ABSTRACT
BACKGROUND@#Chondroitin sulfate glycosaminoglycans (CS-GAGs) are the primary inhibitory GAGs for neuronal growth after central nervous system (CNS) injury. However, the inhibitory or permissive activity of CS-GAG subtypes is controversial and depends on the physiological needs of CNS tissues. In this study, we investigated the characteristics and effects of CS-GAGs on axonal growth, which was isolated from the brain cortices of normal rat embryo at E18, normal adult rat brain and injured adult rat brain. @*METHODS@#Isolated CS-GAGs from embryo, normal adult, and injured adult rat brains were used for analyzing their effect on attachment and axonal growth using modified spot assay with dorsal root ganglion (DRG) explants and cerebellar granule neurons (CGNs). CS-GAGs were separated using high performance liquid chromatography (HPLC), and the subtypes of CS-GAGs were analyzed. @*RESULTS@#CS-GAGs of all three groups inhibited CGN attachment and axonal growth of DRGs. However, CS-GAGs of normal adult rat brain exhibited higher inhibitory activity than those of the other groups in both assays. When subtypes of CS-GAGs were analyzed using HPLC, CS-A (4S) was the most abundant in all three groups and found in largest amount in normal adult rat brain. In contrast, unsulfated CS (CS0) and CS-C (6S) were more abundant by 3–4-folds in E18 group than in the two adult groups. @*CONCLUSION@#When compared with the normal adult rat brain, injured rat brain showed relatively similar patterns to that of embryonic rat brain at E18 in the expression of CS subtypes and their inhibitory effect on axonal growth. This phenomenon could be due to differential expression of CS-GAGs subtypes causing decrease in the amount of CS-A and mature-type CS proteoglycan core proteins.
ABSTRACT
BACKGROUND@#Corneal scarring or disease may lead to severe corneal opacification and consequently, severe loss of vision due to the complete loss of corneal epithelial cells. We studied the use of epithelial cell sheets differentiated from fetal cartilage-derived stem cells (FCSC) to resurface damaged cornea. @*METHODS@#The FCSC were isolated from the femoral head of immature cartilage tissue. The ability of the FCSCs to differentiate into corneal epithelial cells was evaluated using differentiation media at 2 days and 7 days post-seeding. A sheet fabricated of FCSCs was also used for the differentiation assay. The results of the in vitro studies were evaluated by immunocytochemistry and Western blots for corneal epithelial cell markers (CK3/12 and Pax6) and limbal epithelial stem cell markers (ABCG2 and p63). To test the material in vivo, an FCSC-sheet was applied as a treatment in a chemically burned rabbit model. The healing ability was observed histologically one week after treatment. @*RESULTS@#The in vitro experiments showed morphological changes in the FCSCs at two and seven days of culture. The differentiated cells from the FCSCs or the FCSC-sheet expressed corneal epithelial cells markers. FCSC were create cell sheet that successfully differentiated into corneal epithelial cells and had sufficient adhesion so that it could be fused to host tissue after suture to the ocular surface with silk suture. The implanted cell sheet maintained its transparency and the cells were alive a week after implantation. @*CONCLUSION@#These results suggest that carrier-free sheets fabricated of FCSCs have the potential to repair damaged corneal surfaces.
