1,720,999 research outputs found
Human sperm functioning is related to the aquaporin-mediated water and hydrogen peroxide transport regulation
No full textAquaporins (AQPs) are transmembrane water channels and some of them are permeable in addition to water to other small solutes including hydrogen peroxide. The sperm cells of mammals and fishes express different AQPs, although there is no agreement in the literature on their localization. In humans, AQP3 and AQP11 are expressed mainly in the tail, AQP7 in the head and AQP8 in the midpiece. Thanks to the results of experiments with KO mice and to data obtained by comparing sub-fertile patients with normospermic subjects, the importance of AQPs for the normal functioning of sperms to ensure normal fertility emerged. AQP3, AQP7 and AQP11 appeared involved in the sperm volume regulation, a key role for fertility because osmoadaptation protect the sperm against a swelling and tail bending that could affect sperm motility. AQP8 seems to have a fundamental role in regulating the elimination of hydrogen peroxide, the most abundant reactive oxygen species (ROS), and therefore in the response to oxidative stress. In this review, the human AQPs expression, their localization and functions, as well as their relevance in normal fertility are discussed. To understand better the AQPs role in human sperm functionality, the results of studies obtained in other animal species were also considered
Hormonal control of subcutaneous adipose tissue aquaglyceroporins
No full textGlycerol metabolism in normal condition and in metabolic disorders like type-2 diabetes and obesity could depend at least in part on the transmembrane transport mechanisms of glycerol. Aquaglyceroporins (AQPs) are integral membrane protein belonging to the water channel proteins family (aquaporins) that are permeable to glycerol as well as water. Adipose tissue, the main source of plasma glycerol, expresses high levels of AQP7 but also AQP3, 9, 10. Recently, in adipose tissue was also found AQP11, whose permeability to glycerol is uncertain. However, the hormonal regulation of AQPs in the adipose tissue is not completely characterized. To this purpose we evaluated the effect of insulin, isoproterenol, thyroxin, dexamethasone in human isolated adipose tissue by real time RT-PCR. Immunocytochemistry was also performed to define the localization of the AQPs. Results showed that all the AQPs investigated are expressed in the human subcutaneous adipose tissue with a localization of AQP3,7 and 10 in both plasma membranes and in lipid droplets membranes, AQP9 mainly in the plasma membrane and AQP11 in the lipid droplets membrane. Generally, lipolytic and lipogenic stimuli differently affected the AQPs expression which depicts a complex situation involving, probably, different signaling pathway. These results and other recently described by the literature seem support the existence of different AQPs that under hormonal control and in pathological conditions can modify their expression levels and cellular localization, suggesting them as potential therapeutic targets in obesity and metabolic syndrome
AQP3 wound healing: is honey a new possible link?
No full textAQP3 plays an important role in hydration of mammalian skin epidermis, but also in the regulation of proliferation and differentiation of keratinocytes, being, therefore, important in wound healing. Since Biblical times, honey has been used in "folk medicine", and more recently, it has been successfully used on infections not responding to standard antiseptic and antibiotic therapy, in fact, it is well documented the honey production of H2O2. Etc..
Manuka honey induces apoptosis of epithelial cancer cells through aquaporin-3 and calcium signaling
No full textHoney is a natural product with a long use in traditional medicine and is well recognized to regulate different biological events. It is an important source of various biological or pharmacological molecules and, therefore, there is a strong interest to explore their properties. Evidence is growing that honey may have the potential to be an anticancer agent acting through several mechanisms. Here we observed for the first time in a cancer cell line a possible mechanism through which honey could induce an alteration in the intracellular reactive oxygen species and homeostatic balance of intracellular calcium concentration leading to cell death by apoptosis. This mechanism seems to be enhanced by manuka honey’s ability to maintain high H2 O2 permeability through aquaporin-3
Propolis induces AQP3 expression: A possible way of action in wound healing
Full text linkPropolis is the generic name of a complex of resinous compound collected by honeybees and it has been utilized for many years in folk medicine. As other products generated by honeybees (such as royal jelly, pollen, honey), propolis has great therapeutic properties, but very little scientific information is available. Therefore, this study was aimed at exploring the potential wound healing properties of propolis. To that end, we utilized an in vitro scratch wound healing model consisting of human immortalized keratinocytes. Our scratch wound data clearly demonstrated that propolis induced a pronounced increase in the wound repair abilities of keratinocytes. A cell migration assay showed that propolis stimulated keratinocytes to close the wound. We revealed the role of H2O2 as the main mediator of propolis regenerative properties. We showed that this extracellularly released H2O2 could pass across the plasma membrane through a specific aquaporin (i.e., AQP3) modulating intracellular responses. The data offer a biological characterization of propolis positive effects suggesting that propolis could also be utilized in wound treatment within clinical settings
Aquaporin-3 expression profile in malignant mesothelioma
No full textBackground & Objectives: Aquaporins regulate water transport in
normal and neoplastic cells. They also play a role in cell migration,
proliferation and adhesion. Preliminary data have shown AQP-1
upregulation in MM, but other aquaporin such as AQP-3 could
present disregulation and be used as potential therapeutic targets:
AQP-3 (an aquaglyceroporin expressed in the stratum corneum of
the skin) was found to be overexpressed in colorectal, cervical,
lung, oesophageal, gastric, skin and tongue (squamous) carcinomas
and in hepatocarcinomas.
