RESUMO
In Drosophila larvae, acquired synaptic thermotolerance after heat shock has previously been shown to correlate with the induction of heat shock proteins (Hsps) including HSP70. We tested the hypothesis that synaptic thermotolerance would be significantly diminished in a temperature-sensitive strain (Drosophila heat shock factor mutant hsf4), which has been reported not to be able to produce inducible Hsps in response to heat shock. Contrary to our hypothesis, considerable thermoprotection was still observed at hsf4 larval synapses after heat shock. To investigate the cause of this thermoprotection, we conducted DNA microarray experiments to identify heat-induced transcript changes in these organisms. Transcripts of the hsp83, dnaJ-1 (hsp40), and glutathione-S-transferase gstE1 genes were significantly upregulated in hsf4 larvae after heat shock. In addition, increases in the levels of Hsp83 and DnaJ-1 proteins but not in the inducible form of Hsp70 were detected by Western blot analysis. The mode of heat shock administration differentially affected the relative transcript and translational changes for these chaperones. These results indicate that the compensatory upregulation of constitutively expressed Hsps, in the absence of the synthesis of the major inducible Hsp, Hsp70, could still provide substantial thermoprotection to both synapses and the whole organism.
Assuntos
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico/metabolismo , Transmissão Sináptica/fisiologia , Aclimatação , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster/metabolismo , Perfilação da Expressão Gênica/métodos , Proteínas de Choque Térmico HSP40/genética , Fatores de Transcrição de Choque Térmico , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico/genética , Temperatura Alta , Larva/genética , Larva/metabolismo , Mutação , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação para CimaRESUMO
This randomized double blind AB/BA cross-over trial evaluates the effect of oral modafinil versus placebo on spasticity, function, and quality of life in children with cerebral palsy (CP). Outcomes were measured at the start and end of both 8-week treatment periods (modafinil and placebo). The order of the treatment periods was randomly assigned. There was a 4-week wash-out period between treatments. Primary outcomes include the Modified Ashworth Score (MAS), and the Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD), a disorder-specific quality of life measure. Ten children were randomized and eight children completed the study. The mean age of participants was 11 years 5 months (SD 1 y 5 mo, range 8 y 8 mo-12 y 11 mo). Five of the participants were male and three female. Seven children had a diagnosis of spastic quadriplegic CP and one child had spastic diplegia with overflow tone to the upper extremities. The Gross Motor Function Classification System ranged from Level III to V with one child at Level III, six children at Level IV, and one at Level V. The CPCHILD pre- to post-total scores showed a slight improvement in quality of life during the placebo period and a slight deterioration in the modafinil period (overall mean change of 7.1, SD 7.6). A t-test between post differences was statistically significant (t=2.65, p=0.03) in favor of the placebo period. The MAS for elbow flexors, ankle flexors, and hip adductors did not show any significant reduction post-modafinil or post-placebo (p values ranged from 0.41-0.79). This study did not find evidence that modafinil reduces spasticity or has a positive impact on quality of life in children with spastic CP.