1
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Yang BZ, Xiang B, Wang T, Ma S, Li CSR. Neurogenetic underpinnings of nicotine use severity: Integrating the brain transcriptomes and GWAS variants via network approaches. Psychiatry Res 2024; 334:115815. [PMID: 38422867 PMCID: PMC11017751 DOI: 10.1016/j.psychres.2024.115815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
Our study focused on human brain transcriptomes and the genetic risks of cigarettes per day (CPD) to investigate the neurogenetic mechanisms of individual variation in nicotine use severity. We constructed whole-brain and intramodular region-specific coexpression networks using BrainSpan's transcriptomes, and the genomewide association studies identified risk variants of CPD, confirmed the associations between CPD and each gene set in the region-specific subnetworks using an independent dataset, and conducted bioinformatic analyses. Eight brain-region-specific coexpression subnetworks were identified in association with CPD: amygdala, hippocampus, medial prefrontal cortex (MPFC), orbitofrontal cortex (OPFC), dorsolateral prefrontal cortex, striatum, mediodorsal nucleus of the thalamus (MDTHAL), and primary motor cortex (M1C). Each gene set in the eight subnetworks was associated with CPD. We also identified three hub proteins encoded by GRIN2A in the amygdala, PMCA2 in the hippocampus, MPFC, OPFC, striatum, and MDTHAL, and SV2B in M1C. Intriguingly, the pancreatic secretion pathway appeared in all the significant protein interaction subnetworks, suggesting pleiotropic effects between cigarette smoking and pancreatic diseases. The three hub proteins and genes are implicated in stress response, drug memory, calcium homeostasis, and inhibitory control. These findings provide novel evidence of the neurogenetic underpinnings of smoking severity.
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Affiliation(s)
- Bao-Zhu Yang
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Veterans Affairs Connecticut Healthcare System, West Haven, CT, USA.
| | - Bo Xiang
- Department of Psychiatry, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, China.
| | - Tingting Wang
- Department of Psychiatry, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan Province, China
| | - Shuangge Ma
- Department of Biostatistics, Yale University, New Haven, CT, USA
| | - Chiang-Shan R Li
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA; Wu Tsai Institute, Yale University, New Haven, CT, USA
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2
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Yi T, Wagner G. Malignant tumor cells engender second membrane-lined organelles for self-protection and tumor progression. Proc Natl Acad Sci U S A 2024; 121:e2317141121. [PMID: 38294933 PMCID: PMC10861905 DOI: 10.1073/pnas.2317141121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 12/14/2023] [Indexed: 02/02/2024] Open
Abstract
Cancer is a leading cause of mortality in humans, but the efficacy of current treatments for many cancers is limited, as they lack unique mechanistically defined targets. Here, we show that, upon malignant transformation, aggressive oncocells generate a second membrane exterior to their plasma membrane to form cytocapsulas (CCs) and cytocapsular tubes (CCTs), which all together constitute cytocapsular oncocells with pleotropic biological functions in cancer patient tissues in vivo. Proteomic and biochemical analyses revealed that the PMCA2 calcium pump is highly up-regulated in CCs and CCTs in malignant tumors but not in normal tissues, thus identifying a unique cancer biomarker and target for cancer therapy. Cytocapsular oncocells are universally present in solid cancers and appear in hematologic cancers in immune organs. Multi-cell malignant tumors are also enveloped by protective CC membranes. These cytocapsular tumors (CTs) generate numerous CCTs that form freeways for cancer cell metastasis to both neighboring and distant destinations. Entire cytocapsular tumor networks (CTNs) dominate physical cancer metastasis pathways in cancer patients in vivo. Later, CCTs invade micro blood vessels and release cytocapsular oncocells into the blood, providing a source of circulating tumor cells. CTNs interconnect cytocapsular tumors in primary and secondary cancer niches, creating larger cytocapsular tumor network systems (CTNSs). Primary and secondary CTNSs are in turn interconnected, forming dynamic and integrated CTNSs. Thus, interconnected cytocapsular oncocells, CTNs, and CTNSs coordinate cancer progression via the integrated cytocapsular membrane systems.
