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Pyruvate kinase M2 (PKM2) is a key glycolytic enzyme interacting with the inositol 1,4,5-trisphosphate receptor (IP3R). This interaction suppresses IP3R-mediated cytosolic [Ca2+] rises. As PKM2 exists in monomeric, dimeric and tetrameric forms displaying different properties including catalytic activity, we investigated the molecular determinants of PKM2 enabling its interaction with IP3Rs. Treatment of HeLa cells with TEPP-46, a compound stabilizing the tetrameric form of PKM2, increased both its catalytic activity and the suppression of IP3R-mediated Ca2+ signals. Consistently, in PKM2 knock-out HeLa cells, PKM2C424L, a tetrameric, highly active PKM2 mutant, but not inactive PKM2K270M or the less active PKM2K305Q, suppressed IP3R-mediated Ca2+ release. Surprisingly, however, in vitro assays did not reveal a direct interaction between purified PKM2 and either the purified Fragment 5 of IP3R1 (a.a. 1932-2216) or the therein located D5SD peptide (a.a. 2078-2098 of IP3R1), the presumed interaction sites of PKM2 on the IP3R. Moreover, on-nucleus patch clamp of heterologously expressed IP3R1 in DT40 cells devoid of endogenous IP3Rs did not reveal any functional effect of purified wild-type PKM2, mutant PKM2 or PKM1 proteins. These results indicate that an additional factor mediates the regulation of the IP3R by PKM2 in cellulo. Immunoprecipitation of GRP75 using HeLa cell lysates co-precipitated IP3R1, IP3R3 and PKM2. Moreover, the D5SD peptide not only disrupted PKM2:IP3R, but also PKM2:GRP75 and GRP75:IP3R interactions. Our data therefore support a model in which catalytically active, tetrameric PKM2 suppresses Ca2+ signaling via the IP3R through a multiprotein complex involving GRP75.
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Receptores de Inositol 1,4,5-Trifosfato , Proteínas de Membrana , Humanos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/genética , Células HeLa , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Piruvato Quinase/metabolismo , Piruvato Quinase/genética , Sinalização do Cálcio , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP70/genética , Cálcio/metabolismo , Ligação Proteica , Multimerização ProteicaRESUMO
There have been in the last three decades repeated publications indicating that the inositol 1,4,5-trisphosphate receptor (IP3R) is regulated not only by cytosolic Ca2+ but also by intraluminal Ca2+. Although most studies indicated that a decreasing intraluminal Ca2+ level led to an inhibition of the IP3R, a number of publications reported exactly the opposite effect, i.e. an inhibition of the IP3R by high intraluminal Ca2+ levels. Although intraluminal Ca2+-binding sites on the IP3Rs were reported, a regulatory role for them was not demonstrated. It is also well known that the IP3R is regulated by a vast array of associated proteins, but only relatively recently proteins were identified that can be linked to the regulation of the IP3R by intraluminal Ca2+. The first to be reported was annexin A1 that is proposed to associate with the second intraluminal loop of the IP3R at high intraluminal Ca2+ levels and to inhibit the IP3R. More recently, ERdj5/PDIA19 reductase was described to reduce an intraluminal disulfide bridge of IP3R1 only at low intraluminal Ca2+ levels and thereby to inhibit the IP3R. Annexin A1 and ERdj5/PDIA19 can therefore explain most of the experimental results on the regulation of the IP3R by intraluminal Ca2+. Further studies are needed to provide a fuller understanding of the regulation of the IP3R from the intraluminal side. These findings underscore the importance of the state of the endoplasmic reticulum in the control of IP3R activity.
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Anexina A1 , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Anexina A1/metabolismo , Sinalização do Cálcio , Sítios de Ligação , Oxirredução , Cálcio/metabolismoRESUMO
Abstract Background It is justified by the high population's morbidity and mortality rate, as well as the increasing present use of nanoparticles in this pathological context. Objectives To describe the main nanotechnology breakthroughs in the field of cardiovascular disease (CVD) and disseminate pertinent information in the literature. Methods This is a systematic review conducted between September and October 2021. The review was carried out through basic nature, following the initial script for the selective reading of articles in chronological order to collect relevant and consistent data related to the theme. Results It is evidenced the main advances of nanotechnology in the field of CVDs, namely, acute coronary syndromes (ACSs), heart failure (HF), and systemic arterial hypertension (SAH). Conclusion The importance of further and deeper studies in this area is emphasized, in order to make the already approved treatments feasible, so they can reach all publics at a low cost.
