NOS3 — Nitric Oxide Synthase 3

NOS3 — Nitric Oxide Synthase 3

Introduction

Pathway Diagram

```mermaid
flowchart TD
NOS3["NOS3<br/>(Endothelial NOS)"]
NO["Nitric Oxide<br/>Production"]
SIRT1["SIRT1<br/>(Sirtuin 1)"]
NFE2L2["NFE2L2<br/>(Nrf2)"]
MTOR["MTOR<br/>(mTOR Complex)"]
BECN1["BECN1<br/>(Beclin-1)"]
FOXO1["FOXO1<br/>(FoxO1)"]
MAP3K5["MAP3K5<br/>(ASK1)"]
STING1["STING1<br/>(STING)"]

Stroke["Stroke<br/>Protection"]
Ischemia["Ischemic<br/>Injury"]
MS["Multiple<br/>Sclerosis"]
Autophagy["Autophagy<br/>Regulation"]
Oxidative["Oxidative<br/>Stress"]
Inflammation["Neuroinflammation"]
Apoptosis["Cell Death<br/>Pathways"]
Neuroprotection["Neuroprotection"]

NOS3 -->|"produces"| NO
NO -->|"activates"| SIRT1
NO -->|"activates"| NFE2L2
SIRT1 -->|"enhances"| NFE2L2
NFE2L2 -->|"reduces"| Oxidative

NOS3 -->|"inhibits"| MTOR
MTOR -->|"inhibits"| BECN1
BECN1 -->|"promotes"| Autophagy
SIRT1 -->|"activates"| FOXO1
FOXO1 -->|"promotes"| Autophagy

NOS3 -->|"inhibits"| MAP3K5
MAP3K5 -->|"promotes"| Apoptosis
NOS3 -->|"modulates"| STING1
STING1 -->|"promotes"| Inflammation

NO -->|"protects_against"| Stroke
NO -->|"reduces"| Ischemia
NOS3 -->|"therapeutic_for"| MS
Autophagy -->|"promotes"| Neuroprotection
NFE2L2 -->|"promotes"| Neuroprotection

NOS3 — Nitric Oxide Synthase 3

Introduction

Pathway Diagram

Nos3 — Nitric Oxide Synthase 3 is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-gene"> [@balligand2009]
<table> [@kone2012]
<tr><th colspan="2" style="background:#f8f9fa;text-align:center;font-size:1.2em;">NOS3</th></tr> [@godecke2002]
<tr><td colspan="2" style="text-align:center;font-style:italic;">Nitric Oxide Synthase 3</td></tr> [@huang2001]
<tr><th style="width:40%;">Gene Symbol</th><td>NOS3</td></tr>
<tr><th>Full Name</th><td>Nitric Oxide Synthase 3</td></tr>
<tr><th>Chromosome</th><td>7q36</td></tr>
<tr><th>NCBI Gene ID</th><td>[4846](https://www.ncbi.nlm.nih.gov/gene/4846)</td></tr>
<tr><th>Ensembl ID</th><td>[ENSG00000138771](https://www.ensembl.org/Homo_species/Gene/Summary?g=ENSG00000138771)</td></tr>
<tr><th>OMIM</th><td>[163729](https://www.omim.org/entry/163729)</td></tr>
<tr><th>UniProt ID</th><td>[Q9UHD5](https://www.uniprot.org/uniprot/Q9UHD5)</td></tr>
<tr><th>Associated Diseases</th><td>Alzheimer's Disease, Vascular Dementia, Stroke, Cardiovascular Disease</td></tr>
<tr><th>Expression</th><td>Endothelium, Brain, Platelets, Cardiomyocytes</td></tr>
</table>
</div>

Overview

NOS3 (Nitric Oxide Synthase 3), also known as endothelial nitric oxide synthase (eNOS), is a gene located on chromosome 7q36 that encodes the endothelial isoform of nitric oxide synthase. This enzyme is primarily expressed in vascular endothelial cells where it produces nitric oxide (NO) that regulates blood flow, blood pressure, and vascular homeostasis.

Function

NOS3 produces nitric oxide in endothelial cells:

• Regulates vascular tone and blood pressure
• Controls blood flow to the brain (cerebral circulation)
• Inhibits platelet adhesion and aggregation
• Protects against atherosclerosis
• Regulates angiogenesis (new blood vessel formation)

Disease Associations

Alzheimer's Disease

NOS3 dysfunction may contribute to AD pathogenesis:

• Reduced cerebral blood flow in AD patients
• Vascular contributions to cognitive impairment
• Endothelial dysfunction and [blood-brain barrier](/entities/blood-brain-barrier) breakdown
• Interactions with amyloid pathology

Vascular Dementia

• NOS3 plays a key role in cerebral vascular function
• Endothelial NO deficiency may contribute to vascular cognitive impairment
• Reduced NO affects learning and memory

Stroke

• NOS3 is protective in acute ischemic stroke
• NO maintains cerebral blood flow
• Endothelial dysfunction increases stroke risk

Therapeutic Implications

• NOS3 activity can be enhanced by statins, ACE inhibitors, and exercise
• L-arginine supplementation has been explored
• Targeting endothelial dysfunction in AD is an active research area

Key Publications

See Also

• [Nitric Oxide](/entities/nitric-oxide)
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Vascular Dementia](/diseases/vascular-dementia)
• [Cerebral Blood Flow](/entities/cerebral-blood-flow)

External Links

• [NCBI Gene: NOS3](https://www.ncbi.nlm.nih.gov/gene/4846)
• [UniProt: NOS3](https://www.uniprot.org/uniprot/Q9UHD5)

Endothelial Function

Blood Flow Regulation

• Basal NO production maintains vascular tone
• Shear stress increases NOS3 activity
• NO causes vasodilation via cGMP pathway
• Essential for blood pressure regulation

Blood-Brain Barrier

• Regulates endothelial tight junctions
• Protects against blood-brain barrier breakdown
• Dysfunction contributes to neurovascular damage

Disease Mechanisms

Cerebral Small Vessel Disease

• Reduced NOS3 contributes to small vessel disease
• Impaired autoregulation of cerebral blood flow
• White matter lesions in aging brain

Vascular Cognitive Impairment

• Endothelial dysfunction is a key contributor
• NO deficiency affects neuronal function
• Interaction with Alzheimer's pathology

Background

The study of Nos3 — Nitric Oxide Synthase 3 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.

References

Pathway Diagram

The following diagram shows the key molecular relationships involving NOS3 — Nitric Oxide Synthase 3 discovered through SciDEX knowledge graph analysis: