Exposure to PCB52 (2,2',5,5'-tetrachlorobiphenyl) blunts induction of the gene for uncoupling protein 1 (UCP1) in white adipose

Environ Toxicol Pharmacol. 2024 Dec 12:104612. doi: 10.1016/j.etap.2024.104612. Online ahead of print.

Abstract

Polychlorinated biphenyls (PCBs) are linked to cancer, learning disabilities, liver and cardiovascular disease, and diabetes. Older schools often contain high levels of PCBs, and inhalation is a major source of exposure. Technical PCB mixtures, called Aroclors, and individual dioxin-like PCBs impair adipocyte function, which can lead to type II diabetes. To determine how PCB52, a non-dioxin like PCB congener found in school air, affects adipose, adolescent male and female rats were exposed to PCB52 by nose-only inhibition for 4h per day for 28 consecutive days. Transcriptomic analysis of white adipose revealed sex-specific differences in gene expression between PCB52- and sham-exposed males and females. Exposed females showed mitochondrial gene changes, including downregulation of the thermogenic uncoupling gene, Ucp1. Human preadipocytes/adipocytes exposed to PCB52 or its main metabolite, 4-OH-PCB52, also showed reduced norepinephrine-induced UCP1 expression. These findings suggest that PCB52 inhalation disrupts thermogenesis in adipose tissue, potentially contributing to metabolic syndrome.

Keywords: PCB52; PCBs; UCP1, thermogenesis, metabolic syndrome; adipose.