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Cohen DJ, Dennis CD, Deng J, Boyan BD, Schwartz Z. Estradiol induces bone osteolysis in triple-negative breast cancer via its membrane-associated receptor ERα36. JBMR Plus 2024; 8:ziae041. [PMID: 38644978 PMCID: PMC11032217 DOI: 10.1093/jbmrpl/ziae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/31/2024] [Accepted: 02/27/2024] [Indexed: 04/23/2024] Open
Abstract
Triple-negative breast cancer (TNBC) is thought to be an estradiol-independent, hormone therapy-resistant cancer because of lack of estrogen receptor alpha 66 (ERα66). We identified a membrane-bound splice variant, ERα36, in TNBC cells that responds to estrogen (E2) and may contribute to bone osteolysis. We demonstrated that the MDA-MB-231 TNBC cell line, which expresses ERα36 similarly to MCF7 cells, is responsive to E2, forming osteolytic tumors in vivo. MDA-MB-231 cells activate osteoclasts in a paracrine manner. Conditioned media (CM) from MDA-MB-231 cells treated with bovine serum albumin-bound E2 (E2-BSA) increased activation of human osteoclast precursor cells; this was blocked by addition of anti-ERα36 antibody to the MDA-MB-231 cultures. Osteoclast activation and bone resorption genes were elevated in RAW 264.7 murine macrophages following treatment with E2-BSA-stimulated MDA-MB-231 CM. E2 and E2-BSA increased phospholipase C (PLC) and protein kinase C (PKC) activity in MDA-MB-231 cells. To examine the role of ERα36 signaling in bone osteolysis in TNBC, we used our bone-cancer interface mouse model in female athymic homozygous Foxn1nu mice. Mice with MDA-MB-231 tumors and treated with tamoxifen (TAM), E2, or TAM/E2 exhibited increased osteolysis, cortical bone breakdown, pathologic fracture, and tumor volume; the combined E2/TAM group also had reduced bone volume. These results suggest that E2 increased osteolytic lesions in TNBC through a membrane-mediated PLC/PKC pathway involving ERα36, which was enhanced by TAM, demonstrating the role of ERα36 and its membrane-associated signaling pathway in bone tumors. This work suggests that ERα36 may be a potential therapeutic target in patients with TNBC.
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Affiliation(s)
- D Joshua Cohen
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Cydney D Dennis
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Jingyao Deng
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
| | - Barbara D Boyan
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Zvi Schwartz
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, United States
- Department of Periodontics, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229United States
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Brunetti V, Soda T, Berra-Romani R, De Sarro G, Guerra G, Scarpellino G, Moccia F. Two Signaling Modes Are Better than One: Flux-Independent Signaling by Ionotropic Glutamate Receptors Is Coming of Age. Biomedicines 2024; 12:880. [PMID: 38672234 PMCID: PMC11048239 DOI: 10.3390/biomedicines12040880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/02/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the central nervous system. Glutamatergic transmission can be mediated by ionotropic glutamate receptors (iGluRs), which mediate rapid synaptic depolarization that can be associated with Ca2+ entry and activity-dependent change in the strength of synaptic transmission, as well as by metabotropic glutamate receptors (mGluRs), which mediate slower postsynaptic responses through the recruitment of second messenger systems. A wealth of evidence reported over the last three decades has shown that this dogmatic subdivision between iGluRs and mGluRs may not reflect the actual physiological signaling mode of the iGluRs, i.e., α-amino-3-hydroxy-5-methyl-4-isoxasolepropionic acid (AMPA) receptors (AMPAR), kainate receptors (KARs), and N-methyl-D-aspartate (NMDA) receptors (NMDARs). Herein, we review the evidence available supporting the notion that the canonical iGluRs can recruit flux-independent signaling pathways not only in neurons, but also in brain astrocytes and cerebrovascular endothelial cells. Understanding the signaling versatility of iGluRs can exert a profound impact on our understanding of glutamatergic synapses. Furthermore, it may shed light on novel neuroprotective strategies against brain disorders.
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Affiliation(s)
- Valentina Brunetti
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, 27110 Pavia, Italy; (V.B.); (G.S.)
| | - Teresa Soda
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (T.S.); (G.D.S.)
| | - Roberto Berra-Romani
- Department of Biomedicine, School of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico;
| | - Giovambattista De Sarro
- Department of Health Sciences, School of Medicine and Surgery, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy; (T.S.); (G.D.S.)
- System and Applied Pharmacology@University Magna Grecia, Science of Health Department, School of Medicine, Magna Graecia University of Catanzaro, 88110 Catanzaro, Italy
| | - Germano Guerra
- Department of Medicine and Health Science “Vincenzo Tiberio”, School of Medicine and Surgery, University of Molise, 86100 Campobasso, Italy;
| | - Giorgia Scarpellino
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, 27110 Pavia, Italy; (V.B.); (G.S.)
| | - Francesco Moccia
- Department of Medicine and Health Science “Vincenzo Tiberio”, School of Medicine and Surgery, University of Molise, 86100 Campobasso, Italy;
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3
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Narasaki S, Noguchi S, Urabe T, Harada K, Hide I, Tanaka S, Yanase Y, Kajimoto T, Uchida K, Tsutsumi YM, Sakai N. Identification of protein kinase C domains involved in its translocation induced by propofol. Eur J Pharmacol 2023; 955:175806. [PMID: 37230321 DOI: 10.1016/j.ejphar.2023.175806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/21/2023] [Accepted: 05/22/2023] [Indexed: 05/27/2023]
Abstract
Propofol is widely used for general anesthesia and sedation; however, the mechanisms of its anesthetic and adverse effects are not fully understood. We have previously shown that propofol activates protein kinase C (PKC) and induces its translocation in a subtype-specific manner. The purpose of this study was to identify the PKC domains involved in propofol-induced PKC translocation. The regulatory domains of PKC consist of C1 and C2 domains, and the C1 domain is subdivided into the C1A and C1B subdomains. Mutant PKCα and PKCδ with each domain deleted were fused with green fluorescent protein (GFP) and expressed in HeLa cells. Propofol-induced PKC translocation was observed by time-lapse imaging using a fluorescence microscope. The results showed that persistent propofol-induced PKC translocation to the plasma membrane was abolished by the deletion of both C1 and C2 domains in PKCα and by the deletion of the C1B domain in PKCδ. Therefore, propofol-induced PKC translocation involves the C1 and C2 domains of PKCα and the C1B domain of PKCδ. We also found that treatment with calphostin C, a C1 domain inhibitor, abolished propofol-induced PKCδ translocation. In addition, calphostin C inhibited the propofol-induced phosphorylation of endothelial nitric oxide synthase (eNOS). These results suggest that it may be possible to modulate the exertion of propofol effects by regulating the PKC domains involved in propofol-induced PKC translocation.
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Affiliation(s)
- Soshi Narasaki
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan; Dept of Anesthesiology & Critical Care, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Soma Noguchi
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Tomoaki Urabe
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan; Dept of Anesthesiology & Critical Care, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Kana Harada
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Izumi Hide
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Shigeru Tanaka
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Yuhki Yanase
- Dept of Pharmacotherapy, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Taketoshi Kajimoto
- Div of Biochem, Dept of Biochem and Mol Biol, Kobe Univ Grad Sch of Med, Japan
| | - Kazue Uchida
- Dept of Dermatology, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Yasuo M Tsutsumi
- Dept of Anesthesiology & Critical Care, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan
| | - Norio Sakai
- Dept of Mol & Pharmacol Neurosci, Grad Sch of Biomed & Health Sci, Hiroshima Univ, Japan.
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Han Y, Srinivasan S, Yun CC. Inhibition of protein kinase C-α and activation of ezrin by Lactobacillus acidophilus restore Na +/H + exchange activity and fluid absorption in db/db mice. Am J Physiol Endocrinol Metab 2023; 325:E214-E226. [PMID: 37467022 PMCID: PMC10511175 DOI: 10.1152/ajpendo.00145.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023]
Abstract
Gastrointestinal (GI) complications, including diarrhea, constipation, and gastroparesis, are common in patients with diabetes. Dysregulation of the Na+/H+ exchanger NHE3 in the intestine is linked to diarrhea and constipation, and recent studies showed that NHE3 expression is reduced in type 1 diabetes and metformin causes diarrhea in the db/db mouse model of type 2 diabetes (T2D) via inhibition of NHE3. In this study, we investigated whether NHE3 expression is altered in type 2 diabetic intestine and the underlying mechanism that dysregulates NHE3. NHE3 expression in the brush border membrane (BBM) of the intestine of diabetic mice and humans was decreased. Protein kinase C (PKC) activation is associated with pathologies of diabetes, and immunofluorescence (IF) analysis revealed increased BBM PKCα abundance. Inhibition of PKCα increased NHE3 BBM abundance and NHE3-mediated intestinal fluid absorption in db/db mice. Previous studies have shown that Lactobacillus acidophilus (LA) stimulates intestinal ion transporters. LA increased NHE3 BBM expression and mitigated metformin-mediated inhibition of NHE3 in vitro and in vivo. To understand the underlying mechanism of LA-mediated stimulation of NHE3, we used Caco-2bbe cells overexpressing PKCα that mimic the elevated state of PKCα in T2D. LA diminished PKCα BBM expression, increased phosphorylation of ezrin, and the interaction of NHE3 with NHE regulatory factor 2 (NHERF2). In addition, inhibition of PKCι blocked phosphorylation of ezrin and activation of NHE3 by LA. These findings demonstrate that NHE3 is downregulated in T2D, and LA restores NHE3 expression via regulation of PKCα, PKCι, and ezrin.NEW & NOTEWORTHY We used mouse models of type 2 diabetes (T2D) and human patient-derived samples to show that Na+/H+ exchanger 3 (NHE3) expression is decreased in T2D. We show that protein kinase C-α (PKCα) is activated in diabetes and inhibition of PKCα increased NHE3 expression and mitigates diarrhea. We show that Lactobacillus acidophilus (LA) stimulates NHE3 via inhibition of PKCα and phosphorylation of ezrin.
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Affiliation(s)
- Yiran Han
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - Shanthi Srinivasan
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
| | - C Chris Yun
- Gastroenterology Research, Atlanta Veterans Administration Medical Center, Decatur, Georgia, United States
- Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, United States
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Hernandez-Lara MA, Yadav SK, Conaway S, Shah SD, Penn RB, Deshpande DA. Crosstalk between diacylglycerol kinase and protein kinase A in the regulation of airway smooth muscle cell proliferation. Respir Res 2023; 24:155. [PMID: 37301818 DOI: 10.1186/s12931-023-02465-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
BACKGROUND Diacylglycerol kinase (DGK) regulates intracellular signaling and functions by converting diacylglycerol (DAG) into phosphatidic acid. We previously demonstrated that DGK inhibition attenuates airway smooth muscle (ASM) cell proliferation, however, the mechanisms mediating this effect are not well established. Given the capacity of protein kinase A (PKA) to effect inhibition of ASM cells growth in response to mitogens, we employed multiple molecular and pharmacological approaches to examine the putative role of PKA in the inhibition of mitogen-induced ASM cell proliferation by the small molecular DGK inhibitor I (DGK I). METHODS We assayed cell proliferation using CyQUANT™ NF assay, protein expression and phosphorylation using immunoblotting, and prostaglandin E2 (PGE2) secretion by ELISA. ASM cells stably expressing GFP or PKI-GFP (PKA inhibitory peptide-GFP chimera) were stimulated with platelet-derived growth factor (PDGF), or PDGF + DGK I, and cell proliferation was assessed. RESULTS DGK inhibition reduced ASM cell proliferation in cells expressing GFP, but not in cells expressing PKI-GFP. DGK inhibition increased cyclooxygenase II (COXII) expression and PGE2 secretion over time to promote PKA activation as demonstrated by increased phosphorylation of (PKA substrates) VASP and CREB. COXII expression and PKA activation were significantly decreased in cells pre-treated with pan-PKC (Bis I), MEK (U0126), or ERK2 (Vx11e) inhibitors suggesting a role for PKC and ERK in the COXII-PGE2-mediated activation of PKA signaling by DGK inhibition. CONCLUSIONS Our study provides insight into the molecular pathway (DAG-PKC/ERK-COXII-PGE2-PKA) regulated by DGK in ASM cells and identifies DGK as a potential therapeutic target for mitigating ASM cell proliferation that contributes to airway remodeling in asthma.
