- Email: [email protected]
A New Pharmacological Approach for Asthma through Tissue-Specific Modulation of the GABA(A) Receptor
Abstracts AB393
J ALLERGY CLIN IMMUNOL VOLUME 137, NUMBER 2
L13
A New Pharmacological Approach for Asthma through Tissue-Specific Modulation of the GABA(A) Receptor
Prof. Leggy A. Arnold, PhD1,2, Dr. Gloria S. Forkuo, PhD1, Ms. Amanda N. Nieman1, Ms. Olivia B. Yu1, Ms. Margaret L. Guthrie1, Ms. Nina Y. Yuan1, Ms. Revathi Kodali1, Ms. Rajwana Jahan1, Dr. Charles W. Emala3, Prof. James M. Cook, PhD1,2, Dr. Douglas C. Stafford, PhD1,2, Dr. Mitchell H. Grayson, MD FAAAAI4; 1University of Wisconsin Milwaukee, Dept. Chemistry & Biochemistry, 2Milwaukee Institute for Drug Discovery, 3Columbia University, 4Medical College of Wisconsin, Milwaukee, WI. RATIONALE: This study addresses the unmet need for an oral, safe, nonsteroidal asthma treatment by targeting GABAA receptors (GABAAR) in lung tissues. The hypothesis is that GABAARs in inflammatory and airway smooth muscle (ASM) cell can be targeted by subtype-selective GABAAR agonists to tissue-selectively induce immunosuppression and ASM relaxation. METHODS: A drug discovery approach identified GABAAR targets in lung cells by immunodetection, subtype selectivity by electrophysiology, preclinical characterization of active ligands using microsomes, S9, and blood plasma stability assays. Pharmacokinetic studies in mice are applied to identify in vivo stability and distribution. Murine pharmacodynamic models are used to quantify sensorimotor effects (rotarod), disease specific airway hyperresponsiveness, airway mucus production, and airway eosinophilia. Subtype-selective GABAAR ligands were evaluated for immune modulation using in vitro T-cell assays and ASM muscle relaxation with isolated ASM. RESULTS: The a4 subtype-selective GABAAR ligand XHE-III-74EE showed high stability in vitro but a limited half-life in vivo due to rapid metabolism and clearance. Chronic administration of 20 mg/kg XHE-III74EE successfully reduced airway hyperresponsiveness without inducing adverse CNS effects. Mucus hypersecretion was reduced for chronic and acute treatment. Similar results were observed for metabolite XHE-III74A that exhibits a4 GABAAR subtype selectivity. XHE-III-74A significantly reduced eosinophilia, which is consistent with antiinflammatory suppressive effects in activated T-cells as measured by intracellular calcium release and IL-2 production. Both compounds were able to induce ASM muscle relaxation. CONCLUSIONS: a4-Selective GABAAR agonists have a great potential as novel drug candidates for asthma to alleviate symptoms of airway hyperresponsiveness mediated by ASM constriction, hypereosinophilia, inflammation, and mucus overproduction.
L14
Role of Circulating ICOS+ Follicular Helper T Cells in the Pathogenesis of Birch Pollen Allergy
Dr Ryuta Kamekura1,2, Dr. Koji Kawata1, Mr. Sumito Jitsukawa1,2, Mr. Tomonori Nagaya1,2, Dr. Keiji Yamashita2, Mrs. Fumie Ito2, Dr. Kenichi Takano2, Dr. Katsunori Shigehara1, Prof. Tetsuo Himi2, Prof. Shingo Ichimiya1; 1Department of Human Immunology, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, 2Department of Otolaryngology, Sapporo Medical University School of Medicine. RATIONALE: Production of antigen-specific immunoglobulins in tissues is controlled by follicular helper T (Tfh) cells, which are recognized as memory Tfh cells in peripheral blood. Recent studies have revealed that inducible T-cell co-stimulator (ICOS) and programmed death 1 (PD-1) are activation molecules in blood Tfh cells. However, the role of blood Tfh cells expressing such molecules in the pathogenesis of birch pollen allergy remains unknown. METHODS: Patients with birch pollen allergy (n 5 34) and healthy controls (n 5 21) were recruited in this study. Expression of ICOS and PD1 in blood Tfh cells from subjects in pollen and pollen-free seasons (i.e. before and after the periods with pollens) was examined by flow cytometry.
