Critical role of defensins in respiratory viral infection induced breast cancer progression

Respiratory viral infections (RVI) such as influenza and COVID19 impact the host systemic immune system along with causing deleterious chronic inflammatory responses and respiratory distress. While the role of chronic inflammation in cancer is well-established, the role of RVI on tumorigenesis is poorly defined. To study the role of RVI on breast cancer, we first infected murine respiratory epithelial cells (mRES) with murine sendai virus (mSV), an analog for human parainfluenza virus. These infected mRES were co-cultured with 4T1 murine breast cancer cells in 1:1 dilution on a single 2D plate and also in trans-well format. Both in co-culture and transwell culture we saw a 40- 80% (p<0.05) increased proliferation of breast cancer cells. Similarly, when 4T1 cells were treated with the supernatant collected from infected mRES cells in 1:5 dilution, also demonstrated a 2.3 fold increased breast cancer cell proliferation. The cytokine analysis from the supernatant collected from infected mRES cells demonstrated a 17-23 fold enhanced secretion of alpha/beta-defensins. Direct treatment of alpha-defensin (cyptidin-4, 10 pg/mL) and beta-defensin-3 (mBD3, 20 pg/mL) on 4T1 cells demonstrated enhanced expression of chemokine metastatic receptor, CXCR4 (4.3 fold), angiogenic factor, VEGF (12.8 fold) and cell division favoring factor, CDK2 (8.1 fold). Further, analysis of infected mRES cells demonstrated upregulation of toll-like receptor 2 (TLR2) and NODlike receptor protein 3 (NLRP3) expression. Interesting, co-cultured of infected mRES with syngeneic murine CD4 T cells induced exhaustion phenotype (PD1+ and CTLA4+ ) differentiation of CD4 T cells. Taken together, these data suggest that respiratory viral infections through induction of cancer cell proliferation and inhibiting anti-tumor adaptive immune responses promote breast cancer proliferation.

POLYFUNCTIONAL SARS-CoV-2-SPECIFIC T CELLS PERSIST IN TISSUE OF COVID-19 CONVALESCENTS

Background: T cells play an essential role in SARS-CoV-2 immunity, including in defense against severe COVID-19. However, most studies analyzing SARSCoV- 2-specific T cells have been limited to analysis of blood. Furthermore, the role of T cells in SARS-CoV-2 immunity in pregnant women, which are at disproportionately higher risk of severe COVID-19, is poorly understood. Method(s): Here, we quantitated and deeply phenotyped SARS-CoV-2-specific T cells from convalescent women (n=12) that had mild (non-hospitalized) COVID-19 during pregnancy. Endometrial, maternal blood, and fetal cord blood specimens were procured at term, which ranged from 3 days to 5 months post-infection. SARS-CoV-2-specific T cells were deeply analyzed by CyTOF using a tailored phenotyping panel designed to assess the effector functions, differentiation states, and homing properties of the cells. Result(s): SARS-CoV-2-specific T cells were more abundant in the endometrium than in maternal or fetal cord blood. In a particularly striking example, in one donor sampled 5 months after infection, SARS-CoV-2-specific CD8+ T cells comprised 4.8% of total endometrial CD8+ T cells, while it only reached 1.4% in blood. Endometrial SARS-CoV-2-specific T cells were more frequently of the memory phenotype relative to their counterparts in maternal and fetal cord blood, which harbored higher frequencies of naive T cells. Relative to their counterparts in blood, endometrial SARS-CoV-2-specific T cells exhibited unique phenotypic features, including preferential expression of the T resident memory marker CD69, inflammatory tissue-homing receptor CXCR4, and the activation marker 4-1BB. Endometrial T cells were highly polyfunctional, and could secrete IFNg, TNFa, MIP1b, IL2, and/or IL4 in response to spike peptide stimulation. By contrast, their counterparts in blood preferentially produced the cytolytic effectors perforin and granzyme B. Conclusion(s): Polyfunctional SARS-CoV-2-specific T cells primed by prior exposure to the virus are abundant and persist in endometrial tissue for months after infection. These cells exhibit unique phenotypic features including preferential expression of select chemokine receptors and activation molecules. Compared to their blood counterparts, the effector functions of these cells are more cytokine-driven and less cytolytic. The long-term persistence of these cells in the endometrium may help protect future pregnancies from SARS-CoV-2 re-infection.

