Biomedical subjects

Shiming Chen

Publications and source records attributed to Shiming Chen.

At least 19 recordsLinked to original sources

PubMed2026

Decoupled Synthesis Pathway via Precursor Functionalization Stabilizes High-Voltage Nickel-Based Cathodes.

Nickel-based layered cathodes are promising candidates for high-performance, high-energy lithium-ion batteries, yet their high-voltage application is jointly limited by synthesis-inherited structural defects and an unstable lattice oxygen framework. Here, we show that both limitations can be overcome by decoupled synthesis pathway (DSP) via La/Nb oxalate functionalization of the Ni0.6Co0.1Mn0.3(OH)2 precursor. Unlike the conventional coupled synthesis pathway (CSP) where precursor dehydration and Li2CO3 decomposition overlap in temperature, the DSP introduces a low‑temperature decomposition of La/Nb oxalates at 200°C, which effectively avoids localized contact between the precursor and Li2CO3 and shifts Li2CO3-related reactions to high temperatures. This allows sequential precursor dehydroxylation, rock‑salt (RS) intermediate formation, and layered‑phase transformation over a broad temperature window. The resulting LiNi0.6Co0.1Mn0.3O2 cathode with La/Nb functionalization (NCM-LN) features a uniform surface LaNiO3 perovskite heterostructure and a Nb‑doped layered bulk with suppressed RS and spinel defects. Consequently, under 4.5 V operation (vs. Li+/Li), NCM-LN exhibits homogeneous Li+ (de)intercalation, and a stabilized oxygen framework. In graphite||NCM-LN full cells, NCM-LN retains 80.1% of its capacity after 2000 cycles at 1C, substantially outperforming the pristine cathode. This decoupling strategy is broadly effective across various Ni‑based systems, providing a generalizable route toward high‑energy, long‑life cathode materials.

decoupled synthesis pathway↗

PubMed2006

[The effects on expressions of p53 and PCNA by inhibition of hTERT with siRNA in transplantable model of human laryngeal squamous carcinoma in nude mice].

OBJECTIVE: To investigate the expressions of p53 and PCNA by inhibition of hTERT with siRNA in xenografted laryngeal squamous carcinoma in nude mice. METHOD: pshRNA involved fluorescein gene was synthesized according to the sequence of hTERT cDNA. The xenografted tumor in nude mice was established by using human laryngeal squamous carcinoma cell line (Hep-2). pshRNA packaged by METAFECTENE was transfected into the transplantation tumors. The volumes of the subcutaneous tumor were determined. Fluorescence expression in the tumors was detected by confocal microscopy. The expressions of p53 and PCNA were detected using immunohistochemistry. RESULT: The subcutaneous tumors appeared in all the nude mice after transplantation five days later. The diameter of subcutaneous tumors become 5-7 mm after transplantation. Many green fluorescent cells were observed by confocal microscopy after transfection of pshRNA and blank plasmid. The growth of laryngeal squamous carcinoma in nude mice was significantly decreased as compared with the control group. The proliferation activity was inhibited by 76.50%. The expressions of p53 was upregulated and the expression of PCNA was downregulated. CONCLUSION: The transfection of pshRNA could significantly induce inhibitory effects on growth of laryngeal squamous carcinoma in nude mice and the expression of PCNA could be effectively downregulated. The inhibition of telomerase reverse transcriptase (hTERT) mRNA could upregulate the expression of p53 and promote the apoptosis of carcinoma cells as well as inhibit the proliferation of laryngeal squamous carcinoma cells.

Animals↗

PubMed2005

CHX10 targets a subset of photoreceptor genes.

The homeobox gene CHX10 is required for retinal progenitor cell proliferation early in retinogenesis and subsequently for bipolar neuron differentiation. To clarify the molecular mechanisms employed by CHX10 we sought to identify its target genes. In a yeast one-hybrid assay Chx10 interacted with the Ret1 site of the photoreceptor-specific gene Rhodopsin. Gel shift assays using in vitro translated protein confirmed that CHX10 binds to Ret1, but not to the similar Rhodopsin sites Ret4 and BAT-1. Using retinal nuclear lysates, we observed interactions between Chx10 and additional photoreceptor-specific elements including the PCE-1 (Rod arrestin/S-antigen) and the Cone opsin locus control region (Red/green cone opsin). However, chromatin immunoprecipitation assays revealed that in vivo, Chx10 bound sites upstream of the Rod arrestin and Interphotoreceptor retinoid-binding protein genes but not Rhodopsin or Cone opsin. Thus, in a chromatin context, Chx10 associates with a specific subset of elements that it binds with comparable apparent affinity in vitro. Our data suggest that CHX10 may target these motifs to inhibit rod photoreceptor gene expression in bipolar cells.

Animals↗

PubMed2005

Polyglutamine-expanded ataxin-7 inhibits STAGA histone acetyltransferase activity to produce retinal degeneration.

Spinocerebellar ataxia type 7 (SCA7) is characterized by cone-rod dystrophy retinal degeneration and is caused by a polyglutamine [poly(Q)] expansion within ataxin-7, a protein of previously unknown function. Here, we report that ataxin-7 is an integral component of the mammalian STAGA (SPT3-TAF9-ADA-GCN5 acetyltransferase) transcription coactivator complex, interacts directly with the GCN5 histone acetyltransferase component of STAGA, and mediates a direct interaction of STAGA with the CRX (cone-rod homeobox) transactivator of photoreceptor genes. Consistent with these results, chromatin immunoprecipitation assays document retinal-specific association of CRX, GCN5, and acetylated histone H3 with CRX target genes. RNA interference studies also implicate ataxin-7 and GCN5 in CRX-dependent gene activation, and histone deacetylase inhibitors restore the compromised expression of a CRX target gene in an ataxin-7-deficient background. Significantly, in relation to SCA7, poly(Q)-expanded ataxin-7 gets incorporated into STAGA and, in a dominant-negative manner, inhibits the nucleosomal histone acetylation function of STAGA GCN5 both in vitro and, based on chromatin immunoprecipitation assays, in SCA7 transgenic mice. These results suggest that the normal function of a poly(Q) disease protein may intersect with its pathogenic mechanism, an observation with significant implications for the molecular basis of all poly(Q) disorders and ultimately for their treatment.

Acetyltransferases↗

PubMed2005

Sp4 is expressed in retinal neurons, activates transcription of photoreceptor-specific genes, and synergizes with Crx.

To investigate the molecular mechanisms of photoreceptor-specific gene transcription, we examined the role of the neuronal-enriched Sp4 nuclear protein in transcription from the rod-specific beta-PDE and rod opsin gene promoters and compared it to the ubiquitous members of the Sp family, Sp1 and Sp3. Sp4 activates both the rod opsin and beta-PDE promoters, whereas Sp1 activates only the rod opsin promoter and Sp3 activates neither promoter. Interestingly, Sp1 and Sp3 competitively repress Sp4-mediated activation of the beta-PDE promoter. In addition, Sp4, Sp1, and Sp3 each show functional synergy with the photoreceptor-enriched Crx transcriptional regulator on the rod opsin promoter but not the beta-PDE promoter, although Sp4-mediated activation was the most significant. Sp4, Sp1, and Sp3 bind Crx in co-immunoprecipitation experiments, and their zinc finger domains as well as the Crx homedomain are necessary and sufficient for these interactions. Chromatin immunoprecipitation showed that the rod opsin and beta-PDE promoters are targets of both Sp4 and Crx, which further supports Sp4-Crx interactions in vivo in the context of retinal chromatin environment. In situ hybridization and immunohistochemistry demonstrated that Sp4 is abundantly expressed in various neurons of all retinal layers, and thus co-localizes or overlaps with multiple retina-restricted and -enriched genes, its putative targets. Our results indicate that photoreceptor-specific gene transcription is controlled by the combinatorial action of Sp4 and Crx. The other Sp family members may be involved in photoreceptor-specific transcription directly or through their competition with Sp4. These data suggest the potential importance of Sp4 in retinal neurobiology and pathology.

Animals↗

PubMed2005

The photoreceptor-specific nuclear receptor Nr2e3 interacts with Crx and exerts opposing effects on the transcription of rod versus cone genes.

Nr2e3 is an orphan nuclear receptor expressed specifically by retinal photoreceptor cells. Mutations in Nr2e3 result in syndromes characterized by excess blue cones and loss of rods: enhanced S-cone syndrome (ESCS) in humans and rd7 in mice. Using yeast two-hybrid screens with Nr2e3 as bait, the cone-rod homeobox protein Crx was identified as an interacting partner of Nr2e3. Immunoprecipitation assays confirmed this Nr2e3-Crx interaction and identified the DNA-binding domain of each protein as the interaction motif. Immunohistochemistry demonstrated that Crx and Nr2e3 are co-expressed by rod photoreceptors and their precursors. Chromatin immunoprecipitation assays on mouse retina demonstrated that Nr2e3 and Crx co-occupy the promoter/enhancer region of several rod and cone genes in the rod photoreceptor cells. The promoter/enhancer occupancy of Nr2e3 is Crx-dependent, suggesting that Nr2e3 is associated with photoreceptor gene targets by interacting with Crx. Transient transfection assays in HEK293 cells demonstrated that Nr2e3 enhances rhodopsin, but represses S- or M-cone opsin transcription when interacting with Crx. Quantitative real-time RT-PCR analysis on postnatal day 28 (P28) retina of the rd7 mouse, which lacks Nr2e3 protein, revealed an up-regulation of cone genes, but down-regulation of rod genes. Several mutant forms of human Nr2e3 identified from ESCS patients showed defects in interacting with Crx and/or in transcriptional regulatory function. Altogether, our findings suggest that Nr2e3 is a dual-function transcriptional regulator that acts in concert with Crx to promote and maintain the function of rod photoreceptors.

Amino Acid Motifs↗

PubMed2005

Study of the miscibility and segmental motion of STMAA-PBMA polymer blends and semi-interpenetrating polymer networks by an ESR spin probe method.

Linear polymer blends and semi-interpenetrating polymer networks (IPNs) with controlled hydrogen bonding interactions based on poly(styrene-co-methacrylic acid) (STMAA) and poly(butyl methacrylate) (PBMA) were studied by an ESR spin probe method. The observed composite ESR spectra with fast- and slow-motion components in all the samples were ascribed to two-phase morphology. For linear blends, the temperatures T(a) corresponding to appearance of the fast motion, T(d) corresponding to the disappearance of slow motion, T(5mT) and the rotational correlation times tau(c) increased with increasing carboxylic acid content in STMAA. It was concluded that the degree of mixing of the blends was improved with increasing carboxylic acid content, owing to the enhanced hydrogen bonding interactions between the carboxylic acids in STMAA and the ester groups in PBMA. With respect to semi-IPN samples, there existed a competition in the microphase structure between the intercomponent hydrogen bonding interactions, which improved the miscibility of the samples and the intracomponent cross-linking, which might lead to phase separation in the systems with strong specific interactions. When the semi-IPN contained 29 mol% carboxylic acid, the temperatures T(d), T(5mT) and tau(c) reached their minimum values, which indicated that the sample reached its maximum miscibility.

Journal Article↗

PubMed2005

ESR spin-label study of poly(styrene-co-methacrylic acid)/poly(epsilon-caprolactone) semi-interpenetrating polymer networks with controlled hydrogen-bond interactions.

The morphology and miscibility of semi-interpenetrating polymer networks (semi-IPN) prepared with poly(styrene-co-methacrylic acid) [P(S-co-MAA)] of different carboxylic acid contents and poly(epsilon-caprolactone) (PCL) have been studied by ESR spin-label method. The ESR spectra of spin-labeled PCL showed one motional component at any specific temperature. It indicated that the spin-labeled molecules were located in one type of environment. The coexistence of two motional components in the ESR spectra of all semi-IPN samples was observed over a certain temperature range. This phenomenon suggested that the semi-IPNs were not compatible systems; they contained two microphases, a PCL-rich microdomain and a P(S-co-MAA)-rich microdomain. The miscibility could be improved by increasing the carboxylic acid content, which could enhance the hydrogen-bonding interactions between the ester groups of PCL and carboxylic acid groups in P(S-co-MAA). It was also found that the intracomponent cross-linking of the semi-IPNs was not in favor of the miscibility. The microphase separation occurred in all semi-IPNs, even in the samples having strong hydrogen-bonding interactions. With increasing cross-linking density, the microphase separation became more remarkable.

Electron Spin Resonance Spectroscopy↗

PubMed2005

Targeted therapy of human laryngeal squamous cell carcinoma in vitro by antisense oligonucleotides directed against telomerase reverse transcriptase mRNA.

