Biomedical subjects

Yuan Yang

Publications and source records attributed to Yuan Yang.

At least 19 recordsLinked to original sources

PubMed2024

A base editor for the long-term restoration of auditory function in mice with recessive profound deafness.

A prevalent recessive mutation (c.2485C>T, p.Q829X) within the OTOF gene leads to profound prelingual hearing loss. Here we show that in Otof mice harbouring a mutation (c.2482C>T, p.Q828X) homozygous to human OTOF that faithfully mimics the hearing-loss phenotype, a base editor (consisting of the deaminase ABE7.10max and the Cas9 variant SpCas9-NG) packaged in adeno-associated viruses and injected into the inner ear of the mice via the round-window membrane effectively corrected the pathogenic mutation, with no apparent off-target effects. The treatment restored the levels of the otoferlin protein in 88% of the inner hair cells and stably rescued the auditory function of the mice to near-wild-type levels for over 1.5 years while improving synaptic exocytosis in the inner hair cells. We also show that an adenine base editor that targets the prevalent human OTOF mutation restored hearing in humanized mice to levels comparable to those of the wild-type counterparts. Base editors may be effective for the treatment of hereditary deafness.

Animals↗

PubMed2007

Breaches of the pial basement membrane and disappearance of the glia limitans during development underlie the cortical lamination defect in the mouse model of muscle-eye-brain disease.

Neuronal overmigration is the underlying cellular mechanism of cerebral cortical malformations in syndromes of congenital muscular dystrophies caused by defects in O-mannosyl glycosylation. Overmigration involves multiple developmental abnormalities in the brain surface basement membrane, Cajal-Retzius cells, and radial glia. We tested the hypothesis that breaches in basement membrane and the underlying glia limitans are the key initial events of the cellular pathomechanisms by carrying out a detailed developmental study with a mouse model of muscle-eye-brain disease, mice deficient in O-mannose beta31,2-N-acetylglucosaminyltransferase 1 (POMGnT1). The pial basement membrane was normal in the knockout mouse at E11.5. It was breached during rapid cerebral cortical expansion at E13.5. Radial glial endfeet, which comprise glia limitans, grew out of the neural boundary. Neurons moved out of the neural boundary through these breaches. The overgrown radial glia and emigrated neurons disrupted the overlying pia mater. The overmigrated neurons did not participate in cortical plate (CP) development; rather they formed a diffuse cell zone (DCZ) outside the original cortical boundary. Together, the DCZ and the CP formed the knockout cerebral cortex, with disappearance of the basement membrane and the glia limitans. These results suggest that disappearance of the basement membrane and the glia limitans at the cerebral cortical surface during development underlies cortical lamination defects in congenital muscular dystrophies and a cellular mechanism of cortical malformation distinct from that of the reeler mouse, double cortex syndrome, and periventricular heterotopia.

Animals↗

PubMed2007

Synthesis and characterization of biocompatible Fe3O4 nanoparticles.

In this study, magnetite (Fe3O4) nanoparticles with a size range of 8-20 nm were prepared by the modified controlled chemical coprecipitation method from the solution of ferrous/ferric mixed salt-solution in alkaline medium. In the process, two kinds of surfactant (sodium oleate and polyethylene glycol) were studied; then, sodium oleate was chosen as the apt surfactant to attain ultrafine, nearly spherical and well-dispersed (water-base) Fe3O4 nanoparticles, which had well magnetic properties. The size and size distribution of nanoparticles were determined by particle size analyzer. And the magnetite nanoparticles was characterized by X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), electron diffraction (ED) photography, Fourier transform infrared spectrometer (FT-IR), and vibrating-sample magnetometer (VSM). Also the effect of many parameters on the Fe3O4 nanoparticles was studied, such as reaction temperature, pH of the solution, stirring rate and concentration of sodium oleate. And the 5-dimethylthiazol-2-yl-2,5- diphenyltetrazolium bromide (MTT) assay was performed to evaluate the biocompatibility of magnetite nanoparticles. The results showed that the Fe3O4 nanoparticles coated by sodium oleate had a better biocompatibility, better magnetic properties, easier washing, lower cost, and better dispersion than the magnetite nanoparticles coated by PEG.

