Role of specific endocytic pathways in electrotransfection of cells

Silver Nanoparticles (AgNPs) Uptake by Caveolae-Dependent Endocytosis is Responsible for Their Selective Effect Towards Castration Resistant Prostate Cancer

Purpose

Castration Resistant Prostate Cancer (CRPC) is characterized by poor prognosis and limited therapeutic options. AgNPs functionalized with glucose (G-AgNPs) were observed cytotoxic to CRPC cell lines (PC-3 and Du-145) and not LNCaP. This study aims to evaluate AgNPs and G-AgNPs' uptake mechanisms in these cells and understand their role in the selective effect against CRPC cells.

Methods

Uptake of AgNPs and G-AgNPs was assessed through transmission electron microscopy (TEM). A microRNA (miRNAs) analysis approach was used to uncover the main molecular differences responsible for the endocytic mechanisms' regulation. Caveolin (Cav) 1 and 2 mRNA and protein levels were assessed in the three cell lines. Caveolae-dependent endocytosis was inhibited with genistein or siCav1- and siCav2- in PC-3 and Du-145 and resazurin assay was used to evaluate viability after AgNPs and G-AgNPs administration. Caveolae-dependent endocytosis was induced with Cav1+ and Cav2+ plasmids in LNCaP, resazurin assay was used to evaluate viability after AgNPs and G-AgNPs administration and TEM to assess their location.

Results

AgNPs and G-AgNPs were not uptaked by LNCaP. miRNA analysis revealed 37 upregulated and 90 downregulated miRNAs. Functional enrichment analysis of miRNAs' targets resulted in enrichment of terms related to endocytosis and caveolae. We observed that Cav1 and Cav2 are not expressed in LNCaP. Inhibiting caveolae-dependent endocytosis in Du-145 and PC-3 led to a significative reduction of cytotoxic capacity of AgNPs and G-AgNPs and induction of caveolae-dependent endocytosis in LNCaP lead to a significative increase as well as their uptake by cells.

Conclusion

This study shows the potential of these AgNPs as a new therapeutic approach directed to CRPC patients, uncovers caveolae-dependent endocytosis as the uptake mechanism of these AgNPs and highlights deregulation of Cav1 and Cav2 expression as a key difference in hormone sensitive and resistant PCa cells which may be responsible for drug resistance.

A comprehensive comparison of DNA and RNA vaccines

Nucleic acid technology has revolutionized vaccine development, enabling rapid design and production of RNA and DNA vaccines for prevention and treatment of diseases. The successful deployment of mRNA and plasmid DNA vaccines against COVID-19 has further validated the technology. At present, mRNA platform is prevailing due to its higher efficacy, while DNA platform is undergoing rapid evolution because it possesses unique advantages that can potentially overcome the problems associated with the mRNA platform. To help understand the recent performances of the two vaccine platforms and recognize their clinical potentials in the future, this review compares the advantages and drawbacks of mRNA and DNA vaccines that are currently known in the literature, in terms of development timeline, financial cost, ease of distribution, efficacy, safety, and regulatory approval of products. Additionally, the review discusses the ongoing clinical trials, strategies for improvement, and alternative designs of RNA and DNA platforms for vaccination.

DNA Electrotransfer Regulates Molecular Functions in Skeletal Muscle

Background

Tissues, such as skeletal muscle, have been targeted for the delivery of plasmid DNA (pDNA) encoding vaccines and therapeutics. The application of electric pulses (electroporation or electrotransfer) increases cell membrane permeability to enhance plasmid delivery and expression. However, the molecular effects of DNA electrotransfer on the muscle tissue are poorly characterized.

Materials and Methods

Four hours after intramuscular plasmid electrotransfer, we evaluated gene expression changes by RNA sequencing. Differentially expressed genes were analyzed by gene ontology (GO) pathway enrichment analysis.

Results

GO analysis highlighted many enriched molecular functions. The terms regulated by pulse application were related to muscle stress, the cytoskeleton and inflammation. The terms regulated by pDNA injection were related to a DNA-directed response and its control. Several terms regulated by pDNA electrotransfer were similar to those regulated by pulse application. However, the terms related to pDNA injection differed, focusing on entry of the plasmid into the cells and intracellular trafficking.

Conclusion

Each muscle stimulus resulted in specific regulated molecular functions. Identifying the unique intrinsic molecular changes driven by intramuscular DNA electrotransfer will aid in the design of preventative and therapeutic gene therapies.

Enhanced intracellular uptake of an albumin fusion protein in cancer cells by its forced cell surface recruitment

Albumin fusion or conjugation is a well-established technique for tumor delivery and is mainly mediated by albumin-induced caveolae-dependent endocytosis. We report that caveolae-dependent endocytic signaling activated by human serum albumin (HSA) is not sufficiently strong to induce cellular uptake, mainly due to its electrostatic repulsion from the negatively charged cell surface sulfated glycosaminoglycans (GAGs), and fusion of the cell-surface-retained protein with HSA is an effective strategy to activate the HSA-induced endocytic signal, thereby improving its intracellular uptake. In this study, human lactoferrin (hLF), a protein that accumulates on the cell surface along with GAGs, was selected for delivery into human lung adenocarcinoma PC-14 cells. When added exogenously, hLF-fused HSA (hLF-HSA) was successfully endocytosed, whereas the simultaneous addition of HSA and hLF did not result in endocytosis, indicating less efficient activation of endocytic signaling by HSA alone and the importance of its fusion. Importantly, the treatment of cells with chlorate, a known inhibitor of GAG sulfation, dramatically suppressed the endocytosis of hLF-HSA owing to the loss of the hLF-GAG interaction. Therefore, the cell-surface localization of HSA imposed by fusion with the cell-surface-retained protein enhances its binding to the relevant receptor, which improves intracellular delivery as an albumin-fusion platform.

Fabrication of a Dual-Targeted Liposome-Coated Mesoporous Silica Core-Shell Nanoassembly for Targeted Cancer Therapy

Nanoparticles have been suggested as drug-delivery systems for chemotherapeutic drugs to allow for controlled drug release profiles and selectivity to target cancer cells. In addition, nanoparticles can be used for the in situ generation and amplification of reactive oxygen species (ROS), which have been shown to be a promising strategy for cancer treatment. Thus, a targeted nanoscale drug-delivery platform could be used to synergistically improve cancer treatment by the action of chemotherapeutic drugs and ROS generation. Herein, we propose a promising chemotherapy strategy where the drug-loaded nanoparticles generate high doses of ROS together with the loaded ROS-generating chemotherapeutic drugs, which can damage the mitochondria and activate cell death, potentiating the therapeutic outcome in cancer therapy. In the present study, we have developed a dual-targeted drug-delivery nanoassembly consisting of a mesoporous silica core loaded with the chemotherapeutic, ROS-generating drug, paclitaxel (Px), and coated with a liposome layer for controlled drug release. Two different lung cancer-targeting ligands, folic acid and peptide GE11, were used to target the overexpressed nonsmall lung cancer receptors to create the final nanoassembly (MSN@Px) L-GF. Upon endocytosis by the cancer cells, the liposome layer was degraded by the intracellular lipases, and the drug was rapidly released at a rate of 65% within the first 20 h. In vitro studies confirmed that this nanoassembly was 8-fold more effective in cancer therapy compared to the free drug Px.

Uptake of H-ferritin by Glioblastoma stem cells and its impact on their invasion capacity

PURPOSE

Iron acquisition is key to maintaining cell survival and function. Cancer cells in general are considered to have an insatiable iron need. Iron delivery via the transferrin/transferrin receptor pathway has been the canonical iron uptake mechanism. Recently, however, our laboratory and others have explored the ability of ferritin, particularly the H-subunit, to deliver iron to a variety of cell types. Here, we investigate whether Glioblastoma (GBM) initiating cells (GICs), a small population of stem-like cells, are known for their iron addiction and invasive nature acquire exogenous ferritin, as a source of iron. We further assess the functional impact of ferritin uptake on the invasion capacity of the GICs.

METHODS

To establish that H-ferritin can bind to human GBM, tissue-binding assays were performed on samples collected at the time of surgery. To interrogate the functional consequences of H-ferritin uptake, we utilized two patient-derived GIC lines. We further describe H-ferritin's impact on GIC invasion capacity using a 3D invasion assay.

