RESUMEN
Lysophosphatidic acids (LPAs) evoke nociception and itch in mice and humans. In this study, we assessed the signaling paths. Hydroxychloroquine was injected intradermally to evoke itch in mice, which evoked an increase of LPAs in the skin and in the thalamus, suggesting that peripheral and central LPA receptors (LPARs) were involved in HCQ-evoked pruriception. To unravel the signaling paths, we assessed the localization of candidate genes and itching behavior in knockout models addressing LPAR5, LPAR2, autotaxin/ENPP2 and the lysophospholipid phosphatases, as well as the plasticity-related genes Prg1/LPPR4 and Prg2/LPPR3. LacZ reporter studies and RNAscope revealed LPAR5 in neurons of the dorsal root ganglia (DRGs) and in skin keratinocytes, LPAR2 in cortical and thalamic neurons, and Prg1 in neuronal structures of the dorsal horn, thalamus and SSC. HCQ-evoked scratching behavior was reduced in sensory neuron-specific Advillin-LPAR5-/- mice (peripheral) but increased in LPAR2-/- and Prg1-/- mice (central), and it was not affected by deficiency of glial autotaxin (GFAP-ENPP2-/-) or Prg2 (PRG2-/-). Heat and mechanical nociception were not affected by any of the genotypes. The behavior suggested that HCQ-mediated itch involves the activation of peripheral LPAR5, which was supported by reduced itch upon treatment with an LPAR5 antagonist and autotaxin inhibitor. Further, HCQ-evoked calcium fluxes were reduced in primary sensory neurons of Advillin-LPAR5-/- mice. The results suggest that LPA-mediated itch is primarily mediated via peripheral LPAR5, suggesting that a topical LPAR5 blocker might suppress "non-histaminergic" itch.
Asunto(s)
Hidroxicloroquina , Ratones Noqueados , Prurito , Receptores del Ácido Lisofosfatídico , Animales , Receptores del Ácido Lisofosfatídico/metabolismo , Receptores del Ácido Lisofosfatídico/genética , Prurito/inducido químicamente , Prurito/metabolismo , Prurito/genética , Prurito/tratamiento farmacológico , Ratones , Hidroxicloroquina/farmacología , Ganglios Espinales/metabolismo , Ganglios Espinales/efectos de los fármacos , Masculino , Hidrolasas Diéster Fosfóricas/metabolismo , Hidrolasas Diéster Fosfóricas/genética , Lisofosfolípidos/metabolismo , Ratones Endogámicos C57BL , Transducción de Señal/efectos de los fármacosRESUMEN
Dry skin is common to many pruritic diseases and is difficult to improve with oral traditional antihistamines. Recently, increasing evidence indicated that histamine H4 receptor (H4R) plays an important role in the occurrence and development of pruritus. Extracellular signal-regulated kinase (ERK) phosphorylation activation in the spinal cord mediates histamine-induced acute and choric itch. However, whether the histamine H4 receptor regulates ERK activation in the dry skin itch remains unclear. In the study, we explore the role of the histamine H4 receptor and p-ERK in the spinal cord in a dry skin mouse model induced by acetone-ether-water (AEW). q-PCR, Western blot, pharmacology and immunofluorescence were applied in the study. We established a dry skin itch model by repeated application of AEW on the nape of neck in mice. The AEW mice showed typically dry skin histological change and persistent spontaneous scratching behaviour. Histamine H4 receptor, instead of histamine H1 receptor, mediated spontaneous scratching behaviour in AEW mice. Moreover, c-Fos and p-ERK expression in the spinal cord neurons were increased and co-labelled with GRPR-positive neurons in AEW mice. Furthermore, H4R agonist 4-methyhistamine dihydrochloride (4-MH)induced itch. Both 4-MH-induced itch and the spontaneous itch in AEW mice were blocked by p-ERK inhibitor U0126. Finally, intrathecal H4R receptor antagonist JNJ7777120 inhibited spinal p-ERK expression in AEW mice. Our results indicated that spinal H4R mediates itch via ERK activation in the AEW-induced dry skin mice.
