Acid Signaling Molecules Research Articles

Effects of hormones on the growth and metabolite production of Amphidinium carterae under carbon sufficient and carbon limited conditions

The dinoflagellate Amphidinium carterae produces valuable fatty acids, pigments, and bioactive polyketides (e.g., amphidinols). Despite recent advances in its intensive cultivation, challenges remain that justify further work. This study explored the effects of phytohormone supplementation on growth and metabolism using a One Strain Many Compounds (OSMAC) approach. Auxins, cytokinins, jasmonates, amines, abscisic acid, gibberellic acid, and other signaling molecules were screened in batch cultures. Synthetic auxin 2-naphthoxyacetic acid (BNOA) at a final concentration of 14.84 μM (3 mg/L) emerged as the most stimulant. On a small scale, BNOA increased biomass productivity by up to 32 % and hemolytic activity in terms of productivity by 50 %. Scaling up in 10 L bubble column photobioreactor cultures with the addition of BNOA, but without CO2 supplementation, resulted in levels of amphidinol production comparable to those achieved with CO2 addition. Compared to the control without BNOA, BNOA cultures generated 2.2-fold more biomass during the stationary growth phase, and amphidinol production increased fourfold per unit of biomass. This work reveals that the addition of exogenous phytohormones such as BNOA can sustain the production of valuable metabolites in A. carterae, eliminating the need for additional CO2 and its associated costs. This promising approach highlights the potential of hormone supplementation as a cost-effective and efficient cultivation strategy for dinoflagellate bioprocesses.

Novel insights on biofilm development in sewers: Cross-kingdom exchange of quorum-sensing signaling molecules

In sewers, biofilms are generated due to long-distance sewage transportation. However, the metabolism and reproduction of bacteria and fungi in biofilms and the mechanism of cross-kingdom exchanges mediated by quorum-sensing signaling molecules remain unclear. In this study, the distributions of bacteria and fungi communities in biofilms were investigated using high-throughput sequencing. The mechanism by which signaling molecules participate in biofilm development was explored through statistical analysis. The ecosystem operation mode featured by pollutant conversion, bacteria–fungi interaction (BFI), and cross-kingdom exchange of key signaling molecules in municipal sewers was clarified. The result showed that variations in C, N, and S pollutants in the sewer were related to BFI. Lactivibrio and Candida, key species generating signaling molecules in bacteria and fungi, significantly accelerated pollutant biodegradation and biofilm development. Additionally, a quantitative detection system was established for the signaling molecules. The average concentrations of C4-HSL, C10-HSL, and 3-oxo-C12-HSL (bacteria) were 0.25, 1.41, and 0.98 μg/L, respectively. Average concentrations of farnesol, tyrosol, and farnesoic acid signaling molecules were 10.04, 126.29, and 94.79 ng/L, respectively. Moreover, thickness and extracellular polymeric substances in different stages of biofilm development were explored. The results showed that acyl homoserine lactones dominated biofilm development, whereas signaling molecules of C. albicans had limited influences. The interaction of Pseudomonas aeruginosa and C. albicans dominated the cross-kingdom exchange between bacteria and fungi mediated by signaling molecules. This study reveals the characteristics of the interaction and metabolism of bacteria and fungi in sewers. It also provides theoretical references for social behaviors and the regulation of microbes in biofilms in sewers.

Analysis of homodimer formation in 12-oxophytodienoate reductase 3 in solutio and crystallo challenges the physiological role of the dimer

12-oxophytodienoate reductase 3 (OPR3) is a key enzyme in the biosynthesis of jasmonoyl-L-isoleucine, the receptor-active form of jasmonic acid and crucial signaling molecule in plant defense. OPR3 was initially crystallized as a self-inhibitory dimer, implying that homodimerization regulates enzymatic activity in response to biotic and abiotic stresses. Since a sulfate ion is bound to Y364, mimicking a phosphorylated tyrosine, it was suggested that dimer formation might be controlled by reversible phosphorylation of Y364 in vivo. To investigate OPR3 homodimerization and its potential physiological role in more detail, we performed analytical gel filtration and dynamic light scattering on wild-type OPR3 and three variants (R283D, R283E, and Y364P). The experiments revealed a rapid and highly sensitive monomer–dimer equilibrium for all OPR3 constructs. We crystallized all constructs with and without sulfate to examine its effect on the dimerization process and whether reversible phosphorylation of Y364 triggers homodimerization in vivo. All OPR3 constructs crystallized in their monomeric and dimeric forms independent of the presence of sulfate. Even variant Y364P, lacking the putative phosphorylation site, was crystallized as a self-inhibitory homodimer, indicating that Y364 is not required for dimerization. Generally, the homodimer is relatively weak, and our results raise doubts about its physiological role in regulating jasmonate biosynthesis.

The role of strigolactones in resistance to environmental stress in plants.

Abiotic stress impairs plant growth and development, thereby causing low yield and inferior quality of crops. Increasing studies reported that strigolactones (SL) are plant hormones that enhance plant stress resistance by regulating plant physiological processes and gene expressions. In this review, we introduce the response and regulatory role of SL in salt, drought, light, heat, cold and cadmium stresses in plants. This review also discusses how SL alleviate the damage of abiotic stress in plants, furthermore, introducing the mechanisms of SL enhancing plant stress resistance at the genetic level. Under abiotic stress, the exogenous SL analog GR24 can induce the biosynthesis of SL in plants, and endogenous SL can alleviate the damage caused by abiotic stress. SL enhanced the stress resistance of plants by protecting photosynthesis, enhancing the antioxidant capacity of plants and promoting the symbiosis between plants and arbuscular mycorrhiza (AM). SL interact with abscisic acid (ABA), salicylic acid (SA), auxin, cytokinin (CK), jasmonic acid (JA), hydrogen peroxide (H2O2) and other signal molecules to jointly regulate plant stress resistance. Lastly, both the importance of SL and their challenges for future work are outlined in order to further elucidate the specific mechanisms underlying the roles of SL in plant responses to abiotic stress.

Microalgae as next generation plant growth additives: Functions, applications, challenges and circular bioeconomy based solutions.

Sustainable agriculture practices involve the application of environment-friendly plant growth promoters and additives that do not negatively impact the health of the ecosystem. Stringent regulatory frameworks restricting the use of synthetic agrochemicals and the increase in demand for organically grown crops have paved the way for the development of novel bio-based plant growth promoters. In this context, microalgae biomass and derived agrochemicals offer novel sources of plant growth promotors that enhance crop productivity and impart disease resistance. These beneficial effects could be attributed to the presence of wide range of biomolecules such as soluble amino acid (AA), micronutrients, polysaccharides, phytohormones and other signaling molecules in microalgae biomass. In addition, their phototrophic nature, high photosynthetic efficiency, and wide environmental adaptability make them an attractive source of biostimulants, biofertilizers and biopesticides. The present review aims to describe the various plant growth promoting metabolites produced by microalgae and their effects on plant growth and productivity. Further, the effects elicited by microalgae biostimulants with respect to different modes of applications such as seed treatments, foliar spray and soil/root drenching is reviewed in detail. In addition, the ability of microalgae metabolites to impart tolerance against various abiotic and biotic stressors along with the mechanism of action is discussed in this paper. Although the use of microalgae based biofertilizers and biostimulants is gaining popularity, the high nutrient and water requirements and energy intensive downstream processes makes microalgae based technology commercially unsustainable. Addressing this challenge, we propose a circular economy model of microalgae mediated bioremediation coupled with biorefinery approaches of generating high value metabolites along with biofertilizer applications. We discuss and review new trends in enhancing the sustainability of microalgae biomass production by co-cultivation of algae with hydroponics and utilization of agriculture effluents.

Epoxyeicosatrienoic acids and soluble epoxide hydrolase in physiology and diseases of the central nervous system.