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Pyruvate kinase M (PKM) 2 was described to interact with the inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) and suppress its activity. To further investigate the physiological importance of the PKM2:IP3R interaction, we developed and characterized HeLa PKM2 knockout (KO) cells. In the HeLa PKM2 KO cells, the release of Ca2+ to the cytosol appears to be more sensitive to low agonist concentrations than in HeLa wild-type (WT) cells. However, upon an identical IP3-induced Ca2+ release, Ca2+ uptake in the mitochondria is decreased in HeLa PKM2 KO cells, which may be explained by the smaller number of contact sites between the ER and the mitochondria. Furthermore, in HeLa PKM2 KO cells, mitochondria are more numerous, though they are smaller and less branched and have a hyperpolarized membrane potential. TAT-D5SD, a cell-permeable peptide representing a sequence derived from IP3R1 that can disrupt the PKM2:IP3R interaction, induces Ca2+ release into the cytosol and Ca2+ uptake into mitochondria in both HeLa WT and PKM2 KO cells. Moreover, TAT-D5SD induced apoptosis in HeLa WT and PKM2 KO cells but not in HeLa cells completely devoid of IP3Rs. These results indicate that PKM2 separately regulates cytosolic and mitochondrial Ca2+ handling and that the cytotoxic effect of TAT-D5SD depends on IP3R activity but not on PKM2. However, the tyrosine kinase Lck, which also interacts with the D5SD sequence, is expressed neither in HeLa WT nor PKM2 KO cells, and we can also exclude a role for PKM1, which is upregulated in HeLa PKM2 KO cells, indicating that the TAT-D5SD peptide has a more complex mode of action than anticipated.
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Apoptose , Mitocôndrias , Humanos , Células HeLa , Receptores de Inositol 1,4,5-Trifosfato , Peptídeos , Proteínas de Ligação a Hormônio da TireoideRESUMO
Endoplasmic reticulum (ER)-mitochondria contact sites are crucial to allow Ca2+ flux between them and a plethora of proteins participate in tethering both organelles together. Inositol 1,4,5-trisphosphate receptors (IP3Rs) play a pivotal role at such contact sites, participating in both ER-mitochondria tethering and as Ca2+-transport system that delivers Ca2+ from the ER towards mitochondria. At the ER-mitochondria contact sites, the IP3Rs function as a multi-protein complex linked to the voltage-dependent anion channel 1 (VDAC1) in the outer mitochondrial membrane, via the chaperone glucose-regulated protein 75 (GRP75). This IP3R-GRP75-VDAC1 complex supports the efficient transfer of Ca2+ from the ER into the mitochondrial intermembrane space, from which the Ca2+ ions can reach the mitochondrial matrix through the mitochondrial calcium uniporter. Under physiological conditions, basal Ca2+ oscillations deliver Ca2+ to the mitochondrial matrix, thereby stimulating mitochondrial oxidative metabolism. However, when mitochondrial Ca2+ overload occurs, the increase in [Ca2+] will induce the opening of the mitochondrial permeability transition pore, thereby provoking cell death. The IP3R-GRP75-VDAC1 complex forms a hub for several other proteins that stabilize the complex and/or regulate the complex's ability to channel Ca2+ into the mitochondria. These proteins and their mechanisms of action are discussed in the present review with special attention for their role in pathological conditions and potential implication for therapeutic strategies.
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Retículo Endoplasmático , Mitocôndrias , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Mitocôndrias/metabolismo , Retículo Endoplasmático/metabolismo , Membranas Mitocondriais/metabolismo , Morte Celular , Cálcio/metabolismo , Sinalização do Cálcio/fisiologiaRESUMO
Anti-apoptotic BCL-2 targets and inhibits IP3 receptors (IP3Rs), thereby preventing apoptosis by limiting ER-mitochondrial Ca2+ flux. Recently, Dulloo et al. (2022), Nat. Comm. 13:1257[6] revealed a novel role for rhomboid pseudoproteases in ER stress-induced apoptosis by stripping BCL-2 from IP3Rs, thereby enabling pro-apoptotic Ca2+ signaling.
