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Sepsis associated Acute kidney injury (AKI) is a common clinical syndrome characterized by suddenly decreased in renal function and urinary volume. This study was designed to investigate the role of Aquaporin 1 (AQP1) and P53 in the development of sepsis-induced AKI and their potential regulatorymechanisms. Firstly, transcriptome sequencing analysis of mice kidney showed AQP1 expression was reduced and P53 expression was elevated in Cecal ligation and puncture (CLP)- induced AKI compared with controls. Bioinformatics confirmed that AQP1 expression was remarkably decreased and P53 expression was obviously elevated in renal tissues or peripheral blood of septic AKI patients. Moreover, we found in vivo experiments that AQP1mRNA levels were dramatically decreased and P53mRNA significantly increased following the increased expression of inflammation, apoptosis, fibrosis, NGAL and KIM-1 at various periods in septic AKI. Meanwhile, AQP1 and P53 protein levels increased significantly first and then decreased gradually in kidney tissue and serum of rats in different stages of septic AKI. Most importantly, in vivo and vitro experiments demonstrated that silencing of AQP1 greatly exacerbates renal or cellular injury by upregulating P53 expression promoting inflammatory response, apoptosis and fibrosis. Overexpression of AQP1 prevented the elevation of inflammation, apoptosis and fibrosis by down-regulating P53 expression in Lipopolysaccharide (LPS)-induced AKI or HK-2 cells. Therefore, our results suggested that AQP1 plays a protective role in modulating AKI and can attenuate inflammatory response, apoptosis and fibrosis via downregulating P53 in septic AKI or LPS-induced HK-2cells. The pharmacological targeting of AQP1mediated P53 expressionmight be identified as potential targets for the early treatment of septic AKI. [ABSTRACT FROM AUTHOR]

Heatstroke induces fluid loss and electrolyte abnormalities owing to high ambient temperature (AT) and relative humidity (RH). Aquaporin 1 (AQP1) is a key protein for water homeostasis; however, its role in heatstroke remains unclear. This study examines endothelial AQP1 in Tie2-Cre/LNL-AQP1 double transgenic (dTG) mice with upregulated Aqp1 in endothelial cells. For experimental heatstroke, mice were exposed to 41 °C AT and >99% RH. Blood, brain, kidney, and liver samples were collected 24 h later. Blood was analyzed for electrolytes and tissue damage markers, and organs were examined using morphological and immunohistological staining for 3-nitrotyrosine (3-NT), AQP1, and Iba-1. No difference in Aqp1 expression was observed in the whole brain; however, it was detected in dTG mice after capillary deprivation. AQP1 immunostaining revealed immunoreaction in blood vessels. After heat exposure, wild-type and dTG mice showed electrolyte abnormalities compared with non-heatstroke wild-type mice. Hepatic damage markers were significantly higher in dTG mice than in wild-type mice. Hematoxylin–eosin staining and 3-NT immunoreactivity in the liver indicated hepatic damage. The number of Iba-1-positive cells adherent to hepatic vasculature was significantly higher in dTG mice than in wild-type mice. This study is the first to suggest that endothelial AQP1 contributes to hepatic damage after heatstroke. [ABSTRACT FROM AUTHOR]

Accumulation of senescent endothelial cells (ECs) with age is a pivotal driver of cardiovascular diseases in aging. However, little is known about the mechanisms and signaling pathways that regulate EC senescence. In this report, we delineate a previously unrecognized role of aquaporin 1 (AQP1) in orchestrating extracellular hydrogen peroxide (H2O2)-induced cellular senescence in aortic ECs. Our findings underscore AQP1's differential impact on senescence hallmarks, including cell-cycle arrest, senescence-associated secretory phenotype (SASP), and DNA damage responses, intricately regulating angiogenesis. In proliferating ECs, AQP1 is crucial for maintaining angiogenic capacity, whereas disruption of AQP1 induces morphological and mitochondrial alterations, culminating in senescence and impaired angiogenesis. Conversely, Aqp1 knockdown or selective blockade of AQP1 in senescent ECs rescues the excess H2O2-induced cellular senescence phenotype and metabolic dysfunction, thereby ameliorating intrinsic angiogenic incompetence. Mechanistically, AQP1 facilitates H2O2 transmembrane transport, exacerbating oxidant-sensitive kinases CaMKII-AMPK. This process suppresses HDAC4 translocation, consequently de-repressing Mef2A-eNOS signaling in proliferating ECs. However, in senescent ECs, AQP1 overexpression is linked to preserved HDAC4-Mef2A complex and downregulation of eNOS signaling. Together, our studies identify AQP1 as a novel epigenetic regulator of HDAC4-Mef2A-dependent EC senescence and angiogenic potential, highlighting its potential as a therapeutic target for antagonizing age-related cardiovascular diseases.

The brain's glymphatic system, a fluid exchange system, is associated with the aquaporin 4 (AQP4) water channels in astrocytes and aquaporin 1 (AQP1) in the ventricular choroid plexus. Circadian rhythms have also been reported to maintain fluid homeostasis in the brain. In this study, we aimed to determine the relationship between melatonin (pinealectomy and exogenous melatonin supplementation), which regulates circadian rhythm, and AQP4 and AQP1. The study, 50 male rats were divided into five groups (n=10). The groups were determined as Control, Sham Pinealectomy (Sham PX), Melatonin (MEL), Pinealectomy (PX), and PX+MEL. The MEL group received intraperitoneal injection of MEL (10 mg/kg/day) for 30 days, and the PX group received only PX surgery. We examined changes in AQP1 and AQP4 expression in brain tissue after PX surgery (MEL deprivation) and MEL injections. While there was no statistically significant difference in AQP1 and AQP4 levels between the control and Sham PX groups, a significant decrease was observed in the PX group (p<0.001). While an increase in AQP4 level was observed in the PX+MEL group (p<0.001), the AQP1 level did not change. This study demonstrated that MEL significantly contributed to the glymphatic system via AQP4 but not AQP1. [ABSTRACT FROM AUTHOR]

Abstract Background The glioblastoma has served as a valuable experimental model system for investigating the growth and invasive properties of glioblastoma. Aquaporin-1 (AQP1) in facilitating cell migration and potentially contributing to tumor progression. In this study, we analyzed the role of AQP1 overexpression in glioblastoma and elucidated the main mechanisms involved. Methods AQP1 overexpression recombinant vector was introduced into C6 rat glioma cells to construct an AQP1 overexpression C6 cell line, and its effect on cell viability and migration ability was detected by MTT and Transwell. RNA was extracted by Trizol method for gene sequencing and transcriptomics analysis, and the differentially expressed genes (DEGs) were enriched for up- and downregulated genes by Principal component analysis (PCA), and the molecular mechanism of AQP1 overexpression was analyzed in comparison with the control group using the NCBI GEO database. Statistical analysis was performed using Mann-Whitney paired two tailed t test. Results The cell viability of AQP1-transfected cell lines increased by 23% and the mean distance traveled increased by 67% compared with the control group. Quantitative analysis of gene expression showed that there were 12,121 genes with an average transcripts per million (TPM) value greater than 1. DEGs accounted for 13% of the genes expressed, with the highest correlation with upregulated genes being FOXO4 and MAZ, and the highest with downregulated genes being E2F TFs. Conclusions AQP1 may be implicated in glioma formation by interacting with the transcriptional regulation networks involving the FOXO4, MAZ, and E2F1/2. These findings shed light on the potential significance of AQP1 in glioma pathogenesis and warrant further investigations to unravel the underlying molecular mechanisms.

Heatstroke induces fluid loss and electrolyte abnormalities owing to high ambient temperature (AT) and relative humidity (RH). Aquaporin 1 (AQP1) is a key protein for water homeostasis; however, its role in heatstroke remains unclear. This study examines endothelial AQP1 in Tie2-Cre/LNL-AQP1 double transgenic (dTG) mice with upregulated Aqp1 in endothelial cells. For experimental heatstroke, mice were exposed to 41 °C AT and >99% RH. Blood, brain, kidney, and liver samples were collected 24 h later. Blood was analyzed for electrolytes and tissue damage markers, and organs were examined using morphological and immunohistological staining for 3-nitrotyrosine (3-NT), AQP1, and Iba-1. No difference in Aqp1 expression was observed in the whole brain; however, it was detected in dTG mice after capillary deprivation. AQP1 immunostaining revealed immunoreaction in blood vessels. After heat exposure, wild-type and dTG mice showed electrolyte abnormalities compared with non-heatstroke wild-type mice. Hepatic damage markers were significantly higher in dTG mice than in wild-type mice. Hematoxylin–eosin staining and 3-NT immunoreactivity in the liver indicated hepatic damage. The number of Iba-1-positive cells adherent to hepatic vasculature was significantly higher in dTG mice than in wild-type mice. This study is the first to suggest that endothelial AQP1 contributes to hepatic damage after heatstroke.

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease affecting approximately 1% of the global population, with a higher prevalence in women than in men. Chronic inflammation and oxidative stress play pivotal roles in the pathogenesis of RA. Anethole, a prominent compound derived from fennel (Foeniculum vulgare), possesses a spectrum of therapeutic properties, including anti‐arthritic, anti‐inflammatory, antioxidant, and tumor‐suppressive effects. However, its specific impact on RA remains underexplored. This study sought to uncover the potential therapeutic value of anethole in treating RA by employing an H2O2‐induced inflammation model with HIG‐82 synovial cells. Our results demonstrated that exposure to H2O2 induced the inflammation and apoptosis in these cells. Remarkably, anethole treatment effectively countered these inflammatory and apoptotic processes triggered by H2O2. Moreover, we identified the aquaporin 1 (AQP1) and protein kinase A (PKA) pathway as critical regulators of inflammation and apoptosis. H2O2 stimulation led to an increase in the AQP1 expression and a decrease in p‐PKA‐C, contributing to cartilage degradation. Conversely, anethole not only downregulated the AQP1 expression but also activated the PKA pathway, effectively suppressing cell inflammation and apoptosis. Furthermore, anethole also inhibited the enzymes responsible for cartilage degradation. In summary, our findings highlight the potential of anethole as a therapeutic agent for mitigating H2O2‐induced inflammation and apoptosis in synovial cells, offering promising prospects for future RA treatments. [ABSTRACT FROM AUTHOR]

Background: The glioblastoma has served as a valuable experimental model system for investigating the growth and invasive properties of glioblastoma. Aquaporin-1 (AQP1) in facilitating cell migration and potentially contributing to tumor progression. In this study, we analyzed the role of AQP1 overexpression in glioblastoma and elucidated the main mechanisms involved. Methods: AQP1 overexpression recombinant vector was introduced into C6 rat glioma cells to construct an AQP1 overexpression C6 cell line, and its effect on cell viability and migration ability was detected by MTT and Transwell. RNA was extracted by Trizol method for gene sequencing and transcriptomics analysis, and the differentially expressed genes (DEGs) were enriched for up- and downregulated genes by Principal component analysis (PCA), and the molecular mechanism of AQP1 overexpression was analyzed in comparison with the control group using the NCBI GEO database. Statistical analysis was performed using Mann-Whitney paired two tailed t test. Results: The cell viability of AQP1-transfected cell lines increased by 23% and the mean distance traveled increased by 67% compared with the control group. Quantitative analysis of gene expression showed that there were 12,121 genes with an average transcripts per million (TPM) value greater than 1. DEGs accounted for 13% of the genes expressed, with the highest correlation with upregulated genes being FOXO4 and MAZ, and the highest with downregulated genes being E2F TFs. Conclusions: AQP1 may be implicated in glioma formation by interacting with the transcriptional regulation networks involving the FOXO4, MAZ, and E2F1/2. These findings shed light on the potential significance of AQP1 in glioma pathogenesis and warrant further investigations to unravel the underlying molecular mechanisms. [ABSTRACT FROM AUTHOR]

Background: Aquaporins (AQPs) are transmembrane channel proteins. Aquaporin 1 (AQP1), Aquaporin 3 (AQP3), and Aquaporin 7 (AQP7) are expressed in the jejunum. The purpose of this study was to ascertain how a high-fat high-fructose diet (HFFD) and intermittent fasting (IF) affect AQP1, AQP3, and AQP7 expression in the rat jejunum. Methods: Sixteen adult male rats were divided into control rats (n = 4) fed on a basal diet and water ad libitum for 12 weeks; IF control rats (n = 4) followed the IF protocol, HFFD-fed rats (n = 8) fed HFFD for eight weeks, and rats were randomized into two groups: HFFD only or HFFD and IF protocol from the beginning of the 9th week until the end of the experiment. The lipid profile values were assessed after 12 weeks. Jejunal oxidative markers (malondialdehyde and reduced glutathione) and AQP1, AQP3, and AQP7 mRNA expression were measured. Jejunal sections were used for morphometric analysis of villus length and crypt depth. Immunohistochemical evaluation of AQP1, AQP3, and AQP7 expression was also performed. Results: IF ameliorates HFFD-induced lipid profile, oxidative stress, and jejunal morphometric changes. The results of both mRNA expression using PCR and immunohistochemistry showed a significant increase in AQP1, AQP3, and AQP7 expression in HFFD, whereas IF caused a decline in this expression. Conclusion: These findings suggest that IF can reduce inflammation, and oxidative stress and restore jejunal morphology caused by HFFD.

Background: Aquaporins (AQPs) are a family of membrane proteins that act as channels for water, facilitating its movement across the plasma membrane of cells. Aquaporin1 (AQP1), located in the choroid plexus, is thought to be involved in the process of cerebrospinal fluid (CSF) production. Objective: The objective of this study is to examine the impact of hydrocephalus and cerebrospinal fluid (CSF) drainage on the expression of AQP1 in a mice model of hydrocephalus. Material and Methods: Laboratory experimental study with six groups. Five test groups, one control group, and a rat model of hydrocephalus caused by kaolin were used in the experiment. Results: Hydrocephalus in mice model induced by kaolin, and CSF drainage was performed on the 7th and 14th days group. Immunohistochemical analysis was conducted to examine the presence of AQP1 in the choroid plexus using microscopes. The findings revealed a noticeable decrease in AQP1 expression levels in the choroid plexus, which exhibited a semi-quantitative decline in correlation with the duration of hydrocephalus (p = 0.01). This decrease was observed when comparing the normal group with the hydrocephalus groups on the 7th, 14th, and 21st days following induction. However, after cerebrospinal fluid (CSF) drainage, there was a significant increase in AQP1 expression (p < 0.05). Conclusions: This study shows the significant role of AQP1 in CSF production by comparing of AQP1 expression in the choroid plexus of hydrocephalus mice model, with and without CSF drainage. AQP1 expression experiences downregulation in hydrocephalus mice model and upregulation after CSF drainage. [ABSTRACT FROM AUTHOR]

This study was designed to investigate the role of aquaporin 1 (AQP1) in ferroptosis, macrophage polarization, mitochondrial dysfunction, and impaired autophagy of lipopolysaccharide (LPS)-stimulated RAW264.7 cells and explored the underlying mechanisms. Si-AQP1-mediated AQP1 silencing RAW264.7 cells was constructed. Si-P53-mediated P53 silencing or pcDNA-P53 overexpression RAW264.7 cells was constructed. Assays of ATP, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Mitochondrial membrane potential (JC-1) staining were performed to evaluate mitochondrial biological function. Assays of flow cytometry, reactive oxygen species (ROS) staining, western blot (WB), RT-qPCR, malondialdehyde (MDA), glutathione (GSH), and total superoxide dismutase (SOD) were performed to detect cell ferroptosis, macrophage polarization, and impaired autophagy. The involvement of the P53 pathway was revealed by WB. The results showed that LPS (30 μg/mL) could induce ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage in RAW264.7 cells. Meanwhile, the expression of AQP1 was increased and the expression of P53 was decreased. In addition, Pifithrin-α (PIF; 15 μM), a P53 inhibitor, significantly aggravated ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage as well as up-regulation of AQP1 protein expression in LPS-induced RAW264.7 cells. Interestingly, this phenomenon was markedly alleviated by Kevetrin hydrochloride (70 μM), a P53 agonist. Mechanistically, silencing AQP1 significantly alleviated ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage by up-regulating the expression of P53 in LPS-stimulated RAW264.7 cells. Indeed, inhibition of P53 expression by PIF treatment dramatically reversed this effect on the basis of LPS+si-AQP1. Therefore, we concluded for the first time that AQP1 can promote ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy impairment by inhibiting the expression of P53 in LPS-stimulated RAW264.7 cells, and AQP1 or P53 may be considered as a crucial determiner that can regulate the biological behavior of RAW264.7 cells stimulated by LPS. [ABSTRACT FROM AUTHOR]

Recently, some studies have suggested a link between AQP1 and cancer progression. The aim of the present study was to investigate the influence of AQP1 on the clinicopathology and prognosis of intrahepatic cholangiocarcinoma (ICC) patients. We retrospectively detected the expression of AQP1 protein in 307 patients with ICC who underwent partial hepatectomy. Western blot analysis was used to detect AQP1 protein levels in stable AQP1 overexpression and knockdown cell lines. The influence of AQP1 on the invasion and metastasis ability of ICC cells was assessed by wound-healing and Transwell assays in vitro as well as by a splenic liver metastasis model in vivo. Positive membranous AQP1 expression was identified in 34.2% (105/307) of the ICC specimens. Survival data revealed that positive AQP1 expression was significantly associated with favourable disease-free survival (DFS) and overall survival (OS) (p = 0.0290 and p = 0003, respectively). Moreover, high AQP1 expression inhibited the invasion and migration of ICC cells in vitro as well as inhibited liver metastasis in nude mice. Mechanistically, high AQP1 expression in ICC cells increased the levels of E-cadherin but decreased the levels of the Snail transcription factor. AQP1 expression is associated with a favourable prognosis in ICC patients. AQP1 inhibits ICC cell invasion, metastasis, and epithelial-mesenchymal transition (EMT) through downregulation of Snail expression. [ABSTRACT FROM AUTHOR]

Renal interstitial fibrosis (RIF) is the crucial pathway in chronic kidney disease (CKD) leading to the end-stage renal failure. However, the underlying mechanism of Shen Qi Wan (SQW) on RIF is not fully understood. In the current study, we investigated the role of Aquaporin 1 (AQP1) in SQW on tubular epithelial-to-mesenchymal transition (EMT). A RIF mouse model induced by adenine and a TGF- β 1-stimulated HK-2 cell model were etablished to explore the involvement of AQP 1 in the protective effect of SQW on EMT in vitro and in vivo. Subsequently, the molecular mechanism of SQW on EMT was explored in HK-2 cells with AQP1 knockdown. The results indicated that SQW alleviated kidney injury and renal collagen deposition in the kidneys of mice induced by adenine, increased the protein expression of E-cadherin and AQP1 expression, and decreased the expression of vimentin and α -smooth muscle actin (α -SMA). Similarly, treatmement with SQW-containing serum significantly halted EMT process in TGF- β 1 stimulated HK-2 cells. The expression of snail and slug was significantly upregulated in HK-2 cells after knockdown of AQP1. AQP1 knockdown also increased the mRNA expression of vimentin and α -SMA, and decreased the expression of E-cadherin. The protein expression of vimentin increased, while the expression of E-cadherin and CK-18 significantly decreased after AQP1 knockdown in HK-2 cells. These results revealed that AQP1 knockdown promoted EMT. Furthermore, AQP1 knockdown abolished the protective effect of SQW-containing serum on EMT in HK-2 cells. In sum, SQW attentuates EMT process in RIF through upregulation of the expression of AQP1. [ABSTRACT FROM AUTHOR]

Glucose is widely used as an osmotic agent in fluids for peritoneal dialysis. The aim of this work was to study the effect of glucose on the expression of the aquaporin-1 (AQP1) water channel and TonEBP transcription factor, as well as on plasma membrane water permeability of cells in the primary culture of Wistar rat mesenteric mesotheliocytes, using fluorescence microscopy with the intracellular fluorescent dye сalcein. mRNA contents were assessed by real time RT-PCR. Preincubation of cells in a DMEM medium containing glucose (2.3%, 24 h, 37°C, 5% CO2) led to a decrease in the expression of the aqp1 gene by about 60% (control 0.87 ± 0.18; glucose 0.34 ± 0.12, n = 9, p < 0.05) and the tonebp gene by 20% (control 0.37 ± 0.024; glucose 0.3 ± 0.012, n = 9, p < 0.05). A 40% decrease in plasma membrane water permeability of peritoneal mesotheliocytes was also observed after 24-h preincubation with glucose (control 7.3E-3 ± 1.3E-3 (cm/s), n = 27; glucose 4.3E-3 ± 3.8E-4 (cm/s), n = 57, p < 0.01). These results indicate that glucose can exert an inhibitory effect on transport processes in peritoneal mesothelial cells, which, under multiple exposures, may result in structural and functional disorders of the peritoneal membrane. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aquaporins (AQPs) are water channels in the cell membrane that regulate osmosis in response to rapid changes in intracellular and extracellular fluid concentration caused by extrinsic factors. While there are so many studies on the association of AQPs with muscular atrophy, sarcopenia, and Duchenne muscular dystrophy (DMD), the expression of AQP has not been verified in naturally aging mice or humans. Notably, due to the characteristics of AQPs, the difference in function cannot be evaluated without extrinsic factors such as acute water restriction. The purpose of this study was to investigate the changes in AQPs expression and function due to natural aging under acute water restriction conditions in aging mice. The expression of AQP4 was shown to decrease with aging similar to previous studies. However, for the first time, this study results confirmed that AQP1 expression increased in aging mice. In addition, the expression of Aqp1 decreased in the acute water restricted group compared to the control group after acute water restriction in aging mice. These results suggest that although the expression of AQP1 increases with aging, its function is reduced. We also confirmed that overexpression of Aqp1 can inhibit myotube differentiation and that knockdown can promote myotube differentiation through in vitro experiments. In conclusion, based on our results, we suggest that the AQP1 is an important factor in sarcopenia caused by natural aging accompanied by chronic dehydration. [ABSTRACT FROM AUTHOR]

In response to collagen stimulation, platelets use a coordinated system of fluid entry to undergo membrane ballooning, procoagulant spreading, and microvesiculation. We hypothesized that water entry was mediated by the water channel aquaporin-1 (AQP1) and aimed to determine its role in the platelet procoagulant response and thrombosis. We established that human and mouse platelets express AQP1 and localize to internal tubular membrane structures. However, deletion of AQP1 had minimal effects on collagen-induced platelet granule secretion, aggregation, or membrane ballooning. Conversely, procoagulant spreading, microvesiculation, phosphatidylserine exposure, and clot formation time were significantly diminished. Furthermore, in vivo thrombus formation after FeCl3 injury to carotid arteries was also markedly suppressed in AQP1-null mice, but hemostasis after tail bleeding remained normal. The mechanism involves an AQP1-mediated rapid membrane stretching during procoagulant spreading but not ballooning, leading to calcium entry through mechanosensitive cation channels and a full procoagulant response. We conclude that AQP1 is a major regulator of the platelet procoagulant response, able to modulate coagulation after injury or pathologic stimuli without affecting other platelet functional responses or normal hemostasis. Clinically effective AQP1 inhibitors may therefore represent a novel class of antiprocoagulant antithrombotics.

