Induction of matrix metalloproteinase-1 by small interfering RNA targeting connective tissue growth factor in dermal fibroblasts from patients with systemic sclerosis

Plasma Glycosaminoglycan Profiles in Systemic Sclerosis: Associations with MMP-3, MMP-10, TIMP-1, TIMP-2, and TGF-Beta

The aim of the study was to determine whether plasma levels of total glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) (MMP-3, MMP-10), and their tissue inhibitors (TIMPs) (TIMP-1, TIMP-2) as well as transforming growth factor β (TGF-β) differ in the patients with systemic sclerosis (SSc) in relation to the healthy subjects. Plasma samples were obtained from 106 people (64 patients with SSc and 42 healthy individuals) and measured for MMP-3, MMP-10, TIMP-1, TIMP-2, and TGF-β levels using ELISA methods. GAGs isolated from plasma samples were quantified using a hexuronic acid assay. The plasma levels of total GAGs, TIMP-1, TIMP-2, and TGF-β were significantly higher, while MMP-3 was significantly decreased in SSc patients compared to the controls. We have revealed a significant correlation between plasma GAGs and TGF-β (r = -0.47) and TIMP-2 (r = 0.38), respectively. The results of this study revealed that remodeling of the extracellular matrix, reflected by quantitative changes in plasma glycosaminoglycans, occurs during systemic sclerosis. Thus, the alterations in GAG metabolism connected with SSc may lead to systemic changes in the properties of the connective tissue extracellular matrix.

2-Methoxyestradiol inhibits hypoxia-induced scleroderma fibroblast collagen synthesis by phosphatidylinositol 3-kinase/Akt/mTOR signalling

Objectives

To investigate the mechanism of 2-methoxyestradiol (2-ME) in inhibiting hypoxia-induced collagen synthesis of fibroblasts in SSc.

Methods

The expressions of hypoxia-inducible factor 1 alpha (HIF-1α) and connective tissue growth factor (CTGF) in skin specimens derived from SSc patients and healthy volunteers were examined by immunohistochemistry. HIF-1α was knocked down by lentiviral transduction, and SSc dermal fibroblasts cultured under normoxic (21% O2) or hypoxic (1% O2) condition were treated with PI3K inhibitor LY294002, rapamycin or 2-ME (25 μM). The protein levels of HIF-1α, CTGF, collagen I, p-Akt and p-mTOR were examined by western blotting or immunofluorescence. Apoptosis and cell cycle of fibroblasts were assessed by flow cytometry and by measuring caspase 3 activity, and cell proliferation was evaluated by Cell Counting Kit-8.

Results

The expressions of HIF-1α and CTGF were increased in skins of SSc patients compared with healthy controls. Hypoxia up-regulated the protein levels of HIF-1α, CTGF and collagen I in SSc fibroblasts. In contrast, 2-ME inhibited PI3K/Akt/mTOR pathway and down-regulated protein levels of HIF-1α, CTGF and collagen I. Knockdown of HIF-1α reduced expressions of CTGF and collagen I, which were further down-regulated by 2-ME intervention. Moreover, 2-ME promoted the apoptosis and inhibited the proliferation of SSc fibroblasts by arresting the cell cycle at the G2/M phase.

Conclusion

2-ME reduced the production of CTGF and collagen I in SSc fibroblasts induced by hypoxia through PI3K/Akt/mTOR/HIF-1α signalling and inhibited the proliferation of fibroblasts. These findings suggested that 2-ME could be employed as a promising antifibrotic therapy for SSc.

Inhibition of connective tissue growth factor attenuates paraquat-induced lung fibrosis in a human MRC-5 cell line

Chronic exposure to Paraquat (PQ) may result in progressive pulmonary fibrosis and subsequent chronic obstructive pulmonary malfunction. Connective tissue growth factor (CTGF) has been proposed as a key determinant in the development of lung fibrosis. We investigated thus whether knock down of CTGF can prevent human lung fibroblasts (MRC-5) activation and proliferation with the subsequent inhibition of PQ-induced fibrosis. MRC-5 was transfected with CTGF-siRNAs and exposed to different concentrations of PQ. The siRNA-silencing efficacy was evaluated using western blotting analyses, qRT-PCR and flow cytometry. Next, the viability and migration of MRC-5 was determined. MMP-2, MMP-9, and TIMP-1 accumulation were quantified to evaluate the lung fibrosis exposure to PQ. Over expression of CTGF mRNA was observed in human MRC-5 cell as early as 6 h following PQ stimulation. CTGF gene expression in MRC-5 cells was substantially reduced by RNAi, which significantly suppressed the expression of the lung fibrosis markers such as tissue inhibitor of metalloproteinase-2 (TIMP-2), Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9) that were stimulated by PQ. Inhibition of CTGF expression suppressed impeded the proliferation and migration ability of MRC-5 cells and resulted in cell-extracellular matrix (ECM) protein accumulation in cells. Our results suggest that CTGF promoted the development of PQ-induced lung fibrosis in collaboration with transforming growth factor β1 (TGFβ1). Furthermore, the observed arresting effects of CTGF knock down during this process suggested that CTGF is the potential target site for preventing PQ-induced pulmonary fibrosis. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1620-1626, 2016.

Understanding Fibroblasts in Order to Comprehend the Osteopathic Treatment of the Fascia

The osteopathic treatment of the fascia involves several techniques, each aimed at allowing the various layers of the connective system to slide over each other, improving the responses of the afferents in case of dysfunction. However, before becoming acquainted with a method, one must be aware of the structure and function of the tissue that needs treating, in order to not only better understand the manual approach, but also make a more conscious choice of the therapeutic technique to employ, in order to adjust the treatment to the specific needs of the patient. This paper examines the current literature regarding the function and structure of the fascial system and its foundation, that is, the fibroblasts. These connective cells have many properties, including the ability to contract and to communicate with one another. They play a key role in the transmission of the tension produced by the muscles and in the management of the interstitial fluids. They are a source of nociceptive and proprioceptive information as well, which is useful for proper functioning of the body system. Therefore, the fibroblasts are an invaluable instrument, essential to the understanding of the therapeutic effects of osteopathic treatment. Scientific research should make greater efforts to better understand their functioning and relationships.

Silk fibroin–keratin based 3D scaffolds as a dermal substitute for skin tissue engineering

Development of highly vascular dermal tissue-engineered skin substitutes with appropriate mechanical properties and cellular cues is in need for significant advancement in the field of dermal reconstruction.

Cells from the skin of patients with systemic sclerosis secrete chitinase 3-like protein 1

Background

The chitinase-like protein, Chi3L1, is associated with increased fibrotic activity as well as inflammatory processes. The capacity of skin cells from systemic sclerosis (SSc) patients to produce Chi3L1, and the stimulation of its synthesis by cytokines or growth factors known to be associated with SSc, was investigated.

Methods

Cells were isolated from forearm and/or abdomen skin biopsies taken from SSc patients and normal individuals and stimulated with cytokines and growth factors to assess Chi3L1 expression. Chi3L1-expressing cells were characterized by immunohistochemical staining.

Results

Chi3L1 was not secreted by skin cells from normal individuals nor was its synthesis induced by any of the cytokines or growth factors investigated. In contrast, Chi3L1 secretion was induced by OSM or IL-1 in cells from all forearm biopsies of SSc patients, and endogenous secretion in the absence of cytokines was detected in several specimens. Patients with Chi3L1-producing cells at both the arm and abdomen had a disease duration of less than 3 years. Endogenous Chi3L1 production was not a property of the major fibroblast population nor of myofibroblasts, but rather was related to the presence of stem-like cells not present in normal skin. Other cells, however, contributed to the upregulation of Chi3L1 by OSM.

Conclusions

The emergence of cells primed to respond to OSM with increased Chi3L1 production appears to be associated with pathological processes active in SSc.

General significance

The presence of progenitor cells expressing the chilectin Chi3L1 in SSc skin appears to play a role in the initiation of the disease process.

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Cells isolated from the skin of scleroderma patients secrete Chi3L1.

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Chi3L1 production is stimulated by oncostatin M or interleukin 1.

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Patients with Chi3L1 producing cells have disease duration of < 3 years.

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Chi3L1 production is a property of stem-like cells not present in normal skin.

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Other cells contribute to Chi3L1 upregulation by oncostatin M.

RNA Interference Targeting Connective Tissue Growth Factor Inhibits the Transforming Growth Factor- β 2 Induced Proliferation in Human Tenon Capsule Fibroblasts

Purpose. This study was to determine the effect of CTGF-small interfering RNA (siRNA) on TGF- β 2-induced proliferation in human Tenon capsule fibroblasts (HTFs). Methods. HTFs were transfected with four of CTGF-siRNAs separately for screening of gene silencing efficacy that was determined by transcript level measured by quantitative real-time PCR (qRT-PCR). Recombinant TGF- β 2 was added into the culture to stimulate the proliferation of HTFs. The gene silencing efficacy of the siRNAs was evaluated by qRT-PCR and immunofluorescence of CTGF transcript and protein levels. The viability of HTFs was determined by cell counting kit-8 (CCK-8). FCM was used to assess cell cycle after CTGF-siRNA transfection. Results. The expression of CTGF and proliferation of HTFs were increased significantly by TGF- β 2 stimulation. The transfection of CTGF-siRNA abolished the upregulation of CTGF and cell proliferation induced by TGF- β 2. The analysis of cell cycle indicated that CTGF-siRNA treatment stimulated cells from S phase to G0/G1 phase in comparison with the inverse physiologic function of TGF- β 2. Conclusion. CTGF targeting siRNA could effectively suppress the expression of CTGF and attenuate the proliferation of HTFs. The siRNA approach may provide a therapeutic option for eliminating filtration bleb scarring after glaucoma filtration surgery (GFS).

Novel biodegradable porous scaffold applied to skin regeneration

Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.

Connective tissue growth factor, matrix regulation, and diabetic kidney disease

PURPOSE OF REVIEW

Connective tissue growth factor, more recently officially known as CCN-2, is a member of the CCN family of secreted cysteine-rich modular matricellular proteins. Here, we review CCN-2 in diabetic nephropathy with focus on its regulation of extracellular matrix.

RECENT FINDINGS

CCN-2 is upregulated in the clinical and preclinical models of diabetic nephropathy by multiple stimuli, including elevated glucose, advanced glycation, some types of lipid, various hemodynamic factors, as well as hypoxia and oxidative stress. CCN-2 has bioactivities that suggest it may mediate diabetic nephropathy pathogenesis, especially in extracellular matrix accumulation, through both induction of new matrix and inhibition of matrix degradation. CCN-2 also has proinflammatory functions. Moreover, recent studies using antibodies or antisense technologies in animal and early phase clinical trial settings have shown that inhibition of renal CCN-2 expression or action may prevent diabetic nephropathy. Additionally, determination of renal and blood levels of CCN-2 as a marker of diabetic renal disease and its progression appears to have value.

SUMMARY

Recent publications implicate CCN-2 as both an evolving marker and mediator of diabetic nephropathy.

Cyclic mechanical stress downregulates endothelin-1 and its responsive genes independently of TGFβ1 in dermal fibroblasts

Mechanical forces are highly variable ranging from the ubiquitous gravity force to compression, fluid shear, torsion, tension and other forms. Mechanical forces act on cells and modulate their biological responses by regulating gene transcription, enzyme and growth factor activity. In soft connective tissues, formation of myofibroblasts strictly requires a mechanically loaded environment in addition to local transforming growth factor (TGF)-β activity, which itself can be modulated by the mechanical status of the environment. The aim of this study was to monitor the adaptive responses of primary dermal fibroblasts towards cyclic mechanical stress under conditions of high force to better understand the regulation of gene expression in normal skin and mechanisms of gene regulation in mechanically altered fibrotic skin. Primary murine dermal fibroblasts were exposed to equi-biaxial tensile strain. Cyclic mechanical tension was applied at a frequency of 0.1 Hz (6× /min) for 24 h with a maximal increase in surface area of 15%. This treatment resulted in downregulation of alpha smooth muscle actin (αSMA) and connective tissue growth factor (CTGF) but not of TGFβ1 expression. Cyclic strain also strongly reduced endothelin-1 (ET-1) expression and supplementing strained cultures with exogenous ET-1 rescued αSMA and CTGF levels. Of note, no biologically significant levels of TGFβ1 activity were detected in strained cultures. We provide evidence for a novel, TGFβ1-independent mechanism regulating ET-1 expression in dermal fibroblasts by biomechanical forces. Modulation of ET-1-dependent activities regulates downstream fibrotic marker genes; this pathway might therefore provide an approach to attenuate myofibroblast differentiation.

