The use of MMP2 antibody-conjugated cationic microbubble to target the ischemic myocardium, enhance Timp3 gene transfection and improve cardiac function

Cardiac gene delivery using ultrasound: State of the field

Over the past two decades, there has been tremendous and exciting progress toward extending the use of medical ultrasound beyond a traditional imaging tool. Ultrasound contrast agents, typically used for improved visualization of blood flow, have been explored as novel non-viral gene delivery vectors for cardiovascular therapy. Given this adaptation to ultrasound contrast-enhancing agents, this presents as an image-guided and site-specific gene delivery technique with potential for multi-gene and repeatable delivery protocols-overcoming some of the limitations of alternative gene therapy approaches. In this review, we provide an overview of the studies to date that employ this technique toward cardiac gene therapy using cardiovascular disease animal models and summarize their key findings.

Development of exosome membrane materials-fused microbubbles for enhanced stability and efficient drug delivery of ultrasound contrast agent

Lipid-coated microbubbles are widely used as an ultrasound contrast agent, as well as drug delivery carriers. However, the two main limitations in ultrasound diagnosis and drug delivery using microbubbles are the short half-life in the blood system, and the difficulty of surface modification of microbubbles for active targeting. The exosome, a type of extracellular vesicle, has a preferentially targeting ability for its original cell. In this study, exosome-fused microbubbles (Exo-MBs) were developed by embedding the exosome membrane proteins into microbubbles. As a result, the stability of Exo-MBs is improved over the conventional microbubbles. On the same principle that under the exposure of ultrasound, microbubbles are cavitated and self-assembled into nano-sized particles, and Exo-MBs are self-assembled into exosome membrane proteins-embedded nanoparticles (Exo-NPs). The Exo-NPs showed favorable targeting properties to their original cells. A photosensitizer, chlorin e6, was loaded into Exo-MBs to evaluate therapeutic efficacy as a drug carrier. Much higher therapeutic efficacy of photodynamic therapy was confirmed, followed by cancer immunotherapy from immunogenic cell death. We have therefore developed a novel ultrasound image-guided drug delivery platform that overcomes the shortcomings of the conventional ultrasound contrast agent and is capable of simultaneous photodynamic therapy and cancer immunotherapy.

Cardioprotective effect of ultrasound-targeted destruction of Sirt3-loaded cationic microbubbles in a large animal model of pathological cardiac hypertrophy

Pathological cardiac hypertrophy occurs in response to numerous increased afterload stimuli and precedes irreversible heart failure (HF). Therefore, therapies that ameliorate pathological cardiac hypertrophy are urgently required. Sirtuin 3 (Sirt3) is a main member of histone deacetylase class III and is a crucial anti-oxidative stress agent. Therapeutically enhancing the Sirt3 transfection efficiency in the heart would broaden the potential clinical application of Sirt3. Ultrasound-targeted microbubble destruction (UTMD) is a prospective, noninvasive, repeatable, and targeted gene delivery technique. In the present study, we explored the potential and safety of UTMD as a delivery tool for Sirt3 in hypertrophic heart tissues using adult male Bama miniature pigs. Pigs were subjected to ear vein delivery of human Sirt3 together with UTMD of cationic microbubbles (CMBs). Fluorescence imaging, western blotting, and quantitative real-time PCR revealed that the targeted destruction of ultrasonic CMBs in cardiac tissues greatly boosted Sirt3 delivery. Overexpression of Sirt3 ameliorated oxidative stress and partially improved the diastolic function and prevented the apoptosis and profibrotic response. Lastly, our data revealed that Sirt3 may regulate the potential transcription of catalase and MnSOD through Foxo3a. Combining the advantages of ultrasound CMBs with preclinical hypertrophy large animal models for gene delivery, we established a classical hypertrophy model as well as a strategy for the targeted delivery of genes to hypertrophic heart tissues. Since oxidative stress, fibrosis and apoptosis are indispensable in the evolution of cardiac hypertrophy and heart failure, our findings suggest that Sirt3 is a promising therapeutic option for these diseases. STATEMENT OF SIGNIFICANCE: : Pathological cardiac hypertrophy is a central prepathology of heart failure and is seen to eventually precede it. Feasible targets that may prevent or reverse disease progression are scarce and urgently needed. In this study, we developed surface-filled lipid octafluoropropane gas core cationic microbubbles that could target the release of human Sirt3 reactivating the endogenous Sirt3 in hypertrophic hearts and protect against oxidative stress in a pig model of cardiac hypertrophy induced by aortic banding. Sirt3-CMBs may enhance cardiac diastolic function and ameliorate fibrosis and apoptosis. Our work provides a classical cationic lipid-based, UTMD-mediated Sirt3 delivery system for the treatment of Sirt3 in patients with established cardiac hypertrophy, as well as a promising therapeutic target to combat pathological cardiac hypertrophy.

Exosomes and ultrasound: The future of theranostic applications

Biomaterials and pertaining formulations have been very successful in various diagnostic and therapeutic applications because of its ability to overcome pharmacological limitations. Some of them have gained significant focus in the recent decade for their theranostic properties. Exosomes can be grouped as biomaterials, since they consist of various biological micro/macromolecules and possess all the properties of a stable biomaterial with size in nano range. Significant research has gone into isolation and exploitation of exosomes as potential theranostic agent. However, the limitations in terms of yield, efficacy, and target specificity are continuously being addressed. On the other hand, several nano/microformulations are responsive to physical or chemical alterations and were successfully stimulated by tweaking the physical characteristics of the surrounding environment they are in. Some of them are termed as photodynamic, sonodynamic or thermodynamic therapeutic systems. In this regard, ultrasound and acoustic systems were extensively studied for its ability towards altering the properties of the systems to which they were applied on. In this review, we have detailed about the diagnostic and therapeutic applications of exosomes and ultrasound separately, consisting of their conventional applications, drawbacks, and developments for addressing the challenges. The information were categorized into various sections that provide complete overview of the isolation strategies and theranostic applications of exosomes in various diseases. Then the ultrasound-based disease diagnosis and therapy were elaborated, with special interest towards the use of ultrasound in enhancing the efficacy of nanomedicines and nanodrug delivery systems, Finally, we discussed about the ability of ultrasound in enhancing the diagnostic and therapeutic properties of exosomes, which could be the future of theranostics.