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Affiliation(s)
- Miguel A Hernandez-Lara
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Santosh Kumar Yadav
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Stanley Conaway
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Sushrut D Shah
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Raymond B Penn
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Deepak A Deshpande
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
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Chen XR, Igumenova TI. Regulation of eukaryotic protein kinases by Pin1, a peptidyl-prolyl isomerase. Adv Biol Regul 2023; 87:100938. [PMID: 36496344 PMCID: PMC9992314 DOI: 10.1016/j.jbior.2022.100938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
The peptidyl-prolyl isomerase Pin1 cooperates with proline-directed kinases and phosphatases to regulate multiple oncogenic pathways. Pin1 specifically recognizes phosphorylated Ser/Thr-Pro motifs in proteins and catalyzes their cis-trans isomerization. The Pin1-catalyzed conformational changes determine the stability, activity, and subcellular localization of numerous protein substrates. We conducted a survey of eukaryotic protein kinases that are regulated by Pin1 and whose Pin1 binding sites have been identified. Our analyses reveal that Pin1 target sites in kinases do not fall exclusively within the intrinsically disordered regions of these enzymes. Rather, they fall into three groups based on their location: (i) within the catalytic kinase domain, (ii) in the C-terminal kinase region, and (iii) in regulatory domains. Some of the kinases downregulated by Pin1 activity are tumor-suppressing, and all kinases upregulated by Pin1 activity are functionally pro-oncogenic. These findings further reinforce the rationale for developing Pin1-specific inhibitors as attractive pharmaceuticals for cancer therapy.
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Affiliation(s)
- Xiao-Ru Chen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843, USA.
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7
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Chang M, Gada KD, Chidipi B, Tsalatsanis A, Gibbons J, Remily-Wood E, Logothetis DE, Oberstaller J, Noujaim SF. I KACh is constitutively active via PKC epsilon in aging mediated atrial fibrillation. iScience 2022; 25:105442. [PMID: 36388956 PMCID: PMC9650037 DOI: 10.1016/j.isci.2022.105442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 09/22/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
Atrial fibrillation (AF), the most common abnormal heart rhythm, is a major cause for stroke. Aging is a significant risk factor for AF; however, specific ionic pathways that can elucidate how aging leads to AF remain elusive. We used young and old wild-type and PKC epsilon- (PKCϵ) knockout mice, whole animal, and cellular electrophysiology, as well as whole heart, and cellular imaging to investigate how aging leads to the aberrant functioning of a potassium current, and consequently to AF facilitation. Our experiments showed that knocking out PKCϵ abrogates the effects of aging on AF by preventing the development of a constitutively active acetylcholine sensitive inward rectifier potassium current (IKACh). Moreover, blocking this abnormal current in the old heart reduces AF inducibility. Our studies demonstrate that in the aging heart, IKACh is constitutively active in a PKCϵ-dependent manner, contributing to the perpetuation of AF.
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Affiliation(s)
- Mengmeng Chang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Kirin D. Gada
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Science, Bouvé College of Health Sciences, Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Bojjibabu Chidipi
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Athanasios Tsalatsanis
- College of Medicine Office of Research, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Justin Gibbons
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Elizabeth Remily-Wood
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Diomedes E. Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Science, Bouvé College of Health Sciences, Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Jenna Oberstaller
- Center for Global Health and Infectious Diseases Research and USF Genomics Program, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Sami F. Noujaim
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Szondy Z, Al-Zaeed N, Tarban N, Fige É, Garabuczi É, Sarang Z. Involvement of phosphatidylserine receptors in the skeletal muscle regeneration: therapeutic implications. J Cachexia Sarcopenia Muscle 2022; 13:1961-1973. [PMID: 35666022 PMCID: PMC9397555 DOI: 10.1002/jcsm.13024] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 04/09/2022] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
Sarcopenia is a progressive loss of muscle mass and strength with a risk of adverse outcomes such as disability, poor quality of life, and death. Increasing evidence indicates that diminished ability of the muscle to activate satellite cell-dependent regeneration is one of the factors that might contribute to its development. Skeletal muscle regeneration following myogenic cell death results from the proliferation and differentiation of myogenic stem cells, called satellite cells, located beneath the basal lamina of the muscle fibres. Satellite cell differentiation is not a satellite cell-autonomous process but depends on signals provided by the surrounding cells. Infiltrating macrophages play a key role in the process partly by clearing the necrotic cell debris, partly by producing cytokines and growth factors that guide myogenesis. At the beginning of the muscle regeneration process, macrophages are pro-inflammatory, and the cytokines produced by them trigger the proliferation and differentiation of satellite cells. Following the uptake of dead cells, however, a transcriptionally regulated phenotypic change (macrophage polarization) is induced in them resulting in their transformation into healing macrophages that guide resolution of inflammation, completion of myoblast differentiation, myoblast fusion and growth, and return to homeostasis. Impaired efferocytosis results in delayed cell death clearance, delayed macrophage polarization, prolonged inflammation, and impaired muscle regeneration. Thus, proper efferocytosis by macrophages is a determining factor during muscle repair. Here we review that both efferocytosis and myogenesis are dependent on the cell surface phosphatidylserine (PS), and surprisingly, these two processes share a number of common PS receptors and signalling pathways. Based on these findings, we propose that stimulating the function of PS receptors for facilitating muscle repair following injury could be a successful approach, as it would enhance efferocytosis and myogenesis simultaneously. Because increasing evidence indicates a pathophysiological role of impaired efferocytosis in the development of chronic inflammatory conditions, as well as in impaired muscle regeneration both contributing to the development of sarcopenia, improving efferocytosis should be considered also in its management. Again applying or combining those treatments that target PS receptors would be expected to be the most effective, because they would also promote myogenesis. A potential PS receptor-triggering candidate molecule is milk fat globule-EGF-factor 8 (MFG-E8), which not only stimulates PS-dependent efferocytosis and myoblast fusion but also promotes extracellular signal-regulated kinase (ERK) and Akt activation-mediated cell proliferation and cell cycle progression in myoblasts.
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Affiliation(s)
- Zsuzsa Szondy
- Section of Dental Biochemistry, Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary.,Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Nour Al-Zaeed
- Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Nastaran Tarban
- Doctoral School of Molecular Cell and Immune Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Éva Fige
- Section of Dental Biochemistry, Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Éva Garabuczi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsolt Sarang
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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9
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Grauffel C, Weng WH, Lim C. Factors allowing small monovalent Li + to displace Ca 2+ in proteins. Phys Chem Chem Phys 2022; 24:17759-17769. [PMID: 35848546 DOI: 10.1039/d2cp02072f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Because Li+ and Ca2+ differ in both charge and size, the possibility that monovalent Li+ could dislodge the bulkier, divalent Ca2+ in Ca2+ proteins had not been considered. However, our recent density functional theory/continuum dielectric calculations predicted that Li+ could displace the native Ca2+ from the C2 domain of cytosolic PKCα/γ. This would reduce electrostatic interactions between the Li+-bound C2 domain and the membrane, consistent with experimental studies showing that Li+ can inhibit the translocation of cytoplasmic PKC to membranes. Besides the trinuclear Ca2+-site in the PKCα/γ C2 domain, it is not known whether other Ca2+-sites in human proteins may be susceptible to Li+ substitution. Furthermore, it is unclear what factors determine the outcome of the competition between divalent Ca2+ and monovalent Li+. Here we show that the net charge of residues in the first and second coordination shell is a key determinant of the selectivity for divalent Ca2+ over monovalent Li+ in proteins: neutral/anionic Ca2+-carboxylate sites are protected against Li+ attack. They are further protected by outer-shell Asp-/Glu- and the protein matrix rigidifying the Ca2+-site or limiting water entry. In contrast, buried, cationic Ca2+-sites surrounded by Arg+/Lys+, which are found in the C2 domains of PKCα/γ, as well as certain synaptotagmins, are prone to Li+ attack.
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Affiliation(s)
- Cédric Grauffel
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| | - Wei-Hsiang Weng
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan.
| | - Carmay Lim
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan. .,Department of Chemistry, National Tsing Hua University, Hsinchu 300, Taiwan
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10
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Energy Metabolism and Lipidome Are Highly Regulated during Osteogenic Differentiation of Dental Follicle Cells. Stem Cells Int 2022; 2022:3674931. [PMID: 35903407 PMCID: PMC9315453 DOI: 10.1155/2022/3674931] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 06/14/2022] [Accepted: 06/30/2022] [Indexed: 11/18/2022] Open
Abstract
Dental follicle cells (DFCs) are stem/progenitor cells of the periodontium and give rise to alveolar osteoblasts. However, understanding of the molecular mechanisms of osteogenic differentiation, which is required for cell-based therapies, is delimited. This study is aimed at analyzing the energy metabolism during the osteogenic differentiation of DFCs. Human DFCs were cultured, and osteogenic differentiation was induced by either dexamethasone or bone morphogenetic protein 2 (BMP2). Previous microarray data were reanalyzed to examine pathways that are regulated after osteogenic induction. Expression and activity of metabolic markers were evaluated by western blot analysis and specific assays, relative amount of mitochondrial DNA was measured by real-time quantitative polymerase chain reaction, the oxidative state of cells was determined by a glutathione assay, and the lipidome of cells was analyzed via mass spectrometry (MS). Moreover, osteogenic markers were analyzed after the inhibition of fatty acid synthesis by 5-(tetradecyloxy)-2-furoic acid or C75. Pathway enrichment analysis of microarray data revealed that carbon metabolism was amongst the top regulated pathways after osteogenic induction in DFCs. Further analysis showed that enzymes involved in glycolysis, citric acid cycle, mitochondrial activity, and lipid metabolism are differentially expressed during differentiation, with most markers upregulated and more markedly after induction with dexamethasone compared to BMP2. Moreover, the cellular state was more oxidized, and mitochondrial DNA was distinctly upregulated during the second half of differentiation. Besides, MS of the lipidome revealed higher lipid concentrations after osteogenic induction, with a preference for species with lower numbers of C-atoms and double bonds, which indicates a de novo synthesis of lipids. Concordantly, inhibition of fatty acid synthesis impeded the osteogenic differentiation of DFCs. This study demonstrates that energy metabolism is highly regulated during osteogenic differentiation of DFCs including changes in the lipidome suggesting enhanced de novo synthesis of lipids, which are required for the differentiation process.
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11
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Black JD, Affandi T, Black AR, Reyland ME. PKCα and PKCδ: Friends and Rivals. J Biol Chem 2022; 298:102194. [PMID: 35760100 PMCID: PMC9352922 DOI: 10.1016/j.jbc.2022.102194] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/13/2022] [Accepted: 06/21/2022] [Indexed: 01/06/2023] Open
Abstract
PKC comprises a large family of serine/threonine kinases that share a requirement for allosteric activation by lipids. While PKC isoforms have significant homology, functional divergence is evident among subfamilies and between individual PKC isoforms within a subfamily. Here, we highlight these differences by comparing the regulation and function of representative PKC isoforms from the conventional (PKCα) and novel (PKCδ) subfamilies. We discuss how unique structural features of PKCα and PKCδ underlie differences in activation and highlight the similar, divergent, and even opposing biological functions of these kinases. We also consider how PKCα and PKCδ can contribute to pathophysiological conditions and discuss challenges to targeting these kinases therapeutically.
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Affiliation(s)
- Jennifer D Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE.
| | - Trisiani Affandi
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus
| | - Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE
| | - Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus.
