Biomedical subjects

Yong Peng

Publications and source records attributed to Yong Peng.

At least 19 recordsLinked to original sources

PubMed2006

Suppressor role of rat CD8+CD45RClow T cells in experimental autoimmune uveitis (EAU).

To determine whether decreased regulatory T cell activity contributes to the pathogenesis of recurrent experimental autoimmune uveitis (EAU), we compared the immunoregulatory activity of CD8+CD45RClow T cells isolated from rats that had recovered from acute EAU with those from rats with the progressive, recurrent disease. Our results showed that CD8+CD45RClow T cells isolated from the recovered rats showed suppressive activity in vitro, whereas those from rats with progressive, recurrent EAU do not. Depletion of CD8+CD45RClow T cells from T cells used for adoptive transfer of EAU increased the pathogenic activity of the T cells. Co-transfer of CD8+CD45RClow T cells with uveitogenic T cells prevented the relapse of disease in the recipient rats. The suppressive CD8+CD45RClow T cells expressed increased levels of Foxp3 after stimulation in vitro with the autoantigen, and inhibited the production of IFN-gamma by autoreactive T cells. Our data indicate that the decreased suppressive activity of CD8+CD45RClow T cells is correlated with disease development in this autoimmune disease. Further studies on the biology of this T cell population should provide much needed insights into disease pathogenesis.

Adoptive Transfer↗

PubMed2006

Polysome-bound endonuclease PMR1 is targeted to stress granules via stress-specific binding to TIA-1.

The generalized process of mRNA decay involves deadenylation followed by release from translating polysomes, decapping, and exonuclease decay of the mRNA body. In contrast the mRNA endonuclease PMR1 forms a selective complex with its translating substrate mRNA, where it initiates decay by cleaving within the mRNA body. In stressed cells the phosphorylation of the alpha subunit of eukaryotic initiation factor 2 causes translating mRNAs to accumulate with stalled 48S subunits in large subcellular structures termed stress granules (SGs), wherein mRNAs undergo sorting for reinitiation, storage, or decay. Given the unique relationship between translation and PMR1-mediated mRNA decay, we examined the impact of stress-induced dissociation of polysomes on this process. Arsenite stress disrupts the polysome binding of PMR1 and its substrate mRNA but has no impact on the critical tyrosine phosphorylation of PMR1, its association with substrate mRNA, or its association with the functional approximately 680-kDa mRNP complex in which it normally resides on polysomes. We show that arsenite stress drives PMR1 into an RNase-resistant complex with TIA-1, and we identify a distinct domain in the N terminus of PMR1 that facilitates its interaction with TIA-1. Finally, we show that arsenite promotes the delayed association of PMR1 with SGs under conditions which cause tristetraprolin and butyrate response factor 1, proteins that facilitate exonucleolytic mRNA, to exit SGs.

Animals↗

PubMed2006

Identification and characterization of selenoprotein K: an antioxidant in cardiomyocytes.

Selenoprotein K (SelK) is a newly identified selenoprotein. We showed that selenium incorporation into SelK was dependent on the 3'UTR of SelK mRNA. Sec insertion sequence (SECIS) RNA binding assays demonstrated that human SBP2 bound to the SelK SECIS element through the conserved non-Watson-Crick base pair quartet but not the AAT motif. Examination of the expression pattern revealed that human SelK mRNA was highly expressed in heart. Immunofluorescence analysis showed that SelK localized to the endoplasmic reticulum. Using SelK recombinant adenovirus, we found that overexpression of SelK attenuated the intracellular reactive oxygen species level and protected cells from oxidative stress-induced toxicity in cardiomyocytes. Our findings indicated that SelK is a novel antioxidant in cardiomyocytes and is related to the regulation of cellular redox balance.

3' Untranslated Regions↗

PubMed2006

Expression of T-STAR gene is associated with regulation of telomerase activity in human colon cancer cell line HCT-116.

AIM: To investigate the effects on telomerase activity of transfection of human T-STAR gene full-length sense cDNA or partial antisense cDNA into human colon cancer cell line HCT-116. METHODS: mRNA and protein expression levels of T-STAR gene were determined by RT-PCR and western blot, and telomerase activity was measured by PCR-ELISA, after transfection of T-STAR sense or antisense gene into HCT-116 cells with lipofectamine. RESULTS: T-STAR gene expression was enhanced or knocked down both at mRNA and protein levels, and telomerase activity was significantly increased or decreased. CONCLUSION: The T-STAR gene may participate in regulation of telomerase activity in human colon cancer HCT-116 cells in a parallel fashion.

DNA, Antisense↗

PubMed2006

In vitro activation of CD8 interphotoreceptor retinoid-binding protein-specific T cells requires not only antigenic stimulation but also exogenous growth factors.

In a previous study, we demonstrated that immunization with the uveitogenic peptide interphotoreceptor retinoid-binding protein (IRBP) 1-20 induces both CD4 and CD8 uveitogenic T cells in the B6 mouse. In the current study, we determined the role of the CD8 IRBP-specific T cells in the pathogenesis of experimental autoimmune uveitis. We also determined the conditions that facilitated the activation of CD8 autoreactive T cells. Our results showed that the beta2-microglobulin(-/-) mouse had a greatly decreased susceptibility to induction of experimental autoimmune uveitis by adoptive transfer of IRBP-specific T cells from B6 mice. We also showed that unlike CD4 autoreactive T cells, activated CD8 autoreactive T cells produced only a limited number and amounts of growth factors. As a result, in the absence of exogenously supplied growth factor(s), CD8 T cell activation and expansion were aborted. However, the growth and expansion of triggered CD8 autoreactive T cells could be supported by various cytokines. In addition to factors produced by activated CD4 autoreactive T cells, factors produced by nonlymphoid cells, such as IL-7 and IL-15, and unidentified factors in the culture supernatants of astrocytes and retinal pigment epithelial cells support the CD8 autoreactive T cells as well. Finally, we showed that, although several cytokines augmented the CD8 T cell response in vitro, different cytokines appeared to act on different CD8 subsets or on different activation/differentiation phases of CD8 autoreactive T cells. As a result, cytokines, such as IL-7, supported the proliferation and survival of CD8 IRBP-specific T cells, while others had only a growth-promoting effect.

Adoptive Transfer↗

PubMed2006

[The mechanism and treatment phases chosen of glycine for inhibition lipopolysaccharide induced Kupffer cells activation].

OBJECTIVE: To explore the possible mechanism and optimal treatment phase of glycine for inhibition lipopolysaccharide (LPS) induced Kupffer cells (KCs) activation. METHODS: The KCs were isolated from 40 BALB/c mice and divided into four groups: the endotoxin group, the prevention group, the early treatment group and the later treatment group (n = 10). The endotoxin group was treated with 10 mg/L LPS, and in the other three groups, glycine (1 mmol/L) was given 24 h before, or at 0 h or 4 h respectively after LPS stimulation. At 0 h, 1 h, 2 h, 6 h and 12 h after LPS stimulation, the mRNA levels and protein expression of interleukin-1 receptor associated kinase-4 (IRAK-4) were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot respectively, and nuclear factor-kappaB (NF-kappaB) activities as well as tumor necrosis factor alpha (TNF-alpha) levels were also detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: The climax values of IRAK-4, NF-kappaB and TNF-alpha were significantly higher in the endotoxin group and the later treatment group than that in the other two groups (t = 3.17, 4.33, 2.47, 126.73, P < 0.01). CONCLUSION: The results indicated that prophylactic or simultaneous treatment with glycine could effectively inhibit LPS-induced KCs activation by inhibiting IRAK-4 expression.

Animals↗

PubMed2006

Distinguishing the medicinal herb Oldenlandia diffusa from similar species of the same genus using fluorescence microscopy.

The light microscope is routinely used for microscopic identification of Chinese Materia Medica (CMM). However, the fluorescence microscope has not been used for this purpose until now. The CMM, Baihuasheshecao, mostly used as a component of herb tea, is a well known folk-medicine in China. According to the Chinese Pharmacopoeia, its source is the species Oldenlandia diffusa (Willd.) Roxb. Two other species of the same genus, namely O. corymbosa (L.) Lam and O. tenelliflora Bl., had been found in use as Baihuasheshecao. To find a quick and easy method to distinguish O. diffusa from these similar species of the same genus, the fluorescence microscope was used to investigate the fluorescence emission characteristics of the three tissues, which were compared with light microscopy images of the same material. The results showed that some tissues of the three herbs emit autofluorescence. Specially, the wall of endoderm cells of O. diffusa and O. tenelliflora emit autofluorescence, while similar tissue of O. corymbosa does not. Hence, fluorescence microscopy can be helpful in the identification of CMM.

