Network analyses identify liver‐specific targets for treating liver diseases

We performed integrative network analyses to identify targets that can be used for effectively treating liver diseases with minimal side effects. We first generated co‐expression networks (CNs) for 46 human tissues and liver cancer to explore the functional relationships between genes and examined the overlap between functional and physical interactions. Since increased de novo lipogenesis is a characteristic of nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC), we investigated the liver‐specific genes co‐expressed with fatty acid synthase (FASN). CN analyses predicted that inhibition of these liver‐specific genes decreases FASN expression. Experiments in human cancer cell lines, mouse liver samples, and primary human hepatocytes validated our predictions by demonstrating functional relationships between these liver genes, and showing that their inhibition decreases cell growth and liver fat content. In conclusion, we identified liver‐specific genes linked to NAFLD pathogenesis, such as pyruvate kinase liver and red blood cell (PKLR), or to HCC pathogenesis, such as PKLR, patatin‐like phospholipase domain containing 3 (PNPLA3), and proprotein convertase subtilisin/kexin type 9 (PCSK9), all of which are potential targets for drug development.     

Clathrin-independent endocytosis of GABA(A) receptors in HEK 293 cells.

The endocytosis of GABA(A) receptors was investigated in HEK 293 cells expressing receptor alpha1beta2- and alpha1beta2gamma2-subunit combinations. For assessment of internalized receptors by radioimmunoassay or immunofluorescence, a triple c-myc epitope was introduced into the amino terminus of the beta2 subunit. An assay based on biotin inaccessibility was used for alpha1 subunits. GABA(A) alpha1beta2- and alpha1beta2gamma2-subunit receptors were internalized with a t(1/2) of 5.5 min at 37 degrees C. With both subunit combinations, phorbol 12-myristate 3-acetate enhanced internalization by nearly 100%. Treatment of the cells with hypertonic sucrose prevented both the basal and phorbol ester-induced endocytosis of GABA(A) receptors. GF 109203X, an inhibitor of protein kinase C, blocked the stimulation by phorbol ester but had no detectable effect on basal receptor endocytosis. Coexpression with a dominant-negative mutant of dynamin (K44A) led to a 100% enhancement of GABA(A) receptor internalization, while the endocytosis of beta(2)-adrenergic receptors was completely prevented. The results indicate that the endocytosis of GABA(A) alpha1beta2-subunit receptors in HEK cells is constitutive, positively modulated by activation of protein kinase C, and occurs by a mechanism that requires neither the participation of a GABA(A) receptor gamma2 subunit nor a clathrin-mediated pathway.     

The EGL-13 SOX domain transcription factor affects the uterine pi cell lineages in Caenorhabditis elegans

We isolated egl-13 mutants in which the pi cells of the Caenorhabditis elegans uterus initially appeared to develop normally but then underwent an extra round of cell division. The data suggest that egl-13 is required for maintenance of the pi cell fate.     

Functional androgen receptor confers sensitization of androgen-independent prostate cancer cells to anticancer therapy via caspase activation

Therapeutic resistance remains an unresolved problem in the clinical management of human prostate cancer (PC). Despite initial positive response to androgen ablation therapy (AAT), virtually all PC patients will relapse due to acquisition of hormone refractory disease and selective outgrowth of tumor cells with multidrug resistance phenotype. We here provide the first experimental evidence that restoring a functional androgen receptor (AR) in the androgen-independent prostate cancer PC3 cells enhances their sensitivity to growth arrest and suppresses their colony-forming ability in response to paclitaxel and gamma-irradiation. Furthermore, functional AR increases the susceptibility of these cells to the apoptotic potentials of therapeutic agents, as evidenced by an increase in caspase activity, annexin V binding, and internucleosomal DNA fragmentation, by inducing caspase activation. The abrogation of the cytotoxic effects by 4-hydroxyflutamide suggests a crucial role for AR activation in enhancing the therapeutic sensitivity of these cells in a ligand-independent fashion. Our data thus demonstrate that a functional AR is a prerequisite for effective therapeutic response and that aberrant expression or blockade by AAT may trigger pathways leading to emergence of PC cells with therapeutic resistance phenotype. Since the mainstay of primary therapy for PC has been AAT by pharmaco-therapeutic or surgical means, this study thus provides a new frontier for revising the AAT therapeutic strategy in conjunction with radiation and/or chemotherapeutic agents.     

