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1.
Arq Bras Cardiol ; 116(2): 315-322, 2021 02.
Artigo em Inglês, Português | MEDLINE | ID: mdl-33656082

RESUMO

BACKGROUND: Doxorubicin is associated with cardiotoxicity and late cardiac morbidity. Heme is related to cellular oxidative stress. However, its specific regulation in cardiomyocytes under doxorubicin effects has not yet been documented. OBJECTIVE: This study seeks to evaluate the changing profiles of rate-limiting enzymes in the heme metabolism pathway under the effect of doxorubicin. METHODS: H9c2 cardiomyocytes were incubated with doxorubicin at different concentrations (1,2,5,10µM respectively). The real-time PCR and Western Blot were used to determine the mRNA and protein expression for four pivotal enzymes (ALAS1, ALAS2, HOX-1, and HOX-2) regulating cellular heme metabolism, as well as the levels of heme were detected by ELISA. p<0.01 was considered significant. RESULTS: This study observed a dose-dependent changing pattern in heme levels in H9c2 cells with the highest level at the 5µM concentration for doxorubicin, which occurred synchronously with the highest upregulation level of ALAS1, as well as the degradative enzymes, HOX-1, and HOX-2 in mRNA and protein expression. By contrast, ALAS2, contrary to the increasing concentrations of doxorubicin, was found to be progressively down-regulated. CONCLUSION: The increase in ALAS1 expression may play a potential role in the heme level elevation when H9c2 cardiomyocyte was exposed to doxorubicin and may be a potential therapeutic target for doxorubicin-induced myocardial toxicity. (Arq Bras Cardiol. 2021; 116(2):315-322).


Assuntos
Doxorrubicina , Miócitos Cardíacos , 5-Aminolevulinato Sintetase/metabolismo , Cardiotoxicidade , Heme/metabolismo , Humanos , Miócitos Cardíacos/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo
3.
Int J Mol Sci ; 22(3)2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33530421

RESUMO

Plasma hemopexin (HPX) is the key antioxidant protein of the endogenous clearance pathway that limits the deleterious effects of heme released from hemoglobin and myoglobin (the term "heme" is used in this article to denote both the ferrous and ferric forms). During intra-vascular hemolysis, heme partitioning to protein and lipid increases as the plasma concentration of HPX declines. Therefore, the development of HPX as a replacement therapy during high heme stress could be a relevant intervention for hemolytic disorders. A logical approach to enhance HPX yield involves recombinant production strategies from human cell lines. The present study focuses on a biophysical assessment of heme binding to recombinant human HPX (rhHPX) produced in the Expi293FTM (HEK293) cell system. In this report, we examine rhHPX in comparison with plasma HPX using a systematic analysis of protein structural and functional characteristics related to heme binding. Analysis of rhHPX by UV/Vis absorption spectroscopy, circular dichroism (CD), size-exclusion chromatography (SEC)-HPLC, and catalase-like activity demonstrated a similarity to HPX fractionated from plasma. In particular, the titration of HPX apo-protein(s) with heme was performed for the first time using a wide range of heme concentrations to model HPX-heme interactions to approximate physiological conditions (from extremely low to more than two-fold heme molar excess over the protein). The CD titration data showed an induced bisignate CD Soret band pattern typical for plasma and rhHPX versions at low heme-to-protein molar ratios and demonstrated that further titration is dependent on the amount of protein-bound heme to the extent that the arising opposite CD couplet results in a complete inversion of the observed CD pattern. The data generated in this study suggest more than one binding site in both plasma and rhHPX. Furthermore, our study provides a useful analytical platform for the detailed characterization of HPX-heme interactions and potentially novel HPX fusion constructs.


