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Conserved Photoaging (UV-Induced Skin Damage) Module

Aging Module photoaging 0 disorders Pathograph 8
Conserved extrinsic skin-aging pathway by which chronic ultraviolet (chiefly UVB) exposure drives dermal matrix destruction and visible photoaging: UV irradiation and photo-oxidative injury (DNA damage, reactive oxygen species, ligand-independent growth-factor and cytokine-receptor activation) leads to MAP-kinase-driven activation of the AP-1 (c-Jun/c-Fos) and NF-kB transcription factors, which induce matrix metalloproteinases (collagenase MMP-1, stromelysin MMP-3, gelatinase MMP-9) and pro-inflammatory mediators (IL-1, IL-6, IL-8, COX-2/PTGS2), producing degradation of the dermal collagen and elastin extracellular matrix and, cumulatively, photoaging (wrinkling, laxity, solar elastosis). The deliberate extrinsic-aging complement of the intrinsic senescence and inflammaging modules.
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Pathophysiology Nodes

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5 shared nodes are defined in this module.
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Cell Types

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Keratinocyte CL:0000312 Cell Ontology (CL) Relation: this mechanism module involves this cell type This mechanism module involves Keratinocyte (CL:0000312). CL:0000312 is a cell type from the Cell Ontology. Dermal Fibroblast CL:0000057 Cell Ontology (CL) Relation: this mechanism module involves this cell type This mechanism module involves Dermal Fibroblast (CL:0000057). CL:0000057 is a cell type from the Cell Ontology.
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Biological Processes

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Response to UV GO:0009411 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves Response to UV (GO:0009411). GO:0009411 is a biological process from the Gene Ontology. Reactive Oxygen Species Generation GO:0072593 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased Reactive Oxygen Species Generation (GO:0072593). GO:0072593 is a biological process from the Gene Ontology. INCREASED Cellular Response to Oxidative Stress GO:0034599 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased Cellular Response to Oxidative Stress (GO:0034599). GO:0034599 is a biological process from the Gene Ontology. INCREASED MAPK Cascade GO:0000165 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased MAPK Cascade (GO:0000165). GO:0000165 is a biological process from the Gene Ontology. INCREASED NF-kappaB Signaling Activation GO:0043123 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased NF-kappaB Signaling Activation (GO:0043123). GO:0043123 is a biological process from the Gene Ontology. INCREASED Collagen Catabolic Process GO:0030574 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased Collagen Catabolic Process (GO:0030574). GO:0030574 is a biological process from the Gene Ontology. INCREASED Inflammatory Response GO:0006954 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased Inflammatory Response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. INCREASED Extracellular Matrix Disassembly GO:0022617 Gene Ontology (GO) Relation: this mechanism module involves this biological process This mechanism module involves increased Extracellular Matrix Disassembly (GO:0022617). GO:0022617 is a biological process from the Gene Ontology. INCREASED
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Notes

Conserved mechanism, one rate-limiting hub. The key conformance target is the central_effector node "MAPK Signaling and AP-1/NF-kB Transcriptional Activation": every route from a UV/oxidative insult to matrix destruction funnels through MAP-kinase-driven AP-1 (and NF-kB) transcriptional activation. Conforming entries substitute the tissue- and stimulus-specific detail while keeping this spine: the UV waveband and dose (UVB vs UVA vs solar-simulated), the dominant reactive species, the specific MMPs induced (MMP-1 collagenase, MMP-3 stromelysin, MMP-9 gelatinase), and the inflammatory mediators (IL-1, IL-6, CXCL8/IL-8, PTGS2/COX-2). Not modeled here and left to the conforming entry or a sibling module: UV mutagenesis and photocarcinogenesis (a distinct DNA-damage/oncogenesis output), melanogenesis and dyspigmentation, and the intrinsic (chronological) aging arm, which converges on the same AP-1/MMP effector but is driven by senescence and inflammaging rather than UV (see the cellular_senescence and inflammaging modules). Chemistry (ROS, retinoids) is described in prose per module convention; a treatment therapeutic_agent carries the CHEBI id. Not an Xogenesis module: the terminal output is destruction and disorganization of a normal matrix, not formation of a discrete pathological structure (actinic/solar elastosis, an accumulation of abnormal elastotic material, is the closest structural correlate and is described in prose at the consequence node rather than anchored as Xogenesis).
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Experimental Models / Non-animal Systems

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Outer Biosciences long-term ex vivo human skin platform (UVB photodamage arm) PRIMARY CELL CULTURE
An ex vivo human skin platform used to model UVB photodamage and topical photoprotection within preserved tissue architecture. UVB (300 mJ/cm2) induced epidermal and dermal pathology (parakeratosis, dyskeratosis, collagen bundle fragmentation), raised lactate dehydrogenase release and IL-8 secretion, and activated inflammatory, stress, and remodeling programs (TNF-alpha/NF-kB, UV response, IL6/JAK/STAT3) with induction of IL1A, IL1B, CXCL8, PTGS2, and MMP1. Topically applied sunscreen substantially mitigated these responses.
Models: UVB Irradiation and Photo-oxidative Injury (partially recapitulates), MMP Upregulation and Inflammatory Mediator Induction (partially recapitulates), UVB Irradiation and Photo-oxidative Injury (rescues)
DOI:10.64898/2026.04.30.721933 Preprint · not peer-reviewed
Source is a bioRxiv preprint (DOI:10.64898/2026.04.30.721933), not yet peer-reviewed. Evidence snippets quote the cached abstract; figure-level detail is summarized in prose.
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Used By Disorder Entries

