Blueberry attenuates liver injury in metabolic dysfunction-associated liver disease by promoting the expression of mitofilin/Mic60 in human hepatocytes and inhibiting the production of superoxide / 细胞与分子免疫学杂志

Objective To study the effect and mechanism of blueberry on regulating the mitochondrial inner membrane protein mitofilin/Mic60 in an in vitro model of metabolic dysfunction-associated liver disease (MAFLD). Methods L02 human hepatocytes were induced by free fatty acids (FFA) to establish MAFLD cell model. A normal group, a model group, an 80 μg/mL blueberry treatment group, a Mic60 short hairpin RNA (Mic60 shRNA) transfection group, and Mic60 knockdown combined with an 80 μg/mL blueberry treatment group were established. The intracellular lipid deposition was observed by oil red O staining, and the effect of different concentrations of blueberry pulp on the survival rate of L02 cells treated with FFA was measured by MTT assay. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC), superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) contents were measured by visible spectrophotometry. The expression of reactive oxygen species (ROS) in hepatocytes was observed by fluorescence microscopy, and the mRNA and protein expression of Mic60 were detected by real-time quantitative PCR and Western blot analysis, respectively. Results After 24 hours of FFA stimulation, a large number of red lipid droplets in the cytoplasm of L02 cells was observed, and the survival rate of L02 cells treated with 80 μg/mL blueberry was higher. The results of ALT, AST, TG, TC, MDA and the fluorescence intensity of ROS in blueberry treated group were lower than those in model group, while the levels of SOD, GSH, Mic60 mRNA and protein in blueberry treated group were higher than those in model group. Conclusion Blueberry promotes the expression of Mic60, increases the levels of SOD and GSH in hepatocytes, and reduces the production of ROS, thus alleviating the injury of MAFLD hepatocytes and regulating the disorder of lipid metabolism.

Critical hubs of renal ischemia-reperfusion injury: endoplasmic reticulum-mitochondria tethering complexes / 中华医学杂志(英文版)

Mitochondrial injury and endoplasmic reticulum (ER) stress are considered to be the key mechanisms of renal ischemia-reperfusion (I/R) injury. Mitochondria are membrane-bound organelles that form close physical contact with a specific domain of the ER, known as mitochondrial-associated membranes. The close physical contact between them is mainly restrained by ER-mitochondria tethering complexes, which can play an important role in mitochondrial damage, ER stress, lipid homeostasis, and cell death. Several ER-mitochondria tethering complex components are involved in the process of renal I/R injury. A better understanding of the physical and functional interaction between ER and mitochondria is helpful to further clarify the mechanism of renal I/R injury and provide potential therapeutic targets. In this review, we aim to describe the structure of the tethering complex and elucidate its pivotal role in renal I/R injury by summarizing its role in many important mechanisms, such as mitophagy, mitochondrial fission, mitochondrial fusion, apoptosis and necrosis, ER stress, mitochondrial substance transport, and lipid metabolism.

Evaluation of the therapeutic effect of methylene blue on the liver of rats submitted to ischemia and reperfusion

Abstract Purpose: To analyze the effect of methylene blue (MB) therapy during the liver ischemia-reperfusion injury (I/R) process. Methods: Thirty-five male Wistar rats were used, (70%) submitted to partial ischemia (IR) or not (NIR) (30%) were obtained from the same animal. These animals were divided into six groups: 1) Sham (SH), 2) Sham with MB (SH-MB); 3) I/R, submitted to 60 minutes of partial ischemia and 15 minutes of reperfusion; 4) NI/R, without I/R obtained from the same animal of group I/R; 5) I/R-MB submitted to I/R and MB and 6) NI/R-MB, without I/R. Mitochondrial function was evaluated. Osmotic swelling of mitochondria as well as the determination of malondialdehyde (MDA) was evaluated. Serum (ALT/AST) dosages were also performed. MB was used at the concentration of 15mg/kg, 15 minutes before hepatic reperfusion. Statistical analysis was done by the Mann Whitney test at 5%. Results: State 3 shows inhibition in all ischemic groups. State 4 was increased in all groups, except the I/R-MB and NI/R-MB groups. RCR showed a decrease in all I/R and NI/R groups. Mitochondrial osmotic swelling showed an increase in all I/R NI/R groups in the presence or absence of MB. About MDA, there was a decrease in SH values in the presence of MB and this decrease was maintained in the I/R group. AST levels were increased in all ischemic with or without MB. Conclusions: The methylene blue was not able to restore the mitochondrial parameters studied. Also, it was able to decrease lipid peroxidation, preventing the formation of reactive oxygen species.

Modulation of mitochondrial membrane integrity and ROS formation by high temperature in Saccharomyces cerevisiae

Background Yeast strains are exposed to numerous environmental stresses during industrial alcoholic fermentation. High temperature accumulated acetic acid, enhanced the growth inhibition and decreased ethanol production. Results In this study the influence of high temperature on the cellular and mitochondrial membrane integrity of Saccharomyces cerevisiae as well as reactive oxygen species (ROS) formation was investigated to understand the mechanisms of the high temperature fermentation process. However, increasing the temperature to 42°C resulted in a clear decrease in the cytoplasmic and mitochondrial membrane potential and an increase in intracellular ROS formation. It was also determined that the different thermostability between YZ1 and YF31 strains had a clear correlation with the yeast's intracellular trehalose content of the cell. Finally, random amplified polymorphic DNA (RAPD) was used to explore the genome differences between the YZ1 and YF31 strains. Conclusions Thus, the stability of the mitochondrial membrane and subsequently, the clearance ROS ability could be important factors for the viability of S. cerevisiae at high temperatures.

