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The R2R3‐type protein IbMYB1 is a key regulator of anthocyanin biosynthesis in the storage roots of sweet potato [Ipomoea batatas (L.) Lam]. Previously, we demonstrated that IbMYB1 expression stimulated anthocyanin pigmentation in tobacco leaves and Arabidopsis. Here, we generated dual‐pigmented transgenic sweet potato plants that accumulated high levels of both anthocyanins and carotenoids in a single sweet potato storage root. An orange‐fleshed cultivar with high carotenoid levels was transformed with the IbMYB1 gene under the control of either the storage root‐specific sporamin 1 (SPO1) promoter or the oxidative stress‐inducible peroxidase anionic 2 (SWPA2) promoter. The SPO1‐MYB transgenic lines exhibited higher anthocyanin levels in storage roots than empty vector control (EV) or SWPA2‐MYB plants, but carotenoid content was unchanged. SWPA2‐MYB transgenic lines exhibited higher levels of both anthocyanin and carotenoids than EV plants. Analysis of hydrolyzed anthocyanin extracts indicated that cyanidin and peonidin predominated in both overexpression lines. Quantitative reverse transcription‐polymerase chain reaction analysis demonstrated that IbMYB1 expression in both IbMYB1 transgenic lines strongly induced the upregulation of several genes in the anthocyanin biosynthetic pathway, whereas the expression of carotenoid biosynthetic pathway genes varied between transgenic lines. Increased anthocyanin levels in transgenic plants also promoted the elevation of proanthocyanidin and total phenolic levels in fresh storage roots. Consequently, all IbMYB1 transgenic plants displayed much higher antioxidant activities than EV plants. In field cultivations, storage root yields varied between the transgenic lines. Taken together, our results indicate that overexpression of IbMYB1 is a highly promising strategy for the generation of transgenic plants with enhanced antioxidant capacity. [ABSTRACT FROM AUTHOR]

Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are a heterogeneous population of cells that differ in size and morphology. BM-MSCs become committed to the osteogenic lineage as senescence approaches and lose multipotency. Nevertheless, little is known about the effects of cell-cell interaction between different populations on stemness loss and lineage commitment. The current study aimed to identify mechanisms by which cell-cell interactions between heterogeneous BM-MSCs affect stemness and lineage commitment of multipotent subpopulation. The lineage commitment of primitive multipotent cells was strongly induced in the presence of cytokines secreted by senescent-like cells in a cell culture insert system. Senescent-like cells secreted higher levels of interleukin-6 (IL-6) than primitive multipotent cells in a human cytokine array. IL-6 induced the lineage commitment and stemness loss in multipotent cells by decreasing Sox2 expression. Furthermore, we confirmed that IL-6 decreased the transcriptional activity ofSox2 through up-regulation of Runx2 and Dlx5. We suggest a mechanism by which IL-6 modulates the expression of Sox2, resulting in decreased multipotency and causing primitive multipotent cells to undergo osteogenic lineage commitment. This is the first study to identify mechanisms in which the cell-cell interactions between the different populations play important roles in the stemness loss and lineage commitment of multipotent populations. [ABSTRACT FROM AUTHOR]

Lycopene ϵ-cyclase (LCY-ϵ) is involved in the first step of the α-branch synthesis pathway of carotenoids from lycopene in plants. In this study, to enhance carotenoid synthesis via the β-branch-specific pathway [which yields β-carotene and abscisic acid (ABA)] in sweetpotato, the expression of IbLCY-ϵ was downregulated by RNAi (RNA interference) technology. The RNAi- IbLCY-ϵ vector was constructed using a partial cDNA of sweetpotato LCY-ϵ isolated from the storage root and introduced into cultured sweetpotato cells by Agrobacterium-mediated transformation. Both semi-quantitative Reverse transcription polymerase chain reaction (RT-PCR) of carotenoid biosynthesis genes and high-performance liquid chromatography (HPLC) analysis of the metabolites in transgenic calli, in which the LCY-ϵ gene was silenced, showed the activation of β-branch carotenoids and its related genes. In the transgenic calli, the β-carotene content was approximately 21-fold higher than in control calli, whereas the lutein content of the transgenic calli was reduced to levels undetectable by HPLC. Similarly, expression of the RNAi- IbLCY-ϵ transgene resulted in a twofold increase in ABA content compared to control calli. The transgenic calli showed significant tolerance of 200 m M NaCl. Furthermore, both the β-branch carotenoids content and the expression levels of various branch-specific genes were higher under salt stress than in control calli. These results suggest that, in sweetpotato, downregulation of the ϵ-cyclization of lycopene increases carotenoid synthesis via the β-branch-specific pathway and may positively regulate cellular defenses against salt-mediated oxidative stress. [ABSTRACT FROM AUTHOR]

