👤 Vítor Santos

Disease-modifying therapies (DMT) for Alzheimer's disease (AD) are highly longed-for. In this quest, anti-amyloid therapies take center stage supported by genetic facts that highlight an imbalance between production and clearance of amyloid-β peptide (Aβ) in AD patients. Indeed, evidence from basic research, human genetic and biomarker studies, suggests the accumulation of Aβ as a driver of AD pathogenesis and progression. The aspartic protease β-site AβPP cleaving enzyme (BACE1) is the initiator for Aβ production. Underpinning a critical role for BACE1 in AD pathophysiology are the elevated BACE1 concentration and activity observed in the brain and body fluids of AD patients. Therefore, BACE1 is a prime drug target for reducing Aβ levels in early AD. Small-molecule BACE1 inhibitors have been extensively developed for the last 20 years. However, clinical trials with these molecules have been discontinued for futility or safety reasons. Most of the observed adverse side effects were due to other aspartic proteases cross-inhibition, including the homologue BACE2, and to mechanism-based toxicity since BACE1 has substrates with important roles for synaptic plasticity and synaptic homeostasis besides amyloid-β protein precursor (AβPP). Despite these setbacks, BACE1 persists as a well-validated therapeutic target for which a specific inhibitor with high substrate selectivity may yet to be found. In this review we provide an overview of the evolution in BACE1 inhibitors design pinpointing the molecules that reached advanced phases of clinical trials and the liabilities that precluded adequate trial effects. Finally, we ponder on the challenges that anti-amyloid therapies must overcome to achieve clinical success. Show less

Glioblastoma is a highly aggressive brain tumour that creates an immunosuppressive microenvironment. Microglia, the brain's resident immune cells, play a crucial role in this environment. Glioblastoma cells can reprogramme microglia to create a supportive niche that promotes tumour growth. However, the mechanisms controlling the acquisition of a transcriptome associated with a tumour-supportive microglial reactive state are not fully understood. In this study, we investigated changes in the transcriptional profile of BV2 microglia exposed to C6 glioma cells. RNA-sequencing analysis revealed a significant upregulation of microglial inhibitor of DNA binding 1 (Id1) and Id2, helix-loop-helix negative transcription regulatory factors. The concomitant regulation of microglial ETS proto-oncogene 2, transcription factor (ETS2)-target genes, i.e., Dusp6, Fli1, Jun, Hmox1, and Stab1, led us to hypothesize that ETS2 could be regulated by ID proteins. In fact, ID2-ETS2 protein interactions increased in microglia exposed to glioma cells. In addition, perturbation of the ID2-ETS2 transcriptional axis influenced the acquisition of a microglial tumour-supportive phenotype. ID2 and ETS2 genes were found to be expressed by the tumour-associated microglia isolated from human glioblastoma tumour biopsies. Furthermore, ID2 and ETS2 gene expressions exhibited inverse prognostic values in patients with glioma in cohorts from The Cancer Genome Atlas. Collectively, our findings indicate that the regulation of ETS2 by ID2 plays a role in the transcriptional regulation of microglia in response to stimuli originating from glioblastoma cells, information that could lead to developing therapeutic strategies to manipulate microglial tumour-trophic functions. Show less

Interleukin 27 (IL-27) is a cytokine that regulates susceptibility to Leishmania infantum infection in humans and experimental models. This cytokine has not yet been described in canine leishmaniasis (CanL). Therefore, we investigated whether IL-27 has a regulatory role in CanL. The EBI3 and p28 subunits of IL-27 were measured in splenic leukocytes culture supernatant from dogs with CanL and compared to control dogs. We also correlated EBI3 and p28 levels with IL-21, anti-L. infantum antibodies and parasite loads. We performed functional assays followed by IL-27 blockade and measured parasite loads, production of cytokines in splenic leukocytes culture supernatant, and the expression of PD-1, CTLA-4, phospho-Stat-1/3, T-bet, GATA3 and nitric oxide production (NO). Both IL-27 subunits increased in the supernatant of dogs with CanL compared to control dogs. EBI3 and p28 levels showed a moderate positive correlation with IL-21 (r = 0.67, p < 0.0001 and r = 0.45, p < 0.012, respectively), and the EBI3 subunit was positively associated with anti-L. infantum IgG antibodies (r = 0.38, p < 0.040) and parasite load (r = 0.47, p < 0.009). IL-27 and IL-21 participate of immune responses in CanL. IL-27 may be associated with the failure of immunity to control parasite replication via upregulation of the expression of PD-1, CTLA-4, T-bet and NO in splenic leukocytes from dogs with CanL. These findings suggest that the pathways regulated by IL-27 are involved in CanL pathogenesis in the host, and may be targets for new therapies. Show less

