Synthesis and Metabolism of Drugs by Means of Enzyme-Catalysed Reactions

The usefulness of enzyme catalysed-reactions is exemplified by recent results from research at Roche.Sequences of enzyme reactions, well organised in metabolic pathways of selected microorganisms, lead to secondary metabolites with innovative chemical structures. An example is the pancreas-lipase inhibitor lipstatin produced by Streptomyces toxytricini. Hydrogenation of lipstatin yields tetrahydrolipstatin, the active substance of the anti-obesity drug Xenical™. The biosynthetic pathway has been elucidated and an improved fermentation process for the production of lipstatin has been developed.Intermediates of the primary metabolism can be valuable building blocks for the chemical synthesis of drugs. Examples are quinic acid and shikimic acid, which are both suitable starting materials for the synthesis of the neuraminidase inhibitor GS 4104. Metabolic engineering of Escherichia coli with the goal to overproduce these two substances is briefly described.Microorganisms or enzymes derived thereof are used in drug synthesis to catalyse single, highly specific reaction steps (biotransformations). Three examples yielding chiral precursors of a protein-kinase inhibitor, a collagenase inhibitor, and an antifungal compound are discussed.Recombinant Escherichia coli strains expressing human drug-metabolising enzymes are suited to mimic drug metabolism and to produce intermediates of human drug metabolism. The desired hydroxylated drug derivatives could be obtained after incubation of drug substances with strains coexpressing one specific human cytochrome P450 isozyme together with human reductase

ATP Release from Dying Autophagic Cells and Their Phagocytosis Are Crucial for Inflammasome Activation in Macrophages

Pathogen-activated and damage-associated molecular patterns activate the inflammasome in macrophages. We report that mouse macrophages release IL-1β while co-incubated with pro-B (Ba/F3) cells dying, as a result of IL-3 withdrawal, by apoptosis with autophagy, but not when they are co-incubated with living, apoptotic, necrotic or necrostatin-1 treated cells. NALP3-deficient macrophages display reduced IL-1β secretion, which is also inhibited in macrophages deficient in caspase-1 or pre-treated with its inhibitor. This finding demonstrates that the inflammasome is activated during phagocytosis of dying autophagic cells. We show that activation of NALP3 depends on phagocytosis of dying cells, ATP release through pannexin-1 channels of dying autophagic cells, P2X7 purinergic receptor activation, and on consequent potassium efflux. Dying autophagic Ba/F3 cells injected intraperitoneally in mice recruit neutrophils and thereby induce acute inflammation. These findings demonstrate that NALP3 performs key upstream functions in inflammasome activation in mouse macrophages engulfing dying autophagic cells, and that these functions lead to pro-inflammatory responses

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

Genome-wide association study in alopecia areata implicates both innate and adaptive immunity.

Alopecia areata (AA) is among the most highly prevalent human autoimmune diseases, leading to disfiguring hair loss due to the collapse of immune privilege of the hair follicle and subsequent autoimmune attack1,2. The genetic basis of AA is largely unknown. We undertook a genome-wide association study (GWAS) in a sample of 1,054 cases and 3,278 controls and identified 139 single nucleotide polymorphisms that are significantly associated with AA (P ≤ 5 × 10(−7)). Here we show an association with genomic regions containing several genes controlling the activation and proliferation of regulatory T cells (T(reg) cells), cytotoxic T lymphocyte-associated antigen 4 (CTLA4), interleukin (IL)-2/IL-21, IL-2 receptor A (IL-2RA; CD25) and Eos (also known as Ikaros family zinc finger 4; IKZF4), as well as the human leukocyte antigen (HLA) region. We also find association evidence for regions containing genes expressed in the hair follicle itself (PRDX5 and STX17). A region of strong association resides within the ULBP (cytomegalovirus UL16-binding protein) gene cluster on chromosome 6q25.1, encoding activating ligands of the natural killer cell receptor NKG2D that have not previously been implicated in an autoimmune disease. By probing the role of ULBP3 in disease pathogenesis, we also show that its expression in lesional scalp from patients with AA is markedly upregulated in the hair follicle dermal sheath during active disease. This study provides evidence for the involvement of both innate and acquired immunity in the pathogenesis of AA. We have defined the genetic underpinnings of AA, placing it within the context of shared pathways among autoimmune diseases, and implicating a novel disease mechanism, the upregulation of ULBP ligands, in triggering autoimmunity