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BACKGROUND@#Exosomes from mesenchymal stem cells (MSCs) show anti-inflammatory effect on osteoarthritis (OA); however, their biological effect and mechanism are not yet clearly understood. This study investigated the anti-inflammatory effect and mechanism of MSC-derived exosomes (MSC-Exo) primed with IL-1β in osteoarthritic SW982 cells. @*METHODS@#SW982 cells were treated with interleukin (IL)-1β and tumor necrosis factor (TNF)-α to induce the OA phenotype. The effect of exosomes without priming (MSC-Exo) or with IL-1β priming (MSC-IL-Exo) was examined on the expression of pro- or anti-inflammatory factors, and the amount of IκBα was examined in SW982 cells. Exosomes were treated with RNase to remove RNA. The role of miR-147b was examined using a mimic and an inhibitor. @*RESULTS@#MSC-IL-Exo showed stronger inhibitory effects on the expression of pro-inflammatory cytokines (IL-1β, IL-6, and monocyte chemoattractant protein-1) than MSC-Exo. The expression of anti-inflammatory factors (SOCS3 and SOCS6) was enhanced by MSCs-IL-Exo. Priming with IL-1β increased RNA content in MSC-IL-Exo, and pretreatment with RNase abolished anti-inflammatory effect in SW982 cells. miR-147b was found in much larger amounts in MSC-IL-Exo than in MSC-Exo. The miR-147b mimic significantly inhibited the expression of inflammatory cytokines, while the miR-147b inhibitor only partially blocked the anti-inflammatory effect of MSC-IL-Exo. MSC-IL-Exo and miR-147b mimic inhibited the reduction of IκBα, an nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor, by IL-1β and TNF-α. @*CONCLUSION@#This study showed that MSC exosomes with IL-1β priming exhibit significantly enhanced anti-inflammatory activity in osteoarthritic SW982 cells. The effect of IL-1β-primed MSC exosomes is mediated by miRNAs such as miR-147b and involves inhibition of the NF-κB pathway.
ABSTRACT
BACKGROUND@#Chondroitin sulfate glycosaminoglycans (CS-GAGs) are the primary inhibitory GAGs for neuronal growth after central nervous system (CNS) injury. However, the inhibitory or permissive activity of CS-GAG subtypes is controversial and depends on the physiological needs of CNS tissues. In this study, we investigated the characteristics and effects of CS-GAGs on axonal growth, which was isolated from the brain cortices of normal rat embryo at E18, normal adult rat brain and injured adult rat brain. @*METHODS@#Isolated CS-GAGs from embryo, normal adult, and injured adult rat brains were used for analyzing their effect on attachment and axonal growth using modified spot assay with dorsal root ganglion (DRG) explants and cerebellar granule neurons (CGNs). CS-GAGs were separated using high performance liquid chromatography (HPLC), and the subtypes of CS-GAGs were analyzed. @*RESULTS@#CS-GAGs of all three groups inhibited CGN attachment and axonal growth of DRGs. However, CS-GAGs of normal adult rat brain exhibited higher inhibitory activity than those of the other groups in both assays. When subtypes of CS-GAGs were analyzed using HPLC, CS-A (4S) was the most abundant in all three groups and found in largest amount in normal adult rat brain. In contrast, unsulfated CS (CS0) and CS-C (6S) were more abundant by 3–4-folds in E18 group than in the two adult groups. @*CONCLUSION@#When compared with the normal adult rat brain, injured rat brain showed relatively similar patterns to that of embryonic rat brain at E18 in the expression of CS subtypes and their inhibitory effect on axonal growth. This phenomenon could be due to differential expression of CS-GAGs subtypes causing decrease in the amount of CS-A and mature-type CS proteoglycan core proteins.
ABSTRACT
BACKGROUND@#Corneal scarring or disease may lead to severe corneal opacification and consequently, severe loss of vision due to the complete loss of corneal epithelial cells. We studied the use of epithelial cell sheets differentiated from fetal cartilage-derived stem cells (FCSC) to resurface damaged cornea. @*METHODS@#The FCSC were isolated from the femoral head of immature cartilage tissue. The ability of the FCSCs to differentiate into corneal epithelial cells was evaluated using differentiation media at 2 days and 7 days post-seeding. A sheet fabricated of FCSCs was also used for the differentiation assay. The results of the in vitro studies were evaluated by immunocytochemistry and Western blots for corneal epithelial cell markers (CK3/12 and Pax6) and limbal epithelial stem cell markers (ABCG2 and p63). To test the material in vivo, an FCSC-sheet was applied as a treatment in a chemically burned rabbit model. The healing ability was observed histologically one week after treatment. @*RESULTS@#The in vitro experiments showed morphological changes in the FCSCs at two and seven days of culture. The differentiated cells from the FCSCs or the FCSC-sheet expressed corneal epithelial cells markers. FCSC were create cell sheet that successfully differentiated into corneal epithelial cells and had sufficient adhesion so that it could be fused to host tissue after suture to the ocular surface with silk suture. The implanted cell sheet maintained its transparency and the cells were alive a week after implantation. @*CONCLUSION@#These results suggest that carrier-free sheets fabricated of FCSCs have the potential to repair damaged corneal surfaces.
