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Boosting NAD Level Suppresses Inflammatory Activation of PBMC in Heart Failure

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Abstract

Background:While mitochondria play an important role in innate immunity, the relationship between mitochondrial dysfunction and inflammation in heart failure (HF) is poorly understood. In this study we aimed to investigate the mechanistic link between mitochondrial dysfunction and inflammatory activation in peripheral blood mononuclear cells (PBMCs), and the potential anti-inflammatory effect of boosting NAD level.Methods:We compared the PBMC mitochondrial respiration of 19 hospitalized Stage D HF patients with 19 healthy participants. We then created an in vitro model of sterile inflammation by treating healthy PBMC with MitoDAMP (Mitochondrial Damage-Associated Molecular Patterns) isolated from human heart tissue. Lastly, we enrolled Stage D HF patients and sampled their blood before and after taking 5-9 days of oral nicotinamide riboside, an NAD precursor.Results:We demonstrated that HF is associated with both reduced respiratory capacity and elevated proinflammatory cytokine gene expressions. In our in vitro model, MitoDAMP-treated PBMCs secreted IL-6 that impaired mitochondrial respiration by reducing Complex I activity. Last, oral NR administration enhanced PBMC respiration and reduced proinflammatory cytokine gene expression in 4 HF subjects.Conclusion:These findings suggest that systemic inflammation in HF patients is causally linked to mitochondrial function of the PBMC. Increasing NAD levels may have the potential to improve mitochondrial respiration and attenuate proinflammatory activation of PBMC in HF. FundingThis study is funded by NIH R21 HL126209 (to RT and KO), NIH R01 HL144937 (to KO and RT) and University of Washington ITHS Catalyst Award (to DDW). Both BZ (18POST33990352) and DDW (18POST34030098) are funded by the AHA Postdoctoral Fellowships.

Authors

Bo Zhou, Dennis D. Wang, Yanhua Qiu, Sophia Airhart, Yaxin Liu, April Stempien-Otero, Kevin D. O’Brien, Rong Tian.

Mef2d sustains activation of effector Foxp3+ Tregs during transplant survival and anticancer immunity

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The transcription factor, Mef2d, is important in the regulation of differentiation and adaptive responses in many cell types. Among T cells, Mef2d gains new functions in Foxp3+ T-regulatory (Treg) cells as a result of its interactions with the transcription factor, Foxp3, and its release from canonical partners, like histone/protein deacetylases. Though not necessary for the generation and maintenance of Tregs, Mef2d is required for the expression of IL-10, Ctla-4 and Icos, and for the acquisition of an effector Treg phenotype. At these loci, Mef2d acts both synergistically and additively to Foxp3, and down-stream of Blimp1. Mice with the conditional deletion in Tregs of the gene encoding Mef2d are unable to maintain long-term allograft survival despite costimulation blockade and have enhanced antitumor immunity in syngeneic models, but they display only minor evidence of autoimmunity when maintained under normal conditions. The role played by Mef2d in sustaining effector Foxp3+ Treg functions without abrogating their basal actions suggests its suitability for drug discovery efforts in cancer therapy.

Authors

Eros Di Giorgio, Liqing Wang, Yan Xiong, Tatiana Akimova, Lanette M. Christensen, Rongxiang Han, Arabinda Samanta, Matteo Trevisanut, Tricia R. Bhatti, Ulf H. Beier, Wayne W. Hancock

Truncated stathmin-2 is a marker of TDP-43 pathology in frontotemporal dementia

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No treatment for frontotemporal dementia (FTD), the second most common early-onset dementia, is available but therapeutics are being investigated to target the two main proteins associated with FTD pathological subtypes: TDP-43 (FTLD-TDP) and tau (FTLD-tau). Testing potential therapies in clinical trials is hamstrung by our inability to distinguish between patients with FTLD-TDP and FTLD-tau. Therefore, we evaluated truncated stathmin-2 (STMN2) as a proxy of TDP-43 pathology, given reports that TDP-43 dysfunction causes truncated STMN2 accumulation. Truncated STMN2 accumulated in human iPSC-derived neurons depleted of TDP-43, but not in those with pathogenic TARDBP mutations in the absence of TDP-43 aggregation or loss of nuclear protein. In RNA-seq analyses of human brain samples from the NYGC ALS cohort, truncated STMN2 RNA was confined to tissues and disease sub-types marked by TDP-43 inclusions. Lastly, we validated that truncated STMN2 RNA is elevated in the frontal cortex of a cohort of FTLD-TDP cases but not in controls or cases with progressive supranuclear palsy (PSP), a type of FTLD-tau. Further, in FTLD-TDP, we observed significant associations of truncated STMN2 RNA with phosphorylated TDP-43 levels and an earlier age of disease onset. Overall, our data uncovered truncated STMN2 as a marker for TDP-43 dysfunction in FTD.

Authors

Mercedes Prudencio, Jack Humphrey, Sarah Pickles, Anna-Leigh Brown, Sarah E. Hill, Jennifer Kachergus, Ji Shi, Michael Heckman, Matthew Spiegel, Casey Cook, Yuping Song, Mei Yue, Lillian Daughrity, Yari Carlomagno, Karen Jansen-West, Cristhoper Fernandez De Castro, Michael DeTure, Shunsuke Koga, Ying-Chih Wang, Prasanth Sivakumar, Cristian Bodo, Ana Candalija, Kevin Talbot, Bhuvaneish T. Selvaraj, Karen Burr, Siddharthan Chandran, Jia Newcombe, Tammaryn Lashley, Isabel Hubbard, Demetra Catalano, Duyang Kim, Nadia Propp, Samantha Fennessey, Delphine Fagegaltier, Hemali Phatnani, Maria Secrier, Elizabeth M.C. Fisher, Björn Oskarsson, Marka van Blitterswijk, Rosa Rademakers, Neill R. Graff-Radford, Bradley Boeve, David S. Knopman, Ronald Petersen, Keith Josephs, E. Aubrey Thompson, Towfique Raj, Michael E. Ward, Dennis Dickson, Tania F. Gendron, Pietro Fratta, Leonard Petrucelli

Mutations affecting the conserved acidic WNK1 motif cause inherited hyperkalemic hyperchloremic acidosis

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Gain-of-function mutations in the WNK1 and WNK4 genes are responsible for Familial Hyperkalemic Hypertension (FHHt), a rare inherited disorder characterized by arterial hypertension and hyperkalemia with metabolic acidosis. More recently, FHHt-causing mutations in the KLHL3-CUL3 E3 ubiquitin ligase complex have shed light on the importance of WNKs cellular degradation on renal ion transport. Using full exome sequencing in a four-generation family and then targeted sequencing in other suspected cases, we have identified new missense variants at the WNK1 gene, clustering in the short conserved acidic motif known to interact with the KLHL3-CUL3 ubiquitin complex. Affected subjects had an early-onset and a marked hyperkalemic phenotype, but normal blood pressure values. Functional experiments in Xenopus laevis oocytes and HEK293T cells demonstrated that these mutations strongly decrease the ubiquitination of the kidney-specific isoform KS-WNK1 by the KLHL3-CUL3 complex, rather than the long ubiquitous catalytically active L-WNK1 isoform. A corresponding CRISPR-Cas9 engineered mouse model recapitulated both the clinical and biological phenotype. Renal investigations showed increased activation of the SPAK-NCC phosphorylation cascade, associated with impaired ROMK apical expression in the distal part of the renal tubule. Altogether, these new WNK1 genetic variants highlight the importance of the KS-WNK1 isoform abundance on potassium homeostasis.

Authors

Helene Louis-Dit-Picard, Ilektra Kouranti, Chloe Rafael, Irmine Loisel-Ferreira, Maria Chavez-Canales, Waed Abdel Khalek, Eduardo Argaiz, Stephanie Baron, Sarah Vacle, Tiffany Migeon, Richard Coleman, Marcio Do Cruzeiro, Marguerite Hureaux, Nirubiah Thurairajasingam, Stéphane Decramer, Xavier Girerd, Kevin M. O'Shaughnessy, Paolo Mulatero, Gwenaelle Roussey, Ivan Tack, Robert J. Unwin, Rosa Vargas-Poussou, Olivier Staub, P. Richard Grimm, Paul A. Welling, Gerardo Gamba, Eric Clauser, Juliette Hadchouel, Xavier Jeunemaitre

COVID-19 severity associates with pulmonary redistribution of CD1c⁺ DC and inflammatory transitional and nonclassical monocytes

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SARS-CoV-2 is responsible for development of COVID-19 in infected individuals, who can either exhibit mild symptoms or progress towards a life-threatening acute respiratory distress syndrome (ARDS). Exacerbated inflammation and dysregulated immune responses involving T and myeloid cells occur in COVID-19 patients with severe clinical progression. However, the differential contribution of specific subsets of dendritic cells and monocytes to ARDS is still poorly understood. In addition, the role of CD8+ T cells present in the lung of COVID-19 patients and relevant for viral control has not been characterized. Here, we have studied the frequencies and activation profiles of dendritic cells and monocytes present in the blood and lung of COVID-19 patients with different clinical severity in comparison with healthy individuals. Furthermore, these subpopulations and their association with antiviral effector CD8+ T cell subsets were also characterized in lung infiltrates from critical COVID-19 patients. Our results indicate that inflammatory transitional and non-classical monocytes and CD1c+ conventional dendritic cells preferentially migrate from blood to lungs in patients with severe COVID-19. Thus, this study increases the knowledge on specific myeloid subsets involved in the pathogenesis of COVID-19 disease and could be useful for the design of therapeutic strategies to fight SARS-CoV-2 infection.

