Deletion of the mouse RegIIIbeta (Reg2) gene disrupts ciliary neurotrophic factor signaling and delays myelination of mouse cranial motor neurons.

A large number of cytokines and growth factors support the development and subsequent maintenance of postnatal motor neurons. RegIIIbeta, also known as Reg2 in rat and HIP/PAP1 in humans, is a member of a family of growth factors found in many areas of the body and previously shown to play an important role in both the development and regeneration of subsets of motor neurons. It has been suggested that RegIIIbeta expressed by motor neurons is both an obligatory intermediate in the downstream signaling of the leukemia inhibitory factor/ciliary neurotrophic factor (CNTF) family of cytokines, maintaining the integrity of motor neurons during development, as well as a powerful influence on Schwann cell growth during regeneration of the peripheral nerve. Here we report that in mice with a deletion of the RegIIIbeta gene, motor neuron survival was unaffected up to 28 weeks after birth. However, there was no CNTF-mediated rescue of neonatal facial motor neurons after axotomy in KO animals when compared with wild-type. In mice, RegIIIbeta positive motor neurons are concentrated in cranial motor nuclei that are involved in the patterning of swallowing and suckling. We found that suckling was impaired in RegIIIbeta KO mice and correlated this with a significant delay in myelination of the hypoglossal nerve. In summary, we propose that RegIIIbeta has an important role to play in the developmental fine-tuning of neonatal motor behaviors mediating the response to peripherally derived cytokines and growth factors and regulating the myelination of motor axons.

Does epigenetic 'memory' of early-life stress predispose to chronic pain in later life? A potential role for the stress regulator FKBP5.

Animal behaviours are affected not only by inherited genes but also by environmental experiences. For example, in both rats and humans, stressful early-life events such as being reared by an inattentive mother can leave a lasting trace and affect later stress response in adult life. This is owing to a chemical trace left on the chromatin attributed to so-called epigenetic mechanisms. Such an epigenetic trace often has consequences, sometimes long-lasting, on the functioning of our genes, thereby allowing individuals to rapidly adapt to a new environment. One gene under such epigenetic control is FKBP5, the gene that encodes the protein FKPB51, a crucial regulator of the stress axis and a significant driver of chronic pain states. In this article, we will discuss the possibility that exposure to stress could drive the susceptibly to chronic pain via epigenetic modifications of genes within the stress axis such as FKBP5. The possibility that such modifications, and therefore, the susceptibility to chronic pain, could be transmitted across generations in mammals and whether such mechanisms may be evolutionarily conserved across phyla will also be debated. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.

High-risk genotype for type 1 diabetes: a new simple microtiter plate-based ELOSA assay.

The main contribution to genetic susceptibility for type 1 diabetes (T1D) is conferred by the HLA class II genes, with a major involvement of the DQB1*02 and 0302 alleles. The aim of our study was to develop a simple and rapid method suitable for identifying individuals with an HLA-associated T1D risk using whole blood as a source of DNA and reverse hybridization on microtiter plates (ELOSA). DNA was extracted from whole blood using various extraction methods. The PCR-amplified second exon of the DQB1 gene was hybridized at 37 degrees C for 1 hr to a set of 11 capture probes immobilized on a microtiter plate (eight-well strip per test) and corresponding to T1D susceptibility (S), protection (P), or neutral (N) alleles. Colorimetric analysis was then performed using specific oligonucleotides coupled to horseradish peroxidase and OrthoPhenyl Peroxidase (OPD) substrate. DNA samples corresponding to French (Rhône-Alpes area) T1D patients (n = 128) have been genotyped with the HLA-T1D prototype. A strong correlation is observed between susceptible genotypes and the disease, because 92.2% of the T1D individuals screened have at least one susceptible allele (DQB1*02 or *0302), thereby strengthening interest in analyzing DQB1 alleles as HLA-linked T1D markers in our Rhône-Alpes area population. Interestingly, clear T1D-associated genotyping results have been observed when using DNA samples extracted from dried blood spots, making it possible to envisage such genotyping in geographically dispersed affected families, for large-scale newborn screening, and for the inclusion of high-risk patients in clinical trials aimed at preventing the disease.

Novel molecular correlates of endocannabinoid-mediated fear-conditioned analgesia in rats.

BACKGROUND: Fear-conditioned analgesia (FCA) is the profound suppression of pain during exposure to conditioned aversive stimuli and is mediated at spinal and supraspinal levels. The endocannabinoid system plays a key role in FCA. This study investigated brain and spinal cord expression of genes implicated in pain- and fear-related plasticity (Zif268 and Sgk1), following expression of formalin-evoked nociception, contextual fear or endocannabinoid-mediated FCA. METHODS: Adult male Lister-Hooded rats received intra-plantar injection of formalin or saline, with or without administration of the CB1 receptor antagonist AM251 (3 mg/kg, i.p.) or vehicle, 30 min prior to re-exposure to an arena paired 24 h previously with footshock. Real time quantitative polymerase chain reaction was used to measure expression of Zif268 and Sgk1 mRNA in the dorsal horn of the spinal cord (DHSC) and rostral ventromedial medulla (RVM) 30 min following arena re-exposure. RESULTS: Intra-plantar injection of formalin resulted in an increase in Zif268 and Sgk1 mRNA expression in the ipsilateral DHSC of non-fear-conditioned rats, effects not observed in rats expressing FCA. Systemic administration of the CB1 receptor antagonist/inverse agonist AM251 attenuated both FCA and the FCA-associated suppression of Zif268 expression in the ipsilateral DHSC without affecting expression of Sgk1. Conditioned fear was associated with an increase in Zif268 mRNA expression in the RVM of saline-, but not formalin-treated rats. CONCLUSIONS: The present findings suggest that Zif268 in the DHSC is an important molecular correlate of endocannabinoid-mediated FCA, and that fear-related expression of Zif268 in the RVM is influenced by the presence of nociceptive tone.