RESUMO
Immune checkpoint inhibitor therapies act through blockade of inhibitory molecules involved in the regulation of T cells, thus releasing tumor specific T cells to destroy their tumor targets. However, immune checkpoint inhibitors (ICI) can also lead to a breach in self-tolerance resulting in immune-related adverse events (irAEs) that include tissue-specific autoimmunity. This review addresses the question of whether the mechanisms that drive ICI-induced irAEs are shared or distinct with those driving spontaneous autoimmunity, focusing on ICI-induced diabetes, ICI-induced arthritis, and ICI-induced thyroiditis due to the wealth of knowledge about the development of autoimmunity in type 1 diabetes, rheumatoid arthritis, and Hashimoto's thyroiditis. It reviews current knowledge about role of genetics and autoantibodies in the development of ICI-induced irAEs and presents new studies utilizing single-cell omics approaches to identify T-cell signatures associated with ICI-induced irAEs. Collectively, these studies indicate that there are similarities and differences between ICI-induced irAEs and autoimmune disease and that studying them in parallel will provide important insight into the mechanisms critical for maintaining immune tolerance.
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Autoimunidade , Neoplasias , Humanos , Imunoterapia/métodos , Autoanticorpos , Linfócitos TRESUMO
OBJECTIVE: To identify genetic variants associated with the severity of postburn hypertrophic scarring (HTS) using a genome-wide approach. BACKGROUND: Risk of severe postburn HTS is known to depend on race, but the genetic determinants of HTS are unknown. METHODS: We conducted a genome-wide association study (GWAS) in a prospective cohort of adults admitted with deep-partial-thickness burns from 2007 through 2014. Scar severity was assessed over time using the Vancouver Scar Scale (VSS), and DNA was genotyped with a >500,000-marker array. We performed association testing of single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) >0.01 using linear regression of VSS height score on genotype adjusted for patient and injury characteristics as well as population genetic structure. Array-wide significance was based on Bonferroni correction for multiple testing. RESULTS: Of 538 patients (median age 40 years, median burn size 6.0% of body surface area), 71% were men and 76% were White. The mean VSS height score was 1.2 (range: 0-3). Of 289,639 SNPs tested, a variant in the CUB and Sushi multiple domains 1 (CSMD1) gene (rs11136645; MAFâ=â0.49), was significantly associated with decreased scar height (regression coefficientâ=â-0.23, Pâ=â7.9â×â10). CONCLUSIONS: In the first published GWAS of HTS, we report that a common intronic variant in the CSMD1 gene is associated with reduced severity of postburn HTS. If this association is confirmed in an independent cohort, investigating the potential role of CSMD1 in wound healing may elucidate HTS pathophysiology.
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Queimaduras/complicações , Cicatriz Hipertrófica/genética , Estudo de Associação Genômica Ampla , Proteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Queimaduras/genética , Cicatriz Hipertrófica/etiologia , Feminino , Seguimentos , Frequência do Gene , Marcadores Genéticos , Técnicas de Genotipagem , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Índice de Gravidade de Doença , Proteínas Supressoras de Tumor , Adulto JovemRESUMO
While cellular metabolism is known to regulate a number of key biological processes such as cell growth and proliferation, its role in wound healing is unknown. We hypothesized that cutaneous injury would induce significant metabolic changes and that the impaired wound healing seen in diabetes would be associated with a dysfunctional metabolic response to injury. We used a targeted metabolomics approach to characterize the metabolic profile of uninjured skin and full-thickness wounds at day 7 postinjury in nondiabetic (db/-) and diabetic (db/db) mice. By liquid chromatography mass spectrometry, we identified 129 metabolites among all tissue samples. Principal component analysis demonstrated that uninjured skin and wounds have distinct metabolic profiles and that diabetes alters the metabolic profile of both uninjured skin and wounds. Examining individual metabolites, we identified 62 with a significantly altered response to injury in the diabetic mice, with many of these, including glycine, kynurenate, and OH-phenylpyruvate, implicated in wound healing for the first time. Thus, we report the first comprehensive analysis of wound metabolic profiles, and our results highlight the potential for metabolomics to identify novel biomarkers and therapeutic targets for improved wound healing outcomes.
