Aminoadamantanes containing monoterpene-derived fragments as potent tyrosyl-DNA phosphodiesterase 1 inhibitors

The ability of a number of nitrogen-containing compounds that simultaneously carry the adamantane and monoterpene moieties to inhibit Tdp1, an important enzyme of the DNA repair system, is studied. Inhibition of this enzyme has the potential to overcome chemotherapeutic resistance of some tumor types. Compound (+)-3c synthesized from 1-aminoadamantane and (+)-myrtenal, and compound 4a produced from 2-aminoadamantane and citronellal were found to be most potent as they inhibited Tdp1 with IC₅₀ values of 6 and 3.5 µM, respectively. These compounds proved to have low cytotoxicity in colon HCT-116 and lung A-549 human tumor cell lines (CC₅₀ > 50 µM). It was demonstrated that compound 4a at 10 µM enhanced cytotoxicity of topotecan, a topoisomerase 1 poison in clinical use, against HCT-116 more than fivefold and to a lesser extent of 1.5 increase in potency for A-549.     

Photoproduction of hydrogen, nitrogenase and hydrogenase activities of free and immobilized whole cells of Rhodobacter sphaeroides O.U. 001

Abstract Photoproduction of hydrogen, nitrogenase activity (acetylene reduction) and hydrogenase activity (methylene blue dye reduction) were studied in free and alginate immobilized whole cells of a purple non-sulfur photosynthetic bacterium Rhodobacter sphaeroides O.U. 001. Four-fold increase in hydrogen production, two-fold increase in nitrogenase activity and 1.2-fold increase in the hydrogenase activity were observed in immobilized cells compared to free cells. Effect of various inhibitors (CO and C₂H₂) and electron donor (H₂) on the above three functions by free and immobilized cells has also been studied.     

Assessment and comparison of neural morphology through metrical feature extraction and analysis in neuron and neuron–glia cultures

The morphology of dissociated single cerebellar Purkinje cells obtained from wild-type P1 CD1 mice was assessed in the absence and in the presence of glia. A dedicated noninvasive technique based on optical microscopy was developed. Image processing algorithms were implemented to extract metrical features characterizing cell structure and dendritic arborization. The morphological features were analyzed in order to identify quantitative differences in Purkinje cell morphology due to interactions with astrocytes.     

Hypoxia-inducible factor 1α regulates branching morphogenesis during kidney development

The kidneys are exposed to hypoxic conditions during development. Hypoxia-inducible factor (HIF), an important mediator of the response to hypoxia, is believed to have an important role in development. However, the relationship between HIF and branching morphogenesis has not been elucidated clearly.     

ROCKing cytokine secretion balance in human T cells

Balanced regulation of cytokine secretion in T cells is critical for maintenance of immune homeostasis and prevention of autoimmunity. The Rho-associated kinase (ROCK) 2 signaling pathway was previously shown to be involved in controlling of cellular movement and shape. However, recent work from our group and others has demonstrated a new and important role of ROCK2 in regulating cytokine secretion in T cells. We found that ROCK2 promotes pro-inflammatory cytokines such as IL-17 and IL-21, whereas IL-2 and IL-10 secretion are negatively regulated by ROCK2 under Th17-skewing activation. Also, in disease, but not in steady state conditions, ROCK2 contributes to regulation of IFN-γ secretion in T cells from rheumatoid arthritis patients. Thus, ROCK2 signaling is a key pathway in modulation of T-cell mediated immune responses underscoring the therapeutic potential of targeted inhibition of ROCK2 in autoimmunity.     

Carbonic anhydrase inhibition blocks skeletogenesis and echinochrome production in Paracentrotus lividus and Heliocidaris tuberculata embryos and larvae

Carbonic anhydrases (CAs) are a family of widely distributed metalloenzymes, involved in diverse physiological processes. These enzymes catalyse the reversible conversion of carbon dioxide to protons and bicarbonate. At least 19 genes encoding for CAs have been identified in the sea urchin genome, with one of these localized to the skeletogenic mesoderm (primary mesenchyme cells, PMCs). We investigated the effects of a specific inhibitor of CA, acetazolamide (AZ), on development of two sea urchin species with contrasting investment in skeleton production, Paracentrotus lividus and Heliocidaris tuberculata, to determine the role of CA on PMC differentiation, skeletogenesis and on non‐skeletogenic mesodermal (NSM) cells. Embryos were cultured in the presence of AZ from the blastula stage prior to skeleton formation and development to the larval stage was monitored. At the dose of 8 mmol/L AZ, 98% and 90% of P. lividus and H. tuberculata embryos lacked skeleton, respectively. Nevertheless, an almost normal PMC differentiation was indicated by the expression of msp130, a PMC‐specific marker. Strikingly, the AZ‐treated embryos also lacked the echinochrome pigment produced by the pigment cells, a subpopulation of NSM cells with immune activities within the larva. Conversely, all ectoderm and endoderm derivatives and other subpopulations of mesoderm developed normally. The inhibitory effects of AZ were completely reversed after removal of the inhibitor from the medium. Our data, together with new information concerning the involvement of CA on skeleton formation, provide evidence for the first time of a possible role of the CAs in larval immune pigment cells.     

