The discovery that mammalian cells have the ability to synthesize the free radical nitric oxide (NO) has stimulated an extraordinary impetus for scientific research in all the fields of biology and medicine. Since its early description as an endothelial-derived relaxing factor, NO has emerged as a fundamental signaling device regulating virtually every critical cellular function, as well as a potent mediator of cellular damage in a wide range of conditions. Recent evidence indicates that most of the cytotoxicity attributed to NO is rather due to peroxynitrite, produced from the diffusion-controlled reaction between NO and another free radical, the superoxide anion. Peroxynitrite interacts with lipids, DNA, and proteins via direct oxidative reactions or via indirect, radical-mediated mechanisms. These reactions trigger cellular responses ranging from subtle modulations of cell signaling to overwhelming oxidative injury, committing cells to necrosis or apoptosis. In vivo, peroxynitrite generation represents a crucial pathogenic mechanism in conditions such as stroke, myocardial infarction, chronic heart failure, diabetes, circulatory shock, chronic inflammatory diseases, cancer, and neurodegenerative disorders. Hence, novel pharmacological strategies aimed at removing peroxynitrite might represent powerful therapeutic tools in the future. Evidence supporting these novel roles of NO and peroxynitrite is presented in detail in this review.

/pdf/nitric-oxide-and-peroxynitrite-in-health-and-disease-3uuuqgfdcz.pdf

Nitric Oxide and Peroxynitrite in Health and Disease

Biochemical, electrophysiological, and pharmacological evidence supporting a role for cholinergic dysfunction in age-related memory disturbances is critically reviewed. An attempt has been made to identify pseudoissues, resolve certain controversies, and clarify misconceptions that have occurred in the literature. Significant cholinergic dysfunctions occur in the aged and demented central nervous system, relationships between these changes and loss of memory exist, similar memory deficits can be artificially induced by blocking cholinergic mechanisms in young subjects, and under certain tightly controlled conditions reliable memory improvements in aged subjects can be achieved after cholinergic stimulation. Conventional attempts to reduce memory impairments in clinical trials hav not been therapeutically successful, however. Possible explanations for these disappointments are given and directions for future laboratory and clinical studies are suggested.

https://science.sciencemag.org/content/sci/217/4558/408.full.pdf

The Cholinergic Hypothesis of Geriatric Memory Dysfunction

Inflammation and Alzheimer's disease.

Shared principles in NF-kappaB signaling

Irrespective of the morphological features of end-stage cell death (that may be apoptotic, necrotic, autophagic, or mitotic), mitochondrial membrane permeabilization (MMP) is frequently the decisive event that delimits the frontier between survival and death. Thus mitochondrial membranes constitute the battleground on which opposing signals combat to seal the cell's fate. Local players that determine the propensity to MMP include the pro- and antiapoptotic members of the Bcl-2 family, proteins from the mitochondrialpermeability transition pore complex, as well as a plethora of interacting partners including mitochondrial lipids. Intermediate metabolites, redox processes, sphingolipids, ion gradients, transcription factors, as well as kinases and phosphatases link lethal and vital signals emanating from distinct subcellular compartments to mitochondria. Thus mitochondria integrate a variety of proapoptotic signals. Once MMP has been induced, it causes the release of catabolic hydrolases and activators of such enzymes (including those of caspases) from mitochondria. These catabolic enzymes as well as the cessation of the bioenergetic and redox functions of mitochondria finally lead to cell death, meaning that mitochondria coordinate the late stage of cellular demise. Pathological cell death induced by ischemia/reperfusion, intoxication with xenobiotics, neurodegenerative diseases, or viral infection also relies on MMP as a critical event. The inhibition of MMP constitutes an important strategy for the pharmaceutical prevention of unwarranted cell death. Conversely, induction of MMP in tumor cells constitutes the goal of anticancer chemotherapy.

Mitochondrial Membrane Permeabilization in Cell Death

https://www.cell.com/trends/biochemical-sciences/pdf/S0968-0004(03)00320-7.pdf

The glamour and gloom of glycogen synthase kinase-3.

The multifaceted roles of glycogen synthase kinase 3beta in cellular signaling.

Glycogen synthase kinase-3 (GSK3): Regulation, actions, and diseases

The cellular mechanisms that directly regulate the inflammatory response after Toll-like receptor (TLR) stimulation are unresolved at present. Here we report that glycogen synthase kinase 3 (GSK3) differentially regulates TLR-mediated production of pro- and anti-inflammatory cytokines. Stimulation of monocytes or peripheral blood mononuclear cells with TLR2, TLR4, TLR5 or TLR9 agonists induced substantial increases in interleukin 10 production while suppressing the release of proinflammatory cytokines after GSK3 inhibition. GSK3 regulated the inflammatory response by differentially affecting the nuclear amounts of transcription factors NF-κB subunit p65 and CREB interacting with the coactivator CBP. Administration of a GSK3 inhibitor potently suppressed the proinflammatory response in mice receiving lipopolysaccharide and mediated protection from endotoxin shock. These findings demonstrate a regulatory function for GSK3 in modulating the inflammatory response.

Toll-like receptor—mediated cytokine production is differentially regulated by glycogen synthase kinase 3

Deciphering what governs inflammation and its effects on tissues is vital for understanding many pathologies. The recent discovery that glycogen synthase kinase-3 (GSK3) promotes inflammation reveals a new component of its well-documented actions in several prevalent diseases which involve inflammation, including mood disorders, Alzheimer’s disease, diabetes, and cancer. Involvement in such disparate conditions stems from the widespread influences of GSK3 on many cellular functions, with this review focusing on its regulation of inflammatory processes. GSK3 promotes the production of inflammatory molecules and cell migration, which together make GSK3 a powerful regulator of inflammation, while GSK3 inhibition provides protection from inflammatory conditions in animal models. The involvement of GSK3 and inflammation in these diseases are highlighted. Thus, GSK3 may contribute not only to primary pathologies in these diseases, but also to the associated inflammation, suggesting that GSK3 inhibitors may have multiple effects influencing these conditions.

Richard S. Jope

Papers

The glamour and gloom of glycogen synthase kinase-3.

The multifaceted roles of glycogen synthase kinase 3beta in cellular signaling.

Glycogen synthase kinase-3 (GSK3): Regulation, actions, and diseases

Toll-like receptor—mediated cytokine production is differentially regulated by glycogen synthase kinase 3

Glycogen Synthase Kinase-3 (GSK3): Inflammation, Diseases, and Therapeutics