Biological Investigation of Amaryllidaceae Alkaloid Extracts from the Bulbs of Pancratium trianthum Collected in the Senegalese Flora

Amaryllidaceae plants are rich in alkaloids with biological properties. Pancratium trianthum is an Amaryllidaceae species widely used in African folk medicine to treat several diseases such as central nervous system disorders, tumors, and microbial infections, and it is used to heal wounds. The current investigation explored the biological properties of alkaloid extracts from bulbs of P. trianthum collected in the Senegalese flora. Alkaloid extracts were analyzed and identified by chromatography and mass spectrometry. Alkaloid extracts from P. trianthum displayed pleiotropic biological properties. Cytotoxic activity of the extracts was determined on hepatocarcinoma Huh7 cells and on acute monocytic leukemia THP-1 cells, while agar diffusion and microdilution assays were used to evaluate antibacterial activity. Antiviral activity was measured by infection of extract-treated cells with dengue virus (DENVGFP) and human immunodeficiency virus-1 (HIV-1GFP) reporter vectors. Cytotoxicity and viral inhibition were the most striking of P. trianthum’s extract activities. Importantly, non-cytotoxic concentrations were highly effective in completely preventing DENVGFP replication and in reducing pseudotyped HIV-1GFP infection levels. Our results show that P. trianthum is a rich source of molecules for the potential discovery of new treatments against various diseases. Herein, we provide scientific evidence to rationalize the traditional uses of P. trianthum for wound treatment as an anti-dermatosis and antiseptic agent.

Antirheumatic Drugs against COVID-19 from the Perspective of Rheumatologists

Coronavirus disease 2019 (COVID-19) remains a global threat to humanity. Its pathogenesis and different phases of disease progression are being elucidated under the pandemic. Active viral replication activates various immune cells and produces large amounts of inflammatory cytokines, which leads to the cytokine storm, a major cause of patient death. Therefore, viral inhibition is expected to be the most effective early in the course of the disease, while immunosuppressive treatment may be useful in the later stages to prevent disease progression. Based on the pathophysiology of rheumatic diseases, various immunomodulatory and immunosuppressive drugs are used for the diseases. Due to their mechanism of action, the antirheumatic drugs, including hydroxychloroquine, chloroquine, colchicine, calcineurin inhibitors (e.g., cyclosporine A and tacrolimus), glucocorticoids, cytokines inhibitors, such as anti-tumor necrosis factor-α (e.g., infliximab), anti-interleukin (IL)-6 (e.g., tocilizumab, sarilumab, and siltuximab), anti-IL-1 (e.g., anakinra and canakinumab) and Janus kinase inhibitors (e.g., baricitinib and tofacitinib), cytotoxic T lymphocyte-associated antigen 4 blockade agents (e.g., abatacept), and phosphodiesterase 4 inhibitors (e.g., apremilast), have been tried as a treatment for COVID-19. In this review, we discuss the mechanisms of action and clinical impact of these agents in the management of COVID-19.

Virucidal effect of povidone-iodine against SARS-CoV-2 in vitro

Objective To evaluate the antiviral activity of the oral disinfectant povidone-iodine (PVP-I) against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV2) in vitro. Methods The cytotoxic effects of PVP-I were determined in Vero and Calu-3 cell lines using that by Cell Counting Kit-8 assay. Viral load in the cell culture medium above infected cells was quantitated using real-time polymerase chain reaction. The cytopathic effect (CPE) and viral infective rate were observed by immunofluorescence microscopy. Results PVP-I at a concentration >0.5 mg/ml in contact with SARS-CoV-2 for 30 s, 1 min, 2 min and 5 min showed up to 99% viral inhibition. For in vitro testing, upon exposure for 1 min, PVP-I showed a virucidal effect. PVP-I had no cytotoxic effects at the range of concentrations tested (0.125–1 mg/ml; CC50 > 2.75 mM) in Vero and Calu-3 cells. Conclusion These results demonstrate that the ideal contact time was 1 min and the optimal concentration was 1 mg/ml, which provides an experimental basis for the use of oral disinfectants in dental hospitals.

Deep learning methods for designing proteins scaffolding functional sites

Current approaches to de novo design of proteins harboring a desired binding or catalytic motif require pre-specification of an overall fold or secondary structure composition, and hence considerable trial and error can be required to identify protein structures capable of scaffolding an arbitrary functional site. Here we describe two complementary approaches to the general functional site design problem that employ the RosettaFold and AlphaFold neural networks which map input sequences to predicted structures. In the first "constrained hallucination" approach, we carry out gradient descent in sequence space to optimize a loss function which simultaneously rewards recapitulation of the desired functional site and the ideality of the surrounding scaffold, supplemented with problem-specific interaction terms, to design candidate immunogens presenting epitopes recognized by neutralizing antibodies, receptor traps for escape-resistant viral inhibition, metalloproteins and enzymes, and target binding proteins with designed interfaces expanding around known binding motifs. In the second "missing information recovery" approach, we start from the desired functional site and jointly fill in the missing sequence and structure information needed to complete the protein in a single forward pass through an updated RoseTTAFold trained to recover sequence from structure in addition to structure from sequence. We show that the two approaches have considerable synergy, and AlphaFold2 structure prediction calculations suggest that the approaches can accurately generate proteins containing a very wide array of functional sites.

Antibody Response after Vaccination for Sars-Cov-2 in Patients with AL Amyloidosis and the Impact of Therapy

Patients with lymphoproliferative disorders are at high risk for severe COVID-19. For patients with AL amyloidosis, in which there is also critical organ involvement, this risk may be even higher. Vaccination against SARS-CoV-2 is the best strategy to avoid severe COVID-19, but response to vaccines may be compromised in patients with B-cell lymphoproliferative or plasma cell malignancies, as in AL amyloidosis. Although modest in size, the plasma cell clone in AL may cause immunosuppression while anticlonal therapies further compromise immune responses. To evaluate immunization efficacy, we measured the titers of neutralizing antibodies (NAbs) against SARS-CoV-2 after vaccination with BNT162b2 in patients with AL amyloidosis. As a control group we used volunteers, matched (ratio 1:2) for age and gender, who had no autoimmune or active malignant or infectious disease. Serum was separated within 4 hours from blood collection and stored at -80°C until the day of measurement on (A) day 1 (D1; before the first dose of BNT162b2) (B) day 22 (D22; before the 2nd dose) and (C) day 50 (D50; ie 30 days after the 2nd dose). NAbs against SARS-CoV-2 were measured using FDA approved methodology (cPass™ SARS-CoV-2 NAbs Detection Kit; GenScript, Piscataway, NJ, USA). According to the manufacturer of the assay, a titer ≥ 50% is considered a clinically relevant threshold for viral inhibition. The study included 144 patients with AL amyloidosis, of which 120 had NAbs titers assessed on all time points and were included in the final analysis (53% males; median age: 66, IQR: 57-72 years) and 240 matched controls (53% males; median age: 66, IQR: 57-72 years). 66 (55%) AL patients were on active therapy, 17.5% were on daratumumab (DARA)-based therapy, 52 (43%) had discontinued therapy >3 months from the date of the first shot, 19% had prior exposure to DARA and 94 (78%) were in hematologic remission (CR or VGPR). Prior to the 1st dose (D1), NAb titers were similar between patients and controls (median 14.9% (IQR 7.8-23.1%) vs 14% (IQR 6.8-22.9%), p=0.439); 6 AL patients had baseline NAbs >50%, of which 5 reported a history of COVID-19 infection. On D22, there was a significant increase of NAbs titers both in controls and AL patients (both p<0.001); however, median NAb titer was 23.6% (IQR 12.4-37.7%) in AL patients vs 47.5% (IQR 32.1-62.7%) in controls (p<0.001) and 20.5% of AL patients vs 46.7% of controls (p<0.001) developed NAb titers ≥50%. On D50, there was further increase in NAbs titers both in controls and AL patients (both p<0.001) and median NAb titer for AL patients was 83.1% (IQR 41.5-94.9%) vs 95.6% (IQR 91.7-97.2%) in controls (p<0.001); 71% of AL patients vs 98% of matched controls (p<0.001) developed NAb titers ≥50%. Among AL patients, factors associated with NAb titers on D50 included age (p<0.001), lymphocyte counts (p<0.001), serum albumin (p<0.001) and amount of proteinuria at the time of vaccination (p=0.047), renal involvement (p=0.047), use of steroids (p<0.001), active treatment (p<0.001), treatment-free interval (p=0.001), remission status (CR/VGPR) (p=0.018). There was no significant association with gender (p=0.092), BMI (p=0.198), IgG (0.099), IgA (p=0.789) or IgM levels (p=0.687), liver (p=0.521) or heart involvement (p=0.141). Patients on therapy had lower NAb titers at D50 (median 50.1% (IQR 25.3-84.1%) vs 91.6% (IQR 74.5-96.5%) for those not on treatment, p<0.001), so that 51% had a D50 NAb titer ≥50% vs 87% of those not on therapy. Current DARA therapy (median 52.1% vs 46.4% without DARA, p=0.486) or prior exposure to DARA (92.1% vs 91.2%, p=0.966) were not associated with D50 NAb titers. Generalized linear models were used for evaluation of multiple factors associated with D50 NAb titers: at least 3 months since the last dose of anticlonal therapy (p<0.001), lymphocyte counts (p=0.001) and serum albumin levels at the time of vaccination (p=0.020) were independent predictors of NAb titers on D50. When seroconversion was defined as a NAb titer ≥50% at D50, then >3 months of treatment-free interval (HR:7.75, p<0.001,) was the strongest factor associated with seconversion. In conclusion, patients with AL amyloidosis have an attenuated response to vaccination with BNT162b2 especially among those on active therapy or with less than 3 months since the last dose of treatment. For such patients, an anamnestic dosing strategy could be considered, especially after completion of anticlonal therapy. Figure 1 Figure 1. Disclosures Kastritis: Genesis Pharma: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Terpos: Novartis: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Genesis: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; BMS: Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; GSK: Honoraria, Research Funding. Gavriatopoulou: Sanofi: Honoraria; GSK: Honoraria; Karyopharm: Honoraria; Takeda: Honoraria; Genesis: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Dimopoulos: Amgen: Honoraria; BMS: Honoraria; Janssen: Honoraria; Takeda: Honoraria; BeiGene: Honoraria.

