RESUMO
Inhibitors of poly(ADP-ribose) (PAR) polymerase (PARPi) have entered the clinic for the treatment of homologous recombination (HR)-deficient cancers. Despite the success of this approach, preclinical and clinical research with PARPi has revealed multiple resistance mechanisms, highlighting the need for identification of novel functional biomarkers and combination treatment strategies. Functional genetic screens performed in cells and organoids that acquired resistance to PARPi by loss of 53BP1 identified loss of LIG3 as an enhancer of PARPi toxicity in BRCA1-deficient cells. Enhancement of PARPi toxicity by LIG3 depletion is dependent on BRCA1 deficiency but independent of the loss of 53BP1 pathway. Mechanistically, we show that LIG3 loss promotes formation of MRE11-mediated post-replicative ssDNA gaps in BRCA1-deficient and BRCA1/53BP1 double-deficient cells exposed to PARPi, leading to an accumulation of chromosomal abnormalities. LIG3 depletion also enhances efficacy of PARPi against BRCA1-deficient mammary tumors in mice, suggesting LIG3 as a potential therapeutic target.
Assuntos
Proteína BRCA1/genética , DNA Ligase Dependente de ATP/genética , DNA de Cadeia Simples , Proteína Homóloga a MRE11/genética , Neoplasias Ovarianas/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Proteínas de Ligação a Poli-ADP-Ribose/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética , Animais , Biópsia , Sistemas CRISPR-Cas , Linhagem Celular , Núcleo Celular/metabolismo , Proliferação de Células , Aberrações Cromossômicas , Dano ao DNA , DNA Ligase Dependente de ATP/metabolismo , Feminino , Humanos , Lentivirus/genética , Neoplasias Mamárias Animais , Camundongos , Mutação , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , RNA Interferente Pequeno/metabolismo , TransgenesRESUMO
Somatic hotspot mutations and structural amplifications and fusions that affect fibroblast growth factor receptor 2 (encoded by FGFR2) occur in multiple types of cancer1. However, clinical responses to FGFR inhibitors have remained variable1-9, emphasizing the need to better understand which FGFR2 alterations are oncogenic and therapeutically targetable. Here we apply transposon-based screening10,11 and tumour modelling in mice12,13, and find that the truncation of exon 18 (E18) of Fgfr2 is a potent driver mutation. Human oncogenomic datasets revealed a diverse set of FGFR2 alterations, including rearrangements, E1-E17 partial amplifications, and E18 nonsense and frameshift mutations, each causing the transcription of E18-truncated FGFR2 (FGFR2ΔE18). Functional in vitro and in vivo examination of a compendium of FGFR2ΔE18 and full-length variants pinpointed FGFR2-E18 truncation as single-driver alteration in cancer. By contrast, the oncogenic competence of FGFR2 full-length amplifications depended on a distinct landscape of cooperating driver genes. This suggests that genomic alterations that generate stable FGFR2ΔE18 variants are actionable therapeutic targets, which we confirmed in preclinical mouse and human tumour models, and in a clinical trial. We propose that cancers containing any FGFR2 variant with a truncated E18 should be considered for FGFR-targeted therapies.
Assuntos
Éxons , Deleção de Genes , Terapia de Alvo Molecular , Neoplasias , Oncogenes , Inibidores de Proteínas Quinases , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Animais , Éxons/genética , Humanos , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/patologia , Oncogenes/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/antagonistas & inibidores , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismoRESUMO
Genetically engineered mouse models (GEMMs) of cancer have proven to be of great value for basic and translational research. Although CRISPR-based gene disruption offers a fast-track approach for perturbing gene function and circumvents certain limitations of standard GEMM development, it does not provide a flexible platform for recapitulating clinically relevant missense mutations in vivo. To this end, we generated knock-in mice with Cre-conditional expression of a cytidine base editor and tested their utility for precise somatic engineering of missense mutations in key cancer drivers. Upon intraductal delivery of sgRNA-encoding vectors, we could install point mutations with high efficiency in one or multiple endogenous genes in situ and assess the effect of defined allelic variants on mammary tumorigenesis. While the system also produces bystander insertions and deletions that can stochastically be selected for when targeting a tumor suppressor gene, we could effectively recapitulate oncogenic nonsense mutations. We successfully applied this system in a model of triple-negative breast cancer, providing the proof of concept for extending this flexible somatic base editing platform to other tissues and tumor types.
