The Influence Of Smoking On Proteins In Nod1 Signalling Pathway And Defense Ability Of Oral Mucosa Epithelial Cells

Chapter 1The relationship of smoking with the expression of important proteins of Nod1 signalling pathway in oral squamous cell carcinomaObjective:Oral squamous cell carcinoma (OSCC) is the most common oral malignant tumor. It’s well known that smoking plays a significant role in OSCC and it affects innate immune. But the internal mechanism remains unclear. Nod1 signalling pathway is an important part of innate immune which mediates the defense reaction of oral mucosa. The Nod1 signalling pathway includes Nod1, Rip2, NF-κB proteins. Caspase-12 is one of the important Nod1 signalling pathway regulatory factors. Studies have shown that smoking has certain relevance with Caspase-12. This experiment is to study the relationship of smoking with the expression of those key proteins in OSCC and its clinical pathological significance.Methods:The expression of Nod1 signalling pathway proteins was detected in 25 OSCC samples by Western blot. The samples are devided into smoking group (11 samples) and non-smoking group (14 samples).Results:We found that smoking group expressed more Rip2, Caspase-12 and less Nod1, NF-κB proteins relative to non-smoking group. There was statistical significance in these proteins.Conclusions:From the results, we can reach a conclusion that smoking may elevate the expression of Caspase-12 protein and reduce the expression of Nod1 protein, then affect the Nod1 signalling pathway and weaken the innate immunity. Smoking plays an important role in the development of OSCC.Chapter 2 The influence of smoking on human beta-defensins secrected by oral mucosa epithelial cellsObjective:Human defensins belong to a family of endogenous antimicrobial peptides. Their contribution to the host defense against microbes is well known and they also play an important role in innate immunity. Oral epithelial tissue express human beta-defensin (hBD). Oral leukoplakia (OLK) is a common oral precancerous lesion in clinic. Smoking is one of the risk factors for malignant transformation of OLK. This paper is mainly to investigate the potential effects of cigarette smoke on oral immune defense, especially the expression of hBD.Methods:In this study, a commercially available smoking chamber for exposing cultured leukl cells at the air-liquid interface has been used. Cells are divided into two groups: smoking group(exposed to cigarette smoke for 5 min,10 min,20 min,40 min) and control group(exposed to 5%CO2 for 10 min). The level of hBD is detected by ELISA.Results:hBD1 in smoking group was significantly lower than in control group (P=0.004), however hBD2 expression in smoking group increased compared with those in control group (P=0.012), and in the two groups the level of hBD3 had no statistical difference.Conclusions:Smoking may change hBD expression of oral mucosa, and then influence the defense immunity.