Microscopy, Fluorescence↗

PubMed2006

Application of microscopic techniques in authentication of herbal tea--Ku-Ding-Cha.

Ku-Ding-Cha, a kind of herbal tea, has been widely used in China for a long time to support cardiovascular health. Confusion arises because in different parts of China different plants are used to produce the commercial teas. It is important to determine the identity of the used species in order to authenticate genuine Ku-Ding-Cha. However, once the plants have been processed, it is difficult to identify them through macroscopic identification; other means are necessary. A comparative study was made on 24 samples of Ku-Ding-Cha, including five standard identified and authenticated plants and 19 commercial samples, by microscopic techniques. The results showed that the shapes of leaf blades, xylem cells, stone cells, and calcium oxalate crystals could be used for the identification of the plants from which the commercial products were made. The method was proven to be quick, handy, simple, and convenient.

Beverages↗

PubMed2006

Construction of a microsatellite linkage map with two sequenced rice varieties.

Based on the successful development of new microsatellite markers from the data of two whole-sequenced rice varieties, japonica variety Nipponbare and indica variety 9311, an F2 population of 90 lines, which was derived from a single cross between Nipponbare and 9311, was applied to construct a genetic linkage framework map. The map covered 2 455.7 cM of total genomic length, and consisted of 152 simple sequence repeats (SSRs) loci including 46 pairs of new SSR primers developed by our research institute. The average genetic distance between two markers was 16.16 cM. In addition, markers RM345 and RM494, which have not been mapped on the Temnykh's map et al. (2001) were anchored on the sixth chromosome of this map. We compared this research with maps of Temnykh et al.(2001) and LAN et al. (2003) regarding the aspects of type and size of population, type and quantity of markers, and the marker arrangement order on chromosome, etc. Results indicated that the similarity of marker linear alignment was 93.81% between this map and T-map. Finally, the important significance of using sequenced rice varieties to construct linkage map was also discussed.

Chromosome Mapping↗

PubMed2006

Analysis of segregation distortion of molecular markers in F2 population of rice.

A genetic linkage map comprising 148 SSR markers loci was constructed using an F2 population consisting of 90 lines derived from a sub-specific cross between a japonica variety Nipponbare and an indica variety Guangluai-4. The F2 population showed high significantly distorted segregations. Among these SSR markers, 49 markers(33.11%) showed the genetics distortion(P<0.05). Of them, 36 markers deviated toward male parent indica GuangLuAi-4 and 13 markers toward heterozygote, but none toward the female parent Nipponbare. It was found that the segregation distortion might be caused by gametophyte and zygote. Since most gametophyte loci and sterility loci were mapped in segregation distortion regions, it indicated that the segregation distortion may be caused by these gametophyte loci and sterility loci. Finally, this research also analyzed the skewed segregation of some markers, which had not been mapped on chromosome.

Biomarkers↗

PubMed2006

[The influence with block the endotoxin signal transduction for ischemia/reperfusion injury of graft liver in rats].

OBJECTIVE: To explore the feasibility of interleukin 1 receptor associated kinase-4 (IRAK-4) as gene therapy target for liver ischemia/reperfusion injury (I/RI) and effective approach in vivo for short hairpin RNA (shRNA) interference used to gene therapy in liver graft hqappened. METHODS: Sprague-Dawley rats were randomly divided into three groups: the control group, the in vivo transfection group (IVT) and the cold ischemia transfection group (CIT). Experiments of orthotopic liver transplantation were performed by two-cuff method. CIT were perfused with IRAK-4-shRNA plasmid (pSIIRAK-4) during cold ischemia phase, IVT received the equivalent volumes (2 mL) of pSIIRAK-4 after portal vein inosculated, and the control group leaved without any treatment. At 0 min, 60 min and 180 min after reperfusion, the expression of IRAK-4 gene and protein level were determined by RT-PCR and Western blot. The serum TNF-alpha level was detected by ELISA. Liver histopathological changes and cell apoptosis were observed by electron microscope and TUNEL. RESULTS: After reperfusion, the expression of IRAK-4 were largely depressed in CIT than that of IVT and the control group (P < 0.01), and furthermore, the serum TNF-alpha level, proportion of hepatocyte apoptosis and severity of hepatocyte injury were also lower than the latter. CONCLUSION: These results indicate that depression IRAK-4 expression with IRAK-4-shRNA through portal vein perfusion during cold ischemia phase could effectively blunt graft hepatic I/RI.

