Phosphaditylserine liposomes as a possible candidate for the therapeutic management of Mycobacterium abscessus infection in CF patients

Introduction: we have previously reported that phosphatidylserine liposome (PS-L) were capable to induce a significant antimycobacterial response in mycobacterium tuberculosis (MTB)-infected and MTB/HIV-1-coinfected macrophages by simultaneously limiting inflammatory response and HIV replication. Here, we have assessed the therapeutic value of PS-L on human macrophages in vitro infected with M. abscessus (Mab), a non-tubercular mycobacterium which represents a relevant cause of morbidity and mortality in vulnerable patients such as those with cystic fibrosis (CF). Materials and methods: Differentiated THP-1 cells (dTHP-1), used as a model of human macrophages, and primary macrophages derived from CF patients, were in vitro infected with Mab and then stimulated or not PS-L. the therapeutic value of the treatment was assessed in terms of intracellular mycobacterial viability, by CFU assay, and NF-kB activation (calculated as the ratio between total NF-κB and phosphorylated NF-κB) by NFκB p65 (Total/Phospho) Human InstantOne™ ELISA Kit (Invitrogen) results: results show that in vitro stimulation with PS-L of dTHP-1 cells in vitro infected with mab significantly reduces intracellular mycobacterial viability and was associated with a significant drop in NF-κB activation. Importantly, such pro-mycobacteriocidal effect was also observed on macrophages from cystic fibrosis patients in vitro infected with Mab. discussion and conclusions: altogether, these results extend our previously reported results obtained on MTB-infected and MTB/HIV-coinfected cells, also against a relevant difficult-to-treat non tubercular mycobacterium, such as Mab, and support the therapeutic exploitation of PS-L as host-directed therapy to simultaneously limit potentially pathogenetic proinflammatory response and intracellular Mab viability in vulnerable patients, such as CF patients.