3T3 Cells↗

PubMed2006

Regulation of IL-1 and TNF receptor expression and function by endogenous macrophage migration inhibitory factor.

Macrophage migration inhibitory factor (MIF) has a key role in regulation of innate and adaptive immunity and is implicated in sepsis, tumorigenesis, and autoimmune disease. MIF deficiency or immunoneutralization leads to protection against fatal endotoxic, exotoxic, and infective shock, and anti-inflammatory effects in other experimental models of inflammatory disease. We report a novel regulatory role of MIF in type 1 IL-1R and p55 TNFR expression and function. Compared with wild-type cells, MIF-deficient cells were hyporesponsive to IL-1- and TNF-induced MAPK activity, AP-1 activity, and cellular proliferation, while NF-kappaB function was preserved. Hyporesponsiveness of MIF-deficient cells was associated with down-regulation of cytokine receptor expression, which was restored by reconstitution of either an upstream kinase of MAPK, MAPK/ERK kinase, or MIF. These data suggest that endogenous MIF is required for cytokine activation of MAPK/AP-1 and cytokine receptor expression. This autocrine regulatory pathway defines an important amplifying role of endogenous MIF in cytokine-mediated immune and inflammatory diseases and provides further molecular evidence for the critical role of MIF in cellular activation.

Animals↗

PubMed2006

Not polymorphism but methylation of class II transactivator gene promoter IV associated with persistent HBV infection.

BACKGROUND: Class II transactivator (CIITA) is the major rate-limiting regulator for expression of class II major histocompability complex (MHC-II). Human CIITA gene expression is controlled by four distinct promoters (pIto pIV). OBJECTIVE: To evaluate the relationship among polymorphism and methylation status of CIITA gene promoters and persistent hepatitis B virus (HBV) infection. METHODS: We recruited 21 patients with hepatocellular carcinoma (HCC), 45 liver cirrhosis (LC), 65 chronic hepatitis B (CHB), 26 acute hepatitis B (AHB) and 95 healthy blood donors. Polymorphism of CIITA gene promoters was assayed by PCR-SSCP-sequencing. Bioinformatics analysis was employed to predict the existence of CpG islands. Methylation-specific PCR (MSP) was used to detect the methylation status of CIITA gene pIV. RESULTS: No sequence differences were observed at CIITA genes pI, III and IV among HCC, LC, CHB, AHB patients and healthy controls. No CpG islands were found in the pI, pII and pIII sequences, but there was a CpG island in pIV. The frequency of methylated POV was not significantly different within persistent HBV infection groups (patients with HCC, LC or CHB). Significance was found between the persistent infection group and acute HBV infection or healthy controls. CONCLUSIONS: CIITA gene promoter sequences are conserved. PIV is highly methylated and associated with host susceptibility to HBV persistent infection.

DNA Methylation↗

PubMed2006

Single nucleotide polymorphism C677T in the methylenetetrahydrofolate reductase gene might be a genetic risk factor for infertility for Chinese men with azoospermia or severe oligozoospermia.

AIM: To analyze the distribution of the single nucleotide polymorphism (SNP) C677T in the methylenetetrahydrofolate reductase (MTHFR) gene in 355 infertile Chinese patients with idiopathic azoospermia or severe oligozoospermia and 252 fertile Chinese men as controls to explore the possible association of the SNP and male infertility. METHODS: Using the polymerase chain reaction (PCR)-restriction fragment length polymorphism technique, the allele and genotype distribution of SNP C677T in the MTHFR gene were investigated in both patients and controls. RESULTS: The frequencies of allele T (40.9% vs 30.4%, P = 0.002, odds ration [OR] = 1.58, 95% confidence interval [CI]: 1.24-2.02) and mutant homozygote (TT) (18.3% vs. 11.5%, P=0.023, OR=1.72, 95% CI: 1.07-2.76) as well as carrier with allele (TT + CT) (63.4% vs. 49.2%, P = 0.0005, OR = 1.79, 95% CI: 1.29-2.48) in infertile patients were significantly higher than those in controls. After patient stratification, the significant differences in distribution of the SNP between each patient subgroup and control group still remained. CONCLUSION: Our findings indicate that there is an association of SNP C677T in the MTHFR gene with male infertility, suggesting that this polymorphism might be a genetic risk factor for male infertility in Chinese men.

