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1.
Int J Mol Sci ; 22(15)2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34360719

RESUMO

Agonists of the Gi protein-coupled A3 adenosine receptor (A3AR) have shown important pain-relieving properties in preclinical settings of several pain models. Active as a monotherapy against chronic pain, A3AR agonists can also be used in combination with classic opioid analgesics. Their safe pharmacological profile, as shown by clinical trials for other pathologies, i.e., rheumatoid arthritis, psoriasis and fatty liver diseases, confers a realistic translational potential, thus encouraging research studies on the molecular mechanisms underpinning their antinociceptive actions. A number of pathways, involving central and peripheral mechanisms, have been proposed. Recent evidence showed that the prototypical A3AR agonist Cl-IB-MECA and the new, highly selective, A3AR agonist MRS5980 inhibit neuronal (N-type) voltage-dependent Ca2+ currents in dorsal root ganglia, a known pain-related mechanism. Other proposed pathways involve reduced cytokine production, immune cell-mediated responses, as well as reduced microglia and astrocyte activation in the spinal cord. The aim of this review is to summarize up-to-date information on A3AR in the context of pain, including cellular and molecular mechanisms underlying this effect. Based on their safety profile shown in clinical trials for other pathologies, A3AR agonists are proposed as novel, promising non-narcotic agents for pain control.


Assuntos
Agonistas do Receptor A3 de Adenosina/uso terapêutico , Sinalização do Cálcio/efeitos dos fármacos , Gânglios Espinais , Dor , Receptor A3 de Adenosina/metabolismo , Animais , Astrócitos/metabolismo , Gânglios Espinais/metabolismo , Gânglios Espinais/fisiopatologia , Humanos , Microglia/metabolismo , Dor/tratamento farmacológico , Dor/metabolismo , Dor/fisiopatologia
2.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281158

RESUMO

Thymic stromal lymphopoietin (TSLP) is a well-known cytokine for T helper 2 inflammatory responses. A nerve injury activates the neuroinflammation cascade and neuron-glia interaction in dorsal root ganglions (DRG)s, leading to neuropathic pain. Therefore, this study was to investigate the role of TSLP after nerve injury. Male Sprague-Dawley rats were divided as an experimental group with chronic constriction injury (CCI) to the sciatic nerve and a control group. The mechanical pain threshold response was determined by calibration forceps. After assessment of mechanical allodynia, the ipsilateral spinal cord, DRG, sciatic nerve and skin were harvested. Immunofluorescence staining was performed to identify cell types with various markers. Western blot analyses were performed to evaluate protein expressions. Mechanical allodynia developed after CCI and persisted for the next 14 days. Astrocyte reactions occurred and continued until day 14, too. After CCI, DRG and the sciatic nerve also had significantly increased expressions of TSLP/TSLP-R/STAT5. The TSLPR was localized to sensory neuronal endings innervating the skin. This study is the first to demonstrate that the TSLP complex and the STAT5 pathway in nerve are potential therapeutic targets because of their roles in pain regulation after nerve injury.


Assuntos
Lesões por Esmagamento/metabolismo , Citocinas/metabolismo , Neurônios/metabolismo , Animais , Constrição Patológica/metabolismo , Lesões por Esmagamento/genética , Citocinas/genética , Gânglios Espinais/metabolismo , Expressão Gênica/genética , Hiperalgesia/metabolismo , Masculino , Tecido Nervoso/metabolismo , Neuralgia/metabolismo , Neuroglia/metabolismo , Limiar da Dor , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/metabolismo , Células Receptoras Sensoriais/metabolismo
3.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203675

RESUMO

Recently, we found that the deletion of TRPC5 leads to increased inflammation and pain-related behaviour in two animal models of arthritis. (-)-Englerin A (EA), an extract from the East African plant Phyllanthus engleri has been identified as a TRPC4/5 agonist. Here, we studied whether or not EA has any anti-inflammatory and analgesic properties via TRPC4/5 in the carrageenan model of inflammation. We found that EA treatment in CD1 mice inhibited thermal hyperalgesia and mechanical allodynia in a dose-dependent manner. Furthermore, EA significantly reduced the volume of carrageenan-induced paw oedema and the mass of the treated paws. Additionally, in dorsal root ganglion (DRG) neurons cultured from WT 129S1/SvIm mice, EA induced a dose-dependent cobalt uptake that was surprisingly preserved in cultured DRG neurons from 129S1/SvIm TRPC5 KO mice. Likewise, EA-induced anti-inflammatory and analgesic effects were preserved in the carrageenan model in animals lacking TRPC5 expression or in mice treated with TRPC4/5 antagonist ML204.This study demonstrates that while EA activates a sub-population of DRG neurons, it induces a novel TRPC4/5-independent analgesic and anti-inflammatory effect in vivo. Future studies are needed to elucidate the molecular and cellular mechanisms underlying EA's anti-inflammatory and analgesic effects.


Assuntos
Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Sesquiterpenos de Guaiano/farmacologia , Canais de Cátion TRPC/metabolismo , Analgésicos/uso terapêutico , Animais , Anti-Inflamatórios/uso terapêutico , Comportamento Animal/efeitos dos fármacos , Carragenina , Células Cultivadas , Cobalto/metabolismo , Modelos Animais de Doenças , Edema/patologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Hiperalgesia/tratamento farmacológico , Inflamação/complicações , Inflamação/tratamento farmacológico , Inflamação/patologia , Masculino , Camundongos Knockout , Dor/complicações , Dor/tratamento farmacológico , Dor/patologia , Fenótipo , Células Receptoras Sensoriais/efeitos dos fármacos , Células Receptoras Sensoriais/metabolismo , Sesquiterpenos de Guaiano/uso terapêutico
4.
Int J Mol Sci ; 22(14)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34298938

RESUMO

The expression of 5-HT (serotonin) receptors (sr) was analyzed in the spinal cord and ganglia of 15 human conceptuses (5-10-weeks), and in the 9-week fetus with spina bifida. We used immunohistochemical method to detect sr-positive, apoptotic (caspase-3) and proliferating (Ki-67) cells, double immunofluorescence for co-localization with protein gene peptide (pgp) 9.5 and GFAP, as well as semiquantification and statistical measurements. Following the neurulation process, moderate (sr1 and sr2) and mild (sr3) expression characterized neuroblasts in the spinal cord and ganglia. During further development, sr1 expression gradually increased in the motoneurons, autonomic and sensory neurons, while sr2 and sr3 increased strongly in floor and roof plates. In the ganglia, sr3 expression increased during limited developmental period, while sr1 and sr2 increased throughout the investigated period. Co-expression of sr/pgp 9.5 characterized developing neurons, while sr/GFAP co-localized in the roof plate. In the spinal cord and ganglia of malformed fetus, weaker sr1 and sr2 and stronger sr3 expression accompanied morphological abnormalities. Anomalous roof plate morphology showed an excess of apoptotic and proliferating cells and increased sr3 expression. Our results indicate a human-species specific sr expression pattern, and the importance of sr1 in neuronal differentiation, and sr2 and sr3 in the control of the roof plate morphogenesis in normal and disturbed development.


Assuntos
Feto/metabolismo , Gânglios Espinais/metabolismo , Gânglios/metabolismo , Receptores de Serotonina/metabolismo , Medula Espinal/metabolismo , Disrafismo Espinal/metabolismo , Apoptose/fisiologia , Caspase 3/metabolismo , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Humanos , Antígeno Ki-67/metabolismo , Células Receptoras Sensoriais/metabolismo , Serotonina/metabolismo
5.
Nat Commun ; 12(1): 4558, 2021 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-34315904

RESUMO

Patients with advanced stage cancers frequently suffer from severe pain as a result of bone metastasis and bone destruction, for which there is no efficacious treatment. Here, using multiple mouse models of bone cancer, we report that agonists of the immune regulator STING (stimulator of interferon genes) confer remarkable protection against cancer pain, bone destruction, and local tumor burden. Repeated systemic administration of STING agonists robustly attenuates bone cancer-induced pain and improves locomotor function. Interestingly, STING agonists produce acute pain relief through direct neuronal modulation. Additionally, STING agonists protect against local bone destruction and reduce local tumor burden through modulation of osteoclast and immune cell function in the tumor microenvironment, providing long-term cancer pain relief. Finally, these in vivo effects are dependent on host-intrinsic STING and IFN-I signaling. Overall, STING activation provides unique advantages in controlling bone cancer pain through distinct and synergistic actions on nociceptors, immune cells, and osteoclasts.


Assuntos
Neoplasias Ósseas/complicações , Dor do Câncer/etiologia , Dor do Câncer/imunologia , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Analgésicos/farmacologia , Animais , Neoplasias Ósseas/sangue , Dor do Câncer/sangue , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Fêmur/diagnóstico por imagem , Fêmur/efeitos dos fármacos , Fêmur/patologia , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Proteínas de Homeodomínio/metabolismo , Hiperalgesia/complicações , Interferons/sangue , Interferons/metabolismo , Masculino , Neoplasias Mamárias Animais/complicações , Proteínas de Membrana/agonistas , Camundongos Endogâmicos C57BL , Metástase Neoplásica , Neurônios/efeitos dos fármacos , Nociceptividade/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Osteoclastos/patologia , Osteogênese/efeitos dos fármacos , Receptor de Interferon alfa e beta/metabolismo , Transdução de Sinais/efeitos dos fármacos , Carga Tumoral/efeitos dos fármacos , Microambiente Tumoral/efeitos dos fármacos , Xantonas/farmacologia
6.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281198

RESUMO

Reconstruction of nerve defects is a clinical challenge. Autologous nerve grafts as the gold standard treatment may result in an incomplete restoration of extremity function. Biosynthetic nerve conduits are studied widely, but still have limitations. Here, we reconstructed a 10 mm sciatic nerve defect in healthy rats and analyzed nerve regeneration in poly (ε-caprolactone) (PCL) conduits longitudinally divided by gold (Au) and gold-cobalt oxide (AuCoO) nanoparticles embedded in poly-propylene poly-ethylene glycol (PPEG) membranes (AuPPEG or AuCoOPPEG) and compared it with unmodified PPEG-membrane and hollow PCL conduits. After 21 days, we detected significantly better axonal outgrowth, together with higher numbers of activated Schwann cells (ATF3-labelled) and higher HSP27 expression, in reconstructed sciatic nerve and in corresponding dorsal root ganglia (DRG) in the AuPPEG and AuCoOPPEG groups; whereas the number of apoptotic Schwann cells (cleaved caspase 3-labelled) was significantly lower. Furthermore, numbers of activated and apoptotic Schwann cells in the regenerative matrix correlated with axonal outgrowth, whereas HSP27 expression in the regenerative matrix and in DRGs did not show any correlation with axonal outgrowth. We conclude that gold and cobalt-oxide nanoparticle modified membranes in conduits improve axonal outgrowth and increase the regenerative performance of conduits after nerve reconstruction.


Assuntos
Ouro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Regeneração Nervosa/efeitos dos fármacos , Nervo Isquiático/efeitos dos fármacos , Animais , Cobalto/farmacologia , Feminino , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Ouro/farmacologia , Nanopartículas Metálicas/química , Regeneração Nervosa/fisiologia , Óxidos/farmacologia , Poliésteres/química , Poliésteres/farmacologia , Polietilenoglicóis/química , Polietilenoglicóis/farmacologia , Polipropilenos/química , Polipropilenos/farmacologia , Próteses e Implantes , Ratos , Ratos Wistar , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Nervo Isquiático/metabolismo
7.
Toxicology ; 459: 152853, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34252480

RESUMO

Oxaliplatin (OXA) is a third-generation platinum drug; however, its application is greatly limited due to the severe peripheral neurotoxicity. This study aims to confirm the transport mechanism of OXA and to explore whether L-tetrahydropalmatine (L-THP) would alleviate OXA-induced peripheral neurotoxicity by selectively inhibiting these uptake transporters in vitro and in vivo. Our results revealed that organic cation transporter 2 (OCT2), organic cation/carnitine transporter 1 (OCTN1) and organic cation/carnitine transporter 2 (OCTN2) were involved in the uptake of OXA in dorsal root ganglion (DRG) neurons and mitochondria, respectively. L-THP (1-100 µM) reduced OXA (40 µM) induced cytotoxicity in MDCK-hOCT2 (Madin-Darby canine kidney, MDCK), MDCK-hOCTN1, MDCK-hOCTN2, and rat primary DRG cells, and decreased the accumulation of OXA in above cells and rat DRG mitochondria, but did not affect its efflux from MDCK-hMRP2 cells. Furthermore, Co-administration of L-THP (5-20 mg/kg for mice, 10-40 mg/kg for rats; twice a week, iv or ig) attenuated OXA (8 mg/kg for mice, 4 mg/kg for rats; twice a week, iv) induced peripheral neurotoxicity and reduced the platinum concentration in the DRG. Whereas, L-THP (1-100 µM for cells; 10-20 mg/kg for mice) did not impair the antitumour efficacy of OXA (40 µM for cells; 8 mg/kg for mice) in HT29 tumour-bearing nude mice nor in tumour cells (HT29 and SW620 cells). In conclusion, OCT2, OCTN1 and OCTN2 contribute to OXA uptake in the DRG and mitochondria. L-THP attenuates OXA-induced peripheral neurotoxicity via inhibiting OXA uptake but without impairing the antitumour efficacy of OXA. L-THP is a potential candidate drug to attenuate OXA-induced peripheral neurotoxicity.


