The pGenesil-1-Beclin1 eukaryotic expression vectors were constructed to establish an SH-SY5Y cell line stably expressing shRNA-Beclin1. The shRNA was connected to pGenesil-1 to construct the recombinant plasmid pGenesil-1-Beclin1, which was transformed into JM109 E.coli. Positive clones were identified by digestion with restriction endonuclease and DNA sequencing. SH-SY5Y cells were cultured by the conventional method. The pGenesil-1-Beclin1 and pGenesil-1 plasmids were transfected into SH-SY5Ycells, and the cells were screened by G418 until the stable G418-resistant monoclonal cells were acquired. Beclin1 mRNA and Beclin1 protein were detected by RT-PCR and Western blot analysis respectively. The results of restriction endonuclease analysis and DNA sequencing confirmed the correct construction of the eukaryotic expression vector pGenesil-1-Beclin1. Two SH-SY5Y transfected cell lines were successfully selected. Compared with the control group, RT-PCR and Western blot showed that the expression of Beclin1 mRNA and protein were down regulated 71.28%±1.45%(P<0.05)and 75.50%±2.63%(P<0.05), respectively. The results indicated that the eukaryotic expression vector pGenesil-1-Beclin1 was successfully constructed and the SH-SY5Y cell lines with inhibited Beclin1 expression were established. It provides a useful cell model for studying the biological function of Beclin1.
Objective To observe the expression and relationship of high-mobility group A(HMGA)1, HMGA2, MIB-1 labeling index (LI) and let-7 in retinoblastoma (RB). Methods Forty-four RB samples were studied, including 11 poorly-differentiated samples, 33 well-differentiated samples; eight invasive and 36 non-invasive samples. The expression of HMGA1, HMGA2 and MIB-1 LI in RB were analyzed by immunohistochemitry. The HMGA1, HMGA2 were scored on a scale of 0 to high expression. 0: no expression; low: 1%-10%; medium: 11%-50%; high: ＞50%. The MIB LI were scored on a scale of 0 to high expression. 0: no expression; low: 1%-40%; high: ＞40%. Semiquantitative reverse transcription-polymerase chain reaction was used to assay the let-7 expression level: ge;80% showed no significantly decreased expression; 60%-79% showed medium decrease in expression; ＜60% highly decreased in expression. ResultsIn 44 RB samples, there were 14 cases with no HMGA1 expression (32%), 11 cases with low expression (25%), 10 cases with medium expression (23%), and nine cases with high expression (20%). Expression level of HMGA1 was significantly higher in poorly differentiated RB than in well-differentiated RB (chi;2=11.3,P＜0.01); however, no statistically significant difference was found between invasive tumors and noninvasive tumors (chi;2=5.9,P＞0.05). There were 11 cases with no HMGA2 expression (25%), 11 cases with low expression (25%), nine cases with medium expression (20%), and 13 cases with high expression (30%). Expression level of HMGA2 was significantly higher in poorly differentiated and invasive RB than in well-differentiated and noninvasive RB respectively (chi;2=20.9, 8.7;P＜0.05). There were 4 cases with no MIB-1 LI expression (9%), 18 cases with low expression (41%), and 22 cases with high expression (50%). Expression level of MIB-1 LI was significantly higher in poorly differentiated RB than in well-differentiated RB (t=5.2,P＜0.05). Higher expression of MIB-1 LI was found in invasive tumors than in noninvasive tumors, with no significant difference (t=-1.1,P＞0.05). Twenty-seven cases had no significantly decreased expression of let-7 (61%). There were eight cases with medium decreased expression (18%) and nine cases with highly decreased expression (21%). Correlation analyses revealed that MIB-1 LI expression significantly correlated with HMGA1and HMGA2 proteins (r=0.327, 0.602;P＜0.05). A significantly inverse correlation existed between let-7 expression and HMGA1, HMGA2 proteins and MIB-1 LI respectively (r=-0.247,-0.310,-0.392;P＜0.05). Conclusions Overexpression of HMGA1, HMGA2 and MIB-1 LI and down regulation of let-7 were demonstrated in RB. Supplying let-7 to RB cells can possibly inhibit HMGA1 and HMGA2 expression.
