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Mutations in PTEN-induced kinase 1 (PINK1) lead to early onset autosomal recessive Parkinson's disease in humans. In healthy neurons, full-length PINK1 (fPINK1) is post-translationally cleaved into different lower molecular weight forms, and cleaved PINK1 (cPINK1) gets shuttled to the cytosolic compartments to support extra-mitochondrial functions. While numerous studies have exemplified the role of mitochondrially localized PINK1 in modulating mitophagy in oxidatively stressed neurons, little is known regarding the physiological role of cPINK1 in healthy neurons. We have previously shown that cPINK1, but not fPINK1, modulates the neurite outgrowth and the maintenance of dendritic arbors by activating downstream protein kinase A (PKA) signaling in healthy neurons. However, the molecular mechanisms by which cPINK1 promotes neurite outgrowth remain to be elucidated. In this report, we show that cPINK1 supports neuronal development by modulating the expression and extracellular release of brain-derived neurotrophic factor (BDNF). Consistent with this role, we observed a progressive increase in the level of endogenous cPINK1 but not fPINK1 during prenatal and postnatal development of mouse brains and during development in primary cortical neurons. In cultured primary neurons, the pharmacological activation of endogenous PINK1 leads to enhanced downstream PKA activity, subsequent activation of the PKA-modulated transcription factor cAMP response element-binding protein (CREB), increased intracellular production and extracellular release of BDNF, and enhanced activation of the BDNF receptor-TRKβ. Mechanistically, cPINK1-mediated increased dendrite complexity requires the binding of extracellular BDNF to TRKβ. In summary, our data support a physiological role of cPINK1 in stimulating neuronal development by activating the PKA-CREB-BDNF signaling axis in a feedforward loop.
Smijin K. Soman; David Tingle; Raul Y. Dagda; Mariana Torres; Marisela Dagda; Ruben K. Dagda. Cleaved PINK1 induces neuronal plasticity through PKA‐mediated BDNF functional regulation. Journal of Neuroscience Research 2021, 99, 2134 -2155.
AMA StyleSmijin K. Soman, David Tingle, Raul Y. Dagda, Mariana Torres, Marisela Dagda, Ruben K. Dagda. Cleaved PINK1 induces neuronal plasticity through PKA‐mediated BDNF functional regulation. Journal of Neuroscience Research. 2021; 99 (9):2134-2155.
Chicago/Turabian StyleSmijin K. Soman; David Tingle; Raul Y. Dagda; Mariana Torres; Marisela Dagda; Ruben K. Dagda. 2021. "Cleaved PINK1 induces neuronal plasticity through PKA‐mediated BDNF functional regulation." Journal of Neuroscience Research 99, no. 9: 2134-2155.
Alzheimer’s disease (AD) is a neurodegenerative disease characterized by progressive memory loss and cognitive decline. In hippocampal neurons, the pathological features of AD include the accumulation of extracellular amyloid-beta peptide (Aβ) accompanied by oxidative stress, mitochondrial dysfunction, and neuron loss. A decrease in neuroprotective Protein Kinase A (PKA) signaling contributes to mitochondrial fragmentation and neurodegeneration in AD. By associating with the protein scaffold Dual-Specificity Anchoring Protein 1 (D-AKAP1), PKA is targeted to mitochondria to promote mitochondrial fusion by phosphorylating the fission modulator dynamin-related protein 1 (Drp1). We hypothesized that (1) a decrease in the endogenous level of endogenous D-AKAP1 contributes to decreased PKA signaling in mitochondria and that (2) restoring PKA signaling in mitochondria can reverse neurodegeneration and mitochondrial fragmentation in neurons in AD models. Through immunohistochemistry, we showed that endogenous D-AKAP1, but not other mitochondrial proteins, is significantly reduced in primary neurons treated with Aβ42 peptide (10μM, 24 h), and in the hippocampus and cortex from asymptomatic and symptomatic AD mice (5X-FAD). Transiently expressing wild-type, but not a PKA-binding deficient mutant of D-AKAP1, was able to reduce mitochondrial fission, dendrite retraction, and apoptosis in primary neurons treated with Aβ42. Mechanistically, the protective effects of D-AKAP1/PKA are moderated through PKA-mediated phosphorylation of Drp1, as transiently expressing a PKA phosphomimetic mutant of Drp1 (Drp1-S656D) phenocopies D-AKAP1’s ability to reduce Aβ42-mediated apoptosis and mitochondrial fission. Overall, our data suggest that a loss of D-AKAP1/PKA contributes to mitochondrial pathology and neurodegeneration in an in vitro cell culture model of AD.
Tania Das Banerjee; Kelly Reihl; Maryann Swain; Mariana Torres; Ruben K. Dagda. Mitochondrial PKA Is Neuroprotective in a Cell Culture Model of Alzheimer’s Disease. Molecular Neurobiology 2021, 1 -13.
AMA StyleTania Das Banerjee, Kelly Reihl, Maryann Swain, Mariana Torres, Ruben K. Dagda. Mitochondrial PKA Is Neuroprotective in a Cell Culture Model of Alzheimer’s Disease. Molecular Neurobiology. 2021; ():1-13.
Chicago/Turabian StyleTania Das Banerjee; Kelly Reihl; Maryann Swain; Mariana Torres; Ruben K. Dagda. 2021. "Mitochondrial PKA Is Neuroprotective in a Cell Culture Model of Alzheimer’s Disease." Molecular Neurobiology , no. : 1-13.