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12
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Katti SS, Krieger IV, Ann J, Lee J, Sacchettini JC, Igumenova TI. Structural anatomy of Protein Kinase C C1 domain interactions with diacylglycerol and other agonists. Nat Commun 2022; 13:2695. [PMID: 35577811 PMCID: PMC9110374 DOI: 10.1038/s41467-022-30389-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 04/28/2022] [Indexed: 11/22/2022] Open
Abstract
Diacylglycerol (DAG) is a versatile lipid whose 1,2-sn-stereoisomer serves both as second messenger in signal transduction pathways that control vital cellular processes, and as metabolic precursor for downstream signaling lipids such as phosphatidic acid. Effector proteins translocate to available DAG pools in the membranes by using conserved homology 1 (C1) domains as DAG-sensing modules. Yet, how C1 domains recognize and capture DAG in the complex environment of a biological membrane has remained unresolved for the 40 years since the discovery of Protein Kinase C (PKC) as the first member of the DAG effector cohort. Herein, we report the high-resolution crystal structures of a C1 domain (C1B from PKCδ) complexed to DAG and to each of four potent PKC agonists that produce different biological readouts and that command intense therapeutic interest. This structural information details the mechanisms of stereospecific recognition of DAG by the C1 domains, the functional properties of the lipid-binding site, and the identities of the key residues required for the recognition and capture of DAG and exogenous agonists. Moreover, the structures of the five C1 domain complexes provide the high-resolution guides for the design of agents that modulate the activities of DAG effector proteins.
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Affiliation(s)
- Sachin S. Katti
- grid.264756.40000 0004 4687 2082Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840 USA
| | - Inna V. Krieger
- grid.264756.40000 0004 4687 2082Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840 USA
| | - Jihyae Ann
- grid.31501.360000 0004 0470 5905College of Pharmacy, Seoul National University, Seoul, 08826 Republic of Korea
| | - Jeewoo Lee
- grid.31501.360000 0004 0470 5905College of Pharmacy, Seoul National University, Seoul, 08826 Republic of Korea
| | - James C. Sacchettini
- grid.264756.40000 0004 4687 2082Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840 USA
| | - Tatyana I. Igumenova
- grid.264756.40000 0004 4687 2082Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77840 USA
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13
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Rodgers RL. Glucagon, cyclic AMP, and hepatic glucose mobilization: A half‐century of uncertainty. Physiol Rep 2022; 10:e15263. [PMID: 35569125 PMCID: PMC9107925 DOI: 10.14814/phy2.15263] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/16/2022] [Accepted: 03/18/2022] [Indexed: 12/14/2022] Open
Abstract
For at least 50 years, the prevailing view has been that the adenylate cyclase (AC)/cyclic AMP (cAMP)/protein kinase A pathway is the predominant signal mediating the hepatic glucose‐mobilizing actions of glucagon. A wealth of evidence, however, supports the alternative, that the operative signal most of the time is the phospholipase C (PLC)/inositol‐phosphate (IP3)/calcium/calmodulin pathway. The evidence can be summarized as follows: (1) The consensus threshold glucagon concentration for activating AC ex vivo is 100 pM, but the statistical hepatic portal plasma glucagon concentration range, measured by RIA, is between 28 and 60 pM; (2) Within that physiological concentration range, glucagon stimulates the PLC/IP3 pathway and robustly increases glucose output without affecting the AC/cAMP pathway; (3) Activation of a latent, amplified AC/cAMP pathway at concentrations below 60 pM is very unlikely; and (4) Activation of the PLC/IP3 pathway at physiological concentrations produces intracellular effects that are similar to those produced by activation of the AC/cAMP pathway at concentrations above 100 pM, including elevated intracellular calcium and altered activities and expressions of key enzymes involved in glycogenolysis, gluconeogenesis, and glycogen synthesis. Under metabolically stressful conditions, as in the early neonate or exercising adult, plasma glucagon concentrations often exceed 100 pM, recruiting the AC/cAMP pathway and enhancing the activation of PLC/IP3 pathway to boost glucose output, adaptively meeting the elevated systemic glucose demand. Whether the AC/cAMP pathway is consistently activated in starvation or diabetes is not clear. Because the importance of glucagon in the pathogenesis of diabetes is becoming increasingly evident, it is even more urgent now to resolve lingering uncertainties and definitively establish glucagon’s true mechanism of glycemia regulation in health and disease.
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Affiliation(s)
- Robert L. Rodgers
- Department of Biomedical and Pharmaceutical Sciences College of Pharmacy University of Rhode Island Kingston Rhode Island USA
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14
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OUP accepted manuscript. Hum Mol Genet 2022; 31:2236-2261. [DOI: 10.1093/hmg/ddac029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 11/12/2022] Open
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15
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Grauffel C, Weng WH, Dudev T, Lim C. Trinuclear Calcium Site in the C2 Domain of PKCα/γ Is Prone to Lithium Attack. ACS OMEGA 2021; 6:20657-20666. [PMID: 34396011 PMCID: PMC8359144 DOI: 10.1021/acsomega.1c02882] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/13/2021] [Indexed: 05/10/2023]
Abstract
Lithium (Li+) is the first-line therapy for bipolar disorder and a candidate drug for various diseases such as amyotrophic lateral sclerosis, multiple sclerosis, and stroke. Despite being the captivating subject of many studies, the mechanism of lithium's therapeutic action remains unclear. To date, it has been shown that Li+ competes with Mg2+ and Na+ to normalize the activity of inositol and neurotransmitter-related signaling proteins, respectively. Furthermore, Li+ may co-bind with Mg2+-loaded adenosine or guanosine triphosphate to alter the complex's susceptibility to hydrolysis and mediate cellular signaling. Bipolar disorder patients exhibit abnormally high cytosolic Ca2+ levels and protein kinase C (PKC) hyperactivity that can be downregulated by long-term Li+ treatment. However, the possibility that monovalent Li+ could displace the bulkier divalent Ca2+ and inhibit PKC activity has not been considered. Here, using density functional theory calculations combined with continuum dielectric methods, we show that Li+ may displace the native dication from the positively charged trinuclear site in the C2 domain of cytosolic PKCα/γ. This would affect the membrane-docking ability of cytosolic PKCα/γ and reduce the abnormally high membrane-associated active PKCα/γ levels, thus downregulating the PKC hyperactivity found in bipolar patients.
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Affiliation(s)
- Cédric Grauffel
- Institute of Biomedical
Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Wei-Hsiang Weng
- Institute of Biomedical
Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Todor Dudev
- Faculty of Chemistry and Pharmacy, Sofia University, Sofia 1164, Bulgaria
| | - Carmay Lim
- Institute of Biomedical
Sciences, Academia Sinica, Taipei 115, Taiwan
- Department of Chemistry, National Tsing
Hua University, Hsinchu 300, Taiwan
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16
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da Silva RM, Vital WO, Martins RS, Moraes J, Gomes H, Calixto C, Konnai S, Ohashi K, da Silva Vaz I, Logullo C. Differential expression of PEPCK isoforms is correlated to Aedes aegypti oogenesis and embryogenesis. Comp Biochem Physiol B Biochem Mol Biol 2021; 256:110618. [PMID: 34015437 DOI: 10.1016/j.cbpb.2021.110618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 05/05/2021] [Accepted: 05/14/2021] [Indexed: 11/19/2022]
Abstract
The mosquito Aedes aegypti undertakes a shift in carbohydrate metabolism during embryogenesis, including an increase in the activity of phosphoenolpyruvate carboxykinase (PEPCK), a key gluconeogenic enzyme, at critical steps of embryo development. All eukaryotes studied to date present two PEPCK isoforms, namely PEPCK-M (mitochondrial) and PEPCK-C (cytosolic). In A. aegypti, however, these proteins are so far uncharacterized. In the present work we describe two A. aegypti PEPCK isoforms by sequence alignment, protein modeling, and transcription analysis in different tissues, as well as PEPCK enzymatic activity assays in mitochondrial and cytoplasmic compartments during oogenesis and embryogenesis. First, we characterized the protein sequences compared to other organisms, and identified conserved sites and key amino acids. We also performed structure modeling for AePEPCK(M) and AePEPCK(C), identifying highly conserved structural sites, as well as a signal peptide in AePEPCK(M) localized in a very hydrophobic region. Moreover, after blood meal and during mosquito oogenesis and embryogenesis, both PEPCKs isoforms showed different transcriptional profiles, suggesting that mRNA for the cytosolic form is transmitted maternally, whereas the mitochondrial form is synthesized by the zygote. Collectively, these results improve our understanding of mosquito physiology and may yield putative targets for developing new methods for A. aegypti control.
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Affiliation(s)
- Renato Martins da Silva
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - Wagner Oliveira Vital
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | | | - Jorge Moraes
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | - Helga Gomes
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | - Christiano Calixto
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
| | - Satoru Konnai
- Laboratory of Infectious Diseases, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Kita-ku Sapporo 060-0818, Japan
| | - Kazuhiko Ohashi
- Laboratory of Infectious Diseases, Graduate School of Veterinary Medicine, Hokkaido University, Kita 18, Kita-ku Sapporo 060-0818, Japan
| | - Itabajara da Silva Vaz
- Centro de Biotecnologia and Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Carlos Logullo
- Laboratório Integrado de Bioquímica Hatisaburo Masuda and Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil.
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17
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Junková K, Mirchi LF, Chylíková B, Janků M, Šilhavý J, Hüttl M, Marková I, Miklánková D, Včelák J, Malínská H, Pravenec M, Šeda O, Liška F. Hepatic Transcriptome Profiling Reveals Lack of Acsm3 Expression in Polydactylous Rats with High-Fat Diet-Induced Hypertriglyceridemia and Visceral Fat Accumulation. Nutrients 2021; 13:nu13051462. [PMID: 33923085 PMCID: PMC8147112 DOI: 10.3390/nu13051462] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/20/2021] [Accepted: 04/23/2021] [Indexed: 12/16/2022] Open
Abstract
Metabolic syndrome (MetS) is an important cause of worldwide morbidity and mortality. Its complex pathogenesis includes, on the one hand, sedentary lifestyle and high caloric intake, and, on the other hand, there is a clear genetic predisposition. PD (Polydactylous rat) is an animal model of hypertriglyceridemia, insulin resistance, and obesity. To unravel the genetic and pathophysiologic background of this phenotype, we compared morphometric and metabolic parameters as well as liver transcriptomes among PD, spontaneously hypertensive rat, and Brown Norway (BN) strains fed a high-fat diet (HFD). After 4 weeks of HFD, PD rats displayed marked hypertriglyceridemia but without the expected hepatic steatosis. Moreover, the PD strain showed significant weight gain, including increased weight of retroperitoneal and epididymal fat pads, and impaired glucose tolerance. In the liver transcriptome, we found 5480 differentially expressed genes, which were enriched for pathways involved in fatty acid beta and omega oxidation, glucocorticoid metabolism, oxidative stress, complement activation, triacylglycerol and lipid droplets synthesis, focal adhesion, prostaglandin synthesis, interferon signaling, and tricarboxylic acid cycle pathways. Interestingly, the PD strain, contrary to SHR and BN rats, did not express the Acsm3 (acyl-CoA synthetase medium-chain family member 3) gene in the liver. Together, these results suggest disturbances in fatty acid utilization as a molecular mechanism predisposing PD rats to hypertriglyceridemia and fat accumulation.
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Affiliation(s)
- Kristýna Junková
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
| | - Lukáš F. Mirchi
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
| | - Blanka Chylíková
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
| | - Michaela Janků
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
| | - Jan Šilhavý
- Department of Genetics of Model Diseases, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague, Czech Republic;
| | - Martina Hüttl
- Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.); (H.M.)
| | - Irena Marková
- Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.); (H.M.)
| | - Denisa Miklánková
- Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.); (H.M.)
| | - Josef Včelák
- Institute of Endocrinology, 116 94 Prague, Czech Republic;
| | - Hana Malínská
- Institute for Clinical and Experimental Medicine, 140 21 Prague, Czech Republic; (M.H.); (I.M.); (D.M.); (H.M.)
| | - Michal Pravenec
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
- Department of Genetics of Model Diseases, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague, Czech Republic;
| | - Ondřej Šeda
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
| | - František Liška
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital, 128 00 Prague, Czech Republic; (K.J.); (L.F.M.); (B.C.); (M.J.); (M.P.); (O.Š.)
