scholarly journals Tissue Distribution of the Readthrough Isoform of AQP4 Reveals a Dual Role of AQP4ex Limited to CNS

2020 ◽  
Vol 21 (4) ◽  
pp. 1531
Author(s):  
Claudia Palazzo ◽  
Pasqua Abbrescia ◽  
Onofrio Valente ◽  
Grazia Paola Nicchia ◽  
Shervin Banitalebi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Water Channel ◽  
Dual Role ◽  
Immunogold Electron Microscopy ◽  
Peripheral Tissues ◽  
Protein Levels ◽  
Translational Readthrough ◽  
The Central Nervous System ◽  
Astrocytic Endfeet

Translational readthrough (TRT) of aquaporin-4 (AQP4) has remarkably expanded the importance of this new post-transcriptional mechanism, as well as the regulation potential of AQP4. The TRT isoform of AQP4, named AQP4ex, is central for both AQP4 polarization and water channel activity in the central nervous system (CNS). Here we evaluate the relevance of the TRT mechanism by analyzing whether AQP4ex is also expressed in peripheral tissues and whether the expression of AQP4ex is necessary for its polarized expression as it occurs in perivascular astrocyte processes. To this purpose, AQP4ex null mice were used, and analysis was performed by immunolocalization and immunoblot. The results demonstrate that AQP4ex is expressed in kidney, stomach, trachea and skeletal muscle with the same localization pattern as the canonical AQP4 isoforms. AQP4ex protein levels vary from 6% to about 13% of the total AQP4 protein levels in peripheral tissues. Immunogold electron microscopy experiments demonstrated the localization of AQP4ex at the astrocytic endfeet, and experiments conducted on AQP4ex null mice CNS confirmed that the expression of AQP4ex is necessary for anchoring of the perivascular AQP4. Without the readthrough isoform, AQP4 assemblies are mis-localized, being uniformly distributed on the astrocyte processes facing the neuropile. No alteration of AQP4 polarization was found in AQP4ex null kidney, stomach, trachea or skeletal muscle, suggesting that AQP4ex does not have a role for proper membrane localization of AQP4 in peripheral tissues. We conclude that a dual role for AQP4ex is limited to the CNS.

scholarly journals The Role of Morphine in Animal Models of Human Cancer: Does Morphine Promote or Inhibit the Tumor Growth?

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Sabrina Bimonte ◽  
Antonio Barbieri ◽  
Giuseppe Palma ◽  
Claudio Arra
Keyword(s):  
Tumor Growth ◽  
Human Cancer ◽  
Primary Tumour ◽  
Cancer Cell Growth ◽  
Peripheral Tissues ◽  
Patients With Cancer ◽  
Relieve Pain ◽  
Pain And Suffering ◽  
The Central Nervous System

Morphine, a highly potent analgesic agent, is widely used to relieve pain and suffering of patients with cancer. Additionally, it has been reported that morphine is important in the regulation of cancerous tissue. Morphine relieves pain by acting directly on the central nervous system, although its activities on peripheral tissues are responsible for many adverse side effects. For these reasons, it is very important also to understand the role of morphine in cancer treatment. The published literature reporting the effect of morphine on tumor growth presents some discrepancies, with reports suggesting that morphine may either promote or inhibit the tumor growth. It has been also demonstrated that morphine modulates angiogenesis which is important for primary tumour growth, invasiveness, and the development of metastasis. This review will focus on the latest findings on the role of morphine in the regulation of cancer cell growth and angiogenesis.

scholarly journals Issues About the Physiological Functions of Prolyl Oligopeptidase Based on Its Discordant Spatial Association With Substrates and Inconsistencies Among mRNA, Protein Levels, and Enzymatic Activity

2009 ◽  
Vol 57 (9) ◽  
pp. 831-848 ◽  
Author(s):  
Timo T. Myöhänen ◽  
J. Arturo García-Horsman ◽  
Jofre Tenorio-Laranga ◽  
Pekka T. Männistö
Keyword(s):  
Spatial Association ◽  
Physiological Role ◽  
Prolyl Oligopeptidase ◽  
Protein Levels ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
The Central Nervous System ◽  
Basic Studies ◽  
Catalytic Functions

Prolyl oligopeptidase (POP) is a serine endopeptidase that hydrolyses proline-containing peptides shorter than 30 amino acids. POP may be associated with cognitive functions, possibly via the cleavage of neuropeptides. Recent studies have also suggested novel non-hydrolytic and non-catalytic functions for POP. Moreover, POP has also been proposed as a regulator of inositol 1,4,5-triphosphate signaling and several other functions such as cell proliferation and differentiation, as well as signal transduction in the central nervous system, and it is suspected to be involved in pathological conditions such as Parkinson's and Alzheimer's diseases and cancer. POP inhibitors have been developed to restore the depleted neuropeptide levels encountered in aging or in neurodegenerative disorders. These compounds have shown some antiamnesic effects in animal models. However, the mechanisms of these hypothesized actions are still far from clear. Moreover, the physiological role of POP has remained unknown, and a lack of basic studies, including its distribution, is obvious. The aim of this review is to gather information about POP and to propose some novel roles for this enzyme based on its distribution and its discordant spatial association with its best known substrates.

Enhanced pressor responses to ICV vasopressin after pretreatment with oxytocin

1994 ◽  
Vol 266 (2) ◽  
pp. R592-R598 ◽  
Author(s):  
P. Poulin ◽  
A. Komulainen ◽  
Y. Takahashi ◽  
Q. J. Pittman
Keyword(s):  
Skeletal Muscle ◽  
Cardiovascular Effects ◽  
Intracerebroventricular Injection ◽  
Central Administration ◽  
Cardiovascular Actions ◽  
Pressor Responses ◽  
The Central Nervous System ◽  
Dose Dependent ◽  
Higher Doses

The role of oxytocin (OT) in the modulation of arginine vasopressin (AVP)-induced cardiovascular effects within the central nervous system was investigated in urethan-anesthetized rats. Intracerebroventricular injection of AVP (1-10 pmol) produced dose-dependent increases in mean arterial pressure (MAP) and heart rate (HR). These responses were enhanced in rats pretreated 24 h earlier with OT (10 pmol icv). The enhanced cardiovascular effects of AVP in OT-pretreated animals were dose dependent, blocked by the V1 antagonist d(CH2)5Tyr(Me)AVP, not evoked by OT alone, and occurred in the absence of changes in basal (nonstimulated) MAP and HR. In addition, central administration of AVP in OT-pretreated rats, but not in saline-pretreated controls, caused dose-dependent oscillations of the MAP and HR responses and, at higher doses, death of the animals. The enhanced cardiovascular actions of centrally injected AVP in OT-pretreated rats do not appear to be secondary to skeletal muscle contractions or the result of cerebral ischemia. Our data point to an interaction between the central oxytocinergic and vasopressinergic systems in cardiovascular control.

Dual role of delta-like 1 homolog (DLK1) in skeletal muscle development and adult muscle regeneration

Development ◽  
2013 ◽  
Vol 140 (18) ◽  
pp. 3743-3753 ◽  
Author(s):  
D. C. Andersen ◽  
J. Laborda ◽  
V. Baladron ◽  
M. Kassem ◽  
S. P. Sheikh ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Regeneration ◽  
Muscle Development ◽  
Dual Role ◽  
Skeletal Muscle Development ◽  
Adult Muscle

Adrenodemedullation activates the Ca2+-dependent proteolysis in soleus muscles from rats exposed to cold

2017 ◽  
Vol 122 (2) ◽  
pp. 317-326 ◽  
Author(s):  
L. H. Manfredi ◽  
D. Lustrino ◽  
J. Machado ◽  
W. A. Silveira ◽  
N. M. Zanon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adrenal Medulla ◽  
Cold Exposure ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Calpain Inhibitor ◽  
Skeletal Muscle Protein ◽  
Protein Levels ◽  
Muscle Protein Metabolism

Previous studies have shown that catecholamines in vivo and in vitro inhibit the activity of Ca2+-dependent proteolysis in skeletal muscles under basal conditions. In the present study we sought to investigate the role of catecholamines in regulating the Ca2+-dependent proteolysis in soleus and extensor digitorum longus (EDL) muscles from rats acutely exposed to cold. Overall proteolysis, the activity of proteolytic systems, protein levels and gene expression of different components of the calpain system were investigated in rats submitted to adrenodemedullation (ADMX) and exposed to cold for 24 h. ADMX drastically reduced plasma epinephrine and promoted an additional increase in the overall proteolysis, which was already increased by cold exposure. The rise in the rate of protein degradation in soleus muscles from adrenodemedullated cold-exposed rats was caused by the high activity of the Ca2+-dependent proteolysis, which was associated with the generation of a 145-kDa cleaved α-fodrin fragment, a typical calpain substrate, and lower protein levels and mRNA expression of calpastatin, the endogenous calpain inhibitor. Unlike that observed for soleus muscles, the cold-induced muscle proteolysis in EDL was not affected by ADMX. In isolated soleus muscle, clenbuterol, a selective β2-adrenoceptor agonist, reduced the basal Ca2+-dependent proteolysis and completely abolished the activation of this pathway by the cholinergic agonist carbachol. These data suggest that catecholamines released from the adrenal medulla inhibit cold-induced protein breakdown in soleus, and this antiproteolytic effect on the Ca2+-dependent proteolytic system is apparently mediated through expression of calpastatin, which leads to suppression of calpain activation. NEW & NOTEWORTHY Although many effects of the sympathetic nervous system on muscle physiology are known, the role of catecholamines in skeletal muscle protein metabolism has been scarcely studied. We suggest that catecholamines released from adrenal medulla may be of particular importance for restraining the activation of the Ca2+-dependent proteolysis in soleus muscles during acute cold exposure. This finding helps us to understand the adaptive changes that occur in skeletal muscle protein metabolism during cold stress.

scholarly journals Muscle-specific overexpression of lipoprotein lipase in transgenic mice results in increased α-tocopherol levels in skeletal muscle

1996 ◽  
Vol 318 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Wolfgang SATTLER ◽  
Sanja LEVAK-FRANK ◽  
Herbert RADNER ◽  
Gerhard M. KOSTNER ◽  
Rudolf ZECHNER
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Transgenic Mice ◽  
Cardiac Muscle ◽  
Lipoprotein Lipase ◽  
Excellent Correlation ◽  
Peripheral Tissues ◽  
Tissue Specific

Lipoprotein lipase (LPL) has been implicated in the delivery of chylomicron-located α-tocopherol (α-TocH) to peripheral tissues. To investigate the role of LPL in the cellular uptake of α-TocH in peripheral tissue in vivo, three lines of transgenic mice [mouse creatine kinase- (MCK) L, MCK-M and MCK-H] expressing various amounts of human LPL were compared with regard to α-TocH levels in plasma, skeletal muscle, cardiac muscle, adipose tissue and brain. Depending on the copy number of the transgene, LPL activity was increased 3- to 27-fold in skeletal muscle and 1.3- to 3.7-fold in cardiac muscle. The intracellular levels of α-TocH in skeletal muscle were significantly increased in MCK-M and MCK-H animals and correlated highly with the tissue-specific LPL activity (r = 0.998). The highest levels were observed in MCK-H (21.4 nmol/g) followed by MCK-M (13.3 nmol/g) and MCK-L (8.2 nmol/g) animals when compared with control mice (7.3 nmol/g). Excellent correlation was also observed between intracellular α-TocH and non-esterified fatty acid (NEFA) levels (r = 0.998). Although LPL activities in cardiac muscle were also increased in the transgenic mouse lines, α-TocH concentrations in the heart remained unchanged. Similarly, α-TocH levels in plasma, adipose tissue and brain were unaffected by the tissue specific overexpression of LPL in muscle. The transgenic model presented in this report provides evidence that the uptake of α-TocH in muscle is directly dependent on the level of LPL expression in vivo. Increased intracellular α-TocH concentrations with increased triglyceride lipolysis and NEFA uptake might protect the myocyte from oxidative damage during increased β-oxidation.

scholarly journals Interrelation of Oxidative Stress and Inflammation in Neurodegenerative Disease: Role of TNF

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Roman Fischer ◽  
Olaf Maier
Keyword(s):  
Oxidative Stress ◽  
Neurodegenerative Diseases ◽  
Neurodegenerative Disease ◽  
Tissue Regeneration ◽  
Neuronal Damage ◽  
Dual Role ◽  
Cytokine Tumor Necrosis Factor ◽  
The Central Nervous System ◽  
Necrosis Factor

Neuroinflammation and mitochondrial dysfunction are common features of chronic neurodegenerative diseases of the central nervous system. Both conditions can lead to increased oxidative stress by excessive release of harmful reactive oxygen and nitrogen species (ROS and RNS), which further promote neuronal damage and subsequent inflammation resulting in a feed-forward loop of neurodegeneration. The cytokine tumor necrosis factor (TNF), a master regulator of the immune system, plays an important role in the propagation of inflammation due to the activation and recruitment of immune cells via its receptor TNF receptor 1 (TNFR1). Moreover, TNFR1 can directly induce oxidative stress by the activation of ROS and RNS producing enzymes. Both TNF-induced oxidative stress and inflammation interact and cooperate to promote neurodegeneration. However, TNF plays a dual role in neurodegenerative disease, since stimulation via its second receptor, TNFR2, is neuroprotective and promotes tissue regeneration. Here we review the interrelation of oxidative stress and inflammation in the two major chronic neurodegenerative diseases, Alzheimer’s and Parkinson’s disease, and discuss the dual role of TNF in promoting neurodegeneration and tissue regeneration via its two receptors.

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