Rabbani, MY;Rappaport, J;Gupta, MK;
PMID: 35203260 | DOI: 10.3390/cells11040611
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is an extremely contagious disease whereby the virus damages the host's respiratory tract via entering through the ACE2 receptor. Cardiovascular disorder is being recognized in the majority of COVID-19 patients; yet, the relationship between SARS-CoV-2 and heart failure has not been established. In the present study, SARS-CoV-2 infection was induced in the monkey model. Thereafter, heart tissue samples were collected, and pathological changes were analyzed in the left ventricular tissue by hematoxylin and eosin, trichrome, and immunohistochemical staining specific to T lymphocytes and macrophages. The findings revealed that SARS-CoV-2 infection induces several pathological changes in the heart, which cause cardiomyocyte disarray, mononuclear infiltrates of inflammatory cells, and hypertrophy. Furthermore, collagen-specific staining showed the development of cardiac fibrosis in the interstitial and perivascular regions in the hearts of infected primates. Moreover, the myocardial tissue samples displayed multiple foci of inflammatory cells positive for T lymphocytes and macrophages within the myocardium. These findings suggest the progression of the disease, which can lead to the development of severe complications, including heart failure. Additionally, SARS-CoV-2 antigen staining detected the presence of virus particles in the myocardium. Thus, we found that SARS-CoV-2 infection is characterized by an exaggerated inflammatory immune response in the heart, which possibly contributes to myocardial remodeling and subsequent fibrosis.
McMahan, K;Giffin, V;Tostanoski, LH;Chung, B;Siamatu, M;Suthar, MS;Halfmann, P;Kawaoka, Y;Piedra-Mora, C;Jain, N;Ducat, S;Kar, S;Andersen, H;Lewis, MG;Martinot, AJ;Barouch, DH;
PMID: 35313451 | DOI: 10.1016/j.medj.2022.03.004
The SARS-CoV-2 Omicron (B.1.1.529) variant has proven highly transmissible and has outcompeted the Delta variant in many regions of the world. Early reports have also suggested that Omicron may result in less severe clinical disease in humans. Here we show that Omicron is less pathogenic than prior SARS-CoV-2 variants in Syrian golden hamsters.Hamsters were inoculated with either SARS-CoV-2 Omicron or other SARS-CoV-2 variants. Animals were followed for weight loss, and upper and lower respiratory tract tissues were assessed for viral loads and histopathology.Infection of hamsters with the SARS-CoV-2 WA1/2020, Alpha, Beta, or Delta strains led to 4-10% weight loss by day 4 and 10-17% weight loss by day 6. In contrast, infection of hamsters with two different Omicron challenge stocks did not result in any detectable weight loss, even at high challenge doses. Omicron infection led to substantial viral replication in both the upper and lower respiratory tracts but demonstrated lower viral loads in lung parenchyma and reduced pulmonary pathology compared with WA1/2020 infection.These data suggest that the SARS-CoV-2 Omicron variant may result in robust upper respiratory tract infection but less severe lower respiratory tract clinical disease compared with prior SARS-CoV-2 variants.Funding for this study was provided by NIH grant CA260476, the Massachusetts Consortium for Pathogen Readiness, the Ragon Institute, and the Musk Foundation.
McGonagle, D;Kearney, M;O'Regan, A;O'Donnell, J;Quartuccio, L;Watad, A;Bridgewood, C;
| DOI: 10.1016/S2665-9913(21)00322-2
In patients with moderate-to-severe COVID-19 pneumonia, an aberrant post-viral alveolitis with excessive inflammatory responses and immunothrombosis underpins use of immunomodulatory therapy (eg, corticosteroids and interleukin-6 receptor antagonism). By contrast, immunosuppression in individuals with mild COVID-19 who do not require oxygen therapy or in those with critical disease undergoing prolonged ventilation is of no proven benefit. Furthermore, a window of opportunity is thought to exist for timely immunosuppression in patients with moderate-to-severe COVID-19 pneumonia shortly after clinical presentation. In this Viewpoint, we explore the shortcomings of a universal immunosuppression approach in patients with moderate-to-severe COVID-19 due to disease heterogeneity related to ongoing SARS-CoV-2 replication, which can manifest as RNAaemia in some patients treated with immunotherapy. By contrast, immunomodulatory therapy has overall benefits in patients with rapid SARS-CoV-2 clearance, via blunting of multifaceted, excessive innate immune responses in the lungs, potentially uncontrolled T-cell responses, possible autoimmune responses, and immunothrombosis. We highlight this therapeutic dichotomy to better understand the immunopathology of moderate-to-severe COVID-19, particularly the role of RNAaemia, and to refine therapy choices.