Assuntos
Neoplasias da Mama/genética , Sistemas CRISPR-Cas , Edição de Genes , Animais , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Transgênicos , MutaçãoRESUMO
Given the relevance of beige adipocytes in adult humans, a better understanding of the molecular circuits involved in beige adipocyte biogenesis has provided new insight into human brown adipocyte biology. Genetic mutations in SLC39A13/ZIP13, a member of zinc transporter family, are known to reduce adipose tissue mass in humans; however, the underlying mechanisms remains unknown. Here, we demonstrate that the Zip13-deficient mouse shows enhanced beige adipocyte biogenesis and energy expenditure, and shows ameliorated diet-induced obesity and insulin resistance. Both gain- and loss-of-function studies showed that an accumulation of the CCAAT/enhancer binding protein-ß (C/EBP-ß) protein, which cooperates with dominant transcriptional co-regulator PR domain containing 16 (PRDM16) to determine brown/beige adipocyte lineage, is essential for the enhanced adipocyte browning caused by the loss of ZIP13. Furthermore, ZIP13-mediated zinc transport is a prerequisite for degrading the C/EBP-ß protein to inhibit adipocyte browning. Thus, our data reveal an unexpected association between zinc homeostasis and beige adipocyte biogenesis, which may contribute significantly to the development of new therapies for obesity and metabolic syndrome.
Assuntos
Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Ligação a DNA/genética , Obesidade/genética , Fatores de Transcrição/genética , Adipócitos Bege/metabolismo , Adipogenia/genética , Animais , Proteínas de Transporte de Cátions/metabolismo , Linhagem da Célula , Proteínas de Ligação a DNA/metabolismo , Dieta Hiperlipídica , Metabolismo Energético/genética , Humanos , Resistência à Insulina/genética , Camundongos , Camundongos Knockout , Obesidade/metabolismo , Obesidade/patologia , Fatores de Transcrição/metabolismo , Zinco/metabolismoRESUMO
Skin tissues, in particular the epidermis, are severely affected by zinc deficiency. However, the zinc-mediated mechanisms that maintain the cells that form the epidermis have not been established. Here, we report that the zinc transporter ZIP10 is highly expressed in the outer root sheath of hair follicles and plays critical roles in epidermal development. We found that ZIP10 marked epidermal progenitor cell subsets and that ablating Zip10 caused significant epidermal hypoplasia accompanied by down-regulation of the transactivation of p63, a master regulator of epidermal progenitor cell proliferation and differentiation. Both ZIP10 and p63 are significantly increased during epidermal development, in which ZIP10-mediated zinc influx promotes p63 transactivation. Collectively, these results indicate that ZIP10 plays important roles in epidermal development via, at least in part, the ZIP10-zinc-p63 signaling axis, thereby highlighting the physiological significance of zinc regulation in the maintenance of skin epidermis.