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Acetona , Quinasas MAP Reguladas por Señal Extracelular , Prurito , Receptores Histamínicos H4 , Médula Espinal , Animales , Prurito/inducido químicamente , Prurito/metabolismo , Receptores Histamínicos H4/metabolismo , Ratones , Médula Espinal/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Masculino , Acetona/farmacología , Agua , Éter , Modelos Animales de Enfermedad , Fosforilación , Indoles/farmacología , Butadienos/farmacología , Piperazinas/farmacología , Nitrilos/farmacología , Piel/metabolismo , Enfermedad Crónica , Metilhistaminas , Proteínas Proto-Oncogénicas c-fos/metabolismo , Ratones Endogámicos C57BLRESUMEN
Irritant contact dermatitis (ICD) is a nonspecific skin inflammation caused by irritants, leading to itch and pain. We tested whether differential responses to histamine-dependent and -independent pruritogens can be evoked in ICD induced by sodium lauryl sulfate (SLS). An ICD mouse model was established with 5% SLS in acetone versus a vehicle topically applied for 24 h to the cheek. Site-directed itch- and pain-like behaviors, occurring spontaneously and in response to mechanical, thermal, and chemical stimuli (histamine, ß-alanine, BAM8-22, and bradykinin) applied to the cheek, were recorded before (day 0) and after irritant removal (days 1, 2, 3, and 4). Skin inflammation was assessed through visual scoring, ultrasound, and measurements of skin thickness. SLS-treated mice exhibited hyperalgesia-like behavior in response to mechanical and heat stimuli on day 1 compared to the controls. SLS mice exhibited more spontaneous wipes (pain) but not scratching bouts (itch) on day 1. Pruritogen injections caused more scratching but not wiping in SLS-treated mice compared to the controls. Only bradykinin increased wiping behavior compared to saline. SLS-treated mice developed noticeable erythema, scaling, and increased skin thickness on days 1 and 2. SLS induced cutaneous inflammation and behavioral signs of spontaneous pain and itching, hyperalgesia to mechanical and heat stimuli and a chemical algogen, and enhanced itch response to pruritogens. These sensory reactions preceded the inflammation peak and lasted up to two days.
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Dermatitis Irritante , Modelos Animales de Enfermedad , Dolor , Prurito , Dodecil Sulfato de Sodio , Animales , Dodecil Sulfato de Sodio/efectos adversos , Prurito/inducido químicamente , Ratones , Dermatitis Irritante/etiología , Dermatitis Irritante/patología , Dermatitis Irritante/fisiopatología , Dolor/inducido químicamente , Dolor/fisiopatología , Masculino , Hiperalgesia/inducido químicamente , Piel/efectos de los fármacos , Piel/patología , Piel/metabolismo , Histamina , Irritantes/toxicidad , Bradiquinina/farmacología , Conducta Animal/efectos de los fármacosRESUMEN
Pruritus is often accompanied with bacterial infections, but the underlying mechanism is not fully understood. Although previous studies revealed that lipopolysaccharides (LPS) could directly activate TRPV4 channel and TRPV4 is involved in the generation of both acute itch and chronic itch, whether and how LPS affects TRPV4-mediated itch sensation remains unclear. Here, we showed that LPS-mediated TRPV4 sensitization exacerbated GSK101-induced scratching behaviour in mice. Moreover, this effect was compromised in TLR4-knockout mice, suggesting LPS acted through a TLR4-dependent mechanism. Mechanistically, LPS enhanced GSK101-evoked calcium influx in mouse ear skin cells and HEK293T cells transfected with TRPV4. Further, LPS sensitized TRPV4 channel through the intracellular TLR4-PI3K-AKT signalling. In summary, our study found a modulatory role of LPS in TRPV4 function and highlighted the TLR4-TRPV4 interaction in itch signal amplification.
