Molecular networks of brain and immunity

Immunosenescence as a convergence pathway in neurodegeneration

Immunity refers to the body's defense mechanism to protect itself against illness or to produce antibodies against pathogens. Senescence is a cellular phenomenon that integrates a sustainable growth restriction, other phenotypic abnormalities and including a pro-inflammatory secretome. It is highly involved in regulating developmental stages, tissue homeostasis, and tumor proliferation monitoring. Contemporary experimental reports imply that abolition of senescent cells employing evolved genetic and therapeutic approaches augment the chances of survival and boosts the health span of an individual. Immunosenescence is considered as a process in which dysfunction of the immune system occurs with aging and greatly includes remodeling of lymphoid organs. This in turn causes fluctuations in the immune function of the elderly that has strict relation with the expansion of autoimmune diseases, infections, malignant tumors and neurodegenerative disorders. The interaction of the nervous and immune systems during aging is marked by bi-directional influence and mutual correlation of variations. The enhanced systemic inflammatory condition in the elderly, and the neuronal immune cell activity can be modulated by inflamm-aging and peripheral immunosenescence resulting in chronic low-grade inflammatory processes in the central Nervous system known as neuro-inflammaging. For example, glia excitation by cytokines and glia pro-inflammatory productions contribute significantly to memory injury as well as in acute systemic inflammation, which is associated with high levels of Tumor necrosis factor -α and a rise in cognitive decline. In recent years its role in the pathology of Alzheimer's disease has caught research interest to a large extent. This article reviews the connection concerning the immune and nervous systems and highlights how immunosenescence and inflamm-aging can affect neurodegenerative disorders.

Reduced Immunosenescence of Peripheral Blood T Cells in Parkinson's Disease with CMV Infection Background

Immunosenescence is a process of remodeling the immune system under the influence of chronic inflammation during aging. Parkinson’s disease (PD) is a common age-associated neurodegenerative disorder and is frequently accompanied by neuroinflammation. On the other hand, cytomegalovirus (CMV), one of the most spread infections in humans, may induce chronic inflammation which contributes to immunosenescence, differentiation and the inflation of T cells and NK cells. Currently, there is no clear understanding of immunosenescence severity in PD patients infected with CMV. In this study, we analyzed differentiation stages and immunosenescence characteristics of T cells and NK cells in 31 patients with mild and moderate PD severity, 33 age-matched and 30 young healthy donors. The PD patients were 100% CMV-seropositive compared to 76% age-matched and 73% young CMV-infected healthy donors. The proportion of effector memory T cells re-expressing CD45RA, CD57⁺CD56⁻ T cells and CD57⁺CD56⁺ T cells was significantly reduced in PD patients compared with CMV-seropositive age-matched healthy individuals. The CD57⁺CD56⁻ T cell proportion in PD patients was similar to that of CMV-seropositive young healthy donors. Thus, PD is characterized by reduced peripheral blood T cell immunosenescence, even against the background of CMV infection.

Imipramine and Venlafaxine Differentially Affect Primary Glial Cultures of Prenatally Stressed Rats

Here, we examine the effects of prenatal administration of two antidepressants—imipramine (IMI) and venlafaxine (VEN)—on morphology and activity of a primary glial culture. Microglia are targeted by antidepressants used for antenatal depression and are important regulators of central nervous system development. In this study, female Wistar rats were assigned to one of four groups: a control group that received water ad libitum (1), and groups that received additionally once daily either water (2), IMI (10 mg/kg) (3), or VEN (20 mg/kg) (4) by oral gavage from gestation day 7 to 22. Oral gavage administration induced prenatal stress. Cell cultures were obtained from the brains of 1-day-old pups. Prenatal stress caused a disturbance of sensorimotor function in pups. Prenatal stress also produced alterations in the glial cultures, specifically, an increased percentage of microglia in the mixed glial cultures and an increased percentage of dead cells. Moreover, increased levels of IL1-β, TNF-α, NO, and an increased expression of CX3CR1 mRNA were found in microglia. However, the ratio of Bax/Bcl2 mRNA was reduced. Prenatal stress increased the vulnerability of microglia to lipopolysaccharide (LPS). The mixed glial culture derived from pups exposed to IMI showed greater morphological changes and the highest percentage of microglia. Microglia were characterized by the largest increase in the production of pro-inflammatory cytokines and NO, and the greatest reduction in the expression of CX3CR1 mRNA. Exposure to IMI reduced the effects of LPS on IL-1β production and Bax/Bcl2 mRNA, and exacerbated the effects of LPS on CX3CR1 mRNA expression. Prenatal administration of VEN induced protective effects on microglia, as measured by all studied parameters. Taken together, our data suggest that, by disturbing microglia function, exposure to even mild forms of chronic prenatal stress may predispose individuals to psychiatric or neurodevelopmental disorders. These data also indicate that chronic mild stress sensitizes microglia to immune challenges, which may lead to enhanced neuronal damage in the embryonic brain. The observed detrimental effects of IMI on microglial activity under conditions of prenatal stress may help to explain the teratogenic effects of IMI reported in the literature.

