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.
Cerebellar spreading depolarization mediates paroxysmal movement disorder
Lu, B;Lou, SS;Xu, RS;Kong, DL;Wu, RJ;Zhang, J;Zhuang, L;Wu, XM;He, JY;Wu, ZY;Xiong, ZQ;
PMID: 34551285 | DOI: 10.1016/j.celrep.2021.109743
Paroxysmal kinesigenic dyskinesia (PKD) is the most common paroxysmal dyskinesia, characterized by recurrent episodes of involuntary movements provoked by sudden changes in movement. Proline-rich transmembrane protein 2 (PRRT2) has been identified as the major causative gene for PKD. Here, we report that PRRT2 deficiency facilitates the induction of cerebellar spreading depolarization (SD) and inhibition of cerebellar SD prevents the occurrence of dyskinetic movements. Using Ca2+ imaging, we show that cerebellar SD depolarizes a large population of cerebellar granule cells and Purkinje cells in Prrt2-deficient mice. Electrophysiological recordings further reveal that cerebellar SD blocks Purkinje cell spiking and disturbs neuronal firing of the deep cerebellar nuclei (DCN). The resultant aberrant firing patterns in DCN are tightly, temporally coupled to dyskinetic episodes in Prrt2-deficient mice. Cumulatively, our findings uncover a pivotal role of cerebellar SD in paroxysmal dyskinesia, providing a potent target for treating PRRT2-related paroxysmal disorders.
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.
Somatostatin-expressing parafacial neurons are CO2/H+ sensitive and regulate baseline breathing
Cleary, CM;Milla, BM;Kuo, FS;James, S;Flynn, WF;Robson, P;Mulkey, DK;
PMID: 34013884 | DOI: 10.7554/eLife.60317
Glutamatergic neurons in the retrotrapezoid nucleus (RTN) function as respiratory chemoreceptors by regulating breathing in response to tissue CO2/H+. The RTN and greater parafacial region may also function as a chemosensing network composed of CO2/H+-sensitive excitatory and inhibitory synaptic interactions. In the context of disease, we showed that loss of inhibitory neural activity in a mouse model of Dravet syndrome disinhibited RTN chemoreceptors and destabilized breathing (Kuo et al., 2019). Despite this, contributions of parafacial inhibitory neurons to control of breathing are unknown, and synaptic properties of RTN neurons have not been characterized. Here, we show the parafacial region contains a limited diversity of inhibitory neurons including somatostatin (Sst)-, parvalbumin (Pvalb)-, and cholecystokinin (Cck)-expressing neurons. Of these, Sst-expressing interneurons appear uniquely inhibited by CO2/H+. We also show RTN chemoreceptors receive inhibitory input that is withdrawn in a CO2/H+-dependent manner, and chemogenetic suppression of Sst+ parafacial neurons, but not Pvalb+ or Cck+ neurons, increases baseline breathing. These results suggest Sst-expressing parafacial neurons contribute to RTN chemoreception and respiratory activity.
Long-term functional alterations following prenatal GLP-1R activation
Neurotoxicology and teratology
Graham, DL;Madkour, HS;Noble, BL;Schatschneider, C;Stanwood, GD;
PMID: 33864929 | DOI: 10.1016/j.ntt.2021.106984
Evidence supporting the use of glucagon-like peptide-1 (GLP-1) analogues to pharmacologically treat disorders beyond type 2 diabetes and obesity is increasing. However, little is known about how activation of the GLP-1 receptor (GLP-1R) during pregnancy affects maternal and offspring outcomes. We treated female C57Bl/6 J mice prior to conception and throughout gestation with a long-lasting GLP-1R agonist, Exendin-4. While GLP-1R activation has significant effects on food and drug reward, depression, locomotor activity, and cognition in adults, we found few changes in these domains in exendin-4-exposed offspring. Repeated injections of Exendin-4 had minimal effects on the dams and may have enhanced maternal care. Offspring exposed to the drug weighed significantly more than their control counterparts during the preweaning period and demonstrated alterations in anxiety-like outcomes, which indicate a developmental role for GLP-1R modulation in the stress response that may be sex-specific.
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.
Shi Y, Stornetta RL, Stornetta DS, Onengut-Gumuscu S, Farber EA, Turner SD, Guyenet PG, Bayliss DA.
