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Glutamine metabolism, governed by enzymes including glutaminase (GLS1 and GLS2), has a pivotal role in cancer progression. The objective of this study was to determine whether GLS2 transcription levels are associated with oral squamous cell carcinoma (OSCC) when compared to matched adjacent normal tissues. Primary tumour and adjacent normal tissues were collected from 51 OSCC patients, and GLS2 mRNA expression analysis was conducted using real-time qPCR. Additionally, The Cancer Genome Atlas–Head and Neck Squamous Cell Carcinoma (TCGA-HNSCC) dataset was utilized to examine GLS2 expression in relation to clinicopathological features, the prognosis, and tumour immune cell infiltration. A significantly reduced expression of GLS2 mRNA was found in the OSCC tissues when compared to the matched adjacent normal tissue samples (P < 0.001), which aligned with the results from the TCGA-HNSCC dataset and immunohistochemistry. Moreover, GLS2 mRNA expression was associated with clinicopathological features including tumour stage, grade, and human papillomavirus status (all P < 0.05), predicted a poorer prognosis (P = 0.024), and was correlated with tumour immune cell infiltration (all P < 0.05) in head and neck squamous cell carcinoma. Functional pathway analysis indicated its involvement in cell proliferation and metabolic cycles. GLS2 dysregulation is linked to oral cancer, suggesting its potential as a predictive prognostic marker for OSCC. Furthermore, targeting glutaminases via GLS2 may represent a promising therapeutic strategy for OSCC treatment. [ABSTRACT FROM AUTHOR]

Plastid retrograde signaling plays a key role in coordinating the expression of plastid genes and photosynthesis-associated nuclear genes (PhANGs). Although plastid retrograde signaling can be substantially compromised by mitochondrial dysfunction, it is not yet clear whether specific mitochondrial factors are required to regulate plastid retrograde signaling. Here, we show that mitochondrial ATP synthase beta-subunit mutants with decreased ATP synthase activity are impaired in plastid retrograde signaling in Arabidopsis thaliana. Transcriptome analysis revealed that the expression levels of PhANGs were significantly higher in the mutants affected in the AT5G08670 gene encoding the mitochondrial ATP synthase beta-subunit, compared to wild-type (WT) seedlings when treated with lincomycin (LIN) or norflurazon (NF). Further studies indicated that the expression of nuclear genes involved in chloroplast and mitochondrial retrograde signaling was affected in the AT5G08670 mutant seedlings treated with LIN. These changes might be linked to the modulation of some transcription factors (TFs), such as LHY (Late Elongated Hypocotyl), PIF (Phytochrome-Interacting Factors), MYB, WRKY, and AP2/ERF (Ethylene Responsive Factors). These findings suggest that the activity of mitochondrial ATP synthase significantly influences plastid retrograde signaling. [ABSTRACT FROM AUTHOR]

Protein posttranslational modifications are important factors that mediate the fine regulation of signaling molecules. O-linked β-N-acetylglucosamine-modification (O-GlcNAcylation) is a monosaccharide modification on N-acetylglucosamine linked to the hydroxyl terminus of serine and threonine of proteins. O-GlcNAcylation is responsive to cellular stress as a reversible and posttranslational modification of nuclear, mitochondrial and cytoplasmic proteins. Mitochondrial proteins are the main targets of O-GlcNAcylation and O-GlcNAcylation is a key regulator of mitochondrial homeostasis by directly regulating the mitochondrial proteome or protein activity and function. Disruption of O-GlcNAcylation is closely related to mitochondrial dysfunction. More importantly, the O-GlcNAcylation of cardiac proteins has been proven to be protective or harmful to cardiac function. Mitochondrial homeostasis is crucial for cardiac contractile function and myocardial cell metabolism, and the imbalance of mitochondrial homeostasis plays a crucial role in the pathogenesis of cardiovascular diseases (CVDs). In this review, we will focus on the interactions between protein O-GlcNAcylation and mitochondrial homeostasis and provide insights on the role of mitochondrial protein O-GlcNAcylation in CVDs. [ABSTRACT FROM AUTHOR]

An increasing number of studies point to an association between mitochondrial proteins (MPs) and lung cancer (LC). However, the causal relationship between MPs and LC remains unclear. Consequently, our study employed a bidirectional Mendelian randomization (MR) analysis to explore the causal association between MPs and different pathological types of LC. A two-sample MR study was performed using the genome-wide association study (GWAS) data publicly available. We applied the primary inverse variance weighted (IVW) method along with additional MR methods to validate the causality between MPs and different pathological types of LC. To ensure the robustness of our findings, sensitivity analyses were employed. Moreover, we performed a bi-directional MR analysis to determine the direction of the causal association. We identified a total of seven MPs had significant causal relationships on overall LC, lung squamous cell carcinoma (LUSC), and small cell lung carcinoma (SCLC). We found two MPs had significant associations with overall LC, four MPs had significant associations with LUSC, and four MPs had significant associations with SCLC. Additionally, an MP was found to have a nominal relationship with LUSC. Moreover, no causality was found between MPs and lung adenocarcinoma (LUAD). Bidirectional MR showed no reverse effect between identified MPs and different pathological types of LC. In general, our findings of this MR study suggest causal associations of specific MPs with overall LC, LUSC, and SCLC. However, no such causality was found in LUAD. [ABSTRACT FROM AUTHOR]

