Syndecan-2 Attenuates Radiation-induced Pulmonary Fibrosis and Inhibits Fibroblast Activation by Regulating PI3K/Akt/ROCK Pathway via CD148

A mussel-inspired, antibacterial, antioxidant, injectable composite hydrogel for the sustain delivery of salvianolic acid B for the treatment of frozen shoulder

Frozen shoulder (FS) manifests as progressively worsening pain and a reduction in shoulder range of motion (ROM). Salvianolic acid B (SaB) is recently expected to be used in the treatment of fibrosis diseases including FS. We firstly demonstrate that SaB can effectively hinder the progression of oxidative stress, inflammation, and pathological fibrosis within the synovial tissue in FS, potentially leading to the reduction or reversal of capsule fibrosis and joint stiffness. For further clinical application, we design and synthesize a novel, superior, antioxidant and antibacterial CSMA-PBA/OD-DA (CPDA) hydrogel for the delivery of SaB. In vitro experiments demonstrate that the CPDA hydrogel exhibits excellent biocompatibility and rheological properties, rendering it suitable for intra-articular injections. Upon injection into the contracted joint cavity of FS model rat, the SaB-CPDA hydrogel accelerate the recovery of ROM and exhibit superior anti-fibrosis effect, presenting the promise for the treatment of FS in vivo.

Cardiovascular toxicity in antitumor therapy: biological and therapeutic insights

The evolution of antitumor therapies has significantly improved cancer prognosis but has concurrently resulted in cardiovascular toxicities. Understanding the biological mechanisms behind these toxicities is crucial for effective management. Immunotherapy-related cardiovascular toxicities are primarily mediated by immune cells and secreted cytokines. Chemotherapy may cause cardiovascular damage through autophagy disruption and mitochondrial dysfunction. Targeted therapies can induce toxicity through endothelin-1 (ET-1) production and cardiac signaling disruption. Radiotherapy may lead to cardiomyopathy and myocardial fibrosis by affecting endothelial cells, triggering inflammatory responses and accelerating atherosclerosis. This review provides insights into these mechanisms and strategies, aiming to enhance the clinical prevention and treatment of cardiovascular toxicities.

Radiation-induced fibrosis: Mechanisms and therapeutic strategies from an immune microenvironment perspective

Radiation-induced fibrosis (RIF) is a severe chronic complication of radiotherapy (RT) manifested by excessive extracellular matrix (ECM) components deposition within the irradiated area. The lung, heart, skin, jaw, pelvic organs and so on may be affected by RIF, which hampers body functions and quality of life. There is accumulating evidence suggesting that the immune microenvironment may play a key regulatory role in RIF. This article discussed the synergetic or antagonistic effects of immune cells and mediators in regulating RIF's development. Several potential preventative and therapeutic strategies for RIF were proposed based on the immunological mechanisms to provide clinicians with improved cognition and clinical treatment guidance.

Multiomic analysis of monocyte-derived alveolar macrophages in idiopathic pulmonary fibrosis

BACKGROUND

Monocyte-derived alveolar macrophages (Mo_AMs) are increasingly recognised as potential pathogenic factors for idiopathic pulmonary fibrosis (IPF). While scRNAseq analysis has proven valuable in the transcriptome profiling of Mo_AMs, the integration analysis of multi-omics may provide additional dimensions of understanding of these cellular populations.

METHODS

We performed multi-omics analysis on 116 scRNAseq, 119 bulkseq and five scATACseq lung tissue samples from IPF. We built a large-scale IPF scRNAseq atlas and conducted the Monocle 2/3 as well as the Cellchat to explore the developmental path and intercellular communication on Mo_AMs. We also reported the difference in metabolisms, tissue repair and phagocytosis between Mo_AMs and tissue-resident alveolar macrophages (TRMs). To determine whether Mo_AMs affected pulmonary function, we projected clinical phenotypes (FVC%pred) from the bulkseq dataset onto the scRNAseq atlas. Finally, we used scATATCseq to uncover the upstream regulatory mechanisms and determine key drivers in Mo_AMs.

RESULTS

We identified three Mo_AMs clusters and the trajectory analysis further validated the origin of these clusters. Moreover, via the Cellchat analysis, the CXCL12/CXCR4 axis was found to be involved in the molecular basis of reciprocal interactions between Mo_AMs and fibroblasts through the activation of the ERK pathway in Mo_AMs. SPP1_RecMacs (RecMacs, recruited macrophages) were higher in the low-FVC group than in the high-FVC group. Specifically, compared with TRMs, the functions of lipid and energetic metabolism as well as tissue repair were higher in Mo_AMs than TRMs. But, TRMs may have higher level of phagocytosis than TRMs. SPIB (PU.1), JUNB, JUND, BACH2, FOSL2, and SMARCC1 showed stronger association with open chromatin of Mo_AMs than TRMs. Significant upregulated expression and deep chromatin accessibility of APOE were observed in both SPP1_RecMacs and TRMs.

CONCLUSION

Through trajectory analysis, it was confirmed that SPP1_RecMacs derived from Monocytes. Besides, Mo_AMs may influence FVC% pred and aggravate pulmonary fibrosis through the communication with fibroblasts. Furthermore, distinctive transcriptional regulators between Mo_AMs and TRMs implied that they may depend on different upstream regulatory mechanisms. Overall, this work provides a global overview of how Mo_AMs govern IPF and also helps determine better approaches and intervention therapies.

Pachymic Acid Protects Against Bleomycin-Induced Pulmonary Fibrosis by Suppressing Fibrotic, Inflammatory, and Oxidative Stress Pathways in Mice

Pachymic acid (PA), a natural extract from Poria cocos (Schw.) Wolf, possesses anti-inflammatory and anti-oxidative properties. However, it is still unknown whether PA can protect against bleomycin (BLM)-induced pulmonary fibrosis (PF). In this study, we investigated the effects of PA in mice administered BLM. Our results showed that PA significantly improved lung damage and pathological manifestations. Additionally, PA reduced the levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α, while increasing the level of IL-10. PA also decreased the levels of hydroxyproline and malondialdehyde, and increased the activities of superoxide dismutase and glutathione peroxidase in lung tissue. Furthermore, PA inhibited the increases in pyrin domain-containing protein 3 (NLRP3), ASC, IL-1β, P20, and TXNIP induced by BLM. In conclusion, our study demonstrated the protective effects of PA against BLM-induced PF in mice by suppressing fibrotic, inflammatory, and oxidative stress pathways.

DNA-PKcs/AKT1 inhibits epithelial-mesenchymal transition during radiation-induced pulmonary fibrosis by inducing ubiquitination and degradation of Twist1

INTRODUCTION

Radiation-induced pulmonary fibrosis (RIPF) is a chronic, progressive, irreversible lung interstitial disease that develops after radiotherapy. Although several previous studies have focused on the mechanism of epithelial-mesenchymal transition (EMT) in lung epithelial cells, the essential factors involved in this process remain poorly understood. The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) exhibits strong repair capacity when cells undergo radiation-induced damage; whether DNA-PKcs regulates EMT during RIPF remains unclear.

OBJECTIVES

To investigate the role and molecular mechanism of DNA-PKcs in RIPF and provide an important theoretical basis for utilising DNA-PKcs-targeted drugs for preventing RIPF.

METHODS

DNA-PKcs knockout (DPK-/-) mice were generated via the Cas9/sgRNA technique and subjected to whole chest ionizing radiation (IR) at a 20 Gy dose. Before whole chest IR, the mice were intragastrically administered the DNA-PKcs-targeted drug VND3207. Lung tissues were collected at 1 and 5 months after IR.

RESULTS

The expression of DNA-PKcs is low in pulmonary fibrosis (PF) patients. DNA-PKcs deficiency significantly exacerbated RIPF by promoting EMT in lung epithelial cells. Mechanistically, DNA-PKcs deletion by shRNA or inhibitor NU7441 maintained the protein stability of Twist1. Furthermore, AKT1 mediated the interaction between DNA-PKcs and Twist1. High Twist1 expression and EMT-associated changes caused by DNA-PKcs deletion were blocked by insulin-like growth factor-1 (IGF-1), an AKT1 agonist. The radioprotective drug VND3207 prevented IR-induced EMT and alleviated RIPF in mice by stimulating the kinase activity of DNA-PKcs.

CONCLUSION

Our study clarified the critical role and mechanism of DNA-PKcs in RIPF and showed that it could be a potential target for preventing RIPF.

Tissue fibrosis induced by radiotherapy: current understanding of the molecular mechanisms, diagnosis and therapeutic advances

Cancer remains the leading cause of death around the world. In cancer treatment, over 50% of cancer patients receive radiotherapy alone or in multimodal combinations with other therapies. One of the adverse consequences after radiation exposure is the occurrence of radiation-induced tissue fibrosis (RIF), which is characterized by the abnormal activation of myofibroblasts and the excessive accumulation of extracellular matrix. This phenotype can manifest in multiple organs, such as lung, skin, liver and kidney. In-depth studies on the mechanisms of radiation-induced fibrosis have shown that a variety of extracellular signals such as immune cells and abnormal release of cytokines, and intracellular signals such as cGAS/STING, oxidative stress response, metabolic reprogramming and proteasome pathway activation are involved in the activation of myofibroblasts. Tissue fibrosis is extremely harmful to patients' health and requires early diagnosis. In addition to traditional serum markers, histologic and imaging tests, the diagnostic potential of nuclear medicine techniques is emerging. Anti-inflammatory and antioxidant therapies are the traditional treatments for radiation-induced fibrosis. Recently, some promising therapeutic strategies have emerged, such as stem cell therapy and targeted therapies. However, incomplete knowledge of the mechanisms hinders the treatment of this disease. Here, we also highlight the potential mechanistic, diagnostic and therapeutic directions of radiation-induced fibrosis.