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Sinalização do Cálcio , Proteínas Proto-Oncogênicas c-bcl-2 , Apoptose , Cálcio/metabolismo , Morte Celular , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
Pyruvate kinase isoform M2 (PKM2) is a rate-limiting glycolytic enzyme that is widely expressed in embryonic tissues. The expression of PKM2 declines in some tissues following embryogenesis, while other pyruvate kinase isozymes are upregulated. However, PKM2 is highly expressed in cancer cells and is believed to play a role in supporting anabolic processes during tumour formation. In this study, PKM2 was identified as an inositol 1,4,5-trisphosphate receptor (IP3R)-interacting protein by mass spectrometry. The PKM2:IP3R interaction was further characterized by pull-down and co-immunoprecipitation assays, which showed that PKM2 interacted with all three IP3R isoforms. Moreover, fluorescence microscopy indicated that both IP3R and PKM2 localized at the endoplasmic reticulum. PKM2 binds to IP3R at a highly conserved 21-amino acid site (corresponding to amino acids 2078-2098 in mouse type 1 IP3R isoform). Synthetic peptides (denoted 'TAT-D5SD' and 'D5SD'), based on the amino acid sequence at this site, disrupted the PKM2:IP3R interaction and potentiated IP3R-mediated Ca2+ release both in intact cells (TAT-D5SD peptide) and in a unidirectional 45Ca2+ flux assay on permeabilized cells (D5SD peptide). The TAT-D5SD peptide did not affect the enzymatic activity of PKM2. Reducing PKM2 protein expression using siRNA increased IP3R-mediated Ca2+ signalling in intact cells without altering the ER Ca2+ content. These data identify PKM2 as an IP3R-interacting protein that inhibits intracellular Ca2+ signalling. The elevated expression of PKM2 in cancer cells is therefore not solely connected to its canonical role in glycolytic metabolism, rather PKM2 also has a novel non-canonical role in regulating intracellular signalling.
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Sinalização do Cálcio , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Piruvato Quinase/metabolismo , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Linhagem Celular , Citosol/metabolismo , Retículo Endoplasmático/metabolismo , Humanos , Receptores de Inositol 1,4,5-Trifosfato/química , Linfócitos/citologia , Linfócitos/metabolismo , Camundongos , Ligação Proteica , Domínios Proteicos , Isoformas de Proteínas/metabolismo , Piruvato Quinase/antagonistas & inibidores , Piruvato Quinase/genética , Interferência de RNA , RNA Interferente Pequeno/metabolismoRESUMO
The expression of the inositol 1,4,5-trisphosphate receptor type 3 (ITRP3) in hepatocytes is a common event in the pathogenesis of hepatocellular carcinoma (HCC), regardless of the type of underlying liver disease. However, it is not known whether ITPR3 expression in hepatocytes is involved in tumor maintenance. The aim of the present study was to determine whether there is an association between ITPR3 expression and clinical and morphological parameters using HCC samples obtained from liver explants from patients (n=53) with different etiologies of underlying chronic liver disease (CLD). ITPR3 expression, mitosis and apoptosis were analyzed in human liver samples by immunohistochemistry. Clinical and event-free survival data were combined to assess the relationship between ITPR3 and liver cancer growth in patients. RNA sequencing analysis was performed to identify apoptotic genes altered by ITPR3 expression in a liver tumor cell line. ITPR3 was highly expressed in HCC tumor cells relative to adjacent CLD tissue and healthy livers. There was an inverse correlation between ITPR3 expression and mitotic and apoptotic indices in HCC, suggesting that ITPR3 contributed to the maintenance of HCC by promoting resistance to apoptosis. This was confirmed by the upregulation of CTSB, CHOP and GADD45, genes involved in the apoptotic pathway in HCC. The expression of ITPR3 in the liver may be a promising prognostic marker of HCC.
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Introduction: This study assessed the knowledge and satisfaction of a nursing staff regarding peripherally inserted central catheter (PICC) care before and after a combined training strategy consisting of a video and hands-on practice.Methods: A cross-sectional and prospective study with data collection held at a public university hospital from March 2018 to May 2018 and in March 2019. Participants answered a pre-test about PICC lines, watched a video on PICC care and maintenance, attended hands-on sessions, and answered a post-test.Results: A total of 520 professionals participated in the study, of which 87.4% were from the nursing staff. The pre-test was answered by 211 individuals and the post-test questions were answered by 203 people. The satisfaction research showed 97% of satisfied respondents.Conclusions: Our results indicate that a change from the traditional training model to an active educational approach reached more participants, representing an innovative pedagogical tool in the training of critical and reflexive professionals.
