Inhibition of VEGF blocks TGF-beta1 production through a PI3K/Akt signalling pathway

PI3Kδ Mediates Fibrosis by Patient-Derived Vitreous

The epithelial-mesenchymal transition (EMT) is a fundamental process in developing fibrotic diseases, including forming epiretinal membranes (ERMs). ERMs can result in irreversible vision loss. Previous research has demonstrated that vitreous (VIT) derived from patients with proliferative diabetic retinopathy can stimulate angiogenesis through the Axl/PI3K/Akt pathway. Building upon this knowledge, we aimed to explore the influence of VIT from patients with macular membranes in ARPE-19 cells. Our findings reveal that patient-derived VIT from individuals with macular membranes promotes EMT and phosphoinositide 3-kinase-delta (PI3Kδ) expression in ARPE-19 cells. To elucidate the function of PI3Kδ in the ERM, we conducted experiments involving the knockout of p110δ, a key subunit of PI3Kδ, and observed that its absence hinders EMT induced by patient-derived VIT. Moreover, p110δ depletion reduces cell proliferation and migration in ARPE-19 cells. Remarkably, these effects were further corroborated by applying the p110δ inhibitor idelalisib, which blocks fibrosis in the laser-induced fibrosis model. Collectively, our results propose that p110δ plays a critical role in the progression of ERMs. Consequently, targeting p110δ emerges as a promising therapeutic approach for mitigating fibrosis. These findings contribute to a better understanding of the underlying mechanisms involved in ERM formation and highlight the potential for p110δ-directed antifibrotic therapy in retinal diseases.

Canagliflozin combined with aerobic exercise protects against chronic heart failure in rats

To determine the efficacy and potential protective mechanism of canagliflozin combined with aerobic exercise in treating chronic heart failure (CHF). Isoproterenol was injected into rats to create CHF models. The rats were then subsequently divided into saline, canagliflozin (3 mg/kg/d), aerobic exercise training, and canagliflozin combined with aerobic exercise training. Compared to the CHF group, the canagliflozin combined with the aerobic exercise group had superior ventricular remodeling and cardiac function. In rats treated with canagliflozin combined with aerobic exercise, the expression of cytochrome P450 (CYP) 4A3, CYP4A8, COL1A1, COL3A1, and FN1 was reduced, while the expression of CYP26B1, ALDH1A2, and CYP1A1 increased significantly. Additionally, canagliflozin combined with aerobic exercise decreased the phosphorylation of AKT and ERK1/2. Canagliflozin combined with aerobic exercise has a positive effect on the development of CHF via the regulation of retinol metabolism and the AKT/ERK signaling pathway.

Vocal fold fibroblasts and exposure to vibration in vitro: Does sex matter?

Studies have shown that certain vocal fold pathologies are more common in one sex than the other. This is often explained by differences in the composition of the lamina propria and anatomical differences between female and male vocal folds, resulting in e.g. different fundamental frequencies. Here, we investigated a potential sex-specific voice frequency effect in an in vitro setting using vocal fold fibroblasts from one male and one female donor with and without cigarette smoke extract (CSE) addition. After exposure to either male or female vibration frequency with or without CSE, cells and supernatants were harvested. Gene and protein analysis were performed by means of qPCR, western blot, ELISA and Luminex. We found that exposure of cells to both male and female vibration pattern did not elicit significant changes in the expression of extracellular matrix-, inflammation-, and fibrosis-related genes, compared to control cells. The addition of CSE to vibration downregulated the gene expression of COL1A1 in cells exposed to the female vibration pattern, as well as induced MMP1 and PTGS2 in cells exposed to both female and male vibration pattern. The protein expression of MMP1 and COX2 was found to be significantly upregulated only in cells exposed to CSE and female vibration pattern. To conclude, different vibration patterns alone did not cause different responses of the cells. However, the female vibration pattern in combination with CSE had a tendency to elicit/maintain more pro-inflammatory responses in cells than the male vibration pattern.

Research progress on the mechanism of astragaloside IV in the treatment of asthma

Asthma is a common chronic respiratory disease, and its treatment is a core problem and challenge in clinical practice. Glucocorticoids (GCs) are the first-line therapy for the treatment of asthma. Local and systemic adverse reactions caused by GCs create obstacles to the treatment of asthma. Therefore, the research target is to find a new, safe, and effective therapeutic medicine at present. Natural products are an important source for treating asthma with low cost and low toxicity. Astragaloside IV (AS-IV) is an active ingredient of traditional Chinese medicine Astragalus mongholicus Bunge. Previous studies have indicated that AS-IV plays a therapeutic role in the treatment of asthma by inhibiting airway inflammation and remodeling the airway, and by regulating immunity and neuroendocrine function (Fig. 1) . It has a variety of biological characteristics such as multi-target intervention, high safety, and good curative effect. This article reviews the specific mechanism of AS-IV for the treatment of asthma to provide references for subsequent research.

Targeted VEGFA therapy in regulating early acute kidney injury and late fibrosis

Damage to peritubular capillaries is a key process that contributes to acute kidney injury (AKI) progression. Vascular endothelial growth factor A (VEGFA) plays a critical role in maintaining the renal microvasculature. However, the physiological role of VEGFA in various AKI durations remains unclear. A severe unilateral ischemia‒reperfusion injury model was established to provide an overview of VEGFA expression and the peritubular microvascular density from acute to chronic injury in mouse kidneys. Therapeutic strategies involving early VEGFA supplementation protecting against acute injury and late anti-VEGFA treatment for fibrosis alleviation were analyzed. A proteomic analysis was conducted to determine the potential mechanism of renal fibrosis alleviation by anti-VEGFA. The results showed that two peaks of extraglomerular VEGFA expression were observed during AKI progression: one occurred at the early phase of AKI, and the other occurred during the transition to chronic kidney disease (CKD). Capillary rarefaction progressed despite the high expression of VEGFA at the CKD stage, and VEGFA was associated with interstitial fibrosis. Early VEGFA supplementation protected against renal injury by preserving microvessel structures and counteracting secondary tubular hypoxic insults, whereas late anti-VEGFA treatment attenuated renal fibrosis progression. The proteomic analysis highlighted an array of biological processes related to fibrosis alleviation by anti-VEGFA, which included regulation of supramolecular fiber organization, cell-matrix adhesion, fibroblast migration, and vasculogenesis. These findings establish the landscape of VEGFA expression and its dual roles during AKI progression, which provides the possibility for the orderly regulation of VEGFA to alleviate early acute injury and late fibrosis.

Is there a role for specialized pro-resolving mediators in pulmonary fibrosis?

Pulmonary fibrotic diseases are characterized by proliferation of lung fibroblasts and myofibroblasts and excessive deposition of extracellular matrix proteins. Depending on the specific form of lung fibrosis, there can be progressive scarring of the lung, leading in some cases to respiratory failure and/or death. Recent and ongoing research has demonstrated that resolution of inflammation is an active process regulated by families of small bioactive lipid mediators termed "specialized pro-resolving mediators." While there are many reports of beneficial effects of SPMs in animal and cell culture models of acute and chronic inflammatory and immune diseases, there have been fewer reports investigating SPMs and fibrosis, especially pulmonary fibrosis. Here, we will review evidence that resolution pathways are impaired in interstitial lung disease, and that SPMs and other similar bioactive lipid mediators can inhibit fibroblast proliferation, myofibroblast differentiation, and accumulation of excess extracellular matrix in cell culture and animal models of pulmonary fibrosis, and we will consider future therapeutic implications of SPMs in fibrosis.

Evolving Strategies in the Treatment of Anaemia in Chronic Kidney Disease: The HIF-Prolyl Hydroxylase Inhibitors

Chronic kidney disease (CKD) affects approximately 10% of the worldwide population; anaemia is a frequent complication. Inadequate erythropoietin production and absolute or functional iron deficiency are the major causes. Accordingly, the current treatment is based on iron and erythropoiesis stimulating agents (ESAs). Available therapy has dramatically improved the management of anaemia and the quality of life. However, safety concerns were raised over ESA use, especially when aiming to reach near-to-normal haemoglobin levels with high doses. Moreover, many patients show hypo-responsiveness to ESA. Hypoxia-inducible factor (HIF) prolyl hydroxylase domain (PHD) inhibitors (HIF-PHIs) were developed for the oral treatment of anaemia in CKD to overcome these concerns. They simulate the body's exposure to moderate hypoxia, stimulating the production of endogenous erythropoietin. Some molecules are already approved for clinical use in some countries. Data from clinical trials showed non-inferiority in anaemia correction compared to ESA or superiority for placebo. Hypoxia-inducible factor-prolyl hydroxylase domain inhibitors may also have additional advantages in inflamed patients, improving iron utilisation and mobilisation and decreasing LDL-cholesterol. Overall, non-inferiority was also shown in major cardiovascular events, except for one molecule in the non-dialysis population. This was an unexpected finding, considering the lower erythropoietin levels reached using these drugs due to their peculiar mechanism of action. More data and longer follow-ups are necessary to better clarifying safety issues and further investigate the variety of pathways activated by HIF, which could have either positive or negative effects and could differentiate HIF-PHIs from ESAs.