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Diabetes Mellitus Experimental/patologia , Metabolômica , Pele/patologia , Cicatrização , Animais , Proliferação de Células , Cromatografia Líquida , Feminino , Metabolômica/métodos , Camundongos , Terapia de Alvo Molecular , Neovascularização FisiológicaRESUMO
Exhausted CD8 T cells (TEX) are associated with worse outcome in cancer yet better outcome in autoimmunity. Building on our past findings of increased TIGIT+KLRG1+ TEX with teplizumab therapy in type 1 diabetes (T1D), in the absence of treatment we found that the frequency of TIGIT+KLRG1+ TEX is stable within an individual but differs across individuals in both T1D and healthy control (HC) cohorts. This TIGIT+KLRG1+ CD8 TEX population shares an exhaustion-associated EOMES gene signature in HC, T1D, rheumatoid arthritis (RA), and cancer subjects, expresses multiple inhibitory receptors, and is hyporesponsive in vitro, together suggesting co-expression of TIGIT and KLRG1 may broadly define human peripheral exhausted cells. In HC and RA subjects, lower levels of EOMES transcriptional modules and frequency of TIGIT+KLRG1+ TEX were associated with RA HLA risk alleles (DR0401, 0404, 0405, 0408, 1001) even when considering disease status and cytomegalovirus (CMV) seropositivity. Moreover, the frequency of TIGIT+KLRG1+ TEX was significantly increased in RA HLA risk but not non-risk subjects treated with abatacept (CTLA4Ig). The DR4 association and selective modulation with abatacept suggests that therapeutic modulation of TEX may be more effective in DR4 subjects and TEX may be indirectly influenced by cellular interactions that are blocked by abatacept.
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Abatacepte , Alelos , Artrite Reumatoide , Linfócitos T CD8-Positivos , Receptores Imunológicos , Humanos , Abatacepte/uso terapêutico , Abatacepte/farmacologia , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/imunologia , Artrite Reumatoide/genética , Masculino , Feminino , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/efeitos dos fármacos , Adulto , Lectinas Tipo C/genética , Lectinas Tipo C/metabolismo , Antígenos HLA/genética , Antígenos HLA/imunologia , Pessoa de Meia-Idade , Antirreumáticos/uso terapêutico , Predisposição Genética para Doença , Exaustão das Células TRESUMO
Growing evidence indicates that nerves and capillaries interact paracrinely in uninjured skin and cutaneous wounds. Although mature neurons are the predominant neural cell in the skin, neural progenitor cells have also been detected in uninjured adult skin. The aim of this study was to characterize differential paracrine effects of neural progenitor cells and mature sensory neurons on dermal microvascular endothelial cells. Our results suggest that neural progenitor cells and mature sensory neurons have unique secretory profiles and distinct effects on dermal microvascular endothelial cell proliferation, migration, and nitric oxide production. Neural progenitor cells and dorsal root ganglion neurons secrete different proteins related to angiogenesis. Specific to neural progenitor cells were dipeptidyl peptidase-4, IGFBP-2, pentraxin-3, serpin f1, TIMP-1, TIMP-4 and VEGF. In contrast, endostatin, FGF-1, MCP-1 and thrombospondin-2 were specific to dorsal root ganglion neurons. Microvascular endothelial cell proliferation was inhibited by dorsal root ganglion neurons but unaffected by neural progenitor cells. In contrast, microvascular endothelial cell migration in a scratch wound assay was inhibited by neural progenitor cells and unaffected by dorsal root ganglion neurons. In addition, nitric oxide production by microvascular endothelial cells was increased by dorsal root ganglion neurons but unaffected by neural progenitor cells.
