RESUMO
Cytoplasmic dynein is an important intracellular motor protein that plays an important role in neuronal growth, axonal polarity formation, dendritic differentiation, and dendritic spine development among others. The intermediate chain of dynein, encoded by Dync1i1, plays a vital role in the dynein complex. Therefore, we assessed the behavioral and related neuronal activities in mice with dync1i1 gene knockout. Neuronal activities in primary somatosensory cortex were recorded by in vivo electrophysiology and manipulated by optogenetic and chemogenetics. Nociception of mechanical, thermal, and cold pain in Dync1i1-/- mice were impaired. The activities of parvalbumin (PV) interneurons and gamma oscillation in primary somatosensory were also impaired when exposed to mechanical nociceptive stimulation. This neuronal dysfunction was rescued by optogenetic activation of PV neurons in Dync1i1-/- mice, and mimicked by suppressing PV neurons using chemogenetics in WT mice. Impaired pain sensations in Dync1i1-/- mice were correlated with impaired gamma oscillations due to a loss of interneurons, especially the PV type. This genotype-driven approach revealed an association between impaired pain sensation and cytoplasmic dynein complex.
Assuntos
Parvalbuminas , Córtex Somatossensorial , Camundongos , Animais , Parvalbuminas/metabolismo , Córtex Somatossensorial/metabolismo , Dineínas do Citoplasma/metabolismo , Dineínas/metabolismo , Interneurônios/metabolismo , Limiar da DorRESUMO
The Golgi apparatus is vital for protein modification and molecular trafficking. It is essential for nerve development and activity, and damage thereof is implicated in many neurological diseases. Primary familial brain calcification (PFBC) is a rare inherited neurodegenerative disease characterized by multiple brain calcifications. SLC20A2, which encodes the inorganic phosphate transporter 2 (PiT-2) protein, is the main pathogenic gene in PFBC. The PiT-2 protein is a sodium-dependent phosphate type III transporter, and dysfunction leads to a deficit in the cellular intake of inorganic phosphate (Pi) and calcium deposits. Whether the impaired Golgi apparatus is involved in the PFBC procession requires elucidation. In this study, we constructed induced pluripotent stem cells (iPSCs) derived from two PFBC patients with different SLC20A2 gene mutations (c.613G > A or del exon10) and two healthy volunteers as dependable cell models for research on pathogenic mechanism. To study the mechanism, we differentiated iPSCs into neurons and astrocytes in vitro. Our study found disruptive Golgi structure and damaged autophagy in PFBC neurons with increased activity of mTOR. We also found damaged mitochondria and increased apoptosis in the PFBC dopaminergic neurons and astrocytes. In this study, we prove that dysfunctional PiT-2 leads to an imbalance of cellular Pi, which may disrupt the Golgi apparatus with impaired autophagy, mitochondria and apoptosis in PFBC. Our study provides a new avenue for understanding nerve damage and pathogenic mechanism in brain calcifications.
Assuntos
Calcinose , Doenças Neurodegenerativas , Humanos , Doenças Neurodegenerativas/metabolismo , Proteínas de Transporte de Fosfato/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo III/metabolismo , Fosfatos/metabolismo , Calcinose/metabolismo , Complexo de Golgi/metabolismo , Mutação , Encéfalo/metabolismoRESUMO
OBJECTIVE: Bariatric surgery (BS) is considered one of the most effective treatments for obese individuals with Obstructive Sleep Apnea (OSA). However, otolaryngologists have raised concerns about the structural alterations caused by BS on the upper respiratory tract, especially, on the pharyngeal cavity. METHODS: In this study, we recruited 42 individuals who underwent BS at our hospital. They were divided into two groups based on apnea-hypopnea index (AHI): mild group (5 ≤ AHI < 15) and moderate-severe group (AHI ≥ 15). The participants were followed up for 12 months and several indicators, including body mass index (BMI), polysomnography (PSG), and acoustic pharyngometry (APh), were assessed repeatedly before surgery and at 3, 6, and 12 months (m) after surgery. RESULTS: Participants exhibited significant decreases in BMI (F = 128.1, P = 0.001) and total weight loss (F = 176.7, P < 0.001) after BS. The AHI value among obese patients with mild OSA decreased significantly within three months after surgery (0 day vs. 3 months, P < 0.01), and decreased significantly more than 12 months with moderate-to-severe patients (0 day vs. 3 months, 3 months vs. 6 months, 6 months vs. 12 months, P < 0.01). The therapeutic effect of OSA of the mild group was significantly better compared with that of the moderate-severe group at 6 months (mean rank = 28.13 vs. 14.21, P < 0.001) and 12 m (mean rank = 26.75 vs. 15.52, P = 0.001). The APh results revealed that the pharyngeal volume of the two groups increased significantly between 0 day and 6 months after surgery (P < 0.01). The oropharyngeal junction (OPJ) area and the glottal area were increased significantly between 0 day and 6 m after surgery (P < 0.01). CONCLUSION: BS can relieve apnea and OSA symptoms among obese patients with OSA, especially in the early postoperative period. Moreover, OSA severity was closely associated with OPJ and glottal areas, rather than pharyngeal cavity volume.
