scholarly journals Enhanced phosphorylation of Na+–Cl− co-transporter in experimental metabolic syndrome: role of insulin

2012 ◽  
Vol 123 (11) ◽  
pp. 635-647 ◽  
Author(s):  
Radko Komers ◽  
Shaunessy Rogers ◽  
Terry T. Oyama ◽  
Bei Xu ◽  
Chao-Ling Yang ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Time Course ◽  
Kinase Inhibitor ◽  
Endogenous Expression ◽  
The Metabolic Syndrome ◽  
Mammalian Cell Lines ◽  
Phosphoinositide 3 Kinase

In the present study, we investigated the activity of the thiazide-sensitive NCC (Na+–Cl− co-transporter) in experimental metabolic syndrome and the role of insulin in NCC activation. Renal responses to the NCC inhibitor HCTZ (hydrochlorothiazide), as a measure of NCC activity in vivo, were studied in 12-week-old ZO (Zucker obese) rats, a model of the metabolic syndrome, and in ZL (Zucker lean) control animals, together with renal NCC expression and molecular markers of NCC activity, such as localization and phosphorylation. Effects of insulin were studied further in mammalian cell lines with inducible and endogenous expression of this molecule. ZO rats displayed marked hyperinsulinaemia, but no differences in plasma aldosterone, compared with ZL rats. In ZO rats, natriuretic and diuretic responses to NCC inhibition with HCTZ were enhanced compared with ZL rats, and were associated with a decrease in BP (blood pressure). ZO rats displayed enhanced Thr53 NCC phosphorylation and predominant membrane localization of both total and phosphorylated NCC, together with a different profile in expression of SPAK (Ste20-related proline/alanine-rich kinase) isoforms, and lower expression of WNK4. In vitro, insulin induced NCC phosphorylation, which was blocked by a PI3K (phosphoinositide 3-kinase) inhibitor. Insulin-induced reduction in WNK4 expression was also observed, but delayed compared with the time course of NCC phosphorylation. In summary, we report increased NCC activity in hyperinsulinaemic rodents in conjunction with the SPAK expression profile consistent with NCC activation and reduced WNK4, as well as an ability of insulin to induce NCC stimulatory phosphorylation in vitro. Together, these findings indicate that hyperinsulinaemia is an important driving force of NCC activity in the metabolic syndrome with possible consequences for BP regulation.

scholarly journals Two Quenchers Formed During Photodamage of Phostosystem II and The Role of One Quencher in Preemptive Photoprotection

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alonso Zavafer ◽  
Ievgeniia Iermak ◽  
Mun Hon Cheah ◽  
Wah Soon Chow
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Time Course ◽  
Physiological Role ◽  
Reaction Centre ◽  
Time Resolved ◽  
Fluorescence Quencher

AbstractThe quenching of chlorophyll fluorescence caused by photodamage of Photosystem II (qI) is a well recognized phenomenon, where the nature and physiological role of which are still debatable. Paradoxically, photodamage to the reaction centre of Photosystem II is supposed to be alleviated by excitation quenching mechanisms which manifest as fluorescence quenchers. Here we investigated the time course of PSII photodamage in vivo and in vitro and that of picosecond time-resolved chlorophyll fluorescence (quencher formation). Two long-lived fluorescence quenching processes during photodamage were observed and were formed at different speeds. The slow-developing quenching process exhibited a time course similar to that of the accumulation of photodamaged PSII, while the fast-developing process took place faster than the light-induced PSII damage. We attribute the slow process to the accumulation of photodamaged PSII and the fast process to an independent quenching mechanism that precedes PSII photodamage and that alleviates the inactivation of the PSII reaction centre.

Modulation of granulocyte apoptosis can influence the resolution of inflammation

2007 ◽  
Vol 35 (2) ◽  
pp. 288-291 ◽  
Author(s):  
A.G. Rossi ◽  
J.M. Hallett ◽  
D.A. Sawatzky ◽  
M.M. Teixeira ◽  
C. Haslett
Keyword(s):  
Kinase Inhibitor ◽  
Nuclear Factor Κb ◽  
Mitogen Activated Protein Kinase ◽  
Apoptotic Cells ◽  
Resolution Of Inflammation ◽  
Mitogen Activated Protein ◽  
Apoptotic Pathways ◽  
Phosphoinositide 3 Kinase