Authors

Ildefonso Sánchez-Cerrillo, Pedro Landete, Beatriz Aldave, Santiago Sánchez-Alonso, Ana Sánchez-Azofra, Ana Marcos-Jiménez, Elena Ávalos, Ana Alcaraz-Serna, Ignacio de los Santos, Tamara Mateu-Albero, Laura Esparcia, Celia López-Sanz, Pedro Martínez-Fleta, Ligia Gabrie, Luciana del Campo Guerola, Hortensia de la Fuente, María J Calzada, Isidoro González-Álvaro, Arantzazu Alfranca, Francisco Sánchez-Madrid, Cecilia Muñoz-Calleja, Joan B. Soriano, Julio Ancochea, Enrique Martín-Gayo

Autologous CMV‐specific T cells are a safe adjuvant immunotherapy for primary glioblastoma multiforme

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Background: The recent failure of checkpoint-blockade therapies for glioblastoma multiforme (GBM) in late-phase clinical trials has directed interest towards adoptive cellular immunotherapies (ACT). In this open-label, first-in-human trial, we have assessed the safety and therapeutic potential of cytomegalovirus (CMV)-specific ACT in an adjuvant setting for patients with primary GBM, with an ultimate goal to prevent or delay recurrence and prolong overall survival. Methods: Twenty-eight patients with primary GBM were recruited to this prospective study, 25 of whom were treated with in vitro-expanded autologous CMV-specific T cells. Participants were monitored for safety, progression-free survival (PFS), overall survival (OS) and immune reconstitution. Results: No participants showed evidence of ACT-related toxicities. Of 25 evaluable participants, ten were alive at the completion of follow-up, while five were disease free. Reconstitution of CMV-specific T-cell immunity was evident and CMV-specific ACT may trigger bystander effect leading to additional T-cell responses to non-viral tumour-associated antigens through epitope spreading. Long-term follow-up of participants treated before recurrence showed significantly improved OS when compared to those who progressed before ACT (median 23 months, range 7–65 vs. median 14 months, range 5–19; p=0.018). Gene expression analysis of the ACT products indicated that a favourable T-cell gene signature was associated with improved long-term survival. Conclusion: Data presented in this study demonstrate that CMV-specific ACT can be safely used as an adjuvant therapy for primary GBM and, if offered before recurrence, this therapy may improve overall survival of GBM patients.Trial registration: anzctr.org.au: ACTRN12615000656538Funding Source:National Health & Medical Research Council (Australia) Trial registration: anzctr.org.au: ACTRN12615000656538 Funding Source: Philanthropic funding &National Health & Medical Research Council (Australia)

Authors

Corey Smith, Katie E. Lineburg, J. Paulo Martins, George Ambalathingal, Michelle A. Neller, Beth Morrison, Katherine K. Matthews, Sweera Rehan, Pauline Crooks, Archana Panikkar, Leone Beagley, Laetitia Le Texier, Sriganesh Srihari, David Walker, Rajiv Khanna

Metabolic effects of air pollution exposure and reversibility

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Particulate matter < 2.5 micrometers (PM2.5) air pollution is the world’s leading environmental risk factor contributing to mortality through cardiometabolic pathways. In this study, we modeled early life exposure using chow-fed C57BL/6J male mice, exposed to real-world inhaled concentrated PM2.5 (~10 times ambient levels / ~60-120ug/m3) or filtered air over 14 weeks. We investigated PM2.5 effects on phenotype, transcriptome and chromatin accessibility, compared the effects with a prototypical high-fat diet (HFD) stimulus, and examined cessation of exposure on reversibility of phenotype. Exposure to PM2.5 impaired glucose and insulin tolerance, reduced energy expenditure and 18FDG-PET uptake in brown adipose tissue. Multiple differentially expressed gene (DEG) clusters in pathways involving metabolism and circadian rhythm were noted in insulin responsive tissues. Although the magnitude of transcriptional change seen with PM2.5 was lower than HFD, the degree of alteration in chromatin accessibility after PM2.5 exposure was significant. A novel chromatin remodeler SMARCA5 (SWI/SNF complex) was regulated in response to PM2.5 with cessation of exposure associated with reversal of insulin resistance, restoration of chromatin accessibility/nucleosome positioning near transcription start sites (TSS) and exposure induced changes in the transcriptome including SMARCA5, indicating pliable epigenetic control mechanisms following exposure cessation.

