Abstract
Although activation of outward rectifying Cl- channels is one of the fastest responses of endothelial cells (ECs) to shear stress, little is known about these channels. In this study, we used whole-cell patch clamp recordings to characterize the flow-activated Cl- current in bovine aortic ECs (BAECs). Application of shear stress induced rapid development of a Cl- current that was effectively blocked by the Cl- channel antagonist 5-nitro-2-(3-phenopropylamino)benzoic acid (100 μM). The current initiated at a shear stress as low as 0.3 dyne/cm2, attained its peak within minutes of flow onset, and saturated above 3.5 dynes/cm 2 (∼2.5-3.5-fold increase over pre-flow levels). The Cl - current desensitized slowly in response to sustained flow, and step increases in shear stress elicited increased current only if the shear stress levels were below the 3.5 dynes/cm2 saturation level. Oscillatory flow with a physiological oscillation frequency of 1 Hz, as occurs in disturbed flow zones prone to atherosclerosis, failed to elicit the Cl- current, whereas lower oscillation frequencies led to partial recovery of the current. Nonreversing pulsatile flow, generally considered protective of atherosclerosis, was as effective in eliciting the current as steady flow. Measurements using fluids of different viscosities indicated that the Cl - current is responsive to shear stress rather than shear rate. Blocking the flow-activated Cl- current abolished flow-induced Akt phosphorylation in BAECs, whereas blocking flow-sensitive K+ currents had no effect, suggesting that flow-activated Cl- channels play an important role in regulating EC flow signaling.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 36492-36500 |
| Number of pages | 9 |
| Journal | Journal of Biological Chemistry |
| Volume | 281 |
| Issue number | 48 |
| DOIs | |
| State | Published - Dec 1 2006 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Flow-activated chloride channels in vascular endothelium : Shear stress sensitivity, desensitization dynamics, and physiological implications. / Gautam, Mamta; Shen, Yue; Thirkill, Twanda L.; Douglas, Gordon C; Barakat, Abdul I.
In: Journal of Biological Chemistry, Vol. 281, No. 48, 01.12.2006, p. 36492-36500.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Flow-activated chloride channels in vascular endothelium
T2 - Shear stress sensitivity, desensitization dynamics, and physiological implications
AU - Gautam, Mamta
AU - Shen, Yue
AU - Thirkill, Twanda L.
AU - Douglas, Gordon C
AU - Barakat, Abdul I.
PY - 2006/12/1
Y1 - 2006/12/1
N2 - Although activation of outward rectifying Cl- channels is one of the fastest responses of endothelial cells (ECs) to shear stress, little is known about these channels. In this study, we used whole-cell patch clamp recordings to characterize the flow-activated Cl- current in bovine aortic ECs (BAECs). Application of shear stress induced rapid development of a Cl- current that was effectively blocked by the Cl- channel antagonist 5-nitro-2-(3-phenopropylamino)benzoic acid (100 μM). The current initiated at a shear stress as low as 0.3 dyne/cm2, attained its peak within minutes of flow onset, and saturated above 3.5 dynes/cm 2 (∼2.5-3.5-fold increase over pre-flow levels). The Cl - current desensitized slowly in response to sustained flow, and step increases in shear stress elicited increased current only if the shear stress levels were below the 3.5 dynes/cm2 saturation level. Oscillatory flow with a physiological oscillation frequency of 1 Hz, as occurs in disturbed flow zones prone to atherosclerosis, failed to elicit the Cl- current, whereas lower oscillation frequencies led to partial recovery of the current. Nonreversing pulsatile flow, generally considered protective of atherosclerosis, was as effective in eliciting the current as steady flow. Measurements using fluids of different viscosities indicated that the Cl - current is responsive to shear stress rather than shear rate. Blocking the flow-activated Cl- current abolished flow-induced Akt phosphorylation in BAECs, whereas blocking flow-sensitive K+ currents had no effect, suggesting that flow-activated Cl- channels play an important role in regulating EC flow signaling.
AB - Although activation of outward rectifying Cl- channels is one of the fastest responses of endothelial cells (ECs) to shear stress, little is known about these channels. In this study, we used whole-cell patch clamp recordings to characterize the flow-activated Cl- current in bovine aortic ECs (BAECs). Application of shear stress induced rapid development of a Cl- current that was effectively blocked by the Cl- channel antagonist 5-nitro-2-(3-phenopropylamino)benzoic acid (100 μM). The current initiated at a shear stress as low as 0.3 dyne/cm2, attained its peak within minutes of flow onset, and saturated above 3.5 dynes/cm 2 (∼2.5-3.5-fold increase over pre-flow levels). The Cl - current desensitized slowly in response to sustained flow, and step increases in shear stress elicited increased current only if the shear stress levels were below the 3.5 dynes/cm2 saturation level. Oscillatory flow with a physiological oscillation frequency of 1 Hz, as occurs in disturbed flow zones prone to atherosclerosis, failed to elicit the Cl- current, whereas lower oscillation frequencies led to partial recovery of the current. Nonreversing pulsatile flow, generally considered protective of atherosclerosis, was as effective in eliciting the current as steady flow. Measurements using fluids of different viscosities indicated that the Cl - current is responsive to shear stress rather than shear rate. Blocking the flow-activated Cl- current abolished flow-induced Akt phosphorylation in BAECs, whereas blocking flow-sensitive K+ currents had no effect, suggesting that flow-activated Cl- channels play an important role in regulating EC flow signaling.
UR - http://www.scopus.com/inward/record.url?scp=33845972654&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33845972654&partnerID=8YFLogxK
U2 - 10.1074/jbc.M605866200
DO - 10.1074/jbc.M605866200
M3 - Article
C2 - 16973617
AN - SCOPUS:33845972654
VL - 281
SP - 36492
EP - 36500
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 48
ER -