Oxidative stress is a major threat for plants exposed to various environmental stresses. Previous studies found that transgenic potato plants expressing both copper zinc superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) (referred to as SSA plants), or nucleoside diphosphate kinase 2 (NDPK2) (SN plants), showed enhanced tolerance to methyl viologen (MV)-induced oxidative stress and high temperature. This study aimed to develop transgenic plants that were more tolerant of oxidative stress by introducing the NDPK2 gene into SSA potato plants under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter to create SSAN plants. SSAN leaf discs and whole plants showed enhanced tolerance to MV, as compared to SSA, SN or non-transgenic (NT) plants. SSAN plants sprayed with 400 µM MV exhibited about 53 and 83% less visible damage than did SSA and SN plants, respectively. The expression levels of the CuZnSOD, APX and NDPK2 genes in SSAN plants following MV treatment correlated well with MV tolerance. SOD, APX, NDPK and catalase antioxidant enzyme activities were also increased in MV-treated SSAN plants. In addition, SSAN plants were more tolerant to high temperature stress at 42°C, exhibiting a 6.2% reduction in photosynthetic activity as compared to plants grown at 25°C. In contrast, the photosynthetic activities of SN and SSA plants decreased by 50 and 18%, respectively. These results indicate that the simultaneous overexpression of CuZnSOD, APX and NDPK2 is more effective than single or double transgene expression for developing plants with enhanced tolerance to various environmental stresses. [ABSTRACT FROM AUTHOR]

MYB transcription factors play important roles in transcriptional regulation of many secondary metabolites including anthocyanins. We cloned the R2R3-MYB type IbMYB1 complementary DNAs from the purple-fleshed sweet potato ( Ipomoea batatas L. cv Sinzami) and investigated the expression patterns of IbMYB1 gene with IbMYB1a and IbMYB1b splice variants in leaf and root tissues of various sweet potato cultivars by reverse transcription-polymerase chain reaction. The transcripts of IbMYB1 were predominantly expressed in the purple-fleshed storage roots and they were also detectable in the leaf tissues accumulating anthocyanin pigments. In addition, transcript levels of IbMYB1 gene were up-regulated by treatment with methyl jasmonate or salicylic acid in leaf and root tissues of cv. White Star. To set up the intragenic vector system in sweet potato, we first evaluated the utilization of the IbMYB1 gene as a visible selectable marker. The IbMYB1a was transiently expressed in tobacco leaves under the control of a constitutive cauliflower mosaic virus 35S promoter, a root-specific and sucrose-inducible sporamin promoter, and an oxidative stress-inducible sweet potato anionic peroxidase2 promoter. We also showed that overexpression of IbMYB1a induced massive anthocyanin pigmentation in tobacco leaves and up-regulated the transcript levels of the structural genes in anthocyanin biosynthetic pathway. Furthermore, high-performance liquid chromatography analysis revealed that the expression of IbMYB1a led to production of cyanidin as a major core molecule of anthocyanidins in tobacco leaves. These results suggest that the IbMYB1 gene can be applicable to a visible marker for sweet potato transformation with intragenic vectors, as well as the production of anthocyanin as important nutritive value in other plant species. [ABSTRACT FROM AUTHOR]