Epoxyeicosatrienoic acids (EETs) are fatty acid signaling molecules synthesized by cytochrome P450 epoxygenases from arachidonic acid. The biological activity of EETs is terminated when being metabolized by soluble epoxide hydrolase (sEH), a process that serves as a key regulator of tissue EETs levels. EETs act through several signaling pathways to mediate various beneficial effects, including anti-inflammation, anti-apoptosis, and anti-oxidation with relieve of endoplasmic reticulum stress, thereby sEH has become a potential therapeutic target in cardiovascular disease and cancer therapy. Enzymes for EET biosynthesis and metabolism are both widely detected in both neuron and glial cells in the central nervous system (CNS). Recent studies discovered that astrocyte-derived EETs not only mediate neurovascular coupling and neuronal excitability by maintaining glutamate homeostasis but also glia-dependent neuroprotection. Genetic ablation as well as pharmacologic inhibition of sEH has greatly helped to elucidate the physiologic actions of EETs, and maintaining or elevating brain EETs level has been demonstrated beneficial effects in CNS disease models. Here, we review the literature regarding the studies on the bioactivity of EETs and their metabolic enzyme sEH with special attention paid to their action mechanisms in the CNS, including their modulation of neuronal activity, attenuation of neuroinflammation, regulation of cerebral blood flow, and improvement of neuronal and glial cells survival. We further reviewed the recent advance on the potential application of sEH inhibition for treating cerebrovascular disease, epilepsy, and pain disorder.

Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2.

Quorum sensing (QS) is a microbial cell–cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.

Effects of ophiopogonin D on fatty acid metabolic enzymes in cardiomyocytes

To explore the effect of ophiopogonin D on main fatty acid metabolic enzymes in human cardiomyocyte AC-16,so as to provide reference for cardiovascular protection mechanism and safe clinical application of Ophiopogon japonicus.CCK-8 (cell counting kit-8) was used to detect the effect of different concentrations of ophiopogonin D on the viability of cardiomyocytes.Meanwhile,the effect of different concentrations of ophiopogonin D on the morphology and quantity of cardiomyocytes was observed under microscope.The effect of ophiopogonin D on the mRNA expression of CYP2J2,CYP4F3,CYP4A11,CYP4A22 and CYP4F2 in cardiomyocytes was detected by RT-PCR.Western blot was used to detect the protein expression of CYP4F3 in different concentrations of ophiopogonin D.Compared with the control group,low-concentration ophiopogonin D had no effect on the viability of cardiomyocytes.However,ophiopogonin D with a concentration of higher than 20μmol·L~(-1)could promote the viability.Under the microscope,ophiopogonin D with a concentration of below 100μmol·L~(-1)had no significant effect on the morphology and number of cardiomyocytes.RT-PCR results showed that compared with the control group,5μmol·L~(-1)ophiopogonin D could slightly up-regulate mRNA expressions of CYP2J2 and CYP4F3,while high-concentration ophiopogonin D (10 and 20μmol·L~(-1)) could significantly induce mRNA expressions of CYP2J2and CYP4F3 in a dose-dependent manner (P<0.05).The same concentration of ophiopogonin D had a little effect on the mRNA expressions of CYP4A11,CYP4A22 and CYP4F2.Western blot results showed that 20μmol·L~(-1)ophiopogonin D could significantly induce the protein expression of CYP4F3 in a dose-dependent manner (P<0.05).Based on the above results,ophiopogonin D (less than100μmol·L~(-1)) has no effect on the viability of AC-16 cardiomyocytes.Ophiopogonin D (less than 100μmol·L~(-1)) can selectively induce the expressions of CYP2J2 and CYP4F3,regulate the metabolic pathway of fatty acid signaling molecules,and thus protecting the cardiovascular system.

Disparate roles of retinoid acid signaling molecules in kidney disease.

Retinoid acid (RA) is synthesized mainly in the liver and has multiple functions in development, cell differentiation and proliferation, and regulation of inflammation. RA has been used to treat multiple diseases, such as cancer and skin disorders. The kidney is a major organ for RA metabolism, which is altered in the diseased condition. RA is known to have renal-protective effects in multiple animal models of kidney disease. RA has been shown to ameliorate podocyte injury through induction of expression of differentiation markers and regeneration of podocytes from its progenitor cells in animal models of kidney disease. The effects of RA in podocytes are mediated mainly by activation of the cAMP/PKA pathway via RA receptor-α (RARα) and activation of its downstream transcription factor, Kruppel-like factor 15. Screening of RA signaling molecules in human kidney disease has revealed RAR responder protein 1 (RARRES1) as a risk gene for glomerular disease progression. RARRES1, a podocyte-specific growth arrest gene, is regulated by high doses of both RA and TNF-α. Mechanistically, RARRES1 is cleaved by matrix metalloproteinases to generate soluble RARRES1, which then induces podocyte apoptosis through interaction with intracellular RIO kinase 1. Therefore, a high dose of RA may induce podocyte toxicity through upregulation of RARRES1. Based on the current findings, to avoid potential side effects, we propose three strategies to develop future therapies of RA for glomerular disease: 1) develop RARα- and Kruppel-like factor 15-specific agonists, 2) use the combination of a low dose of RAR-α agonist with phosphodiesterase 4 inhibitors, and 3) use a combination of RARα agonist with RARRES1 inhibitors.NEW & NOTEWORTHY Retinoic acid (RA) exerts pleotropic cellular effects, including induction of cell differentiation while inhibiting proliferation and inflammation. These effects are mediated by both RA responsive element-dependent or -independent pathways. In kidneys, RA confers renoprotection by signaling through podocyte RA receptor (RAR)α and activation of cAMP/PKA/Kruppel-like factor 15 pathway to promote podocyte differentiation. Nevertheless, in kidney disease settings, RA can also promote podocyte apoptosis and loss through downstream expression of RAR responder protein 1, a recently described risk factor for glomerular disease progression. These disparate roles of RA underscore the complexity of its effects in kidney homeostasis and disease, and a need to target specific RA-mediated pathways for effective therapeutic treatments against kidney disease progression.

Bile Acid Signal Molecules Associate Temporally with Respiratory Inflammation and Microbiome Signatures in Clinically Stable Cystic Fibrosis Patients

Cystic fibrosis (CF) is a congenital disorder resulting in a multisystemic impairment in ion homeostasis. The subsequent alteration of electrochemical gradients severely compromises the function of the airway epithelia. These functional changes are accompanied by recurrent cycles of inflammation–infection that progressively lead to pulmonary insufficiency. Recent developments have pointed to the existence of a gut–lung axis connection, which may modulate the progression of lung disease. Molecular signals governing the interplay between these two organs are therefore candidate molecules requiring further clinical evaluation as potential biomarkers. We demonstrate a temporal association between bile acid (BA) metabolites and inflammatory markers in bronchoalveolar lavage fluid (BALF) from clinically stable children with CF. By modelling the BALF-associated microbial communities, we demonstrate that profiles enriched in operational taxonomic units assigned to supraglottic taxa and opportunistic pathogens are closely associated with inflammatory biomarkers. Applying regression analyses, we also confirmed a linear link between BA concentration and pathogen abundance in BALF. Analysis of the time series data suggests that the continuous detection of BAs in BALF is linked to differential ecological succession trajectories of the lung microbiota. Our data provide further evidence supporting a role for BAs in the early pathogenesis and progression of CF lung disease.

Whole-Genome Sequencing Analysis of Quorum Quenching Bacterial Strain Acinetobacter lactucae QL-1 Identifies the FadY Enzyme for Degradation of the Diffusible Signal Factor.

The diffusible signal factor (DSF) is a fatty acid signal molecule and is widely conserved in various Gram-negative bacteria. DSF is involved in the regulation of pathogenic virulence in many bacterial pathogens, including Xanthomonas campestris pv. campestris (Xcc). Quorum quenching (QQ) is a potential approach for preventing and controlling DSF-mediated bacterial infections by the degradation of the DSF signal. Acinetobacter lactucae strain QL-1 possesses a superb DSF degradation ability and effectively attenuates Xcc virulence through QQ. However, the QQ mechanisms in strain QL-1 are still unknown. In the present study, whole-genome sequencing and comparative genomics analysis were conducted to identify the molecular mechanisms of QQ in strain QL-1. We found that the fadY gene of QL-1 is an ortholog of Xcc rpfB, a known DSF degradation gene, suggesting that strain QL-1 is capable of inactivating DSF by QQ enzymes. The results of site-directed mutagenesis indicated that fadY is required for strain QL-1 to degrade DSF. The determination of FadY activity in vitro revealed that the fatty acyl-CoA synthetase FadY had remarkable catalytic activity. Furthermore, the expression of fadY in transformed Xcc strain XC1 was investigated and shown to significantly attenuate bacterial pathogenicity on host plants, such as Chinese cabbage and radish. This is the first report demonstrating a DSF degradation enzyme from A. lactucae. Taken together, these findings shed light on the QQ mechanisms of A. lactucae strain QL-1, and provide useful enzymes and related genes for the biocontrol of infectious diseases caused by DSF-dependent bacterial pathogens.