- Department of Genetics of Model Diseases, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague, Czech Republic;
- Correspondence: ; Tel.: +420-224-968-154
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18
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Pieles O, Reichert TE, Morsczeck C. Classical isoforms of protein kinase C (PKC) and Akt regulate the osteogenic differentiation of human dental follicle cells via both β-catenin and NF-κB. Stem Cell Res Ther 2021; 12:242. [PMID: 33853677 PMCID: PMC8048169 DOI: 10.1186/s13287-021-02313-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/25/2021] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Human dental follicle cells (DFCs) are the precursor cells of the periodontium with a high potential for regenerative therapies of (alveolar) bone. However, the molecular mechanisms of osteogenic differentiation are inadequately understood. Classical isoforms of protein kinase C (PKC) are reported to inhibit osteogenesis of stem/precursor cells. This study evaluated the role of classical PKCs and potential downstream targets on the osteogenic differentiation of DFCs. METHODS DFCs were osteogenic differentiated with dexamethasone or bone morphogenetic protein 2 (BMP2). Expression of PKC and potential upstream/downstream regulators was manipulated using activators, inhibitors, and small interfering ribonucleic acid (siRNA). Expression of proteins was examined by Western blot analysis, while the activation levels of enzymes and transcription factors were examined by their phosphorylation states or by specific activation assays. Expression levels of osteogenic markers were examined by RT-qPCR (reverse transcription-quantitative polymerase chain reaction) analysis. Activity of alkaline phosphatase (ALP) and accumulation of calcium nodules by Alizarin Red staining were measured as indicators of mineralization. RESULTS Classical PKCs like PKCα inhibit the osteogenic differentiation of DFCs, but do not interfere with the induction of differentiation. Inhibition of classical PKCs by Gö6976 enhanced activity of Akt after osteogenic induction. Akt was also regulated during differentiation and especially disturbed BMP2-induced mineralization. The PKC/Akt axis was further shown to regulate the canonical Wnt signaling pathway and eventually nuclear expression of active β-catenin during dexamethasone-induced osteogenesis. Moreover, the nuclear factor "kappa-light-chain-enhancer" of activated B cells (NF-κB) pathway is regulated during osteogenic differentiation of DFCs and via the PKC/Akt axis and disturbs the mineralization. Upstream, parathyroid hormone-related protein (PTHrP) sustained the activity of PKC, while Wnt5a inhibited it. CONCLUSIONS Our results demonstrate that classical PKCs like PKCα and Akt regulate the osteogenic differentiation of DFCs partly via both β-catenin and NF-κB.
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Affiliation(s)
- Oliver Pieles
- Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Torsten E Reichert
- Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Christian Morsczeck
- Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
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19
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Turning the spotlight on the oligosaccharide chain of GM1 ganglioside. Glycoconj J 2021; 38:101-117. [PMID: 33620588 PMCID: PMC7917043 DOI: 10.1007/s10719-021-09974-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 01/23/2021] [Accepted: 01/29/2021] [Indexed: 12/20/2022]
Abstract
It is well over a century that glycosphingolipids are matter of interest in different fields of research. The hydrophilic oligosaccharide and the lipid moiety, the ceramide, both or separately have been considered in different moments as the crucial portion of the molecule, responsible for the role played by the glycosphingolipids associated to the plasma-membranes or to any other subcellular fraction. Glycosphingolipids are a family of compounds characterized by thousands of structures differing in both the oligosaccharide and the ceramide moieties, but among them, the nervous system monosialylated glycosphingolipid GM1, belonging to the group of gangliosides, has gained particular attention by a multitude of Scientists. In recent years, a series of studies have been conducted on the functional roles played by the hydrophilic part of GM1, its oligosaccharide, that we have named “OligoGM1”. These studies allowed to shed new light on the mechanisms underlying the properties of GM1 defining the role of the OligoGM1 in determining precise interactions with membrane proteins instrumental for the neuronal functions, leaving to the ceramide the role of correctly positioning the GM1 in the membrane crucial for the oligosaccharide-protein interactions. In this review we aim to report the recent studies on the cascade of events modulated by OligoGM1, as the bioactive portion of GM1, to support neuronal differentiation and trophism together with preclinical studies on its potential to modify the progression of Parkinson’s disease.
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20
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Katti S, Igumenova TI. Structural insights into C1-ligand interactions: Filling the gaps by in silico methods. Adv Biol Regul 2021; 79:100784. [PMID: 33526356 DOI: 10.1016/j.jbior.2020.100784] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 02/05/2023]
Abstract
Protein Kinase C isoenzymes (PKCs) are the key mediators of the phosphoinositide signaling pathway, which involves regulated hydrolysis of phosphatidylinositol (4,5)-bisphosphate to diacylglycerol (DAG) and inositol-1,4,5-trisphosphate. Dysregulation of PKCs is implicated in many human diseases making this class of enzymes an important therapeutic target. Specifically, the DAG-sensing cysteine-rich conserved homology-1 (C1) domains of PKCs have emerged as promising targets for pharmaceutical modulation. Despite significant progress, the rational design of the C1 modulators remains challenging due to difficulties associated with structure determination of the C1-ligand complexes. Given the dearth of experimental structural data, computationally derived models have been instrumental in providing atomistic insight into the interactions of the C1 domains with PKC agonists. In this review, we provide an overview of the in silico approaches for seven classes of C1 modulators and outline promising future directions.
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Affiliation(s)
- Sachin Katti
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX, 77843, United States
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, TX, 77843, United States.
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21
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Pandey GN, Sharma A, Rizavi HS, Ren X. Dysregulation of Protein Kinase C in Adult Depression and Suicide: Evidence From Postmortem Brain Studies. Int J Neuropsychopharmacol 2021; 24:400-408. [PMID: 33515455 PMCID: PMC8130206 DOI: 10.1093/ijnp/pyab003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/06/2021] [Accepted: 01/27/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Several lines of evidence suggest the abnormalities of protein kinase C (PKC) signaling system in mood disorders and suicide based primarily on the studies of PKC and its isozymes in the platelets and postmortem brain of depressed and suicidal subjects. In this study, we examined the role of PKC isozymes in depression and suicide. METHODS We determined the protein and mRNA expression of various PKC isozymes in the prefrontal cortical region (Brodmann area 9) in 24 normal control subjects, 24 depressed suicide (DS) subjects, and 12 depressed nonsuicide (DNS) subjects. The levels of mRNA in the prefrontal cortex were determined by quantitative real-time reverse transcription PCR, and the protein expression was determined by western blotting. RESULTS We observed a significant decrease in mRNA expression of PKCα, PKCβI, PKCδ, and PKCε and decreased protein expression in either the membrane or the cytosol fraction of PKC isozymes PKCα, PKCβI, PKCβII, and PKCδ in DS and DNS subjects compared with normal control subjects. CONCLUSIONS The current study provides detailed evidence of specific dysregulation of certain PKC isozymes in the postmortem brain of DS and DNS subjects and further supports earlier evidence for the role of PKC in the platelets and brain of the adult and teenage depressed and suicidal population. This comprehensive study may lead to further knowledge of the involvement of PKC in the pathophysiology of depression and suicide.
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Affiliation(s)
- Ghanshyam N Pandey
- University of Illinois at Chicago, Department of Psychiatry, Chicago, IL, USA,Correspondence: Ghanshyam N. Pandey, PhD, University of Illinois at Chicago, 1601 West Taylor Street, Chicago, IL 60612, USA ()
| | - Anuradha Sharma
- University of Illinois at Chicago, Department of Psychiatry, Chicago, IL, USA
| | - Hooriyah S Rizavi
- University of Illinois at Chicago, Department of Psychiatry, Chicago, IL, USA
| | - Xinguo Ren
- University of Illinois at Chicago, Department of Psychiatry, Chicago, IL, USA
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22
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Bowling FZ, Frohman MA, Airola MV. Structure and regulation of human phospholipase D. Adv Biol Regul 2021; 79:100783. [PMID: 33495125 DOI: 10.1016/j.jbior.2020.100783] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/22/2020] [Accepted: 12/28/2020] [Indexed: 12/13/2022]
Abstract
Mammalian phospholipase D (PLD) generates phosphatidic acid, a dynamic lipid secondary messenger involved with a broad spectrum of cellular functions including but not limited to metabolism, migration, and exocytosis. As a promising pharmaceutical target, the biochemical properties of PLD have been well characterized. This has led to the recent crystal structures of human PLD1 and PLD2, the development of PLD specific pharmacological inhibitors, and the identification of cellular regulators of PLD. In this review, we discuss the PLD1 and PLD2 structures, PLD inhibition by small molecules, and the regulation of PLD activity by effector proteins and lipids.
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Affiliation(s)
- Forrest Z Bowling
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Michael V Airola
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, USA.
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Deshpande D, Agarwal N, Fleming T, Gaveriaux-Ruff C, Klose CSN, Tappe-Theodor A, Kuner R, Nawroth P. Loss of POMC-mediated antinociception contributes to painful diabetic neuropathy. Nat Commun 2021; 12:426. [PMID: 33462216 PMCID: PMC7814083 DOI: 10.1038/s41467-020-20677-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
Painful neuropathy is a frequent complication in diabetes. Proopiomelanocortin (POMC) is an endogenous opioid precursor peptide, which plays a protective role against pain. Here, we report dysfunctional POMC-mediated antinociception in sensory neurons in diabetes. In streptozotocin-induced diabetic mice the Pomc promoter is repressed due to increased binding of NF-kB p50 subunit, leading to a loss in basal POMC level in peripheral nerves. Decreased POMC levels are also observed in peripheral nervous system tissue from diabetic patients. The antinociceptive pathway mediated by POMC is further impaired due to lysosomal degradation of μ-opioid receptor (MOR). Importantly, the neuropathic phenotype of the diabetic mice is rescued upon viral overexpression of POMC and MOR in the sensory ganglia. This study identifies an antinociceptive mechanism in the sensory ganglia that paves a way for a potential therapy for diabetic neuropathic pain.
