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Zhong G, Long H, Chen F, Yu Y. Oxoglaucine mediates Ca 2+ influx and activates autophagy to alleviate osteoarthritis through the TRPV5/calmodulin/CAMK-II pathway. Br J Pharmacol 2021; 178:2931-2947. [PMID: 33786819 DOI: 10.1111/bph.15466] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/28/2020] [Accepted: 03/12/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Stimulation of calcium influx and suppression of autophagy play important roles in the pathogenesis of osteoarthritis (OA). In this study, we used a novel inhibitor of TRPV5 cation channels - oxoglaucine to attenuate progression of deterioration and pathological changes in OA patient-derived chondrocytes and OA animal model, by activating autophagy. EXPERIMENTAL APPROACH Inhibition by oxoglaucine of calcium influx was assessed in cells.. Analyses were also carried out to investigate the effect of oxoglaucine on OA by detection of anti-inflammatory response, TRPV5/CAMK-II/calmodulin pathway, autophagy, and cartilage protection both in vitro and in vivo. demonstrated by macroscopic evaluation and histological findings. KEY RESULTS Oxoglaucine suppressed expression of proinflammatory and apoptosis-related proteins, including TNF-α, IL-6, IL-1β, MMP-13, CASP-3, and BAX, and prevented matrix degradation in OA chondrocytes. It also successfully blocked Ca2+ influx, activating autophagy dose-dependently asshown by up-regulated expression of LC-3II/I, Beclin-1, ATG5, ATG7, higher autophagic influx and formation of autophagic vesicles. It also decreased expression of mRNA and protein of TRPV5, CAMK-II, and calmodulin. Conversely, 1,25-dihydroxyvitamin D3, anagonist of TRPV5 channels, reversed the oxoglaucine-induced calcium influx inhibition and autophagy activation, demonstrating the association of oxoglaucine with TRPV5. Further, oxoglaucine prevented the apoptosis and matrix degradation of articular cartilage in a rat model of OA. CONCLUSION AND IMPLICATIONS Oxoglaucine protects against cartilage damage by blocking the TRPV5/CAMK-II/calmodulin pathway to inhibit Ca2+ influx and activate autophagy. Our results indicate that oxoglaucine has the potential to become a candidate drug for treatment of OA.
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Affiliation(s)
- Gang Zhong
- Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Department of Neurology, Guangxi Medical University, Nanning, China
| | - Huiping Long
- Department of Neurology, Guangxi Medical University, Nanning, China
| | - Fei Chen
- Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yin Yu
- Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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Cao Q, Yin S. The influence of environmental calcium on the branchial morphology in a catadromous fish. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:8945-8952. [PMID: 33405148 DOI: 10.1007/s11356-020-11922-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
Eels are exposed to Ca2+ changes during migration between seawater and freshwater. The gill is the main organ of active calcium transport and has a large surface area to be particularly sensitive to environmental changes in the aquatic environment. In this research, we focused on the morphological changes of gill tissues when eels are faced with the environmental calcium challenges. Based on the results of hematoxylin and eosin (HE) staining and immunohistochemistry, compared with the control group (normal Ca2+ environment), the filament and lamella lengths and lamellar frequency (LF) appeared higher in high calcium environment and lower in deficient calcium environment, while the lamella width and filamental lamellar surface area (SAFL) decreased in high calcium environment and increased in deficient calcium environment. And there was no difference in the number filaments in first right gill arch in the three Ca2+ water environment. Transmission electron microscopy was employed to examine the ultrastructural changes in gills in different Ca2+ water environment. The nucleus and endoplasmic reticulum had a tendency to expand in calcium-deficient water, but had a tendency to shrink in high-calcium water comparing with the control group. This study provides the support that branchial surface areas are regulated in different Ca2+ waters through a list of calcium transporters including CACNB2.
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Affiliation(s)
- Quanquan Cao
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, China
| | - Shaowu Yin
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing, 210023, Jiangsu, China.
- Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, 222005, China.
