Overexpressed pigment epithelium-derived factor alleviates pulmonary hypertension in two rat models induced by monocrotaline and SU5416/hypoxia.

BACKGROUND: Pulmonary hypertension (PH) is a progressive and fatal cardiopulmonary disease characterized by vascular remodeling and is associated with endothelial-to-mesenchymal transition (EndoMT). The pigment epithelium-derived factor (PEDF), a secretory protein widely distributed in multiple organs, has been shown to demonstrate anti-EndoMT activity in cardiovascular diseases. In the present study, the role of PEDF in PH was investigated. METHODS: For PEDF overexpression, Sprague Dawley rats were infected with an adeno-associated virus through injection via the internal jugular vein. To establish PH models, the animals were subjected to monocrotaline or Sugen/hypoxia. Four weeks later, pulmonary artery angiography was performed, and hemodynamic parameters, right ventricular function, and vascular remodeling were evaluated. EndoMT and cell proliferation in the pulmonary arteries were assessed via immunofluorescence staining. Moreover, pulmonary artery endothelial cells (PAECs) isolated from experimental PH rats were cultured to investigate the underlying molecular mechanisms involved. RESULTS: PEDF expression was significantly downregulated in PAECs from PH patients and PH model rats. Overexpressed PEDF alleviated the development of PH by improving pulmonary artery morphology and perfusion, reducing pulmonary artery pressure, improving right ventricular function, and alleviating vascular remodeling. PEDF inhibits EndoMT and reduces excessive PAEC proliferation. Moreover, PEDF overexpression reduced EndoMT in cultured PAECs by competitively inhibiting the binding of wnt to LRP6 and downregulating phosphorylation at the 1490 site of LRP6. CONCLUSIONS: Our findings suggest that PEDF may be a potential therapeutic target for PH. We also found that PEDF can inhibit EndoMT in PAECs and may exert these effects by inhibiting the Wnt/LRP6/ß-catenin pathway.

PEDF inhibits VEGF-induced vascular leakage through binding to VEGFR2 in acute myocardial infarction.

Pigment epithelium-derived factor (PEDF) could bind to vascular endothelial growth factor receptor 2 (VEGFR2) and inhibit its activation induced by VEGF. But how PEDF affects VEGFR2 pathway is still poorly understood. In this study, we elucidated the precise mechanism underlying the interaction between PEDF and VEGFR2, and subsequently corroborated our findings using a rat AMI model. PEDF prevented endocytosis of VE-cadherin induced by hypoxia, thereby protecting the endothelium integrity. A three-dimensional model of the VEGFR2-PEDF complex was constructed by protein-protein docking method. The results showed that the VEGFR2-PEDF complex was stable during the simulation. Hydrogen bonds, binding energy and binding modes were analyzed during molecular dynamics simulations, which indicated that hydrogen bonds and hydrophobic interactions were important for the recognition of VEGFR2 with PEDF. In addition, the results from exudation of fibrinogen suggested that PEDF inhibits vascular leakage in acute myocardial infarction and confirmed the critical role of key amino acids in the regulation of endothelial cell permeability. This observation is also supported by echocardiography studies showing that the 34mer peptide sustained cardiac function during acute myocardial infarction. Besides, PEDF and 34mer could inhibit the aggregation of myofiber in the heart and promoted the formation of a dense cell layer in cardiomyocytes, which suggested that PEDF and 34mer peptide protect against AMI-induced cardiac dysfunction. These results suggest that PEDF inhibits the phosphorylation of downstream proteins, thereby preventing vascular leakage, which provides a new therapeutic direction for the treatment of acute myocardial infarction.Communicated by Ramaswamy H. Sarma.

Comparison of analgesic effects of percutaneous and transthoracic intercostal nerve block in video-assisted thoracic surgery: a propensity score-matched study.

BACKGROUND: This study aimed to compare the analgesic efficacy of transthoracic intercostal nerve block (TINB) and percutaneous intercostal nerve block (PINB) for video-assisted thoracic surgery (VATS) using a retrospective analysis. METHODS: A total of 336 patients who underwent VATS between January 2021 and June 2022 were reviewed retrospectively. Of the participants, 194 received TINB and were assigned to the T group, while 142 patients received PINB and were assigned to the P group. Both groups received 25 ml of ropivacaine via TINB or PINB at the end of the surgery. The study measured opioid consumption, pain scores, analgesic satisfaction, and safety. Propensity score matching (PSM) analysis was performed to minimize selection bias due to nonrandom assignment. RESULTS: After propensity score matching, 86 patients from each group were selected for analysis. The P group had significantly lower cumulative opioid consumption than the T group (p < 0.01). The Visual Analogue Scale (VAS) scores were lower for the P group than the T group at 6 and 12 h post-surgery (p < 0.01); however, there was no significant difference in the scores between the two groups at 3, 24, and 48 h (p > 0.05). The analgesic satisfaction in the P group was higher than in the T group (p < 0.05). The incidence of back pain, nausea or vomiting, pruritus, dizziness, and skin numbness between the two groups was statistically insignificant (p > 0.05). CONCLUSION: The study suggests that PINB provides superior analgesia for patients undergoing thoracic surgery compared to TINB without any extra adverse effects.

