Sex- and lineage-specific inheritance of depression-like behavior in the rat

The Wistar–Kyoto (WKY) rat exhibits physiological and behavioral similarities to endophenotypes of human depression. In the forced swim test (FST), a well-characterized antidepressant-reversible test for behavioral despair in rodents, WKYs express characteristics of behavioral despair; increased immobility, and decreased climbing. To map genetic loci linked to behavior in the FST, we conducted a quantitative trait loci (QTL) analysis of the segregating F2 generation of a WKY × Fisher 344 (F344) reciprocal intercross. Using linear-model-based genome scans to include covariate (sex or lineage)-by-QTL interaction effects, four significant QTL influencing climbing behavior were identified. In addition, we identified three, seven, and two suggestive QTL for climbing, immobility, and swimming, respectively. One of these loci was pleiotropic, affecting both immobility and climbing. As found in human linkage studies, several of these QTL showed sex- and/or lineage-dependent effects. A simultaneous search strategy identified three epistatic locus pairs for climbing. Multiple regression analysis was employed to characterize the joint contributions of these QTL and to clarify the sex- and lineage-dependent effects. As expected for complex traits, FST behavior is influenced by multiple QTL of small effect, each contributing 5%–10%, accounting for a total 10%–30% of the phenotypic variance. A number of loci mapped in this study share overlapping candidate regions with previously identified emotionality QTL in mice as well as with susceptibility loci recognized by linkage or genome scan analyses for major depression or bipolar disorder in humans. The presence of these loci across species suggests that these QTL may represent universal genetic factors contributing to mood disorders.     

Nutritional Energy Stimulates NAD+ Production to Promote Tankyrase-Mediated PARsylation in Insulinoma Cells

The poly-ADP-ribosylation (PARsylation) activity of tankyrase (TNKS) regulates diverse physiological processes including energy metabolism and wnt/β-catenin signaling. This TNKS activity uses NAD⁺ as a co-substrate to post-translationally modify various acceptor proteins including TNKS itself. PARsylation by TNKS often tags the acceptors for ubiquitination and proteasomal degradation. Whether this TNKS activity is regulated by physiological changes in NAD⁺ levels or, more broadly, in cellular energy charge has not been investigated. Because the NAD⁺ biosynthetic enzyme nicotinamide phosphoribosyltransferase (NAMPT) in vitro is robustly potentiated by ATP, we hypothesized that nutritional energy might stimulate cellular NAMPT to produce NAD⁺ and thereby augment TNKS catalysis. Using insulin-secreting cells as a model, we showed that glucose indeed stimulates the autoPARsylation of TNKS and consequently its turnover by the ubiquitin-proteasomal system. This glucose effect on TNKS is mediated primarily by NAD⁺ since it is mirrored by the NAD⁺ precursor nicotinamide mononucleotide (NMN), and is blunted by the NAMPT inhibitor FK866. The TNKS-destabilizing effect of glucose is shared by other metabolic fuels including pyruvate and amino acids. NAD⁺ flux analysis showed that glucose and nutrients, by increasing ATP, stimulate NAMPT-mediated NAD⁺ production to expand NAD⁺ stores. Collectively our data uncover a metabolic pathway whereby nutritional energy augments NAD⁺ production to drive the PARsylating activity of TNKS, leading to autoPARsylation-dependent degradation of the TNKS protein. The modulation of TNKS catalytic activity and protein abundance by cellular energy charge could potentially impose a nutritional control on the many processes that TNKS regulates through PARsylation. More broadly, the stimulation of NAD⁺ production by ATP suggests that nutritional energy may enhance the functions of other NAD⁺-driven enzymes including sirtuins.     

Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels

Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles.     

Effect of the petite mutation on maltose and alpha-methylgucoside fermentation inSaccharomyces cerevisiae.

Summary Several hundred petite mutants were isolated from yeast strains of different genotype to examine the effect of the petite mutation on maltose and alpha-methylglucoside fermentation. In most cases petite mutants isolated retain the ability to ferment maltose and alpha-methylglucoside, although at a slower rate. In one strain (1403-7A), however, the ability to ferment alpha-methylglucoside is completely lost in all petite mutants isolated from this strain. It is suggested that mitochondrial factors may be involved in the utilization of alpha-methylglucoside in strain 1403-7A.     

Caffeine enhancement of radiation killing in different strains of Saccharomyces cerevisiae.

Summary Haploid and diploid wild type strains, and three classes of radiation-sensitive mutants of Saccharomyces cerevisiae were tested for enhancement of UV-inactivation by caffeine in growth medium. In addition, the sensitizing effect of caffeine was studied in a haploid and a diploid wild type strain after gamma-irradiation. The drug sensitized the UV-irradiated cells of all strains except those reported to be only slightly UV-sensitive but highly sensitive to ionizing radiation. After gamma-irradiation, no caffeine-enhancement of killing was observed in stationary phase cells of either the haploid or the diploid strain. However, log-phase cells of both strains were partially sensitized.The results of both sets of experiments suggested that caffeine interferes with a recombinational repair occurring in cells in S or G2 phase.     

