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1.
Article in English | MEDLINE | ID: mdl-39082483

ABSTRACT

Hepatic injuries in COVID-19 are not yet fully understood and indirect pathways (without viral replication in the liver) have been associated with the activation of vascular mechanisms of liver injury in humans infected with SARS-CoV-2. Golden Syrian hamsters are an effective model for experimental reproduction of moderate and self-limiting lung disease during SARS-CoV-2 infection. As observed in humans, this experimental model reproduces lesions of bronchointerstitial pneumonia and pulmonary vascular lesions, including endotheliitis (attachment of lymphoid cells to the luminal surface of endothelium). Extrapulmonary vascular lesions are well documented in COVID-19, but such extrapulmonary vascular lesions have not yet been described in the Golden Syrian hamster model of SARS-CoV-2 infection. The study aimed to evaluate microscopic liver lesions in Golden Syrian hamsters experimentally infected with SARS-CoV-2. In total, 38 conventional Golden Syrian hamsters, divided into infected group (n=24) and mock-infected group (n=14), were euthanized at 2-, 3-, 4-, 5-, 7-, 14-, and 15-days post infection with SARS-CoV-2. Liver fragments were evaluated by histopathology and immunohistochemical detection of SARS-CoV-2 Spike S2 antigens. The frequencies of portal vein endotheliitis, lobular activity, hepatocellular degeneration, and lobular vascular changes were higher among SARS-CoV-2-infected animals. Spike S2 antigen was not detected in liver. The main results indicate that SARS-CoV-2 infection exacerbated vascular and inflammatory lesions in the liver of hamsters with pre-existing hepatitis of unknown origin. A potential application of this animal model in studies of the pathogenesis and evolution of liver lesions associated with SARS-CoV-2 infection still needs further evaluation.


Subject(s)
COVID-19 , Disease Models, Animal , Liver , Mesocricetus , SARS-CoV-2 , Animals , COVID-19/pathology , Cricetinae , Liver/pathology , Liver/virology , Male
2.
J Transl Med ; 22(1): 698, 2024 Jul 29.
Article in English | MEDLINE | ID: mdl-39075394

ABSTRACT

BACKGROUND: Severe COVID-19 infection has been associated with the development of pulmonary fibrosis, a condition that significantly affects patient prognosis. Understanding the underlying cellular communication mechanisms contributing to this fibrotic process is crucial. OBJECTIVE: In this study, we aimed to investigate the role of the TNFSF12-TNFRSF12A pathway in mediating communication between alveolar macrophages and fibroblasts, and its implications for the development of pulmonary fibrosis in severe COVID-19 patients. METHODS: We conducted single-cell RNA sequencing (scRNA-seq) analysis using lung tissue samples from severe COVID-19 patients and healthy controls. The data was processed, analyzed, and cell types were annotated. We focused on the communication between alveolar macrophages and fibroblasts and identified key signaling pathways. In vitro experiments were performed to validate our findings, including the impact of TNFRSF12A silencing on fibrosis reversal. RESULTS: Our analysis revealed that in severe COVID-19 patients, alveolar macrophages communicate with fibroblasts primarily through the TNFSF12-TNFRSF12A pathway. This communication pathway promotes fibroblast proliferation and expression of fibrotic factors. Importantly, silencing TNFRSF12A effectively reversed the pro-proliferative and pro-fibrotic effects of alveolar macrophages. CONCLUSION: The TNFSF12-TNFRSF12A pathway plays a central role in alveolar macrophage-fibroblast communication and contributes to pulmonary fibrosis in severe COVID-19 patients. Silencing TNFRSF12A represents a potential therapeutic strategy for mitigating fibrosis in severe COVID-19 lung disease.


Subject(s)
COVID-19 , Fibroblasts , Macrophages, Alveolar , Pulmonary Fibrosis , Signal Transduction , TWEAK Receptor , Humans , COVID-19/complications , COVID-19/pathology , Macrophages, Alveolar/metabolism , Macrophages, Alveolar/pathology , Fibroblasts/metabolism , Fibroblasts/pathology , Pulmonary Fibrosis/pathology , Pulmonary Fibrosis/genetics , Pulmonary Fibrosis/complications , TWEAK Receptor/metabolism , TWEAK Receptor/genetics , Cytokine TWEAK/metabolism , Cell Communication , Male , SARS-CoV-2 , Female , Middle Aged , Cell Proliferation , Lung/pathology , Severity of Illness Index
3.
World J Gastroenterol ; 30(22): 2866-2880, 2024 Jun 14.
Article in English | MEDLINE | ID: mdl-38947288

