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1.
Br J Ophthalmol ; 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31519547

RESUMO

BACKGROUND: Bestrophin-1 (BEST1) gene is associated with a wide range of ocular phenotypes, collectively termed as bestrophinopathy. The aim of the current study was to identify the mutation spectrum of BEST1 in a large cohort of Chinese patients with bestrophinopathy. METHODS: Patients clinically suspected of bestrophinopathy were screened using multigene panel testing. All BEST1 variants were confirmed by Sanger sequencing, and validated in the families. FINDINGS: A total of 92 patients (Best vitelliform macular dystrophy (BVMD)=77; autosomal recessive bestrophinopathy (ARB)=15) from 58 unrelated families of Chinese origin and their available family members (n=65) were recruited. Overall, 39 distinct disease-causing BEST1 variants were identified, including 13 novel variants, and two reported variants but novel for ARB. Of them, 14 were associated with ARB, 23 with BVMD and two (c.604C>T and c.898G>A) with both BVMD and ARB. Most mutations associated with BVMD were missense (97.78%), while ARB was associated with more complex mutations, including missense (88.46%), splicing effect (3.85%), and frameshifts (15.38%). BEST1 hotspots were c.898G>A and c.584C>T among BVMD and ARB patients, respectively. Hot regions were located in exons 8, 2 and 6 in BVMD patients, and in exons 5 and 7 in ARB patients. The overall penetrance of BEST1 in our cohort was 71.30%, no de novo mutations were identified. CONCLUSION: This is the largest study to date that provides major population-based data of the BEST1 mutation spectrum in China. Our results can serve as a well-founded reference for genetic counselling for patients with bestrophinopathy of Chinese origin.

2.
Ophthalmology ; 126(11): 1549-1556, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31054281

RESUMO

PURPOSE: To characterize the genetic landscape of patients with suspected retinitis pigmentosa (RP) in the Chinese population. DESIGN: Cohort study. PARTICIPANTS: A total of 1243 patients of Chinese origin with clinically suspected RP and their available family members (n = 2701) were recruited. METHODS: All patients and available family members were screened using multigene panel testing (including 586 eye disease-associated genes), followed by clinical variant interpretation. MAIN OUTCOME MEASURES: Diagnostic yield, the 17 most commonly implicated genes, age at onset, de novo mutations, and clinical usefulness of genetic testing. RESULTS: Overall, 72.08% of patients received a molecular diagnosis, and the 17 top genes covered 75.63% of diagnostic cases. Diagnostic yield was higher among patients in the early-onset subgroup (≤5 years old, 79.58%) than in the childhood or adolescence-onset subgroup (6-16 years old, 73.74%) and late-onset subgroup (≥17 years old, 65.99%). Moreover, different genes associated with different onset ages and subgroups with different onset ages showed a diverse mutation spectrum. Only 11 de novo mutations (3.18%) were identified. Furthermore, 16.84% of the patients who received a molecular diagnosis had refinement of the initial clinical diagnoses, and the remaining 83.16% received definite genetic subtypes of RP. CONCLUSIONS: This large cohort study provides population-based data of the genome landscape of patients with suspected RP in China. The diagnostic yield was significantly higher than that in previous studies, and the mutation spectrum is completely different with other populations. Genetic testing improves the chance to establish a precise diagnosis, identifies features not previously determined, and allows a more accurate refinement of risk to family members. Our results not only expand the existing genotypic spectrum but also serve as an efficient reference for the design of panel-based genetic diagnostic testing and genetic counseling for patients with suspected RP in China.

