Preliminary Characterization of Extracellular Vesicles From Auditory HEI-OC1 Cells.

Kalinec PhD GM1, Cohn BSc W2, Whitelegge PhD JP2, Faull PhD KF2, Kalinec PhD F1.

Author information

1

1 Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

2

2 Pasarow Mass Spectrometry Laboratory, Jane and Terry Semel Institute for Neuroscience and Human Behavior and Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

Abstract

OBJECTIVES:

Isolate, purify, and characterize extracellular vesicles (EVs) obtained from auditory HEI-OC1 cells, and evaluate their suitability for intracochlear transport and delivery of pharmacological drugs and/or pro-resolution mediators of acute inflammatory processes.

METHODS:

HEI-OC1 EVs were isolated and purified using the exoEasy Maxi Kit, and their size was evaluated by nanoparticle tracking techniques. Bottom-up proteomics of the EVs, either freshly obtained or stored for up to 4 months at -20°C, was performed by LC-ESI-MS/MS. LC-ESI-MS/MS-MRM was used to measure the loading of dexamethasone inside EVs following co-incubation at room temperature for 1 hour with and without 5 minutes sonication.

RESULTS:

Routinely, we were able to obtain purified fractions of >2 × 109 EVs/mL, with diameters varying between 50 and 800 nm. Bottom-up proteomics showed that among the most abundant EVs proteins, 19.2% were cytoplasmic, 17.2% were membrane localized, 12.3% were cytosolic, and 14.6% were nucleolar. No significant differences between fresh and stored EVs were detected. Importantly, co-incubation of HEI-OC1 EVs (1 × 108 EVs/mL) with dexamethasone (10 mM) resulted in the incorporation of 10.1 ± 1.9 nM dexamethasone per milliliter of EVs suspension.

CONCLUSIONS:

Altogether, the results suggest that EVs from HEI-OC1 cells could be advantageously used as biological nanocarriers for the delivery of specific molecules and pharmacological drugs into the inner ear.

KEYWORDS:

HEI-OC1 cells; drug nanocarriers; extracellular vesicles; intracochlear drug delivery; proteomics

PMID:

 

31092033

 

DOI:

 

10.1177/0003489419836226

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