Cardiotoxin CTII from Naja oxiana cobra venom translocates to the intermembrane space (IMS) of mitochondria to disrupt the structure and function of the inner mitochondrial membrane. At low concentrations, CTII facilitates ATP-synthase activity, presumably via the formation of non-bilayer, immobilized phospholipids that are critical in modulating ATP-synthase activity. In this study, we investigated the effects of another cardiotoxin CTI from Naja oxiana cobra venom on the structure of mitochondrial membranes and on mitochondrial-derived ATP synthesis. By employing robust biophysical methods including 31P-NMR and 1H-NMR spectroscopy, we analyzed the effects of CTI and CTII on phospholipid packing and dynamics in model phosphatidylcholine (PC) membranes enriched with 2.5 and 5.0 mol% of cardiolipin (CL), a phospholipid composition that mimics that in the outer mitochondrial membrane (OMM). These experiments revealed that CTII converted a higher percentage of bilayer phospholipids to a non-bilayer and immobilized state and both cardiotoxins utilized CL and PC molecules to form non-bilayer structures. Furthermore, in order to gain further understanding on how cardiotoxins bind to mitochondrial membranes, we employed molecular dynamics (MD) and molecular docking simulations to investigate the molecular mechanisms by which CTII and CTI interactively bind with an in silico phospholipid membrane that models the composition similar to the OMM. In brief, MD studies suggest that CTII utilized the N-terminal region to embed the phospholipid bilayer more avidly in a horizontal orientation with respect to the lipid bilayer and thereby penetrate at a faster rate compared with CTI. Molecular dynamics along with the Autodock studies identified critical amino acid residues on the molecular surfaces of CTII and CTI that facilitated the long-range and short-range interactions of cardiotoxins with CL and PC. Based on our compiled data and our published findings, we provide a conceptual model that explains a molecular mechanism by which snake venom cardiotoxins, including CTI and CTII, interact with mitochondrial membranes to alter the mitochondrial membrane structure to either upregulate ATP-synthase activity or disrupt mitochondrial function.
Feng Li; Indira H. Shrivastava; Paul Hanlon; Ruben K. Dagda; Edward S. Gasanoff. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins 2020, 12, 425 .
AMA StyleFeng Li, Indira H. Shrivastava, Paul Hanlon, Ruben K. Dagda, Edward S. Gasanoff. Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane. Toxins. 2020; 12 (7):425.
Chicago/Turabian StyleFeng Li; Indira H. Shrivastava; Paul Hanlon; Ruben K. Dagda; Edward S. Gasanoff. 2020. "Molecular Mechanism by which Cobra Venom Cardiotoxins Interact with the Outer Mitochondrial Membrane." Toxins 12, no. 7: 425.
Psychological distress induces oxidative stress and alters mitochondrial metabolism in the nervous and immune systems. Psychological distress promotes alterations in brain metabolism and neurochemistry in wild-type (WT) rats in a similar manner as in Parkinsonian rats lacking endogenous PTEN-induced kinase 1 (PINK1), a serine/threonine kinase mutated in a recessive forms of Parkinson’s disease. PINK1 has been extensively studied in the brain, but its physiological role in peripheral tissues and the extent to which it intersects with the neuroimmune axis is not clear. We surmised that PINK1 modulates the bioenergetics of peripheral blood mononuclear cells (PBMCs) under basal conditions or in situations that promote oxidative stress as psychological distress. By using an XF metabolic bioanalyzer, PINK1-KO-PBMCs showed significantly increased oxidative phosphorylation and basal glycolysis compared to WT cells and correlated with motor dysfunction. In addition, psychological distress enhanced the glycolytic capacity in PINK1-KO-PBMCs but not in WT-PBMCs. The level of antioxidant markers and brain-derived neurotrophic factor were altered in PINK1-KO-PBMCs and by psychological distress. In summary, our data suggest that PINK1 is critical for modulating the bioenergetics and antioxidant responses in PBMCs whereas lack of PINK1 upregulates compensatory glycolysis in response to oxidative stress induced by psychological distress.
Mariana Grigoruţă; Ruben K. Dagda; Ángel G. Díaz-Sánchez; Alejandro Martínez-Martínez. Psychological distress and lack of PINK1 promote bioenergetics alterations in peripheral blood mononuclear cells. Scientific Reports 2020, 10, 1 -14.
AMA StyleMariana Grigoruţă, Ruben K. Dagda, Ángel G. Díaz-Sánchez, Alejandro Martínez-Martínez. Psychological distress and lack of PINK1 promote bioenergetics alterations in peripheral blood mononuclear cells. Scientific Reports. 2020; 10 (1):1-14.
Chicago/Turabian StyleMariana Grigoruţă; Ruben K. Dagda; Ángel G. Díaz-Sánchez; Alejandro Martínez-Martínez. 2020. "Psychological distress and lack of PINK1 promote bioenergetics alterations in peripheral blood mononuclear cells." Scientific Reports 10, no. 1: 1-14.
Psychological distress is a public health issue as it contributes to the development of human diseases including neuropathologies. Parkinson’s disease (PD), a chronic, progressive neurodegenerative disorder, is caused by multiple factors including aging, mitochondrial dysfunction, and/or stressors. In PD, a substantial loss of substantia nigra (SN) neurons leads to rigid tremors, bradykinesia, and chronic fatigue. Several studies have reported that the hypothalamic-pituitary-adrenal (HPA) axis is altered in PD patients, leading to an increase level of cortisol which contributes to neurodegeneration and oxidative stress. We hypothesized that chronic psychological distress induces PD-like symptoms and promotes neurodegeneration in wild-type (WT) rats and exacerbates PD pathology in PINK1 knockout (KO) rats, a well-validated animal model of PD. We measured the bioenergetics profile (oxidative phosphorylation and glycolysis) in the brain by employing an XF24e Seahorse Extracellular Flux Analyzer in young rats subjected to predator-induced psychological distress. In addition, we analyzed anxiety-like behavior, motor function, expression of antioxidant enzymes, mitochondrial content, and neurotrophic factors brain-derived neurotrophic factor (BDNF) in the brain. Overall, we observed that psychological distress diminished up to 50% of mitochondrial respiration and glycolysis in the prefrontal cortex (PFC) derived from both WT and PINK1-KO rats. Mechanistically, the level of antioxidant proteins, mitochondrial content, and BDNF was significantly altered. Finally, psychological distress robustly induced anxiety and Parkinsonian symptoms in WT rats and accelerated certain symptoms of PD in PINK1-KO rats. For the first time, our collective data suggest that psychological distress can phenocopy several aspects of PD neuropathology, disrupt brain energy production, as well as induce ataxia-like behavior.
