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Rong Cao

Publications and source records attributed to Rong Cao.

At least 19 recordsLinked to original sources
PubMed2006

Blocking the glial function suppresses subcutaneous formalin-induced nociceptive behavior in the rat.

This study examined whether glial cells in the trigeminal nucleus caudalis (Sp5C) were necessary for orofacial nociception and nociceptive processing induced by subcutaneously (s.c.) injection of 5% formalin into left mystacial vibrissae. The immunohistochemical, immunoelectron microscopical methods and behavior assessment were used in this study. Two hours after administration of carbenoxolone (CBX, a gap junction blocker) or fluorocistrate (FCA, a glail metabolic inhibitor) into the cerebellomedullary cistern, the nociceptive behavior and scratching-cumulative time reduced significantly (P<0.01). FCA attenuated obviously the expression of Fos/NeuN-immunoreactive (-IR) neurons (mean+/-S.E.M.=29+/-2.5) and Fos/glial fibrillary acidic protein (GFAP)-IR astrocytes (7.2+/-2.2) in Sp5C. CBX decreased the number of Fos/NeuN-IR neurons (25+/-1.7), but did not affect Fos/GFAP-IR astrocytes (16.2+/-5.4), compared with vehicle-preadministered rats (Fos/NeuN-IR neurons 135+/-4.2, and Fos/GFAP-IR astrocytes 25.8+/-4). Immunoelectron microscopy established that Cx32/Cx43 heterotypic gap junctions (HGJs) were present on junction areas between astrocytes and neurons within Sp5C. The number of HGJs increased significantly following formalin s.c. injection. It suggests that the Sp5C astrocytes may play an active regulating role in orofacial nociception via Cx32/Cx43 HGJs between astrocytes and neurons of Sp5C.

Animals↗
PubMed2006

Solid-state NMR, crystallographic, and computational investigation of bisphosphonates and farnesyl diphosphate synthase-bisphosphonate complexes.

Bisphosphonates are a class of molecules in widespread use in treating bone resorption diseases and are also of interest as immunomodulators and anti-infectives. They function by inhibiting the enzyme farnesyl diphosphate synthase (FPPS), but the details of how these molecules bind are not fully understood. Here, we report the results of a solid-state (13)C, (15)N, and (31)P magic-angle sample spinning (MAS) NMR and quantum chemical investigation of several bisphosphonates, both as pure compounds and when bound to FPPS, to provide information about side-chain and phosphonate backbone protonation states when bound to the enzyme. We then used computational docking methods (with the charges assigned by NMR) to predict how several bisphosphonates bind to FPPS. Finally, we used X-ray crystallography to determine the structures of two potent bisphosphonate inhibitors, finding good agreement with the computational results, opening up the possibility of using the combination of NMR, quantum chemistry and molecular docking to facilitate the design of other, novel prenytransferase inhibitors.

Crystallography, X-Ray↗
PubMed2006

The lumbar spinal cord glial cells actively modulate subcutaneous formalin induced hyperalgesia in the rat.

We investigated the response and relationship of glial cells and neurons in lumbar spinal cord to hyperalgesia induced by the unilateral subcutaneous formalin injection into the hindpaw of rats. It was demonstrated that Fos/NeuN immunoreactive (-IR) neurons, glial fibrillary acidic protein (GFAP)-IR astrocytes and OX42-IR microglia were distributed in dorsal horn of lumbar spinal cord, predominantly in the superficial layer. In the time-course studies, GFAP-IR astrocytes were firstly detected, OX42-IR microglia were sequentially observed, Fos/NeuN-IR neurons were found slightly late. Immunoelectron microscopy studies established that many heterotypic gap junctions (HGJs), which consisting of Cx43-IR astrocytic process on one side and Cx32-IR dendrite on the other side, were present in superficial layer of dorsal horn. Ninety-one HGJs were found in 100 areas of experimental rats and occupied 91%, while only 39% HGJs were found in control rats. In experimental rats pretreated with intrathecal (i.t.) application of the carbenoxolone (a gap junction blocker) or fluorocitrate (a glial metabolic inhibitor), the paw withdrawal thermal latency was prolonged than those application of the sterile saline (i.t.). It suggests that spinal cord glial cells may play an important role for modulation of hyperalgesia induced by noxious stimuli through HGJs which located between astrocytes and neurons.

