IF an AAV9-delivered lysosomal targeting construct encoding a codon-optimized, engineered oxidative enzyme derived from soil actinomycete catabolism of bis-retinoid fluorophores (specifically A2E-class lipofuscin oxidases from Rhodococcus or Streptomyces spp., fused to a LAMP2a-derived lysosomal signal peptide and administered as a single intravenous injection at a dose of 2×10¹¹ vg/kg) is administered to aged (22–24-month-old), mixed-sex C57BL/6J mice with established post-mitotic lipofuscin burden,

THEN a ≥40% reduction in autofluorescent lipofuscin granule density in retinal pigment epithelium (RPE), dorsal root ganglia neurons, and cardiomyocytes, combined with a ≥30% improvement in autophagic flux (measured by LC3-II/LC3-I ratio and p62 clearance), and a ≥25% reduction in NF-κB-driven cytokines (IL-6, IL-1β, GDF15) in post-mitotic tissue lysates will be observed at 8 and 16 weeks post-injection, compared to AAV9-GFP vehicle controls,

BECAUSE the following causal chain holds:

1. Lipofuscin accumulates irreversibly in post-mitotic cells (RPE, cardiomyocytes, neurons) as a cross-linked fluorophore-protein-lipid polymer resistant to all endogenous mammalian lysosomal hydrolases, progressively congesting the lysosomal lumen and impairing autophagic clearance capacity — as described in the LysoSENS evidence summary in the Evidence Set, which identifies this undegradable intracellular waste as a primary driver of post-mitotic cellular dysfunction.

2. Lysosomal congestion by lipofuscin triggers lysosomal membrane permeabilization (LMP) and cathepsin leakage into the cytosol, activating the NLRP3 inflammasome and canonical NF-κB signaling, generating a SASP-equivalent inflammatory secretome from post-mitotic cells that are not themselves senescent — (senolytics and SASP modulators represent a therapeutic paradigm targeting a fundamental aging mechanism)[https://doi.org/10.1016/j.ebiom.2017.04.013]; this Evidence Set citation establishes the SASP-driven paracrine mechanism that the current hypothesis extends to non-dividing cells via a lysosomal route.

3. Certain actinomycete soil bacteria (e.g., Rhodococcus spp.) produce monooxygenases and dioxygenases capable of oxidatively cleaving polyene and bis-retinoid ring structures analogous to A2E under aerobic conditions — analogous to the cross-discipline search direction identifying extremophile and environmental remediation enzymes as unexploited tools for in vivo damage repair — [SPECULATIVE: direct enzymatic characterization of A2E-oxidase from actinomycetes in lysosomal pH conditions has not been published; this represents a key empirical gap].

4. Fusion of such an oxidase to a LAMP2a signal peptide enables chaperone-mediated lysosomal targeting, concentrating enzymatic activity precisely within the organelle where lipofuscin resides, thereby avoiding cytosolic off-target oxidative damage — [SPECULATIVE: LAMP2a-fusion strategy for exogenous oxidase delivery is unprecedented; precedent exi...

SENS category: GlycoSENS

Key references: • doi.org/10.1016/j.ebiom.2017.04.013]; • doi.org/10.1016/j.ebiom.2017.04.013]. • doi.org/10.1016/j.ebiom.2017.04.013