Protease-Activated Receptor 2 Mediates Human Beta-Defensin 2 and CC Chemokine Ligand 20 mRNA Expression in Response to Proteases Secreted byPorphyromonas gingivalis

Abstract

The oral pathogen Porphyromonas gingivalis secretes proteases such as Arg-gingipain B (RgpB) that activate protease-activated receptors (PARs). Human beta-defensins (hBDs) and the macrophage inflammatory protein 3␣/CC chemokine ligand 20 (CCL20) produced by epithelial cells are antimicrobial peptides that provide cytokine function and play an important role in innate immunity. The aim of the present study was to determine whether specific members of the PAR family mediate the expression of these innate immunity markers in gingival epithelial cells (GECs) when exposed to P. gingivalis cell-free culture supernatant or purified RgpB. hBD-2 mRNA in GECs was induced in response to supernatant and purified RgpB from P. gingivalis (P ‫؍‬ 0.02 and P ‫؍‬ 0.016, respectively). This effect was abrogated by the protease inhibitor tosyl-Llysine chloromethyl ketone (TLCK) (P < 0.05). In response to P. gingivalis supernatant and to purified RgpB, the hBD-2 mRNA expression was significantly decreased in PAR-2 gene knockdown cells, whereas no change was detected in PAR-1 gene knockdown cells. CCL20 mRNA expression also increased in response to the supernatant of P. gingivalis, and this effect was blocked by the protease inhibitor, TLCK (P ‫؍‬ 0.05 and P ‫؍‬ 0.024, respectively), and was blocked in PAR-2 gene knockdown cells. Our data indicate that hBD-2 and CCL20 mRNA up-regulation by P. gingivalis supernatant and purified RgpB was mediated via PAR-2, but not via PAR-1, and that proteases play a role in the regulation of innate immune responses in GECs. GECs use PARs to recognize P. gingivalis and mediate cell responses involved in innate immunity.

Mucosal Allergic Sensitization to Cockroach Allergens Is Dependent on Proteinase Activity and Proteinase-Activated Receptor-2 Activation

“…We (41) and others (42) also have shown that PAR 2 activation of the epithelium leads to the release of GM-CSF, which has the potential to activate dendritic cells. PAR 2 activation also induces CCL20 release (43), which through activation of CCR6 can attract immature dendritic cells to mucosal surfaces (44). Each one of these pathways may be important for the development of allergic sensitization to cockroach allergens through PAR 2 activation.…”

Fusobacterium nucleatum-associated β-Defensin Inducer (FAD-I)

“…In addition, our ELISA data suggest that hBD2 is degraded upon release by P. gingivalis-associated proteases, whereas it is produced significantly above base line by F. nucleatum. Dommisch et al (60) indicated that the low level induction of hBD2 mRNA is due to P. gingivalis activation of protease-activated receptor 2 (PAR-2). Interestingly, PAR-2 was recently shown to activate stressactivated protein kinase (61), suggesting that severe stress may be related to the low level induction of hBD2 by P. gingivalis.…”

Isoleucine, an Essential Amino Acid, Induces the Expression of Human &lt;i&gt;β&lt;/i&gt; Defensin 2 through the Activation of the G-Protein Coupled Receptor-ERK Pathway in the Intestinal Epithelia

“…Many types of GPCRs, such as taste receptor and GPR35, are expressed in the intestinal epithelia [18][19][20]. In addi- tion, the functions of some GPCRs are associated with the expression of anti-microbial peptides in neutrophils and gingival cells [21,22]. Furthermore, an α subunit of the GPCRs, Gi, is known to be involved in the activation of the ERK signaling pathway [23][24][25][26][27][28][29], suggesting a possibility that GPCRs are involved in the induction of HBD2 mRNA by Ile in the intestinal epithelia.…”