Our overview covers several key areas related to recent results obtained for collagen type VI and endotrophin (ETP). (1) An introduction to the history of ETP, including how it was identified, how it is released, and its function and potential receptors. (2) An introduction to the collagen family, with a focus on what differentiates collagen type VI from an evolutionary standpoint. (3) An overview of collagen type VI, the 6 individual chains (COL6A1, A2, A3, A4, A5, and A6), their differences and similarities, as well as their expression profiles and function. (4) A detailed analysis of COL6A3, including the cleaved product endotrophin, and what separates it from the other 5 collagen 6 molecules, including its suggested function based on insights gained from knockout and gain of function mouse models. (5) The pathology of ETP. What leads to its presence and release and what are the consequences thereof? (6) Functional implications of circulating ETP. Here we review the data with the functional roles of ETP in mind. (7) We propose that ETP is a mediator for fibrotic (or fibroinflammatory) disorders. Based on what we know about ETP, we have to consider it as a target for the treatment of fibrotic (or fibroinflammatory) disorders. What segment(s) of the patient population would most dramatically respond to an ETP-targeted intervention? How can we find the population that would profit most from an intervention? We aim to present a broad overview over the ETP field at large, providing an assessment of where the future research efforts need to be placed to tap into the vast potential of ETP, both as a marker and as a target in different diseases.

中文翻译：

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内营养因子，纤维炎症性疾病的关键标志物和驱动因素。


我们的概述涵盖了与 VI 型胶原蛋白和内养蛋白 （ETP） 的最新结果相关的几个关键领域。（1） ETP 的历史简介，包括它是如何识别的、如何释放的，以及它的功能和潜在的受体。（2） 胶原蛋白家族简介，重点介绍从进化角度区分 VI 型胶原蛋白的区别。（3） VI 型胶原蛋白、6 条独立链（COL6A1、A2、A3、A4、A5 和 A6）的概述，它们的异同，以及它们的表达谱和功能。（4） 对 COL6A3 的详细分析，包括裂解的产物内营养因子，以及它与其他 5 种胶原蛋白 6 分子的区别，包括根据从敲除和功能获得小鼠模型中获得的见解建议的功能。（5） ETP 的病理学。是什么导致了它的存在和释放，其后果是什么？（6） 流通 ETP 的功能意义。在这里，我们回顾数据时要考虑到 ETP 的功能作用。（7） 我们提出 ETP 是纤维化（或纤维化炎症）疾病的介质。根据我们对 ETP 的了解，我们必须将其视为治疗纤维化（或纤维化炎症）疾病的靶点。哪些患者群体对 ETP 靶向干预的反应最明显？我们如何找到能从干预中获益最多的人群？我们旨在对整个 ETP 领域进行广泛的概述，评估未来的研究工作需要在哪里，以挖掘 ETP 作为不同疾病的标志物和靶点的巨大潜力。