TGF-β from the Porcine Intestinal Cell Line IPEC-J2 Induced by Porcine Circovirus 2 Increases the Frequency of Treg Cells via the Activation of ERK (in CD4+ T Cells) and NF-κB (in IPEC-J2)

Porcine circovirus 2 (PCV2) causes immunosuppression. Piglets infected with PCV2 can develop enteritis. Given that the gut is the largest immune organ, however, the response of the gut's immune system to PCV2 is still unclear. Here, IPEC-J2 cells with different treatments were co-cultured with PBMC or CD4⁺ T cells (Transwell). Flow cytometry and Western blotting revealed that PCV2-infected IPEC-J2 increased the frequency of CD4⁺ T cells among piglets' peripheral blood mononuclear cells (PBMCs) and caused CD4⁺ T cells to undergo a transformation into Foxp3⁺ regulatory T cells (Treg cells) via activating CD4⁺ T ERK. Cytokines production and an inhibitor assay showed that the induction of Tregs by PCV2-infected IPEC-J2 was dependent on TGF-β induced by PCV2 in IPEC-J2, which was associated with the activation of NF-κB. Taken together, PCV2-infected IPEC-J2 activated NF-κB to stimulate the synthesis of TGF-β, which enhanced the differentiation of CD4⁺ T cells into Treg cells through the activation of ERK in CD4⁺ T cells. This information sheds light on PCV2's function in the intestinal immune system and suggests a potential immunosuppressive mechanism for PCV2 infection.

Pro- and anti-fibrotic effects of vascular endothelial growth factor in chronic kidney diseases

Renal fibrosis is the inevitable common end-point of all progressive chronic kidney diseases. The underlying mechanisms of renal fibrosis are complex, and currently there is no effective therapy against renal fibrosis. Renal microvascular rarefaction contributes to the progression of renal fibrosis; however, an imbalance between proangiogenic and antiangiogenic factors leads to the loss of renal microvasculature. Vascular endothelial growth factor (VEGF) is the most important pro-angiogenic factor. Recent studies have unraveled the involvement of VEGF in the regulation of renal microvascular rarefaction and fibrosis via various mechanisms; however, it is not clear whether it has anti-fibrotic or pro-fibrotic effect. This paper reviews the available evidence pertaining to the function of VEGF in the fibrotic process and explores the associated underlying mechanisms. Our synthesis will help identify the future research priorities for developing specialized treatments for alleviating or preventing renal fibrosis. Abbreviation: VEGF: vascular endothelial growth factor; CKD: chronic kidney disease; ESKD: end-stage kidney disease; ER: endoplasmic reticulum; VEGFR: vascular endothelial growth factor receptor; AKI: acute kidney injury; EMT: epithelial-to-mesenchymal transition; HIF: hypoxia-inducible factor; α-SMA: α smooth muscle actin; UUO: unilateral ureteral obstruction; TGF-β: transforming growth factor-β; PMT: pericyte-myofibroblast transition; NO: nitric oxide; NOS: nitric oxide synthase; nNOS: neuronal nitric oxide synthase; iNOS: inducible nitric oxide synthase; eNOS: endothelial nitric oxide synthase; sGC: soluble guanylate cyclase; PKG: soluble guanylate cyclase dependent protein kinases; UP R: unfolded protein response

Dioscin exhibits protective effects on in vivo and in vitro asthma models via suppressing TGF-β1/Smad2/3 and AKT pathways

Dioscin is a natural product that possesses protective effects on multiple chronic injuries, but its effects on asthma are not fully understood. Herein, we evaluated its effects on asthmatic mice established by ovalbumin (OVA) sensitization and challenges and further explored the mechanism. Inflammatory cells in bronchoalveolar lavage fluids (BALFs) were analyzed using Diff-Quik staining. OVA-specific immunoglobulin E (IgE)/IgG1 in serum and inflammatory cytokines (interleukin 4[IL-4], IL-5, IL-13, and tumor necrosis factor-α) in BALFs and lung tissues were measured using Enzyme-Linked Immunosorbent Assay Kits. Hematoxylin and eosin, periodic acid-Schiff, and immunohistochemistry staining showed histopathological changes in lung tissues. Epithelial-mesenchymal transition (EMT) in human bronchial epithelial (16HBE) cells was assessed by immunofluorescence staining. Hydroxyproline content was used to evaluate collagen deposition. Polymerase chain reaction and Western blot were performed to measure messenger RNA and protein expression. We found that dioscin treatment (particularly at the dose of 80 mg/kg) significantly inhibited pulmonary inflammation in asthmatic mice, as evidenced by the decreased serum OVA-specific IgE/IgG1 and the reduced inflammatory cells and cytokines in BALFs and lung tissues. Moreover, dioscin effectively ameliorated the goblet cell hyperplasia, mucus hypersecretion, collagen deposition, and smooth muscle hyperplasia in the airways of asthmatic mice. Mechanistically, dioscin restrained the activated TGF-β1/Smad2/3 and protein kinase B (AKT) signal pathways in lung tissues and potently reversed the TGF-β1-induced EMT and phosphorylation of Smad2/3 and AKT in 16HBE cells. Collectively, dioscin displayed protective effects on OVA-induced asthmatic mice via adjusting TGF-β1/Smad2/3 and AKT signal pathways, supporting the fact that dioscin could be a candidate for chronic asthma prevention in the future.

Schisandrin B Attenuates Airway Inflammation and Airway Remodeling in Asthma by Inhibiting NLRP3 Inflammasome Activation and Reducing Pyroptosis

Asthma is a chronic inflammatory disorder of the airways. Schisandrin B (SB) is the main effective component. This study investigated the effects of SB on airway inflammation and airway remodeling in asthma. The rat model of asthma was established. The rats were treated with SB to evaluate the effects of SB on airway inflammation, airway remodeling, NLRP3 inflammasome activation, and pyroptosis. Alveolar macrophages of rats were isolated, and the macrophage inflammatory model was established by lipopolysaccharide (LPS) induction. The LPS-induced macrophages were treated with SB. The binding relationship between miR-135a-5p and TPRC1 was analyzed. LPS + SB-treated macrophages were transfected with miR-135a-5p inhibitor. The expressions of key factors of the STAT3/NF-κB pathway were detected. SB reduced airway inflammation and airway remodeling in asthmatic rats. SB inhibited NLRP3 inflammasome activation and reduced pyroptosis in asthmatic rats and LPS-induced macrophages. SB reversely regulated the miR-135a-5p/TRPC1 axis. Downregulation of miR-135a-5p attenuated the inhibitory effect of SB on NLRP3 inflammasome activation. SB inhibited the STAT3/NF-κB pathway via the miR-135a-5p/TRPC1 axis. In conclusion, SB inhibited NLRP3 inflammasome activation and reduced pyroptosis via the miR-135a-5p/TRPC1/STAT3/NF-κB axis, thus alleviating airway inflammation and airway remodeling in asthma. This study may confer novel insights for the management of asthma.

The Importance of Being PI3K in the RAS Signaling Network

Ras proteins are essential mediators of a multitude of cellular processes, and its deregulation is frequently associated with cancer appearance, progression, and metastasis. Ras-driven cancers are usually aggressive and difficult to treat. Although the recent Food and Drug Administration (FDA) approval of the first Ras G12C inhibitor is an important milestone, only a small percentage of patients will benefit from it. A better understanding of the context in which Ras operates in different tumor types and the outcomes mediated by each effector pathway may help to identify additional strategies and targets to treat Ras-driven tumors. Evidence emerging in recent years suggests that both oncogenic Ras signaling in tumor cells and non-oncogenic Ras signaling in stromal cells play an essential role in cancer. PI3K is one of the main Ras effectors, regulating important cellular processes such as cell viability or resistance to therapy or angiogenesis upon oncogenic Ras activation. In this review, we will summarize recent advances in the understanding of Ras-dependent activation of PI3K both in physiological conditions and cancer, with a focus on how this signaling pathway contributes to the formation of a tumor stroma that promotes tumor cell proliferation, migration, and spread.

miR-15a-5p suppresses peritoneal fibrosis induced by peritoneal dialysis via targeting VEGF in rats

Aim

When peritoneal fibrosis (PF) causes ultrafiltration failure in peritoneal dialysis (PD) patients, PD has to be discontinued. Currently, there is no effective way to relieve PF. In this study, we aimed to determine whether miR-15a-5p is involved in PF and to determine the underlying mechanism.

Methods

Six normal rats were used as the control group. A uremic rat model was constructed using 5/6 nephrectomy in a Sprague–Dawley model. The uremic rats were randomly divided into PD, lentivirus-transfected, negative control, VEGFR-inhibited and gavage control groups. Except for the control group, all uremia rats received continuous PD for 28 days. In the lentivirus-transfected group, the miR-15a-5p plasmid was injected into the peritoneal cavity to upregulate miR-15a-5p expression. Axitinib was used to block vascular endothelial growth factor receptor (VEGFR) in the peritoneum. The mRNA levels of miR-15a-5p and VEGF were detected by qRT-PCR and FISH. Protein levels of VEGF, E-cadherin, collagen IV, fibronectin and α-SMA were detected by western blot and immunohistochemistry.

