Coenzyme Q10 therapy before cardiac surgery improves mitochondrial function and in vitro contractility of myocardial tissue

Abstract Mitochondria play an important role in controlling oocyte developmental competence. Our previous studies showed that glycine can regulate mitochondrial function and improve oocyte maturation in vitro. However, the mechanisms by which glycine affects mitochondrial function during oocyte maturation in vitro have not been fully investigated. In this study, we induced a mitochondrial damage model in oocytes with the Bcl-2-specific antagonist ABT-199. We investigated whether glycine could reverse the mitochondrial dysfunction induced by ABT-199 exposure and whether it is related to calcium regulation. Our results showed that ABT-199 inhibited cumulus expansion, decreased the oocyte maturation rate and the intracellular glutathione (GSH) level, caused mitochondrial dysfunction, induced oxidative stress, which was confirmed by decreased mitochondrial membrane potential (Δ⍦m) and the expression of mitochondrial function-related genes (PGC-1α), and increased reactive oxygen species (ROS) levels and the expression of apoptosis-associated genes (Bax, caspase-3, CytC). More importantly, ABT-199-treated oocytes showed an increase in the intracellular free calcium concentration ([Ca 2+]i) and had impaired cortical type 1 inositol 1,4,5-trisphosphate receptors (IP3R1) distribution. Nevertheless, treatment with glycine significantly ameliorated mitochondrial dysfunction, oxidative stress and apoptosis, glycine also regulated [Ca 2+]i levels and IP3R1 cellular distribution, which further protects oocyte maturation in ABT-199-induced porcine oocytes. Taken together, our results indicate that glycine has a protective action against ABT-199-induced mitochondrial dysfunction in porcine oocytes.

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Aetiology-dependent impairment of mitochondrial function in the failing human heart

European Heart Journal ◽

10.1093/ehjci/ehaa946.3606 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

J Borger ◽

D Scheiber ◽

P Horn ◽

D Pesta ◽

U Boeken ◽

...

Keyword(s):

Heart Failure ◽

Mitochondrial Function ◽

Human Study ◽

Left Ventricular ◽

Myocardial Tissue ◽

Funding Source ◽

Ros Production ◽

German Research Foundation ◽

Long Term Outcome ◽

Tissue Specimens

Abstract Background Alterations of mitochondrial function have been identified to play a role in Heart Failure (HF) pathophysiology. Oxidative phosphorylation (OXPHOS) capacity of the myocardium was shown to be reduced in the failing heart. Ineffective mitochondrial function promotes formation of reactive oxygen species (ROS) that may affect remodelling in ischemia. Thus far, human mitochondrial function comparing dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) resembling the main aetiologies of heart failure with reduced ejection fraction (HFrEF) has not been investigated. Purpose We hypothesised that 1. ROS production is elevated in left ventricular myocardial tissue specimens of ICM patients compared to DCM. 2. Mitochondrial OXPHOS capacity is higher in left ventricular myocardial tissue specimens of DCM compared to ICM patients. Methods Myocardial tissue was obtained from the left ventricular apex from 63 patients (38 ICM, 25 DCM) with advanced HFrEF requiring implantation of a Left Ventricular Assist Device (LVAD). We performed high-resolution respirometry (HRR, OROBOROS Oxygraph-2k) in saponine-permeabilised myocardial fibres and measured ROS production fluoroscopically via the Amplex Red method. Statistical analysis was conducted using GraphPad Prism 7 and IBM SPSS v26.0. Results Groups were of comparable age (61.5±1.2 vs. 59.3±2.4 years, p=n.s.), sex (87% vs 85% male, p=n.s.), diabetic status (32% vs 38.4% type 2 diabetes mellitus, p=n.s.), and body mass index (28.1±0.8 vs. 26.3±1.1 kg/m2, p=n.s.). We detected reduced myocardial mitochondrial OXPHOS capacity in ICM under state 3 conditions by about 15% (68.7±34.0 vs. 80.9±30.5 pmol/(s*mg), p<0.05), after addition of Glutamate by 25% (78.9±38.7 vs. 104.8±41.2 pmol/(s*mg), p<0.01) as well as after Succinate (115.5±65.5 vs. 155±62.0 pmol/(s*mg), p<0.01), uncoupling agent FCCP (114.1±56.8 vs. 150.5±47.3 pmol/(s*mg), p<0.01), and by about 40% after addition of Complex I inhibitor Rotenone (55.5±25.9 vs. 96.9±28.0 pmol/(s*mg), p<0.001). We detected no difference in ROS production between ICM and DCM (0.6±0.05 vs. 0.76±0.08 pmol/(s*ml), p=n.s.). Conclusion This is the first human study deciphering distinct alterations in mitochondrial function (OXPHOS capacity) in ventricular myocardium of HFrEF patients. Future studies may address how distinct metabolic patterns at the time of implantation may relate to long-term outcome of HFrEF in terms of remodelling and recovery. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): DFG (German Research Foundation)

