👤 Federico Salazar

Batten disease is characterized by early-onset blindness, juvenile dementia and death within the second decade of life. The most common genetic cause are mutations in CLN3, encoding a lysosomal protein. Currently, no therapies targeting disease progression are available, largely because its molecular mechanisms remain poorly understood. To understand how CLN3 loss affects cellular signaling, we generated human CLN3 knock-out cells (CLN3-KO) and performed RNA-seq analysis. Our multi-dimensional analysis reveals the transcriptional regulator YAP1 as a key factor in remodeling the transcriptome in CLN3-KO cells. YAP1-mediated pro-apoptotic signaling is also increased as a consequence of CLN3 functional loss in retinal pigment epithelia cells, and in the hippocampus and thalamus of Cln3 Show less

Lipoprotein(a) [Lp(a)] is a genetically determined and independent cardiovascular risk factor. Despite its clinical relevance, data on Lp(a) prevalence and impact in Latin America are limited. We aimed to assess the prevalence of elevated Lp(a) and its association with cardiovascular outcomes in a large, multicenter Argentine registry. The GAELp(a) registry included 3000 adults from six Argentine regions. Lp(a) levels were measured using standardized assays; elevated Lp(a) was defined as >50 mg/dL or >125 nmol/L. Clinical, biochemical, and imaging data were collected retrospectively and prospectively. Associations between Lp(a) and major adverse cardiovascular events (MACE) were evaluated with logistic regression in the overall population and stratified by statin use. Elevated Lp(a) was present in 31.4 % of participants, with no sex difference. It was associated with family history of cardiovascular disease, subclinical atherosclerosis, and familial hypercholesterolemia. Patients with elevated Lp(a) had a higher prevalence of coronary artery disease (18.4 % vs. 12.5 %, p < 0.001), peripheral artery disease (4.8 % vs. 2.5 %, p = 0.001), and MACE (21.3 % vs. 14.8 %, p < 0.001). Elevated Lp(a) independently predicted MACE (OR 1.53, 95 % CI: 1.24-1.90, p < 0.001), with stronger associations in statin-naïve individuals (OR 2.18, 95 % CI: 1.17-4.07). ROC analysis showed modest discrimination (AUC 0.57 in nmol/L, 0.59 in mg/dL). Elevated Lp(a) is frequent in Argentina and strongly linked to cardiovascular disease and events. Its predictive value appears greater in statin-naïve patients, highlighting its role as a marker of residual risk. These findings support routine Lp(a) measurement in cardiovascular risk assessment, particularly in regions with high ASCVD burden. Show less

Decades of research have produced extensive evidence of the contribution of genetic factors to the efficacy and toxicity of antipsychotics. Numerous genetic variants in genes controlling drug availability or involved in antipsychotic processes have been linked to treatment variability. The complex mechanism of action and multitarget profile of most antipsychotic drugs hinder the identification of pharmacogenetic markers of clinical value. Nevertheless, the validity of associations between variants in CYP1A2, CYP2D6, CYP2C19, ABCB1, DRD2, DRD3, HTR2A, HTR2C, BDNF, COMT, MC4R genes and antipsychotic response has been confirmed in independent candidate gene studies. Genome wide pharmacogenomic studies have proven the role of the glutamatergic pathway in mediating antipsychotic activity and have reported novel associations with antipsychotic response. However, only a limited number of the findings, mainly functional variants of CYP metabolic enzymes, have been shown to be of clinical utility and translated into useful pharmacogenetic markers. Based on the currently available information, actionable pharmacogenetics should be reduced to antipsychotics' dose adjustment according to the genetically predicted metabolic status (CYPs' profile) of the patient. Growing evidence suggests that such interventions will reduce antipsychotics' side-effects and increase treatment safety. Despite this evidence, the use of pharmacogenetics in psychiatric wards is minimal. Hopefully, further evidence on the clinical and economic benefits, the development of clinical protocols based on pharmacogenetic information, and improved and cheaper genetic testing will increase the implementation of pharmacogenetic guided prescription in clinical settings. Show less

Placental abruption (PA), a pregnancy-related vascular disorder, is a leading cause of maternal and perinatal morbidity and mortality. The success of identifying genetic susceptibility loci for PA, a multi-factorial heritable disorder, has been limited. We conducted a genome-wide association study (GWAS) and candidate gene association study using 470 PA cases and 473 controls from Lima, Peru. Genotyping for common genetic variations (single nucleotide polymorphisms, SNPs) was conducted using the Illumina Cardio-Metabo Chip platform. Common variations in 35 genes that participate in mitochondrial biogenesis (MB) and oxidative phosphorylation (OS) were selected for the candidate gene study. Regression models were fit to examine associations of each SNP with risk of PA. In pathway analyses, we examined functions and functional relationships of genes represented by the top GWAS hits. Genetic risk scores (GRS), based on top hits of the GWAS and candidate gene analyses, respectively, were computed using the risk allele counting method. The top hit in the GWAS analyses was rs1238566 (empirical P-value=1.04e-4 and FDR-adjusted P-value=5.65E-04) in FLI-1 gene, a megakaryocyte-specific transcription factor. Networks of genes involved in lipid metabolism and cell signaling were significantly enriched by the 51 genes whose SNPs were among the top 200 GWAS hits (P-value <2.1e-3). SNPs known to regulate MB (e.g. CAMK2B, NR1H3, PPARG, PRKCA, and THRB) and OP (e.g., COX5A, and NDUF family of genes) were associated with PA risk (P-value <0.05). GRS was significantly associated with PA risk (trend P-value <0.001 and 0.01 for GWAS and candidate gene based GRS, respectively). Our study suggests that integrating multiple analytical strategies in genetic association studies can provide opportunities for identifying genetic risk factors and novel molecular mechanisms that underlie PA. Show less

The liver X receptor (LXR) signaling pathway is an important modulator of atherosclerosis, but the relative importance of the two LXRs in atheroprotection is incompletely understood. We show here that LXRα, the dominant LXR isotype expressed in liver, plays a particularly important role in whole-body sterol homeostasis. In the context of the ApoE(-/-) background, deletion of LXRα, but not LXRβ, led to prominent increases in atherosclerosis and peripheral cholesterol accumulation. However, combined loss of LXRα and LXRβ on the ApoE(-/-) background led to an even more severe cholesterol accumulation phenotype compared to LXRα(-/-)ApoE(-/-) mice, indicating that LXRβ does contribute to reverse cholesterol transport (RCT) but that this contribution is quantitatively less important than that of LXRα. Unexpectedly, macrophages did not appear to underlie the differential phenotype of LXRα(-/-)ApoE(-/-) and LXRβ(-/-)ApoE(-/-) mice, as in vitro assays revealed no difference in the efficiency of cholesterol efflux from isolated macrophages. By contrast, in vivo assays of RCT using exogenously labeled macrophages revealed a marked defect in fecal sterol efflux in LXRα(-/-)ApoE(-/-) mice. Mechanistically, this defect was linked to a specific requirement for LXRα(-/-) in the expression of hepatic LXR target genes involved in sterol transport and metabolism. These studies reveal a previously unrecognized requirement for hepatic LXRα for optimal reverse cholesterol transport in mice. Show less

The most relevant clinical phenotype resulting from chronic enteroviral myocarditis is dilated cardiomyopathy (DCM). Mice of the susceptible mouse strain A.BY/SnJ mimick well human DCM since they develop as a consequence of persistent infection and chronic inflammation a dilation of the heart ventricle several weeks after coxsackievirus B3 (CVB3) infection. Therefore, this model is well suited for the analysis of changes in the heart proteome associated with DCM. Here, we present a proteomic survey of the dilated hearts based on differential fluorescence gel electrophoresis and liquid chromatography-mass spectrometric centered methods in comparison to age-matched non-infected hearts. In total, 101 distinct proteins, which belong to categories immunity and defense, cell structure and associated proteins, energy metabolism and protein metabolism/modification differed in their levels in both groups. Levels of proteins involved in fatty acid metabolism and electron transport chain were found to be significantly reduced in infected mice suggesting a decrease in energy production in CVB3-induced DCM. Furthermore, proteins associated with muscle contraction (MLRV, MLRc2, MYH6, MyBPC3), were present in significantly altered amounts in infected mice. A significant increase in the level of extracellular matrix proteins in the dilated hearts indicates cardiac remodeling due to fibrosis. Show less

