Analysis of Mitochondrial Morphology and Function Under Conditions of Mitofusin 2 Deficiency

2015 ◽  
pp. 307-320 ◽  
Author(s):  
Juan Pablo Muñoz ◽  
Antonio Zorzano
Keyword(s):  
Mitochondrial Morphology ◽  
Mitofusin 2 ◽  
And Function

scholarly journals Cerebrovascular function and mitochondrial bioenergetics after ischemia-reperfusion in male rats

2017 ◽  
Vol 39 (6) ◽  
pp. 1056-1068 ◽  
Author(s):  
Ibolya Rutkai ◽  
Ivan Merdzo ◽  
Sanjay V Wunnava ◽  
Genevieve T Curtin ◽  
Prasad VG Katakam ◽  
...  
Keyword(s):  
Ischemia Reperfusion ◽  
Cerebral Arteries ◽  
Male Rats ◽  
Mitochondrial Morphology ◽  
Sprague Dawley ◽  
Mitofusin 2 ◽  
Cerebrovascular Function ◽  
Sprague Dawley Rats ◽  
Activity Measurements ◽  
And Function

The underlying factors promoting increased mitochondrial proteins, mtDNA, and dilation to mitochondrial-specific agents in male rats following tMCAO are not fully elucidated. Our goal was to determine the morphological and functional effects of ischemia/reperfusion (I/R) on mitochondria using electron microscopy, Western blot, mitochondrial oxygen consumption rate (OCR), and Ca2+ sparks activity measurements in middle cerebral arteries (MCAs) from male Sprague Dawley rats (Naïve, tMCAO, Sham). We found a greatly increased OCR in ipsilateral MCAs (IPSI) compared with contralateral (CONTRA), Sham, and Naïve MCAs. Consistent with our earlier findings, the expression of Mitofusin-2 and OPA-1 was significantly decreased in IPSI arteries compared with Sham and Naïve. Mitochondrial morphology was disrupted in vascular smooth muscle, but morphology with normal and perhaps greater numbers of mitochondria were observed in IPSI compared with CONTRA MCAs. Consistently, there were significantly fewer baseline Ca2+ events in IPSI MCAs compared with CONTRA, Sham, and Naïve. Mitochondrial depolarization significantly increased Ca2+ sparks activity in the IPSI, Sham, Naïve, but not in the CONTRA group. Our data indicate that altered mitochondrial structure and function occur in MCAs exposed to I/R and that these changes impact not only OCR but Ca2+ sparks activity in both IPSI and CONTRA MCAs.

scholarly journals β-Hydroxybutyrate Increases Exercise Capacity Associated with Changes in Mitochondrial Function in Skeletal Muscle

Nutrients ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1930
Author(s):  
Matías Monsalves-Alvarez ◽  
Pablo Esteban Morales ◽  
Mauricio Castro-Sepulveda ◽  
Carlos Sepulveda ◽  
Juan Manuel Rodriguez ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Capacity ◽  
Tibialis Anterior ◽  
Performance Test ◽  
Term Treatment ◽  
Mitochondrial Morphology ◽  
Time To Exhaustion ◽  
Short Term Treatment ◽  
Mitofusin 2 ◽  
And Function

β-hydroxybutyrate is the main ketone body generated by the liver under starvation. Under these conditions, it can sustain ATP levels by its oxidation in mitochondria. As mitochondria can modify its shape and function under different nutritional challenges, we study the chronic effects of β-hydroxybutyrate supplementation on mitochondrial morphology and function, and its relation to exercise capacity. Male C57BL/6 mice were supplemented with β-hydroxybutyrate mineral salt (3.2%) or control (CT, NaCl/KCl) for six weeks and submitted to a weekly exercise performance test. We found an increase in distance, maximal speed, and time to exhaustion at two weeks of supplementation. Fatty acid metabolism and OXPHOS subunit proteins declined at two weeks in soleus but not in tibialis anterior muscles. Oxygen consumption rate on permeabilized fibers indicated a decrease in the presence of pyruvate in the short-term treatment. Both the tibialis anterior and soleus showed decreased levels of Mitofusin 2, while electron microscopy assessment revealed a significant reduction in mitochondrial cristae shape in the tibialis anterior, while a reduction in the mitochondrial number was observed only in soleus. These results suggest that short, but not long-term, β-hydroxybutyrate supplementation increases exercise capacity, associated with modifications in mitochondrial morphology and function in mouse skeletal muscle.

