Biomedical subjects

Paul D Robbins

Publications and source records attributed to Paul D Robbins.

At least 55 records · Page 3Linked to original sources

PubMed2003

Protection of islets by in situ peptide-mediated transduction of the Ikappa B kinase inhibitor Nemo-binding domain peptide.

We have previously demonstrated that adenoviral gene transfer of the NF-kappaB inhibitor IkappaB to human islets results in protection from interleukin (IL)-1beta-mediated dysfunction and apoptosis. Here we report that human and mouse islets can be efficiently transduced by a cationic peptide transduction domain (PTD-5) without impairment of islet function. PTD mediated delivery of a peptide inhibitor of the IL-1beta-induced IkappaB kinase (IKK), derived from IKKbeta (NBD; Nemo-binding domain), and completely blocked the detrimental effects of IL-1beta on islet function and NF-kappaB activity, in a similar manner to Ad-IkappaB. We also demonstrate that mouse islets can be transduced in situ by infusion of the transduction peptide through the bile duct prior to isolation, resulting in 40% peptide transduction of the beta-cells. Delivery of the IKK inhibitor transduction fusion peptide (PTD-5-NBD) in situ to mouse islets resulted in improved islet function and viability after isolation. These results demonstrate the feasibility of using PTD-mediated delivery to transiently modify islets in situ to improve their viability and function during isolation, prior to transplantation.

Adenoviridae↗

PubMed2003

Dendritic cells transduced to express interleukin-4 prevent diabetes in nonobese diabetic mice with advanced insulitis.

Our previous studies demonstrated that adoptive transfer of dendritic cells (DC) prevents diabetes in young nonobese diabetic (NOD) mice by inducing regulatory T(H)2 cells. In this report, as a means of treating NOD mice with more advanced insulitis, we infected DC with adenoviral vectors expressing interleukin (IL)-4 (Ad.IL-4), eGFP (Ad.eGFP), or empty vector (Ad psi 5). DC infected with any of the Ad vectors expressed higher levels of CD40, CD80, and CD86 molecules than uninfected DC and Ad.IL-4 DC produced IL-4 after lipopolysaccharide (LPS) and interferon (IFN)-gamma stimulation. Ad-infected DC efficiently stimulated allogeneic T cells, and cultures of T cells with Ad.IL-4 DC produced lower levels of IFN-gamma and marginally higher levels of IL-4. In vivo studies demonstrated that the Ad.eGFP DC trafficked to the pancreatic lymph nodes within 24 hr of intravenous administration, and could be visualized in the T cell areas of the spleen. The intrapancreatic IFN-gamma:IL-4 or IFN-gamma:IL-10 cytokine ratios were lower in 10-week-old mice treated with Ad.IL-4 DC, and these mice were significantly protected from disease. These results demonstrate, for the first time, that genetically modified DC can prevent diabetes in the context of advanced insulitis.

Adenoviridae↗

PubMed2003

Innate immunity mediated by the cytokine IL-1 homologue 4 (IL-1H4/IL-1F7) induces IL-12-dependent adaptive and profound antitumor immunity.

Recently, several novel members of the IL-1 family have been identified. The possible therapeutic utility and the underlying biologic role of these new members remain unclear. In the present study we analyzed the anti-tumor activity of human IL-1 homologue 4(IL-1H4; renamed IL-F7) by adenovirus-mediated gene transfer (AdIL-1H4) directly into murine tumors. In vitro expression analysis showed that IL-1H4 was a secretory protein. Treatment of an established MCA205 mouse fibrosarcoma by single intratumoral injection of AdIL-1H4 resulted in significant growth suppression. Furthermore, complete inhibition of tumor growth was observed following multiple injections of AdIL-1H4. The anti-tumor activity of IL-1H4 was abrogated in nude and SCID mice and in IL-12-, IFN-gamma-, or Fas ligand-deficient mice. In contrast, IL-1H4 was able to confer substantial anti-tumor effects in NKT-deficient mice. These results suggest that IL-1H4 could play an important role in the link between innate and adaptive immunity and may be useful for tumor immunotherapy.

