SARS-CoV-2 crosses the blood-brain barrier accompanied with basement membrane disruption without tight junctions alteration
Signal transduction and targeted therapy
Zhang, L;Zhou, L;Bao, L;Liu, J;Zhu, H;Lv, Q;Liu, R;Chen, W;Tong, W;Wei, Q;Xu, Y;Deng, W;Gao, H;Xue, J;Song, Z;Yu, P;Han, Y;Zhang, Y;Sun, X;Yu, X;Qin, C;
PMID: 34489403 | DOI: 10.1038/s41392-021-00719-9
SARS-CoV-2 has been reported to show a capacity for invading the brains of humans and model animals. However, it remains unclear whether and how SARS-CoV-2 crosses the blood-brain barrier (BBB). Herein, SARS-CoV-2 RNA was occasionally detected in the vascular wall and perivascular space, as well as in brain microvascular endothelial cells (BMECs) in the infected K18-hACE2 transgenic mice. Moreover, the permeability of the infected vessel was increased. Furthermore, disintegrity of BBB was discovered in the infected hamsters by administration of Evans blue. Interestingly, the expression of claudin5, ZO-1, occludin and the ultrastructure of tight junctions (TJs) showed unchanged, whereas, the basement membrane was disrupted in the infected animals. Using an in vitro BBB model that comprises primary BMECs with astrocytes, SARS-CoV-2 was found to infect and cross through the BMECs. Consistent with in vivo experiments, the expression of MMP9 was increased and collagen IV was decreased while the markers for TJs were not altered in the SARS-CoV-2-infected BMECs. Besides, inflammatory responses including vasculitis, glial activation, and upregulated inflammatory factors occurred after SARS-CoV-2 infection. Overall, our results provide evidence supporting that SARS-CoV-2 can cross the BBB in a transcellular pathway accompanied with basement membrane disrupted without obvious alteration of TJs.
Role of ACE2 in pregnancy and potential implications for COVID-19 susceptibility
Clinical science (London, England : 1979)
Azinheira Nobrega Cruz, N;Stoll, D;Casarini, DE;Bertagnolli, M;
PMID: 34338772 | DOI: 10.1042/CS20210284
In times of coronavirus disease 2019 (COVID-19), the impact of severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 infection on pregnancy is still unclear. The presence of angiotensin-converting enzyme (ACE) 2 (ACE2), the main receptor for SARS-CoV-2, in human placentas indicates that this organ can be vulnerable for viral infection during pregnancy. However, for this to happen, additional molecular processes are critical to allow viral entry in cells, its replication and disease manifestation, particularly in the placenta and/or feto-maternal circulation. Beyond the risk of vertical transmission, COVID-19 is also proposed to deplete ACE2 protein and its biological actions in the placenta. It is postulated that such effects may impair essential processes during placentation and maternal hemodynamic adaptations in COVID-19 pregnancy, features also observed in several disorders of pregnancy. This review gathers information indicating risks and protective features related to ACE2 changes in COVID-19 pregnancies. First, we describe the mechanisms of SARS-CoV-2 infection having ACE2 as a main entry door and current evidence of viral infection in the placenta. Further, we discuss the central role of ACE2 in physiological systems such as the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS), both active during placentation and hemodynamic adaptations of pregnancy. Significant knowledge gaps are also identified and should be urgently filled to better understand the fate of ACE2 in COVID-19 pregnancies and the potential associated risks. Emerging knowledge will be able to improve the early stratification of high-risk pregnancies with COVID-19 exposure as well as to guide better management and follow-up of these mothers and their children.