Hypoxia facilitates the survival of nucleus pulposus cells in serum deprivation by down-regulating excessive autophagy through restricting ROS generation

Nucleus pulposus (NP) cells reside in a hypoxic environment in vivo, while the mechanisms of how NP cells maintain survival under hypoxia are not clear. Autophagy is an important physiological response to hypoxia and implicated in the survival regulation in most types of cells. This study was designed to investigate the role of autophagy in the survival of NP cells under hypoxia. We found that appropriate autophagy activity was beneficial to the survival of NP cells in serum deprivation, while excessive autophagy led to death of the NP cells. Hypoxia facilitated the survival of NP cells in serum deprivation by down-regulating excessive autophagy. Hypoxia down-regulated the autophagy activity of NP cells through restricting the production of reactive oxygen species (ROS) and inactivating the AMPK/mTOR signaling pathway, and possibly through a pathway involving HIF-1α. We believed that understanding the autophagy response of NP cells to hypoxia and its role in cell survival had important clinical significance in the prevention and treatment of degenerative discogenic diseases.     

1H, 13C and 15N resonance assignment of phage T4 endoribonuclease RegB

RegB is involved in the control of the phage T4 life cycle. It inactivates the phage early mRNAs when their translation is no more required. We determined its structure and identified residues involved in substrate binding. For this, all backbone and 90% of side-chain resonance frequencies were assigned.     

Radioiodinated surface proteins of rabbit trophectoderm cells

Summary We have previously used surface iodination to discriminate between the protein patterns of epithelial cell surfaces in uteri of rabbits receptive (Day 6.5) or nonreceptive (Day 4) to nidation (Ricketts et al. 1984). In this paper, we describe application of the same technique to the trophoblastic surface of rabbit blastocysts collected on the same days of pregnancy. Analysis of labelled proteins by polyacrylamide-gel electrophoresis under denaturing conditions did not reveal qualitative differences between the two days of pregnancy. Scanning densitometry was used to quantitate the area under each protein peak on an autoradiogram; these areas were used as variables in statistical analysis of the protein pattern of individual animals. Quantitative differences between the protein patterns of the two surfaces were detected by canonical variate analysis of the pattern of relative areas of labelled protein peaks. In proteins separated on 7.5% gels, this statistical analysis correctly assigned blastocysts from 8 out of 10 animals to one of two groups according to day of pregnancy. The discrimination was not statistically significant, however, in protein patterns on 12.5% gels, used to give better separation in the lower range of molecular weights. The same analysis in the uterus unequivocally separated the surface iodination patterns from these same days of pregnancy. Thus the changes detected by surface iodination appear to be less pronounced on the trophectoderm than on the uterine epithelium in relation to the time of ovoimplantation.     

溶血磷脂酸在皮肤损伤疾病中的作用及其分子机制

皮肤作为人体最大器官覆盖于全身,能阻挡有害物质的侵入,保护人体内环境稳态,参与人体代谢过程。皮肤损伤、炎症和纤维化等,都会导致皮肤屏障功能的减退,影响正常的生命活动。溶血磷脂酸(lysophosphatidic acid,LPA)是十分活跃的磷脂信号分子,参与多种生理和病理生理过程。LPA是维持体内平衡所必需的生物活性脂质介质,在皮肤中通过不同的信号通路发挥多功能磷脂信使作用。本文综述了皮肤中溶血磷脂酸受体(lysophosphatidic acid receptor,LPA1-6)及其细胞信号通路的作用及机制,综述了LPA在皮肤创面愈合、皮肤瘢痕、皮肤黑色素瘤、硬皮病、皮肤瘙痒、过敏性皮炎、皮肤屏障、皮肤疼痛,皮肤毛发生长中的作用及分子机制,有助于了解LPA在皮肤中的生理和病理生理作用。深入研究LPA的作用机制将有助于挖掘其在皮肤治疗中的作用,开发以LPA为靶点的药物。