Plasminogen Activator Inhibitor-1 mRNA Research Articles

Expression of PAI-2 mRNA in peripheral blood leucocytes and regulation by sGC activator in pulmonary hypertension

To investigate the mRNA expression level of plasminogen activator inhibitor-2 (PAI-2) in peripheral blood leucocytes and regulation by soluble guanylate cyclase (sGC) activator in pulmonary hypertension. The human pulmonary arterial smooth muscle cells were treated with sGC activator Cinaciguat. The mRNA and protein expression levels of PAI-2 were detected with Real-time PCR and Western blot. The fresh blood samples of 8 patients with pulmonary arterial hypertension (PAH) (collected at the China-Japan Friendship Hospital from November 2014 to March 2015), 16 patients with chronic thromboembolic pulmonary hypertension (CTEPH) (collected at the China-Japan Friendship Hospital from November 2014 to March 2015), 24 age- and gender- matched healthy controls (collected at Beijing Hospital in March 2015) were treated with Cinaciguat for 8 hours. Then RNA of peripheral leukocytes was extracted and performed with reverse transcription and Real-time PCR to detect the mRNA level of PAI-2, which was compared between healthy controls and patients with pulmonary hypertension, before and after the treatment of Cinaciguat. At last, the correlation of PAI-2 mRNA level and the clinic severity of pulmonary hypertension were identified. The mRNA and protein expression levels of PAI-2 were promoted by Cinaciguat in human pulmonary arterial smooth muscle cells. The baseline mRNA level of PAI-2 in peripheral leukocytes was significantly lower in PAH patients compared to the healthy controls (0.201±0.152, 0.660±0.440, P=0.021). There was no significant difference in the mRNA expression level of PAI-2 between the CTEPH patients and controls (0.428±0.364, 0.769±0.682, P=0.152). After Cinaciguat treatment, the mRNA expression levels of PAI-2 were up-regulated in PAH patients and CTEPH patients (1.352±1.127, 1.203±1.008), there was no significant difference in the mRNA expression level of PAI-2 among the PAH patients, CTEPH patients and controls (P=0.130, P=0.534). The baseline mRNA level of PAI-2 was negative correlated with echocardiography-estimated systolic pulmonary arterial pressure (sPAP) (r=-0.744, P=0.034). The mRNA expression level of PAI-2 is significantly down-regulated in peripheral blood leucocytes and up-regulated by sGC activator in pulmonary hypertension. PAI-2 could be used as potential biomarker of pulmonary vascular remodeling in PAH.

Periodontal dysbiosis linked to periodontitis is associated with cardiometabolic adaptation to high-fat diet in mice.

Periodontitis and type 2 diabetes are connected pandemic diseases, and both are risk factors for cardiovascular complications. Nevertheless, the molecular factors relating these two chronic pathologies are poorly understood. We have shown that, in response to a long-term fat-enriched diet, mice present particular gut microbiota profiles related to three metabolic phenotypes: diabetic-resistant (DR), intermediate (Inter), and diabetic-sensitive (DS). Moreover, many studies suggest that a dysbiosis of periodontal microbiota could be associated with the incidence of metabolic and cardiac diseases. We investigated whether periodontitis together with the periodontal microbiota may also be associated with these different cardiometabolic phenotypes. We report that the severity of glucose intolerance is related to the severity of periodontitis and cardiac disorders. In detail, alveolar bone loss was more accentuated in DS than Inter, DR, and normal chow-fed mice. Molecular markers of periodontal inflammation, such as TNF-α and plasminogen activator inhibitor-1 mRNA levels, correlated positively with both alveolar bone loss and glycemic index. Furthermore, the periodontal microbiota of DR mice was dominated by the Streptococcaceae family of the phylum Firmicutes, whereas the periodontal microbiota of DS mice was characterized by increased Porphyromonadaceae and Prevotellaceae families. Moreover, in DS mice the periodontal microbiota was indicated by an abundance of the genera Prevotella and Tannerella, which are major periodontal pathogens. PICRUSt analysis of the periodontal microbiome highlighted that prenyltransferase pathways follow the cardiometabolic adaptation to a high-fat diet. Finally, DS mice displayed a worse cardiac phenotype, percentage of fractional shortening, heart rhythm, and left ventricle weight-to-tibia length ratio than Inter and DR mice. Together, our data show that periodontitis combined with particular periodontal microbiota and microbiome is associated with metabolic adaptation to a high-fat diet related to the severity of cardiometabolic alteration.

P53- and PAI-1-mediated induction of C-X-C chemokines and CXCR2: importance in pulmonary inflammation due to cigarette smoke exposure.

