VEGFR1-tyrosine kinase signaling in pulmonary fibrosis

Molecular mechanism of Flt-1 protein and the regulation of monocytes modulate endothelial cell in wound healing sites via PGF/FLT1 signaling

The purpose of this study was to investigate the mechanism of action of the Flt-1 protein molecule during wound healing and to analyze how monocytes regulate endothelial cells at the wound healing site through the placental growth factor/Fms-like tyrosine kinase 1 (PGF/FLT1) signaling pathway. In this study, the PGF and Flt-1 knockdown mice models were constructed to observe the changes of wound healing. The expression of Flt-1 mRNA and protein during wound healing in human and mice biopsies was detected by qPCR and immunofluorescence. The interaction between monocytes and endothelial cells, especially the role of proteins and RNAs in the PGF/FLT1 signaling pathway in this process, was also analyzed. The results showed that the expression of Flt-1 protein was significantly up-regulated during wound healing, especially in endothelial cells, which promotes the proliferation and migration of endothelial cells, accelerates angiogenesis, and thus accelerates the rate of wound healing. In contrast, Flt-1 knockdown suppresses these processes. Monocytes can activate the FLT1 receptor on endothelial cells by secreting PGF, and then promote the proliferation and migration of endothelial cells.

Angiogenesis and Microvascular Permeability

Angiogenesis, the formation of new blood microvessels, is a necessary physiological process for tissue generation and repair. Sufficient blood supply to the tissue is dependent on microvascular density, while the material exchange between the circulating blood and the surrounding tissue is controlled by microvascular permeability. We thus begin this article by reviewing the key signaling factors, particularly vascular endothelial growth factor (VEGF), which regulates both angiogenesis and microvascular permeability. We then review the role of angiogenesis in tissue growth (bone regeneration) and wound healing. Finally, we review angiogenesis as a pathological process in tumorigenesis, intraplaque hemorrhage, cerebral microhemorrhage, pulmonary fibrosis, and hepatic fibrosis. Since the glycocalyx is important for both angiogenesis and microvascular permeability, we highlight the role of the glycocalyx in regulating the interaction between tumor cells and endothelial cells (ECs) and VEGF-containing exosome release and uptake by tumor-associated ECs, all of which contribute to tumorigenesis and metastasis.

hAMSCs regulate EMT in the progression of experimental pulmonary fibrosis through delivering miR-181a-5p targeting TGFBR1

BACKGROUND

Pulmonary fibrosis (PF) is a common and multidimensional devastating interstitial lung disease. The development of novel and more effective interventions for PF is an urgent clinical need. A previous study has found that miR-181a-5p plays an important role in the development of PF, and human amniotic mesenchymal stem cells (hAMSCs) exert potent therapeutic potential on PF. However, whether hAMSCs act on PF by delivering miR-181a-5p and its detailed mechanism still remain unknown. Thus, this study was designed to investigate the underlying possible mechanism of hAMSCs on PF in bleomycin (BLM)-induced mouse PF model, and a co-culture system of hAMSCs and A549 cells epithelial mesenchymal transition (EMT) model, focusing on its effects on collagen deposition, EMT, and epithelial cell cycle regulation.

METHODS

hAMSCs with different miR-181a-5p expression levels were constructed. BLM (4 mg/kg) was used to create a PF model, while TGF-β1 was used to induce A549 cells to construct an EMT model. Furthermore, the effects of different miR-181a-5p expression in hAMSCs on collagen deposition and EMT during lung fibrosis were assessed in vivo and in vitro.

RESULTS

We found that hAMSCs exerted anti-fibrotic effect in BLM-induced mouse PF model. Moreover, hAMSCs also exerted protective effect on TGFβ1-induced A549 cell EMT model. Furthermore, hAMSCs ameliorated PF by promoting epithelial cell proliferation, reducing epithelial cell apoptosis, and attenuating EMT of epithelial cells through paracrine effects. hAMSCs regulated EMT in PF through delivering miR-181a-5p targeting TGFBR1.

