Search Results (144)

Pregnancy-associated hemodynamic overload and hormonal changes induce hypertrophy and metabolic remodeling of the maternal heart. Mitochondrial motility, mediated by ras homolog family member T (RHOT) 1 and RHOT2, is essential for cardiac adaptation to increased workload, cardiomyocyte hypertrophy, and sarcomere maturation. To test the hypothesis that Rhot1/2 expression is required for pregnancy- and postpartum-associated adaptations of the maternal heart, female mice with tamoxifen-inducible, cardiomyocyte-selective deletion of Rhot1 and Rhot2 (iRhot1/2-KO) were mated. Following gene deletion in adult mice, cardiac tissue and function were analyzed after three to five successive pregnancies and postpartum nursing periods. Age-matched nulliparous iRhot1/2-KO mice and age-matched mice expressing Rhot1 and Rhot2 served as controls. Motility of mitochondria isolated from iRhot1/2-KO hearts was impaired, as determined by the number of mobile mitochondria in an in vitro motor protein-driven single mitochondrion motility assay performed on surface-immobilized microtubules. Despite loss of Rhot1/2 expression, contractile function assessed by transthoracic echocardiography, mRNA expression of peripartum-associated heart failure markers, cardiac structure, mitochondrial morphology, mitochondrial enzymatic activity, and mitochondrial DNA content were all comparable to controls expressing Rhot1/2 at the investigated time points. RNA sequencing-based gene profiling identified a transcriptional program through which RHOT proteins preserve cardiac energetic and contraction gene expression during pregnancy and postpartum. Together, cardiomyocyte-selective loss of Rhot1/2 expression in the adult heart does not cause peripartum-associated heart failure, despite reduced cardiac energetic and contraction gene expression. Full article

To explore the molecular basis of hypoxia tolerance variation within euteleosts, we compared the hypoxia-inducible factor (HIF) pathways of the highly tolerant Nile tilapia (Oreochromis niloticus) and the hypoxia-sensitive rainbow trout (Oncorhynchus mykiss). Evolutionary analysis revealed that Nile tilapia possesses single copies of Hif-1α and prolyl hydroxylase domain protein 2 (Phd2), whereas rainbow trout retains two and three copies, respectively. The Leu-X-X-Leu-Ala-Pro (LXXLAP) motifs in the oxygen-dependent degradation (ODD) domain of Hif-1α and the interacting loop region of Phd2 are highly conserved, indicating a conserved core mechanism for regulating Hif-1α stability. However, differences in charged residue composition flanking the Phd2 loop (e.g., fewer positively charged residues in Nile tilapia) were identified. Molecular dynamics simulations revealed that the complex formed by Nile tilapia Phd2 and the Hif-1α LXXLAP motif was unstable across physiological temperatures, suggesting potential impairment of the catalytic geometry compatible with hydroxylation and elevated normoxic Hif-1α stability. In contrast, the corresponding complexes in rainbow trout were more stable, particularly at low temperatures. Expression profiling revealed that Nile tilapia tissues, including the heart, maintain higher basal expression of glycolytic genes, may help support energy production during hypoxia. Our findings indicate that a weakened protein interaction and high constitutive expression is predicted to enhance HIF pathway responsiveness, potentially priming vital tissues for glycolytic energy production and may contribute to this species’ hypoxia tolerance. Full article

