Showing papers on "Protease-activated receptor 2 published in 2019"
TL;DR: It is shown that duodenal biopsies from patients with active CeD have increased proteolytic activity against gluten substrates that correlates with increased Proteobacteria abundance, including Pseudomonas aeruginosa.
Abstract: Microbe-host interactions are generally homeostatic, but when dysfunctional, they can incite food sensitivities and chronic diseases. Celiac disease (CeD) is a food sensitivity characterized by a breakdown of oral tolerance to gluten proteins in genetically predisposed individuals, although the underlying mechanisms are incompletely understood. Here we show that duodenal biopsies from patients with active CeD have increased proteolytic activity against gluten substrates that correlates with increased Proteobacteria abundance, including Pseudomonas. Using Pseudomonas aeruginosa producing elastase as a model, we show gluten-independent, PAR-2 mediated upregulation of inflammatory pathways in C57BL/6 mice without villus blunting. In mice expressing CeD risk genes, P. aeruginosa elastase synergizes with gluten to induce more severe inflammation that is associated with moderate villus blunting. These results demonstrate that proteases expressed by opportunistic pathogens impact host immune responses that are relevant to the development of food sensitivities, independently of the trigger antigen.
92 citations
TL;DR: It is demonstrated that PAR2 activation–induced M1 polarization and inflammation through the FOXO1‐dependent pathway is demonstrated.
Abstract: Macrophages polarization plays essential but different roles in most diseases such as atherosclerosis, adipose tissue inflammation, and insulin resistance. Our previous study revealed that protease-activated receptor 2 (PAR2), a G-protein coupled receptor influenced macrophage function, but little is known regarding the regulation of macrophage polarization process and its potential mechanisms. In the present study, bone marrow-derived macrophages (BMDM) isolated from C57/BL6 mice and cultured with L929-conditional medium and murine macrophage cell line RAW264.7 were used to study the function of PAR2 activation in vitro. BMDM was stimulated by the small molecular PAR2 agonist, 2-furoyl-LIGRLO-amide trifluoroacetate salt, followed by transcription factor microarray to screen the significantly activated signaling pathways under PAR2 activation. Western blot analysis, quantitative real-time polymerase chain reaction (qRT-PCR) was used to evaluate the expression of targeted genes and transcription factors. Immunofluorescence was used to observe the subcellular distribution of transcription factors. Our results demonstrated that M1-like polarization was presented by PAR2 agonist treatment with significant upregulation of interleukin-1β, interleukin-6, monocyte chemotactic protein-1, and tumor necrosis factor-α in BMDM and RAW264.7. Microarray identified forkhead box protein O1 (FOXO1) was significantly increased under PAR2 agonist stimulation, which was confirmed by qPCR and Western blot analysis. Immunofluorescence demonstrated that increased FOXO1 accumulated in the nucleus, which is necessary to promote transcription for targeted genes. We further knocked down FOXO1 expression using small interfering RNA, which alleviated PAR2-induced proinflammatory gene expression. The PAR2/FOXO1 pathway mediated stimulation of proinflammatory genes was further confirmed by tryptase, an endogenous ligand of PAR2. In conclusion, this study demonstrated that PAR2 activation-induced M1 polarization and inflammation through the FOXO1-dependent pathway.
45 citations
TL;DR: This review discusses the specific roles of one of four mammalian PARs, namely PAR-2, which is overexpressed in advanced stage tumors and is activated by trypsin-like serine proteases that are highly expressed or otherwise dysregulated in many cancers.
