Biology subjects

Alves, S.

Publications and source records attributed to Alves, S..

12 recordsLinked to original sources

bioRxiv2026

Hypothalamic CYP46A1 cholesterol metabolism regulates diet-induced obesity

Obesity is a growing global health challenge which affects over 38% of the population and increases the risk of developing metabolic disorders. Effective long-term treatment options remain limited and often lead to significant side effects. The hypothalamus plays a central role in metabolic regulation by integrating peripheral and central signals to maintain energy homeostasis. While the hypothalamus regulates peripheral lipid metabolism, the role of lipid metabolic pathways within the hypothalamus itself remains unclear. Therefore, the molecular mechanisms linking hypothalamic activity to the development of obesity remain poorly understood. Given that cholesterol is the most abundant brain lipid, we investigated molecular players involved in its local regulation. Here, we identify the rate-limiting enzyme for brain cholesterol degradation, Cyp46a1, as a critical regulator of diet-induced obesity. We show that Cyp46a1 expression is significantly reduced in the hypothalamus of C57BL/6J mice exposed to a high-fat diet, suggesting a role in metabolic dysregulation. We used recombinant Adeno-Associated Viruses (AAV) to modulate Cyp46a1 expression in the arcuate nucleus, a key hypothalamic region regulating energy balance. We evaluated longitudinal changes in body weight, adipocyte size, PPAR-{gamma} expression, and hepatic lipid accumulation and pancreatic histopathology in mice undergoing chow or high fat diets. These experiments demonstrated that hypothalamic Cyp46a1 regulates body weight, adipocyte size, and hepatic and pancreatic histopathology. Conversely, CYP46A1 overexpression protects against high-fat diet-induced obesity and improves glucose homeostasis and insulin sensitivity, likely via crosstalk with hepatic and pancreatic function. Moreover, we found that hypothalamic CYP46A1 expression selectively modulates gut microbiota composition, linking this enzyme to the microbiota-gut-brain axis. Finally, we found that Cyp46a1 levels influence cognitive and motor performance, suggesting broader physiological relevance. Collectively, our findings reveal a previously unrecognized role of hypothalamic Cyp46a1 and cholesterol pathway control in obesity pathophysiology and metabolic homeostasis. These findings identify hypothalamic Cyp46a1 as a promising therapeutic target for obesity and its related comorbidities.

neuroscience↗

bioRxiv2025

WFS1E864K in humans and mice causes Wolfram-like syndrome optic atrophy via early axonal mitochondrial dysfunction

Wolfram-like syndrome leads to retinal ganglion cell degeneration and vision loss. Wolfram-like syndrome is primarily caused by variants in the WFS1 gene, which encodes an endoplasmic reticulum resident transmembrane protein, Wolframin. To date, the disease mechanism remains unclear, and no therapies are available. Here, we generated a mouse model carrying the pathogenic WFS1E864K allele that recapitulated key features of human Wolfram-like syndrome, including bilateral optic atrophy, retinal nerve fiber thinning and lamination of the outer plexiform layer. We demonstrated, using the Wfs1E864K mouse model, that alteration of the protein leads to impairments of retinal ganglion cell function, associated with a thinning of the inner retina layer and nerve fibers. These alterations are associated with myelin disorganization, axonal death, mitochondrial alterations in the axons, and impairment of endoplasmic reticulum-mitochondria communication in the soma. Our data showed that primary deficits are localized in the optic nerve before progressing towards the retinal ganglion cell soma. RNAseq analysis identified several altered signaling pathways such as in lipid metabolism, glia activation response, metabolic stress, organelle transport and quality control. These findings highlighted the critical role of Wolframin in optic nerve mitochondrial physiology, providing us with a pertinent model to develop novel innovative therapeutic strategies.