Afferent Pathways↗
PubMed2006

Differential co-expression of AMPA receptor subunits in substance P receptor-containing neurons of basal forebrain regions of C57/BL mice.

We are interested in cellular co-expression patterns of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptor subunits 1-4 (GluR1-4) in substance P receptor (SPR)-containing neurons of the basal forebrain, which may act as a morphological basis for interaction between neurokinins and glutamate-driven neuronal signaling and excitotoxicity. Immunohistochemistry and laser scanning confocal microscopy in adult C57/BL mice revealed that distribution of SPR-positive neurons overlapped with that of GluR1-4-containing ones in most basal forebrain regions, i.e. the medial septal nucleus, nucleus of diagonal band of Broca, magnocellular preoptic nucleus and substantia innominata. Neurons showing both SPR and GluR1-4-immunoreactivities were found in above cholinergic neurons-rich containing basal forebrain regions. Semi-quantification analysis indicated that about 57-95% of SPR-positive neurons displayed GluR1-4-immunoreactivity. The percentages of AMPA receptor subunits co-localizing in SPR-positive neurons were GluR4 (48%), GluR1 (47%), GluR2 (26%) and GluR3 (20%), respectively. However, the neurons co-expressing SPR and GluR1-4 were hardly detected in the basal nucleus of Meynert of the basal forebrain. The co-localization of SPR and AMPA receptors has provided a molecular basis for functional interaction between neurokinins and AMPA receptors-mediated signaling in basal forebrain neurons. This study has also implied that glutamate-driven neuronal transmission and excitotoxicity can be modulated by neurokinin peptides in most basal forebrain regions but not in the basal nucleus of Meynert, suggesting that neurokinins or SP may play certain roles in determining neuronal functional properties or excitotoxic susceptibility in the various basal forebrain regions of mammals.

Animals↗
PubMed2006

Hydroxyl-directed dinitration of carboxylate ligands mediated by lead and nickel nitrates and preparation of Pb/Ni heterometallic complexes under hydrothermal conditions.

The hydrothermal reaction of 5-hydroxyisophthalic acid (H3L) and lead and nickel nitrates produced a heterometallic polymer [Pb6Ni(mu3-OH)8(La)2]n containing heptanuclear [Pb6Ni(mu3-OH)8]6+ units and a homometallic complex {[Pb(Lb)(H2O)].(H2O)0.25}n consisting of one-dimensional lead-oxide chains: evidently, the La and Lb ligands resulted from in situ hydroxyl-directed dinitration of L ligand during the hydrothermal reaction.

Journal Article↗
PubMed2006

Enthalpy versus entropy-driven binding of bisphosphonates to farnesyl diphosphate synthase.

We report the results of an ITC (isothermal titration calorimetry) investigation of the binding of six bisphosphonates to the enzyme farnesyl diphosphate synthase (FPPS; EC 2.5.1.10) from Trypanosoma brucei. The bisphosphonates investigated were zoledronate, risedronate, ibandronate, pamidronate, 2-phenyl-1-hydroxyethane-1,1-bisphosphonate, and 1-(2,2-bisphosphonoethyl)-3-iodo pyridinium. At pH = 7.4, both risedronate and the phenylethane bisphosphonate bind in an enthalpy-driven manner (DeltaH approximately -9 to 10 kcal mol-1), but the other four bisphosphonates bind in an entropy-driven manner (DeltaS varying from 31.2 to 55.1 cal K-1 mol-1). However, at pH = 8.5, zoledronate binding switches from entropy to enthalpy-driven. The DeltaG results are highly correlated with FPPS inhibition results obtained using a radiochemical assay (R2 = 0.85, N = 11, P < 0.001). The DeltaH and DeltaS results are interpreted in terms of a model in which bisphosphonates with charged side chains have positive DeltaH values, due to the enthalpic cost of desolvation (due to strong ion-dipole interactions) and, likewise, a positive DeltaS, due to an increase in water entropy (both ligand and protein associated) on ligand binding to FPPS: the hydrophobic effect. For the neutral side chains (risedronate at pH 7.4, 8.5 and zoledronate at pH 8.5, as well as the phenylethane bisphosphonate), binding is overwhelmingly enthalpy-driven, with the enhanced activity of the basic side chain containing species being attributable to their becoming protonated in the active site. Given the large size of the bisphosphonate market and the potential importance of the development of these compounds for cancer immunotherapy and anti-parasitic chemotherapy, these results are of broad general interest in the context of the development of new, potent, and selective FPPS inhibitors.

