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Wiebe SA, Plain A, Pan W, O’Neill D, Braam B, Alexander RT. NHE8 attenuates Ca2+ influx into NRK cells and the proximal tubule epithelium. Am J Physiol Renal Physiol 2019; 317:F240-F253. [DOI: 10.1152/ajprenal.00329.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To garner insights into the renal regulation of Ca2+ homeostasis, we performed an mRNA microarray on kidneys from mice treated with the Ca2+-sensing receptor (CaSR) agonist cinacalcet. This revealed decreased gene expression of Na+/H+ exchanger isoform 8 (NHE8) in response to CaSR activation. These results were confirmed by quantitative real-time PCR. Moreover, administration of vitamin D also decreased NHE8 mRNA expression. In contrast, renal NHE8 protein expression from the same samples was increased. To examine the role of NHE8 in transmembrane Ca2+ fluxes, we used the normal rat kidney (NRK) cell line. Cell surface biotinylation and confocal immunofluorescence microscopy demonstrated NHE8 apical expression. Functional experiments found 5-( N-ethyl- N-isopropyl)amiloride (EIPA)-inhibitable NHE activity in NRK cells at concentrations minimally attenuating NHE1 activity in AP-1 cells. To determine how NHE8 might regulate Ca2+ balance, we measured changes in intracellular Ca2+ uptake by live cell Ca2+ imaging with the fluorophore Fura-2 AM. Inhibition of NHE8 with EIPA or by removing extracellular Na+-enhanced Ca2+ influx into NRK cells. Ca2+ influx was mediated by a voltage-dependent Ca2+ channel rather than directly via NHE8. NRK cells express Cav1.3 and display verapamil-sensitive Ca2+ influx and NHE8 inhibition-augmented Ca2+ influx via a voltage-dependent Ca2+ channel. Finally, proximal tubules perused ex vivo demonstrated increased Ca2+ influx in the presence of luminal EIPA at a concentration that would inhibit NHE8. The results of the present study are consistent with NHE8 regulating Ca2+ uptake into the proximal tubule epithelium.
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Affiliation(s)
- Shane A. Wiebe
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Allein Plain
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Wanling Pan
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Debbie O’Neill
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Branko Braam
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Division of Nephrology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - R. Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
- The Women’s & Children’s Health Research Institute, Edmonton, Alberta, Canada
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YAMAGUCHI MASAYOSHI. The potential role of regucalcin in kidney cell regulation: Involvement in renal failure (Review). Int J Mol Med 2015; 36:1191-9. [DOI: 10.3892/ijmm.2015.2343] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/09/2015] [Indexed: 11/06/2022] Open
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3
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Marques R, Peres CG, Vaz CV, Gomes IM, Figueira MI, Cairrão E, Verde I, Maia CJ, Socorro S. 5α-Dihydrotestosterone regulates the expression of L-type calcium channels and calcium-binding protein regucalcin in human breast cancer cells with suppression of cell growth. Med Oncol 2015; 32:228. [PMID: 26255063 DOI: 10.1007/s12032-015-0676-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/03/2015] [Indexed: 12/20/2022]
Abstract
Androgens have been associated with the development of normal breast, and their role in mammary gland carcinogenesis has also been described. Several studies reported that androgens inhibit breast cancer cell growth, whereas others linked their action with the modulation of calcium (Ca(2+)) pumps, Ca(2+) channels and Ca(2+)-binding proteins. Also, it is known that deregulated Ca(2+) homeostasis has been implicated in the pathophysiology of breast. The L-type Ca(2+) channels (LTCCs) were found to be up-regulated in colon, colorectal and prostate cancer, but their presence in breast tissues remains uncharacterized. On the other hand, regucalcin (RGN) is a Ca(2+)-binding protein involved in the control of mammary gland cell proliferation, which has been identified as an androgen target gene in distinct tissues except breast. This study aimed to confirm the expression and activity of LTCCs in human breast cancer cells and investigate the effect of androgens in regulating the expression of α1C subunit (Cav1.2) of LTCCs and Ca(2+)-binding protein RGN. PCR, Western blot, immunofluorescence and electrophysiological experiments demonstrated the expression and activity of Cav1.2 subunit in MCF-7 cells. The MCF-7 cells were treated with 1, 10 or 100 nM of 5α-dihydrotestosterone (DHT) for 24-72 h. The obtained results showed that 1 nM DHT up-regulated the expression of Cav1.2 subunit while diminishing RGN protein levels, which was underpinned by reduced cell viability. These findings first confirmed the presence of LTCCs in breast cancer cells and opened new perspectives for the development of therapeutic approaches targeting Ca(2+) signaling.
