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Hypothalamic REV-ERB nuclear receptors control diurnal food intake and leptin sensitivity in diet-induced obese mice

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Abstract

Obesity occurs when energy expenditure is outweighed by energy intake. Tuberal hypothalamic nuclei, including the arcuate nucleus (ARC), ventromedial nucleus (VMH), and dorsomedial nucleus (DMH), control for food intake and energy expenditure. Here we reported that, contrary to females, male mice lacking circadian nuclear receptors REV-ERB alpha and beta in the tuberal hypothalamus (HDKO) gained excessive weight on an obesogenic high fat diet due to both decreased energy expenditure and increased food intake during the light phase. Moreover, rebound food intake after fasting was markedly increased in HDKO mice. Integrative transcriptomic and cistromic analyses revealed that such disruption in feeding behavior was due to perturbed REV-ERB-dependent leptin signaling in the ARC. Indeed, in vivo leptin sensitivity was impaired in HDKO mice on an obesogenic diet in a diurnal manner. Thus, REV-ERBs play a crucial role in hypothalamic control of food intake and diurnal leptin sensitivity in diet-induced obesity.

Authors

Marine Adlanmerini, Hoang C. B. Nguyen, Brianna M. Krusen, Clare W. Teng, Caroline E. Geisler, Lindsey C. Peed, Bryce J. Carpenter, Matthew R. Hayes, Mitchell A. Lazar

Ventromedial hypothalamic primary cilia control energy and skeletal homeostasis

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Abstract

Dysfunction of primary cilia is related to dyshomeostasis, leading to a wide range of disorders. The ventromedial hypothalamus (VMH) is known to regulate several homeostatic processes, but those modulated specifically by VMH-primary cilia are not yet known. In this study, we identify VMH-primary cilia as an important organelle that maintains energy and skeletal homeostasis by modulating the autonomic nervous system. We established loss-of-function models of primary cilia in the VMH by either targeting IFT88 (IFT88 KOSF-1) using steroidogenic factor 1-Cre (SF1-Cre) or injecting an adeno-associated virus Cre (AAV-Cre) directly into the VMH. Functional impairments of VMH-primary cilia were linked to decreased sympathetic activation and central leptin resistance, which led to marked obesity and bone density accrual. Obesity was caused by hyperphagia, decreased energy expenditure, and blunted brown fat function, as well as associated with insulin and leptin resistance. The effect of bone density accrual was independent from obesity, as it was caused by the decreased sympathetic tone resulting in increased osteoblastic and decreased osteoclastic activities in the IFT88 KOSF-1 and VMH-primary cilia knock-down mice. Overall, our current study identifies VMH-primary cilia as a critical hypothalamic organelle that maintains energy and skeletal homeostasis.

Authors

Ji Su Sun, Dong Joo Yang, Ann W. Kinyua, Seul Gi Yoon, Je Kyung Seong, Juwon Kim, Seok Jun Moon, Dong Min Shin, Yun-Hee Choi, Ki Woo Kim

Promoting the success of women and minority physician-scientists in academic medicine: a dean’s perspective

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Abstract

Dr. Nancy Brown, Dean of the Yale School of Medicine, shares her perspective on the challenges facing women and minority faculty members and trainees in academic medicine and provides a reflection on how leaders in academic medicine can promote diversity, equity, and inclusion to enhance their success.

Authors

Nancy J. Brown

COVID-19 and myeloid cells: complex interplay correlates with lung severity

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Abstract

COVID-19 spans and wide range of symptoms, sometimes with profound immune system involvement. How immune cell subsets change during the disease course and with disease severity needs further study. While myeloid cells have been shown to initiate and maintain responses to pneumonia and lung inflammation, often playing a role in resolution, their involvement with COVID-19 remains unknown. In this issue of the JCI, Sánchez-Cerrillo and Pedro-Landete et al. investigated dendritic cells and monocytes from blood and bronchial secretions of patients with varying COVID-19 severity and with healthy controls. The authors conclude that circulating monocytes and DCs migrate from the blood into the inflamed lungs. While sampling differences in sex, collection timing, bacteria/fungal infection, and corticosteroid treatment limit interpretation, we believe that reprograming monocyte or macrophages by targeting immunometabolism, epigenetics, or the cytokine milieu holds promise in resolving lung-inflammation associated with COVID-19.

Authors

Franco R. D'Alessio, Nicola M. Heller

Transcriptome-directed analysis for Mendelian disease diagnosis overcomes limitations of conventional genomic testing

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Abstract

BACKGROUND. Transcriptome sequencing (RNA-seq) improves diagnostic rates in individuals with suspected Mendelian conditions to varying degrees, primarily by directing the prioritization of candidate DNA variants identified on exome or genome sequencing (ES/GS). Here we implemented an RNA-seq guided method to diagnose individuals across a wide range of ages and clinical phenotypes. METHODS. One hundred fifteen undiagnosed adult and pediatric patients with diverse phenotypes and 67 family members (182 total individuals) underwent RNA-seq from whole blood and fibroblasts at the Baylor College of Medicine (BCM) Undiagnosed Diseases Network (UDN) clinical site from 2014-2020. We implemented a workflow to detect outliers in gene expression and splicing for cases that remained undiagnosed despite standard genomic and transcriptomic analysis. RESULTS. The transcriptome-directed approach resulted in a diagnostic rate of 12% across the entire cohort, or 17% after excluding cases solved on ES/GS alone. Newly diagnosed conditions included Koolen-de Vries syndrome (KANSL1), Renpenning syndrome (PQBP1), TBCK-associated encephalopathy, NSD2- and CLTC-related intellectual disability, and others, all with negative conventional genomic testing, including ES and chromosomal microarray (CMA). Fibroblasts exhibited higher and more consistent expression of clinically relevant genes than whole blood. In solved cases with RNA-seq from both tissues, the causative defect was missed in blood in half the cases but none from fibroblasts. CONCLUSION. For our cohort of undiagnosed individuals with suspected Mendelian conditions, transcriptome-directed genomic analysis facilitated diagnoses, primarily through the identification of variants missed on ES and CMA.

Authors

David R. Murdock, Hongzheng Dai, Lindsay C. Burrage, Jill A. Rosenfeld, Shamika Ketkar, Michaela F. Müller, Vicente A. Yépez, Julien Gagneur, Pengfei Liu, Shan Chen, Mahim Jain, Gladys Zapata, Carlos A. Bacino, Hsiao-Tuan Chao, Paolo Moretti, William J. Craigen, Neil A. Hanchard, Brendan Lee

Protein tyrosine phosphatase non-receptor type 2 controls colorectal cancer development

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Abstract

Protein tyrosine phosphatase non-receptor type 2 (PTPN2) recently emerged as a promising cancer immunotherapy target. We set to investigate the functional role of PTPN2 in the pathogenesis of human colorectal carcinoma (CRC) as its role in immune-silent solid tumors is poorly understood. We demonstrate that in human CRC, increased PTPN2 expression and activity correlated with disease progression and decreased immune responses in tumor tissues. Particularly, stage II and III tumors displayed enhanced PTPN2 protein expression in tumor-infiltrating T-cells and increased PTPN2 levels negatively correlated with PD1, CTLA4, STAT1 and granzyme A. In vivo, T-cell and dendritic cell-specific PTPN2 deletion reduced tumor burden in several CRC models by promoting CD44+ effector/memory T-cells, as well as CD8+ T-cell infiltration and cytotoxicity into the tumor. In direct relevance to CRC treatment, T-cell-specific PTPN2 deletion potentiated anti-PD-1 efficacy and induced anti-tumor memory formation upon tumor re-challenge in vivo. Our data suggest a role for PTPN2 in suppressing anti-tumor immunity and promoting tumor development in CRC patients. Our in vivo results uncover PTPN2 as a key player in controlling immunogenicity of CRC, with the strong potential to be exploited to promote cancer immunotherapy.

Authors

Egle Katkeviciute, Larissa Hering, Ana Montalban-Arques, Philipp Busenhart, Marlene Schwarzfischer, Roberto Manzini, Javier Conde, Kirstin Atrott, Silvia Lang, Gerhard Rogler, Elisabeth Naschberger, Vera S. Schellerer, Michael Stürzl, Andreas Rickenbacher, Matthias Turina, Achim Weber, Sebastian Leibl, Gabriel E. Leventhal, Mitchell Levesque, Onur Boyman, Michael Scharl, Marianne R. Spalinger

Recent endemic coronavirus infection is associated with less severe COVID-19

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Abstract

Four different endemic coronaviruses (eCoVs) are etiologic agents for the seasonal “common cold,” and these eCoVs share extensive sequence homology with human severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Here, we show that individuals with as compared to without a relatively recent documented eCoV were tested at greater frequency for respiratory infections but had similar rate of SARS-CoV-2 acquisition. Importantly, the patients with a previously detected eCoV had less severe coronavirus disease-2019 (COVID-19) illness. Our observations suggest that pre-existing immune responses against endemic human coronaviruses can mitigate disease manifestations from SARS-CoV-2 infection.

Authors

Manish Sagar, Katherine Reifler, Michael Rossi, Nancy S. Miller, Pranay Sinha, Laura White, Joseph P. Mizgerd

COVID-19 survival associates with the immunoglobulin response to the SARS-CoV-2 spike Receptor Binding Domain

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Abstract

BACKGROUND. Serological assays are of critical importance to investigate correlates of response and protection in COVID-19, to define previous exposure to SARS-CoV-2 in populations and to verify the development of an adaptive immune response in infected individuals. METHODS. We studied 509 confirmed COVID-19 patients from the San Raffaele Hospital of Milan and 480 pre-pandemic organ donor sera collected in 2010-2012. Using fluid-phase luciferase immune precipitation (LIPS) assays, we characterized IgG, IgM, IgA antibodies to the spike Receptor Binding Domain (RBD), S1+S2, nucleocapsid, and ORF6 to 10 of SARS-CoV-2, to the HCoV-OC43 and HCoV-HKU1 betacoronaviruses spike S2, and the H1N1Ca2009 flu virus hemagglutinin. Sequential samples at 1 and 3 months post-hospital discharge were also tested in 95 patients for SARS-CoV-2 RBD antibodies. RESULTS. Antibodies developed rapidly against multiple SARS-CoV-2 antigens in 95% of patients by 4 weeks post-symptoms onset and IgG to the RBD increased until the 3rd month of follow-up. We observed a major synchronous expansion of antibodies to the HCoV-OC43 and HCoV-HKU1 spike S2. A likely co-infection with influenza was neither linked to a more severe presentation of the disease nor to a worse outcome. Of the measured antibody responses positivity for IgG against the SARS-CoV-2 spike RBD was predictive of survival. CONCLUSIONS. The measurement of antibodies to selected epitopes of SARS-CoV-2 antigens can offer a more accurate assessment of the humoral response in patients and its impact on survival. The presence of partially cross-reactive antibodies with other betacoronoviruses is likely to impact on serological assay specificity and interpretation.

Authors

Massimiliano Secchi, Elena Bazzigaluppi, Cristina Brigatti, Ilaria Marzinotto, Cristina Tresoldi, Patrizia Rovere-Querini, Andrea Poli, Antonella Castagna, Gabriella Scarlatti, Alberto Zangrillo, Fabio Ciceri, Lorenzo Piemonti, Vito Lampasona

Endothelial C3a receptor mediates vascular inflammation and BBB permeability during aging

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Abstract

Dysfunction of immune and vascular systems has been implicated in aging and Alzheimer’s disease; however, their interrelatedness remains poorly understood. The complement pathway is a well-established regulator of innate immunity in the brain. Here, we report robust age-dependent increases in vascular inflammation, peripheral lymphocyte infiltration, and blood-brain barrier (BBB) permeability. These phenotypes were subdued by global inactivation and by endothelial-specific ablation of C3ar1. Using an in vitro model of the BBB, we identify intracellular Ca2+ as a downstream effector of C3a-C3aR signaling and a functional mediator of VE-cadherins junction and barrier integrity. Endothelial C3ar1 inactivation also dampened microglia reactivity and improved hippocampal and cortical volumes in the aging brain, demonstrating a crosstalk between brain vasculature dysfunction and immune cell activation and neurodegeneration. Further, prominent C3aR-dependent vascular inflammation is also observed in a tau transgenic mouse model. Our studies suggest that heightened C3a-C3aR signaling through endothelial cells promotes vascular inflammation and BBB dysfunction and contribute to overall neuroinflammation in aging and neurodegenerative disease.