Adenoviridae↗

PubMed2003

Advantages and limitations of particle-mediated transfection (gene gun) in cancer immuno-gene therapy using IL-10, IL-12 or B7-1 in murine tumor models.

BACKGROUND: Previous studies have shown that particle-mediated transfection (PMT; gene gun) is an efficient method of non-viral gene transfer. We have examined the advantages and limitations of PMT in cancer immuno-gene therapy using IL-10, IL-12 or B7-1, all of which have been shown to be effective in murine tumor models using retroviral vectors. METHODS: Murine cell lines (MCA205, MCA207, NIH-3T3) were treated with in vitro PMT, liposome-mediated transfection (LMT) or retroviral transfection. In vivo PMT was also examined for in vivo experiments using C57BL/6. RESULTS: Transfection efficiency and cytokine expression of PMT were similar to those of LMT, another non-viral approach, in culture when murine adherent cells were used. Tumor establishment of MCA205 was suppressed when they were transfected with the mIL-12 and/or mB7-1 gene using PMT in vitro. In a treatment of established tumor, vaccination with tumor cells transfected with an IL-12 gene suppressed tumor growth, whereas a B7-1 gene was not effective. When an IL-10 gene was used to supply a high level of expression for antitumor effects, neither in vitro nor in vivo PMT could suppress even tumor establishment. These failures appear to be caused by the characteristics of PMT which allows high, but transient, expression of transfected genes. CONCLUSIONS: Particle-mediated transfection is a useful non-viral transfection method in a system which does not require high-level gene expression for a prolonged time of period.

Analysis of Variance↗

PubMed2003

Identification of a synovial fibroblast-specific protein transduction domain for delivery of apoptotic agents to hyperplastic synovium.

Synovial hyperplasia, resulting in erosion of cartilage and bone, represents one of the major pathologies associated with rheumatoid arthritis. To develop an approach for efficient delivery of proteins or agents to synovium to induce targeted apoptosis of hyperplastic synovial tissue, we have screened an M13 peptide phage display library for synovial-specific transduction peptides. We identified a novel synovial-targeted transduction peptide, HAP-1, which is able to facilitate specific internalization of protein complexes into human and rabbit synovial cells in culture and rabbit synovial lining in vivo. HAP-1 and a non-tissue-specific cationic protein transduction domain, PTD-5, were fused to an antimicrobial peptide, (KLAK)(2), to generate two proapoptotic peptides termed DP2 and DP1, respectively. Administration of these peptides was able to induce apoptosis of rabbit and human synovial cells in culture, with DP2 inducing synovial cell-specific apoptosis. Intra-articular injection of DP1 and DP2 into arthritic rabbit joints with synovial hyperplasia induced extensive apoptosis of the hyperplastic synovium, while reducing the leukocytic infiltration and synovitis. These results suggest that proapoptotic peptides and, in particular, DP2 can be clinically useful for treatment of synovial hyperplasia, as well as inflammation. Moreover, the results demonstrate the feasibility of identifying tissue-specific transduction peptides capable of mediating efficient transduction in vivo.

Amino Acid Sequence↗

PubMed2003

Stroma formation and angiogenesis by overexpression of growth factors, cytokines, and proteolytic enzymes in human skin grafted to SCID mice.

Reorganization of skin during wound healing, inflammatory disorders, or cancer growth is the result of expression changes of multiple genes associated with tissue morphogenesis. We wanted to identify proteins involved in skin remodeling and select those that may be targeted for agonistic or antagonist therapeutic approaches in various disease processes. Full-thickness human skin was grafted to severe combined immunodeficient mice and injected intradermally with 38 different adenoviral vectors inserted with 37 different genes coding for growth factors, cytokines, proteolytic enzymes and their inhibitors, adhesion receptors, oncogenes, and tumor suppressor genes. Responses were characterized for infiltration of inflammatory cells, vascular density, matrix formation, fibroblast-like cell proliferation, and epidermal hyperplasia. Of the 17 growth factor vectors, 16 induced histological changes in human skin. Members of the VEGF and angiopoietin families induced neovascularization. PDGFs and TGF-betas stimulated connective tissue formation, and the chemokines IL-8 and MCP-1 attracted inflammatory neutrophils and monocytes, respectively. The serine protease uPA induced a vascular response similar to that of VEGF. Vectors with adhesion receptors, oncogenes and tumor suppressor genes had, with few exceptions, little effects on skin architecture. The overall results suggest that adenoviral vectors can effectively remodel the architecture of human skin for studies in morphogenesis, inflammatory skin disorders, wound healing, and cancer development.