Methods: Supported by preliminary biochemical results, a consecutive
series of ten MM samples was evaluated with immunohistochemistry
(Sigma Aldrich anti-AQP3 antibody) and AQP-3 expression
was compared with adjacent non-neoplastic mesothelium. We
evaluated only the positivity or negativity, regardless of the intensity
of the staining.
Results: Expression of AQP-3 was observed in 7 out of 10 cases, with a
membrane (62%) or cytoplasmic (25%) pattern of expression in up to
70% of MM cells, while expression in non-neoplastic mesothelium was
not significant. The only case of sarcomatoid malignant mesothelioma in
our series was found to be negative for AQP-3.
Conclusion: AQP-3 appears to be upregulated in 70% of our series of
MMs, with a prevalent expression on the membrane surface, where the
protein can play its natural role in water (and glycerol) exchange. The
cases where a cytoplasmatic pattern was observed, suggest us that protein
can play a pathogenetic role not only if correctly exported to the cellular
membrane, but also if accumulated in the cytoplasm
Sigma-1 receptor agonists acting on aquaporin-mediated h2o2 permeability: New tools for counteracting oxidative stress
No full textSigma1 Receptor (S1R) is involved in oxidative stress, since its activation is triggered by oxidative or endoplasmic reticulum stress. Since specific aquaporins (AQP), called peroxiporins, play a relevant role in controlling H2O2 permeability and ensure reactive oxygen species wasted during oxidative stress, we studied the effect of S1R modulators on AQP-dependent water and hydrogen peroxide permeability in the presence and in the absence of oxidative stress. Applying stopped-flow light scattering and fluorescent probe methods, water and hydrogen peroxide permeability in HeLa cells have been studied. Results evidenced that S1R agonists can restore water permeability in heat-stressed cells and the co-administration with a S1R antagonist totally counteracted the ability to restore the water permeability. Moreover, compounds were able to counteract the oxidative stress of HeLa cells specifically knocked down for S1R. Taken together these results support the hypothesis that the antioxidant mechanism is mediated by both S1R and AQP-mediated H2O2 permeability. The finding that small molecules can act on both S1R and AQP-mediated H2O2 permeability opens a new direction toward the identification of innovative drugs able to regulate cell survival during oxidative stress in pathologic conditions, such as cancer and degenerative diseases
Polyacrylic-Coated Solid Nanoparticles Increase the Aquaporin Permeability to Hydrogen Peroxide
No full textAquaporins (AQPs) allow the diffusion of hydrogen peroxide (H2O2) and act as ROS scavenging systems, which are important for controlling the redox state of cells. Recently, cerium oxide nanoparticles were found to increase the water and H2O2 permeability by modulating AQPs. To further analyze the action of nanoparticles (NPs) on AQP, we examined the effect of the NPs presenting different core compositions (CeO2, Gd2O3, Fe3O4, and TiO2), hydrodynamic sizes, and surface functionalization. The NPs produced an increase in H2O and H2O2 permeability as a general trend. The hydrodynamic sizes of the NPs in the range of 22–100 nm did not produce any significant effect. The chemical nature of the NPs’ core did not modify the effect and its intensity. On the other hand, the NPs’ functionalized surface plays a major role in influencing both water and H2O2 permeability. The results suggest that NPs can play a significant role in controlling oxidative stress in cells and might represent an innovative approach in the treatment of a number of pathologies associated with an increased oxidative status
Effects of creatine in a rat intestinal model of ischemia/reperfusion injury
No full textCreatine belongs to a buffering system of cellular ATP level and shows direct antioxidant activity. Our aim was to investigate if creatine could improve enterocytes antioxidant response and limit the oxidant injury induced by anoxia and reoxygenation. etc..
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