ICAM1 - Intercellular Adhesion Molecule 1
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">icam1</th>
</tr>
<tr>
<td class="label">
Gene Symbol</td>
<td>ICAM1</td>
</tr>
<tr>
<td class="label">
Official Name</td>
<td>Intercellular Adhesion Molecule 1</td>
</tr>
<tr>
<td class="label">
Chromosomal Location</td>
<td>19p13.2</td>
</tr>
<tr>
<td class="label">
Gene ID</td>
<td>3383</td>
</tr>
<tr>
<td class="label">
NCBI Reference</td>
<td>NM_000201</td>
</tr>
<tr>
<td class="label">
UniProt</td>
<td>P05362</td>
</tr>
<tr>
<td class="label">
Ensembl</td>
<td>ENSG00000090339</td>
</tr>
<tr>
<td class="label">Integrin</td>
<td>Alternative Name</td>
</tr>
<tr>
<td class="label">
ITGAL/CD11a</td>
<td>LFA-1</td>
</tr>
<tr>
<td class="label">
ITGAM/CD11b</td>
<td>Mac-1</td>
</tr>
<tr>
<td class="label">
ITGAX/CD11c</td>
<td>αXβ2</td>
</tr>
<tr>
<td class="label">
ITGAM/CD11d</td>
<td>αDβ2</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">
Blocking Antibodies</td>
<td>Anti-ICAM1 monoclonal antibodies</td>
</tr>
<tr>
<td class="label">
Small Molecule Inhibitors</td>
<td>ICAM1-LFA-1 interaction blockers</td>
</tr>
<tr>
<td class="label">
Gene Therapy</td>
<td>siRNA/shRNA silencing</td>
</tr>
<tr>
<td class="label">
Soluble Receptors</td>
<td>ICAM1-Fc fusion pr
...ICAM1 - Intercellular Adhesion Molecule 1
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">icam1</th>
</tr>
<tr>
<td class="label">
Gene Symbol</td>
<td>ICAM1</td>
</tr>
<tr>
<td class="label">
Official Name</td>
<td>Intercellular Adhesion Molecule 1</td>
</tr>
<tr>
<td class="label">
Chromosomal Location</td>
<td>19p13.2</td>
</tr>
<tr>
<td class="label">
Gene ID</td>
<td>3383</td>
</tr>
<tr>
<td class="label">
NCBI Reference</td>
<td>NM_000201</td>
</tr>
<tr>
<td class="label">
UniProt</td>
<td>P05362</td>
</tr>
<tr>
<td class="label">
Ensembl</td>
<td>ENSG00000090339</td>
</tr>
<tr>
<td class="label">Integrin</td>
<td>Alternative Name</td>
</tr>
<tr>
<td class="label">
ITGAL/CD11a</td>
<td>LFA-1</td>
</tr>
<tr>
<td class="label">
ITGAM/CD11b</td>
<td>Mac-1</td>
</tr>
<tr>
<td class="label">
ITGAX/CD11c</td>
<td>αXβ2</td>
</tr>
<tr>
<td class="label">
ITGAM/CD11d</td>
<td>αDβ2</td>
</tr>
<tr>
<td class="label">Strategy</td>
<td>Approach</td>
</tr>
<tr>
<td class="label">
Blocking Antibodies</td>
<td>Anti-ICAM1 monoclonal antibodies</td>
</tr>
<tr>
<td class="label">
Small Molecule Inhibitors</td>
<td>ICAM1-LFA-1 interaction blockers</td>
</tr>
<tr>
<td class="label">
Gene Therapy</td>
<td>siRNA/shRNA silencing</td>
</tr>
<tr>
<td class="label">
Soluble Receptors</td>
<td>ICAM1-Fc fusion proteins</td>
</tr>
<tr>
<td class="label">
Natural Compounds</td>
<td>Curcumin, resveratrol</td>
</tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">ALS</a>, <a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/alzheimer" style="color:#ef9a9a">Alzheimer</a>, <a href="/wiki/anxiety" style="color:#ef9a9a">Anxiety</a>, <a href="/wiki/atherosclerosis" style="color:#ef9a9a">Atherosclerosis</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">256 edges</a></td>
</tr>
</table>
Pathway Diagram
Mermaid diagram (expand to render)
Introduction
Icam1 Intercellular Adhesion Molecule 1 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Intercellular Adhesion Molecule 1 (ICAM1) encodes a cell surface glycoprotein that plays critical roles in immune cell adhesion, leukocyte trafficking, and neuroinflammation. It is a key mediator of the inflammatory response in neurodegenerative diseases. ICAM1 is expressed on endothelial cells, epithelial cells, fibroblasts, and immune cells, and its expression is dramatically upregulated by proinflammatory cytokines[@dustin1986].