Precise control of mitochondrial electron transport is essential to maintain mitochondrial coupling and efficiency in ATP production. Furthermore, disruptions to ETC complex function can drive increased oxidant production, resulting in oxidative damage to the mitochondrion and bioenergetic inefficiency. This is highly relevant in the aging heart, as increased cardiac oxidative stress and mitochondrial dysfunction are hallmarks of age-related cardiovascular disease. Lysine acetylation has recently been characterized as a novel regulator of mitochondrial metabolic and bioenergetic function in the aging heart. In the present study, we investigated how lysine acetylation regulates oxidant production and redox milieu through mitochondrial acetyltransferase GCN5L1. Using a cardiac-specific GCN5L1 knockout mouse model, we observed that age-associated lipid peroxidation and semiquinone radicals were decreased with GCN5L1 KO. RNA sequencing analysis identified mitochondrial bioenergetic and respiratory pathways revolving around the respiratory chain to be enriched in the old KO group. Further, we showed the old KO group to exhibit reduced acetylation of ETC complex and antioxidant proteins, improved ETC complex and antioxidant protein activity. Overall, GCN5L1 regulates redox homeostasis in the aged heart by regulating mitochondrial ETC complex activity, oxidative stress, and mitochondrial bioenergetics. These findings identify GCN5L1 and acetylation as potential therapeutic targets in aging and age-related diseases. Full article

Background: Hemiboea yongfuensis is a recently discovered critically endangered species. It is exclusive to the limestone regions of Yongfu County, Guilin, Guangxi. Currently, there is a lack of mitogenome data for Hemiboea species, hindering the potential of disclosing the evolutionary processes of the mitochondrial genome, which has been far less assembled and shown to be complex in the plant kingdom. Moreover, it prevents potential applications of mitochondrial genome data in phylogenetics and plant adaption, breeding, and conservation. Results: In order to reveal the mitochondrial features and variations and explore the usefulness of mitochondrial genes in phylogenetics, in this study, we assembled the complete mitogenome of H. yongfuensis using PacBio HiFi long reads, and analyzed its codon usage bias, RNA editing sites, repetitive sequences, sequence lateral transfer, phylogenetic relationships, and synteny. The linear mitochondrial genome assembly we obtained has a length of 619,997 bp and a GC content of 43.63%. The assembly encompasses 61 genes, which include 37 protein-coding genes (PCGs), 21 transfer RNA (tRNA) genes, and 3 ribosomal RNA (rRNA) genes. Importantly, our analysis uncovered a significant presence of repetitive sequences with a high proportion of forward repeats in the mitogenome and significant transposition of sequences from the chloroplast to mitochondrion. Additionally, we revealed the codon usage characteristics of protein-coding genes and identified numerous RNA editing events. Furthermore, we assessed the collinearity of the species in the Gesneriaceae family and found rampant reorganizations. The phylogenetic analyses based on the mitochondrial PCGs for the entire Lamiales order show the monophyly of Gesneriaceae as well as other families and a general high phylogenetic resolution. Conclusions: Our study provides the first mitogenome data for H. yongfuensis and the genus Hemiboea, expanding the rapidly increasing but yet limited plant mitogenome resources. It enhances our understanding of the mitogenome and Lamiales evolution, whereas more potentials of the mitogenome data, such as its possible functions in adaptation to limestone habitats, conservation, and germplasm breeding, remain under-exploited. This first reported Hemiboea mitogenome in addition to more mitogenomes from the same and related species would shed further light on these unresolved issues in future studies. Full article

Background: The apicomplexan parasite Toxoplasma gondii causes serious diseases in animals and humans. The in vitro efficacy of the antimicrobial peptide mixture tyrothricin, composed of tyrocidines and gramicidins, against T. gondii tachyzoites was investigated. Methods: Effects against T. gondii were determined by monitoring inhibition of tachyzoite proliferation and electron microscopy, host cell and splenocyte toxicity was measured by Alamar blue assay, and early embryo toxicity was assessed using zebrafish embryos. Differential affinity chromatography coupled to mass spectrometry and proteomics (DAC-MS-proteomics) was employed to identify potential molecular targets in T. gondii cell-free extracts. Results: Tyrothricin inhibited T. gondii proliferation at IC₅₀s < 100 nM, with tyrocidine A being the active and gramicidin A the inactive component. Tyrothricin also impaired fibroblast, T cell and zebrafish embryo viability at 1 µM. Electron microscopy carried out after 6 h of treatment revealed cytoplasmic vacuolization and structural alterations in the parasite mitochondrion, but these changes appeared only transiently, and tachyzoites recovered after 96 h. Tyrothricin also induced a reduction in the mitochondrial membrane potential. DAC-MS-proteomics identified 521 proteins binding only to tyrocidine A. No specific binding to gramicidin A was noted, and four proteins were common to both peptides. Among the proteins binding specifically to tyrocidine A were several SRS surface antigens and secretory proteins, mitochondrial inner and outer membrane proteins associated with the electron transfer chain and porin, and several calcium-binding proteins putatively involved in signaling. Discussion: These results suggest that tyrocidine A potentially affected multiple pathways important for parasite survival and development. Full article

