AQP1 Research Articles

The water channels aquaporin-1 and aquaporin-3 interact with and affect the cell polarity protein Scribble in 3D in vitro models of breast cancer.

Cellular changes in carcinomas include alterations in cell proliferation, cell migration, cell-cell adhesion, and cellular polarity. In vitro studies have revealed that the water channels, aquaporin-1 (AQP1) and AQP3, can influence cell migration and cell-cell adhesion. Of note, we previously showed that AQP1 overexpression reduced levels of cell-cell adhesion proteins, whereas AQP3 increased levels when overexpressed in normal epithelial cells. Expression of AQP1 and AQP3 in breast carcinoma is associated with lymph node metastasis, recurrence, and poor survival of patients with breast cancer. In this study, we investigated if AQP1 and AQP3 affected cell polarity in breast cancer by studying the relationship between the major polarity protein Scribble and AQP1 and AQP3. In breast cancer tissue samples, the protein expression of AQP1, AQP3, and Scribble did not show an obvious correlation. However, in a GST pull-down assay, AQP1 and AQP3 interacted with Scribble. AQP1 overexpression reduced the size of 3D spheroids as well as reduced Scribble levels at cell-cell contacts, whereas AQP3 overexpression showed no significant change in spheroid size compared with control, AQP3 overexpression also reduced Scribble levels at cell-cell contacts. Of note, AQP1 overexpression increased cell migration and induced cell detachment and dissemination from migrating breast cancer cell sheets, whereas AQP3 overexpression did not. Thus, AQP1 and AQP3 differentially affect 3D-grown breast cancer spheroids, and especially AQP1 may contribute to cancer development and spread via negatively affecting cellular junctions and cell polarity proteins as well as increasing cell migration and cell detachment.NEW & NOTEWORTHY Overexpression of the water channels aquaporin-1 and aquaporin-3 reduced levels of the key polarity protein Scribble at cell-cell junctions, suggesting potential implications in breast cancer progression and metastasis.

Agmatine alleviates diabetic-induced hyposalivation in rats: A histological and biochemical study

Diabetic patients commonly experience hyposalivation, which can cause challenges with eating, swallowing, dry mouth, and speaking. It also raises the likelihood of developing periodontal disease. This study aimed to evaluate if agmatine could improve the rate of salivation in rats with hyposalivation induced by streptozotocin (STZ). Five groups of Wistar rats were utilized with 10 animals in each group. They were classified as follows; Negative control group (G1), agmatine (G2) group, and Nicotinamide (NA)-STZ (G3) group; received a single intraperitoneal dose of 65 mg/kg of STZ after NA injection. NA was administered to protect residual β cells and enhance their insulin secretion; NA-STZ + Metformin (G4) Metformin-treated diabetic group; at day 10 diabetic rats received 50mg/kg orally for 28 days, and NA-STZ + Agmatine (G5) at day 10 diabetic rats received a daily intraperitoneal dose of 300 mg/kg Agmatine for 28 days. The salivary flow rate was assessed weekly. Then, the animals were euthanized, both parotid (PG) and submandibular (SMG) salivary glands were dissected, and the following parameters were assessed; salivary glands' histopathology, aquaporin 5 (AQP5), caspase-3, E-cadherin expressions, inflammatory markers and finally, salivary glands' oxidative stress status. Agmatine has alleviated the salivary glands' dysfunction in STZ-induced diabetic rats. It normalized diabetes mellitus-associated salivary glands' abnormalities including histopathological abnormalities, decreased AQP5 and E-cadherin expressions, increased caspase-3 expression, and oxidative stress and inflammatory parameters. Agmatine alleviates diabetes mellitus-associated hyposalivation. It can promote PGs and SMGs function through its histological and AQP5 expression improvements.

Protective effect and mechanism of CoQ10 in mitochondrial dysfunction in diquat-induced renal proximal tubular injury.

