Macrophage-derived netrin-1 contributes to endometriosis- associated pain

Abstract

Background: Endometriosis-associated pain can be considered a type of neuropathic pain. Netrin-1 is an axon guidance cue that regulates axonal attraction or rejection in neural injury and regeneration. However, whether netrin-1 plays a role in endometriosis-associated pain remains unclear. This study aimed to determine the role of netrin-1 in endometriosis-related pain. Methods: Peripheral blood, peritoneal fluid, and endometrial tissues were sampled from women with (n=37) and without endometriosis (n=23). Lipopolysaccharide (LPS) and interferon gamma (IFN-γ) were used to stimulate human monocytic cell lines (THP-1) and rat alveolar macrophage-derived cell lines (NR8383) to induce M1 phenotype macrophages. Serum netrin-1 concentrations, endometrial expression levels of netrin-1, and its receptors including deleted in colorectal cancer (DCC), A2B adenosine receptor (A2BAR), uncoordinated B receptor (UNC5B), uncoordinated C receptor (UNC5C) and Down's syndrome cell adhesion molecule (DSCAM) were assessed. The polarization phenotypes of the peritoneal macrophages were identified by detecting the marker expression of M1/M2 macrophages via flow cytometry. The expression levels of M1 markers and netrin-1 in THP-1/NR8383 cells were determined.Results: The expression levels of netrin-1 in serum and endometriotic lesions were significantly higher in women with endometriosis, and were positively correlated with the severity of endometriosis-associated pain.Netrin-1 was co-expressed with CD68 (a macrophage marker) in endometriotic lesions and was synthesized and secreted by THP-1 and NR8383 cells in the process of M1 polarization. In women with endometriosis, peritoneal macrophages were polarized towards the M1 phenotype. In addition, increased expression of DCC and A2BAR, and decreased expression of UNC5B, UNC5C and DSCAM were found in endometriotic lesions.Conclusions: These results suggest that netrin-1 production by macrophages in endometriotic lesions may play an important role in endometriosis-associated pain.

Spinal TRPA1 Contributes to the Mechanical Hypersensitivity Effect Induced by Netrin-1

“…The hypersensitivity effect is submodality-selective as shown by the finding that netrin-1 did not influence heat nociception. The hypersensitivity effect of netrin-1 in the present study is in line with earlier results reporting that netrin-1 is associated with pain in various experimental and pathophysiological conditions [ 5 , 6 , 7 , 8 , 9 , 13 ] and that the DCC receptor, a key mediator of attractive signaling by netrin-1 [ 2 ], may be mediating pronociceptive effects of netrin-1 [ 5 , 6 , 7 , 11 , 13 ]. The present study extends earlier findings by showing that a single intrathecal dose of netrin-1 does not only induce acute hypersensitivity in rodents [ 7 ], but it may induce a prolonged neuropathy-like pain hypersensitivity condition lasting at least up to three weeks.…”

“…Studies on samples of osteoarthritis patients suggest that osteoclasts secrete excessive amounts of netrin-1 and induce sensory innervation and pain in the arthritic joint [ 10 ]. In addition, human studies have reported that in patients with endometriosis, netrin-1 and DCC levels are increased in endometrial tissues [ 11 ], and patients with small fiber neuropathy have increased netrin-1 gene expression in keratinocytes [ 12 ]. In genome-wide analysis, the DCC netrin-1 receptor gene was identified as the top gene associated with multisite pain [ 13 ].…”

“…Moreover, netrin receptors DCC, TRPC4/C5, and TRPA1 mRNA are colocalized in a number of human and rodent sensory neuron subtypes [ 25 , 26 ]. Further, it is possible that macrophages play a role in DCC-induced pain phenotype as macrophage-derived netrin was recently shown to contribute to endometriosis-associated pain [ 11 ]. To test our working hypothesis, we determined whether pain behavior induced by spinal administration of netrin-1 could be reversed with antagonists of TRPA1 or TRPC4/C5.…”

Niclosamide targets macrophages to rescue the disrupted peritoneal homeostasis in endometriosis

“…Peritoneal macrophages infiltrate endometriotic lesions and promote their growth and vascularization by releasing proinflammatory cytokines and growth factors (Bacci et al, 2009; Cheong et al, 2002; Sekiguchi et al, 2019; Shi et al, 2021). In addition, IGF1 and netrin-1, along with cytokines secreted by macrophages, also promote neurogenesis and innervation at lesion sites, which enhances the pain sensation in patients (Ding et al, 2021; Forster et al, 2019; Greaves et al, 2015; Scholl et al, 2009). The proinflammatory cytokines released by macrophages disrupted in endometriosis also affect multiple important activities of reproduction, such as hormonal balances and decidualization, leading to infertility (De Ziegler et al, 2010; Rasheed and Hamid, 2020).…”

A nomogram for bladder pain syndrome/interstitial cystitis based on netrin-1

“…Recent studies have revealed that netrin-1, a novel neuro-immune inflammatory factor, regulates the migration of inflammatory cells such as macrophages and the secretion of inflammatory factors [ 8 ]. In addition, netrin-1 has been associated with inflammatory pain in osteoarthritis and chronic pelvic pain associated with endometriosis [ 9 , 10 ]. BPS/IC, a sterile inflammatory disease, has chronic pelvic pain as one of its main symptoms, and it is unclear whether netrin-1 is involved in the pathogenesis of BPS/IC.…”