Jeffery D Molkentin

University of Cincinnati, Cincinnati, Ohio, United States

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Publications (442)3875.69 Total impact

  • [Show abstract] [Hide abstract] ABSTRACT: The heart either hypertrophies or dilates in response to familial mutations in genes encoding sarcomeric proteins, which are responsible for contraction and pumping. These mutations typically alter calcium-dependent tension generation within the sarcomeres, but how this translates into the spectrum of hypertrophic versus dilated cardiomyopathy is unknown. By generating a series of cardiac-specific mouse models that permit the systematic tuning of sarcomeric tension generation and calcium fluxing, we identify a significant relationship between the magnitude of tension developed over time and heart growth. When formulated into a computational model, the integral of myofilament tension development predicts hypertrophic and dilated cardiomyopathies in mice associated with essentially any sarcomeric gene mutations, but also accurately predicts human cardiac phenotypes from data generated in induced-pluripotent-stem-cell-derived myocytes from familial cardiomyopathy patients. This tension-based model also has the potential to inform pharmacologic treatment options in cardiomyopathy patients.
    No preview · Article · Apr 2016 · Cell
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    [Show abstract] [Hide abstract] ABSTRACT: Duchenne muscular dystrophy is an X-linked recessive disease caused by mutations in the gene encoding dystrophin. Loss of dystrophin protein compromises the stability of the sarcolemma membrane surrounding each muscle cell fiber, leading to membrane ruptures and leakiness that induces myofiber necrosis, a subsequent inflammatory response and progressive tissue fibrosis with loss of functional capacity. Cathepsin S (Ctss) is a cysteine protease that is actively secreted in areas of tissue injury and ongoing inflammation, where it participates in extracellular matrix remodeling and healing. Here, we show significant induction of Ctss expression and proteolytic activity following acute muscle injury or in muscle from mdx mice, a model of Duchenne muscular dystrophy. To examine the functional ramifications associated with greater Ctss expression, the Ctss gene was deleted in the mdx genetic background, resulting in protection from muscular dystrophy pathogenesis that included reduced myofiber turnover and histopathology, reduced fibrosis and improved running capacity. Mechanistically, deletion of the Ctss gene in the mdx background significantly increased myofiber sarcolemmal membrane stability with greater expression and membrane localization of utrophin, integrins and β-dystroglycan, which anchor the membrane to the basal lamina and underlying contractile proteins. Consistent with these results, skeletal muscle-specific transgenic mice over-expressing Ctss showed increased myofiber necrosis, muscle histopathology and a functional deficit reminiscent of muscular dystrophy. Hence, Ctss induction during muscular dystrophy is a pathologic event that partially underlies disease pathogenesis, and its inhibition might serve as a new therapeutic strategy in DMD.
    Preview · Article · Mar 2016 · Journal of Biological Chemistry
  • [Show abstract] [Hide abstract] ABSTRACT: Muscular dystrophy (MD) is associated with mutations in genes that stabilize the myofiber plasma membrane, such as through the dystrophin-glycoprotein complex. Instability of this complex or defects in membrane repair/integrity leads to calcium influx and myofiber necrosis leading to progressive dystrophic disease. MD pathogenesis is also associated with increased skeletal muscle protease levels and activity that could augment weakening of the sarcolemma through greater degradation of cellular attachment complexes. Here we observed a compensatory increase in the serine protease inhibitor Serpina3n in mouse models of MD and after acute muscle tissue injury. Serpina3n muscle-specific transgenic mice were generated to model this increase in expression, which reduced the activity of select proteases in dystrophic skeletal muscle and protected muscle from both acute injury with cardiotoxin and from chronic muscle disease in the mdx or Sgcd(-/-) MD genetic backgrounds. The Serpina3n transgene mitigated muscle degeneration and fibrosis, reduced creatine kinase serum levels, restored running capacity on a treadmill, and reduced membrane leakiness in vivo that is characteristic of mdx and Sgcd(-/-) mice. Mechanistically, we show that increased Serpina3n promotes increased sarcolemma membrane integrity and stability in dystrophic mouse models in association with greater membrane residence of the integrins, the dystrophin/utrophin-glycoprotein complex of proteins, and annexin A1. Hence, Serpina3n blocks endogenous increases in the activity of select skeletal muscle resident proteases during injury or dystrophic disease, which stabilizes the sarcolemma leading to less myofiber degeneration and increased regeneration. These results suggest the use of select protease inhibitors as a strategy for treating MD.
