HSP70 expression in the CNS in response to exercise and heat stress in rats

We havepreviously documented the regional distribution of 70-kDa heat shockprotein (HSP70) in brains of rats made hyperthermic by brief exposureto high-powered microwaves (HPM; 2.06 GHz). We now compare HSP70expression induced by HPM exposure to that induced by exertionaland/or environmental heat stress. Rats were chronicallyimplanted with a temperature probe guide in the hypothalamic region ofthe brain (T_br). After recovery,the following treatment groups were examined: HPM; sham exposed;treadmill exercise at room temperature (24°C; Ex-1); treadmillexercise in a warm environment (34°C; Ex-2); and sedentary groups(Sed-1 and Sed-2), in which ambient temperature was adjusted so thatthe T_br mimicked the T_br in the corresponding exercisegroups. Significant HSP70 expression occurred only in the hyperthermic(Ex-2, Sed-2, and HPM) groups. The pattern of HSP70 expression wassimilar among Ex-2 and Sed-2 rats but differed from that in HPM rats.We conclude that 1) the pattern ofHSP70 expression differs between HPM and nonmicrowave heating, and2) exercise alone was not sufficientto induce central HSP70 expression.

     

RNA stem–loop enhanced expression of previously non-expressible genes

The key step in bacterial translation is formation of the pre-initiation complex. This requires initial contacts between mRNA, fMet-tRNA and the 30S subunit of the ribosome, steps that limit the initiation of translation. Here we report a method for improving translational initiation, which allows expression of several previously non-expressible genes. This method has potential applications in heterologous protein synthesis and high-throughput expression systems. We introduced a synthetic RNA stem–loop (stem length, 7 bp; ΔG₀ = –9.9 kcal/mol) in front of various gene sequences. In each case, the stem–loop was inserted 15 nt downstream from the start codon. Insertion of the stem–loop allowed in vitro expression of five previously non-expressible genes and enhanced the expression of all other genes investigated. Analysis of the RNA structure proved that the stem–loop was formed in vitro, and demonstrated that stabilization of the ribosome binding site is due to stem–loop introduction. By theoretical RNA structure analysis we showed that the inserted RNA stem–loop suppresses long-range interactions between the translation initiation domain and gene-specific mRNA sequences. Thus the inserted RNA stem–loop supports the formation of a separate translational initiation domain, which is more accessible to ribosome binding.     

Decreased cerebral Irp‐1B limits impact of social isolation in wild type and Alzheimer's disease modeled in Drosophila melanogaster

Environmental factors, such as housing conditions and cognitively stimulating activities, have been shown to affect behavioral phenotypes and to modulate neurodegenerative conditions such as Alzheimer's disease (AD). AD is a progressive neurodegenerative disorder affecting cognitive functions. Epidemiological evidence and experimental studies using rodent models have indicated that social interaction reduces development and progression of disease. Drosophila models of Aβ42‐associated AD lead to AD‐like phenotypes, such as long‐term memory impairment, locomotor and survival deficits, while effects of environmental conditions on AD‐associated phenotypes have not been assessed in the fly. Here, we show that single housing reduced survival and motor performance of Aβ42 expressing and control flies. Gene expression analyses of Aβ42 expressing and control flies that had been exposed to different housing conditions showed upregulation of Iron regulatory protein 1B (Irp‐1B) in fly brains following single housing. Downregulating Irp‐1B in neurons of single‐housed Aβ42 expressing and control flies rescued both survival and motor performance deficits. Thus, we provide novel evidence that increased cerebral expression of Irp‐1B may underlie worsened behavioral outcome in socially deprived flies and can additionally modulate AD‐like phenotypes.     

Conditioned mesenchymal stem cells attenuate progression of chronic kidney disease through inhibition of epithelial‐to‐mesenchymal transition and immune modulation

Mesenchymal stem cells (MSCs) have been shown to improve the outcome of acute renal injury models; but whether MSCs can delay renal failure in chronic kidney disease (CKD) remains unclear. In the present study, the were cultured in media containing various concentrations of basic fibroblast growth factor, epidermal growth factor and ascorbic acid 2‐phosphate to investigate whether hepatocyte growth factor (HGF) secretion could be increased by the stimulation of these growth factors. Then, TGF‐β1‐treated renal interstitial fibroblast (NRK‐49F), renal proximal tubular cells (NRK‐52E) and podocytes were co‐cultured with conditioned MSCs in the absence or presence of ascorbic acid 2‐phosphate to quantify the protective effects of conditioned MSCs on renal cells. Moreover, male Sprague‐Dawley rats were treated with 1 × 10⁶ conditioned MSCs immediately after 5/6 nephrectomy and every other week through the tail vein for 14 weeks. It was found that basic fibroblast growth factor, epidermal growth factor and ascorbic acid 2‐phosphate promoted HGF secretion in MSCs. Besides, conditioned MSCs were found to be protective against TGF‐β1 induced epithelial‐to‐mesenchymal transition of NRK‐52E and activation of NRK‐49F cells. Furthermore, conditioned MSCs protected podocytes from TGF‐β1‐induced loss of synaptopodin, fibronectin induction, cell death and apoptosis. Rats transplanted with conditioned human MSCs had a significantly increase in creatinine clearance rate, decrease in glomerulosclerosis, interstitial fibrosis and increase in CD4⁺CD25⁺Foxp3⁺ regulatory T cells counts in splenocytes. Together, our studies indicated that conditioned MSCs preserve renal function by their anti‐fibrotic and anti‐inflammatory effects. Transplantation of conditioned MSCs may be useful in treating CKD.     

