Development of an Intelligent Reactive Oxygen Species-Responsive Dual-Drug Delivery Nanoplatform for Enhanced Precise Therapy of Acute Lung Injury.

Introduction: Acute lung injury (ALI) and its most severe form acute respiratory distress syndrome (ARDS) are commonly occurring devastating conditions that seriously threaten the respiratory system in critically ill patients. The current treatments improve oxygenation in patients with ALI/ARDS in the short term, but do not relieve the clinical mortality of patients with ARDS. Purpose: To develop the novel drug delivery systems that can enhance the therapeutic efficacy of ALI/ARDS and impede adverse effects of drugs. Methods: Based on the key pathophysiological process of ARDS that is the disruption of the pulmonary endothelial barrier, bilirubin (Br) and atorvastatin (As) were encapsulated into an intelligent reactive oxygen species (ROS)-responsive nanocarrier DSPE-TK-PEG (DPTP) to form nanoparticles (BA@DPTP) in which the thioketal bonds could be triggered by high ROS levels in the ALI tissues. Results: BA@DPTP could accumulate in inflammatory pulmonary sites through passive targeting strategy and intelligently release Br and As only in the inflammatory tissue via ROS-responsive bond, thereby enhancing the drugs effectiveness and markedly reducing side effects. BA@DPTP effectively inhibited NF-κB signaling and NLRP3/caspase-1/GSDMD-dependent pyroptosis in mouse pulmonary microvascular endothelial cells. BA@DPTP not only protected mice with lipopolysaccharide-induced ALI and retained the integrity of the pulmonary structure, but also reduced ALI-related mortality. Conclusion: This study combined existing drugs with nano-targeting strategies to develop a novel drug-targeting platform for the efficient treatment of ALI/ARDS.

The impact of aspirin exposure prior to intensive care unit admission on the outcomes for patients with sepsis-associated acute respiratory failure.

Objectives: This present study aimed to infer the association between aspirin exposure prior to ICU admission and the clinical outcomes of patients with Sepsis-associated acute respiratory failure (S-ARF). Methods: We obtained data from the Medical Information Mart for Intensive Care IV 2.0. Patients were divided into pre-ICU aspirin exposure group and Non-aspirin exposure group based on whether they took aspirin before ICU admission. The primary outcome is 28-day mortality. Augmented inverse propensity weighted was used to explore the average treatment effect (ATE) of the pre-ICU aspirin exposure. A generalized additive mixed model was used to analyze the longitudinal data of neutrophil to lymphocyte ratio (NLR), red cell distribution width (RDW), oxygenation index (P/F), dynamic lung compliance (Cdyn), mechanical power (MP), and mechanical power normalized to predicted body weight (WMP) in the two groups. A multiple mediation model was constructed to explore the possible mediators between pre-ICU aspirin exposure and outcomes of patients with S-ARF. Results: A total of 2090 S-ARF patients were included in this study. Pre-ICU aspirin exposure decreased 28-day mortality (ATE, -0.1945, 95% confidence interval [CI], -0.2786 to -0.1103, p < 0.001), 60-day mortality (ATE, -0.1781, 95% Cl, -0.2647 to -0.0915, p < 0.001), and hospital mortality (ATE, -0.1502, 95%CI, -0.2340 to -0.0664, p < 0.001). In subgroup analysis, the ATE for 28-day mortality, 60-day mortality, and hospital mortality were not statistically significant in the coronary care unit group, high-dose group (over 100 mg/d), and no invasive mechanical ventilation (IMV) group. After excluding these non-beneficiaries, Cdyn and P/F ratio of the pre-ICU aspirin exposure group increased by 0.31mL/cmH2O (SE, 0.21, p = 0.016), and 0.43 mmHg (SE, 0.24, p = 0.041) every hour compared to that of non-aspirin exposure group after initialing IMV. The time-weighted average of NLR, Cdyn, WMP played a mediating role of 8.6%, 24.7%, and 13% of the total effects of pre-ICU aspirin exposure and 28-day mortality, respectively. Conclusion: Pre-ICU aspirin exposure was associated with decreased 28-day mortality, 60-day mortality, and hospital mortality in S-ARF patients except those admitted to CCU, and those took a high-dose aspirin or did not receive IMV. The protective effect of aspirin may be mediated by a low dynamic level of NLR and a high dynamic level of Cdyn and WMP. The findings should be interpreted cautiously, given the sample size and potential for residual confounding.

BEZ235 reduction of cisplatin resistance on wild-type EGFR non-small cell lung cancer cells.

