title: Electric field-induced suppression of PTEN drives epithelial-to-mesenchymal transition via mTORC1 activation.
abstract: BACKGROUND
  Naturally occurring electric fields (EFs) are an intrinsic property of wounds. Endogenous EFs in skin wounds play critical roles in the dynamic and well-ordered biological process of wound healing. The epithelial-to-mesenchymal transition (EMT) allows keratinocytes to transition from sedentary cells to motile cells, facilitating wound healing. However, EMT-related studies have been performed without considering endogenous EFs. Thus, the relationship between electrical signals and the EMT remain elusive.
  
  
  OBJECTIVE
  Phosphatase and tension homolog (PTEN) and mammalian target of rapamycin complex 1 (mTORC1) are key molecules in sensing electrical cues, and they play significant roles in cellular responses to EFs. In addition, these molecules are closely related to the occurrence of the EMT in other cells. We used primary human keratinocytes to investigate the influence of EFs on the EMT as well as the roles of PTEN and mTORC1 in this process.
  
  
  METHODS
  The effects of EFs on the EMT were investigated by analyzing the levels of specific proteins and transcription factors. The roles of mTORC1 and PTEN and their relationship with each other were studied via pharmacological inhibition or genetic knockdown. A Zeiss imaging system and scratch assays were used to study single-cell motility and monolayer cell migration.
  
  
  RESULTS
  EFs induced a range of both biochemical changes (e.g., increased Snail, Slug, vimentin, and N-cadherin expression, decreased E-cadherin expression) and functional changes (e.g., enhanced migratory capacity) that are characteristic of the EMT. EF-stimulated cells exhibited suppressed PTEN expression, and further PTEN downregulation led to the acquisition of more mesenchymal features and the loss of epithelial characteristics, which was accompanied by increased migratory capacity. PTEN overexpression reversed the EF-induced EMT and inhibited the migratory capacity of keratinocytes. EF-induced mTORC1 activation was a required component of the causal relationship between PTEN suppression and the EMT, as mTORC1 inhibition reversed the EMT induced by PTEN downregulation.
  
  
  CONCLUSIONS
  Our data demonstrate that the EF-induced suppression of PTEN drives the EMT via mTORC1 activation, thereby revealing a new and promising role of EFs in facilitating wound reepithelialization. These results provide a novel perspective regarding the significance of EFs in wound healing; therefore, electrical stimulation offers a new avenue of wound management for improved and accelerated wound healing.
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Yan
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Xupin
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Burns and Plastic Surgery, The 205th Hospital of People's Liberation Army, Jinzhou 121001, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Endocrinology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Di
authors.initials: D
authors.lastname: Tang
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Xingyue
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Dongxia
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China.
authors.forename: Jiezhi
authors.initials: J
authors.lastname: Jia
authors.affiliation: Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing 400038, China. Electronic address: yshuangtmmu@163.com.
authors.forename: Yuesheng
authors.initials: Y
authors.lastname: Huang
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D015374:Biosensing Techniques; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D004558:Electric Stimulation; D004560:Electricity; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D000076222:Mechanistic Target of Rapamycin Complex 1; D046912:Multiprotein Complexes / Q000378:metabolism*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D061251:Primary Cell Culture; D015398:Signal Transduction; D000071250:Snail Family Transcription Factors / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D014746:Vimentin / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology*
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; C050361:CDH2 protein, human; D015820:Cadherins; D046912:Multiprotein Complexes; D000071250:Snail Family Transcription Factors; D014746:Vimentin; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: Electric fields; Epithelial-to-mesenchymal transition; Keratinocyte; Migration; PTEN; mTORC1