AQP4 Protein Levels Research Articles

Extract of Nanhaia speciosa J. Compton & Schrire alleviates LPS-induced acute lung injury via the NF-κB/Nrf2/AQPs pathway

Ethnopharmacological relevanceNanhaia speciosas J. Compton & Schrire (the name Nanhaia speciosas J. Compton & Schrire has been accepted by the World Checklist of Vascular Plants https://www.worldfloraonline.org/taxon/wfo-0001444004) is a traditional Zhuang medicine that have been widely used for centuries. It has been used in the treatment of lung inflammation, tuberculosis, rheumatic pain, lumbar muscle strain, and various other ailments, such as chronic hepatitis, menoxenia, leukorrhea, and injuries. In addition, N. speciosa has also been used to treat acute lung injury (ALI). Aim of the studyThe objective of this study was to conduct a comparative analysis of the effects of various constituents present in N. speciosas extract (NSE) on ALI and the related mechanisms while also elucidating the potential active monomeric components. Materials and methodsNSE was extracted using an AB-8 macroporous resin column, and five fractions (Fr. 0%, 25%, 50%, 75% and 95%) were obtained. The anti-inflammatory and antioxidant capacities of the five fractions were evaluated in an A549 cell-based in vitro model, with the aim of evaluating their potential therapeutic effects. The anti-inflammatory and antioxidant capacities of NSE were assessed in a murine model of ALI induced by intratracheal injection of LPS. We utilized an in vitro model to analyse the critical molecular mechanisms through which NSE ameliorates ALI. The chemical composition of the optimal fraction was analysed and confirmed using UHPLC/MS. ResultsDifferent fractions (especially Fr. 75%) significantly reduced inflammation and oxidative stress in A549 cells. Fr.75% abrogated LPS-induced pathological alterations and decreased the lung W/D ratio, total protein concentration in BALF, and the levels of the proinflammatory factors TNF-α, IL-6, and IL-1β. Moreover, Fr.75% reduced MPO and MDA concentrations and elevated SOD and GSH concentrations in pulmonary tissues. Additionally, it decreased the pulmonary tissue inflammation caused by LPS by downregulating the expression of p-NF-κB p65 and upregulating the expression of Nrf2, AQP1 and AQP5. Fr. 75% decreased p-NF-κB p65 protein levels; increased Keap1, Nrf2, HO-1, NQO1, AQP1 and AQP5 protein levels; and promoted the entry of Nrf2 into the nucleus. After UHPLC/MS analysis was conducted, the flavonoid Maackiain was determined to potentially play a pivotal role in this process. ConclusionFr.75% alleviates ALI by regulating the NF-κB/Nrf2/AQPs signalling pathway. The flavonoid Maackiain may also play an important role in this process. Overall, N. speciosas may be a potential therapeutic agent for the prevention and treatment of ALI.

Effects of Modulating BMP9, BMPR2, and AQP1 on BMP Signaling in Human Pulmonary Microvascular Endothelial Cells.

Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive increase in mean pulmonary arterial pressure. Mutations in the BMPR2 and AQP1 genes have been described in familial PAH. The bone morphogenetic proteins BMP9 and BMP10 bind with high affinity to BMPR2. Administration of BMP9 has been proposed as a potential therapeutic strategy against PAH, although recent conflicting evidence dispute the effect of such a practice. Considering the involvement of the above molecules in PAH onset, progression, and therapeutic value, we examined the effects of modulation of BMP9, BMPR2, and AQP1 on BMP9, BMP10, BMPR2, AQP1, and TGFB1 expression in human pulmonary microvascular endothelial cells in vitro. Our results demonstrated that silencing the BMPR2 gene resulted in increased expression of its two main ligands, namely BMP9 and BMP10. Exogenous administration of BMP9 caused the return of BMP10 to basal levels, while it restored the decreased AQP1 protein levels and the decreased TGFB1 mRNA and protein expression levels caused by BMPR2 silencing. Moreover, AQP1 gene silencing also resulted in increased expression of BMP9 and BMP10. Our results might possibly imply that the effect of exogenously administered BMP9 on molecules participating in the BMP signaling pathway could depend on the expression levels of BMPR2. Taken together, these results may provide insight into the highly complex interactions of the BMP signaling pathway.