RESULTS

H-ferritin bound to human GBM tissue at the amount of binding was influenced by sex. GIC lines showed uptake of H-ferritin protein via transferrin receptor. FTH1 uptake correlated with a significant decrease in the invasion capacity of the cells. H-ferritin uptake was associated with a significant decrease in the invasion-related protein Rap1A.

CONCLUSION

These findings indicate that extracellular H-ferritin participates in iron acquisition to GBMs and patient-derived GICs. The functional significance of the increased iron delivery by H-ferritin is a decreased invasion capacity of GICs potentially via reduction of Rap1A protein levels.

Next-generation poly-L-histidine formulations for miRNA mimic delivery

Many diseases, especially cancer, are caused by the abnormal expression of non-coding microRNAs (miRNAs), which regulate gene expression, leading to the development of miRNA-based therapeutics. Synthetic miRNA inhibitors have shown promising efficacy in blocking the activity of aberrant miRNAs that are upregulated in disease-specific pathologies. On the other hand, miRNAs that aid in preventing certain diseases and are reduced in expression in the disease state need different strategies. To tackle this, miRNA mimics, which mimic the activity of endogenous miRNAs, can be delivered for those miRNAs downregulated in different disease states. However, the delivery of miRNA mimics remains a challenge. Here, we report a cationic polylactic-co-glycolic acid (PLGA)-poly-L-histidine delivery system to deliver miRNA mimics. We chose miR-34a mimics as a proof of concept for miRNA delivery. miR-34a-loaded PLGA-poly-L-histidine nanoparticles (NPs) were formulated and biophysically characterized to analyze the structural properties of miRNA mimic-loaded NPs. In vitro efficacy was determined by investigating miR-34a and downstream target levels and performing cell viability and apoptosis assays. We confirmed in vivo efficacy through prolonged survival of miR-34a NP-treated A549-derived xenograft mice treated intratumorally. The results of these studies establish PLGA-poly-L-histidine NPs as an effective delivery system for miRNA mimics for treating diseases characterized by downregulated miRNAs.

Therapeutic Applications of Mesenchymal Stem Cell Loaded with Gold Nanoparticles for Regenerative Medicine

In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton's jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton's jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton's jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton's jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H⁺-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton's jelly MSCs.

Tolerogenic Nanovaccine for Prevention and Treatment of Autoimmune Encephalomyelitis

Herein, a tolerogenic nanovaccine is developed and tested on an animal model of multiple sclerosis. The nanovaccine is constructed to deliver the self-antigen, myelin oligodendrocyte glycoprotein (MOG) peptide, and dexamethasone on an abatacept-modified polydopamine core nanoparticle (AbaLDPN-MOG). AbaLDPN-MOG can target dendritic cells and undergo endocytosis followed by trafficking to lysosomes. AbaLDPN-MOG blocks the interaction between CD80/CD86 and CD28 in antigen-presenting cells and T cells, leading to decreased interferon gamma secretion. The subcutaneous administration of AbaLDPN-MOG to mice yields significant biodistribution to lymph nodes and, in experimental-autoimmune encephalomyelitis (EAE) model mice, increases the integrity of the myelin basic sheath and minimizes the infiltration of immune cells. EAE mice are treated with AbaLDPN-MOG before or after injection of the autoantigen, MOG. Preimmunization of AbaLDPN-MOG before the injection of MOG completely blocks the development of clinical symptoms. Early treatment with AbaLDPN-MOG at three days after injection of MOG also completely blocks the development of symptoms. Notably, treatment of EAE symptom-developed mice with AbaLDPN-MOG significantly alleviates the symptoms, indicating that the nanovaccine has therapeutic effects. Although AbaLDPN is used for MOG peptide delivery in the EAE model, the concept of AbaLDPN can be widely applied for the prevention and alleviation of other autoimmune diseases.

Insight into the role of clathrin-mediated endocytosis inhibitors in SARS-CoV-2 infection

Emergence of SARS-CoV-2 variants warrants sustainable efforts to upgrade both the diagnostic and therapeutic protocols. Understanding the details of cellular and molecular basis of the virus-host cell interaction is essential for developing variant-independent therapeutic options. The internalization of SARS-CoV-2, into lung epithelial cells, is mediated by endocytosis, especially clathrin-mediated endocytosis (CME). Although vaccination is the gold standard strategy against viral infection, selective inhibition of endocytic proteins, complexes, and associated adaptor proteins may present a variant-independent therapeutic strategy. Although clathrin and/or dynamins are the most important proteins involved in CME, other endocytic mechanisms are clathrin and/or dynamin independent and rely on other proteins. Moreover, endocytosis implicates some subcellular structures, like plasma membrane, actin and lysosomes. Also, physiological conditions, such as pH and ion concentrations, represent an additional factor that mediates these events. Accordingly, endocytosis related proteins are potential targets for small molecules that inhibit endocytosis-mediated viral entry. This review summarizes the potential of using small molecules, targeting key proteins, participating in clathrin-dependent and -independent endocytosis, as variant-independent antiviral drugs against SARS-CoV-2 infection. The review takes two approaches. The first outlines the potential role of endocytic inhibitors in preventing endocytosis-mediated viral entry and its mechanism of action, whereas in the second computational analysis was implemented to investigate the selectivity of common inhibitors against endocytic proteins in SARS-CoV-2 endocytosis. The analysis revealed that remdesivir, methyl-β-cyclodextrin, rottlerin, and Bis-T can effectively inhibit clathrin, HMG-CoA reductase, actin, and dynamin I GTPase and are more potent in inhibiting SARS-CoV-2 than chloroquine. CME inhibitors for SARS-CoV-2 infection remain understudied.

Liposomes Loaded with Amaranth Unsaponifiable Matter and Soybean Lunasin Prevented Melanoma Tumor Development Overexpressing Caspase-3 in an In Vivo Model

The objective of this study was to assess the effectiveness of liposomes loaded with soybean lunasin and amaranth unsaponifiable matter (UM + LunLip) as a source of squalene in the prevention of melanoma skin cancer in an allograft mice model. Tumors were induced by transplanting melanoma B16-F10 cells into the mice. The most effective treatments were those including UM + LunLip, with no difference between the lunasin concentrations (15 or 30 mg/kg body weight); however, these treatments were statistically different from the tumor-bearing untreated control (G3) (p < 0.05). The groups treated with topical application showed significant inhibition (68%, p < 0.05) compared to G3. The groups treated with subcutaneous injections showed significant inhibition (up to 99%, p < 0.05) in G3. During tumor development, UM + LunLip treatments under-expressed Ki-67 (0.2-fold compared to G3), glycogen synthase kinase-3β (0.1-fold compared to G3), and overexpressed caspase-3 (30-fold compared to G3). In addition, larger tumors showed larger necrotic areas (38% with respect to the total tumor) (p < 0.0001). In conclusion, the UM + LunLip treatment was effective when applied either subcutaneously or topically in the melanoma tumor-developing groups, as it slowed down cell proliferation and activated apoptosis.

Psychotropic drugs interaction with the lipid nanoparticle of COVID-19 mRNA therapeutics

The messenger RNA (mRNA) vaccines for COVID-19, Pfizer-BioNTech and Moderna, were authorized in the US on an emergency basis in December of 2020. The rapid distribution of these therapeutics around the country and the world led to millions of people being vaccinated in a short time span, an action that decreased hospitalization and death but also heightened the concerns about adverse effects and drug-vaccine interactions. The COVID-19 mRNA vaccines are of particular interest as they form the vanguard of a range of other mRNA therapeutics that are currently in the development pipeline, focusing both on infectious diseases as well as oncological applications. The Vaccine Adverse Event Reporting System (VAERS) has gained additional attention during the COVID-19 pandemic, specifically regarding the rollout of mRNA therapeutics. However, for VAERS, absence of a reporting platform for drug-vaccine interactions left these events poorly defined. For example, chemotherapy, anticonvulsants, and antimalarials were documented to interfere with the mRNA vaccines, but much less is known about the other drugs that could interact with these therapeutics, causing adverse events or decreased efficacy. In addition, SARS-CoV-2 exploitation of host cytochrome P450 enzymes, reported in COVID-19 critical illness, highlights viral interference with drug metabolism. For example, patients with severe psychiatric illness (SPI) in treatment with clozapine often displayed elevated drug levels, emphasizing drug-vaccine interaction.

