Interactions between neuroactive steroids and reelin haploinsufficiency in Purkinje cell survival.
We determined total Purkinje cell (PC) numbers in cerebella of wild-type (+/+) and heterozygous (rl/+) reeler mice of either sex during early postnatal development; in parallel, we quantified levels of neuroactive steroids in the cerebellum with mass spectrometry. We also quantified reelin mRNA and protein expression with RT-PCR and Western blotting. PC numbers are selectively reduced at postnatal day 15 (P15) in rl/+ males in comparison to +/+ males, +/+ females, and rl/+ females. Administration of 17beta-estradiol (17beta-E) into the cisterna magna at P5 increases PC numbers in rl/+ males, but not in the other groups; conversely, estrogen antagonists 4-OH-tamoxifen or ICI 182,780 reduce PC numbers in +/+ and rl/+ females, but have no effect in males. Testosterone (T) levels at P5 are much higher in males than in females, reflecting the perinatal testosterone surge in males. In addition, rl/+ male cerebella at P5 show a peculiar hormonal profile in comparison with the other groups, consisting of increased levels of T and 17beta-E, and decreased levels of dihydrotestosterone. RT-PCR analysis indicated that heterozygosity leads to a 50% reduction of reelin mRNA in the cerebellum in both sexes, as expected, and that 17beta-E upregulates reelin mRNA, particularly in rl/+ males; reelin mRNA upregulation is associated with an increase of all major reelin isoforms. These effects may represent a novel model of how reelin deficiency interacts with variable perinatal levels of neuroactive steroids, leading to gender-dependent differences in genetic vulnerability.
Biamonte
Filippo
F
Laboratory of Developmental Neuroscience and Neural Plasticity, University Campus Bio-Medico, Via Alvaro del Portillo 21, 00128 Rome, Italy.
Assenza
Giovanni
G
Marino
Ramona
R
D'Amelio
Marcello
M
Panteri
Roger
R
Caruso
Donatella
D
Scurati
Samuele
S
Yague
Josue Garcia
JG
Garcia-Segura
Luis Miguel
LM
Cesa
Roberta
R
Strata
Piergiorgio
P
Melcangi
Roberto Cosimo
RC
Keller
Flavio
F
D000818:Animals; D000831:Animals, Newborn; D001141:Aromatase / Q000378:metabolism; D001921:Brain / Q000166:cytology; D064026:Calbindins; D015816:Cell Adhesion Molecules, Neuronal / Q000172:deficiency* / Q000235:genetics; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D002853:Chromatography, Liquid / Q000379:methods; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D016326:Extracellular Matrix Proteins / Q000172:deficiency* / Q000235:genetics; D005260:Female; D000077267:Fulvestrant; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D009419:Nerve Tissue Proteins / Q000172:deficiency* / Q000235:genetics; D010088:Oxidoreductases / Q000378:metabolism; D011689:Purkinje Cells / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D000091042:Reelin Protein; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D012697:Serine Endopeptidases / Q000172:deficiency* / Q000235:genetics; D012737:Sex Factors; D013256:Steroids / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013739:Testosterone / Q000378:metabolism
D064026:Calbindins; D015816:Cell Adhesion Molecules, Neuronal; D004965:Estrogen Antagonists; D004967:Estrogens; D016326:Extracellular Matrix Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D000091042:Reelin Protein; D064030:S100 Calcium Binding Protein G; D013256:Steroids; D000077267:Fulvestrant; D013739:Testosterone; D004958:Estradiol; D010088:Oxidoreductases; D001141:Aromatase; C000717128:Reln protein, mouse; D012697:Serine Endopeptidases