Siska et al. provide evidence for immunometabolic dysregulation in COVID-19, which can be mitigated by dexamethasone treatment. Image credit: Thomas Simeth.
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Vast numbers of differentially expressed genes and perturbed networks have been identified in Alzheimer’s disease (AD), however neither disease- nor brain region-specificity of these transcriptome alterations have been explored. Using RNA sequencing data from 231 temporal cortex and 224 cerebellum samples of patients with AD and progressive supranuclear palsy (PSP), a tauopathy, we identify a striking correlation in the directionality and magnitude of gene expression changes between these two neurodegenerative proteinopathies. Further, the transcriptome changes in AD and PSP are highly conserved between the temporal and cerebellar cortices, indicating highly similar transcriptional changes occur in pathologically affected and grossly less affected, albeit functionally connected, areas of the brain. Shared up- or down-regulated genes in AD and PSP are enriched in biological pathways. Many of these genes also have concordant protein changes and evidence of epigenetic control. These conserved transcriptomic alterations of two distinct proteinopathies in brain regions with and without significant gross neuropathology have broad implications. AD and other neurodegenerative diseases are likely characterized by common disease or compensatory pathways with widespread perturbations in the whole brain. These findings can be leveraged to develop multifaceted therapies and biomarkers that address these common, complex and ubiquitous molecular alterations in neurodegenerative diseases.
Xue Wang, Mariet Allen, Özkan İş, Joseph S. Reddy, Frederick Q. Tutor-New, Monica Castanedes Casey, Minerva M. Carrasquillo, Stephanie R. Oatman, Yuhao Min, Yan W. Asmann, Cory Funk, Thuy Nguyen, Charlotte C.G. Ho, Kimberly G. Malphrus, Nicholas T. Seyfried, Allan I. Levey, Steven G. Younkin, Melissa E. Murray, Dennis W. Dickson, Nathan D. Price, Todd E. Golde, Nilufer Ertekin-Taner
While negative selection of developing B cells in the periphery is well described, yet poorly understood, evidence of naïve B cell positive selection remains elusive. Using two humanized mouse models, we demonstrate that there is strong skewing of expressed immunoglobulin repertoire upon transit into the peripheral naïve B cell pool. This positive selection of expanded naïve B cells in humanized mice resembled that in healthy donors and was independent of autologous thymic tissue. In contrast, negative selection of autoreactive B cells required thymic-derived regulatory T cells (Tregs) and MHC class II-restricted self-antigen presentation by B cells. Indeed, both defective MHC class II expression on their B cells in rare bare lymphocyte syndrome patients or prevention of self-antigen presentation via HLA-DM inhibition in humanized mice result in the production of autoreactive naïve B cells. These latter observations suggest that Tregs repress autoreactive naïve B cells continuously produced by the bone marrow. Thus, a model emerges in which both positive and negative selection shape the human naïve B cell repertoire and that each process is mediated by fundamentally different molecular and cellular mechanisms.
Jeff W. Chen, Jean-Nicolas Schickel, Nikolaos Tsakiris, Joel Sng, Florent Arbogast, Delphine Bouis, Daniele Parisi, Ruchi Gera, Joshua M. Boeckers, Fabien R. Delmotte, Margaret Veselits, Catharina Schuetz, Eva-Maria Jacobsen, Carsten Posovszky, Ansgar S. Schulz, Klaus Schwarz, Marcus R. Clark, Laurence Menard, Eric Meffre
In chronic lymphocytic leukemia (CLL), the B-cell receptor (BCR) plays a critical role in disease development and progression as indicated by the therapeutic efficacy of drugs blocking BCR signaling. However, the mechanism(s) underlining BCR responsiveness are not completely defined. Selective engagement of membrane IgM or IgD on CLL cells, each co-expressed by > 90% of cases, leads to distinct signaling events. Since both IgM and IgD carry the same antigen-binding domains, the divergent actions of the receptors are attributed to differences in immunoglobulin (IG) structure or the outcome of signal transduction. We showed that IgM, not IgD, level and organization linked with CLL-cell birth rate and the type and consequences of BCR signaling in humans and mice. The latter IgM-driven effects were abrogated when BCR signaling was inhibited. Collectively, these studies demonstrated a critical, selective role for IgM in BCR signaling and B-cell fate decisions, possibly opening new avenues for CLL therapy.
