RESUMEN

The dysregulation of circadian rhythm oscillation is a prominent feature of various solid tumors. Thus, clarifying the molecular mechanisms that maintain the circadian clock is important. In the present study, we revealed that the transcription factor forkhead box FOXK1 functions as an oncogene in breast cancer. We showed that FOXK1 recruits multiple transcription corepressor complexes, including NCoR/SMRT, SIN3A, NuRD, and REST/CoREST. Among them, the FOXK1/NCoR/SIN3A complex transcriptionally regulates a cohort of genes, including CLOCK, PER2, and CRY2, that are critically involved in the circadian rhythm. The complex promoted the proliferation of breast cancer cells by disturbing the circadian rhythm oscillation. Notably, the nuclear expression of FOXK1 was positively correlated with tumor grade. Insulin resistance gradually became more severe with tumor progression and was accompanied by the increased expression of OGT, which caused the nuclear translocation and increased expression of FOXK1. Additionally, we found that metformin downregulates FOXK1 and exports it from the nucleus, while HDAC inhibitors (HDACi) inhibit the FOXK1-related enzymatic activity. Combined treatment enhanced the expression of circadian clock genes through the regulation of FOXK1, thereby exerting an antitumor effect, indicating that highly nuclear FOXK1-expressing breast cancers are potential candidates for the combined application of metformin and HDACi.

Asunto(s)

Neoplasias de la Mama , Ritmo Circadiano , Factores de Transcripción Forkhead , Regulación Neoplásica de la Expresión Génica , Resistencia a la Insulina , Humanos , Neoplasias de la Mama/patología , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Animales , Ritmo Circadiano/genética , Criptocromos/genética , Criptocromos/metabolismo , Complejo Correpresor Histona Desacetilasa y Sin3/genética , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Proteínas CLOCK/genética , Proteínas CLOCK/metabolismo , Proteínas Circadianas Period/genética , Proteínas Circadianas Period/metabolismo , Proliferación Celular , Línea Celular Tumoral , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Inhibidores de Histona Desacetilasas/farmacología , Ratones , Carcinogénesis/genética , Células MCF-7 , Ratones Desnudos

RESUMEN

Nuclear receptor action is mediated in part by the nuclear receptor corepressor 1 (NCOR1) and the silencing mediator of retinoic acid and thyroid hormone receptor (SMRT). NCOR1 and SMRT regulate metabolic pathways that govern body mass, insulin sensitivity, and energy expenditure, representing an understudied area in the realm of metabolic health and disease. Previously, we found that NCOR1 and SMRT are essential for maintaining metabolic homeostasis and their knockout (KO) leads to rapid weight loss and hypoglycemia, which is not survivable. Because of a potential defect in glucose absorption, we sought to determine the role of NCOR1 and SMRT specifically in intestinal epithelial cells (IECs). We used a postnatal strategy to disrupt NCOR1 and SMRT throughout IECs in adult mice. These mice were characterized metabolically and underwent metabolic phenotyping, body composition analysis, and glucose tolerance testing. Jejunal IECs were isolated and profiled by bulk RNA sequencing. We found that the postnatal KO of NCOR1 and SMRT from IECs leads to rapid weight loss and hypoglycemia with a significant reduction in survival. This was accompanied by alterations in glucose metabolism and activation of fatty acid oxidation in IECs. Metabolic phenotyping confirmed a reduction in body mass driven by a loss of body fat without altered food intake. This appeared to be mediated by a reduction of key intestinal carbohydrate transporters, including SGLT1, GLUT2, and GLUT5. Intestinal NCOR1 and SMRT act in tandem to regulate glucose levels and body weight. This in part may be mediated by regulation of intestinal carbohydrate transporters.

Asunto(s)

Mucosa Intestinal , Ratones Noqueados , Co-Represor 1 de Receptor Nuclear , Co-Represor 2 de Receptor Nuclear , Animales , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 2 de Receptor Nuclear/metabolismo , Co-Represor 2 de Receptor Nuclear/genética , Ratones , Mucosa Intestinal/metabolismo , Glucosa/metabolismo , Masculino , Metabolismo de los Hidratos de Carbono/genética , Ratones Endogámicos C57BL , Transportador 1 de Sodio-Glucosa/metabolismo , Transportador 1 de Sodio-Glucosa/genética , Transporte Biológico , Femenino , Metabolismo Energético , Transportador de Glucosa de Tipo 2/metabolismo , Transportador de Glucosa de Tipo 2/genética