3.
Cell Death Dis ; 9(5): 540, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29748605

RESUMO

Glaucoma is a neurodegenerative disease characterized by retinal ganglion cell (RGC) loss, optic disc excavation, and progressive visual field loss. Direct or indirect ameliorating retinal neurodegeneration is a promising therapeutic therapy for glaucoma. Circular RNAs (circRNAs) are a class of covalently closed circular RNA transcripts and have emerged as potential regulators in several neurodegenerative diseases. In this study, we show that cZRANB1 expression is significantly upregulated in retinal neurodegeneration induced by glaucoma. cZRANB1 knockdown decreases retinal reactive gliosis, glial cell activation, and facilitates RGC survival in vivo. cZRANB1 knockdown directly regulates Müller cell function and indirectly regulates RGC function in vitro. cZRANB1 acts as miRNA sponge to regulate Müller cell function through cZRANB1/miR-217/RUNX2 network. Intervention of cZRANB1 expression would become an effective strategy for treating retinal neurodegeneration.

4.
Mol Vis ; 23: 605-613, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28867931

RESUMO

PURPOSE: Familial exudative vitreoretinopathy (FEVR) is a genetically and clinically heterogeneous disease, characterized by failure of vascular development of the peripheral retina. The symptoms of FEVR vary widely among patients in the same family, and even between the two eyes of a given patient. This study was designed to identify the genetic defect in a patient cohort of ten Chinese families with a definitive diagnosis of FEVR. METHODS: To identify the causative gene, next-generation sequencing (NGS)-based target capture sequencing was performed. Segregation analysis of the candidate variant was performed in additional family members by using Sanger sequencing and quantitative real-time PCR (QPCR). RESULTS: Of the cohort of ten FEVR families, six pathogenic variants were identified, including four novel and two known heterozygous mutations. Of the variants identified, four were missense variants, and two were novel heterozygous deletion mutations [LRP5, c.4053 DelC (p.Ile1351IlefsX88); TSPAN12, EX8Del]. The two novel heterozygous deletion mutations were not observed in the control subjects and could give rise to a relatively severe FEVR phenotype, which could be explained by the protein function prediction. CONCLUSIONS: We identified two novel heterozygous deletion mutations [LRP5, c.4053 DelC (p.Ile1351IlefsX88); TSPAN12, EX8Del] using targeted NGS as a causative mutation for FEVR. These genetic deletion variations exhibit a severe form of FEVR, with tractional retinal detachments compared with other known point mutations. The data further enrich the mutation spectrum of FEVR and enhance our understanding of genotype-phenotype correlations to provide useful information for disease diagnosis, prognosis, and effective genetic counseling.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Mutação de Sentido Incorreto , Doenças Retinianas/genética , Deleção de Sequência , Tetraspaninas/genética , Adolescente , Adulto , China/epidemiologia , Estudos de Coortes , Análise Mutacional de DNA , Oftalmopatias Hereditárias , Feminino , Estudos de Associação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Adulto Jovem
5.
Circulation ; 136(17): 1629-1642, 2017 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-28860123