Assuntos
Proteínas de Transporte de Cátions/genética , Folículo Piloso/metabolismo , Homeostase/genética , Fosfoproteínas/genética , Pele/metabolismo , Transativadores/genética , Zinco/metabolismo , Animais , Proteínas de Transporte de Cátions/metabolismo , Cátions Bivalentes , Diferenciação Celular , Proliferação de Células , Embrião de Mamíferos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Folículo Piloso/crescimento & desenvolvimento , Células HeLa , Humanos , Transporte de Íons , Camundongos , Camundongos Transgênicos , Fosfoproteínas/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Pele/citologia , Pele/crescimento & desenvolvimento , Técnicas de Cultura de Tecidos , Transativadores/metabolismoRESUMO
A critical component of the DNA damage response is the p53 tumor suppressor, and aberrant p53 function leads to uncontrolled cell proliferation and malignancy. Several molecules have been shown to regulate p53 stability; however, genome-wide systemic approaches for determining the affected, specific downstream target genes have not been extensively studied. Here, we first identified an orphan nuclear receptor, RORα, as a direct target gene of p53, which contains functional p53 response elements. The functional consequences of DNA damage-induced RORα are to stabilize p53 and activate p53 transcription in a HAUSP/Usp7-dependent manner. Interestingly, microarray analysis revealed that RORα-mediated p53 stabilization leads to the activation of a subset of p53 target genes that are specifically involved in apoptosis. We further confirmed that RORα enhances p53-dependent, in vivo apoptotic function in the Drosophila model system. Together, we determined that RORα is a p53 regulator that exerts its role in increased apoptosis via p53.
Assuntos
Apoptose , Dano ao DNA , Membro 1 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Membro 1 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Estabilidade Proteica , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/genética , Drosophila melanogaster/citologia , Drosophila melanogaster/metabolismo , Regiões Promotoras Genéticas/genética , Elementos de Resposta/genética , Ubiquitina Tiolesterase/metabolismo , UbiquitinaçãoRESUMO
The regulation of melanin production is important for managing skin darkness and hyperpigmentary disorders. Numerous anti-melanogenic agents that target tyrosinase activity/stability, melanosome maturation/transfer, or melanogenesis-related signaling pathways have been developed. As a rate-limiting enzyme in melanogenesis, tyrosinase has been the most attractive target, but tyrosinase-targeted treatments still pose serious potential risks, indicating the necessity of developing lower-risk anti-melanogenic agents. Sugars are ubiquitous natural compounds found in humans and other organisms. Here, we review the recent advances in research on the roles of sugars and sugar-related agents in melanogenesis and in the development of sugar-based anti-melanogenic agents. The proposed mechanisms of action of these agents include: (a) (natural sugars) disturbing proper melanosome maturation by inducing osmotic stress and inhibiting the PI3 kinase pathway and (b) (sugar derivatives) inhibiting tyrosinase maturation by blocking N-glycosylation. Finally, we propose an alternative strategy for developing anti-melanogenic sugars that theoretically reduce melanosomal pH by inhibiting a sucrose transporter and reduce tyrosinase activity by inhibiting copper incorporation into an active site. These studies provide evidence of the utility of sugar-based anti-melanogenic agents in managing skin darkness and curing pigmentary disorders and suggest a future direction for the development of physiologically favorable anti-melanogenic agents.
Assuntos
Carboidratos/química , Carboidratos/farmacologia , Melaninas/antagonistas & inibidores , Melaninas/metabolismo , Pigmentação da Pele/efeitos dos fármacos , Animais , Antígenos de Neoplasias/metabolismo , Humanos , Proteínas de Membrana Transportadoras/metabolismoRESUMO
Pontin is a chromatin remodeling factor that possesses both ATPase and DNA helicase activities. Although Pontin is frequently overexpressed in human cancers of various types and implicated in oncogenic functions, the upstream signaling network leading to the regulation of Pontin that in turn affects transcription of downstream target genes has not been extensively studied. Here, we identify Pontin is methylated by G9a/GLP methyltransferases in hypoxic condition and potentiates HIF-1α-mediated activation by increasing the recruitment of p300 coactivator to a subset of HIF-1α target promoters. Intriguingly, Pontin methylation results in the increased invasive and migratory properties by activating downstream target gene, Ets1. In contrast, inhibition of Pontin methylation results in the suppression of tumorigenic and metastatic properties. Together, our data provide new approaches by targeting Pontin methylation and its downstream targets for the development of therapeutic agents for human cancers.
