Crosstalk between calpain activation and TGF-β1 augments collagen-I synthesis in pulmonary fibrosis

MSTN gene knockout suppresses the activation of lung fibroblasts through the inhibition of the Smad/AKT signaling pathway, thereby ameliorating pulmonary fibrosis

Pulmonary fibrosis is a chronic interstitial lung disease characterized by irreversible, progressive lung scarring and eventual respiratory failure. Fibroblast activation plays a crucial role in the progression of pulmonary fibrosis. Transforming growth factor-β (TGF-β) signaling contributes to pulmonary fibrosis by regulating lung fibroblast activation. Currently, most studies focus on TGF-β1 regulatory effects on fibroblasts, with limited reports on myostatin (MSTN), another member of the same family. This study used MSTN gene knockout (MSTN-/-) boars as animal models to explore MSTN regulatory effects on pulmonary fibrosis by modulating lung fibroblast activation. Studies have demonstrated that MSTN is significantly upregulated in the lungs during pulmonary fibrosis, promoting the activation of downstream Smad and AKT signaling pathways. MSTN-/- inhibits alveolar collapse and interstitial thickening in pulmonary fibrosis pigs and suppresses downstream Smad and AKT signaling. In vitro experiments showed that MSTN-/- inhibits lung fibroblast activation by blocking Smad/AKT signaling. These findings suggest that the MSTN/Smad/AKT signaling axis suppresses pulmonary fibrosis by inhibiting lung fibroblast activation, indicating that MSTN could be a potential therapeutic target for pulmonary fibrosis.

Pharmacological targeting of ECM homeostasis, fibroblast activation and invasion for the treatment of pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive interstitial lung disease with a dismal prognosis. While the standard-of-care (SOC) drugs approved for IPF represent a significant advancement in antifibrotic therapies, they primarily slow disease progression and have limited overall efficacy and many side effects. Consequently, IPF remains a condition with high unmet medical and pharmacological needs.

AREAS COVERED

A wide variety of molecules and mechanisms have been implicated in the pathogenesis of IPF, many of which have been targeted in clinical trials. In this review, we discuss the latest therapeutic targets that affect extracellular matrix (ECM) homeostasis and the activation of lung fibroblasts, with a specific focus on ECM invasion.

EXPERT OPINION

A promising new approach involves targeting ECM invasion by fibroblasts, a process that parallels cancer cell behavior. Several cancer drugs are now being tested in IPF for their ability to inhibit ECM invasion, offering significant potential for future treatments. The delivery of these therapies by inhalation is a promising development, as it may enhance local effectiveness and minimize systemic side effects, thereby improving patient safety and treatment efficacy.

Calpain-1 Up-Regulation Promotes Bleomycin-Induced Pulmonary Fibrosis by Activating Ferroptosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fatal disease. Calpain-1 is an effective therapeutic target for vascular endothelial dysfunction and pulmonary hypertension. However, the role of calpain-1 in bleomycin (BLM)-induced IPF has not been defined. The aim of this study was to assess the targeting of calpain-1 by activating ferroptosis in BLM-treated knockout mice and murine lung epithelial-12 cells. The role of calpain-1 in the regulation of IPF was investigated using a BLM-induced IPF mouse model. The results of this study showed that increased expression of calpain-1 was accompanied by increased fibrosis, lipid peroxidation, iron ion accumulation, and Yes-associated protein (YAP) levels and decreased levels of phosphorylated adenosine 5'-monophosphate-activated protein kinase (p-AMPK) in BLM-induced IPF. MDL-28170 (calpain-1 inhibition) treatment and calpain-1 knockdown alleviated ferroptosis and IPF induced by BLM. Overexpression of calpain-1 in murine lung epithelial-12 cells further exacerbated iron accumulation and IPF. Mechanistically, lentivirus-mediated up-regulation of calpain-1 inhibited AMPK activity and promoted the nuclear translocation of YAP, leading to high levels of acyl-CoA synthetase long-chain family 4 and transferrin receptor protein 1 and triggering a ferroptosis response that ultimately exacerbated BLM-induced lung fibrosis. Calpain-1 inhibition reversed these results and ameliorated BLM-induced IPF. In conclusion, these findings suggest that the calpain-1-acyl-CoA synthetase long-chain family 4-transferrin receptor protein 1-ferroptosis-positive regulatory axis contributes to BLM-induced IPF, which indicates that calpain-1 has potential therapeutic value for the treatment of IPF.

Ginsenoside Rg1 alleviates vascular remodeling in hypoxia-induced pulmonary hypertension mice through the calpain-1/STAT3 signaling pathway

Background

Hypoxic pulmonary hypertension (HPH) is the main pathological change in vascular remodeling, a complex cardiopulmonary disease caused by hypoxia. Some research results have shown that ginsenoside Rg1 (Rg1) can improve vascular remodeling, but the effect and mechanism of Rg1 on hypoxia-induced pulmonary hypertension are not clear. The purpose of this study was to discuss the potential mechanism of action of Rg1 on HPH.

Methods

C57BL/6 mice, calpain-1 knockout mice and Pulmonary artery smooth muscle cells (PASMCs) were exposed to a low oxygen environment with or without different treatments. The effect of Rg1 and calpain-1 silencing on inflammation, fibrosis, proliferation and the protein expression levels of calpain-1, STAT3 and p-STAT3 were determined at the animal and cellular levels.

Results

At the mouse and cellular levels, hypoxia promotes inflammation, fibrosis, and cell proliferation, and the expression of calpain-1 and p-STAT3 is also increased. Ginsenoside Rg1 administration and calpain-1 knockdown, MDL-28170, and HY-13818 treatment showed protective effects on hypoxia-induced inflammation, fibrosis, and cell proliferation, which may be associated with the downregulation of calpain-1 and p-STAT3 expression in mice and cells. In addition, overexpression of calpain 1 increased p-STAT3 expression, accelerating the onset of inflammation, fibrosis and cell proliferation in hypoxic PASMCs.

Conclusion

Ginsenoside Rg1 may ameliorate hypoxia-induced pulmonary vascular remodeling by suppressing the calpain-1/STAT3 signaling pathway.

Testing of Anti-EMT, Anti-Inflammatory and Antibacterial Activities of 2',4'-Dimethoxychalcone

Chalcone (1,3-diaryl-2-propen-1-one) is an α, β-unsaturated ketone that serves as an active constituent or precursor of numerous natural substances, exhibiting a broad spectrum of pharmacological effects. In this study, the classical Claisen-Schmidt condensation method was used to synthesize the chalcone derivative 2',4'-dimethoxychalcone (DTC) and evaluate its pharmacological activity. By upregulating the expression of the epithelial cell marker E-cadherin and downregulating the expression of the mesenchymal cell marker vimentin, DTC was found to inhibit transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) process in A549 cells, maintaining the cells' epithelial-like morphology and reducing the ability of the cells to migrate. Additionally, DTC demonstrated the ability to decrease the expression levels of nitric oxide (NO), tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) in RAW264.7 cells, suggesting a possible anti-inflammatory effect. Furthermore, DTC was found to exhibit bacteriostatic activity against Staphylococcus aureus (S. aureus), Proteus vulgaris (P. vulgaris), methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans (C. albicans), indicating that this chemical may possess broad-spectrum antibacterial activity.