Authors

Nicholas E. Propson, Ethan R. Roy, Alexandra Litvinchuk, Jorg Köhl, Hui Zheng

Brain immune cells undergo cGAS-STING-dependent apoptosis during herpes simplex virus type 1 infection

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Abstract

Protection of the brain from viral infections involves the type I interferon (IFN-I) system, defects in which renders humans susceptible to herpes simplex encephalitis (HSE). However, excessive cerebral IFN-I levels leads to pathologies, suggesting the need for tight regulation of responses. Based on data from mouse models, human HSE cases, and primary cell culture systems, we here show that microglia and other immune cells undergo apoptosis in the HSV-1-infected brain through a mechanism dependent on the cyclic GMP-AMP synthase (cGAS) - stimulator of interferon genes (STING) pathway, but independent of IFN-I. HSV-1 infection of microglia induced cGAS-dependent apoptosis at high viral doses, while lower viral doses led to IFN-I responses. Importantly, inhibition of caspase activity prevented microglial cell death and augmented IFN-I responses. Accordingly, HSV-1-infected organotypic brain slices, or mice treated with caspase inhibitor, exhibited lower viral load and improved outcome of infection. Collectively, we identify an activation-induced apoptosis program in brain immune cells which down-modulates local immune responses.

Authors

Line S. Reinert, Ahmad S. Rashidi, Diana N. Tran, Georgios Katzilieris-Petras, Astrid K. Hvidt, Mette Gohr, Stefanie Fruhwürth, Chiranjeevi Bodda, Martin K. Thomsen, Mikkel H. Vendelbo, Ahmad Raza Khan, Brian Hansen, Petra Bergström, Lotta Agholme, Trine H. Mogensen, Maria H. Christensen, Jens R. Nyengaard, Ganes C. Sen, Henrik Zetterberg, Georges M.G.M. Verjans, Soren R. Paluden

MAL2 drives immune evasion in breast cancer by suppressing tumor antigen presentation

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Abstract

Immune evasion is a pivotal event in tumor progression. To eliminate human cancer cells, current immune checkpoint therapy is set to boost the CD8+ T cell-mediated cytotoxicity. However, this action is eventually dependent on the efficient recognition of tumor-specific antigens via T cell receptors. One primary mechanism by which tumor cells evade immune surveillance is to downregulate their antigen presentation. Little progress has been made towards harnessing potential therapeutic targets for enhancing antigen presentation on the tumor cell. Here, we identified MAL2 as a key player that determines the turnover of the antigen-loaded MHC-I complex and reduces the antigen presentation on tumor cells. MAL2 promotes the endocytosis of tumor antigens via direct interaction with the MHC-I complex and endosome-associated RAB proteins. In preclinical models, depletion of MAL2 in breast tumor cells profoundly enhanced the cytotoxicity of tumor-infiltrating CD8+ T cells and suppressed breast tumor growth, suggesting that MAL2 is a potential therapeutic target for breast cancer immunotherapy.

