Lymphatic muscle cells are the innate pacemaker cells regulating mouse lymphatic collecting vessel contractions.
Lymphatic muscle cells are the innate pacemaker cells regulating mouse lymphatic collecting vessel contractions.
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淋巴肌细胞是调节小鼠淋巴集合管收缩的先天起搏细胞。
DOI：
10.1101/2023.08.24.554619
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Davis,MJ
中科院分区：
文献类型：
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作者：
Zawieja,SD;Pea,GA;Broyhill,SE;Bromert,KH;Norton,CE;Kim,HJ;Li,M;Castorena-Gonzalez,JA;Drumm,BT;Davis,MJ
收集淋巴管（clv）表现出具有压力依赖性频率的自发收缩，但淋巴起搏器细胞的身份仍然存在争议。与胃肠道和下尿路的起搏器类似，建议的cLV起搏器细胞包括Cajal样细胞（ICLC）的间质细胞或淋巴肌（LMCs）细胞本身。在这里，我们将免疫荧光和scRNAseq分析与电生理方法结合起来，检查小鼠cLV壁的细胞成分，并评估是否有任何类型的细胞表现出起搏器细胞的形态和功能过程特征：一个连续的（如果不是连续的）整合到电合胞体中的网络；自发Ca2+瞬态；以及去极化引起的传播性收缩。我们采用常规的诱导Cre （iCre）小鼠模型来靶向这些特定的细胞群，包括：c-kitCreERT2靶向ICLC；PdgfrβCreERT2靶向周细胞样细胞；PdgfrαCreER™靶向CD34+上皮细胞和ICLC；和Myh11CreERT2直接针对lmc。这些特异的可诱导Cre系与荧光报告基因ROSA26mT/mG、基因编码的Ca2+传感器GCaMP6f和光激活阳离子通道rhodopsin2 （ChR2）杂交。c-KitCreERT2标记了稀疏的lec群体和圆形外表皮细胞，这些细胞对肥大细胞激活剂化合物48-80有反应。PdgfrβCreERT2驱动外体细胞和lmc的重组，限制了其区分周细胞特异性群体的能力。PdgfrαCreER™标记了主要沿着血管外表面的大量相互连接的橡树叶状细胞。在这些细胞中，只有lmc在收缩周期的舒张期一致但异质性地表现出自发的Ca2+事件，其频率以压力依赖的方式调节。在Myh11CreERT2而非PdgfrαCreER™或c-KitCreERT2的控制下，通过ChR2表达的光遗传去极化导致光刺激下的扩散性收缩。lmc的膜电位记录显示，舒张期去极化速率与收缩频率显著相关。这些发现支持了lmc或lmc的一个子集负责小鼠cLV起搏的结论。
Collecting lymphatic vessels (cLVs) exhibit spontaneous contractions with a pressure-dependent frequency, but the identity of the lymphatic pacemaker cell is still debated. By analogy to pacemakers in the GI and lower urinary tracts, proposed cLV pacemaker cells include interstitial cells of Cajal like cells (ICLC) or the lymphatic muscle (LMCs) cells themselves. Here we combined immunofluorescence and scRNAseq analyses with electrophysiological methods to examine the cellular constituents of the mouse cLV wall and assess whether any cell type exhibited morphological and functional processes characteristic of pacemaker cells: a continuous if not contiguous network integrated into the electrical syncytium; spontaneous Ca2+ transients; and depolarization-induced propagated contractions. We employed inducible Cre (iCre) mouse models routinely used to target these specific cell populations including: c-kitCreERT2 to target ICLC; PdgfrβCreERT2 to target pericyte-like cells; PdgfrαCreER™ to target CD34+ adventitial cells and ICLC; and Myh11CreERT2 to target LMCs directly. These specific inducible Cre lines were crossed to the fluorescent reporter ROSA26mT/mG, the genetically encoded Ca2+ sensor GCaMP6f, and the light-activated cation channel rhodopsin2 (ChR2). c-KitCreERT2 labeled both a sparse population of LECs and round adventitial cells that responded to the mast cell activator compound 48–80. PdgfrβCreERT2 drove recombination in both adventitial cells and LMCs, limiting its power to discriminate a pericyte-specific population. PdgfrαCreER™ labeled a large population of interconnected, oak leaf-shaped cells primarily along the adventitial surface of the vessel. Of these cells, only LMCs consistently, but heterogeneously, displayed spontaneous Ca2+ events during the diastolic period of the contraction cycle, and whose frequency was modulated in a pressure-dependent manner. Optogenetic depolarization through the expression of ChR2 under control of Myh11CreERT2, but not PdgfrαCreER™ or c-KitCreERT2, resulted in propagated contractions upon photo-stimulation. Membrane potential recordings in LMCs demonstrated that the rate of diastolic depolarization significantly correlated with contraction frequency. These findings support the conclusion that LMCs, or a subset of LMCs, are responsible for mouse cLV pacemaking.