Bioresponsive Chimaeric Polymersomes Mediate Sustained and Liver-Specific siRNA Transfection In Vivo.

The silencing of disease-causing genes with small interfering RNA (siRNA) offers a particularly effective therapeutic strategy for different disorders; however, its clinical efficacy relies on the development of nontoxic and tissue-specific delivery vehicles. Herein, we report that bioresponsive chimaeric polymersomes (BCP) with short poly(ethylenimine) as inner shell mediate highly efficacious, sustained, and liver-specific siRNA transfection in vivo. BCP exhibited remarkable encapsulation efficiencies of siRNA (95-100%) at siRNA-feeding contents of 15-25 wt %, to afford stable, small-sized (55-64 nm), and neutral-charged BCP-siRNA. siApoB-Loaded BCP (BCP-siApoB) outperformed lipofectamine counterparts and silenced 93% of ApoB mRNA in HepG2 cells at 50 nM siApoB without inducing cytotoxicity. Intriguingly, the in vivo studies using wild-type C57BL/6 mice revealed that BCP-siApoB preferentially accumulated in the liver, and a single dose of 4.5 mg/kg achieved over 90% downregulation of ApoB mRNA for at least 10 days. The systemic administration of BCP-siApoB at 4.5 mg/kg every 2 weeks or 1.5 mg/kg weekly in diet-induced obese mice could also achieve up to 80% silencing of ApoB mRNA. The liver specificity and silencing efficacy of BCP-siApoB could further be improved by decorating it with the trivalent N-acetylgalactosamine (TriGalNAc) ligand. These bioresponsive and liver-specific chimaeric polymersomes provide an enabling technology for siRNA therapy of various liver-related diseases.

Aberrant peribiliary gland niche exacerbates fibrosis in primary sclerosing cholangitis and a potential therapeutic strategy.

Primary sclerosing cholangitis (PSC) is a rare but progressive and fatal autoimmune disease without clear pathogenesis and effective therapies. Peribiliary macrophage recruitment and peribiliary gland (PBG) proliferation and expansion have been associated with various cholangiopathies. This study aimed to evaluate the involvement of the PBG niche and macrophages in PSC progression, potential treatment strategies, and the underlying mechanism in acute and chronic experimental PSC. First, the upregulation of chemokines and fibrosis in PSC patients was confirmed via RNA-seq analysis. In vivo data illustrated that inflammation and fibrosis are the main characteristics, and recession of these can effectively interfere with PSC. Histopathological staining and RT-PCR revealed that more significant ductular reaction (DR) and PBG proliferation in the chronic PSC model, in which fibrosis mainly accumulated in the peribiliary area. In vitro, a transwell migration experiment showed that MCP-1 secreted by cholangiocytes in PBG niche, which recruited monocyte-derived macrophages (MoMFs) to the peribiliary area and promoted inflammation and fibrosis. Then, the luciferase assay and EMSA showed that POU6F1 could activate MCP-1 transcription. Furthermore, 18ß-Glycyrrhetinic acid (GA) reduced macrophages and fibrosis accumulated in the peribiliary, space and reduced PBG proliferation to benefit acute and chronic PSC models. Collectively, our results indicated that POU6F1 transcriptionally activates MCP-1, promoting the recruitment and infiltration of MoMFs and fibrosis into the PBG niche in PSC mouse models, and GA effectively suppressed the above phenotypes. These findings provide potential targets and a theoretical basis for the clinical treatment of PSC.

The contribution of proteasomal impairment to autophagy activation by C9orf72 poly-GA aggregates.

