Mitochondrial Density Research Articles

Abstract 15199: Pyridoxamine Limits Mitochondria-Dependent Ferroptosis in a Rat Model of Doxorubicin-Induced Cardiotoxicity

Background: The use of doxorubicin (DOX) chemotherapy is limited by cardiotoxicity characterized by mitochondrial iron accumulation and ferroptosis, both interesting targets for cardioprotection. We found that pyridoxamine (PM) protects against DOX cardiotoxicity in rats. In this study, we hypothesized that PM is cardioprotective by restoring iron regulation and limiting mitochondria-dependent ferroptosis. Methods: Female Sprague Dawley rats of six weeks old were divided into a DOX group (2 mg/kg/week, 8 weeks, IV, N=7) or control group (CTRL, saline, N=7). Others were treated with PM via drinking water (1 g/L) while receiving DOX or saline (DOX+PM, N=9 and CTRL+PM, N=8). Iron regulation, lipid peroxidation and mitochondrial damage in cardiac tissue were evaluated by qPCR, 4-hydroxynonenal (4-HNE) staining and transmission electron microscopy. Data were compared by 1-way ANOVA or Kruskal-Wallis test with posthoc tests. P values are presented with a mean difference (MD) and [95% CI] or mean rank difference (MRD). Results: DOX significantly increased ZIP14 (P=0.049 vs CTRL, 11.20 MRD) and mitoferrin-1 expression (P=0.0002 vs CTRL, 1.49 MD [0.71, 2.28]), indicating increased cytosolic and mitochondrial iron import. The DOX group showed features of ferroptosis including swollen mitochondria with disrupted cristae (Fig. 1), decreased mitochondrial density (P=0.085 vs CTRL, –0.12 MD [–0.24, 0.01]) and increased 4-HNE levels (P=0.029 vs CTRL, 6.90 MD [0.56, 13.24]). PM treatment significantly decreased ZIP14 (P=0.0055 vs DOX, –12.90 MRD) and mitoferrin-1 expression (P=0.0008 vs DOX, –1.17 MD, [–1.88, –0.46]), indicating restored iron regulation. PM also significantly increased mitochondrial density (P=0.0028 vs DOX, 0.22 MD [0.06, 0.37]) and limited mitochondrial damage (Fig. 1). Conclusion: In conclusion, we show that PM limits DOX-induced mitochondria-dependent ferroptosis, and could be a promising cardioprotective strategy for cancer patients.

Abstract 213: High-Throughput Analysis of Mitochondrial Morphology in Neurons Post-Mitochondrial Transplantation

Background: Mitochondrial transplantation (MTx) improves neurological and survival outcomes in rats after cardiac arrest. However, the impact of transferred mitochondria on native mitochondrial features in neurons remains poorly assessed. Evaluating mitochondrial morphology provides insights into post-MTx mitochondrial dynamics in recipient neurons, aiding the understanding of cellular processes and targeted therapy development. Aim: To investigate whether increased uptake of donor mitochondria influences the morphology of native mitochondrial networks in neurons. Methods: We conducted in vitro MTx using the HT-22 neuron cell line. Native mitochondria in neurons were pre-labeled with MitoTracker Green. Extracellular mitochondria were isolated from healthy adult rat muscle tissue, labeled with MitoTracker Deep Red, and co-cultured with neurons. Confocal microscopy captured 2D fluorescence images. MitoHacker, a computational program, facilitated high-throughput analysis of 27 mitochondrial morphometric markers. Results: We analyzed 62 images of cells ( Figure ). MitoHacker successfully identified features of native and transferred donor mitochondria. Linear regression analysis revealed that total donor mitochondrial area had positive correlations with native mitochondrial counts, total area, minor axis length of mitochondrion, mitochondrial averaged density, and mitochondrial branch length, and a negative correlation with distance between mitochondrial location and nucleus (all P<0.05). These findings suggest that increased amounts of transferred mitochondria can positively influence native mitochondrial biogenesis, proliferation, accumulation, and activated mitochondrial dynamics and networking in recipient neurons. Conclusion: Using the deep learning-based mitochondrial morphology analysis, our study provides evidence that MTx significantly impacts mitochondrial morphology and dynamics in recipient cells.

Breast adipose tissue-derived extracellular vesicles from obese women alter tumor cell metabolism.