RESUMEN

Histone deacetylase 3 (HDAC3) is a crucial epigenetic modulator essential for various developmental and physiological functions. Although its dysfunction is increasingly recognized in abnormal phenotypes, to our knowledge, there have been no established reports of human diseases directly linked to HDAC3 dysfunction. Using trio exome sequencing and extensive phenotypic analysis, we correlated heterozygous de novo variants in HDAC3 with a neurodevelopmental disorder having variable clinical presentations, frequently associated with intellectual disability, developmental delay, epilepsy, and musculoskeletal abnormalities. In a cohort of six individuals, we identified missense variants in HDAC3 (c.277G>A [p.Asp93Asn], c.328G>A [p.Ala110Thr], c.601C>T [p.Pro201Ser], c. 797T>C [p.Leu266Ser], c.799G>A [p.Gly267Ser], and c.1075C>T [p.Arg359Cys]), all located in evolutionarily conserved sites and confirmed as de novo. Experimental studies identified defective deacetylation activity in the p.Asp93Asn, p.Pro201Ser, p.Leu266Ser, and p.Gly267Ser variants, positioned near the enzymatic pocket. In addition, proteomic analysis employing co-immunoprecipitation revealed that the disrupted interactions with molecules involved in the CoREST and NCoR complexes, particularly in the p.Ala110Thr variant, consist of a central pathogenic mechanism. Moreover, immunofluorescence analysis showed diminished nuclear to cytoplasmic fluorescence ratio in the p.Ala110Thr, p.Gly267Ser, and p.Arg359Cys variants, indicating impaired nuclear localization. Taken together, our study highlights that de novo missense variants in HDAC3 are associated with a broad spectrum of neurodevelopmental disorders, which emphasizes the complex role of HDAC3 in histone deacetylase activity, multi-protein complex interactions, and nuclear localization for proper physiological functions. These insights open new avenues for understanding the molecular mechanisms of HDAC3-related disorders and may inform future therapeutic strategies.

Asunto(s)

Epigénesis Genética , Histona Desacetilasas , Mutación Missense , Trastornos del Neurodesarrollo , Humanos , Histona Desacetilasas/genética , Histona Desacetilasas/metabolismo , Mutación Missense/genética , Trastornos del Neurodesarrollo/genética , Masculino , Femenino , Preescolar , Niño , Discapacidad Intelectual/genética , Secuenciación del Exoma , Adolescente , Discapacidades del Desarrollo/genética , Fenotipo , Lactante , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 1 de Receptor Nuclear/metabolismo

RESUMEN

Long-term memory formation requires de novo RNA and protein synthesis. Using differential display PCR, we found that the NCoR1 cDNA fragment is differentially expressed between fast learners and slow learners, with fast learners showing a lower expression level than slow learners in the water maze learning task. Fast learners also show lower NCoR1 mRNA and protein expression levels. In addition, spatial training decreases both NCoR1 mRNA and protein expression, whereas NCoR1 conditional knockout (cKO) mice show enhanced spatial memory. In studying the molecular mechanism, we found that spatial training decreases the association between NCoR1 and DEC2. Both NCoR1 and DEC2 suppress the expression of BDNF, integrin α3 and SGK1 through C/EBPα binding to their DNA promoters, but overexpression of DEC2 in NCoR1 cKO mice rescues the decreased expression of these proteins compared with NCoR1 loxP mice overexpressing DEC2. Further, spatial training decreases DEC2 expression. Spatial training also enhances C/EBPα binding to Bdnf, Itga3 and Sgk1 promoters, an effect also observed in fast learners, and both NCoR1 and DEC2 control C/EBPα activity. Whereas knockdown of BDNF, integrin α3 or SGK1 expression impairs spatial learning and memory, it does not affect Y-maze performance, suggesting that BDNF, integrin α3 and SGK1 are involved in long-term memory formation, but not short-term memory formation. Moreover, NCoR1 expression is regulated by the JNK/c-Jun signaling pathway. Collectively, our findings identify DEC2 as a novel interacting protein of NCoR1 and elucidate the novel roles and mechanisms of NCoR1 and DEC2 in negative regulation of spatial memory formation.

Asunto(s)

Aprendizaje por Laberinto , Ratones Noqueados , Co-Represor 1 de Receptor Nuclear , Memoria Espacial , Animales , Memoria Espacial/fisiología , Ratones , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Aprendizaje por Laberinto/fisiología , Masculino , Ratones Endogámicos C57BL , Regiones Promotoras Genéticas , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Proteínas Serina-Treonina Quinasas , Proteínas Inmediatas-Precoces

