Senolytic Therapies for Neurodegenerative Diseases

therapeutic

Senolytic Therapies for Neurodegenerative Diseases

Introduction

<table class=“infobox infobox-therapeutic”> <tr> <th class=“infobox-header” colspan=“2”>Senolytic Therapies for Neurodegenerative Diseases</th> </tr> <tr> <td class=“label”>Marker</td> <td>Detection</td> </tr> <tr> <td class=“label”>p16^INK4a</td> <td>IHC, qPCR</td> </tr> <tr> <td class=“label”>p21^CIP1</td> <td>IHC, Western</td> </tr> <tr> <td class=“label”>SA-β-gal</td> <td>Histochemistry</td> </tr> <tr> <td class=“label”>SASP factors</td> <td>ELISA, multiplex</td> </tr> <tr> <td class=“label”>Target</td> <td>Function</td> </tr> <tr> <td class=“label”>Bcl-2 family</td> <td>Anti-apoptotic</td> </tr> <tr> <td class=“label”>p53</td> <td>Apoptosis regulator</td> </tr> <tr> <td class=“label”>PI3K/Akt</td> <td>Survival pathway</td> </tr> <tr> <td class=“label”>HSP90</td> <td>Chaperone function</td> </tr> <tr> <td class=“label”>γ-secretase</td> <td>Notch signaling</td> </tr> <tr> <td class=“label”>Class</td> <td>Tyrosine kinase inhibitor</td> </tr> <tr> <td class=“label”>Primary target</td> <td>Bcr-Abl, Src</td> </tr> <tr> <td class=“label”>Senolytic target</td> <td>Bcl-2, Src</td> </tr> <tr> <td class=“label”>FDA status</td> <td>Approved (leukemia)</td> </tr> <tr> <td class=“label”>Drug</td> <td>Class</td> </tr> <tr> <td class=“label”>ABT-737</td> <td>Bcl-2 inhibitor</td> </tr> <tr> <td class=“label”>17-DMAG</td> <td>HSP90 inhibitor</td> </tr> <tr> <td class=“label”>Rapamycin</td> <td>mTOR inhibitor</td> </tr> <tr> <td class=“label”>Metformin</td> <td>AMPK activator</td> </tr> <tr> <td class=“label”>Trial</td> <td>Drug</td> </tr> <tr> <td class=“label”>NCT03415087</td> <td>D+Q</td> </tr> <tr> <td class=“label”>NCT0341504</td> <td>Fisetin</td> </tr> <tr> <td class=“label”>NCT04063124</td> <td>D+Q</td> </tr> <tr> <td class=“label”>Trial</td> <td>Drug</td> </tr> <tr> <td class=“label”>NCT04685590</td> <td>D+Q</td> </tr> <tr> <td class=“label”>NCT04446303</td> <td>Fisetin</td> </tr> <tr> <td class=“label”>Drug</td> <td>Common AEs</td> </tr> <tr> <td class=“label”>Dasatinib</td> <td>Fluid retention, rash</td> </tr> <tr> <td class=“label”>Quercetin</td> <td>Generally well-tolerated</td> </tr> <tr> <td class=“label”>Navitoclax</td> <td>Thrombocytopenia</td> </tr> <tr> <td class=“label”>Fisetin</td> <td>Well-tolerated</td> </tr> <tr> <td class=“label”>Component</td> <td>Target</td> </tr> <tr> <td class=“label”>Dasatinib</td> <td>BCR-ABL, BCL-2 family</td> </tr> <tr> <td class=“label”>Quercetin</td> <td>BCL-2 family, p53</td> </tr> <tr> <td class=“label”>Trial</td> <td>Compound</td> </tr> <tr> <td class=“label”>ALSENLITE</td> <td>D+Q</td> </tr> <tr> <td class=“label”>NCT04785300</td> <td>D+Q</td> </tr> <tr> <td class=“label”>Various</td> <td>Fisetin</td> </tr> <tr> <td class=“label”>Compound</td> <td>Common AEs</td> </tr> <tr> <td class=“label”>Dasatinib</td> <td>Fluid retention, cytopenia</td> </tr> <tr> <td class=“label”>Quercetin</td> <td>Generally well-tolerated</td> </tr> <tr> <td class=“label”>Fisetin</td> <td>GI symptoms</td> </tr> </table>

Senolytic Therapies For Neurodegenerative Diseases is a treatment approach for neurodegenerative diseases. This page provides comprehensive information about its mechanism of action, clinical evidence, and therapeutic potential.

