We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene the... more We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene therapy which 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 (TEM), 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.
An ultrasensitive method for detecting protein analytes has been developed. The system relies on ... more An ultrasensitive method for detecting protein analytes has been developed. The system relies on magnetic microparticle probes with antibodies that specifically bind a target of interest [prostate-specific antigen (PSA) in this case] and nanoparticle probes that are encoded with DNA that is unique to the protein target of interest and antibodies that can sandwich the target captured by the microparticle probes. Magnetic separation of the complexed probes and target followed by dehybridization of the oligonucleotides on the nanoparticle probe surface allows the determination of the presence of the target protein by identifying the oligonucleotide sequence released from the nanoparticle probe. Because the nanoparticle probe carries with it a large number of oligonucleotides per protein binding event, there is substantial amplification and PSA can be detected at 30 attomolar concentration. Alternatively, a polymerase chain reaction on the oligonucleotide bar codes can boost the sensiti...
(2004). Nanostructures in biodefense and molecular diagnostics. Expert Review of Molecular Diagno... more (2004). Nanostructures in biodefense and molecular diagnostics. Expert Review of Molecular Diagnostics: Vol. 4, No. 6, pp. 749-751.
Objectives Patients with rheumatoid arthritis (RA) have a reduced life expectancy due to increase... more Objectives Patients with rheumatoid arthritis (RA) have a reduced life expectancy due to increased cardiovascular disease. The lack of a suitable animal model resembling both RA and atherosclerosis has hindered studies demonstrating a direct link between systemic infl ammation in RA and the development of atherosclerosis. Our objective was to overcome this barrier by generating an animal model (K/BxA g7) that spontaneously develops both RA-like disease and atherosclerosis. Methods Arthritis severity was evaluated using clinical indices and immunohistochemical staining of ankle joint specimens. Aortic atherosclerosis was delineated via Sudan IV staining and immunohistochemical analysis. Serum cholesterol and lipoprotein levels were measured using enzymatic assays. Serum levels of cytokines, chemokines and adipokines were determined by Luminex assays. Results K/BxA g7 mice developed a destructive arthropathy followed by prominent aortic atherosclerosis. These animals also displayed dyslipidaemia, characterised by reduced serum levels of total cholesterol and highdensity lipoprotein, and increased low-density lipoprotein (LDL)/vLDL compared with control mice. Further, there were higher levels of circulating infl ammatory mediators, such as interleukin-6, sRANKL and CCL5 in atherosclerotic K/BxA g7 mice compared with controls. Treatment with etanercept reduced arthritis and atherosclerosis development in K/BxA g7 mice. Conclusions K/BxA g7 mice recapitulate the same sequence of events occurring in patients with RA, namely an erosive, infl ammatory arthritis followed by atherosclerosis. These data suggest that the K/BxA g7 mouse is a novel system for investigating the interplay between systemic infl ammation occurring in RA and the development of atherosclerosis.
Trinucleotide repeat (TNR) expansions in the genome cause a number of degenerative diseases. A pr... more 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 deathin 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-base...
Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It ... more 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.
Despite the tremendous stage migration associated with prostate cancer screening to our knowledge... more Despite the tremendous stage migration associated with prostate cancer screening to our knowledge it remains unproven whether prostate specific antigen based screening decreases prostate cancer specific mortality. Recent studies have shown that prostate specific antigen velocity more than 2 ng/ml per year in the year before diagnosis is associated with a significantly greater risk of prostate cancer specific mortality after treatment. This may serve as a surrogate marker for prostate cancer outcomes. We compared the prostate specific antigen velocity profile between patients with prostate cancer in whom the tumor was detected in a formal screening study and those who were referred for treatment. We evaluated prostate specific antigen velocity in 1,101 men from a prostate cancer screening study and in 368 not enrolled in a screening study who were referred for treatment. All patients underwent radical prostatectomy for clinically localized disease and had multiple preoperative prostate specific antigen measurements to calculate prostate specific antigen velocity. Median prostate specific antigen velocity before diagnosis was significantly higher in referred vs screened men (1.35 vs 0.68 ng/ml per year, p <0.0001). In addition, a significantly greater proportion of referred patients had prostate specific antigen velocity more than 2 ng/ml per year (38% vs 17%, p <0.0001). On multivariate analysis using prostate specific antigen, clinical stage and biopsy Gleason score screened vs referred status was a significant independent predictor of prostate specific antigen velocity more than 2 ng/ml per year (p <0.0004). Prostate specific antigen velocity more than 2 ng/ml per year has been linked to a significantly greater risk of prostate cancer specific mortality. Patients who underwent serial screening had a more favorable prostate specific antigen velocity profile at diagnosis, suggesting that screen detected prostate cancer may be more likely to be cured with definitive therapy.