Asunto(s)
Lipopolisacáridos , Fosfatidilinositol 3-Quinasas , Prurito , Transducción de Señal , Canales Catiónicos TRPV , Receptor Toll-Like 4 , Canales Catiónicos TRPV/metabolismo , Canales Catiónicos TRPV/genética , Animales , Receptor Toll-Like 4/metabolismo , Prurito/metabolismo , Prurito/inducido químicamente , Prurito/patología , Lipopolisacáridos/farmacología , Humanos , Ratones , Células HEK293 , Fosfatidilinositol 3-Quinasas/metabolismo , Ratones Noqueados , Ratones Endogámicos C57BL , Masculino , Calcio/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismoRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Artemisia argyi Levl.et Vant. have a long history of being used to treat skin diseases such as pruritus and dermatitis in China, but the therapeutic effect on allergic contact dermatitis (ACD) is still unclear. AIM OF THE STUDY: To investigate the effect and molecular mechanisms of the volatile oil of A. argyi leaves (abbreviated as 'AO') in the treatment of ACD. MATERIALS AND METHODS: The main components in AO were analyzed using GC-MS. The effect of AO on channel currents in hTRPA1-transfected HEK293T cells was studied by whole-cell patch clamp. Subsequently, chloroquine-evoked acute itch and squaraine dibutyl ester (SADBE)-induced ACD chronic itch model was established to evaluate the antipruritic effect through counting scratching behavior, and the anti-inflammatory effects on ACD mice were measured using histological analysis. Meanwhile, the changes of CGRP, the infiltration of nerve fibers and the recruitment of dendritic cells, the expression of Il-23 and Il-17 mRNA in skin lesions, the phosphorylation of ERK and p38 in dorsal root ganglion (DRG), were evaluated by molecular biological methods. Then the inhibitory effect of AO on AITC- or SADBE-activated TRPA1 channels in primary DRG neurons of C57BL/6, Trpa1-/- or Trpv1-/- mice was elucidated by Ca2+ imaging and immunofluorescence. RESULTS: AO treatment inhibited the activation of TRPA1 in HEK293T cells and alleviated acute itch caused by chloroquine, but this effect was lacking in Trpa1-/- mice. Furthermore, administration of AO attenuated scratching behavior in SADBE-induced ACD mice. AO also inhibited the increase of nerve fibers and recruitment of dendritic cells, and down-regulated the expression of CGRP and the levels of Il-23 and Il-17 mRNA. Meanwhile, AO reduced the expression of p-p38 and p-ERK in the lesioned skin and DRG of SADBE-induced ACD mice. Additionally, AO blocked the activation of TRPA1 channels and decreased the levels of CGRP, p-p38, and p-ERK in DRG neurons. CONCLUSION: AO could inhibit TRPA1 channels in sensory neurons, thereby reducing the release of CGRP and exerting anti-pruritic and anti-inflammatory effect. These findings also provide a new strategy for exploring the role of A. argyi in treating ACD.
Asunto(s)
Artemisia , Péptido Relacionado con Gen de Calcitonina , Dermatitis Alérgica por Contacto , Ratones Endogámicos C57BL , Aceites Volátiles , Transducción de Señal , Canal Catiónico TRPA1 , Animales , Canal Catiónico TRPA1/metabolismo , Humanos , Péptido Relacionado con Gen de Calcitonina/metabolismo , Péptido Relacionado con Gen de Calcitonina/genética , Artemisia/química , Células HEK293 , Transducción de Señal/efectos de los fármacos , Ratones , Masculino , Dermatitis Alérgica por Contacto/tratamiento farmacológico , Dermatitis Alérgica por Contacto/metabolismo , Aceites Volátiles/farmacología , Prurito/tratamiento farmacológico , Prurito/inducido químicamente , Ratones Noqueados , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/metabolismo , Hojas de la Planta/química , Modelos Animales de Enfermedad , Antipruriginosos/farmacología , Antipruriginosos/uso terapéuticoRESUMEN
Cadaverine is an endogenous metabolite produced by the gut microbiome with various activity in physiological and pathological conditions. However, whether cadaverine regulates pain or itch remains unclear. In this study, we first found that cadaverine may bind to histamine 4 receptor (H4R) with higher docking energy score using molecular docking simulations, suggesting cadaverine may act as an endogenous ligand for H4R. We subsequently found intradermal injection of cadaverine into the nape or cheek of mice induces a dose-dependent scratching response in mice, which was suppressed by a selective H4R antagonist JNJ-7777120, transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine and PLC inhibitor U73122, but not H1R antagonist or TRPA1 antagonist or TRPV4 antagonist. Consistently, cadaverine-induced itch was abolished in Trpv1-/- but not Trpa1-/- mice. Pharmacological analysis indicated that mast cells and opioid receptors were also involved in cadaverine-induced itch in mice. scRNA-Seq data analysis showed that H4R and TRPV1 are mainly co-expressed on NP2, NP3 and PEP1 DRG neurons. Calcium imaging analysis showed that cadaverine perfusion enhanced calcium influx in the dissociated dorsal root ganglion (DRG) neurons, which was suppressed by JNJ-7777120 and capsazepine, as well as in the DRG neurons from Trpv1-/- mice. Patch-clamp recordings found that cadaverine perfusion significantly increased the excitability of small diameter DRG neurons, and JNJ-7777120 abolished this effect, indicating involvement of H4R. Together, these results provide evidences that cadaverine is a novel endogenous pruritogens, which activates H4R/TRPV1 signaling pathways in the primary sensory neurons.