Adenoviridae↗

PubMed2003

Differential effects of IL-12 on the generation of alloreactive CTL mediated by murine and human dendritic cells: a critical role for nitric oxide.

We examined the mechanisms involved in interleukin (IL)-12-mediated suppression of cellular immunity in mice using allogeneic mixed leukocyte reaction (MLR) stimulated by dendritic cells (DCs) in vitro and compared the effect of IL-12 on MLR in mice and humans. Although IL-12 stimulated human MLR, the addition of IL-12 or interferon-gamma (IFN-gamma) resulted in a dose-dependent suppression of MLR in mice. The treatment with N(G)-monomethyl-L-arginine (L-NMMA) completely abrogated IL-12- and IFN-gamma-mediated suppression of MLR in mice. Furthermore, IL-12 enhanced the alloreactive cytolytic T lymphocyte (CTL) induction in human MLR, whereas the addition of L-NMMA was required to generate alloreactive CTLs in the presence of IL-12 in mice. Nitric oxide (NO) was detected only in mouse MLR. Murine DCs could produce NO, but neither human CD34(+) cell- nor monocyte-derived DCs produced a detectable amount of NO. These results suggest that NO produced by DCs might play an important role in IL-12-mediated immune suppression in mice but not in humans.

Animals↗

PubMed2003

Gene transfer of manganese superoxide dismutase extends islet graft function in a mouse model of autoimmune diabetes.

Islet transplantation is a promising cure for diabetes. However, inflammation, allorejection, and recurrent autoimmune damage all may contribute to early graft loss. Pancreatic islets express lower levels of antioxidant genes than most other tissues of the body, and beta-cells in particular are sensitive to oxidative damage. Therefore, damage from oxidative stress may pose a major obstacle to islet replacement therapy in that both the islet isolation and transplantation processes generate oxygen radicals. To determine whether antioxidant gene overexpression in isolated pancreatic islets can prevent oxidative damage and prolong islet function after transplantation, we used the NOD mouse model to study oxidative stress encountered during both transplantation and autoimmune attack. We transferred an antioxidant gene, manganese superoxide dismutase (MnSOD), by adenoviral infection into isolated islets that were transplanted into streptozotocin-treated NODscid recipient mice. Functioning islet grafts were subsequently exposed to diabetogenic spleen cells and monitored until graft failure. The results show that islet grafts overexpressing MnSOD functioned approximately 50% longer than control grafts. This significant prolongation of graft function suggests that the antioxidant activity of MnSOD is beneficial to transplanted islet survival and may be used in combination with other strategies aimed at islet graft protection.

Adenoviridae↗

PubMed2003

The insulin secretory granule is the major site of K(ATP) channels of the endocrine pancreas.

With ATP sites on K(ir)6.2 that inhibit activity and ADP sites on SUR1 that antagonize the inhibition, ATP-sensitive potassium channels (K(ATP) channels) are designed as exquisite sensors of adenine nucleotide levels that signal changes in glucose metabolism. If pancreatic K(ATP) channels localize to the insulin secretory granule, they would be well positioned to transduce changes in glucose metabolism into changes in granule transport and exocytosis. Tests for pancreatic K(ATP) channels localized to insulin secretory granules led to the following observations: fluorescent sulfonylureas that bind the pancreatic K(ATP) channel specifically label intracellular punctate structures in cells of the endocrine pancreas. The fluorescent glibenclamides colocalize with Ins-C-GFP, a live-cell fluorescent reporter of insulin granules. Expression of either SUR1-GFP or K(ir)6.2-GFP fusion proteins, but not expression of GFP alone, directs GFP fluorescence to insulin secretory granules. An SUR1 antibody specifically labels insulin granules identified by anti-insulin. Two different K(ir)6.2 antibodies specifically label insulin secretory granules identified by anti-insulin. Immunoelectron microscopy showed K(ir)6.2 antibodies specifically label perimeter membrane regions of the secretory granule. Relatively little or no labeling of other structures, including the plasma membrane, was found. Our results demonstrate that the insulin secretory granule is the major site of K(ATP) channels of the endocrine pancreas.

