共查询到20条相似文献,搜索用时 31 毫秒
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Myelin basic protein (MBP) and two peptides derived from MBP (MBP1–44 and MBP152–167) stimulated Schwann cell (SC) proliferation in a cAMP-mediated process. The two mitogenic regions of MBP did not compete with one another for binding to SC suggesting a distinctive SC receptor for each mitogenic peptide. Neutralizing antibodies to the fibroblast growth factor receptor blocked the mitogenic effect of the myelin-related SC mitogen found in the supernatant of myelin-fed macrophages. The binding of 125I-MBP to Schwann cells was specifically inhibited by basic fibroblast growth factor (bFGF) and conversely the binding of 125I-bFGF was competitively inhibited by MBP. These data suggested that the mitogenic effect of one MBP peptide was mediated by a bFGF receptor. The binding of MBP to ganglioside GM1 and the ability of MBP peptides containing homology to the B subunit of cholera toxin (which binds ganglioside GM1) to compete for the binding of a mitogenic peptide (MBP1–44) to SC, identified ganglioside GM1 as a second SC receptor. Based on these results, we conclude that MBP1–44 and MBP152–167 associate with ganglioside GM1 and the bFGF receptor respectively to stimulate SC mitosis. 相似文献
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Jun Li Manzhu Zhao Yingying Wang Mengjie Shen Shuai Wang Mengying Tang Meng Li Yuting Luo Kun Yang Xiujie Wen 《Journal of cellular and molecular medicine》2020,24(13):7563-7575
Human periodontal ligament stem cells (hPDLSCs) are a promising source in regenerative medicine. Due to the complexity and heterogeneity of hPDLSCs, it is critical to isolate homogeneous hPDLSCs with high regenerative potential. In this study, p75 neurotrophin receptor (p75NTR) was used to isolate p75NTR+ and p75NTR? hPDLSCs by fluorescence‐activated cell sorting. Differences in osteogenic differentiation among p75NTR+, p75NTR? and unsorted hPDLSCs were observed. Differential gene expression profiles between p75NTR+ and p75NTR? hPDLSCs were analysed by RNA sequencing. α1 Integrin (ITGA1) small interfering RNA and ITGA1‐overexpressing adenovirus were used to transfect p75NTR+ and p75NTR? hPDLSCs. The results showed that p75NTR+ hPDLSCs demonstrated superior osteogenic capacity than p75NTR? and unsorted hPDLSCs. Differentially expressed genes between p75NTR+ and p75NTR? hPDLSCs were highly involved in the extracellular matrix‐receptor interaction signalling pathway, and p75NTR+ hPDLSCs expressed higher ITGA1 levels than p75NTR? hPDLSCs. ITGA1 silencing inhibited the osteogenic differentiation of p75NTR+ hPDLSCs, while ITGA1 overexpression enhanced the osteogenic differentiation of p75NTR? hPDLSCs . These findings indicate that p75NTR optimizes the osteogenic potential of hPDLSCs by up‐regulating ITGA1 expression, suggesting that p75NTR can be used as a novel cell surface marker to identify and purify hPDLSCs to promote their applications in regenerative medicine. 相似文献
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Dichloroacetate (DCA) is an investigational drug for genetic mitochondrial diseases whose use has been mitigated by reversible peripheral neuropathy. We investigated the mechanism of DCA neurotoxicity using cultured rat Schwann cells (SCs) and dorsal root ganglia (DRG) neurons. Myelinating SC-DRG neuron co-cultures, isolated SCs and DRG neurons were exposed to 1-20 mm DCA for up to 12 days. In myelinating co-cultures, DCA caused a dose- and exposure-dependent decrease of myelination, as determined by immunolabeling and immunoblotting for myelin basic protein (MBP), protein zero (P0), myelin-associated glycoprotein (MAG) and peripheral myelin protein 22 (PMP22). Partial recovery of myelination occurred following a 10-day washout of DCA. DCA did not affect the steady-state levels of intermediate filament proteins, but promoted the formation of anti-neurofilament antibody reactive whirls. In isolated SC cultures, DCA decreased the expression of P0 and PMP22, while it increased the levels of p75(NTR) (neurotrophin receptor), as compared with non-DCA-treated samples. DCA had modest adverse effects on neuronal and glial cell vitality, as determined by the release of lactate dehydrogenase. These results demonstrate that DCA induces a reversible inhibition of myelin-related proteins that may account, at least in part, for its clinical peripheral neuropathic effects. 相似文献