RESUMO

BACKGROUND: The vascular complications of diabetes mellitus are the major causes of morbidity and mortality among people with diabetes. Circular RNAs are a class of endogenous noncoding RNAs that regulate gene expression in eukaryotes. In this study, we investigated the role of circular RNA in retinal vascular dysfunction induced by diabetes mellitus. METHODS: Quantitative polymerase chain reactions, Sanger sequencing, and Northern blots were conducted to detect circular HIPK3 (circHIPK3) expression pattern on diabetes mellitus-related stresses. MTT (3-[4,5-dimethythiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assays, EdU (5-ethynyl-2'-deoxyuridine) incorporation assays, Transwell migration assays, and Matrigel assays were conducted to detect the role of circHIPK3 in retinal endothelial cell function in vitro. Retinal trypsin digestion, vascular permeability assays, and ELISA assays were conducted to detect the role of circHIPK3 in retinal vascular dysfunction in vivo. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were conducted to reveal the mechanism of circHIPK3-mediated retinal vascular dysfunction. RESULTS: circHIPK3 expression was significantly upregulated in diabetic retinas and retinal endothelial cells following stressors related to diabetes mellitus. circHIPK3 silencing or overexpressing circHIPK3 changed retinal endothelial cell viability, proliferation, migration, and tube formation in vitro. circHIPK3 silencing in vivo alleviated retinal vascular dysfunction, as shown by decreased retinal acellular capillaries, vascular leakage, and inflammation. circHIPK3 acted as an endogenous miR-30a-3p sponge to sequester and inhibit miR-30a-3p activity, which led to increased vascular endothelial growth factor-C, FZD4, and WNT2 expression. Ectopic expression of miR-30a-3p mimicked the effect of circHIPK3 silencing on vascular endothelial phenotypes in vivo and in vitro. CONCLUSIONS: The circular RNA circHIPK3 plays a role in diabetic retinopathy by blocking miR-30a function, leading to increased endothelial proliferation and vascular dysfunction. These data suggest that circular RNA is a potential target to control diabetic proliferative retinopathy.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/metabolismo , Células Endoteliais/metabolismo , RNA não Traduzido/metabolismo , Vasos Retinianos/metabolismo , Animais , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Retinopatia Diabética/genética , Retinopatia Diabética/patologia , Células Endoteliais/fisiologia , Receptores Frizzled/biossíntese , Receptores Frizzled/genética , Regulação da Expressão Gênica , Masculino , Camundongos , MicroRNAs/biossíntese , MicroRNAs/genética , RNA não Traduzido/genética , Vasos Retinianos/patologia , Fator C de Crescimento do Endotélio Vascular/biossíntese , Fator C de Crescimento do Endotélio Vascular/genética , Proteínas Wnt/biossíntese , Proteínas Wnt/genética
6.
Front Genet ; 8: 107, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28890726

RESUMO

Purpose: To show early, rapid and accurate molecular diagnosis of occult macular dystrophy (OMD) in a four-generation Chinese family with inherited macular dystrophy. Methods: In the current study, we comprehensively screened 130 genes involved in common inherited non-syndromic eye diseases with next-generation sequencing-based target capture sequencing of the proband of a four-generation Chinese family that has suffered from maculopathy without a definitive diagnosis for over 10 years. Variants were filtered and analyzed to identify possible disease-causing variants before validation by Sanger sequencing. Results: Two heterozygous mutations-RP1L1 c.133 C > T (p.Arg45Trp), which is a hot spot for OMD, and ABCA4 c.6119 G > A (p.Arg2040Gln), which was identified in Stargardt's disease were found in three patients, but neither of the mutations was found in the unaffected individuals in the same family, who are phenotypically normal or in the normal control volunteers. Conclusion: These results cannot only confirm the diagnosis of OMD in the proband, but also provide presymptomatic diagnosis of the proband's children before the onset of visual acuity impairment and guidance regarding the prognosis and management of these patients. Heterozygous mutations of RP1L1 c.133 C > T (p.Arg45Trp) and ABCA4 c.6119 G > A (p.Arg2040Gln) are likely responsible for OMD. Our results further extend our current understanding of the genetic basis of OMD, and emphasize the importance of molecular diagnosis and genetic counseling for OMD.

7.
Front Mol Neurosci ; 10: 285, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28936163

RESUMO

Glaucoma is a progressive neuropathy characterized by the loss of retinal ganglion cells (RGCs). Strategies that delay or halt RGC loss have been recognized as potentially beneficial for rescuing vision in glaucoma patients. Quercetin (Qcn) is a natural and important dietary flavonoid compound, widely distributed in fruits and vegetables. Mounting evidence suggests that Qcn has numerous neuroprotective effects. However, whether Qcn exerts neuroprotective effects on RGC in glaucoma is poorly understood. In this study, we investigated the protective effect of Qcn against RGC damage in a rat chronic ocular hypertension (COHT) model invivo and hypoxia-induced primary cultured RGC damage in vitro, and we further explored the underlying neuroprotective mechanisms. We found that Qcn not only improved RGC survival and function from a very early stage of COHT invivo, it promoted the survival of hypoxia-treated primary cultured RGCs invitro via ameliorating mitochondrial function and preventing mitochondria-mediated apoptosis. Our findings suggest that Qcn has direct protective effects on RGCs that are independent of lowering the intraocular pressure (IOP). Qcn may be a promising therapeutic agent for improving RGC survival and function in glaucomatous neurodegeneration.