A number of different approaches have been developed to inhibit telomerase activity in human cancer cells. In this study, the effect of antisense oligonucleotides (ODNs) by targeting human telomerase reverse transcriptase (hTERT) mRNA in a laryngeal cancer cell line (Hep-2) was investigated. A 20mer antisense oligodeoxynucleotide targeting the most open part of hTERT mRNA (anti-hTERT) and a mismatched control sequence were synthesized. Cells were treated daily with oligonucleotides for up to 72 hours. hTERT mRNA expression was measured by the reverse transcription polymerase chain reaction (RT-PCR) assay; telomerase activity by the telomerase PCR ELISA assay kit (TRAP; Boehringer Mannheim, GmbH, Mannheim, Germany). Cell viability after administration of ODNs was determined using the MTT assay. Morphological changes were examined by haematoxylin and eosin staining. The cell cycle was analyzed using flow cytometry. It was found that antisense treatment induced a decrease in hTERT mRNA expression, telomerase activity, cell growth rate, cell viability, and an increase in apoptosis. The results suggest that inhibition of telomerase activity in Hep-2 cells by short-term antisense treatment against the mRNA of hTERT results in apoptotic cell death. The treatment with anti-hTERT may be useful as a treatment modality for laryngeal squamous carcinoma.

Apoptosis↗

PubMed2005

[The photodynamic therapy effect of a new cationic porphyrin on human laryngeal cancer Hep-2 cell in vitro].

OBJECTIVE: To investigate the photodynamic therapy (PDT) effect of a new kind of cationic porphyrin on human laryngeal cancer Hep-2 cell in vitro. METHOD: A new cationic porphyrin (5-(4-methoxycarbonylphenyl)-10, 15, 20-tris(4-N-methylpyridiniumyl)porphyrin triiodide ) was synthesized. The Hep-2 cells were treated with three different concentrations of porphyrin (10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L) followed by irradiation of different visible light (0, 0.5, 1.0, 1.5, 2.0 h). MTT and TUNEL were applied to measure the inhibitory effect of porphyrin on the Hep-2 cells growth, inhibitory rate and induced apoptosis rate. RESULT: Under definite condition, the cantionic porphyrin concentrations had a significant inhibitory effect and induced apoptosis effect. The effect depended greatly on the doses of the concentration and the time of irradiation of light. At the highest concentration of porphyrin (10(-5) mol/L), the growth inhibitory rate were 1.18%, 35.21%, 58.59%, 70.42%, 84.34% respectively and the apoptosis rate were 3.30% +/- 0.29%, 29.41% +/- 2.12%, 32.30% +/- 2.26%, 34.52% +/- 3.11% in different visible light (0.05, 1.0, 1.5, 2.0 h), respectively. Under high irradiation energy, it can causesome Hep-2 cells death directly. CONCLUSION: Porphyrin has a distinctive killing effect on Hep-2 cells and correlated with the doses and the irradiation time.

Apoptosis↗

PubMed2005

[Nuclear factor kappaB/p65 and cyclooxygenase-2 expression and clinic significance in human laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate nuclear factor-kappaB/p65(NF-kappaB/p65) and cyclooxygenase-2 (COX-2) gene expressions and clinical significance in human laryngeal squamous cell carcinoma, at the same time to investigate the relationship between the two gene expressions. METHOD: Forty-one samples of laryngeal squamous cell carcinoma and ten samples of vocal cord polyps were assayed using immunohistochemical SP method for detection of NF-kappaB/p65 and COX-2 protein expression level. RESULT: There is significant difference between the laryngeal carcinoma group and vocal cord polyps group about NF-kappaB/p65 and COX-2 protein expression level. Qualitative analysis found theres significant relationship between COX-2 and histological classification. There's significant correlation relationship between NF-kappaB/p65 and COX-2 by using spearman correlation analysis. CONCLUSION: (1)The expressions of NF-kappaB/p65 and COX-2 both raise in laryngeal carcinoma. (2) NF-kappaB/p65 perhaps promotes the expression of COX-2 in laryngeal carcinoma. (3) NF-kappaB was hoped to become the new treated target of laryngeal carcinoma.

Adult↗

PubMed2005

[Influence of RNA interference targeting against human telomerase reverse transcriptase on expression of C-myc protein].

OBJECTIVE: To investigate the effect of inhibiting human telomerase reverse transcriptase (hTERT) on expression of C-myc protein by RNA interference (RNAi) in the larynx cancer cell line, Hep-2. METHOD: The primary structures of hTERT cDNA were found in GeneBank. Then the structure analyses were done according to the strategy of RNAi, which determined the specific base sequences to design shRNA plasmid. One type of plasmid, pshRNA1, involved in fluorescein gene was synthesized based on the specific base sequence. Control pshRNA2-a random sequence-were also constructed. METAFECTENE was used as the transfect ion reagent. Cells were treated daily with pshRNA1-2 or normal culture medium respectively. After administration of pshRNA1-2, hTERT mRNA was detected by RT-PCR, hTERT protein and C-myc protein were examined by Western Blot. RESULT: The expression of hTERT mRNA and protein were both significantly decreased after treated by pshRNA1 (P < 0.05). The expression of C-myc protein was significantly increased after treated by pshRNA1 (P < 0.01). CONCLUSION: The inhibition of hTERT expression could increase the expression of C-myc protein in Hep-2 cells.