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Setton-Avruj CP Aquino JB Goedelman CJ Soto EF Villar MJ 《Neurochemical research》2002,27(11):1293-1303
In this work we analyzed variations in the expression of MBPs and P0 in ligated sciatic nerves of young and adult rats at 3, 7, and 14 days postligation (PL), by immunohistochemistry and SDS-PAGE of isolated myelin. A protein redistribution was seen in the distal stump of ligated nerves with the appearance of immunoreactive clusters. Using the KS400 image analyzer, immunostained area values were obtained from the different nerves dissected. In adult rats, there was an increase of the immunostained area for MBP from 3 to 7 days PL, coincident with a reorganization of the marker in clusters, followed by a marked decrease at 14 days. P0 immunolabeling gave similar results without, however, a decrease of the immunostained area at the longer survival time tested. Young animals showed an acceleration in the process of protein redistribution and digestion within ligated nerves, which followed a similar pattern as that of adult animals. Analysis by electrophoresis showed a marked decrease in P0 and MBP at 7 days PL in young rats and 14 days PL in adult rats. The functional significance of protein clustering within myelin in injured nerves deserves further analysis. 相似文献
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Elisa Pfeiffer Victoria Kegel Katrin Zeilinger Jan G Hengstler Andreas K Nüssler Daniel Seehofer Georg Damm 《Experimental biology and medicine (Maywood, N.J.)》2015,240(5):645-656
Primary human hepatocytes (PHH) are considered to be the gold standard for in vitro testing of xenobiotic metabolism and hepatotoxicity. However, PHH cultivation in 2D mono-cultures leads to dedifferentiation and a loss of function. It is well known that hepatic non-parenchymal cells (NPC), such as Kupffer cells (KC), liver endothelial cells (LEC), and hepatic stellate cells (HSC), play a central role in the maintenance of PHH functions. The aims of the present study were to establish a protocol for the simultaneous isolation of human PHH and NPC from the same tissue specimen and to test their suitability for in vitro co-culture. Human PHH and NPC were isolated from tissue obtained by partial liver resection by a two-step EDTA/collagenase perfusion technique. The obtained cell fractions were purified by Percoll density gradient centrifugation. KC, LEC, and HSC contained in the NPC fraction were separated using specific adherence properties and magnetic activated cell sorting (MACS®). Identified NPC revealed a yield of 1.9 × 106 KC, 2.7 × 105 LEC and 4.7 × 105 HSC per gram liver tissue, showing viabilities >90%. Characterization of these NPC showed that all populations went through an activation process, which influenced the cell fate. The activation of KC strongly depended on the tissue quality and donor anamnesis. KC became activated in culture in association with a loss of viability within 4–5 days. LEC lost specific features during culture, while HSC went through a transformation process into myofibroblasts. The testing of different culture conditions for HSC demonstrated that they can attenuate, but not prevent dedifferentiation in vitro. In conclusion, the method described allows the isolation and separation of PHH and NPC in high quality and quantity from the same donor. 相似文献