PMID: 29066557 | DOI: 10.1523/JNEUROSCI.2055-17.2017
The retrotrapezoid nucleus (RTN) consists, by definition, of Phox2b-expressing, glutamatergic, non-catecholaminergic, non-cholinergic neurons located in the parafacial region of the medulla oblongata. An unknown proportion of RTN neurons are central respiratory chemoreceptors and there is mounting evidence for biochemical diversity among these cells. Here, we used multiplexed in situ hybridization and single-cell RNA-Seq in male and female mice to provide a more comprehensive view of the phenotypic diversity of RTN neurons. We now demonstrate that the RTN of mice can be identified with a single and specific marker, Nmb mRNA. Most (∼75%) RTN neurons express low-to-moderate levels of Nmb and display chemoreceptor properties. Namely they are activated by hypercapnia, but not by hypoxia, and express proton sensors, Kcnk5 and Gpr4 These Nmb-low RTN neurons also express varying levels of transcripts for Gal, Penk and Adcyap1,and receptors for substance P, orexin, serotonin and ATP. A subset of RTN neurons (∼20-25%), typically larger than average, express very high levels of Nmb mRNA. These Nmb-high RTN neurons do not express Fos after hypercapnia, have low-to-undetectable levels of Kcnk5 or Gpr4 transcripts; they also express Adcyap1, but are essentially devoid of Penk and Gal transcripts. In male rats, Nmb is also a marker of the RTN but, unlike in mice, this gene is expressed by other types of nearby neurons located within the ventromedial medulla. In sum, Nmb is a selective marker of the RTN in rodents; Nmb-low neurons, the vast majority, are central respiratory chemoreceptors whereas Nmb-high neurons likely have other functions.SIGNIFICANCE STATEMENTCentral respiratory chemoreceptors regulate arterial PCO2 by adjusting lung ventilation. Such cells have recently been identified within the retrotrapezoid nucleus (RTN), a brainstem nucleus defined by genetic lineage and a cumbersome combination of markers. Using single-cell RNA-Seq and multiplexed in situ hybridization, we show here that a single marker, Neuromedin B mRNA (Nmb), identifies RTN neurons in rodents. We also suggest that >75% of these Nmb neurons are chemoreceptors because they are strongly activated by hypercapnia and express high levels of proton sensors (Kcnk5 and Gpr4). The other RTN neurons express very high levels of Nmb, but low levels of Kcnk5/Gpr4/pre-pro-galanin/pre-pro-enkephalin, and do not respond to hypercapnia. Their function is unknown.
Golden, JW;Li, R;Cline, CR;Zeng, X;Mucker, EM;Fuentes-Lao, AJ;Spik, KW;Williams, JA;Twenhafel, N;Davis, N;Moore, JL;Stevens, S;Blue, E;Garrison, AR;Larson, DD;Stewart, R;Kunzler, M;Liu, Y;Wang, Z;Hooper, JW;
PMID: 35073750 | DOI: 10.1128/mbio.02906-21
The rapid emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a global health emergency. While most human disease is mild to moderate, some infections lead to a severe disease characterized by acute respiratory distress, hypoxia, anosmia, ageusia, and, in some instances, neurological involvement. Small-animal models reproducing severe disease, including neurological sequela, are needed to characterize the pathophysiological mechanism(s) of disease and to identify medical countermeasures. Transgenic mice expressing the human angiotensin-converting enzyme 2 (hACE2) viral receptor under the control of the K18 promoter develop severe and lethal respiratory disease subsequent to SARS-CoV-2 intranasal challenge when high viral doses are used. Here, we report on SARS-CoV-2 infection of hamsters engineered to express the hACE2 receptor under the control of the K18 promoter. K18-hACE2 hamsters infected with a relatively low dose of 100 or 1,000 PFU of SARS-CoV-2 developed a severe and lethal disease, with most animals succumbing by day 5 postinfection. Hamsters developed severe lesions and inflammation within the upper and lower respiratory system, including infection of the nasal cavities causing marked destruction of the olfactory epithelium as well as severe bronchopneumonia that extended deep into the alveoli. Additionally, SARS-CoV-2 infection spread to the central nervous system (CNS), including the brain stem and spinal cord. Wild-type (WT) hamsters naturally support SARS-CoV-2 infection, with the primary lesions present in the respiratory tract and nasal cavity. Overall, infection in the K18-hACE2 hamsters is more extensive than that in WT hamsters, with more CNS involvement and a lethal outcome. These findings demonstrate the K18-hACE2 hamster model will be valuable for studying SARS-CoV-2. IMPORTANCE The rapid emergence of SARS-CoV-2 has created a global health emergency. While most human SARS-CoV-2 disease is mild, some people develop severe, life-threatening disease. Small-animal models mimicking the severe aspects of human disease are needed to more clearly understand the pathophysiological processes driving this progression. Here, we studied SARS-CoV-2 infection in hamsters engineered to express the human angiotensin-converting enzyme 2 viral receptor under the control of the K18 promoter. SARS-CoV-2 produces a severe and lethal infection in transgenic hamsters that mirrors the most severe aspects of COVID-19 in humans, including respiratory and neurological injury. In contrast to other animal systems, hamsters manifest disease with levels of input virus more consistent with natural human infection. This system will be useful for the study of SARS-CoV-2 disease and the development of drugs targeting this virus.
Lahmer, T;Weirich, G;Porubsky, S;Rasch, S;Kammerstetter, F;Schustetter, C;Schüffler, P;Erber, J;Dibos, M;delbridge, c;kuhn, p;Jeske, S;steinhardt, m;Chaker, A;Heim, M;Heemann, U;Schmid, R;weichert, W;Stock, K;Slotta, J;
| DOI: 10.2139/ssrn.4464818
Methods: In this proof-of-concept study, we performed bedside ultrasound-guided minimally invasive autopsies (US-MIA) of patients that had died from critical COVID-19 in the intensive care unit (ICU) using a structured protocol to obtain almost autolytic-free tissue. Biopsies were assessed for quality (vitality and length) and for diagnosis. The efficiency of the procedure was monitored in five cases by recording the time of each step and safety issues by swabbing personal protective equipment and devices for viral contamination.