We previously demonstrated that tumor suppressor protein p53 augments plasminogen activator inhibitor-1 (PAI-1) expression in alveolar epithelial cells (AECs) during chronic cigarette smoke (CS) exposure-induced lung injury. Chronic lung inflammation with elevated p53 and PAI-1 expression in AECs and increased susceptibility to and exacerbation of respiratory infections are all associated with chronic obstructive pulmonary disease (COPD). We recently demonstrated that preventing p53 from binding to the endogenous PAI-1 mRNA in AECs by either suppressing p53 expression or blockading p53 interactions with the PAI-1 mRNA mitigates apoptosis and lung injury. Within this context, we now show increased expression of the C-X-C chemokines (CXCL1 and CXCL2) and their receptor CXCR2, and the intercellular cellular adhesion molecule-1 (ICAM-1), in the lung tissues of patients with COPD. We also found a similar increase in lung tissues and AECs from wild-type (WT) mice exposed to passive CS for 20 wk and in primary AECs treated with CS extract in vitro. Interestingly, passive CS exposure of mice lacking either p53 or PAI-1 expression resisted an increase in CXCL1, CXCL2, CXCR2, and ICAM-1. Furthermore, inhibition of p53-mediated induction of PAI-1 expression by treatment of WT mice exposed to passive CS with caveolin-1 scaffolding domain peptide reduced CXCL1, CXCL2, and CXCR2 levels and lung inflammation. Our study reveals that p53-mediated induction of PAI-1 expression due to chronic CS exposure exacerbates lung inflammation through elaboration of CXCL1, CXCL2, and CXCR2. We further provide evidence that targeting this pathway mitigates lung injury associated with chronic CS exposure.

Peroxisome proliferator-activated receptor-α-mediated transcription of miR-301a and miR-454 and their host gene SKA2 regulates endothelin-1 and PAI-1 expression in sickle cell disease.

Endothelin-1 (ET-1) and plasminogen activator inhibitor-1 (PAI-1) play important roles in pulmonary hypertension (PH) in sickle cell disease (SCD). Our previous studies show higher levels of placenta growth factor (PlGF) in SCD correlate with increased plasma levels of ET-1, PAI-1, and other physiological markers of PH. PlGF-mediated ET-1 and PAI-1 expression occurs via activation of hypoxia-inducible factor-1α (HIF-1α). However, relatively little is understood regarding post-transcriptional regulation of PlGF-mediated expression of ET-1 and PAI-1. Herein, we show PlGF treatment of endothelial cells reduced levels of miR-301a and miR-454 from basal levels. In addition, both miRNAs targeted the 3'-UTRs of ET-1 and PAI-1 mRNAs. These results were corroborated in the mouse model of SCD [Berkeley sickle mice (BK-SS)] and in SCD subjects. Plasma levels of miR-454 in SCD subjects were significantly lower compared with unaffected controls, which correlated with higher plasma levels of both ET-1 and PAI-1. Moreover, lung tissues from BK-SS mice showed significantly reduced levels of pre-miR-301a and concomitantly higher levels of ET-1 and PAI-1. Furthermore, we show that miR-301a/miR-454 located in the spindle and kinetochore-associated protein-2 (SKA2) transcription unit was co-transcriptionally regulated by both HIF-1α and peroxisome proliferator-activated receptor-α (PPAR-α) as demonstrated by SKA2 promoter mutational analysis and ChIP. Finally we show that fenofibrate, a PPAR-α agonist, increased the expression of miR-301a/miR-454 and SKA2in human microvascular endothelial cell line (HMEC) cells; the former were responsible for reduced expression of ET-1 and PAI-1. Our studies provide a potential therapeutic approach whereby fenofibrate-induced miR-301a/miR-454 expression can ameliorate PH and lung fibrosis by reduction in ET-1 and PAI-1 levels in SCD.

Decidualisation of human endometrial stromal cells is associated with increased expression and secretion of prorenin.

BackgroundIn pregnancy, the decidualised endometrium expresses high levels of prorenin and other genes of the renin-angiotensin system (RAS) pathway. In this study we aimed to determined if the RAS was present in endometrial stromal cells and if decidualisation upregulated the expression of prorenin, the prorenin receptor ((P)RR) and associated RAS pathways. Immortalised human endometrial stromal cells (HESCs) can be stimulated to decidualise by combined treatment with medroxyprogesterone acetate (MPA), 17β-estradiol (E2) and cAMP (MPA-mix) or with 5-aza-2’-deoxycytidine (AZA), a global demethylating agent.MethodsHESCs were incubated for 10 days with one of the following treatments: vehicle, MPA-mix, a combination of medroxyprogesterone acetate (MPA) and estradiol-17β alone, or AZA. Messenger RNA abundance and protein levels of prorenin (REN), the (P)RR (ATP6AP2), angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AGTR1), vascular endothelial growth factor (VEGF), and plasminogen activator inhibitor-1 (PAI-1) were measured by real-time PCR and ELISA’s, respectively. Promyelocytic zinc finger (PLZF) and phospho-inositol-3 kinase (PIK3R1) mRNA abundances were also measured.ResultsHESCs expressed the prorenin receptor (ATP6AP2), REN, AGT, ACE and low levels of AGTR1. MPA-mix and AZA stimulated expression of REN. Prorenin protein secretion was increased in MPA-mix treated HESCs. E2 + MPA had no effect on any RAS genes. MPA-mix treatment was associated with increased VEGF (VEGFA) and PAI-1 (SERPINE1) mRNA and VEGF protein.ConclusionsAn endometrial prorenin receptor/renin angiotensin system is activated by decidualisation. Since (P)RR is abundant, the increase in prorenin secretion could have stimulated VEGF A and SERPINE1 expression via Ang II, as both ACE and AGTR1 are present, or by Ang II independent pathways. Activation of the RAS in human endometrium with decidualisation, through stimulation of VEGF expression and secretion, could be critical in establishing an adequate blood supply to the developing maternal placental vascular bed.