Coenzyme Q10 (CoQ10) plays an important role in improving mitochondrial function and has many beneficial effects on the kidney. However, whether CoQ10 protects against diquat (DQ)-induced acute kidney injury (AKI) remains unclear. In this study, we investigated the protective effects and mechanism of action of CoQ10 against DQ-induced AKI. Institute of Cancer Research (ICR) mice were intraperitoneally injected with DQ to induce AKI. The expression levels of serum creatinine (Cr), urea, and kidney injury molecule-1 (KIM-1) increased, those of aquaporin 1 (AQP-1) decreased, and those of mitochondrial reactive oxygen species (ROS) increased with increased depolarization of mitochondrial membranes and mitochondrial rupture. In contrast, treatment with CoQ10 significantly improved DQ-induced AKI. CoQ10 treatment reduced serum Cr, urea, and KIM-1 contents, increased the AQP-1 expression, and reduced ROS contents in mice with DQ poisoning. Our results suggest that AKI caused by DQ poisoning may be related to the disruption of mitochondrial homeostasis and that CoQ10 treatment protects against AKI caused by DQ poisoning by improving mitochondrial kinetic homeostasis. Thus, CoQ10 represents a new therapeutic option for the prevention and treatment of AKI caused by DQ poisoning.

Multifunctional extracellular vesicles and edaravone-loaded scaffolds for kidney tissue regeneration by activating GDNF/RET pathway

With the severity of chronic kidney disease worldwide, strategies to recover renal function via tissue regeneration provide alternatives to kidney replacement therapy. To exclude side effects from direct cell transplantation, extracellular vesicles (EVs) are great substitutes representing paracrine cell signaling. To build three-dimensional structures for implantation into the 5/6 nephrectomy model by incorporating bioactive materials, including multifunctional EVs (mEVs), porous PMEZE/mEV scaffolds were developed in combination with edaravone (EDV; E) and mEV based on PMEZ scaffolds with PLGA (P), MH-RA (M), ECM (E), ZnO-ALA (Z). The oxygen free radical scavenger EDV was incorporated to induce tubular regeneration. mEVs were engineered to serve regenerative activities with a combination of two EVs from SDF-1α overexpressed tonsil-derived mesenchymal stem cells (sEVs) and intermediate mesoderm (IM) cells during differentiation into kidney progenitor cells (dEVs). mEVs displayed beneficial effects on regeneration by facilitating migration and inducing differentiation of surrounding stem cells, and EDV improved kidney function by regulating the GDNF/RET pathway and their downstream genes. The promotion of MSC recruitment was confirmed with sEV particles number dependently, and the regulation of the GDNF/RET pathway by the effect of EDV and its enhanced effect by mEVs were elucidated using in vitro analysis. The regeneration of tubules was additionally demonstrated through the increased expression of aquaporin-1 (AQP-1) and cadherin-16 (CDH16) for proximal tubules, and calbindin and PAX2 for distal tubules in the renal defect model. With these, structural regeneration and functional recovery were achieved with kidney regeneration in the 5/6 nephrectomy mice model.Graphical abstract

Expression of AQP8 in Serum of Patients With Meniere's Disease and Its Value in Evaluating the Degree of Hydrolabyrinth and Predicting Prognosis.

This study aims to explore the role of serum aquaporin 8 (AQP8) expression in evaluating the degree of hydrolabyrinth and predicting prognosis in patients with Meniere's disease. One hundred and five patients diagnosed with Meniere's disease in our hospital were enrolled in the Meniere's disease group. Another 102 healthy subjects were enrolled as the control group. The expression of serum AQP8 mRNA was determined by the quantitative real-time PCR (qRT-PCR) method. Receiver operating characteristic (ROC) curve analysis was carried out to analyse the predictive value of serum AQP8 mRNA expression for poor prognosis in Meniere's disease patients. Multivariate logistic regression was used to analyse the influencing factors of poor prognosis in patients with Meniere's disease. The expression level of serum AQP8 mRNA in the Meniere's disease group was significantly higher than that in the control group (p < 0.05). In the severe hydrops group, serum AQP8 mRNA expression levels were higher than in the mild hydrops group and the no endolymphatic hydrops group. Additionally, the mild hydrops group had higher serum AQP8 mRNA levels than the no endolymphatic hydrops group (p < 0.05). The disease course, proportion of severe hydrops and serum AQP8 mRNA expression were all higher in the poor prognosis group compared to the good prognosis group (p < 0.05). The area under the curve (AUC) for serum AQP8 mRNA in predicting poor prognosis in Meniere's disease patients was 0.812 (95%CI: 0.702-0.922). AQP8 mRNA is associated with the degree of hydrolabyrinth in patients with Meniere's disease and plays an important role in predicting prognosis.