Pulmonary arterial hypertension (PAH) is a rare disorder with a poor prognosis. Deleterious variation within components of the transforming growth factor-β pathway, particularly the bone morphogenetic protein type 2 receptor (BMPR2), underlies most heritable forms of PAH. To identify the missing heritability we perform whole-genome sequencing in 1038 PAH index cases and 6385 PAH-negative control subjects. Case-control analyses reveal significant overrepresentation of rare variants in ATP13A3, AQP1 and SOX17, and provide independent validation of a critical role for GDF2 in PAH. We demonstrate familial segregation of mutations in SOX17 and AQP1 with PAH. Mutations in GDF2, encoding a BMPR2 ligand, lead to reduced secretion from transfected cells. In addition, we identify pathogenic mutations in the majority of previously reported PAH genes, and provide evidence for further putative genes. Taken together these findings contribute new insights into the molecular basis of PAH and indicate unexplored pathways for therapeutic intervention.

Metabolic stress-induced pancreatic β cell senescence plays a pivotal role in the type 2 diabetes progression, and yet the precise molecular mechanisms remain elusive. Through cellular experiments and bioinformatics analyses, we identified aquaporin 1(AQP1)-mediated transmembrane transport of hydrogen peroxide as a key driver of glucolipotoxicity-induced senescence in MIN6 cells. A PPI network analysis was used to cross-reference 17 differentially expressed genes associated with type 2 diabetes from three independent GEO databases with 188 stress-induced senescence-related genes from CellAge. AQP1 was revealed as a critical molecular nexus connecting diabetes, oxidative stress, and cellular senescence. AQP1 inhibition, through Bacopaside II and si-AQP1, significantly reduced critical senescence markers in MIN6 cells, demonstrated by the reversal of glucolipotoxicity-induced upregulation of p16, p21, and p-γH2A.X, activation of the senescence-associated secretory phenotype genes, and an elevated percentage of senescence-associated-β-galactosidase positive cells. These effects were primarily mediated through oxidative stress MAPK signaling pathway modulation. AQP1 inhibition is crucial in alleviating glucolipotoxicity-induced β cell senescence. It underscores its potential as a molecular target for therapeutic strategies to delay pancreatic β cell senescence by modulating antioxidant pathways during metabolic stress., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This study aims to investigate the effects of astragalus polysaccharide (APS) on diabetic retinopathy through the SHH-Gli1-AQP1 pathway. The anti-type 2 diabetes mellitus (T2DM) targets of APS were identified through comprehensive searches of drug and disease-related databases. A protein-protein interaction network was then constructed, followed by GO and KEGG enrichment analyses. Molecular docking simulations were performed to evaluate the interactions of APS and metformin with Gli1 and AQP1. An in vivo T2DM rat model was established via streptozotocin (STZ) injection and treated with metformin and varying doses of APS for 12 weeks. Histological changes in retinal cells were assessed using H&E and PAS staining. The expression levels of AQP1, Gli1, and SHH in the retina were measured using immunohistochemistry, Western blotting, immunofluorescence, and ELISA. Additionally, mRNA expression of AQP1, Gli1, and SHH was quantified by RT-qPCR. Bioinformatic analyses indicated that Gli1 and AQP1, key components of the SHH-Gli1- AQP1 signaling pathway, may be associated with T2DM. Subsequent experiments demonstrated that the STZ-induced T2DM rats exhibited significant retinal damage, which was notably mitigated by both APS and metformin treatments. Furthermore, the SHH-Gli1-AQP1 signaling pathway was found to be overactivated in STZ-induced T2DM rats. Treatment with APS and metformin significantly reduced the elevated expression levels of SHH, Gli1, and AQP1. APS effectively inhibits retinal damage of STZ-induced T2DM rats by restraining the SHH-Gli1-AQP1 signaling pathway.

Accumulation of senescent endothelial cells (ECs) with age is a pivotal driver of cardiovascular diseases in aging. However, little is known about the mechanisms and signaling pathways that regulate EC senescence. In this report, we delineate a previously unrecognized role of aquaporin 1 (AQP1) in orchestrating extracellular hydrogen peroxide (H 2 O 2 )-induced cellular senescence in aortic ECs. Our findings underscore AQP1's differential impact on senescence hallmarks, including cell-cycle arrest, senescence-associated secretory phenotype (SASP), and DNA damage responses, intricately regulating angiogenesis. In proliferating ECs, AQP1 is crucial for maintaining angiogenic capacity, whereas disruption of AQP1 induces morphological and mitochondrial alterations, culminating in senescence and impaired angiogenesis. Conversely, Aqp1 knockdown or selective blockade of AQP1 in senescent ECs rescues the excess H 2 O 2 -induced cellular senescence phenotype and metabolic dysfunction, thereby ameliorating intrinsic angiogenic incompetence. Mechanistically, AQP1 facilitates H 2 O 2 transmembrane transport, exacerbating oxidant-sensitive kinases CaMKII-AMPK. This process suppresses HDAC4 translocation, consequently de-repressing Mef2A-eNOS signaling in proliferating ECs. However, in senescent ECs, AQP1 overexpression is linked to preserved HDAC4-Mef2A complex and downregulation of eNOS signaling. Together, our studies identify AQP1 as a novel epigenetic regulator of HDAC4-Mef2A-dependent EC senescence and angiogenic potential, highlighting its potential as a therapeutic target for antagonizing age-related cardiovascular diseases., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Soheil Saeedi reports was provided by University of Zurich. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The aim of this study was to identify potential plasma biomarkers for hepatitis B virus (HBV)‐related liver diseases. High‐throughput transcriptome sequencing analysis was performed on five patients with chronic hepatitis B (CHB), five patients with HBV‐associated liver fibrosis/liver cirrhosis (LF/LC), and four healthy participants. By short time‐series expression miner and functional analysis, aquaporin 1 (AQP1), dystroglycan 1 (DAG1), and hemoglobin subunit beta (HBB) were identified as potential biomarkers. Immunohistochemical analysis revealed that the expression levels of AQP1, DAG1, and HBB were upregulated in the three groups. Subsequent enzyme‐linked immunosorbent assay tests on the training cohort (n = 150) indicated that the plasma levels of AQP1 and DAG1 were highest in LF/LC patients, followed by those in CHB patients, and the lowest in healthy controls. APAD model, a diagnostic panel incorporating age, platelet, AQP1, and DAG1 levels, exhibited the strongest stratification ability to distinguish LF/LC patients from CHB patients, and to differentiate CHB patients from healthy controls. Furthermore, the diagnostic accuracies of the biomarkers and APAD model were verified in an independent cohort consisting of 230 participants. In conclusion, both AQP1 and DAG1 have good diagnostic values and APAD model greatly enhances the diagnostic accuracy for HBV‐related hepatic diseases. [ABSTRACT FROM AUTHOR]