Chimeric antigen receptor (CAR) engineering of natural killer (NK) cells has shown promising results in early-phase clinical studies. However, advancing CAR-NK cell therapeutic efficacy is imperative. In this study, we investigated the impact of a fourth-generation CD19-targeted CAR (CAR.19) coexpressing IL-27 on NK-92 cells. We observed a significant improvement in NK-92 cell proliferation and cytotoxicity activity against B-cell cancer cell lines, both in vitro and in a xenograft mouse B-cell lymphoma model. Our systematic transcriptome analysis of the activated NK-92 CAR variants further supports the potential of IL-27 in fourth-generation CARs to overcome limitations of NK cell-based targeted tumor therapies by providing essential growth and activation signals. Integrating IL-27 into CAR-NK cells emerges as a promising strategy to enhance their therapeutic potential and elicit robust responses against cancer cells. These findings contribute substantially to the mounting evidence supporting the potential of fourth-generation CAR engineering in advancing NK cell-based immunotherapies. Show less

Dimethyl fumarate (DMF, Tecfidera) is an oral drug utilized to treat relapsing-remitting multiple sclerosis (MS). DMF treatment reduces disease activity in MS. Gastrointestinal discomfort is a common adverse effect of the treatment with DMF. This study aimed to investigate the effect of DMF administration in the gut draining lymph nodes cells of C57BL6/J female mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We have demonstrated that the treatment with DMF (7.5 mg/kg) significantly reduces the severity of EAE. This reduction of the severity is accompanied by the increase of both proinflammatory and anti-inflammatory mechanisms at the beginning of the treatment. As the treatment progressed, we observed an increasing number of regulatory Foxp3 negative CD4 T cells (Tr1), and anti-inflammatory cytokines such as IL-27, as well as the reduction of PGE2 level in the mesenteric lymph nodes of mice with EAE. We provide evidence that DMF induces a gradual anti-inflammatory response in the gut draining lymph nodes, which might contribute to the reduction of both intestinal discomfort and the inflammatory response of EAE. These findings indicate that the gut is the first microenvironment of action of DMF, which may contribute to its effects of reducing disease severity in MS patients. Show less

Cross-language studies suggest more similarities than differences in how dysarthria affects the speech of people with Parkinson's disease (PwPD) who speak different languages. In this study, we aimed to identify the relative contribution of acoustic variables to distinguish PwPD from controls who spoke varieties of two Romance languages, French and Portuguese. This bi-national, cross-sectional, and case-controlled study included 129 PwPD and 124 healthy controls who spoke French or Portuguese. All participants underwent the same clinical examinations, voice/speech recordings, and self-assessment questionnaires. PwPD were evaluated French-speaking and Portuguese-speaking individuals were distinguished from each other with over 90% accuracy by five acoustic variables (the mean fundamental frequency and the shimmer of the sustained vowel /a/ production, the oral diadochokinesis performance index, the relative sound level pressure and the relative sound pressure level standard deviation of the text reading). A distinct set of parameters discriminated between controls and PwPD: for men, maximum phonation time and the oral diadochokinesis speech proportion were the most significant variables; for women, variables calculated from the oral diadochokinesis were the most discriminative. Acoustic variables related to phonation and voice quality distinguished between speakers of the two languages. Variables related to pneumophonic coordination and articulation rate were the more effective in distinguishing PwPD from controls. Thus, our research findings support that respiration and diadochokinesis tasks appear to be the most appropriate to pinpoint signs of dysarthria, which are largely homogeneous and language-universal. In contrast, identifying language-specific variables with the speech tasks and acoustic variables studied was less conclusive. Show less

A malfunction in the melanocortin-4 receptor (MC4R) is associated with obesity in rare genetic syndromes; setmelanotide is a new drug that activates this receptor and is being used to treat severe obesity. This meta-analysis evaluated the efficacy and safety of setmelanotide for weight loss in severe obesity linked to human MC4R deficiency. We searched PubMed, Embase, and Cochrane for randomized and nonrandomized clinical trials using setmelanotide. We considered a We included 376 patients, of whom 328 (87.2%) received setmelanotide for a mean follow-up of 52 weeks. The mean age was 32.8 (14.67) years. Weight loss was significant (MD -3.52; 95% CI -3.98, -3.05; Our results support the use of setmelanotide in treating severe obesity. Show less