Authors

Sanjay Rajagopalan, Bongsoo Park, Rengasamy Palanivel, Vinesh Vinayachandran, Jeffrey A. Deiuliis, Roopesh Singh Gangwar, Lopa M. Das, Jinhu Yin, Youngshim Choi, Sadeer Al-Kindi, Mukesh K. Jain, Kasper D. Hansen, Shyam Biswal

Sleeping Beauty-engineered CAR T cells achieve anti-leukemic activity without severe toxicities

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Background. Chimeric antigen receptor (CAR) T cell immunotherapy has achieved complete remission and durable response in highly refractory patients. However, logistical complexity and high costs of manufacturing autologous viral products limit CAR T cell availability. Methods. We reported the early results of a phase I/II trial in B-cell acute lymphoblastic leukemia (B-ALL) patients relapsed after allogeneic hematopoietic stem cell transplantation (HSCT) using donor-derived CD19 CAR T cells generated with the Sleeping Beauty (SB) transposon and differentiated into cytokine induced killer cells (CIK). Results. The cellular product was produced successfully for all patients from the donor peripheral blood (PB) and consisted mostly of CD3+ lymphocytes with 43% CAR expression. Four pediatric and 9 adult patients were infused with a single dose of CAR T cells. Toxicities reported were two grade I and a grade II cytokine release syndrome (CRS) cases at the highest dose, in the absence of graft-versus-host disease (GvHD), neurotoxicity, or dose-limiting toxicities. Six out of 7 patients, receiving the highest doses, achieved CR and CRi at day 28. Five out of 6 patients in CR were also minimal residual disease (MRD)-negative. Robust expansion was achieved in the majority of the patients. CAR T cells were measurable by transgene copy PCR up to 10 months. Integration site analysis showed a positive safety profile and highly polyclonal repertoire in vitro and at early time points after infusion. Conclusion. SB-engineered CAR T cells expand and persist in pediatric and adult B-ALL patients relapsed after HSCT. Anti-leukemic activity was achieved without severe toxicities. Trial registration. clinicaltrials.gov NCT03389035.Funding. This study was supported by grants from AIRC; CRUK; FC AECC; Ministero della salute; FRRB.

Authors

Chiara F. Magnani, Giuseppe Gaipa, Federico Lussana, Daniela Belotti, Giuseppe Gritti, Sara Napolitano, Giada Matera, Benedetta Cabiati, Chiara Buracchi, Gianmaria Borleri, Grazia Fazio, Silvia Zaninelli, Sarah Tettamanti, Stefania Cesana, Valentina Colombo, Michele Quaroni, Giovanni Cazzaniga, Attilio Rovelli, Ettore Biagi, Stefania Galimberti, Andrea Calabria, Fabrizio Benedicenti, Eugenio Montini, Silvia Ferrari, Martino Introna, Adriana Balduzzi, Maria Grazia Valsecchi, Giuseppe Dastoli, Alessandro Rambaldi, Andrea Biondi

Type 2 diabetes risk gene Dusp8 regulates hypothalamic Jnk signaling and insulin sensitivity

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Recent genome-wide association studies (GWAS) identified DUSP8, a dual-specificity phosphatase targeting MAP kinases, as type 2 diabetes (T2D) risk gene. Here, we unravel Dusp8 as gatekeeper in the hypothalamic control of glucose homeostasis in mice and humans. Male but not female Dusp8 loss-of-function mice, either with global or CRH neuron-specific deletion, had impaired systemic glucose tolerance and insulin sensitivity when exposed to high-fat diet (HFD). Mechanistically, we found impaired hypothalamic–pituitary–adrenal (HPA) axis feedback, blunted sympathetic responsiveness, and chronically elevated corticosterone levels driven by hypothalamic hyperactivation of Jnk signaling. Accordingly, global Jnk1 ablation, AAV-mediated Dusp8 overexpression in the mediobasal hypothalamus, or metyrapone-induced chemical adrenalectomy rescued the impaired glucose homeostasis of obese male Dusp8 KO mice, respectively. The sex-specific role of murine Dusp8 in governing hypothalamic Jnk signaling, insulin sensitivity and systemic glucose tolerance was consistent with fMRI data in human volunteers that revealed an association of the DUSP8 rs2334499 risk variant with hypothalamic insulin resistance in men. Further, expression of DUSP8 was increased in the infundibular nucleus of T2D humans. In summary, our findings suggest the GWAS-identified gene Dusp8 as novel hypothalamic factor that plays a functional role in the etiology of T2D.