8.
Front Mol Neurosci ; 10: 76, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28367115

RESUMO

Mesencephalic astrocyte-derived neurotrophic factor (MANF), a newly discovered secreted neurotrophic factor, has been proven to not only protect dopaminergic neurons and other cell types but also regulate neuroinflammation and the immune response to promote tissue repair and regeneration. However, to date, there is no information regarding the relationship between MANF and retinal ganglion cells (RGCs) in the eye. In the current study, we first determined the expression of MANF in the retina and vitreous. Then, we examined the effect of MANF on RGCs using both in vivo and in vitro models and simultaneously explored the underlying neuroprotective mechanisms of MANF. Finally, we measured the concentrations of MANF in the vitreous of patients with different retinopathies. We demonstrated that MANF was highly expressed in RGCs and that exogenous MANF could protect RGCs from hypoxia-induced cell injury and apoptosis both in vitro and in vivo by preventing endoplasmic reticulum stress-mediated apoptosis. Furthermore, MANF can be detected in the vitreous humor, and the concentration changed under pathological conditions. Our results provide important evidence that MANF may be a potential therapeutic protein for a range of retinal pathologies in either the preclinical stage or after diagnosis to promote the survival of RGCs. Vitreous MANF may be a promising protein biomarker for the indirect assessment of retinal disorders, which could provide indirect evidence of retinal pathology.

9.
Case Rep Infect Dis ; 2017: 7052908, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28286681

RESUMO

Mycobacteria, which are known as rapidly growing bacteria, are pathogens that are responsible for cutaneous or subcutaneous infections that especially occur after injection, trauma, or surgery. In this report, we describe a species of Mycobacterium abscessus that was isolated from a breast abscess in a patient who was previously diagnosed with granulomatous lobular mastitis (GLM). This current case is the first ever presented case of GLM associated with M. abscessus documented in South China. The case presentation highlights the role of M. abscessus in GLM. The association of M. abscessus and GLM is discussed and a summary of breast infection due to Mycobacteria is given.

11.
Front Cell Neurosci ; 10: 254, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27932951

RESUMO

Purpose: Our previous study indicated that mitochondrial DNA (mtDNA) damage and mutations are crucial to the progressive loss of retinal ganglion cells (RGCs) in a glaucomatous rat model. In this study, we examined whether high pressure could directly cause mtDNA alterations and whether the latter could lead to mitochondrial dysfunction and RGC death. Methods: Primary cultured rat RGCs were exposed to 30 mm Hg of hydrostatic pressure (HP) for 12, 24, 48, 72, 96 and 120 h. mtDNA alterations and mtDNA repair/replication enzymes OGG1, MYH and polymerase gamma (POLG) expressions were also analyzed. The RGCs were then infected with a lentiviral small hairpin RNA (shRNA) expression vector targeting POLG (POLG-shRNA), and mtDNA alterations as well as mitochondrial function, including complex I/III activities and ATP production were subsequently studied at appropriate times. Finally, RGC apoptosis and the mitochondrial-apoptosis pathway-related protein cleaved caspase-3 were detected using a Terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay and western blotting, respectively. Results: mtDNA damage was observed as early as 48 h after the exposure of RGCs to HP. At 120 h after HP, mtDNA damage and mutations significantly increased, reaching >40% and 4.8 ± 0.3-fold, respectively, compared with the control values. Twelve hours after HP, the expressions of OGG1, MYH and POLG mRNA in the RGCs were obviously increased 5.02 ± 0.6-fold (p < 0.01), 4.3 ± 0.2-fold (p < 0.05), and 0.8 ± 0.09-fold (p < 0.05). Western blot analysis showed that the protein levels of the three enzymes decreased at 72 and 120 h after HP (p < 0.05). After interference with POLG-shRNA, the mtDNA damage and mutations were significantly increased (p < 0.01), while complex I/III activities gradually decreased (p < 0.05). Corresponding decreases in membrane potential and ATP production appeared at 5 and 6 days after POLG-shRNA transfection respectively (p < 0.05). Increases in the apoptosis of RGCs and cleaved caspase-3 protein expression were observed after mtDNA damage and mutations. Conclusions: High pressures could directly cause mtDNA alterations, leading to mitochondrial dysfunction and RGC death.

