Biology subjects

Tovar, A. R.

Publications and source records attributed to Tovar, A. R..

4 recordsLinked to original sources

bioRxiv2025

MICOMWeb: a website for microbial community metabolic modeling of the human gut

SummaryMICOMWeb is a user-friendly website for easy microbial community metabolic modeling of the human gut. This website tackles three constraints when generating in silico metagenome-scale metabolic models: (i) the prior Python user knowledge for metabolic modeling using flux balance analysis with MICOM Python package, (ii) predefined and user-defined diets to generate ad hoc metabolic models, and (iii) the high- throughput computational infrastructure required to obtain the simulated growth and metabolic exchange fluxes, using real abundance from metagenomic shotgun or 16S amplicon sequencing; we present MICOMWebs features to easily run in silico experiments as a functional hypothesis generator for experimental validation on previously published data. Availability and ImplementationMICOMWeb is freely accessible for academic purposes at https://micomweb.c3.unam.mx.

systems biology↗

bioRxiv2024

Metabolic reprogramming and synergistic cytotoxicity of genistein and chemotherapy in human breast cancer cells

Breast cancer (BCa) is a heterogeneous disease, initially responsive to hormone therapy but often developing resistance to both hormonal and chemotherapy treatments. Novel therapeutic strategies are needed for drug-resistant BCa. Genistein, a phytoestrogen structurally similar to estrogen, competes with estrogen for receptor binding and exhibits anti-cancer effects. In this study, we investigated the cellular and metabolic impacts of genistein, alone or in combination with chemotherapy, in two human BCa cell lines--one estrogen receptor-positive (ER+) and one estrogen receptor-negative (ER-). We observed a strong synergistic effect on cell viability at low concentrations of genistein and chemotherapy, resulting in reduced clonogenic capacity and impaired cell migration. Genistein alone modulated cellular energy metabolism, notably reducing ATP production in MCF7 (ER+) cells. This metabolic shift was linked to a decreased dependence on fatty acids for energy, coupled with a decrease in the rate-limiting mitochondrial translocase CPT1 required for fatty acid oxidation, alongside with an increase in intracellular fatty acid levels. While the most significant changes occurred in ER+ cells, ER- cells also showed responses to genistein treatment. Collectively, our findings suggest that low dose genistein, in combination with conventional chemotherapy, induces synergistic anti-cancer effects, promoting cellular senescence. This effect may be partly mediated by a reduced reliance on fatty acid metabolism in BCa cells.

cancer biology↗

bioRxiv2024

A three-country analysis of the gut microbiome indicates taxon associations with diet vary by location and strain

Emerging research suggests that diet plays a vital role in shaping the composition and function of the gut microbiota. While significant efforts have been made to identify general patterns linking diet to the gut microbiome, much of this research lacks representation from low- and middle-income countries such as Mexico. Additionally, both diet and the gut microbiome have highly complex and individualized configurations, and there is growing evidence that tailoring diets to individual gut microbiota profiles may optimize the path toward improving or maintaining health and preventing disease. Using fecal metagenomic data from 1,291 individuals across three countries, we examine two bacterial genera prevalent in the human gut, Prevotella and Faecalibacterium, which have gained significant attention due to their potential roles in human health. We find that they show significant associations with many aspects of diet, but that these associations vary in scale and direction, depending on the level of metagenomic resolution and the contextual population. These results highlight the growing importance of assembling metagenomic datasets that are standardized, comprehensive, and representative of diverse populations to increase our ability to tease apart the complex relationship between diet and the microbiome.

microbiology↗

bioRxiv2021

Coordination between metabolic transitions and gene expression by NAD+ availability during adipogenic differentiation in human cells.

Adipocytes are the main cell type in adipose tissue, a critical regulator of metabolism, highly specialized in storing energy as fat. Adipocytes differentiate from multipotent mesenchymal stromal cells through adipogenesis, a tightly controlled differentiation process involving closely interplay between metabolic transitions and sequential programs of gene expression. However, the specific gears driving this interplay remain largely obscure. Additionally, the metabolite nicotinamide adenine dinucleotide (NAD+) is becoming increasingly recognized as a regulator of lipid metabolism, being postulated as promising therapeutic target for dyslipidemia and obesity. Here, we explored the effect of manipulating NAD+ bioavailability during adipogenic differentiation from human mesenchymal stem cells. We found a previously unappreciated strong repressive role for NAD+ on adipocyte commitment, while a functional NAD+-dependent deacetylase SIRT1 appeared crucial for terminal differentiation of pre-adipocytes. Remarkably, repressing the NAD+ biosynthetic salvage pathway during adipogenesis promoted the adipogenic transcriptional program, suggesting that SIRT1 activity during adipogenesis is independent from the NAD+ salvage pathway, while two photon microscopy and extracellular flux analyses suggest that its activation relies on the metabolic switch. Interestingly, SIRT1-directed control of subcellular compartmentalization of redox metabolism during adipogenesis was evidenced by two-photon fluorescence lifetime microscopy. Significance StatementAdipocyte differentiation occurs from mesenchymal stem cells through the adipogenic process, involving sequential activation of both transcriptional and metabolic programs in a tightly coordinated manner. However, how transcriptional and metabolic transitions reciprocally interact during adipogenic differentiation remains largely obscure. Here we describe that the metabolite NAD+ is suppresses adipogenesis trough rewiring transcription, while a functional NAD+-dependent deacetylase SIRT1 is essential for terminal differentiation of pre-adipocytes. Using two-photon fluorescence lifetime microscopy, we created a metabolic map of NADH and lipid content simultaneously in live cells and described a new role for SIRT1 in the control of compartmentalization of redox metabolism during adipogenesis. These findings advance our understanding to improve therapeutical approaches targeting the NAD+-SIRT1 axis as treatment for obesity and dyslipemia.

cell biology↗