Use of cationic microbubbles targeted to P-selectin to improve ultrasound-mediated gene transfection of hVEGF165 to the ischemic myocardium

Experimental Study on the Compatibility and Characteristics of a Dual-Target Microbubble Loaded with Anti-miR-33

Objective

To prepare a new type of dual-target microbubble loaded with anti-miR-33 (ANM33).

Methods

Carrier core nanobubbles (NBs) were prepared by thin film hydration, and microbubbles loaded with PM1 (PCNBs) were prepared by grafting DSPE-PEG2000-maleimide-PM1 onto the NB surface. ANM33 was connected via electrostatic adsorption and covalent bonding, and hyaluronic acid (HA) was covalently connected. PM1 and HA were the targets, and ANM33 was the intervention drug. To evaluate the general physical and chemical properties of the prepared dual-target microbubbles loaded with ANM33 (HA-PANBs), we observed their morphology, particle size and surface potential while monitoring their stability and in vitro imaging ability, evaluated their toxic effect on cells and verified their ability to target cells.

Results

HA-PANBs had a regular morphology and good stability. The average particle size measured by a Malvern potentiometer was 1421.75±163.23 nm, and the average surface potential was −5.51±1.87 mV. PM1 and ANM33 were effectively connected to the NBs. The PM1, ANM33, and HA binding reached 89.0±1.1%, 65.02±5.0%, and 61.4±3.5%, respectively, and the maximum binding reached 2 µg, 5 µg, and 7 µg/10⁸ microbubbles, respectively. HA-PANBs had no obvious toxic effects on cells, and their ability to continuously enhance imaging in vitro persisted for more than 15 minutes, obviously targeting foam cells in the early stage of AS.

Conclusion

HA-PANBs are ideal ultrasound contrast agents. The successful, firm connection of PM1 and HA to the NBs significantly increased the amount of carried ANM33. When microbubbles prepared with 2:4:7 PM1:ANM33:HA were used as a contrast agent, they had a high ANM33 carrying capacity, stable physical properties, and significantly enhanced imaging and targeting of foam cells in the early stage of AS.

Ultrasound and Microbubbles for Targeted Drug Delivery to the Lung Endothelium in ARDS: Cellular Mechanisms and Therapeutic Opportunities

Acute respiratory distress syndrome (ARDS) is characterized by increased permeability of the alveolar–capillary membrane, a thin barrier composed of adjacent monolayers of alveolar epithelial and lung microvascular endothelial cells. This results in pulmonary edema and severe hypoxemia and is a common cause of death after both viral (e.g., SARS-CoV-2) and bacterial pneumonia. The involvement of the lung in ARDS is notoriously heterogeneous, with consolidated and edematous lung abutting aerated, less injured regions. This makes treatment difficult, as most therapeutic approaches preferentially affect the normal lung regions or are distributed indiscriminately to other organs. In this review, we describe the use of thoracic ultrasound and microbubbles (USMB) to deliver therapeutic cargo (drugs, genes) preferentially to severely injured areas of the lung and in particular to the lung endothelium. While USMB has been explored in other organs, it has been under-appreciated in the treatment of lung injury since ultrasound energy is scattered by air. However, this limitation can be harnessed to direct therapy specifically to severely injured lungs. We explore the cellular mechanisms governing USMB and describe various permutations of cargo administration. Lastly, we discuss both the challenges and potential opportunities presented by USMB in the lung as a tool for both therapy and research.

Ultrasonic microbubble VEGF gene delivery improves angiogenesis of senescent endothelial progenitor cells

The therapeutic effects of ultrasonic microbubble transfection (UMT)-based vascular endothelial growth factor 165 (VEGF165) gene delivery on young and senescent endothelial progenitor cells (EPCs) were investigated. By UMT, plasmid DNA (pDNA) can be delivered into both young EPCs and senescent EPCs. In the UMT groups, higher pDNA-derived protein expression was found in senescent EPCs than in young EPCs. Consistent with this finding, a higher intracellular level of pDNA copy number was detected in senescent EPCs, with a peak at the 2-h time point post UMT. Ultrasonic microbubble delivery with or without VEGF improved the angiogenic properties, including the proliferation and/or migration activities, of senescent EPCs. Supernatants from young and senescent EPCs subjected to UMT-mediated VEGF transfection enhanced the proliferation and migration of human aortic endothelial cells (HAECs), and the supernatant of senescent EPCs enhanced proliferation more strongly than the supernatant from young EPCs. In the UMT groups, the stronger enhancing effect of the supernatant from senescent cells on HAEC proliferation was consistent with the higher intracellular VEGF pDNA copy number and level of protein production per cell in the supernatant from senescent cells in comparison to the supernatant from young EPCs. Given that limitations for cell therapies are the inadequate number of transplanted cells and/or insufficient cell angiogenesis, these findings provide a foundation for enhancing the therapeutic angiogenic effect of cell therapy with senescent EPCs in ischaemic cardiovascular diseases.