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Affiliation(s)
- Ricardo Marques
- Faculdade de Ciências da Saúde, CICS-UBI - Health Sciences Research Center, University of Beira Interior, Av. Infante D. Henrique, 6200-506, Covilhã, Portugal
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4
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Vaz CV, Rodrigues DB, Socorro S, Maia CJ. Effect of extracellular calcium on regucalcin expression and cell viability in neoplastic and non-neoplastic human prostate cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2621-8. [PMID: 26171977 DOI: 10.1016/j.bbamcr.2015.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 07/06/2015] [Accepted: 07/10/2015] [Indexed: 01/14/2023]
Abstract
Extracellular calcium (Ca2+o) and its receptor, the Ca2+-sensing receptor (CaSR), play an important role in prostate physiology, and it has been shown that the deregulation of Ca2+ homeostasis and the overexpression of CaSR are involved in prostate cancer (PCa). Regucalcin (RGN), a Ca2+-binding protein that plays a relevant role in intracellular Ca2+ homeostasis, was identified as an under-expressed protein in human PCa. Moreover, RGN was associated with suppression of cell proliferation, suggesting that the loss of RGN may favor development and progression of PCa. This work aims to unveil the role of Ca2+o on RGN expression and viability of non-neoplastic (PNT1A) and neoplastic (LNCaP) prostate cell lines. It was demonstrated that Ca2+o up-regulates RGN expression in both cell lines, but important differences were found between cells for dose- and time-responses to Ca2+o treatment. It was also shown that high [Ca2+]o triggers different effects on cell proliferation of neoplastic and non-neoplastic PCa cells, which seems to be related with RGN expression levels. This suggests the involvement of RGN in the regulation of cell proliferation in response to Ca2+o treatment. Also, the effect of Ca2+o on CaSR expression seems to be dependent of RGN expression, which is strengthened by the fact that RGN-knockdown in PNT1A cells increases the CaSR expression, whereas transgenic rats overexpressing RGN exhibit low levels of CaSR. Overall, our results highlighted the importance of RGN as a regulatory protein in Ca2+-dependent signaling pathways and its deregulation of RGN expression by Ca2+o may contribute for onset and progression of PCa.
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Affiliation(s)
- Cátia V Vaz
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Daniel B Rodrigues
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal
| | - Sílvia Socorro
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Cláudio J Maia
- CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
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5
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Pauletto M, Milan M, de Sousa JT, Huvet A, Joaquim S, Matias D, Leitão A, Patarnello T, Bargelloni L. Insights into molecular features of Venerupis decussata oocytes: a microarray-based study. PLoS One 2014; 9:e113925. [PMID: 25470487 PMCID: PMC4254928 DOI: 10.1371/journal.pone.0113925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 10/31/2014] [Indexed: 11/18/2022] Open
Abstract
The production of Venerupis decussata relies on wild seed collection, which has been recently compromised due to recruitment failure and severe mortalities. To address this issue and provide an alternative source of seed, artificial spawning and larval rearing programs were developed. However, hatchery-based seed production is a relatively new industry and it is still underdeveloped. A major hurdle in the European clam seed production is the control of spawning and reproduction, which is further hindered by the impossibility of obtaining fertile gametes by gonadal "stripping", as meiosis re-initiation is constrained to a maturation process along the genital ducts. In the present study, oocytes were collected from 15 females and microarray analyses was performed to investigate gene expression profiles characterizing released and stripped ovarian oocytes. A total of 198 differentially expressed transcripts between stripped and spawned oocytes were detected. Functional analysis carried out on these transcripts highlighted the importance of a few biological processes, which are most probably implicated in the control of oocyte competence. Significant differences were observed for transcripts encoding proteins involved in meiosis progression (e.g. dual specificity phosphatase CDC25), WNT signalling (e.g. frizzled class receptor 8, wingless-type MMTV integration site family member 4), steroid synthesis (e.g. progestin and adipoQ receptor family member 3, cytochrome P450-C17), mRNA processing (e.g. zinc finger protein XlCOF28), calcium regulation (e.g. regucalcin, calmodulin) and ceramide metabolism (ceramidase B, sphingomyelinase). This study provides new information on transcriptional profiles putatively associated with ovarian egg infertility, and suggests potential mechanisms regulating early oocyte development in clams. Genes which were differentially expressed between stripped and spawned oocytes might have a pivotal role during maturation process in the gonadal duct and could be interesting targets for further functional studies aiming to make ovarian oocytes fertilizable.
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Affiliation(s)
- Marianna Pauletto
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
- * E-mail:
| | - Massimo Milan
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Joana Teixeira de Sousa
- IFREMER, Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire des Sciences de l’Environnement Marin, Plouzané, France
- IPMA, Instituto Português do Mar e da Atmosfera, Olhão, Portugal
| | - Arnaud Huvet
- IFREMER, Institut Français de Recherche pour l’Exploitation de la Mer, Laboratoire des Sciences de l’Environnement Marin, Plouzané, France
| | - Sandra Joaquim
- IPMA, Instituto Português do Mar e da Atmosfera, Olhão, Portugal
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
| | - Domitília Matias
- IPMA, Instituto Português do Mar e da Atmosfera, Olhão, Portugal
- CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
| | - Alexandra Leitão
- IPMA, Instituto Português do Mar e da Atmosfera, Olhão, Portugal
- Environmental Studies Center, Qatar University, Doha, Qatar
| | - Tomaso Patarnello
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
| | - Luca Bargelloni
- Department of Comparative Biomedicine and Food Science, University of Padova, Legnaro, Italy
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6
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Jin X, Mohieldin AM, Muntean BS, Green JA, Shah JV, Mykytyn K, Nauli SM. Cilioplasm is a cellular compartment for calcium signaling in response to mechanical and chemical stimuli. Cell Mol Life Sci 2014; 71:2165-78. [PMID: 24104765 PMCID: PMC3981964 DOI: 10.1007/s00018-013-1483-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 12/23/2022]
Abstract
Primary cilia with a diameter of ~200 nm have been implicated in development and disease. Calcium signaling within a primary cilium has never been directly visualized and has therefore remained a speculation. Fluid-shear stress and dopamine receptor type-5 (DR5) agonist are among the few stimuli that require cilia for intracellular calcium signal transduction. However, it is not known if these stimuli initiate calcium signaling within the cilium or if the calcium signal originates in the cytoplasm. Using an integrated single-cell imaging technique, we demonstrate for the first time that calcium signaling triggered by fluid-shear stress initiates in the primary cilium and can be distinguished from the subsequent cytosolic calcium response through the ryanodine receptor. Importantly, this flow-induced calcium signaling depends on the ciliary polycystin-2 calcium channel. While DR5-specific agonist induces calcium signaling mainly in the cilioplasm via ciliary CaV1.2, thrombin specifically induces cytosolic calcium signaling through the IP3 receptor. Furthermore, a non-specific calcium ionophore triggers both ciliary and cytosolic calcium responses. We suggest that cilia not only act as sensory organelles but also function as calcium signaling compartments. Cilium-dependent signaling can spread to the cytoplasm or be contained within the cilioplasm. Our study thus provides the first model to understand signaling within the cilioplasm of a living cell.
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MESH Headings
- Animals
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Ionophores/pharmacology
- Calcium Signaling
- Cilia/drug effects
- Cilia/metabolism
- Cytoplasm/drug effects
- Cytoplasm/metabolism
- Epithelial Cells/cytology
- Epithelial Cells/drug effects
- Epithelial Cells/metabolism
- Gene Expression Regulation
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Kidney/cytology
- Kidney/drug effects
- Kidney/metabolism
- Mechanotransduction, Cellular
- Molecular Imaging
- Primary Cell Culture
- Receptors, TNF-Related Apoptosis-Inducing Ligand/genetics
- Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism
- Rheology
- Ryanodine Receptor Calcium Release Channel/genetics
- Ryanodine Receptor Calcium Release Channel/metabolism
- Single-Cell Analysis
- Stress, Mechanical
- Swine
- TRPP Cation Channels/genetics
- TRPP Cation Channels/metabolism
- Thrombin/pharmacology
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Affiliation(s)
- Xingjian Jin
- Department of Medicine, College of Medicine, The University of Toledo, Toledo, OH 43606 USA
| | - Ashraf M. Mohieldin
- Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, OH 43606 USA
| | - Brian S. Muntean
- Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, OH 43606 USA
| | - Jill A. Green
- Department of Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Jagesh V. Shah
- Department of Systems Biology, Harvard Medical School and Renal Division, Brigham and Women’s Hospital, Boston, MA 02115 USA
| | - Kirk Mykytyn
- Department of Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210 USA
| | - Surya M. Nauli
- Department of Medicine, College of Medicine, The University of Toledo, Toledo, OH 43606 USA
- Department of Pharmacology, College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, OH 43606 USA
- Department of Pharmacology, MS 1015, Health Education Building, Room 282D, The University of Toledo, 3000 Arlington Ave, Toledo, OH 43614 USA
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7
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Marques R, Maia CJ, Vaz C, Correia S, Socorro S. The diverse roles of calcium-binding protein regucalcin in cell biology: from tissue expression and signalling to disease. Cell Mol Life Sci 2014; 71:93-111. [PMID: 23519827 PMCID: PMC11113322 DOI: 10.1007/s00018-013-1323-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/21/2013] [Accepted: 03/07/2013] [Indexed: 02/06/2023]
Abstract
Regucalcin (RGN) is a calcium (Ca(2+))-binding protein widely expressed in vertebrate and invertebrate species, which is also known as senescence marker protein 30, due to its molecular weight (33 kDa) and a characteristically diminished expression with the aging process. RGN regulates intracellular Ca(2+) homeostasis and the activity of several proteins involved in intracellular signalling pathways, namely, kinases, phosphatases, phosphodiesterase, nitric oxide synthase and proteases, which highlights its importance in cell biology. In addition, RGN has cytoprotective effects reducing intracellular levels of oxidative stress, also playing a role in the control of cell survival and apoptosis. Multiple factors have been identified regulating the cell levels of RGN transcripts and protein, and an altered expression pattern of this interesting protein has been found in cases of reproductive disorders, neurodegenerative diseases and cancer. Moreover, RGN is a serum-secreted protein, and its levels have been correlated with the stage of disease, which strongly suggests the usefulness of this protein as a potential biomarker for monitoring disease onset and progression. The present review aims to discuss the available information concerning RGN expression and function in distinct cell types and tissues, integrating cellular and molecular mechanisms in the context of normal and pathological conditions. Insight into the cellular actions of RGN will be a key step towards deepening the knowledge of the biology of several human diseases.
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Affiliation(s)
- Ricardo Marques
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Cláudio J. Maia
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Cátia Vaz
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Sara Correia
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Sílvia Socorro
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
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8
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Yamaguchi M. Role of regucalcin in cell nuclear regulation: involvement as a transcription factor. Cell Tissue Res 2013; 354:331-41. [PMID: 23793546 DOI: 10.1007/s00441-013-1665-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 05/10/2013] [Indexed: 01/19/2023]
Abstract
Regucalcin (RGN/SMP30) was discovered in 1978 as a calcium (Ca(2+))-binding protein that contains no EF-hand motif of the Ca(2+)-binding domain. The name of regucalcin was proposed for this Ca(2+)-binding protein, which can regulate various Ca(2+)-dependent enzyme activations in liver cells. The regucalcin gene is localized on the X chromosome. Regucalcin plays a multifunctional role in cell regulation through maintaining intracellular Ca(2+) homeostasis and suppressing signal transduction in various cell types. The cytoplasmic regucalcin is translocated into the nucleus and inhibits nuclear Ca(2+)-dependent and -independent protein kinases and protein phosphatases, Ca(2+)-activated deoxyribonucleic acid (DNA) fragmentation and DNA and ribonucleic acid (RNA) synthesis. Moreover, overexpression of endogenous regucalcin regulates the gene expression of various proteins that are related to cell proliferation and apoptosis. This review will discuss the role of regucalcin in the regulation of cell nuclear function and an involvement in gene expression as a novel transcription factor.
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Affiliation(s)
- Masayoshi Yamaguchi
- Department of Hematology and Biomedical Oncology, Emory University School of Medicine, 1365 C Clifton Road, NE, Atlanta, GA, 30322, USA,
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Correia S, Oliveira PF, Guerreiro PM, Lopes G, Alves MG, Canario AVM, Cavaco JE, Socorro S. Sperm parameters and epididymis function in transgenic rats overexpressing the Ca2+-binding protein regucalcin: a hidden role for Ca2+ in sperm maturation? Mol Hum Reprod 2013; 19:581-9. [DOI: 10.1093/molehr/gat030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Spironolactone rescues Dot1a-Af9-mediated repression of endothelin-1 and improves kidney injury in streptozotocin-induced diabetic rats. PLoS One 2012; 7:e47360. [PMID: 23077601 PMCID: PMC3471839 DOI: 10.1371/journal.pone.0047360] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 09/11/2012] [Indexed: 01/01/2023] Open
Abstract
The molecular mechanism linking aldosterone and endothelin-1 in the development of diabetic nephropathy has not been completely elucidated. Here, we provide evidence showing that streptozotocin-induced diabetic rats have significantly increased aldosterone and endothelin-1 in the kidney tissue and markedly decreased expression of Dot1a and Af9. Blocking aldosterone with spironolactone significantly reduced proteinuria, glomerulosclerosis, tubulointerstitial injury and endothelin-1 expression, and significantly increased Dot1a and Af9 expression. Increasing Dot1a and Af9 expression by spironolactone or by stable transfection led to impaired endothelin-1 expression in NRK-52 cells. In contrast, downregulation of Dot1a and Af9 by aldosterone in NRK-52E cells caused upregulation of endothelin-1. Genetic inactivation of Dot1l, which encodes Dot1a, in Aqp2-expressing principal cells of mouse kidney impaired association of Dot1a and H3 dimethyl K79 with the specific subregions of endothelin-1 promoter, and upregulates endothelin-1 mRNA and protein expression. Our data suggest that Dot1a and Af9 repress endothelin-1 in vitro and in vivo. Excessive aldosterone induces kidney injury, in part possibly by downregulating Dot1a and Af9, and thus relieving Dot1a-Af9-mediated repression to increase endothelin-1 transcription. Spironolactone ameliorates kidney injury in Streptozotocin-induced diabetic rats, possibly by restoring Dot1a-Af9-mediated repression to reduce endothelin-1 expression. Therefore, Dot1a and Af9 as aldosterone-downregulated targets are negative regulators of endothelin-1 transcription in vitro and in vivo, and may be considered as new potential therapeutic targets of kidney injury in diabetes.
