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Genetic tools to target microglia specifically and efficiently from the early stages of embryonic development are lacking. We generated a constitutive Cre line controlled by the microglia signature gene Crybb1 that produced nearly complete recombination in embryonic brain macrophages (microglia and border-associated macrophages [BAMs]) by the perinatal period, with limited recombination in peripheral myeloid cells. Using this tool in combination with Flt3-Cre lineage tracer, single-cell RNA-sequencing analysis, and confocal imaging, we resolved embryonic-derived versus monocyte-derived BAMs in the mouse cortex. Deletion of the transcription factor SMAD4 in microglia and embryonic-derived BAMs using Crybb1-Cre caused a developmental arrest of microglia, which instead acquired a BAM specification signature. By contrast, the development of genuine BAMs remained unaffected. Our results reveal that SMAD4 drives a transcriptional and epigenetic program that is indispensable for the commitment of brain macrophages to the microglia fate and highlight Crybb1-Cre as a tool for targeting embryonic brain macrophages.
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Macrófagos , Microglia , Camundongos , Animais , Microglia/metabolismo , Macrófagos/metabolismo , Integrases/genética , Integrases/metabolismo , Encéfalo/metabolismoRESUMO
Fever, an evolutionarily conserved physiological response to infection, is also commonly associated with many autoimmune diseases, but its role in T cell differentiation and autoimmunity remains largely unclear. T helper 17 (Th17) cells are critical in host defense and autoinflammatory diseases, with distinct phenotypes and pathogenicity. Here, we show that febrile temperature selectively regulated Th17 cell differentiation in vitro in enhancing interleukin-17 (IL-17), IL-17F, and IL-22 expression. Th17 cells generated under febrile temperature (38.5°C-39.5°C), compared with those under 37°C, showed enhanced pathogenic gene expression with increased pro-inflammatory activities in vivo. Mechanistically, febrile temperature promoted SUMOylation of SMAD4 transcription factor to facilitate its nuclear localization; SMAD4 deficiency selectively abrogated the effects of febrile temperature on Th17 cell differentiation both in vitro and ameliorated an autoimmune disease model. Our results thus demonstrate a critical role of fever in shaping adaptive immune responses with implications in autoimmune diseases.
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Temperatura Corporal/imunologia , Febre/imunologia , Células Th17/imunologia , Imunidade Adaptativa , Animais , Diferenciação Celular/imunologia , Núcleo Celular/metabolismo , Citocinas/metabolismo , Encefalomielite Autoimune Experimental/genética , Encefalomielite Autoimune Experimental/imunologia , Febre/genética , Regulação da Expressão Gênica , Resposta ao Choque Térmico/imunologia , Camundongos , Proteína Smad4/deficiência , Proteína Smad4/metabolismo , Sumoilação , Células Th17/metabolismoRESUMO
Aortic aneurysms are life-threatening conditions with effective treatments mainly limited to emergency surgery or trans-arterial endovascular stent grafts, thus calling for the identification of specific molecular targets. Genetic studies have highlighted controversial roles of transforming growth factor ß (TGF-ß) signaling in aneurysm development. Here, we report on aneurysms developing in adult mice after smooth muscle cell (SMC)-specific inactivation of Smad4, an intracellular transducer of TGF-ß. The results revealed that Smad4 inhibition activated interleukin-1ß (IL-1ß) in SMCs. This danger signal later recruited innate immunity in the adventitia through chemokine (C-C motif) ligand 2 (CCL2) and modified the mechanical properties of the aortic wall, thus favoring vessel dilation. SMC-specific Smad4 deletion in Il1r1- or Ccr2-null mice resulted in milder aortic pathology. A chronic treatment with anti-IL-1ß antibody effectively hampered aneurysm development. These findings identify a mechanistic target for controlling the progression of aneurysms with compromised TGF-ß signaling, such as those driven by SMAD4 mutations.