Cisplatin, as a first-line chemotherapy drug for advanced wild-type epidermal growth factor receptor (wtEGFR) non-small cell lung cancer (NSCLC), often loses effectiveness because of acquired drug resistance. We found that ataxia-telangiectasia mutated (ATM), ataxia-telangiectasia and Rad3-related (ATR) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) of DNA repair kinases and signal transduction molecules, protein kinase B (AKT)/target mammalian target of rapamycin (mTOR), were significantly phosphorylated in cisplatin-resistant wtEGFR NSCLC cell lines (H358R and A549R) than in their parental cells. Also, BEZ235 (dual phosphatidylinositol-3-kinase (PI3K)/mTOR inhibitor) significantly decreased the phosphorylation levels of these kinases/proteins, as detected by Western blot analysis. In H358R and A549R cells, the results of indirect immunofluorescence, single-cell gel electrophoresis, flow cytometry, methylthiazolyldiphenyl-tetrazolium bromide, clone formation assay, and scratch healing experiment showed that BEZ235 enhanced cisplatin-induced DNA damage and cell apoptosis, and effectively inhibited cellular proliferation/migration when combined with cisplatin. The data indicated that the abnormal activation of ATM/ATR/DNA-PKcs kinases and AKT/mTOR pathway might induce wtEGFR NSCLC cell resistance to cisplatin. The effects of the combination of BEZ235 and cisplatin suggested that BEZ235 should be considered as a combination therapy for patients with cisplatin-resistant wtEGFR NSCLC.

Associations between Serum Interleukins (IL-1ß, IL-2, IL-4, IL-6, IL-8, and IL-10) and Disease Severity of COVID-19: A Systematic Review and Meta-Analysis.

Background: To investigate the association between interleukins (IL-1ß, IL-2, IL-4, IL-6, IL-8, and IL-10) and the disease severity of coronavirus disease 2019 (COVID-19). Materials and Methods: We systematically searched records investigating the role of interleukins (IL-1ß, IL-2, IL-4, IL-6, IL-8, and IL-10) in COVID-19 patients in Web of Science, Pubmed, and Embase through December 2020. Data were extracted and pooled, and the weighted mean difference (WMD) and its 95% confidence interval (CI) were calculated. The funnel plot and the nonparametric trim and fill method were used to visualize and adjust the publication bias. Results: In total, 61 studies enrolled 14,136 subjects (14,041 patients and 95 healthy subjects) were enrolled in this meta-analysis. Our results showed that serum IL-2, IL-4, IL-6, and IL-10 levels were elevated in COVID-19 patients compared to healthy controls, and IL-6, IL-8, and IL-10 levels were increased in severe COVID-19 cases compared to nonsevere patients. Additionally, the levels of IL-1ß, IL-6, and IL-8 were elevated in nonsurvivor patients compared to survivors. For patients in the intensive care unit (ICU), IL-6 and IL-8 levels were increased than that in non-ICU patients. Conclusions: Elevated levels of IL-6, IL-8, and IL-10 were associated with the disease severity of COVID-19, and elevated levels of IL-1ß, IL-6, and IL-8 were related to the prognosis of COVID-19 patients, which could be used to evaluate COVID-19 patients' disease severity and prognosis.

miR-642a-5p partially mediates the effects of lipopolysaccharide on human pulmonary microvascular endothelial cells via eEF2.

Inhalation or systemic administration of lipopolysaccharide (LPS) can induce acute pulmonary inflammation and lung injury. The pulmonary vasculature is composed of pulmonary microvascular endothelial cells (PMVECs), which form a semiselective membrane for gas exchange. The miRNA miR-642a-5p has previously been reported to be up-regulated in patients with acute respiratory distress syndrome; thus, here, we examined whether this miRNA is involved in the effects of LPS on PMVECs. The levels of miR-642a-5p and mRNA encoding eukaryotic elongation factor 2 (eEF2) were detected by quantitative RT-PCR. Moesin and eEF2 protein levels were tested by western blot assay. Dual-luciferase reporter assay was used to examine the relationship between miR-642a-5p and eEF2. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and cell permeability was analyzed using the transendothelial electrical resistance assay. We report that miR-642a-5p levels are significantly up-regulated in LPS-stimulated PMVECs, and miR-642a-5p contributes to LPS-induced hyperpermeability and apoptosis of PMVECs. LPS treatment results in down-regulation of eEF2 in PMVECs. Overexpression of eEF2, a direct target of miR-642a-5p, inhibited the effect of LPS on PMVECs. miR-642a-5p promoted LPS-induced hyperpermeability and apoptosis by targeting eEF2. Thus, miR-642a-5p and eEF2 may serve as potential targets for acute lung injury/acute respiratory distress syndrome diagnosis or treatment.

Impact of Cardiovascular Disease on Clinical Characteristics and Outcomes of Coronavirus Disease 2019 (COVID-19).