Abstract: Pericellular proteolysis provides a significant advantage to developing tumors through the ability to remodel the extracellular matrix, promote cell invasion and migration, and facilitate angiogenesis. Recent advances demonstrate that pericellular proteases can also communicate directly to cells by activation of a unique group of transmembrane G-protein–coupled receptors (GPCR) known as protease-activated receptors (PAR). In this review, we discuss the specific roles of one of four mammalian PARs, namely PAR-2, which is overexpressed in advanced stage tumors and is activated by trypsin-like serine proteases that are highly expressed or otherwise dysregulated in many cancers. We highlight recent insights into the ability of different protease agonists to bias PAR-2 signaling and the newly emerging evidence for an interplay between PAR-2 and membrane-anchored serine proteases, which may co-conspire to promote tumor progression and metastasis. Interfering with these pathways might provide unique opportunities for the development of new mechanism-based strategies for the treatment of advanced and metastatic cancers.
42 citations
TL;DR: Functional protease activated receptor 2 receptors are expressed on both dural afferents and fibroblasts and activation of dural proteaseactivated receptor 2 produces migraine-like behavioral responses, implicating protease activation receptor 2 as a therapeutic target for migraine in humans.
Abstract: BackgroundPain is the most debilitating symptom of migraine. The cause of migraine pain likely requires activation of meningeal nociceptors. Mast cell degranulation, with subsequent meningeal nocic...
40 citations
16 Dec 2019
TL;DR: This work confirmed that PAR2 expression was significantly up-regulated in OA articular cartilage tissues as well as in interleukin 1β stimulated chondrocytes, and found that intra-articular injection of AZ3451 could ameliorate the surgery induced cartilage degradation in rat OA model.
Abstract: Osteoarthritis (OA) is a highly prevalent joint disorder blamed for pain and disability in older individuals. It's commonly accepted that inflammation, apoptosis, autophagy and cellular senescence participate in the progress of OA. Protease activated receptor 2 (PAR2), a member of the G-protein coupled receptors, is involved in the regulation of various inflammation diseases. Previous studies have identified PAR2 as a potential therapeutic target for the treatment of OA. Here, we investigated the role of PAR2 antagonist AZ3451 in inflammation response, apoptosis, autophagy and cellular senescence during OA. We confirmed that PAR2 expression was significantly up-regulated in OA articular cartilage tissues as well as in interleukin 1β (IL-1β) stimulated chondrocytes. We demonstrated AZ3451 could prevent the IL-1β-induced inflammation response, cartilage degradation and premature senescence in chondrocytes. Further study showed that AZ3451 attenuated chondrocytes apoptosis by activating autophagy in vitro. The P38/MAPK, NF-κB and PI3K/AKT/mTOR pathways were involved in the protective effect of AZ3451. In vivo, we found that intra-articular injection of AZ3451 could ameliorate the surgery induced cartilage degradation in rat OA model. Our work provided a better understanding of the mechanism of PAR2 in OA, and indicated that PAR2 antagonist AZ3451 might serve as a promising strategy for OA treatment.
31 citations
TL;DR: Findings indicate that rivaroxaban exerts protective effects against angiotensin II–induced renal damage, partly through inhibition of the PAR‐2 signaling‐mediated inflammatory response.
Abstract: Background An enhanced renin‐angiotensin system causes hypertensive renal damage. Factor Xa not only functions in the coagulation cascade but also activates intracellular signaling through protease...
31 citations
TL;DR: Intradermal injection of cathepsin S induces scratching behaviour in mice and acts as a pruritogen via protease-activated receptor 2(PAR2) in TRPV1-expressing neurons, which can be used as translational model and for testing new indications for cathePSin S inhibitors.
22 citations
TL;DR: PGE2-EP2 signaling negatively regulates murine AD-like skin inflammation by suppressing TSLP expression and promoting type 2 immune responses in the skin.