Potential molecular targets for intervention in pelvic organ prolapse

Pelvic organ prolapse (POP) is a concerning gynecological benign illness in middle-aged and senior women. Its etiology is complex, the incidence rate is high, symptoms are clinically subjective, and its influence tends to be polarized. At present, for those who need medical treatment, whether surgical or non-surgical, complications cannot be ignored, and treatment effect needs to be optimized. However, there is a lack of accurate molecular biological interventions for the prevention, diagnosis, progression delay, and treatment of POP. Here, we reviewed the current state of understanding of the molecular mechanisms and factors associated with POP etiology. These factors include cyclins, matrix metal peptidases/tissue inhibitors of metalloproteinases, microRNAs, homeobox A11, transforming growth factor β1, insulin-like growth factor 1, fibulin 5, lysyl oxidase-like 1, oxidative stress, inflammatory response, estrogen, and other potential biomarkers associated with POP. In addition, relevant molecular targets that may be used to intervene in POP are summarized. The aim of this review was to provide more information to identify accurate potential biomarkers and/or molecular targets for the prevention, diagnosis, progression delay, and treatment of POP, with the goal of improving medical treatment for patients at-risk for POP or having POP. Continued research is needed to identify additional details of currently accepted molecular mechanisms and to identify additional mechanisms that contribute to POP.

A cysteine proteinase inhibitor ALLN alleviates bleomycin-induced skin and lung fibrosis

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disease that is characterized by fibrosis in the skin and internal organs, such as the lungs. Activated differentiation of progenitor cells, which are mainly resident fibroblasts, into myofibroblasts is considered a key mechanism underlying the overproduction of extracellular matrix and the resultant tissue fibrosis in SSc. Calpains are members of the Ca2+-dependent cysteine protease family, whose enzymatic activities participate in signal transduction and tissue remodeling, potentially contributing to fibrosis in various organs. However, the roles of calpain in the pathogenesis of SSc remain unknown. This study aimed to examine the anti-fibrotic properties of N-acetyl-Leu-Leu-norleucinal (ALLN), one of the cysteine proteinase inhibitors that primarily inhibit calpain, in vitro and in vivo, to optimally translate into the therapeutic utility in human SSc.

METHODS

Normal human dermal and lung fibroblasts pretreated with ALLN were stimulated with recombinant transforming growth factor beta 1 (TGF-β1), followed by assessment of TGF-β1/Smad signaling and fibrogenic molecules.

RESULTS

ALLN treatment significantly inhibited TGF-β1-induced phosphorylation and nuclear transport of Smad2/3 in skin and lung fibroblasts. TGF-β1-dependent increases in α-smooth muscle actin (αSMA), collagen type I, fibronectin 1, and some mesenchymal transcription markers were attenuated by ALLN. Moreover, our findings suggest that ALLN inhibits TGF-β1-induced mesenchymal transition in human lung epithelial cells. Consistent with these in vitro findings, administering ALLN (3 mg/kg/day) three times a week intraperitoneally remarkably suppressed the development of skin and lung fibrosis in a SSc mouse model induced by daily subcutaneous bleomycin injection. The number of skin- and lung-infiltrating CD3+ T cells decreased in ALLN-treated mice compared with that in control-treated mice. Phosphorylation of Smad3 and/or an increase in αSMA-positive myofibroblasts was significantly inhibited by ALLN treatment on the skin and lungs. However, no adverse effects were observed.

CONCLUSIONS

Our results prove that calpains can be a novel therapeutic target for skin and lung fibrosis in SSc, considering its inhibitor ALLN.

Qilongtian ameliorate bleomycin-induced pulmonary fibrosis in mice via inhibiting IL-17 signal pathway

Pulmonary fibrosis (PF) is a special type of pulmonary parenchymal disease, with chronic, progressive, fibrosis, and high mortality. There is a lack of safe, effective, and affordable treatment methods. Qilongtian (QLT) is a traditional Chinese prescription that is composed of Panax notoginseng, Earthworm, and Rhodiola, and shows the remarkable clinical curative effect of PF. However, the mechanism of QLT remains to be clarified. Therefore, we studied the effectivity of QLT in treating Bleomycin (BLM) induced PF mice. 36 C57BL/6 J mice were randomized into the control group, the model group, the low-, medium- and high-dose QLT group, and Pirfenidone group. After establishing a model of pulmonary fibrosis in mice, the control and model groups were infused with a normal saline solution, and the delivery group was infused with QLT. Pulmonary function in the mice from each group was detected. Pulmonary tissue morphologies and collagen deposition were stained by HE and Masson. The content of hydroxyproline (HYP) was detected by alkaline hydrolysis and the mRNA and protein expression of related genes in pulmonary tissues were detected by using q-PCR, ELISA, and Western blot. Our studies have shown that QLT significantly reduced the inflammatory injury, hydroxy-proline content, and collagen deposition of pulmonary tissue in BLM-induced PF mice and down-regulated the cytokine related to inflammation and fibrosis and PF expression on the mRNA and protein level in PF mice. To identify the mechanism of QLT, the Transcriptome was measured and the IL-17 signal pathway was screened out for further research. Further studies indicated that QLT reduced the mRNAs and protein levels of interleukin 17 (IL-17), c-c motif chemokine ligand 12 (CCL12), c-x-c motif chemokine ligand 5 (CXCL5), fos-like antigen 1 (FOSL1), matrix metalloproteinase-9 (MMP9), and amphiregulin (AREG), which are inflammation and fibrosis-related genes in the IL-17 signal pathway. The results indicated that the potential mechanism for QLT in the prevention of PF progression was by inhibiting inflammation resulting in the IL-17 signal pathway. Our study provides the novel scientific basis of QLT and represents new therapeutics for PF in clinical.

MIR99AHG inhibits EMT in pulmonary fibrosis via the miR-136-5p/USP4/ACE2 axis

Background

Long non-coding RNAs (lncRNAs) are closely related to the occurrence and development of cancer. Abnormally expressed lncRNA can be used as a diagnostic marker for cancer. In this study, we aim to investigate the clinical significance of MIR99AHG expression in lung adenocarcinoma (LUAD), and its biological roles in LUAD progression.

Methods

The relative expression of MIR99AHG in LUAD tissues and cell lines was analyzed using public databases and RT-qPCR. The biological functions of MIR99AHG were investigated using a loss-of-function approach. The effect of MIR99AHG on lung fibrosis was assessed by scratch assay, invasion assay and lung fibrosis rat model. FISH, luciferase reporter assay and immunofluorescence were performed to elucidate the underlying molecular mechanisms.

Results

LncRNA MIR99AHG expression level was downregulated in LUAD tissues and cell lines. Low MIR99AHG levels were associated with poorer patient overall survival. Functional analysis showed that MIR99AHG is associated with the LUAD malignant phenotype in vitro and in vivo. Further mechanistic studies showed that, MIR99AHG functions as a competitive endogenous RNA (ceRNA) to antagonize miR-136-5p-mediated ubiquitin specific protease 4 (USP4) degradation, thereby unregulated the expression of angiotensin-converting enzyme 2 (ACE2), a downstream target gene of USP4, which in turn affected alveolar type II epithelial cell fibrosis and epithelial–mesenchymal transition (EMT). In summary, the MIR99AHG/miR-136-5p/USP4/ACE2 signalling axis regulates lung fibrosis and EMT, thus inhibiting LUAD progression.

Conclusion

This study showed that downregulated MIR99AHG leads to the development of pulmonary fibrosis. Therefore, overexpression of MIR99AHG may provide a new approach to preventing LUAD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03633-y.

Expression of CD44, Transforming Growth Factor-β, and Matrix Metalloproteinases in Women With Pelvic Organ Prolapse

Background

Defects in the pelvic floor connective tissue may underlie the etiology of pelvic organ prolapse (POP). We hypothesized that the expression of proteins regulating extracellular matrix turnover is altered in the uterosacral ligament of women with POP. We compared the expression of CD44, transforming growth factor (TGF)-β, and matrix metalloproteinases (MMPs) 2/9 in women with and without POP.