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The complexation of VO2+ ion with the high molecular mass components of the blood serum, human serum transferrin (hTf) and albumin (HSA), has been re-examined using EPR spectroscopy. In the case of transferrin, the results confirm those previously obtained, showing that VO2+ ion occupies three different binding sites, A, B1 and B2, distinguishable in the X-band anisotropic spectrum recorded in D2O. With albumin the results show that a dinuclear complex (VO)2dHSA is formed in equimolar aqueous solutions or with an excess of protein; in the presence of an excess of VO2+, the multinuclear complex (VO)xmHSA is the prevalent species, where x = 5-6 indicates the equivalents of metal ion coordinated by HSA. The structure of the dinuclear species is discussed and the donor atoms involved in the metal coordination are proposed on the basis of the measured EPR parameters. Two different binding modes of albumin can be distinguished varying the pH, with only one species being present at the physiological value. The results show that the previously named “strong” site is not the N-terminal copper binding site, and some hypothesis on the metal coordination is discussed, with the 51V Az values for the proposed donor sets obtained by DFT (density functional theory) calculations. Finally, preliminary results obtained in the ternary system VO2+/hTf/HSA are shown in order to determine the different binding strength of the two proteins. Due to the low VO2+ concentration used, the recording of the EPR spectra through the repeated acquisition of the weak signals is essential to obtain a good signal to noise ratio in these systems. 相似文献
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Background and Aims Auxin is the main phytohormone controlling root development in plants. This study uses pharmacological and genetic approaches to examine the role of auxin and nitric oxide (NO) in the activation of NADPH-dependent thioredoxin reductase (NTR), and the effect that this activity has on root growth responses in Arabidopsis thaliana.Methods Arabidopsis seedlings were treated with auxin with or without the NTR inhibitors auranofin (ANF) and 1-chloro-2, 4-dinitrobenzene (DNCB). NTR activity, lateral root (LR) formation and S-nitrosothiol content were measured in roots. Protein S-nitrosylation was analysed by the biotin switch method in wild-type arabidopsis and in the double mutant ntra ntrb.Key Results The auxin-mediated induction of NTR activity is inhibited by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO), suggesting that NO is downstream of auxin in this regulatory pathway. The NTR inhibitors ANF and DNCB prevent auxin-mediated activation of NTR and LR formation. Moreover, ANF and DNCB also inhibit auxin-induced DR5 : : GUS and BA3 : : GUS gene expression, suggesting that the auxin signalling pathway is compromised without full NTR activity. Treatment of roots with ANF and DNCB increases total nitrosothiols (SNO) content and protein S-nitrosylation, suggesting a role of the NTR-thioredoxin (Trx)-redox system in protein denitrosylation. In agreement with these results, the level of S-nitrosylated proteins is increased in the arabidopsis double mutant ntra ntrb as compared with the wild-type.Conclusions The results support for the idea that NTR is involved in protein denitrosylation during auxin-mediated root development. The fact that a high NO concentration induces NTR activity suggests that a feedback mechanism to control massive and unregulated protein S-nitrosylation could be operating in plant cells. 相似文献
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Daniele Sanna Péter Buglyó Giovanni Micera Eugenio Garribba 《Journal of biological inorganic chemistry》2010,15(6):825-839
Potentiometric (pH titrations) and spectroscopic (electron paramagnetic resonance) methods have been used to determine the
thermodynamic stability constants of the various VO2+ complexes formed after the interaction of four insulin-enhancing vanadium compounds, [VO(6-mepic)2], cis-[VO(pic)2(H2O)], [VO(acac)2], and [VO(dhp)2], where 6-mepic, pic, acac, and dhp indicate the deprotonated forms of 6-methylpicolinic acid, picolinic acid, acetylacetone,
and 1,2-dimethyl-3-hydroxy-4(1H)-pyridinone, with high molecular mass [human serum apotransferrin (hTf) and human serum albumin (HSA)] and low molecular
mass (lactate) components of blood serum. In particular, log β values for the formation of (VO)hTf (13.0 ± 0.5), (VO)2hTf (25.5 ± 0.5), (VO)HSA (9.1 ± 1.0), (VO)
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HSA (20.9 ± 1.0), cis-VO(dhp)2(hTf) (25.5 ± 0.6), cis-VO(dhp)2(HSA) (25.9 ± 0.6), (VO)hTf(lact) (14.5 ± 0.8), (VO)2hTf(lact)2 (28.5 ± 0.8), (VO)hTf(pic) (15.6 ± 0.8), and (VO)2hTf(pic)2 (30.4 ± 0.8) were determined. The values of the stability constants were used to compare the calculated composition of ternary