Adult↗

PubMed2006

Loss of N-linked glycosylation reduces urea transporter UT-A1 response to vasopressin.

The vasopressin-regulated urea transporter (UT)-A1 is a transmembrane protein with two glycosylated forms of 97 and 117 kDa; both are derived from a single 88-kDa core protein. However, the precise molecular sites and the function for UT-A1 N-glycosylation are not known. In this study, we compared Madin-Darby canine kidney cells stably expressing wild-type (WT) UT-A1 to Madin-Darby canine kidney cell lines stably expressing mutant UT-A1 lacking one (A1m1, A1m2) or both glycosylation sites (m1m2). Site-directed mutagenesis revealed that UT-A1 has two glycosylation sites at Asn-279 and -742. Urea flux is stimulated by 10 nM vasopressin (AVP) or 10 microM forskolin (FSK) in WT cells. In contrast, m1m2 cells have a delayed and significantly reduced maximal urea flux. A 15-min treatment with AVP and FSK significantly increased UT-A1 cell surface expression in WT but not in m1m2 cells, as measured by biotinylation. We confirmed this finding using immunostaining. Membrane fractionation of the plasma membrane, Golgi, and endoplasmic reticulum revealed that AVP or FSK treatment increases UT-A1 abundance in both Golgi and plasma membrane compartments in WT but not in m1m2 cells. Pulse-chase experiments showed that UT-A1 half-life is reduced in m1m2 cells compared with WT cells. Our results suggest that mutation of the N-linked glycosylation sites reduces urea flux by reducing UT-A1 half-life and decreasing its accumulation in the apical plasma membrane. In vivo, inner medullary collecting duct cells may regulate urea uptake by altering UT-A1 glycosylation in response to AVP stimulation.

Animals↗

PubMed2006

Novel injectable calcium phosphate/chitosan composites for bone substitute materials.

In this study, a novel injectable bone substitute material was developed which consists of chitosan, citric acid and glucose solution as the liquid phase, and tricalcium phosphate powder as the solid phase. This material was moldable because of its paste consistency after mixing. We used four groups of cement to investigate the mechanical properties and biocompatibility of the new biomaterial in vitro, which were named group A (10% citric acid), B (15% citric acid), C (20% citric acid) and D (25% citric acid). The setting times of the cements were 5-30 min. X-ray diffraction analysis showed that the products were hydroxyapatite (HA) and dicalcium phosphate anhydrous. When the concentration of citric acid was increased, the compressive strength of specimen increased. Through the simulated body fluid test, we observed the material was bioactive. Group D could induce Ca and P ions to deposit the surface group D quickly. These results indicated that the concentration of citric acid in the liquid component affected the mechanical properties and bioactivity of cements. The cell cultivation test showed that the cytocompatibility of the new biomaterial was good. The method for preparing the novel bone substitute material is simple. The starting material is more readily available and cheaper than HA, poly(methyl methacrylate), and so on. The cement could have good prospects for medical application.

Animals↗

PubMed2006

A genetic model for muscle-eye-brain disease in mice lacking protein O-mannose 1,2-N-acetylglucosaminyltransferase (POMGnT1).

