Human adenovirus 41 (HAdV-41) causes acute gastroenteritis in young children. The main characteristics of HAdV-41 infection are diarrhea and vomiting. Nevertheless, the precise mechanism of HAdV-41-induced diarrhea is unknown, as a suitable small-animal model has not been described. In this study, we used the human midgut carcinoid cell line GOT1 to investigate the effect of HAdV-41 infection and the individual HAdV-41 capsid proteins on serotonin release by enterochromaffin cells and on enteric glia cell (EGC) activation. We first determined that HAdV-41 could infect the enterochromaffin cells. Immunofluorescence staining revealed that the cells expressed HAdV-41-specific coxsackievirus and adenovirus receptor (CAR); flow cytometry analysis supported these findings. HAdV-41 infection of the enterochromaffin cells induced serotonin secretion dose dependently. In contrast, control infection with HAdV-5 did not induce serotonin secretion in the cells. Confocal microscopy studies of enterochromaffin cells infected with HAdV-41 revealed decreased serotonin immunofluorescence compared to that in uninfected cells. Incubation of the enterochromaffin cells with purified HAdV-41 short fiber knob and hexon proteins increased the serotonin levels in the harvested cell supernatant significantly. HAdV-41 infection could also activate EGCs, as shown in the significantly altered expression of glia fibrillary acidic protein (GFAP) in EGCs incubated with HAdV-41. The EGCs were also activated by serotonin alone, as shown in the significantly increased GFAP staining intensity. Likewise, EGCs were activated by the cell supernatant of HAdV-41-infected enterochromaffin cells.

IMPORTANCE The nonenveloped human adenovirus 41 causes diarrhea, vomiting, dehydration, and low-grade fever mainly in children under 2 years of age. Even though acute gastroenteritis is well described, how human adenovirus 41 causes diarrhea is unknown. In our study, we analyzed the effect of human adenovirus 41 infection on human enterochromaffin cells and found it stimulates serotonin secretion in the cells, which is involved in regulation of intestinal secretion and gut motility and can also activate enteric glia cells, which are found in close proximity to enterochromaffin cells in vivo. This disruption of gut barrier homeostasis as maintained by these cells following human adenovirus 41 infection might be a mechanism in enteric adenovirus pathogenesis in humans and could indicate a possible serotonin-dependent cross talk between human adenovirus 41, enterochromaffin cells, and enteric glia cells.

人腺病毒41（HAdV-41）引起幼儿急性肠胃炎。HAdV-41感染的主要特征是腹泻和呕吐。然而，由于尚未描述合适的小动物模型，因此尚不清楚HAdV-41诱导的腹泻的确切机制。在这项研究中，我们使用了人中肠类癌细胞系GOT1来研究HAdV-41感染和单个HAdV-41衣壳蛋白对肠嗜铬细胞释放5-羟色胺和肠神经胶质细胞（EGC）活化的影响。我们首先确定HAdV-41可以感染肠嗜铬细胞。免疫荧光染色显示细胞表达HAdV-41特异性柯萨奇病毒和腺病毒受体（CAR）。流式细胞仪分析支持了这些发现。肠嗜铬细胞的HAdV-41感染可诱导血清素分泌剂量依赖性。相反，HAdV-5的对照感染并未诱导细胞中5-羟色胺的分泌。用HAdV-41感染的肠嗜铬细胞的共聚焦显微镜研究显示，与未感染的细胞相比，血清素的免疫荧光降低。用纯化的HAdV-41短纤维瘤和六邻体蛋白对肠嗜铬细胞进行孵育，可显着提高收获的细胞上清液中的血清素水平。HAdV-41感染也可以激活EGC，如与HAdV-41孵育的EGC中的神经胶质纤维酸性蛋白（GFAP）表达明显改变所示。如图所示，GFC染色强度显着增加，单独的5-羟色胺也激活了EGC。同样地，

重要信息无包膜的人腺病毒41主要在2岁以下的儿童中引起腹泻，呕吐，脱水和低烧。即使已经很好地描述了急性肠胃炎，但人腺病毒41如何引起腹泻仍是未知的。在我们的研究中，我们分析了人腺病毒41感染对人肠嗜铬细胞的影响，发现它可以刺激细胞中血清素的分泌，这与肠道分泌和肠蠕动的调节有关，还可以激活肠上皮神经胶质细胞。体内接近肠嗜铬细胞。这些细胞在人类腺病毒41感染后维持的肠道屏障稳态平衡受到破坏，这可能是人类肠道腺病毒发病机制中的一种机制，并且可能表明人类腺病毒41，肠嗜铬细胞和肠神经胶质细胞之间可能存在血清素依赖性串扰。