Autoradiographic analysis and regulation of angiotensin receptor subtypes AT4, AT1, and AT(1—7) in the kidney

2001 ◽  
Vol 281 (5) ◽  
pp. F936-F947 ◽  
Author(s):  
Rajash K. Handa ◽  
Shelly E. Handa ◽  
Monica K. S. Elgemark

Receptor autoradiography revealed that angiotensin AT4 receptors were abundantly expressed in normal mammalian (mouse, rat, gerbil, guinea pig, rabbit) and avian (sparrow, chicken, turkey) kidneys and were more extensively distributed than previously reported (including proximal and distal segments of the nephron, interstitium, renal artery, vein, and ureter). Angiotensin AT4 receptors were generally found to be more abundant than angiotensin AT1 receptors in mammalian kidneys, whereas angiotensin AT(1—7) receptors were not detected in either mammalian or avian kidneys. Rats subjected to various chronic treatments were found to preferentially decrease kidney AT4 receptor density (furosemide, puromycin aminonucleoside, nitro-l-arginine methyl ester), decrease kidney AT1 receptor density (bilateral ureteral obstruction), or increase kidney AT1 receptor distribution in the inner medulla (water diuresis). These results indicate that the AT4 receptor can be expressed in numerous cell types within the normal kidney of several species. Furthermore, several models of renal dysfunction and injury have been identified that selectively alter kidney AT4 density and may potentially aid in elucidating the role of this novel angiotensin receptor system in renal function.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Mariagrazia Valentini ◽  
Alessia Piermattei ◽  
Gabriele Di Sante ◽  
Giuseppe Migliara ◽  
Giovanni Delogu ◽  
...  

A close relationship exists between gut microbiota and immune responses. An imbalance of this relationship can determine local and systemic immune diseases. In fact the immune system plays an essential role in maintaining the homeostasis with the microbiota that normally resides in the gut, while, at the same time, the gut microbiota influences the immune system, modulating number and function of effector and regulatory T cells. To achieve this aim, mutual regulation between immune system and microbiota is achieved through several mechanisms, including the engagement of toll-like receptors (TLRs), pathogen-specific receptors expressed on numerous cell types. TLRs are able to recognize ligands from commensal or pathogen microbiota to maintain the tolerance or trigger the immune response. In this review, we summarize the latest evidences about the role of TLRs expressed in adaptive T cells, to understand how the immune system promotes intestinal homeostasis, fights invasion by pathogens, and is modulated by the intestinal microbiota.


Author(s):  
David A. Lovejoy ◽  
Téa Pavlović

AbstractIn humans, the teneurin gene family consists of four highly conserved paralogous genes that are the result of early vertebrate gene duplications arising from a gene introduced into multicellular organisms from a bacterial ancestor. In vertebrates and humans, the teneurins have become integrated into a number of critical physiological systems including several aspects of reproductive physiology. Structurally complex, these genes possess a sequence in their terminal exon that encodes for a bioactive peptide sequence termed the ‘teneurin C-terminal associated peptide’ (TCAP). The teneurin/TCAP protein forms an intercellular adhesive unit with its receptor, latrophilin, an Adhesion family G-protein coupled receptor. It is present in numerous cell types and has been implicated in gamete migration and gonadal morphology. Moreover, TCAP is highly effective at reducing the corticotropin-releasing factor (CRF) stress response. As a result, TCAP may also play a role in regulating the stress-associated inhibition of reproduction. In addition, the teneurins and TCAP have been implicated in tumorigenesis associated with reproductive tissues. Therefore, the teneurin/TCAP system may offer clinicians a novel biomarker system upon which to diagnose some reproductive pathologies.


2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Kirsty M. Danielson ◽  
Saumya Das

Extracellular vesicles (EV), including exosomes, microvesicles and apoptotic bodies, are released from numerous cell types and are involved in intercellular communication, physiological functions and the pathology of disease. They have been shown to carry and transfer a wide range of cargo including proteins, lipids and nucleic acids. The role of EVs in cardiac physiology and heart disease is an emerging field that has produced intriguing findings in recent years. This review will outline what is currently known about EVs in the cardiovascular system, including cellular origins, functional roles and utility as biomarkers and potential therapeutics.


2021 ◽  
pp. 1-9
Author(s):  
Shufen Zhang ◽  
Deshu Shang ◽  
Han Shi ◽  
Weiyu Teng ◽  
Li Tian

<b><i>Background:</i></b> Astrocytes are the most numerous cell types within the central nervous system, and many efforts have been put into determining the exact role of astrocytes in neuroprotection and repair after ischemic stroke. Although numerous studies have been done in recent years, there is still no thorough understanding of the exact function of astrocytes in the whole course of the stroke. <b><i>Summary:</i></b> According to the recent literature, there are many structures and factors that play important roles in the process of ischemic stroke, among which blood-brain barrier, various growth factors, gap junctions, AQP4, and glial scars have been studied most comprehensively, and all these factors are closely related to astrocytes. The role of astrocytes in ischemic stroke, therefore, can be analyzed more comprehensively. <b><i>Key Message:</i></b> The present review mainly summarized the current knowledge about astrocytes and their potential roles after ischemic stroke.