Correlations between results of flow cytometry and clinical parameters were also analyzed. RESULTS: Levels of ICOS+ and/or PD-1+ in blood Tfh cells in the patients were similar to those in the controls throughout the pollen-free seasons, whereas the percentages of ICOS+ blood Tfh cells during the pollen season were temporarily increased in the patients compared to those in the controls. We also found that total symptom scores were significantly correlated with percentage of ICOS+ blood Tfh cells. Moreover, differential levels of ICOS+ blood Tfh cells in pollen- and pollen-free seasons were significantly correlated with those of birch pollen-specific IgE. CONCLUSIONS: Our findings suggest that increase in ICOS+ blood Tfh cells in response to exposure to birch pollen may underlie the pathogenesis of birch pollen allergy.
L15
Case Report of a Previously Unreported Type of DOCK8 Deficiency
Dr. Stephen Dinetz, MD, Dr. Betty B. Wray, MD FAAAAI; Medical College of Georgia, Augusta, GA. RATIONALE: Dedicator of cytokinesis 8 (DOCK8) deficiency is an autosomal recessive hyper-IgE syndrome characterized by recurrent bacterial, viral and/or fungal infections, atopic dermatitis and food allergies. Previous reports demonstrate either autosomal recessive or compound heterozygosity defects within the DOCK8 gene. METHODS: Genetic sequencing evaluation of DOCK8, SPINK5, STAT3, and TYK2 were performed by GeneDx. RESULTS: The patient presented with severe atopic dermatitis, eczema herpeticum, and severe food allergies. Immune evaluation showed decreased NK cell function, absent CD45+ total lymphocyte and CD3+ T cell responses to Tetanus toxoid and a serum IgE of 15,828 kU/L. Targeted comparative genomic hybridization revealed a heterozygous defect, c.62412 T>A, a variant of unknown significance in the DOCK8 gene. CONCLUSIONS: The c.624012 T>A variant is a previously unreported mutation that is likely responsible for the findings in this patient. This is the first reported case of this heterozygous mutation and may be clinically useful in the diagnosis and treatment of severe atopic dermatitis that does not fit the established criteria for previously reported hyper-IgE syndromes.
J ALLERGY CLIN IMMUNOL VOLUME 137, NUMBER 2
L13
A New Pharmacological Approach for Asthma through Tissue-Specific Modulation of the GABA(A) Receptor
Prof. Leggy A. Arnold, PhD1,2, Dr. Gloria S. Forkuo, PhD1, Ms. Amanda N. Nieman1, Ms. Olivia B. Yu1, Ms. Margaret L. Guthrie1, Ms. Nina Y. Yuan1, Ms. Revathi Kodali1, Ms. Rajwana Jahan1, Dr. Charles W. Emala3, Prof. James M. Cook, PhD1,2, Dr. Douglas C. Stafford, PhD1,2, Dr. Mitchell H. Grayson, MD FAAAAI4; 1University of Wisconsin Milwaukee, Dept. Chemistry & Biochemistry, 2Milwaukee Institute for Drug Discovery, 3Columbia University, 4Medical College of Wisconsin, Milwaukee, WI. RATIONALE: This study addresses the unmet need for an oral, safe, nonsteroidal asthma treatment by targeting GABAA receptors (GABAAR) in lung tissues. The hypothesis is that GABAARs in inflammatory and airway smooth muscle (ASM) cell can be targeted by subtype-selective GABAAR agonists to tissue-selectively induce immunosuppression and ASM relaxation. METHODS: A drug discovery approach identified GABAAR targets in lung cells by immunodetection, subtype selectivity by electrophysiology, preclinical characterization of active ligands using microsomes, S9, and blood plasma stability assays. Pharmacokinetic studies in mice are applied to identify in vivo stability and distribution. Murine pharmacodynamic models are used to quantify sensorimotor effects (rotarod), disease specific airway hyperresponsiveness, airway mucus production, and airway eosinophilia. Subtype-selective GABAAR ligands were evaluated for immune modulation using in vitro T-cell assays and ASM muscle relaxation with isolated ASM. RESULTS: The a4 subtype-selective GABAAR ligand XHE-III-74EE showed high stability in vitro but a limited half-life in vivo due to rapid metabolism and clearance. Chronic administration of 20 mg/kg XHE-III74EE successfully reduced airway hyperresponsiveness without inducing adverse CNS effects. Mucus hypersecretion was reduced for chronic and acute treatment. Similar results were observed for metabolite XHE-III74A that exhibits a4 GABAAR subtype selectivity. XHE-III-74A significantly reduced eosinophilia, which is consistent with antiinflammatory suppressive effects in activated T-cells as measured by intracellular calcium release and IL-2 production. Both compounds were able to induce ASM muscle relaxation. CONCLUSIONS: a4-Selective GABAAR agonists have a great potential as novel drug candidates for asthma to alleviate symptoms of airway hyperresponsiveness mediated by ASM constriction, hypereosinophilia, inflammation, and mucus overproduction.