Results

PD leads to peritoneal thickening and fibrosis. The expression level of miR-15a-5p decreased and that of VEGF increased in the PD group than in the controls. Additionally, E-cadherin was significantly reduced while collagen IV, fibronectin and α-SMA were obviously increased in the PD group compared to controls. FISH showed that VEGF might be the target gene of miR-15a-5p. Overexpression of miR-15a-5p or inhibition of VEGFR could reverse PF.

Conclusion

miR-15a-5p may participate in the endothelial to mesenchymal transition of PF caused by PD through VEGF.

Amelioration of testosterone-induced benign prostatic hyperplasia using febuxostat in rats: The role of VEGF/TGFβ and iNOS/COX-2

Benign prostatic hyperplasia (BPH) is a common male disorder. Febuxostat is a non-purine, selective inhibitor of xanthine oxidase (XO), which has a strong antioxidant capacity and pleiotropic pharmacological properties. This study's objective was to explore the potential ameliorative effects of febuxostat against testosterone-induced BPH in rats. Febuxostat (10 mg/kg/day, per os [p.o.]) prevented increased prostate index levels, serum levels of prostate-specific antigen (PSA), and testosterone levels compared to animals treated with testosterone alone, when administered for 28 days. Histological examination indicated that febuxostat dramatically ameliorated pathological changes in the prostate architecture compared to the testosterone group. Similarly, febuxostat markedly improved testosterone-induced oxidative stress by inhibiting the increase in lipid peroxide and nitrite content, and by reducing the level of depletion of reduced glutathione (GSH) and superoxide dismutase (SOD) activity, which significantly reduced the prostate content of pro-inflammatory cytokines, including tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6). Furthermore, febuxostat significantly reduced the prostatic content, both in terms of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) messenger ribonucleic acid (mRNA) levels, and of protein levels. Moreover, compared to the testosterone group, febuxostat's beneficial effects prevented the increase in growth factors, comprising vascular endothelial cell growth factor A (VEGF-A) and transforming growth factor beta (TGF-β) protein levels. Its ameliorating effects were equal to those of finasteride, which is the most widely used remedy for BPH. In conclusion, this study provides novel evidence that febuxostat experimentally attenuates testosterone-induced BPH in rats, at least in part by inhibiting iNOS/COX-2 and VEGF/TGF-β pathways.

MiR-503 suppresses fibroblast activation and myofibroblast differentiation by targeting VEGFA and FGFR1 in silica-induced pulmonary fibrosis

Inhalation and deposition of crystalline silica particles in the lung can cause pulmonary fibrosis, then leading to silicosis. Given the paucity of effective drugs for silicosis, new insights for understanding the mechanisms of silicosis, including lung fibroblast activation and myofibroblast differentiation, are essential to explore therapeutic strategies. Our previous research showed that the up-regulation of miR-503 alleviated silica-induced pulmonary fibrosis in mice. In this study, we investigated whether miR-503 can regulate the TGF-β1-induced effects in lung fibroblasts. Mimic-based strategies aiming at up-regulating miR-503 were used to discuss the function of miR-503 in vivo and in vitro. We found that the expression level of miR-503 was decreased in fibroblasts stimulated by TGF-β1, and the up-regulation of miR-503 reduced the release of fibrotic factors and inhibited the migration and invasion abilities of fibroblasts. Combined with the up-regulation of miR-503 in a mouse model of silica-induced pulmonary fibrosis, we revealed that miR-503 mitigated the TGF-β1-induced effects in fibroblasts by regulating VEGFA and FGFR1 and then affecting the MAPK/ERK signalling pathway. In conclusion, miR-503 exerted protective roles in silica-induced pulmonary fibrosis and may represent a novel and potent candidate for therapeutic strategies in silicosis.

Hydrophobic ion pair loaded self-emulsifying drug delivery system (SEDDS): A novel oral drug delivery approach of cromolyn sodium for management of bronchial asthma

The aim of the present study is to develop a self-emulsifying drug delivery system (SEDDS) for the hydrophobic ion pair (HIP) complex of cromolyn sodium (CS), in order to enhance its intestinal absorption and biological activity. Two ion pairing agents (IPAs) were investigated: hexadecyl pyridininum chloride (HPC) and myristyl trimethyl ammonium bromide (MTAB). The optimum binding efficiency for complexation between investigated IPAs and CS was observed at a molar ratio of 1.5:1, where CS binding efficiency was found to be 76.10 ± 2.12 and 91.37 ± 1.73% for MTAB and HPC, respectively. The two prepared complexes exhibited a significant increase in partition coefficient indicating increased lipophilicity. The optimized CS-HIP complex was incorporated into SEDDS formulations. SEDDS formulations F2 (40% oleic acid, 40% Brij^TM98, 20% propylene glycol) and F3 (25% oleic acid, 50% Brij^TM98, 25% propylene glycol) exhibited nanometric droplet diameters with monodisperse distribution and nearly neutral zeta potential values. Ex vivo intestinal permeation study, using the non-everted gut sac technique, revealed a significantly higher cumulative amount of permeated drug, after 2 h, for F2 and F3 (53.836 and 77.617 µg/cm², respectively) compared to 8.649 µg/cm² for plain CS solution. The in vivo evaluation of plain CS solution compared to F2 and F3 was conducted in an ovalbumin sensitization-induced bronchial asthma rat model. Lung function parameters (tidal volume and peak expiratory flow), biochemical parameters (interleukin-5, immunoglobulin-E, myeloperoxidase and airway remodelling parameters) were assessed in addition to histopathological examination. The results indicated the superiority of F3 followed by F2 compared to plain CS solution for prophylaxis of bronchial asthma in rats.

Soufeng Yuchuan decoction mitigates the ovalbumin-induced lung damage in a rat model of asthma

Airway remodeling is a key feature of asthma. Extracellular matrix synthesis and vascular remodeling respectively regulated by transforming growth factor (TGF-β1) and vascular endothelial growth factor (VEGF), are important for the airway remodeling. This study aimed to investigate the effect of Soufeng Yuchuan (SFYC) decoction, a Traditional Chinese Medicine, on airway remodeling and expression of VEGF and TGF-β1 in asthma model rats. A rat model of asthma was induced by ovalbumin (OVA) treatment. The results showed that SFYC decoction improved general conditions and reduced the damage in lung tissues in asthma model rats. Furthermore, SFYC decoction significantly reduced the OVA-induced levels of VEGF and TGF-β1 in sera and in bronchoalveolar lavage fluid. Moreover, SFYC decoction decreased the OVA-induced VEGF mRNA and protein levels in lung tissues in asthma model rats. Interestingly, SFYC with high dose was more potent in reducing TGF-β1 level in rat sera and BALF than dexamethasone (positive control). In summary, SFYC decoction effectively mitigates lung damage in OVA-induced asthma model rats, which was associated with inhibition of VEGF and TGF-β1.

Anti-inflammatory effects of linalool on ovalbumin-induced pulmonary inflammation

Linalool is a natural product present in fruits and aromatic plants with biological activities. Researchers have reported that the inhalation of linalool exerts anti-inflammatory activities. In this study, we examined the therapeutic effects of linalool on airway inflammation and mucus overproduction in mice with allergic asthma. Oral administration of linalool significantly inhibited the levels of eosinophil numbers, Th2 cytokines and immunoglobulin E (IgE) caused by ovalbumin (OVA) exposure. Linalool exerted preventive effects against the influx of inflammatory cells and mucus hypersecretion in the lung tissues. Linalool also dose-dependently decreased the levels of inducible nitric oxide synthase (iNOS) expression and protein kinase B (AKT) activation in the lung tissues. Linalool effectively downregulated the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) caused by OVA exposure. Furthermore, linalool exerted inhibitory effect on OVA-induced airway hyperresponsiveness (AHR). In the in vitro study, the increased secretion of MCP-1 was attenuated with linalool treatment in lipopolysaccharide (LPS)-stimulated H292 airway epithelial cells. In conclusion, linalool effectively exerts a protective role in OVA-induced airway inflammation and mucus hypersecretion, and its protective effects are closely related to the downregulation of inflammatory mediators and MAPKs/NF-κB signaling.

Insulin-Like Growth Factor-1 Signaling in Lung Development and Inflammatory Lung Diseases

Insulin-like growth factor-1 (IGF-1) was firstly identified as a hormone that mediates the biological effects of growth hormone. Accumulating data have indicated the role of IGF-1 signaling pathway in lung development and diseases such as congenital disorders, cancers, inflammation, and fibrosis. IGF-1 signaling modulates the development and differentiation of many types of lung cells, including airway basal cells, club cells, alveolar epithelial cells, and fibroblasts. IGF-1 signaling deficiency results in alveolar hyperplasia in humans and disrupted lung architecture in animal models. The components of IGF-1 signaling pathways are potentiated as biomarkers as they are dysregulated locally or systemically in lung diseases, whereas data may be inconsistent or even paradoxical among different studies. The usage of IGF-1-based therapeutic agents urges for more researches in developmental disorders and inflammatory lung diseases, as the majority of current data are collected from limited number of animal experiments and are generally less exuberant than those in lung cancer. Elucidation of these questions by further bench-to-bedside researches may provide us with rational clinical diagnostic approaches and agents concerning IGF-1 signaling in lung diseases.

Phosphorylation of low density lipoprotein receptor-related protein 6 is involved in receptor for advanced glycation end product-mediated β-catenin stabilization in a toluene diisocyanate-induced asthma model

BACKGROUND

We have previously demonstrated that the receptor for advanced glycation end products (RAGE)/β-catenin axis plays a vital role in regulating airway inflammation and airway remodeling in a toluene diisocyanate (TDI)-induced murine asthma model. However, the exact mechanism of β-catenin activation remains unclear. Given that phosphorylation of the low-density lipoprotein receptor-related protein 6 (Lrp6) is a key step in mediating β-catenin stabilization in canonical wnt/β-catenin signaling, we explored the possible relationship between RAGE and Lrp6 in regulating β-catenin stabilization in TDI-induced asthma.

METHODS

In this study, a TDI-induced murine asthma model was generated, and mice were treated with a specific inhibitor of RAGE. In vitro, the human bronchial epithelial cell line 16HBE was treated with TDI-human serum albumin (TDI-HSA). RAGE overexpression or knockdown cells were also constructed and assessed.

RESULTS

The results showed that RAGE inhibition or RAGE knockdown decreased β-catenin nuclear accumulation and the expression of relevant β-catenin targeted genes (VEGF, MMP9, TGF-β1) in the TDI-induced murine asthma model and TDI-HSA-treated 16HBE cells, respectively. Silencing of RAGE reversed the TDI-induced increase in phospho-ERK1/2 (p-ERK) and phospho-Lrp6 (p-Lrp6) in 16HBE cells. Pretreatment with the extracellular signal-regulated kinase (ERK)1/2 inhibitor U0126 suppressed TDI-induced Lrp6 phosphorylation. Furthermore, knockdown of Lrp6 in 16HBE cells decreased β-catenin nuclear translocation and the expression of VEGF, MMP9, and TGF-β1.

CONCLUSION

These data suggested that the RAGE/ERK axis modulates Lrp6 phosphorylation, contributing to β-catenin stabilization in a TDI-induced murine model.

Deletion of Endothelial Transforming Growth Factor-β Signaling Leads to Choroidal Neovascularization

The molecular pathogenesis of choroidal neovascularization (CNV), an angiogenic process that critically contributes to vision loss in age-related macular degeneration, is unclear. Herein, we analyzed the role of transforming growth factor (TGF)-β signaling for CNV formation by generating a series of mutant mouse models with induced conditional deletion of TGF-β signaling in the entire eye, the retinal pigment epithelium (RPE), or the vascular endothelium. Deletion of TGF-β signaling in the eye caused CNV, irrespectively if it was ablated in newborn or 3-week-old mice. Areas of CNV showed photoreceptor degeneration, multilayered RPE, basal lamina deposits, and accumulations of monocytes/macrophages. The changes progressed, leading to marked structural and functional alterations of the retina. Although the specific deletion of TGF-β signaling in the RPE caused no obvious changes, specific deletion in vascular endothelial cells caused CNV and a phenotype similar to that observed after the deletion in the entire eye. We conclude that impairment of TGF-β signaling in the vascular endothelium of the eye is sufficient to trigger CNV formation. Our findings highlight the importance of TGF-β signaling as a key player in the development of ocular neovascularization and indicate a fundamental role of TGF-β signaling in the pathogenesis of age-related macular degeneration.

Microbes Are Associated with Host Innate Immune Response in Idiopathic Pulmonary Fibrosis

RATIONALE

Differences in the lung microbial community influence idiopathic pulmonary fibrosis (IPF) progression. Whether the lung microbiome influences IPF host defense remains unknown.

OBJECTIVES

To explore the host immune response and microbial interaction in IPF as they relate to progression-free survival (PFS), fibroblast function, and leukocyte phenotypes.

METHODS

Paired microarray gene expression data derived from peripheral blood mononuclear cells as well as 16S ribosomal RNA sequencing data from bronchoalveolar lavage obtained as part of the COMET-IPF (Correlating Outcomes with Biochemical Markers to Estimate Time-Progression in Idiopathic Pulmonary Fibrosis) study were used to conduct association pathway analyses. The responsiveness of paired lung fibroblasts to Toll-like receptor 9 (TLR9) stimulation by CpG-oligodeoxynucleotide (CpG-ODN) was integrated into microbiome-gene expression association analyses for a subset of individuals. The relationship between associated pathways and circulating leukocyte phenotypes was explored by flow cytometry.

MEASUREMENTS AND MAIN RESULTS

Down-regulation of immune response pathways, including nucleotide-binding oligomerization domain (NOD)-, Toll-, and RIG1-like receptor pathways, was associated with worse PFS. Ten of the 11 PFS-associated pathways correlated with microbial diversity and individual genus, with species accumulation curve richness as a hub. Higher species accumulation curve richness was significantly associated with inhibition of NODs and TLRs, whereas increased abundance of Streptococcus correlated with increased NOD-like receptor signaling. In a network analysis, expression of up-regulated signaling pathways was strongly associated with decreased abundance of operational taxonomic unit 1341 (OTU1341; Prevotella) among individuals with fibroblasts responsive to CpG-ODN stimulation. The expression of TLR signaling pathways was also linked to CpG-ODN responsive fibroblasts, OTU1341 (Prevotella), and Shannon index of microbial diversity in a network analysis. Lymphocytes expressing C-X-C chemokine receptor 3 CD8 significantly correlated with OTU1348 (Staphylococcus).

CONCLUSIONS

These findings suggest that host-microbiome interactions influence PFS and fibroblast responsiveness.

Phosphoinositide 3-Kinase in Asthma: Novel Roles and Therapeutic Approaches

Asthma manifests as airway hyperresponsiveness and inflammation, including coughing, wheezing, and shortness of breath. Immune cells and airway structural cells orchestrate asthma pathophysiology, leading to mucus secretion, airway narrowing, and obstruction. Phosphoinositide 3-kinase, a lipid kinase, plays a crucial role in many of the cellular and molecular mechanisms driving asthma pathophysiology and represents an attractive therapeutic target. Here, we summarize the diverse roles of phosphoinositide 3-kinase in the pathogenesis of asthma and discuss novel therapeutic approaches to treatment.

Effects of miRNA-200b on the development of diabetic retinopathy by targeting VEGFA gene

The present study explored the effect of miR-200b on the development of diabetic retinopathy (DR) by targeting vascular endothelial growth factor A (VEGFA) gene. The study populations consisted of 255 DR patients (case group) and 253 healthy people (control group), while the expressions of miR-200b and VEGFA mRNA were detected by quantitative real-time PCR (qRT-PCR). Bioinformatics software and dual-luciferase reporter assay were used to confirm VEGFA as a target gene of miR-200b Also, a total of 70 Wistar male rats were selected and randomly assigned into blank, normal control (NC), miR-200b mimics, miR-200b inhibitors, miR-200b inhibitors + silencing vascular endothelial growth factor A (siVEGFA), and siVEGFA groups (n=10/group) respectively. Streptozotocin (STZ)-induced rat models of DR were successfully established. VEGFA, transforming growth factor-β1 (TGF-β1), hepatocyte growth factor (HGF), and pigment epithelium-derived factor (PEDF) were detected using qRT-PCR and Western blotting. In comparison with the control group, the case group showed lower expression of miR-200b but higher expression of VEGFA mRNA. VEGFA was confirmed as a target gene of miR-200b Rats in the miR-200b mimics and siVEGFA groups exhibited higher expression of PEDF mRNA and protein but lower expressions of VEGFA, TGF-β1, HGF protein, and mRNA than the NC group. There was no remarkable difference in expressions of PEDF, VEGFA, TGF-β1, HGF protein, and mRNA between the miR-200b inhibitors + siVEGFA and NC groups. In conclusion, the present study demonstrated that miR-200b might alleviate DR development by down-regulating its target gene VEGFA.

Direct Effects of Bevacizumab on Rat Conjunctival Fibroblast

Successful cases of treatment of Bevacizumab for preventing scar after trabeculectomy in glaucoma patients encourage us to explore its mechanism. In this study, we primarily isolated conjunctival fibroblast from rat. RT-PCR analysis for the cells implicated that conjunctival fibroblast expressed vascular endothelial growth factor (VEGF) and its receptors. Immunofluorescence staining also showed positive staining for VEGFR-1. Furthermore, growth of fibroblast was significantly inhibited by Bevacizumab at dose of 2.5 mg/ml. Real time PCR results showed after 48 h intervention of 2.5 mg/ml Bevacizumab, the mRNA expressions of VEGF and its receptors decreased compared to the control group (P < 0.05) and Bevacizumab also decreased expression of TGFβ1 and TGFβ2 (P < 0.05). In summary, our finding demonstrated that Bevacizumab could directly act on fibroblast and inhibit VEGF, TGFβ1, and TGFβ2 expression.

Post‑translational modification of CREB‑1 decreases collagen I expression by inhibiting the TGF‑β1 signaling pathway in rat hepatic stellate cells

Liver fibrosis is a reversible wound‑healing response to liver damage. Following liver injury, activated hepatic stellate cells (HSCs) cause excessive deposition of collagen and other components of the extracellular matrix, which may eventually impair liver function. Transforming growth factor‑β1 (TGF‑β1) is critical for the development of liver fibrosis, and acts by activating HSCs, stimulating matrix deposition and inducing other profibrotic responses. Certain studies have demonstrated that the transcription factor, cyclic adenosine monophosphate (cAMP)‑response element binding protein‑1 (CREB‑1) is important in the inhibition of fibrosis; however, the underlying mechanism remains to be elucidated. The present study hypothesized that CREB‑1 inhibits fibrosis via blocking the TGF‑β1 signaling pathway in HSCs. Treatment with the cAMP‑elevating agent, forskolin stimulated CREB‑1 phosphorylation and transcription activation in HSCs. In addition, treatment with the histone deacetylase inhibitor, trichostatin A extended CREB‑1 phosphorylation. The present study used a pRSV‑CREB‑1 expression vector to upregulate CREB‑1 gene expression. The results indicated that activated CREB‑1 reduced TGF‑β1‑stimulated expression of collagen I, activated Smad2/3 and upregulated expression of Smad7. In addition, activated CREB‑1 attenuated the activation of extracellular signal‑regulated kinase 1/2 induced by TGF‑β1, expression of Ras homolog gene family, member A (RhoA) and Rho‑associated coiled‑coil containing protein kinase 1. Thus, post‑translational modification of CREB‑1 inhibited the profibrotic effects of TGF‑β1 in HSCs via Smad‑dependent and ‑independent signaling pathways.

Ameliorative effects of Artemisia argyi Folium extract on 2,4‑dinitrochlorobenzene‑induced atopic dermatitis‑like lesions in BALB/c mice

Artemisia argyi Folium has been used to treat skin diseases, including eczema and dermatitis, in South Korean medicine. The present study investigated the curative effects of Artemisia argyi Folium extract (AAFE) on 2,4‑dinitrochlorobenzene (DNCB)‑induced atopic dermatitis (AD)‑like skin lesions in a BALB/c mouse model. Briefly, the dorsal skin of the BALB/c mice was sensitized three times with DNCB, whereas the ears were challenged twice. Repeated treatment with DNCB induced AD‑like lesions. The effects of AAFE on AD‑like lesions were evaluated by clinical observation, histopathological analysis, immunohistochemistry and enzyme‑linked immunosorbent assay. In addition, reverse transcription‑polymerase chain reaction and western blotting were performed. Treatment with AAFE reduced AD‑like lesions, as determined by clinical observation, histopathological analysis, and detection of the serum levels of histamine, immunoglobulin E and cytokines. With regards to its mechanism of action, AAFE inhibited the phosphorylation of Lck/yes‑related novel tyrosine kinase (Lyn), spleen tyrosine kinase (Syk), mitogen‑activated protein kinases (MAPKs), phosphoinositide 3‑kinase (PI3K)/Akt and IκBα, which have essential roles in the production of various cytokines in lymph nodes. The suppressive activity of AAFE may be due to the inhibition of a series of immunopathological events, including the release of proinflammatory cytokines. The results of the present study strongly suggest that AAFE exerts an anti‑AD effect by inhibiting the Lyn, Syk, MAPKs, PI3K/Akt and IκBα pathways. Therefore, AAFE may be considered an effective herbal remedy for the treatment of AD.

A novel splenic B1 regulatory cell subset suppresses allergic disease through phosphatidylinositol 3-kinase-Akt pathway activation

BACKGROUND

IL-10-producing regulatory B (B10) cells potently suppress allergic diseases, such as contact hypersensitivity (CHS). Splenic B10 cells share overlapping phenotypic markers with CD5⁺ B1 B cells, CD1d^hiCD21⁺CD23^- marginal zone (MZ) B cells, and CD1d^hiCD21⁺CD23⁺ T2-MZ precursor B cells but do not exclusively belong to either subset.

OBJECTIVE

In this study we investigated the signaling mechanisms and a novel phenotypic parameter of B10 cells.

METHOD

We performed microarray analysis comparing IL-10⁺ and IL-10^- B cells. B cell-specific phosphatase and tensin homolog (PTEN)-deficient mice, which exhibit aberrant activation of the phosphatidylinositol 3-kinase (PI3K)-Akt pathway in B cells, were examined.

RESULTS

Microarray analysis revealed that the PI3K-Akt pathway is important for IL-10 production in B cells. PI3K-Akt pathway inhibitors reduced B10 cell numbers in vitro. B10 cell numbers were significantly increased in B cell-specific PTEN-deficient mice. The CHS response was significantly diminished in PTEN-deficient mice. Unexpectedly, splenic B10 cells in these mice were found within the B1 B-cell subset but not within the MZ B-cell subset. In wild-type mice not only MZ B10 cells but also B1-B10 cells were identified in the spleen. In addition, these 2 B10 cell subsets were predominantly found within the CD9⁺CD80⁺ B-cell fraction.

CONCLUSION

A novel splenic B1 regulatory cell subset (B1-B10 cells) was identified. Our findings show that the PI3K-Akt pathway in B cells is critical for B10 cell development and CHS response and that CD9/CD80 coexpression is a novel phenotypic parameter for both MZ-B10 and B1-B10 cells.

Mesenchymal stem cells promote tumor angiogenesis via the action of transforming growth factor β1

Mesenchymal stem cells (MSCs) may influence the growth and metastasis of various human malignancies, including hepatocellular carcinoma (HCC). Therefore, the underlying mechanisms via which MSCs are able to affect malignancies require investigation. In the present study, the potential role of MSC in the angiogenesis of HCC was investigated. A total of 17 nude mouse models exhibiting human HCC were used to evaluate the effects of MSC on angiogenesis. A total of 8 mice were injected with human MSCs via the tail vein, and the remaining 9 mice were injected with phosphate-buffered saline as a control. A total of 35 days subsequent to the injection of MSCs, the microvessel density (MVD) of tumors was evaluated by immunostaining, using cluster of differentiation 31 antibody. The mRNA levels of transforming growth factor (TGF)β1, Smad2 and Smad7 were detected using reverse transcription-quantitative polymerase chain reaction. Protein expression levels of TGFβ1 and vascular endothelial growth factor (VEGF) in tumor tissues were analyzed using ELISA. Compared with controls, MVD in MSC-treated mice was significantly increased (28.00±9.19 vs. 18.11±3.30; P=0.006). The levels of TGFβ1 mRNA in the MSC-treated group were 2.15-fold higher compared with the control group (1.27±0.61 vs. 0.59±0.39; P=0.033), and MVD was higher in the group exhibiting increased TGFβ1 mRNA levels compared with the control group (26.50±9.11 vs. 19.44±6.14; P=0.038). In addition, a close correlation between the expression levels of TGFβ1 and VEGF was identified. The results of the present study suggested that MSCs may be capable of enhancing the angiogenesis of HCC, which may be partly due to the involvement of TGFβ1.

Transforming growth factor-β signaling enhancement by long-term exposure to hypoxia in a tumor microenvironment composed of Lewis lung carcinoma cells

Transforming growth factor‐β (TGF‐β) is a potent growth inhibitor in normal epithelial cells. However, a number of malignant tumors produce excessive amounts of TGF‐β, which affects the tumor‐associated microenvironment by furthering the progression of tumorigenicity. Although it is known that the tumor‐associated microenvironment often becomes hypoxic, how hypoxia influences TGF‐β signaling in this microenvironment is unknown. We investigated whether TGF‐β signaling is influenced by long‐term exposure to hypoxia in Lewis lung carcinoma (LLC) cells. When the cells were exposed to hypoxia for more than 10 days, their morphology was remarkably changed to a spindle shape, and TGF‐β‐induced Smad2 phosphorylation was enhanced. Concomitantly, TGF‐β‐induced transcriptional activity was augmented under hypoxia, although TGF‐β did not influence the activity of a hypoxia‐responsive reporter. Consistently, hypoxia influenced the expression of several TGF‐β target genes. Interestingly, the expressions of TGF‐β type I receptor (TβRI), also termed activin receptor like kinase‐5 (ALK5), and TGF‐β1 were increased under the hypoxic condition. When we monitored the hypoxia‐inducible factor‐1 (HIF‐1) transcriptional activity by use of green fluorescent protein governed by the hypoxia‐responsive element in LLC cells transplanted into mice, TGF‐β‐induced Smad2 phosphorylation was upregulated in vivo. Our results demonstrate that long‐term exposure to hypoxia might alter responsiveness to TGF‐β signaling and affected the malignancy of LLC cells.