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3
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Ng HM, Ho JCH, Nong W, Hui JHL, Lai KP, Wong CKC. Genome-wide analysis of MicroRNA-messenger RNA interactome in ex-vivo gill filaments, Anguilla japonica. BMC Genomics 2020; 21:208. [PMID: 32131732 PMCID: PMC7057501 DOI: 10.1186/s12864-020-6630-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/26/2020] [Indexed: 12/28/2022] Open
Abstract
Background Gills of euryhaline fishes possess great physiological and structural plasticity to adapt to large changes in external osmolality and to participate in ion uptake/excretion, which is essential for the re-establishment of fluid and electrolyte homeostasis. The osmoregulatory plasticity of gills provides an excellent model to study the role of microRNAs (miRs) in adaptive osmotic responses. The present study is to characterize an ex-vivo gill filament culture and using omics approach, to decipher the interaction between tonicity-responsive miRs and gene targets, in orchestrating the osmotic stress-induced responses. Results Ex-vivo gill filament culture was exposed to Leibovitz’s L-15 medium (300 mOsmol l− 1) or the medium with an adjusted osmolality of 600 mOsmol l− 1 for 4, 8 and 24 h. Hypertonic responsive genes, including osmotic stress transcriptional factor, Na+/Cl−-taurine transporter, Na+/H+ exchange regulatory cofactor, cystic fibrosis transmembrane regulator, inward rectifying K+ channel, Na+/K+-ATPase, and calcium-transporting ATPase were significantly upregulated, while the hypo-osmotic gene, V-type proton ATPase was downregulated. The data illustrated that the ex-vivo gill filament culture exhibited distinctive responses to hyperosmotic challenge. In the hyperosmotic treatment, four key factors (i.e. drosha RNase III endonuclease, exportin-5, dicer ribonuclease III and argonaute-2) involved in miR biogenesis were dysregulated (P < 0.05). Transcriptome and miR-sequencing of gill filament samples at 4 and 8 h were conducted and two downregulated miRs, miR-29b-3p and miR-200b-3p were identified. An inhibition of miR-29b-3p and miR-200b-3p in primary gill cell culture led to an upregulation of 100 and 93 gene transcripts, respectively. Commonly upregulated gene transcripts from the hyperosmotic experiments and miR-inhibition studies, were overlaid, in which two miR-29b-3p target-genes [Krueppel-like factor 4 (klf4), Homeobox protein Meis2] and one miR-200b-3p target-gene (slc17a5) were identified. Integrated miR-mRNA-omics analysis revealed the specific binding of miR-29b-3p on Klf4 and miR-200b-3p on slc17a5. The target-genes are known to regulate differentiation of gill ionocytes and cellular osmolality. Conclusions In this study, we have characterized the hypo-osmoregulatory responses and unraveled the modulation of miR-biogenesis factors/the dysregulation of miRs, using ex-vivo gill filament culture. MicroRNA-messenger RNA interactome analysis of miR-29b-3p and miR-200b-3p revealed the gene targets are essential for osmotic stress responses.
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Affiliation(s)
- Hoi Man Ng
- Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, HKSAR, Hong Kong
| | - Jeff Cheuk Hin Ho
- Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, HKSAR, Hong Kong
| | - Wenyan Nong
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, HKSAR, Hong Kong
| | - Jerome Ho Lam Hui
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, HKSAR, Hong Kong
| | - Keng Po Lai
- Guanxi Key Laboratory of Tumor Immunology and Microenvironmental Regulation, Guilin Medical University, Huan Cheng North 2nd Road 109, Guilin, 541004, People's Republic of China.
| | - Chris Kong Chu Wong
- Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon Tong, HKSAR, Hong Kong.
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Kosiba AA, Wang Y, Chen D, Wong CKC, Gu J, Shi H. The roles of calcium-sensing receptor (CaSR) in heavy metals-induced nephrotoxicity. Life Sci 2019; 242:117183. [PMID: 31874167 DOI: 10.1016/j.lfs.2019.117183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 02/06/2023]
Abstract
The kidney is a vital organ responsible for regulating water, electrolyte and acid-base balance as well as eliminating toxic substances from the blood in the body. Exposure of humans to heavy metals in their natural and occupational environments, foods, water, and drugs has serious implications on the kidney's health. The accumulation of heavy metals in the kidney has been linked to acute or chronic renal injury, kidney stones or even renal cancer, at the expense of expensive treatment options. Therefore, unearthing novel biomarkers and potential therapeutic agents or targets against kidney injury for efficient treatment are imperative. The calcium-sensing receptor (CaSR), a G-protein-coupled receptor (GPCR) is typically expressed in the parathyroid glands and renal tubules. It modulates parathyroid hormone secretion according to the serum calcium (Ca2+) concentration. In the kidney, it modulates electrolyte and water excretion by regulating the function of diverse tubular segments. Notably, CaSR lowers passive and active Ca2+ reabsorption in distal tubules, which facilitates phosphate reabsorption in proximal tubules and stimulates proton and water excretion in collecting ducts. Moreover, at the cellular level, modulation of the CaSR regulates cytosolic Ca2+ levels, reactive oxygen species (ROS) generation and the mitogen-activated protein kinase (MAPK) signaling cascades as well as autophagy and the suppression of apoptosis, an effect predominantly triggered by heavy metals. In this regard, we present a review on the CaSR at the cellular level and its potential as a therapeutic target for the development of new and efficient drugs against heavy metals-induced nephrotoxicity.