BACKGROUND: To investigate the effect of cardiovascular disease (CVD) on the global pandemic, coronavirus disease 2019 (COVID-19), we analyzed the cases of laboratory-confirmed COVID-19 patients in Wuhan.Methods and Results:Data were extracted from the medical records. SARS-CoV-2 RNA was confirmed by RT-PCR. A total of 33 (53.2%) of 62 cases with CVD, who had higher prevalence of severe COVID-19 compared with non-CVD patients (P=0.027). The median age of all patients was 66.0 (53.3, 73.0) years old. Coronary artery disease (11.3%) and hypertension (38.7%) were the common coexisting CVDs in COVID-19 patients. High-sensitivity cardiac troponin I (hs-cTnI), creatinine, high-density lipoprotein-cholesterol, interleukin-6, C-reactive protein, prothrombin time, and D-dimer levels in the severe COVID-19 with CVD group were higher than in the non-severe COVID-19 with CVD group (P<0.05). For all patients, chest computed tomography (CT) showed ground-glass opacity (66.1%), local (21.0%), bilateral (77.4%), and interstitial abnormalities (4.8%). In COVID-19 patients with CVD, 27 (81.8%) were cured and discharged. 6 (18.2%) remained in hospital, including 2 (3.2%) patients requiring intubation and mechanical ventilation. The hs-cTnI levels in the remaining hospitalized patients were higher than in the discharged patients (P=0.047). CONCLUSIONS: CVDs play a vital role in the disease severity of COVID-19. COVID-19 could result in myocardial injury, which affects the prognosis of COVID-19.

MiR-802 alleviates lipopolysaccharide-induced acute lung injury by targeting Peli2.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) is a life-threatening medical condition. It is characterized by serious lung inflammation or injury. Characterizing novel miRNAs implicated in ARDS pathogenesis may provide new therapeutic strategy for managing ARDS. METHODS: We employed LPS-induced lung injury model to profile miRNAs associated with ARDS. We isolated one miRNA candidate and characterized its role in lipopolysaccharide (LPS)-induced proinflammatory cytokine production in lung macrophages. We further evaluated its functional role in ARDS model by assessing histological change, neutrophil activation, tissue permeability and tumor necrosis factor alpha (TNFα) production. We also characterized its downstream target using luciferase assay, Western blotting, enzyme-linked immunosorbent assay and cell inflammation assay. RESULTS: Microarray profiling revealed miR-802 was significantly downregulated in ARDS mouse model. LPS-induced miR-802 downregulation was confirmed in lung macrophages. Overexpression of miR-802 significantly suppressed LPS-induced inflammatory cytokine production in vitro and alleviates LPS-induced acute lung injury in vivo. Peli2 was identified as a downstream target of miR-802 and found upregulated in ARDS model. Overexpressing Peli2 abolished the antagonizing effect of miR-802 on LPS-mediated inflammatory response. CONCLUSION: MiR-802 carried a protective role against LPS-induced acute lung injury by downregulating Peli2. MiR-802/Peli2 axis may act as intervening targets to manage ARDS.

Phosphorylated ERM Mediates Lipopolysaccharide Induced Pulmonary Microvascular Endothelial Cells Permeability Through Negatively Regulating Rac1 Activity.

INTRODUCTION: The endotoxin lipopolysaccharide (LPS)-induced pulmonary endothelial barrier disruption is a key pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the molecular mechanisms underlying LPS-impaired permeability of pulmonary microvascular endothelial cells (PMVECs) are not fully understood. METHODS: Rat PMVECs were isolated and monolayered cultured, then challenged with different doses of LPS (0.1mg/L, 1mg/L, and 10mg/L). Trans-endothelial electrical resistance (TER) was utilized to measure the integrity of the endothelial barrier. Ras-related C3 botulinum toxin substrate 1 (Rac1) activity and the phosphorylation of Ezrin/Radixin/Moesin proteins (ERM) were assessed by pulldown assay and Western Blotting. Small interfering RNA (siRNA) inhibition of Rac1 and Moesin were applied to evaluate the effect of PMVEs permeability and related pathway. RESULTS: LPS induced dose and time-dependent decreases in TER and increase in ERM threonine phosphorylation, while inactivated Rac1 activity in PMVEC. siRNA study demonstrated that both Rac1 and Moesin were involved in the mediation of the LPS-induced hyperpermeability in PMVECs monolayers, and Rac1 and Moesin could regulate each other. CONCLUSION: Phosphorylated ERM mediates LPS induced PMVECs permeability through negatively regulating Rac1 activity.

Co-occurrence of bronchial papilloma and pulmonary sclerosing hemangioma in a male.