Polymorphisms in genes of leptin-melanocortin and insulin pathways have been associated with obesity and type 2 diabetes. We hypothesized that polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory markers and food intake composition in Brazilian subjects. This exploratory pilot study included 358 adult subjects. Clinical, anthropometric, and laboratory data were obtained through interview and access to medical records. The variants IRS1 rs2943634 A˃C, IRS2 rs1865434 C>T, MC3R rs3746619 C>A, and MC4R rs17782313 T>C were analyzed by real-time polymerase chain reaction. Food intake composition was assessed in a group of subjects with obesity (n = 84) before and after a short-term nutritional counseling program (9 weeks). MC4R rs17782313 was associated with increased risk of obesity (P = .034). Multivariate linear regression analysis adjusted by covariates indicated associations of IRS2 rs1865434 with reduced low-density lipoprotein cholesterol and resistin, MC3R rs3746619 with high glycated hemoglobin, and IRS1 rs2943634 and MC4R rs17782313 with increased high-sensitivity C-reactive protein (P < .05). Energy intake and carbohydrate and total fat intakes were reduced after the diet-oriented program (P < .05). Multivariate linear regression analysis showed associations of IRS2 rs1865434 with high basal fiber intake, IRS1 rs2943634 with low postprogram carbohydrate intake, and MC4R rs17782313 with low postprogram total fat and saturated fatty acid intakes (P < .05). Although significant associations did not survive correction for multiple comparisons using the Benjamini-Hochberg method in this exploratory study, polymorphisms in IRS1, IRS2, MC3R, and MC4R influence metabolic and inflammatory status in Brazilian adults. IRS1 and MC4R variants may influence carbohydrate, total fat, and saturated fatty acid intakes in response to a diet-oriented program in subjects with obesity. Show less

Alzheimer's disease causes chronic neurodegeneration and is the leading cause of dementia in the world. The causes of this disease are not fully understood but seem to involve two essential cerebral pathways: cholinergic and amyloid. The simultaneous inhibition of AChE, BuChE, and BACE-1, essential enzymes involved in those pathways, is a promising therapeutic approach to treat the symptoms and, hopefully, also halt the disease progression. This study sought to identify triple enzymatic inhibitors based on stereo-electronic requirements deduced from molecular modeling of AChE, BuChE, and BACE-1 active sites. A pharmacophore model was built, displaying four hydrophobic centers, three hydrogen bond acceptors, and one positively charged nitrogen, and used to prioritize molecules found in virtual libraries. Compounds showing adequate overlapping rates with the pharmacophore were subjected to molecular docking against the three enzymes and those with an adequate docking score ( Show less

There are few causes of treatable neurodevelopmental diseases described to date. Branched-chain ketoacid dehydrogenase kinase (BCKDK) deficiency causes branched-chain amino acid (BCAA) depletion and is linked to a neurodevelopmental disorder characterized by autism, intellectual disability and microcephaly. We report the largest cohort of patients studied, broadening the phenotypic and genotypic spectrum. Moreover, this is the first study to present newborn screening findings and mid-term clinical outcome. In this cross-sectional study, patients with a diagnosis of BCKDK deficiency were recruited via investigators' practices through a MetabERN initiative. Clinical, biochemical and genetic data were collected. Dried blood spot (DBS) newborn screening (NBS) amino acid profiles were retrieved from collaborating centres and compared to a healthy newborn reference population. Twenty-one patients with BCKDK mutations were included from 13 families. Patients were diagnosed between 8 months and 16 years (mean: 5.8 years, 43% female). At diagnosis, BCAA levels (leucine, valine and isoleucine) were below reference values in plasma and in CSF. All patients had global neurodevelopmental delay; 18/21 had gross motor function (GMF) impairment with GMF III or worse in 5/18, 16/16 intellectual disability, 17/17 language impairment, 12/17 autism spectrum disorder, 9/21 epilepsy, 12/15 clumsiness, 3/21 had sensorineural hearing loss and 4/20 feeding difficulties. No microcephaly was observed at birth, but 17/20 developed microcephaly during follow-up. Regression was reported in six patients. Movement disorder was observed in 3/21 patients: hyperkinetic movements (1), truncal ataxia (1) and dystonia (2). After treatment with a high-protein diet (≥ 2 g/kg/day) and BCAA supplementation (100-250 mg/kg/day), plasma BCAA increased significantly (P < 0.001), motor functions and head circumference stabilized/improved in 13/13 and in 11/15 patients, respectively. Among cases with follow-up data, none of the three patients starting treatment before 2 years of age developed autism at follow-up. The patient with the earliest age of treatment initiation (8 months) showed normal development at 3 years of age. NBS in DBS identified BCAA levels significantly lower than those of the normal population. This work highlights the potential benefits of dietetic treatment, in particular early introduction of BCAA. Therefore, it is of utmost importance to increase awareness about this treatable disease and consider it as a candidate for early detection by NBS programmes. Show less

