Connective tissue growth factor (CTGF/CCN2) in serum is an indicator of fibrogenic progression and malignant transformation in patients with chronic hepatitis B infection

Serum biomarkers for liver fibrosis

Liver fibrosis is a common pathway in most chronic liver diseases, characterized by excessive extracellular matrix accumulation. Without treatment, fibrosis will ultimately result in cirrhosis, portal hypertension, and even liver failure. It is considered that liver fibrosis is reversible while cirrhosis is not, making it significant to diagnose and evaluate liver fibrogenesis timely. As the gold standard, liver biopsy is imperfect due to its invasiveness and sampling error. Therefore, attempts at uncovering noninvasive tests have become a hot topic in liver fibrosis. Nowadays, as an important category of noninvasive tests, serum biomarkers, which are safer, convenient, repeatable, and more acceptable, are widely discussed and commonly used in clinical practice. Serum biomarkers of liver fibrosis can be divided into class I (direct) and classⅡ (indirect) markers. However, the diagnostic efficiency still varies among studies. This article summarizes the most established and newly discovered serum biomarkers for hepatic fibrogenesis.

The value of plasma hypoxia markers for predicting imaging-based hypoxia in patients with head-and-neck cancers undergoing definitive chemoradiation

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Higher osteopontin plasma levels correlate with more hypoxic tumors at baseline.

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Increased baseline osteopontin levels are associated with residual tumor hypoxia.

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Absent early hypoxia response is linked with higher VEGF and CTGF levels in week 5.

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Plasma hypoxic markers may serve as biomarkers favoring radiotherapy personalization.

Background

Methods

Results

Conclusion

Dietary grape pomace - effects on growth performance, intestinal health, blood parameters, and breast muscle myopathies of broiler chickens

The search for alternatives to antibiotics in poultry production is still on-going and has been directed towards investigation of the efficacy of different potential alternatives. However, it is important that the sought alternatives are cost-efficient and have no negative impact on meat quality, for ease of adoption and profit maximization. This study aimed at exploiting an agro-industrial waste, grape pomace (GP) as an alternative to in-feed antibiotics and assessing the effects on growth, intestinal morphology, ceca microbiota, ceca short-chain fatty acid (SCFA) concentration, blood biochemical parameters, and breast muscle myopathies of broiler chickens. A total of 576 one-day-old Cobb-500 broiler chicks were randomly allotted to 3 dietary treatments - Negative control (NC, a corn-wheat soybean-based diet), NC + 0.05% bacitracin methylene disalicylate (BMD), and NC + 2.5% GP. Each treatment was assigned to 8 replicate pens with 25 birds per pen. Body weight (BW), feed intake (FI), and feed conversion ratio (FCR) were determined weekly. On d 36, 2 chickens/pen were euthanized for measuring blood biochemical parameters, ceca SCFA, and ceca microbiota. White striping (WS) and wooden breast (WB) incidence were assessed in 4 chickens/pen on d 42. The GP diet increased (P < 0.05) average FI throughout the feeding phases compared to the other treatments, but overall FCR was similar. Birds in the GP treatment had higher (P < 0.05) villus height (VH) and increased VH:crypt depth ratio in the duodenum and jejunum compared to other treatments. The level of ceca SCFA and the incidence of WS and WB was the same for all treatments. Plasma Ca and P were significantly higher (P < 0.05) in birds fed GP and BMD, compared to the NC. Birds in the GP treatment had significantly reduced (P < 0.05) plasma aspartate transaminase than other treatments. Birds receiving GP had a higher (P < 0.05) relative abundance of the phylum Bacteroidetes and reduced (P < 0.05) Firmicutes compared to other treatments. The relative abundance of Bacteroides and Lactobacillus genera were higher (P < 0.05) among birds fed GP compared to other treatments. Inclusion of 2.5% GP in broiler chicken diets improved gut morphology and modified the cecal bacterial community and blood biochemical profiles with no adverse effect on growth performance and meat quality.