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Affiliation(s)
- Anthony A Kosiba
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yanwei Wang
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Dongfeng Chen
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Department of Rheumatology and Inflammation Research, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Chris Kong Chu Wong
- Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region
| | - Jie Gu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
| | - Haifeng Shi
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
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5
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Cao Q, Chu P, Gu J, Zhang H, Feng R, Wen X, Wang D, Xiong W, Wang T, Yin S. The influence of Ca 2+ concentration on voltage-dependent L-type calcium channels' expression in the marbled eel (Anguilla marmorata). Gene 2019; 722:144101. [PMID: 31479714 DOI: 10.1016/j.gene.2019.144101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 10/26/2022]
Abstract
The catadromous species, eels, invariably exposed to variable Ca2+ concentrations circumstance i.e., lagoon or ocean. They need to maintain Ca2+ homeostasis by exchanging Ca2+ under different culture conditions. To understand the effects of environmental Ca2+ to fish, three types of genes coding for voltage-dependent L-type calcium channels (cacnb1, 2, 3) were cloned by screening an A. marmorata cDNA library. Tissue distribution analysis of Western blot showed that Cacnb1, 2, 3 had a significantly high expression in gill; while mRNA results showed the expressions of cacnb1 and cacnb3 were predominated in skin tissue but only cacnb2 was expressed in intestine. Serum osmolality and Ca2+ concentrations of A.marmorata were increased in a high calcium environment while reduced in a low calcium environment within 7 days; however, they were not significantly different among Ca2+ treatments after the eels were acclimated for 7 days. We also examined the influence of ambient Ca2+ levels on cacnbs expression of eels. With the increasing of exposure time, mRNA and protein expressions of cacnb1 were up-regulated in high level of Ca2+ (10 mM) and down-regulated in deficient Ca2+ (0 mM) compared to the control Ca2+ (2 mM). However, the opposite results were observed in cacnb2 and cacnb3. Notably, the cacnb2 expression was not significant different among Ca2+ treatments on day 7. Our study provided the insightful evidence that cacnbs play important roles in maintaining Ca2+ homeostasis of fish.
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Affiliation(s)
- Quanquan Cao
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Peng Chu
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Jie Gu
- Institute of Life Sciences, Jiangsu University, Zhenjiang, Jiangsu 212000, China
| | - Hongyan Zhang
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Runhua Feng
- School of WASM, Curtin University, WA 6151, Australia
| | - Xin Wen
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Dan Wang
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Wenfeng Xiong
- State Key Laboratory of Medical Genomics, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Tao Wang
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
| | - Shaowu Yin
- College of Marine Science and Engineering, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
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6
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Gu J, Dai S, Liu Y, Liu H, Zhang Y, Ji X, Yu F, Zhou Y, Chen L, Tse WKF, Wong CKC, Chen B, Shi H. Activation of Ca 2+-sensing receptor as a protective pathway to reduce Cadmium-induced cytotoxicity in renal proximal tubular cells. Sci Rep 2018; 8:1092. [PMID: 29348484 PMCID: PMC5773512 DOI: 10.1038/s41598-018-19327-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/27/2017] [Indexed: 01/16/2023] Open
Abstract
Cadmium (Cd), as an extremely toxic metal could accumulate in kidney and induce renal injury. Previous studies have proved that Cd impact on renal cell proliferation, autophagy and apoptosis, but the detoxification drugs and the functional mechanism are still in study. In this study, we used mouse renal tubular epithelial cells (mRTECs) to clarify Cd-induced toxicity and signaling pathways. Moreover, we proposed to elucidate the prevent effect of activation of Ca2+ sensing receptor (CaSR) by Calcimimetic (R-467) on Cd-induced cytotoxicity and underlying mechanisms. Cd induced intracellular Ca2+ elevation through phospholipase C-inositol 1, 4, 5-trisphosphate (PLC) followed stimulating p38 mitogen-activated protein kinases (MAPK) activation and suppressing extracellular signal-regulated kinase (ERK) activation, which leaded to increase apoptotic cell death and inhibit cell proliferation. Cd induced p38 activation also contribute to autophagic flux inhibition that aggravated Cd induced apoptosis. R-467 reinstated Cd-induced elevation of intracellular Ca2+ and apoptosis, and it also increased cell proliferation and restored autophagic flux by switching p38 to ERK pathway. The identification of the activation of CaSR-mediated protective pathway in renal cells sheds light on a possible cellular protective mechanism against Cd-induced kidney injury.
