Hypothesis: Immune TFEB Reprogramming as a Primary Lever to Delay Systemic Aging

Core idea – Restoring TFEB activity specifically in hematopoietic cells will suppress inflammaging, improve organelle clearance, and extend healthspan without requiring broader systemic interventions.

Rationale

Aging is marked by a decline in autophagy gene expression (ATG5, ATG7, ATG12) driven by impaired TFEB nuclear translocation (1). This defect is especially pronounced in immune cells, where defective mitophagy fuels mitochondrial ROS, inflammasome activation, and a senescence‑associated secretory phenotype (SASP) rich in IL‑6 and IL‑1β (2). The resulting inflammaging propagates tissue damage, creating a vicious loop that accelerates functional decline across organs.

Evidence shows that macrophage‑specific TFEB overexpression attenuates atherosclerosis (3), while TFEB loss in kidney proximal tubules triggers systemic metabolic disturbance and amyloidosis (4). These tissue‑restricted manipulations demonstrate that immune TFEB can influence organism‑wide phenotypes, yet no study has tested whether immune‑centric TFEB rescue alone is sufficient to reverse global aging markers.

Novel mechanistic extension

Beyond autophagy, TFEB directly regulates the expression of immunoproteasome subunits (PSMB8, PSMB9, PSMB10) and lysosomal enzymes that process MHC‑I peptide loading. In senescent cells, compromised immunoproteasome activity leads to accumulation of misfolded proteins that stimulate cGAS‑STING signaling, amplifying type‑I interferon production and reinforcing SASP. By re‑activating TFEB in immune cells, we predict a coordinated boost in both autophagic flux and immunoproteasome‑mediated antigen processing, thereby reducing intracellular stress signals that drive SASP and breaking the inflammaging feedback loop.

Testable predictions

1. Cell‑autonomous rescue – Conditional TFEB overexpression in hematopoietic stem cells (Vav‑Cre;TFEB^OE) will increase LC3‑II turnover and mitochondrial clearance in macrophages and T cells isolated from aged mice (>20 mo).
2. SASP suppression – Serum IL‑6, IL‑1β, and IFN‑β levels will drop to young adult baseline in TFEB^OE mice, correlating with reduced p16^INK4a^ expression in peripheral tissues.
3. Healthspan extension – TFEB^OE mice will show improved grip strength, enhanced glucose tolerance, and delayed onset of frailty index scores compared with littermate controls, without changes in food intake or body weight.
4. Falsifiable outcome – If TFEB^OE fails to lower circulating SASP factors or improve functional assays despite verified autophagic restoration in immune cells, the hypothesis that immune TFEB is a primary driver of systemic aging is refuted.

Experimental approach

• Generate Vav‑Cre;TFEB^OE and control (Vav‑Cre;WT) cohorts.
• Confirm TFEB nuclear localization and target gene expression (ATG5, LAMP1, PSMB8) via immunoblot and qPCR in sorted CD11b^+ macrophages and CD8^+ T cells.
• Measure autophagic flux using mCherry‑GFP‑LC3 reporter in bone‑marrow derived macrophages.
• Quantify SASP cytokines in plasma via multiplex ELISA at 3, 6, 12 months.
• Assess frailty, grip strength, glucose tolerance, and survival.
• Include a rescue arm where TFEB^OE is combined with lysosomal inhibitor chloroquine to verify lysosomal dependence.

By isolating the immune compartment, this study directly tests whether re‑programming a single cell type can attenuate the core inflammatory circuitry that underlies aging. Positive results would shift therapeutic focus toward immune‑targeted autophagy enhancers as a proximate means to extend healthspan.