Bone Marrow-Derived IL-1Ra Increases TNF Levels Poststroke

Tumor necrosis factor (TNF) and interleukin-1 receptor antagonist (IL-1Ra) are key players in stroke, a disease in which cell-based therapies have shown great potential. Having shown an infarct-reducing effect of bone marrow (BM) cells, especially cells with high IL-1Ra expression, we here investigated the effect of BM cells on TNF and other stroke-related mediators in mice after transient middle cerebral artery occlusion (tMCAo) and in vitro using adult microglial cultures. We analyzed stroke-related genes and inflammatory mediators using qPCR stroke Tier panels, electrochemiluminescence, or enzyme-linked immunosorbent assays. We found a significant correlation and cellular colocalization between microglial-derived TNF and IL-1Ra, though IL-1Ra production was TNF independent. BM treatment significantly increased TNF, interleukin (IL)-10, and IL-4 levels, while C-X-C motif ligand 1 (CXCL1), IL-12p70, and Toll-like receptor 2 (TLR2) decreased, suggesting that BM treatment favors an anti-inflammatory environment. Hierarchical clustering identified Tnf and IL-1rn within the same gene cluster, and subsequent STRING analysis identified TLR2 as a shared receptor. Although IL-1Ra producing BM cells specifically modulated TNF levels, this was TLR2 independent. These results demonstrate BM cells as modulators of poststroke inflammation with beneficial effects on poststroke outcomes and place TNF and IL-1Ra as key players of the defense response after tMCAo

Selective inhibition of soluble tumor necrosis factor alters the neuroinflammatory response following moderate spinal cord injury in mice

Clinical and animal model studies have implicated inflammation and glial and peripheral im-mune cell responses in the pathophysiology of spinal cord injury (SCI). A key player in the in-flammatory response after SCI is the pleiotropic cytokine tumor necrosis factor (TNF), which ex-ists both in both transmembrane (tmTNF) and a soluble (solTNF) form. In the present study, we extend our previous findings of a therapeutic effect of topically blocking solTNF signaling after SCI for three consecutive days on lesion size and functional outcome to study the effect on spatio-temporal changes in the inflammatory response after SCI in mice treated with the selective solTNF inhibitor XPro1595 and compared to saline-treated mice. We found that despite compa-rable TNF and TNF receptor levels between XPro1595- and saline-treated mice, XPro1595 transi-ently decreased pro-inflammatory interleukin (IL)-1 and IL-6 levels and increased pro-regenerative IL-10 levels in the acute phase after SCI. This was complemented by a decrease in the number of infiltrated leukocytes (macrophages and neutrophils) in the lesioned area of the spinal cord and an increase in the number of microglia in the peri-lesion area 14 days after SCI, fol-lowed by a decrease in microglial activation in the peri-lesion area 21 days after SCI. This trans-lated into increased myelin preservation and improved functional outcomes in XPro1595-treated mice 35 days after SCI. Collectively, our data suggests that selective targeting of solTNF time-dependently modulates the neuroinflammatory response by favoring a pro-regenerative envi-ronment in the lesioned spinal cord, leading to improved functional outcomes. Clinical and animal model studies have implicated inflammation and glial and peripheral immune cell responses in the pathophysiology of spinal cord injury (SCI). A key player in the inflammatory response after SCI is the pleiotropic cytokine tumor necrosis factor (TNF), which exists both in both a transmembrane (tmTNF) and a soluble (solTNF) form. In the present study, we extend our previous findings of a therapeutic effect of topically blocking solTNF signaling after SCI for three consecutive days on lesion size and functional outcome to study the effect on spatio-temporal changes in the inflammatory response after SCI in mice treated with the selective solTNF inhibitor XPro1595 and compared to saline-treated mice. We found that despite comparable TNF and TNF receptor levels between XPro1595- and saline-treated mice, XPro1595 transiently decreased pro-inflammatory interleukin (IL)-1β and IL-6 levels and increased pro-regenerative IL-10 levels in the acute phase after SCI. This was complemented by a decrease in the number of infiltrated leukocytes (macrophages and neutrophils) in the lesioned area of the spinal cord and an increase in the number of microglia in the peri-lesion area 14 days after SCI, followed by a decrease in microglial activation in the peri-lesion area 21 days after SCI. This translated into increased myelin preservation and improved functional outcomes in XPro1595-treated mice 35 days after SCI. Collectively, our data suggest that selective targeting of solTNF time-dependently modulates the neuroinflammatory response by favoring a pro-regenerative environment in the lesioned spinal cord, leading to improved functional outcomes