Single-Cell RNA-seq Reveals Angiotensin-Converting Enzyme 2 and Transmembrane Serine Protease 2 Expression in TROP2+ Liver Progenitor Cells: Implications in Coronavirus Disease 2019-Associated Liver Dysfunction
Seow, JJW;Pai, R;Mishra, A;Shepherdson, E;Lim, TKH;Goh, BKP;Chan, JKY;Chow, PKH;Ginhoux, F;DasGupta, R;Sharma, A;
PMID: 33968947 | DOI: 10.3389/fmed.2021.603374
The recent coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2. COVID-19 was first reported in China (December 2019) and is now prevalent across the globe. Entry of severe acute respiratory syndrome coronavirus 2 into mammalian cells requires the binding of viral Spike (S) proteins to the angiotensin-converting enzyme 2 receptor. Once entered, the S protein is primed by a specialized serine protease, transmembrane serine protease 2 in the host cell. Importantly, besides the respiratory symptoms that are consistent with other common respiratory virus infections when patients become viremic, a significant number of COVID-19 patients also develop liver comorbidities. We explored whether a specific target cell-type in the mammalian liver could be implicated in disease pathophysiology other than the general deleterious response to cytokine storms. Here, we used single-cell RNA-seq to survey the human liver and identified potentially implicated liver cell-type for viral ingress. We analyzed ~300,000 single cells across five different (i.e., human fetal, healthy, cirrhotic, tumor, and adjacent normal) liver tissue types. This study reports on the co-expression of angiotensin-converting enzyme 2 and transmembrane serine protease 2 in a TROP2+ liver progenitor population. Importantly, we detected enrichment of this cell population in the cirrhotic liver when compared with tumor tissue. These results indicated that in COVID-19-associated liver dysfunction and cell death, a viral infection of TROP2+ progenitors in the liver might significantly impair liver regeneration in patients with liver cirrhosis.
EXPRESS: Mechanisms of SARS-CoV-2 Induced Lung Vascular Disease: Potential Role of Complement
Stenmark, K;Frid, M;gerasimovskaya, e;zhang, h;McCarthy, M;Thurman, J;Morrison, T;
| DOI: 10.1177/20458940211015799
: The outbreak of COVID-19 disease, caused by SARS-CoV-2 beta-coronovirus, urges a focused search for the underlying mechanisms and treatment options. The lung is the major target organ of COVID-19, wherein the primary cause of mortality is hypoxic respiratory failure, resulting from acute respiratory disease syndrome (ARDS), with severe hypoxemia, often requiring assisted ventilation. While similar in some ways to ARDS secondary to other causes, lungs of some patients dying with COVID-19 exhibit distinct features of vascular involvement, including severe endothelial injury and cell death via apoptosis and/or pyroptosis, widespread capillary inflammation and thrombosis. Furthermore, the pulmonary pathology of COVID-19 is characterized by focal inflammatory cell infiltration, impeding alveolar gas exchange resulting in areas of local tissue hypoxia, consistent with potential amplification of COVID-19 pathogenicity by hypoxia. Vascular endothelial cells play essential roles in both innate and adaptive immune responses, and are considered to be âconditional innate immune cellsâ centrally participating in various inflammatory, immune pathologies. Activated endothelial cells produce cytokines/chemokines, dynamically recruit and activate inflammatory cells and platelets, and centrally participate in pro-thrombotic processes (thrombotic microangiopathies). Initial reports presented pathological findings of localized direct infection of vascular endothelial cells with SARS-CoV-2, yet emerging evidence does not support direct infection of endothelial or other vascular wall cell and thus widespread endothelial cell dysfunction and inflammation may be better explained as secondary responses to epithelial cell infection and inflammation. Endothelial cells are also actively engaged in a cross-talk with the complement system, the essential arm of innate immunity. Recent reports present evidence for complement deposition in SARS-CoV-2-damaged lung microcirculation, further strengthening the idea that, in severe cases of COVID-19, complement activation is an essential player, generating destructive hemorrhagic, capillariitis-like tissue damage, clotting, and hyper-inflammation. Thus, complement-targeted therapies are actively in development. This review is intended to explore in detail these ideas.