Salvianolic acid B attenuates inflammation and prevent pathologic fibrosis by inhibiting CD36-mediated activation of the PI3K-Akt signaling pathway in frozen shoulder

Frozen shoulder (FS) is characterized by pain and limited range of motion (ROM). Inflammation and fibrosis are accepted as main pathologic processes associated with the development of FS. However, the intrinsic mechanisms underlying pathologic fibrosis remain unclear. We aimed to elucidate the key molecules involved in pathologic fibrosis and explore new therapeutic targets for FS. Synovial fibroblasts isolated from patient biopsies were identified using immunofluorescence. Western blotting, RT-qPCR, cell adhesion tests, and would-healing assays were used to evaluate the fibrosis-related functions of synovial fibroblasts. Elevated cluster of differentiation 36 (CD36) expression was detected in FS using Western blotting and immunohistochemistry. Salvianolic acid b (SaB) inhibited CD36, blocking synovial fibroblast-induced inflammation and fibrosis. Our RNA-seq data showed that knocking down CD36 dramatically impaired the capacity of synovial fibroblasts for cell adhesion and that the PI3K-Akt signaling pathway may be crucial to the fibrotic process of FS. By up-regulating CD36 and inhibiting the phosphorylation of Akt, we demonstrated that CD36 promotes pathologic fibrosis by activating the PI3k-Akt pathway. Finally, rats treated with SaB had improved ROM and less collagen fiber deposition than the FS model group. Conclusion: SaB attenuates inflammation and inhibited the CD36-mediated activation of the PI3K-Akt signaling pathway to block pathologic fibrosis of FS in vitro and in vivo models.

Spatiotemporal Localisation of Heparan Sulphate Proteoglycans throughout Mouse Lens Morphogenesis

Heparan sulphate proteoglycans (HSPGs) consist of a core protein decorated with sulphated HS-glycosaminoglycan (GAG) chains. These negatively charged HS-GAG chains rely on the activity of PAPSS synthesising enzymes for their sulfation, which allows them to bind to and regulate the activity of many positively charged HS-binding proteins. HSPGs are found on the surfaces of cells and in the pericellular matrix, where they interact with various components of the cell microenvironment, including growth factors. By binding to and regulating ocular morphogens and growth factors, HSPGs are positioned to orchestrate growth factor-mediated signalling events that are essential for lens epithelial cell proliferation, migration, and lens fibre differentiation. Previous studies have shown that HS sulfation is essential for lens development. Moreover, each of the full-time HSPGs, differentiated by thirteen different core proteins, are differentially localised in a cell-type specific manner with regional differences in the postnatal rat lens. Here, the same thirteen HSPG-associated GAGs and core proteins as well as PAPSS2, are shown to be differentially regulated throughout murine lens development in a spatiotemporal manner. These findings suggest that HS-GAG sulfation is essential for growth factor-induced cellular processes during embryogenesis, and the unique and divergent localisation of different lens HSPG core proteins indicates that different HSPGs likely play specialized roles during lens induction and morphogenesis.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

The Novel Small Molecule BTB Inhibits Pro-Fibrotic Fibroblast Behavior though Inhibition of RhoA Activity

Idiopathic pulmonary fibrosis (IPF) is a progressive, chronic, interstitial lung disease with a poor prognosis. Although specific anti-fibrotic medications are now available, the median survival time following diagnosis remains very low, and new therapies are urgently needed. To uncover novel therapeutic targets, we examined how biochemical properties of the fibrotic lung are different from the healthy lung. Previous work identified lactate as a metabolite that is upregulated in IPF lung tissue. Importantly, inhibition of the enzyme responsible for lactate production prevents fibrosis in vivo. Further studies revealed that fibrotic lesions of the lung experience a significant decline in tissue pH, likely due to the overproduction of lactate. It is not entirely clear how cells in the lung respond to changes in extracellular pH, but a family of proton sensing G-protein coupled receptors has been shown to be activated by reductions in extracellular pH. This work examines the expression profiles of proton sensing GPCRs in non-fibrotic and IPF-derived primary human lung fibroblasts. We identify TDAG8 as a proton sensing GPCR that is upregulated in IPF fibroblasts and that knockdown of TDAG8 dampens myofibroblast differentiation. To our surprise, BTB, a proposed positive allosteric modulator of TDAG8, inhibits myofibroblast differentiation. Our data suggest that BTB does not require TDAG8 to inhibit myofibroblast differentiation, but rather inhibits myofibroblast differentiation through suppression of RhoA mediated signaling. Our work highlights the therapeutic potential of BTB as an anti-fibrotic treatment and expands upon the importance of RhoA-mediated signaling pathways in the context of myofibroblast differentiation. Furthermore, this works also suggests that TDAG8 inhibition may have therapeutic relevance in the treatment of IPF.

Fibrosis in frozen shoulder: Activation of IL-6 through PI3K-Akt signaling pathway in synovial fibroblast

Fibrosis is the main cause of limited range of motion (ROM) of shoulder in patients with frozen shoulder (FS). Overexpression of Interleukin 6 (IL-6) has been correlated with pathogenesis of FS. However, the underlying mechanism remains largely unexplored. In the current study, we focused on isolating synovial fibroblasts of FS and determining the influence of IL-6 as well as PI3K-Akt signaling pathway on the fibrotic process of synovial fibroblasts in FS by using RNA Sequencing (RNA-seq) and other molecular biology techniques. Synovial fibroblasts of FS express more extra cellular matrix (ECM) than that of control. RNA-seq results and bioinformatic analysis indicate that PI3K-Akt signaling pathway play an important role in the fibrotic process of FS, and IL-6 is the most related gene among those related to this process. The expression levels of IL-6 / IL-6R in FS synovial fibroblasts and IL-6 in culture supernatant were both significantly increased. siRNA interference with the expression of IL-6 attenuates the fibrosis level of FS as well as phosphorylation level of Akt. The findings suggest that synovial fibroblasts are key effector cells of fibrosis of FS. Activation of PI3K-Akt pathway can promote fibrosis of synovial fibroblasts in FS. IL-6 is up-regulated in synovial fibroblasts of FS and promoted the FS fibrosis through PI3K-Akt signaling pathway.

Network Pharmacology-Based Strategy to Identify the Pharmacological Mechanisms of Pulsatilla Decoction against Crohn's Disease

Purpose: To explore pharmacological mechanisms of Pulsatilla decoction (PD) against Crohn's disease (CD) via network pharmacology analysis followed by experimental validation. Methods: Public databases were searched to identify bioactive compounds and related targets of PD as well as related genes in patients with CD. Analyses using the drug-compound-target-disease network, the protein-protein interaction (PPI) network, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to predict the core targets and pathways of PD against CD. Colon tissue resected from patients with CD and tissue samples from a mouse model of CD fibrosis treated with PD were assessed to verify the major targets of PD in CD predicted by network pharmacologic analysis. Results: A search of the targets of bioactive compounds in PD and targets in CD identified 134 intersection targets. The target HSP90AA1, which was common to the drug-compound-target-disease and PPI networks, was used to simulate molecular docking with the corresponding bioactive compound. GO and KEGG enrichment analyses showed that multiple targets in the antifibrotic pathway were enriched and could be experimentally validated in CD patients and in a mouse model of CD fibrosis. Assays of colon tissues from CD patients showed that intestinal fibrosis was greater in stenoses than in nonstenoses, with upregulation of p-AKT, AKT, p-mTOR, mTOR, p-ERK1/2, ERK1/2, p-PKC, and PKC targets. Treatment of CD fibrosis mice with PD reduced the degree of fibrosis, with downregulation of the p-AKT, AKT, p-mTOR, mTOR, p-ERK1/2, ERK1/2, and PKC targets. Conclusion: Network pharmacology analysis was able to predict bioactive compounds in PD and their potential targets in CD. Several of these targets were validated experimentally, providing insight into the pharmacological mechanisms underlying the biological activities of PD in patients with CD.

Identifying Active Substances and the Pharmacological Mechanism of Houttuynia cordata Thunb. in Treating Radiation-Induced Lung Injury Based on Network Pharmacology and Molecular Docking Verification

Background

Houttuynia cordata Thunb. is a traditional Chinese herb widely used mainly because of the pharmacological effects related to heat clearance and detoxification. Emerging clinical evidence indicates that the efficacy of Houttuynia cordata Thunb. on RILI is upstanding. Nevertheless, its underlying therapeutic mechanism remains unclear and warrants further elucidation.

