Farncombe Family Digestive Health Research Institute.
Department of Pathology and Molecular Medicine.
Inflamm Bowel Dis. 2021 May 17;27(6):914-926. doi: 10.1093/ibd/izaa305.
Inflammatory bowel diseases are the most common chronic intestinal inflammatory conditions, and their incidence has shown a dramatic increase in recent decades. Limited efficacy and questionable safety profiles with existing therapies suggest the need for better targeting of therapeutic strategies. Adenosine monophosphate-activated protein kinase (AMPK) is a key regulator of cellular metabolism and has been implicated in intestinal inflammation. Macrophages execute an important role in the generation of intestinal inflammation. Impaired AMPK in macrophages has been shown to be associated with higher production of proinflammatory cytokines; however, the role of macrophage AMPK in intestinal inflammation and the mechanism by which it regulates inflammation remain to be determined. In this study, we investigated the role of AMPK with a specific focus on macrophages in the pathogenesis of intestinal inflammation.
A dextran sodium sulfate-induced colitis model was used to assess the disease activity index, histological scores, macroscopic scores, and myeloperoxidase level. Proinflammatory cytokines such as tumor necrosis factor-α, interleukin-6, and interleukin-1β were measured by enzyme-linked immunosorbent assay. Transient transfection of AMPKβ1 and LC3-II siRNA in RAW 264.7 cells was performed to elucidate the regulation of autophagy by AMPK. The expression of p-AMPK, AMPK, and autophagy markers (eg, LC3-II, p62, Beclin-1, and Atg-12) was analyzed by Western blot.
Genetic deletion of AMPKβ1 in macrophages upregulated the production of proinflammatory cytokines, aggravated the severity of dextran sodium sulfate-induced colitis in mice, which was associated with an increased nuclear translocation of nuclear factor-κB, and impaired autophagy both in vitro and in vivo. Notably, the commonly used anti-inflammatory 5-aminosalicylic acid (ie, mesalazine) and sodium salicylate ameliorated dextran sodium sulfate-induced colitis through the activation of macrophage AMPK targeting the β1 subunit.
Together, these data suggest that the development of therapeutic agents targeting AMPKβ1 may be effective in the treatment of intestinal inflammatory conditions including inflammatory bowel disease.
炎症性肠病是最常见的慢性肠道炎症性疾病，其发病率在近几十年来呈显著上升趋势。现有治疗方法的疗效有限且安全性存在疑问，这表明需要更好地针对治疗策略。腺苷单磷酸激活蛋白激酶（AMPK）是细胞代谢的关键调节剂，并且与肠道炎症有关。巨噬细胞在产生肠道炎症方面发挥着重要作用。已经表明，巨噬细胞中 AMPK 的功能障碍与促炎细胞因子的产生增加有关；然而，巨噬细胞 AMPK 在肠道炎症中的作用及其调节炎症的机制仍有待确定。在这项研究中，我们研究了 AMPK 的作用，特别是聚焦于巨噬细胞在肠道炎症发病机制中的作用。
使用葡聚糖硫酸钠诱导的结肠炎模型来评估疾病活动指数、组织学评分、宏观评分和髓过氧化物酶水平。通过酶联免疫吸附试验测量促炎细胞因子，如肿瘤坏死因子-α、白细胞介素-6 和白细胞介素-1β。通过瞬时转染 RAW 264.7 细胞中的 AMPKβ1 和 LC3-II siRNA，阐明 AMPK 对自噬的调节作用。通过 Western blot 分析 p-AMPK、AMPK 和自噬标志物（例如，LC3-II、p62、Beclin-1 和 Atg-12）的表达。
巨噬细胞中 AMPKβ1 的基因缺失增加了促炎细胞因子的产生，加剧了葡聚糖硫酸钠诱导的结肠炎小鼠的严重程度，这与核因子-κB 的核转位增加以及自噬受损有关，无论是在体外还是在体内。值得注意的是，常用的抗炎药 5-氨基水杨酸（即美沙拉嗪）和水杨酸钠通过靶向β1 亚基激活巨噬细胞 AMPK 来改善葡聚糖硫酸钠诱导的结肠炎。
这些数据表明，针对 AMPKβ1 的治疗剂的开发可能对包括炎症性肠病在内的肠道炎症性疾病的治疗有效。
