Involvement of S100A4/Mts1 and associated proteins in the protective effect of fluoxetine against MCT - Induced pulmonary hypertension in rats.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a complex pulmonary vasculature disease characterized by remodeling of the pulmonary vessels and a persistent increase in the pulmonary vascular resistance (PVR) with a poor prognosis. Serotonin increases the expression of S100A4/Mts1, which in turn stimulates the proliferation and migration of human pulmonary artery smooth muscle cells through the interaction with RAGE (receptor for advanced glycation end products) and thus S100A4/Mts1 has been implicated in the development of PAH in vitro. Fluoxetine, a selective serotonin re-uptake inhibitor has been shown to protect against PAH. The current study was designed to test whether S100A4 and its associated proteins connected in the development of PAH in vivo as well as to investigate the involvement of those proteins in the protective effect of fluoxetine against PAH. METHODS: MCT-induced PAH models were established in Wistar rats by a single intraperitoneal injection of MCT (60 mg/kg). Fluoxetine (2 and 10 mg/kg/day) was intragastrically administered once a day for 3 weeks along with controls. The detection methods followed include Hematoxylin and Eosin (H&E) staining, immunohistochemistry, western blotting and real-time reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: MCT induced pulmonary hypertension, pulmonary vascular remodeling, and right ventricular hypertrophy significantly increased the expressions of S100A4 and RAGE in the pulmonary arteries, lungs and right ventricle (RV). Fluoxetine dose-dependently inhibited MCT-induced pulmonary arterial hypertension, pulmonary vascular remodeling, and right ventricular hypertrophy and reduced the S100A4 and RAGE. Further analysis revealed that fluoxetine alleviated both the increase of p53, MMP13, MMP2 and MMP9 and the decrease of pp53Ser15 and MDM2 in lungs and RV tissues of MCT-induced PAH rats. CONCLUSION: From the present investigation it could be concluded that S100A4/Mts1 and its associated proteins are involved in the evolution of MCT-induced PAH in rats and fluoxetine inhibits MCT-induced PAH in rats mainly through S100A4/RAGE signaling axis and involved factors.

Role of Noncoding RNA in Pulmonary Arterial Hypertension and Potential Drug Therapeutic Target.

Pulmonary arterial hypertension (PAH) is a devastating disease without effective drugs available for its treatment. An in-depth exploration of the pathogenesis of PAH, as well as inquiry into potential therapeutic targets, remains an urgent issue. Non-coding RNAs (ncRNAs) have arisen as key players in malignant tumors, cardiovascular diseases and more recently in PAH progression and development. Network pharmacology is a new discipline based on system biology, which can predict potential therapeutic targets in diseases regulated by multiple genes. In this review, we discuss the current knowledge of ncRNAs and network pharmacology regulated genes involved in PAH, as well as the search for potential drug targets for PAH.

The protective effects of PCPA against monocrotaline-induced pulmonary arterial hypertension are mediated through the downregulation of NFAT-1 and NF-κB.

Inflammation and remodeling play a role in the pathogenesis of pulmonary arterial hypertension (PAH). Nuclear factor-κB (NF-κB) and nuclear factor of activated T cells-1 (NFAT-1) participate in inflammation and remodeling in a number of diseases. As a tryptophan hydroxylase inhibitor, 4-chloro-DL-phenylalanine (PCPA) had been reported to exert anti-inflammatory and remodeling effects. Therefore, we hypothesized that PCPA may attenuate monocrotaline (MCT)-induced PAH through the NFAT-1 and NF-κB signaling pathways. In order to confirm our hypothesis, we divided 68 Sprague-Dawley male rats into 4 groups as follows: the control, MCT, MCT + P1 and MCT + P2 groups. MCT was administered at a dose of 60 mg/kg once via intraperitoneal injection. PCPA was administered via intraperitoneal injection at a dose of 50 or 100 mg/kg once daily for 21 consecutive days. We then measured the hemodynamic index and morphological analysis was carried out on the lung tissues. Western blot analysis and immunohistochemistry were used to examine the levels of NFAT-1 and NF-κB p-65. The expression levels of phosphorylated inhibitor of NF-κB kinase (p-IKK), IKK, phosphorylated extracellular signal­regulated kinase (p-ERK), ERK, intercellular adhesion molecule-1 (ICAM-1) and inter-leukin-6 (IL-6) were examined by western blot analysis. MCT was found to significantly induce PAH, with inflammation and remodeling of the lung tissues. This was associatd with an increased expression of NFAT-1, p-IKK, p-ERK and nuclear p65. PCPA significantly attenuated MCT-induced inflammation and arterial remodeling, and decreased the expression of NFAT-1, as well as that of relevant proteins of the NF-κB signaling pathway. The above-mentioned findings suggest that the inhibitory effects of PCPA on MCT-induced inflammation and arterial remodeling are related to the downregulation of the NFAT-1 and NF-κB signaling pathways in rats with PAH.