IFN-γ and TNF-α synergize to inhibit CTGF expression in human lung endothelial cells

Connective tissue growth factor (CTGF/CCN2) is an angiogenetic and profibrotic factor, acting downstream of TGF-β, involved in both airway- and vascular remodeling. While the T-helper 1 (Th1) cytokine interferon-gamma (IFN-γ) is well characterized as immune-modulatory and anti-fibrotic cytokine, the role of IFN-γ in lung endothelial cells (LEC) is less defined. Tumour necrosis factor alpha (TNF-α) is another mediator that drives vascular remodeling in inflammation by influencing CTGF expression. In the present study we investigated the influence of IFN-γ and TNF-α on CTGF expression in human LEC (HPMEC-ST1.6R) and the effect of CTGF knock down on human LEC. IFN-γ and TNF-α down-regulated CTGF in human LEC at the promoter-, transcriptional- and translational-level in a dose- and time-dependent manner. The inhibitory effect of IFN-γ on CTGF-expression could be almost completely compensated by the Jak inhibitor AG-490, showing the involvement of the Jak-Stat signaling pathway. Besides the inhibitory effect of IFN-γ and TNF-α alone on CTGF expression and LEC proliferation, these cytokines had an additive inhibitory effect on proliferation as well as on CTGF expression when administered together. To study the functional role of CTGF in LEC, endogenous CTGF expression was down-regulated by a lentiviral system. CTGF silencing in LEC by transduction of CTGF shRNA reduced cell proliferation, but did not influence the anti-proliferative effect of IFN-γ and TNF-α. In conclusion, our data demonstrated that CTGF was negatively regulated by IFN-γ in LEC in a Jak/Stat signaling pathway-dependent manner. In addition, an additive effect of IFN-γ and TNF-α on inhibition of CTGF expression and cell proliferation could be found. The inverse correlation between IFN-γ and CTGF expression in LEC could mean that screwing the Th2 response to a Th1 response with an additional IFN-γ production might be beneficial to avoid airway remodeling in asthma.

Elevated MMP-7 levels in patients with systemic sclerosis: correlation with pulmonary involvement

BACKGROUND

Fibrosis is characterized by an excessive accumulation of connective tissue because of an imbalance between synthesis and degradation of extracellular matrix proteins. Systemic sclerosis (SSc) is a prototypic chronic inflammatory disease leading to a severe fibrosis of the skin and many internal organs. QUESTIONS ADDRESSED: We investigated whether serum MMP-7 levels reflect the activity of the fibrotic reaction in systemic sclerosis.

EXPERIMENTAL DESIGN

Serum samples were obtained from 123 patients with systemic sclerosis. MMP-serum levels of all patients with SSc were compared with age-matched healthy controls.

RESULTS

Significantly increased median serum MMP-7 levels were found in patients with SSc when compared with controls. The median MMP-7 serum level of patients with lung fibrosis (LF) was significantly higher compared with those without LF. Accordingly, patients with dyspnea and DLCO (diffusion capacity of the lung for carbon monoxide) levels below 60% showed significantly higher median MMP-7 levels.

CONCLUSIONS

Elevated MMP-7 levels are associated with an advanced stage of SSc and LF. These data suggest that in SSc MMP-7 is involved in the process of fibrotic tissue remodelling.

Autoimmune mechanisms of scleroderma and a role of oxidative stress

Scleroderma is a fibrotic condition characterized by immunological abnormalities, vascular injury and increased accumulation of extracellular matrix proteins in the skin. Although the etiology of scleroderma has not yet been fully elucidated, a growing body of evidence suggests that extracellular matrix overproduction by activated fibroblasts results from complex interactions among endothelial cells, lymphocytes, macrophages and fibroblasts via a number of mediators, such as cytokines, chemokines and growth factors. Recent investigations have further suggested that reactive oxygen species (ROS) are involved and play a role of autoimmunology in scleroderma. In this review, current findings on the autoimmune mechanisms in the pathophysiology of scleroderma are described.