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Aneurisma Aórtico/prevenção & controle , Interleucina-1beta/antagonistas & inibidores , Transdução de Sinais/fisiologia , Fator de Crescimento Transformador beta/fisiologia , Animais , Células Cultivadas , Quimiocina CCL2/antagonistas & inibidores , Interleucina-1beta/biossíntese , Camundongos , Miócitos de Músculo Liso/imunologia , NF-kappa B/fisiologia , Receptores CCR2/antagonistas & inibidores , Proteína Smad4/fisiologia , Tamoxifeno/farmacologiaRESUMO
Astrocytes regulate brain-wide functions and also show region-specific differences, but little is known about how general and region-specific functions are aligned at the single-cell level. To explore this, we isolated adult mouse diencephalic astrocytes by ACSA-2-mediated magnetic-activated cell sorting (MACS). Single-cell RNA-seq revealed 7 gene expression clusters of astrocytes, with 4 forming a supercluster. Within the supercluster, cells differed by gene expression related to ion homeostasis or metabolism, with the former sharing gene expression with other regions and the latter being restricted to specific regions. All clusters showed expression of proliferation-related genes, and proliferation of diencephalic astrocytes was confirmed by immunostaining. Clonal analysis demonstrated low level of astrogenesis in the adult diencephalon, but not in cerebral cortex grey matter. This led to the identification of Smad4 as a key regulator of diencephalic astrocyte in vivo proliferation and in vitro neurosphere formation. Thus, astrocytes show diverse gene expression states related to distinct functions with some subsets being more widespread while others are more regionally restricted. However, all share low-level proliferation revealing the novel concept of adult astrogenesis in the diencephalon.
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Astrócitos/metabolismo , Linhagem da Célula/genética , Diencéfalo/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Neurogênese/genética , Proteína Smad4/genética , Animais , Astrócitos/classificação , Astrócitos/citologia , Ciclo Celular/genética , Diferenciação Celular , Proliferação de Células , Córtex Cerebral/citologia , Córtex Cerebral/crescimento & desenvolvimento , Córtex Cerebral/metabolismo , Diencéfalo/citologia , Diencéfalo/crescimento & desenvolvimento , Ontologia Genética , Redes Reguladoras de Genes , Substância Cinzenta/citologia , Substância Cinzenta/crescimento & desenvolvimento , Substância Cinzenta/metabolismo , Redes e Vias Metabólicas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Anotação de Sequência Molecular , Família Multigênica , Transdução de Sinais , Proteína Smad4/metabolismoRESUMO
SMAD4 is a tumor suppressor mutated or silenced in multiple cancers, including oral cavity squamous cell carcinoma (OSCC). Human clinical samples and cell lines, mouse models and organoid culture were used to investigate the role that SMAD4 plays in progression from benign disease to invasive OSCC. Human OSCC lost detectable SMAD4 protein within tumor epithelium in 24% of cases, and this loss correlated with worse progression-free survival independent of other major clinical and pathological features. A mouse model engineered for KrasG12D expression in the adult oral epithelium induced benign papillomas, however the combination of KrasG12D with loss of epithelial Smad4 expression resulted in rapid development of invasive carcinoma with features of human OSCC. Examination of regulatory pathways in 3D organoid cultures of SMAD4+ and SMAD4- mouse tumors with Kras mutation found that either loss of SMAD4 or inhibition of TGFß signaling upregulated the WNT pathway and altered the extracellular matrix. The gene signature of the mouse tumor organoids lacking SMAD4 was highly similar to the gene signature of human head and neck squamous cell carcinoma. In summary, this work has uncovered novel mechanisms by which SMAD4 acts as a tumor suppressor in OSCC. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Progressão da Doença , Neoplasias Bucais , Proteína Smad4 , Via de Sinalização Wnt , Proteína Smad4/metabolismo , Proteína Smad4/genética , Humanos , Animais , Via de Sinalização Wnt/fisiologia , Neoplasias Bucais/patologia , Neoplasias Bucais/metabolismo , Neoplasias Bucais/genética , Camundongos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Linhagem Celular Tumoral , Mutação , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Masculino , Organoides/metabolismo , Organoides/patologiaRESUMO