Kozicky LK, Menzies SC, Hotte N, Madsen KL, Sly LM.
PMID: 31054259 | DOI: 10.1002/eji.201848014
Intravenous immunoglobulin (IVIg) is used to treat immune-mediated diseases but its mechanism of action is poorly understood. We have reported that co-treatment with IVIg and lipopolysaccharide activates macrophages to produce large amounts of anti-inflammatory IL-10 in vitro. Thus, we asked whether IVIg-treated macrophages or IVIg could reduce intestinal inflammation in mice during dextran sulfate sodium (DSS)-induced colitis by inducing macrophage IL-10 production in vivo. Adoptive transfer of IVIg-treated macrophages reduces intestinal inflammation in mice and collagen accumulation post-DSS. IVIg treatment also reduces DSS-induced intestinal inflammation and its activity is dependent on the Fc portion of the antibody. Ex vivo, IVIg induces IL-10 production and reduces IL-12/23p40 and IL-1β production in colon explant cultures. Co-staining tissues for mRNA, we demonstrate that macrophages are the source of IL-10 in IVIg-treated mice; and using IL-10-GFP reporter mice, we demonstrate that IVIg induces IL-10 production by intestinal macrophages. Finally, IVIg-mediated protection is lost in mice deficient in macrophage IL-10 production (LysMcre+/- IL-10fl/fl mice). Together, our data demonstrate a novel, in vivo mechanism of action for IVIg. IVIg-treated macrophages or IVIg could be used to treat people with intestinal inflammation and may be particularly useful for people with inflammatory bowel disease, who are refractory to therapy.
Neutrophil-epithelial interactions augment infectivity and pro-inflammatory responses to SARS-CoV-2 infection
bioRxiv : the preprint server for biology
Calvert, BA;Quiroz, EJ;Lorenzana, Z;Doan, N;Kim, S;Senger, CN;Wallace, WD;Salomon, MP;Henley, JE;Ryan, AL;
PMID: 34401877 | DOI: 10.1101/2021.08.09.455472
In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre-existing co-morbidities, correlating to incidence of severe COVID-19, are associated with chronic airway neutrophilia and examination of COVID-19 lung tissue revealed a series of epithelial pathologies associated with infiltration and activation of neutrophils. To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory response to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. We discovered that SARS-CoV-2 infection of the airway epithelium alone does not result in a notable release of pro-inflammatory cytokines, however in the presence of neutrophils, the inflammatory response is both polarized and significantly augmented, epithelial barrier integrity in impaired and viral load of the airway epithelium increased. This study reveals a key role for neutrophil-epithelial interactions in determining inflammation, infectivity, and outcomes in response to SARS-CoV-2 infection.We have developed a model to study neutrophil-epithelial interactions which better reflects the in vivo situation than monocultures Neutrophils significantly augment SARS-CoV-2 mediated, pro-inflammatory cytokine release from the epithelium indicating a key interactionSARS-CoV-2 infection leads to a polarized inflammatory response in differentiated airway epitheliumDisruption of the epithelial barrier via addition of neutrophils or cytokines leads to increased infectionStudy reveals a key role for neutrophil-epithelial interactions in determining outcome/infectivity.
SARS-CoV-2 Infects Endothelial Cells In Vivo and In Vitro
Frontiers in cellular and infection microbiology
Liu, F;Han, K;Blair, R;Kenst, K;Qin, Z;Upcin, B;Wörsdörfer, P;Midkiff, CC;Mudd, J;Belyaeva, E;Milligan, NS;Rorison, TD;Wagner, N;Bodem, J;Dölken, L;Aktas, BH;Vander Heide, RS;Yin, XM;Kolls, JK;Roy, CJ;Rappaport, J;Ergün, S;Qin, X;
PMID: 34307198 | DOI: 10.3389/fcimb.2021.701278
SARS-CoV-2 infection can cause fatal inflammatory lung pathology, including thrombosis and increased pulmonary vascular permeability leading to edema and hemorrhage. In addition to the lung, cytokine storm-induced inflammatory cascade also affects other organs. SARS-CoV-2 infection-related vascular inflammation is characterized by endotheliopathy in the lung and other organs. Whether SARS-CoV-2 causes endotheliopathy by directly infecting endothelial cells is not known and is the focus of the present study. We observed 1) the co-localization of SARS-CoV-2 with the endothelial cell marker CD31 in the lungs of SARS-CoV-2-infected mice expressing hACE2 in the lung by intranasal delivery of adenovirus 5-hACE2 (Ad5-hACE2 mice) and non-human primates at both the protein and RNA levels, and 2) SARS-CoV-2 proteins in endothelial cells by immunogold labeling and electron microscopic analysis. We also detected the co-localization of SARS-CoV-2 with CD31 in autopsied lung tissue obtained from patients who died from severe COVID-19. Comparative analysis of RNA sequencing data of the lungs of infected Ad5-hACE2 and Ad5-empty (control) mice revealed upregulated KRAS signaling pathway, a well-known pathway for cellular activation and dysfunction. Further, we showed that SARS-CoV-2 directly infects mature mouse aortic endothelial cells (AoECs) that were activated by performing an aortic sprouting assay prior to exposure to SARS-CoV-2. This was demonstrated by co-localization of SARS-CoV-2 and CD34 by immunostaining and detection of viral particles in electron microscopic studies. Moreover, the activated AoECs became positive for ACE-2 but not quiescent AoECs. Together, our results indicate that in addition to pneumocytes, SARS-CoV-2 also directly infects mature vascular endothelial cells in vivo and ex vivo, which may contribute to cardiovascular complications in SARS-CoV-2 infection, including multipleorgan failure.