Phospholipid-coated targeted microbubbles for ultrasound molecular imaging and therapy

Phospholipid-coated microbubbles are ultrasound contrast agents that, when functionalized, adhere to specific biomarkers on cells. In this concise review, we highlight recent developments in strategies for targeting the microbubbles and their use for ultrasound molecular imaging (UMI) and therapy. Recently developed novel targeting strategies include magnetic functionalization, triple targeting, and the use of several new ligands. UMI is a powerful technique for studying disease progression, diagnostic imaging, and monitoring of therapeutic responses. Targeted microbubbles (tMBs) have been used for the treatment of cardiovascular diseases and cancer, with therapeutics either coadministered or loaded onto the tMBs. Regardless of which disease was treated, the use of tMBs always resulted in a better therapeutic outcome than non-tMBs when compared in vitro or in vivo.

Effects of leptin-modified human placenta-derived mesenchymal stem cells on angiogenic potential and peripheral inflammation of human umbilical vein endothelial cells (HUVECs) after X-ray radiation

Combined radiation-wound injury (CRWI) is characterized by blood vessel damage and pro-inflammatory cytokine deficiency. Studies have identified that the direct application of leptin plays a significant role in angiogenesis and inflammation. We established a sustained and stable leptin expression system to study the mechanism. A lentivirus method was employed to explore the angiogenic potential and peripheral inflammation of irradiated human umbilical vein endothelial cells (HUVECs). Leptin was transfected into human placenta-derived mesenchymal stem cells (HPMSCs) with lentiviral vectors. HUVECs were irradiated by X-ray at a single dose of 20 Gy. Transwell migration assay was performed to assess the migration of irradiated HUVECs. Based on the Transwell systems, co-culture systems of HPMSCs and irradiated HUVECs were established. Cell proliferation was measured by cell counting kit-8 (CCK-8) assay. The secretion of pro-inflammatory cytokines (human granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-1α, IL-6, and IL-8) was detected by enzyme-linked immunosorbent assay (ELISA). The expression of pro-angiogenic factors (vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF)) mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR) assay. Relevant molecules of the nuclear factor-κB (NF-κB) and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways were detected by western blot assay. Results showed that leptin-modified HPMSCs (HPMSCs/ leptin) exhibited better cell proliferation, migration, and angiogenic potential (expressed more VEGF and bFGF). In both the single HPMSCs/leptin and the co-culture systems of HPMSCs/leptin and irradiated HUVECs, the increased secretion of pro-inflammatory cytokines (human GM-CSF, IL-1α, and IL-6) was associated with the interaction of the NF-κB and JAK/STAT signaling pathways. We conclude that HPMSCs/leptin could promote angiogenic potential and peripheral inflammation of HUVECs after X-ray radiation.

Ultrasonic irradiation and SonoVue microbubbles-mediated RNA interference targeting PRR11 inhibits breast cancer cells proliferation and metastasis, but promotes apoptosis

The present study compared the effects of ultrasonic irradiation and SonoVue microbubbles (US) or Lipofectamine 3000 on the transfection of small interfering RNA for PRR11 (siPRR11) and Proline-rich protein 11 (PRR11) overexpression plasmid into breast cancer cells. SiPRR11 and PRR11 overexpression plasmid were transfected into breast cancer MCF7 cells mediated by US and Lipofectamine 3000. PRR11 expressions in breast cancer and normal tissues were determined using Gene Expression Profiling Interactive Analysis (GEPIA). The viability, proliferation, migration, invasion and apoptosis of breast cancer cells were respectively measured by MTT assay, clone formation assay, scratch wound-healing assay, Transwell assay and flow cytometry. PRR11 and epithelial-to-mesenchymal transition (EMT)-related and apoptosis-related (B-cell lymphoma 2, Bcl-2; Bcl-2-associated protein X, Bax) proteins' expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot as appropriate. As ultrasonic intensity increased, the viability of MCF7 cells was decreased. Results from GEPIA suggested that PRR11 was up-regulated in breast cancer. Silencing PRR11 mediated by US showed a higher efficiency than by Lipofectamine 3000. SiPRR11 transfected by Lipofectamine 3000 suppressed cells growth and metastasis, while promoted cell apoptosis. Moreover, E-cadherin (E-cad) and Bax expressions were high but N-cadherin (N-cad), Snail and Bcl-2 expressions were low. However, overexpressed PRR11 caused the opposite effects. More importantly, transfection of siPRR11 and PRR11 overexpression plasmid using US had a higher efficacy than using Lipofectamine 3000. US transfection of PRR11 siRNA showed better effects on inhibiting breast cancer progression. The current findings contribute to a novel treatment for breast cancer.