Methods and Results

This matched case-control study included 30 postmenopausal women, with POP stage 2 and higher according to the POP quantification system, and 30 postmenopausal women without POP. Immunohistochemical analyses of the uterosacral ligament specimens obtained after hysterectomy were performed to determine CD44, TGF-β, MMP-2, and MMP-9 expression. The expression was quantified using ImageJ software, and the association between prolapse occurrence and risk factors was evaluated using Spearman's correlation analysis. CD44 expressions were significantly lower (p < 0.05), whereas MMP-2 and MMP-9 expression was higher (p < 0.0001 and p < 0.05, respectively), in the POP group than in the control group. The expression of TGF-β was similar in both groups. The occurrence of uterine prolapse was positively correlated with age, postmenopausal age, and MMP-2 and MMP-9 expression (p < 0.01) and negatively correlated with CD44 expression (p < 0.05).

Conclusion

CD44, MMP-2, and MMP-9 may play critical roles in the pathogenesis of POP and may be candidate biomarkers of POP progression.

Myeloid cell-specific deletion of Capns1 prevents macrophage polarization toward the M1 phenotype and reduces interstitial lung disease in the bleomycin model of systemic sclerosis

Background

Calpains are a family of calcium-dependent thiol proteases that participate in a wide variety of biological activities. In our recent study, calpain is increased in the sera of scleroderma or systemic sclerosis (SSc). However, the role of calpain in interstitial lung disease (ILD) has not been reported. ILD is a severe complication of SSc, which is the leading cause of death in SSc. The pathogenesis of SSc-related ILD remains incompletely understood. This study investigated the role of myeloid cell calpain in SSc-related ILD.

Methods

A novel line of mice with myeloid cell-specific deletion of Capns1 (Capns1-ko) was created. SSc-related ILD was induced in Capns1-ko mice and their wild-type littermates by injection 0.l mL of bleomycin (0.4 mg/mL) for 4 weeks. In a separate experiment, a pharmacological inhibitor of calpain PD150606 (Biomol, USA, 3 mg/kg/day, i.p.) daily for 30 days was given to mice after bleomycin injection on daily basis. At the end of the experiment, the animals were killed, skin and lung tissues were collected for the following analysis. Inflammation, fibrosis and calpain activity and cytokines were assessed by histological examinations and ELISA, and immunohistochemical analyses, western blot analysis and Flow cytometry analysis.

Results

Calpain activities increased in SSc-mouse lungs. Both deletion of Capns1 and administration of PD150606 attenuated dermal sclerosis as evidenced by a reduction of skin thickness and reduced interstitial fibrosis and inflammation in bleomycin model of SSc mice. These effects of reduced calpain expression or activity were associated with prevention of macrophage polarization toward M1 phenotype and consequent reduced production of pro-inflammatory cytokines including TNF-α, IL-12 and IL-23 in lung tissues of Capns1-ko mice with bleomycin model of SSc. Furthermore, inhibition of calpain correlated with an increase in the protein levels of PI3K and phosphorylated AKT1 in lung tissues of the bleomycin model of SSc mice.

Conclusions

This study for the first time demonstrates that the role of myeloid cell calpain may be promotion of macrophage M1 polarization and pro-inflammatory responses related PI3K/AKT1 signaling. Thus, myeloid cell calpain may be a potential therapeutic target for bleomycin model of SSc-related ILD.

Calpains as mechanistic drivers and therapeutic targets for ocular disease

Ophthalmic neurodegenerative diseases encompass a wide array of molecular pathologies unified by calpain dysregulation. Calpains are calcium-dependent proteases that perpetuate cellular death and inflammation when hyperactivated. Calpain inhibition trials in other organs have faced pharmacological challenges, but the eye offers many advantages for the development and testing of targeted molecular therapeutics, including small molecules, peptides, engineered proteins, drug implants, and gene-based therapies. This review highlights structural mechanisms underlying calpain activation, distinct cellular expression patterns, and in vivo models that link calpain hyperactivity to human retinal and developmental disease. Optimizing therapeutic approaches for calpain-mediated eye diseases can help accelerate clinically feasible strategies for treating calpain dysregulation in other diseased tissues.

Calpain-1 mediates vascular remodelling and fibrosis via HIF-1α in hypoxia-induced pulmonary hypertension

Calpain‐1, a calcium‐activated neutral cysteine proteases, has been reported to be involved in the formation of pulmonary hypertension. HIF‐1α, an oxygen‐sensitive transcription factor, has been reported to activate genes involved in cell proliferation and extracellular matrix recombination. This study was designed to investigate the effect of calpain‐1 in hypoxic pulmonary hypertension (HPH) and to explore whether there is a relationship between calpain‐1 and HIF‐1α in this disease. In the hypoxia‐induced model of HPH, we found that hypoxia resulted in increased right ventricular systolic pressure, right ventricular hypertrophy, pulmonary vascular remodelling and collagen deposition in lung tissues of mice. The levels of calpain‐1 and HIF‐1α were up‐regulated in the lung tissues of hypoxia‐treated mice and pulmonary arterial smooth muscle cells (PASMCs). Knock‐out of calpain‐1 restrained haemodynamic and histological changes induced by chronic hypoxia in mice, and inhibition of calpain‐1 also repressed the abnormal proliferation and migration of PASMCs. Besides, knock‐out or inhibition of calpain‐1 suppressed hypoxia‐induced expression of HIF‐1α, VEGF, PCNA, TGF‐β1, MMP2 and collagen I in vivo and in vitro. While inhibition of HIF‐1α abolished the above effects of calpain‐1. Furthermore, we found that calpain‐1 mediates the expression of HIF‐1α through NF‐κB (P65) under hypoxia conditions. In conclusion, our results suggest that calpain‐1 plays a pivotal role in hypoxia‐induced pulmonary vascular remodelling and fibrosis through HIF‐1α, providing a better understanding of the pathogenesis of HPH.

Calpain inhibition decreases myocardial fibrosis in chronically ischemic hypercholesterolemic swine

OBJECTIVES

Calpain activation during ischemia is known to play critical roles in myocardial remodeling. We hypothesize that calpain inhibition (CI) may serve to reverse and/or prevent fibrosis in chronically ischemic myocardium.

METHODS

Yorkshire swine were fed a high-cholesterol diet for 4 weeks followed by placement of an ameroid constrictor on the left circumflex artery to induce myocardial ischemia. 3 weeks later, animals received either: no drug; high-cholesterol control group (CON; n = 8); low-dose CI (0.12 mg/kg; LCI, n = 9); or high-dose CI (0.25 mg/kg; HCI, n = 8). The high-cholesterol diet and CI were continued for 5 weeks, after which myocardial tissue was harvested. Tissue samples were analyzed by western blot for changes in protein content.

RESULTS

In the setting of hypercholesterolemia and chronic myocardial ischemia, CI decreased the expression of collagen in ischemic and nonischemic myocardial tissue. This reduced collagen content was associated with a corresponding decrease in Jak/STAT/MCP-1 signaling pathway, suggesting a role for Jak 2 signaling in calpain activity. CI also decreases the expression of focal adhesion proteins (vinculin) and stabilizes the expression of cytoskeletal and structural proteins (N-cadherin, α-fodrin, desmin, vimentin, filamin, troponin-I). CI had no significant effect on metabolic and hemodynamic parameters.

CONCLUSIONS

Calpain inhibition may be a beneficial medical therapy to decrease collagen formation in patients with coronary artery disease and associated comorbidities.

Pleural mesothelial cell migration into lung parenchyma by calpain contributes to idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is defined as a specific form of chronic, progressive fibrosing interstitial pneumonia. It is unknown why fibrosis in IPF distributes in the peripheral or named sub-pleural area. Migration of pleural mesothelial cells (PMC) should contribute to sub-pleural fibrosis. Calpain is known to be involved in cell migration, but the role of calpain in PMC migration has not been investigated. In this study, we found that PMCs migrated into lung parenchyma in patients with IPF. Then using Wt1^{tm1(EGFP/Cre)Wtp} /J knock-in mice, we observed PMC migration into lung parenchyma in bleomycin-induced pleural fibrosis models, and calpain inhibitor attenuated pulmonary fibrosis with prevention of PMC migration. In vitro studies revealed that bleomycin and transforming growth factor-β1 increased calpain activity in PMCs, and activated calpain-mediated focal adhesion (FA) turnover as well as cell migration, cell proliferation, and collagen-I synthesis. Furthermore, we determined that calpain cleaved FA kinase in both C-terminal and N-terminal regions, which mediated FA turnover. Lastly, the data revealed that activated calpain was also involved in phosphorylation of cofilin-1, and p-cofilin-1 induced PMC migration. Taken together, this study provides evidence that calpain mediates PMC migration into lung parenchyma to promote sub-pleural fibrosis in IPF.

