Activins and Follistatin in Chronic Hepatitis C and Its Treatment with Pegylated-Interferon-α Based Therapy

Downregulation of activin-signaling gene expression in passaged normal human dermal fibroblasts

Activins are members of the transforming growth factor-β (TGF-β) superfamily and play important roles in proliferation, differentiation, and apoptosis of various target cells. We investigated changes of activin, activin receptor (ActR), and Smad-signaling gene expression with increasing passage number in normal human dermal fibroblasts. The expression of mRNA and protein was measured by reverse transcription-quantitative polymerase chain reaction and immunoblot analysis from passage numbers 5 to 15. Activin A and follistatin transcript levels increased with increasing passage number. ActR types IA, IB, IIA and IIB mRNA levels decreased at high passage number. The levels of Smad2, 3 and 4 protein decreased with increasing passage number, which also attenuated phosphorylation of Smad2 and 3 protein expression. Smad7 was enhanced with increasing passage number. These results suggest that expression of activin-signaling in aging normal human dermal fibroblasts increases activin A and follistatin, whereas ActR-Smad signaling is decreased.

Activin Biology After Lung Transplantation

BACKGROUND

Activins A and B, members of the TGF-β superfamily, are produced as part of the physiological response to tissue damage and the resulting proinflammatory response. Given that lung allograft reperfusion results in an inflammatory response, it is likely that the activins and their binding protein follistatin will form part of the regulatory response. There is a need to document the response of these proteins to allograft reperfusion to determine if there is a role for the use of follistatin to control the biological actions of the activins because some of these are potentially damaging.

METHODS

Serum from 48 consecutive patients undergoing lung transplantation (LTx) was collected at 2, 6, 12, and 26 weeks post-LTx. The serum levels of activin A and B and follistatin were measured by enzyme-linked immunosorbent assay and specific radioimmunoassays and compared with clinical events.

RESULTS

Serum activin A and B levels were at the upper limit of the normal ranges at 2 weeks post-LTx decreasing thereafter to 12 weeks post-LTx (P < 0.05). In contrast, serum follistatin levels were unchanged between 2 and 12 weeks, with a late significant increase at 24 week post-LTx (P < 0.01). Patients with primary graft dysfunction had lower serum follistatin levels (7.7 vs 9.5 ng/mL; P = 0.04) and a higher activin A/follistatin ratio (13.1 vs 10.4; P = 0.02) at 2 weeks post-LTx.

CONCLUSIONS

Activin and follistatin levels vary with time form LTX and reflect a proinflammatory environment. Future studies will elucidate associations with chronic lung allograft dysfunction and the therapeutic potential of exogenous follistatin administration.

Activins and their related proteins in colon carcinogenesis: insights from early and advanced azoxymethane rat models of colon cancer

Background

Activin-A may exert pro- or anti-tumorigenic activities depending on cellular context. However, little is known about its role, or the other mature activin proteins, in colorectal carcinoma (CRC). This study measured the expression of activin βA- & βB-subunits, activin type IIA & IIB receptors, smads 2/3/4/6/7 and follistatin in CRC induced by azoxymethane (AOM) in rats. The results were compared with controls and disseminated according to the characteristics of histopathological lesions.

Methods

Eighty male Wistar rats were allocated into 20 controls and the remaining were equally divided between short ‘S-AOM’ (15 weeks) and long ‘L-AOM’ (35 weeks) groups following injecting AOM for 2 weeks. Subsequent to gross and histopathological examinations and digital image analysis, the expression of all molecules was measured by immunohistochemistry and quantitative RT-PCR. Activin-A, activin-B, activin-AB and follistatin were measured by ELISA in serum and colon tissue homogenates.

Results

Colonic pre-neoplastic and cancerous lesions were identified in both AOM groups and their numbers and sizes were significantly (P < 0.05) greater in the L-AOM group. All the molecules were expressed in normal colonic epithelial cells. There was a significantly (P < 0.05) greater expression of βA-subunit, IIB receptor and follistatin in both pre-neoplastic and cancerous tissues. Oppositely, a significant (P < 0.05) decrease in the remaining molecules was detected in both AOM groups. Metastatic lesions were only observed within the L-AOM group and were associated with the most significant alterations of all molecules. Significantly higher concentrations of activin-A and follistatin and lower activin-AB were also detected in both groups of AOM. Tissue and serum concentrations of activin-A and follistatin correlated positively, while tissue activin-AB inversely, and significantly with the numbers and sizes of colonic lesions.

Conclusions

Normal rat colon epithelial cells are capable of synthesising, controlling as well as responding to activins in a paracrine/autocrine manner. Colonic activin systems are pathologically altered during tumorigenesis and appear to be time and lesion-dependent. Activins could also be potential sensitive markers and/or molecular targets for the diagnosis and/or treatment of CRC. Further studies are required to illustrate the clinical value of activins and their related proteins in colon cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2914-9) contains supplementary material, which is available to authorized users.

