Hypothesis Comparison

graph TD
    A["Cellular Stress
DNA Damage
Oxidative Stress"] -->|"triggers"| B["Microglial Senescence
p16INK4A and p21CIP1
Expression"]
    B -->|"activates"| C["NF-kappaB and C/EBPbeta
Transcriptional
Reprogramming"]
    C -->|"upregulates"| D["SASP Cytokine
Production
IL-1beta, TNF-alpha, IL-6"]
    C -->|"increases expression"| E["MMP2 Gelatinase A
72 kDa
5-8 fold upregulation"]
    C -->|"increases expression"| F["MMP9 Gelatinase B
92 kDa
5-8 fold upregulation"]
    G["Perineuronal Nets
Aggrecan, Versican
Neurocan, Brevican"] -->|"substrate for"| E
    G -->|"substrate for"| F
    E -->|"cleaves Glu-Leu bonds"| H["Aggrecan and
Brevican Degradation
Zinc-dependent catalysis"]
    F -->|"cleaves linkages"| I["Versican and
Tenascin-R Degradation
pH 7.4 optimal activity"]
    H -->|"disrupts"| J["PNN Structural
Integrity Loss
Microdomains compromised"]
    I -->|"disrupts"| J
    J -->|"alters"| K["Acetylcholine Receptor
Spacing and Distribution
Nicotinic and Muscarinic"]
    K -->|"impairs"| L["Cholinergic Synaptic
Transmission
Reduced ACh signaling"]
    D -->|"promotes"| M["Chronic Neuroinflammation
Sustained SASP
Feedback amplification"]
    M -->|"enhances"| E
    M -->|"enhances"| F
    L -->|"leads to"| N["Cholinergic Neuron
Dysfunction
Synaptic plasticity loss"]
    N -->|"contributes to"| O["Cognitive Decline
Memory Impairment
Learning deficits"]
    P["Chondroitin Sulfate
Proteoglycans
CSPGs"] -->|"components of"| G
    Q["Hyaluronic Acid and
Tenascin-R
Interconnecting matrix"] -->|"stabilizes"| G
    R["MMP2/MMP9 Inhibitors
Therapeutic targets
Doxycycline, Marimastat"] -->|"blocks"| E
    R -->|"blocks"| F

    classDef normal fill:#4fc3f7,stroke:#2196f3
    classDef therapeutic fill:#81c784,stroke:#4caf50
    classDef pathology fill:#ef5350,stroke:#f44336
    classDef outcome fill:#ffd54f,stroke:#ff9800
    classDef molecular fill:#ce93d8,stroke:#9c27b0

    class A,P,Q normal
    class R therapeutic
    class B,C,D,E,F,H,I,M pathology
    class L,N,O outcome
    class G,J,K molecular

graph TD
    A["Cellular Senescence
Astrocytes and Microglia"] -->|"Triggers"| B["SASP Activation
Senescence-Associated
Secretory Phenotype"]
    B -->|"Secretes"| C["Pro-inflammatory
Cytokines
IL-1beta, TNF-alpha, IL-6"]
    B -->|"Releases"| D["Complement Initiators
C1q, C3, C4"]
    B -->|"Produces"| E["Chemokines and
Matrix Proteases
CCL2, MMP3"]
    
    D -->|"Activates"| F["Classical Complement
Pathway Initiation
C1q-C1r-C1s Complex"]
    F -->|"Cleaves"| G["C4 and C2
Formation of
C3 Convertase C4b2a"]
    G -->|"Amplifies"| H["C3 Cleavage
C3a and C3b
Generation"]
    
    H -->|"Forms"| I["C5 Convertase
C4b2a3b Complex
Alternative Pathway Feed-in"]
    I -->|"Generates"| J["C5a Anaphylatoxin
Microglial
Chemotaxis Signal"]
    I -->|"Initiates"| K["Terminal Pathway
C5b-9 Membrane
Attack Complex"]
    
    H -->|"Opsonizes"| L["Synaptic Tagging
C3b Deposition on
Neuronal Synapses"]
    L -->|"Recognized by"| M["Microglial CR3
Complement Receptor 3
CD11b-CD18"]
    M -->|"Triggers"| N["Complement-Mediated
Synaptic Pruning
Phagocytosis"]
    
    J -->|"Activates"| O["Microglial Migration
and Activation
M1 Polarization"]
    O -->|"Enhances"| N
    C -->|"Amplifies"| O
    
    N -->|"Results in"| P["Progressive Synapse Loss
Before Plaque Formation
Early AD Pathology"]
    P -->|"Leads to"| Q["Cognitive Decline
Memory Impairment
Neurodegeneration"]
    
    R["Therapeutic C1q-C3
Inhibition in SASP
Microenvironments"] -->|"Blocks"| D
    R -->|"Prevents"| F
    
    classDef normal fill:#4fc3f7,stroke:#2196f3
    classDef therapeutic fill:#81c784,stroke:#4caf50
    classDef pathology fill:#ef5350,stroke:#f44336
    classDef outcome fill:#ffd54f,stroke:#ff9800
    classDef molecular fill:#ce93d8,stroke:#9c27b0
    
    class A,B,C,D,E normal
    class F,G,H,I,J,K,L,M molecular
    class N,O,P pathology
    class Q outcome
    class R therapeutic