Uncovering the important role of mitochondrial dynamics in oogenesis: impact on fertility and metabolic disorder transmission

Author(s):  
Marcos Roberto Chiaratti
Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Srikanth Elesela ◽  
Nicholas W. Lukacs

Viral diseases account for an increasing proportion of deaths worldwide. Viruses maneuver host cell machinery in an attempt to subvert the intracellular environment favorable for their replication. The mitochondrial network is highly susceptible to physiological and environmental insults, including viral infections. Viruses affect mitochondrial functions and impact mitochondrial metabolism, and innate immune signaling. Resurgence of host-virus interactions in recent literature emphasizes the key role of mitochondria and host metabolism on viral life processes. Mitochondrial dysfunction leads to damage of mitochondria that generate toxic compounds, importantly mitochondrial DNA, inducing systemic toxicity, leading to damage of multiple organs in the body. Mitochondrial dynamics and mitophagy are essential for the maintenance of mitochondrial quality control and homeostasis. Therefore, metabolic antagonists may be essential to gain a better understanding of viral diseases and develop effective antiviral therapeutics. This review briefly discusses how viruses exploit mitochondrial dynamics for virus proliferation and induce associated diseases.


Antioxidants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 522 ◽  
Author(s):  
Wang ◽  
Xiao ◽  
Huang ◽  
Liu

In this study, cell death induced by the oxidant tert-butylhydroperoxide (tBH) was observed in U2OS cells; this phenotype was rescued by Syntaxin 17 (STX17) knockout (KO) but the mechanism is unknown. STX17 plays dual roles in autophagosome–lysosome fusion and mitochondrial fission. However, the contribution of the two functions of STX17 to apoptosis has not been extensively studied. Here, we sought to dissect the dual roles of STX17 in oxidative-stress-induced apoptosis by taking advantage of STX17 knockout cells and an autophagosome–lysosome fusion defective mutant of STX17. We generated STX17 knockout U2OS cells using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system and the STX17 knockout cells were reconstituted with wild-type STX17 and its autophagosome–lysosome fusion defective mutant. Autophagy was assessed by autophagic flux assay, Monomer red fluorescent protein (mRFP)–GFP–LC3 assay and protease protection assay. Golgi, endoplasmic reticulum (ER)/ER–Golgi intermediate compartment (ERGIC) and mitochondrial dynamics were examined by staining the different indicator proteins. Apoptosis was evaluated by caspase cleavage assay. The general reactive oxygen species (ROS) were detected by flow cytometry. In STX17 complete knockout cells, sealed autophagosomes were efficiently formed but their fusion with lysosomes was less defective. The fusion defect was rescued by wild-type STX17 but not the autophagosome–lysosome fusion defective mutant. No obvious defects in Golgi, ERGIC or ER dynamics were observed. Mitochondria were significantly elongated, supporting a role of STX17 in mitochondria fission and the elongation caused by STX17 KO was reversed by the autophagosome–lysosome fusion defective mutant. The clearance of protein aggregation was compromised, correlating with the autophagy defect but not with mitochondrial dynamics. This study revealed a mixed role of STX17 in autophagy, mitochondrial dynamics and oxidative stress response. STX17 knockout cells were highly resistant to oxidative stress, largely due to the function of STX17 in mitochondrial fission rather than autophagy.


Diabetologia ◽  
2021 ◽  
Author(s):  
Yukina Takeichi ◽  
Takashi Miyazawa ◽  
Shohei Sakamoto ◽  
Yuki Hanada ◽  
Lixiang Wang ◽  
...  

Abstract Aims/hypothesis Mitochondria are highly dynamic organelles continuously undergoing fission and fusion, referred to as mitochondrial dynamics, to adapt to nutritional demands. Evidence suggests that impaired mitochondrial dynamics leads to metabolic abnormalities such as non-alcoholic steatohepatitis (NASH) phenotypes. However, how mitochondrial dynamics are involved in the development of NASH is poorly understood. This study aimed to elucidate the role of mitochondrial fission factor (MFF) in the development of NASH. Methods We created mice with hepatocyte-specific deletion of MFF (MffLiKO). MffLiKO mice fed normal chow diet (NCD) or high-fat diet (HFD) were evaluated for metabolic variables and their livers were examined by histological analysis. To elucidate the mechanism of development of NASH, we examined the expression of genes related to endoplasmic reticulum (ER) stress and lipid metabolism, and the secretion of triacylglycerol (TG) using the liver and primary hepatocytes isolated from MffLiKO and control mice. Results MffLiKO mice showed aberrant mitochondrial morphologies with no obvious NASH phenotypes during NCD, while they developed full-blown NASH phenotypes in response to HFD. Expression of genes related to ER stress was markedly upregulated in the liver from MffLiKO mice. In addition, expression of genes related to hepatic TG secretion was downregulated, with reduced hepatic TG secretion in MffLiKO mice in vivo and in primary cultures of MFF-deficient hepatocytes in vitro. Furthermore, thapsigargin-induced ER stress suppressed TG secretion in primary hepatocytes isolated from control mice. Conclusions/interpretation We demonstrated that ablation of MFF in liver provoked ER stress and reduced hepatic TG secretion in vivo and in vitro. Moreover, MffLiKO mice were more susceptible to HFD-induced NASH phenotype than control mice, partly because of ER stress-induced apoptosis of hepatocytes and suppression of TG secretion from hepatocytes. This study provides evidence for the role of mitochondrial fission in the development of NASH. Graphical abstract


Author(s):  
Minsoo Kang ◽  
Sun Kyoung Han ◽  
Suhyun Kim ◽  
Sungyeon Park ◽  
Yerin Jo ◽  
...  