12.
Zhen Ci Yan Jiu ; 41(2): 138-43, 2016 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-27323441

RESUMO

OBJECTIVE: To observe the effect of electroacupuncture (EA) on behavior changes and the adundance levels of transforming growth factor beta 3 (TGF-beta 3) and basic fibroblast growth factor (bFGF) proteins in the hippocampus of rats with chronic unpredictable mild stress (CUMS)-induced depression, so as to explore its mechanisms underlying improvement of depression. METHODS: Forty Sprague-Dawley rats were randomly divided into the following groups: control, model, EA, and medication (Fluoxetine), n = 10 in each group. The depression model was established by CUMS combined with solitary raising for 28 days. EA (2 Hz, 0.6 mA) was applied to "Baihui" (GV 20) and "Yintang" (GV 29) for 20 mm, once daily before CUMS every day. The rats of the medication group were given with Fluoxetine (10 mg/kg, 5 mL/kg) before CUMS every day. The behavioral changes (crossing and rearing locomotion) were detected by using open field tests. The expression levels of TGF-beta 3 and bFGF proteins of the bilateral hippocampus tissues were detected using biotin label-based antibody protein chips. Results Compared to the control group, the crossed grid-square numbers and rearing times were significantly decreased in the model group (P<0.01). Following EA and medication interventions, the CUMS induced decreases of the crossed grid-square number and rearing times were notably reversed in both EA and medication groups (P<0.01), suggesting an amelioration of depression after the intervention. The relative expression level of hippocampal TGF-beta 3 was down-regulated (fold change = 0.48, vs. the control group) and that of bFGF up-regulated (fold change= 1.36, vs the control group) in the model group. In both the EA and medication groups, the down-regulated TGF-beta 3 expression and the up-regulated bFGF protein expression were suppressed (TGF-beta 3: fold change = 1.61, 1.6 and bFGF: fold change = 0.61, 0.45, vs. the model group respectively). CONCLUSION: EA can improve the depression-like state in depression rats which may be associated with its effect in up-regulating hippocampal TGF-beta 3 protein level and down-regulating bFGF protein expression via promoting neurogenesis.


Assuntos
Depressão/terapia , Eletroacupuntura , Fator 2 de Crescimento de Fibroblastos/metabolismo , Hipocampo/metabolismo , Fator de Crescimento Transformador beta3/metabolismo , Pontos de Acupuntura , Animais , Depressão/genética , Depressão/metabolismo , Depressão/psicologia , Fator 2 de Crescimento de Fibroblastos/genética , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Fator de Crescimento Transformador beta3/genética
13.
Zhen Ci Yan Jiu ; 41(1): 18-23, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-27141615

