### APLNR Gene Overview

**Gene Symbol**: APLNR  
**Entrez Gene ID**: 9442  
**Location**: Chromosome 1

The APLNR (apelin receptor) gene encodes a G protein-coupled receptor (GPCR) that is primarily activated by the peptides apelin and APELA. This receptor is involved in multiple physiological processes, particularly in the cardiovascular system, metabolism, embryonic development, and angiogenesis.

### 1. Associated Genes

**Notable Associated Genes**:
- **APLN**: Encodes the apelin peptide, which is the primary ligand for the APLNR receptor.
- **APELA**: Encodes the apelin receptor early endogenous ligand, another ligand for APLNR.
- **EDN1**: Endothelin-1, involved in vasoconstriction which is counter-regulated by apelin signaling.
- **ACE**: Angiotensin-converting enzyme, which is involved in the renin-angiotensin-aldosterone system (RAAS), regulating blood pressure and fluid balance.

### 2. Aging and Age-Related Diseases

The APLNR gene has been implicated in several age-related conditions:

- **Hypertension**: As APLNR exhibits a counter-regulatory role against the hypertensive effects of angiotensin II, dysregulation of this pathway may contribute to the development of hypertension, especially in older adults.
- **Heart Failure**: The receptor plays a role in heart contractility and has been associated with heart failure, which is more prevalent in aging populations.
- **Metabolic Disorders**: The involvement of apelin signaling in glucose metabolism suggests potential links to age-related metabolic disorders, such as type 2 diabetes.
- **Age-Related Vascular Diseases**: The role of APLNR in angiogenesis implies its involvement in conditions like atherosclerosis and other age-related vascular complications.

### 3. Drug Interactions

Currently, there are limited direct drug interactions specifically targeting the APLNR. However, drugs that influence blood pressure and cardiovascular health may indirectly affect APLNR-related pathways:

- **Angiotensin Receptor Blockers (ARBs)**: These medications, such as losartan and valsartan, may interact indirectly with APLNR signaling due to the relationship with the renin-angiotensin system.
- **ACE Inhibitors**: Similar to ARBs, ACE inhibitors such as lisinopril may affect the APLNR pathway through the modulation of angiotensin II levels.

### 4. Pathways and Biological Processes

APLNR is involved in several critical biological pathways:

- **APELIN signaling pathway**: Activation of APLNR regulates various downstream signaling events and physiological processes.
- **G Protein-Coupled Receptor Signaling**: Inhibiting adenylate cyclase activity is a significant function, leading to various cellular responses.
- **Angiogenesis and Vasculogenesis**: APLNR plays a crucial role in blood vessel formation during embryonic development and in adults.
- **Regulation of Blood Pressure**: Through its actions in vascular smooth muscle and endothelial cells, APLNR contributes to the maintenance of blood pressure homeostasis.
- **Molecular Mechanisms in Cancer**: APLNR is involved in tumor angiogenesis, affecting the growth of tumors and their ability to form a vascular supply.

### Summary

The APLNR gene is a multifunctional GPCR that is integral to cardiovascular health, embryonic development, and metabolic processes. Its interactions and regulatory mechanisms make it a target of interest for understanding various physiological and pathological conditions, particularly those related to aging and age-associated diseases.