CETP activity reduces plasma HDL-cholesterol concentrations, a correlate of an increased risk of atherosclerotic events. However, our recent findings suggest that CETP expression in macrophages promotes an intracellular antioxidant state, reduces free cholesterol accumulation and phagocytosis, and attenuates pro-inflammatory gene expression. To determine whether CETP expression in macrophages affects atherosclerosis development, we transplanted bone marrow from transgenic mice expressing simian CETP or non-expressing littermates into hypercholesterolemic LDL-receptor-deficient mice. The CETP expression did not change the lipid-stained lesion areas but decreased the macrophage content (CD68), neutrophil accumulation (LY6G), and TNF-α aorta content of young male transplanted mice and decreased LY6G, TNF-α, iNOS, and nitrotyrosine (3-NT) in aged female transplanted mice. These findings suggest that CETP expression in bone-marrow-derived cells reduces the inflammatory features of atherosclerosis. These novel mechanistic observations may help to explain the failure of CETP inhibitors in reducing atherosclerotic events in humans. Show less

Ovulatory disorders are a major cause of infertility in humans as well as economically important species. In physiological conditions, the LH surge induces the expression of epidermal growth factor (EGF)-like ligands that activate the EGR receptor (EGFR) and subsequently the mitogen-activated protein kinase (MAPK) pathway. The magnitude and duration of MAPK phosphorylation are regulated by dual-specificity phosphatases (DUSPs). Besides this well-known cascade, other signaling pathways such as the Hippo pathway modulate the ovulatory cascade and are reported to crosstalk with MAPK signaling. Here, we tested the hypothesis that LH and the Hippo pathway regulate DUSP expression in bovine pre-ovulatory granulosa cells. The abundance of DUSP6 mRNA but not DUSP1 was decreased by LH (P < 0.05). Cells were then pre-treated (1 h) with two inhibitors of Hippo signaling, verteporfin (1 µM) or peptide-17 (25 µM), before exposure for 6 h to LH or to EGF. Treatment with verteporfin increased DUSP1 mRNA levels (P < 0.05) in the presence or absence of EGF or LH and treatment with peptide-17 increased DUSP6 and not DUSP1 mRNA abundance. These data indicate a differential regulation of DUSP1 and DUSP6 mRNA by the Hippo pathway in pre-ovulatory granulosa cells, which suggests a complex control of MAPK signaling around ovulation. Show less

The purpose of this study was to examine whether myeloid dendritic cells (mDCs) from patients with multiple sclerosis (MS) and healthy controls (HCs) become similarly tolerogenic when exposed to IL-27 as this may represent a potential mechanism of autoimmune dysregulation. Our study focused on natural mDCs that were isolated from HCs and MS patient peripheral blood mononuclear cells (PBMCs). After a 24-h treatment with IL-27 ± lipopolysaccharide (LPS), the mDCs were either harvested to identify IL-27-regulated gene expression or co-cultured with naive T-cells to measure how the treated DC affected T-cell proliferation and cytokine secretion. mDCs isolated from HCs but not untreated MS patients became functionally tolerogenic after IL-27 treatment. Although IL-27 induced both HC and untreated MS mDCs to produce similar amounts of IL-10, the tolerogenic HC mDCs expressed PD-L2, IDO1, and SOCS1, while the non-tolerogenic untreated MS mDCs expressed IDO1 and IL-6R. Cytokine and RNA analyses identified two signature blocks: the first identified genes associated with mDC tolerizing responses to IL-27, while the second was associated with the presence of MS. In contrast to mDCs from untreated MS patients, mDCs from HCs and IFNb-treated MS patients became tolerogenic in response to IL-27. The genes differentially expressed in the different donor IL-27-treated mDCs may contain targets that regulate mDC tolerogenic responses. Show less

Nuclear Pore Complexes (NPCs) are embedded in the nuclear envelope (NE), regulating macromolecule transport and physically interacting with chromatin. The NE undergoes dramatic breakdown and reformation during plant cell division. In addition, this structure has a specific meiotic function, anchoring and positioning telomeres to facilitate the pairing of homologous chromosomes. To elucidate a possible function of the structural components of the NPCs in meiosis, we have characterized several Arabidopsis lines with mutations in genes encoding nucleoporins belonging to the outer ring complex. Plants defective for either SUPPRESSOR OF AUXIN RESISTANCE1 (SAR1, also called NUP160) or SAR3 (NUP96) present condensation abnormalities and SPO11-dependent chromosome fragmentation in a fraction of meiocytes, which is increased in the double mutant Show less

