Publications by authors named "Bo K Sun"

It has previously been demonstrated that hypoxia has diverse stimulatory effects on adipose‑derived stem cells (ASCs), however, metabolic responses under hypoxia remain to be elucidated. Thus, the present study aimed to investigate the glucose uptake and metabolism of ASCs under hypoxic conditions, and to identify the underlying molecular mechanisms. ASCs were cultured in 1% oxygen, and experiments were conducted in vitro.

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Background: The objectives of this study were to develop stable cyclosporine A (CsA) ophthalmic micelle solutions for dry-eye syndrome and evaluate their physicochemical properties and therapeutic efficacy.

Materials And Methods: CsA-micelle solutions (MS-CsA) were created by a simple method with Cremophor EL, ethanol, and phosphate buffer. We investigated the particle size, pH, and osmolarity.

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Fluoxetine was originally developed as an antidepressant, but it has also been used to treat obesity. Although the anti-appetite effect of fluoxetine is well-documented, its potential effects on human adipose-derived stem cells (ASCs) or mature adipocytes have not been investigated. Therefore, we investigated the mechanisms underlying the inhibitory effects of fluoxetine on the proliferation of ASCs.

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Objectives: The objectives of this study were to prepare cyclosporin A (CsA)-containing proliposomes using the supercritical antisolvent (SAS) process and the conventional thin film method for the comparative study of proliposomal formulations and to evaluate the physicochemical properties of these proliposomes.

Methods: CsA-containing proliposomes were prepared by the SAS process and the conventional film method, composed of natural and synthetic phospholipids. We investigated particle size, polydispersity index, and zeta potential of CsA-containing proliposomes.

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Background: The objective of this study was to compare the efficacy of cyclosporin (CsA)-encapsulated liposomes with the commercially available CsA emulsion (Restasis) for the treatment of dry eye syndrome in rabbits.

Methods: Liposomes containing CsA were prepared by the supercritical fluid (SCF) method consisted of phosphatidylcholine from soybean (SCF-S100) and egg lecithins (SCF-EPCS). An in vitro permeation study was carried out using artificial cellulose membrane in Franz diffusion cells.

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Previously, we showed that mitogen-activated protein kinase/extracellular signal-related kinase 4 (MEKK4) is responsible for p38 activation and that its activation during tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment also increases the catalytic activity of Akt. Here, we further investigated how the TRAIL-induced MEKK4/p38/heat shock protein (HSP27)/Akt survival network is modulated by the Src/c-Cbl interacting protein of 85kDa (CIN85)/c-Cbl complex. TRAIL-induced activation of Akt catalytic activity and phosphorylation were highly correlated with p38/HSP27 phosphorylation, whereas the phosphorylation of p38/HSP27 increased further during incubation with curcumin and TRAIL, which caused significant apoptotic cell death.

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The combination of curcumin and TRAIL and their role in enhancing apoptotic cell death has been reported by many studies. However, the exact molecular mechanism of apoptosis mediated by curcumin and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is not yet completely understood. In this study, we observed a close connection between dephosphorylated Akt and an increase in phosphorylated heat shock protein 27 (HSP27) during combined treatment with curcumin and TRAIL.

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The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to activate mitogen-activated protein kinases (MAPKs) depending on caspase and mammalian sterile 20-like kinase 1 activations. However, the upstream molecule of MAPKs has not yet been identified. The mitogen-activated protein kinase kinase 1 (MEKK1) and the apoptosis signal-regulating kinase 1 (ASK1) are considered to be possible candidates for the action of MAPKKKs induced by TRAIL and the possibility of reactive oxygen species involvement has also been investigated.

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We previously observed that TRAIL induces acquired TRAIL resistance coinciding with increased Akt phosphorylation brought about by the Src-PI3K-Akt signaling pathways and mediated by c-Cbl. c-Cbl, a ubiquitously expressed cytoplasmic adaptor protein, is simultaneously involved in the rapid degradation of TRAIL receptors and Akt phosphorylation during TRAIL treatment. Here, we show that Akt phosphorylation is not exclusively responsible for acquired TRAIL resistance.