Unique Differentiation and Homing Features of T Cells in Individuals with Long Covid

Background: A significant portion of individuals experience persistent symptoms months after SARS-CoV-2 infection, broadly referred to as Long COVID (LC). Although the frequencies of subsets of SARS-CoV-2-specific T cells have been shown to differ in individuals with LC relative to those with complete recovery, a deep dive into phenotypic and functional features of total and SARSCoV- 2-specific T cells from individuals with LC has yet to be performed. Method(s): Here, we used CyTOF to characterize the phenotypes and effector functions of T cells from LIINC cohort. The median age was 46, the cohort was 55.8% female, and 9/43 had been hospitalized. Participants were reported a median of 7 LC symptoms at 8 months. SARS-CoV-2-specific total antibody levels were also measured in concurrent sera. Manual gating was used to define T cell subsets, SPICE analyses for polyfunctionality, T cell clustering for phenotypic features, and linear regression for correlation. Permutation tests, Student's t tests, and Welch's t test were used for statistical analysis. Result(s): SARS-CoV-2 total antibody responses were elevated in the LC group (p=0.043), and correlated with frequencies of SARS-CoV-2-specific T cells in those without LC (r=0.776, p< 0.001) but not those with LC. While the frequencies of total SARS-CoV-2-specific CD4+ and CD8+ T cells were similar between individuals with and without LC, those from individuals without LC tended to be more polyfunctional (co-expressing IFNgamma, TNFalpha, IL2, and/or MIP1beta). CD4+ T cells from individuals with LC harbored higher frequencies of Tcm (p=0.003), Tfh (p=0.037), and Treg subsets (p=0.0412), and preferentially expressed a variety of tissue homing receptors including CXCR4 and CXCR5 (p=0.037). SARS-CoV-2-specific CD4+ T cells producing IL6, albeit rare, were observed exclusively among those with LC (p=0.016). In addition, participants with LC harbored significantly higher frequencies of SARS-CoV-2-specific CD8+ T cells co-expressing exhaustion markers PD1 and CTLA4 (p=0.018). Conclusion(s): Long COVID is characterized by global phenotypic differences in the CD4+ T cell compartment in ways suggesting preferential migration of these cells to inflamed mucosal tissues. Individuals with LC also harbor higher numbers of exhausted SARS-CoV-2-specific CD8+ T cells, potentially implicating viral persistence. Finally, our data additionally suggest that individuals with LC may uniquely exhibit an uncoordinated T cell and antibody response during COVID-19 convalescence.

SARS-CoV-2 Kerala Isolate Spike Protein Induces Cancer Proliferating Markers for Lung and Breast Cancer: An In Silico Approach

Background: Coronavirus disease (COVID 19) has been emerging as a major threat to humans all over the world. Severe Acute Respiratory Syndrome CoronaVirus 2 (nSARS-CoV-2) is the causative agent for the disease resulting in severe acute respiratory illness. Earlier, it took several years to come up with a vaccine or other sorts of treatments for viral diseases. But now with the advent of biotechnology and development of bio-informatic tools, the process has been accelerated. The WHO reports 39,806,488 affected cases and 1,112,208 deaths till today all over the world (17 Oct 2020). nSARS-CoV-2 has a greater influence on people with comorbidities mainly cancer. Objective(s): The study herein attempts to understand the binding affinity of the spike protein of the novel coronavirus with the lung and breast cancer marker proteins by docking and ClusPro analysis. Method(s): The analysis was conducted in reference to hACE2 (human Angiotensin Converting Enzyme 2), the receptor of nSARS-CoV-2. Total 22 different marker proteins were analyzed using ClusPro. Result(s): BRCA1 (Breast Cancer type 1 susceptibility protein) and CXCR4 (a chemokine receptor belong-ing to the G protein coupled receptor family) were found to exhibit higher binding affinities.-73.82 kcal/mol and-66.45 kcal/mol were the global energies they showed upon binding to S protein respective-ly. Conclusion(s): Therefore, novel SARS-CoV-2 has a higher chance of inducing cancer in non-cancerous individuals and aids in cancer acceleration in cancer patients. This poses a threat to cancer patients and immunocompromised individuals. The study can be exploited to identify the optimal drug delivery system for novel SARS CoV2.Copyright © 2022 Bentham Science Publishers.

