Treatment of PC12 cells with nerve growth factor increases iron uptake.
Phaeochromocytoma PC12 cells treated with nerve growth factor (NGF) differentiate into a neuronal phenotype. Here we compare the uptake of transferrin-bound and non-transferrin-bound iron in NGF-treated (neuronal phenotype) and control (proliferating) PC12 cells. The non-transferrin-bound iron uptake was greater in the NGF-treated cells than in the control, independently of the uptake time, the iron-chelating agents used, the oxidation state of iron (Fe(2+) or Fe(3+)) and the iron concentration tested. The NGF-treated cells expressed L-type and N-type voltage-operated Ca(2+) channels. Nitrendipine (an L-type inhibitor) and possibly omega-conotoxin (an N-type inhibitor) inhibited the iron uptake by 20%. Thapsigargin inhibits the endoplasmic reticulum Ca(2+) pump and allowed Mn(2+) entry into cells. Preincubating PC12 cells with thapsigargin increased the iron uptake. The rate of transferrin-bound iron uptake was less than 1% of the non-transferrin-bound iron uptake and the maximum transferrin-bound iron uptake was also very low. We conclude that an increase in the iron uptake by multiple pathways accompanies the transition of PC12 cells from the proliferating to the neuronal phenotype.
Mwanjewe
J
J
Department of Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5.
Hui
B K
BK
Coughlin
M D
MD
Grover
A K
AK
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D020932:Nerve Growth Factor / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D016716:PC12 Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D013997:Time Factors; D014168:Transferrin / Q000378:metabolism*
D014168:Transferrin; D020932:Nerve Growth Factor; D007501:Iron; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496322:Nos1 protein, rat; D002118:Calcium