IF selnoflast (IZD334; oral NLRP3 ATPase inhibitor, Phase 2 clinical candidate) is administered at a dose extrapolated from human Phase 2 pharmacokinetics (~100 mg/kg/day oral gavage, bridging from published murine MCC950 equivalence) to aged (20–22 month), male and female C57BL/6J mice carrying an established TET2-heterozygous CHIP clone generated by competitive bone marrow transplantation (50:50 TET2+/− : wild-type donor HSCs into lethally irradiated aged recipients, allowed 16 weeks engraftment prior to treatment), with a parallel PAI-1 neutralizing antibody co-arm (tiplaxtinin/PAI-039 or anti-PAI-1 monoclonal, i.p., 3×/week),

THEN the variant allele frequency (VAF) of the TET2-mutant clone — measured serially by droplet digital PCR (ddPCR) of peripheral blood and confirmed at sacrifice by scRNA-seq clonotype tracking — will decline by ≥25% relative to vehicle-treated aged CHIP controls by week 12 of treatment, with a corresponding normalization of bone marrow interstitial IL-1β and IL-6 concentrations (Luminex, ≥40% reduction), reduction of PAI-1 (SERPINE1) protein in bone marrow stromal cells (IHC/ELISA), and partial re-establishment of WT-clone competitive parity (TET2+/− : WT ratio shifting toward 1:1 from a treatment-start ratio of ≥2:1),

BECAUSE the following causal chain connects selnoflast + PAI-1 co-blockade to OncoSENS-aligned fitness equalization:

1. TET2-LOF derestricts NLRP3 transcription in myeloid-lineage cells: TET2 normally hydroxymethylates and silences the NLRP3 locus; loss-of-function removes this epigenetic brake, causing constitutive low-level NLRP3 priming that renders TET2-mutant monocytes/macrophages hypersensitive to secondary DAMPs — this epigenetic access mechanism is directly analogous to TET2's restriction of chromatin access demonstrated for other loci (ZNF397/TET2 chromatin access restriction)[https://doi.org/10.1101/2023.10.24.563645].

2. Activated NLRP3 drives an IL-1β/IL-6 autocrine-paracrine loop that is fitness-conferring: In the aged bone marrow niche, where baseline inflammaging is already elevated, this loop selectively amplifies survival and self-renewal signaling (NF-κB, STAT3) in TET2-mutant HSCs but not WT HSCs, because WT HSCs retain TET2-mediated suppression of the same pathway; canonical NLRP3 inflammasome activation is established as the molecular driver linking systemic low-grade inflammation to tissue functional decline with aging (NLRP3 inflammasome links systemic low-grade inflammation to functional decline in aging)[https://doi.org/10.1016/j.cmet.2013.09.010].

3. PAI-1 secreted by aged bone marrow senescent stromal cells acts as a paracrine NLRP3 co-primer [SPECULATIVE — novel mechanistic link]: PAI-1 (SERPINE1), a canonical SASP component elevated in aged tissues, binds LRP1 on myeloid cells and activates downstream ROS and potassium efflux — two established NLRP3 Signal 2 triggers — thereby selectively amplifying NLRP3 assembly in the already-primed TET2-mutant myeloid com...

SENS category: OncoSENS

Key references: • doi.org/10.1101/2023.10.24.563645]. • doi.org/10.1016/j.cmet.2013.09.010]. • doi.org/10.1101/2025.01.14.25320566] • doi.org/10.1101/2023.10.24.563645]; • doi.org/10.1016/j.cmet.2013.09.010];