Abstract
Scavenger receptors clear pathogens, transport lipid, and mediate polyanionic ligand uptake in macrophages, but their expression and role in the skin are poorly understood. Although the epidermal barrier typically excludes nucleic acid entry, topically applied, spherically arranged oligonucleotide nanoconjugates (spherical nucleic acids [SNAs]) penetrate mouse skin, three-dimensional (3D) skin equivalents, and human skin. We explored the mechanism of SNA uptake in normal human epidermal keratinocytes and 3D skin equivalents. Normal human epidermal keratinocytes and 3D raft treatment with SR-A inhibitors reduced SNA uptake by >80%. The human epidermis expresses SR-As SCARA3 and, to a lesser extent, MARCO. Simultaneous lentiviral knockdown of SCARA3 and MARCO reduced SNA uptake in normal human epidermal keratinocytes and 3D rafts after topical application, affirming a role for SR-As in SNA uptake and 3D raft penetration. Incubation of normal human epidermal keratinocytes at 4oC or with sodium azide prevented SNA uptake, suggesting active endocytosis. Endocytosis inhibitors, immunofluorescence, immunoprecipitation, and knockdown studies localized functional SR-As to FLOT-1-containing lipid rafts throughout the epidermis and CAV-1-containing rafts only in the upper epidermis. These studies suggest a central role for SR-A complexes in epidermal lipid rafts in mediating the uptake of nucleic acid‒laden nanoparticles.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1428-1437.e8 |
| Journal | Journal of Investigative Dermatology |
| Volume | 141 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2021 |
Funding
We acknowledge the contributions of Andrew Lee, Robert Stawicki, and Shengshuang Zhu in making nanoparticles. This research was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases R01AR060810 (AP and CM), National Institute of Arthritis and Musculoskeletal and Skin Diseases R01AR068375 (AP), and National Cancer Institute U54CA199091 (CM). The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. This research was also sponsored by Air Force Research Laboratory under agreement FA8650-15-2-5518. The United States Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright notation thereon. The views and conclusions contained in this paper are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of Air Force Research Laboratory or the United States Government. Core resources were provided by the Northwestern University (Chicago, IL) Skin Biology and Diseases Resource-based Center (National Institute of Arthritis and Musculoskeletal and Skin Diseases P30 AR057216 and P30 AR075049) and the Northwestern University Center for Advanced Microscopy (National Cancer Institute CCSG P30 CA060553). Metal analysis was performed at the Northwestern University Quantitative Bio-element Imaging Center and was funded by the Chicago Biomedical Consortium, National Institutes of Health under award number S10OD020118. Scanning Transmission electron microscopy was performed at the Electron Probe Instrumentation Center facility of Northwestern University's Northwestern University Atomic and Nanoscale Characterization Experimental Center funded by Soft and Hybrid Nanotechnology Experimental Resource (NSF ECCS-1542205), the Materials Research Science and Engineering Centers program (NSF DMR-1121262) at the Materials Research Center, the International Institute for Nanotechnology, the Keck Foundation, and the State of Illinois, through the International Institute for Nanotechnology. CM gratefully acknowledges support from the Nanyang Technological University‒Northwestern University Institute for NanoMedicine located at the International Institute for Nanotechnology, Northwestern University and the Nanyang Technological University (Singapore). QS, TRH, MB, and ASP had full access to all data and take responsibility for data integrity and the accuracy of data and analysis. Conceptualization: QS, ASP; Data Curation: QS, XQW, TRH, MB, EWR, CM, ASP, AP; Formal Analysis: QS, TRH, MB; Project Administration: QS, XQW, TRH, MB, EWR, CM, ASP, AP; Supervision: ASP; Writing – Original Draft Preparation: QS; Writing – Review and Editing: QS, XQW, TRH, MB, EWR, CM, ASP, AP
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Dermatology
- Cell Biology