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by the highly pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily impacts the respiratory tract and can lead to severe outcomes such as acute respiratory distress syndrome, multiple organ failure, and death. Despite extensive studies on the pathogenicity of SARS-CoV-2, its impact on the hepatobiliary system remains unclear. While liver injury is commonly indicated by reduced albumin and elevated bilirubin and transaminase levels, the exact source of this damage is not fully understood. Proposed mechanisms for injury include direct cytotoxicity, collateral damage from inflammation, drug-induced liver injury, and ischemia/hypoxia. However, evidence often relies on blood tests with liver enzyme abnormalities. In this comprehensive review, we focused solely on the different histopathological manifestations of liver injury in COVID-19 patients, drawing from liver biopsies, complete autopsies, and in vitro liver analyses. We present evidence of the direct impact of SARS-CoV-2 on the liver, substantiated by in vitro observations of viral entry mechanisms and the actual presence of viral particles in liver samples resulting in a variety of cellular changes, including mitochondrial swelling, endoplasmic reticulum dilatation, and hepatocyte apoptosis. Additionally, we describe the diverse liver pathology observed during COVID-19 infection, encompassing necrosis, steatosis, cholestasis, and lobular inflammation. We also discuss the emergence of long-term complications, notably COVID-19-related secondary sclerosing cholangitis. Recognizing the histopathological liver changes occurring during COVID-19 infection is pivotal for improving patient recovery and guiding decision-making.


Subject(s)
COVID-19 , Liver , SARS-CoV-2 , Humans , COVID-19/complications , COVID-19/pathology , COVID-19/virology , Liver/pathology , Liver/virology , SARS-CoV-2/pathogenicity , Liver Diseases/pathology , Liver Diseases/virology , Liver Diseases/etiology , Hepatocytes/pathology , Hepatocytes/virology
4.
Sci Transl Med ; 16(756): eadn0136, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-39018367

ABSTRACT

Postacute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (PASC) represent an urgent public health challenge and are estimated to affect more than 60 million individuals globally. Although a growing body of evidence suggests that dysregulated immune reactions may be linked with PASC symptoms, most investigations have primarily centered around blood-based studies, with few focusing on samples derived from affected tissues. Furthermore, clinical studies alone often provide correlative insights rather than causal mechanisms. Thus, it is essential to compare clinical samples with relevant animal models and conduct functional experiments to understand the etiology of PASC. In this study, we comprehensively compared bronchoalveolar lavage fluid single-cell RNA sequencing data derived from clinical PASC samples and a mouse model of PASC. This revealed a pro-fibrotic monocyte-derived macrophage response in respiratory PASC, as well as abnormal interactions between pulmonary macrophages and respiratory resident T cells, in both humans and mice. Interferon-γ (IFN-γ) emerged as a key node mediating the immune anomalies in respiratory PASC. Neutralizing IFN-γ after the resolution of acute SARS-CoV-2 infection reduced lung inflammation and tissue fibrosis in mice. Together, our study underscores the importance of performing comparative analysis to understand the cause of PASC and suggests that the IFN-γ signaling axis might represent a therapeutic target.


Subject(s)
Bronchoalveolar Lavage Fluid , COVID-19 , Interferon-gamma , SARS-CoV-2 , Single-Cell Analysis , COVID-19/immunology , COVID-19/pathology , COVID-19/virology , COVID-19/complications , Animals , Interferon-gamma/metabolism , Humans , Mice , Bronchoalveolar Lavage Fluid/virology , Disease Models, Animal , Lung/pathology , Lung/virology , Mice, Inbred C57BL , Macrophages, Alveolar/immunology , Male , Female , T-Lymphocytes/immunology
5.
Sci Rep ; 14(1): 16801, 2024 Jul 22.
Article in English | MEDLINE | ID: mdl-39039160

ABSTRACT

To examine corneal subbasal nerve changes in patients who received vaccination against SARS-CoV-2 virus and underwent COVID-19 infection compared to infected non-vaccinated patients and healthy controls. Twenty-nine eyes of 29 vaccinated patients (mean age: 36.66 ± 12.25 years) within six months after PCR or Ag test proven COVID-19 infection and twenty-eight eyes of 28 age-matched infected, non-vaccinated patients (mean age: 42.14 ± 14.17 years) were enrolled. Twenty-five age-matched healthy individuals (mean age: 47.52 ± 18.45 years) served as controls. In vivo confocal microscopy (Heidelberg Retina Tomograph II Rostock Cornea Module, Germany) was performed in each group. Corneal subbasal nerve plexus morphology and corneal dendritic cells (DC) were evaluated. Significantly higher corneal nerve fiber density (P < 0.001), nerve branch density (P < 0.001), nerve fiber length (P < 0.001), total branch density (P = 0.007), nerve fiber area (P = 0.001) and fractal dimension (P < 0.001) values were observed in vaccinated patients after COVID-19 infection compared to the non-vaccinated group. Significantly higher DC density was observed in the non-vaccinated group compared to the control group (P = 0.05). There was a statistically significant difference in the size of mature DCs (P < 0.0001) but the size of immature DCs did not differ significantly among the 3 groups (P = 0.132). Our results suggest that SARS-CoV-2 vaccination may have a protective effect against the complications of COVID-19 disease on the corneal subbasal nerve fibers.


