• International Journal of Stem Cells
• /
• v.16 no.3
• /
• pp.260-268
• /
• 2023

Intrauterine adhesion (IUA) can occur after trauma to the basal layer of the endometrium, contributing to severe complications in females, such as infertility and amenorrhea. To date, the proposed therapeutic strategies are targeted to relieve IUA, such as hysteroscopic adhesiolysis, Foley catheter balloon, and hyaluronic acid injection have been applied in the clinic. However, these approaches showed limited effects in alleviating endometrial fibrosis and thin endometrium. Mesenchymal stem cells (MSCs) can offer the potential for endometrium regeneration owing to reduce inflammation and release growth factors. On this basis, MSCs have been proposed as promising methods to treat intrauterine adhesion. However, due to the drawbacks of cell therapy, the possible therapeutic use of extracellular vesicles released by stem cells is raising increasing interest. The paracrine effect, mediated by MSCs derived extracellular vehicles (MSC-EVs), has recently been suggested as a mechanism for their therapeutic properties. Here, we summarizes the main pathological mechanisms involved in intrauterine adhesion, the biogenesis and characteristics of extracellular vesicles, explaining how these vesicles could provide new opportunities for MSCs.

• International Journal of Stem Cells
• /
• v.16 no.3
• /
• pp.251-259
• /
• 2023

Mesenchymal stromal cells (MSCs) have attracted scientific and medical interest due to their self-renewing properties, pluripotency, and paracrine function. However, one of the main limitations to the clinical application of MSCs is their loss of efficacy after transplantation in vivo. Various bioengineering technologies to provide stem cell niche-like conditions have the potential to overcome this limitation. Here, focusing on the stem cell niche microenvironment, studies to maximize the immunomodulatory potential of MSCs by controlling biomechanical stimuli, including shear stress, hydrostatic pressure, stretch, and biophysical cues, such as extracellular matrix mimetic substrates, are discussed. The application of biomechanical forces or biophysical cues to the stem cell microenvironment will be beneficial for enhancing the immunomodulatory function of MSCs during cultivation and overcoming the current limitations of MSC therapy.

• The korean journal of orthodontics
• /
• v.31 no.2 s.85
• /
• pp.237-248
• /
• 2001

Biomechanical reactions of tooth movement are the combination of bone formation and resorption, in which many paracrine factors are involved. The sex hormone is one of the paracrine factors and the sex hormonal level of an adult female vanes according to the body condition, e.g. mensturation, pregnancy, postmenopause, etc. Although the exact mechanism is not clarified yet, estrogen and progesterone are known to regulate the function of osteoblast. Again osteoblast is reported to affect the function of osteoclast. The purpose of this study is to determine the influence of the female sex hormone, estrogen and progesterone, on the cell proliferation and activity of HOS and ROS17/2.8 cell line. The observed results were as follows. 1. Estrogen inhibited HOS cell proliferation and promoted ROS17/2.8 cell proliferation. 2. Estrogen increased the activity of alkaline phosphatase of HOS cell and reduced the activity of alkaline phosphatase of ROS17/2.8 cell. 3. Progesterone inhibited the proliferation of HOS and ROS17/2.8 cell, but had no influence on the activity of alkaline phosphatase. 4. Estrogen and progeterone did not have any particular effects on the activity of super oxide, nitric oxide and gelatinase of HOS and ROS17/2.8 cell.

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

• Journal of Periodontal and Implant Science
• /
• v.44 no.4
• /
• pp.178-183
• /
• 2014

Purpose: The aim of this study was to assess the possible paracrine effect of bone morphogeneticprotein-2 (BMP-2) at the experimental site on the adjacent control site for validating a rabbit calvarial defect model as a means of verifying the effect of BMP-2. Methods: Sixteen rabbits were divided into two groups (n=8 in each) according to whether or not BMP-2 would be used. Two circular defects (8 mm in diameter) were created side by side, 2 mm apart, in the calvarium of all of the rabbits. In each animal, one of the defects was grafted with either BMP-2-loaded carrier or carrier material alone. The control defects adjacent to these grafted defects, designated CB (the nongrafted defect adjacent BMP-2-loaded carrier-grafted defect) and CC (the nongrafted defect adjacent to carrier only-grafted defect), respectively, were the focus of this study, and were filled only with a blood clot in all of the animals. Histologic observation and histomorphometric analysis were performed at 2 and 8 weeks (n=4 animals per point in time) after surgery. Results: There was no noteworthy difference in the healing pattern, and no statistically significant differences in histomorphometric parameters such as the defect closure, new bone area, or total augmented area between the CC and CB groups. Conclusions: The results of this study suggest that rabbit calvarial defects separated by a distance of 2 mm are suitable for evaluating the effects of BMP-2 and the control defect can be regarded not to be affected by BMP-2 applied defect.

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

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.1
• /
• pp.64-70
• /
• 2010

Soybean is of particular interest as a food supplement of isoflavones for inhibiting bone resorption in postmenopausal woman. These beneficial effects of isoflavones are caused by functioning as partial agonists or antagonists of estrogen, of which anti-resorptive effect is mediated indirectly through paracrine factors produced by osteoblasts that act on osteoclasts. In this study, the indirect effect of soybean on osteoclastic differentiation of RAW264.7 cells were investigated. The conditioned medium was collected from MC3T3-E1 osbeoblasts treated with 0.001 mg/mL~0.1 mg/mL soybean extracts for 6 days, mixed in 1:1 ratio with osteoclast medium, and then added into RAW264.7 cells with receptor activator of nuclear factor kappa B ligand (RANKL), a differentiation inducer for 3 days. Of paracrine factors in the conditioned medium, the protein expression of osteoprotegerin (OPG) with soybean extract was specifically higher in a dose dependent manner than with $10^{-9}$ M~$10^{-6}$ M of estrogen, genistein or daidzein standards. In RAW264.7 cells, the conditioned medium with soybean inhibited RANKL induced osteoclastic differentiation as total number of multinucleated tartrateresistant alkaline phosphatase (TRAP)-positive osteoclasts and protein expression of MMP-9 were significantly decreased. Coupled with the low expression of estrogen receptor $\alpha$ and $\beta$ proteins in RANKL treated RAW264.7 cells, we demonstrate that the conditioned medium of soybean treated osteoblasts inhibits RANKL induced differentiation of osteoclasts with the selective expression of OPG in osteoblasts.

• Development and Reproduction
• /
• v.2 no.1
• /
• pp.21-27
• /
• 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
• /
• v.28 no.6 s.71
• /
• pp.915-926
• /
• 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-$\alpha$.

• Korean Journal of Animal Reproduction
• /
• v.21 no.1
• /
• pp.61-69
• /
• 1997

The present study was carried out to investigate the effects of EGF and anti-EGF on early embryonic development and hatching in mice. Developmental and hatching rates of mouse em-bryos from 2-cell to morular stage which were cultured in Ham's FlO medium supplemented with EGF (1-1,000 ng/ml) or anti-EGF (whole serum diluted from 1:10 to 1:1,000) were compared to those of control When mouse early 2-cell embryos were cultured in the EGF supplemented medium, blastulation was accelerated compared with control. Hatching rate was also significantly (p