Differential type I IFN-inducing abilities of wild-type versus vaccine strains of measles virus

Laboratory adapted and vaccine strains of measles virus (MV) induced type I IFN in infected cells. The wild-type strains in contrast induced it to a far lesser extent. We have investigated the mechanism for this differential type I IFN induction in monocyte-derived dendritic cells infected with representative MV strains. Laboratory adapted strains Nagahata and Edmonston infected monocyte-derived dendritic cells and activated IRF-3 followed by IFN-beta production, while wild-type MS failed to activate IRF-3. The viral IRF-3 activation is induced within 2 h, an early response occurring before protein synthesis. Receptor usage of CD46 or CD150 and nucleocapsid (N) protein variations barely affected the strain-to-strain difference in IFN-inducing abilities. Strikingly, most of the IFN-inducing strains possessed defective interference (DI) RNAs of varying sizes. In addition, an artificially produced DI RNA consisting of stem (the leader and trailer of MV) and loop (the GFP sequence) exhibited potential IFN-inducing ability. In this case, however, cytoplasmic introduction was needed for DI RNA to induce type I IFN in target cells. By gene-silencing analysis, DI RNA activated the RIG-I/MDA5-mitochondria antiviral signaling pathway, but not the TLR3-TICAM-1 pathway. DI RNA-containing strains induced IFN-beta mRNA within 2 h while the same recombinant strains with no DI RNA required >12 h postinfection to attain similar levels of IFN-beta mRNA. Thus, the stem-loop structure, rather than full genome replication or specific internal sequences of the MV genome, is required for an early phase of type I IFN induction by MV in host cells.     

Follicular waves during the oestrous cycle in Nili-Ravi buffaloes undergoing spontaneous and PGF2alpha-induced luteolysis

The objective of this study was to characterize the follicular waves and associated ovarian events during spontaneous and PGF(2alpha)-induced oestrous cycles in Nili-Ravi buffaloes. In Exp. 1, (n=13 oestrous cycles) follicular and luteal development was monitored by ultrasonography and jugular blood samples were collected simultaneously on alternate days. Of 12 oestrous cycles, 9 (75%) had two waves of follicular activity and only 3 (25%) had three waves. The mean (+/-S.E.M.) length of the oestrous cycle was shorter (P<0.05) in buffaloes with two waves than in those with three waves (21.2+/-0.1 days versus 22.8+/-0.1 days). In Exp. 2, follicular dynamics were compared in buffaloes undergoing spontaneous (n=12 oestrous cycles) and PGF(2alpha)-induced (n=9) regression of the corpus luteum (CL). The dynamics of ovulatory follicular growth during the 3 days before oestrus were similar (P>0.05) in buffaloes undergoing spontaneous and PGF(2alpha)-induced luteolysis. These results show that (1) the majority of buffaloes had a two wave pattern of follicular growth and emergence of a third wave was associated with a longer luteal phase, and (2) follicular dynamics during the 3 days before oestrus were similar in buffaloes undergoing spontaneous and PGF(2alpha)-induced luteolysis.     

Gene therapy with an improved doxycycline-regulated plasmid encoding a tumour necrosis factor-alpha inhibitor in experimental arthritis

Inhibition of tumour necrosis factor (TNF)-alpha with biological molecules has proven an effective treatment for rheumatoid arthritis, achieving a 20% improvement in American College of Rheumatology score in up to 65% of patients. The main drawback to these and many other biological treatments has been their expense, which has precluded their widespread application. Biological molecules could alternatively be delivered by gene therapy as the encoding DNA. We have developed novel plasmid vectors termed pGTLMIK and pGTTMIK, from which luciferase and a dimeric TNF receptor II (dTNFR) are respectively expressed in a doxycycline (Dox)-regulated manner. Regulated expression of luciferase from the self-contained plasmid pGTLMIK was examined in vitro in a variety of cell lines and in vivo following intramuscular delivery with electroporation in DBA/1 mice. Dox-regulated expression of luciferase from pGTLMIK of approximately 1,000-fold was demonstrated in vitro, and efficient regulation was observed in vivo. The vector pGTTMIK encoding dTNFR was delivered by the same route with and without administration of Dox to mice with collagen-induced arthritis. When pGTTMIK was delivered after the onset of arthritis, progression of the disease in terms of both paw thickness and clinical score was inhibited when Dox was also administered. Vectors with similar regulation characteristics may be suitable for clinical application.     

The HHEX rs1111875A/G gene polymorphism is associated with susceptibility to type 2 diabetes in the iranian population

The illuminating picture of genetic mechanisms underlying the development of type 2 diabetes (T2DM) includes differently accumulated genetic polymorphisms that increase the risk along with environmental factors. A number of single nucleotide polymorphisms (SNPs) are indicated to be linked with T2DM, but also conflicting results have been found. To examine the contribution of these polymorphisms in conferring susceptibility to T2DM, the association of HHEX rs1111875A/G and CDKN2A/B rs10811661C/T common gene polymorphisms with the risk of T2DM in an Iranian population was evaluated. In this study participated 140 patients and 140 controls. Genomic DNA was extracted from samples and genotyping of the polymorphisms was performed by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique. A significant association was found with the G allele (OR = 1.729, CI = 1.184–2.523, P = 0.004) and GG genotype (OR = 2.921, 95% CI = 1.789–4.771, P< 0.001) of the rs1111875A/G SNP for susceptibility to T2DM in the recessive model. Furthermore, compared with the GG genotype, individuals with the GA genotype had a lower risk to develop T2DM (OR = 0.237, 95% CI = 0.137–0.408, P< 0.001) in the additive model. In addition, an association between the polymorphism and BMI in regard to the risk of T2DM was identified. The genotype and allele frequencies of the rs10811661C/T polymorphism did not show a statistically significant association with T2DM in any genetic model. Our results show that the rs1111875A/G polymorphism is an important susceptibility polymorphism for the development of T2DM in the Iranian population. Also, these findings support that this polymorphism is a key genetic risk factor for the development of T2DM in multiple ethnic populations.