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Xiang Y, Fan D, An Q, Zhang T, Wu X, Ding J, Xu X, Yue G, Tang S, Du Q, Xu J, Xie R. Effects of Ion-Transporting Proteins on the Digestive System Under Hypoxia. Front Physiol 2022; 13:870243. [PMID: 36187789 PMCID: PMC9515906 DOI: 10.3389/fphys.2022.870243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Hypoxia refers to a state of oxygen limitation, which mainly mediates pathological processes in the human body and participates in the regulation of normal physiological processes. In the hypoxic environment, the main regulator of human body homeostasis is the hypoxia-inducible factor family (HIF). HIF can regulate the expression of many hypoxia-induced genes and then participate in various physiological and pathological processes of the human body. Ion-transporting proteins are extremely important types of proteins. Ion-transporting proteins are distributed on cell membranes or organelles and strictly control the inflow or outflow of ions in cells or organelles. Changes in ions in cells are often closely related to extensive physiological and pathological processes in the human body. Numerous studies have confirmed that hypoxia and its regulatory factors can regulate the transcription and expression of ion-transporting protein-related genes. Under hypoxic stress, the regulation and interaction of ion-transporting proteins by hypoxia often leads to diseases of various human systems and even tumors. Using ion-transporting proteins and hypoxia as targets to explore the mechanism of digestive system diseases and targeted therapy is expected to become a new breakthrough point.
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Affiliation(s)
- Yiwei Xiang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Dongdong Fan
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Qimin An
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Ting Zhang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Xianli Wu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Jianhong Ding
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Xiaolin Xu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Gengyu Yue
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Siqi Tang
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Qian Du
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
| | - Jingyu Xu
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
- *Correspondence: Jingyu Xu, ; Rui Xie,
| | - Rui Xie
- Department of Gastroenterology, Digestive Disease Hospital, Affiliated Hospital of Zunyi Medical University, Zunyi, China
- Collaborative Innovation Center of Tissue Damage Repair and Regeneration Medicine, Zunyi, China
- *Correspondence: Jingyu Xu, ; Rui Xie,
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Zhang Y, Ding J, Liu C, Luo S, Gao X, Wu Y, Wang J, Wang X, Wu X, Shen W, Zhu J. Genetics Responses to Hypoxia and Reoxygenation Stress in Larimichthys crocea Revealed via Transcriptome Analysis and Weighted Gene Co-Expression Network. Animals (Basel) 2021; 11:ani11113021. [PMID: 34827754 PMCID: PMC8614329 DOI: 10.3390/ani11113021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/26/2021] [Accepted: 09/29/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Hypoxia, which occurs frequently in aquaculture, can cause serious harm to all aspects of the growth, reproduction and metabolism of cultured fish. Due to the intolerance of Larimichthys crocea to hypoxia, Larimichthys crocea often floats head or even dies under hypoxic environment. However, the molecular mechanism of hypoxia tolerance in Larimichthys crocea has not been fully described. Therefore, the aim of this study was to explore the hub regulatory genes under hypoxic stress environment by transcriptome analysis of three key tissues (liver, blood and gill) in Larimichthys crocea. We identified a number of important genes that exercise different regulatory functions. Overall, this study will provide important clues to the molecular mechanisms of hypoxia tolerance in Larimichthys crocea. Abstract The large yellow croaker (Larimichthys crocea) is an important marine economic fish in China; however, its intolerance to hypoxia causes widespread mortality. To understand the molecular mechanisms underlying hypoxia tolerance in L. crocea, the transcriptome gene expression profiling of three different tissues (blood, gills, and liver) of L. crocea exposed to hypoxia and reoxygenation stress were performed. In parallel, the gene relationships were investigated based on weighted gene co-expression network analysis (WGCNA). Accordingly, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that several pathways (e.g., energy metabolism, signal transduction, oxygen transport, and osmotic regulation) may be involved in the response of L. crocea to hypoxia and reoxygenation stress. In addition, also, four key modules (darkorange, magenta, saddlebrown, and darkolivegreen) that were highly relevant to the samples were identified by WGCNA. Furthermore, some hub genes within the association module, including RPS16, EDRF1, KCNK5, SNAT2, PFKL, GSK-3β, and PIK3CD, were found. This is the first study to report the co-expression patterns of a gene network after hypoxia stress in marine fish. The results provide new clues for further research on the molecular mechanisms underlying hypoxia tolerance in L. crocea.