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Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Gânglios Espinais/metabolismo , Microvasos/metabolismo , Células-Tronco Neurais/metabolismo , Células Receptoras Sensoriais/metabolismo , Biomarcadores/metabolismo , Comunicação Celular/fisiologia , Diferenciação Celular , Movimento Celular , Proliferação de Células , Técnicas de Cocultura , Cultura em Câmaras de Difusão , Células Endoteliais/citologia , Endotélio Vascular/citologia , Gânglios Espinais/citologia , Humanos , Microvasos/citologia , Células-Tronco Neurais/citologia , Óxido Nítrico/biossíntese , Especificidade de Órgãos , Células Receptoras Sensoriais/citologiaRESUMO
Mesenchymal stem cells (MSC) represent emerging cell-based therapies for diabetes and associated complications. Ongoing clinical trials are using exogenous MSC to treat type 1 and 2 diabetes, cardiovascular disease and non-healing wounds due to diabetes. The majority of these trials are aimed at exploiting the ability of these multipotent mesenchymal stromal cells to release soluble mediators that reduce inflammation and promote both angiogenesis and cell survival at sites of tissue damage. Growing evidence suggests that MSC secretion of soluble factors is dependent on tissue microenvironment. Despite the contribution of fatty acids to the metabolic environment of type 2 diabetes, almost nothing is known about their effects on MSC secretion of growth factors and cytokines. In this study, human bone marrow-derived MSC were exposed to linoleic acid, an omega-6 polyunsaturated fatty acid, or oleic acid, a monounsaturated fatty acid, for seven days in the presence of 5.38 mM glucose. Outcomes measured included MSC proliferation, gene expression, protein secretion and chemotaxis. Linoleic and oleic acids inhibited MSC proliferation and altered MSC expression and secretion of known mediators of angiogenesis. Both unsaturated fatty acids induced MSC to increase secretion of interleukin-6, VEGF and nitric oxide. In addition, linoleic acid but not oleic acid induced MSC to increase production of interleukin-8. Collectively these data suggest that exposure to fatty acids may have functional consequences for MSC therapy. Fatty acids may affect MSC engraftment to injured tissue and MSC secretion of cytokines and growth factors that regulate local cellular responses to injury.
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Proteínas Angiogênicas/metabolismo , Medula Óssea/metabolismo , Ácido Linoleico/farmacologia , Células-Tronco Mesenquimais/metabolismo , Ácido Oleico/farmacologia , Cicatrização , Proteínas Angiogênicas/genética , Medula Óssea/efeitos dos fármacos , Contagem de Células , Proliferação de Células/efeitos dos fármacos , Terapia Baseada em Transplante de Células e Tecidos/métodos , Quimiotaxia/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Glucose/farmacologia , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Óxido Nítrico/metabolismoRESUMO
Genetic variants associated with susceptibility to autoimmune disease have provided important insight into the mechanisms responsible for the loss of immune tolerance and the subsequent development of autoantibodies, tissue damage, and onset of clinical disease. Here, we review how genetic variants shared across multiple autoimmune diseases have contributed to our understanding of global tolerance failure, focusing on variants in the human leukocyte antigen region, PTPN2 and PTPN22, and their role in antigen presentation and T and B cell homeostasis. Variants unique to a specific autoimmune disease such as those in PADI2 and PADI4 that are associated with rheumatoid arthritis are also discussed, addressing their role in disease-specific immunopathology. Current research continues to focus on determining the functional consequences of autoimmune disease-associated variants but has recently expanded to variants in the non-coding regions of the genome using novel approaches to investigate the impact of these variants on mechanisms regulating gene expression. Lastly, studying genetic risk variants in the setting of autoimmunity has clinical implications, helping predict who will develop autoimmune disease and also identifying potential therapeutic targets.
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Artrite Reumatoide , Doenças Autoimunes , Artrite Reumatoide/genética , Autoanticorpos , Doenças Autoimunes/genética , Autoimunidade/genética , Humanos , Tolerância Imunológica/genética , Proteína Tirosina Fosfatase não Receptora Tipo 22/genéticaRESUMO
Elevated levels and enhanced sensing of the pro-inflammatory cytokine interleukin-6 (IL-6) are key features of many autoimmune and inflammatory diseases. To better understand how IL-6 signaling may influence human T cell fate, we investigated the relationships between levels of components of the IL-6R complex, pSTAT responses, and transcriptomic and translational changes in CD4+ and CD8+ T cell subsets from healthy individuals after exposure to IL-6. Our findings highlight the striking heterogeneity in mbIL-6R and gp130 expression and IL-6-driven pSTAT1/3 responses across T cell subsets. Increased mbIL-6R expression correlated with enhanced signaling via pSTAT1 with less impact on pSTAT3, most strikingly in CD4+ naïve T cells. Additionally, IL-6 rapidly induced expression of transcription factors and surface receptors expressed by T follicular helper cells and altered expression of markers of apoptosis. Importantly, many of the features associated with the level of mbIL-6R expression on T cells were recapitulated both in the setting of tocilizumab therapy and when comparing donor CD4+ T cells harboring the genetic variant, IL6R Asp358Ala (rs2228145), known to alter mbIL-6R expression on T cells. Collectively, these findings should be taken into account as we consider the role of IL-6 in disease pathogenesis and translating IL-6 biology into effective therapies for T cell-mediated autoimmune disease.