The increasing threat of zoonotic malaria parasites of humans, such as Plasmodium knowlesi, make the search for improved pharmacotherapy imperative. Using protein sequence and structural analyses, phylogenetics, protein network mapping, protein–ligand interaction, and small molecule docking studies, we have identified for the first time the predicted structure, function, and druggability of the P. knowlesi heat shock protein 90s (PkHsp90s). Four isoforms were identified (in the cytosol, endoplasmic reticulum, mitochondrion, and apicoplast), and key structural differences were elucidated compared to human Hsp90s. In particular, the glycine-rich helix loop (GHL) motif of cytosolic PkHsp90 was predicted to have a straight conformation that forms a plasmodial-specific hydrophobic extension of the lid domain of the ATP-binding site, which was not observed for the cytosolic human Hsp90s, HSPC1 (Hsp90α), and HSPC3 (Hsp90β). Virtual screening identified for the first time a number of compounds from the ZINC database (ZINC22007970, ZINC724661072, and ZINC724661078) that were predicted to bind strongly to the GHL-associated pocket of PkHsp90, with weak or no binding to HSPC1. This study has provided a molecular framework in support of rational drug design, targeting PkHsp90s as a promising route for antimalarial drug development in the fight against zoonotic malaria. Full article

Malaria remains a major global health threat, particularly in low- and middle-income countries, where children under five and pregnant women are most vulnerable. Despite notable progress in reducing malaria-related morbidity and mortality, the rise of drug-resistant Plasmodium falciparum strains continues to undermine eradication efforts. In this context, the parasite’s mitochondrion has emerged as a promising target for novel antimalarial therapies due to its essential role in parasite viability throughout all life cycle stages and its marked structural and biochemical differences from the human counterpart. This review highlights recent advances in the development of compounds targeting mitochondrial function in P. falciparum and discusses the utility of Saccharomyces cerevisiae as a powerful model organism for antimalarial drug discovery. Owing to its shared eukaryotic features, genetic tractability, and capacity for heterologous expression of parasite mitochondrial proteins, S. cerevisiae offers a cost-effective and experimentally accessible platform for elucidating drug mechanisms and accelerating therapeutic development. Full article

Paeonia ludlowii, a critically endangered species endemic to Tibet, China, possesses significant ornamental, culinary, and medicinal value. However, its mitochondrial genome remains understudied, limiting insights into its evolutionary mechanisms and constraining conservation genetics applications and molecular breeding programs. We present the first complete assembly and comprehensive analysis of the P. ludlowii mitochondrial genome. Most remarkably, we discovered that the P. ludlowii mitogenome exhibits an atypical dual-circular structure, representing the first documented occurrence of this architectural feature within the genus Paeonia. The assembled genome spans 314,371 bp and encodes 42 tRNA genes, 3 rRNA genes, and 31 protein-coding genes, with a pronounced adenine–thymine bias. This multipartite genome structure is characterized by abundant repetitive elements (112 functionally annotated SSRs, 33 tandem repeats, and 945 dispersed repeats), which potentially drive genome rearrangements and facilitate adaptive evolution. Analyses of codon usage bias and nucleotide diversity revealed highly conserved gene expression regulation with limited variability. Phylogenetic reconstruction confirms that P. ludlowii, P. suffruticosa, and P. lactiflora form a monophyletic clade, reflecting close evolutionary relationships, while extensive syntenic collinearity with other Paeonia species underscores mitochondrial genome conservation at the genus level. Extensive inter-organellar gene transfer events, particularly from chloroplast to mitochondrion, suggest that such DNA exchanges enhance genetic diversity and promote environmental adaptation. The discovery of the dual-circular architecture provides novel insights into plant mitochondrial genome evolution and structural plasticity. This study elucidates the unique structural characteristics of the P. ludlowii mitochondrial genome and establishes a crucial genetic foundation for developing targeted conservation strategies and facilitating molecular-assisted breeding programs for this endangered species. Full article

Toxoplasma gondii is an Apicomplexan parasite that possesses a well-developed system of scavengers of reactive oxygen species (ROS). Among its components, T. gondii mitochondrial superoxide dismutase (TgSOD2) is essential, as predicted by the CRISPR phenotype index and evidenced by the non-viability of its constitutive knockouts. As an obligate intracellular parasite, TgSOD2 is upregulated during extracellular stages. Herein, we generated a viable TgSOD2 knockdown mutant using an inducible auxin–degron system to explore the biological role of TgSOD2 in T. gondii. Depletion of TgSOD2 led to impaired parasite growth and replication, reduced mitochondrial membrane potential (MMP), abnormalities in the distribution of ATP synthase within its mitochondrial electron transport chain (mETC), and increased susceptibility to mETC inhibitors. Through a proximal biotinylation approach, we identified the interactions of TgSOD2 with complexes IV and V of its mETC, suggesting that these sites are sensitive to ROS. Our study provides the first insights into the role of TgSOD2 in maintaining its mitochondrial redox homeostasis and subsequent parasite replication fitness. Significance: Toxoplasma gondii infects nearly a third of the world population and can cause fetal miscarriages or life-threatening complications in vulnerable patients. Current therapies do not eradicate the parasite from the human hosts, rendering them at risk of recurrence during their lifetimes. T. gondii has a single mitochondrion, which is well-known for its susceptibility to oxidative damage that leads to T. gondii’s death. Therefore, targeting T. gondii mitochondrion remains an attractive therapeutic strategy for drug development. T. gondii’s mitochondrial superoxide dismutase is an antioxidant protein in the parasite mitochondrion and is essential for its survival. Understanding its biological role could reveal mitochondrial vulnerabilities in T. gondii and provide new leads for the development of effective treatments for T. gondii infections. Full article

Symbiotic interactions between legumes and a group of soil bacteria, known as rhizobia, lead to the formation of a specialized organs called root nodules. Inside them, atmospheric nitrogen (N₂) is fixed by bacteria and reduced to forms available to plants, catalyzed by the nitrogenase enzyme complex. The development of a symbiotic relationship between legumes and nodule bacteria is a multi-stage, precisely regulated process, characterized by a high specificity of partner selection. Nodulation involves the enhanced expression of certain plant genes, referred to as early- and late-nodulin genes. Many nodulin genes encode hydroxyproline-rich glycoproteins (HRGPs) and proline-rich proteins (PRPs) which are involved in various processes, including infection thread formation, cell signaling, and defense responses, thereby affecting nodule formation and function. Cyclophilins (CyPs) belong to a family of proteins with peptidyl-prolyl cis–trans isomerase activity. Proteins with cyclophilin domain can be found in the cytoplasm, endoplasmic reticulum, nucleus, chloroplast, and mitochondrion. They are involved in various processes, such as protein folding, cellular signaling, mRNA maturation, and response to biotic and abiotic stress. In this review, we aim to summarize the molecular processes involved in the development of symbiosis and highlight the potential role of cyclophilins (peptidyl-prolyl cis-trans isomerases) in this process. Full article

