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1.
Stem Cell Reports ; 17(5): 1089-1104, 2022 05 10.
Article in English | MEDLINE | ID: covidwho-1799706

ABSTRACT

Humanized mouse models and mouse-adapted SARS-CoV-2 virus are increasingly used to study COVID-19 pathogenesis, so it is important to learn where the SARS-CoV-2 receptor ACE2 is expressed. Here we mapped ACE2 expression during mouse postnatal development and in adulthood. Pericytes in the CNS, heart, and pancreas express ACE2 strongly, as do perineurial and adrenal fibroblasts, whereas endothelial cells do not at any location analyzed. In a number of other organs, pericytes do not express ACE2, including in the lung where ACE2 instead is expressed in bronchial epithelium and alveolar type II cells. The onset of ACE2 expression is organ specific: in bronchial epithelium already at birth, in brain pericytes before, and in heart pericytes after postnatal day 10.5. Establishing the vascular localization of ACE2 expression is central to correctly interpret data from modeling COVID-19 in the mouse and may shed light on the cause of vascular COVID-19 complications.


Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Pericytes , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/complications , Cardiovascular Diseases/virology , Endothelial Cells , Mice , Pericytes/metabolism , SARS-CoV-2
2.
Neurobiol Dis ; 161: 105561, 2021 12.
Article in English | MEDLINE | ID: covidwho-1510138

ABSTRACT

Coronavirus disease 19 (COVID-19) is a respiratory illness caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). COVID-19 pathogenesis causes vascular-mediated neurological disorders via elusive mechanisms. SARS-CoV-2 infects host cells via the binding of viral Spike (S) protein to transmembrane receptor, angiotensin-converting enzyme 2 (ACE2). Although brain pericytes were recently shown to abundantly express ACE2 at the neurovascular interface, their response to SARS-CoV-2 S protein is still to be elucidated. Using cell-based assays, we found that ACE2 expression in human brain vascular pericytes was increased upon S protein exposure. Pericytes exposed to S protein underwent profound phenotypic changes associated with an elongated and contracted morphology accompanied with an enhanced expression of contractile and myofibrogenic proteins, such as α-smooth muscle actin (α-SMA), fibronectin, collagen I, and neurogenic locus notch homolog protein-3 (NOTCH3). On the functional level, S protein exposure promoted the acquisition of calcium (Ca2+) signature of contractile ensheathing pericytes characterized by highly regular oscillatory Ca2+ fluctuations. Furthermore, S protein induced lipid peroxidation, oxidative and nitrosative stress in pericytes as well as triggered an immune reaction translated by activation of nuclear factor-kappa-B (NF-κB) signaling pathway, which was potentiated by hypoxia, a condition associated with vascular comorbidities that exacerbate COVID-19 pathogenesis. S protein exposure combined to hypoxia enhanced the production of pro-inflammatory cytokines involved in immune cell activation and trafficking, namely macrophage migration inhibitory factor (MIF). Using transgenic mice expressing the human ACE2 that recognizes S protein, we observed that the intranasal infection with SARS-CoV-2 rapidly induced hypoxic/ischemic-like pericyte reactivity in the brain of transgenic mice, accompanied with an increased vascular expression of ACE2. Moreover, we found that SARS-CoV-2 S protein accumulated in the intranasal cavity reached the brain of mice in which the nasal mucosa is deregulated. Collectively, these findings suggest that SARS-CoV-2 S protein impairs the vascular and immune regulatory functions of brain pericytes, which may account for vascular-mediated brain damage. Our study provides a better understanding for the mechanisms underlying cerebrovascular disorders in COVID-19, paving the way to develop new therapeutic interventions.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Brain/metabolism , COVID-19/metabolism , Hypoxia-Ischemia, Brain/metabolism , Hypoxia/metabolism , Inflammation/metabolism , Pericytes/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Actins/metabolism , Angiotensin-Converting Enzyme 2/drug effects , Angiotensin-Converting Enzyme 2/genetics , Animals , Brain/blood supply , COVID-19/physiopathology , Calcium Signaling , Collagen Type I/metabolism , Fibronectins/metabolism , Humans , Hypoxia-Ischemia, Brain/physiopathology , Lipid Peroxidation/drug effects , Lipid Peroxidation/genetics , Macrophage Migration-Inhibitory Factors/drug effects , Macrophage Migration-Inhibitory Factors/metabolism , Mice , Mice, Transgenic , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/cytology , Myocytes, Smooth Muscle/metabolism , Myofibroblasts , NF-kappa B/drug effects , NF-kappa B/metabolism , Nasal Mucosa , Nitrosative Stress , Oxidative Stress , Pericytes/cytology , Pericytes/drug effects , Phenotype , Receptor, Notch3/metabolism , Receptors, Coronavirus/drug effects , Receptors, Coronavirus/genetics , Receptors, Coronavirus/metabolism , Spike Glycoprotein, Coronavirus/pharmacology
3.
Int J Mol Sci ; 22(21)2021 Oct 27.
Article in English | MEDLINE | ID: covidwho-1488609