Subject(s)
COVID-19 , Cornea , Nerve Fibers , SARS-CoV-2 , Vaccination , Humans , COVID-19/virology , COVID-19/pathology , COVID-19/prevention & control , Male , Female , Cornea/virology , Cornea/pathology , Cornea/innervation , Adult , Middle Aged , Nerve Fibers/pathology , Nerve Fibers/virology , SARS-CoV-2/isolation & purification , COVID-19 Vaccines/administration & dosage , Microscopy, Confocal , Dendritic Cells/immunology
6.
Neuropathol Appl Neurobiol ; 50(4): e12998, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39030945

ABSTRACT

AIMS: Diagnosis of idiopathic inflammatory myopathies (IIM) is based on morphological characteristics and the evaluation of disease-related proteins. However, although broadly applied, substantial bias is imposed by the respective methods, observers and individual staining approaches. We aimed to quantify the protein levels of major histocompatibility complex (MHC)-1, (MHC)-2 and intercellular adhesion molecule (ICAM)-1 using an automated morphometric method to mitigate bias. METHODS: Double immunofluorescence staining was performed on whole muscle sections to study differences in protein expression in myofibre and endomysial vessels. We analysed all IIM subtypes including dermatomyositis (DM), anti-synthetase syndrome (ASyS), inclusion body myositis (IBM), immune-mediated-necrotising myopathy (IMNM), dysferlinopathy (DYSF), SARS-CoV-2 infection and vaccination-associated myopathy. Biopsies with neurogenic atrophy (NA) and normal morphology served as controls. Bulk RNA-Sequencing (RNA-Seq) was performed on a subset of samples. RESULTS: Our study highlights the significance of MHC-1, MHC-2 and ICAM-1 in diagnosing IIM subtypes and reveals distinct immunological profiles. RNASeq confirmed the precision of our method and identified specific gene pathways in the disease subtypes. Notably, ASyS, DM and SARS-CoV-2-associated myopathy showed increased ICAM-1 expression in the endomysial capillaries, indicating ICAM-1-associated vascular activation in these conditions. In addition, ICAM-1 showed high discrimination between different subgroups with high sensitivity and specificity. CONCLUSIONS: Automated morphometric analysis provides precise quantitative data on immune-associated proteins that can be integrated into our pathophysiological understanding of IIM. Further, ICAM-1 holds diagnostic value for the detection of IIM pathology.


Subject(s)
Intercellular Adhesion Molecule-1 , Muscle, Skeletal , Myositis , Humans , Intercellular Adhesion Molecule-1/metabolism , Myositis/pathology , Myositis/diagnosis , Myositis/metabolism , Muscle, Skeletal/pathology , Muscle, Skeletal/metabolism , COVID-19/pathology , COVID-19/diagnosis , Male , Female , Diagnosis, Differential , Histocompatibility Antigens Class II/metabolism
7.
Front Cell Infect Microbiol ; 14: 1394721, 2024.
Article in English | MEDLINE | ID: mdl-38975331

ABSTRACT

Since 2019, Coronavirus Disease 2019(COVID-19) has affected millions of people worldwide. Except for acute respiratory distress syndrome, dysgeusis is also a common symptom of COVID-19 that burdens patients for weeks or permanently. However, the mechanisms underlying taste dysfunctions remain unclear. Here, we performed complete autopsies of five patients who died of COVID-19. Integrated tongue samples, including numerous taste buds, salivary glands, vessels, and nerves were collected to map the pathology, distribution, cell tropism, and receptor distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the tongue. Our results revealed that all patients had moderate lymphocyte infiltration around the salivary glands and in the lamina propria adjacent to the mucosa, and pyknosis in the epithelia of taste buds and salivary glands. This may be because the serous acini, salivary gland ducts, and taste buds are the primary sites of SARS-CoV-2 infection. Multicolor immunofluorescence showed that SARS-CoV-2 readily infects Keratin (KRT)7+ taste receptor cells in taste buds, secretory cells in serous acini, and inner epithelial cells in the ducts. The major receptors, angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), were both abundantly expressed in these cells. Viral antigens and receptor were both rarely detected in vessels and nerves. This indicates that SARS-CoV-2 infection triggers pathological injury in the tongue, and that dysgeusis may be directly related to viral infection and cellular damage.


Subject(s)
Angiotensin-Converting Enzyme 2 , Autopsy , COVID-19 , SARS-CoV-2 , Serine Endopeptidases , Tongue , Viral Tropism , Humans , COVID-19/pathology , COVID-19/virology , SARS-CoV-2/pathogenicity , Tongue/virology , Tongue/pathology , Male , Angiotensin-Converting Enzyme 2/metabolism , Female , Middle Aged , Serine Endopeptidases/metabolism , Salivary Glands/virology , Salivary Glands/pathology , Aged , Taste Buds/virology , Taste Buds/pathology , Receptors, Virus/metabolism
8.
Cell Mol Life Sci ; 81(1): 296, 2024 Jul 11.
Article in English | MEDLINE | ID: mdl-38992165