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Affiliation(s)
- Yibo Zhang
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
| | - Jie Ding
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
| | - Cheng Liu
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
| | - Shengyu Luo
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
| | - Xinming Gao
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
| | - Yuanjie Wu
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
| | - Jingqian Wang
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
| | - Xuelei Wang
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
| | - Xiongfei Wu
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
| | - Weiliang Shen
- State Key Laboratory of Large Yellow Croaker Breeding, Ningbo Academy of Oceanology and Fishery, Juxian Road, Ningbo 315103, China; (X.W.); (X.W.)
- Correspondence: (W.S.); (J.Z.); Tel.: +86-153-8137-7660 (W.S.); +86-139-5784-1679 (J.Z.)
| | - Junquan Zhu
- Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, 169 South Qixing Road, Ningbo 315832, China; (Y.Z.); (J.D.); (C.L.); (S.L.); (X.G.); (Y.W.); (J.W.)
- Correspondence: (W.S.); (J.Z.); Tel.: +86-153-8137-7660 (W.S.); +86-139-5784-1679 (J.Z.)
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Endo K, Kito H, Tanaka R, Kajikuri J, Tanaka S, Elboray EE, Suzuki T, Ohya S. Possible Contribution of Inflammation-Associated Hypoxia to Increased K 2P5.1 K + Channel Expression in CD4 + T cells of the Mouse Model for Inflammatory Bowel Disease. Int J Mol Sci 2019; 21:ijms21010038. [PMID: 31861667 PMCID: PMC6981474 DOI: 10.3390/ijms21010038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/10/2019] [Accepted: 12/17/2019] [Indexed: 01/03/2023] Open
Abstract
Previous studies have reported the up-regulation of the two-pore domain K+ channel K2P5.1 in the CD4+ T cells of patients with multiple sclerosis (MS) and rheumatoid arthritis (RA), as well as in a mouse model of inflammatory bowel disease (IBD). However, the mechanisms underlying this up-regulation remain unclear. Inflammation-associated hypoxia is involved in the pathogenesis of autoimmune diseases, such as IBD, MS, and RA, and T cells are exposed to a hypoxic environment during their recruitment from inflamed tissues to secondary lymphoid tissues. We herein investigated whether inflammation-associated hypoxia is attributable to the increased expression and activity of K2P5.1 in the splenic CD4+ T cells of chemically-induced IBD model mice. Significant increases in hypoxia-inducible factor (HIF)-1α transcripts and proteins were found in the splenic CD4+ T cells of the IBD model. In the activated splenic CD4+ T cells, hypoxia (1.5% O2) increased K2P5.1 expression and activity, whereas a treatment with the HIF inhibitor FM19G11 but not the selective HIF-2 inhibitor exerted the opposite effect. Hypoxia-exposed K2P5.1 up-regulation was also detected in stimulated thymocytes and the mouse T-cell line. The class III histone deacetylase sirtuin-1 (SIRT1) is a downstream molecule of HIF-1α signaling. We examined the effects of the SIRT1 inhibitor NCO-01 on K2P5.1 transcription in activated CD4+ T cells, and we found no significant effects on the K2P5.1 transcription. No acute compensatory responses of K2P3.1–K2P5.1 up-regulation were found in the CD4+ T cells of the IBD model and the hypoxia-exposed T cells. Collectively, these results suggest a mechanism for K2P5.1 up-regulation via HIF-1 in the CD4+ T cells of the IBD model.