Efficacy of Celecoxib Adjunct Treatment on Bipolar Disorder: Systematic Review and Meta-Analysis

BACKGROUND

Bipolar Disorder (BD) is a psychiatric disorder characterized by mood disturbances. The pathophysiology of BD is still poorly understood. In the last years, research studies focused on the role of inflammation in BD.

OBJECTIVE

Performed a systematic review and meta-analysis to evaluate the potential effect of the cyclo- oxygenases (Cox)-2 inhibitor Celecoxib adjunct treatment in BD through randomized controlled trials (RCT).

METHODS

A search on the electronic databases was proceeded, on MEDLINE, EMBASE, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), Biomed Central, Web of Science, IBECS, LILACS, PsycINFO, Congress Abstracts, and Grey literature (Google Scholar and the British Library) for studies published from January 1990 to February 2018. A search strategy was developed using the terms: "Bipolar disorder" or "Bipolar mania" or "Bipolar depression" or "Bipolar mixed" or "Bipolar euthymic" and "Celecoxib" or "Cyclooxygenase-2 inhibitors" or "Cox-2 inhibitors" as text words and Medical Subject Headings (i.e., MeSH and EMTREE) and searched. The therapeutic effects of adjunctive treatment with Celecoxib were analyzed. The meta-analysis was performed including the results of the Young Mania Rating Scale (YMRS) at the end of RCT.

RESULTS

Three primary studies were included in the systematic review, with a total of 121 patients. The meta-analysis showed a significant effect on the YMRS scores from patients with BD who used Celecoxib adjuvant treatment in comparison to placebo.

CONCLUSION

The systematic review suggests that adjuvant treatment with Celecoxib improves the response of major treatments in patients with BD when compared with adjuvant placebo treatment. Systematic Review Registration Number: The review protocol was registered at PROSPERO (registration number: CRD42017067635); in June 06 2017.

The Continuum of Aging and Age-Related Diseases: Common Mechanisms but Different Rates

Geroscience, the new interdisciplinary field that aims to understand the relationship between aging and chronic age-related diseases (ARDs) and geriatric syndromes (GSs), is based on epidemiological evidence and experimental data that aging is the major risk factor for such pathologies and assumes that aging and ARDs/GSs share a common set of basic biological mechanisms. A consequence is that the primary target of medicine is to combat aging instead of any single ARD/GSs one by one, as favored by the fragmentation into hundreds of specialties and sub-specialties. If the same molecular and cellular mechanisms underpin both aging and ARDs/GSs, a major question emerges: which is the difference, if any, between aging and ARDs/GSs? The hypothesis that ARDs and GSs such as frailty can be conceptualized as accelerated aging will be discussed by analyzing in particular frailty, sarcopenia, chronic obstructive pulmonary disease, cancer, neurodegenerative diseases such as Alzheimer and Parkinson as well as Down syndrome as an example of progeroid syndrome. According to this integrated view, aging and ARDs/GSs become part of a continuum where precise boundaries do not exist and the two extremes are represented by centenarians, who largely avoided or postponed most ARDs/GSs and are characterized by decelerated aging, and patients who suffered one or more severe ARDs in their 60s, 70s, and 80s and show signs of accelerated aging, respectively. In between these two extremes, there is a continuum of intermediate trajectories representing a sort of gray area. Thus, clinically different, classical ARDs/GSs are, indeed, the result of peculiar combinations of alterations regarding the same, limited set of basic mechanisms shared with the aging process. Whether an individual will follow a trajectory of accelerated or decelerated aging will depend on his/her genetic background interacting lifelong with environmental and lifestyle factors. If ARDs and GSs are manifestations of accelerated aging, it is urgent to identify markers capable of distinguishing between biological and chronological age to identify subjects at higher risk of developing ARDs and GSs. To this aim, we propose the use of DNA methylation, N-glycans profiling, and gut microbiota composition to complement the available disease-specific markers.

Direct binding of Toll-like receptor 4 to ionotropic glutamate receptor N-methyl-D-aspartate subunit 1 induced by lipopolysaccharide in microglial cells N9 and EOC 20

Microglia, the primary immune cells in the brain, are the predominant cells regulating inflammation-mediated neuronal damage. In response to immunological challenges, such as lipopolysaccharide (LPS), microglia are activated and the inflammatory process is subsequently initiated. The aim of the present study was to determine whether LPS induces interactions between the Toll-like receptor 4 (TLR4) and the ionotropic glutamate receptor N-methyl-D-aspartate subunit 1 (GluN1) in N9 and EOC 20 microglial cells. Immunocytochemistry demonstrated co-localization of TLR4 and GluN1 in response to LPS, and the direct binding of TLR4 and GluN1 was further validated by antibody-based Fluorescence Resonance Energy Transfer technology. Inhibition of the group I metabotropic glutamate receptor 5 with its selective antagonist, MTEP, abolished LPS-induced direct binding of TLR4 to GluN1. Therefore, these data demonstrated that GluN1 and TLR4 act reciprocally in response to LPS in N9 and EOC 20 microglial cells.

Similarity and Differences in Inflammation-Related Characteristics of the Peripheral Immune System of Patients with Parkinson's and Alzheimer's Diseases

Parkinson's disease (PD) and Alzheimer's disease (AD) are the most common age-related neurodegenerative disorders. Both diseases are characterized by chronic inflammation in the brain-neuroinflammation. The first signs of PD and AD are most often manifested in old age, in which the immune system is usually characterized by chronic inflammation, so-called "inflammaging" In recent years, there is growing evidence that pathogenesis of these diseases is connected with both regional and peripheral immune processes. Currently, the association of clinical signs of PD and AD with different characteristics of patient immune status is actively being researched. In this mini-review we compare the association of PD and AD alterations of a number of immune system parameters connected with the process of inflammation.

Inhibitory effect of the Pseudobrickellia brasiliensis (Spreng) R.M. King & H. Rob. aqueous extract on human lymphocyte proliferation and IFN-γ and TNF-α production in vitro

Pseudobrickellia brasiliensis (Asteraceae) is a plant commonly known as arnica-do-campo and belongs to the native flora of the Brazilian Cerrado. The alcoholic extract of the plant has been used as an anti-inflammatory agent in folk medicine, but the biological mechanism of action has not been elucidated. The present study evaluated the composition of P. brasiliensis aqueous extract and its effects on pro-inflammatory cytokine production and lymphocyte proliferation. The extracts were prepared by sequential maceration of P. brasiliensis leaves in ethanol, ethyl acetate, and water. Extract cytotoxicity was evaluated by trypan blue exclusion assay, and apoptosis and necrosis were measured by staining with annexin V-FITC and propidium iodide. The ethanolic (ETA) and acetate (ACE) extracts showed cytotoxic effects. The aqueous extract (AQU) was not cytotoxic. Peripheral blood mononuclear cells stimulated with phorbol myristate acetate and ionomycin and treated with AQU (100 μg/mL) showed reduced interferon (IFN)-γ and tumor necrosis factor (TNF)-α expression. AQU also inhibited lymphocyte proliferative response after nonspecific stimulation with phytohemagglutinin. The aqueous extract was analyzed by liquid chromatography coupled with photodiode array detection and mass spectrometry. Quinic acid and its derivatives 5-caffeoylquinic acid and 3,5-dicaffeoylquinic acid, as well as the flavonoids luteolin and luteolin dihexoside, were detected. All these compounds are known to exhibit anti-inflammatory activity. Taken together, these findings demonstrate that P. brasiliensis aqueous extract can inhibit the pro-inflammatory cytokine production and proliferative response of lymphocytes. These effects may be related to the presence of chemical substances with anti-inflammatory actions previously reported in scientific literature.

