No abstract

Several mutations are known or suspected to affect mRNA splicing of CYP2C19, CYP2D6 and CYP3A5 genes; however, little experimental evidence exists to support these conclusions. The present study applies mathematical models that measure changes in information content of splice sites in these genes to demonstrate the relationship between the predicted phenotypes of these variants to the corresponding genotypes. Based on information analysis, the CYP2C19*2 variant activates a new cryptic site 40 nucleotides downstream of the natural splice site. CYP2C19*7 abolishes splicing at the exon 5 donor site. The CYP2D6*4 allele similarly inactivates splicing at the acceptor site of exon 4 and activates a new cryptic site one nucleotide downstream of the natural acceptor. CYP2D6*11 inactivates the acceptor site of exon 2. The CYP3A5*3 allele activates a new cryptic site 236 nucleotides upstream of the exon 4 natural acceptor site. CYP3A5*5 inactivates the exon 5 donor site and CYP3A5*6 strengthens a site upstream of the natural donor site, resulting in skipping of exon 7. Other previously described missense and nonsense mutations at terminal codons of exons in these genes affected splicing. CYP2D6*8 and CYP2D6*14 both decrease the strength of the exon 3 donor site, producing transcripts lacking this exon. The results of information analysis are consistent with the poor metabolizer phenotypes observed in patients with these mutations, and illustrate the potential value of these mathematical models to quantitatively evaluate the functional consequences of new mutations suspected of altering mRNA splicing.

Although migraine is more common in women than men and often linked to the menstrual cycle, few studies have investigated the biological basis of hormonal influences on the trigeminovascular system. In the present study we investigated the effect of physiological levels (10(-9) m) oestrogen on female rat trigeminal ganglia in vitro. Immunocytochemical analysis demonstrated the presence of oestrogen receptor-alpha in a predominantly cytoplasmic location and in neurites. Microarray analysis demonstrated that oestrogen treatment regulates several genes with potential relevance to menstrual migraine. The genes that were upregulated included synapsin-2, endothelin receptor type B, activity and neurotransmitter-induced early gene 7 (ania-7), phosphoserine aminotransferase, MHC-1b, and ERK-1. Down-regulated genes included IL-R1, bradykinin B2 receptor, N-tropomodulin, CCL20, GABA transporter protein, fetal intestinal lactase-phlorizin hydrolase, carcinoembryonic antigen-related protein, zinc finger protein 36, epsin 1 and cysteine string protein. Protein activity assays demonstrated that exposure of the cultured neurons to oestrogen leads to activation of ERK, which has been linked to inflammatory pain. Immunocytochemistry demonstrated that activated ERK was present in neurons containing peripherin, a marker of nociceptive neurons. Several of the genes in the present study may provide potential targets for understanding the association of oestrogen with migraine and other hormone-related orofacial pain.

In this study, forelimb organizations and output properties of the supplementary motor area (SMA) and the dorsal cingulate motor area (CMAd) were assessed and compared with primary motor cortex (M1). Stimulus-triggered averages of electromyographic activity from 24 muscles of the forelimb were computed from layer V sites of 2 rhesus monkeys performing a reach-to-grasp task. No clear segregation of the forelimb representation of proximal and distal muscles was found in SMA. In CMAd, sites producing poststimulus effects in proximal muscles tended to be located caudal to distal muscle sites, although the number of effects was limited. For both SMA and CMAd, facilitation effects were more prevalent in distal than in proximal muscles. At an intensity of 60 microA, the mean latencies of M1 facilitation effects were 8 and 12.1 ms shorter and the magnitudes approximately 10 times greater than those from SMA and CMAd. Our results show that corticospinal neurons in SMA and CMAd provide relatively weak input to spinal motoneurons compared with the robust effects from M1. However, a small number of facilitation effects from SMA and CMAd had latencies as short as the shortest ones from M1 suggesting a minimum linkage to motoneurons as direct as that from M1.

It is unclear how sublethal hypoxia affects lung development. To investigate the effects of chronic hypoxia on postnatal lung remodeling, we treated neonatal rats with FIO 2 of 0.12 for 10 d and analyzed lung development by morphometry and gene expression by DNA microarray. Our results showed the neonatal rats exposed to hypoxia reduced body weight by 42% and wet lung weight by 32% compared with the neonatal rats exposed to normoxia. In the neonatal rats exposed to hypoxia, the radial alveolar counts were decreased to 5.6 from 7.9 and the mean linear intercepts were increased to 56.5 m from 38.2 m. In DNA microarray analysis, approximately half of probed genes were unknown. Chronic hypoxia significantly regulated expression of genes that are involved in pathogenesis of pulmonary hypertension and postnatal lung remodeling. Chemokine ligand 12, jagged 2 were among those upregulated; c-kit, ephrin A1, and Hif-2␣ were among those downregulated. The altered expression of those genes was correlated with the lung development and remodeling. (Pediatr Res 64: 56-62, 2008)