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Lee JY, Ryu HS, Yoon SS, Kim EH, Yoon SW. Extracellular-to-Intracellular Fluid Volume Ratio as a Prognostic Factor for Survival in Patients With Metastatic Cancer. Integr Cancer Ther 2019; 18:1534735419847285. [PMID: 31043080 PMCID: PMC6498769 DOI: 10.1177/1534735419847285] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Purpose: This study aimed to investigate whether the
extracellular-to-intracellular fluid volume (E/I) ratio can predict survival in
patients with metastatic cancer. Methods: Clinical data were
collected from April 2016 to March 2018. Patients aged ≥19 years with metastatic
solid tumor were eligible. Bioimpedance analysis was used to assess body fluid
distribution and the E/I ratio. Clinical characteristics, including laboratory
test results and nutrition status according to the E/I ratio, were analyzed. Cox
proportional hazards models and Kaplan-Meier analysis were used to identify risk
factors for mortality. Results: In total, 87 patients were included
in the study. The 87 patients were divided into 2 groups according to the median
E/I ratio: a high E/I group (E/I ratio ≥1.0, n = 43) and a low E/I group (E/I
ratio <1.0, n = 44). Poor performance status, fluid retention, malnutrition,
elevation of C-reactive protein levels, and decreases in hemoglobin, albumin,
and protein levels were significantly associated with the high E/I group. The
median overall survival time was 1.6 and 12.5 months in the high E/I and low E/I
groups, respectively (P < .001). In the multivariate
analysis, poor performance status, leukocytosis, fluid retention, and E/I ratio
were independent prognostic factors, and the E/I ratio was the strongest
prognostic factor predicting overall survival (hazard ratio = 3.49, 95%
confidence interval = 1.75-6.96, P < .001).
Conclusions: The E/I ratio can predict survival time in
patients with metastatic cancer. More rigorous research is required to confirm
this result.
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Affiliation(s)
- Jee Young Lee
- Kyung Hee University Hospital at
Gangdong, Gangdonggu, Seoul, Republic of Korea
| | - Han Sung Ryu
- Kyung Hee University Hospital at
Gangdong, Gangdonggu, Seoul, Republic of Korea
| | - Sung Soo Yoon
- Kyung Hee University Hospital at
Gangdong, Gangdonggu, Seoul, Republic of Korea
| | - Eun Hye Kim
- Kyung Hee University Hospital at
Gangdong, Gangdonggu, Seoul, Republic of Korea
| | - Seong Woo Yoon
- Kyung Hee University Hospital at
Gangdong, Gangdonggu, Seoul, Republic of Korea
- Seong Woo Yoon, Department of Internal
Medicine, Korean Medicine Cancer Center, Kyung Hee University Hospital at
Gangdong, Dongnamro 892, Gangdonggu, Seoul 134-727, Republic of Korea.
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Głąbska D, Cackowska K, Guzek D. Comparison of the Body Composition of Caucasian Young Normal Body Mass Women, Measured in the Follicular Phase, Depending on the Carbohydrate Diet Level. ACTA ACUST UNITED AC 2018; 54:medicina54060104. [PMID: 30563184 PMCID: PMC6306892 DOI: 10.3390/medicina54060104] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/14/2018] [Accepted: 12/02/2018] [Indexed: 12/28/2022]
Abstract
Background and objectives: Some publications indicate the possibility of the influence of meal nutritional value on results of bioelectrical impedance, and of the relation between the long-term carbohydrate intake and body composition. The aim of the presented study was to evaluate the influence of long-term intake of carbohydrates on body composition results assessed using the bioelectrical impedance of Caucasian young women with normal body mass, who were in the follicular phase of their menstrual cycle. Materials and Methods: Body composition was assessed in 100 women (18–30 years), according to strict rules, to minimize the influence of disturbing factors and by using two types of bioelectrical impedance device of the same operator to eliminate the influence of measurement (BIA 101/SC and BIA 101/ASE by Akern Srl, Firenze, Italy with the Bodygram 1.31 software and its equations by Akern Srl, Firenze, Italy). The analysis included validation of reproducibility of body composition assessment (fat, fat-free, body cell and muscle mass, water, extracellular water, and intracellular water content), and comparison of body composition for groups characterized by carbohydrate content <50% (n = 55) and >50% of the energy value of the diet (n = 45). Results: Analysis conducted using Bland–Altman method, analysis of correlation, analysis of quartile distribution, and weighted κ statistic revealed a positively validated reproducibility, but extracellular water associations were the weakest. Depending on the device, participants characterized by higher carbohydrate intake had significantly higher intracellular water content (p = 0.0448), or close to significantly higher (p = 0.0851) than those characterized by lower carbohydrate intake, whose extracellular water content was close to significantly lower (p = 0.0638) or did not differ. Conclusions: The long-term, moderately reduced, carbohydrate intake may cause the shift of intracellular water to the extracellular space and, as a result, influence the body composition results.
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Affiliation(s)
- Dominika Głąbska
- Department of Dietetics, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences (WULS-SGGW), 159c Nowoursynowska Str., 02-776 Warsaw, Poland.
| | - Karolina Cackowska
- Department of Dietetics, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences (WULS-SGGW), 159c Nowoursynowska Str., 02-776 Warsaw, Poland.
| | - Dominika Guzek
- Department of Organization and Consumption Economics, Faculty of Human Nutrition and Consumer Sciences, Warsaw University of Life Sciences (WULS-SGGW), 159c Nowoursynowska Str., 02-776 Warsaw, Poland.
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İlhan TT, Uçar MG, Pekin AT, Yılmaz SA, Kerimoğlu ÖS, Çelik Ç. Does lymphadenectomy have influence on postoperative body fluid distribution? Eur J Obstet Gynecol Reprod Biol 2017; 212:182-185. [PMID: 28236490 DOI: 10.1016/j.ejogrb.2017.02.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/05/2017] [Accepted: 02/11/2017] [Indexed: 12/31/2022]
Abstract
OBJECTIVE We compared the fluid volume parameters in women undergoing gynaecological surgery for benign and malignant conditions before and after surgery using bioelectrical impedance vectors. STUDY DESIGN A total of 181 patients were enrolled. In all, 89 patients had surgery for benign conditions and 92 patients underwent oncological procedures, including lymph node dissection, for malignant diseases. Bioelectrical impedance analysis (BIA) parameters were measured on the day of hospitalisation before any treatment and at 24h and 1 month after the surgical intervention. The BIA parameters measured included extracellular water (ECW), intracellular water (ICW), and total body water (TBW). RESULTS TBW increased significantly 1 month after surgery in all cases (p<0,05 in both group). ECW was significantly higher (p<0.05) and ICW was significantly lower (p<0,05) in the malignant group than the benign group. CONCLUSION Radical gynaecological surgeries, including lymph node dissection, have a greater effect on body water distribution than surgeries performed for benign conditions.
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Affiliation(s)
| | - Mustafa Gazi Uçar
- Selçuk University, Faculty of Medicine, Department of Obstetrics and Gynecology, 42075, Konya, Turkey.
| | - Aybike Tazegül Pekin
- Selçuk University, Faculty of Medicine, Department of Obstetrics and Gynecology, 42075, Konya, Turkey.
| | - Setenay Arzu Yılmaz
- Selçuk University, Faculty of Medicine, Department of Obstetrics and Gynecology, 42075, Konya, Turkey.
| | - Özlem Seçilmiş Kerimoğlu
- Selçuk University, Faculty of Medicine, Department of Obstetrics and Gynecology, 42075, Konya, Turkey.
| | - Çetin Çelik
- Selçuk University, Faculty of Medicine, Department of Obstetrics and Gynecology, Gynecologic Oncology Unit, 42075, Konya, Turkey.
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4
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Abstract
Body composition assessment has been used to evaluate clinical interventions in research trials, and has the potential to improve patient care in the clinical setting. Body cell mass (BCM) is an important indicator of nutrition status; however, its measurement in the clinic has been limited. BCM can be estimated by the measurement of intracellular water (ICW). The assessment of extracellular water (ECW) is also important because many clinical populations undergo alterations in fluid distribution, particularly individuals with wasting, those receiving dialysis, and obese individuals. Bioimpedance spectroscopy (BIS) is a unique bioimpedance approach that differs in underlying basis from the more readily recognized single-frequency bioelectrical impedance analysis (SF-BIA) in that it does not require the use of statistically derived, population-specific prediction equations. It has the potential advantage of not only measuring total body water (TBW), as does SF-BIA, but also offering the unique capacity to differentiate between ECW and ICW and, thus, to provide an estimate of BCM. This literature review was conducted to compare available BIS devices to multiple dilution for measuring fluid compartments or BCM in a number of populations. Variable results regarding the ability of BIS to measure absolute volumes, as well as the observation of wide limits of variation, make BIS problematic for individual assessment in the clinic, particularly in populations with abnormal fluid distribution or body geometry. BIS has been found to be more accurate for measuring changes in fluid volumes or BCM, particularly in post-surgical and human immunodeficiency virus (HIV)-infected individuals. It is certainly possible that population-specific adjustments may improve the accuracy of BIS for assessing individuals in the clinical setting; however, additional research and development is needed before the method can be accepted for routine clinical use.
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Affiliation(s)
- Carrie Earthman
- University of Minnesota, 225 Food Science and Nutrition, 1334 Eckles Ave., St. Paul, MN 55108, USA.
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Ali F, Wharton DA. Intracellular freezing in the infective juveniles of Steinernema feltiae: an entomopathogenic nematode. PLoS One 2014; 9:e94179. [PMID: 24769523 PMCID: PMC4000207 DOI: 10.1371/journal.pone.0094179] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 03/13/2014] [Indexed: 11/23/2022] Open
Abstract
Taking advantage of their optical transparency, we clearly observed the third stage infective juveniles (IJs) of Steinernema feltiae freezing under a cryo-stage microscope. The IJs froze when the water surrounding them froze at -2°C and below. However, they avoid inoculative freezing at -1°C, suggesting cryoprotective dehydration. Freezing was evident as a sudden darkening and cessation of IJs' movement. Freeze substitution and transmission electron microscopy confirmed that the IJs of S. feltiae freeze intracellularly. Ice crystals were found in every compartment of the body. IJs frozen at high sub-zero temperatures (-1 and -3°C) survived and had small ice crystals. Those frozen at -10°C had large ice crystals and did not survive. However, the pattern of ice formation was not well-controlled and individual nematodes frozen at -3°C had both small and large ice crystals. IJs frozen by plunging directly into liquid nitrogen had small ice crystals, but did not survive. This study thus presents the evidence that S. feltiae is only the second freeze tolerant animal, after the Antarctic nematode Panagrolaimus davidi, shown to withstand extensive intracellular freezing.