Adjunctive dexamethasone palmitate use for intercostal nerve block after video-assisted thoracoscopic surgery: A prospective, randomized control trial.

Objectives: The efficacy of dexamethasone palmitate in extending durations of local anesthetic blocks is uncertain. In a randomized, double-blind study of patients undergoing video-assisted thoracoscopic surgery, we tested whether intravenous or perineural dexamethasone palmitate caused prolonged analgesia after intercostal nerve block. Methods: A total of 90 patients subjected to video-assisted thoracoscopic surgery between May and December 2022 were randomly assigned to one of three intercostal nerve blocks study arms (n = 30 each), requiring the addition of 0.5% ropivacaine (23 ml) as follows: controls (C group), 2 ml saline; IV-DXP group, 2 ml saline + 2 ml (8 mg) intravenous dexamethasone palmitate; and PN-DXP group, 2 ml (8 mg) perineural dexamethasone palmitate. Time to first postoperative remedial analgesia served as primary outcome measure. Secondary endpoints included postoperative opioid consumption, pain scores by Visual Analog Scale, analgesia satisfaction, and related adverse effects. Results: Compared with controls or the IV-DXP group, time to first postoperative remedial analgesia was longer and postoperative opioid consumption for rescue analgesia was lower in the PN-DXP group (p < 0.01). Similarly, the Visual Analog Scale scores in patients at 8, 12, 18, and 24 h postoperatively were lower in the PN-DXP group than in controls and the IV-DXP group (p < 0.01). Patient satisfaction was statistically lower in the PN-DXP group, compared with either the control or IV-DXP group (p < 0.05). Clinically, the three groups did not differ significantly in occurrences of adverse effects during the 48-h postoperative monitoring period (p > 0.05). Conclusions: Perineural dexamethasone palmitate is a promising adjunct to ropivacaine intercostal nerve block by prolonging analgesia with almost no related adverse effects.

Construction of subtype classifiers and validation of a prognostic risk model based on hypoxia-associated lncRNAs for lung adenocarcinoma.

Background: Studies have shown that long non-coding RNAs (lncRNAs) are found to be hypoxia-regulated lncRNAs in cancer. Lung adenocarcinoma (LUAD) is the leading cause of cancer death worldwide, and despite early surgical removal, has a poor prognosis and a high recurrence rate. Thus, we aimed to identify subtype classifiers and construct a prognostic risk model using hypoxia-associated long noncoding RNAs (hypolncRNAs) for LUAD. Methods: Clinical data of LUAD samples with prognosis information obtained from the Gene Expression Omnibus (GEO), acted as validation dataset, and The Cancer Genome Atlas (TCGA) databases, served as training dataset, were used to screen hypolncRNAs in each dataset by univariate Cox regression analysis; the intersection set was used for subsequent analyses. Unsupervised clustering analysis was performed based on the expression of hypolncRNAs using the 'ConsensuClusterPlus' package. The tumor microenvironment (TME) was compared between LUAD subgroups by analyzing the expression of immune cell infiltration, immune components, stromal components, immune checkpoints, and chemokine secretion. To identify robust prognostically associated hypolncRNAs and construct a risk score model, multivariate Cox regression analysis was performed. Results: A total of 14 hypolncRNAs were identified. Based on the expression of these hypolncRNAs, patients with LUAD were classified into three hypolncRNA-regulated subtypes. The three subtypes differed significantly in immune cell infiltration, stromal score, specific immune checkpoints, and secretion of chemokines and their receptors. The Tumor Immune Dysfunction and Exclusion (TIDE) scores and myeloid-derived suppressor cell (MDSC) scores were also found to differ significantly among the three hypolncRNA-regulated subtypes. Four of the 14 hypolncRNAs were used to construct a signature to distinguish the overall survival (OS) in TCGA dataset (P<0.0001) and GEO dataset (P=0.0032) and sensitivity to targeted drugs in patients at different risks of LUAD. Conclusions: We characterized three regulatory subtypes of hypolncRNAs with different TMEs. We developed a signature based on hypolncRNAs, contributing to the development of personalized therapy and representing a new potential therapeutic target for LUAD.

Dual Pigment Epithelium-derived Factor and Hepatocyte Growth Factor Overexpression: A New Therapy for Pulmonary Hypertension.