ATP-Binding Cassette Transporters↗

PubMed2003

Prevention of diabetes in NOD mice by administration of dendritic cells deficient in nuclear transcription factor-kappaB activity.

Abnormalities of dendritic cells (DCs) have been identified in type 1 diabetic patients and in nonobese diabetic (NOD) mice that are associated with augmented nuclear transcription factor (NF)-kappaB activity. An imbalance that favors development of the immunogenic DCs may predispose to the disease, and restoration of the balance by administration of DCs deficient in NF-kappaB activity may prevent diabetes. DCs propagated from NOD mouse bone marrow and treated with NF-kappaB-specific oligodeoxyribonucleotide (ODN) in vitro (NF-kappaB ODN DC) were assessed for efficacy in prevention of diabetes development in vivo. Gel shift assay with DC nuclear extracts confirmed specific inhibition of NF-kappaB DNA binding by NF-kappaB ODN. The costimulatory molecule expression, interleukin (IL)-12 production, and immunostimulatory capacity in presenting allo- and islet-associated antigens by NF-kappaB ODN DC were significantly suppressed. NF-kappaB ODN renders DCs resistant to lipopolysaccharide stimulation. Administration of 2 x 10(6) NF-kappaB ODN DCs into NOD mice aged 6-7 weeks effectively prevented the onset of diabetes. T-cells from pancreatic lymph nodes of NF-kappaB ODN DC-treated animals exhibited hyporesponsiveness to islet antigens with low production of interferon-gamma and IL-2. These findings provide novel insights into the mechanisms of autoimmune diabetes and may lead to development of novel preventive strategies.

Animals↗

PubMed2002

Interleukin-17 promotes angiogenesis and tumor growth.

Interleukin-17 (IL-17) is a CD4 T-cell-derived proinflammatory cytokine. We investigated the effects of locally produced IL-17 by tumors as a means to evaluate its biologic function. Although recombinant IL-17 protein or retroviral transduction of IL-17 gene into tumors did not affect in vitro proliferation, IL-17 transfectants grew more rapidly in vivo when compared with controls. Immunostaining for Factor VIII revealed that tumors transduced with IL-17 had significantly higher vascular density when compared with controls. IL-17 indeed elicited neovascularization in rat cornea. In addition, angiogenic activity present in the conditioned media of CD4 T cells was markedly suppressed by neutralizing monoclonal antibody to IL-17. IL-17 had no direct effect on the growth of vascular endothelial cells, whereas IL-17 significantly stimulated migration. IL-17 also markedly promoted the cord formation of vascular endothelial cells. In addition, IL-17 up-regulated elaboration of a variety of proangiogenic factors by fibroblasts as well as tumor cells. These findings reveal a novel role for IL-17 as a CD4 T-cell-derived mediator of angiogenesis that stimulates vascular endothelial cell migration and cord formation and regulates production of a variety of proangiogenic factors. Furthermore, they suggest that inhibition of biologic action of IL-17 may have therapeutic benefits when applied to angiogenesis-related disorders.

Animals↗

PubMed2002

Interleukin 18 gene transfer expands the repertoire of antitumor Th1-type immunity elicited by dendritic cell-based vaccines in association with enhanced therapeutic efficacy.

Dendritic cells (DCs) are potent antigen-presenting cells that can prime and boost systemic antitumor immunity. Here, we have evaluated the ability of DCs transfected to secrete the potent Th1-biasing cytokine interleukin (IL)-18 to promote enhanced antitumor immunity in a mouse sarcoma model. DCs infected with a recombinant adenovirus encoding IL-18 (AdIL18DC) expressed higher levels of MHC and costimulatory molecules and were better stimulators than control DCs in mixed leukocyte reactions in vitro. Immunization of BALB/c mice bearing established day 7 CMS4 tumors with tumor peptide-pulsed control Adpsi5-transfected DCs or nontransduced DCs significantly inhibited the growth of established tumors but did not lead to complete regression of established tumors. Importantly, immunization with antigen-loaded AdIL18DC resulted in tumor rejection or further suppression of tumor growth when compared with controls. The repertoire of naturally presented tumor peptides recognized by splenocytes (as deduced in IFN-gamma ELISA assays) from AdIL18DC-treated animals was far more diverse and of greater magnitude than that of all other groups, in association with improved therapeutic outcome. These results support the ability of IL-18 gene transfer to enhance the capacity of DCs to drive broadly reactive Th1-type therapeutic immunity prompted by single peptide epitope-based vaccines (i.e., epitope spreading).

