Redox‑responsive protein nanoparticles that co‑deliver resveratrol and quercetin convert transient hepatic ROS into SIRT1‑driven signal, enhancing mitochondrial health while lowering oxidative damage

Hypothesis

Protein‑nanoparticle‑mediated, redox‑responsive co‑delivery of resveratrol and quercetin can shift hepatic SIRT1 activation from noise‑driven to signal‑driven ROS, thereby increasing deacetylation of PGC‑1α and SIRT3 while lowering biomarkers of oxidative damage.

Mechanistic rationale

• Resveratrol’s rapid glucuronidation/sulfation limits nuclear access [1]. Encapsulation in BSA‑based nanoparticles protects the polyphenol and raises hepatic exposure 2‑3‑fold.
• Quercetin covalently linked to the nanoparticle surface via a cleavable disulfide bond inhibits hepatic sulfotransferases locally, extending resveratrol’s half‑life [1].
• Incorporation of a H₂O₂‑sensitive thioketal linker in the nanoparticle matrix triggers release only when intracellular H₂O₂ exceeds a threshold associated with transient, signaling ROS (e.g., exercise‑induced bursts) but remains inert under basal or sustained oxidative stress.
• This creates a feedback loop: modest ROS spikes → nanoparticle disassembly → localized resveratrol/quercetin release → SIRT1 activation → PGC‑1α deacetylation → mitochondrial biogenesis → improved redox handling, which then quenches excess ROS, preventing noise accumulation.
• Simultaneous activation of SIRT3 via NAD⁺ rise (from SIRT1‑driven NAMPT upregulation) further accelerates ROS detoxification, providing isoform‑specific redox tuning.

Testable predictions

1. In a double‑blind, crossover trial (n=30 healthy volunteers), oral administration of the formulated nanoparticle will increase hepatic nuclear SIRT1 activity (measured by peripheral blood mononuclear cell PGC‑1α deacetylation) by ≥40 % compared with standard resveratrol capsule, while quercetin alone shows no change.
2. Plasma 8‑iso‑PGF₂α (a marker of lipid peroxidation) will decrease by ≥25 % after 4 weeks of nanoparticle treatment, whereas malondialdehyde levels will remain unchanged in the control arm.
3. Using a ROS‑sensitive fluorescent probe (e.g., HyPer) in isolated hepatocytes, nanoparticle exposure will produce a transient HyPer signal that correlates with SIRT1 activation, whereas sustained H₂O₂ treatment will not trigger release or SIRT1 deacetylation.
4. Blocking SIRT1 with EX‑527 will abolish the nanoparticle‑induced increase in SIRT3 activity and the associated rise in mitochondrial membrane potential (JC‑1 ratio), confirming the upstream role of SIRT1.

Falsifiability

If the nanoparticle formulation fails to produce a significant increase in PGC‑1α deacetylation or does not lower oxidative‑damage biomarkers relative to placebo, the hypothesis that redox‑responsive delivery converts noise ROS into signal ROS via SIRT1 activation is refuted.