TRP expression pattern and the functional importance of TRPC3 in primary human T-cells

• Published in: Biochimica et biophysica acta 2011-03, Vol.1813 (3), p.412-423
• Main Authors: Wenning, Anna S., Neblung, Katherina, Strauß, Bettina, Wolfs, Melodie-Jo, Sappok, Anne, Hoth, Markus, Schwarz, Eva C.
• Format: Article
• Language: English
• Subjects: Calcium; Calcium - metabolism; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - metabolism; Cell Proliferation; Cells, Cultured; Down-Regulation; Gene Expression Regulation; Humans; Jurkat Cells; Jurkat T-cell; Lymphocyte Activation; Primary human T-cell; Quantitative RT-PCR; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; siRNA; TRP channel; TRPC Cation Channels - genetics; TRPC Cation Channels - metabolism
• ISSN: 0167-4889; 0006-3002; 1879-2596
• DOI: 10.1016/j.bbamcr.2010.12.022

TRP proteins form ion channels which are activated following receptor stimulation. In T-cell lines, expression data of TRP proteins have been published. However, almost no data about TRP expression is available in primary human T-cells. Using RT-PCR and quantitative RT-PCR, we compare the expression of TRP mRNA in 1) human peripheral blood lymphocytes, which are a mix of mostly mono-nuclear blood lymphocytes but contain other leucocytes, 2) a pure human CD4 + T-helper cell population in the resting (= naïve) and activated (= effector) state, and 3) two commonly used CD4 + Jurkat T-cell lines, E6-1 and parental. To mimic physiological cell stimulation, we analyzed TRP expression in primary human cells in a quantitative way over several days following formation of an immunological synapse through stimulation with antibody-coated beads. The TRP expression profile of primary human T-cells was significantly different from Jurkat T-cells. Among the TRP mRNAs of the TRPC, TRPM, and TRPV family, we found consistent expression of TRPC1, TRPC3, TRPV1, TRPM2, and TRPM7 in primary human CD4 + T-cells of all analyzed blood donors. Among these, TRPC3 and TRPM2 were strongly up-regulated following stimulation, but with different kinetics. We found that TRPC3 modulates Ca 2+-dependent proliferation of primary CD4 + T-cells indicating that TRPC3 may be involved in Ca 2+ homeostasis in T-cells besides the well-established STIM and ORAI proteins which are responsible for store-operated Ca 2+ entry. ► In primary human CD4 + T-cells, TRPC1, C3, V1, M2, and M7 are consistently expressed. ► TRPC3 and TRPM2 are up-regulated after T-cell stimulation but with different kinetics. ► STIM1 down-regulation reduces resting intracellular [Ca 2+]. ► TRPC3 down-regulation reduces calcium-dependent T-cell proliferation.