Summary: Running-Induced Systemic Cathepsin B Secretion Is Associated With Memory Function

Read the summary and the most important questions on Running-induced systemic Cathepsin B secretion Is Associated with Memory function

• 1 Summary

• What is Cathepsin B?

  It is a protein, secreted after endurance muscle activity, that may be important in the cognitive and neurogenic effects of Running.

• Which downstream pathway seems to be involved in CTSB secretion?

  The AMPK pathway, which is induced after endurance exercise.

• What was the effect of CTSB on adult hippocampal progenitor cells in vitro?

  • Enhanced BDNF expression
  • Enhanced DCX expression

• 2 Introduction

• What are the thought effects of exercise on (human) brain function?

  • improved cognition in humans
  • enhance neurotrophic factor expression
  • increased vascularisation
  • improved memory and neurogenesis in the hippocampus

• Name some peripheral factors linked to running that may positively influence brain function.

  • Blood factors from young animals enhance brain plasticity in older animals (Katsimpardi et al., 2014)
  • myokines derived from muscles may influence neural pasticity (PGC1a -> FNDC5 -> irisin -> enhanced hippocampal BDNF; Wrann, 2015)

• What are investigated myokines named in this study?

  • Cathepsin B
  • Irisin

• What did the authors investigate?

  Proteomics analyses of cultured medium in AMPK stimulated myoblasts. They became particulary interesting in Cathepsin C as it may play an important role in the effects of exercise on Human Brain.

• 3 Results

• 3.1 Identification and Validation of Candidates

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• Which myokine did they choose to investigate after proteomics analysis?

  Cathepsin B (CTSB)

• 3.2 Validation of CTSB expression after exercise

• How was the expression of CTSB by myoblasts validated?

  • after 8 days of differentiation the cells were starved for 3 hrs by serum free media. 
  • AICAR (AMPK agonist) or vehicle was added for different durations, increasing gene expression in the 3hrs. 
  • extracellular protein levels were increased in differentiated L6 myoblasts
    
  • running mice (14 and 30 days) had increasing blood CTSB
  • CTSB expression and secretion in running mice was only found in skeletal muscle (fast twitch)

• On which levels of action did the authors validate the myokine CTSB?

  • Induction by substance
  • Gene expression (both vivo and vitro)
  • Protein expression (both vitro and vivo)
  • Time duration
  • Location of secretion