β-keto amyrin isolated from Cryptostegia grandiflora R. br. inhibits inflammation caused by Daboia russellii viper venom: Direct binding of β-keto amyrin to phospholipase A2

The search for mechanism-based anti-inflammatory therapies is of fundamental importance to avoid undesired off-target effects. Phospholipase A2 (PLA2) activity is a potential molecular target for anti-inflammatory drugs because it fuels arachidonic acid needed to synthesize inflammation mediators, such as prostaglandins. Herein, we aim to investigate the molecular mechanism by which β-keto amyrin isolated from a methanolic extract of Cryptostegia grandiflora R. Br. Leaves can inhibit inflammation caused by Daboia russellii viper (DR) venom that mainly contains PLA2. We found that β-keto amyrin neutralizes DR venom-induced paw-edema in a mouse model. Molecular docking of PLA2 with β-keto amyrin complex resulted in a higher binding energy score of -8.86 kcal/mol and an inhibition constant of 611.7 nM. Diclofenac had a binding energy of -7.04 kcal/mol and an IC50 value of 620 nM, which predicts a poorer binding interaction than β-keto amyrin. The higher conformational stability of β-keto amyrin interaction compared to diclofenac is confirmed by molecular dynamics simulation. β-keto amyrin isolated from C. grandiflora inhibits the PLA2 activity contained in Daboia russellii viper venom. The anti-inflammatory property of β-keto amyrin is due to its direct binding into the active site of PLA2, thus inhibiting its enzyme activity.

Wheat EARLY FLOWERING 3 affects heading date without disrupting circadian oscillations

Plant breeders have indirectly selected for variation at circadian-associated loci in many of the world's major crops, when breeding to increase yield and improve crop performance. Using an eight-parent Multiparent Advanced Generation Inter-Cross (MAGIC) population, we investigated how variation in circadian clock-associated genes contributes to the regulation of heading date in UK and European winter wheat (Triticum aestivum) varieties. We identified homoeologues of EARLY FLOWERING 3 (ELF3) as candidates for the Earliness per se (Eps) D1 and B1 loci under field conditions. We then confirmed a single-nucleotide polymorphism within the coding region of TaELF3-B1 as a candidate polymorphism underlying the Eps-B1 locus. We found that a reported deletion at the Eps-D1 locus encompassing TaELF3-D1 is, instead, an allele that lies within an introgression region containing an inversion relative to the Chinese Spring D genome. Using Triticum turgidum cv. Kronos carrying loss-of-function alleles of TtELF3, we showed that ELF3 regulates heading, with loss of a single ELF3 homoeologue sufficient to alter heading date. These studies demonstrated that ELF3 forms part of the circadian oscillator; however, the loss of all homoeologues was required to affect circadian rhythms. Similarly, loss of functional LUX ARRHYTHMO (LUX) in T. aestivum, an orthologue of a protein partner of Arabidopsis (Arabidopsis thaliana) ELF3, severely disrupted circadian rhythms. ELF3 and LUX transcripts are not co-expressed at dusk, suggesting that the structure of the wheat circadian oscillator might differ from that of Arabidopsis. Our demonstration that alterations to ELF3 homoeologues can affect heading date separately from effects on the circadian oscillator suggests a role for ELF3 in cereal photoperiodic responses that could be selected for without pleiotropic deleterious alterations to circadian rhythms.

Na+ Sensitivity of the KAT2-Like Channel Is a Common Feature of Cucurbits and Depends on the S5-P-S6 Segment

Inhibition of Shaker K+ channel activity by external Na+ was previously reported in the melon (Cucumis melo L.) inwardly rectifying K+ channel MIRK and was hypothesized to contribute to salt tolerance. In this study, two inward Shaker K+ channels, CsKAT2 from cucumber (Cucumis sativus) and ClKAT2 from watermelon (Citrullus lanatus), were identified and characterized in Xenopus oocytes. Both channels were inwardly rectifying K+ channels with higher permeability to potassium than other monovalent cations and more active when external pH was acidic. Similarly to MIRK, their activity displayed an inhibition by external Na+, thus suggesting a common feature in Cucurbitaceae (Cucumis spp., Citrullus spp.). CsKAT2 and ClKAT2 are highly expressed in guard cells. After 24 h of plant treatment with 100 mM NaCl, the three KAT2-like genes were significantly downregulated in leaves and guard cells. Reciprocal chimeras were obtained between MIRK and Na+-insensitive AtKAT2 cDNAs. The chimera where the MIRK S5-P-S6 segment was replaced by that from AtKAT2 no longer showed Na+ sensitivity, while the inverse chimera gained Na+ sensitivity. These results provide evidence that the molecular basis of the channel blockage by Na+ is located in the S5-P-S6 region. Comparison of the electrostatic property in the S5-P-S6 region in AtKAT2 and MIRK revealed four key amino acid residues potentially governing Na+ sensitivity.

