Biomedical subjects

Kaili Wu

Publications and source records attributed to Kaili Wu.

13 recordsLinked to original sources

PubMed2026

Mitochondrial dysfunction in the pathogenesis of intervertebral disc herniation: a mitochondrial related genome-wide Mendelian randomization analysis.

BACKGROUND: As a degenerative disease, the pathophysiology of intervertebral disc herniation (IDH) closely related to mitochondrial dysfunction. However, the specific molecular mechanisms involved have yet to be precisely established. METHODS: Here, we employed a two-sample, two-step Mendelian Randomization (MR) approach, along with summary-Data-Based MR, genetic colocalization, full phenomenon association analysis, and GO and KEGG enrichment analysis to investigate the genetical effects of mitochondrial dysfunction on IDH. RESULTS: From the intercross between mitochondrial-related genes and eQTLGen genes, we obtained seven genes (DMPK, EHHADH, SLC25A16, ME3, METTL17, TUFM, NDUFA13) with strong causal association with disc herniation. By SMR and genetic colocalization analysis, we further identify five key genes (EHHADH, METTL17, TUFM, NDUFA13, DMPK) as the direct causal tartgeted genes with no heterogeneity and pleiotropy in the SNPs of the genes. Full phenomenon Mendelian randomization was performed to determine possible side effects of the 5 targeting genes. Finally, we validated the expressions of key genes in the degenerative intervertebral discs tissues by qRT-PCR and double-immunofluorescence examinations, and the results were consistent with the MR analysis. CONCLUSIONS: Our study provided genetic support for the relationship between mitochondrial related genes and IDH, implicating potential therapeutic targets for future development. However, more basic experiments need to be finished to validate the role of key genes in the development of IDH.

Intervertebral Disc Displacement↗

PubMed2004

The role of cyclin D2 and p21/waf1 in human T-cell leukemia virus type 1 infected cells.

BACKGROUND: The human T-cell leukemia virus type 1 (HTLV-1) Tax protein indirectly influences transcriptional activation, signal transduction, cell cycle control, and apoptosis. The function of Tax primarily relies on protein-protein interactions. We have previously shown that Tax upregulates the cell cycle checkpoint proteins p21/waf1 and cyclin D2. Here we describe the consequences of upregulating these G1/S checkpoint regulators in HTLV-1 infected cells. RESULTS: To further decipher any physical and functional interactions between cyclin D2 and p21/waf1, we used a series of biochemical assays from HTLV-1 infected and uninfected cells. Immunoprecipitations from HTLV-1 infected cells showed p21/waf1 in a stable complex with cyclin D2/cdk4. This complex is active as it phosphorylates the Rb protein in kinase assays. Confocal fluorescent microscopy indicated that p21/waf1 and cyclin D2 colocalize in HTLV-1 infected, but not in uninfected cells. Furthermore, in vitro kinase assays using purified proteins demonstrated that the addition of p21/waf1 to cyclin D2/cdk4 increased the kinase activity of cdk4. CONCLUSION: These data suggest that the p21/cyclin D2/cdk4 complex is not an inhibitory complex and that p21/waf1 could potentially function as an assembly factor for the cyclin D2/cdk4 complex in HTLV-1 infected cells. A by-product of this assembly with cyclin D2/cdk4 is the sequestration of p21/waf1 away from the cyclin E/cdk2 complex, allowing this active cyclin-cdk complex to phosphorylate Rb pocket proteins efficiently and push cells through the G1/S checkpoint. These two distinct functional and physical activities of p21/waf1 suggest that RNA tumor viruses manipulate the G1/S checkpoint by deregulating cyclin and cdk complexes.

3T3 Cells↗

PubMed2003

Protein profile of tax-associated complexes.