ABSTRACT

A wide range of neurological manifestations have been associated with the development of COVID-19 following SARS-CoV-2 infection. However, the etiology of the neurological symptomatology is still largely unexplored. Here, we used state-of-the-art multiplexed immunostaining of human brains (n = 6 COVID-19, median age = 69.5 years; n = 7 control, median age = 68 years) and demonstrated that expression of the SARS-CoV-2 receptor ACE2 is restricted to a subset of neurovascular pericytes. Strikingly, neurological symptoms were exclusive to, and ubiquitous in, patients that exhibited moderate to high ACE2 expression in perivascular cells. Viral dsRNA was identified in the vascular wall and paralleled by perivascular inflammation, as signified by T cell and macrophage infiltration. Furthermore, fibrinogen leakage indicated compromised integrity of the blood-brain barrier. Notably, cerebrospinal fluid from additional 16 individuals (n = 8 COVID-19, median age = 67 years; n = 8 control, median age = 69.5 years) exhibited significantly lower levels of the pericyte marker PDGFRß in SARS-CoV-2-infected cases, indicative of disrupted pericyte homeostasis. We conclude that pericyte infection by SARS-CoV-2 underlies virus entry into the privileged central nervous system space, as well as neurological symptomatology due to perivascular inflammation and a locally compromised blood-brain barrier.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Brain/virology , COVID-19/physiopathology , Encephalitis, Viral/virology , Pericytes/virology , Angiotensin-Converting Enzyme 2/genetics , Animals , Blood-Brain Barrier , Brain/pathology , COVID-19/etiology , Case-Control Studies , Encephalitis, Viral/pathology , Fibrinogen/metabolism , Humans , Immunohistochemistry/methods , Mice , Pericytes/metabolism , Pericytes/pathology , Receptor, Platelet-Derived Growth Factor beta/cerebrospinal fluid
4.
Cells ; 10(9)2021 09 04.
Article in English | MEDLINE | ID: covidwho-1403545