INTRODUCTION: Bronchial papilloma and pulmonary sclerosing hemangioma (PSH) are rare tumors. The development of PSH combined with bronchial papilloma in lung is extremely rare. We herein presented a case of the co-occurrence of bronchial papilloma and PSH in a male. CASE DESCRIPTION: A 48-year-old man was referred to our department for further treatment of the productive purulent cough and fever. After bronchoscopy, the biopsy of the specimen showed a bronchial papilloma in the lumen of posterior segment of the right upper lobar bronchus. For computed tomography demonstrated a focal lesion with an air bubble in the posterior segment of the right upper lobe, a lobectomy was performed and PSH was diagnosed. DISCUSSION: The report emphasizes the fact that even though some of bronchial papilloma and PSH may have a low prevalence, nonetheless, the low prevalence of both diseases in a male has meant that it has not been possible to explore the depth of association between them. CONCLUSIONS: The paper reports a case of PSH in a male suffering from bronchial papilloma which is the exceptional concurrence of these two extremely infrequent events.

Lipopolysaccharide-induced caveolin-1 phosphorylation-dependent increase in transcellular permeability precedes the increase in paracellular permeability.

BACKGROUND: Lipopolysaccharide (LPS) was shown to induce an increase in caveolin-1 (Cav-1) expression in endothelial cells; however, the mechanisms regarding this response and the consequences on caveolae-mediated transcellular transport have not been completely investigated. This study aims to investigate the role of LPS-induced Cav-1 phosphorylation in pulmonary microvascular permeability in pulmonary microvascular endothelial cells (PMVECs). METHODS: Rat PMVECs were isolated, cultured, and identified. Endocytosis experiments were employed to stain the nuclei by DAPI, and images were obtained with a fluorescence microscope. Permeability of endothelial cultures was measured to analyze the barrier function of endothelial monolayer. Western blot assay was used to examine the expression of Cav-1, pCav-1, triton-insoluble Cav-1, and triton-soluble Cav-1 protein. RESULTS: The LPS treatment induced phosphorylation of Cav-1, but did not alter the total Cav-1 level till 60 min in both rat and human PMVECs. LPS treatment also increased the triton-insoluble Cav-1 level, which peaked 15 min after LPS treatment in both rat and human PMVECs. LPS treatment increases the intercellular cell adhesion molecule-1 expression. Src inhibitors, including PP2, PP1, Saracatinib, and Quercetin, partially inhibited LPS-induced phosphorylation of Cav-1. In addition, both PP2 and caveolae disruptor MßCD inhibited LPS-induced increase of triton-insoluble Cav-1. LPS induces permeability by activating interleukin-8 and vascular endothelial growth factor and targeting other adhesion markers, such as ZO-1 and occludin. LPS treatment also significantly increased the endocytosis of albumin, which could be blocked by PP2 or MßCD. Furthermore, LPS treatment for 15 min significantly elevated Evans Blue-labeled BSA transport in advance of a decrease in transendothelial electrical resistance of PMVEC monolayer at this time point. After LPS treatment for 30 min, transendothelial electrical resistance decreased significantly. Moreover, PP2 and MßCD blocked LPS-induced increase in Evans Blue-labeled BSA level. CONCLUSION: Our study demonstrates that LPS-induced Cav-1 phosphorylation may lead to the increase of transcellular permeability prior to the increase of paracellular permeability in a Src-dependent manner. Thus, LPS-induced Cav-1 phosphorylation may be a therapeutic target for the treatment of inflammatory lung disease associated with elevated microvascular permeability.

[Effects of IL-17F/IL-17RC on the expression of caveolae-1 in rat pulmonary microvascular endothelial cells].