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Affiliation(s)
- Kyoko Endo
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Hiroaki Kito
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Ryo Tanaka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
| | - Junko Kajikuri
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
| | - Satoshi Tanaka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan; (K.E.); (R.T.); (S.T.)
| | - Elghareeb E. Elboray
- Department of Complex Molecular Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan; (E.E.E.); (T.S.)
- Faculty of Science, South Valley University, Qena 83523, Egypt
| | - Takayoshi Suzuki
- Department of Complex Molecular Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan; (E.E.E.); (T.S.)
| | - Susumu Ohya
- Department of Pharmacology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan; (H.K.); (J.K.)
- Correspondence: ; Tel.: +81-52-853-8149
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Ohya S, Kito H, Hatano N, Muraki K. Recent advances in therapeutic strategies that focus on the regulation of ion channel expression. Pharmacol Ther 2016; 160:11-43. [PMID: 26896566 DOI: 10.1016/j.pharmthera.2016.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of different ion channel types are involved in cell signaling networks, and homeostatic regulatory mechanisms contribute to the control of ion channel expression. Profiling of global gene expression using microarray technology has recently provided novel insights into the molecular mechanisms underlying the homeostatic and pathological control of ion channel expression. It has demonstrated that the dysregulation of ion channel expression is associated with the pathogenesis of neural, cardiovascular, and immune diseases as well as cancers. In addition to the transcriptional, translational, and post-translational regulation of ion channels, potentially important evidence on the mechanisms controlling ion channel expression has recently been accumulated. The regulation of alternative pre-mRNA splicing is therefore a novel therapeutic strategy for the treatment of dominant-negative splicing disorders. Epigenetic modification plays a key role in various pathological conditions through the regulation of pluripotency genes. Inhibitors of pre-mRNA splicing and histone deacetyalase/methyltransferase have potential as potent therapeutic drugs for cancers and autoimmune and inflammatory diseases. Moreover, membrane-anchoring proteins, lysosomal and proteasomal degradation-related molecules, auxiliary subunits, and pharmacological agents alter the protein folding, membrane trafficking, and post-translational modifications of ion channels, and are linked to expression-defect channelopathies. In this review, we focused on recent insights into the transcriptional, spliceosomal, epigenetic, and proteasomal regulation of ion channel expression: Ca(2+) channels (TRPC/TRPV/TRPM/TRPA/Orai), K(+) channels (voltage-gated, KV/Ca(2+)-activated, KCa/two-pore domain, K2P/inward-rectifier, Kir), and Ca(2+)-activated Cl(-) channels (TMEM16A/TMEM16B). Furthermore, this review highlights expression of these ion channels in expression-defect channelopathies.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan.
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Göb E, Bittner S, Bobak N, Kraft P, Göbel K, Langhauser F, Homola GA, Brede M, Budde T, Meuth SG, Kleinschnitz C. The two-pore domain potassium channel KCNK5 deteriorates outcome in ischemic neurodegeneration. Pflugers Arch 2014; 467:973-87. [PMID: 25315980 DOI: 10.1007/s00424-014-1626-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 09/29/2014] [Accepted: 10/01/2014] [Indexed: 01/05/2023]
Abstract
Potassium channels can fulfill both beneficial and detrimental roles in neuronal damage during ischemic stroke. Earlier studies have characterized a neuroprotective role of the two-pore domain potassium channels KCNK2 (TREK1) and KCNK3 (TASK1). Protective neuronal hyperpolarization and prevention of intracellular Ca(2+) overload and glutamate excitotoxicity were suggested to be the underlying mechanisms. We here identify an unexpected role for the related KCNK5 channel in a mouse model of transient middle cerebral artery occlusion (tMCAO). KCNK5 is strongly upregulated on neurons upon cerebral ischemia, where it is most likely involved in the induction of neuronal apoptosis. Hypoxic conditions elevated neuronal expression levels of KCNK5 in acute brain slices and primary isolated neuronal cell cultures. In agreement, KCNK5 knockout mice had significantly reduced infarct volumes and improved neurologic function 24 h after 60 min of tMCAO and this protective effect was preserved at later stages of infarct development. KCNK5 deficiency resulted in a significantly reduced number of apoptotic neurons, a downregulation of pro-apoptotic and upregulation of anti-apoptotic factors. Results of adoptive transfer experiments of wild-type and Kcnk5 (-/-) immune cells into Rag1 (-/-) mice prior to tMCAO exclude a major role of KCNK5 in poststroke inflammatory reactions. In summary, KCNK5 expression is induced on neurons under ischemic conditions where it most likely exerts pro-apoptotic effects. Hence, pharmacological blockade of KCNK5 might have therapeutic potential in preventing ischemic neurodegeneration.
