1. Causal aging node
Name the failure mode before naming a peptide.
metabolic overload, sarcopenia, senescent-cell burden, NAD decline, epigenetic drift
← Discovery
Discovery story
Modality fit — causal-node and receptor-gate routing.
The longevity modality workbench shows how DiscoveryLab routes a hypothesis to the right modality through causal nodes and receptor gates.
New workbench gate
Match the aging node to the right modality before generating peptides.
The longevity workbench now treats peptide design as a modality decision, not a default. Each target is routed through causal-node, location, receptor-role, and engineering gates before candidate generation.
Targets assessed
6
six canonical longevity mechanisms
Peptide-first
3
GLP-1R, ACVR2B, FGF21/KLB
Delivery-only
1
senescence surface markers
Wrong modality
2
NAD salvage, OSK reprogramming
2. Location
Classify the node as extracellular, intracellular, or mixed.
surface GPCRs and secreted ligands are peptide-addressable; nuclear factors are not
3. Receptor role
Separate receptor pharmacology from delivery zip codes.
GLP-1R agonism is mechanism; uPAR binding is only targeting for a payload
4. Engineering burden
Route to the modality that can survive human PK, safety, and endpoint tests.
half-life extension, protease resistance, biased signaling, conjugate linkers, or gene control
practical decision tree
No extracellular causal node
route to small molecule, precursor, gene therapy, or mRNA
Extracellular but receptor is only a zip code
route to conjugate, ADC, CAR, or nanoparticle delivery
Extracellular receptor is mechanism
allow peptide agonist/antagonist or protein-biologic design
Engineering gates fail
hold candidate before generation or wet-lab handoff
GLP1R · Incretin axis
GLP-1R / GIPR / glucagon-family receptors
causal node
Deregulated nutrient sensing, visceral adiposity, chronic inflammation, and cardiometabolic organ stress.
extracellular?
Yes. GLP-1R-family receptors are extracellular ligand-binding GPCRs.
receptor role
Yes. Agonism is the validated intervention point, not just a targeting label.
preferred modality
Engineered peptide agonist or multi-agonist
engineering required
Protease resistance against DPP-4-like cleavageHalf-life extension by albumin binding, Fc/protein fusion, depot, or acylationBiased signaling and internalization tuningCNS/organ targeting rationale when extending to neuroprotection or cardioprotectionFrailty-sparing profile: lean mass, nutrition, and older-adult tolerability gates
workbench action
Adopt as the positive-control peptide-first receptor program for longevity-facing discovery.
claim boundary
Cardiometabolic healthspan-adjacent; do not claim generalized longevity without endpoint evidence.
ACVR2B · TGF-beta superfamily
Myostatin / activin / ActRIIA/IIB axis
causal node
Sarcopenia, frailty, impaired recovery, and lean-mass loss during weight reduction.
extracellular?
Yes. Myostatin, activins, and related ligands bind extracellular ActRII receptors.
receptor role
Partially. Blocking the axis is plausible, but muscle function matters more than mass alone.
preferred modality
Antibody, ligand trap, peptibody, Fc-fusion, or selective antagonist
engineering required
Selectivity over BMP and repair/tissue-maintenance signalingFunction-first endpoints: strength, gait, recovery, falls riskBiologic formulation and skeletal-muscle exposureLigand-trap breadth risk: vascular/telangiectasia and off-target ligand capture reviewIP/freedom-to-operate review around antibodies, bimagrumab-like agents, and ActRIIB trapsCombination review with incretin-induced weight loss
workbench action
Adopt as a biologic/peptibody branch, not as a raw short-peptide stack.
claim boundary
Anti-frailty hypothesis; not a proven lifespan intervention.
SENESCENCE_SURFACE · Targeted senolysis
uPAR / DPP4 / CD9 / integrin-style senescent-cell markers
causal node
Senescent-cell accumulation and SASP-driven inflammatory tissue dysfunction.
extracellular?
