ABSTRACT
RNA interference (RNAi) is a gene-silencing mechanism triggered by the cytosolic entry of double-stranded RNAs (dsRNAs). Many animal cells internalize extracellular dsRNAs via endocytosis for RNAi induction. However, it is not clear how the endocytosed dsRNAs are translocated into the cytosol across the endo/lysosomal membrane. Herein, we show that in Drosophila S2 cells, endocytosed dsRNAs induce lysosomal membrane permeabilization (LMP) that allows cytosolic dsRNA translocation. LMP mediated by dsRNAs requires the lysosomal Cl-/H+ antiporter ClC-b/DmOstm1. In clc-b or dmostm1 knockout S2 cells, extracellular dsRNAs are endocytosed and reach the lysosomes normally but fail to enter the cytosol. Pharmacological induction of LMP restores extracellular dsRNA-directed RNAi in clc-b or dmostm1-knockout cells. Furthermore, clc-b or dmostm1 mutant flies are defective in extracellular dsRNA-directed RNAi and its associated antiviral immunity. Therefore, endocytosed dsRNAs have an intrinsic ability to induce ClC-b/DmOstm1-dependent LMP that allows cytosolic dsRNA translocation for RNAi responses in Drosophila cells.
Subject(s)
Cytosol , Drosophila Proteins , Endocytosis , Lysosomes , RNA Interference , RNA, Double-Stranded , Animals , RNA, Double-Stranded/metabolism , Lysosomes/metabolism , Cytosol/metabolism , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Drosophila melanogaster/metabolism , Drosophila melanogaster/genetics , Chloride Channels/metabolism , Chloride Channels/genetics , Cell Line , Intracellular Membranes/metabolism , Permeability , Drosophila/metabolism , Drosophila/geneticsABSTRACT
With the approval for use in foods in Japan and the United States, the use of diacylglycerol (DAG) oil in fat-based products may become extensive due to equivalent physicochemical properties to conventional triacylglycerol (TAG) oil. The objective of the present study was to compare the effects of high-dose consumption of DAG oil in humans with that of TAG oil. In a double-blind controlled parallel trial, moderately lean men (n=42) and women (n=39) consumed either DAG or TAG at a dose of approximately 0.5 g/kg body weight/day as part of their diet for 12 weeks. All subjects completing the study tolerated the test oils well and showed no overt effects. Total caloric and fat intake remained constant and showed no significant differences between the groups. There was no significant difference in the occurrence of clinical signs and physical complaints related to test oil consumption. Although some statistically significant effects were reported in hematological and serum chemistry parameters in both DAG and TAG groups, none of these reported changes were considered biologically significant. Overall, this 12-week clinical study revealed no significant or treatment-related adverse effects of DAG oil consumed at a dose of 0.5 g/kg of body weight/day as part of the diet.