Methods

The major active components and corresponding targets of Houttuynia cordata Thunb. were retrieved from the traditional Chinese medicine system pharmacology database (TCMSP) and literature review. The related targets of RILI were retrieved from the GeneCards database. Common targets among the active compounds and diseases were identified through Venn diagram analysis. Cytoscape was employed to construct and visualize the network relationship among the drug, active compounds, targets, and disease. The protein interaction network (PPI) was constructed by STRING. The reliability (the binding affinity) of the core targets and active compounds was verified by molecular docking.

Results

A search of the TCMSP database and related literature revealed 12 active compounds of Houttuynia cordata Thunb. against RILI. The core active compounds included quercetin, kaempferol, hyperoside, and rutin. Hub nodes including TP53, VEGFA, JUN, TNF, and IL-6 were identified in the PPI network. The GO categories were classified into three functional categories: 112 biological processes, 9 molecular functions, and 32 cellular components of the active compounds of Houttuynia cordata Thunb. The KEGG pathway enrichment analysis demonstrated the enrichment of target genes in several key cancer-related signaling pathways, including the cancer pathways, TNF signaling pathway, PI3K-Akt signaling pathway, and HIF-1 signaling pathway. Molecular docking analysis validated the effective binding capacity of the main active compounds with the core targets.

Conclusion

The main active components of Houttuynia cordata Thunb. have a potential pharmacological effect against RILI via the cancer pathways, TNF signaling pathway, and PI3K-Akt signaling pathway.

The microRNA-cell surface proteoglycan axis in cancer progression

Proteoglycans consist one of the major extracellular matrix class of biomolecules that demonstrate nodal roles in cancer progression. Μodern diagnostic and therapeutic approaches include proteoglycan detection and pharmacological targeting in various cancers. Proteoglycans orchestrate critical signaling pathways for cancer development and progression through dynamic interactions with matrix components. It is well established that the epigenetic signatures of cancer cells play critical role in guiding their functional properties and metastatic potential. Secreted microRNAs (miRNAs) reside in a complex network with matrix proteoglycans, thus affecting cell-cell and cell-matrix communication. This mini-review aims to highlight current knowledge on the proteoglycan-mediated signaling cascades that regulate miRNA biogenesis in cancer. Moreover, the miRNA-mediated proteoglycan regulation during cancer progression and mechanistic aspects on the way that proteoglycans affect miRNA expression are presented. Recent advances on the role of cell surface proteoglycans in exosome biogenesis and miRNA packaging and expression are also discussed.

Syndecan-2 regulates PAD2 to exert antifibrotic effects on RA-ILD fibroblasts

Rheumatoid arthritis (RA)-associated interstitial lung disease (RA-ILD) is the most common pulmonary complication of RA, increasing morbidity and mortality. Anti-citrullinated protein antibodies have been associated with the development and progression of both RA and fibrotic lung disease; however, the role of protein citrullination in RA-ILD remains unclear. Here, we demonstrate that the expression of peptidylarginine deiminase 2 (PAD2), an enzyme that catalyzes protein citrullination, is increased in lung homogenates from subjects with RA-ILD and their lung fibroblasts. Chemical inhibition or genetic knockdown of PAD2 in RA-ILD fibroblasts attenuated their activation, marked by decreased myofibroblast differentiation, gel contraction, and extracellular matrix gene expression. Treatment of RA-ILD fibroblasts with the proteoglycan syndecan-2 (SDC2) yielded similar antifibrotic effects through regulation of PAD2 expression, phosphoinositide 3-kinase/Akt signaling, and Sp1 activation in a CD148-dependent manner. Furthermore, SDC2-transgenic mice exposed to bleomycin-induced lung injury in an inflammatory arthritis model expressed lower levels of PAD2 and were protected from the development of pulmonary fibrosis. Together, our results support a SDC2-sensitive profibrotic role for PAD2 in RA-ILD fibroblasts and identify PAD2 as a promising therapeutic target of RA-ILD.

Therapeutic effects of eperisone on pulmonary fibrosis via preferential suppression of fibroblast activity

Although the exact pathogenesis of idiopathic pulmonary fibrosis (IPF) is still unknown, the transdifferentiation of fibroblasts into myofibroblasts and the production of extracellular matrix components such as collagen, triggered by alveolar epithelial cell injury, are important mechanisms of IPF development. In the lungs of IPF patients, apoptosis is less likely to be induced in fibroblasts than in alveolar epithelial cells, and this process is involved in the pathogenesis of IPF. We used a library containing approved drugs to screen for drugs that preferentially reduce cell viability in LL29 cells (lung fibroblasts from an IPF patient) compared with A549 cells (human alveolar epithelial cell line). After screening, we selected eperisone, a central muscle relaxant used in clinical practice. Eperisone showed little toxicity in A549 cells and preferentially reduced the percentage of viable LL29 cells, while pirfenidone and nintedanib did not have this effect. Eperisone also significantly inhibited transforming growth factor-β1-dependent transdifferentiation of LL29 cells into myofibroblasts. In an in vivo study using ICR mice, eperisone inhibited bleomycin (BLM)-induced pulmonary fibrosis, respiratory dysfunction, and fibroblast activation. In contrast, pirfenidone and nintedanib were less effective than eperisone in inhibiting BLM-induced pulmonary fibrosis under this experimental condition. Finally, we showed that eperisone did not induce adverse effects in the liver and gastrointestinal tract in the BLM-induced pulmonary fibrosis model. Considering these results, we propose that eperisone may be safer and more therapeutically beneficial for IPF patients than current therapies.

Extracellular Matrix: Surface Proteoglycans

Cell surface proteoglycans, such as syndecans and glypicans, regulate molecular interactions that mediate cell adhesion, migration, proliferation, and differentiation. Through these activities, surface proteoglycans modulate critical biological processes of development, inflammation, infection, tissue repair, and cancer metastasis. Proteoglycans are unique glycoproteins comprised of one or several glycosaminoglycans attached covalently to core proteins. Glycosaminoglycans mediate the majority of ligand-binding functions of proteoglycans. Accumulating evidence indicates that surface proteoglycans regulate the onset, progression, and outcome of lung diseases, including lung injury, infection, fibrosis, and cancer. This article will review key features of surface proteoglycan biology in lung health and disease.

Explore the effects of pulmonary fibrosis on sperm quality and the role of the PI3K/Akt pathway based on rat model

Researches were reported that respiratory diseases can lead to male infertility; however, it is unclear whether there is a relationship between pulmonary fibrosis (PF) and male infertility. This study examined the influence of PF on sperm quality and its mechanisms. The key signalling pathway of male infertility caused by PF was predicted based on bioinformatics research. After modelling, we evaluated semen quality. Real-time quantitative polymerase chain reaction and Western blotting were used to measure the protein and mRNA expression levels of phosphatidylinositol 3-kinase (PI3K), phosphorylation-protein kinase B (p-Akt) and B-cell lymphoma 2 (Bcl2) in rat testicular cells. Compared with group A (48.77 ± 4.67; 59.77 ± 4.79), the sperm concentration and total sperm viability of group B (8.44 ± 1.71; 15.39 ± 3.48) showed a downward trend (p < 0.05). Western blotting showed that the protein expressions of PI3K, p-Akt and Bcl2 in the testes of group B (0.30 ± 0.06; 0.27 ± 0.05; 0.15 ± 0.03) was significantly lower than those of group A (0.71 ± 0.07; 0.72 ± 0.06; 0.50 ± 0.06) (p < 0.05). The hypoxic environment induced by PF can inhibit the expression of PI3K, p-Akt and Bcl2 protein and eventually cause dysfunctional spermatogenesis.

Sishen Pill Maintained Colonic Mucosal Barrier Integrity to Treat Ulcerative Colitis via Rho/ROCK Signaling Pathway

Sishen Pill (SSP) is a classical prescription of traditional Chinese medicine and often used to treat gastrointestinal diseases, including ulcerative colitis (UC). However, its mechanism is still unclear. We aimed to determine the mechanism of SSP in the treatment of UC by investigating if it maintains the integrity of the intestinal mucosal barrier via the Rho A/Rho kinase (ROCK) signaling pathway. Administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS) successfully induced chronic UC in rats, while the treatment effect of SSP was evaluated by body weight change, colonic length, colonic weight, colonic weight index, histological injury score, and pathological injury score after colitis rats were treated for 7 days. TNF-α and IL-1β levels were analyzed by ELISA, and the proteins of PI3K/Akt and RhoA/ROCK signaling pathway and junction proteins expression were measured by western blotting assay, and the distribution of Claudin 5 was shown by immunofluorescence. SSP significantly improved the clinical symptoms of colitis in rats and reduced the expression of p-RhoA, ROCK1, PI3K, and Akt in the colon mucosa, while it increased the expression of p-Rac and related proteins (Claudin-5, JAM1, VE-cadherin, and Connexin 43). In addition, SSP increased p-AMPKα and PTEN proteins expression, decreased Notch1 level, and hinted that activation of the PI3K/Akt signaling pathway was inhibited. In conclusion, SSP effectively treated chronic colitis induced by TNBS, which may have been achieved by inhibiting PI3K/Akt signal to suppress activation of the Rho/ROCK signaling pathway to finally maintain the integrity of the intestinal mucosal barrier.