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Affiliation(s)
- Farman Ali
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - David A. Wharton
- Department of Zoology, University of Otago, Dunedin, New Zealand
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Kasuga J, Endoh K, Yoshiba M, Taido I, Arakawa K, Uemura M, Fujikawa S. Roles of cell walls and intracellular contents in supercooling capability of xylem parenchyma cells of boreal trees. Physiol Plant 2013; 148:25-35. [PMID: 22901079 DOI: 10.1111/j.1399-3054.2012.01678.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/23/2012] [Accepted: 06/12/2012] [Indexed: 05/20/2023]
Abstract
The supercooling capability of xylem parenchyma cells (XPCs) in boreal hardwood species differs depending not only on species, but also season. In this study, the roles of cell walls and intracellular contents in supercooling capability of XPCs were examined in three boreal hardwood species, Japanese beech, katsura tree and mulberry, whose supercooling capability differs largely depending on species and season. XPCs in these species harvested in winter and summer were treated by rapid freezing and thawing (RFT samples) or by RFT with further washing (RFTW samples) to remove intracellular contents from XPCs in order to examine the roles of cell walls in supercooling. RFT samples were also treated with glucose solution (RFTG samples) to examine roles of intracellular contents in supercooling. The supercooling capabilities of these samples were examined by differential thermal analysis after ultrastructural observation of XPCs by a cryo-scanning electron microscope to confirm effects of the above treatments. XPCs in RFTW samples showed a large reduction in supercooling capability to similar temperatures regardless of species or season. On the other hand, XPCs in RFTG samples showed a large increase in supercooling capability to similar temperatures regardless of species or season. These results indicate that although cell walls have an important role in maintenance of supercooling, change in supercooling capability of XPCs is induced by change in intracellular contents, but not by change in cell wall properties.
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Affiliation(s)
- Jun Kasuga
- Cryobiofrontier Research Center, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan.
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7
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Kumar S, Khosravi M, Massart A, Potluri M, Davenport A. Haemodiafiltration results in similar changes in intracellular water and extracellular water compared to cooled haemodialysis. Am J Nephrol 2013; 37:320-4. [PMID: 23548830 DOI: 10.1159/000349925] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2013] [Accepted: 02/13/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS Intradialytic hypotension is the most common complication of modern day haemodialysis (HD). Convective modalities, including haemodiafiltration (HDF) are reported to result in greater cardiovascular stability compared to standard HD, which has been suggested to be due to improved solute transport between compartments. We therefore investigated the effect of treatment on body water by bioimpedance. METHODS We measured the change in extracellular water (ECW) and intracellular water (ICW) in 263 outpatients attending for HD using cooled dialysate and 134 patients for HDF. RESULTS Patient cohorts were matched for demographics, dialysate composition, ultrafiltration rate, and session duration. The fall in systolic blood pressure following HD was -11.8 mm Hg (-25.3 to 2.3) and not different from that following HDF -12 mm Hg (-27 to 6). Similarly there were no differences in pretreatment serum sodium and dialysate sodium gradient [HD 1 mmol/l (-1 to 3) vs. HDF 2 mmol/l (1 to 4)], or change in serum sodium posttreatment [HD 0 mmol/l (-2 to 2) vs. HDF 1 mmol/l (-1 to 3)]. There were no differences in ICW or ECW pretreatment, and following treatment the reduction in ICW and ECW did not differ [ICW HD -3.5% (-5.7 to -1.8) vs. -4.1% (-6.0 to -1.7), ECW HD -7.1% (-9.4 to -4.7) vs. HDF -7.1% (-9.7 to -4.9)]. CONCLUSION We were unable to demonstrate any advantage for HDF over HD using cooled dialysate in terms of changes in blood pressure during a treatment session, or differences in the relative changes in ICW or ECW volumes.
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Affiliation(s)
- Sanjeev Kumar
- UCL Centre for Nephrology, Royal Free Hospital, University College London Medical School, London, UK
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Kay BP, Hsu CP, Lu JF, Sun YN, Bai S, Xin Y, D’Argenio DZ. Intracellular-signaling tumor-regression modeling of the pro-apoptotic receptor agonists dulanermin and conatumumab. J Pharmacokinet Pharmacodyn 2012; 39:577-90. [PMID: 22932917 PMCID: PMC3487388 DOI: 10.1007/s10928-012-9269-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 08/14/2012] [Indexed: 11/29/2022]
Abstract
Dulanermin (rhApo2L/TRAIL) and conatumumab bind to transmembrane death receptors and trigger the extrinsic cellular apoptotic pathway through a caspase-signaling cascade resulting in cell death. Tumor size time series data from rodent tumor xenograft (COLO205) studies following administration of either of these two pro-apoptotic receptor agonists (PARAs) were combined to develop a intracellular-signaling tumor-regression model that includes two levels of signaling: upstream signals unique to each compound (representing initiator caspases), and a common downstream apoptosis signal (representing executioner caspases) shared by the two agents. Pharmacokinetic (PK) models for each drug were developed based on plasma concentration data following intravenous and/or intraperitoneal administration of the compounds and were used in the subsequent intracellular-signaling tumor-regression modeling. A model relating the PK of the two PARAs to their respective and common downstream signals, and to the resulting tumor burden was developed using mouse xenograft tumor size measurements from 448 experiments that included a wide range of dose sizes and dosing schedules. Incorporation of a pro-survival signal--consistent with the hypothesis that PARAs may also result in the upregulation of pro-survival factors that can lead to a reduction in effectiveness of PARAs with treatment--resulted in improved predictions of tumor volume data, especially for data from the long-term dosing experiments.
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Affiliation(s)
- Brittany P. Kay
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Cheng-Pang Hsu
- Quantitative Pharmacology, PKDM, Amgen, Thousand Oaks, CA, USA
| | - Jian-Feng Lu
- Quantitative Pharmacology, PKDM, Amgen, Thousand Oaks, CA, USA
| | - Yu-Nien Sun
- Quantitative Pharmacology, PKDM, Amgen, Thousand Oaks, CA, USA
| | - Shuang Bai
- Clinical Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | - Yan Xin
- Clinical Pharmacology, Genentech Inc, South San Francisco, CA, USA
| | - David Z. D’Argenio
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA,
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9
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Bulatov RD. [Use of integral two-frequency impedanciometry in clinical monitoring in patients with acute destructive pancreatitis]. Anesteziol Reanimatol 2012:59-62. [PMID: 22993928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The paper gives the results of studying the body water compartments and impedance parameters in 69 patients with acute destructive pancreatitis during postoperative period, by means of non-invasive integral two-frequency impedancometry. Progressing extracellular hyperhydratation and decreased total electrical impedance of body tissue accompanied by increased number of general and intraabdominal complications, mortality, that determine the prognostic significance of these criteria.
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Rattay F, Paredes L, Leao R. Strength-duration relationship for intra- versus extracellular stimulation with microelectrodes. Neuroscience 2012; 214:1-13. [PMID: 22516015 PMCID: PMC3401985 DOI: 10.1016/j.neuroscience.2012.04.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/06/2012] [Accepted: 04/05/2012] [Indexed: 12/04/2022]
Abstract
Chronaxie, a historically introduced excitability time parameter for electrical stimulation, has been assumed to be closely related to the time constant of the cell membrane. Therefore, it is perplexing that significantly larger chronaxies have been found for intracellular than for extracellular stimulation. Using compartmental model analysis, this controversy is explained on the basis that extracellular stimulation also generates hyperpolarized regions of the cell membrane hindering a steady excitation as seen in the intracellular case. The largest inside/outside chronaxie ratio for microelectrode stimulation is found in close vicinity of the cell. In the case of monophasic cathodic stimulation, the length of the primarily excited zone which is situated between the hyperpolarized regions increases with electrode–cell distance. For distant electrodes this results in an excitation process comparable to the temporal behavior of intracellular stimulation. Chronaxie also varies along the neural axis, being small for electrode positions at the nodes of Ranvier and axon initial segment and larger at the soma and dendrites. As spike initiation site can change for short and long pulses, in some cases strength–duration curves have a bimodal shape, and thus, they deviate from a classical monotonic curve as described by the formulas of Lapicque or Weiss.
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Affiliation(s)
- F. Rattay
- Institute for Analysis and Scientific Computing, Vienna University of Technology, A-1040 Vienna, Austria
- Corresponding author. Tel: +43-1-58801-10114.
| | - L.P. Paredes
- Institute for Analysis and Scientific Computing, Vienna University of Technology, A-1040 Vienna, Austria
| | - R.N. Leao
- Neurodynamics Laboratory, Department of Neuroscience, Uppsala University, Uppsala, Sweden
- Brain Institute, Federal University of Rio Grande do Norte, Natal-RN, Brazil
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Warren DE, Bickler PE, Clark JP, Gregersen M, Brosnan H, McKleroy W, Gabatto P. Hypothermia and rewarming injury in hippocampal neurons involve intracellular Ca2+ and glutamate excitotoxicity. Neuroscience 2012; 207:316-25. [PMID: 22265728 DOI: 10.1016/j.neuroscience.2011.12.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 11/18/2022]
Abstract
This study examines the causes of hypothermia and rewarming injury in CA1, CA3, and dentate neurons in rat hippocampal slice cultures. Neuronal death, assessed with propidium iodide or Sytox fluorescence, Fluoro-Jade labeling, and Cresyl Violet staining, depended on the severity and duration of hypothermia. More than 6 h at temperatures less than 12 °C followed by rewarming to 37 °C (profound hypothermia and rewarming, PH/RW) caused swelling and death in large number of neurons in CA1, CA3, and dentate. During PH, [ATP] decreased and [Ca(2+)](I) and extracellular [glutamate] increased, with neuron rupture and nuclear condensation following RW. The data support the hypothesis that neuronal death from PH/RW is excitotoxic, due to ATP loss, glutamate receptor activation and Ca(2+) influx. We found that antagonism of N-methyl-D-aspartate (NMDA) receptors, but not 2-amino-3-(5-methyl-3-oxo-1,2- oxazol-4-yl) propanoic acid or metabotropic glutamate receptors, decreased neuron death and prevented increases in [Ca(2+)](I) caused by PH/RW. Chelating extracellular Ca(2+) decreased PH/RW injury, but inhibiting L- and T-type voltage-gated Ca(2+) channels, K+ channels, Ca(2+) release from the endoplasmic reticulum, and reverse Na(+)/Ca(2+) exchange did not affect the Ca(2+) changes or cell death. We conclude that the mechanism of PH/RW neuronal injury in hippocampal slices primarily involves intracellular Ca(2+) accumulation mediated by NMDA receptors that activates necrotic, but not apoptotic processes.
