Intranasal Administration of N-acetyl-L-cysteine Combined with Cell-Penetrating Peptide-Modified Polymer Nanomicelles as a Potential Therapeutic Approach for Amyotrophic Lateral Sclerosis.

Intranasal administration is a promising route for direct drug delivery to the brain; its combination with nanocarriers enhances delivery. We have previously shown that intranasal administration combined with PEG-PCL-Tat (a nanocarrier) efficiently delivers drugs to the brain and exhibits excellent therapeutic efficacy against brain diseases. We aimed to clarify whether intranasal administration combined with PEG-PCL-Tat represents a useful drug delivery system (DDS) for amyotrophic lateral sclerosis (ALS) pharmacotherapy. We used N-acetyl-L-cysteine (NAC) as a model drug with low transferability to the spinal cord and determined the physicochemical properties of NAC/PEG-PCL-Tat. After intranasal administration of NAC/PEG-PCL-Tat, we measured the survival duration of superoxide dismutase-1 G93A mutant transgenic mice (G93A mice), widely used in ALS studies, and quantitatively analyzed the tissue distribution of NAC/PEG-PCL-Tat in ddY mice. The mean particle size and zeta potential of NAC/PEG-PCL-Tat were 294 nm and + 9.29 mV, respectively. Treatment with repeated intranasal administration of NAC/PEG-PCL-Tat considerably prolonged the median survival of G93A mice by 11.5 days compared with that of untreated G93A mice. Moreover, the highest distribution after a single administration of NAC/PEG-PCL-Tat was measured in the spinal cord. These results suggest that intranasal administration combined with PEG-PCL-Tat might represent a useful DDS for ALS therapeutics.

Increased Tropism of Extracellular Vesicles Derived from Palmitic Acid-Treated Hepatocytes to Activated Hepatic Stellate Cells.

Myofibroblast-like activated hepatic stellate cells (aHSCs), which produce collagen, a major cause of liver fibrosis, are specific target cells for antifibrotic treatment. Recently, several reports have indicated that extracellular vesicles (EVs) play important roles in cell-to-cell communication through their tropism for specific cells or organs. Therefore, the present study aimed to identify aHSC-directed EVs by focusing on cell-to-cell interactions in the liver under pathological conditions. EVs were derived from the hepatocyte cell line AML12 treated with or without palmitic acid (PA) and evaluated for their physical properties and uptake by the aHSC cell line LX-2. AML12-derived EVs had a mean particle diameter of 110-130 nm, negative charge, and expressed the exosomal makers CD9 and CD63. PA-treated AML12 cells released larger EVs with higher protein levels than those without PA treatment. The intracellular uptake efficacy of EVs derived from PA-treated AML12 cells into activated LX-2 cells was significantly higher than those without PA treatment. Our study revealed that PA treatment induces hepatocytes to release EVs with aHSC-tropism. These findings may contribute to the development of an EV-based drug delivery system (DDS) for aHSC-targeted therapy and provide new insights into the role of steatotic hepatocyte-derived EVs in physiological or pathophysiological functions.