Role Of Second Messengers Research Articles

Neem leaf glycoprotein binding to Dectin-1 receptors on dendritic cell induces type-1 immunity through CARD9 mediated intracellular signal to NFκB

BackgroundA water-soluble ingredient of mature leaves of the tropical mahogany ‘Neem’ (Azadirachta indica), was identified as glycoprotein, thus being named as ‘Neem Leaf Glycoprotein’ (NLGP). This non-toxic leaf-component regressed cancerous murine tumors (melanoma, carcinoma, sarcoma) recurrently in different experimental circumstances by boosting prime antitumor immune attributes. Such antitumor immunomodulation, aid cytotoxic T cell (Tc)-based annihilation of tumor cells. This study focused on identifying and characterizing the signaling gateway that initiate this systemic immunomodulation. In search of this gateway, antigen-presenting cells (APCs) were explored, which activate and induce the cytotoxic thrust in Tc cells.MethodsSix glycoprotein-binding C-type lectins found on APCs, namely, MBR, Dectin-1, Dectin-2, DC-SIGN, DEC205 and DNGR-1 were screened on bone marrow-derived dendritic cells from C57BL/6 J mice. Fluorescence microscopy, RT-PCR, flow cytometry and ELISA revealed Dectin-1 as the NLGP-binding receptor, followed by verifications through RNAi. Following detection of β-Glucans in NLGP, their interactions with Dectin-1 were explored in silico. Roles of second messengers and transcription factors in the downstream signal were studied by co-immunoprecipitation, western blotting, and chromatin-immunoprecipitation. Intracellularization of FITC-coupled NLGP was observed by processing confocal micrographs of DCs.ResultsConsidering extents of hindrance in NLGP-driven transcription rates of the cytokines IL-10 and IL-12p35 by receptor-neutralization, Dectin-1 receptors on dendritic cells were found to bind NLGP through the ligand’s peripheral β-Glucan chains. The resulting signal phosphorylates PKCδ, forming a trimolecular complex of CARD9, Bcl10 and MALT1, which in turn activates the canonical NFκB-pathway of transcription-regulation. Consequently, the NFκB-heterodimer p65:p50 enhances Il12a transcription and the p50:p50 homodimer represses Il10 transcription, bringing about a cytokine-based systemic-bias towards type-1 immune environment. Further, NLGP gets engulfed within dendritic cells, possibly through endocytic activities of Dectin-1.ConclusionNLGP’s binding to Dectin-1 receptors on murine dendritic cells, followed by the intracellular signal, lead to NFκB-mediated contrasting regulation of cytokine-transcriptions, initiating a pro-inflammatory immunopolarization, which amplifies further by the responding immune cells including Tc cells, alongside their enhanced cytotoxicity. These insights into the initiation of mammalian systemic immunomodulation by NLGP at cellular and molecular levels, may help uncovering its mode of action as a novel immunomodulator against human cancers, following clinical trials.

An atypical GdpP enzyme linking cyclic nucleotide metabolism to osmotic tolerance and gene regulation in Mycoplasma bovis

Nucleotide second messengers play an important role in bacterial adaptation to environmental changes. Recent evidence suggests that some of these regulatory molecular pathways were conserved upon the degenerative evolution of the wall-less mycoplasmas. We have recently reported the occurrence of a phosphodiesterase (PDE) in the ruminant pathogen Mycoplasma bovis, which was involved in c-di-AMP metabolism. In the present study, we demonstrate that the genome of this mycoplasma species encodes a PDE of the GdpP family with atypical DHH domains. Characterization of M. bovis GdpP (MbovGdpP) revealed a multifunctional PDE with unusual nanoRNase and single-stranded DNase activities. The alarmone ppGpp was found unable to inhibit c-di-NMP degradation by MbovGdpP but efficiently blocked its nanoRNase activity. Remarkably, MbovGdpP was found critical for the osmotic tolerance of M. bovis under K+ and Na+ conditions. Transcriptomic analyses further revealed the biological importance of MbovGdpP in tRNA biosynthesis, pyruvate metabolism, and several steps in genetic information processing. This study is an important step in understanding the role of PDE and nucleotide second messengers in the biology of a minimal bacterial pathogen.