Journal of materials chemistry. B, Materials for biology and medicine, Jan 14, 2016
High-density lipoproteins (HDL) are a class of natural nanostructures found in the blood and are ... more High-density lipoproteins (HDL) are a class of natural nanostructures found in the blood and are composed of lipids, proteins, and nucleic acids (e.g. microRNA). Their size, which appears to be well-suited for both tissue penetration/retention as well as payload delivery, long circulation half-life, avoidance of endosomal sequestration, and potential low toxicity are all excellent properties to model in a drug delivery vehicle. In this review, we consider high-density lipoproteins for therapeutic delivery systems. First we discuss the structure and function of natural HDL, describing in detail its biogenesis and transformation from immature, discoidal forms, to more mature, spherical forms. Next we consider features of HDL making them suitable vehicles for drug delivery. We then describe the use of natural HDL, discoidal HDL analogs, and spherical HDL analogs to deliver various classes of drugs, including small molecules, lipids, and oligonucleotides. We briefly consider the notion ...
Prior studies have reported that men with a PSA density (PSAD) less than 0.15, less than 3 positi... more Prior studies have reported that men with a PSA density (PSAD) less than 0.15, less than 3 positive biopsy cores, 50% or less of any core involved, and a Gleason score 6 or lower are likely to have "insignificant" prostate cancer (CaP) in their radical prostatectomy (RRP) specimen. In this study, we examined the ability of PSAD and biopsy features to predict pathologic outcomes in a contemporary RRP population. From 1999 to 2005, 274 men underwent RRP and had the required data for our analysis. As our database does not record the percentage or length of cancer in each biopsy core, we examined the relative importance of PSAD, the number of positive biopsy cores, and Gleason grade to predict "insignificant" cancer, defined as organ-confined with a tumor volume less than 0.5 mL and no Gleason pattern 4 or 5. Overall, by these criteria, 24.5% of patients were considered to have potentially "insignificant" cancer preoperatively; whereas, only 2.6% had a so-c...
Langmuir : the ACS journal of surfaces and colloids, Jan 17, 2015
Maintaining the intrinsic features of mesophases is critically important when employing phospholi... more Maintaining the intrinsic features of mesophases is critically important when employing phospholipid self-assemblies to mimic biomembranes. Inorganic solid surfaces provide platforms to support, guide, and analyze organic self-assemblies but impose upon them a tendency to form well-ordered phases not often found in biomembranes. To address this, we measured mesophase formation in a thiolate self-assembled monolayer (SAM) of diacyl phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) on Au(111), and provide thermodynamic analysis on the mixing behavior of inequivalent DPPTE acyl chains. Our work has uncovered three fundamental issues that enable mesophase formation: (1) Elimination of templating effects of the solid surface, (2) Weakening intermolecular and molecule-substrate interactions in adsorbates, and (3) Equilibrium through entropy-driven self-assembly. Thus, our work provides a more holistic understanding of phase behavior, from liquid phases to mesophases to...
Robust passive and active effl ux of cellular cholesterol to a designer functional mimic of high ... more Robust passive and active effl ux of cellular cholesterol to a designer functional mimic of high density lipoprotein. J.
The efficiency of islet graft survival after intraportal implantation is compromised by host inna... more 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 β-cell survival and function. We hypothesized that small interfering RNA targeting of IKKβ, 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. To test this hypothesis, we prepared small interfering RNA-based spherical nucleic acid nanoparticle conjugates targeting IKKβ IKKβ SNA-NCs). We treated isolated islets with IKKβ SNA-NCs and assessed the functional consequences of IKKβ knockdown in vitro and after intraportal transplantation in mice. Treatment of freshly isolated mouse islets with IKKβ SNA-NCs reduced constitutive IKKβ expression and protected against proinflammatory cytokine-induced NF-κB activation, resulting in improved cell viability and decreased expression of gene products associated with β-cell dysfunction. Intraportal transplantation of a marginal mass (50 islets) of syngeneic islets treated with nanoparticle conjugates targeting IKKβ 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. 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 IKKβ SNA-NCs may be a promising therapy to enhance islet graft function and survival after transplantation.
Background-Transplantation of pancreatic islets is an effective treatment for select patients wit... more 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 non-viral 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 (i.e. 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.
We report a novel entity of plasma cell bladder infiltration without other demonstrable disease. ... more We report a novel entity of plasma cell bladder infiltration without other demonstrable disease. The patient had severe irritative voiding symptoms, hematuria, and a diffuse mucosal infiltrate with 90% plasma cells. Although the patient demonstrated some clinical and pathologic evidence consistent with interstitial cystitis and eosinophilic cystitis, a predominant finding of focal plasma cell infiltration of the urinary bladder suggests a new or previously unrecognized clinical entity. UROLOGY 64: 156.e1-156.e2, 2004.
