• Molecules and Cells
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• v.38 no.12
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• pp.1023-1028
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• 2015

Whole body energy balance is achieved through the coordinated regulation of energy intake and energy expenditure in various tissues including liver, muscle and adipose tissues. A positive energy imbalance by excessive energy intake or insufficient energy expenditure results in obesity and related metabolic diseases. Although there have been many obesity treatment trials aimed at the reduction of energy intake, these strategies have achieved only limited success because of their associated adverse effects. An ancient neurotransmitter, serotonin is among those traditional pharmacological targets for anti-obesity treatment because it exhibits strong anorectic effect in the brain. However, recent studies suggest the new functions of peripheral serotonin in energy homeostasis ranging from the endocrine regulation by gut-derived serotonin to the autocrine/paracrine regulation by adipocyte-derived serotonin. Here, we discuss the role of serotonin in the regulation of energy homeostasis and introduce peripheral serotonin as a possible target for anti-obesity treatment.

• BMB Reports
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• v.56 no.7
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• pp.365-373
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• 2023

Loss of skeletal muscle mass is a primary feature of sarcopenia and cancer cachexia. In cancer patients, tumor-derived inflammatory factors promote muscle atrophy via tumor-to-muscle effects, which is closely associated with poor prognosis. During the past decade, skeletal muscle has been considered to function as an autocrine, paracrine, and endocrine organ by releasing numerous myokines. The circulating myokines can modulate pathophysiology in the other organs, as well as in the tumor microenvironment, suggesting myokines function as muscle-to-tumor signaling molecules. Here, we highlight the roles of myokines in tumorigenesis, particularly in terms of crosstalk between skeletal muscle and tumor. Better understanding of tumor-to-muscle and muscle-to-tumor effects will shed light on novel strategies for the diagnosis and treatment of cancer.

• Progress in Medical Physics
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• v.25 no.3
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• pp.157-166
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• 2014

ATP in quantity co-stored with neurotransmitters in the secretory vesicles of neurons, by being co-released with the neurotransmitters, takes an important role to modulate the stimulus-secretion response of neurotransmitters. Here, in this study, the modulatory effect of ATP was studied in $Ca^{2+}$ channels of cultured rat adrenal chromaffin cells to investigate the physiological role of ATP in neurons. The $Ca^{2+}$ channel current was recorded in a whole-cell patch clamp configuration, which was modulated by ATP. In 10 mM $Ba^{2+}$ bath solution, ATP treatment (0.1 mM) decreased the $Ba^{2+}$ current by an average of $36{\pm}6%$ (n=8), showing a dose-dependency within the range of $10^{-4}{\sim}10^{-1}mM$. The current was recovered by ATP washout, demonstrating its reversible pattern. This current blockade effect of ATP was disinhibited by a large prepulse up to +80 mV, since the $Ba^{2+}$ current increment was larger when treated with ATP ($37{\pm}5%$, n=11) compared to the control ($25{\pm}3%$, n=12, without ATP). The $Ba^{2+}$ current was recorded with $GTP{\gamma}S$, the non-hydrolyzable GTP analogue, to determine if the blocking effect of ATP was mediated by G-protein. The $Ba^{2+}$ current decreased down to 45% of control with $GTP{\gamma}S$. With a large prepulse (+80 mV), the current increment was $34{\pm}4%$ (n=19), which $25{\pm}3%$ (n=12) under control condition (without $GTP{\gamma}S$). The $Ba^{2+}$ current waveform was well fitted to a single-exponential curve for the control, while a double-exponential curve best fitted the current signal with ATP or $GTP{\gamma}S$. In other words, a slow activation component appeared with ATP or $GTP{\gamma}S$, which suggested that both ATP and $GTP{\gamma}S$ caused slower activation of $Ca^{2+}$ channels via the same mechanism. The results suggest that ATP may block the $Ca^{2+}$ channels by G-protein and this $Ca^{2+}$ channel blocking effect of ATP is important in autocrine (or paracrine) inhibition of adrenaline secretion in chromaffin cell.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.217-224
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• 2008

