For a long time, superoxide generation by an NADPH oxidase was considered as an oddity only found in professional phagocytes. Over the last years, six homologs of the cytochrome subunit of the phag...

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The NOX Family of ROS-Generating NADPH Oxidases: Physiology and Pathophysiology

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

MicroRNAs (miRNAs) are an abundant class of non-coding RNAs that are believed to be important in many biological processes through regulation of gene expression. The precise molecular function of miRNAs in mammals is largely unknown and a better understanding will require loss-of-function studies in vivo. Here we show that a novel class of chemically engineered oligonucleotides, termed 'antagomirs', are efficient and specific silencers of endogenous miRNAs in mice. Intravenous administration of antagomirs against miR-16, miR-122, miR-192 and miR-194 resulted in a marked reduction of corresponding miRNA levels in liver, lung, kidney, heart, intestine, fat, skin, bone marrow, muscle, ovaries and adrenals. The silencing of endogenous miRNAs by this novel method is specific, efficient and long-lasting. The biological significance of silencing miRNAs with the use of antagomirs was studied for miR-122, an abundant liver-specific miRNA. Gene expression and bioinformatic analysis of messenger RNA from antagomir-treated animals revealed that the 3' untranslated regions of upregulated genes are strongly enriched in miR-122 recognition motifs, whereas downregulated genes are depleted in these motifs. Analysis of the functional annotation of downregulated genes specifically predicted that cholesterol biosynthesis genes would be affected by miR-122, and plasma cholesterol measurements showed reduced levels in antagomir-122-treated mice. Our findings show that antagomirs are powerful tools to silence specific miRNAs in vivo and may represent a therapeutic strategy for silencing miRNAs in disease.

https://www.gene-quantification.de/kruetzfeld-antagomirs-2005.pdf

Silencing of microRNAs in vivo with ‘antagomirs’

中枢神経系疾患の治療は正常細胞（ニューロン）の機能維持を目的とするが，脳血管障害のように機能障害の原因が細胞の死滅に基づくことは多い．一方，脳腫瘍の治療においては薬物療法や放射線療法といった腫瘍細胞の死滅を目標とするものが大きな位置を占める．いずれの場合にも，細胞死の機序を理解することは各種病態や治療法の理解のうえで重要である．現在のところ最も研究の進んでいる細胞死の型はアポトーシスである．そのなかで重要な位置を占めるミトコンドリアにおける反応および抗アポトーシス因子について概要を紹介する．

Neuroscience 細胞死：最近の知見

In the 10 years that have passed since the Nobel prize-winning discovery of RNA interference (RNAi), billions of dollars have been invested in the therapeutic application of gene silencing in humans. Today, there are promising data from ongoing clinical trials for the treatment of age-related macular degeneration and respiratory syncytial virus. Despite these early successes, however, the widespread use of RNAi therapeutics for disease prevention and treatment requires the development of clinically suitable, safe and effective drug delivery vehicles. Here, we provide an update on the progress of RNAi therapeutics and highlight novel synthetic materials for the encapsulation and intracellular delivery of nucleic acids.

Knocking down barriers: advances in siRNA delivery

Long-term cannabis use during adolescence has deleterious effects in brain that are largely ascribed to the activation of cannabinoid-1 receptors (CB1Rs) by delta-9-tetrahydrocannabinol (∆9-THC), the primary psychoactive compound in marijuana. Systemic administration of ∆9-THC inhibits acetylcholine release in the prelimbic-prefrontal cortex (PL-PFC). In turn, PL-PFC acetylcholine plays a role in executive activities regulated by CB1R-targeting endocannabinoids, which are generated by cholinergic stimulation of muscarinic-1 receptors (M1Rs). However, the long-term effects of chronic administration of increasing doses of ∆9-THC in adolescent males on the distribution and function of M1 and/or CB1 receptors in the PL-PFC remains unresolved. We used C57BL\6J male mice pre-treated with vehicle or escalating daily doses of ∆9-THC to begin filling this gap. Electron microscopic immunolabeling showed M1R-immunogold particles on plasma membranes and in association with cytoplasmic membranes in varying sized dendrites and dendritic spines. These dendritic profiles received synaptic inputs from unlabeled, CB1R- and/or M1R-labeled axon terminals in the PL-PFC of both treatment groups. However, there was a size-dependent decrease in total (plasmalemmal and cytoplasmic) M1R gold particles in small dendrites within the PL-PFC of mice receiving ∆9-THC. Whole cell current-clamp recording in PL-PFC slice preparations further revealed that adolescent pretreatment with ∆9-THC attenuates the hyperpolarization and increases the firing rate produced by local muscarinic stimulation. Repeated administration of ∆9-THC during adolescence also reduced spontaneous alternations in a Y-maze paradigm designed for measures of PFC-dependent memory function in adult mice. Our results provide new information implicating M1Rs in cortical dysfunctions resulting from adolescent abuse of marijuana.