Objective To investigate the effect of apoptosis-related gene p53 on the apoptosis of retinal capillary cells in rats with spontaneously hypertensive (SHR) after ischemic reperfusion injury. Methods A total of 60 SHR rats were randomly divided into sham group (SHR-SH) and retinal ischemic reperfusion group (SHRRIR), which were subdivided into 5 subgroups according to the time after RIR: 2, 6, 24, and 72 hours and 7 days, with 6 rats in each subgroup. Another 60 Wistar-Kyoto (WKY) rats were divided into the same groups as the SHR rats as the control. The RIR model was set up. The apoptosis of retinal capillary cells was detected by terminal deoxynucleotidyl transferasemediated dUTP nick end labeling (TUNEL) methods and the expression of p53 was determined by streptavidin-perosidase (SP) immunohistochemistry. Results The apoptosis rate of retinal capillary cells in the 5 SHRRIR groups was (8.64plusmn;0.56)%, (14.92plusmn;0.99)%, (24.72plusmn;2.98)%, (16.53plusmn;1.80)%, and (7.12plusmn;1.10)%, respectively. The expression of p53 in SHRRIR groups increased at the 2nd hour after RIR, reached the peak at the 24th hour, kept the high level at the 72nd hour, and remained a little at the 7th day, which was significantly different from which in the SHRSH groups (Plt;0.01). The expression of p53 were higher in SHR-IR groups than that in the WKY-RIR groups (Plt;0.01). Conclusions p53 may play a part in RIR injury by inducing or promoting apoptosis. The apoptosis of retinal capillary cells after RIR is more severe under the hypertension, and reaches the peak at the 24 hour after RIR.
The debate on the cell of origin of human retinoblastoma lasted for more than one century. In the recent issue of ldquo;cellrdquo;, David Cobrinikprime;s group shows that L/M cone precursors are the most likely answer as they have an intrinsic circuitry, including murine double minute 2 (MDM2), Nmyc, the nuclear receptors retinoid X receptor and thyroxine receptor 2, making them extremely sensitive to transformation following retinoblastoma gene inactivation.
Objective To evaluate the inhibited effects of small interfering RNA targeting Rac1 (Rac1-siRNA) on rat retinal neovascularization in retinae. Methods Retinal vein occlusion was induced by retinal photodynamic medthod in 25 Sprague-Dawley rats. Rac1-siRNA vector DNA was injected into the vitrous of one eye of those rats (gene intervention group), and empty vector DNA was injected into the fellow eye (blank control group). Rac1-siRNA vector was injected in other 25 SD rats without retinal vein occlusion (blank intervention group). Two weeks after injection, fluorescein isothiocyanate (FITC)-dextran was perfused into the hearts of all the rats, and the retinal wholemount was made to observe the neovascularization. The numbers of endothelial cells which break through the internal limiting membrane were counted after hematoxylin-eosin staining. Results A massive of neovascularization and FITC leakage were found in blank control group. Small part of neovascularization and a little FITC leakage were observed in the gene intervention group. Retinal vessels were normal in blank intervention group. Compared with blank contrast group and blank intervention group, the difference of the mean numbers of endothelial cells which broke through the internal limiting membrane in the gene intervention group was significant（t=? P=0.000??lt;0.05）. Conclusion Rac1-siRNA can inhibit retinal neovascularization induced by retinal vein occlusion in rats.