Molecular interaction between tissue repair via SDF-1/CXCR4 signaling and the inflammatory response in acute myocardial infarction with ST-segment elevation

The inflammatory response/ischemic damage relationship is a prerequisite for the initiation of the process of adaptation of the post-infarction cardiac tissue, in which the SDF-1/CXCR4 signaling plays a central role in tissue repair. This study aimed to investigate the modulation exerted by the SDF-1/CXCR4 axis on the inflammatory response after ST-segment elevation acute myocardial infarction (STEMI). Therefore, we developed Bayesian Networks from microarray (GEO) data and evaluated the expression of transcripts of interest in patients with STEMI by qPCR. In the chronic and anti-inflammatory scenario, we verified a relationship between proteins involved in tissue remodeling and the blockade of apoptotic pathways. The expression levels of the transcripts evaluated were increased in the initial moments after the infarction. In conclusion, the effects promoted by the SDF-1/CXCR4 interaction can be modulated according to the immunological profile, directly influencing its adaptive and cardioprotective effects. Therefore, we believe that students can contribute to the awareness of family and friends about COVID-19 and fake news. © 2023 Multidisciplinary Science Journal. All rights reserved.

[68Ga]Ga-Pentixafor PET/CT uptake due to COVID-19 infection: An incidental finding in a patient with high-grade oligodendroglioma

A 56-year-old woman with new-onset aphasia and mood changes was diagnosed with a left temporal mass. The surgery was done. She was referred for a trial of post-operative study of in vivo evaluation of CXCR4 expression using [68Ga]Ga-Pentixafor (Pars-CixaforTM) PET/CT in high-grade glioma. The imaging from the brain revealed no evidence of tumoral remnant. Furthermore, the patient represented positive COVID-19 PCR about 4 weeks prior to the study. Surprisingly, mild diffuse uptake was noted in the base and periphery of both lungs with ground glass opacities (GGO) and consolidations (SUVmax = 2.60) with CXCR4-avid hilar lymph nodes (SUVmax up to 3.42).Copyright © 2023 The Authors.

Single-cell RNA-sequencing for immune profiling of SARS-CoV2 vaccine response in healthy individuals and patients with precursor plasma cell malignancies

Introduction: Patients with hematological malignancies exhibit inferior response to SARS-CoV2 vaccination, compared to healthy individuals, however little is known about patients with precursor hematological malignancies and the cellular underpinnings of vaccination response. Monoclonal Gammopathy of Undetermined Significance (MGUS) and Smoldering Myeloma (SMM) are plasma cell premalignancies that precede Multiple Myeloma (MM) and exhibit signs of immune dysregulation;they affect approximately 5% of the population over 50 years of age, who remain largely undiagnosed, due to lack of screening. In November 2019, we launched the IMPACT study to characterize the immune response to SARS-CoV2 vaccination in patients with plasma cell dyscrasias and healthy individuals. Methods: We performed single-cell RNA-sequencing on 224 peripheral blood mononuclear cell samples drawn from 118 IMPACT (IRB #20-332) participants with MGUS (n=20), SMM (n=48), or MM (n=24), as well as healthy individuals (n=26). Samples were collected before vaccination and after 2 doses of BNT162b2 (Pfizer-BioNtech) (n=123), mRNA-1273 (Moderna) (n=83) or 1 dose of Ad26.COV2.S (Janssen) (n=14). Results: Overall, we sequenced 2,025,611 cells from 224 samples of 118 patients with MGUS, SMM, MM and healthy individuals pre- and post-vaccination for SARS-CoV2, and profiled 553,082 T-cells, 95,392 B-cells, 74,394 NK cells, 195,371 Monocytes, and 35,236 Dendritic cells (DC). We identified activated clusters of B-cells, NK cells and DCs expressing genes such as CD83, CD69, CXCR4, and genes related to the NF-kB and AP-1 pathways. We compared cell type abundances pre- and post-vaccination within each participant population and found that activated CD83+ cells significantly increased post-vaccination in healthy individuals and patients with MGUS (paired t-test, q < 0.1), but not in patients with SMM or overt MM. At baseline, patients with SMM and MM had significantly fewer memory B-cells and significantly more cytotoxic T-cells and NK cells, compared to healthy individuals (Wilcoxon, q < 0.1), which could partly explain the differences observed post-vaccination. Patients with MM also had significantly higher levels of tolerogenic IL-10-expressing DCs (DC10) at baseline (Wilcoxon, q < 0.1), which could be dampening antigen-specific T-cell responses. Conclusion: We identified a significant expansion of activated B-cell, NK cell and DC subpopulations expressing CD83, CD69 and CXCR4, following vaccination in healthy individuals and patients with MGUS, but less so in patients with SMM and overt MM. Our results provide insight into the cellular mechanisms of immune response to SARS-CoV2 vaccination in healthy individuals and patients with precursor plasma cell malignancies and suggest that asymptomatic individuals with SMM may exhibit inferior response to vaccination.

