. The functional relevance of the interaction between IL1RAPL1 and NCS-1 was also suggested by the reduction of neurite elongation observed in nerve growth factor (NGF)-treated IL1RAPL1 cells, a phenotype rescued by NCS-1 inactivation. Because both proteins are highly expressed in neurons, these results suggest that IL1RAPL1-related mental retardation could result from a disruption of N-VGCC and/or NCS-1-dependent synaptic and neuronal activities.PC12 cells ͉ neuronal calcium sensor-1 ͉ X-linked mental retardation ͉ exocytosis C ognitive impairment or mental retardation (MR) affects Ϸ2% of the population, leading to moderate (IQ Ͻ70) up to severe (IQ Ͻ50) handicap. The underlying causes are extremely heterogeneous, including genetic causes, many of which are X-linked (XLMR) (1, 2). Null mutations in the IL1-receptor accessory protein-like 1 gene (IL1RAPL1) [National Center for Biotechnology Information (NCBI) accession no. NM 014271.2] have been involved in a nonsyndromic form of XLMR (3). IL1RAPL1 and the closely related protein IL1RAPL2 (NCBI accession no. NM 017416) belong to a previously unrecognized class of the interleukin-1/toll receptor family characterized by the presence of a 150-aa C terminus domain with unknown function (3, 4). IL1RAPL1 and IL1RAPL2 have specific, but not redundant, temporal and spatial expression pattern in the brain, Il1rapl1, the mouse homologue of IL1RAPL1, being specifically expressed in adult brain structures that are known to be involved in the hippocampal memory system (3).Most of physiological and biological properties of IL1RAPL proteins remain largely unknown. Recent studies have demonstrated that expression of IL1RAPL1 in PC12 cells leads to a profound inhibition of ATP-induced growth hormone (GH) release (4). The underlying cellular pathways remain to be elucidated; however, IL1RAPL1 has been shown to interact by way of its 150-aa C-terminal domain with the neuronal calcium sensor-1 protein (NCS-1), a protein widely expressed in neurons (5) and the related chromaffin and PC12 cells (6).NCS-1 belongs to a large Ca 2ϩ -binding protein family (7) implicated in the regulation of Ca 2ϩ -dependent exocytosis (6) through its activation of PI 4 kinase and PIP 2 formation (8-10). Moreover, NCS-1 modulates Ca 2ϩ channels trafficking and activity in various cellular models (11, 12) and has effects on synaptic transmission by way of activity-dependent facilitation of P/Q-type calcium currents at presynaptic nerve terminals (13). Finally, at the behavioral level, NCS-1 appears also to be involved in associative learning and memory (14).Here, we focus on IL1RAPL1 functions by studying the physiological impact of IL1RAPL1/NCS-1 interaction in PC12 cells, a well known model of both nerve growth factor (NGF)-induced neuronal differentiation and Ca 2ϩ -dependent exocytosis. We show that expression of IL1RAPL1 in PC12 cells, which do not normally express the IL1RAPL1 protein, mediates, through IL1RAPL1/NSC-1 interaction, a down-regulation of N-type voltage-gated calcium channel (N-VGCC) ac...

SummaryOtosclerosis is a condition characterized by an abnormal bone metabolism in the otic capsule, resulting in conductive and/or sensorineural hearing loss. Otosclerosis is a common disorder in which genes play an important role. Case-control association studies have implicated several genes in the abnormal bone metabolism associated with otosclerosis: COL1A1, TGFB1, BMP2, and BMP4. To investigate the association of these genes with otosclerosis in the Tunisian population, we examined nine single nucleotide polymorphisms (SNPs) in 159 unrelated otosclerosis patients and 155 unrelated controls. We found an association of rs11327935 in COL1A1 with otosclerosis that was shown to be sex specific. The coding polymorphism T263I in TGFB1 was also associated with otosclerosis in the Tunisian population. The effect sizes of both the associations were consistent with previous studies, as the same effect was found in all cases. The association of BMP2 and BMP4 was not significant. However, a trend towards association was found for the BMP4 gene that was consistent with earlier reports. In conclusion, this study replicates and strengthens the evidence for association between polymorphisms of COL1A1 and TGFB1 in the genetic aetiology of otosclerosis.

