Synthetic high-density lipoprotein nanoparticles: Good things in small packages.

Medicine has been a great beneficiary of the nanotechnology revolution. Nanotechnology involves the synthesis of functional materials with at least one size dimension between 1 and 100 nm. Advances in the field have enabled the synthesis of bio-nanoparticles that can interface with physiological systems to modulate fundamental cellular processes. One example of a diverse acting nanoparticle-based therapeutic is synthetic high-density lipoprotein (HDL) nanoparticles (NP), which have great potential for treating diseases of the ocular surface. Our group has developed a spherical HDL NP using a gold nanoparticle core. HDL NPs: (i) closely mimic the physical and chemical features of natural HDLs; (ii) contain apoA-I; (iii) bind with high-affinity to SR-B1, which is the major receptor through which HDL modulates cell cholesterol metabolism and controls the selective uptake of HDL cargo into cells; (iv) are non-toxic to cells and tissues; and (v) can be chemically engineered to display nearly any surface or core composition desired. With respect to the ocular surface, topical application of HDL NPs accelerates re-epithelization of the cornea following wounding, attenuates inflammation resulting from chemical burns and/or other stresses, and effectively delivers microRNAs with biological activity to corneal cells and tissues. HDL NPs will be the foundation of a new class of topical eye drops with great translational potential and exemplify the impact that nanoparticles can have in medicine.

Targeted reduction of cholesterol uptake in cholesterol-addicted lymphoma cells blocks turnover of oxidized lipids to cause ferroptosis.

Normal human cells can either synthesize cholesterol or take it up from lipoproteins to meet their metabolic requirements. In some malignant cells, de novo cholesterol synthesis genes are transcriptionally silent or mutated, meaning that cholesterol uptake from lipoproteins is required for survival. Recent data suggest that lymphoma cells dependent upon lipoprotein-mediated cholesterol uptake are also subject to ferroptosis, an oxygen- and iron-dependent cell death mechanism triggered by accumulation of oxidized lipids in cell membranes unless the lipid hydroperoxidase, glutathione peroxidase 4 (GPX4), reduces these toxic lipid species. To study mechanisms linking cholesterol uptake with ferroptosis and determine the potential role of the high-density lipoprotein (HDL) receptor as a target for cholesterol depleting therapy, we treated lymphoma cell lines known to be sensitive to the reduction of cholesterol uptake with HDL-like nanoparticles (HDL NPs). HDL NPs are a cholesterol-poor ligand that binds to the receptor for cholesterol-rich HDLs, scavenger receptor type B1 (SCARB1). Our data reveal that HDL NP treatment activates a compensatory metabolic response in treated cells toward increased de novo cholesterol synthesis, which is accompanied by nearly complete reduction in expression of GPX4. As a result, oxidized membrane lipids accumulate, leading to cell death through a mechanism consistent with ferroptosis. We obtained similar results in vivo after systemic administration of HDL NPs in mouse lymphoma xenografts and in primary samples obtained from patients with lymphoma. In summary, targeting SCARB1 with HDL NPs in cholesterol uptake-addicted lymphoma cells abolishes GPX4, resulting in cancer cell death by a mechanism consistent with ferroptosis.

Interparticle Molecular Exchange of Surface Chemical Components of Native High-Density Lipoproteins to Complementary Nanoparticle Scaffolds.

High-density lipoproteins (HDL) are constitutionally dynamic nanoparticles that circulate in the blood. The biological functions of HDLs are impacted by interchangeable surface chemical components, like cholesterol and HDL-associated proteins. Current methods to quantify the chemical constituents of HDL are largely restricted to clinical or academic laboratories and require expensive instrumentation, and there is no commonality to the techniques required to detect and quantify different analytes (e.g., cholesterol versus HDL-associated protein). To potentially facilitate and streamline the analysis of HDL composition, we hypothesized that mixing native HDLs with similarly sized gold nanoparticles whose surfaces are endowed with phospholipids, called complementary nanoparticle scaffolds (CNS), would enable interparticle exchange of surface components. Then, easy isolation of the newly formed particles could be accomplished using benchtop centrifugation for subsequent measurement of HDL components exchanged to the surface of the CNS. As proof-of-concept, data demonstrate that CNS incubated with only a few microliters of human serum rapidly (1 h) sequester cholesterol and HDL-associated proteins with direct correlation to native HDLs. As such, data show that the CNS assay is a single platform for rapid isolation and subsequent detection of the surface components of native HDLs.