ABSTRACT
BACKGROUND@#Exosomes from mesenchymal stem cells (MSCs) show anti-inflammatory effect on osteoarthritis (OA); however, their biological effect and mechanism are not yet clearly understood. This study investigated the anti-inflammatory effect and mechanism of MSC-derived exosomes (MSC-Exo) primed with IL-1β in osteoarthritic SW982 cells. @*METHODS@#SW982 cells were treated with interleukin (IL)-1β and tumor necrosis factor (TNF)-α to induce the OA phenotype. The effect of exosomes without priming (MSC-Exo) or with IL-1β priming (MSC-IL-Exo) was examined on the expression of pro- or anti-inflammatory factors, and the amount of IκBα was examined in SW982 cells. Exosomes were treated with RNase to remove RNA. The role of miR-147b was examined using a mimic and an inhibitor. @*RESULTS@#MSC-IL-Exo showed stronger inhibitory effects on the expression of pro-inflammatory cytokines (IL-1β, IL-6, and monocyte chemoattractant protein-1) than MSC-Exo. The expression of anti-inflammatory factors (SOCS3 and SOCS6) was enhanced by MSCs-IL-Exo. Priming with IL-1β increased RNA content in MSC-IL-Exo, and pretreatment with RNase abolished anti-inflammatory effect in SW982 cells. miR-147b was found in much larger amounts in MSC-IL-Exo than in MSC-Exo. The miR-147b mimic significantly inhibited the expression of inflammatory cytokines, while the miR-147b inhibitor only partially blocked the anti-inflammatory effect of MSC-IL-Exo. MSC-IL-Exo and miR-147b mimic inhibited the reduction of IκBα, an nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor, by IL-1β and TNF-α. @*CONCLUSION@#This study showed that MSC exosomes with IL-1β priming exhibit significantly enhanced anti-inflammatory activity in osteoarthritic SW982 cells. The effect of IL-1β-primed MSC exosomes is mediated by miRNAs such as miR-147b and involves inhibition of the NF-κB pathway.
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BACKGROUND@#To regenerate tissue-engineered cartilage as a source of material for the restoration of cartilage defects, we used a human fetal cartilage progenitor cell pellet to improve chondrogenesis and modulation of the immune response in an In Vivo bioreactor (IVB) system. @*METHODS@#IVB was buried subcutaneously in the host and then implanted into a cartilage defect. The IVB was composed of a silicone tube and a cellulose nano pore-sized membrane. First, fetal cartilage progenitor cell pellets were cultured in vitro for 3 days, then cultured in vitro, subcutaneously, and in an IVB for 3 weeks. First, the components and liquidity of IVB fluid were evaluated, then the chondrogenesis and immunogenicity of the pellets were evaluated using gross observation, cell viability assays, histology, biochemical analysis, RT-PCR, and Western blots. Finally, cartilage repair and synovial inflammation were evaluated histologically. @*RESULTS@#The fluid color and transparency of the IVB were similar to synovial fluid (SF) and the components were closer to SF than serum. The IVB system not only promoted the synthesis of cartilage matrix and maintained the cartilage phenotype, it also delayed calcification compared to the subcutaneously implanted pellets. @*CONCLUSION@#The IVB adopted to study cell differentiation was effective in preventing host immune rejection.