RESUMEN

G protein pathway suppressor 2 (GPS2) has been shown to play a pivotal role in human and mouse definitive erythropoiesis in an EKLF-dependent manner. However, whether GPS2 affects human primitive erythropoiesis is still unknown. This study demonstrated that GPS2 positively regulates erythroid differentiation in K562 cells, which have a primitive erythroid phenotype. Overexpression of GPS2 promoted hemin-induced hemoglobin synthesis in K562 cells as assessed by the increased percentage of benzidine-positive cells and the deeper red coloration of the cell pellets. In contrast, knockdown of GPS2 inhibited hemin-induced erythroid differentiation of K562 cells. GPS2 overexpression also enhanced erythroid differentiation of K562 cells induced by cytosine arabinoside (Ara-C). GPS2 induced hemoglobin synthesis by increasing the expression of globin and ALAS2 genes, either under steady state or upon hemin treatment. Promotion of erythroid differentiation of K562 cells by GPS2 mainly relies on NCOR1, as knockdown of NCOR1 or lack of the NCOR1-binding domain of GPS2 potently diminished the promotive effect. Thus, our study revealed a previously unknown role of GPS2 in regulating human primitive erythropoiesis in K562 cells.

Asunto(s)

Diferenciación Celular , Eritropoyesis , Hemina , Leucemia Eritroblástica Aguda , Co-Represor 1 de Receptor Nuclear , Humanos , 5-Aminolevulinato Sintetasa/genética , 5-Aminolevulinato Sintetasa/metabolismo , Células Eritroides/metabolismo , Células Eritroides/citología , Eritropoyesis/genética , Técnicas de Silenciamiento del Gen , Hemina/farmacología , Hemoglobinas/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Células K562 , Leucemia Eritroblástica Aguda/patología , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/genética , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética

RESUMEN

Class II histone deacetylases (HDACs) are important in regulation of gene transcription during T cell development. However, our understanding of their cell-specific functions is limited. In this study, we reveal that class IIa Hdac4 and Hdac7 (Hdac4/7) are selectively induced in transcription, guiding the lineage-specific differentiation of mouse T-helper 17 (Th17) cells from naive CD4+ T cells. Importantly, Hdac4/7 are functionally dispensable in other Th subtypes. Mechanistically, Hdac4 interacts with the transcription factor (TF) JunB, facilitating the transcriptional activation of Th17 signature genes such as Il17a/f. Conversely, Hdac7 collaborates with the TF Aiolos and Smrt/Ncor1-Hdac3 corepressors to repress transcription of Th17 negative regulators, including Il2, in Th17 cell differentiation. Inhibiting Hdac4/7 through pharmacological or genetic methods effectively mitigates Th17 cell-mediated intestinal inflammation in a colitis mouse model. Our study uncovers molecular mechanisms where HDAC4 and HDAC7 function distinctively yet cooperatively in regulating ordered gene transcription during Th17 cell differentiation. These findings suggest a potential therapeutic strategy of targeting HDAC4/7 for treating Th17-related inflammatory diseases, such as ulcerative colitis.

Asunto(s)

Diferenciación Celular , Colitis , Histona Desacetilasas , Co-Represor 1 de Receptor Nuclear , Células Th17 , Animales , Células Th17/citología , Células Th17/metabolismo , Células Th17/inmunología , Histona Desacetilasas/metabolismo , Histona Desacetilasas/genética , Ratones , Colitis/genética , Colitis/metabolismo , Colitis/inmunología , Transcripción Genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Co-Represor 2 de Receptor Nuclear/metabolismo , Co-Represor 2 de Receptor Nuclear/genética , Interleucina-17/metabolismo , Regulación de la Expresión Génica , Ratones Endogámicos C57BL , Humanos , Proteínas Represoras/metabolismo , Proteínas Represoras/genética , Interleucina-2/metabolismo

RESUMEN

Nuclear receptor corepressors (NCoRs) function in multiprotein complexes containing histone deacetylase 3 (HDAC3) to alter transcriptional output primarily through repressive chromatin remodelling at target loci1-5. In the liver, loss of HDAC3 causes a marked hepatosteatosis largely because of de-repression of genes involved in lipid metabolism6,7; however, the individual roles and contribution of other complex members to hepatic and systemic metabolic regulation are unclear. Here we show that adult loss of both NCoR1 and NCoR2 (double knockout (KO)) in hepatocytes phenocopied the hepatomegalic fatty liver phenotype of HDAC3 KO. In addition, double KO livers exhibited a dramatic reduction in glycogen storage and gluconeogenic gene expression that was not observed with hepatic KO of individual NCoRs or HDAC3, resulting in profound fasting hypoglycaemia. This surprising HDAC3-independent activation function of NCoR1 and NCoR2 is due to an unexpected loss of chromatin accessibility on deletion of NCoRs that prevented glucocorticoid receptor binding and stimulatory effect on gluconeogenic genes. These studies reveal an unanticipated, non-canonical activation function of NCoRs that is required for metabolic health.