Improved Delivery Performance of n-Butylidenephthalide-Polyethylene Glycol-Gold Nanoparticles Efficient for Enhanced Anti-Cancer Activity in Brain Tumor

n-butylidenephthalide (BP) has been verified as having the superior characteristic of cancer cell toxicity. Furthermore, gold (Au) nanoparticles are biocompatible materials, as well as effective carriers for delivering bio-active molecules for cancer therapeutics. In the present research, Au nanoparticles were first conjugated with polyethylene glycol (PEG), and then cross-linked with BP to obtain PEG-Au-BP nanodrugs. The physicochemical properties were characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) to confirm the combination of PEG, Au, and BP. In addition, both the size and structure of Au nanoparticles were observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), where the size of Au corresponded to the results of DLS assay. Through in vitro assessments, non-transformed BAEC and DBTRG human glioma cells were treated with PEG-Au-BP drugs to investigate the tumor-cell selective cytotoxicity, cell uptake efficiency, and mechanism of endocytic routes. According to the results of MTT assay, PEG-Au-BP was able to significantly inhibit DBTRG brain cancer cell proliferation. Additionally, cell uptake efficiency and potential cellular transportation in both BAEC and DBTRG cell lines were observed to be significantly higher at 2 and 24 h. Moreover, the mechanisms of endocytosis, clathrin-mediated endocytosis, and cell autophagy were explored and determined to be favorable routes for BAEC and DBTRG cells to absorb PEG-Au-BP nanodrugs. Next, the cell progression and apoptosis of DBTRG cells after PEG-Au-BP treatment was investigated by flow cytometry. The results show that PEG-Au-BP could remarkably regulate the DBTRG cell cycle at the Sub-G1 phase, as well as induce more apoptotic cells. The expression of apoptotic-related proteins in DBTRG cells was determined through Western blotting assay. After treatment with PEG-Au-BP, the apoptotic cascade proteins p21, Bax, and Act-caspase-3 were all significantly expressed in DBTRG brain cancer cells. Through in vivo assessments, the tissue morphology and particle distribution in a mouse model were examined after a retro-orbital sinus injection containing PEG-Au-BP nanodrugs. The results demonstrate tissue integrity in the brain (forebrain, cerebellum, and midbrain), heart, liver, spleen, lung, and kidney, as they did not show significant destruction due to PEG-Au-BP treatment. Simultaneously, the extended retention period for PEG-Au-BP nanodrugs was discovered, particularly in brain tissue. The above findings identify PEG-Au-BP as a potential nanodrug for brain cancer therapies.

Spatiotemporal tracking of the transport of RNA nano-drugs: from transmembrane to intracellular delivery

The popularity of RNA nanoparticles (RNPs) has risen rapidly during the past decade due to the development of RNA nanotechnology. Understanding the fast dynamic process of cell entry and intracellular delivery of RNPs is essential for the design of intelligent therapeutic RNA nano-drugs and mRNA vaccines.How the interaction between the membrane and target ligand of RNPs influences the cell entry, and how the dynamic mechanism of RNPs takes place in different organelles remain ill-defined. Herein, the cell entry of Antimir21-RNP-Apt is monitored using a force tracing technique with a high spatiotemporal resolution at the single particle level, the specific interaction of Apt and EGFR promotes the cell entry efficiency and achieves long-lasting curative effects. Furthermore, the intracellular delivery pathway through different organelles is discovered using fluorescence tracking, and the low motility in early endosomes and the high motility in late endosomes are analyzed. This report provides key strategies for engineering RNA nanomedicines and facilitating clinical translation.

Influence of Liposomes’ and Lipoplexes’ Physicochemical Characteristics on Their Uptake Rate and Mechanisms by the Placenta

Pregnant women are still considered as drug orphans. Developing new medications for pregnancy complications is an urgent need. Nanomedicines seem to be a promising approach to control the biodistribution of drugs to ensure both the mother’s and the fetus’ safety. Understanding the interaction between nanoparticles and the placental barrier is a key factor to the success of the development of nanomedicines for pregnant women. In this study, we evaluated the behavior of fluorescent PEGylated liposomes and lipoplexes in human placental tissue using in vitro and ex vivo models, BeWo cell culture and suspended villous placental explants, respectively. Fluorescent based analytical tools such as Fluorescence activated cells sorting (FACS), confocal microscopy and HPLC coupled to fluorescence detection were used to assess liposomes penetration and their endocytosis mechanisms in the placenta. First, no influence of the PEGylation density was observed on the cellular internalization of liposomal formulations using both models. The comparison between neutral and cationic liposomes exhibits a significant higher internalization of the cationic formulation compared to the neutral ones. In addition, the HPLC quantification of the fluorescent liposomes in human villous explants demonstrated an increase of cationic liposomes uptake with increasing incubation concentrations. Similar uptake of cationic liposomes and lipoplexes, containing the same cationic lipid, the DMAPAP but with an overall neutral surface charge, was observed and evidenced the higher effect of composition than charge surface on trophoblast penetration. Moreover, both cationic liposomes and lipoplexes exhibited an endocytosis mechanism of internalization via pathways implicating dynamin. These data highlight the key role of the liposome’s lipid composition and the possibility to modulate their internalization in the placenta by adjusting their design.

Dynamic Distribution of ASIC1a Channels and Other Proteins within Cells Detected through Fractionation

Proteins in eukaryotic cells reside in different cell compartments. Many studies require the specific localization of proteins and the detection of any dynamic changes in intracellular protein distribution. There are several methods available for this purpose that rely on the fractionation of the different cell compartments. Fractionation protocols have evolved since the first use of a centrifuge to isolate organelles. In this study, we described a simple method that involves the use of a tabletop centrifuge and different detergents to obtain cell fractions enriched in cytosolic (Cyt), plasma membrane (PM), membranous organelle (MO), and nuclear (Nu) proteins and identify the proteins in each fraction. This method serves to identify transmembrane proteins such as channel subunits as well as PM-embedded or weakly associated proteins. This protocol uses a minute amount of cell material and typical equipment present in laboratories, and it takes approximately 3 h. The process was validated using endogenous and exogenous proteins expressed in the HEK293T cell line that were targeted to each compartment. Using a specific stimulus as a trigger, we showed and quantified the shuttling of a protein channel (ASIC1a, acid sensing ion channel) from the MO fraction to the PM fraction and the shuttling of a kinase from a cytosolic location to a nuclear location.

Syndecan-4 Is a Key Facilitator of the SARS-CoV-2 Delta Variant's Superior Transmission

Emerging SARS-CoV-2 variants pose threats to vaccination campaigns against COVID-19. Being more transmissible than the original virus, the SARS-CoV-2 B.1.617 lineage, named the Delta variant, swept through the world in 2021. The mutations in the Delta's spike protein shift the protein towards a net positive electrostatic potential. To understand the key molecular drivers of the Delta infection, we investigate the cellular uptake of the Delta spike protein and Delta spike-bearing SARS-CoV-2 pseudoviruses. Specific in vitro modification of ACE2 and syndecan expression enabled us to demonstrate that syndecan-4, the syndecan isoform abundant in the lung, enhances the transmission of the Delta variant by attaching its mutated spike glycoprotein and facilitating its cellular entry. Compared to the wild-type spike, the Delta one shows a higher affinity towards heparan sulfate proteoglycans than towards ACE2. In addition to attachment to the polyanionic heparan sulfate chains, the Delta spike's molecular interactions with syndecan-4 also involve syndecan-4's cell-binding domain that mediates cell-to-cell adhesion. Regardless of the complexity of these interactions, exogenously added heparin blocks Delta's cellular entry as efficiently as syndecan-4 knockdown. Therefore, a profound understanding of the molecular mechanisms underlying Delta infections enables the development of molecularly targeted yet simple strategies to reduce the Delta variant's spread.