NCSTN Gene Silencing Inhibits the Retinoic Acid Signaling Pathway in Human Immortalized Keratinocytes

Abstract Objective: Acne inversa is a multifactorial chronic debilitating disease. Genetic factors are involved in 40% of patients, especially the nicastrin (NCSTN) gene. However, the role of the mutated NCSTN gene in the pathogenesis of acne inversa remains unclear. Retinoic acid is recommends to treat moderate to severe acne inversa, therefor we conduct this in vitro research to study the association between NCSTN gene mutation and the retinoic acid signaling pathway in human immortalized skin keratinocyte (HaCaT) cells. Methods: HaCaT cells were infected with a lentivirus-mediated short hairpin RNA (shRNA) expression plasmid specifically targeting the NCSTN gene. Real-time polymerase chain reaction (PCR) and Western blotting were used to detect the interference efficiency of NCSTN. RNA sequencing was used to detect differential genes in the NSCTN-deficient HaCaT cells. Based on bioinformatics analysis and clinical treatment data, the retinoic acid signal pathway was selected for screening. Quantitative PCR was used to verify the changes in the expressions of retinoic acid signaling pathway-related receptors and molecules in the HaCaT cell line after NCSTN silencing. The Student t test and one-way analysis of variance were used to evaluate intergroup differences. Results: Sequencing showed that the NCSTN-shRNA lentiviral recombinant expression plasmid was successfully constructed. After lentivirus infection of HaCaT cells, real-time PCR results showed significantly reduced NCSTN mRNA expression in the interference group compared with the negative control group, and the interference efficiency was 75.0%. Western blotting showed that the inhibition rate of NCSTN protein expression in the shRNA group was 71.7%. RNA sequencing revealed significant differential expression of some genes, and changes in signaling pathways. Compared with the control group, the group with the silenced NCSTN showed significantly decreased expression of retinoic acid receptors (RARα: F=23.482, RARβ: F=603.241, RXRα: F=69.689, and RARRES1: F=167.482, and all P < 0.001), and peroxisome proliferator-activated receptor γ (F=8.138, P < 0.01). Conclusion: Defective function of the NCSTN gene leads to an impaired retinoic acid signaling pathway in HaCaT cells, which suggests that the retinoic acid signaling pathway may play a role on the onset of acne inversa caused by NCSTN gene mutation.

Auxin-salicylic acid cross-talk ameliorates OsMYB–R1 mediated defense towards heavy metal, drought and fungal stress

The MYB TF family is an immensely large and functionally diverse class of proteins involved in the regulation of cell cycle, cell morphogenesis to stress signaling mechanism. The present study deciphered the hormonal cross-talk of wound inducible and stress-responsive OsMYB-R1 transcription factor in combating abiotic [Cr(VI) and drought/PEG] as well as biotic (Rhizoctonia solani) stress. OsMYB-R1 over-expressing rice transgenics exhibit a significant increase in lateral roots, which may be associated with increased tolerance under Cr(VI) and drought exposure. In contrast, its loss-of-function reduces stress tolerance. Higher auxin accumulation in the OsMYB-R1 over-expressed lines further strengthens the protective role of lateral roots under stress conditions. RNA-seq. data reveals over-representation of salicylic acid signaling molecule calcium-dependent protein kinases, which probably activate the stress-responsive downstream genes (Peroxidases, Glutathione S-transferases, Osmotins, Heat Shock Proteins, Pathogenesis Related-Proteins). Enzymatic studies further confirm OsMYB-R1 mediated robust antioxidant system as catalase, guaiacol peroxidase and superoxide dismutase activities were found to be increased in the over-expressed lines. Our results suggest that OsMYB-R1 is part of a complex network of transcription factors controlling the cross-talk of auxin and salicylic acid signaling and other genes in response to multiple stresses by modifying molecular signaling, internal cellular homeostasis and root morphology.

New insight into bacterial social communication in natural host: Evidence for interplay of heterogeneous and unison quorum response.

Many microbes exhibit quorum sensing (QS) to cooperate, share and perform a social task in unison. Recent studies have shown the emergence of reversible phenotypic heterogeneity in the QS-responding pathogenic microbial population under laboratory conditions as a possible bet-hedging survival strategy. However, very little is known about the dynamics of QS-response and the nature of phenotypic heterogeneity in an actual host-pathogen interaction environment. Here, we investigated the dynamics of QS-response of a Gram-negative phytopathogen Xanthomonas pv. campestris (Xcc) inside its natural host cabbage, that communicate through a fatty acid signal molecule called DSF (diffusible signal factor) for coordination of several social traits including virulence functions. In this study, we engineered a novel DSF responsive whole-cell QS dual-bioreporter to measure the DSF mediated QS-response in Xcc at the single cell level inside its natural host plant in vivo. Employing the dual-bioreporter strain of Xcc, we show that QS non-responsive cells coexist with responsive cells in microcolonies at the early stage of the disease; whereas in the late stages, the QS-response is more homogeneous as the QS non-responders exhibit reduced fitness and are out competed by the wild-type. Furthermore, using the wild-type Xcc and its QS mutants in single and mixed infection studies, we show that QS mutants get benefit to some extend at the early stage of disease and contribute to localized colonization. However, the QS-responding cells contribute to spread along xylem vessel. These results contrast with the earlier studies describing that expected cross-induction and cooperative sharing at high cell density in vivo may lead to synchronize QS-response. Our findings suggest that the transition from heterogeneity to homogeneity in QS-response within a bacterial population contributes to its overall virulence efficiency to cause disease in the host plant under natural environment.

Duodenal Peyer's Patch Gene Expression Altered Following Rodent Vertical Sleeve Gastrectomy

Bariatric surgery as a method of long term surgical associated weight loss continues to grow in popularity due to the positive metabolic health benefits reported; however, the mechanisms that produce surgical weight loss are not yet fully understood. In previous studies using our rodent model of vertical sleeve gastrectomy (VSG), it was reported that VSG results in uninhibited gastric emptying resulting in remodeling of the duodenum and various other structural changes within the intestine. We anticipate that the remodeling of the intestine would drive changes in the immune milieu of the gut. The objective of this study is to investigate the effect VSG has on the gene expression of the Peyer's patches, a component of gut‐associated lymphoid tissue that lie beneath the mucosal layer and monitor intestinal bacteria population to prevent the growth of pathogenic bacteria in the intestines. We evaluated male Long Evans rats (N=13) having received Sham‐Surgery or VSG and fed a standard chow diet post‐operatively. VSG animals lost significant amounts of body mass and fat mass and ate less in comparison to sham males during the first 5 post‐operative weeks. During post‐operative week 16, animals were euthanized and intestinal Peyer's patches were harvested for gene expression studies. RNAseq coupled with further data analysis using Illumina Software coupled with Ingenuity Pathway Analysis Software (IPA) was performed on duodenal Peyer's patches from Sham and VSG. The top Canonical Pathways having differentially‐expressed genes include LPS/IL‐1 Family, FXR Activation and Fatty Acid Activation Canonical Pathways. After determining relevant genes of interest, rtPCR was performed to validate the RNAseq data. We reported a significant decrease in tight junction‐associated claudin (CLDN8, P < 0.05) as well as increases in the facilitated glucose transporter (SLC2A4, P < 0.05), fatty acid signaling molecule (APOE, P < 0.05), and macrophage marker (CD68, P < 0.05). We have further preliminary evidence that there is elevated lipopolysaccharide binding protein (LBP) in circulation of VSG in comparison to Sham. Taken together, these data suggested a reduced intestinal barrier that leads to compromised intestinal integrity and reorganized PP architecture.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A proposed role for diffusible signal factors in the biofilm formation and morphological transformation of Helicobacter pylori.