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We have previously observed that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) induces acquired TRAIL resistance by increasing Akt phosphorylation and Bcl-xL expression. In this study, we report that Src, c-Cbl, and PI3K are involved in the phosphorylation of Akt during TRAIL treatment. Data from immunoprecipitation and immunoblotting assay reveal that Src interacts with c-Cbl and PI3K.

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This study examined the efficacy of poly(NiPAAm-co-AAc) as an injectable drug delivery vehicle and a cell therapeutic agent in the form of a supporting matrix for the chondrogenic differentiation of rabbit chondrocytes. The hydrogel constructs, which consisted of embedded cells co-encapsulating dexamethasone (Dex) and TGF beta-1 or unloaded Dex, were used as controls to determine the effects of Dex and TGF beta-1 on chondrogenic differentiation. The level of Dex and TGF beta-1 released was monitored using a bioimaging method.

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Biodegradable elastic hydrogel scaffolds based on hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(epsilon-caprolactone) (PCL) were fabricated and investigated as a delivery vehicle of rabbit chondrocytes for the formation of neocartilage. The diacrylated forms of PEG and PCL were used as building blocks to prepare a series of hydrogel scaffolds with different block compositions and, thus, different physico-chemical properties. The porous hydrogel scaffolds were prepared by using the salt leaching method that is generally used for the creation of porous scaffolds, and their in vitro cell interactions were examined using chondrocytes.

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To use nano-structured materials as a novel cell therapeutic agent, we have devised a novel method for the fabrication of nano-scaled 3D scaffolds consisting of heparin/poly(ethylenimine) (PEI) nanoparticles in a thermo-reversible hydrogel, attached via a layer-by-layer system. Bioassay results showed significant difference in DNA amount between groups. Specifically, groups with heparin/PEI nanoparticles had almost twice the glycosaminoglycan content per construct starting at day 7 as compared to controls.

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The effects of inducible materials (dexamethasone and ascorbate) on chondrogenic differentiation of rabbit chondrocytes have been examined. A hydrogel construct containing dexamethasone and ascorbate up-regulated gene expression of the cartilage matrix component of collagen to give three times the collagen content per construct at day 56 as compared to controls. Alcian Blue and Safranin-O staining revealed that these constructs also had formed more hyaline cartilage than other hydrogel constructs.

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This study evaluated the potential of using poly(NiPAAm-co-AAc) as an injectable drug delivery carrier and a cell therapeutic agent in the form of a supporting matrix for the chondrogenic differentiation of rabbit chondrocytes. In particular, rabbit chondrocytes were embedded in hydrogels containing a combination of ascorbate and transforming growth factor beta-3 (TGF beta-3). Hydrogel constructs containing embedded cells either without ascorbate or a combination of ascorbate and TGF beta-3 were used as controls to determine the effects of ascorbate and TGF beta-3 on chondrogenic differentiation.

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The aim of this study was to assess the efficacy of poly(NiPAAm-co-AAc) blended with hyaluronic acid (HA) as an injectable cell vehicle and a cell therapeutic agent in the form of a supporting matrix for the chondrogenic differentiation of rabbit chondrocytes. Specially, rabbit chondrocytes were embedded in blended hydrogels co-encapsulation with dexamethasone (Dex) and growth factors for enhancing the chondrogenic differentiation. Blended hydrogel constructs consisting of embedded cells co-encapsulating Dex and TGF beta-3 or unloaded Dex and sTGF beta-3 served as controls to assess the effects of Dex on chondrogenic differentiation.

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The aim of this study was to assess the efficacy of ectopic bone formation in a three-dimensional hybrid scaffold in combination with hydroxyapatite (HA) and poly(NiPAAm-co-AAc) as an injectable vehicle in the form of a supporting matrix for the osteogenic differentiation of rabbit mesenchymal stem cells (MSCs). Osteogenic differentiation of MSCs in the hybrid scaffold was greatly influenced by the addition of growth factors. When the osteoinduction activity of hybrid scaffold was studied following implantation into the back subcutis of nude mouse in terms of histological and biochemical examinations, significantly homogeneous bone formation was histologically observed throughout the hybrid scaffolds containing growth factor (BMP-2: bone morphogenic protein-2).

