• IMMUNE NETWORK
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• v.9 no.4
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• pp.133-137
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• 2009

We have recently shown that activin A, a member of TGF-$\beta$ superfamily, stimulates mouse B cells to express IgA isotype but other isotypes. In the present study, we further characterized effects of activin A on B cell growth and IgA expression. We found that activin A did not have effect on LPS-stimulated cell viability. In parallel, CFSE staining analysis revealed that activin A did not alter cell division. An increase of IgA secretion by activin A was completely abrogated by anti-activin A Ab but not by anti-TGF$\beta$1 Ab. In the same conditions, no other isotypes are significantly affected by each antibody treatment. Finally, activin A, as similar to TGF-$\beta$1, increased IgA secretion by mesenteric lymph node cells. These results suggest that activin A can specifically stimulate IgA response, independent of TGF-$\beta$ in the gut.

• Journal of Life Science
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• v.9 no.5
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• pp.504-509
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• 1999

The trend of organogenesis in Xenopus presumptive ectoderm was studied by combined dose of activin A and IGF-1(insulin-like growth factor-1). In reference study of Asashima and his colleagues, the inductive patterns of various organs were reported with activin, the potent mesoderm inducing factor. In present study, the inducing pattern was cleared with combined-dose of concentration 1-100 ng/ml activin A and IGF-1. In addition, the result from single treatment of activin A was compared with former study. As a result, eye was differentiated in 5-20% of explants at 10 and 50 ng/ml concentrative combination of activin A. Otic vesicle was appeared in the entire concentrative combination of IGF-1. Pronephric duct was induced 19-38% of explants at the concentration of activin A 100 ng/ml by adding IGF-1. The comparison of single treatment of activin A was showed some difference in dose-dependent inducing pattern.

• IMMUNE NETWORK
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• v.11 no.4
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• pp.196-202
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• 2011

Background: B cell-activating factor belonging to the TNF family (BAFF) is primarily expressed by macrophages and dendritic cells, and stimulates B cell proliferation, differentiation, survival, and Ig production. In the present study, we explored the effect of activin A on BAFF expression by APCs. Methods: To investigate the effect of activin A on BAFF expression by mouse APCs, we measured the level of BAFF expression at the transcriptional and protein levels using RT-PCR and ELISA. Results: Activin A markedly enhanced BAFF expression in mouse macrophages and dendritic cells at both the transcriptional and protein levels. SB431542, an activin receptor-like kinase 4 (ALK4) inhibitor, completely abrogated activin A-induced BAFF transcription. Furthermore, overexpression of DN-Smad3 abolished activin-induced BAFF expression at the transcriptional and protein levels. Conclusion: These results demonstrate that activin A can enhance BAFF expression through ALK4-Smad3 pathway.

• Journal of Life Science
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• v.8 no.5
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• pp.479-485
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• 1998

The induction of nephric duct from Xenopus presumptive ectoderm(animal cap) was studied and the high-dose ef-fect of IGF-1 was investigated. Activin A induce various organs from cultured animal cap explants and the effects are time and dose-dependent. On the induction of nephric duct, the combined-dose of activin A and retinoic acid was very efficient method in reference study. In present study, we used IGF-1 as well as activin A as a combined growth factor. The concentration ranges of growth factors were activin A l00ng/ml an IGF-1 0-500ng/m1. Explants were cultured in combined solution for 3days to the normal embryo arrives at st. 43. In general, when the explant was cultured in high concentration(l00ng/ml) of activin A, it was destroyed, however, nephric duct and other tis-sues were differentiated by adding IGF-1. In addition, eye induction by adding IGF-1 500ng/ml to activin A 1- 100 ng/ml solution was studied. The low concentration of activin A(1ng/ml) have blood-like cell inducing effect and the explant was balloon-shaped, however, the high dose combination with IGF-1 extended the range of eye inductive concentration of activin A.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.204-210
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• 1999