Effect of exogenous melatonin on ethanol-induced changes in Na(+),K(+)- and Ca(2+)-ATPase activities in rat synaptosomes

In the present study, the effects of acute ethanol (EtOH) toxicity and of exogenous melatonin (MLT) on this toxicity were examined by measuring membrane-bound ATPases and acetylcholinesterase activities in rat synaptosomal membranes. The concentrations of plasma -tocopherol and adrenal ascorbic acid (AA) were also measured. Synaptosomal Na⁺,K⁺-ATPase and Ca²⁺-ATPase activities were significantly depressed in acute EtOH-intoxicated rats compared with controls, while acetylcholinesterase activity remained unaltered. Pretreatment with MLT (10 mg/kg) prior to acute EtOH administration prevented EtOH-induced inhibition of ATPases. Adrenal AA and plasma -tocopherol levels were also depressed regardless of MLT pretreatment. MLT treatment alone affected neither membrane-bound enzyme activities nor tissue and blood levels of vitamins C and E. It is concluded that acute EtOH intoxication disturbs neural transport functions through the membrane-bound ATPase activity depression. Reduced AA and -tocopherol levels may contribute to the neurodegenerative effects of EtOH. However, pretreatment with a high dose of MLT before EtOH administration may be beneficial to prevent EtOH-induced toxicity on ATPase-mediated neural transport functions.     

A study on the structures of the substituted (aminomethyl)lithium and (thiomethyl)lithium compounds

The structures of substituted (aminomethyl)lithium and (thiomethyl)lithium compounds have been examined. Geometric parameters, charge densities, bond orders, dipole moments and heats of formation for all the members of the two series of monomers and dimers of the units LiCN(R)2 and LiCSR where R=H, CH3(Me), C6H5(Ph) have been calculated. The structures of the three complex compounds containing the same units; [[Li(CH2SMe)(THF)]X], [Li2(CH2SPh)2(THF)4] and [Li2(CH2NPh2)2(THF)3] have also been modeled. Geometry optimizations have been performed with the semiempirical PM3 method. The molecular orbital calculations have been carried out by a self-consistent field method using the restricted Hartree-Fock formalism. Comparisons have been made with the corresponding properties of methyl lithium monomer and dimer. The results show that in all of the nitrogen-containing monomers, the C-Li bonds weaken and the Li-C-H(N) angles decrease due to the coordination of lithium with nitrogen. Substitution of hydrogen atoms by methyl or phenyl groups decreases the Li-N coordination. In the sulfur-containing compounds, sulfur behaves similarly to nitrogen but the changes are smaller because the 3p lone-pair orbital of sulfur is higher in energy than the 2p lone-pair of nitrogen. All the dimers of nitrogen/sulfur-containing methyl lithium derivatives form six-membered rings in which the Li-N(S) coordination is greater than the one in the corresponding monomers. Dimerization reactions have been found to be exothermic and the formation of all the dimers is favored. The results obtained for the three complex structures are comparable to the experimental results reported in the literature.Keywords:     

Crystal Structure of the Human Cannabinoid Receptor CB2

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Effects of magnesium supplementation on blood parameters of athletes at rest and after exercise

The effects of magnesium supplementation on blood parameters were studied during a period of 4 wk in adult tae-kwon-do athletes at rest and exhaustion. Thirty healthy subjects of ages ranging in age from 18 to 22 yr were included in the study. The subjects were separated into three groups, as follows: Group 1 consisted of subjects who did not train receiving 10 mg/kg/d magnesium. Group 2 included subjects equally supplemented with magnesium and exercising 90–120 min/d for 5 d/wk. Group 3 were subject to the same exercise regime but did not receive magnesium supplements. The leukocyte count (WBC) was significantly higher in groups 1 and 2 than in the subjects who did not receive any supplements (p < 0.05). There were no significant differences in the WBC of the two groups under magnesium supplementation. The erythrocyte, hemoglobin, and trombocyte levels were significantly increased in all groups (p < 0.05), but the hematocrit levels did not show any differences between the groups although they were increased after supplementation and exercise. These results suggest that magnesium supplementation positively influences the performance of training athletes by increasing erythrocyte and hemoglobin levels.