Different influence of antipsychotics on the balance between pro- and anti-inflammatory cytokines depends on glia activation: An in vitro study

The microglial hypothesis of schizophrenia suggests that its neuropathology is closely associated with neuroinflammation manifested, inter alia, by an increased expression of cytokines. However, clinical investigations imply that schizophrenia is a heterogeneous disease and in some groups of patients the activated inflammatory process does not contribute to the disease-associated impairment of brain function. Clinical studies revealed also an equivocal impact of antipsychotics on peripheral and CSF cytokines, whereas experimental research performed on the stimulated glia cultures showed their inhibitory effect on pro-inflammatory cytokine levels. In the present study, the effect of chlorpromazine, haloperidol and risperidone (0.5, 5 or 10μM) on production of pro-inflammatory cytokines IL-1β and TNF-α and anti-inflammatory IL-10 was investigated in the unstimulated and lipopolysaccharide-stimulated primary rat mixed glial cell cultures. In the unstimulated cultures, haloperidol at all applied concentrations, risperidone at 5, 10μM and chlorpromazine at 10μM increased IL-10 levels in the culture supernatants without a significant influence on IL-1β or TNF-α levels, and all drugs applied at 10μM induced a robust increase in IL-10 mRNA expression. Under strong inflammatory activation, haloperidol and risperidone at all concentrations reduced production of both pro-inflammatory cytokines, without adverse effects on IL-10 expression when used at 10μM. Chlorpromazine at all concentrations diminished the production of three cytokines and did not induce anti-inflammatory effect. These results suggest that dependently on glia activation antipsychotics via different mechanisms may induce anti-inflammatory effect and that this activity is not common for all drugs under conditions of strong glia activation.

[Protective Effects of Myelopeptides in Neuroblastoma C-1300 Cell Culture]

The effects of bone marrow regulatory peptides--myelopeptides 1-6--in mouse neuroblastoma C-1300 were studied. Cultivation in presence of myelopeptides stimulated morphological differentiation of neuroblasts. Neuroprotective abilities of myelopeptides were shown on the models of morphine toxity and oxygen-glucose deprivation in neuroblastoma cell culture.

Cell-cell nanotubes: Tunneling through several types of synapses

Nanotube can be generally seen as a nanoscale cylindrical structure. Membrane (or tunneling) nanotube (TNT) is a cytoplasmic tunnel between two cells. Such direct cell-cell channel is used for a physical transport of biochemical cargo, whereas nanotubular networks between cells may be a novel principle of communicative and integrative biology. Recently, TNTs and their networks were discovered in plant cells and then they were reported also in animal cells. Just the reverse, a notion of plant synapse has been also proposed only recently, long after the corresponding notion of neuronal synapse in animals. However, both TNTs and synapses seem to be closely related and evolutionary conserved structures through different types of cells. Accordingly, this mini-review aims to demonstrate that TNTs may represent one of the deep functional similarities between neuronal, immune, viral and plant synapses.

The role of psychoneuroimmunology in personalized and systems medicine

Psychoneuroimmunology (PNI) may provide the scientific basis for personalized and systems medicine. The exploration of the extensive interactions among psychological and behavioral factors, the nervous system, the immune system, and the endocrine system may help understand the mechanisms underlying health, wellness, and diseases. PNI theories based on systems biology methodologies may contribute to the identification of patient patterns for establishing psychological and physiological profiles for personalized medicine. A biopsychosocial model will help elucidate the systemic interrelationships between psychosocial and bio-physiological factors for the development of systems medicine. Many evidences have supported the close relationships between stress, depression, inflammation, and disorders including obesity, cardiovascular disease, diabetes, arthritis, skin diseases, infectious diseases, and sleep disorders. As inflammation is a critical connection among different diseases, the elucidation of the associations may contribute to the findings of systemic therapeutic targets. With the understanding of the translational implications of PNI, integrative interventions in multiple dimensions can be applied to modulate stress responses and promote healthier behaviors. These interventions include combination drug therapies, diets, nutritional supplements, meditation, and other behavioral and mind-body strategies.