ABSTRACT

Next to its classical role in MHC II-mediated antigen presentation, CD74 was identified as a high-affinity receptor for macrophage migration inhibitory factor (MIF), a pleiotropic cytokine and major determinant of various acute and chronic inflammatory conditions, cardiovascular diseases and cancer. Recent evidence suggests that CD74 is expressed in T cells, but the functional relevance of this observation is poorly understood. Here, we characterized the regulation of CD74 expression and that of the MIF chemokine receptors during activation of human CD4+ T cells and studied links to MIF-induced T-cell migration, function, and COVID-19 disease stage. MIF receptor profiling of resting primary human CD4+ T cells via flow cytometry revealed high surface expression of CXCR4, while CD74, CXCR2 and ACKR3/CXCR7 were not measurably expressed. However, CD4+ T cells constitutively expressed CD74 intracellularly, which upon T-cell activation was significantly upregulated, post-translationally modified by chondroitin sulfate and could be detected on the cell surface, as determined by flow cytometry, Western blot, immunohistochemistry, and re-analysis of available RNA-sequencing and proteomic data sets. Applying 3D-matrix-based live cell-imaging and receptor pathway-specific inhibitors, we determined a causal involvement of CD74 and CXCR4 in MIF-induced CD4+ T-cell migration. Mechanistically, proximity ligation assay visualized CD74/CXCR4 heterocomplexes on activated CD4+ T cells, which were significantly diminished after MIF treatment, pointing towards a MIF-mediated internalization process. Lastly, in a cohort of 30 COVID-19 patients, CD74 surface expression was found to be significantly upregulated on CD4+ and CD8+ T cells in patients with severe compared to patients with only mild disease course. Together, our study characterizes the MIF receptor network in the course of T-cell activation and reveals CD74 as a novel functional MIF receptor and MHC II-independent activation marker of primary human CD4+ T cells.


Subject(s)
Antigens, Differentiation, B-Lymphocyte , CD4-Positive T-Lymphocytes , COVID-19 , Histocompatibility Antigens Class II , Intramolecular Oxidoreductases , Lymphocyte Activation , Macrophage Migration-Inhibitory Factors , SARS-CoV-2 , Humans , Antigens, Differentiation, B-Lymphocyte/metabolism , CD4-Positive T-Lymphocytes/metabolism , CD4-Positive T-Lymphocytes/immunology , Histocompatibility Antigens Class II/metabolism , Histocompatibility Antigens Class II/immunology , Macrophage Migration-Inhibitory Factors/metabolism , Macrophage Migration-Inhibitory Factors/genetics , Lymphocyte Activation/immunology , SARS-CoV-2/metabolism , SARS-CoV-2/immunology , COVID-19/immunology , COVID-19/metabolism , COVID-19/pathology , Intramolecular Oxidoreductases/metabolism , Intramolecular Oxidoreductases/genetics , Receptors, CXCR4/metabolism , Receptors, CXCR4/genetics , Cell Movement , Male , Female , Middle Aged , Receptors, Immunologic
9.
Cell Rep Med ; 5(7): 101642, 2024 Jul 16.
Article in English | MEDLINE | ID: mdl-38981485

ABSTRACT

In order to assess homeostatic mechanisms in the lung after COVID-19, changes in the protein signature of bronchoalveolar lavage from 45 patients with mild to moderate disease at three phases (acute, recovery, and convalescent) are evaluated over a year. During the acute phase, inflamed and uninflamed phenotypes are characterized by the expression of tissue repair and host defense response molecules. With recovery, inflammatory and fibrogenic mediators decline and clinical symptoms abate. However, at 9 months, quantified radiographic abnormalities resolve in the majority of patients, and yet compared to healthy persons, all showed ongoing activation of cellular repair processes and depression of the renin-kallikrein-kinin, coagulation, and complement systems. This dissociation of prolonged reparative processes from symptom and radiographic resolution suggests that occult ongoing disruption of the lung proteome is underrecognized and may be relevant to recovery from other serious viral pneumonias.


Subject(s)
COVID-19 , Lung , Proteome , SARS-CoV-2 , Humans , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Proteome/metabolism , Lung/metabolism , Lung/pathology , Lung/diagnostic imaging , Female , Male , Middle Aged , SARS-CoV-2/isolation & purification , Longitudinal Studies , Adult , Bronchoalveolar Lavage Fluid/chemistry , Aged
10.
Int J Mol Sci ; 25(13)2024 Jun 28.
Article in English | MEDLINE | ID: mdl-39000276