Calpastatin-Mediated Inhibition of Calpain Ameliorates Skin Scar Formation after Burn Injury

Hypertrophic scars, the most common complication of burn injuries, are characterized by excessive deposition of fibroblast-derived extracellular matrix proteins. Calpain, a calcium-dependent protease, is involved in the fibroblast proliferation and extracellular matrix production observed in certain fibrotic diseases. However, its role in the formation of post-burn hypertrophic skin scars remains largely unknown. Here, calpain expression and activity were assessed in skin fibroblasts obtained directly from patients with third-degree burns, who consequently developed post-burn hypertrophic scars. Furthermore, the antifibrotic effect of calpastatin, an endogenous calpain inhibitor, was evaluated in human fibroblasts and a murine burn model. The activity, mRNA levels, and protein levels of calpain were markedly higher in fibroblasts from the burn wounds of patients than in normal cells. Selective calpain inhibition by calpastatin markedly reduced not only the proliferation of burn-wound fibroblasts but also the mRNA and protein expression of calpain, transforming growth factor-beta 1, α-smooth muscle actin, type I and type III collagens, fibronectin, and vimentin in burn-wound fibroblasts. The anti-scarring effects of calpastatin were validated using a murine burn model by molecular, histological, and visual analyses. This study demonstrates the pathological role of calpain and the antifibrotic effect of calpastatin via calpain inhibition in post-burn hypertrophic scar formation.

VEGF/Src signaling mediated pleural barrier damage and increased permeability contributes to subpleural pulmonary fibrosis

The distribution of fibrosis in idiopathic pulmonary fibrosis (IPF) is subpleural with basal predominance. Alveolar epithelial cell was considered as the key cell in the initial phase of IPF. However, the idea of activation and damage of alveolar epithelial cells is very difficult to explain why fibrosis distributes in the subpleural area. In this study, human pleural mesothelial cell (PMC) line and primary rat PMC was used as in vitro model. Intraperitoneal injection of bleomycin was used for making a pulmonary fibrosis model. The integrity of cultured monolayer PMCs was determined by transepithelial electric resistance (TEER). Pleural permeability was estimated by measuring paracellular transport of fluorescein isothiocyanate (FITC)-conjugated dextran. Changes in lung tissue of patients with IPF were analyzed by Masson's and immunofluorescence staining. We found bleomycin induced PMCs damage and increased PMCs permeability; increased PMCs permeability aggravated bleomycin-induced subpleural inflammation and pulmonary fibrosis. Moreover, bleomycin was found to activate VEGF/Src signaling which increased PMCs permeability. In vivo, inhibition of VEGF/Src signaling prevented bleomycin-induced subpleural pulmonary fibrosis. At last, activation of VEGF/Src signaling was confirmed in subpleural area in patients with IPF. Taken together, our findings indicate that VEGF/Src signaling mediated pleural barrier damage and increased permeability which contributes to subpleural pulmonary fibrosis.

Pharmacological effects of indole alkaloids from Alstonia scholaris (L.) R. Br. on pulmonary fibrosis in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Alstonia scholaris (L.) R. Br. (Apocynaceae) is a Dai folk medicine for the treatment of lung diseases in China.

AIM OF THE STUDY

The present study investigated the anti-pulmonary fibrosis effects of total alkaloids (TA) and the potential active ingredients and its possible mechanism.

MATERIALS AND METHODS

After intratracheal instillation of bleomycin (BLM, 5 mg/kg), mice were divided into ten groups, and orally treated with the corresponding samples once daily for 28 days. The effect of indole alkaloids was determined through analysis of cytokines, as well as histopathological examinations and gene expressions.

RESULTS

Severe lung fibrosis was observed in the BLM-treated mice on day 28. However, the administration of TA significantly ameliorated the pathological changes in the lungs, decreased the content of Krebs von den Lungen-6, lactate dehydrogenase, transforming growth factor-β (TGF-β), hydroxyproline, type I collagen, and malonaldehyde, and enhanced the activity of superoxide dismutase in the serum and lung tissues. In addition, the enhanced TGF-β and matrix metalloproteinase-1 (MMP-1) expressions in BLM-induced mice were obviously weakened by indole alkaloids, as well as the ratio of matrix metalloproteinase-1 to tissue inhibitor of metalloproteinase-1 was decreased. Moreover, picrinine and scholaricine yielded markedly better values in the aforementioned indices than those in other samples, indicating that they may be the active ingredients of alkaloids.

CONCLUSIONS

TA exerted protective effects against BLM-induced pulmonary fibrosis by reducing collagen deposition through TGF-β/MMP-1 pathway.

Crosstalk between pleural mesothelial cell and lung fibroblast contributes to pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a specific form of chronic, progressive and fibrosing interstitial pneumonia of unknown cause. The main feature of IPF is a heterogeneous appearance with areas of sub-pleural fibrosis. However, the mechanism of sub-pleural fibrosis was poorly understood. In this study, our in vivo study revealed that pleural mesothelial cells (PMCs) migrated into lung parenchyma and localized alongside lung fibroblasts in sub-pleural area in mouse pulmonary fibrosis. Our in vitro study displayed that cultured-PMCs-medium induced lung fibroblasts transforming into myofibroblast, cultured-fibroblasts-medium promoted mesothelial-mesenchymal transition of PMCs. Furthermore, these changes in lung fibroblasts and PMCs were prevented by blocking TGF-β1/Smad2/3 signaling with SB431542. TGF-β1 neutralized antibody attenuated bleomycin-induced pulmonary fibrosis. Similar to TGF-β1/Smad2/3 signaling, wnt/β-catenin signaling was also activated in the process of PMCs crosstalk with lung fibroblasts. Moreover, inhibition of CD147 attenuated cultured-PMCs-medium induced collagen-I synthesis in lung fibroblasts. Blocking CD147 signaling also prevented bleomycin-induced pulmonary fibrosis. Our data indicated that crosstalk between PMC and lung fibroblast contributed to sub-pleural pulmonary fibrosis. TGF-β1, Wnt/β-catenin and CD147 signaling was involved in the underling mechanism.

Increased serum calpain activity is associated with HMGB1 levels in systemic sclerosis

Background

Systemic sclerosis (SSc) or scleroderma is an intractable autoimmune disorder that affects multiple organs. The objectives were to investigate clinical correlations of serum calpain activity and high mobility group box 1 (HMGB1) levels with immunological and clinical traits.

Methods

A total of 31 patients with SSc, 20 age- and gender-matched healthy control subjects (HC), and 10 patients with other connective tissue diseases (CTD) were recruited in the study. We measured serum calpain activity and HMGB1 levels and analyzed the datasets (GSE40839, GSE48149, GSE76808, GSE81292, GSE33463, and GSE58095) from Gene Expression Omnibus (GEO) database to explore the potential mechanism by which calpain exerts its function through bioinformatics methods.

Results

Serum calpain activity was significantly increased in patients with SSc compared with those in HC and in patients with CTD and was correlated with serum HMGB1 levels, modified Rodnan skin score, erythrocyte sedimentation rate, mean platelet volume, and plateletcrit. Notably, serum calpain activity and HMGB1 levels in SSc patients with interstitial lung disease (ILD) were significantly higher than those in SSc patients without ILD. Serum calpain activity and HMGB1 levels could be the independent risk factors for SSc-ILD and novel biomarkers in patients with SSc.

