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16 pages, 5531 KiB

Open AccessArticle

Polyacrylic-Coated Solid Nanoparticles Increase the Aquaporin Permeability to Hydrogen Peroxide

by Giorgia Pellavio, Maria Paola Demichelis, Patrizia Sommi, Umberto Anselmi-Tamburini, Claudia Scotti and Umberto Laforenza

Int. J. Mol. Sci. 2024, 25(1), 372; https://doi.org/10.3390/ijms25010372 - 27 Dec 2023

Viewed by 718

Abstract

Aquaporins (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 H₂O [...] Read more.

Aquaporins (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. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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17 pages, 5972 KiB

Open AccessArticle

AQP1 in the Gastrointestinal Tract of Mice: Expression Pattern and Impact of AQP1 Knockout on Colonic Function

by Stefanie Volkart, Urs Kym, Olivier Braissant, Edgar Delgado-Eckert, Samer Al-Samir, Rebecca Angresius, Zihe Huo, Stefan Holland-Cunz and Stephanie J. Gros

Int. J. Mol. Sci. 2023, 24(4), 3616; https://doi.org/10.3390/ijms24043616 - 10 Feb 2023

Cited by 3 | Viewed by 1555

Abstract

Aquaporin 1 (AQP1) is one of thirteen known mammalian aquaporins. Its main function is the transport of water across cell membranes. Lately, a role of AQP has been attributed to other physiological and pathological functions including cell migration and peripheral pain perception. AQP1 [...] Read more.

Aquaporin 1 (AQP1) is one of thirteen known mammalian aquaporins. Its main function is the transport of water across cell membranes. Lately, a role of AQP has been attributed to other physiological and pathological functions including cell migration and peripheral pain perception. AQP1 has been found in several parts of the enteric nervous system, e.g., in the rat ileum and in the ovine duodenum. Its function in the intestine appears to be multifaceted and is still not completely understood. The aim of the study was to analyze the distribution and localization of AQP1 in the entire intestinal tract of mice. AQP1 expression was correlated with the hypoxic expression profile of the various intestinal segments, intestinal wall thickness and edema, as well as other aspects of colon function including the ability of mice to concentrate stools and their microbiome composition. AQP1 was found in a specific pattern in the serosa, the mucosa, and the enteric nervous system throughout the gastrointestinal tract. The highest amount of AQP1 in the gastrointestinal tract was found in the small intestine. AQP1 expression correlated with the expression profiles of hypoxia-dependent proteins such as HIF-1α and PGK1. Loss of AQP1 through knockout of AQP1 in these mice led to a reduced amount of bacteroidetes and firmicutes but an increased amount of the rest of the phyla, especially deferribacteres, proteobacteria, and verrucomicrobia. Although AQP-KO mice retained gastrointestinal function, distinct changes regarding the anatomy of the intestinal wall including intestinal wall thickness and edema were observed. Loss of AQP1 might interfere with the ability of the mice to concentrate their stool and it is associated with a significantly different composition of the of the bacterial stool microbiome. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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17 pages, 3391 KiB

Open AccessArticle

Increased Aquaporin-7 Expression Is Associated with Changes in Rat Brown Adipose Tissue Whitening in Obesity: Impact of Cold Exposure and Bariatric Surgery

by Gema Frühbeck, Leire Méndez-Giménez, Sara Becerril, Beatriz Ramírez, Ana Wenting Hernández-Pardos, Javier A. Cienfuegos, Víctor Valentí, Rafael Moncada, Victoria Catalán, Javier Gómez-Ambrosi, Inês V. da Silva, Graça Soveral and Amaia Rodríguez

Int. J. Mol. Sci. 2023, 24(4), 3412; https://doi.org/10.3390/ijms24043412 - 08 Feb 2023

Cited by 3 | Viewed by 1821

Abstract

Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in adipocytes, in the improvement of brown adipose tissue (BAT) whitening, a process whereby brown adipocytes differentiate into white-like unilocular cells, [...] Read more.

Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in adipocytes, in the improvement of brown adipose tissue (BAT) whitening, a process whereby brown adipocytes differentiate into white-like unilocular cells, after cold exposure or bariatric surgery in male Wistar rats with diet-induced obesity (DIO) (n = 229). DIO promoted BAT whitening, evidenced by increased BAT hypertrophy, steatosis and upregulation of the lipogenic factors Pparg2, Mogat2 and Dgat1. AQP7 was detected in BAT capillary endothelial cells and brown adipocytes, and its expression was upregulated by DIO. Interestingly, AQP7 gene and protein expressions were downregulated after cold exposure (4 °C) for 1 week or one month after sleeve gastrectomy in parallel to the improvement of BAT whitening. Moreover, Aqp7 mRNA expression was positively associated with transcripts of the lipogenic factors Pparg2, Mogat2 and Dgat1 and regulated by lipogenic (ghrelin) and lipolytic (isoproterenol and leptin) signals. Together, the upregulation of AQP7 in DIO might contribute to glycerol influx used for triacylglycerol synthesis in brown adipocytes, and hence, BAT whitening. This process is reversible by cold exposure and bariatric surgery, thereby suggesting the potential of targeting BAT AQP7 as an anti-obesity therapy. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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19 pages, 4644 KiB

Open AccessArticle

Wheat TaTIP4;1 Confers Enhanced Tolerance to Drought, Salt and Osmotic Stress in Arabidopsis and Rice

by Yan Wang, Yaqi Zhang, Yinchao An, Jingyuan Wu, Shibin He, Lirong Sun and Fushun Hao

Int. J. Mol. Sci. 2022, 23(4), 2085; https://doi.org/10.3390/ijms23042085 - 14 Feb 2022

Cited by 10 | Viewed by 2225

Abstract

Tonoplast aquaporins (intrinsic proteins, TIPs) have been indicated to play important roles in plant tolerance to water deficit and salinity. However, the functions of wheat TIPs in response to the stresses are largely unknown. In this study, we observed that transgenic plants overexpressing [...] Read more.

Tonoplast aquaporins (intrinsic proteins, TIPs) have been indicated to play important roles in plant tolerance to water deficit and salinity. However, the functions of wheat TIPs in response to the stresses are largely unknown. In this study, we observed that transgenic plants overexpressing wheat TaTIP4;1 in Arabidopsis and rice displayed clearly enhanced seed germination and seedling growth under drought, salt and osmotic stress. Compared with wild type plants, Arabidopsis and rice overexpression lines had heightened water contents, reduced leaf water loss, lowered levels of Na⁺, Na⁺/K⁺, H₂O₂ and malondialdehyde, and improved activities of catalase and/or superoxide dismutase, and increased accumulation of proline under drought, salinity and/or osmotic stresses. Moreover, the expression levels of multiple drought responsive genes clearly elevated upon water dehydration, and the transcription of some salt responsive genes was markedly induced by NaCl treatment in the overexpression lines. Also, the yeast cells containing TaTIP4;1 showed increased tolerance to NaCl and mannitol, and mutation in one of three serines of TaTIP4;1 caused decreased tolerance to the two stresses. These results suggest that TaTIP4;1 serves as an essential positive regulator of seed germination and seedling growth under drought, salt and/or osmotic stress through impacting water relations, ROS balance, the accumulation of Na⁺ and proline, and stimulating the expression of dozens of stress responsive genes in Arabidopsis and rice. Phosphorylation may modulate the activity of TaTIP4;1. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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31 pages, 177670 KiB

Open AccessArticle

Aurora Kinase A Is Involved in Controlling the Localization of Aquaporin-2 in Renal Principal Cells

by Sandrine Baltzer, Timur Bulatov, Christopher Schmied, Andreas Krämer, Benedict-Tilman Berger, Andreas Oder, Ryan Walker-Gray, Christin Kuschke, Kerstin Zühlke, Jenny Eichhorst, Martin Lehmann, Stefan Knapp, John Weston, Jens Peter von Kries, Roderich D. Süssmuth and Enno Klussmann

Int. J. Mol. Sci. 2022, 23(2), 763; https://doi.org/10.3390/ijms23020763 - 11 Jan 2022

Cited by 3 | Viewed by 3657

Abstract

The cAMP-dependent aquaporin-2 (AQP2) redistribution from intracellular vesicles into the plasma membrane of renal collecting duct principal cells induces water reabsorption and fine-tunes body water homeostasis. However, the mechanisms controlling the localization of AQP2 are not understood in detail. Using immortalized mouse medullary [...] Read more.