Breast adipose tissue is an important contributor to the obesity-breast cancer link. Extracellular vesicles (EVs) are nanosized particles containing selective cargo, such as miRNAs, that act locally or circulate to distant sites to modulate target cell functions. Here, we find that long-term education of breast cancer cells with EVs obtained from breast adipose tissue of women who are overweight or obese (O-EVs) results in increased proliferation. RNA-seq analysis of O-EV-educated cells demonstrates increased expression of genes involved in oxidative phosphorylation, such as ATP synthase and NADH: ubiquinone oxidoreductase. O-EVs increase respiratory complex protein expression, mitochondrial density, and mitochondrial respiration in tumor cells. The mitochondrial complex I inhibitor metformin reverses O-EV-induced cell proliferation. Several miRNAs-miR-155-5p, miR-10a-3p, and miR-30a-3p-which promote mitochondrial respiration and proliferation, are enriched in O-EVs relative to EVs from lean women. O-EV-induced proliferation and mitochondrial activity are associated with stimulation of the Akt/mTOR/P70S6K pathway, and are reversed upon silencing of P70S6K. This study reveals a new facet of the obesity-breast cancer link with human breast adipose tissue-derived EVs causing metabolic reprogramming of breast cancer cells.

PSXIV-26 Live Animal Longissimus Thoracis Mitochondrial Capacities at 10, 13, and 18 Months of Age Are Related to Meat Quality in Angus and Brahman Steers

Abstract Mitochondrial abundance and efficiency correlate with meat color, but relationships between live animal mitochondria and other markers of beef quality remain largely unknown. To test the hypothesis that live animal skeletal muscle mitochondrial markers would be correlated with post-harvest hot carcass weight, ribeye area, calculated yield grade, backfat thickness, and marbling, samples were collected from the longissimus thoracis of Brahman and Angus steers at 10 mo (25 Angus, 23 Brahman), 13 mo (35 Angus, 33 Brahman), and 18 mo (35 Angus, 33 Brahman) of age. Mitochondrial volume density and function were quantified by citrate synthase (CS) and cytochrome c oxidase activities, respectively. Mitochondrial oxidative phosphorylation (OxP) and electron transfer (E) capacities were determined via high-resolution respirometry. Relationships between mitochondrial variables and carcass quality were determined using PROC CORR in SAS (v9.4). Within Angus at 10 mo, integrative (per mg tissue) complex I-supported OxP (PCI), maximal OxP (PCI+II), maximal E (ECI+II), and E supported by complex II (ECII) were positively correlated with hot carcass weight (P ≤ 0.05). Also, within 10 mo Angus, integrative OxPCI and flux control ratio (FCR) for OxPCI were positively correlated with backfat thickness (P ≤ 0.03). Within 10 mo Brahman, integrative PCI was positively correlated with ribeye area (P = 0.04). Within 13 mo Brahman, integrative mitochondrial proton LEAK was positively correlated with hot carcass weight (P = 0.02) and intrinsic (relative to CS activity) LEAK, PCI, and ECI+II were positively correlated with marbling (P ≤ 0.05). Conversely, CS activity was negatively correlated with marbling in 13 mo Brahman (P = 0.05). Integrative, FCR, and intrinsic LEAK were negatively correlated with ribeye area (P ≤ 0.05) but positively correlated with calculated yield grade in 13 mo Angus (P ≤ 0.03). However, at 18 mo, integrative, FCR, and intrinsic LEAK were positively correlated with ribeye area (P ≤ 0.008) but negatively correlated with calculated yield grade (P ≤ 0.01) in Angus steers. Furthermore, integrative and intrinsic OxPCI+II, ECI+II, and ECII were positively correlated with marbling in 18 mo Angus (P ≤ 0.04). Within 18 mo Brahman, CS activity was positively correlated with ribeye area (P = 0.006). Cytochrome c oxidase activity was not correlated with any markers of meat quality. These results suggest that mitochondrial capacity for energy production in Angus and Brahman steers at different life and production stages may dictate potential for skeletal muscle growth and lipid metabolism leading to differences in beef quality at slaughter. This project was supported by USDA NIFA Award #2021-67015-33392.

A human mitofusin 2 mutation can cause mitophagic cardiomyopathy.