Assuntos
Heme/metabolismo , Hemopexina/metabolismo , Proteínas Recombinantes , Transporte Biológico , Dicroísmo Circular , Heme/química , Hemopexina/química , Humanos , Peróxido de Hidrogênio/metabolismo , Metemalbumina , Óxido Nítrico/metabolismo , Espectroscopia Fotoeletrônica , Ligação Proteica , Temperatura
4.
BMC Complement Med Ther ; 21(1): 71, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33607987

RESUMO

BACKGROUND: In previous studies, Cassia spectabilis DC leaf has shown a good antiplasmodial activity. Therefore, this study is a follow-up study of the extract of leaf of C. spectabilis DC on its in vitro and in vivo antiplasmodial activity and mechanism as an antimalarial. METHODS: The extract was fractionated, sub-fractionated and isolated to obtain the purified compound. In vitro antiplasmodial activity test against Plasmodium falciparum to find out the active compound. In vivo test against P. berghei ANKA-infected mice was conducted to determine prophylactic activity and antiplasmodial activity either alone or in combination with artesunate. The inhibition of heme detoxification test as one of the antimalarial mechanisms was carried out using the Basilico method. RESULTS: The results showed that active antimalarial compound isolated from C. spectabilis DC leaf had a structural pattern that was identical to (-)-7-hydroxycassine. Prophylactic test of 90% ethanolic extract of C. spectabilis DC leaf alone against P. berghei ANKA-infected mice obtained the highest percentage inhibition was 68.61%, while positive control (doxycycline 13 mg/kg) was 73.54%. In combination with artesunate, 150 mg/kg three times a day of C. spectabilis DC (D0-D2) + artesunate (D2) was better than the standard combination of amodiaquine + artesunate where the inhibition percentages were 99.18 and 92.88%, respectively. The IC50 of the extract for the inhibitory activity of heme detoxification was 0.375 mg/ml which was better than chloroquine diphosphate (0.682 mg/ml). CONCLUSION: C. spectabilis DC leaf possessed potent antiplasmodial activity and may offer a potential agent for effective and affordable antimalarial phytomedicine.


Assuntos
Antimaláricos/farmacologia , Cassia/química , Heme/metabolismo , Malária/parasitologia , Extratos Vegetais/farmacologia , Plasmodium berghei/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/isolamento & purificação , Antimaláricos/uso terapêutico , Artesunato/uso terapêutico , Cloroquina/análogos & derivados , Cloroquina/farmacologia , Cetonas , Malária/tratamento farmacológico , Masculino , Camundongos Endogâmicos BALB C , Fitoterapia , Piperidinas , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , Plasmodium berghei/metabolismo , Plasmodium falciparum/metabolismo
5.
Nat Commun ; 12(1): 1104, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597527

RESUMO

Photosynthetic electron transfers occur through multiple components ranging from small soluble proteins to large integral membrane protein complexes. Co-crystallization of a bacterial photosynthetic electron transfer complex that employs weak hydrophobic interactions was achieved by using high-molar-ratio mixtures of a soluble donor protein (high-potential iron-sulfur protein, HiPIP) with a membrane-embedded acceptor protein (reaction center, RC) at acidic pH. The structure of the co-complex offers a snapshot of a transient bioenergetic event and revealed a molecular basis for thermodynamically unfavorable interprotein electron tunneling. HiPIP binds to the surface of the tetraheme cytochrome subunit in the light-harvesting (LH1) complex-associated RC in close proximity to the low-potential heme-1 group. The binding interface between the two proteins is primarily formed by uncharged residues and is characterized by hydrophobic features. This co-crystal structure provides a model for the detailed study of long-range trans-protein electron tunneling pathways in biological systems.


Assuntos
Proteínas de Bactérias/química , Chromatiaceae/metabolismo , Proteínas com Ferro-Enxofre/química , Complexos de Proteínas Captadores de Luz/química , Fotossíntese , Complexo de Proteínas do Centro de Reação Fotossintética/química , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cristalização , Citocromos/química , Citocromos/metabolismo , Transporte de Elétrons , Heme/análogos & derivados , Heme/química , Heme/metabolismo , Proteínas com Ferro-Enxofre/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Modelos Moleculares , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Conformação Proteica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
6.
Nat Commun ; 12(1): 1086, 2021 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-33597529

