PM2.5, component cause of severe metabolically abnormal obesity: An in silico, observational and analytical study

Sagrario Lobato; A Lourdes Castillo-Granada; Marcos Bucio-Pacheco; Víctor Manuel Salomón-Soto; Ramiro Álvarez-Valenzuela; Perla Margarita Meza-Inostroza; Raúl Villegas-Vizcaíno

doi:10.1016/j.heliyon.2024.e28936

PM_2.5, component cause of severe metabolically abnormal obesity: An in silico, observational and analytical study

Heliyon. 2024 Apr 3;10(7):e28936. doi: 10.1016/j.heliyon.2024.e28936. eCollection 2024 Apr 15.

Authors

Sagrario Lobato^{1

2

3}, A Lourdes Castillo-Granada^{3

4}, Marcos Bucio-Pacheco^{3

5}, Víctor Manuel Salomón-Soto³, Ramiro Álvarez-Valenzuela³, Perla Margarita Meza-Inostroza³, Raúl Villegas-Vizcaíno³

Affiliations

¹ Departamento de Investigación en Salud, Servicios de Salud del Estado de Puebla, 15 South Street 302, Puebla, Mexico.
² Promoción y Educación para la Salud, Universidad Abierta y a Distancia de México. Universidad Avenue 1200, 1st Floor, quadrant 1-2, Xoco, Benito Juarez, 03330, Mexico City, Mexico.
³ Educación Superior, Centro de Estudios, "Justo Sierra", Surutato, Badiraguato, Mexico.
⁴ Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, Guelatao Avenue 66, Ejército de Oriente Indeco II ISSSTE, Iztapalapa, 09230, Mexico City, Mexico.
⁵ Facultad de Biología, Universidad Autónoma de Sinaloa, Americas Avenue, Universitarios Blvd., University City, 80040, Culiacán Rosales, Mexico.

Abstract

Obesity is currently one of the most alarming pathological conditions due to the progressive increase in its prevalence. In the last decade, it has been associated with fine particulate matter suspended in the air (PM_2.5). The purpose of this study was to explore the mechanistic interaction of PM_2.5 with a high-fat diet (HFD) through the differential regulation of transcriptional signatures, aiming to identify the association of these particles with metabolically abnormal obesity. The research design was observational, using bioinformatic methods and an explanatory approach based on Rothman's causal model. We propose three new transcriptional signatures in murine adipose tissue. The sum of transcriptional differences between the group exposed to an HFD and PM_2.5, compared to the control group, were 0.851, 0.265, and -0.047 (p > 0.05). The HFD group increased body mass by 20% with two positive biomarkers of metabolic impact. The group exposed to PM_2.5 maintained a similar weight to the control group but exhibited three positive biomarkers. Enriched biological pathways (p < 0.05) included PPAR signaling, small molecule transport, adipogenesis genes, cytokine-cytokine receptor interaction, and HIF-1 signaling. Transcriptional regulation predictions revealed CpG islands and common transcription factors. We propose three new transcriptional signatures: FAT-PM_2.5-CEJUS, FAT-PM_2.5-UP, and FAT-PM_2.5-DN, whose transcriptional regulation profile in adipocytes was statistically similar by dietary intake and HFD and exposure to PM_2.5 in mice; suggesting a mechanistic interaction between both factors. However, HFD-exposed murines developed moderate metabolically abnormal obesity, and PM_2.5-exposed murines developed severe abnormal metabolism without obesity. Therefore, in Rothman's terms, it is concluded that HFD is a sufficient cause of the development of obesity, and PM_2.5 is a component cause of severe abnormal metabolism of obesity. These signatures would be integrated into a systemic biological process that would induce transcriptional regulation in trans, activating obesogenic biological pathways, restricting lipid mobilization pathways, decreasing adaptive thermogenesis and angiogenesis, and altering vascular tone thus inducing a severe metabolically abnormal obesity.

Keywords: Airborne particulate matter; Causality; Metabolically abnormal obesity; Transcriptional signatures.