Role Of Endoplasmic Reticulum Stress In The Autophagy Of Alveolar Macrophages In Patients With Silicosis

Objectives Pneumoconiosis especially silicosis is the most serious occupational disease which could hazard occupational people in our country, It has been found that there is a connection between endoplasmic reticulum stress, dysfunction of autophagy and many diseases like organ fibrosis, IRE1-XBP1, PERK-e IF2α and ATF6 signaling pathways of ERS could induce autophagy. But direct evidencde explain the relationship between ERS-autophagy and silicosis fibrosis has not found. This study added 3 UPR signaling inhibitors to explore whether ERS caused by the stimulation of free Si O2, autophagy activity intensity in AM of different silicosis period and the change of ERS level with western blot and RT-PCR technique, which provide new theoretical basis for the research of silicosis pathogenesis.Methods Using simple random sampling method, 76 cases of male patients with silicosis received whole lung lavage treatment in Beidaihe Coal Workers’ Sanatorium as the research objects. All of the research objects were diagnosed by experts according to GBZ 70—2009 "standard of pneumoconiosis diagnosis", and design reasonable questionnaire according to the purpose of this study, the questionnaire included the general information, history of employment, history of exposed to dust, history of diseases and history of smoking, etc. Laboratory research: Bronchoalveolar lavage fluid(BALF) collected from dopey research objects was filtered, centrifuged and then AMs were separated and purified. Cells were divided into four groups: Untreated group(the control group, only containing medium), ATF6 inhibitor group, PERK inhibitor group and IRE1 inhibitor group. AMs were harvested after cultured for 24 h. The expression pattern and effect of GRP78, Beclin1 and LC3 proteins and m RNA were detected using western blot method and RT-PCR technique.Results 1 The expression pattern of 3 interest proteins in different stages of untreated group: Relative expression levels of 3 proteins in stage Ⅰ, stage Ⅱ and stage Ⅲ were higher than those in observed subjects(P<0.05), stage Ⅱ and stage Ⅲ were higher than those in stageⅠgroup(P<0.05). GRP78 in stage Ⅲ was lower than that in stage Ⅱ(P<0.05); Beclin1 and LC3 proteins in stage Ⅲ were higher than those in the stage Ⅱ group(P>0.05). 2 Influence factor of interest protein in AMs: Our study found that the relative expression of Beclin1 and LC3 proteins in the group of dust exposure(≥ 15yr) were more than that in the group of dust exposure(<15yr), the difference was statisticalsignificant(P>0.05). The relative expression of GRP78 in start ages exposed to dust ≥25yr was higher than that in <25yr(P>0.05). The relative expression of 3 proteins in escape from dust group were higher than those in unescape from dust group. The expression level of GRP78 protein associated with smoking index(P<0.05). 3 The expression level of interest proteins and m RNA: the expression pattern of Beclin1 and LC3 proteins increased with the deterioration of silicosis. 3 interest proteins in stage Ⅲ of 3 inhibitors groups were higher than those in observed subjects(P<0.05); GRP78 protein level in stage Ⅰ and stage Ⅲ of 3 inhibitors groups was lower than those of untreated group; Beclin1 protein level in stage Ⅱ and stage Ⅲ of 3 inhibitors groups was lower than those of untreated group; LC3 protein level in stage Ⅰ, stage Ⅱ and stage Ⅲ of 3 inhibitors groups was lower than those of untreated group; those differences above have statistical significant(P<0.05). 4 The expression levels of 3 m RNAs among different groups.The relative expression level of GRP78 m RNA and Beclin1 m RNA in stage Ⅱ and stage Ⅲ was higher than that in observed subjects(P<0.05), The relative expression levels of GRP78 m RNA and Beclin1 m RNA in 3 inhibitors groups were lower than those in untreated group(P<0.05); The difference of Beclin1 m RNA in stage Ⅰ between IRE1 inhibitor group and GRP78 m RNA in stage Ⅱ between IRE1 inhibitor group and the untreated group have statistical significant.Conclusions 1 Endoplasmic reticulum stress could occured in alveolar macrophages of silicosis patients and become more serious accompanied with the development of the silicosis. 2 Autophagy degree in alveolar macrophages was increased with the deterioration of silicosis. 3 Endoplasmic reticulum stress and autophagy in alveolar macrophages alleviated after the 3 pathway of endoplasmic reticulum stress were suppressed, which indicated endoplasmic reticulum stress signaling pathway plays important role in regulate with autophagy in alveolar macrophages of silicosis patients.