Cross-talk of the renin-angiotensin and kallikrein-kinin systems

The renin-angiotensin (RAS) and kallikrein-kinin (KKS) systems play a key role in multiple physiological and pathophysiological conditions, including growth and development, inflammation, blood pressure regulation and control of renal function. In many instances, kinins and angiotensin II work together, e.g., during development, whereas they oppose each other's actions in the regulation of vascular tone and renal function. The RAS and KKS systems also interact at multiple levels, so that changes in the activity of one system greatly impact the activity of the other. The purpose of this brief review is to highlight recent knowledge regarding interactions at the cellular and molecular levels between the two systems, with an emphasis on the coordinate developmental regulation of these phylogenetically conserved vasoactive systems.     

Factor structure of the functional state of five- and six-year-old children

The following factors determining the functional state (FS) of the body of five- and six-year-old children (n = 155) have been identified during the research: parasympathetic regulation of FS (factor I); hemodynamic support of cognitive activity (factor II); efficiency of cognitive activity (factor III); nonspecific stability of the body (factor IV); sympathetic regulation of FS (factor V); general work capacity (factor VI). The systematic approach implemented in this study allowed consideration of the psychophysiological content of these factors. In general, the results of research demonstrate the existence of rather stable, qualitatively peculiar groups of variables characterizing different aspects of preschool children’s FS. There is a set of stable relationships between various elements of FS ensuring its integrity. The significant relationship between physical performance and FS aspects, such as productivity and efficiency of cognitive activity, sympathetic and parasympathetic regulation of physiological functions, and nonspecific stability of body to cold-related illnesses, suggests the possibility of purposeful influence on children’s FS during intense activity using adequate programs of physical exercise.     

Histoarchitectonics of the cholinergic innervation of the frog tongue

Acetylcholinesterase (AChE) activity was studied in dorsal tongue surface structures and in both tongue nerves (hypoglossal and glossopharyngeal) of frogs (Rana temporaria). AChE was found in nerve fibers of fungiform and filiform papillae, blood vessels, glandular ducts of tongue mucosa, both nerve fibers and also in the bodies of cholinergic neurons in subepithelial connective tissue and along the glossopharyngeal nerve. Their parasympathetic origin was suggested. The experiments with butirilthiocholin have revealed no activity of non-specific cholinesterases in the above structures. Possible role of cholinergic system in the regulation of tongue receptor function is discussed.     

Angiotensin II augmentation of tyrosine kinase activity in human adherent mononuclear cells

The relationship of angiotensin converting enzyme activity and angiotensin II to the inflammatory process in diseases such as sarcoidosis remains unclear. We hypothesize that granuloma macrophages regulate inflammation by release of angiotensin converting enzyme, which produces angiotensin II, and that angiotensin II in turn modulates monocyte/macrophage activity. Since tyrosine kinase catalyzes phosphorylation of tyrosine residues in proteins and is important in signal transduction and cellular activation, we further postulated that monocyte tyrosine kinases may play a role in the regulation of this process. Mononuclear cells from 11 healthy subjects were assayed for tyrosine kinase activity in the presence and absence of angiotensin II. In addition, tyrosine-specific phosphorylation of cellular proteins was also determined. Angiotensin II increased tyrosine kinase activity in a concentration-dependent manner. The maximal stimulation, which varied from 31 to 506%, was achieved following incubation of cells with 10(-4) M angiotensin II. Angiotensin II also increased the tyrosyl-phosphorylation of three proteins with molecular weights of 57, 62, and 63 kDa. We conclude that tyrosine kinase activity of adherent mononuclear cells and tyrosine phosphorylation of certain protein(s) may be involved in angiotensin II regulation of inflammatory processes.     

Parasympathetic Stimuli on Bronchial and Cardiovascular Systems in Humans

Background

It is not known whether parasympathetic outflow simultaneously acts on bronchial tone and cardiovascular system waxing and waning both systems in parallel, or, alternatively, whether the regulation is more dependent on local factors and therefore independent on each system. The aim of this study was to evaluate the simultaneous effect of different kinds of stimulations, all associated with parasympathetic activation, on bronchomotor tone and cardiovascular autonomic regulation.

