Open AccessIncreased AT1 receptor expression mediates vasoconstriction leading to hypertension in Snx1−/− mice
Author(s) -
Chao Liu,
Xingyue Li,
Jinjuan Fu,
Ken Chen,
Qinyu Liao,
Jialiang Wang,
Caiyu Chen,
Hao Luo,
Pedro A. José,
Yongjian Yang,
Jian Yang,
Chunyu Zeng
Publication year - 2021
Publication title -
hypertension research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.022
H-Index - 89
eISSN - 1348-4214
pISSN - 0916-9636
DOI - 10.1038/s41440-021-00661-x
Subject(s) - angiotensin ii , endocrinology , medicine , angiotensin ii receptor type 1 , proximity ligation assay , chemistry , receptor , colocalization , downregulation and upregulation , microbiology and biotechnology , biology , biochemistry , gene
Angiotensin II type 1 receptor (AT 1 R) is a vital therapeutic target for hypertension. Sorting nexin 1 (SNX1) participates in the sorting and trafficking of the renal dopamine D 5 receptor, while angiotensin and dopamine are counterregulatory factors in the regulation of blood pressure. The effect of SNX1 on AT 1 R is not known. We hypothesized that SNX1, through arterial AT 1 R sorting and trafficking, is involved in blood pressure regulation. CRISPR/Cas9 system-generated SNX1 -/- mice showed dramatic elevations in blood pressure compared to their wild-type littermates. The angiotensin II-mediated contractile reactivity of the mesenteric arteries and AT 1 R expression in the aortas were also increased. Moreover, immunofluorescence and immunoprecipitation analyses revealed that SNX1 and AT 1 R were colocalized and interacted in the aortas of wild-type mice. In vitro studies revealed that AT 1 R protein levels and downstream calcium signaling were upregulated in A10 cells treated with SNX1 siRNA. This may have resulted from decreased AT 1 R protein degradation since the AT 1 R mRNA levels showed no changes. AT 1 R protein was less degraded when SNX1 was downregulated, as reflected by a cycloheximide chase assay. Furthermore, proteasomal rather than lysosomal inhibition increased AT 1 R protein content, and this effect was accompanied by decayed binding of ubiquitin and AT 1 R after SNX1 knockdown. Confocal microscopy revealed that AT 1 R colocalized with PSMD6, a proteasomal marker, and the colocalization was reduced after SNX1 knockdown. These findings suggest that SNX1 sorts AT 1 R for proteasomal degradation and that SNX1 impairment increases arterial AT 1 R expression, leading to increased vasoconstriction and blood pressure.