ABSTRACT
BACKGROUND@#The extracellular matrix (ECM) of articular cartilage has an inhibitory effect on vascularization, yet clinical utilization has been technically challenging. In this study, we aimed to fabricate a biologically functional ECM powder suspension from porcine articular cartilage that inhibits neovascularization (NV). @*METHODS@#The digested-cartilage acellular matrix (dg-CAM) was prepared by sequential processes of decellularization, enzymatic digestion and pulverization. Physicochemical properties of dg-CAM were compared with that of native cartilage tissue (NCT). Cellular interactions between human umbilical vein endothelial cells (HUVECs) and dg-CAM was evaluated with proliferation, migration and tube formation assays compared with that of type I collagen (COL) and bevacizumab, an anti-angiogenic drug. We then investigated the therapeutic potential of topical administration of dg-CAM suspension on the experimentally induced rabbit corneal NV model. @*RESULTS@#The dg-CAM released a significantly larger amount of soluble proteins than that of the NCT and showed an improved hydrophilic and dispersion properties. In contrast, the dg-CAM contained a large amount of collagen, glycosaminoglycans and anti-angiogenic molecules as much as the NCT. The inhibitory effect on NV of the dg-CAM was more prominent than that of COL and even comparable to that of bevacizumab in inhibiting the HUVECs. The therapeutic potential of the dg-CAM was comparable to that of bevacizumab in the rabbit corneal NV model by efficiently inhibiting neovessel formation of the injured cornea. @*CONCLUSION@#The current study developed a dg-CAM having anti-angiogenic properties, together with water-dispersible properties suitable for topical or minimally invasive application for prevention of vessel invasion.
ABSTRACT
BACKGROUND@#The extracellular matrix (ECM) of articular cartilage has an inhibitory effect on vascularization, yet clinical utilization has been technically challenging. In this study, we aimed to fabricate a biologically functional ECM powder suspension from porcine articular cartilage that inhibits neovascularization (NV). @*METHODS@#The digested-cartilage acellular matrix (dg-CAM) was prepared by sequential processes of decellularization, enzymatic digestion and pulverization. Physicochemical properties of dg-CAM were compared with that of native cartilage tissue (NCT). Cellular interactions between human umbilical vein endothelial cells (HUVECs) and dg-CAM was evaluated with proliferation, migration and tube formation assays compared with that of type I collagen (COL) and bevacizumab, an anti-angiogenic drug. We then investigated the therapeutic potential of topical administration of dg-CAM suspension on the experimentally induced rabbit corneal NV model. @*RESULTS@#The dg-CAM released a significantly larger amount of soluble proteins than that of the NCT and showed an improved hydrophilic and dispersion properties. In contrast, the dg-CAM contained a large amount of collagen, glycosaminoglycans and anti-angiogenic molecules as much as the NCT. The inhibitory effect on NV of the dg-CAM was more prominent than that of COL and even comparable to that of bevacizumab in inhibiting the HUVECs. The therapeutic potential of the dg-CAM was comparable to that of bevacizumab in the rabbit corneal NV model by efficiently inhibiting neovessel formation of the injured cornea. @*CONCLUSION@#The current study developed a dg-CAM having anti-angiogenic properties, together with water-dispersible properties suitable for topical or minimally invasive application for prevention of vessel invasion.
