Combined activation of the energy and cellular-defense pathways may explain the potent anti-senescence activity of methylene blue

Abstract

Methylene blue (MB) delays cellular senescence, induces complex-IV, and activates Keap1/Nrf2; however, the molecular link of these effects to MB is unclear. Since MB is redox-active, we investigated its effect on the NAD/NADH ratio in IMR90 cells. The transient increase in NAD/NADH observed in MB-treated cells triggered an investigation of the energy regulator AMPK. MB induced AMPK phosphorylation in a transient pattern, which was followed by the induction of PGC1α and SURF1: both are inducers of mitochondrial and complex-IV biogenesis. Subsequently MB-treated cells exhibited >100% increase in complex-IV activity and a 28% decline in cellular oxidants. The telomeres erosion rate was also significantly lower in MB-treated cells. A previous research suggested that the pattern of AMPK activation (i.e., chronic or transient) determines the AMPK effect on cell senescence. We identified that the anti-senescence activity of MB (transient activator) was 8-times higher than that of AICAR (chronic activator). Since MB lacked an effect on cell cycle, an MB-dependent change to cell cycle is unlikely to contribute to the anti-senescence activity. The current findings in conjunction with the activation of Keap1/Nrf2 suggest a synchronized activation of the energy and cellular defense pathways as a possible key factor in MB's potent anti-senescence activity.

Methylene blue does not bypass Complex III antimycin block in mouse brain mitochondria

“…4). However, our data do not support the idea that MB is a universally efficient mitochondriatargeted neuroprotector that can restore mitochondria functions inhibited by multiple agents/conditions [3,12,14] and improve memory and cognitive parameters [15][16][17]. According to our data, MB is only efficient under circumstances of Complex I failure, but not when Complex III is inhibited.…”

Methylene blue elicits non-genotoxic H₂O₂ production and protects brain mitochondria from rotenone toxicity

“…MB had an opposite effect since it increases the NADH oxidation rate. That effect is confirmed by the increased NAD + /NADH ratio 15 minutes after the addition of MB to the cell cultures (Atamna et al, 2015). The increase of the reduced NADH can explain why 1 μM ETC inhibitor causes more mtDNA lesions than 100 μM MB.…”

Potential of Low Dose Leuco-Methylthioninium Bis(Hydromethanesulphonate) (LMTM) Monotherapy for Treatment of Mild Alzheimer’s Disease: Cohort Analysis as Modified Primary Outcome in a Phase III Clinical Trial

“…A concentration of approximately 0.05μM also appears to be adequate for a range of other potentially beneficial effects of the MT moiety such as enhancement of autophagy [ 41 ] and enhancement of mitochondrial function [ 42–49 ]. There is no dose-response for oligomer disaggregation in vitro , and higher doses of LMTM do not result in greater reduction in tau pathology in transgenic mouse models [ 50 ].…”

“…In addition to inhibition of tau aggregation [ 37 ], enhancement of autophagy [ 41 ], and induction of proteotoxic clearance pathways at low concentration [ 51 ], the MT moiety has several pharmacological actions which are consistent with potentially neuroprotective, antioxidant and symptomatic effects [ 46 ]. Enhancement of mitochondrial metabolism [ 42–49 ] has been proposed as a mechanism underlying acute neurocognitive benefits in wild-type rodents [ 46 ] and in healthy young human volunteers [ 46, 52, 53 ]. We show that the difference in glucose uptake between LMTM monotherapy and add-on therapy is 2–3-fold greater in neocortical regions affected by neurofibrillary degeneration [ 6–8 ] than in cerebellum which is not affected [ 54 ].…”