Assuntos
Cirurgia Bariátrica , Apneia Obstrutiva do Sono , Humanos , Obesidade/complicações , Obesidade/cirurgia , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/cirurgia , Apneia Obstrutiva do Sono/diagnóstico , Cirurgia Bariátrica/efeitos adversos , Faringe/cirurgia , Período Pós-OperatórioRESUMO
BACKGROUND: Outcomes of gastroesophageal reflux disease (GERD) using Toupet fundoplication (TF) and Stretta radiofrequency (SRF) have not been compared and this study was conducted to compare therapeutic efficacy of the two methods. METHODS: This retrospective study analyzed a total of 230 patients undergoing TF or SRF at our hospital. Baseline data, reflux symptoms, the DeMeester scores, lower esophageal sphincter (LES) pressure and adverse events were compared over 1 year period. RESULTS: A total of 226 patients were included in the study. The time and frequency of reflux and percentage of reflux time before and 12 months after therapy were not significantly different. There were significantly interactions between the therapy method and follow-up time on the DeMeester score and LES pressure. Twelve months post therapy, the DeMeester score was significantly higher in SRF than in TF group, while the LES pressure was lower. At 12 months after therapy, multivariate Cox proportional regression analysis showed that reflux frequency, the DeMeester score and LES pressure were risk factors for poor prognosis in TF group, while reflux frequency and the DeMeester score, and LES pressure were risk factors for poor prognosis in SFR group. CONCLUSIONS: Compared with TF, SFR can significantly improve the esophageal pH and pressure in GERD patients without increasing the risk of poor prognosis.
Assuntos
Fundoplicatura/estatística & dados numéricos , Refluxo Gastroesofágico/terapia , Terapia por Radiofrequência/estatística & dados numéricos , Índice de Gravidade de Doença , Esfíncter Esofágico Inferior/fisiopatologia , Monitoramento do pH Esofágico , Feminino , Fundoplicatura/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Pressão , Prognóstico , Modelos de Riscos Proporcionais , Terapia por Radiofrequência/métodos , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Mitochondrial membrane potential (MMP) plays a crucial role in the function of cells and organelles, involving various cellular physiological processes, including energy production, formation of reactive oxygen species (ROS), unfolded protein stress, and cell survival. Currently, there is a lack of genetically encoded fluorescence indicators (GEVIs) for MMP. In our screening of various GEVIs for their potential monitoring MMP, the Accelerated Sensor of Action Potentials (ASAP) demonstrated optimal performance in targeting mitochondria and sensitivity to depolarization in multiple cell types. However, mitochondrial ASAPs also displayed sensitivity to ROS in cardiomyocytes. Therefore, two ASAP mutants resistant to ROS were generated. A double mutant ASAP3-ST exhibited the highest voltage sensitivity but weaker fluorescence. Overall, four GEVIs capable of targeting mitochondria were obtained and named mitochondrial potential indicators 1-4 (MPI-1-4). In vivo, fiber photometry experiments utilizing MPI-2 revealed a mitochondrial depolarization during isoflurane-induced narcosis in the M2 cortex.
RESUMO
Parkinson's disease (PD) is a mitochondria-related neurodegenerative disease characterized by locomotor deficits and loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). Majority of PD research primarily focused on neuronal dysfunction, while the roles of astrocytes and their mitochondria remain largely unexplored. To bridge the gap and investigate the roles of astrocytic mitochondria in PD progression, we constructed a specialized optogenetic tool, mitochondrial-targeted anion channelrhodopsin, to manipulate mitochondrial membrane potential in astrocytes. Utilizing this tool, the depolarization of astrocytic mitochondria within the SNc in vivo led to the accumulation of γ-aminobutyric acid (GABA) and glutamate in SNc, subsequently resulting in excitatory/inhibitory imbalance and locomotor deficits. Consequently, in vivo calcium imaging and interventions of neurotransmitter antagonists demonstrated that GABA accumulation mediated movement deficits of mice. Furthermore, 1 h/day intermittent astrocytic mitochondrial depolarization for 2 weeks triggered spontaneous locomotor dysfunction, α-synuclein aggregation, and the loss of DA neurons, suggesting that astrocytic mitochondrial depolarization was sufficient to induce a PD-like phenotype. In summary, our findings suggest the maintenance of proper astrocytic mitochondrial function and the reinstatement of a balanced neurotransmitter profile may provide a new angle for mitigating neuronal dysfunction during the initial phases of PD.
RESUMO
Pluripotent stem cells were generated through the electroporation of episomal plasmids, containing crucial reprogramming factors, into skin fibroblasts extracted from a female Alzheimer's patient harboring the PSEN1 709 T > C (p.Phe237Leu) heterozygous mutation. The pluripotent stem cells exhibit a normal karyotype and express pivotal stem cell markers including TRA-1-60, Nanog, SOX2, and OCT4. Furthermore, their capacity to differentiate into the three germ layers in in vivo teratoma experiments has been substantiated. The pluripotent stem cell line can serve as a cellular model for Alzheimer's disease, offering significant value in elucidating the pathogenesis and therapeutic strategies of the disease.
Assuntos
Doença de Alzheimer , Heterozigoto , Células-Tronco Pluripotentes Induzidas , Mutação , Presenilina-1 , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Feminino , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Presenilina-1/genética , Linhagem Celular , Diferenciação Celular , Fibroblastos/metabolismo , AnimaisRESUMO
The study is designed to explore the regulatory network that MALAT1 competitively binds with miR-188-5p to up-regulate PSMD10 to facilitate cholangiocarcinoma cell migration and invasion and suppress apoptosis. qRT-PCR and fluorescence in situ hybridization (FISH) were used to examine the expression and positive signal of MALAT1 and miR-188-5p in cholangiocarcinoma tissues and HIBEC, HCCC-9810, RBE, and QBC939 cells. Western blot, qRT-PCR, and immunohistochemistry were selected to detect PSMD10 expression in cholangiocarcinoma tissues and cell lines. Dual luciferase reporter gene assay was adopted to verify that miR-188-5p targeted MALAT1 and PSMD10. qRT-PCR, pull down, and western blot were used to examine the regulation of MALAT1-miR-188-5p-PSMD10 axis. Transwell, wound healing assay, and Tunel cell apoptosis were adopted to respectively detect the regulatory abilities of MALAT1-miR-188-5p-PSMD10 axis on cell invasion, migration, and apoptosis. Western blot was used to detect the regulation mechanism of MALAT1 on Bax, Bcl-2, and caspase-3 proteins. Nude mice subcutaneous xenograft model of cholangiocarcinoma was established to examine the impacts of MALAT1 on subcutaneous tumor growth. Immunohistochemistry was adopted to examine the positive indicator of Ki67 antibodies and SMD10 antibodies in each group. MALAT1 and PSMD10 were highly expressed in cholangiocarcinoma tissues and cell lines, while miR-188-5p was lowly expressed. MALAT1 could competitively bind to miR-188-5p, and miR-188-5p could negatively regulate PSMD10. MALAT1, In-miR-188-5p, and PSMD10 could facilitate cell invasion and migration and inhibit apoptosis, while siMALAT1, miR-188-5p, and siPSMD10 produced an opposite result. MALAT1-miR-188-5p-PSMD10 axis could promote RBE cell invasion and migration and inhibit apoptosis, whereas siMALAT1-In-miR-188-5p-siPSMD10 axis showed an opposite result. On the other hand, it was verified that up-regulation/down-regulation of MALAT1 can inhibit/promote Bax and caspase-3 proteins and promote/inhibit the expression of Bcl-2 protein. MALAT1 could facilitate subcutaneous tumor growth and enhance cell proliferation and positive signal of PSMD10, while miR-188-5p worked in an opposite direction. MALAT1 competitively binds to miR-188-5p to up-regulate mRNA translation and protein expression of PSMD10, thereby facilitating cholangiocarcinoma cell invasion and migration and inhibiting its apoptosis. However, interfering MALAT1-miR-188-5p-PSMD10 axis could inhibit the occurrence and development of cholangiocarcinoma.
