1
|
Hendricks EL, Liebl FLW. The CHD family chromatin remodeling enzyme, Kismet, promotes both clathrin-mediated and activity-dependent bulk endocytosis. PLoS One 2024; 19:e0300255. [PMID: 38512854 PMCID: PMC10956772 DOI: 10.1371/journal.pone.0300255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 02/23/2024] [Indexed: 03/23/2024] Open
Abstract
Chromodomain helicase DNA binding domain (CHD) proteins, including CHD7 and CHD8, remodel chromatin to enable transcriptional programs. Both proteins are important for proper neural development as heterozygous mutations in Chd7 and Chd8 are causative for CHARGE syndrome and correlated with autism spectrum disorders, respectively. Their roles in mature neurons are poorly understood despite influencing the expression of genes required for cell adhesion, neurotransmission, and synaptic plasticity. The Drosophila homolog of CHD7 and CHD8, Kismet (Kis), promotes neurotransmission, endocytosis, and larval locomotion. Endocytosis is essential in neurons for replenishing synaptic vesicles, maintaining protein localization, and preserving the size and composition of the presynaptic membrane. Several forms of endocytosis have been identified including clathrin-mediated endocytosis, which is coupled with neural activity and is the most prevalent form of synaptic endocytosis, and activity-dependent bulk endocytosis, which occurs during periods of intense stimulation. Kis modulates the expression of gene products involved in endocytosis including promoting shaggy/GSK3β expression while restricting PI3K92E. kis mutants electrophysiologically phenocopy a liquid facets mutant in response to paradigms that induce clathrin-mediated endocytosis and activity-dependent bulk endocytosis. Further, kis mutants do not show further reductions in endocytosis when activity-dependent bulk endocytosis or clathrin-mediated endocytosis are pharmacologically inhibited. We find that Kis is important in postsynaptic muscle for proper endocytosis but the ATPase domain of Kis is dispensable for endocytosis. Collectively, our data indicate that Kis promotes both clathrin-mediated endocytosis and activity-dependent bulk endocytosis possibly by promoting transcription of several endocytic genes and maintaining the size of the synaptic vesicle pool.
Collapse
Affiliation(s)
- Emily L. Hendricks
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Faith L. W. Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| |
Collapse
|
2
|
Du J, Li SK, Guan LY, Guo Z, Yin JF, Gao L, Kawanishi T, Shimada A, Zhang QP, Zheng LS, Liu YY, Feng XQ, Zhao L, Chen DY, Takeda H, Fan YB. Mechanically sensitive HSF1 is a key regulator of left-right symmetry breaking in zebrafish embryos. iScience 2023; 26:107864. [PMID: 37766982 PMCID: PMC10520531 DOI: 10.1016/j.isci.2023.107864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/08/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
The left-right symmetry breaking of vertebrate embryos requires nodal flow. However, the molecular mechanisms that mediate the asymmetric gene expression regulation under nodal flow remain elusive. Here, we report that heat shock factor 1 (HSF1) is asymmetrically activated in the Kupffer's vesicle of zebrafish embryos in the presence of nodal flow. Deficiency in HSF1 expression caused a significant situs inversus and disrupted gene expression asymmetry of nodal signaling proteins in zebrafish embryos. Further studies demonstrated that HSF1 is a mechanosensitive protein. The mechanical sensation ability of HSF1 is conserved in a variety of mechanical stimuli in different cell types. Moreover, cilia and Ca2+-Akt signaling axis are essential for the activation of HSF1 under mechanical stress in vitro and in vivo. Considering the conserved expression of HSF1 in organisms, these findings unveil a fundamental mechanism of gene expression regulation by mechanical clues during embryonic development and other physiological and pathological transformations.