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Affiliation(s)
- Eva Göb
- Department of Neurology, University Clinics Würzburg, Würzburg, Germany
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Shin DH, Lin H, Zheng H, Kim KS, Kim JY, Chun YS, Park JW, Nam JH, Kim WK, Zhang YH, Kim SJ. HIF-1α-mediated upregulation of TASK-2 K⁺ channels augments Ca²⁺ signaling in mouse B cells under hypoxia. THE JOURNAL OF IMMUNOLOGY 2014; 193:4924-33. [PMID: 25305321 DOI: 10.4049/jimmunol.1301829] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The general consensus is that immune cells are exposed to physiological hypoxia in vivo (PhyO2, 2-5% P(O2)). However, functional studies of B cells in hypoxic conditions are sparse. Recently, we reported the expression in mouse B cells of TASK-2, a member of pH-sensitive two-pore domain K(+) channels with background activity. In this study, we investigated the response of K(+) channels to sustained PhyO2 (sustained hypoxia [SH], 3% P(O2) for 24 h) in WEHI-231 mouse B cells. SH induced voltage-independent background K(+) conductance (SH-K(bg)) and hyperpolarized the membrane potential. The pH sensitivity and the single-channel conductance of SH-K(bg) were consistent with those of TASK-2. Immunoblotting assay results showed that SH significantly increased plasma membrane expressions of TASK-2. Conversely, SH failed to induce any current following small interfering (si)TASK-2 transfection. Similar hypoxic upregulation of TASK-2 was also observed in splenic primary B cells. Mechanistically, upregulation of TASK-2 by SH was prevented by si hypoxia-inducible factor-1α (HIF-1α) transfection or by YC-1, a pharmacological HIF-1α inhibitor. In addition, TASK-2 current was increased in WEHI-231 cells overexpressed with O2-resistant HIF-1α. Importantly, [Ca(2+)]c increment in response to BCR stimulation was significantly higher in SH-exposed B cells, which was abolished by high K(+)-induced depolarization or by siTASK-2 transfection. The data demonstrate that TASK-2 is upregulated under hypoxia via HIF-1α-dependent manner in B cells. This is functionally important in maintaining the negative membrane potential and providing electrical driving force to control Ca(2+) influx.
