TY - JOUR
T1 - Human pregnancy zone protein stabilizes misfolded proteins including preeclampsia- and Alzheimer's-associated amyloid beta peptide
AU - Cater, Jordan H.
AU - Kumita, Janet R.
AU - Abdallah, Rafaa Zeineddine
AU - Zhao, Guomao
AU - Bernardo-Gancedo, Ana
AU - Henry, Amanda
AU - Winata, Wendy
AU - Chi, Mengna
AU - Grenyer, Brin S F
AU - Townsend, Michelle L.
AU - Ranson, Marie
AU - Buhimschi, Catalin S
AU - Charnock-Jones, D. Stephen
AU - Dobson, Christopher M
AU - Wilson, Mark R.
AU - Buhimschi, Irina A.
AU - Wyatt, Amy R.
N1 - This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).
PY - 2019/3/26
Y1 - 2019/3/26
N2 - Protein misfolding underlies the pathology of a large number of human disorders, many of which are age-related. An exception to this is preeclampsia, a leading cause of pregnancy-associated morbidity and mortality in which misfolded proteins accumulate in body fluids and the placenta. We demonstrate that pregnancy zone protein (PZP), which is dramatically elevated in maternal plasma during pregnancy, efficiently inhibits in vitro the aggregation of misfolded proteins, including the amyloid beta peptide (Aß) that is implicated in preeclampsia as well as with Alzheimer's disease. The mechanism by which this inhibition occurs involves the formation of stable complexes between PZP and monomeric Aß or small soluble Aß oligomers formed early in the aggregation pathway. The chaperone activity of PZP is more efficient than that of the closely related protein alpha-2-macroglobulin (a2M), although the chaperone activity of a2M is enhanced by inducing its dissociation into PZP-like dimers. By immunohistochemistry analysis, PZP is found primarily in extravillous trophoblasts in the placenta. In severe preeclampsia, PZP-positive extravillous trophoblasts are adjacent to extracellular plaques containing Aß, but PZP is not abundant within extracellular plaques. Our data support the conclusion that the up-regulation of PZP during pregnancy represents a major maternal adaptation that helps to maintain extracellular proteostasis during gestation in humans. We propose that overwhelming or disrupting the chaperone function of PZP could underlie the accumulation of misfolded proteins in vivo. Attempts to characterize extracellular proteostasis in pregnancy will potentially have broad-reaching significance for understanding disease-related protein misfolding.
AB - Protein misfolding underlies the pathology of a large number of human disorders, many of which are age-related. An exception to this is preeclampsia, a leading cause of pregnancy-associated morbidity and mortality in which misfolded proteins accumulate in body fluids and the placenta. We demonstrate that pregnancy zone protein (PZP), which is dramatically elevated in maternal plasma during pregnancy, efficiently inhibits in vitro the aggregation of misfolded proteins, including the amyloid beta peptide (Aß) that is implicated in preeclampsia as well as with Alzheimer's disease. The mechanism by which this inhibition occurs involves the formation of stable complexes between PZP and monomeric Aß or small soluble Aß oligomers formed early in the aggregation pathway. The chaperone activity of PZP is more efficient than that of the closely related protein alpha-2-macroglobulin (a2M), although the chaperone activity of a2M is enhanced by inducing its dissociation into PZP-like dimers. By immunohistochemistry analysis, PZP is found primarily in extravillous trophoblasts in the placenta. In severe preeclampsia, PZP-positive extravillous trophoblasts are adjacent to extracellular plaques containing Aß, but PZP is not abundant within extracellular plaques. Our data support the conclusion that the up-regulation of PZP during pregnancy represents a major maternal adaptation that helps to maintain extracellular proteostasis during gestation in humans. We propose that overwhelming or disrupting the chaperone function of PZP could underlie the accumulation of misfolded proteins in vivo. Attempts to characterize extracellular proteostasis in pregnancy will potentially have broad-reaching significance for understanding disease-related protein misfolding.
KW - protein misfolding
KW - molecular chaperone
KW - proteostasis
U2 - 10.1073/pnas.1817298116
DO - 10.1073/pnas.1817298116
M3 - Article
SN - 0027-8424
VL - 116
SP - 6101
EP - 6110
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 13
ER -