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1.
Cardiovasc Diabetol ; 23(1): 331, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39252021

RESUMO

BACKGROUND: Visceral adipose tissue in individuals with obesity is an independent cardiovascular risk indicator. However, it remains unclear whether adipose tissue influences common cardiovascular diseases, such as atherosclerosis, through its secreted exosomes. METHODS: The exosomes secreted by adipose tissue from diet-induced obesity mice were isolated to examine their impact on the progression of atherosclerosis and the associated mechanism. Endothelial apoptosis and the proliferation and migration of vascular smooth muscle cells (VSMCs) within the atherosclerotic plaque were evaluated. Statistical significance was analyzed using GraphPad Prism 9.0 with appropriate statistical tests. RESULTS: We demonstrate that adipose tissue-derived exosomes (AT-EX) exacerbate atherosclerosis progression by promoting endothelial apoptosis, proliferation, and migration of VSMCs within the plaque in vivo. MicroRNA-132/212 (miR-132/212) was detected within AT-EX cargo. Mechanistically, miR-132/212-enriched AT-EX exacerbates palmitate acid-induced endothelial apoptosis via targeting G protein subunit alpha 12 and enhances platelet-derived growth factor type BB-induced VSMC proliferation and migration by targeting phosphatase and tensin homolog in vitro. Importantly, melatonin decreases exosomal miR-132/212 levels, thereby mitigating the pro-atherosclerotic impact of AT-EX. CONCLUSION: These data uncover the pathological mechanism by which adipose tissue-derived exosomes regulate the progression of atherosclerosis and identify miR-132/212 as potential diagnostic and therapeutic targets for atherosclerosis.


Assuntos
Apoptose , Aterosclerose , Movimento Celular , Proliferação de Células , Modelos Animais de Doenças , Progressão da Doença , Exossomos , Camundongos Endogâmicos C57BL , MicroRNAs , Músculo Liso Vascular , Miócitos de Músculo Liso , Placa Aterosclerótica , Animais , MicroRNAs/metabolismo , MicroRNAs/genética , Exossomos/metabolismo , Exossomos/patologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Aterosclerose/genética , Proliferação de Células/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Músculo Liso Vascular/patologia , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Masculino , Transdução de Sinais , Células Cultivadas , Obesidade/metabolismo , Obesidade/patologia , Camundongos Knockout para ApoE , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Células Endoteliais/efeitos dos fármacos , Doenças da Aorta/patologia , Doenças da Aorta/metabolismo , Doenças da Aorta/genética , Becaplermina/farmacologia , Becaplermina/metabolismo , Gordura Intra-Abdominal/metabolismo , Gordura Intra-Abdominal/patologia , Camundongos , Humanos
2.
Int J Mol Sci ; 24(11)2023 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-37298523

RESUMO

Cortisol is a potent human steroid hormone that plays key roles in the central nervous system, influencing processes such as brain neuronal synaptic plasticity and regulating the expression of emotional and behavioral responses. The relevance of cortisol stands out in the disease, as its dysregulation is associated with debilitating conditions such as Alzheimer's Disease, chronic stress, anxiety and depression. Among other brain regions, cortisol importantly influences the function of the hippocampus, a structure central for memory and emotional information processing. The mechanisms fine-tuning the different synaptic responses of the hippocampus to steroid hormone signaling remain, however, poorly understood. Using ex vivo electrophysiology and wild type (WT) and miR-132/miR-212 microRNAs knockout (miRNA-132/212-/-) mice, we examined the effects of corticosterone (the rodent's equivalent to cortisol in humans) on the synaptic properties of the dorsal and ventral hippocampus. In WT mice, corticosterone predominantly inhibited metaplasticity in the dorsal WT hippocampi, whereas it significantly dysregulated both synaptic transmission and metaplasticity at dorsal and ventral regions of miR-132/212-/- hippocampi. Western blotting further revealed significantly augmented levels of endogenous CREB and a significant CREB reduction in response to corticosterone only in miR-132/212-/- hippocampi. Sirt1 levels were also endogenously enhanced in the miR-132/212-/- hippocampi but unaltered by corticosterone, whereas the levels of phospo-MSK1 were only reduced by corticosterone in WT, not in miR-132/212-/- hippocampi. In behavioral studies using the elevated plus maze, miRNA-132/212-/- mice further showed reduced anxiety-like behavior. These observations propose miRNA-132/212 as potential region-selective regulators of the effects of steroid hormones on hippocampal functions, thus likely fine-tuning hippocampus-dependent memory and emotional processing.


