Effects of sterol derivatives in cationic liposomes on biodistribution and gene-knockdown in the lungs of mice systemically injected with siRNA lipoplexes

Abstract

Cationic liposomes can be intravenously injected to deliver short interfering (si)RNAs into the lungs. The present study investigated the effects of sterol derivatives in systemically injected siRNA/cationic liposome complexes (siRNA lipoplexes) on gene-knockdown in the lungs of mice. Cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane or dimethyldioctadecylammonium bromide (DDAB) were prepared as a cationic lipid, with sterol derivatives such as cholesterol (Chol), β-sitosterol, ergosterol (Ergo) or stigmasterol as a neutral helper lipid. Transfected liposomal formulations composed of DDAB/Chol or DDAB/Ergo did not suppress the expression of the luciferase gene in LLC-Luc and Colon 26-Luc cells in vitro, whereas other formulations induced moderate gene-silencing. The systemic injection of siRNA lipoplexes formulated with Chol or Ergo into mice resulted in abundant siRNA accumulation in the lungs. In comparison, systemically injected DDAB/Chol or DDAB/Ergo lipoplexes of Tie2 siRNA effectively increased the suppression of the Tie2 mRNA expression in the lungs of mice. These findings indicated that DDAB/Chol and DDAB/Ergo liposomes could function as vectors for siRNA delivery to the lungs.

Doxorubicin-loaded liposomes surface engineered with the matrix metalloproteinase-2 cleavable polyethylene glycol conjugate for cancer therapy

“…As compared to Caelyx ® , the accumulation of CLs containing the MMP-2 cleavable DOPE-peptide-PEG conjugate (F5 and F6) was significantly ( P < 0.0001) reduced in the kidney and heart while it was considerably more in the lung. This finding is consistent with earlier studies in which CLs exhibited substantial binding and accumulation in the pulmonary capillary bed as well as uptake by the macrophages in the liver and spleen (Hattori et al 2021 ; Samuelsson et al 2017 ). Thus, these CL formulations might have promising potential for treating lung malignancies in future.…”

In Cellulo and In Vivo Comparison of Cholesterol, Beta-Sitosterol and Dioleylphosphatidylethanolamine for Lipid Nanoparticle Formulation of mRNA

“…Oberli et al evidenced as well an induction of inflammation at the injection site after subcutaneous injection of DSPC-LNPs in 20% of mice and 0% of mice with DOPE-LNPs suggesting an impact of the helper lipid on immune cell activation/recruitment in vivo [ 33 ]. The findings reported are in accordance with those of Hattori et al on sterol derivatives for siRNA delivery in murine cancer cells and mice lungs [ 63 ]. They compared the silencing activities of lipoplexes made of DOTAP (1,2-dioleoyl-3-trimethylammonium-propane) and four different sterol derivatives: cholesterol, stigmasterol, ergosterol, and βS.…”

Optimal combination of cationic lipid and phospholipid in cationic liposomes for gene knockdown in breast cancer cells and mouse lung using siRNA lipoplexes

“…By contrast, DDAB-based cationic liposomes showed high in vivo gene knockdown efficacy when DDAB was combined with DOPE. Our recent study reported that cationic liposomes composed of DDAB and Chol induce high gene knockdown efficiency of Tie2 mRNA (>70%) when lipoplexes with 20 µg Tie2 siRNA are systemically injected into mice ( 13 ). DOTAP has unsaturated dialkyl chains (Tm, −12°C) ( 30 ) while DDAB has saturated dialkyl chains (Tm, 43°C) ( 31 ), indicating that combination of DOTAP and phospholipid may be unstable in blood circulation (37°C) following systemic injection, resulting in poor gene knockdown.…”

“…Erythrocyte suspension was prepared from whole blood of female BALB/c mice (age, 8 weeks; Sankyo Labo Service Corporation, Inc.), as previously described ( 13 ). siRNA lipoplexes with 2 µg siRNA were added to 100 µl 2% (v/v) erythrocyte suspension.…”

“…The most common cationic lipids for siRNA delivery with cationic liposomes are 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) ( 7 – 10 ), 1,2-di- O -octadecenyl-3-trimethylammonium-propane ( 10 – 12 ) and dimethyldioctadecylammonium bromide (DDAB) ( 9 , 13 ) which contain a quaternary ammonium group in the head group. 1,2-Dioleoyl- sn -glycero-3-phosphoethanolamine (DOPE), which has a small head group, is unsaturated and has long dialkyl chains; it is often used as a neutral helper lipid to prepare cationic liposome ( 7 – 12 ) because DOPE destabilizes siRNA lipoplexes in endosomes by inducing a change in conformation at acidic pH when incorporated into the liposomal formulation ( 14 ).…”