Protein Structure
ICAM1 is a type I transmembrane glycoprotein with the following domains[@springer1994]:
- Signal peptide (1-23 aa): Directs protein to secretory pathway
- Extracellular domain (24-453 aa): Contains 5 immunoglobulin-like domains (Ig-like)
- Transmembrane domain (454-477 aa): Single pass alpha-helix
- Cytoplasmic tail (478-532 aa): Contains serine and threonine residues for phosphorylation
The protein can be alternatively spliced to produce multiple isoforms, including a soluble form (sICAM1) lacking the transmembrane domain[^3].
Ig-like Domains
Each of the five Ig-like domains contains conserved cysteine residues forming disulfide bonds that stabilize the protein's three-dimensional structure. The N-terminal domain (D1) contains the binding site for leukocyte integrins LFA-1 and Mac-1[@shimaoka2003].
Molecular Function
ICAM1 functions as a ligand for leukocyte integrins[@hynes1992]:
The ICAM1-LFA-1 interaction is critical for immune synapse formation and T cell activation[@grakoui1999].
Signaling and Regulation
Transcriptional Regulation
- [NF-κB](/entities/nf-kb) pathway: Primary transcriptional regulator; ICAM1 promoter contains multiple NF-κB binding sites[@collins1995]
- AP-1: Cooperates with NF-κB for maximal expression
- IFN regulatory factors (IRFs): Contribute to interferon-induced expression
Cytokine Regulation
- TNF-α: Strongly induces ICAM1 expression via NF-κB[@dustin1986]
- IL-1β: Synergizes with TNF-α for maximum induction
- IFN-γ: Induces expression in astrocytes and [microglia](/cell-types/microglia-neuroinflammation)
- IL-17: Contributes to chronic inflammation
Post-translational Regulation
- Phosphorylation: Cytoplasmic tail phosphorylated on serine/threonine residues
- Glycosylation: Heavily N-glycosylated affecting ligand binding
- Soluble ICAM1: Produced by alternative splicing and proteolytic cleavage[^3]
Disease Associations
Alzheimer's Disease (AD)
ICAM1 plays a significant role in Alzheimer's disease pathogenesis[@akiyama2000][@grammas2011]:
- BBB dysfunction: Elevated ICAM1 in AD brain microvasculature contributes to blood-brain barrier breakdown[@zlokovic2008]
- Immune cell infiltration: Mediates peripheral immune cell (T cells, monocytes) trafficking into the brain[@michaud2013]
- Endothelial activation: Markers of endothelial activation correlate with disease severity[@blasko1999]
- Cerebral amyloid angiopathy (CAA): ICAM1 expression associated with amyloid deposits in vessels[@weller2009]
- Neuroinflammation: Facilitates microglial activation and proinflammatory cytokine production[@liu2018]
Parkinson's Disease (PD)
In Parkinson's disease, ICAM1 contributes to neuroinflammation and disease progression[@zerlauth1997]:
- Substantia nigra: Increased ICAM1 expression in dopaminergic neuron region[@mcgeer1988]
- Microglial activation: Mediates microglial recruitment to injured neurons[@wang2019]
- CSF markers: Elevated soluble ICAM1 in cerebrospinal fluid of PD patients[@chen2018]
- [Blood-brain barrier](/entities/blood-brain-barrier): Contributes to BBB permeability in PD[@kortekaas2005]
Multiple Sclerosis (MS)
ICAM1 is crucial in MS pathophysiology[@sobel1993]:
- Immune cell trafficking: Critical for T cell transmigration across the blood-brain barrier[@cannella1998]
- Lesion formation: Elevated in active demyelinating lesions[@lee1999]
- Therapeutic target: Natalizumab blocks α4-integrin, preventing ICAM1-mediated adhesion[@polman2006]
- Clinical correlations: ICAM1 levels correlate with disease activity[@hartung1995]
Amyotrophic Lateral Sclerosis (ALS)
ICAM1 involvement in ALS[@baron2005]:
- Motor [cortex](/brain-regions/cortex): Upregulated in motor cortex of ALS patients[@kim2016]
- Spinal cord: Elevated expression in spinal cord regions with motor neuron loss[@rossi2012]
- Disease progression: Levels correlate with rate of disease progression[@fiala2010]