Network-driven intracellular cAMP coordinates circadian rhythm in the suprachiasmatic nucleus.

The mammalian central circadian clock, located in the suprachiasmatic nucleus (SCN), coordinates the timing of physiology and behavior to local time cues. In the SCN, second messengers, such as cAMP and Ca2+, are suggested to be involved in the input and/or output of the molecular circadian clock. However, the functional roles of second messengers and their dynamics in the SCN remain largely unclear. In the present study, we visualized the spatiotemporal patterns of circadian rhythms of second messengers and neurotransmitter release in the SCN. Here, we show that neuronal activity regulates the rhythmic release of vasoactive intestinal peptides from the SCN, which drives the circadian rhythms of intracellular cAMP in the SCN. Furthermore, optical manipulation of intracellular cAMP levels in the SCN shifts molecular and behavioral circadian rhythms. Together, our study demonstrates that intracellular cAMP is a key molecule in the organization of the SCN circadian neuronal network.

Roles of second messengers in the regulation of cyanobacterial physiology: the carbon-concentrating mechanism and beyond.

Second messengers are a fundamental category of small molecules and ions that are involved in the regulation of many processes in all domains of life. Here we focus on cyanobacteria, prokaryotes playing important roles as primary producers in the geochemical cycles due to their capability of oxygenic photosynthesis and carbon and nitrogen fixation. Of particular interest is the inorganic carbon-concentrating mechanism (CCM), which allows cyanobacteria to concentrate CO2 near RubisCO. This mechanism needs to acclimate toward fluctuating conditions, such as inorganic carbon availability, intracellular energy levels, diurnal light cycle, light intensity, nitrogen availability, and redox state of the cell. During acclimation to such changing conditions, second messengers play a crucial role, particularly important is their interaction with the carbon control protein SbtB, a member of the PII regulator protein superfamily. SbtB is capable of binding several second messengers, uniquely adenyl nucleotides, to interact with different partners in a variety of responses. The main identified interaction partner is the bicarbonate transporter SbtA, which is regulated via SbtB depending on the energy state of the cell, the light conditions, and different CO2 availability, including cAMP signaling. The interaction with the glycogen branching enzyme, GlgB, showed a role for SbtB in the c-di-AMP-dependent regulation of glycogen synthesis during the diurnal life cycle of cyanobacteria. SbtB has also been shown to impact gene expression and metabolism during acclimation to changing CO2 conditions. This review summarizes the current knowledge about the complex second messenger regulatory network in cyanobacteria, with emphasis on carbon metabolism.

Roles of Intracellular Second Messengers in Mediation of a7-nAChR-induced Modulations

Nicotinic acetylcholine receptors (nAChRs) are the members of the cys-loop ligandgated ion channel superfamily. They are cation-selective membrane proteins with a homopentameric or heteropentameric structure. The α7 subtype of nAChR (α7-nAChR) belongs to the classical homopentameric structure with the characteristics of relatively low affinity to agonists and high permeability to Ca2+. α7-nAChR plays an important role in modulating learning and memory, cognition, anti-inflammatory, growth and development, and other processes. There are many possible mechanisms underlying α7-nAChR-mediated modulations, including opening the high Ca2+ permeable channels, regulating presynaptic neurotransmitter release, and altering intracellular second messenger-mediated signaling pathways. Here, we summarize the signal pathways associated with α7-nAChR activation involving nucleotides, ions, lipids, and gas molecules. This article provides insights into α7-nAChR-mediated modulations through intracellular signaling systems and helps to understand the α7-nAChR-associated pathogenesis and therapeutics of a variety of diseases and disorders.