neuroscience↗

bioRxiv2025

Structural variants are enriched in deleterious visible phenotypes in Drosophila

Genome structural variants (SVs) comprise a sizable portion of functionally important genetic variation in all organisms; yet, many SVs evade discovery using short reads. While long-read sequencing can find the hidden SVs, the role of SVs in variation in organismal traits remains largely unclear. To address this gap, we investigate the molecular basis of 50 classical phenotypes in 11 Drosophila melanogaster strains using highly contiguous de novo genome assemblies generated with Oxford Nanopore long reads. These assemblies enabled the creation of a pangenome graph containing comprehensive, nucleotide-resolution maps of SVs, including complex rearrangements such as the interchromosomal inverted duplication Dp(2;4)eyD and large tandem duplications at the Bar locus. We uncovered new candidate causal mutations for 15 phenotypes and new molecular alleles for 2 mutations comprising tandem duplications, transposable element (TE) insertions, and indels. For example, we mapped the tarsal joint defect AblpeyD to an 8 kb Roo retrotransposon insertion into an intergenic enhancer, a finding validated via CRISPR-Cas9. The wing vein phenotype plexus (px1) was linked to a 1.5 kb partial tandem gene duplication, and the century-old Curved (c1) wing phenotype was linked to a 7.5 kb DM412 retrotransposon inserted into the coding sequence of the muscle protein gene Strn-Mlck. We also unveiled 8 SV alleles of previously identified causal genes, including previously uncharacterized SVs underlying the extensively studied white and yellow phenotypes. Overall, 67.4% of the genes causing phenotypic changes harbored candidate SVs over 100 bp, whereas only 28% is expected based on euchromatic SVs. Our data, based on the 50 Drosophila phenotypes, 44 of which are strongly deleterious, suggests a disproportionately larger contribution of SVs to deleterious changes in visible phenotypes in Drosophila.

genomics↗

bioRxiv2025

LHR and Gαs trafficking drive sustained cAMP signalling from endosomes to control steroidogenesis

1.A growing number of G protein-coupled receptors (GPCRs) signal through G proteins from intracellular compartments following endocytosis. While for few receptors the physiological relevance of such mechanism has been established, the relationships between the spatio-temporal organization of cellular signalling and the physiological responses are still to be elucidated for most receptors. Signalling by the luteinizing hormone receptor (LHR) is essential to regulate sex steroids production in gonads, but how G protein-dependent signals from endosomes are functionally important for steroidogenesis remains unexplored. Here, we demonstrate that transient LHR activation promotes a prolonged Gs/cAMP signalling from endosomes, which requires ligand-induced independent receptor and Gs trafficking. We show that endosomal trafficking is specifically required for ligand-induced cAMP accumulation in the nucleus and gene expression, as well as for steroids production in Leydig cells. Thus, this study contributes to further understand the molecular mechanisms by which LHR, through signalling compartmentalization, controls gonadal steroidogenesis.

cell biology↗

bioRxiv2023

The Wolfram-like variant WFS1E864K destabilizes MAM and compromises autophagy and mitophagy in human and mice.

Dominant variants in WFS1, a gene coding for the mitochondria-associated endoplasmic reticulum (ER) membrane (MAM) resident protein Wolframin, have been associated with Wolfram-like syndrome (WLS). In vitro and in vivo, WFS1 loss results in reduced ER to mitochondria calcium (Ca2+) transfer, mitochondrial dysfunction, and enhanced autophagy and mitophagy. However, in WLS pathological context, whether the mutant protein triggers the same cellular processes is unknown. Here, we show that, in human fibroblasts and murine neuronal cultures, WLS protein WFS1E864K leads to decreases in mitochondria bioenergetics and Ca2+ uptake, deregulation of the mitochondrial quality system mechanisms, and alteration of the autophagic flux. Moreover, in the Wfs1E864K mouse, these alterations are concomitant with a decrease of MAM number. These findings reveal pathophysiological similarities between WS and WLS, highlighting the importance of WFS1 for MAMs integrity and functionality. It may open new treatment perspectives, until now non-existent, for patients with WLS.