Partially. Some markers are extracellular, but the lethal mechanism must reach intracellular survival machinery.
receptor role
No. The surface marker is a zip code for delivery, not the therapeutic mechanism.
preferred modality
Peptide-drug conjugate, ADC, bispecific, CAR-T/CAR-NK, or nanoparticle
engineering required
Single-cell/proteomic surface-marker validation across aged tissuesCleavable linker and payload release designRepair-cell sparing and wound-healing safety gatesHumanization/de-immunization and off-target immune activation screensDelivery-system choice: PDC, ADC, CAR, nanoparticle, or exosome-mimetic route
workbench action
Adopt as a delivery-track workflow with payload/linker scoring and tissue-specific validation.
claim boundary
Targeted clearance concept; receptor binding alone is not a senolytic mechanism.
FGF21_KLB_FGFR1C · Fasting-hormone metabolic axis
FGF21 / beta-Klotho / FGFR1c
causal node
Loss of metabolic flexibility, hepatic steatosis, insulin resistance, and dyslipidemia.
extracellular?
Yes. FGF21 is secreted and requires beta-Klotho/FGFR receptor complexes.
receptor role
Yes, but complex. Agonism can mimic part of fasting adaptation while risking off-target FGFR biology.
preferred modality
Long-acting protein analog, Fc-fusion, peptibody, or agonist antibody
engineering required
PEG/Fc/albumin or analog stability for practical dosingKLB-dependent FGFR1c selectivityLiver/adipose metabolic tissue targetingBone, appetite, growth-axis, and durability safety trackingPractical formulation gate: weekly subcutaneous, PEG/Fc, albumin, or depot format
workbench action
Adopt as a metabolic protein-engineering program with liver-fat and insulin-sensitivity endpoints.
claim boundary
Metabolic disease/fasting-mimic hypothesis; longevity translation remains speculative.
NAD_SALVAGE · Intracellular metabolism
NRK1 / NMNAT / CD38 / NAD+ salvage
causal node
NAD+ decline, impaired DNA repair, mitochondrial dysfunction, and inflammatory NAD consumption.
extracellular?
No. The key nodes are intracellular enzymes, consumers, and substrates.
receptor role
No. There is no clean surface receptor to agonize or antagonize.
preferred modality
Metabolic precursor, prodrug, small molecule, or gene/mRNA strategy
engineering required
Precursor/prodrug delivery instead of receptor peptide designCD38/PARP/sirtuin context only with tissue-specific evidenceFunctional rescue endpoints beyond NAD-level movementExplicit no-peptide-generation decision record unless peptide is only a carrier
workbench action
Block peptide-first generation and route to non-peptide modality planning.
claim boundary
Modality mismatch for peptide design.
OSK_REPROGRAMMING · Epigenetic reprogramming
OCT4 / SOX2 / KLF4 partial reprogramming
causal node
Epigenetic drift, loss of transcriptional fidelity, and cellular identity erosion.
extracellular?
No. OSK factors are nuclear transcriptional regulators.
receptor role
No. The problem is regulated intracellular expression, not receptor pharmacology.
preferred modality
AAV, LNP, mRNA, regulated expression, or synthetic-biology control system
engineering required
Temporal control to avoid dedifferentiationTissue-specific promoters or delivery restrictionTumor-safety, pluripotency, and cell-identity hard gatesPeptides only as optional carriers, not as the therapeutic mechanismManufacturing and release controls for GMP vector/mRNA/protein material
workbench action
Block receptor-first peptide generation and route to gene/mRNA planning.
claim boundary
Gene/mRNA/synthetic-biology program, not a peptide pharmacology program.
More on discovery
Related on this track
Problem
Why brute-force peptide search fails.
Hair-loss program
Local follicle-regeneration workbench.
CNS pack
Small-molecule CNS translational evidence layer.
Microbiome
Ecosystem programming and microbial indirection.
MOTS-c candidate
Evidence-backed seed framing.
Natural seeds
Parent peptide library and guardrails.
Search space
Eight-stage reduction strategy.
← Back to Discovery index
All sections on the discovery track.