OBJECTIVE: To explore the expression of caveolin-1 (Cav-1) induced by interleukin-17F/IL-17 receptor C (IL-17F/IL-17RC) in rat pulmonary microvascular endothelial cells (PMVECs). METHODS: Cultured PMVECs were divided into two groups of time-dependent experiment and IL-17RC signal pathway intervention according to the results of time-dependent experimental group: namely peak time of IL-17F-induced Cav-1 and its phosphorylation (p-Cav-1) expression of PMVEC for formulating the incubation time between IL-17F and PMVEC in IL-17RC signal pathway intervention group. Time-dependent experiment group: Western blot was used to detect the expression of Cav-1 after IL-17F stimulation for 0, 0.5, 1.5, 3.0, 6.0, 12.0, 24.0 h. Cav-1 and its phosphorylation expression after IL-17F challenge for 0, 10, 30, 60, 90, 120 min were evaluated by Western blot. IL-17RC signal pathway intervention group: PMVECs were divided into two groups after a 3-day pre-treatment of siRNA. The first group received a 60-min stimulation of 100 ng/ml IL-17F before detecting the expression of p-Cav-1 while the second group was subject to a 24-hour stimulation of 100 ng/ml IL-17F before detection. In addition, control, meaningless-siRNA, IL-17RC-siRNA, IL-17F and meaningless-siRNA + IL-17F groups were set as references for two groups respectively. RESULTS: IL-17F up-regulated the expression of Cav-1 in a time-dependent manner. At 0, 0.5, 1.5, 3.0, 6.0, 12.0, 24.0 h, the relative expression levels of Cav-1 were (1.139 ± 0.134), (1.276 ± 0.166), (1.604 ± 0.080), (2.115 ± 0.231), (2.763 ± 0.226), (3.309 ± 0.493) and (3.963 ± 0.169). At 1.5 h, it was significantly higher than 0 h, peaked at 24.0 h and remained significantly higher than 0, 0.5, 1.5, 3.0, 6.0, 12.0 h (all P < 0.05). And IL-17F increased the expression of p-Cav-1 in a time-dependent manner. At 0, 10, 30, 60, 90, 120 min, the relative expression levels of p-Cav-1 were (0.540 ± 0.085), (0.880 ± 0.084), (1.437 ± 0.297), (1.491 ± 0.212), (1.017 ± 0.210) and (0.882 ± 0.074). At 10 min, p-Cav-1 was significantly higher than 0 min, peaked at 60 min, remained significantly higher than 0, 10, 30, 90, 120 min (all P < 0.05) and gradually decreased. At 120 min, it was still higher than 0 min. Compared with IL-17F group, IL-17RC-siRNA significantly inhibited IL-17F-induced Cav-1 and its phosphorylation (2.126 ± 0.318 vs 3.897 ± 0.424 and 1.014 ± 0.136 vs 1.431 ± 0.298, all P < 0.05). CONCLUSIONS: IL-17F up-regulates the expressions of Cav-1 and p-Cav-1 in a time-dependent manner in PMVECs. And the silenced expression of IL-17RC in PMVECs by IL-17RC-siRNA significantly inhibits the IL-17F-induced expressions of Cav-1 and p-Cav-1.

Expression of IL-17A and IL-17F in lipopolysaccharide-induced acute lung injury and the counteraction of anisodamine or methylprednisolone.

Th17 cytokines IL-17A and IL-17F as pro-inflammatory cytokines played an important role in triggering inflammatory responses. However, little was known about the expression of IL-17A and IL-17F in acute lung injury (ALI). Therefore, the present study investigated the expression of IL-17A and IL-17F in lipopolysaccharide (LPS)-induced ALI in rats and rat pulmonary microvascular endothelial cells (PMVEC) by enzyme-linked immunosorbant assay or reverse transcription-polymerase chains reaction. Anisodamine and methylprednisolone were also investigated as anti-inflammatory strategy in the process of LPS-induced ALI. Lung injury was evaluated by histological changes, right lung wet weight:body weight (LW/BW) ratios, and protein education and total leukocyte count of bronchoalveolar lavage fluid (BALF). Our findings showed that LPS exposure elevated the levels of leukocyte number, protein education in BALF and the ratios of LW/BW, increased the expression of IL-17A and IL-17F in the lung tissues homogenate, BALF and serum of ALI rats. Up-regulation of IL-17F expression was also observed after LPS challenge in rat PMVEC. Treatment with anisodamine or methylprednisolone significantly inhibited the increases of parameters of ALI induced by LPS, and markedly reduced the expression of IL-17A and IL-17F in rats and the IL-17F expression in PMVEC. These data suggested that IL-17A and IL-17F maybe play an important role in LPS-induced ALI via autocrine and paracrine mechanisms, and anisodamine is similar in extent to methylprednisolone that contributes to relieve LPS-induced ALI.

[Effect of tumor necrosis factor-α on expression of interleukin-17 receptor C in pulmonary microvascular endothelial cells in rats].