BACKGROUND: Myhre syndrome is an exceedingly rare yet increasingly diagnosed genetic disorder arising from germline variants in the SMAD4 gene. Its core manifestation is the progression of stiffness and fibrosis across multiple organs. Individuals with Myhre syndrome exhibit a propensity for upper respiratory tract remodeling and infections. The molecular and cellular mechanisms underlying this phenotype remain unclear. OBJECTIVE: We sought to investigate how SMAD4 pathogenic variants associated with Myhre syndrome affect SMAD4 protein levels, activation, and physiological functions in patient-derived nasal epithelial cells. METHODS: Clinical observations were conducted on a cohort of 47 patients recruited at Massachusetts General Hospital from 2016 to 2023. Nasal epithelial basal cells were isolated and cultured from inferior turbinate brushings of healthy subjects (n = 8) and patients with Myhre syndrome (n = 3; SMAD4-Ile500Val, Arg496Cys, and Ile500Thr). Transcriptomic analysis and functional assays were performed to assess SMAD4 levels, transcriptional activity, and epithelial cell host defense functions, including cell proliferation, mucociliary differentiation, and bacterial elimination. RESULTS: Clinical observations revealed a prevalent history of otitis media and sinusitis among most individuals with Myhre syndrome. Analyses of nasal epithelial cells indicated that SMAD4 mutations do not alter SMAD4 protein stability or upstream regulatory SMAD phosphorylation but enhance signaling transcriptional activity, supporting a gain-of-function mechanism, likely attributable to increased protein-protein interaction of the SMAD complex. Consequently, Myhre syndrome nasal basal cells exhibit reduced potential in cell proliferation and mucociliary differentiation. Furthermore, Myhre syndrome nasal epithelia are impaired in bacterial killing. CONCLUSIONS: Compromised innate immunity originating from epithelial cells in Myhre syndrome may contribute to increased susceptibility to upper respiratory tract infections.
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SMAD4 constrains progression of Pten-null prostate cancer and serves as a common downstream node of transforming growth factor ß (TGFß) and bone morphogenetic protein (BMP) pathways. Here, we dissected the roles of TGFß receptor II (TGFBR2) and BMP receptor II (BMPR2) using a Pten-null prostate cancer model. These studies demonstrated that the molecular actions of TGFBR2 result in both SMAD4-dependent constraint of proliferation and SMAD4-independent activation of apoptosis. In contrast, BMPR2 deletion extended survival relative to Pten deletion alone, establishing its promoting role in BMP6-driven prostate cancer progression. These analyses reveal the complexity of TGFß-BMP signaling and illuminate potential therapeutic targets for prostate cancer.
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Receptores de Proteínas Morfogenéticas Ósseas Tipo II/genética , Receptores de Proteínas Morfogenéticas Ósseas Tipo II/metabolismo , Neoplasias da Próstata/fisiopatologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais , Animais , Neoplasias Ósseas/genética , Neoplasias Ósseas/secundário , Modelos Animais de Doenças , Deleção de Genes , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genótipo , Estimativa de Kaplan-Meier , Masculino , Camundongos , Camundongos Endogâmicos C57BL , PTEN Fosfo-Hidrolase/genética , Neoplasias da Próstata/genética , Receptor do Fator de Crescimento Transformador beta Tipo II , Proteína Smad4/genética , Proteína Smad4/metabolismoRESUMO
BACKGROUND: During embryogenesis, cardiac neural crest-derived cells (NCs) migrate into the pharyngeal arches and give rise to the vascular smooth muscle cells (vSMCs) of the pharyngeal arch arteries (PAAs). vSMCs are critical for the remodeling of the PAAs into their final adult configuration, giving rise to the aortic arch and its arteries (AAAs). RESULTS: We investigated the role of SMAD4 in NC-to-vSMC differentiation using lineage-specific inducible mouse strains. We found that the expression of SMAD4 in the NC is indelible for regulating the survival of cardiac NCs. Although the ablation of SMAD4 at E9.5 in the NC lineage led to a near-complete absence of NCs in the pharyngeal arches, PAAs became invested with vSMCs derived from a compensatory source. Analysis of AAA development at E16.5 showed that the alternative vSMC source compensated for the lack of NC-derived vSMCs and rescued AAA morphogenesis. CONCLUSIONS: Our studies uncovered the requisite role of SMAD4 in the contribution of the NC to the pharyngeal arch mesenchyme. We found that in the absence of SMAD4+ NCs, vSMCs around the PAAs arose from a different progenitor source, rescuing AAA morphogenesis. These findings shed light on the remarkable plasticity of developmental mechanisms governing AAA development.