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Affiliation(s)
- Tingfang Yi
- Cytocapsula Research Institute, Cambridge, MA02142
- Centiver Ltd., Cambridge, MA02142
| | - Gerhard Wagner
- Cytocapsula Research Institute, Cambridge, MA02142
- Centiver Ltd., Cambridge, MA02142
- Department of Biological Chemistry and Molecular Pharmacology of Harvard Medical School, Boston, MA02115
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3
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Jeong J, Lee J, Talaia G, Kim W, Song J, Hong J, Yoo K, Gonzalez DG, Athonvarangkul D, Shin J, Dann P, Haberman AM, Kim LK, Ferguson SM, Choi J, Wysolmerski J. Intracellular calcium links milk stasis to lysosome-dependent cell death during early mammary gland involution. Cell Mol Life Sci 2024; 81:29. [PMID: 38212474 PMCID: PMC10784359 DOI: 10.1007/s00018-023-05044-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 10/17/2023] [Accepted: 11/07/2023] [Indexed: 01/13/2024]
Abstract
Involution of the mammary gland after lactation is a dramatic example of coordinated cell death. Weaning causes distension of the alveolar structures due to the accumulation of milk, which, in turn, activates STAT3 and initiates a caspase-independent but lysosome-dependent cell death (LDCD) pathway. Although the importance of STAT3 and LDCD in early mammary involution is well established, it has not been entirely clear how milk stasis activates STAT3. In this report, we demonstrate that protein levels of the PMCA2 calcium pump are significantly downregulated within 2-4 h of experimental milk stasis. Reductions in PMCA2 expression correlate with an increase in cytoplasmic calcium in vivo as measured by multiphoton intravital imaging of GCaMP6f fluorescence. These events occur concomitant with the appearance of nuclear pSTAT3 expression but prior to significant activation of LDCD or its previously implicated mediators such as LIF, IL6, and TGFβ3, all of which appear to be upregulated by increased intracellular calcium. We further demonstrate that increased intracellular calcium activates STAT3 by inducing degradation of its negative regulator, SOCS3. We also observed that milk stasis, loss of PMCA2 expression and increased intracellular calcium levels activate TFEB, an important regulator of lysosome biogenesis through a process involving inhibition of CDK4/6 and cell cycle progression. In summary, these data suggest that intracellular calcium serves as an important proximal biochemical signal linking milk stasis to STAT3 activation, increased lysosomal biogenesis, and lysosome-mediated cell death.
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Affiliation(s)
- Jaekwang Jeong
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
| | - Jongwon Lee
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - Gabriel Talaia
- Departments of Cell Biology and of Neuroscience, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Wonnam Kim
- Division of Phamacology, School of Korean Medicine, Pusan National University, Yangsan, Gyeongnam, 50612, Republic of Korea
| | - Junho Song
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - Juhyeon Hong
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - Kwangmin Yoo
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - David G Gonzalez
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Diana Athonvarangkul
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Jaehun Shin
- Integrated Science Engineering Division, Underwood International College, Yonsei University, Seoul, Republic of Korea
| | - Pamela Dann
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Ann M Haberman
- Departments of Immunobiology and Laboratory Medicine, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Lark Kyun Kim
- Department of Biomedical Sciences, Graduate School of Medical Science, Brain Korea 21 Project, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, 06230, Republic of Korea
| | - Shawn M Ferguson
- Departments of Cell Biology and of Neuroscience, Wu Tsai Institute, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Jungmin Choi
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
| | - John Wysolmerski
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
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4