Methods

Respiratory system resistance (Rrs, forced oscillation technique) and cardio-vascular activity (heart rate, oxygen saturation, tissue oxygenation index, blood pressure) were assessed in 13 volunteers at baseline and during a series of parasympathetic stimuli: O₂ inhalation, stimulation of the carotid sinus baroreceptors by neck suction, slow breathing, and inhalation of methacholine.

Results

Pure cholinergic stimuli, like O₂ inhalation and baroreceptors stimulation, caused an increase in Rrs and a reduction in heart rate and blood pressure. Slow breathing led to bradycardia and hypotension, without significant changes in Rrs. However slow breathing was associated with deep inhalations, and Rrs evaluated at the baseline lung volumes was significantly increased, suggesting that the large tidal volumes reversed the airways narrowing effect of parasympathetic activation. Finally inhaled methacholine caused marked airway narrowing, while the cardiovascular variables were unaffected, presumably because of the sympathetic activity triggered in response to hypoxemia.

Conclusions

All parasympathetic stimuli affected bronchial tone and moderately affected also the cardiovascular system. However the response differed depending on the nature of the stimulus. Slow breathing was associated with large tidal volumes that reversed the airways narrowing effect of parasympathetic activation.     

Effect of inhibition of the catalytic activity of cyclic AMP-dependent protein kinase on mitosis in PtK1 cells

Evidence has suggested that cyclic AMP, acting through activation of the type II cyclic AMP-dependent protein kinase, may play a role in the regulation of interphase and mitotic microtubules. In order to examine the potential role of the type II cAMP-dependent kinase during mitosis, dividing PtK1 cells were microinjected with two specific inhibitors of the catalytic activity of the type II kinase. These inhibitors were a specific protein inhibitor of cAMP-dependent protein kinase (PKI) and an affinity-purified polyclonal antiserum (anti-C) directed against the catalytic subunit of the kinase. Both have been shown previously to inhibit kinase activity in vitro. Microinjection of PKI during early- to mid-prophase significantly delayed the progression of the cells through mitosis, with the greatest delay occurring in metaphase. PKI injected during prometaphase also delayed progression through mitosis but to a lesser extent. Microinjection of anti-C during early- to mid-prophase also caused a significant delay in the completion of mitosis, with many cells becoming "hung up" in prometaphase. Anti-C injected during prometaphase had little effect on subsequent progression through mitosis. Microinjection of either anti-C or PKI during metaphase had no discernible effect. No effect on anaphase movement of chromosomes was observed with any treatment. These results provide further evidence that cAMP-dependent phosphorylation may be involved in the regulation of mitosis, although whether it acts directly through regulation of mitotic spindle microtubules is unclear.     

Blockade of Bradykinin receptors worsens the dystrophic phenotype of <Emphasis Type="Italic">mdx</Emphasis> mice: differential effects for B1 and B2 receptors

The Kallikrein Kinin System (KKS) is a vasoactive peptide system with known functions in the maintenance of tissue homeostasis, renal function and blood pressure. The main effector peptide of KKS is Bradykinin (BK). This ligand has two receptors: a constitutive B2 receptor (B2R), which has been suggested to have anti-fibrotic effects in renal and cardiac models of fibrosis; and the inducible B1 receptor (B1R), whose expression is induced by damage and inflammation. Inflammation and fibrosis are hallmarks of Duchenne muscular dystrophy (DMD), therefore we hypothesized that the KKS may play a role in this disease. To evaluate this hypothesis we used the mdx mouse a model for DMD. We blocked the endogenous activity of the KKS by treating mdx mice with B2R antagonist (HOE-140) or B1R antagonist (DesArgLeu⁸BK (DALBK)) for four weeks. Both antagonists increased damage, fibrosis, TGF-β and Smad-dependent signaling, CTGF/CCN-2 levels as well as the number of CD68 positive inflammatory cells. B2R blockade also reduced isolated muscle contraction force. These results indicate that the endogenous KKS has a protective role in the dystrophic muscle. The KKS may be a new target for future therapies to reduce inflammation and fibrosis in dystrophic muscle.     

Calmodulin regulates intracellular trafficking of epidermal growth factor receptor and the MAPK signaling pathway

The epidermal growth factor receptor (EGFR) is a member of the tyrosine kinase receptor family involved in signal transduction and the regulation of cellular proliferation and differentiation. It is also a calmodulin-binding protein. To examine the role of calmodulin in the regulation of EGFR, the effect of calmodulin antagonist, W-13, on the intracellular trafficking of EGFR and the MAPK signaling pathway was analyzed. W-13 did not alter the internalization of EGFR but inhibited its recycling and degradation, thus causing the accumulation of EGF and EGFR in enlarged early endosomal structures. In addition, we demonstrated that W-13 stimulated the tyrosine phosphorylation of EGFR and consequent recruitment of Shc adaptor protein with EGFR, presumably through inhibition of the calmodulin-dependent protein kinase II (CaM kinase II). W-13-mediated EGFR phosphorylation was blocked by metalloprotease inhibitor, BB94, indicating a possible involvement of shedding in this process. However, MAPK activity was decreased by W-13; dissection of this signaling pathway showed that W-13 specifically interferes with Raf-1 activity. These data are consistent with the regulation of EGFR by calmodulin at several steps of the receptor signaling and trafficking pathways.     

Changes in the local blood flows of the single kidney with partial impairment of the autonomic innervation

The changes of cortical and intramedullary blood flow of the remaining after nephrectomy kidney under the condition of guanethidine sympathectomy and continuous pharmacological blockade of parasympathetic mediation by atropine were studied in chronic experiments on Wistar line rats in dynamics at 4, 7, 15, 30, 60, 90 and 120 days. Decrease in cortical and increase of intramedullary peritubular blood flow were noted in both experimental series, that is both blockade of sympathetic and parasympathetic nerves after 15 days. The conclusion was made that blood flow redistribution is a universal mechanisms of single kidney adaptation to its neurogenic impairments.     

Protein kinases in human renal cell carcinoma and renal cortex. A comparison of isozyme distribution and of responsiveness to adenosine 3':5'-cyclic monophosphate.

Two major isozyme forms of cyclic AMP-dependent protein kinase (termed protein kinase I and II according to their order of elution from DEAE-cellulose) were resolved by DEAE-cellulose chromatography of extracts from human renal cortex and renal cell carcinoma. The ratio between protein kinase I and protein kinase II in carcinoma extracts was about twice that in extracts of renal cortex. The total soluble cyclic AMP-dependent protein kinase activity was similar in extracts from the normal and malignant tissue. Protein kinase isozymes prepared from renal cortex or carcinoma were highly dependent on cyclic AMP for activity under appropriate assay conditions, were activated to the same degree by various concentrations of cyclic AMP, and had similar affinity for the nucleotide, indicating that the mechanism for regulation of protein kinase activity by cyclic AMP was intact for the tumor kinases. The kinetics of endogenous phosphorylation of protein kinase II was similar for enzyme derived from normal or malignant tissue.     

Blood pressure regulation during cardiac autonomic blockade: effect of fitness

The purpose of this study was to determine the role of the autonomic nervous system's control of the heart in fitness-related differences in blood pressure regulation. The cardiovascular responses to progressive lower-body negative pressure (LBNP) were studied during unblocked (control) and full blockade (experimental) conditions in 10 endurance-trained (T) and 10 untrained (UT) men, aged 20-31 yr. The experimental conditions included beta 1-adrenergic blockade (metoprolol tartrate), parasympathetic blockade (atropine sulfate), or complete blockade (metoprolol and atropine). Heart rate, blood pressure, forearm blood flow, and cardiac output were measured at rest and -16 and -40 Torr LBNP. Forearm vascular resistance, peripheral vascular resistance, and stroke volume were calculated from these measurements at each stage of LBNP. Blood pressure was maintained, primarily by augmented vasoconstriction, equally in T and UT subjects during complete and atropine blockade. The fall in systolic and mean pressure from 0 to -40 Torr was greater (P less than 0.05) in the T subjects during the unblocked and metoprolol blockade conditions. This reduced blood pressure control during unblocked condition was attributable to attenuated vaso-constrictor and chronotropic responses in the T subjects. We hypothesize that an autonomic imbalance (elevated base-line parasympathetic activity) in highly trained subjects restricts reflex cardiac responses, which accompanied by an attenuated vasoconstrictor response, results in attenuated blood pressure control during a steady-state hypotensive stress.     