Collapse
Affiliation(s)
- Jing Du
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
- Institute of Biomechanics and Medical Engineering, Department of Mechanical Engineering, School of Aerospace, Tsinghua University, Beijing 100084, China
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Shu-Kai Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Liu-Yuan Guan
- Institute of Biomechanics and Medical Engineering, Department of Mechanical Engineering, School of Aerospace, Tsinghua University, Beijing 100084, China
| | - Zheng Guo
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Jiang-Fan Yin
- College of life science, Hebei Normal University, Shijiazhuang 050024, China
| | - Li Gao
- College of life science, Hebei Normal University, Shijiazhuang 050024, China
| | - Toru Kawanishi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Atsuko Shimada
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Qiu-Ping Zhang
- Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Department of Histology and Embryology, School of Medicine, Nankai University, Tianjin 300071, China
| | - Li-Sha Zheng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Yi-Yao Liu
- Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Mechanical Engineering, School of Aerospace, Tsinghua University, Beijing 100084, China
| | - Lin Zhao
- Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Department of Histology and Embryology, School of Medicine, Nankai University, Tianjin 300071, China
| | - Dong-Yan Chen
- Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation, Department of Histology and Embryology, School of Medicine, Nankai University, Tianjin 300071, China
| | - Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Yu-Bo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| |
Collapse
|
3
|
Lan Y, Zeng W, Wang Y, Dong X, Shen X, Gu Y, Zhang W, Lu H. Opsin 3 mediates UVA-induced keratinocyte supranuclear melanin cap formation. Commun Biol 2023; 6:238. [PMID: 36869204 PMCID: PMC9984416 DOI: 10.1038/s42003-023-04621-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 02/22/2023] [Indexed: 03/05/2023] Open
Abstract
Solar ultraviolet (UV) radiation-induced DNA damage is a major risk factor for skin cancer development. UV-induced redistribution of melanin near keratinocyte nuclei leads to the formation of a supranuclear cap, which acts as a natural sunscreen and protects DNA by absorbing and scattering UV radiation. However, the mechanism underlying the intracellular movement of melanin in nuclear capping is poorly understood. In this study, we found that OPN3 is an important photoreceptor in human epidermal keratinocytes and is critical for UVA-mediated supranuclear cap formation. OPN3 mediates supranuclear cap formation via the calcium-dependent G protein-coupled receptor signaling pathway and ultimately upregulates Dync1i1 and DCTN1 expression in human epidermal keratinocytes via activating calcium/CaMKII, CREB, and Akt signal transduction. Together, these results clarify the role of OPN3 in regulating melanin cap formation in human epidermal keratinocytes, greatly expanding our understanding of the phototransduction mechanisms involved in physiological function in skin keratinocytes.
Collapse
Affiliation(s)
- Yinghua Lan
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Wen Zeng
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Yu Wang
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Xian Dong
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Xiaoping Shen
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Yangguang Gu
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Wei Zhang
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China
| | - Hongguang Lu
- Department of Dermatology, Affiliated Hospital of Guizhou Medical University, 550001, Guiyang, Guizhou, P.R. China.
| |
Collapse
|
4
|
Mafa-dependent GABAergic activity promotes mouse neonatal apneas. Nat Commun 2022; 13:3284. [PMID: 35672398 PMCID: PMC9174494 DOI: 10.1038/s41467-022-30825-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 05/19/2022] [Indexed: 01/17/2023] Open
Abstract
While apneas are associated with multiple pathological and fatal conditions, the underlying molecular mechanisms remain elusive. We report that a mutated form of the transcription factor Mafa (Mafa4A) that prevents phosphorylation of the Mafa protein leads to an abnormally high incidence of breath holding apneas and death in newborn Mafa4A/4A mutant mice. This apneic breathing is phenocopied by restricting the mutation to central GABAergic inhibitory neurons and by activation of inhibitory Mafa neurons while reversed by inhibiting GABAergic transmission centrally. We find that Mafa activates the Gad2 promoter in vitro and that this activation is enhanced by the mutation that likely results in increased inhibitory drives onto target neurons. We also find that Mafa inhibitory neurons are absent from respiratory, sensory (primary and secondary) and pontine structures but are present in the vicinity of the hypoglossal motor nucleus including premotor neurons that innervate the geniohyoid muscle, to control upper airway patency. Altogether, our data reveal a role for Mafa phosphorylation in regulation of GABAergic drives and suggest a mechanism whereby reduced premotor drives to upper airway muscles may cause apneic breathing at birth. Apneas are associated with many pathological conditions. Here, the authors show in a mouse model that stabilization of the transcription factor Mafa in brainstem GABAergic neurons may contribute to apnea, by decreasing motor drive to muscles controlling the airways.
Collapse
|
5
|
Kuck L, Peart JN, Simmonds MJ. Piezo1 regulates shear-dependent nitric oxide production in human erythrocytes. Am J Physiol Heart Circ Physiol 2022; 323:H24-H37. [PMID: 35559724 DOI: 10.1152/ajpheart.00185.2022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mature circulating red blood cells (RBC) are classically viewed as passive participants in circulatory function, given erythroblasts eject their organelles during maturation. Endogenous production of nitric oxide (NO) and its effects are of particular significance; however, the integration between RBC sensation of the local environment and subsequent activation of mechano-sensitive signaling networks that generate NO remain poorly understood. The present study investigated endogenous NO-production via the RBC-specific nitric oxide synthase-isoform (RBC-NOS), connecting membrane strain with intracellular enzymatic processes. Isolated RBC were obtained from apparently healthy humans. Intracellular NO was compared at rest and following shear (cellular deformation) using semi-quantitative fluorescent imaging. Concurrently, RBC-NOS phosphorylation at its Serine1177 (ser1177) residue was measured. The contribution of cellular deformation to shear-induced NO-production in RBC was determined by rigidifying RBC with the thiol-oxidizing agent diamide; rigid RBC exhibited significantly impaired (up to 80%) capacity to generate NO via RBC-NOS during shear. Standardizing membrane strain of rigid RBC by applying increased shear did not normalize NO-production, or RBC-NOS activation. Calcium-imaging with Fluo-4 revealed that diamide-treated RBC exhibited a 42%-impairment in Piezo1-mediated calcium-movement when compared with untreated RBC. Pharmacological inhibition of Piezo1 with GsMTx4 during shear inhibited RBC-NOS activation in untreated RBC, while Piezo1-activation with Yoda1 in the absence of shear stimulated RBC-NOS activation. Collectively, a novel, mechanically-activated signaling pathway in mature RBC is described. Opening of Piezo1 and subsequent influx of calcium appears to be required for endogenous production of NO in response to mechanical shear, which is accompanied by phosphorylation of RBC-NOS at ser1177.
