Triplex forming oligonucleotides against type α1(I) collagen attenuates liver fibrosis induced by bile duct ligation

The Effects of Spironolactone in Preventing Bile Duct Ligation-induced Hepatitis in A Rat Model

Cholestasis is associated with the accumulation of bile acids and bilirubin in the hepatocytes and leads to liver injury. Pregnane X Receptor (PXR) coordinates protective hepatic responses to toxic stimuli, and this receptor was reported to stimulate bile secretion by increasing MRP2 expression. Since PXR activators were reported to be anti-inflammatory in the liver, PXR was proposed as a drug target for the treatment of chronic inflammatory liver diseases. We investigated the potential protective effect of spironolactone (SPL), an enzyme inducer, in hepatotoxicity induced by bile duct ligation in rats. Wistar Albino (250-300 g) rats were divided into the control group and the bile duct ligated (BDL) group. BDL group was divided into three subgroups; following BDL, for 3 days, the first group received propylene glycol (vehicle of SPL) (blinded), the second subgroup received spironolactone (SPL) (200 mg/kg oral), and the third subgroup received SPL for 3 days, starting 3 days after the bile duct ligation, in order to investigate if it has a healing effect after hepatitis had developed. The control group was sham-operated and received saline. At the end of the experiment, blood and tissue samples were collected. Serum TNF-α, NF-ĸB, bilirubin, IL-6 levels, ALT, AST, ALP activities and tissue MPO activity and oxidant damage increased after the bile duct ligation was significantly decreased following SPL administration. PXR and MRP2 activity showed an increase in the hepatocytes as a result of the treatment. In conclusion, it was observed that SPL administration significantly decreases liver inflammation and damage related to BDL.

Lipid based nanocarriers for effective drug delivery and treatment of diabetes associated liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a cluster of several liver diseases like hepatic steatosis, non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver (NAFL), liver fibrosis, and cirrhosis which may eventually progress to liver carcinoma. One of the primary key factors associated with the development and pathogenesis of NAFLD is diabetes mellitus. The present review emphasizes on diabetes-associated development of liver fibrosis and its treatment using different lipid nanoparticles such as stable nucleic acid lipid nanoparticles, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, self-nanoemulsifying drug delivery systems, and conjugates including phospholipid, fatty acid and steroid-based. We have comprehensively described the various pathological and molecular events linking effects of elevated free fatty acid levels, insulin resistance, and diabetes with the pathogenesis of liver fibrosis. Various passive and active targeting strategies explored for targeting hepatic stellate cells, a key target in liver fibrosis, have also been discussed in detail in this review.

CRISPR/Cas9 therapeutics for liver diseases

The development of innovative genome editing techniques in recent years has revolutionized the field of biomedicine. Among the novel approaches, the clustered regularly interspaced short palindromic repeat/CRISPR-associated protein (CRISPR/Cas9) technology has become the most popular, in part due to its matchless ability to carry out gene editing at the target site with great precision. With considerable successes in animal and preclinical studies, CRISPR/Cas9-mediated gene editing has paved the way for its use in human trials, including patients with a variety of liver diseases. Gene editing is a logical therapeutic approach for liver diseases because many metabolic and acquired disorders are caused by mutations within a single gene. In this review, we provide an overview on current and emerging therapeutic strategies for the treatment of liver diseases using the CRISPR/Cas9 technology.

Delivery and targeting of miRNAs for treating liver fibrosis

Liver fibrosis is a pathological condition originating from liver damage that leads to excess accumulation of extracellular matrix (ECM) proteins in the liver. Viral infection, chronic injury, local inflammatory responses and oxidative stress are the major factors contributing to the onset and progression of liver fibrosis. Multiple cell types and various growth factors and inflammatory cytokines are involved in the induction and progression of this disease. Various strategies currently being tried to attenuate liver fibrosis include the inhibition of HSC activation or induction of their apoptosis, reduction of collagen production and deposition, decrease in inflammation, and liver transplantation. Liver fibrosis treatment approaches are mainly based on small drug molecules, antibodies, oligonucleotides (ODNs), siRNA and miRNAs. MicroRNAs (miRNA or miR) are endogenous noncoding RNA of ~22 nucleotides that regulate gene expression at post transcription level. There are several miRNAs having aberrant expressions and play a key role in the pathogenesis of liver fibrosis. Single miRNA can target multiple mRNAs, and we can predict its targets based on seed region pairing, thermodynamic stability of pairing and species conservation. For in vivo delivery, we need some additional chemical modification in their structure, and suitable delivery systems like micelles, liposomes and conjugation with targeting or stabilizing the moiety. Here, we discuss the role of miRNAs in fibrogenesis and current approaches of utilizing these miRNAs for treating liver fibrosis.

