Hemin and Cobalt Protoporphyrin Inhibit NLRP3 Inflammasome Activation by Enhancing Autophagy: A Novel Mechanism of Inflammasome Regulation

Inflammasomes are intracellular protein platforms, which, upon activation, produce the highly proinflammatory cytokines interleukin (IL)-1β and IL-18. Heme, hemin and their degradation products possess significant immunomodulatory functions. Here, we studied whether hemin regulates inflammasome function in macrophages. Both hemin and its derivative, cobalt protoporphyrin (CoPP), significantly reduced IL-1β secretion by cultured human primary macrophages, the human monocytic leukemia cell line and also mouse bone marrow-derived and peritoneal macrophages. Intraperitoneal administration of CoPP to mice prior to urate crystal-induced peritonitis alleviated IL-1β secretion to the peritoneal cavity. In cultured macrophages, hemin and CoPP inhibited NLRP3 inflammasome assembly by reducing the amount of intracellular apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC). The reduction of ASC was associated with enhanced autophagosome formation and autophagic flux. Inhibition of autophagy prevented the CoPP-induced depletion of ASC, implying that the depletion was caused by increased autophagy. Our data indicate that hemin functions as an endogenous negative regulator of the NLRP3 inflammasome. The inhibition is mediated via enhanced autophagy that results in increased degradation of ASC. This regulatory mechanism may provide a novel approach for the treatment of inflammasome-related diseases.

[1]  C. Stehlik,et al.  COPs and POPs: Modulators of Inflammasome Activity1 , 2007, The Journal of Immunology.

[2]  N. Abraham,et al.  Pharmacological and Clinical Aspects of Heme Oxygenase , 2008, Pharmacological Reviews.

[3]  M. Soares,et al.  Heme Cytotoxicity and the Pathogenesis of Immune-Mediated Inflammatory Diseases , 2012, Front. Pharmacol..

[4]  Jiwei Yao,et al.  Heme Induces IL-1β Secretion Through Activating NLRP3 in Kidney Inflammation , 2014, Cell Biochemistry and Biophysics.

[5]  A. Porter,et al.  Critical role for cathepsin B in mediating caspase-1-dependent interleukin-18 maturation and caspase-1-independent necrosis triggered by the microbial toxin nigericin , 2003, Cell Death and Differentiation.

[6]  Hong Li,et al.  Induction of heme oxygenase-1 attenuates lipopolysaccharide-induced inflammasome activation in human gingival epithelial cells. , 2014, International journal of molecular medicine.

[7]  N. Mizushima.  Methods for monitoring autophagy. , 2004, The international journal of biochemistry & cell biology.

[8]  Elizabeta Nemeth,et al.  Iron homeostasis in host defence and inflammation , 2015, Nature reviews. Immunology.

[9]  Haitao Wen,et al.  The inflammasome NLRs in immunity, inflammation, and associated diseases. , 2011, Annual review of immunology.

[10]  C. Fader,et al.  Hemin induces mitophagy in a leukemic erythroblast cell line , 2016, Biology of the cell.

[11]  M. Rosengart,et al.  Heme oxygenase‐1–mediated autophagy protects against hepatocyte cell death and hepatic injury from infection/sepsis in mice , 2011, Hepatology.

[12]  Shangha Pan,et al.  Hemin inhibits NLRP3 inflammasome activation in sepsis-induced acute lung injury, involving heme oxygenase-1. , 2014, International immunopharmacology.

[13]  A. Landar,et al.  Hemin causes mitochondrial dysfunction in endothelial cells through promoting lipid peroxidation: the protective role of autophagy. , 2012, American journal of physiology. Heart and circulatory physiology.

[14]  L. Punzi,et al.  High-density lipoproteins downregulate CCL2 production in human fibroblast-like synoviocytes stimulated by urate crystals , 2010, Arthritis research & therapy.

[15]  C. Piantadosi,et al.  Nrf2 promotes alveolar mitochondrial biogenesis and resolution of lung injury in Staphylococcus aureus pneumonia in mice. , 2012, Free radical biology & medicine.

[16]  Shangha Pan,et al.  Hemin inhibits NLRP 3 in fl ammasome activation in sepsis-induced acute lung injury , involving heme oxygenase-1 , 2014 .

[17]  Egil Lien,et al.  NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals , 2010, Nature.