RESUMO

The dynamics of photodissociation and recombination in heme proteins represent an archetypical photochemical reaction widely used to understand the interplay between chemical dynamics and reaction environment. We report a study of the photodissociation mechanism for the Fe(II)-S bond between the heme iron and methionine sulfur of ferrous cytochrome c. This bond dissociation is an essential step in the conversion of cytochrome c from an electron transfer protein to a peroxidase enzyme. We use ultrafast X-ray solution scattering to follow the dynamics of Fe(II)-S bond dissociation and 1s3p (Kß) X-ray emission spectroscopy to follow the dynamics of the iron charge and spin multiplicity during bond dissociation. From these measurements, we conclude that the formation of a triplet metal-centered excited state with anti-bonding Fe(II)-S interactions triggers the bond dissociation and precedes the formation of the metastable Fe high-spin quintet state.


Assuntos
Citocromos c/metabolismo , Compostos Ferrosos/metabolismo , Ferro/metabolismo , Metais/metabolismo , Metionina/metabolismo , Citocromos c/química , Transporte de Elétrons/efeitos da radiação , Compostos Ferrosos/química , Heme/química , Heme/metabolismo , Ferro/química , Metais/química , Metionina/química , Simulação de Dinâmica Molecular , Fotólise , Espectrometria por Raios X
7.
Ecotoxicol Environ Saf ; 212: 112018, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33550076

RESUMO

The underlying mechanisms of microRNAs (miRNAs) in regulating nanoplastic toxicity are still largely unclear in organisms. In nanopolystyrene (NPS) exposed Caenorhabditis elegans, the expression of mir-76 (a neuronal miRNA) was significantly decreased, and the mir-76 mutant was resistant to the toxicity of NPS. The aim of this study was to determine the molecular basis of mir-76 in controlling NPS toxicity in nematodes. The mir-76 mutation increased expression of glb-10 encoding a globin protein in NPS (1 µg/L) exposed nematodes. Exposure to NPS (1-100 µg/L) increased the glb-10 expression, and the glb-10(RNAi) worm was susceptible to NPS toxicity in inducing reactive oxygen species (ROS) production and in decreasing locomotion behavior. Using ROS production and locomotion behavior as endpoints, mutation of glb-10 inhibited resistance of mir-76 mutant to NPS toxicity, and neuronal overexpression of mir-76 inhibited the resistance to NPS toxicity in nematodes overexpressing neuronal glb-10 containing 3' untranslated region (3'UTR). Thus, GLB-10 functioned as a target of mir-76 in the neurons to regulate the NPS toxicity. Moreover, a signaling cascade of HRG-7-HRG-5 required for the control of heme homeostasis was identified to function downstream of neuronal GLB-10 to regulate the NPS toxicity. In this signaling cascade, the neuronal HRG-7 regulated the NPS toxicity by antagonizing function of intestinal HRG-5. Furthermore, in the intestine, HRG-5 controlled NPS toxicity by inhibiting functions of hypoxia-inducible transcriptional factor HIF-1 and transcriptional factor ELT-2. Our results highlight the crucial function of heme homeostasis related signaling in regulating the NPS toxicity in organisms.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/efeitos dos fármacos , Heme/metabolismo , Homeostase , MicroRNAs/genética , Nanoestruturas/toxicidade , Poliestirenos/toxicidade , Animais , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Intestinos/efeitos dos fármacos , Nanoestruturas/química , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Poliestirenos/química , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
8.
Int J Mol Sci ; 22(3)2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33498330

RESUMO

Proteins have been used as building blocks to provide various supramolecular structures in efforts to develop nano-biomaterials possessing broad biological functionalities. A series of unique structures have been obtained from the engineering of hemoproteins which contain the iron porphyrin known as heme, as a prosthetic group. This work in developing assembling systems is extended using cytochrome b562, a small electron transfer hemoprotein engineered to include an externally-attached heme moiety. The engineered units, which form a one-dimensional assembly via interprotein heme-heme pocket interactions, are conjugated to an apo-form of hexameric tyrosine-coordinated hemoprotein (apoHTHP) to provide a branching unit promoting the assembly of a star-shaped structure. The incorporation of the heme moiety attached to the protein surface of cytochrome b562 into apoHTHP can be accelerated by elevating the reaction temperature to generate a new assembly. The formation of a new larger assembly structure was confirmed by size exclusion chromatography. The ratio of the heme-containing units in the assemblies was analyzed by UV-Vis spectroscopy and the population of protein units estimated from SDS PAGE suggests the presence of plausible star-shaped structures, which are supported by hydrodynamic diameter data obtained by dynamic light scattering.