Inhibition of ABCC1 Decreases cAMP Egress and Promotes Human Airway Smooth Muscle Cell Relaxation.

In most living cells, the second-messenger roles for adenosine 3',5'-cyclic monophosphate (cAMP) are short-lived, confined to the intracellular space, and tightly controlled by the binary switch-like actions of Gαs (stimulatory G protein)-activated adenylyl cyclase (cAMP production) and cAMP-specific PDE (cAMP breakdown). Here, by using human airway smooth muscle (HASM) cells in culture as a model, we report that activation of the cell-surface β2AR (β2-adrenoceptor), a Gs-coupled GPCR (G protein-coupled receptor), evokes cAMP egress to the extracellular space. Increased extracellular cAMP levels ([cAMP]e) are long-lived in culture and are induced by receptor-dependent and receptor-independent mechanisms in such a way as to define a universal response class of increased intracellular cAMP levels ([cAMP]i). We find that HASM cells express multiple ATP-binding cassette (ABC) membrane transporters, with ABCC1 (ABC subfamily member C 1) being the most highly enriched transcript mapped to MRPs (multidrug resistance-associated proteins). We show that pharmacological inhibition or downregulation of ABCC1 with siRNA markedly reduces β2AR-evoked cAMP release from HASM cells. Furthermore, inhibition of ABCC1 activity or expression decreases basal tone and increases β-agonist-induced HASM cellular relaxation. These findings identify a previously unrecognized role for ABCC1 in the homeostatic regulation of [cAMP]i in HASM that may be conserved traits of the Gs-GPCRs (Gs-coupled family of GPCRs). Hence, the general features of this activation mechanism may uncover new disease-modifying targets in the treatment of airflow obstruction in asthma. Surprisingly, we find that serum cAMP levels are elevated in a small cohort of patients with asthma as compared with control subjects, which warrants further investigation.

Interplay between the cyclic di-GMP network and the cell-cell signalling components coordinates virulence-associated functions in Xanthomonas oryzae pv. oryzae.

Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in Xoo. However, the role of important second messenger c-di-GMP signalling in the regulation of virulence-associated functions still remains elusive in this phytopathogen. In this study we have performed an investigation of 13 c-di-GMP modulating deletion mutants to understand their contribution in Xoo virulence and lifestyle transition. We show that four Xoo proteins, Xoo2331, Xoo2563, Xoo2860 and Xoo2616, are involved in fine-tuning the in vivo c-di-GMP abundance and also play a role in the regulation of virulence-associated functions. We have further established the importance of the GGDEF domain of Xoo2563, a previously characterized c-di-GMP phosphodiesterase, in the virulence-associated functions of Xoo. Interestingly the strain harbouring the GGDEF domain deletion (ΔXoo2563GGDEF ) exhibited EPS deficiency and hypersensitivity to streptonigrin, indicative of altered iron metabolism. This is in contrast to the phenotype exhibited by an EAL overexpression strain wherein, the ΔXoo2563GGDEF exhibited other phenotypes, similar to the strain overexpressing the EAL domain. Taken together, our results indicate a complex interplay of c-di-GMP signalling with the cell-cell signalling to coordinate virulence-associated function in Xoo.

Motility, Adhesion and c-di-GMP Influence the Endophytic Colonization of Rice by Azoarcus sp. CIB.

