Emanuela Galliera

Chemokines and chemokine receptors: an overview.

Chemokines are chemotactic cytokines orchestrating leukocyte recruitment in physiological and pathological conditions. This complex system includes 42 molecules and 19 receptors and is subjected to different levels of regulation, including ligand production, post-translational modifications and degradation, as well as receptor expression and signaling activity. Here we analyze the chemokine system, with particular attention to available information on clinical situations in which chemokines or their receptors might assume diagnostic value.

Differential Recognition and Scavenging of Native and Truncated Macrophage-Derived Chemokine (Macrophage-Derived Chemokine/CC Chemokine Ligand 22) by the D6 Decoy Receptor

The promiscuous D6 receptor binds several inflammatory CC chemokines and has been recently proposed to act as a chemokine-scavenging decoy receptor. The present study was designed to better characterize the spectrum of CC chemokines scavenged by D6, focusing in particular on CCR4 ligands and analyzing the influence of NH2-terminal processing on recognition by this promiscuous receptor. Using D6 transfectants, it was found that D6 efficiently bound and scavenged most inflammatory CC chemokines (CCR1 through CCR5 agonists). Homeostatic CC chemokines (CCR6 and CCR7 agonists) were not recognized by D6. The CCR4 agonists CC chemokine ligand 17 (CCL17) and CCL22 bound to D6 with high affinity. CCL17 and CCL22 have no agonistic activity for D6 (chemotaxis and calcium fluxes), but were rapidly scavenged, resulting in reduced chemotactic activity on CCR4 transfectants. CD26 mediates NH2 terminus processing of CCL22, leading to the production of CCL22 (3–69) and CCL22 (5–69) that do not interact with CCR4. These NH2-terminal truncated forms of CCL22 were not recognized by D6. The results presented in this study show that D6 recognizes and scavenges a wide spectrum of inflammatory CC chemokines, including the CCR4 agonists CCL22 and CCL17. However, this promiscuous receptor is not engaged by CD26-processed, inactive, CCL22 variants. By recognizing intact CCL22, but not its truncated variants, D6 expressed on lymphatic endothelial cells may regulate the traffic of CCR4-expressing cells, such as dendritic cells.

Why menisci show higher healing rate when repaired during ACL reconstruction? Growth factors release can be the explanation

PurposeHealing rate of meniscus repair is higher when the suture is associated with anterior cruciate ligament reconstruction. A possible explanation can be a different pattern of release of growth factors between anterior cruciate ligament reconstruction and isolated meniscus surgery. Hypothesis of this study is that the concentrations of bFGF, TGF-β and platelet-derived growth factor (PDGF) in joint fluid, immediately after single-bundle anterior cruciate ligament reconstruction and arthroscopic partial meniscectomy, can be different.MethodsTwenty consecutive patients underwent partial medial meniscectomy and twenty consecutive patients underwent single-bundle anterior cruciate ligament reconstruction with hamstring grafts were enrolled in the study. Thirty minutes after the end of the surgical procedure, a sample of joint fluid, as well of venous blood, was collected from all the patients. Concentrations of growth factors were determined by enzyme-linked immunosorbent assay.ResultsThe peripheral blood concentration of TGF-β, bFGF and PDGF was comparable between partial meniscectomy and anterior cruciate ligament reconstruction groups. No differences between the two surgical techniques were also found in term of TGF-β and bFGF joint fluid concentration, whereas joint PDGF concentration of anterior cruciate ligament reconstruction patients was significantly higher than the one found in partial meniscectomy patients.ConclusionsA significant growth factors release was detected in the knee joint during arthroscopic surgery. PDGF concentration was significantly higher in anterior cruciate ligament reconstructed knee than in the meniscectomy group. PDGF can play an important role enhancing the healing response of meniscus suture and can be one of the biological reasons of the higher meniscal healing rate in anterior cruciate ligament reconstructed knee.