    No preview · Article · Jan 2016 · Human Molecular Genetics
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    Jop H. van Berlo · Jeffery D. Molkentin
    Preview · Article · Jan 2016 · Circulation Research
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    [Show abstract] [Hide abstract] ABSTRACT: Persistent elevation of Ca(2+) influx due to prolongation of the action potential (AP), chronic activation of the β-adrenergic system and molecular remodeling occurs in stressed and diseased hearts. Increases in Ca(2+) influx are usually linked to prolonged myocyte action potentials and arrhythmias. However, the contribution of chronic enhancement of Cav1.2 activity on cardiac electrical remodeling and arrhythmogenicity has not been completely defined and is the subject of this study. Chronically increased Cav1.2 activity was produced with a cardiac specific, inducible double transgenic (DTG) mouse system overexpressing the β2a subunit of Cav (Cavβ2a). DTG myocytes had increased L-type Ca(2+) current (ICa-L), myocyte shortening, and Ca(2+) transients. DTG mice had enhanced cardiac performance, but died suddenly and prematurely. Telemetric electrocardiograms revealed shortened QT intervals in DTG mice. The action potential duration (APD) was shortened in DTG myocytes due to significant increases of potassium currents and channel abundance. However, shortened AP in DTG myocytes did not fully limit excess Ca(2+) influx and increased the peak and tail ICa-L. Enhanced ICa promoted sarcoplasmic reticulum (SR) Ca(2+) overload, diastolic Ca(2+) sparks and waves, and increased NCX activity, causing increased occurrence of early and delayed afterdepolarizations (EADs and DADs) that may contribute to premature ventricular beats and ventricular tachycardia. AV blocks that could be related to fibrosis of the AV node were also observed. Our study suggests that increasing ICa-L does not necessarily result in AP prolongation but causes SR Ca(2+) overload and fibrosis of AV node and myocardium to induce cellular arrhythmogenicity, arrhythmias, and conduction abnormalities.
    Full-text · Article · Jan 2016 · Archiv für Kreislaufforschung
  • Xiyuan Lu · Jennifer Kwong · Jeffery D Molkentin · Donald M Bers
    [Show abstract] [Hide abstract] ABSTRACT: Rationale: Mitochondria produce ATP, especially critical for survival of highly aerobic cells such as cardiac myocytes. Conversely, opening of mitochondrial high-conductance and long-lasting permeability transition pores (mPTP) causes respiratory uncoupling, mitochondrial injury and cell death. However, low-conductance and transient mPTP openings (tPTP) might limit mitochondrial Ca(2+) load and be cardioprotective, but direct evidence for tPTP in cells is limited. Objective: To directly characterize tPTP occurrence during SR Ca(2+) release in adult cardiac myocytes. Methods and results: Here, we measured tPTP directly as transient drops in mitochondrial [Ca(2+)] ([Ca(2+)]mito) and membrane potential (ΔΨm) in adult cardiac myocytes during cyclical sarcoplasmic reticulum Ca release, by simultaneous live imaging of 500-1,000 individual mitochondria. The frequency of tPTPs rose at higher [Ca(2+)]mito, [Ca(2+)]i, with 1 µM peroxide exposure and in myocyte from failing hearts. The tPTPs were suppressed by preventing mitochondrial Ca(2+) influx, by mPTP inhibitor cyclosporine A, sanglifehrin and in cyclophilin D knockout mice. These tPTP events were 57 ± 5 s in duration, but were rare (occurring in <0.1% of myocyte mitochondria at any moment) such that the overall energetic cost to the cell is minimal. The tPTP pore size is much smaller than for permanent mPTP, as neither Rhod-2 nor calcien (600 Da) were lost. Thus, proteins and even molecules the size of NADH (663 Da) will be retained during these tPTP. Conclusions: We conclude that tPTP openings (MitoWinks) may be molecularly related to pathological mPTP, but are likely to be normal physiological manifestation that benefits mitochondrial (and cell) survival by allowing individual mitochondria to reset themselves with little overall energetic cost.