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Músculo Liso Vascular , Crista Neural , Animais , Camundongos , Aorta , Aorta Torácica , Região Branquial , Músculo Liso Vascular/metabolismoRESUMO
To explore the underlying molecular mechanisms of supraventricular tachycardia (SVT), this study aimed to analyse the complex relationship between FLRT3 and TGF-ß/SMAD4 signalling pathway, which affects Na+ and K+ channels in cardiomyocytes. Bioinformatics analysis was performed on 85 SVT samples and 15 healthy controls to screen overlapping genes from the key module and differentially expressed genes (DEGs). Expression profiling of overlapping genes, coupled with Receiver Operating Characteristic (ROC) curve analyses, identified FLRT3 as a hub gene. In vitro studies utilizing Ang II-stimulated H9C2 cardiomyocytes were undertaken to elucidate the consequences of FLRT3 silencing on cardiomyocyte apoptosis and autophagic processes. Utilizing a combination of techniques such as quantitative reverse-transcription polymerase chain reaction (qRT-PCR), western blotting (WB), flow cytometry, dual-luciferase reporter assays and chromatin immunoprecipitation polymerase chain reaction (ChIP-PCR) assays were conducted to decipher the intricate interactions between FLRT3, the TGF-ß/SMAD4 signalling cascade and ion channel gene expression. Six genes (AADAC, DSC3, FLRT3, SYT4, PRR9 and SERTM1) demonstrated reduced expression in SVT samples, each possessing significant clinical diagnostic potential. In H9C2 cardiomyocytes, FLRT3 silencing mitigated Ang II-induced apoptosis and modulated autophagy. With increasing TGF-ß concentration, there was a dose-responsive decline in FLRT3 and SCN5A expression, while both KCNIP2 and KCND2 expressions were augmented. Moreover, a direct interaction between FLRT3 and SMAD4 was observed, and inhibition of SMAD4 expression resulted in increased FLRT3 expression. Our results demonstrated that the TGF-ß/SMAD4 signalling pathway plays a critical role by regulating FLRT3 expression, with potential implications for ion channel function in SVT.
Assuntos
Apoptose , Glicoproteínas de Membrana , Proteína Smad4 , Taquicardia Supraventricular , Fator de Crescimento Transformador beta , Humanos , Apoptose/genética , Autofagia/genética , Western Blotting , Glicoproteínas de Membrana/metabolismo , Proteína Smad4/metabolismo , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismoRESUMO
The present review demonstrates the major tumor suppressor genes, including TP53, CDKN2A and SMAD4, associated with pancreatic cancer. Each gene's role, prevalence and impact on tumor development and progression are analyzed, focusing on the intricate molecular landscape of pancreatic cancer. In addition, this review underscores the prognostic significance of specific mutations, such as loss of TP53, and explores some potential targeted therapies tailored to these molecular signatures. The findings highlight the importance of genomic analyses for risk assessment, early detection and the design of personalized treatment approaches in pancreatic cancer. Overall, this review provides a comprehensive analysis of the molecular intricacies of pancreatic tumors, paving the way for more effective and tailored therapeutic interventions.
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Advocacy support groups grow into national and international organizations, but they all begin with personal experiences. As the parents to a newly diagnosed two-year-old son with Myhre syndrome, my husband and I were overwhelmed with the journey ahead. Thanks to networking, primarily through social media, we located other families living with Myhre syndrome and were quickly immersed in the challenges and joy of this community. Myhre syndrome, caused by pathogenic missense variants in SMAD4, is a rare connective tissue disease characterized by short stature, hearing loss, neurodevelopmental challenges, and fibroproliferation. This personal essay, written with physician partners, describes the development of a global advocacy group for patients with Myhre syndrome. I have the honor of serving as the founding Executive Director and reflect proudly on the great strides that our marvelous support group has made. We empower the global community impacted by this rare condition by providing meaningful and accessible data, educational opportunities, and connections with others going through similar experiences. Utilizing the expertise of our Board of Directors and my corporate expertise, we discuss how we have been able to elevate our ultra-rare community into a broader, more comprehensive network.