The present studies were conducted to evaluate the effects of activin-A on gonadotropins (GTHs) release in testosterone-treated immature rainbow trout Oncorhpynchus mykiss. The administration of testosterone elevated pituitary level of GTH II but not of GTH I. In this study using primary cultures of dispersed pituitary cells in static incubation, dose-dependent increases in GTH II release was observed in the activin-treated group at day 3 of incubation (long-term incubation), but not at day 1 of incubation (short-term incubation). Dopamine, a potent inhibitor of gonadotropin-releasing hormone (GnRH)-stimulated GTH II release in rainbow trout, was only partially effective in decreasing actvin-induced GTH II release. Furthermore, salmon GnRH (sGnRH)-stimulated GTH II release was not potentiated by the pretreatment with activin. However, the control mechanisms of GTH I release by activin and other hormones were not observed in the all tested experiments. The results of these studies support the contention that in contrast with the usual stimulatory effects of activin on GTH release in mammals, activin exerts long-term stimulatory actions on GTH II release in rainbow trout. The control mechanism of GTH I release, however, is a question that remains to be elucidated.

• Molecules and Cells
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• v.38 no.12
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• pp.1079-1085
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• 2015

Originally, activins were identified as stimulators of FSH release in reproduction. Other activities, including secondary axis formation in development, have since been revealed. Here, we investigated the influence of activin ${\beta}_A$ on the body, including the gastro-intestinal (GI) tract. Initially, the activin ${\beta}_A$ protein was detected in the serum proportional to the amount of pCMV-rAct plasmid injected. The induced level of activin ${\beta}_A$ in muscle was higher in female than male mice. Subsequent results revealed that stomach and intestine were severely damaged in pCMV-rAct-injected mice. At the cellular level, loss of parietal cells was observed, resulting in increased pH within the stomach. This phenomenon was more severe in male than female mice. Consistent with damage of the stomach and intestine, activin ${\beta}_A$ often led to necrosis in the tip of the tail or foot, and loss of body weight was observed in pCMV-rAct-injected male but not female mice. Finally, in pCMV-rAct-injected mice, circulating activin ${\beta}_A$ led to death at supraphysiological doses, and this was dependent on the strain of mice used. Taken together, these results indicate that activin ${\beta}_A$ has an important role outside of reproduction and development, specifically in digestion. These data also indicate that activin ${\beta}_A$ must be controlled within a narrow range because of latent lethal activity. In addition, our approach can be used effectively for functional analysis of secreted proteins.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8581-8586
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• 2014

Activin is a multifunctional growth and differentiation factor of the growth factor-beta (TGF-${\beta}$) superfamily, which inhibits the proliferation of colon cancer cells. It induces phosphorylation of intracellular signaling molecules (Smads) by interacting with its type I and type II receptors. Previous studies showed that human activin receptor-interacting protein 2 (hARIP2) can reduce activin signaling by interacting with activin type II receptors; however, the activity of hARIP2 in colon cancer has yet to be detailed. In vitro, overexpression of hARIP2 reduced activin-induced transcriptional activity and enhanced cell proliferation and colony formation in human colon cancer HCT8 cells and SW620 cells. Also, hARIP2 promoted colon cancer cell apoptosis, suggesting that a vital role in the initial stage of colon carcinogenesis. In vivo, immunohistochemistry revealed that hARIP2 was expressed more frequently and much more intensely in malignant colon tissues than in controls. These results indicate that hARIP2 is involved in human colon tumorigenesis and could be a predictive maker for colon carcinoma aggressiveness.

• BMB Reports
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• v.51 no.12
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• pp.636-641
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• 2018

DPP4 (dipeptidyl peptidase-4), a highly conserved transmembrane glycoprotein with an exo-peptidase activity, has been shown to contribute to glucose metabolism, immune regulation, signal transduction, and cell differentiation. Here, we show that DPP4 is involved in control of activin/nodal signaling in Xenopus early development. In support of this, gain of function of DPP4 augmented Smad2 phosphorylation as well as expression of target genes induced by activin or nodal signal. In addition, Dpp4 and Xnr1 showed synergistic effect on induction of ectopic dorsal body axis, when co-injected at suboptimal doses in early embryos. Conversely, saxagliptin, a DPP4 inhibitor repressed activin induction of Smad2 phosphorylation. Notably, overexpression of Dpp4 disrupted specification of dorsal body axis of embryo, leading to malformed phenotypes such as spina bifida and a shortened and dorsally bent axis. Together, these results suggest that DPP4 functions as a potentiator of activin/nodal signaling pathway.