Authors

Sonja C. Schriever, Dhiraj G. Kabra, Katrin Pfuhlmann, Peter Baumann, Emily V. Baumgart, Joachim Nagler, Fabian Seebacher, Luke Harrison, Martin Irmler, Stephanie Kullmann, Felipe Corrêa-da-Silva, Florian Giesert, Ruchi Jain, Hannah Schug, Julien Castel, Sarah Martinez, Moya Wu, Hans-Ulrich Häring, Martin Hrabe de Angelis, Johannes Beckers, Timo D. Müller, Kerstin Stemmer, Wolfgang Wurst, Jan Rozman, Rubén Nogueiras, Meri De Angelis, Jeffery D. Molkentin, Natalie Krahmer, Chun-Xia Yi, Mathias V. Schmidt, Serge Luquet, Martin Heni, Matthias H. Tschoep, Paul T. Pfluger

Sex, age, and hospitalization drive antibody responses in a COVID-19 convalescent plasma donor population

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Convalescent plasma is a leading treatment for COVID-19, but there is a paucity of data identifying therapeutic efficacy. Among 126 potential convalescent plasma donors, the humoral immune response was evaluated by a SARS-CoV-2 virus neutralization assay using Vero-E6-TMPRSS2 cells, commercial IgG and IgA ELISA to spike(S) protein S1 domain (Euroimmun), IgA, IgG and IgM indirect ELISAs to the full-length S or S-receptor binding domain(S-RBD), and an IgG avidity assay. Multiple linear regression and predictive models were utilized to assess the correlations between antibody responses with demographic and clinical characteristics. IgG titers were greater than either IgM or IgA for S1, full length S, and S-RBD in the overall population. Of the 126 plasma samples, 101(80%) had detectable neutralizing antibody(nAb) titers. Using nAb titers as the reference, the IgG ELISAs confirmed between 95-98% of the nAb positive, but only 20-32% of the nAb negative samples. Male sex, older age, and hospitalization with COVID-19 were associated with increased antibody responses across the serological assays. There was substantial heterogeneity in the antibody response among potential convalescent plasma donors, but sex, age, and hospitalization emerged as factors that can be used to identify individuals with a high likelihood of having strong antiviral antibody responses.

Authors

Sabra L. Klein, Andrew Pekosz, Han-Sol Park, Rebecca L. Ursin, Janna R. Shapiro, Sarah E. Benner, Kirsten Littlefield, Swetha Kumar, Harnish Mukesh Naik, Michael Betenbaugh, Ruchee Shrestha, Annie A. Wu, Robert M. Hughes, Imani Burgess, Patrizio Caturegli, Oliver Laeyendecker, Thomas C. Quinn, David J. Sullivan, Shmuel Shoham, Andrew D. Redd, Evan M. Bloch, Arturo Casadevall, Aaron A. R. Tobian

Complement and tissue factor-enriched neutrophil extracellular traps are key drivers in COVID-19 immunothrombosis

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Emerging data indicate that complement and neutrophils contribute to the maladaptive immune response that fuels hyper-inflammation and thrombotic microangiopathy, thereby increasing COVID-19 mortality. Here, we investigated how complement interacts with the platelet/neutrophil extracellular traps (NETs)/thrombin axis, using COVID-19 specimens, cell-based inhibition studies and NETs/human aortic endothelial cell (HAEC) co-cultures. Increased plasma levels of NETs, tissue factor (TF) activity and sC5b-9 were detected in patients. Neutrophils of patients yielded high TF expression and released NETs carrying active TF. Treatment of control neutrophils with COVID-19 platelet-rich plasma generated TF-bearing NETs that induced thrombotic activity of HAEC. Thrombin or NETosis inhibition or C5aR1 blockade attenuated platelet-mediated NET-driven thrombogenicity. COVID-19 serum induced complement activation in vitro, consistent with high complement activity in clinical samples. Complement C3 inhibition with compstatin Cp40 disrupted TF expression in neutrophils. In conclusion, we provide a mechanistic basis for a pivotal role of complement and NETs in COVID-19 immunothrombosis. This study supports strategies against SARS-CoV-2 that exploit complement or NETosis inhibition.