Assuntos
Colangiocarcinoma , MicroRNAs , RNA Longo não Codificante , Animais , Humanos , Camundongos , Apoptose/genética , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Colangiocarcinoma/genética , Regulação Neoplásica da Expressão Gênica , Hibridização in Situ Fluorescente , Camundongos Nus , MicroRNAs/genética , MicroRNAs/metabolismo , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
The temperature of a living cell is a crucial parameter for cellular events, such as cell division, gene expressions, enzyme activities and metabolism. We previously developed a quantifiable mitochondrial thermometry 1.0 based on rhodamine B methyl ester (RhB-ME) and rhodamine 800 (Rh800), and the theory for mitochondrial thermogenesis. Given that the synthesized RhB-ME is not readily available, thus, a convenient mitochondrial thermometry 2.0 based on tetra-methyl rhodamine methyl ester (TMRM) and Rh800 for the thermogenic study of brown adipocyte was further evolved. The fluorescence of TMRM is more sensitive (â¼1.4 times) to temperature than that of RhB-ME, then the TMRM-based mito-thermometry 2.0 was validated and used for the qualitatively dynamic profiles for mitochondrial thermogenic responses and mitochondrial membrane potential in living cells simultaneously. Furthermore, our results demonstrated that the heterogenous thermogenesis evoked by ß3 adrenoceptor agonist only used overall up to â¼46% of the thermogenic capacity evoked by CCCP stimulation. On the other hand, the results demonstrated that the maximum thermogenesis evoked by NE and oligomycin A used up to â¼79% of the thermogenic capacity, which suggested the maximum thermogenic capacity under physiological conditions by inhibiting the proton-ATPase function of the mitochondrial complex V, such as under the cold activation of sympathetic nerve and the co-release of sympathetic transmitters.
RESUMO
Hepatocellular carcinoma (HCC) is an angiogenesis-dependent tumor, and angiogenesis plays pivotal roles in progression and hematogenous metastasis. Upregulating NDRG2 expression could inhibit endothelial cell proliferation and tumor angiogenesis. However, the development of angiogenesis is a complicated and dynamic process, and the specific mechanisms that NDRG2 influences its progression are largely unknown. Conditioned media (CM) was collected from HCC cells. Cell viability, migration assay, tube formation, and western blot were used to evaluate the effect of NDRG2 on angiogenesis in HCC cells. ELISA assay was used to measure the level of VEGFA in CM. CM from NDRG2 knockdown cells significantly promoted HUVECs proliferation, migration, and tube formation compared with control cells. The level of VEGFA in CM was increased by NDRG2 knockdown relative to the control group. The expression of VEGFA, HIF-1α, and p-Akt was significantly increased in NDRG2 knockdown cells. CM from NDRG2 knockdown cells with VEGFA antibody failed to induce HUVEC proliferation, migration, and tube formation. YC-1 significantly inhibited the level of VEGFA in CM from NDRG2 knockdown cells. YC-1 also inhibited the expression of VEGFA and HIF-1α. Therefore, NDRG2 inhibition promoted the angiogenesis of HCC via VEGFA and may be used to be an anti-angiogenesis target.
RESUMO
PURPOSE: To determine whether sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) should be the optimal choice in patients stratified by diabetes duration and body mass index (BMI) level. METHODS: Classification tree analysis was performed to identify the influential factors for surgical procedure selection in real setting. Meta-analyses stratified by influential factors were conducted to compare the complete diabetes remission rates between SG and RYGB. The cost-effectiveness analysis was performed when results from meta-analysis remain uncertain. RESULTS: Among 3198 bariatric procedures in China, 824 (73%) SGs and 191 (17%) RYGBs were performed in patients with T2DM. Diabetes duration with a cutoff value of 5 years and BMI level with 35.5 kg/m2 were identified as the influential factors. For patients with diabetes duration > 5 years, RYGB showed a significant higher complete diabetes remission rate than SG at 1 year: 0.52 (95% confidence interval (CI): 0.46-0.58) versus 0.36 (95% CI: 0.30-0.42). For patients with diabetes duration ≤ 5 years and BMI ≥ 35.5 kg/m2, there was no significant difference between 2 procedures: 0.57 (95% CI: 0.43-0.71) for SG versus 0.66 (95% CI: 0.62-0.70) for RYGB. The cost-effectiveness ratios of SG and RYGB were 244.58 and 276.97 dollars per QALY, respectively. CONCLUSIONS: For patients with diabetes duration > 5 years, RYGB was the optimal choice with regard to achieving complete diabetes remission at 1 year after surgery. However, for patients with diabetes duration ≤ 5 years and BMI ≥ 35.5 kg/m2, SG appeared to provide a cost-effective choice.