• Reproductive and Developmental Biology
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• v.34 no.3
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• pp.135-141
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• 2010

Embryoid bodies (EBs) generated from human embryonic stem cells (hESCs) include spontaneously induced endodermal lineage cells (ELCs). Activin-A plays important roles in the endoderm differentiation of hESCs. Despite studies on the generation of ELCs from hESCs with treatment of Actvin-A, it was unclear for localization and pattern of ELCs by Activin-A during differentiation of hESCs. Accordingly in this study, we knew that Actvin-A increased the cystic EBs formation, including the highly enriched AFP (endoderm lineage specific marker)-expressing cells in the surface of cystic EBs. To induce the EBs formation from undifferentiated hESCs, cells were transferred onto petri-dish and cultured in suspension condition without bFGF removed hESC media (EB media) for 3 days. Next to investigate the effect of Activin-A, EBs were subsequently cultured in EB media supplement with 100 ng/ml Activin-A for 3 days. After 5~7 days of Activin-A treatment, cystic EBs began to appear which increased in numbers reaching ~60% of initially formed EBs over 5 days. Endoderm lineage marker, AFP were highly expressed and specifically localized at the surface region of cystic EBs comparison with normal EBs. We next attached the cystic EBs onto gelatin-coated plates and cultured for 5 days. In the results of real-time PCR and immunocytochemistry analysis, AFP-expressing cells migrated and localized at the outgrowth region of attached cystic EBs. To obtain the AFP-expressing cells of the outgrowth region, we manually isolated by using micro-dissection and cultured them. These cells strongly express AFP over 70% of isolated cells post re-plating. Here, we first showed an expression pattern of specifically localized ELCs by Activin-A during differentiation of hESCs. From this observation, we could highly purified ELCs from undifferentiated hESCs. Taken together, our system will provide a novel and efficient option to generate ELCs from hESCs.

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.127-132
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• 2014

This study was carried out to investigate the effects of tissue inhibitor of matalloproteinase-1 (TIMP-1), Activin A and Heparin binding epidermal growth factor (HB-EGF) on in vitro production of bovine embryos. In experiment 1, presumptive zygotes were cultured in the medium supplemented with TIMP-1 ($0.5{\mu}g/ml$), Activin A (100 ng/ml), or HB-EGF (100 ng/ml) at $39^{\circ}C$ in a humidified atmosphere of 5% (v/v) $CO_2$, 5% (v/v) $O_2$ and 90% (v/v) $N_2$. In experiment 2, TIMP-1 + HB-EGF or Activin A + HB-EGF combinations were supplemented in the culture medium. The developmental rate to blastocysts, hatching rate and total cell numbers of the blastocysts were evaluated in both experiments. The embryos cultured in medium without growth factor supplementation was used as control group. In experiment 1, the embryos cultured in medium supplemented with TIMP-1 and Activin A showed significantly higher developmental rate to blastocysts than those cultured with HB-EGF and control (36.9%, 34.1%, 21.2% and 23.1%, respectively) (P<0.0001). However, the hatching rate of blastocyst was significantly higher in embryos with HB-EGF than those with TIMP-1, Actvin A and Control groups (84.4%, 58.8%, 51.4% and 49.3%, respectively) (P<0.001). Total cell number per blastocyst was also significantly higher in embryos with HB-EGF group ($174.3{\pm}2.5$) than those with TIMP-1, Activin A (149.7 and 150.0, respectively) (P<0.05) and Control (119.0) (P<0.001). In experiment 2, embryos cultured with combined treatment of Activin A and HB-EGF resulted in significantly higher rates of blastocysts formation (48.0%), hatching rate (89.7%) and total cell number in blastocyst ($182.3{\pm}2.1$) than those with TIMP-1 and HB-EGF combination group (32.0%, P<0.001; 76.6%, P<0.05; $165.7{\pm}4.2$, P<0.001, respectively). Our data demonstrate that in vitro production of bovine embryos could be improved by combined supplementation of Activin A and HB-EGF in culture medium.