    No preview · Article · Dec 2015 · Circulation Research
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    [Show abstract] [Hide abstract] ABSTRACT: The differentiation of fibroblasts into myofibroblasts mediates tissue wound healing and fibrotic remodelling, although the molecular programme underlying this process remains poorly understood. Here we perform a genome-wide screen for genes that control myofibroblast transformation, and identify the RNA-binding protein muscleblind-like1 (MBNL1). MBNL1 overexpression promotes transformation of fibroblasts into myofibroblasts, whereas loss of Mbnl1 abrogates transformation and impairs the fibrotic phase of wound healing in mouse models of myocardial infarction and dermal injury. Mechanistically, MBNL1 directly binds to and regulates a network of differentiation-specific and cytoskeletal/matrix-assembly transcripts to promote myofibroblast differentiation. One of these transcripts is the nodal transcriptional regulator serum response factor (SRF), whereas another is calcineurin Aβ. CRISPR-Cas9-mediated gene-editing of the MBNL1-binding site within the Srf 3'UTR impairs myofibroblast differentiation, whereas in vivo deletion of Srf in fibroblasts impairs wound healing and fibrosis. These data establish a new RNA-dependent paradigm for myofibroblast formation through MBNL1.
    Preview · Article · Dec 2015 · Nature Communications
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    Lei Li · Yi Chen · Jing Li · Haifeng Yin · Xiaoyun Guo · Jessica Doan · Jeffery D Molkentin · Qinghang Liu
    [Show abstract] [Hide abstract] ABSTRACT: TAK1 (TGFβ-activated kinase-1) signaling is essential in regulating a number of important biological functions, including innate immunity, inflammatory response, cell growth and differentiation, and myocardial homeostasis. The precise role of TAK1 in the adult heart under pathological conditions remains largely unknown. Importantly, we observed that TAK1 is upregulated during compensatory hypertrophy but downregulated in end-stage heart failure. Here we generated transgenic mice with inducible expression of an active TAK1 mutant (TAK1ΔN) in the adult heart. TAK1ΔN transgenic mice developed greater cardiac hypertrophy compared with control mice after transverse aortic constriction (TAC), which was largely blocked by ablation of calcineurin Aβ. Expression of TAK1ΔN also promoted NFAT (nuclear factor of activated T-cells) transcriptional activity in luciferase reporter mice at baseline, which was further enhanced after TAC. Our results revealed that activation of TAK1 promoted adaptive cardiac hypertrophy through a cross-talk between calcineurin-NFAT and IKK-NFκB pathways. More significantly, adult-onset inducible expression of TAK1ΔN protected the myocardium from adverse remodeling and heart failure after myocardial infarction or long-term pressure overload, by preventing cardiac cell death and fibrosis. Mechanistically, TAK1 exerts its cardioprotective effect through activation of NFAT/NFκB, downregulation of Bnip3, and inhibition of cardiac cell death.