Adolescent administration of Δ9-THC decreases the expression and function of muscarinic-1 receptors in prelimbic prefrontal cortical neurons of adult male mice.

Anorexia commonly develops in patients with advanced cancer and is closely associated with cachexia. A new study shows that anorexia emerges earlier than cachexia in both Drosophila and mouse tumour models and that tumour-derived humoral factors induce anorexia by systemically dysregulating neuropeptides in the brain.

Tumour-regulated anorexia preceding cachexia.

Polycomb repressive complex 1 (PRC1) is an essential epigenetic regulator that mainly controls histone H2A Lys119 mono-ubiquitination (H2AK119ub). BMI1 and RING1B are PRC1 core components and play critical roles in the development of various cancers. However, therapeutic agents targeting PRC1 are very limited, and small-molecule inhibitors of PRC1 displayed limited effectiveness in killing cancer cells. In this study, MS147, the first degrader of PRC1 core components, BMI1 and RING1B, was discovered via a novel protein complex degradation strategy that utilizes the target protein’s interacting partner protein (EED) to degrade BMI1 and RING1B. MS147, which comprises an EED small-molecule binder linked to a ligand of the E3 ligase VHL, degrades BMI1 and RING1B in an EED-, VHL-, ubiquitination- and time-dependent manner. MS147 is selective and preferentially degrades BMI1 and RING1B over PRC2 core components: EED, EZH2 and SUZ12. Consequently, MS147 effectively reduces H2AK119ub, but not H3K27me3, which is catalyzed by PRC2. Furthermore, MS147, but not the parent EED binder or known PRC2 degraders, effectively inhibits the proliferation of cancer cell lines that are insensitive to EZH2 knockout or PRC2 degraders. Overall, this study provides a novel degrader targeting BMI1 and RING1B, which is a useful chemical tool to further investigate the roles of PRC1 in cancer, and a novel protein complex degradation strategy, which could potentially expand the degradable human proteome.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/advs.202205573

Targeted Degradation of PRC1 Components, BMI1 and RING1B, via a Novel Protein Complex Degrader Strategy

Neurophysiology of Neurohypophysial Terminals

BACKGROUND & OBJECTIVE Various potassium channels are known to be involved in proliferation of many malignant cell lines. This study was to explore the role of voltage-gated potassium channels in proliferation of human cervical carcinoma cells through observing the effects of tetraethylammonium (TEA) on proliferation and outward potassium currents in human cervical carcinoma cell line SiHa. METHODS SiHa cells were treated with TEA. The effect of TEA on proliferation of SiHa cells was assessed by MTT assay. Cell apoptosis and cell cycle were detected by flow cytometry with Hoechst 33258 staining. The outward potassium currents were recorded by patch clamp technique. RESULTS TEA inhibited the proliferation of SiHa cells in dose-and time-dependent manners, and induced cell apoptosis. The cell cycle was arrested at G0/G1 phase after treatment with TEA. Exposure of SiHa cells to 10 mmol/L TEA reduced the peak outward potassium currents significantly from (260+/-12) pA to (58+/-6) pA (P<0.01). CONCLUSIONS Voltage-gated potassium channels play an important role in regulating proliferation of cervical carcinoma SiHa cells. Blocking voltage-gated potassium channels could inhibit proliferation of SiHa cells.

Gang Wang

Papers

Adolescent administration of Δ9-THC decreases the expression and function of muscarinic-1 receptors in prelimbic prefrontal cortical neurons of adult male mice.

Tumour-regulated anorexia preceding cachexia.

Targeted Degradation of PRC1 Components, BMI1 and RING1B, via a Novel Protein Complex Degrader Strategy

Neurophysiology of Neurohypophysial Terminals

[Inhibitory effects of tetraethylammonium on proliferation and voltage-gated potassium channels in human cervical carcinoma cell line SiHa].