Innovative and Efficient Oral Delivery Method of APOA-1Milano Muteins Which Retain Anti-Atherosclerotic and Anti-Inflammatory Properties

Background. The management of modifiable risk factors exposure, in particular dyslipidemia, is the first line of intervention in preventing cardiovascular events. HDLs have been demonstrated to have anti-inflammatory and atheroprotective properties and, among HDLs, Apolipoprotein A-I (APOA-1), which promotes reverse cholesterol efflux, has been deeply investigated for the great therapeutic potential, particularly emphasized for the naturally occurring mutation APOA-1Milano (APOA-1M). Despite the high therapeutic potential of these molecules, their purification and delivery into the disordered organism is still limited by a very low efficiency in these processes. Aim. To develop an efficient system of production and delivery of APOA-1 muteins without need of purification. Methods and Results. Rice plants were genetically modified to express APOA-1M protein in their seeds. Protein extract from transgenic rice seeds (the ‘APOA-1M rice milk’) was tested for functionality in vitro on THP-1 macrophages exposed to oxLDL. Protein extract from wild type rice seeds (the ‘WT rice milk’) was used as control. The APOA-1M rice milk, but not the WT rice milk, significantly reduced expression of MCP-1 in oxLDL-loaded THP-1 macrophages in a dose-dependent manner and it promoted reverse cholesterol efflux in THP-1 macrophages. The lack of toxicity and the tolerability of the orally administered APOA-1M rice milk was evaluated in healthy mice. In an early-intermediate atherosclerotic mouse model (Apoe-/-mice fed with Western Diet for 8 weeks), 3 weeks of APOA-1M, but not the WT, rice milk treatment (15d, 5d/week, by oral gavage) significantly reduced area of lipid deposition and lipids concentration at aortic arch (en face analysis). Moreover, the APOA-1M, but not the WT, rice milk treatment reduced the hepatic CD68-positive cells and ameliorated the lipid management gene expression profile in liver of WD-fed Apoe-/-mice. Interestingly, all these findings were observed in mice still exposed to WD during the therapeutic treatment. Conclusion. The oral delivery of APOA-1M muteins, by means of genetically modified rice seeds extract, is athero-protective and anti-inflammatory even if the organism is exposed to high fat diet during the treatment, suggesting that this therapeutic approach could be effective in preventing and in counteracting atherogenic risk factors.