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BACKGROUND: In select patients, pancreatic adenocarcinoma remains a local disease, yet there are no validated biomarkers to predict this behavior and who may benefit from aggressive local treatments. This study sought to determine if SMAD4 (mothers against decapentaplegic homolog 4) messenger RNA-sequencing (RNA-seq) expression is a robust method for predicting overall survival (OS) and distant metastasis-free survival (DMFS) in patients with resected pancreatic adenocarcinoma. METHODS: Utilizing The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC), 322 patients with resected stage I-III pancreatic adenocarcinoma were identified. In TCGA, multivariable proportional hazards models were used to determine the association of SMAD4 genomic aberrations and RNA-seq expression with OS and DMFS. In the ICGC, analysis sought to confirm the predictive performance of RNA-seq via multivariable models and receiver operator characteristic curves. RESULTS: In TCGA, the presence of SMAD4 genomic aberrations was associated with worse OS (hazard ratio [HR], 1.55; 95% CI, 1.00-2.40; p = .048) but not DMFS (HR, 1.33; 95% CI, .87-2.03; p = .19). Low SMAD4 RNA-seq expression was associated with worse OS (HR, 1.83; 95% CI, 1.17-2.86; p = .008) and DMFS (HR, 1.70; 95% CI, 1.14-2.54; p = .009). In the ICGC, increased SMAD4 RNA-seq expression correlated with improved OS (area under the curve [AUC], .92; 95% CI, .86-.94) and DMFS (AUC, .84; 95% CI, .82-.87). CONCLUSIONS: In patients with resected pancreatic adenocarcinoma, SMAD4 genomic aberrations are associated with worse OS but do not predict for DMFS. Increased SMAD4 RNA-seq expression is associated with improved OS and DMFS in patients with resected pancreatic adenocarcinoma. This reproducible finding suggests SMAD4 RNA-seq expression may be a useful marker to predict metastatic spread.
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Adenocarcinoma , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/cirurgia , Neoplasias Pancreáticas/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/cirurgia , Proteína Smad4/genética , Modelos de Riscos Proporcionais , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , PrognósticoRESUMO
Smad4, a critical mediator of TGF-ß signaling, plays a pivotal role in regulating various cellular functions, including immune responses. In this study, we investigated the impact of Smad4 knockout specifically in macrophages on anti-tumor immunity, focusing on lung metastasis of B16 melanoma cells. Using a mouse model with Smad4 knockout in macrophages established via Lyz2-cre mice and Smad4 flox/flox mice, we demonstrated a significant inhibition of B16 metastasis in the lungs. Interestingly, the inhibition of tumor growth was found to be independent of adaptive immunity, as no significant changes were observed in the numbers or activities of T cells, B cells, or NK cells. Instead, Smad4 knockout led to the emergence of an MCHIIlow CD206high subset of lung interstitial macrophages, characterized by enhanced phagocytosis function. Our findings highlight the crucial role of Smad4 in modulating the innate immune response against tumors and provide insights into potential therapeutic strategies targeting lung interstitial macrophages to enhance anti-tumor immunity.
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Neoplasias Pulmonares , Melanoma Experimental , Fagocitose , Proteína Smad4 , Animais , Camundongos , Linhagem Celular Tumoral , Pulmão/patologia , Pulmão/imunologia , Pulmão/metabolismo , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Macrófagos/imunologia , Macrófagos/metabolismo , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/patologia , Melanoma Experimental/patologia , Melanoma Experimental/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fagocitose/genética , Proteína Smad4/deficiência , Proteína Smad4/genética , Proteína Smad4/metabolismoRESUMO
SMAD4 regulates gene expression in response to BMP and TGFß signal transduction, and is required for diverse morphogenetic processes, but its target genes have remained largely elusive. Here, we identify the SMAD4 target genes in mouse limb buds using an epitope-tagged Smad4 allele for ChIP-seq analysis in combination with transcription profiling. This analysis shows that SMAD4 predominantly mediates BMP signal transduction during early limb bud development. Unexpectedly, the expression of cholesterol biosynthesis enzymes is precociously downregulated and intracellular cholesterol levels are reduced in Smad4-deficient limb bud mesenchymal progenitors. Most importantly, our analysis reveals a predominant function of SMAD4 in upregulating target genes in the anterior limb bud mesenchyme. Analysis of differentially expressed genes shared between Smad4- and Shh-deficient limb buds corroborates this function of SMAD4 and also reveals the repressive effect of SMAD4 on posterior genes that are upregulated in response to SHH signaling. This analysis uncovers opposing trans-regulatory inputs from SHH- and SMAD4-mediated BMP signal transduction on anterior and posterior gene expression during the digit patterning and outgrowth in early limb buds.