Collapse
Affiliation(s)
- Lennart Kuck
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Australia
| | - Jason N Peart
- School of Pharmacy and Medical Sciences, Griffith University Gold Coast, Southport, Australia
| | - Michael J Simmonds
- Biorheology Research Laboratory, Menzies Health Institute Queensland, Australia
| |
Collapse
|
6
|
Sakhrani N, Lee AJ, Murphy LA, Kenawy HM, Visco CJ, Ateshian GA, Shah RP, Hung CT. Toward Development of a Diabetic Synovium Culture Model. Front Bioeng Biotechnol 2022; 10:825046. [PMID: 35265601 PMCID: PMC8899218 DOI: 10.3389/fbioe.2022.825046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degradation and inflammation of synovium, the specialized connective tissue that envelops the diarthrodial joint. Type 2 diabetes mellitus (DM) is often found in OA patients, with nearly double the incidence of arthritis reported in patients with diabetes (52%) than those without it (27%). The correlation between OA and DM has been attributed to similar risk factors, namely increasing age and joint loading due to obesity. However, a potential causative link is not well understood due to comorbidities involved with treating diabetic patients, such as high infection rates and poor healing response caused by hyperglycemia and insulin resistance. The purpose of this study was to investigate the effect of hyperglycemic and insulin culture conditions on synovium properties. It was hypothesized that modeling hyperglycemia-induced insulin resistance in synovium would provide novel insights of OA pathogenesis in DM patients. To simulate DM in the synovial joint, healthy synovium was preconditioned in either euglycemic (EG) or hyperglycemic (HG) glucose concentrations with insulin in order to induce the biological response of the diseased phenotype. Synovium biochemical composition was evaluated to determine ECM remodeling under hyperglycemic culture conditions. Concurrent changes in AKT phosphorylation, a signaling pathway implicated in insulin resistance, were measured along with gene expression data for insulin receptors, glucose transporters, and specific glycolysis markers involved in glucose regulation. Since fluid shear stress arising during joint articulation is a relevant upstream stimulus for fibroblast-like synoviocytes (FLS), the predominant cell type in synovium, FLS mechanotransduction was evaluated via intracellular calcium ([Ca2+]i). Incidence and length of primary cilia, a critical effector of cell mechanosensing, were measured as potential mechanisms to support differences in [Ca2+]i responses. Hyperglycemic culture conditions decreased collagen and GAG content compared to EG groups, while insulin recovered ECM constituents. FLS mechanosensitivity was significantly greater in EG and insulin conditions compared to HG and non-insulin treated groups. Hyperglycemic treatment led to decreased incidence and length of primary cilia and decreased AKT phosphorylation, providing possible links to the mechanosensing response and suggesting a potential correlation between glycemic culture conditions, diabetic insulin resistance, and OA development.
Collapse
Affiliation(s)
- Neeraj Sakhrani
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Andy J Lee
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Lance A Murphy
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Hagar M Kenawy
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Christopher J Visco
- Department of Rehabilitation and Regenerative Medicine, Columbia University, New York, NY, United States
| | - Gerard A Ateshian
- Department of Biomedical Engineering, Columbia University, New York, NY, United States.,Department of Mechanical Engineering, Columbia University, New York, NY, United States
| | - Roshan P Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| | - Clark T Hung
- Department of Biomedical Engineering, Columbia University, New York, NY, United States.,Department of Orthopedic Surgery, Columbia University, New York, NY, United States
| |
Collapse
|
7
|
Ivanova D, Cousin MA. Synaptic Vesicle Recycling and the Endolysosomal System: A Reappraisal of Form and Function. Front Synaptic Neurosci 2022; 14:826098. [PMID: 35280702 PMCID: PMC8916035 DOI: 10.3389/fnsyn.2022.826098] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/03/2022] [Indexed: 12/15/2022] Open
Abstract
The endolysosomal system is present in all cell types. Within these cells, it performs a series of essential roles, such as trafficking and sorting of membrane cargo, intracellular signaling, control of metabolism and degradation. A specific compartment within central neurons, called the presynapse, mediates inter-neuronal communication via the fusion of neurotransmitter-containing synaptic vesicles (SVs). The localized recycling of SVs and their organization into functional pools is widely assumed to be a discrete mechanism, that only intersects with the endolysosomal system at specific points. However, evidence is emerging that molecules essential for endolysosomal function also have key roles within the SV life cycle, suggesting that they form a continuum rather than being isolated processes. In this review, we summarize the evidence for key endolysosomal molecules in SV recycling and propose an alternative model for membrane trafficking at the presynapse. This includes the hypotheses that endolysosomal intermediates represent specific functional SV pools, that sorting of cargo to SVs is mediated via the endolysosomal system and that manipulation of this process can result in both plastic changes to neurotransmitter release and pathophysiology via neurodegeneration.
