Myeloid autophagy genes protect mice against fatal TNF- and LPS-induced cytokine storm syndromes

ATG5: autophagy related 5; ATG7: autophagy related 7; ATG14: autophagy related 14; ATG16L1: autophagy related 16-like 1 (S. cerevisiae); BECN1: beclin 1, autophagy related; CASP1: caspase 1; CASP4/CASP11: caspase 4, apoptosis-related cysteine peptidase; CIM: conditionally immortalized macrophage; CLP: cecal ligation and puncture; CSS: cytokine storm syndrome; DC: dendritic cell; IFNG/IFNγ: interferon gamma; IFNGR1: interferon gamma receptor 1; ip: intraperitoneal; iv: intravenous; IL12/p70: interleukin 12, p70 heterodimer; IL18: Interleukin 18; ITGAX/CD11c: integrin alpha X; LAP: LC3-associated phagocytosis; LPS: lipopolysaccharide; LYZ2/LYSM: lysozyme 2; MAP1LC3A/LC3: microtubule-associated protein 1 light chain 3 alpha; RB1CC1/FIP200: RB1-inducible coiled-coil 1; S100A8/MRP8: S100 calcium binding protein A8 (calgranulin A); TICAM1/TRIF: TIR domain containing adaptor molecule 1; TLR4: toll-like receptor 4; TNF: tumor necrosis factor

Lysoptosis is an evolutionarily conserved cell death pathway moderated by intracellular serpins

Lysosomal membrane permeabilization (LMP) and cathepsin release typifies lysosome-dependent cell death (LDCD). However, LMP occurs in most regulated cell death programs suggesting LDCD is not an independent cell death pathway, but is conscripted to facilitate the final cellular demise by other cell death routines. Previously, we demonstrated that Caenorhabditis elegans (C. elegans) null for a cysteine protease inhibitor, srp-6, undergo a specific LDCD pathway characterized by LMP and cathepsin-dependent cytoplasmic proteolysis. We designated this cell death routine, lysoptosis, to distinguish it from other pathways employing LMP. In this study, mouse and human epithelial cells lacking srp-6 homologues, mSerpinb3a and SERPINB3, respectively, demonstrated a lysoptosis phenotype distinct from other cell death pathways. Like in C. elegans, this pathway depended on LMP and released cathepsins, predominantly cathepsin L. These studies suggested that lysoptosis is an evolutionarily-conserved eukaryotic LDCD that predominates in the absence of neutralizing endogenous inhibitors

