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1.
Cancer Res ; 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642183

RESUMO

The relationship between cancer and autoimmunity is complex. However, the incidence of solid tumors such as melanoma has increased significantly among patients with previous or newly diagnosed systemic autoimmune disease (AID). At the same time, immune checkpoint blockade (ICB) therapy of cancer induces de novo autoinflammation and exacerbates underlying AID, even without evident anti-tumor responses. Recently, systemic lupus erythematosus (SLE) activity was found to drive myeloid-derived suppressor cell (MDSC) formation in patients, a known barrier to healthy immune surveillance and successful cancer immunotherapy. Crosstalk between MDSCs and macrophages generally drives immune suppressive activity in the tumor microenvironment. However, it remains unclear how peripheral pre-generated MDSC under chronic inflammatory conditions modulates global macrophage immune functions and the impact it could have on existing tumors and underlying lupus nephritis. Here we show that pathogenic expansion of SLE-generated MDSCs by melanoma drives global macrophage polarization and simultaneously impacts the severity of lupus nephritis and tumor progression in SLE-prone mice. Molecular and functional data showed that MDSCs interact with autoimmune macrophages and inhibit cell surface expression of CD40 and the production of IL-27. Moreover, low CD40/IL-27 signaling in tumors correlated with high TAM infiltration and ICB therapy resistance both in murine and human melanoma exhibiting active IFNγ signatures. These results suggest that preventing global macrophage reprogramming induced by MDSC-mediated inhibition of CD40/IL-27 signaling provides a precision melanoma immunotherapy strategy, supporting an original and advantageous approach to treat solid tumors within established autoimmune landscapes.

4.
Oncogene ; 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433909

RESUMO

Hepatocyte growth factor-overexpressing mice that harbor a deletion of the Ink4a/p16 locus (HP mice) form melanomas with low metastatic potential in response to UV irradiation. Here we report that these tumors become highly metastatic following hemizygous deletion of the Nme1 and Nme2 metastasis suppressor genes (HPN mice). Whole-genome sequencing of melanomas from HPN mice revealed a striking increase in lung metastatic activity that is associated with missense mutations in eight signature genes (Arhgap35, Atp8b4, Brca1, Ift172, Kif21b, Nckap5, Pcdha2, and Zfp869). RNA-seq analysis of transcriptomes from HP and HPN primary melanomas identified a 32-gene signature (HPN lung metastasis signature) for which decreased expression is strongly associated with lung metastatic potential. Analysis of transcriptome data from The Cancer Genome Atlas revealed expression profiles of these genes that predict improved survival of patients with cutaneous or uveal melanoma. Silencing of three representative HPN lung metastasis signature genes (ARRDC3, NYNRIN, RND3) in human melanoma cells resulted in increased invasive activity, consistent with roles for these genes as mediators of the metastasis suppressor function of NME1 and NME2. In conclusion, our studies have identified a family of genes that mediate suppression of melanoma lung metastasis, and which may serve as prognostic markers and/or therapeutic targets for clinical management of metastatic melanoma.