Purpose: To specifically diagnose malignant tumors in DWI using the human telomerase reverse transcriptase (hTERT) promoter–driven AQP1 expression. Methods: The human telomerase reverse transcriptase (hTERT) promoter–driven AQP1 gene overexpression lentivirus system (hTERT-AQP1) and cytomegalovirus (CMV) promoter–driven AQP1 gene overexpression lentivirus system (CMV-AQP1) were prepared, and transduced into telomerase-positive and -negative cells. The AQP1 expression and DWI signal intensity (SI) change in transduced cells were analyzed. Balb/C nude mice subcutaneous xenograft models derived from lentivirus-transduced telomerase-positive and -negative cells were used to evaluate AQP1 expression and DWI SI change in vivo. We further established another group of subcutaneous xenograft model using pristine telomerase-positive and -negative cells, followed by injecting the lentiviral vectors intratumorally or intravenously, to determine the malignant tumor-targeted imaging of hTERT-AQP1. Results: The hTERT-AQP1 and CMV-AQP1 were successfully prepared. After transduction, hTERT-AQP1 could induce the specific overexpression of AQP1 in telomerase-positive cells. Compared with untransduced cells, all CMV-AQP1-pretransduced cells and hTERT-AQP1-pretransduced telomerase-positive cells showed decreased SI and increased apparent diffusion coefficient (ADC) in DWI, while hTERT-AQP1-pretransduced telomerase-negative cells showed no obvious SI and ADC change. Correspondingly, hTERT-AQP1-transduced telomerase-positive tumors and CMV-AQP1-transduced telomerase-positive and -negative tumors showed decreased DWI SI and increased ADC, while hTERT-AQP1-transduced telomerase-negative tumor had no SI and ADC changes. After intratumoral or intravenous injection, CMV-AQP1 could upregulate AQP1 expression and induce DWI SI and ADC alteration in both telomerase-positive and -negative tumors, while hTERT-AQP1 worked in telomerase-positive tumors specifically. Conclusion: Cancers can be specifically visualized based on the DWI signal alteration which triggered by hTERT-AQP1 lentivirus system that combined AQP1 gene and hTERT promoter. [ABSTRACT FROM AUTHOR]

Meng-yuan Zhou,1,* Li Cai,1,2,* Xiao-wen Feng,1 Yu-rong Mu,1 Bo Meng,1 Fang-yuan Liu,1 Rong Li1 1Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, School of Pharmacy, Anhui Medical University, Hefei, 230032, Anhui Province, People’s Republic of China; 2Department of Pathology, School of Basic Medicine, Anhui Medical University, Hefei, 230032, Anhui Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Rong LiSchool of Pharmacy, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui Province, People’s Republic of ChinaTel +86 551-65172132Email aydlirong@163.comIntroduction: Previous studies have confirmed the pathologic role of synovial aquaporin 1 (AQP1) in rheumatoid arthritis (RA), but its associations with the abnormal biologic behaviors of fibroblast-like synoviocytes (FLS) remain unclear. Herein, we examined the roles of AQP1 in the proliferation, migration and invasion of TNF-α-stimulated RA FLS (MH7A cells) and explored the underlying mechanisms.Materials and Methods: Lentivirus-mediated AQP1 overexpression or silencing MH7A cells was constructed. Assays of MTT, flow cytometry (PI staining and Annexin V-PE/7-AAD staining), TMRM staining, wound-healing, transwell and phalloidin staining were performed to detect cell proliferation, cycle distribution, apoptosis, migration and invasion. The involvement of Wnt/β-catenin pathway was revealed by Western blot and β-catenin immunofluorescence staining.Results: AQP1 overexpression promoted cell proliferation of TNF-α-stimulated MH7A by facilitating transformation from G0/G1 to S phase and inhibiting cell apoptosis (ie, reduced apoptosis rates, raised mitochondrial membrane potential, increased Bcl-2 protein level and decreased levels of Bax and cleaved caspase 3 protein). Also, AQP1 overexpression increased the migration index as well as the numbers of migrated and invasive cells. Furthermore, AQP1 overexpression promoted the activation of Wnt/β-catenin pathway, and XAV939, an inhibitor of Wnt/β-catenin, canceled the above effects of AQP1 overexpression on MH7A cells. As expected, AQP1 silencing exhibited the opposite effects on TNF-α-stimulated MH7A cells, which could be reversed by LiCl, an activator of Wnt/β-catenin.Conclusion: AQP1 can affect the proliferation, migration and invasion of MH7A cells by Wnt/β-catenin signaling pathway, and AQP1 can be as a crucial determiner that can regulate RA FLS biologic behaviors.Keywords: aquaporin 1, rheumatoid arthritis, fibroblast-like synoviocytes, Wnt/β-catenin signaling pathway, biologic behaviors

Abstract Background Vascular endothelial cells (ECs) are subject to continuous shear stress due to blood circulation. Mechanical stress due to high shear flow can also cause arteriovenous malformation (AVM) when ECs respond hyper-sensitively to shear flow. This study was conducted to test the hypothesis that angiogenesis could be promoted in response to mechanical stress via regulation of pro-angiogenic factors in AVM cells. Methods ECs were extracted from the tissue samples from six AVM patients and six normal patients. Shear stress at 7 dynes/cm2 were applied for 24 h. Before and after application of shear stress to each group, RT-PCR was performed to access the expression levels of angiopoietin2(AGP2), aquaporin1(AQP1) and TGFβR1. Immunofluorescences was also performed to evaluate the level of protein expressions. Results In both normal and AVM tissues, AGP2 and TGFβR1 under the shear stress showed increased expression in the ECs compared to the non-sheared samples. When AVMs and normal arterial vasculature were compared, the expression levels of both AGP2 and TGFβR1 in AVMs were higher when compared to normal arterial vasculature with or without shear stress. Immunofluorescence-based protein analysis also confirmed shear-induced AGP2 and TGFβR1 in both samples of normal and AVM patients. Conclusions AVMs exhibited higher sensitivity to shear stress by producing higher expressions of some marked genes and proteins that regulate the endothelial functions upon exposure to shear stress. While the physiological mechanism for AVMs remain elusive, our study shows the plausibility of physical stress imposed by the shearing flow can cause the occurrence of AVMs.

Human norovirus (HuNoV) is one of the major pathogens of acute nonbacterial gastroenteritis. Due to the lack of a robust and reproducible in vitro culture system and an appropriate animal model, the mechanism underlying HuNoV-caused diarrhea remains unknown. In the current study, we found that HuNoV transfection induced the expression of aquaporin 1 (AQP1), which was further confirmed in the context of virus infection, whereas the enterovirus EV71 (enterovirus 71) did not have such an effect. We further revealed that VP1, the major capsid protein of HuNoV, was crucial in promoting AQP1 expression. Mechanistically, HuNoV induces AQP1 production through the NF-κB signaling pathway via inducing the expression, phosphorylation and nuclear translocation of p65. By using a model of human intestinal epithelial barrier (IEB), we demonstrated that HuNoV and VP1-mediated enhancement of small molecule permeability is associated with the AQP1 channel. Collectively, we revealed that HuNoV induced the production of AQP1 by activating the NF-κB signaling pathway. The findings in this study provide a basis for further understanding the significance of HuNoV-induced AQP1 expression and the potential mechanism underlying HuNoV-caused diarrhea. [ABSTRACT FROM AUTHOR]

The aquaporin-1 (AQP1) water channel is a potentially important drug target, as AQP1 inhibition is predicted to have therapeutic action in edema, tumor growth, glaucoma, and other conditions. Here, we measured the AQP1 inhibition efficacy of 12 putative small-molecule AQP1 inhibitors reported in six recent studies, and one AQP1 activator. Osmotic water permeability was measured by stopped-flow light scattering in human and rat erythrocytes that natively express AQP1, in hemoglobin-free membrane vesicles from rat and human erythrocytes, and in plasma membrane vesicles isolated from AQP1-transfected Chinese hamster ovary cell cultures. As a positive control, 0.3 mM HgCl2 inhibited AQP1 water permeability by >95%. We found that none of the tested compounds at 50 µM significantly inhibited or increased AQP1 water permeability in these assays. Identification of AQP1 inhibitors remains an important priority.

Yu-rong Mu1,2 ,* Meng-yuan Zhou1,2 ,* Li Cai,3 Ming-ming Liu,1,2 Rong Li1,2 1School of Pharmacy, Anhui Medical University, Hefei, Anhui Province, People’s Republic of China; 2Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, People’s Republic of China; 3Department of Pathology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Rong LiSchool of Pharmacy, Anhui Medical University, Hefei, Anhui Province, People’s Republic of ChinaEmail aydlirong@163.comIntroduction: Previous studies have confirmed that aquaporin 1 (AQP1) is up-regulated in synovium of rheumatoid arthritis (RA), but its exact pathogenic mechanisms in RA are unclear. This study revealed the pathogenic role of AQP1 in rat collagen-induced arthritis (CIA) and the underlying mechanisms related to β-catenin signaling.Materials and Methods: Secondary paw swelling and pathological changes of ankle joints were used to evaluate the severity of rat CIA. Synovial AQP1 and β-catenin expression were measured by immunohistochemistry (IHC) and Western blot assay. AQP1 siRNA was applied to knockdown AQP1 in cultured CIA fibroblast-like synoviocyte (FLS). Assays of MTT, PCNA immunofluorescence and transwell were performed to detect cell proliferation, migration and invasion. The protein levels of β-catenin pathway members and ratio of TOP/FOP luciferase activity were also measured.Results: In vivo, we revealed that synovial AQP1 and β-catenin expressions in CIA rats were higher than normal rats, and synovial AQP1 expression of CIA rats increased in parallel with secondary paw swelling and total pathological score on joint damage. Correlation analysis of IHC results indicated that synovial AQP1 expression positively correlated with β-catenin expression in CIA rat. In vitro, AQP1 siRNA apparently reduced the proliferation, migration and invasion of CIA FLS by inhibiting β-catenin signaling pathway. As an activator of β-catenin signaling, lithium chloride (an inhibitor of GSK-3β) reversed the inhibitory effects of AQP1 siRNA on the cultured CIA FLS.Conclusion: We concluded that the overexpression of synovial AQP1 aggravated rat CIA by promoting the activation of FLS through β-catenin signaling pathway.Keywords: aquaporin 1, collagen-induced arthritis, fibroblast-like synoviocyte, rheumatoid arthritis, β-catenin signaling

Abstract Background The classical view of cerebrospinal fluid (CSF) production posits the choroid plexus as its major source. Although previous studies indicate that part of CSF production occurs in the subarachnoid space (SAS), the mechanisms underlying extra-choroidal CSF production remain elusive. We here investigated the distributions of aquaporin 1 (AQP1) and Na+/K+/2Cl− cotransporter 1 (NKCC1), key proteins for choroidal CSF production, in the adult rodent brain and spinal cord. Methods We have accessed AQP1 distribution in the intact brain using uDISCO tissue clearing technique and by Western blot. AQP1 and NKCC1 cellular localization were accessed by immunohistochemistry in brain and spinal cord obtained from adult rodents. Imaging was performed using light-sheet, confocal and bright field light microscopy. Results We determined that AQP1 is widely distributed in the leptomeningeal vasculature of the intact brain and that its glycosylated isoform is the most prominent in different brain regions. Moreover, AQP1 and NKCC1 show specific distributions in the smooth muscle cell layer of penetrating arterioles and veins in the brain and spinal cord, and in the endothelia of capillaries and venules, restricted to the SAS vasculature. Conclusions Our results shed light on the molecular framework that may underlie extra-choroidal CSF production and we propose that AQP1 and NKCC1 within the leptomeningeal vasculature, specifically at the capillary level, are poised to play a role in CSF production throughout the central nervous system.

Sepsis associated Acute kidney injury (AKI) is a common clinical syndrome characterized by suddenly decreased in renal function and urinary volume. This study was designed to investigate the role of Aquaporin 1 (AQP1) and P53 in the development of sepsis-induced AKI and their potential regulatory mechanisms. Firstly, transcriptome sequencing analysis of mice kidney showed AQP1 expression was reduced and P53 expression was elevated in Cecal ligation and puncture (CLP)-induced AKI compared with controls. Bioinformatics confirmed that AQP1 expression was remarkably decreased and P53 expression was obviously elevated in renal tissues or peripheral blood of septic AKI patients. Moreover, we found in vivo experiments that AQP1 mRNA levels were dramatically decreased and P53 mRNA significantly increased following the increased expression of inflammation, apoptosis, fibrosis, NGAL and KIM-1 at various periods in septic AKI. Meanwhile, AQP1 and P53 protein levels increased significantly first and then decreased gradually in kidney tissue and serum of rats in different stages of septic AKI. Most importantly, in vivo and vitro experiments demonstrated that silencing of AQP1 greatly exacerbates renal or cellular injury by up-regulating P53 expression promoting inflammatory response, apoptosis and fibrosis. Overexpression of AQP1 prevented the elevation of inflammation, apoptosis and fibrosis by down-regulating P53 expression in Lipopolysaccharide (LPS)-induced AKI or HK-2 cells. Therefore, our results suggested that AQP1 plays a protective role in modulating AKI and can attenuate inflammatory response, apoptosis and fibrosis via downregulating P53 in septic AKI or LPS-induced HK-2cells. The pharmacological targeting of AQP1 mediated P53 expression might be identified as potential targets for the early treatment of septic AKI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lv, Liao, Li, Liu, Luo, Diao, Wang and Jin.)

Introduction: Acute kidney injury (AKI) is a serious pathology that progress with dysfunction of regulating blood pressure and fluid balance, concentrating urine due to decrement of aquaporin-1 (AQP) levels during the inflammation process. Irbesartan (IRN), angiotensin receptor blocker, is widely used in the treatment of hypertension, which also has anti-inflammatory, antioxidant and anti-apoptotic properties. The aim of this study is to investigate the protective effects of IRN in lipopolysaccharide (LPS)-induced kidney injury., Material and Methods: Twenty-four rats divided into three groups as control, LPS and LPS+IRN group. After 6h of LPS administration, rats were sacrificed. Blood samples and half of the kidney tissues were collected for biochemical analysis and remaining tissues were taken for histopathological and immunohistochemical analysis., Results: In the LPS group, glomerular congestion and shrinkage, degeneration of distal tubules, mononuclear cell infiltration, cellular debris and intense proteinous accumulation in the tubules, increased expressions of Cas-3, nuclear factor kappa beta-p65 (NF-kB p65), levels of creatinin, TOS, OSI and decreased levels of TAS, AQP-1 were found significantly. IRN treatment reversed all these parameters. IRN's restorated AQP-1 levels by its anti-inflammatory, antioxidant and anti-apoptotic effects due to inhibiting NF-kB expression., Conclusion: This study suggests that IRN can be used in conditions affecting the kidneys such as AKI. Further studies needed for detailed molecular investigation of IRN at different doses and durations., (Copyright © 2023 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)

Assessment of the vitality of an injury is one of to the main tasks in daily forensic casework. Aquaporins belong to the family of water channels. They enable the transport of water and of small molecules like glycerol through biological channels. So far, 13 classes of aquaporins are identified in vertebrates. The classical aquaporin channels 1, 2 and 4 are only permeable for water. The aquaporin channels 3, 7, 9 and 10 are also called aquaglycerolporins since they can also transport glycerol. Aquaporin 3 is expressed in epidermal keratinocytes. In the present investigation, the aquaporin 1 and 3 expression in mechanically and thermally damaged skin is investigated by immunohistochemistry. The study collective comprises 30 cases (63.3% male and 36.7% female) with an age range between 19 and 95 years (mean value 54.6 years). The skin injury comprises different kinds of blunt force, sharp force, strangulation marks, thermal injury, gunshot wounds and frost erythema. In all kinds of mechanical and trauma injury, an increased expression of aquaporin 3 in the keratinocytes of the epidermis was found. There is no correlation of the aquaporin 3 expression with age, sex, body mass index, duration of agonal period and postmortem interval. Concerning aquaporin 1, there were no differences between injured and uninjured skin. Aquaporin 3 is independently from the kind of skin injury and appears to be a valuable immunohistochemical parameter of vitality. [ABSTRACT FROM AUTHOR]

Dorsal root ganglion (DRG) neurons transduce peripheral pain signals through small-diameter, non-myelinated C-fibers, which, when injured, can regenerate to restore pain sensation. Water channel aquaporin-1 (AQP1) is expressed at the plasma membrane of cell bodies and axons of DRG neurons, where it modulates the sensing of certain types of pain. Here, we found that AQP1 is also involved in DRG axonal growth and regeneration by a mechanism that may involve water transport-facilitated extension of axonal outgrowths. Spontaneous and nerve growth factor-stimulated axonal extension was reduced in cultures of AQP1-deficient DRG neurons and DRG explants compared to the wildtype. Axonal growth in AQP1-deficient DRG cultures was rescued by transfection with AQP1 or a different water-transporting AQP (AQP4), but not by a non-water-transporting AQP1 mutant. Following sciatic nerve compression injury AQP1 expression was increased in DRG neurons in wildtype mice, and DRG axonal growth was impaired in AQP1-deficient mice. Our results indicate AQP1 as a novel determinant of DRG axonal regeneration and hence a potential therapeutic target to accelerate neuronal regeneration.

Abstract Background Gold nanoparticles (Au-NPs) have extensive applications in electronics and biomedicine, resulting in increased exposure and prompting safety concerns for human health. After absorption, nanoparticles enter circulation and effect endothelial cells. We previously showed that exposure to Au-NPs (40–50 nm) collapsed endothelial tight junctions and increased their paracellular permeability. Inhaled nanoparticles have gained significant attention due to their biodistribution in the brain; however, little is known regarding their role in cerebral edema. The present study investigated the expression of aquaporin 1 (AQP1) in the cerebral endothelial cell line, bEnd.3, stimulated by Au-NPs. Results We found that treatment with Au-NPs induced AQP1 expression and increased endothelial permeability to water. Au-NP exposure rapidly boosted the phosphorylation levels of focal adhesion kinase (FAK) and AKT, increased the accumulation of caveolin 1 (Cav1), and reduced the activity of extracellular regulated protein kinases (ERK). The inhibition of AKT (GDC-0068) or FAK (PF-573228) not only rescued ERK activity but also prevented AQP1 induction, whereas Au-NP-mediated Cav1 accumulation remained unaltered. Neither these signaling molecules nor AQP1 expression responded to Au-NPs while Cav1 was silenced. Inhibition of ERK activity (U0126) remarkably enhanced Cav1 and AQP1 expression in bEnd.3 cells. These data demonstrate that Au-NP-mediated AQP1 induction is Cav1 dependent, but requires the repression on ERK activity. Mice receiving intranasally administered Au-NPs displayed cerebral edema, significantly augmented AQP1 protein levels; furthermore, mild focal lesions were observed in the cerebral parenchyma. Conclusions These data suggest that the subacute exposure of nanoparticles might induce cerebral edema, involving the Cav1 dependent accumulation on endothelial AQP1.

Abstract Background Aquaporins (AQPs) are a family of integral membrane channel proteins that facilitate the transport of water and other small solutes across cell membranes. AQPs appear to play crucial roles in parasite survival and represent possible drug targets for novel intervention strategy. In this work, we investigated the tissue distribution and biological roles of an aquaporin TcAQP1 in the neglected parasitic nematode Toxocara canis. Methods Recombinant C-terminal hydrophilic domain of AQP1 of T. canis (rTcAQP1c) and polyclonal antibody against rTcAQP1c were produced to analyse the tissue expression of native TcAQP1 in adult (female and male) worms using an immunohistochemical approach. RNA interference (RNAi), quantitative real-time PCR (qRT-PCR) and nematocidal assays were performed to investigate the functional roles of TcAQP1 in the adult stage of T. canis. Results Immunofluorescence analysis showed that TcAQP1 was localised predominantly in the epithelial linings of the reproductive tract and basolateral membrane of the intestine in the adult stage (female and male) of T. canis, indicating important roles in reproduction, nutrient absorption and/or osmoregulation. Treatment with silencing RNA for 24 h resulted in a significant reduction of Tc-aqp-1 mRNA level in adult T. canis, though no phenotypical change was observed. The efficient gene knockdown compromised the nematocidal activity of albendazole in vitro, suggesting the role of TcAQP1 in drug uptake. Conclusions The findings of this study provide important information about tissue expression and functional roles of TcAQP1 protein in adult T. canis. Understanding the biological functions of this protein in other developmental stages of T. canis and related parasitic nematodes would contribute to the discovery of novel diagnostic or anthelmintic targets.

Background: Vascular endothelial cells (ECs) are subject to continuous shear stress due to blood circulation. Mechanical stress due to high shear flow can also cause arteriovenous malformation (AVM) when ECs respond hyper-sensitively to shear flow. This study was conducted to test the hypothesis that angiogenesis could be promoted in response to mechanical stress via regulation of pro-angiogenic factors in AVM cells. Methods: ECs were extracted from the tissue samples from six AVM patients and six normal patients. Shear stress at 7 dynes/cm2 were applied for 24 h. Before and after application of shear stress to each group, RT-PCR was performed to access the expression levels of angiopoietin2(AGP2), aquaporin1(AQP1) and TGFβR1. Immunofluorescences was also performed to evaluate the level of protein expressions. Results: In both normal and AVM tissues, AGP2 and TGFβR1 under the shear stress showed increased expression in the ECs compared to the non-sheared samples. When AVMs and normal arterial vasculature were compared, the expression levels of both AGP2 and TGFβR1 in AVMs were higher when compared to normal arterial vasculature with or without shear stress. Immunofluorescence-based protein analysis also confirmed shear-induced AGP2 and TGFβR1 in both samples of normal and AVM patients. Conclusions: AVMs exhibited higher sensitivity to shear stress by producing higher expressions of some marked genes and proteins that regulate the endothelial functions upon exposure to shear stress. While the physiological mechanism for AVMs remain elusive, our study shows the plausibility of physical stress imposed by the shearing flow can cause the occurrence of AVMs. [ABSTRACT FROM AUTHOR]

The water channel aquaporin 1 (AQP1) has been implicated in tumor progression and metastasis. It is hypothesized that AQP1 expression can facilitate the transmembrane water transport leading to changes in cell structure that promote migration. Its impact in neuroblastoma has not been addressed so far. The objectives of this study have been to determine whether AQP1 expression in neuroblastoma is dependent on hypoxia, to demonstrate whether AQP1 is functionally relevant for migration, and to further define AQP1-dependent properties of the migrating cells. This was determined by investigating the reaction of neuroblastoma cell lines, particularly SH-SY5Y, Kelly, SH-EP Tet-21/N and SK-N-BE(2)-M17 to hypoxia, quantitating the AQP1-related water permeability by stopped-flow spectroscopy, and studying the migration-related properties of the cells in a modified transwell assay. We find that AQP1 expression in neuroblastoma cells is up-regulated by hypoxic conditions, and that increased AQP1 expression enabled the cells to form a phenotype which is associated with migratory properties and increased cell agility. This suggests that the hypoxic tumor microenvironment is the trigger for some tumor cells to transition to a migratory phenotype. We demonstrate that migrating tumor cell express elevated AQP1 levels and a hypoxic biochemical phenotype. Our experiments strongly suggest that elevated AQP1 might be a key driver in transitioning stable tumor cells to migrating tumor cells in a hypoxic microenvironment.

Human norovirus (HuNoV) is one of the major pathogens of acute nonbacterial gastroenteritis. Due to the lack of a robust and reproducible in vitro culture system and an appropriate animal model, the mechanism underlying HuNoV-caused diarrhea remains unknown. In the current study, we found that HuNoV transfection induced the expression of aquaporin 1 (AQP1), which was further confirmed in the context of virus infection, whereas the enterovirus EV71 (enterovirus 71) did not have such an effect. We further revealed that VP1, the major capsid protein of HuNoV, was crucial in promoting AQP1 expression. Mechanistically, HuNoV induces AQP1 production through the NF-κB signaling pathway via inducing the expression, phosphorylation and nuclear translocation of p65. By using a model of human intestinal epithelial barrier (IEB), we demonstrated that HuNoV and VP1-mediated enhancement of small molecule permeability is associated with the AQP1 channel. Collectively, we revealed that HuNoV induced the production of AQP1 by activating the NF-κB signaling pathway. The findings in this study provide a basis for further understanding the significance of HuNoV-induced AQP1 expression and the potential mechanism underlying HuNoV-caused diarrhea.

Aquaporins (AQPs) are membrane-bound proteins for water transportation and are useful for diagnosing drowning and wound vitality in forensic pathology. Here, we examined intrathrombotic expression of AQP-1 and AQP-3 using deep vein thrombosis models in mice. To perform immunohistochemical analyses, we used anti-AQP-1 and anti-AQP-3 antibodies. In thrombus samples with the post-ligation intervals of 1 to 5 days, AQP-1+ areas were over 70%. At 7 days after the IVC ligation, AQP-1+ areas became less than 50%, eventually decreasing to 11% at 21 days. At 3 days after the IVC ligation, AQP-3+ cells started to appear from the peripheral area. Thereafter, the positive cell number progressively increased and reached to a peak at 10 days after the IVC ligation. When the intrathrombotic AQP-1+ area was as large as the intrathrombotic collagen area or smaller, it would indicate a thrombus age of ≥ 10 days. AQP-3+ cell number of > 30 would indicate a thrombus age of 10–14 days. Collectively, our study implied that the detection of AQP-1 and AQP-3 would be useful for the determination of thrombus age. [ABSTRACT FROM AUTHOR]

Aquaporin 1 (AQP1) is one member of the aquaporin family, also the deeply studied one. It is widely located on the endothelial cells, but the effect of AQP1 on the peritoneal mesothelial cells (PMCs) after long‐term peritoneal dialysis (PD) has not been reported before. We divided normal mice into two groups, control group and dialysis group, to confirm the fibrotic changes and expression of APQ1 on peritoneal mesothelial cells. Then we assigned normal mice and AQP1 knockout mice into four groups: Control group, normal dialysis group, AQP1 knockout control group and AQP1 knockout dialysis group. The two dialysis groups received 4.25% glucose dialysis for 28 days. We found that mice in both dialysis groups showed peritoneal fibrotic changes, which were most severe in the AQP1 knockout dialysis group; the peritoneal thickness in the AQP1 knockout dialysis group was also thicker than that in the dialysis group (P <.05). We used electron microscopy to detect ultrastructural changes and observed changes in microvilli and vacuolar degeneration in mesothelial cells from all groups except the control group. The basement membranes were damaged in the AQP1 knockout dialysis group, and peritoneal mesothelial cells were disrupted and detached in this group. Together our findings indicate that AQP1 plays an important role in maintaining the physiological functions of peritoneal mesothelial cells, and AQP1 can protect mesothelial cells during dialysis. [ABSTRACT FROM AUTHOR]

The aquaporins (AQPs) are a family of integral membrane proteins which play critical roles in controlling transcellular water movement in various tissues throughout the body. AQP1 helps mediate the cellular response to osmotic stress and tissue water permeability. However, the mechanism by which AQP1 mediates changes in cell volume is not completely clear. Here, we investigated how AQP1 responds to and controls cell volume upon osmotic stimuli during the early phase after the immediate response. Cells overexpressing AQP1 were exposed to hypotonic or hypertonic medium in the presence or absence of staurosporine or W‐7 hydrochloride, and fluorescence imaging was performed at 0, 5, 10, and 15 min later. Osmotic stimuli induced redistribution of AQP1 into the cell membrane, hypotonic stimuli caused cell enlargement, and hypertonic stimuli induced a reduction in cell size, which was blocked by T157A/T239A mutations. Changes in cell size induced by osmotic stimuli were blocked by an antagonist of calmodulin kinase, W‐7 hydrochloride, but not by the PKC inhibitor staurosporine. These results suggest that calmodulin kinase regulates AQP1 activity during the early response to osmotic stimuli. [ABSTRACT FROM AUTHOR]

Background: Aquaporins (AQPs) are transmembrane channel proteins. Aquaporin 1 (AQP1), Aquaporin 3 (AQP3), and Aquaporin 7 (AQP7) are expressed in the jejunum. The purpose of this study was to ascertain how a high-fat high-fructose diet (HFFD) and intermittent fasting (IF) affect AQP1, AQP3, and AQP7 expression in the rat jejunum., Methods: Sixteen adult male rats were divided into control rats (n = 4) fed on a basal diet and water ad libitum for 12 weeks; IF control rats (n = 4) followed the IF protocol, HFFD-fed rats (n = 8) fed HFFD for eight weeks, and rats were randomized into two groups: HFFD only or HFFD and IF protocol from the beginning of the 9th week until the end of the experiment. The lipid profile values were assessed after 12 weeks. Jejunal oxidative markers (malondialdehyde and reduced glutathione) and AQP1, AQP3, and AQP7 mRNA expression were measured. Jejunal sections were used for morphometric analysis of villus length and crypt depth. Immunohistochemical evaluation of AQP1, AQP3, and AQP7 expression was also performed., Results: IF ameliorates HFFD-induced lipid profile, oxidative stress, and jejunal morphometric changes. The results of both mRNA expression using PCR and immunohistochemistry showed a significant increase in AQP1, AQP3, and AQP7 expression in HFFD, whereas IF caused a decline in this expression., Conclusion: These findings suggest that IF can reduce inflammation, and oxidative stress and restore jejunal morphology caused by HFFD., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare that there are no financial interests or relationships — within the last 3 years — related to the subject matter. The authors declare that there are no patents or copyrights that are relevant to the work in the manuscript., (© 2024 The Authors. Published by Elsevier Ltd.)