TY - JOUR
T1 - Calcium current homeostasis and synaptic deficits in hippocampal neurons from Kelch-like 1 knockout mice
AU - Perissinotti, Paula P.
AU - Ethington, Elizabeth A.
AU - Almazan, Erik
AU - Martinez-Hernandez, Elizabeth
AU - Kalil, Jennifer
AU - Koob, Michael D.
AU - Piedras-Renteria, Erika S.
N1 - Publisher Copyright:
© 2015 Perissinotti, Ethington, Almazan, Martinez-Hernandez, Kalil, Koob and Piedras-Renteria.
PY - 2015/1/5
Y1 - 2015/1/5
N2 - Kelch-like 1 (KLHL1) is a neuronal actin-binding protein that modulates voltage-gated Cav2.1 (P/Q-type) and CaV3.2 (α1H T-type) calcium channels; KLHL1 knockdown experiments (KD) cause down-regulation of both channel types and altered synaptic properties in cultured rat hippocampal neurons (Perissinotti et al., 2014). Here, we studied the effect of ablation of KLHL1 on calcium channel function and synaptic properties in cultured hippocampal neurons from KLHL1 knockout (KO) mice. Western blot data showed the P/Q-type channel α1A subunit was less abundant in KO hippocampus compared to wildtype (WT); and P/Q-type calcium currents were smaller in KO neurons than WT during early days in vitro, although this decrease was compensated for at late stages by increases in L-type calcium current. In contrast, T-type currents did not change in culture. However, biophysical properties and western blot analysis revealed a differential contribution of T-type channel isoforms in the KO, with CaV3.2 α1H subunit being down-regulated and CaV3.1 α1G up-regulated. Synapsin I levels were also reduced in the KO hippocampus and cultured neurons displayed a concomitant reduction in synapsin I puncta and decreased miniature excitatory postsynaptic current (mEPSC) frequency. In summary, genetic ablation of the calcium channel modulator resulted in compensatory mechanisms to maintain calcium current homeostasis in hippocampal KO neurons; however, synaptic alterations resulted in a reduction of excitatory synapse number, causing an imbalance of the excitatory-inhibitory synaptic input ratio favoring inhibition.
AB - Kelch-like 1 (KLHL1) is a neuronal actin-binding protein that modulates voltage-gated Cav2.1 (P/Q-type) and CaV3.2 (α1H T-type) calcium channels; KLHL1 knockdown experiments (KD) cause down-regulation of both channel types and altered synaptic properties in cultured rat hippocampal neurons (Perissinotti et al., 2014). Here, we studied the effect of ablation of KLHL1 on calcium channel function and synaptic properties in cultured hippocampal neurons from KLHL1 knockout (KO) mice. Western blot data showed the P/Q-type channel α1A subunit was less abundant in KO hippocampus compared to wildtype (WT); and P/Q-type calcium currents were smaller in KO neurons than WT during early days in vitro, although this decrease was compensated for at late stages by increases in L-type calcium current. In contrast, T-type currents did not change in culture. However, biophysical properties and western blot analysis revealed a differential contribution of T-type channel isoforms in the KO, with CaV3.2 α1H subunit being down-regulated and CaV3.1 α1G up-regulated. Synapsin I levels were also reduced in the KO hippocampus and cultured neurons displayed a concomitant reduction in synapsin I puncta and decreased miniature excitatory postsynaptic current (mEPSC) frequency. In summary, genetic ablation of the calcium channel modulator resulted in compensatory mechanisms to maintain calcium current homeostasis in hippocampal KO neurons; however, synaptic alterations resulted in a reduction of excitatory synapse number, causing an imbalance of the excitatory-inhibitory synaptic input ratio favoring inhibition.
KW - ACTIN-binding proteins
KW - HVA
KW - Kelch-like 1 protein
KW - LVA
KW - P/Q-type voltage-gated calcium channels
KW - SCA8
KW - Synapsin I
KW - T-type voltage-gated calcium channels
UR - http://www.scopus.com/inward/record.url?scp=84920625180&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84920625180&partnerID=8YFLogxK
U2 - 10.3389/fncel.2014.00444
DO - 10.3389/fncel.2014.00444
M3 - Article
C2 - 25610372
AN - SCOPUS:84920625180
SN - 1662-5102
VL - 8
JO - Frontiers in Cellular Neuroscience
JF - Frontiers in Cellular Neuroscience
IS - JAN
M1 - 444
ER -