TLR2 and AP-1/NF-kappaB are involved in the regulation of MMP-9 elicited by heat killed Listeria monocytogenes in human monocytic THP-1 cells

Abstract

BackgroundMMP-9 is crucial for a normal immune response, but excessive release of this enzyme leads to severe tissue damage. Listeria monocytogenes (LM) is an opportunistic food-borne pathogen causing listerosis, meningitis and sepsis. Heat killed Listeria monocytogenes (HKLM) activates immune system and leads production of cytokines and chemokines. However, nothing is known about the involvement of HKLM in MMP-9 regulation. Therefore we investigated the role of HKLM in the regulation of MMP-9 gene expression in THP-1 cells.MethodsCommercially available heat killed Listeria monocytogenes was used in this study. HKLM-induced MMP-9 expression was assessed with quantitative real-time qPCR and ELISA. Action of HKLM in different signaling pathways were studied by using THP-1-XBlue™ cells (THP-1-cells with NF-κB/AP-1 reporter construct), THP-1-XBlue™-defMyD cells (MyD88−/− THP-1 cells), anti-TLR2 mAb and pharmacological inhibitors. Phospho and total proteins were determined by Western blotting.ResultsIncreased MMP-9 production (mRNA: 395-Fold; Protein: 8141 pg/ml; P < 0.05) was observed in HKLM stimulated THP-1 cells as compared to the un-stimulated THP-1 cells. This production of MMP-9 was completely abrogated by anti-TLR2 blocking mAb (P = 0.0024). Furthermore, THP-1-XBlue™-defMyD cells were unable to produce MMP-9 in response to HKLM. HKLM- induced activation of NF-kappaB/AP-1 was also observed in THP-1-XBlue™ Cells. In addition, inhibitors of JNK (SP600125), MEK/ERK (U0126; PD98056), p38 MAPK (SB203580) and NF-kappaB (BAY 11–7085, Triptolide and Resveratrol) significantly suppressed (P < 0.05) HKLM-stimulated MMP-9 expression.ConclusionOur results indicate that HKLM activates TLR2 and NF-κB/AP-1 signaling pathways, leading to up-regulation of MMP-9 production in THP-1 cells. Thus, MMP-9 could be an appropriate therapeutic target to stop severe tissue damage caused by infection or chronic inflammation.

Pam3CSK4 Induces MMP-9 Expression in Human Monocytic THP-1 Cells

“…Bacterial components such as LPS, lipopeptides, lipoteichoic acids (LTAs), and peptidoglycan stimulate the production of cytokines and other inflammatory mediators [35,36]. FSL-1 and HKLM were reported to induce MMP-9 production [23,24,37]. Herein, we show that Pam3CSK4 induces MMP-9 production in monocytic cells.…”

“…In obesity, MMP-9 may facilitate the infiltration of immune cells into the adipose tissue and could promote obesity-associated metabolic inflammation. We earlier showed that microbial components and the free fatty acid palmitate induced robust MMP-9 production in monocytic cells [19,24]. Bacterial lipoprotein were shown to induce inflammatory mediators including IL-6, TNF-α, IL-8, CSF2, CSF3, and ICAM1and IL-1β [32].…”

Palmitate-Induced MMP-9 Expression in the Human Monocytic Cells is Mediated through the TLR4-MyD88 Dependent Mechanism

“…THP-1-XBlue™-defMyD cells were cultured in complete RPMI medium with the addition of Zeocin (200 ug/ml) and HygroGold (100 ug/ml) (InvivoGen, San Diego, CA, USA). Prior to stimulation, THP-1 cells were transferred into normal medium and plated in 12-well plates (Costar, Corning Incorporated, Corning, NY, USA) at 1 × 10 6 cells/well cell density unless indicated otherwise [26].…”

MMP2 and MMP9 are Associated with Apical Periodontitis Progression and Might be Modulated by TLR2 and MyD88

“…TLR2 up-regulates MMP2 and MMP9 in glioma stem cells (18) and up-regulates MMP9 in monocytic cells (19). Although the interaction between these proteins has been previously investigated, their role in AP progression is still unexplored.…”