Intracellular Signaling Systems Research Articles

Modified kinetics of generation of reactive species in peripheral blood of patients with type 2 diabetes

Level of reactive species in blood is an important pathogenic factor in diabetes mellitus leading to dysfunctions of vascular endothelial and smooth muscle cells and coagulation system abnormality. A massive release of reactive species (respiratory burst), catalyzed by NADPH oxidase in blood phagocytes, is not well understood in diabetes. The work aimed to study kinetics of response to microbial particles in blood to specify changes in regulatory mechanisms of generation of reactive species in patients with type 2 diabetes. Production of reactive species in blood and isolated granulocytes was measured by luminol-dependent chemiluminescence. Respiratory burst was initiated by serum opsonized zymosan in blood samples and phorbol ester in cell samples. Kinetic parameters were calculated from experimental kinetic curves of chemiluminescence intensity. ROC curve analysis and mathematical modeling were used to reveal the most significant predictors and clarify specific mechanisms of NADPH oxidase activation. It was shown that kinetic parameters of response to opsonized zymosan (lag-time, response rate, amplitude, production of reactive species) were higher in blood of patients than controls. Amplitude and response rate were the most statistically significant predictors for distinguishing patients and controls at high glucose. It indicated NADPH oxidase activation was the target of hyperglycemia. Mathematical modeling showed hyperglycemia increased stability of NADPH oxidase complex, decreased synchronization of its assembling and elevated neutrophil capacity to phagocytosis in patients. Weak or no dependence of response kinetics on ionomycin concentration was shown in patients indicating changed Ca2+-dependent mechanism of NADPH oxidase activation. Hyperglycemia in type 2 diabetes causes disturbances in mechanisms of NADPH oxidase activation associated with both phagocytosis and the state of intracellular signaling systems, including Ca2+-dependent. We suggest that NADPH oxidase in blood granulocytes can be a promising target for clinical intervention improving management of diabetic complications associated with inflammation.

FSH, oxytocin and IGF-I regulate the expression of sirtuin 1 in porcine ovarian granulosa cells.

The involvement of the mTOR system/enzyme sirtuin 1 (SIRT1) intracellular signaling system in the control of ovarian functions and its role in mediating hormonal action on the ovary has been proposed, but this hypothesis should be supported by a demonstrated influence of hormones on mTOR/SIRT1. Therefore, the aim of our in vitro experiments was to examine the effect of the known hormonal regulators of ovarian functions, such as follicle-stimulating hormone (FSH), oxytocin (OT) and insulin-like growth factor I (IGF-I), on mTOR/SIRT1. The accumulation of SIRT1 in porcine ovarian granulosa cells cultured with and without these hormones (at doses of 1, 10 or 100 ng.ml-1) was evaluated using immunocytochemistry. It was observed that the addition of FSH (at 10 ng.ml-1 but not at 1 or 100 ng/ml) and OT (at all tested doses) increased the expression of SIRT1 in ovarian cells. In addition, 100 ng.ml-1, but not at 1 or 10 ng.ml-1, of IGF-I decreased SIRT1 accumulation. Our observations are the first demonstration that hormones can directly regulate the ovarian mTOR/SIRT1 system and that this system could mediate the action of hormonal regulators on the ovary.

