Sex‑Specific Cytokine Signaling Remodels the VPS34‑Beclin1 Autophagy Interactome During Aging

Hypothesis

Aging triggers a sex‑biased cytokine milieu that directly alters the composition of the VPS34‑Beclin1 autophagy complex, causing a preferential loss of specific interactors in females and driving tissue‑restricted proteostasis collapse.

Mechanistic Basis

• In aged female mice, circulating IL‑1β levels rise markedly (see sex‑specific immune activation).
• IL‑1β engages its receptor on neurons and microglia, activating IRAK4‑dependent kinases that phosphorylate Beclin1 at serine‑90/93.
• Phosphorylation reduces Beclin1’s affinity for VPS34 while increasing its binding to inhibitory Bcl‑2 family members, shifting the equilibrium toward a less active VPS34‑Beclin1 complex (proteostasis collapse via UPS/autophagy decline).
• Proximity‑labeling (e.g., TurboID) would capture this altered interactome, revealing loss of ATG14L and gain of Bcl‑2 in females, whereas males show a milder shift due to lower IL‑1β exposure.
• The resulting autophagy defect leads to accumulation of selective cargo such as IFB2 and EPS8 homologs, exacerbating neurodegeneration‑prone regions (spatial proteomics distinguishes healthy aging from AD).
• Because microglial IL‑1β production is estrogen‑responsive, the effect is amplified in females, linking hormonal state to interactome rewiring (extrinsic vs intrinsic drivers of PPI shifts).

Testable Predictions

1. Interactome shift – TurboID‑based VPS34 proximity labeling in hippocampal tissue from 24‑month‑old female mice will show a ≥30 % decrease in ATG14L peptide spectral matches and a ≥25 % increase in Bcl‑2 compared with age‑matched males (p < 0.01, n = 5 per sex).
2. Cytokine blockade – Chronic administration of an IL‑1 receptor antagonist (Anakinra) to aged females will restore the VPS34‑Beclin1 interactome to male‑like levels and reduce IFB2/EPS8 accumulation by ~40 % after 8 weeks, whereas males will show no significant change.
3. Functional outcome – Females treated with IL‑1RA will exhibit improved performance in the Morris water maze (escape latency ↓15 %) and extended median lifespan (~10 % increase) relative to vehicle‑treated females; male lifespan will be unchanged.
4. Sex‑hormone dependence – Ovariectomy of young females will blunt the age‑dependent IL‑1β rise and preserve the VPS34‑Beclin1 interactome, demonstrating estrogen’s role in amplifying the cytokine signal.

Falsifiability

If any of the following are observed, the hypothesis is refuted:

• No sex‑difference in VPS34‑Beclin1 interactome composition despite confirmed IL‑1β elevation.
• IL‑1RA fails to modify the interactome or autophagic flux in females.
• Alterations in the interactome do not correlate with changes in IFB2/EPS8 levels or cognitive performance.

These experiments use existing tools (TurboID, IL‑1RA, behavioral assays) and directly address the gap noted in aging interactome mapping—namely, the lack of tissue‑, sex‑, and cytokine‑resolved PPI dynamics (lack of large‑scale age‑resolved interactome studies; absence of proximity labeling in age‑specific interactomes).