Background: Friedreich ataxia is a progressive multisystem disorder caused by deficiency of the protein frataxin; a small mitochondrial protein involved in iron sulfur cluster synthesis. Two types of frataxin exist: FXN-M, found in most cells, and FXN-E, found almost exclusively in red blood cells. Treatments in clinical trials include frataxin restoration by gene therapy, protein replacement, and epigenetic therapies, all of which necessitate sensitive assays for assessing frataxin levels. Methods: In the present study, we have used a triple quadrupole mass spectrometry-based assay to examine the features of both types of frataxin levels in blood in a large heterogenous cohort of 106 patients with FRDA. Results: Frataxin levels (FXN-E and FXN M) were predicted by GAA repeat length in regression models (R2 values = 0.51 and 0.27, respectively), and conversely frataxin levels predicted clinical status as determined by modified Friedreich Ataxia Rating scale scores and by disability status (R2 values = 0.13–0.16). There was no significant change in frataxin levels in individual subjects over time, and apart from start codon mutations, FXN-E and FXN-M levels were roughly equal. Accounting for hemoglobin levels in a smaller sub-cohort improved prediction of both FXN-E and FXN-M levels from R2 values of (0.3–0.38 to 0.20–0.51). Conclusion: The present data show that assay of FXN-M and FXN-E levels in blood provides an appropriate biofluid for assessing their repletion in particular clinical contexts. [ABSTRACT FROM AUTHOR]

Plastid retrograde signaling plays a key role in coordinating the expression of plastid genes and photosynthesis-associated nuclear genes (PhANGs). Although plastid retrograde signaling can be substantially compromised by mitochondrial dysfunction, it is not yet clear whether specific mitochondrial factors are required to regulate plastid retrograde signaling. Here, we show that mitochondrial ATP synthase beta-subunit mutants with decreased ATP synthase activity are impaired in plastid retrograde signaling in Arabidopsis thaliana. Transcriptome analysis revealed that the expression levels of PhANGs were significantly higher in the mutants affected in the AT5G08670 gene encoding the mitochondrial ATP synthase beta-subunit, compared to wild-type (WT) seedlings when treated with lincomycin (LIN) or norflurazon (NF). Further studies indicated that the expression of nuclear genes involved in chloroplast and mitochondrial retrograde signaling was affected in the AT5G08670 mutant seedlings treated with LIN. These changes might be linked to the modulation of some transcription factors (TFs), such as LHY (Late Elongated Hypocotyl), PIF (Phytochrome-Interacting Factors), MYB, WRKY, and AP2/ERF (Ethylene Responsive Factors). These findings suggest that the activity of mitochondrial ATP synthase significantly influences plastid retrograde signaling.

Abstract Endothelial cells (ECs) angiogenesis is the process of sprouting new vessels from the existing ones, playing critical roles in physiological and pathological processes such as wound healing, placentation, ischemia/reperfusion, cardiovascular diseases and cancer metastasis. Although mitochondria are not the major sites of energy source in ECs, they function as important biosynthetic and signaling hubs to regulate ECs metabolism and adaptations to local environment, thus affecting ECs migration, proliferation and angiogenic process. The understanding of the importance and potential mechanisms of mitochondria in regulating ECs metabolism, function and the process of angiogenesis has developed in the past decades. Thus, in this review, we discuss the current understanding of mitochondrial proteins and signaling molecules in ECs metabolism, function and angiogeneic signaling, to provide new and therapeutic targets for treatment of diverse cardiovascular and angiogenesis-dependent diseases.

Protein posttranslational modifications are important factors that mediate the fine regulation of signaling molecules. O-linked β-N-acetylglucosamine-modification (O-GlcNAcylation) is a monosaccharide modification on N-acetylglucosamine linked to the hydroxyl terminus of serine and threonine of proteins. O-GlcNAcylation is responsive to cellular stress as a reversible and posttranslational modification of nuclear, mitochondrial and cytoplasmic proteins. Mitochondrial proteins are the main targets of O-GlcNAcylation and O-GlcNAcylation is a key regulator of mitochondrial homeostasis by directly regulating the mitochondrial proteome or protein activity and function. Disruption of O-GlcNAcylation is closely related to mitochondrial dysfunction. More importantly, the O-GlcNAcylation of cardiac proteins has been proven to be protective or harmful to cardiac function. Mitochondrial homeostasis is crucial for cardiac contractile function and myocardial cell metabolism, and the imbalance of mitochondrial homeostasis plays a crucial role in the pathogenesis of cardiovascular diseases (CVDs). In this review, we will focus on the interactions between protein O-GlcNAcylation and mitochondrial homeostasis and provide insights on the role of mitochondrial protein O-GlcNAcylation in CVDs.

