ITGAM Gene

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ITGAM Gene

Overview

Itgam Gene plays an important role in the study of neurodegenerative diseases. This page provides comprehensive information about this topic, including its mechanisms, significance in disease processes, and therapeutic implications.

Introduction

ITGAM encodes integrin alpha M (CD11b), the alpha chain of the heterodimeric receptor alphaMbeta2 (CR3/Mac-1) with [ITGB2](/genes/itgb2). In the CNS this receptor is central to myeloid adhesion, complement-opsonin recognition, phagocytosis, and inflammatory signal integration in [microglia](/cell-types/microglia).[@ross2000][@schartz2020]

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ITGAM Gene

Overview

Mermaid diagram (expand to render)

Introduction

<div class="infobox infobox-gene">
<table>
<tr><th>Gene Symbol</th><td>ITGAM</td></tr>
<tr><th>Full Name</th><td>Integrin Subunit Alpha M (CD11b)</td></tr>
<tr><th>Chromosomal Location</th><td>16p11.2</td></tr>
<tr><th>NCBI Gene ID</th><td>3684</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000169896</td></tr>
<tr><th>UniProt ID</th><td>P11215</td></tr>
<tr><th>Major Complex</th><td>CR3 / Mac-1 (CD11b-CD18)</td></tr>
<tr>
<td class="label">Associated Diseases</td>
<td><a href="/wiki/als" style="color:#ef9a9a">Als</a>, <a href="/wiki/cancer" style="color:#ef9a9a">Cancer</a>, <a href="/wiki/cardiac" style="color:#ef9a9a">Cardiac</a>, <a href="/wiki/fibrosis" style="color:#ef9a9a">Fibrosis</a>, <a href="/wiki/inflammation" style="color:#ef9a9a">Inflammation</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">58 edges</a></td>
</tr>
</table>
</div>

Core Biology

CD11b/CD18 is a multifunctional immune receptor that binds complement fragment iC3b, ICAM-family ligands, fibrinogen, and damage-associated molecular patterns. In neurodegeneration-relevant contexts, ITGAM supports:

Adhesion and migration of myeloid cells
Recognition of complement-opsonized synapses and aggregates
Phagocytosis and respiratory burst signaling
Crosstalk with Toll-like and cytokine signaling pathways[@ross2000][@solovjov2015]

Because [complement system](/mechanisms/complement-system-neurodegeneration) activation is prominent in AD, PD, and ALS tissue, ITGAM is a mechanistically important bridge between complement deposition and effector microglial responses.[@schartz2020][@hong2016]

Role in Alzheimer's disease

In [Alzheimer's disease](/diseases/alzheimers-disease), CD11b-positive [microglia](/cell-types/microglia-neuroinflammation) accumulate near plaques and neuritic pathology. Complement tagging and CR3-dependent uptake can help clear cellular debris, yet persistent activation may also enhance synapse loss and inflammatory injury if not tightly regulated.[@schartz2020][@hong2016][@stevens2007]

This duality makes ITGAM relevant to therapeutic design: overly suppressing CR3 can impair clearance, while unchecked activation may amplify chronic neuroinflammation and circuit dysfunction.

Role in Parkinson's disease

In [Parkinson's disease](/diseases/parkinsons-disease), CD11b upregulation is consistently reported in activated microglia within nigrostriatal regions.[@tansey2019] Engagement of ITGAM-dependent signaling alongside [alpha-synuclein](/proteins/alpha-synuclein)-triggered innate immune pathways contributes to cytokine release and oxidative stress pressure on dopaminergic [neurons](/entities/neurons).[@tansey2019][@pajares2019]

In [amyotrophic lateral sclerosis](/diseases/amyotrophic-lateral-sclerosis), CD11b-positive myeloid responses track with disease progression in spinal cord and motor pathways.[@geloso2017] Similar ITGAM-associated signatures are observed in other disorders where [neuroinflammation](/mechanisms/microglia-neuroinflammation) and complement dysregulation are major pathogenic axes.