Asunto(s)

Gluconeogénesis , Histona Desacetilasas , Hígado , Ratones Noqueados , Co-Represor 1 de Receptor Nuclear , Co-Represor 2 de Receptor Nuclear , Receptores de Glucocorticoides , Gluconeogénesis/genética , Animales , Receptores de Glucocorticoides/metabolismo , Receptores de Glucocorticoides/genética , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Ratones , Histona Desacetilasas/metabolismo , Histona Desacetilasas/genética , Co-Represor 2 de Receptor Nuclear/metabolismo , Co-Represor 2 de Receptor Nuclear/genética , Hígado/metabolismo , Hepatocitos/metabolismo , Coactivador 2 del Receptor Nuclear/metabolismo , Coactivador 2 del Receptor Nuclear/genética

Asunto(s)

Hígado , Co-Represor 1 de Receptor Nuclear , Co-Represor 2 de Receptor Nuclear , Receptores de Glucocorticoides , Receptores de Glucocorticoides/metabolismo , Hígado/metabolismo , Humanos , Animales , Co-Represor 1 de Receptor Nuclear/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 2 de Receptor Nuclear/metabolismo , Co-Represor 2 de Receptor Nuclear/genética , Ratones

RESUMEN

OBJECTIVE: To explore the genetic background for a patient with refractory myelodysplastic/myeloproliferative neoplasm (MDS/MPN) with co-morbid neutrophilia patient. METHODS: A MDS/MPN patient who was admitted to the First Affiliated Hospital of Nanjing Medical University in May 2021 was selected as the study subject. RNA sequencing was carried out to identify fusion genes in his peripheral blood mononuclear cells. Fusion gene sequence was searched through transcriptome-wide analysis with a STAR-fusion procedure. The novel fusion genes were verified by quantitative real-time PCR and Sanger sequencing. RESULTS: The patient, a 67-year-old male, had progressive thrombocytopenia. Based on the morphological and molecular examinations, he was diagnosed as MDS/MPN with co-morbid neutropenia, and was treated with demethylating agents and Bcl-2 inhibitors. Seventeen months after the diagnosis, he had progressed to AML. A novel fusion gene NCOR1::GLYR1 was identified by RNA-sequencing in his peripheral blood sample, which was verified by quantitative real-time PCR and Sanger sequencing. The patient had attained morphological remission after a DCAG regimen (a combinatory chemotherapy of decitabine, cytarabine, aclarubicin and granulocyte colony-stimulating factors) plus Chidamide treatment. A significant decrease in the NCOR1::GLYR1 expression was revealed by quantitative real-time PCR at post-chemotherapy evaluation. CONCLUSION: NCOR1::GLYR1 gene is considered as the pathogenic factor for the MDS/MPN patient with neutropenia.

Asunto(s)

Leucemia Mieloide Aguda , Síndromes Mielodisplásicos , Neutropenia , Masculino , Humanos , Anciano , Síndromes Mielodisplásicos/genética , Leucocitos Mononucleares , Citarabina/uso terapéutico , Co-Represor 1 de Receptor Nuclear

RESUMEN

Despite numerous female contraceptive options, nearly half of all pregnancies are unintended. Family planning choices for men are currently limited to unreliable condoms and invasive vasectomies with questionable reversibility. Here, we report the development of an oral contraceptive approach based on transcriptional disruption of cyclical gene expression patterns during spermatogenesis. Spermatogenesis involves a continuous series of self-renewal and differentiation programs of spermatogonial stem cells (SSCs) that is regulated by retinoic acid (RA)-dependent activation of receptors (RARs), which control target gene expression through association with corepressor proteins. We have found that the interaction between RAR and the corepressor silencing mediator of retinoid and thyroid hormone receptors (SMRT) is essential for spermatogenesis. In a genetically engineered mouse model that negates SMRT-RAR binding (SMRTmRID mice), the synchronized, cyclic expression of RAR-dependent genes along the seminiferous tubules is disrupted. Notably, the presence of an RA-resistant SSC population that survives RAR de-repression suggests that the infertility attributed to the loss of SMRT-mediated repression is reversible. Supporting this notion, we show that inhibiting the action of the SMRT complex with chronic, low-dose oral administration of a histone deacetylase inhibitor reversibly blocks spermatogenesis and fertility without affecting libido. This demonstration validates pharmacologic targeting of the SMRT repressor complex for non-hormonal male contraception.

