title: Nicastrin mutations in familial acne inversa impact keratinocyte proliferation and differentiation through the Notch and phosphoinositide 3-kinase/AKT signalling pathways.
abstract: BACKGROUND
  Acne inversa (AI) is a chronic inflammatory skin disease with an autosomal dominant inheritance pattern. Mutations of the gene encoding nicastrin (NCSTN), a cofactor subunit of γ-secretase, are responsible for familial AI. However, whether deficiency of nicastrin is functionally implicated in the biological behaviours of human keratinocytes and related molecular mechanisms remains unknown.
  
  
  OBJECTIVE
  To study alterations of biological traits and related signalling pathways modulated by nicastrin knockdown in keratinocytes.
  
  
  METHODS
  A human immortalized keratinocyte cell line (HaCaT) was treated with efficient small interfering (si)RNA-targeted NCSTN. Cell proliferation was measured by CCK-8 assay; cell-cycle and cell apoptosis analyses were detected by flow cytometry. Microarray analysis was applied to uncover impacts of NCSTN silencing on whole-genome expression of HaCaT cells. Altered signalling pathways were further confirmed by real-time polymerase chain reaction, Western blotting and immunohistochemistry in both HaCaT cells and lesions of a patient with AI with NCSTN mutation.
  
  
  RESULTS
  NCSTN knockdown in HaCaT cells impaired γ-secretase activity, leading to increased cell proliferation and S-phase population. Microarray data also showed that numerous genes and pathways implicated in proliferation and differentiation of keratinocytes were statistically changed. Among these genes, expression levels of several Notch pathway molecules, known as γ-secretase substrates, were validated to be significantly attenuated in both nicastrin-silencing HaCaT cells and the lesion of the patient. Furthermore, a remarkable elevation of expression of phosphoinositide 3-kinase (PI3K), AKT and its activated form pAKT was illustrated in siRNA-treated HaCaT cells.
  
  
  CONCLUSIONS
  Deficiency of the NCSTN in familial AI may regulate proliferation and differentiation of keratinocytes mainly through the Notch and PI3K/AKT signalling pathways.
authors.affiliation: Institute of Dermatology, Chinese Academy of Medical Sciences, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.
authors.forename: X
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Institute of Dermatology, Chinese Academy of Medical Sciences, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.affiliation: Institute of Dermatology, Chinese Academy of Medical Sciences, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.affiliation: Institute of Dermatology, Chinese Academy of Medical Sciences, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Institute of Dermatology, Chinese Academy of Medical Sciences, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.affiliation: Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, St 12 Jiangwangmiao, Nanjing, Jiangsu, 210042, China.|Institute of Plastic Surgery, Chinese Academy of Medical Sciences, St 33 Ba-Da-Chu Road, Beijing, 100144, China.
authors.forename: B
authors.initials: B
authors.lastname: Wang
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics*; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle; D049109:Cell Proliferation; D055785:Gene Knockdown Techniques; D017497:Hidradenitis Suppurativa / Q000235:genetics*; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D046888:Tissue Array Analysis; D055815:Young Adult
chemical_list: D008562:Membrane Glycoproteins; D034741:RNA, Small Interfering; D051880:Receptors, Notch; C413604:nicastrin protein; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D053829:Amyloid Precursor Protein Secretases