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Recursos Audiovisuais , Ensino/educação , Cateterismo Periférico/enfermagem , Cuidados de Enfermagem/métodos , Capacitação de Recursos Humanos em Saúde , Dispositivos de Acesso VascularRESUMO
Objetivo: compreender as principais complicações ocasionadas pelo vírus SARS-CoV-2 no sistema cardíaco do público idoso. Métodos: trata-se de uma revisão sistemática da literatura de abordagem qualitativa e característica descritivo-exploratória realizada no ano de 2020. Resultados: as complicações cardíacas mais prevalentes na população idosa foram miocardite, arritmias, insuficiência cardíaca, infarto agudo, choque cardiogênico, lesão miocárdica aguda e parada cardiorrespiratória. O principal biomarcador cardíaco foi a troponina, apresentando elevação superior ao percentil 99°, evidenciando a necessidade de tratamento em Unidade de Terapia Intensiva. Considerações Finais: o aparecimento desse vírus causou grande prejuízo no campo da saúde, especialmente a população idosa, que apresenta risco elevado de óbito ao contrair essa doença. Destarte, é de extrema importância se ater a mensuração da troponina sérica no público alvo e realizar monitorização longitudinal, utilizando para tal a telecardiologia, uma vez que diminuem as chances de contaminação entre infectado e profissional de saúde
Objective: to understand the main complications of SARS-CoV-2 in the elderly cardiac system. Methods: systematic literature review conducted in 2020. Results: the most prevalent cardiac complications in the elderly population were myocarditis, arrhythmias, heart failure, acute infarction, cardiogenic shock, acute myocardial injury and cardiorespiratory arrest. The main cardiac biomarker was troponin, showing an elevation above the 99th percentile, evidencing the need for treatment in the Intensive Care Unit. Final Considerations: the appearance of this virus has caused great damage in the health field, especially the elderly population, who is at high risk of death when contracting this disease. Therefore, it is important to stick to the measurement of serum troponin in the target audience and perform longitudinal monitoring, using telecardiology for this purpose, since they reduce the chances of contamination between infected and health professionals
Objetivo: comprender las principales complicaciones del SARS-CoV-2 en el sistema cardíaco anciano. Métodos: revisión sistemática de la literatura realizada en 2020. Resultados: las complicaciones cardíacas más prevalentes en la población anciana fueron miocarditis, arritmias, insuficiencia cardíaca, infarto agudo, shock cardiogénico, lesión miocárdica aguda y parada cardiorrespiratoria. El principal biomarcador cardíaco fue la troponina, mostrando una elevación por encima del percentil 99, evidenciando la necesidad de tratamiento en la Unidad de Cuidados Intensivos. Consideraciones finales: la aparición de este virus ha provocado un gran daño en el campo de la salud, especialmente en la población anciana, que se encuentra en alto riesgo de muerte al contraer esta enfermedad. Por tanto, es importante ceñirse a la medición de troponina sérica en el público objetivo y realizar un seguimiento longitudinal, utilizando para ello la telecardiología, ya que reducen las posibilidades de contaminación entre los infectados y los profesionales sanitarios
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Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Troponina , Saúde do Idoso , COVID-19/complicações , Cardiopatias/etiologia , Equipe de Assistência ao Paciente , Choque Cardiogênico , Telecardiologia , Parada Cardíaca , Insuficiência Cardíaca , Unidades de Terapia Intensiva , MiocarditeRESUMO
Inside cells, the endoplasmic reticulum (ER) forms the largest Ca2+ store. Ca2+ is actively pumped by the SERCA pumps in the ER, where intraluminal Ca2+-binding proteins enable the accumulation of large amount of Ca2+. IP3 receptors and the ryanodine receptors mediate the release of Ca2+ in a controlled way, thereby evoking complex spatio-temporal signals in the cell. The steady state Ca2+ concentration in the ER of about 500 µM results from the balance between SERCA-mediated Ca2+ uptake and the passive leakage of Ca2+. The passive Ca2+ leak from the ER is often ignored, but can play an important physiological role, depending on the cellular context. Moreover, excessive Ca2+ leakage significantly lowers the amount of Ca2+ stored in the ER compared to normal conditions, thereby limiting the possibility to evoke Ca2+ signals and/or causing ER stress, leading to pathological consequences. The so-called Ca2+-leak channels responsible for Ca2+ leakage from the ER are however still not well understood, despite over 20 different proteins have been proposed to contribute to it. This review has the aim to critically evaluate the available evidence about the various channels potentially involved and to draw conclusions about their relative importance.