OBJECTIVE: To explore the effects of tumor necrosis factor-alpha (TNF-α) or methylprednisolone on the expression of interleukin-17 receptor C (IL-17RC) in rat pulmonary microvascular endothelial cells (RPMVEC). METHODS: Culture RPMVEC were randomly divided into dose-dependent and time-dependent groups. In dose-dependent group, cells were cultured with TNF-α (0, 0.1, 1, 10 µg/L TNF-α) for 3 h. In time-dependent group, cells were cultured with TNF-α (10 µg/L) for 0, 1, 3, 6, 12 h. In the drug intervention group, cells were cultured with TNF-α (10 µg/L) or methylprednisolone (200 µg/L) +TNF-α (10 µg/L) for 3 h respectively. The expression of IL-17RC in isolated and cultured RPMVEC was identified by reverse transcription-polymerase chain reaction (RT-PCR), Western blot and immunocytochemistry. The changes of IL-17RC mRNA were detected by RT-PCR after the stimulation of RPMVEC by TNF-α or methylprednisolone. RESULTS: RT-PCR and Western blot revealed that IL-17RC mRNA and protein were present in RPMVEC. The product of IL-17RC immunocytochemical reaction was predominantly located in cytoplasm and cytomembrane. In RPMVEC TNF-α significantly up-regulated IL-17RC mRNA in a dose-dependent manner (0 µg/L TNF-α group: 0.241 ± 0.010, 0.1 µg/L TNF-α group: 0.372 ± 0.017, 1 µg/L TNF-α group: 0.452 ± 0.017, 10 µg/L TNF-α group: 0.643 ± 0.042, F = 33.774, P < 0.05). In time-dependent group, the expression of IL-17RC mRNA rose at 1 h (0.417 ± 0.038), peaked at 3 h (0.674 ± 0.018), then decreased gradually at 6 h (0.378 ± 0.035), but stayed higher at 12 h (0.318 ± 0.032). When compared with 0 h group (0.197 ± 0.008), there were significant differences (F = 37.903, P < 0.05). Methylprednisolone caused a marked attenuation of TNF-α-induced IL-17RC expression (0.333 ± 0.031 vs 0.660 ± 0.026, F = 89.637, P < 0.05). CONCLUSIONS: IL-17RC is predominantly present in cytomembrane and cytoplasm of RPMVEC. TNF-α up-regulates the expression of IL-17RC mRNA. Methylprednisolone inhibits the elevated expression of IL-17RC mRNA induced by TNF-α so as to relieve the inflammatory response of PMVEC.

Caveolin-1 regulates Rac1 activation and rat pulmonary microvascular endothelial hyperpermeability induced by TNF-α.

A multiplicity of vital cellular and tissue level functions are controlled by caveolin-1 and it is considered to be an important candidate for targeted therapeutics. Rac1-cortactin signaling plays an important role in maintaining the functions of the endothelial barrier in microvascular endothelial cells. The activity of Rac1 has been shown to be regulated by caveolin-1. Therefore, the present study investigated the consequences of down-regulating caveolin-1 and the subsequent changes in activity of Rac1 and the endothelial barrier functions in primary rat pulmonary microvascular endothelial cells (RPMVECs). RPMVECs were transfected with a small hairpin RNA duplex to down-regulate caveolin-1 expression. This procedure significantly increased the activity of Rac1. Moreover, down-regulation of caveolin-1 attenuated TNF-α-induced decrease in TER, increase in the flux of FITC-BSA and the disappearance of cortactin from the cell periphery in RPMVEC. Rac1 inhibitors significantly abolished this barrier-protective effect induced by down-regulation of caveolin-1 in response to TNF-α in RPMVECs. In conclusion, our data suggest a mechanism for the regulation of Rac1 activity by caveolin-1, with consequences for activation of endothelial cells in response to TNF-α.

[Role of caveolin-1 in pulmonary microvascular endothelial cells injury induced by lipopolysaccharide in rat].

OBJECTIVE: To investigate the role of caveolin-1 (Cav-1) in the modulation of rat pulmonary microvascular endothelial cells (RPMVEC) injury induced by lipopolysaccharide (LPS). METHODS: Cultured RPMVEC were randomly divided into time-dependent injury group induced by LPS and intervention group in which cells were pretreated by protein kinase A inhibitor (PKI). In the time-dependent injury group, monolayers of cells were constructed to determine permeability changes after 10 µg/mL LPS challenge for 0, 1, 3, 6, 12 and 24 hours with the method of Evans blue-labeled albumin flux across the monolayer (Pd). Western blotting was used to determine the Cav-1 expression after LPS stimulation and the phosphorylation-Cav-1 (p-Cav-1) expression after LPS challenge for 0, 10, 30, 60, 90, 120 minutes. In the intervention group, after pre-treatment with 10 µmol/L PKI for 30 minutes, RPMVECs were challenged with 10 µg/mL LPS, and the expression of p-Cav-1 was determined 30 minutes after LPS challenge, the permeability and the Cav-1 protein expression were assessed by Pd and Western blotting, respectively. Non-stimulation group and single PKI simulation group served as controls. RESULTS: Western blotting revealed that the expression of Cav-1 protein was elevated at 1 hour (2.97 ± 0.07), peaking at 3 hours (3.77 ± 0.37), then it lowered gradually, but it was still higher at 24 hours (1.45 ± 0.18) when compared with 0 hour group (1.12±0.08) with significant differences (F=178.047, P=0.000). After RPMVEC monolayers were challenged by LPS for different periods (0, 1, 3, 6, 12 and 24 hours), there were significant increases in a time-dependent manner in Cav-1 expression in the permeability as measured by Pd [(99.67 ± 4.32)%, (118.17 ± 2.32)%, (159.00 ± 2.61)%, (141.17 ± 2.64)%, (120.17 ± 2.79)% and (108.83 ± 2.04)%, F=345.869, P=0.000] which was similar to the changes in Cav-1 expression. LPS also increased Cav-1 phosphorylation in a time-dependent manner occurring at 10 minutes (2.41 ± 0.11), peaking at 30 minutes (2.83 ± 0.10), and then it decreased gradually, finally returned to basal levels (1.03±0.04) at 120 minutes (1.04 ± 0.04) after LPS treatment with significant difference (F=519.417, P=0.000). When PKI was pre-treated with RPMVEC the expression of Cav-1 was significantly increased (5.07 ± 0.22 vs. 3.81 ± 0.23, P<0.01), and p-Cav-1 (3.93 ± 0.23 vs. 2.77±0.10, P<0.01), and RPMVEC monolayers permeability was enhanced [(184.17 ± 5.49)% vs. (151.50 ± 3.08)%, P<0.01] after being challenged. CONCLUSIONS: Up-regulated expression of Cav-1 and phosphorylation-Cav-1 that may be modulated by protein kinase A signal pathway plays an important role in RPMVEC permeability injury as induced by LPS.

