TY - JOUR
T1 - PCB 136 atropselectively alters morphometric and functional parameters of neuronal connectivity in cultured rat hippocampal neurons via ryanodine receptor-dependent mechanisms
AU - Yang, Dongren
AU - Kania-Korwel, Izabela
AU - Ghogha, Atefeh
AU - Chen, Hao
AU - Stamou, Marianna
AU - Bose, Diptiman D.
AU - Pessah, Isaac N
AU - Lehmler, Hans Joachim
AU - Lein, Pamela J
PY - 2014
Y1 - 2014
N2 - We recently demonstrated that polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substitutions sensitize ryanodine receptors (RyRs), and this activity promotes Ca2+-dependent dendritic growth in cultured neurons. Many ortho-substituted congeners display axial chirality, and we previously reported that the chiral congener PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) atropselectively sensitizes RyRs. Here, we test the hypothesis that PCB 136 atropisomers differentially alter dendritic growth and other parameters of neuronal connectivity influenced by RyR activity. (-)-PCB 136, which potently sensitizes RyRs, enhances dendritic growth in primary cultures of rat hippocampal neurons, whereas (+)-PCB 136, which lacks RyR activity, has no effect on dendritic growth. The dendrite-promoting activity of (-)-PCB 136 is observed at concentrations ranging from 0.1 to 100nM and is blocked by pharmacologic RyR antagonism. Neither atropisomer alters axonal growth or cell viability. Quantification of PCB 136 atropisomers in hippocampal cultures indicates that atropselective effects on dendritic growth are not due to differential partitioning of atropisomers into cultured cells. Imaging of hippocampal neurons loaded with Ca2+-sensitive dye demonstrates that (-)-PCB 136 but not (+)-PCB 136 increases the frequency of spontaneous Ca2+ oscillations. Similarly, (-)-PCB 136 but not (+)-PCB 136 increases the activity of hippocampal neurons plated on microelectrode arrays. These data support the hypothesis that atropselective effects on RyR activity translate into atropselective effects of PCB 136 atropisomers on neuronal connectivity, and suggest that the variable atropisomeric enrichment of chiral PCBs observed in the human population may be a significant determinant of individual susceptibility for adverse neurodevelopmental outcomes following PCB exposure.
AB - We recently demonstrated that polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substitutions sensitize ryanodine receptors (RyRs), and this activity promotes Ca2+-dependent dendritic growth in cultured neurons. Many ortho-substituted congeners display axial chirality, and we previously reported that the chiral congener PCB 136 (2,2',3,3',6,6'-hexachlorobiphenyl) atropselectively sensitizes RyRs. Here, we test the hypothesis that PCB 136 atropisomers differentially alter dendritic growth and other parameters of neuronal connectivity influenced by RyR activity. (-)-PCB 136, which potently sensitizes RyRs, enhances dendritic growth in primary cultures of rat hippocampal neurons, whereas (+)-PCB 136, which lacks RyR activity, has no effect on dendritic growth. The dendrite-promoting activity of (-)-PCB 136 is observed at concentrations ranging from 0.1 to 100nM and is blocked by pharmacologic RyR antagonism. Neither atropisomer alters axonal growth or cell viability. Quantification of PCB 136 atropisomers in hippocampal cultures indicates that atropselective effects on dendritic growth are not due to differential partitioning of atropisomers into cultured cells. Imaging of hippocampal neurons loaded with Ca2+-sensitive dye demonstrates that (-)-PCB 136 but not (+)-PCB 136 increases the frequency of spontaneous Ca2+ oscillations. Similarly, (-)-PCB 136 but not (+)-PCB 136 increases the activity of hippocampal neurons plated on microelectrode arrays. These data support the hypothesis that atropselective effects on RyR activity translate into atropselective effects of PCB 136 atropisomers on neuronal connectivity, and suggest that the variable atropisomeric enrichment of chiral PCBs observed in the human population may be a significant determinant of individual susceptibility for adverse neurodevelopmental outcomes following PCB exposure.
KW - Atropselectivity
KW - Chirality
KW - Dendritic growth
KW - Developmental neurotoxicity
KW - Neuronal connectivity
KW - Polychlorinated biphenyls
KW - Ryanodine receptor
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U2 - 10.1093/toxsci/kft334
DO - 10.1093/toxsci/kft334
M3 - Article
C2 - 24385416
AN - SCOPUS:84894262438
VL - 138
SP - 379
EP - 392
JO - Toxicological Sciences
JF - Toxicological Sciences
SN - 1096-6080
IS - 2
ER -