Collapse
Affiliation(s)
- Daniela Ivanova
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
- *Correspondence: Daniela Ivanova,
| | - Michael A. Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
- Michael A. Cousin,
| |
Collapse
|
8
|
Nadzirin IB, Fortuny-Gomez A, Ngum N, Richards D, Ali S, Searcey M, Fountain SJ. Taspine is a natural product that suppresses P2X4 receptor activity via phosphoinositide 3-kinase inhibition. Br J Pharmacol 2021; 178:4859-4872. [PMID: 34398973 DOI: 10.1111/bph.15663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND & PURPOSE P2X4 is a ligand-gated cation channel activated by extracellular ATP, involved in neuropathic pain, inflammation and arterial tone. EXPERIMENTAL APPROACH Natural products were screened against human or mouse P2X4 activity using fura-2 loaded 1321N1 cells for measurement of intracellular Ca2+ responses; whole-cell currents were measured by patch clamp electrophysiological. Human primary macrophage chemokine release was used to assess effect of taspine on inflammatory cell function. An enzymatic assay was performed to assess the effect of taspine on recombinant PI3-kinase. KEY RESULTS A natural product screen identified taspine as an inhibitor of human P2X4 activity. Taspine inhibits human and mouse P2X4-mediated Ca2+ influx in 1321N1 cells expressing receptors (IC50 1.6±0.4 μM and 1.6±0.3 μM, respectively), but lacked activity at human P2X2, P2X3, P2X2/3 and P2X7 receptors. Taspine inhibited the maximal response at human and mouse P2X4 but had no effect on ATP potency. Taspine has a slow onset rate (~15 mins for half-maximal inhibition), irreversible over 30 minutes of washout. Taspine inhibits P2X4-mediated Ca2+ signalling in mouse BV-2 microglia cells and human primary macrophage. Taspine inhibited P2X4-mediated CXCL5 secretion in human primary macrophage. Taspine reversed ivermectin-induced potentiation of P2X4 currents in 1321N1 stably expressing cells. The known PI3-kinase inhibitor LY294002 mimicked the properties of taspine on P2X4-mediated Ca2+ influx and whole-cell currents. Taspine directly inhibited the enzymatic activity of recombinant PI3-kinase in a competitive manner. CONCLUSIONS AND IMPLICATIONS Taspine is a novel natural product P2X4 inhibitor, mediating its effect through PI3-kinase inhibitor rather than receptor antagonism. Taspine can inhibit the pro-inflammatory signalling by P2X4 in human primary macrophage.
Collapse
Affiliation(s)
- Izzuddin Bin Nadzirin
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park.,Kulliyyah of Allied Health Sciences, International Islamic University Malaysia, Kuantan Campus, Kuantan, Malaysia
| | - Anna Fortuny-Gomez
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park
| | - Neville Ngum
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park
| | - David Richards
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park
| | - Seema Ali
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park
| | - Mark Searcey
- School of Pharmacy, University of East Anglia, Norwich Research Park
| | - Samuel J Fountain
- Biomedical Research Centre, School of Biological Sciences, University of East Anglia, Norwich Research Park
| |
Collapse
|
9
|
Chiou JT, Shi YJ, Lee YC, Wang LJ, Chen YJ, Chang LS. Carboxyl group-modified α-lactalbumin induces TNF-α-mediated apoptosis in leukemia and breast cancer cells through the NOX4/p38 MAPK/PP2A axis. Int J Biol Macromol 2021; 187:513-527. [PMID: 34310992 DOI: 10.1016/j.ijbiomac.2021.07.133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 12/30/2022]
Abstract
To clarify the mechanism of semicarbazide-modified α-lactalbumin (SEM-LA)-mediated cytotoxicity, we investigated its effect on human U937 leukemia cells and MCF-7 breast cancer cells in the current study. SEM-LA induced apoptosis in U937 cells, which showed increased NOX4 expression, procaspase-8 degradation, and t-Bid production. FADD depletion inhibited SEM-LA-elicited caspase-8 activation, t-Bid production, and cell death, indicating that SEM-LA activated death receptor-mediated apoptosis in U937 cells. SEM-LA stimulated Ca2+-mediated Akt activation, which in turn increased Sp1- and p300-mediated NOX4 transcription. The upregulation of NOX4 expression promoted ROS-mediated p38 MAPK phosphorylation, leading to protein phosphatase 2A (PP2A)-regulated tristetraprolin (TTP) degradation. Remarkably, TTP downregulation increased the stability of TNF-α mRNA, resulting in the upregulation of TNF-α protein expression. Abolishment of Ca2+-NOX4-ROS axis-mediated p38 MAPK activation attenuated SEM-LA-induced TNF-α upregulation and protected U937 cells from SEM-LA-mediated cytotoxicity. The restoration of TTP expression alleviated the effect of TNF-α upregulation and cell death induced by SEM-LA. Altogether, the data in this study demonstrate that SEM-LA activates TNF-α-mediated apoptosis in U937 cells through the NOX4/p38 MAPK/PP2A axis. We think that a similar pathway can also explain the death of MCF-7 human breast cancer cells after SEM-LA treatment.
