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FRI0078 ADENOSINMONOFOSFAT-AKTIVACTIVATING protein kinase (AMFK) – the biopower regulator of an autophagy in rheumatoid arthritis (PA)
  1. VI Shihkin,
  2. GV Kudriavtseva,
  3. VV Shishkin,
  4. YA Malenkov
  1. Saint Petersburg state University, Saint Petersburg, Russian Federation


Background Rheumatoid arthritis is an autoimmune disease characterized by altered cellular homeostasis. A great role of an autophagy is expected in the pathogenesis of these changes.

Objectives To assess the functional activity of AMFK as a strategic biopower regulator of an autophagy and specific indicator of red-ox potential of cells in the sinovial fluid (SF) of patients with rheumatoid arthritis (RA).

Methods SF of knee joints of 7 RA patients with active synovitis and 5 donors were investigated. Activity of enzymes was measured in cytosol of SF cells after ultracentrifugation. Activity of AMFK was estimated with the Western blotting method. The consumption speed of oxygen by SF cells was recorded polarographycally using as the substrate glutamic acid (5 μ mol/ml in incubation fluid). Registration of the active forms of oxygen was carried out by EPR (electronic paramagnetic resonance). Levels of adenylic nucleotides were determined chromatographically.

Results In RA SF we noted activation of AMFK (on average by 2,5 times) at the considerable increase of the AMP level and decrease in ADP and ATP.

Table 1

AMPK activity (units/mg of protein), oxygen uptake rate (OUR, natoms of oxygen/min/mg of protein), the level of active free radical form of oxygen (AFRF, units/mg of protein), the content of adenine nucleotides in SF (nmol/ml) and pH in SF in RA

Conclusions These data demonstrate transition of cells of SF in RA to the energy saving mode of functioning that is followed by strengthening of oxidizing processes, deep dissociation of respiration with oxidizing phosphorylation and sharp increase of oxigen consumption speed by SF cells in vitro against the background of the progressing hypoxia of synovial cells and chondrocytes in vivo. Destabilization of mitochondrial and lysosomal membranes of SF cells appears against the background of shift of pH in RA in more acidic zone. It leads to the reinforced formation of the active forms of oxygen (short-lived toxiferous hydroxyl radicals), shift of red-ox potential of cells, activation of lysosomal hydrolyzing enzymes that forms biochemical mechanisms of development of an autophagy in RA.

Disclosure of Interest None declared

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