- Inflammatory infiltration: Mediates inflammatory cell infiltration into CNS[@britschgi2012]
Stroke and Traumatic Brain Injury (TBI)
ICAM1 mediates post-injury neuroinflammation[@beschorner2007][@sette2019]:
- Ischemic injury: Rapidly upregulated after stroke[@zhang1998]
- Reperfusion injury: Contributes to secondary damage after thrombolysis[@petty2009]
- BBB breakdown: Mediates leukocyte-dependent blood-brain barrier disruption[@nitta2003]
- Therapeutic potential: ICAM1 inhibitors show neuroprotective effects in preclinical models[@huang2000]
Expression Pattern
Basal Expression
- Low: Endothelial cells, epithelial cells, fibroblasts
- Intermediate: Leukocytes (constitutive on some subsets)
- Absent: Resting neurons, most glial cells
Induced Expression
- Endothelial cells: Strongly induced by TNF-α, IL-1β, IFN-γ[@dustin1986]
- [Microglia](/entities/microglia): Inducible expression in activated states[@lee1993]
- [Neurons](/entities/neurons): Induced under pathological conditions (injury, disease)[@andersson2005]
- [Astrocytes](/entities/astrocytes): Variable expression in reactive astrocytes[@saliba2014]
Brain Regional Distribution
- Cerebral cortex: Moderate expression on vasculature
- [Hippocampus](/brain-regions/hippocampus): Elevated in regions susceptible to neurodegeneration
- Substantia nigra: High expression in PD[@mcgeer1988]
- White matter: Associated with active demyelination in MS[@lee1999]
Therapeutic Targeting
Clinical Considerations
- Blood biomarker: Soluble ICAM1 (sICAM1) measurable in blood and CSF[@rentzos2009]
- Vascular inflammation marker: Elevated levels indicate systemic inflammation
- Therapeutic window: Timing critical - early intervention more effective
- Side effects: Immunosuppression risk with systemic blocking
Clinical Significance
Diagnostic Biomarkers
- Soluble ICAM1: Elevated in AD, PD, MS, stroke[@heppner2015]
- CSF/serum ratio: Reflects CNS inflammation status
- Longitudinal tracking: Levels correlate with disease progression[@zetterberg2016]
Prognostic Value
- Disease severity: Higher levels correlate with worse outcomes[@blasko1999]
- Treatment response: Changes may predict therapeutic efficacy
- Risk stratification: May identify patients at risk for progression
Research Applications
- Neuroimaging: ICAM1-PET ligands in development[@toth2015]
- Animal models: ICAM1 knockout mice show reduced neuroinflammation[@suminto2016]
- In vitro models: BBB-on-a-chip platforms incorporating ICAM1[@brown2015]
See Also
- [VCAM1 Gene](/proteins/vcam1-protein) - Vascular Cell Adhesion Molecule 1
- [PECAM1 Gene](/proteins/pecam1-protein) - Platelet Endothelial Cell Adhesion Molecule 1
- [SELE Gene](/proteins/sele-protein) - E-selectin
- [SELP Gene](/proteins/selp-protein) - P-selectin
- [TNF Gene](/proteins/tnf-protein) - Tumor Necrosis Factor
- [IL6 Gene](/proteins/il6-protein) - Interleukin 6
- [ITGAL Gene](/proteins/itgal-protein) - Integrin Alpha L (LFA-1)
- [ITGAM Gene](/proteins/itgam-protein) - Integrin Alpha M (Mac-1)
- [Neuroinflammation Pathway](/mechanisms/neuroinflammation-pathway)
- [Blood-Brain Barrier Dysfunction](/mechanisms/blood-brain-barrier-dysfunction)
- [TNF Signaling Pathway](/mechanisms/tnf-signaling-pathway)
- [Leukocyte Extravasation](/mechanisms/leukocyte-extravasation)
- [Alzheimer's Disease](/diseases/alzheimers-disease)
- [Parkinson's Disease](/diseases/parkinsons-disease)
- [Multiple Sclerosis](/diseases/multiple-sclerosis)
- [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
- [Vascular Dementia](/diseases/vascular-dementia)
Background
The study of Icam1 Intercellular Adhesion Molecule 1 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
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/) - Biomedical literature
- [Alzheimer's Disease Neuroimaging Initiative](https://adni.loni.usc.edu/) - Research data
- [Allen Brain Atlas](https://brain-map.org/) - Brain gene expression data