Abstract: Background Atopic dermatitis (AD) is a common and chronic inflammatory skin disease of type 2 immunity Keratinocyte-derived cytokines, including thymic stromal lymphopoietin (TSLP) and IL-33, are considered to induce the development of AD Production of prostanoids, a family of lipid mediators, is increased in AD lesions However, their physiologic functions remain to be clarified Objectives We sought to elucidate the functions of prostanoids in the development of AD Methods The roles of prostanoids were investigated in a mouse model of AD induced by repeated application of hapten and PAM212, a keratinocyte cell line Results Application of indomethacin, which blocks prostanoid synthesis, leads to enhanced TSLP and IL-33 production in the skin, increased serum IgE levels, and exacerbation of skin inflammation in this AD model The skin inflammation was attenuated in TSLP receptor–deficient mice but not in IL-33–deficient mice, and the indomethacin-enhanced type 2 immune responses were abolished in TSLP receptor–deficient mice Indomethacin increased protease-activated receptor 2–mediated TSLP production in keratinocytes in vitro, and prostaglandin E2 reversed the increase in TSLP levels through its receptor, the prostaglandin E2 receptor (EP2), by downregulating surface expression of protease-activated receptor 2 Administration of an EP2 agonist canceled indomethacin-enhanced TSLP production and type 2 immune responses in the skin, whereas an EP2 antagonist caused an enhancement of TSLP production and type 2 immune responses in the skin Conclusion Prostaglandin E2–EP2 signaling negatively regulates murine AD-like skin inflammation by suppressing TSLP expression
22 citations
TL;DR: Thymic stromal lymphopoietin mediates proallergic T helper 2‐type responses by acting on leucocytes and endogenous pathways regulating TSLP production are poorly defined.
Abstract: Background Thymic stromal lymphopoietin (TSLP) mediates proallergic T helper 2-type responses by acting on leucocytes. Endogenous pathways regulating TSLP production are poorly defined. Objectives To uncover the mechanisms by which skin barrier disruption elicits TSLP production and to delineate the level at which individual mechanistic components may converge. Methods A combination of primary keratinocytes, skin explants and in vivo strategies was employed. Murine skin was tape stripped in the presence of neutralizing antibodies or antagonists. Cells and explants were stimulated with interleukin (IL)-1 and protease-activated receptor 2 agonist (PAR-2-Ag). TSLP levels were quantified by enzyme-linked immunosorbent assay and real-time quantitative polymerase chain reaction. Chromatin immunoprecipitation and promoter reporter assays were used to examine recruitment and functional activity of nuclear factor kappa B (NF-κB) at the TSLP promoter. Results TSLP induction in mouse skin occurred in a PAR-2- and IL-1-dependent manner. This scenario was duplicated by exogenous IL-1 plus PAR-2-Ag vs. each stimulus alone. Joint activity of PAR-2 and IL-1 was also observed in human keratinocytes. The TSLP promoter was identified as the target of PAR-2/IL-1, whereby PAR-2 activation augmented the recruitment of NF-κB and transcriptional activation over IL-1 alone. Combined treatment showed activity at concentrations of IL-1 unable to elicit NF-κB activity on their own. Conclusions Skin barrier disruption activates the IL-1 and the PAR-2 pathways, which act in concert to activate the TSLP promoter and possibly other inflammatory genes. Awareness of this combined activity may permit a more flexible clinical management by selective targeting of either pathway individually or collectively. What's already known about this topic? Thymic stromal lymphopoietin (TSLP) is rapidly induced upon skin perturbation and mediates proallergic T helper 2-type responses by acting on leucocytes. Endogenous control of TSLP expression is poorly understood, but interleukin (IL)-1 is one regulator in the cutaneous environment In addition to IL-1, protease-activated receptor 2 (PAR-2) organizes central inflammatory pathways in the skin. What does this study add? IL-1 and PAR-2 pathways cooperate in driving TSLP production in mice and humans. Pathway integration occurs at the level of the TSLP promoter through enhanced recruitment and transcriptional activation of nuclear factor kappa B. When PAR-2 is co-stimulated, very low IL-1 levels (inactive by themselves) can induce biologically meaningful responses in the skin environment. What is the translational message? Physical skin irritation results in robust TSLP production by simultaneous activation of PAR-2 and IL-1 pathways.
18 citations
TL;DR: A novel concept is provided of how thrombin efficiently cleaves PAR2 in a TM co-receptor-dependent manner, resulting in pro-inflammatory interleukin-8 release and may lead to novel therapeutic options for treating inflammatory and malignant diseases.
18 citations
TL;DR: The current knowledge on the cooperation between PAR2 and TLR4 is summarized, the potential cross-talk levels are discussed and the impact of the cross-coupling on neuroinflammation is highlighted.
TL;DR: It is proposed that acute exposure to HDM allergens activate AECs at a very early stage where PAR-2/IL-17R signaling serves a crucial role in neutrophilic inflammation.
TL;DR: PAR2 regulates migration through β-arrestin 1-dependent activation of p38 MAPK and EMT through ERK2-mediated stabilization of Slug in lung adenocarcinoma cells, suggesting that PAR2 might serve as a therapeutic target for metastatic lung cancer and a potential biomarker for predicting the prognosis of lung cancer.
TL;DR: Elevated PAR2 exacerbates cisplatin nephrotoxicity, and targeting PAR2 is a novel therapeutic option that aids in the treatment of patients with cis platin-induced AKI.
Abstract: Acute kidney injury (AKI) is associated with hypercoagulability. Tissue factor/factor VIIa complex and factor Xa in the coagulation cascade activate protease-activated receptor 2 (PAR2). Previously...
TL;DR: ROS generation and epidermal tight junction degradation are triggered by protease, followed by the induction of TSLP in allergic asthma, which could suggest that PAR2-ant or anti-oxidants could be considered for allergic diseases as preventive alternatives.
Abstract: Purpose Protease-activated receptor 2 (PAR2) reportedly triggers the immune response in allergic asthma. We aimed to investigate the mechanism on allergic inflammation mediated by PAR2. Methods Human lung epithelial cells (A549 cells) were used for in vitro, and the German cockroach extract (GCE)-induced mouse model was developed for in vivo studies. Results In A549 cells, the levels of reactive oxygen species (ROS) and thymic stromal lymphopoietin (TSLP) were significantly increased by GCE treatment, but were suppressed by PAR2-antagonist (PAR2-ant) or N-acetylcysteine (NAC) treatment. Claudin-1 was degraded by GCE, and was restored by PAR2-ant or NAC in the cells. In the mouse model, the clinical appearance including bronchial hyperresponsiveness, bronchoalveolar lavage fluid analysis and total immunoglobulin E were significantly suppressed by PAR2-ant or NAC. Moreover, TSLP levels in the lung were suppressed by the same treatments in the lung. Claudin-1 was also degraded by GCE, and was restored by PAR2-ant or NAC. Conclusions ROS generation and epidermal tight junction degradation are triggered by protease, followed by the induction of TSLP in allergic asthma. Our findings could suggest that PAR2-ant or anti-oxidants could be considered for allergic diseases as preventive alternatives.
TL;DR: HSV1 surface TF facilitated infection of all organs evaluated and anticoagulants were antiviral and protease activated receptor 2 inhibited infection in vivo and its pre‐activation was antiviral.
TL;DR: The objectives of this study were to determine the specific fungal component(s) and the receptor responsible for mediating the A. fumigatus induced increase in IL‐33 expression in SNECs from patients with CRSwNP.
Abstract: Objective: In the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP), Aspergillus fumigatus (A. fumigatus) can upregulate IL-33 from human sinonasal epithelial cells (SNECs), which then activates innate lymphoid cells causing release of IL-13, an important driver of allergic inflammation. However, the mechanism by which A. fumigatus mediates the induction of IL-33 expression remains to be elucidated. The objectives of this study were to determine the specific fungal component(s) and the receptor responsible for mediating the A. fumigatus induced increase in IL-33 expression in SNECs from patients with CRSwNP.
Methods: SNECs from CRSwNP patients were cultured and stimulated with various fungal components in the absence or presence of 4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride, an irreversible serine protease inhibitor, or GB83, a reversible protease activated receptor 2 (PAR2) inhibitor. IL-33 expression was evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). PAR2 expression was examined in inflamed mucosa from nonatopic control and CRSwNP patients.
