Regular Article
Calpain Contributes to Silica-Induced IκB-α Degradation and Nuclear Factor-κB Activation

https://doi.org/10.1006/abbi.1997.0132Get rights and content

Abstract

Both silica and lipopolysaccharide (LPS) induce a rapid degradation of IκBα, an intracellular inhibitor of the nuclear factor (NF)-κB transcription factor. In this report, we demonstrate that MG132, a relatively specific proteasome inhibitor, is capable of suppressing LPS-induced IκBα degradation and NF-κB activation in mouse macrophage line RAW 264.7 cells, but is unable to influence the same induction produced by silica. In contrast, the lysosome inhibitor chloroquine has little effect on IκBα degradation induced by either silica or LPS. In fact, chloroquine enhances the signal-induced nuclear expression of NF-κB p50/p65 heterodimer by inhibiting the resynthesis of IκBα. With the use of transient transfection of a plasmid that expresses calpastatin, a natural inhibitor for calpain, the silica-induced degradation of IκBα and NF-κB activation was attenuated. In contrast, no inhibition of LPS-induced IκBα degradation and NF-κB activation was observed by the overexpression of calpastatin. This suggests that calpain contributes to silica-induced IκBα degradation and NF-κB activation but not to LPS-induced IκBα degradation and NF-κB activation.

References (28)

  • K.K.W. Wang et al.

    Trends Pharmacol. Sci.

    (1994)
  • E.B. Kopp et al.

    Adv. Immunol.

    (1995)
  • D. Thanos et al.

    Cell

    (1995)
  • L. Baldi et al.

    J. Biol. Chem.

    (1996)
  • M. Roff et al.

    J. Biol. Chem.

    (1996)
  • V.J. Palombella et al.

    Cell

    (1994)
  • K.K.W. Wang et al.

    Adv. Pharmacol.

    (1996)
  • F. Chen et al.

    Biochem. Biophys. Res. Commun.

    (1995)
  • F. Chen et al.

    Biochem. Biophys. Res. Commun.

    (1995)
  • W.J. Lee et al.

    J. Biol. Chem.

    (1992)
  • Z. Chen et al.

    Cell

    (1996)
  • P.A. Baeuerle et al.

    Cell

    (1996)
  • A. Ciechanover

    Cell

    (1994)
  • Cited by (66)

    • A Novel Mechanism for NF-kB-activation via IkB-aggregation: Implications for Hepatic Mallory-Denk-Body Induced Inflammation

      2020, Molecular and Cellular Proteomics
      Citation Excerpt :

      Thus, we excluded two such established mechanisms: (i) Translational suppression of IκBα upon activation of the heme-regulated inhibitor (HRI) eIF2α kinase through NMPP-elicited heme-deficiency, by documenting that HRI-genetic ablation failed to affect such NMPP-elicited IκBα-loss in mouse hepatocytes [(56); Figs. 1D and supplemental Fig. S2A]; and (ii) enhanced IκBα autophagy by documenting that such an IκBα-loss in MEF cells was unaffected by ATG5-knockout (KO) [(57); supplemental Fig. S2B]. Additionally, we also excluded two plausible mechanisms: (iii) Enhanced calpain-mediated proteolysis of IκBα by documenting that such a loss was unaffected in MEF cells upon genetic calpain-KO [(58); supplemental Fig.S2C]; and (iv) PPIX-photoactivation and consequent ROS-mediated oxidative stress (28) in NMPP-elicited IκBα-loss through the use of specific ROS scavengers, antioxidants and/or inhibitors (Supplemental Results; supplemental Fig. S3). Because NMPP-elicited ferrochelatase inhibition results in PPIX-accumulation, we examined whether this accumulation (and not heme deficiency per se) was mainly responsible for the observed IκBα-loss and NF-κB activation.

    • Calpeptin attenuates cigarette smoke-induced pulmonary inflammation via suppressing calpain/IκBα signaling in mice and BEAS-2B cells

      2018, Pathology Research and Practice
      Citation Excerpt :

      Individual differences in inflammatory response and differences in repair capacity of CS-induced destruction by reactive oxygen species were likely genetically inherent [31]. Calpains play an vital role in IκBα degradation to activate NF-кB in a T-cell activation model and non–T-cell models [32]. Calpains degraded silica-induced IκBα, then activated NF-кB but did not lead to lipopolysaccharide-induced IκBα degradation and NF-kB activation [32].

    • Calpain-2 contributes to neuropathic pain following motor nerve injury via up-regulating interleukin-6 in DRG neurons

      2015, Brain, Behavior, and Immunity
      Citation Excerpt :

      In our in vivo study, we observed a dose-independent transient allodynia induced by rr-CALP2 (Fig. 6G–I), suggesting that calpain-2 might be a mediator but was not the only one to trigger pain. Calpain-2-mediated cascade responses, such as the activation of nuclear factor-kappa B (NF-κB) (Chen et al., 1997; Fenouille et al., 2012; Lee et al., 2005; Schaecher et al., 2004; Shumway et al., 1999) and the subsequent secretion of pro-inflammatory cytokines (Iguchi-Hashimoto et al., 2011; Uceyler et al., 2007) might play more important roles in the development of chronic pain (He et al., 2010; Wei et al., 2013a; Xu et al., 2006; Zang et al., 2010). Earlier studies have confirmed that the activity of calpain is able to be regulated by its association with its intrinsic inhibitor calpastatin (Guroff, 1964; Murachi et al., 1989).

    • Long-term incubation with proteasome inhibitors (PIs) induces IκBα degradation via the lysosomal pathway in an IκB kinase (IKK)-dependent and IKK-independent manner

      2013, Journal of Biological Chemistry
      Citation Excerpt :

      There are several circumstances in which participation of other protein degradation systems have been described. The calcium-activated calpain system (25–26), caspases (27), lysosomes (28), and unknown proteinases have been suggested to be responsible for IκB degradation. In this study, lysosomal inhibitor (chloroquine or NH4Cl) and cathepsin inhibitors (Z-FF-FMK or Z-FA-FMK) suppressed PI-induced IκBα degradation, but did not affect TNF-α-mediated IκBα degradation in NCI-H157 cells and lipopolysaccharide (LPS) or CpG-oligodeooxynucleotide (CpG-ODN)-induced IκBα degradation in macrophage cell line (data not shown).

    View all citing articles on Scopus
    1

    To whom correspondence should be addressed. Fax: 717-531-5380. E-mail: [email protected].

    View full text