Asunto(s)

Proteínas de Unión al ADN , Proteínas Represoras , Humanos , Femenino , Masculino , Animales , Ratones , Proteínas de Unión al ADN/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Proteínas Co-Represoras/genética , Co-Represor 2 de Receptor Nuclear/genética , Tretinoina/farmacología , Anticoncepción , Co-Represor 1 de Receptor Nuclear

RESUMEN

Introduction: Pluripotent stem cells can be generated from somatic cells by the Yamanaka factors Oct4, Sox2, Klf4 and c-Myc. Methods: Mouse embryonic fibroblasts (MEFs) were transduced with the Yamanaka factors and generation of induced pluripotent stem cells (iPSCs) was assessed by formation of alkaline phosphatase positive colonies, pluripotency gene expression and embryod bodies formation. Results: The thyroid hormone triiodothyronine (T3) enhances MEFs reprogramming. T3-induced iPSCs resemble embryonic stem cells in terms of the expression profile and DNA methylation pattern of pluripotency genes, and of their potential for embryod body formation and differentiation into the three major germ layers. T3 induces reprogramming even though it increases expression of the cyclin kinase inhibitors p21 and p27, which are known to oppose acquisition of pluripotency. The actions of T3 on reprogramming are mainly mediated by the thyroid hormone receptor beta and T3 can enhance iPSC generation in the absence of c-Myc. The hormone cannot replace Oct4 on reprogramming, but in the presence of T3 is possible to obtain iPSCs, although with low efficiency, without exogenous Klf4. Furthermore, depletion of the corepressor NCoR (or Nuclear Receptor Corepressor 1) reduces MEFs reprogramming in the absence of the hormone and strongly decreases iPSC generation by T3 and also by 9cis-retinoic acid, a well-known inducer of reprogramming. NCoR depletion also markedly antagonizes induction of pluripotency gene expression by both ligands. Conclusions: Inclusion of T3 on reprogramming strategies has a potential use in enhancing the generation of functional iPSCs for studies of cell plasticity, disease and regenerative medicine.

Asunto(s)

Reprogramación Celular , Co-Represor 1 de Receptor Nuclear , Células Madre Pluripotentes , Animales , Ratones , Proteínas Co-Represoras/genética , Fibroblastos/metabolismo , Hormonas/metabolismo , Células Madre Pluripotentes/metabolismo , Hormonas Tiroideas/metabolismo , Co-Represor 1 de Receptor Nuclear/genética

RESUMEN

BACKGROUND/AIM: B-cell lymphomas are characterized by diverse genetic anomalies affecting B-cell differentiation. To expand targeted therapies, an in-depth grasp of the molecular dynamics in the germinal center (GC) is vital. Transducin ß-like 1 X-linked receptor 1 (TBL1XR1) and nuclear receptor corepressor 1 (NCOR1) are instrumental within the GC, modulating myriad oncogenic pathways. Their prognostic roles in various cancers are established, yet their precise impact on B-cell lymphoma is elusive. MATERIALS AND METHODS: Digital RNA quantification (Nanostring) of previously curated 188 B-cell lymphoma specimens across four subtypes, follicular lymphoma (FL), diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS), primary testicular lymphoma (PTL), and plasmablastic lymphoma (PBL), was reanalyzed with focus on TBL1XR1 and NCOR1 expression, juxtaposing them with 730 ontogenically linked genes. RESULTS: Notably, TBL1XR1 expression was significantly elevated in the PTL- ABC-subtype versus DLBCL-NOS- ABC-subtype (p<0.001), with no marked disparity in GCB-subtypes between them. The median TBL1XR1 expression was remarkably diminished in FL, yet, intriguingly, GCB-subtypes of DLBCL-NOS exhibited significantly enhanced expression compared to FL (p=0.001). In contrast, NCOR1's expression trajectory was consistent across DLBCL-NOS, PTL, and PBL. A strong inverse correlation between TBL1XR1 and NCOR1 was observed in PBL (p=0.001). Importantly, TBL1XR1's pronounced association with several DNA Damage repair (DDR) genes was noted suggesting influence on DNA repair. TBL1XR1-DDR gene signature was further validated employing a public data set of DLBCL-NOS. CONCLUSION: Our exploratory findings unravel the expression patterns of TBL1XR1/NCOR1 in B-cell lymphoma variants. The TBL1XR1-DDR genes connection offers insights into potential DNA repair roles, paving avenues for innovative therapies in B-cell lymphomas.

