Errα Promotes Porcine Preadipocytes Adipogenesis By Inhibiting β-Catenin

Adipogenesis has been one of the most intensively studied model of cellulardifferentiation and it is a complex process that collaboratively regulated by multi-factor andmulti-stage, in which both Errα and wnt/β-catenin signaling pathway play curcial roles.Beta-catenin plays a key role in the wnt signaling pathway as an intracellular secondmessengers. There are many results from Errα and wnt/β-catenin signaling pathway onadipogenesis, but only a few explored their interactions.Recently study have found that in cancer cells, ERRα alone could inhibit wnt/β-cateninsingaling pathway, when ERRα together with its cofactor PGC-1α to regulate, it can promotewnt/β-catenin singaling pathway. But no researches have found ERRα have function on whichfactor of the wnt singaling pathway, and the crosstalk on the adipogenesis has not reported.In present work,1-3days piglets was used as our experimental animals and porcinepreadipocytes was separated and cultured. Western Blot and RT-PCR analysis was used todetect the expression of ERRα and β-catenin during adipogenesis. We used β-cateninretrovirus plasmid and ERRα adenovirus plasmid to package β-catenin retrovirus and ERRαadenovirus in293T and293A cells seperately, and infected porcine preadipocytes.Immunofluorescence was used to detect ERRα and β-catenin expression. And the specificactivator of β-catenin, LiCl and the specific inhibitor of ERRα, XCT790was used the treatedthe porcine preadipocytes. Western Blot was used to detected the expression of ERRα of thepreadipocytes treating with ERRα adenovirus and specific inhibitor XCT790. The culturedporcine preadipocytes were divided into five groups and there were ERRα adenovirus infectedgroup, ERRα adenovirus infected and LiCl treated group, LiCl treated group, XCT790groupand control. Oil-Red-O was used detected the formation of droplet in five groups. What'smore, Western Blot and RT-PCR was used to detected the expression of ERRα, β-catenin andthe adipogenic maker gene, SREBP-1c. In a word, we have concluded the crosstalk betweenERRα and β-catenin during adipogenesis. The main results are as follows:1. β-catenin retroviral vector packaging produced β-catenin retrovirus, but the virus titeris too low to infect porcine preadipocytes. The ERRα adenovirus vector packaging producedERRα adenovirus and had a high virus titer to infect the porcine preadipocytes effectively. 2. Western Blot and RT-PCR results showed that during adipogenesis, ERRα andSREBP-1c up regulated, while β-catenin down regulated. There may exist crosstalk betweenERRα and β-catenin during adipogenesis.3. Western Blot results showed that the produced ERRα adenovirus promoted expressionof ERRα while10umol/L XCT790inhibited ERRα protein expression.4. Oil-Red-O results showed that the ERRα promoted lipid droplet formation, and LiClinhibited lipid droplets formation. In the group of ERRα adenovirus infection and LiCltreatment, compared with the control group, lipid droplets formation was inhibitedsignificantly.5. Western blot results showed that during adipogenesis, LiCl stabilized β-cateninexpression and inhibited SREBP-1c expression, ERRα adenovirus inhibited β-Cateninexpression and promote SREBP-1c expression. RT-PCR results showed that LiCl was not ableto promote β-catenin mRNA expression, while ERRα could inhibit the β-Catenin mRNAexpression.In summary, during adipogenesis, ERRα inhibited β-Catenin expression, therebyinhibited the role of the wnt/beta-catenin signaling pathway on the adipogenesis. Theβ-catenin retroviral vector packaging retroviral titer was too low, and some effective wayneeded to improve viral titer in order to effectively infect porcine preadipocytes.