Authors

Panagiotis Skendros, Alexandros Mitsios, Akrivi Chrysanthopoulou, Dimitrios C. Mastellos, Simeon Metallidis, Petros Rafailidis, Maria Ntinopoulou, Eleni Sertaridou, Victoria Tsironidou, Christina Tsigalou, Maria G. Tektonidou, Theocharis Konstantinidis, Charalampos Papagoras, Ioannis Mitroulis, Georgios Germanidis, John D. Lambris, Konstantinos Ritis

Inhibition of mitophagy drives macrophage activation and anti-bacterial defense during sepsis

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Mitochondria have emerged as key actors of innate and adaptive immunity. Mitophagy has a pivotal role in cell homeostasis but its contribution to macrophage functions and host defense remains to be delineated. Here we showed that lipopolysaccharide (LPS) in combination with IFNγ, inhibits PINK1-dependent mitophagy in macrophages through a STAT1-dependent activation of the inflammatory caspases 1 and 11. In addition, we demonstrated that the inhibition of mitophagy triggers classical macrophage activation in a mitochondrial ROS-dependent manner. In a murine model of polymicrobial infection (cecal ligature and puncture, CLP), adoptive transfer of Pink1-deficient bone marrow or pharmacological inhibition of mitophagy promoted macrophage activation which favored bactericidal clearance and lead to a better survival. Reciprocally, mitochondrial uncouplers, that promote mitophagy, reverse LPS/IFNγ-mediated activation of macrophages and lead to immuno-paralysis with impaired bacterial clearance and lowered survival. In critically ill patients, we showed that mitophagy is inhibited in blood monocytes of patients with sepsis as compared to non-septic patients. Overall, this work demonstrates that the inhibition of mitophagy is a physiological mechanism that contributes to the activation of myeloid cells and improves the outcome of sepsis.

Authors

Danish Patoli, Franck Mignotte, Valérie Deckert, Alois Dusuel, Adelie Dumont, Aurelie Rieu, Antoine Jalil, Kevin Van Dongen, Thibaut Bourgeois, Thomas Gautier, Charlene Magnani, Naig Le Guern, Stéphane Mandard, Jean Bastin, Fatima Djouadi, Christine Schaeffer, Nina Guillaumot, Michel Narce, Maxime Nguyen, Julien Guy, Auguste Dargent, Jean-Pierre Quenot, Mickaël Rialland, David Masson, Johan Auwerx, Laurent Lagrost, Charles Thomas

Hypoxia-inducible factors and innate immunity in liver cancer

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The liver has strong innate immunity to counteract pathogens from the gastrointestinal tract. During the development of liver cancer, which is typically driven by chronic inflammation, the composition and biological roles of the innate immune cells are extensively altered. Hypoxia is a common finding in all stages of liver cancer development. Hypoxia drives the stabilization of hypoxia-inducible factors (HIFs), which act as central regulators to dampen the innate immunity of liver cancer. HIF signaling in innate immune cells and liver cancer cells together favor the recruitment and maintenance of pro-tumorigenic immune cells and the inhibition of anti-tumorigenic immune cells, promoting immune evasion. HIFs represent attractive therapeutic targets to inhibit the formation of an immunosuppressive microenvironment and growth of liver cancer.

Authors

Vincent Wai-Hin Yuen, Carmen Chak-Lui Wong

Dominant-negative NFKBIA mutation promotes IL-1β production causing hepatic disease with severe immunodeficiency

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Although IKK-β has previously been shown as a negative regulator of IL-1β secretion in mice, this role has not been demonstrated in humans. Genetic studies of NF-κB signalling in humans with inherited diseases of the immune system have not demonstrated the relevance of the NF-κB pathway in suppression of IL-1β expression. Here, we report an infant displaying clinical pathology comprising neutrophil-mediated auto-inflammation and recurrent bacterial infections. Whole-exome sequencing revealed a de novo heterozygous missense mutation in NFKBIA, resulting in a L34P IκBα variant, that severely repressed NF-κB activation and downstream cytokine production. Paradoxically, IL-1β secretion was elevated in the patient’s stimulated leukocytes, in her induced-pluripotent stem cell-derived macrophages, and in murine bone marrow-derived macrophages containing the L34P mutation. The patient’s hyper-IL-1β secretion correlated with activated neutrophilia and liver fibrosis with neutrophil accumulation. Hematopoietic stem cell transplantation reversed neutrophilia, restored a resting state in neutrophils, and normalized IL-1β release from stimulated leukocytes. Additional therapeutic blockade of IL-1 ameliorated liver damage, whilst decreasing neutrophil activation and associated IL-1β secretion. Our studies reveal a previously unrecognized role of human IκBα as an essential regulator of canonical NF-κB signalling in the prevention of neutrophilic-dependent auto-inflammatory diseases. We showed that IκBα controls IL-1β secretion through a mechanism of self-limiting post-transcriptional regulation. These findings also highlight a therapeutic potential for IL-1 inhibitors to treat complications arising from systemic NF-κB inhibition.