Prostate cancer extracellular vesicles mediate intercellular communication with bone marrow cells and promote metastasis in a cholesterol-dependent manner.

Primary tumours can establish long-range communication with distant organs to transform them into fertile soil for circulating tumour cells to implant and proliferate, a process called pre-metastatic niche (PMN) formation. Tumour-derived extracellular vesicles (EV) are potent mediators of PMN formation due to their diverse complement of pro-malignant molecular cargo and their propensity to target specific cell types (Costa-Silva et al., 2015; Hoshino et al., 2015; Peinado et al., 2012; Peinado et al., 2017). While significant progress has been made to understand the mechanisms by which pro-metastatic EVs create tumour-favouring microenvironments at pre-metastatic organ sites, comparatively little attention has been paid to the factors intrinsic to recipient cells that may modify the extent to which pro-metastatic EV signalling is received and transduced. Here, we investigated the role of recipient cell cholesterol homeostasis in prostate cancer (PCa) EV-mediated signalling and metastasis. Using a bone metastatic model of enzalutamide-resistant PCa, we first characterized an axis of EV-mediated communication between PCa cells and bone marrow that is marked by in vitro and in vivo PCa EV uptake by bone marrow myeloid cells, activation of NF-κB signalling, enhanced osteoclast differentiation, and reduced myeloid thrombospondin-1 expression. We then employed a targeted, biomimetic approach to reduce myeloid cell cholesterol in vitro and in vivo prior to conditioning with PCa EVs. Reducing myeloid cell cholesterol prevented the uptake of PCa EVs by recipient myeloid cells, abolished NF-κB activity and osteoclast differentiation, stabilized thrombospondin-1 expression, and reduced metastatic burden by 77%. These results demonstrate that cholesterol homeostasis in bone marrow myeloid cells regulates pro-metastatic EV signalling and metastasis by acting as a gatekeeper for EV signal transduction.

HDL nanoparticles have wound healing and anti-inflammatory properties and can topically deliver miRNAs.

microRNAs regulate numerous biological processes, making them potential therapeutic agents. Problems with delivery and stability of these molecules have limited their usefulness as treatments. We demonstrate that synthetic high-density lipoprotein nanoparticles (HDL NPs) topically applied to the intact ocular surface are taken up by epithelial and stromal cells. microRNAs complexed to HDL NPs (miR-HDL NPs) are similarly taken up by cells and tissues and retain biological activity. Topical treatment of diabetic mice with either HDL NPs or miR-HDL NPs significantly improved corneal re-epithelialization following wounding compared with controls. Mouse corneas with alkali burn-induced inflammation, topically treated with HDL NPs, displayed clinical, morphological and immunological improvement. These results should yield a novel HDL NP-based eye drop for patients with compromised wound healing ability (diabetics) and/or corneal inflammatory diseases (e.g. dry eye).

Small interfering RNAs based on huntingtin trinucleotide repeats are highly toxic to cancer cells.

Trinucleotide repeat (TNR) expansions in the genome cause a number of degenerative diseases. A prominent TNR expansion involves the triplet CAG in the huntingtin (HTT) gene responsible for Huntington's disease (HD). Pathology is caused by protein and RNA generated from the TNR regions including small siRNA-sized repeat fragments. An inverse correlation between the length of the repeats in HTT and cancer incidence has been reported for HD patients. We now show that siRNAs based on the CAG TNR are toxic to cancer cells by targeting genes that contain long reverse complementary TNRs in their open reading frames. Of the 60 siRNAs based on the different TNRs, the six members in the CAG/CUG family of related TNRs are the most toxic to both human and mouse cancer cells. siCAG/CUG TNR-based siRNAs induce cell death in vitro in all tested cancer cell lines and slow down tumor growth in a preclinical mouse model of ovarian cancer with no signs of toxicity to the mice. We propose to explore TNR-based siRNAs as a novel form of anticancer reagents.

Induction of DISE in ovarian cancer cells in vivo.