ABSTRACT

Stroke is the third leading cause of mortality in women and it kills twice as many women as breast cancer. A key role in the pathophysiology of stroke plays the disruption of the blood-brain barrier (BBB) within the neurovascular unit. While estrogen induces vascular protective actions, its influence on stroke remains unclear. Moreover, experiments assessing its impact on endothelial cells to induce barrier integrity are non-conclusive. Since pericytes play an active role in regulating BBB integrity and function, we hypothesize that estradiol may influence BBB by regulating their activity. In this study using human brain vascular pericytes (HBVPs) we investigated the impact of estradiol on key pericyte functions known to influence BBB integrity. HBVPs expressed estrogen receptors (ER-α, ER-ß and GPER) and treatment with estradiol (10 nM) inhibited basal cell migration but not proliferation. Since pericyte migration is a hallmark for BBB disruption following injury, infection and inflammation, we investigated the effects of estradiol on TNFα-induced PC migration. Importantly, estradiol prevented TNFα-induced pericyte migration and this effect was mimicked by PPT (ER-α agonist) and DPN (ER-ß agonist), but not by G1 (GPR30 agonist). The modulatory effects of estradiol were abrogated by MPP and PHTPP, selective ER-α and ER-ß antagonists, respectively, confirming the role of ER-α and ER-ß in mediating the anti-migratory actions of estrogen. To delineate the intracellular mechanisms mediating the inhibitory actions of estradiol on PC migration, we investigated the role of AKT and MAPK activation. While estradiol consistently reduced the TNFα-induced MAPK and Akt phosphorylation, only the inhibition of MAPK, but not Akt, significantly abrogated the migratory actions of TNFα. In transendothelial electrical resistance measurements, estradiol induced barrier function (TEER) in human brain microvascular endothelial cells co-cultured with pericytes, but not in HBMECs cultured alone. Importantly, transcriptomics analysis of genes modulated by estradiol in pericytes showed downregulation of genes known to increase cell migration and upregulation of genes known to inhibit cell migration. Taken together, our findings provide the first evidence that estradiol modulates pericyte activity and thereby improves endothelial integrity.


Subject(s)
Brain/blood supply , Cell Movement/drug effects , Estradiol/pharmacology , Gene Expression Profiling , Pericytes/cytology , Cell Movement/genetics , Cell Proliferation/drug effects , Cells, Cultured , Endothelial Cells/drug effects , Endothelial Cells/metabolism , Gene Expression Regulation/drug effects , Humans , Mitogen-Activated Protein Kinases/metabolism , Pericytes/drug effects , Pericytes/metabolism , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Receptors, Estrogen/metabolism , Tumor Necrosis Factor-alpha/metabolism
5.
Nature ; 588(7838): 466-472, 2020 12.
Article in English | MEDLINE | ID: covidwho-1075229

ABSTRACT

Cardiovascular disease is the leading cause of death worldwide. Advanced insights into disease mechanisms and therapeutic strategies require a deeper understanding of the molecular processes involved in the healthy heart. Knowledge of the full repertoire of cardiac cells and their gene expression profiles is a fundamental first step in this endeavour. Here, using state-of-the-art analyses of large-scale single-cell and single-nucleus transcriptomes, we characterize six anatomical adult heart regions. Our results highlight the cellular heterogeneity of cardiomyocytes, pericytes and fibroblasts, and reveal distinct atrial and ventricular subsets of cells with diverse developmental origins and specialized properties. We define the complexity of the cardiac vasculature and its changes along the arterio-venous axis. In the immune compartment, we identify cardiac-resident macrophages with inflammatory and protective transcriptional signatures. Furthermore, analyses of cell-to-cell interactions highlight different networks of macrophages, fibroblasts and cardiomyocytes between atria and ventricles that are distinct from those of skeletal muscle. Our human cardiac cell atlas improves our understanding of the human heart and provides a valuable reference for future studies.


Subject(s)
Myocardium/cytology , Single-Cell Analysis , Transcriptome , Adipocytes/classification , Adipocytes/metabolism , Adult , Angiotensin-Converting Enzyme 2/analysis , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Epithelial Cells/classification , Epithelial Cells/metabolism , Epithelium , Female , Fibroblasts/classification , Fibroblasts/metabolism , Gene Expression Profiling , Genome-Wide Association Study , Heart Atria/anatomy & histology , Heart Atria/cytology , Heart Atria/innervation , Heart Ventricles/anatomy & histology , Heart Ventricles/cytology , Heart Ventricles/innervation , Homeostasis/immunology , Humans , Macrophages/immunology , Macrophages/metabolism , Male , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Myocytes, Cardiac/classification , Myocytes, Cardiac/metabolism , Neurons/classification , Neurons/metabolism , Pericytes/classification , Pericytes/metabolism , Receptors, Coronavirus/analysis , Receptors, Coronavirus/genetics , Receptors, Coronavirus/metabolism , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Stromal Cells/classification , Stromal Cells/metabolism
6.
Curr Neurovasc Res ; 17(5): 784-792, 2020.
Article in English | MEDLINE | ID: covidwho-999945