Chronoculture, harnessing the circadian clock to improve crop yield and sustainability

Human health is dependent on a plentiful and nutritious supply of food, primarily derived from crop plants. Rhythmic supply of light as a result of the day and night cycle led to the evolution of circadian clocks that modulate most plant physiology, photosynthesis, metabolism, and development. To regulate crop traits and adaptation, breeders have indirectly selected for variation at circadian genes. The pervasive impact of the circadian system on crops suggests that future food production might be improved by modifying circadian rhythms, engineering the timing of transgene expression, and applying agricultural treatments at the most effective time of day. We describe the applied research required to take advantage of circadian biology in agriculture to increase production and reduce inputs.

Anti-oxidant and anti-inflammatory effect of polar extracts obtained from waste product of wine making

A lot of diseases are characterized by an increased inflammatory response with an exacerbated production of free radicals. The anti-inflammatory effect of different compounds with antioxidant capacity, as polyphenols present in grape is well known. Therefore, the objective is to evaluate the anti-oxidant and anti-inflammatory activity of waste product of wine production.Six different non-toxic-marc-polar extracts from Malbec and Syrah grape varieties were obtained, their total phenol and flavonoid content were evaluated, and their antioxidant and anti-inflammatory activity were determined.High content of total phenols and flavonoids were found mainly in extracts obtained from Syrah (80.51 ± 16.63 g equivalent to gallic acid/100 g and 25.47 ± 3.33 g equivalent to quercetin/100 g). In addition, they had a high antioxidant effect (above 88.5% of ABTS inhibition by Syrah extracts). Finally, all extracts decreased the nitric oxide (NO) production, but this was more accented when extract from Syrah obtained by infusion was used, which decreased NO levels to baseline (4.46 µM).Taking together, our results show the potential pharmaceutical use of waste product of wine making to prevent or to treat diseases which inflammatory response is exacerbated.

A chronic high-fat diet causes sperm head alterations in C57BL/6J mice

A chronic-positive energetic balance has been directly correlated with infertility in men, but the involved mechanisms remain unknown. Herein we investigated weather in a mouse model a chronic feeding with a diet supplemented with chicken fat affects sperm head morphology. To accomplish this, we fed mice for 16 weeks with either control food (low-fat diet, LFD) or control food supplemented with 22% chicken fat (high-fat diet, HFD). At the end of the feeding regimen, we measured: redox and inflammatory changes, cholesterol accumulation in testis and analyzed testicular morphological structure and ultra-structure and liver morphology. We found that the mice fed HFD resembled some features of the human metabolic syndrome, including systemic oxidative stress and inflammation, this group showed an increment in the following parameters; central adiposity (adiposity index: 1.07 ± 0.10 vs 2.26 ± 0.17), dyslipidemia (total cholesterol: 153.3 ± 2.6 vs 175.1 ± 8.08 mg/dL), insulin resistance (indirect Insulin resistance index, TG/HDL-c: 2.94 ± 0.33 vs 3.68 ± 0.15) and fatty liver. Increased cholesterol content measured by filipin was found in the testicles from HFD (fluorescence intensity increase to 50%), as well as an alteration of spermiogenesis. Most remarkably, a disorganized manchette-perinuclear ring complex and an altered morphology of the sperm head were observed in the spermatozoa of HFD-fed mice. These results add new information to our understanding about the mechanisms by which systemic oxidative stress and inflammation may influence sperm-head morphology and indirectly male fertility.

The nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide dampens lipopolysaccharide-induced transcriptomic changes in macrophages

OBJECTIVE

M1-like inflammatory phenotype of macrophages plays a critical role in tissue damage in chronic inflammatory diseases. Previously, we found that the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) dampens lipopolysaccharide (LPS)-triggered inflammatory priming of RAW 264.7 cells. Herein, we tested whether DMPO by itself can induce changes in macrophage transcriptome, and that these effects may prevent LPS-induced activation of macrophages.

MATERIALS AND METHODS

To test our hypothesis, we performed a transcriptomic and bioinformatics analysis in RAW 264.7 cells incubated with or without LPS, in the presence or in the absence of DMPO.

