title: A role for stefin B (cystatin B) in inflammation and endotoxemia.
abstract: Stefin B (cystatin B) is an endogenous cysteine cathepsin inhibitor, and the loss-of-function mutations in the stefin B gene were reported in patients with Unverricht-Lundborg disease (EPM1). In this study we demonstrated that stefin B-deficient (StB KO) mice were significantly more sensitive to the lethal LPS-induced sepsis and secreted higher amounts of pro-inflammatory cytokines IL-1β and IL-18 in the serum. We further showed that increased caspase-11 gene expression and better pro-inflammatory caspase-1 and -11 activation determined in StB KO bone marrow-derived macrophages resulted in enhanced IL-1β processing. Pretreatment of macrophages with the cathepsin inhibitor E-64d did not affect secretion of IL-1β, suggesting that the increased cathepsin activity determined in StB KO bone marrow-derived macrophages is not essential for inflammasome activation. Upon LPS stimulation, stefin B was targeted into the mitochondria, and the lack of stefin B resulted in the increased destabilization of mitochondrial membrane potential and mitochondrial superoxide generation. Collectively, our study demonstrates that the LPS-induced sepsis in StB KO mice is dependent on caspase-11 and mitochondrial reactive oxygen species but is not associated with the lysosomal destabilization and increased cathepsin activity in the cytosol.
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Jožef Stefan International Postgraduate School, Jamova 39, Ljubljana SI-1000, Slovenia,; Department of Biochemistry and Molecular Biology, College of Medicine, Penn State University, Hershey, Pennsylvania 17033.
authors.forename: Katarina
authors.initials: K
authors.lastname: Maher
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Jožef Stefan International Postgraduate School, Jamova 39, Ljubljana SI-1000, Slovenia.
authors.forename: Barbara
authors.initials: B
authors.lastname: Jerič Kokelj
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Jožef Stefan International Postgraduate School, Jamova 39, Ljubljana SI-1000, Slovenia.
authors.forename: Miha
authors.initials: M
authors.lastname: Butinar
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Jožef Stefan International Postgraduate School, Jamova 39, Ljubljana SI-1000, Slovenia.
authors.forename: Georgy
authors.initials: G
authors.lastname: Mikhaylov
authors.affiliation: Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia,; EN-FIST Centre of Excellence, SI-1000 Ljubljana, Slovenia.
authors.forename: Mateja
authors.initials: M
authors.lastname: Manček-Keber
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Jožef Stefan International Postgraduate School, Jamova 39, Ljubljana SI-1000, Slovenia.
authors.forename: Veronika
authors.initials: V
authors.lastname: Stoka
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia.
authors.forename: Olga
authors.initials: O
authors.lastname: Vasiljeva
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,; Centre of Excellence for Integrated Approaches in Chemistry and Biology of Proteins (CIPKeBiP), Jamova 39, SI-1000 Ljubljana, Slovenia,; Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Cesta v Mestni log 88A, SI-1000 Ljubljana, Slovenia, and.
authors.forename: Boris
authors.initials: B
authors.lastname: Turk
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, Penn State University, Hershey, Pennsylvania 17033.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Grigoryev
authors.affiliation: Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana SI-1000, Slovenia,. Electronic address: natasa.kopitar@ijs.si.
authors.forename: Nataša
authors.initials: N
authors.lastname: Kopitar-Jerala
mesh_terms: D000818:Animals; D020169:Caspases / Q000378:metabolism; D053471:Caspases, Initiator; D055313:Cystatin B / Q000502:physiology*; D019446:Endotoxemia / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D005786:Gene Expression Regulation; D058847:Inflammasomes / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism*; D008070:Lipopolysaccharides; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008928:Mitochondria / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: C524992:Cstb protein, mouse; D058847:Inflammasomes; D008070:Lipopolysaccharides; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D055313:Cystatin B; C101136:Casp4 protein, mouse; D020169:Caspases; D053471:Caspases, Initiator
keywords: Caspase; Inflammasome; Mitochondria; Reactive Oxygen Species (ROS); Sepsis