### NPEPPS Gene Overview

**Gene Symbol**: NPEPPS  
**Full Name**: Puromycin-sensitive aminopeptidase  
**Gene Location**: The NPEPPS gene is located on human chromosome 17.

### 1. Associated Genes
The NPEPPS gene is known to interact with several other genes, particularly those involved in proteolytic pathways and neuropeptide regulation. Some associated genes include:

- **NTS** (Neurotensin): Involved in neuropeptide signaling.
- **PSEN1** (Presenilin 1): Mutations in this gene are associated with early onset Alzheimer's disease, connecting to NPEPPS's role in processing tau and other neuropeptides.
- **APP** (Amyloid precursor protein): Related to Alzheimer's disease; interactions can occur indirectly, as NPEPPS may influence neuropeptide processing that affects APP metabolism.
- **MTHFR** (Methylenetetrahydrofolate reductase): While not directly linked, genetic variability here may tie into metabolic processes affected by neuropeptides processed by NPEPPS.

### 2. Aging and Age-Related Diseases
Evidence suggests that NPEPPS may play a role in age-related diseases, particularly neurodegenerative conditions:

- **Alzheimer's Disease**: NPEPPS is involved in the catabolism of tau protein, which aggregates in Alzheimer’s disease. The efficiency of NPEPPS in processing normal tau compared to aggregated tau highlights its potential role in disease pathology.
- **Cellular Senescence**: Its involvement in the regulation of the cell cycle points to a possible role in cellular aging and senescence, although specific studies directly linking NPEPPS to aging processes are limited.
- **Neurodegeneration**: Dysregulation of NPEPPS may affect neuropeptide signaling that influences neuroinflammation and neuroprotection in aging.

### 3. Drug Interactions
Currently, there are no specific drug classes universally recognized for interacting with NPEPPS directly. However, potential therapeutic implications may involve:

- **Neuropeptide Receptor Modulators**: Since NPEPPS is involved in the regulation of neuropeptide activity, drugs modulating neuropeptide pathways (such as neurotensin antagonists) might indirectly influence NPEPPS activity.
- **Zinc Metallopeptidase Inhibitors**: While specific inhibitors targeted to NPEPPS are not well characterized, drugs affecting metalloprotease activity could theoretically influence its function.

### 4. Pathways and Biological Processes
NPEPPS is involved in several key biological processes:

- **Proteolysis**: NPEPPS is crucial for protein degradation. Its aminopeptidase activity allows for the trimming of proteins, especially in the context of antigen processing.
- **Antigen Processing and Presentation**: NPEPPS plays a role in the N-terminal trimming of precursors for cytotoxic T-cell epitope presentation, linking it to immune response and potentially autoimmune processes.
- **Neuropeptide signaling**: It regulates the bioactivity of numerous neuropeptides, thus influencing neuronal signaling, pain response, and other neurophysiological functions.
- **Cell Growth and Viability**: Its role in proteolytic events is essential for cell cycle regulation and can impact cellular functions vital for growth and survival.

### Conclusion
The NPEPPS gene is an important player in various biological processes, particularly in the brain and immune system, influencing both peptide metabolism and cell signaling. Understanding its intricate roles highlights its potential in aging and neurodegenerative diseases, warranting further research into targeted therapies and drug interactions.