neuroscience↗

bioRxiv2023

Analysis of DNA transposition by DNA transposases in human cells

This manuscript discusses the recent report "Cognate restriction of transposition by piggyBac-like proteins" in Nucleic Acids Research by Beckermann et al and related recent publications about the inability to detect DNA transposition activity of human domesticated DNA transposase PGBD5. Measuring DNA transposition activity of transposases in human cells, where these enzymes can act on endogenous genomic substrates and induce DNA damage, is complicated by these and other cellular responses. Possible reasons for the discordant findings of Beckermann et al with prior independent reports of PGBD5 DNA transposition by Helou et al and Henssen et al and specific details of experimental methods in human cells are presented. In particular, by using independent experiments that reproduce PGBD5-mediated genomic integration, we demonstrate how supraphysiologic and ectopic overexpression of PGBD5 can cause DNA damage and cell death, and artifactual loss of apparent activity in clonogenic transposition reporter assays. While PGBD5 can support apparent DNA transposition, its cellular activity predominantly involves double-strand DNA breaks, deletions and other DNA rearrangements. We discuss the implications of this phenomenon for the interpretation of experimental assays and activities of domesticated DNA transposases.

molecular biology↗

bioRxiv2023

FLT3 signaling inhibition preserves opioid analgesia while abrogating tolerance and hyperalgesia

Opioid analgesia is counteracted on chronic use by tolerance and hyperalgesia inducing dose escalation and life-threatening overdoses. Mu opiate receptors (MOR) expressed in primary sensory neurons were recently found to control tolerance and hyperalgesia, but the underlying mechanisms remained elusive. Here we show that genetic inactivation of fms-like tyrosine kinase receptor 3 (FLT3) receptor in sensory neurons abrogates morphine tolerance and hyperalgesia by preventing MOR-induced hyperactivation of the cAMP signaling pathway and subsequent excitatory adaptive processes. Moreover, the specific FLT3 inhibitor BDT001 potentiates morphine analgesia in acute and chronic pain models, without aggravating morphine adverse effects, and reverses tolerance and hyperalgesia once installed. Thus, FLT3 appears as a key regulator of the MOR signaling pathway and its pharmacological blockade shows promise to enhance chronic opioid analgesic efficacy.

neuroscience↗

bioRxiv2022

Development of a high-throughput barrier function assay using primary human gut organoids

Disruptions in the gut epithelial barrier can lead to the development of chronic indications such as inflammatory bowel disease (IBD). Historically, barrier function has been assessed in cancer cell lines, which do not contain all human intestinal cell types, leading to poor translatability. To bridge this gap, we adapted human primary gut organoids grown as monolayers to assess barrier function. In this work we describe and characterize a novel 96-well human gut organoid-derived monolayer system that enables medium/high-throughput quantitative assessment of candidate therapeutics. Normal human intestine differentiation patterns and barrier function were characterized and confirmed to recapitulate key aspects of in vivo biology. Next, cellular response to TNF- (a central driver of IBD) was determined using a diverse cadre of readouts.These outputs included transcription factor phosphorylation, target gene expression, cytokine/chemokine production, and barrier function. Additionally, we showed that TNF- pathway antagonists rescued damage caused by TNF- in a dose-dependent manner, indicating that this system is suitable for quantitative assessment of barrier modulating factors. Taken together, we have established a robust primary cell-based 96-well system capable of interrogating questions around mucosal response. This system is well suited to provide pivotal functional data to support translational target and drug discovery efforts.

immunology↗

bioRxiv2022

Genetic analysis of global faba bean germplasm maps agronomic traits and identifies strong selection signatures for geographical origin