Laboratory investigation; a journal of technical methods and pathology
Granai, M;Warm, V;Vogelsberg, A;Milla, J;Greif, K;Vogel, U;Bakchoul, T;Rosenberger, P;Quintanilla-Martinez, L;Schürch, C;Klingel, K;Fend, F;Bösmüller, H;
PMID: 37224922 | DOI: 10.1016/j.labinv.2023.100179
In critically ill SARS-CoV-2 infected patients, early leukocyte recruitment to the respiratory system was found to be orchestrated by leukocyte trafficking molecules accompanied by massive secretion of pro-inflammatory cytokines and hypercoagulability. Our study aimed to explore the interplay between leukocyte activation and pulmonary endothelium in different disease stages of fatal COVID-19. Our study comprised 10 COVID-19 post-mortem lung specimens and 20 control lung samples (5 ARDS, 2 viral pneumonia, 3 bacterial pneumonia, and 10 normal) which were stained for antigens representing the different steps of leucocyte migration: E-selectin, P-selectin, PSGL-1, ICAM1, VCAM1, and CD11b. Image analysis software QuPath was used for quantification of positive leukocytes (PSGL-1 and CD11b) and endothelium (E-selectin, P-selectin, ICAM1, VCAM1). Expression of IL-6 and IL-1ß was quantified by qRT-PCR. Expression of P-selectin and PSGL-1 was strongly increased in the COVID-19 cohort compared to all control groups (ratio =17,23, p<0,0001; ratio=2,75, p<0,0001 respectively). Importantly, P-selectin was found in endothelial cells and associated with aggregates of activated platelets adherent to the endothelial surface in COVID-19 cases. In addition, PSGL-1 staining disclosed positive perivascular leucocyte cuffs, reflecting capillaritis. Moreover, CD11b showed a strongly increased positivity in COVID-19 compared to all controls (ratio=2,89; p=0,0002), indicating a proinflammatory immune microenvironment. Of note, CD11b exhibited distinct staining patterns at different stages of COVID-19 disease. Only in cases with very short disease course, high levels of IL-1ß and IL-6 mRNA were observed in lung tissue. The striking upregulation of PSGL-1 and P-selectin reflects the activation of this receptor-ligand pair in COVID-19, increasing the efficiency of initial leucocyte recruitment, thus promoting tissue damage and immunothrombosis. Our results show that endothelial activation and unbalanced leukocyte migration play a central role in COVID-19 involving the P-selectin-PSGL-1 axis.
