### XPNPEP1 Gene Overview

**Gene Symbol:** XPNPEP1  
**Location:** Chromosome 19

**Function:**  
XPNPEP1 encodes a cytosolic metalloaminopeptidase known to specifically cleave the N-terminal amino acid adjacent to a proline residue in various peptides. This activity is crucial for the degradation and maturation of several bioactive peptides, including tachykinins, neuropeptides, and peptide hormones. The enzyme also contributes to the catabolism of bradykinin, a peptide that plays a role in blood pressure regulation and inflammatory responses.

### Additional Associated Genes
While the gene summaries provided do not link specific genes directly to XPNPEP1, it is often associated with regulatory networks related to peptide metabolism and signaling. Potential associated genes based on functional pathways include:

- **ACE (Angiotensin Converting Enzyme)**: Known to interact with bradykinin signaling pathways.
- **ADAM33 and EMT (Endothelin-converting enzyme)**: Associated with neuropeptide metabolism and processing of pro-hormones.
  
### Age-Related Associations
XPNPEP1 has been implicated in processes that could affect aging and age-related diseases, particularly through its role in neuropeptide degradation. Though specific studies linking XPNPEP1 directly to aging are limited, alterations in peptide metabolism are known to impact:

- **Neurodegenerative diseases**: Abnormal processing of neuropeptides can contribute to diseases such as Alzheimer's.
- **Cardiovascular aging**: Dysregulation in bradykinin degradation could influence age-related hypertension.

Research has suggested that enzymes involved in peptide metabolism, including metalloaminopeptidases, may have critical roles in the pathophysiology of conditions commonly associated with aging.

### Drug Interactions
While no specific drugs are universally recognized to directly target XPNPEP1, inhibitors or modulators targeting related pathways may indirectly affect its activity. Potential drug classes that could influence XPNPEP1 activity include:

- **ACE inhibitors**: Used to lower blood pressure by inhibiting the conversion of angiotensin I to angiotensin II, these drugs might indirectly affect the concentrations of peptides influenced by XPNPEP1.
- **Bradykinin antagonists**: Could potentially interact with the pathways that involve the function of XPNPEP1.

### Pathways and Biological Processes
XPNPEP1 is involved in multiple biological processes and signaling pathways:

1. **Peptide metabolism**: It plays a significant role in the processing and degradation of peptides, particularly neuroactive peptides and hormones.
2. **Calcium signaling pathways**: As bradykinin can mediate calcium signaling, XPNPEP1's activity on this peptide impacts cardiovascular and immune response pathways.
3. **Neuropeptide signaling**: Crucial for neuropeptide maturation and signaling, linking to pain sensation, inflammation, and neurodegenerative processes.

In summary, XPNPEP1’s enzymatic activity in cleaving prolyl residues positions it as a critical player in both normal physiological processes and pathophysiological conditions, particularly those associated with age and neurodegeneration. Further research could provide deeper insights into its role in aging and potential therapeutic targets.