Network pharmacology and molecular docking-based investigation of monocyte locomotion inhibitory factor attenuates traumatic brain injury by regulating aquaporin 4 expression.

Traumatic brain injury (TBI) is a significant cause of disability and mortality worldwide, and effective treatment options are currently limited. Monocyte locomotion inhibitor factor (MLIF), a small molecular pentapeptide, has demonstrated a protective effect against cerebral ischemia. This study aimed to investigate the protective effects of MLIF on TBI and explore its underlying mechanism of action. In animal experiments, we observed that administration of MLIF after TBI reduced brain water content and improved brain edema, suggesting a certain degree of protection against TBI. By utilizing network pharmacology methodologies, we employed target screening techniques to identify the potential targets of MLIF in the context of TBI. As a result, we successfully enriched ten signaling pathways that are closely associated with TBI. Furthermore, using molecular docking techniques, we identified AQP4 as one of the top ten central genes discovered in this study. Eventually, our study demonstrated that MLIF exhibits anti-apoptotic properties and suppresses the expression of AQP4 protein, thus playing a protective role in traumatic brain injury. This conclusion was supported by TUNEL staining and the evaluation of Bcl-2, Bax, and AQP4 protein levels. These discoveries enhance our comprehension of the mechanisms by which MLIF exerts its protective effects and highlight its potential as a promising therapeutic intervention for TBI treatment.

Aquaporin 1 is a prognostic marker and inhibits tumour progression through downregulation of Snail expression in intrahepatic cholangiocarcinoma.

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.

Aquaporin 1 (AQP1)/ GSK3β interactions control pulmonary arterial smooth muscle cell (PASMC) function

Pulmonary hypertension (PH) is a complex, incurable, devastating condition, due to pathology of the pulmonary circulation. PH can be induced by hypoxia and is notable for severe wall thickening in the distal vasculature, characterized by enhanced PASMC migration and proliferation. Previously our lab discovered AQP1, a water channel, was highly expressed in PASMCs and mediated hypoxia-induced migration and proliferation. Moreover, increasing AQP1 protein was sufficient to induce PASMC migration and proliferation without hypoxia. We showed the C-terminal tail was required for regulating cell function via accumulation of β-catenin independent of water transport.β-catenin protein is tightly controlled by glycogen synthase kinase 3 β (GSK3β). Binding to GSK3β results in β-catenin degradation; when stabilized, β-catenin mediates transcription of pro-growth genes. Through in silico analysis, we identified a putative binding site for GSK3β in the AQP1 C-terminal tail, allowing us to hypothesize a potential mechanism whereby AQP1 binds GSK3β, releasing β-catenin from degradation, and thereby increases PASMC migration and proliferation.First, we used BioID, a proximity-based assay, to identify GSK3β and AQP1 interactions. We designed BioID constructs with wild-type AQP1 (BioID-AQP1) and AQP1 with mutations in the putative GSK3β binding site (BioID-AQP1M) fused to biotin ligase and compared results to wild-type AQP1 (AQP1), as a control for transfection. We used HEK293 cells which do not express endogenous AQP1. In cells transfected with AQP1 and incubated with cell permeable biotin, following biotin-affinity capture of streptavidin, no biotinylated GSK3b was measured. In cells transfected with BioID-AQP1, a significant amount of GSK3β protein was biotinylated, suggesting AQP1/GSK3β protein-protein interactions. When the putative GSK3b binding site was mutated, very low levels of GSK3b were biotinylated.Next, primary cultured rat distal PASMCs were infected with adenoviral constructs expressing wild-type AQP1 (AdAQP1), AQP1 with the putative GSK3β binding site mutated (AdAQP1M), or green fluorescent protein (AdGFP; control for infection). Compared to AdGFP, infection with AdAQP1 and AdAQP1M increased PASMC total and surface AQP1 protein levels. Using calcein self-quenching, the rate change of water influx was similar for both AQP1 constructs, indicating the mutation did not impair function as a water channel. Infection with AdAQP1 significantly increased both PASMC migration and proliferation, measured by BrdU incorporation and transwell assays, respectively, whereas infection with AdAQP1M had no effect.Our results suggest AQP1 controls PASMC migration and proliferation via a mechanism that requires GSK3β interactions. We speculate high levels of AQP1, as occur during PH, act as a sink for GSK3β, allowing β-catenin to escape from the destruction complex and facilitate cell migration and initiate gene transcription involved in cell proliferation. HL126514 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Xinshuitong Capsule extract attenuates doxorubicin-induced myocardial edema via regulation of cardiac aquaporins in the chronic heart failure rats