Abstract 19834: MicroRNA-148a Inhibits Expression of Plasminogen Activator Inhibitor-1: Mechanistic Implications for Obesity-associated Thrombosis

Obesity is an epidemic in developed countries and is associated with an increased incidence of arterial and venous thrombosis. The mechanisms of obesity-induced thrombosis, however, are not well defined. In the current study, we tested the hypothesis that diet-induced obesity causes alterations in microRNA expression that may predispose to thrombosis. To induce obesity, C57Bl/6J mice were fed a 60% high fat diet. Compared with lean mice, obese mice had elevated fasting levels of glucose and insulin resistance, and exhibited acceleration of carotid artery thrombosis after photochemical injury (P<0.01) and increased susceptibility to venous thrombosis induced by inferior vena cava ligation (P<0.05). Plasma levels of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of fibrinolysis secreted by adipocytes and endothelial cells, were elevated 3-fold in obese mice, suggesting a potential mechanism of thrombosis in diet-induced obesity. TaqMan low-density microRNA arrays detected downregulation of 41 microRNAs in plasma exosomes from obese mice (P<0.05). Bioinformatic analysis of the downregulated microRNAs in relation to the PAI-1 3’-UTR identified microRNA-148a as a potential inhibitor of PAI-1 expression in obesity. We found that levels of PAI-1 mRNA were increased 4.5-fold (P<0.05) and levels of microRNA-148a decreased 4-fold (P<0.05) in white adipose tissue from obese mice compared with lean mice. Transfection of primary adipocytes or a murine endothelial cell line (MS-1) with a microRNA-148a mimetic resulted in 50-70% downregulation of PAI-1 expression (P<0.05), demonstrating a causal inverse relationship between microRNA-148a and PAI-1 mRNA. Our findings suggest that downregulation of microRNA-148a in diet-induced obesity may promote thrombosis through loss of repression of PAI-1 expression at the mRNA level.

Gene expression of different adipose tissues of severely obese women with or without a dysmetabolic profile

Despite well-established variations in the health risks posed by visceral vs. subcutaneous abdominal (SCABD) fat depots, surprisingly little is known on the differences within a given adipose tissue (AT) among severely obese patients displaying varying metabolic dysfunction. We thus compared, by quantitative PCR, the expression profile of a number of genes in the SCABD, omental (OME), and mesenteric (MES) depots of severely obese women with (DYS; n = 25) or without (NDYS; n = 23) a dysmetabolic profile. Fasting insulinemia and HOmeostasis Model Assessment-insulin resistance (HOMA-IR) were higher and plasma adiponectin level lower in DYS women (p < 0.05). Among enzymes involved in fatty acid metabolism and local cortisol production, phosphodiesterase-3B expression was lower in SCABD and MES fat, while 11β-hydroxysteroid dehydrogenase type 1 mRNA levels were higher in visceral depots of DYS women (p < 0.05). Regarding vascular homeostasis and inflammation, plasminogen activator inhibitor-1 and interleukin-6 mRNA levels were higher in OME fat, while adiponectin expression was lower in SCABD and OME ATs of DYS women (p < 0.05). Finally, HOMA-IR was positively associated with SCABD AT IL6 mRNA, only in DYS women (r = 0.47; p < 0.05). In conclusion, although metabolic and secretory characteristics of all depots vary with subjects' metabolic profile, we find little evidence for a protective role of SCABD AT and no evidence for a further deleterious role of MES fat in DYS vs. NDYS severely obese women. Regional variation in the overall gene expression revealed that OME and MES fat were more closely related to each other in DYS women, while SCABD and MES depots showed greater resemblance in NDYS women.