Effect of Allocetra-OTS (off-the-shelf apoptotic cells) Therapy in Sepsis

Background & Aim Sepsis, which has been identified by the World Health Organization (WHO) as a global health priority, has no proven pharmacologic treatment other than appropriate antibiotic agents, fluids, vasopressors as needed, and possibly corticosteroids. Reported death rates among hospitalized patients are up to 45%. In sepsis, binding of either pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) among others, induces a complex intracellular signaling system with redundant and complementary activities. Allocetra-OTS (early apoptotic cells) was shown to have a beneficial effect on cytokine storms with downregulation of both anti- and pro-inflammatory cytokines and was prepared from a non-matched donor as described (Mevorach et al. BBMT, 2014) and 140 × 106 cells/kg I.V. in one or two doses were given within 24 hours of diagnosis to 10 patients with sepsis (ClinicalTrials.gov Identifier: NCT03925857).The primary aim was to determine the safety profile and the secondary aims were to determine the preliminary efficacy. Serum cytokine/chemokine and immune modulators measurement was performed sequentially using the Luminex MAGPIX system. Methods, Results & Conclusion All patients were with GCS of at least 13, verbal 5/5, due to the consent requirement. The average Acute Physiology and Chronic Health Evaluation (APACHE) II score was 12.3 (range 8–21) and the average SOFA score upon presentation was 3.4 (range 2–6) in treated patients. All patients fulfilled inclusion and exclusion criteria and met the 2016 definition of sepsis (Singer et al., 2016). All were hospitalized at admission in ICU and experienced a recovery from the septic condition and were discharged alive from the hospital following the resolution of sepsis and completed 28 days of follow-up. No SAEs were reported. No AEs were related to the investigational product. The predicted mortality by the APACHE II score was 18.1% and predicted probability of no death in these 10 patients was 0.15. The predicted mortality by SOFA score at presentation was > 10%, and in 36 matched-historical controls was 27.7%. The study population would have expected to have a mortality rate between 10–27%. Resolution of >20 pro- and anti-inflammatory cytokines was documented. Length of stay in ICU was significantly shorter (p The results of 0% mortality and rapid resolution of sepsis show no safety concerns with a potential preliminary efficacy.

Dysmetabolic and intracellular mechanisms of type 2 diabetes mellitus and colorectal cancer association

According to the results of modern research, patients with diabetes mellitus (DM) have an increased risk of oncological diseases, including colorectal cancer (CRC) that is one of the main reasons of mortality from malignant diseases among the population of Ukraine. Uncompensated diabetes is a reason of chronic metabolic stress, which causes defections of regulatory properties of intracellular signalling systems and activation of oncogenesis processes. Objective — to investigate the mechanisms of association between type 2 DM and colorectal cancer by determining the content of phospho-PRAS40, insulin and IGF-1. Materials and methods. 36 persons were examined. Patients were divided into groups: I — healthy (control group) (n = 10), II — patients with type 2DM (n = 10), III — patients with CRC without DM (n = 8), IV — patients with a combination CRC and type 2DM (n = 8). Using enzyme-linked immunosorbent assay the levels of insulin and IGF-1 in serum, and phospho-PRAS40 levels in peripheral blood mononuclear cells were determined. The level of glycosylated haemoglobin (HbA1c) was determined using ion exchange chromatography. Results and discussion. It was found that CRC occurs in people with obesity older than 60 years. Significant hyperinsulinemia and increased IGF-1 levels were found in the study groups compared to the control group (р < 0.05), with no gender differences (р > 0.05). Patients of group II with type 2 DM and group III with CRC had an increased level of phospho-PRAS40 compared to the control group (р < 0.05); in patients of group IV with combination of DM and CRC the level of phospho-PRAS40 was significantly lower than in the control group (р < 0.05). The level of HbA1c in patients with DM of the II and IV groups was more than 7.5 %, with no significant difference between these two groups (р > 0.05). Conclusions. Dysmetabolic disorders by type 2 DM,namely obesity, hyperinsulinemia, elevated IGF-1 levels, and hyperglycemia cause the development of molecular stress and syndrome of cancrophilia (a «cancer susceptibility») in patients with type 2 DM. The increased level of phosphorylated PRAS40 is a reflection of mTORC1 activation and a consequence of chronic metabolic stress caused by type 2 diabetes.

Moving towards a systems-based classification of innate immune-mediated diseases.