A diet deficient in donors of methyl group, such as methionine, affects DNA methylation and hepatic lipid metabolism. Methionine also affects other epigenetic mechanisms, such as microRNAs. We investigated the effects of methionine-supplemented or methionine-deficient diets on the expression of chromatin-modifying genes, global DNA methylation, the expression and methylation of genes related to lipid metabolism, and the expression of microRNAs in mouse liver. Female Swiss albino mice were fed a control diet (0.3% methionine), a methionine-supplemented diet (2% methionine), and a methionine-deficient diet (0% methionine) for 10 weeks. The genes most affected by the methionine-supplemented diet were associated with histone and DNA methyltransferases activity, while the methionine-deficient diet mostly altered the expression of histone methyltransferases genes. Both diets altered the global DNA methylation and the expression and gene-specific methylation of the lipid metabolism gene Apoa5. Both diets altered the expression of several liver homeostasis-related microRNAs, including miR-190b-5p, miR-130b-3p, miR-376c-3p, miR-411-5p, miR-29c-3p, miR-295-3p, and miR-467d-5p, with the methionine-deficient diet causing a more substantial effect. The effects of improper amounts of methionine in the diet on liver pathologies may involve a cooperative action of chromatin-modifying genes, which results in an aberrant pattern of global and gene-specific methylation, and microRNAs responsible for liver homeostasis. Show less

Mass spectrometry (MS)-based techniques can be a powerful tool to identify neuropsychiatric disorder biomarkers, improving prediction and diagnosis ability. Here, we evaluate the efficacy of MS proteomics applied to human peripheral fluids of schizophrenia (SCZ) patients to identify disease biomarkers and relevant networks of biological pathways. Following PRISMA guidelines, a search was performed for studies that used MS proteomics approaches to identify proteomic differences between SCZ patients and healthy control groups (PROSPERO database: CRD42021274183). Nineteen articles fulfilled the inclusion criteria, allowing the identification of 217 differentially expressed proteins. Gene ontology analysis identified lipid metabolism, complement and coagulation cascades, and immune response as the main enriched biological pathways. Meta-analysis results suggest the upregulation of FCN3 and downregulation of APO1, APOA2, APOC1, and APOC3 in SCZ patients. Despite the proven ability of MS proteomics to characterize SCZ, several confounding factors contribute to the heterogeneity of the findings. In the future, we encourage the scientific community to perform studies with more extensive sampling and validation cohorts, integrating omics with bioinformatics tools to provide additional comprehension of differentially expressed proteins. The produced information could harbor potential proteomic biomarkers of SCZ, contributing to individualized prognosis and stratification strategies, besides aiding in the differential diagnosis. Show less

The polymorphisms of fatty acid desaturase genes FADS1 and FADS2 have been associated with an increase in weight gain. We investigated FADS1 and FADS2 gene polymorphisms and the relation between ω-3 and ω-6 fatty acid plasma concentrations and gestational weight gain. A prospective cohort study of 199 pregnant women was followed in Santo Antônio de Jesus, Brazil. Plasma levels of polyunsaturated fatty acids (PUFAs) were measured at baseline and gestational weight gain during the first, second, and third trimesters. Fatty acid recognition was carried out with the aid of gas chromatography. Single nucleotide polymorphisms (SNPs) were genotyped using real-time PCR. Statistical analyses included Structural Equation Modelling. A direct effect of FADS1 and FADS2 gene polymorphisms on gestational weight was observed; however, only the SNP rs174575 (FADS2) showed a significant positive direct effect on weight over the course of the pregnancy (0.106; Show less

Sickle cell disease (SCD) is a well-studied monogenetic disease with an established chronic inflammatory component. The paradigm shift towards inflammation has made the pathophysiology of SCD even more complex. Studies have shown that an imbalance between the pro-inflammatory and anti-inflammatory cytokines in SCD exists; however, the reports are skewed toward the pro-inflammatory mediators. We enumerate recent in vitro and in vivo studies on anti-inflammatory cytokines in SCD patients, and discuss the biology of anti-inflammatory cytokines including the already reported IL-2, TGF-β, and IL-10 as well as the recently discovered IL-27, IL-35 and IL-37. This review will improve the understanding of the pathophysiology of SCD and aid in the search of new therapeutic options for patients with SCD. Show less