ICAM-1 Targeted Drug Combination Nanoparticles Enhanced Gemcitabine-Paclitaxel Exposure and Breast Cancer Suppression in Mouse Models

Despite the availability of molecularly targeted treatments such as antibodies and small molecules for human epidermal growth factor receptor 2 (HER2), hormone receptor (HR), and programmed death-ligand 1 (PD-L1), limited treatment options are available for advanced metastatic breast cancer (MBC), which constitutes ~90% mortality. Many of these monotherapies often lead to drug resistance. Novel MBC-targeted drug-combination therapeutic approaches that may reduce resistance are urgently needed. We investigated intercellular adhesion molecule-1 (ICAM-1), which is abundant in MBC, as a potential target to co-localize two current drug combinations, gemcitabine (G) and paclitaxel (T), assembled in a novel drug-combination nanoparticle (GT DcNP) form. With an ICAM-1-binding peptide (referred to as LFA1-P) coated on GT DcNPs, we evaluated the role of the LFA1-P density in breast cancer cell localization in vitro and in vivo. We found that 1–2% LFA1-P peptide incorporated on GT DcNPs provided optimal cancer cell binding in vitro with ~4× enhancement compared to non-peptide GT DcNPs. The in vivo probing of GT DcNPs labeled with a near-infrared marker, indocyanine green, in mice by bio-imaging and G and T analyses indicated LFA1-P enhanced drug and GT DcNP localization in breast cancer cells. The target/healthy tissue (lung/gastrointestinal (GI)) ratio of particles increased by ~60× compared to the non-ligand control. Collectively, these data indicated that LFA1 on GT DcNPs may provide ICAM-1-targeted G and T drug combination delivery to advancing MBC cells found in lung tissues. As ICAM-1 is generally expressed even in breast cancers that are triple-negative phenotypes, which are unresponsive to inhibitors of nuclear receptors or HER2/estrogen receptor (ER) agents, ICAM-1-targeted LFA1-P-coated GT DcNPs should be considered for clinical development to improve therapeutic outcomes of MBCs.

DNA/RNA heteroduplex oligonucleotide technology for regulating lymphocytes in vivo

Manipulating lymphocyte functions with gene silencing approaches is promising for treating autoimmunity, inflammation, and cancer. Although oligonucleotide therapy has been proven to be successful in treating several conditions, efficient in vivo delivery of oligonucleotide to lymphocyte populations remains a challenge. Here, we demonstrate that intravenous injection of a heteroduplex oligonucleotide (HDO), comprised of an antisense oligonucleotide (ASO) and its complementary RNA conjugated to α-tocopherol, silences lymphocyte endogenous gene expression with higher potency, efficacy, and longer retention time than ASOs. Importantly, reduction of Itga4 by HDO ameliorates symptoms in both adoptive transfer and active experimental autoimmune encephalomyelitis models. Our findings reveal the advantages of HDO with enhanced gene knockdown effect and different delivery mechanisms compared with ASO. Thus, regulation of lymphocyte functions by HDO is a potential therapeutic option for immune-mediated diseases.

Novel suction-based in vivo cutaneous DNA transfection platform

This work reports a suction-based cutaneous delivery method for in vivo DNA transfection. Following intradermal Mantoux injection of plasmid DNA in a rat model, a moderate negative pressure is applied to the injection site, a technique similar to Chinese báguàn and Middle Eastern hijama cupping therapies. Strong GFP expression was demonstrated with pEGFP-N1 plasmids where fluorescence was observed as early as 1 hour after dosing. Modeling indicates a strong correlation between focal strain/stress and expression patterns. The absence of visible and/or histological tissue injury contrasts with current in vivo transfection systems such as electroporation. Specific utility was demonstrated with a synthetic SARS-CoV-2 DNA vaccine, which generated host humoral immune response in rats with notable antibody production. This method enables an easy-to-use, cost-effective, and highly scalable platform for both laboratorial transfection needs and clinical applications for nucleic acid–based therapeutics and vaccines.

Delivery Capacity and Anticancer Ability of the Berberine-Loaded Gold Nanoparticles to Promote the Apoptosis Effect in Breast Cancer

Simple Summary

In this research, we aimed to evaluate the biological effects of physically gold nanoparticle-collagen nanocarrier incorporated with alkaloid berberine (Au-Col-BB) on non-transformed bovine aortic endothelial cells (BAEC) and Her-2 breast cancer cell lines through in vitro and in vivo assessments. Au-Col-BB showed better cytotoxicity, as well as significantly induced cell apoptosis in Her-2 cancer cells compared with normal cells (non-transformed BAEC). Further, Au-Col-BB also demonstrated better anti-cancer capacity for inhibiting cell growth in Her-2 tumor-bearing mice. In brief, we confirmed that the Au-Col-BB nanocarrier could be a potential nanodrug for increasing the efficiency of specific therapeutic effects in breast cancer disease.

Abstract

Gold nanoparticles (AuNPs) were fabricated with biocompatible collagen (Col) and then conjugated with berberine (BB), denoted as Au-Col-BB, to investigate the endocytic mechanisms in Her-2 breast cancer cell line and in bovine aortic endothelial cells (BAEC). Owing to the superior biocompatibility, tunable physicochemical properties, and potential functionalization with biomolecules, AuNPs have been well studied as carriers of biomolecules for diseases and cancer therapeutics. Composites of AuNPs with biopolymer, such as fibronectin or Col, have been revealed to increase cell proliferation, migration, and differentiation. BB is a natural compound with impressive health benefits, such as lowering blood sugar and reducing weight. In addition, BB can inhibit cell proliferation by modulating cell cycle progress and autophagy, and induce cell apoptosis in vivo and in vitro. In the current research, BB was conjugated on the Col-AuNP composite (“Au-Col”). The UV-Visible spectroscopy and infrared spectroscopy confirmed the conjugation of BB on Au-Col. The particle size of the Au-Col-BB conjugate was about 227 nm, determined by dynamic light scattering. Furthermore, Au-Col-BB was less cytotoxic to BAEC vs. Her-2 cell line in terms of MTT assay and cell cycle behavior. Au-Col-BB, compared to Au-Col, showed greater cell uptake capacity and potential cellular transportation by BAEC and Her-2 using the fluorescence-conjugated Au-Col-BB. In addition, the clathrin-mediated endocytosis and cell autophagy seemed to be the favorite endocytic mechanism for the internalization of Au-Col-BB by BAEC and Her-2. Au-Col-BB significantly inhibited cell migration in Her-2, but not in BAEC. Moreover, apoptotic cascade proteins, such as Bax and p21, were expressed in Her-2 after the treatment of Au-Col-BB. The tumor suppression was examined in a model of xenograft mice treated with Au-Col-BB nanovehicles. Results demonstrated that the tumor weight was remarkably reduced by the treatment of Au-Col-BB. Altogether, the promising findings of Au-Col-BB nanocarrier on Her-2 breast cancer cell line suggest that Au-Col-BB may be a good candidate of anticancer drug for the treatment of human breast cancer.

A modified density gradient proteomic-based method to analyze endolysosomal proteins in cardiac tissue

The importance of lysosomes in cardiac physiology and pathology is well established, and evidence for roles in calcium signaling is emerging. We describe a label-free proteomics method suitable for small cardiac tissue biopsies based on density-separated fractionation, which allows study of endolysosomal (EL) proteins. Density gradient fractions corresponding to tissue lysate; sarcoplasmic reticulum (SR), mitochondria (Mito) (1.3 g/mL); and EL with negligible contamination from SR or Mito (1.04 g/mL) were analyzed using Western blot, enzyme activity assay, and liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis (adapted discontinuous Percoll and sucrose differential density gradient). Kyoto Encyclopedia of Genes and Genomes, Reactome, Panther, and Gene Ontology pathway analysis showed good coverage of RAB proteins and lysosomal cathepsins (including cardiac-specific cathepsin D) in the purified EL fraction. Significant EL proteins recovered included catalytic activity proteins. We thus present a comprehensive protocol and data set of guinea pig atrial EL organelle proteomics using techniques also applicable for non-cardiac tissue.