Assuntos
Corticosterona , MicroRNAs , Camundongos , Humanos , Animais , Corticosterona/farmacologia , Corticosterona/metabolismo , Hidrocortisona/metabolismo , Hipocampo/metabolismo , MicroRNAs/metabolismo , Plasticidade Neuronal
3.
Cell Biol Int ; 45(11): 2201-2210, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34019714

RESUMO

Hepatocellular carcinoma (HCC) is regarded as one of the most common malignancies worldwide leading to cancer-related death. Long noncoding RNAs (lncRNAs) are a critical modulator affecting HCC progression. Whereas, the pathogenesis of lncRNA RBM5-AS1 in the development of HCC remains unclear. Quantitative RT-PCR or western blot assays were applied to detect the expression of genes and proteins, respectively. The proliferation and metastasis abilities were assessed using Cell counting kit-8 (CCK-8), EdU and transwell assays. RNA immunoprecipitation (RIP) experiment was employed to validate the molecular interactions. RBM5-AS1 is highly expressed in HCC tissues and cell lines, especially in Hep3B and HepG2 cells. RBM5-AS1 knockdown dramatically restrains cell proliferation, invasion and migration of HCC cells. Importantly, RBM5-AS1 acts as an epigenetic regulator to elevate the H3K27me3 level of miR-132/212 promoter regions via recruiting PRC2 (EZH2, SUZ12, EED), and eventually reducing miR-132/212 expressions. The recovery experiments demonstrated that downregulation of miR-132/212 markedly eliminate the antitumor effects mediated by RBM5-AS1 silencing in HCC cells. The data of this work illustrate that RBM5-AS1 acts as an epigenetic regulator to promote the HCC progression by repressing miR-132/212 expressions, which would provide a new insight for understanding the action mechanism of RBM5-AS1 in HCC development.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas de Ligação a DNA/genética , MicroRNAs/genética , Proteínas de Ligação a RNA/genética , Proteínas Supressoras de Tumor/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Proteínas de Ligação a DNA/metabolismo , Epigênese Genética/genética , Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/genética , Células Hep G2 , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , MicroRNAs/metabolismo , Invasividade Neoplásica/genética , RNA Antissenso/genética , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais/genética , Proteínas Supressoras de Tumor/metabolismo
4.
Addict Biol ; 26(2): e12905, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32293776

RESUMO

Micro-RNAs (miRNAs) are highly evolutionarily conserved short-length/noncoding RNA molecules that modulate a wide range of cellular functions in many cell types by regulating the expression of a variety of targeted genes. miRNAs have also recently emerged as key regulators of neuronal genes mediating the effects of psychostimulant drugs and memory-related neuroplasticity processes. Smoking is a predominant addictive behaviour associated with millions of deaths worldwide, and nicotine is a potent natural psychoactive agonist of cholinergic receptors, highly abundant in cigarettes. The influence of miRNAs modulation on cholinergic signalling in the nervous system remains however poorly explored. Using miRNA knockout mice and biochemical, electrophysiological and pharmacological approaches, we examined the effects of miR-132/212 gene disruption on the levels of hippocampal nicotinic acetylcholine receptors, total ERK and phosphorylated ERK (pERK) and MeCP2 protein levels, and studied the impact of nicotine stimulation on hippocampal synaptic transmission and synaptic depression and strengthening. miR-132/212 deletion significantly altered α7-nAChR and pERK protein levels, but not total ERK or MeCP2, and resulted in both exacerbated synaptic depression and virtually abolished memory-related synaptic strengthening upon nicotine stimulation. These observations reveal a functional miRNAs/nicotinergic signalling interplay critical for nicotinic-receptor expression and neuroplasticity in brain structures relevant for drug addiction and learning and memory functions.


Assuntos
Giro Denteado/efeitos dos fármacos , MicroRNAs/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Nicotina/farmacologia , Animais , MAP Quinases Reguladas por Sinal Extracelular/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Masculino , Proteína 2 de Ligação a Metil-CpG/efeitos dos fármacos , Camundongos , Camundongos Knockout , Receptores Nicotínicos/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos , eIF-2 Quinase/efeitos dos fármacos
5.
J Cell Mol Med ; 19(8): 1994-2005, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25945589

RESUMO

Arteriogenesis is a complicated process induced by increased local shear-and radial wall-stress, leading to an increase in arterial diameter. This process is enhanced by growth factors secreted by both inflammatory and endothelial cells in response to physical stress. Although therapeutic promotion of arteriogenesis is of great interest for ischaemic diseases, little is known about the modulation of the signalling cascades via microRNAs. We observed that miR-132/212 expression was significantly upregulated after occlusion of the femoral artery. miR-132/212 knockout (KO) mice display a slower perfusion recovery after hind-limb ischaemia compared to wildtype (WT) mice. Immunohistochemical analysis demonstrates a clear trend towards smaller collateral arteries in KO mice. Although Ex vivo aortic ring assays score similar number of branches in miR-132/212 KO mice compared to WT, it can be stimulated with exogenous miR-132, a dominant member of the miR-132/212 family. Moreover, in in vitro pericyte-endothelial co-culture cell assays, overexpression of miR-132 and mir-212 in endothelial cells results in enhanced vascularization, as shown by an increase in tubular structures and junctions. Our results suggested that miR-132/212 may exert their effects by enhancing the Ras-Mitogen-activated protein kinases MAPK signalling pathway through direct inhibition of Rasa1, and Spred1. The miR-132/212 cluster promotes arteriogenesis by modulating Ras-MAPK signalling via direct targeting of its inhibitors Rasa1 and Spred1.


Assuntos
Membro Posterior/irrigação sanguínea , Isquemia/genética , MicroRNAs/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Morfogênese , Proteínas ras/metabolismo , Animais , Técnicas de Silenciamento de Genes , Células HEK293 , Membro Posterior/efeitos dos fármacos , Membro Posterior/patologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Técnicas In Vitro , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Isquemia/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Morfogênese/efeitos dos fármacos , Neovascularização Fisiológica/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
6.
Front Neurosci ; 18: 1421680, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39170678

RESUMO

Huntington's disease (HD) is a rare genetic neurodegenerative disorder caused by an expansion of CAG repeats in the Huntingtin (HTT) gene. One hypothesis suggests that the mutant HTT gene contributes to HD neuropathology through transcriptional dysregulation involving microRNAs (miRNAs). In particular, the miR-132/212 cluster is strongly diminished in the HD brain. This study explores the effects of miR-132/212 deficiency specifically in adult HD zQ175 mice. The absence of miR-132/212 did not impact body weight, body temperature, or survival rates. Surprisingly, miR-132/212 loss seemed to alleviate, in part, the effects on endogenous Htt expression, HTT inclusions, and neuronal integrity in HD zQ175 mice. Additionally, miR-132/212 depletion led to age-dependent improvements in certain motor functions. Transcriptomic analysis revealed alterations in HD-related networks in WT- and HD zQ175-miR-132/212-deficient mice, including significant overlap in BDNF and Creb1 signaling pathways. Interestingly, however, a higher number of miR-132/212 gene targets was observed in HD zQ175 mice lacking the miR-132/212 cluster, especially in the striatum. These findings suggest a nuanced interplay between miR-132/212 expression and HD pathogenesis, providing potential insights into therapeutic interventions. Further investigation is needed to fully understand the underlying mechanisms and therapeutic potential of modulating miR-132/212 expression during HD progression.

7.
Cells ; 11(2)2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-35053378

RESUMO

Nicotine addiction develops predominantly during human adolescence through smoking. Self-administration experiments in rodents verify this biological preponderance to adolescence, suggesting evolutionary-conserved and age-defined mechanisms which influence the susceptibility to nicotine addiction. The hippocampus, a brain region linked to drug-related memory storage, undergoes major morpho-functional restructuring during adolescence and is strongly affected by nicotine stimulation. However, the signaling mechanisms shaping the effects of nicotine in young vs. adult brains remain unclear. MicroRNAs (miRNAs) emerged recently as modulators of brain neuroplasticity, learning and memory, and addiction. Nevertheless, the age-dependent interplay between miRNAs regulation and hippocampal nicotinergic signaling remains poorly explored. We here combined biophysical and pharmacological methods to examine the impact of miRNA-132/212 gene-deletion (miRNA-132/212-/-) and nicotine stimulation on synaptic functions in adolescent and mature adult mice at two hippocampal synaptic circuits: the medial perforant pathway (MPP) to dentate yrus (DG) synapses (MPP-DG) and CA3 Schaffer collaterals to CA1 synapses (CA3-CA1). Basal synaptic transmission and short-term (paired-pulse-induced) synaptic plasticity was unaltered in adolescent and adult miRNA-132/212-/- mice hippocampi, compared with wild-type controls. However, nicotine stimulation promoted CA3-CA1 synaptic potentiation in mature adult (not adolescent) wild-type and suppressed MPP-DG synaptic potentiation in miRNA-132/212-/- mice. Altered levels of CREB, Phospho-CREB, and acetylcholinesterase (AChE) expression were further detected in adult miRNA-132/212-/- mice hippocampi. These observations propose miRNAs as age-sensitive bimodal regulators of hippocampal nicotinergic signaling and, given the relevance of the hippocampus for drug-related memory storage, encourage further research on the influence of miRNAs 132 and 212 in nicotine addiction in the young and the adult brain.


