Modulation of ATP Production Influences Inorganic Polyphosphate Levels in Non-Athletes’ Platelets at the Resting State

Abstract

Platelets produce inorganic polyphosphate (polyP) upon activation to stimulate blood coagulation. Some researchers have linked polyP metabolism to ATP production, although the metabolic linkage is yet to be elucidated. We found evidence for this possibility in our previous study on professional athletes (versus non-athletes), and proposed that the regulatory mechanism might be different for these two groups. To explore this aspect further, we investigated the effects of modulated ATP production on polyP levels. Blood samples were obtained from Japanese healthy, non-athletes in the presence of acid-citrate-dextrose. The platelets in the plasma were treated with oligomycin, rotenone, and GlutaMAX to modulate ATP production. PolyP level was quantified fluorometrically and visualized using 4′,6-diamidino-2-phenylindole. Correlations between polyP and ATP or NADH were then calculated. Contrary to the hypothesis, inhibitors of ATP production increased polyP levels, whereas amino acid supplementation produced the opposite effect. In general, however, polyP levels were positively correlated with ATP levels and negatively correlated with NADH levels. Since platelets are metabolically active, they exhibit high levels of ATP turnover rate. Therefore, these findings suggest that ATP may be involved in polyP production in the resting platelets of non-athletes.

The levels of TGFβ1, VEGF, PDGF-BB, and PF4 in platelet-rich plasma of professional soccer players: a cross-sectional pilot study

“…However, we believe that several other factors modulate the therapeutic potential of PRP through potentiation and suppression and are present in individual PRP preparations [30]. The candidate factor that we have recently paid attention to is polyphosphate (polyP) [31][32][33][34][35][36][37]. PolyP is an ancient, but still mysterious, biopolymer that is produced in the mitochondria in the extension of the ATP production line [33,34,38] and stored in the dense granules of platelets.…”

“…The candidate factor that we have recently paid attention to is polyphosphate (polyP) [31][32][33][34][35][36][37]. PolyP is an ancient, but still mysterious, biopolymer that is produced in the mitochondria in the extension of the ATP production line [33,34,38] and stored in the dense granules of platelets. Upon platelet activation, polyP is released alongside growth factors, and this impacts the immunological functions of platelets in addition to hemostatic function [32].…”

The dynamic relationship between inorganic polyphosphate and adenosine triphosphate in human non‐small cell lung cancer H1299 cells

“…PolyP influences ATP levels in tumor cells by interacting with cellular processes related to energy metabolism, specifically by modulating the activity of ATP synthase, the enzyme responsible for ATP production in the mitochondria [ 21 , 22 ]. Previous studies have shown that polyP can directly interact with ATP synthase, inhibiting its activity and subsequently reducing ATP production [ 20 , 41 ]. In our previous study, we reported that the cellular ATP content did not increase after X‐ray irradiation in polyP‐treated cells, which led to the upregulation of their radiosensitivity [ 12 ].…”

Optimized Protocol for Preservation of Human Platelet Samples for Fluorometric Polyphosphate Quantification

“…In previous studies [7][8][9], pure water was found to be the most suitable solution for platelet suspensions for fluorometric polyP quantification. Furthermore, in a preliminary study, we found that platelet suspensions, including the fixative, produced insoluble compounds after thawing and interfered with polyP quantification.…”

“…To overcome this issue, we optimized the preservation conditions for human platelets based on previously reported quantification methods [7][8][9]. Among several possible protocols, fixation, removal of fixative, replacement with pure water, and preservation at −80 °C appear to be essential elements for successful preservation.…”