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Interleucina-6 , Fator de Transcrição STAT1 , Transdução de Sinais , Linfócitos T , Apoptose , Citocinas , Humanos , Doenças do Sistema Imunitário/etiologia , Doenças do Sistema Imunitário/patologia , Interleucina-6/metabolismo , Interleucina-6/farmacologia , Fator de Transcrição STAT1/metabolismo , Linfócitos T/metabolismo , Linfócitos T/patologiaRESUMO
Therapeutics that inhibit IL-6 at different points in its signaling pathway are in clinical use, yet whether the immunological effects of these interventions differ based on their molecular target is unknown. We performed short-term interventions in individuals with type 1 diabetes using anti-IL-6 (siltuximab) or anti-IL-6 receptor (IL-6R; tocilizumab) therapies and investigated the impact of this in vivo blockade on T cell fate and function. Immune outcomes were influenced by the target of the therapeutic intervention (IL-6 versus IL-6R) and by peak drug concentration. Tocilizumab reduced ICOS expression on T follicular helper cell populations and T cell receptor-driven (TCR-driven) STAT3 phosphorylation. Siltuximab reversed resistance to Treg-mediated suppression and increased TCR-driven phosphorylated STAT3 and production of IL-10, IL-21, and IL-27 by T effectors. Together, these findings indicate that the context of IL-6 blockade in vivo drives distinct T cell-intrinsic changes that may influence therapeutic outcomes.
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Citocinas , Receptores de Antígenos de Linfócitos T , Humanos , Citocinas/farmacologia , Transdução de Sinais , FosforilaçãoRESUMO
Cutaneous wounds persist as a health care crisis in spite of increased understanding of the cellular and molecular responses to injury. Contributing significantly to this crisis is the lack of reliable therapies for treatment of wounds that are slow to heal including chronic wounds and deep dermal wounds that develop hypertrophic scars. This article will review the growing evidence demonstrating the promise of multipotent mesenchymal stem/stromal (MSCs) for the treatment of impaired wound healing. MSCs are often referred to as mesenchymal stem cells despite concerns that these cells are not truly stem cells given the lack of evidence demonstrating self-renewal in vivo. Regardless, abundant evidence demonstrates the therapeutic potential of MSCs for repair and regeneration of damaged tissue due to injury or disease. To date, MSC treatment of acute and chronic wounds results in accelerated wound closure with increased epithelialization, granulation tissue formation and angiogenesis. Although there is evidence for MSC differentiation in the wound, most of the therapeutic effects are likely due to MSCs releasing soluble factors that regulate local cellular responses to cutaneous injury. Important challenges need to be overcome before MSCs can be used effectively to treat wounds that are slow to heal.
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Células-Tronco Mesenquimais/fisiologia , Comunicação Parácrina/fisiologia , Transdução de Sinais , Cicatrização/fisiologia , Proliferação de Células , HumanosRESUMO
Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury.
Assuntos
Derme/citologia , Fibroblastos/fisiologia , Regulação da Expressão Gênica/fisiologia , Células-Tronco Mesenquimais/fisiologia , Comunicação Parácrina/fisiologia , Cicatrização/fisiologia , Animais , Antígenos CD/genética , Movimento Celular/efeitos dos fármacos , Movimento Celular/fisiologia , Proliferação de Células , Células Cultivadas , Quimiotaxia/efeitos dos fármacos , Quimiotaxia/fisiologia , Técnicas de Cocultura , Meios de Cultivo Condicionados/farmacologia , Regulação para Baixo/genética , Feminino , Fibroblastos/citologia , Expressão Gênica/genética , Humanos , Cadeias alfa de Integrinas/genética , Molécula 1 de Adesão Intercelular/genética , Metaloproteinase 11 da Matriz/genética , Camundongos , Camundongos Endogâmicos C57BL , Fator de Crescimento Transformador beta1/genética , Regulação para Cima/genética , Molécula 1 de Adesão de Célula Vascular/genética , Cicatrização/efeitos dos fármacosRESUMO
Comprehensive data on early prognostic indicators in patients with mild COVID-19 remains sparse. In this single center case series, we characterized the initial clinical presentation in 180 patients with mild COVID-19 and defined the earliest predictors of subsequent deterioration and need for hospitalization. Three broad patient phenotypes and four symptom clusters were characterized, differentiated by varying risk for adverse outcomes. Among 14 symptoms assessed, subjective shortness of breath (SOB) most strongly associated with adverse outcomes (odds ratio (OR) 21.3, 95% confidence interval (CI): 2.7-166.4; p < 0.0001). In combination, SOB and number of comorbidities were highly predictive of subsequent hospitalization (area under the curve (AUC) 92%). Additionally, initial lymphopenia (OR 21.0, 95% CI: 2.1-210.1; p = 0.002) and male sex (OR 3.5, 95% CI: 0.9-13.0; p = 0.05) were associated with increased risk of poor outcomes. Patients with known comorbidities, especially multiple, and those presenting with subjective SOB or lymphopenia should receive close monitoring and consideration for preemptive treatment, even when presenting with mild symptoms.