Assuntos
Citocromos b/química , Heme/química , Multimerização Proteica , Sítios de Ligação , Citocromos b/metabolismo , Heme/metabolismo , Ligação Proteica
9.
Int J Mol Sci ; 22(2)2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33445488

RESUMO

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease with low clinical penetrance, caused by mutations in the hydroxymethylbilane synthase (HMBS) gene, which encodes the third enzyme in the haem biosynthesis pathway. In susceptible HMBS mutation carriers, triggering factors such as hormonal changes and commonly used drugs induce an overproduction and accumulation of toxic haem precursors in the liver. Clinically, this presents as acute attacks characterised by severe abdominal pain and a wide array of neurological and psychiatric symptoms, and, in the long-term setting, the development of primary liver cancer, hypertension and kidney failure. Treatment options are few, and therapies preventing the development of symptomatic disease and long-term complications are non-existent. Here, we provide an overview of the disorder and treatments already in use in clinical practice, in addition to other therapies under development or in the pipeline. We also introduce the pathomechanistic effects of HMBS mutations, and present and discuss emerging therapeutic options based on HMBS stabilisation and the regulation of proteostasis. These are novel mechanistic therapeutic approaches with the potential of prophylactic correction of the disease by totally or partially recovering the enzyme functionality. The present scenario appears promising for upcoming patient-tailored interventions in AIP.


Assuntos
Porfiria Aguda Intermitente/terapia , Alelos , Animais , Terapia Combinada , Gerenciamento Clínico , Suscetibilidade a Doenças , Predisposição Genética para Doença , Heme/metabolismo , Humanos , Hidroximetilbilano Sintase/química , Hidroximetilbilano Sintase/genética , Redes e Vias Metabólicas , Mutação , Porfiria Aguda Intermitente/diagnóstico , Porfiria Aguda Intermitente/etiologia , Relação Estrutura-Atividade , Resultado do Tratamento
10.
Nat Commun ; 12(1): 380, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452262

RESUMO

Glycosidases are phylogenetically widely distributed enzymes that are crucial for the cleavage of glycosidic bonds. Here, we present the exceptional properties of a putative ancestor of bacterial and eukaryotic family-1 glycosidases. The ancestral protein shares the TIM-barrel fold with its modern descendants but displays large regions with greatly enhanced conformational flexibility. Yet, the barrel core remains comparatively rigid and the ancestral glycosidase activity is stable, with an optimum temperature within the experimental range for thermophilic family-1 glycosidases. None of the ∼5500 reported crystallographic structures of ∼1400 modern glycosidases show a bound porphyrin. Remarkably, the ancestral glycosidase binds heme tightly and stoichiometrically at a well-defined buried site. Heme binding rigidifies this TIM-barrel and allosterically enhances catalysis. Our work demonstrates the capability of ancestral protein reconstructions to reveal valuable but unexpected biomolecular features when sampling distant sequence space. The potential of the ancestral glycosidase as a scaffold for custom catalysis and biosensor engineering is discussed.


