GO:0045123 cellular extravasation: Leukocyte Transendothelial Migration, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0045123 cellular extravasation is the biological process by which a leukocyte migrates from the blood vessel lumen into surrounding tissue.
• The process requires sequential steps: capture and rolling, integrin activation, firm adhesion, transendothelial migration, and interstitial motility.
• Key molecular players include LFA-1 (ITGAL/ITGB2), CD44, GPR124, and endothelial junctional proteins.
• Cellular extravasation is not limited to leukocytes; tumor cells and iNKT17 cells can exploit related transendothelial migration programs during metastasis.
• Dysregulated extravasation contributes to Alzheimer's disease pathology, acute kidney injury, and cancer metastasis.
• CRISPR knockout, knock-in, and overexpression models enable causal testing of extravasation-related genes in endothelial and immune cell systems.
Description
Cellular extravasation (GO:0045123) is defined as the migration of a leukocyte from the blood vessels into the surrounding tissue. This process is fundamental to immune surveillance, inflammation, and host defense, and it represents the terminal step of the leukocyte adhesion cascade that begins with capture and rolling on activated endothelium. Understanding cellular extravasation is therefore central to immunology, vascular biology, and the pathophysiology of inflammatory and metastatic diseases. Beyond leukocytes, malignant cells and innate-like lymphocytes can co-opt transendothelial migration programs to disseminate, making this GO term relevant to cancer biology and neuroinflammation. Experimental evidence has linked extravasation defects to Alzheimer's disease-like pathology, acute kidney injury, and brain metastasis, underscoring its translational importance. Researchers studying this process require robust genetic models to dissect the contribution of individual adhesion and signaling molecules.
cellular extravasation At A Glance
| GO ID | GO:0045123 |
|---|---|
| GO term | cellular extravasation |
| Ontology | biological_process |
| Synonym | immune cell cellular extravasation; leucocyte cellular extravasation; leukocyte cellular extravasation; transendothelial leukocyte migration |
| Major function | Migration of a leukocyte from blood vessels into surrounding tissue |
| Cellular context | Vascular endothelium, leukocytes, and perivascular tissue |
| Disease relevance | Inflammation, neurodegeneration, acute kidney injury, cancer metastasis |
| Experimental models | Knockout, knock-in, overexpression, and library screening in endothelial and immune cells |
What Is GO:0045123?
In our own words, GO:0045123 cellular extravasation describes the directed movement of a leukocyte out of the blood vessel lumen, across the endothelial barrier, and into the surrounding tissue. It encompasses the coordinated steps of adhesion, transendothelial migration, and entry into the interstitial space, and is synonymous with transendothelial leukocyte migration.
Why Is cellular extravasation Important in Cell Biology?
Cellular extravasation is a rate-limiting step in immune cell recruitment and a critical determinant of tissue damage in inflammatory disease. It also represents a therapeutic bottleneck in cancer, where tumor cells and iNKT17 cells exploit transendothelial migration to seed distant organs. Because the process is genetically tractable, it serves as a model for studying adhesion, signaling, and barrier biology.
• Required for leukocyte delivery to sites of infection and injury.
• Dysregulated in Alzheimer's disease, where neutrophils promote pathology via LFA-1 integrin.
• Contributes to acute kidney injury through lung intravascular neutrophil retention.
• Exploited by tumor cells during brain and liver metastasis.
• Involves CD44 and GPR124 in trans-endothelial migration of cancer stem cell-derived pericytes.
• Regulated by endothelial junctional and adhesion molecules.
• Target for anti-inflammatory and anti-metastatic therapeutic strategies.
• Studied using CRISPR knockout and knock-in models of adhesion receptors.
• Relevant to nanomedicine design via transcytosis-enabled active extravasation.
• Provides a paradigm for understanding barrier crossing in multiple tissues.
What Happens During cellular extravasation?
Capture and Rolling
In simple terms: The leukocyte first slows down by briefly sticking to the blood vessel wall.
Leukocytes are captured from flowing blood and roll along activated endothelium through transient adhesion interactions. This initial step is prerequisite for subsequent firm adhesion and is part of the leukocyte adhesion cascade.
Integrin Activation and Firm Adhesion
In simple terms: The cell strengthens its grip on the vessel wall so it can stop.
LFA-1 integrin (ITGAL/ITGB2) mediates firm adhesion of leukocytes to endothelial ligands, a step required for subsequent extravasation. Neutrophils use LFA-1 to promote Alzheimer's disease-like pathology and cognitive decline.
Transendothelial Migration
In simple terms: The cell squeezes through the endothelial cell layer.
The leukocyte migrates across the endothelial barrier, a process termed transendothelial leukocyte migration. CD44-positive lung cancer stem cell-derived pericyte-like cells use GPR124 to enhance trans-endothelial migration during brain metastasis.
Interstitial Motility and Tissue Entry
In simple terms: Once outside the vessel, the cell moves into the tissue.
After crossing the endothelium, the leukocyte enters the surrounding tissue interstitium. In acute kidney injury, lung intravascular neutrophil retention reduces capillary blood flow, highlighting the physiological impact of extravasation dynamics.