Doxorubicin (Dox), an effective antineoplastic drug, was limited use for cardiotoxicity. Xinshuitong Capsule (XST), a patented herbal formula, showed desirable beneficial effects in the treatment of chronic heart failure (CHF) patients. However, the drug on Dox-induced cardiotoxicity remains unclear. Ninety male Sprague-Dawley rats were randomized into two groups: 15 rats were selected as the normal group and 75 rats were injected intraperitoneally with Dox to establish CHF rat models, the success ones were randomly divided into five groups: low XST (LXST), medium XST (MXST) or high XST (HXST) (4.9, 9.8, or 19.6 g/kg d) administrated intragastrically twice a day for 4 weeks, with the captopril-treated group and the model group as comparison. The model group showed the cardiac functions generally impaired, and CHF mortality rate higher (47%) than those in the XST-treated groups (averaged 24%, P < 0.05). Compared with XST-treated groups, myocardial remodeling, inflammation and desarcomerization, and higher water content more severe in the cardiac tissue in the model group (P < 0.05), which was associated with higher expressions of mRNA or protein levels of AQP1, 4 and 7. Dox-impaired cardiac functions, cardiac remodeling and myocardial edema could be dose-dependently reverted by XST treatment. XST could inhibit AQP1, 4 and 7 at mRNA levels or at protein levels, which was associated with the attenuation of myocardial edema and cardiac remodeling, decreasing the ventricular stiffness and improving the cardiac functions and rats’ survival. AQPs is involved in cardiac edema composed one of the mechanisms of Dox-induced cardiotoxicity, XSTvia inhibition of AQPs relieved the Dox-induced side effects.

Evaluation of aquaporins in the cerebrospinal fluid in patients with idiopathic normal pressure hydrocephalus.

Brain aquaporin 1 (AQP1) and AQP4 are involved in cerebrospinal fluid (CSF) homeostasis and might participate in the origin of hydrocephalus. Studies have shown alterations of perivascular AQP4 expression in idiopathic normal pressure hydrocephalus (iNPH) and Alzheimer’s disease (AD). Due to the overlapping of clinical signs between iNPH and certain neurological conditions, mainly AD, specific biomarkers might improve the diagnostic accuracy for iNPH. The goal of the present study was to analyze and quantify the presence of AQP1 and AQP4 in the CSF of patients with iNPH and AD to determine whether these proteins can be used as biomarkers of iNPH. We examined AQP1 and AQP4 protein levels in the CSF of 179 participants (88 women) classified into 5 groups: possible iNPH (81 participants), hydrocephalus associated with other neurological disorders (13 participants), AD (41 participants), non-AD dementia (32 participants) and healthy controls (12 participants). We recorded each participant’s demographic and clinical variables and indicated, when available in the clinical history, the record of cardiovascular and respiratory complications. An ELISA showed virtually no AQP content in the CSF. Information on the vascular risk factors (available for 61 patients) confirmed some type of vascular risk factor in 86% of the patients with possible iNPH and 58% of the patients with AD. In conclusion, the ELISA analysis showed insufficient sensitivity to detect the presence of AQP1 and AQP4 in CSF, ruling out the possible use of these proteins as biomarkers for diagnosing iNPH.

Diuretic effect of Lagopsis supina fraction in saline-loaded rats is mediated through inhibition of aquaporin and renin-angiotensin-aldosterone systems and up-regulation of atriopeptin

Lagopsis supina (Steph. ex Willd.) lk. -Gal. ex Knorr. has been used as a diuretic agent in China for centuries with limited scientific evidence. This study investigated the diuretic efficacy and underlying mechanism of a macroporous adsorption resin with 30% ethanol elution fraction from L. supina (LSC) in saline-loaded rats and to identify its phytochemicals by ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-qTOF-MS/MS). As a result, 18 phenylpropanoids, 14 flavonoids and 15 others were identified in LSC, among which stachysoside A and acteoside could be the main bio-active constituents responsible for the diuretic effect. In parallel, the daily administration of LSC (16, 32 and 64 mg/kg) markedly promoted urinary excretion after 2 h of treatment. Moreover, LSC had no effect on urinary Na+ and K+ concentrations, as well as on serum Na+-K+-ATPase activity. Meanwhile, LSC significantly decreased the serum levels of angiotensin II (Ang II), anti-diuretic hormone (ADH), aldosterone (ALD), aquaporin (AQP) 1, AQP2 and AQP3, suppressed renal AQP1, AQP2, and AQP3 mRNA expressions, down-regulated AQP1, AQP2 and AQP3 protein levels, and up-regulated serum atriopeptin (ANP) level in a dose-dependent manner. These findings suggest that LSC has acute and prolonged diuretic effects by inhibiting the AQPs, RAAS, and upregulation of atriopeptin in saline-loaded rats, and this finding support LSC as a novel diuretic agent.

Influence of Alveolar Fluid on Aquaporins and Na+/K+-ATPase and Its Possible Theoretical or Clinical Significance.

Pulmonary edema is the most common pathophysiological change in pulmonary disease. Aquaporins (AQPs) and Na+/K+-ATPase play pivotal roles in alveolar fluid clearance. This study aimed to explore the influence of increased alveolar fluid on the absorption of lung fluid. Eighty New Zealand rabbits were randomly divided into eight groups (n = 10 in each group), and models of different alveolar fluid contents were established by the infusion of different volumes of normal saline (NS) via the endotracheal tube. Five animals in each group were sacrificed immediately after infusion to determine the wet/dry ratio, while the remaining animals in each group were killed 4 hours later to determine the wet/dry ratio at 4 hours. Additionally, lung specimens were collected from each group, and quantitative real-time PCR (qRT-PCR), western blot, and immunohistochemical (IHC) analyses of AQPs and Na+/K+-ATPase were performed. The qRT-PCR analysis and western blot studies showed markedly decreased mRNA and protein levels of AQP1 and Na+/K+-ATPase when the alveolar fluid volume was ≥6 mL/kg, and the mRNA level of AQP5 was significantly reduced when the alveolar fluid volume was ≥4 mL/kg. In addition, IHC analysis showed the same results. At 4 hours, the lung wet/dry ratio was significantly increased when the alveolar fluid volume was ≥6 mL/kg; however, compared with 0 hours after NS infusion, there was still a significant absorption of alveolar fluid for a period of 4 hours. The results of this study suggest that increased alveolar fluid may induce the downregulation of the mRNA and protein expression of AQPs and Na+/K+-ATPase, which appear to affect alveolar fluid clearance in rabbit lungs. Early intervention is required to avoid excessive alveolar fluid accumulation. · The expression levels of AQPs and Na+/K+--ATPase were significantly decreased as alveolar fluid increased.. · At 4 hours, wet/dry ratio was significantly increased when infusion volume was ≥ 6 mL/kg.. · Early intervention is required to avoid excessive alveolar fluid accumulation..

The chemical profiling of aqueous soluble fraction from Lagopsis supina and its diuretic effects via suppression of AQP and RAAS pathways in saline-loaded rats