Autoinflammation as a distinct disease category was first reported in 1999 as a group of monogenic disorders characterized by recurrent episodes of systemic and organ-specific inflammation, known as periodic fever syndromes. Since this original description, the focus has shifted considerably to the inclusion of complex multifactorial conditions with an autoinflammatory basis. Furthermore, the boundaries of what are considered to be autoinflammatory disorders are constantly evolving and currently encompass elements of immunodeficiency and autoimmunity. Notable developments in the intervening 20 years include substantial progress in understanding how the different inflammasomes are activated, how infection is sensed by the innate immune system and how intracellular signalling systems are consequently activated and integrated with many different cellular functions in the autoinflammatory process. With these developments, the field of autoinflammation is moving from a gene-centric view of innate immune-mediated disease towards a systems-based concept, which describes how various convergent pathways, including pyrin and the actin cytoskeleton, protein misfolding and cellular stress, NF-κB dysregulation and interferon activation, contribute to the autoinflammatory process. The development and adoption of a systems-based concept of systemic autoinflammatory diseases is anticipated to have implications for the development of treatments that target specific components of the innate immune system.

The Quantum-Mechanical Sensitive Na/K Pump Is a Key Mechanism for the Metabolic Control of Neuronal Membrane Function

At present, there are relevant scientific materials on the cellular and molecular mechanisms of electrogenic Na/K pump function and structure, as well as on the potential- and ligand-activated ionic channels in the membrane. However, the role of electrogenic Na/K pump in regulation of semipermeable properties of cell membrane has not been elucidated yet, which is due to the fact that our knowledge about the biophysical properties of cell membrane is based on the conductive membrane theory of Hodgkin-Huxley-Katz, which is developed on internally perfused squid axon and lacks intracellular metabolism. Thus, the accumulated abundance of data on the role of G-proteins-dependent intracellular signaling system in regulation of Na/K pump activity and biophysical properties of cell membrane presumes fundamental revision of some statements of membrane theory. The aim of the present review is to briefly demonstrate our and literature data on cell hydration-induced auto-regulation of Na/K pump as well as on its role in metabolic control of semipermeable properties and excitability of neuronal membrane, which are omitted in the study of internally perfused squid axon.

Clinical significance of Janus kinase inhibitors in the therapy of rheumatoid arthritis: achievements and prospects

Significant successes in the use of biological agents (BA) have been achieved in the treatment of rheumatoid arthritis (RA); nonetheless, about 36% of patients cannot respond to therapy or achieve the expected effect. A new area in the treatment of RA is the use of Janus kinase (JAK) inhibitors, targeted synthetic disease-modifying anti-rheumatic drugs (chemical molecules with a molecular weight &lt;1 kDa for oral administration) that inhibit the activity of intracellular signaling systems. The authors consider the clinical achievements and prospects, which open the use of JAK inhibitors in the treatment of RA.

Gene expression in patients with abdominal aortic aneurysm - more than immunological mechanisms involved.

Abdominal aortic aneurysm (AAA) is a serious condition of unclear pathogenesis and progression. Two samples were collected from 48 patients during AAA surgery. One sample was collected from the aneurysm, the other from the aneurysm proximal neck where the tissue did not exhibit any aneurysmal changes. Subsequently, gene expression profiles using microarrays (Illumina) were compared in RNA extracted from the samples. Overall, 2,185 genes were found to be upregulated and 2,100 downregulated; from which 158 genes had a different expression with FDR<0.05 (False Discovery Rate) and FC>/=2 (Fold Change). Of this number, 115 genes were over-expressed and 43 under-expressed. The analysis of the gene list based on their biological pathways revealed that the regulation of inflammation was mediated by chemokine and cytokine signaling pathways, the integrin signaling pathway, and T and B cell activation. Moreover, a change was identified in the expression of genes involved in both intercellular and intracellular signaling systems.

A current understanding of drug-induced QT prolongation and its implications for anticancer therapy.

