Two Functional Variants of IRF5 Influence the Development of Macular Edema in Patients with Non-Anterior Uveitis

Objective

Interferon (IFN) signaling plays a crucial role in autoimmunity. Genetic variation in interferon regulatory factor 5 (IRF5), a major regulator of the type I interferon induction, has been associated with risk of developing several autoimmune diseases. In the current study we aimed to evaluate whether three sets of correlated IRF5 genetic variants, independently associated with SLE and with different functional roles, are involved in uveitis susceptibility and its clinical subphenotypes.

Methods

Three IRF5 polymorphisms, rs2004640, rs2070197 and rs10954213, representative of each group, were genotyped using TaqMan® allelic discrimination assays in a total of 263 non-anterior uveitis patients and 724 healthy controls of Spanish origin.

Results

A clear association between two of the three analyzed genetic variants, rs2004640 and rs10954213, and the absence of macular edema was observed in the case/control analysis (P _FDR=5.07E-03, OR=1.48, CI 95%=1.14-1.92 and P _FDR=3.37E-03, OR=1.54, CI 95%=1.19-2.01, respectively). Consistently, the subphenotype analysis accordingly with the presence/absence of this clinical condition also reached statistical significance (rs2004640: P=0.037, OR=0.69, CI 95%=0.48-0.98; rs10954213: P=0.030, OR=0.67, CI 95%=0.47-0.96), thus suggesting that both IRF5 genetic variants are specifically associated with the lack of macular edema in uveitis patients.

Conclusion

Our results clearly showed for the first time that two functional genetic variants of IRF5 may play a role in the development of macular edema in non-anterior uveitis patients. Identifying genetic markers for macular edema could lead to the possibility of developing novel treatments or preventive therapies.     

Potent antimalarial 4-pyridones with improved physico-chemical properties

Antimalarial 4-pyridones are a novel class of inhibitors of the plasmodial mitochondrial electron transport chain targeting Cytochrome bc1 (complex III). In general, the most potent 4-pyridones are lipophilic molecules with poor solubility in aqueous media and low oral bioavailability in pre-clinical species from the solid dosage form. The strategy of introducing polar hydroxymethyl groups has enabled us to maintain the high levels of antimalarial potency observed for other more lipophilic analogues whilst improving the solubility and the oral bioavailability in pre-clinical species.     

P2Y purinergic regulation of the glycine neurotransmitter transporters

The sodium- and chloride-coupled glycine neurotransmitter transporters (GLYTs) control the availability of glycine at glycine-mediated synapses. The mainly glial GLYT1 is the key regulator of the glycine levels in glycinergic and glutamatergic pathways, whereas the neuronal GLYT2 is involved in the recycling of synaptic glycine from the inhibitory synaptic cleft. In this study, we report that stimulation of P2Y purinergic receptors with 2-methylthioadenosine 5'-diphosphate in rat brainstem/spinal cord primary neuronal cultures and adult rat synaptosomes leads to the inhibition of GLYT2 and the stimulation of GLYT1 by a paracrine regulation. These effects are mainly mediated by the ADP-preferring subtypes P2Y(1) and P2Y(13) because the effects are partially reversed by the specific antagonists N(6)-methyl-2'-deoxyadenosine-3',5'-bisphosphate and pyridoxal-5'-phosphate-6-azo(2-chloro-5-nitrophenyl)-2,4-disulfonate and are totally blocked by suramin. P2Y(12) receptor is additionally involved in GLYT1 stimulation. Using pharmacological approaches and siRNA-mediated protein knockdown methodology, we elucidate the molecular mechanisms of GLYT regulation. Modulation takes place through a signaling cascade involving phospholipase C activation, inositol 1,4,5-trisphosphate production, intracellular Ca(2+) mobilization, protein kinase C stimulation, nitric oxide formation, cyclic guanosine monophosphate production, and protein kinase G-I (PKG-I) activation. GLYT1 and GLYT2 are differentially sensitive to NO/cGMP/PKG-I both in brain-derived preparations and in heterologous systems expressing the recombinant transporters and P2Y(1) receptor. Sensitivity to 2-methylthioadenosine 5'-diphosphate by GLYT1 and GLYT2 was abolished by small interfering RNA (siRNA)-mediated knockdown of nitric-oxide synthase. Our data may help define the role of GLYTs in nociception and pain sensitization.     