Collapse
Affiliation(s)
- Jing-Ting Chiou
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Yi-Jun Shi
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Yuan-Chin Lee
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Liang-Jun Wang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Ying-Jung Chen
- Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Long-Sen Chang
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; Department of Biotechnology, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| |
Collapse
|
10
|
Morgan AJ, Davis LC, Galione A. Choreographing endo-lysosomal Ca 2+ throughout the life of a phagosome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119040. [PMID: 33872669 DOI: 10.1016/j.bbamcr.2021.119040] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 12/20/2022]
Abstract
The emergence of endo-lysosomes as ubiquitous Ca2+ stores with their unique cohort of channels has resulted in their being implicated in a growing number of processes in an ever-increasing number of cell types. The architectural and regulatory constraints of these acidic Ca2+ stores distinguishes them from other larger Ca2+ sources such as the ER and influx across the plasma membrane. In view of recent advances in the understanding of the modes of operation, we discuss phagocytosis as a template for how endo-lysosomal Ca2+ signals (generated via TPC and TRPML channels) can be integrated in multiple sophisticated ways into biological processes. Phagocytosis illustrates how different endo-lysosomal Ca2+ signals drive different phases of a process, and how these can be altered by disease or infection.
Collapse
Affiliation(s)
- Anthony J Morgan
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK.
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Park, Oxford OX1 3QT, UK.
| |
Collapse
|
11
|
Tammineni ER, Kraeva N, Figueroa L, Manno C, Ibarra CA, Klip A, Riazi S, Rios E. Intracellular calcium leak lowers glucose storage in human muscle, promoting hyperglycemia and diabetes. eLife 2020; 9:53999. [PMID: 32364497 PMCID: PMC7282812 DOI: 10.7554/elife.53999] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/04/2020] [Indexed: 12/18/2022] Open
Abstract
Most glucose is processed in muscle, for energy or glycogen stores. Malignant Hyperthermia Susceptibility (MHS) exemplifies muscle conditions that increase [Ca2+]cytosol. 42% of MHS patients have hyperglycemia. We show that phosphorylated glycogen phosphorylase (GPa), glycogen synthase (GSa) – respectively activated and inactivated by phosphorylation – and their Ca2+-dependent kinase (PhK), are elevated in microsomal extracts from MHS patients’ muscle. Glycogen and glucose transporter GLUT4 are decreased. [Ca2+]cytosol, increased to MHS levels, promoted GP phosphorylation. Imaging at ~100 nm resolution located GPa at sarcoplasmic reticulum (SR) junctional cisternae, and apo-GP at Z disk. MHS muscle therefore has a wide-ranging alteration in glucose metabolism: high [Ca2+]cytosol activates PhK, which inhibits GS, activates GP and moves it toward the SR, favoring glycogenolysis. The alterations probably cause these patients’ hyperglycemia. For basic studies, MHS emerges as a variable stressor, which forces glucose pathways from the normal to the diseased range, thereby exposing novel metabolic links. Animals and humans move by contracting the skeletal muscles attached to their bones. These muscles take up a type of sugar called glucose from food and use it to fuel contractions or store it for later in the form of glycogen. If muscles fail to use glucose it can lead to excessive sugar levels in the blood and a condition called diabetes. Within muscle cells are stores of calcium that signal the muscle to contract. Changes in calcium levels enhance the uptake of glucose that fuel these contractions. However, variations in calcium have also been linked to diabetes, and it remained unclear when and how these ‘signals’ become harmful. People with a condition called malignant hyperthermia susceptibility (MHS for short) have genetic mutations that allow calcium to leak out from these stores. This condition may result in excessive contractions causing the muscle to over-heat, become rigid and break down, which can lead to death if left untreated. A clinical study in 2019 found that out of hundreds of patients who had MHS, nearly half had high blood sugar and were likely to develop diabetes. Now, Tammineni et al. – including some of the researchers involved in the 2019 study – have set out to find why calcium leaks lead to elevated blood sugar levels. The experiments showed that enzymes that help convert glycogen to glucose are more active in patients with MHS, and found in different locations inside muscle cells. Whereas the enzymes that change glucose into glycogen are less active. This slows down the conversion of glucose into glycogen for storage and speeds up the breakdown of glycogen into glucose. Patients with MHS also had fewer molecules that transport glucose into muscle cells and stored less glycogen. These changes imply that less glucose is being removed from the blood. Next, Tammineni et al. used a microscopy technique that is able to distinguish finely separated objects with a precision not reached before in living muscle. This revealed that when the activity of the enzyme that breaks down glycogen increased, it moved next to the calcium store. This effect was also observed in the muscle cells of MHS patients that leaked calcium from their stores. Taken together, these observations may explain why patients with MHS have high levels of sugar in their blood. These findings suggest that MHS may start decades before developing diabetes and blood sugar levels in these patients should be regularly monitored. Future studies should investigate whether drugs that block calcium from leaking may help prevent high blood sugar in patients with MHS or other conditions that cause a similar calcium leak.