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Canais de Cálcio/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Sarcoplasmático/metabolismo , Cálcio/metabolismo , Cálcio/fisiologia , Sinalização do Cálcio/fisiologia , Humanos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Transdução de Sinais/fisiologiaRESUMO
Hepatic ischemia-reperfusion injury is seen in a variety of clinical conditions, including hepatic thrombosis, systemic hypotension, and liver transplantation. Calcium (Ca2+) signaling mediates several pathophysiological processes in the liver, but it is not known whether and how intracellular Ca2+ channels are involved in the hepatocellular events secondary to ischemia-reperfusion. Using an animal model of hepatic ischemia-reperfusion injury, we observed a progressive increase in expression of the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular Ca2+ channel that is not normally expressed in healthy hepatocytes. ITPR3 expression was upregulated, at least in part, by a combination of demethylation of the ITPR3 promoter region and the increased transcriptional activity of the nuclear factor of activated T-cells (NFAT). Additionally, expression of pro-inflammatory interleukins and necrotic surface area were less pronounced in livers of control animals compared to liver-specific ITPR3 KO mice subjected to hepatic damage. Corroborating these findings, ITPR3 expression and activation of NFAT were observed in hepatocytes of liver biopsies from patients who underwent liver ischemia caused by thrombosis after organ transplant. Together, these results are consistent with the idea that ITPR3 expression in hepatocytes plays a protective role during hepatic injury induced by ischemia-reperfusion.
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Hepatócitos/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Fígado/metabolismo , Fígado/patologia , Substâncias Protetoras/metabolismo , Traumatismo por Reperfusão/metabolismo , Animais , Sinalização do Cálcio , Desmetilação do DNA , Modelos Animais de Doenças , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Transcrição NFATC/metabolismo , Regiões Promotoras Genéticas/genéticaRESUMO
Yellow fever (YF) is a viral hemorrhagic fever that typically involves the liver. Brazil recently experienced its largest recorded YF outbreak, and the disease was fatal in more than a third of affected individuals, mostly because of acute liver failure. Affected individuals are generally treated only supportively, but during the recent Brazilian outbreak, selected patients were treated with liver transplant. We took advantage of this clinical experience to better characterize the clinical and pathological features of YF-induced liver failure and to examine the mechanism of hepatocellular injury in YF, to identify targets that would be amenable to therapeutic intervention in preventing progression to liver failure and death. Patients with YF liver failure rapidly developed massive transaminase elevations, with jaundice, coagulopathy, thrombocytopenia, and usually hepatic encephalopathy, along with pathological findings that included microvesicular steatosis and lytic necrosis. Hepatocytes began to express the type 3 isoform of the inositol trisphosphate receptor (ITPR3), an intracellular calcium (Ca2+) channel that is not normally expressed in hepatocytes. Experiments in an animal model, isolated hepatocytes, and liver-derived cell lines showed that this new expression of ITPR3 was associated with increased nuclear Ca2+ signaling and hepatocyte proliferation, and reduced steatosis and cell death induced by the YF virus. Conclusion: Yellow fever often induces liver failure characterized by massive hepatocellular damage plus steatosis. New expression of ITPR3 also occurs in YF-infected hepatocytes, which may represent an endogenous protective mechanism that could suggest approaches to treat affected individuals before they progress to liver failure, thereby decreasing the mortality of this disease in a way that does not rely on the costly and limited resource of liver transplantation.
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The liver is a complex organ that performs several functions to maintain homeostasis. These functions are modulated by calcium, a second messenger that regulates several intracellular events. In hepatocytes and cholangiocytes, which are the epithelial cell types in the liver, inositol 1,4,5-trisphosphate (InsP3) receptors (ITPR) are the only intracellular calcium release channels. Three isoforms of the ITPR have been described, named type 1, type 2 and type 3. These ITPR isoforms are differentially expressed in liver cells where they regulate distinct physiological functions. Changes in the expression level of these receptors correlate with several liver diseases and hepatic dysfunctions. In this review, we highlight how the expression level, modulation, and localization of ITPR isoforms in hepatocytes and cholangiocytes play a role in hepatic homeostasis and liver pathology.
