed at 30 , 4 h after induction with 0,55 mM IPTG. CONCLUSIONS: This study showed that the use of SUMO fusion tag partially increases the production of S1 protein in the form of soluble fractions and optimization studies continue.
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Background: Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) disease (COVID19) mainly affects the respiratory system, but cardiac complications occur very often. SARS-CoV-2 entry in host cells is mediated by the interaction between the viral Spike (S) glycoprotein and the host angiotensin-converting enzyme 2 (ACE2). The use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II type 1 receptor blockers (ARBs) might influence the expression of ACE2 and viral infection, but not much is known about these interactions. Aim: To evaluate the effects of ACEIs and ARBs during active viraemia. Methods: We tested the ACEI Lisinopril (at 100nM and 500nM) and the ARB Valsartan (at 10uM and 50uM) for one week on two cell types: cardiomyocytes derived from hiPSC (hiPSC-CMs) as heart model and a lung epithelial cancer cell line (16HBE) as pulmonary model. The SARS-CoV-2 wild strain was inoculated in the two treated cell types for one hour. Cell viability was measured 72 hours after infection. Supernatants were collected and titrated to verify the presence of infectious virus using a micro-neutralization assay on VERO-E6 cells. Levels of ACE2 mRNA and protein content on cell lysates were quantified after each treatment by RT-qPCR and western blot, respectively. Results: ACEI and ARB at both concentrations affected the viability of neither hiPSC-CMs nor 16HBE cells in the absence of virus. Vice versa, viral infection significantly decreased viability of both hiPSC-CMs (-46%;p<0,01) and 16HBE (-19%;p<0,05). Viral titration revealed that SARSCoV-2 replicated in both cell lines and was actively released in supernatants. Importantly, pretreatment with Valsartan 50uM increased the viability of both hiPSC-CMs and 16HBE after infection, while Lisinopril and the lower dose of Valsartan had neutral effect. Of note, Valsartan 50uM treatment decrease ACE2 mRNA level in both hiPSC-CMs (-47%, p<0,01) and 16HBE (-37%, p<0,01). Also ACE2 protein levels were reduced in cell lysates of hiPSC-CMs and 16HBE treated with Valsartan 50uM. Conclusion: These data suggest that ACEIs and ARBs do not worsen the SARS-CoV-2 infection. On the contrary, Valsartan seems to be protective against SARS-CoV-2 infection, possibly by reducing ACE2 expression.
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Introduction: Banana Lectin (BanLec) is a glycoprotein-binding lectin derived from banana fruit that has antiviral activity. BanLec binds high mannose glycans expressed on the viral envelopes of HIV, Ebola, influenza, and coronaviruses. BanLec mitogenicity can be divorced from antiviral activity via a single amino acid change (H84T). The SARS-CoV-2 spike (S) protein is decorated with high mannose N-glycosites that are in close proximity to the viral receptor binding domain (RBD). Our goal was to use the H84T-BanLec as the extracellular targeting domain of a chimeric antigen receptor (CAR). We hypothesized that engineering NK cells to express an H84T-BanLec CAR would specifically direct antiviral cytotoxicity against SARS-CoV-2. Methods: H84T-BanLec was synthesized and added to a 4-1BB.ζ CAR by subcloning into an existing retroviral vector. To modify primary human NK cells, CD3-depleted peripheral blood mononuclear cells were first activated with lethally irradiated feeder cells (K562.mbIL15.4-1BBL), then transduced with transiently produced replication incompetent γ-retrovirus carrying the H84T-BanLec.4-1BB.ζ CAR construct. Vector Copy Number (VCN) per cell was measured and CAR protein expression detected with Western blotting. 293T cells were engineered to express human ACE2 (hACE2.293T), the binding receptor for SARS-CoV-2. CAR expression on NK cells and SARS-CoV-2 S-protein binding to hACE2.293T were measured using FACS. S-protein pseudotyped lentivirus carrying a firefly Luciferase (ffLuc) reporter was produced. Viral infectivity was measured using bioluminescence (BL) detection in virally transduced cells. H84T-BanLec CAR NK cells were added to our S-protein pseudotyped lentiviral infectivity assay and degree of inhibited transduction was measured. NK cell activation was assessed with detection of IFNγ and TNFα secretion using ELISA. Results: A median of 4.5 integrated H84T-BanLec CAR copies per cell was measured (range 3.5-7.45, n=4). The CAR was detected by Western blot in NK cell lysates using antibodies to TCRζ and H84T-BanLec. Surface expression of the CAR on primary NK cells was recorded on day 4 after transduction (median [range], 67.5% CAR-positive [64.7-75%], n=6;Fig. 1). CAR expression was maintained on NK cells in culture for 14 days (58.9% CAR-positive [43.6-66.7%], n=6;Fig. 1). ACE2 expression and binding of recombinant S-proteins to hACE2 on hACE2.293T but not parental 293Ts was verified. S-protein pseudotyped lentiviral transduction of hACE2.293T was confirmed with increase in BL from baseline across diminishing viral titer (n=3;Fig. 2). Control 293T cells without hACE2 expression were not transduced, confirming specificity of viral binding and entry dependent on hACE2 (n=3;Fig. 2). S-protein pseudoviral infectivity of hACE2.293T cells was inhibited by both H84T-BanLec CAR-NK and unmodified NK cells, with enhanced inhibition observed in the CAR-NK condition (mean % pseudovirus infectivity +/- SEM of hACE2.293T in co-cultures with unmodified NK vs. H84T-BanLec CAR-NK;65 +/-11% vs 35%+/- 6% for 1:1 effector-to-target ratio, p=0.05;78 +/-3% vs 68%+/- 3% for 1:2.5 effector-to-target ratio, p=0.03;n=6;Fig.3). Both unmodified and H84T-BanLec CAR-NK cells were stimulated to secrete inflammatory mediators when co-cultured with pseudoviral particles and virally infected cells. CAR-NK cells showed overall higher cytokine secretion both at baseline and with viral stimulation. Conclusions: A glycoprotein binding H84T-BanLec CAR was stably expressed on the surface of NK cells. CAR-NK cells are activated by SARS-CoV-2 S-pseudovirus and virally infected cells. Viral entry into hACE2 expressing cells was inhibited by H84T-BanLec CAR-NK cells. Translation of H84T-BanLec CAR-NK cells to the clinic may have promise as an effective cellular therapy for SARS-CoV-2 infection. [Formula presented] Disclosures: Markovitz: University of Michigan: Patents & Royalties: H84T BanLec and of the H84T-driven CAR construct. Bonifant: Merck, Sharpe, Dohme: Research Funding;BMS: Research Funding;Kiadis Pharma: Rese rch Funding.