Andrea N. Mazzarello, Eva Gentner-Göbel, Marcus Dühren-von Minden, Tatyana N. Tarasenko, Antonella Nicolò, Gerardo Ferrer, Stefano Vergani, Yun Liu, Davide Bagnara, Kanti R. Rai, Jan A. Burger, Peter J. McGuire, Palash C. Maity, Hassan Jumaa, Nicholas Chiorazzi
Various population of cells are recruited to the heart after cardiac injury but little is known about whether the cardiomyocyte directly regulates heart repair. In a murine model of ischemic cardiac injury, we demonstrate that the cardiomyocyte plays a pivotal role in heart repair by regulating nucleotide metabolism and fates of non-myocytes. Cardiac injury induced the expression of the ectonucleotidase ENPP1 that hydrolyzes extracellular ATP to form AMP. In response to AMP, the cardiomyocyte released adenine and specific ribonucleosides that disrupted pyrimidine biosynthesis at OMP synthesis step, induced genotoxic stress and a p53 mediated cell death of cycling non-myocytes. As non-myocytes are critical for heart repair, we showed that rescue of pyrimidine biosynthesis by administration of uridine or by genetic targeting of ENPP1/AMP pathway enhanced repair after cardiac injury. We identified ENPP1 inhibitors on small molecule screening and showed that systemic administration of an ENPP1 inhibitor after heart injury rescued pyrimidine biosynthesis in non-myocyte cells, augmented cardiac repair and post infarct heart function. These observations demonstrate that the cardiac muscle cell by releasing adenine and specific nucleosides after heart injury regulates pyrimidine metabolism in non-muscle cells and provide insight into how inter-cellular regulation of pyrimidine biosynthesis can be targeted and monitored for augmenting tissue repair.
Shen Li, Tomohiro Yokota, Ping Wang, Johanna ten Hoeve, Feiyang Ma, Thuc M. Le, Evan R. Abt, Yonggang Zhou, Rimao Wu, Maxine Nanthavongdouangsy, Abraham Rodriguez, Yijie Wang, Yen-Ju Lin, Hayato Muranaka, Mark Sharpley, Demetrios T. Braddock, Vicky E. MacRae, Utpal Banerjee, Pei-Yu Chiou, Marcus Seldin, Dian Huang, Michael Teitell, Ilya Gertsman, Michael Jung, Steven J. Bensinger, Robert Damoiseaux, Kym Faull, Matteo Pellegrini, Aldons Lusis, Thomas G. Graeber, Caius G. Radu, Arjun Deb
BACKGROUND. Neoantigen-driven recognition and T cell-mediated killing contribute to tumor clearance following adoptive cell therapy (ACT) with Tumor-Infiltrating Lymphocytes (TILs). Yet, how diversity, frequency, and persistence of expanded neoepitope-specific CD8+ T cells derived from TIL infusion products affect patient outcome is not fully determined. METHODS. Using barcoded pMHC multimers, we provide a comprehensive mapping of CD8+ T cells recognizing neoepitopes in TIL infusion products and blood samples from 26 metastatic mela-noma patients who received ACT. RESULTS. We identified 106 neoepitopes within TIL infusion products corresponding to 1.8% of all predicted neoepitopes. We observed neoepitope-specific recognition to be virtually devoid in TIL infusion products given to patients with progressive disease outcome. Moreover, we found that the frequency of neoepitope-specific CD8+ T cells in TIL infusion products correlated with in-creased survival, and that detection of engrafted CD8+ T cells in post-treatment (i.e. originating from the TIL infusion product) were unique to responders of TIL-ACT. Finally, we found that a transcriptional signature for lymphocyte activity within the tumor microenvironment was associated with a higher frequency of neoepitope-specific CD8+ T cells in the infusion product. CONCLUSIONS. These data support previous case studies of neoepitope-specific CD8+ T cells in melanoma, and indicate that successful TIL-ACT is associated with an expansion of neoepitope-specific CD8+ T cells. FUNDING. NEYE Foundation; European Research Council; Lundbeck Foundation Fellowship; Carlsberg Foundation.
Nikolaj Pagh Kristensen, Christina Heeke, Siri A. Tvingsholm, Annie Borch, Arianna Draghi, Michael D. Crowther, Ibel Carri, Kamilla K. Munk, Jeppe Sejerø Holm, Anne-Mette Bjerregaard, Amalie Kai Bentzen, Andrea M. Marquard, Zoltan Szallasi, Nicholas McGranahan, Rikke Andersen, Morten Nielsen, Göran B. Jönsson, Marco Donia, Inge Marie Svane, Sine Reker Hadrup
JCI This Month is a digest of the research, reviews, and other features published each month.
Animals, plants, and bacteria all display behavioral patterns that coincide with Earth’s light and dark cycles. These oscillating behaviors are the manifestation of the molecular circadian clock, a highly conserved network that maintains a near 24-hour rhythm even in the absence of light. In mammals, light signals are transmitted via the superchiasmatic nucleus (SCN) in the hypothalamus to synchronize peripheral clocks and coordinate physiological functions with the organism’s active period. This collection of reviews, curated by Amita Sehgal, considers the critical role of the circadian system in human health. Technology, work, and social obligations can disrupt optimal sleep and wake schedules, leaving humans vulnerable to diseases affecting the heart, brain, metabolism, and more. Sleep disorders as well as normal variations in human chronotype may exacerbate circadian disruptions, with profound consequences. These reviews emphasize that ongoing efforts to understand the complexities of human circadian rhythm will be essential for developing chronotherapies and other circadian-based interventions.