ABSTRACT

Neurologic manifestations are an immediate consequence of SARS-CoV-2 infection, the etiologic agent of COVID-19, which, however, may also trigger long-term neurological effects. Notably, COVID-19 patients with neurological symptoms show elevated levels of biomarkers associated with brain injury, including Tau proteins linked to Alzheimer's pathology. Studies in brain organoids revealed that SARS-CoV-2 alters the phosphorylation and distribution of Tau in infected neurons, but the mechanisms are currently unknown. We hypothesize that these pathological changes are due to the recruitment of Tau into stress granules (SGs) operated by the nucleocapsid protein (NCAP) of SARS-CoV-2. To test this hypothesis, we investigated whether NCAP interacts with Tau and localizes to SGs in hippocampal neurons in vitro and in vivo. Mechanistically, we tested whether SUMOylation, a posttranslational modification of NCAP and Tau, modulates their distribution in SGs and their pathological interaction. We found that NCAP and Tau colocalize and physically interact. We also found that NCAP induces hyperphosphorylation of Tau and causes cognitive impairment in mice infected with NCAP in their hippocampus. Finally, we found that SUMOylation modulates NCAP SG formation in vitro and cognitive performance in infected mice. Our data demonstrate that NCAP induces Tau pathological changes both in vitro and in vivo. Moreover, we demonstrate that SUMO2 ameliorates NCAP-induced Tau pathology, highlighting the importance of the SUMOylation pathway as a target of intervention against neurotoxic insults, such as Tau oligomers and viral infection.


Subject(s)
COVID-19 , Coronavirus Nucleocapsid Proteins , Hippocampus , Neurons , SARS-CoV-2 , Sumoylation , tau Proteins , tau Proteins/metabolism , Animals , Mice , Humans , Hippocampus/metabolism , Hippocampus/pathology , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , SARS-CoV-2/pathogenicity , SARS-CoV-2/metabolism , Phosphorylation , Coronavirus Nucleocapsid Proteins/metabolism , Neurons/metabolism , Neurons/pathology , Neurons/virology , Small Ubiquitin-Related Modifier Proteins/metabolism , Stress Granules/metabolism , Mice, Inbred C57BL , Phosphoproteins/metabolism , Male , Nucleocapsid Proteins/metabolism , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Cognitive Dysfunction/virology
11.
J Gen Virol ; 105(7)2024 Jul.
Article in English | MEDLINE | ID: mdl-38995681

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is associated with neurological sequelae including haemorrhage, thrombosis and ischaemic necrosis and encephalitis. However, the mechanism by which this occurs is unclear. Neurological disease associated with COVID-19 has been proposed to occur following direct infection of the central nervous system and/or indirectly by local or systemic immune activation. We evaluated the expression of angiotensin-converting enzyme-2 and transmembrane protease, serine 2 (TMPRSS2) in brain tissue from five healthy human donors and observed low-level expression of these proteins in cells morphologically consistent with astrocytes, neurons and choroidal ependymal cells within the frontal cortex and medulla oblongata. Primary human astrocytes, neurons, choroid plexus epithelial cells and pericytes supported productive SARS-CoV-2 infection with ancestral, Alpha, Delta and Omicron variants. Infected cells supported the full viral life cycle, releasing infectious virus particles. In contrast, primary brain microvascular endothelial cells and microglia were refractory to SARS-CoV-2 infection. These data support a model whereby SARS-CoV-2 can infect human brain cells, and the mechanism of viral entry warrants further investigation.


Subject(s)
Angiotensin-Converting Enzyme 2 , Astrocytes , COVID-19 , Choroid Plexus , Epithelial Cells , Neurons , Pericytes , SARS-CoV-2 , Serine Endopeptidases , Humans , Pericytes/virology , SARS-CoV-2/physiology , Astrocytes/virology , Choroid Plexus/virology , Angiotensin-Converting Enzyme 2/metabolism , Angiotensin-Converting Enzyme 2/genetics , Neurons/virology , COVID-19/virology , COVID-19/pathology , Epithelial Cells/virology , Serine Endopeptidases/metabolism , Serine Endopeptidases/genetics , Cells, Cultured , Brain/virology , Brain/pathology , Central Nervous System/virology
12.
J Med Virol ; 96(7): e29752, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38949191

ABSTRACT

Antiviral signaling, immune response and cell metabolism are dysregulated by SARS-CoV-2, the causative agent of COVID-19. Here, we show that SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10 induce a significant mitochondrial and metabolic reprogramming in A549 lung epithelial cells. While ORF9b, ORF9c and ORF10 induced largely overlapping transcriptomes, ORF3a induced a distinct transcriptome, including the downregulation of numerous genes with critical roles in mitochondrial function and morphology. On the other hand, all four ORFs altered mitochondrial dynamics and function, but only ORF3a and ORF9c induced a marked alteration in mitochondrial cristae structure. Genome-Scale Metabolic Models identified both metabolic flux reprogramming features both shared across all accessory proteins and specific for each accessory protein. Notably, a downregulated amino acid metabolism was observed in ORF9b, ORF9c and ORF10, while an upregulated lipid metabolism was distinctly induced by ORF3a. These findings reveal metabolic dependencies and vulnerabilities prompted by SARS-CoV-2 accessory proteins that may be exploited to identify new targets for intervention.


Subject(s)
COVID-19 , Mitochondria , SARS-CoV-2 , Viral Proteins , Humans , A549 Cells , COVID-19/metabolism , COVID-19/virology , COVID-19/pathology , Mitochondria/metabolism , Open Reading Frames , SARS-CoV-2/genetics , Transcriptome , Viral Proteins/genetics , Viral Proteins/metabolism , Viral Regulatory and Accessory Proteins/metabolism , Viral Regulatory and Accessory Proteins/genetics , Viroporin Proteins/metabolism
13.
Sci Transl Med ; 16(754): eadk3295, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38959327

ABSTRACT

The mechanisms of postacute medical conditions and unexplained symptoms after SARS-CoV-2 infection [Long Covid (LC)] are incompletely understood. There is growing evidence that viral persistence, immune dysregulation, and T cell dysfunction may play major roles. We performed whole-body positron emission tomography imaging in a well-characterized cohort of 24 participants at time points ranging from 27 to 910 days after acute SARS-CoV-2 infection using the radiopharmaceutical agent [18F]F-AraG, a selective tracer that allows for anatomical quantitation of activated T lymphocytes. Tracer uptake in the postacute COVID-19 group, which included those with and without continuing symptoms, was higher compared with prepandemic controls in many regions, including the brain stem, spinal cord, bone marrow, nasopharyngeal and hilar lymphoid tissue, cardiopulmonary tissues, and gut wall. T cell activation in the spinal cord and gut wall was associated with the presence of LC symptoms. In addition, tracer uptake in lung tissue was higher in those with persistent pulmonary symptoms specifically. Increased T cell activation in these tissues was also observed in many individuals without LC. Given the high [18F]F-AraG uptake detected in the gut, we obtained colorectal tissue for in situ hybridization of SARS-CoV-2 RNA and immunohistochemical studies in a subset of five participants with LC symptoms. We identified intracellular SARS-CoV-2 single-stranded spike protein-encoding RNA in rectosigmoid lamina propria tissue in all five participants and double-stranded spike protein-encoding RNA in three participants up to 676 days after initial COVID-19, suggesting that tissue viral persistence could be associated with long-term immunologic perturbations.


Subject(s)
COVID-19 , Lymphocyte Activation , Positron-Emission Tomography , RNA, Viral , SARS-CoV-2 , T-Lymphocytes , Humans , COVID-19/immunology , COVID-19/virology , COVID-19/pathology , T-Lymphocytes/immunology , Male , Middle Aged , Female , Adult , Aged , Lung/virology , Lung/pathology , Lung/diagnostic imaging , Time Factors
14.
Sci Immunol ; 9(97): eadn0178, 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-38996010

ABSTRACT

Virus-induced cell death is a key contributor to COVID-19 pathology. Cell death induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is well studied in myeloid cells but less in its primary host cell type, angiotensin-converting enzyme 2 (ACE2)-expressing human airway epithelia (HAE). SARS-CoV-2 induces apoptosis, necroptosis, and pyroptosis in HAE organotypic cultures. Single-cell and limiting-dilution analysis revealed that necroptosis is the primary cell death event in infected cells, whereas uninfected bystanders undergo apoptosis, and pyroptosis occurs later during infection. Mechanistically, necroptosis is induced by viral Z-RNA binding to Z-DNA-binding protein 1 (ZBP1) in HAE and lung tissues from patients with COVID-19. The Delta (B.1.617.2) variant, which causes more severe disease than Omicron (B1.1.529) in humans, is associated with orders of magnitude-greater Z-RNA/ZBP1 interactions, necroptosis, and disease severity in animal models. Thus, Delta induces robust ZBP1-mediated necroptosis and more disease severity.


Subject(s)
COVID-19 , Necroptosis , Pyroptosis , RNA-Binding Proteins , Respiratory Mucosa , SARS-CoV-2 , Humans , SARS-CoV-2/immunology , COVID-19/immunology , COVID-19/pathology , Necroptosis/immunology , Animals , Respiratory Mucosa/virology , Respiratory Mucosa/immunology , Respiratory Mucosa/pathology , RNA-Binding Proteins/metabolism , RNA-Binding Proteins/genetics , Mice , Cell Death/immunology , Angiotensin-Converting Enzyme 2/metabolism , Angiotensin-Converting Enzyme 2/genetics , Apoptosis/immunology
15.
Sci Immunol ; 9(97): eadp8170, 2024 Jul 12.
Article in English | MEDLINE | ID: mdl-38996011

ABSTRACT

Upon SARS-CoV-2 infection, infected cells undergo necroptosis, whereas delayed apoptosis and pyroptosis occur in uninfected, bystander cells, thus providing a plausible explanation for the extensive injury among myriad uninfected cells.