Receptor binding mode and pharmacological characterization of a potent and selective dual CXCR1/CXCR2 non-competitive allosteric inhibitor

BACKGROUND AND PURPOSE DF 2156A is a new dual inhibitor of IL‐8 receptors CXCR1 and CXCR2 with an optimal pharmacokinetic profile. We characterized its binding mode, molecular mechanism of action and selectivity, and evaluated its therapeutic potential.

Tuning of Innate Immunity and Polarized Responses by Decoy Receptors

After the identification of the interleukin (IL)-1 type II receptor as the prototype, decoy receptors have been identified for a number of members of the IL-1/IL-18, TNF, IL-10 and IL-13 receptor families. Moreover, the silent receptor D6 is a promiscuous decoy and scavenger receptor of inflammatory chemokines. The IL-1 decoy receptor is regulated by pro- and anti-inflammatory signals and its levels may serve as a readout of the activation of anti-inflammatory pathways, for instance by glucocorticoid hormones. Decoy receptors represent a strategy to tune inflammatory and polarized adaptive responses.

Age-related changes in plasma levels of BDNF in Down syndrome patients

BackgroundThe prevalence of coronary artery diseases is low among Down Syndrome (DS) patients and they rarely die of atherosclerotic complications. Histopathological investigations showed no increase in atherosclerosis, or even a total lack of atherosclerotic changes, in DSAimThe aim of our study is to investigate the relationship between age and brain-derived neurotrophic factor (BDNF) levels in Down Syndrome (DS).Subjects and methodsThree groups of DS patients were studied: the first consisted of 23 children (age 2-14 years); the second of 14 adults (age 20-50 years), the third group of 13 elderly persons (>60 years) and a controls group of 20 healthy patients (age 15-60 years).The analytes of interest were quantified using a biochip array analyzer (Evidence®, Randox Ltd., Crumlin, UK).ResultsPlasma BDNF was higher in DS patients than in controls and there was a significant age-related increase. Serum levels of IL-6 and MCP-1 were also higher in DS children and adults, but not in older patients, than in healthy control. High levels of circulating BDNF may protect DS patients from the clinical complications of atherosclerosis. However, the striking drop in peripheral BDNF levels with age might predispose these patients to clinical manifestations of dementia in later life.

Targeting the minor pocket of C5aR for the rational design of an oral allosteric inhibitor for inflammatory and neuropathic pain relief

Significance Persistent pain in inflammatory and neuropathic conditions is often refractory to conventional analgesic therapy, with most patients suffering with unrelieved pain and serious treatment-related side effects. There is still a tremendous need to identify novel therapeutics for pain control with innovative biological mechanisms and minimal side effects. In this paper we challenge the hypothesis that a conserved structural motif across the G protein-coupled receptor family plays a regulatory role in the negative modulation of receptor activation and use a multidisciplinary approach to the rational drug design and characterization of a novel potent allosteric inhibitor of the C5a anaphylatoxin receptor (C5aR), thus providing a new promising avenue for the improvement of pharmacotherapy of chronic pain. Chronic pain resulting from inflammatory and neuropathic disorders causes considerable economic and social burden. Pharmacological therapies currently available for certain types of pain are only partially effective and may cause severe adverse side effects. The C5a anaphylatoxin acting on its cognate G protein-coupled receptor (GPCR), C5aR, is a potent pronociceptive mediator in several models of inflammatory and neuropathic pain. Although there has long been interest in the identification of C5aR inhibitors, their development has been complicated, as for many peptidomimetic drugs, mostly by poor drug-like properties. Herein, we report the de novo design of a potent and selective C5aR noncompetitive allosteric inhibitor, DF2593A, guided by the hypothesis that an allosteric site, the “minor pocket,” previously characterized in CXC chemokine receptors-1 and -2, is functionally conserved in the GPCR class. In vitro, DF2593A potently inhibited C5a-induced migration of human and rodent neutrophils. In vivo, oral administration of DF2593A effectively reduced mechanical hyperalgesia in several models of acute and chronic inflammatory and neuropathic pain, without any apparent side effects. Mechanical hyperalgesia after spared nerve injury was also reduced in C5aR−/− mice compared with WT mice. Furthermore, treatment of C5aR−/− mice with DF2593A did not produce any further antinociceptive effect compared with C5aR−/− mice treated with vehicle. The successful medicinal chemistry strategy confirms that a conserved minor pocket is amenable for the rational design of selective inhibitors and the pharmacological results support that the allosteric blockade of the C5aR represents a highly promising therapeutic approach to control chronic inflammatory and neuropathic pain.

