La Manno G, Soldatov R, Zeisel A, Braun E, Hochgerner H, Petukhov V, Lidschreiber K, Kastriti ME, Lönnerberg P, Furlan A, Fan J, Borm LE, Liu Z, van Bruggen D, Guo J, He X, Barker R, Sundström E, Castelo-Branco G, Cramer P, Adameyko I, Linnarsson S, Kharc
PMID: 30089906 | DOI: 10.1038/s41586-018-0414-6
RNA abundance is a powerful indicator of the state of individual cells. Single-cell RNA sequencing can reveal RNA abundance with high quantitative accuracy, sensitivity and throughput1. However, this approach captures only a static snapshot at a point in time, posing a challenge for the analysis of time-resolved phenomena such as embryogenesis or tissue regeneration. Here we show that RNA velocity-the time derivative of the gene expression state-can be directly estimated by distinguishing between unspliced and spliced mRNAs in common single-cell RNA sequencing protocols. RNA velocity is a high-dimensional vector that predicts the future state of individual cells on a timescale of hours. We validate its accuracy in the neural crest lineage, demonstrate its use on multiple published datasets and technical platforms, reveal the branching lineage tree of the developing mouse hippocampus, and examine the kinetics of transcription in human embryonic brain. We expect RNA velocity to greatly aid the analysis of developmental lineages and cellular dynamics, particularly in humans.
Swanson, RV;Gupta, A;Foreman, TW;Lu, L;Choreno-Parra, JA;Mbandi, SK;Rosa, BA;Akter, S;Das, S;Ahmed, M;Garcia-Hernandez, ML;Singh, DK;Esaulova, E;Artyomov, MN;Gommerman, J;Mehra, S;Zuniga, J;Mitreva, M;Scriba, TJ;Rangel-Moreno, J;Kaushal, D;Khader, SA;
PMID: 37012543 | DOI: 10.1038/s41590-023-01476-3
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a global cause of death. Granuloma-associated lymphoid tissue (GrALT) correlates with protection during TB, but the mechanisms of protection are not understood. During TB, the transcription factor IRF4 in T cells but not B cells is required for the generation of the TH1 and TH17 subsets of helper T cells and follicular helper T (TFH)-like cellular responses. A population of IRF4+ T cells coexpress the transcription factor BCL6 during Mtb infection, and deletion of Bcl6 (Bcl6fl/fl) in CD4+ T cells (CD4cre) resulted in reduction of TFH-like cells, impaired localization within GrALT and increased Mtb burden. In contrast, the absence of germinal center B cells, MHC class II expression on B cells, antibody-producing plasma cells or interleukin-10-expressing B cells, did not increase Mtb susceptibility. Indeed, antigen-specific B cells enhance cytokine production and strategically localize TFH-like cells within GrALT via interactions between programmed cell death 1 (PD-1) and its ligand PD-L1 and mediate Mtb control in both mice and macaques.
Advanced science (Weinheim, Baden-Wurttemberg, Germany)
Yi, T;Wang, N;Huang, J;Wang, Y;Ren, S;Hu, Y;Xia, J;Liao, Y;Li, X;Luo, F;Ouyang, Q;Li, Y;Zheng, Z;Xiao, Q;Ren, R;Yao, Z;Tang, X;Wang, Y;Chen, X;He, C;Li, H;Hu, Z;
PMID: 36961096 | DOI: 10.1002/advs.202300189
Sevoflurane has been the most widely used inhaled anesthetics with a favorable recovery profile; however, the precise mechanisms underlying its anesthetic action are still not completely understood. Here the authors show that sevoflurane activates a cluster of urocortin 1 (UCN1+ )/cocaine- and amphetamine-regulated transcript (CART+ ) neurons in the midbrain involved in its anesthesia. Furthermore, growth hormone secretagogue receptor (GHSR) is highly enriched in sevoflurane-activated UCN1+ /CART+ cells and is necessary for sleep induction. Blockade of GHSR abolishes the excitatory effect of sevoflurane on UCN1+ /CART+ neurons and attenuates its anesthetic effect. Collectively, their data suggest that anesthetic action of sevoflurane necessitates the GHSR activation in midbrain UCN1+ /CART+ neurons, which provides a novel target including the nucleus and receptor in the field of anesthesia.