Conclusion

This is the first study that reports increased serum calpain activity and the correlation between calpain and HMGB1 in patients with SSc or SSc-ILD. The serum calpain activity and HMGB1 levels may serve as measures of ILD in patients with SSc. Also, calpain and HMGB1 could be potential therapeutic targets for patients with SSc or SSc-ILD in the future.

Triptolide protects against TGF-β1-induced pulmonary fibrosis by regulating FAK/calpain signaling

The present study aimed to investigate the mechanism of anti-proliferative, anti-inflammatory and anti-fibrotic effects of triptolide (TPL) on activated lung fibroblasts by regulating the focal adhesion kinase (FAK) and calpain signaling pathways. The HFL-1 human foetal lung fibroblast cell line was cultured in vitro and treated with 50 ng/ml transforming growth factor (TGF)-β1 for 48 h to establish the model of pulmonary fibrosis. Subsequently, the cells were divided into five groups, including a control, model, TPL, FAK inhibitor and calpeptin group. Subsequently, the proliferation of lung fibroblasts was detected using the Cell Counting Kit-8 assay. The concentration of interleukin (IL)-6 in the cell culture supernatant was examined by ELISA and the mRNA expression levels of collagen type I (ColI)α and ColIII in lung fibroblasts were quantified by reverse transcription-quantitative PCR. The protein levels of FAK, phosphorylated (p)-FAK, calpain 1 and calpain 2 were detected by western blot analysis. TGF-β1 induced the proliferation of lung fibroblasts, whereas TPL inhibited this proliferation in a dose-dependent manner. TPL also decreased the TGF-β1-induced production of IL-6 and reduced the upregulation of ColIα, ColIII, FAK, p-FAK, and inhibited the decrease of calpain 1 and calpain 2 induced by TGF-β1. In addition, the FAK inhibitor acted synergistically with TPL to decrease TGF-β1-induced production of IL-6 and attenuate TGF-β1-induced synthesis of ColIα and ColIII, while calpeptin had an antagonistic effect on the function of TPL. Furthermore, treatment with the FAK inhibitor and TPL markedly decreased the protein levels of FAK and p-FAK, and increased the protein expression of calpain 1 and calpain 2 in lung fibroblasts stimulated by TGF-β1 to a greater extent than TPL alone, while calpeptin had an antagonistic effect on the action of TPL. In conclusion, the present study indicated that TPL protected against TGF-β1-induced proliferation, inflammation and fibrosis by regulating the FAK and calpain signaling pathways.

Reactive Oxygen Species-Dependent Calpain Activation Contributes to Airway and Pulmonary Vascular Remodeling in Chronic Obstructive Pulmonary Disease

Aims: Airway and pulmonary vascular remodeling is an important pathological feature in the pathogenesis of chronic obstructive pulmonary disease (COPD). Tobacco smoke (TS) induces the production of large amounts of reactive oxygen species (ROS) in COPD lungs. We investigated how ROS lead to airway and pulmonary vascular remodeling in COPD. Results: We used in vitro bronchial and pulmonary artery smooth muscle cells (BSMCs and PASMCs), in vivo TS-induced COPD rodent models, and lung tissues of COPD patients. We found that H2O2 and TS extract (TSE) induced calpain activation in BSMCs and PASMCs. Calpain activation was elevated in smooth muscle of bronchi and pulmonary arterioles in COPD patients and TS-induced COPD rodent models. Calpain inhibition attenuated H2O2- and TSE-induced collagen synthesis and proliferation of BSMCs and PASMCs. Exposure to TS causes increases in airway resistance, right ventricular systolic pressure (RVSP), and thickening of bronchi and pulmonary arteries. Calpain inhibition by smooth muscle-specific knockout of calpain and the calpain inhibitor MDL28170 attenuated increases in airway resistance, RVSP, and thickening of bronchi and pulmonary arteries. Moreover, smooth muscle-specific knockout of calpain did not reduce TS-induced emphysema in the mouse model, but MDL28170 did reduce TS-induced emphysema in the rat model. Innovation: This study provides the first evidence that ROS-induced calpain activation contributes to airway and pulmonary vascular remodeling in TS-induced COPD. Calpain might be a novel therapeutic target for the treatment of COPD. Conclusion: These results indicate that ROS-induced calpain activation contributes to airway and pulmonary vascular remodeling and pulmonary hypertension in COPD.

Baicalein retards proliferation and collagen deposition by activating p38MAPK-JNK via microRNA-29

Immoderate proliferation and deposition of collagen generally result in hypertrophic scars and even keloids. microRNA-29 (miR-29) has been proved as a crucial regulator in these pathological processes. Although mounting evidence have proved baicalein (BAI) impairs scar formation, it is still incompletely understood whether miR-29 participated in the underlying mechanism. In the present study, NIH-3T3 cells were stimulated with BAI, and then cell viability was analyzed by cell counting kit-8 (CCK-8) and Western blot. We further analyzed total soluble collagen, collagen 1, and alpha-smooth muscle actin (α-SMA) in NIH-3T3 cells, which were exposed to transforming growth factor beta 1 (TGF-β1)/BAI, using a Sircol assay kit, quantitative reverse transcription-PCR (qRT-PCR) and Western blot, respectively. Besides, the miR-29 inhibitor was transduced and its transfection efficiency was verified by qRT-PCR. Finally, the phosphorylated p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) were examined by Western blot. BAI effectively retarded NIH-3T3 proliferation in a dose-dependent manner. Besides, TGF-β1-induced deposition of total soluble collagen and synthesis of collagen 1 and α-SMA were repressed by BAI at mRNA and protein levels. However, miR-29 inhibitor reversed the effects of BAI. Remarkably, BAI promoted phosphorylated expression of p38MAPK and JNK while miR-29 inhibitor reversed its effects on the phosphorylated expression of p38MAPK and JNK. BAI effectively weakened the cell viability and repressed TGF-β1-induced total soluble collagen as well as collagen 1 and α-SMA by upregulating miR-29. Mechanically, BAI activates the p38MAPK/JNK pathway by promoting miR-29.

In Vivo Monitoring of Calpain Activity by Forster Resonance Energy Transfer

Calpains are a 15-member class of calcium-activated nonlysosomal neutral proteases. They are involved in many cellular processes and are highly upregulated in pathological conditions. Some are ubiquitously expressed (CAPN1, CAPN2, CAPN4, CAPN5, CAPN7, and CAPN10), but others are thought to be localized in specific tissues. The monitoring of in vivo calpain activity is required for physiological, pathological, and therapeutic evaluations. This past decade, a tool for monitoring calpain activity in such conditions was developed using Forster resonance energy transfer (FRET). Studies showed that the level of calpain activity correlates with a decrease in FRET between the two fluorescent proteins. This chapter describes the methodologies from the design of the construct to the imaging procedure and analysis to evaluate ubiquitous calpain activity in vivo.

FRET-Based Assays to Determine Calpain Activity

Calpains are signaling proteases that have relatively little sequence specificity but some preferences for certain residues on either side of the scissile bond. As with most proteases, they mainly cut unstructured or extended regions of their target proteins. The tendency for concentrated calpain to rapidly autoproteolyze when activated by calcium complicates the kinetic assessment of calpain activity. As calpain autoproteolyzes, the amount of fully active enzyme continuously decreases until all of the calpain molecules have been cut and their activity reduced to a tiny fraction of the starting rate. To accurately measure calpain kinetics, only the initial rate of substrate hydrolysis, where autoproteolysis is minimal, can be used. To accomplish this, a method for rapid, quantifiable determination of substrate cleavage is required. Many of the existing assays are lacking in their sensitivity to accurately quantify calpain activity within this timeframe. However, the FRET peptide substrates developed by Cuerrier et al. have been shown to have sufficiently high affinity between substrate and enzyme to accurately measure the initial enzyme reaction velocity at substrate concentrations above the K_m value. With a suitably sensitive fluorimeter, sufficient data can be obtained to evaluate calpain kinetics and inhibition. Here we describe a facile, reliable calpain assay based on the continuous monitoring of FRET fluorescence from the highly sensitive calpain-specific substrate, (EDANS)-EPLFAERK-(DABCYL). We illustrate some difficulties associated with determining kinetic constants of whole calpains that are simultaneously undergoing autoproteolysis and how the assay can be used to help characterize calpain-specific inhibitors. We also present a variation of this fluorescence-based assay for high-throughput screening using the calpain protease core and a fluorescence plate reader.

Cigarette smoking aggravates bleomycin-induced experimental pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death. The cause of IPF is poorly understood. Although several environmental and occupational factors are considered as risk factors in IPF, cigarette smoking seems to be the most strongly associated risk factor. Here firstly, we treated mice with cigarette (16 mg tar, 1.0 mg nicotine in each cigarette) smoking and tried to explore the role of cigarette smoking in pulmonary fibrosis. Mice were continuously subjected to smoke for about 1 h each day (12 cigarettes per day, 5 days per week) during 40 days. Bleomycin was administrated by intraperitoneal injection at a dose of 40 mg/kg on days 1, 5, 8, 11 and 15. We found bleomycin induced pulmonary fibrosis in mice, and cigarette smoking augmented bleomycin-induced fibrosis reflected by both in fibrotic area and percentages of collagen in the lungs. Then we prepared and employed cigarette smoke extract (CSE) in cell models and found that CSE could induce the activation of p-Smad2/3 and p-Akt, as well as collagen-I synthesis and cell proliferation in lung fibroblasts and pleural mesothelial cells (PMCs). TGF-β1 signaling mediated CSE-induced PMCs migration. Moreover, in vitro studies revealed that CSE had superimposed effect on bleomycin-induced activation of TGF-β-Smad2/3 and -Akt signaling. TGF-β-Smad2/3 and -Akt signaling were further augmented by cigarette smoking in the lung of bleomycin-treated mice. Taken together, these findings represent the first evidence that cigarette smoking aggravated bleomycin-induced pulmonary fibrosis via TGF-β1 signaling.

The Influence of BuqiHuoxueTongluo Formula on Histopathology and Pulmonary Function Test in Bleomycin-Induced Idiopathic Pulmonary Fibrosis in Rats

BuqiHuoxueTongluo Formula (BHTF) is an effective herbal prescription based on traditional Chinese medicine for idiopathic pulmonary fibrosis (IPF). The aim of this study was to elucidate the influence of BHTF on induced IPF model through the aspect of histopathology and pulmonary function test. Wistar rats with bleomycin-induced IPF were given BHTF via intragastric gavage. After 14 days and 28 days of treatment, respectively, on these two time points, we first performed pulmonary function test, performed ventilation measure, and traced the Pressure-Volume Loop under anesthesia. Then, rats were sacrificed for hematoxylin-eosin and Masson's trichrome staining, immunohistochemistry staining of TGF-β1 and α-SMA, and observation through transmission electron microscope. BHTF reduced infiltration of inflammation cells, collagen deposition, and fibrosis proliferation in pulmonary mesenchyme, inhibited the expression of TGF-β1 and α-SMA, and avoided the abnormality of ultrastructure and quantities of lamellar bodies. It also ameliorated the parameters of FVC, MVV, PEF, FEF25, and Cdyn, maintained the shape of the Pressure-Volume Loop, and improved hysteresis. BHFT relieved the histopathologic changes, improved ventilation function, compliance, and work of breathing, meliorated the capacity and elasticity of the lungs, and stabilized the alveolar surface tension. Further speaking, it had a potential impact on the secretion of pulmonary surfactant.

Delayed, oral pharmacological inhibition of calpains attenuates adverse post-infarction remodelling

 

Calpains activate during myocardial ischemia-reperfusion and contribute to reperfusion injury. Studies in transgenic animals with altered calpain/calpastatin system subjected to permanent ischemia suggest that calpains are also involved in post-infarction remodelling and heart failure.

Aims

To determine whether delayed oral administration of the calpain inhibitor SNJ-1945 reduces adverse myocardial remodelling and dysfunction following transient coronary occlusion.

Methods and results

Male Sprague-Dawley rats were subjected to 30 min of ischemia followed by 21 days of reperfusion and received the calpain inhibitor SNJ-1945 intraperitoneally at the onset of reperfusion (Acute group), orally starting after 24 h of reperfusion and for 14 days (Chronic group), or the combination of both treatments. Calpain-1 and calpain-2 protein content increased and correlated with higher calpain activity in control hearts. Administration of SNJ-1945 attenuated calpain activation, and reduced scar expansion, ventricular dilation and dysfunction in both acute and chronic groups. Acute treatment reduced infarct size in hearts reperfused for 24 h and inflammation measured after 3 days. Delayed, chronic oral administration of SNJ-1945 attenuated inflammation, cardiomyocyte hypertrophy and collagen infiltration in the non-infarcted myocardium at 21 days in correlation with increased levels of IĸB and reduced NF-ĸB activation. In cultured fibroblasts, SNJ-1945 attenuated TGF-β1-induced fibroblast activation.

Conclusions

Our data demonstrate for the first time that long-term calpain inhibition is possible with delayed oral treatment, attenuates adverse post-infarction remodelling, likely through prevention of NF-ĸB activation, and may be a promising therapeutic intervention to prevent adverse remodelling and heart failure in patients with acute myocardial infarction.

The impaired proteases and anti-proteases balance in Idiopathic Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a devastating chronic, progressive and irreversible disease that remains refractory to current therapies. Matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of MMPs (TIMPs), have been implicated in the development of pulmonary fibrosis since decades. Coagulation signalling deregulation, which influences several key inflammatory and fibro-proliferative responses, is also essential in IPF pathogenesis, and a growing body of evidence indicates that Protease-Activated Receptors (PARs) inhibition in IPF may be promising for future evaluation. Therefore, proteases and anti-proteases aroused great biomedical interest over the past years, owing to the identification of their potential roles in lung fibrosis. During these last decades, numerous other proteases and anti-proteases have been studied in lung fibrosis, such as matriptase, Human airway trypsin-like protease (HAT), Hepatocyte growth factor activator (HGFA)/HGFA activator inhibitor (HAI) system, Plasminogen activator inhibitor (PAI)-1, Protease nexine (PN)-1, cathepsins, calpains, and cystatin C. Herein, we provide a general overview of the proteases and anti-proteases unbalance during lung fibrogenesis and explore potential therapeutics for IPF.

Matrine suppresses cardiac fibrosis by inhibiting the TGF‑β/Smad pathway in experimental diabetic cardiomyopathy

Cardiac fibrosis is one of the pathological characteristics of diabetic cardiomyopathy (DbCM). Matrine treatment has proven to be effective in cases of organ fibrosis and cardiovascular diseases. In the present study, the anti-fibrosis-associated cardioprotective effects of matrine on DbCM were investigated. Rats with experimental DbCM were administered matrine orally. Cardiac functions were evaluated using invasive hemodynamic examinations. Cardiac compliance was assessed in isolated hearts. Using Sirius Red and fluorescence staining, the collagen in diabetic hearts was visualized. MTT assay was used to select non-cytotoxic concentrations of matrine, which were subsequently used to treat isolated cardiac fibroblasts incubated under various conditions. Western blotting was performed to assess activation of the transforming growth factor-β1 (TGF-β1)/Smad signaling pathway. Rats with DbCM exhibited impaired heart compliance and left ventricular (LV) functions. Excessive collagen deposition in cardiac tissue was also observed. Furthermore, TGF-β1/R-Smad (Smad2/3) signaling was revealed to be markedly activated; however, the expression of inhibitory Smad (I-Smad, also termed Smad7) was reduced in DbCM. Matrine administration led to a marked recovery in LV function and heart compliance by exerting inhibitory effects on TGF-β1/R-Smad signaling pathway-induced fibrosis without affecting I-Smad. Incubation with a high concentration of glucose triggered the TGF-β1/R-Smad (Smad2/3) signaling pathway and suppressed I-Smad signaling transduction in cultured cardiac fibroblasts, which led to an increase in the synthesis of collagen. After cardiac fibroblasts had been treated with matrine at non-cytotoxic concentrations without affecting I-Smad, matrine blocked TGF-β1/R-Smad signaling transduction to repress collagen production and deposition. In conclusion, the results of the present study demonstrated that TGF-β1/Smad signaling-associated cardiac fibrosis is involved in the impairment of heart compliance and LV dysfunction in DbCM. By exerting therapeutic effects against cardiac fibrosis via its influence on TGF-β1/Smad signaling, matrine exhibited cardioprotective effects in DbCM.