Endothelial cells (ECs) angiogenesis is the process of sprouting new vessels from the existing ones, playing critical roles in physiological and pathological processes such as wound healing, placentation, ischemia/reperfusion, cardiovascular diseases and cancer metastasis. Although mitochondria are not the major sites of energy source in ECs, they function as important biosynthetic and signaling hubs to regulate ECs metabolism and adaptations to local environment, thus affecting ECs migration, proliferation and angiogenic process. The understanding of the importance and potential mechanisms of mitochondria in regulating ECs metabolism, function and the process of angiogenesis has developed in the past decades. Thus, in this review, we discuss the current understanding of mitochondrial proteins and signaling molecules in ECs metabolism, function and angiogeneic signaling, to provide new and therapeutic targets for treatment of diverse cardiovascular and angiogenesis-dependent diseases. [ABSTRACT FROM AUTHOR]

Significance: Mitochondrial proteins regulate the oxidative phosphorylation, cellular metabolism, and free radical generation. Redox modulation alters the mitochondrial proteins and instigates the damage to dopaminergic neurons. Toxicants contribute to Parkinson's disease (PD) pathogenesis in conjunction with aging and genetic factors. While oxidative modulation of a number of mitochondrial proteins is linked to xenobiotic exposure, little is known about its role in the toxicant-induced PD. Understanding the role of redox modulation of mitochondrial proteins in complex cellular events leading to neurodegeneration is highly relevant. Recent Advances: Many toxicants are shown to inhibit complex I or III and elicit free radical production that alters the redox status of mitochondrial proteins. Implication of redox modulation of the mitochondrial proteins makes them a target to comprehend the underlying mechanism of toxicant-induced PD. Critical Issues: Owing to multifactorial etiology, exploration of onset and progression and treatment outcomes needs a comprehensive approach. The article explains about a few mitochondrial proteins that undergo redox changes along with the promising strategies, which help to alleviate the toxicant-induced redox imbalance leading to neurodegeneration. Future Directions: Although mitochondrial proteins are linked to PD, their role in toxicant-induced parkinsonism is not yet completely known. Preservation of antioxidant defense machinery could alleviate the redox modulation of mitochondrial proteins. Targeted antioxidant delivery, use of metal chelators, and activation of nuclear factor erythroid 2-related factor 2, and combinational therapy that encounters multiple free radicals, could ameliorate the redox modulation of mitochondrial proteins and thereby PD progression. Antioxid. Redox Signal. 38, 824–852. [ABSTRACT FROM AUTHOR]

• The mitoPADdb stores mutations and qualitative expression variations of mitochondrial protein-encoding (MPE) genes associated with diseases. • It groups the diseases into 15 standard categories and links pathways, genes, and diseases. • The mitoPADdb compares quantitative transcript expression of MPE genes across diseases. • It can be a valuable resource for investigating mitochondrial dysfunction-related diseases and developing targeted therapy. Mitochondrial protein/gene mutations and expression variations contribute to the pathogenesis of various diseases, such as neurodegenerative and metabolic diseases. Detailed studies on mitochondrial protein-encoding (MPE) genes across diseases can provide clues for novel therapeutic strategies. Here, we collected, compiled, and manually curated the MPE gene mutation and expression variations data and their association with diseases in a single platform named mitoPADdb. The database contains 810 genes with 18,356 mutations and 1284 qualitative expression variations associated with 1793 diseases, grouped into 15 categories. It allows users to perform a comparative quantitative gene expression analysis for 317 transcriptomic studies across disease categories. Further, it provides information on MPE genes-associated molecular pathways. The mitoPADdb is a valuable resource for investigating mitochondrial dysfunction-related diseases. It can be accessed via http://bicresources.jcbose.ac.in/ssaha4/mitopaddb/index.html. [ABSTRACT FROM AUTHOR]

• Mitochondrial dysfunction is a major hallmark of aging. • Mitochondrial DNA may have mutations that affect lifespan. • The MitoAging project aims to find mutations that increase lifespan. • SNPs such as C5178A, G9055A, C8414T and A10398G may promote longevity. • Focusing on these SNPs may lead to preventive strategies and therapies that promote healthy aging. Mitochondrial dysfunction is a major hallmark of aging. Mitochondrial DNA (mtDNA) mutations (inherited or acquired) may cause a malfunction of the respiratory chain (RC), and thus negatively affect cell metabolism and function. In contrast, certain mtDNA single nucleotide polymorphisms (SNPs) may be beneficial to mitochondrial electron transport chain function and the extension of cellular health as well as lifespan. The goal of the MitoAging project is to detect key physiological characteristics and mechanisms that improve mitochondrial function and use them to develop therapies to increase longevity and a healthy lifespan. We chose to perform a systematic literature review (SLR) as a tool to collect key mtDNA SNPs associated with an increase in lifespan. Then validated our results by comparing them to the MitoMap database. Next, we assessed the effect of relevant SNPs on protein stability. A total of 28 SNPs were found in protein coding regions. These SNPs were reported in Japan, China, Turkey, and India. Among the studied SNPs, the C5178A mutation in the ND2 gene of Complex I of the RC was detected in all the reviewed reports except in Uygur Chinese centenarians. Then, we found that G9055A (ATP6 gene) and A10398G (ND3 gene) polymorphisms have been associated with a protective effect against Parkinson's disease (PD). Additionally, C8414T in ATP8 was significantly associated with longevity in three Japanese reports. Interestingly, using MitoMap we found that G9055A (ATP6 gene) was the only SNP promoting longevity not associated with any pathology. The identification of SNPs associated with an increase in lifespan opens the possibility to better understand individual differences regarding a decrease in illness susceptibility and find strategies that contribute to healthy aging. [ABSTRACT FROM AUTHOR]