Mariana Grigoruţă; Alejandro Martínez-Martínez; Raul Y. Dagda; Ruben K. Dagda. Psychological Stress Phenocopies Brain Mitochondrial Dysfunction and Motor Deficits as Observed in a Parkinsonian Rat Model. Molecular Neurobiology 2019, 57, 1781 -1798.
AMA StyleMariana Grigoruţă, Alejandro Martínez-Martínez, Raul Y. Dagda, Ruben K. Dagda. Psychological Stress Phenocopies Brain Mitochondrial Dysfunction and Motor Deficits as Observed in a Parkinsonian Rat Model. Molecular Neurobiology. 2019; 57 (4):1781-1798.
Chicago/Turabian StyleMariana Grigoruţă; Alejandro Martínez-Martínez; Raul Y. Dagda; Ruben K. Dagda. 2019. "Psychological Stress Phenocopies Brain Mitochondrial Dysfunction and Motor Deficits as Observed in a Parkinsonian Rat Model." Molecular Neurobiology 57, no. 4: 1781-1798.
The creation of technology that affords for the design of artificial enzymes is a new branch of biochemical engineering with the objective to solve the looming global catastrophe including food shortages, energy crisis, novel diseases, climate change and environmental degradation. However, the development of science and technology that will lead to the design of artificial enzymes depends on availability of scientists with a broad range of expertise including chemistry and physics of chemical bonding, structural biochemistry of macromolecular interactions, theoretical physics and mathematics with the focus on computer modeling of dynamic docking of macromolecules. Our previous experience in university STEM education led us to conclude that in order to train future scientists with a broad expertise in STEM, it is critical for high school students to learn interdisciplinary concepts of STEM courses at an earlier age. In this article, we describe the first phase of a STEM project that involved introducing students to STEM curriculum designed to steer high school students’ interest towards biochemical engineering and pharmacology. In addition, we present the outline of the STEM curriculum, along with user-friendly tutorials of AutoDock Vina, AutoDock Tools and PyMol programs that we designed to teach secondary STEM students computer modeling and docking of macromolecules. STEM high school students performed multiple exercises to understand how the potential pharmacological agents, cardiotoxins from cobra venom, interact with mitochondrial phospholipids in order to gain a deep understanding of elevated biophysical and biochemical concepts in protein drug interactions with biomembranes. We also present the results of evaluative assessments that tested students’ knowledge and skills that students gained following the completion of our pilot STEM course. In brief, the assessment results showed that the students successfully acquired a high level of understanding in structural biophysics and biochemistry. Importantly, this paper provides strong proof-of-concept that our pilot STEM curriculum can be successfully integrated in the traditional American and Chinese high school classroom. The curriculum and tutorials presented in this article could be used by college and high school teachers and students in STEM classes and to support undergraduate university courses in Pharmacology, Inorganic and Organic Chemistry, Biochemistry and Structural Biology for classroom instructions and homework assignments.
Edward S. Gasanoff; Feng Li; Edward M. George; Ruben K. Dagda. A Pilot STEM Curriculum Designed to Teach High School Students Concepts in Biochemical Engineering and Pharmacology. 2019, 7, 846 -877.
AMA StyleEdward S. Gasanoff, Feng Li, Edward M. George, Ruben K. Dagda. A Pilot STEM Curriculum Designed to Teach High School Students Concepts in Biochemical Engineering and Pharmacology. . 2019; 7 (8):846-877.
Chicago/Turabian StyleEdward S. Gasanoff; Feng Li; Edward M. George; Ruben K. Dagda. 2019. "A Pilot STEM Curriculum Designed to Teach High School Students Concepts in Biochemical Engineering and Pharmacology." 7, no. 8: 846-877.
Cobra venom cardiotoxins (CVCs) can translocate to mitochondria to promote apoptosis by eliciting mitochondrial dysfunction. However, the molecular mechanism(s) by which CVCs are selectively targeted to the mitochondrion to disrupt mitochondrial function remains to be elucidated. By studying cardiotoxin from Naja mossambica mossambica cobra (cardiotoxin VII4), a basic three-fingered S-type cardiotoxin, we hypothesized that cardiotoxin VII4 binds to cardiolipin (CL) in mitochondria to alter mitochondrial structure/function and promote neurotoxicity. By performing confocal analysis, we observed that red-fluorescently tagged cardiotoxin rapidly translocates to mitochondria in mouse primary cortical neurons and in human SH-SY5Y neuroblastoma cells to promote aberrant mitochondrial fragmentation, a decline in oxidative phosphorylation, and decreased energy production. In addition, by employing electron paramagnetic resonance (EPR) and protein nuclear magnetic resonance (¹H-NMR) spectroscopy and phosphorescence quenching of erythrosine in model membranes, our compiled biophysical data show that cardiotoxin VII4 binds to anionic CL, but not to zwitterionic phosphatidylcholine (PC), to increase the permeability and formation of non-bilayer structures in CL-enriched membranes that biochemically mimic the outer and inner mitochondrial membranes. Finally, molecular dynamics simulations and in silico docking studies identified CL binding sites in cardiotoxin VII4 and revealed a molecular mechanism by which cardiotoxin VII4 interacts with CL and PC to bind and penetrate mitochondrial membranes.
Boris Zhang; Feng Li; Zhengyao Chen; Indira H. Shrivastava; Edward S. Gasanoff; Ruben K. Dagda. Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function. Toxins 2019, 11, 152 .
AMA StyleBoris Zhang, Feng Li, Zhengyao Chen, Indira H. Shrivastava, Edward S. Gasanoff, Ruben K. Dagda. Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function. Toxins. 2019; 11 (3):152.
