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Assessing the contribution of thrombospondin-4 induction and ATF6α activation to endoplasmic reticulum expansion and phenotypic modulation in bladder outlet obstruction

Krawczyk, Katarzyna K. LU ; Ekman, Mari LU ; Rippe, Catarina LU ; Grossi, Mario LU ; Nilsson, Bengt Olof LU ; Albinsson, Sebastian LU ; Uvelius, Bengt LU and Swärd, Karl LU (2016) In Scientific Reports 6.
Abstract

Phenotypic modulation of smooth muscle cells is a hallmark of disease. The associated expansion of endoplasmic reticulum (ER) volume remains unexplained. Thrombospondin-4 was recently found to promote ATF6α activation leading to ER expansion. Using bladder outlet obstruction as a paradigm for phenotypic modulation, we tested if thrombospondin-4 is induced in association with ATF6α activation and ER expansion. Thrombospondin-4 was induced and ATF6α was activated after outlet obstruction in rodents. Increased abundance of spliced of Xbp1, another ER-stress sensor, and induction of Atf4 and Creb3l2 was also seen. Downstream of ATF6α, Calr, Manf, Sdf2l1 and Pdi increased as did ER size, whereas contractile markers were reduced.... (More)

Phenotypic modulation of smooth muscle cells is a hallmark of disease. The associated expansion of endoplasmic reticulum (ER) volume remains unexplained. Thrombospondin-4 was recently found to promote ATF6α activation leading to ER expansion. Using bladder outlet obstruction as a paradigm for phenotypic modulation, we tested if thrombospondin-4 is induced in association with ATF6α activation and ER expansion. Thrombospondin-4 was induced and ATF6α was activated after outlet obstruction in rodents. Increased abundance of spliced of Xbp1, another ER-stress sensor, and induction of Atf4 and Creb3l2 was also seen. Downstream of ATF6α, Calr, Manf, Sdf2l1 and Pdi increased as did ER size, whereas contractile markers were reduced. Overexpression of ATF6α, but not of thrombospondin-4, increased Calr, Manf, Sdf2l1 and Pdi and caused ER expansion, but the contractile markers were inert. Knockout of thrombospondin-4 neither affected bladder growth nor expression of ATF6α target genes, and repression of contractile markers was the same, even if ATF6α activation was curtailed. Increases of Xbp1s, Atf4 and Creb3l2 were similar. Our findings demonstrate reciprocal regulation of the unfolded protein response, including ATF6α activation and ER expansion, and reduced contractile differentiation in bladder outlet obstruction occurring independently of thrombospondin-4, which however is a sensitive indicator of obstruction.

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organization
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Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
6
publisher
Nature Publishing Group
external identifiers
  • scopus:84985912179
  • wos:000382331000001
ISSN
2045-2322
DOI
10.1038/srep32449
language
English
LU publication?
yes
id
f480417d-404f-4d54-b49d-61c909cf2cbc
date added to LUP
2016-11-11 15:02:34
date last changed
2017-06-04 04:54:05
@article{f480417d-404f-4d54-b49d-61c909cf2cbc,
  abstract     = {<p>Phenotypic modulation of smooth muscle cells is a hallmark of disease. The associated expansion of endoplasmic reticulum (ER) volume remains unexplained. Thrombospondin-4 was recently found to promote ATF6α activation leading to ER expansion. Using bladder outlet obstruction as a paradigm for phenotypic modulation, we tested if thrombospondin-4 is induced in association with ATF6α activation and ER expansion. Thrombospondin-4 was induced and ATF6α was activated after outlet obstruction in rodents. Increased abundance of spliced of Xbp1, another ER-stress sensor, and induction of Atf4 and Creb3l2 was also seen. Downstream of ATF6α, Calr, Manf, Sdf2l1 and Pdi increased as did ER size, whereas contractile markers were reduced. Overexpression of ATF6α, but not of thrombospondin-4, increased Calr, Manf, Sdf2l1 and Pdi and caused ER expansion, but the contractile markers were inert. Knockout of thrombospondin-4 neither affected bladder growth nor expression of ATF6α target genes, and repression of contractile markers was the same, even if ATF6α activation was curtailed. Increases of Xbp1s, Atf4 and Creb3l2 were similar. Our findings demonstrate reciprocal regulation of the unfolded protein response, including ATF6α activation and ER expansion, and reduced contractile differentiation in bladder outlet obstruction occurring independently of thrombospondin-4, which however is a sensitive indicator of obstruction.</p>},
  articleno    = {32449},
  author       = {Krawczyk, Katarzyna K. and Ekman, Mari and Rippe, Catarina and Grossi, Mario and Nilsson, Bengt Olof and Albinsson, Sebastian and Uvelius, Bengt and Swärd, Karl},
  issn         = {2045-2322},
  language     = {eng},
  month        = {09},
  publisher    = {Nature Publishing Group},
  series       = {Scientific Reports},
  title        = {Assessing the contribution of thrombospondin-4 induction and ATF6α activation to endoplasmic reticulum expansion and phenotypic modulation in bladder outlet obstruction},
  url          = {http://dx.doi.org/10.1038/srep32449},
  volume       = {6},
  year         = {2016},
}