Aging induces pathological cardiovascular changes such as cardiac dysfunction and arteriosclerosis. With aging, heart cells, especially, become more susceptible to lethal damage. In this report, we tried to understand the precise mechanism of myocardial change resulting from aging by examining the heart proteome in aging mice using two-dimensional gel electrophoresis (2DE). The proteins were stained with fluorescence dyes (SYPRO Ruby and Pro-Q Diamond) and identified by subsequent MALDI-TOF-MS / MS. As a result, markedly altered levels of 14 proteins and 7 phosphoproteins were detected in the hearts of 3-, 7-, 11-, and 20-month-old mice. The functions of these identified proteins and phosphoproteins were energy metabolism, muscle contraction, glycolysis, and cytoskeletal support. Additionally, the results of Western blotting confirmed changes in the expression of FTH, CPNE5, and SUCLA2. These findings showed that aging modified the expression of proteins and phosphoproteins in the heart. We suggest that changes in the expression of these proteins are critical to the development of cardiac dysfunction resulting from aging. J. Med. Invest. 69: 217-223, August, 2022. [ABSTRACT FROM AUTHOR]

The main aims in the development of a novel drug delivery vehicle is to efficiently carry therapeutic drugs in the body's circulatory system and successfully deliver them to the targeted site as needed to safely achieve the desired therapeutic effect. In the present study, a passive targeted functionalised nanocarrier was fabricated or wrapped the hollow mesoporous silica nanoparticles with 3-aminopropyl triethoxysilane (APTES) to prepare APTES-coated hollow mesoporous silica nanoparticles (HMSNAP). A nitrogen sorption analysis confirmed that the shape of hysteresis loops is altered, and subsequently the pore volume and pore diameters of GaC-HMSNAP was reduced by around 56 and 37%, respectively, when compared with HMSNAP. The physico-chemical characterisation studies of fabricated HMSNAP, Ga-HMSNAP and GaC-HMSNAP have confirmed their stability. The drug release capacity of the fabricated Ga-HMSNAP and GaC-HMSNAP for delivery of gallium and curcumin was evaluated in the phosphate buffered saline (pH 3.0, 6.0 and 7.4). In an in silico molecular docking study of the gallium-curcumin complex in PDI, calnexin, HSP60, PDK, caspase 9, Akt1 and PTEN were found to be strong binding. In vitro antitumor activity of both Ga-HMSNAP and GaC-HMSNAP treated MCF-7 cells was investigated in a dose and time-dependent manner. The IC50 values of GaC-HMSNAP (25 µM) were significantly reduced when compared with free gallium concentration (40 µM). The mechanism of gallium-mediated apoptosis was analyzed through western blotting and GaC-HMSNAP has increased caspases 9, 6, cleaved caspase 6, PARP, and GSK 3β(S9) in MCF-7 cells. Similarly, GaC-HMSNAP is reduced mitochondrial proteins such as prohibitin1, HSP60, and SOD1. The phosphorylation of oncogenic proteins such as Akt (S473), c-Raf (S249) PDK1 (S241) and induced cell death in MCF-7 cells. Furthermore, the findings revealed that Ga-HMSNAP and GaC-HMSNAP provide a controlled release of loaded gallium, curcumin and their complex. Altogether, our results depicted that GaC-HMNSAP induced cell death through the mitochondrial intrinsic cell death pathway, which could lead to novel therapeutic strategies for breast adenocarcinoma therapy. [ABSTRACT FROM AUTHOR]

Abstract Background The prediction of protein subcellular localization is a key step of the big effort towards protein functional annotation. Many computational methods exist to identify high-level protein subcellular compartments such as nucleus, cytoplasm or organelles. However, many organelles, like mitochondria, have their own internal compartmentalization. Knowing the precise location of a protein inside mitochondria is crucial for its accurate functional characterization. We recently developed DeepMito, a new method based on a 1-Dimensional Convolutional Neural Network (1D-CNN) architecture outperforming other similar approaches available in literature. Results Here, we explore the adoption of DeepMito for the large-scale annotation of four sub-mitochondrial localizations on mitochondrial proteomes of five different species, including human, mouse, fly, yeast and Arabidopsis thaliana. A significant fraction of the proteins from these organisms lacked experimental information about sub-mitochondrial localization. We adopted DeepMito to fill the gap, providing complete characterization of protein localization at sub-mitochondrial level for each protein of the five proteomes. Moreover, we identified novel mitochondrial proteins fishing on the set of proteins lacking any subcellular localization annotation using available state-of-the-art subcellular localization predictors. We finally performed additional functional characterization of proteins predicted by DeepMito as localized into the four different sub-mitochondrial compartments using both available experimental and predicted GO terms. All data generated in this study were collected into a database called DeepMitoDB (available at http://busca.biocomp.unibo.it/deepmitodb ), providing complete functional characterization of 4307 mitochondrial proteins from the five species. Conclusions DeepMitoDB offers a comprehensive view of mitochondrial proteins, including experimental and predicted fine-grain sub-cellular localization and annotated and predicted functional annotations. The database complements other similar resources providing characterization of new proteins. Furthermore, it is also unique in including localization information at the sub-mitochondrial level. For this reason, we believe that DeepMitoDB can be a valuable resource for mitochondrial research.

