The expression and significance of protease activated receptor 2 in ovarian epithelial carcinoma / 中华肿瘤杂志

Objective: To investigate the expression and significance of protease activated receptor 2 (PAR2) in ovarian epithelial carcinoma. Methods: PAR2 mRNA expression levels in 410 cases of epithelial ovarian carcinoma and 88 cases of human normal ovary were analyzed from cancer Genome Atlas (TCGA) database and tissue genotypic expression database (GTEx). Immunohistochemical (IHC) staining of PAR2 protein was performed in 149 patients with ovarian cancer who underwent primary surgical treatment at Cancer Hospital of Chinese Academy of Medical Sciences. Then the relationship between mRNA/protein expression of PAR2 and clinicopathological features and prognosis was analyzed. Gene functions and related signaling pathways involved in PAR2 were studied by enrichment analysis. Results: The mRNA expression of PAR2 in epithelial ovarian carcinoma was significantly higher than that in normal ovarian tissue (3.05±0.72 vs. 0.33±0.16, P=0.004). There were 77 cases showing positive and 19 showing strong positive of PAR2 IHC staining among the 149 patients, accounting for 64.4% in total. PAR2 mRNA/protein expression was closely correlated with tumor reduction effect and initial therapeutic effect (P<0.05). Survival analysis showed that the progression free survival time (P=0.033) and overall survival time (P=0.011) in the group with high PAR2 mRNA expression was significantly lower than that in the low PAR2 mRNA group. Multivariate analysis showed tumor reduction effect, initial therapeutic effect were independent prognostic factors on both progression-free survival and overall survival (P<0.05). The progression-free survival (P=0.016) and overall survival (P=0.038) of the PAR2 protein high expression group was significantly lower than that of the low group. Multivariate analysis showed PAR2 expression, initial treatment effect and chemotherapy resistance were independent prognostic factors on both progression-free survival and overall survival (P<0.05). Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), PAR2 target genes were mainly enriched in function related to intercellular connection, accounting for 40%. Gene enrichment analysis (GSEA) showed that the Wnt/β-catenin signaling pathway (P=0.023), the MAPK signaling pathway (P=0.029) and glycolysis related pathway (P=0.018) were enriched in ovarian cancer patients with high PAR2 mRNA expression. Conclusions: PAR2 expression is closely related to tumor reduction effect, initial treatment effect and survival of ovarian cancer patients. PAR2 may be involved in Wnt/β-catenin signaling pathway and intercellular connection promoting ovarian cancer invasion and metastasis.

Pharmacological blockade of protease-Activated Receptor 2 improves airway remodeling and lung inflammation in experimental allergic asthma

Abstract Protease-activated receptors (PARs) are metabotropic G-protein-coupled receptors that are activated via proteolytic cleavage of a specific sequence of amino acids in their N-terminal region. PAR2 has been implicated in mediating allergic airway inflammation. This study aims to study the effect of PAR2 antagonist ENMD1068in lung inflammation and airway remodeling in experimental asthma. Allergic lung inflammation was induced in sensitized BALB/c mice through intranasal instillations of ovalbumin (OVA), and mice were pretreated with ENMD1068 1 hour before each OVA challenge. Bronchoalveolar lavage fluid (BALF) was collected, and the lungs were removed at different time intervals after OVA challenge to analyze inflammation, airway remodeling and airway hyperresponsiveness. Ovalbumin promoted leukocyte infiltration into BALF in a PAR2-dependent manner. ENMD1068 impaired eosinophil peroxidase (EPO) and myeloperoxidase (MPO) activity in the lung parenchyma into BALF and reduced the loss of dynamic pulmonary compliance, lung resistance in response to methacholine, mucus production, collagen deposition and chemokine (C-C motif) ligand 5 expression compared to those in OVA-challenged mice. We propose that proteases released after an allergen challenge may be crucial to the development of allergic asthma in mice, and PAR2 blockade may be useful as a new pharmacological approach for the treatment of airway allergic diseases.

