Research progress on the relationship between Paneth cellssusceptibility genes,intestinal microecology and inflammatory bowel disease

Inflammatory bowel disease(IBD)is a disorder of the immune system and intestinal microecosystem caused by environmental factors in genetically susceptible people.Paneth cells(PCs)play a central role in IBD pathogenesis,especially in Crohn's disease development,and their morphology,number and function are regulated by susceptibility genes.In the intestine,PCs participate in the formation of the stem cell microenvironment by secreting antibacterial particles and play a role in helping maintain the intestinal microecology and intestinal mucosal homeostasis.Moreover,PC proliferation and maturation depend on symbiotic flora in the intestine.This paper describes the interactions among susceptibility genes,PCs and intestinal microecology and their effects on IBD occurrence and development.

Paneth cells in farm animals:current status and future direction

A healthy intestine plays an important role in the growth and development of farm animals.In small intestine,Paneth cells are well known for their regulation of intestinal microbiota and intestinal stem cells(ISCs).Although there has been a lot of studies and reviews on human and murine Paneth cells under intestinal homeostasis or disorders,little is known about Paneth cells in farm animals.Most farm animals possess Paneth cells in their small intestine,as identified by various staining methods,and Paneth cells of various livestock species exhibit noticeable differences in cell shape,granule number,and intestinal distribution.Paneth cells in farm animals and their antimicrobial peptides(AMPs)are susceptible to multiple factors such as dietary nutrients and intestinal infection.Thus,the comprehensive understanding of Paneth cells in different livestock species will contribute to the improvement of intestinal health.This review first summarizes the current status of Paneth cells in pig,cattle,sheep,horse,chicken and rabbit,and points out future directions for the investigation of Paneth cells in the reviewed animals.

Paneth cells in intestinal physiology and pathophysiology

Small intestinal mucosa is characterised by villus forming connective tissues with highly specialised surface lining epithelial cells essentially contributing to the establishment of the intestinal border.In order to perform these diverse functions,spatially distinct compartments of epithelial differentiation are found along the crypt-villus axis,including Paneth cells as a highly specialised cell type.Paneth cells locate in crypts and assist undifferentiated columnar cells,called crypt base columnar cells,and rapidly amplifying cells in the regeneration of absorptive and secretory cell types.There is some evidence that Paneth cells are involved in the configuration and function of the stem cell zone as well as intestinal morphogenesis and crypt fission.However,the flow of Paneth cells to crypt bottoms requires strong Wnt signalling guided by EphB3 and partially antagonised by Notch.In addition,mature Paneth cells are essential for the production and secretion of antimicrobial peptides including α-defensins/cryptdins.These antimicrobials are physiologically involved in shaping the composition of the microbiome.The autophagy related 16-like 1(ATG16L1) is a genetic risk factor and is involved in the exocytosis pathway of Paneth cells as well as a linker molecule to PPAR signalling and lipid metabolism.There is evidence that injuries of Paneth cells are involved in the etiopathogenesis of different intestinal diseases.The review provides an overview of the key points of Paneth cell activities in intestinal physiology and pathophysiology.

Paneth cell与肠道健康

潘氏细胞(paneth cell,PC)是由肠道干细胞(intestinal stem cells,ISC)分化而来并定居于小肠隐窝底部的分泌性细胞,是肠道健康的重要“守卫者”.PC可分泌多种抗菌肽和细胞因子以调节肠道稳态与免疫反应,还可以合成分泌多种生长因子维持ISC的生态位,调控ISC增殖分化,甚至可作为静态干细胞库,在肠组织受损时获得干细胞样特性促进组织再生,从而有助于修复受损的肠组织.此外,PC与一些影响肠道健康的疾病密切相关,如炎症性肠病(inflammatory bowel disease,IBD)和结直肠癌(colorectal cancer,CRC),对于PC的研究或许可以为这些疾病的治疗提供思路.由此可见,PC功能的正常在维持肠道生理作用中值得高度重视.