Aluminum particles generated during millisecond electric pulse application enhance adenovirus-mediated gene transfer in L929 cells

Gene electrotransfer is an attractive method of non-viral gene delivery. However, the mechanism of DNA penetration across the plasma membrane is widely discussed. To explore this process for even larger structures, like viruses, we applied various combinations of short/long and high/low-amplitude electric pulses to L929 cells, mixed with a human adenovirus vector expressing GFP. We observed a transgene expression increase, both in the number of GFP-converted cells and GFP levels, when we added a low-voltage/millisecond-pulse treatment to the adenovirus/cell mixture. This increase, reflecting enhanced virus penetration, was proportional to the applied electric field amplitude and pulse number, but was not associated with membrane permeabilization, nor to direct cell modifications. We demonstrated that this effect is mainly due to adenovirus particle interactions with aggregated aluminum particles released from energized electrodes. Indeed, after centrifugation of the pulsed viral suspension and later on addition to cells, the activity was found mainly associated with the aluminum aggregates concentrated in the lower fraction and was proportional to generated quantities. Overall, this work focused on the use of electrotransfer to facilitate the adenovirus entry into cell, demonstrating that modifications of the penetrating agent can be more important than modifications of the target cell for transfer efficacy.

Role of Endocytosis Pathways in Electropermeablization of MCF7 Cells Using Low Voltage and High Frequency Electrochemotherapy

Objective

The cell membrane is a major barrier for delivery of hydrophilic drugs and molecules into the cells. Although low voltage and high frequency electric fields (LVHF) are proposed to overcome the cell membrane barrier, the mechanism of membrane permeabilization is unclear. The aim of study is to investigate endocytosis pathways as a possible mechanism for enhancing uptake of bleomycin by LVHF.

Materials and Methods

In this experimental study, MCF-7 cells were exposed to bleomycin or to electric fields with various strengths (10-80 V/cm), frequency of 5 kHz, 4000 electric pulse and 100 µs duration in the presence and absence of three endocytosis inhibitors-chlorpromazine (Cpz), amiloride (Amilo) and genistein (Geni). We determined the efficiency of these chemotherapeutic agents in each group.

Results

LVHF, depending on the intensity, induced different endocytosis pathways. Electric field strengths of 10 and 20 V/cm stimulated the macropinocytosis route. Clathrin-mediated endocytosis was observed at electric field intensities of 10, 30, 60 and 70 V/cm, whereas induction of caveolae-mediated endocytosis was observed only at the lowest electric field intensity (10 V/cm).

Conclusion

The results of this study imply that LVHF can induce different endocytosis pathways in MCF-7 cells, which leads to an increase in bleomycin uptake.

Cholesterol Sequestration from Caveolae/Lipid Rafts Enhances Cationic Liposome-Mediated Nucleic Acid Delivery into Endothelial Cells

Delivering nucleic acids into the endothelium has great potential in treating vascular diseases. However, endothelial cells, which line the vasculature, are considered as sensitive in nature and hard to transfect. Low transfection efficacies in endothelial cells limit their potential therapeutic applications. Towards improving the transfection efficiency, we made an effort to understand the internalization of lipoplexes into the cells, which is the first and most critical step in nucleic acid transfections. In this study, we demonstrated that the transient modulation of caveolae/lipid rafts mediated endocytosis with the cholesterol-sequestrating agents, nystatin, filipin III, and siRNA against Cav-1, which significantly increased the transfection properties of cationic lipid-(2-hydroxy-N-methyl-N,N-bis(2-tetradecanamidoethyl)ethanaminium chloride), namely, amide liposomes in combination with 1,2-Dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) (AD Liposomes) in liver sinusoidal endothelial cells (SK-Hep1). In particular, nystatin was found to be highly effective with 2–3-fold enhanced transfection efficacy when compared with amide liposomes in combination with Cholesterol (AC), by switching lipoplex internalization predominantly through clathrin-mediated endocytosis and macropinocytosis.

Periodic Mesoporous Ionosilica Nanoparticles for Green Light Photodynamic Therapy and Photochemical Internalization of siRNA

We report periodic mesoporous ionosilica nanoparticles (PMINPs) as versatile nano-objects for imaging, photodynamic therapy (PDT), and efficient adsorption and delivery of small interfering RNA (siRNA) into breast cancer cells. In order to endow these nanoparticles with PDT and siRNA photochemical internalization (PCI) properties, a porphyrin derivative was integrated into the ionosilica framework. For this purpose, we synthesized PMINPs via hydrolysis-cocondensation procedures from oligosilylated ammonium and porphyrin precursors. The formation of these nano-objects was proved by transmission electron microscopy. The formed nanoparticles were then thoroughly characterized via solid-state NMR, nitrogen sorption, dynamic light scattering, and UV-vis and fluorescence spectroscopies. Our results indicate the formation of highly porous nanorods with a length of 108 ± 9 nm and a width of 54 ± 4 nm. A significant PDT effect of type I mechanism (95 ± 2.8% of cell death) was observed upon green light irradiation in nanoparticle-treated breast cancer cells, while the blue light irradiation caused a significant phototoxic effect in non-treated cells. Furthermore, PMINPs formed stable complexes with siRNA (up to 24 h), which were efficiently internalized into the cells after 4 h of incubation mostly with the energy-dependent endocytosis process. The PCI effect was obvious with green light irradiation and successfully led to 83 ± 1.1% silencing of the luciferase gene in luciferase-expressing breast cancer cells, while no gene silencing effect was observed with blue light irradiation. The present work highlights the high potential of porphyrin-doped PMINPs as multifunctional nanocarriers for nucleic acids, such as siRNA, with a triple ability to perform imaging, PDT, and PCI.

Droplet microarrays for cell culture: effect of surface properties and nanoliter culture volume on global transcriptomic landscape

The development of novel chemically developed and physically defined surfaces and environments for cell culture and screening is important for various biological applications. The Droplet microarray (DMA) platform based on hydrophilic-superhydrophobic patterning enables high-throughput cellular screening in nanoliter volumes and on various biocompatible surfaces. Here we performed phenotypic and transcriptomic analysis of HeLa-CCL2 cells cultured on DMA, with a goal to analyze cellular response on different surfaces and culture volumes down to 3 nL, compared with conventional cell culture platforms. Our results indicate that cells cultured on four tested substrates: nanostructured nonpolymer, rough and smooth variants of poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) polymer and poly(thioether) dendrimer are compatible with cells grown in Petri dish. Cells cultured on nanostructured nonpolymer coating exhibited the closet transcriptomic resemblance to that of cells grown in Petri dish. Analysis of cells cultured in 100, 9, and 3 nL media droplets on DMA indicated that all but cells grown in 3 nL volumes had unperturbed viability with minimal alterations in the transcriptome compared with 96-well plate. Our findings demonstrate the applicability of DMA for cell-based assays and highlight the possibility of establishing regular cell culture on various biomaterial-coated substrates and in nanoliter volumes, along with routinely used cell culture platforms.

Gene transfer by electroporation with high frequency bipolar pulses in vitro

High-frequency bipolar pulses (HF-BP) have been demonstrated to be efficient for membrane permeabilization and irreversible electroporation. Since membrane permeabilization has been achieved using HF-BP pulses we hypothesized that with these pulses we can also achieve successful gene electrotransfer (GET). Three variations of bursts of 2 µs bipolar pulses with 2 µs interphase delay were applied in HF-BP protocols. We compared transfection efficiency of monopolar micro and millisecond pulses and HF-BP protocols at various plasmid DNA (pDNA) concentrations on CHO - K1 cells. GET efficiency increased with increasing pDNA concentration. Overall GET obtained by HF-BP pulse protocols was comparable to overall GET obtained by longer monopolar pulse protocols. Our results, however, suggest that although we were able to achieve similar percent of transfected cells, the number of pDNA copies that were successfully transferred into cells seemed to be higher when longer monopolar pulses were used. Interestingly, we did not observe any direct correlation between fluorescence intensity of pDNA aggregates formed on cell membrane and transfection efficiency. The results of our study confirmed that we can achieve successful GET with bipolar microsecond i. e. HF-BP pulses, although at the expense of higher pDNA concentrations.