Collapse
Affiliation(s)
- Eshwar R Tammineni
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, United States
| | - Natalia Kraeva
- Malignant Hyperthermia Investigation Unit (MHIU) of the University Health Network (Canada), Toronto, Canada.,Department of Anaesthesia & Pain Management, Toronto General Hospital, UHN, University of Toronto, Toronto, Canada
| | - Lourdes Figueroa
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, United States
| | - Carlo Manno
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, United States
| | - Carlos A Ibarra
- Malignant Hyperthermia Investigation Unit (MHIU) of the University Health Network (Canada), Toronto, Canada.,Department of Anaesthesia & Pain Management, Toronto General Hospital, UHN, University of Toronto, Toronto, Canada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit (MHIU) of the University Health Network (Canada), Toronto, Canada.,Department of Anaesthesia & Pain Management, Toronto General Hospital, UHN, University of Toronto, Toronto, Canada
| | - Eduardo Rios
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, United States
| |
Collapse
|
12
|
Abstract
In spite of the high metabolic cost of cellular production, the brain contains only a fraction of the neurons generated during embryonic development. In the rodent cerebral cortex, a first wave of programmed cell death surges at embryonic stages and affects primarily progenitor cells. A second, larger wave unfolds during early postnatal development and ultimately determines the final number of cortical neurons. Programmed cell death in the developing cortex is particularly dependent on neuronal activity and unfolds in a cell-specific manner with precise temporal control. Pyramidal cells and interneurons adjust their numbers in sync, which is likely crucial for the establishment of balanced networks of excitatory and inhibitory neurons. In contrast, several other neuronal populations are almost completely eliminated through apoptosis during the first two weeks of postnatal development, highlighting the importance of programmed cell death in sculpting the mature cerebral cortex.
Collapse
Affiliation(s)
- Fong Kuan Wong
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, United Kingdom; .,MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom
| | - Oscar Marín
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London SE1 1UL, United Kingdom; .,MRC Centre for Neurodevelopmental Disorders, King's College London, London SE1 1UL, United Kingdom
| |
Collapse
|
13
|
Activity-dependent bulk endocytosis proteome reveals a key presynaptic role for the monomeric GTPase Rab11. Proc Natl Acad Sci U S A 2018; 115:E10177-E10186. [PMID: 30301801 PMCID: PMC6205440 DOI: 10.1073/pnas.1809189115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The maintenance of neurotransmission by synaptic vesicle (SV) recycling is critical to brain function. The dominant SV recycling mode during intense activity is activity-dependent bulk endocytosis (ADBE), suggesting it will perform a pivotal role in neurotransmission. However, the role of ADBE is still undetermined, due to the absence of identified molecules specific for this process. The determination of the bulk endosome proteome (a key ADBE organelle) revealed that it has a unique molecular signature and identified a role for Rab11 in presynaptic function. This work provides the molecular inventory of ADBE, a resource that will be of significant value to researchers wishing to modulate neurotransmission during intense neuronal activity in both health and disease. Activity-dependent bulk endocytosis (ADBE) is the dominant mode of synaptic vesicle endocytosis during high-frequency stimulation, suggesting it should play key roles in neurotransmission during periods of intense neuronal activity. However, efforts in elucidating the physiological role of ADBE have been hampered by the lack of identified molecules which are unique to this endocytosis mode. To address this, we performed proteomic analysis on purified bulk endosomes, which are a key organelle in ADBE. Bulk endosomes were enriched via two independent approaches, a classical subcellular fractionation method and isolation via magnetic nanoparticles. There was a 77% overlap in proteins identified via the two protocols, and these molecules formed the ADBE core proteome. Bioinformatic analysis revealed a strong enrichment in cell adhesion and cytoskeletal and signaling molecules, in addition to expected synaptic and trafficking proteins. Network analysis identified Rab GTPases as a central hub within the ADBE proteome. Subsequent investigation of a subset of these Rabs revealed that Rab11 both facilitated ADBE and accelerated clathrin-mediated endocytosis. These findings suggest that the ADBE proteome will provide a rich resource for the future study of presynaptic function, and identify Rab11 as a regulator of presynaptic function.