BACKGROUND: Poly-GA, a dipeptide repeat protein unconventionally translated from GGGGCC (G4C2) repeat expansions in C9orf72, is abundant in C9orf72-related amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9orf72-ALS/FTD). Although the poly-GA aggregates have been identified in C9orf72-ALS/FTD neurons, the effects on UPS (ubiquitin-proteasome system) and autophagy and their exact molecular mechanisms have not been fully elucidated. RESULTS: Herein, our in vivo experiments indicate that the mice expressing ploy-GA with 150 repeats instead of 30 repeats exhibit significant aggregates in cells. Mice expressing 150 repeats ploy-GA shows behavioral deficits and activates autophagy in the brain. In vitro findings suggest that the poly-GA aggregates influence proteasomal by directly binding proteasome subunit PSMD2. Subsequently, the poly-GA aggregates activate phosphorylation and ubiquitination of p62 to recruit autophagosomes. Ultimately, the poly-GA aggregates lead to compensatory activation of autophagy. In vivo studies further reveal that rapamycin (autophagy activator) treatment significantly improves the degenerative symptoms and alleviates neuronal injury in mice expressing 150 repeats poly-GA. Meanwhile, rapamycin administration to mice expressing 150 repeats poly-GA reduces neuroinflammation and aggregates in the brain. CONCLUSION: In summary, we elucidate the relationship between poly-GA in the proteasome and autophagy: when poly-GA forms complexes with the proteasome, it recruits autophagosomes and affects proteasome function. Our study provides support for further promoting the comprehension of the pathogenesis of C9orf72, which may bring a hint for the exploration of rapamycin for the treatment of ALS/FTD.

Aristolochic acids exposure was not the main cause of liver tumorigenesis in adulthood.

Aristolochic acids (AAs) have long been considered as a potent carcinogen due to its nephrotoxicity. Aristolochic acid I (AAI) reacts with DNA to form covalent aristolactam (AL)-DNA adducts, leading to subsequent A to T transversion mutation, commonly referred as AA mutational signature. Previous research inferred that AAs were widely implicated in liver cancer throughout Asia. In this study, we explored whether AAs exposure was the main cause of liver cancer in the context of HBV infection in mainland China. Totally 1256 liver cancer samples were randomly retrieved from 3 medical centers and a refined bioanalytical method was used to detect AAI-DNA adducts. 5.10% of these samples could be identified as AAI positive exposure. Whole genome sequencing suggested 8.41% of 107 liver cancer patients exhibited the dominant AA mutational signature, indicating a relatively low overall AAI exposure rate. In animal models, long-term administration of AAI barely increased liver tumorigenesis in adult mice, opposite from its tumor-inducing role when subjected to infant mice. Furthermore, AAI induced dose-dependent accumulation of AA-DNA adduct in target organs in adult mice, with the most detected in kidney instead of liver. Taken together, our data indicate that AA exposure was not the major threat of liver cancer in adulthood.

Transcytosis mechanisms of cell-penetrating peptides: Cation-independent CC12 and cationic penetratin.

Cell-penetrating peptides (CPPs) can aid in intracellular and in vivo drug delivery. However, the mechanisms of CPP-mediated penetration remain unclear, limiting the development and further application of CPPs. Flow cytometry and laser confocal fluorescence microscopy were performed to detect the effects of different endocytosis inhibitors on the internalization of CC12 and penetratin in ARPE-19 cells. The co-localization of CPPs with the lysosome and macropinosome was detected via an endocytosis tracing experiment. The flow cytometry results showed that chlorpromazine, wortmannin, cytochalasin D, and the ATP inhibitor oligomycin had dose-dependent endocytosis-inhibitory effects on CC12. The laser confocal fluorescence results showed that oligomycin had the most significant inhibitory effect on CC12 uptake; CC12 was co-located with the lysosome, but not with the macropinosome. For penetratin, cytochalasin D and oligomycin had obvious inhibitory effects. The laser confocal fluorescence results indicated that oligomycin had the most significant inhibitory effect on penetratin uptake; the co-localization of penetratin with the lysosome was higher than that with the macropinosome. Cation-independent CC12 and cationic penetratin may be internalized into cells primarily through caveolae and clathrin-mediated endocytosis, and they are typically dependent on ATP. The transport of penetratin could be partly achieved through the direct transmembrane pathway, as the positive charge of penetratin interacts with the negative charge of the cell membrane, and partly through the endocytic pathway.

Kupffer cells play a crucial role in monocrotaline-induced liver injury by producing TNF-α.

Monocrotaline (MCT), an unsaturated pyrrolizidine alkaloid (PA) in plants, is mainly toxic to the lung and liver of mammals. As a commonly used tool for liver injury model, the mechanism of MCT hepatoxicity has still not been fully clarified. Kupffer cells (KCs) are the liver-resident macrophages and have various responses to different toxicants and liver damage. However, the role of KCs in MCT-induced liver injury remains controversial. In current work, we investigated the effects of KCs on MCT-induced liver injury, especially on MCT-induced hepatocyte death. KCs were depleted in Balb/c mice by liposome-entrapped clodronate (Lip/Clo) (0.2 mL/mouse, i.p.) or GdCl3 (0.7 mg/kg, i.p.) before MCT administration (300 mg/kg, i.p.), we found that the Lip/Clo group showed higher efficiency in KCs depletion and stronger hepatoprotective effects against MCT. We also found TNF-α was remarkably decreased after KCs depletion, the experiment of administering anti-TNF-α antibody (20 µg/mouse, i.p.) to MCT-treated animals generated the similar results. To further elaborate the function of KCs, we compared the ALT levels released from co-culturing murine hepatic parenchymal cells (HPCs) and RAW264.7 cells with that from HPCs alone. After the treatment of MCT, the released ALT levels in co-culture system were shown to be dependent on the number of RAW264.7 cells, while the anti-TNF-α antibody could suppress it. Finally, we discovered RIPK3/MLKL pathway might be activated by TNF-α released from KCs, and subsequently induced hepatocyte necrosis. Noteworthy, the known mechanisms including ER stress and NF-κB pathways were also found to be involved in the activation of KCs. In conclusion, our study reveals a further mechanism to MCT-induced hepatoxicity mediated directly by KCs via producing TNF-α.

Corrigendum to: Aristolochic acid I induces impairment in spermatogonial stem cell in rodents.

[This corrects the article DOI: 10.1093/toxres/tfab038.].

Profiling pharmacokinetics of double-negative T cells and cytokines via a single intravenous administration in NSG mice.

This study was intended to delineate the profile of double-negative T cells (DNTs) in NOD.Cg-Prkdcscid Il2rgtm1wj /SzJ mice and cytokines released from DNTs in vivo and in vitro. Total 4 × 107 cells of RC1012 injection per mice were intravenously infused. IFN-γ, TNF-α, IL-1ß, IL-2, IL-4, IL-6, IL-10 were measured in vivo and in vitro. A quantitative polymerase chain reaction (PCR) was employed to determine the gene copies of Notch2-NLA per DNT cell from collected organs. Cytokines were significantly increased in vitro (4 h) and in vivo (3 h). DNT cells were distributed into the lung, liver, heart, and kidney earlier, and redistributed to lymphocyte homing spleen and bone marrow, which seemed to frame a two-compartment pharmacokinetics (PK) model but more data are needed to confirm this, and the clearance of DNT cells fell into first-order kinetics.

Aristolochic acid I induces impairment in spermatogonial stem cell in rodents.

Aristolochic acid I (AAI) is a natural bioactive substance found in plants from the Aristolochiaceae family and impairs spermatogenesis. However, whether AAI-induced spermatogenesis impairment starts at the early stages of spermatogenesis has not yet been determined. Spermatogonial stem cells (SSCs) are undifferentiated spermatogonia that balance self-renewing and differentiating divisions to maintain spermatogenesis throughout adult life and are the only adult stem cells capable of passing genes onto the next generation. The objective of this study was to investigate whether AAI impairs SSCs during the early stages of spermatogenesis. After AAI treatment, we observed looser, smaller and fewer colonies, decreased cell viability, a decreased relative cell proliferation index, and increased apoptosis in SSCs in a concentration- and/or time-dependent manner. Additionally, AAI promoted apoptosis in SSCs, which was accompanied by upregulation of caspase 3, P53 and BAX expression and downregulation of Bcl-2 expression, and suppressed autophagy, which was accompanied by upregulation of P62 expression and downregulation of ATG5 and LC3B expression, in a concentration-dependent manner. Then we found that AAI impaired spermatogenesis in rats, as identified by degeneration of the seminiferous epithelium, and increased apoptosis of testicular cells. Taken together, our findings demonstrate that AAI causes damage to SSCs and implicate apoptosis and autophagy in this process. The impairment of SSCs may contribute to AAI-induced testicular impairment. Our findings provide crucial information for the human application of botanical products containing trace amounts of AAI.

ZEB1 Mediates Bone Marrow Mesenchymal Stem Cell Osteogenic Differentiation Partly via Wnt/ß-Catenin Signaling.

Zinc finger E-box-binding homebox 1 (ZEB1) is a zinc-finger transcription factor best known for its role in promoting the epithelial-mesenchymal transition, which is also related to osteogenesis. Here, ZEB1 was investigated for its role in the commitment of bone marrow mesenchymal stem cells (BMSCs) to osteoblasts. In vitro, ZEB1 expression decreased following osteogenic differentiation. Furthermore, silencing of ZEB1 in BMSCs promoted osteogenic activity and mineralization. The increase in osteogenic differentiation induced by si-ZEB1 could be partly rescued by the inhibition of Wnt/ß-catenin (si-ß-catenin). In vivo, knockdown of ZEB1 in BMSCs inhibited the rapid bone loss of ovariectomized (OVX) mice. ZEB1 expression has also been negatively associated with bone mass and bone formation in postmenopausal women. In conclusion, ZEB1 is an essential transcription factor in BMSC differentiation and may serve as a potential anabolic strategy for treating and preventing postmenopausal osteoporosis (PMOP).

Prevention of D-GalN/LPS-induced ALI by 18ß-glycyrrhetinic acid through PXR-mediated inhibition of autophagy degradation.

Acute liver injury (ALI) has multiple causes and results in liver dysfunction. Severe or persistent liver injury eventually leads to liver failure and even death. Pregnane X receptor (PXR)-null mice present more severe liver damage and lower rates of autophagy. 18ß-glycyrrhetinic acid (GA) has been proposed as a promising hepatoprotective agent. We hypothesized that GA significantly alleivates D-GalN/LPS-induced ALI, which involved in PXR-mediated autophagy and lysosome biogenesis. We found that GA can significantly decrease hepatocyte apoptosis and increase the hepatic autophagy marker LC3-B. Ad-mCherry-GFP-LC3 tandem fluorescence, RNA-seq and real-time PCR indicated that GA may stabilize autophagosomes and lysosomes and inhibit autophagosome-lysosome fusion. Simultaneously, GA markedly activates PXR, even reversing the D-GalN/LPS-induced reduction of PXR and its downstream genes. In contrast, GA has a weak protective effect in pharmacological inhibition of PXR and PXR-null mice, which significantly affected apoptosis- and autophagy-related genes. PXR knockout interferes with the stability of autophagosomes and lysosomes, preventing GA reducing the expression of lysosomal genes such as Cst B and TPP1, and suppressing autophagy flow. Therefore, we believe that GA increases autophagy by inhibiting autophagosome-lysosome fusion and blocked autophagy flux via activation of PXR. In conclusion, our results show that GA activates PXR to regulate autophagy and lysosome biogenesis, represented by inhibiting autophagosome-lysosome fusion and stabilization of lysosome. These results identify a new mechanism by which GA-dependent PXR activation reduces D-GalN/LPS-induced acute liver injury.

miR-34a-5p regulates PINK1-mediated mitophagy via multiple modes.

AIMS: PTEN induced putative kinase 1 (PINK1)-mediated mitophagy process is tightly associated with various age-dependent diseases in mammals. The roles of miRNAs (miRNAs) in the PINK1-mediated mitophagy process are not fully understood. Here we discovered that miR-34a-5p suppresses PINK1 expression directly though two post-transcriptional non-classical binding modes, resulting in inhibition of PINK1-mediated mitophagy process. MAIN METHODS: For in vivo experiments, brains were dissected from 8 weeks old and 40 weeks old C57BL/6 male mice to measure miR-34a-5p expression and PINK1 expression. For in vitro experiments, overexpression of miR-34a-5p mimics in HEK293 cells was performed to investigate the effect of miR-34a-5p on PINK1 expression and its regulatory mechanism, parkin recruitment and mitophagy process. KEY FINDINGS: The level of miR-34a-5p was upregulated and the level of PINK1 mRNA was downregulated in brains of aged mice. Both the 3'-untranslated region (3'UTR) and the Coding DNA sequence (CDS) of PINK1 mRNA were bound to the non-seed region of miR-34a-5p, rather than the seed region, resulting in a decrease in PINK1 expression. Endogenous miR-34a-5p knockout increased PINK1 expression. Further results indicated that miR-34a-5p inhibits mitophagy process by reduction of PINK1. miR-34a-5p hinders phosphorylated Ser65-ubiquitin (pS65-Ub) accumulation, prevents the mitochondrial recruitment of Parkin, attenuates ubiquitination and delays the clearance of damaged mitochondria. SIGNIFICANCE: We firstly found that miR-34a-5p suppresses PINK1 directly and further regulates mitophagy through non-canonical modes. This finding hints at a crucial role of miR-34a-5p implicated in accelerating the pathogenesis of age-related neurological diseases.