Results: Elevation of IL-33 expression in primary SNECs was found in response to fungal protease but not fungal cell wall components. PAR2 expression was elevated in inflamed mucosa from CRSwNP patients in comparison to controls. The A. fumigatus fungal protease-mediated elevation in IL-33 expression by human SNECs was serine protease- and PAR2-dependent.
Conclusion: These data suggest that serine protease activity of A. fumigatus is capable of inducing IL-33 expression in CRSwNP SNECs via PAR2, a potential therapeutic target in the treatment of CRSwNP.
Level of evidence: NA Laryngoscope, 129:2230-2235, 2019.
TL;DR: PAR2 promotes cell proliferation and disrupts the quiescent condition of VSMCs, which may be a potential therapeutic target for atherosclerosis.
Abstract: BACKGROUND Protease-Activated Receptor 2 (PAR2), a G-protein-coupled receptor, has been proved to be enhanced in human coronary atherosclerosis lesions. We aimed to investigate whether PAR2 actively participates in the atherosclerosis process. MATERIAL AND METHODS PAR2 expression was assessed in blood samples by RT-qPCR from healthy controls and patients with atherosclerosis. Human vascular smooth muscle cells (VSMCs) were treated with oxidative low-density lipoprotein (ox-LDL). After PAR2 overexpression by transfection, cell proliferation was determined by CCK-8, and cell migration was evaluated by Transwell assay. The protein expressions associated with cell growth and migration were measured by Western blot. The distribution of alpha-SMA in VSMCs was evaluated by immunofluorescence. RESULTS Expression of PAR2 was higher in patients with atherosclerosis compared with normal controls. PAR2 mRNA and protein expression was increased in ox-LDL-treated VSMCs compared with control cells. Induced overexpression of PAR2 in VSMCs led to a reduction in alpha-SMA expression compared to controls. In addition, PAR2 overexpression caused increased migration compared to normal controls, and upregulated MMP9 and MMP14 expression. PAR-2 overexpression promoted cell proliferation compared to control cells, and increased expression levels of CDK2, and CyclinE1, but reduced levels of p27. We preliminary explored the potential mechanism of PAR2, and results showed that overexpression of PAR2 increased expression levels of VEGFA and Angiopoietin 2 compared to controls. Moreover, overexpression of PAR2 enhanced production of tissue factor and IL-8 compared to normal controls. CONCLUSIONS PAR2 promotes cell proliferation and disrupts the quiescent condition of VSMCs, which may be a potential therapeutic target for atherosclerosis.
TL;DR: The results suggest that PAR2 is protective against VEGF inhibitor-induced glomerular endothelial and podocyte injury and administration of an anti-VEGF antibody in mice lacking PAR2 and eNOS exacerbated albuminuria and reduced the expression levels of CD31, pro-angiogenic VEGf, and angiogenesis-related chemokines in their kidneys.
Abstract: Vascular endothelial growth factor (VEGF) inhibitors cause glomerular injury. We have recently shown that activation of protease-activated receptor 2 (PAR2) by factor Xa exacerbated diabetic kidney disease. However, the role of PAR2 in glomerular injury induced by VEGF blockade is not known. Herein, we investigated the effect of the lack of PAR2 on VEGF inhibitor-induced glomerular injury. Although administering an anti-VEGF antibody by itself did not show renal phenotype in wild type mice, its administration to mice lacking endothelial nitric oxide synthase (eNOS) caused glomerular injury. Different from what we expected, administration of an anti-VEGF antibody in mice lacking PAR2 and eNOS exacerbated albuminuria and reduced the expression levels of CD31, pro-angiogenic VEGF, and angiogenesis-related chemokines in their kidneys. Podocyte injury was also evident in this model of mice lacking PAR2. Our results suggest that PAR2 is protective against VEGF inhibitor-induced glomerular endothelial and podocyte injury.