2006 ◽  
Vol 53 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Agnieszka Borowiec ◽  
Katarzyna Lechward ◽  
Kinga Tkacz-Stachowska ◽  
Andrzej C Składanowski

Adenosine is a product of complete dephosphorylation of adenine nucleotides which takes place in various compartments of the cell. This nucleoside is a significant signal molecule engaged in regulation of physiology and modulation of the function of numerous cell types (i.e. neurons, platelets, neutrophils, mast cells and smooth muscle cells in bronchi and vasculature, myocytes etc.). As part a of purinergic signaling system, adenosine mediates neurotransmission, conduction, secretion, vasodilation, proliferation and cell death. Most of the effects of adenosine help to protect cells and tissues during stress conditions such as ischemia or anoxia. Adenosine receptors and nucleoside transporters are targets for potential drugs in many pathophysiological situations. The adenosine-producing system in vertebrates involves a cascade dephosphorylating ATP and ending with 5'-nucleotidase (EC 3.1.3.5) localized either on the membrane or inside the cell. In this paper the cytoplasmic variants of 5'-nucleotidase are broadly characterized as well as their clinical relevance. The role of AMP-selective 5'-nucleotidase (cN-I) in the heart, skeletal muscle and brain is highlighted. cN-I action is crucial during ischemia and important for the efficacy of some nucleoside-based drugs and in the regulation of the substrate pool for nucleic acids synthesis. Inhibitors used in studying the roles of cytoplasmic and membrane-bound 5'-nucleotidases are also described.


Hypertension ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 408-414 ◽  
Author(s):  
Zemin Cao ◽  
Rachael Dean ◽  
Leonard Wu ◽  
David Casley ◽  
Mark E. Cooper

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1218
Author(s):  
Antonio Filippini ◽  
Alessio D’Alessio

Caveolae are flask-shaped invaginations of the plasma membrane found in numerous cell types and are particularly abundant in endothelial cells and adipocytes. The lipid composition of caveolae largely matches that of lipid rafts microdomains that are particularly enriched in cholesterol, sphingomyelin, glycosphingolipids, and saturated fatty acids. Unlike lipid rafts, whose existence remains quite elusive in living cells, caveolae can be clearly distinguished by electron microscope. Despite their similar composition and the sharing of some functions, lipid rafts appear more heterogeneous in terms of size and are more dynamic than caveolae. Following the discovery of caveolin-1, the first molecular marker as well as the unique scaffolding protein of caveolae, we have witnessed a remarkable increase in studies aimed at investigating the role of these organelles in cell functions and human disease. The goal of this review is to discuss the most recent studies related to the role of caveolae and caveolins in endothelial cells. We first recapitulate the major embryological processes leading to the formation of the vascular tree. We next discuss the contribution of caveolins and cavins to membrane biogenesis and cell response to extracellular stimuli. We also address how caveolae and caveolins control endothelial cell metabolism, a central mechanism involved in migration proliferation and angiogenesis. Finally, as regards the emergency caused by COVID-19, we propose to study the caveolar platform as a potential target to block virus entry into endothelial cells.


Platelet-activating factor (alkylacetylglycerolphosphocholine; PAF) is a potent signaling phospholipid which has been found in numerous cell types in every physiological system studied to date. In reproduction, PAF is found to have a variety of roles, for example: in ovulation, sperm function, and early preimplantation development. The goal of this mini review is to highlight PAF’s synthesis, mechanism of action and its functional role in sperm physiology. PAF functions via a G protein coupled receptor mediated pathway, which ultimately increases intracellular calcium levels to enhance sperm motility required for fertilization. Exogenous PAF was also found to increase fertilization potential of spermatozoa in cases of non-male factor infertility. Finally, the mini review explores various lifestyle factors that could potentially affect PAF levels and fertility.


Author(s):  
W.T. Gunning ◽  
M.R. Marino ◽  
M.S. Babcock ◽  
G.D. Stoner

The role of calcium in modulating cellular replication and differentiation has been described for various cell types. In the present study, the effects of Ca++ on the growth and differentiation of cultured rat esophageal epithelial cells was investigated.Epithelial cells were isolated from esophagi taken from 8 week-old male CDF rats by the enzymatic dissociation method of Kaighn. The cells were cultured in PFMR-4 medium supplemented with 0.25 mg/ml dialyzed fetal bovine serum, 5 ng/ml epidermal growth factor, 10-6 M hydrocortisone 10-6 M phosphoethanolamine, 10-6 M ethanolamine, 5 pg/ml insulin, 5 ng/ml transferrin, 10 ng/ml cholera toxin and 50 ng/ml garamycin at 36.5°C in a humidified atmosphere of 3% CO2 in air. At weekly intervals, the cells were subcultured with a solution containing 1% polyvinylpyrrolidone, 0.01% EGTA, and 0.05% trypsin. After various passages, the replication rate of the cells in PFMR-4 medium containing from 10-6 M to 10-3 M Ca++ was determined using a clonal growth assay.


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