Antifibrotic effect of AD-1 on lipopolysaccharide-mediated fibroblast injury in L929 cells and bleomycin-induced pulmonary fibrosis in mice

20(R)-25-methoxyl-dammarane-3β,12β,20-triol (25-OCH₃-PPD, AD-1) is a dammarane ginsenoside that is isolated from Panax notoginseng. The present study aimed to explore its anti-pulmonary fibrosis (PF) effect in vitro and in vivo. L929 cells were treated with 10 μg mL^-1 lipopolysaccharide (LPS) to establish a PF model in vitro and mice were administered with 3.5 mg kg^-1 bleomycin (BLM) by endotracheal intubation to establish a PF model in vivo for investigating the anti-PF effect and its potential mechanism. The results demonstrated that AD-1 reduced the injury, extracellular matrix (ECM) buildup and α-smooth muscle actin (α-SMA) protein expression levels of L929 induced by LPS. Oral administration of AD-1 downregulated the expression of interleukins (such as IL-1β, IL-6 and IL-18), increased the expression of superoxide dismutase (SOD) and glutathione (GSH), reduced the lung coefficient and the content of hydroxyproline (HYP), and mediated the Bax/Bcl-2 protein ratio and P-p53, β-catenin and SIRT3 expression in the lung tissue of mice. Furthermore, AD-1 inhibited the expression levels of TGF-β1, TIMP-1 and α-SMA and reduced inflammatory cell infiltration and collagen deposition in the lung tissue of PF mice. These results indicated that AD-1 could alleviate PF both in vitro and in vivo, and the underlying mechanism may be related to the decrease in ECM deposition and inflammation, the enhancement of antioxidant capacity, and the mediation of lung cell apoptosis and the TGF-β1/TIMP-1/α-SMA signaling pathway, which provide a theoretical basis for the rehabilitation treatment of PF.

Immunologically modified enzyme-responsive micelles regulate the tumor microenvironment for cancer immunotherapy

Immune checkpoint blockade has been proven to have great therapeutic potential and has revolutionized the treatment of tumors. However, various limitations remain, including the low response rate of exhausted T cells and mutual regulation of multiple immunosuppressive cell types that compromise the effect of single-target therapy. Nano-delivery systems can be used to regulate the tumor immune microenvironment in favor of immunotherapy. In this study, we constructed a polypeptide-based micellar system that encapsulates an aryl hydrocarbon receptor (AhR) inhibitor (CH223191) conjugated to T cell activator anti-CD28. The inhibition of AhR activation downregulates the fraction of immunosuppressive cells and effectively inhibits tumor cell metastasis. In addition, the combination with co-stimulatory antibodies improves T-cell activation and synergistically enhances the antitumor effect of AhR inhibitors. The micellar system developed in this study represents a novel and effective tumor immunotherapy approach.

Ultrasonic particles: An approach for targeted gene delivery

Gene therapy has been widely investigated for the treatment of genetic, acquired, and infectious diseases. Pioneering work utilized viral vectors; however, these are suspected of causing serious adverse events, resulting in the termination of several clinical trials. Non-viral vectors, such as lipid nanoparticles, have attracted significant interest, mainly due to their successful use in vaccines in the current COVID-19 pandemic. Although they allow safe delivery, they come with the disadvantage of off-target delivery. The application of ultrasound to ultrasound-sensitive particles allows for a direct, site-specific transfer of genetic materials into the organ/site of interest. This process, termed ultrasound-targeted gene delivery (UTGD), also increases cell membrane permeability and enhances gene uptake. This review focuses on the advances in ultrasound and the development of ultrasonic particles for UTGD across a range of diseases. Furthermore, we discuss the limitations and future perspectives of UTGD.

MicroRNA-197-3p mediates damage to human coronary artery endothelial cells via targeting TIMP3 in Kawasaki disease

Kawasaki disease (KD) causes cardiovascular system injury in children. However, the pathogenic mechanisms of KD have not been well defined. Recently, strong correlation between aberrant microRNAs and KD nosogenesis has been revealed. A role of microRNA-197-3p (miR-197-3p) in the pathogenesis of KD is identified in the present study. Cell proliferation assay showed human coronary artery endothelial cells (HCAECs) were suppressed by serum from KD patients, which was correlated with high levels of miR-197-3p in both KD serum and HCAECs cultured with KD serum. The inhibition of HCAECs by miR-197-3p was confirmed by cells expressing miR-197-3p mimic and miR-197-3p inhibitor. Comparative proteomics analysis and Ingenuity Pathway Analysis (IPA) revealed TIMP3 as a potential target of miR-197-3p, which was demonstrated by western blot and dual-luciferase reporter assays. Subsequently, by detecting the endothelium damage markers THBS1, VWF, and HSPG2, the role of miR-197-3p/TIMP3 in KD-induced damage to HCAECs was confirmed, which was further validated by a KD mouse model in vivo. The expressions of miR-197-3p and its target, TIMP3, are dramatically variational in KD serum and HCAECs cultured with KD serum. Increased miR-197-3p induces HCAECs abnormal by restraining TIMP3 expression directly. Hence, dysregulation of miR-197-3p/TIMP3 expression in HCAECs may be an important mechanism in cardiovascular endothelium injury in KD patients, which offers a feasible therapeutic target for KD treatment.

Ultrasound-assisted C3F8-filled PLGA nanobubbles for enhanced FGF21 delivery and improved prophylactic treatment of diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a serious cardiac complication of diabetes that currently lacks specific treatment. Fibroblast growth factor 21 (FGF21) has been proved to have cardioprotective effect in DCM. However, the insufficient cardiac delivery effect of FGF21 limits its application in DCM. Therefore, to improve the therapeutic efficacy of FGF21 in DCM, an effective drug delivery system is urgently required. In this study, perfluoropropane (C₃F₈) and polyethylenimine (PEI)-doped poly (lactic-co-glycolic acid) (PLGA) nanobubbles (CPPNBs) were synthesized via double-emulsion evaporation and FGF21 was efficiently absorbed (CPPNBs@FGF21) via the electrostatic incorporation effect. CPPNBs@FGF21 could effectively deliver FGF21 to the myocardial tissue through the cavitation effect under low-frequency ultrasound (LFUS). The as-prepared CPPNBs@FGF21 could efficiently load FGF21 after doping with the cationic polymer PEI, and displayed uniform dispersion and favorable biosafety. After filling with C₃F₈, CPPNBs@FGF21 could be used for distribution monitoring through ultrasound imaging. Moreover, CPPNBs@FGF21 significantly downregulated the expression of ANP, CTGF, and caspase-3 mRNA via the action of LFUS owing to increased FGF21 release, therefore exhibiting enhanced inhibition of myocardial hypertrophy, apoptosis, and interstitial fibrosis in DCM mice. In conclusion, we established an effective protein delivery nanocarrier for the diagnosis and prophylactic treatment of DCM. STATEMENT OF SIGNIFICANCE: Diabetic cardiomyopathy (DCM) is a serious cardiac complication of diabetes that currently lacks effective clinical treatments. Fibroblast growth factor 21 (FGF21) can protect cardiomyocytes from diabetic damage, but insufficient cardiac drug delivery limits the application of FGF21 in DCM. In this study, perfluoropropane (C3F8) and polyethylenimine (PEI)-doped poly (lactic-co-glycolic acid) (PLGA) nanobubbles loaded with FGF21 (CPPNBs@FGF21) were developed for the prophylactic treatment of DCM. CPPNBs@FGF21 could effectively deliver the FGF21 to the myocardial tissue through the cavitation effect of low-frequency ultrasound (LFUS). Our results indicated that CPPNBs@FGF21 combined with LFUS could significantly down-regulate the expressions of ANP, CTGF, and caspase-3 mRNA, and as a result, it prevented the myocardial hypertrophy, apoptosis, and interstitial fibrosis of DCM mice. Overall, we established an effective protein delivery nanocarrier for the diagnosis and prophylactic treatment of DCM.

Ultrasound and Magnetic Responsive Drug Delivery Systems for Cardiovascular Application

With the increasing insight into molecular mechanisms of cardiovascular disease, a promising solution involves directly delivering genes, cells, and chemicals to the infarcted myocardium or impaired endothelium. However, the limited delivery efficiency after administration fails to reach the therapeutic dose and the adverse off-target effect even causes serious safety concerns. Controlled drug release via external stimuli seems to be a promising method to overcome the drawbacks of conventional drug delivery systems (DDSs). Microbubbles and magnetic nanoparticles responding to ultrasound and magnetic fields respectively have been developed as an important component of novel DDSs. In particular, several attempts have also been made for the design and fabrication of dual-responsive DDS. This review presents the recent advances in the ultrasound and magnetic fields responsive DDSs in cardiovascular application, followed by their current problems and future reformation.

Microbubbles and Nanobubbles with Ultrasound for Systemic Gene Delivery

The regulation of gene expression is a promising therapeutic approach for many intractable diseases. However, its use in clinical applications requires the efficient delivery of nucleic acids to target tissues, which is a major challenge. Recently, various delivery systems employing physical energy, such as ultrasound, magnetic force, electric force, and light, have been developed. Ultrasound-mediated delivery has particularly attracted interest due to its safety and low costs. Its delivery effects are also enhanced when combined with microbubbles or nanobubbles that entrap an ultrasound contrast gas. Furthermore, ultrasound-mediated nucleic acid delivery could be performed only in ultrasound exposed areas. In this review, we summarize the ultrasound-mediated nucleic acid systemic delivery system, using microbubbles or nanobubbles, and discuss its possibilities as a therapeutic tool.

Repairing the heart: State-of the art delivery strategies for biological therapeutics

Myocardial infarction (MI) is one of the leading causes of mortality worldwide. It is caused by an acute imbalance between oxygen supply and demand in the myocardium, usually caused by an obstruction in the coronary arteries. The conventional therapy is based on the application of (a combination of) anti-thrombotics, reperfusion strategies to open the occluded artery, stents and bypass surgery. However, numerous patients cannot fully recover after these interventions. In this context, new therapeutic methods are explored. Three decades ago, the first biologicals were tested to improve cardiac regeneration. Angiogenic proteins gained popularity as potential therapeutics. This is not straightforward as proteins are delicate molecules that in order to have a reasonably long time of activity need to be stabilized and released in a controlled fashion requiring advanced delivery systems. To ensure long-term expression, DNA vectors-encoding for therapeutic proteins have been developed. Here, the nuclear membrane proved to be a formidable barrier for efficient expression. Moreover, the development of delivery systems that can ensure entry in the target cell, and also correct intracellular trafficking towards the nucleus are essential. The recent introduction of mRNA as a therapeutic entity has provided an attractive intermediate: prolonged but transient expression from a cytoplasmic site of action. However, protection of the sensitive mRNA and correct delivery within the cell remains a challenge. This review focuses on the application of synthetic delivery systems that target the myocardium to stimulate cardiac repair using proteins, DNA or RNA.

Targeted galectin-7 inhibition with ultrasound microbubble targeted gene therapy as a sole therapy to prevent acute rejection following heart transplantation in a Rodent model

BACKGROUND

Despite significant advances in transplantation, acute cellular rejection (AR) remains a major obstacle that is most prevalent in the first months post heart transplantation (HT). Current treatments require high doses of immunosuppressive drugs followed by maintenance therapies that have systemic side effects including early infection. In this study, we attempted to prevent AR with a myocardial-targeted galectin-7-siRNA delivery method using cationic microbubbles (CMBs) combined with ultrasound targeted microbubble destruction (UTMD) to create local immunosuppression in a rat abdominal heterotopic heart transplantation acute rejection model.