The death receptor CD95/Fas can be activated by immune cells to kill cancer cells. shRNAs and siRNAs derived from CD95 or CD95 ligand (CD95L) are highly toxic to most cancer cells. We recently found that these sh/siRNAs kill cancer cells in the absence of the target by targeting the 3'UTRs of critical survival genes through canonical RNAi. We have named this unique form of off-target effect DISE (for death induced by survival gene elimination). DISE preferentially kills transformed cells and cancer stem cells. We demonstrate that DISE induction occurs in cancer cells in vivo after introducing a lentiviral CD95L derived shRNA (shL3) into HeyA8 ovarian cancer cells grown as i.p. xenografts in mice, when compared to a scrambled shRNA. To demonstrate the possibility of therapeutically inducing DISE, we coupled siRNAs to templated lipoprotein nanoparticles (TLP). In vitro, TLPs loaded with a CD95L derived siRNA (siL3) selectively silenced a biosensor comprised of Venus and CD95L ORF and killed ovarian cancer cells. In vivo, two siRNA-TLPs (siL2-TLP and siL3-TLP) reduced tumor growth similarly as observed for cells expressing the shL3 vector. These data suggest that it is possible to kill ovarian cancer cells in vivo via DISE induction using siRNA-TLPs.

Rational Targeting of Cellular Cholesterol in Diffuse Large B-Cell Lymphoma (DLBCL) Enabled by Functional Lipoprotein Nanoparticles: A Therapeutic Strategy Dependent on Cell of Origin.

Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It is important to identify novel, rational treatments based on biology, and cellular cholesterol metabolism as a potential target for cancer is an innovative approach. Toward this end, we focused on diffuse large B-cell lymphoma (DLBCL) as a model because there is differential cholesterol biosynthesis driven by B-cell receptor (BCR) signaling in germinal center (GC) versus activated B-cell (ABC) DLBCL. To specifically target cellular cholesterol homeostasis, we employed high-density lipoprotein-like nanoparticles (HDL NP) that can generally reduce cellular cholesterol by targeting and blocking cholesterol uptake through the high-affinity HDL receptor, scavenger receptor type B-1 (SCARB1). As we previously reported, GC DLBCL are exquisitely sensitive to HDL NP as monotherapy, while ABC DLBCL are less sensitive. Herein, we report that enhanced BCR signaling and resultant de novo cholesterol synthesis in ABC DLBCL drastically reduces the ability of HDL NPs to reduce cellular cholesterol and induce cell death. Therefore, we combined HDL NP with the BCR signaling inhibitor ibrutinib and the SYK inhibitor R406. By targeting both cellular cholesterol uptake and BCR-associated de novo cholesterol synthesis, we achieved cellular cholesterol reduction and induced apoptosis in otherwise resistant ABC DLBCL cell lines. These results in lymphoma demonstrate that reduction of cellular cholesterol is a powerful mechanism to induce apoptosis. Cells rich in cholesterol require HDL NP therapy to reduce uptake and molecularly targeted agents that inhibit upstream pathways that stimulate de novo cholesterol synthesis, thus, providing a new paradigm for rationally targeting cholesterol metabolism as therapy for cancer.

Synthetic high-density lipoproteins as targeted monotherapy for chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) remains incurable despite the introduction of new drugs. Therapies targeting receptors and pathways active specifically in malignant B cells might provide better treatment options. For instance, in B cell lymphoma, our group has previously shown that scavenger receptor type B-1 (SR-B1), the high-affinity receptor for cholesterol-rich high-density lipoproteins (HDL), is a therapeutic target. As evidence suggests that targeting cholesterol metabolism in CLL cells may have therapeutic benefit, we examined SR-B1 expression in primary CLL cells from patients. Unlike normal B cells that do not express SR-B1, CLL cells express the receptor. As a result, we evaluated cholesterol-poor synthetic HDL nanoparticles (HDL NP), known for targeting SR-B1, as a therapy for CLL. HDL NPs potently and selectively induce apoptotic cell death in primary CLL cells. HDL NPs had no effect on normal peripheral blood mononuclear cells from healthy individuals or patients with CLL. These data implicate SR-B1 as a target in CLL and HDL NPs as targeted monotherapy for CLL.

Pathways for Modulating Exosome Lipids Identified By High-Density Lipoprotein-Like Nanoparticle Binding to Scavenger Receptor Type B-1.

