Alarmins, sequestered self-molecules containing damage-associated molecular patterns, are released during tissue injury to drive innate immune cell pro-inflammatory responses. Whether endogenous negative regulators controlling early immune responses are also released at the site of injury is poorly understood. Herein, we establish that the stromal cell-derived alarmin interleukin-33 (IL-33) is a local factor that directly restricts the pro-inflammatory capacity of graft infiltrating macrophages early after transplantation. By assessing heart transplant recipient samples and using a mouse heart transplant model, we establish that IL-33 is upregulated in allografts to limit chronic rejection. Mouse cardiac transplants lacking IL-33 displayed dramatically accelerated vascular occlusion and subsequent fibrosis, which was not due to altered systemic immune responses. Instead, a lack of graft IL-33 caused local augmentation of pro-inflammatory iNOS+ macrophages that accelerated graft loss. IL-33 facilitated a metabolic program in macrophages associated with reparative and regulatory functions, and local delivery of IL-33 prevented the chronic rejection of IL-33-deficient cardiac transplants. Therefore, IL-33 represents a novel regulatory alarmin in transplantation that limits chronic rejection by restraining the local activation of pro-inflammatory macrophages. The local delivery of IL-33 in extracellular matrix based-based materials may be a promising biologic for chronic rejection prophylaxis.
Tengfang Li, Zhongqiang Zhang, Joseph Guido Bartolacci, Gaelen K. Dwyer, Quan Liu, Lisa Mathews, Murugesan Velayutham, Anna Roessing, Yoojin C. Lee, Helong Dai, Sruti Shiva, Martin H. Oberbarnscheidt, Jenna L. Dziki, Steven J. Mullett, Stacy G. Wendell, James D. Wilkinson, .Steven A Webber, Michelle A. Wood-Trageser, Simon C. Watkins, Anthony J. Demetris, George S. Hussey, Stephen F. Badylak, Heth R. Turnquist
Dengue virus (DENV) infection requires cholesterol as a pro-viral factor although statin treatment did not show antiviral efficacy in dengue patients. Here, we show that DENV infection manipulates cholesterol metabolism in cells residing in low oxygen microenvironments (hypoxia) such as the liver, spleen and lymph nodes. DENV infection induced proprotein convertase subtilisin/kexin type 9 (PCSK9), which reduces low-density lipoprotein receptor (LDLR) recycling and hence cholesterol uptake. We found that, whereas LDLR uptake would have distributed cholesterol throughout the various cell compartments, de novo cholesterol synthesis enriched this lipid in the endoplasmic reticulum (ER). With cholesterol enrichment in the ER, ER-resident STING and type-I interferon (IFN) activation were repressed during DENV infection. Our in vitro findings were further supported by the finding of elevated plasma PCSK9 levels in dengue patients with high viremia and increased severity of plasma leakage. Our findings thus suggest PCSK9 plays a hitherto unrecognized role in dengue pathogenesis and therefore PCSK9 inhibitors could be a suitable host-directed treatment for dengue patients.
Esther S. Gan, Hwee Cheng Tan, Huynh Le Thi Duyen, Huynh Trung Trieu, Bridget Wills, Nabil G. Seidah, Eng Eong Ooi, Sophie Yacoub
Essential tremor is a common brain disorder affecting millions of people, yet the neuronal mechanisms underlying this prevalent disease remain elusive. Here, we show that conditional deletion of synaptotagmin-2, the fastest Ca2+-sensor for synaptic neurotransmitter release, from parvalbumin neurons in mice causes an action tremor syndrome resembling the core symptom of essential tremor patients. Combining brain region-specific and cell type-specific genetic manipulation methods, we found that deletion of synaptotagmin-2 from excitatory parvalbumin-positive neurons in cerebellar nuclei was sufficient to generate an action tremor. The synaptotagmin-2 deletion converted synchronous into asynchronous neurotransmitter release in projections from cerebellar nuclei neurons onto gigantocellular reticular nucleus neurons, which might produce an action tremor by causing signal oscillations during movement. The tremor was rescued by completely blocking synaptic transmission with tetanus toxin in cerebellar nuclei, which also reversed the tremor phenotype in the traditional harmaline-induced essential tremor model. Using a promising animal model for action tremor, our results thus characterize a synaptic circuit mechanism that may underlie the prevalent essential tremor disorder.