Assuntos
Antineoplásicos/farmacocinética , Antineoplásicos/toxicidade , Alcaloides de Berberina/farmacologia , Proteínas de Transporte/antagonistas & inibidores , Gânglios Espinais/metabolismo , Mitocôndrias/metabolismo , Oxaliplatina/farmacocinética , Oxaliplatina/toxicidade , Doenças do Sistema Nervoso Periférico/induzido quimicamente , Doenças do Sistema Nervoso Periférico/prevenção & controle , Animais , Comportamento Animal/efeitos dos fármacos , Cães , Gânglios Espinais/efeitos dos fármacos , Células HEK293 , Células HT29 , Humanos , Células Madin Darby de Rim Canino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Nus , Mitocôndrias/efeitos dos fármacos , Proteínas de Transporte de Cátions Orgânicos/antagonistas & inibidores , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Transportador 2 de Cátion Orgânico/antagonistas & inibidores , Ratos , Membro 5 da Família 22 de Carreadores de Soluto/antagonistas & inibidores , Membro 5 da Família 22 de Carreadores de Soluto/metabolismo , Simportadores/antagonistas & inibidores , Simportadores/metabolismo
8.
Nat Metab ; 3(6): 762-773, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34140694

RESUMO

Chronic pain is the leading cause of disability worldwide1 and is commonly associated with comorbid disorders2. However, the role of diet in chronic pain is poorly understood. Of particular interest is the Western-style diet, enriched with ω-6 polyunsaturated fatty acids (PUFAs) that accumulate in membrane phospholipids and oxidise into pronociceptive oxylipins3,4. Here we report that mice administered an ω-6 PUFA-enriched diet develop persistent nociceptive hypersensitivities, spontaneously active and hyper-responsive glabrous afferent fibres and histologic markers of peripheral nerve damage reminiscent of a peripheral neuropathy. Linoleic and arachidonic acids accumulate in lumbar dorsal root ganglia, with increased liberation via elevated phospholipase (PLA)2 activity. Pharmacological and molecular inhibition of PLA2G7 or diet reversal with high levels of ω-3 PUFAs attenuate nociceptive behaviours, neurophysiologic abnormalities and afferent histopathology induced by high ω-6 intake. Additionally, ω-6 PUFA accumulation exacerbates allodynia observed in preclinical inflammatory and neuropathic pain models and is strongly correlated with multiple pain indices of clinical diabetic neuropathy. Collectively, these data reveal dietary enrichment with ω-6 PUFAs as a new aetiology of peripheral neuropathy and risk factor for chronic pain and implicate multiple therapeutic considerations for clinical pain management.


Assuntos
Biomarcadores , Dor Crônica/etiologia , Dor Crônica/metabolismo , Suscetibilidade a Doenças , Ácidos Graxos Ômega-6/metabolismo , Doenças do Sistema Nervoso Periférico/etiologia , Doenças do Sistema Nervoso Periférico/metabolismo , Animais , Dieta , Modelos Animais de Doenças , Ácidos Graxos Insaturados/metabolismo , Gânglios Espinais/metabolismo , Metabolismo dos Lipídeos , Camundongos , Fosfolipases A2/metabolismo , Fatores de Risco
9.
Anticancer Res ; 41(4): 1733-1744, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33813377

RESUMO

BACKGROUND/AIM: We sought to identify the mechanisms of perineural invasion in pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: We utilized in vitro cancer cell-nerve co-culture models comprising human PDAC cell lines (MIA Paca2 and PANC-1) and a dorsal root ganglion (DRG) isolated from neonatal mice. We compared gene expression profiles between cell lines with/without DRG conditioned medium (DRG-CM) using RNA-sequencing (RNA-seq). RESULTS: Migration, invasion, and neurotropism were significantly enhanced in MIA Paca2 but not in PANC-1 cells co-cultured with DRGs. Among 285 genes which showed significant differences in expression levels between cell lines in RNA-seq, we focused on Ephrin receptor A4 (EPHA4), which was upregulated in MIA Paca2 cells treated with DRG-CM. The abilities of migration, invasion, and neurotropism enhanced by DRG co-culture were abolished when EPHA4 was knocked down by siRNA in MIA Paca2 cells. CONCLUSION: EPHA4 can be a potential target gene to regulate perineural invasion in PDAC cells.