Effects of urokinase type plasminogen activator and plasminogen activator inhibitor-1 expressions on the formation of aneurysm of perimembranous ventricular septal defect

The exact mechanisms of defect closure in patients with perimembranous ventricular septal defect (PMVSD) remain unknown. We hypothesized that the expression of urokinase type plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) may mediate extracellular matrix (ECM) remodeling in aneurysms. Seven normal heart tricuspid septal leaflet and 33 aneurysms were collected in Shanghai Renji Hospital and Shanghai Children's Medical Center from January 2008 to June 2010. Immunohistochemical expression of uPA and PAI-1 in 4 normal heart valvular tissues and 15 aneurysms was detected with immunohistochemical methods. The expression of uPA and PAI-1 mRNA in 3 normal heart valvular tissues and 7 aneurysms was studied by real time fluorescent PCR; the protein expression of uPA and PAI-1 in 4 normal heart valvular tissues and 11 aneurysms was tested with Western blotting. The surface of the aneurysms were completely covered by endothelial cells. Two types of granulation tissue, myxoid and fibrous, were associated with the aneurismal formation. uPA were recognized predominantly in valvar interstitial cells (VICs) which located mainly in regions adjacent to the endothelium and smooth muscle cells of blood vessels. PAI-1 was found in both VICs which located mainly in granulation tissue and endothelial cells. Nine aneurysms expressed a higher uPA activity than 4 normal valvular tissues ((74.6±11.8)% vs. (49.5±7.4)%; t = 3.87, P = 0.003) and six aneurysms expressed a low uPA activity ((10.3±3.1)% vs. (49.5±7.4)%; t=11.78, P=0.000) and a high PAI-1 activity ((55.2±1.7)% vs. (50.8±3.8)%; t=2.55, P=0.034) using immunohistochemical methods. uPA / PAI-1 ratio of protein expression tested by Western blot was 0.88±0.22 in four normal heart vavular tissues; five aneurysms expressed high uPA activity and low PAI-1 activity and uPA/PAI-1 ratio was 4.26±2.04; while the other 6 cases expressed low uPA activity and high PAI-1 activity and uPA/PAI-1 ratio was 0.30±0.07; the difference among the three groups was statistically significant (P<0.05). The rate of uPA/PAI-1 in relative copy of mRNA expression among normal heart valvular tissue, high uPA expressed aneurysms and low uPA expressed aneurysms are also significantly different (2.14±0.17 vs. 0.45±0.04; 2.14±0.17 vs. 4.38±1.41, P<0.05) respectively. The expression of uPA and PAI-1 in VICs suggests that interactions among these molecules contribute to the aneurysm formation and development. This provides a potential mechanism for defect closure in patients with PMVSD.

Efficacy and mechanism of tanshinone IIA liquid nanoparticles in preventing experimental postoperative peritoneal adhesions in vivo and in vitro.

Up to 90% of patients develop adhesion following laparotomy. Upregulating fibrinolysis within the peritoneum reduces adhesions. Tanshinone IIA (Tan IIA) promotes fibrinolysis in hepatic fibrosis and the cardiovascular system and may play a role in preventing adhesions. We report preparation and characterization of liquid nanoparticles of Tan IIA for intravenous administration and investigate its feasibility in clinical practice. Tan IIA liquid nanoparticles (Tan IIA-NPs) were prepared using the emulsion/solvent evaporation method. Adhesions were induced in Sprague–Dawley rats by injuring the parietal peritoneum and cecum, followed by intravenous administration of various Tan IIA-NP dosages. The adhesion scores for each group were collected 7 days after the initial laparotomy. The activity of tissue-type plasminogen activator (tPA) was measured from the peritoneal lavage fluid. The messenger RNA and protein expression levels of plasminogen activator inhibitor-1 (PAI-1) were measured by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. TGF-β1 and collagen I expressions were measured immunohistochemically in the ischemic tissues. The effects of Tan IIA-NPs and free-Tan IIA on tPA and PAI-1 were measured in vitro in TGF-β1-induced HMrSV5 cells. Tan IIA-NPs exhibited small particle size, high encapsulation efficiency, good stability for storage, and safety for intravenous administration. Tan IIA-NPs were effective in preventing adhesion. Tan IIA-NPs increased tPA activity in peritoneal lavage fluid, and tPA mRNA and protein expression, and decreased PAI-1 mRNA and protein expression in the ischemic tissues. Moreover, Tan IIA-NPs decreased TGF-β1 and collagen I expressions in the ischemic tissues. Tan IIA-NPs administered via tail veins upregulated fibrinolysis in the peritoneum. In vitro studies showed that these effects may be mediated by the TGF-β signal pathway.

Suppression of plasminogen activator inhibitor-1 by inhaled nitric oxide attenuates the adverse effects of hyperoxia in a rat model of acute lung injury

