# Cystinosis and Cellular Energy Failure: Mitochondria at the Crossroads

## TL;DR

Cystinosis causes kidney and multi-organ damage by disrupting lysosomal and mitochondrial function, leading to energy failure and oxidative stress.

## Contribution

The paper highlights novel organelle communication mechanisms between lysosomes and mitochondria in cystinosis.

## Key findings

- Mitochondrial dysfunction in cystinosis includes impaired oxidative phosphorylation and increased reactive oxygen species.
- Disrupted lysosome-mitochondria communication leads to defective mitophagy and energy failure.
- Therapeutic strategies targeting mitochondrial health and autophagy may offer new treatment options.

## Abstract

Cystinosis is a rare lysosomal storage disorder characterized by defective cystine transport and progressive multi-organ damage, with the kidney being the primary site of pathology. In addition to the traditional perspective on lysosomal dysfunction, recent studies have demonstrated that cystinosis exerts a substantial impact on cellular energy metabolism, with a particular emphasis on oxidative pathways. Mitochondria, the central hub of ATP production, exhibit structural abnormalities, impaired oxidative phosphorylation, and increased reactive oxygen species. These factors contribute to proximal tubular cell failure and systemic complications. This review highlights the critical role of energy metabolism in cystinosis and supports the emerging idea of organelle communication. A mounting body of evidence points to a robust functional and physical association between lysosomes and mitochondria, facilitated by membrane contact sites, vesicular trafficking, and signaling networks that modulate nutrient sensing, autophagy, and redox balance. Disruption of these interactions in cystinosis leads to defective mitophagy, accumulation of damaged mitochondria, and exacerbation of oxidative stress, creating a vicious cycle of energy failure and cellular injury. A comprehensive understanding of these mechanisms has the potential to reveal novel therapeutic avenues that extend beyond the scope of cysteamine, encompassing strategies that target mitochondrial health, enhance autophagy, and restore lysosome–mitochondria communication.