Assuntos
Carcinoma Ductal Pancreático/metabolismo , Movimento Celular , Gânglios Espinais/metabolismo , Neoplasias Pancreáticas/metabolismo , Comunicação Parácrina , Receptor EphA4/metabolismo , Animais , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Técnicas de Cocultura , Regulação Neoplásica da Expressão Gênica , Humanos , Camundongos Endogâmicos ICR , Invasividade Neoplásica , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Receptor EphA4/genética , Transdução de Sinais
10.
Int J Mol Sci ; 22(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806699

RESUMO

Nociceptors sense hazards via plasmalemmal cation channels, including transient receptor potential vanilloid 1 (TRPV1). Nerve growth factor (NGF) sensitises TRPV1 to capsaicin (CAPS), modulates nociceptor excitability and induces thermal hyperalgesia, but cellular mechanisms remain unclear. Confocal microscopy was used to image changes in intracellular Ca2+ concentration ([Ca2+]i) across neuronal populations in dorsal root ganglia (DRG) explants from pirt-GCaMP3 adult mice, which express a fluorescent reporter in their sensory neurons. Raised [Ca2+]i was detected in 84 neurons of three DRG explants exposed to NGF (100 ng/mL) and most (96%) of these were also excited by 1 µM CAPS. NGF elevated [Ca2+]i in about one-third of the neurons stimulated by 1 µM CAPS, whether applied before or after the latter. In neurons excitable by NGF, CAPS-evoked [Ca2+]i signals appeared significantly sooner (e.g., respective lags of 1.0 ± 0.1 and 1.9 ± 0.1 min), were much (>30%) brighter and lasted longer (6.6 ± 0.4 vs. 3.9 ± 0.2 min) relative to those non-responsive to the neurotrophin. CAPS tachyphylaxis lowered signal intensity by ~60% but was largely prevented by NGF. Increasing CAPS from 1 to 10 µM nearly doubled the number of cells activated but only modestly increased the amount co-activated by NGF. In conclusion, a sub-population of the CAPS-sensitive neurons in adult mouse DRG that can be excited by NGF is more sensitive to CAPS, responds with stronger signals and is further sensitised by transient exposure to the neurotrophin.


Assuntos
Sinalização do Cálcio/efeitos dos fármacos , Cálcio/metabolismo , Capsaicina/farmacologia , Gânglios Espinais/efeitos dos fármacos , Fator de Crescimento Neural/farmacologia , Neurônios/efeitos dos fármacos , Nociceptividade/efeitos dos fármacos , Animais , Feminino , Gânglios Espinais/metabolismo , Hiperalgesia/metabolismo , Masculino , Camundongos , Fatores de Crescimento Neural/metabolismo , Neurônios/metabolismo , Nociceptores/metabolismo , Transdução de Sinais/efeitos dos fármacos , Canais de Cátion TRPV/metabolismo
11.
Int J Mol Sci ; 22(7)2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33806000

RESUMO

Pharmacotherapy of neuropathic pain is still challenging. Our earlier work indicated an analgesic effect of dimethyl trisulfide (DMTS), which was mediated by somatostatin released from nociceptor nerve endings acting on SST4 receptors. Somatostatin release occurred due to TRPA1 ion channel activation. In the present study, we investigated the effect of DMTS in neuropathic pain evoked by partial ligation of the sciatic nerve in mice. Expression of the mRNA of Trpa1 in murine dorsal-root-ganglion neurons was detected by RNAscope. Involvement of TRPA1 ion channels and SST4 receptors was tested with gene-deleted animals. Macrophage activity at the site of the nerve lesion was determined by lucigenin bioluminescence. Density and activation of microglia in the spinal cord dorsal horn was verified by immunohistochemistry and image analysis. Trpa1 mRNA is expressed in peptidergic and non-peptidergic neurons in the dorsal root ganglion. DMTS ameliorated neuropathic pain in Trpa1 and Sstr4 WT mice, but not in KO ones. DMTS had no effect on macrophage activity around the damaged nerve. Microglial density in the dorsal horn was reduced by DMTS independently from TRPA1. No effect on microglial activation was detected. DMTS might offer a novel therapeutic opportunity in the complementary treatment of neuropathic pain.


Assuntos
Neuralgia/tratamento farmacológico , Sulfetos/farmacologia , Canal de Cátion TRPA1/metabolismo , Animais , Gânglios Espinais/metabolismo , Hiperalgesia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/metabolismo , Microscopia Confocal , RNA Mensageiro/metabolismo , Nervo Isquiático/patologia , Somatostatina/metabolismo
12.
Int J Mol Sci ; 22(7)2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33807167

RESUMO

Atractylodin (ATR) is a bioactive component found in dried rhizomes of Atractylodes lancea (AL) De Candolle. Although AL has accumulated empirical evidence for the treatment of pain, the molecular mechanism underlying the anti-pain effect of ATR remains unclear. In this study, we found that ATR increases transient receptor potential ankyrin-1 (TRPA1) single-channel activity in hTRPA1 expressing HEK293 cells. A bath application of ATR produced a long-lasting calcium response, and the response was completely diminished in the dorsal root ganglion neurons of TRPA1 knockout mice. Intraplantar injection of ATR evoked moderate and prolonged nociceptive behavior compared to the injection of allyl isothiocyanate (AITC). Systemic application of ATR inhibited AITC-induced nociceptive responses in a dose-dependent manner. Co-application of ATR and QX-314 increased the noxious heat threshold compared with AITC in vivo. Collectively, we concluded that ATR is a unique agonist of TRPA1 channels, which produces long-lasting channel activation. Our results indicated ATR-mediated anti-nociceptive effect through the desensitization of TRPA1-expressing nociceptors.


