Pathological Angiogenesis Requires Syndecan-4 for Efficient VEGFA-Induced VE-Cadherin Internalization.

Objective: VEGFA (Vascular endothelial growth factor A) and its receptor VEGFR2 (vascular endothelial growth factor receptor 2) drive angiogenesis in several pathologies, including diabetic retinopathy, wet age-related macular degeneration, and cancer. Studies suggest roles for HSPGs (heparan sulfate proteoglycans) in this process, although the nature of this involvement remains elusive. Here, we set to establish the role of the HSPG SDC4 (syndecan-4) in pathological angiogenesis. / Approach and Results: We report that angiogenesis is impaired in mice null for SDC4 in models of neovascular eye disease and tumor development. Our work demonstrates that SDC4 is the only SDC whose gene expression is upregulated during pathological angiogenesis and is selectively enriched on immature vessels in retinas from diabetic retinopathy patients. Combining in vivo and tissue culture models, we identified SDC4 as a downstream mediator of functional angiogenic responses to VEGFA. We found that SDC4 resides at endothelial cell junctions, interacts with vascular endothelial cadherin, and is required for its internalization in response to VEGFA. Finally, we show that pathological angiogenic responses are inhibited in a model of wet age-related macular degeneration by targeting SDC4. / Conclusions: We show that SDC4 is a downstream mediator of VEGFA-induced vascular endothelial cadherin internalization during pathological angiogenesis and a potential target for antiangiogenic therapies

Analysis of EGFR, HER2, and TOP2A gene status and chromosomal polysomy in gastric adenocarcinoma from Chinese patients

<p>Abstract</p> <p>Background</p> <p>The EGFR and HER2 genes are located on chromosomes 7 and 17, respectively. They are therapeutic targets in some tumors. The TOP2A gene, which is located near HER2 on chromosome 17, is the target of many chemotherapeutic agents, and co-amplification of HER2 and TOP2A has been described in several tumor types. Herein, we investigated the gene status of EGFR, HER2, and TOP2A in Chinese gastric carcinoma patients. We determined the rate of polysomy for chromosomes 7 and 17, and we attempted to clarify the relationship between EGFR, HER2, and TOP2A gene copy number and increased expression of their encoded proteins. Furthermore, we tried to address the relationship between alterations in EGFR, HER2, and TOP2A and chromosome polysomy.</p> <p>Methods</p> <p>One hundred cases of formalin fixed and paraffin embedded tumor tissues from Chinese gastric carcinoma patients were investigated by immunohistochemistry and fluorescence in situ hybridization (FISH) methods.</p> <p>Results</p> <p>Forty-two percent of the cases showed EGFR overexpression; 16% showed EGFR FISH positive; 6% showed HER2 overexpression; and 11% showed HER2 gene amplification, including all six HER2 overexpression cases. TOP2A nuclear staining (nuclear index, NI) was determined in all 100 tumors: NI values ranged from 0.5 – 90%. Three percent of the tumors showed TOP2A gene amplification, which were all accompanied by HER2 gene amplification. Nineteen percent of the tumors showed chromosome 7 polysomy, and 16% showed chromosome 17 polysomy. Chromosome 7 polysomy correlated significantly with EGFR FISH-positivity, but was not associated with EGFR overexpression. HER2 overexpression associated significantly with HER2 gene amplification. TOP2A gene amplification was significantly associated with HER2 gene amplification. No relationship was found between alterations in the <it>EGFR</it>, <it>HER2</it>, and <it>TOP2A </it>genes and clinicopathologic variables of gastric carcinoma.</p> <p>Conclusion</p> <p>The data from our study suggest that chromosome 7 polysomy may be responsible for increased EGFR gene copy number in gastric carcinomas, and that HER2 gene amplification may be the major reason for HER2 protein overexpression. A combined investigation of the gene status of EGFR, HER2, and TOP2A should facilitate the identification of a target therapeutic regimen for gastric carcinoma patients.</p

Propriedades mecânicas do músculo gastrocnêmio de ratas, imobilizado e posteriormente submetido a diferentes protocolos de alongamento Mechanical properties of gastrocnemius muscle of female rats immobilized and posteriorly submitted to different stretching protocols

O alongamento é amplamente utilizado na prática clínica da fisioterapia e no desporto, porém, as alterações mecânicas que essa técnica gera no músculo esquelético são pouco exploradas cientificamente. Este estudo avaliou as alterações mecânicas que acometem o músculo gastrocnêmio de ratas Wistar, adultas jovens, após 14 dias de imobilização e, secundariamente, submetido a alongamento manual passivo por 10 dias consecutivos, aplicado uma ou duas vezes ao dia. Foram utilizados 50 animais, sendo 10 para cada grupo: Controle (GC); Imobilizado (GI); Imobilizado e Liberado (GIL); Imobilizado e alongado uma vez ao dia (GIA1); e Imobilizado e alongado duas vezes ao dia (GIA2). O músculo gastrocnêmio foi submetido ao ensaio mecânico de tração, onde foram avaliadas as propriedades de carga e alongamento nos limites máximo e proporcional, além de rigidez e resiliência. A imobilização reduziu os valores das propriedades mecânicas de carga no limite máximo (CLM), carga no limite proporcional (CLP), alongamento no limite máximo (ALM), rigidez e resiliência, em 44,4%, 34,4%, 27,6%, 64,4% e 54%, respectivamente, quando comparados com os valores do GC. A remobilização livre e o alongamento restauraram as propriedades de CLM, CLP, ALM, rigidez e resiliência do músculo, exceto para o GIA2, que foi incapaz de restabelecer a propriedade de ALM (31,3% menor que GC). Concluí-se, portanto que, após 14 dias de imobilização segmentar, cargas individuais de alongamento e a livre movimentação permitem restituir as propriedades mecânicas do tecido muscular.<br>Stretching is widely employed in physiotherapeutic clinical practice and in sportive activities; however, the mechanical alterations of the skeletal muscle generated by this technique are poorly scientifically investigated. This study evaluated the mechanical alterations suffered by the gastrocnemius muscle of young adult female Wistar rats, submitted to14 days of immobilization followed by passive manual stretching during 10 consecutive days once or twice a day. Fifty animals were equally distributed in five groups, Control (CG); Immobilized (IG); Immobilized and liberated (ILG); Immobilized and submitted to stretching once a day (IEG1); Immobilized and submitted to stretching twice a day (IEG2). The gastrocnemius muscle was analyzed by mechanical traction assay and the properties related to load and maximal and proportional stretching evaluated in addition to stiffness and resilience. Immobilization decreased load at maximal thresholds (MTL), load at proportional thresholds (LPT), stretch at maximal thresholds (SMT), stiffness and resilience were reduced in 44.4%, 34.4%, 27.6%, 64.4% and 54% respectively, compared to CG values. With subsequent free remobilization and stretching, all parameters were restored except for IEG2 in which SMT remained reduced in 31.3%, when compared to CG. It is concluded that after 14 days of segmental immobilization, individual stretching loads and free movements contribute to regain muscle mechanical properties