RESUMO

OBJECTIVE: To observe the effect of acupuncture on c-jun N-terminal Kinase (JNK) signaling in the hippocampus in rats with forced-swimming stress, so as to reveal its underlying mechanism in relieving depression-like motor response. METHODS: Forty-eight Sprague-Dawley rats were randomly divided into 8 groups as control, control + JNK inhibitor (SP 600125) , model, model + SP 600125, acupuncture, acupuncture + SP 600125, Fluoxetine (an anti-depressant) , and Fluoxetine + SP 600125 (n = 6 in each group). The depression-like behavior (immobility) model was established by forcing the rat to swim in a glass-cylinder and solitary raise. Acupuncture stimulation was applied to "Baihui" (GV-20) and "Yintang" (GV 29) for 20 min before forced swimming and once again 24 h later.. The rats of the Fluoxetine and Fluoxetine+ SP 600125 groups were treated by intragastric administration of fluoxetine 10 mL (1.8 mg)/kg before forced swimming and once again 24 h thereafter. The rats of the model + SP 600125 and acupuncture + SP 600125 groups were treated by intraperitoneal injection of SP 600125 (10 mg/kg) 90 min before forced swimming and 30 min before acupuncture intervention, respectively. The immobility duration of rats in the water glass-cylinder was used to assess their depression-like behavior response. The expression levels of protein kinase kinase 4 (MKK 4), MKK 7, JNK, and phosphorylated JNK (p-JNK) in the hippocampus were detected by Western blot. RESULTS: Compared to the control group, the duration of immobility, and the expression levels of hippocampal MKK 4, MKK 7, and p-JNK proteins were significantly increased in the model group (P < 0.01). While in comparison with the model group, the duration of immobility in the model + SP 600125, acupuncture, acupuncture + SP 600125, Fluoxetine and Fluoxetine + SP 600125 groups, the expression levels of hippocampal MKK 4 and MKK 7 proteins in the Fluoxetine + SP 600125 group, and those of p-JNK protein in the acupuncture, acupuncture + SP 600125, model + SP 600125, Fluoxetine and Fluoxetine + SP 600125 groups were considerably decreased (P < 0.05, P < 0.01). No significant differences were found between the control and control + SP 600125 groups and among the model + SP 600125, acupuncture, acupuncture + SP 600125, Fluoxetine and Fluoxetine + SP 600125 groups in the duration of immobility (P > 0.05), and in the expression level of p-JNK protein (P > 0.05). No significant changes were found in the expression levels of JNK among the 8 groups (P > 0.05). CONCLUSION: Acupuncture stimulation of GV 20 and GV 29 is effective in relieving depression-like motor response in forced-swimming stress rats, which may be closely associated with its effects in down-regulating the expression of hippocampal p-JNK protein.


Assuntos
Terapia por Acupuntura , Depressão/terapia , Hipocampo/enzimologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Pontos de Acupuntura , Animais , Depressão/enzimologia , Depressão/genética , Depressão/psicologia , Hipocampo/metabolismo , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Masculino , Ratos , Ratos Sprague-Dawley , Natação
14.
Front Hum Neurosci ; 10: 686, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28154531

RESUMO

Mesencephalic astrocyte-derived neurotrophic factor (MANF), otherwise named Arginine-Rich, Mutated in Early-stage Tumors (ARMET), is a secretory endoplasmic reticulum stress (ERS) protein that is widely expressed in mammalian tissues. To date, little is known about the distribution and expression of MANF in the retina and optic nerve (ON). Therefore, we studied the expression and distribution of MANF in the ON and retina by real-time PCR, immunofluorescence staining and western blotting. Results from rat and mouse were highly consistent in the retina. MANF was detected in both tissues in rat, wherein it was principally localized to the ganglion cell layer (GCL), followed by the inner nuclear layer (INL). The MANF protein levels in the rat retina were 3.33-fold higher than in the rat ON. Additionally, MANF was robustly expressed by retinal ganglion cells (RGCs) in the human retina. In human ON, MANF was partially co-localized with glial fibrillary acidic protein (GFAP), suggesting that it was not restricted to astrocytes. In vitro studies confirmed that MANF could be robustly expressed in RGCs and was found principally within the cytoplasm. Hypoxia can stimulate up-regulation by of MANF expression over time, suggesting that MANF may play a vital role in the functional regulation of RGCs both in health and disease. We believe that the present study improves our understanding of the distribution and expression of MANF in the retina and ON and could help in further analysis of its interact and correlate with the relevant ophthalmic diseases.