Subject(s)
COVID-19 , Necroptosis , Pyroptosis , SARS-CoV-2 , Humans , COVID-19/immunology , COVID-19/pathology , SARS-CoV-2/immunology , Pyroptosis/immunology , Necroptosis/immunology , Apoptosis/immunology , Cell Death/immunology , Animals
16.
Int J Mol Sci ; 25(13)2024 Jun 21.
Article in English | MEDLINE | ID: mdl-38999930

ABSTRACT

Although SARS-CoV-2 induces mucin hypersecretion in the respiratory tract, hyposalivation/xerostomia has been reported by COVID-19 patients. We evaluate the submandibular gland (SMGs) pathogenesis in SARS-CoV-2-infected K18-hACE2 mice, focusing on the impact of infection on the mucin production and structural integrity of acini, ductal system, myoepithelial cells (MECs) and telocytes. The spike protein, the nucleocapsid protein, hACE2, actin, EGF, TNF-α and IL-1ß were detected by immunofluorescence, and the Egfr and Muc5b expression was evaluated. In the infected animals, significant acinar hypertrophy was observed in contrast to ductal atrophy. Nucleocapsid proteins and/or viral particles were detected in the SMG cells, mainly in the nuclear membrane-derived vesicles, confirming the nuclear role in the viral formation. The acinar cells showed intense TNF-α and IL-1ß immunoexpression, and the EGF-EGFR signaling increased, together with Muc5b upregulation. This finding explains mucin hypersecretion and acinar hypertrophy, which compress the ducts. Dying MECs and actin reduction were also observed, indicating failure of contraction and acinar support, favoring acinar hypertrophy. Viral assembly was found in the dying telocytes, pointing to these intercommunicating cells as viral transmitters in SMGs. Therefore, EGF-EGFR-induced mucin hypersecretion was triggered by SARS-CoV-2 in acinar cells, likely mediated by cytokines. The damage to telocytes and MECs may have favored the acinar hypertrophy, leading to ductal obstruction, explaining xerostomia in COVID-19 patients. Thus, acinar cells, telocytes and MECs may be viral targets, which favor replication and cell-to-cell viral transmission in the SMG, corroborating the high viral load in saliva of infected individuals.


Subject(s)
COVID-19 , ErbB Receptors , SARS-CoV-2 , Submandibular Gland , Xerostomia , COVID-19/pathology , COVID-19/virology , COVID-19/metabolism , Animals , Submandibular Gland/virology , Submandibular Gland/pathology , Submandibular Gland/metabolism , SARS-CoV-2/physiology , Mice , Xerostomia/etiology , Xerostomia/pathology , Xerostomia/virology , Xerostomia/metabolism , ErbB Receptors/metabolism , Humans , Angiotensin-Converting Enzyme 2/metabolism , Mucin-5B/metabolism , Acinar Cells/pathology , Acinar Cells/metabolism , Acinar Cells/virology , Interleukin-1beta/metabolism , Tumor Necrosis Factor-alpha/metabolism , Disease Models, Animal
17.
J Med Virol ; 96(7): e29783, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38965890

ABSTRACT

Many COVID-19 patients suffer from gastrointestinal symptoms and impaired intestinal barrier function is thought to play a key role in Long COVID. Despite its importance, the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on intestinal epithelia is poorly understood. To address this, we established an intestinal barrier model integrating epithelial Caco-2 cells, mucus-secreting HT29 cells and Raji cells. This gut epithelial model allows efficient differentiation of Caco-2 cells into microfold-like cells, faithfully mimics intestinal barrier function, and is highly permissive to SARS-CoV-2 infection. Early strains of SARS-CoV-2 and the Delta variant replicated with high efficiency, severely disrupted barrier function, and depleted tight junction proteins, such as claudin-1, occludin, and ZO-1. In comparison, Omicron subvariants also depleted ZO-1 from tight junctions but had fewer damaging effects on mucosal integrity and barrier function. Remdesivir, the fusion inhibitor EK1 and the transmembrane serine protease 2 inhibitor Camostat inhibited SARS-CoV-2 replication and thus epithelial barrier damage, while the Cathepsin inhibitor E64d was ineffective. Our results support that SARS-CoV-2 disrupts intestinal barrier function but further suggest that circulating Omicron variants are less damaging than earlier viral strains.


Subject(s)
COVID-19 , Intestinal Mucosa , SARS-CoV-2 , Tight Junctions , Virus Replication , Humans , SARS-CoV-2/pathogenicity , Caco-2 Cells , COVID-19/virology , COVID-19/pathology , Intestinal Mucosa/virology , Intestinal Mucosa/pathology , Tight Junctions/virology , Alanine/analogs & derivatives , Zonula Occludens-1 Protein/metabolism , Zonula Occludens-1 Protein/genetics , Antiviral Agents/pharmacology , HT29 Cells , Occludin/metabolism , Occludin/genetics , Adenosine Monophosphate/analogs & derivatives
18.
Cell Commun Signal ; 22(1): 349, 2024 Jul 04.
Article in English | MEDLINE | ID: mdl-38965547