Authors

Enrica Ee Kar Tan, Richard Hopkins, Chrissie K. Lim, Saumya Jamuar, Christina Ong, Koh Cheng Thoon, Mark J.A. Koh, Eun Myoung Shin, Derrick Wen Quan Lian, Madhushanee Weerasooriya, Christopher Z.W Lee, Andreas Alvin Purnomo Soetedjo, Chang Siang Lim, Veronica B. Au, WM Edmond Chua, Hui Yin Lee, Leigh Ann Jones, Sharmy Jennifer James, Nivashini Kaliaperumal, Jeffrey Kwok, Ee Shien Tan, Biju Thomas, Lena Ho, Lynn Wu, Anna-Marie Fairhurst, Florent Ginhoux, Adrian K.K. Teo, Yongliang Zhang, Kok Haur Ong, Weimiao Yu, Byrappa Venkatesh, Vinay Tergaonkar, Bruno Reversade, Keh-Chuang Chin, Ah Moy Tan, Woei Kang Liew, John E. Connolly

Protein phosphatase 2A B55ß limits CD8 T cell lifespan following cytokine withdrawal

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How T cells integrate environmental cues into signals that limit the magnitude and length of immune responses is poorly understood. Here, we provide data that demonstrates that B55ß, a regulatory subunit of the phosphatase PP2A, represents a molecular link between cytokine concentration and apoptosis in activated CD8 T cells. Through the modulation of AKT, B55ß induced the expression of the pro-apoptotic molecule Hrk in response to cytokine withdrawal. Accordingly, B55ß and Hrk were both required for in vivo and in vitro contraction of activated CD8 lymphocytes. We show that this process plays a role during clonal contraction, establishment of immune memory, and preservation of peripheral tolerance. This regulatory pathway may represent an unexplored opportunity to end unwanted immune responses, or to promote immune memory.

Authors

Noé Rodríguez-Rodríguez, Iris K. Madera-Salcedo, J. Alejandro Cisneros-Segura, H. Benjamin García-González, Sokratis A. Apostolidis, Abril Saint-Martin, Marcela Esquivel-Velázquez, Tran Nguyen, Dámaris P. Romero-Rodríguez, George C. Tsokos, Jorge Alcocer-Varela, Florencia Rosetti, Jose C. Crispin

BIN2 orchestrates platelet calcium signaling in thrombosis and thrombo-inflammation

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Store-operated calcium entry (SOCE) is the major route of Ca2+ influx in platelets. The Ca2+ sensor stromal interaction molecule 1 (STIM1) triggers SOCE by forming puncta structures with the Ca2+ channel Orai1 and the inositol trisphosphate receptor (IP3R), thereby linking the endo-/sarcoplasmic reticulum to the plasma membrane. Here, we identified the BAR domain superfamily member bridging integrator 2 (BIN2) as an interaction partner of STIM1 and IP3R in platelets. Deletion of platelet Bin2 (Bin2fl/fl,Pf4-Cre mice) resulted in reduced Ca2+ store release and Ca2+ influx in response to all tested platelet agonists. These defects were a consequence of impaired IP3R function in combination with defective STIM1-mediated SOC channel activation, while Ca2+ store content and agonist-induced IP3 production were unaltered. These defects translated into impaired thrombus formation under flow and a protection of Bin2fl/fl,Pf4-Cre mice in models of arterial thrombosis and stroke. These results establish BIN2 as a central regulator of platelet activation in thrombosis and thrombo-inflammatory disease settings.

Authors

Julia Volz, Charly Kusch, Sarah Beck, Michael Popp, Timo Vögtle, Mara Meub, Inga Scheller, Hannah S. Heil, Julia Preu, Michael K. Schuhmann, Katherina Hemmen, Thomas Premsler, Albert Sickmann, Katrin G. Heinze, David Stegner, Guido Stoll, Attila Braun, Markus Sauer, Bernhard Nieswandt

COVID-19, racism, and the pursuit of health care and research worthy of trust

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This Viewpoint describes how physicians and researchers can utilize approaches based on relationship-centered care and structural competence to reduce racism and enhance trustworthiness in health care and biomedical research.

Authors

Lisa A. Cooper, Deidra C. Crews

Complement activation on endothelium initiates antibody-mediated acute lung injury