To explore the molecular mechanism of aerobic exercise to improve heart failure and to provide a theoretical basis and experimental reference for the treatment of heart failure. Nine-week-old male mice were used to establish a left ventricular pressure overload-induced heart failure model by transverse aortic constriction (TAC). The mice were randomly divided into four groups: a sham group (SHAM), heart failure group (HF), heart failure + SKQ1 group (HS) and heart failure + aerobic exercise group (HE). The mice in the HE group were subjected to moderate-intensity aerobic exercise interventions. The mitochondrion-targeting antioxidant (SKQ1) contains the lipophilic cation TPP, which targets scavenging mitochondrial ROS. The HS group was subjected to SKQ1 (100 nmol/kg/d) interventions, which were initiated 1 week after the surgery, and the interventions lasted 8 weeks. Cardiac function was assessed by ultrasound, cardiomyocyte size by H&E and WGA staining, myocardial fibrosis by Masson’s staining, and myocardial tissue oxidative stress and apoptosis by DHE and TUNEL fluorescence staining, respectively. Western blotting was used to detect the expression of mitochondrial quality control, inflammation, and apoptosis-related proteins. In the cellular level, an in vitro cellular model was established by isolating primary cardiomyocytes from neonatal mice (2–3 days) and intervening with Ang II (1 μM) to mimic heart failure. Oxidative stress and mitochondrial membrane potential were determined in the cardiomyocytes of each group by DHE and JC-1 staining, respectively. Myocardial fibrosis was increased significantly and cardiac function was reduced significantly in the heart failure mice. Aerobic exercise and SKQ1 intervention improved cardiac function and reduced myocardial hypertrophy and myocardial fibrosis in the heart failure mice significantly. Meanwhile, aerobic exercise and SKQ1 intervention reduced the number of DHE-positive particles (p < 0.01) and inhibited myocardial oxidative stress in the heart failure mice significantly. Aerobic exercise also reduced DRP1, Parkin, and BNIP3 protein expression (p < 0.05, p < 0.01), and increased OPA1 and PINK1 protein expression (p < 0.05, p < 0.01) significantly. Moreover, aerobic exercise and SKQ1 intervention decreased the number of TUNEL-positive particles and the expression of inflammation- and apoptosis-related proteins NLRP3, TXNIP, Caspase-1, IL-1β, BAX, BAK, and p53 significantly (p < 0.05, p < 0.01). In addition, the AMPK agonist AICAR and the mitochondria-targeted ROS scavenger (SKQ1) ameliorated AngII-induced mitochondrial fragmentation and decreased mitochondrial membrane potential in cardiomyocytes significantly. It was shown that inhibition of mitochondrial ROS by aerobic exercise, which in turn inhibits mitochondrial damage, improves mitochondrial quality control, and reduces myocardial inflammatory and apoptosis, may be an important molecular mechanism by which aerobic exercise exerts endogenous antioxidant protective effects to improve cardiac function. Full article

Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system (CNS) linked to many neurological disabilities. The visual system is frequently impaired in MS. In previous studies, we observed early malfunctions of rod photoreceptor ribbon synapses in the EAE mouse model of MS that included alterations in synaptic vesicle cycling and disturbances of presynaptic Ca²⁺ homeostasis. Since these presynaptic events are highly energy-demanding, we analyzed whether synaptic mitochondria, which play a major role in synaptic energy metabolism, might be involved at that early stage. Rod photoreceptor presynaptic terminals contain a single large mitochondrion next to the synaptic ribbon. In the present study, we analyzed the expression of functionally relevant mitochondrial proteins (MIC60, ATP5B, COX1, PINK1, DRP1) by high-resolution qualitative and quantitative immunofluorescence microscopy, immunogold electron microscopy and quantitative Western blot experiments. We observed a decreased expression of many functionally relevant proteins in the synaptic mitochondria of EAE photoreceptors at an early stage, suggesting that early mitochondrial dysfunctions play an important role in the early synapse pathology. Interestingly, mitochondria in presynaptic photoreceptor terminals were strongly compromised in early EAE, whereas extra-synaptic mitochondria in photoreceptor inner segments remained unchanged, demonstrating a functional heterogeneity of photoreceptor mitochondria. Full article