Apoptosis of granulocytes and the subsequent clearance of apoptotic cells are important processes for the successful resolution of inflammation. Signalling pathways, including those involving NF-κB (nuclear factor κB), MAPK (mitogen-activated protein kinase) and PI3K (phosphoinositide 3-kinase) have been shown to be key regulators of inflammatory cell survival and apoptosis in vitro. In addition, manipulation of such pathways in vivo has indicated that they also play a role in the resolution of inflammation. Furthermore, manipulation of proteins directly involved in the control of apoptosis, such as Bcl-2 family members and caspases, can be targeted in vivo to influence inflammatory resolution. Recently, it has been shown that CDK (cyclin-dependent kinase) inhibitor drugs induce caspase-dependent human neutrophil apoptosis possibly by altering levels of the anti-apoptotic Bcl-2 family member, Mcl-1. Importantly, CDK inhibitor drugs augment the resolution of established ‘neutrophil-dominant’ inflammation by promoting apoptosis of neutrophils. Thus manipulation of apoptotic pathways, together with ensuring macrophage clearance of apoptotic cells, appears to be a viable pharmacological target for reducing established inflammation.

In vivo expression patterns of MyoD, p21, and Rb proteins in myonuclei and satellite cells of denervated rat skeletal muscle

2004 ◽  
Vol 287 (2) ◽  
pp. C484-C493 ◽  
Author(s):  
Minenori Ishido ◽  
Katsuya Kami ◽  
Mitsuhiko Masuhara
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Time Course ◽  
Kinase Inhibitor ◽  
Expression Patterns ◽  
Cell Types ◽  
Cell Nuclei ◽  
Myogenic Regulatory Factor

MyoD, a myogenic regulatory factor, is rapidly expressed in adult skeletal muscles in response to denervation. However, the function(s) of MyoD expressed in denervated muscle has not been adequately elucidated. In vitro, it directly transactivates cyclin-dependent kinase inhibitor p21 (p21) and retinoblastoma protein (Rb), a downstream target of p21. These factors then act to regulate cell cycle withdrawal and antiapoptotic cell death. Using immunohistochemical approaches, we characterized cell types expressing MyoD, p21, and Rb and the relationship among these factors in the myonucleus of denervated muscles. In addition, we quantitatively examined the time course changes and expression patterns among distinct myofiber types of MyoD, p21, and Rb during denervation. Denervation induced MyoD expression in myonuclei and satellite cell nuclei, whereas p21 and Rb were found only in myonuclei. Furthermore, coexpression of MyoD, p21, and Rb was induced in the myonucleus, and quantitative analysis of these factors determined that there was no difference among the three myofiber types. These observations suggest that MyoD may function in myonuclei in response to denervation to protect against denervation-induced apoptosis via perhaps the activation of p21 and Rb, and function of MyoD expressed in satellite cell nuclei may be negatively regulated. The present study provides a molecular basis to further understand the function of MyoD expressed in the myonuclei and satellite cell nuclei of denervated skeletal muscle.

Effectiveness of combined treatment using X-rays and a phosphoinositide 3-kinase inhibitor, ZSTK474, on proliferation of HeLa cells in vitro and in vivo

2011 ◽  
Vol 102 (6) ◽  
pp. 1176-1180 ◽  
Author(s):  
Kazunori Anzai ◽  
Emiko Sekine-Suzuki ◽  
Megumi Ueno ◽  
Mutsumi Okamura ◽  
Hisashi Yoshimi ◽  
...  
Keyword(s):  
Hela Cells ◽  
Kinase Inhibitor ◽  
Combined Treatment ◽  
X Rays ◽  
Phosphoinositide 3 Kinase

scholarly journals Hyaluronic acid-functionalized gelatin hydrogels reveal extracellular matrix signals temper the efficacy of erlotinib against patient-derived glioblastoma specimens

2019 ◽  
Author(s):  
Sara Pedron ◽  
Gabrielle L. Wolter ◽  
Jee-Wei E. Chen ◽  
Sarah E. Laken ◽  
Jann N. Sarkaria ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Tumor Microenvironment ◽  
Kinase Inhibitor ◽  
Egfr Mutations ◽  
Primary Glioblastoma ◽  
Stat3 Phosphorylation