Protein O-mannose beta1,2-N-acetyglucosaminyltransferase 1 (POMGnT1) is an enzyme involved in the synthesis of O-mannosyl glycans. Mutations of POMGnT1 in humans result in the muscle-eye-brain (MEB) disease. In this study, we have characterized a null mutation generated by gene trapping with a retroviral vector inserted into the second exon of the mouse POMGnT1 locus. Expression of POMGnT1 mRNA was abolished in mutant mice. Glycosylation of alpha-dystroglycan was also reduced. POMGnT1 mutant mice were viable with multiple developmental defects in muscle, eye, and brain, similar to the phenotypes observed in human MEB disease. The present study provides the first genetic animal model to further dissect the roles of POMGnT1 in MEB disease.

Animals↗

PubMed2006

Endogenous macrophage migration inhibitory factor modulates glucocorticoid sensitivity in macrophages via effects on MAP kinase phosphatase-1 and p38 MAP kinase.

The pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) is induced by glucocorticoids (GCs), but it was not previously known if MIF regulates cellular sensitivity to GC. Here we show in GC and LPS-treated peritoneal macrophages derived from MIF-/- and wt mice that the absence of endogenous MIF is associated with increased sensitivity to GC of TNF release. This is associated with increased expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), concomitant decreased phosphorylation of p38 MAPK, but no effect of MIF on nuclear factor kappaB (NF-kappaB). These results demonstrate that MIF regulates GC sensitivity by phosphorylation of p38, and provides a cellular mechanism for this observation, indicating that MKP-1 is a central target of this regulation.

Animals↗

PubMed2006

Preliminary study of the relationship between DAZ gene copy deletions and spermatogenic impairment in Chinese men.

Copy deletion screening of DAZ gene family on the Y chromosome in 485 patients with idiopathic azoospermia or oligozoospermia and 236 fertile men revealed that the prevalence of deletion patterns of the entire DAZ gene and DAZ1/DAZ2 gene were significantly higher in the patients than in fertile men. The deletion patterns correlate with spermatogenic impairment in a Chinese population.

Adult↗

PubMed2006

Chromosomal abnormality and Y chromosome microdeletion in Chinese patients with azoospermia or severe oligozoospermia.

Chromosomal abnormality and Y chromosome microdeletion are regarded as two frequent genetic causes associated with spermatogenic failure in Caucasian population. To investigate the distribution of the two genetic defects in Chinese patients with azoospermia or severe oligozoospermia, karyotype analysis by G-banding was carried out in 358 idiopathic infertile men, including 256 patients with azoospermia and 102 patients with severe oligozoospermia, and screening of AZF region microdeletion of Y chromosome by multiplex PCR was performed in those patients without detectable chromosomal abnormality and 100 fertile controls. Of 358 patients, 39(10.9%) were found to have chromosomal abnormalities in which Klinefelter's syndrome (47, XXY) was the most common chromosomal aberration. The incidence of sex chromosomal abnormality in patients with azoospermia was significantly higher than that in patients with severe oligozoospermia (12.1% vs 1%). Among the rest of the 319 patients with normal karyotype, 46 (14.4%) were found to have microdeletions in AZF region. The prevalence rates of AZF microdeletion was 15% and 13.1% in patients with azoospermia and severe oligozoospermia respectively. The microdeletion in AZFc was the most frequent deletion and all the microdeletions in AZFa were found in azoospermic patients. No microdeletion in AZF region was detected in fertile controls. In conclusion, chromosomal abnormality and AZF region microdeletion of Y chromosome might account for about 25% of Chinese infertile patients with azoospermia or severe oligozoospermia, suggesting the two abnormalities are important genetic etiology of spermatogenic failure in Chinese population and it is essential to screen them during diagnosis of male infertility before in vitro assisted fertilization by introcytoplasmic sperm injection.

Adult↗

PubMed2006

DAZ1/DAZ2 cluster deletion mediated by gr/gr recombination per se may not be sufficient for spermatogenesis impairment: a study of Chinese normozoospermic men.