Proficient crop production is needed to ensure the feeding of a growing global population. The association of bacteria with plants plays an important role in the health state of the plants contributing to the increase of agricultural production. Endophytic bacteria are ubiquitous in most plant species providing, in most cases, plant promotion properties. However, the knowledge on the genetic determinants involved in the colonization of plants by endophytic bacteria is still poorly understood. In this work we have used a genetic approach based on the construction of fliM, pilX and eps knockout mutants to show that the motility mediated by a functional flagellum and the pili type IV, and the adhesion modulated by exopolysaccarides are required for the efficient colonization of rice roots by the endophyte Azoarcus sp. CIB. Moreover, we have demonstrated that expression of an exogenous diguanylate cyclase or phophodiesterase, which causes either an increase or decrease of the intracellular levels of the second messenger cyclic di-GMP (c-di-GMP), respectively, leads to a reduction of the ability of Azoarcus sp. CIB to colonize rice plants. Here we present results demonstrating the unprecedented role of the universal second messenger cyclic-di-GMP in plant colonization by an endophytic bacterium, Azoarcus sp. CIB. These studies pave the way to further strategies to modulate the interaction of endophytes with their target plant hosts.

Molecular Mechanisms of Autophagy Regulation in Plants and Their Applications in Agriculture.

Autophagy is a highly conserved cellular process for the degradation and recycling of unnecessary cytoplasmic components in eukaryotes. Various studies have shown that autophagy plays a crucial role in plant growth, productivity, and survival. The extensive functions of plant autophagy have been revealed in numerous frontier studies, particularly those regarding growth adjustment, stress tolerance, the identification of related genes, and the involvement of metabolic pathways. However, elucidation of the molecular regulation of plant autophagy, particularly the upstream signaling elements, is still lagging. In this review, we summarize recent progress in research on the molecular mechanisms of autophagy regulation, including the roles of protein kinases, phytohormones, second messengers, and transcriptional and epigenetic control, as well as the relationship between autophagy and the 26S proteasome in model plants and crop species. We also discuss future research directions for the potential application of autophagy in agriculture.

Mathematical model pertaining to the effect of buffer over cytosolic calcium concentration distribution

The study of calcium dynamics is an important aspect as it regulates various processes viz metabolism, secretion etc. and also play the key role of second messenger. In the present work our main focus is over the variation of the cellular calcium with the various buffers after solving the advection-diffusion equation for the cellular calcium with inclusion of the calcium-binding buffers also. The presence of buffer lower the cellular calcium level and prevents its toxicity within cell. Buffers play key role in lowering the concentration level of cytosolic calcium, by binding with the intracellular free calcium ions. The model is incorporating association and dissociation rates, diffusion coefficients and buffer concentration. The fractional model for this is developed by using the Caputo-Fabrizio operator. The corresponding boundary and initial conditions are also framed accordingly. The integral transform technique is applied to obtain the analytical solution and simulation has been done to observe the effect of buffer on the distribution of calcium concentration.

The potential role of neuroinflammation and synaptic plasticity for neuropsychiatric symptoms

AbstractBackgroundNeuropsychiatric symptoms (NPS) show a high prevalence within Alzheimer’s dementia. Evidence from animals and humans suggest a role of inflammatory cytokines and second messengers related to synaptic plasticity such as cGMP in Alzheimer´s disease (AD). In addition, studies show associations of serum interleukins (IL) and cGMP with NPS. However, the role of different ILs and cGMP in the pathogenesis of NPS is still not fully clear and studies on CSF are lacking. This study examines the associations between NPS with different established AD markers, pro‐ and anti‐inflammatory ILs and cGMP in the CSF.MethodCSF and Serum samples of 120 patients with SCI, MCI or dementia and 19 controls who were previously examined at the memory clinic Ulm were analysed for this study. In clinical routine NPS were assessed by the neuropsychiatric inventory (NPI) total score and the Geriatric Depression Scale‐15 (GDS). Cytokines were determined by MSD V‐Plex assay in serum and CSF of patients, cGMP was determined by ELISA in CSF. Linear and binary logistic regression models were used for investigation. Bootstrapping was used if model assumptions were not fulfilled. Analyses were adjusted for ApoE genotype, age, gender and education. Additionally, an exhaustive screening for predictive marker combinations was performed (NPI>9, yes/no).ResultThe NPI total score was not associated with any of the evaluated ILs, but there was a positive association with CSF‐Abeta‐42 (β = .20, p = .038). Higher cGMP was associated with a lower OR for NPI>9 (OR = 0.69, p = .012). GDS was positively associated with IL‐1RA (β = .20, p = .029). IL‐6 was negatively associated with CSF‐Abeta‐42 (β = ‐0.09, p = .035). The predictive models achieved a maximal accuracy of 67.3%.ConclusionThis study is one of the first, examining the relationship between CSF inflammatory cytokines, cGMP, AD pathology and NPS in memory clinic outpatients. The results indicate a role of cGMP in NPS. Furthermore, results indicate a potential role of ILs in depression in older adults (IL‐1RA) and in AD. Because of the risk for alpha‐error inflation due to multiple comparisons, further research is needed to replicate these findings.