Cardiac muscle has the highest mitochondrial density of any human tissue, but mitochondrial dysfunction is not a recognized cause of isolated cardiomyopathy. Here, we determined that the rare mitofusin (MFN) 2 R400Q mutation is 15-20× over-represented in clinical cardiomyopathy, whereas this specific mutation is not reported as a cause of MFN2 mutant-induced peripheral neuropathy, Charcot-Marie-Tooth disease type 2A (CMT2A). Accordingly, we interrogated the enzymatic, biophysical, and functional characteristics of MFN2 Q400 versus wild-type and CMT2A-causing MFN2 mutants. All MFN2 mutants had impaired mitochondrial fusion, the canonical MFN2 function. Compared to MFN2 T105M that lacked catalytic GTPase activity and exhibited normal activation-induced changes in conformation, MFN2 R400Q and M376A had normal GTPase activity with impaired conformational shifting. MFN2 R400Q did not suppress mitochondrial motility, provoke mitochondrial depolarization, or dominantly suppress mitochondrial respiration like MFN2 T105M. By contrast to MFN2 T105M and M376A, MFN2 R400Q was uniquely defective in recruiting Parkin to mitochondria. CRISPR editing of the R400Q mutation into the mouse Mfn2 gene induced perinatal cardiomyopathy with no other organ involvement; knock-in of Mfn2 T105M or M376V did not affect the heart. RNA sequencing and metabolomics of cardiomyopathic Mfn2 Q/Q400 hearts revealed signature abnormalities recapitulating experimental mitophagic cardiomyopathy. Indeed, cultured cardiomyoblasts and in vivo cardiomyocytes expressing MFN2 Q400 had mitophagy defects with increased sensitivity to doxorubicin. MFN2 R400Q is the first known natural mitophagy-defective MFN2 mutant. Its unique profile of dysfunction evokes mitophagic cardiomyopathy, suggesting a mechanism for enrichment in clinical cardiomyopathy.

Chronic Intermittent Hypoxia-Induced Dysmetabolism Is Associated with Hepatic Oxidative Stress, Mitochondrial Dysfunction and Inflammation.

The association between obstructive sleep apnea (OSA) and metabolic disorders is well-established; however, the underlying mechanisms that elucidate this relationship remain incompletely understood. Since the liver is a major organ in the maintenance of metabolic homeostasis, we hypothesize that liver dysfunction plays a crucial role in the pathogenesis of metabolic dysfunction associated with obstructive sleep apnea (OSA). Herein, we explored the underlying mechanisms of this association within the liver. Experiments were performed in male Wistar rats fed with a control or high fat (HF) diet (60% lipid-rich) for 12 weeks. Half of the groups were exposed to chronic intermittent hypoxia (CIH) (30 hypoxic (5% O2) cycles, 8 h/day) that mimics OSA, in the last 15 days. Insulin sensitivity and glucose tolerance were assessed. Liver samples were collected for evaluation of lipid deposition, insulin signaling, glucose homeostasis, hypoxia, oxidative stress, antioxidant defenses, mitochondrial biogenesis and inflammation. Both the CIH and HF diet induced dysmetabolism, a state not aggravated in animals submitted to HF plus CIH. CIH aggravates hepatic lipid deposition in obese animals. Hypoxia-inducible factors levels were altered by these stimuli. CIH decreased the levels of oxidative phosphorylation complexes in both groups and the levels of SOD-1. The HF diet reduced mitochondrial density and hepatic antioxidant capacity. The CIH and HF diet produced alterations in cysteine-related thiols and pro-inflammatory markers. The results obtained suggest that hepatic mitochondrial dysfunction and oxidative stress, leading to inflammation, may be significant factors contributing to the development of dysmetabolism associated with OSA.

Mitochondrial Function in Healthy Human White Adipose Tissue: A Narrative Review.

As ¾ of the global population either have excess or insufficient fat, it has become increasingly critical to understand the functions and dysfunctions of adipose tissue (AT). AT serves as a key organ in energy metabolism, and recently, attention has been focused on white AT, particularly its mitochondria, as the literature evidence links their functions to adiposity. This narrative review provides an overview of mitochondrial functionality in human white AT. Firstly, it is noteworthy that the two primary AT depots, subcutaneous AT (scAT) and visceral AT (vAT), exhibit differences in mitochondrial density and activity. Notably, vAT tends to have a higher mitochondrial activity compared to scAT. Subsequently, studies have unveiled a negative correlation between mitochondrial activity and body mass index (BMI), indicating that obesity is associated with a lower mitochondrial function. While the impact of exercise on AT mitochondria remains uncertain, dietary interventions have demonstrated varying effects on AT mitochondria. This variability holds promise for the modulation of AT mitochondrial activity. In summary, AT mitochondria exert a significant influence on health outcomes and can be influenced by factors such as obesity and dietary interventions. Understanding the mechanisms underlying these responses can offer potential insights into managing conditions related to AT and overall health.