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Padronização Corporal , Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas Hedgehog/metabolismo , Botões de Extremidades/embriologia , Transdução de Sinais , Proteína Smad4/metabolismo , Animais , Proteínas Morfogenéticas Ósseas/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Hedgehog/genética , Membro Posterior/embriologia , Camundongos , Camundongos Transgênicos , Proteína Smad4/genéticaRESUMO
We investigated the effects of transcriptional intermediary factor 1γ (TIF1γ) and SMAD4 on the proliferation and liver metastasis of colorectal cancer (CRC) cells through knockdown of TIF1γ and/or SMAD4 and knockdown of TIF1γ and/or restoration of SMAD4 expression. Furthermore, we examined TIF1γ and SMAD4 expression in human primary CRC and corresponding liver metastatic CRC specimens. TIF1γ promoted but SMAD4 inhibited the proliferation of CRC cells by competitively binding to activated SMAD2/SMAD3 complexes and then reversely regulating c-Myc, p21, p27, and cyclinA2 levels. Surprisingly, both TIF1γ and SMAD4 reduced the liver metastasis of all studied CRC cell lines via inhibition of MEK/ERK pathway-mediated COX-2, Nm23, uPA, and MMP9 expression. In patients with advanced CRC, reduced TIF1γ or SMAD4 expression was correlated with increased invasion and liver metastasis and was a significant, independent risk factor for recurrence and survival after radical resection. Patients with advanced CRC with reduced TIF1γ or SAMD4 expression had higher recurrence rates and shorter overall survival. TIF1γ and SMAD4 competitively exert contrasting effects on cell proliferation but act complementarily to suppress the liver metastasis of CRC via MEK/ERK pathway inhibition. Thus, reduced TIF1γ or SMAD4 expression in advanced CRC predicts earlier liver metastasis and poor prognosis.
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Neoplasias Colorretais , Neoplasias Hepáticas , Humanos , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/patologia , Neoplasias Hepáticas/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteína Smad4 , Fatores de Transcrição/metabolismoRESUMO
Lung squamous cell carcinoma (LUSC) is one of the most common malignant tumors of the respiratory. Pyroptosis plays an essential role in cancer, but there is limited research investigating pyroptosis in LUSC. In this study, pyroptosis-related genes were observed to have extensive multiomics alterations in LUSC through analysis of the TCGA database. Utilizing machine learning for selection and verifying expression levels, GSDMC was chosen as the critical gene for further experiments. Our research found that GSDMC is overexpressed in LUSC tissues and cells, and is associated with poor prognosis. Knockdown of GSDMC in LUSC inhibits cell proliferation, invasion, metastasis, chemotherapeutic sensitivity, and reduced tumor formation in nude mice, accompanied by downregulation of proliferative and EMT-related protein expression. However, these effects were counteracted in cells where GSDMC is overexpressed. Mechanistically, the oncogenic role of GSDMC is primarily achieved through the activation of the AKT/mTOR pathway, and this effect can be significantly reversed by rapamycin. Finally, SMAD4's interaction with the promoter region of GSDMC results in the suppression of GSDMC expression. In summary, our study through bioinformatics and experimental approaches not only proves that SMAD4 regulates the protumorigenic role of GSDMC through transcriptional targeting, but also indicates the possibility of developing the SMAD4/GSDMC/AKT/mTOR signaling axis as a potential biomarker and treatment target for LUSC.
