Homocysteine induces hypophosphorylation of intermediate filaments and reorganization of actin cytoskeleton in C6 glioma cells.
In this study, we investigated the actions of high homocysteine (Hcy) levels (100 and 500 microM) on the cytoskeleton of C6 glioma cells. Results showed that the predominant cytoskeletal response was massive formation of actin-containing filopodia at the cell surface that could be related with Cdc42 activation and increased vinculin immunocontent. In cells treated with 100 microM Hcy, folic acid, trolox, and ascorbic acid, totally prevented filopodia formation, while filopodia induced by 500 microM Hcy were prevented by ascorbic acid and attenuated by folic acid and trolox. Moreover, competitive NMDA ionotropic antagonist DL-AP5 totally prevented the formation of filopodia in both 100 and 500 microM Hcy treated cells, while the metabotropic non-selective group I/II antagonist MCPG prevented the effect of 100 microM Hcy but only slightly attenuated the effect induced by of 500 microM Hcy on actin cytoskeleton. The competitive non-NMDA ionotropic antagonist CNQX was not able to prevent the effects of Hcy on the reorganization of actin cytoskeleton in the two concentrations used. Also, Hcy-induced hypophosphorylation of vimentin and glial fibrillary acidic protein (GFAP) and this effect was prevented by DL-AP5, MCPG, and CNQX. In conclusion, our results show that Hcy target the cytoskeleton of C6 cells probably by excitoxicity and/or oxidative stress mechanisms. Therefore, we could propose that the dynamic restructuring of the actin cytoskeleton of glial cells might contribute to the response to the injury provoked by elevated Hcy levels in brain.
Loureiro
Samanta Oliveira
SO
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 anexo, CEP 90035-003, Porto Alegre, RS, Brazil.
Heimfarth
Luana
L
Lacerda
Bruna Arcce
BA
Vidal
Luiza Fedatto
LF
Soska
Angela
A
dos Santos
Natália Gomes
NG
de Souza Wyse
Angela Terezinha
AT
Pessoa-Pureur
Regina
R
D000199:Actins / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D002460:Cell Line; D002839:Chromans / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005492:Folic Acid / Q000494:pharmacology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006710:Homocysteine / Q000494:pharmacology*; D007382:Intermediate Filaments / Q000378:metabolism*; D009457:Neuroglia / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D014746:Vimentin / Q000378:metabolism; D014803:Vitamin B Complex / Q000494:pharmacology
D000199:Actins; D000975:Antioxidants; D002839:Chromans; D018690:Excitatory Amino Acid Agonists; D005904:Glial Fibrillary Acidic Protein; D014746:Vimentin; D006710:Homocysteine; D014803:Vitamin B Complex; D005492:Folic Acid; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid