Radioprotective effect of transferrin targeted citicoline liposomes

Abstract

The high level of expression of transferrin receptors (Tf-R) on the surface of endothelial cells of the blood-brain-barrier (BBB) had been widely utilized to deliver drugs to the brain. The primary aim of this study was to use transferrin receptor mediated endocytosis as a pathway for the rational development of holo-transferrin coupled liposomes for drug targeting to the brain. Citicoline is a neuroprotective agent used clinically to treat for instance Parkinson disease, stroke, Alzheimer's disease and brain ischemia. Citicoline does not readily cross the BBB because of its strong polar nature. Hence, citicoline was used as a model drug. (Citicoline liposomes have been prepared using dipalmitoylphosphatidylcholine (DPPC) or distearoylphosphatidylcholine (DSPC) by dry lipid film hydration-extrusion method). The effect of the use of liposomes composed of DPPC or DSPC on their citicoline encapsulation efficiency and their stability in vitro were studied. Transferrin was coupled to liposomes by a technique which involves the prevention of scavenging diferric iron atoms of transferrin. The coupling efficiency of transferrin to the liposomes was studied. In vitro evaluation of transferrin-coupled liposomes was performed for their radioprotective effect in radiation treated cell cultures. In this study, OVCAR-3 cells were used as a model cell type over-expressing the Tf-R and human umbilical vein endothelial cells (HUVEC) as BBB endothelial cell model. The average diameter of DPPC and DSPC liposomes were 138 +/- 6.3 and 79.0 +/- 3.2 nm, respectively. The citicoline encapsulation capacity of DPPC and DSPC liposomes was 81.8 +/- 12.8 and 54.9 +/- 0.04 microg/micromol of phospholipid, respectively. Liposomes prepared from DSPC showed relatively better stability than DPPC liposomes at 37 degrees C and in the presence of serum. Hence, DSPC liposomes were used for transferrin coupling and an average of 46-55 molecules of transferrin were present per liposome. Free citicoline has shown radioprotective effect at higher doses tested. Interestingly, encapsulation of citicoline in pegylated liposomes significantly improved the radioprotective effect by 4-fold compared to free citicoline in OVCAR-3 but not in HUVEC. Further, citicoline encapsulation in transferrin-coupled liposomes has significantly improved the radioprotective effect by approximately 8-fold in OVCAR-3 and 2-fold in HUVEC cells with respect to the free drug. This is likely due to the entry of citicoline into cells via transferrin receptor mediated endocytosis. In conclusion, our results suggest that low concentrations of citicoline encapsulated in transferrin-coupled liposomes could offer therapeutic benefit in treating stroke compared to free citicoline.

Targeting the transferrin receptor for brain drug delivery

“…One study even showed that TfR-targeted liposomes encapsulating plasmid DNA could be administrated to a pregnant mouse, cross the placental barrier and mediate gene expression in the developing brain of the fetus (Cornford et al, 2015). Furthermore, endogenous Tf was tested in several studies as a targeting molecule for liposome transport with a variety of therapeutic effects including improvement after stroke and brain injury (Omori et al, 2003;Suresh Reddy et al, 2006), increased brain uptake of HIV drugs (Prabhakar et al, 2011), tumor size reduction in GBM (Jhaveri et al, 2018;Lakkadwala and J. Singh, 2019;C. Liu et al, 2017;Salzano et al, 2016;Sonali et al, 2016b;Zheng et al, 2015), or general gene knockdown after siRNA delivery into the brain (Cardoso et al, 2010;2008).…”

Quantum dots and nanoparticles for photodynamic and radiation therapies of cancer

“…Such effect is considerably smaller in endothelial cells. However, free citicoline was found to be less radioprotective in the ovarian adenocarcinoma cells than in the endothelial cells [189]. Carbon nanoparticles also exhibit radioprotective effect.…”

Lipid Microcapsules Promoted Neural Stem Cell Survival in the Infarcted Area of Mice with Ischemic Stroke by Inducing Autophagy

“…Lipids, the main component of the cell membrane and brain tissue, may be an ideal material for the encapsulation of NSCs, which might be used to repair brain damage. In fact, lipids have been widely used as carriers to deliver agents to treat, for instance, stroke, Parkinson’s disease, and Alzheimer’s disease . They have even been used to encapsulate hemoglobin, which reduced the size of the cerebral infarct in the rat .…”

“…In fact, lipids have been widely used as carriers to deliver agents to treat, for instance, stroke, Parkinson's disease, and Alzheimer's disease. 46 They have even been used to encapsulate hemoglobin, which reduced the size of the cerebral infarct in the rat. 47 To our A primary goal of this study was to develop a novel lipid microcapsule that would provide structural support for transplanted cells to promote regeneration of the CNS after ischemic stroke.…”