Connective Tissue Growth Factor in Digestive System Cancers: A Review and Meta-Analysis

Aim

A meta-analysis was conducted to estimate the impact of connective tissue growth factor (CTGF) on outcomes in patients with digestive system cancers.

Methods

A systemic literature survey was performed by searching the Cochrane Library and PubMed databases for articles that evaluated the impact of CTGF on outcomes in patients with digestive system cancers. Hazard ratios and 95% confidence intervals were calculated for prognostic factors, overall and recurrence-free survival using RevMan 5.3 software.

Results

This meta-analysis was conducted to evaluate a total of 11 studies that included 1730 patients. The results showed that elevated CTGF expression was significantly correlated with advanced age, larger tumor size, multiple tumors, and vascular invasion. Subgroup analysis by cancer type revealed increased risk for lymph node metastasis and advanced tumor node metastasis (TNM) stage in gastric cancer, compared with colorectal cancer. An unfavorable effect of elevated CTGF levels on overall survival was found in patients with hepatocellular carcinoma and patients with gastric cancer, while survival was improved in colorectal cancer patients with high CTGF expression, compared to those with normal levels of CTGF.

Conclusions

Elevated CTGF expression may be a novel biomarker for disease status and predicted survival outcomes in patients with specific digestive system cancers.

H2S attenuates the myocardial fibrosis in diabetic rats through modulating PKC-ERK1/2MAPK signaling pathway

OBJECTIVE

To investigate the roles and underlying mechanism of exogenous H2S (hydrogen sulfide) in attenuating the myocardial fibrosis in diabetic rats.

METHODS:

A total of 40 SD rats were randomly divided into 4 groups: control group, STZ group, STZ + H2S group and H2S group. To build the DM rat model , the rats in the STZ group and STZ + H2S group were injected streptozotocin (STZ) intraperitoneally, While the rats in the STZ + H2S group and the H2S group received sodium hydrosulfide (NaHS), which provides exogenous H2S. Eight weeks later, the myocardial tissues of rats were used to detecting the collagen deposition through Masson staining, as well as some protein expressions related to myocardial fibrosis and signaling pathway by western blotting.

RESULTS:

Comparing to control group, the collagen deposition of myocardial matrix remarkably increased in the STZ group, and almost all the proteins that are relative to myocardial fibrosis, inflammatory and signaling pathway show an overexpression, except for PPARG and NF-κBp65. When Compared with the STZ group, the collagen deposition was obviously attenuated in STZ + H2S group, as well as the protein expressions above-mentioned, While PPARG was up-regulated.

CONCLUSION:

The myocardial fibrosis in DM rats can be attenuated effectively by exogenous H2S, and the underlying mechanism is likely to regulating PKC-ERK1/2MAPK signaling pathway, improving the MMPs/TIMPs expression dysregulation and inhibiting inflammatory reaction.

Functionalized aptamer with an antiparallel G-quadruplex: Structural remodeling, recognition mechanism, and diagnostic applications targeting CTGF

Connective tissue growth factor (CTGF), a widely used biomarker, is involved in many diseases, such as diabetic retinopathy, diabetic nephropathy, and rheumatoid arthritis, and it is often over-expressed in human malignant tumors. Therefore, sensitive, specific and efficient detection methods for CTGF are needed for the early diagnosis and assessment of prognosis. In this study, an aptamer, APT1, that specifically binds to CTGF was obtained by SELEX technology. Circular dichroism spectroscopy indicated that APT1 formed interconvertible parallel and antiparallel G-quadruplexes. Mutation and truncation strategies optimized APT1 and improved its functions, yielding APT1M6T, which folded into an antiparallel G-quadruplex with higher targeting affinity. A stable APT1M6T-CTGF complex model was established by molecular simulation, which helped elucidate the molecular recognition mechanism of APT1M6T and CTGF and also provided experimental guidance for rational site-directed modification of APT1M6T. A locked nucleic acid sequence was then integrated into APT1M6T to generate APT1M6TL, which had higher structural stability. A BLI-based enzyme-linked aptamer sandwich assay (BLI-ELASA) was successfully developed. The method exhibited a broad detection range from 0.05 to 50 nM with a low detection limit of 0.02 nM. The method showed high selectivity, reproducibility, and stability for analysis of CTGF in spiked serum and urine samples. This developed BLI-ELASA is promising and enables real-time, sensitive and rapid detection of the disease-specific biomarker CTGF.