ABSTRACT
BACKGROUND: This study was conducted to investigate the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the mobilization of mesenchymal stem cells (MSCs) from the bone marrow (BM) into the peripheral blood (PB) in rats. METHODS: GM-CSF was administered subcutaneously to rats at 50 µg/kg body weight for 5 consecutive days. The BM and PB of rats were collected at 1, 3, and 5 days during the administration for analysis. RESULTS: Upon GM-CSF administration, the number of mononuclear cells increased rapidly at day 1 both in the BM and PB. This number decreased gradually over time in the BM to below the initial amount by day 5, but was maintained at a high level in the PB until day 5. The colony-forming unit-fibroblasts were increased in the PB by 10.3-fold at day 5 of GM-CSF administration, but decreased in the BM. Compared to GM-CSF, granulocyte-colony stimulating factor (G-CSF) stimulated lower levels of MSC mobilization from the BM to the PB. Immunohistochemical analysis revealed that GM-CSF induced a hypoxic and proteolytic microenvironment and increased C-X-C chemokine receptor type 4 (CXCR4) expression in the BM. GM-CSF added to BM MSCs in vitro dose-dependently increased CXCR4 expression and cell migration. G-CSF and stromal cell derived factor-1 (SDF-1) showed similar results in these in vitro assays. Know-down of CXCR4 expression with siRNA significantly abolished GM-CSF- and G-CSF-induced MSC migration in vitro, indicating the involvement of the SDF-1-CXCR4 interaction in the mechanism. CONCLUSION: These results suggest that GM-CSF is a useful tool for mobilizing BM MSCs into the PB.
Subject(s)
Animals , Rats , Hypoxia , Body Weight , Bone Marrow , Cell Movement , Granulocyte Colony-Stimulating Factor , Granulocyte-Macrophage Colony-Stimulating Factor , In Vitro Techniques , Mesenchymal Stem Cells , RNA, Small Interfering , Stromal CellsABSTRACT
BACKGROUND: Stem cell therapy requires a serum-free and/or chemically-defined medium for commercialization, but it is difficult to find one that supports long-term expansion of cells without compromising their stemness, particularly for novel stem cells. METHODS: In this study, we tested the efficiency of StemPro® MSC SFM Xeno Free (SFM-XF), a serum-free medium, for the long-term expansion of human fetal cartilage-derived progenitor cells (hFCPCs) from three donors in comparison to that of the conventional α-Modified Eagle's Medium (α-MEM) supplemented with 10% fetal bovine serum (FBS). RESULTS: We found that SFM-XF supported the expansion of hFCPCs for up to 28–30 passages without significant changes in the doubling time, while α-MEM with 10% FBS showed a rapid increase in doubling time at 10–18 passages depending on the donor. Senescence of hFCPCs was not observed until passage 10 in both media but was induced in approximately 15 and 25% of cells at passage 20 in SFM-XF and α-MEM with 10% FBS, respectively. The colony forming ability of hFCPCs in SFX-XF was also comparable to that in α-MEM with 10% FBS. hFCPCs expressed pluripotency genes like Oct-4, Sox-2, Nanog, SCF, and SSEA4 at passage 20 and 31 in SFM-XF; however, this was not observed when cells were cultured in α-MEM with 10% FBS. The ability of hFCPCs to differentiate into three mesodermal lineages decreased gradually in both media but it was less significant in SFM-XF. Finally we found no chromosomal abnormality after long-term culture of hFCPCs until passage 17 by karyotype analysis. CONCLUSION: These results suggest that SFM-XF supports the long-term expansion of hFCPCs without significant phenotypic and chromosomal changes. This study have also shown that hFCPCs can be mass-produced in vitro, proving their commercial value as a novel source for developing cell therapies.