Assuntos
Bactérias/enzimologia , Eucariotos/enzimologia , Glicosídeo Hidrolases/metabolismo , Heme/metabolismo , Regulação Alostérica , Sequência de Aminoácidos/genética , Bactérias/genética , Cristalografia por Raios X , Eucariotos/genética , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/ultraestrutura , Simulação de Dinâmica Molecular , Filogenia , Estrutura Secundária de Proteína , Homologia de Sequência de Aminoácidos
11.
Biochim Biophys Acta Mol Cell Res ; 1868(1): 118881, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33022276

RESUMO

Heme, as a hydrophobic iron-containing organic ring, is lipid soluble and can interact with biological membranes. The very same properties of heme that nature exploits to support life also renders heme potentially cytotoxic. In order to utilize heme, while also mitigating its toxicity, cells are challenged to tightly control the concentration and bioavailability of heme. On the bright side, it is reasonable to envision that, analogous to other transition metals, a combination of membrane-bound transporters, soluble carriers, and chaperones coordinate heme trafficking to subcellular compartments. However, given the dual properties exhibited by heme as a transition metal and lipid, it is compelling to consider the dark side: the potential role of non-proteinaceous biomolecules including lipids and nucleic acids that bind, sequester, and control heme trafficking and bioavailability. The emergence of inter-organellar membrane contact sites, as well as intracellular vesicles derived from various organelles, have raised the prospect that heme can be trafficked through hydrophobic channels. In this review, we aim to focus on heme delivery without deliverers - an alternate paradigm for the regulation of heme homeostasis through chaperone-less pathways for heme trafficking.


Assuntos
Heme/metabolismo , Homeostase/efeitos dos fármacos , Lipídeos/química , Transporte Proteico/genética , Citotoxinas/farmacologia , Heme/química , Homeostase/genética , Ferro/química , Ferro/metabolismo , Metais/química , Chaperonas Moleculares/química , Solubilidade/efeitos dos fármacos
12.
J Agric Food Chem ; 69(1): 397-403, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33351608

RESUMO

The effect of gallic acid (GA) on the redox state of hemoglobin (Hb) and the structural mechanism upon the Hb-GA interaction were investigated. Results indicated that GA exhibited antioxidant and pro-oxidant effects on Hb, which depended on its concentration and the redox state of Hb. The antioxidant capacity of GA contributed to the inhibition of free iron release from Hb. GA could bind to the central cavity of Hb and interacted with the heme moiety through direct hydrophobic contacts as indicated by docking analysis, but GA did not disrupt the heme structure. Conversely, GA increased the compactness of the Hb molecule and might narrow the crevice around the heme pocket, which contributed to the inhibition of Hb autoxidation and the free iron release. Results provided significant insights into the interaction of GA with redox-active Hb, which is beneficial to the application of GA in relative meat and blood products.


Assuntos
Ácido Gálico/química , Hemoglobinas/química , Hemoglobinas/metabolismo , Animais , Antioxidantes/química , Ácido Gálico/metabolismo , Heme/química , Heme/metabolismo , Carne/análise , Músculos/química , Músculos/metabolismo , Oxirredução , Conformação Proteica em alfa-Hélice , Suínos
13.
J Ethnopharmacol ; 265: 113389, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32920134

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: In traditional Chinese medicine (TCM) theory, "Qi" is classified as energetic essence supporting the life activities in human. "Blood" is categorized as nourishing essence and circulating in the body. "Blood" and "Qi" have an intimate relationship. Astragali Radix (AR; root of Astragalus membranaceus (Fisch.) Bge. Var. mongholicus (Bge.) Hsiao) has a broad spectrum of application for "Qi-Blood" enrichment. Astragaloside IV, a major saponin in AR, has therapeutic functions in erythropoietic, cardiovascular and immune systems. However, the efficacy of astragaloside IV in erythrophagocytosis has not been elucidated. AIM OF THE STUDY: The possible functions of astragaloside IV in heme iron recycling during erythrophagocytosis in cultured macrophage were elucidated. METHODS: The translational and transcriptional expressions of heme recycling enzymes were determined after incubating of astragaloside IV for 24 h in cultured macrophage. RESULTS: In astragaloside IV-treated macrophage, the expressions, both RNA and protein levels, of regulators of heme recycling, e.g. heme oxygenase-1 (HO-1), ferroportin (FPN), biliverdin reductase A and B (BVRA, BVRB), were markedly induced in dose-dependent manners. In parallel, the transcriptional activity of antioxidant response element, cloned within an expression vector as pARE-Luc and transfected in cultured macrophages, was markedly induced after a challenge with astragaloside IV in a dose-dependent manner. Moreover, the translocation of Nrf2, a transcriptional factor in regulating expression of heme recycling protein, was induced by astragaloside IV, leading to an enrichment at nucleus fraction. CONCLUSION: Astragaloside IV shed lights in enhancing the expression of heme recycle proteins via Nrf2/ARE signaling pathway.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Macrófagos/efeitos dos fármacos , Saponinas/farmacologia , Triterpenos/farmacologia , Animais , Elementos de Resposta Antioxidante/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/química , Heme/metabolismo , Heme Oxigenase-1/metabolismo , Macrófagos/metabolismo , Medicina Tradicional Chinesa , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Células RAW 264.7 , Saponinas/isolamento & purificação , Transdução de Sinais/efeitos dos fármacos , Triterpenos/isolamento & purificação
14.
Int J Mol Sci ; 22(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374506