Galangin attenuates airway remodelling by inhibiting TGF-β1-mediated ROS generation and MAPK/Akt phosphorylation in asthma

Galangin, a natural flavonol, has attracted much attention for its potential anti-inflammatory properties. However, its role in the regulation of airway remodelling in asthma has not been explored. The present study aimed to elucidate the effects of galangin on chronic inflammation and airway remodelling and to investigate the underlying mechanisms both in vivo and in vitro. Ovalbumin (OVA)-sensitised mice were administered with galangin 30 min before challenge. Our results showed that severe inflammatory responses and airway remodelling occurred in OVA-induced mice. Treatment with galangin markedly attenuated the leakage of inflammatory cells into bronchoalveolar lavage fluid (BALF) and decreased the level of OVA-specific IgE in serum. Galangin significantly inhibited goblet cell hyperplasia, collagen deposition and α-SMA expression. Lowered level of TGF-β1 and suppressed expression of VEGF and MMP-9 were observed in BALF or lung tissue, implying that galangin has an optimal anti-remodelling effect in vivo. Consistently, the TGF-β1-induced proliferation of airway smooth muscle cells was reduced by galangin in vitro, which might be due to the alleviation of ROS levels and inhibition of MAPK pathway. Taken together, the present findings highlight a novel role for galangin as a promising anti-remodelling agent in asthma, which likely involves the TGF-β1-ROS-MAPK pathway.

IMD-4690, a novel specific inhibitor for plasminogen activator inhibitor-1, reduces allergic airway remodeling in a mouse model of chronic asthma via regulating angiogenesis and remodeling-related mediators

Plasminogen activator inhibitor (PAI)-1 is the principal inhibitor of plasminogen activators, and is responsible for the degradation of fibrin and extracellular matrix. IMD-4690 is a newly synthesized inhibitor for PAI-1, whereas the effect on allergic airway inflammation and remodeling is still unclear. We examined the in vivo effects by using a chronic allergen exposure model of bronchial asthma in mice. The model was generated by an immune challenge for 8 weeks with house dust mite antigen, Dermatophagoides pteronyssinus (Dp). IMD-4690 was intraperitoneally administered during the challenge. Lung histopathology, hyperresponsiveness and the concentrations of mediators in lung homogenates were analyzed. The amount of active PAI-1 in the lungs was increased in mice treated with Dp. Administration with IMD-4690 reduced an active/total PAI-1 ratio. IMD-4690 also reduced the number of bronchial eosinophils in accordance with the decreased expressions of Th2 cytokines in the lung homogenates. Airway remodeling was inhibited by reducing subepithelial collagen deposition, smooth muscle hypertrophy, and angiogenesis. The effects of IMD-4690 were partly mediated by the regulation of TGF-β, HGF and matrix metalloproteinase. These results suggest that PAI-1 plays crucial roles in airway inflammation and remodeling, and IMD-4690, a specific PAI-1 inhibitor, may have therapeutic potential for patients with refractory asthma due to airway remodeling.

Proanthocyanidin from Grape Seed Extract Inhibits Airway Inflammation and Remodeling in a Murine Model of Chronic Asthma

Asthma is characterized by airway inflammation and airway remodeling. Our previous study revealed that grape seed proanthocyanidin extract (GSPE) could inhibit asthmatic airway inflammation and airway hyper-responsiveness by down-regulation of inducible nitric oxide synthase in a murine model of acute asthma. The present study aimed to evaluate GSPE's effects on airway inflammation and airway remodeling in a chronic asthmatic model. BALB/c mice were sensitized with ovalbumin (OVA) and then were challenged three times a week for 8 weeks. Airway responsiveness was measured at 24 h after the last OVA challenge. HE staining, PAS staining, and Masson staining were used to observe any airway inflammation in the lung tissue, airway mucus secretion, and subepithelial fibrosis, respectively. The cytokines levels in the lavage fluid (BALF) in addition to the total serum immunoglobulin E (IgE) levels were detected by ELISA. Furthermore, lung collagen contents, α-smooth muscle actin (α-SMA), and transforming growth factor-β1 (TGF-β1) expression in the airway were assessed by hydroxyproline assay, immunohistochemistry, andWestern blot analysis, respectively. GSPE administration significantly suppressed airway resistance as well as reduced the amount of inflammatory cells, especially the eosinophil count, in BALF. Additionally, the GSPE treatment markedly decreased interleukin (IL)-4, IL-13, and vascular endothelial growth factor (VEGF) levels in BALF in addition to the total serum IgE levels. A histological examination demonstrated that GSPE significantly ameliorated allergen-induced lung eosinophilic inflammation and decreased PAS-positive epithelial cells in the airway. The elevated hydroxyproline contents, lung α-SMA contents, and TGF-β1 protein expression that were observed in the OVA mice were also inhibited by GSPE. In conclusion, GSPE could inhibit airway inflammation and airway remodeling in a murine model of chronic asthma, thus providing a potential treatment for asthma.

VEGF-mediated suppression of cell proliferation and invasion by miR-410 in osteosarcoma

MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. The aberrant expression of miRNA has become a major focus in cancer research. This study aimed to investigate the importance of miR-410 in the diagnosis and therapy of osteosarcoma (OS). Western blot analysis showed that the expression of VEGF was higher in Saos-2 and MG-63 cells than that in three other OS cell lines. We also found that miR-410 was lowly expressed and inversely correlated with VEGF expression in OS specimens. Over-expression of miR-410 had a greater repression on VEGF expression than other candidate VEGF-targeting miRNAs. Luciferase reporter assay demonstrated that miR-410 directly decreased VEGF expression by targeting its 3'-untranslated region. Further investigation demonstrated the regulation of miR-410 in OS cells via VEGF. In vitro MTT assay, Transwell, and flow cytometry showed that transfection of the miR-410 expression plasmid inhibited cell proliferation and contributed to apoptosis in OS cells. Moreover, restoration of VEGF reversed the effect of miR-410 on OS cells, and upregulated the expression of phosphorylated AKT. Finally, overexpression of miR-410 also showed a negative effect on tumor growth in vivo. Our findings suggest a cooperative relationship between miR-410 and VEGF in OS cell regulation. This information may help researchers to better understand miRNA regulation in cancer and provide a rationale for developing miRNA-based strategies for OS treatment.

Transforming growth factor β and severe asthma: a perfect storm

Asthma is a chronic inflammatory airway disease involving complex interplay between resident and infiltrative cells, which in turn are regulated by a wide range of host mediators. Identifying useful biomarkers correlating with clinical symptoms and degree of airway obstruction remain important to effective future asthma treatments. Transforming growth factor β (TGF-β) is a major mediator involved in pro-inflammatory responses and fibrotic tissue remodeling within the asthmatic lung. Its role however, as a therapeutic target remains controversial. The aim of this review is to highlight its role in severe asthma including interactions with adaptive T-helper cells, cytokines and differentiation through regulatory T-cells. Associations between TGF-β and eosinophils will be addressed and the effects of genetic polymorphisms of the TGF-β1 gene explored in the context of asthma. We highlight TGF-β1 as a potential future therapeutic target in severe asthma including its importance in identifying emerging clinical phenotypes in asthmatic subjects who may be suitable for individualized therapy through TGF-β modulation.

Role of Klotho, an antiaging protein, in pulmonary fibrosis

Klotho is a recently discovered antiaging protein. Although many researchers are investigating the roles of Klotho in chronic kidney diseases and cancer, however, there are no studies on the roles of Klotho in chronic pulmonary diseases. The purpose of this study was to define the role of Klotho in pulmonary fibrosis using a murine model of ovalbumin (OVA)-induced chronic asthma and in BEAS-2B human bronchial epithelial cells. In an in vivo experiment, mice were sensitized by intraperitoneal injection of OVA (20 μg/mouse), followed 1 week later by an airway challenge with 1 % OVA solution delivered three times a week for 4 weeks. In an in vitro experiment, we investigated the effects of stimulated with interleukin (IL)-4 and tumor necrosis factor (TNF)-α on Klotho protein and VEGF and transforming growth factor (TGF)-β1/Smad3 signaling in BEAS-2B cells. Klotho decreased and VEGF and TGF-β1 levels increased with increasing duration of OVA challenge. Similar findings were found for the expression of these proteins in lung tissue. The collagen content in lung tissue increased with repeated OVA challenge. In the in vitro experiment, Klotho expression decreased and VEGF and TGF-β1/Smad3 expression increased after IL-4 (50 ng/mL) and TNF-α (50 ng/mL) stimulation. Pretreatment with 25, 50, and 100 ng/mL of Klotho protein significantly attenuated the increases in VEGF and TGF-β1/Smad3 expression levels after IL-4 and TNF-α treatment, and reduced α-smooth muscle actin expression in concentration-dependent manner. Klotho protein inhibited the fibrotic response by suppressing VEGF and TGF-β1/Smad3 expression. These results suggest that Klotho protein may be crucial to inhibiting fibrosis associated with chronic airway diseases.

