Increased expression of plasminogen activator inhibitor-1 (PAI-1) is associated with depression and depressive phenotype in C57Bl/6J mice.

Plasminogen activator inhibitor 1 (PAI-1), which is elevated in numerous disease states, has been implicated as a stress-related protein involved in the pathogenesis of depression. We measured PAI-1 in the plasma of healthy and depressed individuals and assessed plasminogen activator (PA) expression and regulation by PAI-1 in cultured normal human astrocytes (NHA). Elevated plasma PAI-1 levels were found in depressed patients. Brain tissues from depressed individuals also showed stronger expression of hippocampal PAI-1 by confocal imaging in comparison to healthy individuals. Using a lipopolysaccharide-induced inflammatory model of depression in mice, we measured PAI-1 in murine plasma and brain, by ELISA and immunohistochemistry, respectively. Similar elevations were seen in plasma but not in brain homogenates of mice exposed to LPS. We further correlated the findings with depressive behavior. Ex vivo experiments with NHA treated with proinflammatory cytokines implicated in the pathogenesis of depression showed increased PAI-1 expression. Furthermore, these studies suggest that urokinase-type plasminogen activator may serve as an astrocyte PA reservoir, able to promote cleavage of brain-derived neurotrophic factor (BDNF) during stress or inflammation. In summary, our findings confirm that derangements of PAI-1 variably occur in the brain in association with the depressive phenotype. These derangements may impede the availability of active, mature (m)BDNF and thereby promote a depressive phenotype.

Impact of Saskatoon berry powder on insulin resistance and relationship with intestinal microbiota in high fat-high sucrose diet-induced obese mice.

The present study examined the impact of Saskatoon berry powder (SBp) on insulin resistance, inflammation and intestinal microbiota in diet-induced obese mice. Male C57 BL/6 J mice were fed control diet, high fat-high sucrose (HFHS) diet or HFHS+5% SBp (HFHS+B) diet for 15 weeks. The composition of fecal bacterial community was characterized using the Illumina sequencing of V4 region of 16S rRNA gene. HFHS diet increased body weight, fasting plasma glucose, cholesterol, triglycerides, insulin, homeostatic model assessment-insulin resistance, monocyte adhesion, tumor necrosis factor-α, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, intracellular cell adhesion molecule-1, urokinase plasminogen activator and its receptor in plasma or aortae compared to the control diet. HFHS+B diet postponed the increase in body weight, suppressed HFHS diet-induced disorders in the metabolic and inflammatory variables. The ratio of Firmicutes/Bacteroidetes in the HFHS group was higher than that in the control group (P<.01), and that in the HFHS+B group was lower than that in the HFHS group (P<.05). The abundances of S24-7 family negatively correlated with body weight and tested metabolic or inflammatory variables. The results suggest that SBp attenuated HFHS diet-induced metabolic disorders and vascular inflammation in gut microbiota in mice.

Vehicle-dependent Effects of Sphingosine 1-phosphate on Plasminogen Activator Inhibitor-1 Expression.

AIM: Sphingosine 1-phosphate (S1P) has been suggested to be a positive regulator of plasminogen activator inhibitor 1 (PAI-1) in adipocytes, while some studies are not consistent with this prothrombotic property of S1P. Since S1P is bound to apolipoprotein M (apoM) on HDL or to albumin in plasma, we compared the properties of these two forms on the PAI-1 induction. METHODS: We investigated the associations of S1P, apoM, and PAI-1 concentrations in the plasma of normal coronary artery (NCA), stable angina pectoris (SAP), and acute coronary syndrome (ACS) subjects (n=32, 71, and 38, respectively). Then, we compared the effects of S1P with various vehicles on the PAI-1 expression in 3T3L1 adipocytes. We also investigated the modulation of the PAI-1 levels in mice infected with adenovirus coding apoM. RESULTS: Among ACS subjects, the PAI-1 level was positively correlated with the S1P level, but not the apoM level. In adipocytes, S1P bound to an apoM-rich vehicle induced PAI-1 expression to a lesser extent than the control vehicle, while S1P bound to an apoM-depleted vehicle induced PAI-1 expression to a greater extent than the control vehicle in 3T3L1 adipocytes. Additionally, apoM overexpression in mice failed to modulate the plasma PAI-1 level and the adipose PAI-1 expression level. S1P bound to albumin increased PAI-1 expression through the S1P receptor 2-Rho/ROCK-NFκB pathway. CONCLUSION: S1P bound to albumin, but not to apoM, induces PAI-1 expression in adipocytes, indicating that S1P can exert different properties on the pathogenesis of vascular diseases, depending on its vehicle.