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Affiliation(s)
- Jie Gu
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Shuya Dai
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Yanmin Liu
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Haitao Liu
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Yao Zhang
- Medical Section, The Third Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Xingqi Ji
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Feng Yu
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Yang Zhou
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Liang Chen
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | | | - Chris Kong Chu Wong
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
| | - Binghai Chen
- Department of urology, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu, 212000, China
| | - Haifeng Shi
- Institute of Life Science, Jiangsu University, Zhenjiang, Jiangsu, 212000, China.
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Bai Y, Xiao Y, Dai Y, Chen X, Li D, Tan X, Zhang X. Stanniocalcin 1 promotes cell proliferation via cyclin E1/cyclin‑dependent kinase 2 in human prostate carcinoma. Oncol Rep 2017; 37:2465-2471. [PMID: 28350121 DOI: 10.3892/or.2017.5501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/23/2016] [Indexed: 11/06/2022] Open
Abstract
Stanniocalcin 1 (STC1) is a glycoprotein hormone that is involved in calcium/phosphate homeostasis. Increasing evidence suggests that STC1 is involved in carcinogenesis; however, few studies have defined the mechanisms and functional roles of STC1 activity in prostate carcinogenesis. In the present study, MTT, flow cytometry and colony formation assays, and small interfering RNA (siRNA) and overexpression in multiple cell lines were used to investigate the function of STC1 in prostate carcinoma in vivo and in vivo. Knockdown of endogenous STC1 using a siRNA decreased the proliferation of DU145 and LNCaP2 cells. These results were consistent with the changes in the protein levels of cyclin E1 and cyclin‑dependent kinase 2. By contrast, increased expression of STC1 in RWPE-1 cells led to increased cell proliferation, suggesting that STC1 promotes prostate carcinoma cell proliferation. In summary, the present study investigated the impact of STC1 on the proliferation and growth of prostate cancer in an effort to evaluate STC1 as a predictive biomarker and as a potential target for therapy.
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Affiliation(s)
- Yao Bai
- International Medical Center, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yichen Xiao
- The Medical College of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
| | - Yuanqing Dai
- Department of Geriatric Medicine, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xiong Chen
- International Medical Center, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Dongjie Li
- International Medical Center, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xinji Tan
- International Medical Center, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xiaobo Zhang
- International Medical Center, Xiang Ya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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8
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The potential role of polyamines in gill epithelial remodeling during extreme hypoosmotic challenges in the Gulf killifish, Fundulus grandis. Comp Biochem Physiol B Biochem Mol Biol 2016; 194-195:39-50. [DOI: 10.1016/j.cbpb.2016.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 01/05/2016] [Accepted: 01/05/2016] [Indexed: 02/04/2023]
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9
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Lai KP, Li JW, Gu J, Chan TF, Tse WKF, Wong CKC. Transcriptomic analysis reveals specific osmoregulatory adaptive responses in gill mitochondria-rich cells and pavement cells of the Japanese eel. BMC Genomics 2015; 16:1072. [PMID: 26678671 PMCID: PMC4683740 DOI: 10.1186/s12864-015-2271-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/03/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Homeostasis of ions and water is important for the maintenance of cellular functions. The regulation of the homeostasis is particularly important in euryhaline fish that migrate between freshwater (FW) and seawater (SW) environments. The fish gill, the major tissue that forms an interface separating the extracellular fluids and external water environment, has an effective transport system to maintain and regulate a constant body osmolality. In fish gills, the two major epithelial cells, pavement cells (PVCs) and mitochondria-rich cells (MRCs), are known to play key and complementary roles in ion transport at the interface. Discovering the robust mechanisms underlying the two cell types' response to osmotic stress would benefit our understanding of the fundamental mechanism allowing PVCs and MRCs to handle osmotic stress. Owing to the limited genomic data available on estuarine species, existing knowledge in this area is slim. In this study, transcriptome analyses were conducted using PVCs and MRCs isolated from Japanese eels adapted to FW or SW environments to provide a genome-wide molecular study to unravel the fundamental processes at work. RESULTS The study identified more than 12,000 transcripts in the gill cells. Interestingly, remarkable differential expressed genes (DEGs) were identified in PVCs (970 transcripts) instead of MRCs (400 transcripts) in gills of fish adapted to FW or SW. Since PVCs cover more than 90 % of the gill epithelial surface, the greater change in gene expression patterns in PVCs in response to external osmolality is anticipated. In the integrity pathway analysis, 19 common biological functions were identified in PVCs and MRCs. In the enriched signaling pathways analysis, most pathways differed between PVCs and MRCs; 14 enriched pathways were identified in PVCs and 12 in MRCs. The results suggest that the osmoregulatory responses in PVCs and MRCs are cell-type specific, which supports the complementary functions of the cells in osmoregulation. CONCLUSIONS This is the first study to provide transcriptomic analysis of PVCs and MRCs in gills of eels adapted to FW or SW environments. It describes the cell-type specific transcriptomic network in different tonicity. The findings consolidate the known osmoregulatory pathways and provide molecular insight in osmoregulation. The presented data will be useful for researchers to select their targets for further studies.
