title: An ultra fast detection method reveals strain-induced Ca(2+) entry via TRPV2 in alveolar type II cells.
abstract: A commonly used technique to investigate strain-induced responses of adherent cells is culturing them on an elastic membrane and globally stretching the membrane. However, it is virtually impossible to acquire microscopic images immediately after the stretch with this method. Using a newly developed technique, we recorded the strain-induced increase of the cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) in rat primary alveolar type II (ATII) cells at an acquisition rate of 30ms and without any temporal delay. We can show that the onset of the mechanically induced rise in [Ca(2+)](c) was very fast (<30 ms), and Ca(2+) entry was immediately abrogated when the stimulus was withdrawn. This points at a direct mechanical activation of an ion channel. RT-PCR revealed high expression of TRPV2 in ATII cells, and silencing TRPV2, as well as blocking TRPV channels with ruthenium red, significantly reduced the strain-induced Ca(2+) response. Moreover, the usually homogenous pattern of the strain-induced [Ca(2+)](c) increase was converted into a point-like response after both treatments. Also interfering with actin/myosin and integrin binding inhibited the strain-induced increase of [Ca(2)](c). We conclude that TRPV2 participates in strain-induced Ca(2+) entry in ATII cells and suggest a direct mechanical activation of the channel that depends on FAs and actin/myosin. Furthermore, our results underline the importance of cell strain systems that allow high temporal resolution.
authors.affiliation: Institute for General Physiology / M-25, University of Ulm, Albert Einstein Allee 11, 89081, Ulm, Germany.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Fois
authors.forename: Oliver
authors.initials: O
authors.lastname: Wittekindt
authors.forename: Xing
authors.initials: X
authors.lastname: Zheng
authors.forename: Erika Tatiana
authors.initials: ET
authors.lastname: Felder
authors.forename: Pika
authors.initials: P
authors.lastname: Miklavc
authors.forename: Manfred
authors.initials: M
authors.lastname: Frick
authors.forename: Paul
authors.initials: P
authors.lastname: Dietl
authors.forename: Edward
authors.initials: E
authors.lastname: Felder
mesh_terms: D000199:Actins / Q000737:chemistry; D000465:Algorithms; D000818:Animals; D001696:Biomechanical Phenomena; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002478:Cells, Cultured; D004548:Elasticity; D004867:Equipment Design; D020868:Gene Silencing; D007477:Ions; D008297:Male; D009218:Myosins / Q000737:chemistry; D011650:Pulmonary Alveoli / Q000378:metabolism* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012430:Ruthenium Red / Q000494:pharmacology; D012828:Silicones / Q000737:chemistry; D013314:Stress, Mechanical; D050916:TRPV Cation Channels / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
chemical_list: D000199:Actins; D007477:Ions; D012828:Silicones; D050916:TRPV Cation Channels; C476722:Trpv2 protein, rat; D012430:Ruthenium Red; D009218:Myosins; D002118:Calcium