Alterations in the Covid-19 - Associated Proteome Relative to Length of Hospital Stay

RATIONALE: The proteomic responses of hospitalized patients with SARS Co-V-2 infection may provide insight into risk, time course, and mechanisms associated with this infection. We used a high throughput proteomic platform to examine proteins that were differentially expressed relative to the length of hospital stay (LOS). METHOD:26 patients, hospitalized with SARS CoV-2 infection (mean age 48 yrs, 44% women) had blood samples obtained within 72 hours of admission. Initial plasma samples were analyzed from patients who were hospitalized for < 3 days (n=6), < 7days (n=12) and > 7 days (n=8) of LOS and compared to healthy controls (HC, n=8). Samples were analyzed with the modified aptamer-based array (SomaScan) that measures more than 7,000 human proteins representing different molecular pathways and gene families. Differentially regulated proteins with > 1.5 fold change and a false discovery rate of 5% were analyzed using the Ingenuity Pathway Analysis (IPA). Unique protein categories associated with LOS were assessed. RESULT: Compared to HC, differentially expressed proteins were detected among the 3 groups: 461 at < 3 days, 1,635 proteins at < 7 days and 1,738 proteins in >7 days. 407 proteins were common among all hospitalized COVID 19 individuals independent of LOS and 12, 250 and 361 proteins were uniquely present at < 3 days, < 7 days and > 7 days respectively compared to HC. The table below demonstrates the top highly enriched canonical pathway, molecular function and upstream regulator of differentially expressed proteins. The temporal sequence of these protein networks varied with LOS. Representative examples include early responses;platelet membrane glycoprotein GP6 signaling pathway that involves the FcR gamma-chain and the Src kinases linked to platelet aggregation, signaling involved in T cell receptor-mediated IL-2 production (TEC kinase). Less than 7 days include diacylglycerol associated with T cell activation, carnitine palmitoyltransferase associated with mitochondrial beta-oxidation of long chain fatty acids. CXCR4 a receptor for stromal -cell derived factor 1 and associated with COVID-19 prognosis. Late responses after 7 days include pathways involved in remodeling of epithelial adherens junctions. CONCLUSIONS : A high throughput proteomic approach provides insight into the dynamic regulation of protein pathways associated with the progression of SARS-Co-V2 infection. This may provide additional insight into risk and mechanisms associated with outcomes in COVID. (Table Presented).