Nature biomedical engineering
Wang, Z;Popowski, KD;Zhu, D;de Juan Abad, BL;Wang, X;Liu, M;Lutz, H;De Naeyer, N;DeMarco, CT;Denny, TN;Dinh, PC;Li, Z;Cheng, K;
PMID: 35788687 | DOI: 10.1038/s41551-022-00902-5
The first two mRNA vaccines against infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that were approved by regulators require a cold chain and were designed to elicit systemic immunity via intramuscular injection. Here we report the design and preclinical testing of an inhalable virus-like-particle as a COVID-19 vaccine that, after lyophilisation, is stable at room temperature for over three months. The vaccine consists of a recombinant SARS-CoV-2 receptor-binding domain (RBD) conjugated to lung-derived exosomes which, with respect to liposomes, enhance the retention of the RBD in both the mucus-lined respiratory airway and in lung parenchyma. In mice, the vaccine elicited RBD-specific IgG antibodies, mucosal IgA responses and CD4+ and CD8+ T cells with a Th1-like cytokine expression profile in the animals' lungs, and cleared them of SARS-CoV-2 pseudovirus after a challenge. In hamsters, two doses of the vaccine attenuated severe pneumonia and reduced inflammatory infiltrates after a challenge with live SARS-CoV-2. Inhalable and room-temperature-stable virus-like particles may become promising vaccine candidates.
Expert review of vaccines
Neil, JA;Griffith, M;Godfrey, DI;Purcell, DFJ;Deliyannis, G;Jackson, D;Rockman, S;Subbarao, K;Nolan, T;
PMID: 35652289 | DOI: 10.1080/14760584.2022.2071264
Evaluation of immunogenicity and efficacy in animal models provide critical data in vaccine development. Nonhuman primates (NHPs) have been used extensively in the evaluation of SARS-CoV-2 vaccines.A critical synthesis of SARS-CoV-2 vaccine development with a focus on challenge studies in NHPs is provided. The benefits and drawbacks of the NHP models are discussed. The citations were selected by the authors based on PubMed searches of the literature, summaries from national public health bodies, and press-release information provided by vaccine developers.We identify several aspects of NHP models that limit their usefulness for vaccine-challenge studies and numerous variables that constrain comparisons across vaccine platforms. We propose that studies conducted in NHPs for vaccine development should use a standardized protocol and, where possible, be substituted with smaller animal models. This will ensure continued rapid progression of vaccines to clinical trials without compromising assessments of safety or efficacy.
Pathology - Research and Practice
Schwab, C;Domke, L;Rose, F;Hausser, I;Schirmacher, P;Longerich, T;
| DOI: 10.1016/j.prp.2022.154000
Pulmonary capillary microthrombosis has been proposed as a major pathogenetic factor driving severe COVID-19. Autopsy studies reported endothelialitis but it is under debate if it is caused by SARS-CoV-2 infection of endothelial cells. In this study, RNA in situ hybridization was used to detect viral RNA and to identify the infected cell types in lung tissue of 40 patients with fatal COVID-19. SARS-CoV-2 Spike protein-coding RNA showed a steadily decreasing signal abundance over a period of three weeks. Besides the original virus strain the variants of concern Alpha (B.1.1.7), Delta (B.1.617.2), and Omicron (B.1.1.529) could also be detected by the assay. Viral RNA was mainly detected in alveolar macrophages and pulmonary epithelial cells, while only single virus-positive endothelial cells were observed even in cases with high viral load suggesting that viral infection of endothelial cells is not a key factor for the development of pulmonary capillary microthrombosis.