Asunto(s)

Linfoma Folicular , Linfoma de Células B Grandes Difuso , Linfoma Plasmablástico , Humanos , Linfoma de Células B Grandes Difuso/genética , Reparación del ADN , Daño del ADN , Proteínas Represoras/genética , Receptores Citoplasmáticos y Nucleares/genética , Co-Represor 1 de Receptor Nuclear/genética

RESUMEN

The nuclear receptor co-repressor (NCoR) complex mediates transcriptional repression dependent on histone deacetylation by histone deacetylase 3 (HDAC3) as a component of the complex. Unexpectedly, we found that signaling by the receptor activator of nuclear factor κB (RANK) converts the NCoR/HDAC3 co-repressor complex to a co-activator of AP-1 and NF-κB target genes that are required for mouse osteoclast differentiation. Accordingly, the dominant function of NCoR/HDAC3 complexes in response to RANK signaling is to activate, rather than repress, gene expression. Mechanistically, RANK signaling promotes RNA-dependent interaction of the transcriptional co-activator PGC1ß with the NCoR/HDAC3 complex, resulting in the activation of PGC1ß and inhibition of HDAC3 activity for acetylated histone H3. Non-coding RNAs Dancr and Rnu12, which are associated with altered human bone homeostasis, promote NCoR/HDAC3 complex assembly and are necessary for RANKL-induced osteoclast differentiation in vitro. These findings may be prototypic for signal-dependent functions of NCoR in other biological contexts.

Asunto(s)

Osteoclastos , ARN , Humanos , Ratones , Animales , Proteínas Co-Represoras/genética , Osteoclastos/metabolismo , Ligando RANK/genética , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 1 de Receptor Nuclear/metabolismo , Expresión Génica

RESUMEN

PPARα corepressor NCoR1 is a key regulator of fatty acid ß-oxidation and ketogenesis. However, its regulatory mechanism is largely unknown. Here, we report that oncoprotein p21-activated kinase 4 (PAK4) is an NCoR1 kinase. Specifically, PAK4 phosphorylates NCoR1 at T1619/T2124, resulting in an increase in its nuclear localization and interaction with PPARα, thereby repressing the transcriptional activity of PPARα. We observe impaired ketogenesis and increases in PAK4 protein and NCoR1 phosphorylation levels in liver tissues of high fat diet-fed mice, NAFLD patients, and hepatocellular carcinoma patients. Forced overexpression of PAK4 in mice represses ketogenesis and thereby increases hepatic fat accumulation, whereas genetic ablation or pharmacological inhibition of PAK4 exhibites an opposite phenotype. Interestingly, PAK4 protein levels are significantly suppressed by fasting, largely through either cAMP/PKA- or Sirt1-mediated ubiquitination and proteasome degradation. In this way, our findings provide evidence for a PAK4-NCoR1/PPARα signaling pathway that regulates fatty acid ß-oxidation and ketogenesis.

Asunto(s)

Ácidos Grasos , PPAR alfa , Quinasas p21 Activadas , Animales , Ratones , Proteínas Co-Represoras , Ácidos Grasos/metabolismo , Quinasas p21 Activadas/genética , PPAR alfa/genética , Co-Represor 1 de Receptor Nuclear/genética , Humanos , Fosforilación , Transducción de Señal

RESUMEN

Mycobacterium tuberculosis (Mtb) defends host-mediated killing by repressing the autophagolysosome machinery. For the first time, we report NCoR1 co-repressor as a crucial host factor, controlling Mtb growth in myeloid cells by regulating both autophagosome maturation and lysosome biogenesis. We found that the dynamic expression of NCoR1 is compromised in human peripheral blood mononuclear cells (PBMCs) during active Mtb infection, which is rescued upon prolonged anti-mycobacterial therapy. In addition, a loss of function in myeloid-specific NCoR1 considerably exacerbates the growth of M. tuberculosis in vitro in THP1 differentiated macrophages, ex vivo in bone marrow-derived macrophages (BMDMs), and in vivo in NCoR1MyeKO mice. We showed that NCoR1 depletion controls the AMPK-mTOR-TFEB signalling axis by fine-tuning cellular adenosine triphosphate (ATP) homeostasis, which in turn changes the expression of proteins involved in autophagy and lysosomal biogenesis. Moreover, we also showed that the treatment of NCoR1 depleted cells by Rapamycin, Antimycin-A, or Metformin rescued the TFEB activity and LC3 levels, resulting in enhanced Mtb clearance. Similarly, expressing NCoR1 exogenously rescued the AMPK-mTOR-TFEB signalling axis and Mtb killing. Overall, our data revealed a central role of NCoR1 in Mtb pathogenesis in myeloid cells.