[18]  W. Reith,et al.  Conditional gene targeting in macrophages and granulocytes using LysMcre mice , 1999, Transgenic Research.

[19]  W. Xiong,et al.  Epstein-Barr Virus miR-BART6-3p Inhibits the RIG-I Pathway , 2017, Journal of Innate Immunity.

[20]  J. Tschopp,et al.  Autophagy Controls IL-1β Secretion by Targeting Pro-IL-1β for Degradation , 2011, The Journal of Biological Chemistry.

[21]  N. Mizushima,et al.  p62 targeting to the autophagosome formation site requires self-oligomerization but not LC3 binding , 2011, The Journal of cell biology.

[22]  P. Naughton,et al.  Cardioprotective Actions by a Water‐Soluble Carbon nMonoxide‐Releasing Molecule , 2003, Circulation research.

[23]  N. Mizushima,et al.  The role of Atg proteins in autophagosome formation. , 2011, Annual review of cell and developmental biology.

[24]  S. Kim,et al.  NLRP3 inflammasome activation in D-galactosamine and lipopolysaccharide-induced acute liver failure: role of heme oxygenase-1. , 2013, Free radical biology & medicine.

[25]  G. Kollias,et al.  Myeloid heme oxygenase–1 regulates innate immunity and autoimmunity by modulating IFN-β production , 2009, The Journal of experimental medicine.

[26]  P. Kovanen,et al.  Cholesterol Crystals Activate the NLRP3 Inflammasome in Human Macrophages: A Novel Link between Cholesterol Metabolism and Inflammation , 2010, PloS one.

[27]  E. Alnemri,et al.  Cutting Edge: NF-κB Activating Pattern Recognition and Cytokine Receptors License NLRP3 Inflammasome Activation by Regulating NLRP3 Expression1 , 2009, The Journal of Immunology.

[28]  P. Kovanen,et al.  Ethanol Inhibits Activation of NLRP3 and AIM2 Inflammasomes in Human Macrophages–A Novel Anti-Inflammatory Action of Alcohol , 2013, PloS one.

[29]  G. Bjørkøy,et al.  A reporter cell system to monitor autophagy based on p62/SQSTM1 , 2010, Autophagy.

[30]  F. Martinon,et al.  Gout-associated uric acid crystals activate the NALP3 inflammasome , 2006, Nature.

[31]  김영삼.  Carbon monoxide activates autophagy via mitochondrial reactive oxygen species formation , 2011 .

[32]  G. Pedraza-Alva,et al.  Negative regulation of the inflammasome: keeping inflammation under control , 2015, Immunological reviews.

[33]  V. Deretic,et al.  Autophagy‐based unconventional secretory pathway for extracellular delivery of IL‐1β , 2011, The EMBO journal.

[34]  E. Latz,et al.  Activation and regulation of the inflammasomes , 2013, Nature Reviews Immunology.

[35]  Katherine A. Fitzgerald,et al.  Unified Polymerization Mechanism for the Assembly of ASC-Dependent Inflammasomes , 2014, Cell.

[36]  D. Golenbock,et al.  Hemolysis-induced lethality involves inflammasome activation by heme , 2014, Proceedings of the National Academy of Sciences.

[37]  A. Sher,et al.  Activation of autophagy by inflammatory signals limits IL-1β production by targeting ubiquitinated inflammasomes for destruction , 2012, Nature Immunology.

[38]  K. Moore,et al.  NLRP3 inflamasomes are required for atherogenesis and activated by cholesterol crystals that form early in disease , 2010, Nature.

[39]  Xiangmei Zhou,et al.  A role for mitochondria in NLRP3 inflammasome activation , 2011, Nature.

[40]  M. Baumann,et al.  Serum Amyloid A Activates the NLRP3 Inflammasome via P2X7 Receptor and a Cathepsin B-Sensitive Pathway , 2011, The Journal of Immunology.

[41]  Zhang Jianli,et al.  Induction of heme oxygenase-1 attenuates lipopolysaccharide-induced inflammasome activation in human gingival epithelial cells. , 2014 .

[42]  A. Porter,et al.  Expression Analysis of the Human Caspase-1 Subfamily Reveals Specific Regulation of the CASP5 Gene by Lipopolysaccharide and Interferon-γ* , 2000, The Journal of Biological Chemistry.