Exosomes are produced by cells to mediate intercellular communication, and have been shown to perpetuate diseases, including cancer. New tools are needed to understand exosome biology, detect exosomes from specific cell types in complex biological media, and to modify exosomes. Our data demonstrate a cellular pathway whereby membrane-bound scavenger receptor type B-1 (SR-B1) in parent cells becomes incorporated into exosomes. We tailored synthetic HDL-like nanoparticles (HDL NP), high-affinity ligands for SR-B1, to carry a fluorescently labeled phospholipid. Data show SR-B1-dependent transfer of the fluorescent phospholipid from HDL NPs to exosomes. Modified exosomes are stable in serum and can be directly detected using flow cytometry. As proof-of-concept, human serum exosomes were found to express SR-B1, and HDL NPs can be used to label and isolate them. Ultimately, we discovered a natural cellular pathway and nanoparticle-receptor pair that enables exosome modulation, detection, and isolation.

Properties of Native High-Density Lipoproteins Inspire Synthesis of Actively Targeted In Vivo siRNA Delivery Vehicles.

Efficient systemic administration of therapeutic short interfering RNA (siRNA) is challenging. High-density lipoproteins (HDL) are natural in vivo RNA delivery vehicles. Specifically, native HDLs: 1) Load single-stranded RNA; 2) Are anionic, which requires charge reconciliation between the RNA and HDL, and 3) Actively target scavenger receptor type B-1 (SR-B1) to deliver RNA. Emphasizing these particular parameters, we employed templated lipoprotein particles (TLP), mimics of spherical HDLs, and self-assembled them with single-stranded complements of, presumably, any highly unmodified siRNA duplex pair after formulation with a cationic lipid. Resulting siRNA templated lipoprotein particles (siRNA-TLP) are anionic and tunable with regard to RNA assembly and function. Data demonstrate that the siRNA-TLPs actively target SR-B1 to potently reduce androgen receptor (AR) and enhancer of zeste homolog 2 (EZH2) proteins in multiple cancer cell lines. Systemic administration of siRNA-TLPs demonstrated no off-target toxicity and significantly reduced the growth of prostate cancer xenografts. Thus, native HDLs inspired the synthesis of a hybrid siRNA delivery vehicle that can modularly load single-stranded RNA complements after charge reconciliation with a cationic lipid, and that function due to active targeting of SR-B1.

Mosaic Interdigitated Structure in Nanoparticle-Templated Phospholipid Bilayer Supports Partial Lipidation of Apolipoprotein A-I.

Using gold nanoparticle-templated high-density lipoprotein-like particles as a model, the nanoparticle-templated phospholipid bilayer is studied from the bottom-up. Data support the phospholipids have a mosaic interdigitated structure. The discontinuous lipid milieu supports partial lipidation of apolipoprotein A-I, different from an ordinary phospholipid bilayer, suggesting that synergy between nanoparticle templates and bound phospholipid layers can modulate amphiphilic proteins for desired functions.

Synthetic high-density lipoprotein-like nanoparticles as cancer therapy.

High-density lipoproteins (HDL) are diverse natural nanoparticles that carry cholesterol and are best known for the role that they play in cardiovascular disease. However, due to their unique targeting capabilities, diverse molecular cargo, and natural functions beyond cholesterol transport, it is becoming increasingly appreciated that HDLs are critical to cancer development and progression. Accordingly, this chapter highlights ongoing research focused on the connections between HDL and cancer in order to design new drugs and targeted drug delivery vehicles. Research is focused on synthesizing biomimetic HDL-like nanoparticles (NP) that can be loaded with diverse therapeutic cargo (e.g., chemotherapies, nucleic acids, proteins) and specifically targeted to cancer cells. Beyond drug delivery, new data is emerging that HDL-like NPs may be therapeutically active in certain tumor types, for example, B cell lymphoma. Overall, HDL-like NPs are becoming increasingly appreciated as targeted, biocompatible, and efficient therapies for cancer, and may soon become indispensable agents in the cancer therapeutic armamentarium.

Robust passive and active efflux of cellular cholesterol to a designer functional mimic of high density lipoprotein.