Chicago/Turabian StyleBoris Zhang; Feng Li; Zhengyao Chen; Indira H. Shrivastava; Edward S. Gasanoff; Ruben K. Dagda. 2019. "Naja mossambica mossambica Cobra Cardiotoxin Targets Mitochondria to Disrupt Mitochondrial Membrane Structure and Function." Toxins 11, no. 3: 152.
Protein kinase A (PKA) is a ser/thr kinase that is critical for maintaining essential neuronal functions including mitochondrial homeostasis, bioenergetics, neuronal development, and neurotransmission. The endogenous pool of PKA is targeted to the mitochondrion by forming a complex with the mitochondrial scaffold A-kinase anchoring protein 121 (AKAP121). Enhanced PKA signaling via AKAP121 leads to PKA-mediated phosphorylation of the fission modulator Drp1, leading to enhanced mitochondrial networks and thereby blocking apoptosis against different toxic insults. In this study, we show for the first time that AKAP121/PKA confers neuroprotection in an in vitro model of oxidative stress induced by exposure to excess glutamate. Unexpectedly, treating mouse hippocampal progenitor neuronal HT22 cells with an acute dose or chronic exposure of glutamate robustly elevates PKA signaling, a beneficial compensatory response that is phenocopied in HT22 cells conditioned to thrive in the presence of excess glutamate but not in parental HT22 cells. Secondly, redirecting the endogenous pool of PKA by transiently transfecting AKAP121 or transfecting a constitutively active mutant of PKA targeted to the mitochondrion (OMM-PKA) or of an isoform of AKAP121 that lacks the KH and Tudor domains (S-AKAP84) are sufficient to significantly block cell death induced by glutamate toxicity but not in an oxygen deprivation/reperfusion model. Conversely, transient transfection of HT22 neuronal cells with a PKA-binding-deficient mutant of AKAP121 is unable to protect against oxidative stress induced by glutamate toxicity suggesting that the catalytic activity of PKA is required for AKAP121’s protective effects. Mechanistically, AKAP121 promotes neuroprotection by enhancing PKA-mediated phosphorylation of Drp1 to increase mitochondrial fusion, elevates ATP levels, and elicits an increase in the levels of antioxidants GSH and superoxide dismutase 2 leading to a reduction in the level of mitochondrial superoxide. Overall, our data supports AKAP121/PKA as a new molecular target that confers neuroprotection against glutamate toxicity by phosphorylating Drp1, to stabilize mitochondrial networks and mitochondrial function and to elicit antioxidant responses.
Jingdian Zhang; Jiachun Feng; Di Ma; Feng Wang; Yumeng Wang; Chunxiao Li; Xu Wang; Xiang Yin; Ming Zhang; Ruben K. Dagda; Ying Zhang. Neuroprotective Mitochondrial Remodeling by AKAP121/PKA Protects HT22 Cell from Glutamate-Induced Oxidative Stress. Molecular Neurobiology 2019, 56, 5586 -5607.
AMA StyleJingdian Zhang, Jiachun Feng, Di Ma, Feng Wang, Yumeng Wang, Chunxiao Li, Xu Wang, Xiang Yin, Ming Zhang, Ruben K. Dagda, Ying Zhang. Neuroprotective Mitochondrial Remodeling by AKAP121/PKA Protects HT22 Cell from Glutamate-Induced Oxidative Stress. Molecular Neurobiology. 2019; 56 (8):5586-5607.
Chicago/Turabian StyleJingdian Zhang; Jiachun Feng; Di Ma; Feng Wang; Yumeng Wang; Chunxiao Li; Xu Wang; Xiang Yin; Ming Zhang; Ruben K. Dagda; Ying Zhang. 2019. "Neuroprotective Mitochondrial Remodeling by AKAP121/PKA Protects HT22 Cell from Glutamate-Induced Oxidative Stress." Molecular Neurobiology 56, no. 8: 5586-5607.
Mitochondria are multifaceted organelles that serve to power critical neuronal functions.[…]
Ruben K. Dagda. Role of Mitochondrial Dysfunction in Degenerative Brain Diseases, an Overview. Brain Sciences 2018, 8, 178 .
AMA StyleRuben K. Dagda. Role of Mitochondrial Dysfunction in Degenerative Brain Diseases, an Overview. Brain Sciences. 2018; 8 (10):178.
Chicago/Turabian StyleRuben K. Dagda. 2018. "Role of Mitochondrial Dysfunction in Degenerative Brain Diseases, an Overview." Brain Sciences 8, no. 10: 178.
The gut–brain axis refers to the bidirectional communication between the enteric nervous system and the central nervous system. Mounting evidence supports the premise that the intestinal microbiota plays a pivotal role in its function and has led to the more common and perhaps more accurate term gut–microbiota–brain axis. Numerous studies have identified associations between an altered microbiome and neuroimmune and neuroinflammatory diseases. In most cases, it is unknown if these associations are cause or effect; notwithstanding, maintaining or restoring homeostasis of the microbiota may represent future opportunities when treating or preventing these diseases. In recent years, several studies have identified the diet as a primary contributing factor in shaping the composition of the gut microbiota and, in turn, the mucosal and systemic immune systems. In this review, we will discuss the potential opportunities and challenges with respect to modifying and shaping the microbiota through diet and nutrition in order to treat or prevent neuroimmune and neuroinflammatory disease.
Vincent C. Lombardi; Kenny L. De Meirleir; Krishnamurthy Subramanian; Sam M. Nourani; Ruben K. Dagda; Shannon L. Delaney; András Palotás. Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease. The Journal of Nutritional Biochemistry 2018, 61, 1 -16.
AMA StyleVincent C. Lombardi, Kenny L. De Meirleir, Krishnamurthy Subramanian, Sam M. Nourani, Ruben K. Dagda, Shannon L. Delaney, András Palotás. Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease. The Journal of Nutritional Biochemistry. 2018; 61 ():1-16.
