IF a macrocyclic peptidomimetic (provisionally designated hClpP-HRA-1) incorporating a constrained bicyclic scaffold bearing a guanidinium-carboxylate salt-bridge mimetic pharmacophore targeting the handle region allosteric pocket at the A192/E196 interface of human mitochondrial ClpP (PDB: 9DKV), synthesized via Fmoc-SPPS with on-resin head-to-tail cyclization incorporating non-natural amino acids (β-methyl ornithine at position corresponding to R196 mimic; γ-carboxyglutamate at position corresponding to E192 mimic) and conjugated to a mitochondria-targeting triphenylphosphonium (TPP) moiety, is administered at 100–300 nM (in vitro) or 10–30 mg/kg/day oral gavage (in vivo) to aged (24-month) C57BL/6J female mice or primary human fibroblasts derived from donors >70 years,

THEN a measurable and statistically significant enhancement of mitochondrial ClpP-dependent proteolytic activity (EC50 in the 50–500 nM range in fluorogenic casein degradation assays; ≥2-fold increase over vehicle in aged cells vs. <1.2-fold in young cells), a reduction of accumulated damaged and oxidatively modified mitochondrial proteins (≥30% reduction in carbonylated mitochondrial proteome by oxyblot/pulse-chase TMT proteomics), improved mitochondrial membrane potential (ΔΨm, JC-1 fluorescence ratio), and enhanced cellular ATP production (Seahorse XF), will be observed with >50-fold selectivity over bacterial ClpP orthologs, proteasome 20S, and calpains,

BECAUSE the following causal chain:

1. Aged mitochondria accumulate unfolded, oxidized, and aggregated proteins that cannot be cleared by existing ClpP activity because the aging proteome progressively shifts human mitochondrial ClpP toward the compressed/inactive conformation, reducing the intrinsic turnover capacity needed to clear the substrate backlog — this is an accumulated damage state that only direct activation of the degradation machinery can reverse (Research Context, Literature Task Output — hClpP conformational dynamics section).

2. The A192/E196 interface constitutes a conformational switch: The A192E/E196R gain-of-function mutation in human mitochondrial ClpP has been established to constitutively stabilize the active extended conformation, demonstrating that this salt bridge is the key allosteric latch governing the compressed-to-extended transition (Research Context — novel aspect statement). hClpP-HRA-1 mimics precisely this salt bridge geometry rather than simply occupying the active site or displacing ClpX, providing constitutive low-level activation rather than dysregulated hyper-activation.

3. Macrocyclic constraint reduces conformational entropy of the peptidomimetic, locking the guanidinium-carboxylate pharmacophore in the precise spatial geometry required to simultaneously engage A192 (hydrophobic handle helix contact) and E196 (electrostatic anchor) within the handle region pocket, achieving sub-100 nM Kd via SPR — a binding affinity enabled by the preorganized scaffold that lin...

SENS category: LysoSENS