Subcellular localization and role of lipin-1 in human macrophages

The lipins have been described as metabolic enzymes that regulate lipid biosynthesis and also signaling processes by controlling the cellular concentration of bioactive lipids, phosphatidic acid, and diacylgycerol. In the present work we have studied the subcellular localization and role of lipin-1 in human monocyte-derived macrophages. Human macrophages express lipin-1 isoforms α and β. A transfected lipin-1α-enhanced GFP construct associates with membranes of cellular organelles that can be stained with Nile Red. Colocalization experiments with lipid droplet (LD)-specific proteins such as adipophilin/adipose differentiation-related protein/perilipin 2 or TIP47/perilipin 3 show that both proteins colocalize with lipin-1α in the same cellular structures. Reduction of the expression levels of lipin-1 by small interfering RNA technology does not impair triacylglycerol biosynthesis but reduces the size of LDs formed in response to oleic acid. In agreement with these data, peritoneal macrophages from animals that carry a mutation in the Lpin-1 gene (fld animals) also produce less and smaller LDs in response to oleic acid. Mass spectrometry determinations demonstrate that the fatty acid composition of triacylglycerol in isolated LDs from lipin-1-deficient cells differs from that of control cells. Moreover, activation of cytosolic group IVA phospholipase A(2)α, a proinflammatory enzyme that is also involved in LD biogenesis, is also compromised in lipin-1-deficient cells. Collectively, these data suggest that lipin-1 associates with LDs and regulates the activation of cytosolic group IVA phospholipase A(2)α in human monocyte-derived macrophages.     

Effect of ICSI and embryo biopsy on embryo development and apoptosis according to oocyte diameter in prepubertal goats

ICSI and embryo biopsy are routine methods used for assisted reproduction. However, their impact on embryo quality is still poor studied. Moreover, oocyte size is also a crucial factor for blastocyst production. In this study effect of oocyte size, ICSI and embryo biopsy was assessed in terms of incidence of apoptosis and blastocyst development. IVM-oocytes from prepubertal goats were fertilized by ICSI or IVF. Embryos obtained were divided depending on oocyte size, biopsied at day-4 post-insemination/injection and cultured for additional 4-5 days. Apoptotic cell number was assessed by TUNEL staining in day-4 embryos and blastocysts obtained. In each diameter group, ICSI did not affect embryo development, blastocyst cell number and embryo apoptotic grade in comparison to IVF. Embryo biopsy did not affect blastocyst rate and apoptotic cell number, but decreased blastocyst cell number (P=0.0018). Moreover, there was a negative relationship between blastocyst cell number and apoptotic grade (P<0.05). In conclusion, ICSI and embryo biopsy do not have negative effect on embryo quality and development. However, oocyte size has a positive relationship on blastocyst yield and quality.     

Transforming growth factor-beta1 decreases cardiac muscle L-type Ca2+ current and charge movement by acting on the Cav1.2 mRNA

Transforming growth factors-beta (TGF-betas) are essential to the structural remodeling seen in cardiac disease and development; however, little is known about potential electrophysiological effects. We hypothesized that chronic exposure (6-48 h) of primary cultured neonatal rat cardiomyocytes to the type 1 TGF-beta (TGF-beta1, 5 ng/ml) may affect voltage-dependent Ca(2+) channels. Thus we investigated T- (I(CaT)) and L-type (I(CaL)) Ca(2+) currents, as well as dihydropyridine-sensitive charge movement using the whole cell patch-clamp technique and quantified Ca(V)1.2 mRNA levels by real-time PCR assay. In ventricular myocytes, TGF-beta1 did not exert significant electrophysiological effects. However, in atrial myocytes, TGF-beta1 reduced both I(CaL) and charge movement (55% at 24-48 h) without significantly altering I(CaT), cell membrane capacitance, or channel kinetics (voltage dependence of activation and inactivation, as well as the activation and inactivation rates). Reductions of I(CaL) and charge movement were explained by concomitant effects on the maximal values of L-channels conductance (G(max)) and charge movement (Q(max)). Thus TGF-beta1 selectively reduces the number of functional L-channels on the surface of the plasma membrane in atrial but not ventricular myocytes. The TGF-beta1-induced I(CaL) reduction was unaffected by supplementing intracellular recording solutions with okadaic acid (2 microM) or cAMP (100 microM), two compounds that promote L-channel phosphorylation. This suggests that the decreased number of functional L-channels cannot be explained by a possible regulation in the L-channels phosphorylation state. Instead, we found that TGF-beta1 decreases the expression levels of atrial Ca(V)1.2 mRNA (70%). Thus TGF-beta1 downregulates atrial L-channel expression and may be therefore contributing to the in vivo cardiac electrical remodeling.     

Inactivation of the nodH gene in Sinorhizobium sp. BR816 enhances symbiosis with Phaseolus vulgaris L

Sulfate modification on Rhizobium Nod factor signaling molecules is not a prerequisite for successful symbiosis with the common bean (Phaseolus vulgaris L.). However, many bean-nodulating rhizobia, including the broad host strain Sinorhizobium sp. BR816, produce sulfated Nod factors. Here, we show that the nodH gene, encoding a sulfotransferase, is responsible for the transfer of sulfate to the Nod factor backbone in Sinorhizobium sp. BR816, as was shown for other rhizobia. Interestingly, inactivation of nodH enables inoculated bean plants to fix significantly more nitrogen under different experimental setups. Our studies show that nodH in the wild-type strain is still expressed during the later stages of symbiosis. This is the first report on enhanced nitrogen fixation by blocking Nod factor sulfation.