Mechanism of the transforming growth factor-beta induction of fibronectin expression in hepatic stem-like cells

Role of Cytokines on the Progression of Liver Fibrosis in Mice Infected with Echinococcus multilocularis

Background

Liver fibrosis is a significant pathological change of Echinococcus multilocularis (E. multilocularis) infection. This study aimed to explore the role of cytokines on the progression of liver fibrosis in mice infected with E. multilocularis.

Methods

Liver histopathological features at 2, 8, 30, 90 and 180 d were quantified by inflammatory severity score. The expression levels of inflammatory cytokines, fibrosis-related cytokines and hepatic cell apoptosis were measured using qRT-PCR and immunohistochemistry.

Results

At the early stage of infection, parasite stimulation triggers the rapid recruitment of immune cells, such as macrophages and neutrophils. These infiltrated immune cells then produce a large number of cytokines, such as iNOS (inducible nitric oxide synthase), a pro-inflammatory cytokine; TGF-β (transforming growth factor) activated HSCs (hepatic stellate cells) to promote the proliferation of fibroblasts and secretion of ECM (extracellular matrix); MMP9 (matrix metalloproteinase 9) degraded basal ECM and facilitated its replacement by a highly dense interstitial matrix. At the middle and late stages of infection, the expression of IL-10 (interleukin-10) with general inhibitory effect was increased. The imbalance of fiber formation and degradation aggravated liver fibrosis. Meanwhile, the whole process of E. multilocularis infection was accompanied by the necrosis and apoptosis of hepatic cells.

Conclusion

Along with the expansion of parasitic infection, dynamic changes in cytokine expression were observed on the liver fibrosis progression, which is helpful to provide some new ideas for the prevention and treatment of liver fibrosis in mice infected with E. multilocularis.

Chlorogenic Acid Inhibits Liver Fibrosis by Blocking the miR-21-Regulated TGF-β1/Smad7 Signaling Pathway in Vitro and in Vivo

Aims: Chlorogenic acid (CGA) is a phenolic acid that has a wide range of pharmacological effects. However, the protective effects and mechanisms of CGA on liver fibrosis are not clear. This study explored the effects of CGA on miR-21-regulated TGF-β1/Smad7 liver fibrosis in the hepatic stellate LX2 cell line and in CCl4-induced liver fibrosis in Sprague-Dawley rats.

Methods: The mRNA expression of miR-21, Smad7, connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase 1 (TIMP-1), matrix metalloproteinase-9 (MMP-9), and transforming growth factor-β1 (TGF-β1) and the protein levels of Smad2, p-Smad2, Smad3, p-Smad3, Smad2/3, p-Smad2/3, Smad7, CTGF, α-SMA, TIMP-1, MMP-9 and TGF-β1 were assayed in LX2 cells and liver tissue. The effects of CGA after miR-21 knockdown or overexpression were analyzed in LX2 cells. The liver tissue and serum were collected for histopathological examination, immunohistochemistry (IHC) and ELISA.

Results: The mRNA expression of miR-21, CTGF, α-SMA, TIMP-1, and TGF-β1 and the protein expression of p-Smad2, p-Smad3, p-Smad2/3, CTGF, α-SMA, TIMP-1, and TGF-β1 were inhibited by CGA both in vitro and in vivo. Meanwhile, CGA elevated the mRNA and protein expression of Smad7 and MMP-9. After miR-21 knockdown and overexpression, the downstream molecules also changed accordingly. CGA also lessened the degree of liver fibrosis in the pathological manifestation and reduced α-SMA and collagen I expression in liver tissue and TGF-β1 in serum. Conclusion: CGA might relieve liver fibrosis through the miR-21-regulated TGF-β1/Smad7 signaling pathway, which suggests that CGA might be a new anti-fibrosis agent that improves liver fibrosis.

Regeneration of full-thickness skin defects by differentiated adipose-derived stem cells into fibroblast-like cells by fibroblast-conditioned medium

Background

Fibroblasts are ubiquitous cells in the human body and are absolutely necessary for wound healing such as for injured skin. This role of fibroblasts was the reason why we aimed to differentiate human adipose-derived stem cells (hADSCs) into fibroblasts and to test their wound healing potency. Recent reports on hADSC-derived conditioned medium have indicated stimulation of collagen synthesis as well as migration of dermal fibroblasts in wound sites with these cells. Similarly, human fibroblast-derived conditioned medium (F-CM) was reported to contain a variety of factors known to be important for growth of skin. However, it remains unknown whether and how F-CM can stimulate hADSCs to secrete type I collagen.