Poor Neutralizing Antibody Responses in Patients with CLL, NHL and HL after Vaccination Against Sars-Cov-2; A Prospective Study in 132 Patients

Introduction: Recent data suggest a suboptimal antibody response to COVID-19 vaccination in patients with hematological malignancies, especially under therapy with monoclonal antibodies targeting B-cells. Herein, we evaluated the development of neutralizing antibodies (NAbs) against SARS-CoV-2 in patients with chronic lymphocytic leukemia (CLL), Non-Hodgkin Lymphoma (NHL) and Hodgkin's Lymphoma (HL) after vaccination with the mRNA BNT162b2 vaccine, up to 50 days post their first vaccine dose. Methods: This is a large prospective study (NCT04743388) evaluating the kinetics of anti-SARS-CoV-2 antibodies after COVID-19 vaccination in healthy subjects and patients with hematological malignancies. We report here the results in CLL, NHL and HL patients in comparison to age- and gender-matched controls who were vaccinated at the same time period (January to May 2021). After vein puncture, the serum of both patients and controls was collected on day 1 (D1; before the first BNT162b2 dose), on day 22 (D22; before the second dose of the BNT162b2) and on day 50 (D50; 3 weeks post second dose of the BNT162b2). Serum was separated within 4 hours from blood collection and stored at -80°C until the day of measurement. NAbs against SARS-CoV-2 were measured using FDA approved methodology (ELISA, cPass™ SARS-CoV-2 NAbs Detection Kit; GenScript, Piscataway, NJ, USA) on the abovementioned timepoints. A NAb titer of at least 30% is considered as positive, according to manufacturer, whereas a NAb titer of at least 50% has been associated with clinically relevant viral inhibition [Walsh et al. N Engl J Med 2020, 383, 2439-50]. Samples of the same individual were measured in the same ELISA plate. Results: We evaluated 132 patients with CLL/Lymphomas after vaccination with the BNT162b2. Patient population included 53 with CLL, 57 with NHL and 22 with HL, while 214 healthy controls, of similar age and gender, were also studied. At the time of vaccination, 30% (n=40) of patients had asymptomatic disease and out of 92 symptomatic patients, 49% (n=45) were on active treatment. Vaccination with two doses of the BNT162b2 led to lower production of NAbs against SARS-CoV-2 in patients compared with controls, both on day 22 and on day 50 (P<0.001 for all comparisons) for all subgroups. After the first dose of the vaccine, on D22, the patient group had lower NAb titers compared with controls: the median NAb inhibition titer was 18% (IQR: 8.5-29%) for patients versus 41.6% (IQR: 25.3-59%) for controls; p<0.001. On D50, the median NAb inhibition titer was 32.5% (IQR: 13.5-93%) for patients versus 94.7% (IQR: 89-97%) for controls; p<0.001. More specifically, only 50.8% (67/132) of the patients versus 98.1% (210/214) of the controls developed NAb titers ≥30% and 43.9% (58/132) of patients versus 95.3% (204/214) titers ≥50% (high protective titers) at day 50 (p<0.0001 for all comparisons; Figure-left part). Importantly, active treatment (which included anti-CD antibodies, Bruton's tyrosine kinase inhibitors, a combination of the above, chemotherapy-only regimens or Bcl-2 inhibitors) was an independent prognostic factor for suboptimal antibody response at day 50 (<50%) in the patient subgroup (p<0.001). Rituximab administration in the last 12 months correlated with decreased antibody response at day 50 (p<0.01). Patients with HL were more likely to achieve humoral responses (>50% at day 50) compared to other disease types (p<0.05; Figure-right part). Disease-related immune dysregulation and therapy-related immunosuppression were therefore involved in the low humoral responses seen in patients. Regarding adverse events, 9% and 9.8% patients reported mild reactions after the first and second dose of the BNT162b2 vaccine, respectively. Conclusion: Patients with CLL/NHL/HL have a low humoral response following SARS-CoV-2 vaccination, particularly patients who are on active treatment with rituximab or BTK inhibitors. These patient subgroups therefore should continue utilizing protective measures against SARS-CoV-2 (masks, social distancing, etc) as they are at high risk for COVID-19. Further studies on the kinetics of immune subpopulations following COVID-19 vaccination will elucidate the underlying immune landscape and determine the potential need for additional booster vaccine doses or protective administration of antibodies against SARS-CoV-2 in CLL/NHL/HL patients with poor response after full vaccination. Figure 1 Figure 1. Disclosures Terpos: Sanofi: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding; GSK: Honoraria, Research Funding; Genesis: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Gavriatopoulou: Janssen: Honoraria; GSK: Honoraria; Genesis: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; Karyopharm: Honoraria. Baltadakis: Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Alexion: Honoraria; Astellas: Honoraria; Pfizer: Honoraria, Other: Travel Grants; Gilead: Honoraria; Novartis: Honoraria; Abbvie: Honoraria; Genesis Pharma: Other: Travel Grants; Gilead: Other: Travel Grants; WinMedica: Other: Travel Grants; Baxalta Hellas: Other: Travel Grants. Dimopoulos: BMS: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Beigene: Honoraria.