L14
Role of Circulating ICOS+ Follicular Helper T Cells in the Pathogenesis of Birch Pollen Allergy
Dr Ryuta Kamekura1,2, Dr. Koji Kawata1, Mr. Sumito Jitsukawa1,2, Mr. Tomonori Nagaya1,2, Dr. Keiji Yamashita2, Mrs. Fumie Ito2, Dr. Kenichi Takano2, Dr. Katsunori Shigehara1, Prof. Tetsuo Himi2, Prof. Shingo Ichimiya1; 1Department of Human Immunology, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, 2Department of Otolaryngology, Sapporo Medical University School of Medicine. RATIONALE: Production of antigen-specific immunoglobulins in tissues is controlled by follicular helper T (Tfh) cells, which are recognized as memory Tfh cells in peripheral blood. Recent studies have revealed that inducible T-cell co-stimulator (ICOS) and programmed death 1 (PD-1) are activation molecules in blood Tfh cells. However, the role of blood Tfh cells expressing such molecules in the pathogenesis of birch pollen allergy remains unknown. METHODS: Patients with birch pollen allergy (n 5 34) and healthy controls (n 5 21) were recruited in this study. Expression of ICOS and PD1 in blood Tfh cells from subjects in pollen and pollen-free seasons (i.e. before and after the periods with pollens) was examined by flow cytometry.
Correlations between results of flow cytometry and clinical parameters were also analyzed. RESULTS: Levels of ICOS+ and/or PD-1+ in blood Tfh cells in the patients were similar to those in the controls throughout the pollen-free seasons, whereas the percentages of ICOS+ blood Tfh cells during the pollen season were temporarily increased in the patients compared to those in the controls. We also found that total symptom scores were significantly correlated with percentage of ICOS+ blood Tfh cells. Moreover, differential levels of ICOS+ blood Tfh cells in pollen- and pollen-free seasons were significantly correlated with those of birch pollen-specific IgE. CONCLUSIONS: Our findings suggest that increase in ICOS+ blood Tfh cells in response to exposure to birch pollen may underlie the pathogenesis of birch pollen allergy.
L15
Case Report of a Previously Unreported Type of DOCK8 Deficiency
Dr. Stephen Dinetz, MD, Dr. Betty B. Wray, MD FAAAAI; Medical College of Georgia, Augusta, GA. RATIONALE: Dedicator of cytokinesis 8 (DOCK8) deficiency is an autosomal recessive hyper-IgE syndrome characterized by recurrent bacterial, viral and/or fungal infections, atopic dermatitis and food allergies. Previous reports demonstrate either autosomal recessive or compound heterozygosity defects within the DOCK8 gene. METHODS: Genetic sequencing evaluation of DOCK8, SPINK5, STAT3, and TYK2 were performed by GeneDx. RESULTS: The patient presented with severe atopic dermatitis, eczema herpeticum, and severe food allergies. Immune evaluation showed decreased NK cell function, absent CD45+ total lymphocyte and CD3+ T cell responses to Tetanus toxoid and a serum IgE of 15,828 kU/L. Targeted comparative genomic hybridization revealed a heterozygous defect, c.62412 T>A, a variant of unknown significance in the DOCK8 gene. CONCLUSIONS: The c.624012 T>A variant is a previously unreported mutation that is likely responsible for the findings in this patient. This is the first reported case of this heterozygous mutation and may be clinically useful in the diagnosis and treatment of severe atopic dermatitis that does not fit the established criteria for previously reported hyper-IgE syndromes.