Methods

In this study, we obtained F-CM from the culture of human skin fibroblast HS27 cells in DMEM media. For an in-vivo wound healing assay using cell transplantation, balb/c nude mice with full-thickness skin wound were used.

Results

Our data showed that levels of type I pro-collagen secreted by hADSCs cultured in F-CM increased significantly compared with hADSCs kept in normal medium for 72 h. In addition, from a Sircol collagen assay, the amount of collagen in F-CM-treated hADSC conditioned media (72 h) was markedly higher than both the normal medium-treated hADSC conditioned media (72 h) and the F-CM (24 h). We aimed to confirm that hADSCs in F-CM would differentiate into fibroblast cells in order to stimulate wound healing in a skin defect model. To investigate whether F-CM induced hADSCs into fibroblast-like cells, we performed FACS analysis and verified that both F-CM-treated hADSCs and HS27 cells contained similar expression patterns for CD13, CD54, and CD105, whereas normal medium-treated hADSCs were significantly different. mRNA level  analysis for Nanog, Oct4A, and Sox2 as undifferentiation markers and vimentin, HSP47, and desmin as matured fibroblast markers supported the characterization that hADSCs in F-CM were highly differentiated into fibroblast-like cells. To discover the mechanism of type I pro-collagen expression in hADSCs in F-CM, we observed that phospho-smad 2/3 levels were increased in the TGF-β/Smad signaling pathway. For in-vivo analysis, we injected various cell types into balb/c nude mouse skin carrying a 10-mm punch wound, and observed a significantly positive wound healing effect in this full-thickness excision model with F-CM-treated hADSCs rather than with untreated hADSCs or the PBS injected group.

Conclusions

We differentiated F-CM-treated hADSCs into fibroblast-like cells and demonstrated their efficiency in wound healing in a skin wound model.

Anti-hepatic fibrosis effects of a novel turtle shell decoction by inhibiting hepatic stellate cell proliferation and blocking TGF-β1/Smad signaling pathway in rats

Hepatic fibrosis (HF), a wound-healing response to a variety of chronic stimuli, is characterized by the excessive synthesis of extracellular matrix (ECM) proteins by hepatic stellate cells (HSC) and eventually the development of hepatic cirrhosis. Turtle shell pill (TSP) is a common traditional Chinese medicine used for preventing and treating HF and early hepatic cirrhosis, but its side-effects and the shortage of ingredients limit its clinical application. In addition, its mechanism of action is not clear. In the present study, we first improved the original formula of TSP to produce a novel turtle shell decoction (NTSD) with less toxicity and easier accessible materials. In a carbon tetrachloride (CCl4)-induced HF rat model, we observed that NTSD and TSP had similar effects on the improvement of liver functions in rats, including a decrease in serum alanine amino transferase (ALT) and aspartate amino transferase (AST) serum concentrations and increased albumin content in addition to a marked attenuation of CCl4-induced liver damage and fibrosis. NTSD containing rat serum inhibited rat liver stellate cell line HSC-T6 cell proliferation and induced cell apoptosis in vitro. Moreover, the NTSD treatment significantly decreased the transforming growth factor beta 1 (TGF-β1) and Smad3 gene expression and increased inhibitory Smad7 gene expression in liver tissues of HF rats, suggesting that NTSD inhibited the ECM expression of HSC by downregulating the TGF-β1/Smad signaling pathway. The results of our rat model study revealed that NTSD showed good in vitro and in vivo anti-HF effects via proliferation inhibition and the induction of apoptosis of HSCs and blocked the TGF-β1/Smad signaling pathway.

Effects of TRAP-1-like protein (TLP) gene on collagen synthesis induced by TGF-β/Smad signaling in human dermal fibroblasts

BACKGROUND

Hypertrophic scars are pathologic proliferations of the dermal skin layer resulting from excessive collagen deposition during the healing process of cutaneous wounds. Current research suggests that the TGF-β/Smad signaling pathway is closely associated with normal scar and hypertrophic scar formation. TRAP-1-like protein (TLP), a cytoplasmic protein, has been reported to efficiently regulate Smad2- and Smad3-dependent signal expression in the TGF-β pathway. The relationship between TLP and Type I/III collagen (Col I/III) synthesis explored in the present study provides an effective target for wound healing and gene therapy of hypertrophic scarring.

