Publications by authors named "Marcus Alvarez"

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by an excess of lipids, mainly triglycerides, in the liver and components of the metabolic syndrome, which can lead to cirrhosis and liver cancer. While there is solid epidemiological evidence that MASLD clusters with cardiometabolic disease, several leading genetic risk factors for MASLD do not increase the risk of cardiovascular disease, suggesting no causal relationship between MASLD and cardiometabolic derangement. In this work, we leveraged measurements of visceral adiposity identifying 27 previously unknown genetic loci associated with MASLD (n = 36,394), six replicated in four independent cohorts (n = 3,903).

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Given the fast-increasing prevalence of obesity and its comorbidities, it would be critical to improve our understanding of the cell-type level differences between the two key human adipose tissue depots, subcutaneous (SAT) and visceral adipose tissue (VAT), in their depot-specific contributions to cardiometabolic health. We integrated cell-type level RNA- and ATAC-seq data from human SAT and VAT biopsies and cell-lines to comprehensively elucidate transcriptomic, epigenetic, and genetic differences between the two fat depots. We identify cell-type marker genes for tissue specificity and functional enrichment, and show through genome-wide association study (GWAS) and partitioned polygenic risk score (PRS) enrichment analyses that the marker genes upregulated in SAT adipocytes have more prominent roles in abdominal obesity than those of VAT.

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Human subcutaneous adipose tissue (SAT) contains a diverse array of cell-types; however, the epigenomic landscape among the SAT cell-types has remained elusive. Our integrative analysis of single-cell resolution DNA methylation and chromatin conformation profiles (snm3C-seq), coupled with matching RNA expression (snRNA-seq), systematically cataloged the epigenomic, 3D topology, and transcriptomic dynamics across the SAT cell-types. We discovered that the SAT CG methylation (mCG) landscape is characterized by pronounced hyper-methylation in myeloid cells and hypo-methylation in adipocytes and adipose stem and progenitor cells (ASPCs), driving nearly half of the 705,063 detected differentially methylated regions (DMRs).

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  • Research on abdominal obesity highlighted that the rs10494217 variant in the TBX15 gene is linked to adipocyte health and the heritability of obesity.
  • The frequency of this variant shows a geographical trend, decreasing from north to south, particularly evident in the Finnish population, suggesting an adaptive response to colder climates.
  • Individuals with the risk allele exhibit changes in gene expression related to thermogenesis and unhealthy fat cell growth, indicating the variant's possible role in promoting abdominal obesity.
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and are responsible for transmitting major human arboviruses such as Dengue, Zika, and Chikungunya, posing a global threat to public health. The lack of etiological treatments and efficient vaccines makes vector control strategies essential for reducing vector population density and interrupting the pathogen transmission cycle. This study evaluated the impact of long-term pyriproxyfen exposure on the genetic structure and diversity of and mosquito populations.

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Taking into consideration that bees can be contaminated by pesticides through the ingestion of contaminated floral resources, we can utilize genetic techniques to assess effects that are scarcely observed in behavioral studies. This study aimed to investigate the genetic effects of ingesting lethal and sublethal doses of the insecticide fipronil in foraging honey bees during two periods of acute exposure. Bees were exposed to fipronil through contaminated honey syrup at two dosages (LD = 0.

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  • Abdominal obesity is linked to an increased risk of metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD).
  • The study employed advanced genetic analysis methods, including RNA sequencing and Mendelian randomization, to explore how specific genes related to abdominal obesity impact MASLD at the cellular level.
  • The research identified 17 key genes that mediate the effects of abdominal obesity on MASLD, demonstrating significant changes in adipocyte functions and highlighting the importance of these genes in the disease's development.
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Bees are important pollinators for ecosystems and agriculture; however, populations have suffered a decline that may be associated with several factors, including habitat loss, climate change, increased vulnerability to diseases and parasites and use of pesticides. The extensive use of neonicotinoids, including imidacloprid, as agricultural pesticides, leads to their persistence in the environment and accumulation in bees, pollen, nectar, and honey, thereby inducing deleterious effects. Forager honey bees face significant exposure to pesticide residues while searching for resources outside the hive, particularly systemic pesticides like imidacloprid.

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Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses an excess of triglycerides in the liver, which can lead to cirrhosis and liver cancer. While there is solid epidemiological evidence of MASLD coexisting with cardiometabolic disease, several leading genetic risk factors for MASLD do not increase the risk of cardiovascular disease, suggesting no causal relationship between MASLD and cardiometabolic derangement. In this work, we leveraged measurements of visceral adiposity and identified 27 novel genetic associated with MASLD.

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Background: Age and obesity are dominant risk factors for several common cardiometabolic disorders, and both are known to impair adipose tissue function. However, the underlying cellular and genetic factors linking aging and obesity on adipose tissue function have remained elusive. Adipose stem and precursor cells (ASPCs) are an understudied, yet crucial adipose cell type due to their deterministic adipocyte differentiation potential, which impacts the capacity to store fat in a metabolically healthy manner.

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Biobanks that collect deep phenotypic and genomic data across many individuals have emerged as a key resource in human genetics. However, phenotypes in biobanks are often missing across many individuals, limiting their utility. We propose AutoComplete, a deep learning-based imputation method to impute or 'fill-in' missing phenotypes in population-scale biobank datasets.