RESUMO

Over the past decades, substantial work has established that hemoglobin oxidation and heme release play a pivotal role in hemolytic/hemorrhagic disorders. Recent reports have shown that oxidized hemoglobins, globin-derived peptides, and heme trigger diverse biological responses, such as toll-like receptor 4 activation with inflammatory response, reprogramming of cellular metabolism, differentiation, stress, and even death. Here, we discuss these cellular responses with particular focus on their mechanisms that are linked to the pathological consequences of hemorrhage and hemolysis. In recent years, endogenous gasotransmitters, such as carbon monoxide (CO) and hydrogen sulfide (H2S), have gained a lot of interest in connection with various human pathologies. Thus, many CO and H2S-releasing molecules have been developed and applied in various human disorders, including hemolytic and hemorrhagic diseases. Here, we discuss our current understanding of oxidized hemoglobin and heme-induced cell and tissue damage with particular focus on inflammation, cellular metabolism and differentiation, and endoplasmic reticulum stress in hemolytic/hemorrhagic human diseases, and the potential beneficial role of CO and H2S in these pathologies. More detailed mechanistic insights into the complex pathology of hemolytic/hemorrhagic diseases through heme oxygenase-1/CO as well as H2S pathways would reveal new therapeutic approaches that can be exploited for clinical benefit.


Assuntos
Monóxido de Carbono/uso terapêutico , Heme Oxigenase (Desciclizante)/metabolismo , Hemólise/efeitos dos fármacos , Sulfeto de Hidrogênio/uso terapêutico , Púrpura de Schoenlein-Henoch/tratamento farmacológico , Púrpura de Schoenlein-Henoch/metabolismo , Animais , Monóxido de Carbono/metabolismo , Monóxido de Carbono/farmacologia , Gerenciamento Clínico , Suscetibilidade a Doenças , Metabolismo Energético , Heme/metabolismo , Heme Oxigenase-1/metabolismo , Hemoglobinas/química , Hemoglobinas/metabolismo , Humanos , Sulfeto de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/farmacologia , Metabolismo dos Lipídeos , Lipoproteínas LDL/metabolismo , Monócitos/imunologia , Monócitos/metabolismo , Oxirredução/efeitos dos fármacos , Peptídeos/metabolismo , Púrpura de Schoenlein-Henoch/diagnóstico , Púrpura de Schoenlein-Henoch/etiologia , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismo
15.
Int J Mol Sci ; 21(24)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353225

