Uncomfortably numb: how Nav1.7 mediates paclitaxel-induced peripheral neuropathy

Fluocinolone Acetonide Enhances Anterograde Mitochondria Trafficking and Promotes Neuroprotection against Paclitaxel-Induced Peripheral Neuropathy

Paclitaxel (PTX)-induced peripheral neuropathy (PIPN) is a debilitating health condition which is a result of degeneration of peripheral nerves found in extremities. Currently, there are no established treatment methods that can prevent or protect from PIPN. Fluocinolone acetonide (FA) has been recently identified as a potential candidate for protection from PIPN. However, the fundamental mechanism of action is still unknown. In this study, we showed that enhanced anterograde mitochondrial movement in dorsal root ganglion (DRG) cells has a major role in FA-mediated neuroprotection in PIPN. In this study, cells were treated with PTX or FA along with their combination followed by mitochondrial fluorescence staining. Somal (proximal) and axonal (distal) mitochondria were selectively stained using a microfluidic compartmentalized chamber with different MitoTrackers blue and red, respectively, which we termed, the two-color staining approach. Results revealed that axons were protected from degeneration by the PTX effect when treated along with FA. PTX exposure alone resulted in low mitochondrial mobility in DRG cells. However, cotreatment with PTX and FA showed significant enhancement of anterograde trafficking of somal (proximal) mitochondria to distal axons. Similarly, cotreatment with FA restored mitochondrial mobility significantly. Overall, this study affirms that increasing mitochondrial recruitment into the axon by cotreatment with FA can be a worthwhile strategy to protect or prevent PIPN. The proposed two-color staining approach can be extended to study trafficking for other neuron-specific subcellular organelles.

Discovery of Potential Neuroprotective Agents against Paclitaxel-Induced Peripheral Neuropathy

Chemotherapy-induced neurotoxicity is a common adverse effect of cancer treatment. No medication has been shown to be effective in the prevention or treatment of chemotherapy-induced neurotoxicity. Using minoxidil as an initial template for structural modifications in conjunction with an in vitro neurite outgrowth assay, an image-based high-content screening platform, and mouse behavior models, an effective neuroprotective agent CN016 was discovered. Our results showed that CN016 could inhibit paclitaxel-induced inflammatory responses and infiltration of immune cells into sensory neurons significantly. Thus, the suppression of proinflammatory factors elucidates, in part, the mechanism of action of CN016 on alleviating paclitaxel-induced peripheral neuropathy. Based on excellent efficacy in improving behavioral functions, high safety profiles (MTD > 500 mg/kg), and a large therapeutic window (MTD/MED > 50) in mice, CN016 might have great potential to become a peripherally neuroprotective agent to prevent neurotoxicity caused by chemotherapeutics as typified by paclitaxel.