Asunto(s)

Mycobacterium tuberculosis , Co-Represor 1 de Receptor Nuclear , Animales , Humanos , Ratones , Proteínas Quinasas Activadas por AMP , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice , Leucocitos Mononucleares , Células Mieloides , Serina-Treonina Quinasas TOR , Co-Represor 1 de Receptor Nuclear/metabolismo

RESUMEN

Recent studies suggest that chromosomal cohesin complex proteins are important in regulating hematopoiesis and may contribute to myeloid malignancies. To investigate the effects of perturbing the cohesin subunit protein RAD21 on normal hematopoiesis, we used conditional knockout (cKO) mouse models. While cohesin is vital for hematopoietic stem cell (HSC) function, Rad21 haploinsufficiency (Rad21Δ/+) led to distinct hematopoietic phenotypes. Our findings revealed that Rad21Δ/+ cells exhibited decreased hematopoietic reconstitution in competitive bone marrow transplantation assays. This reduction in peripheral blood chimerism was specifically observed in the lymphoid compartment, while the chimerism in the myeloid compartment remained unaffected. Rad21 haploinsufficiency also resulted in changes in the hematopoietic stem and progenitor cells (HSPC) and myeloid progenitor compartments, with a significant accumulation of granulocyte-macrophage progenitors in the bone marrow. We observed differential gene expression in Rad21Δ/+ LSK (Lin- Sca1-Kit+) cells, including genes required for HSPC function and differentiation, such as Setdb1, Hmga2, Ncor1, and Myb. In addition, we observed a notable decrease in the expression of genes related to the interferon response and a significant reduction in the expression of genes involved in the IL2-STAT5 signaling pathways. Our studies suggest that RAD21 protein and level of its post-translational modifications in the bone marrow cells may play a potential role in hematopoiesis. Overall, Rad21 haploinsufficiency impairs hematopoietic differentiation and increases HSC self-renewal.

Asunto(s)

Proteínas Cromosómicas no Histona , Trasplante de Células Madre Hematopoyéticas , Ratones , Animales , Diferenciación Celular , Proteínas Cromosómicas no Histona/genética , Proteínas Cromosómicas no Histona/metabolismo , Células Madre Hematopoyéticas/metabolismo , Hematopoyesis/genética , Ratones Endogámicos C57BL , Co-Represor 1 de Receptor Nuclear/metabolismo , Cohesinas

RESUMEN

BACKGROUND: The nuclear receptor corepressor 1 (NCOR1) plays an important role in the regulation of gene expression in immunometabolic conditions by connecting chromatin-modifying enzymes, coregulators and transcription factors. NCOR1 has been shown to be involved in cardiometabolic diseases. Recently, we demonstrated that the deletion of macrophage NCOR1 aggravates atherosclerosis by promoting CD36-triggered foam cell formation via PPARG derepression. PURPOSE: Since NCOR1 modulates the function of several key regulators involved in hepatic lipid and bile acid metabolism, we hypothesized that its deletion in hepatocytes alters lipid metabolism and atherogenesis. METHODS: To test this hypothesis, we generated hepatocyte-specific Ncor1 knockout mice on a Ldlr-/- background. Besides assessing the progression of the disease in thoracoabdominal aortae en face, we analyzed hepatic cholesterol and bile acid metabolism at expression and functional levels. RESULTS: Our data demonstrate that liver-specific Ncor1 knockout mice on an atherosclerosis-prone background develop less atherosclerotic lesions than controls. Interestingly, under chow diet, plasma cholesterol levels of liver-specific Ncor1 knockout mice were slightly higher compared to control, but strongly reduced compared to control mice after feeding them an atherogenic diet for 12 weeks. Moreover, the hepatic cholesterol content was decreased in liver-specific Ncor1 knockout compared to control mice. Our mechanistic data revealed that NCOR1 reprograms the synthesis of bile acids towards the alternative pathway, which in turn reduce bile hydrophobicity and enhances fecal cholesterol excretion. CONCLUSIONS: Our data suggest that hepatic Ncor1 deletion in mice decreases atherosclerosis development by reprograming bile acid metabolism and enhancing fecal cholesterol excretion.

Asunto(s)

Aterosclerosis , Esteroles , Ratones , Animales , Esteroles/metabolismo , Hígado/metabolismo , Colesterol , Aterosclerosis/genética , Aterosclerosis/prevención & control , Aterosclerosis/metabolismo , Ratones Noqueados , Ácidos y Sales Biliares/metabolismo , Metabolismo de los Lípidos , Ratones Endogámicos C57BL , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 1 de Receptor Nuclear/metabolismo

RESUMEN

Placental development relies on coordinated cell fate decisions governed by signalling inputs. However, little is known about how signalling cues are transformed into repressive mechanisms triggering lineage-specific transcriptional signatures. Here, we demonstrate that upon inhibition of the Fgf/Erk pathway in mouse trophoblast stem cells (TSCs), the Ets2 repressor factor (Erf) interacts with the Nuclear Receptor Co-Repressor Complex 1 and 2 (NCoR1/2) and recruits it to key trophoblast genes. Genetic ablation of Erf or Tbl1x (a component of the NCoR1/2 complex) abrogates the Erf/NCoR1/2 interaction. This leads to mis-expression of Erf/NCoR1/2 target genes, resulting in a TSC differentiation defect. Mechanistically, Erf regulates expression of these genes by recruiting the NCoR1/2 complex and decommissioning their H3K27ac-dependent enhancers. Our findings uncover how the Fgf/Erf/NCoR1/2 repressive axis governs cell fate and placental development, providing a paradigm for Fgf-mediated transcriptional control.