Aristolochic acid I promoted clonal expansion but did not induce hepatocellular carcinoma in adult rats.

Aristolochic acid I (AAI) is a well-known nephrotoxic carcinogen, which is currently reported to be also associated with hepatocellular carcinoma (HCC). Whether AAI is a direct hepatocarcinogen remains controversial. In this study we investigated the association between AAI exposure and HCC in adult rats using a sensitive rat liver bioassay with several cofactors. Formation of glutathione S-transferase placental form-positive (GST-P+) foci was used as the marker for preneoplastic lesions/clonal expansion. We first conducted a medium-term (8 weeks) study to investigate whether AAI had any tumor-initiating or -promoting activity. Then a long-term (52 weeks) study was conducted to determine whether AAI can directly induce HCC. We showed that oral administration of single dose of AAI (20, 50, or 100 mg/kg) in combination with partial hepatectomy (PH) to stimulate liver proliferation did not induce typical GST-P+ foci in liver. In the 8-week study, only high dose of AAI (10 mg · kg-1 · d-1, 5 days a week for 6 weeks) in combination with PH significantly increased the number and area of GST-P+ foci initiated by diethylnitrosamine (DEN) in liver. Similarly, only high dose of AAI (10 mg· kg-1· d-1, 5 days a week for 52 weeks) in combination with PH significantly increased the number and area of hepatic GST-P+ foci in the 52-week study. No any nodules or HCC were observed in liver of any AAI-treated groups. In contrast, long-term administration of AAI (0.1, 1, 10 mg· kg-1· d-1) time- and dose-dependently caused death due to the occurrence of cancers in the forestomach, intestine, and/or kidney. Besides, AAI-DNA adducts accumulated in the forestomach, kidney, and liver in a time- and dose-dependent manner. Taken together, AAI promotes clonal expansion only in the high-dose group but did not induce any nodules or HCC in liver of adult rats till their deaths caused by cancers developed in the forestomach, intestine, and/or kidney. Findings from our animal studies will pave the way for further large-scale epidemiological investigation of the associations between AA and HCC.

Nuclear miR-30b-5p suppresses TFEB-mediated lysosomal biogenesis and autophagy.

Lysosome is a crucial organelle in charge of degrading proteins and damaged organelles to maintain cellular homeostasis. Transcription factor EB (TFEB) is the master transcription factor regulating lysosomal biogenesis and autophagy. Under external stimuli such as starvation, dephosphorylated TFEB transports into the nucleus to specifically recognize and bind to the coordinated lysosomal expression and regulation (CLEAR) elements at the promotors of autophagy and lysosomal biogenesis-related genes. The function of TFEB in the nucleus is fine regulated but the molecular mechanism is not fully elucidated. In this study, we discovered that miR-30b-5p, a small RNA which is known to regulate a series of genes through posttranscriptional regulation in the cytoplasm, was translocated into the nucleus, bound to the CLEAR elements, suppressed the transcription of TFEB-dependent downstream genes, and further inhibited the lysosomal biogenesis and the autophagic flux; meanwhile, knocking out the endogenous miR-30b-5p by CRISPR/Cas9 technique significantly increased the TFEB-mediated transactivation, resulting in the increased expression of autophagy and lysosomal biogenesis-related genes. Overexpressing miR-30b-5p in mice livers showed a decrease in lysosomal biogenesis and autophagy. These in vitro and in vivo data indicate that miR-30b-5p may inhibit the TFEB-dependent transactivation by binding to the CLEAR elements in the nucleus to regulate the lysosomal biogenesis and autophagy. This novel mechanism of nuclear miRNA regulating gene transcription is conducive to further elucidating the roles of miRNAs in the lysosomal physiological functions and helps to understand the pathogenesis of abnormal autophagy-related diseases.

MiR-629-5p promotes the invasion of lung adenocarcinoma via increasing both tumor cell invasion and endothelial cell permeability.