We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene the... more We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene therapy which 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 (TEM), 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.
An ultrasensitive method for detecting protein analytes has been developed. The system relies on ... more An ultrasensitive method for detecting protein analytes has been developed. The system relies on magnetic microparticle probes with antibodies that specifically bind a target of interest [prostate-specific antigen (PSA) in this case] and nanoparticle probes that are encoded with DNA that is unique to the protein target of interest and antibodies that can sandwich the target captured by the microparticle probes. Magnetic separation of the complexed probes and target followed by dehybridization of the oligonucleotides on the nanoparticle probe surface allows the determination of the presence of the target protein by identifying the oligonucleotide sequence released from the nanoparticle probe. Because the nanoparticle probe carries with it a large number of oligonucleotides per protein binding event, there is substantial amplification and PSA can be detected at 30 attomolar concentration. Alternatively, a polymerase chain reaction on the oligonucleotide bar codes can boost the sensiti...
(2004). Nanostructures in biodefense and molecular diagnostics. Expert Review of Molecular Diagno... more (2004). Nanostructures in biodefense and molecular diagnostics. Expert Review of Molecular Diagnostics: Vol. 4, No. 6, pp. 749-751.
Objectives Patients with rheumatoid arthritis (RA) have a reduced life expectancy due to increase... more Objectives Patients with rheumatoid arthritis (RA) have a reduced life expectancy due to increased cardiovascular disease. The lack of a suitable animal model resembling both RA and atherosclerosis has hindered studies demonstrating a direct link between systemic infl ammation in RA and the development of atherosclerosis. Our objective was to overcome this barrier by generating an animal model (K/BxA g7) that spontaneously develops both RA-like disease and atherosclerosis. Methods Arthritis severity was evaluated using clinical indices and immunohistochemical staining of ankle joint specimens. Aortic atherosclerosis was delineated via Sudan IV staining and immunohistochemical analysis. Serum cholesterol and lipoprotein levels were measured using enzymatic assays. Serum levels of cytokines, chemokines and adipokines were determined by Luminex assays. Results K/BxA g7 mice developed a destructive arthropathy followed by prominent aortic atherosclerosis. These animals also displayed dyslipidaemia, characterised by reduced serum levels of total cholesterol and highdensity lipoprotein, and increased low-density lipoprotein (LDL)/vLDL compared with control mice. Further, there were higher levels of circulating infl ammatory mediators, such as interleukin-6, sRANKL and CCL5 in atherosclerotic K/BxA g7 mice compared with controls. Treatment with etanercept reduced arthritis and atherosclerosis development in K/BxA g7 mice. Conclusions K/BxA g7 mice recapitulate the same sequence of events occurring in patients with RA, namely an erosive, infl ammatory arthritis followed by atherosclerosis. These data suggest that the K/BxA g7 mouse is a novel system for investigating the interplay between systemic infl ammation occurring in RA and the development of atherosclerosis.
Trinucleotide repeat (TNR) expansions in the genome cause a number of degenerative diseases. A pr... more 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 deathin 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-base...
Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It ... more 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.
Despite the tremendous stage migration associated with prostate cancer screening to our knowledge... more Despite the tremendous stage migration associated with prostate cancer screening to our knowledge it remains unproven whether prostate specific antigen based screening decreases prostate cancer specific mortality. Recent studies have shown that prostate specific antigen velocity more than 2 ng/ml per year in the year before diagnosis is associated with a significantly greater risk of prostate cancer specific mortality after treatment. This may serve as a surrogate marker for prostate cancer outcomes. We compared the prostate specific antigen velocity profile between patients with prostate cancer in whom the tumor was detected in a formal screening study and those who were referred for treatment. We evaluated prostate specific antigen velocity in 1,101 men from a prostate cancer screening study and in 368 not enrolled in a screening study who were referred for treatment. All patients underwent radical prostatectomy for clinically localized disease and had multiple preoperative prostate specific antigen measurements to calculate prostate specific antigen velocity. Median prostate specific antigen velocity before diagnosis was significantly higher in referred vs screened men (1.35 vs 0.68 ng/ml per year, p <0.0001). In addition, a significantly greater proportion of referred patients had prostate specific antigen velocity more than 2 ng/ml per year (38% vs 17%, p <0.0001). On multivariate analysis using prostate specific antigen, clinical stage and biopsy Gleason score screened vs referred status was a significant independent predictor of prostate specific antigen velocity more than 2 ng/ml per year (p <0.0004). Prostate specific antigen velocity more than 2 ng/ml per year has been linked to a significantly greater risk of prostate cancer specific mortality. Patients who underwent serial screening had a more favorable prostate specific antigen velocity profile at diagnosis, suggesting that screen detected prostate cancer may be more likely to be cured with definitive therapy.