Infection with human T-cell leukemia virus type 1 (HTLV-1) results in adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. Tax, a 40-kDa protein, regulates viral and cellular transcription, host signal transduction, the cell cycle, and apoptosis. Tax has been shown to modulate cellular CREB and NFkappaB pathways; however, to date, its role in binding to various host cellular proteins involved in tumorigenesis has not been fully described. In this study, we describe the Tax-associated proteins and their functions in cells using several approaches. Tax eluted from a sizing column mostly at an apparent molecular mass of 1800 kDa. Following Tax immunoprecipitation, washes with high salt buffer, two-dimensional gel separation, and mass spectrometric analysis, a total of 32 proteins was identified. Many of these proteins belong to the signal transduction and cytoskeleton pathways and transcription/chromatin remodeling. A few of these proteins, including TXBP151, have been shown previously to bind to Tax. The interaction of Tax with small GTPase-cytoskeleton proteins, such as ras GAP1m, Rac1, Cdc42, RhoA, and gelsolin, indicates how Tax may regulate migration, invasion, and adhesion in T-cell cancers. Finally, the physical and functional association of Tax with the chromatin remodeling SWI/SNF complex was assessed using in vitro chromatin remodeling assays, chromatin remodeling factor BRG1 mutant cells, and RNA interference experiments. Collectively, Tax is able to bind and regulate many cellular proteins that regulate transcription and cytoskeletal related pathways, which might explain the pleiotropic effects of Tax leading to T-cell transformation and leukemia in HTLV-1-infected patients.

Adult↗

PubMed2003

Paradoxical effects of a stress signal on pro- and anti-apoptotic machinery in HTLV-1 Tax expressing cells.

Adult T-cell leukemia (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) are associated with Human T-cell lymphotropic virus type 1 (HTLV-1) infection. The viral transactivator, Tax is able to mediate the cell cycle progression by targeting key regulators of the cell cycle such as p21/waf1, p16/ink4a, p53, cyclins D1-3/cdk complexes, and the mitotic spindle checkpoint MAD apparatus, thereby deregulating cellular DNA damage and checkpoint control. Genome expression profiling of infected cells exemplified by the development of DNA microarrays represents a major advance in genome-wide functional analysis. Utilizing cDNA microarray analysis, we have observed an apparent opposing and paradoxical regulatory network of host cell gene expression upon the introduction of DNA damage stress signal. We find the apparent induction of cell cycle inhibitors, and pro- as well as anti-apoptotic gene expression is directly linked to whether cells are at either G1, S, or G2/M phases of the cell cycle. Specifically, a G1/S block is induced by p21/waf1 and p16/ink4a, while pro-apoptotic expression at S, and G2/M is associated with caspase activation, and anti-apoptotic gene expression is associated with up regulation of Bcl-2 family member, namely bfl-1 gene. Therefore, the microarray results indicating expression of both pro- and anti-apoptotic genes could easily be explained by the particular stage of the cell cycle. Mechanism and the functional outcome of induction for both pathways are discussed.

Apoptosis↗

PubMed2003

Induction of cortical cataracts in cultured mouse lenses with H-89, an inhibitor of protein kinase A.

PURPOSE: To compare the effects of two serine-threonine protein kinase inhibitors in a mouse lens culture system previously designed to investigate cortical cataracts caused by L-buthionine sulfoximine (BSO), inhibitor of GSH biosynthesis. METHODS: Cataract development in HL-1 medium was evaluated visually or by measurement of lens Na+/K+ ratio through atomic absorption. Protein changes were evaluated by 32P-labeling, 2D-gel electrophoresis, phosphorimaging and mass spectrometry. Results. H-7 (50 microM), inhibitor of protein kinase A (PKA) and protein kinase C (PKC), did not cause cataracts, but inhibited BSO cataract development. By contrast, 25 microM H-89, selective inhibitor of PKA, caused large annular cortical cataracts and 100-fold elevation of Na+/K+ within 30 hr in day 10 lenses, in either the presence or absence of BSO. H-89 cataracts were also seen in day 12 and day 21 lenses. 32P-labeling of day 12 lenses pretreated with H-89 displayed more than 80% decrease in phosphorylation of alphaA crystallin, a known substrate of PKA, in the insoluble protein fraction. 2D-gel electrophoresis of day 12 H-89 cataract lens fractions revealed limited degradation of alpha and beta crystallins, degradation of cytoskeletal proteins, and elevated lens Ca2+ (>4 nmol/mg wet wt.), suggesting Ca2+-activated proteolysis. Conclusions. High Na+/K+ cataracts are induced by H-89, selective inhibitor of PKA, but not by H-7, an inhibitor of both PKA and PKC that impeded BSO-induced Na+/K+ elevation and cataract. These results suggest contrasting effects of PKA and PKC on lens cation transport and cortical cataract development.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2003

[Proteomics in ophthalmology].

Proteomics is the study of total expressed proteins of genome in certain cell, tissue or organ. It is the frontier of the research in life science in the new century, and the core of functional genomics. Proteomics provides a new way to study ocular cell behaviors and the mechanisms of ocular disease. Here we reviewed the applications of proteomics in ophthalmology.

Electrophoresis, Gel, Two-Dimensional↗

PubMed2002

Gene expression profile of HIV-1 Tat expressing cells: a close interplay between proliferative and differentiation signals.

BACKGROUND: Expression profiling holds great promise for rapid host genome functional analysis. It is plausible that host expression profiling in an infection could serve as a universal phenotype in virally infected cells. Here, we describe the effect of one of the most critical viral activators, Tat, in HIV-1 infected and Tat expressing cells. We utilized microarray analysis from uninfected, latently HIV-1 infected cells, as well as cells that express Tat, to decipher some of the cellular changes associated with this viral activator. RESULTS: Utilizing uninfected, HIV-1 latently infected cells, and Tat expressing cells, we observed that most of the cellular host genes in Tat expressing cells were down-regulated. The down-regulation in Tat expressing cells is most apparent on cellular receptors that have intrinsic receptor tyrosine kinase (RTK) activity and signal transduction members that mediate RTK function, including Ras-Raf-MEK pathway. Co-activators of transcription, such as p300/CBP and SRC-1, which mediate gene expression related to hormone receptor genes, were also found to be down-regulated. Down-regulation of receptors may allow latent HIV-1 infected cells to either hide from the immune system or avoid extracellular differentiation signals. Some of the genes that were up-regulated included co-receptors for HIV-1 entry, translation machinery, and cell cycle regulatory proteins. CONCLUSIONS: We have demonstrated, through a microarray approach, that HIV-1 Tat is able to regulate many cellular genes that are involved in cell signaling, translation and ultimately control the host proliferative and differentiation signals.

Cell Cycle↗

PubMed2002

Inhibition of HTLV-1 transcription by cyclin dependent kinase inhibitors.

HTLV-1 is the etiologic agent for adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), where viral replication and transformation are largely dependent upon modification of regulatory and host cell cycle proteins. The mechanism of HTLV-1 transformation appears to be distinct from that of many known chronic or acute leukemia viruses and is related to the viral activator Tax. Here we show that cyclin E, can associate tightly with the coactivator p300 and Pol II complex in HTLV-1 infected cells. The cyclin E associated complex is kinase active and phosphorylates the carboxy terminal domain of RNA Pol II. More importantly, p21/Waf1, a well-known cdk inhibitor at the G1/S border, inhibits transcription of HTLV-1 in both transfections and in in vitro transcription assays. Finally, specific cdk chemical inhibitors, functionally similar to cellular cdkIs, such as p21/Waf1 which inhibits cyclin E/cdk2 activity, also inhibit transcription of the HTLV-1 promoter. In particular, Purvalanol A, with an IC50 of 0.035 microm inhibits activated, but not basal transcription, as well as HTLV-1 infected cells. Collectively, the role of cyclin E/cdk2 in HTLV-1 infected cells and its involvement in RNA Pol II phosphorylation is discussed.

Amino Acid Sequence↗

PubMed2002

Altered patterns of phosphorylation in cultured mouse lenses during development of buthionine sulfoximine cataracts.

Buthionine sulfoximine (BSO), a specific inhibitor of glutathione biosynthesis, induces oxidative cataracts following multiple injections into mice at 1 week of age. Cultures of lenses with (35)S-methionine have previously demonstrated altered patterns of protein biosynthesis that precede and accompany these cataracts. To obtain parallel information about changes in protein phosphorylation during cataract development, lenses from BSO-treated or control mouse pups were cultured for 3 hr at 37 degrees C with (32)P(i), homogenized in phosphate buffer, and resolved by centrifugation into water-soluble (WS) and water-insoluble (WI) fractions. These were characterized by 2D-gel electrophoresis, Coomassie blue staining, phosphorimaging, immunoblotting, and tandem mass spectrometry. Heaviest labelling was in the WI fraction. The labelled 2D-gel spots included: (1) a series of phosphorylated filensins at 95 kDa; (2) a major radioactive spot at 45-50 kDa, slightly anodic to actin and the beaded filament protein, phakinin (CP 49); (3) a phosphorylated betaB1-crystallin, considerably anodic to parent betaB1; (4) an acidic cluster of labelled alphaA-crystallins, phosphorylated in part at serine-148, and (5) a labelled trace alpha crystallin, slightly anodic to alphaB-crystallin. The results confirm previously reported phosphorylations of actin, phakinin, alphaA- and alphaB-crystallin, demonstrate previously unrecognized phosphorylations of filensin and betaB1-crystallin, and provide unequivocal evidence for phosphorylation of alphaA-crystallin at serine-148. The earliest changes in phosphorylation detected after BSO treatment were increased labelling of alphaA- and alphaB-crystallin during cataract stages 1-3, coupled with a general decrease in protein labelling. In stage 5 cataracts, phosphorylated alpha crystallins persisted as the dominant labelled species. However, the major modifications of alphaA-crystallin in advanced BSO cataracts were unlabelled and partially degraded, in contrast to phosphorylated alphaA. It is therefore proposed that phosphorylation of alphaA-crystallin may confer resistance to proteolytic degradation.

Animals↗

PubMed2002

[Quality of life assessment of cataract surgery in elderly population of Doumen County, Guangzhou Province].

OBJECTIVE: To evaluate the outcome of cataract surgery in elderly population in Doumen County, Guangdong Province by assessment of subjective visual function and quality of life. METHODS: All the cataract postoperative subjects were identified in the population-level. Visual Function and Quality of Life (VF/QOL) questionnaire developed by National Eye Institute, USA in developing countries was used as the instrument. This Questionnaire was administered by four trained-interviewers in all subjects with visual acuity less than 0.1 in either eye (treated as visual impairment cases), One in every 20 persons with visual acuity better than 0.3 (treated as normal control cases) in both eyes (un-operated group) and all cataract postoperative cases (operated group). RESULTS: In 5 342 cross-sectional examined persons, individuals who could be successfully interviewed included 99 (90.8%) cataract postoperative cases, 535 (85.5%) visual impairment cases and 119 normal control ones. On a 0 - 100 scale, medium total scores of VF and QOL diminished from 92 to 2 and from 100 to 19 respectively along with visual status from normal to severe blindness in the un-operated group. Similar findings on visual status and VF/QOL scores were found in the operated group. The overall scores of VF and QOL were 40 and 56 for operated one and 56 and 72 for un-operated one. After adjusted the confounding effect of visual status, age, sex and education by multivariate regression model, the difference of QOL scores between un-operated and operated group was significant (P = 0.015), while no significant difference (P = 0.199) was found in VF scores. CONCLUSIONS: The scores of VF and QOL are significantly correlated with the visual status. Subjective visual function and quality of life could not be significantly improved after cataract surgery in this target population. Concerns should be paid in postoperative follow-up, aphakic correction and social-psychological rehabilitation.

Aged↗

PubMed2002

Pterygium in aged population in Doumen County, China.