CONCLUSIONS

Our findings reveal for the first time that hAMSCs inhibit PF by promoting epithelial cell proliferation, reducing epithelial cell apoptosis, and attenuating EMT. Mechanistically, the therapeutic effect of hMASCs on PF is achieved through delivering miR-181a-5p targeting TGFBR1.

Urban airborne PM2.5 induces pulmonary fibrosis through triggering glycolysis and subsequent modification of histone lactylation in macrophages

Airborne fine particulate matter (PM2.5) can cause pulmonary inflammation and even fibrosis, however, the underlying molecular mechanisms of the pathogenesis of PM2.5 exposure have not been fully appreciated. In the present study, we explored the dynamics of glycolysis and modification of histone lactylation in macrophages induced by PM2.5-exposure in both in vivo and in vitro models. Male C57BL/6 J mice were anesthetized and administrated with PM2.5 by intratracheal instillation once every other day for 4 weeks. Mouse RAW264.7 macrophages and alveolar epithelial MLE-12 cells were treated with PM2.5 for 24 h. We found that PM2.5 significantly increased lactate dehydrogenase (LDH) activities and lactate contents, and up-regulated the mRNA expression of key glycolytic enzymes in the lungs and bronchoalveolar lavage fluids of mice. Moreover, PM2.5 increased the levels of histone lactylation in both PM2.5-exposed lungs and RAW264.7 cells. The pro-fibrotic cytokines secreted from PM2.5-treated RAW264.7 cells triggered epithelial-mesenchymal transition (EMT) in MLE-12 cells through activating transforming growth factor-β (TGF-β)/Smad2/3 and VEGFA/ERK pathways. In contrast, LDHA inhibitor (GNE-140) pretreatment effectively alleviated PM2.5-induced pulmonary inflammation and fibrosis via inhibiting glycolysis and subsequent modification of histone lactylation in mice. Thus, our findings suggest that PM2.5-induced glycolysis and subsequent modification of histone lactylation play critical role in the PM2.5-associated pulmonary fibrosis.

MiR-199a-5p inhibits dermal papilla cells proliferation by regulating VEGFA expression in cashmere goat

Hair follicles undergo a renewal cycle consisting of anagen, telogen and catagen stages. MicroRNA (miRNA) plays a crucial role in this process. Recent studies have shown that miR-199a-5p, which exhibits differential expression between anagen and telogen stages in the hair follicle cycle of cashmere goats, inhibits the proliferation of various cell types, including skin keratinocytes and vascular endothelial cells. Since the proliferation of dermal papilla cells (DPCs) is a key factor in the hair follicle cycle, we utilized DPCs to investigate the function and molecular mechanism of miR-199a-5p in cashmere goats. Our functional analysis revealed that miR-199a-5p significantly suppressed cell viability and proliferation of DPCs, as evidenced by MTT, EdU and RT-qPCR methods. Subsequently, we investigated the regulatory mechanism of miR-199a-5p. Through bioinformatics analysis, a potential correlation between lnc102173187 and miR-199a-5p was predicted. However, the dual luciferase reporter assay revealed no interaction between lnc102173187 and miR-199a-5p. Further investigation using dual-luciferase reporter assay, RT-qPCR, and western blot results confirmed that VEGFA was the target gene of miR-199a-5p from. The functional experiment demonstrated that VEGFA promoted the proliferation of DPCs, and antagonized the inhibitory effect of miR-199a-5p on DPCs proliferation. Taken together, this research revealed the role of miR-199a-5p and VEGFA on the proliferation of dermal papilla cells in cashmere goat, which would enrich the theoretical basis for hair follicle development, and could also serve as a marker cofactor to play an important reference and guidance role in the breeding, improvement and optimization of cashmere goat breeds.

Knockdown of lncRNA PVT1 protects human trabecular meshwork cells against H2O2-induced injury via the regulation of the miR-29a-3p/VEGF/MMP-2 axis

Purpose

Human trabecular meshwork cell (HTMC) dysfunction results in imbalanced aqueous humor inflow and outflow, leading to an increase in intraocular pressure (IOP). Uncontrolled high IOP can promote the occurrence of glaucoma, an irreversible optic neuropathy. Here, we explored whether the long non-coding RNA plasmacytoma variant translocation 1 (lncRNA PVT1)/microRNA-29a-3p (miR-29a-3p) axis could ameliorate HTMC dysfunction under oxidative stress by modulating the expression of the proangiogenic factor vascular endothelial growth factor (VEGFA) and the profibrotic factor metalloproteinase-2 (MMP-2).

