Department of Aquaculture, National Penghu University of Science and Technology, Magong, Taiwan.
Sorbonne Université, Faculté des Sciences, CNRS, UMR 7144, Adaptation et Diversité en Milieu Marin, Station Biologique de Roscoff, Roscoff, France.
Front Endocrinol (Lausanne). 2020 Oct 1;11:578958. doi: 10.3389/fendo.2020.578958. eCollection 2020.
Early studies recognizing the importance of the decapod eyestalk in the endocrine regulation of crustacean physiology-molting, metabolism, reproduction, osmotic balance, etc.-helped found the field of crustacean endocrinology. Characterization of putative factors in the eyestalk using distinct functional bioassays ultimately led to the discovery of a group of structurally related and functionally diverse neuropeptides, crustacean hyperglycemic hormone (CHH), molt-inhibiting hormone (MIH), gonad-inhibiting hormone (GIH) or vitellogenesis-inhibiting hormone (VIH), and mandibular organ-inhibiting hormone (MOIH). These peptides, along with the first insect member (ion transport peptide, ITP), constitute the original arthropod members of the crustacean hyperglycemic hormone (CHH) superfamily. The presence of genes encoding the CHH-superfamily peptides across representative ecdysozoan taxa has been established. The objective of this review is to, aside from providing a general framework, highlight the progress made during the past decade or so. The progress includes the widespread identification of the CHH-superfamily peptides, in particular in non-crustaceans, which has reshaped the phylogenetic profile of the superfamily. Novel functions have been attributed to some of the newly identified members, providing exceptional opportunities for understanding the structure-function relationships of these peptides. Functional studies are challenging, especially for the peptides of crustacean and insect species, where they are widely expressed in various tissues and usually pleiotropic. Progress has been made in deciphering the roles of CHH, ITP, and their alternatively spliced counterparts (CHH-L, ITP-L) in the regulation of metabolism and ionic/osmotic hemostasis under (eco)physiological, developmental, or pathological contexts, and of MIH in the stimulation of ovarian maturation, which implicates it as a regulator for coordinating growth (molt) and reproduction. In addition, experimental elucidation of the steric structure and structure-function relationships have given better understanding of the structural basis of the functional diversification and overlapping among these peptides. Finally, an important finding was the first-ever identification of the receptors for this superfamily of peptides, specifically the receptors for ITPs of the silkworm, which will surely give great impetus to the functional study of these peptides for years to come. Studies regarding recent progress are presented and synthesized, and prospective developments remarked upon.
早期研究认识到十足目虾蟹类眼柄在内分泌调节甲壳动物生理学蜕皮、代谢、生殖、渗透平衡等方面的重要性，帮助建立了甲壳动物内分泌学领域。使用不同的功能生物测定法对眼柄中假定因子的特征进行描述，最终导致了一组结构相关且功能多样的神经肽的发现，包括甲壳动物高血糖激素（CHH）、蜕皮抑制激素（MIH）、性腺抑制激素（GIH）或卵黄生成抑制激素（VIH）和下颚器官抑制激素（MOIH）。这些肽与第一个昆虫成员（离子转运肽，ITP）一起构成了甲壳动物高血糖激素（CHH）超家族的原始节肢动物成员。已经确定了代表蜕皮动物的基因编码 CHH 超家族肽。本文的目的除了提供一个总体框架外，还强调了过去十年左右的进展。这些进展包括 CHH 超家族肽的广泛鉴定，特别是在非甲壳类动物中的鉴定，这重塑了超家族的系统发育特征。一些新鉴定的成员被赋予了新的功能，为这些肽的结构-功能关系提供了极好的理解机会。功能研究具有挑战性，特别是对于甲壳类和昆虫物种的肽，它们在各种组织中广泛表达且通常具有多功能性。在（生态）生理、发育或病理环境下，CHH、ITP 及其选择性剪接对应物（CHH-L、ITP-L）在调节代谢和离子/渗透稳态方面的作用，以及 MIH 在刺激卵巢成熟方面的作用，已经取得了进展，这表明它是协调生长（蜕皮）和生殖的调节剂。此外，对 CHH 和 MIH 结构-功能关系的实验阐明，使我们更好地理解了这些肽的功能多样化和重叠的结构基础。最后，一个重要的发现是首次鉴定了这些肽的受体，特别是家蚕 ITP 受体，这无疑将在未来几年为这些肽的功能研究提供巨大动力。本文介绍和综合了关于最新进展的研究，并对未来的发展进行了评述。
