👤 Isis Arias

Late-onset Alzheimer's disease is a devastating and complex neurodegenerative disorder with a multifactorial etiology. Over the past decade, advances in genetic research have identified novel risk genes, shedding light on the underlying pathogenic mechanisms of late-onset Alzheimer's disease. This review provides a comprehensive overview of several of these crucial genetic factors and their potential mechanisms in the pathogenesis of Alzheimer's disease. Genome-wide association studies, whole-genome sequencing, and multi-omics studies have played a crucial role in identifying key risk genes, particularly those involved in amyloid-β metabolism and clearance, such as CLU and APOE, which influence amyloid-β aggregation. Tau pathology, characterized by neurofibrillary tangles, is another hallmark of Alzheimer's disease, with genes such as BIN1 implicated in tau-mediated neurodegeneration. Additionally, immune regulatory genes, including CR1, MS4A6A, CD33, and TREM2, play crucial roles in microglial activation and neuroinflammation, thereby contributing to disease progression. Synaptic dysfunction is also a critical factor in Alzheimer's disease pathology, with genes such as IQCK, EPHA1, and CD2AP linked to synaptic function and plasticity, highlighting their potential impact on cognitive decline. Understanding these genetic risk factors provides valuable insights into the complex genetic landscape of Alzheimer's disease and its highly heterogeneous pathological mechanisms, including amyloid-β metabolism, tau pathology, immune response and neuroinflammation, and synaptic dysfunction. Future research should focus on elucidating the functional roles of these individual genes and their potential as therapeutic targets for altering the course of Alzheimer's disease. Show less

Factors underlying discordant visual and quantitative amyloid beta-positron emission tomography (Aβ-PET) results and their clinical implications are not well understood. Participants from the 1Florida Alzheimer's Disease Research Center (1FLADRC) underwent Aβ-PET, blood draw, brain magnetic resonance imaging (MRI), and neuropsychological testing. We evaluated differences in demographics, apolipoprotein E ( We studied 386 participants (mean age ± SD: 70.7 ± 7.8, 55.2% female, 44.6% Hispanic White). Compared to V+/Q-, V-/Q+ had a higher frequency of Discordant Aβ-PET findings likely hold clinical significance and may reflect early stages of neuropathological progression. Groups with concordant/discordant visual-quantitative amyloid beta-positron emission tomography (Aβ-PET) results were compared.Visual-/quant+ were more likely than visual+/quant- to be apolipoprotein E ( Show less

Calorie restriction (CR; calorie intake reduced by ∼20%-40% below ad libitum, AL, intake) potentiates skeletal muscle insulin sensitivity during old age by incompletely understood mechanisms. We aimed to identify CR-induced changes in muscle insulin signaling that may explain this enhanced sensitivity. We examined how CR (65% of AL intake for 8-weeks) alters muscle insulin action and signaling in aged rats (24-month old) of both sexes. We assessed insulin-stimulated glucose uptake (ISGU) in muscle together with deep phosphoproteomic profiling. CR enhanced ISGU in both sexes, with higher ISGU in females regardless of diet. We identified 590 diet-responsive phosphosites, indicating extensive CR-induced remodelling of muscle phosphorylation, particularly within structural and contractile pathways. Strikingly, 70% of these sites were sex-specific. Numerous insulin-responsive sites were identified (193 in females; 107 in males) with 60 overlapping sites. The magnitude of the insulin-effects among all significantly regulated sites correlated between sexes. S1443 phosphorylation on EH domain-binding protein 1-like protein-1 (Ehbp1l1; a potential regulator of Rab proteins that control GLUT4 glucose transporter trafficking) was insulin-responsive in both sexes but only associated to ISGU in females. Personalized phosphoproteomic analysis also identified insulin-responsive sites on Leiomodin-1 (Lmod1) that correlated with ISGU across individuals. Both Lmod1 and Ehbp1l1 have strong genetic association with glycemic traits in humans, reinforcing their translational relevance. This study revealed sex-dependent and sex-independent phosphosignaling mechanisms that associate with muscle insulin responsiveness as well as hundreds of sex-specific, CR-responsive phosphosites. These findings provide a rich resource for future research on CR and insulin sensitivity. 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