Methods

HTMCs were cultured under H2O2-induced oxidative stress for 48 h. The expression of lncRNA PVT1, miR-29a-3p, VEGFA, MMP-2, intracellular adhesion molecule-1 (ICAM-1), and alpha-smooth muscle actin (α-SMA) was detected by reverse transcription quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence. Interference experiments were conducted via the transfection of HTMCs with small interfering RNA (siRNA) targeting lncRNA PVT1 or miR-29a-3p mimics. A luciferase reporter assay was undertaken to identify the presence of a miR-29a-3p binding site in lncRNA PVT1. Flow cytometry and Transwell and Cell Counting Kit-8 assays were employed to evaluate HTMC functions under oxidative stress with different treatments.

Results

In HTMCs, the expression of lncRNA PVT1 was induced by H2O2 treatment, whereas that of miR-29a-3p was inhibited. The levels of angiogenic factors (VEGFA, ICAM-1) and fibrosis-associated mediators (MMP-2, α-SMA) were upregulated in HTMCs under oxidative stress. The siRNA-mediated suppression of lncRNA PVT1 or the upregulation of miR-29a-3p significantly suppressed the expression of VEGFA, MMP-2, ICAM-1, and α-SMA. A luciferase reporter assay confirmed that lncRNA PVT1 directly targeted miR-29a-3p and acted as a miR-29a-3p sponge. The knockdown of lncRNA PVT1 restored the level of miR-29a-3p in H2O2-treated HTMCs, thereby inhibiting VEGFA and MMP-2, its target mRNAs. HTMC dysfunction, including increased apoptosis and decreased cell mobility and viability, could be effectively ameliorated by lncRNA PVT1 downregulation or miR-29a-3p overexpression under oxidative stress.

Conclusion

LncRNA PVT1 has potential as a therapeutic target for inhibiting VEGFA and MMP-2, thus protecting HTMCs, suppressing the progression of fibrosis, and, consequently, improving the outcome of glaucoma filtration surgery.

Emerging opportunities to treat idiopathic pulmonary fibrosis: Design, discovery, and optimizations of small-molecule drugs targeting fibrogenic pathways

Idiopathic pulmonary fibrosis (IPF) is the most common fibrotic form of idiopathic diffuse lung disease. Due to limited treatment options, IPF patients suffer from poor survival. About ten years ago, Pirfenidone (Shionogi, 2008; InterMune, 2011) and Nintedanib (Boehringer Ingelheim, 2014) were approved, greatly changing the direction of IPF drug design. However, limited efficacy and side effects indicate that neither can reverse the process of IPF. With insights into the occurrence of IPF, novel targets and agents have been proposed, which have fundamentally changed the treatment of IPF. With the next-generation agents, targeting pro-fibrotic pathways in the epithelial-injury model offers a promising approach. Besides, several next-generation IPF drugs have entered phase II/III clinical trials with encouraging results. Due to the rising IPF treatment requirements, there is an urgent need to completely summarize the mechanisms, targets, problems, and drug design strategies over the past ten years. In this review, we summarize known mechanisms, target types, drug design, and novel technologies of IPF drug discovery, aiming to provide insights into the future development and clinical application of next-generation IPF drugs.

Integrating inflammatory biomarker analysis and artificial-intelligence-enabled image-based profiling to identify drug targets for intestinal fibrosis

Intestinal fibrosis, often caused by inflammatory bowel disease, can lead to intestinal stenosis and obstruction, but there are no approved treatments. Drug discovery has been hindered by the lack of screenable cellular phenotypes. To address this, we used a scalable image-based morphology assay called Cell Painting, augmented with machine learning algorithms, to identify small molecules that could reverse the activated fibrotic phenotype of intestinal myofibroblasts. We then conducted a high-throughput small molecule chemogenomics screen of approximately 5,000 compounds with known targets or mechanisms, which have achieved clinical stage or approval by the FDA. By integrating morphological analyses and AI using pathologically relevant cells and disease-relevant stimuli, we identified several compounds and target classes that are potentially able to treat intestinal fibrosis. This phenotypic screening platform offers significant improvements over conventional methods for identifying a wide range of drug targets.