Ethnopharmacological relevanceLagopsis supina (Steph.) Ik. -Gal. ex Knorr. has been widely used as a remedy treatment for diuresis and edema in China over 2500 years. Our previous results showed that the aqueous soluble fraction from L. supina (LSB) possessed acute diuretic effect. Aim of the studyThe aim of this study was to appraise the acute (6 h) and prolonged (7 d) diuretic effects, underlying mechanisms, and chemical profiling of LSB. Materials and methodsThe chemical profiling of LSB was performed by ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-qTOF-MS/MS). Then, oral administration of LSB (40, 80, 160 and 320 mg/kg) and furosemide (10 mg/kg) once daily for 7 consecutive days to evaluate the diuretic effects in saline-loaded rats. The body weight, food consumption, and water intake were recorded once daily. The urinary volume, pH and electrolyte concentrations (Na+, K+, Cl−, and Ca2+) were measured after administration drugs for acute and prolonged diuretic effects. In addition, the serum levels of Na+-K+-ATPase, angiotensin II (Ang II), anti-diuretic hormone (ADH), aldosterone (ALD), atriopeptin (ANP), aquaporins (AQPs)-1, 2 and 3 were determined by ELISA kits. The mRNA expressions and protein levels of AQPs-1, 2 and 3 were analyzed by real-time quantitative PCR and Western blot assays, respectively. Results30 compounds were identified in LSB based on accurate mass and MS/MS fragmentation compared to literature, among which phenylpropanoids and flavonoids could be partly responsible for the major diuretic effect. Daily administration of LSB (160 or 320 mg/kg) prominently increased urinary excretion volume after the 2 h at the first day of treatment, remaining until the 7th day. LSB did not cause Na+ and K+ electrolyte abnormalities, and has minor effect on Cl− and Ca2+ concentrations at 320 mg/kg. Furthermore, LSB observably suppressed renin-angiotensin-aldosterone system (RAAS) activation, including decreased serum levels of Ang II, ADH, and ALD, and prominently increased serum level of ANP in rats. LSB treatment significantly down-regulated the serum levels, mRNA expressions and protein levels of AQP1, AQP2, and AQP3. ConclusionLSB has a prominent acute and prolonged diuretic effects via suppression of AQP and RAAS pathways in saline-loaded rats, and support the traditional folk use of this plant. Taken together, LSB might be a potential diuretic agent.

Differential response of cardiac aquaporins to hyperosmotic stress; salutary role of AQP1 against the induced apoptosis.

Multiple pathophysiological conditions are associated with disturbance of myocardial osmotic equilibrium, exerting detrimental effects on cardiac performance. Cardiac myocytes may encounter hyperosmotic stress during hyperglycemia, ischemia/reperfusion injury, myocardial infarction, diabetes mellitus, severe dehydration, hypoxia or heat stress. Aquaporins (AQPs) constitute transmembrane channels that facilitate water transport in response to osmotic gradients. Therefore, the present study aimed at probing into AQPs mode of response and potential role as effector molecules and sensors, under hyperosmotic stress. H9c2 cardiac myoblasts were left untreated (control) or were exposed to 0.5 M sorbitol so as to induce hyperosmotic stress conditions. After the experimental treatments, MTT assay was performed to assess cell viability. Endogenous mRNA levels of AQP1 and AQP7 were assessed by ratiometric RT-PCR. Their subcellular localization pattern was revealed by immunofluorescence microscopy. Protein levels of AQP1 and AQP7, as well as of apoptotic markers (cleaved caspase-3 and PARP), were detected by immunoblot analysis. Hyperosmotic stress (0.5 M sorbitol) induced a time-dependent upregulation of AQP7 (but not of AQP1) mRNA in H9c2 cells. Of note, biochemical and immunocytochemical analyses revealed the increased membrane-associated protein expression of AQP1, under these conditions, while AQP7 respective levels remained unchanged. Interestingly, inhibition of AQP1 by HgCl2, aggravated the sorbitol-induced apoptosis in H9c2 cells, as evidenced by chromatin condensation and fragmentation of caspase-3 and PARP. AQP1 and AQP7 are differentially regulated under hyperosmotic stress conditions in H9c2 cells. AQP1, acting as an osmotic stress sensor and response factor, exerts a beneficial effect against the sorbitol-induced apoptosis, potentially favoring preservation of cardiac function.