Assuntos
Proteínas de Transporte/metabolismo , Montagem e Desmontagem da Cromatina , DNA Helicases/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , ATPases Associadas a Diversas Atividades Celulares , Hipóxia Celular , Linhagem Celular Tumoral , Cromatina/genética , Epigenômica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Metilação , Metiltransferases/metabolismo , Proteínas de Neoplasias/metabolismo , Transcrição GênicaRESUMO
BRCA1 and BRCA2 both function in DNA double-strand break repair by homologous recombination (HR). Due to their HR defect, BRCA1/2-deficient cancers are sensitive to poly(ADP-ribose) polymerase inhibitors (PARPis), but they eventually acquire resistance. Preclinical studies yielded several PARPi resistance mechanisms that do not involve BRCA1/2 reactivation, but their relevance in the clinic remains elusive. To investigate which BRCA1/2-independent mechanisms drive spontaneous resistance in vivo, we combine molecular profiling with functional analysis of HR of matched PARPi-naive and PARPi-resistant mouse mammary tumors harboring large intragenic deletions that prevent reactivation of BRCA1/2. We observe restoration of HR in 62% of PARPi-resistant BRCA1-deficient tumors but none in the PARPi-resistant BRCA2-deficient tumors. Moreover, we find that 53BP1 loss is the prevalent resistance mechanism in HR-proficient BRCA1-deficient tumors, whereas resistance in BRCA2-deficient tumors is mainly induced by PARG loss. Furthermore, combined multi-omics analysis identifies additional genes and pathways potentially involved in modulating PARPi response.
Assuntos
Neoplasias , Neoplasias Ovarianas , Animais , Camundongos , Feminino , Humanos , Proteína BRCA1/genética , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Multiômica , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Neoplasias/genética , Neoplasias Ovarianas/genéticaRESUMO
Targeting the PI3K-AKT-mTOR pathway is a promising therapeutic strategy for breast cancer treatment. However, low response rates and development of resistance to PI3K-AKT-mTOR inhibitors remain major clinical challenges. Here, we show that MYC activation drives resistance to mTOR inhibitors (mTORi) in breast cancer. Multiomic profiling of mouse invasive lobular carcinoma (ILC) tumors revealed recurrent Myc amplifications in tumors that acquired resistance to the mTORi AZD8055. MYC activation was associated with biological processes linked to mTORi response and counteracted mTORi-induced translation inhibition by promoting translation of ribosomal proteins. In vitro and in vivo induction of MYC conferred mTORi resistance in mouse and human breast cancer models. Conversely, AZD8055-resistant ILC cells depended on MYC, as demonstrated by the synergistic effects of mTORi and MYCi combination treatment. Notably, MYC status was significantly associated with poor response to everolimus therapy in metastatic breast cancer patients. Thus, MYC is a clinically relevant driver of mTORi resistance that may stratify breast cancer patients for mTOR-targeted therapies.
Assuntos
Neoplasias da Mama , Humanos , Animais , Camundongos , Feminino , Neoplasias da Mama/tratamento farmacológico , Inibidores de MTOR , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Serina-Treonina Quinases TORRESUMO
The limited efficacy of immune checkpoint inhibitor treatment in triple-negative breast cancer (TNBC) patients is attributed to sparse or unresponsive tumor-infiltrating lymphocytes, but the mechanisms that lead to a therapy resistant tumor immune microenvironment are incompletely known. Here we show a strong correlation between MYC expression and loss of immune signatures in human TNBC. In mouse models of TNBC proficient or deficient of breast cancer type 1 susceptibility gene (BRCA1), MYC overexpression dramatically decreases lymphocyte infiltration in tumors, along with immune signature remodelling. MYC-mediated suppression of inflammatory signalling induced by BRCA1/2 inactivation is confirmed in human TNBC cell lines. Moreover, MYC overexpression prevents the recruitment and activation of lymphocytes in both human and mouse TNBC co-culture models. Chromatin-immunoprecipitation-sequencing reveals that MYC, together with its co-repressor MIZ1, directly binds promoters of multiple interferon-signalling genes, resulting in their downregulation. MYC overexpression thus counters tumor growth inhibition by a Stimulator of Interferon Genes (STING) agonist via suppressing induction of interferon signalling. Together, our data reveal that MYC suppresses innate immunity and facilitates tumor immune escape, explaining the poor immunogenicity of MYC-overexpressing TNBCs.