Emerging microbes & infections
Li, C;Song, W;Chan, JF;Chen, Y;Liu, F;Ye, Z;Lam, AH;Cai, J;Lee, AC;Wong, BH;Chu, H;Lung, DC;Sridhar, S;Chen, H;Zhang, AJ;Yuen, KY;
PMID: 37122119 | DOI: 10.1080/22221751.2023.2207678
SummaryIntranasal infection of newly-weaned Syrian hamsters by SARS-CoV-2 Omicron variants can lead to brain inflammation and neuron degeneration with detectable low viral load and sparse expression of viral nucleoprotein.AbstractChildren infected by SARS-CoV-2 Omicron variant may develop neurological complications. To study the pathogenesis in the growing brain, we intranasally challenged newly-weaned or mature hamsters with SARS-CoV-2 Omicron BA.2, BA.5 or Delta variant. Omicron BA.2 and Delta infection produced a significantly lower viral load in the lung tissues of newly-weaned than mature hamsters despite comparable histopathological damages. Newly-weaned hamsters had higher brain viral load, significantly increased cerebrospinal fluid concentration of TNF-α and CXCL10 and inflammatory damages including mild meningitis and parenchymal vascular congestion, despite sparse expression of nucleocapsid antigen in brain cells. Furthermore, 63.6% (28/44) of all SARS-CoV-2 infected newly-weaned hamsters showed microgliosis in olfactory bulb, cerebral cortex and hippocampus. In infected mature hamsters, microgliosis were observed mainly in olfactory bulb and olfactory cortex of 35.3% (12/34) of their brains. Neuronal degeneration was found in 75% (33/44) of newly-weaned hamsters affecting multiple regions including olfactory bulb, olfactory cortex, midbrain cortex and hippocampus, while such changes were mainly observed in hippocampus of mature hamsters. Importantly, similar brain histopathology was observed in Omicron BA.5 infected newly-weaned hamsters. Our study suggested that SARS-CoV-2 may affect the brain at young age. This kind of brain involvement and histological changes are not virus variant or subvariant specific. Incidentally, moderate amount of eosinophilic infiltration was observed in the mucosa of nasal turbinate and trachea of newly-weaned hamsters infected by Omicron BA.2 and BA.5 but not Delta variant. This histological finding is consistent with the higher incidence of laryngotracheobronchitis in young children infected by the Omicron variant.
Kaewborisuth, C;Wanitchang, A;Koonpaew, S;Srisutthisamphan, K;Saenboonrueng, J;Im-Erbsin, R;Inthawong, M;Sunyakumthorn, P;Thaweerattanasinp, T;Tanwattana, N;Jantraphakorn, Y;Reed, MC;Lugo-Roman, LA;Hunsawong, T;Klungthong, C;Jones, AR;Fernandez, S;Teeravechyan, S;Lombardini, ED;Jongkaewwattana, A;
PMID: 35632541 | DOI: 10.3390/vaccines10050786
Virus-like particles (VLPs) are highly immunogenic and versatile subunit vaccines composed of multimeric viral proteins that mimic the whole virus but lack genetic material. Due to the lack of infectivity, VLPs are being developed as safe and effective vaccines against various infectious diseases. In this study, we generated a chimeric VLP-based COVID-19 vaccine stably produced by HEK293T cells. The chimeric VLPs contain the influenza virus A matrix (M1) proteins and the SARS-CoV-2 Wuhan strain spike (S) proteins with a deletion of the polybasic furin cleavage motif and a replacement of the transmembrane and cytoplasmic tail with that of the influenza virus hemagglutinin (HA). These resulting chimeric S-M1 VLPs, displaying S and M1, were observed to be enveloped particles that are heterogeneous in shape and size. The intramuscular vaccination of BALB/c mice in a prime-boost regimen elicited high titers of S-specific IgG and neutralizing antibodies. After immunization and a challenge with SARS-CoV-2 in K18-hACE2 mice, the S-M1 VLP vaccination resulted in a drastic reduction in viremia, as well as a decreased viral load in the lungs and improved survival rates compared to the control mice. Balanced Th1 and Th2 responses of activated S-specific T-cells were observed. Moderate degrees of inflammation and viral RNA in the lungs and brains were observed in the vaccinated group; however, brain lesion scores were less than in the PBS control. Overall, we demonstrate the immunogenicity of a chimeric VLP-based COVID-19 vaccine which confers strong protection against SARS-CoV-2 viremia in mice.
Annals of Diagnostic Pathology
Mezache, L;Nuovo, G;Suster, D;Tili, E;Awad, H;Radwański, P;Veeraraghavan, R;
| DOI: 10.1016/j.anndiagpath.2022.151983
Cardiac manifestations are common in severe COVID-19. This study compared the histologic, viral, and molecular findings in cardiac tissue in fatal COVID-19 (n = 11) and controls (n = 11). In situ hybridization (SARS-CoV2 RNA) and immunohistochemistry for viral proteins and the host response were quantified for the samples and compared with qRTPCR and Western blot data. Control hearts showed a high resident population of macrophages that had variable ACE2 expression. Cardiac ACE2 expression was 10× greater in the heart tissues of cases and controls with obesity or type II diabetes. Multifocal endothelial cell swelling and degeneration, perivascular edema plus microvascular thrombi were unique to the cases. SARS-CoV2 RNA and nucleocapsid protein were rarely detected in situ in any COVID-19 heart. However, in each case abundant SARS-CoV-2 spike protein was evident. Co-expression experiments showed that the spike protein localized mostly to the ACE2+ interstitial macrophages/pericytes that were activated as evidenced by increased IL6 and TNFα expression. Western blots confirmed the presence of the viral spike protein, but not the nucleocapsid protein, in the cardiac homogenates. The intercalated disc proteins connexin 43, the primary cardiac gap junction protein, and NaV1.5, the predominant cardiac sodium channel, each showed marked lateral migration in the myocytes in the cases, which would increase the risk of reentrant arrhythmias. It is concluded that the viral spike protein, endocytosed by macrophages/pericytes, can induce a myocarditis with the possibility of conduction dysfunction due to abnormal localization of key intercalated disc proteins.