Cellular & molecular immunology
Wang, Z;Lv, J;Yu, P;Qu, Y;Zhou, Y;Zhou, L;Zhu, Q;Li, S;Song, J;Deng, W;Gao, R;Liu, Y;Liu, J;Tong, WM;Qin, C;Huang, B;
PMID: 34983944 | DOI: 10.1038/s41423-021-00813-6
Exploring the cross-talk between the immune system and advanced biomaterials to treat SARS-CoV-2 infection is a promising strategy. Here, we show that ACE2-overexpressing A549 cell-derived microparticles (AO-MPs) are a potential therapeutic agent against SARS-CoV-2 infection. Intranasally administered AO-MPs dexterously navigate the anatomical and biological features of the lungs to enter the alveoli and are taken up by alveolar macrophages (AMs). Then, AO-MPs increase the endosomal pH but decrease the lysosomal pH in AMs, thus escorting bound SARS-CoV-2 from phago-endosomes to lysosomes for degradation. This pH regulation is attributable to oxidized cholesterol, which is enriched in AO-MPs and translocated to endosomal membranes, thus interfering with proton pumps and impairing endosomal acidification. In addition to promoting viral degradation, AO-MPs also inhibit the proinflammatory phenotype of AMs, leading to increased treatment efficacy in a SARS-CoV-2-infected mouse model without side effects. These findings highlight the potential use of AO-MPs to treat SARS-CoV-2-infected patients and showcase the feasibility of MP therapies for combatting emerging respiratory viruses in the future.
Han, Y;Yuan, K;Wang, Z;Liu, WJ;Lu, ZA;Liu, L;Shi, L;Yan, W;Yuan, JL;Li, JL;Shi, J;Liu, ZC;Wang, GH;Kosten, T;Bao, YP;Lu, L;
PMID: 34593760 | DOI: 10.1038/s41398-021-01629-8
The coronavirus disease 2019 (COVID-19) pandemic has caused large-scale economic and social losses and worldwide deaths. Although most COVID-19 patients have initially complained of respiratory insufficiency, the presence of neuropsychiatric manifestations is also reported frequently, ranging from headache, hyposmia/anosmia, and neuromuscular dysfunction to stroke, seizure, encephalopathy, altered mental status, and psychiatric disorders, both in the acute phase and in the long term. These neuropsychiatric complications have emerged as a potential indicator of worsened clinical outcomes and poor prognosis, thus contributing to mortality in COVID-19 patients. Their etiology remains largely unclear and probably involves multiple neuroinvasive pathways. Here, we summarize recent animal and human studies for neurotrophic properties of severe acute respiratory syndrome coronavirus (SARS-CoV-2) and elucidate potential neuropathogenic mechanisms involved in the viral invasion of the central nervous system as a cause for brain damage and neurological impairments. We then discuss the potential therapeutic strategy for intervening and preventing neuropsychiatric complications associated with SARS-CoV-2 infection. Time-series monitoring of clinical-neurochemical-radiological progress of neuropsychiatric and neuroimmune complications need implementation in individuals exposed to SARS-CoV-2. The development of a screening, intervention, and therapeutic framework to prevent and reduce neuropsychiatric sequela is urgently needed and crucial for the short- and long-term recovery of COVID-19 patients.