[Methods for measurement of permeability coefficient of pulmonary microvascular endothelial cells in rat].

OBJECTIVE: To explore an optimal method for the measurement of pulmonary microvascular endothelial cell (PMVEC) permeability coefficient. METHODS: A monolayer of rat PMVEC model was constructed by culturing a cell suspension on transwell filter or polycarbonate filter membrane. After the state of confluence of cells was affirmed with epithelial volt-ohm meter or inverted microscope, the permeability coefficient was determined by means of transendothelial electrical resistance (TER), fluoresceinisothiocyanate-dextran (Pd), and permeation of Hanks solution (Lp) across monolayers. Meanwhile,changes in PMVEC permeability expressed by the ratio of the observed value and the original value were observed after lipopolysaccharide (LPS) challenge for 0. 5 hour or 2 hours. RESULTS: The cells reached the state of confluence as observed under inverted microscope on the third day post-seeding, and the TER and Pdat this time-point were C(39. 45 ± 3. 96) ( 2 cm2] and [(8. 52 + 0. 50) X 10-6cm/s], respectively. After PMVEC were seeded on transwell filters, the TER increased steadily in a time-dependent manner after seeding of PMVEC, reaching the summit at the fourth day post-seeding C(49. 84 ± 3. 93)f " cm2].Under the natural state, the TER, Pd and Lp of confluent PMVEC monolayers were (49.84 ±3.93) ·.* cm2, (6.15±0.63) X 106 cm/s and (6.80 + 0.62) X10< cm * s-' * cm HZO-', respectively.After PMVEC monolayers were challenged with 10 mg/L LPS for both 0. 5 hour and 2 hours, there was significant decrease in the permeability coefficient as measured by TER (0. 87+ 0. 03, 0.45 0. 04 vs. 1.00+0.08, respectively, both P< 0.05), and an increase in the permeability coefficient measured by Pd (1.33±0. 11, 2.43±0. 14 vs. 1.00+0.10, respectively, both P<0. 05) and the permeability coefficient measured by Lp (1.30± 0.07, 2.38 0.15 vs. 1.00 + 0.11, respectively, both P< 0.05) when compared with the normal group. CONCLUSION: Three methods, namely TER, Pd and Lp are available to use to assess PMVEC permeability coefficient. The combination of an inverted microscope, TER and Pd enhances the accuracy in determining PMVEC permeability coefficient, and it provides an experimental technique for studying the pathogenesis of acute lung injury in vitro.

Role of src-suppressed C kinase substrate in rat pulmonary microvascular endothelial hyperpermeability stimulated by inflammatory cytokines.

OBJECTIVE: The aim of the study was to investigate the role of src-suppressed C kinase substrate (SSeCKS) in the modulation of rat pulmonary microvascular endothelial cells (RPMVEC) permeability elicited by interleukin (IL)-1ß and tumor necrosis factor (TNF)-α. METHODS: The gene expression of SSeCKS was analyzed by reverse transcription-polymerase chain reaction. Immunoblotting was used to determine the SSeCKS protein expression and the activation of the protein kinase C (PKC) signaling pathway. A RPMVEC monolayer was constructed to determine changes of transendothelial electrical resistance (TER) and FITC-dextran flux (P (d)) across the monolayer. SSeCKS-specific small interfering RNA was transfected into RPMVEC. RESULTS: IL-1ß and TNF-α activated the PKC signaling pathway in RPMVEC, and up-regulated the gene and protein expression of SSeCKS. Depletion of endogenous SSeCKS in RPMVEC significantly attenuated cytokine-induced decrease in TER and increase in P (d), but not to the basal levels. PKC inhibitors also significantly decreased cytokine-induced hyperpermeability and SSeCKS expression. CONCLUSIONS: SSeCKS is involved in the endothelial hyperpermeability induced by IL-1ß and TNF-α in inflammatory process.