Journal of materials chemistry. B, Materials for biology and medicine, Jan 14, 2016
High-density lipoproteins (HDL) are a class of natural nanostructures found in the blood and are ... more High-density lipoproteins (HDL) are a class of natural nanostructures found in the blood and are composed of lipids, proteins, and nucleic acids (e.g. microRNA). Their size, which appears to be well-suited for both tissue penetration/retention as well as payload delivery, long circulation half-life, avoidance of endosomal sequestration, and potential low toxicity are all excellent properties to model in a drug delivery vehicle. In this review, we consider high-density lipoproteins for therapeutic delivery systems. First we discuss the structure and function of natural HDL, describing in detail its biogenesis and transformation from immature, discoidal forms, to more mature, spherical forms. Next we consider features of HDL making them suitable vehicles for drug delivery. We then describe the use of natural HDL, discoidal HDL analogs, and spherical HDL analogs to deliver various classes of drugs, including small molecules, lipids, and oligonucleotides. We briefly consider the notion ...
Prior studies have reported that men with a PSA density (PSAD) less than 0.15, less than 3 positi... more Prior studies have reported that men with a PSA density (PSAD) less than 0.15, less than 3 positive biopsy cores, 50% or less of any core involved, and a Gleason score 6 or lower are likely to have "insignificant" prostate cancer (CaP) in their radical prostatectomy (RRP) specimen. In this study, we examined the ability of PSAD and biopsy features to predict pathologic outcomes in a contemporary RRP population. From 1999 to 2005, 274 men underwent RRP and had the required data for our analysis. As our database does not record the percentage or length of cancer in each biopsy core, we examined the relative importance of PSAD, the number of positive biopsy cores, and Gleason grade to predict "insignificant" cancer, defined as organ-confined with a tumor volume less than 0.5 mL and no Gleason pattern 4 or 5. Overall, by these criteria, 24.5% of patients were considered to have potentially "insignificant" cancer preoperatively; whereas, only 2.6% had a so-c...
Langmuir : the ACS journal of surfaces and colloids, Jan 17, 2015
Maintaining the intrinsic features of mesophases is critically important when employing phospholi... more Maintaining the intrinsic features of mesophases is critically important when employing phospholipid self-assemblies to mimic biomembranes. Inorganic solid surfaces provide platforms to support, guide, and analyze organic self-assemblies but impose upon them a tendency to form well-ordered phases not often found in biomembranes. To address this, we measured mesophase formation in a thiolate self-assembled monolayer (SAM) of diacyl phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) on Au(111), and provide thermodynamic analysis on the mixing behavior of inequivalent DPPTE acyl chains. Our work has uncovered three fundamental issues that enable mesophase formation: (1) Elimination of templating effects of the solid surface, (2) Weakening intermolecular and molecule-substrate interactions in adsorbates, and (3) Equilibrium through entropy-driven self-assembly. Thus, our work provides a more holistic understanding of phase behavior, from liquid phases to mesophases to...
Robust passive and active effl ux of cellular cholesterol to a designer functional mimic of high ... more Robust passive and active effl ux of cellular cholesterol to a designer functional mimic of high density lipoprotein. J.
The efficiency of islet graft survival after intraportal implantation is compromised by host inna... more 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 β-cell survival and function. We hypothesized that small interfering RNA targeting of IKKβ, 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. To test this hypothesis, we prepared small interfering RNA-based spherical nucleic acid nanoparticle conjugates targeting IKKβ IKKβ SNA-NCs). We treated isolated islets with IKKβ SNA-NCs and assessed the functional consequences of IKKβ knockdown in vitro and after intraportal transplantation in mice. Treatment of freshly isolated mouse islets with IKKβ SNA-NCs reduced constitutive IKKβ expression and protected against proinflammatory cytokine-induced NF-κB activation, resulting in improved cell viability and decreased expression of gene products associated with β-cell dysfunction. Intraportal transplantation of a marginal mass (50 islets) of syngeneic islets treated with nanoparticle conjugates targeting IKKβ 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. 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 IKKβ SNA-NCs may be a promising therapy to enhance islet graft function and survival after transplantation.
Background-Transplantation of pancreatic islets is an effective treatment for select patients wit... more 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 non-viral 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 (i.e. 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.
We report a novel entity of plasma cell bladder infiltration without other demonstrable disease. ... more We report a novel entity of plasma cell bladder infiltration without other demonstrable disease. The patient had severe irritative voiding symptoms, hematuria, and a diffuse mucosal infiltrate with 90% plasma cells. Although the patient demonstrated some clinical and pathologic evidence consistent with interstitial cystitis and eosinophilic cystitis, a predominant finding of focal plasma cell infiltration of the urinary bladder suggests a new or previously unrecognized clinical entity. UROLOGY 64: 156.e1-156.e2, 2004.
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Papers by C. Thaxton