    Preview · Article · Nov 2015 · Scientific Reports
  • [Show abstract] [Hide abstract] ABSTRACT: Objective: Periostin is a secreted protein that can alter extracellular matrix remodeling in response to tissue injury. However, the functional role of periostin in the development of atherosclerotic plaques has yet to be described despite its observed induction in diseased vessels and presence in the serum. Approach and results: Hyperlipidemic, apolipoprotein E-null mice (ApoE(-/) (-)) were crossed with periostin (Postn(-/-)) gene-deleted mice and placed on a high-fat diet for 6 or 14 weeks to induce atherosclerosis. En face analysis of aortas showed significantly decreased lesion areas of ApoE(-/-) Postn(-/-) mice compared with ApoE(-/-) mice, as well as a reduced inflammatory response with less macrophage content. Moreover, diseased aortas from ApoE(-/-) Postn(-/-) mice displayed a disorganized extracellular matrix with less collagen cross linking and smaller fibrotic caps, as well as increased matrix metalloproteinase-2, metalloproteinase-13, and procollagen-lysine, 2-oxoglutarate 5-dioxygenase-1 mRNA expression. Furthermore, the loss of periostin was associated with a switch in vascular smooth muscle cells toward a more proliferative and synthetic phenotype. Mechanistically, the loss of periostin reduced macrophage recruitment by transforming growth factor-β in cellular migration assays. Conclusions: These are the first genetic data detailing the function of periostin as a regulator of atherosclerotic lesion formation and progression. The data suggest that periostin could be a therapeutic target for atherosclerotic plaque formation through modulation of the immune response and extracellular matrix remodeling.
    No preview · Article · Nov 2015 · Arteriosclerosis Thrombosis and Vascular Biology
  • [Show abstract] [Hide abstract] ABSTRACT: Thrombospondins are a family of stress-inducible secreted glycoproteins that underlie tissue remodeling. We recently reported that thrombospondin-4 (Thbs4) has a critical intracellular function where it regulates the adaptive endoplasmic reticulum (ER) stress pathway through activating transcription factor 6α (Atf6α). Here, we dissect the domains of Thbs4 that mediate interactions with ER proteins such as BiP (Grp78) and Atf6α, and the domains mediating activation of the ER stress response. Functionally, Thbs4 localized to the ER and post-ER vesicles and was actively secreted in cardiomyocytes, as were the T3R and TSP-C domains, while the LamG domain localized to the Golgi apparatus. We also mutated the major calcium-binding motifs within the T3R domain of full-length Thbs4, causing ER retention and secretion blockade. The T3R and TSP-C domains as well as wildtype Thbs4 and the calcium-binding mutant, interacted with Atf6α, induced an adaptive ER stress response, and caused expansion of intracellular vesicles. In contrast, overexpression of a related secreted oligomeric glycoprotein, Nell2, which lacks only the T3R and TSP-C domains, did not cause these effects. Finally, deletion of Atf6α abrogated Thbs4-induced vesicular expansion. Taken together, these data identify the critical intracellular functional domains of Thbs4, which was formerly thought to only have extracellular functions.
    No preview · Article · Oct 2015 · Molecular and Cellular Biology
  • [Show abstract] [Hide abstract] ABSTRACT: There are 3 protein phosphatase 1 (PP1) catalytic isoforms (α, β and γ) encoded within the mammalian genome. These 3 gene products share ~90% amino acid homology within their catalytic domains but each has unique N- and C-termini that likely underlie distinctive subcellular localization or functionality. In this study, we assessed the effect associated with loss of each PP1 isoform in the heart using a conditional Cre-loxP targeting approach in mice. Ppp1ca-loxP, Ppp1cb-loxP and Ppp1cc-oxP alleles were crossed with either an Nkx2.5-Cre knock-in containing allele for early embryonic deletion or a tamoxifen inducible α-myosin heavy chain (αMHC)-MerCreMer transgene for adult and cardiac-specific deletion. We determined that while deletion of Ppp1ca (PP1α) or Ppp1cc (PP1γ) had little effect on the whole heart, deletion of Ppp1cb (PP1β) resulted in concentric remodeling of the heart, interstitial fibrosis and contractile dysregulation, using either the embryonic or adult-specific Cre-expressing alleles. However, myocytes isolated from Ppp1cb deleted hearts surprisingly showed enhanced contractility. Mechanistically we found that deletion of any of the 3 PP1 gene-encoding isoforms had no effect on phosphorylation of phospholamban, nor were Ca(2+) handling dynamics altered in adult myocytes from Ppp1cb deleted hearts. However, loss of Ppp1cb from the heart, but not Ppp1ca or Ppp1cc, resulted in elevated phosphorylation of myofilament proteins such as myosin light chain 2 and cardiac myosin binding protein C, consistent with an enriched localization profile of this isoform to the sarcomeres. These results suggest a unique functional role for the PP1β isoform in affecting cardiac contractile function.