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  • Genetic diversity and population structure of a sylvatic vector for yellow fever virus in São Paulo vary based on agricultural land use and isolation of Atlantic Forest fragments.
  • High genetic diversity is found in areas with intense agricultural activity, while populations show signs of recent expansion, indicated by negative values in neutrality tests.
  • A strong correlation exists between population structuring and the spatial distance of sampled forest fragments, with coastal populations being more closely related than those in the northwest.
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  • Understanding how different gene expressions in fat tissue relate to cardiometabolic diseases can help identify potential health risks.
  • Researchers analyzed 859 adipose tissue samples, revealing that specific cell types, like macrophages and adipocytes, influence traits like body mass index (BMI).
  • The study found that including both BMI and cell type in analysis models led to the identification of 2,664 significant gene-trait associations, highlighting the need to consider cell diversity in genetic assessments related to metabolism.
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  • Researchers studied the gene expression of adipocytes (fat cells) in both subcutaneous fat and heart tissue to understand their roles in cardiovascular health.
  • The study revealed unique characteristics and functional pathways for heart-resident adipocytes, including the discovery of the propanoate metabolism pathway.
  • Findings indicate that heart adipocytes have specific gene markers linked to coronary artery disease risk and show more communication pathways in the atria compared to the ventricles.
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Background: Non-alcoholic fatty liver disease (NAFLD) is a fast-growing, underdiagnosed, epidemic. We hypothesise that obesity-related inflammation compromises adipose tissue functions, preventing efficient fat storage, and thus driving ectopic fat accumulation into the liver.

Methods: To identify adipose-based mechanisms and potential serum biomarker candidates (SBCs) for NAFLD, we utilise dual-tissue RNA-sequencing (RNA-seq) data in adipose tissue and liver, paired with histology-based NAFLD diagnosis, from the same individuals in a cohort of obese individuals.

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Context: The neutral amino acid transporter SLC7A10/ASC-1 is an adipocyte-expressed gene with reduced expression in insulin resistance and obesity. Inhibition of SLC7A10 in adipocytes was shown to increase lipid accumulation despite decreasing insulin-stimulated uptake of glucose, a key substrate for de novo lipogenesis. These data imply that alternative lipogenic substrates to glucose fuel continued lipid accumulation during insulin resistance in obesity.

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Single-nucleus RNA sequencing (snRNA-seq) provides a powerful tool for studying cell type composition in heterogenous tissues. The liver is a vital organ composed of a diverse set of cell types; thus, single-cell technologies could greatly facilitate the deconvolution of liver tissue composition and various downstream omics analyses at the cell-type level. Applying single-cell technologies to fresh liver biopsies can, however, be very challenging, and snRNA-seq of snap-frozen liver biopsies requires some optimization given the high nucleic acid content of the solid liver tissue.

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is a sylvatic vector species in Brazil. In We aimed to characterize the discrete typing units (DTUs), the parasitic loads, and the blood meal sources of insects collected in rocky outcrops in rural areas in the state of Minas Gerais. An optical microscope (OM) and kDNA-PCR were used to examine natural infection by , and positive samples were genotyped by conventional multilocus PCR.

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  • Common SNPs may account for 40-50% of human height variation, and this study identifies 12,111 SNPs linked to height from a large sample of 5.4 million individuals.
  • These SNPs cluster in 7,209 genomic segments, encompassing about 21% of the genome and showing varying densities enriched in relevant genes.
  • While these SNPs explain a substantial portion of height variance in European populations (40-45%), their predictive power is lower (10-24%) in other ancestries, suggesting a need for more research to enhance understanding in diverse populations.
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Exercise training is critical for the prevention and treatment of obesity, but its underlying mechanisms remain incompletely understood given the challenge of profiling heterogeneous effects across multiple tissues and cell types. Here, we address this challenge and opposing effects of exercise and high-fat diet (HFD)-induced obesity at single-cell resolution in subcutaneous and visceral white adipose tissue and skeletal muscle in mice with diet and exercise training interventions. We identify a prominent role of mesenchymal stem cells (MSCs) in obesity and exercise-induced tissue adaptation.

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In high abundance, females of the genus Mansonia (Blanchard) can be a nuisance to humans and animals because they are voraciously hematophagous and feed on the blood of a myriad of vertebrates. The spatial-temporal distribution pattern of Mansonia species is associated with the presence of their host plants, usually Eichhornia crassipes, E. azurea, Ceratopteris pteridoides, Limnobium laevigatum, Pistia stratiotes, and Salvinia sp.

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Obesity perturbs central functions of human adipose tissue, centred on differentiation of preadipocytes to adipocytes, i.e., adipogenesis.

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  • Hepatocellular carcinoma (HCC) is a primary liver cancer linked to poor survival rates, prompting research into cell-types that may impact patient outcomes.
  • Researchers utilized advanced sequencing techniques to analyze the differences in cell-types among HCC tumors, adjacent non-tumor tissues, and healthy liver samples from multiple medical centers.
  • A key finding was the identification of a tumor-associated proliferative cell-type, named Prol, which was found to be prevalent in HCC tissues, enriched in genes related to cell division, and correlated with lower survival rates for patients.
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