The main aims in the development of a novel drug delivery vehicle is to efficiently carry therapeutic drugs in the body’s circulatory system and successfully deliver them to the targeted site as needed to safely achieve the desired therapeutic effect. In the present study, a passive targeted functionalised nanocarrier was fabricated or wrapped the hollow mesoporous silica nanoparticles with 3-aminopropyl triethoxysilane (APTES) to prepare APTES-coated hollow mesoporous silica nanoparticles (HMSNAP). A nitrogen sorption analysis confirmed that the shape of hysteresis loops is altered, and subsequently the pore volume and pore diameters of GaC-HMSNAP was reduced by around 56 and 37%, respectively, when compared with HMSNAP. The physico-chemical characterisation studies of fabricated HMSNAP, Ga-HMSNAP and GaC-HMSNAP have confirmed their stability. The drug release capacity of the fabricated Ga-HMSNAP and GaC-HMSNAP for delivery of gallium and curcumin was evaluated in the phosphate buffered saline (pH 3.0, 6.0 and 7.4). In an in silico molecular docking study of the gallium-curcumin complex in PDI, calnexin, HSP60, PDK, caspase 9, Akt1 and PTEN were found to be strong binding. In vitro antitumor activity of both Ga-HMSNAP and GaC-HMSNAP treated MCF-7 cells was investigated in a dose and time-dependent manner. The IC50 values of GaC-HMSNAP (25 µM) were significantly reduced when compared with free gallium concentration (40 µM). The mechanism of gallium-mediated apoptosis was analyzed through western blotting and GaC-HMSNAP has increased caspases 9, 6, cleaved caspase 6, PARP, and GSK 3β(S9) in MCF-7 cells. Similarly, GaC-HMSNAP is reduced mitochondrial proteins such as prohibitin1, HSP60, and SOD1. The phosphorylation of oncogenic proteins such as Akt (S473), c-Raf (S249) PDK1 (S241) and induced cell death in MCF-7 cells. Furthermore, the findings revealed that Ga-HMSNAP and GaC-HMSNAP provide a controlled release of loaded gallium, curcumin and their complex. Altogether, our results depicted that GaC-HMNSAP induced cell death through the mitochondrial intrinsic cell death pathway, which could lead to novel therapeutic strategies for breast adenocarcinoma therapy.

An increasing number of studies point to an association between mitochondrial proteins (MPs) and lung cancer (LC). However, the causal relationship between MPs and LC remains unclear. Consequently, our study employed a bidirectional Mendelian randomization (MR) analysis to explore the causal association between MPs and different pathological types of LC. A two-sample MR study was performed using the genome-wide association study (GWAS) data publicly available. We applied the primary inverse variance weighted (IVW) method along with additional MR methods to validate the causality between MPs and different pathological types of LC. To ensure the robustness of our findings, sensitivity analyses were employed. Moreover, we performed a bi-directional MR analysis to determine the direction of the causal association. We identified a total of seven MPs had significant causal relationships on overall LC, lung squamous cell carcinoma (LUSC), and small cell lung carcinoma (SCLC). We found two MPs had significant associations with overall LC, four MPs had significant associations with LUSC, and four MPs had significant associations with SCLC. Additionally, an MP was found to have a nominal relationship with LUSC. Moreover, no causality was found between MPs and lung adenocarcinoma (LUAD). Bidirectional MR showed no reverse effect between identified MPs and different pathological types of LC. In general, our findings of this MR study suggest causal associations of specific MPs with overall LC, LUSC, and SCLC. However, no such causality was found in LUAD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ji, Lv, Liu, Han, Yuan and Gu.)

Alzheimer’s disease (AD) is the most common type of dementia. Amyloid β (Aβ) plaques, tau-containing neurofibrillary tangles, and neuronal loss leading to brain atrophy are pathologic hallmarks of AD. Given the importance of early diagnosis, extensive efforts have been undertaken to identify diagnostic and prognostic biomarkers for AD. Circulating extracellular vesicles (EVs) provide a platform for “liquid biopsy” biomarkers for AD. Here, we characterized the RNA contents of plasma EVs of age-matched individuals who were cognitively normal (healthy controls (HC)) or had mild cognitive impairment (MCI) due to AD or had mild AD dementia (AD). Using RNA sequencing analysis, we found that mitochondrial (mt)-RNAs, including MT-ND1-6 mRNAs and other protein-coding and non-coding mt-RNAs, were strikingly elevated in plasma EVs of MCI and AD individuals compared with HC. EVs secreted from cultured astrocytes, microglia, and neurons after exposure to toxic conditions relevant to AD pathogenesis (Aβ aggregates and H2O2), contained mitochondrial structures (detected by electron microscopy) and mitochondrial RNA and protein. We propose that in the AD brain, toxicity-causing mitochondrial damage results in the packaging of mitochondrial components for export in EVs and further propose that mt-RNAs in plasma EVs can be diagnostic and prognostic biomarkers for MCI and AD.

