BET Bromodomain Inhibitors Suppress Inflammatory Activation of Gingival Fibroblasts and Epithelial Cells From Periodontitis Patients

Abstract

BET bromodomain proteins are important epigenetic regulators of gene expression that bind acetylated histone tails and regulate the formation of acetylation-dependent chromatin complexes. BET inhibitors suppress inflammatory responses in multiple cell types and animal models, and protect against bone loss in experimental periodontitis in mice. Here, we analyzed the role of BET proteins in inflammatory activation of gingival fibroblasts (GFs) and gingival epithelial cells (GECs). We show that the BET inhibitors I-BET151 and JQ1 significantly reduced expression and/or production of distinct, but overlapping, profiles of cytokine-inducible mediators of inflammation and bone resorption in GFs from healthy donors ( IL6, IL8, IL1B, CCL2, CCL5, COX2 , and MMP3 ) and the GEC line TIGK ( IL6, IL8, IL1B, CXCL10, MMP9 ) without affecting cell viability. Activation of mitogen-activated protein kinase and nuclear factor-κB pathways was unaffected by I-BET151, as was the histone acetylation status, and new protein synthesis was not required for the anti-inflammatory effects of BET inhibition. I-BET151 and JQ1 also suppressed expression of inflammatory cytokines, chemokines, and osteoclastogenic mediators in GFs and TIGKs infected with the key periodontal pathogen Porphyromonas gingivalis . Notably, P. gingivalis internalization and intracellular survival in GFs and TIGKs remained unaffected by BET inhibitors. Finally, inhibition of BET proteins significantly reduced P. gingivalis -induced inflammatory mediator expression in GECs and GFs from patients with periodontitis. Our results demonstrate that BET inhibitors may block the excessive inflammatory mediator production by resident cells of the gingival tissue and identify the BET family of epigenetic reader proteins as a potential therapeutic target in the treatment of periodontal disease.

Candida albicans Shields the Periodontal Killer Porphyromonas gingivalis from Recognition by the Host Immune System and Supports the Bacterial Infection of Gingival Tissue

“…Fibroblasts were isolated from gingival tissue specimens as described previously [68]. Briefly, the cells were collected from healthy individuals undergoing orthodontic treatment (n = 6) and from patients with chronic periodontitis (n = 5) at our facility.…”

“…A wild-type strain of P. gingivalis, W83 (was obtained from Prof. Jan Potempa, Jagiellonian University in Krakow) was grown in anaerobic cultures for 5-7 days at 37 • C on blood agar plates as described previously [68]. The bacteria were then inoculated into brain-heart infusion (BHI) broth (BD Biosciences, Franklin Lakes, NJ, USA) supplemented with 0.5 mg mL −1 cysteine, 10 µg mL −1 hemin, and 0.5 µg mL −1 vitamin K and cultured overnight in an anaerobic chamber (85% N 2 , 10% CO 2 , and 5% H 2 ).…”

GBAF, a small BAF sub-complex with big implications: a systematic review

“…This recognition allows for the modulation of cellular functions like chromatin remodeling and gene transcription. The discovery that several BRD-containing proteins are involved in inflammation [ 109 , 110 ] and tumorigenesis [ 111 ] has made them a compelling target for small-molecule inhibition studies [ 112 ]. One of the first selective inhibition studies focused on BRD4 [ 113 ], a BRD9 paralog and BRD-containing protein family member with epigenetic mediatory activities and known roles in cancers, including chronic lymphocytic leukemia [ 114 ] and human squamous carcinoma [ 115 ].…”

Network Pharmacology Analysis of the Therapeutic Mechanisms Underlying Beimu-Gualou Formula Activity against Bronchiectasis with In Silico Molecular Docking Validation

“…In addition, constitutive MAPK1 activation also lies at the nexus of CXCL8-triggered neutrophil migration via interceding CXCL8 expression [ 49 , 50 ]. Through synergistic action with other enzymes, MMP9 induces the inactivation of antileukocyte protease and subsequently aggravates inflammatory tissue damage [ 51 – 53 ]. Characterized as a dual-function regulator, IL6 not only reinforces CD4+ T-cell response by the induced gp130/Jak2/STAT3/NF- κ B signaling cascade but also suppresses the secretion of TNF α and IL1 to attenuate inflammation [ 54 , 55 ].…”