The NeuroinflammatoryPotential of HIV-1 NefVariants in Modulating the Gene Expression Profile of Astrocytes.

HIV-1 mediated neurotoxicity is thought to be associated with HIV-1 viral proteins activating astrocytes and microglia by inducing inflammatory cytokines leading to the development of HIV-associated neurocognitive disorder (HAND). In the current study, we observe how HIV-1 Nef upregulates the levels of IL-6, IP-10, and TNF-α around 6.0fold in normal human astrocytes (NHAs) compared to cell and empty vector controls. Moderate downregulation in the expression profile of inflammatory cytokines was observed due to RNA interference. Furthermore, we determine the impact of inflammatory cytokines in the upregulation of kynurenine pathway metabolites, such as indoleamine 2,3-dioxygenase (IDO), and 3-hydroxyanthranilic acid oxygenase (HAAO) in NHA, and found the same to be 3.0- and 3.2-fold, respectively. Additionally, the variation in the level of nitric oxide before and after RNA interference was significant. The upregulated cytokines and pathway-specific metabolites could be linked with the neurotoxic potential of HIV-1 Nef. Thus, the downregulation in cytokines and kynurenine metabolites observed after siRNA-Nef interference indicates the possibility of combining the RNA interference approach with current antiretroviral therapy to prevent neurotoxicity development.

3-Hydroxyanthralinic acid metabolism controls the hepatic SREBP/lipoprotein axis, inhibits inflammasome activation in macrophages, and decreases atherosclerosis in Ldlr-/- mice.

AIMS: Atherosclerosis is a chronic inflammatory disease involving immunological and metabolic processes. Metabolism of tryptophan (Trp) via the kynurenine pathway has shown immunomodulatory properties and the ability to modulate atherosclerosis. We identified 3-hydroxyanthranilic acid (3-HAA) as a key metabolite of Trp modulating vascular inflammation and lipid metabolism. The molecular mechanisms driven by 3-HAA in atherosclerosis have not been completely elucidated. In this study, we investigated whether two major signalling pathways, activation of SREBPs and inflammasome, are associated with the 3-HAA-dependent regulation of lipoprotein synthesis and inflammation in the atherogenesis process. Moreover, we examined whether inhibition of endogenous 3-HAA degradation affects hyperlipidaemia and plaque formation. METHODS AND RESULTS: In vitro, we showed that 3-HAA reduces SREBP-2 expression and nuclear translocation and apolipoprotein B secretion in HepG2 cell cultures, and inhibits inflammasome activation and IL-1ß production by macrophages. Using Ldlr-/- mice, we showed that inhibition of 3-HAA 3,4-dioxygenase (HAAO), which increases the endogenous levels of 3-HAA, decreases plasma lipids and atherosclerosis. Notably, HAAO inhibition led to decreased hepatic SREBP-2 mRNA levels and lipid accumulation, and improved liver pathology scores. CONCLUSIONS: We show that the activity of SREBP-2 and the inflammasome can be regulated by 3-HAA metabolism. Moreover, our study highlights that targeting HAAO is a promising strategy to prevent and treat hypercholesterolaemia and atherosclerosis.

Single Nucleotide Polymorphisms of HAAO and IRX6 Genes as Risk Factors for Hypospadias.

PURPOSE: We evaluated the association of hypospadias and 17 susceptibility loci previously identified by a European genome-wide association study in a cohort of Japanese patients. We also examined the expression of candidate genes in male mouse embryos to determine the possible underlying mechanisms of this disease. MATERIALS AND METHODS: We enrolled 169 Japanese patients (mean age at surgery 3.7 years) who underwent repair of hypospadias. Genotyping of 17 single nucleotide polymorphisms was performed using a multiplex polymerase chain reaction invader assay. We also performed in situ hybridization to determine whether candidate genes were expressed in the male genital tubercle during embryonic development of the external genitalia in mice. RESULTS: Single nucleotide polymorphism rs3816183 of HAAO was significantly associated with susceptibility to hypospadias in general (p = 0.0019) and to anterior/middle hypospadias (p = 0.0283) and posterior hypospadias (p = 0.0226), while single nucleotide polymorphism rs6499755 of IRX6 showed an association with susceptibility to anterior/middle hypospadias (p = 0.0472). In mouse embryos there was no significant upregulation of Haao expression in the developing male external genitalia. Irx3 and Irx5, which are linked to Irx6 within the IrxB cluster, were expressed in the mesenchyme remote from the urethral plate epithelium during the critical embryonic period for masculinization. Irx6 was expressed in the ectodermal epithelium, demonstrating prominent dorsal ectodermal expression without expression in the ventral ectoderm adjacent to the urethral plate during the same period. CONCLUSIONS: Genetic variations of HAAO and IRX6 influence susceptibility to hypospadias in the Japanese population. Further research is needed to clarify the mechanism by which variations in these genes contribute to the pathogenesis of hypospadias.