Pulmonary hypertension (PH) is a disease characterized by advanced pulmonary vasculature remodeling that is thought to be curable only through lung transplantation. The application of angiogenic hepatocyte growth factor (HGF) is reported to be protective in PH through its anti-vascular remodeling effect, but excessive HGF-mediated immature neovascularization is not conducive to the restoration of pulmonary perfusion because of apparent vascular leakage. As a canonical antiangiogenic molecule, pigment epithelium-derived factor (PEDF) inhibits angiogenesis and reduces vascular permeability in a variety of diseases. However, the effect of PEDF on HGF-based PH treatment remains to be determined. In this study, monocrotaline-induced PH rats and endothelial cells isolated from rat and human PH lung tissues were used. We assessed PH progression, right cardiac function, and pulmonary perfusion in HGF- and/or PEDF-treated rats with PH. Additionally, the receptor and mechanism responsible for the role of PEDF in HGF-based PH therapy were investigated. In this study, we found that HGF and PEDF jointly prevent PH development and improve right cardiac function in rats with PH. Moreover, PEDF delivery increases the pulmonary perfusion in PH lungs and inhibits immature angiogenesis and vascular endothelial (VE)-cadherin junction disintegration induced by HGF without affecting the therapeutic inhibition of pulmonary vascular remodeling by HGF. Mechanistically, PEDF targets VE growth factor receptor 2 and suppresses its phosphorylation at Y951 and Y1175 but not Y1214. Finally, VE growth factor receptor 2/VE protein tyrosine phosphatase/VE-cadherin complex formation and Akt and Erk1/2 inactivation were observed in rat and human PH lung endothelial cells. Collectively, our data indicate that PEDF additively enhances the efficacy of HGF against PH, which may provide new insights into treatment strategies for clinical PH.

PEDF inhibits non­small cell lung cancer proliferation by suppressing autophagy through downregulation of AMPK­ULK1 signaling.

Current investigations suggest that pigment epithelial­derived factor (PEDF) can mediate the progression of non­small cell lung cancer (NSCLC) by regulating autophagy. However, the underlying mechanisms associated with autophagy remain poorly elucidated. The aim of the present study was to investigate the association between the PEDF/adenosine 5'­monophosphate­activated protein kinase (AMPK)/Unc­51 like autophagy­activated kinase 1 (ULK1) pathway and autophagy in NSCLC. Intracellular autophagy was evaluated using indicators such as the expression and activation of microtubule­associated protein light chain 3­I (LC3­I), LC3­II and p62, as well as the distribution and number of autophagosomes observed by confocal microscopy. In addition, the activity and proliferative capacity of NSCLC cells under PEDF overexpression was also examined using Cell Counting Kit­8 and lactate dehydrogenase (LDH) assays, and western blotting (WB) of related proteins. The results revealed that PEDF significantly inhibited NSCLC cell proliferation and viability, and increased LDH release and intercellular adhesion. Furthermore, PEDF suppressed the expression and activation of LC­3 and reduced the number and distribution of autophagosomes. The PEDF­induced inhibition of autophagy exhibited a direct association with the suppressed proliferation capacity and cell viability of NSCLC cells. The results of WB showed that NSCLC cells regulated autophagy through the AMPK/ULK1 signaling pathway. PEDF downregulated the AMPK/ULK1 signaling pathway, and AMPK or ULK1 overexpression markedly reduced the inhibitory effect of PEDF on autophagy. In conclusion, PEDF overexpression significantly inhibited the proliferative capacity and cell viability of NSCLC cells, as PEDF exerted an inhibitory function by regulating autophagy in NSCLC cells. Finally, it was demonstrated that autophagy may be suppressed by inhibiting the AMPK/ULK1 signaling pathway, thereby revealing a mechanism of lung cancer progression.

Pigment epithelium-derived factor attenuates myocardial fibrosis via inhibiting Endothelial-to-Mesenchymal Transition in rats with acute myocardial infarction.

Endothelial mesenchymal transition (EndMT) plays a critical role in the pathogenesis and progression of interstitial and perivascular fibrosis after acute myocardial infarction (AMI). Pigment epithelium-derived factor (PEDF) is shown to be a new therapeutic target owing to its protective role in cardiovascular disease. In this study, we tested the hypothesis that PEDF is an endogenous inhibitor of EndMT and represented a novel mechanism for its protective effects against overactive cardiac fibrosis after AMI. Masson's trichrome (MTC) staining and picrosirius red staining revealed decreased interstitial and perivascular fibrosis in rats overexpressing PEDF. The protective effect of PEDF against EndMT was confirmed by co-labeling of cells with the myofibroblast and endothelial cell markers. In the endothelial cells of microvessels in the ischemic myocardium, the inhibitory effect of PEDF against nuclear translocation of ß-catenin was observed through confocal microscopic imaging. The correlation between antifibrotic effect of PEDF and inactivation of ß-catenin was confirmed by co-transfecting cells with lentivirus carrying PEDF or PEDF RNAi and plasmids harboring ß-catenin siRNA(r) or constitutive activation of mutant ß-catenin. Taken together, these results establish a novel finding that PEDF could inhibit EndMT related cardiac fibrosis after AMI by a mechanism dependent on disruption of ß-catenin activation and translocation.