5.
Am J Hum Genet ; 108(9): 1611-1630, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34343493

RESUMO

Genome-wide association studies (GWASs) have identified a melanoma-associated locus on chromosome band 7p21.1 with rs117132860 as the lead SNP and a secondary independent signal marked by rs73069846. rs117132860 is also associated with tanning ability and cutaneous squamous cell carcinoma (cSCC). Because ultraviolet radiation (UVR) is a key environmental exposure for all three traits, we investigated the mechanisms by which this locus contributes to melanoma risk, focusing on cellular response to UVR. Fine-mapping of melanoma GWASs identified four independent sets of candidate causal variants. A GWAS region-focused Capture-C study of primary melanocytes identified physical interactions between two causal sets and the promoter of the aryl hydrocarbon receptor (AHR). Subsequent chromatin state annotation, eQTL, and luciferase assays identified rs117132860 as a functional variant and reinforced AHR as a likely causal gene. Because AHR plays critical roles in cellular response to dioxin and UVR, we explored links between this SNP and AHR expression after both 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and ultraviolet B (UVB) exposure. Allele-specific AHR binding to rs117132860-G was enhanced following both, consistent with predicted weakened AHR binding to the risk/poor-tanning rs117132860-A allele, and allele-preferential AHR expression driven from the protective rs117132860-G allele was observed following UVB exposure. Small deletions surrounding rs117132860 introduced via CRISPR abrogates AHR binding, reduces melanocyte cell growth, and prolongs growth arrest following UVB exposure. These data suggest AHR is a melanoma susceptibility gene at the 7p21.1 risk locus and rs117132860 is a functional variant within a UVB-responsive element, leading to allelic AHR expression and altering melanocyte growth phenotypes upon exposure.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Carcinoma de Células Escamosas/genética , Cromossomos Humanos Par 7 , Loci Gênicos , Melanócitos/metabolismo , Melanoma/genética , Receptores de Hidrocarboneto Arílico/genética , Neoplasias Cutâneas/genética , Alelos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Cromatina/química , Cromatina/metabolismo , Regulação da Expressão Gênica , Predisposição Genética para Doença , Genoma Humano , Estudo de Associação Genômica Ampla , Humanos , Melanócitos/efeitos dos fármacos , Melanócitos/patologia , Melanócitos/efeitos da radiação , Melanoma/metabolismo , Melanoma/patologia , Dibenzodioxinas Policloradas/toxicidade , Polimorfismo de Nucleotídeo Único , Cultura Primária de Células , Regiões Promotoras Genéticas , Receptores de Hidrocarboneto Arílico/metabolismo , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Banho de Sol , Raios Ultravioleta/efeitos adversos
6.
Mol Cancer Res ; 19(8): 1422-1436, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33888600

RESUMO

Only a subset of patients responds to immune checkpoint blockade (ICB) in melanoma. A preclinical model recapitulating the clinical activity of ICB would provide a valuable platform for mechanistic studies. We used melanoma tumors arising from an Hgftg;Cdk4R24C/R24C genetically engineered mouse (GEM) model to evaluate the efficacy of an anti-mouse PD-L1 antibody similar to the anti-human PD-L1 antibodies durvalumab and atezolizumab. Consistent with clinical observations for ICB in melanoma, anti-PD-L1 treatment elicited complete and durable response in a subset of melanoma-bearing mice. We also observed tumor growth delay or regression followed by recurrence. For early treatment assessment, we analyzed gene expression profiles, T-cell infiltration, and T-cell receptor (TCR) signatures in regressing tumors compared with tumors exhibiting no response to anti-PD-L1 treatment. We found that CD8+ T-cell tumor infiltration corresponded to response to treatment, and that anti-PD-L1 gene signature response indicated an increase in antigen processing and presentation, cytokine-cytokine receptor interaction, and natural killer cell-mediated cytotoxicity. TCR sequence data suggest that an anti-PD-L1-mediated melanoma regression response requires not only an expansion of the TCR repertoire that is unique to individual mice, but also tumor access to the appropriate TCRs. Thus, this melanoma model recapitulated the variable response to ICB observed in patients and exhibited biomarkers that differentiate between early response and resistance to treatment, providing a valuable platform for prediction of successful immunotherapy. IMPLICATIONS: Our melanoma model recapitulates the variable response to anti-PD-L1 observed in patients and exhibits biomarkers that characterize early antibody response, including expansion of the TCR repertoire.