The QT interval, a global index of ventricular repolarization, varies among individuals and is influenced by diverse physiologic and pathophysiologic stimuli such as gender, age, heart rate, electrolyte concentrations, concomitant cardiac disease, and other diseases such as diabetes. Many drugs produce a small but reproducible effect on QT interval but in rare instances this is exaggerated and marked QT prolongation can provoke the polymorphic ventricular tachycardia 'torsades de pointes', which can cause syncope or sudden cardiac death. The generally accepted common mechanism whereby drugs prolong QT is block of a key repolarizing potassium current in heart, IKr, generated by expression of KCNH2, also known as HERG. Thus, evaluation of the potential that a new drug entity may cause torsades de pointes has relied on exposure of normal volunteers or patients to drug at usual and high concentrations, and on assessment of IKr block in vitro. More recent work, focusing on anticancer drugs with QT prolonging liability, is defining new pathways whereby drugs can prolong QT. Notably, the in vitro effects of some tyrosine kinase inhibitors to prolong cardiac action potentials (the cellular correlate of QT) can be rescued by intracellular phosphatidylinositol 3,4,5-trisphosphate, the downstream effector of phosphoinositide 3-kinase. This finding supports a role for inhibition of this enzyme, either directly or by inhibition of upstream kinases, to prolong QT through mechanisms that are being worked out, but include enhanced inward 'late' sodium current during the plateau of the action potential. The definition of non-IKr-dependent pathways to QT prolongation will be important for assessing risk, not only with anticancer therapies but also with other QT prolonging drugs and for generating a refined understanding how variable activity of intracellular signalling systems can modulate QT and associated arrhythmia risk.

Resveratrol directly affects ovarian cell sirtuin, proliferation, apoptosis, hormone release and response to follicle-stimulating hormone (FSH) and insulin-like growth factor I (IGF-I).

The objective of our study was to examine the influence of the plant polyphenol resveratrol (R) on the rapamycin signalling pathway (mammalian target of rapamycin; mTOR) and basic ovarian cell functions in mammalian targets, as well as on their response to the physiological hormonal stimulators follicle-stimulating hormone (FSH) and insulin-like growth factor I (IGF-I). Resveratrol was found to stimulate sirtuin 1 accumulation and apoptosis, inhibit proliferation, suppress P and promote T and E release. Alone, FSH promoted proliferation and had no effect on apoptosis, but had an inhibitory effect on these processes when combined with R. IGF-I alone stimulated proliferation and inhibited apoptosis and promoted P production but not that of T; however, in the presence of R, the addition of IGF-I switched from having an anti-apoptotic to a pro-apoptotic effect and stimulated T release, but it did not modify the effect of IGF-I on proliferation and P output. These observations: (1) demonstrate that R directly affects the basic ovarian cell functions of proliferation, apoptosis and steroidogenesis, (2) provide further evidence of the involvement of FSH and IGF-I in the regulation of these processes, (3) demonstrate the ability of R to prevent and even invert the effects of FSH and IGF-I on ovarian cells and (4) indicate that the effects of R may be mediated by the mTOR-sirtuin intracellular signalling system.

Age-Dependent Comparative Study of 4 Hz and 8 Hz EMF Exposure on Heart Muscle Tissue Hydration of Rats

Previously we have shown that 4 Hz and 8 Hz EMF exposures have depressing effect on the thermodynamic activity of water, which decreases peroxide formation. It has also been shown that 4 Hz EMF-treated physiological solution modulates the growth and development of microbes and heart muscle contractility, but 8 Hz EMF has pronounced inhibitory effect on bacterial growth and development. Therefore, in order to elucidate the possible mechanism of 4 Hz and 8 Hz EMF effects on heart muscle function, in the present work the effects of 4 Hz and 8 Hz EMF exposures on heart muscle tissue hydration, the sensitivity of 4 Hz and 8 Hz EMF-induced tissue hydration to 10−4 M ouabain (Na+/K+ pump inhibition) and 10−9 M ouabain (activation of intracellular signaling system) as well as the effects of 4 Hz and 8 Hz EMF exposures on the number of Na+/K+ pump units in the membrane of both young and old rats have been studied. The obtained data allow us to suggest that 8 Hz EMF exposure has more pronounced age-dependent modulation effect on tissue hydration of heart muscle than 4 Hz EMF and this effect is sensitive to Na+/K+ pump activity and intracellular signaling system.

GABA-Induced Intracellular Mg2+ Mobilization Integrates and Coordinates Cellular Information Processing for the Maturation of Neural Networks

Cells simultaneously utilize different intracellular signaling systems to process environmental information [1-4]. The magnesium ion (Mg2+) is recognized as a multitarget analog regulator that performs many roles, such as circadian timekeeping, due to the following properties: (1) it influences wide-ranging biological processes, (2) its concentration is tightly controlled within a narrow sub-millimolar range, and (3) its intracellular dynamics are slow and long lasting [5-11]; its regulatory manner is not all-or-none in contrast to the switch-like signal transduction by the well-established second messenger Ca2+ [12]. Recent studies, however, have reported another role for Mg2+ as a second messenger in immune cells-i.e., a switching system for cellular states [13, 14]. These multifaceted characteristics of Mg2+ raise the question of how Mg2+ processes information and how common its role is as a signaling molecule. We focused on the trophic effects of γ-aminobutyric acid (GABA) and its developmental transition, the molecular basis of which also remains poorly understood despite its evolutionarily well-conserved roles [15-19]. Here, we show that in neurons, GABAA receptor signaling, whose action is excitatory, triggers Mg2+ release from mitochondria specifically at early developmental stages, and that released Mg2+ stimulates the CREB and mTOR signaling pathways, thereby facilitating structural and functional maturation of neuralnetworks. We found that cytosolic Mg2+ fluctuations within physiological ranges is enough to crucially regulate ERK, CREB, and mTOR activities. Together, intracellular Mg2+ physiologically integrates and coordinates cellular information, and Mg2+ is a novel signal transducer for organizing neural networks.

Regulation of the Natriuretic Peptide Receptor 2 (Npr2) by Phosphorylation of Juxtamembrane Serine and Threonine Residues Is Essential for Bifurcation of Sensory Axons.

cGMP signaling elicited by activation of the transmembrane receptor guanylyl cyclase Npr2 (also known as guanylyl cyclase B) by the ligand CNP controls sensory axon bifurcation of DRG and cranial sensory ganglion (CSG) neurons entering the spinal cord or hindbrain, respectively. Previous studies have shown that Npr2 is phosphorylated on serine and threonine residues in its kinase homology domain (KHD). However, it is unknown whether phosphorylation of Npr2 is essential for axon bifurcation. Here, we generated a knock-in mouse line in which the seven regulatory serine and threonine residues in the KHD of Npr2 were substituted by alanine (Npr2-7A), resulting in a nonphosphorylatable enzyme. Real-time imaging of cGMP in DRG neurons with a genetically encoded fluorescent cGMP sensor or biochemical analysis of guanylyl cyclase activity in brain or lung tissue revealed the absence of CNP-induced cGMP generation in the Npr27A/7A mutant. Consequently, bifurcation of axons, but not collateral formation, from DRG or CSG in this mouse mutant was perturbed at embryonic and mature stages. In contrast, axon branching was normal in a mouse mutant in which constitutive phosphorylation of Npr2 is mimicked by a replacement of all of the seven serine and threonine sites by glutamic acid (Npr2-7E). Furthermore, we demonstrate that the Npr27A/7A mutation causes dwarfism as described for global Npr2 mutants. In conclusion, our in vivo studies provide strong evidence that phosphorylation of the seven serine and threonine residues in the KHD of Npr2 is an important regulatory element of Npr2-mediated cGMP signaling which affects physiological processes, such as axon bifurcation and bone growth.SIGNIFICANCE STATEMENT The branching of axons is a morphological hallmark of virtually all neurons. It allows an individual neuron to innervate different targets and to communicate with neurons located in different regions of the nervous system. The natriuretic peptide receptor 2 (Npr2), a transmembrane guanylyl cyclase, is essential for the initiation of bifurcation of sensory axons when entering the spinal cord or the hindbrain. By using two genetically engineered mouse lines, we show that phosphorylation of specific serine and threonine residues in juxtamembrane regions of Npr2 are required for its enzymatic activity and for axon bifurcation. These investigations might help to understand the regulation of Npr2 and its integration in intracellular signaling systems.

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.

Abstract 367: Quantitative Phosphoproteomic Profiling and Causal Pathway Analysis Reveal Novel Mediators and Mechanisms Supporting Glycoprotein VI (GPVI) Signaling and Platelet Function

Intracellular signaling systems associated with the platelet glycoprotein VI receptor (GPVI) are essential to hemostasis and also initiate atherothrombotic events in cardiovascular disease contexts. While many separable molecular entities linked to GPVI-mediated platelet activation have been characterized, a systemic understanding of GPVI signaling over the context of the entire platelet proteome remains far from complete. To test the hypothesis that specific, intact signaling systems downstream of GPVI regulate platelet function, we used a combination of tandem mass tag (TMT) labeling and high-resolution, multidimensional mass spectrometry and informatics tools to quantify and model protein phosphorylation events reproducibly measurable in platelets from healthy human subjects (n=5) in response to the GPVI specific agonist collagen-related peptide (CRP). Following CRP treatment, platelets rapidly regulated the phosphorylation state of 1004 serine, threonine and tyrosine residues on 542 proteins (fold change &gt; 1.5; false discovery rate &lt; 0.05). In addition to regulatory sites on kinases, phospholipases and other well-known targets, the majority of phosphorylation events following CRP stimulation occurred on proteins with uncharacterized roles in platelet function. CausalPath analysis of this data mapped 46 high confidence pathway relations, suggesting that Syk, PKCs and MAPKs ultimately drive the phosphorylation of several novel effectors specifically downstream of GPVI in platelet regulation, including CRMP-2, RAD23B and caldesmon. In addition to comprehensively mapping out known signaling relations while illuminating previously unrecognized regulatory mechanisms of platelet function around GPVI, our work provides a platform to generate novel, mechanistic and testable hypotheses from omics data sets for subsequent discovery-driven efforts to identify platelet-based therapeutic and biomarker targets relevant to cardiovascular disease risk, progression and mortality.

Extremely Low-Frequency Magnetic Fields and Redox-Responsive Pathways Linked to Cancer Drug Resistance: Insights from Co-Exposure-Based In Vitro Studies.

Electrical devices currently used in clinical practice and common household equipments generate extremely low-frequency magnetic fields (ELF-MF) that were classified by the International Agency for Research on Cancer as “possible carcinogenic.” Assuming that ELF-MF plays a role in the carcinogenic process without inducing direct genomic alterations, ELF-MF may be involved in the promotion or progression of cancers. In particular, ELF-MF-induced responses are suspected to activate redox-responsive intracellular signaling or detoxification scavenging systems. In fact, improved protection against oxidative stress and redox-active xenobiotics is thought to provide critical proliferative and survival advantage in tumors. On this basis, an ever-growing research activity worldwide is attempting to establish whether tumor cells may develop multidrug resistance through the activation of essential cytoprotective networks in the presence of ELF fields, and how this might trigger relevant changes in tumor phenotype. This review builds a framework around how the activity of redox-responsive mediators may be controlled by co-exposure to ELF-MF and reactive oxygen species-generating agents in tumor and cancer cells, in order to clarify whether and how such potential molecular targets could help to minimize or neutralize the functional interaction between ELF-MF and malignancies.

Endogenous Factors That Can Influence Skin pH.

Regulation of pH is one of the most complex mechanisms in human physiology. Indeed, the H+ ion concentration not only contributes to the establishment and maintenance of the body's homeostasis (by defining isohydria) but it also acts as an ionic, electric or osmotic driving force; provides optimum conditions for the proper functions of a plethora of molecules; behaves as an extra- and intracellular signaling system; exerts protective functions, and so on. The versatile role of pH requires delicate, well-orchestrated regulatory machineries that are controlled by a multitude of endogenous mechanisms - this is especially true for the skin whose pH is quite unique within the body. In this chapter, we summarize key endogenous factors and mechanisms that can influence the pH of the skin. Moreover, we highlight the significance of certain molecular systems (i.e., pH-sensing ionotropic and metabotropic receptors) that have recently emerged as potential "pH-regulated sensors and transducers," which are suggested to mediate the cellular effects of pH in various skin compartments and cells.

