• Biomedical Science Letters
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• v.26 no.4
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• pp.256-266
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• 2020

Carboxypeptidase D (CPD) is a zinc-dependent protease, which is highly expressed in macrophages, and is thought to participate in inflammatory processes. In the present study, we investigated the possible regulatory effect of all-trans retinoic acid (ATRA), which is an active form of vitamin A and plays a critical regulatory role in both the innate and adaptive immunity, on CPD expression and secretion in human monocytic THP-1 cells. CPD mRNA expression first increased, from a concentration as low as 10 nM ATRA to a maximum level of expression, at 1 μM. ATRA enhanced intracellular CPD expression in a time- and concentration-dependent manner but did not affect cell surface CPD expression. Interestingly, 9-cis-RA did not affect CPD expression. Additionally, an experiment with RAR/RXR selective agonist or antagonists demonstrated that ATRA-induced enhancement of CPD expression was RAR/RXR dependent. ATRA also enhanced CPD secretion from THP-1 cells; however, this enhancement was RAR/RXR-independent. The anti-inflammatory agent dexamethasone reversed ATRA-induced enhancement of CPD expression and secretion. Our results suggest ATRA exerts regulatory effects on expression and secretion of CPD in human monocytes, and ATRA-induced CPD secretion may be associated with inflammatory response.

• BMB Reports
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• v.36 no.4
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• pp.354-358
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• 2003

For better understanding of functions of the Calcyclin Binding Protein (CacyBP) and exploring its possible roles in neuronal differentiation, the subcellular localization of human CacyBP was examined in retinoic acid(RA)-induced and uninduced neuroblastoma SH-SY5Y cells. Immunostaining indicated that CacyBP was present in the cytoplasm of uninduced SH-SY5Y cells, in which the resting $Ca^{2+}$ concentration was relatively lower than that of RA-induced cells. After the RA induction, immunostaining was seen in both the nucleus and cytoplasm. In the RA-induced differentiated SH-SY5Y cells, CacyBP was phosphorylated on serine residue(s), while it existed in a dephosphorylated form in normal (uninduced) cells. Thus, the phosphorylation of CacyBP occurs when it is translocated to the nuclear region. The translocation of CacyBP during the RA-induced differentiation of SH-SY5Y cells suggested that this protein might play a role in neuronal differentiation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.198-198
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• 1998

Muc1 mucin is found in a variety of epithelial tissue and is overexpressed in several epithelial cancer. Recently it is alsol reported that primary Hamster tracheal surface epithelial(HTSE) cells express Muc1 protein and cDNA encoding HTSE muc1 protein has been cloned. Although numerous monoclonal antibodies (mAbs) to human muncins, particularly Muc1 have been produced, no such antibodies to murine Muc1 have been described. We now describe monoclonal antibody, called mAb M1CT, produced to C-terminal region of HTSE Muc1 protein by immunising mice with a glutathion-s-transferase linked fusion protein. In this study, using this antibody(mAb M1CT) we investigated the effect of RA on the expression of Muc1 in HTSE cells. Retinoic acid(RA) plays an essential role in maintaining normal differentiation of tracheal epithelial cells. With RA-deficiency tracheocytes undergo squamous metaplasia, an abnormal differentiation that can be reversed by RA. We had primary culture of HTSE cells under different concentrations of RA. Culture was maintained until the direction of differentiation was determined. Then Western blot analysis with mAb M1CT was performed with the cell lysates from the culture. The expression of Muc1 protein was decreased in dose-dependent manner as the concentration of retinoic acid was decreased. Our result indicates that the expression of Muc1 protein is coordinately regulated with airway mucous cell differentiation by RA pathway. And the antibody, mAb M1CT, produced in this study should provide useful tool to study the expression of Muc1 mucin in differentiation process or disease.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.533-540
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• 2000

Melanization of B16 melanoma cells was comparatively studied by the aqueous extract of Epimedium koreanum Nakai(EK) and $\alpha$-MSH. In addition, inhibitory effects of RA was investigated. B16 melanoma cells(about 1${\times}10_5$) have been shown an increase in tyrosinase activity and melanin contents in proportion to concentration of $\alpha$-MSH when treated with $\alpha$-MSH and incubated for 72 hrs. They indicated a 350% increase in tyrosinase activity and a 290% increase in melanin contents at 8 ng/mL. In case of EK, they have been shown a 200% increase in tyrosinase activity and a 180% increase in melanin contents at 100 ${\mu}g$/mL. In addition of RA to the above condition, they have been shown an inhibition from 350% to 210% in tyrosinase activity and from 290% to 250% in melanin contents in $\alpha$-MSH, and inhibition from 200% to 100% in tyrosinase activity and from 180% to 120% in melanin contents in EK. From the above results, it is suggested that EK promotes melanization of B16 melanoma cells through cAMP pathway, whereas RA inhibits it.