IntroductionLocally increased expression of plasminogen activator inhibitor-1 (PAI-1) in acute lung injury (ALI) is largely responsible for fibrin deposition in the alveolae and lung microvasculature. In vitro, nitric oxide (NO) effectively suppresses the ischemic induction of PAI-1. We aimed to investigate the effects of inhaled NO on PAI-1 expression in ALI in a rat model with and without hyperoxia. Materials and MethodsHealthy adult rats were primed with lipopolysaccharide (LPS) via an intraperitoneal challenge followed by a second dose of LPS given intratracheally to induce ALI (LPS group), whereas the control groups were given sterile saline. All groups were allocated to subgroups according to gas exposure: NO (20 parts per million, NO), 95% oxygen (O), both (ONO), or room air (A). At 4h, 24h, 48h (after 4h or 24h exposure to the various gases, 24h gas intervention and then observation until 48h), the rat lungs were processed and PAI-1 protein and mRNA expression, histopathological lung injury scores and fibrin deposition were evaluated. ResultsAt 4 and 24h, inhaled NO caused the PAI-1 mRNA levels in the LPS-NO and LPS-ONO subgroups to decrease compared with the untreated LPS subgroups. At 48h, higher PAI-1 mRNA levels than those of the corresponding control subgroup were only observed in the LPS-O subgroup, and these values were lower in the LPS-ONO subgroup than in the LPS-O subgroup. The trends of the PAI-1 protein levels mirrored those of PAI-1 mRNA. At 48h, PAI-1 protein levels in the LPS-NO and LPS-ONO subgroups were decreased compared with those in the untreated LPS subgroups. The histopathological lung injury scores and fibrin deposition in LPS subgroups that inhaled NO showed a decreasing trend compared with the untreated LPS subgroups. ConclusionsInhaled NO can suppress elevated PAI-1 expression in rats with ALI induced by endotoxin. Although exposure to high-concentration oxygen prolongs the duration of PAI-1 mRNA overexpression in ALI, inhaled NO can reduce this effect and alleviate both fibrin deposition and lung injury.

Effect of ascorbate on plasminogen activator inhibitor-1 expression and release from platelets and endothelial cells in an in-vitro model of sepsis

The microcirculation during sepsis fails due to capillary plugging involving microthrombosis. We demonstrated that intravenous injection of ascorbate reduces this plugging, but the mechanism of this beneficial effect remains unclear. We hypothesize that ascorbate inhibits the release of the antifibrinolytic plasminogen activator inhibitor-1 (PAI-1) from endothelial cells and platelets during sepsis. Microvascular endothelial cells and platelets were isolated from mice. Cells were cultured and stimulated with lipopolysaccharide (LPS), tumor necrosis factor alpha (TNFα), or thrombin (agents of sepsis), with/without ascorbate for 1-24 h. PAI-1 mRNA was determined by quantitative PCR. PAI-1 protein release into the culture medium was measured by ELISA. In platelets, PAI-1 release was measured after LPS, TNFα, or thrombin stimulation, with/without ascorbate. In endothelial cells, LPS and TNFα increased PAI-1 mRNA after 6-24 h, but no increase in PAI-1 release was observed; ascorbate did not affect these responses. In platelets, thrombin, but not LPS or TNFα, increased PAI-1 release; ascorbate inhibited this increase at low extracellular pH. In unstimulated endothelial cells and platelets, PAI-1 is released into the extracellular space. Thrombin increases this release from platelets; ascorbate inhibits it pH-dependently. The data suggest that ascorbate promotes fibrinolysis in the microvasculature under acidotic conditions in sepsis.

A small molecule PAI-1 functional inhibitor attenuates neointimal hyperplasia and vascular smooth muscle cell survival by promoting PAI-1 cleavage

Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of urokinase-and tissue-type plasminogen activators (uPA and tPA), is an injury-response gene implicated in the development of tissue fibrosis and cardiovascular disease. PAI-1 mRNA and protein levels were elevated in the balloon catheter-injured carotid and in the vascular smooth muscle cell (VSMC)-enriched neointima of ligated arteries. PAI-1/uPA complex formation and PAI-1 antiproteolytic activity can be inhibited, via proteolytic cleavage, by the small molecule antagonist tiplaxtinin which effectively increased the VSMC apoptotic index in vitro and attenuated carotid artery neointimal formation in vivo. In contrast to the active full-length serine protease inhibitor (SERPIN), elastase-cleaved PAI-1 (similar to tiplaxtinin) also promoted VSMC apoptosis in vitro and similarly reduced neointimal formation in vivo. The mechanism through which cleaved PAI-1 (CL-PAI-1) stimulates apoptosis appears to involve the TNF-α family member TWEAK (TNF-α weak inducer of apoptosis) and it's cognate receptor, fibroblast growth factor (FGF)-inducible 14 (FN14). CL-PAI-1 sensitizes cells to TWEAK-stimulated apoptosis while full-length PAI-1 did not, presumably due to its ability to down-regulate FN14 in a low density lipoprotein receptor-related protein 1 (LRP1)-dependent mechanism. It appears that prolonged exposure of VSMCs to CL-PAI-1 induces apoptosis by augmenting TWEAK/FN14 pro-apoptotic signaling. This work identifies a critical, anti-stenotic, role for a functionally-inactive (at least with regard to its protease inhibitory function) cleaved SERPIN. Therapies that promote the conversion of full-length to cleaved PAI-1 may have translational implications.

Role of plasminogen activator inhibitor-1 in glucocorticoid-induced diabetes and osteopenia in mice.

