REG3A — Regenerating Family Member 3 Alpha

REG3A — Regenerating Family Member 3 Alpha

Overview

REG3A — Regenerating Family Member 3 Alpha

Overview

<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">REG3A — Regenerating Family Member 3 Alpha</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td>REG3A</td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>Regenerating Family Member 3 Alpha</td>
</tr>
<tr>
<td class="label">Aliases</td>
<td>HIP, PAP, REG3</td>
</tr>
<tr>
<td class="label">Chromosomal Location</td>
<td>2p12</td>
</tr>
<tr>
<td class="label">NCBI Gene ID</td>
<td>64084</td>
</tr>
<tr>
<td class="label">Ensembl ID</td>
<td>ENSG00000138231</td>
</tr>
<tr>
<td class="label">UniProt ID</td>
<td>Q9NZU5</td>
</tr>
<tr>
<td class="label">Tissue</td>
<td>Expression Level</td>
</tr>
<tr>
<td class="label">Pancreas</td>
<td>Highest (islet cells)</td>
</tr>
<tr>
<td class="label">Liver</td>
<td>High</td>
</tr>
<tr>
<td class="label">Small Intestine</td>
<td>High (enterocytes)</td>
</tr>
<tr>
<td class="label">Brain</td>
<td>Low to moderate</td>
</tr>
<tr>
<td class="label">Spinal Cord</td>
<td>Low</td>
</tr>
<tr>
<td class="label">Peripheral Nerve</td>
<td>Inducible</td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>

REG3A (Regenerating Family Member 3 Alpha), also known as HIP/PAP (Hepatocyte-Intestine-Pancreas/Reg III), is a secreted C-type lectin belonging to the Reg family of proteins. Initially characterized for its regenerative properties in pancreatic and hepatic tissues, emerging evidence suggests REG3A exerts neuroprotective effects in the central nervous system, making it a protein of interest in neurodegenerative disease research.

Gene Information

Protein Structure and Function

Structural Features

REG3A is a 175-amino acid secreted protein with a C-type lectin-like domain (CTLD) at its C-terminus. The protein forms a hexameric structure in solution, which is thought to facilitate its regenerative and protective functions[@bertrand2013]. Unlike classical C-type lectins that require calcium for carbohydrate binding, REG3A exhibits calcium-independent lectin activity, enabling stable interactions with bacterial cell wall peptidoglycans and potentially neuronal glycoconjugates[@kitagawa2010].

Biological Functions

REG3A participates in multiple biological processes:

Neuroprotective Mechanisms

Amyloid-Beta Neutralization

REG3A has been shown to interact with amyloid-beta (Aβ) plaques in Alzheimer's disease models. In vitro studies demonstrate that REG3A can reduce Aβ-induced neurotoxicity by preventing Aβ oligomerization and facilitating its clearance[@wang2022]. The lectin domain may recognize specific glycans on Aβ aggregates, neutralizing their pathogenic effects.

Neuroinflammation Modulation

REG3A modulates neuroinflammatory responses through inhibition of the [NF-κB](/entities/nf-kb) signaling pathway. In microglial cell models, REG3A treatment reduces production of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6[@chen2022]. This anti-inflammatory effect may be particularly relevant given the central role of chronic neuroinflammation in neurodegenerative disease progression.

Autophagy Induction

Emerging evidence suggests REG3A activates [autophagy](/entities/autophagy) in neuronal cells. Autophagy induction through [mTOR](/mechanisms/mtor-signaling-pathway)-independent pathways promotes clearance of damaged mitochondria and protein aggregates, both hallmarks of neurodegeneration[@zhang2021].

Axonal Regeneration

Following CNS injury, REG3A expression increases in [neurons](/entities/neurons) and glial cells. Functional studies demonstrate that exogenous REG3A promotes axonal regeneration through activation of the PI3K-Akt-mTOR signaling axis[@park2023].

Disease Associations

Alzheimer's Disease

REG3A expression is downregulated in Alzheimer's disease brains, particularly in the [hippocampus](/brain-regions/hippocampus) and temporal [cortex](/brain-regions/cortex)[@zhou2020]. This reduction correlates with disease severity, suggesting REG3A may serve a protective role that becomes compromised in AD. The protein's ability to neutralize Aβ and reduce neuroinflammation makes it a potential therapeutic target.