Translational implications of inflammatory biomarkers and cytokine networks in psychoneuroimmunology

Developments in psychoneuroimmunology (PNI) need to be translated into personalized medicine to achieve better clinical outcomes. One of the most critical steps in this translational process is to identify systemic biomarkers for better diagnosis and treatment. Applications of systems biology approaches in PNI would enable the insights into the correlations among various systems and different levels for the identification of the basic elements of the psychophysiological framework. Among the potential PNI biomarkers, inflammatory markers deserve special attention as they play a pivotal role linking various health conditions and disorders. The elucidation of inflammatory markers, cytokine networks, and immune-brain-behavior interactions may help establish PNI profiles for the identification of potential targets for personalized interventions in at risk populations. The understanding of the general systemic pathways among different disorders may contribute to the transition from the disease-centered medicine to patient-centered medicine. Integrative strategies targeting these factors and pathways would be useful for the prevention and treatment of a spectrum of diseases that share the common links. Examples of the translational implications of potential PNI biomarkers and networks in diseases including depression, Alzheimer's disease, obesity, cardiovascular disease, stroke, and HIV are discussed in details.

In Silico Augmentation of the Drug Development Pipeline: Examples from the study of Acute Inflammation

The clinical translation of promising basic biomedical findings, whether derived from reductionist studies in academic laboratories or as the product of extensive high-throughput and -content screens in the biotechnology and pharmaceutical industries, has reached a period of stagnation in which ever higher research and development costs are yielding ever fewer new drugs. Systems biology and computational modeling have been touted as potential avenues by which to break through this logjam. However, few mechanistic computational approaches are utilized in a manner that is fully cognizant of the inherent clinical realities in which the drugs developed through this ostensibly rational process will be ultimately used. In this article, we present a Translational Systems Biology approach to inflammation. This approach is based on the use of mechanistic computational modeling centered on inherent clinical applicability, namely that a unified suite of models can be applied to generate in silico clinical trials, individualized computational models as tools for personalized medicine, and rational drug and device design based on disease mechanism.

Translational systems approaches to the biology of inflammation and healing

Inflammation is a complex, non-linear process central to many of the diseases that affect both developed and emerging nations. A systems-based understanding of inflammation, coupled to translational applications, is therefore necessary for efficient development of drugs and devices, for streamlining analyses at the level of populations, and for the implementation of personalized medicine. We have carried out an iterative and ongoing program of literature analysis, generation of prospective data, data analysis, and computational modeling in various experimental and clinical inflammatory disease settings. These simulations have been used to gain basic insights into the inflammatory response under baseline, gene-knockout, and drug-treated experimental animals for in silico studies associated with the clinical settings of sepsis, trauma, acute liver failure, and wound healing to create patient-specific simulations in polytrauma, traumatic brain injury, and vocal fold inflammation; and to gain insight into host-pathogen interactions in malaria, necrotizing enterocolitis, and sepsis. These simulations have converged with other systems biology approaches (e.g., functional genomics) to aid in the design of new drugs or devices geared towards modulating inflammation. Since they include both circulating and tissue-level inflammatory mediators, these simulations transcend typical cytokine networks by associating inflammatory processes with tissue/organ impacts via tissue damage/dysfunction. This framework has now allowed us to suggest how to modulate acute inflammation in a rational, individually optimized fashion. This plethora of computational and intertwined experimental/engineering approaches is the cornerstone of Translational Systems Biology approaches for inflammatory diseases.