Animals↗

PubMed2006

[Pharmaphylogenetic study on isopyroideae (Ranunculaceae)].

OBJECTIVE: To study the pharmaphylogenetic of medicinal plants of Isopyroideae (Ranunculaceae). METHOD: Comprehensively analyze the correlation between phylogeny, chemical constituents and pharmaceutical aspects of Isopyroideae plants, based on chemical, pharmaceutical (both ethnopharmacologic and pharmacological) information, linking with different plant systems of Ranunculaceae. RESULT: Plants from Aquilegia mainly contain flavonoids constituents while the major chemical constituents of Isopyrum are bisbenzylisoquinoline alkaloids. Chemical characteristics also support that this taxon should be separated from Thalictrodeae, and constituted an independent subfamily, namely, Isopyroideae.

Anti-Infective Agents↗

PubMed2006

[Preliminary pharmaphylogenetic study on Ranunculaceae].

OBJECTIVE: To deal with the correlation between phylogeny, chemical constituents and pharmaceutical aspects of Ranunculaceae, namely a pharmaphylogenic study of this taxon. METHOD: Based on chemical, pharmaceutical (both ethnopharmacologic and pharmacological) information, linking with different plant systems of Ranunculaceae. RESULT: Chemical constituents of this taxon included several natural groups: benzylisoquinoline alkaloid, ranunculin, triterpenoid glycoside and diterpene alkaloid etc. Ranunculin and magoflorine were found to present simultaneously in some plants of this taxon. CONCLUSION: Combining with therapeutic information, pharmaphylogenic research were in accordance with the phylogenetic system presented by Tamura that Ranunculaceae was proposed to be divided into six sub-families: Helleboroideae, Ranunculoideae, Cimicfugoideae, Isopyroideae, Thalictroideae and Coptidoideae. Results also supported the establishment of Cimicifugoideae.

Benzylisoquinolines↗

PubMed2005

Microbial fibrinolytic enzymes: an overview of source, production, properties, and thrombolytic activity in vivo.

Accumulation of fibrin in the blood vessels usually results in thrombosis, leading to myocardial infarction and other cardiovascular diseases. For thrombolytic therapy, microbial fibrinolytic enzymes have now attracted much more attention than typical thrombolytic agents because of the expensive prices and the undesirable side effects of the latter. The fibrinolytic enzymes were successively discovered from different microorganisms, the most important among which is the genus Bacillus from traditional fermented foods. The physiochemical properties of these enzymes have been characterized, and their effectiveness in thrombolysis in vivo has been further identified. Therefore, microbial fibrinolytic enzymes, especially those from food-grade microorganisms, have the potential to be developed as functional food additives and drugs to prevent or cure thrombosis and other related diseases.

Animals↗

PubMed2005

Characterization and crystallization of human DPY-30-like protein, an essential component of dosage compensation complex.

Human DPY-30-like is a homolog of C. elegans DPY-30. DPY-30 is an essential component of dosage compensation machinery and loss of dpy-30 activity results in XX-specific lethality. In XO animals, DPY-30 is required for developmental processes other than dosage compensation. In yeast, the homolog of DPY-30, Saf19p, functions as a member of histone 3 lysine 4 methylation complex, which is the key part of epigenetic developmental control. In this report, human DPY-30-like protein was overexpressed and purified with the goal of structure determination. It was crystallized at 291 K in hanging drops by the vapour diffusion technique from a precipitant solution consisting of (NH4)2SO4 (1.5-2.0 M), Tris-HCl (0.1 M, pH 8.0). The crystal diffracted to 2.7 A resolution at 100 K in-house and belongs to the space group P4(1)2(1)2 or P4(3)2(1)2 with unit-cell parameters of a=b=74.5 A, c=87.0 A, alpha=beta=gamma=90.0 degrees. The asymmetric unit contains two molecules with 49% solvent content. We also analyzed its biochemical and biophysical characterizations. Efforts are now under way to determine the molecular structure of the DPY-30-like. These studies will open a new avenue towards the structure-based functional analysis of human DPY-30-like and dosage compensation machinery.