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Jeong J, Lee J, Talaia G, Kim W, Song J, Hong J, Yoo K, Gonzalez D, Athonvarangkul D, Shin J, Dann P, Haberman A, Kim LK, Ferguson S, Choi J, Wysolmerski J. Intracellular Calcium links Milk Stasis to Lysosome Dependent Cell Death by Activating a TGFβ3/TFEB/STAT3 Pathway Early during Mammary Gland Involution. Res Sq 2023:rs.3.rs-3030763. [PMID: 37398309 PMCID: PMC10312953 DOI: 10.21203/rs.3.rs-3030763/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Involution of the mammary gland after lactation is a dramatic example of coordinated cell death. Weaning causes distension of the alveolar structures due to the accumulation of milk, which, in turn, activates STAT3 and initiates a caspase-independent but lysosome-dependent cell death (LDCD) pathway. Although the importance of STAT3 and LDCD in early mammary involution is well established, it has not been entirely clear how milk stasis activates STAT3. In this report, we demonstrate that protein levels of the PMCA2 calcium pump are significantly downregulated within 2-4 hours of experimental milk stasis. Reductions in PMCA2 expression correlate with an increase in cytoplasmic calcium in vivo as measured by multiphoton intravital imaging of GCaMP6f fluorescence. These events occur concomitant with the appearance of nuclear pSTAT3 expression but prior to significant activation of LDCD or its previously implicated mediators such as LIF, IL6 and TGFβ3, all of which appear to be upregulated by increased intracellular calcium. We also observed that milk stasis, loss of PMCA2 expression and increased intracellular calcium levels activate TFEB, an important regulator of lysosome biogenesis. This is the result of increased TGFβ signaling and inhibition of cell cycle progression. Finally, we demonstrate that increased intracellular calcium activates STAT3 by inducing degradation of its negative regulator, SOCS3, a process which also appears to be mediated by TGFβ signaling. In summary, these data suggest that intracellular calcium serves as an important proximal biochemical signal linking milk stasis to STAT3 activation, increased lysosomal biogenesis, and lysosome-mediated cell death.
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Affiliation(s)
- Jaekwang Jeong
- Yale School of Medicine: Yale University School of Medicine
| | | | - Gabriel Talaia
- Yale School of Medicine: Yale University School of Medicine
| | | | | | | | | | - David Gonzalez
- Yale School of Medicine: Yale University School of Medicine
| | | | | | - Pamela Dann
- Yale School of Medicine: Yale University School of Medicine
| | - Ann Haberman
- Yale School of Medicine: Yale University School of Medicine
| | | | - Shawn Ferguson
- Yale School of Medicine: Yale University School of Medicine
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5
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Jeong J, Choi J, Kim W, Dann P, Takyar F, Gefter JV, Friedman PA, Wysolmerski JJ. Inhibition of ezrin causes PKCα-mediated internalization of erbb2/HER2 tyrosine kinase in breast cancer cells. J Biol Chem 2018; 294:887-901. [PMID: 30463939 PMCID: PMC6341383 DOI: 10.1074/jbc.ra118.004143] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Unlike other ErbB family members, HER2 levels are maintained on the cell surface when the receptor is activated, allowing prolonged signaling and contributing to its transforming ability. Interactions between HER2, HSP90, PMCA2, and NHERF1 within specialized plasma membrane domains contribute to the membrane retention of HER2. We hypothesized that the scaffolding protein ezrin, which has been shown to interact with NHERF1, might also help stabilize the HER2-PMCA2-NHERF1 complex at the plasma membrane. Therefore, we examined ezrin expression and its relationship with HER2, NHERF1, and PMCA2 levels in murine and human breast cancers. We also used genetic knockdown and/or pharmacologic inhibition of ezrin, HSP90, NHERF1, PMCA2, and HER2 to examine the functional relationships between these factors and membrane retention of HER2. We found ezrin to be expressed at low levels at the apical surface of normal mammary epithelial cells, but its expression is up-regulated and correlates with HER2 expression in hyperplasia and tumors in murine mammary tumor virus-Neu mice, in human HER2-positive breast cancer cell lines, and in ductal carcinoma in situ and invasive breast cancers from human patients. In breast cancer cells, ezrin co-localizes and interacts with HER2, NHERF1, PMCA2, and HSP90 in specialized membrane domains, and inhibiting ezrin disrupts interactions between HER2, PMCA2, NHERF1, and HSP90, inhibiting HER2 signaling and causing PKCα-mediated internalization and degradation of HER2. Inhibition of ezrin synergizes with lapatinib in a PKCα-dependent fashion to inhibit proliferation and promote apoptosis in HER2-positive breast cancer cells. We conclude that ezrin stabilizes a multiprotein complex that maintains active HER2 at the cell surface.