Gut commensal bacteria, Paneth cells and their relations to radiation enteropathy

In steady state, the intestinal epithelium forms an important part of the gut barrier to defend against luminal bacterial attack. However, the intestinal epithelium is compromised by ionizing irradiation due to its inherent selfrenewing capacity. In this process, small intestinal bacterial overgrowth is a critical event that reciprocally alters the immune milieu. In other words, intestinal bacterial dysbiosis induces inflammation in response to intestinal injuries, thus influencing the repair process of irradiated lesions. In fact, it is accepted that commensal bacteria can generally enhance the host radiation sensitivity. To address the determination of radiation sensitivity, we hypothesize that Paneth cells press a critical "button" because these cells are central to intestinal health and disease by using their peptides, which are responsible for controlling stem cell development in the small intestine and luminal bacterial diversity. Herein,the most important question is whether Paneth cells alter their secretion profiles in the situation of ionizing irradiation. On this basis, the tolerance of Paneth cells to ionizing radiation and related mechanisms by which radiation affects Paneth cell survival and death will be discussed in this review. We hope that the relevant results will be helpful in developing new approaches against radiation enteropathy.

Paneth cells: the hub for sensing and regulating intestinal flora

The complex interplay between symbiotic bacteria and host immunity plays a key role in shaping intestinal homeostasis and maintaining host health. Paneth cells, as one of the major producers of antimicrobial peptides in the intestine under steady-state conditions, play a vital role in regulating intestinal flora. Many studies on inflammatory bowel disease(IBD)-associated genes have put Paneth cells at the center of IBD pathogenesis. In this perspective, we focus on mechanistic studies of different cellular processes in Paneth cells that are regulated by various IBD-associated susceptibility genes, and we discuss the hypothesis that Paneth cells function as the central hub for sensing and regulating intestinal flora in the maintenance of intestinal homeostasis.

肠上皮细胞Axin1缺失可调节肠道微生态预防结肠炎

Intestinal homeostasis is maintained by specialized host cells and the gut microbiota.Wnt/β-catenin signaling is essential for gastrointestinal development and homeostasis,and its dysregulation has been implicated in inflammation and colorectal cancer.Axin1 negatively regulates activated Wnt/β-catenin signaling,but little is known regarding its role in regulating host–microbial interactions in health and disease.Here,we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation.Axin1 expression was analyzed in human inflammatory bowel disease datasets.To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis,we generated new mouse models with Axin1 conditional knockout in intestinal epithelial cell(IEC;Axin1^(ΔIEC))and Paneth cell(PC;Axin1^(ΔPC))to compare with control(Axin1^(LoxP);LoxP:locus of X-over,P1)mice.We found increased Axin1 expression in the colonic epithelium of human inflammatory bowel disease(IBD).Axin1^(ΔIEC) mice exhibited altered goblet cell spatial distribution,PC morphology,reduced lysozyme expression,and enriched Akkermansia muciniphila(A.muciniphila).The absence of intestinal epithelial and PC Axin1 decreased susceptibility to dextran sulfate sodium(DSS)-induced colitis in vivo.Axin1^(ΔIEC) and Axin1^(ΔPC)mice became more susceptible to DSS-colitis after cohousing with control mice.Treatment with A.muciniphila reduced DSS-colitis severity.Antibiotic treatment did not change the IEC proliferation in the Axin1Loxp mice.However,the intestinal proliferative cells in Axin1^(ΔIEC)mice with antibiotic treatment were reduced compared with those in Axin1^(ΔIEC) mice without treatment.These data suggest non-colitogenic effects driven by the gut microbiome.In conclusion,we found that the loss of intestinal Axin1 protects against colitis,likely driven by epithelial Axin1 and Axin1-associated A.muciniphila.Our study demonstrates a novel role of Axin1 in mediating intestinal homeostasis and the microbiota.Further mechanistic studies using specific Axin1 mutations elucidating how Axin1 modulates the microbiome and host inflammatory response will provide new therapeutic strategies for human IBD.

基于线粒体功能及能量代谢探讨潘氏细胞与肠道干细胞的交互作用及中医药作用的可能靶点研究进展

肠道干细胞与潘氏细胞相互作用,共同维护肠道稳态及功能,肠道干细胞及潘氏细胞交互过程受到线粒体相关功能及能量转化的调控。中医药治疗肠道疾病的独特优势也体现在其对于线粒体及能量代谢的作用方面。本文探讨线粒体功能及能量代谢对肠道干细胞、潘氏细胞交互的影响,并探索中医药治疗肠道疾病中与线粒体相关的可能靶点,总结中医药对线粒体及能量代谢的调节作用,进而恢复肠道稳态,缓解疾病。以期为基于线粒体研究肠道干细胞、潘氏细胞的中医药治疗相关研究提供一定的参考及理论依据。