Elevated Concentrations of SERPINE2/Protease Nexin-1 and Secretory Leukocyte Protease Inhibitor in the Serum of Patients with Papillary Thyroid Cancer.

Introduction. SERPINE2 and secretory leukocyte protease inhibitor (SLPI) are proteins with anticoagulant properties which could promote solid tumor growth. However, their role in the pathogenesis of thyroid cancer has not been determined. Materials and Methods. The aim of this study was to assess serum SERPINE2 and SLPI concentrations in a group of 36 patients with papillary thyroid cancer (PTC) and a group of 19 subjects with multinodular nontoxic goiter (MNG). The control group (CG) consisted of 20 healthy volunteers. Blood samples were collected one day before surgery. Serum SERPINE2 and SLPI concentrations were measured using specific ELISA methods. Results. Significantly higher concentrations of SERPINE2 and SLPI were found in patients with PTC as compared with MNG and controls. Positive correlation was found between SERPINE2 and SLPI concentrations in PTC patients. The levels of SERPINE2 and SLPI did not differ significantly between MNG and healthy controls. Conclusions. Our results indicate that SERPINE2 and SLPI play a significant role in the development of papillary thyroid cancer and imply that the evaluation of serum concentrations of both anticoagulant molecules may be considered as additional marker for the differentiation of malignancies during the preoperative diagnosis of patients with thyroid gland tumors.

Circadian fluctuations in circulating plasminogen activator inhibitor-1 are independent of feeding cycles in mice.

To evaluate the involvement of the day-night feeding cycle in the circadian regulation of circulating plasminogen activator inhibitor-1 (PAI-1) concentrations, mice were fed with a diet for eight hours during either daytime (DF) or nighttime (NF) for one week. The reversed feeding cycle did not affect the circadian phases of plasma PAI-1 levels as well as the nocturnal wheel-running activity, although the phase of Pai-1 mRNA expression was significantly advanced for 8.6 hours in the livers of DF, compared with NF mice. The day-night feeding cycle is not a critical Zeitgeber for circadian rhythm of circulating PAI-1.

Effects of a High-Fat or High-Sucrose Diet on Ultraviolet B Irradiation-Induced Carcinogenesis and Tumor Growth in Melanin-Possessing Hairless Mice.

We herein compared the effects of the chronic feeding of high-fat (HF), high-sucrose (HS), and low-fat/low-sucrose (control) diets on carcinogenesis following chronic ultraviolet B (UVB) irradiation in hairless mice. UVB irradiation-induced carcinogenesis was more prominent in HF diet-fed group than in control diet- and HS diet-fed groups. The HS diet group, as well as the HF diet one, showed tumor development and growth, increased skin matrix metalloproteinase (MMP) and blood plasminogen activator inhibitor-1 (PAI-1) levels, and decreased blood leptin and adiponectin levels after long-term UVB irradiation. These changes were smaller in the HS diet group than in the HF diet group. In addition, no difference was noted in the above changes between the control and HS diet groups. The increase induced in adipose tissue weight by the HF diet was markedly reduced by UVB irradiation. This result suggests that the abundant availability of lipids in hypertrophic adipose tissue may be related to tumor incidence and growth through increases in blood PAI-1 and skin MMP-9 expression levels and decreases in blood adiponectin levels by UVB irradiation. In conclusion, HF diet-induced hypertrophic adipose tissue is an important cancer risk factor that promotes UV irradiation-induced carcinogenesis and tumor growth.

Effects of a high-fat diet on spontaneous metastasis of Lewis lung carcinoma in plasminogen activator inhibitor-1 deficient and wild-type mice.

