ABSTRACT
Mus musculus is the only known species from which embryonic stem cells (ESC) can be isolated under conditions requiring only leukemia inhibitory factor (LIF). Other species are non-permissive in LIF media, and form developmentally primed epiblast stem cells (EpiSC) similar to cells derived from post-implantation, egg cylinders. To evaluate whether non-permissiveness extends to induced pluripotent stem cells (iPSC), we derived iPSC from the eight founder strains of the mouse Collaborative Cross. Two strains, NOD/ShiLtJ and the WSB/EiJ, were non-permissive, consistent with the previous classification of NOD/ShiLtJ as non-permissive to ESC derivation. We determined non-permissiveness is recessive, and that non-permissive genomes do not compliment. We overcame iPSC non-permissiveness by using GSK3B and MEK inhibitors with serum, a technique we termed 2iS reprogramming. Although used for ESC derivation, GSK3B and MEK inhibitors have not been used during iPSC reprogramming because they inhibit survival of progenitor differentiated cells. iPSC derived in 2iS are more transcriptionally similar to ESC than EpiSC, indicating that 2iS reprogramming acts to overcome genetic background constraints. Finally, of species tested for ESC or iPSC derivation, only some M. musculus strains are permissive under LIF culture conditions suggesting that this is an evolutionarily derived characteristic in the M. musculus lineage.
Subject(s)
Cellular Reprogramming/genetics , Evolution, Molecular , Mice/genetics , Transcription, Genetic , Animals , Cells, Cultured , Cellular Reprogramming/drug effects , Culture Media/metabolism , Culture Media/pharmacology , Female , Fibroblasts , Glycogen Synthase Kinase 3 beta/antagonists & inhibitors , Glycogen Synthase Kinase 3 beta/metabolism , Induced Pluripotent Stem Cells , Leukemia Inhibitory Factor/metabolism , MAP Kinase Kinase Kinases/antagonists & inhibitors , MAP Kinase Kinase Kinases/metabolism , Male , Mice, Inbred Strains/genetics , Mouse Embryonic Stem Cells , Primary Cell Culture , Protein Kinase Inhibitors/pharmacology , Sex FactorsABSTRACT
A promoter polymorphism in the serotonin transporter gene has been widely studied in neuropsychiatry. We genotyped the 5-HTTLPR/rs25531 triallelic polymorphism in 728 schizophrenia cases from the CATIE study and 724 control subjects. In a logistic regression with case/control status as dependent variable and 7 ancestry-informative principal components as covariates, the effect of 5-HTTLPR/rs25531 composite genotype was not significant (odds ratio = 1.008, 95% CI 0.868-1.172, P = 0.91). In cases only, 5-HTTLPR/rs25531 was not associated with neurocognition (summary neurocognitive index P = 0.21, working memory P = 0.32) or symptomatology (PANSS positive P = 0.67 and negative symptoms P = 0.46). We were unable to identify association of the triallelic 5-HTTLPR with schizophrenia, neurocognition, or core psychotic symptoms even at levels of significance unadjusted for multiple comparisons.