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Affiliation(s)
- Divija Deshpande
- grid.5253.10000 0001 0328 4908Department of Medicine I and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany ,grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, INF 366, Heidelberg, 69120 Germany ,grid.6363.00000 0001 2218 4662Department of Microbiology, Infectious Diseases and Immunology, Charité -Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Nitin Agarwal
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, INF 366, Heidelberg, 69120 Germany
| | - Thomas Fleming
- grid.5253.10000 0001 0328 4908Department of Medicine I and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany ,grid.452622.5German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Claire Gaveriaux-Ruff
- grid.420255.40000 0004 0638 2716Institut de Génétique et de Biologie Moléculaire et Cellulaire, Department of Translational Medicine and Neurogenetics, Illkirch, France ,grid.420255.40000 0004 0638 2716Université de Strasbourg, Illkirch, France ,grid.4444.00000 0001 2112 9282Centre National de la Recherche Scientifique, UMR7104 Illkirch, France ,Institut National de la Santé et de la Recherche Médicale, U1258 Illkirch, France ,grid.418692.00000 0004 0610 0264Ecole Supérieure de Biotechnologie de Strasbourg, Illkirch, France
| | - Christoph S. N. Klose
- grid.6363.00000 0001 2218 4662Department of Microbiology, Infectious Diseases and Immunology, Charité -Universitätsmedizin Berlin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Anke Tappe-Theodor
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, INF 366, Heidelberg, 69120 Germany
| | - Rohini Kuner
- grid.7700.00000 0001 2190 4373Institute of Pharmacology, Heidelberg University, INF 366, Heidelberg, 69120 Germany
| | - Peter Nawroth
- grid.5253.10000 0001 0328 4908Department of Medicine I and Clinical Chemistry, University Hospital of Heidelberg, INF 410 Heidelberg, Germany ,grid.452622.5German Center for Diabetes Research (DZD), Neuherberg, Germany ,Joint Heidelberg-IDC Translational Diabetes Program, Helmholtz Zentrum, 85764 Neuherberg, Germany
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Modulation of calcium signaling depends on the oligosaccharide of GM1 in Neuro2a mouse neuroblastoma cells. Glycoconj J 2020; 37:713-727. [PMID: 33201378 PMCID: PMC7679337 DOI: 10.1007/s10719-020-09963-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 01/02/2023]
Abstract
Recently, we demonstrated that the oligosaccharide portion of ganglioside GM1 is responsible, via direct interaction and activation of the TrkA pathway, for the ability of GM1 to promote neuritogenesis and to confer neuroprotection in Neuro2a mouse neuroblastoma cells. Recalling the knowledge that ganglioside GM1 modulates calcium channels activity, thus regulating the cytosolic calcium concentration necessary for neuronal functions, we investigated if the GM1-oligosaccharide would be able to overlap the GM1 properties in the regulation of calcium signaling, excluding a specific role played by the ceramide moiety inserted into the external layer of plasma membrane. We observed, by calcium imaging, that GM1-oligosaccharide administration to undifferentiated Neuro2a cells resulted in an increased calcium influx, which turned out to be mediated by the activation of TrkA receptor. The biochemical analysis demonstrated that PLCγ and PKC activation follows the TrkA stimulation by GM1-oligosaccharide, leading to the opening of calcium channels both on the plasma membrane and on intracellular storages, as confirmed by calcium imaging experiments performed with IP3 receptor inhibitor. Subsequently, we found that neurite elongation in Neuro2a cells was blocked by subtoxic administration of extracellular and intracellular calcium chelators, suggesting that the increase of intracellular calcium is responsible of GM1-oligosaccharide mediated differentiation. These results suggest that GM1-oligosaccharide is responsible for the regulation of calcium signaling and homeostasis at the base of the neuronal functions mediated by plasma membrane GM1.
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A metabolic reaction-diffusion model for PKCα translocation via PIP2 hydrolysis in an endothelial cell. Biochem J 2020; 477:4071-4084. [PMID: 33026061 DOI: 10.1042/bcj20200484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/08/2020] [Accepted: 10/06/2020] [Indexed: 11/17/2022]
Abstract
Hydrolysis of the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2) at the cell membrane induces the release of inositol 1,4,5-trisphosphate (IP3) into the cytoplasm and diffusion of diacylglycerol (DAG) through the membrane, respectively. Release of IP3 subsequently increases Ca2+ levels in the cytoplasm, which results in activation of protein kinase C α (PKCα) by Ca2+ and DAG, and finally the translocation of PKCα from the cytoplasm to the membrane. In this study, we developed a metabolic reaction-diffusion framework to simulate PKCα translocation via PIP2 hydrolysis in an endothelial cell. A three-dimensional cell model, divided into membrane and cytoplasm domains, was reconstructed from confocal microscopy images. The associated metabolic reactions were divided into their corresponding domain; PIP2 hydrolysis at the membrane domain resulted in DAG diffusion at the membrane domain and IP3 release into the cytoplasm domain. In the cytoplasm domain, Ca2+ was released from the endoplasmic reticulum, and IP3, Ca2+, and PKCα diffused through the cytoplasm. PKCα bound Ca2+ at, and diffused through, the cytoplasm, and was finally activated by binding with DAG at the membrane. Using our model, we analyzed IP3 and DAG dynamics, Ca2+ waves, and PKCα translocation in response to a microscopic stimulus. We found a qualitative agreement between our simulation results and our experimental results obtained by live-cell imaging. Interestingly, our results suggest that PKCα translocation is dominated by DAG dynamics. This three-dimensional reaction-diffusion mathematical framework could be used to investigate the link between PKCα activation in a cell and cell function.
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Chow S, Krainz T, Bettencourt CJ, Broit N, Ferguson B, Zhu M, Hull KG, Pierens GK, Bernhardt PV, Parsons PG, Romo D, Boyle GM, Williams CM. Synthetic Tigliane Intermediates Engage Thiols to Induce Potent Cell Line Selective Anti‐Cancer Activity. Chemistry 2020; 26:13372-13377. [DOI: 10.1002/chem.202003221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/31/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Sharon Chow
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Queensland Australia
| | - Tanja Krainz
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Queensland Australia
| | - Christian J. Bettencourt
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Queensland Australia
| | - Natasa Broit
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 Queensland Australia
| | - Blake Ferguson
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 Queensland Australia
| | - Mingzhao Zhu
- Department of Chemistry and Biochemistry CPRIT Synthesis and Drug-Lead Discovery Laboratory) Baylor University 76798 Waco Texas USA
| | - Kenneth G. Hull
- Department of Chemistry and Biochemistry CPRIT Synthesis and Drug-Lead Discovery Laboratory) Baylor University 76798 Waco Texas USA
| | - Gregory K. Pierens
- Centre for Advanced Imaging The University of Queensland Brisbane 4072 Queensland Australia
| | - Paul V. Bernhardt
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Queensland Australia
| | - Peter G. Parsons
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 Queensland Australia
| | - Daniel Romo
- Department of Chemistry and Biochemistry CPRIT Synthesis and Drug-Lead Discovery Laboratory) Baylor University 76798 Waco Texas USA
| | - Glen M. Boyle
- QIMR Berghofer Medical Research Institute PO Royal Brisbane Hospital Brisbane 4029 Queensland Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 Queensland Australia
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Millner A, Atilla-Gokcumen GE. Lipid Players of Cellular Senescence. Metabolites 2020; 10:metabo10090339. [PMID: 32839400 PMCID: PMC7570155 DOI: 10.3390/metabo10090339] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 01/10/2023] Open
Abstract
Lipids are emerging as key players of senescence. Here, we review the exciting new findings on the diverse roles of lipids in cellular senescence, most of which are enabled by the advancements in omics approaches. Senescence is a cellular process in which the cell undergoes growth arrest while retaining metabolic activity. At the organismal level, senescence contributes to organismal aging and has been linked to numerous diseases. Current research has documented that senescent cells exhibit global alterations in lipid composition, leading to extensive morphological changes through membrane remodeling. Moreover, senescent cells adopt a secretory phenotype, releasing various components to their environment that can affect the surrounding tissue and induce an inflammatory response. All of these changes are membrane and, thus, lipid related. Our work, and that of others, has revealed that fatty acids, sphingolipids, and glycerolipids are involved in the initiation and maintenance of senescence and its associated inflammatory components. These studies opened up an exciting frontier to investigate the deeper mechanistic understanding of the regulation and function of these lipids in senescence. In this review, we will provide a comprehensive snapshot of the current state of the field and share our enthusiasm for the prospect of potential lipid-related protein targets for small-molecule therapy in pathologies involving senescence and its related inflammatory phenotypes.
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Fibroblast growth factor signalling in osteoarthritis and cartilage repair. Nat Rev Rheumatol 2020; 16:547-564. [PMID: 32807927 DOI: 10.1038/s41584-020-0469-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2020] [Indexed: 12/12/2022]
Abstract
Regulated fibroblast growth factor (FGF) signalling is a prerequisite for the correct development and homeostasis of articular cartilage, as evidenced by the fact that aberrant FGF signalling contributes to the maldevelopment of joints and to the onset and progression of osteoarthritis. Of the four FGF receptors (FGFRs 1-4), FGFR1 and FGFR3 are strongly implicated in osteoarthritis, and FGFR1 antagonists, as well as agonists of FGFR3, have shown therapeutic efficacy in mouse models of spontaneous and surgically induced osteoarthritis. FGF18, a high affinity ligand for FGFR3, is the only FGF-based drug currently in clinical trials for osteoarthritis. This Review covers the latest advances in our understanding of the molecular mechanisms that regulate FGF signalling during normal joint development and in the pathogenesis of osteoarthritis. Strategies for FGF signalling-based treatment of osteoarthritis and for cartilage repair in animal models and clinical trials are also introduced. An improved understanding of FGF signalling from a structural biology perspective, and of its roles in skeletal development and diseases, could unlock new avenues for discovery of modulators of FGF signalling that can slow or stop the progression of osteoarthritis.
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Schinner C, Olivares-Florez S, Schlipp A, Trenz S, Feinendegen M, Flaswinkel H, Kempf E, Egu DT, Yeruva S, Waschke J. The inotropic agent digitoxin strengthens desmosomal adhesion in cardiac myocytes in an ERK1/2-dependent manner. Basic Res Cardiol 2020; 115:46. [PMID: 32556797 PMCID: PMC7299919 DOI: 10.1007/s00395-020-0805-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 06/05/2020] [Indexed: 01/28/2023]
Abstract
Desmosomal proteins are components of the intercalated disc and mediate cardiac myocyte adhesion. Enhancement of cardiac myocyte cohesion, referred to as "positive adhesiotropy", was demonstrated to be a function of sympathetic signaling and to be relevant for a sufficient inotropic response. We used the inotropic agent digitoxin to investigate the link between inotropy and adhesiotropy. In contrast to wild-type hearts, digitoxin failed to enhance pulse pressure in perfused mice hearts lacking the desmosomal protein plakoglobin which was paralleled with abrogation of plaque thickening indicating that positive inotropic response requires intact desmosomal adhesion. Atomic force microscopy revealed that digitoxin increased the binding force of the adhesion molecule desmoglein-2 at cell-cell contact areas. This was paralleled by enhanced cardiac myocyte cohesion in both HL-1 cardiac myocytes and murine cardiac slices as determined by dissociation assays as well as by accumulation of desmosomal proteins at cell-cell contact areas. However, total protein levels or cytoskeletal anchorage were not affected. siRNA-mediated depletion of desmosomal proteins abrogated increase of cell cohesion demonstrating that intact desmosomal adhesion is required for positive adhesiotropy. Mechanistically, digitoxin caused activation of ERK1/2. In line with this, inhibition of ERK1/2 signaling abrogated the effects of digitoxin on cell-cell adhesion and desmosomal reorganization. These results show that the positive inotropic agent digitoxin enhances cardiac myocyte cohesion with reorganization of desmosomal proteins in an ERK1/2-dependent manner. Desmosomal adhesion seems to be important for a sufficient positive inotropic response of digitoxin treatment, which can be of medical relevance for the treatment of heart failure.
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Affiliation(s)
- Camilla Schinner
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Silvana Olivares-Florez
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Angela Schlipp
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Sebastian Trenz
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Manouk Feinendegen
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Heinrich Flaswinkel
- Department of Biology II, Ludwig-Maximilians-Universität (LMU) Munich, Munich, Germany
| | - Ellen Kempf
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Desalegn Tadesse Egu
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Sunil Yeruva
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany
| | - Jens Waschke
- Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) Munich, Pettenkoferstraße 11, 80336, Munich, Germany.
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Carriba P, Davies AM. How CD40L reverse signaling regulates axon and dendrite growth. Cell Mol Life Sci 2020; 78:1065-1083. [PMID: 32506167 PMCID: PMC7897621 DOI: 10.1007/s00018-020-03563-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/01/2020] [Accepted: 05/25/2020] [Indexed: 12/18/2022]
Abstract
CD40-activated CD40L reverse signaling is a major physiological regulator of axon and dendrite growth from developing hippocampal pyramidal neurons. Here we have studied how CD40L-mediated reverse signaling promotes the growth of these processes. Cultures of hippocampal pyramidal neurons were established from Cd40-/- mouse embryos to eliminate endogenous CD40/CD40L signaling, and CD40L reverse signaling was stimulated by a CD40-Fc chimera. CD40L reverse signaling increased phosphorylation and hence activation of proteins in the PKC, ERK, and JNK signaling pathways. Pharmacological activators and inhibitors of these pathways revealed that whereas activation of JNK inhibited growth, activation of PKC and ERK1/ERK2 enhanced growth. Experiments using combinations of pharmacological reagents revealed that these signaling pathways regulate growth by functioning as an interconnected and interdependent network rather than acting in a simple linear sequence. Immunoprecipitation studies suggested that stimulation of CD40L reverse signaling generated a receptor complex comprising CD40L, PKCβ, and the Syk tyrosine kinase. Our studies have begun to elucidate the molecular network and interactions that promote axon and dendrite growth from developing hippocampal neurons following activation of CD40L reverse signaling.