Mu Zhou, Maxwell D. Melin, Wei Xu, Thomas C. Sudhof
The congenital sideroblastic anemias (CSAs) can be caused by primary defects in mitochondrial iron-sulfur cluster (Fe-S) biogenesis. HSCB (heat shock cognate B), which encodes a mitochondrial co-chaperone, also known as HSC20 (heat shock cognate protein 20), is the partner of mitochondrial heat shock protein A9 (HSPA9). Together with glutaredoxin 5 (GLRX5), HSCB and HSPA9 facilitate the transfer of nascent two-iron, two-sulfur ([2Fe-2S]) clusters to recipient mitochondrial proteins. Mutations in both HSPA9 and GLRX5 have previously been associated with CSA. Therefore, we hypothesized that mutations in HSCB could also cause CSA. We screened patients with genetically undefined CSA and identified a frameshift mutation and a rare promoter variant in HSCB in a female patient with non-syndromic CSA. We found that HSCB expression was decreased in patient-derived fibroblasts and K562 erythroleukemia cells engineered to have the patient-specific promoter variant. Furthermore, gene knockdown and deletion experiments performed in K562 cells, zebrafish, and mice demonstrate that loss of HSCB results in impaired Fe-S cluster biogenesis, a defect in red blood cell hemoglobinization, the development of siderocytes, and more broadly perturbs hematopoiesis in vivo. These results further affirm the involvement of Fe-S biogenesis in erythropoiesis and hematopoiesis and define HSCB as a CSA gene.
Andrew Crispin, Chaoshe Guo, Caiyong Chen, Dean R. Campagna, Paul J. Schmidt, Daniel A. Lichtenstein, Chang Cao, Anoop K. Sendamarai, Gordon J. Hildick-Smith, Nicholas C. Huston, Jeanne Boudreaux, Sylvia S. Bottomley, Matthew M. Heeney, Barry H. Paw, Mark D. Fleming, Sarah Ducamp
The SARS-CoV-2 is the causative agent for COVID-19 pneumonia. Little is known about the kinetics, tissue distribution, cross-reactivity and neutralization antibody response in COVID-19 patients. Two groups of RT-PCR confirmed COVID-19 patients were enrolled in this study, including 12 severe patients in ICUs who needed mechanical ventilation and 11 mild patients in isolation wards. Serial clinical samples were collected for laboratory detection. Results showed that most of the severe patients had viral shedding in a variety of tissues for 20~40 days post onset of disease (8/12, 66.7%); while the majority of mild patients had viral shedding restricted to the respiratory tract and had no detectable virus RNA after 10 days post-onset (9/11, 81.8%). Mild patients showed significantly lower IgM response compared with that of the severe group. IgG responses were detected in most patients in both severe and mild groups at 9 days post onset and remained high level throughout the study. Antibodies cross-reactive to SARS-CoV and SARS-CoV-2 were detected in COVID-19 patients but not in MERS patients. High-levels of neutralizing antibodies were induced after about 10 days post onset in both severe and mild patients which were higher in the severe group. SARS-CoV-2 pseudotype neutralization test and focus reduction neutralization test with authentic virus showed consistent results. Sera from COVID-19 patients, but not convalescent SARS and MERS patients inhibited SARS-CoV-2 entry. Anti-SARS-CoV-2 S and N IgG level exhibited moderate correlation with neutralization titers in patients’ plasma. This study improves our understanding of immune response in human after SARS-CoV-2 infection.