Cell Line, Tumor↗

PubMed2004

Cytokine-induced activation of signal transducer and activator of transcription in photoreceptor precursors regulates rod differentiation in the developing mouse retina.

Ciliary neurotrophic factor (CNTF) exhibits multiple biological effects during vertebrate retinogenesis, including regulation of photoreceptor cell differentiation. In the early postnatal mouse retina, CNTF induces rapid and transient phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT3 and the extracellular signal-regulated kinase (ERK). Although both proliferating progenitor cells and postmitotic neurons respond directly to cytokine signals, CNTF elicits distinct phosphorylation patterns of STAT3 and ERK. CNTF stimulation induces low levels of STAT3 phosphorylation in progenitors and differentiated neurons but a robust STAT3 activation among postmitotic photoreceptor precursors expressing the cone-rod homeobox gene Crx and newly differentiated rod photoreceptors. In contrast, CNTF causes preferential phosphorylation of ERK in progenitor cells and photoreceptor precursors. Inhibition of the cytokine receptor gp130 using neutralizing antibodies reveals that gp130 is required for both CNTF-induced STAT3 and ERK phosphorylation. Perturbation of STAT signaling by a STAT inhibitor peptide or a dominant-negative STAT3 mutant causes enhanced production of rod photoreceptors in the absence of exogenous cytokines, whereas inhibiting ERK activation by a MEK (mitogen-activated protein kinase kinase)-specific inhibitor has no effect on rod photoreceptor differentiation in vitro. Furthermore, disrupting the function of epidermal growth factor (EGF) receptors, which modulate rod development in vivo, indicates that the EGF family of ligands does not mediate the inhibitory effect of cytokine on rod differentiation. These results demonstrate that cytokine signal transduction is dynamic and heterogeneous in the developing retina, and that endogenous ligand-induced STAT activation in retinal progenitor and/or photoreceptor precursor cells plays an important role in regulating photoreceptor development.

Animals↗

PubMed2004

QRX, a novel homeobox gene, modulates photoreceptor gene expression.

A novel paired-like homeobox gene, designated as Qrx, was identified by a yeast one-hybrid screen using the bovine Rhodopsin promoter Ret-1 DNA regulatory element as bait. Qrx is preferentially expressed in both the outer and inner nuclear layers of the retina. Its homeodomain is nearly identical to that of Rx/Rax, a transcription factor that is essential for eye development, but it shares only limited homology elsewhere. Although Qrx and Rx/Rax show similar DNA binding properties in vitro, the two proteins demonstrate distinct target selectivity and functional behavior in promoter activity assays. QRX synergistically increases the transactivating function of the photoreceptor transcription factors Crx and NRL and it physically interacts with CRX. Qrx is present in the bovine and human genomes, but appears to be absent from the mouse genome. Nonetheless, a 5.8 kb upstream region of human QRX is capable of directing expression in presumptive photoreceptor precursor cells in transgenic mice. These results indicate that Qrx may be involved in modulating photoreceptor gene expression. In addition, the finding of rare heterozygous QRX sequence changes in three individuals with retinal degeneration raises the possibility that QRX may be involved in disease pathogenesis.

Amino Acid Sequence↗

PubMed2004

Functional analysis of the rod photoreceptor cGMP phosphodiesterase alpha-subunit gene promoter: Nrl and Crx are required for full transcriptional activity.

To understand the factors controlling expression of the cGMP phosphodiesterase type 6 (PDE6) genes, we have characterized the promoter of the human PDE6A gene that encodes the catalytic alpha-subunit. In vivo DNase I hypersensitivity assays revealed two sites immediately upstream of the PDE6A core promoter region. Transient transfection assay in Y79 cells of constructs containing varying lengths of the promoter region showed a decrease in promoter activity with increasing length. The most active segment contained a 177-bp upstream sequence including apparent Crx and Nrl transcription factor binding sites. Both Crx and Nrl transactivated the PDE6A promoter in HEK293 cells and showed a >100-fold increase when coexpressed. Coexpression of a dominant negative inhibitor of Nrl abolished Nrl transactivation but had no effect on Crx. DNase I footprinting assays identified three potential Crx binding sites within a 55-bp segment beginning 29 bp upstream of the transcription start point. Mutation of two of these sites reduced reporter gene activity by as much as 69%. Gel shifts showed that all three Crx sites required a TAAT sequence for efficient binding. Consistent with a requirement for Crx and Nrl in Pde6a promoter activity, Pde6a mRNA is reduced by 87% in the retina of Crx(-/-) mice and is undetectable in Nrl(-/-) mice at postnatal day 10. These results establish that both Nrl and Crx are required for full transcriptional activity of the PDE6A gene.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed2003