Tumor invasion underlies further metastasis, the leading cause for cancer-related deaths. Deregulation of microRNAs has been identified associated with the malignant behavior of various cancers, including lung adenocarcinoma (LUAD), the major subtype of lung cancer. Here, we showed the significantly positive correlation between miR-629-5p level and tumor invasion in LUAD specimens (n = 49). In a human LUAD metastasis mouse model, H1650 cells (high level of miR-629-5p) were more aggressive than A549 cells (low level of miR-629-5p) in vivo, including higher incidence of vascular invasion and pulmonary colonization. Ectopic expression of miR-629-5p in A549 cells also increased their invasive capability. Then we identified that miR-629-5p promotes LUAD invasion in a mode of dual regulation via tumor cells invasion and endothelial cells permeability, respectively. In tumor cells, miR-629-5p enhanced motility and invasiveness of tumor cells by directly targeting PPWD1 (a cyclophilin), which clinically related to tumor invasion in LUAD specimens. Restoring PPWD1 protein significantly attenuated the invasion-promoting effects of miR-629-5p. Besides, exosomal-miR-629-5p secreted from tumor cells could be transferred to endothelial cells and increased endothelial monolayers permeability by suppressing CELSR1 (a nonclassic-type cadherin), which had a low level in the endothelial cells of invasive LUAD specimens. Activating the expression of CELSR1 in endothelial cells markedly blocked the effect of miR-629-5p. Our study suggests the dual roles of miR-629-5p in tumor cells and endothelial cells for LUAD invasion, implying a therapeutic option to targeting miR-629-5p using the "one stone, two birds" strategy in LUAD.

A proton-coupled organic cation antiporter is involved in the blood-brain barrier transport of Aconitum alkaloids.

ETHNOPHARMACOLOGICAL RELEVANCE: The herbs of Aconitum are the essential Traditional Chinese medicine and have played an indispensable role in many Asian countries for thousands of years to treat critical illnesses, and chronic, stubborn diseases. However, Aconitum may induce severe neurotoxicity and even death. So far the mechanism of Aconitum penetrating the blood-brain barrier (BBB) is still unclear. AIM OF THE STUDY: To determine whether influx transporters contribute to the brain uptake of the highly toxic alkaloids in Aconitum including aconitine (AC), mesaconitine (MA) and hypaconitine (HA). MATERIALS AND METHODS: The uptake of AC, MA and HA was characterized using in vitro hCMEC/D3 model and in situ mouse brain perfusion. In hCMEC/D3 cells, the effect of incubation temperature, time, initial drug concentration, energy (NaN3), extracellular and intracellular pH (FCCP and NH4Cl), the prototypical substrates/inhibitors of known organic cation transporting carriers and trans-stimulation (pre-incubating with pyrilamine and diphenhydramine) on the cellular uptake were studied. In addition, the effect of silencing OCTN1, OCTN2 and PMAT by specific siRNA was investigated. In mice, the contribution of the proton-coupled antiporter on the brain uptake of Aconitum was investigated by chemical inhibition. RESULTS: In hCMEC/D3 cells, AC, MA and HA were each taken up in a temperature-, time- and concentration-dependent manner, which were reduced by NaN3 and FCCP. Regulation of extracellular and intracellular pH as well as trans-stimulation studies showed that AC, MA and HA were transported by a proton-coupled antiporter expressed at the plasma membrane that could also transport pyrilamine and diphenhydramine. Each uptake was markedly inhibited by various cationic drugs, but insensitive to the prototypical substrates/inhibitors of identified organic cation transporting carriers, such as OCTs, PMAT, MATEs and OCTNs. In addition, silence of OCTN1, OCTN2 and PMAT had no significant inhibitory effect on the uptake of AC, MA and HA. In mice, the brain uptake of each alkaloid measured by in situ brain perfusion was suppressed by diphenhydramine when the transport capacity of P-gp/Bcrp at the BBB was chemically inhibited. CONCLUSIONS: A novel proton-coupled organic cation antiporter plays a predominant role in the blood to brain influx of AC, MA and HA at the BBB, and thus affect the safety of Aconitum species.

(5R)-5-hydroxytriptolide ameliorates liver lipid accumulation by suppressing lipid synthesis and promoting lipid oxidation in mice.