Plants synthesize compatible solutes such as glycinebetaine (GB) in response to abiotic stresses. To evaluate the synergistic and protective effect of GB, transgenic potato plants expressing superoxide dismutase (SOD) and ascorbate peroxidase (APX) targeting to chloroplasts (referred to as SSA plants) were retransformed with a bacterial choline oxidase ( codA) gene to synthesize GB in chloroplast in naturally occurring non-accumulator potato plants (including SSA) under the control of the stress-inducible SWPA2 promoter (referred to as SSAC plants). GB accumulation resulted in enhanced protection of these SSAC plants and lower levels of H2O2 compared with SSA and non-transgenic (NT) plants after methyl viologen (MV)-mediated oxidative stress. Additionally, SSAC plants demonstrated synergistically enhanced tolerance to salt and drought stresses at the whole-plant level. GB accumulation in SSAC plants helped to maintain higher activities of SOD, APX and catalase following oxidative, salt and drought stress treatments than is observed in SSA and NT plants. Conclusively, GB accumulation in SSAC plants along with overexpression of antioxidant genes rendered the plants tolerant to multiple environmental stresses in a synergistic fashion. [ABSTRACT FROM AUTHOR]

•Plant receptor-like kinases belong to a large gene family. The Capsicum annuum receptor-like kinase 1 ( CaRLK1) gene encodes a transmembrane protein with a cytoplasmic kinase domain and an extracellular domain. •The CaRLK1 extracellular domain (ECD)–green fluorescent protein (GFP) fusion protein was targeted to the plasma membrane, and the kinase domain of the CaRLK1 protein exhibited autophosphorylation activity. CaRLK1 transcripts were more strongly induced in treatment with Xag8ra than in treatment with Xag8-13. Furthermore, infection with incompatible Xanthomonas campestris pv. vesicatoria race 3 induced expression of CaRLK1 more strongly than in the compatible interaction. •Cell death caused by both a disease-forming and an HR-inducing pathogen was delayed in the CaRLK1-transgenic plants. Ectopic expression of CaRLK1 also induced transcripts of the lesion stimulating disease ( LSD) gene, a negative regulator of cell death. Respiratory burst oxidase homolog ( RBOH) genes were up-regulated in the transgenic plants compared with the wild type, as the concentration of the superoxide anion was increased. In contrast, the concentration of H2O2 did not differ between the transgenic and wild-type plants. •These results support the theory that the suppression of plant cell death by CaRLK1 is associated with consistent production of the superoxide anion and induction of the RBOH genes and the LSD gene, but not with the concentration of H2O2. Thus, CaRLK1 may be a receptor of an as yet unidentified pathogen molecular pattern and may function as a negative regulator of plant cell death. [ABSTRACT FROM AUTHOR]

Previously, the swpa4 peroxidase gene has been shown to be inducible by a variety of abiotic stresses and pathogenic infections in sweet potato ( Ipomoea batatas). To elucidate its regulatory mechanism at the transcriptional level under various stress conditions, we isolated and characterized the promoter region (2374 bp) of swpa4 (referred to as SWPA4). We performed a transient expression assay in tobacco protoplasts with deletions from the 5′-end of SWPA4 promoter fused to the β-glucuronidase (GUS) reporter gene. The −1408 and −374 bp deletions relative to the transcription start site (+1) showed 8 and 4.5 times higher GUS expression than the cauliflower mosaic virus 35S promoter, respectively. In addition, transgenic tobacco plants expressing GUS under the control of −2374, −1408 or −374 bp region of SWPA4 promoter were generated and studied in various tissues under abiotic stresses and pathogen infection. Gel mobility shift assays revealed that nuclear proteins from sweet potato cultured cells specifically interacted with 60-bp fragment (−178/−118) in −374 bp promoter region. In silico analysis indicated that four kinds of cis-acting regulatory sequences, reactive oxygen species-related element activator protein 1 (AP1), CCAAT/enhancer-binding protein alpha element, ethylene-responsive element (ERE) and heat-shock element, are present in the −60 bp region (−178/−118), suggesting that the −60 bp region might be associated with stress inducibility of the SWPA4 promoter. [ABSTRACT FROM AUTHOR]