Assuntos
Neoplasias de Mama Triplo Negativas , Animais , Humanos , Camundongos , Linhagem Celular Tumoral , Interferons , Linfócitos do Interstício Tumoral , Transdução de Sinais , Neoplasias de Mama Triplo Negativas/metabolismo , Microambiente Tumoral/genética , Proteínas Proto-Oncogênicas c-myc/metabolismoRESUMO
Neural stem cells (NSCs) are self-renewing, multipotent cells that can generate neurons, astrocytes, and oligodendrocytes of the nervous system. NSCs have been extensively studied because they can be used to treat impaired cells and tissues or improve regenerative power of degenerating cells in neurodegenerative diseases or spinal cord injuries. For successful clinical applications of NSCs, it is essential to understand the mechanisms underlying self-renewal and differentiation of NSCs, which involve complex interplays among key factors including transcription factors, epigenetic control, microRNAs, and signaling pathways. Despite numerous studies on such factors, a holistic view of their interplays during neural development still remains elusive. In this review, we present recently identified potential regulatory factors and their targets by genomics and proteomics technologies and then integrate them into regulatory networks that describe their complex interplays to achieve self-renewal and differentiation of NSCs.
Assuntos
Neurônios/citologia , Neurônios/fisiologia , Células-Tronco/citologia , Células-Tronco/fisiologia , Transcrição Gênica/fisiologia , Animais , Diferenciação Celular , Proliferação de CélulasRESUMO
Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1Flox/Flox;Trp53Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1-/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.
Assuntos
Neoplasias da Mama , Carcinoma Lobular , Animais , Neoplasias da Mama/tratamento farmacológico , Carcinoma Lobular/tratamento farmacológico , Feminino , Humanos , Sistema Imunitário , Camundongos , Fosfatidilinositol 3-Quinases , Serina-Treonina Quinases TOR/genéticaRESUMO
We report proteogenomic analysis of diffuse gastric cancers (GCs) in young populations. Phosphoproteome data elucidated signaling pathways associated with somatic mutations based on mutation-phosphorylation correlations. Moreover, correlations between mRNA and protein abundances provided potential oncogenes and tumor suppressors associated with patient survival. Furthermore, integrated clustering of mRNA, protein, phosphorylation, and N-glycosylation data identified four subtypes of diffuse GCs. Distinguishing these subtypes was possible by proteomic data. Four subtypes were associated with proliferation, immune response, metabolism, and invasion, respectively; and associations of the subtypes with immune- and invasion-related pathways were identified mainly by phosphorylation and N-glycosylation data. Therefore, our proteogenomic analysis provides additional information beyond genomic analyses, which can improve understanding of cancer biology and patient stratification in diffuse GCs.