Mutation in the human MPV17 gene or the functional yeast orthologue SYM1 result in mitochondrial DNA depletion. MPV17 homologs are also found in plants including Arabidopsis, but the function of these genes remain unclear. Arabidopsis genome contains 10 MPV17 homologs. Among these, the AtMPV17 protein was localized in mitochondria as MPV17 and SYM1. The yeast sym1 knock out mutant cannot grow on ethanol-containing medium at 37 °C. AtMPV17 complements the ethanol growth defection of sym1 yeast MPV17 ortholog cells at 37 °C, suggesting that AtMPV17 is a functional ortholog of SYM1. AtMPV17 knock out mutant, atmpv17 show similar growth and seed development to those of the wild-type plant on normal growth condition. However, atmpv17 mutant is more sensitive to ABA and mannitol during germination and seedling growth than wild type plants. Growth retardation of the atmpv17 knock out mutant on medium containing ABA and mannitol is complemented by AtMPV17 overexpression. These results suggest that the AtMPV17 contributes to osmotic stress tolerance in plants. [ABSTRACT FROM AUTHOR]

Key points: Endurance‐type training with blood flow restriction (BFR) increases maximum oxygen uptake (V̇O2max) and exercise endurance of humans. However, the physiological mechanisms behind this phenomenon remain uncertain.In the present study, we show that BFR‐interval training reduces the peripheral resistance to oxygen transport during dynamic, submaximal exercise in recreationally‐trained men, mainly by increasing convective oxygen delivery to contracting muscles.Accordingly, BFR‐training increased oxygen uptake by, and concomitantly reduced net lactate release from, the contracting muscles during relative‐intensity‐matched exercise, at the same time as invoking a similar increase in diffusional oxygen conductance compared to the training control.Only BFR‐training increased resting femoral artery diameter, whereas increases in oxygen transport and uptake were dissociated from changes in the skeletal muscle content of mitochondrial electron‐transport proteins.Thus, physically trained men benefit from BFR‐interval training by increasing leg convective oxygen transport and reducing lactate release, thereby improving the potential for increasing the percentage of V̇O2max that can be sustained throughout exercise. In the present study, we investigated the effect of training with blood flow restriction (BFR) on thigh oxygen transport and uptake, and lactate release, during exercise. Ten recreationally‐trained men (50 ± 5 mL kg−1 min−1) completed 6 weeks of interval cycling with one leg under BFR (BFR‐leg; pressure: ∼180 mmHg) and the other leg without BFR (CON‐leg). Before and after the training intervention (INT), thigh oxygen delivery, extraction, uptake, diffusion capacity and lactate release were determined during knee‐extensor exercise at 25% incremental peak power output (iPPO) (Ex1), followed by exercise to exhaustion at 90% pre‐training iPPO (Ex2), by measurement of femoral‐artery blood flow and femoral‐arterial and ‐venous blood sampling. A muscle biopsy was obtained from legs before and after INT to determine mitochondrial electron‐transport protein content. Femoral‐artery diameter was also measured. In the BFR‐leg, after INT, oxygen delivery and uptake were higher, and net lactate release was lower, during Ex1 (vs. CON‐leg; P < 0.05), with an 11% larger increase in workload (vs. CON‐leg; P < 0.05). During Ex2, after INT, oxygen delivery was higher, and oxygen extraction was lower, in the BFR‐leg compared to the CON‐leg (P < 0.05), resulting in an unaltered oxygen uptake (vs. CON‐leg; P > 0.05). In the CON‐leg, at both intensities, oxygen delivery, extraction, uptake and lactate release remained unchanged (P > 0.05). Resting femoral artery diameter increased with INT only in the BFR‐leg (∼4%; P < 0.05). Oxygen diffusion capacity was similarly raised in legs (P < 0.05). Mitochondrial protein content remained unchanged in legs (P > 0.05). Thus, BFR‐interval training enhances oxygen utilization by, and lowers lactate release from, submaximally‐exercising muscles of recreationally‐trained men mainly by increasing leg convective oxygen transport. Key points: Endurance‐type training with blood flow restriction (BFR) increases maximum oxygen uptake (V̇O2max) and exercise endurance of humans. However, the physiological mechanisms behind this phenomenon remain uncertain.In the present study, we show that BFR‐interval training reduces the peripheral resistance to oxygen transport during dynamic, submaximal exercise in recreationally‐trained men, mainly by increasing convective oxygen delivery to contracting muscles.Accordingly, BFR‐training increased oxygen uptake by, and concomitantly reduced net lactate release from, the contracting muscles during relative‐intensity‐matched exercise, at the same time as invoking a similar increase in diffusional oxygen conductance compared to the training control.Only BFR‐training increased resting femoral artery diameter, whereas increases in oxygen transport and uptake were dissociated from changes in the skeletal muscle content of mitochondrial electron‐transport proteins.Thus, physically trained men benefit from BFR‐interval training by increasing leg convective oxygen transport and reducing lactate release, thereby improving the potential for increasing the percentage of V̇O2max that can be sustained throughout exercise. [ABSTRACT FROM AUTHOR]