Journal Article•
TL;DR: It was found that the expression of protease activated receptor 2 (PAR2) was highly correlated with that of MYO10 in colorectal carcinoma (CRC) specimens and both myO10 and PAR2 were up-regulated in lymph node metastasis group compared with non-metastasis group.
Abstract: MYO10 is an actin-based motor protein and correlates with cancer metastasis. However, the regulation of MYO10 by tumor microenvironment is unknown. In the current study, we found that the expression of protease activated receptor 2 (PAR2) was highly correlated with that of MYO10 in colorectal carcinoma (CRC) specimens. Both MYO10 and PAR2 were up-regulated in lymph node metastasis group compared with non-metastasis group. Activation of PAR2 significantly induced cell migration through the up-regulation of MYO10, which was mediated by repression of miR-204 in multiple cell lines. Interestingly, it was observed that tryptase was highly expressed in adjacent tissue around primary tumor of CRC. Furthermore, tryptase stimulated cell migration and up-regulated MYO10 expression through a PAR2-dependent manner. Taken together, our findings showed that PAR2 enhanced the expression of MYO10 through the repression of miR-204. PAR2 mediated tryptase-induced cell migration and might contribute to the invasion of cancer cells at the edge of tumor.
TL;DR: Stress‑induced esophageal inflammation and ROS generation involves VH, and stress markedly reduced antioxidant expression, while it significantly upregulated TRPV‑1 and PAR‑2 expression levels in the mouse esophagus.
Abstract: Stress is a pivotal factor for inflammation, reactive oxygen species (ROS) production and formation of visceral hypersensitivity (VH) in the process of gastroesophageal reflux disease (GERD). In the present study, the effects of stress on esophageal inflammation, oxidative stress and VH were investigated in a chronic restraint stress mouse model. C57BL/6J male mice were subjected to 2 weeks of intermittent restraint stress, and histopathological analysis revealed that stress induced esophageal inflammation and fibrosis, while no distinct changes were detected in non‑stressed control mice. In addition, increased NADPH oxidase 4 expression was observed in the plasma and esophagus of stressed mice, indicating accumulation of ROS. The expression levels of antioxidants, including Mn‑superoxide dismutase (MnSOD), Cu/Zn‑SOD, catalase and glutathione peroxidase, were also analyzed using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). In addition, transient receptor potential vanilloid 1 (TRPV‑1) and protease‑activated receptor 2 (PAR‑2), which are crucial receptors for VH, were measured by immunohistochemistry and RT‑qPCR. The results demonstrated that stress markedly reduced antioxidant expression, while it significantly upregulated TRPV‑1 and PAR‑2 expression levels in the mouse esophagus. Finally, 2 weeks of restraint stress significantly increased the esophageal and plasma levels of inflammatory cytokines, including interleukin (IL)‑6, IL‑8, interferon‑γ and tumor necrosis factor‑α. Taken together, the present study results indicated that stress‑induced esophageal inflammation and ROS generation involves VH.
TL;DR: The results indicate that HAT stimulates IL-8 synthesis in airway epithelial cells via PAR2 and could help to amplify inflammation in chronic respiratory tract disease.
TL;DR: It is found that proteases that activate PAR2 by canonical and biased mechanisms stimulate PKD in the Golgi; PAR2 mobilization and de novo synthesis repopulate the cell surface with intact receptors and sustain nociceptive signaling by extracellular proteases.
TL;DR: FS inhibited cervical cancer by reducing proliferation and inducing apoptosis by interfering with STAT-3 signaling.
Abstract: ObjectiveThe present study explored how the inhibition of protease-activated receptor-2 (PAR-2) induced proliferation and apoptosis in cervical cancer in vitro and in vivo.MethodsmRNA and protein e...
TL;DR: It is suggested that PAR2, possibly via 12-LOX, activates TRPV1 and leads to CGRP and substance P release to prevent I/R injury in the heart, indicating that the 12- LOX-TRPV 1 pathway conveys cardiac protection to alleviate myocardial infarction.