Subject(s)
Humans , Aging , Cartilage , Cell- and Tissue-Based Therapy , Chromosome Aberrations , In Vitro Techniques , Karyotype , Mesoderm , Stem Cells , Tissue DonorsABSTRACT
BACKGROUND: Mass production of exosomes is a prerequisite for their commercial utilization. This study investigated whether three-dimensional (3D) spheroid culture of mesenchymal stem cells (MSCs) could improve the production efficiency of exosomes and if so, what was the mechanism involved. METHODS: We adopted two models of 3D spheroid culture using the hanging-drop (3D-HD) and poly(2-hydroxyethyl methacrylate) (poly-HEMA) coating methods (3D-PH). The efficiency of exosome production from MSCs in the 3D spheroids was compared with that of monolayer culture in various conditions. We then investigated the mechanism of the 3D spheroid culture-induced increase in exosome production. RESULTS: The 3D-HD formed a single larger spheroid, while the 3D-PH formed multiple smaller ones. However, MSCs cultured on both types of spheroids produced significantly more exosomes than those cultured in conventional monolayer culture (2D). We then investigated the cause of the increased exosome production in terms of hypoxia within the 3D spheroids, high cell density, and non-adherent cell morphology. With increasing spheroid size, the efficiency of exosome production was the largest with the least amount of cells in both 3D-HD and 3D-PH. An increase in cell density in 2D culture (2D-H) was less efficient in exosome production than the conventional, lower cell density, 2D culture. Finally, when cells were plated at normal density on the poly-HEMA coated spheroids (3D-N-PH); they formed small aggregates of less than 10 cells and still produced more exosomes than those in the 2D culture when plated at the same density. We also found that the expression of F-actin was markedly reduced in the 3D-N-PH culture. CONCLUSION: These results suggested that 3D spheroid culture produces more exosomes than 2D culture and the non-adherent round cell morphology itself might be a causative factor. The result of the present study could provide useful information to develop an optimal process for the mass production of exosomes.
Subject(s)
Actins , Hypoxia , Cell Count , Exosomes , Mesenchymal Stem Cells , Polyhydroxyethyl MethacrylateABSTRACT
It is very useful to evaluate the content and 3D distribution of extracellular matrix non-destructively in tissue engineering. This study evaluated the feasibility of using micro-computed tomography (µCT) with Hexabrix to measure quantitatively sulfated glycosaminoglycans (GAGs) of engineered cartilage. Rabbit chondrocytes at passage 2 were used to produce artificial cartilages in polyglycolic acid scaffolds in vitro. Engineered cartilages were incubated with Hexabrix 320 for 20 min and analyzed via µCT scanning. The number of voxels in the 2D and 3D scanning images were counted to estimate the amount of sulfated GAGs. The optimal threshold value for quantification was determined by regression analysis. The 2D µCT images of an engineered cartilage showed positive correlation with the histological image of Safranin-O staining. Quantitative data obtained with the 3D µCT images of 14 engineered cartilages showed strong correlation with sulfated GAGs contents obtained by biochemical analysis (R² = 0.883, p < 0.001). Repeated exposure of engineered cartilages to Hexabrix 320 and µCT scanning did not significantly affect cell viability, total DNA content, or the total content of sulfated GAGs. We conclude that µCT imaging using Hexabrix 320 provides high spatial resolution and sensitivity to assess the content and 3D distribution of sulfated GAGs in engineered cartilages. It is expected to be a valuable tool to evaluate the quality of engineered cartilage for commercial development in the future.
Subject(s)
Cartilage , Cell Survival , Chondrocytes , DNA , Extracellular Matrix , Glycosaminoglycans , In Vitro Techniques , Ioxaglic Acid , Polyglycolic Acid , Tissue EngineeringABSTRACT
In recent years, several kinds of cardiac progenitor cells have been identified and isolated from heart tissue. These cells showed differentiation potential into cardiomyocytes, smooth muscle cells, and endothelial cells in vitro and in vivo. Morphogenetic events are tightly regulated during development to determine cell destiny and reshape the embryonic lineage. In this study, we directly compared the characteristics of rat fetal cardiac progenitor cells (rFCPCs) isolated from the chamber formation stage at embryonic day 12 (E12) and at the septation stage of E15. Both kinds of rFCPCs expressed mesenchymal stem cell markers (CD105, CD73, and CD29) but not CD34 and CD45. The E12 rFCPCs expressed a high level of Oct4 compared to E15 until passage 5 and showed a steep decline of Nkx2.5 expression at passage 5. However, Nkx2.5 expression at E15 was maintained until passage 5 and Oct4 expression slightly increased at passage 5. We also detected an intense staining for Oct4 antibody in E12 heart tissue sections. The average doubling time of the E12 rFCPCs from passage 3 to passage 15 was about 5 hours longer than E15. These cells could also be induced into cardiomyocytes expressing α-MHC, cTnT, cTnC, and Cx43 under cardiomyogenic culture conditions and rFCPCs at E15 showed more intense staining of α-MHC than cells at E12 by immunocytochemistry. Taken together, our results show that developmental differences between E12 and E15 may influence their properties and differentiation. Furthermore those differences should be considered when deciding on the optimal cell source for cell replacement therapy in cardiovascular regeneration.