Assuntos
Furanos/metabolismo , Furanos/farmacologia , Canal de Cátion TRPA1/metabolismo , Analgésicos/metabolismo , Analgésicos/farmacologia , Animais , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Gânglios Espinais/metabolismo , Células HEK293 , Humanos , Isotiocianatos/farmacologia , Lidocaína/análogos & derivados , Lidocaína/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurônios/metabolismo , Nociceptividade/efeitos dos fármacos , Nociceptores/metabolismo , Dor/tratamento farmacológico , Ratos , Ratos Sprague-Dawley , Canal de Cátion TRPA1/agonistas , Canal de Cátion TRPA1/efeitos dos fármacos , Canais de Cátion TRPC/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo
13.
Int J Mol Sci ; 22(6)2021 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-33804711

RESUMO

The primary cilium plays a pivotal role during the embryonic development of vertebrates. It acts as a somatic signaling hub for specific pathways, such as Sonic Hedgehog signaling. In humans, mutations in genes that cause dysregulation of ciliogenesis or ciliary function lead to severe developmental disorders called ciliopathies. Beyond its role in early morphogenesis, growing evidence points towards an essential function of the primary cilium in neural circuit formation in the central nervous system. However, very little is known about a potential role in the formation of the peripheral nervous system. Here, we investigate the presence of the primary cilium in neural crest cells and their derivatives in the trunk of developing chicken embryos in vivo. We found that neural crest cells, sensory neurons, and boundary cap cells all bear a primary cilium during key stages of early peripheral nervous system formation. Moreover, we describe differences in the ciliation of neuronal cultures of different populations from the peripheral and central nervous systems. Our results offer a framework for further in vivo and in vitro investigations on specific roles that the primary cilium might play during peripheral nervous system formation.


Assuntos
Cílios/fisiologia , Sistema Nervoso Periférico/fisiologia , Biomarcadores , Movimento Celular , Imunofluorescência , Gânglios Espinais/citologia , Gânglios Espinais/metabolismo , Humanos , Crista Neural/metabolismo , Neurônios/metabolismo , Organogênese/genética
15.
Nat Commun ; 12(1): 1955, 2021 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-33782410

RESUMO

p62/SQSTM1 is known to act as a key mediator in the selective autophagy of protein aggregates, or aggrephagy, by steering ubiquitinated protein aggregates towards the autophagy pathway. Here, we use a yeast two-hybrid screen to identify the prefoldin-like chaperone UXT as an interacting protein of p62. We show that UXT can bind to protein aggregates as well as the LB domain of p62, and, possibly by forming an oligomer, increase p62 clustering for its efficient targeting to protein aggregates, thereby promoting the formation of the p62 body and clearance of its cargo via autophagy. We also find that ectopic expression of human UXT delays SOD1(A4V)-induced degeneration of motor neurons in a Xenopus model system, and that specific disruption of the interaction between UXT and p62 suppresses UXT-mediated protection. Together, these results indicate that UXT functions as an autophagy adaptor of p62-dependent aggrephagy. Furthermore, our study illustrates a cooperative relationship between molecular chaperones and the aggrephagy machinery that efficiently removes misfolded protein aggregates.


Assuntos
Autofagia/genética , Proteínas de Ciclo Celular/genética , Chaperonas Moleculares/genética , Agregados Proteicos , Proteína Sequestossoma-1/genética , Superóxido Dismutase-1/genética , Animais , Autofagia/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Gânglios Espinais/citologia , Gânglios Espinais/metabolismo , Regulação da Expressão Gênica , Genes Reporter , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Células HeLa , Humanos , Leupeptinas/farmacologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Chaperonas Moleculares/metabolismo , Neurônios Motores/citologia , Neurônios Motores/efeitos dos fármacos , Neurônios Motores/metabolismo , Cultura Primária de Células , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Agregados Proteicos/efeitos dos fármacos , Dobramento de Proteína/efeitos dos fármacos , Proteína Sequestossoma-1/metabolismo , Transdução de Sinais , Superóxido Dismutase-1/metabolismo , Transgenes , Xenopus laevis
16.
PLoS One ; 16(3): e0246924, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33657119