Animals↗
PubMed2006

Two three-dimensional metal-organic frameworks containing one-dimensional hydroxyl/carboxylate mixed bridged metal chains: syntheses, crystal structures, and magnetic properties.

Two novel three-dimensional complexes formulated as [M(3)(bime)2(mu3-OH)2(HO-BDC)2]n (M = Co, 1; Cu, 2) [bime = 1,2-bis(imidazol-1'-yl)ethane, HO-H2BDC = 5-hydroxyisophthalic acid] have been hydrothermally synthesized and characterized. Both 1 and 2 exhibit similar structural frameworks resulting from one-dimensional metal/oxygen chains extended by HO-BDC, but the bridging modes of HO-BDC and coordination environments of metal centers are different. Complexes 1 and 2 crystallize in the orthorhombic system, space group Pbcn, a = 18.458(2) [18.2119(12) for 2] Angstroms, b = 12.0616(14) [11.6847(7)] Angstroms, c = 11.4859(14) [12.0688(6)] Angstroms, and Z = 4 (4). Magnetic studies show that 1 displays a slow magnetic relaxation, a large hysteresis, and distinct finite-size effects and 2 contains an antiferromagnetic chain.

Journal Article↗
PubMed2006

Cell-surface protein disulfide isomerase is required for transnitrosation of metallothionein by S-nitroso-albumin in intact rat pulmonary vascular endothelial cells.

S-nitrosation of the metal binding protein, metallothionein (MT) appears to be a critical link in affecting endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO)-induced changes in cytoplasmic and nuclear labile zinc, respectively. Although low molecular weight S-nitrosothiols also appear to affect this signaling system, less is known about the ability of extracellular protein nitrosothiols to transnitrosate MT. Accordingly, we synthesized fluorescently labeled S-nitroso-albumin (SNO-albumin, a major protein S-nitrosothiol in plasma) and determined, via confocal microscopy in fixed tissue, that it is transported into cultured rat pulmonary vascular endothelial cells in a temperature sensitive fashion. The cells were transfected with an expression vector that encodes human MT-IIa cDNA sandwiched between enhanced cyan (donor) and yellow (acceptor) fluorescent proteins (FRET-MT) that can detect conformational changes in MT through fluorescence resonance energy transfer (FRET). SNO-albumin and the membrane-permeant low molecular weight S-nitroso-l-cysteine ethyl ester (l-SNCEE) caused a conformational change in FRET-MT as ascertained by full spectral laser scanning confocal microscopy in live rat pulmonary vascular endothelial cells, a result which is consistent with transnitrosation of the reporter molecule. Transnitrosation of FRET-MT by SNO-albumin, but not l-SNCEE, was sensitive to antisense oligonucleotide-mediated inhibition of the expression of cell surface protein disulfide isomerase (csPDI). These results extend the original observations of Ramachandran et al. (Ramachandran N, Root P, Jiang XM, Hogg PJ, Mutus B. Proc Natl Acad Sci U S A 98: 9539-9544, 2001) and suggest that csPDI-mediated denitrosation helps to regulate the ability of the major plasma NO carrier (SNO-albumin) to transnitrosate endothelial cell molecular targets (e.g. MT).

Animals↗
PubMed2005

Examination of 1,5-anhydro-D-fructose and the enolone ascopyrone P, metabolites of the anhydrofructose pathway of glycogen and starch degradation, for their possible application in fruits, vegetables, and beverages as antibrowning agents.