AIM: To explore the possible effect of the deleted in azoospermia (DAZ) copy cluster deletion on spermatogenesis in the Chinese population, the deletion of the azoospermia factor c (AZFc) region was analyzed in 346 normozoospermic men. METHODS: Three DAZ single nucleotide variant loci and seven AZFc-specific sequence-tagged sites were examined with polymerase chain reaction (PCR)-restriction fragment length polymorphism and routine PCR. RESULTS: Five (1.4%) of the normozoospermic men were found to have deletion of gr/gr-DAZ1/DAZ2. None of the men were found to have b2/b4-entire DAZ deletion. CONCLUSION: The presence of gr/gr-DAZ1/DAZ2 deletion in five men with normozoospermia suggests that this deletion per se may not be sufficient for spermatogenic impairment in Chinese men.

Adult↗

PubMed2006

[Study on DAZ gene copy deletion in severe oligozoospermia sperm donor for ICSI].

Deletion of DAZ gene copies is related to spermatogenesis impairment. To investigate the distribution of DAZ gene copy deletions among Chinese men, we analyzed DAZ gene deletions by multiplex polymerase chain reaction (multi-PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 128 infertile patients with severe oligozoospermia selected as semen donors for intracytoplasmic sperm injection (ICSI) and 287 normospermic men. Three patterns of DAZ gene deletions, namely DAZ1/DAZ2 deletion, DAZ3/DAZ4 deletion and complete deletion of all 4 DAZ copies, were found in the present study. Complete deletion of the entire DAZ family of genes was only present in 11.7% of severe oligozoospermic patients. The frequency of DAZ1/DAZ2 deletion was significantly higher in severe oligozoospermic patients than that in the controls(9.4% vs 2.8%, P = 0.004. The total frequency of complete DAZ deletion and DAZ1/DAZ2 deletion was 21.1%. No significant difference in the frequency of DAZ3/DAZ4 deletion was observed between the patient and control group (7.0% vs 3.8%, P > 0.05). These results suggest that complete DAZ deletion is a frequent genetic cause of severe oligozoospermia, and DAZ1/DAZ2 deletion is a high risk factor for the disease. Thus, it is necessary to screen the two deletion patterns of DAZ genes in severely oligozoospermic sperm donors before ICSI during assisted reproduction.

Adult↗

PubMed2006

[The analysis of T cell receptor Vbeta gene usage of cytolytic T-lymphocytes in coxsackievirus B3-induced myocarditis].

OBJECTIVE: To analyze the T cell receptor (TCR) Vbeta gene usage of the cytolytic T-lymphocytes which result in immune-mediated myocyte injury in Coxsackievirus B3-induced myocarditis. METHODS: An experimental murine model with a myocarditic variant of Coxsackievirus B, type 3 has been developed with newborn Balb/c male mice. Mice were killed on day 7 after virus inoculated, which was the time when T cells show significant differentiation. With immunoadsorption, ACTLs, VCTLs, MCTLs are respectively isolated from mesenteric lymph nodes of Balb/c mice suffered from viral myocarditis. T-lymphocytes prepared from mesenteric lymph nodes of uninfected Balb/c mice served as control group. RT-PCR was performed with standard method. The Vbeta gene usage was analyzed by running the electophoresis of PCR products on agarose gel. RESULTS: T cells of control group expressed all Vbeta genes of 20 families. But the TCR VP gene usage of CTLs in experimental groups was markedly restricted. ACTL expressed predominantly Vbeta6, Vbeta8.1, Vbeta8.2, Vbeta8.3, MCTL expressed predominantly Vbeta5.1, Vbeta8.1, Vbeta8.2, Vbeta8.3 and VCTL expressed predominantly Vbeta7, Vbeta8.1, Vbeta8.2, Vbeta8.3. CONCLUSIONS: The TCR Vbeta gene usage of CTLs which result in immune-mediated myocyte injury in Coxsackievirus B3-induced myocarditis is markedly restricted in cells stimulated by specific antigen.

Animals↗

PubMed2006

[Investigation of biodegradable materials as polymeric gene carriers].