Sudden cardiac death (SCD) in young people is predominantly caused by genetic causes as cardiomyopathies. Hypertrophic cardiomyopathy is the most common genetic cardiovascular disease and is responsible for the major proportion of SCD in the young. The purpose of this study was to identify the genetic variants present in young SCD victims with HCM characteristics. From the Portuguese records of autopsies performed at the National Institute of Legal Medicine and Forensic Sciences, North Delegation, 16 young (16-50 years) SCD victims whose death was suspected to be a manifestation of HCM were selected. Using next-generation sequencing, the coding regions of 40 genes associated with HCM, candidates, or strongly related to HCM-phenocopies were investigated. The victims included in this study were all males, with a mean age of 33.4 ± 11.7 years, left ventricle mean thickness of 21.5 ± 6.28 mm, and the majority of deaths occurred during sleep (36%). A pathogenic or likely pathogenic variant was identified in six out of 16 (37.5%) victims, in the most common HCM genes (MYBPC3 and MYH7). Our results indicate that molecular autopsy of SCD victims contributes to a more precise identification of a cause of death, and this can be used in the prevention of SCD cases through family screening of first relatives who may carry the same pathogenic variant. Show less

The melanocortin-4 receptor (MC4R) plays an important role in appetite. Agonist ligands that stimulate the MC4R decrease appetite, while antagonist compounds increase food consumption. Herein, a functional mixture-based positional scan identified novel MC4R antagonist sequences. Mixtures comprising a library of 12,960,000 tetrapeptides were screened in the presence and absence of the NDP-MSH agonist. These results led to the synthesis of 48 individual tetrapeptides, of which 40 were screened for functional activity at the melanocortin receptors. Thirteen compounds were found to possess nanomolar antagonist potency at the MC4R, with the general tetrapeptide sequence Ac-Aromatic-Basic-Aromatic-Basic-NH Show less

The central melanocortin-3 and melanocortin-4 receptors (MC3R, MC4R) are key regulators of body weight and energy homeostasis. Herein, the discovery and characterization of first-in-class small molecule melanocortin agonists with selectivity for the melanocortin-3 receptor over the melanocortin-4 receptor are reported. Identified via "unbiased" mixture-based high-throughput screening approaches, pharmacological evaluation of these pyrrolidine bis-cyclic guanidines resulted in nanomolar agonist activity at the melanocortin-3 receptor. The pharmacological profiles at the remaining melanocortin receptor subtypes tested indicated similar agonist potencies at both the melanocortin-1 and melanocortin-5 receptors and antagonist or micromolar agonist activities at the melanocortin-4 receptor. This group of small molecules represents a new area of chemical space for the melanocortin receptors with mixed receptor pharmacology profiles that may serve as novel lead compounds to modulate states of dysregulated energy balance. Show less

To discuss advances on the RNA-targeted therapies to treat dyslipidemia with the aim of reducing atherosclerotic cardiovascular disease (ASCVD). Genetic studies have paved the way for therapies that reduce translation of proteins that play causal roles in dyslipidemia and atherosclerosis like proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein B-100 (apoB), apolipoprotein(a) [apo(a)], apolipoprotein C3 (apoC3), and angiopoietin-like 3 (ANGPTL3). Either antisense oligonucleotide (ASO) therapies and small interfering RNA (siRNA) molecules inhibit protein synthesis and consequently improve dyslipidemia. Most of these molecules contain N-acetylgalactosamine (GalNAc) moieties that have high specificity for hepatocytes and therefore reduce concentration in other tissues. Inclisiran, an siRNA for PCSK9, has shown robust LDL-C reductions, with good tolerability, in severe forms of hypercholesterolemia as well as in high cardiovascular disease patients with injections every 3 to 6 months. Pelacarsen is an ASO against apolipoprotein(a) that reduces Lp(a) up to 80% with good tolerability. Either inclisiran or pelacarsen is being tested to show it can prevent ASCVD. AMG 890, an siRNA compound aimed at reducing apo(a) synthesis, is also under investigation. Volanesorsen is an ASO against apoC3 that reduces triglyceride levels up to 70% and is being tested in severe hypertriglyceridemic patients. Vupanorsen is an ASO against ANGPTL3 that reduced triglyceride levels 36-53% among moderate hypertriglyceridemic individuals. Interestingly, it also reduces ApoC3 and non-HDL cholesterol and apoB; however, it lowers HDL cholesterol. RNA-targeted therapies are being extensively tested for dyslipidemia treatment with promising results. Show less