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Carcinoma de Células Escamosas , Proliferação de Células , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares , Camundongos Nus , Proteínas Proto-Oncogênicas c-akt , Piroptose , Transdução de Sinais , Serina-Treonina Quinases TOR , Humanos , Serina-Treonina Quinases TOR/metabolismo , Serina-Treonina Quinases TOR/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Animais , Prognóstico , Camundongos , Piroptose/genética , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Carcinoma de Células Escamosas/metabolismo , Linhagem Celular Tumoral , Progressão da Doença , Feminino , Masculino , Proteína Smad4/genética , Proteína Smad4/metabolismo , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismoRESUMO
BACKGROUND: In our previous investigation, we revealed a significant increase in the expression of microRNA-6881-3p (miR-6881-3p) in follicular fluid granulosa cells (GCs) from women with diminished ovarian reserve (DOR) compared to those with normal ovarian reserve (NOR). However, the role of miR-6881-3p in the development of DOR remains poorly understood. OBJECTIVE: This study aimed to elucidate the involvement of miR-6881-3p in the regulation of granulosa cells (GCs) function and the pathogenesis of DOR. MATERIALS AND METHODS: Initially, we assessed the expression levels of miR-6881-3p in GCs obtained from human follicular fluid in both NOR and DOR cases and explored the correlation between miR-6881-3p expression and clinical outcomes in assisted reproduction technology (ART). Bioinformatic predictions and dual-luciferase reporter assays were employed to identify the target gene of miR-6881-3p. Manipulation of miR-6881-3p expression was achieved through the transfection of KGN cells with miR-6881-3p mimics, inhibitor, and miRNA negative control (NC). Following transfection, we assessed granulosa cell apoptosis and cell cycle progression via flow cytometry and quantified target gene expression through quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot (WB) analysis. Finally, we examined the correlation between target gene expression levels in GCs from NOR and DOR patients and their association with ART outcomes. RESULTS: Our findings revealed elevated miR-6881-3p levels in GCs from DOR patients, which negatively correlated with ovarian reserve function and ART outcomes. We identified a direct binding interaction between miR-6881-3p and the 3'-untranslated region of the SMAD4. Transfection with miR-6881-3p mimics induced apoptosis in KGN cell. Furthermore, miR-6881-3p expression negatively correlated with both mRNA and protein levels of the SMAD4. The mRNA and protein levels of SMAD4 were notably reduced in GCs from DOR patients, and SMAD4 mRNA expression positively correlated with ART outcomes. In addition, the mRNA levels of FSHR, CYP11A1 were notably reduced after transfection with miR-6881-3p mimics in KGN cell, while LHCGR notably increased. The mRNA and protein levels of FSHR, CYP11A1 were notably reduced in GCs from DOR patients, while LHCGR notably increased. CONCLUSION: This study underscores the role of miR-6881-3p in directly targeting SMAD4 mRNA, subsequently diminishing granulosa cell viability and promoting apoptosis, and may affect steroid hormone regulation and gonadotropin signal reception in GCs. These findings contribute to our understanding of the pathogenesis of DOR.
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MicroRNAs , Doenças Ovarianas , Reserva Ovariana , Humanos , Feminino , Reserva Ovariana/genética , Enzima de Clivagem da Cadeia Lateral do Colesterol/metabolismo , MicroRNAs/metabolismo , Doenças Ovarianas/metabolismo , Células da Granulosa/metabolismo , Apoptose/genética , RNA Mensageiro/metabolismo , Proliferação de Células/genética , Proteína Smad4/metabolismoRESUMO
Uganda is a developing low-income country with a low incidence of colorectal cancer, which is steadily increasing. Ugandan colorectal cancer (CRC) patients are young and present with advanced-stage disease. In our population, there is a scarcity of genetic oncological studies, therefore, we investigated the mutational status of CRC tissues, focusing in particular on the adenomatous polyposis coli (APC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), and SMAD4 genes. Our objective was to determine whether there were any differences between other populations and Ugandan patients. We performed next-generation sequencing on the extracted DNA from formalin-fixed paraffin-embedded adenocarcinoma samples from 127 patients (mean (SD) age: 54.9 (16.0) years; male:female sex ratio: 1.2:1). Most tumours were located in the rectum 56 (44.1%), 14 (11%) tumours were high grade, and 96 (75.6%) were moderate grade CRC. Stage III + IV CRC tumours were found in 109 (85.8%) patients. We identified 48 variants of APC, including 9 novel APC mutations that were all pathogenic or deleterious. For PIK3CA, we found 19 variants, of which 9 were deleterious or pathogenic. Four PIK3CA novel pathogenic or deleterious variants were included (c.1397C > G, c.2399_2400insA, c.2621G > C, c.2632C > G). Three SMAD4 variants were reported, including two pathogenic or deleterious variants (c.1268G > T, c.556dupC) and one tolerant (c.563A > C) variant. One novel SMAD4 deleterious mutation (c.1268G > T) was reported. In conclusion, we provide clinicopathological information and new genetic variation data pertinent to CRC in Uganda.