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Affiliation(s)
- D E Warren
- Department of Anesthesia and Perioperative Care, Parnassus Avenue, University of California, San Francisco, CA 94143-0542, USA
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12
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Cai B, Gong D, Chen N, Li J, Wang G, Lu Y, Yang B. The negative inotropic effects of homocysteine were prevented by matrine via the regulating intracellular calcium level. Int J Cardiol 2011; 150:113-5. [PMID: 21596451 DOI: 10.1016/j.ijcard.2011.04.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/25/2011] [Indexed: 11/29/2022]
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13
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Zhuravleva NA. [Cell as an integral water-dependent system in onthogenesis]. Adv Gerontol 2011; 24:570-586. [PMID: 22550864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The study proposes a model of plant cell as an integral physical and physical-chemical water-dependent system of maximum structural complexity and complete combination of functions. The framework of this model allows analyzing any cell of simpler organization in any degree of reduction, animal cell included. The model justifies priority in the establishment of internal and functional (turgor) cell pressure of its cytoplasmatic solution high-molecular component along the chain: genome-->protein (quality and quantity)-->functional(turgor) pressure-->cell internal pressure-->water content in cell, gradual decrease of which results in cell death.
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14
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Dickson HM, Zurawski J, Zhang H, Turner DL, Vojtek AB. POSH is an intracellular signal transducer for the axon outgrowth inhibitor Nogo66. J Neurosci 2010; 30:13319-25. [PMID: 20926658 PMCID: PMC2963859 DOI: 10.1523/jneurosci.1324-10.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 07/22/2010] [Accepted: 08/07/2010] [Indexed: 01/31/2023] Open
Abstract
Myelin-derived inhibitors limit axon outgrowth and plasticity during development and in the adult mammalian CNS. Nogo66, a functional domain of the myelin-derived inhibitor NogoA, signals through the PirB receptor to inhibit axon outgrowth. The signaling pathway mobilized by Nogo66 engagement of PirB is not well understood. We identify a critical role for the scaffold protein Plenty of SH3s (POSH) in relaying process outgrowth inhibition downstream of Nogo66 and PirB. Blocking the function of POSH, or two POSH-associated proteins, leucine zipper kinase (LZK) and Shroom3, with RNAi in cortical neurons leads to release from myelin and Nogo66 inhibition. We also observed autocrine inhibition of process outgrowth by NogoA, and suppression analysis with the POSH-associated kinase LZK demonstrated that LZK operates downstream of NogoA and PirB in a POSH-dependent manner. In addition, cerebellar granule neurons with an RNAi-mediated knockdown in POSH function were refractory to the inhibitory action of Nogo66, indicating that a POSH-dependent mechanism operates to inhibit axon outgrowth in different types of CNS neurons. These studies delineate an intracellular signaling pathway for process outgrowth inhibition by Nogo66, comprised of NogoA, PirB, POSH, LZK, and Shroom3, and implicate the POSH complex as a potential therapeutic target to enhance axon outgrowth and plasticity in the injured CNS.
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Affiliation(s)
| | | | - Huanqing Zhang
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109
| | - David L. Turner
- Department of Biological Chemistry and
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109
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15
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Lencesova L, Sirova M, Csaderova L, Laukova M, Sulova Z, Kvetnansky R, Krizanova O. Changes and role of adrenoceptors in PC12 cells after phenylephrine administration and apoptosis induction. Neurochem Int 2010; 57:884-92. [PMID: 20888879 DOI: 10.1016/j.neuint.2010.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 09/21/2010] [Accepted: 09/24/2010] [Indexed: 11/18/2022]
Abstract
The present study addresses the hypothesis that adrenergic regulation modulates the effect of apoptosis. Therefore we studied, whether α1-adrenergic receptor's agonist phenylephrine (PE) can affect or induce apoptosis in rat pheochromocytoma (PC12) cells. We have shown that PE treatment did not increase level of the apoptosis, or level of the caspase 3 mRNA. When apoptosis was induced in the presence of PE, caspase 3 mRNA was significantly increased, while the percentage of apoptotic cells remained unchanged compared to apoptotic group without PE. During this process, α1D-, β2- and β3-adrenergic receptors (ARs) were upregulated. Since all these three types of ARs are differently localized in the cell, we assume that mutual communication of all three ARs is crucial to participate in this signaling and during development of apoptosis, some of these systems might translocate. Another important system in handling noradrenaline during apoptosis might be noradrenaline transporter (NET), since it was downregulated in apoptotic cells treated with PE, compared to untreated apoptotic cells. However, precise mechanism of mutual communication among all these systems remains to be elucidated.
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Affiliation(s)
- Lubomira Lencesova
- Institute of Molecular Physiology and Genetics, Center of Excellence for Cardiovascular Research, Slovak Academy of Sciences, Vlarska 5, 833 34 Bratislava, Slovak Republic
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16
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Abstract
Intracellular transmission of information via chemical and transcriptional networks is thwarted by a physical limitation: The finite copy number of the constituent chemical species introduces unavoidable intrinsic noise. Here we solve for the complete probabilistic description of the intrinsically noisy response to an oscillatory driving signal. We derive and numerically verify a number of simple scaling laws. Unlike in the case of measuring a static quantity, response to an oscillatory signal can exhibit a resonant frequency which maximizes information transmission. Furthermore, we show that the optimal regulatory design is dependent on biophysical constraints (i.e., the allowed copy number and response time). The resulting phase diagram illustrates under what conditions threshold regulation outperforms linear regulation.
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Affiliation(s)
- Andrew Mugler
- Department of Physics, Columbia University, New York, New York 10027, USA
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17
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Young J, Mitran S. A numerical model of cellular blebbing: a volume-conserving, fluid-structure interaction model of the entire cell. J Biomech 2010; 43:210-20. [PMID: 19875121 PMCID: PMC2813352 DOI: 10.1016/j.jbiomech.2009.09.025] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 09/02/2009] [Accepted: 09/02/2009] [Indexed: 11/18/2022]
Abstract
In animal cells, blebs are smooth, quasi-hemispherical protrusions of the plasma membrane that form when a section of the membrane detaches from the underlying actin cytoskeleton and is inflated by flowing cytosol. The mechanics behind this common cellular activity are not yet clear. As a first step in the development of a full computational framework, we present a numerical model of overall cell behavior based upon the interaction between a background Newtonian-fluid cytosol and elastic structures modeling the membrane and filaments. The detailed micromechanics of the cytoskeletal network are the subject of future work. Here, the myosin-driven contraction of the actin network is modeled through stressed elastic filaments. Quantitative models of cytoskeletal micromechanics and biochemistry require accurate estimates of local stress and flow conditions. The main contribution of this paper is the development of a computationally efficient fluid-structure interaction model based on operator splitting, to furnish this data. Cytosol volume conservation (as supported by experimental evidence) is enforced through an intermediate energy minimization step. Realistic bleb formation and retraction is observed from this model, offering an alternative formulation to positing complex continuum behavior of the cytoplasm (e.g. poroelastic model of Charras et al., 2008).
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Affiliation(s)
- Jennifer Young
- Department of Mathematics, University of North Carolina at Chapel Hill, Phillips Hall, Chapel Hill, NC 27599, USA.
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18
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Vander Griend DJ, D’Antonio J, Gurel B, Antony L, DeMarzo AM, Isaacs JT. Cell-autonomous intracellular androgen receptor signaling drives the growth of human prostate cancer initiating cells. Prostate 2010; 70:90-9. [PMID: 19790235 PMCID: PMC2788041 DOI: 10.1002/pros.21043] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The lethality of prostate cancer is due to the continuous growth of cancer initiating cells (CICs) which are often stimulated by androgen receptor (AR) signaling. However, the underlying molecular mechanism(s) for such AR-mediated growth stimulation are not fully understood. Such mechanisms may involve cancer cell-dependent induction of tumor stromal cells to produce paracrine growth factors or could involve cancer cell autonomous autocrine and/or intracellular AR signaling pathways. METHODS We utilized clinical samples, animal models and a series of AR-positive human prostate cancer cell lines to evaluate AR-mediated growth stimulation of prostate CICs. RESULTS The present studies document that stromal AR expression is not required for prostate cancer growth, since tumor stroma surrounding AR-positive human prostate cancer metastases (N = 127) are characteristically AR-negative. This lack of a requirement for AR expression in tumor stromal cells is also documented by the fact that human AR-positive prostate cancer cells grow equally well when xenografted in wild-type versus AR-null nude mice. AR-dependent growth stimulation was documented to involve secretion, extracellular binding, and signaling by autocrine growth factors. Orthotopic xenograft animal studies documented that the cellautonomous autocrine growth factors which stimulate prostate CIC growth are not the andromedins secreted by normal prostate stromal cells. Such cell autonomous and extracellular autocrine signaling is necessary but not sufficient for the optimal growth of prostate CICs based upon the response to anti-androgen plus/or minus preconditioned media. CONCLUSIONS AR-induced growth stimulation of human prostate CICs requires AR-dependent intracellular pathways. The identification of such AR-dependent intracellular pathways offers new leads for the development of effective therapies for prostate cancer.
