Supplemental O₂ (hyperoxia) is necessary for preterm infant survival but is associated with development of bronchial airway hyperreactivity and childhood asthma. Understanding early mechanisms that link hyperoxia to altered airway structure and function are key to developing advanced therapies. We previously showed that even moderate hyperoxia (50% O₂) enhances intracellular calcium ([Ca²⁺]_i) and proliferation of human fetal airway smooth muscle (fASM), thereby facilitating bronchoconstriction and remodeling. Here, we introduce cellular clock biology as a novel mechanism linking early oxygen exposure to airway biology. Peripheral, intracellular clocks are a network of transcription-translation feedback loops that produce circadian oscillations with downstream targets highly relevant to airway function and asthma. Premature infants suffer circadian disruption while entrainment strategies improve outcomes, highlighting the need to understand relationships between clocks and developing airways. We hypothesized that hyperoxia impacts clock function in fASM and that the clock can be leveraged to attenuate deleterious effects of O₂ on the developing airway. We report that human fASM express core clock machinery (PER1, PER2, CRY1, ARNTL/BMAL1, CLOCK) that is responsive to dexamethasone and altered by O₂. Disruption of the clock via siRNA-mediated PER1 or ARNTL knockdown alters store-operated calcium entry (SOCE) and [Ca²⁺]_i response to histamine in hyperoxia. Effects of O₂ on [Ca²⁺]_i are rescued by driving expression of clock proteins, via effects on the Ca²⁺ channels IP₃R and Orai1. These data reveal a functional fASM clock that modulates [Ca²⁺]_i regulation, particularly in hyperoxia. Harnessing clock biology may be a novel therapeutic consideration for neonatal airway diseases following prematurity.

中文翻译：

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高氧中的细胞时钟对人体气道平滑肌发育过程中 [Ca2+]i 调节的影响

补充 O ₂（高氧）是早产儿存活所必需的，但与支气管气道高反应性和儿童哮喘的发展有关。了解将高氧与气道结构和功能改变联系起来的早期机制是开发先进疗法的关键。我们之前表明，即使是中度高氧 (50% O ₂ ) 也会增强细胞内钙 ([Ca ²⁺ ] _i) 和人胎儿气道平滑肌 (fASM) 的增殖，从而促进支气管收缩和重塑。在这里，我们将细胞时钟生物学作为一种将早期氧气暴露与气道生物学联系起来的新机制。外周细胞内时钟是一个转录-翻译反馈回路网络，可产生昼夜节律振荡，下游靶标与气道功能和哮喘高度相关。早产儿的昼夜节律紊乱，而夹带策略可改善结果，突出了了解生物钟与发育中的气道之间关系的必要性。我们假设高氧会影响 fASM 中的时钟功能，并且可以利用时钟来减弱 O _{2的有害影响}在发育中的气道上。我们报告人类 fASM 表达对地塞米松有反应并被 O ₂改变的核心时钟机制（PER1、PER2、CRY1、ARNTL/BMAL1、CLOCK） 。通过 siRNA 介导的 PER1 或 ARNTL 敲低破坏时钟会改变钙库操作的钙进入 (SOCE) 和 [Ca ²⁺ ] _i在高氧中对组胺的反应。O ₂对[Ca ²⁺ ] _i的影响通过驱动时钟蛋白的表达来挽救，通过对Ca ²⁺通道IP ₃ R 和Orai1 的影响。这些数据揭示了调节 [Ca ²⁺ ] _{i的功能性 fASM 时钟}调节，特别是在高氧时。利用时钟生物学可能是早产后新生儿气道疾病的一种新的治疗考虑。