AbstractTherapeutic options to treat primary glioblastoma (GBM) tumors are scarce. GBM tumors with epidermal growth factor receptor (EGFR) mutations, in particular a constitutively active EGFRvIII mutant, have extremely poor clinical outcomes. GBM tumors with concurrent EGFR amplification and active phosphatase and tensin homolog (PTEN) are sensitive to the tyrosine kinase inhibitor erlotinib, but the effect is not durable. A persistent challenge to improved treatment is the poorly understood role of cellular, metabolic, and biophysical signals from the GBM tumor microenvironment on therapeutic efficacy and acquired resistance. The intractable nature of studying GBM cell in vivo motivates tissue engineering approaches to replicate aspects of the complex GBM tumor microenvironment. Here, we profile the effect of erlotinib on two patient-derived GBM specimens: EGFR+ GBM12 and EGFRvIII GBM6. We use a three-dimensional gelatin hydrogel to present brain-mimetic hyaluronic acid (HA) and evaluate the coordinated influence of extracellular matrix signals and EGFR mutation status on GBM cell migration, survival and proliferation, as well as signaling pathway activation in response to cyclic erlotinib exposure. Comparable to results observed in vivo for xenograft tumors, erlotinib exposure is not cytotoxic for GBM6 EGFRvIII specimens. We also identify a role of extracellular HA (via CD44) in altering the effect of erlotinib in GBM EGFR+ cells by modifying STAT3 phosphorylation status. Taken together, we report an in vitro tissue engineered platform to monitor signaling associated with poor response to targeted inhibitors in GBM.

scholarly journals The mechanism of MinD stability modulation by MinE in Min protein dynamics

2021 ◽  
Author(s):  
William C Carlquist ◽  
Eric N Cytrynbaum
Keyword(s):  
Time Course ◽  
Time Lapse ◽  
Membrane Stability ◽  
The Novel ◽  
Dynamic Interactions ◽  
Asymmetric Activation ◽  
Novel Model

The patterns formed both in vivo and in vitro by the Min protein system have attracted much interest because of the complexity of their dynamic interactions given the apparent simplicity of the component parts. Despite both the experimental and theoretical attention paid to this system, the details of the biochemical interactions of MinD and MinE, the proteins responsible for the patterning, are still unclear. For example, no model consistent with the known biochemistry has yet accounted for the observed dual role of MinE in the membrane stability of MinD. Until now, a statistical comparison of models to the time course of Min protein concentrations on the membrane has not been carried out. Such an approach is a powerful way to test existing and novel models that are difficult to test using a purely experimental approach. Here, we extract time series from previously published fluorescence microscopy time lapse images of in vitro experiments and fit two previously described and one novel mathematical model to the data. We find that the novel model, which we call the Asymmetric Activation with Bridged Stability Model, fits the time-course data best. It is also consistent with known biochemistry and explains the dual MinE role via MinE-dependent membrane stability that transitions under the influence of rising MinE to membrane instability with positive feedback. Our results reveal a more complex network of interactions between MinD and MinE underlying Min-system dynamics than previously considered.

scholarly journals Abscisic Acid: A Conserved Hormone in Plants and Humans and a Promising Aid to Combat Prediabetes and the Metabolic Syndrome

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1724
Author(s):  
Mirko Magnone ◽  
Laura Sturla ◽  
Lucrezia Guida ◽  
Sonia Spinelli ◽  
Giulia Begani ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Abscisic Acid ◽  
Glucose Uptake ◽  
Metabolic Response ◽  
The Metabolic Syndrome ◽  
White Adipocytes ◽  
Living Organisms ◽  
Glucose Availability

Abscisic acid (ABA) is a hormone with a very long evolutionary history, dating back to the earliest living organisms, of which modern (ABA-producing) cyanobacteria are likely the descendants, well before separation of the plant and animal kingdoms, with a conserved role as a signal regulating cell responses to environmental challenges. In mammals, nanomolar ABA controls the metabolic response to glucose availability by stimulating glucose uptake in skeletal muscle and adipose tissue with an insulin-independent mechanism and increasing energy expenditure in the brown and white adipose tissues. Activation by ABA of AMP-dependent kinase (AMPK), in contrast to the insulin-induced activation of AMPK-inhibiting Akt, is responsible for stimulation of GLUT4-mediated muscle glucose uptake, and for the browning effect on white adipocytes. Intake of micrograms per Kg body weight of ABA improves glucose tolerance in both normal and in borderline subjects and chronic intake of such a dose of ABA improves blood glucose, lipids and morphometric parameters (waist circumference and body mass index) in borderline subjects for prediabetes and the metabolic syndrome. This review summarizes the most recent results obtained in vivo with microgram amounts of ABA, the role of the receptor LANCL2 in the hormone’s action and the significance of the endowment by mammals of two different hormones controlling the metabolic response to glucose availability. Finally, open issues in need of further investigation and perspectives for the clinical use of nutraceutical ABA are discussed.