    No preview · Article · Sep 2015 · Journal of Molecular and Cellular Cardiology
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    [Show abstract] [Hide abstract] ABSTRACT: Canonical protein phosphatase 3/calcineurin signaling is central to numerous physiological processes. Here we provide evidence that calcineurin plays a pivotal role in controlling systemic energy and body weight homeostasis. Knockdown of calcineurin in Drosophila melanogaster led to a decrease in body weight and energy stores, and increased energy expenditure. In mice, global deficiency of catalytic subunit Ppp3cb, and tissue-specific ablation of regulatory subunit Ppp3r1 from skeletal muscle, but not adipose tissue or liver, led to protection from high-fat-diet-induced obesity and comorbid sequelæ. Ser637 hyperphosphorylation of dynamin-related protein 1 (Drp1) in skeletal muscle of calcineurin-deficient mice was associated with mitochondrial elongation into power-cable-shaped filaments and increased mitochondrial respiration, but also with attenuated exercise performance. Our data suggest that calcineurin acts as highly conserved pivot for the adaptive metabolic responses to environmental changes such as high-fat, high-sugar diets or exercise.
    Full-text · Article · Sep 2015 · Cell metabolism
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    [Show abstract] [Hide abstract] ABSTRACT: Abstract—We have previously shown,that the calcium-calmodulin‐regulated phosphatase calcineurin (PP2B) is sufficient to induce cardiac hypertrophy that transitions to heart failure in transgenic mice. Given the rapid onset of heart failure in these mice, we hypothesized that calcineurin signaling would stimulate myocardial cell apoptosis. However, utilizing multiple approaches, we determined that calcineurin-mediated hypertrophy protected cardiac myocytes from apoptosis, suggesting a model,of heart failure that is independent,of apoptosis. Adenovirally mediated,gene,transfer of a
    Full-text · Article · Aug 2015
  • [Show abstract] [Hide abstract] ABSTRACT: Stromal interaction molecule 1 (STIM1) is a Ca(2+) sensor that partners with Orai1 to elicit Ca(2+) entry in response to endoplasmic reticulum (ER) Ca(2+) store depletion. While store-operated Ca(2+) entry (SOCE) is important for maintaining ER Ca(2+) homeostasis in non-excitable cells, it is unclear what role it plays in the heart, although STIM1 is expressed in the heart and upregulated during disease. Here we analyzed transgenic mice with STIM1 overexpression in the heart to model the known increase of this protein in response to disease. As expected, STIM1 transgenic myocytes showed enhanced Ca(2+) entry following store depletion and partial co-localization with the type 2 ryanodine receptor (RyR2) within the sarcoplasmic reticulum (SR), as well as enrichment around the sarcolemma. STIM1 transgenic mice exhibited sudden cardiac death as early as 6weeks of age, while mice surviving past 12weeks of age developed heart failure with hypertrophy, induction of the fetal gene program, histopathology and mitochondrial structural alterations, loss of ventricular functional performance and pulmonary edema. Younger, pre-symptomatic STIM1 transgenic mice exhibited enhanced pathology following pressure overload stimulation or neurohumoral agonist infusion, compared to controls. Mechanistically, cardiac myocytes isolated from STIM1 transgenic mice displayed spontaneous Ca(2+) transients that were prevented by the SOCE blocker SKF-96365, increased L-type Ca(2+) channel (LTCC) current, and enhanced Ca(2+) spark frequency. Moreover, adult cardiac myocytes from STIM1 transgenic mice showed both increased diastolic Ca(2+) and maximal transient amplitude but no increase in total SR Ca(2+) load. Associated with this enhanced Ca(2+) profile was an increase in cardiac nuclear factor of activated T-cells (NFAT) and Ca(2+)/calmodulin-dependent kinase II (CaMKII) activity. We conclude that STIM1 has an unexpected function in the heart where it alters communication between the sarcolemma and SR resulting in greater Ca(2+) flux and a leaky SR compartment. Copyright © 2015. Published by Elsevier Ltd.