Suppression of nuclear factor erythroid­2­related factor 2­mediated antioxidative defense in the lung injury induced by chronic exposure to methamphetamine in rats.

The imbalance between oxidative stress and antioxidant defense is important in the pathogenesis of lung diseases. Nuclear factor erythroid­2­related factor 2 (Nrf2) is a key transcriptional factor that regulates the antioxidant response. The purpose of the present study was to investigate whether Nrf2­mediated antioxidative defense is involved in methamphetamine (MA)­induced lung injury in rats. Following establishment of chronic MA toxicity in rats, Doppler ultrasonic detection was used to measure the changes of physiological indexes, followed by hematoxylin and eosin staining, ELISA and western blot analysis. MA was demonstrated to increase the heart rate and peak blood flow velocity of pulmonary arterial valves and to decrease the survival rate of rats, and resulted in lung injury characterized by perivascular exudates, airspace edema, slight hemorrhage and inflammatory cell infiltration. MA significantly inhibited the expression of nuclear Nrf2 protein and its target genes (glutamate­cysteine ligase catalytic subunit C and heme oxygenase­1), and dose­dependently reduced glutathione (GSH) levels and the ratio of GSH/oxidized glutathione, accompanied by increases in reactive oxygen species (ROS) levels in rat lungs. Linear regression analysis revealed that there was a positive correlation between lung ROS level and lung injury indexes. These findings suggested that chronic exposure to MA led to lung injury by suppression of Nrf2­mediated antioxidative defense, suggesting that Nrf2 may be an important therapeutic target for MA­induced chronic lung toxicity.

TBHQ Alleviated Endoplasmic Reticulum Stress-Apoptosis and Oxidative Stress by PERK-Nrf2 Crosstalk in Methamphetamine-Induced Chronic Pulmonary Toxicity.

Methamphetamine (MA) leads to cardiac and pulmonary toxicity expressed as increases in inflammatory responses and oxidative stress. However, some interactions may exist between oxidative stress and endoplasmic reticulum stress (ERS). The current study is designed to investigate if both oxidative stress and ERS are involved in MA-induced chronic pulmonary toxicity and if antioxidant tertiary butylhydroquinone (TBHQ) alleviated ERS-apoptosis and oxidative stress by PERK-Nrf2 crosstalk. In this study, the rats were randomly divided into control group, MA-treated group (MA), and MA plus TBHQ-treated group (MA + TBHQ). Chronic exposure to MA resulted in slower growth of weight and pulmonary toxicity of the rats by increasing the pulmonary arterial pressure, promoting the hypertrophy of right ventricle and the remodeling of pulmonary arteries. MA inhibited the Nrf2-mediated antioxidative stress by downregulation of Nrf2, GCS, and HO-1 and upregulation of SOD2. MA increased GRP78 to induce ERS. Overexpression and phosphorylation of PERK rapidly phosphorylated eIF2α, increased ATF4, CHOP, bax, caspase 3, and caspase 12, and decreased bcl-2. These changes can be reversed by antioxidant TBHQ through upregulating expression of Nrf2. The above results indicated that TBHQ can alleviate MA-induced oxidative stress which can accelerate ERS to initiate PERK-dependent apoptosis and that PERK/Nrf2 is likely to be the key crosstalk between oxidative stress and ERS in MA-induced chronic pulmonary toxicity.

Endoplasmic reticulum stress and apoptosis via PERK-eIF2α-CHOP signaling in the methamphetamine-induced chronic pulmonary injury.