Investigation of monotherapy and combined anticoronaviral therapies against feline coronavirus serotype II in vitro

Objectives Feline infectious peritonitis (FIP), caused by genetic mutants of feline enteric coronavirus known as FIPV, is a highly fatal disease of cats with no currently available vaccine or US Food and Drug Administration-approved cure. Dissemination of FIPV in affected cats results in a range of clinical signs, including cavitary effusions, anorexia, fever and lesions of pyogranulomatous vasculitis and perivasculitis, with or without central nervous system or ocular involvement. The objectives of this study were to screen an array of antiviral compounds for anti-FIPV (serotype II) activity, determine cytotoxicity safety profiles of identified compounds with anti-FIPV activity and strategically combine identified monotherapies to assess compound synergy against FIPV in vitro. Based upon clinically successful combination treatment strategies for human patients with HIV and hepatitis C virus infections, we hypothesized that a combined anticoronaviral therapy approach featuring concurrent multiple mechanisms of drug action would result in an additive or synergistic antiviral effect. Methods This study screened 90 putative antiviral compounds for efficacy and cytotoxicity using a multimodal in vitro strategy, including plaque bioassays, real-time RT-PCR viral inhibition and cytotoxicity assays. Results Through this process, we identified 26 compounds with effective antiviral activity against FIPV, representing a variety of drug classes and mechanisms of antiviral action. The most effective compounds include GC376, GS-441524, EIDD2081 and EIDD2931. We documented antiviral efficacy for combinations of antiviral agents, with a few examined drug combinations demonstrating evidence of limited synergistic antiviral activity. Conclusions and relevance Although evidence of compound synergy was identified for several combinations of antiviral agents, monotherapies were ultimately determined to be the most effective in the inhibition of viral transcription.

Sandacrabins – Structurally unique antiviral RNA polymerase inhibitors from a rare myxobacterium

We report structure elucidation and total synthesis of five unprecedented terpenoid-alkaloids, the sandacrabins, alongside with the first description of their producing organism Sandaracinus defensii MSr10575, which expands the Sandaracineae family by only its second member. The genome sequence of S. defensii as presented in this study was utilized to identify enzymes responsible for sandacrabin formation, whereby dimethylbenzimidazol, deriving from cobalamin biosynthesis, was identified as key intermediate. Biological activity profiling revealed that all sandacrabins except congener A exhibit potent antiviral activity against the human pathogenic coronavirus HCoV229E in the three digit nanomolar range. Investigation of the underlying mode of action discloses that the sandacrabins inhibit the SARS-CoV-2 RNA-dependent RNA polymerase complex, highlighting them as structurally distinct non-nucleoside RNA synthesis inhibitors. The observed segregation between cell toxicity at higher concentrations and viral inhibition represents a good starting point for their medicinal chemistry optimization towards selective inhibitors.