Subject(s)
Animals , Rats , Connexin 43 , Endothelial Cells , Heart , Immunohistochemistry , In Vitro Techniques , Mesenchymal Stem Cells , Myocytes, Cardiac , Myocytes, Smooth Muscle , Regeneration , Stem CellsABSTRACT
There are some errors in the published article. The authors would like to make corrections in the original version of the article
ABSTRACT
Treatment options for partial thickness cartilage defects are limited. The purpose of this study was to evaluate the efficacy of the chondrocyte-seeded cartilage extracellular matrix membrane in repairing partial thickness cartilage defects. First, the potential of the membrane as an effective cell carrier was investigated. Secondly, we have applied the chondrocyte-seeded membrane in an ex vivo, partial thickness defect model to analyze its repair potential. After culture of chondrocytes on the membrane in vitro, cell viability assay, cell seeding yield calculation and cell transfer assay were done. Cell carrying ability of the membrane was also tested by seeding different densities of cells. Partial defects were created on human cartilage tissue explants. Cell-seeded membranes were applied using a modified autologous chondrocyte implantation technique on the defects and implanted subcutaneously in nude mice for 2 and 4 weeks. In vitro data showed cell viability and seeding yield comparable to standard culture dishes. Time dependent cell transfer from the membrane was observed. Membranes supported various densities of cells. Ex vivo data showed hyaline-like cartilage tissue repair, integrated on the defect by 4 weeks. Overall, chondrocyte-seeded cartilage extracellular membranes may be an effective and feasible treatment strategy for the repair of partial thickness cartilage defects.
Subject(s)
Animals , Humans , Mice , Cartilage , Cell Survival , Chondrocytes , Extracellular Matrix , In Vitro Techniques , Lifting , Membranes , Mice, NudeABSTRACT
Stem cells and regenerative medicine are emerging and promising fields both in academic and industry points of views. They are currently under active investigation worldwide and their market size is expected to grow rapidly in the near future. The Korean government is also investing a huge amount of money on these fields to promote R&D and product commercialization. However, its technical maturity is still in its infant state and many hurdles should be resolved to accelerate technology to business. I can definitely say that we have to focus in the future on innovations in technology, regulations and reimbursement. In particular, the importance of translational research and clinical studies are of no doubt in the stem cells and regenerative medicine. I am going to deal with some of these issues in more detail in the main text.
Subject(s)
Humans , Infant , Commerce , Regenerative Medicine , Social Control, Formal , Stem Cells , Translational Research, BiomedicalABSTRACT
Mutations in the NF2 tumor suppressor gene cause neurofibromatosis type 2, an autosomal dominant inherited syndrome predisposed to the multiple tumors of the nervous system. Merlin, the NF2 gene product was reported to block Ras-mediated cell transformation and represses Ras-induced expression of cyclin D1. However, the potential mechanism underlying the anti-Ras function of merlin on the cyclin D1 is still unclear. In this study, we investigated whether merlin decreases Ha-ras-induced accumulation of cyclin D1 at the transcriptional level, and demonstrated that merlin suppressed Ras-induced cyclin D1 promoter activity mediated by the cyclic AMP-responsive element (CRE) in SK-N-BE (2) C neuroblastoma cells. Furthermore, we found that merlin attenuated active Ras and forskolin-induced CRE-driven promoter activity. These results suggest that the transcriptional repression of the cyclin D1 expression by merlin may contribute to the inhibition of Ras-induced cell proliferation