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BACKGROUNDDespite a rapidly growing body of literature on coronavirus disease 2019 (COVID-19), our understanding of the immune correlates of disease severity, course, and outcome remains poor.METHODSUsing mass cytometry, we assessed the immune landscape in longitudinal whole-blood specimens from 59 patients presenting with acute COVID-19 and classified based on maximal disease severity. Hospitalized patients negative for SARS-CoV-2 were used as controls.RESULTSWe found that the immune landscape in COVID-19 formed 3 dominant clusters, which correlated with disease severity. Longitudinal analysis identified a pattern of productive innate and adaptive immune responses in individuals who had a moderate disease course, whereas those with severe disease had features suggestive of a protracted and dysregulated immune response. Further, we identified coordinate immune alterations accompanying clinical improvement and decline that were also seen in patients who received IL-6 pathway blockade.CONCLUSIONThe hospitalized COVID-19 negative cohort allowed us to identify immune alterations that were shared between severe COVID-19 and other critically ill patients. Collectively, our findings indicate that selection of immune interventions should be based in part on disease presentation and early disease trajectory due to the profound differences in the immune response in those with mild to moderate disease and those with the most severe disease.FUNDINGBenaroya Family Foundation, the Leonard and Norma Klorfine Foundation, Glenn and Mary Lynn Mounger, and the National Institutes of Health.
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Imunidade Adaptativa , COVID-19/imunologia , Imunidade Inata , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Citometria de Fluxo , Humanos , Masculino , Pessoa de Meia-Idade , Tratamento Farmacológico da COVID-19RESUMO
[This corrects the article DOI: 10.3389/fimmu.2018.01978.].
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Multiple studies of B- and T-cell compartments and their response to stimuli demonstrate alterations in established type 1 diabetes (T1D). Yet it is not known whether these alterations reflect immune mechanisms that initiate islet autoimmunity, promote disease progression, or are secondary to disease. To address these questions, we used samples from the TrialNet Pathway to Prevention study to investigate T-cell responses to interleukin (IL)-2 and regulatory T cell-mediated suppression, the composition of the B-cell compartment, and B-cell responses to B-cell receptor and IL-21 receptor engagement. These studies revealed stage-dependent T- and B-cell functional and immune phenotypes; namely, early features that differentiate autoantibody-positive at-risk first-degree relatives (FDRs) from autoantibody-negative FDRs and persisted through clinical diagnosis; late features that arose at or near T1D diagnosis; and dynamic features that were enhanced early and blunted at later disease stages, indicating evolving responses along the continuum of T1D. We further explored how these specific phenotypes are influenced by therapeutic interventions. Our integrated studies provide unique insights into stable and dynamic stage-specific immune states and define novel immune phenotypes of potential clinical relevance.