Collapse
|
14
|
Zhang M, Wu Y, Xie L, Teng CH, Wu FF, Xu KB, Chen X, Xiao J, Zhang HY, Chen DQ. Isoliquiritigenin protects against blood‑brain barrier damage and inhibits the secretion of pro-inflammatory cytokines in mice after traumatic brain injury. Int Immunopharmacol 2018; 65:64-75. [PMID: 30290368 DOI: 10.1016/j.intimp.2018.09.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/23/2018] [Accepted: 09/27/2018] [Indexed: 12/15/2022]
Abstract
Traumatic brain injury (TBI) caused by an external mechanical force acting on the brain is a serious neurological condition. Inflammation plays an important role in prolonging secondary tissue injury after TBI, leading to neuronal cell death and dysfunction. Isoliquiritigenin (ILG) is a flavonoid monomer with anti-inflammatory characteristic. Thus, we had investigated the potential protective effects of ILG on TBI-induced injuries and identified the mechanisms underlying it. Here, we have demonstrated that ILG preserves blood brain barrier (BBB) integrity in vivo, suppresses the activation of microglia and inflammatory responses in mice after TBI, consequently leading to neurofunctional deficits, brain oedema, structural damage, and macrophage infiltration. In vitro, ILG exerts anti-inflammatory effect, and upregulates tight junction proteins 120‑β‑catenin and occludin in SH‑SY5Y cells under oxygen glucose deprivation/reoxygenation (OGD/D) condition. Additionally, we found that PI3K/AKT/GSK‑3β signalling pathway is involved in ILG treatment for TBI. To further confirm it, we had used SC79 (ethyl 2‑amino‑6‑chloro‑4‑(1‑cyano‑2‑ethoxy‑2‑oxoethyl)‑4H‑chromene‑3‑carboxylate), an Akt specific activator, to activate Akt, we found that SC79 partially reduces the protective effect of ILG for TBI. Overall, our current study reveals the neuroprotective role of ILG on TBI-induced BBB damage, downregulated tight junction proteins via PI3K/AKT/GSK‑3β signalling pathway. Furthermore, ILG suppresses the secretion of pro-inflammatory cytokines after TBI through inhibiting the PI3K/AKT/GSK‑3β/NF‑κB signalling pathway. Our findings suggest that GSK‑3β is a key regulatory factor during TBI-induced secretion of inflammatory cytokines, neuronal apoptosis and destruction of BBB.
Collapse
Affiliation(s)
- Man Zhang
- Department of Emergency, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yanqing Wu
- Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China; The Institute of Life Sciences, Wenzhou University, Wenzhou, Zhejiang 325035, China
| | - Ling Xie
- Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Chen-Huai Teng
- Department of Emergency, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Fang-Fang Wu
- Department of Emergency, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Ke-Bin Xu
- Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiong Chen
- Department of Endocrinology, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jian Xiao
- Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Hong-Yu Zhang
- Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| | - Da-Qing Chen
- Department of Emergency, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou Medical University, Wenzhou, Zhejiang, China.
| |
Collapse
|
15
|
Bhattacharya A, Kumar J, Hermanson K, Sun Y, Qureshi H, Perley D, Scheidegger A, Singh BB, Dhasarathy A. The calcium channel proteins ORAI3 and STIM1 mediate TGF-β induced Snai1 expression. Oncotarget 2018; 9:29468-29483. [PMID: 30034631 PMCID: PMC6047677 DOI: 10.18632/oncotarget.25672] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/09/2018] [Indexed: 12/11/2022] Open
Abstract
Calcium influx into cells via plasma membrane protein channels is tightly regulated to maintain cellular homeostasis. Calcium channel proteins in the plasma membrane and endoplasmic reticulum have been linked to cancer, specifically during the epithelial-mesenchymal transition (EMT), a cell state transition process implicated in both cancer cell migration and drug resistance. The transcription factor SNAI1 (SNAIL) is upregulated during EMT and is responsible for gene expression changes associated with EMT, but the calcium channels required for Snai1 expression remain unknown. In this study, we show that blocking store-operated calcium entry (SOCE) with 2-aminoethoxydiphenylborane (2APB) reduces cell migration but, paradoxically, increases the level of TGF-β dependent Snai1 gene activation. We determined that this increased Snai1 transcription involves signaling through the AKT pathway and subsequent binding of NF-κB (p65) at the Snai1 promoter in response to TGF-β. We also demonstrated that the calcium channel protein ORAI3 and the stromal interaction molecule 1 (STIM1) are required for TGF-β dependent Snai1 transcription. These results suggest that calcium channels differentially regulate cell migration and Snai1 transcription, indicating that each of these steps could be targeted to ensure complete blockade of cancer progression.