The ability of HDL to support macrophage cholesterol efflux is an integral part of its atheroprotective action. Augmenting this ability, especially when HDL cholesterol efflux capacity from macrophages is poor, represents a promising therapeutic strategy. One approach to enhancing macrophage cholesterol efflux is infusing blood with HDL mimics. Previously, we reported the synthesis of a functional mimic of HDL (fmHDL) that consists of a gold nanoparticle template, a phospholipid bilayer, and apo A-I. In this work, we characterize the ability of fmHDL to support the well-established pathways of cellular cholesterol efflux from model cell lines and primary macrophages. fmHDL received cell cholesterol by unmediated (aqueous) and ABCG1- and scavenger receptor class B type I (SR-BI)-mediated diffusion. Furthermore, the fmHDL holoparticle accepted cholesterol and phospholipid by the ABCA1 pathway. These results demonstrate that fmHDL supports all the cholesterol efflux pathways available to native HDL and thus, represents a promising infusible therapeutic for enhancing macrophage cholesterol efflux. fmHDL accepts cholesterol from cells by all known pathways of cholesterol efflux: unmediated, ABCG1- and SR-BI-mediated diffusion, and through ABCA1.

NanoFlares for the detection, isolation, and culture of live tumor cells from human blood.

Metastasis portends a poor prognosis for cancer patients. Primary tumor cells disseminate through the bloodstream before the appearance of detectable metastatic lesions. The analysis of cancer cells in blood­so-called circulating tumor cells (CTCs)­may provide unprecedented opportunities for metastatic risk assessment and investigation. NanoFlares are nanoconstructs that enable live-cell detection of intracellular mRNA. NanoFlares, when coupled with flow cytometry, can be used to fluorescently detect genetic markers of CTCs in the context of whole blood. They allow one to detect as few as 100 live cancer cells per mL of blood and subsequently culture those cells. This technique can also be used to detect CTCs in a murine model of metastatic breast cancer. As such, NanoFlares provide, to our knowledge, the first genetic-based approach for detecting, isolating, and characterizing live cancer cells from blood and may provide new opportunities for cancer diagnosis, prognosis, and personalized therapy.

High Density Lipoprotein Nanoparticles Deliver RNAi to Endothelial Cells to Inhibit Angiogenesis.

Systemic delivery of therapeutic nucleic acids to target cells and tissues outside of the liver remains a major challenge. We synthesized a biomimetic high density lipoprotein nanoparticle (HDL NP) for delivery of a cholesteryl modified therapeutic nucleic acid (RNAi) to vascular endothelial cells, a cell type naturally targeted by HDL. HDL NPs adsorb cholesteryl modified oligonucleotides and protect them from nuclease degradation. As proof of principle, we delivered RNAi targeting vascular endothelial growth factor receptor 2 (VEGFR2) to endothelial cells to effectively silence target mRNA and protein expression in vitro. In addition, data show that treatment strongly attenuated in vivo neovascularization measured using a standard angiogenesis assay and in hypervascular tumor allografts where a striking reduction in tumor growth was observed. For effective delivery, HDL NPs required the expression of the cell surface protein scavenger receptor type-B1 (SR-B1). No toxicity of HDL NPs was measured in vitro or after in vivo administration. Thus, by using a biomimetic approach to nucleic acid delivery, data demonstrate that systemically administered RNAi-HDL NPs target SR-B1 expressing endothelial cells to deliver functional anti-angiogenic RNAi as a potential treatment of cancer and other neo-vascular diseases.

Knockdown of intraislet IKKß by spherical nucleic acid conjugates prevents cytokine-induced injury and enhances graft survival.

BACKGROUND: The efficiency of islet graft survival after intraportal implantation is compromised by host innate immune responses and the production of proinflammatory cytokines that cause acute cellular injury. This reaction activates intraislet nuclear factor-κB (NF-κB), causing production of gene products that have detrimental effects on ß-cell survival and function. We hypothesized that small interfering RNA targeting of IKKß, a crucial kinase in the NF-κB activation pathway, in islets before transplantation would ameliorate the detrimental effects of cytokines and improve islet survival after transplantation. METHODS: To test this hypothesis, we prepared small interfering RNA-based spherical nucleic acid nanoparticle conjugates targeting IKKß IKKß SNA-NCs). We treated isolated islets with IKKß SNA-NCs and assessed the functional consequences of IKKß knockdown in vitro and after intraportal transplantation in mice. RESULTS: Treatment of freshly isolated mouse islets with IKKß SNA-NCs reduced constitutive IKKß expression and protected against proinflammatory cytokine-induced NF-κB activation, resulting in improved cell viability and decreased expression of gene products associated with ß-cell dysfunction. Intraportal transplantation of a marginal mass (50 islets) of syngeneic islets treated with nanoparticle conjugates targeting IKKß resulted in reversion to normoglycemia in 50% of streptozotocin-induced diabetic recipients (n=12) compared with 0% of controls (n=12). Histologic analyses showed reduced CD11b(+) cellular infiltration and decreased islet apoptosis. CONCLUSIONS: These results are consistent with the hypothesis that inhibition of intraislet NF-κB activation ameliorates the detrimental effects of host cytokines and demonstrates that preconditioning freshly isolated islets in culture with IKKß SNA-NCs may be a promising therapy to enhance islet graft function and survival after transplantation.