Sub-10 nm Substrate Roughness Promotes the Cellular Uptake of Nanoparticles by Upregulating Endocytosis-Related Genes

Nanosubstrate engineering is an established approach for modulating cellular responses, but it remains infrequently exploited to facilitate the intracellular delivery of nanoparticles (NPs). We report nanoscale roughness of the extracellular environment as a critical parameter for regulating the cellular uptake of NPs. After seeding cells atop a substrate that contains randomly immobilized gold NPs (termed AuNP-S) with sub-10 nm surface roughness, we demonstrate that such cells internalize up to ∼100-fold more poly(ethylene glycol)-coated AuNPs (Au@PEG NPs) than those cells seeded on a conventional flat culture plate. Our result is generalizable to 4 different cell types and Au@PEG NPs modified with 13 different hydrocarbyl functional groups. Conditioning cells to AuNP-S not only leads to upregulation of clathrin- and integrin-related genes, but also supports elevated uptake of Au@PEG NPs via clathrin-mediated endocytosis. Our data suggest a simple and robust method for boosting the intracellular delivery of nanomedicines by nanosubstrate engineering.

Strategies for Delivering Nanoparticles across Tumor Blood Vessels

Nanoparticle transport across tumor blood vessels is a key step in nanoparticle delivery to solid tumors. However, the specific pathways and mechanisms of this nanoparticle delivery process are not fully understood. Here, the biological and physical characteristics of the tumor vasculature and the tumor microenvironment are explored and how these features affect nanoparticle transport across tumor blood vessels is discussed. The biological and physical methods to deliver nanoparticles into tumors are reviewed and paracellular and transcellular nanoparticle transport pathways are explored. Understanding the underlying pathways and mechanisms of nanoparticle tumor delivery will inform the engineering of safer and more effective nanomedicines for clinical translation.

Nanoparticles that do not compete with endogenous ligands - Molecular characterization in vitro, acute safety in canine, and interspecies pharmacokinetics modeling to humans

A vast majority, if not all of the receptor-mediated drug delivery systems utilize nanoparticles that are conjugated to physiological mimic ligands, with testing restricted to in vitro and rodent models. In this report, we present for the first time, a full spectrum characterization of transferrin receptor 1 (TfR1)-targeted polymeric nanoparticles (abbreviated, P2Ns-GA) that do not compete with endogenous transferrin, and serve as a versatile platform for oral drug delivery. Based on endocytosis inhibitors and receptor knockdown, the cellular uptake of P2Ns-GA is clathrin-mediated and dependent on TfR1 expression, but other trafficking mechanisms, particularly those involving caveolae/lipid rafts, can also play a role. The utility of P2Ns-GA in promoting the oral bioavailability of encapsulated compounds is demonstrated with a hydrophobic polyphenol, urolithin A (UA). When compared against plain UA or UA in ligand-free nanoparticles, UA-loaded P2Ns-GA led to markedly higher plasma concentrations among healthy canines, with no adverse health effects observed after oral dosing. Finally, a semi-mechanistic pharmacokinetic model was developed using both rat and dog datasets to quantitatively evaluate the effect of P2Ns-GA on oral bioavailability of UA. The model was allometrically scaled to humans to simulate clinical pharmacokinetics of plain UA and UA-loaded P2Ns-GA following oral administration.

A statistical framework for determination of minimal plasmid copy number required for transgene expression in mammalian cells

Plasmid DNA (pDNA) has been widely used for non-viral gene delivery. After pDNA molecules enter a mammalian cell, they may be trapped in subcellular structures or degraded by nucleases. Only a fraction of them can function as templates for transcription in the nucleus. Thus, an important question is, what is the minimal amount of pDNA molecules that need to be delivered into a cell for transgene expression? At present, it is technically a challenge to experimentally answer the question. To this end, we developed a statistical framework to establish the relationship between two experimentally quantifiable factors - average copy number of pDNA per cell among a group of cells after transfection and percent of the cells with transgene expression. The framework was applied to the analysis of electrotransfection under different experimental conditions in vitro. We experimentally varied the average copy number per cell and the electrotransfection efficiency through changes in extracellular pDNA dose, electric field strength, and pulse number. The experimental data could be explained or predicted quantitatively by the statistical framework. Based on the data and the framework, we could predict that the minimal number of pDNA molecules in the nucleus for transgene expression was on the order of 10. Although the prediction was dependent on the cell and experimental conditions used in the study, the framework may be generally applied to analysis of non-viral gene delivery.

Cyclodextrin-Based Nanostructure Efficiently Delivers siRNA to Glioblastoma Cells Preferentially via Macropinocytosis

Small interfering ribonucleic acid (siRNA) has the potential to revolutionize therapeutics since it can knockdown very efficiently the target protein. It is starting to be widely used to interfere with cell infection by HIV. However, naked siRNAs are unable to get into the cell, requiring the use of carriers to protect them from degradation and transporting them across the cell membrane. There is no information about which is the most efficient endocytosis route for high siRNA transfection efficiency. One of the most promising carriers to efficiently deliver siRNA are cyclodextrin derivatives. We have used nanocomplexes composed of siRNA and a β-cyclodextrin derivative, AMC6, with a very high transfection efficiency to selectively knockdown clathrin heavy chain, caveolin 1, and p21 Activated Kinase 1 to specifically block clathrin-mediated, caveolin-mediated and macropinocytosis endocytic pathways. The main objective was to identify whether there is a preferential endocytic pathway associated with high siRNA transfection efficiency. We have found that macropinocytosis is the preferential entry pathway for the nanoparticle and its associated siRNA cargo. However, blockade of macropinocytosis does not affect AMC6-mediated transfection efficiency, suggesting that macropinocytosis blockade can be functionally compensated by an increase in clathrin- and caveolin-mediated endocytosis.

High-throughput continuous-flow microfluidic electroporation of mRNA into primary human T cells for applications in cellular therapy manufacturing

Implementation of gene editing technologies such as CRISPR/Cas9 in the manufacture of novel cell-based therapeutics has the potential to enable highly-targeted, stable, and persistent genome modifications without the use of viral vectors. Electroporation has emerged as a preferred method for delivering gene-editing machinery to target cells, but a major challenge remaining is that most commercial electroporation machines are built for research and process development rather than for large-scale, automated cellular therapy manufacturing. Here we present a microfluidic continuous-flow electrotransfection device designed for precise, consistent, and high-throughput genetic modification of target cells in cellular therapy manufacturing applications. We optimized our device for delivery of mRNA into primary human T cells and demonstrated up to 95% transfection efficiency with minimum impact on cell viability and expansion potential. We additionally demonstrated processing of samples comprising up to 500 million T cells at a rate of 20 million cells/min. We anticipate that our device will help to streamline the production of autologous therapies requiring on the order of 10[Formula: see text]-10[Formula: see text] cells, and that it is well-suited to scale for production of trillions of cells to support emerging allogeneic therapies.

Microfluidic production of protein loaded chimeric stealth liposomes

The addition of polyethylene glycol (PEG) on the surface of liposomes increases their circulation time when administered intravenously. However, the inclusion of PEG using PEGylated phospholipids could result in a possible micelles formation. The development of chimeric systems mixing synthetic biocompatible and biodegradable PEG-containing copolymers with lipids is a strategy to obtain as well PEGylated liposomes. Microfluidics is an innovative manufacturing technology easy to scale up that presents high reproducibility, low batch-to-batch variation, and better control over particles characteristics. Taking advantage of this technique, in this research work, chimeric stealth liposomes were produced mixing five different synthesized methoxy-poly(ethylene glycol)-block-poly(δ-decalactone) (mPEG-PDL, varying in polymer length) with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol. The obtained chimeric formulations were around 150 nm in size with a narrow distribution and an almost neutral surface charge. Ovalbumin (OVA) was used as a model protein to evaluate the loading potential reaching an encapsulation efficiency of 41 ± 4%. The prepared systems showed no cytotoxicity in vitro on THP-1 cell with an uptake up to 89 ± 4% after 3 h. Finally, protein integrity after encapsulation was confirmed with DQ-OVA. In this work, we demonstrated that using microfluidics, it is possible to produce stable and highly protein-loaded chimeric stealth liposomes with good physicochemical characteristics, no toxicity, protein integrity, and effective uptake by endocytosis.