Mutation of the casein kinase II phosphorylation site abolishes the anti-proliferative activity of p53.

The p53 tumour suppressor protein is phosphorylated by several protein kinases, including casein kinase II. In order to understand the functional significance of phosphorylation by casein kinase II, we have introduced mutations at serine 386 in mouse p53, the residue phosphorylated by this kinase, and investigated their effects on the ability of p53 to arrest cell growth. Replacement of serine 386 by alanine led to loss of growth suppressor activity, while aspartic acid at this position partially retained suppressor function. These data suggest that the anti-proliferative activity of p53 is activated by phosphorylation at serine 386, and establish a direct link between the covalent modification of a growth suppressor protein and regulation of its activity in mammalian cells.     

Ca2+/calmodulin-dependent kinase II phosphorylates the epidermal growth factor receptor on multiple sites in the cytoplasmic tail and serine 744 within the kinase domain to regulate signal generation.

Down-regulation of receptor tyrosine kinase activity plays an essential role in coordinating and controlling cellular growth/differentiation. Ca2+/calmodulin-dependent kinase II (CaM kinase II)-mediated phosphorylation of threonine 1172 in the cytoplasmic tail of HER2/c-erbB2 can modulate tyrosine kinase activity and consensus phosphorylation sites are also found at serines 1046/1047 in the structurally related epidermal growth factor receptor (EGFR). We show that serines 1046/1047 are sites for CaM kinase II phosphorylation, although there is a preference for serine 1047, which resides within the consensus -R-X-X-S-. In addition, we have identified major phosphorylation sites at serine 1142 and serine 1057, which lie within a novel -S-X-D- consensus. Mutation of serines 1046/1047 in full-length EGFR enhanced both fibroblast transformation and tyrosine autokinase activity that was significantly potentiated by additional mutation of serines 1057 and 1142. A single CaM kinase II site was also identified at serine 744 within sub-kinase domain III, and autokinase activity was significantly affected by mutation of this serine to an aspartic acid making this site appear constitutively phosphorylated. We have addressed the mechanism by which CaM kinase II phosphorylation of the EGFR might regulate receptor autokinase activity and show that this modification can hinder association of the cytoplasmic tail with the kinase domain to prevent an enzyme-substrate interaction. We postulate that the location and greater number of CaM kinase II phosphorylation sites in the EGFR compared with HER-2/c-erbB2, leading to differential regulation of autokinase activity, contributes to differences in the strength of downstream signaling events and may explain the higher relative transforming potential of HER-2/cerbB2.     

Characterization of the kallikrein-kinin system during the bovine ovulation process

The kallikrein–kinin system (KKS) has been described as an important mediator of physiologic processes. Kallikreins use kininogen (KNG) as substrate to generate bradykinin, the main active peptide of the KKS that acts through two types of receptors, the B₁R and the B₂R. The goal of this study was to characterize some components of the KKS in different compartments of the ovary during the bovine ovulation process. The KNG, B₁R and B₂R mRNA expression patterns were assessed in theca and granulosa cells, as well as the bradykinin concentration and kallikrein-like activity in follicular fluid of bovine periovulatory follicles. To obtain a periovulatory follicle (≥12 mm), twenty-seven cows were submitted to estrus synchronization protocol and ovariectomized by colpotomy at 0, 3, 6, 12 or 24 h after a GnRH-analog injection (gonadorelin; 100 μg, IM). Follicular fluid was aspirated for enzymatic assays while granulosa and theca cells were harvested for mRNA analysis. The mRNA expressions in follicular cells were evaluated by real-time RT-PCR and data representation related to the cyclophilin housekeeping gene. The bradykinin concentration and kallikrein-like activity were measured in follicular fluid by enzymatic immunoassay and selective substrate cleavage, respectively. The B₂R expression in theca cells and B₁R expression in theca and granulosa cells showed different profiles during the periovulatory period (P < 0.05). The bradykinin concentration and kallikrein-like activity in the follicular fluid were different (P < 0.05) due to the time during the ovulation process. KNG mRNA expression was similar for both follicular cell types (P > 0.05). Taken together, these results provide an important characterization of the presence and possible KKS regulation during the bovine ovulation.     

