溃疡性结肠炎(UC)是一种炎症性肠病,以复发和缓解的方式表现为大肠的刺激或肿胀和疮。在葡聚糖硫酸钠(DSS)诱导的雌性小鼠UC模型中,我们发现环磷酸鸟苷(cGMP)的水平降低,而磷酸二酯酶9A(PDE9A)的表达在所有磷酸二酯酶(PDEs)中最高。由于PDE9对cGMP具有最高的亲和力,我们评估了选择性PDE9抑制剂PF-04447943(PF)作为UC治疗的潜在候选药物.PF在认知功能和镰状细胞疾病中得到了广泛的研究,但在炎症性肠病(IBD)模型中没有。因此,我们使用单独用3%DSS处理或与PF或柳氮磺吡啶(SASP)共同处理的雌性C57BL/6小鼠来研究体重,结肠长度,组织病理学,并测量超氧化物歧化酶(SOD),丙二醛(MDA),和cGMP水平,以及细胞因子,如肿瘤坏死因子-α(TNF-α),白细胞介素-6(IL-6),白细胞介素-17(IL-17),白细胞介素-12/23(IL-12/23),白细胞介素-10(IL-10),和途径包括核因子κB(NF-κB),信号转导和转录激活因子3(STAT3),和炎症体激活。此外,在脾脏中评估树突状细胞(DC)和调节性T细胞(Treg细胞)的数量,淋巴结,和结肠使用流式细胞术。DSS减少了杯状细胞的数量,减少结肠长度和体重,所有这些都通过PF治疗减弱。它还抑制了炎症细胞因子的升高水平和抗炎细胞因子的升高水平,IL-10.PF治疗还通过抑制氧化应激减少DSS诱导的炎症,NF-κB,STAT3和炎性体激活,通过细胞外信号调节激酶(ERK)磷酸化上调核因子红系2相关因子2(Nrf-2)及其下游蛋白。重要的是,PF逆转Treg/T辅助17细胞(Th17)细胞比例失衡,可能通过调节树突状细胞和Treg的发育过程。总之,本研究显示PDE9A抑制剂通过抑制氧化应激和炎症反应以及逆转Treg/Th17细胞失衡对溃疡性结肠炎的保护作用.
Ulcerative colitis (UC) is a form of inflammatory bowel disease, which manifests as irritation or swelling and sores in the large intestine in a relapsing and remitting manner. In a dextran sulfate sodium sulfate (DSS)-induced UC model in female mice, we found that the levels of cyclic guanosine monophosphate (cGMP) are reduced, while the expression of phosphodiesterase 9A (PDE9A) is highest among all phosphodiesterase (PDEs). Since PDE9 has the highest affinity toward cGMP, we evaluated the selective PDE9 inhibitor PF-04447943 (PF) as a potential candidate for UC treatment. PF has been extensively studies in cognitive function and in sickle cell disease, but not in models for inflammatory bowel disease (IBD). Therefore, we used female C57BL/6 mice treated with 3% DSS alone or co-treated with PF or sulfasalazine (SASP) to study the body weight, colon length, histopathology, and measure superoxide dismutase (SOD), malondialdehyde (MDA), and cGMP level, as well as cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17 (IL-17), interleukin-12/23 (IL-12/23), interleukin-10 (IL-10), and pathways including nuclear factor kappa B (NF-κB), signal transducer and activator of transcription 3 (STAT3), and inflammasome activation. In addition, the number of dendritic cells (DC) and regulatory T cells (Treg cell) was assessed in the spleen, lymph node, and colon using flow cytometry. DSS reduced the number of goblet cells, decreased colon lengths and body weights, all of them were attenuated by PF treatment. It also suppressed the elevated level of inflammatory cytokines and increased level the anti-inflammatory cytokine, IL-10. PF treatment also reduced the DSS-induced inflammation by suppressing oxidative stress, NF-κB, STAT3, and inflammasome activation, by upregulating nuclear factor erythroid 2-related factor 2 (Nrf-2) and its downstream proteins via extracellular signal-regulated kinase (ERK) phosphorylation. Importantly, PF reversed imbalance in Treg/T helper 17 cells (Th17) cells ratio, possibly by regulating dendritic cells and Treg developmental process. In summary, this study shows the protective effect of a PDE9A inhibitor in ulcerative colitis by suppressing oxidative stress and inflammation as well as reversing the Treg/Th17 cells imbalance.