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In this study, a hydrogel composite, based on the thermo-reversible hydrogel of p(NiPAAm-co-AAc) and hyaluronic acid (HA) was used as an injectable cell and growth factor carrier for cartilage tissue engineering applications. Rabbit chondrocytes were embedded in blended hydrogel composites co-encapsulated with the transforming growth factor beta-3 (TGFbeta-3). The blended hydrogel with the embedded chondrocytes and HA co-encapsulating unloaded growth factors and those with the thermo-reversible hydrogel were used as the controls to examine the effects of TGFbeta-3 on neocartilage formation.

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The aim of this study was to assess the efficacy of poly(N-isopropylacrylamide-co-acrylic acid) (p(NiPAAm-co-AAc)) as an injectable drug delivery vehicle and a cell therapeutic agent in the form of a supporting matrix for the chondrogenic differentiation of rabbit chondrocytes. The p(NiPAAm-co-AAc) hydrogel itself without specific differentiation-inducing drugs was used as a control in order to determine the effects of these materials on chondrogenic differentiation. The level of cartilage associated extracellular matrix (ECM) proteins was examined by immunohistochemical staining for collagen type II as well as Safranin-O and Alcian blue (GAG) staining.

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Rosiglitazone (RGTZ) has protective effect against various types of injury. This study was performed to evaluate the effect of RGTZ on pancreatic and renal injury caused by cyclosporine (CsA). CsA (15 mg/kg) and RGTZ (3 mg/kg) were administered alone and together to the rats for 28 days.

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Background: Statins and angiotensin II type I receptor blockers have synergistic effects on vascular smooth-muscle-cell proliferation and the progression of renal diseases. We evaluated whether combined treatment with losartan (LSRT) and pravastatin (PRVT) affords superior protection compared with their respective monotherapies in treating chronic cyclosporine (CsA)-induced nephropathy in rats.

Methods: Rats maintained on a low salt diet were given vehicle, CsA (15 mg/kg), CsA and LSRT (10 mg/kg), CsA and PRVT (5 mg/kg), or a combination of CsA, LSRT, and PRVT for 28 days.

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Background: There is growing evidence of a role of the immune system in the pathophysiology of ischemia-reperfusion (I/R) injury, but the influence of I/R injury on innate immunity is still undetermined.

Methods: Sprague-Dawley rats were used. I/R injury was induced by clamping both renal arteries for 45 min, and the rats were killed 1, 3, 5, and 7 days later.

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Background/aim: Induction of heat shock protein 70 (HSP70) is important in the tolerance of subsequent ischemia-reperfusion (I/R) injury. The aim of this study was to evaluate the effect of HSP70 induction by 1,25-dihydroxyvitamin D3 (VD3) on subsequent I/R injury in rats.

Methods: HSP70 was induced in Sprague-Dawley rats by VD3 treatment for 7 days, and the effect of VD3 pretreatment on subsequent I/R injury was evaluated in terms of renal function, tubular necrosis score, tumor necrosis factor alpha mRNA expression, mitogen-activated protein kinase expression, and proliferating cell nuclear antigen expression.

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Background: We recently demonstrated that upregulation of the transforming growth factor (TGF)-beta1 inducible gene-h3 (betaig-h3) is associated with tubulointerstitial fibrosis (TIF) in a rat model of chronic cyclosporine A (CsA) nephrotoxicity. This study investigated the association between betaig-h3 expression and TIF during losartan treatment in this model.

Methods: Adult Sprague-Dawley rats kept on a salt-depleted diet (0.

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Cyclosporine (CsA) has improved patient and graft survival rates following solid-organ transplantation and has been increasingly applied with significant clinical benefits in the management of autoimmune diseases. However, the clinical use of CsA is often limited by acute and chronic nephrotoxicity, which remains a major problem. Acute nephrotoxicity depends on the dosage of CsA and seems to be caused by a reduction in renal blood flow related to afferent arteriolar vasoconstriction.

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