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.
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
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.
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
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.
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
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.
Ke Jin, Zhenke Wen, Bowen Wu, Hui Zhang, Jingtao Qiu, Yanan Wang, Kenneth J. Warrington, Gerald Berry, Jörg J. Goronzy, Cornelia M. Weyand
Inborn errors of TLR3-dependent IFN-α/β- and -λ-mediated immunity in the central nervous system (CNS) can underlie herpes simplex virus 1 (HSV-1) encephalitis (HSE). The respective contributions of IFN-α/β and -λ are unknown. We report a child homozygous for a genomic deletion of the entire coding sequence and part of the 3’UTR of the last exon of IFNAR1, who died from HSE at the age of two years. An older cousin died following vaccination against measles, mumps and rubella at 12 months of age, and another 17-year-old cousin homozygous for the same variant has had other, less severe viral illnesses. The encoded IFNAR1 protein is expressed on the cell surface but is truncated and cannot interact with the tyrosine kinase TYK2. The patient’s fibroblasts and EBV-B cells did not respond to IFN-α2b or IFN-β, in terms of STAT1, STAT2 and STAT3 phosphorylation, or the genome-wide induction of IFN-stimulated genes. The patient’s fibroblasts were susceptible to viruses, including HSV-1, even in the presence of exogenous IFN-α2b or IFN-β. HSE is therefore a consequence of inherited complete IFNAR1 deficiency. This viral disease occurred in natural conditions, unlike those previously reported in other patients with IFNAR1 or IFNAR2 deficiency. This experiment of Nature indicates that IFN-α/β are essential for anti-HSV-1 immunity in the CNS.
Paul Bastard, Jeremy Manry, Jie Chen, Jérémie Rosain, Yoann Seeleuthner, Omar AbuZaitun, Lazaro Lorenzo, Taushif Khan, Mary Hasek, Nicholas Hernandez, Benedetta Bigio, Peng Zhang, Romain Lévy, Shai Shrot, Eduardo J. Garcia Reino, Yoon Seung Lee, Soraya Boucherit, Mélodie Aubart, Rik Gijsbers, Vivien Béziat, Zhi Li, Sandra Pellegrini, Isabelle Meyts, Flore Rozenberg, Nico Marr, Bertrand Boisson, Aurélie Cobat, Jacinta Bustamante, Qian Zhang, Emmanuelle Jouanguy, Laurent Abel, Raz Somech, Jean-Laurent Casanova, Shen-Ying Zhang
Estrogen receptor (ER)-negative breast cancer is thought to be more malignant and devastating than ER-positive breast cancer and exhibit elevated NF-κB activity. How abnormally high NF-κB activity is maintained in ER-negative breast cancer is poorly understood. The importance of linear ubiquitination, which is generated by the linear ubiquitin chain assembly complex (LUBAC), is increasingly appreciated in NF-κB signaling, which regulates cell activation and death. Here, we showed that epsin proteins, a family of ubiquitin-binding endocytic adaptors, interacted with LUBAC via its Ubiquitin-Interacting Motif (UIM) and bound LUBAC’s bona fide substrate NEMO via its N-terminal homolog (ENTH) domain. Furthermore, epsins promoted NF-κB essential modulator (NEMO) linear ubiquitination and served as scaffolds for recruiting other components of the IκB kinase (IKK) complex; thereby, resulting in the heightened IKK activation and sustained NF-κB signaling essential for the development of ER-negative breast cancer. Heightened epsin levels in ER-negative human breast cancer are associated with poor, relapse-free survival. We showed that transgenic and pharmacological approaches eliminating epsins potently impeded breast cancer development in both spontaneous and patient-derived xenograft breast cancer mouse models. Our findings established the pivotal role epsins played in promoting breast cancer. Thus, targeting epsins may represent a strategy to restrain NF-κB signaling, and provide an important perspective into ER-negative breast cancer treatment.
Kai Song, Xiaofeng Cai, Yunzhou Dong, Hao Wu, Yong Wei, Uma Shankavaram, Kui Cui, Yang Lee, Bo Zhu, Sudarshan Bhattacharjee, Beibei Wang, Kun Zhang, Aiyun Wen, Scott Wong, Lili Yu, Lijun Xia, Alana L Welm, Diane R. Bielenberg, Kevin Camphausen, Yibin Kang, Hong Chen
Macrophages are main effectors of heme metabolism, increasing transiently in the liver during heightened disposal of damaged or senescent red blood cells (sRBC). Macrophages are also essential in defense against microbial threats, but pathologic states of heme excess may be immunosuppressive. Herein, we uncovered a mechanism whereby an acute rise in sRBC disposal by macrophages led to an immunosuppressive phenotype following intrapulmonary Klebsiella pneumoniae infection characterized by increased extrapulmonary bacterial proliferation and reduced survival from sepsis in mice. The impaired immunity to K. pneumoniae during heightened sRBC disposal was independent of iron acquisition by bacterial siderophores, as K. pneumoniae mutant lacking siderophore function recapitulated findings observed with wildtype strain. Rather, sRBC disposal induced a liver transcriptomic profile notable for suppression of Stat1 and interferon-related responses during K. pneumoniae sepsis. Excess heme handling by macrophages recapitulated STAT1 suppression during infection that required synergistic NRF1 and NRF2 activation but was independent of heme oxygenase-1 induction. Whereas iron was dispensable, the porphyrin moiety of heme was sufficient to mediate suppression of STAT1-dependent responses in human and mouse macrophages and promoted liver dissemination of K. pneumoniae in vivo. Thus, cellular heme metabolism dysfunction negatively regulates the STAT1 pathway with implications in severe infection.
Tolani F. Olonisakin, Tomeka L. Suber, Shekina Gonzalez-Ferrer, Zeyu Xiong, Hernán F. Peñaloza, Rick van der Geest, Yuting Xiong, David O. Osei-Hwedieh, Jesus Tejero, Matthew R. Rosengart, Wendy M. Mars, Daria Van Tyne, Andreas Perlegas, Samuel Brashears, Daniel B. Kim-Shapiro, Mark T. Gladwin, Michael A. Bachman, Eldad A. Hod, Claudette St. Croix, Yulia Y. Tyurina, Valerian E. Kagan, Rama K. Mallampalli, Anuradha Ray, Prabir Ray, Janet S. Lee
RNA binding protein Apobec1 Complementation Factor (A1CF) regulates posttranscriptional ApoB mRNA editing but the range of RNA targets and long-term impact of altered A1CF expression on liver function are unknown. Here we studied hepatocyte-specific A1cf transgenic (A1cf +/Tg), A1cf+/Tg Apobec1–/– and A1cf –/– mice fed chow or high fat/high fructose diets using RNA-Seq, RNA-CLIP Seq and tissue microarrays from human hepatocellular cancer (HCC). A1cf +/Tg mice exhibited increased hepatic proliferation and steatosis, with increased lipogenic gene expression (Mogat1, Mogat2, Cidea, Cd36) associated with shifts in polysomal RNA distribution. Aged A1cf +/Tg mice developed spontaneous fibrosis, dysplasia and HCC, which was accelerated on a high fat/fructose diet and independent of Apobec1. RNA-Seq revealed increased expression of mRNAs involved in oxidative stress (Gstm3, Gpx3, Cbr3), inflammatory response (Il19, Cxcl14, Tnfα, Ly6c), extracellular matrix organization (Mmp2, Col1a1, Col4a1), proliferation (Kif20a, Mcm2, Mcm4, Mcm6) with a subset of mRNAs (including Sox4, Sox9, Cdh1) identified in RNA CLIP-Seq. Increased A1CF expression in human HCC correlated with advanced fibrosis and with reduced survival in a subset with nonalcoholic fatty liver disease. In conclusion, we show that hepatic A1CF overexpression selectively alters polysomal distribution and mRNA expression, promoting lipogenic, proliferative and inflammatory pathways leading to HCC.
Valerie Blanc, Jesse D. Riordan, Saeed Soleymanjahi, Joseph Nadeau, ILKe Nalbantoglu, Yan Xie, Elizabeth A. Molitor, Blair B. Madison, Elizabeth M. Brunt, Jason C. Mills, Deborah C. Rubin, Irene O.L. Ng, Yeonjung Ha, Lewis R. Roberts, Nicholas O. Davidson
CD4+ T cells interactions with B cells play a critical role in the pathogenesis of systemic autoimmune diseases such as systemic lupus and chronic graft-versus-host disease (cGVHD). Extrafollicular CD44hiCD62LloPSGL1loCD4+ (PSGL1loCD4+) T cells are associated with the pathogenesis of lupus and cGVHD, but their causal role has not been established. With murine and humanized MHC–/–HLA-A2+DR4+ murine models of cGVHD, we show that both murine and human PSGL1loCD4+ T cells from GVHD target tissues have features of B cell helpers with upregulated-expression of PD1 and ICOS and production of IL-21. They reside in non-lymphoid tissues without circulating in the blood and have features of tissue-resident memory T cells with upregulated-expression of CD69. Murine PSGL1loCD4+ T cells from GVHD target tissues augmented B cell differentiation into plasma cells and production of autoantibodies via their PD1 interaction with PD-L2 on B cells. Human PSGL1loCD4+ T cells were apposed with memory B cells in the liver tissues of humanized mice and cGVHD patients. Human PSGL1loCD4+ T cells from humanized GVHD target tissues also augmented autologous memory B cell differentiation into plasma cells and antibody production in PD1/PD-L2-dependent manner. Further preclinical studies targeting tissue-resident T cells to treat antibody-mediated features of autoimmune diseases are warranted.
Xiaohui Kong, Deye Zeng, Xiwei Wu, Bixin Wang, Shijie Yang, Qingxiao Song, Yongping Zhu, Martha Salas, Hanjun Qin, Ubaydah Nasri, Karen M. Haas, Arthur D. Riggs, Ryotaro Nakamura, Paul J. Martin, Aimin Huang, Defu Zeng
Therapeutic strategies designed to target TP53-deficient cancer cells remain elusive. Here, we showed that TP53 loss initiated a pharmacologically actionable secretory process that drove lung adenocarcinoma (LUAD) progression. Molecular, biochemical, and cell biological studies showed that TP53 loss increased the expression of Golgi reassembly and stacking protein 55 kD (G55), a Golgi stacking protein that maintains Golgi organelle integrity and is part of a GOLGIN45/myosin IIA-containing protein complex that activates secretory vesicle biogenesis in the Golgi. TP53 loss activated G55-dependent secretion by relieving G55 and myosin IIA from miR-34a-dependent silencing. G55-dependent secreted proteins enhanced the proliferative and invasive activities of TP53-deficient LUAD cells and promoted angiogenesis and CD8+ T cell exhaustion in the tumor microenvironment. A small molecule that blocks G55/G45 interactions impaired secretion and reduced TP53-deficient LUAD growth and metastasis. These results identified a targetable secretory vulnerability in TP53-deficient LUAD cells.
Xiaochao Tan, Lei Shi, Priyam Banerjee, Xin Liu, Hou-Fu Guo, Jiang Yu, Neus Bota-Rabassedas, B. Leticia Rodriguez, Don L. Gibbons, William K. Russell, Chad J. Creighton, Jonathan M. Kurie
No posts were found with this tag.