Extravasation in Non-Leukocyte Contexts
In simple terms: Other cell types can also leave blood vessels using similar machinery.
Tissue-resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22. Tumor nanomedicine can exploit transcytosis-enabled active extravasation for drug delivery. Lung endothelium exploits susceptible tumor cell states to instruct metastatic latency.
Key Genes Involved in GO:0045123 cellular extravasation
The following genes and proteins are experimentally implicated in cellular extravasation and related transendothelial migration processes.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ITGAL | Integrin alpha L (LFA-1) subunit mediating firm adhesion | Neutrophil-driven Alzheimer's pathology |
| ITGB2 | Integrin beta 2 (LFA-1) subunit mediating firm adhesion | Leukocyte extravasation in inflammation |
| CD44 | Cell surface adhesion receptor on cancer stem cell-derived pericytes | Brain metastasis via GPR124-enhanced trans-endothelial migration |
| GPR124 | Orphan G-protein coupled receptor enhancing trans-endothelial migration | Brain metastasis of CD44+ lung cancer cells |
| IL22 | Cytokine facilitating cancer cell extravasation | Liver metastasis via iNKT17 cells |
| ICAM1 | Endothelial ligand for LFA-1 | Leukocyte firm adhesion |
| ICAM2 | Endothelial adhesion molecule | Transendothelial migration |
| VCAM1 | Endothelial adhesion molecule for integrins | Leukocyte recruitment |
| SELE | E-selectin mediating rolling | Leukocyte capture |
| SELP | P-selectin mediating rolling | Leukocyte capture |
| CXCL8 | Chemokine activating neutrophil integrins | Neutrophil extravasation |
| CXCR2 | Chemokine receptor on neutrophils | Neutrophil retention and extravasation |
| PECAM1 | Endothelial junctional adhesion molecule | Transendothelial migration |
| CD99 | Endothelial junctional protein | Leukocyte diapedesis |
| JAM-A | Junctional adhesion molecule | Endothelial barrier regulation |
| ESAM | Endothelial cell-selective adhesion molecule | Leukocyte transmigration |
| VIM | Vimentin cytoskeletal protein | Cell motility during extravasation |
| ACTB | Actin cytoskeleton | Cell migration machinery |
How Is cellular extravasation Regulated?
Cellular extravasation is regulated by chemokine gradients, integrin activation states, and endothelial junctional remodeling. Neutrophil retention in lung capillaries during acute kidney injury is modulated by hypoxemia and capillary blood flow. Endothelial cells can instruct tumor cell states to influence metastatic latency, indicating active regulation of extravasation permissiveness. Interleukin-22 from iNKT17 cells regulates cancer cell extravasation in liver metastasis.
cellular extravasation and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ITGAL/ITGB2 | Alzheimer's disease-like pathology | Knockout mice or human iPSC-derived neutrophils |
| IL22 | Liver metastasis | Knockout or overexpression in iNKT17 cells |
| CD44/GPR124 | Brain metastasis | Knockdown or knock-in in lung cancer stem cells |
| CXCR2 | Acute kidney injury | Endothelial-specific knockout |
| PECAM1/CD99 | Leukocyte diapedesis defects | Endothelial knockout or point mutation |
Alzheimer's Disease
Neutrophils promote Alzheimer's disease-like pathology and cognitive decline via LFA-1 integrin, linking cellular extravasation to neurodegeneration.
Acute Kidney Injury
Acute kidney injury triggers hypoxemia by lung intravascular neutrophil retention that reduces capillary blood flow, demonstrating systemic consequences of dysregulated neutrophil extravasation.
Cancer Metastasis
Tissue-resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22. CD44+ lung cancer stem cell-derived pericyte-like cells cause brain metastases through GPR124-enhanced trans-endothelial migration. Lung endothelium exploits susceptible tumor cell states to instruct metastatic latency.
Nanomedicine and Drug Delivery
Transcytosis-enabled active extravasation of tumor nanomedicine represents a therapeutic strategy exploiting extravasation pathways.
From cellular extravasation-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does LFA-1 mediate neutrophil extravasation in neurodegeneration? | ITGAL knockout mouse |
| Does GPR124 enhance trans-endothelial migration in brain metastasis? | GPR124 knockout or knock-in in cancer cells |
| Does IL-22 from iNKT17 cells promote liver metastasis? | IL22 knockout mouse |
| Does CXCR2 regulate neutrophil retention in acute kidney injury? | CXCR2 knockout or overexpression |
| Can endothelial junctional proteins be tagged to track diapedesis? | Tagged knock-in of PECAM1 or CD99 |
| Does CD44 overexpression drive pericyte-like trans-endothelial migration? | CD44 overexpression in lung cancer cells |
How to Study the cellular extravasation Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Intravital microscopy | Real-time leukocyte-endothelial interactions | In vivo extravasation dynamics |
| Flow adhesion assay | Integrin-dependent capture and firm adhesion | Leukocyte adhesion cascade |
| CRISPR knockout | Loss-of-function effects on extravasation | Causal gene testing |
| CRISPR knock-in | Tagged protein localization and function | Junctional protein tracking |
| RNA-seq | Transcriptional changes during migration | Endothelial activation states |
| Proteomics | Protein abundance and modifications | Adhesion complex composition |
| Transwell migration assay | Transendothelial migration capacity | In vitro extravasation model |
| Nanoparticle transcytosis assay | Active extravasation of nanomedicine | Drug delivery optimization |
Intravital Microscopy
Intravital imaging allows real-time visualization of leukocyte rolling, adhesion, and transendothelial migration in live animals.
