The Novel C5aR Antagonist DF3016A Protects Neurons Against Ischemic Neuroinflammatory Injury

Abstract

The central nervous system (CNS) constitutively expresses complement (C) membrane receptors and complement proteins, including the component C5a. This is a crucial terminal effector of the C cascade, mostly involved in pain and neuroinflammatory conditions. Aberrant activation of C5a protein and its receptor C5aR has been reported to play a critical role in neurodegenerative diseases, with important clinical consequences. Here we have investigated the effects of DF3016A, a novel selective C5aR antagonist, able to penetrate the blood-brain barrier (BBB), on cortical neurons exposed to oxygen-glucose deprivation-reoxygenation (OGD/R), a neuroinflammation-related process. We demonstrated that a mild ischemic insult induces an early upregulation of C5aR associated with the over-production of pro-inflammatory cytokines and the over-expression of the transcriptional regulatory factor miR-181. Furthermore, we report the first experimental evidence of the effect of DF3016A, modulating complement component C5a, on neurons in a model of injury. Interestingly, DF3016A protects neuronal viability by restoring intracellular calcium levels, thus opposing the increase in pro-inflammatory cytokine levels and miR-181 expression. Based on our results, we suggest that DF3016A is a novel C5aR antagonist promoting protective effects against OGD/R-induced damage that could be a new therapeutic approach to controlling CNS neuroinflammatory conditions.

Epigenetic scores for the circulating proteome as tools for disease prediction

“…C5 is cleaved into C5a and C5b as part of the immune response 41 and elevated levels of these peptides have been associated with severe inflammatory, autoimmune and neurodegenerative states 424344 . A range of C5-targetting therapeutic approaches are currently in development [44][45][46][47][48][49] . EpiScores for acute inflammatory markers have been shown to offer stable longitudinal measurements of the inflammatory state of an individual, which is likely due to DNA methylation reflecting a more consistent profile of stress in the body than protein measurements 23,25 .…”

Towards an Effective and Safe Treatment of Inflammatory Pain: A Delphi-Guided Expert Consensus

“…Other aspects of the inflammatory cascade should become a target for new drugs and potentially block the inflammatory process and its consequences on the tissues. In this respect, it seems that the antagonism of the C5aR and/or the mast cells would be promising, especially for neuroinflammation [7, 8]. The future should reserve interesting surprises for physicians and guarantee a safer approach to patients with inflammatory pain.…”

“…This adaptive function is one that can exacerbate painful symptoms. The inflammatory cascade is complex but the discontinuation of the inflammatory process represents a potential target to reduce painful conditions [7, 8]. Inflammatory pain reflects sensitization mechanisms, whose consequences are hyperalgesia and/or allodynia.…”

Emerging Role of C5 Complement Pathway in Peripheral Neuropathies: Current Treatments and Future Perspectives

“…Due to the unavailability of the crystal structure of C5aR protein, the design of this novel class of allosteric small-molecular-weight C5aR inhibitors was conducted using a homology modelling approach by exploiting combined information on structural and functional features of allosteric sites in homologous chemokine receptors [40]. Starting from the results on DF2593A, additional medicinal chemistry, in vitro, and in vivo pharmacological studies led to the identification and characterization of novel chemical classes of C5aR allosteric inhibitors, thus allowing the selection of a second generation and new lead compound, DF3966A, with optimized pharmacokinetic and safety profiles but with the same activity and selectivity previously observed [128].…”