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PIM2 Induced COX-2 and MMP-9 expression in macrophages requires PI3K and Notch1 signaling.

Bansal K, Kapoor N, Narayana Y, Puzo G, Gilleron M, Balaji KN - PLoS ONE (2009)

Bottom Line: PIM2 triggered significant p65 nuclear factor -kappaB (NF-kappaB) nuclear translocation that was dependent on activation of PI3K or Notch1 signaling.Furthermore, COX-2 and MMP-9 expression requires Notch1 mediated recruitment of Suppressor of Hairless (CSL) and NF-kappaB to respective promoters.Inhibition of PIM2 induced COX-2 resulted in marked reduction in MMP-9 expression clearly implicating the role of COX-2 dependent signaling events in driving the MMP-9 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.

ABSTRACT
Activation of inflammatory immune responses during granuloma formation by the host upon infection of mycobacteria is one of the crucial steps that is often associated with tissue remodeling and breakdown of the extracellular matrix. In these complex processes, cyclooxygenase-2 (COX-2) plays a major role in chronic inflammation and matrix metalloproteinase-9 (MMP-9) significantly in tissue remodeling. In this study, we investigated the molecular mechanisms underlying Phosphatidyl-myo-inositol dimannosides (PIM2), an integral component of the mycobacterial envelope, triggered COX-2 and MMP-9 expression in macrophages. PIM2 triggers the activation of Phosphoinositide-3 Kinase (PI3K) and Notch1 signaling leading to COX-2 and MMP-9 expression in a Toll-like receptor 2 (TLR2)-MyD88 dependent manner. Notch1 signaling perturbations data demonstrate the involvement of the cross-talk with members of PI3K and Mitogen activated protein kinase pathway. Enforced expression of the cleaved Notch1 in macrophages induces the expression of COX-2 and MMP-9. PIM2 triggered significant p65 nuclear factor -kappaB (NF-kappaB) nuclear translocation that was dependent on activation of PI3K or Notch1 signaling. Furthermore, COX-2 and MMP-9 expression requires Notch1 mediated recruitment of Suppressor of Hairless (CSL) and NF-kappaB to respective promoters. Inhibition of PIM2 induced COX-2 resulted in marked reduction in MMP-9 expression clearly implicating the role of COX-2 dependent signaling events in driving the MMP-9 expression. Taken together, these data implicate PI3K and Notch1 signaling as obligatory early proximal signaling events during PIM2 induced COX-2 and MMP-9 expression in macrophages.

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TLR2-MyD88 axis plays important role in PIM2 triggered Notch1 activation.(A). TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression as assayed by MMP-9 luciferase reporter activity as described in Materials and Methods. (B). siRNA mediated downregulation of MyD88 in PIM2 triggered nuclear localization of NICD as well as (C). in expression of Notch1 target gene, Hes1, as analyzed by confocal microscopy. (D). RAW 264.7 macrophages were transfected with either vector or dominant-negative TLR2 (TLR2-DN) and Hes1-Luc, followed by treatment with PIM2. The Hes1 promoter activity was evaluated by Luciferase assay. Data presented in the figure is representative of three independent experiments. Med, Medium.
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pone-0004911-g005: TLR2-MyD88 axis plays important role in PIM2 triggered Notch1 activation.(A). TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression as assayed by MMP-9 luciferase reporter activity as described in Materials and Methods. (B). siRNA mediated downregulation of MyD88 in PIM2 triggered nuclear localization of NICD as well as (C). in expression of Notch1 target gene, Hes1, as analyzed by confocal microscopy. (D). RAW 264.7 macrophages were transfected with either vector or dominant-negative TLR2 (TLR2-DN) and Hes1-Luc, followed by treatment with PIM2. The Hes1 promoter activity was evaluated by Luciferase assay. Data presented in the figure is representative of three independent experiments. Med, Medium.

Mentions: Studies have suggested that mycobacteria induced the expression of COX-2 or MMP-9 required the involvement of TLR2 [9] and PIM2 triggered secretion of proinflammatory stimuli such as TNF-α and IL-12 in a TLR2 dependent manner in murine and human macrophages [24]. In this context, when assessed, TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression (Figure 5A) clearly implicating the role of TLR2 in PIM2 mediated activation of signaling events in macrophages. Further, siRNA mediated downregulation of MyD88 expression; a downstream adaptor molecule among majority of TLR signaling pathways, resulted in substantial reduction in PIM2 induced MMP-9 expression (Figure S10).


PIM2 Induced COX-2 and MMP-9 expression in macrophages requires PI3K and Notch1 signaling.