Objective To make the diagnosis of a pedigree of X-linked congenital stational night blindness(CSNB) and to identify the disease-causing gene. Methods Clinical examination and family analysis were made. Venous blood was drawn from 5 affected and 16 unaffected individuals from the family. Genomic DNA was extracted. The locus of the candidate gene was mapped by linkage study. Mutation was screened by polymerase chain reaction (PCR) of the candidate gene exons and flanked introns. The PCR products are directly sequenced. The healthy people in and out of the family who were selected according to certain standards were as the control. Results A Chinese family with X-linked complete congenital stationary night blindness (CSNB1) was diagnosed. A missense mutation A772C (T258P) in exon 2 of NYX gene was identified in all affected patients and all female carriers were heterozygous. This mutation was neither found in normal family members nor among 110 unrelated normal controls. Conclusion A novel mutation of NYX gene with threonine to proline change is responsible for this Chinese CSNB1 family. (Chin J Ocul Fundus Dis, 2007, 23: 184-188)
Despite its low incidence, retinoblastoma and its rela ted gene (Rb gene) have attracted some of the most brilliant minds in medicine and biology fi elds over the past years. Great advances have been achieved in the tumoregenesis mechanism and clinical management of retinoblastoma recently. However as always , more questions arise from those results. In order to improve retinoblastoma re search in China, we need to strengthen the communication and cooperation with di ffe rent countries, different institutes and disciplines, and utilize the great reso urces of retinoblastoma patients in China.
Objective To observe the mutation frequency and the characteristics of rentinitis pigmentosa (RP)1 gene in the Chinese patients with autosomal dominant (AD) RP or sporadic RP (SRP), and to evaluate their potential effects on the pathogenesis of RP. Methods Fifty-five members from 7 Chinese families with ADRP, 30 patients with SRP, and 75 healthy adults were recruited. Polymerase chain reaction (PCR) and direct DNA sequencing were used to detect the sequence mutation in the entire coding region and splice sites of RP1 gene. Univariate analysis and multivariate analysis were used to detect the effect of RP1 gene mutation sites on RP. Results Four coding sequence variants were detected in the codes of 852，872，921 and 939 at the exon 4 of RP1 gene. The R872H alteration, which was found in both ADRP families and patients with SRP, showed positive correlation with RP confirmed by the multivariate logistic regression analysis. The P903L alteration was only found in ADRP families but not in the patients with SRP or the healthy adults. Conclusions The R872H alteration in the RP1 gene is likely to increase the risk of RP, and may be a susceptible gene of RP. Whether the P903L alteration is a diseasecausing factor needs to be further studied.
Objective To investigate the mutations of the gene in Chinese patients with X linked juvenile retinoschisis (XLRS), and to provide the genetic diagnosis and consultation of heredity for the patients and their families. Methods Genomic DNA was isolated from leukocytes of 29 male patients with XLRS, 38 female carriers and 100 normal controls (the patients and the carriers were from 12 families). All 6 exons of XLRS1 gene were amplified by polhism (SSCP) assay. The positions and types of XLRS1 gene mutations were determined by direct sequencing. Results Eleven different XLRS1 mutations were identified in these 12 families, including one frameshift mutation due to base loss of the first exon: c.22delT（L9CfsX20）, one nonsense mutation due to base loss of the first exon (Trp163X), one splice donor site mutation(c.52+2 Trarr;C; IVS1+2T to C), and eight missense mutation due to base replacement（Ser73Pro, Arg102Gln, Asp145His, Arg156Gly, Arg200Cys, Arg209His, Arg213Gln, and Cys223Arg). No gene mutation was detected in the control group. Four new mutations included frmaeshift mutation（L9CfsX20）and mutations of Asp145His, Arg156Gly, and Trp163X at the fifth exon. A newly discovered non-disease-related polymorphism (NSP) was the c.576C to T (Pro192Pro) change at the sixth exon. Conclusion Eleven different XLRS1 mutations were detected, which is the cause of XLRS in Chinese people. The detection of gene mutations may provide the guidance of genetic diagnosis and the consultation of family heredity for the patients and their families. (Chin J Ocul Fundus Dis, 2006, 22: 77-81)