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults, with a median overall survival (OS) of 15-18 months despite standard treatments. Approximately 8% of GBM cases exhibit genomic alterations in fibroblast growth factor receptors (FGFRs), particularly FGFR1 and FGFR3. Next-generation sequencing techniques have identified various FGFR3 fusions in GBM. This report presents a novel FGFR3 fusion with fatty acid synthase (FASN) in a 41-year-old male diagnosed with GBM. The patient presented with a persistent headache, and imaging revealed a right frontal lobe lesion. Surgical resection and subsequent histopathology confirmed GBM. Initial NGS analysis showed no mutations in the IDH1, IDH2 or H3F3 genes, but revealed a TERT promoter mutation and CDKN2A/2B and PTEN deletions. Postoperative treatment included radiotherapy and temozolomide. Despite initial management, recurrence occurred four months post-diagnosis, confirmed by MRI and histology. A second surgery identified a novel FGFR3-FASN fusion, alongside increased Ki67 expression. The recurrence was managed with regorafenib and bevacizumab, though complications like hand-foot syndrome and radiation necrosis arose. Despite initial improvement, the patient died 15 months after diagnosis. This case underscores the importance of understanding GBM's molecular landscape for effective treatment strategies. The novel FGFR3-FASN fusion suggests potential implications for GBM recurrence and lipid metabolism. Further studies are warranted to explore FGFR3-FASN's role in GBM and its therapeutic targeting. Show less

The effects of the consumption of high-fat diets (HFD) have been studied to unravel the molecular pathways they are altering in order to understand the link between increased caloric intake, metabolic diseases, and the risk of cognitive dysfunction. The saturated fatty acid, palmitic acid (PA), is the main component of HFD and it has been found increased in the circulation of obese and diabetic people. In the central nervous system, PA has been associated with inflammatory responses in astrocytes, but the effects on neurons exposed to it have not been largely investigated. Given that PA affects a variety of metabolic pathways, we aimed to analyze the transcriptomic profile activated by this fatty acid to shed light on the mechanisms of neuronal dysfunction. In the current study, we profiled the transcriptome response after PA exposition at non-toxic doses in primary hippocampal neurons. Gene ontology and Reactome pathway analysis revealed a pattern of gene expression which is associated with inflammatory pathways, and importantly, with the activation of lipid metabolism that is considered not very active in neurons. Validation by quantitative RT-PCR (qRT-PCR) of Hmgcs2, Angptl4, Ugt8, and Rnf145 support the results obtained by RNAseq. Overall, these findings suggest that neurons are able to respond to saturated fatty acids changing the expression pattern of genes associated with inflammatory response and lipid utilization that may be involved in the neuronal damage associated with metabolic diseases. Show less

Introduction: Obesity is considered a serious public health problem. Efforts have been directed to search for candidate genes such as LEP, LEPR, and MC4R involved in the leptin-melanocortin system. The neuroendocrine regulation of these genes on energy intake and balance influences the pathogenesis of this disease. Contradictory results regarding the association of these genes with obesity raise the need for new research. Objective: To analyze the association between obesity and LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms and the clinical and biochemical variables in obese adults from Barranquilla, Colombia. Materials and methods: We analyzed 111 obese adults and 155 non-obese individuals as controls. The polymorphisms were determined by real-time PCR. Besides, anthropometric measures, blood pressure, and biochemical tests were evaluated. Results: No statistical differences were found in allele and genotype frequencies of gene polymorphisms between groups. The CC genotype of MC4R rs17782313 polymorphism was associated with increased systolic blood pressure and T allele and TT genotype, with decreased HDL cholesterol in obese adults. The effect of the other polymorphisms on these variables was not evidenced. Conclusions: LEP rs2167270, LEPR rs1137101, and MC4R rs17782313 polymorphisms were not associated with obesity in the population under study. MC4R rs17782313 polymorphisms were associated with an increase in systolic blood pressure and a decrease in HDL cholesterol. Show less

CD5L (CD5 molecule-like) is a secreted glycoprotein that participates in host response to bacterial infection. CD5L influences the monocyte inflammatory response to the bacterial surface molecules lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by inhibiting TNF secretion. Here we studied the intracellular events that lead to macrophage TNF inhibition by human CD5L. To accomplish this goal, we performed functional analyses with human monocytic THP1 macrophages, as well as with peripheral blood monocytes. Inhibition of phosphatidylinositol 3-kinase (PtdIns3K) reversed the inhibitory effect of CD5L on TNF secretion. Among the various PtdIns3K isoforms, our results indicated that CD5L activates PtdIns3K (whose catalytic subunit is termed PIK3C3), a key modulator involved in autophagy. Further analysis revealed a concomitant enhancement of autophagy markers such as cellular LC3-II content, increased LC3 puncta, as well as LC3-LysoTracker Red colocalization. Moreover, electron microscopy showed an increased presence of cytosolic autophagosomes in THP1 macrophages overexpressing CD5L. Besides preventing TNF secretion, CD5L also inhibited IL1B and enhanced IL10 secretion. This macrophage anti-inflammatory pattern of CD5L was reverted upon silencing of autophagy protein ATG7 by siRNA transfection. Additional siRNA experiments in THP1 macrophages indicated that the induction of autophagy mechanisms by CD5L was achieved through cell-surface scavenger receptor CD36, a multiligand receptor expressed in a wide variety of cell types. Our data represent the first evidence that CD36 is involved in autophagy and point to a significant contribution of the CD5L-CD36 axis to the induction of macrophage autophagy. Show less