Assuntos
Diabetes Mellitus Tipo 2 , Derivação Gástrica , Obesidade Mórbida , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/cirurgia , Gastrectomia , Humanos , Obesidade Mórbida/cirurgia , Sistema de Registros , Resultado do TratamentoAssuntos
Fístula Biliar/complicações , Colelitíase/cirurgia , Doenças do Ducto Colédoco/complicações , Duodenopatias/complicações , Fístula Intestinal/complicações , Idoso de 80 Anos ou mais , Ductos Biliares Intra-Hepáticos , Colelitíase/complicações , Endoscopia Gastrointestinal , Humanos , MasculinoRESUMO
Biosyntheses of proteins, nucleotides and fatty acids, are essential for the malignant proliferation and survival of cancer cells. Cumulating research findings show that amino acid restrictions are potential strategies for cancer interventions. Meanwhile, dietary strategies are popular among cancer patients. However, there is still lacking solid rationale to clarify what is the best strategy, why and how it is. Here, integrated analyses and comprehensive summaries for the abundances, signalling and functions of amino acids in proteomes, metabolism, immunity and food compositions, suggest that, intermittent dietary lysine restriction with normal maize as an intermittent staple food for days or weeks, might have the value and potential for cancer prevention or therapy. Moreover, dietary supplements were also discussed for cancer cachexia including dietary immunomodulatory.
RESUMO
Existing techniques have many limitations in the diagnosis and classification of ischemic stroke (IS). Considering this, we used metabolomics to screen for potential biomarkers of IS and its subtypes and to explore the underlying related pathophysiological mechanisms. Serum samples from 99 patients with acute ischemic stroke (AIS) [the AIS subtypes included 49 patients with large artery atherosclerosis (LAA) and 50 patients with small artery occlusion (SAO)] and 50 matched healthy controls (HCs) were analyzed by non-targeted metabolomics based on liquid chromatography-mass spectrometry. A multivariate statistical analysis was performed to identify potential biomarkers. There were 18 significantly different metabolites, such as oleic acid, linoleic acid, arachidonic acid, L-glutamine, L-arginine, and L-proline, between patients with AIS and HCs. These different metabolites are closely related to many metabolic pathways, such as fatty acid metabolism and amino acid metabolism. There were also differences in metabolic profiling between the LAA and SAO groups. There were eight different metabolites, including L-pipecolic acid, 1-Methylhistidine, PE, LysoPE, and LysoPC, which affected glycerophospholipid metabolism, glycosylphosphatidylinositol-anchor biosynthesis, histidine metabolism, and lysine degradation. Our study effectively identified the metabolic profiles of IS and its subtypes. The different metabolites between LAA and SAO may be potential biomarkers in the context of clinical diagnosis. These results highlight the potential of metabolomics to reveal new pathways for IS subtypes and provide a new avenue to explore the pathophysiological mechanisms underlying IS and its subtypes.
RESUMO
Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive memory loss along with neuropsychiatric symptoms and a decline in activities of daily life. Its main pathological features are cerebral atrophy, amyloid plaques, and neurofibrillary tangles in the brains of patients. There are various descriptive hypotheses regarding the causes of AD, including the cholinergic hypothesis, amyloid hypothesis, tau propagation hypothesis, mitochondrial cascade hypothesis, calcium homeostasis hypothesis, neurovascular hypothesis, inflammatory hypothesis, metal ion hypothesis, and lymphatic system hypothesis. However, the ultimate etiology of AD remains obscure. In this review, we discuss the main hypotheses of AD and related clinical trials. Wealthy puzzles and lessons have made it possible to develop explanatory theories and identify potential strategies for therapeutic interventions for AD. The combination of hypometabolism and autophagy deficiency is likely to be a causative factor for AD. We further propose that fluoxetine, a selective serotonin reuptake inhibitor, has the potential to treat AD.
RESUMO
[This corrects the article DOI: 10.1038/s41392-019-0063-8.].