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Affiliation(s)
- Jaekwang Jeong
- From the Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Jungmin Choi
- the Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Wonnam Kim
- From the Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.,the Division of Pharmacology, College of Korean Medicine, Semyung University, Jecheon 27136, Republic of Korea, and
| | - Pamela Dann
- From the Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Farzin Takyar
- From the Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510
| | - Julia V Gefter
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Peter A Friedman
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - John J Wysolmerski
- From the Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510,
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6
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Romero-Lorca A, Gaibar M, Armesilla AL, Fernandez-Santander A, Novillo A. Differential expression of PMCA2 mRNA isoforms in a cohort of Spanish patients with breast tumor types. Oncol Lett 2018; 16:6950-6959. [PMID: 30546427 PMCID: PMC6256341 DOI: 10.3892/ol.2018.9540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/29/2018] [Indexed: 01/01/2023] Open
Abstract
The present study examined the mRNA expression levels of different isoforms of the plasma membrane calcium ATPase 2 (PMCA2) gene generated by alternative splicing at the first intracellular loop (site A) and C-terminal region (site C) in 85 human breast cancer tumor and 69 adjacent non-tumor tissues. Associations were identified between the expression of PMCA2 splice isoforms and the following clinical variables: Estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status, tumor size, staging and histological classification, and lymph node status. Transcripts including splice site A or splice site C were amplified by reverse transcription-quantitative polymerase chain reaction using PMCA2 isoform-specific primers. Tumor and adjacent tissues were determined to express the different PMCA2 splice isoforms 2w, 2× and 2z (site A), and 2b (site C). The mRNA levels for these variants indicated high biological variability, but increased expression was observed in breast tumor tissues, compared with in adjacent tissues. Significantly increased PMCA2×/b expression levels were detected in breast tumor tissues histologically classified as lobulillar, compared with in ductal-types breast tumor tissues (P<0.028). Furthermore, PMCA2z expression was significantly associated with PR status (P<0.024, compared with in PR-negative tumor tissues), and PMCA2w expression was significantly associated with ER status (P<0.048, increased in ER-positive tumor tissues, compared with ER-negative tumor tissues). Finally, PMCA2b was overexpressed in HER2-positive tumor tissues, compared with in HER2-negative tumor tissues (P<0.014). The data demonstrated the differential mRNA expression of a number of splice site A and C variants of PMCA2 in breast tumor and adjacent tissues, depending on tumor hormone receptor status and histological classification. In agreement with previous data, PMCA2b was overexpressed in HER2-positive tumor tissues, indicating that high mRNA levels of this variant could be a marker of poor prognosis.
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Affiliation(s)
- Alicia Romero-Lorca
- Department of Basic Biomedical Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Madrid 28670, Spain
| | - Maria Gaibar
- Department of Basic Biomedical Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Madrid 28670, Spain
| | - Angel Luis Armesilla
- Faculty of Science and Engineering, School of Pharmacy, University of Wolverhampton, Wolverhampton, West Midlands WV1 1LY, UK
| | - Ana Fernandez-Santander
- Department of Basic Biomedical Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Madrid 28670, Spain
| | - Apolonia Novillo
- Department of Basic Biomedical Sciences, Faculty of Biomedical and Health Sciences, Universidad Europea de Madrid, Villaviciosa de Odón, Madrid 28670, Spain
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7
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Takahashi S, Sun W, Zhou Y, Homma K, Kachar B, Cheatham MA, Zheng J. Prestin Contributes to Membrane Compartmentalization and Is Required for Normal Innervation of Outer Hair Cells. Front Cell Neurosci 2018; 12:211. [PMID: 30079013 PMCID: PMC6062617 DOI: 10.3389/fncel.2018.00211] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/27/2018] [Indexed: 12/16/2022] Open