Yanqun Wang, Lu Zhang, Ling Sang, Feng Ye, Shicong Ruan, Bei Zhong, Tie Song, Abeer N. Alshukairi, Rongchang Chen, Zhaoyong Zhang, Mian Gan, Airu Zhu, Yongbo Huang, Ling Luo, Chris KP Mok, Manal M. Al Gethamy, Haitao Tan, Zhengtu Li, Xiaofang Huang, Fang Li, Jing Sun, Yanjun Zhang, Liyan Wen, Yuming Li, Zhao Chen, Zhen Zhuang, Jianfen Zhuo, Chunke Chen, Lijun Kuang, Junxiang Wang, Huibin Lv, Yongliang Jiang, Min Li, Yimin Lin, Ying Deng, Lan Tang, Jieling Liang, Jicheng Huang, Stanley Perlman, Nanshan Zhong, Jingxian Zhao, J.S. Malik Peiris, Yimin Li, Jincun Zhao
Therapy-induced neuroendocrine prostate cancer (t-NEPC) is a highly aggressive subtype of prostate cancer with poor patient survival. Emerging evidence indicates that t-NEPC can develop when prostate adenocarcinoma cells acquire cancer stem-like cell signaling in the presence of androgen receptor inhibition, followed by re-differentiation toward neuroendocrine lineage and subsequent t-NEPC progression. Whether the stem-like signaling is controlled by the core pluripotency stem cell genes (e.g., LIN28 and SOX2) remains unknown. Here, we report that the transcription of LIN28B isoform and SOX2 are co-upregulated in t-NEPC patient tumors, patient-derived xenografts, transgenic mice, and cell models. Immunohistochemistry validated that LIN28B and SOX2 protein expression are elevated in t-NEPC patient biopsies. Using prostate adenocarcinoma and t-NEPC cell models, we demonstrated that LIN28B induces a stem-like gene network, neuroendocrine biomarkers, and neuroendocrine cell morphology. LIN28B depletion by CRISPR inhibited t-NEPC tumorigenesis and xenograft growth. These LIN28B functions were mediated mainly through the suppression of let-7 miRNA expression, resulting in de-repression of the transcription factors HMGA2 and HMGA2-mediated SOX2 expression. This study reveals a mechanism by which t-NEPC can develop through the LIN28B/let-7/SOX2 axis that regulates a cancer cell stem-like gene network, highlighting LIN28B as a potential therapeutic target in t-NEPC.
Jessica M. Lovnicki, Yu Gan, Tingting Feng, Yinan Li, Ning Xie, Chia-Hao Ho, Ahn R. Lee, Xufeng Chen, Lucia Nappi, Bo Han, Ladan Fazli, Jiaoti Huang, Martin Gleave, Xuesen Dong
Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher rates in the RNA of highly-allergenic legumes. Transcripts from peanut, soybean, sesame, and mite allergens contained a higher density of gaps than those of non-allergens. Allergen transcripts translate into proteins with a cationic carboxy-terminus depleted in hydrophobic residues. In mice, recombinant TI variants of the peanut allergen Ara h 2, but not the canonical allergen itself, induced, without adjuvant, the production of anaphylactogenic specific IgE (sIgE) binding to linear epitopes on both canonical and TI segments of the TI variants. The removal of cationic proteins from bovine lactoserum markedly reduced its capacity to induce sIgE. In peanut-allergic children, the sIgE reactivity was directed toward both canonical and TI segments of Ara h 2 variants. We discovered two novel peanut allergens because of their RNA-DNA divergence gap patterns and TI peptide amino-acid composition. Finally, we showed that the sIgE of children with IgE-negative milk allergy targeted cationic proteins in lactoserum. We propose that it is not the canonical allergens, but their TI variants, that initiate sIgE isotype switching, while both canonical and TI variants elicit clinical allergic reactions.
Benoit Thouvenot, Olivier Roitel, Julie Tomasina, Benoit Hilselberger, Christelle Richard, Sandrine Jacquenet, Françoise Codreanu-Morel, Martine Morisset, Gisèle Kanny, Etienne Beaudouin, Christine Delebarre-Sauvage, Thierry Olivry, Claude Favrot, Bernard Bihain
Utilizing the Nephrotic Syndrome Study Network Consortium and other publicly available transcriptomic datasets, we identified Retinoic acid receptor responder protein 1 (RARRES1) as a gene whose expression positively correlated with renal function decline in human glomerular disease. The glomerular expression of RARRES1, which is largely restricted to podocytes, increased in focal segmental glomerulosclerosis (FSGS) and diabetic kidney disease (DKD). Tumor necrosis factor-α (TNF-α) was a potent inducer of RARRES1 expression in cultured podocytes, and transcriptomic analysis showed the enrichment of cell death pathway genes with RARRES1 overexpression. The overexpression of RARRES1 indeed induced podocyte apoptosis in vitro. Notably, this effect was dependent on its cleavage in the extracellular domain, as the mutation of its cleavage site abolished the apoptotic effect. Mechanistically, the soluble RARRES1 is endocytosed and interacts with and inhibits RIO kinase 1 (RIOK1), resulting in p53 activation and podocyte apoptosis. In mice, podocyte-specific overexpression of RARRES1 resulted in marked glomerular injury and albuminuria, while the overexpression of RARRES1 cleavage mutant had no effect. Conversely, podocyte-specific knockdown of Rarres1 in mice ameliorated glomerular injury in the setting of Adriamycin-induced nephropathy. Together, our study demonstrates an important role and the mechanism of RARRES1 in podocyte injury in glomerular disease.