Long-term use of glucocorticoids (GCs) causes numerous adverse effects, including glucose/lipid abnormalities, osteoporosis, and muscle wasting. The pathogenic mechanism, however, is not completely understood. In this study, we used plasminogen activator inhibitor-1 (PAI-1)-deficient mice to explore the role of PAI-1 in GC-induced glucose/lipid abnormalities, osteoporosis, and muscle wasting. Corticosterone markedly increased the levels of circulating PAI-1 and the PAI-1 mRNA level in the white adipose tissue of wild-type mice. PAI-1 deficiency significantly reduced insulin resistance and glucose intolerance but not hyperlipidemia induced by GC. An in vitro experiment revealed that active PAI-1 treatment inhibits insulin-induced phosphorylation of Akt and glucose uptake in HepG2 hepatocytes. However, this was not observed in 3T3-L1 adipocytes and C2C12 myotubes, indicating that PAI-1 suppressed insulin signaling in hepatocytes. PAI-1 deficiency attenuated the GC-induced bone loss presumably via inhibition of apoptosis of osteoblasts. Moreover, the PAI-1 deficiency also protected from GC-induced muscle loss. In conclusion, the current study indicated that PAI-1 is involved in GC-induced glucose metabolism abnormality, osteopenia, and muscle wasting in mice. PAI-1 may be a novel therapeutic target to mitigate the adverse effects of GC.

Role of urokinase plasminogen activator and plasminogen activator inhibitor mRNA expression as prognostic factors in molecular subtypes of breast cancer.

BackgroundProtein levels of urokinase plasminogen activator (uPA) and its inhibitor (PAI-1) determined by enzyme-linked immunosorbent assay from fresh-frozen tumor tissue have been evaluated as prognostic factors in prospectively randomized trials in breast cancer. However, the role of uPA and PAI-1 in the context of breast cancer subtypes and for mRNA expression of these factors is less clear.MethodsWe evaluated uPA and PAI-1 mRNA expression using the Affymetrix HG-U 133A array within molecular subgroups of breast cancer in cohorts of patients with systemic treatment (cohort A, n=362) and without systemic treatment (cohort B, n=200). We validated mRNA expression in a cohort of HER2-positive breast cancer patients (cohort C, n=290). Luminal, triple-negative, and HER2-positive subcohorts were defined by ESR1 and ERBB2 mRNA expression using predefined cutoffs.ResultsIn the entire cohort A, elevated PAI-1 but not uPA mRNA expression was associated with shorter disease-free survival (P=0.007 for PAI and 0.069 for uPA). Regarding different molecular subgroups, 67% (n=244) of tumors were luminal, 14% (n=49) were HER2-positive, and 19% (n=69) were triple-negative. Elevated PAI-1 mRNA expression was associated with shorter disease-free survival only in the HER2-positive subgroup (P=0.031). The same disease-free survival results were found for uPA in HER2-positive patients (P=0.011). In contrast, no association between either marker and survival was observed in the luminal or triple-negative subgroups. In the HER2-positive validation cohort C, elevated uPA and PAI-1 mRNA expression also showed strong associations with shorter disease-free survival (P=0.014 for PAI-1, P<0.001 for uPA).ConclusionIn this study, the prognostic impact of uPA and PAI-1 expression was mainly observed in patients with HER2-positive tumors.

Plasminogen activator inhibitor-1 regulates LPS-induced TLR4/MD-2 pathway activation and inflammation in alveolar macrophages.

Toll-like receptor 4 (TLR4) and myeloid differentiation protein 2 (MD-2) are the main lipopolysaccharide (LPS) binding receptors that respond to inflammatory stimuli and mediate NF-kappa B (NF-κB) signaling pathway in macrophages. We have previously shown that plasminogen activator inhibitor-1 (PAI-1) deletion increased lung injury induced by intratracheal instillation of LPS through downregulation of TLR4 negative regulators. However, the mechanisms by which PAI-1 regulates lung inflammation are largely unknown. The aim of this study is to assess the relationship between PAI-1 and TLR4 signaling pathways in LPS-induced NR8383 cells inflammatory reaction. The results showed that the levels of PAI-1, TNF-α, and IL-1β protein were increased remarkably in NR8383 cell supernatants after LPS stimulation. PAI-1 gene knockdown reduced TNF-α and IL-1β levels in cell supernatants and inhibited the NF-κB p65 protein expression in NR8383 cells. The upregulated mRNA and protein expressions of TLR4, MD-2, and myeloid differentiation protein (MyD88) induced by LPS were attenuated after PAI-1 gene knockdown. Conversely, overexpression of PAI-1 in NR8383 cells not only resulted in additional mRNA and protein production of PAI-1, TLR4, MD-2, and MyD88, it also aggravated the inflammatory response induced by LPS. In conclusion, PAI-1 contributes to the regulation of LPS-induced inflammatory response in NR8383 cells, likely by affecting the TLR4-MD-2/NF-κB signaling transduction pathway.

