Receptor interaction protein 3 mediated the recruitment of hepatic monocytes/macrophages in autoimmune hepatitis / 中华消化杂志

ABSTRACT

Objective:To explore the role of receptor-interaction protein 3 (RIP3) in regulating the infiltration of monocytes/macrophages into the liver in autoimmune hepatitis (AIH).Methods:From January to June in 2018, at Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, 10 AIH patients who underwent liver biopsy were enrolled, and at the same time, 5 age and gender matched individuals with normal liver function and hepatic cyst were selected as control. The infiltration of monocytes/macrophages in the liver tissues was observed by immunofluorescence detection in the patients with AIH and controls. Raw264.7 macrophages were divided into control group, lipopolysaccharide group and lipopolysaccharide+ RIP3 inhibitor GSK872 (GSK872) group. The expression of RIP3, mixed lineage kinase domain like pseudokinase ( MLKL), tumor necrosis factor ( TNF)- α, interleukin ( IL)-6, IL-1 β, nod-like receptor protein 3 ( NLRP3), CC motif chemokine ligand ( CCL)2 and CCL5 at mRNA levels were detected by quantitative polymerase chain reaction (qPCR). Raw264.7 macrophages were also divided into control group, lipopolysaccharide group and lipopolysaccharide + dexamethasone group. The relative expression of TNF- α, NLRP3, RIP3 and MLKL at mRNA level in macrophage were detected by qPCR. Twenty-four 6-week-old female C57BL/6 mice were chosen to establish AIH mice model and were randomly divided into control group, concanavalin A (ConA) group, ConA+ dexamethasone group and ConA+ GSK872 group (6 mice in each group). After the mice were executed, the peripheral blood and liver tissues were collected. The histopathology of mice liver were observed and the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were measured. The expression of CCL2 and CC motif chemokine receptor 2 ( CCR2) at mRNA level were detected by qPCR. The proportion of macrophages in mice livers were analyzed by flow cytometry. The independent sample t test and one-way analysis of variance were performed for statistical analysis. Results:The percentages of CD68 positive macrophages and MAC387 positive infiltrated mononuclear macrophages in livers of AIH patients were both higher than those of controls ((0.84±0.21)% vs. (0.09±0.03)%, (0.79±0.13)% vs. (0.03±0.01)%), and the differences were statistically significant ( t=3.00 and 4.84; all P<0.05). The expression of RIP3, MLKL, TNF- α, IL-6, IL-1 β, NLRP3, CCL2 and CCL5 at mRNA level of lipopolysaccharide group were all higher than those of control group and lipopolysaccharide+ GSK872 group (1.64±0.16 vs. 1.07±0.07 and 0.63±0.11; 10.45±1.37 vs. 1.10±0.33 and 1.51±0.63; 5.43±0.59 vs. 0.94±0.06 and 2.59±0.45; 204.20±30.73 vs. 1.26 ±0.19 and 111.40±11.62; 20 848.00±362.00 vs. 1.09 ±0.26 and 10 940.00±566.60; 7.47±1.17 vs. 1.09±0.09 and 3.79±0.89; 68.03±5.15 vs. 1.14±0.19 and 14.09±2.62; 5 935.12±96.20 vs. 1.43±0.46 and 673.50±49.10), and the differences were all statistically significant ( t=3.11, 5.21, 6.65, 6.55, 7.57, 3.96, 6.60, 3.06, 8.83, 4.08, 5.46, 2.56, 12.97, 10.16, 25.34 and 14.99; all P<0.05). The expression of TNF- α, NLRP3, RIP3 and MLKL at mRNA level of lipopolysaccharide group were all higher than those of control group and lipopolysaccharide+ dexamethasone group (8.85±1.43 vs. 1.44±0.43 and 3.63±0.63; 6.42±0.86 vs. 0.99±0.12 and 2.07±0.17; 1.72±0.21 vs. 0.93±0.09 and 0.43±0.07; 6.87±0.85 vs. 1.62±0.31 and 1.41±0.29), and the differences were all statistically significant ( t=4.95, 3.33, 6.24, 4.95, 3.04, 5.11, 5.77 and 6.07, all P<0.05). The mice liver of ConA group showed obviously inflammatory cells infiltration and hepatocytes necrosis. The serum ALT and AST levels of ConA group were both higher than those of control group, ConA+ dexamethasone group and ConA+ GSK872 group ((2 569.00±45.44) U/L vs. (49.38±9.07), (103.00±14.07) and (759.30±34.99) U/L; (3 335.00±88.79) U/L vs. (108.50±18.10), (460.00±97.40) and (1 573.85±36.06) U/L), the serum ALT and AST levels of ConA+ dexamethasone group were both lower than those of ConA+ GSK872 group, and the differences were all statistically significant ( t=5.54, 5.42, 3.90, 4.63, 4.16, 3.79, 6.70 and 2.71; all P<0.05). The expression of CCL2 and CCR2 at mRNA levels in mice liver of ConA group were both higher than those of control group, ConA+ dexamethasone group and ConA+ GSK872 group (92.64±10.57 vs. 0.78±0.15, 5.64±1.00 and 9.47±2.06; 5.73±0.39 vs. 0.98±0.22, 2.18±0.22 and 2.98±0.33), and the differences were all statistically significant ( t=7.66, 7.24, 5.87, 8.71, 8.58 and 5.45; all P <0.01). The proportion of CD45 + CD11b + F4/80 + total macrophages and CD45 + CD11b hiF4/80 lo infiltrated macrophages in mice livers of ConA group were both higher than those of control group, ConA+ dexamethasone group and ConA+ GSK872 group (0.86±0.02 vs. 0.73±0.03, 0.68±0.02 and 0.72±0.03; 0.56±0.02 vs. 0.08±0.02, 0.11±0.01 and 0.08±0.01), however the proportion of CD45 + CD11b loF4/80 hi liver macrophages (Kupffer cells) was lower than those that of control group, ConA+ dexamethasone group and ConA+ GSK872 group (0.24±0.03 vs. 0.58±0.04, 0.52±0.07 and 0.56±0.07), and the differences were all statistically significant ( t=4.27, 5.90, 3.89, 18.70, 19.87, 20.52, 7.35, 3.82 and 3.87, all P<0.05). Conclusions:The number of macrophages incread in the livers of AIH patients. RIP3 signaling mediates the migration of monocytes/macrophages infiltration in immune hepatitis, which may be a potential therapeutic target for AIH.