5‑Aminosalicylic acid attenuates paraquat‑induced lung fibroblast activation and pulmonary fibrosis of rats

Pulmonary fibrosis is one of the most important pathological processes associated with paraquat (PQ) poisoning. 5‑Aminosalicylic acid (5‑ASA) has been shown to be a promising agent against fibrotic diseases. In the present study, the alleviating role of 5‑ASA was evaluated in a rat model of pulmonary fibrosis induced by PQ intragastric poisoning (80 mg/kg). Wistar rats were divided into control, PQ, 5‑ASA (30 mg/kg daily, 14 days) and PQ + 5‑ASA groups. Histological examination revealed congestion, edema and inflammatory cell infiltration in the bronchial and alveolar walls at 3 days after PQ exposure. Alveolar septum thickening with alveolar lumen narrowing was observed at 14 days, while fibroblast proliferation, increase in collagen fiber number and fibrous thickening of the alveolar walls were observed at 28 day. All the aforementioned pulmonary injury changes in the PQ group were attenuated in the PQ + 5‑ASA group. Hydroxyproline (HYP) content increased in the lung tissues of the rats at 14 days after PQ treatment and reached a peak at 28 days. Compared with the PQ group, HYP contents of lung tissue decreased at 14 and 28 days after PQ + 5‑ASA treatment. Masson's trichrome staining revealed that the increase in the amount of collagen fibers in the lung tissues of rats in the PQ group was inhibited by 5‑ASA treatment, further confirming the alleviating effect of 5‑ASA on fibrosis. In addition, the results showed that 5‑ASA attenuated the upregulation of transforming growth factor‑β1 and phosphorylated‑SMAD3, and the reduction of peroxisome proliferator activated receptor γ induced by PQ in lung tissue of rats and human lung fibroblast WI‑38 VA13 cells. In conclusion, the results suggested that 5‑ASA had an alleviating effect on PQ‑induced pulmonary fibrosis, partly by suppressing the activation of the TGF‑β1 signaling pathway.

The effects of CD148 Q276P/R326Q polymorphisms in A431D epidermoid cancer cell proliferation and epidermal growth factor receptor signaling

BACKGROUND

CD148 is a transmembrane protein tyrosine phosphatase that is expressed in multiple cell types. Previous studies have shown that CD148 dephosphorylates growth factor receptors and their signaling molecules, including EGFR and ERK1/2, and negatively regulates cancer cell growth. Furthermore, research of clinical patients has shown that highly linked CD148 gene polymorphisms, Gln276Pro (Q276P) and Arg326Gln (R326Q), are associated with an increased risk of several types of cancer. However, the biological effects of these missense mutations have not been studied.

AIM

We aimed to determine the biological effects of CD148 Q276P/R326Q mutations in cancer cell proliferation and growth factor signaling, with emphasis on EGFR signaling.

METHODS

CD148 forms, wild-type (WT) or Q276P/R326Q, were retrovirally introduced into A431D epidermoid carcinoma cells that lacks CD148 expression. The stable cells that express comparable levels of CD148 were sorted by flow cytometry. A431D cells infected with empty retrovirus was used as a control. CD148 localization, cell proliferation rate, EGFR signaling, and the response to thrombospondin-1 (TSP1), a CD148 ligand, were assessed by immunostaining, cell proliferation assay, enzyme-linked immunosorbent assay, and Western blotting.

RESULTS

Both CD148 forms (WT, Q276P/R326Q) were distributed to cell surface and all three cell lines expressed same level of EGFR. Compared to control cells, the A431D cells that express CD148 forms showed significantly lower cell proliferation rates. EGF-induced EGFR and ERK1/2 phosphorylation as well as cell proliferation were also significantly reduced in these cells. Furthermore, TSP1 inhibited cell proliferation in CD148 (WT, Q276P/R326Q)-expressing A431D cells, while it showed no effects in control cells. However, significant differences were not observed between CD148 WT and Q276P/R326Q cells.

CONCLUSION

Our data demonstrates that Q276P/R326Q mutations do not have major effects on TSP1-CD148 interaction as well as on CD148's cellular localization and activity to inhibit EGFR signaling and cell proliferation.

Mesenchymal stromal cell-derived syndecan-2 regulates the immune response during sepsis to foster bacterial clearance and resolution of inflammation

Sepsis is a life-threatening process related to a dysregulated host response to an underlying infection, which results in organ dysfunction and poor outcomes. Therapeutic strategies using mesenchymal stromal cells (MSCs) are under investigation for sepsis, with efforts to improve cellular utility. Syndecan (SDC) proteins are transmembrane proteoglycans involved with cellular signaling events including tissue repair and modulating inflammation. Bone marrow-derived human MSCs express syndecan-2 (SDC2) at a level higher than other SDC family members; thus, we explored SDC2 in MSC function. Administration of human MSCs silenced for SDC2 in experimental sepsis resulted in decreased bacterial clearance, and increased tissue injury and mortality compared with wild-type MSCs. These findings were associated with a loss of resolution of inflammation in the peritoneal cavity, and higher levels of proinflammatory mediators in organs. MSCs silenced for SDC2 had a decreased ability to promote phagocytosis of apoptotic neutrophils by macrophages in the peritoneum, and also a diminished capability to convert macrophages from a proinflammatory to a proresolution phenotype via cellular or paracrine actions. Extracellular vesicles are a paracrine effector of MSCs that may contribute to resolution of inflammation, and their production was dramatically reduced in SDC2-silenced human MSCs. Collectively, these data demonstrate the importance of SDC2 for cellular and paracrine function of human MSCs during sepsis.

CD148 Deficiency in Fibroblasts Promotes the Development of Pulmonary Fibrosis

Rationale: CD148/PTRJ (receptor-like protein tyrosine phosphatase η) exerts antifibrotic effects in experimental pulmonary fibrosis via interactions with its ligand syndecan-2; however, the role of CD148 in human pulmonary fibrosis remains incompletely characterized.Objectives: We investigated the role of CD148 in the profibrotic phenotype of fibroblasts in idiopathic pulmonary fibrosis (IPF).Methods: Conditional CD148 fibroblast-specific knockout mice were generated and exposed to bleomycin and then assessed for pulmonary fibrosis. Lung fibroblasts (mouse lung and human IPF lung), and precision-cut lung slices from human patients with IPF were isolated and subjected to experimental treatments. A CD148-activating 18-aa mimetic peptide (SDC2-pep) derived from syndecan-2 was evaluated for its therapeutic potential.Measurements and Main Results: CD148 expression was downregulated in IPF lungs and fibroblasts. In human IPF lung fibroblasts, silencing of CD148 increased extracellular matrix production and resistance to apoptosis, whereas overexpression of CD148 reversed the profibrotic phenotype. CD148 fibroblast-specific knockout mice displayed increased pulmonary fibrosis after bleomycin challenge compared with control mice. CD148-deficient fibroblasts exhibited hyperactivated PI3K/Akt/mTOR signaling, reduced autophagy, and increased p62 accumulation, which induced NF-κB activation and profibrotic gene expression. SDC2-pep reduced pulmonary fibrosis in vivo and inhibited IPF-derived fibroblast activation. In precision-cut lung slices from patients with IPF and control patients, SDC2-pep attenuated profibrotic gene expression in IPF and normal lungs stimulated with profibrotic stimuli.Conclusions: Lung fibroblast CD148 activation reduces p62 accumulation, which exerts antifibrotic effects by inhibiting NF-κB-mediated profibrotic gene expression. Targeting the CD148 phosphatase with activating ligands such as SDC2-pep may represent a potential therapeutic strategy in IPF.

Two Sides of the Coin: Mast Cells as a Key Regulator of Allergy and Acute/Chronic Inflammation

It is well known that mast cells (MCs) initiate type I allergic reactions and inflammation in a quick response to the various stimulants, including—but not limited to—allergens, pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs). MCs highly express receptors of these ligands and proteases (e.g., tryptase, chymase) and cytokines (TNF), and other granular components (e.g., histamine and serotonin) and aggravate the allergic reaction and inflammation. On the other hand, accumulated evidence has revealed that MCs also possess immune-regulatory functions, suppressing chronic inflammation and allergic reactions on some occasions. IL-2 and IL-10 released from MCs inhibit excessive immune responses. Recently, it has been revealed that allergen immunotherapy modulates the function of MCs from their allergic function to their regulatory function to suppress allergic reactions. This evidence suggests the possibility that manipulation of MCs functions will result in a novel approach to the treatment of various MCs-mediated diseases.

Syndecan receptors: pericellular regulators in development and inflammatory disease

The syndecans are the major family of transmembrane proteoglycans, usually bearing multiple heparan sulfate chains. They are present on virtually all nucleated cells of vertebrates and are also present in invertebrates, indicative of a long evolutionary history. Genetic models in both vertebrates and invertebrates have shown that syndecans link to the actin cytoskeleton and can fine-tune cell adhesion, migration, junction formation, polarity and differentiation. Although often associated as co-receptors with other classes of receptors (e.g. integrins, growth factor and morphogen receptors), syndecans can nonetheless signal to the cytoplasm in discrete ways. Syndecan expression levels are upregulated in development, tissue repair and an array of human diseases, which has led to the increased appreciation that they may be important in pathogenesis not only as diagnostic or prognostic agents, but also as potential targets. Here, their functions in development and inflammatory diseases are summarized, including their potential roles as conduits for viral pathogen entry into cells.

