BACKGROUND Ability to adapt to temperature changes trough the Heat Shock Response (HSR) pathways is one of the most fundamental and clinically relevant cellular response systems. Heat Shock (HS) affects the signalling and gene expression responses of the Nuclear Factor κB (NF-κB) transcription factor, a critical regulator of proliferation and inflammation, however, our quantitative understanding of how cells sense and adapt to temperature changes is limited. METHODS We used live-cell time-lapse microscopy and mathematical modelling to understand the signalling of the NF-κB system in the human MCF7 breast adenocarcinoma cells in response to pro-inflammatory Interleukin 1β (IL1β) and Tumour Necrosis Factor α (TNFα) cytokines, following exposure to a 37-43 °C range of physiological and clinical temperatures. RESULTS We show that exposure to 43 °C 1 h HS inhibits the immediate NF-κB signalling response to TNFα and IL1β stimulation although uptake of cytokines is not impaired. Within 4 h after HS treatment IL1β-induced NF-κB responses return to normal levels, but the recovery of the TNFα-induced responses is still affected. Using siRNA knock-down of Heat Shock Factor 1 (HSF1) we show that this stimulus-specificity is conferred via the Inhibitory κB kinase (IKK) signalosome where HSF1-dependent feedback regulates TNFα, but not IL1β-mediated IKK recovery post HS. Furthermore, we demonstrate that through the temperature-dependent denaturation and recovery of IKK, TNFα and IL1β-mediated signalling exhibit different temperature sensitivity and adaptation to repeated HS when exposed to a 37-43 °C temperature range. Specifically, IL1β-mediated NF-κB responses are more robust to temperature changes in comparison to those induced by TNFα treatment. CONCLUSIONS We demonstrate that the kinetics of the NF-κB system following temperature stress is cytokine specific and exhibit differential adaptation to temperature changes. We propose that this differential temperature sensitivity is mediated via the IKK signalosome, which acts as a bona fide temperature sensor trough the HSR cross-talk. This novel quantitative understanding of NF-κB and HSR interactions is fundamentally important for the potential optimization of therapeutic hyperthermia protocols. Video Abstract.

中文翻译：

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热休克反应调节促炎 NF-κB 信号传导的刺激特异性和敏感性。

背景技术通过热休克反应(HSR)途径适应温度变化的能力是最基本且临床相关的细胞反应系统之一。热休克 (HS) 会影响核因子 κB (NF-κB) 转录因子的信号传导和基因表达反应，核因子 κB 是增殖和炎症的关键调节因子，然而，我们对细胞如何感知和适应温度变化的定量理解是有限的。方法 我们使用活细胞延时显微镜和数学模型来了解人 MCF7 乳腺腺癌细胞中 NF-κB 系统响应促炎白细胞介素 1β (IL1β) 和肿瘤坏死因子 α (TNFα) 细胞因子的信号传导，暴露于 37-43 °C 的生理和临床温度范围后。结果我们发现暴露于 43 °C 1 h HS 会抑制对 TNFα 和 IL1β 刺激的即时 NF-κB 信号传导反应，尽管细胞因子的摄取并未受损。HS治疗后4小时内IL1β诱导的NF-κB反应恢复到正常水平，但TNFα诱导的反应的恢复仍然受到影响。利用 siRNA 敲低热休克因子 1 (HSF1)，我们发现这种刺激特异性是通过抑制性 κB 激酶 (IKK) 信号体赋予的，其中 HSF1 依赖性反馈调节 TNFα，但不调节 HS 后 IL1β 介导的 IKK 恢复。此外，我们证明，通过 IKK 的温度依赖性变性和恢复，TNFα 和 IL1β 介导的信号传导在暴露于 37-43 °C 温度范围时表现出不同的温度敏感性和对重复 HS 的适应。具体而言，与 TNFα 治疗诱导的反应相比，IL1β 介导的 NF-κB 反应对温度变化的反应更为强烈。结论 我们证明 NF-κB 系统在温度应激后的动力学具有细胞因子特异性，并且表现出对温度变化的差异适应。我们认为这种温差敏感性是通过 IKK 信号体介导的，IKK 信号体通过 HSR 串扰充当真正的温度传感器。这种对 NF-κB 和 HSR 相互作用的新颖定量理解对于热疗方案的潜在优化至关重要。视频摘要。