Protecting liver sinusoidal endothelial cells suppresses apoptosis in acute liver damage.

AIM: Apoptosis is associated with various types of hepatic disorders. We have developed a novel cell-transfer drug delivery system (DDS) using a multifunctional envelope-type nano device that targets liver sinusoidal endothelial cells (LSECs). The purpose of this study was to determine the efficacy of the novel DDS containing siRNA at suppressing apoptosis in LSECs. METHODS: Bax siRNA was transfected into a sinusoidal endothelial cell line (M1) to suppress apoptosis induced by an anti-Fas antibody and staurosporine. C57BL/6J mice were divided into three groups: (i) a control group, only intravenous saline; (ii) a nonselective group, injections of siRNA sealed in the nonselective DDS; and (iii) an LSEC-transfer efficient group, injections of siRNA sealed in an LSEC-transfer efficient DDS. Hepatic cell apoptosis was induced by an anti-Fas antibody. RESULTS: Bax siRNA had an anti-apoptotic effect on M1 cells. Serum alanine aminotransferase was reduced in the LSEC-transfer efficient group, as were cleaved caspase-3 and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling positive hepatocytes. Silver impregnation staining indicated that the sinusoidal space was maintained in the LSEC-transfer efficient group but not in the other groups. Electron microscopy showed that the LSECs were slightly impaired, although the sinusoidal structure was maintained in the LSEC-transfer efficient group. CONCLUSION: Hepatocyte apoptosis was reduced by the efficient suppression of LSEC apoptosis with a novel DDS. Protecting the sinusoidal structure by suppressing LSEC damage will be an effective treatment for acute liver failure.

Ligand density at the surface of a nanoparticle and different uptake mechanism: two important factors for successful siRNA delivery to liver endothelial cells.

The specific delivery of a gene to liver sinusoidal endothelial cells (LSEC) could become a useful strategy for treating various liver diseases associated with such cells. We previously reported that the accumulation of KLGR peptide modified liposomes through liver sinusoidal blood vessels was enhanced after an intravenous administration. Here, we report on an attempt to develop an LSEC targeted nanocarrier system to deliver siRNA for the successful knockdown of LSEC specific gene expression. The system involved the development of a multifunctional envelop-type nano device (MEND) modified with the KLGR peptide for siRNA delivery targeting LSEC. Our developed carrier successfully lowered specific gene expression in LSEC. An in vivo study showed that at a lower density of ligand at the surface of the MEND resulted in the highest knockdown of gene expression in LSEC. This is the first report of the successful delivery of siRNA to LSECs. Further experiments suggest that not only a higher endosomal escape efficiency into the cytosol but also the uptake mechanism as a function of ligand density are two important factors to be considered for targeting LSEC.

Hepatic Monoacylglycerol O-acyltransferase 1 as a Promising Therapeutic Target for Steatosis, Obesity, and Type 2 Diabetes.

Over the past decade, considerable advances have been made in the discovery of gene targets in metabolic diseases. However, in vivo studies based on molecular biological technologies such as the generation of knockout mice and the construction of short hairpin RNA vectors require considerable effort and time, which is a major limitation for in vivo functional analysis. Here, we introduce a liver-specific nonviral small interfering RNA (siRNA) delivery system into rapid and efficient characterization of hepatic gene targets in metabolic disease mice. The comparative transcriptome analysis in liver between KKAy diabetic and normal control mice demonstrated that the expression of monoacylglycerol O-acyltransferase 1 (Mogat1), an enzyme involved in triglyceride synthesis and storage, was highly elevated during the disease progression. The upregulation of Mogat1 expression in liver was also found in other genetic (db/db) and diet-induced obese mice. The silencing of hepatic Mogat1 via a liver-specific siRNA delivery system resulted in a dramatic improvement in blood glucose levels and hepatic steatosis as well as overweight with no apparent overall toxicities, indicating that hepatic Mogat1 is a promising therapeutic target for metabolic diseases. The integrated approach with transcriptomics and nonviral siRNA delivery system provides a blueprint for rapid drug discovery and development.

Animal husbandry practices in rural Bangladesh: potential risk factors for antimicrobial drug resistance and emerging diseases.

Antimicrobial drug administration to household livestock may put humans and animals at risk for acquisition of antimicrobial drug-resistant pathogens. To describe animal husbandry practices, including animal healthcare-seeking and antimicrobial drug use in rural Bangladesh, we conducted semi-structured in-depth interviews with key informants, including female household members (n = 79), village doctors (n = 10), and pharmaceutical representatives, veterinarians, and government officials (n = 27), and performed observations at animal health clinics (n = 3). Prevalent animal husbandry practices that may put persons at risk for acquisition of pathogens included shared housing and water for animals and humans, antimicrobial drug use for humans and animals, and crowding. Household members reported seeking human and animal healthcare from unlicensed village doctors rather than formal-sector healthcare providers and cited cost and convenience as reasons. Five times more per household was spent on animal than on human healthcare. Strengthening animal and human disease surveillance systems should be continued. Interventions are recommended to provide vulnerable populations with a means of protecting their livelihood and health.

A liposomal delivery system that targets liver endothelial cells based on a new peptide motif present in the ApoB-100 sequence.

Liver dysfunction is associated with a variety of liver diseases, including viral or alcoholic hepatitis, fibrosis, cirrhosis, and portal hypertension. A targeted drug delivery system would be very useful in the treatment of these diseases. We herein describe the development of a system comprised of a new peptide-lipid conjugate for the efficient delivery of molecules to LEC. The RLTRKRGLK sequence (3359-3367), which mediates the association of LDL with arterial CSPG and an LDL receptor, was utilized as a ligand for achieving this goal. The peptide modified PEG-LPs (RLTR-PEG-LPs) were efficiently taken up by primary liver endothelial cells (liver ECs) and other types of cells. In vivo biodistribution and confocal microscopy analysis showed that RLTR-PEG-LPs became widely accumulated in LECs within a short time. Distribution of RLTR-PEG-LPs was greatly reduced with a pretreatment of unlabeled RLTR-PEG-LPs, not cationic LPs, indicating that the sequence is important for LECs. The findings indicate that a reverse sequence of RLTR (KLGR) modified PEG-LPs (KLGR-PEG-LP) did the same pattern compared with RLTR-PEG-LPs, suggesting that the RKR or RXXR sequence might be essential for LECs targeting. Collectively RLTR-PEG-LPs and KLGR-PEG-LPs have the potential for delivering drugs to LECs.