Chiba, S;Kiso, M;Nakajima, N;Iida, S;Maemura, T;Kuroda, M;Sato, Y;Ito, M;Okuda, M;Yamada, S;Iwatsuki-Horimoto, K;Watanabe, T;Imai, M;Armbrust, T;Baric, RS;Halfmann, PJ;Suzuki, T;Kawaoka, Y;
PMID: 35100870 | DOI: 10.1128/mbio.03044-21
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide since December 2019, causing coronavirus disease 2019 (COVID-19). Although vaccines for this virus have been developed rapidly, repurposing drugs approved to treat other diseases remains an invaluable treatment strategy. Here, we evaluated the inhibitory effects of drugs on SARS-CoV-2 replication in a hamster infection model and in in vitro assays. Favipiravir significantly suppressed virus replication in hamster lungs. Remdesivir inhibited virus replication in vitro, but was not effective in the hamster model. However, GS-441524, a metabolite of remdesivir, effectively suppressed virus replication in hamsters. Co-administration of favipiravir and GS-441524 more efficiently reduced virus load in hamster lungs than did single administration of either drug for both the prophylactic and therapeutic regimens; prophylactic co-administration also efficiently inhibited lung inflammation in the infected animals. Furthermore, pretreatment of hamsters with favipiravir and GS-441524 effectively protected them from virus transmission via respiratory droplets upon exposure to infected hamsters. Repurposing and co-administration of antiviral drugs may help combat COVID-19. IMPORTANCE During a pandemic, repurposing drugs that are approved for other diseases is a quick and realistic treatment option. In this study, we found that co-administration of favipiravir and the remdesivir metabolite GS-441524 more effectively blocked SARS-CoV-2 replication in the lungs of Syrian hamsters than either favipiravir or GS-441524 alone as part of a prophylactic or therapeutic regimen. Prophylactic co-administration also reduced the severity of lung inflammation. Moreover, co-administration of these drugs to naive hamsters efficiently protected them from airborne transmission of the virus from infected animals. Since both drugs are nucleotide analogs that interfere with the RNA-dependent RNA polymerases of many RNA viruses, these findings may also help encourage co-administration of antivirals to combat future pandemics.
SARS-CoV-2, myocardial injury and inflammation: insights from a large clinical and autopsy study
Clinical research in cardiology : official journal of the German Cardiac Society
Dal Ferro, M;Bussani, R;Paldino, A;Nuzzi, V;Collesi, C;Zentilin, L;Schneider, E;Correa, R;Silvestri, F;Zacchigna, S;Giacca, M;Metra, M;Merlo, M;Sinagra, G;
PMID: 34282465 | DOI: 10.1007/s00392-021-01910-2
Despite growing evidence about myocardial injury in hospitalized COronaVIrus Disease 2019 (COVID-19) patients, the mechanism behind this injury is only poorly understood and little is known about its association with SARS-CoV-2-mediated myocarditis. Furthermore, definite evidence of the presence and role of SARS-CoV-2 in cardiomyocytes in the clinical scenario is still lacking.We histologically characterized myocardial tissue of 40 patients deceased with severe SARS-CoV-2 infection during the first wave of the pandemic. Clinical data were also recorded and analyzed. In case of findings supportive of myocardial inflammation, histological analysis was complemented by RT-PCR and immunohistochemistry for SARS-CoV-2 viral antigens and in situ RNA hybridization for the detection of viral genomes.Both chronic and acute myocardial damage was invariably present, correlating with the age and comorbidities of our population. Myocarditis of overt entity was found in one case (2.5%). SARS-CoV-2 genome was not found in the cardiomyocytes of the patient with myocarditis, while it was focally and negligibly present in cardiomyocytes of patients with known viral persistence in the lungs and no signs of myocardial inflammation. The presence of myocardial injury was not associated with myocardial inflammatory infiltrates.In this autopsy cohort of COVID-19 patients, myocarditis is rarely found and not associated with SARS-CoV-2 presence in cardiomyocytes. Chronic and acute forms of myocardial damage are constantly found and correlate with the severity of COVID-19 disease and pre-existing comorbidities.