Introduction of synaptotagmin 7 promotes facilitation at the climbing fiber to Purkinje cell synapse
Weyrer, C;Turecek, J;Harrison, B;Regehr, WG;
PMID: 34551307 | DOI: 10.1016/j.celrep.2021.109719
Synaptotagmin 7 (Syt7) is a high-affinity calcium sensor that is implicated in multiple aspects of synaptic transmission. Here, we study the influence of Syt7 on the climbing fiber (CF) to Purkinje cell (PC) synapse. We find that small facilitation and prominent calcium-dependent recovery from depression at this synapse do not rely on Syt7 and that Syt7 is not normally present in CFs. We expressed Syt7 in CFs to assess the consequences of introducing Syt7 to a synapse that normally lacks Syt7. Syt7 expression does not promote asynchronous release or accelerate recovery from depression. Syt7 decreases the excitatory postsynaptic current (EPSC) magnitude, consistent with a decrease in the initial probability of release (PR). Syt7 also increases synaptic facilitation to such a large extent that it could not arise solely as an indirect consequence of decreased PR. Thus, the primary consequence of Syt7 expression in CFs, which normally lack Syt7, is to promote synaptic facilitation.
LB740 SARS-CoV-2-associated ‘covid toes:’ multiplex immunofluorescent characterization of pathophysiology
Journal of Investigative Dermatology
Moon, J;Costa da Silva, A;Tran, J;Kim, C;Sharma, R;Hinshaw, M;Shields, B;Brooks, E;Cowen, E;Singh, A;Drolet, B;Mays, J;Arkin, L;
| DOI: 10.1016/j.jid.2021.07.093
Coincident with the start of the COVID-19 pandemic, dermatologists worldwide have reported an uncharacteristic increase in pernio or chilblains (aka ‘COVID toes’). However, the lack of systemic illness, low PCR positivity and lack of consistent seroconversion have led some authors to postulate an epiphenomenon. SARS-CoV-2 spike protein has been identified in a limited number of skin biopsies in few publications, yet there remain conflicting reports regarding other SARS-CoV-2 associated proteins, the presence or absence of viral RNA, and a unifying pathophysiology. In cooperation with the COVID Human Genome Effort, our “COVID toes” biobank was established to identify both the genetic and immunologic basis and provide clinically relevant insights into targeted therapeutics. As of March 2021, we have enrolled 96 patients, creating a prospective biorepository with clinical data, saliva, serial blood collection, and skin biopsies. Here we aim to comprehensively investigate the conflicting findings, detail the inflammatory response, and identify the source of interferon signaling with multiplex immunofluorescence (IFA) and the RNAscope fluorescent assay to detect viral mRNA. Median patient age was 17 (range 2 e 72) and 44/96 (46%) were male. Preliminary IFA results demonstrate detection of SARS-CoV-2 components, robust MxA detection and plasmacytoid dendritic cell (pDC) colocalization, identifying PDCs as the likely primary source of IFN-I production and implicates an excessive localized IFN-I response in affected patients.
Halfmann, PJ;Iida, S;Iwatsuki-Horimoto, K;Maemura, T;Kiso, M;Scheaffer, SM;Darling, TL;Joshi, A;Loeber, S;Singh, G;Foster, SL;Ying, B;Case, JB;Chong, Z;Whitener, B;Moliva, J;Floyd, K;Ujie, M;Nakajima, N;Ito, M;Wright, R;Uraki, R;Warang, P;Gagne, M;Li, R;Sakai-Tagawa, Y;Liu, Y;Larson, D;Osorio, JE;Hernandez-Ortiz, JP;Henry, AR;Ciouderis, K;Florek, KR;Patel, M;Odle, A;Wong, LR;Bateman, AC;Wang, Z;Edara, VV;Chong, Z;Franks, J;Jeevan, T;Fabrizio, T;DeBeauchamp, J;Kercher, L;Seiler, P;Gonzalez-Reiche, AS;Sordillo, EM;Chang, LA;van Bakel, H;Simon, V;Consortium Mount Sinai Pathogen Surveillance (PSP) study group, ;Douek, DC;Sullivan, NJ;Thackray, LB;Ueki, H;Yamayoshi, S;Imai, M;Perlman, S;Webby, RJ;Seder, RA;Suthar, MS;García-Sastre, A;Schotsaert, M;Suzuki, T;Boon, ACM;Diamond, MS;Kawaoka, Y;
PMID: 35062015 | DOI: 10.1038/s41586-022-04441-6