Effects of psychological stress and fluoxetine on development of oral candidiasis in rats

Psychological stress has been found to suppress cell-mediated immune responses that are important for limiting the proliferation of Candida albicans. Fluoxetine has been observed to reduce negative consequences of stress on the immune system in experimental and clinical models, but there are no data on its effects on oral candidiasis. We designed experiments to evaluate the effects of fluoxetine on the development of oral candidiasis in Sprague-Dawley rats exposed to a chronic auditory stressor. Animals were submitted to surgical hyposalivation in order to facilitate the establishment and persistence of C. albicans infection. Stress application and treatment with drugs (placebo or fluoxetine) were initiated 7 days before C. albicans inoculation and lasted until the end of the experiments, on day 15 postinoculation. Establishment of C. albicans infection was evaluated on days 2 and 15 after inoculation. Tissue injury was determined by the quantification of the number and type (normal or abnormal) of papillae on the dorsal tongue per microscopic field. A semiquantitative scale was devised to assess the degree of colonization of the epithelium by fungal hyphae. Our results showed that stress exacerbates C. albicans infection in the tongues of rats. Significant increases in Candida counts, the percentage of the tongue's surface covered with clinical lesions, the percentage of abnormal papillae, and the colonization of the epithelium by hyphae were found in stressed rats compared to the nonstressed ones. Treatment with fluoxetine significantly reversed these adverse effects of stress. Besides the psychopharmacological properties of fluoxetine against stress, it has consequences for Candida infection.

Mathematical modeling of the capillary-like pattern generated by adrenomedullin-treated human vascular endothelial cells in vitro

A recently proposed approach was used to model the self-organization into capillary-like structures of human vascular endothelial cells cultured on Matrigel. The model combines a Cellular Potts Model, considering cell adhesion, cytoskeletal rearrangement and chemotaxis, and a Partial Differential Equation model describing the release and the diffusion of a chemoattractant. The results were compared with the data from real in vitro experiments to establish the capability of the model to accurately reproduce both the spontaneous self-assembly of unstimulated cells and their self-organization in the presence of the pro-angiogenic factor adrenomedullin. The results showed that the model can accurately reproduce the self-assembly of unstimulated cells, but it failed in reproducing the adrenomedullin-induced self-organization of the cells. The extension of the model to include cell proliferation led to a good match between simulated and experimental patterns in both cases with predicted proliferation rates in agreement with the data of cell proliferation experiments.

Expression of apoptosis-related proteins and of mRNA for dopaminergic receptors in peripheral blood mononuclear cells from patients with Alzheimer disease

In search for biomarkers of neurodegeneration, increasing attention has been focussed on peripheral blood mononuclear cells (PBMC). In particular, PBMC from patients with Alzheimer disease (AD) have been suggested to carry apoptotic changes and alterations of neurotransmitter receptor expression, which may resemble those occurring in central nervous system neurons. We investigated the expression of apoptosis-related proteins Bcl-2, Bax, and caspase-3 and the levels of dopaminergic receptors (DR) D3 and D5 mRNA in PBMC from 17 AD patients and 11 age-matched healthy subjects. Apoptosis-related proteins were assayed by standard Western blotting analysis and DR mRNA by real-time polymerase chain reaction techniques. PBMC from healthy subjects and from AD patients expressed Bcl-2, Bax, and caspase-3 to about the same extent, and the Bcl-2/Bax ratio did not differ in the 2 groups. Levels of mRNA for DRD3 and DRD5 were similar in cells from healthy subjects and from AD patients. In conclusion, we found no evidence that PBMC from AD patients may express apoptosis-related proteins or DR mRNA to any different extent in comparison to cells from healthy subjects. These findings do not necessarily imply that immune cells cannot be exploited as biomarkers in AD (and in other central nervous system disorders). Future studies, however, should take into account the inherent complexity of the immune network.