Interference of Crx-dependent transcription by ataxin-7 involves interaction between the glutamine regions and requires the ataxin-7 carboxy-terminal region for nuclear localization.

Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disorder caused by expansion of a polyglutamine tract in the ataxin-7 protein. A unique feature of SCA7 is degeneration of photoreceptor cells in the retina, resulting in cone-rod dystrophy. In an SCA7 transgenic mouse model that we developed, it was found that the cone-rod dystrophy involves altered photoreceptor gene expression due to interference with Crx, a homeodomain transcription factor containing a glutamine-rich region. To determine the basis of the Crx-ataxin-7 interaction, Crx and ataxin-7 truncation and point mutants were generated, and the ability of mutant versions of either protein to co-immunoprecipitate the normal version of the other protein was tested. Thus Crx's ataxin-7 interaction domain was localized to its glutamine-rich region and ataxin-7's Crx binding domain was mapped to its glutamine tract. The importance of each protein's respective glutamine region for a productive interaction was confirmed by performing Crx transactivation assays in HEK293 cells and correlating the extent of Crx transcription interference with the intactness of each protein's glutamine region. It was also established that ataxin-7 must localize to the nucleus to repress Crx transactivation, and the likely nuclear localization signals were mapped to ataxin-7's carboxy-terminal region. Finally, using chromatin immunoprecipitation, it was demonstrated that Crx and ataxin-7 engage in a functionally significant interaction by co-occupying the promoter and enhancer regions of Crx-regulated retinal genes in vivo. The results suggest that one mechanism of SCA7 disease pathogenesis is transcription dysregulation, and that Crx transcription interference is a predominant factor in SCA7 cone-rod dystrophy retinal degeneration.

Animals↗

PubMed2003

SCA7 knockin mice model human SCA7 and reveal gradual accumulation of mutant ataxin-7 in neurons and abnormalities in short-term plasticity.

We targeted 266 CAG repeats (a number that causes infantile-onset disease) into the mouse Sca7 locus to generate an authentic model of spinocerebellar ataxia type 7 (SCA7). These mice reproduced features of infantile SCA7 (ataxia, visual impairments, and premature death) and showed impaired short-term synaptic potentiation; downregulation of photoreceptor-specific genes, despite apparently normal CRX activity, led to shortening of photoreceptor outer segments. Wild-type ataxin-7 was barely detectable, as was mutant ataxin-7 in young animals; with increasing age, however, ataxin-7 staining became more pronounced. Neurons that appeared most vulnerable had relatively high levels of mutant ataxin-7; it is interesting, however, that marked dysfunction occurred in these neurons weeks prior to the appearance of nuclear inclusions. These data demonstrate that glutamine expansion stabilizes mutant ataxin-7, provide an explanation for selective neuronal vulnerability, and show that mutant ataxin-7 impairs posttetanic potentiation (PTP).

Animals↗

PubMed2003

[Targeted therapy of human laryngeal squamous cell carcinoma in vitro with telomerase catalytic subunit mRNA].

OBJECTIVE: To study the effect of antisense oligonucleotide targeted human telomerase catalytic subunit (hTERT) on Hep-2 cell line. METHOD: Cells were treated daily with oligonucleotide (ODN) directed against hTERT, or control ODN-a mismatched sequence or only Lipofectamine. At 24 h, 48 h, 72 h cell viability after administration of ODNs was determined using the MTT assay. At 72 h, the morpholog alteration of the cells was observed by HE stain. At 72 h, telomerase activity was determined. RESULT: After daily transfection ASODN, some Hep-2 cells begin to stop growing up, but not in the mismatched ODN group or Lipofectamine group. Hep-2 cells treated with antisense against hTERT showed a decrease in telomerase activity. CONCLUSION: hTERT antisense ODN can inhibit telomerase activity and the growth of Hep-2 cells in short term.

DNA-Binding Proteins↗