The chemical compound ‘Heatin’ stimulates hypocotyl elongation and interferes with the Arabidopsis NIT1-subfamily of nitrilases

Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2–deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound ‘Heatin’, containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.     

A preliminary diagnosis and recommendation integrated system (DRIS) model for diagnosing the nutrient status of sweet potato (Ipomoea batatas)

Critical leaf nutrient concentrations have often been used to diagnose the nutritional causes of crop underperformance. Unfortunately, these diagnostic criteria are not available for mature, tuber-bearing sweet potato plants (the word ‘tuber’ being used to describe a swollen root rather than a swollen stem). The Diagnosis and Recommendation Integrated System (DRIS), however, provides a reliable means of linking leaf nutrient concentrations to the yield of sweet potato tubers, and may be developed for this crop using existing data from regional crop surveys. In the present study, tuber yield and leaf nutrient concentration data from a survey of sweet potato gardens conducted in the Papua New Guinea (PNG) highlands in 2005 were used to establish DRIS N, P, K, and S norms and statistical parameters for sweet potato. Although the database was relatively small, the norms derived for nutrient ratios of key biological significance, i.e. N/S and K/N, were within the expected narrow ranges for higher plants, giving credibility to both the database and the DRIS model. Data from future surveys and field trials may subsequently be used to enlarge the database allowing the refinement of model parameters and hopefully an expansion of diagnostic scope to include other macro and micro-nutrients. As it stands, though, this preliminary DRIS model for sweet potato is possibly the best diagnostic tool currently available for evaluating the N, P, K and S statuses of sweet potato crops in the pacific region.     

The Larval Eye of Nannochoristid Scorpionflies (Insecta,Mecoptera)

Abstract The stemmata of last–instar Nannochoristalarvae are compound eyes composed of 10 or more ommatidia. Each ommatidium has four Semper cells, four distal and four proximal retinula cells which form a cruciform and layered rhabdom. The ommatidia are separated by epidermal cells (possibly rudimentary pigment cells). Corneal lenses are lacking. At the posterior edge, aberrant stemma units may be present which lack a dioptric apparatus and have a star–shaped rhabdom composed of at least six retinula cells. The stemmata of Nannochoristaappear to be derived from stemmata of the Panorpa-type (Mecoptera-Panorpidae). Differences between the stemmata of Nannochoristaand Panorpacan be explained as adaptations to aquatic life (flat cornea) or as regression. A compound larval eye is ascribed to the ground plan of the Mecoptera sensu latoand is considered a genuine plesiomorphy. The identical basic number (seven) of stemmata in the Neuropteroid/Coleoptera assemblage, Amphiesmenoptera and some Mecoptera (Bittacidae, Boreidae) is attributed to parallel evolution.     

Anti-Proliferative Effects of Evodiamine on Human Breast Cancer Cells

Endocrine sensitivity, assessed by the expression of estrogen receptor (ER), has long been the predict factor to guide therapeutic decisions. Tamoxifen has been the most successful hormonal treatment in endocrine-sensitive breast cancer. However, in estrogen-insensitive cancer tamoxifen showed less effectiveness than in estrogen-sensitive cancer. It is interesting to develop new drugs against both hormone-sensitive and insensitive tumor. In this present study we examined anticancer effects of evodiamine extracted from the Chinese herb, Evodiae fructus, in estrogen-dependent and –independent human breast cancer cells, MCF-7 and MDA-MB-231 cells, respectively. Evodiamine inhibited the proliferation of MCF-7 and MDA-MB-231 cells in a concentration-dependent manner with concentration of 1×10⁻⁶ and 1×10⁻⁵ M. Evodiamine also induced apoptosis via up-regulation of caspase 7 activation, PARP cleavage (Bik and Bax expression). The expression of ER α and β in protein and mRNA levels was down-regulated by evodiamine according to data from immunoblotting and RT-PCR analysis. Overall, our results indicate that evodiamine mediates degradation of ER and induces caspase-dependent pathway leading to inhibit proliferation of breast cancer cell lines. It suggests that evodiamine may in part mediate through ER-inhibitory pathway to inhibit breast cancer cell proliferation.     

Exercise during pregnancy mitigates Alzheimer-like pathology in mouse offspring

Physical activity protects brain function in healthy individuals and those with Alzheimer's disease (AD). Evidence for beneficial effects of parental exercise on the health status of their progeny is sparse and limited to nondiseased individuals. Here, we questioned whether maternal running interferes with offspring's AD-like pathology and sought to decipher the underlying mechanisms in TgCRND8 mice. Maternal stimulation was provided by voluntary wheel running vs. standard housing during pregnancy. Following 5 mo of standard housing of transgenic and wild-type offspring, their brains were examined for AD-related pathology and/or plasticity changes. Running during pregnancy reduced β-amyloid (Aβ) plaque burden (-35%, P=0.017) and amyloidogenic APP processing in transgenic offspring and further improved the neurovascular function by orchestrating different Aβ transporters and increasing angiogenesis (+29%, P=0.022). This effect was accompanied by diminished inflammation, as indicated by reduced microgliosis (-20%, P=0.002) and down-regulation of other proinflammatory mediators, and resulted in less oxidative stress, as nitrotyrosine levels declined (-28%, P=0.029). Moreover, plasticity changes (in terms of up-regulation of reelin, synaptophysin, and ARC) were found not only in transgenic but also in wild-type offspring. We conclude that exercise during pregnancy provides long-lasting protection from neurodegeneration and improves brain plasticity in the otherwise unstimulated progeny.