Effect of protease activated receptor 2 on colonic motility in diabetes mice / 上海交通大学学报（医学版）

Objective • To observe the effect of protease activated receptor 2 (PAR2) on the colonic motility in diabetic mice and investigate the mechanism. Methods • The mouse model of type 1 diabetes mellitus was established by intraperitoneal injection of streptozotocin. The smooth muscle strips and segments of colons were isolated. The effects of PAR2 agonist on colonic motility were observed by muscle strip tension contraction and colonic migrating motor complex experiments. The effect of small conductance calcium-activated potassium channel (SK3 channel) antagonist on it was also observed. Results • PAR2 agonist inhibited colonic motility and colonic smooth muscle was more sensitive to PAR2 agonist in diabetic mice. PAR2 agonist-induced inhibition was inhibited by SK3 channel antagonist. Conclusion • PAR2 activity in diabetic mice colons is significantly enhanced, which may inhibit colonic motility through SK3 channel.

Protease-Activated Receptors 2-Antagonist Suppresses Asthma by Inhibiting Reactive Oxygen Species-Thymic Stromal Lymphopoietin Inflammation and Epithelial Tight Junction Degradation

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.

Expression of protease-activated receptor 2 in uveal melanoma and its effect on cell proliferation and invasion / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the expression of protease-activated receptor 2(PAR2)in uveal melanoma(UM), and the effects of silencing the expression of PAR2 gene on proliferation and invasion of human UM cell line M23. <p>METHODS: A total of 45 patients(45 eyes)with UM who underwent surgical treatment with complete information in our hospital were selected from February 2012 to December 2017. In the same period, 30 patients(30 eyes)who underwent eyeball removal due to ocular trauma and most of the uvea were normal were selected. Real-time quantitative PCR was used to detect the expressions of PAR2 gene in UM and normal choroidal tissues. M23 cells were cultured and divided into PAR2 interference group, negative control sequence group and blank group. Real-time quantitative PCR was used to detect the expression of PAR2 gene in cells. MTT assay was used to detect cell proliferation, and transwell assay was used to detect cell migration and invasion. <p>RESULTS: The relative expression level of PAR2 mRNA was 1.73±0.13 in UM tissues, and 1.06±0.10 in normal choroid tissues(<i>t</i>=23.732, <i>P</i><0.001). The relative expression level of PAR2 mRNA in UM tissues was associated with pathological type, scleral invasion, optic disc involvement and extraocular growth(<i>P</i><0.05). The relative expression level of PAR2 mRNA in PAR2 interference group was lower than that in negative control sequence group and blank group(<i>P</i><0.05). The absorbance <i>A</i> values at 24h, 48h, 72h and 96h in the PAR2 interference group cells were lower than those in negative control sequence group and blank group(<i>P</i><0.05). The number of migrated cells and the number of invasive cells in PAR2 interference group were lower than those in negative control sequence group and blank group(<i>P</i><0.05). <p>CONCLUSION: PAR2 was highly expressed in UM tissues and was associated with high risk of tumor metastasis. Specific silencing of PAR2 gene expression in M23 cells could effectively inhibit cell proliferation, migration and invasion.

The role of protease activated receptor 2 in visceral sensitivity of irritable bowel syndrome patients / 西安交通大学学报(医学版)

ABSTRACT:Objective To investigate the role of PAR2 in the visceral sensitivity of IBS patients by observing the expression of rectal PAR2 in patients with irritable bowel syndrome and the effect of exogenous PAR2 on visceral sensitivity.Methods Based on Rome III criteria,16 patients with constipation predominant IBS (IBS-C),18 patients with diarrhea predominant IBS (IBS-D ),and 1 8 controls were selected from our hospital inpatient and outpatient departments. All the patients received colonoscopic examination and rectal mucosa biopsies. The expression of rectal mucosa PAR2 was observed by immunohistochemistry and Real-time fluorescence quantitative PCR.We studied the abdominal reactions by administering the PAR2 agonist in the rectal mucosa of rats to explore whether PAR2 is involved in visceral sensitivity.Results The results of PAR2 immunohistochemistry showed that PAR2 was mainly expressed in intestinal epithelial cells,especially in the villi;in addition,endothelial cells were also found positive.While the integral optical density (IA)of PAR2 expression did not significantly differ between IBS-D or IBS-C patients and controls according to the IPP image analysis.The PAR2 mRNA level in IBS-D or IBS-C patients was not significantly different from that of the control group by Real-time PCR analysis.There was no significant difference between the IBS-D and IBS-C groups.The EMG activity significantly increased in a volume-dependent manner during the rectal balloon expansion in the PAR2 agonist group.However,there was little EMG activity when the balloon was not dilated.The area under the curve in the PAR2 agonist group with 0 mL,0.4 mL and 0.6 mL of distension volume did not differ compared with that of the vehicle group.When the balloon volume increased to 0.8 mL,1.0 mL and 1.2 mL,the EMG activity was statistically significant (P<0.01)in the PAR2 agonist group compared with the control group.Conclusion PAR2 is highly expressed in the rectal mucosa of IBS patients.Administration of exogenous PAR2 agonist increases visceral sensitivity,suggesting that PAR2 is involved in visceral sensitivity.