Hypoxia reduces mouse urine output via HIF1α–mediated up–regulation of renal AQP1

Introduction: Patients with acute mountain sickness (AMS) due to hypoxia at high altitudes often exhibit abnormal water metabolism. Hypoxia-inducible factors (HIFs) are major regulators of adaptive responses to hypoxia. As transcription factors, HIFs are involved in the regulation of erythropoiesis, iron metabolism, angiogenesis, energy metabolism, and cell survival by promoting the transcriptional expression of hundreds of target genes. Roxadustat, a novel drug for the treatment of anemia associated with chronic kidney disease, acts by inhibiting the degradation of HIFs to increase their protein levels. However, the clinical use of roxadustat is frequently associated with peripheral edema, suggesting the involvement of HIFs in regulating the body's water balance possibly by modulating water reabsorption in the kidney. Methods: we first evaluated the effect of hypoxia (8% O2) on mouse urine output. We then performed in vitro experiments using hypoxia (1% O2) and roxadustat on mouse primary proximal tubular cells (mPTCs). The qPCR, western blot, and immunofluorescence were used to assess AQP1 mRNA and protein expression levels. Luciferase, CHIP, and EMSA were used to investigate the transcriptional regulation of AQP1 by HIF1α. Results: We found that mice exposed to hypoxia (8% O2) had significantly reduced urine volume compared to mice exposed to normoxia (21% O2). Hypoxia significantly elevated AQP1 expression at both mRNA and protein levels. In vitro experiments using mouse primary cultured proximal tubular cells (mPTCs) revealed that both hypoxia and roxadustat increased AQP1 expression. Mechanistically, overexpression of HIF1α, but not HIF2α, markedly increased AQP1 protein expression. Furthermore, the up-regulation of AQP1 by hypoxia and roxadustat can be blocked by the HIF1α inhibitor PX-478 in mPTCs. Finally, we found that the AQP1 gene promoter contains a putative hypoxia response element (HRE) and confirmed that AQP1 is a target gene of HIF1α using Luciferase reporter, CHIP, and EMSA assays. Conclusion: This study demonstrates that hypoxia can reduce the urine volume of mice via upregulating AQP1 expression by HIF1α in the proximal tubular epithelial cells. Our findings also suggest a potential mechanism involved in water metabolism disorders in patients with AMS and in patients with chronic kidney disease (CKD) receiving roxadustat treatment.

Detection of renal tubular transporter proteins in canine urinary extracellular vesicles using liquid chromatography-tandem mass spectrometry.

Urinary extracellular vesicles (UEVs) are membranous particles that carry renal tubular transporter proteins. Here, we evaluate whether selected renal tubular transporter proteins can be detected in UEVs isolated from small volume (1-5 mL) canine urine samples of healthy dogs and canine patients with elevated circulating parathyroid hormone (PTH)/PTH-related peptide (PTHrp) concentrations, hypercortisolism, and primary hypoadrenocorticism using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total creatinine content of each urine sample was calculated from urine volume and creatinine concentration. UEVs were isolated by size exclusion chromatography prior to quantification by nanoparticle tracking analysis and proteomic analysis by LC-MS/MS. Group comparisons were made using non-parametric statistics. Aquaporin-2 (AQP2) and the renal sodium/phosphate co-transporter (NPT2A) were detected in UEVs isolated from small volume samples of almost all healthy dogs but were not detected in most dogs with elevated circulating PTH/PTH related peptide (PTHrp) concentrations, hypercortisolism and primary hypoadrenocorticism. Total creatinine content of the urine sample was strongly positively correlated with the number of UEVs (rs = .84, P < .001); thus, total creatinine was used as a surrogate marker of UEV number. In healthy dogs, AQP2 and NPT2A were both detected in samples containing at least 1.7 × 109 UEVs or 24 μmol creatinine, however in non-healthy dogs, AQP2 and NPT2A were not detected in most samples containing up to 6.3 × 109 UEVs or 32 μmol creatinine.

