Long noncoding RNAs HAND2-AS1 ultrasound microbubbles suppress hepatocellular carcinoma progression by regulating the miR-873-5p/tissue inhibitor of matrix metalloproteinase-2 axis

BACKGROUND Increasing data indicated that long noncoding RNAs(lncRNAs)were directly or indirectly involved in the occurrence and development of tumors,including hepatocellular carcinoma(HCC).Recent studies had found that the expression of lncRNA HAND2-AS1 was downregulated in HCC tissues,but its role in HCC progression is unclear.Ultrasound targeted microbubble destruction mediated gene transfection is a new method to overexpress genes.AIM To study the role of ultrasound microbubbles(UTMBs)mediated HAND2-AS1 in the progression of HCC,in order to provide a new reference for the treatment of HCC.METHODS In vitro,we transfected HAND2-AS1 siRNA into HepG2 cells by UTMBs,and detected cell proliferation,apoptosis,invasion and epithelial-mesenchymal transition(EMT)by cell counting kit-8 assay,flow cytometry,Transwell invasion assay and Western blotting,respectively.In addition,we transfected miR-837-5p mimic into UTMBs treated cells and observed the changes of cell behavior.Next,the UTMBs treated HepG2 cells were transfected together with miR-837-5p mimic and tissue inhibitor of matrix metalloproteinase-2(TIMP2)overexpression vector,and we detected cell proliferation,apoptosis,invasion and EMT.In vivo,we established a mouse model of subcutaneous transplantation of HepG2 cells and observed the effect of HAND2-AS1 silencing on tumor formation ability.RESULTS We found that UTMBs carrying HAND2-AS1 restricted cell proliferation,invasion,and EMT,encouraged apoptosis,and HAND2-AS1 silencing eliminated the effect of UTMBs.Additionally,miR-873-5p targets the gene HAND2-AS1,which also targets the 3’UTR of TIMP2.And miR-873-5p mimic counteracted the impact of HAND2-AS1.Further,miR-873-5p mimic solely or in combination with pcDNA-TIMP2 had been transformed into HepG2 cells exposed to UTMBs.We discovered that TIMP2 reversed the effect of miR-873-5p mimic caused by the blocked signalling cascade for matrix metalloproteinase(MMP)2/MMP9.In vivo results showed that HAND2-AS1 silencing significantly inhibited tumor formation in mice.CONCLUSION LncRNA HAND2-AS1 promotes TIMP2 expression by targeting miR-873-5p to inhibit HepG2 cell growth and delay HCC progression.

Ultrasound microbubbles combined with liposome-mediated pNogo-R shRNA delivery into neural stem cells

In the present study, ultrasound-mediated microbubble destruction （UMMD） alone and combined with liposome technology was used as a novel nonviral technique to transfect a Nogo receptor （Nogo-R） shRNA plasmid （pNogo-R shRNA） into neural stem cells （NSCs）. Using green fluorescent protein as a reporter gene, transfection efficiency of NSCs was significantly higher in the group transfected with UMMD combined with liposomes compared with that of the group transfected with UMMD or liposomes alone, and did not affect cell vitality. In addition, Nogo-R mRNA and protein expression was dramatically decreased in the UMMD combined with liposome-mediated group compared with that of other groups after 24 hours of transfection. The UMMD technique combined with liposomes is a noninvasive gene transfer method, which showed minimal effects on cell viability and effectively increased transfer of Nogo-R shRNA into NSCs.

Ultrasound-triggered Microbubble Destruction in Combination with Cationic Lipid Microbubbles Enhances Gene Delivery

This study aimed to examine the preparation of cationic lipid microbubble（CLM）,and evaluate its physical and chemical properties and toxicity,measure the gene transfection efficiency by ultrasound triggered microbobble destruction（UTMD） in combination with CLM.The CLM was prepared by the method of the thin film hydration,and its morphology was observed under the electron microscopy at 1st,3rd,7th,10th,and 14th day after preparation,respectively.The size,Zeta potential and stability of CLM were tested.The acute toxicity of CLM was assessed.The green fluorescent protein gene（EGFP） transfection efficiency was evaluated.The experiment grouping was as follows：naked plasmid group（P group）,ultrasonic irradiation plus naked plasmid group（P-US group）,naked plasmid plus CLM group（P-CLM group）,naked plasmid plus ultrasound and CLM group（UTMD group）.The expression of EGFP was detected by fluorescent microscopy and flow cytometry.The results showed that CLMs were spherical in shape,with the similar size and good distribution degree under the light and electron microscopies.The size of CLMs was varied from 250.4±88.3 to 399.0±99.8 nm and the Zeta potential of CLMs from 18.80±4.97 to 20.1±3.1 mV.The EGFP expression was the strongest in the UTMD group,followed by the P-CLM group,P-US group and P group.Flow cytometry results were consistent with those of fluorescent microscopy.The transfection efficiency was substantially increased in the P-US group,P-CLM group and UTMD group as compared with that in the P group,almost 7 times,10 times and 30 times higher than that in the P group respectively.It is suggested that CLMs prepared by the method of thin film hydration are uniform in diameter,and proved non-toxic.UTMD combined with CLM can significantly increase the transfection efficiency of EGFP to targeted cells.

