Peptidomimetic Lipid-Nanoparticle-Mediated Knockdown of TLR4 in CNS Protects against Cerebral Ischemia/Reperfusion Injury in Mice

Abstract

Ischemic stroke activates toll-like receptor 4 (TLR4) signaling, resulting in proinflammatory polarization of microglia and secondary neuronal damage. Herein, we report a novel lipid-nanoparticle (LNP)-mediated knockdown of TLR4 in microglia and amelioration of neuroinflammation in a mouse model of transient middle cerebral artery occlusion (tMCAO). siRNA against TLR4 (siTLR4) complexed to the novel LNP (siTLR4/DoGo310), which was based on a dioleoyl-conjugated short peptidomimetic (denote DoGo310), was readily internalized by the oxygen–glucose-deprived (OGD) mouse primary microglia, knocked-down TLR4, and polarized the cell to the anti-inflammatory phenotype in vitro. Systemic administration of siTLR4/DoGo310 LNPs in the tMCAO mice model resulted in the accumulation of siRNA mainly in the Iba1 positive cells in the peri-infarct. Analysis of the peri-infarct brain tissue revealed that a single injection of siTLR4/DoGo310 LNPs led to significant knockdown of TLR4 gene expression, reversing the pattern of cytokines expression, and improving the neurological functions in tMCAO model mice. Our data demonstrate that DoGo310 LNPs could be a promising nanocarrier for CNS-targeted siRNA delivery for the treatment of CNS disorders.

Injectable Amphipathic Artesunate Prodrug‐Hydrogel Microsphere as Gene/Drug Nano‐Microplex for Rheumatoid Arthritis Therapy

“…Finally, diluted TNF‐α siRNA (Beyotime Biotechnology Co., Nantong, China) with preset weight ratios (0–4%) was added to dACC/dAPC‐DSPE‐PEG‐FA lipoplex suspension, and the lipoplex was obtained by slight shaking and left to stand still for 30 min at 37 °C. [ 54 ]…”

“…Finally, diluted TNF-α siRNA (Beyotime Biotechnology Co., Nantong, China) with preset weight ratios (0-4%) was added to dACC/dAPC-DSPE-PEG-FA lipoplex suspension, and the lipoplex was obtained by slight shaking and left to stand still for 30 min at 37 °C. [54] The particle sizes and zeta potentials of TNF-α siRNA loaded dACC/ dAPC-DSPE-PEG-FA lipoplexes with different siRNA weight ratios were measured by a particle size analyzer (Malvern Instruments Ltd., Malvern, UK). The siRNA binding capacity of TNF-α siRNA-loaded dACC/dAPC-DSPE-PEG-FA lipoplex was investigated by 1% agarose gel (Beyotime Biotechnology Co., Nantong, China) electrophoresis.…”

Role of microglia in stroke

“…Accordingly, strategies designed to downregulate TLR-4 expression in microglia attenuated brain inflammation and reduced the extent of the brain lesion in a murine model of tMCAo (Ganbold et al, 2022).…”

“…Detrimental effects in brain ischemia Caso et al, 2007;Lehnardt et al, 2008;Kilic et al, 2008;Hua et al, 2009;Ganbold et al, 2022;Janova et al, 2016 Involvement of neutrophils in the negative effect of TLR4…”

Nanotechnology in Stroke: New Trails with Smaller Scales

“…For example, the liposomal cyclosporine A [ 128 ] and berberine nano micelles [ 129 ] have been reported to reduce microglial immunoreactivity, inflammatory responses, and infarct lesion volumes. Nanoparticles conjugated with monocyte membrane and rapamycin have been shown to inhibit the proliferation of neutrophils [ 130 ], reversing the pattern of inflammatory cytokines expression, resulting in improved neurological function [ 131 ]. In a few instances, the compound has pleiotropic effects.…”