RESUMO

The class of tetrapyrrol "coordination complexes" called hemes are prosthetic group components of metalloproteins including hemoglobin, which provide functionality to these physiologically essential macromolecules by reversibly binding diatomic gasses, notably O2, which complexes to ferrous (reduced/Fe(II)) iron within the heme porphyrin ring of hemoglobin in a pH- and PCO2-dependent manner-thus allowing their transport and delivery to anatomic sites of their function. Here, pathologies associated with aberrant heme degradation are explored in the context of their underlying mechanisms and emerging medical countermeasures developed using heme oxygenase (HO), its major degradative enzyme and bioactive metabolites produced by HO activity. Tissue deposits of heme accumulate as a result of the removal of senescent or damaged erythrocytes from circulation by splenic macrophages, which destroy the cells and internal proteins, including hemoglobin, leaving free heme to accumulate, posing a significant toxicogenic challenge. In humans, HO uses NADPH as a reducing agent, along with molecular oxygen, to degrade heme into carbon monoxide (CO), free ferrous iron (FeII), which is sequestered by ferritin protein, and biliverdin, subsequently metabolized to bilirubin, a potent inhibitor of oxidative stress-mediated tissue damage. CO acts as a cellular messenger and augments vasodilation. Nevertheless, disease- or trauma-associated oxidative stressors sufficiently intense to overwhelm HO may trigger or exacerbate a wide range of diseases, including cardiovascular and neurologic syndromes. Here, strategies are described for counteracting the effects of aberrant heme degradation, with a particular focus on "bioflavonoids" as HO inducers, shown to cause amelioration of severe inflammatory diseases.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/fisiopatologia , Flavonoides/farmacologia , Heme/metabolismo , Inflamação/tratamento farmacológico , Inflamação/fisiopatologia , Doenças do Sistema Nervoso/tratamento farmacológico , Doenças do Sistema Nervoso/fisiopatologia , Animais , Heme Oxigenase-1/metabolismo , Humanos
16.
J Breath Res ; 14(4): 047105, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33021205

RESUMO

The influence of breath sampling on exhaled carbon monoxide (eCO) and related pulmonary gas exchange parameters is investigated in a study with 32 healthy non-smokers. Mid-infrared tunable diode laser absorption spectroscopy and well-controlled online sampling is used to precisely measure mouth- and nose-exhaled CO expirograms at exhalation flow rates (EFRs) of 250, 120 and 60 ml s-1, and for 10 s of breath-holding followed by exhalation at 120 ml s-1. A trumpet model with axial diffusion is employed to fit simulated exhalation profiles to the experimental expirograms, which provides equilibrium airway and alveolar CO concentrations and the average lung diffusing capacity in addition to end-tidal concentrations. For all breathing maneuvers, excellent agreement is found between mouth- and nose-exhaled end-tidal CO (ETCO), and the individual values for ETCO and alveolar diffusing capacity are consistent across maneuvers. The eCO parameters clearly show a dependence on EFR, where the lung diffusing capacity increases with EFR, while ETCO slightly decreases. End-tidal CO is largely independent of ambient air CO and alveolar diffusing capacity. While airway CO is slightly higher than, and correlates strongly with, ambient air CO, and there is a weak correlation with ETCO, the results point to negligible endogenous airway CO production in healthy subjects. An EFR of around 120 ml s-1 can be recommended for clinical eCO measurements. The employed method provides means to measure variations in endogenous CO, which can improve the interpretation of exhaled CO concentrations and the diagnostic value of eCO tests in clinical studies. Clinical trial registration number: 2017/306-31.


Assuntos
Testes Respiratórios/métodos , Monóxido de Carbono/análise , Expiração , Manejo de Espécimes , Adulto , Feminino , Heme/metabolismo , Humanos , Masculino , Boca , Nariz , Reologia
17.
Nat Commun ; 11(1): 4837, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973183

RESUMO

ATP synthesis and thermogenesis are two critical outputs of mitochondrial respiration. How these outputs are regulated to balance the cellular requirement for energy and heat is largely unknown. Here we show that major facilitator superfamily domain containing 7C (MFSD7C) uncouples mitochondrial respiration to switch ATP synthesis to thermogenesis in response to heme. When heme levels are low, MSFD7C promotes ATP synthesis by interacting with components of the electron transport chain (ETC) complexes III, IV, and V, and destabilizing sarcoendoplasmic reticulum Ca2+-ATPase 2b (SERCA2b). Upon heme binding to the N-terminal domain, MFSD7C dissociates from ETC components and SERCA2b, resulting in SERCA2b stabilization and thermogenesis. The heme-regulated switch between ATP synthesis and thermogenesis enables cells to match outputs of mitochondrial respiration to their metabolic state and nutrient supply, and represents a cell intrinsic mechanism to regulate mitochondrial energy metabolism.