METHODS AND RESULTS

Galectin-7-siRNA (siGal-7) bound to CMBs were synthesized and effective ultrasound-targeted delivery of siGal-7 into target cells confirmed in vitro. Based on these observations, three transplant rat models were tested：①isograft (ISO); ② Allograft (ALLO) +UTMD; and ③ALLO + PBS. UTMD treatments were administered at 1, 3, 5, 7 days after HT. Galectin 7 expression was reduced by 50% compared to ALLO + PBS (p < 0.005), and this was associated with significant reductions in both galectin 7 and Interleukin-2 protein levels (p < 0.001). The ALLO + UTMD group had Grade II or less inflammatory infiltration and myocyte damage in 11/12 rats using International Society For Heart and Lung Transplantation grading, compared to 0/12 rats with this grading in the ALLO + PBS group at 10 days post HT (p < 0.001).

CONCLUSIONS

Ultrasound-targeted galectin-7-siRNA knockdown with UTMD can prevent acute cellular rejection in the early period after allograft heart transplantation without the need for systemic immunosuppression.

KEY WORDS

Microbubble, Acute Rejection, Heart Transplantation, Galectin-7, RNA.

Ultrasound-Responsive Cavitation Nuclei for Therapy and Drug Delivery

Therapeutic ultrasound strategies that harness the mechanical activity of cavitation nuclei for beneficial tissue bio-effects are actively under development. The mechanical oscillations of circulating microbubbles, the most widely investigated cavitation nuclei, which may also encapsulate or shield a therapeutic agent in the bloodstream, trigger and promote localized uptake. Oscillating microbubbles can create stresses either on nearby tissue or in surrounding fluid to enhance drug penetration and efficacy in the brain, spinal cord, vasculature, immune system, biofilm or tumors. This review summarizes recent investigations that have elucidated interactions of ultrasound and cavitation nuclei with cells, the treatment of tumors, immunotherapy, the blood-brain and blood-spinal cord barriers, sonothrombolysis, cardiovascular drug delivery and sonobactericide. In particular, an overview of salient ultrasound features, drug delivery vehicles, therapeutic transport routes and pre-clinical and clinical studies is provided. Successful implementation of ultrasound and cavitation nuclei-mediated drug delivery has the potential to change the way drugs are administered systemically, resulting in more effective therapeutics and less-invasive treatments.

Tissue Targeting and Ultrasound-Targeted Microbubble Destruction Delivery of Plasmid DNA and Transfection In Vitro

Introduction

Ultrasound-targeted microbubble destruction (UTMD) has been shown a promising approach for target-specific gene delivery and treatment of many diseases in the past decade. To improve the therapeutic potential of UTMD, the gene carrier of microbubbles should possess adequate DNA condensation capability and (or) specific cell or tissue selectivity. The tissue-targeted and ultrasound-targeted cationic microbubbles were developed to meet gene therapy.

Methods

A tissue-targeted stearic acid-inserted cationic microbubbles (SCMBs) were prepared for ultrasound-targeted gene delivery. Branched PEI was modified with stearic acid and further mixed with 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and biot-1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (ammonium salt) (Biot-DSPE-PEG2000), intercellular adhesion molecule-1 (ICAM-1) antibody and plasmid DNA to prepare cationic microbubbles through ultrasonic hydration. The ICAM-1 antibody and plasmid DNA were expected to assemble to the surface of SCMBs via biotin-avidin interaction and electrostatic interaction, respectively.

Results

It was found that the SCMBs had higher zeta potential compared with neutral microbubbles (NMBs) and cationic microbubbles (CMBs). In contrast, DNA incorporated SCMBs4 showed negative potential, exhibiting good DNA-binding capacity. Confocal images showed that the HeLa cells were attached around by the SCMBs4 from the view of green fluorescence of fluorescein isothiocyanate-loaded IgG which conjugated to ICAM-1 antibody on their surface. After ultrasound treatment, HeLa cells treated with SCMBs exhibited slightly stronger red fluorescence under confocal laser scanning microscope, indicating a synergistic promotion for transfection efficiency.

Conclusions

This tissue- and ultrasound-targeted cationic microbubble demonstrated here showed a promising strategy for improving gene therapy in the future.

Development of Antibody-Modified Nanobubbles Using Fc-Region-Binding Polypeptides for Ultrasound Imaging

Ultrasound (US) imaging is a widely used imaging technique. The use of US contrast agents such as microbubbles, which consist of phospholipids and are filled with perfluorocarbon gases, has become an indispensable component of clinical US imaging, while molecular US imaging has recently attracted significant attention in combination with efficient diagnostics. The avidin–biotin interaction method is frequently used to tether antibodies to microbubbles, leading to the development of a molecular targeting US imaging agent. However, avidin still has limitations such as immunogenicity. We previously reported that lipid-based nanobubbles (NBs) containing perfluorocarbon gas are suitable for US imaging and gene delivery. In this paper, we report on the development of a novel antibody modification method for NBs using Fc-region-binding polypeptides derived from protein A/G. First, we prepared anti-CD146 antibody-modified NBs using this polypeptide, resulting in high levels of attachment to human umbilical vein endothelial cells expressing CD146. To examine their targeting ability and US imaging capability, the NBs were administered to tumor-bearing mice. The contrast imaging of antibody-modified NBs was shown to be prolonged compared with that of non-labeled NBs. Thus, this antibody modification method using an Fc-binding polypeptide may be a feasible tool for developing a next-generation antibody-modified US imaging agent.