Targeting insulin-like growth factor-I and insulin-like growth factor-binding protein-3 signaling pathways. A novel therapeutic approach for asthma

Insulin-like growth factor (IGF)-I has been recognized to play critical roles in the pathogenesis of asthma, whereas IGF-binding protein (IGFBP)-3 blocks crucial physiologic manifestations of asthma. IGF-I enhances subepithelial fibrosis, airway inflammation, airway hyperresponsiveness, and airway smooth muscle hyperplasia by interacting with various inflammatory mediators and complex signaling pathways, such as intercellular adhesion molecule-1, and the hypoxia-inducible factor/vascular endothelial growth factor axis. On the other hand, IGFBP-3 decreases airway inflammation and airway hyperresponsiveness through IGFBP-3 receptor-mediated activation of caspases, which subsequently inhibits NF-κB signaling pathway. It also inhibits the IGF-I/hypoxia-inducible factor/vascular endothelial growth factor axis via IGF-I-dependent and/or IGF-I-independent mechanisms. This Translational Review summarizes the role of IGF-I and IGFBP-3 in the context of allergic airway disease, and discusses the therapeutic potential of various strategies targeting the IGF-I and IGFBP-3 signaling pathways for the management of asthma.

Effects of inhalational anaesthetics in experimental allergic asthma

We evaluated whether isoflurane, halothane and sevoflurane attenuate the inflammatory response and improve lung morphofunction in experimental asthma. Fifty-six BALB/c mice were sensitised and challenged with ovalbumin and anaesthetised with isoflurane, halothane, sevoflurane or pentobarbital sodium for one hour. Lung mechanics and histology were evaluated. Gene expression of pro-inflammatory (tumour necrosis factor-α), pro-fibrogenic (transforming growth factor-β) and pro-angiogenic (vascular endothelial growth factor) mediators, as well as oxidative process modulators, were analysed. These modulators included nuclear factor erythroid-2 related factor 2, sirtuin, catalase and glutathione peroxidase. Isoflurane, halothane and sevoflurane reduced airway resistance, static lung elastance and atelectasis when compared with pentobarbital sodium. Sevoflurane minimised bronchoconstriction and cell infiltration, and decreased tumour necrosis factor-α, transforming growth factor-β, vascular endothelial growth factor, sirtuin, catalase and glutathione peroxidase, while increasing nuclear factor erythroid-2-related factor 2 expression. Sevoflurane down-regulated inflammatory, fibrogenic and angiogenic mediators, and modulated oxidant-antioxidant imbalance, improving lung function in this model of asthma.

Bangpungtongseong-san, a traditional herbal medicine, attenuates chronic asthmatic effects induced by repeated ovalbumin challenge

Airway remodeling is characterized by airway wall thickening, subepithelial fibrosis, increased smooth muscle mass, angiogenesis and increased mucus secretion, which can lead to chronic and obstinate asthma and can obstruct pulmonary function. In this study, the effects of Bangpungtongseong-san water extract (BPTS) on airway remodeling were examined using a murine model of bronchial asthma induced by ovalbumin (OVA) challenge. We focused on the effects of BPTS on the regulation of chronic asthma. BALB/c mice were randomly assigned to 5 groups, some of which were sensitized and challenged with OVA for 4 weeks. After the final ovalbumin challenge, typical asthma-like morphological changes were observed in the lung tissue with hematoxylin and eosin staining, periodic acid-Schiff, as well as with Masson's trichrome staining. The levels of transforming growth factor-β1 (TGF-β1) and Smad3 were assessed by immunohistochemistry and western blot analysis. The expression levels of vascular endothelial growth factor (VEGF) and adhesion molecules, such as intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were also detected by western blot analysis. Our results revealed that BPTS reduced the OVA-induced increase in the infiltration of leukocytes, mucus hyperplasia and collagen deposition. Compared with the OVA-challenged group, the BPTS group had lower expression levels of adhesion molecules, TGF-β1, Smad3 and VEGF proteins in the lung tissues. The results of the current study suggest that BPTS prevents asthma airway remodeling in chronic asthma by inhibiting the activation of the TGF-β1-Smad3-signaling pathway, as well as the expression of VEGF and adhesion molecules. BPTS may thus be a potential drug for the treatment of patients with changes that occur in the airways due to severe asthma.

The herbal formula CGX ameliorates the expression of vascular endothelial growth factor in alcoholic liver fibrosis

ETHNOPHARMACOLOGIC RELEVANCE

The Chunggan extract (CGX) is a traditional herbal formula prescribed for patients suffering from various liver diseases, including alcoholic liver disease, in which the mechanism of CGX action remains unclear. This study aimed to investigate the anti-hepatic fibrosis effects of CGX and its underlying mechanisms in alcohol-induced rat livers.

MATERIALS AND METHODS

To elucidate the mechanism of action of CGX, we evaluated gene expression profiles in the livers of rats treated with 30% alcohol and anti-fibrotic doses of CGX of 100 and 200 mg/kg/day at 1 day, and 2 and 4 weeks using microarrays. The mRNA and protein expression levels of vascular endothelial growth factor (VEGF), one of the candidate genes selected in this study, in alcohol-induced rat livers were measured by real-time PCR and enzyme-linked immunosorbent assays, respectively.

RESULTS

We identified 4128 genes as differentially expressed by at least twofold between alcohol-only- and alcohol-CGX-fed rats at various doses and time points, compared to naïve control animals. Twenty-three of these genes were associated with liver fibrosis and oxidative stress based on the GeneCards database, resulting in p<0.05 by ANOVA between the alcohol-only and alcohol-CGX groups. Especially, Vegf was decreased in CGX 200 mg/kg/day-fed rat livers at all time points evaluated, and mRNA and protein levels at the 4-week time point were validated.

CONCLUSION

These gene expression profiles provide a better understanding of the mechanisms underlying the anti-fibrotic effects of CGX. Suppression of VEGF may play a critical role in anti-fibrotic action of CGX in alcoholic liver injury.

Effects of montelukast on subepithelial/peribronchial fibrosis in a murine model of ovalbumin induced chronic asthma

Montelukast, a leukotriene receptor antagonist, is used commercially as a maintenance treatment for asthma and to relieve allergic symptoms. In this study, we evaluated the protective effects of montelukast against the airway inflammation and fibrosis using a murine model of ovalbumin (OVA) induced chronic asthma. The animals received OVA challenge three times a week for 4 weeks. Montelukast (30 mg/kg) was administrated orally once a day for 4 weeks. The administration of montelukast caused a reduction in elevated interleukin (IL)-4, IL-13, eotaxin, immunoglobulin (Ig), inflammatory cell infiltration into the airways, and mucus production after repeated OVA challenges. To investigate the antifibrotic mechanism of montelukast, we examined the expression of profibrotic mediators, including vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, and Smad3 proteins in the lung tissue using western blotting and immunohistochemistry. The administration of montelukast reduced the overexpression of profibrotic proteins in the lung tissue, which was confirmed by immnunohistochemistry. These results are consistent with a histopathological examination of lung tissue with Masson's trichrome stain. In conclusion, the administration of montelukast reduced airway inflammation and pulmonary fibrosis by reducing the release of Th2 cytokines and the expression of VEGF, TGF-β1/Smad3 in the lung tissue.

Modulation of angiogenesis by genetic manipulation of ATF4 in mouse model of oxygen-induced retinopathy [corrected]

PURPOSE

The activation of the unfolded protein response (UPR) and an increase in activating transcription factor 4 (ATF4) has been previously reported in the diabetic retina. Despite this, a direct link between ATF4 and the degree of proliferative retinopathy has not been demonstrated to date. Therefore, the objective of this study was to determine whether ATF4 deficiency could reduce neovascularization in mice with oxygen-induced retinopathy (OIR).

METHODS

We induced OIR in C57BL/6, ATF4(+/-), and endoplasmic reticulum stress-activated indicator (ERAI) mice and used quantitative RT-PCR and Western blot analysis to evaluate relative gene and protein expression. Histology and microscopy were used to calculate the extent of neovascularization in flat-mounted retinas.

RESULTS

Experimental data revealed Xbp1 splicing in the retinal ganglia cells, outer plexiform layer, inner nuclear layer, and outer nuclear layer and in pericytes of postdevelopment day 17 ERAI OIR mice, confirming the activation of IRE1 UPR signaling. In naive ATF4-deficient mice, we also observed an elevation in UPR-associated and vascular-associated gene expression (Bip, Atf6, Hif1a, Pik3/Akt, Flt1/Vegfa, and Tgfb1), which may have contributed to the alleviation of hypoxia-driven neovascularization in experimental ATF4(+/-) retinas. The OIR ATF4(+/-) retinas demonstrated reprogramming of the UPR seen at both the mRNA (Atf6 and Bip) and protein (pATF6 and peIf2α) levels, as well as a reduction in vascularization-associated gene expression (Flt1, Vegf1, Hif1, and Tgb1). These changes corresponded to the decline in the rate of neovascularization.

CONCLUSIONS

Our study validates ATF4 as a prospective therapeutic target to inhibit neovascularization in proliferative retinopathy.

