中文摘要：

盡管我們對斑馬魚心臟再生的理解取得了許多進展，但研究較少的一個方面是再生心肌細胞如何侵入和替代含有膠原蛋白的受傷組織。在這里，我們對心肌細胞侵襲的過程進行了深入分析。我們觀察到突出的邊界區心肌細胞和巨噬細胞之間的密切相互作用，并表明巨噬細胞對于傷口邊界區的細胞外基質重塑和心肌細胞突出到受傷區域至關重要。單細胞 RNA 測序揭示了編碼膜錨定基質金屬蛋白酶的 mmp14b 在邊界區的幾種細胞類型中的表達。遺傳性 mmp14b 突變導致巨噬細胞募集減少、膠原蛋白降解，隨后心肌細胞突出到受傷組織中。此外，心肌細胞特異性過表達 mmp14b 足以增強心肌細胞侵襲受傷組織和沿傷口頂端表面的滲透。總而言之，我們的數據為心臟再生過程中心肌細胞侵襲含膠原的受傷組織的機制提供了重要的見解。

英文摘要：

Despite numerous advances in our understanding of zebrafish cardiac regeneration, an aspect that remains less studied is how regenerating cardiomyocytes invade and replace the collagen-containing injured tissue. Here, we provide an in-depth analysis of the process of cardiomyocyte invasion. We observe close interactions between protruding border-zone cardiomyocytes and macrophages, and show that macrophages are essential for extracellular matrix remodeling at the wound border zone and cardiomyocyte protrusion into the injured area. Single-cell RNA-sequencing reveals the expression of mmp14b, encoding a membrane-anchored matrix metalloproteinase, in several cell types at the border zone. Genetic mmp14b mutation leads to decreased macrophage recruitment, collagen degradation, and subsequent cardiomyocyte protrusion into injured tissue. Furthermore, cardiomyocyte-specific overexpression of mmp14b is sufficient to enhance cardiomyocyte invasion into the injured tissue and along the apical surface of the wound. Altogether, our data provide important insights into the mechanisms underlying cardiomyocyte invasion of the collagen-containing injured tissue during cardiac regeneration.

論文信息：

論文題目：Border-zone cardiomyocytes and macrophages regulate extracellular matrix remodeling to promote cardiomyocyte protrusion during cardiac regeneration

期刊名稱：Nature Communications

時間期卷：16, Article number: 3823 (2025)

在線時間：2025年4月23日

DOI：doi.org/10.1038/s41467-025-59169-4

產品信息：

貨號：CP-005-005

規格：5ml+5ml

品牌：Liposoma

產地：荷蘭

名稱：Clodronate Liposomes and Control Liposomes

辦事處：Target Technology（靶點科技）

氯膦酸鹽脂質體斑馬魚巨噬細胞。斑馬魚心臟冷凍損傷后，多種細胞類型協調對損傷的反應。例如，內皮細胞、心內膜細胞和心外膜細胞已被證明可提供生長因子和信號分子，以促進受傷組織的血運重建和心肌細胞再生。成纖維細胞主要起源于心外膜，已被證明在心臟再生過程中沉積 ECM 以支持心臟，并且對損傷后心肌細胞增殖至關重要。近年來，免疫細胞在促進心臟再生過程中的重要性也得到了認可。特別是，巨噬細胞已被證明在斑馬魚、蠑螈和新生小鼠心臟的損傷再生中起著重要作用。巨噬細胞已被證明直接促進和調節冷凍損傷心臟中瘢痕/ECM 的組成。此外，氯膦酸鹽脂質體給藥（荷蘭Liposoma，清除巨噬細胞）或使用遺傳模型消耗巨噬細胞會導致 CM 增殖和再生心臟新生血管形成缺陷。雖然很明顯，許多（如果不是全部）心肌細胞類型在心臟再生過程中起著至關重要的作用，但它們對冷凍損傷后心肌細胞纖維化組織重新填充的貢獻在很大程度上是未知的。氯膦酸鹽二鈉脂質體清除巨噬細胞在斑馬魚心臟凍傷模型巨噬細胞功能研究，荷蘭Liposoma巨噬細胞清除劑Clodronate Liposomes見刊于Nature Communications：斑馬魚交界區心肌細胞和巨噬細胞調節細胞外基質重塑，促進心臟再生過程中心肌細胞突出。

Liposoma巨噬細胞清除劑Clodronate Liposomes氯膦酸二鈉脂質體的材料和方法：

Macrophage ablation

Ventricles from Tg(mpeg:NTR-YFP) adult fish were cryoinjured as described above. Cryoinjured fish were then incubated in a 5?μm nifurpirinol or DMSO-control water bath from 4 to 6 days following cryoinjury (replenished daily). Hearts were extracted at 7 dpci and subjected to immunostaining with GFP antibody to check macrophage ablation efficiency and phalloidin staining to quantify CM protrusion at the border zone as described above.

To ablate resident macrophages, Tg(mpeg1:EGFP) adult fish were IP injected with 10?μl clodronate liposomes (5?mg/ml) (Liposoma, Amsterdam, The Netherlands) or PBS 8 days prior to cryoinjury. Hearts were extracted at 7 or 10 dpci followed by cryosection, CHP staining, and phalloidin staining, as described above. Quantification of CHP intensity and CM protrusion at the border zone were performed as described above.

To ablate macrophages at later timepoints, Tg(mpeg1:EGFP) adult fish were IP injected with 10?μl clodronate liposomes (5?mg/ml) (Liposoma, Amsterdam, The Netherlands) or PBS control liposomes at 3, 6, and 9 dpci before collection of hearts at 10 dpci. To study the impact of macrophage ablation on mmp14b overexpression in CMs, Tg(hsp70l:loxP-EGFP-loxP-mmp14b-P2A-tagBFP); Tg(?5.1myl7:CreERT2) adult fish were IP injected with clodronate liposomes or PBS liposomes 1 day prior to cryoinjury and every 4 days afterwards. Tamoxifen/ethanol injections and heat shock were performed to induce mmp14b overexpression as described above. Hearts were extracted at 10 or 21 dpci followed by cryosection and phalloidin or MHC staining as described above. Quantification of CM protrusion at the border zone and CM cortical coverage were performed as described above.