Browsing by Subject "inhibitors"

Now showing 1 - 6 of 6
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    B Cell Depletion Eliminates FVIII Memory B Cells and Enhances AAV8-coF8 Immune Tolerance Induction When Combined With Rapamycin
    (Frontiers, 2020-06) Biswas, Moanaro; Palaschak, Brett; Kumar, Sandeep R. P.; Rana, Jyoti; Markusic, David M.; Pediatrics, School of Medicine
    Hemophilia A is an inherited coagulation disorder resulting in the loss of functional clotting factor VIII (FVIII). Presently, the most effective treatment is prophylactic protein replacement therapy. However, this requires frequent life-long intravenous infusions of plasma derived or recombinant clotting factors and is not a cure. A major complication is the development of inhibitory antibodies that nullify the replacement factor. Immune tolerance induction (ITI) therapy to reverse inhibitors can last from months to years, requires daily or every other day infusions of supraphysiological levels of FVIII and is effective in only up to 70% of hemophilia A patients. Preclinical and recent clinical studies have shown that gene replacement therapy with AAV vectors can effectively cure hemophilia A patients. However, it is unclear how hemophilia patients with high risk inhibitor F8 mutations or with established inhibitors will respond to gene therapy, as these patients have been excluded from ongoing clinical trials. AAV8-coF8¬ gene transfer in naïve BALB/c-F8-/Y mice (BALB/c-HA) results in anti-FVIII IgG1 inhibitors following gene transfer, which can be prevented by transient immune modulation with anti-mCD20 (18B12) and oral rapamycin. We investigated if we could improve ITI in inhibitor positive mice by combining anti-mCD20 and rapamycin with AAV8-coF8 gene therapy. Our hypothesis was that continuous expression of FVIII protein from gene transfer compared to transient FVIII from weekly protein therapy, would enhance regulatory T cell induction and promote deletion of FVIII reactive B cells, following reconstitution. Mice that received anti-CD20 had a sharp decline in inhibitors, which corresponded to FVIII memory B (Bmem) cell deletion. Importantly, only mice receiving both anti-mCD20 and rapamycin failed to increase inhibitors following rechallenge with intravenous FVIII protein therapy. Our data show that B and T cell immune modulation complements AAV8-coF8 gene therapy in naïve and inhibitor positive hemophilia A mice and suggest that such protocols should be considered for AAV gene therapy in high risk or inhibitor positive hemophilia patients.
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    B Cell Depletion Eliminates FVIII Memory B Cells and Enhances AAV8-coF8 Immune Tolerance Induction When Combined With Rapamycin
    (Frontiers, 2020-06-24) Biswas, Moanaro; Palaschak, Brett; Kumar, Sandeep R. P.; Rana, Jyoti; Markusic, David M.; Pediatrics, School of Medicine
    Hemophilia A is an inherited coagulation disorder resulting in the loss of functional clotting factor VIII (FVIII). Presently, the most effective treatment is prophylactic protein replacement therapy. However, this requires frequent life-long intravenous infusions of plasma derived or recombinant clotting factors and is not a cure. A major complication is the development of inhibitory antibodies that nullify the replacement factor. Immune tolerance induction (ITI) therapy to reverse inhibitors can last from months to years, requires daily or every other day infusions of supraphysiological levels of FVIII and is effective in only up to 70% of hemophilia A patients. Preclinical and recent clinical studies have shown that gene replacement therapy with AAV vectors can effectively cure hemophilia A patients. However, it is unclear how hemophilia patients with high risk inhibitor F8 mutations or with established inhibitors will respond to gene therapy, as these patients have been excluded from ongoing clinical trials. AAV8-coF8 gene transfer in naïve BALB/c-F8e16−/Y mice (BALB/c-HA) results in anti-FVIII IgG1 inhibitors following gene transfer, which can be prevented by transient immune modulation with anti-mCD20 (18B12) and oral rapamycin. We investigated if we could improve ITI in inhibitor positive mice by combining anti-mCD20 and rapamycin with AAV8-coF8 gene therapy. Our hypothesis was that continuous expression of FVIII protein from gene transfer compared to transient FVIII from weekly protein therapy, would enhance regulatory T cell induction and promote deletion of FVIII reactive B cells, following reconstitution. Mice that received anti-CD20 had a sharp decline in inhibitors, which corresponded to FVIII memory B (Bmem) cell deletion. Importantly, only mice receiving both anti-mCD20 and rapamycin failed to increase inhibitors following rechallenge with intravenous FVIII protein therapy. Our data show that B and T cell immune modulation complements AAV8-coF8 gene therapy in naïve and inhibitor positive hemophilia A mice and suggest that such protocols should be considered for AAV gene therapy in high risk or inhibitor positive hemophilia patients.