Beth Levine in memoriam

Beth Levine was born on 7 April 1960 in Newark, New Jersey. She went to college at Brown University where she received an A.B. Magna Cum Laude, and she attended medical school at Cornell University Medical College, receiving her MD in 1986. She completed her internship and residency in Internal Medicine at Mount Sinai Hospital in New York, and her fellowship in Infectious Diseases at The Johns Hopkins Hospital. Most recently, Beth was a Professor of Internal Medicine and Microbiology, Director of the Center for Autophagy Research, and holder of the Charles Sprague Distinguished Chair in Biomedical Science at the University of Texas Southwestern Medical Center in Dallas. Beth died on 15 June 2020 from cancer. Beth is survived by her husband, Milton Packer, and their two children, Rachel (26 years old) and Ben (25 years old). Dr. Levine was as an international leader in the field of autophagy research. Her laboratory identified the mammalian autophagy gene BECN1/beclin 1; identified conserved mechanisms underlying the regulation of autophagy (e.g. BCL2-BECN1 complex formation, insulin-like signaling, EGFR, ERBB2/HER2 and AKT1-mediated BECN1 phosphosphorylation); and provided the first evidence that autophagy genes are important in antiviral host defense, tumor suppression, lifespan extension, apoptotic corpse clearance, metazoan development, Na,K-ATPase-regulated cell death, and the beneficial metabolic effects of exercise. She developed a potent autophagy-inducing cell permeable peptide, Tat-beclin 1, which has potential therapeutic applications in a range of diseases. She was a founding Associate Editor of the journal Autophagy and an editorial board member of Cell and Cell Host & Microbe. She has received numerous awards/honors in recognition of her scientific achievement, including: The American Cancer Society Junior Faculty Research Award (1994); election into the American Society of Clinical Investigation (2000); the Ellison Medical Foundation Senior Scholars Award in Global Infectious Diseases (2004); elected member, American Association of Physicians (2005); appointment as a Howard Hughes Medical Institute Investigator (2008); Edith and Peter O’Donnell Award in Medicine (2008); elected fellow, American Association for the Advancement of Science (2012); election into the National Academy of Sciences (2013); election into the Academy of Medicine, Engineering and Science of Texas (2013); the ASCI Stanley J. Korsmeyer Award (2014); Phyllis T. Bodel Women in Medicine Award, Yale University School of Medicine (2018); recipient, Barcroft Medal, Queen’s University Belfast (2018).Fil: An, Zhenyi. No especifíca;Fil: Ballabi, Andrea. No especifíca;Fil: Bennett, Lynda. No especifíca;Fil: Boya, Patricia. No especifíca;Fil: Cecconi, Francesco. No especifíca;Fil: Chiang, Wei Chung. No especifíca;Fil: Codogno, Patrice. No especifíca;Fil: Colombo, Maria Isabel. No especifíca;Fil: Cuervo, Ana Maria. No especifíca;Fil: Debnath, Jayanta. No especifíca;Fil: Deretic, Vojo. No especifíca;Fil: Dikic, Ivan. No especifíca;Fil: Dionne, Keith. No especifíca;Fil: Dong, Xiaonan. No especifíca;Fil: Elazar, Zvulun. No especifíca;Fil: Galluzzi, Lorenzo. No especifíca;Fil: Gentile, Frank. No especifíca;Fil: Griffin, Diane E.. No especifíca;Fil: Hansen, Malene. No especifíca;Fil: Hardwick, J. Marie. No especifíca;Fil: He, Congcong. No especifíca;Fil: Huang, Shu Yi. No especifíca;Fil: Hurley, James. No especifíca;Fil: Jackson, William T.. No especifíca;Fil: Jozefiak, Cindy. No especifíca;Fil: Kitsis, Richard N.. No especifíca;Fil: Klionsky, Daniel J.. No especifíca;Fil: Kroemer, Guido. No especifíca;Fil: Meijer, Alfred J.. No especifíca;Fil: Meléndez, Alicia. No especifíca;Fil: Melino, Gerry. No especifíca;Fil: Mizushima, Noboru. No especifíca;Fil: Murphy, Leon O.. No especifíca;Fil: Nixon, Ralph. No especifíca;Fil: Orvedahl, Anthony. No especifíca;Fil: Pattingre, Sophie. No especifíca;Fil: Piacentini, Mauro. No especifíca;Fil: Reggiori, Fulvio. No especifíca;Fil: Ross, Theodora. No especifíca;Fil: Rubinsztein, David C.. No especifíca;Fil: Ryan, Kevin. No especifíca;Fil: Sadoshima, Junichi. No especifíca;Fil: Schreiber, Stuart L.. No especifíca;Fil: Scott, Frederick. No especifíca;Fil: Sebti, Salwa. No especifíca;Fil: Shiloh, Michael. No especifíca;Fil: Shoji, Sanae. No especifíca;Fil: Simonsen, Anne. No especifíca;Fil: Smith, Haley. No especifíca;Fil: Sumpter, Kathryn M.. No especifíca;Fil: Thompson, Craig B.. No especifíca;Fil: Thorburn, Andrew. No especifíca;Fil: Thumm, Michael. No especifíca;Fil: Tooze, Sharon. No especifíca;Fil: Vaccaro, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Virgin, Herbert W.. No especifíca;Fil: Wang, Fei. No especifíca;Fil: White, Eileen. No especifíca;Fil: Xavier, Ramnik J.. No especifíca;Fil: Yoshimori, Tamotsu. No especifíca;Fil: Yuan, Junying. No especifíca;Fil: Yue, Zhenyu. No especifíca;Fil: Zhong, Qing. No especifíca

Hepatitis C Virus Core Protein Induces Neuroimmune Activation and Potentiates Human Immunodeficiency Virus-1 Neurotoxicity

BACKGROUND: Hepatitis C virus (HCV) genomes and proteins are present in human brain tissues although the impact of HIV/HCV co-infection on neuropathogenesis remains unclear. Herein, we investigate HCV infectivity and effects on neuronal survival and neuroinflammation in conjunction with HIV infection. METHODOLOGY: Human microglia, astrocyte and neuron cultures were infected with cell culture-derived HCV or exposed to HCV core protein with or without HIV-1 infection or HIV-1 Viral Protein R (Vpr) exposure. Host immune gene expression and cell viability were measured. Patch-clamp studies of human neurons were performed in the presence or absence of HCV core protein. Neurobehavioral performance and neuropathology were examined in HIV-1 Vpr-transgenic mice in which stereotaxic intrastriatal implants of HCV core protein were performed. PRINCIPAL FINDINGS: HCV-encoded RNA as well as HCV core and non-structural 3 (NS3) proteins were detectable in human microglia and astrocytes infected with HCV. HCV core protein exposure induced expression of pro-inflammatory cytokines including interleukin-1β, interleukin-6 and tumor necrosis factor-α in microglia (p<0.05) but not in astrocytes while increased chemokine (e.g. CXCL10 and interleukin-8) expression was observed in both microglia and astrocytes (p<0.05). HCV core protein modulated neuronal membrane currents and reduced both β-III-tubulin and lipidated LC3-II expression (p<0.05). Neurons exposed to supernatants from HCV core-activated microglia exhibited reduced β-III-tubulin expression (p<0.05). HCV core protein neurotoxicity and interleukin-6 induction were potentiated by HIV-1 Vpr protein (p<0.05). HIV-1 Vpr transgenic mice implanted with HCV core protein showed gliosis, reduced neuronal counts together with diminished LC3 immunoreactivity. HCV core-implanted animals displayed neurobehavioral deficits at days 7 and 14 post-implantation (p<0.05). CONCLUSIONS: HCV core protein exposure caused neuronal injury through suppression of neuronal autophagy in addition to neuroimmune activation. The additive neurotoxic effects of HCV- and HIV-encoded proteins highlight extrahepatic mechanisms by which HCV infection worsens the disease course of HIV infection

Autophagy in Antiviral Immunity

Autophagy is an evolutionarily conserved pathway in which cytoplasmic material is sequestered in a double-membrane vesicle and delivered to the lysosome for degradation. During times of stress, autophagy functions to generate essential nutrients through the degradation of non-essential cytoplasmic contents. It is also the only known mechanism for removal of damaged or superfluous organelles and cytoplasmic contents that are too large to be degraded by the proteasome. Given the critical role for autophagy in stress response and in maintaining cell cytoplasmic quality control, it is not surprising that autophagy plays an essential role in the host response to infection, and that microbes have evolved mechanisms to counteract or evade autophagy. In this work, we studied the role of autophagy inhibition in a mouse model of herpes simplex virus type I (HSV-1) encephalitis, investigated the role of autophagy in protection against Sindbis virus infection of the central nervous system, and identified novel host genes involved in targeting viral proteins to the autophagy pathway. We found that the HSV-1 encoded neurovirulence protein ICP34.5 interacted with the host autophagy protein Beclin 1, and that this interaction was essential for HSV-1 neurovirulence. This was the first example of a viral virulence protein that targets host autophagy, and provided evidence that autophagy functions in innate immunity to viruses. In the second study, we found that the host autophagy gene Atg5 was required to protect against lethal Sindbis virus CNS diseases, and that autophagy targeted viral proteins for degradation in brains of infected mice and cells in vitro. We found that the autophagy adaptor protein p62 was involved in targeting viral proteins for autophagic degradation and this promoted survival of infected cells. This study demonstrated that clearance of viral proteins by autophagy was an important mechanism for cellular and organismal survival during viral infection. Lastly, we performed a genome-wide siRNA screen to identify novel host factors required for autophagic targeting of viral proteins. We identified previously unappreciated cellular networks and genes that were involved in targeting viral proteins for autophagy. One of these factors, SMURF1, is an E3 ubiquitin ligase that not only functions to target viral proteins, but is also involved in targeting damaged mitochondria for autophagic clearance