Chicago/Turabian StyleVincent C. Lombardi; Kenny L. De Meirleir; Krishnamurthy Subramanian; Sam M. Nourani; Ruben K. Dagda; Shannon L. Delaney; András Palotás. 2018. "Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease." The Journal of Nutritional Biochemistry 61, no. : 1-16.
Adenosine monophosphate-activated protein kinase (AMPK) is a conserved, redox-activated master regulator of cell metabolism. In the presence of oxidative stress, AMPK promotes cytoprotection by enhancing the conservation of energy by suppressing protein translation and by stimulating autophagy. AMPK interplays with protein kinase A (PKA) to regulate oxidative stress, mitochondrial function, and cell survival. AMPK and dual-specificity A-kinase anchoring protein 1 (D-AKAP1), a mitochondrial-directed scaffold of PKA, interact to regulate mitochondrial function and oxidative stress in cardiac and endothelial cells. Ischemia and diabetes, a chronic disease that increases the onset of cardiovascular diseases, suppress the cardioprotective effects of AMPK and PKA. Here, we review the molecular mechanisms by which AMPK and D-AKAP1/PKA interplay to regulate mitochondrial function, oxidative stress, and signaling pathways that prime endothelial cells, cardiac cells, and neurons for cytoprotection against oxidative stress. We discuss recent literature showing how temporal dynamics and localization of activated AMPK and PKA holoenzymes play a crucial role in governing cellular bioenergetics and cell survival in models of ischemia, cardiovascular diseases, and diabetes. Finally, we propose therapeutic strategies that tout localized PKA and AMPK signaling to reverse mitochondrial dysfunction, oxidative stress, and death of neurons and cardiac and endothelial cells during ischemia and diabetes.
Jingdian Zhang; Yumeng Wang; Xiaofeng Liu; Ruben K. Dagda; Ying Zhang. How AMPK and PKA Interplay to Regulate Mitochondrial Function and Survival in Models of Ischemia and Diabetes. Oxidative Medicine and Cellular Longevity 2017, 2017, 1 -12.
AMA StyleJingdian Zhang, Yumeng Wang, Xiaofeng Liu, Ruben K. Dagda, Ying Zhang. How AMPK and PKA Interplay to Regulate Mitochondrial Function and Survival in Models of Ischemia and Diabetes. Oxidative Medicine and Cellular Longevity. 2017; 2017 ():1-12.
Chicago/Turabian StyleJingdian Zhang; Yumeng Wang; Xiaofeng Liu; Ruben K. Dagda; Ying Zhang. 2017. "How AMPK and PKA Interplay to Regulate Mitochondrial Function and Survival in Models of Ischemia and Diabetes." Oxidative Medicine and Cellular Longevity 2017, no. : 1-12.
Arsenic is a potent cardiovascular toxicant associated with numerous biomarkers of cardiovascular diseases in exposed human populations. Arsenic is also a carcinogen, yet arsenic trioxide is used as a therapeutic agent in the treatment of acute promyelotic leukemia (APL). The therapeutic use of arsenic is limited due to its severe cardiovascular side effects. Many of the toxic effects of arsenic are mediated by mitochondrial dysfunction and related to arsenic’s effect on oxidative stress. Therefore, we investigated the effectiveness of antioxidants against arsenic induced cardiovascular dysfunction. A growing body of evidence suggests that antioxidant phytonutrients may ameliorate the toxic effects of arsenic on mitochondria by scavenging free radicals. This review identifies 21 antioxidants that can effectively reverse mitochondrial dysfunction and oxidative stress in cardiovascular cells and tissues. In addition, we propose that antioxidants have the potential to improve the cardiovascular health of millions of people chronically exposed to elevated arsenic concentrations through contaminated water supplies or used to treat certain types of leukemias. Importantly, we identify conceptual gaps in research and development of new mito-protective antioxidants and suggest avenues for future research to improve bioavailability of antioxidants and distribution to target tissues in order reduce arsenic-induced cardiovascular toxicity in a real-world context.
Clare Pace; Ruben Dagda; Jeff Angermann. Antioxidants Protect against Arsenic Induced Mitochondrial Cardio-Toxicity. Toxics 2017, 5, 38 .
AMA StyleClare Pace, Ruben Dagda, Jeff Angermann. Antioxidants Protect against Arsenic Induced Mitochondrial Cardio-Toxicity. Toxics. 2017; 5 (4):38.
Chicago/Turabian StyleClare Pace; Ruben Dagda; Jeff Angermann. 2017. "Antioxidants Protect against Arsenic Induced Mitochondrial Cardio-Toxicity." Toxics 5, no. 4: 38.
Cardiolipin (CL) is an anionic phospholipid at the inner mitochondrial membrane (IMM) that facilitates the formation of transient non-bilayer (non-lamellar) structures to maintain mitochondrial integrity. CL modulates mitochondrial functions including ATP synthesis. However, the biophysical mechanisms by which CL generates non-lamellar structures and the extent to which these structures contribute to ATP synthesis remain unknown. We hypothesized that CL and ATP synthase facilitate the formation of non-bilayer structures at the IMM to stimulate ATP synthesis. By using 1H NMR and 31P NMR techniques, we observed that increasing the temperature (8 °C to 37 °C), lowering the pH (3.0), or incubating intact mitochondria with CTII - an IMM-targeted toxin that increases the formation of immobilized non-bilayer structures - elevated the formation of non-bilayer structures to stimulate ATP synthesis. The F0 sector of the ATP synthase complex can facilitate the formation of non-bilayer structures as incubating model membranes enriched with IMM-specific phospholipids with exogenous DCCD-binding protein of the F0 sector (DCCD-BPF) elevated the formation of immobilized non-bilayer structures to a similar manner as CTII. Native PAGE assays revealed that CL, but not other anionic phospholipids, specifically binds to DCCD-BPF to promote the formation of stable lipid-protein complexes. Mechanistically, molecular docking studies identified two lipid binding sites for CL in DCCD-BPF. We propose a new model of ATP synthase regulation in which CL mediates the formation of non-bilayer structures that serve to cluster protons and ATP synthase complexes as a mechanism to enhance proton translocation to the F0 sector, and thereby increase ATP synthesis.