Matrix metalloproteinases as biomarkers of disease: updates and new insights.

Abstract Matrix metalloproteinases (MMPs) play a pivotal role in remodeling the extracellular matrix (ECM) and are therefore of interest for new diagnostic tools for the clinical management of diseases involving ECM disruption. This setting ranges from the classical areas of MMP studies, such as vascular disease, cancer progression or bone disorders, to new emerging fields of application, such as neurodegenerative disease or sepsis. Increasing the knowledge about the role of MMPs in the pathogenesis of diseases where a clear diagnostic panel is still lacking could provide new insight and improve the identification and the clinical treatment of these human diseases. This review focuses on the latest descriptions of the clinical use of MMP as biomarkers in the diagnosis, prognosis and monitoring of different diseases, such as diabetes, cardiovascular diseases, cancer and metastasis, neurodegenerative disorders and sepsis.

Leptin, ciliary neurotrophic factor, leukemia inhibitory factor and interleukin-6: Class-I cytokines involved in the neuroendocrine regulation of the reproductive function

Class-I cytokines represent a large group of molecules involved in different physiological processes including host defence, immune regulation, food intake, energy metabolism and, relevant for this review, reproduction. In this latter respect, here, we focus the attention on four of these molecules, specifically leptin, ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF) and interleukin-6 (IL-6). These cytokines present similar three-dimensional fold structure, interact with related class-I receptors, which are expressed in the same regions (i.e., hypothalamus), and activate similar intracellular pathways. Leptin and CNTF share functional similarities, by acting at hypothalamic and pituitary levels, and their receptors are colocalized in the arcuate and paraventricular nuclei of the hypothalamus. For both these molecules, no effect on GnRH migration has been described. LIF has also been shown to affect gonadotropin secretion and here we present the novel observation that it is also able to stimulate GnRH secretion in vitro. Moreover, in the mouse, LIF is prenatally expressed in nasal regions where GnRH neurons originate and start their migration, and in vitro it stimulates intrinsic cell motility and directional migration. The role of the prototypical cytokine, IL-6, on the GnRH-LH axis is not fully clear and additional information seem necessary to better clarify this aspect. In conclusion, the data here discussed suggest that this family of cytokines appears to participate to the complex control of the reproductive function by affecting the development and function of the hypothalamus-pituitary system at different ontogenic times and anatomical sites.

Reduced plasma levels of P-selectin and L-selectin in a pilot study from Alzheimer disease: relationship with neuro-degeneration

Neurodegenerative processes associated with Alzheimer’s disease (AD) are accompanied by reactive astrogliosis and microglia activation and a role for chronic inflammation in the brain degeneration of these patients has been suggested. Moreover impaired immune functions in AD brains might also influence the disease’s progression. Therefore, it is of interest to further characterized inflammatory molecules in the peripheral blood of patients with AD and its relationship with cognitive decline. A complex picture emerged in this pilot study and IL-8, IFN-gamma, MCP-1 and VEGF levels were increased in AD. Levels of P-selectin and L-selectin were decreased in AD and lowest in AD patients with highest cognitive decline. Our findings suggest that these molecules may induce alterations of endothelial regulation and influence neurodegenerative processes of AD.