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Antibodies targeting human leukocyte antigen (HLA)/major histocompatibility complex (MHC) proteins limit successful transplantation and transfusion, and their presence in blood products can cause lethal transfusion-related acute lung injury (TRALI). It is unclear which cell types are bound by these ‘anti-leukocyte’ antibodies to initiate an immunologic cascade resulting in lung injury. We therefore conditionally removed MHC class I (MHC I) from likely cellular targets in antibody-mediated lung injury. Only the removal of endothelial MHC I reduced lung injury and mortality, related mechanistically to absent endothelial complement fixation and lung platelet retention. Restoration of endothelial MHC I rendered MHC I-deficient mice susceptible to lung injury. Neutrophil responses, including neutrophil extracellular trap (NET) release, were intact in endothelial MHC I-deficient mice, whereas complement depletion reduced both lung injury and NETs. Human pulmonary endothelial cells showed high HLA class I expression, and post-transfusion complement activation was increased in clinical TRALI. These results indicate that the critical source of antigen for ‘anti-leukocyte’ antibodies is in fact the endothelium, which reframes our understanding of TRALI as a rapid-onset vasculitis. Inhibition of complement activation may have multiple beneficial effects of reducing endothelial injury, platelet retention, and NET release in conditions where antibodies trigger these pathogenic responses.

Authors

Simon J. Cleary, Nicholas Kwaan, Jennifer J. Tian, Daniel R. Calabrese, Beñat Mallavia, Mélia Magnen, John R. Greenland, Anatoly Urisman, Jonathan P. Singer, Steven R. Hays, Jasleen Kukreja, Ariel M. Hay, Heather L. Howie, Pearl Toy, Clifford A. Lowell, Craig N. Morrell, James C. Zimring, Mark R. Looney

Multisystem inflammatory syndrome in children and COVID-19 are distinct presentations of SARS-CoV-2

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Abstract

Background: Initial reports from the Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) pandemic described children as being less susceptible to Coronavirus Disease 2019 (COVID-19) than adults. Subsequently, a severe and novel pediatric disorder termed Multisystem Inflammatory Syndrome in Children (MIS-C) emerged. We report on unique hematologic and immunologic parameters that distinguish between COVID-19 and MIS-C and provide insight into pathophysiology. Methods: We prospectively enrolled hospitalized patients with evidence of SARS-CoV-2 infection and classified them as having MIS-C or COVID-19. Patients with COVID-19 were classified as having either minimal or severe disease. Cytokine profiles, viral cycle thresholds (Cts), blood smears, and soluble C5b-9 values were analyzed with clinical data. Twenty patients were enrolled (9 severe COVID-19, 5 minimal COVID-19, and 6 MIS-C). Five cytokines (IFN-γ, IL-10, IL-6, IL-8 and TNF-α) contributed to the analysis. TNF-α and IL-10 discriminated between patients with MIS-C and severe COVID-19. Cts and burr cells on blood smears also differentiated between patients with severe COVID-19 and those with MIS-C. Conclusion: Pediatric patients with SARS-CoV-2 are at risk for critical illness with severe COVID-19 and MIS-C. Cytokine profiling and examination of peripheral blood smears may distinguish between patients with MIS-C and severe COVID-19.

Authors

Caroline Diorio, Sarah E. Henrickson, Laura A. Vella, Kevin O. McNerney, Julie M. Chase, Chakkapong Burudpakdee, Jessica H. Lee, Cristina Jasen, Fran Balamuth, David M. Barrett, Brenda Banwell, Kathrin M. Bernt, Allison M. Blatz, Kathleen Chiotos, Brian T. Fisher, Julie C. Fitzgerald, Jeffrey S. Gerber, Kandace Gollomp, Christopher Gray, Stephan A. Grupp, Rebecca M. Harris, Todd J. Kilbaugh, Audrey R. Odom John, Michele P. Lambert, Emily J. Liebling, Michele Paessler, Whitney Petrosa, Charles A. Phillips, Anne F. Reilly, Neil Romberg, Alix E. Seif, Deborah Sesok-Pizzini, Kathleen Sullivan, Julie Vardaro, Edward M Behrens, David T. Teachey, Hamid Bassiri

Hypoxia inducible factors (HIFs) and obstructive sleep apnea

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Abstract

Intermittent hypoxia (IH) is a hallmark manifestation of obstructive sleep apnea (OSA), a widespread disorder of breathing. This review focuses on the role of hypoxia-inducible factors (HIFs) in hypertension, type 2 diabetes (T2D), and cognitive decline in experimental models of IH patterned after O2 profiles seen in OSA. IH increases HIF-1α and decreases HIF-2α protein levels. Dysregulated HIFs increase reactive oxygen species (ROS) through HIF-1-dependent activation of pro-oxidant enzyme genes in addition to reduced transcription of anti-oxidant genes by HIF-2. ROS in turn activates chemoreflex and suppresses baroreflex, thereby stimulating the sympathetic nervous system and causing hypertension. We will also discuss how increased ROS generation by HIF-1 also contributes to IH-induced insulin resistance and T2D as well as disrupted NMDA receptor signaling in the hippocampus, resulting in cognitive decline.

Authors

Nanduri R. Prabhakar, Ying-Jie Peng, Jayasri Nanduri