In vitro antiviral activity of circular triple helix forming oligonucleotide RNA towards Feline Infectious Peritonitis virus replication

Feline Infectious Peritonitis (FIP) is a severe fatal immune-augmented disease in cat population. It is caused by FIP virus (FIPV), a virulent mutant strain of Feline Enteric Coronavirus (FECV). Current treatments and prophylactics are not effective. The in vitro antiviral properties of five circular Triple-Helix Forming Oligonucleotide (TFO) RNAs (TFO1 to TFO5), which target the different regions of virulent feline coronavirus (FCoV) strain FIPV WSU 79-1146 genome, were tested in FIPV-infected Crandell-Rees Feline Kidney (CRFK) cells. RT-qPCR results showed that the circular TFO RNAs, except TFO2, inhibit FIPV replication, where the viral genome copy numbers decreased significantly by 5-fold log₁₀ from 10¹⁴ in the virus-inoculated cells to 10⁹ in the circular TFO RNAs-transfected cells. Furthermore, the binding of the circular TFO RNA with the targeted viral genome segment was also confirmed using electrophoretic mobility shift assay. The strength of binding kinetics between the TFO RNAs and their target regions was demonstrated by NanoITC assay. In conclusion, the circular TFOs have the potential to be further developed as antiviral agents against FIPV infection.

Nanomedicines of Hedgehog inhibitor and PPAR-γ agonist for treating liver fibrosis

PURPOSE

Hedgehog (Hh) and peroxisome proliferator-activated receptor gamma (PPAR-γ) are major signaling pathways involved in the pathogenesis of liver fibrosis. Since Hh inhibitor, vismodegib (GDC) and PPAR-γ agonist, rosiglitazone (RSG) have poor water solubility, our objective was to formulate biodegradable polymeric nanoparticles encapsulating GDC and RSG for treating liver fibrosis.

METHODS

Methoxy-polyethylene-glycol-b-poly(carbonate-co-lactide) [mPEG-b-p(CB-co-LA)] was synthesized and characterized using (1)H NMR. Nanoparticles were prepared using this polymer by emulsification/solvent evaporation method to encapsulate GDC and RSG either alone or in combination. Nanoparticles were characterized for particle size, drug loading, drug release, and anti-fibrotic efficacy after tail vein injection into common bile duct ligated (CBDL) fibrotic rats.

RESULTS

mPEG-b-p(CB-co-LA) copolymer has molecular weight of 30,000 Da as determined by (1)H NMR. Nanoparticles were monodisperse with a mean particle size of 120-130 nm. Drug loading was 5% and 2% w/w for GDC and RSG, respectively. Nanoparticles carrying both GDC and RSG were formulated at half of their individual drug loading. Systemic administration of drug loaded nanoparticles protected liver injury in CBDL rats by suppressing the activation of hepatic stellate cells, and decreasing inflammatory cytokines.

CONCLUSION

Polymeric nanoparticles for co-delivery of Hh inhibitor and PPAR-γ agonist have the potential to treat liver fibrosis by intervening complex fibrotic cascade.

CGX, a multiple herbal drug, improves cholestatic liver fibrosis in a bile duct ligation-induced rat model

ETHNOPHARMACOLOGIC RELEVANCE

CGX is a modification of a traditional herbal medicine that has been used for various liver disorders as a meaning of "cleaning the liver". The cholestatic liver disorders become prevalent. BACK GROUND AND AIM: This study aimed to investigate the anti-hepatic fibrosis effects of CGX and its underlying mechanisms in a rat model of bile duct ligation (BDL).

MATERIALS AND METHODS

BDL was conducted in SD rats except shame operation group. The rats were orally administrated with distilled water, CGX (25 or 50 mg/kg) or ursodeoxycholic acid (UDCA, 25 mg/kg) for two weeks. The pharmaceutical effects and mechanisms were analyzed in histopathology, biochemistry, oxidative stress/antioxidant biomarkers and hepatic fibrogenic cytokines levels.

RESULTS

BDL markedly elevated white blood cell (WBC) counts as well as changed subset proportions such as increased neutrophils and decreased lymphocytes in peripheral blood. BDL drastically elevated the serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin, and hepatic tissue levels of hydroxyproline and malondialdehyde (MDA), while it reduced the total glutathione (GSH) content and the activities of GSH-redox system enzymes such as GSH-peroxidase, GSH-reductase and GSH-S-transferase. These alterations were significantly attenuated by CGX treatment (mainly 50 mg/kg). CGX treatment normalized both the accumulation of collagen in hepatic tissue and the increased levels of profibrogenic cytokine including transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor-BB (PDGF-BB). Moreover, CGX treatment enhanced interferon-gamma (IFN-γ) expression compare to the BDL group at the protein and gene level.

