Peripheral T cells from multiple sclerosis patients trigger synaptotoxic alterations in central neurons.

AIMS: The crucial step in the pathogenic events that lead to the development and the progression of multiple sclerosis (MS) is the infiltration of autoreactive T cells in the brain. Data from experimental autoimmune encephalomyelitis (EAE) mice indicate that, together with microglia, T cells are responsible for the enhancement of the glutamatergic transmission in central neurons, contributing to glutamate-mediated excitotoxicity, a pathological hallmark of both EAE and MS brains. Here, we addressed the synaptic role of T cells taken from MS patients. METHODS: A chimeric model of human T cells and murine brain slices was established to record, by Patch Clamp technique, the glutamatergic transmission in the presence of T cells isolated from the peripheral blood of healthy subjects (HS), active (a) and nonactive (na) relapsing remitting MS patients. Intracellular staining and flow cytometry were used to assess tumour necrosis factor (TNF) expression in T cells. RESULTS: Chimeric experiments indicated that, compared to HS and naMS, T cells from aMS induced an increase in glutamatergic kinetic properties of striatal neurons. Such alteration, reminiscent of the those induced by EAE T cells, was blocked by incubation of the slices with etanercept, a TNF receptor antagonist. Of note, T cells from aMS expressed more TNF than naMS patients and HS subjects. CONCLUSION: These data highlight the synaptotoxic potential retained by MS T cells, suggesting that during the inflammatory phase of the disease infiltrating T cells could influence the neuronal activity contributing to the TNF-mediated mechanisms of glutamate excitotoxicity in central neurons.

Cannabinoid CB2 receptor (CB2R) stimulation delays rubrospinal mitochondrial-dependent degeneration and improves functional recovery after spinal cord hemisection by ERK1/2 inactivation.

Spinal cord injury (SCI) is a devastating condition of CNS that often results in severe functional impairments for which there are no restorative therapies. As in other CNS injuries, in addition to the effects that are related to the primary site of damage, these impairments are caused by degeneration of distal regions that are connected functionally to the primary lesion site. Modulation of the endocannabinoid system (ECS) counteracts this neurodegeneration, and pharmacological modulation of type-2 cannabinoid receptor (CB2R) is a promising therapeutic target for several CNS pathologies, including SCI. This study examined the effects of CB2R modulation on the fate of axotomized rubrospinal neurons (RSNs) and functional recovery in a model of spinal cord dorsal hemisection (SCH) at the cervical level in rats. SCH induced CB2R expression, severe atrophy, and cell death in contralateral RSNs. Furthermore, SCH affected molecular changes in the apoptotic cascade in RSNs - increased cytochrome c release, apoptosome formation, and caspase-3 activity. CB2R stimulation by its selective agonist JWH-015 significantly increased the bcl-2/bax ratio, reduced cytochrome c release, delayed atrophy and degeneration, and improved spontaneous functional recovery through ERK1/2 inactivation. These findings implicate the ECS, particularly CB2R, as part of the endogenous neuroprotective response that is triggered after SCI. Thus, CB2R modulation might represent a promising therapeutic target that lacks psychotropic effects and can be used to exploit ECS-based approaches to counteract neuronal degeneration.

Brain Natriuretic Peptide (BNP) regulates the production of inflammatory mediators in human THP-1 macrophages.

Brain Natriuretic Peptide (BNP), besides retaining vasodilatory, diuretic and natriuretic properties, is a vasoactive hormone that it is also involved in several cardiac diseases as well as severe sepsis and septic shock. All these conditions are characterized by an ongoing inflammatory response consisting in a complex interaction of pleiotropic mediators derived from plasma or cells, including monocytes and macrophages. However, the relationship between this hormone and inflammation remains to be elucidated. Therefore, the aim of the present study was to evaluate a possible BNP immunomodulatory activity on macrophages. Our results demonstrate that BNP regulates the production of major inflammatory molecules, such as reactive oxygen- and nitrogen species (ROS and RNS), leukotriene B(4) (LTB(4)), prostaglandin E(2) (PGE(2)); modulates the cytokines (TNF-alpha, IL-12 and IL-10) profile, and affects cell motility. These results furnish novel and brand-new proofs on BNP ability of modulating the production of inflammatory mediators in macrophages whose role has broad implications in inflammatory states where increased BNP levels have been reported.

Endomorphin-1 inhibits the activation and the development of a hyporesponsive-like phenotype in lipopolysaccharide- stimulated THP-1 monocytes.

Endomorphin-1 (EM-1) is an endogenous opioid peptide selectively binding to micro opioid receptors (MORs). Besides its analgesic effects on the central nervous system (CNS), it has been recently reported that EM-1 can cross the blood-brain barrier (BBB) and diffuse into the blood, behaving as an analgesic/anti-inflammatory molecule on peripheral tissues, thus leading to the hypothesis that it could represent a soluble modulator of immune cell functions. Interestingly, nothing is known about its possible effects on monocytes, the main circulating cell-type involved in those systemic responses, such as fever and septic states, involving the release of high amounts of pyrogenic inflammatory factors. The aim of this work is to evaluate possible EM-1effects on lipopolisaccharide (LPS)-stimulated THP-1 monocytes in terms of the production of inflammatory mediators and the instauration of a hyporesponsive-like phenotype which is a main feature of systemic inflammatory responses, and on the development of peripheral monocytes to DC. Our data demonstrate for the first time that EM-1 is able to inhibit both LPS-stimulated monocyte activation, in terms of arachidonic acid, PGE2, ROI and NO2 production and instauration of a hyporesponsive phenotype without any macroscopic effect on DC development. These data support the hypothesis that EM-1 could be involved in modulating monocyte functions during systemic inflammatory reactions, also providing new evidence for its eventual clinical application in endotoxic states.

Activatory properties of lysophosphatidic acid on human THP-1 cells.

Excessive leukocyte proliferation and proinflammatory mediators release represent common phenomena in several chronic inflammatory diseases. Multiple evidences identify lysophosphatidic acid (LPA), a small lipid endowed with pleiotropic activities, as an important modulator of both proliferation and activation of different cell types involved in several inflammation-associated pathologies. However, its possible role on monocyte proinflammatory activation is not fully understood yet. Aim of the present study was to investigate LPA effects on THP-1 cells in terms of proliferation, reactive oxygen intermediates (ROI) production and release of arachidonic acid-derived inflammatory mediators. Actually, LPA significantly increased both DNA synthesis and ROI production as well as prostaglandin E(2) release and the upregulation of LPA(3) receptor expression. These findings identified LPA as both a growth factor and a triggering mediator of proinflammatory response in THP-1 cells.

Activatory properties of lysophosphatidic acid on human THP-1 cells.

Excessive leukocyte proliferation and proinflammatory mediators release represent common phenomena in several chronic inflammatory diseases. Multiple evidences identify lysophosphatidic acid (LPA), a small lipid endowed with pleiotropic activities, as an important modulator of both proliferation and activation of different cell types involved in several inflammation-associated pathologies. However, its possible role on monocyte proinflammatory activation is not fully understood yet. Aim of the present study was to investigate LPA effects on THP-1 cells in terms of proliferation, reactive oxygen intermediates (ROI) production and release of arachidonic acid-derived inflammatory mediators. Actually, LPA significantly increased both DNA synthesis and ROI production as well as prostaglandin E(2) release and the upregulation of LPA(3) receptor expression. These findings identified LPA as both a growth factor and a triggering mediator of proinflammatory response in THP-1 cells.