Inhibition of Caspases Improves Non-Viral T Cell Receptor Editing

T cell receptor (TCR) knockout is a critical step in producing universal chimeric antigen receptor T cells for cancer immunotherapy. A promising approach to achieving the knockout is to deliver the CRISPR/Cas9 system into cells using electrotransfer technology. However, clinical applications of the technology are currently limited by the low cell viability. In this study, we attempt to solve the problem by screening small molecule drugs with an immortalized human T cell line, Jurkat clone E6-1, for inhibition of apoptosis. The study identifies a few caspase inhibitors that could be used to simultaneously enhance the cell viability and the efficiency of plasmid DNA electrotransfer. Additionally, we show that the enhancement could be achieved through knockdown of caspase 3 expression in siRNA treated cells, suggesting that the cell death in electrotransfer experiments was caused mainly by caspase 3-dependent apoptosis. Finally, we investigated if the caspase inhibitors could improve TCR gene-editing with electrotransferred ribonucleoprotein, a complex of Cas9 protein and a T cell receptor-α constant (TRAC)-targeting single guide RNA (sgRNA). Our data showed that inhibition of caspases post electrotransfer could significantly increase cell viability without compromising the TCR disruption efficiency. These new findings can be used to improve non-viral T cell engineering.

Enhancing Cell Viability and Efficiency of Plasmid DNA Electrotransfer Through Reducing Plasma Membrane Permeabilization

Background

Pulsed electric field has been widely used to facilitate molecular cargo transfer into cells. However, the cell viability is often decreased when trying to increase the electrotransfer efficiency. We hypothesize that the decrease is due to electropermeabilization of cell membrane that disrupts homeostasis of intracellular microenvironment. Thus, a reduction in the membrane permeabilization may increase the cell viability.

Materials and Methods

Different compounds were supplemented into the pulsing buffer prior to electrotransfer for reduction of cell membrane damage. Extent of the damage was quantified by leakiness of the membrane to a fluorescent dye, calcein, preloaded into cells. At 24 hours post electrotransfer, cell viability and electrotransfer efficiency were quantified with flow cytometry.

Results

The cell viability could be substantially increased by supplementation of either type B gelatin or bovine serum albumin (BSA), without compromising the electrotransfer efficiency. The supplementation also decreased the amount of calcein leaking out of the cells, suggesting that the improvement in cell viability was due to the reduction in electrotransfer-induced membrane damage.

Conclusion

Data from the study demonstrate that type B gelatin and BSA can be used as inexpensive supplements for improving cell viability in electrotransfer.

Aggregatibacter actinomycetemcomitans LtxA Hijacks Endocytic Trafficking Pathways in Human Lymphocytes

Leukotoxin (LtxA), from oral pathogen Aggregatibacter actinomycetemcomitans, is a secreted membrane-damaging protein. LtxA is internalized by β2 integrin LFA-1 (CD11a/CD18)-expressing leukocytes and ultimately causes cell death; however, toxin localization in the host cell is poorly understood and these studies fill this void. We investigated LtxA trafficking using multi-fluor confocal imaging, flow cytometry and Rab5a knockdown in human T lymphocyte Jurkat cells. Planar lipid bilayers were used to characterize LtxA pore-forming activity at different pHs. Our results demonstrate that the LtxA/LFA-1 complex gains access to the cytosol of Jurkat cells without evidence of plasma membrane damage, utilizing dynamin-dependent and presumably clathrin-independent mechanisms. Upon internalization, LtxA follows the LFA-1 endocytic trafficking pathways, as identified by co-localization experiments with endosomal and lysosomal markers (Rab5, Rab11A, Rab7, and Lamp1) and CD11a. Knockdown of Rab5a resulted in the loss of susceptibility of Jurkat cells to LtxA cytotoxicity, suggesting that late events of LtxA endocytic trafficking are required for toxicity. Toxin trafficking via the degradative endocytic pathway may culminate in the delivery of the protein to lysosomes or its accumulation in Rab11A-dependent recycling endosomes. The ability of LtxA to form pores at acidic pH may result in permeabilization of the endosomal and lysosomal membranes.

Multiple cytosolic DNA sensors bind plasmid DNA after transfection

Mammalian cells express a variety of nucleic acid sensors as one of the first lines of defense against infection. Despite extensive progress in the study of sensor signaling pathways during the last decade, the detailed mechanisms remain unclear. In our previous studies, we reported increased type I interferon expression and the upregulation of several proposed cytosolic DNA sensors after transfection of several tumor cell types with plasmid DNA (pDNA). In the present study, we sought to reveal the early events in the cytosolic sensing of this nucleic acid in a myoblast cell line. We demonstrated that DNA-dependent activator of interferon regulatory factors/Z-DNA binding protein 1 (DAI/ZBP1) bound plasmid DNA in the cytosol within 15 minutes of transfection and at consistent levels for 4 h. Interferon activated gene 204 protein (p204) and DEAH box helicase 9 (DHX9) also bound pDNA, peaking 15 and 30 min respectively. Plasmid DNA was not detectably bound by DEAD box helicase 60 (DDX60) protein, despite a similar level of mRNA upregulation to DAI/ZBP1, or by cyclic GMP-AMP synthase (cGAS), despite its presence in the cell cytosol. Taken together, these results indicate several DNA sensors may participate and cooperate in the complex process of cytosolic DNA sensing.

Enhancement of drug electrotransfer by extracellular plasmid DNA

Electroporation is a widely established method for molecular delivery across electric field perturbed plasma membrane. It can be used as a non-viral DNA transfection method, or as a way to achieve small molecule delivery to or extraction from cells. We examined the possibility of combining the DNA delivery to the cells with small molecule transport across electroporated plasma membrane. The results show that the presence of DNA in electroporation medium increases the extraction of fluorescent dye calcein from calcein-AM loaded cells as well as the delivery of small-molecule drug bleomycin to the cells. We propose that these results may have implications in enhanced drug delivery using electroporation both in vivo and in clinics.

Developing a Bright NIR-II Fluorophore with Fast Renal Excretion and Its Application in Molecular Imaging of Immune Checkpoint PD-L1

Fluorescence imaging in the second near-infrared (NIR-II) window holds impressive advantages of enhanced penetration depth and improved signal-to-noise ratio. Bright NIR-II fluorophores with renal excretion ability and low tissue accumulation are favorable for in vivo molecular imaging applications as they can render the target-mediated molecular imaging process easily distinguishable. Here, a probe (anti-PD-L1-BGP6) comprising a fluorophore (IR-BGP6) covalently bonded to the programmed cell death ligand-1 monoclonal antibody (PD-L1 mAb) for molecular imaging of immune checkpoint PD-L1 (a targeting site upregulated in various tumors for cancer imaging) in the NIR-II window is reported. Through molecular optimization, the bright NIR-II fluorophore IR-BGP6 with fast renal excretion (≈91% excretion in general through urine within the first 10 h postinjection) is developed. The conjugate anti-PD-L1-BGP6 succeeds in profiling PD-L1 expression and realizes efficient noninvasive molecular imaging in vivo, achieving a tumor to normal tissue (T/NT) signal ratio as high as ≈9.5. Compared with the NIR-II fluorophore with high nonspecific tissue accumulation, IR-BGP6 derived PD-L1 imaging significantly enhances the molecular imaging performance, serving as a strong tool for potentially studying underlying mechanism of immunotherapy. The work provides rationales to design renal-excreted NIR-II fluorophores and illustrate their advantages for in vivo molecular imaging.

Ultrastructural Analysis of Vesicular Transport in Electrotransfection

Emerging evidence from various studies indicates that plasmid DNA (pDNA) is internalized by cells through an endocytosis-like process when it is used for electrotransfection. To provide morphological evidence of the process, we investigated ultrastructures in cells that were associated with the electrotransfected pDNA, using immunoelectron microscopy. The results demonstrate that four endocytic pathways are involved in the uptake of the pDNA, including caveolae- and clathrin-mediated endocytosis, macropinocytosis, and the clathrin-independent carrier/glycosylphosphatidylinositol-anchored protein-enriched early endosomal compartment (CLIC/GEEC) pathway. Among them, macropinocytosis is the most common pathway utilized by cells having various pDNA uptake capacities, and the CLIC/GEEC pathway is observed primarily in human umbilical vein endothelial cells. Quantitatively, the endocytic pathways are more active in easy-to-transfect cells than in hard-to-transfect ones. Taken together, our data provide ultrastructural evidence showing that endocytosis plays an important role in cellular uptake and intracellular transport of electrotransfected pDNA.

