scholarly journals IGF1R Deficiency Modulates Brain Signaling Pathways and Disturbs Mitochondria and Redox Homeostasis

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 158
Author(s):  
Susana Cardoso ◽  
Icíar López ◽  
Sergio Piñeiro-Hermida ◽  
José Pichel ◽  
Paula Moreira
Keyword(s):  
Signaling Pathways ◽  
Mitochondrial Dynamics ◽  
Redox Homeostasis ◽  
Mitochondrial Respiratory Chain ◽  
Related Factor ◽  
Respiratory Chain Complexes ◽  
Protein Levels ◽  
Chain Complexes ◽  
The Impact ◽  
The Brain

Insulin-like growth factor 1 receptor (IGF1R)-mediated signaling pathways modulate important neurophysiological aspects in the central nervous system, including neurogenesis, synaptic plasticity and complex cognitive functions. In the present study, we intended to characterize the impact of IGF1R deficiency in the brain, focusing on PI3K/Akt and MAPK/ERK1/2 signaling pathways and mitochondria-related parameters. For this purpose, we used 13-week-old UBC-CreERT2; Igf1rfl/fl male mice in which Igf1r was conditionally deleted. IGF1R deficiency caused a decrease in brain weight as well as the activation of the IR/PI3K/Akt and inhibition of the MAPK/ERK1/2/CREB signaling pathways. Despite no alterations in the activity of caspases 3 and 9, a significant alteration in phosphorylated GSK3β and an increase in phosphorylated Tau protein levels were observed. In addition, significant disturbances in mitochondrial dynamics and content and altered activity of the mitochondrial respiratory chain complexes were noticed. An increase in oxidative stress, characterized by decreased nuclear factor E2-related factor 2 (NRF2) protein levels and aconitase activity and increased H2O2 levels were also found in the brain of IGF1R-deficient mice. Overall, our observations confirm the complexity of IGF1R in mediating brain signaling responses and suggest that its deficiency negatively impacts brain cells homeostasis and survival by affecting mitochondria and redox homeostasis.

scholarly journals Selective and Reversible Disruption of Mitochondrial Inner Membrane Protein Complexes by Lipophilic Cations

2021 ◽  
Author(s):  
Anezka Kafkova ◽  
Lisa Tilokani ◽  
Filip Trčka ◽  
Veronika Šrámková ◽  
Marie Vancová ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Respiratory Chain ◽  
Mitochondrial Membrane ◽  
Mitochondrial Morphology ◽  
Respiratory Chain Complexes ◽  
Inner Membrane ◽  
Protein Levels ◽  
Mitochondrial Inner Membrane ◽  
Chain Complexes ◽  
The Impact

ABSTRACTMitochondria represent an attractive drug target in the treatment of many diseases. One of the most commonly used approaches to deliver therapeutics specifically into mitochondria is their conjugation to the triphenylphosphonium (TPP) moiety. While the TPP molecule is often regarded as biologically inert, there is evidence that the moiety itself has a significant impact on the activity of mitochondrial respiratory chain complexes.We studied the impact of a subchronic exposure of C2C12 mouse myoblasts to a set of TPP derivatives. Our results show that the alkyl-TPP cause dose- and hydrophobicity-dependent alterations of mitochondrial morphology and a selective decrease in the amounts of mitochondrial inner membrane (but not outer membrane) proteins including structural subunits of the respiratory chain complexes (such as MT-CO1 of complex IV or NDUFB8 of complex I), as well as components of the mitochondrial calcium uniporter complex (MCUC). The treatment with alkyl-TPP additionally resulted in OPA1-cleavage. Both the structural and functional effects of alkyl-TPP were found to be reversible. A similar effect was observed with the mitochondria-targeted antioxidant MitoQ. We further show that this effect on protein levels cannot be explained solely by a decrease in mitochondrial membrane potential.We conclude that TPP derivatives negatively affect mitochondrial structure and function at least in part through their effect on selective mitochondrial membrane protein levels via a reversible controlled process.

scholarly journals Assembly factors monitor sequential hemylation of cytochrome b to regulate mitochondrial translation

2014 ◽  
Vol 205 (4) ◽  
pp. 511-524 ◽  
Author(s):  
Markus Hildenbeutel ◽  
Eric L. Hegg ◽  
Katharina Stephan ◽  
Steffi Gruschke ◽  
Brigitte Meunier ◽  
...  
Keyword(s):  
Electron Transport ◽  
Cytochrome B ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Mitochondrial Translation ◽  
Respiratory Chain Complexes ◽  
Mitochondrial Inner Membrane ◽  
Sequence Of Events ◽  
Chain Complexes ◽  
Assembly Factors

Mitochondrial respiratory chain complexes convert chemical energy into a membrane potential by connecting electron transport with charge separation. Electron transport relies on redox cofactors that occupy strategic positions in the complexes. How these redox cofactors are assembled into the complexes is not known. Cytochrome b, a central catalytic subunit of complex III, contains two heme bs. Here, we unravel the sequence of events in the mitochondrial inner membrane by which cytochrome b is hemylated. Heme incorporation occurs in a strict sequential process that involves interactions of the newly synthesized cytochrome b with assembly factors and structural complex III subunits. These interactions are functionally connected to cofactor acquisition that triggers the progression of cytochrome b through successive assembly intermediates. Failure to hemylate cytochrome b sequesters the Cbp3–Cbp6 complex in early assembly intermediates, thereby causing a reduction in cytochrome b synthesis via a feedback loop that senses hemylation of cytochrome b.

scholarly journals Mitochondrial Function in Peripheral Blood Mononuclear Cells (PBMC) Is Enhanced, Together with Increased Reactive Oxygen Species, in Severe Asthmatic Patients in Exacerbation

2019 ◽  
Vol 8 (10) ◽  
pp. 1613 ◽  
Author(s):  
Ederlé ◽  
Charles ◽  
Khayath ◽  
Poirot ◽  
Meyer ◽  
...  
Keyword(s):  
Mononuclear Cells ◽  
Mitochondrial Respiratory Chain ◽  
Ros Production ◽  
Oxygen Species ◽  
Respiratory Chain Complexes ◽  
Peripheral Blood Mononuclear ◽  
Asthmatic Patients ◽  
Chain Complexes ◽  
Severe Asthmatic ◽  
Blood Mononuclear Cells

asthma is a chronic inflammatory lung syndrome with an increasing prevalence and a rare but significant risk of death. Its pathophysiology is complex, and therefore we investigated at the systemic level a potential implication of oxidative stress and of peripheral blood mononuclear cells’ (PBMC) mitochondrial function. Twenty severe asthmatic patients with severe exacerbation (GINA 4–5) and 20 healthy volunteers participated at the study. Mitochondrial respiratory chain complexes activities using different substrates and reactive oxygen species (ROS) production were determined in both groups by high-resolution respirometry and electronic paramagnetic resonance, respectively. Healthy PBMC were also incubated with a pool of plasma of severe asthmatics or healthy controls. Mitochondrial respiratory chain complexes activity (+52.45%, p = 0.015 for VADP) and ROS production (+34.3%, p = 0.02) were increased in asthmatic patients. Increased ROS did not originate mainly from mitochondria. Plasma of severe asthmatics significantly increased healthy PBMC mitochondrial dioxygen consumption (+56.8%, p = 0.031). In conclusion, such asthma endotype, characterized by increased PMBCs mitochondrial oxidative capacity and ROS production likely related to a plasma constituent, may reflect activation of the immune system. Further studies are needed to determine whether increased PBMC mitochondrial respiration might have protective effects, opening thus new therapeutic approaches.

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