Assuntos
Redes Reguladoras de Genes , Mutação , Proteogenômica/métodos , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Idade de Início , Feminino , Glicosilação , Humanos , Masculino , Fosforilação , Mapas de Interação de Proteínas , Análise de Sobrevida , Sequenciamento do Exoma/métodosRESUMO
Selective elimination of BRCA1-deficient cells by inhibitors of poly(ADP-ribose) polymerase (PARP) is a prime example of the concept of synthetic lethality in cancer therapy. This interaction is counteracted by the restoration of BRCA1-independent homologous recombination through loss of factors such as 53BP1, RIF1, and REV7/MAD2L2, which inhibit end resection of DNA double-strand breaks (DSBs). To identify additional factors involved in this process, we performed CRISPR/SpCas9-based loss-of-function screens and selected for factors that confer PARP inhibitor (PARPi) resistance in BRCA1-deficient cells. Loss of members of the CTC1-STN1-TEN1 (CST) complex were found to cause PARPi resistance in BRCA1-deficient cells in vitro and in vivo. We show that CTC1 depletion results in the restoration of end resection and that the CST complex may act downstream of 53BP1/RIF1. These data suggest that, in addition to its role in protecting telomeres, the CST complex also contributes to protecting DSBs from end resection.
Assuntos
Proteína BRCA1/deficiência , Quebras de DNA de Cadeia Dupla , Complexos Multiproteicos/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Animais , Proteína BRCA1/metabolismo , Sistemas CRISPR-Cas/genética , Linhagem Celular Tumoral , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Camundongos , Células-Tronco Embrionárias Murinas/efeitos dos fármacos , Células-Tronco Embrionárias Murinas/metabolismo , Telômero/metabolismoRESUMO
Obesity is a major risk factor for developing nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common form of chronic liver disease and is closely associated with insulin resistance, ultimately leading to cirrhosis and hepatocellular carcinoma. However, knowledge of the intracellular regulators of obesity-linked fatty liver disease remains incomplete. Here we showed that hepatic Rho-kinase 1 (ROCK1) drives obesity-induced steatosis in mice through stimulation of de novo lipogenesis. Mice lacking ROCK1 in the liver were resistant to diet-induced obesity owing to increased energy expenditure and thermogenic gene expression. Constitutive expression of hepatic ROCK1 was sufficient to promote adiposity, insulin resistance, and hepatic lipid accumulation in mice fed a high-fat diet. Correspondingly, liver-specific ROCK1 deletion prevented the development of severe hepatic steatosis and reduced hyperglycemia in obese diabetic (ob/ob) mice. Of pathophysiological significance, hepatic ROCK1 was markedly upregulated in humans with fatty liver disease and correlated with risk factors clustering around NAFLD and insulin resistance. Mechanistically, we found that hepatic ROCK1 suppresses AMPK activity and a ROCK1/AMPK pathway is necessary to mediate cannabinoid-induced lipogenesis in the liver. Furthermore, treatment with metformin, the most widely used antidiabetes drug, reduced hepatic lipid accumulation by inactivating ROCK1, resulting in activation of AMPK downstream signaling. Taken together, our findings establish a ROCK1/AMPK signaling axis that regulates de novo lipogenesis, providing a unique target for treating obesity-related metabolic disorders such as NAFLD.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Lipogênese , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/enzimologia , Hipernutrição/enzimologia , Transdução de Sinais , Quinases Associadas a rho/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Humanos , Resistência à Insulina/genética , Fígado/patologia , Masculino , Camundongos , Camundongos Knockout , Camundongos Obesos , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/patologia , Obesidade/complicações , Obesidade/genética , Obesidade/metabolismo , Obesidade/patologia , Hipernutrição/complicações , Hipernutrição/genética , Hipernutrição/patologia , Quinases Associadas a rho/genéticaRESUMO
Melanocytes play an important role in maintaining epidermal homeostasis by producing melanin and protecting the skin from harmful environmental factors. However, excessive up- or down-regulation of melanin production often causes hyper- or hypo-pigmented disorders, respectively, which affect the patient's quality of life. Therefore, various strategies for modulating melanin levels have been developed by the pharmaceutical and cosmetic industries. We reported previously that voglibose, which is a well-known anti-hyperglycemic agent, could be used as an anti-melanogenic agent by inhibiting α-glucosidase activity and reducing tyrosinase protein levels. Of the other representative anti-hyperglycemic agents, acarbose showed less anti-melanogenic activity despite its potent anti-hyperglycemic efficacy. In this study, we report that acarbose exhibited considerable anti-melanogenic activity when melanocytes were co-treated with acarbose and a digestible sugar, such as maltose. Simultaneous treatment with maltose augmented the inhibitory effect of acarbose on α-glucosidase activity by enhancing its stability under physiological conditions, leading to the down-regulation of tyrosinase. These results suggest that the co-treatment of anti-hyperglycemic agents with hydrolysable sugars may be a useful tool for reducing glucosidase-associated melanogenesis as a potent sugar-based anti-melanogenic regimen.