scholarly journals Expression of mitofusin 2 in human sperm and its relationship to sperm motility and cryoprotective potentials

2018 ◽  
Vol 243 (12) ◽  
pp. 963-969 ◽  
Author(s):  
Fang Fang ◽  
Ke Ni ◽  
Jin Shang ◽  
Xiaoke Zhang ◽  
Chengliang Xiong ◽  
...  
Keyword(s):  
Survival Rate ◽  
Membrane Protein ◽  
Sperm Motility ◽  
Human Sperm ◽  
Expression Level ◽  
Mitochondrial Morphology ◽  
Mitofusin 2 ◽  
Exact Function ◽  
Significant Difference ◽  
And Function

Mitofusin 2 is a kind of mitochondria membrane protein that has been implicated in maintenance of mitochondrial morphology and function. However, the expression and function of mitofusin 2 in human sperm are not well described at present. The aim of this study was to explore the location of mitofusin 2 in human sperm and to discover its relationship to human sperm functions like motility and cryoprotective potentials. Our result showed that mitofusin 2 is specifically localized in the 5–7 μm midpiece between the neck and main part of human sperm tail. The expression level of mitofusin 2 in human sperm was significantly different between the normozoospermia and asthenozoospermia groups ( P < 0.05); meanwhile, the sperm of the asthenozoospermia group had a lower mitochondrial membrane potential ( P < 0.05), but the results of TUNEL assay did not show significant difference between the two groups. Furthermore, we found that the expression level of mitofusin 2 in the freeze-resistant group (cryo-survival rate >40%) was significantly higher than that of the freeze-intolerant group (cryo-survival rate ≤40%) ( P < 0.05). These results demonstrate that the expression level of mitofusin 2 is related to motility and cryoprotective potentials of human sperm. Mitofusin 2 may play a crucial role in the function of human sperm, which needs further research to discover the mechanism. Impact statement The exact function of mitochondria in human sperm before and during fertilization process remains controversial. MFN2 is a kind of mitochondria membrane protein and participates in the regulation of mitochondrial morphology and function. In this study, we discover the relationship of MFN2 expression to human sperm motility and cryoprotective potentials. Our results suggest that MFN2 could be a new target for the mechanism research of asthenozoospermia. MFN2 may also serve as a protein marker predicting the ability of human sperm to sustain cryopreservation.

scholarly journals Heterochronic Parabiosis: Old Blood Induces Changes in Mitochondrial Structure and Function of Young Mice

2020 ◽  
Author(s):  
Jenny L Gonzalez-Armenta ◽  
Ning Li ◽  
Rae-Ling Lee ◽  
Baisong Lu ◽  
Anthony J A Molina
Keyword(s):  
Mitochondrial Respiration ◽  
Complex I ◽  
Structure And Function ◽  
Muscle Performance ◽  
Mitochondrial Morphology ◽  
Positive Effects ◽  
Mitochondrial Structure ◽  
And Function ◽  
Old Mice ◽  
Young Mice

Abstract Heterochronic parabiosis models have been utilized to demonstrate the role of blood-borne circulating factors in systemic effects of aging. In previous studies, heterochronic parabiosis has shown positive effects across multiple tissues in old mice. More recently, a study demonstrated old blood had a more profound negative effect on muscle performance and neurogenesis of young mice. In this study, we used heterochronic parabiosis to test the hypothesis that circulating factors mediate mitochondrial bioenergetic decline, a well-established biological hallmark of aging. We examined mitochondrial morphology, expression of mitochondrial complexes, and mitochondrial respiration from skeletal muscle of mice connected as heterochronic pairs, as well as young and old isochronic controls. Our results indicate that young heterochronic mice had significantly lower total mitochondrial content and on average had significantly smaller mitochondria compared to young isochronic controls. Expression of complex IV followed a similar pattern: young heterochronic mice had a trend for lower expression compared to young isochronic controls. Additionally, respirometric analyses indicate that young heterochronic mice had significantly lower complex I, complex I + II, and maximal mitochondrial respiration and a trend for lower complex II-driven respiration compared to young isochronic controls. Interestingly, we did not observe significant improvements in old heterochronic mice compared to old isochronic controls, demonstrating the profound deleterious effects of circulating factors from old mice on mitochondrial structure and function. We also found no significant differences between the young and old heterochronic mice, demonstrating that circulating factors can be a driver of age-related differences in mitochondrial structure and function.