The anhydrofructose pathway describes the degradation of glycogen and starch to 1,5-anhydro-D-fructose (1,5AnFru) and its further conversion to the enolone ascopyrone P (APP) via the transit intermediate ascopyrone M. The two products, 1,5AnFru and APP, were examined in this study for their effects in controlling the browning of selected fruits, vegetables, and beverages. The results showed that 1,5AnFru had an antibrowning effect in green tea and was able to slow turbidity development in black currant wine. APP proved to be an antibrowning agent comparable to kojic acid. It showed an antibrowning effect in a range of agricultural products, such as various cultivars of apple, pear, potato, lettuce, and varieties of green tea in an efficacy concentration range from 300 to 500 ppm. Mechanism studies indicated that, like kojic acid, APP showed inhibition toward plant polyphenol oxidase and was able to decolor quinones.

Camellia sinensis↗
PubMed2005

A chemical strategy to promote helical peptide-protein interactions involved in apoptosis.

Protein-protein interactions often involve secondary structural elements, such as helices. Protein-protein interactions within the Bcl-2 family are mediated by the helical BH3 domain of proapoptotic family members, such as Bad, Bak, Bax, or Bid. Here, we report that two 5-residue fragments located at the N- and C-termini of the 16-residue BH3 domain of Bad, respectively, serve as affinity-enhancing motifs (AEMs) for the BH3 domain. When added to the BH3 domain derived from other proapoptotic proteins such as Bak, Bax, or Bid, these AEMs significantly increased the Bcl-2-binding affinity of these BH3 peptides by promoting the helical structure. This finding may point to a new strategy for studying and mimicking helical peptide-protein interactions involved in apoptosis.

Amino Acid Motifs↗
PubMed2005

Differential co-localization of neurokinin-3 receptor and NMDA/AMPA receptor subunits in neurons of the substantia nigra of C57/BL mice.

By using a double immunofluorescence method we examined co-localization of neurokinin-3 receptor (NK-3R) and N-methyl-D-aspartate (NMDA)/alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor subunits in neurons of the substantia nigra of adult mice. Overlapping distribution of NMDA receptor subunit 1 (NR1)/AMPA receptor subunits 1-4 (GluR1-4) and NK-3R-immunoreactive neurons were found in the substantia nigra pars compacta. It revealed that all (100%) of NK-3R-positive neurons displayed NR1, GluR2 or GluR3 immunoreactivity, 80% of them showed GluR1 immunoreactivity. In contrast, these neurons exhibiting both NK-3R and GluR4 immunoreactivity were hardly detected although GluR4-positive neurons were still distributed in the substantia nigra. The co-expression of NK-3R and NMDA/AMPA receptor subunits in the nigral neurons has provided a structural basis for functional modulation of neuronal glutamate receptors by neurokinin-3, suggesting that neurokinin peptides may be involved in modulation of neuronal properties and excitotoxicity in the substantia nigra of basal ganglia.

Animals↗
PubMed2005

A new chain-like cadmium(II) coordination polymer containing chains of water molecules.

The title cadmium(II) polymer, catena-poly[[[bis(4-aminopyridine-kappaN)aquacadmium(II)]-mu-1,4-phenylenediacetato-kappa(4)O,O':O'',O'''] dihydrate], {[Cd(C10H8O4)(C5H6N2)2(H2O)].2H2O}n, comprises one-dimensional wave-like chains, in which the Cd atom is coordinated by 1,4-phenylenediacetate and 4-aminopyridine molecules. The 1,4-phenylenediacetate ligands lie about inversion centres. Extensive hydrogen-bonding interactions between the chains lead to a three-dimensional structure. Free water molecules form chains in the structure.

Journal Article↗
PubMed2004

A novel three-dimensional supramolecular coordination polymer: poly[[diaquadicadmium(II)-di-mu2-4,4'-bipyridyl-di-mu2-2-sulfonatobenzoato] dihydrate].

The hydrothermal reaction of Cd(CH3COO)2.2H2O, 4,4'-bipyridyl and 2-sulfobenzoic acid produced the title compound, {[Cd2(C7H4O5S)2(C10H8N2)2(H2O)2].2H2O}n, which forms a two-dimensional coordination polymer, the sheets of which are linked via hydrogen bonds. Two different types of Cd atoms are present, one lying on a twofold rotation axis and the other on a centre of inversion. Similarly, there are two types of bipyridyl ligand present, one lying across a twofold rotation axis and the other across a centre of inversion.