Assuntos
Linfócitos B/imunologia , Diabetes Mellitus Tipo 1/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Adolescente , Adulto , Doenças Assintomáticas , Autoanticorpos/imunologia , Subpopulações de Linfócitos B/imunologia , Linfócitos B/efeitos dos fármacos , Criança , Progressão da Doença , Feminino , Humanos , Memória Imunológica/imunologia , Interleucina-2/farmacologia , Masculino , Fenótipo , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Interleucina-21/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Adulto JovemRESUMO
B cells are implicated in rheumatoid arthritis (RA) based on the presence of autoantibodies and the therapeutic response to B cell depletion. IL-21 has a significant role in B cell development and function. Here we assess B cell responses to IL-21 and the mechanisms responsible for altered IL-21R expression in RA. Flow cytometry of PBMC and cultured B cells was used to quantify protein and mRNA levels of IL-21R, IL-21 signaling through pSTAT3, specificity protein 1 (SP1) and to determine cytokine production (IL-6) and maturation status of B cells in RA and healthy control subjects. SP1 binding to the IL21R promoter region in B cells was assessed with ChIP-qPCR. We demonstrate an increase in IL-21R expression in total and memory B cells from RA subjects, which correlated with responsiveness to IL-21 stimulation. Stimulation of naïve RA B cells with IL-21 and CD40L resulted in an increase in differentiation into plasmablasts and an increase in IL-6 production in comparison to healthy controls, which was dose dependent on IL-21 stimulation. IL-21R expression on memory B cells in RA synovial fluid was comparable to peripheral blood making our study pertinent to understanding B cell responses in the joint and site of inflammation. We identified an increase in SP1 protein and mRNA in RA B cells and demonstrate an increase in binding of SP1 to the IL21R promoter region, which suggests a mechanism by which IL-21R expression is enhanced on B cells in RA. Taken together, our results indicate a mechanism by which IL-21 enhances B cell development and function in RA through an SP1 mediated increase in IL-21R expression on B cells.
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Artrite Reumatoide/imunologia , Linfócitos B/imunologia , Regiões Promotoras Genéticas/genética , Receptores de Interleucina-21/genética , Fator de Transcrição Sp1/metabolismo , Adulto , Animais , Células Cultivadas , Estudos de Coortes , Estudos Transversais , Humanos , Memória Imunológica , Interleucinas/metabolismo , Ativação Linfocitária , Camundongos , Pessoa de Meia-Idade , Ligação Proteica , Transdução de SinaisRESUMO
Significance: Mesenchymal stem cells (MSCs) are being administered to cutaneous wounds with the goal of accelerating wound closure and promoting regeneration instead of scar formation. An ongoing challenge for cell-based therapies is achieving effective and optimal targeted delivery and engraftment at the site of injury. Contributing to this challenge is our incomplete understanding of endogenous MSC homing to sites of injury. Recent Advances: Chemokines and their receptors are now recognized as important mediators of stem cell homing. To date, the most studied chemokine-chemokine receptor axis in MSC homing to wounds is CXCL12-CXCR4 but recent work suggests that CCL27-CCR10 and CCL21-CCR7 may also be involved. Critical Issues: Strategies to enhance chemokine-mediated MSC homing to wounds are using a variety of approaches to amplify the chemokine signal at the wound site and/or overexpress specific chemokine receptors on the surface of the MSC. Future Directions: Harnessing chemokine signaling may enhance the therapeutic effects of stem cell therapy by increasing the number of both exogenous and endogenous stem cells recruited to the site of injury. Alternatively, chemokine-based therapies directly targeting endogenous stem cells may circumvent the need for the time-consuming and costly isolation and expansion of autologous stem cells prior to therapeutic administration.
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The genetic determinants of post-burn hypertrophic scarring (HTS) are unknown, and melanocortin 1 receptor (MC1R) loss-of-function leads to fibrogenesis in experimental models. To examine the associations between self-identified race and MC1R single-nucleotide polymorphisms (SNPs) with severity of post-burn HTS, we conducted a prospective cohort study of burned adults admitted to our institution over 7 years. Subjects were evaluated using the Vancouver Scar Scale (VSS), asked to rate their itching, and genotyped for 8 MC1R SNPs. Testing for association with severe HTS (VSS>7) and itch severity (0-10) was based on multivariate regression with adjustment for known risk factors. Of 425 subjects analyzed, 77% identified as White. The prevalence of severe HTS (VSS>7) was 49%, and the mean itch score was 3.9. In multivariate analysis, Asian (prevalence ratio (PR) 1.54; 95% CI: 1.13-2.10), Black/African American (PR 1.86; 95% CI: 1.42-2.45), and Native American (PR 1.87; 95% CI: 1.48-2.35) race were independently associated with severe HTS. MC1R SNP R163Q was also significantly (P<0.001) associated with severe HTS. Asian race (linear regression coefficient 1.32; 95% CI: 0.23-2.40) but not MC1R SNP genotype was associated with increased itch score. We conclude that MC1R genotype may influence post-burn scarring.