Sardar E. Gasanov; Aleksandr A. Kim; Lev S. Yaguzhinsky; Ruben K. Dagda. Non-bilayer structures in mitochondrial membranes regulate ATP synthase activity. Biochimica et Biophysica Acta (BBA) - Biomembranes 2017, 1860, 586 -599.
AMA StyleSardar E. Gasanov, Aleksandr A. Kim, Lev S. Yaguzhinsky, Ruben K. Dagda. Non-bilayer structures in mitochondrial membranes regulate ATP synthase activity. Biochimica et Biophysica Acta (BBA) - Biomembranes. 2017; 1860 (2):586-599.
Chicago/Turabian StyleSardar E. Gasanov; Aleksandr A. Kim; Lev S. Yaguzhinsky; Ruben K. Dagda. 2017. "Non-bilayer structures in mitochondrial membranes regulate ATP synthase activity." Biochimica et Biophysica Acta (BBA) - Biomembranes 1860, no. 2: 586-599.
Mitochondrial Protein Kinase A (PKA) and PTEN‐induced kinase 1 (PINK1), which is linked to Parkinson's disease, are two neuroprotective serine/threonine kinases that regulate dendrite remodeling and mitochondrial function. We have previously shown that PINK1 regulates dendrite morphology by enhancing PKA activity. Here, we show the molecular mechanisms by which PINK1 and PKA in the mitochondrion interact to regulate dendrite remodeling, mitochondrial morphology, content, and trafficking in dendrites. PINK1‐deficient cortical neurons exhibit impaired mitochondrial trafficking, reduced mitochondrial content, fragmented mitochondria, and a reduction in dendrite outgrowth compared to wild‐type neurons. Transient expression of wild‐type, but not a PKA‐binding‐deficient mutant of the PKA‐mitochondrial scaffold dual‐specificity A Kinase Anchoring Protein 1 (D‐AKAP1), restores mitochondrial trafficking, morphology, and content in dendrites of PINK1‐deficient cortical neurons suggesting that recruiting PKA to the mitochondrion reverses mitochondrial pathology in dendrites induced by loss of PINK1. Mechanistically, full‐length and cleaved forms of PINK1 increase the binding of the regulatory subunit β of PKA (PKA/RIIβ) to D‐AKAP1 to enhance the autocatalytic‐mediated phosphorylation of PKA/RIIβ and PKA activity. D‐AKAP1/PKA governs mitochondrial trafficking in dendrites via the Miro‐2/TRAK2 complex and by increasing the phosphorylation of Miro‐2. Our study identifies a new role of D‐AKAP1 in regulating mitochondrial trafficking through Miro‐2, and supports a model in which PINK1 and mitochondrial PKA participate in a similar neuroprotective signaling pathway to maintain dendrite connectivity.
Tania Das Banerjee; Raul Y. Dagda; Marisela Dagda; Charleen T. Chu; Monica Rice; Emmanuel Vázquez-Mayorga; Ruben K. Dagda. PINK1 regulates mitochondrial trafficking in dendrites of cortical neurons through mitochondrial PKA. Journal of Neurochemistry 2017, 142, 545 -559.
AMA StyleTania Das Banerjee, Raul Y. Dagda, Marisela Dagda, Charleen T. Chu, Monica Rice, Emmanuel Vázquez-Mayorga, Ruben K. Dagda. PINK1 regulates mitochondrial trafficking in dendrites of cortical neurons through mitochondrial PKA. Journal of Neurochemistry. 2017; 142 (4):545-559.
Chicago/Turabian StyleTania Das Banerjee; Raul Y. Dagda; Marisela Dagda; Charleen T. Chu; Monica Rice; Emmanuel Vázquez-Mayorga; Ruben K. Dagda. 2017. "PINK1 regulates mitochondrial trafficking in dendrites of cortical neurons through mitochondrial PKA." Journal of Neurochemistry 142, no. 4: 545-559.
Mitochondria are organelles that regulate essential eukaryotic functions including generating energy, sequestering excess calcium, and modulating cell survival. In order for neurons to thrive, mitochondria have to be continuously replenished by maintaining autophagic-lysosomal mediated degradation of mitochondria (mitophagy) and mitochondrial biogenesis. While a plethora of image- and biochemical-based techniques have been developed for measuring autophagy (macroautophagy) in eukaryotic cells, the molecular toolbox for quantifying and assessing mitophagy in neurons continues to evolve. Compared to proliferating cells, quantifying mitophagy in neurons poses a technical challenge given that mitochondria are predominantly present in neurites (axons and dendrites) and are highly dynamic. In this chapter, we provide a brief overview on mitophagy and provide a list of validated fluorescence- and biochemistry-based techniques used for assessing mitophagy in neuronal cells and primary neurons. Secondly, we provide comprehensive guidelines for interpreting steady-state levels of mitophagy and mitophagic flux in neurons using modern fluorescence- and biochemistry-based techniques. Finally, we provide a comprehensive list of common pitfalls to avoid when assessing mitophagy and offer practical solutions to overcome technical issues.
Ruben K. Dagda; Monica Rice. Protocols for Assessing Mitophagy in Neuronal Cell Lines and Primary Neurons. Animal Models of Drug Addiction 2017, 123, 249 -277.
AMA StyleRuben K. Dagda, Monica Rice. Protocols for Assessing Mitophagy in Neuronal Cell Lines and Primary Neurons. Animal Models of Drug Addiction. 2017; 123 ():249-277.
Chicago/Turabian StyleRuben K. Dagda; Monica Rice. 2017. "Protocols for Assessing Mitophagy in Neuronal Cell Lines and Primary Neurons." Animal Models of Drug Addiction 123, no. : 249-277.