From intestinal stem cells to inflammatory bowel diseases

The pathogenesis of both entities of inflammatory bowel disease (IBD), namely Crohn's disease (CD) and ulcerative colitis (UC), is still complex and under investigation. The importance of the microbial flora in developing IBD is beyond debate. In the last few years, the focus has changed from adaptive towards innate immunity. Crohn's ileitis is associated with a deficiency of the antimicrobial shield, as shown by a reduced expression and secretion of the Paneth cell defensin HD5 and HD6, which is related to a Paneth cell differentiation defect mediated by a diminished expression of the Wnt transcription factor TCF4. In UC, the protective mucus layer, acting as a physical and chemical barrier between the gut epithelium and the luminal microbes, is thin- ner and in part denuded as compared to controls. This could be caused by a missing induction of the goblet cell differentiation factors Hath1 and KLF4 leading to immature goblet cells. This defective Paneth and goblet cell differentiation in Crohn's ileitis and UC may enablethe luminal microbes to invade the mucosa and trigger the inflammation. The exact molecular mechanisms behind ileal CD and also UC must be further clarified, but these observations could give rise to new therapeutic strategies based on a stimulation of the protective innate immune system.

克霉唑对Paneth细胞防御素分泌的抑制作用

目的 观察克霉唑 (clotrimazole ,CLT)对Paneth细胞防御素的抑制作用。方法 采用RT PCR技术和Northern印迹技术观察克霉唑对Paneth细胞防御素基因表达的影响 ,采用dot blot和ELISA观察Paneth细胞防御素分泌的影响。结果 CLT对Paneth细胞防御素的基因表达没有影响 ,而 12 5、2 5 0、5 0 0nmol·L-1的CLT对α 防御素的分泌有明显抑制 (P <0 0 1) ,并存在剂量依赖关系。结论 CLT能抑制防御素的分泌 。

大黄附子汤灌胃对小鼠重症急性胰腺炎的治疗作用及其机制

目的通过建立小鼠重症急性胰腺炎(SAP)模型,观察大黄附子汤对小鼠SAP的治疗作用并分析其机制。方法SPF小鼠按随机数字表法分为对照组、模型组、大黄附子汤组,每组8只。除对照组外,各组均通过腹腔注射左旋精氨酸建立大鼠SAP模型。大黄附子汤组在建模后6、12 h给予1.5 mL大黄附子汤灌胃,对照组、模型组在同时点给予1.5 mL生理盐水灌胃。末次灌胃结束后麻醉小鼠,采集眼球血,ELISA法检测SAP标志物淀粉酶(AMS)、脂肪酶(LPS)及炎症反应指标肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)。采集小鼠胰腺、肺、结肠组织样本,HE染色进行病理观察,对各组织进行病理学评分。采用免疫组织化学检测及Western blotting检测小肠组织α防御素6(DEFA6)、葡萄糖调节蛋白78(GRP78)蛋白,免疫荧光染色检测小肠组织溶菌酶。结果血清AMS、LPS、TNF-α、IL-6水平模型组>大黄附子汤组>对照组(P均<0.05)。对照组胰腺、肺、结肠组织结构完整,未见炎症细胞浸润;模型组胰腺、肺、结肠组织结构被破坏,可见红细胞渗出及炎症细胞浸润;大黄附子汤组各组织病理均较模型组有所改善;胰腺、肺、结肠组织病理学评分模型组>大黄附子汤组>对照组(P均<0.05)。小肠组织DEFA6蛋白表达模型组<大黄附子汤组<对照组,GRP78蛋白表达模型组>大黄附子汤组>对照组,溶菌酶相对荧光强度模型组<大黄附子汤组<对照组(P均<0.05)。结论大黄附子汤灌胃对小鼠SAP具有一定的治疗作用,其机制可能与抑制潘氏细胞内质网应激、增加抗菌分子DEFA6分泌从而改善肠屏障功能有关。

Paneth细胞与炎症性肠病

Paneth细胞是一种分布于肠腺底部的肠黏膜分化上皮细胞,可向腺体分泌生长因子和抗微生物肽如溶菌酶和防御素。随着对炎症性肠病（IBD）发病机制研究的不断深入,已发现Paneth细胞及其分泌的抗微生物分子参与了肠道黏膜屏障的破坏,可致自身免疫失衡,启动肠道炎症反应,从而引起肠道黏膜功能的改变,在IBD的触发和复发中起一定作用。Paneth细胞在IBD中是参与免疫防御还是促进免疫损伤,目前仍在研究讨论中。

WJSC 6^(th) Anniversary Special Issues(2):Mesenchymal stem cells Intestinal stem cells and celiac disease

