CXCL12 and CXCR4 proteins and mRNAs were monitored in the dorsal root ganglia (DRGs) of lumbar (L4-L5) and cervical (C7-C8) spinal segments of naïve rats, rats subjected to sham operation, and those undergoing unilateral complete sciatic nerve transection (CSNT) on post-operation day 7 (POD7). Immunohistochemical, Western blot, and RT-PCR analyses revealed bilaterally increased levels of CXCR4 protein and mRNA in both lumbar and cervical DRG neurons after CSNT. Similarly, CXCL12 protein levels increased, and CXCL12 mRNA was upregulated primarily in lumbar DRGs ipsilateral to the nerve lesion. Intrathecal application of the CXCR4 inhibitor AMD3100 following CSNT reduced CXCL12 and CXCR4 protein levels in cervical DRG neurons, as well as the length of afferent axons regenerated distal to the ulnar nerve crush. Furthermore, treatment with the CXCR4 inhibitor decreased levels of activated Signal Transducer and Activator of Transcription 3 (STAT3), a critical transforming factor in the neuronal regeneration program. Administration of IL-6 increased CXCR4 levels, whereas the JAK2-dependent STAT3 phosphorylation inhibitor (AG490) conversely decreased CXCR4 levels. This indicates a link between the CXCL12/CXCR4 signaling axis and IL-6-induced activation of STAT3 in the sciatic nerve injury-induced pro-regenerative state of cervical DRG neurons. The role of CXCR4 signaling in the axon-promoting state of DRG neurons was confirmed through in vitro cultivation of primary sensory neurons in a medium supplemented with CXCL12, with or without AMD3100. The potential involvement of conditioned cervical DRG neurons in the induction of neuropathic pain is discussed.

• Klíčová slova
• AMD3100, IL-6, STAT3, axon regeneration, pre-conditioning, sciatic nerve, transection,
• MeSH
• benzylaminy MeSH
• chemokin CXCL12 metabolismus   genetika   MeSH
• cyklamy MeSH
• interleukin-6 metabolismus   farmakologie   MeSH
• krysa rodu Rattus MeSH
• nemoci sedacího nervu * metabolismus   MeSH
• nervové receptory * metabolismus   MeSH
• nervus ischiadicus * zranění   metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• receptory CXCR4 * metabolismus   genetika   MeSH
• regenerace nervu * MeSH
• signální transdukce * MeSH
• spinální ganglia metabolismus   MeSH
• transkripční faktor STAT3 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• benzylaminy MeSH
• chemokin CXCL12 MeSH
• CXCL12 protein, rat MeSH Prohlížeč
• Cxcr4 protein, rat MeSH Prohlížeč
• cyklamy MeSH
• interleukin-6 MeSH
• plerixafor MeSH Prohlížeč
• receptory CXCR4 * MeSH
• Stat3 protein, rat MeSH Prohlížeč
• transkripční faktor STAT3 MeSH

Recent evidence indicates that targeting IL-6 provides broad therapeutic approaches to several diseases. In patients with cancer, autoimmune diseases, severe respiratory infections [e.g. coronavirus disease 2019 (COVID-19)] and wound healing, IL-6 plays a critical role in modulating the systemic and local microenvironment. Elevated serum levels of IL-6 interfere with the systemic immune response and are associated with disease progression and prognosis. As already noted, monoclonal antibodies blocking either IL-6 or binding of IL-6 to receptors have been used/tested successfully in the treatment of rheumatoid arthritis, many cancer types, and COVID-19. Therefore, in the present review, we compare the impact of IL-6 and anti-IL-6 therapy to demonstrate common (pathological) features of the studied diseases such as formation of granulation tissue with the presence of myofibroblasts and deposition of new extracellular matrix. We also discuss abnormal activation of other wound-healing-related pathways that have been implicated in autoimmune disorders, cancer or COVID-19.

• Klíčová slova
• Cancer stroma, Granulation tissue, IL-6, Inflammation, Myofibroblast, Peripheral nerve injury, Rheumatoid arthritis, SARS-CoV-2, Wound healing,
• MeSH
• autoimunita MeSH
• autoimunitní nemoci * farmakoterapie   MeSH
• COVID-19 * MeSH
• hojení ran MeSH
• lidé MeSH
• nádorové mikroprostředí MeSH
• nádory * farmakoterapie   MeSH
• zánět MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

One of the changes brought about by Wallerian degeneration distal to nerve injury is disintegration of axonal mitochondria and consequent leakage of mitochondrial DNA (mtDNA)-the natural ligand for the toll-like receptor 9 (TLR9). RT-PCR and immunohistochemical or Western blot analyses were used to detect TLR9 mRNA and protein respectively in the lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) ipsilateral and contralateral to a sterile unilateral sciatic nerve compression or transection. The unilateral sciatic nerve lesions led to bilateral increases in levels of both TLR9 mRNA and protein not only in the lumbar but also in the remote cervical DRG compared with naive or sham-operated controls. This upregulation of TLR9 was linked to activation of the Nuclear Factor kappa B (NFκB) and nuclear translocation of the Signal Transducer and Activator of Transcription 3 (STAT3), implying innate neuronal immune reaction and a pro-regenerative state in uninjured primary sensory neurons of the cervical DRG. The relationship of TLR9 to the induction of a pro-regenerative state in the cervical DRG neurons was confirmed by the shorter lengths of regenerated axons distal to ulnar nerve crush following a previous sciatic nerve lesion and intrathecal chloroquine injection compared with control rats. The results suggest that a systemic innate immune reaction not only triggers the regenerative state of axotomized DRG neurons but also induces a pro-regenerative state further along the neural axis after unilateral nerve injury.

• Klíčová slova
• axon regeneration, compression, early endosomes, mitochondrial DNA, sciatic nerve, the endoplasmic reticulum, transection,
• MeSH
• krysa rodu Rattus MeSH
• nemoci sedacího nervu imunologie   metabolismus   patologie   terapie   MeSH
• neurony cytologie   imunologie   MeSH
• potkani Wistar MeSH
• přirozená imunita imunologie   MeSH
• spinální ganglia cytologie   MeSH
• toll-like receptor 9 genetika   metabolismus   MeSH
• transkripční faktor STAT3 genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Stat3 protein, rat MeSH Prohlížeč
• Tlr9 protein, rat MeSH Prohlížeč
• toll-like receptor 9 MeSH
• transkripční faktor STAT3 MeSH