OBJECTIVE

To investigate the effects of TLP on collagen synthesis in human dermal fibroblasts.

METHODS

Lentiviral vectors encoding TLP was constructed to transfect fibroblasts derived from normal human skin. The expression of Col I/III and phosphorylation of Smad2 and Smad3 in fibroblasts were examined after TLP treatment. In addition, the comparison of TLP expression in normal skin tissues and in hypertrophic scar tissues was performed, and the effect of TLP on cell viability was analyzed by MTT assay.

RESULTS

TLP expression in hypertrophic scar tissue was markedly higher than in normal skin tissue. The Real Time PCR and Western blot test results both revealed that the synthesis of Col I/III was positively correlated with the expression of TLP. TLP also facilitate Smad2 phosphorylation while, conversely, inhibiting Smad3 phosphorylation. TLP may play a cooperative role, along with the cytokine TGF-β1, in improving the overall cell viability of skin fibroblasts.

CONCLUSIONS

TLP likely acts as a molecular modulator capable of altering the balance of Smad3- and Smad2-dependent signaling through regulation of phosphorylation, thus facilitating collagen synthesis in fibroblasts. Based on genetic variation in TLP levels in different tissues, these results suggest that TLP plays a key role in the process of TGF-β1/Smad3 signaling that contributes to wound healing and genesis of pathologic scars.

Serum TGF-β, Serum MMP-1, and HOMA-IR as non-invasive predictors of fibrosis in Egyptian patients with NAFLD

BACKGROUND/AIM

Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent cause of chronic liver disease worldwide. A number of these patients progress to nonalcoholic steatohepatitis (NASH) which carries significant morbidity and mortality. The aim of this study is to evaluate the diagnostic value of serum levels of transforming growth factor beta-1 (TGF-β1) matrix metalloproteinase-1 (MMP-1), and insulin resistance as predictors of fibrosis in Egyptian NAFLD patients.

PATIENTS AND METHODS

Fifty patients with NAFLD and different stages of fibrosis were studied. Serum levels of TGF-β1, MMP-1, and fasting serum insulin were measured; calculation of the homeostasis model assessment for insulin resistance (HOMA-IR) was done.

RESULTS

TGF-β1 gives a sensitivity of 100% and specificity of 94.4% for stage 1 fibrosis, 100% and 93.9%, respectively, for stage 2 fibrosis, and 97.7% and 100%, respectively, for stage 3 fibrosis. MMP-1 showed sensitivity and specificity of 88% and 81.8%, respectively, for stage 2 fibrosis, 90.9% and 55.56%, respectively, for stage 3 fibrosis, but it is of no diagnostic value in stage 1 fibrosis.

CONCLUSION

Serum TGF-β1, MMP-1, and insulin resistance (HOMA-IR) proved to be potentially useful noninvasive markers in predicting fibrosis in NASH patients.

Investigation of thrombospondin-1 and transforming growth factor-β expression in the heart of aging mice

Elderly patients face the problems of morbidity and mortality due to age-mediated disabilities. The purpose of the present study was to investigate the expression of thrombospondin-1 (TSP-1) and transforming growth factor-β (TGF-β) in aging mice, and its probable mechanism in the pathological changes of aging myocardium. The aging model group (AM) comprised 30-month-old mice, while the control group comprised 2-month-old mice. The pathological changes were explored by H&E staining, and the contents of superoxide dismulase (SOD) and malondialdehyde (MDA) in the hearts were determined by xanthine oxidation or TBA colorimetry. TSP-1 and TGF-β expression in the left ventricular myocardium was also measured by immunohistochemistry. The results showed that the activities of SOD decreased and the MDA content increased markedly in the hearts of the AM group compared to the control group. H&E staining showed that the control group myocardial cells lined up in order with clear structure and stained equably, while the AM group myocardial cells lined up in disorder with an augmented cell body and the appearance of many granules and interstitial fibrosis. Compared to the control group, in the hearts of the AM group, TSP-1 and TGF-β protein expression in myocardial cells showed a significant increase (P<0.01). TSP-1 and TGF-β expression increased in the myocardium, which may be related to pathological changes of age-related heart diseases, such as hypertrophy, fibrosis of myocardial cells and microvessel dissepiment thickening.