Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China.
Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
Mediators Inflamm. 2024 May 2;2024:7524314. doi: 10.1155/2024/7524314. eCollection 2024.
Microfold cells (M cells) are specific intestinal epithelial cells for monitoring and transcytosis of antigens, microorganisms, and pathogens in the intestine. However, the mechanism for M-cell development remained elusive.
Real-time polymerase chain reaction, immunofluorescence, and western blotting were performed to analyze the effect of sorbitol-regulated M-cell differentiation and , and luciferase and chromatin Immunoprecipitation were used to reveal the mechanism through which sorbitol-modulated M-cell differentiation.
Herein, in comparison to the mannitol group (control group), we found that intestinal M-cell development was inhibited in response to sorbitol treatment as evidenced by impaired enteroids accompanying with decreased early differentiation marker Annexin 5, Marcksl1, Spib, sox8, and mature M-cell marker glycoprotein 2 expression, which was attributed to downregulation of receptor activator of nuclear factor kappa-В ligand (RANKL) expression and . Mechanically, in the M-cell model, sorbitol stimulation caused a significant upregulation of phosphodiesterase 4 (PDE4) phosphorylation, leading to decreased protein kinase A (PKA)/cAMP-response element binding protein (CREB) activation, which further resulted in CREB retention in cytosolic and attenuated CREB binds to RANKL promoter to inhibit RANKL expression. Interestingly, endogenous PKA interacted with CREB, and this interaction was destroyed by sorbitol stimulation. Most importantly, inhibition of PDE4 by dipyridamole could rescue the inhibitory effect of sorbitol on intestinal enteroids and M-cell differentiation and mature and .
These findings suggested that sorbitol suppressed intestinal enteroids and M-cell differentiation and matured through PDE4-mediated RANKL expression; targeting to inhibit PDE4 was sufficient to induce M-cell development.
微褶皱细胞（M 细胞）是一种特殊的肠道上皮细胞，可监测和转导肠道中的抗原、微生物和病原体。然而，M 细胞的发育机制仍不清楚。
实时聚合酶链反应、免疫荧光和 Western blot 用于分析山梨醇调节 M 细胞分化的效果，以及 Luciferase 和染色质免疫沉淀用于揭示山梨醇调节 M 细胞分化的机制。
与甘露醇组（对照组）相比，我们发现山梨醇处理抑制了肠道 M 细胞的发育，表现在类器官发育受损，早期分化标志物 Annexin 5、Marcksl1、Spib、sox8 和成熟 M 细胞标志物糖蛋白 2 的表达减少，这归因于核因子 kappa-B 配体（RANKL）表达的下调。在 M 细胞模型中，山梨醇刺激导致磷酸二酯酶 4（PDE4）磷酸化显著上调，导致蛋白激酶 A（PKA）/环磷酸腺苷反应元件结合蛋白（CREB）激活减少，进而导致 CREB 保留在细胞质中，并减弱 CREB 与 RANKL 启动子结合，抑制 RANKL 表达。有趣的是，内源性 PKA 与 CREB 相互作用，这种相互作用被山梨醇刺激破坏。最重要的是，通过双嘧达莫抑制 PDE4 可以挽救山梨醇对肠道类器官和 M 细胞分化和成熟的抑制作用。
这些发现表明，山梨醇通过 PDE4 介导的 RANKL 表达抑制肠道类器官和 M 细胞的分化和成熟；靶向抑制 PDE4 足以诱导 M 细胞的发育。