Assuntos
Proteína da Polipose Adenomatosa do Colo , Classe I de Fosfatidilinositol 3-Quinases , Neoplasias Colorretais , Mutação , Proteína Smad4 , Humanos , Proteína Smad4/genética , Masculino , Feminino , Classe I de Fosfatidilinositol 3-Quinases/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Pessoa de Meia-Idade , Uganda/epidemiologia , Adulto , Idoso , Proteína da Polipose Adenomatosa do Colo/genética , Sequenciamento de Nucleotídeos em Larga EscalaRESUMO
In female mammals, the oviduct and uterus are essential sites for female and male gamete transport, fertilization, implantation, and maintenance of a successful pregnancy. To delineate the reproductive function of Mothers against decapentaplegic homolog 4 (Smad4), we specifically inactivated Smad4 in ovarian granulosa cells and, oviduct and uterine mesenchymal cells using the Amhr2-cre mouse line. Deletion of exon 8 of Smad4 results in the production of an MH2-truncated SMAD4 protein. These mutant mice are infertile due to the development of oviductal diverticula and defects during the implantation process. The ovaries are fully functional as demonstrated in an ovary transfer experiment. The development of oviductal diverticula occurs shortly after puberty and is dependent on estradiol. The diverticula interfere with sperm migration and embryo transit to the uterus, reducing the number of implantation sites. Analysis of the uterus shows that, even if implantation occurs, decidualization and vascularization are defective resulting in embryo resorption as early as the seventh day of pregnancy. Thus, Smad4 plays an important function in female reproduction by controlling the structural and functional integrity of the oviduct and uterus.
Assuntos
Estradiol , Proteína Smad4 , Animais , Feminino , Humanos , Masculino , Camundongos , Gravidez , Implantação do Embrião , Estradiol/metabolismo , Mamíferos/metabolismo , Oviductos/metabolismo , Sêmen/metabolismo , Proteína Smad4/genética , Proteína Smad4/metabolismo , Útero/metabolismoRESUMO
Hepcidin negatively regulates systemic iron levels by inhibiting iron entry into the circulation. Hepcidin production is increased in response to an increase in systemic iron via the activation of the bone morphogenetic protein (BMP) pathway. Regulation of hepcidin expression by iron status has been proposed on the basis of evidence mainly from rodents and humans. We evaluated the effect of iron administration on plasma hepcidin concentrations in calves and the expression of bovine hepcidin by the BMP pathway in a cell culture study. Hematocrit as well as levels of blood hemoglobin and plasma iron were lower than the reference level in calves aged 1-4 weeks. Although intramuscular administration of iron increased iron-related parameters, plasma hepcidin concentrations were unaffected. Treatment with BMP6 increased hepcidin expression in human liver-derived cells but not in bovine liver-derived cells. A luciferase-based reporter assay revealed that Smad4 was required for hepcidin reporter transcription induced by Smad1. The reporter activity of hepcidin was lower in the cells transfected with bovine Smad4 than in those transfected with murine Smad4. The lower expression levels of bovine Smad4 were responsible for the lower activity of the hepcidin reporter, which might be due to the instability of bovine Smad4 mRNA. In fact, the endogenous Smad4 protein levels were lower in bovine cells than in human and murine cells. Smad4 also confers TGF-ß/activin-mediated signaling. Induction of TGF-ß-responsive genes was also lower after treatment with TGF-ß1 in bovine hepatocytes than in human hepatoma cells. We revealed the unique regulation of bovine hepcidin expression and the characteristic TGF-ß family signaling mediated by bovine Smad4. The present study suggests that knowledge of the regulatory expression of hepcidin as well as TGF-ß family signaling obtained in murine and human cells is not always applicable to bovine cells.