SARCOMA MIELOIDE NA LEUCEMIA MIELOIDE AGUDA EM REMISSÃO: RELATO DE CASO

Introdução: O sarcoma mieloide tem incidência variável. Um caso de sarcoma mieloide (SM) em paciente com leucemia mieloide aguda (LMA) em tratamento com doença residual mínima (DRM) negativa será apresentado abaixo, já que preocupa as equipes médicas e se torna desafiador. Relato de caso: Paciente feminina, 21 anos, previamente hígida, queixa de astenia e dor de garganta. Procurou atendimento com 2 dias de evolução, sendo afastada infecção por SARS-CoV-2 e liberada com antibióticos. Cinco dias após houve piora dos sintomas, com astenia e surgimento de linfonodomegalias cervicais. Retornou para atendimento e laboratoriais mostraram: Hb 8,2, Ht 25,2, VCM 93, Leucócitos 90.230, blastos 88%, neutrófilos 1%, eosinófilos 1%, linfócitos 10%, plaquetas 64.000. Internada, foi submetida a análise de medula óssea (MO) que evidenciou infiltração na totalidade por blastos;imunofenotipagem (IFT) indicou LMA com diferenciação monocítica;cariótipo com trissomia do 8. Após citorredução com hidroxiureia, foi submetida a indução com Ara-C e idarrubicina (7+3), apresentando remissão morfológica em 14 dias. Seguiu esquema de consolidação com altas doses de citarabina, com DRM negativa antes do segundo ciclo. Às vésperas da terceira consolidação chega com inúmeras lesões nodulares violáceas. Biópsia da lesão gera imunohistoquímica (IHQ) compatível com sarcoma mieloide com os marcadores: mieloperoxidase, CD68 (KP1), CD33, CD34, CD4 e CD3 positivos e CD20 negativo. Com medula e sangue periférico (SP) negativos, optado por realizar mitoxantrona, etoposide e citarabina, levando a remissão da doença. Discussão e conclusão: De incidência não estabelecida, chegando até 30% de todos os casos de LMA, o SM, conforme a OMS, carecteriza-se pela massa tumoral extramedular formada por blastos mieloides com ou sem maturação. Mas incidente a partir das LMA com diferenciação monocítica, o prognóstico é incerto já que os estudos mostram de desfechos inferiores de sobrevida e tempo livre de doença até não haver mudanças entre as variáveis quando comparados com os desfechos da LMA. O SM possui uma variedade de apresentações: SM sem evidência de leucemia em SP ou MO, SM concomitante a LMA, SM associado a síndrome mielodisplásica, mieloprolifaração ou leucemia mieloide crônica e SM com LMA em remissão. Sendo a pele o principal órgão acometido a migração das células blásticas ainda não é bem compreendida, mas se evidencia relação com a expressão de CD11b, CD56 e da proteína CXCR4 mais frequente nos blastos mielomonocíticos. O diagnóstico deve ser realizado através de biópsia da lesão seguido de IHQ que inclua os marcadores CD33, CD117, MPO, CD34, CD43, CD68 (KP1), CD3, geralmente positivos. Dessa forma pode-se realizar diagnóstico diferencial com outras lesões de pele, principalmente com neoplasia de células dendríticas plasmocitoides blásticas. No estadiamento se fazem importantes os exames de imagem, preferencialmente, PET-CT, e a análise da MO, já que esta última será o critério avaliado para realização do transplante de medula óssea. O tratamento varia de acordo com a concomitância com outras neoplasias hematológicas mas, de maneira geral, os protocolos que incluem Ara-C oferecem remissão completa das lesões de pele. Diante disso, ressalta-se a importância de realizar um bom diagnóstico de forma e conhecer a patologia de forma a tranquilizar a equipe médica em relação aos desfechos.

Ligand-based Modeling of CXC Chemokine Receptor 4 and Identification of Inhibitors of Novel Chemotypes as Potential Leads towards New Anti- COVID-19 Treatments.

BACKGROUND: Chemokines are involved in several human diseases and different stages of COVID-19 infection. They play a critical role in the pathophysiology of the associated acute respiratory disease syndrome, a major complication leading to death among COVID-19 patients. In particular, CXC chemokine receptor 4 (CXCR4) was found to be highly expressed in COVID-19 patients. METHODS: We herein describe a computational workflow based on combining pharmacophore modeling and QSAR analysis towards the discovery of novel CXCR4 inhibitors. Subsequent virtual screening identified two promising CXCR4 inhibitors from the National Cancer Institute (NCI) list of compounds. The most active hit showed in vitro IC50 value of 24.4 µM. CONCLUSION: These results proved the validity of the QSAR model and associated pharmacophore models as means to screen virtual databases for new CXCR4 inhibitors as leads for the development of new COVID-19 therapies.

Longitudinal Transcriptional Analysis of Peripheral Blood Leukocytes in COVID Convalescent Donors

Introduction Severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) can induce a strong host immune response. Several groups have investigated the course of antibody responses in patients recovering from SARS-CoV-2 infections but little is known about the recovery of cellular immunity. This study investigated the cellular immune response in people who had recovered from SARS-CoV2 infection. Methods 162 coronavirus disease 2019 (COVID-19) convalescent plasma donors (CCD) and 40 healthy donor (HD) controls were enrolled prospectively in an IRB-approved protocol (Clinical Trials Number: NCT04360278) and provided written informed consent to participate in the study. Using the nCounter platform and host response panel with 785 genes across more than 50 pathways, we compared transcriptomic profiles on RNA samples obtained from the peripheral blood leukocytes of these 162 CCD and 40 HD. Additionally, in 69 of the 162 CCD samples, we evaluated transcriptomic trends at more than one-time point during the convalescent period. Results Age, sex, ethnicity, and body mass index distributions were similar among the CCD and HD. With respect to baseline complete blood counts, hemoglobin, platelets, and absolute basophil and eosinophil counts, all were similar among CCD and HD (Table 1). However, despite sample collections occurring several days after convalescence, mean counts for absolute neutrophil counts, absolute monocyte counts, and absolute lymphocyte counts were significantly higher among CCD compared to HD. 30-90 days after diagnosis, 19 of 773 genes differed (FDR < 0.05) between the average CCD and HD samples. Up-regulated genes included MAFB, CTLA4, PTGS2, and the chemokine signaling genes CXCR4, CXCL5, CXCL2 and CCR4. Down-regulated genes included PTGER2, CASP8, and the interleukins IL36A, IL31, IL20 and IL21 (Figure 1 a,b). Differential gene expression persisted for months. At 90-120 days, 13 genes were differentially regulated, including again MAFB CXCR4, PTGS2, CXCL2 and PTGER2, plus SMAD4. At 120-150 days post-diagnosis, 58 genes were differentially expressed (FDR < 0.05) compared to HD. Pathways with up-regulated genes included Treg differentiation, type III interferon signaling and chemokine signaling. 150-360 days post-diagnosis, 4 genes remained up-regulated on average (FDR < 0.05): PTGS2, PIK3CR, CXCL1 and SMAD4 (Figure 1 c,d). Individual patients varied considerably from the mean trend. Scoring samples by their similarity to the gene expression profile of the mean HD sample, 21 CCD samples from 20 unique patients (12%) were identified as highly perturbed from HD. 84% of these highly perturbed samples were collected > 90 days post-diagnosis. Of these 21 samples, 6 were distinguished by > 2-fold up-regulation of a cluster of interleukin and type-1 interferon genes (Figure 2). Conclusions Overall, our study identified important gene expression trends in CCD compared to HD in the post-acute period. The changes varied with time and among donors. As the expression of T-cell inhibitory molecule CTLA4 fell, the number of differentially expressed increased with the most marked changes occurring 120 to 150 days post-diagnosis in genes in chemokine signaling, type III interferon signaling and Treg pathways. Persistent alterations in inflammatory pathways and T-cell activation/exhaustion markers for months after active infection may help shed light on the pathophysiology of a prolonged post-viral syndrome observed in individuals following recovery from COVID-19 infection. Our data may serve as the basis for risk modification strategies in the period of active infection. Future studies may inform the ability to identify druggable targets involving these pathways to mitigate the long-term effects of COVID-19 infection. [Formula presented] Disclosures: Danaher: NanoString Technologies: Current Employment, Current holder of individual stocks in a privately-held company.

Distinctive features of SARS-CoV-2-specific T cells predict recovery from severe COVID-19.