AIMS: (5R)-5-hydroxytriptolide (LLDT-8) is a triptolide analog with excellent capability against cancers, cerebral ischemic injury and rheumatoid arthritis. Here, we discovered its hepatoprotective effects in a mouse model of non-alcoholic fatty liver disease (NAFLD) by ameliorating liver lipid accumulation. MAIN METHODS: Male C57BL/6J mice were fed with a high-fat/high-fructose (HFHFr) diet for 29 weeks to induce the pathological phenomena of NAFLD. Then the mice were treated with LLDT-8 (0.5mg/kg and 1mg/kg) or Vehicle for 8 weeks. Finally, the serum biochemical indexes, liver histological features, fatty acids (FAs) profile and related gene expression in liver were detected to investigate the effect of LLDT-8 on lipid accumulation and its possible mechanism. KEY FINDINGS: LLDT-8 treatment significantly inhibited hepatic injury featured by the decrease of serum alanine aminotransferase (ALT) and aspartate transaminase (AST), the lessening of hepatic ballooning and macrovesicular steatosis. Moreover, LLDT-8 could downregulate the expression of stearoyl-CoA desaturase 1 (SCD1), which further led to the lower ratios of C16:1/C16:0 and C18:1/C18:0 and thus inhibited lipid synthesis. LLDT-8 treatment also could upregulate liver peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1a (Cpt1a), peroxisomal acyl-CoA oxidase 1 (Acox1), long-chain acyl-CoA dehydrogenase (Acadl) and medium-chain acyl-CoA dehydrogenase (Acadm) expression levels involved in fatty acids oxidation (FAO) and markedly promoted lipolysis. SIGNIFICANCE: Our results provide a novel application of LLDT-8 in improving NAFLD.

MiR-1205 functions as a tumor suppressor by disconnecting the synergy between KRAS and MDM4/E2F1 in non-small cell lung cancer.

Activated KRAS is frequently observed and paralleled by inactivating of tumor suppressors in lung cancer, while the mechanisms remained elusive. Here, our study revealed a microRNA was involved in KRAS overexpression, activation of KRAS signaling and its synergy with inactivating of tumor suppressor genes. miR-1205 was selected by its sequence-dependent inhibition on KRAS and negative clinical correlation with KRAS. A549 and H460 cells carrying mutant KRAS, were sensitive to the growth inhibition and G1/S arrest induced by miR-1205. Target analysis revealed that miR-1205 could simultaneously downregulate the expression levels of MDM4 and E2F1, which were downstream of KRAS and synergistic with KRAS. Silencing of MDM4 or E2F1 inhibited cellular proliferation. MiR-1205 decreased the protein levels of MDM4 and E2F1 via directly binding to the coding sequence of E2F1 and 3'UTR of MDM4. Meanwhile, blocking RAS-MAPK signaling using KRAS siRNA or ERK1/2 inhibitor exerted similar inhibitory effects on MDM4 and E2F1. Forced expression of KRAS partially restored the inhibition of miR-1205 on MDM4 and E2F1. Overexpression of KRAS, MDM4 or E2F1 could partially rescued the growth inhibition of miR-1205 in vitro. More importantly, miR-1205 strongly inhibited the tumor growth of A549 xenografts in nude mice and decreased the protein levels of KRAS, MDM4 and E2F1 in tumor tissues. Together, our study firstly confirmed a potential synergy between KRAS and MDM4/E2F1 which are p53/RB inactivators in non-small cell lung cancer, and identified miR-1205 as a potent destructor of this synergy, making miR-1205 function as a tumor suppressor in vitro and in vivo.

Regulatory network of miRNA on its target: coordination between transcriptional and post-transcriptional regulation of gene expression.

MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs that participate in a majority of biological processes via regulating target gene expression. The post-transcriptional repression through miRNA seed region binding to 3' UTR of target mRNA is considered as the canonical mode of miRNA-mediated gene regulation. However, emerging evidence suggests that other regulatory modes exist beyond the canonical mechanism. In particular, the function of intranuclear miRNA in gene transcriptional regulation is gradually revealed, with evidence showing their contribution to gene silencing or activating. Therefore, miRNA-mediated regulation of gene transcription not only expands our understanding of the molecular mechanism underlying miRNA regulatory function, but also provides new evidence to explain its ability in the sophisticated regulation of many bioprocesses. In this review, mechanisms of miRNA-mediated gene transcriptional and post-transcriptional regulation are summarized, and the synergistic effects among these actions which form a regulatory network of a miRNA on its target are particularly elaborated. With these discussions, we aim to emphasize the importance of miRNA regulatory network on target gene regulation and further highlight the potential application of the network mode in the achievement of a more effective and stable modulation of the target gene expression.