Angiogenesis plays an important role in bone development and postnatal bone fracture repair. Vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) have been thought to be primarily involved in promoting angiogenesis. It is well known that VEGF and its receptors have been reported to play an important role in the regulation of the interaction between angiogenesis and osteogenesis during bone repair processes. Dexamethasone, a potent synthetic glucocorticoid, promotes phenotype markers of osteoblast differentiation, such as ALP and osteocalcin. It stimulates in vitro osteogenesis of human bone marrow osteogenic stromal cells. Dexamethasone has been reported to suppress VEGF gene expression in some cells. However, our previous study demonstrated VEGF quantification increased in a time-dependent manner in periosteal-derived osteogenesis under dexamethasone. So, the purpose of this study was to examine the angiogenic phenotypes in cultured human periosteal-derived cells under high-dose dexamethasone. Periosteal-derived cells were cultured using a technique previously described. After passage 3, the periosteal-derived cells were further cultured for 28 days in an osteogenic inductive culture medium containing ascorbic acid, ${\beta}$-glycerophosphate and high-dose dexamethasone, We evaluated the expression of VEGF isoforms, VEGFR-1, VEGFR-2, and neuropilin-1, ALL VEGF isoforms ($VEGF_{121},\;VEGF_{165},\;VEGF_{189}$, and $VEGF_{206}$) expression was observed by RT-PCR analysis. VEGFR-1, VEGFR-2 and neuropilin-1 expression increased up to day 14, particularly during the early stage of mineralization. Our results suggest the involvement of direct VEGFs/VEGFRs system on periosteal-derived cells during early mineralization phase under high-dose of dexamethasone. These also suggest that VEGF might act as an autocrine growth molecule during osteoblastic differentiation of cultured human periosteal-derived cells.

• Development and Reproduction
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• v.2 no.2
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• pp.189-196
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• 1998

Several lines of evidence indicate that some neuropeptides classically associated hypothalamus have been found in pituitary gland, suggesting the existence of local regulation of pituitary function. Among the hypothalamic releasing hormones, genes for TRH and GnRH are expressed in the rat anterior pituitary gland. The present study was carried out to investigate the expression of the GHRH gene in rat anterior pituitary and the pituitary-derived cell lines. The presence of GHRH transcripts in pituitary tissue was shown by 3'rapid amplification of cDNA end (3'-RACE) analysis. In reverse transcription-polymerase chain reaction (RT-PCR) study, GHRH cDNA fragments were amplified from two pituitary-derived cell lines, $\alpha$T3 cells originated from mouse gonadotrope and GH3 cells from rat somatolactotrope. Immunoreactive GHRH was detected in large and medium-sized pituitary cells by immunocytochemistry. Significant amounts of GHRH-like molecules were found in the GH3 cell extracts. In RNase protection assay, the level of pituitary GHRH mRNA was augmented by ovariectomy. These results demonstrate that GHRH gene is expressed in the rat gonadotropes and somatotropes, and suggest that the pituitary GHRH could be participated in the paracrine and/or autocrine regulation of cell proliferation, as well as promoting growth hormone secretion.

• Development and Reproduction
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• v.4 no.2
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• pp.237-242
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• 2000

Growth hormone releasing hormone (GHRH), the major hypothalamic stimulus of GH secretion from the anterior pituitary gland, has been found to be present in several extrahypothalamic sites including placenta testis, ovary and anterior pituitary gland. The present study was performed to elucidate the role of pituitary GHRH on proliferation of cells derived from rat anterior pituitary gland. The GHRH content of pituitary tissue, cultured pituitary cells, and the conditioned media was evaluated by radioimmunoassay (RIA). Primary cultures of pituitary cells derived from adult rats were prepared by enzymatic dispersion. Significant amounts of GHRH-like molecules were detected in both pituitary tissue and cell cultures by GHRH RIA. Competition curves with increasing amounts of tissue extracts and conditioned media were parallel with those of standard peptide, indicating that the pituitary GHRH-like material is similar to authentic GHRH. To analyze specific cell types responsible for producing GHRH in anteroior pituitary, cell fractionation technique combined with GHRH RIA was performed. In cell fractionation experiment, the highest level of GHRH content was found in gonadotrope enriched-fraction and followed by somatotrope-, lactotrope- and thyrotrope-fraction. Treatment of pituitary cells with GHRH resulted in a dose-dependent increase in [$^3$H] thymidine incorporation. The mitogenic effect of GHRH could be mediated by typical oncogenic activation since the GHRH induced transient increase in c-fos mRNA levels with peak response at 30 minutes. The present study demonstrated that i) the pituitary GHRH expressed in the rat anterior pituitary gland can be secreted, ii) among the various cell types, gonadotropes and somatotorpes are the major GHRH source, and iii) the GHRH treatment increased the [$^3$H] thymidine incorporation and c-fos transcriptional activity in the pituitary cell culture. These findings suggested that GHRH could participated in the paracrine and/or autocrine regulation of cell proliferation, as well as promoting growth hormone secretion.

• Development and Reproduction
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• v.2 no.1
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• pp.21-27
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• 1998

The present study was performed to analyze the gene expressions of pituitary adenylate cyclase-activating polypeptide(PACAP) and its receptor in the rat uterus, a candidate for novel extrahypothalamic source and target. The PACAP cDNA fragments corresponding to the common exon region which is found in both the rat hypothalamus and testis were produced from all tissue samples including the rat uterus by reverse transcriptionpolymerase chain reaction (RT-PCR). No PCR product was amplified from the rat hypothalamic, pituitary, ovarian and uterine samples when the 5' primer corresponding to the testis-specific exon 1 region was used, while the predicted size of product was detected from the testis sample. RT-PCR using the uterine RNA and specific primers for the PACAP receptor yielded products with predicted sizes. Transcripts for the rat uterine PACAP receptor were identified as type I isoforms with hip-hop and hip- or hop-type inserts. After pregnant mare's serum gonadotropin (15 IU) treatment of immature rats (day 25), the level of PACAP mRNA was increased in 24 h and 48 h group, and was declined to the lowest in 72 h group. The present study shows the presence of transcripts for PACAP and its receptor isoform in the rat uterus. These finding ssuggest that the uterine PACAP ight act as a novel autocrine and/or paracrine factor via its specific receptors on the reglulation of rat uterine function and physiology during the reproductive cycle.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.915-926
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• 1998

The cytoskeleton has been shown to form a network, connecting the extracelluar matrix via integrin with the nucleus and the cytoplasmic constituents of the cell. It is therefore assumed that the cytoskeleton may mediate signals generated by perturbations originating in the matrix. The purpose of this study is to examine the effect of cytoskeletal change on osteoblastic cell activities. The author cultured osteoblastic cells obtained from neonatal mouse calvaria. The cells were teated with cytochalasin B(CB) or colchicine (COL) at four concentrations for 3 hours and after another 24 hours the conditioned media was collected and assayed for prostaglandin $E_2\;(PGE_2)$, interleukin-6(IL-6), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and matrix metalloproteinase-1(MMP-1). In addition, the cytoskeletal protein actin were observed by immuno-fluorescence. The results were as follows: 1. The production of $PGE_2$ showed the tendency to be increased in CB-treated group. $PGE_2$ was increased in COL-treated group dose-dependantly, 2. IL-6 production, in CB-treated group, was increased, except at 1.0 ${\mu}g/ml$. IL-6 was induced in COL-treated group. 3. TNF-$\alpha$ production was increased in CB-treated group, except at 1.0 ${\mu}g/ml$, and in COL-treated group, that was increased. 4. The MMP-1 production was decreased in CB-treated soup and was not changed in COL-treated group, which could be selectively visualized by immunoblotting with monospecific antibody. 5. The cytoskeletal actin stress fibers were disappeared and the cells showed to be rounded in CB-treated group. These results indicated that there are a relationship between the cytoskeletal rearrangements and osteoblastic cell activities, especially in release of paracrine/autocrine factors, such as $PGE_2$, IL-6, and TNF-$\alpha$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.437-443
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• 2003

Epidemiological data suggest that lycopene has anticancer activities in humans. Insulin-like growth factor-I receptor (IGF-IR) is a transmembrane tyrosine kinase that mediates the biological actions of IGFs and may play an active role in cancer progression. Because our previous in vitro studies have indicated lycopene inhibits HT-29 cell growth, the aim of this study was to determine whether lycopene induces apoptotic cell death and the inhibitory effect of lycopene on HT-29 cell growth is related to changes in IGF-IR levels and the receptor's intracellular signalling pathways. HT-29 cells were incubated for 4 days in serum-free medium in the presence of 0, 25, 50, or 100 $\mu$M lycopene, and the DNA fragmentation assay was performed. Cells treated with lycopene produced a distinct oligonucleosomal ladder with different sizes of DNA fragments, a typical characteristic of cells undergoing apoptosis. HT-29 cells were cultured for 4 days in serum-free medium in the presence of 0~100 $\mu$M lycopene and IGF-I (10nM) was added for 0~60 minutes immediately prior to lysate preparations. Western blot analysis of total lysates revealed that lycopene decreased the levels of IRS-1, Akt, phosphatidylinositol 3-kinase (PI3K), and IGF-IR $\beta$-subunit, and increased the levels of the IGF-IR precursor dose dependently. Lycopene also decreased IGF-I-induced phosphorylation of IGF-IR$\beta$, IRS-1 and Akt, which were, at least in part, due to decreased expression of these proteins. These results suggest that lycopene induces apoptosis of HT-29 cells by inhibiting IGF-IR signaling thereby interfering with an IGF-II-driven autocrine growth loop, which is known to exist in this cell line.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.2
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• pp.106-109
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• 2000

Vascular endothelial cells (EGs) are usually difficult to culture to culture in a large scale because of their complicated requirements for cell growth. As the vascular endothelial growth factor (VEGF) is a key growth factor in the EC culture, we transfected human umbilical vein endothelial cells (HUVEC) using a plasmid containing VEGF gene and let them grow in a culture medium eliminated an important supplement, endothelail cell growth supplement(ECGS). The expression of VEGF by HUVEC tansfected with Vegf GENE was not enough to stimulate the growth of HUVEC, only 40% of maximum cell density obtainable in the presence of ECGS. However, when the culture medium was supplied with 2.5 ng/ml of basic fibroblast growth factor (bFGF), a synergistic effect effect of VEGE and bFGF was observed. In this case, the final cell density was recovered was recovered up to about 78% of maxium value.