and quinary systems with that recently proposed by some of us through electron paramagnetic resonance and density functional
theory methods (Sanna et al. in Inorg. Chem. 49:174–187, 2010) and to predict the distribution of VO2+ ion in blood serum when one of the four insulin-enhancing vanadium compounds studied, [VO(carrier)2], is administered. 相似文献
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Rafael G. Saer Jie Pan Amelia Hardjasa Su Lin Federico Rosell A. Grant Mauk Neal W. Woodbury Michael E.P. Murphy J. Thomas Beatty 《BBA》2014
The Zn-BChl-containing reaction center (RC) produced in a bchD (magnesium chelatase) mutant of Rhodobacter sphaeroides assembles with six Zn-bacteriochlorophylls (Zn-BChls) in place of four Mg-containing bacteriochlorophylls (BChls) and two bacteriopheophytins (BPhes). This protein presents unique opportunities for studying biological electron transfer, as Zn-containing chlorins can exist in 4-, 5-, and (theoretically) 6-coordinate states within the RC. In this paper, the electron transfer perturbations attributed exclusively to coordination state effects are separated from those attributed to the presence, absence, or type of metal in the bacteriochlorin at the HA pocket of the RC. The presence of a 4-coordinate Zn2 + ion in the HA bacteriochlorin instead of BPhe results in a small decrease in the rates of the P* → P+HA− → P+QA− electron transfer, and the charge separation yield is not greatly perturbed; however coordination of the Zn2 + by a fifth ligand provided by a histidine residue results in a larger rate decrease and yield loss. We also report the first crystal structure of a Zn-BChl-containing RC, confirming that the HA Zn-BChl was either 4- or 5-coordinate in the two types of Zn-BChl-containing RCs studied here. Interestingly, a large degree of disorder, in combination with a relatively weak anomalous difference electron density was found in the HB pocket. These data, in combination with spectroscopic results, indicate partial occupancy of this binding pocket. These findings provide insights into the use of BPhe as the bacteriochlorin pigment of choice at HA in both BChl- and Zn-BChl-containing RCs found in nature. 相似文献
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Tsui-Hwa Tseng Chien-Heng Shen Wen-Shih Huang Cheng-Nan Chen Wen-Hai Liang Tseng-Hsi Lin Hsing-Chun Kuo 《Journal of biomedical science》2014,21(1):61
Background
Caffeic acid phenethyl ester (CAPE), a component of propolis, is reported to possess anti-inflammatory, anti-bacterial, anti-viral, and anti-tumor activities. Previously, our laboratory demonstrated the in vitro and in vivo bioactivity of CAPE and addressed the role of p53 and the p38 mitogen-activated protein kinase (MAPK) pathway in regulating CAPE-induced apoptosis in C6 glioma cells.Results
C6 cancer cell lines were exposed to doses of CAPE; DNA fragmentation and MAPKs and NGF/P75NTR levels were then determined. SMase activity and ceramide content measurement as well as western blotting analyses were performed to clarify molecular changes. The present study showed that CAPE activated neutral sphingomyelinase (N-SMase), which led to the ceramide-mediated activation of MAPKs, including extracellular signal-regulated kinase (ERK), Jun N-terminus kinase (JNK), and p38 MAPK. In addition, CAPE increased the expression of nerve growth factor (NGF) and p75 neurotrophin receptor (p75NTR). The addition of an N-SMase inhibitor, GW4869, established that NGF/p75NTR was the downstream target of N-SMase/ceramide. Pretreatment with MAPK inhibitors demonstrated that MEK/ERK and JNK acted upstream and downstream, respectively, of NGF/p75NTR. Additionally, CAPE-induced caspase 3 activation and poly [ADP-ribose] polymerase cleavage were reduced by pretreatment with MAPK inhibitors, a p75NTR peptide antagonist, or GW4869.Conclusions
Taken together, N-SMase activation played a pivotal role in CAPE-induced apoptosis by activation of the p38 MAPK pathway and NGF/p75NTR may explain a new role of CAPE induced apoptosis in C6 glioma. 相似文献15.