Stem cells(SCs)are the key to tissue genesis and regeneration.Given their central role in homeostasis,dysfunctions of the SC compartment play a pivotal role in the development of cancers,degenerative disorders,chronic inflammatory pathologies and organ failure.The gastrointestinal tract is constantly exposed to harsh mechanical and chemical conditions and most of the epithelial cells are replaced every 3 to 5 d.According to the so-called Unitarian hypothesis,this renewal is driven by a common intestinal stem cell(ISC)residing within the crypt base at the origin of the crypt-to-villus hierarchical migratory pattern.Celiac disease(CD)can be defined as a chronic immune-mediated disease that is triggered and maintained by dietary proteins(gluten)in genetically predisposed individuals.Many advances have been achieved over the last years in understanding of the pathogenic interactions among genetic,immunological and environmental factors in CD,with a particular emphasis on intestinal barrier and gut microbiota.Conversely,little is known about ISC modulation and deregulation in active celiac disease and upon a gluten-free diet.Nonetheless,bone marrow-derived SC transplantation has become an option for celiac patients with complicated or refractory disease.This manuscript summarizes the"state of the art"regarding CD and ISCs,their niche and potential role in the development and treatment of the disease.

Crohn’s disease: Why the ileum?

Crohn’s disease(CD)is an inflammatory bowel disease characterized by immunemediated flares affecting any region of the intestine alternating with remission periods.In CD,the ileum is frequently affected and about one third of patients presents with a pure ileal type.Moreover,the ileal type of CD presents epidemiological specificities like a younger age at onset and often a strong link with smoking and genetic susceptibility genes.Most of these genes are associated with Paneth cell dysfunction,a cell type found in the intestinal crypts of the ileum.Besides,a Western-type diet is associated in epidemiological studies with CD onset and increasing evidence shows that diet can modulate the composition of bile acids and gut microbiota,which in turn modulates the susceptibility of the ileum to inflammation.Thus,the interplay between environmental factors and the histological and anatomical features of the ileum is thought to explain the specific transcriptome profile observed in CD ileitis.Indeed,both immune response and cellular healing processes harbour differences between ileal and non-ileal CD.Taken together,these findings advocate for a dedicated therapeutic approach to managing ileal CD.Currently,interventional pharmacological studies have failed to clearly demonstrate distinct response profiles according to disease site.However,the high rate of stricturing disease in ileal CD requires the identification of new therapeutic targets to significantly change the natural history of this debilitating disease.

Current opinion on the regulation of small intestinal magnesium absorption

Magnesium(Mg^(2+))has an important role in numerous biological functions,and Mg^(2+)deficiency is associated with several diseases.Therefore,adequate intestinal absorption of Mg^(2+)is vital for health.The small intestine was previously thought to absorb digested Mg^(2+)exclusively through an unregulated paracellular mechanism,which is responsible for approximately 90%of total Mg^(2+)absorption.Recent studies,however,have revealed that the duodenum,jejunum,and ileum absorb Mg^(2+)through both transcellular and paracellular routes.Several regulatory factors of small intestinal Mg^(2+)uptake also have been explored,e.g.,parathyroid hormone,fibroblast growth factor-23,apical acidity,proton pump inhibitor,and pH-sensing channel and receptors.The mechanistic factors underlying proton pump inhibitor suppression of small intestinal Mg^(2+),such as magnesiotropic protein dysfunction,higher mucosal bicarbonate secretion,Paneth cell dysfunction,and intestinal inflammation,are currently being explored.The potential role of small intestinal microbiomes in Mg^(2+)absorption has also been proposed.In this article,we reviewed the current knowledge on the mechanisms and regulatory factors of small intestinal Mg^(2+)absorption.

人小肠黏膜潘氏细胞的形态学和机能

【目的】观察人各段小肠潘氏细胞的分布、形态结构特点,探讨潘氏细胞颗粒状态与小肠黏膜上皮细胞增殖之间的关系。【方法】人十二指肠、空肠、回肠及结肠黏膜上皮组织各12例,应用免疫组织化学SP法检测潘氏细胞内溶菌酶及黏膜增殖细胞核抗原(PCNA)的表达。全自动图像分析系统进行图像半定量分析。【结果】人肠道中潘氏细胞仅存在于小肠,从十二指肠、空肠到回肠,细胞数量呈递增分布,各组之间有显著性差异(P<0.05),结肠中未见有潘氏细胞。潘氏细胞的颗粒分泌状态与小肠上皮细胞PCNA增殖指数的表达呈直线正相关(r=0.776,P=0.003)。【结论】人潘氏细胞颗粒分泌与小肠黏膜细胞的增殖状态有关,PCNA指数在一定程度上可以反应肠上皮干细胞的增殖状态,潘氏细胞对维护肠黏膜屏障功能的完整性具有重要的生理学意义。