Templated high density lipoprotein nanoparticles as potential therapies and for molecular delivery.

High density lipoproteins (HDLs) are dynamic natural nanoparticles best known for their role in cholesterol transport and the inverse correlation that exists between blood HDL levels and the risk of developing coronary heart disease. In addition, enhanced HDL-cholesterol uptake has been demonstrated in several human cancers. As such, the use of HDL as a therapeutic and as a vehicle for systemic delivery of drugs and as imaging agents is increasingly important. HDLs exist on a continuum from the secreted HDL-scaffolding protein, apolipoprotein A-1 (Apo A1), to complex, spherical "mature" HDLs. Aspects of HDL particles including their size, shape, and surface chemical composition are being recognized as critical to their diverse biological functions. Here we review HDL biology; strategies for synthesizing HDLs; data supporting the clinical use and benefit of directly administered HDL; a rationale for developing synthetic methods for spherical, mature HDLs; and, the potential to employ HDLs as therapies, imaging agents, and drug delivery vehicles. Importantly, methods that utilize nanoparticle templates to control synthetic HDL size, shape, and surface chemistry are highlighted.

Biomimetic high density lipoprotein nanoparticles for nucleic acid delivery.

We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene therapy that combines lipid-based nucleic acid transfection strategies with HDL biomimicry. For proof-of-concept, HDL AuNPs are shown to adsorb antisense cholesterylated DNA. The conjugates are internalized by human cells, can be tracked within cells using transmission electron microscopy, and regulate target gene expression. Overall, the ability to directly image the AuNP core within cells, the chemical tailorability of the HDL AuNP platform, and the potential for cell-specific targeting afforded by HDL biomimicry make this platform appealing for nucleic acid delivery.

Transfection of pancreatic islets using polyvalent DNA-functionalized gold nanoparticles.

BACKGROUND: Transplantation of pancreatic islets is an effective treatment for select patients with type 1 diabetes. Improved cellular therapy results may be realized by altering the gene expression profile of transplanted islets. Current viral and nonviral vectors used to introduce nucleic acids for gene regulation hold promise, but safety and efficacy shortcomings motivate the development of new transfection strategies. Polyvalent gold nanoparticles (AuNPs) densely functionalized with covalently immobilized DNA oligonucleotides (AuNP-DNA) are new single entity transfection and gene regulating agents (ie, not requiring lipids, polymers, or viral vectors for cell entry) able to enter cells with high efficiency and no evidence of toxicity. We hypothesize that AuNP-DNA conjugates can efficiently transfect pancreatic islets with no impact on viability or functionality, and can function to regulate targeted gene expression. METHODS: AuNPs were surface-functionalized with control and antisense DNA oligonucleotides. Purified murine and human islets were exposed to AuNP-DNA conjugates for 24 hours. Islet AuNP-DNA uptake, cell viability, and functionality were measured. Furthermore, the ability of antisense AuNP-DNA conjugates to regulate gene expression was measured using murine islets expressing eGFP. RESULTS: Collectively, fluorescent confocal microscopy, transmission electron microscopy, mass spectrometry, and flow cytometry revealed substantial penetration of the AuNP-DNA conjugates into the inner core of the islets and within islet cells. No change in cellular viability occurred and the insulin stimulation index was unchanged in treated versus untreated islets. Transplantation of AuNP-DNA treated islets cured diabetic nude mice. Functionally, antisense eGFP AuNP-DNA conjugates reduced eGFP expression in MIP-eGFP islets. CONCLUSION: Polyvalent AuNP-DNA conjugates may represent the next generation of nucleic acid-based therapeutic agents for improving pancreatic islet engraftment, survival, and long-term function.