Cuiping Zhang Xiaobing Fu Peng Chen Xiaoxia Bao Fu Li Xiaoyan Sun Yonghong Lei Sa Cai Tongzhu Sun Zhiyong Sheng 《Journal of cellular and molecular medicine》2010,14(5):1135-1145
Differentiated epidermal cells can dedifferentiate into stem cells or stem cell‐like cells in vivo. In this study, we report the isolation and characterization of dedifferentiation‐derived cells. Epidermal sheets eliminated of basal stem cells were transplanted onto the skin wounds in 47 nude athymic (BALB/c‐nu/nu) mice. After 5 days, cells negative for CK10 but positive for CK19 and β1‐integrin emerged at the wound‐neighbouring side of the epidermal sheets. Furthermore, the percentages of CK19 and β1‐integrin+ cells detected by flow cytometric analysis were increased after grafting (P < 0.01) and CK10+ cells in grafted sheets decreased (P < 0.01). Then we isolated these cells on the basis of rapid adhesion to type IV collagen and found that there were 4.56% adhering cells (dedifferentiation‐derived cells) in the grafting group within 10 min. The in vitro phenotypic assays showed that the expressions of CK19, β1‐integrin, Oct4 and Nanog in dedifferentiation‐derived cells were remarkably higher than those in the control group (differentiated epidermal cells) (P < 0.01). In addition, the results of the functional investigation of dedifferentiation‐derived cells demonstrated: (1) the numbers of colonies consisting of 5–10 cells and greater than 10 cells were increased 5.9‐fold and 6.7‐fold, respectively, as compared with that in the control (P < 0.01); (2) more cells were in S phase and G2/M phase of the cell cycle (proliferation index values were 21.02% in control group, 45.08% in group of dedifferentiation); (3) the total days of culture (28 days versus 130 days), the passage number of cells (3 passages versus 20 passages) and assumptive total cell output (1 × 105 cells versus 1 × 1012 cells) were all significantly increased and (4) dedifferentiation‐derived cells, as well as epidermal stem cells, were capable of regenerating a skin equivalent, but differentiated epidermal cells could not. These results suggested that the characteristics of dedifferentiation‐derived cells cultured in vitro were similar to epidermal stem cells. This study may also offer a new approach to yield epidermal stem cells for wound repair and regeneration. 相似文献
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Jonathan D. Gary Andrew E. Wurmser Cecilia J. Bonangelino Lois S. Weisman Scott D. Emr 《The Journal of cell biology》1998,143(1):65-79
The Saccharomyces cerevisiae FAB1 gene encodes a 257-kD protein that contains a cysteine-rich RING-FYVE domain at its NH2-terminus and a kinase domain at its COOH terminus. Based on its sequence, Fab1p was initially proposed to function as a phosphatidylinositol 4-phosphate (PtdIns(4)P) 5-kinase (Yamamoto et al., 1995). Additional sequence analysis of the Fab1p kinase domain, reveals that Fab1p defines a subfamily of putative PtdInsP kinases that is distinct from the kinases that synthesize PtdIns(4,5)P2. Consistent with this, we find that unlike wild-type cells, fab1Δ, fab1tsf, and fab1 kinase domain point mutants lack detectable levels of PtdIns(3,5)P2, a phosphoinositide recently identified both in yeast and mammalian cells. PtdIns(4,5)P2 synthesis, on the other hand, is only moderately affected even in fab1Δ mutants. The presence of PtdIns(3)P in fab1 mutants, combined with previous data, indicate that PtdIns(3,5)P2 synthesis is a two step process, requiring the production of PtdIns(3)P