This study investigated the effects of a high-fat diet on spontaneous metastasis of Lewis lung carcinoma (LLC) in plasminogen activator inhibitor-1 deficient (PAI-1-/-) and wild-type mice. The high-fat diet increased the number of pulmonary metastases by 60% (p<0.01), tumor cross-sectional area by 82% (p<0.05) and tumor volume by 130% (p<0.05) compared to the AIN93G diet. Deficiency in PAI-1 reduced the number of metastases by 35% (p<0.01) compared to wild-type mice. In mice fed the high-fat diet, PAI-1 deficiency reduced tumor cross-sectional area by 52% (p<0.05) and tumor volume by 61% (p<0.05) compared to their wild-type counterparts; however, PAI-1 deficiency affected neither area nor volume in mice fed the AIN93G diet. Adipose and plasma concentrations of PAI-1 were significantly higher in high-fat fed wild-type mice than in their AIN93G-fed counterparts. Adipose and plasma PAI-1 were not detectable in PAI-1-/- mice regardless of the diet. Mice deficient in PAI-1 showed significantly greater plasma concentrations of monocyte chemotactic protein-1, tumor necrosis factor-α, leptin, vascular endothelial growth factor, tissue inhibitor of metalloproteinase-1 and insulin compared to wild-type mice, indicating a compensatory overproduction of inflammatory cytokines, angiogenic factors and insulin in the absence of PAI-1. We conclude that PAI-1 produced by the host, including that by adipose tissue, promotes high-fat enhanced metastasis of LLC.

Nocturnal light exposure alters hepatic Pai-1 expression by stimulating the adrenal pathway in C3H mice.

Recent studies have suggested the possibility that nocturnal light exposure affects many biological processes in rodents, especially the circadian rhythm, an endogenous oscillation of approximately 24 h. However, there is still insufficient information about the physiological effects of nocturnal light exposure. In this study, we examined the changes in gene expression and serum levels of plasminogen activator inhibitor-1 (PAI-1), a major component of the fibrinolytic system that shows typical circadian rhythmicity, in C3H/He mice. Zeitgeber time (ZT) was assessed with reference to the onset of light period (ZT0). Exposure to fluorescent light (70 lux) for 1 h in the dark period (ZT14) caused a significant increase in hepatic Pai-1 gene expression at ZT16. Serum PAI-1 levels also tended to increase, albeit not significantly. Expression levels of the typical clock genes Bmal1, Clock, and Per1 were significantly increased at ZT21, ZT16, and ZT18, respectively. Exposure to nocturnal light significantly increased plasma adrenalin levels. The effects of nocturnal light exposure on Pai-1 expression disappeared in adrenalectomized mice, although the changes in clock genes were still apparent. In conclusion, our results suggest that nocturnal light exposure, even for 1 h, alters hepatic Pai-1 gene expression by stimulating the adrenal pathway. Adrenalin secreted from the adrenal gland may be an important signaling mediator of the change in Pai-1 expression in response to nocturnal light exposure.

Consumption of a high-fat diet abrogates inhibitory effects of methylseleninic acid on spontaneous metastasis of Lewis lung carcinoma in mice.

We investigated the effect of dietary supplementation with selenium on spontaneous metastasis of Lewis lung carcinoma in mice fed a high-fat diet. Mice were fed a low-fat diet or that diet modified with 45% of calories from corn oil and supplemented with 0 or 2.5mg selenium/4029 kcal as methylseleninic acid. After 6 weeks, mice were each injected 2.5 × 10(5) Lewis lung carcinoma cells subcutaneously. The resulting primary tumor was removed surgically 10 days later; the experiment was terminated after an additional 10 days. High-fat feeding increased pulmonary metastases by 17% compared to the low-fat diet (P < 0.01). Selenium supplementation reduced the metastases by 11% compared to nonsupplemented controls (P < 0.05); the reduction was less for animals fed the high-fat diet (5%) than for those fed the low-fat diet (18%). Supplemental Se lowered plasma concentrations of proteases (urokinase plasminogen activator, P < 0.01; matrix metalloproteinase-9, P < 0.05) and angiogenic factors (vascular endothelial growth factor, P < 0.01; tissue inhibitor of metalloproteinase-1, P < 0.01) compared to nonsupplemented controls. High-fat feeding increased plasma concentrations of adipokines plasminogen activator inhibitor-1, monocyte chemotactic protein-1, tumor necrosis factor-α, and leptin regardless of the level of dietary selenium; supplemental selenium lowered plasma concentrations of plasminogen activator inhibitor-1 (P ≤ 0.05) and monocyte chemotactic protein-1 (P ≤ 0.05) in low-fat fed mice but not in high-fat fed mice. These results indicate that consumption of a high-fat diet abrogated the antimetastatic effects of selenium by increasing the expression of adipose-derived inflammatory cytokines.

Protective effect of magnesium lithospermate B against dextran sodiumsulfate induced ulcerative colitis in mice.

