benzofurans and Autoimmune-Diseases

Changes in thyroid function may occur during treatment with amiodarone. A double blind prospective trial of amiodarone and placebo was performed in 37 patients in the subacute phase of myocardial infarction. Though none of the patients assigned to receive placebo developed any antibody, six of 13 patients treated with amiodarone developed antithyroid microsomal antibodies. There was no difference in triiodothyronine and thyroxine concentrations between the two groups, but a significant difference in concentrations of thyroid stimulating hormone was noted on day 30 (p less than 0.05). Six months after the withdrawal of amiodarone autoantibodies could not be detected and concentrations of thyroid stimulating hormone were normal. These antibodies have not previously been reported to develop during short term treatment with amiodarone. They could have an important role in the detection of early thyroid changes in patients given amiodarone.

Topics: Adult; Aged; Amiodarone; Antibody Formation; Autoantibodies; Autoimmune Diseases; Benzofurans; Double-Blind Method; Female; Humans; Male; Microsomes; Middle Aged; Myocardial Infarction; Prospective Studies; Thyroid Diseases; Thyroid Gland; Thyrotropin

Cyclic GMP-AMP synthase is essential for innate immunity against infection and cellular damage, serving as a sensor of DNA from pathogens or mislocalized self-DNA. Upon binding double-stranded DNA, cyclic GMP-AMP synthase synthesizes a cyclic dinucleotide that initiates an inflammatory cellular response. Mouse studies that recapitulate causative mutations in the autoimmune disease Aicardi-Goutières syndrome demonstrate that ablating the cyclic GMP-AMP synthase gene abolishes the deleterious phenotype. Here, we report the discovery of a class of cyclic GMP-AMP synthase inhibitors identified by a high-throughput screen. These compounds possess defined structure-activity relationships and we present crystal structures of cyclic GMP-AMP synthase, double-stranded DNA, and inhibitors within the enzymatic active site. We find that a chemically improved member, RU.521, is active and selective in cellular assays of cyclic GMP-AMP synthase-mediated signaling and reduces constitutive expression of interferon in macrophages from a mouse model of Aicardi-Goutières syndrome. RU.521 will be useful toward understanding the biological roles of cyclic GMP-AMP synthase and can serve as a molecular scaffold for development of future autoimmune therapies.Upon DNA binding cyclic GMP-AMP synthase (cGAS) produces a cyclic dinucleotide, which leads to the upregulation of inflammatory genes. Here the authors develop small molecule cGAS inhibitors, functionally characterize them and present the inhibitor and DNA bound cGAS crystal structures, which will facilitate drug development.

Topics: Animals; Autoimmune Diseases; Autoimmune Diseases of the Nervous System; Autoimmunity; Benzofurans; DNA; Enzyme Inhibitors; High-Throughput Screening Assays; Immunity, Innate; Inflammation; Macrophages; Mass Spectrometry; Mice; Nervous System Malformations; Nucleotidyltransferases; Small Molecule Libraries; Structure-Activity Relationship

Activation of the B-cell antigen receptor (BCR) signaling pathway contributes to the initiation and maintenance of B-cell malignancies and autoimmune diseases. The Bruton tyrosine kinase (Btk) is specifically required for BCR signaling as demonstrated by human and mouse mutations that disrupt Btk function and prevent B-cell maturation at steps that require a functional BCR pathway. Herein we describe a selective and irreversible Btk inhibitor, PCI-32765, that is currently under clinical development in patients with B-cell non-Hodgkin lymphoma. We have used this inhibitor to investigate the biologic effects of Btk inhibition on mature B-cell function and the progression of B cell-associated diseases in vivo. PCI-32765 blocked BCR signaling in human peripheral B cells at concentrations that did not affect T cell receptor signaling. In mice with collagen-induced arthritis, orally administered PCI-32765 reduced the level of circulating autoantibodies and completely suppressed disease. PCI-32765 also inhibited autoantibody production and the development of kidney disease in the MRL-Fas(lpr) lupus model. Occupancy of the Btk active site by PCI-32765 was monitored in vitro and in vivo using a fluorescent affinity probe for Btk. Active site occupancy of Btk was tightly correlated with the blockade of BCR signaling and in vivo efficacy. Finally, PCI-32765 induced objective clinical responses in dogs with spontaneous B-cell non-Hodgkin lymphoma. These findings support Btk inhibition as a therapeutic approach for the treatment of human diseases associated with activation of the BCR pathway.