    No preview · Article · Aug 2015 · Journal of Molecular and Cellular Cardiology
  • [Show abstract] [Hide abstract] ABSTRACT: In the heart, augmented Ca(2+) fluxing drives contractility and ATP generation through mitochondrial Ca(2+) loading. Pathologic mitochondrial Ca(2+) overload with ischemic injury triggers mitochondrial permeability transition pore (MPTP) opening and cardiomyocyte death. Mitochondrial Ca(2+) uptake is primarily mediated by the mitochondrial Ca(2+) uniporter (MCU). Here, we generated mice with adult and cardiomyocyte-specific deletion of Mcu, which produced mitochondria refractory to acute Ca(2+) uptake, with impaired ATP production, and inhibited MPTP opening upon acute Ca(2+) challenge. Mice lacking Mcu in the adult heart were also protected from acute ischemia-reperfusion injury. However, resting/basal mitochondrial Ca(2+) levels were normal in hearts of Mcu-deleted mice, and mitochondria lacking MCU eventually loaded with Ca(2+) after stress stimulation. Indeed, Mcu-deleted mice were unable to immediately sprint on a treadmill unless warmed up for 30 min. Hence, MCU is a dedicated regulator of short-term mitochondrial Ca(2+) loading underlying a "fight-or-flight" response that acutely matches cardiac workload with ATP production. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Jun 2015 · Cell Reports
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    A R Burr · J D Molkentin
    [Show abstract] [Hide abstract] ABSTRACT: Muscular dystrophy (MD) refers to a clinically and genetically heterogeneous group of degenerative muscle disorders characterized by progressive muscle wasting and often premature death. Although the primary defect underlying most forms of MD typically results from a loss of sarcolemmal integrity, the secondary molecular mechanisms leading to muscle degeneration and myofiber necrosis is debated. One hypothesis suggests that elevated or dysregulated cytosolic calcium is the common transducing event, resulting in myofiber necrosis in MD. Previous measurements of resting calcium levels in myofibers from dystrophic animal models or humans produced equivocal results. However, recent studies in genetically altered mouse models have largely solidified the calcium hypothesis of MD, such that models with artificially elevated calcium in skeletal muscle manifest fulminant dystrophic-like disease, whereas models with enhanced calcium clearance or inhibited calcium influx are resistant to myofiber death and MD. Here, we will review the field and the recent cadre of data from genetically altered mouse models, which we propose have collectively mostly proven the hypothesis that calcium is the primary effector of myofiber necrosis in MD. This new consensus on calcium should guide future selection of drugs to be evaluated in clinical trials as well as gene therapy-based approaches.Cell Death and Differentiation advance online publication, 19 June 2015; doi:10.1038/cdd.2015.65.
    Preview · Article · Jun 2015 · Cell death and differentiation
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    [Show abstract] [Hide abstract] ABSTRACT: Acute pancreatitis is caused by toxins that induce acinar cell calcium overload, zymogen activation, cytokine release and cell death, yet is without specific drug therapy. Mitochondrial dysfunction has been implicated but the mechanism not established. We investigated the mechanism of induction and consequences of the mitochondrial permeability transition pore (MPTP) in the pancreas using cell biological methods including confocal microscopy, patch clamp technology and multiple clinically representative disease models. Effects of genetic and pharmacological inhibition of the MPTP were examined in isolated murine and human pancreatic acinar cells, and in hyperstimulation, bile acid, alcoholic and choline-deficient, ethionine-supplemented acute pancreatitis. MPTP opening was mediated by toxin-induced inositol trisphosphate and ryanodine receptor calcium channel release, and resulted in diminished ATP production, leading to impaired calcium clearance, defective autophagy, zymogen activation, cytokine production, phosphoglycerate mutase 5 activation and necrosis, which was prevented by intracellular ATP supplementation. When MPTP opening was inhibited genetically or pharmacologically, all biochemical, immunological and histopathological responses of acute pancreatitis in all four models were reduced or abolished. This work demonstrates the mechanism and consequences of MPTP opening to be fundamental to multiple forms of acute pancreatitis and validates the MPTP as a drug target for this disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    Full-text · Article · Jun 2015 · Gut
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    [Show abstract] [Hide abstract] ABSTRACT: During apoptosis the pro-death Bcl-2 family members Bax and Bak induce mitochondrial outer membrane permeabilization (MOMP) to mediate cell death. Recently, it was shown that Bax and Bak are also required for mitochondrial permeability transition pore (MPTP)-dependent necrosis, where, in their non-oligomeric state, they enhance permeability characteristics of the outer mitochondrial membrane. Necroptosis is another form of regulated necrosis involving the death receptors and receptor interacting protein kinases (RIP proteins, by Ripk genes). Here, we show cells or mice deficient for Bax/Bak or cyclophilin D, a protein that regulates MPTP opening, are resistant to cell death induced by necroptotic mediators. We show that Bax/Bak oligomerization is required for necroptotic cell death and that this oligomerization reinforces MPTP opening. Mechanistically, we observe mixed lineage kinase domain-like (MLKL) protein and cofilin-1 translocation to the mitochondria following necroptosis induction, while expression of the mitochondrial matrix isoform of the antiapoptotic Bcl-2 family member, myeloid cell leukemia 1 (Mcl-1), is significantly reduced. Some of these effects are lost with necroptosis inhibition in Bax/Bak1 double null, Ppif-/-, or Ripk3-/- fibroblasts. Hence, downstream mechanisms of cell death induced by necroptotic stimuli utilize both Bax/Bak to generate apoptotic pores in the outer mitochondrial membrane as well as MPTP opening in association with known mitochondrial death modifying proteins.
    Full-text · Article · Jun 2015 · PLoS ONE
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    [Show abstract] [Hide abstract] ABSTRACT: The mitochondrial peptidyl prolyl isomerase cyclophilin D (CypD) activates permeability transition (PT). To study the role of CypD in this process we compared the functions of brain mitochondria isolated from wild type (BMWT) and CypD knockout (Ppif(-/-)) mice (BMKO) with and without CypD inhibitor Cyclosporin A (CsA) under normal and Ca(2+) stress conditions. Our data demonstrate that BMKO are characterized by higher rates of glutamate/malate-dependent oxidative phosphorylation, higher membrane potential and higher resistance to detrimental Ca(2+) effects than BMWT. Under the elevated Ca(2+) and correspondingly decreased membrane potential the dose response in BMKO shifts to higher Ca(2+) concentrations as compared to BMWT. However, significantly high Ca(2+) levels result in complete loss of membrane potential in BMKO, too. CsA diminishes the loss of membrane potential in BMWT but has no protecting effect in BMKO. The results are in line with the assumption that PT is regulated by CypD under the control of matrix Ca(2+). Due to missing of CypD the BMKO can favor PT only at high Ca(2+) concentrations. It is concluded that CypD sensitizes the brain mitochondria to PT, and its inhibition by CsA or CypD absence improves the complex I-related mitochondrial function and increases mitochondria stability against Ca(2+) stress. Copyright © 2015. Published by Elsevier Inc.