The recent emergence of B.1.1.529, the Omicron variant1,2 has raised concerns for escape from protection by vaccines and therapeutic antibodies. A key test for potential countermeasures against B.1.1.529 is their activity in pre-clinical rodent models of respiratory tract disease. Here, using the collaborative network of the SARS-CoV-2 Assessment of Viral Evolution (SAVE) program of the National Institute of Allergy and Infectious Diseases (NIAID), we evaluated the ability of multiple B.1.1.529 Omicron isolates to cause infection and disease in immunocompetent and human ACE2 (hACE2) expressing mice and hamsters. Despite modeling data suggesting that B.1.1.529 spike can bind more avidly to murine ACE23,4, we observed less infection in 129, C57BL/6, BALB/c, and K18-hACE2 transgenic mice as compared with previous SARS-CoV-2 variants, with limited weight loss and lower viral burden in the upper and lower respiratory tracts. In wild-type and hACE2 transgenic hamsters, lung infection, clinical disease, and pathology with B.1.1.529 also were milder compared to historical isolates or other SARS-CoV-2 variants of concern. Overall, experiments from the SAVE/NIAID network with several B.1.1.529 isolates demonstrate attenuated lung disease in rodents, which parallels preliminary human clinical data.
Bilateral Chilblain-like Lesions of the Toes Characterized by Microvascular Remodeling in Adolescents During the COVID-19 Pandemic
Discepolo, V;Catzola, A;Pierri, L;Mascolo, M;Della Casa, F;Vastarella, M;Smith, G;Travaglino, A;Punziano, A;Nappa, P;Staibano, S;Bruzzese, E;Fabbrocini, G;Guarino, A;Alessio, M;
PMID: 34110396 | DOI: 10.1001/jamanetworkopen.2021.11369
Chilblain-like lesions have been one of the most frequently described cutaneous manifestations during the COVID-19 pandemic. Their etiopathogenesis, including the role of SARS-CoV-2, remains elusive.To examine the association of chilblain-like lesions with SARS-CoV-2 infection.This prospective case series enrolled 17 adolescents who presented with chilblain-like lesions from April 1 to June 30, 2020, at a tertiary referral academic hospital in Italy.Macroscopic (clinical and dermoscopic) and microscopic (histopathologic) analysis contributed to a thorough understanding of the lesions. Nasopharyngeal swab, serologic testing, and in situ hybridization of the skin biopsy specimens were performed to test for SARS-CoV-2 infection. Laboratory tests explored signs of systemic inflammation or thrombophilia. Structural changes in peripheral microcirculation were investigated by capillaroscopy.Of the 17 adolescents (9 [52.9%] male; median [interquartile range] age, 13.2 [12.5-14.3] years) enrolled during the first wave of the COVID-19 pandemic, 16 (94.1%) had bilaterally localized distal erythematous or cyanotic lesions. A triad of red dots (16 [100%]), white rosettes (11 [68.8%]), and white streaks (10 [62.5%]) characterized the dermoscopic picture. Histologic analysis revealed a remodeling of the dermal blood vessels with a lobular arrangement, wall thickening, and a mild perivascular lymphocytic infiltrate. SARS-CoV-2 infection was excluded by molecular and serologic testing. In situ hybridization did not highlight the viral genome in the lesions.This study delineated the clinical, histologic, and laboratory features of chilblain-like lesions that emerged during the COVID-19 pandemic, and its findings do not support their association with SARS-CoV-2 infection. The lesions occurred in otherwise healthy adolescents, had a long but benign course to self-resolution, and were characterized by a microvascular remodeling with perivascular lymphocytic infiltrate but no other signs of vasculitis. These results suggest that chilblain-like lesions do not imply a concomitant SARS-CoV-2 infection. Ongoing studies will help clarify the etiopathogenic mechanisms.