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Affiliation(s)
- Donald J. Vander Griend
- Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jason D’Antonio
- Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bora Gurel
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Lizamma Antony
- Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Angelo M. DeMarzo
- The Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - John T. Isaacs
- Chemical Therapeutics Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University School of Medicine, Baltimore, Maryland
- The Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland
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20
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Abstract
Astrocytes release peptide and nonpeptide transmitters that influence neuronal development, function, and plasticity. However, the molecular components of the astroglial secretory pathways in vivo are largely unknown. Here, we analyze in astrocytes the production, expression regulation, trafficking, and release of secretogranin III (SgIII), a member of the multifunctional granin family. We show that astroglial cells in culture synthesize and release a nonprocessed form of SgIII. In vivo studies show that many neuronal populations produce and transport SgIII. In particular, the highest SgIII expression in the cerebral cortex in vivo is present in astroglial cells. Both SgIII protein and mRNA are abundantly detected in cortical astrocytes and in Bergmann glial cells. Moreover, the levels of SgIII mRNA and protein in reactive astrocytes, induced by perforating injury increase dramatically. These results implicate SgIII in the astrocyte secretory pathway in vivo and show that its expression is finely regulated during glial activation. The robust expression of SgIII in astrocytes and its regulation in the injured brain suggest both intracellular and extracellular roles for this glial granin in the physiology and repair/damage of neuronal circuits.
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Affiliation(s)
- Sonia Paco
- Department of Cell Biology, University of Barcelona, Barcelona, Spain
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21
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Abstract
RNAi is a powerful technology for analyzing gene function in human cells. However, its utility can be compromised by inadequate knockdown of the target mRNA or by interpretation of effects without rigorous controls. We review lentiviral vector-based methods that enable transient or stable knockdowns to trace mRNA levels in human CD4+ T cell lines and other targets. Critical controls are reviewed, including rescue of the pre-knockdown phenotype by re-expression of the targeted gene. The time from thinking about a potential knockdown target to analysis of phenotypes can be as short as a few weeks.
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Affiliation(s)
- Tanner Miest
- Department of Molecular Medicine, Mayo Clinic College of Medicine, Guggenheim 1811A, 200 First Street SW, Rochester, MN 55905, USA
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22
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Abstract
Weak-acid, 31P-nuclear magnetic resonance (NMR) and microelectrode techniques for measuring intracellular pH (pHi) are compared by demonstration of their use in rat liver. The ultimate test of suitability of these methods is the confidence with which they can be used to clarify aspects of metabolic regulation, translocation of substances across biological membranes, and the control of cell pH itself. Though resting pHi in perfused liver is fairly similar with all three techniques, substantial quantitative differences between values obtained with 31P NMR and microelectrodes are revealed after addition of fructose to the perfused liver preparation. The use and limitations of weak-acid methods in determining the mechanism of inhibition of gluconeogenesis from lactate by acidosis and in determining the pH responsiveness of the lactate transporter in the hepatocyte plasma membrane are demonstrated. Microelectrode-derived values of pHi are probably referable to the bulk phase of the cytosol, whereas values from the other two methods are more complex in their interpretation. Microelectrode and NMR methods have the great advantage of being non-destructive, and continuous records may be obtained.
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Abstract
The motility of Amoeba proteus was examined using the technique of passive particle tracking microrheology, with the aid of newly developed particle tracking software, a fast digital camera, and an optical microscope. We tracked large numbers of endogeneous particles in the amoebae, which displayed subdiffusive motion at short timescales, corresponding to thermal motion in a viscoelastic medium, and superdiffusive motion at long timescales due to the convection of the cytoplasm. Subdiffusive motion was characterized by a rheological scaling exponent of 3/4 in the cortex, indicative of the semiflexible dynamics of the actin fibers. We observed shear-thinning in the flowing endoplasm, where exponents increased with increasing flow rate; i.e., the endoplasm became more fluid-like. The rheology of the cortex is found to be isotropic, reflecting an isotropic actin gel. A clear difference was seen between cortical and endoplasmic layers in terms of both viscoelasticity and flow velocity, where the profile of the latter is close to a Poiseuille flow for a Newtonian fluid.
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Affiliation(s)
- Salman S Rogers
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester M60 1QD, United Kingdom
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24
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Fein P, Chattopadhyay J, Paluch MM, Borawski C, Matza B, Avram MM. Enrollment fluid status is independently associated with long-term survival of peritoneal dialysis patients. Adv Perit Dial 2008; 24:79-83. [PMID: 18986007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Fluid overload is a common complication in peritoneal dialysis (PD) patients. The prognostic importance of enrollment fluid status in long-term PD patients remains to be investigated. The objective of the present study was to investigate the prognostic importance of enrollment fluid status in the long-term survival of PD patients. We enrolled 53 PD patients (mean age: 53 years) from November 2000 to February 2006. On enrollment, demographic, clinical, and biochemical data were recorded. Bioelectrical impedance analysis (BIA) was used to determine the fluid status of PD patients, including extracellular water (ECW), intracellular water (ICW), and total body water (TBW). Fluid status was corrected for body surface area (BSA): ECW-BSA, ICW-BSA, and TBW-BSA respectively. Patients were followed to January 2008. The ECW-BSA correlated negatively with albumin, a marker of nutrition (r = -0.53, p < 0.0001). The ICW/ECW ratio (r = 0.36, p = 0.018) correlated directly and the ECW/ TBW ratio (r = -0.36, p = 0.019) correlated negatively with creatinine. Patients who survived during the study period had a significantly lower ECW-BSA (8.29 L/m2 vs. 9.91 L/m2, p = 0.001) than did those who did not survive. Patients with enrollment ECW-BSA below 9 L/m2 had a significantly better 7-year cumulative survival (Kaplan-Meier) than did patients with a ECW-BSA of 9 L/m2 or more (p = 0.019). Using multivariate Cox regression analysis, adjusting for age, race, diabetes, human immunodeficiency virus (HIV) status, and months on dialysis at enrollment, ECW-BSA was a significant independent predictor of mortality (relative risk: 1.50; p = 0.03). In conclusion, ECW-BSA was a significant independent predictor of long-term survival in PD patients.
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Affiliation(s)
- Paul Fein
- Avram Division of Nephrology, Long Island College Hospital, Brooklyn, New York 11201, USA.
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25
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Bryantsev A, Kurchashova S, Golyshev S, Polyakov V, Wunderink H, Kanon B, Budagova K, Kabakov A, Kampinga H. Regulation of stress-induced intracellular sorting and chaperone function of Hsp27 (HspB1) in mammalian cells. Biochem J 2007; 407:407-17. [PMID: 17650072 PMCID: PMC2275061 DOI: 10.1042/bj20070195] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In vitro, small Hsps (heat-shock proteins) have been shown to have chaperone function capable of keeping unfolded proteins in a form competent for Hsp70-dependent refolding. However, this has never been confirmed in living mammalian cells. In the present study, we show that Hsp27 (HspB1) translocates into the nucleus upon heat shock, where it forms granules that co-localize with IGCs (interchromatin granule clusters). Although heat-induced changes in the oligomerization status of Hsp27 correlate with its phosphorylation and nuclear translocation, Hsp27 phosphorylation alone is not sufficient for effective nuclear translocation of HspB1. Using firefly luciferase as a heat-sensitive reporter protein, we demonstrate that HspB1 expression in HspB1-deficient fibroblasts enhances protein refolding after heat shock. The positive effect of HspB1 on refolding is completely diminished by overexpression of Bag-1 (Bcl-2-associated athanogene), the negative regulator of Hsp70, consistent with the idea of HspB1 being the substrate holder for Hsp70. Although HspB1 and luciferase both accumulate in nuclear granules after heat shock, our results suggest that this is not related to the refolding activity of HspB1. Rather, granular accumulation may reflect a situation of failed refolding where the substrate is stored for subsequent degradation. Consistently, we found 20S proteasomes concentrated in nuclear granules of HspB1 after heat shock. We conclude that HspB1 contributes to an increased chaperone capacity of cells by binding unfolded proteins that are hereby kept competent for refolding by Hsp70 or that are sorted to nuclear granules if such refolding fails.
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Affiliation(s)
- Anton L. Bryantsev
- *Department of Electron Microscopy, Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Svetlana Yu. Kurchashova
- *Department of Electron Microscopy, Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Sergey A. Golyshev
- *Department of Electron Microscopy, Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Vladimir Yu. Polyakov
- *Department of Electron Microscopy, Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Herman F. Wunderink
- †Department of Cell Biology, Section Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, 9791 AV, Groningen, The Netherlands
| | - Bart Kanon
- †Department of Cell Biology, Section Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, 9791 AV, Groningen, The Netherlands
| | - Karina R. Budagova
- ‡Department of Radiation Biochemistry, Medical Radiology Research Center, Obninsk, 249036, Russia
| | - Alexander E. Kabakov
- ‡Department of Radiation Biochemistry, Medical Radiology Research Center, Obninsk, 249036, Russia
| | - Harm H. Kampinga
- †Department of Cell Biology, Section Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, 9791 AV, Groningen, The Netherlands
- To whom correspondence should be addressed (email )
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26
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Granados MP, Salido GM, Pariente JA, Gonzáles A. Modulation of CCK-8-evoked intracellular Ca2+ waves by hydrogen peroxide in mouse pancreatic acinar cells. J Physiol Pharmacol 2007; 58:423-440. [PMID: 17928640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/03/2007] [Accepted: 04/30/2007] [Indexed: 05/25/2023]
Abstract
In the present study we have employed single cell imaging analysis to monitor the propagation of cholecystokinin-evoked Ca(2+) waves in mouse pancreatic acinar cells. Stimulation of cells with 1 nM CCK-8 led to an initial Ca(2+) release at the luminal cell pole and subsequent spreading of the Ca(2+) signal towards the basolateral membrane in the form of a Ca(2+) wave. Inhibition of sarcoendoplasmic reticulum Ca(2+)-ATPase (SERCA) activity by 1 microM thapsigargin, preincubation in the presence of 100 microM H(2)O(2) or inhibition of PKC with either 5 microM Ro31-8220 or 3 microM GF-109203-X all led to a faster propagation of CCK-8-induced Ca(2+) signals. The propagation of CCK-8-evoked Ca(2+) signals was slowed down by activation of PKC with 1 microM PMA, and preincubation of cells in the presence of H(2)O(2) counteracted the effect of PKC inhibition. The protonophore FCCP (100 nM) and the inhibitor of the mitochondrial Ca(2+)-uniporter Ru360 (10 microM) led to an increase in the propagation rate of CCK-8-evoked Ca(2+) waves. Finally, depolymerisation of actin cytoskeleton with cytochalasin D (10 microM) led to a faster propagation of CCK-8-evoked Ca(2+) signals. Stabilization of actin cytoskeleton with jasplakinolide (10 microM) did not induce significant changes on CCK-8-evoked Ca(2+) waves. Preincubation of cells in the presence of H(2)O(2) counteracted the effect of cytochalasin D on CCK-8-evoked Ca(2+) wave propagation. Our results suggest that spreading of cytosolic Ca(2+) waves evoked by CCK-8 can be modulated by low levels of oxidants acting on multiple Ca(2+)-handling mechanisms.