Assuntos
Acarbose/farmacologia , Inibidores de Glicosídeo Hidrolases/farmacologia , Hipoglicemiantes/farmacologia , Maltose/farmacologia , Melaninas/biossíntese , Pigmentação da Pele/efeitos dos fármacos , alfa-Glucosidases/metabolismo , Linhagem Celular , Sinergismo Farmacológico , Humanos , Melanócitos/metabolismoRESUMO
Spermatogonial stem cells (SSCs) are germline stem cells located along the basement membrane of seminiferous tubules in testes. Recently, SSCs were shown to be reprogrammed into multipotent SSCs (mSSCs). However, both the key factors and biological networks underlying this reprogramming remain elusive. Here, we present transcriptional regulatory networks (TRNs) that control cellular processes related to the SSC-to-mSSC reprogramming. Previously, we established intermediate SSCs (iSSCs) undergoing the transition to mSSCs and generated gene expression profiles of SSCs, iSSCs and mSSCs. By comparing these profiles, we identified 2643 genes that were up-regulated during the reprogramming process and 15 key transcription factors (TFs) that regulate these genes. Using the TF-target relationships, we developed TRNs describing how these TFs regulate three pluripotency-related processes (cell proliferation, stem cell maintenance and epigenetic regulation) during the reprogramming. The TRNs showed that 4 of the 15 TFs (Oct4/Pou5f1, Cux1, Zfp143 and E2f4) regulated cell proliferation during the early stages of reprogramming, whereas 11 TFs (Oct4/Pou5f1, Foxm1, Cux1, Zfp143, Trp53, E2f4, Esrrb, Nfyb, Nanog, Sox2 and Klf4) regulated the three pluripotency-related processes during the late stages of reprogramming. Our TRNs provide a model for the temporally coordinated transcriptional regulation of pluripotency-related processes during the SSC-to-mSSC reprogramming, which can be further tested in detailed functional studies.
Assuntos
Reprogramação Celular , Redes Reguladoras de Genes , Células-Tronco Pluripotentes/citologia , Espermatogônias/citologia , Animais , Proliferação de Células/genética , Humanos , Fator 4 Semelhante a Kruppel , Masculino , Camundongos , Células-Tronco Pluripotentes/metabolismo , Espermatogônias/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Regulação para CimaRESUMO
Skin is the first area that manifests zinc deficiency. However, the molecular mechanisms by which zinc homeostasis affects skin development remain largely unknown. Here, we show that zinc-regulation transporter-/iron-regulation transporter-like protein 7 (ZIP7) localized to the endoplasmic reticulum plays critical roles in connective tissue development. Mice lacking the Slc39a7/Zip7 gene in collagen 1-expressing tissue exhibited dermal dysplasia. Ablation of ZIP7 in mesenchymal stem cells inhibited cell proliferation thereby preventing proper dermis formation, indicating that ZIP7 is required for dermal development. We also found that mesenchymal stem cells lacking ZIP7 accumulated zinc in the endoplasmic reticulum, which triggered zinc-dependent aggregation and inhibition of protein disulfide isomerase, leading to endoplasmic reticulum dysfunction. These results suggest that ZIP7 is necessary for endoplasmic reticulum function in mesenchymal stem cells and, as such, is essential for dermal development.