7.
Clin Cancer Res ; 27(11): 3190-3200, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33568347

RESUMO

PURPOSE: Uveal melanoma is the most common eye cancer in adults. Approximately 50% of patients with uveal melanoma develop metastatic uveal melanoma (mUM) in the liver, even after successful treatment of the primary lesions. mUM is refractory to current chemo- and immune-therapies, and most mUM patients die within a year. Uveal melanoma is characterized by gain-of-function mutations in GNAQ/GNA11, encoding Gαq proteins. We have recently shown that the Gαq-oncogenic signaling circuitry involves a noncanonical pathway distinct from the classical activation of PLCß and MEK-ERK. GNAQ promotes the activation of YAP1, a key oncogenic driver, through focal adhesion kinase (FAK), thereby identifying FAK as a druggable signaling hub downstream from GNAQ. However, targeted therapies often activate compensatory resistance mechanisms leading to cancer relapse and treatment failure. EXPERIMENTAL DESIGN: We performed a kinome-wide CRISPR-Cas9 sgRNA screen to identify synthetic lethal gene interactions that can be exploited therapeutically. Candidate adaptive resistance mechanisms were investigated by cotargeting strategies in uveal melanoma and mUM in vitro and in vivo experimental systems. RESULTS: sgRNAs targeting the PKC and MEK-ERK signaling pathways were significantly depleted after FAK inhibition, with ERK activation representing a predominant resistance mechanism. Pharmacologic inhibition of MEK and FAK showed remarkable synergistic growth-inhibitory effects in uveal melanoma cells and exerted cytotoxic effects, leading to tumor collapse in uveal melanoma xenograft and liver mUM models in vivo. CONCLUSIONS: Coupling the unique genetic landscape of uveal melanoma with the power of unbiased genetic screens, our studies reveal that FAK and MEK-ERK cotargeting may provide a new network-based precision therapeutic strategy for mUM treatment.See related commentary by Harbour, p. 2967.

8.
Cancer Cell ; 39(5): 610-631, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33545064

RESUMO

There is a lack of appropriate melanoma models that can be used to evaluate the efficacy of novel therapeutic modalities. Here, we discuss the current state of the art of melanoma models including genetically engineered mouse, patient-derived xenograft, zebrafish, and ex vivo and in vitro models. We also identify five major challenges that can be addressed using such models, including metastasis and tumor dormancy, drug resistance, the melanoma immune response, and the impact of aging and environmental exposures on melanoma progression and drug resistance. Additionally, we discuss the opportunity for building models for rare subtypes of melanomas, which represent an unmet critical need. Finally, we identify key recommendations for melanoma models that may improve accuracy of preclinical testing and predict efficacy in clinical trials, to help usher in the next generation of melanoma therapies.

9.
Clin Cancer Res ; 27(10): 2678-2697, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33414132

RESUMO

Five years ago, the Melanoma Research Foundation (MRF) conducted an assessment of the challenges and opportunities facing the melanoma research community and patients with melanoma. Since then, remarkable progress has been made on both the basic and clinical research fronts. However, the incidence, recurrence, and death rates for melanoma remain unacceptably high and significant challenges remain. Hence, the MRF Scientific Advisory Council and Breakthrough Consortium, a group that includes clinicians and scientists, reconvened to facilitate intensive discussions on thematic areas essential to melanoma researchers and patients alike, prevention, detection, diagnosis, metastatic dormancy and progression, response and resistance to targeted and immune-based therapy, and the clinical consequences of COVID-19 for patients with melanoma and providers. These extensive discussions helped to crystalize our understanding of the challenges and opportunities facing the broader melanoma community today. In this report, we discuss the progress made since the last MRF assessment, comment on what remains to be overcome, and offer recommendations for the best path forward.


Assuntos
COVID-19/prevenção & controle , Oncologia/métodos , Melanoma/terapia , Guias de Prática Clínica como Assunto , SARS-CoV-2/isolamento & purificação , Neoplasias Cutâneas/terapia , Pesquisa Biomédica/métodos , Pesquisa Biomédica/tendências , COVID-19/epidemiologia , COVID-19/virologia , Humanos , Oncologia/organização & administração , Oncologia/tendências , Melanoma/diagnóstico , SARS-CoV-2/fisiologia , Neoplasias Cutâneas/diagnóstico
11.
Br J Cancer ; 124(1): 161-165, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33024267

RESUMO

NME1 is a metastasis-suppressor gene (MSG), capable of suppressing metastatic activity in cell lines of melanoma, breast carcinoma and other cancer origins without affecting their growth in culture or as primary tumours. Herein, we selectively ablated the tandemly arranged Nme1 and Nme2 genes to assess their individual impacts on metastatic activity in a mouse model (HGF:p16-/-) of ultraviolet radiation (UVR)-induced melanoma. Metastatic activity was strongly enhanced in both genders of Nme1- and Nme2-null mice, with stronger activity in females across all genotypes. The study ascribes MSG activity to Nme2 for the first time in an in vivo model of spontaneous cancer, as well as a novel metastasis-suppressor function to Nme1 in the specific context of UVR-induced melanoma.