Ojeok-san, a traditional Korean herbal medicine attenuates airway inflammation and pulmonary fibrosis induced by repeated ovalbumin challenge

ETHNOPHARMACOLOGICAL EVIDENCE

Ojeok-san, a traditional Korean herbal medicine, is widely used in China, Japan and Korea for treatment of the common cold, pain and fever.

AIM OF THE STUDY

In this study, we investigated the protective effects of Ojeok-san aqueous extract (OJS) against pulmonary fibrosis using a chronic asthma murine model.

METHODS

Mice were sensitized by intraperitoneal injection of ovalbumin (OVA), followed 1 weeks later by an airway challenge with OVA delivered three times a week for 4 weeks. OJS (50mg/kg or 100mg/kg) was also administered by oral gavage once a day for 4 weeks.

RESULTS

OJS significantly reduced interleukin (IL)-4, IL-13, eotaxin, immunoglobulin E and the number of inflammatory cells in bronchoalveolar lavage fluid; in addition, it reduced inflammatory cell infiltration and mucus production in the respiratory tract. We found that OJS also attenuated the OVA-induced increase in vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1 and Smad3 protein in lung tissue, as determined by Western analysis and immunohistochemistry. These inhibitory effects of OJS were accompanied by a reduction in pulmonary fibrosis, consistent with the histopathology of lung tissue stained with Masson's trichrome.

CONCLUSION

Administration of OJS reduced the airway inflammation and pulmonary fibrosis, as well as the level of T helper type 2 cytokines and VEGF and TGF-β1/Smad3 expressions in lung tissue. These results suggest that OJS might represent a useful new oral therapy for the treatment of chronic asthma.

Vascular endothelial growth factor aggravates fibrosis and vasculopathy in experimental models of systemic sclerosis

OBJECTIVES

High levels of vascular endothelial growth factor (VEGF), a key angiogenic factor, are present in patients with systemic sclerosis (SSc), but its role in the pathogenesis of fibrosis and its contribution to the disturbed angiogenesis of SSc remains hypothetical.

METHODS

Mono (+/-) and double (+/+) VEGF transgenic (tg) mice and their wildtype (wt) controls were analysed. The bleomycin model was applied to VEGF tg mice to evaluate effects of VEGF under proinflammatory conditions. Additionally, tight skin (TSK) 1/VEGF+/+ mice were generated to mimic later non-inflammatory stages of SSc.

RESULTS

VEGF+/+, but not VEGF+/- tg mice, spontaneously developed significant skin fibrosis, indicating profibrotic effect of VEGF in a gene-dosing manner. In the proinflammatory bleomycin model, the profibrotic effect became more pronounced with induction of skin fibrosis in VEGF+/- tg mice and even more enhanced fibrosis in VEGF+/+ tg mice. Analysis in TSK1/VEGF+/+ mice showed similar profibrotic effects of VEGF also under non-inflammatory in vivo conditions. In vitro analysis revealed that VEGF is able to directly induce collagen synthesis in dermal fibroblasts. Additionally, there was an inverse gene-dosing effect on the efficacy of angiogenesis in that a higher number of microvessels was observed in VEGF+/- tg mice than in VEGF+/+ tg mice.

CONCLUSIONS

These data provide the first evidence for VEGF as a novel molecular link between fibrosis and vasculopathy in the pathogenesis of SSc. They suggest that high levels of VEGF potently induce fibrosis in inflammatory and non-inflammatory stages, and also contribute to the relatively insufficient angiogenesis characteristic for SSc.

Role of vascular endothelial growth factor antagonism on airway remodeling in asthma

BACKGROUND

Vascular endothelial growth factor (VEGF) is an important mediator of the neoangiogenesis component of remodeling in asthma.

OBJECTIVE

To evaluate the influence of VEGF blockage on airway remodeling, specifically epithelium thickness, subepithelial smooth muscle thickness, number of mast and goblet cells, and basement membrane thickness, in a mouse model of chronic asthma.

METHODS

We used 30 BALB/c mice. The control group was not exposed to ovalbumin or any medication (group 1). Other groups were exposed to intraperitoneal and inhaled ovalbumin to achieve chronic asthma. Each of these groups received intraperitoneal saline (group 2), intraperitoneal dexamethasone (group 3), or intraperitoneal bevacizumab (group 4). Histomorphologic examination for epithelium thickness, subepithelial smooth muscle thickness, number of mast and goblet cells, and basement membrane thickness was performed from the middle zone of the left lung.

RESULTS

Treatment with anti-VEGF caused significant reduction in epithelial, subepithelial muscle, and basement membrane thickness compared with untreated asthmatic mice (P = .001, P = .03, and P = .009, respectively). Goblet and mast cell numbers were significantly lower in mice treated with anti-VEGF than in untreated mice (P = .02 and P = .007, respectively). Dexamethasone treatment resulted in improvement of all histomorphologic markers, except goblet cell number. Influences of dexamethasone and anti-VEGF on epithelial and basement membrane thickness and mast and goblet cell numbers did not differ (P > .05), but subepithelial muscle layer was thinner in the former (P = .003).

CONCLUSION

VEGF blockage may provide adjunctive therapeutic options as steroid-sparing agents for more effective treatment of remodeling in asthma.

VEGF induces TGF-β1 expression and myofibroblast transformation after glaucoma surgery

Subconjunctival fibrosis at the surgical site determines the outcome of glaucoma surgery. Myofibroblast transformation has a significant role in fibrosis, and vascular endothelial growth factor (VEGF) is reported to trigger myofibroblast transformation by inducing transforming growth factor (TGF)-β1. In the present study, we used IHC, Western blot analysis, enzyme-linked immunosorbent assay, and electron microscopy to determine the contribution of VEGF to myofibroblast transformation in subconjunctival fibrosis after glaucoma surgery. A rabbit trabeculectomy model was generated, and VEGF stimulation or VEGF inhibition was performed during surgery. VEGF stimulation induced TGF-β1 expression in a dose-dependent manner. Down-regulation of epithelial markers (E-cadherin and β-catenin) and up-regulation of mesenchymal marker (α-smooth muscle actin) were observed in the subconjunctival layers after trabeculectomy with VEGF stimulation. Up-regulations of Smad and Snail, which play a central role in myofibroblast transformation, were observed in the conjunctival and subconjunctival layers at the site of trabeculectomy. Electron microscopy revealed changes of the conjunctival epithelial cells, especially the presence of myofilaments and increased rough endoplasmic reticulum in the cytoplasm. Myofibroblast transformation was activated by VEGF stimulation and decreased by VEGF inhibition. These findings suggest that VEGF potentially affected the TGF-β1/Smad/Snail pathway, thereby triggering myofibroblast transformation. Therapeutic approaches modulating VEGF may control myofibroblast transformation and reduce subconjunctival fibrosis after glaucoma surgery.

Junctional adhesion molecule-A regulates vascular endothelial growth factor receptor-2 signaling-dependent mouse corneal wound healing

Inflammation and angiogenesis are integral parts of wound healing. However, excessive and persistent wound-induced inflammation and angiogenesis in an avascular tissue such as the cornea may be associated with scarring and visual impairment. Junctional adhesion molecule A (Jam-A) is a tight junction protein that regulates leukocyte transmigration as well as fibroblast growth factor-2 (FGF-2)-induced angiogenesis. However its function in wound-induced inflammation and angiogenesis is still unknown. In this study, we report spontaneous corneal opacity in Jam-A deficient mice associated with inflammation, angiogenesis and the presence of myofibroblasts. Since wounds and/or corneal infections cause corneal opacities, we tested the role of Jam-A in wound-induced inflammation, angiogenesis and scarring by subjecting Jam-A deficient mice to full thickness corneal wounding. Analysis of these wounds demonstrated increased inflammation, angiogenesis, and increased number of myofibroblasts thereby indicating that Jam-A regulates the wound-healing response by controlling wound-induced inflammation, angiogenesis and scarring in the cornea. These effects were not due to inflammation alone since the inflammation-induced wound-healing response in Jam-A deficient mice was similar to wild type mice. In order to determine the molecular mechanism associated with the observed aberrant corneal wound healing in Jam-A deficient mice, we assessed the expression of the components of vascular endothelial growth factor A (VEGF-A)/vascular endothelial growth factor receptor- 2(VEGFR-2) signaling pathway. Interestingly, we observed increased levels of VEGF-A mRNA in Jam-A deficient eyes. We also observed nuclear localization of phosphorylated SMAD3 (pSMAD3) indicative of TGFβ pathway activation in the Jam-A deficient eyes. Furthermore the increased wound-induced corneal inflammation, angiogenesis, and scarring in Jam-A deficient mice was attenuated by treatment with DC101, an anti-vascular endothelial growth factor receptor-2 (VEGFR-2) antibody. Our results suggest that in the absence of Jam-A, the VEGF-A/VEGFR-2 pathway is upregulated, thereby augmenting wound induced corneal inflammation, angiogenesis, and myofibroblast accumulation leading to scarring.