Dexamethasone mediates pancreatic cancer progression by glucocorticoid receptor, TGFβ and JNK/AP-1

Glucocorticoids such as dexamethasone are widely co-prescribed with cytotoxic therapy because of their proapoptotic effects in lymphoid cancer, reduction of inflammation and edema and additional benefits. Concerns about glucocorticoid-induced therapy resistance, enhanced metastasis and reduced survival of patients are largely not considered. We analyzed dexamethasone-induced tumor progression in three established and one primary human pancreatic ductal adenocarcinoma (PDA) cell lines and in PDA tissue from patients and xenografts by FACS and western blot analysis, immunohistochemistry, MTT and wound assay, colony and spheroid formation, EMSA and in vivo tumor growth and metastasis of tumor xenografts on chicken eggs and mice. Dexamethasone in concentrations observed in plasma of patients favored epithelial–mesenchymal transition, self-renewal potential and cancer progression. Ras/JNK signaling, enhanced expression of TGFβ, vimentin, Notch-1 and SOX-2 and the inhibition of E-cadherin occurred. This was confirmed in patient and xenograft tissue, where dexamethasone induced tumor proliferation, gemcitabine resistance and metastasis. Inhibition of each TGFβ receptor-I, glucocorticoid receptor or JNK signaling partially reversed the dexamethasone-mediated effects, suggesting a complex signaling network. These data reveal that dexamethasone mediates progression by membrane effects and binding to glucocorticoid receptor.

Rapid hepatic clearance of full length CCN-2/CTGF: a putative role for LRP1-mediated endocytosis

CCN-2 (connective tissue growth factor; CTGF) is a key factor in fibrosis. Plasma CCN-2 has biomarker potential in numerous fibrotic disorders, but it is unknown which pathophysiological factors determine plasma CCN-2 levels. The proteolytic amino-terminal fragment of CCN-2 is primarily eliminated by the kidney. Here, we investigated elimination and distribution profiles of full length CCN-2 by intravenous administration of recombinant CCN-2 to rodents. After bolus injection in mice, we observed a large initial distribution volume (454 mL/kg) and a fast initial clearance (120 mL/kg/min). Immunosorbent assay and immunostaining showed that CCN-2 distributed mainly to the liver and was taken up by hepatocytes. Steady state clearance in rats, determined by continuous infusion of CCN-2, was fast (45 mL/kg/min). Renal CCN-2 clearance, determined by arterial and renal vein sampling, accounted for only 12 % of total clearance. Co-infusion of CCN-2 with receptor-associated protein (RAP), an antagonist of LDL-receptor family proteins, showed that RAP prolonged CCN-2 half-life and completely prevented CCN-2 internalization by hepatocytes. This suggests that hepatic uptake of CCN-2 is mediated by a RAP-sensitive mechanism most likely involving LRP1, a member of the LDL-receptor family involved in hepatic clearance of various plasma proteins. Surface plasmon resonance binding studies confirmed that CCN-2 is an LRP1 ligand. Co-infusion of CCN-2 with an excess of the heparan sulphate-binding protamine lowered the large initial distribution volume of CCN-2 by 88 % and reduced interstitial staining of CCN-2, suggesting binding of CCN-2 to heparan sulphate proteoglycans (HSPGs). Protamine did not affect clearance rate, indicating that RAP-sensitive clearance of CCN-2 is HSPG independent. In conclusion, unlike its amino-terminal fragment which is cleared by the kidney, full length CCN-2 is primarily eliminated by the liver via a fast RAP-sensitive, probably LRP1-dependent pathway.