Overview

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Senolytic drugs selectively eliminate senescent cells that accumulate with age and secrete pro-inflammatory “senescence-associated secretory phenotype” (SASP) factors[“@kirkland2024”]. These senescent cells contribute to chronic neuroinflammation and neuronal dysfunction in neurodegenerative diseases, making senolytics a promising therapeutic approach[“@yousefzadeh2023”]. [@yousefzadeh2023]

Cellular senescence is a state of irreversible cell cycle arrest characterized by the secretion of pro-inflammatory cytokines, chemokines, growth factors, and proteases collectively known as the SASP. In the brain, senescent neurons, astrocytes, and microglia accumulate with age and in neurodegenerative diseases, creating a toxic microenvironment that promotes disease progression. [@chang2024]

Molecular Mechanisms

Cellular Senescence in the Brain

Senescent cells in the brain exhibit distinct characteristics[@chang2024][@demaria2024]:

Senescence-Associated Secretory Phenotype (SASP)

The SASP includes: [@zhang2023]

  • Pro-inflammatory cytokines: IL-6, IL-8, IL-1β, TNF-α
  • Chemokines: CXCL1, CCL2, CCL5
  • Growth factors: VEGF, PDGF, TGF-β
  • Proteases: MMP-1, MMP-3, MMP-9
  • Other: ROS, ATP, microRNAs

Paracrine Senescence

A critical feature of senescent cells is their ability to induce senescence in neighboring cells through:

  1. SASP factor secretion
  2. Gap junction-mediated signaling
  3. Extracellular vesicle transfer
  4. ROS transfer

This creates a spread of senescence throughout tissues, amplifying the toxic microenvironment.

Senolytic Drug Targets

Therapeutic Candidates

Combination Senolytics

Dasatinib + Quercetin (D+Q)

The most extensively studied senolytic combination:

Clinical Trials:

  • NCT02848131: Safety in COPD (completed)
  • NCT03415087: AD trial (completed)
  • NCT04685590: Parkinson’s disease (ongoing)

Dosing: Dasatinib 100mg + Quercetin 1000mg, intermittent dosing

Fisetin + Dasatinib

An alternative combination being explored:

  • Fisetin: Natural senolytic flavonoid
  • Potentially better brain penetration than quercetin
  • Clinical trial in AD (NCT0341504)

Single-Agent Senolytics

Fisetin

A natural flavonoid with senolytic activity:

  • Mechanism: Multiple targets including PI3K/Akt, mTOR
  • Brain penetration: Better than quercetin
  • Dose: 20mg/kg in preclinical studies
  • Clinical trial: NCT0341504 in Alzheimer’s disease

Navitoclax (ABT-263)

Bcl-2 family inhibitor:

  • Mechanism: Inhibits Bcl-2, Bcl-xL, Bcl-w
  • Challenge: Thrombocytopenia due to platelet Bcl-xL
  • Solution: Intermittent dosing
  • Preclinical: Effective in PD models

Other Agents

Clinical Evidence

Alzheimer’s Disease

Biomarker Findings:

  • Reduced SASP factors in CSF
  • Decreased inflammatory markers
  • Improved cognitive scores (preliminary)

Parkinson’s Disease

Preclinical Evidence:

  • Reduced dopaminergic neuron loss in MPTP model
  • Improved motor function
  • Decreased α-synuclein aggregation

Safety Considerations

Adverse Effects

Mitigation Strategies

  1. Intermittent dosing: Reduces cumulative toxicity
  2. Targeted delivery: Nanoparticle formulations in development
  3. Combination with protectors: Bcl-2 family protectors

See Also

Background

The study of Senolytic Therapies For Neurodegenerative Diseases has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

External Links

Senolytic Mechanisms

Dasatinib + Quercetin (D+Q)

The D+Q combination is the most studied senolytic[@kirkland2024]:

Mechanism:

  • Inhibits anti-apoptotic BCL-2 family proteins
  • Induces apoptosis in senescent cells
  • Synergistic effect when combined

Fisetin

Fisetin is a natural senolytic[@yousefzadeh2023]:

  • Source: Strawberries, apples, grapes
  • Target: BCL-2 family, mTOR
  • Advantage: Better CNS penetration
  • Evidence: Strong pre-clinical data

Navitoclax (ABT-263)

BCL-2 family inhibitor[@chang2024]:

  • Target: BCL-2, BCL-xL, BCL-w
  • Challenge: Thrombocytopenia
  • Potential: Strong senolytic activity

Clinical Trial Status

Ongoing Trials

Clinical Results

  • D+Q: Safe in humans, senolytic activity confirmed
  • Fisetin: Phase 1 complete, proceeding to Phase 2
  • Navitoclax: Dose-limiting thrombocytopenia

Safety Profile

Adverse Effects

CNS Considerations

  • BBB penetration: Variable by compound
  • Off-target effects: Must assess
  • Dosing: Intermittent may be optimal