Faba bean (Vicia faba L.) is a high-protein grain legume crop with great potential for further cultivation. However, little is known about the genetics underlying trait diversity. In this study, we use 21,345 high-quality SNP markers to genetically characterise 2,678 faba bean genotypes. We perform genome-wide association studies of key agronomic traits using a Seven-parent-MAGIC population and detect 238 significant marker-trait associations linked to 12 traits of agronomic importance, with 65 of these being stable across multiple environments. Using a non-redundant diversity panel of 685 accessions from 52 countries, we identify 3 subpopulations differentiated by geographical origin and 33 genomic regions subject to strong diversifying selection between subpopulations. We find that SNP markers associated with the differentiation of northern and southern accessions were able to explain a significant proportion of agronomic trait variance in the Seven-parent-MAGIC population, suggesting that some of these traits have played an important role in breeding. Altogether, our findings point to genomic regions associated with important agronomic traits and selection in faba bean, which can be used for breeding purposes. Key MessageWe identified marker-trait associations for key faba bean agronomic traits and genomic signatures of selection within a global germplasm collection.

genetics↗

bioRxiv2020

The smORF-containing gene mille-pattes is required for moulting and Trypanosoma cruzi metacyclogenesis in the Chagas disease vector Rhodnius prolixus

Chagas disease is estimated to affect 8 million people worldwide and is responsible for circa 10,000 deaths in Latin America every year. Vector control has been developed as the main strategy to control disease spreading. The identification of new targets is essential, and genes containing small open reading frames (smORFs - < 100 amino acids) are present as hundreds of putative new candidate targets in insect genomes. Here, we show that the prototypic smORF containing gene mille-pattes/polished-rice/tarsalless (mlpt/pri/tal) is essential for post-embryonic development of the kissing bug Rhodnius prolixus and for the metacyclogenesis of the Trypanosoma cruzi parasite during nymphal stages. Injection of double-stranded RNA against mlpt (Rp-dsmlpt) during nymphal stages leads to a plethora of phenotypes which impairs post-embryonic development. First, nymphs of fourth or fifth stage injected with Rp-dsmlpt do not moult. Second, vector digestive physiology is largely modified, and haemozoin is significantly increased in the posterior midgut of Rp-dsmlpt nymphs. Third, Rp-mlpt knockdown inhibits the metacyclogenesis of Trypanosoma cruzi, the etiologic agent of Chagas disease. Thus, our study provides the first evidence of a smORF-containing gene regulating vector physiology, parasitic cycle and disease transmission.

molecular biology↗

bioRxiv2020

A Micro-Engineered Airway Lung-Chip Models Key Features of Viral-Induced Exacerbation of Asthma