Journal Article↗
PubMed2004

trans-Diaquabis(5-carboxy-1H-imidazole-4-carboxylato-kappa2N3,O4)cobalt(II) 4,4'-bipyridine solvate.

In the title compound, [Co(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)].C(10)H(8)N(2), the Co atom is trans-coordinated by two pairs of N and O atoms from two monoanionic 4,5-dicarboxyimidazole ligands, and by two O atoms from two coordinated water molecules, in a distorted octahedral geometry. The 4,4'-bipyridine solvent molecule is not involved in coordination but is linked by an N-H...N hydrogen bond to the neutral [Co(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)] molecule. Both molecules are located on inversion centers. The crystal packing is stabilized by N-H...N and O-H...O hydrogen bonds, which produce a three-dimensional hydrogen-bonded network. Offset pi-pi stacking interactions between the pyridine rings of adjacent 4,4'-bipyridine molecules were observed, with a face-to-face distance of 3.345 (1) angstroms.

Journal Article↗
PubMed2004

[Study on the potentiation of bone marrow mesenchymal stem cells involved in sebaceous duct formation].

OBJECTIVE: To investigate the feasibility of differentiation of bone marrow mesenchymal stem cells (MSCs) into skin appandence. METHODS: Porcine MSCs were isolated from porcine marrow and grown in vitro. After labeling with BrdU, MSCs were engrafted to porcine skin. At 1, 2, 4 weeks after the transplantation, immunohistochemical examinations were carried out to detect the positive staining of BrdU and cytokeratin. RESULTS: A few sebaceous duct cells, which expressed cytokeratin, were also BrdU positive, and these cells were considered may to be transplanted MSCs-derived cells. CONCLUSION: Porcine MSCs might have the potential to differentiated into sebaceous duct cells in skin.

Animals↗
PubMed2004

A recoverable enzymatic microgel based on biomolecular recognition.

The enzyme beta-galactosidase has been immobilized through incorporation into a selectively soluble microgel, prepared from DNA, biotinylated peptide nucleic acid (PNA), and the protein avidin. The enzyme was conjugated to avidin, allowing it to be integrated directly into the microgel network. Efficient hydrolysis of a small-molecule substrate occurred at 37 degrees , but cooling and centrifuging led to precipitation of the microgels and product separation. The microgels were then reconstituted by adding fresh buffer and shaking. The enzymatic activity was completely recovered through repeated cycles. This method should be generalizable to a wide variety of other enzymes and substrates.

Avidin↗
PubMed2003

Novel silver-containing supramolecular frameworks constructed by combination of coordination bonds and supramolecular interactions.

The hydrothermal reactions of AgNO(3), 4,4'-bipy, and carboxylate ligands gave rise to three supramolecular architectures, namely [Ag(bipy)].H(2)SIPA.1/2bipy.H(2)O (1), [Ag(bipy)].1/2H(2)btec.H(2)O (2), and [Ag(bipy)](2).H(2)dpstc.2H(2)O (3) (H(3)SIPA = 5-sulfoisophthalic acid, bipy = 4,4'-bipyridine, H(4)btec = 1,2,4,5-benzenetetracarboxylic acid, H(4)dpstc = 3,3',4,4'-tetracarboxydiphenyl sulfone). All complexes are extended from Ag-bipy linear chains by the combination of coordination bonds and supramolecular interactions in two different approaches. Complexes 1 and 3 comprise two-dimensional frameworks. In the two complexes, a one-dimensional ladderlike structure is first formed by the connection of a Ag-bipy chain through hydrogen bonding between a free carboxylate/bipy ligand and weak coordinative interactions between a free carboxylate ligand and silver ion. The ladderlike structure is then extended to a two-dimensional layer architecture by pi...pi interactions between bipy ligands of the Ag-bipy chains. Complex 2 possesses a three-dimensional framework. The free H(2)btec(2)(-) ligands form a two-dimensional layer network by hydrogen-bonding interactions between protonated and deprotonated carboxylate groups; meanwhile, pi.pi interactions between bipy ligands of Ag-bipy chains also result in a two-dimensional layer. The two layers are further connected by weak Ag-O interactions to generate a three-dimensional supramolecular structure.

Journal Article↗