Pathway Context and Network Placement

ITGAM sits at the interface of immune recognition and tissue remodeling:

Injury or aggregate burden promotes complement activation and opsonization.

iC3b-coated targets are recognized by CR3 (ITGAM/ITGB2).

Cytoskeletal and kinase pathways drive engulfment and inflammatory transcription.

Net effect depends on disease stage, target type (debris vs synapse), and co-signaling via receptors such as [TREM2](/genes/trem2).[@schartz2020][@stevens2007][@deczkowska2018]

This connects ITGAM directly to [complement-mediated-synapse-loss](/mechanisms/complement-mediated-synapse-loss), [innate-immune-signaling-ad](/mechanisms/innate-immune-signaling-ad), and [selective-neuronal-vulnerability](/mechanisms/selective-neuronal-vulnerability).

Therapeutic and Biomarker Implications

Potential translational strategies include:

Tuning complement-CR3 signaling rather than complete pathway shutdown
Combining CR3-axis modulation with anti-aggregate therapies
Using tissue/imaging signatures of CD11b-high microglia as pharmacodynamic readouts in immune-modulating trials[@hong2016][@tansey2019][@deczkowska2018]

Because ITGAM is broadly expressed across myeloid populations, CNS-targeted approaches should account for peripheral immune effects and stage-dependent biology.

Open Questions

Which ITGAM signaling states are protective (clearance) versus pathogenic (synapse injury)?
How does ITGAM interact with [APOE](/genes/apoe)-[TREM2](/genes/trem2) programs across disease stages?
Can precision modulation of CR3 improve outcomes without compromising host defense or repair?

Disease Associations

Top DisGeNET gene-disease associations for this gene are listed below. Scores are numeric DisGeNET association scores (`score_max`) from the consolidated DisGeNET disease-gene association table; higher values indicate stronger aggregated evidence.

| Disease | DisGeNET score | Evidence sources | Supporting PMID count |
|---|---:|---|---:|
| systemic lupus erythematosus | 0.249 | BeFree/CTD_human/GAD/LHGDN | 29 |
| IgA glomerulonephritis | 0.212 | CTD_human/GAD | 2 |
| type 1 diabetes mellitus | 0.003 | BeFree/GAD | 5 |
| melanoma | 0.003 | BeFree/LHGDN | 4 |
| chronic obstructive pulmonary disease | 0.003 | BeFree/LHGDN | 3 |

Source: DisGeNET-derived consolidated disease-gene associations (`dhimmel/disgenet`, gene symbol `ITGAM`).

External Links

[NCBI Gene: ITGAM](https://www.ncbi.nlm.nih.gov/gene/3685)
[UniProt: ITGAM (P05106)](https://www.uniprot.org/uniprot/P05106)
[GeneCards: ITGAM](https://www.genecards.org/cgi-bin/carddisp.pl?gene=ITGAM)
[HGNC: ITGAM](https://www.genenames.org/data/hgnc_complete_set.txt?search=ITGAM)

Overview

Background

The study of Itgam Gene 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.

Genetics and Clinical Interpretation

Outside neurodegeneration, ITGAM coding variants are well studied in systemic autoimmune disease, showing that modest shifts in CR3 function can materially alter immune tone.[@ross2000][@solovjov2015] For CNS applications, this supports a precision-medicine view: genotype, disease stage, and inflammatory milieu likely determine whether CR3-axis modulation is beneficial or detrimental.

In translational neurodegeneration studies, CD11b is best interpreted as part of a panel that includes complement activation markers, microglial state programs, and neuronal injury biomarkers.[@schartz2020][@hong2016][@deczkowska2018] This multi-marker approach is important because high CD11b signal can reflect effective debris clearance, maladaptive synapse stripping, or mixed states coexisting in the same tissue region.

