The role of a functional variant of TYK2 in vasculitides and infections.

OBJECTIVES: The TYK2 gene encodes a tyrosin kinase which is involved in multiple immune functions. A functional variant of this gene has been identified to play a protective role in multiple autoimmune diseases. The goal of this study was to evaluate the involvement of this variant of TYK2 in vasculitides [giant cell arteritis (GCA), ANCA-associated vasculitis (AAV) and IgA vasculitis (IgAV)] and viral infections [hepatitis C virus (HCV) and human immunodeficiency virus type I (HIV-1)]. METHODS: The study sample was composed of 13,745 European individuals. The genotyping was performed by Immunochip and TaqMan 5' allele discrimination assays and the allele frequencies were compared using PLINK. RESULTS: Although the results obtained did not reach the genome-wide level of significance, p-values at nominal significance were observed, suggesting that the TYK2 variant provides protection against two vasculitides: GCA (p=5.94E-3; OR (95%CI) = 0.56 (0.37-0.85) and AAV (p=6.79E-3; OR (95%CI) = 0.65 (0.47-0.89). However, this variant was not found to be associated with IgAV. No evidence was gained that the TYK2 variant confers susceptibility to HCV and HIV-1 infection. CONCLUSIONS: This is the first study to propose the association between the TYK2 and both GCA and AAV. Our findings also suggest that TYK2 does not play a relevant role in IgAV or in susceptibility to HCV and HVI-1.

Pattern and density of vascularization in mammalian testes, ovaries, and ovotestes.

According to the classical paradigm, the vasculature of the embryonic testis is more dense and complex than that of the ovary, but recent studies based on whole-mount detection of Caveolin-1 (CAV1) as an endothelial cell marker, have suggested that the level of ovarian vascularization is higher than previously assumed. However, this new hypothesis has been neither tested using alternative methodology nor investigated in other mammalian species. In this paper, we have studied the vascularization process in the gonads of males and females of two mammalian species, the mouse (Mus musculus) and the Iberian mole (Talpa occidentalis). Our results show that the pattern of testis vascularization is very well conserved among mammals, including both pre- and postnatal stages of development and, at least in the mole, it is conserved irrespectively of whether the testicular tissue is XY or XX. We have shown that CAV1 is present not only in endothelial cells but also in prefollicular oocytes and in an ovarian population of somatic cortical cells. These data clearly establish that: (1) according to the classical hypothesis, the degree of vascularization of the developing ovary is lower than that of the testis, (2) ovarian vascularization is also evolutionarily conserved as it occurs similarly both in moles and in mice, and (3) that the degree of vascular development of the mammalian ovary is age-dependent increasing significatively at puberty. The expression of CAV1 in the ovary of most animal taxa, from nematodes to mammals, strongly suggests a role for this gene in the female meiosis.

Polymorphisms in the interleukin 4, interleukin 13, and corresponding receptor genes are not associated with systemic sclerosis and do not influence gene expression.

OBJECTIVE: Polymorphisms in the genes encoding interleukin 4 (IL4), interleukin 13 (IL13), and their corresponding receptors have been associated with multiple immune-mediated diseases. Our aim was to validate these previous observations in patients with systemic sclerosis (SSc) and scrutinize the effect of the polymorphisms on gene expression in various populations of peripheral blood leukocytes. METHODS: We genotyped a cohort of 2488 patients with SSc and 2246 healthy controls from The Netherlands, Spain, United Kingdom, Italy, Germany, and France. Taqman assays were used to genotype single-nucleotide polymorphisms (SNP) in the following genes: (1) IL4 (-590C>T/rs2243250); (2) IL4 receptor alpha (IL4RA) (Q576R/rs1801275); (3) IL13 (R130Q/rs20541 and -1112C>T/rs1800925); and (4) IL13RA1 (43163G>A/rs6646259). The effect of these polymorphisms on expression of the corresponding genes was assessed using quantitative RT-PCR on RNA derived from peripheral blood B cells, T cells, plasmacytoid dendritic cells, monocytes, and myeloid dendritic cells. We investigated whether these polymorphisms influenced development of pulmonary complications over 15 years in patients with SSc. RESULTS: None of the investigated polymorphisms was associated with SSc or any SSc clinical subtype. We did not observe any effect on transcript levels in the cell subtypes or on development of pulmonary complications. CONCLUSION: Our data showed that polymorphisms in IL4, IL13, and their receptors do not play a role in SSc and do not influence the expression of their corresponding transcript in peripheral blood cells.

Role of rs1343151 IL23R and rs3790567 IL12RB2 polymorphisms in biopsy-proven giant cell arteritis.

OBJECTIVE: To assess the potential association between the rs1343151 IL23R and the rs3790567 IL12RB2 polymorphisms and giant cell arteritis (GCA). We also studied whether these polymorphisms might influence the phenotypic expression of GCA. METHODS: In total, 357 Spanish patients with biopsy-proven GCA and 574 matched controls were assessed. DNA from patients and controls was obtained from peripheral blood. Samples were genotyped for the rs1343151 IL23R and the rs3790567 IL12RB2 polymorphisms using a predesigned TaqMan allele discrimination assay and by polymerase chain reaction amplification. RESULTS: Regarding the rs1343151 IL23R polymorphism, no significant differences in the genotype or allele frequencies between GCA patients and healthy controls were observed. The frequency of the minor allele A of the rs3790567 IL12RB2 variant was increased in GCA patients compared with controls (30.1% vs 25.7%, respectively; p = 0.039, OR 1.25, 95% CI 1.01-1.54). An increased frequency of subjects carrying the minor allele A (GA+AA genotypes) of the rs3790567 IL12RB2 polymorphism was found among GCA patients compared with controls (52.8% vs 44.4%; p = 0.013, OR 1.40, 95% CI 1.06-1.85). Although a higher frequency of the combination of minor alleles (A-A) in the subgroup of patients with visual ischemic complications compared with the combination of both major alleles (G-G; p = 0.029) or with the other allelic combinations (p = 0.035) was found, logistic regression analysis showed that this association was no longer significant after adjustment for potential confounding factors (A-A vs G-G: OR 2.10, 95% CI 0.88-5.04, p = 0.096). CONCLUSION: Our results support a potential influence of the rs3790567 IL12RB2 polymorphism in the pathogenesis of GCA.

The spatio-temporal pattern of testis organogenesis in mammals - insights from the mole.

Some cellular events are crucial in testis organogenesis, including Sertoli and Leydig cell differentiation, mesonephric cell migration and testis cord formation. These processes are controlled by transcription factors, paracrine signalling and hormones. Using the mole species Talpa occidentalis as an alternative animal model, we report the expression patterns of nine genes during testis differentiation and analyse their implications in the above-mentioned cellular processes. We show that: 1) Sertoli cell differentiation occurs very early and precedes mesonephric cell migration, indicating that the latter is not needed for the endocrine cytodifferentiation of Sertoli cells; 2) the time of Leydig cell differentiation is consistent with the participation of PDGFR-alpha in promoting the migration and/or proliferation of Leydig cell precursors, and with that of WNT4 signalling in inhibiting Leydig cell differentiation and 3) the formation of the tunica albuginea involves intragonadal cell migration/movement. These results demonstrate that testicular organogenesis in the mole differs from that in the mouse in some particular aspects, thus providing evidence that the spatio-temporal pattern of testis development is not highly conserved during mammalian evolution.