Immune and nervous systems share molecular and functional similarities: memory storage mechanism

One of the most complex and important features of both the nervous and immune systems is their data storage and retrieval capability. Both systems encounter a common and complex challenge on how to overcome the cumbersome task of data management. Because each neuron makes many synapses with other neurons, they are capable of receiving data from thousands of synaptic connections. The immune system B and T cells have to deal with a similar level of complexity because of their unlimited task of recognizing foreign antigens. As for the complexity of memory storage, it has been proposed that both systems may share a common set of molecular mechanisms. Here, we review the molecular bases of memory storage in neurons and immune cells based on recent studies and findings. The expression of certain molecules and mechanisms shared between the two systems, including cytokine networks, and cell surface receptors, are reviewed. Intracellular signaling similarities and certain mechanisms such as diversity, memory storage, and their related molecular properties are briefly discussed. Moreover, two similar genetic mechanisms used by both systems is discussed, putting forward the idea that DNA recombination may be an underlying mechanism involved in CNS memory storage.

Brain receptor mosaics and their intramembrane receptor-receptor interactions: molecular integration in transmission and novel targets for drug development

The concept of intramembrane receptor-receptor interactions and evidence for their existence was introduced by Agnati and Fuxe in 1980/81 suggesting the existence of heteromerization of receptors. In 1982, they proposed the existence of aggregates of multiple receptors in the plasma membrane and coined the term receptor mosaics (RM). In this way, cell signaling becomes a branched process beginning at the level of receptor recognition at the plasma membrane where receptors can directly modify the ligand recognition and signaling capacity of the receptors within a RM. Receptor-receptor interactions in RM are classified as operating either with classical cooperativity, when consisting of homomers or heteromers of similar receptor subtypes having the same transmitter, or non-classical cooperativity, when consisting of heteromers. It has been shown that information processing within a RM depends not only on its receptor composition, but also on the topology and the order of receptor activation determined by the concentrations of the ligands and the receptor properties. The general function of RM has also been demonstrated to depend on allosteric regulators (e.g., homocysteine) of the receptor subtypes present. RM as integrative nodes for receptor-receptor interactions in conjunction with membrane associated proteins may form horizontal molecular networks in the plasma membrane coordinating the activity of multiple effector systems modulating the excitability and gene expression of the cells. The key role of electrostatic epitope-epitope interactions will be discussed for the formation of the RM. These interactions probably represent a general molecular mechanism for receptor-receptor interactions and, without a doubt, indicate a role for phosphorylation-dephosphorylation events in these interactions. The novel therapeutic aspects given by the RMs will be discussed in the frame of molecular neurology and psychiatry and combined drug therapy appears as the future way to go.

Peripheral cytokines profile in Parkinson's disease

Higher levels of proinflammatory cytokines are found in Parkinson's disease (PD) patient's brains and inflammation is thought to be a major contributor to the neurodegeneration. During the inflammatory process, microglial release of proinflammatory cytokines act on the endothelium of blood-brain barrier (BBB) cells to stimulate upregulation of adhesion molecules. Consequently, this upregulation leads to the recruitment of passing T cells and monocytes, which express the counter receptors, that then go on to release more cytokines [Whitton, P.S., 2007. Inflammation as a causative factor in the aetiology of Parkinson's disease, Br. J. Pharmacol. 50, 963-976; Kortekaas, R., Leenders, K.L., Van Oostrom, J.C., Vaalburg, W., Bart, J., Willemsen, A.T., Hendrikse, N.H., 2005. Blood-brain barrier dysfunction in parkinsonian midbrain in vivo, Ann. Neurol. 57, 176-179]. In addition, a systemic inflammatory response results in the production of cytokines which circulate in the blood and communicate with neurons within the brain. Thus, a central inflammatory reaction interacts with peripheral blood mononuclear cells (PBMCs) modulating immune activity. The present study investigates levels of production and expression of cyto/chemokines by PBMCs in PD patients. Basal and LPS-induced levels of MCP-1, RANTES, MIP-1alpha, IL-8, IFNgamma, IL-1beta and TNFalpha were significantly higher in PD patients than in HC subjects (p<0.001), as determined by RT-PCR and Elisa methods. Cyto/chemokine levels were significantly correlated with UPDRS III and H/Y stage (p<0.001). The Pearson's correlation coefficient (R) was also used to assess the strength of the relationship between NF-kappaBp65 levels and all studied cyto/chemokines and between NF-kappaBp65, UPDRS III and H/Y score in PD patients. The overall results strengthen and extend the knowledge of the peripheral dysregulation in the cytokine network associated with PD.