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No disorder entries currently reference this module via conforms_to.
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence-backed metadata.
Pathograph: causal mechanism network for Conserved Photoaging (UV-Induced Skin Damage) Module Interactive directed graph showing how this shared module's pathophysiology nodes connect.
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Pathophysiology

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UVB Irradiation and Photo-oxidative Injury
trigger
Ultraviolet irradiation (chiefly UVB) absorbed by skin chromophores inflicts direct DNA photodamage and generates reactive oxygen species, and acts as a broad ligand-independent activator of keratinocyte and dermal-cell growth-factor and cytokine receptors. This photo-oxidative injury is the initiating insult of extrinsic skin aging.
Keratinocyte CL:0000312 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves Keratinocyte (CL:0000312). CL:0000312 is a cell type from the Cell Ontology. Dermal Fibroblast CL:0000057 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves Dermal Fibroblast, annotated with fibroblast (CL:0000057). CL:0000057 is a cell type from the Cell Ontology.
Response to UV GO:0009411 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves Response to UV (GO:0009411). GO:0009411 is a biological process from the Gene Ontology. Reactive Oxygen Species Generation GO:0072593 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Reactive Oxygen Species Generation, annotated with reactive oxygen species metabolic process (GO:0072593). GO:0072593 is a biological process from the Gene Ontology. INCREASED Cellular Response to Oxidative Stress GO:0034599 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Cellular Response to Oxidative Stress (GO:0034599). GO:0034599 is a biological process from the Gene Ontology. INCREASED
Downstream
  • MAPK Signaling and AP-1/NF-kB Transcriptional Activation Photo-oxidative injury and receptor activation transduce into MAP-kinase signaling that activates the AP-1 and NF-kB transcription factors.
MAPK Signaling and AP-1/NF-kB Transcriptional Activation
central effector
UV-activated cell-surface receptors and reactive oxygen species drive MAP-kinase cascades (p38, ERK, JNK) that converge on the nucleus to induce c-Jun, which heterodimerizes with c-Fos to form the AP-1 transcription factor, and to activate NF-kB. This transcriptional hub is the disorder-agnostic, rate-limiting step that couples the UV/oxidative insult to matrix-degrading and inflammatory gene expression.
MAPK Cascade GO:0000165 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased MAPK Cascade (GO:0000165). GO:0000165 is a biological process from the Gene Ontology. INCREASED NF-kappaB Signaling Activation GO:0043123 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased NF-kappaB Signaling Activation, annotated with positive regulation of canonical NF-kappaB signal transduction (GO:0043123). GO:0043123 is a biological process from the Gene Ontology. INCREASED
Downstream
  • MMP Upregulation and Inflammatory Mediator Induction AP-1 and NF-kB induce transcription of matrix metalloproteinases and pro-inflammatory mediators.
MMP Upregulation and Inflammatory Mediator Induction
effector
Activated AP-1 and NF-kB induce the matrix metalloproteinases (collagenase MMP-1, stromelysin MMP-3, 92 kDa gelatinase MMP-9) and pro-inflammatory mediators (IL-1, IL-6, CXCL8/IL-8, COX-2/PTGS2), the effectors that dismantle the dermal matrix and sustain a low-grade inflammatory microenvironment.
Dermal Fibroblast CL:0000057 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves Dermal Fibroblast, annotated with fibroblast (CL:0000057). CL:0000057 is a cell type from the Cell Ontology.
Collagen Catabolic Process GO:0030574 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Collagen Catabolic Process (GO:0030574). GO:0030574 is a biological process from the Gene Ontology. INCREASED Inflammatory Response GO:0006954 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Inflammatory Response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology. INCREASED
Downstream
  • Dermal ECM (Collagen and Elastin) Degradation MMP activity degrades the collagen and elastin of the dermal extracellular matrix.
Dermal ECM (Collagen and Elastin) Degradation
effector
MMP-mediated proteolysis, together with reduced procollagen synthesis (compounded by UV inhibition of TGF-beta signaling), fragments and depletes the dermal collagen and elastin extracellular matrix. Repeated cycles of degradation and imperfect repair accumulate as disorganized matrix, including the abnormal elastotic material of solar (actinic) elastosis.
Extracellular Matrix Disassembly GO:0022617 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Extracellular Matrix Disassembly (GO:0022617). GO:0022617 is a biological process from the Gene Ontology. INCREASED Collagen Catabolic Process GO:0030574 Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased Collagen Catabolic Process (GO:0030574). GO:0030574 is a biological process from the Gene Ontology. INCREASED
Downstream
  • Photoaging Cumulative dermal matrix loss and disorganization manifests as clinical photoaging.
Photoaging
consequence
The cumulative clinical outcome: wrinkling, laxity, roughness, dyspigmentation, and solar elastosis of chronically sun-exposed skin. Photoaging is a cumulative process whose severity tracks lifetime UV dose and skin pigmentation, distinct from the passage-of-time-dependent intrinsic aging with which it shares the downstream AP-1/MMP effector.