Structural variants (SVs) are one of the main sources of genetic variants and have a significant impact on phenotype evolution, disease susceptibility, and environmental adaptations. We used 73 whole genome sequencing (12x) to apply a mapping approach to identify SVs in five turkey populations. A notable degree of genetic isolation was observed between the Basilicata and Apulian populations, as indicated by principal component analysis and admixture results. A total of 11,733 SVs were detected, including 6712 deletions, 2671 duplications, 1430 inversions, and 920 translocations. The Variant Effect Predictor (VEP) analysis predicted various consequences of filtered SVs as follows: intron variants (35.8%), intergenic variants (9.6%), coding sequence variants (8.3%), downstream gene variants (7.5%), and transcript ablations (7.3%). Our functional annotation of genes overlapping with SVs was mainly enriched in recognized pathways governing positive regulation of nucleoplasm, protein binding, mitochondrion, negative regulation of cell population proliferation, identical protein binding, and calcium signaling. We produced a comprehensive SV catalog utilizing unique whole-genome turkey data. This SV catalog not only increases our understanding of genetic diversity in turkeys but also enhances our knowledge of the role of SVs in their phenotypic traits. Full article

Dominant optic atrophy (DOA) is the most commonly inherited optic neuropathy. The majority of DOA is caused by mutations in the OPA1 gene, which encodes a dynamin-related GTPase located to the mitochondrion. OPA1 has been shown to regulate mitochondrial dynamics and promote fusion. Within the mitochondrion, proteolytically processed OPA1 proteins form complexes to maintain membrane integrity and the respiratory chain complexity. Although OPA1 is broadly expressed, human OPA1 mutations predominantly affect retinal ganglion cells (RGCs) that are responsible for transmitting visual information from the retina to the brain. Due to the scarcity of human RGCs, DOA has not been studied in depth using the disease affected neurons. To enable studies of DOA using stem-cell-derived human RGCs, we performed CRISPR-Cas9 gene editing to generate OPA1 mutant pluripotent stem cell (PSC) lines with corresponding isogenic controls. CRISPR-Cas9 gene editing yielded both OPA1 homozygous and heterozygous mutant ESC lines from a parental control ESC line. In addition, CRISPR-mediated homology-directed repair (HDR) successfully corrected the OPA1 mutation in a DOA patient’s iPSCs. In comparison to the isogenic controls, the heterozygous mutant PSCs expressed the same OPA1 protein isoforms but at reduced levels; whereas the homozygous mutant PSCs showed a loss of OPA1 protein and altered mitochondrial morphology. Furthermore, OPA1 mutant PSCs exhibited reduced rates of oxygen consumption and ATP production associated with mitochondria. These isogenic PSC lines will be valuable tools for establishing OPA1-DOA disease models in vitro and developing treatments for mitochondrial deficiency associated neurodegeneration. Full article

Arthrogryposis, which represents a group of congenital disorders, includes various forms. One such form is amyoplasia, which most commonly presents in a sporadic form in addition to distal forms, among which hereditary cases may occur. This condition is characterized by limited joint mobility and muscle weakness, leading to limb deformities and various clinical manifestations. At present, the pathogenesis of this disease is not clearly understood, and its diagnosis is often complicated due to significant phenotypic diversity, which can result in delayed detection and, consequently, limited options for symptomatic treatment. In this study, a transcriptomic analysis of the affected muscles from patients diagnosed with amyoplasia was performed, and more than 2000 differentially expressed genes (DEGs) were identified. A functional analysis revealed disrupted biological processes, such as vacuole organization, cellular and aerobic respiration, regulation of mitochondrion organization, cellular adhesion, ATP synthesis, and others. The search for key nodes (hubs) in protein–protein interaction networks allowed for the identification of genes involved in mitochondrial processes. Full article