Psychosis is a highly heritable and heterogeneous psychiatric condition. Its genetic architecture is thought to be the result of the joint effect of common and rare variants. Families with high prevalence are an interesting approach to shed light on the rare variant's contribution without the need of collecting large cohorts. To unravel the genomic architecture of a family enriched for psychosis, with four affected individuals, we applied a system genomic approach based on karyotyping, genotyping by whole-exome sequencing to search for rare single nucleotide variants (SNVs) and SNP array to search for copy-number variants (CNVs). We identified a rare non-synonymous variant, g.39914279 C > G, in the Show less

We report the death of a 22-year-old woman, with a 3½ year history of cyclic vomiting and cannabis use since age 14, who developed torsades de pointes cardiac arrythmia while being treated in the emergency room for nausea and vomiting. Resuscitation restored spontaneous cardiac circulation, however, due to post-cardiac arrest anoxic brain injury, she never regained consciousness and was declared brain dead 4 days later. Postmortem examination confirmed hypoxic-ischemic encephalopathy, in keeping with the in-hospital diagnosis of brain death. The heart was anatomically normal but showed signs of acute post-cardiopulmonary arrest reperfusion injury. As a consequence of limited survival in hospital in a neuro-vegetative state, early bronchopneumonia and isolated pulmonary thromboemboli were seen. Toxicological studies confirmed cannabis use, in addition to the presence of haloperidol and ondansetron. Genetic studies were performed to rule out a possible channelopathy and revealed a mutation in the MYBPC3 and RYR2 genes. Death in this woman with cannabinoid hyperemesis syndrome was attributed to a fatal cardiac arrhythmia complicating vomiting-induced hypokalemia and treatment with QT interval prolonging and potentially arrhythmogenic medications, with the identified cardiac genetic mutations listed as contributing factors. The emphasis of this report is a) to raise awareness that death can occur due to cyclic vomiting, b) provide a brief but practical overview of cannabinoid hyperemesis syndrome, c) describe the findings from our postmortem examination and come to the most reasonable cause and mechanism of death, d) comment on the risk factors associated with torsades de pointes cardiac arrythmia, and e) conclude that a complete postmortem examination is needed to exclude an anatomical or toxicological cause of death in cannabinoid hyperemesis syndrome, a disabling but preventable disorder. Show less

Hypertrophic cardiomyopathy (HCM) is the most common form of hereditary cardiomyopathy. It is characterized by an unexplained non-dilated hypertrophy of the left ventricle with a conserved or elevated ejection fraction. It is a genetically heterogeneous disease largely caused by variants of genes encoding for cardiac sarcomere proteins, including Show less

Cancer stem cells (CSC) are considered responsible for tumor initiation, therapeutic resistance, and metastasis. A comprehensive knowledge of the mechanisms governing the acquisition and maintenance of cancer stemness is crucial for the development of new therapeutic approaches in oncology. E2A basic helix-loop-helix (bHLH) transcription factors are associated with epithelial-mesenchymal transition (EMT) and tumor progression, but knowledge of their functional contributions to cancer biology is still limited. Using a combination of Show less

The HDL (high-density lipoprotein)-mediated stimulation of cellular cholesterol efflux initiates macrophage-specific reverse cholesterol transport (m-RCT), which ends in the fecal excretion of macrophage-derived unesterified cholesterol (UC). Early studies established that LDL (low-density lipoprotein) particles could act as efficient intermediate acceptors of cellular-derived UC, thereby preventing the saturation of HDL particles and facilitating their cholesterol efflux capacity. However, the capacity of LDL to act as a plasma cholesterol reservoir and its potential impact in supporting the m-RCT pathway in vivo both remain unknown. We investigated LDL contributions to the m-RCT pathway in hypercholesterolemic mice. Macrophage cholesterol efflux induced in vitro by LDL added to the culture media either alone or together with HDL or ex vivo by plasma derived from subjects with familial hypercholesterolemia was assessed. In vivo, m-RCT was evaluated in mouse models of hypercholesterolemia that were naturally deficient in CETP (cholesteryl ester transfer protein) and fed a Western-type diet. LDL induced the efflux of radiolabeled UC from cultured macrophages, and, in the simultaneous presence of HDL, a rapid transfer of the radiolabeled UC from HDL to LDL occurred. However, LDL did not exert a synergistic effect on HDL cholesterol efflux capacity in the familial hypercholesterolemia plasma. The m-RCT rates of the LDLr (LDL receptor)-KO (knockout), LDLr-KO/APOB100, and PCSK9 (proprotein convertase subtilisin/kexin type 9)-overexpressing mice were all significantly reduced relative to the wild-type mice. In contrast, m-RCT remained unchanged in HAPOB100 Tg (human APOB100 transgenic) mice with fully functional LDLr, despite increased levels of plasma APO (apolipoprotein)-B-containing lipoproteins. Hepatic LDLr plays a critical role in the flow of macrophage-derived UC to feces, while the plasma increase of APOB-containing lipoproteins is unable to stimulate m-RCT. The results indicate that, besides the major HDL-dependent m-RCT pathway via SR-BI (scavenger receptor class B type 1) to the liver, a CETP-independent m-RCT path exists, in which LDL mediates the transfer of cholesterol from macrophages to feces. Graphical Abstract: A graphical abstract is available for this article. Show less