Assuntos
Genes Supressores de Tumor , Melanoma/genética , Melanoma/patologia , Nucleosídeo NM23 Difosfato Quinases/genética , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Raios Ultravioleta/efeitos adversos
12.
Bioinformatics ; 36(Suppl_1): i169-i176, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32657358

RESUMO

MOTIVATION: Recent advances in single-cell sequencing (SCS) offer an unprecedented insight into tumor emergence and evolution. Principled approaches to tumor phylogeny reconstruction via SCS data are typically based on general computational methods for solving an integer linear program, or a constraint satisfaction program, which, although guaranteeing convergence to the most likely solution, are very slow. Others based on Monte Carlo Markov Chain or alternative heuristics not only offer no such guarantee, but also are not faster in practice. As a result, novel methods that can scale up to handle the size and noise characteristics of emerging SCS data are highly desirable to fully utilize this technology. RESULTS: We introduce PhISCS-BnB (phylogeny inference using SCS via branch and bound), a branch and bound algorithm to compute the most likely perfect phylogeny on an input genotype matrix extracted from an SCS dataset. PhISCS-BnB not only offers an optimality guarantee, but is also 10-100 times faster than the best available methods on simulated tumor SCS data. We also applied PhISCS-BnB on a recently published large melanoma dataset derived from the sublineages of a cell line involving 20 clones with 2367 mutations, which returned the optimal tumor phylogeny in <4 h. The resulting phylogeny agrees with and extends the published results by providing a more detailed picture on the clonal evolution of the tumor. AVAILABILITY AND IMPLEMENTATION: https://github.com/algo-cancer/PhISCS-BnB. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Algoritmos , Neoplasias , Humanos , Cadeias de Markov , Neoplasias/genética , Filogenia , Análise de Sequência , Software
13.
Nat Med ; 26(5): 781-791, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32284588

RESUMO

Although immunotherapy has revolutionized cancer treatment, only a subset of patients demonstrate durable clinical benefit. Definitive predictive biomarkers and targets to overcome resistance remain unidentified, underscoring the urgency to develop reliable immunocompetent models for mechanistic assessment. Here we characterize a panel of syngeneic mouse models, representing a variety of molecular and phenotypic subtypes of human melanomas and exhibiting their diverse range of responses to immune checkpoint blockade (ICB). Comparative analysis of genomic, transcriptomic and tumor-infiltrating immune cell profiles demonstrated alignment with clinical observations and validated the correlation of T cell dysfunction and exclusion programs with resistance. Notably, genome-wide expression analysis uncovered a melanocytic plasticity signature predictive of patient outcome in response to ICB, suggesting that the multipotency and differentiation status of melanoma can determine ICB benefit. Our comparative preclinical platform recapitulates melanoma clinical behavior and can be employed to identify mechanisms and treatment strategies to improve patient care.


Assuntos
Ensaios de Seleção de Medicamentos Antitumorais , Imunoterapia , Melanoma/patologia , Melanoma/terapia , Animais , Antineoplásicos Imunológicos/uso terapêutico , Antígeno CTLA-4/imunologia , Células Cultivadas , Modelos Animais de Doenças , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Heterogeneidade Genética , Humanos , Imunoterapia/efeitos adversos , Imunoterapia/métodos , Ipilimumab/uso terapêutico , Melanoma/diagnóstico , Melanoma/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Prognóstico , Receptor de Morte Celular Programada 1/imunologia , RNA-Seq , Resultado do Tratamento , Sequenciamento Completo do Genoma
14.
Cancer Res ; 80(4): 655-656, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-32060226

RESUMO

The study by Bok and colleagues in this issue introduces a new paradigm for generating new mouse models for melanoma research. Genetically engineered mouse models (GEMM) have been crucial for understanding tumor initiation and modeling potential therapies, but are time consuming to create. Bok and colleagues generated and validated high-contribution chimeric GEMM models using common melanoma GEMMs as a starting point and added additional CRISPR, Cre-inducible, and Dox-inducible alleles. This rapid method for generating new models has the potential to revolutionize mouse modeling for melanoma.See related article by Bok et al., p. 912.


Assuntos
Células-Tronco Embrionárias , Melanoma/genética , Animais , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Modelos Animais de Doenças , Camundongos
15.
Nat Commun ; 11(1): 333, 2020 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949145

RESUMO

Cutaneous malignant melanoma is an aggressive cancer of melanocytes with a strong propensity to metastasize. We posit that melanoma cells acquire metastatic capability by adopting an embryonic-like phenotype, and that a lineage approach would uncover metastatic melanoma biology. Using a genetically engineered mouse model to generate a rich melanoblast transcriptome dataset, we identify melanoblast-specific genes whose expression contribute to metastatic competence and derive a 43-gene signature that predicts patient survival. We identify a melanoblast gene, KDELR3, whose loss impairs experimental metastasis. In contrast, KDELR1 deficiency enhances metastasis, providing the first example of different disease etiologies within the KDELR-family of retrograde transporters. We show that KDELR3 regulates the metastasis suppressor, KAI1, and report an interaction with the E3 ubiquitin-protein ligase gp78, a regulator of KAI1 degradation. Our work demonstrates that the melanoblast transcriptome can be mined to uncover targetable pathways for melanoma therapy.


Assuntos
Perfilação da Expressão Gênica , Melanoma/genética , Melanoma/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Transcriptoma , Animais , Linhagem Celular Tumoral , Retículo Endoplasmático , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Proteína Kangai-1/genética , Proteína Kangai-1/metabolismo , Pulmão/patologia , Melanócitos/metabolismo , Melanoma/patologia , Camundongos , Camundongos Endogâmicos C57BL , Metástase Neoplásica/genética , Segunda Neoplasia Primária/patologia , Fenótipo , Receptores de Peptídeos/genética , Receptores de Peptídeos/metabolismo , Neoplasias Cutâneas/patologia , Ubiquitina-Proteína Ligases/metabolismo
16.
Cell ; 179(1): 219-235.e21, 2019 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-31522890

RESUMO

Although clonal neo-antigen burden is associated with improved response to immune therapy, the functional basis for this remains unclear. Here we study this question in a novel controlled mouse melanoma model that enables us to explore the effects of intra-tumor heterogeneity (ITH) on tumor aggressiveness and immunity independent of tumor mutational burden. Induction of UVB-derived mutations yields highly aggressive tumors with decreased anti-tumor activity. However, single-cell-derived tumors with reduced ITH are swiftly rejected. Their rejection is accompanied by increased T cell reactivity and a less suppressive microenvironment. Using phylogenetic analyses and mixing experiments of single-cell clones, we dissect two characteristics of ITH: the number of clones forming the tumor and their clonal diversity. Our analysis of melanoma patient tumor data recapitulates our results in terms of overall survival and response to immune checkpoint therapy. These findings highlight the importance of clonal mutations in robust immune surveillance and the need to quantify patient ITH to determine the response to checkpoint blockade.


Assuntos
Heterogeneidade Genética/efeitos da radiação , Melanoma/genética , Melanoma/imunologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia , Raios Ultravioleta/efeitos adversos , Animais , Carcinogênese/genética , Linhagem Celular Tumoral , Estudos de Coortes , Modelos Animais de Doenças , Feminino , Humanos , Linfócitos do Interstício Tumoral , Melanoma/mortalidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Mutação/efeitos da radiação , Filogenia , Neoplasias Cutâneas/mortalidade , Taxa de Sobrevida , Linfócitos T/imunologia , Microambiente Tumoral/imunologia , Microambiente Tumoral/efeitos da radiação
17.
Nat Commun ; 10(1): 1492, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-30940817

RESUMO

Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5-/- and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5-/- mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5-/- mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth.