Binding of SARS-CoV-2 to the avb6 Integrins May Promote Severe COVID in Patients with IPF
TP105. TP105 BASIC MECHANISMS OF LUNG INFECTIONS: FROM SARS-COV-2 TO INFLUENZA
Joseph, C;Peacock, T;Calver, J;John, A;Organ, L;Fainberg, H;Porte, J;Mukhopadhyay, S;Barton, L;Stroberg, E;Duval, E;Copin, M;Poissy, J;Steinestel, K;Tatler, A;Barclay, W;Jenkins, G;
| DOI: 10.1164/ajrccm-conference.2021.203.1_MeetingAbstracts.A4170
RATIONALE: Patients with idiopathic pulmonary fibrosis (IPF) have worse outcomes following COVID-19. SARSCoV-2 (2019-nCoV) spike protein (S1) harbors an RGD motif in its receptor-binding domain (RBD). Although SARS-CoV-2 is to exploit human Angiotensin Converting Enzyme-2 (ACE2) receptors for cell entry. Single Cell RNA-seq showed that normal lung expresses low levels of ACE2 with very low expression (1.5%) in Alveolar type 2 epithelial cells. It is possible that SARS-CoV-2 needs a cellular co-receptor, which could include integrins, to promote alveolar cell internalization and pneumonitis.METHODS: Solid-phase binding assays were used to investigate S1 binding to ACE2 or αv containing integrins. Pseudovirus entry assays were used to measure the internalization of SARS-CoV-2 into Human embryonic kidney 293T cells expressing different combinations of potential receptors. RNAscope was used to visualize the co-localization of SARS-CoV-2, ACE2, and integrin mRNAs. Immunohistochemistry was used to evaluate the expression of αvβ6 integrins and ACE2 in lung tissue.RESULTS: Binding assays demonstrated that the RGD containing αvβ3 and αvβ6 integrins bound robustly to the SARS-CoV-2 S1 subunit of Spike protein and overexpression of the αvβ6 integrin modestly augments ACE2 mediated SARS-CoV-2 pseudoviral entry into epithelial cells. In COVID-19 damaged lung ACE2 levels are low but the αvβ6 integrin levels are increased in alveolar epithelium whereas both ACE2 and αvβ6 integrin are increased in lung sections from idiopathic pulmonary fibrosis compared with normal lung samples. CONCLUSION: The SARS-CoV-2 S1 subunit can bind αvβ6 integrins augmenting ACE2-dependent internalization of pseudovirus. In IPF patients, ACE2 levels and αvβ6 integrin levels are increased. Increased binding of the SARS-CoV-2 to ACE2 and the αvβ6 integrin within fibrotic lung may explain the increased risk of severe COVID in patients with IPF.
The \"Oral\" History of COVID-19: Primary Infection, Salivary Transmission, and Post-Acute Implications
Journal of periodontology
Marchesan, JT;Warner, BM;Byrd, KM;
PMID: 34390597 | DOI: 10.1002/JPER.21-0277
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, has led to more than 3.25 million recorded deaths worldwide as of May 2021. COVID-19 is known to be clinically heterogeneous, and whether the reported oral signs and symptoms in COVID-19 are related to the direct infection of oral tissues has remained unknown. Here, we review and summarize the evidence for the primary infection of the glands, oral mucosae, and saliva by SARS-CoV-2. Not only were the entry factors for SARS-CoV-2 found in all oral tissues, but these were also sites of SARS-CoV-2 infection and replication. Furthermore, saliva from asymptomatic individuals contained free virus and SARS-CoV-2-infected oral epithelial cells, both of which were found to transmit the virus. Collectively, these studies support an active role of the oral cavity in the spread and transmission of SARS-CoV-2 infection. In addition to maintaining the appropriate use of personal protective equipment and regimens to limit microbial spread via aerosol or droplet generation, the dental community will also be involved in co-managing COVID-19 'long haulers'-now termed Post-Acute COVID-19 Syndrome. Consequently, we propose that, as SARS-CoV-2 continues to spread and as new clinical challenges related to COVID-19 are documented, oral symptoms should be included in diagnostic and prognostic classifications as well as plans for multidisciplinary care. This article is protected by
Jansen, J;Reimer, K;Nagai, J;Varghese, F;Overheul, G;de Beer, M;Roverts, R;Daviran, D;Fermin, L;Willemsen, B;Beukenboom, M;Djudjaj, S;von Stillfried, S;van Eijk, L;Mastik, M;Bulthuis, M;Dunnen, W;van Goor, H;Hillebrands, J;Triana, S;Alexandrov, T;Timm, M;Tideman van den Berge, B;van den Broek, M;Nlandu, Q;Heijnert, J;Bindels, E;Hoogenboezem, R;Mooren, F;Kuppe, C;Miesen, P;Grünberg, K;Ijzermans, T;Steenbergen, E;Czogalla, J;Schreuder, M;Sommerdijk, N;Akiva, A;Boor, P;Puelles, V;Floege, J;Huber, T;van Rij, R;Costa, I;Schneider, R;Smeets, B;Kramann, R;
| DOI: 10.1016/j.stem.2021.12.010
Kidney failure is frequently observed during and after COVID-19, but it remains elusive whether this is a direct effect of the virus. Here, we report that SARS-CoV-2 directly infects kidney cells and is associated with increased tubule-interstitial kidney fibrosis in patient autopsy samples. To study direct effects of the virus on the kidney independent of systemic effects of COVID-19, we infected human induced pluripotent stem cell-derived kidney organoids with SARS-CoV-2. Single cell RNA-sequencing indicated injury and dedifferentiation of infected cells with activation of pro-fibrotic signaling pathways. Importantly, SARS-CoV-2 infection also led to increased collagen 1 protein expression in organoids. A SARS-CoV-2 protease inhibitor was able to ameliorate the infection of kidney cells by SARS-CoV-2. Our results suggest that SARS-CoV-2 can directly infect kidney cells and induce cell injury with subsequent fibrosis. These data could explain both acute kidney injury in COVID-19 patients and the development of chronic kidney disease in Long-COVID.