Assuntos
Envelhecimento/genética , Hipocampo/fisiologia , MicroRNAs/metabolismo , Plasticidade Neuronal/genética , Nicotina/farmacologia , Acetilcolinesterase/metabolismo , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Giro Denteado/efeitos dos fármacos , Giro Denteado/fisiologia , Regulação da Expressão Gênica/efeitos dos fármacos , Potenciação de Longa Duração/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Plasticidade Neuronal/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Transmissão Sináptica/efeitos dos fármacos
8.
Front Cardiovasc Med ; 8: 592362, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33816571

RESUMO

Compromised cardiac function is a hallmark for heart failure, mostly appearing as decreased contractile capacity due to dysregulated calcium handling. Unfortunately, the underlying mechanism causing impaired calcium handling is still not fully understood. Previously the miR-132/212 family was identified as a regulator of cardiac function in the failing mouse heart, and pharmaceutically inhibition of miR-132 is beneficial for heart failure. In this study, we further investigated the molecular mechanisms of miR-132/212 in modulating cardiomyocyte contractility in the context of the pathological progression of heart failure. We found that upregulated miR-132/212 expressions in all examined hypertrophic heart failure mice models. The overexpression of miR-132/212 prolongs calcium decay in isolated neonatal rat cardiomyocytes, whereas cardiomyocytes isolated from miR-132/212 KO mice display enhanced contractility in comparison to wild type controls. In response to chronic pressure-overload, miR-132/212 KO mice exhibited a blunted deterioration of cardiac function. Using a combination of biochemical approaches and in vitro assays, we confirmed that miR-132/212 regulates SERCA2a by targeting the 3'-end untranslated region of SERCA2a. Additionally, we also confirmed PTEN as a direct target of miR-132/212 and potentially participates in the cardiac response to miR132/212. In end-stage heart failure patients, miR-132/212 is upregulated and correlates with reduced SERCA2a expression. The up-regulation of miR-132/212 in heart failure impairs cardiac contractile function by targeting SERCA2a, suggesting that pharmaceutical inhibition of miR-132/212 might be a promising therapeutic approach to promote cardiac function in heart failure patients.

9.
Biosci Rep ; 40(5)2020 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-32319512

RESUMO

Precartilaginous stem cells (PCSCs) are adult stem cells that can initiate chondrocytes and bone development. In the present study, we explored whether miR-132/212 was involved in the proliferation of PCSCs via Hedgehog signaling pathway. PCSCs were isolated and purified with the fibroblast growth factor receptor-3 (FGFR-3) antibody. Cell viability, DNA synthesis and apoptosis were measured using MTT, BrdU and flow cytometric analysis. The mRNA and protein expression were detected by real-time PCR and Western blot, respectively. The target gene for miR-132/212 was validated by luciferase reporter assay. Results showed that transfection with miR-132/212 mimic significantly increased cell viability and DNA synthesis, and inhibited apoptosis of PCSCs. By contrast, miR-132/212 inhibitor could suppress growth and promote apoptosis of PCSCs. Luciferase reporter assays indicated that transfection of miR-132/212 led to a marked reduction of luciferase activity, but had no effect on PTCH1 3'-UTR mutated fragment, suggesting that Patched1 (PTCH1) is a target of miR-132/212. Furthermore, treatment with miR-132/212 mimics obviously increased the protein expression of Indian hedgehog (Ihh) and parathyroid hormone related protein (PTHrP), which was decreased after treatment with Hedgehog signaling inhibitor, cyclopamine. We also found that inhibition of Ihh/PTHrP signaling by cyclopamine significantly suppressed growth and DNA synthesis, and induced apoptosis in PCSCs. These findings demonstrate that miR-132/212 promotes growth and inhibits apoptosis in PCSCs by regulating PTCH1-mediated Ihh/PTHrP pathway, suggesting that miR-132/212 cluster might serve as a novel target for bone diseases.


