Fibroblast PER2 circadian rhythmicity depends on cell density.
Fibroblast PER2 circadian rhythmicity depends on cell density.
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DOI：
10.1177/0748730413487494
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发表时间：
2013-06
影响因子：
3.5
通讯作者：
Welsh DK
中科院分区：
文献类型：
--
作者：
Noguchi T;Wang LL;Welsh DK
就像视交叉上核（SCN）中的神经元（大脑中主要的昼夜节律起搏器）一样，单个成纤维细胞可以充当独立的振荡器。在 SCN 中，细胞间的突触和旁分泌信号传导产生强大的、同步的昼夜节律振荡，而在成纤维细胞培养物中没有证据表明这种整合。然而，不能完全排除单细胞成纤维细胞振荡器之间的相互作用，因为在之前的工作中并未分离出成纤维细胞。在这项研究中，我们通过对 PER2::LUC 昼夜节律报告小鼠的细胞进行单细胞成像，测试了高密度和低密度培养物中成纤维细胞作为单细胞昼夜节律振荡器的自主性。我们发现低密度培养物中 PER2::LUC 节律性大大降低，这可能是由于邻近成纤维细胞缺乏组成型或节律性旁分泌信号所致。为了区分这两种可能性，我们将 PER2::LUC 野生型 (WT) 细胞与不发光、非节律性 Bmal1−/− 细胞混合，这样节律性细胞的密度较低，但总体细胞密度仍然较高。在这种情况下，WT 细胞表现出与高密度培养物相似的清晰节律性。我们还将 PER2::LUC WT 细胞与不发光、长周期 Cry2−/− 细胞混合。在这种情况下，WT细胞表现出的周期与用节律性WT细胞或非节律性Bmal1−/−细胞培养的细胞没有什么不同。在之前的工作中，我们发现低K+抑制成纤维细胞节律性，我们和其他人发现低K+或低Ca2+抑制SCN节律性。因此，我们尝试用高 K+ (21 mM)、高 Ca2+ (3.6 mM) 或条件培养基来挽救低密度成纤维细胞的节律性。来自高密度成纤维细胞培养物的条件培养基挽救了低密度培养物的节律性，而高K+或Ca2+培养基并不能一致地挽救节律性。这些数据表明，成纤维细胞需要来自邻近细胞的旁分泌信号来正常表达节律性，但这些信号不一定是有节律的，并且来自其他细胞的节律信号不会影响成纤维细胞的固有周期。
Like neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in the brain, single fibroblasts can function as independent oscillators. In the SCN, synaptic and paracrine signaling among cells creates a robust, synchronized circadian oscillation, whereas there is no evidence for such integration in fibroblast cultures. However, interactions among single-cell fibroblast oscillators cannot be completely excluded, because fibroblasts were not isolated in previous work. In this study, we tested the autonomy of fibroblasts as single-cell circadian oscillators in high and low density culture, by single-cell imaging of cells from PER2::LUC circadian reporter mice. We found greatly reduced PER2::LUC rhythmicity in low density cultures, which could result from lack of either constitutive or rhythmic paracrine signals from neighboring fibroblasts. To discriminate between these two possibilities, we mixed PER2::LUC wild type (WT) cells with non-luminescent, non-rhythmic Bmal1−/− cells, so that density of rhythmic cells was low but overall cell density remained high. In this condition, WT cells showed clear rhythmicity similar to high density cultures. We also mixed PER2::LUC WT cells with non-luminescent, long period Cry2−/− cells. In this condition, WT cells showed a period no different from cells cultured with rhythmic WT cells or non-rhythmic Bmal1−/− cells. In previous work, we found that low K+ suppresses fibroblast rhythmicity, and we and others have found that either low K+ or low Ca2+ suppresses SCN rhythmicity. Therefore, we attempted to rescue rhythmicity of low density fibroblasts with high K+ (21 mM), high Ca2+ (3.6 mM), or conditioned medium. Conditioned medium from high density fibroblast cultures rescued rhythmicity of low density cultures, whereas high K+ or Ca2+ medium did not consistently rescue rhythmicity. These data suggest that fibroblasts require paracrine signals from adjacent cells for normal expression of rhythmicity, but that these signals do not have to be rhythmic, and that rhythmic signals from other cells do not affect the intrinsic periods of fibroblasts.
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影响因子：
3.5
作者：
Noguchi T;Ikeda M;Ohmiya Y;Nakajima Y
通讯作者：
Nakajima Y
影响因子：
3.3
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Liu AC;Tran HG;Zhang EE;Priest AA;Welsh DK;Kay SA
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作者：
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影响因子：
5.3
作者：
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通讯作者：
Herzog, ED