title: Upregulation of blood proBDNF and its receptors in major depression.
abstract: BACKGROUND
  In recent decades, the role of brain-derived neurotrophic factor (BDNF) in depression has received intensive attention. However, the relationship between proBDNF and depression has not been clearly elucidated.
  
  
  METHODS
  Forty drug-free women patients diagnosed with major depression and 50 healthy female controls were enrolled in our study. Peripheral blood was sampled from all the subjects. With the blood samples, we assessed the relationship between BDNF and major depression from following aspects: the levels of BDNF, proBDNF and their receptors in the sera and lymphocytes. The mRNA levels of these factors in lymphocytes were also examined. Furthermore, the correlations between each factor and the severity of major depression were tested.
  
  
  RESULTS
  It was found that: (a) the protein and serum levels of proBDNF, sortilin and p75NTR were higher in major depressive patients than in healthy controls while mature BDNF and TrkB levels were lower; (b) the BDNF, TrkB, sortilin and p75NTR mRNA levels changed in line with their protein levels; (c) The levels of mature BDNF and TrkB had negative correlations with the major depression severity, and the levels of proBDNF, p75NTR and sortilin were positively correlated with the scores of HRSD-21; (d) the ratio of proBDNF and mBDNF was imbalanced in major depressive patients.
  
  
  CONCLUSIONS
  The balance between the proBDNF/p75NTR/sortilin and mBDNF/TrkB signaling pathways appears dysregulated in major depression and both pathways should be considered as biomarkers for the major depression
  
  
  CONCLUSIONS
  More cases on both genders should be enrolled in our study. And further works on the mechanisms of how BDNF and its receptors are regulated in depression should also be carried out.
authors.affiliation: Key Laboratory of Stem Cells and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University, Kunming, Yunnan Province, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Xiong
authors.forename: Yoon
authors.initials: Y
authors.lastname: Lim
authors.forename: Ye
authors.initials: Y
authors.lastname: Ruan
authors.forename: Chaohong
authors.initials: C
authors.lastname: Huang
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Zhu
authors.forename: Jin-hua
authors.initials: JH
authors.lastname: Zhong
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Xiao
authors.forename: Xin-Fu
authors.initials: XF
authors.lastname: Zhou
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000097:blood; D000328:Adult; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis / Q000097:blood*; D002681:China; D003865:Major Depressive Disorder / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000097:blood; D011498:Protein Precursors / Q000096:biosynthesis / Q000097:blood*; D012333:RNA, Messenger / Q000096:biosynthesis; D020813:Receptor, trkB / Q000096:biosynthesis / Q000097:blood*; D017475:Receptors, Nerve Growth Factor / Q000096:biosynthesis / Q000097:blood; D015398:Signal Transduction; D015854:Up-Regulation; D055815:Young Adult; D000099183:Sortilin
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D019208:Brain-Derived Neurotrophic Factor; D009419:Nerve Tissue Proteins; D011498:Protein Precursors; D012333:RNA, Messenger; D020813:Receptor, trkB; D017475:Receptors, Nerve Growth Factor; D000099183:Sortilin; C484065:NGFR protein, human; C426674:brain-derived neurotrophic factor precursor
keywords: Brain-derived neurotrophic factor; Major depression; Sortilin; TrkB; p75NTR; proBDNF