Due to the increasing resistance of Helicobacter pylori to antibiotics, there is a growing need for new strategies for the effective eradication of this pathogen. The inhibition of quorum-sensing activity in most microorganisms leads to a decrease in virulence. A different reaction is observed in H. pylori, as interfering with the production of autoinducer-2 initiates biofilm formation and increases the survival of these bacteria. Therefore, it is believed that there is an alternative way to control the physiological changes of H. pylori exposed to environmental stress. In this article, we present the compounds probably involved in the modulation of H. pylori virulence. Diffusible signal factors (DSFs) are fatty acid signal molecules involved in communication between microbes. DSFs are likely to stimulate H. Pylori transition into a sedentary state that correlates with bacterial transformation into a more resistant coccoid form and initiates biofilm formation. Biofilm is a structure that plays a crucial role in protecting against adverse environmental factors (low pH, oxidative stress, action of immune system) and limiting the effective concentration of antimicrobial substances. This article has suggested and characterized the existence of an alternative DSF-mediated cell-cell signaling of H. pylori, which controls autoaggregative behaviors, biofilm formation, and the transition of microorganisms into the coccoid form.

Beyond detoxification: a role for mouse mEH in the hepatic metabolism of endogenous lipids

Microsomal and soluble epoxide hydrolase (mEH and sEH) fulfill apparently distinct roles: Whereas mEH detoxifies xenobiotics, sEH hydrolyzes fatty acid (FA) signaling molecules and is thus implicated in a variety of physiological functions. These epoxy FAs comprise epoxyeicosatrienoic acids (EETs) and epoxy-octadecenoic acids (EpOMEs), which are formed by CYP epoxygenases from arachidonic acid (AA) and linoleic acid, respectively, and then are hydrolyzed to their respective diols, the so-called DHETs and DiHOMEs. Although EETs and EpOMEs are also substrates for mEH, its role in lipid signaling is considered minor due to lower abundance and activity relative to sEH. Surprisingly, we found that in plasma from mEH KO mice, hydrolysis rates for 8,9-EET and 9,10-EpOME were reduced by 50% compared to WT plasma. This strongly suggests that mEH contributes substantially to the turnover of these FA epoxides—despite kinetic parameters being in favor of sEH. Given the crucial role of liver in controlling plasma diol levels, we next studied the capacity of sEH and mEH KO liver microsomes to synthesize DHETs with varying concentrations of AA (1–30 μM) and NADPH. mEH-generated DHET levels were similar to the ones generated by sEH, when AA concentrations were low (1 μM) or epoxygenase activity was curbed by modulating NADPH. With increasing AA concentrations sEH became more dominant and with 30 μM AA produced twice the level of DHETs compared to mEH. Immunohistochemistry of C57BL/6 liver slices further revealed that mEH expression was more widespread than sEH expression. mEH immunoreactivity was detected in hepatocytes, Kupffer cells, endothelial cells, and bile duct epithelial cells, while sEH immunoreactivity was confined to hepatocytes and bile duct epithelial cells. Finally, transcriptome analysis of WT, mEH KO, and sEH KO liver was carried out to discern transcriptional changes associated with the loss of EH genes along the CYP-epoxygenase–EH axis. We found several prominent dysregulations occurring in a parallel manner in both KO livers: (a) gene expression of Ephx1 (encoding for mEH protein) was increased 1.35-fold in sEH KO, while expression of Ephx2 (encoding for sEH protein) was increased 1.4-fold in mEH KO liver; (b) Cyp2c genes, encoding for the predominant epoxygenases in mouse liver, were mostly dysregulated in the same manner in both sEH and mEH KO mice, showing that loss of either EH has a similar impact. Taken together, mEH appears to play a leading role in the hydrolysis of 8,9-EET and 9,10-EpOME and also contributes to the hydrolysis of other FA epoxides. It probably profits from its high affinity for FA epoxides under non-saturating conditions and its close physical proximity to CYP epoxygenases, and compensates its lower abundance by a more widespread expression, being the only EH present in several sEH-lacking cell types.

Expression Analysis of Genes Related to Rice Resistance Against Brown Planthopper, Nilaparvata lugens

Brown planthopper (BPH) is an insect species that feeds on the vascular system of rice plants. To examine the defence mechanism of rice plants against BPH, the pathogenesis-related genes (PR1a, PR2, PR3, PR4, PR6, PR9, PR10a, PR13, PR15 and PRpha), signaling molecule synthesis genes (AOS, AXR, ACO and LOX), antioxidant-related genes (CAT, TRX, GST and SOD) and lignin biosynthesis-related genes (CHS, CHI and C4H) were investigated in a resistant rice variety. AOS, PR6, PR9 and PR15 genes showed significantly increased relative expression levels at 24.38-, 19.17-, 14.71-, and 12.74-fold compared to the control. Moderate increased relative expression levels of lignin biosynthesis-related gene (C4H), pathogenesis-related genes (PR4, PR10a and PRpha), and antioxidant-related gene (GST) were found, while CHI, LOX, SOD, TRX1 and AXR showed decreased relative expression levels. It was thus clearly shown that wound-induced response genes were activated in rice plants after BPH attacks through AOS activation. Jasmonic acid signaling molecule may activate PR6, PR15, GST and CAT subsequently increasing their expression for H2O2 detoxification. PR6 were expressed at the highest relative level among the PR genes. These genes therefore have also a considerable synergistic role with the other genes against BPH by interfered their digestion tract system.

Signal molecules involved in the regulation of the wheat defense response to Septoria nodorum infection

The response of Triticum aestivum L. to infection by Septoria nodorum Berk, a pathogen causing speckled leaf blotch, was studied. The effect of salicylic acid (SA) and jasmonic acid (JA) signal molecules, as well as chitooligosaccharides (COSs) with different acetylation degrees (ADs), on the accumulation of hydrogen peroxide (Н2О2) in wheat leaves and the pathogenesis-related (PR) proteins of oxalate oxidase (AJ556991.1), peroxidase (TC 151917), and proteinase inhibitor (EU293132.1) was investigated. Treatment with the signal molecules inhibited S. nodorum growth and stimulated Н2О2 accumulation, as well as PR gene expression. SA and COS with 65% AD are found to be more efficient in Н2О2 induction and elevation of the transcriptional level of the oxalate oxidase and peroxidase genes. At the same time, JA and COS with 30% AD stimulated transcription of the proteinase inhibitor gene. The results suggest the existence of differential means of defense response induction by signal molecules with more prospects for the regulation of plant immunity.

Soluble epoxide hydrolase inhibitor enhances synaptic neurotransmission and plasticity in mouse prefrontal cortex

BackgroundThe soluble epoxide hydrolase (sEH) is an important enzyme chiefly involved in the metabolism of fatty acid signaling molecules termed epoxyeicosatrienoic acids (EETs). sEH inhibition (sEHI) has proven to be protective against experimental cerebral ischemia, and it is emerging as a therapeutic target for prevention and treatment of ischemic stroke. However, the role of sEH on synaptic function in the central nervous system is still largely unknown. This study aimed to test whether sEH C-terminal epoxide hydrolase inhibitor, 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) affects basal synaptic transmission and synaptic plasticity in the prefrontal cortex area (PFC). Whole cell and extracellular recording examined the miniature excitatory postsynaptic currents (mEPSCs) and field excitatory postsynaptic potentials (fEPSPs); Western Blotting determined the protein levels of glutamate receptors and ERK phosphorylation in acute medial PFC slices.ResultsApplication of the sEH C-terminal epoxide hydrolase inhibitor, AUDA significantly increased the amplitude of mEPSCs and fEPSPs in prefrontal cortex neurons, while additionally enhancing long term potentiation (LTP). Western Blotting demonstrated that AUDA treatment increased the expression of the N-methyl-D-aspartate receptor (NMDA) subunits NR1, NR2A, NR2B; the α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1, GluR2, and ERK phosphorylation.ConclusionsInhibition of sEH induced an enhancement of PFC neuronal synaptic neurotransmission. This enhancement of synaptic neurotransmission is associated with an enhanced postsynaptic glutamatergic receptor and postsynaptic glutamatergic receptor mediated synaptic LTP. LTP is enhanced via ERK phosphorylation resulting from the delivery of glutamate receptors into the PFC by post-synapse by treatment with AUDA. These findings provide a possible link between synaptic function and memory processes.