Research progress in medicines on protease-activated receptor 2 / 药学学报

Protease-activated receptor 2 (PAR2) is a member of protease-activated receptors (PARs). PAR2 distributed in tissues and cells (such as skin, airway epithelial cell, pancreas, etc.) has a broad biological effects, and is involved in pathogenesis of many diseases, such as mechanical pain, asthma, pain of pancreatic cancer, inflammation, pruritus, etc. Intervention of PAR2 will help us to identify the role of PAR2 in the mechanisms of diseases and in the development of new drugs. This article concentrates on the research progress of agonist, antagonist, and pepducin on PAR2.

Role of PAR-2 in tryptase mediated IEC-6 cell injury / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the role of protease activated receptor-2 ( PAR-2 ) in the process of tryptase mediated IEC-6 cell injury.METHODS:The rat intestinal epithelial cell line IEC-6 was treated with tryptase at different concentrations (1 μg/L, 10 μg/L, 100μg/L and 1 000μg/L) in the presence or absence of PAR-2 antagonist FSLLRY-NH2 for 12 h respectively.The cell survival rate was detected by MTT assay.The protein levels of PAR-2 and cleaved-caspase 3 were determined by Western blotting.The LDH activity was also measured.RESULTS:Compared with control group, the cell survival rates were significantly decreased in 100 μg/L and 1 000 μg/L tryptase treated groups, the LDH activities were significantly increased in 10 μg/L to 1 000 μg/L tryptase treated groups, and the protein levels of PAR-2 and cleaved caspase 3 were significantly increased in 100μg/L and 1 000μg/L tryptase treated groups (P<0.05).Com-pared with 1 000 μg/L tryptase treated group, the LDH activity and cleaved caspase 3 protein level were dramatically de-creased while the survival rate was significantly increased in the presence of PAR-2 antagonist FSLLRY-NH2 (P<0.05). CONCLUSION:Tryptase induces IEC-6 cell injury in a dose-dependent manner by activating PAR-2.

Suppression of Peripheral Sympathetic Activity Underlies Protease-Activated Receptor 2-Mediated Hypotension

Protease-activated receptor (PAR)-2 is expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although some reports have suggested involvement of a neurogenic mechanism in PAR-2-induced hypotension, the accurate mechanism remains to be elucidated. To examine this possibility, we investigated the effect of PAR-2 activation on smooth muscle contraction evoked by electrical field stimulation (EFS) in the superior mesenteric artery. In the present study, PAR-2 agonists suppressed neurogenic contractions evoked by EFS in endothelium-denuded superior mesenteric arterial strips but did not affect contraction elicited by the external application of noradrenaline (NA). However, thrombin, a potent PAR-1 agonist, had no effect on EFS-evoked contraction. Additionally, omega-conotoxin GVIA (CgTx), a selective N-type Ca2+ channel (I(Ca-N)) blocker, significantly inhibited EFS-evoked contraction, and this blockade almost completely occluded the suppression of EFS-evoked contraction by PAR-2 agonists. Finally, PAR-2 agonists suppressed the EFS-evoked overflow of NA in endothelium-denuded rat superior mesenteric arterial strips and this suppression was nearly completely occluded by omega-CgTx. These results suggest that activation of PAR-2 may suppress peripheral sympathetic outflow by modulating activity of I(Ca-N) which are located in peripheral sympathetic nerve terminals, which results in PAR-2-induced hypotension.

The Cockroach and Allergic Diseases

The cockroach represents one of the most common sources of indoor allergens worldwide, and 40%-60% of patients with asthma in urban and inner-city areas possess IgE antibodies to cockroach allergens. In Korean homes, four cockroach species have been found, of which the most commonly encountered is the German cockroach. The pathogenic mechanism underlying the association between cockroach allergens and allergic diseases has not been fully elucidated. Allergenicity is associated with the cockroach allergens themselves, enzymatic protease activity, and ligands for pattern recognition receptors. Although allergen-specific adaptive immune responses orchestrate the cockroach allergic response, recent data suggest that the innate immune system is also a critical contributor to pathogenesis. We review the current evidence for the demographics of cockroach exposure and sensitization, characteristics of cockroach allergens, and inflammatory responses to cockroach allergens initiated through protease-dependent pathways.

Protease-Activated Receptor 2 Is Involved in Th2 Responses against Trichinella spiralis Infection

In order to get a better understanding of the role of protease-activated receptor 2 (PAR2) in type 2 helper T (Th2) cell responses against Trichinella spiralis infection, we analyzed Th2 responses in T. spiralis-infected PAR2 knockout (KO) mice. The levels of the Th2 cell-secreted cytokines, IL-4, IL-5, and IL-13 were markedly reduced in the PAR2 KO mice as compared to the wild type mice following infection with T. spiralis. The serum levels of parasite-specific IgE increased significantly in the wild type mice as the result of T. spiralis infection, but this level was not significantly increased in PAR2 KO mice. The expression level of thymic stromal lymphopoietin, IL-25, and eotaxin gene (the genes were recently known as Th2 response initiators) of mouse intestinal epithelial cells were increased as the result of treatment with T. spiralis excretory-secretory proteins. However, the expression of these chemokine genes was inhibited by protease inhibitor treatments. In conclusion, PAR2 might involve in Th2 responses against T. spiralis infection.

Effects of PR3 and protease-activated receptor-2-activators on the maturation and functions of dendritic cell-like monocytes / 中华风湿病学杂志

Objective To assess the effects of protease 3(PR3)and protease-activated receptor (PAR)-2-activator on the maturation and functions of peripheral blood dendritic cell(DC)-like monocytes.Methods Density gradient centrifugation was used to isolate peripheral blood mononuclear cells(PBMC)from Wegener's granulomatosis(WG)patients and healthy controls(HC).PBMC were stimulated by LPS,human PR3,trypsin,PAR-2-agonist peptide (PAR-2-AP),LPS+PR3 or LPS+trypsin for 24 h.Flow cytometry was used to analyze the expression of PAR-2,CD80,CD83,HLA-DR on stimulated DC-like monocytes-CD14+CD16high monocytes.ELISA kit was used to test the concentration of IL-6 in the culture supernants.Mann-Whitney non-parameteric test was used fur statistical analysis.Resuits No effect of PR3,trypsin and PAR-2-AP on the expression of PAR-2,CD80,CD83,HLA-DR of DC-like monoeytes was found.LPS could significantly induce PAR-2 expression in HC[from(5.8±1.5)%to(24.5±4.5)%,P=0.002]and the expression of CD80,CD83,HLA-DR in HC and WG;PR3,trypsin,PAR-2-AP and LPS could all stimulate the secretion of IL-6.Conclusion PR3 and PAR-2 pathway-activators can not promote PAR-2expression and maturation of DC-tike monocytes,but they can induce the secretion of IL-6.

Effects of Aspergillus fumigatus extract on expression of GM-CSF in human bronchial epithelial cells / 第二军医大学学报

Objective: To investigate the effects of Aspergillus fumigatus extract (AFE) on the expression of GM-CSF in human bronchial epithelial cells and its possible mechanism. Methods: Human bronchial epithelial cells (16HBE-14o) were cultured in vitro and were exposed to different concentrations of AFE (0, 8, 16 and 20 mg/L) for different peroids (12, 24, 48, 72 h). Moreover, heat-treated AFE, serine protease inhibitors (aprotinin), protease-activated receptor-2 (PAR 2) agonist (SLIGLV-NH2) and PAR-2 antagonist (FSLLRY-NH2) were also used to treat 16HBE-14o cells. The production and release of GM-CSF in different supernatants was determined by ELISA. The expression of GM-CSF mRNA was measured by RT-PCR. Results: 16HBE-14o cells in the normal control group only had slight expression of GM CSF; the expression was significantly increased after AFE treatment(P<0.01); and the effect of AFE was in a time- and dose-dependent manner. PAR 2 agonist also promoted release of GM-CSF. Aprotinin and PAR-2 antagonist (FSLLRY-NH2) almost totally inhibited the effect of AFE on GM-CSF production by 16HBE-14o cells. Heat-treated AFE, which lost protease activities, exerted no effect on GM-CSF production. Conclusion: AFE, with its protease activity, can activate PAR 2, and subsequently causes GM-CSF synthesis and release by airway epithelial cells, which may contribute to the development and deterioration of asthma.

Role of protease activated receptor-2 in rheumatoid arthritis: Recent progress / 第二军医大学学报

Protease activated receptor-2 (PAR-2) is a G-protein-coupled receptor. Recent studies indicate that PAR-2 is mainly expressed in leukocytes and activated by pancreatin and (or) tryptase, which subsequently induces inflammation through degranulation of leukocytes. Activation of PAR-2 in leukocytes is possibly involved in the pathogenesis of rheumatoid arthritis.

Protease and Protease-Activated Receptor-2 Signaling in the Pathogenesis of Atopic Dermatitis

Proteases in the skin are essential to epidermal permeability barrier homeostasis. In addition to their direct proteolytic effects, certain proteases signal to cells by activating protease-activated receptors (PARs), the G-protein-coupled receptors. The expression of functional PAR-2 on human skin and its role in inflammation, pruritus, and skin barrier homeostasis have been demonstrated. Atopic dermatitis (AD) is a multifactorial inflammatory skin disease characterized by genetic barrier defects and allergic inflammation, which is sustained by gene-environmental interactions. Recent studies have revealed aberrant expression and activation of serine proteases and PAR-2 in the lesional skin of AD patients. The imbalance between proteases and protease inhibitors associated with genetic defects in the protease/protease inhibitor encoding genes, increase in skin surface pH, and exposure to proteolytically active allergens contribute to this aberrant protease/PAR-2 signaling in AD. The increased protease activity in AD leads to abnormal desquamation, degradation of lipid-processing enzymes and antimicrobial peptides, and activation of primary cytokines, thereby leading to permeability barrier dysfunction, inflammation, and defects in the antimicrobial barrier. Moreover, up-regulated proteases stimulate PAR-2 in lesional skin of AD and lead to the production of cytokines and chemokines involved in inflammation and immune responses, itching sensation, and sustained epidermal barrier perturbation with easier allergen penetration. In addition, PAR-2 is an important sensor for exogenous danger molecules, such as exogenous proteases from various allergens, and plays an important role in AD pathogenesis. Together, these findings suggest that protease activity or PAR-2 may be a future target for therapeutic intervention for the treatment of AD.

Effects of PAR-2 agonist peptide on proliferation and cytosolic calcium level in hepatoma cells / 中国病理生理杂志

AIM: To investigate the effects of PAR-2 agonist peptide on the proliferation and cytosolic calcium concentration ([Ca~(2+)]_c) in human hepatoma cells HepG2. METHODS: Human hepatoma cell line HepG2 was cultured. The cells were treated with PAR-2 agonist peptide SLIGKV-NH_2 and the reverse PAR-2 agonist peptide VKGILS-NH_2, respectively. The [Ca~(2+)]_c of hepatoma cells were measured by microfluorimetric techniques based on calcium indicator fura-2/AM. The influences on proliferation of hepatoma cells were determined by MTT method. The changes of cell cycle were evaluated by flow cytometry, and the changes of cyclin D1 mRNA expression were detected by RT-PCR. RESULTS: After treated with 50 μmol/L SLIGKV-NH_2, a rapid rise of [Ca~(2+)]_c in HepG2 cells was induced (P<0.01), percent S phase, G_2/M phase and proliferation index (PI) of HepG2 cells were elevated (P<0.01), and cyclin D1 mRNA expression was significantly upregulated (P<0.01). The proliferation rates of HepG2 cells treated with 1-50 μmol/L SLIGKV-NH_2 were significantly increased, and the effect was in a dose-dependent manner (P<0.01 or P<0.05). No statistical significance of the difference between VKGILS-NH_2 and control group was observed (P>0.05). CONCLUSION: PAR-2 agonist peptide induces the rise of [Ca~(2+)]_c in HepG2 cells, upregulates the expression of cyclin D1 mRNA, accelerates the progress of cell cycle, promotes the synthesis of DNA and the proliferation of hepatoma cells via activating PAR-2 in vitro.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