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Lai P, Yip NC, Michelangeli F. Regucalcin (RGN/SMP30) alters agonist- and thapsigargin-induced cytosolic [Ca2+] transients in cells by increasing SERCA Ca(2+)ATPase levels. FEBS Lett 2011; 585:2291-4. [PMID: 21684279 DOI: 10.1016/j.febslet.2011.05.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 05/26/2011] [Indexed: 10/18/2022]
Abstract
Regucalcin (RGN), also reported as senescence marker protein-30 (SMP30), plays a role in Ca(2+) homeostasis by modulating a number of Ca(2+)-dependent proteins. RGN also plays a cyto-protective role and its decrease is linked to age-related diseases and cell death. This study shows that RGN reduces agonist (histamine)-induced Ca(2+) transients in RGN(+) transfected COS-7 cells (RGN(+)) and also increases their Ca(2+) storage capacity. These observations are explained by RGN(+) cells having increased mRNA and protein expression levels of sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA). Therefore down-regulation of RGN expression may contribute to characteristics of age-dependent Ca(2+) homeostasis dis-regulation, by decreasing SERCA levels.
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Affiliation(s)
- Pei Lai
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, United Kingdom
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12
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Regucalcin and cell regulation: role as a suppressor protein in signal transduction. Mol Cell Biochem 2011; 353:101-37. [DOI: 10.1007/s11010-011-0779-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/07/2011] [Indexed: 12/23/2022]
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13
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Senescence marker protein 30 (SMP30) expression in eukaryotic cells: existence of multiple species and membrane localization. PLoS One 2011; 6:e16545. [PMID: 21347421 PMCID: PMC3036656 DOI: 10.1371/journal.pone.0016545] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 12/21/2010] [Indexed: 11/19/2022] Open
Abstract
Senescence marker protein (SMP30), also known as regucalcin, is a 34 kDa cytosolic marker protein of aging which plays an important role in intracellular Ca2+ homeostasis, ascorbic acid biosynthesis, oxidative stress, and detoxification of chemical warfare nerve agents. In our goal to investigate the activity of SMP30 for the detoxification of nerve agents, we have produced a recombinant adenovirus expressing human SMP30 as a fusion protein with a hemaglutinin tag (Ad-SMP30-HA). Ad-SMP30-HA transduced the expression of SMP30-HA and two additional forms of SMP30 with molecular sizes ∼28 kDa and 24 kDa in HEK-293A and C3A liver cells in a dose and time-dependent manner. Intravenous administration of Ad-SMP30-HA in mice results in the expression of all the three forms of SMP30 in the liver and diaphragm. LC-MS/MS results confirmed that the lower molecular weight 28 kDa and 24 kDa proteins are related to the 34 kDa SMP30. The 28 kDa and 24 kDa SMP30 forms were also detected in normal rat liver and mice injected with Ad-SMP30-HA suggesting that SMP30 does exist in multiple forms under physiological conditions. Time course experiments in both cell lines suggest that the 28 kDa and 24 kDa SMP30 forms are likely generated from the 34 kDa SMP30. Interestingly, the 28 kDa and 24 kDa SMP30 forms appeared initially in the cytosol and shifted to the particulate fraction. Studies using small molecule inhibitors of proteolytic pathways revealed the potential involvement of β and γ-secretases but not calpains, lysosomal proteases, proteasome and caspases. This is the first report describing the existence of multiple forms of SMP30, their preferential distribution to membranes and their generation through proteolysis possibly mediated by secretase enzymes.
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