The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Department of Oral Radiology, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
J Oral Pathol Med. 2019 Jan;48(1):87-95. doi: 10.1111/jop.12793. Epub 2018 Nov 14.
Sialadenitis is a nonneoplastic disease that causes salivary dysfunction. Autophagy may be involved in helping protect salivary function when the salivary gland is impaired; this process is primarily activated by sensors of innate immunity, such as Toll-like receptors and nucleotide-binding oligomerization domain (NOD)-like receptors. The role of these pattern recognition receptors (PRRs) in the regulation of salivary gland tissue defense and homeostasis has been underappreciated. This study hypothesized that NOD2 and TLR4 have a synergistic effect on the activation of autophagy in human submandibular gland (HSG) inflammation.
Submandibular gland inflammation was modeled by treating HSG cell lines in vitro with muramyl dipeptide (MDP) and lipopolysaccharide (LPS) for 24 hours. The mRNA and protein expression of NOD2, TLR4 and autophagy-related proteins (ATG5, LC3, Beclin1) were evaluated by real-time PCR and Western blot. Immunohistochemistry and double immunofluorescence were used to analyze the presence, distribution and colocalization of the aforementioned indicators in HSG tissues.
The mRNA and protein expression of autophagy-related proteins were significantly increased in HSG cells costimulated with LPS and MDP for 24 hours. NOD2, TLR4 and the autophagy-related proteins were also highly expressed in residual acini and dilated ducts of chronic submandibular sialadenitis tissues. In addition, PRRs and autophagy markers were obviously colocalized in chronic submandibular sialadenitis tissues and HSG cells.
TLR4 and NOD2 have unique expression sites in salivary glands, and they may synergistically activate autophagy in salivary glands under conditions of inflammation.
唾液腺炎是一种导致唾液功能障碍的非肿瘤性疾病。自噬可能有助于保护唾液腺受损时的唾液功能；这个过程主要是由先天免疫传感器激活的，如 Toll 样受体和核苷酸结合寡聚化结构域 (NOD)-样受体。这些模式识别受体 (PRR) 在调节唾液腺组织防御和动态平衡中的作用尚未得到充分认识。本研究假设 NOD2 和 TLR4 在人下颌下腺 (HSG) 炎症中对自噬的激活具有协同作用。
通过在体外用 muramyl dipeptide (MDP) 和脂多糖 (LPS) 处理 HSG 细胞系 24 小时来模拟下颌下腺炎症。通过实时 PCR 和 Western blot 评估 NOD2、TLR4 和自噬相关蛋白 (ATG5、LC3、Beclin1) 的 mRNA 和蛋白表达。免疫组织化学和双重免疫荧光用于分析 HSG 组织中上述标志物的存在、分布和共定位。
LPS 和 MDP 共同刺激 HSG 细胞 24 小时后，自噬相关蛋白的 mRNA 和蛋白表达明显增加。NOD2、TLR4 和自噬相关蛋白在下颌下腺慢性唾液腺炎组织的残余腺泡和扩张导管中也高表达。此外，PRR 和自噬标志物在慢性下颌下腺唾液腺炎组织和 HSG 细胞中明显共定位。
TLR4 和 NOD2 在唾液腺中有独特的表达部位，它们可能在炎症条件下协同激活唾液腺中的自噬。