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Affiliation(s)
- Paulina Carriba
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, Wales.
| | - Alun M Davies
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, Wales
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Novel mutant mouse line emphasizes the importance of protein kinase C theta for CD4 + T lymphocyte activation. Cell Commun Signal 2019; 17:56. [PMID: 31138259 PMCID: PMC6537413 DOI: 10.1186/s12964-019-0364-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/14/2019] [Indexed: 11/10/2022] Open
Abstract
Background The protein kinase C theta (PKCθ) has an important and non-redundant function downstream of the antigen receptor and co-receptor complex in T lymphocytes. PKCθ is not only essential for activation of NF-κB, AP-1 and NFAT and subsequent interleukin-2 expression, but also critical for positive selection and development of regulatory T lymphocytes in the thymus. Several domains regulate its activity, such as a pseudosubstrate sequence mediating an auto-inhibitory intramolecular interaction, the tandem C1 domains binding diacylglycerol, and phosphorylation at conserved tyrosine, threonine as well as serine residues throughout the whole length of the protein. To address the importance of the variable domain V1 at the very N-terminus, which is encoded by exon 2, a mutated version of PKCθ was analyzed for its ability to stimulate T lymphocyte activation. Methods T cell responses were analyzed with promoter luciferase reporter assays in Jurkat T cells transfected with PKCθ expression constructs. A mouse line expressing mutated instead of wild type PKCθ was analyzed in comparison to PKCθ-deficient and wild type mice for thymic development and T cell subsets by flow cytometry and T cell activation by quantitative RT-PCR, luminex analysis and flow cytometry. Results In cell lines, the exon 2-replacing mutation impaired the transactivation of interleukin-2 expression by constitutively active mutant form of PKCθ. Moreover, analysis of a newly generated exon 2-mutant mouse line (PKCθ-E2mut) revealed that the N-terminal replacement mutation results in an hypomorph mutant of PKCθ combined with reduced PKCθ protein levels in CD4+ T lymphocytes. Thus, PKCθ-dependent functions in T lymphocytes were affected resulting in impaired thymic development of single positive T lymphocytes in vivo. In particular, there was diminished generation of regulatory T lymphocytes. Furthermore, early activation responses such as interleukin-2 expression of CD4+ T lymphocytes were significantly reduced even though cell viability was not affected. Thus, PKCθ-E2mut mice show a phenotype similar to conventional PKCθ-deficient mice. Conclusion Taken together, PKCθ-E2mut mice show a phenotype similar to conventional PKCθ-deficient mice. Both our in vitro T cell culture experiments and ex vivo analyses of a PKCθ-E2-mutant mouse line independently validate the importance of PKCθ downstream of the antigen-receptor complex for activation of CD4+ T lymphocytes. Electronic supplementary material The online version of this article (10.1186/s12964-019-0364-0) contains supplementary material, which is available to authorized users.
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Siegmund K, Thuille N, Posch N, Fresser F, Leitges M, Baier G. Novel mutant mouse line emphasizes the importance of protein kinase C theta for CD4 + T lymphocyte activation. Cell Commun Signal 2019. [PMID: 31138259 PMCID: PMC6537413 DOI: 10.1186/s12964-019-0364-0#] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The protein kinase C theta (PKCθ) has an important and non-redundant function downstream of the antigen receptor and co-receptor complex in T lymphocytes. PKCθ is not only essential for activation of NF-κB, AP-1 and NFAT and subsequent interleukin-2 expression, but also critical for positive selection and development of regulatory T lymphocytes in the thymus. Several domains regulate its activity, such as a pseudosubstrate sequence mediating an auto-inhibitory intramolecular interaction, the tandem C1 domains binding diacylglycerol, and phosphorylation at conserved tyrosine, threonine as well as serine residues throughout the whole length of the protein. To address the importance of the variable domain V1 at the very N-terminus, which is encoded by exon 2, a mutated version of PKCθ was analyzed for its ability to stimulate T lymphocyte activation. METHODS T cell responses were analyzed with promoter luciferase reporter assays in Jurkat T cells transfected with PKCθ expression constructs. A mouse line expressing mutated instead of wild type PKCθ was analyzed in comparison to PKCθ-deficient and wild type mice for thymic development and T cell subsets by flow cytometry and T cell activation by quantitative RT-PCR, luminex analysis and flow cytometry. RESULTS In cell lines, the exon 2-replacing mutation impaired the transactivation of interleukin-2 expression by constitutively active mutant form of PKCθ. Moreover, analysis of a newly generated exon 2-mutant mouse line (PKCθ-E2mut) revealed that the N-terminal replacement mutation results in an hypomorph mutant of PKCθ combined with reduced PKCθ protein levels in CD4+ T lymphocytes. Thus, PKCθ-dependent functions in T lymphocytes were affected resulting in impaired thymic development of single positive T lymphocytes in vivo. In particular, there was diminished generation of regulatory T lymphocytes. Furthermore, early activation responses such as interleukin-2 expression of CD4+ T lymphocytes were significantly reduced even though cell viability was not affected. Thus, PKCθ-E2mut mice show a phenotype similar to conventional PKCθ-deficient mice. CONCLUSION Taken together, PKCθ-E2mut mice show a phenotype similar to conventional PKCθ-deficient mice. Both our in vitro T cell culture experiments and ex vivo analyses of a PKCθ-E2-mutant mouse line independently validate the importance of PKCθ downstream of the antigen-receptor complex for activation of CD4+ T lymphocytes.
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Affiliation(s)
- Kerstin Siegmund
- 0000 0000 8853 2677grid.5361.1Department for Pharmacology and Genetics, Medical University Innsbruck, Division of Translational Cell Genetics, Peter Mayr Str. 1a, A-6020 Innsbruck, Austria
| | - Nikolaus Thuille
- 0000 0000 8853 2677grid.5361.1Department for Pharmacology and Genetics, Medical University Innsbruck, Division of Translational Cell Genetics, Peter Mayr Str. 1a, A-6020 Innsbruck, Austria
| | - Nina Posch
- 0000 0000 8853 2677grid.5361.1Department for Pharmacology and Genetics, Medical University Innsbruck, Division of Translational Cell Genetics, Peter Mayr Str. 1a, A-6020 Innsbruck, Austria
| | - Friedrich Fresser
- 0000 0000 8853 2677grid.5361.1Department for Pharmacology and Genetics, Medical University Innsbruck, Division of Translational Cell Genetics, Peter Mayr Str. 1a, A-6020 Innsbruck, Austria
| | | | - Gottfried Baier
- 0000 0000 8853 2677grid.5361.1Department for Pharmacology and Genetics, Medical University Innsbruck, Division of Translational Cell Genetics, Peter Mayr Str. 1a, A-6020 Innsbruck, Austria
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Cooke M, Casado-Medrano V, Ann J, Lee J, Blumberg PM, Abba MC, Kazanietz MG. Differential Regulation of Gene Expression in Lung Cancer Cells by Diacyglycerol-Lactones and a Phorbol Ester Via Selective Activation of Protein Kinase C Isozymes. Sci Rep 2019; 9:6041. [PMID: 30988374 PMCID: PMC6465381 DOI: 10.1038/s41598-019-42581-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/29/2019] [Indexed: 02/06/2023] Open
Abstract
Despite our extensive knowledge on the biology of protein kinase C (PKC) and its involvement in disease, limited success has been attained in the generation of PKC isozyme-specific modulators acting via the C1 domain, the binding site for the lipid second messenger diacylglycerol (DAG) and the phorbol ester tumor promoters. Synthetic efforts had recently led to the identification of AJH-836, a DAG-lactone with preferential affinity for novel isozymes (nPKCs) relative to classical PKCs (cPKCs). Here, we compared the ability of AJH-836 and a prototypical phorbol ester (phorbol 12-myristate 13-acetate, PMA) to induce changes in gene expression in a lung cancer model. Gene profiling analysis using RNA-Seq revealed that PMA caused major changes in gene expression, whereas AJH-836 only induced a small subset of genes, thus providing a strong indication for a major involvement of cPKCs in their control of gene expression. MMP1, MMP9, and MMP10 were among the genes most prominently induced by PMA, an effect impaired by RNAi silencing of PKCα, but not PKCδ or PKCε. Comprehensive gene signature analysis and bioinformatics efforts, including functional enrichment and transcription factor binding site analyses of dysregulated genes, identified major differences in pathway activation and transcriptional networks between PMA and DAG-lactones. In addition to providing solid evidence for the differential involvement of individual PKC isozymes in the control of gene expression, our studies emphasize the importance of generating targeted C1 domain ligands capable of differentially regulating PKC isozyme-specific function in cellular models.
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Affiliation(s)
- Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Victoria Casado-Medrano
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jihyae Ann
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jeewoo Lee
- Laboratory of Medicinal Chemistry, College of Pharmacy, Seoul National University, Seoul, 08826, Republic of Korea
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, NCI, Bethesda, MD, 20892, USA
| | - Martin C Abba
- Centro de Investigaciones Inmunológicas Básicas y Aplicadas, Universidad Nacional de La Plata, CP1900, La Plata, Argentina.
| | - Marcelo G Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Yang Y, Shu C, Li P, Igumenova TI. Structural Basis of Protein Kinase Cα Regulation by the C-Terminal Tail. Biophys J 2019; 114:1590-1603. [PMID: 29642029 DOI: 10.1016/j.bpj.2017.12.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 12/07/2017] [Accepted: 12/21/2017] [Indexed: 10/17/2022] Open
Abstract
Protein kinase C (PKC) isoenzymes are multi-modular proteins activated at the membrane surface to regulate signal transduction processes. When activated by second messengers, PKC undergoes a drastic conformational and spatial transition from the inactive cytosolic state to the activated membrane-bound state. The complete structure of either state of PKC remains elusive. We demonstrate, using NMR spectroscopy, that the isolated Ca2+-sensing membrane-binding C2 domain of the conventional PKCα interacts with a conserved hydrophobic motif of the kinase C-terminal region, and we report a structural model of the complex. Our data suggest that the C-terminal region plays a dual role in regulating the PKC activity: activating, through sensitization of PKC to intracellular Ca2+ oscillations; and auto-inhibitory, through its interaction with a conserved positively charged region of the C2 domain.
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Affiliation(s)
- Yuan Yang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Chang Shu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Pingwei Li
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
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35
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Unc13: a multifunctional synaptic marvel. Curr Opin Neurobiol 2019; 57:17-25. [PMID: 30690332 DOI: 10.1016/j.conb.2018.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/16/2022]
Abstract
Nervous systems are built on synaptic connections, and our understanding of these complex compartments has deepened over the past quarter century as the diverse fields of genetics, molecular biology, physiology, and biochemistry each made significant in-roads into synaptic function. On the presynaptic side, an evolutionarily conserved core fusion apparatus constructed from a handful of proteins has emerged, with Unc13 serving as a hub that coordinates nearly every aspect of synaptic transmission. This review briefly highlights recent studies on diverse aspects of Unc13 function including roles in SNARE assembly and quality control, release site building, calcium channel proximity, and short-term synaptic plasticity.
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36
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Abstract
Protein kinase C (PKC) isozymes belong to a family of Ser/Thr kinases whose activity is governed by reversible release of an autoinhibitory pseudosubstrate. For conventional and novel isozymes, this is effected by binding the lipid second messenger, diacylglycerol, but for atypical PKC isozymes, this is effected by binding protein scaffolds. PKC shot into the limelight following the discovery in the 1980s that the diacylglycerol-sensitive isozymes are "receptors" for the potent tumor-promoting phorbol esters. This set in place a concept that PKC isozymes are oncoproteins. Yet three decades of cancer clinical trials targeting PKC with inhibitors failed and, in some cases, worsened patient outcome. Emerging evidence from cancer-associated mutations and protein expression levels provide a reason: PKC isozymes generally function as tumor suppressors and their activity should be restored, not inhibited, in cancer therapies. And whereas not enough activity is associated with cancer, variants with enhanced activity are associated with degenerative diseases such as Alzheimer's disease. This review describes the tightly controlled mechanisms that ensure PKC activity is perfectly balanced and what happens when these controls are deregulated. PKC isozymes serve as a paradigm for the wisdom of Confucius: "to go beyond is as wrong as to fall short."
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Affiliation(s)
- Alexandra C Newton
- a Department of Pharmacology , University of California at San Diego , La Jolla , CA , USA
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37
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Roberts MF, Khan HM, Goldstein R, Reuter N, Gershenson A. Search and Subvert: Minimalist Bacterial Phosphatidylinositol-Specific Phospholipase C Enzymes. Chem Rev 2018; 118:8435-8473. [DOI: 10.1021/acs.chemrev.8b00208] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Mary F. Roberts
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Rebecca Goldstein
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | | | - Anne Gershenson
- Department of Biochemistry and Molecular Biology, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
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38
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Tanghe G, Urwyler-Rösselet C, De Groote P, Dejardin E, De Bock PJ, Gevaert K, Vandenabeele P, Declercq W. RIPK4 activity in keratinocytes is controlled by the SCF β-TrCP ubiquitin ligase to maintain cortical actin organization. Cell Mol Life Sci 2018; 75:2827-2841. [PMID: 29435596 PMCID: PMC11105318 DOI: 10.1007/s00018-018-2763-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/22/2018] [Accepted: 01/25/2018] [Indexed: 01/20/2023]
Abstract
RIPK4 is a key player in epidermal differentiation and barrier formation. RIPK4 signaling pathways controlling keratinocyte proliferation and differentiation depend on its kinase activity leading to Dvl2, Pkp1 and IRF6 phosphorylation and NF-κB activation. However, the mechanism regulating RIPK4 activity levels remains elusive. We show that cultured keratinocytes display constitutive active phosphorylated RIPK4 while PKC signaling can trigger RIPK4 activation in various non-keratinocyte cell lines, in which RIPK4 is present in a non-phosphorylated state. Interestingly, we identified the SCFβ-TrCP ubiquitin E3 ligase complex responsible for regulating the active RIPK4 protein level. The SCFβ-TrCP complex binds to a conserved phosphodegron motif in the intermediate domain of RIPK4, subsequently leading to K48-linked ubiquitinylation and degradation. The recruitment of β-TrCP is dependent on RIPK4 activation and trans-autophosphorylation. β-TrCP knock-down resulted in RIPK4-dependent formation of actin stress fibers, cell scattering and increased cell motility, suggesting that tight control of RIPK4 activity levels is crucial to maintain cell shape and behavior in keratinocytes.
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Affiliation(s)
- Giel Tanghe
- Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Technologiepark 927, 9052, Gent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Corinne Urwyler-Rösselet
- Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Technologiepark 927, 9052, Gent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- Department of Biology, Institute of Molecular Health Sciences, ETH Zurich, Zurich, Switzerland
| | - Philippe De Groote
- Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Technologiepark 927, 9052, Gent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Emmanuel Dejardin
- Laboratory of Molecular Immunology and Signal Transduction, GIGA-Institute, University of Liège, Liège, Belgium
| | - Pieter-Jan De Bock
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, Ghent, Belgium
- Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Peter Vandenabeele
- Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Technologiepark 927, 9052, Gent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Wim Declercq
- Molecular Signaling and Cell Death Unit, VIB-UGent Center for Inflammation Research, Technologiepark 927, 9052, Gent, Belgium.
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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39
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Cummins TJ, Kedei N, Czikora A, Lewin NE, Kirk S, Petersen ME, McGowan KM, Chen JQ, Luo X, Johnson RC, Ravichandran S, Blumberg PM, Keck GE. Synthesis and Biological Evaluation of Fluorescent Bryostatin Analogues. Chembiochem 2018; 19:877-889. [PMID: 29424951 DOI: 10.1002/cbic.201700655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Indexed: 11/10/2022]
Abstract
To investigate the cellular distribution of tumor-promoting vs. non-tumor-promoting bryostatin analogues, we synthesized fluorescently labeled variants of two bryostatin derivatives that have previously shown either phorbol ester-like or bryostatin-like biological activity in U937 leukemia cells. These new fluorescent analogues both displayed high affinity for protein kinase C (PKC) binding and retained the basic properties of the parent unlabeled compounds in U937 assays. The fluorescent compounds showed similar patterns of intracellular distribution in cells, however; this argues against an existing hypothesis that various patterns of intracellular distribution are responsible for differences in biological activity. Upon further characterization, the fluorescent compounds revealed a slow rate of cellular uptake; correspondingly, they showed reduced activity for cellular responses that were only transient upon treatment with phorbol ester or bryostatin 1.
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Affiliation(s)
- Thomas J Cummins
- University of Utah, Department of Chemistry, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 4048, Bethesda, MD, 20892, USA
| | - Agnes Czikora
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 4048, Bethesda, MD, 20892, USA
| | - Nancy E Lewin
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 4048, Bethesda, MD, 20892, USA
| | - Sharon Kirk
- University of Utah, Department of Chemistry, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA
| | - Mark E Petersen
- University of Utah, Department of Chemistry, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA
| | - Kevin M McGowan
- University of Utah, Department of Chemistry, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA
| | - Jin-Qiu Chen
- Collaborative Protein Technology Resource, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 1044, Bethesda, MD, 20892, USA
| | - Xiaoling Luo
- Collaborative Protein Technology Resource, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 1044, Bethesda, MD, 20892, USA
| | - Randall C Johnson
- Advanced Biomedical and Computational Sciences Biomedical Informatics, and Data Science (BIDS), Directorate Frederick National Laboratory for Cancer Research (FNLCR), Leidos Biomedical Research, Inc., Building 430, Miller Drive, Fort Detrick, Frederick, MD, 21702, USA
| | - Sarangan Ravichandran
- Advanced Biomedical and Computational Sciences Biomedical Informatics, and Data Science (BIDS), Directorate Frederick National Laboratory for Cancer Research (FNLCR), Leidos Biomedical Research, Inc., Building 430, Miller Drive, Fort Detrick, Frederick, MD, 21702, USA
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Room 4048, Bethesda, MD, 20892, USA
| | - Gary E Keck
- University of Utah, Department of Chemistry, 315 South 1400 East, Room 2020, Salt Lake City, UT, 84112, USA
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40
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de la Fuente C, Pinkham C, Dabbagh D, Beitzel B, Garrison A, Palacios G, Hodge KA, Petricoin EF, Schmaljohn C, Campbell CE, Narayanan A, Kehn-Hall K. Phosphoproteomic analysis reveals Smad protein family activation following Rift Valley fever virus infection. PLoS One 2018; 13:e0191983. [PMID: 29408900 PMCID: PMC5800665 DOI: 10.1371/journal.pone.0191983] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/15/2018] [Indexed: 01/07/2023] Open
Abstract
Rift Valley fever virus (RVFV) infects both ruminants and humans leading to a wide variance of pathologies dependent on host background and age. Utilizing a targeted reverse phase protein array (RPPA) to define changes in signaling cascades after in vitro infection of human cells with virulent and attenuated RVFV strains, we observed high phosphorylation of Smad transcription factors. This evolutionarily conserved family is phosphorylated by and transduces the activation of TGF-β superfamily receptors. Moreover, we observed that phosphorylation of Smad proteins required active RVFV replication and loss of NSs impaired this activation, further corroborating the RPPA results. Gene promoter analysis of transcripts altered after RVFV infection identified 913 genes that contained a Smad-response element. Functional annotation of these potential Smad-regulated genes clustered in axonal guidance, hepatic fibrosis and cell signaling pathways involved in cellular adhesion/migration, calcium influx, and cytoskeletal reorganization. Furthermore, chromatin immunoprecipitation confirmed the presence of a Smad complex on the interleukin 1 receptor type 2 (IL1R2) promoter, which acts as a decoy receptor for IL-1 activation.
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Affiliation(s)
- Cynthia de la Fuente
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Chelsea Pinkham
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Deemah Dabbagh
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Brett Beitzel
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Aura Garrison
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Gustavo Palacios
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Kimberley Alex Hodge
- Center for Applied Proteomics and Molecular Medicine, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Emanuel F. Petricoin
- Center for Applied Proteomics and Molecular Medicine, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Connie Schmaljohn
- United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | | | - Aarthi Narayanan
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Kylene Kehn-Hall
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
- * E-mail:
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41
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Yang H, Staveness D, Ryckbosch SM, Axtman AD, Loy BA, Barnes AB, Pande VS, Schaefer J, Wender PA, Cegelski L. REDOR NMR Reveals Multiple Conformers for a Protein Kinase C Ligand in a Membrane Environment. ACS CENTRAL SCIENCE 2018; 4:89-96. [PMID: 29392180 PMCID: PMC5785774 DOI: 10.1021/acscentsci.7b00475] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 05/05/2023]
Abstract
Bryostatin 1 (henceforth bryostatin) is in clinical trials for the treatment of Alzheimer's disease and for HIV/AIDS eradication. It is also a preclinical lead for cancer immunotherapy and other therapeutic indications. Yet nothing is known about the conformation of bryostatin bound to its protein kinase C (PKC) target in a membrane microenvironment. As a result, efforts to design more efficacious, better tolerated, or more synthetically accessible ligands have been limited to structures that do not include PKC or membrane effects known to influence PKC-ligand binding. This problem extends more generally to many membrane-associated proteins in the human proteome. Here, we use rotational-echo double-resonance (REDOR) solid-state NMR to determine the conformations of PKC modulators bound to the PKCδ-C1b domain in the presence of phospholipid vesicles. The conformationally limited PKC modulator phorbol diacetate (PDAc) is used as an initial test substrate. While unanticipated partitioning of PDAc between an immobilized protein-bound state and a mobile state in the phospholipid assembly was observed, a single conformation in the bound state was identified. In striking contrast, a bryostatin analogue (bryolog) was found to exist exclusively in a protein-bound state, but adopts a distribution of conformations as defined by three independent distance measurements. The detection of multiple PKCδ-C1b-bound bryolog conformers in a functionally relevant phospholipid complex reveals the inherent dynamic nature of cellular systems that is not captured with single-conformation static structures. These results indicate that binding, selectivity, and function of PKC modulators, as well as the design of new modulators, are best addressed using a dynamic multistate model, an analysis potentially applicable to other membrane-associated proteins.
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Affiliation(s)
- Hao Yang
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Daryl Staveness
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven M. Ryckbosch
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alison D. Axtman
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Brian A. Loy
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander B. Barnes
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Vijay S. Pande
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jacob Schaefer
- Department
of Chemistry, Washington University in St.