An energy-blocking nanoparticle decorated with anti-VEGF antibody to reverse chemotherapeutic drug resistance

Multi-drug resistance (MDR) of tumor cells has greatly hindered the therapeutic efficacy of chemotherapeutic drugs, resulting in chemotherapy failure, while overexpression of ATP-binding cassette (ABC) transporters in cell membranes is the leading cause of MDR. In this study, we reported novel self-assembled triphenylphosphine-quercetin-polyethylene glycol-monoclonal antibody nanoparticles (TQ-PEG-mAb NPs) for overcoming MDR primarily through mitochondrial damage to block ATP supply to ABC transporters both in vitro and in vivo. The doxorubicin (DOX)-loaded NPs (TQ/DOX-PEG-mAb) were composed of two drugs (TQ and DOX) and an outer shielding shell of the PEG-mAb conjugate. Besides, the outer shell could be acid-responsively detached to expose the positive charge of TQ inside the NPs to enhance cellular uptake. TQ was proved to effectively induce mitochondrial damage with increased ROS levels and depolarization of mitochondrial membrane potential (MMP), leading to prominently reduced ATP supply to ABC transporters. Moreover, the involvement of the anti-vascular endothelial growth factor (VEGF) mAb was not only for efficient targeting but also for combined therapy. Consequently, TQ/DOX-PEG-mAb showed that the internalized amount of DOX was largely improved while the efflux amount was dramatically inhibited on MCF-7/ADR cells, indicating excellent reversal of DOX resistance. Importantly, the growth of DOX-resistant breast tumors was significantly inhibited with no evident systemic toxicity. Therefore, the employment of TQ-PEG-mAb is believed to be a new approach to improve the efficacy of chemotherapeutic drugs in MDR tumors.

Insulin-like growth factor binding protein related protein 1 knockdown attenuates hepatic fibrosis via the regulation of MMPs/TIMPs in mice

BACKGROUND

Previous research suggested that insulin-like growth factor binding protein related protein 1 (IGFBPrP1), as a novel mediator, contributes to hepatic fibrogenesis. Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) play an essential role in hepatic fibrogenesis by regulating homeostasis and remodeling of the extracellular matrix (ECM). However, the interaction between IGFBPrP1 and MMP/TIMP is not clear. The present study was to knockdown IGFBPrP1 to investigate the correlation between IGFBPrP1 and MMP/TIMP in hepatic fibrosis.

METHODS

Hepatic fibrosis was induced by thioacetamide (TAA) in mice. Knockdown of IGFBPrP1 expression by ultrasound-targeted microbubble destruction-mediated CMB-shRNA-IGFBPrP1 delivery, or inhibition of the Hedgehog (Hh) pathway by cyclopamine treatment, was performed in TAA-induced liver fibrosis mice. Hepatic fibrosis was determined by hematoxylin and eosin and Sirius red staining. Hepatic expression of IGFBPrP1, α-smooth muscle actin (α-SMA), transforming growth factor β 1 (TGFβ1), collagen I, MMPs/TIMPs, Sonic Hedgehog (Shh), and glioblastoma family transcription factors (Gli1) were investigated by immunohistochemical staining and Western blotting analysis.

RESULTS

We found that hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I were increased longitudinally in mice with TAA-induced hepatic fibrosis, concomitant with MMP2/TIMP2 and MMP9/TIMP1 imbalance and Hh pathway activation. Knockdown of IGFBPrP1 expression, or inhibition of the Hh pathway, reduced the hepatic expression of IGFBPrP1, TGFβ1, α-SMA, and collagen I and re-established MMP2/TIMP2 and MMP9/TIMP1 balance.

CONCLUSIONS

Our findings suggest that IGFBPrP1 knockdown attenuates liver fibrosis by re-establishing MMP2/TIMP2 and MMP9/TIMP1 balance, concomitant with the inhibition of hepatic stellate cell activation, down-regulation of TGFβ1 expression, and degradation of the ECM. Furthermore, the Hh pathway mediates IGFBPrP1 knockdown-induced attenuation of hepatic fibrosis through the regulation of MMPs/TIMPs balance.

Improving acute cardiac transplantation rejection therapy using ultrasound-targeted FK506-loaded microbubbles in rats

FK506-MBs combined with the UTMD technique increased drug concentrations in transplanted hearts and enhanced the therapeutic effect.

Morroniside protects against cerebral ischemia/reperfusion injury by inhibiting neuron apoptosis and MMP2/9 expression

The aim of the present study was to investigate the effect of morroniside against matrix metalloproteinase (MMP)2/9 and focal cerebral ischemia/reperfusion (I/R) injury in rats. A rat model of focal cerebral I/R injury rats was established and rats were administered with 30, 90 or 270 mg/kg/day morroniside for 7 days. The expression of MMP2/9 and neuronal apoptosis were assessed. In addition, the expression of active caspase-3, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were measured. The results revealed that MMP2 and MMP9 expression was upregulated and the percentage of apoptotic neurons was increased in rats with focal cerebral I/R injury compared with the control. However, treatment with morroniside significantly inhibited I/R-induced MMP2/9 expression and neuron apoptosis compared with the untreated I/R injury group. Morroniside administration also decreased the expression of active caspase-3 and increased the Bcl-2/Bax ratio compared with untreated rats with focal cerebral I/R injury. The inhibitory effect of morroniside on MMP2/9 expression and neuron apoptosis was dose dependent. In summary, the results of the present study suggest that morroniside is able to protect against cerebral I/R injury in the brain and may have potential as a therapeutic treatment for patients who have suffered a stroke.

The present and future role of ultrasound targeted microbubble destruction in preclinical studies of cardiac gene therapy

Multiple limitations for cardiac pharmacologic therapies like intolerance, individual variation in effectiveness, side effects, and high cost still remain, despite the recent progress in diagnosis and health support. Gene therapy is poised to be an attractive alternative in various ways for the future, refractory cardiac diseases being one aspect of it. As a novel therapy to deliver the objective gene to organs of living animals, ultrasound targeted microbubble destruction (UTMD) has therapeutic potential in cardiovascular disorders. UTMD, which binds microbubbles with DNA or RNA carriers into the shell and destroys the located microbubbles with low frequency and high mechanical index ultrasound can release target agents to specific organs. UTMD has the ability to transfect markedly through sonoporation, cavitation and other effects by way of intravenous injection that is minimally invasive and highly specific for gene deliverance. Here, we have summarized the present role of UTMD in pre-clinical studies of cardiac gene therapy which covers myocardial infarction, regeneration, ischaemia/reperfusion injury, hypertension, diabetic cardiomyopathy, adriamycin cardiomyopathy and some discussion for further studies.