Control of mRNA translation by dynamic ribosome modification.

Control of mRNA translation is a crucial regulatory mechanism used by bacteria to respond to their environment. In the soil bacterium Pseudomonas fluorescens, RimK modifies the C-terminus of ribosomal protein RpsF to influence important aspects of rhizosphere colonisation through proteome remodelling. In this study, we show that RimK activity is itself under complex, multifactorial control by the co-transcribed phosphodiesterase trigger enzyme (RimA) and a polyglutamate-specific protease (RimB). Furthermore, biochemical experimentation and mathematical modelling reveal a role for the nucleotide second messenger cyclic-di-GMP in coordinating these activities. Active ribosome regulation by RimK occurs by two main routes: indirectly, through changes in the abundance of the global translational regulator Hfq and directly, with translation of surface attachment factors, amino acid transporters and key secreted molecules linked specifically to RpsF modification. Our findings show that post-translational ribosomal modification functions as a rapid-response mechanism that tunes global gene translation in response to environmental signals.

Lipids, inflammasomes, metabolism, and disease.

Inflammasomes are multi-protein complexes that regulate the cleavage of cysteine protease caspase-1, secretion of inflammatory cytokines, and induction of inflammatory cell death, pyroptosis. Several members of the nod-like receptor family assemble inflammasome in response to specific ligands. An exception to this is the NLRP3 inflammasome which is activated by structurally diverse entities. Recent studies have suggested that NLRP3 might be a sensor of cellular homeostasis, and any perturbation in distinct metabolic pathways results in the activation of this inflammasome. Lipid metabolism is exceedingly important in maintaining cellular homeostasis, and it is recognized that cells and tissues undergo extensive lipid remodeling during activation and disease. Some lipids are involved in instigating chronic inflammatory diseases, and new studies have highlighted critical upstream roles for lipids, particularly cholesterol, in regulating inflammasome activation implying key functions for inflammasomes in diseases with defective lipid metabolism. The focus of this review is to highlight how lipids regulate inflammasome activation and how this leads to the progression of inflammatory diseases. The key roles of cholesterol metabolism in the activation of inflammasomes have been comprehensively discussed. Besides, the roles of oxysterols, fatty acids, phospholipids, and lipid second messengers are also summarized in the context of inflammasomes. The overriding theme is that lipid metabolism has numerous but complex functions in inflammasome activation. A detailed understanding of this area will help us develop therapeutic interventions for diseases where dysregulated lipid metabolism is the underlying cause.

Brassinosteroids application induces phosphatidic acid production and modify antioxidant enzymes activity in tobacco in calcium-dependent manner

Brassinosteroids (BRs) are steroid hormones regulating various aspects of plant metabolism, including growth, development and stress responses. However, little is known about the mechanism of their impact on antioxidant systems and phospholipid turnover. Using tobacco plants overexpressing H+/Ca2+vacuolar Arabidopsis antiporter CAX1, we showed the role of Ca2+ ion balance in the reactive oxygen species production and rapid phosphatidic acid accumulation induced by exogenous BR. Combination of our experimental results with public transcriptomic and proteomic data revealed a particular role of Ca2+-dependent phospholipid metabolizing enzymes in BR signaling. Here we provide novel insights into the role of calcium balance and lipid-derived second messengers in plant responses to exogenous BRs and propose a complex model integrating BR-mediated metabolic changes with phospholipid turnover.

Enhanced Response to Oxytocin in Myometrium of Proven Breeder Compared to Virgin Rats Does Not Depend on Augmented Expression of Oxytocin Receptors

ObjectiveOur overall hypothesis is that pregnancy's mechanical and hormonal stimuli induce permanent changes in the properties of uterine tissue. We have shown previously that the response to oxytocin of the non‐pregnant (NP) myometrium is more pronounced in proven breeder than in virgin animals. Our objective here was to investigate some of the possible mechanisms that could produce such difference: 1) Altered number of oxytocin receptors (OXTR); 2) Altered production of intracellular prostaglandins; 3) Altered availability of voltage gated calcium channels (VGCC).MethodVirgin (V) and proven breeder (PB) NP female 18 week old rats were staged and euthanized at proestrus. One uterine horn was dissected in strips suspended in a tissue bath containing Krebs solution (in mM, NaCl 117, KCl 4.7, NaHCO3 25, MgCl2 1.2, KH2PO4 1.2, CaCl2 2.5, glucose 11, pH= 7.4) at 37°C and bubbled with 95% O2 and 5% CO2. Dose response curves to oxytocin (10E‐10 to 10E‐5 M) were recorded in the presence of indomethacin or after exposure to a 0 CaCl2 modified Krebs. The other uterine horn was flash frozen in liquid NO2 and later used for ELISA (kit from Wuhan Fine Biotech, Wuhan China) and qRT‐PCR experiments (Taqman® gene expression assays (Life Technologies) and QuantStudio™ 5 real‐time PCR system (Applied Biosystems, Grand Island, NY) were used to examine the gene of interest mRNA expression using the comparative CT method (Schmittgen and Livak, 2008).ResultsIn the ELISA experiments, NP samples showed a barely significant (32±14%, P=0.040) elevation of OXTR in V (n = 8) vs PB myometrium. This is in open contradiction to our previous motility data. To investigate whether this inversion trend in protein level is matched at the mRNA level, we evaluated OXTR gene expression in NP strips (n=5, in quadruplicates). No significant difference was detected between V and PB expression of β‐actin (P= 0.099). Instead, a significant difference was found in the OXTR gene expression (P<0.01) and the 2−ΔΔCt (RQ) was 0.18 (Min RQ=0.12, Max RQ=0.27, indicative of an 8.3 to 3.7 folds decrease in the OXTR mRNA level in PB vs V samples. On the other hand, in the presence of 10 μM indomethacin (COX inhibitor) or in the absence of extracellular calcium the differences in the responses to oxytocin in V and PB myometrial strips were attenuated (−98% and −96% respectively). This suggest important roles of second messengers activated pathways in the more robust effects of oxytocin in NP PB strips.ConclusionsWhile our previous functional experiments suggested that PB myometrium might contain a higher number of OXTR, ELISA and PCR experiments imply that the opposite might be true. The gene expression of the OXTR is frankly stronger in V, while the actual protein expression is not significantly different between V and PB. A better explanation for our pharmacological observations involves differences in the activity of channels and intracellular mechanisms activated by oxytocin, some of which we presented here and are currently under investigation.Support or Funding InformationThis study was funded by an MWU intramural research grant to MP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Neuronal and behavioral plasticity: the role of serotonin and BDNF systems tandem

