Anti-allodynic effect of intrathecal antibodies against macrophage-inducible C-type lectin in spinal nerve ligation model in rat

Abstract

Introduction: Macrophage-inducible C-type lectin (Mincle) has emerged as a potential contributor to neuropathic pain induction and neuroinflammatory responses within the spinal cord. Moreover, evidence suggests a close association between toll-like receptor (TLR) and Mincle expression in myeloid cells. This study evaluated the effectiveness of Mincle antibodies in neuropathic pain and identified the epitope of these antibodies. In addition, the mode of interaction between Mincle and TLR inhibition was explored using isobolographic analysis. Methods: Three different Mincle antibodies and a specific TLR4 inhibitor (TAK-242) were intrathecally administered, and mechanical allodynia was evaluated using the von Frey test in a rat model of spinal nerve ligation (SNL). Isobolographic analysis was conducted on the effect of combination of TAK-242 and Mincle Ab. Microarray analysis examined the specific region of Mincle targeted by the antibodies. Results: All Mincle antibodies and TAK-242 significantly alleviated mechanical allodynia in a dose-dependent manner. However, the maximal possible effects (MPE) produced by the antibodies ranged widely from 37.1 % to 91.8 %, comparable to that of TAK-242 (88.7 %). The combination of TAK-242 and the antibody with the highest MPE resulted in an additive interaction for their anti-allodynic effects. Epitope mapping revealed that each antibody targeted the extracellular domain, with epitope lengths ranging from 5 to 15 amino acids. Conclusions: The current study demonstrates the anti-allodynic effect of Mincle antibodies and additive interaction with TLR4 inhibition in spinal nerve ligation model, suggesting the potential of blocking of Mincle signaling with its antibodies as a novel treatment strategy for neuropathic pain.