ABSTRACT
Fibroblast growth factor 21 (FGF21) acts as an anti-atherosclerotic agent. However, the specific mechanisms governing this regulatory activity are unclear. Autophagy is a highly conserved cell stress response which regulates atherosclerosis (AS) by reducing lipid droplet degradation in foam cells. We sought to assess whether FGF21 could inhibit AS by regulating cholesterol metabolism in foam cells via autophagy and to elucidate the underlying molecular mechanisms. In this study, ApoE-/- mice were fed a high-fat diet (HFD) with or without FGF21 and FGF21 + 3-Methyladenine (3MA) for 12 weeks. Our results showed that FGF21 inhibited AS in HFD-fed ApoE-/- mice, which was reversed by 3MA treatment. Moreover, FGF21 increased plaque RACK1 and autophagy-related protein (LC3 and beclin-1) expression in ApoE-/- mice, thus preventing AS. However, these proteins were inhibited by LV-RACK1 shRNA injection. Foam cell development is a crucial determinant of AS, and cholesterol efflux from foam cells represents an important defensive measure of AS. In this study, foam cells were treated with FGF21 for 24 hours after a pre-treatment with 3MA, ATG5 siRNA or RACK1 siRNA. Our results indicated that FGF21-induced autophagy promoted cholesterol efflux to reduce cholesterol accumulation in foam cells by up-regulating RACK1 expression. Interestingly, immunoprecipitation results showed that RACK1 was able to activate AMPK and interact with ATG5. Taken together, our results indicated that FGF21 induces autophagy to promote cholesterol efflux and reduce cholesterol accumulation in foam cells through RACK1-mediated AMPK activation and ATG5 interaction. These results provided new insights into the molecular mechanisms of FGF21 in the treatment of AS.
Subject(s)
Atherosclerosis/metabolism , Autophagy , Cholesterol/metabolism , Fibroblast Growth Factors/metabolism , Receptors for Activated C Kinase/metabolism , ATP Binding Cassette Transporter 1/metabolism , Adenine/analogs & derivatives , Adenine/metabolism , Adenine/pharmacology , Animals , Apolipoproteins E , Autophagy-Related Protein 5/metabolism , Beclin-1/metabolism , Foam Cells/metabolism , Lipids/chemistry , Male , Mice , Mice, Transgenic , Up-RegulationABSTRACT
To explore the differentiation of gastrointestinal stromal tumor(GIST) with synchronous carcinoma clinical and pathological features,diagnosis and differential diagnosis.Methods Clinical characteristics,pathological morphology and immunohistochemical staining were observed in 9 cases of GIST with synchronous carcinoma,with review of the relevant literature.Results Microscopically,in 4 cases GIST with esophageal carcinoma,most of tumor cells in central focus were squamous cells and keratin pearls which were well differentiated and the rest of tumor cells are basal like cells on the edge.In the other 5 cases (4 of them with gastric carcinoma and 1 with rectal cancer).Microscopically,the tumors were composed of dysplastic glands which presented as adenoid structures and poorly differentiated.The majority of gastric GIST were spindle cell tumors,which resembled smooth muscle tumors histologically and showed a variety of histological pattern,such as lace like pattern,palisading pattern,antique coins like pattern and eddy pattern.And a perinuclear vacuolization pattern was common.Immunohistochemistry showed that the tumor cells were positive for CK5/6,CK14 and p53,but negative for S-100,CK7 of the 4 cases GIST with esophageal carcinoma.In the other 5 cases (4 of them with gastric carcinoma and 1 with colorectal cancer),showed that CK7,CK20,CEA and HER-2 were positive and negative for S-100.In all the 9 case of GIST,the tumor cells were positive for CD34,CD117 (+),DOG1 and SMA,but negative for S-100,desmin,etc.Conclusion There are no special clinical symptoms in most of GIST with synchronous carcinoma,because these GISTs are generally incidental findings.The proliferative index of GIST with synchronous carcinoma is observably lower than that of GIST without synchronous carcinoma.Most GISTs with synchronous carcinoma can be treated by the standard treatment for the accompanying carcinoma,and do not need specific additional treatments.
ABSTRACT
PurposeTo study the possibility of transferring decorin gene to rat glomerular mesangial cell. Methods Amplification of the rat decorin (DCN) eDNA by RT-PCR for constructing the plasmid pcDNA3.1A-DCN and lipofectin method for transfecting DCN gene into MsC; G418 scanning, Western blot and RT-PCR analysis for detecting DCN protein and mRNA in D-A6 cell clone.Results The recombinant eukaryotic expression plasmid, pcDNA3.1A-DCN was successfully constructed and 2 cell clones positively expressing DCN were selected. ConclusionsThese cell clones positively expressing DCN is valuable for providing favorable experimental bases of gene therapy to model with glomerular diseases.