Integrative multi-omics analysis reveals novel idiopathic pulmonary fibrosis endotypes associated with disease progression

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is characterized by the accumulation of extracellular matrix in the pulmonary interstitium and progressive functional decline. We hypothesized that integration of multi-omics data would identify clinically meaningful molecular endotypes of IPF.

METHODS

The IPF-PRO Registry is a prospective registry of patients with IPF. Proteomic and transcriptomic (including total RNA [toRNA] and microRNA [miRNA]) analyses were performed using blood collected at enrollment. Molecular data were integrated using Similarity Network Fusion, followed by unsupervised spectral clustering to identify molecular subtypes. Cox proportional hazards models tested the relationship between these subtypes and progression-free and transplant-free survival. The molecular subtypes were compared to risk groups based on a previously described 52-gene (toRNA expression) signature. Biological characteristics of the molecular subtypes were evaluated via linear regression differential expression and canonical pathways (Ingenuity Pathway Analysis [IPA]) over-representation analyses.

RESULTS

Among 232 subjects, two molecular subtypes were identified. Subtype 1 (n = 105, 45.3%) and Subtype 2 (n = 127, 54.7%) had similar distributions of age (70.1 +/- 8.1 vs. 69.3 +/- 7.6 years; p = 0.31) and sex (79.1% vs. 70.1% males, p = 0.16). Subtype 1 had more severe disease based on composite physiologic index (CPI) (55.8 vs. 51.2; p = 0.002). After adjusting for CPI and antifibrotic treatment at enrollment, subtype 1 experienced shorter progression-free survival (HR 1.79, 95% CI 1.28,2.56; p = 0.0008) and similar transplant-free survival (HR 1.30, 95% CI 0.87,1.96; p = 0.20) as subtype 2. There was little agreement in the distribution of subjects to the molecular subtypes and the risk groups based on 52-gene signature (kappa = 0.04, 95% CI= -0.08, 0.17), and the 52-gene signature risk groups were associated with differences in transplant-free but not progression-free survival. Based on heatmaps and differential expression analyses, proteins and miRNAs (but not toRNA) contributed to classification of subjects to the molecular subtypes. The IPA showed enrichment in pulmonary fibrosis-relevant pathways, including mTOR, VEGF, PDGF, and B-cell receptor signaling.

CONCLUSIONS

Integration of transcriptomic and proteomic data from blood enabled identification of clinically meaningful molecular endotypes of IPF. If validated, these endotypes could facilitate identification of individuals likely to experience disease progression and enrichment of clinical trials.

TRIAL REGISTRATION

NCT01915511.

Non-Coding RNAs in Pulmonary Diseases: Comparison of Different Airway-Derived Biosamples

Due to their structural conservation and functional role in critical signalling pathways, non-coding RNA (ncRNA) is a promising biomarker and modulator of pathological conditions. Most research has focussed on the role of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules have been investigated both in a cellular and an extracellular context. Sources of ncRNAs may include organ-specific body fluids. Therefore, studies on ncRNAs in respiratory diseases include those on sputum, bronchoalveolar lavage fluid (BALF) and exhaled breath condensate (EBC). It is worth identifying the limitations of these biosamples in terms of ncRNA abundance, processing and diagnostic potential. This review describes the progress in the literature on the role of ncRNAs in the pathogenesis and progression of severe respiratory diseases, including cystic fibrosis, asthma and interstitial lung disease. We showed that there is a deficit of information on lncRNAs and circRNAs in selected diseases, despite attempts to functionally bind them to miRNAs. miRNAs remain the most well-studied, but only a few investigations have been conducted on the least invasive biosample material, i.e., EBC. To summarise the studies conducted to date, we also performed a preliminary in silico analysis of the reported miRNAs, demonstrating the complexity of their role and interactions in selected respiratory diseases.

