TY - JOUR
T1 - No evidence for cell-to-cell transmission of the unfolded protein response in cell culture
AU - van Ziel, Anna M.
AU - Wolzak, Kimberly
AU - Nölle, Anna
AU - Hoetjes, Petrus J.
AU - Berenjeno-Correa, Ernesto
AU - van Anken, Eelco
AU - Struys, Eduard A.
AU - Scheper, Wiep
N1 - © 2019 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - The unfolded protein response (UPR) is one of the major cell-autonomous proteostatic stress responses. The UPR has been implicated in the pathogenesis of neurodegenerative diseases and is therefore actively investigated as therapeutic target. In this respect, cell non-autonomous effects of the UPR including the reported cell-to-cell transmission of UPR activity may be highly important. A pharmaca-based UPR induction was employed to generate conditioned media (CM) from CM-donating neuronal (‘donor’) cells (SK-N-SH and primary mouse neurons). As previously reported, upon subsequent transfer of CM to naive neuronal ‘acceptor’ cells, we confirmed UPR target mRNA and protein expression by qPCR and automated microscopy. However, UPR target gene expression was also induced in the absence of donor cells, indicating carry-over of pharmaca. Genetic induction of single pathways of the UPR in donor cells did not result in UPR transmission to acceptor cells. Moreover, no transmission was detected upon full UPR activation by nutrient deprivation or inducible expression of the heavy chain of immunoglobulin M in donor HeLa cells. In addition, in direct co-culture of donor cells expressing the immunoglobulin M heavy chain and fluorescent UPR reporter acceptor HeLa cells, UPR transmission was not observed. In conclusion, carry-over of pharmaca is a major confounding factor in pharmaca-based UPR transmission protocols that are therefore unsuitable to study cell-to-cell UPR transmission. In addition, the absence of UPR transmission in non-pharmaca-based models of UPR activation indicates that cell-to-cell UPR transmission does not occur in cell culture. (Figure presented.).
AB - The unfolded protein response (UPR) is one of the major cell-autonomous proteostatic stress responses. The UPR has been implicated in the pathogenesis of neurodegenerative diseases and is therefore actively investigated as therapeutic target. In this respect, cell non-autonomous effects of the UPR including the reported cell-to-cell transmission of UPR activity may be highly important. A pharmaca-based UPR induction was employed to generate conditioned media (CM) from CM-donating neuronal (‘donor’) cells (SK-N-SH and primary mouse neurons). As previously reported, upon subsequent transfer of CM to naive neuronal ‘acceptor’ cells, we confirmed UPR target mRNA and protein expression by qPCR and automated microscopy. However, UPR target gene expression was also induced in the absence of donor cells, indicating carry-over of pharmaca. Genetic induction of single pathways of the UPR in donor cells did not result in UPR transmission to acceptor cells. Moreover, no transmission was detected upon full UPR activation by nutrient deprivation or inducible expression of the heavy chain of immunoglobulin M in donor HeLa cells. In addition, in direct co-culture of donor cells expressing the immunoglobulin M heavy chain and fluorescent UPR reporter acceptor HeLa cells, UPR transmission was not observed. In conclusion, carry-over of pharmaca is a major confounding factor in pharmaca-based UPR transmission protocols that are therefore unsuitable to study cell-to-cell UPR transmission. In addition, the absence of UPR transmission in non-pharmaca-based models of UPR activation indicates that cell-to-cell UPR transmission does not occur in cell culture. (Figure presented.).
KW - UPR transmission
KW - cell non-autonomous
KW - endoplasmic reticulum stress
KW - neurodegenerative diseases
KW - proteostasis
KW - unfolded protein response
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U2 - https://doi.org/10.1111/jnc.14856
DO - https://doi.org/10.1111/jnc.14856
M3 - Article
C2 - 31442299
SN - 0022-3042
VL - 152
SP - 208
EP - 220
JO - Journal of neurochemistry
JF - Journal of neurochemistry
IS - 2
ER -