Dynamic Regulation of the Subunit Composition of BK Channels in Smooth Muscle

Ion channels in vascular smooth muscle cells control membrane potential, which is a major determinant of the intracellular Ca2+ concentration and thus vascular tone. Membrane potential is modulated by a complex collection of endogenous vasodilator and vasoconstrictor pathways that ultimately dictate regional vascular resistance, organ blood flow, and systemic arterial pressure. Membrane potential in vascular smooth muscle is dominated by multiple types of K+ channels including those regulated by Ca2+, voltage, and ATP.1 It is not surprising then that K+ channels in vascular smooth muscle have been studied extensively as targets in normal vasoregulatory pathways and as end-effectors gone awry in diseases. Most investigations to date have focused on traditional intracellular signaling systems (eg, cyclic nucleotides and their associated kinases2) and chronic changes in expression patterns (eg, downregulation of subunits3). Article, see p 650 In the present issue of Circulation Research , Zhai et al4 examine the novel hypothesis that endothelin-1 elicits vasoconstriction, in part, by rapidly altering the subunit composition of vascular smooth muscle K+ channels, thereby reducing their functional activity. The K+ channel under investigation is the large conductance Ca2+-activated K+ channel, known colloquially as BK (K+ channels of big conductance).1 The subunit composition of BK …

Expression of the JAK/STAT signaling pathway in the ligamentum flavum of patients with lumbar spinal canal stenosis.

Ligamentum flavum (LF) hypertrophy is an important cause of lumbar spinal canal stenosis (LSS), one of the most common spinal disorders in the elderly. Although many cytokines are reported to be associated with LF hypertrophy, the intracellular signaling system is rarely discussed. The purpose of this study was to identify the JAK/STAT signaling pathway and to examine the role of the JAK/STAT systems in the hypertrophied LF. The LF of 10 LSS patients was analyzed and the expression of JAK1, STAT3, phosphorylated (p)-STAT3, and actin was examined by Western blot analysis. The expression of p-STAT3 was also examined by immunostaining and its positive cell ratio was compared between LSS and non-LSS samples. We measured the thickness of the LF on magnetic resonance images and studied the relationship between its thickness and the expression of p-STAT3. JAK1, STAT3, and p-STAT3 were detected in almost all samples by Western blot analysis. Immunoreactivity against p-STAT3 was observed mainly in endothelial- and fibroblast-like cells. The expression of p-STAT3 was significantly higher in LSS than non-LSS samples; it was significantly stronger on the dorsal than the dural side of the LF and positively correlated with the thickness of the LF on the dorsal side. The JAK/STAT signaling pathway is positively correlated with the thickness of the LF. Our findings suggest that JAK1 and STAT3 molecules are involved in and regulate LF hypertrophy.

Hydrogen Peroxide and Polyamines Act as Double Edged Swords in Plant Abiotic Stress Responses.

The specific genetic changes through which plants adapt to the multitude of environmental stresses are possible because of the molecular regulations in the system. These intricate regulatory mechanisms once unveiled will surely raise interesting questions. Polyamines and hydrogen peroxide have been suggested to be important signaling molecules during biotic and abiotic stresses. Hydrogen peroxide plays a versatile role from orchestrating physiological processes to stress response. It helps to achieve acclimatization and tolerance to stress by coordinating intra-cellular and systemic signaling systems. Polyamines, on the other hand, are low molecular weight polycationic aliphatic amines, which have been implicated in various stress responses. It is quite interesting to note that both hydrogen peroxide and polyamines have a fine line of inter-relation between them since the catabolic pathways of the latter releases hydrogen peroxide. In this review we have tried to illustrate the roles and their multifaceted functions of these two important signaling molecules based on current literature. This review also highlights the fact that over accumulation of hydrogen peroxide and polyamines can be detrimental for plant cells leading to toxicity and pre-mature cell death.