RESUMO
Human liver cancers, including hepatocellular carcinomas and intra-hepatic cholangiocarcinomas, are often diagnosed late with poor prognosis. A better understanding of cancer initiation could provide potential preventive therapies and increase survival. Models for studying human liver cancer initiation are largely missing. Here, using directly reprogrammed human hepatocytes (hiHeps) and inactivation of p53 and RB, we established organoids possessing liver architecture and function. HiHep organoids were genetically engineered to model the initial alterations in human liver cancers. Bona fide hepatocellular carcinomas were developed by overexpressing c-Myc. Excessive mitochondrion-endoplasmic reticulum coupling induced by c-Myc facilitated hepatocellular carcinoma initiation and seemed to be a target of preventive treatment. Furthermore, through the analysis of human intra-hepatic cholangiocarcinoma-enriched mutations, we demonstrate that the RAS-induced lineage conversion from hepatocytes to intra-hepatic cholangiocarcinoma cells can be prevented by the combined inhibition of Notch and JAK-STAT. Together, hiHep organoids represent a system that can be genetically manipulated to model cancer initiation and identify potential preventive therapies.
Assuntos
Hepatócitos/citologia , Neoplasias Hepáticas/patologia , Fígado/patologia , Organoides/citologia , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Colangiocarcinoma/patologia , Modelos Animais de Doenças , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Hepáticas/genética , Camundongos , Proteína Supressora de Tumor p53/genéticaRESUMO
Based on the first law of thermodynamics and the thermal diffusion equation, the deduced theoretical model of mitochondrial thermogenesis satisfies the Laplace equation and is a special case of the thermal diffusion equation. The model settles the long-standing question of the ability to increase cellular temperature by endogenous thermogenesis and explains the thermogenic characteristics of brown adipocytes. The model and calculations also suggest that the number of free available protons is the major limiting factor for endogenous thermogenesis and its speed.
RESUMO
Temperature distributions inside a living cell reflect the thermodynamics and functions of cellular components. We used a newly-developed method of mitochondrial thermometry based on Rhodamine B methyl ester, which equilibrates as a thermosensitive mixture of nonfluorescent and fluorescent resonance forms. Prostaglandin E2 (PGE2) is released from hepatic non-parenchymal Kupffer cells and acts as an inflammatory factor to impact various functions of hepatocytes. The activity of PGE2 on energy mechanism of hepatocytes has not been fully elucidated and in particular, which PGE2 receptor mediates the functions has been elusive. We identified EP4 as the major receptor of PGE2 via our mitochondrion-thermometry approach and then substantiated this receptor's role in hepatic metabolism. We discovered that PGE2 is able to decrease intracellular temperature of hepatocytes, via increasing some lipogenic genes' expressions, hampering lipolysis and mitochondrial ß-oxidation, reducing intracellular ATP level and elevating cAMP level through EP4 receptor. The redox status of hepatocytes represented by FAD vs FAD + NADH ratio is influenced by PGE2 in an EP4 receptor-dependent manner. Collectively, these data demonstrate that PGE2 regulates metabolism of hepatocytes mainly through EP4 receptor.
Assuntos
Corantes/metabolismo , Dinoprostona/metabolismo , Hepatócitos/metabolismo , Mitocôndrias/metabolismo , Receptores de Prostaglandina E Subtipo EP4/metabolismo , Termometria , Trifosfato de Adenosina/metabolismo , Animais , AMP Cíclico/metabolismo , Citosol/metabolismo , Espaço Intracelular/metabolismo , Metabolismo dos Lipídeos , Camundongos Endogâmicos C57BL , Oxirredução , TemperaturaRESUMO
Obesity is a worldwide epidemic and results from excessive energy intake or inefficient energy expenditure. It is promising to utilize the thermogenic function of brown adipose tissue for obesity intervention. However, the mechanisms controlling the efficacy of norepinephrine-induced thermogenesis in brown adipocytes remain elusive. Here we demonstrate that norepinephrine (NE) induces low-efficacy thermogenesis, evoking both heterogeneous changes (ΔΨm and ΔpH) and homogenous responses, one of which is that NE stimulation causes large amounts of ATP consumption in brown adipocytes. We reveal that the proton-ATPase activity of mitochondrial complex V is a key factor that antagonizes proton leakage by UCP1 and determines the efficacy of NE-induced thermogenesis in brown adipocytes. Furthermore, to avoid unnecessary and undesired heat production, we reveal that ATP is a necessary sympathetic cotransmitter for the high efficacy and specificity of NE-induced thermogenesis in brown adipocytes as it increases intracellular calcium concentrations and upregulates the ATP synthase activity of complex V. Thus, we demonstrate the modulation mechanism of thermogenic efficacy in brown adipocytes. These findings imply new strategies to partially or fully utilize the thermogenic capacity of brown adipocytes to identify therapeutic targets for the treatment of obesity and diabetes.