TY - JOUR
T1 - ACOX3 Dysfunction as a Potential Cause of Recurrent Spontaneous Vasospasm of Internal Carotid Artery
AU - Kim, Joon-Tae
AU - Won, So Yeon
AU - Kang, Kyung Wook
AU - Kim, Sang-Hoon
AU - Park, Man-Seok
AU - Choi, Kang-Ho
AU - Nam, Tai-Seung
AU - Denis, Simone W.
AU - Ferdinandusse, Sacha
AU - Lee, Ji Eun
AU - Choi, Seok-Yong
AU - Kim, Myeong-Kyu
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Recurrent spontaneous vasospasm of the extracranial internal carotid artery (RSV-eICA) is a rarely recognized cause of ischemic stroke in young adults. However, its pathophysiology remains largely unknown. Through whole-exome sequencing of the ACOX3 gene of two dizygotic Korean twin brothers affected by RSV-eICA, we identified two compound heterozygous missense variants c.235 T > G (p.F79 V) and c.665G > A (p.G222E). In silico analysis indicated that both variants were classified as pathogenic. In vitro ACOX3 enzyme assay indicated practically no enzyme activity in both F79 V and G222E mutants. To determine the effect of the mutants on vasospasm, we used a collagen contraction assay on human aortic smooth muscle cells (HASMC). Carbachol, a cholinergic agonist, induces contraction of HASMC. Knockdown of ACOX3 in HASMC, using siRNA, significantly repressed HASMC contraction triggered by carbachol. The carbachol-induced HASMC contraction was restored by transfection with plasmids encoding siRNA-resistant wild-type ACOX3, but not by transfection with ACOX3 G222E or by co-transfection with ACOX3 F79 V and ACOX3 G222E, indicating that the two ACOX3 mutants suppress carbachol-induced HASMC contraction. We propose that an ACOX3 dysfunction elicits a prolonged loss of the basal aortic myogenic tone. As a result, smooth muscles of the ICA’s intermediate segment, in which the sympathetic innervation is especially rich, becomes hypersensitive to sympathomimetic stimuli (e.g., heavy exercise) leading to a recurrent vasospasm. Therefore, ACOX3 dysfunction would be a causal mechanism of RSV-eICA. For the first time, we report the possible involvement of ACOX3 in maintaining the basal myogenic tone of human arterial smooth muscle.
AB - Recurrent spontaneous vasospasm of the extracranial internal carotid artery (RSV-eICA) is a rarely recognized cause of ischemic stroke in young adults. However, its pathophysiology remains largely unknown. Through whole-exome sequencing of the ACOX3 gene of two dizygotic Korean twin brothers affected by RSV-eICA, we identified two compound heterozygous missense variants c.235 T > G (p.F79 V) and c.665G > A (p.G222E). In silico analysis indicated that both variants were classified as pathogenic. In vitro ACOX3 enzyme assay indicated practically no enzyme activity in both F79 V and G222E mutants. To determine the effect of the mutants on vasospasm, we used a collagen contraction assay on human aortic smooth muscle cells (HASMC). Carbachol, a cholinergic agonist, induces contraction of HASMC. Knockdown of ACOX3 in HASMC, using siRNA, significantly repressed HASMC contraction triggered by carbachol. The carbachol-induced HASMC contraction was restored by transfection with plasmids encoding siRNA-resistant wild-type ACOX3, but not by transfection with ACOX3 G222E or by co-transfection with ACOX3 F79 V and ACOX3 G222E, indicating that the two ACOX3 mutants suppress carbachol-induced HASMC contraction. We propose that an ACOX3 dysfunction elicits a prolonged loss of the basal aortic myogenic tone. As a result, smooth muscles of the ICA’s intermediate segment, in which the sympathetic innervation is especially rich, becomes hypersensitive to sympathomimetic stimuli (e.g., heavy exercise) leading to a recurrent vasospasm. Therefore, ACOX3 dysfunction would be a causal mechanism of RSV-eICA. For the first time, we report the possible involvement of ACOX3 in maintaining the basal myogenic tone of human arterial smooth muscle.
KW - ACOX3
KW - Collagen contraction assay
KW - Internal carotid artery
KW - Vasospasm
KW - Whole exome sequencing
UR - http://www.scopus.com/inward/record.url?scp=85078346410&partnerID=8YFLogxK
U2 - https://doi.org/10.1007/s12975-020-00779-z
DO - https://doi.org/10.1007/s12975-020-00779-z
M3 - Article
C2 - 31975215
SN - 1868-4483
VL - 11
SP - 1041
EP - 1051
JO - Translational Stroke Research
JF - Translational Stroke Research
IS - 5
ER -