Authors

Yuanzhang Fang, Lifei Wang, Changlin Wan, Yifan Sun, Kevin Van der Jeught, Zhuolong Zhou, Tianhan Dong, Ka Man So, Tao Yu, Yujing Li, Haniyeh Eyvani, Austyn Colter, Edward Dong, Sha Cao, Jin Wang, Bryan P. Schneider, George Sandusky, Yunlong Liu, Chi Zhang, Xiongbin Lu, Xinna Zhang

Tumor genotype dictates radiosensitization after Atm deletion in primary brainstem glioma models

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Abstract

Diffuse intrinsic pontine glioma (DIPG) kills more children than any other type of brain tumor. Despite clinical trials testing many chemotherapeutic agents, palliative radiotherapy remains the standard treatment. Here, we utilized Cre/loxP technology to show that deleting Ataxia telangiectasia mutated (Atm) in primary mouse models of DIPG can enhance tumor radiosensitivity. Genetic deletion of Atm improved survival of mice with p53 deficient but not p53 wild-type gliomas following radiotherapy. Similar to patients with DIPG, mice with p53 wild-type tumors had improved survival after radiotherapy independent of Atm deletion. Primary p53 wild-type tumor cell lines induced proapoptotic genes after radiation and repressed the NRF2 target, NAD(P)H quinone dehydrogenase 1 (Nqo1). Tumors lacking p53 and Ink4a/Arf expressed the highest level of Nqo1 and were most resistant to radiation, but deletion of Atm enhanced the radiation response. These results suggest that tumor genotype may determine whether inhibition of ATM during radiotherapy will be an effective clinical approach to treat DIPGs.

Authors

Katherine Deland, Bryce F. Starr, Joshua S. Mercer, Jovita Byemerwa, Donna M. Crabtree, Nerissa T. Williams, Lixia Luo, Yan Ma, Mark Chen, Oren J. Becher, David G Kirsch

Towards realizing diversity in academic medicine

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Abstract

Dr. John Carethers discusses challenges to the advancement of underrepresented minorities in medicine and effective strategies for institutions to promote diversity. He proposes that diversity should be a fourth pillar in the mission of academic medicine, alongside research, education, and clinical care.

Authors

John M. Carethers

Corticosteroids, COVID-19 pneumonia and acute respiratory distress syndrome

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Abstract

While corticosteroids dampen the dysregulated immune system and sometimes are prescribed as an adjunctive treatment for pneumonia, their effectiveness in the treatment of coronavirus 2019 (COVID-19) remains controversial. In this issue of the JCI, Liu and Zhang et al. evaluated corticosteroid treatment in more than 400 patients with severe COVID-19. The authors assessed subjects retrospectively for cardiac and liver injury, shock, ventilation, mortality, and viral clearance. Corticosteroids in severe COVID-19 related acute respiratory distress syndrome (ARDS) was associated with increased mortality and delayed viral clearance. Here, we consider how to reconcile the negative effects of corticosteroids revealed by Liu and Zhang et al. with the favorable effects (reduced mortality) that were described in the RECOVERY trial. We posit that treatment timing, dosage, and COVID-19 disease severity determine immune response and viral outcome. Patients with moderate-to-severe COVID-19 pneumonia are likely to benefit from moderate dose corticosteroid treatment when administered relatively late in the disease course.

Authors

Michael A. Matthay, Katherine D. Wick

Are T cells helpful for COVID-19: the relationship between response and risk

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Abstract

The disease spectrum of coronavirus disease 2019 (COVID-19) ranges from no symptoms to multisystem failure and death. Characterization of virus-specific immune responses to severe acute respiratory coronavirus 2 (SARS-CoV-2) is key to understanding disease pathogenesis, but few studies have evaluated T cell immunity. In this issue of the JCI, Sattler et al. sampled blood from subjects with COVID-19 and analyzed the activation and function of virus antigen-specific CD4+ T cells. T cells that failed to respond to peptides from the membrane, spike or nucleocapsid proteins were more common in subjects who died. In those whose T cells had the capacity to respond, older patients with more co-morbidity had larger numbers of activated T cells compared with patients that had fewer risk factors, but these cells showed impaired IFN- production. This cross-sectional study relates activated T cell responses to patient risk factors and outcome. However, T cell response trajectory over the disease course remains an open question.

Authors

Diane E. Griffin

Tobacco smoking induces metabolic reprogramming of renal cell carcinoma

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Abstract

Background. Clear cell renal cell carcinoma (ccRCC) is the most common histologically defined renal cancer. However, it is not a uniform disease and includes several genetic subtypes with different prognosis. ccRCC is also characterized by distinguished metabolic reprogramming. Tobacco smoking (TS) is an established risk factor for ccRCC with unknown effects on tumor pathobiology. Methods. We investigated the landscape of ccRCCs and paired normal kidney tissues (NKTs) using integrated transcriptomic, metabolomic and metallomic approaches in a cohort of never smokers (NS) and long-term current smokers (LTS) Caucasian males. Results. All three Omics domains consistentl identified a distinct metabolic subtype of ccRCCs in LTS, characterized by activation of oxidative phosphorylation (OxPhos) coupled with reprogramming of the malate-aspartate shuttle and metabolism of aspartate, glutamate, glutamine and histidine. Cadmium, copper and inorganic arsenic accumulated in LTS tumors showing redistribution among intracellular pools, including relocation of copper into the cytochrome c oxidase complex. Gene expression signature based on the LTS metabolic subtype provided prognostic stratification of The Cancer Genome Atlas (TCGA) ccRCC tumors that was independent from genomic alterations. Conclusions. The work identifies the TS related metabolic subtype of ccRCC with vulnerabilities that can be exploited for precision medicine approaches targeting metabolic pathways. The results provide rationale for the development of metabolic biomarkers with diagnostic and prognostic applications using evaluation of OxPhos status. The metallomic analysis reveals the role of disrupted metal homeostasis in ccRCC highlighting the importance of studying effects of metals from e-cigarettes and environmental exposures.

Authors

James Reigle, Dina Secic, Jacek Biesiada, Collin Wetzel, Behrouz Shamsaei, Johnson Chu, Yuanwei Zang, Xiang Zhang, Nicholas J. Talbot, Megan E. Bischoff, Yongzhen Zhang, Charuhas V. Thakar, Krishnanath Gaitonde, Abhinav Sidana, Hai Bui, John T. Cunningham, Qing Zhang, Laura S. Schmidt, W. Marston Linehan, Mario Medvedovic, David R. Plas, Julio A. Landero Figueroa, Jarek Meller, Maria F. Czyzyk-Krzeska

Cytomegalovirus viral load kinetics as surrogate endpoints after allogeneic transplantation

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Abstract

Background: Viral load surrogate endpoints transformed development of HIV and hepatitis C therapeutics. Surrogate endpoints for cytomegalovirus (CMV)-related morbidity and mortality could advance development of antiviral treatments. While observational data support using CMV viral load (VL) as a trial endpoint, randomized controlled trials (RCT) demonstrating direct associations between virologic markers and clinical endpoints are lacking. Methods: We performed CMV DNA polymerase chain reaction (PCR) on frozen serum samples from the only placebo-controlled RCT of ganciclovir for early treatment of CMV after hematopoietic cell transplantation (HCT). We used established criteria to assess VL kinetics as surrogates for CMV disease or death by weeks 8, 24, and 48 after randomization and quantified antiviral effects captured by each marker. We used ensemble-based machine learning to assess the predictive ability of VL kinetics and performed this analysis on a ganciclovir prophylaxis RCT for validation. Results: VL suppression with ganciclovir reduced cumulative incidence of CMV disease and death for 20 years after HCT. Mean VL, peak VL, and change in VL during the first five weeks of treatment fulfilled the Prentice definition for surrogacy, capturing > 95% of ganciclovir’s effect, and yielded highly sensitive and specific predictions by week 48. In the prophylaxis trial, viral shedding rate satisfied the Prentice definition for CMV disease by week 24. Conclusion: Our results support using CMV VL kinetics as surrogates for CMV disease, provide a framework for developing CMV preventative and therapeutic agents, and support reductions in viral load as the mechanism through which antivirals reduce CMV disease.