Abstract Hepatic gluconeogenesis is the central pathway for glucose generation in the body. The imbalance between glucose synthesis and uptake leads to metabolic diseases such as obesity, diabetes, and cardiovascular diseases. Small leucine zipper protein (sLZIP) is an isoform of LZIP and it mainly functions as a transcription factor. Although sLZIP is known to regulate the transcription of genes involved in various cellular processes, the role of sLZIP in hepatic glucose metabolism is not known. In this study, we investigated the regulatory role of sLZIP in hepatic gluconeogenesis and its involvement in metabolic disorder. We found that sLZIP expression was elevated during glucose starvation, leading to the promotion of phosphoenolpyruvate carboxylase and glucose-6-phosphatase expression in hepatocytes. However, sLZIP knockdown suppressed the expression of the gluconeogenic enzymes under low glucose conditions. sLZIP also enhanced glucose production in the human liver cells and mouse primary hepatic cells. Fasting-induced cyclic adenosine monophosphate impeded sLZIP degradation. Results of glucose and pyruvate tolerance tests showed that sLZIP transgenic mice exhibited abnormal blood glucose metabolism. These findings suggest that sLZIP is a novel regulator of gluconeogenic enzyme expression and plays a role in blood glucose homeostasis during starvation.


Author(s):  
Hanaa H. Ahmed ◽  
Fatehya M Metwally ◽  
Hend Rashad ◽  
Asmaa M Zaazaa

<p>ABSTRACT<br />Objective: The goal of the present study was to examine the viability of Morus alba (M. alba) ethanolic extract in repression of obesity-associated<br />hepatic steatosis and related metabolic disorder; dyslipidemia, hyperinsulinemia, and glycemic status.<br />Methods: Adult female albino rats were randomly assigned into four groups, eight rats each as follows: Group (1) control group received standard<br />rodent diet for 24 weeks. The other three groups administered high cholesterol diet for 12 weeks and served as obese group, M. alba-treated group,<br />and simvastatin-treated group.<br />Results: The current results showed an increment in thoracic circumference (TCX) and abdominal circumferences (AC) as well as body mass index<br />(BMI) in obese group. In addition, dyslipidemia, hyperinsulinemia, hyperglycemia, and insulin resistance have been elucidated in obese group.<br />Moreover, hepatic malondialdehyde (MDA), nitric oxide (NO), serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and bilirubin<br />values were significantly increased in obese groups versus control group. On the other hand, administration of ethanolic extract of Morus alba or<br />simvastatin could significantly lessen BMI and in addition to improve dyslipidemia in obese group. Glucose, insulin levels, and insulin resistance value<br />in serum samples demonstrated a significant reduction in obese group upon treatment with M. alba ethanolic extract or simvastatin. Furthermore,<br />noticeable depletion in hepatic MDA, NO contents, serum ALT, AST activities, and serum bilirubin level was recorded as a result of treatment with<br />either ethanolic extract of M. alba or simvastatin. Histopathological examination of liver tissue showed ballooning degeneration in the hepatocytes<br />(hepatic steatosis) associated with inflammatory cells penetration in portal zone in obese group. Meanwhile, the treatment of obese groups with<br />ethanolic extract of M. alba or simvastatin was found to restore the structural organization of the liver.<br />Conclusion: The present findings provide a novel aspect for understanding of the role of M. alba against obesity-associated liver diseases and related<br />metabolic disorder. The mechanisms underlying these effects seem to depend on the hypolipidemic potential, anti-inflammatory property, and<br />antioxidant activity of its phytochemicals.<br />Keywords: Obesity, Morus alba, Dyslipidemia, Hyperinsulinemia, Hyperglycemia, Hepatic steatosis.</p>


2009 ◽  
Vol 109 ◽  
pp. 153-159 ◽  
Author(s):  
Xinglong Wang ◽  
Bo Su ◽  
Ling Zheng ◽  
George Perry ◽  
Mark A. Smith ◽  
...  

2021 ◽  
Vol 22 (23) ◽  
pp. 12775
Author(s):  
Isabel Carrascoso ◽  
Beatriz Ramos Velasco ◽  
José M. Izquierdo

T-cell intracellular antigen 1 (TIA1) is a multifunctional RNA-binding protein involved in regulating gene expression and splicing during development and in response to environmental stress, to maintain cell homeostasis and promote survival. Herein, we used TIA1-deficient murine embryonic fibroblasts (MEFs) to study their role in mitochondria homeostasis. We found that the loss of TIA1 was associated with changes in mitochondrial morphology, promoting the appearance of elongated mitochondria with heterogeneous cristae density and size. The proteomic patterns of TIA1-deficient MEFs were consistent with expression changes in molecular components related to mitochondrial dynamics/organization and respiration. Bioenergetics analysis illustrated that TIA1 deficiency enhances mitochondrial respiration. Overall, our findings shed light on the role of TIA1 in mitochondrial dynamics and highlight a point of crosstalk between potential pro-survival and pro-senescence pathways.


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