Serum Levels of Follistatin Are Positively Associated With Serum-Free Thyroxine Levels in Patients With Hyperthyroidism or Euthyroidism

Follistatin is a glycoprotein with various biologic functions that plays a role in adipocyte differentiation, muscle stimulation, anti-inflammation, and energy homeostasis. Thyroid hormones influence energy expenditure, glucose, and lipid metabolism. The association between serum follistatin level and thyroid function statuses has seldom been evaluated.The objectives of this study were to compare serum follistatin concentrations in different thyroid function statuses and to evaluate the associations between serum follistatin and free thyroxine (fT4) levels.In this study, 30 patients with hyperthyroidism (HY group) and 30 euthyroid individuals (EU group) were recruited. The patients of HY group were treated with antithyroid regimens as clinically indicated, whereas no medication was given to EU group. The demographic and anthropometric characteristics, biochemical data, serum levels of follistatin, and thyroid function of both groups at baseline and at the 6th month were compared. Data of all patients were pooled for the analysis of the associations between the levels of follistatin and fT4.At baseline, the HY group had significantly higher serum follistatin levels than the EU group (median [Q1, Q3]: 1.81 [1.33, 2.78] vs 1.13 [0.39, 1.45] ng/mL, P < 0.001). When treated with antithyroid regimens, the follistatin serum levels in HY group decreased to 1.54 [1.00, 1.88] ng/mL at the 6th month. In all patients, the serum levels of follistatin were positively associated with fT4 levels at baseline (β = 0.54, P = 0.005) and at the 6th month (β = 0.59, P < 0.001). The association between follistatin and fT4 levels remained significant in the stepwise multivariate regression analysis, both initially and at the 6th month.In comparison to the EU group, patients with hyperthyroidism had higher serum follistatin levels, which decreased after receiving antithyroid treatment. In addition, the serum follistatin concentrations were positively associated with serum fT4 levels in patients with hyperthyroidism or euthyroidism.

Pegylated Interferon-α Modulates Liver Concentrations of Activin-A and Its Related Proteins in Normal Wistar Rat

Aims. To measure the expression of activin βA-subunit, activin IIA and IIB receptors, Smad4, Smad7, and follistatin in the liver and the liver and serum concentrations of mature activin-A and follistatin in normal rat following treatment with pegylated interferon-α (Peg-INF-α) and ribavirin (RBV). Materials and Methods. 40 male Wistar rats were divided equally into 4 groups: “control,” “Peg-only” receiving 4 injections of Peg-INF-α (6 µg/rat/week), “RBV-only” receiving ribavirin (4 mg/rat/day) orally, and “Peg & RBV” group receiving both drugs. The expression of candidate molecules in liver was measured by immunohistochemistry and quantitative PCR. The concentrations of mature proteins in serum and liver homogenate samples were measured using ELISA. Results. Peg-INF-α  ± RBV altered the expression of all candidate molecules in the liver at the gene and protein levels (P < 0.05) and decreased activin-A and increased follistatin in serum and liver homogenates compared with the other groups (P < 0.05). There were also significant correlations between serum and liver activin-A and follistatin. Conclusion. Peg-INF-α modulates the hepatic production of activin-A and follistatin, which can be detected in serum. Further studies are needed to explore the role of Peg-INF-α on the production of activins and follistatin by the liver and immune cells.

The effects of pegylated interferon-α and ribavirin on liver and serum concentrations of activin-A and follistatin in normal Wistar rat: a preliminary report

Background

Activin-A and follistatin regulate the liver and the immune system.

Aims

To measure the effects of treatment with pegylated-interferon-α (Peg-IFN-α) and ribavirin on the concentrations of mature activin-A and follistatin in serum and liver tissue homogenates in rats.

Methods

A total of 28 male Wistar rats were divided equally into four groups as follow: ‘Control group’ (n = 7), ‘PEG only group’ consisted of those that only received a weekly injection of Peg-IFN-α (6 µg/rat) for 4 weeks, ‘RBV only group’ received ribavirin only (4 mg/rat/day) orally for 35 days and the last group received both Peg-IFN-α and ribavirin ‘PEG & RBV group’. The concentrations of candidate proteins in serum and liver samples were measured using ELISA.

Results

Pegylated-interferon-α decreased activin-A and increased follistatin significantly in serum and liver of ‘PEG only’ and ‘PEG & RBV’ groups compared with the ‘Control’ and ‘RBV only’ groups (P < 0.05). There was no significant difference between the ‘RBV only’ and ‘Control’ groups (P > 0.05) in the concentrations of candidate proteins. A significant positive correlations between serum and liver activin-A (r = 0.727; P = 0.02 × 10⁻³) and follistatin (r = 0.540; P = 0.01) was also detected.

Conclusion

Pegylated-interferon-α modulates the production of activin-A and follistatin by the liver, which is reflected and can be detected at the serum level. Further studies are needed to explore the role of Peg-IFN-α based therapy on the production of activins and follistatin by the liver and immune cells.