Testicular AQP1 expression in a rat model of testicular Ischemia–Reperfusion injury

This study was conducted for the investigation of AQP1 expression in normal testicular tissues and those with I/R injury in a rat model. A TT rat model was established using male Wister rats (4 weeks old, 180-220g), and AQP1 distribution in the testicular tissues was detected by immunohistochemistry. The wet/dry (W/D) weight ratios of the testes were determined at 12h, 24h, 36h, 48h, or 5 days after the establishment of the TT model. At each time point, pathological sections were prepared and the mRNA and protein expression levels of AQP1 were determined by RT-qPCR and Western blotting, respectively. Immunohistochemical staining indicated that AQP1 distributes in testicular vascular endothelial cells and interstitial connective tissues. The testicular edema was observed 12 and 24h after TT, as indicated by the increase in wet/dry weight ratio and pathological changes, such as enlarged testicular interstitium, atrophy of spermatogenic tubules, and epineurium tubule exfoliation. Increase in the expression levels of Aqp1 mRNA and AQP1 protein levels peaked at 24h. Edema was alleviated at 36 and 48h, as manifested by the gradual thinning of the spermatogenic tubules epithelium with narrowed interstitium and weakened inflammatory cell infiltration. Meanwhile, the mRNA and protein levels of AQP1 dramatically decreased. At 5 days after TT, edema was nearly absent, and the mRNA and protein levels of AQP1 were restored to basal levels. Testicular torsion increases AQP1 expression and W/D ratios in testis tissues. The upregulation of AQP1 expression and decline in AQP1 level are consistent to the development and alleviation of edema in testis tissues that underwent testicular torsion. Changes in AQP1 expression were consistent with edema severity in the testes, indicating a close relationship between the expression of AQP1 and the extent of edema in testicular I/R.

Effects of Aquaporins1, ENAC Induced by Pro-b Cell Clonal Enhancer Factor on Growth, and Expression in Hypoxia/Reoxygenation Treated Human Non-Small Cell Lung Carcinoma Cells

Objective: Lung cancer (LC) remains to be the most frequent cancer among male patients, nonsmall-cell lung cancer (NSCLC) is the most common type of LC. Here we aim to investigate the effect of Pro-b cell clonal enhancer factor (PBEF) on the growth of human NSCLC cells treated with hypoxia/reoxygenation (H/R). Methods : NSCLC A549 cells were divided into four groups: (1) control group; (2) model group; (3) model+ pCAGGS no-load control group; (4) model+ pCAGGS PBEF group. PCAGGS PBEF plasmid was constructed and transfected into the cells, and the expression of PBEF was detected by qPCR and WB, H/R model was constructed, western blot (WB) was used to detect the expressions of AQP1 and ENaC , and cell apoptosis was detected by flow cytometry. Results: Cell apoptosis ratio was higher in H/R model group than that of normal control group; there was no significant difference in apoptosis ratio between the model group and the no-load control group; while the apoptosis ratio in the overexpressed PBEF group was significantly higher than that of the no-load group. AQP1 and ENaC protein levels were significantly lower in the overexpressed PBEF group than the no-load group, while there was no significant difference among normal control group, the model group and the no-load group. Conclusion: Overexpression of PBEF promotes the apoptosis of H/R human NSCLC cells and inhibites the expression of AQP1 and ENaC proteins, indicating that PBEF may play potential adjuvant therapeutic role in the treatment of NSCLC.

Sevoflurane modulates AQPs (1,5) expression and endoplasmic reticulum stress in mice lung with allergic airway inflammation.

Sevoflurane was found to show protective roles in mice with asthma, however, the mechanism of which needs further exploring. Aquaporins (AQPs) have been demonstrated to be involved in the pathogenesis of asthma, while endoplasmic reticulum stress has been reported to be related to many inflammatory diseases and involved in protein processing, including AQPs. The present study aimed to determine the role of sevoflurane in AQPs (AQP1,3,4,5) expression in mice with allergic airway inflammation and the probable mechanism. The increased number of inflammatory cells infiltrating the lung tissue, and the elevated levels of tumor necrosis factor-α (TNF-α) and interleukin (IL) 13 (IL-13) were all decreased after sevoflurane treatment (all P<0.05). Meanwhile, mRNA levels of AQP1 and AQP5 but not AQP3 and AQP4 were decreased in ovalbumin (OVA)-induced allergic mice lung. Both the decreased mRNA expression and protein levels of AQP1 and AQP5 in allergic lung tissues were reversed by sevoflurane treatment. Furthermore, we established that sevoflurane inhibited the OVA-induced protein increase in the endoplasmic reticulum (ER) stress markers BiP and C/EBP homologous protein (CHOP). Collectively, these findings suggested that sevoflurane modulated the expression and protein level of AOPs (AQP1, AQP5) as well as inhibited ER stress response in OVA-induced allergic airway inflammation of mice.