Mitochondria are major suppliers of cellular energy in neurons; however, utilization of energy from glycolysis vs. mitochondrial oxidative phosphorylation (OxPhos) in the presynaptic compartment during neurotransmission is largely unknown. Using presynaptic and postsynaptic recordings from the mouse calyx of Held, we examined the effect of acute selective pharmacological inhibition of glycolysis or mitochondrial OxPhos on multiple mechanisms regulating presynaptic function. Inhibition of glycolysis via glucose depletion and iodoacetic acid (1 mM) treatment, but not mitochondrial OxPhos, rapidly altered transmission, resulting in highly variable, oscillating responses. At reduced temperature, this same treatment attenuated synaptic transmission because of a smaller and broader presynaptic action potential (AP) waveform. We show via experimental manipulation and ion channel modeling that the altered AP waveform results in smaller Ca2+ influx, resulting in attenuated excitatory postsynaptic currents (EPSCs). In contrast, inhibition of mitochondria-derived ATP production via extracellular pyruvate depletion and bath-applied oligomycin (1 μM) had no significant effect on Ca2+ influx and did not alter the AP waveform within the same time frame (up to 30 min), and the resultant EPSC remained unaffected. Glycolysis, but not mitochondrial OxPhos, is thus required to maintain basal synaptic transmission at the presynaptic terminal. We propose that glycolytic enzymes are closely apposed to ATP-dependent ion pumps on the presynaptic membrane. Our results indicate a novel mechanism for the effect of hypoglycemia on neurotransmission. Attenuated transmission likely results from a single presynaptic mechanism at reduced temperature: a slower, smaller AP, before and independent of any effect on synaptic vesicle release or receptor activity.
Brendan Lujan; Christopher Kushmerick; Tania Das Banerjee; Ruben K. Dagda; Robert Renden. Glycolysis selectively shapes the presynaptic action potential waveform. Journal of Neurophysiology 2016, 116, 2523 -2540.
AMA StyleBrendan Lujan, Christopher Kushmerick, Tania Das Banerjee, Ruben K. Dagda, Robert Renden. Glycolysis selectively shapes the presynaptic action potential waveform. Journal of Neurophysiology. 2016; 116 (6):2523-2540.
Chicago/Turabian StyleBrendan Lujan; Christopher Kushmerick; Tania Das Banerjee; Ruben K. Dagda; Robert Renden. 2016. "Glycolysis selectively shapes the presynaptic action potential waveform." Journal of Neurophysiology 116, no. 6: 2523-2540.
Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson’s disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity. To test this hypothesis, hDJ-1 was overexpressed, purified and tested for activity towards 4-nitrophenyl acetate (pNPA) as µmol of pNPA hydrolyzed/min/mg·protein (U/mg protein). hDJ-1 showed maximum reaction velocity esterase activity (Vmax = 235.10 ± 12.00 U/mg protein), with a sigmoidal fit (S0.5 = 0.55 ± 0.040 mM) and apparent positive cooperativity (Hill coefficient of 2.05 ± 0.28). A PD-associated mutant of DJ-1 (M26I) lacked activity. Unlike its protease activity which is inactivated by reactive oxygen species (ROS), esterase activity of hDJ-1 is enhanced upon exposure to low concentrations of hydrogen peroxide (100 µM) suggesting that its activity is resistant to oxidative stress. Esterase activity of DJ-1 requires oxidation of catalytic cysteines, as chemically protecting cysteines blocked its activity whereas an oxido-mimetic mutant of DJ-1 (C106D) exhibited robust esterase activity. Molecular docking studies suggest that C106 and L126 within its catalytic site interact with esterase substrates. Overall, our data show that hDJ-1 contains intrinsic redox-sensitive esterase activity that is abolished in a PD-associated mutant form of the hDJ-1 protein.
Emmanuel Vázquez-Mayorga; Ángel G. Díaz-Sánchez; Ruben K. Dagda; Carlos A. Domínguez-Solís; Raul Y. Dagda; Cynthia K. Coronado-Ramírez; Alejandro Martínez-Martínez. Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson’s Disease. International Journal of Molecular Sciences 2016, 17, 1346 .
AMA StyleEmmanuel Vázquez-Mayorga, Ángel G. Díaz-Sánchez, Ruben K. Dagda, Carlos A. Domínguez-Solís, Raul Y. Dagda, Cynthia K. Coronado-Ramírez, Alejandro Martínez-Martínez. Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson’s Disease. International Journal of Molecular Sciences. 2016; 17 (8):1346.
Chicago/Turabian StyleEmmanuel Vázquez-Mayorga; Ángel G. Díaz-Sánchez; Ruben K. Dagda; Carlos A. Domínguez-Solís; Raul Y. Dagda; Cynthia K. Coronado-Ramírez; Alejandro Martínez-Martínez. 2016. "Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson’s Disease." International Journal of Molecular Sciences 17, no. 8: 1346.
The effects of temperature and the membrane-active protein CTII on the formation of nonbilayer structures in mitochondrial membranes were studied by 31P-NMR. An increase in ATP synthase activity was found for the first time to accompany the formation of nonbilayer packed phospholipids with immobilized molecular mobility in mitochondrial membranes. Computer modeling was additionally employed in studying the interaction of important phospholipids found in mitochondrial membranes with the molecular surface of CTII, which behaves like a dicyclohexylcarbodiimide-binding protein (DCCD-BP) of the F0 group in a lipid phase. Proton permeability toroidal pores were assumed to form in mitochondrial membranes from nonbilayer-packed phospholipids immobilized via interactions with DCCD-BP. Proton transport along a concentration gradient through the transit toroidal permeability pores may induce conformational changes necessary for mediating the catalytic activity of ATP synthase in the subunits of the F0–F1 complex.
S. E. Gasanov; A. A. Kim; R. K. Dagda. The possible role of nonbilayer structures in regulating ATP synthase activity in mitochondrial membranes. Biophysics 2016, 61, 596 -600.