The cAMP-dependent aquaporin-2 (AQP2) redistribution from intracellular vesicles into the plasma membrane of renal collecting duct principal cells induces water reabsorption and fine-tunes body water homeostasis. However, the mechanisms controlling the localization of AQP2 are not understood in detail. Using immortalized mouse medullary collecting duct (MCD4) and primary rat inner medullary collecting duct (IMCD) cells as model systems, we here discovered a key regulatory role of Aurora kinase A (AURKA) in the control of AQP2. The AURKA-selective inhibitor Aurora-A inhibitor I and novel derivatives as well as a structurally different inhibitor, Alisertib, prevented the cAMP-induced redistribution of AQP2. Aurora-A inhibitor I led to a depolymerization of actin stress fibers, which serve as tracks for the translocation of AQP2-bearing vesicles to the plasma membrane. The phosphorylation of cofilin-1 (CFL1) inactivates the actin-depolymerizing function of CFL1. Aurora-A inhibitor I decreased the CFL1 phosphorylation, accounting for the removal of the actin stress fibers and the inhibition of the redistribution of AQP2. Surprisingly, Alisertib caused an increase in actin stress fibers and did not affect CFL1 phosphorylation, indicating that AURKA exerts its control over AQP2 through different mechanisms. An involvement of AURKA and CFL1 in the control of the localization of AQP2 was hitherto unknown. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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7 pages, 1501 KiB

Open AccessCommunication

Involvement of Reactive Oxygen Species in ABA-Induced Increase in Hydraulic Conductivity and Aquaporin Abundance

by Guzel Sharipova, Ruslan Ivanov, Dmitriy Veselov, Guzel Akhiyarova, Maria Shishova, Tatyana Nuzhnaya and Guzel Kudoyarova

Int. J. Mol. Sci. 2021, 22(17), 9144; https://doi.org/10.3390/ijms22179144 - 24 Aug 2021

Cited by 6 | Viewed by 1720

Abstract

The role of reactive oxygen species (ROS) in ABA-induced increase in hydraulic conductivity was hypothesized to be dependent on an increase in aquaporin water channel (AQP) abundance. Single ABA application or its combination with ROS manipulators (ROS scavenger ascorbic acid and NADPH oxidase [...] Read more.

The role of reactive oxygen species (ROS) in ABA-induced increase in hydraulic conductivity was hypothesized to be dependent on an increase in aquaporin water channel (AQP) abundance. Single ABA application or its combination with ROS manipulators (ROS scavenger ascorbic acid and NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI)) were studied on detached roots of barley plants. We measured the osmotically driven flow rate of xylem sap and calculated root hydraulic conductivity. In parallel, immunolocalization of ABA and HvPIP2;2 AQPs was performed with corresponding specific antibodies. ABA treatment increased the flow rate of xylem, root hydraulic conductivity and immunostaining for ABA and HvPIP2;2, while the addition of antioxidants prevented the effects of this hormone. The obtained results confirmed the involvement of ROS in ABA effect on hydraulic conductivity, in particular, the importance of H₂O₂ production by ABA-treated plants for the effect of this hormone on AQP abundance. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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Review

Jump to: Research

12 pages, 1917 KiB

Open AccessReview

Aquaporins in the Cornea

by Samuel Melnyk and Wendy B. Bollag

Int. J. Mol. Sci. 2024, 25(7), 3748; https://doi.org/10.3390/ijms25073748 - 28 Mar 2024

Viewed by 523

Abstract

The cornea is an avascular, transparent tissue that allows light to enter the visual system. Accurate vision requires proper maintenance of the cornea’s integrity and structure. Due to its exposure to the external environment, the cornea is prone to injury and must undergo [...] Read more.