Current Progress in Electrotransfection as a Nonviral Method for Gene Delivery

Electrotransfection (ET) is a nonviral method for delivery of various types of molecules into cells both in vitro and in vivo. Close to 90 clinical trials that involve the use of ET have been performed, and approximately half of them are related to cancer treatment. Particularly, ET is an attractive technique for cancer immunogene therapy because treatment of cells with electric pulses alone can induce immune responses to solid tumors, and the responses can be further enhanced by ET of plasmid DNA (pDNA) encoding therapeutic genes. Compared to other gene delivery methods, ET has several unique advantages. It is relatively inexpensive, flexible, and safe in clinical applications, and introduces only naked pDNA into cells without the use of additional chemicals or viruses. However, the efficiency of ET is still low, partly because biological mechanisms of ET in cells remain elusive. In previous studies, it was believed that pDNA entered the cells through transient pores created by electric pulses. As a result, the technique is commonly referred to as electroporation. However, recent discoveries have suggested that endocytosis plays an important role in cellular uptake and intracellular transport of electrotransfected pDNA. This review will discuss current progresses in the study of biological mechanisms underlying ET and future directions of research in this area. Understanding the mechanisms of pDNA transport in cells is critical for the development of new strategies for improving the efficiency of gene delivery in tumors.

NDV entry into dendritic cells through macropinocytosis and suppression of T lymphocyte proliferation

Newcastle disease virus (NDV) causes major economic losses in the poultry industry. Previous studies have shown that NDV utilizes different pathways to infect various cells, including dendritic cells (DCs). Here, we demonstrate that NDV gains entry into DCs mainly via macropinocytosis and clathrin-mediated endocytosis. The detection of cytokines interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-12 (IL-12), interleukin-4 (IL-4) and interleukin-10 (IL-10) indicates that NDV significantly induces Th1 responses and lowers Th2 responses. Furthermore, NDV entry into DCs resulted in the upregulation of TNF-related apoptosis-inducing ligand (TRAIL) and cleaved caspase-3 proteins, which in turn activated the extrinsic apoptosis pathway and induced DCs apoptosis. Transwell® co-culture demonstrated that direct contact between live NDV-stimulated DCs and T cells, rather than heated-inactivated NDV, inhibited CD4⁺ T cell proliferation. Taken together, these findings provide new insights into the mechanism underlying NDV infections, particularly in relation to antigen presentation cells and suppression of T cell proliferation.

Calcium-MicroRNA Complex-Functionalized Nanotubular Implant Surface for Highly Efficient Transfection and Enhanced Osteogenesis of Mesenchymal Stem Cells

Controlling mesenchymal stem cell (MSC) differentiation by RNA interference (RNAi) is a promising approach for next-generation regenerative medicine. However, efficient delivery of RNAi therapeutics is still a limiting factor. In this study, we have developed a simple, biocompatible, and highly effective delivery method of small RNA therapeutics into human MSCs (hMSCs) from an implant surface by calcium ions. First, we demonstrated that simple Ca/siRNA targeting green fluorescent protein (GFP) nanocomplexes were able to efficiently silence GFP in GFP-expressing hMSCs with adequate Ca²⁺ concentration (>5 mM). In addition, a single transfection could obtain a long-lasting silencing effect for more than 2 weeks. All three of the main endocytosis pathways (clathrin- and caveolin-mediated endocytosis and macropinocytosis) were involved in the internalization of the Ca/siRNA complexes by MSCs, and macropinocytosis plays the most dominant role. Furthermore, the Ca/siRNA complexes could be efficiently loaded onto the titanium implant surface when pretreated with anodization to create a nanotube (NT) layer. Because of the hydrophilic property of the NT surface, the Ca/siRNA was quickly loaded (less than 4 h) with high efficiency (nearly 100%), forming an even amorphous coating. The Ca/siRNA-coated NT surface showed an initial burst release of 80% of the siRNA complexes over 2 h, which is adequate to achieve robust gene silencing of attached hMSCs. To demonstrate the therapeutic potential of our Ca/siRNA coating technology, Ca/antimiR-138 complexes were loaded on to the NT surface, which strongly enhanced the osteogenic differentiation of hMSCs. In conclusion, our findings suggest that Ca²⁺ is an effective and biocompatible carrier to deliver small RNA therapeutics into hMSCs, both in solution and from functionalized surfaces, which provides a novel approach to control the MSC differentiation and tissue regeneration.

Newcastle disease virus employs macropinocytosis and Rab5a-dependent intracellular trafficking to infect DF-1 cells

Oncolytic Newcastle disease virus (NDV) reportedly employs direct fusion of the viral envelope with the plasma membrane and caveolae-dependent endocytosis to enter cells. Here, we show that macropinocytosis and clathrin-mediated endocytosis are involved in NDV entry into a galline embryonic fibroblast cell line. Upon specific inhibition of clathrin assembly, GTPase dynamin, Na⁺/H⁺ exchangers, Ras-related C3 botulinum toxin substrate 1, p21 activated kinase 1 or protein kinase C, entry of NDV and its propagation were suppressed. NDV entry into cells triggers Rac1-Pak1 signaling and elicits actin rearrangement and plasma membrane ruffling. Moreover, NDV internalization within macropinosomes and trafficking involve Rab5a-positive vesicles. This is the first report demonstrating that NDV utilizes clathrin-mediated endocytosis and macropinocytosis as alternative endocytic pathways to enter cells. These findings shed new light on the molecular mechanisms underlying NDV entry into cells, and provide potential targets for NDV-mediated therapy in cancer.

RGD-Modified Albumin Nanoconjugates for Targeted Delivery of a Porphyrin Photosensitizer

Advances in photodynamic therapy of cancer have been restrained by lack of cancer specificity and side effects to normal tissues. Molecularly targeted photodynamic therapy can achieve higher cancer specificity by combination of active cancer targeting and localized laser activation. We aimed to use albumin as a carrier to prepare targeted nanoconjugates that are selective to cancer cells and smaller than conventional nanoparticles for superior tumor penetration. IRDye 700DX (IR700), a porphyrin photosensitizer, was covalently conjugated to human serum albumin that was also linked with tumor-targeting RGD peptides. With multiple IR700 and RGD molecules in a single albumin molecule, the resultant nanoconjugates demonstrated monodispersed and uniform size distribution with a diameter of 10.9 nm. These targeted nanoconjugates showed 121-fold increase in cellular delivery of IR700 into TOV21G ovarian cancer cells compared to control nanoconjugates. Mechanistic studies revealed that the integrin specific cellular delivery was achieved through dynamin-mediated caveolae-dependent endocytosis pathways. They produced massive cell killing in TOV21G cells at low nanomolar concentrations upon light irradiation, while NIH/3T3 cells that do not express integrin αvβ3 were not affected. Because of their small size, targeted albumin nanoconjugates could penetrate tumor spheroids of SKOV-3 ovarian cancer cells and produced strong phototoxicity in this 3-D model. Owing to their cancer-specific delivery and small size, these targeted nanoconjugates may become an effective drug delivery system for enabling molecularly targeted photodynamic therapy of cancer.

Involvement of a Rac1-Dependent Macropinocytosis Pathway in Plasmid DNA Delivery by Electrotransfection

Electrotransfection is a widely used method for delivering genes into cells with electric pulses. Although different hypotheses have been proposed, the mechanism of electrotransfection remains controversial. Previous studies have indicated that uptake and intracellular trafficking of plasmid DNA (pDNA) are mediated by endocytic pathways, but it is still unclear which pathways are directly involved in the delivery. To this end, the present study investigated the dependence of electrotransfection on macropinocytosis. Data from the study demonstrated that electric pulses induced cell membrane ruffling and actin cytoskeleton remodeling. Using fluorescently labeled pDNA and a macropinocytosis marker (i.e., dextran), the study showed that electrotransfected pDNA co-localized with dextran in intracellular vesicles. Furthermore, electrotransfection efficiency could be decreased significantly by reducing temperature or treatment of cells with a pharmacological inhibitor of Rac1 and could be altered by changing Rac1 activity. Taken together, the findings suggested that electrotransfection of pDNA involved Rac1-dependent macropinocytosis.