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158 Inhibition of PI3Kδ improves tumor specific T cell immunity and metabolic fitness

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0158 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A172-A172

Author(s):

Guillermo Rangel Rivera ◽

Guillermo Rangel RIvera ◽

Connor Dwyer ◽

Dimitrios Arhontoulis ◽

Hannah Knochelmann ◽

...

Keyword(s):

T Cells ◽

Cell Differentiation ◽

T Cell ◽

Cell Therapy ◽

Tumor Immunity ◽

Mitochondrial Function ◽

T Cell Differentiation ◽

Tumor Control ◽

T Cell Therapy

BackgroundDurable responses have been observed with adoptive T cell therapy (ACT) in some patients. However, current protocols used to expand T cells often exhibit suboptimal tumor control. Failure in these therapies has been attributed to premature differentiation and impaired metabolism of the infused T cells. Previous work done in our lab showed that reduced PI3Kδ signaling improved ACT. Because PI3Kγ and PI3Kδ have critical regulatory roles in T cell differentiation and function, we tested whether inhibiting PI3Kγ could recapitulate or synergize PI3Kδ blockade.MethodsTo test this, we primed melanoma specific CD8+ pmel-1 T cells, which are specific to the glycoprotein 100 epitope, in the presence of PI3Kγ (IPI-459), PI3Kδ (CAL101 or TGR-1202) or PI3Kγ/δ (IPI-145) inhibitors following antigen stimulation with hgp100, and then infused them into 5Gy total body irradiated B16F10 tumor bearing mice. We characterized the phenotype of the transferred product by flow cytometry and then assessed their tumor control by measuring the tumor area every other day with clippers. For metabolic assays we utilized the 2-NBDG glucose uptake dye and the real time energy flux analysis by seahorse.ResultsSole inhibition of PI3Kδ or PI3Kγ in vitro promoted greater tumor immunity and survival compared to dual inhibition. To understand how PI3Kδ or PI3Kγ blockade improved T cell therapy, we assessed their phenotype. CAL101 treatment produced more CD62LhiCD44lo T cells compared to IPI-459, while TGR-1202 enriched mostly CD62LhiCD44hi T cells. Because decreased T cell differentiation is associated with mitochondrial metabolism, we focused on CAL101 treated T cells to study their metabolism. We found that CAL101 decreased glucose uptake and increased mitochondrial respiration in vitro, indicating augmented mitochondrial function.ConclusionsThese findings indicate that blocking PI3Kδ is sufficient to mediate lasting tumor immunity of adoptively transferred T cells by preventing premature differentiation and improving mitochondrial fitness. Our data suggest that addition of CAL101 to ACT expansion protocols could greatly improve T cell therapies for solid tumors by preventing T cell differentiation and improving mitochondrial function.