Assuntos
Células-Tronco Adultas/fisiologia , Proliferação de Células/genética , Condrócitos/fisiologia , MicroRNAs/metabolismo , Animais , Apoptose/efeitos dos fármacos , Cartilagem Articular/citologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/metabolismo , Família Multigênica , Proteína Relacionada ao Hormônio Paratireóideo/metabolismo , Receptor Patched-1/metabolismo , Cultura Primária de Células , Coelhos , Alcaloides de Veratrum/farmacologia
10.
Front Physiol ; 11: 590, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32612537

RESUMO

Background: Myocardial infarction (MI) is caused by occlusion of the coronary artery and induces ischemia in the myocardium and eventually a massive loss in cardiomyocytes. Studies have shown many factors or treatments that can affect the healing and remodeling of the heart upon infarction, leading to better cardiac performance and clinical outcome. Previously, miR-132/212 has been shown to play an important role in arteriogenesis in a mouse model of hindlimb ischemia and in the regulation of cardiac contractility in hypertrophic cardiomyopathy in mice. In this study, we explored the role of miR-132/212 during ischemia in a murine MI model. Methods and Results: miR-132/212 knockout mice show enhanced cardiac contractile function at baseline compared to wild-type controls, as assessed by echocardiography. One day after induction of MI by permanent occlusion, miR-132/212 knockout mice display similar levels of cardiac damage as wild-type controls, as demonstrated by infarction size quantification and LDH release, although a trend toward more cardiomyocyte cell death was observed in the knockout mice as shown by TUNEL staining. Four weeks after MI, miR-132/212 knockout mice show no differences in terms of cardiac function, expression of cardiac stress markers, and fibrotic remodeling, although vascularization was reduced. In line with these in vivo observation, overexpression of miR-132 or miR-212 in neonatal rat cardiomyocyte suppress hypoxia induced cardiomyocyte cell death. Conclusion: Although we previously observed a role in collateral formation and myocardial contractility, the absence of miR-132/212 did not affect the overall myocardial performance upon a permanent occlusion of the coronary artery. This suggests an interplay of different roles of this miR-132/212 before and during MI, including an inhibitory effect on cell death and angiogenesis, and a positive effect on cardiac contractility and autophagic response. Thus, spatial or tissue specific manipulation of this microRNA family may be essential to fully understand the roles and to develop interventions to reduce infarct size.

11.
Peptides ; 122: 170171, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31614165

RESUMO

The current study investigated the angiotensin-converting enzyme (ACE) inhibitory activity of 4 synthetic tripeptides. All the peptides showed enzyme inhibitory activity, especially two promising ones, TTP (Thea-Thea-Pro) and gAgAP (GABA-GABA-Pro), with IC50 values of 0.92 and 3.4 µmol/L, respectively. Enzyme inhibition kinetics determined by Lineweaver-Burk plots revealed that TTP and gAgAP were competitive inhibitors with Ki values of 0.87 and 3.12 µmol/L, respectively. Molecular docking experiments confirmed that the higher inhibitory potency of TTP and gAgAP might be attributed to the formation of several critical hydrogen bonds with the active site residues in ACE. We further demonstrated that TTP and gAgAP initiated a rapid and significant decrease in systolic blood pressure (SBP) in spontaneously hypertensive rats (SHRs). TTP treatment lowered SBP to the same extent as captopril, although the duration of anti-hypertensive effect was shorter in TTP group than that observed in captopril group. Moreover, the transcription levels of angiotensin II receptor type 1 (agtr1) and miR-132/-212 were downregulated in SHRs after administration of TTP and gAgAP. In particular, TTP treatment caused a comparable reduction of agtr1 levels compared to captopril treatment, while miR-132/212 expression was significantly decreased. These results showed that compound TTP might be served as a potential antihypertensive candidate.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Hipertensão/tratamento farmacológico , Peptídeos/farmacologia , Peptidil Dipeptidase A/genética , Sequência de Aminoácidos/genética , Inibidores da Enzima Conversora de Angiotensina/química , Animais , Pressão Sanguínea/efeitos dos fármacos , Humanos , Ligação de Hidrogênio/efeitos dos fármacos , Cinética , Peptídeos/química , Peptídeos/genética , Ratos , Ratos Endogâmicos SHR/genética
12.
J Neurol Neuromedicine ; 3(1): 21-25, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29682634