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Affiliation(s)
- Dong Hoon Shin
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Division of Natural Medical Sciences, College of Health Science, Chosun University, Gwangju 501-759, Republic of Korea
| | - Haiyue Lin
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Haifeng Zheng
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Kyung Su Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Jin Young Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Yang Sook Chun
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Jong Wan Park
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Pharmacology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; and
| | - Joo Hyun Nam
- Channelopathy Research Center, Dongguk University College of Medicine, Goyang 410-773, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center, Dongguk University College of Medicine, Goyang 410-773, Republic of Korea
| | - Yin Hua Zhang
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea;
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Abstract
By definition central respiratory chemoreceptors (CRCs) are cells that are sensitive to changes in brain PCO(2) or pH and contribute to the stimulation of breathing elicited by hypercapnia or metabolic acidosis. CO(2) most likely works by lowering pH. The pertinent proton receptors have not been identified and may be ion channels. CRCs are probably neurons but may also include acid-sensitive glia and vascular cells that communicate with neurons via paracrine mechanisms. Retrotrapezoid nucleus (RTN) neurons are the most completely characterized CRCs. Their high sensitivity to CO(2) in vivo presumably relies on their intrinsic acid sensitivity, excitatory inputs from the carotid bodies and brain regions such as raphe and hypothalamus, and facilitating influences from neighboring astrocytes. RTN neurons are necessary for the respiratory network to respond to CO(2) during the perinatal period and under anesthesia. In conscious adults, RTN neurons contribute to an unknown degree to the pH-dependent regulation of breathing rate, inspiratory, and expiratory activity. The abnormal prenatal development of RTN neurons probably contributes to the congenital central hypoventilation syndrome. Other CRCs presumably exist, but the supportive evidence is less complete. The proposed locations of these CRCs are the medullary raphe, the nucleus tractus solitarius, the ventrolateral medulla, the fastigial nucleus, and the hypothalamus. Several wake-promoting systems (serotonergic and catecholaminergic neurons, orexinergic neurons) are also putative CRCs. Their contribution to central respiratory chemoreception may be behavior dependent or vary according to the state of vigilance.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
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Genetic networks of cooperative redox regulation of osteopontin. Matrix Biol 2008; 27:462-74. [PMID: 18378437 DOI: 10.1016/j.matbio.2008.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 01/25/2008] [Accepted: 01/30/2008] [Indexed: 10/22/2022]
Abstract
Osteopontin is a primary cytokine and matrix-associated protein involved in medial thickening and neointima formation. Osteopontin binds integrin receptors, activates cell migration and matrix metalloproteinases, and mediates arteriosclerotic lesion formation and vessel calcification. To understand the complex biology of osteopontin, computational methodology was employed to identify sets of genes whose transcriptional states were predictive of osteopontin gene expression based on the transcriptional states of 12,400 genes and ESTs across 235 independent Affymetrix Murine Genome Array MG_U74Av2 hybridizations. Arginase [GenBank: U51805] and Mac-2 antigen [GenBank: X16834] were identified as primary attractors within the gene-gene interaction network of osteopontin. Resolution of molecular interactions among these genes indicated that the majority of predictor genes could be linked through redox regulated transcription by nuclear factor kappa-B and transforming growth factor beta inducible early gene 1 regulatory elements. Subsequent molecular analyses established redox sensitivity of a 200 bp region within the 5' UTR of opn promoter and implicated nuclear factor kappa-B and transforming growth factor beta inducible early gene 1 cis-acting elements in the regulation of osteopontin.
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Lotshaw DP. Biophysical, pharmacological, and functional characteristics of cloned and native mammalian two-pore domain K+ channels. Cell Biochem Biophys 2007; 47:209-56. [PMID: 17652773 DOI: 10.1007/s12013-007-0007-8] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 12/12/2022]
Abstract
The mammalian family of two-pore domain K+ (K2P) channel proteins are encoded by 15 KCNK genes and subdivided into six subfamilies on the basis of sequence similarities: TWIK, TREK, TASK, TALK, THIK, and TRESK. K2P channels are expressed in cells throughout the body and have been implicated in diverse cellular functions including maintenance of the resting potential and regulation of excitability, sensory transduction, ion transport, and cell volume regulation, as well as metabolic regulation and apoptosis. In recent years K2P channel isoforms have been identified as important targets of several widely employed drugs, including: general anesthetics, local anesthetics, neuroprotectants, and anti-depressants. An important goal of future studies will be to identify the basis of drug actions and channel isoform selectivity. This goal will be facilitated by characterization of native K2P channel isoforms, their pharmacological properties and tissue-specific expression patterns. To this end the present review examines the biophysical, pharmacological, and functional characteristics of cloned mammalian K2P channels and compares this information with the limited data available for native K2P channels in order to determine criteria which may be useful in identifying ionic currents mediated by native channel isoforms and investigating their pharmacological and functional characteristics.
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Affiliation(s)
- David P Lotshaw
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
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