Low concentrations of high-density lipoprotein cholesterol (HDL-C) represent a well-established cardiovascular risk factor. Paradoxically, extremely high HDL-C levels are equally associated with elevated cardiovascular risk, resulting in the U-shape relationship of HDL-C with cardiovascular disease. Mechanisms underlying this association are presently unknown. We hypothesised that the capacity of high-density lipoprotein (HDL) to acquire free cholesterol upon triglyceride-rich lipoprotein (TGRL) lipolysis by lipoprotein lipase underlies the non-linear relationship between HDL-C and cardiovascular risk. To assess our hypothesis, we developed a novel assay to evaluate the capacity of HDL to acquire free cholesterol (as fluorescent TopFluor® cholesterol) from TGRL upon in vitro lipolysis by lipoprotein lipase. When the assay was applied to several populations markedly differing in plasma HDL-C levels, transfer of free cholesterol was significantly decreased in low HDL-C patients with acute myocardial infarction (-45%) and type 2 diabetes (-25%), and in subjects with extremely high HDL-C of >2.59 mmol/L (>100 mg/dL) (-20%) versus healthy normolipidaemic controls. When these data were combined and plotted against HDL-C concentrations, an inverse U-shape relationship was observed. Consistent with these findings, animal studies revealed that the capacity of HDL to acquire cholesterol upon lipolysis was reduced in low HDL-C apolipoprotein A-I knock-out mice and was negatively correlated with aortic accumulation of [ Free cholesterol transfer to HDL upon TGRL lipolysis may underlie the U-shape relationship between HDL-C and cardiovascular disease, linking HDL-C to triglyceride metabolism and atherosclerosis. Show less

Glucagon is well known to regulate blood glucose but may be equally important for amino acid metabolism. Plasma levels of amino acids are regulated by glucagon-dependent mechanism(s), while amino acids stimulate glucagon secretion from alpha cells, completing the recently described liver-alpha cell axis. The mechanisms underlying the cycle and the possible impact of hepatic steatosis are unclear. We assessed amino acid clearance in vivo in mice treated with a glucagon receptor antagonist (GRA), transgenic mice with 95% reduction in alpha cells, and mice with hepatic steatosis. In addition, we evaluated urea formation in primary hepatocytes from ob/ob mice and humans, and we studied acute metabolic effects of glucagon in perfused rat livers. We also performed RNA sequencing on livers from glucagon receptor knock-out mice and mice with hepatic steatosis. Finally, we measured individual plasma amino acids and glucagon in healthy controls and in two independent cohorts of patients with biopsy-verified non-alcoholic fatty liver disease (NAFLD). Amino acid clearance was reduced in mice treated with GRA and mice lacking endogenous glucagon (loss of alpha cells) concomitantly with reduced production of urea. Glucagon administration markedly changed the secretion of rat liver metabolites and within minutes increased urea formation in mice, in perfused rat liver, and in primary human hepatocytes. Transcriptomic analyses revealed that three genes responsible for amino acid catabolism (Cps1, Slc7a2, and Slc38a2) were downregulated both in mice with hepatic steatosis and in mice with deletion of the glucagon receptor. Cultured ob/ob hepatocytes produced less urea upon stimulation with mixed amino acids, and amino acid clearance was lower in mice with hepatic steatosis. Glucagon-induced ureagenesis was impaired in perfused rat livers with hepatic steatosis. Patients with NAFLD had hyperglucagonemia and increased levels of glucagonotropic amino acids, including alanine in particular. Both glucagon and alanine levels were reduced after diet-induced reduction in Homeostatic Model Assessment for Insulin Resistance (HOMA-IR, a marker of hepatic steatosis). Glucagon regulates amino acid metabolism both non-transcriptionally and transcriptionally. Hepatic steatosis may impair glucagon-dependent enhancement of amino acid catabolism. Show less