Abstract
Outer hair cells (OHC) act as amplifiers and their function is modified by medial olivocochlear (MOC) efferents. The unique OHC motor protein, prestin, provides the molecular basis for somatic electromotility, which is required for sensitivity and frequency selectivity, the hallmarks of mammalian hearing. Prestin proteins are the major component of the lateral membrane of mature OHCs, which separates apical and basal domains. To investigate the contribution of prestin to this unique arrangement, we compared the distribution of membrane proteins in OHCs of wildtype (WT) and prestin-knockout (KO) mice. In WT, the apical protein PMCA2 was exclusively localized to the hair bundles, while it was also found at the lateral membrane in KOs. Similarly, a basal protein KCNQ4 did not coalesce at the base of OHCs but was widely dispersed in mice lacking prestin. Since the expression levels of PMCA2 and KCNQ4 remained unchanged in KOs, the data indicate that prestin is required for the normal distribution of apical and basal membrane proteins in OHCs. Since OHC synapses predominate in the basal subnuclear region, we also examined the synaptic architecture in prestin-KO mice. Although neurite densities were not affected, MOC efferent terminals in prestin-KO mice were no longer constrained to the basal pole as in WT. This trend was evident as early as at postnatal day 12. Furthermore, terminals were often enlarged and frequently appeared as singlets when compared to the multiple clusters of individual terminals in WT. This abnormality in MOC synaptic morphology in prestin-KO mice is similar to defects in mice lacking MOC pathway proteins such as α9/α10 nicotinic acetylcholine receptors and BK channels, indicating a role for prestin in the proper establishment of MOC synapses. To investigate the contribution of prestin’s electromotility, we also examined OHCs from a mouse model that expresses non-functional prestin (499-prestin). We found no changes in PMCA2 localization and MOC synaptic morphology in OHCs from 499-prestin mice. Taken together, these results indicate that prestin, independent of its motile function, plays an important structural role in membrane compartmentalization, which is required for the formation of normal efferent-OHC synapses in mature OHCs.
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Affiliation(s)
- Satoe Takahashi
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Willy Sun
- Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Yingjie Zhou
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States
| | - Kazuaki Homma
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,The Knowles Hearing Center, Northwestern University, Evanston, IL, United States
| | - Bechara Kachar
- Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Mary Ann Cheatham
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States.,The Knowles Hearing Center, Northwestern University, Evanston, IL, United States
| | - Jing Zheng
- Department of Otolaryngology - Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, United States.,The Knowles Hearing Center, Northwestern University, Evanston, IL, United States
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Roome CJ, Empson RM. Survival strategies for mouse cerebellar Purkinje neurons lacking PMCA2. Neurosci Lett 2018; 663:25-28. [PMID: 29452612 DOI: 10.1016/j.neulet.2017.09.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 09/23/2017] [Indexed: 11/25/2022]
Abstract
Expression of the fast calcium extrusion protein, PMCA2, in the cerebellum is amongst the highest found throughout the central nervous system, and unsurprisingly PMCA2 knockout mice exhibit cerebellar ataxia or loss of controlled movement. The sole output neurons of the cerebellar cortex, Purkinje neurons, are functionally compromised in these knockout mice, yet remarkably these neurons survive. In this mini-review we review and speculate on the importance of multiple PMCA2 dependent actions at cellular and synaptic sites within the cerebellar Purkinje neuron network. We also explore how loss of PMCA2-/- can lead to the ataxic phenotype, but can paradoxically also minimise calcium rises in cerebellar Purkinje neurons, thereby ensuring their resilience and survival.
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Affiliation(s)
- Christopher J Roome
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Okinawa, 904-0495, Japan.