Louis, St. Louis, Missouri 63130, United
States
| | - Paul A. Wender
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
- Department
of Chemical and Systems Biology, Stanford
University, Stanford, California 94305, United States
| | - Lynette Cegelski
- Department
of Chemistry, Stanford University, Stanford, California 94305, United States
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42
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Zheng J, Wang Y, Han S, Luo Y, Sun X, Zhu N, Zhao L, Li J. Identification of Protein Kinase C Isoforms Involved in Type 1 Diabetic Encephalopathy in Mice. J Diabetes Res 2018; 2018:8431249. [PMID: 29744369 PMCID: PMC5878894 DOI: 10.1155/2018/8431249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/23/2018] [Indexed: 12/12/2022] Open
Abstract
Diabetic encephalopathy is a complication of diabetes mellitus characterized by impaired cognitive functions. Protein kinase C (PKC) isoforms are rarely reported on diabetic encephalopathy, although they have been believed to play crucial roles in other diabetic complications. In this study, streptozotocin- (STZ-) induced diabetic mice were found to exhibit learning and memory deficits in the Morris water maze test. Meanwhile, the expression of cPKCβII, nPKCε, and cPKCγ did not change in the hippocampus, cortex, and striatum at 2 and 8 weeks after STZ injection. The nPKCε translocation to the membrane, where it is activated, was not altered in the above brain regions at 2 and 8 weeks after STZ injection. Nevertheless, cPKCβII translocation to the membrane was significantly decreased in the cortex and hippocampus at 8 weeks after STZ injection. The translocation of cPKCγ from the cytosol to the membrane was remarkably decreased in the hippocampus at 2 and 8 weeks and in the cortex and striatum at 8 weeks after STZ injection. In addition, deletion of cPKCγ aggravated the impairment of spatial learning and memory. In conclusion, our results suggest that the decrease in the activity of cPKCβII and cPKCγ, especially cPKCγ, may play key roles in the pathogenesis of diabetic encephalopathy.
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Affiliation(s)
- Jiayin Zheng
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Yue Wang
- Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Song Han
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Yanlin Luo
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Xiuli Sun
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Ning Zhu
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Li Zhao
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
| | - Junfa Li
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
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43
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Kasten-Jolly J, Lawrence DA. The cationic (calcium and lead) and enzyme conundrum. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2018; 21:400-413. [PMID: 30917763 DOI: 10.1080/10937404.2019.1592728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The environmental toxicant lead (Pb) and the essential element calcium (Ca) play an interactive role in extracellular and intracellular regulatory functions that affect health. Lead's usurping calcium binding sites, as well as its interactions with thiols and phosphates have been suggested to be the basis for adverse effects on many organ systems especially the nervous system. Among regulatory processes controlled by Ca are calmodulin-dependent phosphodiesterase, calmodulin-dependent protein kinases, calmodulin inhibitor sensitive potassium channels, and calmodulin-independent protein kinase C (PKC) activation. This review focused on Pb studies describing the modulation of PKC, which is also regulated by steroids. Steroid hormone regulation may relate to a focal point for the sex differences of Pb and cellular signaling events. Picomolar concentrations of Pb may stimulate partially purified PKC, but higher concentrations inhibit activity. Although knowledge exists regarding Pb and PKC isoforms, especially interaction of Pb with the purified enzyme, there are conflicting reports concerning metal-mediated activation or inhibition of PKC and downstream signaling events. The effect of Pb on PKC in vivo remains elusive. Most reports of Pb and PKC in whole animal and human studies indicated that Pb either inhibits PKC or exerts no significant effect. However, most of the animal studies were performed with males. Recent studies performed with females and males separately revealed that females and males respond to Pb quite differently, and for this reason, it is suggested that future Pb studies of PKC and other biomedical investigations be performed with females and males.
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Affiliation(s)
- Jane Kasten-Jolly
- a New York State Department of Health , Wadsworth Center , Albany , NY , USA
| | - David A Lawrence
- a New York State Department of Health , Wadsworth Center , Albany , NY , USA
- b Department of Environmental Health Sciences , University at Albany School of Public Health , Rensselaer , NY , USA
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44
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Michelassi F, Liu H, Hu Z, Dittman JS. A C1-C2 Module in Munc13 Inhibits Calcium-Dependent Neurotransmitter Release. Neuron 2017; 95:577-590.e5. [PMID: 28772122 DOI: 10.1016/j.neuron.2017.07.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 05/22/2017] [Accepted: 07/13/2017] [Indexed: 02/08/2023]
Abstract
Almost all known forms of fast chemical synaptic transmission require the synaptic hub protein Munc13. This essential protein has also been implicated in mediating several forms of use-dependent plasticity, but the mechanisms by which it controls vesicle fusion and plasticity are not well understood. Using the C. elegans Munc13 ortholog UNC-13, we show that deletion of the C2B domain, the most highly conserved domain of Munc13, enhances calcium-dependent exocytosis downstream of vesicle priming, revealing a novel autoinhibitory role for the C2B. Furthermore, C2B inhibition is relieved by calcium binding to C2B, while the neighboring C1 domain acts together with C2B to stabilize the autoinhibited state. Selective disruption of Munc13 autoinhibition profoundly impacts nervous system function in vivo. Thus, C1-C2B exerts a basal inhibition on Munc13 in the primed state, permitting calcium- and lipid-dependent control of C1-C2B to modulate synaptic strength.
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Affiliation(s)
- Francesco Michelassi
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), University of Queensland, Brisbane, 4072 QLD, Australia
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research (CJCADR), University of Queensland, Brisbane, 4072 QLD, Australia
| | - Jeremy S Dittman
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA.
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45
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The potential role of in silico approaches to identify novel bioactive molecules from natural resources. Future Med Chem 2017; 9:1665-1686. [PMID: 28841048 DOI: 10.4155/fmc-2017-0124] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In recent years, integration of in silico approaches to natural product (NP) research reawakened the declined interest in NP-based drug discovery efforts. In particular, advancements in cheminformatics enabled comparison of NP databases with contemporary small-molecule libraries in terms of molecular properties and chemical space localizations. Virtual screening and target fishing approaches were successful in recognizing the untold macromolecular targets for NPs to exploit the unmet therapeutic needs. Developments in molecular docking and scoring methods along with molecular dynamics enabled to predict the target-ligand interactions more accurately taking into consideration the remarkable structural complexity of NPs. Hence, innovative in silico strategies have contributed valuably to the NP research in drug discovery processes as reviewed herein. [Formula: see text].
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46
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Brutkiewicz RR. Cell Signaling Pathways That Regulate Antigen Presentation. THE JOURNAL OF IMMUNOLOGY 2017; 197:2971-2979. [PMID: 27824592 DOI: 10.4049/jimmunol.1600460] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/08/2016] [Indexed: 12/11/2022]
Abstract
Cell signaling pathways regulate much in the life of a cell: from shuttling cargo through intracellular compartments and onto the cell surface, how it should respond to stress, protecting itself from harm (environmental insults or infections), to ultimately, death by apoptosis. These signaling pathways are important for various aspects of the immune response as well. However, not much is known in terms of the participation of cell signaling pathways in Ag presentation, a necessary first step in the activation of innate and adaptive T cells. In this brief review, I discuss the known signaling molecules (and pathways) that regulate how Ags are presented to T cells and the mechanism(s), if identified. Studies in this area have important implications in vaccine development and new treatment paradigms against infectious diseases, autoimmunity, and cancer.
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Affiliation(s)
- Randy R Brutkiewicz
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
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47
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Morales KA, Yang Y, Cole TR, Igumenova TI. Dynamic Response of the C2 Domain of Protein Kinase Cα to Ca 2+ Binding. Biophys J 2017; 111:1655-1667. [PMID: 27760353 DOI: 10.1016/j.bpj.2016.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/04/2016] [Accepted: 09/07/2016] [Indexed: 11/28/2022] Open
Abstract
Ca2+-dependent conserved-region 2 (C2) domains target their host signaling proteins to anionic membranes. The Ca2+-binding event is a prerequisite for membrane association. Here, we investigate multiscale metal-ion-dependent dynamics of the C2 domain of protein kinase Cα (C2α) using NMR spectroscopy. Interactions with metal ions attenuate microsecond-timescale motions of the loop regions, indicating that preorganization of the metal-binding loops occurs before membrane insertion. Binding of a full complement of Ca2+ ions has a profound effect on the millisecond-timescale dynamics of the N- and C-terminal regions of C2α. We propose that Ca2+ binding allosterically destabilizes the terminal regions of C2α and thereby facilitates the conformational rearrangement necessary for full membrane insertion and activation of protein kinase Cα.
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Affiliation(s)
- Krystal A Morales
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Yuan Yang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Taylor R Cole
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
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48
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PKC-δ isoform plays a crucial role in Tat-TLR4 signalling pathway to activate NF-κB and CXCL8 production. Sci Rep 2017; 7:2384. [PMID: 28539656 PMCID: PMC5443767 DOI: 10.1038/s41598-017-02468-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 04/11/2017] [Indexed: 12/20/2022] Open
Abstract
HIV-1 Tat protein induces the production of CXCL8 chemokine in a TLR4/MD2 and PKC dependent manner. The objective of this study was to understand whether these two pathways were distinct or constituted a single common pathway, and to determine the nature of the PKC isoforms involved and their interrelation with the activation of NF-κB and CXCL8 gene product expression. Here, we show that Tat-induced CXCL8 production is essentially dependent on the activation of PKC delta isoform, as shown a) by the capacity of PKC delta dominant negative (DN), and Rottlerin, a selective PKC delta pharmacological inhibitor, to inhibit Tat-induced CXCL8 production and b) by the ability of the constitutively active (CAT) isoform of PKC delta to induce CXCL8 production in a HEK cell line in the absence of Tat stimulation. The finding that comparable amounts of CXCL8 were produced following stimulation with either Tat protein, PKC-delta CAT transfection, or both, argue for the implication of one common pathway where PKC delta is activated downstream of TLR4 recruitment and leads to the activation of NF-κB. Altogether, our results underline the crucial role of PKC delta isoform in activating gene expression of CXCL8, a cytokine largely implicated in the physiopathology of HIV-1 infection.
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Identification of Cav2-PKCβ and Cav2-NOS1 complexes as entities for ultrafast electrochemical coupling. Proc Natl Acad Sci U S A 2017; 114:5707-5712. [PMID: 28507132 DOI: 10.1073/pnas.1616394114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Voltage-activated calcium (Cav) channels couple intracellular signaling pathways to membrane potential by providing Ca2+ ions as second messengers at sufficiently high concentrations to modulate effector proteins located in the intimate vicinity of those channels. Here we show that protein kinase Cβ (PKCβ) and brain nitric oxide synthase (NOS1), both identified by proteomic analysis as constituents of the protein nano-environment of Cav2 channels in the brain, directly coassemble with Cav2.2 channels upon heterologous coexpression. Within Cav2.2-PKCβ and Cav2.2-NOS1 complexes voltage-triggered Ca2+ influx through the Cav channels reliably initiates enzymatic activity within milliseconds. Using BKCa channels as target sensors for nitric oxide and protein phosphorylation together with high concentrations of Ca2+ buffers showed that the complex-mediated Ca2+ signaling occurs in local signaling domains at the plasma membrane. Our results establish Cav2-enzyme complexes as molecular entities for fast electrochemical coupling that reliably convert brief membrane depolarization into precisely timed intracellular signaling events in the mammalian brain.
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Molecular dynamics simulations reveal ligand-controlled positioning of a peripheral protein complex in membranes. Nat Commun 2017; 8:6. [PMID: 28232750 PMCID: PMC5431895 DOI: 10.1038/s41467-016-0015-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 11/17/2016] [Indexed: 01/13/2023] Open
Abstract
Bryostatin is in clinical trials for Alzheimer’s disease, cancer, and HIV/AIDS eradication. It binds to protein kinase C competitively with diacylglycerol, the endogenous protein kinase C regulator, and plant-derived phorbol esters, but each ligand induces different activities. Determination of the structural origin for these differing activities by X-ray analysis has not succeeded due to difficulties in co-crystallizing protein kinase C with relevant ligands. More importantly, static, crystal-lattice bound complexes do not address the influence of the membrane on the structure and dynamics of membrane-associated proteins. To address this general problem, we performed long-timescale (400–500 µs aggregate) all-atom molecular dynamics simulations of protein kinase C–ligand–membrane complexes and observed that different protein kinase C activators differentially position the complex in the membrane due in part to their differing interactions with waters at the membrane inner leaf. These new findings enable new strategies for the design of simpler, more effective protein kinase C analogs and could also prove relevant to other peripheral protein complexes. Natural supplies of bryostatin, a compound in clinical trials for Alzheimer’s disease, cancer, and HIV, are scarce. Here, the authors perform molecular dynamics simulations to understand how bryostatin interacts with membrane-bound protein kinase C, offering insights for the design of bryostatin analogs.
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