Abstract

Hyperthermia is a potentially lethal side-effect of Methamphetamine (Meth), a stimulant drug. Activation of non-shivering thermogenesis in brown adipose tissue (BAT) is partly responsible for Meth-induced rise in temperature, with contributing sympathetic neurotransmitters, such as norepinephrine (NE), and reactive oxygen species (ROS). However, the mechanisms controlling the development of a molecular thermogenic program in brown adipocytes (BA) following Meth are unknown. We hypothesize that Meth and NE affect BAT cells, BA and macrophages, to modify their physiology and interactions, with consequences to thermogenic genes. We also hypothesize that ROS play a critical role in signaling transcription of thermogenic genes and their regulatory components. Using primary BA and macrophage cultures, we measured Meth and NE interference with physiological and phenotypic measures that are relevant to thermogenesis in BAT. Meth caused both BA and macrophages to decrease mitochondrial maximal capacity and increase ROS. In BA, the thermogenic genes UCP1, PPARγ, PGC1α and GADD45γ were transcriptionally increased by Meth in a ROS-dependent manner. In macrophages, Meth increased oxidative stress response and caused a predominance of M2 subset markers. BA transcriptional changes in response to Meth and NE were significantly controlled by macrophages. The results suggest that BA and macrophages respond to Meth and NE, with effects on mitochondrial functions and transcription of genes involved in thermogenesis. ROS-dependent signals in BA and cellular interactions between BA and macrophages synergize to regulate the BAT environment and control critical pathways leading to Meth-hyperthermia.

摘要

热疗是兴奋剂药物甲基苯丙胺 (Meth) 的潜在致命副作用。棕色脂肪组织 (BAT) 中非颤抖产热的激活是甲基苯丙胺诱导的温度升高的部分原因，并有助于交感神经递质，如去甲肾上腺素 (NE) 和活性氧 (ROS)。然而，控制甲基苯丙胺后棕色脂肪细胞 (BA) 中分子产热程序发展的机制尚不清楚。我们假设 Meth 和 NE 会影响 BAT 细胞、BA 和巨噬细胞，以改变它们的生理和相互作用，从而对产热基因产生影响。我们还假设 ROS 在产热基因及其调控成分的信号转导中起关键作用。使用初级 BA 和巨噬细胞培养物，我们测量了 Meth 和 NE 对与 BAT 产热相关的生理和表型测量的干扰。Meth 导致 BA 和巨噬细胞降低线粒体最大容量并增加 ROS。在BA中，产热基因UCP1、PPARγ、PGC1α和GADD45γ被Meth以ROS依赖性方式转录增加。在巨噬细胞中，Meth 增加了氧化应激反应并导致 M2 子集标记物占优势。响应于 Meth 和 NE 的 BA 转录变化受到巨噬细胞的显着控制。结果表明，BA 和巨噬细胞对 Meth 和 NE 有反应，影响线粒体功能和参与产热的基因转录。