| | - Ruth M Empson
- Department of Physiology, School of Biomedical Sciences, Brain Health Research Centre, Brain Research New Zealand, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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9
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Weatherstone JH, Kopp-Scheinpflug C, Pilati N, Wang Y, Forsythe ID, Rubel EW, Tempel BL. Maintenance of neuronal size gradient in MNTB requires sound-evoked activity. J Neurophysiol 2016; 117:756-766. [PMID: 27881722 PMCID: PMC5304411 DOI: 10.1152/jn.00528.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 11/21/2016] [Indexed: 12/12/2022] Open
Abstract
Neurons of the medial nucleus of the trapezoid body (MNTB) act as fast-spiking inhibitory interneurons within the auditory brain stem. The MNTB is topographically organized, with low sound frequencies encoded laterally and high frequencies medially. We discovered a cell size gradient along this axis: lateral neurons are larger than medial neurons. The absence of this gradient in deaf mice lacking plasma membrane calcium ATPase 2 suggests an activity-dependent, calcium-mediated mechanism that controls neuronal soma size. The medial nucleus of the trapezoid body (MNTB) is an important source of inhibition during the computation of sound location. It transmits fast and precisely timed action potentials at high frequencies; this requires an efficient calcium clearance mechanism, in which plasma membrane calcium ATPase 2 (PMCA2) is a key component. Deafwaddler (dfw2J) mutant mice have a null mutation in PMCA2 causing deafness in homozygotes (dfw2J/dfw2J) and high-frequency hearing loss in heterozygotes (+/dfw2J). Despite the deafness phenotype, no significant differences in MNTB volume or cell number were observed in dfw2J homozygous mutants, suggesting that PMCA2 is not required for MNTB neuron survival. The MNTB tonotopic axis encodes high to low sound frequencies across the medial to lateral dimension. We discovered a cell size gradient along this axis: lateral neuronal somata are significantly larger than medially located somata. This size gradient is decreased in +/dfw2J and absent in dfw2J/dfw2J. The lack of acoustically driven input suggests that sound-evoked activity is required for maintenance of the cell size gradient. This hypothesis was corroborated by selective elimination of auditory hair cell activity with either hair cell elimination in Pou4f3 DTR mice or inner ear tetrodotoxin (TTX) treatment. The change in soma size was reversible and recovered within 7 days of TTX treatment, suggesting that regulation of the gradient is dependent on synaptic activity and that these changes are plastic rather than permanent. NEW & NOTEWORTHY Neurons of the medial nucleus of the trapezoid body (MNTB) act as fast-spiking inhibitory interneurons within the auditory brain stem. The MNTB is topographically organized, with low sound frequencies encoded laterally and high frequencies medially. We discovered a cell size gradient along this axis: lateral neurons are larger than medial neurons. The absence of this gradient in deaf mice lacking plasma membrane calcium ATPase 2 suggests an activity-dependent, calcium-mediated mechanism that controls neuronal soma size.
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Affiliation(s)
- Jessica H Weatherstone
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington.,Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington
| | - Conny Kopp-Scheinpflug
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; .,Division of Neurobiology, Department Biology II, Ludwig-Maximilians University Munich, Planegg-Martinsried, Germany
| | - Nadia Pilati
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom.,Autifony Srl Laboratories, Medicines Research Centre, Verona, Italy; and
| | - Yuan Wang
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington.,Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida
| | - Ian D Forsythe
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Edwin W Rubel
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington
| | - Bruce L Tempel
- Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington.,Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, and Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington
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10
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Curry M, Roberts-Thomson SJ, Monteith GR. PMCA2 silencing potentiates MDA-MB-231 breast cancer cell death initiated with the Bcl-2 inhibitor ABT-263. Biochem Biophys Res Commun 2016; 478:1792-7. [PMID: 27613092 DOI: 10.1016/j.bbrc.2016.09.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 12/15/2022]
Abstract
PMCA2 overexpression in some breast cancers suggests that this calcium pump isoform may play a role in breast pathophysiology. To investigate PMCA2 as a potential drug target for breast cancer therapy, we assessed the functional consequence of PMCA2 silencing on cell death pathways and calcium signals in the basal-like MDA-MB-231 breast cancer cell line. Silencing PMCA2 expression alone has no effect on MDA-MB-231 cell viability, however, PMCA2 silencing promotes calcium-induced cell death initiated with the calcium ionophore ionomycin. Assessment of cytoplasmic calcium responses generated with various agents including ionomycin demonstrates that in MDA-MB-231 cells, PMCA2 does not play a major role in shaping global calcium signals. We also examined the ability of PMCA2 silencing to modulate caspase-dependent cell death triggered by a Bcl-2 inhibitor that is in clinical development for the treatment of various cancers, ABT-263 (Navitoclax). Despite the lack of effect on global calcium responses, PMCA2 silencing augmented Bcl-2 inhibitor (ABT-263)-mediated MDA-MB-231 breast cancer cell death. These studies provide evidence that PMCA2 inhibitors could sensitize PMCA2-positive breast cancers to cell death initiators that work through mechanisms involving the Bcl-2 survival pathway.