Asunto(s)

Factor 2 de Crecimiento de Fibroblastos , Trofoblastos , Ratones , Animales , Femenino , Embarazo , Placenta , Diferenciación Celular/fisiología , Regulación de la Expresión Génica , Co-Represor 1 de Receptor Nuclear , Co-Represor 2 de Receptor Nuclear

RESUMEN

Mitochondria are organelles known primarily for generating ATP via the oxidative phosphorylation process. Environmental signals are sensed by whole organisms or cells and markedly affect this process, leading to alterations in gene transcription and, consequently, changes in mitochondrial function and biogenesis. The expression of mitochondrial genes is finely regulated by nuclear transcription factors, including nuclear receptors and their coregulators. Among the best-known coregulators is the nuclear receptor corepressor 1 (NCoR1). Muscle-specific knockout of NCoR1 in mice induces an oxidative phenotype, improving glucose and fatty acid metabolism. However, the mechanism by which NCoR1 is regulated remains elusive. In this work, we identified the poly(A)-binding protein 4 (PABPC4) as a new NCoR1 interactor. Unexpectedly, we found that silencing of PABPC4 induced an oxidative phenotype in both C2C12 and MEF cells, as indicated by increased oxygen consumption, mitochondria content, and reduced lactate production. Mechanistically, we demonstrated that PABPC4 silencing increased the ubiquitination and consequent degradation of NCoR1, leading to the derepression of PPAR-regulated genes. As a consequence, cells with PABPC4 silencing had a greater capacity to metabolize lipids, reduced intracellular lipid droplets, and reduced cell death. Interestingly, in conditions known to induce mitochondrial function and biogenesis, both mRNA expression and PABPC4 protein content were markedly reduced. Our study, therefore, suggests that the lowering of PABPC4 expression may represent an adaptive event required to induce mitochondrial activity in response to metabolic stress in skeletal muscle cells. As such, the NCoR1-PABPC4 interface might be a new road to the treatment of metabolic diseases.

Asunto(s)

Receptores Citoplasmáticos y Nucleares , Factores de Transcripción , Animales , Ratones , Proteínas Co-Represoras/metabolismo , Co-Represor 1 de Receptor Nuclear/genética , Co-Represor 1 de Receptor Nuclear/metabolismo , Fosforilación Oxidativa , Receptores Citoplasmáticos y Nucleares/metabolismo , Estrés Fisiológico , Factores de Transcripción/metabolismo

RESUMEN

Phenotypic modulation of vascular smooth muscle cells (VSMCs) plays critical roles in the pathogenesis of aortic aneurysm (AA). The function of nuclear receptor corepressor1 (NCOR1) in regulation of VSMC phenotype and AA is unclear. Herein, using smooth muscle NCOR1 knockout mice, we demonstrated that smooth muscle NCOR1 deficiency decreased both mRNA and protein levels of contractile genes, impaired stress fibers formation and RhoA pathway activation, reduced synthesis of elastin and collagens, and induced the expression and activity of MMPs, manifesting a switch from contractile to degradative phenotype of VSMCs. NCOR1 modulated VSMC phenotype through 3 different mechanisms. First, NCOR1 deficiency increased acetylated FOXO3a to inhibit the expression of Myocd, which downregulated contractile genes. Second, deletion of NCOR1 derepressed NFAT5 to induce the expression of Rgs1, thus impeding RhoA activation. Third, NCOR1 deficiency increased the expression of Mmp12 and Mmp13 by derepressing ATF3. Finally, a mouse model combined apoE knockout mice with angiotensin II was used to study the role of smooth muscle NCOR1 in the development of AA. The results showed that smooth muscle NCOR1 deficiency increased the incidence of aortic aneurysms and exacerbated medial degeneration in angiotensin II-induced AA mouse model. Collectively, our data illustrated that NCOR1 interacts with FOXO3a, NFAT5, and ATF3 to maintain contractile phenotype of VSMCs and suppress AA development. Manipulation of smooth muscle NCOR1 may be a potential approach for AA treatment.

Asunto(s)

Aneurisma de la Aorta , Músculo Liso Vascular , Ratones , Animales , Músculo Liso Vascular/metabolismo , Angiotensina II/metabolismo , Aneurisma de la Aorta/metabolismo , Aneurisma de la Aorta/patología , Ratones Noqueados , Fenotipo , Ratones Noqueados para ApoE , Homeostasis , Células Cultivadas , Co-Represor 1 de Receptor Nuclear/metabolismo