RationaleViral-induced exacerbation of asthma remain a major cause of hospitalization and mortality. New human relevant models of the airways are urgently needed to understand how respiratory infections may trigger asthma attacks, and to advance treatment development. ObjectivesTo develop a new human relevant model of rhinovirus-induced asthma exacerbation that recapitulates viral infection of asthmatic airway epithelium, neutrophil transepithelial migration, and enables evaluation of immunomodulatory therapy. MethodsA micro-engineered model of fully differentiated human mucociliary airway epithelium was stimulated with IL-13 to induce a Th2-type asthmatic phenotype and infected with live human rhinovirus 16 (HRV16) to reproduce key features of viral-induced asthma exacerbation. Measurements and Main ResultsInfection with HRV16 replicated key hallmarks of the cytopathology and inflammatory responses observed in human airways. Generation of a Th2 microenvironment through exogenous IL-13 stimulation induced features of asthmatics airways, including goblet cell hyperplasia, reduction of cilia beating frequency, and endothelial activation, but did not alter rhinovirus infectivity or replication. High resolution kinetic analysis of secreted inflammatory markers revealed that IL-13 treatment altered the IL-6, IFN-{lambda}1, and CXCL10 secretion in response to HRV16. Neutrophil transepithelial migration was greatest when viral infection was combined with IL-13 treatment, while treatment with MK-7123, a CXCR2 antagonist, reduced neutrophil diapedesis in all conditions. ConclusionsThis micro-engineered Airway Lung-Chip provides a novel human-relevant platform for exploring the complex mechanisms underlying viral-induced asthma exacerbation. Our data suggest that IL-13 may impair the hosts ability to mount an appropriate and coordinated immune response to rhinovirus infection. We also show that the Airway Lung-Chip can be used to assess the efficacy of modulators of the immune response. NoteEmulate(R), Human Emulation System(R), S-1, ER-1, and ER-2 are trademarks of Emulate, Inc., and any other trademarks used herein remain with their respective holders. The technology disclosed in this document may be covered by one or more patents or patent applications, and no license to these is granted herein. You are solely responsible for determining whether you have all intellectual property rights that are necessary for your intended use of any of the disclosed materials, and whether you are required to obtain any additional intellectual property rights from a third party. Further information is available by contacting the authors. At a Glance CommentaryO_ST_ABSScientific Knowledge on the SubjectC_ST_ABSNew therapies for asthma exacerbations remain a significant unmet medical need. Development of human relevant preclinical models are needed to further elucidate the complex mechanisms underlying asthma exacerbation and investigate new therapeutic strategies. What This Study Adds to the FieldUsing a human Airway Lung-Chip model, we show here for the first time a live human rhinovirus (HRV) infection of the asthmatic epithelium that recapitulates complex features of viral-induced asthma exacerbation. The dynamic microenvironment of the chip enables the real-time study of virus infection, epithelial response, and immune cell recruitment under healthy and asthmatic conditions. The model reproduces key endpoints that have been observed in asthmatics and individuals infected with rhinovirus including the ciliated cell sloughing, altered cilia beating frequency, goblet cell hyperplasia, increased expression of adhesion molecules in microvascular endothelial cells, and inflammatory mediator release. High-resolution temporal analysis of secreted inflammatory markers enabled by dynamic sampling revealed alteration of IL-6, IFN-{lambda}1 and CXCL10 secretory phases after rhinovirus infection in an IL-13 high environment. Leveraging high-content imaging and analysis of circulating inflammatory cells, we demonstrated the efficacy of a CXCR2 antagonist to reduce adhesion, motility, and transmigration of perfused human neutrophils. Thus, this micro-engineered chip may offer a powerful addition to preclinical models for understanding mechanisms underlying asthma exacerbation pathology and developing new therapeutic strategies.

bioengineering↗

bioRxiv2019

Processing cookies formulated with goat cream enriched with conjugated linoleic acid

Goat fat is one of the most important sources of conjugated linoleic acid (CLA), a fatty acid which has health benefits. However, CLA consumption is limited to meats and milk products as CLA is generated in ruminants. This study aimed to replace vegetable fat by goat cream enriched with CLA. Four cookie recipes were developed with only the fat source being different: CVF - vegetable fat; CB - butter; CGC - goat cream without CLA; CGCLA - goat cream with CLA. Cookies were evaluated according to physical (color and texture) and physical-chemical parameters (lipids, proteins, total sugars, fiber, ash, moisture and Aw), Consumer Testing (n = 123) and lipid profile. The CGCLA presented higher values in the color parameters, and the higher and the lower scores in relation to hardness were 5.54 (CB) and 2.21 (CVF), respectively. Lipids and total sugars varied inversely, and the highest percentages of lipids were in the CVF and CG samples, which obtained lower total sugar content. There was no difference in the acceptance and preference of the four formulations, and the formulations with the goat creams (CG and CGCLA) were as accepted as CFV. The lipid profile of the cookies presented CFV with the highest percentage of trans fatty acids (TFA) with 16.76 %. CGCLA presented 70 % more CLA in relation to CB and CGC, thus certifying that CLA was present in relevant quantities in the CGCLA, even after cooking. The CGCLA is a biscuit with higher levels of CLA, and in this study it was possible to verify that the goat milk cream enriched with CLA can be used in producing cookies which adds functional and nutritional properties to them and offers other alternatives to produce food from goat's milk cream.

biochemistry↗