Topics: Adenine; Administration, Oral; Agammaglobulinaemia Tyrosine Kinase; Animals; Arthritis, Experimental; Autoantibodies; Autoimmune Diseases; B-Lymphocytes; Benzofurans; Disease Models, Animal; Dogs; Humans; Lymphocyte Activation; Lymphoma, B-Cell; Mice; Piperidines; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyrazoles; Pyrimidines; Receptors, Antigen, B-Cell; Signal Transduction; Treatment Outcome

The lymphoid-specific tyrosine phosphatase (Lyp) has generated enormous interest because a single-nucleotide polymorphism in the gene (PTPN22) encoding Lyp produces a gain-of-function mutant phosphatase that is associated with several autoimmune diseases, including type I diabetes, rheumatoid arthritis, Graves disease, and systemic lupus erythematosus. Thus, Lyp represents a potential target for a broad spectrum of autoimmune disorders. Unfortunately, no Lyp inhibitor has been reported. In addition, little is known about the structure and biochemical mechanism that directly regulates Lyp function. Here, we report the identification of a bidentate salicylic acid-based Lyp inhibitor I-C11 with excellent cellular efficacy. Structural and mutational analyses indicate that the inhibitor binds both the active site and a nearby peripheral site unique to Lyp, thereby furnishing a solid foundation upon which inhibitors with therapeutic potency and selectivity can be developed. Moreover, a comparison of the apo- and inhibitor-bound Lyp structures reveals that the Lyp-specific region S(35)TKYKADK(42), which harbors a PKC phosphorylation site, could adopt either a loop or helical conformation. We show that Lyp is phosphorylated exclusively at Ser-35 by PKC both in vitro and in vivo. We provide evidence that the status of Ser-35 phosphorylation may dictate the conformational state of the insert region and thus Lyp substrate recognition. We demonstrate that Ser-35 phosphorylation impairs Lyp's ability to inactivate the Src family kinases and down-regulate T cell receptor signaling. Our data establish a mechanism by which PKC could attenuate the cellular function of Lyp, thereby augmenting T cell activation.

Topics: Amino Acid Sequence; Autoimmune Diseases; Benzofurans; Crystallography, X-Ray; Enzyme Inhibitors; Humans; Inhibitory Concentration 50; Jurkat Cells; Kinetics; Lymphocyte Activation; Models, Molecular; Molecular Structure; Mutation; Phosphorylation; Phosphoserine; Protein Kinase C; Protein Structure, Tertiary; Protein Tyrosine Phosphatase, Non-Receptor Type 22; Receptors, Antigen, T-Cell; Sequence Alignment; Signal Transduction; Substrate Specificity; T-Lymphocytes; Triazoles

Lambert-Eaton syndrome, an autoimmune disorder frequently associated with small-cell carcinoma of the lung, is characterized by impaired evoked release of acetylcholine from the motor nerve terminal. Immunoglobulin G (IgG) antibodies from patients with the syndrome, applied to bovine adrenal chromaffin cells, reduced the voltage-dependent calcium channel currents by about 40 percent. When calcium was administered directly into the cytoplasm, however, the IgG-treated cells exhibited normal exocytotic secretion, as assayed by membrane capacitance measurement. Measurement with the fluorescent calcium indicator fura-2 indicated that the IgG treatment reduced potassium-stimulated increase in free intracellular calcium concentration. The pathogenic IgG modified neither kinetics of calcium channel activation nor elementary channel activity, suggesting that a reduction in the number of functional calcium channels underlies the IgG-induced effect. Therefore, Lambert-Eaton syndrome IgG reacts with voltage-dependent calcium channels and blocks their function, a phenomenon that can account for the presynaptic impairment characteristic of this disorder.

Topics: Adrenal Glands; Autoantibodies; Autoimmune Diseases; Benzofurans; Calcium; Carcinoma, Small Cell; Cell Membrane; Chromaffin System; Electric Conductivity; Exocytosis; Fluorescent Dyes; Fura-2; Humans; Immunoglobulin G; Ion Channels; Lung Neoplasms; Neuromuscular Diseases; Sodium; Synapses; Syndrome; Tetrodotoxin

T cell subsets in 10 patients receiving amiodarone were evaluated, and their thyroid function and antithyroid antibodies were assessed. A generalized increase in a recently discovered subset of T cells expressing a complex ganglioside antigen reacting with monoclonal antibody 3G5 was found. Two patients, one with hyperthyroidism and the other with euthyroid Graves' ophthalmopathy, had an additional T cell abnormality--marked increase in Ia-positive T cells (an abnormality typical of patients with spontaneous Graves' disease). In the hyperthyroid patient, the Ia-positive T cells disappeared within three weeks after amiodarone was discontinued. The other patients receiving amiodarone had normal numbers of Ia-positive T cells. These studies indicate that amiodarone alters a major resting T cell subset for almost all patients and is associated with T cells expressing the Ia antigen in selected patients. These T cell abnormalities suggest that amiodarone precipitates organ-specific autoimmunity in susceptible persons.

Topics: Adult; Aged; Amiodarone; Antibodies, Monoclonal; Autoantibodies; Autoimmune Diseases; Benzofurans; Female; Flow Cytometry; Histocompatibility Antigens Class II; Humans; Male; Microsomes; Middle Aged; T-Lymphocytes; Thyroglobulin; Thyroid Diseases; Thyroid Gland