The malaria parasite, Plasmodium falciparum, displays the P. falciparum erythrocyte membrane protein 1 (PfEMP1) on the surface of infected red blood cells (RBCs). We here examine the physical organization of PfEMP1 trafficking intermediates in infected RBCs and determine interacting partners using an epitope-tagged minimal construct (PfEMP1B). We show that parasitophorous vacuole (PV)-located PfEMP1B interacts with components of the PTEX (Plasmodium Translocon of EXported proteins) as well as a novel protein complex, EPIC (Exported Protein-Interacting Complex). Within the RBC cytoplasm PfEMP1B interacts with components of the Maurer’s clefts and the RBC chaperonin complex. We define the EPIC interactome and, using an inducible knockdown approach, show that depletion of one of its components, the parasitophorous vacuolar protein-1 (PV1), results in altered knob morphology, reduced cell rigidity and decreased binding to CD36. Accordingly, we show that deletion of the Plasmodium berghei homologue of PV1 is associated with attenuation of parasite virulence in vivo.

SUMMARY Liver fibrosis, a form of scarring, gradually develops in chronic liver diseases when hepatocyte regeneration cannot compensate for hepatocyte death. At earlier stages, collagen produced by activated myofibroblasts (MFs) functions to maintain tissue integrity, but upon repeated injury, collagen accumulation suppresses hepatocyte regeneration, ultimately leading to liver failure. As a strategy to generate new hepatocytes and limit collagen deposition in the chronically injured liver, we developed in vivo reprogramming of MFs into hepatocytes using adeno-associated virus (AAV) vectors expressing hepatic transcription factors. We first identified the AAV6 subtype as effective in transducing MFs in mouse models of chronic liver disease. We then use lineage-tracing approaches to show that hepatocytes reprogrammed from MFs replicate primary hepatocyte function, and that liver fibrosis in AAV treated animals is reduced. Because AAV vectors are already used for liver-directed human gene therapy, our strategy has potential for clinical translation into a therapy for liver fibrosis.

Actively contractile cardiomyocyte (CM) monolayer represents an interesting tool to study both cardiac diseases and injuries. However, this model is poorly transfectable with conventional agents. Consequently, there is a need to develop new carriers that could overcome this problem. Titanate nanotubes (TiONts) could be a potential candidate due to possibly higher cell uptake as a direct consequence of their shape. On the basis of this rationale, TiONts were assessed for their cytotoxicity and internalization pathways. Cytotoxicity was assessed for TiONts either functionalized with PEI or unfunctionalized and its spherical counterpart P25 TiO2. No cytotoxic effect was observed under TiONts, TiONts-PEI1800 and P25 TiO2 exposed conditions. The tubular morphology was found to be an important parameter promoting internalization while reversing the charge was assessed as non-additional. Internalization was found to occur by endocytosis and diffusion through the membrane. A preliminary transfection study indicated the potential of TiONts as a nanocarrier.

Transgenic mice expressing human cholesteryl ester transfer protein (HuCETPTg mice) were crossed with apolipoprotein CI-knocked out (apoCI-KO) mice. Although total cholesterol levels tended to be reduced as the result of CETP expression in HuCETPTg heterozygotes compared with C57BL6 control mice (؊13%, not significant), a more pronounced decrease (؊28%, p < 0.05) was observed when human CETP was expressed in an apoCI-deficient background (HuCETPTg/apoCI-KO mice). Gel permeation chromatography analysis revealed a significant, 6.1-fold rise (p < 0.05) in the cholesteryl ester content of very low density lipoproteins in HuCETPTg/apoCI-KO mice compared with control mice, whereas the 2.7-fold increase in HuCETPTg mice did not reach the significance level in these experiments. Approximately 50% decreases in the cholesteryl ester content and cholesteryl ester to triglyceride ratio of high density lipoproteins (HDL) were observed in HuCETPTg/apoCI-KO mice compared with controls (p < 0.05 in both cases), with intermediate ؊20% changes in HuCETPTg mice. The cholesteryl ester depletion of HDL was accompanied with a significant reduction in their mean apparent diameter (8.68 ؎ 0.04 nm in HuCETPTg/apoCI-KO mice versus 8.83 ؎ 0.02 nm in control mice; p < 0.05), again with intermediate values in HuCETPTg mice (8.77 ؎ 0.04 nm). In vitro purified apoCI was able to inhibit cholesteryl ester exchange when added to either total plasma or reconstituted HDL-free mixtures, and coincidently, the specific activity of CETP was significantly increased in the apoCI-deficient state (173 ؎ 75 pmol/g/h in HuCETPTg/apoCI-KO mice versus 72 ؎ 19 pmol/g/h in HuCETPTg, p < 0.05). Finally, HDL from apoCI-KO mice were shown to interact more readily with purified CETP than control HDL that differ only by their apoCI content. Overall, the present observations provide direct support for a potent specific inhibition of CETP by plasma apoCI in vivo.