RESUMO

Cultured sensory neurons can exhibit complex activity patterns following stimulation in terms of increased excitability and interconnected responses of multiple neurons. Although these complex activity patterns suggest a network-like configuration, research so far had little interest in synaptic network formation ability of the sensory neurons. To identify interaction profiles of Dorsal Root Ganglia (DRG) neurons and explore their putative connectivity, we developed an in vitro experimental approach. A double transgenic mouse model, expressing genetically encoded calcium indicator (GECI) in their glutamatergic neurons, was produced. Dissociated DRG cultures from adult mice were prepared with a serum-free protocol and no additional growth factors or cytokines were utilized for neuronal sensitization. DRG neurons were grown on microelectrode arrays (MEA) to induce stimulus-evoked activity with a modality-free stimulation strategy. With an almost single-cell level electrical stimulation, spontaneous and evoked activity of GCaMP6s expressing neurons were detected under confocal microscope. Typical responses were analyzed, and correlated calcium events were detected across individual DRG neurons. Next, correlated responses were successfully blocked by glutamatergic receptor antagonists, which indicated functional synaptic coupling. Immunostaining confirmed the presence of synapses mainly in the axonal terminals, axon-soma junctions and axon-axon intersection sites. Concisely, the results presented here illustrate a new type of neuron-to-neuron interaction in cultured DRG neurons conducted through synapses. The developed assay can be a valuable tool to analyze individual and collective responses of the cultured sensory neurons.


Assuntos
Técnicas de Cultura de Células/métodos , Gânglios Espinais/citologia , Sinaptofisina/metabolismo , Proteína Vesicular 2 de Transporte de Glutamato/genética , Animais , Comunicação Celular , Células Cultivadas , Estimulação Elétrica , Gânglios Espinais/metabolismo , Camundongos , Camundongos Transgênicos , Receptores de Glutamato/metabolismo
17.
J Anat ; 239(1): 111-124, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33730389

RESUMO

Chronic postsurgical pain (CPSP) is a common complication after surgery; however, the underlying mechanisms of CPSP are poorly understood. As one of the most important inflammatory pathways, the Toll-like receptor 4/nuclear factor-kappa B (TLR4/NF-κB) signaling pathway plays an important role in chronic pain. However, the precise role of the TLR4/NF-κB signaling pathway in CPSP remains unclear. In the present study, we established a rat model of CPSP induced by skin/muscle incision and retraction (SMIR) and verified the effects and mechanisms of central and peripheral TLR4 and NF-κB on hyperalgesia in SMIR rats. The results showed that TLR4 expression was increased in both the spinal dorsal horn and dorsal root ganglia (DRGs) of SMIR rats. However, the TLR4 expression pattern in the spinal cord was different from that in DRGs. In the spinal cord, TLR4 was expressed in both neurons and microglia, whereas it was expressed in neurons but not in satellite glial cells in DRGs. Further results demonstrate that the central and peripheral TLR4/NF-κB signaling pathway is involved in the SMIR-induced CPSP by different mechanisms. In the peripheral nervous system, we revealed that the TLR4/NF-κB signaling pathway induced upregulation of voltage-gated sodium channel 1.7 (Nav1.7) in DRGs, triggering peripheral hyperalgesia in SMIR-induced CPSP. In the central nervous system, the TLR4/NF-κB signaling pathway participated in SMIR-induced CPSP by activating microglia in the spinal cord. Ultimately, our findings demonstrated that activation of the peripheral and central TLR4/NF-κB signaling pathway involved in the development of SMIR-induced CPSP.


Assuntos
Dor Crônica/metabolismo , Microglia/metabolismo , Dor Pós-Operatória/metabolismo , Medula Espinal/metabolismo , Receptor 4 Toll-Like/metabolismo , Animais , Antígeno CD11b/metabolismo , Gânglios Espinais/metabolismo , Hiperalgesia/metabolismo , Masculino , Canal de Sódio Disparado por Voltagem NAV1.7/metabolismo , NF-kappa B/metabolismo , Ratos Sprague-Dawley , Regulação para Cima
18.
Photochem Photobiol Sci ; 20(2): 293-301, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33721255

RESUMO

There is no effective treatment to halt peripheral nervous system damage in diabetic peripheral neuropathy. Mitochondria have been at the center of discussions as important factors in the development of neuropathy in diabetes. Photobiomodulation has been gaining clinical acceptance as it shows beneficial effects on a variety of nervous system disorders. In this study, the effects of photobiomodulation (904 nm, 45 mW, 6.23 J/cm2, 0.13 cm2, 60 ns pulsed time) on mitochondrial dynamics were evaluated in an adult male rat experimental model of streptozotocin-induced type 1 diabetes. Results presented here indicate that photobiomodulation could have an important role in preventing or reversing mitochondrial dynamics dysfunction in the course of peripheral nervous system damage in diabetic peripheral neuropathy. Photobiomodulation showed its effects on modulating the protein expression of mitofusin 2 and dynamin-related protein 1 in the sciatic nerve and in the dorsal root ganglia neurons of streptozotocin-induced type 1 diabetes in rats.