Type II collagen is a major protein that maintains biological and mechanical characteristics in articular cartilage. Focal adhesion kinase (FAK) is known to play a central role in integrin signaling of cell–extracellular matrix (ECM) interactions, and chondrocyte–type II collagen interactions are very important for cartilage homeostasis. In this study, we focused on phosphorylation of FAK and MAP kinase in chondrocyte–type II collagen interaction and dedifferentiation, and the effects of FAK knockdown on chondrocyte-specific gene expression and cell proliferation were determined. The addition of exogenous type II collagen to chondrocytes increased levels of tyrosine phosphorylation, p-FAKY397, and p-ERK1/2. In contrast, expression levels of p-FAKY397 and p-ERK1/2, but not p-Smad2/3, were decreased in dedifferentiated chondrocytes with loss of type II collagen expression. Type II collagen expression was significantly increased when dedifferentiated chondrocytes were transferred to alginate beads with TGF-β1 or type II collagen, but transfected cells with small interfering RNA for FAK (FAK-siRNA) inhibited mRNA expression of type II collagen and SOX-6 compared to the control. These FAK-siRNA-transfected cells could not recover type II collagen even in the presence of TGF-β1 or type II collagen in alginate beads culture. We also found that FAK-siRNA-transfected cells decreased cell proliferation rate, but there was no effect on glycosaminoglycans (GAGs) secretion. We suggest that FAK is essentially required in chondrocyte communication with type II collagen by regulating type II collagen expression and cell proliferation. J. Cell. Physiol. 218: 623–630, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

