Purpose

Commensal microbiome secretes various metabolites that can exert important effects on the host immunity and inflammation and can alter cellular functions. However, little is known regarding the effect of microbiome on corneal immunity and genetic expression. The purpose of this study is to describe the effect of diet-induced gut dysbiosis on corneal immunity and corneal gene expression after wounding.

Methods

This study is approved by the Animal Care and Use of the University of Illinois. Six-week-old female C57BL6 mice were fed on a normal chow diet (ND), isocaloric low-fat control diet (LFD), or a 21% milk high-fat diet (HFD) for six weeks. 2 mm corneal epithelial debridement was performed (n = 10). Fecal samples from mice were used for microbial diversity analysis (n > 3). Immunofluorescence staining of corneal wholemount tissue post-debridement was used to visualize immune cell distribution. RNA Seq was performed on tissue samples from corneas following debridement.

Results

Mice fed differing diets had significant alterations in gut microbial diversities. After corneal debridement, HFD mice experienced delayed wound healing in comparison to LFD mice and ND mice groups. However, fecal transplantation led to normalization of wound closure rates. Increased γδTCR staining was observed in the LFD group, and decreased LY6G was observed in HFD group (p < 0.05). Gene Ontology terms of differentially expressed genes included response to external stimulus, cell proliferation, migration, adhesion, defense response and leukocyte migration. Top over-represented pathways included ECM-receptor interaction, Cytokine-cytokine receptor interaction, Focal adhesion and Leukocyte trans-endothelial migration.

Conclusions

Gut microbial dysbiosis alters corneal immune cell distribution, corneal response to injury, and genes related to epithelial function and corneal immunity.

中文翻译：

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高脂肪饮食引起的肠道菌群失调改变小鼠角膜上皮损伤反应

目的

共生微生物组分泌各种代谢物，对宿主免疫和炎症产生重要影响，并可以改变细胞功能。然而，关于微生物组对角膜免疫和基因表达的影响知之甚少。本研究的目的是描述饮食引起的肠道菌群失调对受伤后角膜免疫和角膜基因表达的影响。

方法

这项研究得到了伊利诺伊大学动物护理和使用部的批准。六周大的雌性 C57BL6 小鼠以正常饲料 (ND)、等热量低脂对照饮食 (LFD) 或 21% 牛奶高脂饮食 (HFD) 喂养六周。进行 2 mm 角膜上皮清创术 (n = 10)。小鼠粪便样本用于微生物多样性分析 (n > 3)。清创后角膜整体组织的免疫荧光染色用于可视化免疫细胞分布。对清创后的角膜组织样本进行 RNA 测序。

结果

喂食不同饮食的小鼠肠道微生物多样性发生显着变化。角膜清创后，与 LFD 小鼠和 ND 小鼠组相比，HFD 小鼠的伤口愈合延迟。然而，粪便移植使伤口闭合率正常化。在 LFD 组中观察到 γδTCR 染色增加，在 HFD 组中观察到 LY6G 染色减少（p < 0.05）。差异表达基因的基因本体术语包括对外部刺激的反应、细胞增殖、迁移、粘附、防御反应和白细胞迁移。最常见的途径包括 ECM-受体相互作用、细胞因子-细胞因子受体相互作用、粘着斑和白细胞跨内皮迁移。

结论

肠道微生物失调会改变角膜免疫细胞分布、角膜对损伤的反应以及与上皮功能和角膜免疫相关的基因。