Identification of Ferroptosis-related potential biomarkers and immunocyte characteristics in Chronic Thromboembolic Pulmonary Hypertension via bioinformatics analysis

BackgroundChronic Thromboembolic Pulmonary Hypertension (CTEPH) is a form of pulmonary hypertension with a high mortality rate. A new type of iron-mediated cell death is Ferroptosis, which is characterized by the accumulation of lethal iron ions and lipid peroxidation leading to mitochondrial atrophy and increased mitochondrial membrane density. Now, there is a lack of Ferroptosis-related biomarkers (FRBs) associated with pathogenic process of CTEPH.MethodsThe differentially expressed genes (DEGs) of CTEPH were obtained by GEO2R. Genes related to Ferroptosis were obtained from FerrDb database. The intersection of Ferroptosis and DEGs results in FRBs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed in Database for Annotation, Visualization and Integrated Discovery (DAVID) database. The optimal potential biomarkers for CTEPH were analyzed by least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE) machine learning. The four hub genes were verified from the Gene Expression Omnibus (GEO) dataset GSE188938. Immune infiltration was analyzed by CIBERSORT. SPSS software was used to analyze the Spearman rank correlation between FRBs identified and infiltration-related immune cells, and p < 0.05 was considered as statistically significant.ResultsIn this study, potential genetic biomarkers associated with Ferroptosis in CTEPH were investigated and explored their role in immune infiltration. In total, we identified 17 differentially expressed Ferroptosis-associated genes by GEOquery package. The key FRBs including ARRDC3, HMOX1, BRD4, and YWHAE were screened using Lasso and SVM-RFE machine learning methods.Through gene set GSE188938 verification, only upregulation of gene ARRDC3 showed statistical difference. In addition, immune infiltration analysis using the CIBERSORT algorithm revealed the infiltration of Eosinophils and Neutrophils in CTEPH samples was less than that in the control group. And correlation analysis revealed that ARRDC3 was positively correlated with T cells follicular helper (r = 0.554, p = 0.017) and negatively correlated with Neutrophils (r = -0.47, p = 0.049).ConclusionsIn conclusion, ARRDC3 upregulation with different immune cell infiltration were involved in the development of CTEPH. ARRDC3 might a potential Ferroptosis-related biomarker for CTEPH treatment. This study provided a new insight into pathogenesis CTEPH.

FAM210A is essential for cold-induced mitochondrial remodeling in brown adipocytes

Cold stimulation dynamically remodels mitochondria in brown adipose tissue (BAT) to facilitate non-shivering thermogenesis in mammals, but what regulates mitochondrial plasticity is poorly understood. Comparing mitochondrial proteomes in response to cold revealed FAM210A as a cold-inducible mitochondrial inner membrane protein. An adipocyte-specific constitutive knockout of Fam210a (Fam210aAKO) disrupts mitochondrial cristae structure and diminishes the thermogenic activity of BAT, rendering the Fam210aAKO mice vulnerable to lethal hypothermia under acute cold exposure. Induced knockout of Fam210a in adult adipocytes (Fam210aiAKO) does not affect steady-state mitochondrial structure under thermoneutrality, but impairs cold-induced mitochondrial remodeling, leading to progressive loss of cristae and reduction of mitochondrial density. Proteomics reveals an association between FAM210A and OPA1, whose cleavage governs cristae dynamics and mitochondrial remodeling. Mechanistically, FAM210A interacts with mitochondrial protease YME1L and modulates its activity toward OMA1 and OPA1 cleavage. These data establish FAM210A as a key regulator of mitochondrial cristae remodeling in BAT and shed light on the mechanism underlying mitochondrial plasticity in response to cold.

ATP synthase-associated coiled-coil-helix-coiled-coil-helix (CHCH) domain-containing proteins are critical for mitochondrial function in Toxoplasma gondii.