Mitochondrial dysfunctions and oxidative stress play important roles in the early pathogenesis of Alzheimer's disease (AD), which also involves the aberrant expression levels of mitochondrial proteins. However, the molecular mechanisms underlying the aberrant expression levels of these proteins in the pathogenesis of AD are still not completely understood. Tid1 (DnaJA3/mtHsp40), a mammalian homolog of the Drosophila tumor suppressor Tid56, is reported to induce mitochondrial fragmentation associated with an increase in reactive oxygen species (ROS) levels, resulting in cell death in some cancer cells. However, the involvement of Tid1 in AD pathogenesis is as yet unknown. In this study, we found that the Tid1 protein levels were upregulated in the hippocampus of AD patients and Tg2576 mice. Our in vitro studies showed that Aβ42 increased the expression levels of Tid1 in primary rat cortical neurons. The knockdown of Tid1 protected against neuronal cell death induced by Aβ42, and Tid1-mediated neuronal cell death, was dependent on the increased ROS generation and caspase-3 activity. The overexpression of Tid1 in HEK293-APP cells increased the BACE1 levels, resulting in increased Aβ production. Conversely, Tid1 knockdown in HEK293-APP cells and primary cultured neurons decreased Aβ production through the reduction in the BACE1 levels. We also found that the overexpression of Tid1 activated c-Jun N-terminal kinase (JNK) leading to increased Aβ production. Taken together, our results suggest that upregulated Tid1 levels in the hippocampus of patients with AD and Tg2576 mice induce apoptosis and increase Aβ production, and Tid1 may therefore be a suitable target in therapeutic interventions for AD. [ABSTRACT FROM AUTHOR]

Mitochondria fulfil essential functions in respiration and metabolism as well as regulating stress responses and apoptosis. Most native mitochondrial proteins are encoded by nuclear genes and are imported into mitochondria via one of several receptors that recognize N-terminal signal peptides. The targeting of recombinant proteins to mitochondria therefore requires the presence of an appropriate N-terminal peptide, but little is known about mitochondrial import in monocotyledonous plants such as rice (Oryza sativa). To gain insight into this phenomenon, we targeted nuclear-encoded enhanced green fluorescent protein (eGFP) to rice mitochondria using six mitochondrial pre-sequences with diverse phylogenetic origins, and investigated their effectiveness by immunoblot analysis as well as confocal and electron microscopy. We found that the ATPA and COX4 (Saccharomyces cerevisiae), SU9 (Neurospora crassa), pFA (Arabidopsis thaliana) and OsSCSb (Oryza sativa) peptides successfully directed most of the eGFP to the mitochondria, whereas the MTS2 peptide (Nicotiana plumbaginifolia) showed little or no evidence of targeting ability even though it is a native plant sequence. Our data therefore indicate that the presence of particular recognition motifs may be required for mitochondrial targeting, whereas the phylogenetic origin of the pre-sequences probably does not play a key role in the success of mitochondrial targeting in dedifferentiated rice callus and plants. [ABSTRACT FROM AUTHOR]

The purpose of this work was to identify the gene defect underlying a relatively mild rod-cone dystrophy (RCD), lacking disease-causing variants in known genes implicated in inherited retinal disorders (IRD), and provide transcriptomic and immunolocalization data to highlight the best candidate. The DNA of the female patient originating from a consanguineous family revealed no large duplication or deletion, but several large homozygous regions. In one of these, a homozygous frameshift variant, c.244_246delins17 p.(Trp82Valfs*4); predicted to lead to a nonfunctional protein, was identified in CCDC51. CCDC51 encodes the mitochondrial coiled-coil domain containing 51 protein, also called MITOK. MITOK ablation causes mitochondrial dysfunction. Here we show for the first time that CCDC51/MITOK localizes in the retina and more specifically in the inner segments of the photoreceptors, well known to contain mitochondria. Mitochondrial proteins have previously been implicated in IRD, although usually in association with syndromic disease, unlike our present case. Together, our findings add another ultra-rare mutation implicated in non-syndromic IRD, whose pathogenic mechanism in the retina needs to be further elucidated.

Background: Lung cancer is a highly aggressive cancer with a poor prognosis and is associated with distant metastasis; however, there are no clinically recognized biomarkers for the early diagnosis and prediction of lung cancer metastasis. We sought to identify the differential mitochondrial protein profiles and understand the molecular mechanisms governing lung cancer metastasis. Methods: Mitochondrial proteomic analysis was performed to screen and identify the differential mitochondrial protein profiles between human large cell lung cancer cell lines with high (L‐9981) and low (NL‐9980) metastatic potential by two‐dimensional differential gel electrophoresis. Western blot was used to validate the differential mitochondrial proteins from the two cells. Bioinformatic proteome analysis was performed using the Mascot search engine and messenger RNA expression of the 37 genes of the differential mitochondrial proteins were detected by real‐time PCR. Results: Two hundred and seventeen mitochondrial proteins were differentially expressed between L‐9981 and NL‐9980 cells (P < 0.05). Sixty‐four analyzed proteins were identified by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry coupled with database interrogation. Ontology analysis revealed that these proteins were mainly involved in the regulation of translation, amino acid metabolism, tricarboxylic acid cycle, cancer invasion and metastasis, oxidative phosphorylation, intracellular signaling pathway, cell cycle, and apoptosis. Conclusion: Our results suggest that the incorporation of more samples and new datasets will permit the definition of a collection of proteins as potential biomarkers for the prediction and diagnosis of lung cancer metastasis. [ABSTRACT FROM AUTHOR]