15.
Neurobiol Dis ; 74: 167-179, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25478814

RESUMO

Glaucoma is a chronic neurodegenerative disease characterized by the progressive loss of retinal ganglion cells (RGCs). Mitochondrial DNA (mtDNA) alterations have been documented as a key component of many neurodegenerative disorders. However, whether mtDNA alterations contribute to the progressive loss of RGCs and the mechanism whereby this phenomenon could occur are poorly understood. We investigated mtDNA alterations in RGCs using a rat model of chronic intraocular hypertension and explored the mechanisms underlying progressive RGC loss. We demonstrate that the mtDNA damage and mutations triggered by intraocular pressure (IOP) elevation are initiating, crucial events in a cascade leading to progressive RGC loss. Damage to and mutation of mtDNA, mitochondrial dysfunction, reduced levels of mtDNA repair/replication enzymes, and elevated reactive oxygen species form a positive feedback loop that produces irreversible mtDNA damage and mutation and contributes to progressive RGC loss, which occurs even after a return to normal IOP. Furthermore, we demonstrate that mtDNA damage and mutations increase the vulnerability of RGCs to elevated IOP and glutamate levels, which are among the most common glaucoma insults. This study suggests that therapeutic approaches that target mtDNA maintenance and repair and that promote energy production may prevent the progressive death of RGCs.


Assuntos
Dano ao DNA , DNA Mitocondrial , Glaucoma/genética , Glaucoma/fisiopatologia , Mutação , Células Ganglionares da Retina/fisiologia , Animais , Apoptose/fisiologia , Axônios/patologia , Axônios/fisiologia , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Reparo do DNA , Modelos Animais de Doenças , Progressão da Doença , Glaucoma/patologia , Ácido Glutâmico/metabolismo , Pressão Intraocular/genética , Pressão Intraocular/fisiologia , Masculino , Mitocôndrias/genética , Mitocôndrias/patologia , Mitocôndrias/fisiologia , Nervo Óptico/patologia , Nervo Óptico/fisiopatologia , Ratos Wistar , Células Ganglionares da Retina/patologia , Fatores de Tempo
16.
Sheng Li Xue Bao ; 66(5): 511-8, 2014 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-25331996

RESUMO

The knowledge about electrophysiological properties of retinal ganglion cells (RGCs), as well as modulation of these properties, is important not only for understanding the unique physiological functions of RGCs under normal conditions, but also for exploring the cellular mechanisms of retinal neurodegeneration diseases, such as glaucoma. In this paper, we reviewed the progress in electrophysiological studies of RGCs by using patch-clamp techniques, concerning the voltage-gated ion channels, the ligand-gated ion channels and the effects of neuromodulators on these channels.


Assuntos
Fenômenos Eletrofisiológicos , Células Ganglionares da Retina/fisiologia , Animais , Humanos , Canais Iônicos/fisiologia , Técnicas de Patch-Clamp
17.
Sheng Li Xue Bao ; 65(6): 654-63, 2013 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-24343724

RESUMO

In the vertebrate retina, Müller cells are principal glial cells which stretch across the whole thickness of the retina and contact with the somata and processes of all retinal neurons, thus forming an anatomical and functional link between glial cells and retinal neurons. Numerous studies have shown that Müller cells express various neurotransmitter receptors, transporters, ion channels and enzymes that are relative to cellular activities. In addition, the cells also release factors, such as D-serine and glutamate etc., to regulate the neuron excitability. Therefore, retinal Müller cells may play more curious roles in addition to supporting the retinal neurons. The information exchange and interaction between Müller cells and neurons may regulate and maintain retinal neuronal functions. In the glaucomatous retina, Müller cells are reactivated (gliosis). Reactivated Müller cells undergo a variety of changes in cellular physiology, biochemistry and morphological features. Meanwhile, the reactivated Müller cells may produce and release cytotoxic factors, such as nitric oxide (NO), tumor necrosis factor-α (TNF-α), reactive oxygen species (ROS) and prostaglandin E2 (PGE2), thus involving in the induction of retinal ganglion cell apoptosis and death. Here, we reviewed the physiological properties of retinal Müller cells, and the functional changes of Müller cells in the glaucomatous retina.