Asunto(s)
Cadaverina , Ganglios Espinales , Ratones Endogámicos C57BL , Prurito , Canales Catiónicos TRPV , Animales , Prurito/metabolismo , Prurito/inducido químicamente , Canales Catiónicos TRPV/metabolismo , Ganglios Espinales/metabolismo , Ganglios Espinales/efectos de los fármacos , Masculino , Cadaverina/análogos & derivados , Cadaverina/farmacología , Cadaverina/metabolismo , Ratones , Ratones Noqueados , Humanos , Mastocitos/metabolismo , Mastocitos/efectos de los fármacos , Canal Catiónico TRPA1/metabolismo , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Receptores Acoplados a Proteínas G/metabolismo , Capsaicina/análogos & derivadosAsunto(s)
Fármacos Dermatológicos , Isotretinoína , Prurito , Humanos , Prurito/inducido químicamente , Prurito/tratamiento farmacológico , Isotretinoína/efectos adversos , Fármacos Dermatológicos/efectos adversos , Masculino , Femenino , Acné Vulgar/tratamiento farmacológico , Adulto , Antagonistas de los Receptores Histamínicos/uso terapéutico , Resultado del Tratamiento , Adolescente , Adulto JovenRESUMEN
Itch, a common somatic sensation, serves as a crucial protective system. Recent studies have unraveled the neural mechanisms of itch at peripheral, spinal cord as well as cerebral levels. However, a comprehensive understanding of the central mechanism governing itch transmission and regulation remains elusive. Here, we report the role of the medial septum (MS), an integral component of the basal forebrain, in modulating the acute itch processing. The increases in c-Fos+ neurons and calcium signals within the MS during acute itch processing were observed. Pharmacogenetic activation manipulation of global MS neurons suppressed the scratching behaviors induced by chloroquine or compound 48/80. Microinjection of GABA into the MS or pharmacogenetic inhibition of non-GABAergic neurons markedly suppressed chloroquine-induced scratching behaviors. Pharmacogenetic activation of the MS-ACC GABAergic pathway attenuated chloroquine-induced acute itch. Hence, our findings reveal that MS has a regulatory role in the chloroquine-induced acute itch through local increased GABA to inhibit non-GABAergic neurons and the activation of MS-ACC GABAergic pathway.
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Cloroquina , Giro del Cíngulo , Prurito , Ácido gamma-Aminobutírico , Cloroquina/farmacología , Animales , Prurito/inducido químicamente , Prurito/metabolismo , Prurito/tratamiento farmacológico , Masculino , Ácido gamma-Aminobutírico/metabolismo , Giro del Cíngulo/metabolismo , Giro del Cíngulo/efectos de los fármacos , Neuronas GABAérgicas/metabolismo , Neuronas GABAérgicas/efectos de los fármacos , Ratones Endogámicos C57BL , Ratones , Núcleos Septales/metabolismo , Núcleos Septales/efectos de los fármacosRESUMEN
The phosphate modification of drugs is a common chemical strategy to increase solubility and allow for parenteral administration. Unfortunately, phosphate modifications often elicit treatment- or dose-limiting pruritus through an unknown mechanism. Using unbiased high-throughput drug screens, we identified the Mas-related G protein-coupled receptor X4 (MRGPRX4), a primate-specific, sensory neuron receptor previously implicated in itch, as a potential target for phosphate-modified compounds. Using both Gq-mediated calcium mobilization and G protein-independent GPCR assays, we found that phosphate-modified compounds potently activate MRGPRX4. Furthermore, a humanized mouse model expressing MRGPRX4 in sensory neurons exhibited robust phosphomonoester prodrug-evoked itch. To characterize and confirm this interaction, we further determined the structure of MRGPRX4 in complex with a phosphate-modified drug through single-particle cryo-electron microscopy (cryo-EM) and identified critical amino acid residues responsible for the binding of the phosphate group. Together, these findings explain how phosphorylated drugs can elicit treatment-limiting itch and identify MRGPRX4 as a potential therapeutic target to suppress itch and to guide future drug design.