Adenoviridae↗

PubMed2002

Marked prolongation of cardiac allograft survival by dendritic cells genetically engineered with NF-kappa B oligodeoxyribonucleotide decoys and adenoviral vectors encoding CTLA4-Ig.

Bone marrow-derived dendritic cells (DCs) can be genetically engineered using adenoviral (Ad) vectors to express immunosuppressive molecules that promote T cell unresponsiveness. The success of these DCs for therapy of allograft rejection has been limited in part by the potential of the adenovirus to promote DC maturation and the inherent ability of the DC to undergo maturation following in vivo administration. DC maturation occurs via NF-kappaB-dependent mechanisms, which can be blocked by double-stranded "decoy" oligodeoxyribonucleotides (ODNs) containing binding sites for NF-kappaB. Herein, we describe the combined use of NF-kappaB ODNs and rAd vectors encoding CTLA4-Ig (Ad CTLA4-Ig) to generate stably immature murine myeloid DCs that secrete the potent costimulation blocking agent. These Ad CTLA4-Ig-transduced ODN DCs exhibit markedly impaired allostimulatory ability and promote apoptosis of activated T cells. Furthermore, administration of Ad CTLA4-Ig ODN-treated donor DCs (C57BL10; B10(H-2b)) before transplant significantly prolongs MHC-mismatched (C3HHeJ; C3H(H-2k)) vascularized heart allograft survival, with long-term (>100 days) donor-specific graft survival in 40% of recipients. The mechanism(s) responsible for DC tolerogenicity, which may involve activation-induced apoptosis of alloreactive T cells, do not lead to skewing of intragraft Th cytokine responses. Use of NF-kappaB antisense decoys in conjunction with rAd encoding a potent costimulation blocking agent offers promise for therapy of allograft rejection or autoimmune disease with minimization of systemic immunosuppression.

Abatacept↗

PubMed2002

Immunosuppressive effects of glucosamine.

Glucosamine is a naturally occurring derivative of glucose and is an essential component of glycoproteins and proteoglycans, important constituents of many eukaryotic proteins. In cells, glucosamine is produced enzymatically by the amidation of glucose 6-phosphate and can then be further modified by acetylation to result in N-acetylglucosamine. Commercially, glucosamine is sold over-the-counter to relieve arthritis. Although there is evidence in favor of the beneficial effects of glucosamine, the mechanism is unknown. Our data demonstrate that glucosamine suppresses the activation of T-lymphoblasts and dendritic cells in vitro as well as allogeneic mixed leukocyte reactivity in a dose-dependent manner. There was no inherent cellular toxicity involved in the inhibition, and the activity was not reproducible with other amine sugars. More importantly, glucosamine administration prolonged allogeneic cardiac allograft survival in vivo. We conclude that, despite its documented effects on insulin sensitivity, glucosamine possesses immunosuppressive activity and could be beneficial as an immunosuppressive agent.

Adenosine Triphosphate↗

PubMed2002

Efficiency of protein transduction is cell type-dependent and is enhanced by dextran sulfate.

Protein transduction domains (PTDs), both naturally occurring and synthetic, have been increasingly utilized to deliver biologically active agents to a variety of cell types in vitro and in vivo. We report that in addition to previously characterized arginine-rich PTDs, including TAT, lysine homopolymers were able to mediate transduction of a wide variety of cell types, as measured by flow cytometric and enzymatic assays. The efficiency of PTD-mediated transduction was influenced by the cell type tested, although polylysine homopolymers demonstrate levels of internalization that consistently exceeded those of TAT and arginine homopolymers. Transduction of arginine/lysine-rich PTDs occurred at 4 degrees C and following depletion of cellular ATP pools, albeit generally at reduced levels. Although transduction was reduced in Chinese hamster ovary mutant lines deficient in either heparan sulfate or glycosaminoglycan synthesis, uptake was restored to wild-type levels by incubating target cells with dextran sulfate. The enhancement of transduction by dextran sulfate suggests that electrostatic interactions play an important first step in the process by which PTDs and their cargo traverse the plasma membrane.