PURPOSE: To estimate the prevalence of pterygium and its influence on visual acuity in aged population of Doumen County, southern China. METHODS: A population-based survey was conducted in Doumen County, the rural area of southern China. Twenty-seven sample units were selected by random sampling. The prevalence and severity of pterygium and it-related low visual acuity were analyzed. RESULTS: Of the total 4 762 individuals aged 50 years or over, 4 214 were examined. The prevalence of pterygium was 33.01% in subjects aged 50 years or above. There was a significantly higher prevalence in female (35.70%) than in male (29.70%, P = 0.025). The prevalence of pterygium in age groups of 50s, 60s, 70s and 80s years old is 33.98%, 36.40%, 30.73% and 25.40%, respectively. Most of the pterygia were located in the nasal side (93.31%) of cornea, and only 6.69% in the temporal side. 0.92% of the eyes had visual acuity less than 0.32, which were directly caused by pterygia. CONCLUSION: The current survey suggests that the pterygium is one of the most common diseases of external eye in the population aged 50 years and above. It is still leading to the impairment of visual acuity in the rural area.

Aged↗

PubMed2001

Enhancement of nuclear factor-kappa B acetylation by coactivator p300 and HIV-1 Tat proteins.

Nuclear factor (NF)-kappaB transcription factors are involved in the control of a large number of normal cellular and organismal processes, such as immune and inflammatory responses, developmental processes, cellular growth, and apoptosis. Transcription of the human immunodeficiency virus type 1 (HIV-1) genome depends on the intracellular environment where the integrate viral DNA is regulated by a complex interplay among viral regulatory proteins, such as Tat, and host cellular transcription factors, such as NF-kappaB, interacting with the viral long terminal repeat region. CBP (CREB-binding protein) and p300, containing an intrinsic histone acetyltransferase (HAT) activity, have emerged as coactivators for various DNA-binding transcription factors. Here, we show that the p50 subunit as well as the p50/p65 of NF-kappaB, and not other factors such as SP1, TFIIB, polymerase II, TFIIA, or p65, can be acetylated by CBP/p300 HAT domain. Acetylation of p50 was completely dependent on the presence of both HAT domain and Tat proteins, implying that Tat influences the transcription machinery by aiding CBP/p300 to acquire new partners and increase its functional repertoire. Three lysines, Lys-431, Lys-440, and Lys-441 in p50 were all acetylated in vitro, and a sequence similarity among p50, p53, Tat, and activin receptor type I on these particular lysines was observed. All proteins have been shown to be acetylated by the CBP/p300 HAT domain. Acetylated p50 increases its DNA binding properties, as evident by streptavidin/biotin pull-down assays when using labeled NF-kappaB oligonucleotides. Increased DNA binding on HIV-1 long terminal repeat coincided with increases in the rate of transcription. Therefore, we propose that acetylation of the DNA binding domain of NF-kappaB aids in nuclear translocation and enhanced transcription and also suggest that the substrate specificity of CBP/p300 can be altered by small peptide molecules, such as HIV-encoded Tat.

Acetylation↗

PubMedDate not supplied

Ultraviolet B-induced corneal and lens damage in guinea pigs on low-ascorbic acid diet.

To evaluate ocular morphological response to ultraviolet B (UV-B) exposure in guinea pigs fed with normal and low-ascorbic acid (ASA) diets, 24 guinea pigs were randomly divided into UVR (normal diet + UV-B), LVC (low-ASA diet + UV-B) and CTL (normal diet, without UV-B) groups. The irradiated animals were exposed to 8.2 J/cm(2) of UV-B over 29 weeks. Changes in the cornea and lens were examined using a Scheimpflug camera, specular microscope and histological studies. ASA contents in the plasma, aqueous humor and lens sections were measured by high-performance liquid chromatography. The results showed low contents of ASA in the plasma, aqueous humor and lens sections in LVC. Both irradiated groups displayed corneal epithelial edema, neovascularization in stroma, increase in corneal thickness, decrease in endothelial density, and lens epithelial damage. No significant morphological differences in cornea and lens were found between guinea pigs fed with low-ASA or normal diet.

Animals↗