Flow Cytometry and Adhesion Assays
Flow-based adhesion assays quantify integrin-dependent capture and firm adhesion of leukocytes to endothelial monolayers.
Genetic Knockout and Knock-in Models
CRISPR-generated knockout and knock-in models enable causal testing of genes such as ITGAL, CD44, and GPR124 in extravasation.
Transcriptomics and Proteomics
RNA-seq and proteomics of endothelial and immune cells identify regulators of transendothelial migration.
How CRISPR Can Be Used to Study GO:0045123 cellular extravasation
Knockout
CRISPR knockout of ITGAL, ITGB2, CD44, or GPR124 in endothelial or immune cells abolishes specific steps of cellular extravasation, enabling causal inference.
Point Mutation
Point mutations in integrin ligand-binding domains or GPR124 signaling motifs can dissect residue-level contributions to transendothelial migration.
Knock-in
Tagged knock-in of PECAM1, CD99, or ESAM allows live tracking of junctional remodeling during leukocyte diapedesis.
Overexpression
Overexpression of CD44 or IL22 in cancer cells enhances extravasation and metastasis in vivo, validating gain-of-function mechanisms.
How EDITGENE Supports cellular extravasation Research
Researchers studying cellular extravasation-related genes often need to determine whether a candidate gene is causally involved in leukocyte or tumor cell transendothelial migration. EDITGENE provides CRISPR-based models to test these hypotheses with precision.
Contact EDITGENE today to design your custom CRISPR model for cellular extravasation research.
Frequently Asked Questions About cellular extravasation
What is cellular extravasation?
Cellular extravasation (GO:0045123) is the migration of a leukocyte from the blood vessels into the surrounding tissue.
What genes are involved in cellular extravasation?
Key genes include ITGAL, ITGB2, CD44, GPR124, IL22, ICAM1, VCAM1, and PECAM1.
What are the steps of leukocyte extravasation?
The steps include capture and rolling, integrin activation, firm adhesion, transendothelial migration, and interstitial motility.
How is cellular extravasation studied?
It is studied using intravital microscopy, flow adhesion assays, CRISPR knockout models, and transcriptomics.
What diseases involve defective cellular extravasation?
Alzheimer's disease, acute kidney injury, and cancer metastasis involve dysregulated extravasation.
What is the role of LFA-1 in extravasation?
LFA-1 integrin (ITGAL/ITGB2) mediates firm adhesion of leukocytes to endothelium, a required step for extravasation.
How does CD44 contribute to brain metastasis?
CD44-positive lung cancer stem cell-derived pericyte-like cells use GPR124 to enhance trans-endothelial migration during brain metastasis.
Can CRISPR be used to study cellular extravasation?
Yes, CRISPR knockout, knock-in, and overexpression models enable causal testing of extravasation genes.
What is transendothelial leukocyte migration?
It is a synonym for cellular extravasation, describing leukocyte passage across the endothelial barrier.
What is the role of interleukin-22 in extravasation?
Interleukin-22 from tissue-resident iNKT17 cells facilitates cancer cell extravasation in liver metastasis.
Conclusion
Cellular extravasation (GO:0045123) is a genetically tractable biological process central to immunity, inflammation, and cancer metastasis. CRISPR-based models provide powerful tools to dissect the molecular players and therapeutic potential of this pathway.
References
- 3. Giannou AD et al.. 2023. Tissue resident iNKT17 cells facilitate cancer cell extravasation in liver metastasis via interleukin-22.. Immunity 56(1):125-142.e12 PMID: 36630911
- 4. Huang Q et al.. 2023. CD44(+) lung cancer stem cell-derived pericyte-like cells cause brain metastases through GPR124-enhanced trans-endothelial migration.. Cancer Cell 41(9):1621-1636.e8 PMID: 37595587
- 5. Zenaro E et al.. 2015. Neutrophils promote Alzheimer's disease-like pathology and cognitive decline via LFA-1 integrin.. Nat Med 21(8):880-6 PMID: 26214837
- 6. Zhou Q et al.. 2022. Transcytosis-enabled active extravasation of tumor nanomedicine.. Adv Drug Deliv Rev 189:114480 PMID: 35952830
- 7. Komaru Y et al.. 2025. Acute kidney injury triggers hypoxemia by lung intravascular neutrophil retention that reduces capillary blood flow.. J Clin Invest 135(10) PMID: 40048367
- 8. Jakab M et al.. 2024. Lung endothelium exploits susceptible tumor cell states to instruct metastatic latency.. Nat Cancer 5(5):716-730 PMID: 38308117