ABSTRACT

A pericyte-centered theory suggesting that embolisms occurring within the microvasculature of a neurovascular unit that can result in either parenchymal hemorrhage or intravascular congestion is presented here. Dysfunctional microvascular pericytes are characterized by their location in the neurovascular unit, either on the arteriole or venule side. Pathophysiological and pathological changes caused by coronavirus disease 2019 (COVID-19) include pulmonary hypertension, edema, focal hemorrhage, microvascular congestion, and thrombosis. In this paper, the application of the pericytes-centered hypothesis to COVID-19 has been presented by proposing the concept of a pulmonary neurovascular unit (pNVU). The application of this concept implies that human lungs contain approximately 300 million pNVUs. This concept of existing local regulation of microvascular blood flow is supported by the observation of pathophysiology in pulmonary embolism and in acute high-altitude illness. The autonomic control seen in these three disease states matches blood flow with oxygen supply in each pNVU to maintain physiological blood oxygen saturation level. This paper illustrates how the malfunction of microvascular pericytes may cause focal hemorrhage, edema or microvascular congestion and thrombosis. A bypass existing in each pNVU would autonomically deviate blood flow from a COVID-19-affected pNVU to other healthy pNVUs. This action would prevent systemically applied medicines from reaching the therapeutic threshold in COVID-19-affected pNVUs. While testing this hypothesis with experimental evidence is urgently needed, supporting therapy aimed at improving microcirculation or rebuilding the physiological function of microvascular pericytes is recommended as a potentially effective treatment of COVID 19.


Subject(s)
Blood-Brain Barrier/metabolism , Brain/metabolism , COVID-19/metabolism , Neurovascular Coupling/physiology , Pericytes/metabolism , Animals , Blood-Brain Barrier/pathology , Brain/pathology , COVID-19/pathology , Humans , Microcirculation/physiology , Microvessels/metabolism , Microvessels/pathology , Pericytes/pathology
7.
FASEB J ; 34(9): 11347-11354, 2020 09.
Article in English | MEDLINE | ID: covidwho-691159

ABSTRACT

A relationship between COVID-19 infection and an increasing incidence of atrial fibrillation has been observed. However, the underlying pathophysiology as a precipitant to AF has not been reviewed. This paper will consider the possible pathological and immunological AF mechanisms as a result, of COVID-19 infection. We discuss the role myocardial microvascular pericytes expressing the ACE-2 receptor and their potential for an organ-specific cardiac involvement with COVID-19. Dysfunctional microvascular support by pericytes or endothelial cells may increase the propensity for AF via increased myocardial inflammation, fibrosis, increased tissue edema, and interstitial hydrostatic pressure. All of these factors can lead to electrical perturbances at the tissue and cellular level. We also consider the contribution of Angiotensin, pulmonary hypertension, and regulatory T cells as additional contributors to AF during COVID-19 infection. Finally, reference is given to two common drugs, corticosteroids and metformin, in COVID-19 and how they might influence AF incidence.


Subject(s)
Atrial Fibrillation/etiology , Coronavirus Infections/complications , Pneumonia, Viral/complications , Angiotensin-Converting Enzyme 2 , Atrial Fibrillation/metabolism , COVID-19 , Coronavirus Infections/metabolism , Endothelial Cells/metabolism , Humans , Pandemics , Peptidyl-Dipeptidase A/metabolism , Pericytes/metabolism , Pneumonia, Viral/metabolism , Renin-Angiotensin System
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