CCN: core regulatory proteins in the microenvironment that affect the metastasis of hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) results from an underlying chronic liver inflammatory disease, such as chronic hepatitis B or C virus infections, and the general prognosis of patients with HCC still remains extremely dismal because of the high frequency of HCC metastases. Throughout the process of tumor metastasis, tumor cells constantly communicate with the surrounding microenvironment and improve their malignant phenotype. Therefore, there is a strong rationale for targeting the tumor microenvironment as primary treatment of HCC therapies. Recently, CCN family proteins have emerged as localized multitasking signal integrators in the inflammatory microenvironment. In this review, we summarize the current knowledge of CCN family proteins in inflammation and the tumor. We also propose that the CCN family proteins may play a central role in signaling the tumor microenvironment and regulating the metastasis of HCC.

Serum Markers of Epithelial Mesenchymal Transition as Predictors of HCV-induced Liver Fibrosis, Cirrhosis and Hepatocellular Carcinoma

Introduction

Hepatitis C virus (HCV) is a major cause of chronic liver disease in Egypt, leading to hepatic fibrosis, liver cirrhosis (LC), and hepatocellular carcinoma (HCC). Liver fibrosis is characterized by excessive deposition of extracellular matrix (ECM). Newly-recognized pathogenic mechanisms point to the epithelial-mesenchymal transition (EMT) of hepatocytes to matrix synthesizing (myo-) fibroblasts. Transforming growth factor-beta (TGF-β1), bone morphogenic protein (BMP)-7, and connective tissue growth factor (CTGF) are biomarkers reflecting the EMT process. YKL-40 is a glycoprotein member of ECM and plays a role in cancer cell proliferation. The purpose of this study was to determine the serum biomarkers of EMT and its impact on the fibrogenic process and tumorigenesis in HCV-genotype 4 patients.

Methods

In this case-control study that was conducted in 2013–2014, 97 HCV-infected patients were subjected to clinical examination, laboratory investigations, and liver biopsy. According to the histopathologic examination, they were classified to F0 (14 cases), F1 (17 cases), F2 (15 cases), F3 (18 cases), F4 (22 cases), and HCC (11 cases). Fifteen age- and gender-matched subjects were included as normal controls. Serum levels of TGF-β1, BMP-7, CTGF, YKL-40 were assessed, and the TGF-β1/BMP-7 ratios were calculated. The data were analyzed by plotting the receiver operating characteristic curve (ROC), Pearson product-moment correlation coefficient, and Spearman’s rank correlation coefficient (Spearman’s rho).

Results

Serum levels of TGF-β1, BMP-7, CTGF, and YKL-40 were significantly increased in all patient groups compared to controls (p < 0.001). LC exhibited the highest CTGF level and YKL-40 was highest in HCC. The TGF-β1/ BMP-7 ratios reflected the progression of EMT from CHC to LC, however, there was no significant difference between LC and HCC. TGF-β1/ BMP-7 ratio is considered to reflect positive correlation with CTGF in LC group (r = 0.629; p < 0.03) and YKL-40 in HCC group (r = 0.504; p < 0.04).

Conclusion

Increased TGF-β1/BMP-7 ratio and CTGF levels reflect the rate of EMT and provide information about fibrogenic activity. Also, this ratio, in association with YKL-40, can be used to predict malignant transformation in HCV-genotype 4 Egyptian patients.

Pathobiochemical signatures of cholestatic liver disease in bile duct ligated mice

Background

Disrupted bile secretion leads to liver damage characterized by inflammation, fibrosis, eventually cirrhosis, and hepatocellular cancer. As obstructive cholestasis often progresses insidiously, markers for the diagnosis and staging of the disease are urgently needed. To this end, we compiled a comprehensive data set of serum markers, histological parameters and transcript profiles at 8 time points of disease progression after bile duct ligation (BDL) in mice, aiming at identifying a set of parameters that could be used as robust biomarkers for transition of different disease progression phases.