Intervention Logic in AD and PD Programs

For Alzheimer's disease, a plausible intervention strategy is staged modulation: preserve early CR3-dependent plaque compaction/clearance while limiting chronic complement-driven synaptic injury in later disease phases.[@hong2016][@stevens2007]

For Parkinson's disease, ITGAM-targeted approaches may need to be paired with therapies that reduce alpha-synuclein burden and oxidative injury to avoid isolated immune suppression without substrate control.[@tansey2019][@pajares2019][@geloso2017]

References

[Ross GD, Regulation of the adhesion versus cytotoxic functions of the Mac-1/CR3/alphaMbeta2-integrin glycoprotein (2000)](https://pubmed.ncbi.nlm.nih.gov/10906929/)

[Schartz ND, Tenner AJ, The good, the bad, and the opportunities of the complement system in neurodegenerative disease (2020)](https://doi.org/10.4049/jimmunol.1502069)

[Solovjov DA, Pluskota E, Plow EF, Distinct roles for the alpha and beta subunits in the functions of integrin alphaMbeta2 (2015)](https://doi.org/10.3389/fimmu.2015.00657)

[Hong S, Beja-Glasser VF, Nfonoyim BM, et al, Complement and microglia mediate early synapse loss in Alzheimer mouse models (2016)](https://doi.org/10.1126/science.aad8373)

[Stevens B, Allen NJ, Vazquez LE, et al, The classical complement cascade mediates CNS synapse elimination (2007)](https://doi.org/10.1016/j.cell.2007.10.036)

[Tansey MG, Romero-Ramos M, Immune system responses in Parkinson's disease: early and dynamic (2019)](https://doi.org/10.1016/S1474-4422(19)

[Pajares M, Rojo AI, Manda G, Bosca L, Cuadrado A, Inflammation in Parkinson's disease: mechanisms and therapeutic implications (2019)](https://doi.org/10.1016/j.cellsig.2019.109364)

[Geloso MC, Corvino V, Marchese E, Serrano A, Michetti F, D'Ambrosi N, The dual role of microglia in ALS: mechanisms and therapeutic approaches (2017)](https://doi.org/10.3389/fnagi.2017.00242)

[Deczkowska A, Keren-Shaul H, Weiner A, et al, Disease-associated microglia: a universal immune sensor of neurodegeneration (2018)](https://doi.org/10.1016/j.cell.2018.05.003)

Pathway Diagram

The following diagram shows the key molecular relationships involving ITGAM Gene discovered through SciDEX knowledge graph analysis:

Mermaid diagram (expand to render)

Expression Profile

Sources: [GTEx Portal v10](https://gtexportal.org/home/gene/itgam) | [Allen Brain Atlas](https://www.brain-map.org/)

GTEx Tissue Expression (median TPM)

| Rank | Tissue | Median TPM |
|------|--------|------------|
| 1 | Whole Blood | 148.76 |
| 2 | Spleen | 47.89 |
| 3 | Lung | 30.61 |
| 4 | Adipose Visceral Omentum | 15.05 |
| 5 | Adipose Subcutaneous | 13.01 |
| 6 | Artery Coronary | 10.84 |
| 7 | Nerve Tibial | 9.83 |
| 8 | Artery Aorta | 8.45 |
| 9 | Small Intestine Terminal Ileum | 7.78 |
| 10 | Brain Spinal cord cervical c-1 | 7.25 |
| 11 | Adrenal Gland | 6.64 |
| 12 | Bladder | 6.57 |
| 13 | Cells EBV-transformed lymphocytes | 6.33 |
| 14 | Esophagus Gastroesophageal Junction | 6.11 |
| 15 | Esophagus Muscularis | 6.10 |

Brain-Region Expression:

| Region | Median TPM |
|--------|------------|
| Brain Spinal cord cervical c-1 | 7.25 |

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ITGAM Gene

ITGAM Gene

Overview

Introduction

ITGAM Gene

Overview

Introduction

Core Biology

Role in Alzheimer's disease

Role in Parkinson's disease

Role in ALS and related disorders

Pathway Context and Network Placement

Therapeutic and Biomarker Implications

Open Questions

Disease Associations

See Also

External Links

Overview

Background

Genetics and Clinical Interpretation

Intervention Logic in AD and PD Programs

References

Pathway Diagram

Expression Profile

GTEx Tissue Expression (median TPM)