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Ductos Biliares Intra-Hepáticos/metabolismo , Sinalização do Cálcio , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Hepatopatias/patologia , Fígado/metabolismo , Animais , Ductos Biliares Intra-Hepáticos/citologia , Cálcio/metabolismo , Modelos Animais de Doenças , Hepatócitos/metabolismo , Humanos , Fígado/citologia , Fígado/patologia , Isoformas de Proteínas/metabolismoRESUMO
BACKGROUND & OBJECTIVES: Hepatocellular carcinoma (HCC) is the second leading cause of cancer death worldwide. Several types of chronic liver disease predispose to HCC, and several different signalling pathways have been implicated in its pathogenesis, but no common molecular event has been identified. Ca2+ signalling regulates the proliferation of both normal hepatocytes and liver cancer cells, so we investigated the role of intracellular Ca2+ release channels in HCC. DESIGN: Expression analyses of the type 3 isoform of the inositol 1, 4, 5-trisphosphate receptor (ITPR3) in human liver samples, liver cancer cells and mouse liver were combined with an evaluation of DNA methylation profiles of ITPR3 promoter in HCC and characterisation of the effects of ITPR3 expression on cellular proliferation and apoptosis. The effects of de novo ITPR3 expression on hepatocyte calcium signalling and liver growth were evaluated in mice. RESULTS: ITPR3 was absent or expressed in low amounts in hepatocytes from normal liver, but was expressed in HCC specimens from three independent patient cohorts, regardless of the underlying cause of chronic liver disease, and its increased expression level was associated with poorer survival. The ITPR3 gene was heavily methylated in control liver specimens but was demethylated at multiple sites in specimens of patient with HCC. Administration of a demethylating agent in a mouse model resulted in ITPR3 expression in discrete areas of the liver, and Ca2+ signalling was enhanced in these regions. In addition, cell proliferation and liver regeneration were enhanced in the mouse model, and deletion of ITPR3 from human HCC cells enhanced apoptosis. CONCLUSIONS: These results provide evidence that de novo expression of ITPR3 typically occurs in HCC and may play a role in its pathogenesis.
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Carcinoma Hepatocelular/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Neoplasias Hepáticas/metabolismo , Adulto , Animais , Apoptose/fisiologia , Sinalização do Cálcio/fisiologia , Carcinogênese/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Proliferação de Células/fisiologia , Células Cultivadas , Metilação de DNA , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Hepatócitos/metabolismo , Humanos , Receptores de Inositol 1,4,5-Trifosfato/deficiência , Receptores de Inositol 1,4,5-Trifosfato/genética , Fígado/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Regeneração Hepática/fisiologia , Masculino , Camundongos Knockout , Pessoa de Meia-Idade , Análise de SobrevidaRESUMO
Alcoholic liver disease (ALD) is a highly prevalent spectrum of pathologies caused by alcohol overconsumption. Morbidity and mortality related to ALD are increasing worldwide, thereby demanding strategies for early diagnosis and detection of ALD predisposition. A potential candidate as a marker for ALD susceptibility is the transcription factor nuclear factor erythroid-related factor 2 (Nrf2), codified by the nuclear factor erythroid 2-related factor 2 gene (NFE2L2). Nrf2 regulates expression of proteins that protect against oxidative stress and inflammation caused by alcohol overconsumption. Here, we assessed genetic variants of NFE2L2 for association with ALD. Specimens from patients diagnosed with cirrhosis caused by ALD were genotyped for three NFE2L2 single nucleotide polymorphisms (SNP) (SNPs: rs35652124, rs4893819, and rs6721961). Hematoxylin & eosin and immunohistochemistry were performed to determine the inflammatory score and Nrf2 expression, respectively. SNPs rs4893819 and rs6721961 were not specifically associated with ALD, but analysis of SNP rs35652124 suggested that this polymorphism predisposes to ALD. Furthermore, SNP rs35652124 was associated with a lower level of Nrf2 expression. Moreover, liver samples from ALD patients with this polymorphism displayed more severe inflammatory activity. Together, these findings provide evidence that the SNP rs35652124 variation in the Nrf2-encoding gene NFE2L2 is a potential genetic marker for susceptibility to ALD.
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Predisposição Genética para Doença , Cirrose Hepática Alcoólica/genética , Fator 2 Relacionado a NF-E2/genética , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Adulto , Estudos de Casos e Controles , Etanol/farmacologia , Feminino , Expressão Gênica , Hepacivirus/crescimento & desenvolvimento , Hepacivirus/patogenicidade , Hepatite C/patologia , Hepatite C/virologia , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática Alcoólica/metabolismo , Cirrose Hepática Alcoólica/patologia , Cirrose Hepática Alcoólica/cirurgia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Estresse OxidativoRESUMO
Mitochondria and the endoplasmic reticulum (ER) have an intimate functional relationship due to tethering proteins that bring their membranes in close (~30 nm) apposition. One function of this interorganellar junction is to increase the efficiency of Ca2+ transfer into mitochondria, thus stimulating mitochondrial respiration. Here, we showed that the ER cation-permeant channel polycystin 2 (PC2) functions to reduce mitochondria-ER contacts. In cell culture models, PC2 knockdown led to a 50% increase in mitofusin 2 (MFN2) expression, an outer mitochondrial membrane GTPase. Live-cell super-resolution and electron microscopy analyses revealed enhanced MFN2-dependent tethering between the ER and mitochondria in PC2 knockdown cells. PC2 knockdown also led to increased ER-mediated mitochondrial Ca2+ signaling, bioenergetic activation, and mitochondrial density. Mutation or deletion of the gene encoding for PC2 results in autosomal dominant polycystic kidney disease (ADPKD), a condition characterized by numerous fluid-filled cysts. In cell culture models and mice with kidney-specific PC2 knockout, knockdown of MFN2 rescued defective mitochondrial Ca2+ transfer and diminished cell proliferation in kidney cysts. Consistent with these results, cyst-lining epithelial cells from human ADPKD kidneys had a twofold increase in mitochondria and MFN2 expression. Our data suggest that PC2 normally serves to limit key mitochondrial proteins at the ER-mitochondrial interface and acts as a checkpoint for mitochondrial biogenesis and bioenergetics. Loss of this regulation may contribute to the increased oxidative metabolism and aberrant cell proliferation typical of kidney cysts in ADPKD.
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Cálcio/metabolismo , Metabolismo Energético , GTP Fosfo-Hidrolases/metabolismo , Mitocôndrias/metabolismo , Transdução de Sinais , Canais de Cátion TRPP/metabolismo , Animais , Células Cultivadas , Retículo Endoplasmático/metabolismo , GTP Fosfo-Hidrolases/genética , Regulação da Expressão Gênica , Humanos , Células LLC-PK1 , Camundongos Knockout , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/metabolismo , Interferência de RNA , Suínos , Canais de Cátion TRPP/genéticaRESUMO
Background: Rheumatic carditis is a challenge for treatment and secondary prophylaxis, due to severe valve sequelae. Objective: To evaluate the cases of rheumatic carditis in patients under 18 years old treated with corticosteroids.Methods: An observational, longitudinal and retrospective study was carried out on the profile of patients, in the period of 2000-2015. We selected those who received corticosteroid therapy at immunosuppressive doses, for the treatment of carditis and were aged 5 to 18 years. Data were extracted from medical records. Calculations of: averages, standard deviations, medians and interquartile ranges, ratios and 95% confidence intervals were obtained. Chi-square and Wilcoxon tests were applied for comparisons. The level of significance was 5%. Results: Of the 93 cases, 93.53% developed moderate or severe carditis. Mitral regurgitation was detected in 100% of the sample. Pulse therapy was administered in 11.83%. Surgery was performed in 23.69% of patients: mitral, aortic and/or tricuspid valve repair or replacement. The evolution of the cases was favorable in 70.96%. There was a good response among those who received only clinical treatment and those who belonged to the surgical group. The comparison of the initial and posterior valve lesions to the corticoid use was statistically significant (p < 0.001). A difference between the ejection fraction medians was observed (p = 0.048). Hospitalization was required twice or more for 45.16% of the patients. The mortality rate was 5.38%.Conclusions: The patients showed significant clinical improvement. The treatment was effective, reducing trivalvular impairment