Results

Statistical analysis of the more than 6,000 data points revealed distinct temporal phases of disease. Time course correlation analysis of biochemical, histochemical and mRNA transcript parameters (=factors) defined 6 clusters for different phases of disease progression. The number of CTGF-positive cells provided the most reliable overall measure for disease progression at histological level, bilirubin at biochemical level, and metalloproteinase inhibitor 1 (Timp1) at transcript level. Prominent molecular events exhibited by strong transcript peaks are found for the transcriptional regulator Nr0b2 (Shp) and 1,25-dihydroxyvitamin D(3) 24-hydroxylase (Cyp24a1) at 6 h. Based on these clusters, we constructed a decision tree of factor combinations potentially useful as markers for different time intervals of disease progression. Best prediction for onset of disease is achieved by fibronectin (Fn1), for early disease phase by Cytochrome P450 1A2 (Cyp1a2), passage to perpetuation phase by collagen1α-1 (Col1a1), and transition to the progression phase by interleukin 17-a (Il17a), with early and late progression separated by Col1a1. Notably, these predictions remained stable even for randomly chosen small sub-sets of factors selected from the clusters.

Conclusion

Our detailed time-resolved explorative study of liver homogenates following BDL revealed a well-coordinated response, resulting in disease phase dependent parameter modulations at morphological, biochemical, metabolic and gene expression levels. Interestingly, a small set of selected parameters can be used as diagnostic markers to predict disease stages in mice with cholestatic liver disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-015-0229-0) contains supplementary material, which is available to authorized users.

Evaluating Serum Markers for Hormone Receptor-Negative Breast Cancer

INTRODUCTION

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death in females worldwide. Death rates have been declining, largely as a result of early detection through mammography and improved treatment, but mammographic screening is controversial because of over-diagnosis of breast disease that might not require treatment, and under-diagnosis of cancer in women with dense breasts. Breast cancer screening could be improved by pairing mammography with a tumor circulating marker, of which there are currently none. Given genomic similarities between the basal breast cancer subtype and serous ovarian cancer, and given our success in identifying circulating markers for ovarian cancer, we investigated the performance in hormone receptor-negative breast cancer detection of both previously identified ovarian serum markers and circulating markers associated with transcripts that were differentially expressed in breast cancer tissue compared to healthy breast tissue from reduction mammaplasties.

METHODS

We evaluated a total of 15 analytes (13 proteins, 1 miRNA, 1 autoantibody) in sera drawn at or before breast cancer surgery from 43 breast cancer cases (28 triple-negative-TN-and 15 hormone receptor-negative-HRN-/ HER2-positive) and 87 matched controls.

RESULTS

In the analysis of our whole cohort of breast cancer cases, autoantibodies to TP53 performed significantly better than the other selected 14 analytes showing 25.6% and 34.9% sensitivity at 95% and 90% specificity respectively with AUC: 0.7 (p<0.001). The subset of 28 TN cancers showed very similar results. We observed no correlation between anti-TP53 and the 14 other markers; however, anti-TP53 expression correlated with Body-Mass-Index. It did not correlate with tumor size, positive lymph nodes, tumor stage, the presence of metastases or recurrence.

CONCLUSION

None of the 13 serum proteins nor miRNA 135b identified women with HRN or TN breast cancer. TP53 autoantibodies identified women with HRN breast cancer and may have potential for early detection, confirming earlier reports. TP53 autoantibodies are long lasting in serum but may be affected by storage duration. Autoantibodies to TP53 might correlate with Body-Mass-Index.

Targeting the tumor stroma in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and deadly cancers worldwide. In ninety percent of the cases it develops as a result of chronic liver damage and it is thus a typical inflammation-related cancer characterized by the close relation between the tumor microenvironment and tumor cells. The stromal environment consists out of several cell types, including hepatic stellate cells, macrophages and endothelial cells. They are not just active bystanders in the pathogenesis of HCC, but play an important and active role in tumor initiation, progression and metastasis. Furthermore, the tumor itself influences these cells to create a background that is beneficial for sustaining tumor growth. One of the key players is the hepatic stellate cell, which is activated during liver damage and differentiates towards a myofibroblast-like cell. Activated stellate cells are responsible for the deposition of extracellular matrix, increase the production of angiogenic factors and stimulate the recruitment of macrophages. The increase of angiogenic factors (which are secreted by macrophages, tumor cells and activated stellate cells) will induce the formation of new blood vessels, thereby supplying the tumor with more oxygen and nutrients, thus supporting tumor growth and offering a passageway in the circulatory system. In addition, the secretion of chemokines by the tumor cells leads to the recruitment of tumor associated macrophages. These tumor associated macrophages are key actors of cancer-related inflammation, being the main type of inflammatory cells infiltrating the tumor environment and exerting a tumor promoting effect by secreting growth factors, stimulating angiogenesis and influencing the activation of stellate cells. This complex interplay between the several cell types involved in liver cancer emphasizes the need for targeting the tumor stroma in HCC patients.

