尽管短链脂肪酸通过游离脂肪酸受体2/3诱导胰高血糖素样肽-1分泌,但葡聚糖硫酸钠诱导的结肠炎严重程度与短链脂肪酸-游离脂肪酸受体2/3-胰高血糖素样肽-1途径无关。

The Severity of DSS-Induced Colitis Is Independent of the SCFA-FFAR2/3-GLP-1 Pathway Despite SCFAs Inducing GLP-1 Secretion via FFAR2/3.

作者信息

Hunt Jenna Elizabeth, Christiansen Charlotte Bayer, Yassin Mohammad, Hartmann Bolette, Offermanns Stefan, Dragsted Lars Ove, Holst Jens Juul, Kissow Hannelouise

机构信息

Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.

Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.

出版信息

Metabolites. 2024 Jul 20;14(7):395. doi: 10.3390/metabo14070395.

Abstract

Short-chain fatty acids (SCFAs) are the major microbial metabolites produced from the fermentation of dietary fiber in the gut. They are recognised as secretagogues of the glucagon-like peptides, GLP-1 and GLP-2, likely mediated by the activation of free fatty acid receptors 2 and 3 (FFAR2 and 3) expressed on enteroendocrine L-cells. Fiber-deficient diets are associated with decreased intestinal function and decreased colonic GLP-1 and GLP-2 content. Here, we speculated that the lowered colonic GLP-1 observed following a fiber-free diet was a consequence of decreased SCFA production and a subsequent decrease in FFAR2/3 activation. Furthermore, we explored the consequences of a fiber-free diet followed by intestinal injury, and we mechanistically explored the SCFA-FFAR2/3-GLP-1 pathway to explain the increased severity. Colonic luminal content from mice fed either a fiber-free or chow diet were analysed for SCFA content by LC-MS. FFAR2/3 receptor contributions to SCFA-mediated colonic GLP-1 secretion were assessed in isolated perfused preparations of the colon from FFAR2/3 double knockout (KO) and wild-type (WT) mice. Colitis was induced by the delivery of 3% dextran sulfate sodium (DSS) for 4 days in the drinking water of mice exposed to a fiber-free diet for 21 days. Colitis was induced by the delivery of 3% DSS for 7 days in FFAR2/3 KO mice. The removal of dietary fiber significantly decreased SCFA concentrations in the luminal contents of fiber-free fed mice compared to chow-fed mice. In the perfused colon, luminal SCFAs significantly increased colonic GLP-1 secretion in WT mice but not in FFAR2/3 KO mice. In the DSS-induced colitis model, the removal of dietary fiber increased the severity and prevented the recovery from intestinal injury. Additionally, colitis severity was similar in FFAR2/3 KO and WT mice after DSS application. In conclusion, the results confirm that the removal of dietary fiber is sufficient to decrease the colonic concentrations of SCFAs. Additionally, we show that a fiber-free diet predisposes the colon to increased intestinal injury, but this effect is independent of FFAR2 and FFAR3 signalling; therefore, it is unlikely that a fiber-free diet induces a decrease in luminal SCFAs and sensitivity to intestinal disease involves the SCFA-FFAR2/3-GLP-1 pathway.

摘要

短链脂肪酸(SCFAs)是肠道中膳食纤维发酵产生的主要微生物代谢产物。它们被认为是胰高血糖素样肽GLP - 1和GLP - 2的促分泌剂,可能是通过激活肠内分泌L细胞上表达的游离脂肪酸受体2和3(FFAR2和FFAR3)介导的。缺乏纤维的饮食与肠道功能下降以及结肠GLP - 1和GLP - 2含量降低有关。在此,我们推测无纤维饮食后观察到的结肠GLP - 1降低是SCFA产生减少以及随后FFAR2/3激活减少的结果。此外,我们探讨了无纤维饮食后肠道损伤的后果,并从机制上探究了SCFA - FFAR2/3 - GLP - 1途径以解释严重程度增加的原因。通过液相色谱 - 质谱法分析了喂食无纤维饮食或普通饮食小鼠的结肠腔内容物中的SCFA含量。在FFAR2/3双敲除(KO)和野生型(WT)小鼠的离体灌注结肠制剂中评估了FFAR2/3受体对SCFA介导的结肠GLP - 1分泌的作用。在暴露于无纤维饮食21天的小鼠饮用水中给予3%硫酸葡聚糖钠(DSS)4天诱导结肠炎。在FFAR2/3 KO小鼠中给予3% DSS 7天诱导结肠炎。与喂食普通饮食的小鼠相比,去除膳食纤维显著降低了喂食无纤维饮食小鼠腔内容物中的SCFA浓度。在灌注结肠中,腔内SCFAs显著增加了WT小鼠的结肠GLP - 1分泌,但在FFAR2/3 KO小鼠中未增加。在DSS诱导的结肠炎模型中,去除膳食纤维增加了严重程度并阻碍了肠道损伤的恢复。此外,应用DSS后,FFAR2/3 KO小鼠和WT小鼠的结肠炎严重程度相似。总之,结果证实去除膳食纤维足以降低结肠中SCFAs的浓度。此外,我们表明无纤维饮食使结肠更容易受到肠道损伤增加的影响,但这种作用独立于FFAR2和FFAR3信号传导;因此,无纤维饮食不太可能通过SCFA - FFAR2/3 - GLP - 1途径诱导腔内SCFAs减少和对肠道疾病的易感性增加。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/bea8/11278623/129f153decc7/metabolites-14-00395-g001.jpg

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