ABSTRACTIntroduction: Serotonin (5-HT) and brain-derived neurotrophic factor (BDNF) are known as principal players in different kinds of plasticity. The 5-HT–BDNF interaction in early ontogeny and in adult brain is an intriguing problem.Area covered: This paper concentrates on the interaction between 5-HT and BDNF systems and its implication in different plasticity levels, from neurons to behavior. This review describes (1) different 5-HT functioning in the embryonic (as neurotrophin) and adult brain (as a neurotransmitter); (2) BDNF as a modulator of 5-HT system and vice versa; (3) the prolonged positive effect of BDNF on genetically and epigenetically defined central nervous system disorders; (4) The 5-HT–BDNF interplay contribution to aggressive behavior, depression, drug addiction, suicide, and stress response; and (5) the role of common second messengers for 5-HT and BDNF signaling in the 5-HT–BDNF interaction.Expert opinion: Dysregulation in 5-HT–BDNF interaction may be responsible for development of neuropsychiatric and behavioral abnormalities. 5-HT–BDNF cross-talk is a potential target for the treatment of various neurological diseases. Understanding the function of the members of BDNF system in response to challenges of the environment and the interaction with different 5-HT receptors in health and disease will one day lead to new classes of drugs.

THE ROLE OF ADENYLATE-CYCLASE ACTIVITY IN PLATELETS OF PATIENTS WITH OBSESSIVE-COMPULSIVE DISORDER

Introduction Blood platelets can be considered a reliable peripheral model of presynaptic serotonergic neurons, as they are endowed with a 5-HT reuptake transporter similar to that present in the brain cells (Marazziti et al., 2004). The biological basis of the patophysiology of obsessive-compulsive disorder (OCD) is centered on serotonergic system, although evidences of both dopaminergic and adrenergic systems involvement are consistent (Westenberg et al., 2007). A possible role of second messengers, such as cyclic adenosine monophosphate (cAMP) signaling, in the development of OCD has been recently postulated, although evidences are meager and, in some cases, contradictory (McDougle et al., 1999). The aim of the present study was to explore and to compare the adenylate cyclase (AC) activity either in basal conditions, either after the stimulation by isoprenaline (ISO) in platelets of OCD patients and healthy control subjects. Also, AC activity was measured both in the absence and in the presence of α- and β- adrenoreceptor antagonists. Materials and methods Forty patients (20 men and 20 women, aged between 23 and 34 years; mean±SD: 26.5 ± 4.8) were included in the study. All of them met Diagnostic and Statistic Manual of Mental Disorders 5th edition (DSM-5) criteria for OCD, were not currently depressed, nor had any history of mood disorders or any other comorbid conditions. This group was compared to a similar one, composed by 40 healthy volunteers patients (20 men and 20 women, aged between 21 and 32 years; mean±SD: 24.6 ± 6.3), all of them without familiar or personal history of major psychiatric disorders. The severity of OC symptoms was evaluated by means of the Yale Brown Obsessive-Compulsive Scale (Y-BOCS). Thirty (30) ml of blood were collected from fasting subjects between 8.00-10.00 a.m. to avoid circadian rhythm interference. Results The platelet basal AC activity was similar in OCD patients and healthy subjects. The addition of 10 μM ISO enhanced significantly (p Discussion No difference in the basal AC activity in platelet membranes of healthy subjects and OCD patients was found. The addition of 10 µM ISO to platelet membranes provoked a significant stimulation of the enzyme activity of the same magnitude in the two groups. Our findings suggests that, at our experimental conditions, there is an inhibitory component of ISO effect on platelet AC, due to the agonist interaction with α2 receptors, at its higher concentrations (> 1 μM). These data suggest the presence of a condition of supersensitive β-receptors in platelets of OCD patients that, perhaps, could reflect (or provoke) alterations of the intracellular signaling system mediated by the cAMP and of the related kinases. In conclusion, the results of the present study suggest that abnormal second messenger pathways in OCD may be also related to cathecolamine system disturbances, which might open new therapeutic strategies especially in resistant patients who do not respond to serotonergic medications.