Members of the coiled-coil-helix-coiled-coil-helix (CHCH) domain protein family are transported into the mitochondrial intermembrane space, where they play important roles in the biogenesis and function of the organelle. Unexpectedly, the ATP synthase of the apicomplexan Toxoplasma gondii harbors CHCH domain-containing subunits of unknown function. As no other ATP synthase studied to date contains this class of proteins, characterizing their function will be of broad interest to the fields of molecular parasitology and mitochondrial evolution. Here, we demonstrate that that two T. gondii ATP synthase subunits containing CHCH domains are required for parasite survival and for stability and function of the ATP synthase. We also show that knockdown disrupts multiple aspects of the mitochondrial morphology of T. gondii and that mutation of key residues in the CHCH domains caused mis-localization of the proteins. This work provides insight into the unique features of the apicomplexan ATP synthase, which could help to develop therapeutic interventions against this parasite and other apicomplexans, such as the malaria-causing parasite Plasmodium falciparum.

Shikonin Causes Non-apoptotic Cell Death in B16F10 Melanoma.

Melanoma treatment is highly resistant to current chemotherapeutic agents. Due to its resistance towards apoptotic cell death, non-apoptotic cell death pathways are sought after. We investigated a Chinese herbal medicine, shikonin, and its effect on B16F10 melanoma cells in vitro. Cell growth of B16F10 melanoma cells treated with shikonin was analyzed using an MTT assay. Shikonin was combined with necrostatin, an inhibitor of necroptosis; caspase inhibitor; 3-methyladenine, an inhibitor of autophagy; or N-acetyl cysteine, an inhibitor of reactive oxygen species. Flow cytometry was used to assess types of cell death resulting from treatment with shikonin. Cell proliferation was also analyzed utilizing a BrdU labeling assay. Monodansylcadaverine staining was performed on live cells to gauge levels of autophagy. Western blot analysis was conducted to identify specific protein markers of necroptosis including CHOP, RIP1, and pRIP1. MitoTracker staining was utilized to identify differences in mitochondrial density in cells treated with shikonin. Analysis of MTT assays revealed a large decrease in cellular growth with increasing shikonin concentrations. The MTT assays with necrostatin, 3-methyladenine, and N-acetyl cysteine involvement, suggested that necroptosis, autophagy, and reactive oxygen species are a part of shikonin's mechanism of action. Cellular proliferation with shikonin treatment was also decreased. Western blotting confirmed that shikonin-treated melanoma cells increase levels of stress-related proteins, e.g., CHOP, RIP, pRIP. Our findings suggest that mainly necroptosis is induced by the shikonin treatment of B16F10 melanoma cells. Induction of ROS production and autophagy are also involved.

Effects of Mifepristone Solid Lipid Nanoparticles on Cardiac Structure and Function in Rats Undergoing Induction of Labor at Full Term

This research was aimed to analyze the biological characteristics of mifepristone solid lipid nanoparticles (MFP/SLNs) and their effects on the cardiac function of rats undergoing induction of labor at full term (FTIL). MFP was loaded into SLNs to prepare MFP/SLNs. The morphology and particle size (PS) of MFP/SLNs were observed by transmission electron microscopy (TEM), and the PS distribution (PSD) and potential distribution of MFP/SLNs were analyzed by Zeta analyzer. The drug loading (DL) and encapsulation efficiency (EE) of MFP/SLNs were calculated, and the crystal form of the drug in the carrier was detected by differential scanning calorimetry (DSC). Fifteen pregnant rats were randomly rolled into a blank (BLK) group, an MFP group, and an MFP/SLNs group, with five rats in each. Those in the MFP/SLNs and the MFP groups were administered MFP/SLNs (10 mg) and MFP by gavage on the 20th day of pregnancy. The changes in myocardial tissue of rats in the MFP/SLNs and MFP groups were observed within 24 hours after delivery and analyzed by a multifunctional true-color pathological image analysis system. The results indicated that MFP/SLNs had a spherical shape and uniform PSD, with an average PS of about 153 nm. The drug EE of MFP/SLNs exceeded 88% when the drug dosage was 50 mg. The MFP group showed obvious cytoplasmic edema in myocardial cells, an increased average mitochondrial volume density (MVD), and glycogen granule deposition. The area of myocardial cells in the MFP group was obviously larger than that in the MFP/SLNs group (P &lt; 0.05), and the nuclear-cytoplasmic ratio (NCR) was much smaller (P &lt; 0.05). These findings suggested that MFP/SLNs were successfully prepared, and MFP can cause changes in the cardiac structure of rats undergoing FTIL, resulting in hypoxic injury. However, MFP/SLNs may protect the cardiac structure and function of rats.