ABSTRACT

T lymphocytes play a primary role in the adaptive antiviral immunity. Both lymphocytosis and lymphopenia were found to be associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While lymphocytosis indicates an active anti-viral response, lymphopenia is a sign of poor prognosis. T-cells, in essence, rarely express ACE2 receptors, making the cause of cell depletion enigmatic. Moreover, emerging strains posed an immunological challenge, potentially alarming for the next pandemic. Herein, we review how possible indirect and direct key mechanisms could contribute to SARS-CoV-2-associated-lymphopenia. The fundamental mechanism is the inflammatory cytokine storm elicited by viral infection, which alters the host cell metabolism into a more acidic state. This "hyperlactic acidemia" together with the cytokine storm suppresses T-cell proliferation and triggers intrinsic/extrinsic apoptosis. SARS-CoV-2 infection also results in a shift from steady-state hematopoiesis to stress hematopoiesis. Even with low ACE2 expression, the presence of cholesterol-rich lipid rafts on activated T-cells may enhance viral entry and syncytia formation. Finally, direct viral infection of lymphocytes may indicate the participation of other receptors or auxiliary proteins on T-cells, that can work alone or in concert with other mechanisms. Therefore, we address the role of CD147-a novel route-for SARS-CoV-2 and its new variants. CD147 is not only expressed on T-cells, but it also interacts with other co-partners to orchestrate various biological processes. Given these features, CD147 is an appealing candidate for viral pathogenicity. Understanding the molecular and cellular mechanisms behind SARS-CoV-2-associated-lymphopenia will aid in the discovery of potential therapeutic targets to improve the resilience of our immune system against this rapidly evolving virus.


Subject(s)
Basigin , COVID-19 , Lymphopenia , SARS-CoV-2 , Humans , Lymphopenia/immunology , Lymphopenia/virology , COVID-19/immunology , COVID-19/virology , COVID-19/pathology , SARS-CoV-2/metabolism , Basigin/metabolism , Angiotensin-Converting Enzyme 2/metabolism , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , T-Lymphocytes/virology , Cytokine Release Syndrome/immunology , Animals
19.
Sci Transl Med ; 16(754): eadi6887, 2024 Jul 03.
Article in English | MEDLINE | ID: mdl-38959328

ABSTRACT

Virulent infectious agents such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and methicillin-resistant Staphylococcus aureus (MRSA) induce tissue damage that recruits neutrophils, monocyte, and macrophages, leading to T cell exhaustion, fibrosis, vascular leak, epithelial cell depletion, and fatal organ damage. Neutrophils, monocytes, and macrophages recruited to pathogen-infected lungs, including SARS-CoV-2-infected lungs, express phosphatidylinositol 3-kinase gamma (PI3Kγ), a signaling protein that coordinates both granulocyte and monocyte trafficking to diseased tissues and immune-suppressive, profibrotic transcription in myeloid cells. PI3Kγ deletion and inhibition with the clinical PI3Kγ inhibitor eganelisib promoted survival in models of infectious diseases, including SARS-CoV-2 and MRSA, by suppressing inflammation, vascular leak, organ damage, and cytokine storm. These results demonstrate essential roles for PI3Kγ in inflammatory lung disease and support the potential use of PI3Kγ inhibitors to suppress inflammation in severe infectious diseases.


Subject(s)
COVID-19 , Class Ib Phosphatidylinositol 3-Kinase , Inflammation , SARS-CoV-2 , Animals , Humans , Mice , Capillary Permeability/drug effects , Class Ib Phosphatidylinositol 3-Kinase/metabolism , COVID-19/pathology , COVID-19 Drug Treatment , Cytokine Release Syndrome/drug therapy , Inflammation/pathology , Lung/pathology , Methicillin-Resistant Staphylococcus aureus/drug effects , Mice, Inbred C57BL , Phosphoinositide-3 Kinase Inhibitors/pharmacology , Phosphoinositide-3 Kinase Inhibitors/therapeutic use , SARS-CoV-2/physiology , Staphylococcal Infections/drug therapy , Staphylococcal Infections/pathology
20.
Arkh Patol ; 86(4): 58-63, 2024.
Article in Russian | MEDLINE | ID: mdl-39073544

ABSTRACT

A literature review reflects data on the mechanisms of pulmonary fibrosis after a novel coronavirus infection associated with the SARS-COV2 virus. Factors contributing to post-COVID lung remodeling are considered. According to the literature, in the mechanism of pulmonary fibrosis, during the course of the disease and during the recovery period, both direct viral damage and death of alveolocytes and endothelium, the development of a systemic inflammatory reaction due to inadequate secretion of cytokines, especially type 2, which are activators of the proliferation of fibroblasts and myofibroblasts, are important. The influence of angiogenesis disorders and vascular dysfunction on pneumofibrosis was noted. Attention is also paid to the relationship between the development of pulmonary fibrosis and abnormal activation of the renin-angiotensin-aldosterone system. In combination with the action of many factors, especially germinal ones, an imbalance between profibrogenic and antifibrogenic action develops and fibrosis occurs.


Subject(s)
COVID-19 , Pulmonary Fibrosis , SARS-CoV-2 , Humans , Pulmonary Fibrosis/pathology , Pulmonary Fibrosis/etiology , Pulmonary Fibrosis/metabolism , COVID-19/complications , COVID-19/pathology , Renin-Angiotensin System , Cytokines/metabolism , Fibroblasts/pathology , Fibroblasts/metabolism , Myofibroblasts/pathology , Myofibroblasts/metabolism
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