Inhibition of angiotensin II and calpain attenuates pleural fibrosis

Pleural fibrosis is associated with various inflammatory processes such as tuberculous pleurisy and bacterial empyema. There is currently no ideal therapeutic to attenuate pleural fibrosis. Some pro-fibrogenic mediators induce fibrosis through inflammatory processes, suggesting that blockage of these mediators might prevent pleural fibrosis. The MeT-5A human pleural mesothelial cell line (PMC) was used in this study as an in vitro model of fibrosis; and intra-pleural injection of bleomycin with carbon particles was used as an in vivo mouse model of pleural fibrosis. Calpain knockout mice, calpain inhibitor (calpeptin), and angiotensin (Ang) II type 1 receptor (AT₁R) antagonist (losartan) were evaluated in prevention of experimental pleural fibrosis. We found that bleomycin and carbon particles induced calpain activation in cultured PMCs. This in vitro response was associated with increased collagen-I synthesis, and was blocked by calpain inhibitor or AT₁R antagonist. Calpain genetic or treatment with calpeptin or losartan prevented pleural fibrosis in a mouse model induced by bleomycin and carbon particles. Our findings indicate that Ang II signaling and calpain activation induce collagen-I synthesis and contribute to fibrotic alterations in pleural fibrosis. Inhibition of Ang II and calpain might therefore be a novel strategy in treatment of pleural fibrosis.

Upregulation of long noncoding RNA AP003419.16 predicts high risk of aging‑associated idiopathic pulmonary fibrosis

Long noncoding RNAs (lncRNAs) are able to regulate adjacent genes and thus participate in the incidence in the present study has identified lncRNA AP003419.16, adjacent to the protein-coding gene ribosomal protein S6 kinase B-2 (RPS6KB2). RPS6KB2 is believed to be involved in the process of aging and idiopathic pulmonary fibrosis (IPF), due to its activation by growth factors and regulation by the protein kinase mTOR signaling pathway. The results of the present study indicated that the expression of AP003419.16 increased significantly in patients with IPF, whereas its adjacent gene ribosomal protein S6 kinase B-2 increased simultaneously. AP003419.16 expression may be used to predict an increased risk of aging-associated IPF. The present study provided a molecular hypothesis of IPF occurrence in the aging process, in addition to novel molecular targets for the clinical treatment of IPF.

Matrine attenuates cardiac fibrosis by affecting ATF6 signaling pathway in diabetic cardiomyopathy

Cardiac function and compliance impairments are the features of cardiac fibrosis. Matrine shows therapeutic effects on cardiovascular diseases and organ fibrosis. In this study, we examined the therapeutic effects and mechanisms of matrine on cardiac fibrosis of DbCM. Matrine was administrated orally to rats with DbCM. Cardiac functions and compliance were evaluated. The collagen deposition was visualized by sirius red staining. Real-time PCR was used to determine the expression level of miRNA. Western blotting was performed to assess the protein expression. NFAT nuclear translocation was evaluated by fluorescent immunochemistry staining and Western blotting. Intracellular calcium level was assessed by fura-2/AM staining. A colorimetric method was used to determine calcineurin enzymatic activity. Impaired cardiac function and compliance were observed in rats with DbCM. Increased collagen deposition in cardiac tissue was found. Furthermore, ATF6 signaling was activated, leading to intracellular calcium accumulation and NFAT activation which further initiated ECM gene expressions. Matrine administration recovered cardiac function and improved compliance by exerting inhibitory effects against ATF6 signaling- induced fibrosis. The high- glucose incubation induced ATF6 signaling activation in cultured CFs to increase the synthesis of ECM. Matrine blocked the ATF6 signaling in CFs to inhibit ECM synthesis within non- cytotoxic concentrations. ATF6 signaling induced cardiac fibrosis was one of the mechanisms involved in DbCM, which was characterized by loss of cardiac compliance and functions. Matrine attenuated cardiac compliance and improved left ventricular functions by exerting therapeutic effects against cardiac fibrosis via affecting ATF6 signaling pathway.

miR-18a-5p Inhibits Sub-pleural Pulmonary Fibrosis by Targeting TGF-β Receptor II

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease that typically leads to respiratory failure and death within 3-5 years of diagnosis. Sub-pleural pulmonary fibrosis is a pathological hallmark of IPF. Bleomycin treatment of mice is a an established pulmonary fibrosis model. We recently showed that bleomycin-induced epithelial-mesenchymal transition (EMT) contributes to pleural mesothelial cell (PMC) migration and sub-pleural pulmonary fibrosis. MicroRNA (miRNA) expression has recently been implicated in the pathogenesis of IPF. However, changes in miRNA expression in PMCs and sub-pleural fibrosis have not been reported. Using cultured PMCs and a pulmonary fibrosis animal model, we found that miR-18a-5p was reduced in PMCs treated with bleomycin and that downregulation of miR-18a-5p contributed to EMT of PMCs. Furthermore, we determined that miR-18a-5p binds to the 3' UTR region of transforming growth factor β receptor II (TGF-βRII) mRNA, and this is associated with reduced TGF-βRII expression and suppression of TGF-β-Smad2/3 signaling. Overexpression of miR-18a-5p prevented bleomycin-induced EMT of PMC and inhibited bleomycin-induced sub-pleural fibrosis in mice. Taken together, our data indicate that downregulated miR-18a-5p mediates sub-pleural pulmonary fibrosis through upregulation of its target, TGF-βRII, and that overexpression of miR-18a-5p might therefore provide a novel approach to the treatment of IPF.

TRPC1-STIM1 activation modulates transforming growth factor β-induced epithelial-to-mesenchymal transition

Activation of Epithelial-to-Mesenchymal Transition (EMT) is important for tumor metastasis. Although growth factors such as TGFβ and EGF have been shown to induce EMT in breast epithelial cells, the mechanism resulting in migration is not well understood. Herein, we provide evidence that Ca2+ entry into the cell, especially upon store-depletion, plays an important role in TGFβ-induced EMT by promoting cellular migration and potentially leading to metastasis. The increased migration by TGFβ in non-cancerous cells was due to the loss of E-cadherin along with a subsequent increase in N-cadherin levels. Importantly, TGFβ-treatment increases store-mediated Ca2+ entry, which was essential for the activation of calpain leading to the loss of E-cadherin and MMP activation. Inhibition of Ca2+ entry by using Ca2+ channel blocker SKF-96365, significantly decreased Ca2+ entry, decreased TGFβ-induced calpain activation, and suppressed the loss of E-cadherin along with inhibiting cell migration. Furthermore, TRPC1 function as an endogenous Ca2+ entry channel and silencing of either TRPC1 or its activator, STIM1, significantly decreased TGFβ induced Ca2+ entry, inhibited TGFβ-mediated calpain activation and cell migration. In contrast, overexpression of TRPC1 showed increased Ca2+ entry and promoted TGFβ-mediated cell migration. Moreover, increased TRPC1 expression was observed in ductal carcinoma cells. Together these results suggest that disrupting Ca2+ influx via TRPC1/STIM1 mechanism reduces calpain activity, which could restore intercellular junction proteins thereby inhibiting EMT induced motility.