RESUMO

Daily rhythms in behavior and physiology are coordinated by an endogenous clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. This central pacemaker also relays day length information to allow for seasonal adaptation, a process for which melatonin signaling is essential. How the SCN encodes day length is not fully understood. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression by directing target mRNAs for degradation or translational repression. The miR-132/212 cluster plays a key role in facilitating neuronal plasticity, and miR-132 has been shown previously to modulate resetting of the central clock. A recent study from our group showed that miR-132/212 in mice is required for optimal adaptation to seasons and non-24-hour light/dark cycles through regulation of its target gene, methyl CpG-binding protein (MeCP2), in the SCN and dendritic spine density of SCN neurons. Furthermore, in the seasonal rodent Mesocricetus auratus (Syrian hamster), adaptation to short photoperiods is accompanied by structural plasticity in the SCN independently of melatonin signaling, thus further supporting a key role for SCN structural and, in turn, functional plasticity in the coding of day length. In this commentary, we discuss our recent findings in context of what is known about day length encoding by the SCN, and propose future directions.

13.
Cell Rep ; 19(3): 505-520, 2017 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-28423315

RESUMO

The central circadian pacemaker, the suprachiasmatic nucleus (SCN), encodes day length information by mechanisms that are not well understood. Here, we report that genetic ablation of miR-132/212 alters entrainment to different day lengths and non-24 hr day-night cycles, as well as photoperiodic regulation of Period2 expression in the SCN. SCN neurons from miR-132/212-deficient mice have significantly reduced dendritic spine density, along with altered methyl CpG-binding protein (MeCP2) rhythms. In Syrian hamsters, a model seasonal rodent, day length regulates spine density on SCN neurons in a melatonin-independent manner, as well as expression of miR-132, miR-212, and their direct target, MeCP2. Genetic disruption of Mecp2 fully restores the level of dendritic spines of miR-132/212-deficient SCN neurons. Our results reveal that, by regulating the dendritic structure of SCN neurons through a MeCP2-dependent mechanism, miR-132/212 affects the capacity of the SCN to encode seasonal time.


Assuntos
Adaptação Fisiológica/genética , Relógios Circadianos/genética , Dendritos/metabolismo , MicroRNAs/metabolismo , Estações do Ano , Adaptação Fisiológica/efeitos da radiação , Animais , Comportamento Animal , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Relógios Circadianos/efeitos da radiação , Dendritos/efeitos da radiação , Espinhas Dendríticas/metabolismo , Espinhas Dendríticas/efeitos da radiação , Feminino , Deleção de Genes , Regulação da Expressão Gênica/efeitos da radiação , Luz , Masculino , Mesocricetus , Proteína 2 de Ligação a Metil-CpG/genética , Proteína 2 de Ligação a Metil-CpG/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Neurônios/metabolismo , Fotoperíodo , Proteoma/metabolismo , Transdução de Sinais/efeitos da radiação , Núcleo Supraquiasmático/metabolismo , Núcleo Supraquiasmático/efeitos da radiação , Serina-Treonina Quinases TOR/metabolismo , Fatores de Tempo
14.
RNA Dis ; 3(2)2016.
Artigo em Inglês | MEDLINE | ID: mdl-27713923

RESUMO

The microRNA (miRNA) class of small (typically 22-24 nt) non-coding RNA affects a wide range of physiological processes in the mammalian central nervous system (CNS). By acting as potent regulators of mRNA translation and stability, miRNAs fine-tune the expression of a multitude of genes that play critical roles in complex cognitive processes, including learning and memory. Of note, within the CNS, miRNAs can be expressed in an inducible, and cell-type specific manner. Here, we provide a brief overview of the expression and functional effects of the miR-132/212 gene locus in forebrain circuits of the CNS, and then discuss a recent publication that explored the contributions of miR-132 and miR-212 to cognition and to transcriptome regulation. We also discuss mechanisms by which synaptic activity regulates miR-132/212 expression, how miR-132 and miR-212 affect neuronal plasticity, and how the dysregulation of these two miRNAs could contribute to the development of cognitive impairments.