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Affiliation(s)
- M P Granados
- Department of Physiology (Cell Physiology Research Group), University of Extremadura. Cáceres, Spain
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27
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Christé G, Chahine M, Chevalier P, Pásek M. Changes in action potentials and intracellular ionic homeostasis in a ventricular cell model related to a persistent sodium current in SCN5A mutations underlying LQT3. Prog Biophys Mol Biol 2007; 96:281-93. [PMID: 17892895 DOI: 10.1016/j.pbiomolbio.2007.07.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In LQT3 patients, SCN5A mutations induce ultraslow inactivation of a small fraction of the hNav1.5 current, i.e. persistent Na+ current (IpNa). We explored the time course of effects of such a change on the intracellular ionic homeostasis in a model of guinea-pig cardiac ventricular cell [Pasek, M., Simurda, J., Orchard, C.H., Christé, G., 2007b. A model of the guinea-pig ventricular cardiomyocyte incorporating a transverse-axial tubular system. Prog. Biophys. Mol. Biol., this issue]. Sudden addition of IpNa prevented action potential (AP) repolarization when its conductance (gpNa) exceeded 0.12% of the maximal conductance of fast INa (gNa). With gpNa at 0.1% gNa, the AP duration at 90% repolarization (APD90) was initially lengthened to 2.6-fold that in control. Under regular stimulation at 1 Hz it shortened progressively to 1.37-fold control APD90, and intracellular [Na+]i increased by 6% with a time constant of 106 s. Further increasing gpNa to 0.2% gNa caused an immediate increase in APD90 to 5.7-fold that in control, which decreased to 2.2-fold that in control in 30s stimulation at 1 Hz. At this time diastolic [Na+]i and [Ca2+]i were, respectively, 34% and 52% higher than in control and spontaneous erratic SR Ca release occurred. In the presence of IpNa causing 46% lengthening of APD90, the model cell displayed arrhythmogenic behaviour when external [K+] was lowered to 5 mM from an initial value at 5.4 mM. By contrast, when K+ currents IKr and IKs were lowered in the model cell to produce the same lengthening of APD90, no proarrhythmic behaviour was observed, even when external [K+] was lowered to 2.5 mM.
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28
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Höger U, Torkkeli PH, French AS. Ratiometric calcium concentration estimation using LED excitation during mechanotransduction in single sensory neurons. J Neurosci Methods 2007; 164:255-60. [PMID: 17572505 DOI: 10.1016/j.jneumeth.2007.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 05/05/2007] [Accepted: 05/05/2007] [Indexed: 10/23/2022]
Abstract
In a previous study using Oregon Green BAPTA-1 fluorescence we found that intracellular calcium concentration in spider mechanoreceptor neurons rose during mechanical stimulation. We also showed that calcium elevation required the opening of voltage-dependent calcium channels by action potentials, and could not be produced by the receptor potential alone. While evidence for mechanisms of calcium elevation in these neurons was clear, our estimates of actual calcium concentration depended on properties of the fluorescent dye in the neuron cytoplasm that could not be verified. We have now developed a method for ratiometric estimation of calcium concentration in these neurons using Fura Red dye, excitation by two light emitting diodes (LEDs) of different wavelengths, and an avalanche photodiode fluorescence detector. The method is simple and economical to implement, allows concentration changes to be measured in the millisecond time range, and could easily be applied to a wide range of preparations. Resting calcium concentration in these neurons was about 70nM and rose to a maximum of about 400nM at firing rates above 20 action potentials per second.
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Affiliation(s)
- Ulli Höger
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1X5
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29
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Titov VN. [Mediators of the parameter constancy preservation in the local intercellular environmental pools, the differential nephron segmental function, and arterial hypertension]. Klin Lab Diagn 2007:6-18. [PMID: 17915481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
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30
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Pieraut S, Laurent-Matha V, Sar C, Hubert T, Méchaly I, Hilaire C, Mersel M, Delpire E, Valmier J, Scamps F. NKCC1 phosphorylation stimulates neurite growth of injured adult sensory neurons. J Neurosci 2007; 27:6751-9. [PMID: 17581962 PMCID: PMC6672700 DOI: 10.1523/jneurosci.1337-07.2007] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peripheral nerve section promotes regenerative, elongated neuritic growth of adult sensory neurons. Although the role of chloride homeostasis, through the regulation of ionotropic GABA receptors, in the growth status of immature neurons in the CNS begins to emerge, nothing is known of its role in the regenerative growth of injured adult neurons. To analyze the intracellular Cl- variation after a sciatic nerve section in vivo, gramicidin perforated-patch recordings were used to study muscimol-induced currents in mice dorsal root ganglion neurons isolated from control and axotomized neurons. We show that the reversal potential of muscimol-induced current, E(GABA-A), was shifted toward depolarized potentials in axotomized neurons. This was attributable to Cl- influx because removal of extracellular Cl- prevented this shift. Application of bumetanide, an inhibitor of NKCC1 cotransporter and E(GABA-A) recordings in sensory neurons from NKCC1-/- mice, identified NKCC1 as being responsible for the increase in intracellular Cl- in axotomized neurons. In addition, we demonstrate with a phospho-NKCC1 antibody that nerve injury induces an increase in the phosphorylated form of NKCC1 in dorsal root ganglia that could account for intracellular Cl- accumulation. Time-lapse recordings of the neuritic growth of axotomized neurons show a faster growth velocity compared with control. Bumetanide, the intrathecal injection of NKCC1 small interfering RNA, and the use of NKCC1-/- mice demonstrated that NKCC1 is involved in determining the velocity of elongated growth of axotomized neurons. Our results clearly show that NKCC1-induced increase in intracellular chloride concentration is a major event accompanying peripheral nerve regeneration.
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Affiliation(s)
- Simon Pieraut
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | - Valérie Laurent-Matha
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Ilana Méchaly
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
| | | | | | - Eric Delpire
- Vanderbilt University, Nashville, Tennessee 37235
| | - Jean Valmier
- Inserm, Unité 583, F-34000 Montpellier, France
- Université Montpellier II, F-34000 Montpellier, France
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31
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Abstract
The outer hair cell (OHC) in the cochlea is believed to actively enhance the cochlear sensitivity and frequency selectivity. Besides the well-known axial length change of the OHC, the bending mode of the OHC may also contribute to the stereocilium deflection. To investigate the contribution of the OHC bending to the stereocilium deflection, and the active process in the cochlea, we develop a simple kinematic model of the organ of Corti, consisting of the reticular lamina, the stereocilia and tectorial membrane. The electrically evoked axial length change and bending of the OHC are simulated, and their contributions to the stereocilium deflection are obtained. At the apical turn of the cochlea, the bending mode of the OHC results in stereocilium deflection comparable to that due to the axisymmetric length change of the OHC. At the basal turn, the contribution of the bending mode to the stereocilium deflection becomes insignificant compared to that of the axisymmetric mode.
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Affiliation(s)
- Hailong Li
- Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore
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32
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Milano A, De Rosa V, Iaffaioli RV, Caponigro F. Downstream intracellular effectors of epidermal growth factor receptor as targets for anticancer therapy. Expert Opin Ther Targets 2007; 11:771-82. [PMID: 17504015 DOI: 10.1517/14728222.11.6.771] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In recent years, the knowledge about mutations in components of the intracellular signal transduction pathway has greatly improved. Pivotal target molecules, such as Ras, PI3K, mammalian target of rapamycin (mTOR) and PKC, form an important biochemical network, which, when mutated, drives cell growth in an unlimited manner. Cancer cells have been shown to be able to harness different growth factor signalling pathways. Protein kinase inhibitors, targeted to the above pathways, have demonstrated activity against several solid tumours and are generally better tolerated than standard cytotoxic agents. The future challenge will be to find the most clever way to use combinations of these novel compounds.
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Affiliation(s)
- Amalia Milano
- Istituto Nazionale Tumori Fondazione G. Pascale, Via M. Semmola, 80131 Napoli, Italy.
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33
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Abstract
The intracellular molecular mechanism that controls the timing of oligodendrocyte differentiation remains unknown. Temple and Raff (1986) previously showed that an oligodendrocyte precursor cell (OPC) can divide a maximum of approximately eight times before its daughter cells simultaneously cease proliferating and differentiate into oligodendrocytes. They postulated that over time the level of an intracellular molecule might synchronously change in each daughter cell, ultimately reaching a level that prohibited additional proliferation. Here, we report the discovery of such a molecule, the cyclin-dependent kinase inhibitor p57(Kip2) (Cdkn1c). We show in vitro that all daughters of a clone of OPCs express similar levels of p57(Kip2), that p57(Kip2) levels increase over time in proliferating OPCs, and that p57(Kip2) levels regulate how many times an OPC can divide before differentiating. These findings reveal a novel part of the mechanism by which OPCs measure time and are likely to extend to similar timers in many other precursor cell types.
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Affiliation(s)
- Jason C Dugas
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94305-5125, USA.