scholarly journals The role of phosphoinositide 3-kinase in spreading osteoclasts induced by colony-stimulating factor-1

2001 ◽  
pp. 431-440 ◽  
Author(s):  
S Palacio ◽  
R Felix
Keyword(s):  
Bone Marrow Cells ◽  
Colony Stimulating Factor ◽  
Lipid Kinase ◽  
Growth And Survival ◽  
Phosphoinositide 3 Kinase ◽  
Stimulating Factor ◽  
K Activity

BACKGROUND: Colony-stimulating factor-1 (CSF-1), a growth and survival factor for osteoclasts, stimulates these cells to spread and migrate towards a gradient of CSF-1. This may support the translocation of osteoclasts to new sites on the bone surface to be resorbed. Phosphoinositide 3-kinase (PI 3-K) is a lipid kinase participating in various signal transduction pathways. OBJECTIVE: To investigate the role of PI 3-K in the CSF-1-induced spreading of osteoclasts. METHODS: In isolated rat osteoclasts treated with or without CSF-1, the distribution of PI 3-K and proteins phosphorylated on tyrosine were investigated using immunofluorescence. In murine osteoclast-like cells grown from bone marrow cells co-cultured with osteoblasts, the activation of the PI 3-K by CSF-1 was determined both in vivo and in vitro. In vivo, the enzyme product in the cell was determined after extraction and separation with thin layer chromatography; in vitro, PI 3-K activity was measured in the pellet immunoprecipitated from the cell lysate. RESULTS: Inhibition of PI 3-K blocked the CSF-1-induced spreading of osteoclasts. In spreading osteoclasts, a portion of PI 3-K was translocated to the periphery where proteins phosphorylated on tyrosine appeared simultaneously. In osteoclast-like cells, CSF-1 stimulated PI 3-K activity. This activity could be immunoprecipitated with antibody against phophotyrosine residues. CONCLUSION: PI 3-K participates in the CSF-1-induced spreading of osteoclasts. The activated PI 3-K may induce the reorganization of the cytoskeleton resulting in spreading and migration.

scholarly journals CAPN1 (Calpain1)-Mediated Impairment of Autophagic Flux Contributes to Cerebral Ischemia-Induced Neuronal Damage

Stroke ◽  
2021 ◽  
Author(s):  
Yueyang Liu ◽  
Xiaohang Che ◽  
Haotian Zhang ◽  
Xiaoxiao Fu ◽  
Yang Yao ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Kinase Inhibitor ◽  
Neuronal Damage ◽  
Neuronal Cell ◽  
In Vivo Model ◽  
Autophagic Flux ◽  
Autophagosome Formation

Background and Purpose: CAPN1 (calpain1)—an intracellular Ca 2+ -regulated cysteine protease—can be activated under cerebral ischemia. However, the mechanisms by which CAPN1 activation promotes cerebral ischemic injury are not defined. Methods: In the present study, we used adeno-associated virus-mediated genetic knockdown and pharmacological blockade (MDL-28170) of CAPN1 to investigate the role of CAPN1 in the regulation of the autophagy-lysosomal pathway and neuronal damage in 2 models, rat permanent middle cerebral occlusion in vivo model and oxygen-glucose–deprived primary neuron in vitro model. Results: CAPN1 was activated in the cortex of permanent middle cerebral occlusion–operated rats and oxygen-glucose deprivation–exposed neurons. Genetic and pharmacological inhibition of CAPN1 significantly attenuated ischemia-induced lysosomal membrane permeabilization and subsequent accumulation of autophagic substrates in vivo and in vitro. Moreover, inhibition of CAPN1 increased autophagosome formation by decreasing the cleavage of the autophagy regulators BECN1 (Beclin1) and ATG (autophagy-related gene) 5. Importantly, the neuron-protective effect of MDL-28170 on ischemic insult was reversed by cotreatment with either class III-PI3K (phosphatidylinositol 3-kinase) inhibitor 3-methyladenine or lysosomal inhibitor chloroquine (chloroquine), suggesting that CAPN1 activation-mediated impairment of autophagic flux is crucial for cerebral ischemia-induced neuronal damage. Conclusions: The present study demonstrates for the first time that ischemia-induced CAPN1 activation impairs lysosomal function and suppresses autophagosome formation, which contribute to the accumulation of substrates and aggravate the ischemia-induced neuronal cell damage. Our work highlights the vital role of CAPN1 in the regulation of cerebral ischemia–mediated autophagy-lysosomal pathway defects and neuronal damage.

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