[Induction effect of platelet-activating factor on Src-suppressed C kinase substrate gene expression in rat pulmonary microvascular endothelial cells].

OBJECTIVE: To investigate the effect of platelet-activating factor (PAF) on the production of Src-suppressed C kinase substrate (SSeCKS) mRNA in rat pulmonary microvascular endothelial cell (RPMVEC) and its signal transduction pathways. METHODS: Cellular in situ hybridization was performed to reveal changes in SSeCKS mRNA expression in the cultured RPMVECs after giving PAF stimulation. RESULTS: Normal RPMVECs expressed SSeCKS mRNA at a low level, which appeared throughout the cytoplasm with specific hybridization signals. 1.5 hours of 10(-10), 10(-9), 10(-8), 10(-7) mol/L PAF incubation induced a progressive increase in SSeCKS mRNA expression. When compared to the normal control group each difference had statistical significance (0.054 9 + or - 0.000 7, 0.059 9 + or - 0.001 8, 0.069 0 + or - 0.001 8, 0.075 4 + or - 0.001 9 vs. 0.036 8 + or - 0.003 7, respectively, all P<0.05). Within 0.5, 1.5, 3, 6, 12, 24 hours of 10(-7) mol/L PAF challenge, the level of SSeCKS mRNA expression raised at 0.5 hour markedly (0.071 0 + or - 0.001 5), peaked at 1.5 hours (0.075 6 + or - 0.001 7), then began to decline gradually, and still persisted at a higher level than the normal control group until 24 hours (0.043 9 + or - 0.001 0 vs. 0.038 2 + or - 0.004 1, all P<0.05). Pre-incubation of 10 micromol/L pyrrolidine dithiocarbamate (PDTC) that inhibits activity of nuclear factor-KappaB (NF-KappaB) in RPMVECs caused a conspicuous attenuation of PAF-induced SSeCKS mRNA expression (0.049 7 + or - 0.003 2 vs. 0.071 9 + or - 0.001 9, P<0.05), whereas no change of PAF-induced effect was found by pretreatment of protein kinase C (PKC) inhibitor bis-indolylmaleimide (BIM, 0.069 7 + or - 0.002 1 vs. 0.071 9 + or - 0.001 9, P>0.05). CONCLUSION: PAF can up regulate the expression of SSeCKS mRNA in a dose- and time-dependent manner in RPMVECs. It is NF-KappaB rather than PKC signal pathway that is involved in modulation of the intracellular signaling process.

Interleukin-17F-induced pulmonary microvascular endothelial monolayer hyperpermeability via the protein kinase C pathway.

BACKGROUND: Interleukin (IL)-17F is involved in lung inflammation, but the effect of IL-17F on endothelial permeability and its signaling pathway remain ill-defined. The current study sought to investigate the effect of IL-17F on endothelium and assess the role of protein kinase C (PKC) and src-suppressed C kinase substrate (SSeCKS) in this process. METHODS: Rat pulmonary microvascular endothelial monolayers were constructed to determine changes of permeability as measured by means of FITC-dextran and Hank's solution flux across monolayers and transendothelial electrical resistance with or without IL-17F and PKC inhibitors. Additional monolayers were stained using FITC-phalloidin for filamentous actin (F-actin). The gene expression of SSeCKS was analyzed by the reverse transcription-polymerase chains. Alterations of SSeCKS protein were investigated by immunoblotting and immunoprecipitation. RESULTS: IL-17F increased endothelial monolayer permeability in a dose- and time-dependent manner. F-actin staining revealed that permeability changes were accompanied by reorganization of cytoskeleton. In the presence of PKC inhibitors, the IL-17F-induced hyperpermeability and reorganization of F-actin were attenuated. The gene and protein expression of SSeCKS were conspicuously elevated after IL-17F challenge. The process of SSeCKS phosphorylation followed a time course that mirrored the time course of hyperpermeability induced by IL-17F. IL-17F-induced SSeCKS phosphorylation was abrogated after PKC inhibitors pretreatment. The translocation of SSeCKS from the cytosol to the membrane and a significant increase in the SSeCKS association with the cytoskeleton were found after IL-17F treatment. CONCLUSIONS: IL-17F is an important mediator of increased endothelial permeability. PKC and SSeCKS are integral signaling components essential for IL-17F-induced hyperpermeability.