MiR-136 controls neurocytes apoptosis by regulating Tissue Inhibitor of Metalloproteinases-3 in spinal cord ischemic injury

BACKGROUND

Spinal cord ischemia is a serious injury that threatens human health and life. Furthermore, it was widely accepted that miR-136 was mediated in the spinal injury, while whether it regulated neurocytes apoptosis in I/R-induced spinal cord injury remains unclear.

METHODS

Spinal cord ischemia injury (SCII) rats were induced by clamping the nontraumatic vascular clip on the abdominal aorta. Real-time PCR was conducted to determine the mRNA expression, and western blot was carried out to measure protein expression. TUNEL assay was used to measure cell apoptosis.

RESULTS

MiR-136 was up-regulated, while Tissue Inhibitor of Metalloproteinases-3 (TIMP3) was down-regulated in both SCII rats and hypoxic neurocytes. MiR-136 overexpression protected neurocytes against injury that induced by hypoxia. TIMP3 was the target gene of miR-136. Hypoxia supplementation decreased the expression of miR-136, promoted TIMP3 expression, and urged cell apoptosis, cells transfected with miR-136 mimic reversed the effect that induced by hypoxia, while cells co-transfected with pcDNA-TIMP3 abolished the results that induced by overexpressed miR-136.

CONCLUSION

MiR-136 regulated neurocytes apoptosis of SCII by mediating TIMP3.

A single injection of protein-loaded coacervate-gel significantly improves cardiac function post infarction

After myocardial infarction (MI), the heart undergoes fibrotic pathological remodeling instead of repair and regeneration. With multiple pathologies developing after MI, treatment using several proteins is expected to address this range of pathologies more effectively than a single-agent therapy. A factorial design of experiments study guided us to combine three complementary factors in one injection: tissue inhibitor of metalloproteinases-3 (TIMP-3) was embedded in a fibrin gel for signaling in the initial phase of the treatment, while basic fibroblast growth factor (FGF-2) and stromal cell-derived factor 1-alpha (SDF-1α) were embedded in heparin-based coacervates for sustained release and distributed within the same fibrin gel to exert their effects over a longer period. The gel was then tested in a rat model of myocardial infarction. Contractility of rat hearts treated with the protein coacervate-gel composite stabilized and slightly improved after the first week while contractility continued to decrease in rats treated with free proteins or saline over the 8 week study period. Hearts receiving the protein coacervate-gel composite treatment also exhibited reduced ventricular dilation, inflammation, fibrosis, and extracellular matrix (ECM) degradation. Revascularization, cardiomyocyte preservation, stem cell homing, and increased myocardial strain likely all contributed to the repair. This study demonstrates the potential of a multifactorial therapeutic approach in MI, using three complementary proteins delivered sequentially for comprehensive healing. The study also shows the necessity of controlled delivery for growth factors and cytokines to be an effective treatment.

Ultrasound combined with targeted cationic microbubble-mediated angiogenesis gene transfection improves ischemic heart function

The present study aimed to construct targeted cationic microbubbles (TCMBs) by synthesizing cationic microbubbles conjugated to an intercellular adhesion molecule-1 (ICAM-1) antibody, and then to use the TCMBs to deliver the angiopoietin-1 (Ang-1) gene into infarcted heart tissue using ultrasound-mediated microbubble destruction. It was hypothesized that the TCMBs would accumulate in higher numbers than non-targeted cationic microbubbles (CMBs) in the infarcted heart, and would therefore increase the efficiency of targeted Ang-1 gene transfection and promote angiogenesis. The results of the study demonstrated that the ability of TCMBs to target inflammatory endothelial cells was 18.4-fold higher than that of the CMBs in vitro. The accumulation of TCMBs was greater than that of CMBs in TNF-α-stimulated human umbilical cord veins, indicated by a 212% higher acoustic intensity. In vivo, the TCMBs specifically accumulated in the myocardial infarct area in a rabbit model. Three days after ultrasound microbubble-mediated gene transfection, Ang-1 protein expression in the TCMB group was 2.7-fold higher than that of the CMB group. Angiogenesis, the thickness of the infarct region and the heart function of the TCMB group were all significantly improved compared with those in the CMB and control groups at 4 weeks following gene transfection (all P<0.01). Therefore, the results of the current study demonstrate that ultrasound-mediated TCMB destruction effectively delivered the Ang-1 gene to the infarcted myocardium, resulting in improved cardiac morphology and function in the animal model. Ultrasound-mediated TCMB destruction is a promising strategy for improving gene therapy in the future.

Ultrasound-Targeted Microbubble Destruction for Cardiac Gene Delivery

Ultrasound targeted microbubble destruction (UTMD) is a novel technique that is used to deliver a gene or other bioactive substance to organs of living animals in a noninvasive manner. Plasmid DNA binding with cationic liposome into nanoparticles are assembled into the shell of microbubbles, which are circulated by intravenous injection. Intermittent bursts of ultrasound with low frequency and high mechanical index destroys the microbubbles and releases the nanoparticles into targeted organ to transfect local organ cells. Cell-specific promoters can be used to further enhance cell specificity. Here we describe UTMD applied to cardiac gene delivery.

Ultrasound-targeted microbubble destruction in gene therapy: A new tool to cure human diseases

Human gene therapy has made significant advances in less than two decades. Within this short period of time, gene therapy has proceeded from the conceptual stage to technology development and laboratory research, and finally to clinical trials for the treatment of a variety of deadly diseases. Cardiovascular disease, cancer, and stroke are leading causes of death worldwide. Despite advances in medical, interventional, radiation and surgical treatments, the mortality rate remains high, and the need for novel therapies is great. Gene therapy provides an efficient approach to disease treatment. Notable advances in gene therapy have been made for genetic disorders, including severe combined immune deficiency, chronic granulomatus disorder, hemophilia and blindness, as well as for acquired diseases, including cancer and neurodegenerative and cardiovascular diseases. However, lack of an efficient delivery system to target cells as well as the difficulty of sustained expression of transgenes has hindered advancements in gene therapy. Ultrasound targeted microbubble destruction (UTMD) is a promising approach for target-specific gene delivery, and it has been successfully investigated for the treatment of many diseases in the past decade. In this paper, we review UTMD-mediated gene delivery for the treatment of cardiovascular diseases, cancer and stroke.

