title: AGEs trigger autophagy in diabetic skin tissues and fibroblasts.
abstract: OBJECTIVE
  Accumulation of advanced glycation end products (AGEs) contributes to the development of diabetic ulcers. Recent evidence indicates that AGEs administration enhanced autophagy in many cell types. As a positive trigger of autophagy, the effect of AGEs on autophagy in skin tissues and fibroblasts remains unknown.
  
  
  METHODS
  Skin tissues were isolated from Spreqne-Dawley rats and immunohistochemical staining was performed to analyze the location of LC3 and FOXO1 in skin tissues. Then primary cultured foreskin fibroblast cells with treated with AGEs and the effect of AGEs on autophagy was investigated. Protein level expressions of LC3, Beclin-1 and FOXO1 in fibroblasts were analyzed by Western blotting. Autophagic flux is detected with autophagy inhibitor chloroquine and mRFP-GFP-LC3 tandem construct.
  
  
  RESULTS
  Compared with skin from normal rats, immunohistochemical staining shows a predominant LC3 localization in fibroblasts cytoplasm in diabetic rats. Elevated expression of FOXO1 also existed in diabetic rats dermis fibroblasts when compared with normal rats in immunohistochemical analysis. In human skin fibroblasts cells, AGEs administration stimulated the autophagy related LC3-II/LC3-I and Beclin-1 expressions and increased autophagy flux. In mRFP-GFP-LC3 puncta formation assays, both autolysosome and autophagosome were increased in human fibroblasts after treatment with AGEs. Fibroblasts exposed to AGEs also have increased FOXO1 expression compared with control group.
  
  
  CONCLUSIONS
  AGEs could induce autophagy at least in part via regulating the FOXO1 activity in diabetic skin tissues and fibroblasts.
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Kan
authors.initials: K
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Guojuan
authors.initials: G
authors.lastname: Lao
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Lifang
authors.initials: L
authors.lastname: Mai
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Yan
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China. Electronic address: 13640242307@139.com.
authors.forename: Chuan
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, 107 Yanjiang West Road, Guangzhou 510120, PR China. Electronic address: renmeng80@139.com.
authors.forename: Meng
authors.initials: M
authors.lastname: Ren
mesh_terms: D001343:Autophagy / Q000187:drug effects*; D002478:Cells, Cultured; D048909:Diabetes Complications / Q000378:metabolism* / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000378:metabolism; D017127:Glycation End Products, Advanced / Q000008:administration & dosage*; D006801:Humans; D012867:Skin / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D017127:Glycation End Products, Advanced
keywords: AGEs; Autophagy; Diabetic ulcers; FOXO1; Skin fibroblasts