RESULTS

Functional data analysis showed 79 differentially expressed genes (DEGs) when comparing DMPO vs Control. We used DAVID databases for identifying enriched gene ontology terms and Ingenuity Pathway Analysis for functional analysis. Our data showed that DMPO vs Control comparison of DEGs is related to downregulation immune-system processes among others. Functional analysis indicated that interferon-response factor 7 and toll-like receptor were related (predicted inhibitions) to the observed transcriptomic effects of DMPO. Functional data analyses of the DMPO + LPS vs LPS DEGs were consistent with DMPO-dampening LPS-induced inflammatory transcriptomic profile in RAW 264.7. These changes were confirmed using Nanostring technology.

CONCLUSIONS

Taking together our data, surprisingly, indicate that DMPO by itself affects gene expression related to regulation of immune system and that DMPO dampens LPS-triggered MyD88- and TRIF-dependent signaling pathways. Our research provides critical data for further studies on the possible use of DMPO as a structural platform for the design of novel mechanism-based anti-inflammatory drugs.

Modulation of arachidonic acid turnover in macrophages by cadmium

The effects of cadmium (Cd) induced redox changes on arachidonic acid (AA) turnover in mouse resident peritoneal macrophages (pM) were studied. The pre-incubation of pM in a medium containing glutathione (GSH, 0.1 or 1 mM) for 6 h protects pM from loss of viability and AA uptake diminution induced by Cd with regard to non pre-incubated cultures. The exposure of macrophages to Cd 10 microM decreases AA uptake within 2 h and increases AA release in relation to non-exposed macrophages. It also enhances AA mobilization and reactive oxygen species (ROS) release induced by okadaic acid and opsonized zimosan and decreases those induced by lipopolysaccharide, but does not modify either AA mobilization or ROS release induced by phorbol ester. These results might suggest that redox changes induced by Cd produce an important impact on AA turnover in macrophages; information that is relevant in the understanding of the cellular toxicity of this metal.

Varied protocols of cadmium exposure produce different effects on nitric oxide production in macrophages

Different protocols of cadmium (Cd) exposure in non-cytotoxic conditions (i.e. 10 microM Cd for 18 h), and their effect on nitric oxide (NO) generation induced by NO inductor agents (NOIA) in peritoneal macrophages (pM) were studied. In all cases, NOIA (i.e. bacterial lipopolysaccharide [LPS], phorbol ester [PMA], okadaic acid [OA] or their combinations [LPS/OA] and [LPS/PMA]) were added at the beginning of the first incubation, only. Simultaneously exposure with 10 microM Cd enhanced NO generation and inducible NO synthase (iNOS) expression evoked by LPS, OA, PMA; those induced by LPS/PMA were not modified; and those caused by LPS/OA in relation to culture without Cd (medium) decreased. Double incubation, either with or without Cd (Cd+Cd or medium+medium), or Cd added at the start of the first or second incubation only (Cd+medium or medium+Cd), were tested. After the second incubation, medium+Cd protocol produced the highest NO generation in relation to other exposure protocols. When NO production was measured at the end of the second incubation, Cd+medium protocol enhanced NO production induced by OA, and LPS/OA, while medium+Cd protocol enhanced the response to LPS, PMA, and LPS/OA, in both cases in relation to the first incubation. Cd+Cd incubation protocol decreases the response to all NOIA in relation to another protocols. Cd effect on NO generation in macrophages is dependent on protocol and timing of exposure.

Biphasic effect of cadmium in non-cytotoxic conditions on the secretion of nitric oxide from peritoneal macrophages

The effects of cadmium (Cd) in non-cytotoxic conditions on the nitric oxide (NO) production in peritoneal macrophages (pM) were studied. Peritoneal macrophages from Balb/c mice were incubated over 18 h with 5, 10, 20, or 25 microM Cd2+ (as CdCl2 21:2 H2O) in the culture medium. Concentrations of 20 microM Cd2+ and over had cytotoxic effects, measured by MTT assay. Cell viability with 10 microM Cd2+ in the medium was above 90% after 18 h of incubation, and above 80% after 72 h. At this same Cd2+ concentration, NO production increased from 6 to 18 h. At 24 h production decreased but was still above control levels. At 48 h production NO was near control levels, and continued to decrease until the end of the experiment (72 h). NO levels produced with Cd2+ concentrations of 5, 10 and 20 microM in the medium were above the control at 18 h. NO production and lipoperoxidation increased simultaneously after 18 h with 10 microM of Cd in the medium. Amounts of inducible nitric oxide synthase (iNOS) protein and iNOS activity also increased. At a concentration of 10 microM Cd has a biphasic effect on NO production over time.