Critical contribution of macrophage scavenger receptor 1 to the uptake of nanostructured DNA by immune cells

Area of Science:

• Immunology
• Nanotechnology
• Molecular Biology

Background:

• Efficient uptake of nanostructured DNA (polypodna) by immune cells is known.
• The precise mechanism for polypodna uptake remains unclear.
• Previous work linked macrophage scavenger receptor 1 (MSR1) to tetrapod-like DNA uptake.

Purpose of the Study:

• To investigate the role of MSR1 in the structure-dependent uptake of polypodna.
• To elucidate the mechanism by which MSR1 interacts with nanostructured DNA.

Main Methods:

• Transfection of MSR1 in HEK-Blue hTLR9 cells to assess polypodna uptake.
• MSR1 knockout in RAW264.7 cells to evaluate uptake and cytokine release.
• Biochemical assays using cross-linking to examine MSR1-DNA binding.

Main Results:

• MSR1 transfection increased polypodna uptake in a pod number-dependent manner.
• MSR1 knockout reduced polypodna uptake and cytokine release in RAW264.7 cells.
• MSR1 directly binds to polypodna, but not single-stranded DNA, in immune cells.

Conclusions:

• MSR1 plays a key role in the efficient uptake of polypodna by immune cells.
• MSR1 exhibits selectivity, discriminating between nanostructured and simple DNA.
• This interaction is critical for cellular entry and subsequent immune responses to nanostructured DNA.