In vitro selection and characterization of deoxyribonucleic acid aptamers against connective tissue growth factor

Connective tissue growth factor (CTGF) is a secreted matricellular protein possessing complex biological functions. CTGF modulates a number of signaling pathways that are involved in cell adhesion, migration, angiogenesis, myofibroblast activation, extracellular matrix deposition and tissue remodeling. Aptamers are oligonucleic acid chains or polypeptides that bind with specific target molecules hence have the potential to be used in the detection and blockade of the targets. In this study, we selected CTGF-targeting DNA aptamers by using systematic evolution of ligands by exponential enrichment (SELEX). After 8 iterative rounds of selection, cloning, DNA sequencing and affinity determination, six aptamers with high affinities to CTGF were obtained. Among them, one (C-ap17P) binds with the N-terminal region (aa 1-190) and the other five (C-ap11, 12, 14, 15 and 18) bind with the C-terminal region (aa 191-350) of hCTGF specifically. The biological stability assay indicated that a representative aptamer, C-ap17P, could keep its integrity at a rather high level for at least 24 h in complete DMEM cell culture medium. These CTGF aptamers might be used as a easy and fast detection tool for CTGF and be developed as CTGF-specific inhibitors for both research works and clinical applications.

Expression of CCN family members correlates with the clinical features of hepatocellular carcinoma

Studies have reported that the CCN family of proteins plays an important role in stimulating tumorigenesis. However, the relationship between the CCN protein family members and the features of hepatocellular carcinoma (HCC) remains unclear. The objective of this study was to determine the relationship between the expression levels of CCN protein family members and the features of HCC. Expression levels of the CCN family of proteins in 80-paired primary HCC samples and 11 normal liver samples were determined by a quantitative real-time PCR assay. Enhanced expression of nephroblastoma overexpressed protein (NOV) and decreased expression of Wnt-induced secreted protein 1 (WISP1), cysteine-rich protein 61 (CYR61) and connective tissue growth factor (CTGF) were found in HCC samples when compared to levels in matched non-cancerous tissues. No significant difference in WISP2 was found between matched-pair samples; only a few samples showed WISP3 expression. Furthermore, the expression levels of NOV, WISP1 and CYR61 were closely correlated with certain clinical features, including venous invasion, cellular differentiation, pTNM stage, disease-free survival and overall survival. Our results suggest that HCC progression may be enhanced by NOV and suppressed by WISP1 and CYR61. Our statistical analysis suggests that these proteins may be valuable in determining the prognosis of this deadly disease and directs attention to modulating the levels of these proteins as a potential mode of therapy.

Gene expression profiling of bovine mammary gland epithelial cells stimulated with lipoteichoic acid plus peptidoglycan from Staphylococcus aureus

A Gram-positive bacterium, Staphylococcus aureus is known to be one of the major pathogenic bacteria responsible for causing bovine mastitis. Among the various cell wall components of S. aureus, lipoteichoic acid (LTA) and peptidoglycan (PGN) are closely associated with inflammatory responses. However, the role of LTA and PGN derived from S. aureus in bovine mastitis has not been clearly elucidated. In this study, we characterized the gene expression profile of a bovine mammary gland epithelial cell line, MAC-T cells, in the presence of LTA and PGN from S. aureus. LTA plus PGN, but not LTA or PGN alone, activated MAC-T cells. The analysis of transcriptional profiles using an Affymetrix genechip microarray showed that stimulation with LTA plus PGN produced a total of 2019 (fold change >1.2) differentially expressed genes (DEGs), with 801 up-regulated genes and 1218 down-regulated genes. Of the up-regulated genes, 14 inflammatory mediator-related DEGs, 22 intra-cellular signaling molecule-related DEGs, and 15 transcription factor-related DEGs were observed, whereas among the down-regulated DEGs 17 inflammation-related DEGs were found. The microarray results were confirmed using real-time RT-PCR of 18 genes with substantial changes in expression (9 each from the up-regulated and down-regulated DEGs). These results provide a comprehensive analysis of gene-expression profiles elicited by S. aureus LTA and PGN in MAC-T cells, contributing to an understanding of the pathogenesis for S. aureus-induced bovine mastitis.

Monitoring fibrogenic progression in the liver

The clinical course of chronic liver diseases is significantly dependent on the progression rate of fibrosis which is the unstructured replacement of injured parenchyma by extracellular matrix. Despite intensive studies, the clinical opportunities for patients with fibrosing liver diseases have not improved. This will be changed by increasing knowledge of new pathogenetic mechanisms, which complement the "canonical principle" of fibrogenesis. The latter is based on the activation of hepatic stellate cells and their transdifferentiation to myofibroblasts induced by hepatocellular injury and consecutive inflammatory mediators such as TGF-β. Stellate cells express a broad spectrum of matrix components. New mechanisms indicate that the heterogeneous pool of (myo-)fibroblasts can be supplemented by epithelial-mesenchymal transition (EMT) from cholangiocytes and potentially also from hepatocytes to fibroblasts, by influx of bone marrow-derived fibrocytes in the damaged liver tissue and by differentiation of a subgroup of monocytes to fibroblasts after homing in the damaged tissue. These processes are regulated by the cytokines TGF-β and BMP-7, chemokines, colony-stimulating factors, metalloproteinases and numerous trapping proteins. They offer innovative diagnostic and therapeutic options. As an example, modulation of TGF-β/BMP-7 ratio changes the rate of EMT, and so the simultaneous determination of these parameters and of the connective tissue growth factor (CTGF) in serum might provide information on fibrogenic activity. Also, proteomic and glycomic approaches of serum are under investigation to set up specific protein profiles in patients with liver fibrosis. The aim of this article is to present the current pathogenetic concepts of liver fibrosis and to discuss established and novel diagnostic approaches to reflect the process of hepatic fibrogenesis in the medical laboratory.

PKCδ as a regulator for TGF-β-stimulated connective tissue growth factor production in human hepatocarcinoma (HepG2) cells

CTGF (connective tissue growth factor) is widely regarded as an important amplifier of the profibrogenic action of TGF-β (transforming growth factor β) in a variety of tissues, although the precise mechanism of how the TGF-β signalling pathways modulate CTGF expression remains unclear. In the present study, the role of PKCδ (protein kinase Cδ) in TGF-β1-mediated CTGF expression was investigated using HepG2 cells. TGF-β1 treatment specifically elevated PKCδ activation and CTGF expression. In contrast, blockade of PKCδ by the selective inhibitor Rottlerin or by siRNA knockdown significantly reduced TGF-β1-induced CTGF production. The regulatory mechanism was further demonstrated in HepG2 cells whereby TGF-β1-induced PKCδ activation negatively regulated the nuclear levels of PPM1A (protein phosphatase, Mg2+/Mn2+ dependent, 1A) through the RhoA/ROCK (Rho-associated kinase) pathway. Moreover, we showed that both Smad signalling and the PKCδ pathway appeared to be stimulated by TGF-β1 in parallel. Time course assessments indicated that PKCδ signalling may have a function in maintaining nuclear phospho-Smads at a maximal level. The collective results of the present study demonstrated that PKCδ-stimulated RhoA/ROCK activation resulted in a reduction in PPM1A, thereby up-regulating Smad-dependent gene induction for extended periods. These findings indicated that PKCδ plays a critical role in TGF-β1-induced CTGF production in HepG2 cells.