Animals↗

PubMed2005

Accurate determination of pyridine-poly(amidoamine) dendrimer absolute binding constants with the OPLS-AA force field and direct integration of radial distribution functions.

OPLS-AA force field and direct integration of intermolecular radial distribution functions (RDF) were employed to calculate absolute binding constants of pyridine molecules to amino group (NH2) and amide group hydrogen atoms in and first generation poly(amidoamine) dendrimers in chloroform. The average errors in the absolute and relative association constants, as predicted with the calculations, are 14.1% and 10.8%, respectively, which translate into ca. 0.08 and 0.06 kcal/mol errors in the absolute and relative binding free energies. We believe that this level of accuracy proves the applicability of the OPLS-AA, force field, in combination with the direct RDF integration, to reproducing and predicting absolute intermolecular association constants of low magnitudes (ca. 0.2-2.0 range).

Journal Article↗

PubMed2005

A shared epitope of the interphotoreceptor retinoid-binding protein recognized by the CD4+ and CD8+ autoreactive T cells.

We previously demonstrated that cultures of rat uveitogenic T cells rapidly become dominated by CD4+ cells, but activation of CD8+ autoreactive T cells also occurred during the in vitro culture of in vivo-primed T cells. In the present study, we show that the commonly used uveitogenic peptide, interphotoreceptor retinoid-binding protein (IRBP) 1-20, generated both CD4+ and CD8+ autoreactive T cells in the C57BL/6 (B6) mouse and that this 20-mer contains at least two distinct antigenic epitopes. To determine whether the CD8 response was Ag-specific and whether CD4+ and CD8+ IRBP1-20-specific T cells recognize distinct antigenic epitopes, we prepared highly purified CD4+ and CD8+ T cells from IRBP1-20-primed mice and tested their proliferative response to a large panel of truncated peptides derived from IRBP1-20. The results showed that both CD4+ and CD8+ T cells recognized the same spectrum of peptides. In addition, peptides P10-18 were found to bind effectively to CD8+ IRBP1-20-specific T cells when complexed with recombinant H-2K(b) and also stimulate the proliferation and cytokine production of CD4+ IRBP1-20-specific T cells. Our results document for the first time that CD8+ and CD4+ autoreactive T cells display characteristic epitope recognition and they both recognize the same core epitope.

Amino Acid Sequence↗

PubMed2005

[Expression of CD14 and Toll-like receptor 4 on Kupffer cells and its role in ischemia-reperfusion injury on rat liver graft].

OBJECTIVE: To study the expression of lipopolysaccharide (LPS) receptor CD14 and Toll-like receptor 4 (TLR4) on Kupffer cells and its role in ischemia-reperfusion injury (IRI) on rat liver graft. METHODS: The Kupffer cells following IRI were isolated and divided into control, ischemia-reperfusion (IR), and anti-CD14 antibody group. The mRNA and protein expression of CD14 and TLR4, nuclear factor kappa B (NF-kappaB) activity and TNF-alpha level in supernatant were measured. RESULTS: The mRNA and protein expression of CD14 and TLR4 in IR group were significantly higher than those in control group (P < 0.01). The NF-kappaB activity and TNF-alpha level in IR group were significantly higher than those in control group (P < 0.01), and they greatly decreased after anti CD14 antibody treatment (compared with IR group, P < 0.05), but were still significantly higher than those in control group (P < 0.01). CONCLUSIONS: LPS following IRI could up-regulate CD14 and TLR4 gene and protein expression on Kupffer cells, and subsequently activate NF-kappaB to produce cytokines, but other signal transduction pathways might also participate in the IRI.

Animals↗