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ApoE4 (Δ272–299) induces mitochondrial‐associated membrane formation and mitochondrial impairment by enhancing GRP75-modulated mitochondrial calcium overload in neuron

Cell & Bioscience ◽

10.1186/s13578-021-00563-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tao Liang ◽

Weijian Hang ◽

Jiehui Chen ◽

Yue Wu ◽

Bin Wen ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Er Stress ◽

Mitochondrial Dysfunction ◽

Mitochondrial Function ◽

Calcium Transport ◽

Calcium Overload ◽

Mitochondrial Calcium ◽

Mitochondrial Impairment

Abstract Background Apolipoprotein E4 (apoE4) is a major genetic risk factor of Alzheimer’s disease. Its C-terminal-truncated apoE4 (Δ272–299) has neurotoxicity by affecting mitochondrial respiratory function. However, the molecular mechanism(s) underlying the action of apoE4 (Δ272–299) in mitochondrial function remain poorly understood. Methods The impact of neuronal apoE4 (Δ272–299) expression on ER stress, mitochondrial-associated membrane (MAM) formation, GRP75, calcium transport and mitochondrial impairment was determined in vivo and in vitro. Furthermore, the importance of ER stress or GRP75 activity in the apoE4 (Δ272–299)-promoted mitochondrial dysfunction in neuron was investigated. Results Neuronal apoE4 (Δ272–299) expression induced mitochondrial impairment by inducing ER stress and mitochondrial-associated membrane (MAM) formation in vivo and in vitro. Furthermore, apoE4 (Δ272–299) expression promoted GRP75 expression, mitochondrial dysfunction and calcium transport into the mitochondria in neuron, which were significantly mitigated by treatment with PBA (an inhibitor of ER stress), MKT077 (a specific GRP75 inhibitor) or GRP75 silencing. Conclusions ApoE4 (Δ272–299) significantly impaired neuron mitochondrial function by triggering ER stress, up-regulating GRP75 expression to increase MAM formation, and mitochondrial calcium overload. Our findings may provide new insights into the neurotoxicity of apoE4 (Δ272–299) against mitochondrial function and uncover new therapeutic targets for the intervention of Alzheimer’s disease.

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Effect of cannulation site on emboli travel during cardiac surgery

Journal of Cardiothoracic Surgery ◽

10.1186/s13019-021-01564-1 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Mira Puthettu ◽

Stijn Vandenberghe ◽

Stefanos Demertzis

Keyword(s):

Cardiac Surgery ◽

In Vitro Study ◽

Blood Stream ◽

Air Bubbles ◽

Arterial Tree ◽

Air Bubble ◽

Cannulation Site ◽

The Brain

Abstract Background During cardiac surgery, micro-air emboli regularly enter the blood stream and can cause cognitive impairment or stroke. It is not clearly understood whether the most threatening air emboli are generated by the heart-lung machine (HLM) or by the blood-air contact when opening the heart. We performed an in vitro study to assess, for the two sources, air emboli distribution in the arterial tree, especially in the brain region, during cardiac surgery with different cannulation sites. Methods A model of the arterial tree was 3D printed and included in a hydraulic circuit, divided such that flow going to the brain was separated from the rest of the circuit. Air micro-emboli were injected either in the HLM (“ECC Bubbles”) or in the mock left ventricle (“Heart Bubbles”) to simulate the two sources. Emboli distribution was measured with an ultrasonic bubble counter. Five repetitions were performed for each combination of injection site and cannulation site, where air bubble counts and volumes were recorded. Air bubbles were separated in three categories based on size. Results For both injection sites, it was possible to identify statistically significant differences between cannulation sites. For ECC Bubbles, axillary cannulation led to a higher amount of air bubbles in the brain with medium-sized bubbles. For Heart Bubbles, aortic cannulation showed a significantly bigger embolic load in the brain with large bubbles. Conclusions These preliminary in vitro findings showed that air embolic load in the brain may be dependent on the cannulation site, which deserves further in vivo exploration.

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