References
[Dustin ML, et al, (1986) (1986)](https://pubmed.ncbi.nlm.nih.gov/2426277/)
[Unknown, Springer TA (1994) (1994)](https://pubmed.ncbi.nlm.nih.gov/7515918/)
[Shimaoka M, et al, (2003) (2003)](https://pubmed.ncbi.nlm.nih.gov/12530978/)
[Unknown, Hynes RO (1992) (1992)](https://pubmed.ncbi.nlm.nih.gov/1534403/)
[Grakoui A, et al, (1999) (1999)](https://pubmed.ncbi.nlm.nih.gov/10535941/)
[Collins T, et al, (1995) (1995)](https://pubmed.ncbi.nlm.nih.gov/7544006/)
[Akiyama H, et al, (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10740211/)
[Grammas P, et al, (2011) (2011)](https://pubmed.ncbi.nlm.nih.gov/21827635/)
[Unknown, Zlokovic BV (2008) (2008)](https://pubmed.ncbi.nlm.nih.gov/18504134/)
[Michaud JP, et al, (2013) (2013)](https://pubmed.ncbi.nlm.nih.gov/23904614/)
[Blasko I, et al, (1999) (1999)](https://pubmed.ncbi.nlm.nih.gov/10563617/)
[Weller RO, et al, (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/19052761/)
[Liu CY, et al, (2018) (2018)](https://pubmed.ncbi.nlm.nih.gov/29593542/)
[Zerlauth G, et al, (1997) (1997)](https://pubmed.ncbi.nlm.nih.gov/9065546/)
[McGeer PL, et al, (1988) (1988)](https://pubmed.ncbi.nlm.nih.gov/2839804/)
[Wang Q, et al, (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/31801586/)
[Chen X, et al, (2018) (2018)](https://pubmed.ncbi.nlm.nih.gov/29482756/)
[Kortekaas R, et al, (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15639321/)
[Sobel RA, et al, (1993) (1993)](https://pubmed.ncbi.nlm.nih.gov/8423348/)
[Cannella B, et al, (1998) (1998)](https://pubmed.ncbi.nlm.nih.gov/9665969/)
[Lee SJ, et al, (1999) (1999)](https://pubmed.ncbi.nlm.nih.gov/10452439/)
[Polman CH, et al, (2006) (2006)](https://pubmed.ncbi.nlm.nih.gov/16428282/)
[Hartung HP, et al, (1995) (1995)](https://pubmed.ncbi.nlm.nih.gov/7668828/)
[Baron P, et al, (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15928031/)
[Kim J, et al, (2016) (2016)](https://pubmed.ncbi.nlm.nih.gov/27193190/)
[Rossi D, et al, (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22521928/)
[Fiala M, et al, (2010) (2010)](https://pubmed.ncbi.nlm.nih.gov/20525206/)
[Britschgi M, et al, (2012) (2012)](https://pubmed.ncbi.nlm.nih.gov/22531428/)
[Beschorner R, et al, (2007) (2007)](https://pubmed.ncbi.nlm.nih.gov/17286144/)
[Sette G, et al, (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/30595152/)
[Zhang RL, et al, (1998) (1998)](https://pubmed.ncbi.nlm.nih.gov/9596474/)
[Petty MA, et al, (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/18992725/)
[Nitta T, et al, (2003) (2003)](https://pubmed.ncbi.nlm.nih.gov/12514224/)
[Huang J, et al, (2000) (2000)](https://pubmed.ncbi.nlm.nih.gov/10864296/)
[Lee SC, et al, (1993) (1993)](https://pubmed.ncbi.nlm.nih.gov/7685795/)
[Andersson AK, et al, (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15644154/)
[Saliba DG, et al, (2014) (2014)](https://pubmed.ncbi.nlm.nih.gov/24803011/)
[Nimmerjahn A, et al, (2005) (2005)](https://pubmed.ncbi.nlm.nih.gov/15976022/)
[Gadek TR, et al, (2002) (2002)](https://pubmed.ncbi.nlm.nih.gov/11985456/)
[Kim ID, et al, (2014) (2014)](https://pubmed.ncbi.nlm.nih.gov/24811245/)
[Juric M, et al, (2019) (2019)](https://pubmed.ncbi.nlm.nih.gov/30627956/)
[Rentzos M, et al, (2009) (2009)](https://pubmed.ncbi.nlm.nih.gov/19157788/)
[Heppner FL, et al, (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/25582439/)
[Zetterberg M, et al, (2016) (2016)](https://pubmed.ncbi.nlm.nih.gov/26739571/)
[Toth M, et al, (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/26259033/)
[Suminto H, et al, (2016) (2016)](https://pubmed.ncbi.nlm.nih.gov/26911613/)
[Brown TD, et al, (2015) (2015)](https://pubmed.ncbi.nlm.nih.gov/25585117/)Pathway Diagram
The following diagram shows the key molecular relationships involving ICAM1 - Intercellular Adhesion Molecule 1 discovered through SciDEX knowledge graph analysis:
Mermaid diagram (expand to render)