CONCLUSION

These results suggest that CGX exerts anti-hepatofibrotic effect in rat BDL model, and the responsible mechanisms involve the inhibition of hepatic fibrogenic cytokines and oxidative stress.

Attenuation of early liver fibrosis by pharmacological inhibition of smoothened receptor signaling

Hedgehog (Hh) signaling is involved in the pathogenesis of liver fibrosis. It has been previously shown that Hh-inhibitor cyclopamine (CYA) can reduce liver fibrosis in rats. However, CYA is not stable in vivo, which limits its clinical application. This study compares the antifibrotic potential of two known Hh antagonists, vismodegib (GDC-0449, abbreviated to GDC) and CYA. GDC is a synthetic molecule presently in clinical cancer trials and has been reported to be safe and efficacious. These drugs attenuated early liver fibrosis in common bile duct ligated rats, improved liver function, and prevented hepatic stellate cell (HSC) activation, thereby suppressing epithelial to mesenchymal transition (EMT). While both CYA and GDC increased the number of proliferating cell nuclear antigen positive liver cells in vivo, only CYA increased Caspase-3 expression in HSCs in rat livers, suggesting that while GDC and CYA effectively attenuate early liver fibrosis, their hepatoprotective effects may be mediated through different modes of action. Thus, GDC has the potential to serve as a new therapeutic agent for treating early liver fibrosis.

Conjugation of a 3-(1H-phenanthro[9,10-d]imidazol-2-yl)-1H-indole intercalator to a triplex oligonucleotide and to a three-way junction

A new intercalating nucleic acid monomer M comprising a 4-(1-indole)-butane-1,2-diol moiety was synthesized via a classical alkylation reaction of indole-3-carboxaldehyde followed by a condensation reaction with phenanthrene-9,10-dione in the presence of ammonium acetate to form a phenanthroimidazole moiety linked to the indole ring. Insertion of the new intercalator as a bulge into a Triplex Forming Oligonucleotide resulted in good thermal stability of the corresponding Hoogsteen-type triplexes. Molecular modeling supports the possible intercalating ability of M. Hybridisation properties of DNA/DNA and RNA/DNA three-way junctions (TWJ) with M in the branching point were also evaluated by their thermal stability at pH 7. DNA/DNA TWJ showed increase in thermal stability compared to wild type oligonucleotides whereas this was not the case for RNA/DNA TWJ.

Targeted TFO delivery to hepatic stellate cells

Triplex-forming oligonucleotides (TFOs) represent an antigene approach for gene regulation through direct interaction with genomic DNA. While this strategy holds great promise owing to the fact that only two alleles need silencing to impact gene regulation, delivering TFOs to target cells in vivo is still a challenge. Our recent efforts have focused on conjugating TFOs to carrier molecules like cholesterol to enhance their cellular uptake and mannose-6-phosphate-bovine serum albumin (M6P-BSA) to target TFO delivery to hepatic stellate cells (HSCs) for treating liver fibrosis. These approaches however are rendered less effective owing to a lack of targeted delivery, as seen with lipid-conjugates, and the potential immune reactions due to repeated dosing with high molecular weight BSA conjugated TFO. In this review, we discuss our latest efforts to enhance the effectiveness of TFO for treating liver fibrosis. We have shown that conjugation of TFOs to M6P-HPMA can enhance TFO delivery to HSCs and has the potential to treat liver fibrosis by inhibiting collagen synthesis. This TFO conjugate shows negligible immunogenicity owing to the use of HPMA, one of the least immunogenic copolymers, thereby making it a suitable and more effective candidate for antifibrotic therapy.

Subcellular fate and off-target effects of siRNA, shRNA, and miRNA

RNA interference (RNAi) strategies include double-stranded RNA (dsRNA), small interfering RNA (siRNA), short hairpin RNA (shRNA), and microRNA (miRNA). As this is a highly specific technique, efforts have been made to utilize RNAi towards potential knock down of disease-causing genes in a targeted fashion. RNAi has the potential to selectively inhibit gene expression by degrading or blocking the translation of the target mRNA. However, delivering these RNAs to specific cells presents a significant challenge. Some of these challenges result from the necessity of traversing the circulatory system while avoiding kidney filtration, degradation by endonucleases, aggregation with serum proteins, and uptake by phagocytes. Further, non-specific delivery may result in side-effects, including the activation of immune response. We discuss the challenges in the systemic delivery to target cells, cellular uptake, endosomal release and intracellular transport of RNAi drugs and recent progress in overcoming these barriers. We also discuss approaches that increase the specificity and metabolic stability and reduce the off-target effects of RNAi strategy.