Effect of ascorbate on fibrinolytic factors in septic mouse skeletal muscle

Plugging of the capillary bed in tissues correlates with organ failure during sepsis. In septic mouse skeletal muscle, we showed that blood in capillaries becomes hypercoagulable and that ascorbate injection inhibits capillary plugging. In the present study, we hypothesized that ascorbate promotes fibrinolysis, reversing this plugging. Sepsis in mice was induced by fecal injection into peritoneum. Mice were injected intravenously with a bolus of streptokinase (fibrinolytic agent) or ascorbate at 5-6 h. Both agents reversed capillary plugging in muscle at 7 h. Sepsis increased mRNA expression of urokinase plasminogen activator (u-PA) (profibrinolytic) and plasminogen activator inhibitor 1 (PAI-1) (antifibrinolytic) in muscle and liver homogenates at 7 h. Ascorbate did not affect u-PA mRNA in either tissue, but it inhibited PAI-1 mRNA in muscle, suggesting enhanced fibrinolysis in this tissue. However, ascorbate did not affect increased PAI-1 mRNA in the liver (dominant source of soluble PAI-1 in systemic blood). Consistently, ascorbate affected neither elevated PAI-1 protein/enzymatic activity in septic liver nor lowered plasmin antiplasmin level in septic blood. Furthermore, hypocoagulability of septic blood revealed by thrombelastography and thrombin-induced PAI-1 release from isolated platelets (ex-vivo model of sepsis) were not affected by ascorbate. Based on the PAI-1 protein data, the present study does not support the hypothesis that ascorbate promotes fibrinolysis in sepsis.

Effects of Rosuvastatin on Fibrinolytic System of Human Umbilical Vein Endothelial Cells In Vitro

BackgroundBesides its lipid-lowering effect, rosuvastatin has an antithrombotic effect, the exact underlying mechanism of which is still unclear. The aim of this study was to investigate the effects of rosuvastatin on the fibrinolytic system, including tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) with its receptor (u-PAR) and plasminogen activator inhibitor-1 (PAI-1), in vascular endothelial cells exposed to oxidized low-density lipoprotein (oxLDL). MethodsHuman umbilical vein endothelial cells (HUVEC) were cultured and divided into 7 groups: control, rosuvastatin alone (10 nM), oxLDL alone (100mg/L), oxLDL plus rosuvastatin (0.1, 1.0 and 10 nM, respectively) and oxLDL plus rosuvastatin (10 nM) with mevalonate (100mM). The lactate dehydrogenase activity and concentrations of t-PA, u-PA, u-PAR and PAI-1 protein in culture medium were measured, whereas the expressions of t-PA, u-PA, u-PAR and PAI-1 mRNA in endothelial cells were detected by real-time polymerase chain reaction at 24 hours after treatment. ResultsCompared with the control group, oxLDL caused a significant increase in lactate dehydrogenase activity. It could reduce the expression of t-PA mRNA and protein (P < 0.05) and increase the expression of PAI-1 mRNA and protein (P < 0.05). Rosuvastatin could protect the endothelial cells, improve t-PA production and reduce PAI-1 production (P < 0.05), whether in unstimulated HUVEC or in HUVEC exposed to oxLDL. The effects of rosuvastatin on the fibrinolytic system could be reversed by mevalonate. No significant differences in u-PA and u-PAR production were seen among different groups. ConclusionsRosuvastatin has protective effects on oxLDL-induced damaged human vascular endothelial cells; its antithrombotic effects may be mediated by the regulation of the fibrinolytic system.

Renoprotective Effects of Direct Renin Inhibition in Glomerulonephritis

The development of glomerulonephritis causes glomerular injury and renal dysfunction and is thought to increase renin release, thus activating the renin-angiotensin system (RAS). The aims of this study were to demonstrate activation of the intrarenal RAs and determine the effects of direct renin inhibition (DRi) on the progression of glomerulonephritis. Rats were treated with anti-Thy1.1 antibody with or without DRI, aliskiren (30 mg/kg/d). In the glomerulonephritic rats, protein, microalbumin excretion levels, urinary angiotensinogen excretion, glomerular expansion score and intrarenal transforming growth factor-β and plasminogen activator inhibitor-1 mRNA levels were augmented compared with control rats; however, hypertension was not observed in the glomerulonephritic rats, and aliskiren treatment did not modify their blood pressure. The increases in urinary protein (94.7 ± 13.0 mg/d) and microalbumin (7.52 ± 2.6 mg/d) excretion were reduced by aliskiren (43.6 ± 4.5 mg/d of protein and 2.57 ± 0.7 mg/d of microalbumin). Furthermore, the progression of glomerular expansion and elevation of intrarenal transforming growth factor-β and plasminogen activator inhibitor-1 levels were prevented by aliskiren. Importantly, aliskiren suppressed the augmentation of urinary angiotensinogen levels, the increased angiotensinogen expression in the kidneys and the increases in Ang II levels in renal medulla induced by the anti-Thy1.1 antibody. These results suggest that DRI with aliskiren prevents intrarenal RAS activation leading to mitigation of the development of glomerulonephritis. In addition, the renoprotective effects of DRI on glomerulonephritis occur in a blood pressure-independent manner. Accordingly, treatment with aliskiren may be an effective approach to treat glomerulonephritis and other intrarenal RAS-associated kidney diseases.