Assuntos
Trifosfato de Adenosina/metabolismo , Heme/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Receptores Virais/metabolismo , Termogênese/fisiologia , Animais , Deficiência de Citocromo-c Oxidase , Complexo III da Cadeia de Transporte de Elétrons , Complexo IV da Cadeia de Transporte de Elétrons , Metabolismo Energético/fisiologia , Técnicas de Inativação de Genes , Células HEK293 , Humanos , Proteínas de Membrana Transportadoras/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Domínios Proteicos , Receptores Virais/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo , Transdução de Sinais , Células THP-1
18.
Nat Commun ; 11(1): 4813, 2020 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-32968076

RESUMO

Artemisinins have revolutionized the treatment of Plasmodium falciparum malaria; however, resistance threatens to undermine global control efforts. To broadly explore artemisinin susceptibility in apicomplexan parasites, we employ genome-scale CRISPR screens recently developed for Toxoplasma gondii to discover sensitizing and desensitizing mutations. Using a sublethal concentration of dihydroartemisinin (DHA), we uncover the putative transporter Tmem14c whose disruption increases DHA susceptibility. Screens performed under high doses of DHA provide evidence that mitochondrial metabolism can modulate resistance. We show that disrupting a top candidate from the screens, the mitochondrial protease DegP2, lowers porphyrin levels and decreases DHA susceptibility, without significantly altering parasite fitness in culture. Deleting the homologous gene in P. falciparum, PfDegP, similarly lowers heme levels and DHA susceptibility. These results expose the vulnerability of heme metabolism to genetic perturbations that can lead to increased survival in the presence of DHA.


Assuntos
Antimaláricos/farmacologia , Artemisininas/farmacologia , Resistência a Medicamentos/genética , Testes Genéticos/métodos , Heme/genética , Heme/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Técnicas de Inativação de Genes , Humanos , Malária Falciparum/tratamento farmacológico , Proteínas de Membrana Transportadoras/metabolismo , Mutação , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Toxoplasma/efeitos dos fármacos , Toxoplasma/genética
19.
PLoS One ; 15(9): e0239030, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915914

RESUMO

Hemopexin and α1-microglobulin act as scavengers to eliminate free heme-groups responsible for hemoglobin-induced oxidative stress. The present study evaluated maternal and fetal plasma concentrations of these scavengers in the different phenotypes of placenta-mediated disorders. Singleton pregnancies with normotensive fetal growth restriction [FGR] (n = 47), preeclampsia without FGR (n = 45) and preeclampsia with FGR (n = 51) were included prospectively as well as uncomplicated pregnancies (n = 49). Samples were collected at delivery and ELISA analysis was applied to measure the hemopexin and α1-microglobulin concentrations. In maternal blood in preeclampsia with and without FGR, hemopexin was significantly lower (p = 0.003 and p<0.001, respectively) and α1-microglobulin was significantly higher (p<0.001 in both) whereas no difference existed in normotensive FGR mothers compared to controls. In contrast, in fetal blood in growth restricted fetuses with and without preeclampsia, both hemopexin and α1-microglobulin were significantly lower (p<0.001 and p = 0.001 for hemopexin, p = 0.016 and p = 0.013 for α1-microglobulin, respectively) with no difference in fetuses from preeclampsia without FGR in comparison to controls. Thus, hemopexin and α1-microglobulin present significantly altered concentrations in maternal blood in the maternal disease -preeclampsia- and in cord blood in the fetal disease -FGR-, which supports their differential role in placenta-mediated disorders in accordance with the clinical presentation of these disorders.


Assuntos
alfa-Globulinas/metabolismo , Retardo do Crescimento Fetal/sangue , Heme/metabolismo , Hemopexina/metabolismo , Pré-Eclâmpsia/sangue , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Sangue Fetal/metabolismo , Retardo do Crescimento Fetal/etiologia , Depuradores de Radicais Livres/sangue , Humanos , Recém-Nascido , Estresse Oxidativo , Pré-Eclâmpsia/etiologia , Gravidez , Estudos Prospectivos
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