An Update of the Defensive Barrier Function of Skin

Skin, as the outermost organ in the human body, continuously confronts the external environment and serves as a primary defense system. The protective functions of skin include UV-protection, anti-oxidant and antimicrobial functions. In addition to these protections, skin also acts as a sensory organ and the primary regulator of body temperature. Within these important functions, the epidermal permeability barrier, which controls the transcutaneous movement of water and other electrolytes, is probably the most important. This permeability barrier resides in the stratum corneum, a resilient layer composed of corneocytes and stratum corneum intercellular lipids. Since the first realization of the structural and biochemical diversities involved in the stratum corneum, a tremendous amount of work has been performed to elucidate its roles and functions in the skin, and in humans in general. The perturbation of the epidermal permeability barrier, previously speculated to be just a symptom involved in skin diseases, is currently considered to be a primary pathophysiologic factor for many skin diseases. In addition, much of the evidence provides support for the idea that various protective functions in the skin are closely related or even co-regulated. In this review, the recent achievements of skin researchers focusing on the functions of the epidermal permeability barrier and their importance in skin disease, such as atopic dermatitis and psoriasis, are introduced.

Role of Protease Activated Receptor-2 Expression in Renal Interstitial Fibrosis Model in Mice / 华中科技大学学报（医学）（英德文版）

The role of protease activated receptor-2 (PAR-2) in the renal tubulointerstitial lesion induced by unilateral ureteral obstruction (UUO) was explored. Mice were sacrificed on the day 1,3, 5, 7, 10, 14 and 21 after UUO. The expression of PAR-2 mRNA and protein and α-smooth muscle actin (α-SMA) protein in tubulointerstitium was detected by RT-PCR and immunohistochemistry at each time point, respectively. The results showed that the PAR-2 expression in renal tubulointerstitium was increased progressively starting from 24 h to the day 14 post-ligation, and it was significantly associated with the relative volume of interstitium and the positive area of α-SMA.PAR-2 was mainly expressed in renal tubule epithelial cells, especially in proximal tubular cells. It also located in renal capillary ansa, interstitial infiltrate cells and fibroblasts. It was concluded that PAR-2 was active in interstitial and tubular cells in the early phase of fibrotic process and played an important role in mediating the tubulointerstitial lesion after UUO.

Protease-activated Receptor 2 is Associated with Activation of Human Macrophage Cell Line THP-1

BACKGROUND: Protease-activated receptor 2 (PAR2) belongs to a family of G protein- coupled receptors activated by proteolytic cleavage. Trypsin-like serine proteases interact with PAR2 expressed by a variety of tissues and immune cells. The aim of our study was to investigate whether PAR2 stimulation can lead to the activation of human macrophages. METHODS: PAR2-mediated proliferation of human macrophage cell line THP-1 was measured with MTT assay. We also examined the extracellular regulated kinase (ERK) phosphorylation and cytokine production induced by trypsin and PAR2-agonist using western blot and enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: Treatment of trypsin or PAR2-activating peptide increased cell proliferation in a dose-dependent manner, and induced the activation of ERK1/2 in THP-1 cells. In addition, trypsin-induced cell proliferation was inhibited by pretreatment of an ERK inhibitor (PD98059) or trypsin inhibitor (SBTI). Moreover, PAR2 activation by trypsin increased the secretion of TNF-alpha in THP-1 cells. CONCLUSION: There results suggest that PAR2 activation by trypsin-like serine proteases can induce cell proliferation through the activation of ERK in human macrophage and that PAR2 may play a crucial role in the cell proliferation and cytokine secretion induced by trypsin-like serine proteases.