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.

Enhanced Proliferation of Endothelial Progenitor Cells Post-Ultrasonic Microbubble Transfection Is Plasmid DNA Size Dependent and Contributed by Interleukin-6 Generation

We investigated whether ultrasonic microbubble transfection (UMT) would enhance the transfection of large-sized luciferase plasmids (5.6, 9.2 and 33 kb) and biological impacts. Porcine venous blood endothelial progenitor cells (EPCs) were cultured in a medium containing plasmid DNA (pDNA) of different sizes followed by UMT and functional assays. Real-time polymerase chain reaction was conducted to investigate the effects of transfection of pDNA on multiple molecules central to endothelial function. The results indicated enhanced luciferase expression after UMT but the enhancement declined with increase in the size of the plasmid. UMT of pDNAs sized 5.6 and 9.2 kb into EPCs led to significant enhancement of proliferation. The interleukin-6 (IL-6) secreted from UMT of EPCs also increased in the 5.6- and 9.2-kb pDNA groups. Treatment of the transfected EPCs with anti-IL-6 antibody neutralized the proliferation. In conclusion, UMT of pDNAs sized 5.6 and 9.2 kb into EPCs increased the secretion of IL-6, which in turn enhanced cell proliferation.

The better effects of microbubble ultrasound transfection of miR-940 on cell proliferation inhibition and apoptosis promotion in human cervical cancer cells

Purpose

Cervical cancer is the second leading cause of women’s cancer-related death. MiR-940 has been reported as a critical factor in various cancers. Based on the high transfection efficiency and low side effect, the clinical application of microbubble ultrasound contrast agent in gene treatment has attracted a widespread attention. In this study, we determined the mechanism of miR-940 inhibiting cell proliferation and cycle procession, and promoting cell apoptosis in cervical cancer Hela cells. In addition, we compared the effects of different transfection methods, including liposome, microbubble, ultrasound, and microbubble coupled with ultrasound.

Patients and methods

MTT assay, PI staining, and Annexin-Ⅴ/PI staining assays were, respectively, performed to evaluate cell proliferation status, cell cycle progression, and apoptosis status. RT-PCR and Western blot were conducted to measure the levels of cell cycle- and apoptosis-related factors, and the phosphorylation levels of PI3K and Akt.

Results

Results showed that the overexpression of miR-940 inhibited cell proliferation, blocked cell cycle, and promoted apoptosis by regulating cell cycle-related factors (such as inhibited Cyclin D1 and CDK4) and apoptosis-related factors (such as promoted Puma and Bax, inhibited Bcl-2 and Cleaved caspase9), and inhibiting the phosphorylation and activation of PI3K/AKT pathway. Among all of them, miR-940 transfected with microbubble and ultrasound showed the greatest changes.

Conclusion

It provides evidence that miR-940 could be a wonderful biomarker and treatment agent for cervical cancer, and microbubble ultrasound would have more wide application in the clinical treatment of cancers.

Applications of Ultrasound to Stimulate Therapeutic Revascularization

Many pathological conditions are characterized or caused by the presence of an insufficient or aberrant local vasculature. Thus, therapeutic approaches aimed at modulating the caliber and/or density of the vasculature by controlling angiogenesis and arteriogenesis have been under development for many years. As our understanding of the underlying cellular and molecular mechanisms of these vascular growth processes continues to grow, so too do the available targets for therapeutic intervention. Nonetheless, the tools needed to implement such therapies have often had inherent weaknesses (i.e., invasiveness, expense, poor targeting, and control) that preclude successful outcomes. Approximately 20 years ago, the potential for using ultrasound as a new tool for therapeutically manipulating angiogenesis and arteriogenesis began to emerge. Indeed, the ability of ultrasound, especially when used in combination with contrast agent microbubbles, to mechanically manipulate the microvasculature has opened several doors for exploration. In turn, multiple studies on the influence of ultrasound-mediated bioeffects on vascular growth and the use of ultrasound for the targeted stimulation of blood vessel growth via drug and gene delivery have been performed and published over the years. In this review article, we first discuss the basic principles of therapeutic ultrasound for stimulating angiogenesis and arteriogenesis. We then follow this with a comprehensive cataloging of studies that have used ultrasound for stimulating revascularization to date. Finally, we offer a brief perspective on the future of such approaches, in the context of both further research development and possible clinical translation.