by the Vps34p PtdIns 3-kinase and the subsequent Fab1p- dependent phosphorylation of PtdIns(3)P yielding PtdIns(3,5)P2. Although Vps34p-mediated synthesis of PtdIns(3)P is required for the proper sorting of hydrolases from the Golgi to the vacuole, the production of PtdIns(3,5)P2 by Fab1p does not directly affect Golgi to vacuole trafficking, suggesting that PtdIns(3,5)P2 has a distinct function. The major phenotypes resulting from Fab1p kinase inactivation include temperature-sensitive growth, vacuolar acidification defects, and dramatic increases in vacuolar size. Based on our studies, we hypothesize that whereas Vps34p is essential for anterograde trafficking of membrane and protein cargoes to the vacuole, Fab1p may play an important compensatory role in the recycling/turnover of membranes deposited at the vacuole. Interestingly, deletion of VAC7 also results in an enlarged vacuole morphology and has no detectable PtdIns(3,5)P2, suggesting that Vac7p functions as an upstream regulator, perhaps in a complex with Fab1p. We propose that Fab1p and Vac7p are components of a signal transduction pathway which functions to regulate the efflux or turnover of vacuolar membranes through the regulated production of PtdIns(3,5)P2. 相似文献
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Vermicomposting--An effective tool for the management of invasive weed Parthenium hysterophorus 总被引:2,自引:0,他引:2
This study reports the results of vermicomposting with Eisenia fetida of Parthenium hysterophorus mixed with cow dung in different ratios (25%, 50% and 75%) in a 18 weeks experiment. In all the treatments, a decrease in pH, OCtotal and C:N ratio, but increase in EC, Ntotal, Paval, Catotal, Ktotal and heavy metals was recorded. The cocoons production and growth rate (biomass gain worm−1 day−1) were maximum in 100% cow dung. The results indicated that parthenium can be a raw material for vermicomposting if mix with cow dung in appropriate quantity. 相似文献
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Abdol-Khalegh Bordbar Fakhrossadat Mohammadi Chris Orvig 《Journal of inorganic biochemistry》2009,103(4):643-647
Bis(maltolato)oxovanadium(IV) (BMOV), and its ethylmaltol analog, bis(ethylmaltolato)oxovanadium(IV) (BEOV), are candidate insulin-enhancing agents for the treatment of type 2 diabetes mellitus; in mid-2008, BEOV advanced to phase II clinical testing. The interactions of BMOV and its inorganic congener, vanadyl sulfate (VOSO4), with human serum apo-transferrin (hTf) were investigated using differential scanning calorimetry (DSC). Addition of BMOV or VOSO4 to apo-hTf resulted in an increase in thermal stability of both the C- and N-lobes of transferrin as a result of binding to either vanadyl compound. A series of DSC thermograms of hTf solutions containing different molar ratios of BMOV and VOSO4 were used to determine binding constants; at 25 °C the binding constants of BMOV to the C- and N-lobes of apo-hTf were found to be 3 (±1) × 105 and 1.8 (±0.7) × 105 M−1, respectively. The corresponding values for VOSO4 were 1.7 (±0.3) × 105 and 7 (±2) × 104 M−1. The results show that the vanadium species initially presented as either BMOV or VOSO4 had similar affinities for human serum transferrin due to oxidation of solvated vanadyl(IV) prior to complexation to transferrin. Binding of metavanadate () was confirmed by DSC and isothermal titration calorimetry (ITC) experiments of the interaction between sodium metavanadate (NaVO3) and hTf. 相似文献
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