How prokaryotes ‘encode’ their environment: Systemic tools for organizing the information flow

An important issue related to code biology concerns the cell’s informational relationships with the environment. As an open self-producing system, a great variety of inputs and outputs are necessary for the living cell, not only consisting of matter and energy but also involving information flows. The analysis here of the simplest cells will involve two basic aspects. On the one side, the molecular apparatuses of the prokaryotic signaling system, with all its variety of environmental signals and component pathways (which have been called 1–2-3 Component Systems), including the role of a few second messengers which have been pointed out in bacteria too. And in the other side, the gene transcription system as depending not only on signaling inputs but also on a diversity of factors. Amidst the continuum of energy, matter, and information flows, there seems to be evidence for signaling codes, mostly established around the arrangement of life-cycle stages, in large metabolic changes, or in the relationships with conspecifics (quorum sensing) and within microbial ecosystems. Additionally, and considering the complexity growth of signaling systems from prokaryotes to eukaryotes, four avenues or “roots” for the advancement of such complexity would come out. A comparative will be established in between the signaling strategies and organization of both kinds of cellular systems. Finally, a new characterization of “informational architectures” will be proposed in order to explain the coding spectrum of both prokaryotic and eukaryotic signaling systems. Among other evolutionary aspects, cellular strategies for the construction of novel functional codes via the intermixing of informational architectures could be related to the persistence of retro-elements with obvious viral ancestry.

The Shigella type III effector IpgD recodes Ca2+ signals during invasion of epithelial cells.

The role of second messengers in the diversion of cellular processes by pathogens remains poorly studied despite their importance. Among these, Ca2+ virtually regulates all known cell processes, including cytoskeletal reorganization, inflammation, or cell death pathways. Under physiological conditions, cytosolic Ca2+ increases are transient and oscillatory, defining the so-called Ca2+ code that links cell responses to specific Ca2+ oscillatory patterns. During cell invasion, Shigella induces atypical local and global Ca2+ signals. Here, we show that by hydrolyzing phosphatidylinositol-(4,5)bisphosphate, the Shigella type III effector IpgD dampens inositol-(1,4,5)trisphosphate (InsP3) levels. By modifying InsP3 dynamics and diffusion, IpgD favors the elicitation of long-lasting local Ca2+ signals at Shigella invasion sites and converts Shigella-induced global oscillatory responses into erratic responses with atypical dynamics and amplitude. Furthermore, IpgD eventually inhibits InsP3-dependent responses during prolonged infection kinetics. IpgD thus acts as a pathogen regulator of the Ca2+ code implicated in a versatility of cell functions. Consistent with this function, IpgD prevents the Ca2+-dependent activation of calpain, thereby preserving the integrity of cell adhesion structures during the early stages of infection.

Adenylate-cyclase activity in obsessive-compulsive patients

IntroductionA possible role of second messengers, such as cyclic adenosine monophosphate (cAMP) signalling, in the development of obsessive-compulsive disorder (OCD) has been recently postulated.AimsThe aim of the present study was to explore and to compare the adenylate cyclase (AC) activity in both basal conditions and after the stimulation by isoprenaline (ISO) in platelets of OCD patients and healthy control subjects. The AC activity was measured both in the absence and in the presence of α- and β- adrenoreceptor antagonists.Materials and methodsForty patients were included in the study and compared with healthy volunteers. Biological assays were carried out with a method developed by us.ResultsThe basal AC activity was similar in both groups. The addition of 10 μM ISO enhanced significantly (P < .05) platelet basal AC in both groups. A stimulatory response following ISO in all subjects even without α-antagonists was also observed.DiscussionNo difference in the basal AC activity in platelet membranes of healthy subjects and OCD patients was found. Our findings showed that there is an inhibitory component of ISO effect on platelet AC, due to the agonist interaction with α2 receptors, at its higher concentrations (>1 μM), as well as a condition of supersensitive β-receptors. Our study suggests the presence of cathecolamine system disturbances in OCD.Disclosure of interestThe authors have not supplied their declaration of competing interest.