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Modelos Animales de Enfermedad , Prurito , Receptores Acoplados a Proteínas G , Animales , Prurito/metabolismo , Prurito/inducido químicamente , Prurito/patología , Prurito/tratamiento farmacológico , Humanos , Receptores Acoplados a Proteínas G/metabolismo , Ratones , Células HEK293 , Fosforilación/efectos de los fármacos , Fosfatos/metabolismo , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/efectos de los fármacos , Profármacos/farmacología , Microscopía por CrioelectrónRESUMEN
BACKGROUND: Pruritus, or itching, is a distressing symptom associated with various dermatological and systemic diseases. L-carnitine (ßeta hydroxy-γ-tri methyl amino-butyric acid), is a naturally occurring substance, it controls numerous physiological processes. The present research aims to identify L-carnitine for its anti-pruritic effect via nitric oxide-dependent mechanism. METHODS: Chloroquine-induced pruritus serves as an experimental model to investigate possible therapeutic interventions. In this study, we evaluated the efficacy of L-carnitine in combating oxidative stress, nitric oxide, and inflammatory cytokines in a chloroquine-induced pruritus model. RESULTS: L-carnitine treatment significantly reduced scratching behavior compared to the disease group (***P < 0.001 vs. chloroquine group), indicating its antipruritic potential. The markers of oxidative stress, GST, GSH, Catalase, and LPO were dysregulated in the disease model, but administration of L-carnitine restored GST, GSH, and Catalase levels and decreased LPO levels (***P < 0.001 vs. chloroquine group), thereby alleviating oxidative stress. L-carnitine also reduced nitric oxide synthase (NOS) activity, suggesting that it modulates nitric oxide signaling pathways involved in pruritus. In addition, L-carnitine lowered levels of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), inflammatory marker nuclear factor kappa B (p-NFκB) and also reduces an inflammatory enzyme, cyclooxygenase-2 (COX-2), determined by ELISA (Enzyme-Linked Immunosorbent Assay) (***P < 0.001 vs. chloroquine group). It downregulates nNOS mRNA expression confirmed by real-time polymerase chain reaction (RT-PCR). CONCLUSION: These findings highlight the therapeutic effects of L-carnitine in alleviating chloroquine-induced pruritus.
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Carnitina , Cloroquina , Óxido Nítrico , Estrés Oxidativo , Prurito , Cloroquina/farmacología , Cloroquina/uso terapéutico , Prurito/tratamiento farmacológico , Prurito/inducido químicamente , Prurito/metabolismo , Óxido Nítrico/metabolismo , Carnitina/farmacología , Carnitina/uso terapéutico , Animales , Estrés Oxidativo/efectos de los fármacos , Masculino , Antipruriginosos/uso terapéutico , Antipruriginosos/farmacología , Transducción de Señal/efectos de los fármacos , Ratones , Ciclooxigenasa 2/metabolismo , Ciclooxigenasa 2/genética , Citocinas/metabolismoRESUMEN
Atopic dermatitis (AD) is extremely common in the pediatric population, and most children with AD will first present to their primary care provider (PCP). The PCP can recognize AD by its clinical features, including itch, a chronic relapsing course, and the characteristic eruption. The cornerstone of AD therapy is dry skin care, typically a short daily bath/shower followed by an emollient applied to all skin. Most children with AD will also require topical medications, such as topical corticosteroids and/or topical nonsteroidal therapies. For children with more severe disease, systemic agents, including several novel therapies, may be required. In managing AD, the clinician must monitor for side effects of medications as well as complications of the AD itself, the most common of which is secondary infection. An understanding of the pathogenesis, treatments, and complications of AD is essential for the PCP, as untreated (or undertreated) AD has a significant impact on the quality of life of affected children and their caregivers. [Pediatr Ann. 2024;53(4):e121-e128.].