Methamphetamine (MA) leads to multiple organs lesions and apoptosis. The aim of this study is to investigate if endoplasmic reticulum stress (ERS) - initiated apoptosis is involved in the chronic pulmonary injury induced by MA. In this study, rats were divided into a control group, methamphetamine 5mg/kg group and methamphetamine 10mg/kg group. This study found that the protein level of GRP78 is higher in M10 group than in control group. PERK signaling and the relevant apoptosis factors were also activated. Morphological measurements showed that protein BAX and CHOP accumulated in the alveolar epithelium and the alveolar walls with epithelium were damaged and that the number of pulmonary alveoli decreased. The findings showed that ERS and PERK pathway are activated and eventually lead to apoptosis. Severe ERS mediated the apoptosis of alveolar epithelium cells as well as decreasing numbers of pulmonary alveoli.

PCPA protects against monocrotaline-induced pulmonary arterial remodeling in rats: potential roles of connective tissue growth factor.

The purpose of this study was to investigate the mechanism of monocrotaline (MCT)-induced pulmonary artery hypertension (PAH) and determine whether 4-chloro-DL-phenylalanine (PCPA) could inhibit pulmonary arterial remodeling associated with connective tissue growth factor (CTGF) expression and downstream signal pathway. MCT was administered to forty Sprague Dawley rats to establish the PAH model. PCPA was administered at doses of 50 and 100 mg/kg once daily for 3 weeks via intraperitoneal injection. On day 22, the pulmonary arterial pressure (PAP), right ventricle hypertrophy index (RVI) and pulmonary artery morphology were assessed and the serotonin receptor-1B (SR-1B), CTGF, p-ERK/ERK were measured by western blot or immunohistochemistry. The concentration of serotonin in plasma was checked by ELISA. Apoptosis and apoptosis-related indexes were detected by TUNEL and western blot. In the MCT-induced PAH models, the PAP, RVI, pulmonary vascular remodeling, SR-1B index, CTGF index, anti-apoptotic factors bcl-xl and bcl-2, serotonin concentration in plasma were all increased and the pro-apoptotic factor caspase-3 was reduced. PCPA significantly ameliorated pulmonary arterial remodeling induced by MCT, and this action was associated with accelerated apoptosis and down-regulation of CTGF, SR-1B and p-ERK/ERK. The present study suggests that PCPA protects against the pathogenesis of PAH by suppressing remodeling and inducing apoptosis, which are likely associated with CTGF and downstream ERK signaling pathway in rats.

Fluoxetine protects against methamphetamine­induced lung inflammation by suppressing oxidative stress through the SERT/p38 MAPK/Nrf2 pathway in rats.

Methamphetamine (MA) abuse is a major public health and safety concern throughout the world and a growing burden on healthcare costs. The purpose of the present study was to investigate the protective effect of fluoxetine against MA­induced chronic pulmonary inflammation and to evaluate the potential role of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidative stress. Wistar rats were divided into control, MA and two fluoxetine­treated groups. Rats in the MA and the two fluoxetine­treated groups were treated daily with intraperitoneal injection of 10 mg/kg MA twice daily. Rats in the two fluoxetine­treated groups were injected intragastrically with fluoxetine (2 and 10 mg/kg) once daily, respectively. After 5 weeks, the rats were euthanized and hematoxylin and eosin staining, immunohistochemistry, western blot analysis and redox assay were performed. It was demonstrated that chronic exposure to MA can induce pulmonary inflammation in rats, with the symptoms of inflammatory cell infiltration, crowded lung parenchyma, thickened septum and a reduced number of alveolar sacs. Fluoxetine attenuated pulmonary inflammation and the expression of interleukin­6 and tumor necrosis factor­α in rat lungs. Fluoxetine inhibited MA­induced increases in the expression levels of serotonin transporter (SERT) and p­p38 mitogen­activated protein kinase (MAPK), and reversed the MA­induced decrease in nuclear Nrf2 and human heme oxygenase­1 in lungs. Fluoxetine at 10 mg/kg significantly reversed the reduced glutathione (GSH) level, the ratio of GSH/oxidized glutathione, and the reactive oxygen species level in rat lungs from the MA group. These findings suggested that fluoxetine, a SERT inhibitor, has a protective effect against MA­induced lung inflammation by suppressing oxidative stress through the SERT/p38 MAPK/Nrf2 pathway in rats.

[Clinical outcome of arthroscopic excision of the os subfibulare in ankle pain].

OBJECTIVE: To evaluate the clinical effect of arthroscopic excision of the os subfibulare in anterior-lateral ankle pain. METHODS: From December 2005 to Augest 2014, 16 patients suffering from pain associated with an os subfibulare in the anterior-lateral side of their ankles were reviewed. Among the patients,11 patients were male and 5 were female, with a mean age of (33.5 ± 15.6) years old. The mean maximum diameter of os subfibulare was (0.70 ± 0.26) cm. All the patients underwent excision of the osseous fragments, and had anatomic reconstruction of the anterior talofibular ligament if the anterior-lateral ankle was instable. The average follow-up period was (18.0 ± 4.5) months. To analyze the surgical outcome, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot pain and function scales,visual analogue scale (VAS) and Tegner activity scale were assessed preoperatively and postoperatively. RESULTS: AOFAS scales were preoperative 60.15 ± 14.52 and postoperative 92.35 ± 5.73. There was a significant difference between them (t = -8.251, P = 0.000). The mean VAS score were preoperative 7.35 ± 0.46 and postoperative 2.45 ± 0.98. Statistical significance was also notable (t = 18.105, P = 0.000). Tegner score was significantly increased from preoperative 2.87 ± 1.12 to postoperative 5.78 ± 1.06 (t= -7.548, P = 0.000). CONCLUSION: Irrespective of the size of os subfibulare, in patients with pain or instability associated with the os subfibulare, arthroscopic excision combined with reconstruction of ther anterior talofibular ligament or not was effective in restoring ankle function and eliminating pain.

4-Chloro-DL-phenylalanine protects against monocrotaline­induced pulmonary vascular remodeling and lung inflammation.

The present study was performed to investigate the effects of 4-chloro-DL-phenylalanine (PCPA), a tryptophan hydroxylase (Tph) inhibitor (TphI), on pulmonary vascular remodeling and lung inflammation in monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) in rats. Animal models of PAH were established using Sprague-Dawley (SD) rats by a single intraperitoneal injection of MCT (60 mg/kg). PCPA (50 or 100 mg/kg/day) was administered to the rats with PAH. On day 22, hemodynamic measurements and morphological observations of the lung tissues were performed. The levels of Tph-1 and serotonin transporter (SERT) in the lungs were analyzed by immunohistochemistry and western blot analysis. The expression of matrix metalloproteinase (MMP)-2 and MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 and inflammatory cytokines were assayed by western blot analysis. The activity of MMP-2 and MMP-9 was evaluated by gelatin zymography (GZ). MCT markedly promoted PAH, increased the right ventricular hypertrophy index, pulmonary vascular remodeling, lung inflammation and mortality, which was associated with the increased expression of Tph-1, SERT, MMP-2/-9, TIMP-1/-2 and inflammatory cytokines. PCPA markedly attenuated MCT-induced pulmonary vascular remodeling and lung inflammation, inhibited the expression of Tph-1 and SERT and suppressed the expression of MMP-2/-9, TIMP-1/-2, interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and intercellular adhesion molecule-1 (ICAM-1). These findings suggest that the amelioration of MCT-induced pulmonary vascular remodeling and lung inflammation by PCPA is associated with the downregulation of Tph-1, SERT, MMP/TIMP and inflammatory cytokine expression in rats.

Fluoxetine attenuates chronic methamphetamine-induced pulmonary arterial remodelling: possible involvement of serotonin transporter and serotonin 1B receptor.

Epidemiological data have shown that methamphetamine (MA) abuse significantly increases the risk of developing pulmonary arterial hypertension (PAH). To investigate whether MA could induce PAH and its possible mechanism, rats were exposed daily to MA for 5 weeks in the absence or presence of fluoxetine. The results showed that the pulmonary arterial pressure was not significantly increased, but the pulmonary arterial remodelling was markedly developed in the MA exposure group. The protein expressions of the serotonin transporter (5-HTT) and 5-HT(1B) receptor were increased in the lungs and in the pulmonary arteries of MA-treated rats. Fluoxetine attenuated the pulmonary arterial remodelling and down-regulated the protein expression of 5-HTT and 5-HT(1B) receptor in pulmonary arteries of MA-treated rats. These findings suggest that fluoxetine has a novel potential suppressive effect on the chronic MA-induced pulmonary vascular remodelling and also suggest that 5-HTT and 5-HT(1B) receptor may be involved as part of its mechanism.

Fluoxetine inhibits monocrotaline-induced pulmonary arterial remodeling involved in inhibition of RhoA-Rho kinase and Akt signalling pathways in rats.

Activation of the small GTPase Ras homolog gene family member A (RhoA) and Rho-associated kinase (ROCK) are important in the pathogenesis of pulmonary arterial hypertension (PAH). Selective serotonin reuptake inhibitors inhibit activation of RhoA and ROCK in vitro, and ameliorate PAH and pulmonary arterial remodeling in vivo. However, little is known about whether the RhoA-ROCK signalling pathway is involved in the treatment of PAH with fluoxetine in vivo. The aim of the present study was to investigate the involvement of the RhoA-ROCK signalling pathway in the protective effect of the selective serotonin reuptake inhibitor fluoxetine against monocrotaline (MCT)-induced pulmonary arterial remodeling. MCT was applied to establish PAH in male Wistar rats. Fluoxetine was administered by gastric gavage once a day for 21 d. The results showed that MCT induced pulmonary arterial remodeling, raised the serotonylation and membrane translocation of RhoA in the lungs, and increased serotonin transporter (5-HTT), RhoA, and ROCK2 expression, and extracellular signal-regulated kinase (ERK) and Akt phosphorylation in the pulmonary arteries and the lungs. Fluoxetine markedly inhibited these MCT-induced changes. The findings suggest that fluoxetine inhibits MCT-induced pulmonary arterial remodeling in rats by inhibition of the RhoA-ROCK and Akt signalling pathways.

Fluoxetine protects against monocrotaline-induced pulmonary arterial remodeling by inhibition of hypoxia-inducible factor-1α and vascular endothelial growth factor.

The selective serotonin re-uptake inhibitor fluoxetine has been shown to protect against monocrotaline (MCT)-induced pulmonary hypertension in rats. To investigate the possible role of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in mediating this protective effect, MCT-treated rats were administered fluoxetine by gavage, at doses of 2 mg/kg body mass or 10 mg/kg once daily for 3 weeks. Changes in pulmonary hemodynamic parameters, pulmonary artery morphologies, and expressions of HIF-1α and VEGF were assessed. Fluoxetine at the 10 mg/kg dose, but not at the 2 mg/kg dose, attenuated the effects of MCT on pulmonary artery pressure, right ventricle index, and medial wall thickness. In addition, 10 mg/kg fluoxetine mitigated the MCT-induced up-regulation of HIF-1α and VEGF protein and reactive oxygen species (ROS) in the lungs. This dosage also decreased pERK1/2 levels and inhibited proliferation of pulmonary arterial smooth muscle cells in MCT-treated rats. In conclusion, fluoxetine can protect against MCT-induced pulmonary arterial remodeling, which linked to reduced ROS generation and decreased HIF-1α and VEGF protein levels via the ERK1/2 phosphorylation pathway.

Involvement of BMPR2 in the protective effect of fluoxetine against monocrotaline-induced endothelial apoptosis in rats.

Mutations in bone morphogenetic protein (BMP) receptor II (BMPR2) are associated with the apoptosis of the pulmonary artery endothelial cells and the loss of the pulmonary small vessels. The present study was designed to investigate the involvement of BMPR2 in the protective effect of fluoxetine against monocrotaline (MCT)-induced endothelial apoptosis in rats. Models of pulmonary arterial hypertension in rats were established by a single intraperitoneal injection of MCT (60 mg/kg). Fluoxetine (2 and 10 mg/kg) was intragastrically administered once a day. After 21 days, MCT caused pulmonary hypertension, right ventricular hypertrophy, and pulmonary vascular remodeling and significantly reduced the BMPR2 expression in lungs and pulmonary arteries. Fluoxetine dose-dependently inhibited MCT-induced pulmonary arterial hypertension and effectively protected the lungs against MCT-induced endothelial apoptosis, reduction in the number of alveolar sacs, and loss of the pulmonary small vessels. Fluoxetine reversed the expression of cyclic guanosine 3',5'-monophosphate-dependent kinase І, BMPR2, phospho-Smad1, ß-catenin, and reduced the expression of caspase 3 in rat lungs. These findings suggest that BMPR2 is probably involved in the protective effect of fluoxetine against MCT-induced endothelial apoptosis in rats.

Downregulation of osteopontin is associated with fluoxetine amelioration of monocrotaline-induced pulmonary inflammation and vascular remodelling.

1. Osteopontin (OPN) has emerged as a key factor in inflammatory activation and cardiovascular remodelling. The aim of the present study was to investigate the involvement of OPN in fluoxetine amelioration of monocrotaline (MCT)-induced pulmonary inflammation and vascular remodelling in rats. 2. Wistar rats were divided into control, MCT and two fluoxetine-treated groups. Pulmonary arterial hypertension (PAH) was induced by a single injection of MCT (60 mg/kg, i.p.). Fluoxetine (2 and 10 mg/kg) was administered via the intragastric route once a day for 21 days. On Day 22, pulmonary haemodynamic measurements were undertaken, followed by ELISA, western blotting and immunohistochemistry. 3. Monocrotaline caused pulmonary inflammation and vascular remodelling and significantly enhanced OPN expression in the plasma, lungs and pulmonary arteries. Fluoxetine decreased pulmonary arterial pressure and ameliorated pulmonary inflammation and pulmonary vascular remodelling. At 10 mg/kg, fluoxetine significantly inhibited MCT-induced increases in the expression of serotonin transporter (SERT) and phosphorylated extracellular signal-regulated kinase 1/2 and downregulated the expression of OPN, macrophage inflammatory protein-1ß and matrix metalloproteinase 2/tissue inhibitor of metalloproteinase 2. Although 2 mg/kg fluoxetine tended to ameliorate some MCT-induced changes in the lung, the differences did not always reach statistical significance. Linear regression analysis showed that there was a positive correlation between plasma OPN concentrations and mean pulmonary arterial pressure, as well as percentage medial wall thickness and percentage wall area in the pulmonary artery. 4. In conclusion, the amelioration by fluoxetine of MCT-induced pulmonary inflammation and vascular remodelling is associated with downregulation of OPN expression in rats.

Fluoxetine inhibited extracellular matrix of pulmonary artery and inflammation of lungs in monocrotaline-treated rats.

AIM: To investigate the effects of the selective serotonin reuptake inhibitor (SSRI) fluoxetine on extracellular matrix (ECM) remodeling of the pulmonary artery and inflammation of the lungs in pulmonary arterial hypertension (PAH) induced by monocrotaline in rats. METHODS: MCT-induced chronic PAH was established in Wistar rats. After treatment with fluoxetine for 3 weeks, pulmonary hemodynamic measurement and morphological investigation of lung tissues were undertaken. The main components of the ECM, elastin and collagen, were detected using Van Gieson stain and Orcein stain, respectively, or using Victoria-ponceau's double stain. The ECM proteolytic enzymes matrix metalloproteinase (MMP)-2 and MMP-9, and the tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2, were detected by Western blot. Inflammation of lung tissue was assayed using lung morphology and inflammatory cytokine expression. RESULTS: Fluoxetine (2 and 10 mg/kg) significantly inhibited MCT-induced PAH, attenuated pulmonary arterial muscularization and ECM remodeling, and decreased MMP/TIMP expression. Fluoxetine also suppressed inflammatory responses in lung tissue and inhibited the expression of the inflammatory cytokines interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), monocyte chemotactic protein (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). CONCLUSION: Fluoxetine inhibited MCT-induced ECM remodeling of the pulmonary artery and inflammation of lung tissue. These effects were related to its inhibition on MMPs/TIMPs and cytokine productions.

Fluoxetine protects against monocrotaline-induced pulmonary arterial hypertension: potential roles of induction of apoptosis and upregulation of Kv1.5 channels in rats.

1. Suppressing apoptosis and downregulating K(+) channels in pulmonary artery smooth muscle cells (PASMC) have been implicated in the development of pulmonary vascular medial hypertrophy and pulmonary arterial hypertension (PAH). Previous studies have shown that selective serotonin re-uptake inhibitors (SSRIs) protected against PAH. The aim of the present study was to investigate the involvement of Kv1.5 channels and apoptosis in the protective effect of the SSRI fluoxetine against PAH. 2. Monocrotaline (MCT) was used to establish PAH in Wistar rats. Fluoxetine (2 and 10 mg/kg per day) was administered by gavage once a day for 3 weeks. Three weeks after the induction of PAH by MCT, pulmonary haemodynamic measurements and pulmonary artery morphological assessments were undertaken, along with detection of apoptosis and Kv1.5. 3. Fluoxetine (2 and 10 mg/kg per day) decreased pulmonary artery pressure, reduced the right ventricular index and inhibited the increase in medial wall thickness of pulmonary arteries in established PAH. Fluoxetine (10 mg/kg per day) reduced the expression of Bcl-2 and Bcl-xL protein, increased the expression of cleaved caspase 3 protein and enhanced the expression of Kv1.5 protein and mRNA in pulmonary arteries. Furthermore, fluoxetine (10 mg/kg per day) significantly suppressed proliferation and enhanced apoptosis of PASMC in MCT-induced PAH. 4. In conclusion, fluoxetine protects against MCT-induced PAH by suppressing PASMC proliferation, inducing PASMC apoptosis and upregulating Kv1.5 channels.