Bansal K, Kapoor N, Narayana Y, Puzo G, Gilleron M, Balaji KN - PLoS ONE (2009)

TLR2-MyD88 axis plays important role in PIM2 triggered Notch1 activation.(A). TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression as assayed by MMP-9 luciferase reporter activity as described in Materials and Methods. (B). siRNA mediated downregulation of MyD88 in PIM2 triggered nuclear localization of NICD as well as (C). in expression of Notch1 target gene, Hes1, as analyzed by confocal microscopy. (D). RAW 264.7 macrophages were transfected with either vector or dominant-negative TLR2 (TLR2-DN) and Hes1-Luc, followed by treatment with PIM2. The Hes1 promoter activity was evaluated by Luciferase assay. Data presented in the figure is representative of three independent experiments. Med, Medium.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2654112&req=5

pone-0004911-g005: TLR2-MyD88 axis plays important role in PIM2 triggered Notch1 activation.(A). TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression as assayed by MMP-9 luciferase reporter activity as described in Materials and Methods. (B). siRNA mediated downregulation of MyD88 in PIM2 triggered nuclear localization of NICD as well as (C). in expression of Notch1 target gene, Hes1, as analyzed by confocal microscopy. (D). RAW 264.7 macrophages were transfected with either vector or dominant-negative TLR2 (TLR2-DN) and Hes1-Luc, followed by treatment with PIM2. The Hes1 promoter activity was evaluated by Luciferase assay. Data presented in the figure is representative of three independent experiments. Med, Medium.
Mentions: Studies have suggested that mycobacteria induced the expression of COX-2 or MMP-9 required the involvement of TLR2 [9] and PIM2 triggered secretion of proinflammatory stimuli such as TNF-α and IL-12 in a TLR2 dependent manner in murine and human macrophages [24]. In this context, when assessed, TLR2 dominant-negative construct significantly reduced PIM2 triggered MMP-9 expression (Figure 5A) clearly implicating the role of TLR2 in PIM2 mediated activation of signaling events in macrophages. Further, siRNA mediated downregulation of MyD88 expression; a downstream adaptor molecule among majority of TLR signaling pathways, resulted in substantial reduction in PIM2 induced MMP-9 expression (Figure S10).

Bottom Line: PIM2 triggered significant p65 nuclear factor -kappaB (NF-kappaB) nuclear translocation that was dependent on activation of PI3K or Notch1 signaling.Furthermore, COX-2 and MMP-9 expression requires Notch1 mediated recruitment of Suppressor of Hairless (CSL) and NF-kappaB to respective promoters.Inhibition of PIM2 induced COX-2 resulted in marked reduction in MMP-9 expression clearly implicating the role of COX-2 dependent signaling events in driving the MMP-9 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.

ABSTRACT
Activation of inflammatory immune responses during granuloma formation by the host upon infection of mycobacteria is one of the crucial steps that is often associated with tissue remodeling and breakdown of the extracellular matrix. In these complex processes, cyclooxygenase-2 (COX-2) plays a major role in chronic inflammation and matrix metalloproteinase-9 (MMP-9) significantly in tissue remodeling. In this study, we investigated the molecular mechanisms underlying Phosphatidyl-myo-inositol dimannosides (PIM2), an integral component of the mycobacterial envelope, triggered COX-2 and MMP-9 expression in macrophages. PIM2 triggers the activation of Phosphoinositide-3 Kinase (PI3K) and Notch1 signaling leading to COX-2 and MMP-9 expression in a Toll-like receptor 2 (TLR2)-MyD88 dependent manner. Notch1 signaling perturbations data demonstrate the involvement of the cross-talk with members of PI3K and Mitogen activated protein kinase pathway. Enforced expression of the cleaved Notch1 in macrophages induces the expression of COX-2 and MMP-9. PIM2 triggered significant p65 nuclear factor -kappaB (NF-kappaB) nuclear translocation that was dependent on activation of PI3K or Notch1 signaling. Furthermore, COX-2 and MMP-9 expression requires Notch1 mediated recruitment of Suppressor of Hairless (CSL) and NF-kappaB to respective promoters. Inhibition of PIM2 induced COX-2 resulted in marked reduction in MMP-9 expression clearly implicating the role of COX-2 dependent signaling events in driving the MMP-9 expression. Taken together, these data implicate PI3K and Notch1 signaling as obligatory early proximal signaling events during PIM2 induced COX-2 and MMP-9 expression in macrophages.

Show MeSH
Related in: MedlinePlus