Although T cells are likely players in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity, little is known about the phenotypic features of SARS-CoV-2-specific T cells associated with recovery from severe coronavirus disease 2019 (COVID-19). We analyze T cells from 34 individuals with COVID-19 with severity ranging from mild (outpatient) to critical, culminating in death. Relative to individuals who succumbed, individuals who recovered from severe COVID-19 harbor elevated and increasing numbers of SARS-CoV-2-specific T cells capable of homeostatic proliferation. In contrast, fatal COVID-19 cases display elevated numbers of SARS-CoV-2-specific regulatory T cells and a time-dependent escalation in activated bystander CXCR4+ T cells, as assessed by longitudinal sampling. Together with the demonstration of increased proportions of inflammatory CXCR4+ T cells in the lungs of individuals with severe COVID-19, these results support a model where lung-homing T cells activated through bystander effects contribute to immunopathology, whereas a robust, non-suppressive SARS-CoV-2-specific T cell response limits pathogenesis and promotes recovery from severe COVID-19.

Identify. Quantify. Predict. Why Immunologists Should Widely Use Molecular Imaging for Coronavirus Disease 2019.

Molecular imaging using PET/CT or PET/MRI has evolved from an experimental imaging modality at its inception in 1972 to an integral component of diagnostic procedures in oncology, and, to lesser extent, in cardiology and neurology, by successfully offering in-vivo imaging and quantitation of key pathophysiological targets or molecular signatures, such as glucose metabolism in cancerous disease. Apart from metabolism probes, novel radiolabeled peptide and antibody PET tracers, including radiolabeled monoclonal antibodies (mAbs) have entered the clinical arena, providing the in-vivo capability to collect target-specific quantitative in-vivo data on cellular and molecular pathomechanisms on a whole-body scale, and eventually, extract imaging biomarkers possibly serving as prognostic indicators. The success of molecular imaging in mapping disease severity on a whole-body scale, and directing targeted therapies in oncology possibly could translate to the management of Coronavirus Disease 2019 (COVID-19), by identifying, localizing, and quantifying involvement of different immune mediated responses to the infection with SARS-COV2 during the course of acute infection and possible, chronic courses with long-term effects on specific organs. The authors summarize current knowledge for medical imaging in COVID-19 in general with a focus on molecular imaging technology and provide a perspective for immunologists interested in molecular imaging research using validated and immediately available molecular probes, as well as possible future targets, highlighting key targets for tailored treatment approaches as brought up by key opinion leaders.

Discovery of HIV entry inhibitors via a hybrid CXCR4 and CCR5 receptor pharmacophore-based virtual screening approach.

Chemokine receptors are key regulators of cell migration in terms of immunity and inflammation. Among these, CCR5 and CXCR4 play pivotal roles in cancer metastasis and HIV-1 transmission and infection. They act as essential co-receptors for HIV and furnish a route to the cell entry. In particular, inhibition of either CCR5 or CXCR4 leads very often the virus to shift to a more virulent dual-tropic strain. Therefore, dual receptor inhibition might improve the therapeutic strategies against HIV. In this study, we aimed to discover selective CCR5, CXCR4, and dual CCR5/CXCR4 antagonists using both receptor- and ligand-based computational methods. We employed this approach to fully incorporate the interaction attributes of the binding pocket together with molecular dynamics (MD) simulations and binding free energy calculations. The best hits were evaluated for their anti-HIV-1 activity against CXCR4- and CCR5-specific NL4.3 and BaL strains. Moreover, the Ca2+ mobilization assay was used to evaluate their antagonistic activity. From the 27 tested compounds, three were identified as inhibitors: compounds 27 (CCR5), 6 (CXCR4) and 3 (dual) with IC50 values ranging from 10.64 to 64.56 µM. The binding mode analysis suggests that the active compounds form a salt bridge with the glutamates and π-stacking interactions with the aromatic side chains binding site residues of the respective co-receptor. The presented hierarchical virtual screening approach provides essential aspects in identifying potential antagonists in terms of selectivity against a specific co-receptor. The compounds having multiple heterocyclic nitrogen atoms proved to be relatively more specific towards CXCR4 inhibition as compared to CCR5. The identified compounds serve as a starting point for further development of HIV entry inhibitors through synthesis and quantitative structure-activity relationship studies.