The dynamic expression of aquaporins 1 and 4 in rats with hydrocephalus induced by subarachnoid haemorrhage.

Hydrocephalus is a common complication of subarachnoid haemorrhage (SAH). As transmembrane water channels, aquaporins 1 and 4 (AQP1 and AQP4) are involved in the pathogenesis of hydrocephalus. We aimed to assess the association between the expressions of AQP1 and AQP4 and the severity and duration of hydrocephalus after SAH. A double haemorrhage model by injection of autologous blood into the cisterna magna was used to induce SAH in rats. Sham rats received the same procedures, but with the injection of normal saline. The SAH group was divided into the SAH with hydrocephalus group and SAH without hydrocephalus group after identifying hydrocephalus histologically. AQP1 and AQP4 in ventricle regions were detected by immunofluorescence, quantitative polymerase chain reaction (qPCR) and western blot. Hydrocephalus was the most severe at day 3 after SAH. AQP1 and AQP4 mRNA and protein levels increased at day 1 and peaked at day 3. The SAH with hydrocephalus group had a higher expression of AQP1 and AQP4 than the SAH without hydrocephalus group. Higher AQP1 levels were found at the apical and basolateral membrane of the choroid plexus epithelium, while higher AQP4 levels were found in the ependymal cells. A positive correlation between the relative lateral ventricle area and the ratio of AQP1/AQP4 proteins was identified. AQP1 and AQP4 are remarkably correlated with the severity of hydrocephalus induced by SAH. AQP1 and AQP4 are potential drug targets for developing therapeutic strategies against hydrocephalus.

Effect of low radiation dose on the expression and location of aquaporins in rat submandibular gland.

Head and neck cancers are common in several regions of the world and the treatment usually includes radiotherapy. This treatment can generate adverse effects to the salivary flow, with a relationship between the dose and the damage caused. Salivary gland cells are highly permeable to water and therefore, they express aquaporins (AQPs). This study analyzed changes in the expression and location of these proteins and identified morphological changes induced by low radiation in rat submandibular gland. Female rats were divided into control and irradiated groups. Immunohistochemistry analysis allowed confirming the presence of AQP1 in the blood vessel endothelium. Intense and steady labelling granules were also observed in the cytoplasm of submandibular gland ductal cells. In addition, there was AQP5 positive labelling in ductal cells delimiting the lumen of intercalated duct, in the cytoplasm and membrane of acinar cells. Finally, the decrease of AQP labelling in irradiated animal glands validated their radiosensitivity. Thus, the decrease in AQP1 protein levels in the endothelium and AQP5 in gland ductal cells of irradiated animals may have hindered the removal of water from the lumen of ductal cells, inducing a delay in water absorption and triggering a slight lumen increase.

Aquaporin expression in the fetal porcine urinary tract changes during gestation.

The expression of aquaporins (AQPs) in the fetal porcine urinary tract and its relation to gestational age has not been established. Tissue samples from the renal pelvis, ureter, bladder and urethra were obtained from porcine fetuses. Samples were examined by RT-PCR (AQPs 1-11), QPCR (AQPs positive on RT-PCR), and immunohistochemistry. Bladder samples were additionally examined by Western blotting. RNA was extracted from 76 tissue samples obtained from 19 fetuses. Gestational age was 60 (n=11) or 100 days (n=8). PCR showed that AQP1, 3, 9 and 11 mRNA was expressed in all locations. The expression of AQP3 increased significantly at all four locations with gestational age, whereas AQP11 significantly decreased. AQP1 expression increased in the ureter, bladder and urethra. AQP9 mRNA expression increased in the urethra and bladder, but decreased in the ureter. AQP5 was expressed only in the urethra. Immunohistochemistry showed AQP1 staining in sub-urothelial vessels at all locations. Western blotting analysis confirmed increased AQP1 protein levels in bladder samples during gestation. Expression levels of AQP1, 3, 5, 9 and 11 in the urinary tract change during gestation, and further studies are needed to provide insights into normal and pathophysiological water handling mechanisms in the fetus.