Parkinson's Disease

In Parkinson's disease models, REG3A has shown protective effects on dop protein appears to protect against mitochondrial dysfunction andaminergic neurons. The oxidative stress, both central to PD pathogenesis[@kim2022]. REG3A knockout mice exhibit increased vulnerability to MPTP-induced dopaminergic toxicity.

Peripheral Neuropathy

REG3A demonstrates protective effects in diabetic neuropathy models. Administration of REG3A improves nerve conduction velocities and reduces oxidative stress markers in peripheral nerves[@huang2020]. The mechanism involves activation of neurotrophic factor signaling and reduction of inflammatory demyelination.

Ischemic Stroke

REG3A expression increases following cerebral ischemia, suggesting a role in neuronal survival after stroke. Animal studies demonstrate that REG3A treatment reduces infarct size and improves functional recovery[@li2021]. The neuroprotective effects involve anti-apoptotic signaling through Bcl-2 family proteins and reduction of excitotoxic damage.

Amyotrophic Lateral Sclerosis

Preliminary studies indicate altered REG3A expression in ALS models and patient tissue. The protein may modulate excitotoxicity and neuroinflammation in motor neuron disease, though mechanistic understanding remains incomplete[@rodriguez2021].

Expression Pattern

Tissue Distribution

Regulation

REG3A expression is regulated by multiple factors:

• Pancreatic Duodenal Homeobox 1 (PDX1): Key transcriptional activator in pancreas
• Inflammatory Cytokines: IL-6 and TNF-α induce expression
• Nutritional Status: Fasting downregulates expression
• Cellular Stress: ER stress and oxidative stress induce expression

Therapeutic Potential

Recombinant Protein Therapy

The neuroprotective properties of REG3A have prompted investigation of recombinant protein as a therapeutic agent. Preclinical studies demonstrate that intravenous or intracerebroventricular administration of REG3A reduces pathology in AD and PD mouse models[@xu2022].

Gene Therapy

AAV-mediated REG3A overexpression represents an alternative therapeutic approach. Viral delivery of REG3A to the CNS achieves sustained protein expression and has shown efficacy in preclinical models of traumatic brain injury and neurodegenerative disease[@thompson2023].

Small Molecule Inducers

Identification of compounds that upregulate endogenous REG3A expression offers another therapeutic strategy. Natural compounds including curcumin and resveratrol have been shown to increase REG3A expression in neuronal cells[@yang2022].

Interacting Proteins and Pathways

Protein Interactions

• Albumin: Carrier protein in circulation
• TGF-β1: Synergistic effects on regeneration
• GDNF Family Ligands: Cross-talk in neurotrophic signaling
• Complement Proteins: Potential involvement in neuroinflammation

Signaling Pathways

• PI3K-Akt-mTOR: Cell survival and regeneration
• ERK1/2: Proliferation and differentiation
• NF-κB: Inflammation modulation
• JAK-STAT: Cytokine signaling

Genetic Variation

Polymorphisms

Single nucleotide polymorphisms (SNPs) in the REG3A gene have been associated with:

• Type 1 diabetes susceptibility
• Pancreatic insufficiency
• Inflammatory bowel disease

Cross-Links

• [GDNF Gene](/genes/gdnf) - Neurotrophic factor family
• [NTF3 Gene](/genes/ntf3) - Neurotrophin-3
• [BDNF Gene](/genes/bdnf) - Brain-derived neurotrophic factor
• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Neurotrophic Factors](/mechanisms/neurotrophic-factors)
• [Amyloid-Beta](/proteins/amyloid-beta)
• [Neuroinflammation](/mechanisms/neuroinflammation-pathway)

See Also

• [Alzheimer's Disease](/diseases/alzheimers-disease)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Amyloid-Beta](/proteins/amyloid-beta)
• [Neuroinflammation](/mechanisms/neuroinflammation-pathway)

External Links

• [Ensembl: ENSG00000138231](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000138231)

References

Pathway Diagram

The following diagram shows the key molecular relationships involving REG3A — Regenerating Family Member 3 Alpha discovered through SciDEX knowledge graph analysis: