scholarly journals Depletion of Bcl-xL Impairs Mitochondrial Motility in Primary Hippocampal Neurons

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 908-908
Author(s):  
Joseph Jansen ◽  
Emma Amjad ◽  
Madison Scott ◽  
Allison Stumpf ◽  
Kimberly Lackey ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Synapse Formation ◽  
Mitochondrial Dynamics ◽  
B Cell Lymphoma ◽  
University Of Alabama ◽  
National Academy Of Sciences ◽  
Branching Points ◽  
Primary Hippocampal Neurons ◽  
Mitochondrial Motility ◽  
Increased Susceptibility

Abstract Objectives B-cell lymphoma-extra large (Bcl-xL) is a pro-survival protein localized to mitochondria and is also reported to support brain function by enhancing neuronal energy metabolism and synapse formation. We have previously shown that Bcl-xL is required for neurite outgrowth, and neurons lacking Bcl-xL were susceptible against neurotoxic challenges. In this study, we hypothesized that Bcl-xL supports maintaining neurite ATP by regulating mitochondrial motility. We thus tested if Bcl-xL depletion altered normal mitochondrial dynamics, neuronal energy retention, and neurite morphology. Methods Primary hippocampal neurons were transduced with either Bcl-xL shRNA or scrambled shRNA for 3 weeks. Mitochondria were labeled using mito-RFP BacMam2.0 and image sequences were obtained. Mitochondria motility parameters were quantified using KymoAnalyzer. Local ATP/ADP ratio was analyzed applying PercevalHR fluorescence biosensor, and neurite branches were quantified using Sholl analysis. We further tested viability of neurons against excitotoxicity applying calcein and propioduim iodin staining. Results Primary hippocampal neurons transduced with Bcl-xL shRNA decreased antero- and retrograde movement of mitochondria, lowered ATP/ADP ratio in neurites, and decreased length of neurites and number of branching points. Failure of achieving neurite complexity increased susceptibility of neurons to glutamate-induced excitotoxicity. Conclusions Primary hippocampal neurons transduced with Bcl-xL shRNA decreased antero- and retrograde movement of mitochondria, lowered ATP/ADP ratio in neurites, and decreased length of neurites and number of branching points. Failure of achieving neurite complexity increased susceptibility of neurons to glutamate-induced excitotoxicity. Funding Sources RGC Program (University of Alabama) Crenshaw Research Fund (University of Alabama) Sigma Xi Grants in Aid of Research (The National Academy of Sciences).

scholarly journals Bcl-xL Is Required by Primary Hippocampal Neurons during Development to Support Local Energy Metabolism at Neurites

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 772
Author(s):  
Joseph Jansen ◽  
Madison Scott ◽  
Emma Amjad ◽  
Allison Stumpf ◽  
Kimberly H. Lackey ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Hippocampal Neurons ◽  
Synapse Formation ◽  
Mitochondrial Protein ◽  
B Cell Lymphoma ◽  
Protective Role ◽  
Energy Deficit ◽  
Local Energy ◽  
Branching Points ◽  
Primary Hippocampal Neurons

B-cell lymphoma-extra large (Bcl-xL) is a mitochondrial protein known to inhibit mitochondria-dependent intrinsic apoptotic pathways. An increasing number of studies have demonstrated that Bcl-xL is critical in regulating neuronal energy metabolism and has a protective role in pathologies associated with an energy deficit. However, it is less known how Bcl-xL regulates physiological processes of the brain. In this study, we hypothesize that Bcl-xL is required for neurite branching and maturation during neuronal development by improving local energy metabolism. We found that the absence of Bcl-xL in rat primary hippocampal neurons resulted in mitochondrial dysfunction. Specifically, the ATP/ADP ratio was significantly decreased in the neurites of Bcl-xL depleted neurons. We further found that neurons transduced with Bcl-xL shRNA or neurons treated with ABT-263, a pharmacological inhibitor of Bcl-xL, showed impaired mitochondrial motility. Neurons lacking Bcl-xL had significantly decreased anterograde and retrograde movement of mitochondria and an increased stationary mitochondrial population when Bcl-xL was depleted by either means. These mitochondrial defects, including loss of ATP, impaired normal neurite development. Neurons lacking Bcl-xL showed significantly decreased neurite arborization, growth and complexity. Bcl-xL depleted neurons also showed impaired synapse formation. These neurons showed increased intracellular calcium concentration and were more susceptible to excitotoxic challenge. Bcl-xL may support positioning of mitochondria at metabolically demanding regions of neurites like branching points. Our findings suggest a role for Bcl-xL in physiological regulation of neuronal growth and development.

scholarly journals Vitamin E Prevents ΔN-Bcl-xL-associate Mitochondrial Dysfunction in Primary Hippocampal Neurons (P14-024-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Han-A Park ◽  
Nelli Mnatsakanyan ◽  
Katheryn Broman ◽  
Elizabeth Jonas
Keyword(s):  
Oxidative Stress ◽  
Vitamin E ◽  
Mitochondrial Dysfunction ◽  
Neuronal Death ◽  
Hippocampal Neurons ◽  
Synapse Formation ◽  
B Cell Lymphoma ◽  
Redox Status ◽  
Mitochondrial Potential ◽  
Primary Hippocampal Neurons

Abstract Objectives B-cell lymphoma-extra large (Bcl-xL) is a pro-survival protein localized to mitochondria. Bcl-xL is reported to support brain function by enhancing neuronal energy metabolism, synapse formation, and neurite outgrowth. However, under exposure to excitotoxic stimulation and subsequent oxidative stress, Bcl-xL undergoes caspase dependent cleavage to ∆N-Bcl-xL. Accumulation of ∆N-Bcl-xL is associated with neuronal death; thus, approaches that prevent ∆N-Bcl-xL accumulation protect neurons from excitotoxic insult. In this study, we hypothesize that ∆N-Bcl-xL formation is regulated by redox status in mitochondria. We thus tested if production of ∆N-Bcl-xL can be inhibited by the fat-soluble antioxidant α-tocotrienol (TCT) given its ability to scavenge free radicals produced in the mitochondrial membrane. Methods Primary hippocampal neurons were treated with α-TCT, glutamate, or a combination of both, and mitochondrial oxidative stress, mitochondrial potential, caspase activity, and ∆N-Bcl-xL protein levels were quantified. Results Glutamate caused abnormalities in mitochondrial function leading to neuronal death. The antioxidant α-TCT protected neurons from glutamate-induced mitochondrial dysfunction and cytotoxicity. α-TCT treatment protected against cleavage of full length anti-apoptotic Bcl-xL to form pro-death ∆N-Bcl-xL. α-TCT significantly attenuated glutamate-induced reactive oxygen species (ROS) formation, caspase 3 activation and ∆N-Bcl-xL formation at mitochondria. Conclusions Our data suggests that oxidative stress production during excitotoxicity is responsible for the formation of ∆N-Bcl-xL. Thus, application of a lipophilic antioxidant such as vitamin E is neuroprotective by improving mitochondrial redox status and preventing production of neurotoxic ∆N-Bcl-xL. Funding Sources -NINDS, RO1 -University of Alabama, RGC internal grant.

scholarly journals Alpha-Tocotrienol Prevents Oxidative Stress-Mediated Post-Translational Cleavage of Bcl-xL in Primary Hippocampal Neurons

2019 ◽  
Vol 21 (1) ◽  
pp. 220 ◽  
Author(s):  
Han-A Park ◽  
Nelli Mnatsakanyan ◽  
Katheryn Broman ◽  
Abigail U. Davis ◽  
Jordan May ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Function ◽  
Hippocampal Neurons ◽  
Mitochondrial Membrane ◽  
Antioxidant Properties ◽  
B Cell Lymphoma ◽  
Atp Depletion ◽  
Primary Hippocampal Neurons

B-cell lymphoma-extra large (Bcl-xL) is an anti-apoptotic member of the Bcl2 family of proteins, which supports neurite outgrowth and neurotransmission by improving mitochondrial function. During excitotoxic stimulation, however, Bcl-xL undergoes post-translational cleavage to ∆N-Bcl-xL, and accumulation of ∆N-Bcl-xL causes mitochondrial dysfunction and neuronal death. In this study, we hypothesized that the generation of reactive oxygen species (ROS) during excitotoxicity leads to formation of ∆N-Bcl-xL. We further proposed that the application of an antioxidant with neuroprotective properties such as α-tocotrienol (TCT) will prevent ∆N-Bcl-xL-induced mitochondrial dysfunction via its antioxidant properties. Primary hippocampal neurons were treated with α-TCT, glutamate, or a combination of both. Glutamate challenge significantly increased cytosolic and mitochondrial ROS and ∆N-Bcl-xL levels. ∆N-Bcl-xL accumulation was accompanied by intracellular ATP depletion, loss of mitochondrial membrane potential, and cell death. α-TCT prevented loss of mitochondrial membrane potential in hippocampal neurons overexpressing ∆N-Bcl-xL, suggesting that ∆N-Bcl-xL caused the loss of mitochondrial function under excitotoxic conditions. Our data suggest that production of ROS is an important cause of ∆N-Bcl-xL formation and that preventing ROS production may be an effective strategy to prevent ∆N-Bcl-xL-mediated mitochondrial dysfunction and thus promote neuronal survival.

scholarly journals Roles of Lycopene During Neurite Development of Primary Hippocampal Neurons

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 923-923
Author(s):  
Madison Scott ◽  
Joseph Jansen ◽  
Mary Margaret Hayden ◽  
Katheryn Broman ◽  
Han-A Park
Keyword(s):  
Hippocampal Neurons ◽  
Developmental Disorders ◽  
Neuronal Development ◽  
Stage Iv ◽  
Neurite Growth ◽  
Redox Balance ◽  
University Of Alabama ◽  
Mitochondrial Superoxide ◽  
Primary Hippocampal Neurons ◽  
Neurite Development

Abstract Objectives Neurite outgrowth and branching is critical during neuronal development. Failure to achieve proper neurite complexity is highly associated with developmental disorders. We have previously shown that oxidative stress contributes to alteration of neurite morphology. Therefore, nutrients capable of regulating neuronal redox balance may help maintain normal neurite development. We have recently found that lycopene, a nutritional antioxidant, protects mitochondria by preventing generation of mitochondrial superoxide. In this study, we hypothesize that treatment with lycopene improves development of primary hippocampal neurons under physiological conditions. Methods Primary hippocampal neurons were grown in neurobasal media with or without 0.1 μM lycopene for 1, 3, 5, 7, and 14 days, and imaged using a Zeiss Axio Vert.A1 microscope. Neurons were classified into 4 different categories: stage I, circular and non-polar neurons; stage II, presence of minor neurites without polarity; stage III, neurons with polarity; and stage IV, neurons with dendritic branches. We also performed Sholl analysis to quantify intersections of neurites evaluating neurite complexity. Results Primary hippocampal neurons grown in media containing lycopene showed advanced neuronal development. In particular, lycopene treatment significantly advanced polarity and dendritic arborization in immature neurons. In addition, neurons grown in lycopene showed improved neurite branching at their maturity. Conclusions This study shows that lycopene supports neurite growth and branching during development. Therefore, we suggest novel role of lycopene during physiological development of the brain, or potential therapeutic effect against developmental disorders. Funding Sources RGC Program (University of Alabama) Crenshaw Research Fund (University of Alabama).

scholarly journals Vitamin E Improves Neurite Complexity by Enhancing Mitochondrial Function

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 915-915
Author(s):  
Han-A Park ◽  
Kristi Crowe-White ◽  
Abigail Davis ◽  
Sydni Bannerman ◽  
Garret Burnett ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Vitamin E ◽  
Neurite Outgrowth ◽  
Mitochondrial Function ◽  
Hippocampal Neurons ◽  
Brain Diseases ◽  
Control Group ◽  
University Of Alabama ◽  
Protein Levels ◽  
Primary Hippocampal Neurons

Abstract Objectives Neurite outgrowth is a foundational process in brain development and recovery from brain injury. Assembly of the cytoskeleton and formation of new synapses during neurite outgrowth requires an abundance of energy. We have reported that the mitochondrial protein Bcl-xL is necessary for neurite outgrowth and arborization. However, Bcl-xL undergoes post-translational cleavage during oxidative stress resulting in a product that impairs mitochondrial function. Our recent publication demonstrated that treatment with alpha-tocotrienol, an antioxidant member of the vitamin E family, prevents cleavage of Bcl-xL and protects neurons from oxidative stress. In this study, we hypothesize that treatment with alpha-tocotrienol improves mitochondrial function to support the energy demanding processes of growth and development in the neurons. Methods Primary hippocampal neurons were grown in neurobasal media with or without alpha-tocotrienol for 3 weeks. Then, the number of neurite branches was quantified applying Sholl analysis. We also assayed the ATP/ADP ratio at neurites using the PercevalHR fluorescence biosensor. mRNA and protein levels of total Bcl-xL and cleaved Bcl-xL were measured using real time PCR and immunoblotting. Results Neurons grown with alpha-tocotrienol achieved more advanced neurite complexity than the control group. Treatment with alpha-tocotrienol enhanced both total ATP and local neurite ATP levels in primary hippocampal neurons. Furthermore, we found that alpha-tocotrienol Increased mRNA and protein levels of Bcl-xL without enhancing post-translational cleavage of Bcl-xL, consistent with our previous study. Conclusions Our data show that alpha-tocotrienol improves mitochondria-mediated ATP production by enhancing Bcl-xL to support metabolically demanding processes in neurons. We suggest a novel function of alpha-tocotrienol in normal physiological development of the brain. This study also suggests a potential therapeutic role of alpha-tocotrienol in brain diseases associated with neurite injury. Funding Sources RGC Program (University of Alabama) Crenshaw Research Fund (University of Alabama).

ATRA-induced increase in intracellular Ca2+concentration in primary hippocampal neurons

2010 ◽  
Vol 34 (8) ◽  
pp. S74-S74
Author(s):  
Tingyu Li ◽  
Xiaojuan Zhang ◽  
Xuan Zhang ◽  
Jian Hea ◽  
Yang Bi Youxue Liu ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Primary Hippocampal Neurons

Schisandrin Restores the Amyloid β-Induced Impairments on Mitochondrial Function, Energy Metabolism, Biogenesis, and Dynamics in Rat Primary Hippocampal Neurons

Pharmacology ◽  
2021 ◽  
pp. 1-11
Author(s):  
Zhongyuan Piao ◽  
Lin Song ◽  
Lifen Yao ◽  
Limei Zhang ◽  
Yichan Lu
Keyword(s):  
Energy Metabolism ◽  
Cytochrome C ◽  
Mitochondrial Biogenesis ◽  
Mitochondrial Function ◽  
Hippocampal Neurons ◽  
Citrate Synthase ◽  
Mitochondrial Permeability Transition ◽  
Amyloid Β ◽  
Mitochondrial Functions ◽  
Primary Hippocampal Neurons

Introduction: Schisandrin which is derived from Schisandra chinensis has shown multiple pharmacological effects on various diseases including Alzheimer’s disease (AD). It is demonstrated that mitochondrial dysfunction plays an essential role in the pathogenesis of neurodegenerative disorders. Objective: Our study aims to investigate the effects of schisandrin on mitochondrial functions and metabolisms in primary hippocampal neurons. Methods: In our study, rat primary hippocampal neurons were isolated and treated with indicated dose of amyloid β1–42 (Aβ1–42) oligomer to establish a cell model of AD in vitro. Schisandrin (2 μg/mL) was further subjected to test its effects on mitochondrial function, energy metabolism, mitochondrial biogenesis, and dynamics in the Aβ1–42 oligomer-treated neurons. Results and Conclusions: Our findings indicated that schisandrin significantly alleviated the Aβ1–42 oligomer-induced loss of mitochondrial membrane potential and impaired cytochrome c oxidase activity. Additionally, the opening of mitochondrial permeability transition pore and release of cytochrome c were highly restricted with schisandrin treatment. Alterations in cell viability, ATP production, citrate synthase activity, and the expressions of glycolysis-related enzymes demonstrated the relief of defective energy metabolism in Aβ-treated neurons after the treatment of schisandrin. For mitochondrial biogenesis, elevated expression of peroxisome proliferator-activated receptor γ coactivator along with promoted mitochondrial mass was found in schisandrin-treated cells. The imbalance in the cycle of fusion and fission was also remarkably restored by schisandrin. In summary, this study provides novel mechanisms for the protective effect of schisandrin on mitochondria-related functions.

Neurotrophic Properties of Silexan, an Essential Oil from the Flowers of Lavender-Preclinical Evidence for Antidepressant-Like Properties

2020 ◽  
Vol 54 (01) ◽  
pp. 37-46
Author(s):  
Kristina Friedland ◽  
Giacomo Silani ◽  
Anita Schuwald ◽  
Carola Stockburger ◽  
Egon Koch ◽  
...  
Keyword(s):  
Essential Oil ◽  
Hippocampal Neurons ◽  
Day Treatment ◽  
Neuronal Cell ◽  
Antidepressant Activity ◽  
In Vivo Models ◽  
Antidepressant Effects ◽  
Primary Hippocampal Neurons

Abstract Background Silexan, a special essential oil from flowering tops of lavandula angustifolia, is used to treat subsyndromal anxiety disorders. In a recent clinical trial, Silexan also showed antidepressant effects in patients suffering from mixed anxiety-depression (ICD-10 F41.2). Since preclinical data explaining antidepressant properties of Silexan are missing, we decided to investigate if Silexan also shows antidepressant-like effects in vitro as well as in vivo models. Methods We used the forced swimming test (FST) in rats as a simple behavioral test indicative of antidepressant activity in vivo. As environmental events and other risk factors contribute to depression through converging molecular and cellular mechanisms that disrupt neuronal function and morphology—resulting in dysfunction of the circuitry that is essential for mood regulation and cognitive function—we investigated the neurotrophic properties of Silexan in neuronal cell lines and primary hippocampal neurons. Results The antidepressant activity of Silexan (30 mg/kg BW) in the FST was comparable to the tricyclic antidepressant imipramine (20 mg/kg BW) after 9-day treatment. Silexan triggered neurite outgrowth and synaptogenesis in 2 different neuronal cell models and led to a significant increase in synaptogenesis in primary hippocampal neurons. Silexan led to a significant phosphorylation of protein kinase A and subsequent CREB phosphorylation. Conclusion Taken together, Silexan demonstrates antidepressant-like effects in cellular as well as animal models for antidepressant activity. Therefore, our data provides preclinical evidence for the clinical antidepressant effects of Silexan in patients with mixed depression and anxiety.

scholarly journals BDNF mobilizes synaptic vesicles and enhances synapse formation by disrupting cadherin–β-catenin interactions

2006 ◽  
Vol 174 (2) ◽  
pp. 289-299 ◽  
Author(s):  
Shernaz X. Bamji ◽  
Beatriz Rico ◽  
Nikole Kimes ◽  
Louis F. Reichardt
Keyword(s):  
Synaptic Vesicle ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Synapse Formation ◽  
Time Lapse ◽  
Synapse Density ◽  
Vesicle Mobility ◽  
Small Clusters ◽  
Vertebrate Central Nervous System

Neurons of the vertebrate central nervous system have the capacity to modify synapse number, morphology, and efficacy in response to activity. Some of these functions can be attributed to activity-induced synthesis and secretion of the neurotrophin brain-derived neurotrophic factor (BDNF); however, the molecular mechanisms by which BDNF mediates these events are still not well understood. Using time-lapse confocal analysis, we show that BDNF mobilizes synaptic vesicles at existing synapses, resulting in small clusters of synaptic vesicles “splitting” away from synaptic sites. We demonstrate that BDNF's ability to mobilize synaptic vesicle clusters depends on the dissociation of cadherin–β-catenin adhesion complexes that occurs after tyrosine phosphorylation of β-catenin. Artificially maintaining cadherin–β-catenin complexes in the presence of BDNF abolishes the BDNF-mediated enhancement of synaptic vesicle mobility, as well as the longer-term BDNF-mediated increase in synapse number. Together, this data demonstrates that the disruption of cadherin–β-catenin complexes is an important molecular event through which BDNF increases synapse density in cultured hippocampal neurons.

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