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Dermatitis Atópica , Fármacos Dermatológicos , Niño , Humanos , Dermatitis Atópica/diagnóstico , Dermatitis Atópica/etiología , Dermatitis Atópica/terapia , Calidad de Vida , Fármacos Dermatológicos/efectos adversos , Piel/patología , Prurito/inducido químicamente , Prurito/complicacionesRESUMEN
PD-1/PD-L1 inhibitors have been demonstrated to induce itch in both humans and experimental animals. However, whether the PD-1/PD-L1 pathway is involved in the regulation of chronic psoriatic itch remains unclear. This study aimed to investigate the role of the PD-1/PD-L1 pathway in imiquimod-induced chronic psoriatic itch. The intradermal injection of PD-L1 in the nape of neck significantly alleviated chronic psoriatic itch in imiquimod-treated skin. Additionally, we observed that spontaneous scratching behavior induced by imiquimod disappeared on day 21. Still, intradermal injection of PD-1/PD-L1 inhibitors could induce more spontaneous scratching for over a month, indicating that imiquimod-treated skin remained in an itch sensitization state after the spontaneous scratching behavior disappeared. During this period, there was a significant increase in PD-1 receptor expression in both the imiquimod-treated skin and the spinal dorsal horn in mice, accompanied by significant activation of microglia in the spinal dorsal horn. These findings suggest the potential involvement of the peripheral and central PD-1/PD-L1 pathways in regulating chronic itch and itch sensitization induced by imiquimod.
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Antígeno B7-H1 , Imiquimod , Receptor de Muerte Celular Programada 1 , Prurito , Psoriasis , Animales , Imiquimod/farmacología , Imiquimod/efectos adversos , Prurito/inducido químicamente , Prurito/metabolismo , Psoriasis/inducido químicamente , Psoriasis/complicaciones , Psoriasis/metabolismo , Receptor de Muerte Celular Programada 1/metabolismo , Antígeno B7-H1/metabolismo , Masculino , Ratones , Transducción de Señal/efectos de los fármacos , Piel/metabolismo , Piel/patología , Ratones Endogámicos C57BL , Enfermedad CrónicaRESUMEN
PURPOSE: Immune-related cutaneous adverse events (ircAE) occur in ≥50% of patients treated with checkpoint inhibitors, but the underlying mechanisms for ircAEs are poorly understood. EXPERIMENTAL DESIGN: Phenotyping/biomarker analyses were conducted in 200 patients on checkpoint inhibitors [139 with ircAEs and 61 without (control group)] to characterize their clinical presentation and immunologic endotypes. Cytokines were evaluated in skin biopsies, skin tape strip extracts, and plasma using real-time PCR and Meso Scale Discovery multiplex cytokine assays. RESULTS: Eight ircAE phenotypes were identified: pruritus (26%), maculopapular rash (MPR; 21%), eczema (19%), lichenoid (11%), urticaria (8%), psoriasiform (6%), vitiligo (5%), and bullous dermatitis (4%). All phenotypes showed skin lymphocyte and eosinophil infiltrates. Skin biopsy PCR revealed the highest increase in IFNγ mRNA in patients with lichenoid (P < 0.0001) and psoriasiform dermatitis (P < 0.01) as compared with patients without ircAEs, whereas the highest IL13 mRNA levels were detected in patients with eczema (P < 0.0001, compared with control). IL17A mRNA was selectively increased in psoriasiform (P < 0.001), lichenoid (P < 0.0001), bullous dermatitis (P < 0.05), and MPR (P < 0.001) compared with control. Distinct cytokine profiles were confirmed in skin tape strip and plasma. Analysis determined increased skin/plasma IL4 cytokine in pruritus, skin IL13 in eczema, plasma IL5 and IL31 in eczema and urticaria, and mixed-cytokine pathways in MPR. Broad inhibition via corticosteroids or type 2 cytokine-targeted inhibition resulted in clinical benefit in these ircAEs. In contrast, significant skin upregulation of type 1/type 17 pathways was found in psoriasiform, lichenoid, bullous dermatitis, and type 1 activation in vitiligo. CONCLUSIONS: Distinct immunologic ircAE endotypes suggest actionable targets for precision medicine-based interventions.