Radotinib attenuates TGFβ -mediated pulmonary fibrosis in vitro and in vivo: exploring the potential of drug repurposing

BACKGROUND

Tyrosine kinase (TK) plays a crucial role in the pathogenesis of idiopathic pulmonary fibrosis. Here, we aimed to investigate whether radotinib (Rb) could inhibit pulmonary fibrosis by inhibiting TK in vitro and in vivo.

METHODS

The antifibrotic effects of Rb in transforming growth factor-β (TGF-β)1-stimulated A549 cells were determined using real-time polymerase chain reaction, western blotting, and immunocytochemistry assays. Rb inhibition of bleomycin-induced lung fibrosis in Sprague Dawley (SD) rats was determined by histopathological and​ immunohistochemical analyses. Rb-interfering metabolites were analyzed using LC-MS/MS.

RESULTS

Rb concentrations of up to 1000 nM did not affect the viability of A549 cells, but Rb (30 nM) significantly reduced expression of TGF-β1 (10 ng/mL)-induced ECM factors, such as Snail, Twist, and F-actin. Rb also regulated TGF-β1-overexpressed signal cascades, such as fibronectin and α-smooth muscle actin. Furthermore, Rb attenuated the phosphorylation of Smad2 and phosphorylation of kinases, such as, extracellular signal-regulated kinase, and protein kinase B. In the inhibitory test against bleomycin (5 mg/kg)-induced lung fibrosis, the Rb (30 mg/kg/daily)-treated group showed a half-pulmonary fibrosis region compared to the positive control group. In addition, Rb significantly reduced collagen type I and fibronectin expression in the bleomycin-induced fibrotic region of SD rats. Further, the identified metabolite pantothenic acid was not altered by Rb.

CONCLUSION

Taken together, these results indicate that Rb inhibits TGF-β1-induced pulmonary fibrosis both in vitro and in vivo. These findings suggest that Rb may be an effective treatment for pulmonary fibrosis-related disorders and idiopathic pulmonary fibrosis.

Decorating hexahistidine-metal assemblies with tyrosine enhances the ability of proteins to pass through corneal biobarriers

In recent decades, the use of protein drugs has increased dramatically for almost every clinical indication, including autoimmunity and cancer infection, given their high specificity and limited side effects. However, their easy deactivation by the surrounding microenvironment and limited ability to pass through biological barriers pose large challenges to the use of these agents for therapeutic effects; these deficits could be greatly improved by nanodelivery using platforms with suitable physicochemical properties. Here, to assess the effect of the hydrophilicity of nanoparticles on their ability to penetrate biological barriers, the hydrophobic amino acid tyrosine (Y) was decorated onto hexahistidine peptide, and two nanosized YHmA and HmA particles were generated, in which Avastin (Ava, a protein drug) was encapsulated by a coassembly strategy. In vitro and in vivo tests demonstrated that these nanoparticles effectively retained the bioactivity of Ava and protected Ava from proteinase K hydrolysis. Importantly, YHmA displayed a considerably higher affinity to the ocular surface than HmA, and YHmA also exhibited the ability to transfer proteins across the barriers of the anterior segment, which greatly improved the bioavailability of the encapsulated Ava and produced surprisingly good therapeutic outcomes in a model of corneal neovascularization. STATEMENT OF SIGNIFICANCE: Improving the ability to penetrate tissue barriers and averting inactivation caused by surrounding environments, are the keys to broaden the application of protein drugs. By decorating hydrophobic amino acid, tyrosine (Y), on hexahistidine peptide, YHmA encapsulated protein drug Ava with high efficiency by co-assembly strategy. YHmA displayed promising ability to maintain bioactivity of Ava during encapsulation and delivery, and protected Ava from proteinase K hydrolysis. Importantly, YHmA transferred Ava across the corneal epithelial barrier and greatly improved its bioavailability, producing surprisingly good therapeutic outcomes in a model of corneal neovascularization. Our results contributed to not only the strategy to overcome shortcomings of protein drugs, but also suggestion on hydrophilicity as a nonnegligible factor in nanodrug penetration through biobarriers.