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Szczesna-Cordary D, Jones M, Moore JR, Watt J, Kerrick WGL, Xu Y, Wang Y, Wagg C, Lopaschuk GD. Myosin regulatory light chain E22K mutation results in decreased cardiac intracellular calcium and force transients. FASEB J 2007; 21:3974-85. [PMID: 17606808 DOI: 10.1096/fj.07-8630com] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The glutamic acid to lysine mutation at the 22nd amino acid residue (E22K) in the human cardiac myosin regulatory light chain (RLC) gene causes familial hypertrophic cardiomyopathy (FHC) with a phenotype of midventricular obstruction and septal hypertrophy. Our recent histopathology results have shown that the hearts of transgenic E22K mice (Tg-E22K) resemble those of human patients, demonstrating enlarged interventricular septa and papillary muscles. In this study, we show no effect of the E22K mutation on the kinetics of mutated myosin in its ATP-powered interaction with fluorescently labeled single actin filaments compared to nontransgenic or transgenic wild-type (Tg-WT) control mice. Likewise, no change in cross-bridge dissociation rates (g(app)) was observed in freshly skinned papillary muscle fibers. In contrast, maximal force and ATPase were decreased approximately 20% in Tg-E22K skinned papillary muscle fibers and intracellular [Ca2+] and force transients were significantly decreased in intact papillary muscle fibers from Tg-E22K compared to Tg-WT mice. Moreover, energy metabolism measured in isolated working Tg-E22K mouse hearts perfused under conditions of physiologically relevant levels of metabolic demand was similar in Tg-E22K and control hearts before and after 20 min of no-flow ischemia. Our results suggest that the pathological response observed in the E22K myocardium might be triggered by mutation induced changes in the properties of the RLC Ca2+-Mg2+ site, the state of the Ca2+/Mg2+ occupancy and consequently the Ca2+ buffering ability of the RLC. By decreasing the affinity of the RLC for Ca2+, the E22K mutation most likely promotes a Mg2+-saturated RLC producing less force and ATPase than the Ca2+-saturated RLC of WT fibers. Decreased Ca2+ binding may also lead to faster Ca2+ dissociation kinetics in Tg-E22K intact fibers resulting in decreased duration and amplitude of [Ca2+] and force transients. These changes when placed in vivo would result in higher workloads and consequently cardiac hypertrophy.
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Affiliation(s)
- Danuta Szczesna-Cordary
- University of Miami School of Medicine, Department of Molecular & Cellular Pharmacology (R-189), P.O. Box 016189, 1600 NW 10 Ave, Rm. 6113, Miami, FL 33101, USA.
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35
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Bouzigues C, Morel M, Triller A, Dahan M. Asymmetric redistribution of GABA receptors during GABA gradient sensing by nerve growth cones analyzed by single quantum dot imaging. Proc Natl Acad Sci U S A 2007; 104:11251-6. [PMID: 17592112 PMCID: PMC2040885 DOI: 10.1073/pnas.0702536104] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During development of the nervous system, the tip of a growing axon, the growth cone (GC), must respond accurately to stimuli that direct its growth. This axonal navigation depends on extracellular concentration gradients of numerous guidance cues, including GABA. GCs can detect even weak directional signals, yet the mechanisms underlying this sensitivity remain unclear. Past studies in other eukaryotic chemotactic systems have pointed to the role of the spatial reorganization of the transduction pathway in their sensitive response. Here we have developed a single-molecule assay to observe individual GABA(A) receptors (GABA(A)Rs) in the plasma membrane of nerve GCs subjected to directional stimuli. We report that in the presence of an external GABA gradient GABA(A)Rs redistribute asymmetrically across the GC toward the gradient source. Single-particle tracking of GABA(A)Rs shows that the redistribution results from transient interactions between the receptors and the microtubules. Moreover, the relocalization is accompanied by an enhancement in the asymmetry of intracellular calcium concentration. Altogether, our results reveal a microtubule-dependent polarized reorganization of chemoreceptors at the cell surface and suggest that this polarization serves as an amplification step in GABA gradient sensing by nerve GCs.
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Affiliation(s)
- Cédric Bouzigues
- *Laboratoire Kastler Brossel, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8552, Physics Department, Ecole Normale Supérieure, and Université Pierre et Marie Curie-Paris 6, 24, Rue Lhomond, 75005 Paris, France; and
| | - Mathieu Morel
- *Laboratoire Kastler Brossel, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8552, Physics Department, Ecole Normale Supérieure, and Université Pierre et Marie Curie-Paris 6, 24, Rue Lhomond, 75005 Paris, France; and
| | - Antoine Triller
- Institut National de la Santé et de la Recherche Médicale, Unité 789, Biologie Cellulaire de la Synapse Normale et Pathologique, and
- Biology Department, Ecole Normale Supérieure, 46, Rue d'Ulm, 75005 Paris, France
| | - Maxime Dahan
- *Laboratoire Kastler Brossel, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8552, Physics Department, Ecole Normale Supérieure, and Université Pierre et Marie Curie-Paris 6, 24, Rue Lhomond, 75005 Paris, France; and
- Biology Department, Ecole Normale Supérieure, 46, Rue d'Ulm, 75005 Paris, France
- To whom correspondence should be addressed. E-mail:
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Dunoyer P, Himber C, Ruiz-Ferrer V, Alioua A, Voinnet O. Intra- and intercellular RNA interference in Arabidopsis thaliana requires components of the microRNA and heterochromatic silencing pathways. Nat Genet 2007; 39:848-56. [PMID: 17558406 DOI: 10.1038/ng2081] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Accepted: 05/18/2007] [Indexed: 12/12/2022]
Abstract
In RNA interference (RNAi), double-stranded RNA (dsRNA) is processed into short interfering RNA (siRNA) to mediate sequence-specific gene knockdown. The genetics of plant RNAi is not understood, nor are the bases for its spreading between cells. Here, we unravel the requirements for biogenesis and action of siRNAs directing RNAi in Arabidopsis thaliana and show how alternative routes redundantly mediate this process under extreme dsRNA dosages. We found that SMD1 and SMD2, required for intercellular but not intracellular RNAi, are allelic to RDR2 and NRPD1a, respectively, previously implicated in siRNA-directed heterochromatin formation through the action of DCL3 and AGO4. However, neither DCL3 nor AGO4 is required for non-cell autonomous RNAi, uncovering a new pathway for RNAi spreading or detection in recipient cells. Finally, we show that the genetics of RNAi is distinct from that of antiviral silencing and propose that this experimental silencing pathway has a direct endogenous plant counterpart.
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Affiliation(s)
- Patrice Dunoyer
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS) UPR2357, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
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Yamasaki S, Sakata-Sogawa K, Hasegawa A, Suzuki T, Kabu K, Sato E, Kurosaki T, Yamashita S, Tokunaga M, Nishida K, Hirano T. Zinc is a novel intracellular second messenger. ACTA ACUST UNITED AC 2007; 177:637-45. [PMID: 17502426 PMCID: PMC2064209 DOI: 10.1083/jcb.200702081] [Citation(s) in RCA: 410] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Zinc is an essential trace element required for enzymatic activity and for maintaining the conformation of many transcription factors; thus, zinc homeostasis is tightly regulated. Although zinc affects several signaling molecules and may act as a neurotransmitter, it remains unknown whether zinc acts as an intracellular second messenger capable of transducing extracellular stimuli into intracellular signaling events. In this study, we report that the cross-linking of the high affinity immunoglobin E receptor (Fcɛ receptor I [FcɛRI]) induced a release of free zinc from the perinuclear area, including the endoplasmic reticulum in mast cells, a phenomenon we call the zinc wave. The zinc wave was dependent on calcium influx and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase activation. The results suggest that the zinc wave is involved in intracellular signaling events, at least in part by modulating the duration and strength of FcɛRI-mediated signaling. Collectively, our findings indicate that zinc is a novel intracellular second messenger.
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Affiliation(s)
- Satoru Yamasaki
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa, Japan
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Garattini E, Gianni M, Terao M. Retinoids as Differentiating Agents in Oncology: A Network of Interactions with Intracellular Pathways as the Basis for Rational Therapeutic Combinations. Curr Pharm Des 2007; 13:1375-400. [PMID: 17506722 DOI: 10.2174/138161207780618786] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retinoic acid and natural as well as synthetic derivatives (retinoids) are promising anti-neoplastic agents endowed with both therapeutic and chemopreventive potential. Although the treatment of acute promyelocic leukemia with all-trans retinoic acid is an outstanding example, the full potential of retinoids in oncology has not yet been exploited and a more generalized use of these compounds is not yet a reality. This may be the result of issues such as natural and induced resistance as well as local and systemic toxicity. One way to enhance the therapeutic and chemopreventive activity of retinoic acid and derivatives is to identify rational combinations between these compounds and other pharmacological agents. This is now possible given the wealth of information available on the biochemical and molecular mechanisms underlying the biological activity of retinoids. At the cellular level, the anti-leukemia and anti-cancer activity of retinoids is the result of three main actions, cell-differentiation, growth inhibition and apoptosis. At the molecular level, retinoids act through the activation of nuclear-retinoic-acid-receptor-dependent and-independent pathways. The cellular pathways and molecular networks relevant for retinoid activity are modulated by a panoply of other intra-cellular and extra-cellular pathways that may be targeted by known drugs and other experimental therapeutics. The review article aims to summarize and critically discuss the available knowledge in the field and provide a rational framework that may be useful for the design of effective drug combinations with the potential to enhance the therapeutic index of retinoids.
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Affiliation(s)
- Enrico Garattini
- Laboratory of Molecular Biology, Centro Catullo e Daniela Borgomainerio, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
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Vitko I, Bidaud I, Arias JM, Mezghrani A, Lory P, Perez-Reyes E. The I-II loop controls plasma membrane expression and gating of Ca(v)3.2 T-type Ca2+ channels: a paradigm for childhood absence epilepsy mutations. J Neurosci 2007; 27:322-30. [PMID: 17215393 PMCID: PMC6672065 DOI: 10.1523/jneurosci.1817-06.2007] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Calcium currents via low-voltage-activated T-type channels mediate burst firing, particularly in thalamic neurons. Considerable evidence supports the hypothesis that overactive T-channels may contribute to thalamocortical dysrhythmia, including absence epilepsy. Single nucleotide polymorphisms in one of the T-channel genes (CACNA1H, which encodes Ca(v)3.2) are associated with childhood absence epilepsy in a Chinese population. Because only a fraction of these polymorphisms are predicted to increase channel activity and neuronal firing, we hypothesized that other channel properties may be affected. Here we describe that all the polymorphisms clustered in the intracellular loop connecting repeats I and II (I-II loop) increase the surface expression of extracellularly tagged Ca(v)3.2 channels. The functional domains within the I-II loop were then mapped by deletion analysis. The first 62 amino acids of the loop (post IS6) are involved in regulating the voltage dependence of channel gating and inactivation. Similarly, the last 15 amino acids of the loop (pre IIS1) are involved in channel inactivation. In contrast, the central region of I-II loop regulates surface expression, with no significant effect on channel biophysics. Electrophysiology, luminometry, fluorescence-activated cell sorting measurements, and confocal microscopy studies demonstrate that deletion of this central region leads to enhanced surface expression of channels from intracellular compartments to the plasma membrane. These results provide novel insights into how CACNA1H polymorphisms may contribute to Ca(v)3.2 channel overactivity and consequently to absence epilepsy and establish the I-II loop as an important regulator of Ca(v)3.2 channel function and expression.