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Citocinas , Inhibidores de Puntos de Control Inmunológico , Humanos , Masculino , Femenino , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Persona de Mediana Edad , Anciano , Citocinas/metabolismo , Piel/patología , Piel/inmunología , Piel/metabolismo , Piel/efectos de los fármacos , Adulto , Erupciones por Medicamentos/etiología , Erupciones por Medicamentos/patología , Erupciones por Medicamentos/inmunología , Prurito/inmunología , Prurito/inducido químicamente , Prurito/patología , Prurito/etiología , Prurito/genética , Neoplasias/tratamiento farmacológico , Neoplasias/inmunología , Neoplasias/patología , Enfermedades de la Piel/inducido químicamente , Enfermedades de la Piel/inmunología , Enfermedades de la Piel/patología , Enfermedades de la Piel/etiología , Exantema/inducido químicamente , Exantema/patología , Anciano de 80 o más Años , Psoriasis/tratamiento farmacológico , Psoriasis/inmunología , Psoriasis/patología , Psoriasis/genética , Eccema/patología , Eccema/tratamiento farmacológicoAsunto(s)
Dermatitis Herpetiforme , Nivolumab , Humanos , Nivolumab/efectos adversos , Dermatitis Herpetiforme/inducido químicamente , Masculino , Antineoplásicos Inmunológicos/efectos adversos , Erupciones por Medicamentos/etiología , Erupciones por Medicamentos/patología , Femenino , Prurito/inducido químicamenteRESUMEN
Allergic contact dermatitis (ACD) is a common skin disease featured with skin inflammation and a mixed itch/pain sensation. The itch/pain causes the desire to scratch, affecting both physical and psychological aspects of patients. Nevertheless, the mechanisms underlying itch/pain sensation of ACD still remain elusive. Here, we found that oxidative stress and oxidation-related injury were remarkably increased in the inflamed skin of a mouse model of ACD. Reducing oxidative stress significantly attenuated itch/pain-related scratching, allokonesis and skin inflammation. RNA-Sequencing reveals oxidative stress contributes to a series of skin biological processes, including inflammation and immune response. Attenuating oxidative stress reduces overproduction of IL-1ß and IL-33, two critical cytokines involved in inflammation and pain/itch, in the inflamed skin of model mice. Exogenously injecting H2O2 into the neck skin of naïve mice triggered IL-33 overproduction in skin keratinocytes and induced scratching, which was reduced in mice deficient in IL-33 receptor ST2. ACD model mice showed remarkable neutrophil infiltration in the inflamed skin. Blocking neutrophil infiltration reduced oxidative stress and attenuated scratching and skin inflammation. Therefore, our study reveals a critical contribution of neutrophil-derived oxidative stress to skin inflammation and itch/pain-related scratching of ACD model mice via mechanisms involving the triggering of IL-33 overproduction in skin keratinocytes. Targeting skin oxidative stress may represent an effective therapy for ameliorating ACD.
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Dermatitis Alérgica por Contacto , Interleucina-33 , Humanos , Animales , Ratones , Interleucina-33/genética , Citocinas , Peróxido de Hidrógeno/farmacología , Neutrófilos , Piel , Dermatitis Alérgica por Contacto/psicología , Prurito/inducido químicamente , Modelos Animales de Enfermedad , Inflamación , DolorRESUMEN
Itch is a somatosensory sensation to remove potential harmful stimulation with a scratching desire, which could be divided into mechanical and chemical itch according to diverse stimuli, such as wool fiber and insect biting. It has been reported that neuropeptide Y (NPY) neurons, a population of spinal inhibitory interneurons, could gate the transmission of mechanical itch, with no effect on chemical itch. In our study, we verified that chemogenetic activation of NPY neurons could inhibit the mechanical itch as well as the chemical itch, which also attenuated the alloknesis phenomenon in the chronic dry skin model. Afterwards, intrathecal administration of NPY1R agonist, [Leu31, Pro34]-NPY (LP-NPY), showed the similar inhibition effect on mechanical itch, chemical itch and alloknesis as chemo-activation of NPY neurons. Whereas, intrathecal administration of NPY1R antagonist BIBO 3304 enhanced mechanical itch and reversed the alloknesis phenomenon inhibited by LP-NPY treatment. Moreover, selectively knocking down NPY1R by intrathecal injection of Npy1r siRNA enhanced mechanical and chemical itch behavior as well. These results indicate that NPY neurons in spinal cord regulate mechanical and chemical itch, and alloknesis in dry skin model through NPY1 receptors.