Abstract: This study tests the hypothesis that the lipoxygenase (LOX) pathway mediates protease-activated receptor (PAR) 2-induced activation of the transient receptor potential vanilloid receptor 1 (TRPV1) to protect the heart from ischemia/reperfusion (I/R) injury. SLIGRL, a PAR2 activating peptide, was administered prior to reperfusion following left anterior descending coronary artery ligation in wild type (WT) and TRPV1 knockout (TRPV1-/-) mice. In a Langendorffly perfused heart I/R model, hemodynamic parameters, including left ventricular end-diastolic pressure, left ventricular developed pressure, coronary blood flow and left ventricular peak +dP/dt were evaluated after I/R. SLIGRL reduced the cardiac infarct size in WT and TRPV1-/- mice with a greater effect in the former strain (P<0.05). SLIGRL increased plasma levels of calcitonin gene-related peptide (CGRP) and substance P in WT (both P<0.05) but not in TRPV1-/- mice. Pretreatment with CGRP8-37 (a CGRP receptor antagonist) or RP67580 (a neurokinin-1 receptor antagonist) alone had no effect on SLIGRL-induced cardiac protection in either strain. However, combined administration of CGRP8-37 and RP67580 abolished SLIGRL-induced cardiac protection in WT but not in TRPV1-/- mice. Nordihydroguaiaretic acid (a general LOX inhibitor) and baicalein (a 12-LOX inhibitor), but not indomethacin (a cyclooxygenase inhibitor) and hexanamide (a selective cytochrome P450 epoxygenase inhibitor), abolished the protective effects of SLIGRL in WT (all P<0.05) but not in TRPV1-/- hearts. These data suggested that PAR2, possibly via 12-LOX, activates TRPV1 and leads to CGRP and substance P release to prevent I/R injury in the heart, indicating that the 12-LOX-TRPV1 pathway conveys cardiac protection to alleviate myocardial infarction.
01 Apr 2019
TL;DR: The data suggest that, PAR2 activation and subsequent Ca2+ entry through CRAC channels are important mechanisms in prostate smooth muscle contraction.
Abstract: Protease activated receptor 2 (PAR2) is a G-protein coupled receptor that contributes to prostate fibrosis and lower urinary tract symptoms (LUTS). In addition to fibrosis, aberrant smooth muscle tone in the prostate has been hypothesized to play a role. We therefore examined PAR2 expression in primary human prostate smooth muscle cells (PSMC) and studied the downstream signaling effects of PAR2 activation. Signaling pathways involved in the process were assessed using the PAR2 activating peptide SLIGKV-NH2. We show that PAR2 is expressed in PSMC and that PAR2 activation mediates a biphasic elevation in intracellular Ca2+ and phosphorylation of myosin light chain 20 (MLC20), causing cellular contraction as assessed in a gel contraction assay. Intracellular Ca2+ flux was inhibited by a phosphoinositide hydrolysis inhibitor, U73122, showing a requirement for phospholipase C β (PLCβ) activation. PSMC expressed mRNA for L-type voltage dependent Ca2+ channels (VDCC) as well as Ca2+ release activated channels (CRAC), a hitherto unreported finding. Secondary intracellular Ca2+ oscillations were abrogated only by BTP2, the CRAC channel inhibitor, but not by nifedipine, an inhibitor of VDCC. These data suggest that, PAR2 activation and subsequent Ca2+ entry through CRAC channels are important mechanisms in prostate smooth muscle contraction.
TL;DR: Results suggest that inhibition of PAR2 may increase the severity of inflammation in lupus nephritis; namely, opposite to previous observations, PAR2 has anti-inflammatory properties.