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Affiliation(s)
- Iuliia Vitko
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22904, and
| | - Isabelle Bidaud
- Departement de Physiologie, Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Santé et de la Recherche Médicale, Unité 661, Université Montpellier I et II, 34090 Montpellier, France
| | - Juan Manuel Arias
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22904, and
| | - Alexandre Mezghrani
- Departement de Physiologie, Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Santé et de la Recherche Médicale, Unité 661, Université Montpellier I et II, 34090 Montpellier, France
| | - Philippe Lory
- Departement de Physiologie, Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5203, Institut National de la Santé et de la Recherche Médicale, Unité 661, Université Montpellier I et II, 34090 Montpellier, France
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22904, and
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Kuniyeda K, Okuno T, Terawaki K, Miyano M, Yokomizo T, Shimizu T. Identification of the Intracellular Region of the Leukotriene B4 Receptor Type 1 That Is Specifically Involved in Gi Activation. J Biol Chem 2007; 282:3998-4006. [PMID: 17158791 DOI: 10.1074/jbc.m610540200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many G-protein-coupled receptors can activate more than one G-protein subfamily member. Leukotriene B4 receptor type 1 (BLT1) is a high affinity G-protein-coupled receptors for leukotriene B4 functioning in host defense, inflammation, and immunity. Previous studies have shown that BLT1 utilizes different G-proteins (the Gi family and G16 G-proteins) in mediating diverse cellular events and that truncation of the cytoplasmic tail of BLT1 does not impair activation of Gi and G16 proteins. To determine responsive regions of BLT1 for G-protein coupling, we performed an extensive mutagenesis study of its intracellular loops. Three intracellular loops (i1, i2, and i3) of BLT1 were found to be important for both Gi and G16 coupling, as judged by Gi-dependent guanosine 5'-(gamma-thio) triphosphate (GTPgammaS) binding and G16-dependent inositol phosphate accumulation assays. The i3-1 mutant, with a mutation at the i3 amino terminus, exhibited greatly reduced GTPgammaS binding but intact inositol phosphate accumulation triggered by leukotriene B4 stimulation. These results suggest that the i3-1 region is required only for Gi activation. Moreover, in the i3-1 mutant, the deficiency in Gi activation was accompanied by a loss of the high affinity leukotriene B4 binding state seen with the wild type receptor. A three-dimensional model of BLT1 constructed based on the structure of bovine rhodopsin suggests that the i3-1 region may consist of the cytoplasmic end of the transmembrane helix V, which protrudes the helix into the cytoplasm. From mutational studies and three-dimensional modeling, we propose that the extended cytoplasmic helix connected to the transmembrane helix V of BLT1 might be a key region for selective activation of Gi proteins.
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Affiliation(s)
- Kanako Kuniyeda
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Abstract
In nearly every vertebrate species, elevated intracellular cAMP maintains oocytes in prophase I of meiosis. Prior to ovulation, gonadotropins trigger various intra-ovarian processes, including the breakdown of gap junctions, the activation of EGF receptors, and the secretion of steroids. These events in turn decrease intracellular cAMP levels in select oocytes to allow meiotic progression, or maturation, to resume. Studies suggest that cAMP levels are kept elevated in resting oocytes by constitutive G protein signaling, and that the drop in intracellular cAMP that accompanies maturation may be due in part to attenuation of this inhibitory G protein-mediated signaling. Interestingly, one of these G protein regulators of meiotic arrest is the Galpha(s) protein, which stimulates adenylyl cyclase to raise intracellular cAMP in two important animal models of oocyte development: Xenopus leavis frogs and mice. In addition to G(alpha)(s), constitutive Gbetagamma activity similarly stimulates adenylyl cyclase to raise cAMP and prevent maturation in Xenopus oocytes; however, the role of Gbetagamma in regulating meiosis in mouse oocytes has not been examined. Here we show that Gbetagamma does not contribute to the maintenance of murine oocyte meiotic arrest. In fact, contrary to observations in frog oocytes, Gbetagamma signaling in mouse oocytes reduces cAMP and promotes oocyte maturation, suggesting that Gbetagamma might in fact play a positive role in promoting oocyte maturation. These observations emphasize that, while many general concepts and components of meiotic regulation are conserved from frogs to mice, specific differences exist that may lead to important insights regarding ovarian development in vertebrates.
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Affiliation(s)
- Arvind Gill
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, Texas 75390-8857, USA
| | - Stephen R Hammes
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, Texas 75390-8857, USA
- Corresponding author: Phone: 214-648-3749, FAX: 214-648-7934,
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Abstract
The cardiac sarcolemmal Na+-Ca2+ exchanger (NCX1) influences cardiac contractility by extruding Ca2+ from myocytes. As a Ca2+ efflux mechanism, the exchanger plays a prominent role in Ca2+ homeostasis. To track NCX1 and study changes in conformation, NCX1 was tagged with derivatives of green fluorescent protein. Cyan (CFP) and yellow (YFP) fluorescent proteins were used for both visualization of the protein in HEK cells and fluorescent resonance energy transfer (FRET). CFP or YFP was inserted at position 266, 371, 467, or 548 of the large intracellular loop of NCX1 located between transmembrane segments 5 and 6. These constructs were tested for functional activity and visualized for cell surface expression. All constructs were targeted to the plasma membrane. Transport properties were assessed by both 45Ca2+ uptake and electrophysiological measurements. The fluorescent-tagged exchangers had similar biophysical properties to the wild type NCX1. Unexpectedly, all constructs retain their sensitivity to regulation by cytoplasmic Na+ and Ca2+ ions. FRET analysis indicates the proximity of NCX1 to plasma membrane phosphatidylinositol 4,5-bisphosphate. These results indicate that insertion of CFP or YFP into the large intracellular loop of NCX1 protein does not impair exchanger properties. These constructs will be useful to further characterize the biological properties of the exchanger in intact cells.
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Affiliation(s)
- Michela Ottolia
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1760, USA
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Abstract
BACKGROUND Vasopressin is essential for cardiovascular homeostasis, acting via the kidney to regulate water resorption, on the vasculature to regulate smooth muscle tone, and as a central neurotransmitter, modulating brainstem autonomic function. Although it is released in response to stress or shock states, a relative deficiency of vasopressin has been found in prolonged vasodilatory shock, such as is seen in severe sepsis. In this circumstance, exogenous vasopressin has marked vasopressor effects, even at doses that would not affect blood pressure in healthy individuals. These two findings provide the rationale for the use of vasopressin in the treatment of septic shock. However, despite considerable research attention, the mechanisms for vasopressin deficiency and hypersensitivity in vasodilatory shock remain unclear. OBJECTIVE To summarize vasopressin's synthesis, physiologic roles, and regulation and then review the literature describing its vascular receptors and downstream signaling pathways. A discussion of potential mechanisms underlying vasopressin hypersensitivity in septic shock follows, with reference to relevant clinical, in vivo, and in vitro experimental evidence. DATA SOURCE Search of the PubMed database (keywords: vasopressin and receptors and/or sepsis or septic shock) for articles published in English before May 2006 and manual review of article bibliographies. DATA SYNTHESIS AND CONCLUSIONS The pathophysiologic mechanism underlying vasopressin hypersensitivity in septic shock is probably multifactorial. It is doubtful that this phenomenon is merely the consequence of replacing a deficiency. Changes in vascular receptors or their signaling and/or interactions between vasopressin, nitric oxide, and adenosine triphosphate-dependent potassium channels are likely to be relevant. Further translational research is required to improve our understanding and direct appropriate educated clinical use of vasopressin.
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MESH Headings
- Antidiuretic Agents/pharmacology
- Antidiuretic Agents/therapeutic use
- Autonomic Nervous System Diseases/etiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Catecholamines/physiology
- Homeostasis/drug effects
- Homeostasis/physiology
- Humans
- Hypothalamo-Hypophyseal System/drug effects
- Hypothalamo-Hypophyseal System/physiology
- Intracellular Fluid/drug effects
- Intracellular Fluid/physiology
- Kidney/drug effects
- Kidney/physiopathology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Nitric Oxide/physiology
- Pituitary-Adrenal System/drug effects
- Pituitary-Adrenal System/physiology
- Receptors, Oxytocin/drug effects
- Receptors, Oxytocin/physiology
- Receptors, Vasopressin/drug effects
- Receptors, Vasopressin/physiology
- Shock, Septic/drug therapy
- Shock, Septic/etiology
- Shock, Septic/physiopathology
- Sodium-Potassium-Exchanging ATPase/drug effects
- Sodium-Potassium-Exchanging ATPase/physiology
- Vasoconstrictor Agents/pharmacology
- Vasoconstrictor Agents/therapeutic use
- Vasopressins/pharmacology
- Vasopressins/physiology
- Vasopressins/therapeutic use
- Water-Electrolyte Balance/drug effects
- Water-Electrolyte Balance/physiology
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Affiliation(s)
- Lucinda K Barrett
- Department of Medicine and Wolfson Institute for Biomedical Research, University College London, London, UK
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Aslanova UF, Morimoto T, Farajov EI, Kumagai N, Nishino M, Sugawara N, Ohsaga A, Maruyama Y, Tsuchiya S, Takahashi S, Kondo Y. Chloride-dependent intracellular pH regulation via extracellular calcium-sensing receptor in the medullary thick ascending limb of the mouse kidney. TOHOKU J EXP MED 2007; 210:291-300. [PMID: 17146194 DOI: 10.1620/tjem.210.291] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The extracellular calcium-sensing receptor (CaSR) located in either luminal or basolateral cell membranes of various types of renal tubules including proximal tubules, Henle's loop and collecting ducts has been thought to play a fundamental role in electrolyte metabolism. To further identify the physiological roles of the CaSR, we examined the effects of Ca(2+) and calcimimetics neomycin (Neo), gentamicin and gadolinium chloride (Gd(3+)) on the intracellular pH (pHi) of in vitro microperfused mouse medullary thick ascending limb (mTAL) cells of Henle's loop, by loading the cells with fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein and measuring the ratio of fluorescence emission at 530 nm after exciting the dye at 490 and 440 nm. In a steady-state condition in Hepes-buffered solution, the pHi in the mTALs was 7.29 +/- 0.04 (n = 9). A concentration of 200 micromol/l Neo in the basolateral side decreased the pHi after 1 min by -0.13 +/- 0.02 (n = 34, p < 0.0001). The other calcimimetics showed similar effects on pHi, whereas none of these calcimimetics in the lumen affected pHi. Na(+) removal or the inhibition of Na(+) and proton transport with amiloride, bumetanide, or bafilomycin did not eliminate the effect of Neo on pHi. On the other hand, Cl(-) removal clearly eliminated the Neo-induced pHi decrease (-0.06 +/- 0.01 vs -0.00 +/- 0.05 in Cl(-) removal, n = 4, p < 0.003). Thus, we have demonstrated for the first time that the CaSR is involved in the regulation of the pHi in the mTAL and requires Cl(-) to exert its effect.