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    Discovery and Optimization of Inhibitors of the Parkinson’s Disease Associated Protein DJ-1
    (ACS, 2018-07) Tashiro, Shinya; Caaveiro, Jose M. M.; Nakakido, Makoto; Tanabe, Aki; Nagatoishi, Satoru; Tamura, Yasushi; Matsuda, Noriyuki; Liu, Dali; Hoang, Quyen Q.; Tsumoto, Kouhei; Biochemistry and Molecular Biology, School of Medicine
    DJ-1 is a Parkinson’s disease associated protein endowed with enzymatic, redox sensing, regulatory, chaperoning, and neuroprotective activities. Although DJ-1 has been vigorously studied for the past decade and a half, its exact role in the progression of the disease remains uncertain. In addition, little is known about the spatiotemporal regulation of DJ-1, or the biochemical basis explaining its numerous biological functions. Progress has been hampered by the lack of inhibitors with precisely known mechanisms of action. Herein, we have employed biophysical methodologies and X-ray crystallography to identify and to optimize a family of compounds inactivating the critical Cys106 residue of human DJ-1. We demonstrate these compounds are potent inhibitors of various activities of DJ-1 in vitro and in cell-based assays. This study reports a new family of DJ-1 inhibitors with a defined mechanism of action, and contributes toward the understanding of the biological function of DJ-1.
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    LIM kinases: cofilin and beyond
    (Impact Journals, 2017-04-09) Prunier, Chloé; Prudent, Renaud; Kapur, Reuben; Sadoul, Karin; Lafanechère, Laurence; Pediatrics, School of Medicine
    LIM kinases are common downstream effectors of several signalization pathways and function as a signaling node that controls cytoskeleton dynamics through the phosphorylation of the cofilin family proteins. These last 10 years, several reports indicate that the functions of LIM kinases are more extended than initially described and, specifically, that LIM kinases also control microtubule dynamics, independently of their regulation of actin microfilament. In this review we analyze the data supporting these conclusions and the possible mechanisms that could be involved in the control of microtubules by LIM kinases. The demonstration that LIM kinases also control microtubule dynamics has pointed to new therapeutic opportunities. Consistently, several new LIM kinase inhibitors have been recently developed. We provide a comprehensive comparison of these inhibitors, of their chemical structure, their specificity, their cellular effects as well as their effects in animal models of various diseases including cancer.
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    MOLECULAR SCAFFOLD DEVELOPMENT OF TERTIARY AMINE CHALCONES FOR INHIBITION OF LYCOPENE CYCLASE IN FRUIT
    (Office of the Vice Chancellor for Research, 2012-04-13) Hartley, Danielle; Rickard, Timothy; Denton, Ryan
    Lycopene, a known anti-oxidant, is transformed into β-carotene and other carotenoids by a class of enzymes referred to as lycopene cyclases. Developing potential inhibitors of lycopene cyclases could yield further understanding of the structural and functional properties of these enzymes and eventually serve to manipulate lycopene levels in fruits and vegetables. Previously reported aryl tertiary amine-containing compounds, when protonated at physiological pH, act as transition-state inhibitors of these cyclizing enzymes. Our proposed scaffold yields a series of substituted chalcones containing the core structure of the known inhibitor N,N-diethyl-N-[2-(4-methylphenoxy)ethyl]amine (MPTA). However, the initial scaffold design involved the aldol condensation of a deactivated aldehyde and ketone under relatively harsh conditions. Though various methods exist for this specific transformation, we developed a novel, safe, cost-effective application of the aldol condensation using a domestic microwave and potassium carbonate with iodine impregnated alumina. Reaction conditions including catalyst, base, and microwave intensity were optimized. Herein, we report the molecular scaffold development and synthesis of several tertiary amine chalcones with the potential for activity against lycopene cyclases in fruits and vegetables.
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    Tolerance induction in hemophilia: Innovation and accomplishments
    (Wolters Kluwer, 2018-09) Sherman, Alexandra; Biswas, Moanaro; Herzog, Roland W.; Pediatrics, School of Medicine
    Purpose of review Hemophilia is an X-linked blood coagulation genetic disorder, which can cause significant disability. Replacement therapy for coagulation factor VIII (hemophilia A) or factor IX (hemophilia B) may result in the development of high-affinity alloantibodies (’inhibitors’) to the replacement therapy, thus making it ineffective. Therefore, there is interest in directing immunological responses towards tolerance to infused factors. Recent findings In this review, we will discuss latest advancements in the development of potentially less immunogenic replacement clotting factors, optimization of current tolerance induction protocols (ITI), preclinical and clinical data of pharmacological immune modulation, hepatic gene therapy, and the rapidly advancing field of cell therapies. We will also evaluate publications reporting data from preclinical studies on oral tolerance induction using chloroplast-transgenic (transplastomic) plants. Summary Until now, no clinical prophylactic immune modulatory protocol exists to prevent inhibitor formation to infused clotting factors. Recent innovative technologies provide hope for improved eradication and perhaps even prevention of inhibitors.