Anqun Chen, Ye Feng, Han Lai, Wenjun Ju, Zhengzhe Li, Yu Li, Andrew Wang, Quan Hong, Fang Zhong, Chengguo Wei, Jia Fu, Tian-Jun Guan, Bi-Cheng Liu, Matthias Kretzler, Kyung Lee, John Cijiang He
TGFβ is a master regulator of fibrosis, driving the differentiation of fibroblasts into apoptosis resistant myofibroblasts and sustaining the production of extracellular matrix (ECM) components. Here, we identify the nuclear lncRNA H19X as a master regulator of TGFβ-driven tissue fibrosis. H19X was consistently upregulated in a wide variety of human fibrotic tissues and diseases and was strongly induced by TGFβ, particularly in fibroblasts and fibroblast-related cells. Functional experiments following H19X silencing revealed that H19X is an obligatory factor for the TGFβ-induced ECM synthesis as well as differentiation and survival of ECM-producing myofibroblasts. We showed that H19X regulates DDIT4L gene expression, specifically interacting with a region upstream of DDIT4L gene and changing the chromatin accessibility of a DDIT4L enhancer. These events resulted in transcriptional repression of DDIT4L and, in turn, in increased collagen expression and fibrosis. Our results shed light on key effectors of the TGFβ-induced ECM remodeling and fibrosis.
Elena Pachera, Shervin Assassi, Gloria A. Salazar, Mara Stellato, Florian Renoux, Adam Wunderlin, Przemyslaw Blyszczuk, Robert Lafyatis, Fina Kurreeman, Jeska de Vries-Bouwstra, Tobias Messemaker, Carol A. Feghali-Bostwick, Gerhard Rogler, Wouter T. van Haaften, Gerard Dijkstra, Fiona Oakley, Maurizio Calcagni, Janine Schniering, Britta Maurer, Jörg H.W. Distler, Gabriela Kania, Mojca Frank-Bertoncelj, Oliver Distler
Immunotherapeutic strategies are increasingly important in neuro-oncology and the elucidation of escape mechanisms which lead to treatment resistance is crucial. We investigated the impact of immune pressure on the clonal dynamics and immune escape signature by comparing glioma growth in immunocompetent versus immunodeficient mice. Glioma-bearing wildtype and Pd-1-/- mice survived significantly longer than immunodeficient Pfp-/- Rag2-/- mice. While tumors in Pfp-/- Rag2-/- mice were highly polyclonal, immunoedited tumors in WT and Pd-1-/- mice displayed reduced clonality with emergence of immune escape clones. Tumor cells in wildtype mice were distinguished by an interferon-γ-mediated response signature with upregulation of genes involved in immunosuppression. Tumor-infiltrating stromal cells, which include macrophages/microglia, contributed even stronger to the immunosuppressive signature than the actual tumor cells. The identified murine immune escape signature was reflected in human patients and correlated with poor survival. In conclusion, immune pressure profoundly shapes the clonal composition and gene regulation in malignant gliomas.
Cecile L. Maire, Malte Mohme, Michael Bockmayr, Krystian D. Fita, Kristoffer Riecken, Daniela Börnigen, Malik Alawi, Antonio Virgilio Failla, Katharina Kolbe, Svenja Zapf, Mareike Holz, Katrin Neumann, Lasse Dührsen, Tobias Lange, Boris Fehse, Manfred Westphal, Katrin Lamszus
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