This is a study on the biodegradable polymers as gene controlled-released coatings for gene transfer. The PELA (poly (Dl-lactic acid)-co-poly (ethylene glycol), and PLGAE (poly (lactic acid)-co-poly (ethylene glycol)-co-poly (glycolic acid) random copolymer) were synthesized and prepared as the coatings of plasmid pCH110 in the transfection. All kinds of factors affecting the loading efficiency, cytotoxicity, transfection efficiency and the course of the degradation and release in vitro were discussed. The average diameters of microspheres of PELA and PLGAE were 1-3 microm and 0.72 microm respectively. The loading efficiency levels of them were 62% and 70% respectively. The transfection efficiency levels of two kinds of pCH110 delivery system for COS-1 cells were higher and two of them had few cytotoxicity. After transfection, the X-gal assay was performed and reported positive for 96 h. The biodegradable polymeric materials as gene carriers possess their potential superiority.

Biocompatible Materials↗

PubMed2006

[Expression map of immune-related genes on PBMCs in familial clustering patients with chronic virus hepatitis B].

AIM: To investigate peripheral blood mononuclear cells (PBMCs) immune-related gene expression profile in patients with chronic virus hepatitis B(CHB) by oligonucleotide gene array technique. METHODS: PBMCs were collected from the members of a family of clustering hepatitis B virus (HBV) infection including 5 CHB patients and 4 healthy spouses and RNA prepared from PBMCs was hybridized to high-density oligonucleotide arrays(HG-U133A 2.0 Human Gene Chips, Affymetrix), covering the expression of 22 000 human ESTs. Primary scanned image was analyzed with DNT software package. RESULTS: Out of the 22 000 ESTs, 24 different immune-related genes were identified. Among the 24 genes, 7 genes showed increased expression and 17 genes showed decreased expression in CHB compared with those in healthy spouses. The up-regulated genes were mainly associated with adaptive immunity, while the down-regulated genes were associated with innate immunity. CONCLUSION: Our findings suggest that HBV infection alters a broad range of immunity genes expression and innate immunity-associated genes are important in the defense against HBV chronic infection.

Down-Regulation↗

PubMed2006

[The investigation and analysis of the Rh blood type distribution in four kinds of the minority nationalities (Miao, Buyi, Dong and Shui) in Guizhou, China].

OBJECTIVE: To comprehend the Rh blood type distribution and the gene frequency in four main kinds of the minority nationalities in Guizhou, China, so as to supply a scientific foundation for guiding the prevention and cure against the Rh hemolysis illness. METHODS: The irrelative individual blood of the four kinds of the minority nationalities (Miao, Buyi, Dong and Shui) in Guizhou was randomly collected in complete group style and the Rh blood type was identified and analyzed. RESULTS: Totally 15,992 minority nationality people were inspected and checked, and 4851 persons of Han nationality people were chosen as controls. Fifty-one persons were proven as Rh (D)negative individuals, in which, d gene frequency of Miao nationality population was 0.0474 and the Rh negative rate was 0.22%, d gene frequency of Buyi nationality population was 0.0602 and the Rh negative rate was 0.36%, d gene frequency of Dong nationality population was 0.0378 and the Rh negative rate was 0.14%, d gene frequency of Shui nationality population was 0.0307 and the Rh negative rate was 0.09%. d gene frequency of Han nationality population was 0.0574 and the Rh negative rate was 0.33%. In the four minority nationality populations, there was a common characteristic of the highest percentage of expressional type, CCDee type (52.47%-59.66%). At the same time, in the gene frequency of the four minority nationality populations, the CDe frequency was the highest: Miao nationality 0.7244, Buyi nationality 0.7389, Dong nationality 0.7410 and Shui nationality 0.7743. CONCLUSION: The Rh blood type distribution characteristic of the four minority nationality population, Miao, Dong, Buyi and Shui in Guizhou, is similar to that of the minority population in Southern China. The Rh negative rate of Miao, Dong and Shui nationality populations is lower than that of the Han nationality population(0.33%), only the Rh negative rate of Buiyi nationality population is closer or even higher than that of the Han nationality population. So that,the hemolysis illness frequency in the Rh newborn baby of Guizhou minority nationality population is not high.

Asian People↗