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Queimaduras/sangue , Cicatriz Hipertrófica/etnologia , Cicatriz Hipertrófica/genética , Polimorfismo de Nucleotídeo Único , Receptor Tipo 1 de Melanocortina/genética , Adulto , Queimaduras/complicações , Queimaduras/terapia , Cicatriz Hipertrófica/etiologia , Cicatriz Hipertrófica/patologia , Estudos de Coortes , Feminino , Genótipo , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Distribuição de Poisson , Prevalência , Estudos Prospectivos , Medição de Risco , Índice de Gravidade de Doença , Cicatrização/genética , Cicatrização/fisiologiaRESUMO
BACKGROUND: The pathophysiology of hypertrophic scarring is unknown in part because of the lack of a robust animal model. Although the red Duroc pig has emerged as a promising in vivo model, the cellular mechanisms underlying Duroc scarring are unknown, and the size and cost of Duroc pigs are obstacles to their use. Given the central role of the dermal fibroblast in scarring, the authors hypothesized that dermal fibroblasts from the Duroc pig exhibit intrinsic differences in key aspects of the fibroblast response to injury compared with those from the Yorkshire pig, a same-species control that heals normally. METHODS: Duroc and Yorkshire dermal fibroblasts were isolated from uninjured dorsal skin. Actin stress fibers and focal adhesions were visualized by immunocytochemistry and transmission electron microscopy. Cell migration was measured using a scratch wound-closure assay. Contractile function was assessed by collagen gel contraction. Expression of scarring-related genes was determined by quantitative real-time reverse-transcriptase polymerase chain reaction, and transforming growth factor (TGF)-ß1 protein expression was determined by Western blotting. RESULTS: Duroc dermal fibroblasts display increased adhesion-complex formation, impaired migration, enhanced collagen contraction, and profibrotic gene and protein expression profiles compared with Yorkshire fibroblasts at baseline. In addition, Duroc fibroblasts overexpressed TGF-ß1 and were less responsive to exogenous TGF-ß1. CONCLUSIONS: Duroc dermal fibroblasts have inherent myofibroblastic differentiation that may account for the pathologic scarring in these animals. The authors' data further validate the Duroc model and support Duroc fibroblast cell culture as a simple, inexpensive, reproducible, and biologically tractable in vitro model for the study of fibroproliferative scarring.
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Movimento Celular/genética , Cicatriz Hipertrófica/genética , Fibroblastos/citologia , Regulação da Expressão Gênica , Fator de Crescimento Transformador beta1/genética , Animais , Western Blotting , Adesão Celular/genética , Movimento Celular/fisiologia , Proliferação de Células/genética , Células Cultivadas , Cicatriz Hipertrófica/patologia , Modelos Animais de Doenças , Feminino , Fibroblastos/fisiologia , Técnicas In Vitro , Microscopia Eletrônica de Transmissão , Fenótipo , Reação em Cadeia da Polimerase em Tempo Real , Especificidade da Espécie , Sus scrofa , SuínosRESUMO
INTRODUCTION: Abnormal pigmentation following cutaneous injury causes significant patient distress and represents a barrier to recovery. Wound depth and patient characteristics influence scar pigmentation. However, we know little about the pathophysiology leading to hyperpigmentation in healed shallow wounds and hypopigmentation in deep dermal wound scars. We sought to determine whether dermal fibroblast signaling influences melanocyte responses. METHODS AND MATERIALS: Epidermal melanocytes from three Caucasians and three African-Americans were genotyped for single nucleotide polymorphisms (SNPs) across the entire genome. Melanocyte genetic profiles were determined using principal component analysis. We assessed melanocyte phenotype and gene expression in response to dermal fibroblast-conditioned medium and determined potential mesenchymal mediators by proteome profiling the fibroblast-conditioned medium. RESULTS: Six melanocyte samples demonstrated significant variability in phenotype and gene expression at baseline and in response to fibroblast-conditioned medium. Genetic profiling for SNPs in receptors for 13 identified soluble fibroblast-secreted mediators demonstrated considerable heterogeneity, potentially explaining the variable melanocyte responses to fibroblast-conditioned medium. DISCUSSION: Our data suggest that melanocytes respond to dermal fibroblast-derived mediators independent of keratinocytes and raise the possibility that mesenchymal-epidermal interactions influence skin pigmentation during cutaneous scarring.