Selective Inhibition of Soluble Tumor Necrosis Factor Alters the Neuroinflammatory Response following Moderate Spinal Cord Injury in Mice

Clinical and animal model studies have implicated inflammation and glial and peripheral immune cell responses in the pathophysiology of spinal cord injury (SCI). A key player in the inflammatory response after SCI is the pleiotropic cytokine tumor necrosis factor (TNF), which exists both in both a transmembrane (tmTNF) and a soluble (solTNF) form. In the present study, we extend our previous findings of a therapeutic effect of topically blocking solTNF signaling after SCI for three consecutive days on lesion size and functional outcome to study the effect on spatio-temporal changes in the inflammatory response after SCI in mice treated with the selective solTNF inhibitor XPro1595 and compared to saline-treated mice. We found that despite comparable TNF and TNF receptor levels between XPro1595- and saline-treated mice, XPro1595 transiently decreased pro-inflammatory interleukin (IL)-1β and IL-6 levels and increased pro-regenerative IL-10 levels in the acute phase after SCI. This was complemented by a decrease in the number of infiltrated leukocytes (macrophages and neutrophils) in the lesioned area of the spinal cord and an increase in the number of microglia in the peri-lesion area 14 days after SCI, followed by a decrease in microglial activation in the peri-lesion area 21 days after SCI. This translated into increased myelin preservation and improved functional outcomes in XPro1595-treated mice 35 days after SCI. Collectively, our data suggest that selective targeting of solTNF time-dependently modulates the neuroinflammatory response by favoring a pro-regenerative environment in the lesioned spinal cord, leading to improved functional outcomes

The Inflammatory Response after Moderate Contusion Spinal Cord Injury: A Time Study

Spinal cord injury (SCI) initiates detrimental cellular and molecular events that lead to acute and delayed neuroinflammation. Understanding the role of the inflammatory response in SCI requires insight into the temporal and cellular synthesis of inflammatory mediators. We subjected C57BL/6J mice to SCI and investigated inflammatory reactions. We examined activation, recruitment, and polarization of microglia and infiltrating immune cells, focusing specifically on tumor necrosis factor (TNF) and its receptors TNFR1 and TNFR2. In the acute phase, TNF expression increased in glial cells and neuron-like cells, followed by infiltrating immune cells. TNFR1 and TNFR2 levels increased in the delayed phase and were found preferentially on neurons and glial cells, respectively. The acute phase was dominated by the infiltration of granulocytes and macrophages. Microglial/macrophage expression of Arg1 increased from 1–7 days after SCI, followed by an increase in Itgam, Cx3cr1, and P2ry12, which remained elevated throughout the study. By 21 and 28 days after SCI, the lesion core was populated by galectin-3+, CD68+, and CD11b+ microglia/macrophages, surrounded by a glial scar consisting of GFAP+ astrocytes. Findings were verified in postmortem tissue from individuals with SCI. Our findings support the consensus that future neuroprotective immunotherapies should aim to selectively neutralize detrimental immune signaling while sustaining pro-regenerative processes

Microglial TNFR2 signaling regulates the inflammatory response after CNS injury in a sex-specific fashion

Microglia, the resident immune cells of the central nervous system (CNS), play a major role indamage progression and tissue remodeling after acute CNS injury, including ischemic stroke(IS) and spinal cord injury (SCI). Understanding the molecular mechanisms regulatingmicroglial responses to injury may thus reveal novel therapeutic targets to promote CNS repair.Here, we investigated the role of microglial tumor necrosis factor receptor 2 (TNFR2), atransmembrane receptor previously associated with pro-survival and neuroprotectiveresponses, in shaping the neuroinflammatory environment after CNS injury. By inducingexperimental IS and SCI in Cx3cr1CreER:Tnfrsf1bfl/fl mice, selectively lacking TNFR2 inmicroglia, and corresponding Tnfrsf1bfl/fl littermate controls, we found that ablation ofmicroglial TNFR2 significantly reduces lesion size and pro-inflammatory cytokine levels, andfavors infiltration of leukocytes after injury. Interestingly, these effects were paralleled byopposite sex-specific modifications of microglial reactivity, which was found to be limited infemale TNFR2-ablated mice compared to controls, whereas it was enhanced in males. Inaddition, we show that TNFR2 protein levels in the cerebrospinal fluid (CSF) of humansubjects affected by IS and SCI, as well as healthy donors, significantly correlate with diseasestage and severity, representing a valuable tool to monitor the inflammatory response afteracute CNS injury. Hence, these results advance our understanding of the mechanismsregulating microglia reactivity after acute CNS injury, aiding the development of sex- andmicroglia-specific, personalized neuroregenerative strategies