Mast Cell Tryptase Promotes Inflammatory Bowel Disease-Induced Intestinal Fibrosis

BACKGROUND

Intestinal fibrosis is the final pathological outcome of chronic intestinal inflammation without specific therapeutic drugs, which leads to ileus and surgical intervention. Intestinal fibrosis is characterized by excessive deposition of extracellular matrix (ECM). The role of mast cells (MCs), which are members of the sentinel immune cell population, is unknown in intestinal fibrosis.

METHODS

In this study, we analyzed changes in MCs, tryptase proteins, and ECM components in human fibrotic and control patient intestines. We constructed dextran sodium sulfate-induced intestinal fibrosis models using wild-type mice, MC-reconstituted mice, and MC-deficient mice to explore the role of MCs and tryptase in intestinal fibrosis. The roles and mechanisms of MCs and tryptase on fibroblasts were evaluated using human MCs (HMC-1 and LAD-2), commercial tryptase proteins, human colon fibroblasts (CCD-18Co fibroblasts), the tryptase inhibitor APC366, and the protease-activated receptor-2 (PAR-2) antagonist ENMD-1068.

RESULTS

Regardless of whether the colon was a human colon or a mouse colon, the fibrotic intestinal tissue had increased MC infiltration and a higher expression of ECM proteins or genes than that of the control group. The dextran sodium sulfate-induced intestinal fibrosis in MC-deficient mice was alleviated compared with that in wild-type mice. After MC reconstruction in MC-deficient mice, the alleviating effect disappeared. Tryptase, as a content stored in MC granules, was released into fibrotic intestinal tissues in the form of degranulation, resulting in an increased expression of tryptase. Compared with the control group, the tryptase inhibition group (the APC366 group) had reduced intestinal fibrosis. The CCD-18Co fibroblasts, when cocultured with MCs or treated with tryptase proteins, were activated to differentiate into myofibroblasts and secrete more ECM proteins (such as collagen and fibronectin). The underlying mechanism of fibroblast activation by tryptase was the activation of the PAR-2/Akt/mTOR pathway.

CONCLUSIONS

We found that MC tryptase promotes inflammatory bowel disease-induced intestinal fibrosis. The underlying mechanism is that tryptase promotes the differentiation of fibroblasts into fibrotic-phenotype myofibroblasts by activating the PAR-2/Akt/ mTOR pathway of fibroblasts.

Phlorotannins ameliorate extracellular matrix production in human vocal fold fibroblasts and prevent vocal fold fibrosis via aerosol inhalation in a laser-induced fibrosis model

Vocal fold fibrosis is an abnormal condition characterized by unfavorable changes in the organization of the extracellular matrix in vocal fold lamina propria. To prevent and treat vocal fold fibrosis, a number of synthetic drugs, such as mitomycin C and the glucocorticoid family, are used after surgery, but these are known to have some side effects. Therefore, using both in vitro and in vivo studies, this study investigated whether phlorotannins extracted from Ecklonia cava have the potential to prevent vocal fold fibrosis with minimal side effects. The results show that phlorotannins suppressed both the expression of the fibrotic phenotypic marker and cell migration by inhibiting the activation of the mitogen-activated protein kinase (MAPK) and Smad2/3 signaling pathways in human vocal fold fibroblasts stimulated by transforming growth factor-β. Additionally, phlorotannins exhibited antifibrotic efficacy without an excessive inflammatory response in a laser-induced fibrosis rabbit model when delivered as an aerosol via inhalation. Based on these results, phlorotannins should be considered a promising candidate for use in the prevention of vocal fold fibrosis.

The Cardiac Syndecan-2 Interactome

The extracellular matrix (ECM) is important in cardiac remodeling and syndecans have gained increased interest in this process due to their ability to convert changes in the ECM to cell signaling. In particular, syndecan-4 has been shown to be important for cardiac remodeling, whereas the role of its close relative syndecan-2 is largely unknown in the heart. To get more insight into the role of syndecan-2, we here sought to identify interaction partners of syndecan-2 in rat left ventricle. By using three different affinity purification methods combined with mass spectrometry (MS) analysis, we identified 30 novel partners and 9 partners previously described in the literature, which together make up the first cardiac syndecan-2 interactome. Eleven of the novel partners were also verified in HEK293 cells (i.e., AP2A2, CAVIN2, DDX19A, EIF4E, JPH2, MYL12A, NSF, PFDN2, PSMC5, PSMD11, and RRAD). The cardiac syndecan-2 interactome partners formed connections to each other and grouped into clusters mainly involved in cytoskeletal remodeling and protein metabolism, but also into a cluster consisting of a family of novel syndecan-2 interaction partners, the CAVINs. MS analyses revealed that although syndecan-2 was significantly enriched in fibroblast fractions, most of its partners were present in both cardiomyocytes and fibroblasts. Finally, a comparison of the cardiac syndecan-2 and -4 interactomes revealed surprisingly few protein partners in common.

Repeated radon exposure induced lung injury and epithelial-mesenchymal transition through the PI3K/AKT/mTOR pathway in human bronchial epithelial cells and mice

Radon exposure is the most frequent cause of lung cancer in non-smokers. The high linear energy transfer alpha-particles from radon decay cause the accumulation of multiple genetic changes and lead to cancer development. Epithelial-mesenchymal transition (EMT) plays an important role in oncogenesis. However, the mechanisms underlying chronic radon exposure-induced EMT attributed to carcinogenesis are not understood. This study aimed to explore the EMT and potential molecular mechanisms induced by repeated radon exposure. The EMT model of 16HBE and BEAS-2B cells was established with radon exposure (20000 Bq/m³, 20 min each time every 3 days). We found repeated radon exposure facilitated epithelial cell migration, proliferation, reduced cell adhesion and ability to undergo EMT through a decrease in epithelial markers and an increase in mesenchymal markers. Radon regulated the expression of matrix metalloproteinase 2 (MMP2) and tissue inhibitors of metalloproteinase 2 (TIMP2) to disrupt the balance of MMP2/TIMP2. In vivo, BALB/c mice were exposed to 10⁵ Bq/m³ radon gas for cumulative doses of 60 and 120 Working Level Months (WLM). Radon inhalation caused lung damage and fibrosis in mice, which was aggravated with the increase of exposure dose. EMT-like transformation also occurred in lung tissues of radon-exposure mice. Moreover, radon radiation increased p-PI3K, p-AKT and p-mTOR in cells and mice. Radon reduced the GSK-3β level and elevated the active β-catenin in 16HBE cells. The m-TOR and AKT inhibitors attenuated radon exposure-induced EMT by regulation related biomarkers. These data demonstrated that radon exposure induced EMT through the PI3K/AKT/mTOR pathway in epithelial cells and lung tissue.

Overexpression of microRNA-136-3p Alleviates Myocardial Injury in Coronary Artery Disease via the Rho A/ROCK Signaling Pathway

OBJECTIVE

Coronary artery disease (CAD) is a cardiovascular disease that poses a fatal threat to human health, and the identification of potential biomarkers may help to delineate its pathophysiological mechanisms. Accumulating evidence has implicated microRNAs (miRNAs) in the pathogenesis and development of cardiovascular diseases. The present study aims to identify the expression of miRNA-136-3p (miR-136-3p) in CAD and further investigate its functional relevance in myocardial injury both in vitro and in vivo.

METHODS

Initially, CAD models were induced in rats by high-fat diet and intraperitoneal injection of pituitrin. Next, the effect of overexpressed miR-136-3p on cardiac function and pathological damage in myocardial tissue, cardiomyocyte apoptosis, oxidative stress and inflammatory response were assessed in CAD rats. Rat cardiac microvascular endothelial cells (CMECs) were isolated and cultured by the tissue explant method, and the CMEC injury model was induced by homocysteine (HCY). The function of miR-136-3p in vitro was further evaluated.

RESULTS

miR-136-3p was poorly expressed in the myocardial tissue of CAD rats and CMEC injury models. In vivo assays indicated that overexpressed miR-136-3p could improve cardiac function and alleviate pathological damage in myocardial tissue, accompanied by reduced oxidative stress and inflammatory response. Moreover,in vitro assays suggested that overexpression of miR-136-3p enhanced proliferation and migration while inhibiting apoptosis of HCY-stressed CMECs. Notably, we revealed that EIF5A2 was a target gene of miR-136-3p, and miR-136-3p inhibited EIF5A2 expression and activation of the Rho A/ROCK signaling pathway.

CONCLUSION

In conclusion, the overexpression of miR-136-3p could potentially impede myocardial injury in vitro and in vivo in CAD through the blockade of the Rho A/ROCK signaling pathway, highlighting a potential miR-136-3p functional relevance in the treatment of CAD.