Skeletal muscle adaptations in patients with lung cancer: Longitudinal observations from the whole body to cellular level.

Cancer and its treatment can adversely affect skeletal muscle, impacting physical function, treatment response and survival. No studies, however, have comprehensively characterized these muscle adaptations longitudinally in human patients at the cellular level. We examined skeletal muscle size and function from the whole body to the sub-cellular level in 11 patients with non-small cell lung cancer (NSCLC; 6 male/5 female, mean age 58±3years) studied over a 2-month observation period starting during their first cycle of standard of care cancer treatment and in 11 age- and sex-matched healthy controls (HC) without a current or past history of cancer. Biopsies of the vastus lateralis were performed to assess muscle fibre size, contractility and mitochondrial content, along with assessments of physical function, whole muscle size and function, and circulating cytokines. Body weight, composition and thigh muscle area and density were unaltered over time in patients with NSCLC, while muscle density was lower in patients with NSCLC versus HC (P=0.03). Skeletal muscle fibre size decreased by 18% over time in patients (all P=0.02) and was lower than HC (P=0.02). Mitochondrial fractional area and density did not change over time in patients, but fractional area was lower in patients with NSCLC compared with HC (subsarcolemmal, P=0.04; intermyofibrillar, P=0.03). Patients with NSCLC had higher plasma concentrations of IL-6 (HC 1.40±0.50; NSCLC 4.71±4.22; P<0.01), GDF-15 (HC 569±166; NSCLC 2071±1168; P<0.01) and IL-8/CXCL8 (HC 4.9±1.8; NSCLC 10.1±6.0; P=0.02) compared with HC, but there were no changes in inflammatory markers in patients with NSCLC over time. No changes were observed in markers of satellite cell activation or DNA damage in patients and no group differences were noted with HC. Whole-muscle strength was preserved over time in patients with NSCLC coincident with improved single fibre contractility. This study is the first to comprehensively examine longitudinal alterations in skeletal muscle fibre size and function in patients with NSCLC and suggests that muscle fibre atrophy occurs during cancer treatment despite weight stability and no changes in conventional clinical measurements of whole body or thigh muscle size over this period.

Telomere length links with physiological phenotype and breeding patterns in a long-lived seabird

Abstract Telomere length (TL) is known to covary with a suite of physiological traits involved in energy balances that may influence breeding success. Thus, TL may be an indicator of individual quality, influencing mate choice and breeding strategies. In the Brown Booby (Sula leucogaster), a long-lived seabird, we investigated in a total of 72 pairs whether TL may indicate the individual physiological phenotype by examining how it relates to mitochondrial DNA copy number (mtDNAcn) and corticosterone (CORT) levels. Then, we tested if TL is associated with mating patterns by looking for covariation with skin coloration (a condition-dependent sexual trait), whether there is assortative mating by TL, and if the degree of TL similarity between partners influences an individual’s likelihood of changing mates between reproductive seasons. Because environmental conditions can have important effects on the condition and reproductive strategies of individuals, the study was performed in 2 colonies with contrasting breeding conditions. We found that TL was positively related to mtDNAcn (but not CORT levels), suggesting that individuals with shorter telomeres may have a reduced mitochondrial density. TL was reflected in sexual coloration, but only in the colony with good breeding conditions. There was positive assortative mating by TL; however, the degree of assortative mating was unrelated to the probability of mate change, which greatly varied between the 2 colonies. Our results suggest that TL is associated with the physiological phenotype of individuals and their breeding patterns. Importantly, contrasting environmental conditions influenced the link between TL and sexual coloration and the propensity of individuals to change mate, highlighting the importance of environmental variation on mating patterns.