Influence of DNA-Microbubble Coupling on Contrast Ultrasound-Mediated Gene Transfection in Muscle and Liver

BACKGROUND

Contrast ultrasound-mediated gene delivery (CUMGD) is a promising approach for enhancing gene therapy that relies on microbubble (MB) cavitation to augment complementary deoxyribonucleic acid (cDNA) transfection. The aims of this study were to determine optimal conditions for charge-coupling cDNA to MBs and to evaluate the advantages of surface loading for gene transfection in muscle and liver.

METHODS

Charge coupling of fluorescently labeled cDNA to either neutral MBs (MBN) or cationic MBs (MB+) in low- to high-ionic conditions (0.3%-1.8% NaCl) was assessed by flow cytometry. MB aggregation from cDNA coupling was determined by electrozone sensing. Tissue transfection of luciferase in murine hindlimb skeletal muscle and liver was made by CUMGD with MBN or MB+ combined with subsaturated, saturated, or supersaturated cDNA concentrations (2.5, 50, and 200 μg/10(8) MBs).

RESULTS

Charge-coupling of cDNA was detected for MB+ but not MBN. Coupling occurred over almost the entire range of ionic conditions, with a peak at 1.2% NaCl, although electrostatic interference occurred at >1.5% NaCl. DNA-mediated aggregation of MB+ was observed at ≤0.6% NaCl but did not reduce the ability to produce inertial cavitation. Transfection with CUMGD in muscle and liver was low for both MBs at subsaturation concentrations. In muscle, higher cDNA concentrations produced a 10-fold higher degree of transfection with MB+, which was approximately fivefold higher (P < .05) than that for MBN. There was no effect of DNA supersaturation. The same pattern was seen for liver except that supersaturation further increased transfection with MBN equal to that of MB+.

CONCLUSIONS

Efficient charge-coupling of cDNA to MB+ but not MBN occurs over a relatively wide range of ionic conditions without aggregation. Transfection with CUMGD is much more efficient with charge-coupling of cDNA to MBs and is not affected by supersaturation except in the liver, which is specialized for macromolecular and cDNA uptake.

Ultrasound-targeted microbubble destruction: toward a new strategy for diabetes treatment

Ultrasound-targeted microbubble destruction (UTMD) is a promising technique with an immense target-specific gene delivery potential deep inside the human body. The potential of this technique has recently been confirmed for diabetic patients. This technology allows the genes to transfer specifically into the inefficient pancreas using ultrasound energy without viral vector utilization. It has been speculated that this idea and the advent of modern gene therapy techniques could result in significant future advances. Undoubtedly, this strategy needs further investigation and many critical questions have to be answered before it can be successfully advanced. Herein, we introduce the salient features of this approach, the hurdles that must be overcome, the hopes associated with it and practical constraints to develop this method for diabetes treatment.

Exploiting the hypoxia sensitive non-coding genome for organ-specific physiologic reprogramming

In this review we highlight the role of non-coding RNAs in the development and progression of cardiac pathology and explore the possibility of disease-associated RNAs serving as targets for cardiac-directed therapeutics. Contextually, we focus on the role of stress-induced hypoxia as a driver of disease development and progression through activation of hypoxia inducible factor 1α (HIF1α) and explore mechanisms underlying HIFα function as an enforcer of cardiac pathology through direct transcriptional coupling with the non-coding transcriptome. In the interest of clarity, we will confine our analysis to cardiac pathology and focus on three defining features of the diseased state, namely metabolic, growth and functional reprogramming. It is the aim of this review to explore possible mechanisms through which HIF1α regulation of the non-coding transcriptome connects to spatiotemporal control of gene expression to drive establishment of the diseased state, and to propose strategies for the exploitation of these unique RNAs as targets for clinical therapy. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

Increased local delivery of antagomir therapeutics to the rodent myocardium using ultrasound and microbubbles

Recent developments in microRNA (miRNA) research have identified these as important mediators in the pathophysiological response upon myocardial infarction (MI). Specific miRNAs can inhibit the translation of entire groups of mRNAs, which are involved in specific processes in the pathophysiology after MI, e.g. the fibrotic, apoptotic or angiogenic response. By modulating miRNAs in the heart, these processes can be tuned to improve cardiac function. Antagomirs are effective miRNA-inhibitors, but have a low myocardial specificity and cardiac antagomir treatment therefore requires high doses, which causes side effects. In the present study, ultrasound-triggered microbubble destruction (UTMD) was studied to increase specific delivery of antagomir to the myocardium. Healthy control mice were treated with UTMD and sacrificed at 30min, 24h and 48h, after which antagomir delivery in the heart was analyzed, both qualitatively and quantitatively. Additionally, potential harmful effects of treatment were analyzed by monitoring ECG, analyzing neutrophil invasion and cell death in the heart, and measuring troponin I after treatment. Finally, UTMD was tested for delivery of antagomir in a model of ischemia-reperfusion (I/R) injury. We found that UTMD can significantly increase local antagomir delivery to the non-ischemic heart with modest side-effects like neutrophil invasion without causing apoptosis. Delivered antagomirs enter cardiomyocytes within 30min after treatment and remains there for at least 48h. Interestingly, after I/R injury antagomir already readily enters the infarcted zone and we observed no additional benefit of UTMD for antagomir delivery. This study is the first to explore cardiac antagomir delivery using UTMD. In addition, it is the first to study tissue distribution of short RNA based therapeutics (~22 base pairs) at both the cellular and organ levels after UTMD to the heart in general. In summary, UTMD provides a myocardial delivery strategy for non-vascular permeable cardiac conditions later in the I/R response or chronic conditions like cardiac hypertrophy.

