Overexpression Of JAZF1Reduces Proinflammation Cytokines In Liver Release Via Inhibition Of Stress Kinases And NF-κB

PART ONEEFFECTS OF OVEREXPRESSION OF JAZF1ON THEEXPRESSION OF HEPATIC PROINFLLAMATORYCYTOKINES INDUCED BY SATURATED FATTY ACIDSAND ITS POTENTIAL MECHANISMSObjective To explore the effects of overexpression of JAZF1on theexpressions of palmitate induced hepatic pro-inflammatory cytokines andits mechanisms.Methods The model of hepatocytes steatosis was constructed byincubating with PA in various concentrations for indicated times. Therecombinant adenovirus expressing JAZF1(Ad-JAZF1) was used toup-regulate expression of the JAZF1. The triglyceride in hepatocytes wasmeasured by using GOD. The cell viability was detected by CCK-8. ThemRNA expressions of TNF-α, MCP-1, IL-8and JAZF1in hepatocyteswere examined by RT-PCR. The protein levels of TNF-α, MCP-1and IL-8 secreted by hepatocytes were assayed by ELISA. The expressions ofP-JNK, P-P38MAPK, P-ERK, IKBα and JAZF1were detected throughusing western blot.Result Palmitatic acid significantly increased TNF-α, MCP-1and IL-8mRNA expressions in IAR-20hepatocytes in a dose-and time-dependentmanner（P<0.01or P<0.001）. Palmitatic acid obviously elevated theactivities of P-JNK、P-P38MAPK、P-ERK,while PA decreased theexpression of IKBα protein（P<0.05or P<0.01）.Furthermore, treatmenthepatocytes with stress kinases inhibitors inhibited PA-induced theactivatation of JNK,P38MAPK, ERK and NF-κB pathways and theexpressions of TNF-α, MCP-1and IL-8in these cells（P<0.05or P<0.01）.Additionally, the expression of JAZF1mRNA and protein were markedlyincreased in hepatocytes infected with Ad-JAZF1（P<0.01or P<0.001）.However, in JAZF1treated cells, decreased expressions of TNF-α, MCP-1and IL-8were accompanied by decreased p38AMPK and JNKphosphorylation and increased IκB α protein, similar to the role ofsignaling inhibitors（P<0.05or P<0.01）.Conclusion Saturated fatty acids promote the expressions of TNF-α,MCP-1and IL-8by activating the signaling pathways of JNK, P38MAPK,ERK and NF-κB. JAZF1overexpression in vitro can protect againstPA-induced inflammatory responses through an inhibition of the stressprotein kinases activities. This information is of potential importance in drug development programs using JAZF1as a therapeutic target forNAFLD. PART TWOTHE EFFECTS OF JAZF1OVEREXPRESSION ONTHE LEVELS OF HIGH FAT DIET-INDUCEDPROINFLAMMATORY FACTORS IN LIVER AND ITSPOTENTIAL MECHANISMSObjective To determine the effects of overexpression of JAZF1on thelevels of pro-inflammatory factors in liver and its mechanisms.Method20normal3-week old male C57BL/6J mice and20normal3-week old male JAZF1transgenic (JAZF1-Tg) mice derived fromC57BL/6J mice were randomly divided into four groups include wide-typegroup fed by normal chow (NC group, n=10), wide-type group fed by highfat diet (HF group, n=10), JAZF1-Tg group fed by normal chow (NJ group,n=10) and JAZF1-Tg group fed by high fat diet(HJ group, n=10) afteradaptive feeding for one week. After establishment of model for12weeks,the circulation levels of fasting glucose, total cholesterol, triglyceride, freefatty acids, alanine aminotransferase and the triglycerides in liver tissueswere detected by using enzymatic cycling methods. The concentration of insulin in plasma was detected by enzyme immunoassay. The mRNAexpressions of TNF-α, MCP-1, IL-8and JAZF1in liver were examined byRT-PCR. The expressions of P-JNK, P-P38MAPK, P-ERK, IKBα andJAZF1were detected through using western blot.Results The weight, fasting plasma glucose (FBG), fasting plasma insulin(Ins), triglycerides, total cholesterol, free fatty acids(FFA)and alanineaminotransferase and the hepatic triglyceride were significantly increasedin high fat diet-fed group compared with normal chow diet-fed group(P<0.05or P <0.01). However, the FBG, INS, TC and ALT in HJ groupwere lower than that in HF group (P<0.05or P <0.01). The food intakewas no significance statistics among difference groups (P>0.05). Asexpected, the mRNA and protein expression of JAZF1were markedlyincreased in JAZF1-Tg mice compared with WT mice (P<0.01orP<0.001). Furthermore, the mRNA expressions of TNF-α, MCP-1andIL-8were significantly increased in HF group than that in NC group,while the mRNA expressions of TNF-α, MCP-1and IL-8were obviouslydecreased in HJ group than that in HF group(P<0.01or P<0.001).Additionally, HFD-feeding (HF group) significantly increasedphosphorylation of p38MAPK, ERK1/2and JNK and aggravated capacityto degrade IκB α in the liver (P<0.01), whereas the changes of p38MAPK,JNK phosphorylation and IκB α abundance were less obvious inHFD-fed JAZF1-Tg mice(HJ group) than in HFD-fed WT mice(HF group) (P<0.05or P<0.01). However, the phosphorylation of ERK1/2wasunchanged between HJ group and HF group (P>0.05).Conclusion Over-expression of JAZF1can obviously decrease theexpression of HFD-induced pro-inflammatory cytokines vivo. Thisattenuation was accompanied by the decreased activation of JNK, p38MAPK and NF-κ B. These data provide evidence for the important role ofJAZF1in preventing the development of NAFLD and systemicinflammation related disease.