Assuntos
Proliferação de Células , Microbioma Gastrointestinal , Melanoma/imunologia , Melanoma/microbiologia , Proteínas de Membrana/deficiência , Ubiquitina-Proteína Ligases/deficiência , Animais , Peptídeos Catiônicos Antimicrobianos/imunologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Humanos , Intestinos/imunologia , Intestinos/microbiologia , Melanoma/enzimologia , Melanoma/fisiopatologia , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/imunologia , Resposta a Proteínas não Dobradas
18.
Cancer Discov ; 9(1): 19-21, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30626604

RESUMO

In this issue, Weeraratna and colleagues demonstrate that observed differences in melanoma aggressiveness in younger versus older patients can be explained not just by cell-intrinsic alterations over time, but by age-dependent changes in fibroblasts and the extracellular matrix they help create. Their findings identify novel cellular targets for melanoma therapy, as well as candidate prognostic biomarkers to better inform clinical decisions for patients with melanoma.See related article by Kaur et al., p. 64.See related article by Ecker et al., p. 82.


Assuntos
Vasos Linfáticos , Melanoma , Fibroblastos , Humanos , Permeabilidade , Microambiente Tumoral
19.
Invest Ophthalmol Vis Sci ; 59(15): 6067-6073, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30590377

RESUMO

Purpose: Complete deficiency of microphthalmia transcription factor (MITF) in Mitfmi-vga9/mi-vga9 mice is associated with microphthalmia, retinal dysplasia, and albinism. We investigated the ability of dopachrome tautomerase (DCT) promoter-mediated inducible ectopic expression of Mitf-M to rescue these phenotypic abnormalities. Methods: A new mouse line was created with doxycycline-inducible ectopic Mitf-M expression on an Mitf-deficient Mitfmi-vga9 background (DMV mouse). Adult DMV mice were phenotypically characterized and tissues were collected for histology, immunohistochemistry, and evaluation of Mitf, pigmentary genes, and retinal pigment epithelium (RPE) gene expression. Results: Ectopic Mitf-M expression was specifically induced in the eyes, but was not detected in the skin of DMV mice. Inducible expression of Mitf-M partially rescued the microphthalmia, RPE structure, and pigmentation as well as a subset of the choroidal and iris melanocytes but not cutaneous melanocytes. RPE function and vision were not restored in the DMV mice. Conclusions: Ectopic expression of Mitf-M during development of Mitf-deficient mice is capable of partially rescuing ocular and retinal structures and uveal melanocytes. These findings provide novel information about the roles of Mitf isoforms in the development of mouse eyes.


Assuntos
Expressão Ectópica do Gene/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Fator de Transcrição Associado à Microftalmia/genética , Epitélio Pigmentado da Retina/metabolismo , Animais , Western Blotting , Corioide/citologia , Desenvolvimento Embrionário , Feminino , Perfilação da Expressão Gênica , Técnicas de Genotipagem , Imuno-Histoquímica , Oxirredutases Intramoleculares/farmacologia , Iris/citologia , Masculino , Melanócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microftalmia/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Pele/citologia
20.
PLoS Biol ; 16(5): e2003648, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29723194

RESUMO

Melanocyte stem cells (McSCs) and mouse models of hair graying serve as useful systems to uncover mechanisms involved in stem cell self-renewal and the maintenance of regenerating tissues. Interested in assessing genetic variants that influence McSC maintenance, we found previously that heterozygosity for the melanogenesis associated transcription factor, Mitf, exacerbates McSC differentiation and hair graying in mice that are predisposed for this phenotype. Based on transcriptome and molecular analyses of Mitfmi-vga9/+ mice, we report a novel role for MITF in the regulation of systemic innate immune gene expression. We also demonstrate that the viral mimic poly(I:C) is sufficient to expose genetic susceptibility to hair graying. These observations point to a critical suppressor of innate immunity, the consequences of innate immune dysregulation on pigmentation, both of which may have implications in the autoimmune, depigmenting disease, vitiligo.


Assuntos
Células-Tronco Adultas , Cor de Cabelo/imunologia , Imunidade Inata , Melanócitos , Fator de Transcrição Associado à Microftalmia/fisiologia , Animais , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Cor de Cabelo/genética , Interferon Tipo I/metabolismo , Camundongos , Camundongos Transgênicos , Poli I-C
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