Interaction between encapsulated microbubbles:A finite element modelling study

Theoretical studies on the multi-bubble interaction are crucial for the in-depth understanding of the mechanism behind the applications of ultrasound contrast agents （UCAs） in clinics. A two-dimensional （2D） axisymmetric finite element model （FEM） is developed here to investigate the bubble-bubble interactions for UCAs in a fluidic environment. The effect of the driving frequency and the bubble size on the bubble interaction tendency （viz., bubbles＇ attraction and repulsion）, as well as the influences of bubble shell mechanical parameters （viz., surface tension coefficient and viscosity coefficient） are discussed. Based on FEM simulations, the temporal evolution of the bubbles＇ radii, the bubble-bubble distance, and the distribution of the velocity field in the surrounding fluid are investigated in detail. The results suggest that for the interacting bubble-bubble couple, the overall translational tendency should be determined by the relationship between the driving frequency and their resonance frequencies. When the driving frequency falls between the resonance frequencies of two bubbles with different sizes, they will repel each other, otherwise they will attract each other. For constant acoustic driving parameters used in this paper, the changing rate of the bubble radius decreases as the viscosity coefficient increases, and increases first then decreases as the bubble shell surface tension coefficient increases, which means that the strength of bubble-bubble interaction could be adjusted by changing the bubble shell visco-elasticity coefficients. The current work should provide a powerful explanation for the accumulation observations in an experiment, and provide a fundamental theoretical support for the applications of UCAs in clinics.

Targeted Antagonism of Vascular Endothelial Growth Factor Reduces Mortality of Mice with Acute Respiratory Distress Syndrome

Summary:Acute respiratory distress syndrome(ARDS)is associated with a mortality of 45%.Our previous rescarch indicated that anti-vascular endothelial growth factor(VEGF)could maintain the normal structure and function of the respiratory barrier.However,systemic application of VEGF antagonists would lead to animal death.This study attempts to study the targeted drug delivery for ARDS.In this study,we used soluble fims-like tyrosine kinase-1(sFlt)-targeted ultrasound microbubbles to antagonize the effect of VEGF on lung tissue.Ninety male BALB/C mice were randomly assigned to 6 groups:phosphate buffer saline(PBS)group(PBS+PBS);blank group(PBS+empty microbubbles);lipopolysaccharide(LPS)group(LPS+PBS);ARDS group(LPS tempty microbubbles);control group(PBS+sFlt microbubbles);and treatment group(LPS+sFIt microbubbles).After administration of LPS or PBS in the corresponding groups,the sFlt-targeted microbubbles or empty microbubbles were injected into the blood circulation.Then the lungs were irradiated with ultrasound,which ruptured the drug-loaded microbubbles and helped release drugs to the lung tissues targeted.The lung injury score,lung wet/dry ratio(W/D),liver and kidney functions,and the mortality of the mice in all groups were investigated at the predetermined time point.The difference in mortality between groups was examined by Fisher test.Other data were analyzed by onc-way analysis of variance(ANOVA).A value of P<0.05 indicates that the difference was significant.The results showed that the PaO2 levels were normal in the PBS group,the blank group,and the control group.The LPS group and ARDS group showed significant hypoxia.PaO2 was improved significantly in the treatment group.The lung injury score and W/D were normal in the PBS group,the blank group,and the control group.The lung injury score and W/D increased significantly in the LPS group and ARDS group and decreased in the treatment group(P<0.05).The mortality rate of the ARDS model was 60%(95%confidence interval 47.5%-72.5%),and that with sFlt-targeted microbubbles was significantly lower at only 40%(95%confidence interval 27.5%-52.5%,P<0.05).It was concluded that anti-VEGF with sFIt targeted ultrasound microbubbles attenuated the lung injury and ultimately reduced the 7-day mortality effectively.It might be a suitable therapeutic tool for the treatment of ARDS.