Inhibition of myristoylated alanine-rich C kinase substrate (MARCKS) protein inhibits ozone-induced airway neutrophilia and inflammation

Abstract

Evidence suggests inhibition of leukocyte trafficking mitigates, in part, ozone-induced inflammation. In the present study, the authors postulated that inhibition of myristoylated alanine-rich C kinase substrate (MARCKS), an 82-kDa protein with multiple biological roles, could inhibit ozone-induced leukocyte trafficking and cytokine secretions. BALB/c mice (n = 5/cohort) were exposed to ozone (100 ppb) or forced air (FA) for 4 hours. MARCKS-inhibiting peptides, MANS, BIO-11000, BIO-11006, or scrambled control peptide RNS, were intratracheally administered prior to ozone exposure. Ozone selectively enhanced bronchoalveolar lavage (BAL) levels of killer cells (KCs; 6 ± 0.9-fold), interleukin-6 (IL-6; 12.7 ± 1.9-fold), and tumor necrosis factor (TNF; 2.1 ± 0.5-fold) as compared to cohorts exposed to FA. Additionally, ozone increased BAL neutrophils by 21% ± 2% with no significant (P > .05) changes in other cell types. MANS, BIO-11000, and BIO-11006 significantly reduced ozone-induced KC secretion by 66% ± 14%, 47% ± 15%, and 71.1% ± 14%, and IL-6 secretion by 69% ± 12%, 40% ± 7%, and 86.1% ± 11%, respectively. Ozone-mediated increases in BAL neutrophils were reduced by MANS (86% ± 7%) and BIO-11006 (84% ± 2.5%), but not BIO-11000. These studies identify for the first time the novel potential of MARCKS protein inhibitors in abrogating ozone-induced increases in neutrophils, cytokines, and chemokines in BAL fluid. BIO-11006 is being developed as a treatment for chronic obstructive pulmonary disorder (COPD) and is currently being evaluated in a phase 2 clinical study.

A Myristoylated Alanine-Rich C Kinase Substrate–Related Peptide Suppresses Cytokine mRNA and Protein Expression in LPS-Activated Canine Neutrophils

“…Moreover, the finding that the MANS peptide is effective in attenuating MARCKS function, as opposed to the missense RNS peptide, precludes the nonspecific peptide effects that might occur with a more generalized inhibitor. Thus, our data affirm that interference with MARCKS function markedly reduces cytokine secretion, and extends the role of MARCKS protein beyond neutrophil degranulation (21) and adhesion/migration (3,4,29) into cytokine production and the regulation of mRNA transcript synthesis.…”

A rapid assessment of the impact of hazard reduction burning around Sydney, May 2016

“…Since 2005, there have been a number of key experimental animal studies carried out in mice that demonstrated acute inflammation and airway injury following acute (Damera et al, 2010) or sub-chronic exposure (Inoue et al, 2008;Yoon, Cho & Kleeberger, 2007) to environmentally pertinent ozone concentrations in the range 100-300 ppb. Additional subchronic and chronic ozone exposure studies (500 ppb) in rhesus monkeys have demonstrated structural changes in the distal and proximal airways (Fanucchi et al, 2006;Carey et al, 2011) and allergy-like patterns of response (increased globlet cells and eosinophils) to allergen and ozone co-challenges (Kajekar et al, 2007;Miller et al, 2009;van Winkle et al, 2010;Plopper et al, 2007).…”

Trichostatin A Abrogates Airway Constriction, but Not Inflammation, in Murine and Human Asthma Models

“…After centrifuging (500 3 g for 10 minutes at 4°C), the cell pellet was resuspended in RPMI medium. Differential cell counts were performed from cytospin preparations, as described elsewhere (15). Cells were identified as macrophages, eosinophils, neutrophils, and lymphocytes according to standard morphology, and a minimum of 300 cells was counted using a Nikon microscopic system (Nikon Instruments, Melville, NY) (3400 magnification).…”