scholarly journals The Interplay between Mitochondrial Morphology and Myomitokines in Aging Sarcopenia

2020 ◽  
Vol 22 (1) ◽  
pp. 91
Author(s):  
Vanina Romanello
Keyword(s):  
Mitochondrial Dysfunction ◽  
Poor Quality ◽  
Whole Body ◽  
Fibroblast Growth Factor 21 ◽  
Mitochondrial Morphology ◽  
Mass Force ◽  
Major Mechanism ◽  
Muscle Aging ◽  
And Function

Sarcopenia is a chronic disease characterized by the progressive loss of skeletal muscle mass, force, and function during aging. It is an emerging public problem associated with poor quality of life, disability, frailty, and high mortality. A decline in mitochondria quality control pathways constitutes a major mechanism driving aging sarcopenia, causing abnormal organelle accumulation over a lifetime. The resulting mitochondrial dysfunction in sarcopenic muscles feedbacks systemically by releasing the myomitokines fibroblast growth factor 21 (FGF21) and growth and differentiation factor 15 (GDF15), influencing the whole-body homeostasis and dictating healthy or unhealthy aging. This review describes the principal pathways controlling mitochondrial quality, many of which are potential therapeutic targets against muscle aging, and the connection between mitochondrial dysfunction and the myomitokines FGF21 and GDF15 in the pathogenesis of aging sarcopenia.

Mitochondrial Morphology and Function

Muscle ◽  
2012 ◽  
pp. 217-229
Author(s):  
Fabio Di Lisa ◽  
Luca Scorrano
Keyword(s):  
Mitochondrial Morphology ◽  
And Function

scholarly journals Analysis of mitochondrial morphology and function with novel fixable fluorescent stains.

1996 ◽  
Vol 44 (12) ◽  
pp. 1363-1372 ◽  
Author(s):  
M Poot ◽  
Y Z Zhang ◽  
J A Krämer ◽  
K S Wells ◽  
L J Jones ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Epifluorescence Microscopy ◽  
Mitochondrial Morphology ◽  
Microtubule Network ◽  
Multiple Features ◽  
Permeabilized Cells ◽  
Dye Staining ◽  
And Function

Investigation of mitochondrial morphology and function has been hampered because photostable, mitochondrion-specific stains that are retained in fixed, permeabilized cells have not been available. We found that in live cell preparations, the CMXRos and H2-CMXRos dyes were more photostable than rhodamine 123. In addition, fluorescence and morphology of mitochondria stained with the CMXRos and CMXRos-H2 dyes were preserved even after formaldehyde fixation and acetone permeabilization. Using epifluorescence microscopy, we showed that CMXRos and H2-CMXRos dye fluorescence fully co-localized with antibodies to subunit I of cytochrome c oxidase, indicating that the dyes specifically stain mitochondria. Confocal microscopy of these mitochondria yielded colored banding patterns, suggesting that these dyes and the mitochondrial enzyme localize to different suborganellar regions. Therefore, these stains provide powerful tools for detailed analysis of mitochondrial fine structure. We also used poisons that decrease mitochondrial membrane potential and an inhibitor of respiration complex II to show by flow cytometry that the fluorescence intensity of CMXRos and H2-CMXRos dye staining responds to changes in mitochondrial membrane potential and function. Hence, CMXRos has the potential to monitor changes in mitochondrial function. In addition, CMXRos staining was used in conjunction with spectrally distinct fluorescent probes for the cell nucleus and the microtubule network to concomitantly evaluate multiple features of cell morphology.

scholarly journals MARCH‐V is a novel mitofusin 2‐ and Drp1‐binding protein able to change mitochondrial morphology

EMBO Reports ◽  
2006 ◽  
Vol 7 (10) ◽  
pp. 1019-1022 ◽  
Author(s):  
Nobuhiro Nakamura ◽  
Yasuo Kimura ◽  
Masaki Tokuda ◽  
Shinji Honda ◽  
Shigehisa Hirose
Keyword(s):  
Binding Protein ◽  
Mitochondrial Morphology ◽  
Mitofusin 2
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