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Affiliation(s)
- Keng Po Lai
- School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Pokfulam Road, Pok Fu Lam, Hong Kong
| | - Jing-Woei Li
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong.,Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Je Gu
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Ting-Fung Chan
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - William Ka Fai Tse
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
| | - Chris Kong Chu Wong
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong. .,Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Pok Fu Lam, Hong Kong.
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10
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Gu J, Law AYS, Yeung BHY, Wong CKC. Characterization of stanniocalcin 1 binding and signaling in gill cells of Japanese eels. J Mol Endocrinol 2015; 54:305-14. [PMID: 25878057 DOI: 10.1530/jme-14-0320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/27/2015] [Indexed: 11/08/2022]
Abstract
Stanniocalcin 1 (STC1) is a hypocalcemic hormone that is known to play an important role in calcium metabolism in teleost fish. An increase in blood Ca(2) (+) levels stimulates its synthesis and release. The biological action of STC1 inhibits gill Ca(2) (+) transport (GCAT), but we as yet have no clear understanding of how STC1 inhibits GCAT. In the present study, we characterized the binding, signaling, and action of STC1 on gill cells. Treatment of gill cell cultures with the extracts of corpuscles of Stannius or recombinant STC1 proteins (STC1-V5) led to an increase in cytosolic cAMP levels. Using in situ ligand-binding assays, we demonstrated that STC1-V5 binds to both lamellar and inter-lamellar regions of gill sections. The binding sites were significantly increased in gill sections obtained from fish adapted to high-Ca(2) (+) (2 mM) freshwater (FW) as compared with those from fish adapted to low-Ca(2) (+) (0.2 mM) FW. Receptor-binding assays illustrated specific binding of STC1-alkaline phosphatase to plasma membrane (Kd of 0.36 nM), mitochondria (Kd of 0.41 nM), and nuclear (Kd of 0.71 nM) preparations from gill cells. STC1 binding capacity was significantly greater in the plasma membrane preparations of gills obtained from fish adapted to high-Ca(2) (+) FW. Using isolated pavement cells and mitochondria-rich cells in cAMP assays, we obtained results indicating that both cell types responded to STC1. To illustrate the biological action of STC1, we conducted Ca(2) (+) imaging experiments to demonstrate the effects of STC1 on thapsigargin-induced elevation of cytosolic Ca(2) (+). Our results indicated that STC1 exerted its inhibitory action via a cAMP pathway to lower intracellular Ca(2) (+) levels. Intriguingly, we were able to block the action of STC1 using an inhibitor, NS-398, of cyclooxygenase-2 (COX-2), which is known to stimulate the activity of sarcoplasmic and endoplasmic reticulum Ca(2) (+)-ATPase (SERCA). A follow-up experiment in which gill cells were incubated with STC1 revealed a downregulation of the epithelial Ca(2) (+) channel (ecacl) but an upregulation of cox-2 expression. The ECaCl is a gatekeeper for Ca(2) (+) entry, whereas COX-2 mediates an activation of SERCA. Taking these results together, the present study is, to our knowledge, the first to provide evidence of STC1 binding and signaling as well as the first to decipher the mechanism of the effect of STC1 on fish gills.
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Affiliation(s)
- J Gu
- Department of BiologyCroucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China
| | - A Y S Law
- Department of BiologyCroucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China
| | - B H Y Yeung
- Department of BiologyCroucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China
| | - Chris K C Wong
- Department of BiologyCroucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China
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