Assuntos
Gânglios Espinais/efeitos da radiação , Lasers Semicondutores , Dinâmica Mitocondrial/efeitos da radiação , Nervo Isquiático/efeitos da radiação , Animais , Glicemia/análise , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/patologia , Gânglios Espinais/metabolismo , Masculino , Ratos , Ratos Wistar , Nervo Isquiático/metabolismo , Estreptozocina/toxicidade
19.
Biomolecules ; 11(2)2021 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-33672050

RESUMO

Although diabetic polyneuropathy (DPN) is a frequent diabetic complication, no effective therapeutic approach has been established. Glucagon is a crucial hormone for glucose homeostasis but has pleiotropic effects, including neuroprotective effects in the central nervous system. However, the importance of glucagon in the peripheral nervous system (PNS) has not been clarified. Here, we hypothesized that glucagon might have a neuroprotective function in the PNS. The immortalized rat dorsal root ganglion (DRG) neuronal cell line 50B11 was treated with methylglyoxal (MG) to mimic an in vitro DPN model. The cells were cultured with or without glucagon or MG. Neurotoxicity, survival, apoptosis, neurite projection, cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA) were examined. Glucagon had no cytotoxicity and rescued the cells from neurotoxicity. Cell survival was increased by glucagon. The ratio of apoptotic cells, which was increased by MG, was reduced by glucagon. Neurite outgrowth was accelerated in glucagon-treated cells. Cyclic AMP and PKA accumulated in the cells after glucagon stimulation. In conclusion, glucagon protected the DRG neuronal cells from MG-induced cellular stress. The cAMP/PKA pathway may have significant roles in those protective effects of glucagon. Glucagon may be a potential target for the treatment of DPN.


Assuntos
Neuropatias Diabéticas/metabolismo , Glucagon/química , Neurônios/metabolismo , Sistema Nervoso Periférico/metabolismo , Aldeído Pirúvico/química , Animais , Apoptose , Linhagem Celular , Sobrevivência Celular , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Gânglios Espinais/metabolismo , Glucagon/metabolismo , Mitocôndrias/metabolismo , Neuritos/metabolismo , Ratos , Espécies Reativas de Oxigênio
20.
Eur J Pharmacol ; 899: 174034, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33727056

RESUMO

Glycine receptor is one of the chloride-permeable ion channels composed of combinations of four α subunits and one ß subunit. In adult spinal cord, the glycine receptor α1 subunit is crucial for the generation of inhibitory neurotransmission. The reduced glycinergic inhibition is regarded as one of the key spinal mechanisms underlying pathological pain symptoms. However, the expression and function of glycine receptors in the peripheral system are largely unknown as yet. Here we found that glycine receptor α1 subunit was prevalent in the dorsal root ganglia (DRG) neurons as well as in the sciatic nerves of adult mice. Intraganglionar or intraplantar injection of glycine receptor antagonist strychnine caused the hypersensitivity to mechanical, thermal and cold stimuli, suggesting the functional importance of peripheral glycine receptors in the control of nociceptive signal transmission. Our data showed that peripheral inflammation induced by formalin decreased the expression of glycine receptor α1 subunit on the plasma membrane of DRG neurons, which was attributed to the activation of protein kinase C signaling. Intraplantar application of glycine receptor agonist glycine or positive modulator divalent zinc ion alleviated the first-phase painful behaviors induced by formalin. These data suggested that peripheral glycine receptor might serve as an effective target for pain therapy.


Assuntos
Gânglios Espinais/metabolismo , Inibição Neural , Dor Nociceptiva/metabolismo , Receptores de Glicina/metabolismo , Analgésicos/farmacologia , Animais , Comportamento Animal , Modelos Animais de Doenças , Formaldeído , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/fisiopatologia , Glicinérgicos/farmacologia , Masculino , Camundongos , Atividade Motora , Inibição Neural/efeitos dos fármacos , Nociceptividade , Dor Nociceptiva/induzido quimicamente , Dor Nociceptiva/fisiopatologia , Dor Nociceptiva/prevenção & controle , Limiar da Dor/efeitos dos fármacos , Proteína Quinase C/metabolismo , Receptores de Glicina/antagonistas & inibidores , Transdução de Sinais
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