Changes in physical architecture and lipids compounds in skeletal muscle from Pekin duck and Liancheng white duck

As a complex food, meat displays various biochemical properties that are determined to a great extent by physical architecture and lipid metabolites. Pekin duck and Liancheng white duck are elite breeds with distinct characteristics. Here, we explored the development of the muscle fibers from embryonic stage to 10-wk after birth, and muscle fibers grow slowly after 8-wk. We investigated the meat quality, ultrastructure, lipidomics profiling, and lipids spatial distribution of skeletal muscle at 8 wk. Pekin duck has lower Warner-Bratzler shear force (WBSF) (P < 0.05), high intramuscular fat (IMF) (P < 0.01), longer and wider sarcomere, and higher mitochondrial density (P < 0.001). Liancheng white duck with tighter collagen architecture. A total of 950 lipids from 6 lipid classes identified with lipidomics were analyzed, the levels of GP, GL, and PR were significantly higher in Pekin duck (P < 0.05), SL and ST were significantly higher in Liancheng white duck (P < 0.05). There were 333 significantly different lipids (|log2(Fold Change)| ≥ 1 and FDR < 0.05) screened, most lipids distributed in the muscle tissue were uniform, but some specifically distributed in connective tissue. To some extent, the results demonstrate the high lipid deposition capacity of Pekin duck and the high medicinal function of Liancheng white duck. Our study provides new insights into the relationship between skeletal muscle architecture and meat toughness, which increased the knowledge of lipidomic characteristics and provide a basis for duck meat authentication.

Higher mitochondrial oxidative capacity is the primary molecular differentiator in muscle of rats with high and low intrinsic cardiorespiratory fitness

ObjectiveCardiorespiratory fitness (CRF) is tightly linked with health and longevity and is implicated in metabolic flexibility and substrate metabolism. The high capacity runner (HCR) and low capacity runner (LCR) rat lines are a genetically heterogeneous rat model selected and bred for CRF that reflect CRF in humans by exhibiting differences in nutrient handling. This study aims to differentiate the intrinsic substrate preference of the HCR compared to LCR rats to better understand the intersection of mitochondrial respiration and intrinsic CRF. MethodsWe performed bulk skeletal muscle RNA-Sequencing on male and female HCR and LCR rats and assessed the effect of rat line on mitochondrial gene expression pathways using the MitoCarta3.0 database. In a separate cohort of rats, mitochondria were isolated from skeletal and cardiac muscle and maximal oxidation rates were measured using an Oroboros O2k when provided either pyruvate or fatty acid substrates. ResultsThe expression of mitochondrial genes are significantly upregulated in HCR skeletal muscle in both male and female rats. In respirometry experiments, fatty acid oxidative capacities were greater in HCR compared to LCR, and male compared to female rats, as a function of both mitochondrial quality and mitochondrial density. This effect was greater in the skeletal muscle than in the heart. Pyruvate oxidation did not differ significantly between lines. ConclusionsThe capacity for increased fatty acid oxidation in the HCR rat is a result of selection for running capacity and is likely a key contributor to the healthy metabolic phenotype of individuals with high CRF.

Intertidal limits shape covariation between metabolic plasticity, oxidative stress and telomere dynamics in Pacific oyster (Crassostrea gigas)

In intertidal zones, species such as sessile shellfish exhibit extended phenotypic plasticity to face rapid environmental changes, but whether frequent exposure to intertidal limits of the distribution range impose physiological costs for the animal remains elusive. Here, we explored how phenotypic plasticity varied along foreshore range at multiple organization levels, from molecular to cellular and whole organism acclimatization, in the Pacific oyster (Crassostrea gigas). We exposed 7-month-old individuals for up to 16 months to three foreshore levels covering the vertical range for this species, representing 20, 50 and 80% of the time spent submerged monthly. Individuals at the upper range limit produced energy more efficiently, as seen by steeper metabolic reactive norms and unaltered ATP levels despite reduced mitochondrial density. By spending most of their time emerged, oysters mounted an antioxidant shielding concomitant with lower levels of pro-oxidant proteins and postponed age-related telomere attrition. Instead, individuals exposed at the lower limit range near subtidal conditions showed lower energy efficiencies, greater oxidative stress and shorter telomere length. These results unraveled the extended acclimatization strategies and the physiological costs of living too fast in subtidal conditions for an intertidal species.

Lupenone-Rich Fraction Derived from Cissus quadrangularis L. Suppresses Lipid Accumulation in 3T3-L1 Adipocytes.