Assuntos
Células Ependimogliais/patologia , Células Ependimogliais/fisiologia , Glaucoma/fisiopatologia , Humanos , Neurônios/fisiologia , Retina/citologia
18.
Neurosci Lett ; 554: 99-104, 2013 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-24025791

RESUMO

Elevated intraocular pressure (IOP) is considered as the major risk factor for the loss of retinal ganglion cells (RGCs) and their axons in glaucoma. Emerging evidence suggests elevated IOP can induce Drp1 upregulation and mitochondrial fission, which is involved in cell death. However, the underlying mechanism for these effects remains unknown. The present study used RNAi screening to investigate the effects of 24 kinases associated with mitochondrial activities on DRP1 expression under hydrostatic pressure. We identified, for the first time, that glycogen synthase kinase 3 beta (GSK3ß) knockdown suppressed the upregulation of DRP1 induced by elevated pressure. Use of the pharmacological inhibitor of GSK3ß inhibitor, lithium chloride (LiCl), confirmed this result. Furthermore, we demonstrated that one of the mechanisms of lithium chloride neuroprotection might be via inhibition of mitochondrial fission through downregulation of Drp1.


Assuntos
Dinaminas/metabolismo , Quinase 3 da Glicogênio Sintase/metabolismo , Cloreto de Lítio/farmacologia , Fármacos Neuroprotetores/farmacologia , Interferência de RNA , Epitélio Pigmentado da Retina/efeitos dos fármacos , Animais , Células Cultivadas , Regulação para Baixo , Dinaminas/genética , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Técnicas de Silenciamento de Genes , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Quinase 3 da Glicogênio Sintase/genética , Glicogênio Sintase Quinase 3 beta , Humanos , Pressão Hidrostática , Dinâmica Mitocondrial , Cultura Primária de Células , Ratos Wistar , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/metabolismo
19.
Nanoscale ; 5(7): 2983-9, 2013 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-23455229

RESUMO

We report a new capping-agent-free strategy for the synthesis of substrate-supported porous icosahedral Au nanoparticles (NPs) with rough naked surfaces, based on the crystallization from substrate-supported thin solution layers followed by solid-phase thermolysis. The plasmonic properties of icosahedral Au NPs have been studied using single particle dark-field scattering microscopy and spectroscopy. The two distinct localized surface plasmon resonance (LSPR) bands observed in the single particle dark-field spectra can be ascribed to the quadrupole resonance at ca. 425 nm and the size-dependent dipole resonance in the red region (645-708 nm). The unique rough naked surface, the facile synthesis, together with the ability to control the nanoparticle size and to vary the LSPR frequency in the red region, would make the substrate-supported porous icosahedral Au NPs promising on multiple levels in the applications of catalysis, ultrasensitive biosensors, and in surface-enhanced Raman scattering (SERS).

20.
Food Chem ; 138(1): 396-405, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23265504

RESUMO

Four principal mango cultivars (Tainong No.1, Irwin, JinHwang and Keitt) grown in southern China were selected, and their physico-chemical and antioxidant properties were characterized and compared. Of all the four cultivars, Tainong No.1 had highest content of total phenols, ρ-coumaric acid, sinapic acid, quercetin, titratable acidity, citric acid, malic acid, fructose, higher antioxidant activities (DPPH, FRAP) and L(*), lower pH, PPO activity and individual weight. Keitt mangoes showed significantly (p<0.05) higher contents of ß-carotene, ρ-hydroxybenzoic acid, sucrose, total sugar, total soluble solid, catechin, succinic acid and higher PPO activity. JinHwang mangoes exhibited significantly (p<0.05) higher individual weight and PPO activity, but had lower content of total phenols, ß-carotene and lower antioxidant activity. Principal component analysis (PCA) allowed the four mango cultivars to be differentiated clearly based on all these physico-chemical and antioxidant properties determined in the study.


Assuntos
Antioxidantes/análise , Frutas/química , Mangifera/química , Extratos Vegetais/análise , China , Fenóis/análise , beta Caroteno/análise
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