• International Journal of Stem Cells
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• v.15 no.3
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• pp.247-257
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• 2022

Background and Objectives: Although human-induced pluripotent stem cells (hiPSC) can be efficiently differentiated into cardiomyocytes (CMs), the heterogeneity of the hiPSC-CMs hampers their applications in research and regenerative medicine. Retinoic acid (RA)-mediated signaling pathway has been proved indispensable in cardiac development and differentiation of hiPSC toward atrial CMs. This study was aimed to test whether RA signaling pathway can be manipulated to direct the differentiation into sinoatrial node (SAN) CMs. Methods and Results: Using the well-characterized GiWi protocol that cardiomyocytes are generated from hiPSC via temporal modulation of Wnt signaling pathway by small molecules, RA signaling pathway was manipulated during the differentiation of hiPSC-CMs on day 5 post-differentiation, a crucial time point equivalent to the transition from cardiac mesoderm to cardiac progenitor cells in cardiac development. The resultant CMs were characterized at mRNA, protein and electrophysiology levels by a combination of qPCR, immunofluorescence, flow cytometry, and whole-cell patch clamp. The results showed that activation of the RA signaling pathway biased the differentiation of atrial CMs, whereas inhibition of the signaling pathway biased the differentiation of sinoatrial node-like cells (SANLCs). Conclusions: Our study not only provides a novel and simple strategy to enrich SANLCs but also improves our understanding of the importance of RA signaling in the differentiation of hiPSC-CMs.

• Toxicological Research
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• v.7 no.2
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• pp.209-229
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• 1991

In the epidermis of skin, a fine balance exists between proliferating progenitor cells and terminally differentiating cells. We examined the effects of TGF-betas and retinoic acid (RA) on controlling this balance in normal human epidermal keratinocytes cultured under conditions where most morphological and biochemical features of epidermis in vivo are retained. Our results revealed marked and pleiotropic effects of both TGF-beta and RA on kerationcytes. In contrast to retinoids, TGF-betas acted on mitotically active basal cells to retard cell proliferation.

• Animal cells and systems
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• v.2 no.1
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• pp.133-137
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• 1998

The present study aims to characterize a cDNA encoding zebrafish thyroid hormone receptor $\alpha{1}$ $(zTR\alpha{1)}$ in order to investigate its possible role in the early stage of embryonic development. A mobility shift assay showed that $zTR\alpha{1}$ overexpressed in COS7 cells specifically bound to thyroid hormone response element (TRE). In addition, the specific interaction of anti-rat $TR\alpha{1}$ antibodies with $zTR\alpha1$/TRE complexes demonstrated that the cDNA clone encoded zebrafish thyroid hormone receptor $\alpha{1}$. Transient cotransfection assays showed that $zTR\alpha{1}$ repressed the transcription which was induced by retinoic acid (RA), a well-characterized embryonic morphogen. These results suggest that zTRal may be involved in regulating the RA-induced gene transcription during early embryonic development.

• BMB Reports
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• v.46 no.5
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• pp.276-281
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• 2013

In this study, we aimed to compare the morphogenetic and neuronal characteristics between monolayer cells and spheroids. For this purpose, we established spheroid formation by growing SH-SY5Y cells on the hydrophobic surfaces of thermally-collapsed elastin-like polypeptide. After 4 days of culture, the relative proliferation of the cells within spheroids was approximately 92% of the values for monolayer cultures. As measured by quantitative assays for mRNA and protein expressions, the production of synaptophysin and neuronspecific enolase (NSE) as well as the contents of cell adhesion molecules (CAMs) and extracellular matrix (ECM) proteins are much higher in spheroids than in monolayer cells. Under the all-trans-retinoic acid (RA)-induced differentiation condition, spheroids extended neurites and further up-regulated the expression of synaptophysin, NSE, CAMs, and ECM proteins. Our data indicate that RA-differentiated SH-SY5Y neurospheroids are functionally matured neuronal architectures.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.150-156
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• 1999

The induction of proliferation of adult rat islets was investigated under various culture conditions. The islets were isolated from male Sprague-Dawley rats and subsequently embedded in collagen gels, which mimic the in vivo three-dimensional surroundings. During the culture period, the effects of heterologous serum (fetal bovine serum, FBS), epidermal growth factor (EGF), and retinoic acid (RA) on islet growth were examined with respect to the morphological and total DNA content changes. To investigate these changes at the cellular level, whole mount immunocytochemistry using specific antibodies for insulin and glucagon was performed. The results showed that (i) collagen gels as an extracellular matrix can maintain islets in a similar way to that in vivo, (ii) heterologous serum (FBS) had stimulatory effects on islet proliferation in a dose-dependent manner, (iii) RA had inhibitory effects on islet proliferation induced by the serum in a dose-dependent manner, (iv) EGF had weak inhibitory effects on islet proliferation induced by the serum except at the concentration of 10 nM where its effect was not significant, and (v) whole mount immunocytochemistry revealed that newly proliferated islet cells were mainly $\beta$-and $\alpha$-cells.

• Development and Reproduction
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• v.13 no.3
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• pp.155-161
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• 2009

It has been reported that ganglioside GT1b is expressed during neuronal cell differentiation from undifferentiated mouse embryonic stem cells (mESCs), which suggests that ganglioside GT1b has a direct effect on neuronal cell differentiation. Therefore, this study was conducted to evaluate the effect of exogenous addition of ganglioside GT1b to an in vitro model of neuronal cell differentiation from undifferentiated mESCs. The results revealed that a significant increase in the expression of ganglioside GT1b occurred during neuronal differentiation of undifferentiated mESCs. Next, we evaluated the effect of retinoic acid (RA) on GT1b-treated undifferentiated mESCs, which was found to lead to increased neuronal differentiation. Taken together, the results of this study suggest that ganglioside GT1b plays a crucial role in neuronal differentiation of mESCs.