SARS-CoV-2 infection of the oral cavity and saliva
Huang, N;Pérez, P;Kato, T;Mikami, Y;Okuda, K;Gilmore, RC;Conde, CD;Gasmi, B;Stein, S;Beach, M;Pelayo, E;Maldonado, JO;Lafont, BA;Jang, SI;Nasir, N;Padilla, RJ;Murrah, VA;Maile, R;Lovell, W;Wallet, SM;Bowman, NM;Meinig, SL;Wolfgang, MC;Choudhury, SN;Novotny, M;Aevermann, BD;Scheuermann, RH;Cannon, G;Anderson, CW;Lee, RE;Marchesan, JT;Bush, M;Freire, M;Kimple, AJ;Herr, DL;Rabin, J;Grazioli, A;Das, S;French, BN;Pranzatelli, T;Chiorini, JA;Kleiner, DE;Pittaluga, S;Hewitt, SM;Burbelo, PD;Chertow, D;NIH COVID-19 Autopsy Consortium, ;HCA Oral and Craniofacial Biological Network, ;Frank, K;Lee, J;Boucher, RC;Teichmann, SA;Warner, BM;Byrd, KM;
PMID: 33767405 | DOI: 10.1038/s41591-021-01296-8
Despite signs of infection-including taste loss, dry mouth and mucosal lesions such as ulcerations, enanthema and macules-the involvement of the oral cavity in coronavirus disease 2019 (COVID-19) is poorly understood. To address this, we generated and analyzed two single-cell RNA sequencing datasets of the human minor salivary glands and gingiva (9 samples, 13,824 cells), identifying 50 cell clusters. Using integrated cell normalization and annotation, we classified 34 unique cell subpopulations between glands and gingiva. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral entry factors such as ACE2 and TMPRSS members were broadly enriched in epithelial cells of the glands and oral mucosae. Using orthogonal RNA and protein expression assessments, we confirmed SARS-CoV-2 infection in the glands and mucosae. Saliva from SARS-CoV-2-infected individuals harbored epithelial cells exhibiting ACE2 and TMPRSS expression and sustained SARS-CoV-2 infection. Acellular and cellular salivary fractions from asymptomatic individuals were found to transmit SARS-CoV-2 ex vivo. Matched nasopharyngeal and saliva samples displayed distinct viral shedding dynamics, and salivary viral burden correlated with COVID-19 symptoms, including taste loss. Upon recovery, this asymptomatic cohort exhibited sustained salivary IgG antibodies against SARS-CoV-2. Collectively, these data show that the oral cavity is an important site for SARS-CoV-2 infection and implicate saliva as a potential route of SARS-CoV-2 transmission.
Residual SARS-CoV-2 viral antigens detected in GI and hepatic tissues from five recovered patients with COVID-19
Cheung, CCL;Goh, D;Lim, X;Tien, TZ;Lim, JCT;Lee, JN;Tan, B;Tay, ZEA;Wan, WY;Chen, EX;Nerurkar, SN;Loong, S;Cheow, PC;Chan, CY;Koh, YX;Tan, TT;Kalimuddin, S;Tai, WMD;Ng, JL;Low, JG;Yeong, J;Lim, KH;
PMID: 34083386 | DOI: 10.1136/gutjnl-2021-324280