Animals↗

PubMed2002

Imaging secretory vesicles by fluorescent protein insertion in propeptide rather than mature secreted peptide.

We combined confocal and live-cell imaging with a novel molecular strategy aimed at revealing mechanisms underlying glucose-regulated insulin vesicle secretion. The 'Ins-C-GFP' reporter monitors secretory peptide targeting, trafficking, and exocytosis without directly tagging the mature secreted peptide. We trapped a green fluorescent protein (GFP) reporter in equimolar quantity within the secretory vesicle by fusing it within the C peptide of proinsulin which only after nascent vesicle sealing and acidification is cleaved from the mature secreted A and B chains of insulin. Ins-C-GFP expression in mouse islets without fail exhibited punctate distribution of green fluorescence by confocal microscopy. Ins-C-GFP colocalized GFP with insulin at vesicle dense cores by immuno-electron microscopy. Glucose stimulation decreased vesicle fluorescence coordinately with enhanced secretion from islets of C-GFP detected by anti-GFP Western blots, and of insulin detected by anti-insulin radioimmunoassay. An insulin secretagogue with a red fluorescent label, glibenclamide BODIPY TR, was applied to islets expressing Ins-C-GFP. The stimulus response was imaged as a rise in red secretagogue leading to marked loss in green granules. Since neuropeptides as well as peptide hormones are processed from propeptides after sealing of secretory granules, vesicle trapping likely is widely applicable for studies on targeting, trafficking, and regulated release of secretory peptides.

Animals↗

PubMed2002

Approaches for skeletal gene therapy.

The role of gene therapy in the treatment of musculoskeletal disorders continues to be an active area of research. As the etiology of many musculoskeletal diseases becomes increasingly understood, advances in cellular and gene therapy maybe applied to their potential treatment This review focuses on current investigational strategies to treat osteogenesis imperfecta (OI). OI is a varied group of genetic disorders that result in the diminished integrity of connective tissues as a result of alterations in the genes that encode for either the pro alpha1 or pro alpha2 component of type I collagen. Because most forms of OI result from dominant negative mutations, isolated gene replacement therapy is not a logical treatment option. The combined use of genetic manipulation and cellular transplantation, however, may provide a means to overcome this obstacle. This article describes the recent laboratory and clinical advances in cell therapy, highlights potential techniques being investigated to suppress the expression of the mutant allele with antisense gene therapy, and attempts to deliver collagen genes to bone cells. The challenges that the investigators face in their quest for the skeletal gene therapy are also discussed.

Animals↗

PubMed2002

Development of gene-based therapies for cartilage repair.

Articular cartilage is particularly vulnerable to injury and degenerative conditions, and has a limited capacity for self-repair. Although current clinical procedures cannot restore a normal articular surface, there are a growing number of proteins that may be used to augment a repair process, or protect cartilage from degeneration. Because proteins are often difficult to administer effectively, gene therapy approaches are being developed to provide their sustained synthesis at sites of injury or disease. To promote cartilage repair, cDNAs can be targeted to synovium, or cartilage. Gene transfer to the synovium is generally considered more suitable for chondroprotective therapies that rely on expression of large amounts of anti-inflammatory mediators. The delivery of genes to cartilage defects to promote enhanced repair can be performed by either direct administration of gene delivery vectors, or by implantation of genetically modified chondrogenic cells. Variations of these methods have been used to demonstrate that exogenous cDNAs encoding growth factors can be delivered locally to sites of cartilage damage where they are expressed at physiologically relevant levels. Data is beginning to emerge that suggests that delivery and expression of these genescan influence a repair response toward the synthesis of normal articular cartilage in vivo. This article reviews the current status of gene delivery for cartilage healing and presents some of the remaining challenges.

Animals↗