Autoimmune thyroid diseases are common polygenic multifactorial disorders with the environment contributing importantly to the emergence of the disease phenotype. Some of the disease manifestations, such as severe thyroid-associated ophthalmopathy, pretibial myxedema and thyroid antigen/antibody immune complex nephritis are unusual to rare. The spectrum of autoimmune thyroid diseases includes: Graves' disease (GD), Hashimoto's thyroiditis (HT), atrophic autoimmune thyroiditis, postpartum thyroiditis, painless thyroiditis unrelated to pregnancy and thyroid-associated ophthalmopathy. This spectrum present contrasts in terms of thyroid function, disease duration and spread to other anatomic location. The genetic basis of autoimmune thyroid disease (AITD) is complex and likely to be due to genes of both large and small effects. In GD the autoimmune process results in the production of thyroid-stimulating antibodies and lead to hyperthyroidism, whereas in HT the end result is destruction of thyroid cells and hypothyroidism. Recent studies in the field of autoimmune thyroid diseases have largely focused on (i) the genes involved in immune response and/or thyroid physiology with could influence susceptibility to disease, (ii) the delineation of B-cell autoepitopes recognized by the main autoantigens, thyroglobulin, thyroperoxidase and TSH receptor, to improve our understanding of how these molecules are seen by the immune system and (iii) the regulatory network controlling the synthesis of thyroid hormones and its dysfunction in AITD. The aim of the present review is to summarize the current knowledge regarding the relation existing between some susceptibility genes, autoantigens and dysfunction of thyroid function during AITD.

Deleterious mutations of SLC26A4 cause Pendred syndrome (PS), an autosomal recessive disorder comprising goitre and deafness with enlarged vestibular aqueducts (EVA), and nonsyndromic hearing loss (NSHL). However, the SLC26A4 hyperactivity was recently associated with the emergence of autoimmune thyroid diseases (AITD) and asthma among human and mouse model. Here, by direct sequencing, we investigate the sequences of the 20 coding exons (2 to 21) of SLC26A4 and their flanking intron-exon junctions among patients affected with Graves' disease (GD) hyperthyroidism. Ten mono-allelic variants were identified, seven of which are intronic and previously unreported. Two, c.898A>C (p.I300L) and c.1061T>C (p.F354S), of the three exonic variants are non synonymous. The p.F354S variant is already described to be involved in PS or NSHL inheritances. The exploration by PCR-RFLP of p.I300L and p.F354S variants among 132 GD patients, 105 Hashimoto thyroiditis (HT), 206 Healthy subjects and 102 families with NSHL have shown the presence of both variants. The p.F354S variation was identified both among patients (1~HT and 3 GD) and healthy subjects (n=5). Whereas, the p.I300L variant was identified only in GD patients (n=3). Our studies provide evidence of the importance of systematic analysis of SLC26A4 gene sequences on models other than deafness. This approach allows the identification of new variants and the review of the pathogenic effects of certain mono-allelic variants reported responsible for PS and NSHL development.

Hearing impairment (HI) is the most frequent sensory defect. Genetic causes are involved in two thirds of prelingual cases. Moreover, the autosomal recessive HI frequency is increased in countries where there is a high rate of consanguinity, such as in North African Mediterranean countries. This population shares several features, including history and social behavior, that promote the spread of founder mutations. HI is characterized by tremendous heterogeneity in both the genetic and clinical aspects. The identification of the causal mutation is important for early diagnosis, clinical follow-up, and genetic counseling. Addressing the extreme genetic heterogeneity of HI using classic molecular methods would be expensive and time-consuming. We designed a cost-effective North African Deafness chip for rapid and simultaneous analysis of 58 mutations using multiplex PCR coupled with dual-color arrayed primer extension. These mutations are found in North African HI patients and are distributed over 31 exons and five introns in 21 distinct genes. Assay specificity was initially optimized using 103 archived DNA samples of known genotypes. Blind validation of HI-unrelated patients revealed mutant alleles in 13 samples, and these mutations were confirmed by Sanger sequencing. The North African Deafness chip allows for simultaneous genotyping of eight different samples, at a minimal cost and in a single day, and is therefore amenable to large-scale molecular screening of HI in North Africa.

Obesity is associated with significant disturbance in the hormonal milieu that can affect the reproductive system. Male infertility affects approximately 6% of reproductive-aged men. It has been suggested that overweight men or men with obese body mass index (BMI) experience prolonged time to pregnancy, although the influence of male BMI on fertility remains understudied. We hypothesised that BMI is inversely correlated with fertility, manifested by reduced sperm concentration and varicocele. Males of mean age 32.74 ± 6.96 years with semen analyses and self-reported BMI were included (n = 98). Patient parameters analysed included age, BMI, pubertal timing, the development of varicocele, and leutinizing hormone, follicle-stimulating hormone and testosterone (n = 18). The mean age of the study population was 32.74 ± 6.96 years. The incidence of azospermia, oligozoospermia, normospermia and the development of varicocele did not vary across BMI categories. Male obesity is not associated with the incidence of sperm concentration and the development of varicocele.

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