Ligand activation of liver X receptors (LXRs) has been shown to impact both lipid metabolism and inflammation. One complicating factor in studies utilizing synthetic LXR agonists is the potential for pharmacologic and receptor-independent effects. Here, we describe an LXR gain-of-function system that does not depend on the addition of exogenous ligand. We generated transgenic mice expressing a constitutively active VP16-LXRα protein from the aP2 promoter. These mice exhibit increased LXR signaling selectively in adipose and macrophages. Analysis of gene expression in primary macrophages derived from two independent VP16-LXRα transgenic lines confirmed the ability of LXR to drive expression of genes involved in cholesterol efflux and fatty acid synthesis. Moreover, VP16-LXRα expression also suppressed the induction of inflammatory genes by lipopolysaccharide to a comparable degree as synthetic agonist. We further utilized VP16-LXRα-expressing macrophages to identify and validate new targets for LXRs, including the gene encoding ADP-ribosylation factor-like 7 (ARL7). ARL7 has previously been shown to transport cholesterol to the membrane for ABCA1-associated removal and thus may be integral to the LXR-dependent efflux pathway. We show that the ARL7 promoter contains a functional LXRE and can be transactivated by LXRs in a sequence-specific manner, indicating that ARL7 is a direct target of LXR. These findings provide further support for an important role of LXRs in the coordinated regulation of lipid metabolic and inflammatory gene programs in macrophages. Show less

Hyperlipidemia associated with the protease inhibitor (PI) component of highly active antiretrovial treatment can lead to accelerated atherosclerosis. The apolipoprotein A-V (APOA5) gene, which affects VLDL production and lipolysis, may play a role in PI-induced hyperlipidemia, particularly in individuals with the APOA5-1131T-->C genotype. We measured lipoprotein changes in HIV-positive patients (n = 229) who had been followed for 5 years. For statistical analyses, we segregated the patients with respect to PI treatment and APOA5-1131T-->C genotype. The frequency of the C allele was 0.08, similar to that in the general population. We found a strong effect of the APOA5-1131T-->C genotype among patients receiving PIs. Carriers of the C allele had consistently increased mean (SD) triglyceride concentrations compared with noncarriers after 1 year [2.11 (1.62) vs 3.71 (4.27) mmol/L; P = 0.009], 2 years [2.48 (2.09) vs 4.02 (4.05) mmol/L, P = 0.050], 3 years [2.32 (1.71) vs 4.13 (4.26) mmol/L; P = 0.013], 4 years [2.90 (2.95) vs 5.35 (7.12) mmol/L; P was not significant], and 5 years [4.25 (5.58) vs 9.23 (9.63) mmol/L; P was not significant]. We observed the same effect on total cholesterol concentrations: after 1 year [4.93 (1.31) vs 5.87 (1.66) mmol/L; P = 0.006], 2 years [5.03 (1.12) vs 6.42 (2.48) mmol/L; P = 0.001], 3 years [5.11 (1.17) vs 6.38 (2.43) mmol/L; P = 0.009], 4 years [5.49 (1.71) vs 6.78 (3.03) mmol/L; P was not significant], and 5 years [5.56 (1.75) vs 7.90 (3.60) mmol/L; P was not significant]. HDL cholesterol showed a progressive reduction, leading to a considerably higher cholesterol/HDL cholesterol ratio after 3 years. Variability in the APOA5 gene predisposes patients with HIV, particularly those treated with PI, to severe hyperlipidemia. Show less

The newly recognised apolipoprotein (apo) AV gene (APOAV) has been linked to fasting plasma triglyceride (TG) concentrations with some polymorphisms associated with elevated fasting TGs. Since fasting plasma TGs are mainly determined by the hepatic production of TG-rich particles (very low density lipoprotein; VLDL), and fasting TGs are the major determinants of postprandial lipaemia, we have evaluated the effects of an APOAV polymorphism on postprandial triglyceridaemia, which is largely determined by the intestinal production and clearance of chylomicrons. For this purpose, diurnal capillary triglyceridaemia (reflecting postprandial lipaemia) was determined in a cohort of 88 healthy volunteers (48 males and 40 females) in relation with a -1131T>C variant in the promoter of APOAV. Thirteen of these subjects (7 males and 6 females) were carriers of the -1131C allele, which has been associated with higher fasting plasma TG levels. The carriers had higher fasting capillary TG concentrations, although plasma TGs were not significantly different from non-carriers in this cohort. Surprisingly, total diurnal triglyceridaemia calculated as the area under the capillary TG curve was similar in carriers compared to non-carriers but after correction for fasting capillary TG levels, incremental diurnal triglyceridaemia was significantly lower in carriers (1.74 (5.27) mmol/h/l) than in non-carriers (4.91 (4.90) mmol/h/l; p = 0.036). The same trends were found for both males and females when analysed separately. Since dietary intake, which is a major determinant of incremental diurnal triglyceridaemia, did not differ between the two groups, we believe that these differences are at least partly explained by the APOAV. In summary, the APOAV assessed by means of the -1131T>C variant seemed to have a paradoxical effect on postprandial lipaemia when compared to fasting TG levels. Show less