Enzyme-Responsive Nanoparticles for Targeted Accumulation and Prolonged Retention in Heart Tissue after Myocardial Infarction

A method for targeting to and retaining intravenously injected nanoparticles at the site of acute myocardial infarction in a rat model is described. Enzyme-responsive peptide-polymer amphiphiles are assembled as spherical micellar nanoparticles, and undergo a morphological transition from spherical-shaped, discrete materials to network-like assemblies when acted upon by matrix metalloproteinases (MMP-2 and MMP-9), which are up-regulated in heart tissue post-myocardial infarction.

A Targeting Microbubble for Ultrasound Molecular Imaging

Rationale

Microbubbles conjugated with targeting ligands are used as contrast agents for ultrasound molecular imaging. However, they often contain immunogenic (strept)avidin, which impedes application in humans. Although targeting bubbles not employing the biotin-(strept)avidin conjugation chemistry have been explored, only a few reached the stage of ultrasound imaging in vivo, none were reported/evaluated to show all three of the following properties desired for clinical applications: (i) low degree of non-specific bubble retention in more than one non-reticuloendothelial tissue; (ii) effective for real-time imaging; and (iii) effective for acoustic quantification of molecular targets to a high degree of quantification. Furthermore, disclosures of the compositions and methodologies enabling reproduction of the bubbles are often withheld.

Objective

To develop and evaluate a targeting microbubble based on maleimide-thiol conjugation chemistry for ultrasound molecular imaging.

Methods and Results

Microbubbles with a previously unreported generic (non-targeting components) composition were grafted with anti-E-selectin F(ab’)₂ using maleimide-thiol conjugation, to produce E-selectin targeting microbubbles. The resulting targeting bubbles showed high specificity to E-selectin in vitro and in vivo. Non-specific bubble retention was minimal in at least three non-reticuloendothelial tissues with inflammation (mouse heart, kidneys, cremaster). The bubbles were effective for real-time ultrasound imaging of E-selectin expression in the inflamed mouse heart and kidneys, using a clinical ultrasound scanner. The acoustic signal intensity of the targeted bubbles retained in the heart correlated strongly with the level of E-selectin expression (|r|≥0.8), demonstrating a high degree of non-invasive molecular quantification.

Conclusions

Targeting microbubbles for ultrasound molecular imaging, based on maleimide-thiol conjugation chemistry and the generic composition described, may possess properties (i)–(iii) desired for clinical applications.

Diagnostic and therapeutic research on ultrasound microbubble/nanobubble contrast agents (Review)

The contrast enhanced imaging function of ultrasound contrast agents (UCAs) has been extensively investigated using physical acoustic signatures. It has a number of novel applications, including tissue‑specific molecular imaging and multi‑modal imaging. In addition there are numerous other therapeutic applications of UCAs, for example as vehicles for drug or gene delivery. These uses are discussed, as well as the acoustically‑induced biological effects, including ultrasound targeted microbubble destruction (UTMD). This review also explores the considerations for the safe use of UCA from an acoustic standpoint. The scope of the application of UCA has markedly expanded in recent years, and it is a rapidly growing field of medical research. The current article reviews recent advances in the diagnostic and therapeutic applications of ultrasound microbubble/nanobubble contrast agents.

Development of fluorous lipid-based nanobubbles for efficiently containing perfluoropropane

Nano-/microbubbles are expected not only to function as ultrasound contrast agents but also as ultrasound-triggered enhancers in gene and drug delivery. Notably, nanobubbles have the ability to pass through tumor vasculature and achieve passive tumor targeting. Thus, nanobubbles would be an attractive tool for use as ultrasound-mediated cancer theranostics. However, the amounts of gas carried by nanobubbles are generally lower than those carried by microbubbles because nanobubbles have inherently smaller volumes. In order to reduce the injection volume and to increase echogenicity, it is important to develop nanobubbles with higher gas content. In this study, we prepared 5 kinds of fluoro-lipids and used these reagents as surfactants to generate "Bubble liposomes", that is, liposomes that encapsulate nanobubbles such that the lipids serve as stabilizers between the fluorous gas and water phases. Bubble liposome containing 1-stearoyl-2-(18,18-difluoro)stearoyl-sn-glycero-3-phosphocholine carried 2-fold higher amounts of C3F8 compared to unmodified Bubble liposome. The modified Bubble liposome also exhibited increased echogenicity by ultrasonography. These results demonstrated that the inclusion of fluoro-lipid is a promising tool for generating nanobubbles with increased efficiency of fluorous gas carrier.

Targeting MMP-2 to treat ischemic heart injury

Matrix metalloproteinase (MMPs) are long understood to be involved in remodeling of the extracellular matrix. However, over the past decade, it has become clear that one of the most ubiquitous MMPs, MMP-2, has numerous intracellular targets in cardiac myocytes. Notably, MMP-2 proteolyzes components of the sarcomere, and its intracellular activity contributes to ischemia-reperfusion injury of the heart. Together with the well documented role played by MMPs in the myocardial remodeling that occurs following myocardial infarction, this has led to great interest in targeting MMPs to treat cardiac ischemic injury. In this review we will describe the expanding understanding of intracellular MMP-2 biology, and how this knowledge may lead to improved treatments for ischemic heart injury. We also critically review the numerous preclinical studies investigating the effects of MMP inhibition in animal models of myocardial infarction and ischemia-reperfusion injury, as well as the recent clinical trials that are part of the effort to translate these results into clinical practice. Acknowledging the disappointing results of past clinical trials of MMP inhibitors for other diseases, we discuss the need for carefully designed preclinical and clinical studies to avoid mistakes that have been previously made. We conclude that inhibition of MMPs, and in particular MMP-2, shows promise as a therapy to prevent the progression from ischemic injury to heart failure. However, it is critical that the full breadth of MMP-2 biology be taken into account as such therapies are developed.