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Abstract
Lactation is the most extreme case of normal physiological bone loss during a lifetime, and breast cancers have a strong tendency to metastasize to bone. In both the physiological and pathological circumstances, parathyroid hormone-related peptide (PTHrP) plays a central role. Until recently there were no regulatory mechanisms to explain the induction of endocrine PTHrP secretion from breast cells during lactation. The mammary epithelium possesses a local serotonin signaling system which drives PTHrP expression during lactation and in breast cancer cells. The mammary gland serotonin system is highly induced in response to alveolar dilation due to milk secretion. Discovery of serotonergic control of PTHrP suggests that it may be possible to manipulate the breast-to-bone axis by targeting serotonin signaling.
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Affiliation(s)
- Nelson D Horseman
- Department of Molecular and Cellular Physiology, Program in Systems Biology and Physiology, University of Cincinnati, Cincinnati, OH 45267-0576, USA.
| | - Laura L Hernandez
- Department of Dairy Science, University of Wisconsin, Madison, Madison, WI 53706-1205, USA
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12
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Brendel A, Renziehausen J, Behl C, Hajieva P. Downregulation of PMCA2 increases the vulnerability of midbrain neurons to mitochondrial complex I inhibition. Neurotoxicology 2013; 40:43-51. [PMID: 24269647 DOI: 10.1016/j.neuro.2013.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 10/26/2013] [Accepted: 11/12/2013] [Indexed: 12/28/2022]
Abstract
Parkinson's disease is an age-associated disorder characterized by selective degeneration of dopaminergic neurons. The molecular mechanisms underlying the selective vulnerability of this subset of neurons are, however, not fully understood. Employing SH-SY5Y neuroblastoma cells and primary mesencephalic neurons, we here demonstrate a significant increase in cytosolic calcium after inhibition of mitochondrial complex I by means of MPP(+), which is a well-established environmental toxin-based in vitro model of Parkinson's disease. This increase in calcium is correlated with a downregulation of the neuron-specific plasma membrane Ca(2+)-ATPase isoform 2 (PMCA2). Interestingly, two other important mediators of calcium efflux, sarcoplasmic reticulum Ca(2+)-ATPase (SERCA), and Na(+)-Ca(2+)-exchanger (NCX), remained unaltered, indicating a specific role of PMCA2 in maintaining calcium homeostasis in neurons. The observed PMCA2 downregulation was accompanied by reduced levels of phosphorylated CREB protein, an intracellular signaling molecule and transcriptional regulator. In order to investigate the potential influence of PMCA2 on neuronal vulnerability, experimental downregulation of PMCA2 by means of siRNA was performed. The results demonstrate a significant impairment of cell survival under conditions of PMCA2 suppression. Hence, in our cell models increased cytosolic calcium levels as a consequence of insufficient calcium efflux lead to an increased vulnerability of neuronal cells. Moreover, overexpression of PMCA2 rendered the neurons significantly resistant to complex I inhibition. Our findings point toward a dysregulation of calcium homeostasis in Parkinson's disease and suggest a potential molecular mechanism of neurodegeneration via PMCA2.
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Affiliation(s)
- Alexander Brendel
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Duesbergweg 6, 55099 Mainz, Germany
| | - Jana Renziehausen
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Duesbergweg 6, 55099 Mainz, Germany
| | - Christian Behl
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Duesbergweg 6, 55099 Mainz, Germany
| | - Parvana Hajieva
- Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Duesbergweg 6, 55099 Mainz, Germany.
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Abstract
Normal breast epithelial cells and breast cancer cells express the calcium-sensing receptor (CaSR), the master regulator of systemic calcium metabolism. During lactation, activation of the CaSR in mammary epithelial cells downregulates parathyroid hormone-related protein (PTHrP) levels in milk and in the circulation, and increases calcium transport into milk. In contrast, in breast cancer cells the CaSR upregulates PTHrP production. A switch in G-protein usage underlies the opposing effects of the CaSR on PTHrP expression in normal and malignant breast cells. During lactation, the CaSR in normal breast cells coordinates a feedback loop that matches the transport of calcium into milk and maternal calcium metabolism to the supply of calcium. A switch in CaSR G-protein usage during malignant transformation converts this feedback loop into a feed-forward cycle in breast cancer cells that may promote the growth of osteolytic skeletal metastases.
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Affiliation(s)
- Joshua N Vanhouten
- Section of Endocrinology and Metabolism, Department of Internal Medicine, Yale University School of Medicine, TAC S131, Box 208020, New Haven, CT, USA.
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