15.
Artigo em Chinês | WPRIM | ID: wpr-910397

RESUMO

Objective:To validate the effect of TUT4 on the radiosensitivity of esophageal epithelial cells (HEEC) by regulating the uridylation of miR132/212 clusters.Methods:The expression of TUT4 in HEEC at 0, 6, 18, 24 and 48 h after 0, 2, 4, 6 and 8 Gy X-ray irradiation was detected by PCR. The HEEC cells were divided into four groups: NC group, shTUT4 group, 6 Gy group, and 6 Gy+ shTUT4 group. The effects of TUT4 on cell radiosensitivity, cell proliferation, cell cycle, mitochondrial damage, and oxygen free radical production were detected respectively. The effect of down-regulated TUT4 expression on miR132/212 uridylation was detected by RT-PCR, and the radiosensitivity of HEEC with overexpression of miR132/212 or miR132/212+ UUU was detected by clone formation and proliferation assay, respectively. Proliferation assay was performed to detect the proliferation of HEEC when TUT4 expression was down-regulated and miR132/212 or miR132/212+ UUU was overexpressed.Results:TUT4 expression increased after different doses of X-ray irradiation ( t=12.84, 62.06, 27.86, 32.43, P<0.05). Downregulation of TUT4 expression increased the radiosensitivity of HEEC ( t=13.2, 5.85, 7.31, P<0.05) with a SER D0of 1.41 and D0=0.79, Dq=1.61, SF2=0.47. Compared with 6 Gy group, cell proliferation in 6 Gy+ shTUT4 group was decreased ( t=7.12, 13.63, P<0.05), cells in S phase were increased ( t=11.98, P<0.05), mitochondrial damage was increased ( t=11.98, P<0.05), and ROS level was increased ( t=15.65, P<0.05). Down-regulation of TUT4 expression increased miR132/212 expression and decreased miR132/212+ UUU expression ( t=27.90, 60.99, P<0.05). Overexpression of miR132/212 increased the radiosensitivity of HEEC, and overexpression of miR132/212+ UUU decreased the radiosensitivity of HEEC, with SER D0 of 1.20 and 0.71, respectively. Cell proliferation of shTUT4 + miR132/212 group waslower than that of shTUT4 group( t=4.76, 7.65, P<0.05), and cell proliferation of shTUT4 + miR132/212+ UUU group was higher than that of shTUT4 ( t=7.22, P<0.05). Conclusions:X-ray irradiation increased the expression of TUT4 in HEEC, and the down-regulation of TUT4 reduced HEEC radiosensitivity and radiation damage, where the uridylation of miR132/212 was involved in.

16.
Int J Clin Exp Med ; 7(11): 4115-22, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25550921

RESUMO

OBJECTIVE: Lung cancer remains the leading cause of cancer-related death worldwide and microRNAs (miRNAs) play important roles in lung cancer progression. In this study, we investigate the effects of miR-132/212 cluster on the growth of subcutaneous xenografts of human lung cancer H1299 cells in nude mice, and further explore the underlying mechanisms. METHODS: Nude mice with subcutaneous transplantation tumor of human lung cancer H1299 cells were randomly divided into three groups: the sham group, the control vector group, and the microRNA-132/212 group. The control vector and microRNA-132/212 cluster plasmid was intratumoral injected respectively. Tumor volume was measured during the intervention process, with a tumor growth curve generated. Immunohistochemistry was performed to analyze the expression level of Ki-67, P21, CyclinD1 and CD31 in each group. RESULTS: The tumor volume of miR-132/212 group was significantly smaller than that of the control group at the terminal time point (P < 0.05). The expression levels of Ki-67, CyclinD1 and CD31 in the miR-132/212 group was significantly lower than the control group (P < 0.05), while the expression levels of P21 in the miR-132/212 group were significantly higher than the control group (P < 0.05). CONCLUSION: miR-132/212 cluster significantly inhibited the growth of subcutaneous xenografts of human lung cancer H1299 cells in nude mice. The inhibitory effect of miR-132/212 cluster in tumor growth may be mediated by upregulating the expression of P21 and downregulating the expression of CyclinD1, thereby inhibiting tumor tissue proliferation and angiogenesis and resulting in the inhibition of tumor growth.

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