Asunto(s)
Neuropéptido Y , Receptores de Neuropéptido Y , Animales , Prurito/inducido químicamente , Transducción de Señal , Médula EspinalRESUMEN
Itch encompasses both sensory and emotional dimensions, with the two dimensions reciprocally exacerbating each other. However, whether a shared neural circuit mechanism governs both dimensions remains elusive. Here, we report that the anterior insular cortex (AIC) is activated by both histamine-dependent and -independent itch stimuli. The activation of AIC elicits aversive emotion and exacerbates pruritogen-induced itch sensation and aversion. Mechanistically, AIC excitatory neurons project to the GABAergic neurons in the dorsal bed nucleus of the stria terminalis (dBNST). Manipulating the activity of the AIC â dBNST pathway affects both itch sensation and itch-induced aversion. Our study discovers the shared neural circuit (AIC â dBNST pathway) underlying the itch sensation and aversion, highlights the critical role of the AIC as a central hub for the itch processing, and provides a framework to understand the neural mechanisms underlying the sensation and emotion interaction.
Asunto(s)
Corteza Insular , Sensación , Humanos , Sensación/fisiología , Neuronas GABAérgicas/metabolismo , Histamina/efectos adversos , Histamina/metabolismo , Prurito/inducido químicamenteRESUMEN
Glycinergic neurons regulate nociceptive and pruriceptive signaling in the spinal cord, but the identity and role of the glycine-regulated neurons are not fully known. Herein, we have characterized spinal glycine receptor alpha 3 (Glra3) subunit-expressing neurons in Glra3-Cre female and male mice. Glra3-Cre(+) neurons express Glra3, are located mainly in laminae III-VI, and respond to glycine. Chemogenetic activation of spinal Glra3-Cre(+) neurons induced biting/licking, stomping, and guarding behaviors, indicative of both a nociceptive and pruriceptive role for this population. Chemogenetic inhibition did not affect mechanical or thermal responses but reduced behaviors evoked by compound 48/80 and chloroquine, revealing a pruriceptive role for these neurons. Spinal cells activated by compound 48/80 or chloroquine express Glra3, further supporting the phenotype. Retrograde tracing revealed that spinal Glra3-Cre(+) neurons receive input from afferents associated with pain and itch, and dorsal root stimulation validated the monosynaptic input. In conclusion, these results show that spinal Glra3(+) neurons contribute to acute communication of compound 48/80- and chloroquine-induced itch in hairy skin.
Asunto(s)
Prurito , Receptores de Glicina , Médula Espinal , Animales , Prurito/inducido químicamente , Prurito/metabolismo , Ratones , Receptores de Glicina/metabolismo , Masculino , Femenino , Médula Espinal/metabolismo , Médula Espinal/efectos de los fármacos , Cloroquina/farmacología , Ratones Transgénicos , Piel/inervación , Ratones Endogámicos C57BL , p-Metoxi-N-metilfenetilamina/farmacología , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Neuronas/fisiologíaRESUMEN
Psychological stress and intestinal leakage are key factors in atopic dermatitis (AD) recurrence and exacerbation. Here, we demonstrate the mechanism underlying bacterial translocation across intestinal epithelial barrier damaged due to stress and further aggravation of trimellitic anhydride (TMA)-induced itch, which remain unclear, in AD mice. Immobilization (IMO) stress exacerbated scratching bouts and colon histological damage, and increased serum corticosterone and lipopolysaccharide (LPS). Orally administered fluorescein isothiocyanate (FITC)-dextran and surgically injected (into the colon) Cy5.5-conjugated LPS were detected in the serum and skin after IMO stress, respectively. The relative abundance of aerobic or facultative anaerobic bacteria was increased in the colon mucus layer, and Lactobacillus murinus, E. coli, Staphylococcus nepalensis, and several strains of Bacillus sp. were isolated from the spleens and mesenteric lymph nodes. Oral antibiotics or intestinal permeability blockers, such as lubiprostone (Lu), 2,4,6-triaminopyrimidine (TAP) and ML-7, inhibited IMO stress-associated itch; however, it was reinduced through intradermal or i.p. injection of LPS without IMO stress. I.p. injection of TAK-242 (resatorvid), a TLR4 inhibitor, abrogated IMO stress-associated itch, which was also confirmed in TLR4-KO mice. IMO stress alone did not cause itch in naïve mice. IMO stress-induced itch aggravation in TMA-treated AD mice might be attributed to the translocation of gut-derived bacterial cells and LPS, which activates peripheral TLR4 signaling.