Virtual screening and activity evaluation of multitargeting inhibitors for idiopathic pulmonary fibrosis

Transforming growth factor β receptor (TGF-β1R) and receptor tyrosine kinases (RTKs), such as VEGFRs, PDGFRs and FGFRs are considered important therapeutic targets in blocking myofibroblast migration and activation of idiopathic pulmonary fibrosis (IPF). To screen and design innovative prodrug to simultaneously target these four classes of receptors, we proposed an approach based on network pharmacology combining virtual screening and machine learning activity prediction, followed by efficient in vitro and in vivo models to evaluate drug activity. We first constructed Collagen1A2-A549 cells with type I collagen as the main biomarker and evaluated the activity of compounds to inhibit collagen expression at the cellular level. The data from the first round of Collagen1A2-A549 cell screening were substituted into the machine learning model, and the model was optimized accordingly. As a result, the false positive rate of the model was reduced from 85.0% to 66.7%, and two prospective compounds, Z103080500 and Z104578368, were finally selected. Collagen levels were reduced effectively by both Z103080500 (67.88% reduction) and Z104578368 (69.54% reduction). Moreover, these two compounds showed low cellular cytotoxicity. Subsequently, the effect of Z103080500 and Z104578368 was evaluated in a bleomycin-induced C57BL/6 mouse IPF model. These results showed that 50 mg/kg Z103080500 and Z104578368 could effectively reduce the number of inflammatory cells and the expression level of α-SMA. Meanwhile, Z103080500 and Z104578368 reduced the expression of major markers and inflammatory factors of IPF, such as collagen, IFN-γ, IL-17 and HYP, indicating that these screened Z103080500 and Z104578368 effectively delayed lung tissue inflammation and had a potential therapeutic effect on IPF. Our findings demonstrate that a screening and evaluation model for prodrug against IPF has been successfully established. It is of great significance to further modify these compounds to enhance their potency and activity.

Targeting Growth Factor and Cytokine Pathways to Treat Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease of unknown origin that usually results in death from secondary respiratory failure within 2–5 years of diagnosis. Recent studies have identified key roles of cytokine and growth factor pathways in the pathogenesis of IPF. Although there have been numerous clinical trials of drugs investigating their efficacy in the treatment of IPF, only Pirfenidone and Nintedanib have been approved by the FDA. However, they have some major limitations, such as insufficient efficacy, undesired side effects and poor pharmacokinetic properties. To give more insights into the discovery of potential targets for the treatment of IPF, this review provides an overview of cytokines, growth factors and their signaling pathways in IPF, which have important implications for fully exploiting the therapeutic potential of targeting cytokine and growth factor pathways. Advances in the field of cytokine and growth factor pathways will help slow disease progression, prolong life, and improve the quality of life for IPF patients in the future.

Molecular Mechanisms and Cellular Contribution from Lung Fibrosis to Lung Cancer Development

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung disease (ILD) of unknown aetiology, with a median survival of 2-4 years from the time of diagnosis. Although IPF has unknown aetiology by definition, there have been identified several risks factors increasing the probability of the onset and progression of the disease in IPF patients such as cigarette smoking and environmental risk factors associated with domestic and occupational exposure. Among them, cigarette smoking together with concomitant emphysema might predispose IPF patients to lung cancer (LC), mostly to non-small cell lung cancer (NSCLC), increasing the risk of lung cancer development. To this purpose, IPF and LC share several cellular and molecular processes driving the progression of both pathologies such as fibroblast transition proliferation and activation, endoplasmic reticulum stress, oxidative stress, and many genetic and epigenetic markers that predispose IPF patients to LC development. Nintedanib, a tyrosine-kinase inhibitor, was firstly developed as an anticancer drug and then recognized as an anti-fibrotic agent based on the common target molecular pathway. In this review our aim is to describe the updated studies on common cellular and molecular mechanisms between IPF and lung cancer, knowledge of which might help to find novel therapeutic targets for this disease combination.