The cornea is an avascular, transparent tissue that allows light to enter the visual system. Accurate vision requires proper maintenance of the cornea’s integrity and structure. Due to its exposure to the external environment, the cornea is prone to injury and must undergo proper wound healing to restore vision. Aquaporins (AQPs) are a family of water channels important for passive water transport and, in some family members, the transport of other small molecules; AQPs are expressed in all layers of the cornea. Although their functions as water channels are well established, the direct function of AQPs in the cornea is still being determined and is the focus of this review. AQPs, primarily AQP1, AQP3, and AQP5, have been found to play an important role in maintaining water homeostasis, the corneal structure in relation to proper hydration, and stress responses, as well as wound healing in all layers of the cornea. Due to their many functions in the cornea, the identification of drug targets that modulate the expression of AQPs in the cornea could be beneficial to promote corneal wound healing and restore proper function of this tissue crucial for vision. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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16 pages, 701 KiB

Open AccessReview

The Role of Aquaporins in Plant Growth under Conditions of Oxygen Deficiency

by Guzel Kudoyarova, Dmitriy Veselov, Vladislav Yemelyanov and Maria Shishova

Int. J. Mol. Sci. 2022, 23(17), 10159; https://doi.org/10.3390/ijms231710159 - 05 Sep 2022

Cited by 6 | Viewed by 1847

Abstract

Plants frequently experience hypoxia due to flooding caused by intensive rainfall or irrigation, when they are partially or completely submerged under a layer of water. In the latter case, some resistant plants implement a hypoxia avoidance strategy by accelerating shoot elongation, which allows [...] Read more.

Plants frequently experience hypoxia due to flooding caused by intensive rainfall or irrigation, when they are partially or completely submerged under a layer of water. In the latter case, some resistant plants implement a hypoxia avoidance strategy by accelerating shoot elongation, which allows lifting their leaves above the water surface. This strategy is achieved due to increased water uptake by shoot cells through water channels (aquaporins, AQPs). It remains a puzzle how an increased flow of water through aquaporins into the cells of submerged shoots can be achieved, while it is well known that hypoxia inhibits the activity of aquaporins. In this review, we summarize the literature data on the mechanisms that are likely to compensate for the decline in aquaporin activity under hypoxic conditions, providing increased water entry into cells and accelerated shoot elongation. These mechanisms include changes in the expression of genes encoding aquaporins, as well as processes that occur at the post-transcriptional level. We also discuss the involvement of hormones, whose concentration changes in submerged plants, in the control of aquaporin activity. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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29 pages, 5597 KiB

Open AccessReview

Insight into the Mammalian Aquaporin Interactome

by Susanna Törnroth-Horsefield, Clara Chivasso, Helin Strandberg, Claudia D’Agostino, Carla V. T. O’Neale, Kevin L. Schey and Christine Delporte

Int. J. Mol. Sci. 2022, 23(17), 9615; https://doi.org/10.3390/ijms23179615 - 25 Aug 2022

Cited by 10 | Viewed by 3547

Abstract

Aquaporins (AQPs) are a family of transmembrane water channels expressed in all living organisms. AQPs facilitate osmotically driven water flux across biological membranes and, in some cases, the movement of small molecules (such as glycerol, urea, CO₂, NH₃, H [...] Read more.

Aquaporins (AQPs) are a family of transmembrane water channels expressed in all living organisms. AQPs facilitate osmotically driven water flux across biological membranes and, in some cases, the movement of small molecules (such as glycerol, urea, CO₂, NH₃, H₂O₂). Protein–protein interactions play essential roles in protein regulation and function. This review provides a comprehensive overview of the current knowledge of the AQP interactomes and addresses the molecular basis and functional significance of these protein–protein interactions in health and diseases. Targeting AQP interactomes may offer new therapeutic avenues as targeting individual AQPs remains challenging despite intense efforts. Full article

(This article belongs to the Special Issue Recent Advances in Aquaporins)

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