Suicide attempts among children and adolescents: partial or total injury? / Tentativa de suicídio infanto-juvenil: lesão da parte ou do todo?

This study sought to verify the records on file and the number of cases of attempted suicide among children and adolescents who were attended by Emergency Care health professionals in the municipality of Matozinhos, Minas Gerais, Brazil. Documentary and descriptive research was conducted, the data for which was collected by means of an investigation of Outpatient Records from 2008 to 2010. Of the 73,000 files evaluated, those dealing with cases of attempted suicide among children and adolescents between the age of 3 and 18 years were selected. It was revealed that the health professionals, particularly physicians and nurses, fail to register the cases appropriately, invalidating information about the problem and potential prevention measures. The conclusion reached was that underreporting and the discrepancy of the diagnoses which were not duly referred to the competent agencies require rethinking and reviewing medical practices, and taking a systematic and careful look to address the individual as a complex whole.

Neste estudo procurou-se verificar o registro e o número de casos de tentativa de suicídio entre crianças e adolescentes do município de Matozinhos, Minas Gerais, Brasil, que foram atendidos pelos profissionais de saúde do Pronto-Atendimento. Trata-se de uma pesquisa documental e descritiva, cuja coleta dos dados ocorreu por meio de investigação nas Fichas Ambulatoriais, no período de 2008 a 2010. Das 73.000 fichas levantadas, selecionaram-se aquelas que tratavam de casos de tentativa de suicídio entre crianças e adolescentes do município, com idades entre três e 18 anos. Percebeu-se que os profissionais de saúde, mais especificamente os médicos e enfermeiros, não registram os casos de forma adequada, inviabilizando a informação sobre o problema e as medidas de prevenção. Concluiu-se que a subnotificação, a discrepância dos diagnósticos e o não encaminhamento aos órgãos competentes exigem repensar e rever a prática médica e dirigir um olhar sistematizado e cuidadoso para perceber o sujeito como um todo complexo.

Knockdown of apoptosis-inducing factor disrupts function of respiratory complex I

Recent findings suggest that apoptotic protein apoptosis-inducing factor (AIF) may also play an important non-apoptotic function inside mitochondria. AIF was proposed to be an important component of respiratory chain complex I that is the major producer of superoxide radical. The possible role of AIF is still controversial. Superoxide production could be used as a valuable measure of complex I function, because the majority of superoxide is produced there. Therefore, we employed superoxide-specific mitochondrial fluorescence dye for detection of superoxide production. We studied an impact of AIF knockdown on function of mitochondrial complex I by analyzing superoxide production in selected cell lines. Our results show that tumoral telomerase-positive (TP) AIF knockdown cell lines display significant increase in superoxide production in comparison to control cells, while a non-tumoral cell line and tumoral telomerase-negative cell lines with alternative lengthening of telomeres (ALT) show a decrease in superoxide production. According to these results, we can conclude that AIF knockdown disrupts function of complex I and therefore increases the superoxide production in mitochondria. The distinct effect of AIF depletion in various cell lines could result from recently discovered activity of telomerase in mitochondria of TP cancer cells, but this hypothesis needs further investigation.

Therapeutic Modulation of Apoptosis: Targeting the BCL-2 Family at the Interface of the Mitochondrial Membrane

A vast portion of human disease results when the process of apoptosis is defective. Disorders resulting from inappropriate cell death range from autoimmune and neurodegenerative conditions to heart disease. Conversely, prevention of apoptosis is the hallmark of cancer and confounds the efficacy of cancer therapeutics. In the search for optimal targets that would enable the control of apoptosis, members of the BCL-2 family of anti- and pro-apoptotic factors have figured prominently. Development of BCL-2 antisense approaches, small molecules, and BH3 peptidomimetics has met with both success and failure. Success-because BCL-2 proteins play essential roles in apoptosis. Failure-because single targets for drug development have limited scope. By examining the activity of the BCL-2 proteins in relation to the mitochondrial landscape and drawing attention to the significant mitochondrial membrane alterations that ensue during apoptosis, we demonstrate the need for a broader based multi-disciplinary approach for the design of novel apoptosis-modulating compounds in the treatment of human disease.

Mitochondrial DNA damage associated with lipid peroxidation of the mitochondrial membrane induced by Fe2+-citrate

Desequilíbrio/acúmulo de ferro tem sido implicado em injúria oxidativa associada a diversas doenças degenerativas tais como, hemocromatose hereditária, b-talassemia e ataxia de Friedreich. As mitocôndrias são particularmente sensíveis a estresse oxidativo induzido por ferro - um carregamento alto de ferro em mitocôndrias isoladas pode causar uma extensiva peroxidação lipídica e a permeabilização de membrana. Nesse estudo, nós detectamos e caracterizamos danos do DNA mitocondrial em mitocôndrias isoladas de fígado de rato, expostas ao complexo Fe2+-citrato, um dos complexos de baixo peso molecular. A intensa fragmentação do DNA foi induzida após a incubação das mitocôndrias com o complexo de ferro. A detecção de finais 3' de fosfoglicolato nas quebras de fitas de DNA mitocondrial pelo ensaio 32P-postlabeling sugere um envolvimento de radicais hidroxila na fragmentação do DNA induzido por complexo Fe2+-citrato. Os níveis elevados de 8-oxo-7,8-diidro-2'-desoxiguanosina também sugerem que o estresse oxidativo induzido por Fe2+-citrato causa danos no DNA mitocondrial. Em conclusão, nossos resultados mostram que a peroxidação lipídica mediada por ferro esteve associada com severos danos do DNA mitocondrial derivados de ataque direto das espécies reativas de oxigênio.