Authors

Elizabeth R. Duke, Brian D. Williamson, Bhavesh Borate, Jonathan L. Golob, Chiara Wychera, Terry Stevens-Ayers, Meei-Li Huang, Nicole Cossrow, Hong Wan, T. Christopher Mast, Morgan A. Marks, Mary Flowers, Keith R. Jerome, Lawrence Corey, Peter B. Gilbert, Joshua T. Schiffer, Michael Boeckh

Reflections of a Black woman physician-scientist

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Dr. Rotonya Carr provides her thoughts on being one of the only Black women in her field, the persistent race-gender gap among academic medical center faculty, and possible solutions to retaining and promoting Black women in academia.

Authors

Rotonya M. Carr

Healthy donor T-cell responses to common cold coronaviruses and SARS-CoV-2

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BACKGROUND. The T cell responses to the common cold coronaviruses have not been well characterized. Pre-existing T cell immunity to SARS-CoV-2 has been reported, and a recent study suggested that this was due to cross-recognition of the novel coronavirus by T cells specific for the common cold coronaviruses. METHODS. We used the ELISpot assay to characterize the T cell responses against peptide pools derived from the spike protein of three common cold coronaviruses (HCoV-229E, HCoV-NL63, and HCoV-OC43) and SARS-CoV-2 in 21 healthy donors who were seronegative for SARS-CoV-2 and had no known exposure to the virus. An in vitro expansion culture assay was also used to analyze memory T cell responses. RESULTS. We found responses to the spike protein of the three common cold coronaviruses in many donors. We then focused on HCoV-NL63 and demonstrated broad T cell responses to the spike protein and identified 22 targeted peptides. Interestingly, only one subject had a significant response to SARS-CoV-2 spike or nucleocapsid protein in the ELISpot assay. In vitro expansion studies suggested that T cells specific for the HCoV-NL63 spike protein in this subject could also recognize SARS-CoV-2 spike protein peptide pools. CONCLUSIONS. Healthy donors have circulating T cells specific for the spike proteins of HCoV-NL63, HCoV-229E, and HCoV-OC43. T cell responses to SARS-CoV-2 spike and nucleocapsid proteins were present in only one subject and were potentially the result of cross-recognition by T cells specific for the common cold coronaviruses. Further studies are needed to determine whether this influences COVID-19 outcomes.

Authors

Bezawit A. Woldemeskel, Abena K. Kwaa, Caroline C. Garliss, Oliver Laeyendecker, Stuart C. Ray, Joel N. Blankson

NOTCH-induced rerouting of endosomal trafficking disables regulatory T-cells in vasculitis

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Abstract

The aorta and the large conductive arteries are immunoprivileged tissues and are protected against inflammatory attack. A breakdown of the immunoprivilege leads to autoimmune vasculitis, such as giant cell arteritis (GCA), in which CD8+ T regulatory (Treg) cells fail to contain CD4+ T cells and macrophages, resulting in the formation of tissue-destructive granulomatous lesions. Here, we report that the molecular defect of malfunctioning CD8+ Treg cells lies in aberrant NOTCH4 signaling that deviates endosomal trafficking and minimizes exosome production. By transcriptionally controlling the profile of RAB GTPases, NOTCH4 signaling restricted membrane translocation and vesicular secretion of the enzyme NADPH oxidase 2 (NOX2). Specifically, NOTCH4hiCD8+ Treg cells increased RAB5A and RAB11A expression and suppressed RAB7A, culminating in the accumulation of early and recycling endosomes and trapping of NOX2 in an intracellular, non-secretory compartment. RAB7AloCD8+ Treg cells failed in the surface translocation and the exosomal release of NOX2. NOTCH4hi RAB5Ahi RAB7Alo RAB11Ahi CD8+ Treg cells left adaptive immunity unopposed, enabling a breakdown in tissue tolerance and aggressive vessel wall inflammation. Inhibiting NOTCH4 signaling corrected the defect and protected arteries from inflammatory insult. The study implicates NOTCH4-dependent transcriptional control of RAB proteins and intracellular vesicle trafficking in autoimmune disease and in vascular inflammation.

Authors

Ke Jin, Zhenke Wen, Bowen Wu, Hui Zhang, Jingtao Qiu, Yanan Wang, Kenneth J. Warrington, Gerald Berry, Jörg J. Goronzy, Cornelia M. Weyand