Targeting the renin-angiotensin-aldosterone system in fibrosis

Fibrosis is characterized by excessive deposition of extracellular matrix components such as collagen in tissues or organs. Fibrosis can develop in the heart, kidneys, liver, skin or any other body organ in response to injury or maladaptive reparative processes, reducing overall function and leading eventually to organ failure. A variety of cellular and molecular signaling mechanisms are involved in the pathogenesis of fibrosis. The renin-angiotensin-aldosterone system (RAAS) interacts with the potent Transforming Growth Factor β (TGFβ) pro-fibrotic pathway to mediate fibrosis in many cell and tissue types. RAAS consists of both classical and alternative pathways, which act to potentiate or antagonize fibrotic signaling mechanisms, respectively. This review provides an overview of recent literature describing the roles of RAAS in the pathogenesis of fibrosis, particularly in the liver, heart, kidney and skin, and with a focus on RAAS interactions with TGFβ signaling. Targeting RAAS to combat fibrosis represents a promising therapeutic approach, particularly given the lack of strategies for treating fibrosis as its own entity, thus animal and clinical studies to examine the impact of natural and synthetic substances to alter RAAS signaling as a means to treat fibrosis are reviewed as well.

Baicalin alleviates bleomycin‑induced pulmonary fibrosis and fibroblast proliferation in rats via the PI3K/AKT signaling pathway

Baicalin is an important flavonoid compound THAT is isolated from the Scutellaria baicalensis Georgi Chinese herb and plays a critical role in anti‑oxidative, anti‑inflammatory, anti‑infection and anti‑tumor functions. Although baicalin can suppress the proliferation of tumor cells, the underlying mechanisms of baicalin in bleomycin (BLM)‑induced pulmonary fibrosis remain to be elucidated. Thus, the aim of the present study was to determine the role of baicalin in pulmonary fibrosis and fibroblast proliferation in rats. Hematoxylin and eosin (H&E) and Masson staining were used to measure the morphology of pulmonary fibrosis, ELIASA kits were used to test the ROS and inflammation, and western blotting and TUNEL were performed to study the apoptosis proteins. In vitro, MTT assay, flow cytometry, western blotting and immunofluorescence were performed to investigate the effects of baicalin on proliferation of fibroblasts. The most significantly fibrotic changes were identified in the lungs of model rats at day 28. Baicalin (50 mg/kg) attenuated the degree of pulmonary fibrosis, and the hydroxyproline content of the lung tissues was decreased in the baicalin group, compared with the BLM group. Further investigation revealed that baicalin significantly increased glutathione peroxidase (GSH‑px), total‑superoxide dismutase (T‑SOD) and glutathione (GSH) levels, whilst decreasing that of serum malondialdehyde (MDA). TUNEL‑positive cells were significantly decreased in rats treated with baicalin group, compared with the model group. Furthermore, it was found that BLM promoted fibroblasts viability in a dose‑dependent manner in vivo, which was restricted following treatment with different concentrations of baicalin. Moreover, BLM promoted the expression levels of cyclin A, D and E, proliferating cell nuclear antigen, phosphorylated (p)‑AKT and p‑calcium/calmodulin‑dependent protein kinase type. BLM also promoted the transition of cells from the G0/G1 phase to the G2/M and S phases, and increased the intracellular Ca2+ concentration, which was subsequently suppressed by baicalin. Collectively, the results of the present study suggested that baicalin exerted a suppressive effect on BLM‑induced pulmonary fibrosis and fibroblast proliferation.

TGF-β in radiotherapy: Mechanisms of tumor resistance and normal tissues injury

Emerging evidences show that changes in tumor stroma can adapt cancer cells to radiotherapy, thereby leading to a reduction in tumor response to treatment. On the other hand, radiotherapy is associated with severe reactions in normal tissues which limit the amount radiation dose received by tumor. These challenges open a window in radiobiology and radiation oncology to explore mechanisms for improving tumor response and also alleviate side effects of radiotherapy. Transforming growth factor beta (TGF-β) is a well-known and multitasking cytokine that regulates a wide range of reactions and interactions within tumor and normal tissues. Within tumor microenvironment (TME), TGF-β is the most potent suppressor of immune system activity against cancer cells. This effect is mediated through stimulation of CD4+ which differentiates to T regulatory cells (Tregs), infiltration of fibroblasts and differentiation into cancer associated fibroblasts (CAFs), and also polarization of macrophages to M2 cells. These changes lead to suppression of cytotoxic CD8 + T lymphocytes (CTLs) and natural killer (NK) cells to kill cancer cells. TGF-β also plays a key role in the angiogenesis, invasion and DNA damage responses (DDR) in cancer cells. In normal tissues, TGF-β triggers the expression of a wide range of pro-oxidant and pro-fibrosis genes, leading to fibrosis, genomic instability and some other side effects. These properties of TGF-β make it a potential target to preserve normal tissues and sensitize tumor via its inhibition. In the current review, we aim to explain the mechanisms of upregulation of TGF-β and its consequences in both tumor and normal tissues.

Lung Adenocarcinoma Syndecan-2 Potentiates Cell Invasiveness

Altered expression of syndecan-2 (SDC2), a heparan sulfate proteoglycan, has been associated with diverse types of human cancers. However, the mechanisms by which SDC2 may contribute to the pathobiology of lung adenocarcinoma have not been previously explored. SDC2 levels were measured in human lung adenocarcinoma samples and lung cancer tissue microarrays using immunohistochemistry and real-time PCR. To understand the role of SDC2 in vitro, SDC2 was silenced or overexpressed in A549 lung adenocarcinoma cells. The invasive capacity of cells was assessed using Matrigel invasion assays and measuring matrix metalloproteinase (MMP) 9 expression. Finally, we assessed tumor growth and metastasis of SDC2-deficient A549 cells in a xenograft tumor model. SDC2 expression was upregulated in malignant epithelial cells and macrophages obtained from human lung adenocarcinomas. Silencing of SDC2 decreased MMP9 expression and attenuated the invasive capacity of A549 lung adenocarcinoma cells. The inhibitory effect of SDC2 silencing on MMP9 expression and cell invasion was reversed by overexpression of MMP9 and syntenin-1. SDC2 silencing attenuated NF-κB p65 subunit nuclear translocation and its binding to the MMP9 promoter, which were restored by overexpression of syntenin-1. SDC2 silencing in vivo reduced tumor mass volume and metastasis. These findings suggest that SDC2 plays an important role in the invasive properties of lung adenocarcinoma cells and that its effects are mediated by syntenin-1. Thus, inhibiting SDC2 expression or activity could serve as a potential therapeutic target to treat lung adenocarcinoma.

Potential Role of Integrin α₅β₁/Focal Adhesion Kinase (FAK) and Actin Cytoskeleton in the Mechanotransduction and Response of Human Gingival Fibroblasts Cultured on a 3-Dimension Lactide-Co-Glycolide (3D PLGA) Scaffold

BACKGROUND The stability of orthodontic treatment is thought to be significantly affected by the compression and retraction of gingival tissues, but the underlying molecular mechanism is not fully elucidated. The objectives of our study were to explore the effects of mechanical force on the ECM-integrin-cytoskeleton linkage response in human gingival fibroblasts (HGFs) cultured on 3-dimension (3D) lactide-co-glycolide (PLGA) biological scaffold and to further study the mechanotransduction pathways that could be involved. MATERIAL AND METHODS A compressive force of 25 g/m² was applied to the HGFs-PLGA 3D co-cultured model. Rhodamine-phalloidin staining was used to evaluate the filamentous actin (F-actin) cytoskeleton. The expression level of type I collagen (COL-1) and the activation of the integrin alpha₅ß₁/focal adhesion kinase (FAK) signaling pathway were determined by using real-time PCR and Western blotting analysis. The impacts of the applied force on the expression levels of FAK, phosphorylated focal adhesion kinase (p-FAK), and COL-1 were also measured in cells treated with integrin alpha₅ß₁ inhibitor (Ac-PHSCN-NH 2, ATN-161). RESULTS Mechanical force increased the expression of integrin alpha₅ß₁, FAK (p-FAK), and COL-1 in HGFs, and induced the formation of stress fibers. Blocking integrin alpha₅ß₁ reduced the expression of FAK (p-FAK), while the expression of COL-1 was not fully inhibited. CONCLUSIONS The integrin alpha₅ß₁/FAK signaling pathway and actin cytoskeleton appear to be involved in the mechanotransduction of HGFs. There could be other mechanisms involved in the promotion effect of mechanical force on collagen synthesis in addition to the integrin alpha₅ß₁ pathway.

Agonistic anti-CD148 monoclonal antibody attenuates diabetic nephropathy in mice

CD148 is a transmembrane protein tyrosine phosphatase (PTP) that is expressed in the renal vasculature, including the glomerulus. Previous studies have shown that CD148 plays a role in the negative regulation of growth factor signals (including epidermal growth factor and vascular endothelial growth factor), suppressing cell proliferation and transformation. However, the role of CD148 in kidney disease remains unknown. Here, we generated an agonistic anti-CD148 antibody and evaluated its effects in murine diabetic nephropathy (DN). Monoclonal antibodies (mAbs) against the mouse CD148 ectodomain sequence were generated by immunizing CD148 knockout (CD148KO) mice. The mAbs that increased CD148 activity were selected by biological (proliferation) and biochemical (PTP activity) assays. The mAb (18E1) that showed strong agonistic activity was injected (10 mg/kg ip) in streptozotocin-induced wild-type and CD148KO diabetic mice for 6 wk, and the renal phenotype was then assessed. The effects of 18E1 mAb in podocyte growth factor signals were also assessed in culture. Compared with control IgG, 18E1 mAb significantly decreased albuminuria and mesangial expansion without altering hyperglycemia and blood pressure in wild-type diabetic mice. Immunohistochemical evaluation showed that 18E1 mAb significantly prevented the reduction of podocyte number and nephrin expression and decreased glomerular fibronectin expression and renal macrophage infiltration. The 18E1 mAb showed no effects in CD148KO diabetic mice. Furthermore, we demonstrated that 18E1 mAb reduces podocyte epidermal growth factor receptor signals in culture and in diabetic mice. These findings suggest that agonistic anti-CD148 mAb attenuates DN in mice, in part by reducing epidermal growth factor receptor signals in podocytes. This antibody may be used for the treatment of early DN.

Idebenone has preventative and therapeutic effects on pulmonary fibrosis via preferential suppression of fibroblast activity

Alveolar epithelial injury induced by reactive oxygen species (ROS) and abnormal collagen production by activated fibroblasts (myofibroblasts) is involved in the onset and exacerbation of idiopathic pulmonary fibrosis (IPF). Compared with alveolar epithelial cells, lung fibroblasts, especially myofibroblasts, exhibit an apoptosis-resistance phenotype (apoptosis paradox) that appears to be involved in IPF pathogenesis. Thus, we screened for chemicals eliciting preferential cytotoxicity of LL29 cells (lung fibroblasts from an IPF patient) compared with A549 cells (human lung alveolar epithelial cell line) from medicines already in clinical use. We identified idebenone, a synthetic analogue of coenzyme Q10 (CoQ₁₀, an antioxidant) that has been used clinically as a brain metabolic stimulant. Idebenone induced cell growth inhibition and cell death in LL29 cells at a lower concentration than in A549 cells, a feature that was not observed for other antioxidant molecules (such as CoQ₁₀) and two IPF drugs (pirfenidone and nintedanib). Administration of idebenone prevented bleomycin-induced pulmonary fibrosis and increased pulmonary ROS levels. Importantly, idebenone also improved pulmonary fibrosis and lung function when administered after the development of fibrosis, whereas administration of CoQ₁₀ similarly prevented bleomycin-induced pulmonary fibrosis, but had no effect after its development. Administration of idebenone, but not CoQ₁₀, suppressed bleomycin-induced increases in lung myofibroblasts. In vitro, treatment of LL29 cells with idebenone, but not CoQ₁₀, suppressed TGF-β–induced collagen production. These results suggest that in addition to antioxidant activity, idebenone exerts inhibitory activity on the function of lung fibroblasts, with the former activity being preventative and the latter therapeutic for bleomycin-induced fibrosis. Thus, we propose that idebenone may be more therapeutically beneficial for IPF patients than current treatments.

Thrombin-cleaved syndecan-3/-4 ectodomain fragments mediate endothelial barrier dysfunction

Objective

The endothelial glycocalyx constitutes part of the endothelial barrier but its degradation leaves endothelial cells exposed to transmigrating cells and circulating mediators that can damage the barrier or promote intercellular gaps. Syndecan proteins are key components of the endothelial glycocalyx and are shed during disease states where expression and activity of proteases such as thrombin are elevated. We tested the ability of thrombin to cleave the ectodomains of syndecans and whether the products could act directly on endothelial cells to alter barrier function.

Approach and results

Using transmission electron microscopy, we illustrated the presence of glycocalyx in human lung microvasculature. We confirmed expression of all syndecan subtypes on the endothelial surface of agarose-inflated human lungs. ELISA and western blot analysis suggested that thrombin can cleave syndecan-3/-4 ectodomains to produce fragments. In vivo, syndecan-3 ectodomain fragments increased extravasation of albumin-bound Evans blue in mouse lung, indicative of plasma protein leakage into the surrounding tissue. Syndecan-3/-4 ectodomain fragments decreased transendothelial electrical resistance, a measure of cell-cell adhesive barrier integrity, in a manner sensitive to a Rho kinase inhibitor. These effects were independent of glycosylation and thrombin receptor PAR1. Moreover, these cleavage products caused rapid VE-cadherin-based adherens junction disorganization and increased F-actin stress fibers, supporting their direct effect on endothelial paracellular permeability.

Conclusions

We suggest that thrombin can cleave syndecan-3/4 ectodomain into fragments which interact with endothelial cells causing paracellular hyperpermeability. This may have important implications in the pathogenesis of vascular dysfunction during sepsis or thrombotic disease states where thrombin is activated.

Use of cholesterol and soluble tumour markers CEA and syndecan-2 in pleural effusions in cases of inconclusive cytology

Aims

In order to improve diagnostics in pleural effusions, additional value of effusion cholesterol, carcinoembryonic antigen (CEA) and syndecan-2 assays to cytology was studied.

Methods

Biomarkers were measured in effusion supernatants from 247 patients, of whom 126 had malignant pleural involvement, and their additional diagnostic efficacy to cytology was assessed.

Results

Syndecan-2 measurement, although gave detectable concentrations in all effusions with highest median value in mesotheliomas, was non-discriminative between different pathological conditions. CEA concentrations exceeding 5 ng/mL cut-off point indicated carcinomas, regardless of pleural involvement, which gave a sensitivity of 62% and specificity of 100% for carcinoma. Cholesterol concentration over 1.21 mmol/L cut-off value indicated neoplastic pleural involvement with 99% sensitivity and ‘merely’ 69% specificity, the latter mainly due to raised levels being associated also with benign inflammatory effusions. Combined CEA and cholesterol determinations increased the sensitivity for diagnosing carcinomatosis from 70% with cytology alone to 84% and established the correct diagnosis in 16 of 31 carcinomatosis cases with inconclusive cytology. Cholesterol measurement alone, with elevated level, in combination with absence of substantial number of inflammatory cells in effusion sediment proved to be a magnificent marker for neoplastic pleural involvement with 99% efficacy, and recognised all 36 such cases with inconclusive cytology.

Conclusions

Simultaneous measurement of CEA and cholesterol concentrations in effusion, or at least cholesterol alone, in combination with non-inflammatory fluid cytology, provides additional specific information about neoplastic pleural involvement, and can therefore be used as an adjunct to cytology, above all, in inconclusive cases.

Role of A2B adenosine receptor-dependent adenosine signaling in multi-walled carbon nanotube-triggered lung fibrosis in mice

Background

Multi-walled carbon nanotube (MWCNT)-induced lung fibrosis leads to health concerns in human. However, the mechanisms underlying fibrosis pathogenesis remains unclear. The adenosine (ADO) is produced in response to injury and serves a detrimental role in lung fibrosis. In this study, we aimed to explore the ADO signaling in the progression of lung fibrosis induced by MWCNT.

Results

MWCNT exposure markedly increased A_2B adenosine receptor (A_2BAR) expression in the lungs and ADO level in bronchoalveolar lavage fluid, combined with elevation of blood neutrophils, collagen fiber deposition, and activation of myeloperoxidase (MPO) activity in the lungs. Furthermore, MWCNT exposure elicited an activation of transforming growth factor (TGF)-β1 and follistatin-like 1 (Fstl1), leading to fibroblasts recruitment and differentiation into myofibroblasts in the lungs in an A_2BAR-dependent manner. Conversely, treatment of the selective A_2BAR antagonist CVT-6883 exhibited a significant reduction in levels of fibrosis mediators and efficiently decreased cytotoxicity and inflammatory in MWCNT treated mice.

Conclusion

Our results reveal that accumulation of extracellular ADO promotes the process of the fibroblast-to-myofibroblast transition via A_2BAR/TGF-β1/Fstl1 signaling in MWCNT-induced lung fibrosis.

Lanatoside C protects mice against bleomycin-induced pulmonary fibrosis through suppression of fibroblast proliferation and differentiation

It has been established that lanatoside C, a FDA-approved cardiac glycoside, reduces proliferation of cancer cell lines. The proliferation of fibroblasts is critical to the pathogenesis of pulmonary fibrosis (PF), a progressive and fatal fibrotic lung disease lacking effective treatment. In this study we have investigated the impact of lanatoside C on a bleomycin (BLM)-induced mouse model of PF and through the evaluation of fibroblast proliferation and activation in vitro. We evaluated explanted lung tissue by histological staining, western blot analysis, qRT-PCR and survival analysis, demonstrating that lanatoside C was able to protect mice against BLM-induced pulmonary fibrosis. The proliferation of cultured pulmonary fibroblasts isolated from BLM-induced PF mice was suppressed by lanatoside C, as hypothesized, through the induction of cell apoptosis and cell cycle arrest at the G2/M phase. The Akt signalling pathway was involved in this process. Interestingly, the production of α-SMA, fibronectin, and collagen I and III in response to TGF-β1 in healthy mouse fibroblasts was suppressed following lanatoside C administration by inhibition of TGF-β1/Smad signalling. In addition, TGF-β1-induced migration in lung fibroblasts was also impeded after lanatoside C treatment. Together, our data revealed that lanatoside C alleviated BLM-induced pulmonary fibrosis in mice via attenuation of growth and differentiation of fibroblasts, suggesting that it has potential as a candidate therapy for PF patients.