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Jury EC, Isenberg DA, Mauri C, Ehrenstein MR. Atorvastatin restores Lck expression and lipid raft-associated signaling in T cells from patients with systemic lupus erythematosus. J Immunol 2007; 177:7416-22. [PMID: 17082661 DOI: 10.4049/jimmunol.177.10.7416] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Loss of tolerance to self-Ags in patients with systemic lupus erythematosus (SLE), a prototypic autoimmune disease, is associated with dysregulation of T cell signaling, including the depletion of total levels of lymphocyte-specific protein kinase (Lck) from sphingolipid-cholesterol-enriched membrane microdomains (lipid rafts). Inhibitors of 3-hyroxy-3-methylgluteryl CoA reductase (statins) can modify the composition of lipid rafts, resulting in alteration of T cell signaling. In this study, we show that atorvastatin targets the distribution of signaling molecules in T cells from SLE patients, by disrupting the colocalization of total Lck and CD45 within lipid rafts, leading to a reduction in the active form of Lck. Upon T cell activation using anti-CD3/anti-CD28 in vitro, the rapid recruitment of total Lck to the immunological synapse was inhibited by atorvastatin, whereas ERK phosphorylation, which is decreased in SLE T cells, was reconstituted. Furthermore, atorvastatin reduced the production of IL-10 and IL-6 by T cells, implicated in the pathogenesis of SLE. Thus, atorvastatin reversed many of the signaling defects characteristic of SLE T cells. These findings demonstrate the potential for atorvastatin to target lipid raft-associated signaling abnormalities in autoreactive T cells and provide a rationale for its use in therapy of autoimmune disease.
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Affiliation(s)
- Elizabeth C Jury
- Department of Medicine, Centre for Rheumatology, University College London, United Kingdom.
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Affiliation(s)
- Laurent Jaeken
- Karel de Grote-Hogeschool University College, Department of Industrial Sciences and Technology, Laboratory of Biochemistry, Hoboken, Antwerp, Belgium.
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47
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Abstract
Dynamic modeling and simulation of signal transduction pathways is an important topic in systems biology and is obtaining growing attention from researchers with experimental or theoretical background. Here we review attempts to analyze and model specific signaling systems. We review the structure of recurrent building blocks of signaling pathways and their integration into more comprehensive models, which enables the understanding of complex cellular processes. The variety of mechanisms found and modeling techniques used are illustrated with models of different signaling pathways. Focusing on the close interplay between experimental investigation of pathways and the mathematical representations of cellular dynamics, we discuss challenges and perspectives that emerge in studies of signaling systems.
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Affiliation(s)
- Edda Klipp
- Max Planck Institute for Molecular Genetics, Ihnestr. 73, 14195 Berlin, Germany
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Simon V, Guidry J, Gettys TW, Tobin AB, Lanier SM. The proto-oncogene SET interacts with muscarinic receptors and attenuates receptor signaling. J Biol Chem 2006; 281:40310-20. [PMID: 17065150 PMCID: PMC2596874 DOI: 10.1074/jbc.m603858200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors mediate cell responses to extracellular stimuli and likely function in the context of a larger signal transduction complex. Utilizing the third intracellular loop of a G protein-coupled receptor in glutathione S-transferase pulldown assays from rat brain lysates coupled with high sensitivity detection methods and subsequent functional studies, we report the identification of SET as a regulator of muscarinic receptor signaling. SET is a putative oncogene reported to inhibit protein phosphatase 2A and regulate gene transcription. SET binds the carboxyl region of the M3-muscarinic receptor i3 loop, and endogenous SET co-immunoprecipitates with intact M3 muscarinic receptor expressed in cells. Small interfering RNA knockdown of endogenous SET in Chinese hamster ovary cells stably expressing the M3 muscarinic receptor augmented receptor-mediated mobilization of intracellular calcium by approximately 35% with no change in agonist EC(50), indicating that interaction of SET with the M3 muscarinic receptor reduces its signaling capacity. SET knockdown had no effect on the mobilization of intracellular calcium by the P2-purinergic receptor, ionomycin, or a direct activator of phospholipase C, indicating a specific regulation of M3 muscarinic receptor signaling. These data provide expanded functionality for SET and a previously unrecognized mechanism for regulation of GPCR signaling capacity.
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MESH Headings
- Amino Acid Sequence
- Animals
- CHO Cells
- Chromosomal Proteins, Non-Histone/deficiency
- Chromosomal Proteins, Non-Histone/genetics
- Chromosomal Proteins, Non-Histone/metabolism
- Chromosomal Proteins, Non-Histone/physiology
- Cricetinae
- DNA-Binding Proteins
- Histone Chaperones
- Humans
- Intracellular Fluid/metabolism
- Intracellular Fluid/physiology
- Mice
- Molecular Sequence Data
- Protein Binding/genetics
- Protein Binding/physiology
- Protein Structure, Tertiary/genetics
- Proto-Oncogene Mas
- Proto-Oncogene Proteins/deficiency
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins/physiology
- RNA, Small Interfering/genetics
- Rats
- Receptor, Muscarinic M2/biosynthesis
- Receptor, Muscarinic M2/genetics
- Receptor, Muscarinic M2/metabolism
- Receptor, Muscarinic M2/physiology
- Receptor, Muscarinic M3/antagonists & inhibitors
- Receptor, Muscarinic M3/genetics
- Receptor, Muscarinic M3/metabolism
- Receptor, Muscarinic M3/physiology
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Signal Transduction/genetics
- Signal Transduction/physiology
- Transcription Factors/deficiency
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription Factors/physiology
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Affiliation(s)
- Violaine Simon
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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Brixius K, Frank KF, Bölck B, Hoyer F, Schwinger RHG. [Reverse remodeling of the intracellular Ca(2+)-homeostasis: new concepts of pathophysiology and therapy of heart failure]. Wien Med Wochenschr 2006; 156:209-15. [PMID: 16823538 DOI: 10.1007/s10354-005-0239-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Accepted: 10/21/2005] [Indexed: 01/08/2023]
Abstract
Cardiac contraction is dependent on a rapid alteration of the intracellular Ca(2+) concentration, especially the Ca(2+) released during systole. In end-stage heart failure, cardiac contractility is depressed due to alterations in the structure and function of proteins or protein complexes. Over recent years, new insights have been obtained regarding the regulation of the intracellular Ca(2+) homeostasis and its pathophysiological alteration in end-stage heart failure. This review focuses on the mechanisms involved in the release of Ca(2+) from the sarcoplasmic reticulum (SR) during systole via the ryanodine receptors and the Ca(2+)-uptake into the SR by the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA 2a). In addition, new therapeutic options will be introduced which may be of importance for the treatment of heart failure patients.
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Affiliation(s)
- Klara Brixius
- Labor für Herzmuskelphysiologie und Molekulare Kardiologie, Klinik III für Innere Medizin, Köln
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Fujita T, Ogino M, Daigo F, Yamaguchi T, Majima M. Intracellular Ca2+ contributes to K+-induced increase in renal kallikrein secretion. Int Immunopharmacol 2006; 6:1487-95. [PMID: 16846843 DOI: 10.1016/j.intimp.2006.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Revised: 01/26/2006] [Accepted: 05/24/2006] [Indexed: 11/23/2022]
Abstract
We have reported that natriuretic effects of K(+) are involved in enhancement of renal kallikrein-kinin system. The study was aimed to examine 1) comparison of augmentative effects of K(+) on urinary KK excretion with non-specific washout effects by trichlormethiazide (thiazide), polyethyleneglycol 200 (PEG) and rapid physiological saline infusion, 2) contribution of Ca(2+) on the K(+)-induced increase in renal kallikrein secretion. Renal kallikrein activities were measured as fluorescence activities of methylcoumarinylamide-labeled synthetic substrate of tissue kallikrein (TK). Increases in urinary TK excretion were simultaneously observed with diuresis caused by thiazide, PEG, and rapid saline infusion. K(+) infusion increased urinary TK excretion with a diuretic response same as the control. K(+), but not thiazide, showed an early increase in renal TK secretion dose dependently in the kidney slices. Increases in renal TK secretion persisted during treatment with K(+). Neither voltage-dependent Ca(2+)-channel blockers such as verapamil and nifedipine nor simultaneous treatment of EDTA affected on the K(+)-induced increase in renal TK secretion. While, EDTA decreased the K(+)-induced increases in renal TK secretion with time. Caffeine also had an early effect on the increase in renal TK secretion. K(+)-induced increases in renal TK secretion was demonstrated even after treatment with ryanodine or depletion of caffeine-sensitive intracellular Ca(2+) by thapsigargin. It was indicated that the increase in renal TK secretion by K(+) depends on the intracellular Ca(2+) and the caffeine-sensitive release of intracellular Ca(2+) may not be involved in this response. Mechanisms for the K(+)-induced increase in renal TK secretion needs to be further elucidated.
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Affiliation(s)
- Tomoe Fujita
- Department of Pharmacology, Kitasato University, School of Medicine, Kitasato 1-15-1, Sagamihara, Kanagawa 228-8555, Japan.
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