Vigorous activation of mitochondria in spermatozoa during capacitation induces the biological and morphological changes of spermatozoa to acquire fertilizing ability. To in-depth understand the dynamic roles of mitochondrial and male fertility, this study was to identify how the mitochondrial proteins are changed during sperm capacitation and regulate male fertility using boar spermatozoa. The mitochondrial proteins were differentially changed during sperm capacitation according to fertility status, i.e., superior litter size (SL) and normal litter size (NL). Following sperm capacitation, ubiquitin-cytochrome c reductase core protein (UQCRC1) and ATP synthase F1 (ATP5F1) increased in NL, while cytochrome c oxidase subunit 5B (COX5B), and cytochrome c 1 (CYC1) proteins decreased. In contrast, only and ubiquinone oxidoreductase core subunit 8 (NDUFS8) protein was increased in SL following capacitation. The protein expression difference value of CYC1, COX5B, and NDUFS8 following sperm capacitation was lower in NL than SL boars. Based on these complicated changes during sperm capacitation, the accuracy for predicting male fertility of NDUFS8 was increased to 87 %. Overall, considering the systematic orchestration of mitochondrial protein expression according to sperm capacitation status, it will be possible to better understand male fertility. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Small cell lung cancer (SCLC) is highly aggressive and is associated with a dismal prognosis. However, there are no clinically recognized biomarkers for early diagnosis. In this study, we used quantitative proteomics to build differential mitochondrial protein profiles that may be used for early diagnosis and investigated the pathogenesis of lung cancer. Methods: We cultured SCLC cells (NCI‐H446) and normal human bronchial epithelial cells (16‐HBE); mitochondria were extracted and purified using differential and Percoll density gradient centrifugation. Subsequently, we used Western blot analysis to validate mitochondrial purity and labeled proteins/peptides from NCI‐H446 and 16‐HBE cells using relative and absolute quantification of ectopic tags. We then analyzed mixed samples and identified proteins using two‐dimensional liquid chromatography‐tandem mass spectrometry. Additionally, we performed subsequent bioinformatic proteome analyses using the programs ExPASy, GOA, and STRING. Finally, the relationship between ornithine aminotransferase expression and clinicopathological features in lung cancer patients was evaluated using immunohistochemistry. Results: One hundred and fifty‐three mitochondrial proteins were differentially expressed between 16‐HBE and NCI‐H446 cells. The expression of 30 proteins between 16‐HBE and NCI‐H446 cells increased more than 1.3‐fold. The upregulation of ornithine aminotransferase was associated with pathological grade and clinical tumor node metastasis stage. Conclusion: Our experiment represented a promising method for building differential mitochondrial protein profiles between NCI‐H446 and 16‐HBE cells. Such analysis may also help to identify novel biomarkers of lung cancer. [ABSTRACT FROM AUTHOR]

Highlights • Epoxyeicosatrienoic acids (EETs), specifically 11,12- and 14,15-EETs, reduce adipogenesis in human mesenchymal stem cells and mouse preadipocytes (3T-3L1). • EETs and heme-oxygenase 1 (HO-1) form a synergistic, functional module whose effects on adipocyte and vascular function is greater than the effects of sEH deletion alone. • Targeting sEH regulates EET and attenuates obesity. Abstract We have shown that epoxyeicosatrienoic acids (EETs), specifically 11,12- and 14,15-EETs, reduce adipogenesis in human mesenchymal stem cells and mouse preadipocytes (3T-3L1). In this study, we explore the effects of soluble epoxide hydrolase (sEH) deletion on various aspects of adipocyte-function, including programing for white vs. beige-like fat, and mitochondrial and thermogenic gene-expressions. We further hypothesize that EETs and heme-oxygenase 1 (HO-1) form a synergistic, functional module whose effects on adipocyte and vascular function is greater than the effects of sEH deletion alone. In in vitro studies, we examined the effect of sEH inhibitors on MSC-derived adipocytes. MSC-derived adipocytes exposed to AUDA, an inhibitor of sEH, exhibit an increased number of small and healthy adipocytes, an effect reproduced by siRNA for sEH. in vivo studies indicate that sEH deletion results in a significant decrease in adipocyte size, inflammatory adipokines NOV, TNFα, while increasing adiponectin (p < 0.05). These findings are associated with a decrease in body weight (p < 0.05), and visceral fat (p < 0.05). Importantly, sEH deletion was associated with a significant increase in Mfn1, COX 1, UCP1 and adiponectin (p < 0.03). sEH deletion was manifested by a significant increase in EETs isomers 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET and an increased EETs/DHETEs ratio. Notably, activation of HO-1 gene expression further increased the levels of EETs, suggesting that the antioxidant HO-1 system protects EETs from degradation by ROS. These results are novel in that sEH deletion, while increasing EET levels, resulted in reprograming of white fat to express mitochondrial and thermogenic genes, a phenotype characteristic of beige-fat. Thus, EETs agonist(s) and sEH inhibitors may have therapeutic potential in the treatment of metabolic syndrome and obesity. [ABSTRACT FROM AUTHOR]