Cissus quadrangularis L. (CQ) has potential as a therapeutic for managing obesity and balancing metabolic activity, but the main bioactive compound and regulatory mechanism remain unknown. Herein, the CQ hexane extract was fractionated into 30 fractions (CQ-H) using flash column chromatography and analyzed using thin-layer chromatography. The direct antiadipogenesis effect of CQ-H fractions was tested on 3T3-L1 preadipocytes. Lupenone-rich fractions 2H and 3H were identified as containing potent antiadipogenesis agents that reduced differentiated cell numbers and intracellular lipid droplet size. Although the overall mitochondrial density remained unchanged, differentiated cells exhibited a higher mitochondrial density than that in non-differentiated cells. Additionally, 2H increased mitochondrial activity in both cell types as shown by their differentiation and lipid formation stages. Lupenone was isolated from 2H (Lu-CQ) and shown to dose-dependently inhibit adipogenesis, with 2H being more potent than Lu-CQ. Lu-CQ and 2H downregulated the expression of Pparg2 mRNA and upregulated that of glucose transporter genes, Slc2a1 and Slc2a4. Lu-CQ and 2H induced increased glucose uptake by 3T3-L1 cells. These findings suggest that lupenone-rich fractions in CQ contribute to balancing metabolic activity and reducing adipose tissue formation. Further exploration of CQ and its components may prompt innovative strategies for managing obesity and metabolic disorders.

Prenatal transportation stress does not impact resting skeletal muscle mitochondrial function or antioxidant activity in Brahman calves

In cattle, prenatal transportation stress has been associated with differential methylation of genes related to metabolism, but the effects of prenatal transportation stress on skeletal muscle mitochondria and oxidative stress have not been investigated. We tested the hypothesis that prenatally stressed calves would exhibit increased skeletal muscle mitochondrial function resulting in greater oxidative stress than calves from non-stressed dams. Serum and longissimus thoracis muscle samples were collected from yearling Brahman calves whose mothers were stressed by transportation at five time points during gestation [i.e., prenatally stressed (PNS); eight bulls and six heifers] and control calves (CON; four bulls and six heifers). Serum was evaluated for concentration of the stress hormone, cortisol and for a marker of muscle perturbation, creatine kinase activity. Muscle samples were analyzed for concentration of a by-product of lipid peroxidation, malondialdehyde, and activity of the antioxidants, superoxide dismutase and glutathione peroxidase. Additionally, muscle mitochondrial volume density and function were estimated by citrate synthase and cytochrome c oxidase activities, respectively. Data were analyzed using mixed linear models with sex, treatment, and the sex × treatment interaction as fixed effects. No investigated variable differed between CON and PNS calves (p ≥ 0.3). These data suggest that prenatal transportation stress does not have an impact on skeletal muscle mitochondrial metabolism or markers of stress or muscle damage in Brahman yearling calves at rest. However, previously reported negative impacts of prenatal stress on inflammatory responses suggest that PNS calves may be differentially equipped to handle an acute stressor. Future research should investigate the energetic and inflammatory implications of acute stressors in animals subjected to prenatal stress.

Randomized controlled trial investigating potential effects of relaxation on mitochondrial function in immune cells: A pilot experiment

This study aimed to investigate the effect of a relaxation response induced by hypnosis on the mitochondrial energy production of immune cells compared to an everyday relaxing situation. Chronically stressed individuals (88% women) with at least moderate suggestibility were randomized to a hypnosis (20 min relaxation hypnosis; n = 20) or a control condition (20 min documentary; n = 22). Before and after intervention, peripheral blood was collected. The primary outcomes were mitochondrial respiration and density in immune cells measured by high-resolution respirometry and citrate synthase activity assays. As secondary outcome, perceived stress, anxiety, and depressive mood were assessed. The intervention led to no significant Group × Time effects on mitochondrial bioenergetic parameters but a significant Time effect (ηp2 = .09 –.10). Thus, there were no differences in the experimental conditions concerning the measured parameters of mitochondrial bioenergetics. Exploratory subanalyses indicated that stress, anxiety, and depressive mood were linked to lower mitochondrial respiration. Individuals with higher anxiety had less decrease in routine respiration over time than those with lower anxiety (ηp2 = .09). This study explores the effects of relaxation in the form of hypnosis compared to watching a video on the energy metabolism of immune cells. Relaxation, whether in targeted (hypnosis) or untargeted (documentary) form, affected mitochondrial respiration. Further research should focus on the long-term effects of relaxation on bioenergetics. The trial was retrospectively registered on 07/12/2021, DRKS00027356, https://drks.de/search/de/trial/DRKS00027356