防御素在炎症性肠病中的作用机制

炎症性肠病(inflammatory bowel disease,IBD)患者或IBD动物模型肠道的防御素表达紊乱可能与IBD的发生和迁延不愈有关.防御素除了具有直接杀灭或抑制病原微生物的作用,在生物应激时还具有调节或扩大获得性免疫反应的作用.防御素表达紊乱后可能干扰了获得性免疫的启动,又扩大了肠道局部的炎症反应,加快IBD的进程.本文主要论述防御素在IBD的作用机制,并对防御素的应用前景作一展望.

潘氏细胞及其抗微生物肽与肠道黏膜免疫

潘氏细胞(Paneth cells,PCs)及其抗微生物肽(antimicrobial peptides,AMPs)与肠道微生物的生态学失衡、肠道炎症、全身感染等病理状况的发生密切相关.肠黏膜屏障与固有免疫功能的损害,常伴随着机体a-防御素等AMPs水平及其他炎症介质水平的改变.研究发现:PCs能在胆碱能兴奋剂、微生物及其抗原成分、肠内营养状态、遗传易感因素等因素的作用下,改变其本身的功能状态及效应分子的释放,诱发炎症性肠病、细菌移位、肠内细菌过度生长、自身免疫耐受损害等疾病及相关改变,对PCs的研究给临床治疗提供了新的靶点和策略.本文对近十年来人们对PCs、AMPs和肠道黏膜屏障及固有免疫之间关系的研究进展作一述评.

72h睡眠剥夺大鼠回肠溶菌酶与分泌成分的变化

目的观察睡眠剥夺大鼠回肠粘膜超微结构以及溶菌酶和分泌成分 (SC)的变化 ,探讨睡眠剥夺引起细菌移位的机制。方法 2 4只大鼠分为睡眠剥夺组、实验对照组和正常对照组 ,睡眠给予剥夺组72h睡眠剥夺处理。透射电镜观察回肠粘膜的超微结构 ,免疫组织化学方法检测溶菌酶、SC阳性肠隐窝的数目。结果睡眠剥夺组回肠粘膜固有层的组织、毛细血管和毛细淋巴管内可见大量细菌。正常对照组、实验对照组和睡眠剥夺组的溶菌酶阳性肠隐窝数分别为 86.8± 16.3、78.8± 13 .0和 5 6.6± 9.4,SC阳性肠隐窝数分别为 89.3± 14 .9、71.7± 10 .7和 5 8.4± 14 .6,睡眠剥夺组均少于正常对照组和实验对照组 (P <0 .0 1或P <0 .0 5 )。SC特异性地分布于潘氏细胞 ,与文献报道不一致。结论sIgA与溶菌酶共存于潘氏细胞的分泌颗粒 ,并协同发挥免疫屏障功能。睡眠剥夺引起的细菌移位可能与潘氏细胞的变化有关。

人防御素5研究进展

目的 探讨人防御素 5 (humandefensin 5 ,HD 5 )的分子结构、抗菌活性、基因表达等特点 ,展望HD 5作为抗肠源性感染新药的开发前景。方法 采用文献回顾的方法对有关HD 5研究资料进行综合比较和综述。结果 HD 5是一种不含糖链的碱性阳离子多肽 ,相对分子质量为 ( 3～ 5 )× 10 3 ,成熟肽由 32个氨基酸残基组成 ,富含精氨酸、半胱氨酸 ;分子内含有 3对由半胱氨酸形成的二硫键 ,并以此行使其对革兰氏阳性菌、革兰氏阴性菌、真菌、螺旋体、原生动物、有包膜病毒等的抗菌功能。HD 5的编码基因DEFA5位于第 8条染色体P2 1 pter区 ,全长4 4 9bp。其中 1～ 4 0为 5′端非翻译区 ,4 1～ 97为信号肽序列 ,98～ 2 2 6编码HD 5前片段 ,2 2 7～ 32 2为HD 5成熟肽编码序列 ,PolyA序列位于 4 33～ 4 38。 结论 HD 5是一种广谱、高效、不产生耐药性的内源性抗微生物小分子肽 ,如能解决其大量生产的难点 。