Calpain research for drug discovery: challenges and potential

Calpains are a family of proteases that were scientifically recognized earlier than proteasomes and caspases, but remain enigmatic. However, they are known to participate in a multitude of physiological and pathological processes, performing 'limited proteolysis' whereby they do not destroy but rather modulate the functions of their substrates. Calpains are therefore referred to as 'modulator proteases'. Multidisciplinary research on calpains has begun to elucidate their involvement in pathophysiological mechanisms. Therapeutic strategies targeting malfunctions of calpains have been developed, driven primarily by improvements in the specificity and bioavailability of calpain inhibitors. Here, we review the calpain superfamily and calpain-related disorders, and discuss emerging calpain-targeted therapeutic strategies.

Calpain-activated mTORC2/Akt pathway mediates airway smooth muscle remodelling in asthma

BACKGROUND

Allergic asthma is characterized by inflammation and airway remodelling. Airway remodelling with excessive deposition of extracellular matrix (ECM) and larger smooth muscle mass are correlated with increased airway responsiveness and asthma severity. Calpain is a family of calcium-dependent endopeptidases, which plays an important role in ECM remodelling. However, the role of calpain in airway smooth muscle remodelling remains unknown.

OBJECTIVE

To investigate the role of calpain in asthmatic airway remodelling as well as the underlying mechanism.

METHODS

The mouse asthma model was made by ovalbumin sensitization and challenge. Calpain conditional knockout mice were studied in the model. Airway smooth muscle cells (ASMCs) were isolated from smooth muscle bundles in airway of rats. Cytokines IL-4, IL-5, TNF-α, and TGF-β1, and serum from patients with asthma were selected to treated ASMCs. Collagen-I synthesis, cell proliferation, and phosphorylation of Akt in ASMCs were analysed.

RESULTS

Inhibition of calpain using calpain knockout mice attenuated airway smooth muscle remodelling in mouse asthma models. Cytokines IL-4, IL-5, TNF-α, and TGF-β1, and serum from patients with asthma increased collagen-I synthesis, cell proliferation, and phosphorylation of Akt in ASMCs, which were blocked by the calpain inhibitor MDL28170. Moreover, MDL28170 reduced cytokine-induced increases in Rictor protein, which is the most important component of mammalian target of rapamycin complex 2 (mTORC2). Blockage of the mTORC2 signal pathway prevented cytokine-induced phosphorylation of Akt, collagen-I synthesis, and cell proliferation of ASMCs and attenuated airway smooth muscle remodelling in mouse asthma models.

CONCLUSIONS AND CLINICAL RELEVANCE

Our results indicate that calpain mediates cytokine-induced collagen-I synthesis and proliferation of ASMCs via the mTORC2/Akt signalling pathway, thereby regulating airway smooth muscle remodelling in asthma.

Gene/protein expression of CAPN1/2-CAST system members is associated with ERK1/2 kinases activity as well as progression and clinical outcome in human laryngeal cancer

Recent evidence indicates the involvement of calpains (CAPNs), a family of cysteine proteases, in cancer development and progression, as well as the insufficient response to cancer therapies. The contribution of CAPNs and regulatory calpastatin (CAST) and ERK1/2 kinases to aggressiveness, disease course, and outcome in laryngeal cancer remains elusive. This study was aimed to evaluate the CAPN1/2-CAST-ERK1/2 enzyme system mRNA/protein level and to investigate whether they can promote the dynamic of tumor growth and prognosis. The mRNA expression of marker genes was determined in 106 laryngeal cancer (SCLC) cases and 73 non-cancerous adjacent mucosa (NCLM) controls using quantitative real-time PCR. The level of corresponding proteins was analyzed by Western Blot. SLUG expression, as indicator of pathological advancement was determined using IHC staining. Significant increases of CAPN1/2-CAST-ERK1/2 levels of mRNA/protein were noted in SCLC compared to NCLM (p < 0.05). As a result, a higher level of CAPN1 and ERK1 genes was related to larger tumor size, more aggressive and deeper growth according to TFG scale and SLUG level (p < 0.05). There were also relationships of CAPN1/2 and ERK1 with incidences of local/nodal recurrences (p < 0.05). An inverse association for CAPN1/2, CAST, and ERK1/2 transcripts was determined with regard to overall survival (p < 0.05). In addition, a higher CAPN1 and phospho-ERK1 protein level was related to higher grade and stage (p < 0.05) and was found to promote worse prognosis. This is the first study to show that activity of CAPN1/2- CAST-ERK1/2 axis may be an indicator of tumor phenotype and unfavorable outcome in SCLC.

Thymic Stromal Lymphopoietin Promotes Fibrosis and Activates Mitogen-Activated Protein Kinases in MRC-5 Cells

BACKGROUND Acute lung injury (ALI) is a life-threatening hypoxemic respiratory disorder with high incidence and mortality. ALI usually manifests as widespread inflammation and lung fibrosis with the accumulation of pro-inflammatory and pro-fibrotic factors and collagen. Thymic stromal lymphopoietin (TSLP) has a significant role in regulation of inflammation but little is known about its roles in lung fibrosis or ALI. This study aimed to define the role and possible regulatory mechanism of TSLP in lung fibrosis. MATERIAL AND METHODS We cultured human lung fibroblast MRC-5 cells and overexpressed or inhibited TSLP by the vector or small interfering RNA transfection. Then, the pro-fibrotic factors skeletal muscle actin alpha (α-SMA) and collagen I, and the 4 mitogen-activated protein kinases (MAPKs) - MAPK7, p38, extracellular signal-regulated kinase 1 (ERK1), and c-Jun N-terminal kinase 1 (JNK1) - were detected by Western blot. RESULTS Results showed that TSLP promoted the production of α-SMA and collagen I (P<0.001), suggesting that it can accelerate MRC-5 cell fibrosis. It also activated the expression of MAPK7, p-p38, p-ERK1, and p-JNK1, but the total MAPK7, p-38, ERK1, and JNK1 protein levels were mostly unchanged, indicating the activated MAPK pathways that might contribute to the promotion of cell fibrosis. CONCLUSIONS This study shows the pro-fibrotic role of TSLP in MRC-5 cells, suggesting TSLP is a potential therapeutic target for treating lung fibrosis in ALI. It possibly functions via activating MAPKs. These findings add to our understanding of the mechanism of fibrosis.

IL-27 attenuates the TGF-β1-induced proliferation, differentiation and collagen synthesis in lung fibroblasts

AIMS

Pulmonary fibrosis is a type of chronic lung disease and has characteristics that progress quickly, has a high fatality rate and a poor therapeutic effect. Our previous research showed that interleukin-27(IL-27) potentially attenuates BLM-induced pulmonary fibrosis, but the function of IL-27 in lung fibroblasts (LFs) differentiation pulmonary fibrosis is yet to be known.

MAIN METHODS

Here we investigated the effect of IL-27 on the proliferation, differentiation and collagen synthesis of lung fibroblasts induced by transforming growth factor-β1 (TGF-β1)using MTT, bromodeoxyuridine(BrdU) staining, real-time quantitative PCR(qPCR), Western blot, cell cycle FACS assay and immunofluorescence. We also examined the expression of the JAK/STAT and TGF-β1/Smad signaling pathway of IL-27 in lung fibroblasts.

KEY FINDINGS

TGF-β1 treated lung fibroblasts showed significantly increased proliferation, differentiation and collagen synthesis as well as overactivated JAK/STAT and TGF-β1/Smad signaling. However, the presence of IL-27 weakened these effects and obviously inactivated the JAK/STAT and TGF-β1/Smad signaling pathways.

SIGNIFICANCE

Our results indicate that IL-27 may play an anti-fibrotic role in the development, differentiation and collagen synthesis in lung fibroblasts. These data also may provide a target gene therapy method in treating pulmonary fibrosis.