ABSTRACT
Hypertension and estrogen deficiency in women have been identified as significant risk factors for cerebrovasculardiseases. Hypertension causes excessive vascular stretch and contributes to the initiation of cellular injury in bloodvessels while estrogen has been demonstrated to exert beneficial protective effects on the vascular system. Although thespecific biological outcomes exerted by either excessive stretch or estrogen exposure are well established, the combinedbiochemical effects of both stimuli remain unclear. Therefore, this study was conducted for quantitative proteomics studyon human cerebral microvascular endothelial cells (HCMECs) subjected to 20% “pathological” cyclic stretch for aperiod of 18 hour in the presence or absence of 17β-estradiol by isobaric Taqs for Relative and Absolute Quantification.The results showed that only some proteins responded to 17β-estradiol (e.g., thioredoxin reductase-1), stretch (e.g., 14-3-3 protein epsilon or acidic leucine-rich nuclear phosphoprotein 32 family member B) and interestingly, some proteinsreturned to control pre-treatment levels when exposed to both (e.g., d-dopachrome decarboxylase, thrombospondin-1). Inaddition, HCMECs that exposed only to estrogen had a very similar proteomic profile (i.e., up-regulation of structural,cellular adhesion and proliferation proteins) as to those exposed to estrogen with 20% stretching for 18 hour, suggestingthat estrogen ablated the detrimental effects by the stretch alone. These findings sheds light on the molecular mechanismsby which the cerebrovascular protective actions of estrogen on HCMEC exposed to pathological levels of cyclic stretchwhich could provide a platform for future research in therapeutic approach.