This study examined the synergistic effect of high glucose levels and ANG II on proliferation and its related signal pathways using mouse embryonic stem (ES) cells. The combined use of a high glucose concentration (25 mM) and ANG II increased the level of [3H]thymidine/BrdU incorporation, and the number of cells compared with either treatment alone. Each treatment with high glucose or ANG II increased the cell population in the S phase compared with control, and the combined treatment of a high glucose concentration and ANG II significantly increased the number of cells in the S phase according to FACS analysis. Moreover, the high glucose-induced increase in [3H]thymidine incorporation was blocked by inhibiting the ANG II type 1 (AT1) receptor. The combined high glucose and ANG II significantly increased the STAT3 phosphorylation compared with high glucose or ANG II alone. ANG II stimulated the influx of Ca2+ in 25 mM glucose compared with 5 mM glucose. High glucose levels increase the level of PKC α, ℇ, and ζ translocation from the cytosol to the membrane fraction. In an examination of other signal pathways, the combined treatment significantly increased the level of p44/42, p38 MAPKs phosphorylation compared with either treatment alone. Indeed, the combined treatment increased the mRNA expression level of the protooncogenes and cell cycle regulatory proteins. In conclusion, the combined treatment of a high glucose concentration and ANG II had a synergistic effect in stimulating mouse ES cell proliferation through the Ca2+/PKC, MAPKs, and the AT1 receptor. J. Cell. Physiol. 215: 374–382, 2008. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Effect of angiotensin II (ANG II) on mouse embryonic stem (ES) cell proliferation was examined. ANG II increased [3H] thymidine incorporation in a time- (>4 h) and dose- (>10-9 M) dependent manner. The ANG II-induced increase in [3H] thymidine incorporation was blocked by inhibition of ANG II type 1 (AT1) receptor but not by ANG II type 2 (AT2) receptor, and AT1 receptor was expressed. ANG II increased inositol phosphates formation and [Ca2+]i, and translocated PKC α, δ, and ζ to the membrane fraction. Consequently, the inhibition of PLC/PKC suppressed ANG II-induced increase in [3H] thymidine incorporation. The inhibition of EGF receptor kinase or tyrosine kinase prevented ANG II-induced increase in [3H] thymidine incorporation. ANG II phosphorylated EGF receptor and increased Akt, mTOR, and p70S6K1 phosphorylation blocked by AG 1478 (EGF receptor kinase blocker). ANG II-induced increase in [3H] thymidine incorporation was blocked by the inhibition of p44/42 MAPKs but not by p38 MAPK inhibition. Indeed, ANG II phosphorylated p44/42 MAPKs, which was prevented by the inhibition of the PKC and AT1 receptor. ANG II increased c-fos, c-jun, and c-myc levels. ANG II also increased the protein levels of cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 2, and CDK4 but decreased the p21cip1/waf1 and p27kip1, CDK inhibitory proteins. These proteins were blocked by the inhibition of AT1 receptor, PLC/PKC, p44/42 MAPKs, EGF receptor, or tyrosine kinase. In conclusion, ANG II-stimulated DNA synthesis is mediated by ANG II receptor-dependent Ca2+/PKC and EGF receptor-dependent PI3K/Akt/mTOR/p70S6K1 signal pathways in mouse ES cells. J. Cell. Physiol. 211: 618–629, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Nerve growth factor (NGF) is known to promote the axonal regeneration in injured nerve system. Delivery of NGF for a long period in a controlled manner may enhance the regeneration efficacy. In this study, we investigated whether NGF can be released from fibrin gel for a long period in a controlled manner. We also investigated whether sustained delivery of NGF using fibrin gel can enhance the efficacy of NGF in vitro. The addition of heparin to fibrin gel decreased the rate of NGF release from the fibrin gel. As the concentrations of thrombin and fibrinogen in fibrin gel increased, the NGF release rate decreased significantly, and the initial release burst decreased. NGF was released for up to 14 days in vitro. The bioactivity of NGF released from fibrin gel was assessed by morphological changes of pheochromocytoma (PC12) cells cultured in the presence of NGF‐containing fibrin gel. NGF released from fibrin gel exhibited significantly higher degrees of PC12 cell viability and differentiation than NGF added in a free form daily into the culture medium. This study demonstrates that fibrin gel can release NGF in a sustained, controlled manner and in a bioactive form. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007 [ABSTRACT FROM AUTHOR]

This study examined the effects of high glucose on cell proliferation and its related signal pathways using mouse embryonic stem (ES) cells. Here, we showed that high glucose level significantly increased [3H]thymidine incorporation, BrdU incorporation, the number of cells, [3H]leucine, and [3H]proline incorporation in a time-(>3 hr) and dose-(>25 mM) dependent manner. Moreover, high glucose level increased the cellular reactive oxygen species (ROS), Akt, and mitogen-activated protein kinases (MAPKs) phosphorylation. Subsequently, these signaling molecules involved in high glucose-induced increase of [3H]thymidine incorporation. High glucose level also increased cyclin D1, cyclin E, cyclin-dependent kinase (CDK) 2, and CDK 4 protein levels, which is cell cycle regulatory proteins acting in G1–S phase of cell cycle. Inhibition of phosphatidylinositol 3-kinase (PI3-K) (LY 294002: PI3-kinase inhibitor, 10-6 M), Akt (Akt inhibitor, 10-5 M), and p44/42 MAPKs (PD 98059: MEK inhibitor, 10-5 M) decreased these proteins. High glucose level phosphorylated the RB protein, which was decreased by inhibition of PI3-K and Akt. In conclusion, high glucose level stimulates mouse ES cell proliferation via the PI3-K/Akt and MAPKs pathways. J. Cell. Physiol. 209: 94–102, 2006. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Here we report inhibition of phospholipase C-β1 (PLC-β1)-mediated signaling by post-translational glycosylation with β-N-acetylglucosamine (O-GlcNAc modification). In C2C12 myoblasts, isoform-specific knock-down experiments using siRNA showed that activation of bradykinin (BK) receptor led to stimulation of PLC-β1 and subsequent intracellular Ca2+ mobilization. In C2C12 myotubes, O-GlcNAc modification of PLC-β1 was markedly enhanced in response to treatment with glucosamine (GlcNH2), an inhibitor of O-GlcNAase (PUGNAc) and hyperglycemia. This was associated with more than 50% inhibition of intracellular production of IP3 and Ca2+ mobilization in response to BK. Since the abundance of PLC-β1 remained unchanged, these data suggest that O-GlcNAc modification of PLC-β1 led to inhibition of its activity. Moreover, glucose uptake stimulated by BK was significantly blunted by treatment with PUGNAc. These data support the notion that O-GlcNAc modification negatively modulates the activity of PLC-β1. J. Cell. Physiol. © 2006 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Endogenous opioid peptides, found in the central and peripheral nervous systems, perform neuromodulatory roles, and display a wide range of functional and pharmacological properties in vitro and in vivo. In this study, we investigated the effects of prodynorphin gene products on intracellular signaling events and cell survival in rat pheochromocytoma PC12 cells. Leumorphin, but not other prodynorphin gene products including dynorphin A, β-neoendorphin and rimorphin (dynorphin B), increased cell viability in PC12 cells. The cytoprotective effect of leumorphin was dependent on the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways, but was insensitive to both naloxone, a general antagonist of the opioid receptor, and nor-binaltorphimine, a specific antagonist of the kappa opioid receptor. Moreover, a competition-binding assay clearly revealed that leumorphin had another binding site(s) in addition to that for the kappa opioid receptor. Interestingly, leumorphin induced activation of the epidermal growth factor receptor via a Src-dependent mechanism, which was proved to be responsible for the increased survival response. Flow cytometric and microscopic analysis showed that leumorphin rescued cells from serum deprivation-induced apoptosis. Collectively, we suggest that leumorphin prevents apoptosis via epidermal growth factor receptor-mediated activation of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways, which occur independent of the kappa opioid receptor. [ABSTRACT FROM AUTHOR]

Virtual reality (VR) therapy is a new, neurorehabilitation intervention aimed at enhancing motor performance in children with hemiparetic cerebral palsy (CP). This case report investigated the effects of VR therapy on cortical reorganization and associated motor function in an 8-year-old male with hemiparetic CP. Cortical activation and associated motor development were measured before and after VR therapy using functional magnetic resonance imaging (fMRI) and standardized motor tests. Before VR therapy, the bilateral primary sensorimotor cortices (SMCs) and ipsilateral supplementary motor area (SMA) were predominantly activated during affected elbow movement. After VR therapy, the altered activations disappeared and the contralateral SMC was activated. This neuroplastic change was associated with enhanced functional motor skills including reaching, self-feeding, and dressing. These functions were not possible before the intervention. To our knowledge, this is the first fMRI study in the literature that provides evidence for neuroplasticity after VR therapy in a child with hemiparetic CP. [ABSTRACT FROM AUTHOR]

Cortistatin is a neuropeptide relative of somatostatin. Cortistatin is known to activate the five somatostatin receptors and share relevant properties with somatostatin. However, the functions of cortistatin distinct from somatostatin remain unknown except for induction of slow-wave sleep, reduction of locomotor activity. Here we showed that cortistatin could induce neuronal differentiation in PC12 cells. Cortistatin induced neurite outgrowth in the presence of retinoic acid, another neutropic factor. Actually, the number of cells with neurite was increased about two times by cortistatin and retinoic acid compared with retinoic acid only. On the other hand, retinoic acid increased the expression of cortistatin receptors. The expression of cortistatin receptors was significantly increased from 1 hr to 4 hr after retinoic acid treatment, suggesting that increased expression of cortistatin receptors triggers intracellular signaling involved in neurite outgrowth. Taken together, cortistatin might be a new factor of neuronal differentiation. In addition, our finding may lead to a better understanding the relationship between neuropeptide and retinoic acid in neuronal development. [ABSTRACT FROM AUTHOR]