Almhanna Hazem, Al-Mahmodi Aqeel Mohsin Mahdi, Kadhim Abdulrazzaq B, Kumar aArun H S
Department of Anatomy and Histology, College of Veterinary Medicine, University of Al-Qadisiyah, Al Diwaniyah, Iraq.
Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Kufa, Kufa, Iraq.
Vet World. 2024 Jun;17(6):1227-1237. doi: 10.14202/vetworld.2024.1227-1237. Epub 2024 Jun 8.
In avian and other species, mucins (MUCs) play a crucial role in the gastrointestinal tract (GIT), and constitute a large group of O-glycosylated glycoproteins, are glycoconjugate proteins. MUCs present in two forms: (1) membrane-attached on cell surfaces to repel external threats and (2) detachable, gel-forming proteins in the soluble form. In quail GIT, the specific types of MUCs that are expressed remain largely unknown. We investigated the expression of MUC1 and MUC4 MUCs in the GIT of Iraqi common quails and conducted network and structural analyses of all known MUC types across quail breeds.
Histological and gene expression analyses of MUC1 and MUC4 were conducted using fresh small intestine and large intestine samples from 10 quails. Using the STRING Database, Chimera software, and PrankWeb-ligand binding site prediction tool, network and structural analyses of all reported types of quail MUCs were conducted.
Most intestinal MUCs in quails were acidic, with few neutral MUCs detectable through Alcian blue and periodic acid-schiff stains. Acidic MUCs were more expressed in the duodenum, ileum, cecum, and colon, whereas neutral MUCs were more expressed in the jejunum. MUC1 and MUC4 messenger RNA expression was significantly higher in the jejunum and colon than in the duodenum and ileum. The analysis of the network revealed that MUC 1, 15, 16, and 24 formed homologous networks, while MUC 2, 4, 5, and 6 formed heterologous networks. Specific MUC combinations, including MUC5A-MUC6, MUC5A-MUC5B, and MUC5B-MUC6, show higher intermolecular hydrogen bond formation affinity. MUC15, MUC16, and MUC24 showed minimal interaction with other MUC types. Among the analyzed MUCs, MUC5B, and MUC6 had the highest probability for binding, while MUC2, MUC4, and MUC5A showed lower probabilities despite greater numbers of binding sites.
This study's results offer significant insights into quails' MUCs' composition, expression, network interactions, and binding sites, advancing knowledge of MUC-related processes in gastrointestinal physiology and their potential connection to gastrointestinal diseases.
在禽类和其他物种中，黏蛋白（MUCs）在胃肠道（GIT）中发挥着关键作用，它们构成了一大类O-糖基化糖蛋白，属于糖缀合物蛋白。MUCs以两种形式存在：（1）附着在细胞表面以抵御外部威胁；（2）可分离的、呈可溶性形式的凝胶形成蛋白。在鹌鹑的胃肠道中，所表达的MUCs的具体类型在很大程度上仍不清楚。我们研究了伊拉克普通鹌鹑胃肠道中MUC1和MUC4的表达情况，并对鹌鹑品种中所有已知的MUC类型进行了网络和结构分析。
使用10只鹌鹑的新鲜小肠和大肠样本进行MUC1和MUC4的组织学和基因表达分析。利用STRING数据库、Chimera软件和PrankWeb配体结合位点预测工具，对所有已报道的鹌鹑MUC类型进行网络和结构分析。
鹌鹑肠道中的大多数MUCs呈酸性，通过阿尔辛蓝和过碘酸希夫氏染色可检测到的中性MUCs很少。酸性MUCs在十二指肠、回肠、盲肠和结肠中表达较多，而中性MUCs在空肠中表达较多。MUC1和MUC4信使核糖核酸在空肠和结肠中的表达明显高于十二指肠和回肠。网络分析显示，MUC 1、15、16和24形成同源网络，而MUC 2、4、5和6形成异源网络。特定的MUC组合，包括MUC5A-MUC6、MUC5A-MUC5B和MUC5B-MUC6，显示出更高的分子间氢键形成亲和力。MUC15、MUC16和MUC24与其他MUC类型的相互作用最小。在所分析的MUCs中，MUC5B和MUC6结合的可能性最高，而MUC2、MUC4和MUC5A尽管结合位点较多，但结合可能性较低。
本研究结果为鹌鹑MUCs的组成、表达、网络相互作用和结合位点提供了重要见解，推进了对胃肠道生理学中与MUC相关过程及其与胃肠道疾病潜在联系的认识。