Abstract: Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies, which causes multi-organ injury such as lupus nephritis. SLE is associated with hypercoagulability. Activated coagulation factors such as tissue factor and VIIa complex and factor Xa activate protease-activated receptor 2 (PAR2). PAR2 promotes cytokine production through mitogen-activated protein kinase or nuclear factor kappa B signaling, and previous reports demonstrated that inhibition of PAR2 alleviated kidney injuries such as diabetic kidney disease and renal fibrosis in animal models. However, the involvement of PAR2 in the pathogenesis of SLE remains unclear. We therefore administered a selective PAR2 peptide antagonist, FSLLRY-NH2, to SLE-prone 4-month-old MRL-Faslpr mice for 4 weeks. Treatment with FSLLRY-NH2 caused the significant increases in the glomerular mesangial proliferation, glomerular deposition of both immunoglobulin G and complement factor C3d, and glomerular infiltration of Mac2-positive macrophages and CD3-positive T cells, compared with MRL-Faslpr mice treated with saline. In addition, the treatment with the PAR2 antagonist increased renal expression levels of tumor necrosis factor-α (Tnfa) and monocyte chemoattractant protein 1 (Mcp1) mRNA. Collectively, these results suggest that inhibition of PAR2 may increase the severity of inflammation in lupus nephritis; namely, opposite to previous observations, PAR2 has anti-inflammatory properties. We propose that activation of PAR2 could serve as a potential therapeutic option for patients with SLE.
Journal Article•
TL;DR: In this paper, the authors show that Vascular smooth muscle cells are an abundant source of protease-activated receptor 2 (PAR2) in the aortic media, and that PAR2 signaling promotes the release of pr...
Abstract: Background: Vascular smooth muscle cells are an abundant source of protease-activated receptor 2 (PAR2) in the aortic media. Accumulating evidence suggests PAR2 signaling promotes the release of pr...
TL;DR: A novel concept is provided of how thrombin efficiently cleaves PAR2 in a TM co-receptor-dependent manner, resulting in pro-inflammatory interleukin-8 release and may lead to novel therapeutic options for treating inflammatory and malignant diseases.
Abstract: Introduction Protease-activated receptors (PARs) evolved to react to extracellular proteolytic activity. In mammals, three of the four PARs (PAR1, PAR3, and PAR4) that are expressed respond to the prototypical procoagulant enzyme thrombin, whereas PAR2 was assumed to resist activation by thrombin. To date, involvement of cell surface thrombin-recruiting co-receptors such as thrombomodulin (TM), which potentially facilitates PAR2 cleavage, has not been addressed. Thus, we examined whether TM-bound thrombin cleaved PAR2 and tested biological responses such as nuclear factor kappa B (NF-κB) DNA binding activity and cytokine release. Materials and Methods We examined 293T cells overexpressing PAR2 and TM for thrombin recruitment by TM promoting PAR2 cleavage. To test for the TM–thrombin interactions required for PAR2 cleavage and to map cleavage sites on PAR2, mutant constructs of TM or PAR2 were engineered. Biological effects because of PAR2 activation were investigated using an NF-κB reporter system and cytokine release. Results and Conclusions We identified that, at low to moderate concentrations, thrombin cleaved PAR2 in a TM co-receptor-dependent manner with cleavage efficiency comparable to that of trypsin. In TM’s presence, thrombin efficiently cleaved both, PAR1 and PAR2, albeit kinetics differed. Whereas the majority of surface expressed PAR1 was immediately cleaved off, prolonged exposure to thrombin resulted in few additional cleavage. In contrast, PAR2 cleavage was sustained upon prolonged exposure to thrombin. However, TM EGF-like domain 5 was required and TM chondroitin sulfate (CS) proteoglycan sites serine 490 and serine 492 assisted in PAR2 cleavage, while thrombin preferentially cleaved at arginine 36 on PAR2’s N-terminus. Note that thrombin-induced activation of NF-κB via PAR2 resulted in release of interleukin-8. Thus, we provide a novel concept of how thrombin efficiently cleaves PAR2 in a TM-dependent manner, resulting in pro-inflammatory interleukin-8 release. This unexpected pro-inflammatory role of TM, promoting cleavage and activation of PAR2 by thrombin, may lead to novel therapeutic options for treating inflammatory and malignant diseases.