Objectives: 

TRPA1 is an ion channel located on the plasma membrane of several human and animal cells. This channel has been identified as a target for the noxious and inflammatory irritants in peripheral sensory neurons, thus, indicating a functional role for this channel in inflammation. The aim of the present study is to investigate the role of this channel in cells of the megakaryoblastic lineage.

Materials: 

MEG01 cells were obtained from ATCC and cultured in RPMI media. Platelets were obtained from blood drawn from healthy volunteers in accordance with the Declaration of Helsinki. Intracellular free Ca2+ concentration ([Ca2+]c) was determined by fluorimetry and protein expression by Real-Time PCR and Western blotting.

Results: 

Despite TRPA1 mRNA has been reported in human platelets, in our hands the protein was undetectable by Western blotting. In contrast, TRPA1 protein was detected in MEG01 cells. Stimulation of TRPA1 with allyl isothiocyanate (AITC) or inhibition using HC-030031 did not generate any Ca2+ signal. Pretreatment of MEG01 cells with AITC or HC-030031 did not alter thrombin-induced Ca2+ release from the intracellular stores; however, TRPA1 inhibition by HC-030031 significantly enhanced thrombin-evoked Ca2+ entry, which involves capacitative Ca2+ entry (CCE) and non-capacitative Ca2+ influx (p<0.05 Student´s t-test; n=6). Pretreatment of MEG01 cells with HC-030031 did not significantly modify thapsigargin-induced CCE; thus suggesting that TRPA1 is not involved in CCE.

Conclusions: 

In conclusion, our results suggest that TRPA1 plays a functional role in thrombin-stimulated MEG01 cells as a regulatory unit of non-capacitative Ca2+ entry.

Supported by MINECO grant BFU2010-21043-C02-01 and Junta de Extremadura-FEDER (GR10010). LA was supported by a MINECO grant BES-2011-043356.