The alternatively spliced fibronectin CS1 isoform regulates IL-17A levels and mechanical allodynia after peripheral nerve injury

Abstract

BackgroundMechanical pain hypersensitivity associated with physical trauma to peripheral nerve depends on T-helper (Th) cells expressing the algesic cytokine, interleukin (IL)-17A. Fibronectin (FN) isoform alternatively spliced within the IIICS region encoding the 25-residue-long connecting segment 1 (CS1) regulates T cell recruitment to the sites of inflammation. Herein, we analyzed the role of CS1-containing FN (FN-CS1) in IL-17A expression and pain after peripheral nerve damage.MethodsMass spectrometry, immunoblotting, and FN-CS1-specific immunofluorescence analyses were employed to examine FN expression after chronic constriction injury (CCI) in rat sciatic nerves. The acute intra-sciatic nerve injection of the synthetic CS1 peptide (a competitive inhibitor of the FN-CS1/α4 integrin binding) was used to elucidate the functional significance of FN-CS1 in mechanical and thermal pain hypersensitivity and IL-17A expression (by quantitative Taqman RT-PCR) after CCI. The CS1 peptide effects were analyzed in cultured primary Schwann cells, the major source of FN-CS1 in CCI nerves.ResultsFollowing CCI, FN expression in sciatic nerve increased with the dominant FN-CS1 deposition in endothelial cells, Schwann cells, and macrophages. Acute CS1 therapy attenuated mechanical allodynia (pain from innocuous stimulation) but not thermal hyperalgesia and reduced the levels of IL-17A expression in the injured nerve. CS1 peptide inhibited the LPS- or starvation-stimulated activation of the stress ERK/MAPK pathway in cultured Schwann cells.ConclusionsAfter physical trauma to the peripheral nerve, FN-CS1 contributes to mechanical pain hypersensitivity by increasing the number of IL-17A-expressing (presumably, Th17) cells. CS1 peptide therapy can be developed for pharmacological control of neuropathic pain.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-015-0377-6) contains supplementary material, which is available to authorized users.

Spinal activity of interleukin 6 mediates myelin basic protein-induced allodynia

“…Generally, Th1 and Th17 cells expressing algesic cytokines sustain pain that follows PNS trauma, whereas Th2 and Treg cells expressing analgesic cytokines inhibit pain processing [4–6, 8, 9, 13, 54–58]. Evidence exists that persistent pain states involving nerve but not surrounding tissue damage activate adaptive immunity [59].…”

The extra domain A of fibronectin facilitates osteoclastogenesis in radicular cysts through vascular endothelial growth factor

“…Fibronectin (FN) is the main component of the ECM, and in most normal adult tissues, isoforms containing domains EDA (EDA + FN), EDB (EDB + FN) and IIICS (CS1‐FN) are absent (Liu et al , Lv et al ). However, myofibroblasts generate these isoforms via alternative splicing of the FN gene, especially during inflammation, wound healing or tumour formation (Kalluri & Zeisberg ), suggesting their involvement in bone destruction (Elmusrati et al ).…”

“…For instance, EDA + FN is distributed within the stroma of ameloblastoma (Heikinheimo et al ). Radicular cysts are initiated by chronic inflammation, and inflammatory factors within the fibrous capsules tend to stimulate generation of EDB + FN and CS1‐FN (Boyle et al , Khan et al , Liu et al ). Considering the participation of FN isoforms in tumour aggressiveness (Kamarajan et al , Wang et al 2015a, Wang et al 2015b), bone destruction resulting from odontogenic cysts may be affected by FN isoforms as well.…”

“…The effects of FN isoforms on osteoclastogenesis may contribute to bone destruction due to the inflammatory microenvironment of radicular cysts (Khan et al , Khan et al , Liu et al ). Since the three main splice variants, EDA + FN, EDB + FN and CS1‐FN, are ligands of integrin receptors and Toll‐like receptor 4 (TLR4), interactions between FN isoforms and receptors in pre‐osteoclasts may directly affect osteoclastogenesis (Doddapattar et al , Jiang et al ), whilst their interaction in other cells could alter the expression of osteoclastogenic genes, such as vascular endothelial growth factor (VEGF) or IL‐17 (Liu et al , Lv et al ), by which osteoclastogenesis can be indirectly influenced. Therefore, this study explored the effects of FN isoforms on bone destruction in radicular cysts, as well as the underlying mechanism through antibody blocking and gene editing using the type II bacterial clustered, regularly interspaced, palindromic repeats (CRISPR)‐associated (Cas) system (Kohan et al , Wang et al 2015a, Wang et al 2015b).…”

Fibronectin connecting segment-1 peptide inhibits pathogenic leukocyte trafficking and inflammatory demyelination in experimental models of chronic inflammatory demyelinating polyradiculoneuropathy

“…Vascular cell adhesion molecule-1 (VCAM-1) is also a counterligand for α 4 integrin implicated in lymphocyte migration during infection and inflammation, as well as lymphocyte bone marrow retention and homing into lymph nodes via high endothelial venules during normal immune processes (Boscacci et al, 2010; Faveeuw et al, 2000; Koni et al, 2001; Papayannopoulou and Craddock, 1997; Xu et al, 2003). Competitive antagonism of FNCS1-α 4 integrin binding with small molecular antagonists that target the LDV peptide sequence could result in a specific disease modifying therapy for CIDP without interfering with α 4 integrin-VCAM-1 binding implicated in normal immunity (Haworth et al, 1999; Jackson, 2002; Liu et al, 2015; Man et al, 2009; Ubogu et al, 2006). …”