Hypertonic Saline Alleviates Brain Edema After Traumatic Brain Injury via Downregulation of Aquaporin 4 in Rats.

BackgroundHypertonic saline (HS) has been successfully used for treatment of various forms of brain edema. Decreased expression of aquaporin (AQP)4 and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β have been linked to edema pathogenesis. This study examined the effect of 3% HS on brain edema in a rat model of traumatic brain injury (TBI).Material/MethodsSprague-Dawley rats were subjected to TBI induced by a controlled cortical impactor. The HS group was injected with 3% NaCl until the end of the study period. AQP4, TNF-α, IL-1β, and caspase-3 levels were measured by Western blotting, immunohistochemistry, enzyme-linked immunosorbent assay, and quantitative real-time PCR. Brain water content was also measured. Apoptotic cells in brain tissue were detected with terminal deoxynucleotidyl transferase dUTP nick-end labeling. Brain water content decreased following treatment with 3% HS relative to the TBI group.ResultsThis was accompanied by decreases in AQP4, TNF-α, and IL-1β mRNA and protein levels. TBI resulted in increases in caspase-3 mRNA expression and the number of apoptotic cells; treatment with 3% HS suppressed apoptosis as compared to the TBI group.ConclusionsTreatment with 3% HS ameliorated TBI-induced brain edema, possibly by suppressing brain edema, pro-inflammatory cytokine expression, and apoptosis.

Changes in the Expression of AQP4 and AQP9 in the Hippocampus Following Eclampsia-Like Seizure.

Eclampsia is a hypertensive disorder of pregnancy that is defined by the new onset of grand mal seizures on the basis of pre-eclampsia. Until now, the mechanisms underlying eclampsia were poorly understood. Brain edema is considered a leading cause of eclamptic seizures; aquaporins (AQP4 and AQP9), the glial water channel proteins mainly expressed in the nervous system, play an important role in brain edema. We studied AQP4 and AQP9 expression in the hippocampus of pre-eclamptic and eclamptic rats in order to explore the molecular mechanisms involved in brain edema. Using our previous animal models, we found several neuronal deaths in the hippocampal CA1 and CA3 regions after pre-eclampsia and that eclampsia induced more neuronal deaths in both areas by Nissl staining. In the current study, RT-PCR and Western blotting data showed significant upregulation of AQP4 and AQP9 mRNA and protein levels after eclamptic seizures in comparison to pre-eclampsia and at the same time AQP4 and AQP9 immunoreactivity also increased after eclampsia. These findings showed that eclamptic seizures induced cell death and that upregulation of AQP4 and AQP9 may play an important role in this pathophysiological process.

Effects of Modified Zhisou Powder on Airway Mucus Production in Chronic Obstructive Pulmonary Disease Model Rats with Cold-Dryness Syndrome.

Objective. In China, the Chinese medicine formula modified zhisou powder (MZP) is commonly used to treat COPD with cold-dryness syndrome (CDSCOPD) to relieve cough and sputum. However, the underlying mechanisms of MZP on treating CDSCOPD remain to be elucidated. Methods. COPD and CDSCOPD rat models were established; MZP was given to CDSCOPD rats in the last 7 days of the 97-day model establishment. Then the rats were subjected to lung function measurement. Pathological changes in lungs were observed through paraffin section and H&E staining. The mRNA and protein levels of AQP1, 4, and 5 and Muc5AC and Muc5B in lung were determined by quantitative RT-PCR and western blotting. NE levels was determined by ELISA. Results. The impaired lung functions were observed in rats exposed to cigarette smoke. Among all parameters evaluating lung functions, only tidal volume demonstrates a further decrease in CDSCOPD when compared with COPD, indicating further impaired pulmonary ventilation functions upon cold-dryness stimulation. The intervention of MZP effectively improved lung functions parameters, prevented the inflammations, and eliminated the increases of AQP4 and 5 and the decrease of Muc5AC in lung. Conclusion. MZP probably improves pulmonary functions in CDSCOPD through inhibiting lung inflammation, increasing expressions of AQPs, and decreasing Muc5AC expression in lung.