AMA StyleS. E. Gasanov, A. A. Kim, R. K. Dagda. The possible role of nonbilayer structures in regulating ATP synthase activity in mitochondrial membranes. Biophysics. 2016; 61 (4):596-600.
Chicago/Turabian StyleS. E. Gasanov; A. A. Kim; R. K. Dagda. 2016. "The possible role of nonbilayer structures in regulating ATP synthase activity in mitochondrial membranes." Biophysics 61, no. 4: 596-600.
Arsenic exposure has been implicated as a risk factor for cardiovascular diseases, metabolic disorders, and cancer, yet the role mitochondrial dysfunction plays in the cellular mechanisms of pathology is largely unknown. To investigate arsenic-induced mitochondrial dysfunction in vascular smooth muscle cells (VSMCs), we exposed rat aortic smooth muscle cells (A7r5) to inorganic arsenic (iAs(III)) and its metabolite monomethylarsonous acid (MMA(III)) and compared their effects on mitochondrial function and oxidative stress. Our results indicate that MMA(III) is significantly more toxic to mitochondria than iAs(III). Exposure of VSMCs to MMA(III), but not iAs(III), significantly decreased basal and maximal oxygen consumption rates and concomitantly increased compensatory extracellular acidification rates, a proxy for glycolysis. Treatment with MMA(III) significantly increased hydrogen peroxide and superoxide levels compared to iAs(III). Exposure to MMA(III) resulted in significant decreases in mitochondrial ATP, aberrant perinuclear clustering of mitochondria, and decreased mitochondrial content. Mechanistically, we observed that mitochondrial superoxide and hydrogen peroxide contribute to mitochondrial toxicity, as treatment of cells with MnTBAP (a mitochondrial superoxide dismutase mimetic) and catalase significantly reduced mitochondrial respiration deficits and cell death induced by both arsenic compounds. Overall, our data demonstrates that MMA(III) is a mitochondria-specific toxicant that elevates mitochondrial and non-mitochondrial sources of ROS.
Clare Pace; Tania Das Banerjee; Barrett Welch; Roxana Khalili; Ruben K. Dagda; Jeff Angermann. Monomethylarsonous acid, but not inorganic arsenic, is a mitochondria-specific toxicant in vascular smooth muscle cells. Toxicology in Vitro 2016, 35, 188 -201.
AMA StyleClare Pace, Tania Das Banerjee, Barrett Welch, Roxana Khalili, Ruben K. Dagda, Jeff Angermann. Monomethylarsonous acid, but not inorganic arsenic, is a mitochondria-specific toxicant in vascular smooth muscle cells. Toxicology in Vitro. 2016; 35 ():188-201.
Chicago/Turabian StyleClare Pace; Tania Das Banerjee; Barrett Welch; Roxana Khalili; Ruben K. Dagda; Jeff Angermann. 2016. "Monomethylarsonous acid, but not inorganic arsenic, is a mitochondria-specific toxicant in vascular smooth muscle cells." Toxicology in Vitro 35, no. : 188-201.
Cobra venom cytotoxins are basic three-fingered, amphipathic, non-enzymatic proteins that constitute a major fraction of cobra venom. While cytotoxins cause mitochondrial dysfunction in different cell types, the mechanisms by which cytotoxins bind to mitochondria remain unknown. We analyzed the abilities of CTI and CTII, S-type and P-type cytotoxins from Naja naja oxiana respectively, to associate with isolated mitochondrial fractions or with model membranes that simulate the mitochondrial lipid environment by using a myriad of biophysical techniques. Phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy data suggest that both cytotoxins bind to isolated mitochondrial fractions and promote the formation of aberrant non-bilayer structures. We then hypothesized that CTI and CTII bind to cardiolipin (CL) to disrupt mitochondrial membranes. Collectively, 31P-NMR, electron paramagnetic resonance (EPR), proton NMR (1H-NMR), deuterium NMR (2H-NMR) spectroscopy, differential scanning calorimetry, and erythrosine phosphorescence assays suggest that CTI and CTII bind to CL to generate non-bilayer structures and promote the permeabilization, dehydration and fusion of large unilamellar phosphatidylcholine (PC) liposomes enriched with CL. On the other hand, CTII but not CTI caused biophysical alterations of large unilamellar PC liposomes enriched with phosphatidylserine (PS). Mechanistically, single molecule docking simulations identified putative CL, PS and PC binding sites in CTI and CTII. While the predicted binding sites for PS and PC share a high number of interactive amino acid residues in CTI and CTII, the CL biding sites in CTII and CTI are more divergent as it contains additional interactive amino acid residues. Overall, our data suggest that cytotoxins physically associate with mitochondrial membranes by binding to CL to disrupt mitochondrial structural integrity.
Sardar E. Gasanov; Indira H. Shrivastava; Firuz S. Israilov; Aleksandr A. Kim; Kamila A. Rylova; Boris Zhang; Ruben K. Dagda. Naja naja oxiana Cobra Venom Cytotoxins CTI and CTII Disrupt Mitochondrial Membrane Integrity: Implications for Basic Three-Fingered Cytotoxins. PLOS ONE 2015, 10, e0129248 .
AMA StyleSardar E. Gasanov, Indira H. Shrivastava, Firuz S. Israilov, Aleksandr A. Kim, Kamila A. Rylova, Boris Zhang, Ruben K. Dagda. Naja naja oxiana Cobra Venom Cytotoxins CTI and CTII Disrupt Mitochondrial Membrane Integrity: Implications for Basic Three-Fingered Cytotoxins. PLOS ONE. 2015; 10 (6):e0129248.
Chicago/Turabian StyleSardar E. Gasanov; Indira H. Shrivastava; Firuz S. Israilov; Aleksandr A. Kim; Kamila A. Rylova; Boris Zhang; Ruben K. Dagda. 2015. "Naja naja oxiana Cobra Venom Cytotoxins CTI and CTII Disrupt Mitochondrial Membrane Integrity: Implications for Basic Three-Fingered Cytotoxins." PLOS ONE 10, no. 6: e0129248.