[Changes of pulmonary artery protein kinase C activity in rats with chronic inflammatory pulmonary hypertension].

OBJECTIVE: To observe the changes in pulmonary artery protein kinase C (PKC) activity in rats with chronic inflammatory pulmonary hypertension (PHT). METHODS: Chronic inflammatory PHT was induced in rats with monocrotaline. The PKC activities in the rat pulmonary arteries were measured by radioactive assay during the development of PHT. RESULTS: With the development of chronic inflammatory PHT, the total and cytosolic fractions of PKC activity in PHT rat pulmonary arteries increased initially with subsequent decrease (Plt;0.05), but the membranous fraction of PKC activity and the membrane-to-cytosol PKC activity ratio increased continuously (P<0.05). CONCLUSION: The up-regulation of PKC activity and the translocation of PKC might be associated with the development of chronic inflammatory PHT in rats.

Sertraline protects against monocrotaline-induced pulmonary hypertension in rats.

1. Serotonin (5-HT), as a type of mitogen for smooth muscle cells, plays an important role in the development of pulmonary hypertension. It is known that selective serotonin re-uptake inhibitors (SSRI) inhibit 5-HT internalization. Therefore, the aim of the present study was to investigate the protective effect and mechanism of the SSRI sertraline against pulmonary hypertension. 2. Monocrotaline (MCT)-induced chronic 'inflammatory' pulmonary hypertension in Wistar rats was established. Pulmonary haemodynamic measurement and lung tissue morphological investigations were undertaken. Serotonin transporter (SERT) mRNA was assayed by reverse transcription-polymerase chain reaction (RT-PCR). 3. The results showed that pulmonary artery pressure (PAP) was significantly increased by MCT treatment from 12.6 +/- 2.1 to 20.1 +/- 3.4 mmHg (P < 0.01 vs control) and sertraline attenuated the MCT-induced increase in PAP from 20.1 +/- 3.4 to 16.4 +/- 1.8 mmHg (P < 0.05 vs MCT). The right ventricular index was increased in the MCT-treated group from 0.32 +/- 0.04 to 0.51 +/- 0.09 (P < 0.01 vs control) and was reduced to 0.42 +/- 0.04 by sertraline (P < 0.05 vs MCT). The degree of muscularization of the pulmonary artery in the MCT-treated group was significantly higher than control (P < 0.01) and was decreased by sertraline (P < 0.01 vs MCT). The RT-PCR assay showed that MCT increased SERT mRNA expression from 0.86 +/- 0.08 to 0.99 +/- 0.06 (P < 0.05 vs control), which was attenuated by sertraline (0.82 +/- 0.09; P < 0.05 vs MCT). 4. In conclusion, the SSRI sertraline protects against MCT-induced pulmonary hypertension by decreasing PAP, right ventricular index and pulmonary artery remodelling, which may be related to a reduction in SERT mRNA.

Antagonism of transforming growth factor-Beta signaling inhibits fibrosis-related genes.

In the fibrotic process, the transforming growth factor-beta1 (TGF-beta1)/Smad3 (Sma- and Mad-related protein 3) signaling plays a central role. To screen for antagonists of TGF-beta1/Smad3 signaling and to investigate their effects on the genes related to fibrosis, we construct a molecular model with a luciferase reporter gene. Results showed that both SB-431542 [4-(5-benzo[1,3]dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)-benzamide] and small interference RNA (siRNA) against Smad3 could dose-dependently suppress the reporter gene. More importantly, they both significantly inhibited the expression of plasminogen activator inhibitor-type 1 (PAI-1) and type I collagenalpha1 (Col Ialpha1) genes in rat hepatic stellate cells. Thus, SB-431542 and Smad3/siRNA may be potential therapeutics for fibrosis.