Induction and regulation of casein kinase II during B lymphocyte activation.

This study evaluates the regulation of casein kinase II (CK II) activity in resting B cells induced to enter the cell cycle. The induction of B cell cycle progression PMA and ionomycin results in an oscillatory expression of CK II. This kinase activity is also elicited after direct physical interaction between B cells and activated, fixed Th cells, indicating that the increase seen in CK II activity is probably associated with the delivery of the competence-inducing signal to resting B cells. The selective inhibition of ornithine decarboxylase (ODC), the rate-limiting enzyme for polyamine biosynthesis, during PMA and ionomycin-induction of B cell cycle progression, inhibits the expression of CK II activity. The addition of polyamines to cytosolic preparations recovered from cells in which ODC is inhibited results in the appearance of CK II activity, showing that the ODC inhibitor does not directly inhibit the kinase. The treatment of B cells with cycloheximide results in the appearance of CK II activity within 15 min, and this induction is partially explainable by a cycloheximide-elicited increase in cellular levels of polyamines. The artificial elevation of cellular levels of cAMP simultaneous with the addition of PMA and ionomycin results in a 150 to 200% increase in detectable CK II levels, suggesting that the cAMP-dependent signaling cascade may participate during the early regulation of CK II. In contrast, the inhibition of protein kinase C does not adversely influence the early expression of CK II, while actually enhancing kinase activity by 18 h poststimulation.     

The kallikrein-kinin and the renin-angiotensin systems have a multilayered interaction

Understanding the physiological role of the plasma kallikrein-kinin system (KKS) has been hampered by not knowing how the proteins of this proteolytic system, when assembled in the intravascular compartment, become activated under physiological conditions. Recent studies indicate that the enzyme prolylcarboxypeptidase, an ANG II inactivating enzyme, is a prekallikrein activator. The ability of prolylcarboxypeptidase to act in the KKS and the renin-angiotensin system (RAS) indicates a novel interaction between these two systems. This interaction, along with the roles of angiotensin converting enzyme, cross talk between bradykinin and angiotensin-(1-7) action, and the opposite effects of activation of the ANG II receptors 1 and 2 support a hypothesis that the plasma KKS counterbalances the RAS. This review examines the interaction and cross talk between these two protein systems. This analysis suggests that there is a multilayered interaction between these two systems that are important for a wide array of physiological functions.     

Alternating lateralization of plasma catecholamines and nasal patency in humans

The nose receives both sympathetic and parasympathetic innervation that is manifested by the alternating dominance of sympathetic activity on one side with concurrent parasympathetic dominance on the other. This ultradian rhythm of autonomic function, known as the nasal cycle, averages 2-3 hours in length. Previous experiments have shown that the nasal cycle is correlated in an inversely coupled fashion to the alternating dominance of activity in the two cerebral hemispheres, suggesting a common mechanism of regulation. Here we show that there is an alternation in catecholamine levels of blood drawn from anticubital veins that may also correlate with the nasal cycle. Radioenzymatic measurement of norepinephrine, epinephrine, and dopamine in blood sampled simultaneously from both arms every 7.5 minutes for periods of 3-6 hours demonstrated alternating high levels of catecholamine in one of the two arms. This alternating lateralization of neurotransmitters was observed in 7 out of 7 experiments using resting human male subjects. The ratio of norepinephrine in the two arms also parallels the pattern of airflow in the nasal cycle. This study suggests that the autonomic nervous system may alternate in activity through paired structures.     

Casein kinase II activity in the brain of an insect,Acheta domesticus: Characterization and hormonal regulation

This study documented casein kinase II (CK II) activity in Acheta domesticus brain using specific antibodies and its regulation by polyamines. In control animals a transient decrease in CK II activity at day 3 after imaginal moult was observed in the brain but not in the fat body. If deprived of ecdysone by ovariectomy a different pattern was observed, with CK II activity being significantly higher on days 3 and 4 after emergence. After ecdysone injection in ovariectomized females, CK II activity decreased to levels similar to those in controls. The implications of ecdysone regulation of brain CK II activity are discussed. © 1997 Wiley-Liss, Inc.