Anti-platelet drugs have been used to treat inflammatory bowel disease. In this study, we observed the therapeutic effects of magnesium lithospermate B, a main component of salvianolate, on colitis induced by dextran sodiumsulfate (DSS). Colitis was induced by 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (60-240mg/kg) was given by subcutaneous injection for 2 weeks. Then, mice were sacrificed; serum and colon tissues were collected for biomarker assay, histological examination, immunohistochemical study and real-time quantitative polymerase chain reaction. DSS induced gross bleeding, inflammation, crypt damage and mucosal damage in colon. Treatment with magnesium lithospermate B could reduce colon inflammation induced by DSS. Magnesium lithospermate B could reverse the high CD40/CD40L expression and hypercoagulable state induced by DSS in colon. This study showed that magnesium lithospermate B could be used to treat colitis. The protective effects of magnesium lithospermate B may be due to its effects on CD40/CD40L expression and blood clotting status.

Chronic circadian clock disruption induces expression of the cardiovascular risk factor plasminogen activator inhibitor-1 in mice.

Links between shift work and increases in metabolic risk factors for cardiovascular diseases have been documented in detail, although the underlying causes remain obscure. Plasminogen activator inhibitor-1 (PAI-1) is a key regulator of fibrinolysis that is also associated with an increased risk of cardiovascular diseases. We examined the effect of experimental chronic circadian clock disruption on PAI-1 expression in mice. Mice were exposed to chronic phase shifts and fed with a high-fat/high-sucrose diet. Chronic phase shifts resulted in increased plasma PAI-1 level through inducing PAI-1 mRNA expression and decreasing tissue-type plasminogen activator (tPA) mRNA expression in the liver. Chronic circadian clock disruption might induce hypofibrinolysis and increase the risk of cardiovascular events by inducing the PAI-1 gene expression in obese individuals.

Oral carcinogenesis is not achieved in different carcinogen-treated PAI-1 transgenic and wild-type mouse models.

AIM: In an effort to assess the role of plasminogen activator inhibitor-1 (PAI-1) in oral squamous cancer development and progression, two different carcinogen treatment protocols were conducted. MATERIALS AND METHODS: Protocol I included mice from a PAI-1 transgenic (Tg) breed (n=56) and their wild-type (WT) counterparts (n=56), divided into one control group and two main experimental groups, treated with 7,12-dimethylbenz[a]anthracene (DMBA) for 8 and 16 weeks, respectively. Protocol II included the same number and types of animals and groups, which were similarly treated with 4-Nitroquinoline 1-oxide (4-NQO) in drinking water. Two drugs that affect plasma PAI-1 levels, enalapril and pravastatin, were administered to certain subgroups of animals in both protocols. RESULTS: None of the animals developed macroscopically-visible oral cancer lesions. Eleven animals under Protocol I and 52 animals under Protocol II died. Skin lesions were noted only in DMBA-treated animals (n=9). Almost all animals administered with 4-NQO developed alopecia and lost weight, while two of them developed stomach tumours, and one female mouse developed a large ovarian cyst. CONCLUSION: Transgenic mice may respond differently when used in well-established carcinogen models and oral carcinogenesis is hard to achieve in these rodents.

The vitronectin-binding function of PAI-1 exacerbates lung fibrosis in mice.

Plasminogen activator inhibitor-1 (PAI-1) is increased in the lungs of patients with pulmonary fibrosis, and animal studies have shown that experimental manipulations of PAI-1 levels directly influence the extent of scarring that follows lung injury. PAI-1 has 2 known properties that could potentiate fibrosis, namely an antiprotease activity that inhibits the generation of plasmin, and a vitronectin-binding function that interferes with cell adhesion to this extracellular matrix protein. To determine the relative importance of each PAI-1 function in lung fibrogenesis, we administered mutant PAI-1 proteins that possessed either intact antiprotease or vitronectin-binding activity to bleomycin-injured mice genetically deficient in PAI-1. We found that the vitronectin-binding capacity of PAI-1 was the primary determinant required for its ability to exacerbate lung scarring induced by intratracheal bleomycin administration. The critical role of the vitronectin-binding function of PAI-1 in fibrosis was confirmed in the bleomycin model using mice genetically modified to express the mutant PAI-1 proteins. We conclude that the vitronectin-binding function of PAI-1 is necessary and sufficient in its ability to exacerbate fibrotic processes in the lung.