Collapse
Affiliation(s)
- Atrayee Bhattacharya
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Janani Kumar
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
- Present address: MD Anderson Cancer Center, Mitchell Basic Sciences Research Building, TX, USA
| | - Kole Hermanson
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Yuyang Sun
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
- Present address: UT Health Science Center, San Antonio, San Antonio, TX, USA
| | - Humaira Qureshi
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
- Present address: Habib University, University Avenue, Gulistan-e-Jauhar, Karachi, Pakistan
| | - Danielle Perley
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Adam Scheidegger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Brij B. Singh
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
- Present address: UT Health Science Center, San Antonio, San Antonio, TX, USA
| | - Archana Dhasarathy
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| |
Collapse
|
16
|
Vogelaar CF, Mandal S, Lerch S, Birkner K, Birkenstock J, Bühler U, Schnatz A, Raine CS, Bittner S, Vogt J, Kipnis J, Nitsch R, Zipp F. Fast direct neuronal signaling via the IL-4 receptor as therapeutic target in neuroinflammation. Sci Transl Med 2018; 10:10/430/eaao2304. [DOI: 10.1126/scitranslmed.aao2304] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 12/11/2017] [Accepted: 01/26/2018] [Indexed: 12/13/2022]
|
17
|
Hurtado E, Cilleros V, Just L, Simó A, Nadal L, Tomàs M, Garcia N, Lanuza MA, Tomàs J. Synaptic Activity and Muscle Contraction Increases PDK1 and PKCβI Phosphorylation in the Presynaptic Membrane of the Neuromuscular Junction. Front Mol Neurosci 2017; 10:270. [PMID: 28890686 PMCID: PMC5574929 DOI: 10.3389/fnmol.2017.00270] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/11/2017] [Indexed: 12/20/2022] Open
Abstract
Conventional protein kinase C βI (cPKCβI) is a conventional protein kinase C (PKC) isoform directly involved in the regulation of neurotransmitter release in the neuromuscular junction (NMJ). It is located exclusively at the nerve terminal and both synaptic activity and muscle contraction modulate its protein levels and phosphorylation. cPKCβI molecular maturation includes a series of phosphorylation steps, the first of which is mediated by phosphoinositide-dependent kinase 1 (PDK1). Here, we sought to localize PDK1 in the NMJ and investigate the hypothesis that synaptic activity and muscle contraction regulate in parallel PDK1 and cPKCβI phosphorylation in the membrane fraction. To differentiate the presynaptic and postsynaptic activities, we abolished muscle contraction with μ-conotoxin GIIIB (μ-CgTx-GIIIB) in some experiments before stimulation of the phrenic nerve (1 Hz, 30 min). Then, we analyzed total and membrane/cytosol fractions of skeletal muscle by Western blotting. Results showed that PDK1 is located exclusively in the nerve terminal of the NMJ. After nerve stimulation with and without coincident muscle contraction, total PDK1 and phosphorylated PDK1 (pPDK1) protein levels remained unaltered. However, synaptic activity specifically enhanced phosphorylation of PDK1 in the membrane, an important subcellular location for PDK1 function. This increase in pPDK1 coincides with a significant increase in the phosphorylation of its substrate cPKCβI also in the membrane fraction. Moreover, muscle contraction maintains PDK1 and pPDK1 but increases cPKCβI protein levels and its phosphorylation. Thus, even though PDK1 activity is maintained, pcPKCβI levels increase in concordance with total cPKCβI. Together, these results indicate that neuromuscular activity could induce the membrane targeting of pPDK1 in the nerve terminal of the NMJ to promote the phosphorylation of the cPKCβI, which is involved in ACh release.
Collapse
Affiliation(s)
- Erica Hurtado
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Víctor Cilleros
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Laia Just
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Anna Simó
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Laura Nadal
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Marta Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Neus Garcia
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Maria A Lanuza
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| | - Josep Tomàs
- Unitat d'Histologia i Neurobiologia (UHNEUROB), Facultat de Medicina i Ciències de la Salut, Universitat Rovira i VirgiliReus, Spain
| |
Collapse
|
18
|
Díaz-García CM, Mongeon R, Lahmann C, Koveal D, Zucker H, Yellen G. Neuronal Stimulation Triggers Neuronal Glycolysis and Not Lactate Uptake. Cell Metab 2017; 26:361-374.e4. [PMID: 28768175 PMCID: PMC5559896 DOI: 10.1016/j.cmet.2017.06.021] [Citation(s) in RCA: 288] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 04/29/2017] [Accepted: 06/27/2017] [Indexed: 01/05/2023]
Abstract
Proper brain function requires a substantial energy supply, up to 20% of whole-body energy in humans, and brain activation produces large dynamic variations in energy demand. While local increases in cerebral blood flow are well known, the cellular responses to energy demand are controversial. During brain excitation, glycolysis of glucose to lactate temporarily exceeds the rate of mitochondrial fuel oxidation; although the increased energy demand occurs mainly within neurons, some have suggested this glycolysis occurs mainly in astrocytes, which then shuttle lactate to neurons as their primary fuel. Using metabolic biosensors in acute hippocampal slices and brains of awake mice, we find that neuronal metabolic responses to stimulation do not depend on astrocytic stimulation by glutamate release, nor do they require neuronal uptake of lactate; instead they reflect increased direct glucose consumption by neurons. Neuronal glycolysis temporarily outstrips oxidative metabolism, and provides a rapid response to increased energy demand.
Collapse
Affiliation(s)
| | - Rebecca Mongeon
- Department of Neurobiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Carolina Lahmann
- Department of Neurobiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Dorothy Koveal
- Department of Neurobiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Hannah Zucker
- Department of Neurobiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Gary Yellen
- Department of Neurobiology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
| |
Collapse
|