PGE2 reduces MMP-14 and increases plasminogen activator inhibitor-1 in cardiac fibroblasts

Prostaglandin E2 (PGE2) is elevated during cardiac injury and we have previously shown that mice lacking the PGE2 EP4 receptor display dilated cardiomyopathy (DCM) with increased expression of the membrane type matrix metalloproteinase, MMP-14. We thus hypothesized that PGE2 regulates expression of MMP-14 and also affects fibroblast migration. Primary cultures of neonatal rat ventricular fibroblasts (NVFs) were used to test the effects of PGE2. Gene and protein expression was assessed by real time RT-PCR and Western blot, MMP activity was determined by zymography and migration of NVF was assessed by motility in a transwell system. PGE2 reduced expression of MMP-14 and these effects were antagonized by an EP4 antagonist. An EP4 agonist mimicked the effect of PGE2. PGE2 also increased mRNA and protein levels of plasminogen activator inhibitor-1 (PAI-1), an inhibitor of MMP activation. However, PGE2-stimulation of PAI-1 was mediated by the EP1/EP3 receptor and not EP4. Migration of NVF was assessed by motility in a transwell system. Treatment of NVFs with PGE2 reduced the number of cells migrating toward 10% FCS. Treatment with the EP2 agonist also reduced migration but did not affect MMP-14 expression or PAI-1. Our results suggest that PGE2 utilizes different receptors and mechanisms to ultimately decrease MMP expression and NVF migration.

Effects of inhaled nitric oxide on intrapulmonarynitric oxide production and expression of plasminogen activator inhibitor-1 in lipopolysaccharide-induced acute lung injury

Objective To explore the effects of inhaled nitric oxide(NO) on expression of plasminogen activator inhibitor-1 (PAI-1) mRNA and protein in the early-stage of experimental acute lung injury (ALI) in a rat model.And to investigate the relationship between endogenous NO system including inducible nitric oxide synthase (iNOS) and intrapulmonary NO production and expressions of PAI-1 in ALI. Methods In the study, endotoxemia followed by the second attack due to intratracheal injection of lipopolysaccharide (LPS) in rats caused ALI.Male SD rats aged 4-5 weeks (clean conventional rats, 180-200 g) were randomly assigned to 2 groups: saline control (C) group, LPS-treated (LPS) group, and the 2 groups were randomly allocated to subgroups exposed to air (A) or 20×10-6 NO.They were sacrificed for 24 h. Expressions of PAI-1 mRNA of the lung tissue were evaluated by real-time polymerise chain reaction; PAI-1 proteins were determined by immunohistochemistry.NO production in the lung tissues and pulmonary iNOS activity were measured.Meanwhile, histopathological lung injury scores were evaluated and modified martius acid fuchsin brilliant blue(MSB) stains was performed to evaluate fibrin of the lung tissues. Results At 24 h time point with intervention of iNO, PAI-1 mRNA and protein levels in LPS-NO subgroup were decreased compared with those in LPS-A subgroup(4.94±0.52 vs 5.56±0.27; 1.31±0.40 vs 1.69±0.16, all P<0.05). Meanwhile, iNOS activity and NO productions in LPS-NO subgroup were lower than those of LPS-A subgroup [(0.84±0.36)U/mg prot vs (2.30±0.25)U/mg prot; (1.90±0.84) μmol/g prot vs (3.38±0.73) μmol/g prot, all P<0.05]. iNOS activity had significant correlation with expression of PAI-1 mRNA and protein in lung tissue(r=0.481, P=0.005; r=0.667, P=0.000); NO production had significant correlation with expression of PAI-1 mRNA and protein in lung tissue(r=0.532, P=0.002; r=0.784, P=0.000). At 24 h time point, the histopathologic lung injury scores in LPS-NO subgroup were decreased in contrast to LPS-A subgroup (4.28±0.94 vs 6.12±1.51, P<0.05). Fibrin deposition eva-luated by modified MSB stains in LPS subgroups was found in alveolar space, lumen of blood vessel and mesenchymal; LPS subgroup with NO appeared a decreasing trend in contrast to LPS subgroup with air. Conclusions Inhaled nitric oxide of 20×10-6 can suppress elevated expression of PAI-1 in ALI induced by endotoxin.This inhaled NO can improve the imba-lance of plasminogen activation system and alleviate lung injury.Meanwhile, inhaled NO down-regulates intrapulmonary iNOS activity as well as endogenous NO productions in rats with 2 hits of LPS induced ALI.These changes also have a close correlation with down-regulation of PAI-1 mRNA and protein.Thus, regulation of endogenous NO system on the expression of PAI-1 will be the future direction of new therapies for ALI. Key words: Acute lung injury; Plasminogen activator inhibitor-1; Nitric oxide; Nitric oxide synthase