    Full-text · Article · May 2015 · Archives of Biochemistry and Biophysics
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    Jason Karch · Jeffery D Molkentin
    [Show abstract] [Hide abstract] ABSTRACT: Although the molecular effectors of apoptotic cell death have been largely annotated over the past 30 years, leading to a strong biological understanding of this process and its importance in cell biology, cell death through necrosis has only recently been accepted as a similarly regulated process with definable molecular effectors. The mitochondria are important and central mediators of both apoptosis and regulated necrosis. In apoptosis, the B-cell leukemia/lymphoma 2 (Bcl-2) family members Bcl-2-associated protein x (Bax) and Bcl-2 homologues antagonist/killer (Bak) undergo oligomerization in the outer mitochondrial membrane resulting in the release of apoptosis inducing substrates and the activation of caspases and nucleases. In contrast, during necrosis the mitochondria become dysfunctional and maladaptive in conjunction with reactive oxygen species production and the loss of ATP production, in part through opening of the mitochondrial permeability transition pore. Although regulated necrosis is caspase-independent, recent evidence has shown that it still requires the apoptotic regulators Bax/Bak, which can regulate the permeability characteristics of the outer mitochondrial membrane in their nonoligomerized state. Here, we review the nonapoptotic side of Bcl-2 family, specifically the role of Bax/Bak in regulated necrotic cell death. We will also discuss how these Bcl-2 family member effectors could be part of a larger integrated network that ultimately decides the fate of a given cell somewhere within a molecular continuum between apoptosis and regulated necrosis. © 2015 American Heart Association, Inc.
    Full-text · Article · May 2015 · Circulation Research

Publication Stats

32k Citations
3,875.69 Total Impact Points


  • 1998-2015
    • University of Cincinnati
      • Department of Pediatrics
      Cincinnati, Ohio, United States
  • 2009-2012
    • Howard Hughes Medical Institute
      Ashburn, Virginia, United States
    • Hannover Medical School
      • Department of Cardiology and Angiology
      Hanover, Lower Saxony, Germany
    • Washington University in St. Louis
      • Center for Pharmacogenomics
      Saint Louis, MO, United States
    • University of Maryland, Baltimore
      • Department of Physiology
      Baltimore, Maryland, United States
  • 2007-2012
    • University of Washington Seattle
      • Department of Physiology and Biophysics
      Seattle, WA, United States
    • The Rockefeller University
      New York, New York, United States
    • University of Oslo
      Kristiania (historical), Oslo, Norway
    • University of Cologne
      Köln, North Rhine-Westphalia, Germany
    • The Scripps Research Institute
      لا هویا, California, United States
    • Indiana University-Purdue University Indianapolis
      Indianapolis, Indiana, United States
    • Albany Medical College
      • Center for Immunology and Microbial Disease
      Albany, New York, United States
  • 2011
    • Shanghai Jiao Tong University
      • School of Agriculture and Biology
      Shanghai, Shanghai Shi, China
  • 2000-2011
    • Cincinnati Children's Hospital Medical Center
      • • Division of Molecular Cardiovascular Biology
      • • Department of Pediatrics
      Cincinnati, Ohio, United States
  • 2001-2007
    • Boston University
      • Department of Biology
      Boston, Massachusetts, United States
  • 1994-2007
    • Medical College of Wisconsin
      • • Department of Cell Biology, Neurobiology & Anatomy
      • • Department of Physiology
      Milwaukee, Wisconsin, United States
  • 2006
    • University of Helsinki
      • Department of Physical Sciences
      Helsinki, Uusimaa, Finland
    • University of Pittsburgh
      Pittsburgh, Pennsylvania, United States
  • 2002-2006
    • University of Toronto
      • Department of Laboratory Medicine and Pathobiology
      Toronto, Ontario, Canada
  • 2000-2006
    • Harvard University
      Cambridge, Massachusetts, United States
  • 2005
    • Procter & Gamble
      Cincinnati, Ohio, United States
  • 2004
    • University of Freiburg
      Freiburg, Baden-Württemberg, Germany
    • University of Missouri
      • Department of Biochemistry
      Columbia, Missouri, United States
  • 2003-2004
    • Maastricht University
      • Department of Cardiology
      Maestricht, Limburg, Netherlands
  • 1996-1999
    • University of Texas at Dallas
      • Molecular Biology
      Richardson, Texas, United States
    • The American Society for Biochemistry and Molecular Biology
      Порт-Артур, Texas, United States
  • 1996-1998
    • University of Texas Southwestern Medical Center
      • Department of Molecular Biology
      Dallas, Texas, United States