Ganoderma triterpenes Protect Against Hyperhomocysteinemia Induced Endothelial-Mesenchymal Transition via TGF-β Signaling Inhibition

Endothelial dysfunction is one of the most important pathological status in hyperhomocysteinemia (HHcy) related cardiovascular diseases. Whereas, the underlying mechanisms have not been fully elucidated yet, concomitant with the absence of effective treatment. The purpose of this study was to explore the main mechanisms involved in HHcy-induced endothelial injury and identify the protective effect of Ganoderma triterpenes (GT). Bovine aortic endothelial cells (BAECs) were applied as in vitro experimental model. The small molecular inhibitors were used to explore the signalings involved in HHcy-induced endothelial injury. The experimental results provided initial evidence that HHcy led to endothelial-mesenchymal transition (EndMT). Meanwhile, TGF-β/Smad, PI3K/AKT and MAPK pathways were activated in this process, which was demonstrated by pretreatment with TGF-β RI kinase inhibitor VI SB431542, PI3K inhibitor LY294002, p38 inhibitor SB203580, and ERK inhibitor PD98059. Furthermore, it was found that GT restrained the process of HHcy-induced EndMT via reducing oxidative stress and suppressing fore mentioned pathways with further inhibiting the activity of Snail. These results implicate that there is an untapped potential for GT as a novel therapeutic candidate for HHcy-induced EndMT through alleviating oxidative stress and canonical TGF-β/Smad and non-Smad dependent signaling pathways.

MiRNA-21 functions in ionizing radiation-induced epithelium-to-mesenchymal transition (EMT) by downregulating PTEN

Radiation-induced pulmonary fibrosis (RIPF) results from thoracic radiotherapy and severely limits the use of radiotherapy. Recent studies suggest that epithelium-to-mesenchymal transition (EMT) contributes to pulmonary fibrosis. Although miRNA dysregulation participates in a variety of pathophysiologic processes, their roles in fibrotic lung diseases and EMT are unclear. In this study, we aimed to identify key miRNAs involved in this process using a mouse model of RIPF previously established by irradiation with a single dose (20 Gy) of ⁶⁰Co γ-rays. At 2-weeks post-irradiation, a set of significantly upregulated miRNAs was identified in lung tissue by miRNA array analysis. This included miR-21, which has been reported to contribute to the pulmonary fibrotic response induced by stereotactic body radiotherapy. Here, we showed that miR-21 expression increased in parallel with EMT progression in the lungs of irradiated mice. Ectopic miR-21 expression promoted EMT progression in lung epithelial cells. Furthermore, downregulation of miR-21 expression by transfection of its inhibitor inhibited ionizing radiation (IR)-induced EMT. Knockdown of PTEN, which is the functional target of miR-21, reversed the attenuation of IR-induced EMT mediated by miR-21 downregulation. Radiation treatment decreased PTEN expression and increased Akt phosphorylation; these effects were abolished by the miR-21 inhibitor. MiR-21 overexpression in lung epithelial cell also downregulated PTEN expression and upregulated Akt phosphorylation. In conclusion, we have demonstrated that miR-21 functions as a key regulator of IR-induced EMT in lung epithelial cells via the PTEN/Akt pathway. Targeting miR-21 is implicated as a novel therapeutic strategy for the prevention of RIPF.

Tissue-informed engineering strategies for modeling human pulmonary diseases

Chronic pulmonary diseases, including idiopathic pulmonary fibrosis (IPF), pulmonary hypertension (PH), and chronic obstructive pulmonary disease (COPD), account for staggering morbidity and mortality worldwide but have limited clinical management options available. Although great progress has been made to elucidate the cellular and molecular pathways underlying these diseases, there remains a significant disparity between basic research endeavors and clinical outcomes. This discrepancy is due in part to the failure of many current disease models to recapitulate the dynamic changes that occur during pathogenesis in vivo. As a result, pulmonary medicine has recently experienced a rapid expansion in the application of engineering principles to characterize changes in human tissues in vivo and model the resulting pathogenic alterations in vitro. We envision that engineering strategies using precision biomaterials and advanced biomanufacturing will revolutionize current approaches to disease modeling and accelerate the development and validation of personalized therapies. This review highlights how advances in lung tissue characterization reveal dynamic changes in the structure, mechanics, and composition of the extracellular matrix in chronic pulmonary diseases and how this information paves the way for tissue-informed engineering of more organotypic models of human pathology. Current translational challenges are discussed as well as opportunities to overcome these barriers with precision biomaterial design and advanced biomanufacturing techniques that embody the principles of personalized medicine to facilitate the rapid development of novel therapeutics for this devastating group of chronic diseases.

Spotlight on the Transglutaminase 2-Heparan Sulfate Interaction

Heparan sulfate proteoglycans (HSPGs), syndecan-4 (Sdc4) especially, have been suggested as potential partners of transglutaminase-2 (TG2) in kidney and cardiac fibrosis, metastatic cancer, neurodegeneration and coeliac disease. The proposed role for HSPGs in the trafficking of TG2 at the cell surface and in the extracellular matrix (ECM) has been linked to the fibrogenic action of TG2 in experimental models of kidney fibrosis. As the TG2-HSPG interaction is largely mediated by the heparan sulfate (HS) chains of proteoglycans, in the past few years a number of studies have investigated the affinity of TG2 for HS, and the TG2 heparin binding site has been mapped with alternative outlooks. In this review, we aim to provide a compendium of the main literature available on the interaction of TG2 with HS, with reference to the pathological processes in which extracellular TG2 plays a role.

Advances in Molecular Mechanisms and Treatment of Radiation-Induced Pulmonary Fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a common complication in patients with lung cancer and breast cancer after receiving thoracic radiotherapy. The average incidence of RIPF is 16%-28% after radiotherapy. RIPF includes a heterogeneous group of lung disorders characterized by progressive and irreversible destruction of lung architecture and disruption of gas exchange. The clinical signs of RIPF include increasing dyspnea, deteriorating lung function, and accumulation of interstitial fluid, eventually leading to respiratory failure. No medical therapy for RIPF has been approved for routine clinical use despite the apparent need for an effective treatment. Numerous signaling pathways are involved in the initiation and progression of RIPF. Also, various approaches for RIPF treatments have focused on several aspects of the current understanding of the molecular pathology of RIPF. This review used the mechanistic categories of associated cell signaling pathways, epithelial cell dysfunction and senescence, abnormal lung remodeling, and aberrant innate and adaptive immunity to review the published literature on RIPF to date and then to identify potential areas for the effective treatment of RIPF.

Regulation of fibroblast Fas expression by soluble and mechanical pro-fibrotic stimuli

Background

Fibroblast apoptosis is a critical component of normal repair and the acquisition of an apoptosis-resistant phenotype contributes to the pathogenesis of fibrotic repair. Fibroblasts from fibrotic lungs of humans and mice demonstrate resistance to apoptosis induced by Fas-ligand and prior studies have shown that susceptibility to apoptosis is enhanced when Fas (CD95) expression is increased in these cells. Moreover, prior work shows that Fas expression in fibrotic lung fibroblasts is reduced by epigenetic silencing of the Fas promoter. However, the mechanisms by which microenvironmental stimuli such as TGF-β1 and substrate stiffness affect fibroblast Fas expression are not well understood.

Methods

Primary normal human lung fibroblasts (IMR-90) were cultured on tissue culture plastic or on polyacrylamide hydrogels with Young’s moduli to recapitulate the compliance of normal (400 Pa) or fibrotic (6400 Pa) lung tissue and treated with or without TGF-β1 (10 ng/mL) in the presence or absence of protein kinase inhibitors and/or inflammatory cytokines. Expression of Fas was assessed by quantitative real time RT-PCR, ELISA and Western blotting. Soluble Fas (sFas) was measured in conditioned media by ELISA. Apoptosis was assessed using the Cell Death Detection Kit and by Western blotting for cleaved PARP.

Results

Fas expression and susceptibility to apoptosis was diminished in fibroblasts cultured on 6400 Pa substrates compared to 400 Pa substrates. TGF-β1 reduced Fas mRNA and protein in a time- and dose-dependent manner dependent on focal adhesion kinase (FAK). Surprisingly, TGF-β1 did not significantly alter cell-surface Fas expression, but did stimulate secretion of sFas. Finally, enhanced Fas expression and increased susceptibility to apoptosis was induced by combined treatment with TNF-α/IFN-γ and was not inhibited by TGF-β1.

Conclusions

Soluble and matrix-mediated pro-fibrotic stimuli promote fibroblast resistance to apoptosis by decreasing Fas transcription while stimulating soluble Fas secretion. These findings suggest that distinct mechanisms regulating Fas expression in fibroblasts may serve different functions in the complex temporal and spatial evolution of normal and fibrotic wound-repair responses.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0801-4) contains supplementary material, which is available to authorized users.