Involvement of aquaporins in Shiga toxin-induced swelling and water transport dysfunction in human renal microvascular endothelial cells

One of the hallmarks of Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is kidney damage. Our previous research demonstrated that Shiga toxin type 2 (Stx2a) decreases cell viability and induces swelling of human glomerular endothelial cells (HGEC). However, Stx2a can disrupt net water transport across HGEC monolayers without affecting cell viability. This work aimed to elucidate the possible mechanisms involved in the water transport disruption caused by Stx2a across HGEC monolayers. We investigated paracellular and transcellular water transfer across HGEC by analyzing the passage of FITC-Dextran and the hydrostatic pressure (Phydr) and measuring the osmotic pressure (Posm), respectively. Stx2a selectively affected the transcellular pathway without impacting the paracellular route. Furthermore, Stx2a cell swelling was prevented by pretreatment with aquaporin inhibitors tetraethylammonium chloride (TEA), Mercury (II) chloride (HgCl2) or TGN-020, suggesting aquaporin involvement in this process. Confocal microscopy revealed that Stx2a increased HGEC total volume, which TEA and TGN-020 counteracted. Additionally, we identified in HGEC not only the expression of aquaporin-1 (AQP1) but also the expression of aquaporin-4 (AQP4). Surprisingly, we observed a decrease in the expression of both AQPs after Stx2a exposure. Our findings suggest that Stx2a may induce water movement into HGEC via AQP1 and AQP4, increasing total cell volume. Subsequently, decreased AQP1 and AQP4 expression could inhibit transcellular water transfer, potentially as a protective mechanism against excessive water entry and cell lysis.

Astragaloside IV and cycloastragenol promote liver regeneration through regulation of hepatic oxidative homeostasis and glucose/lipid metabolism

BackgroundThe regenerative capacity of the liver is pivotal for mitigating various forms of liver injury and requires the rapid proliferation of hepatocytes. Aquaporin-9 (AQP9) provides vital support for hepatocyte proliferation by preserving hydrogen peroxide (H2O2) oxidative balance and glucose/lipid metabolism equilibrium within hepatocytes. Our previous study demonstrated that Radix Astragali (RA) decoction promotes liver regeneration by upregulating hepatic expression of AQP9, possibly via two major active constituents: astragaloside IV (AS-IV) and cycloastragenol (CAG). PurposeTo verify that upregulated AQP9 expression in hepatocytes maintains liver oxidative balance and glucose/lipid metabolism homeostasis, and is the main pharmacological mechanism by which AS-IV and CAG promote liver regeneration. Study Design/MethodsEffects of AS-IV and CAG on liver regeneration were scrutinized using a mouse model of 70 % partial hepatectomy (PHx). AQP9-targeted liver regeneration mediated by AS-IV and CAG was verified using AQP9 gene knockout mice (AQP9−/−). The AQP9 protein expression pattern in hepatocytes was determined using tdTomato-tagged AQP9 transgenic mice (AQP9-RFP). Potential mechanisms of AS-IV and CAG on liver regeneration were studied using real-time quantitative PCR, immunoblotting, staining with hematoxylin and eosin, oil red O, and periodic acid-Schiff, and immunofluorescence, immunohistochemistry, HyPerRed fluorescence, and biochemical analyses. ResultsAS-IV and CAG promoted substantial liver regeneration and increased hepatic AQP9 expression in wild-type mice (AQP9+/+) following 70 % PHx, but had no discernible benefits in AQP9−/- mice. Both saponin compounds also helped maintain oxidative homeostasis by reducing levels of oxidative stress markers (reactive oxygen species [ROS], H2O2, and malondialdehyde) and elevating levels of ROS scavengers (glutathione and superoxide dismutase) in AQP9+/+ mice post-70 % PHx. This further activated the PI3K-AKT and insulin signaling pathways, thereby fostering liver regeneration. Furthermore, AS-IV and CAG both promoted hepatocyte glycerol uptake, increased gluconeogenesis, facilitated lipolysis, reduced glycolysis, and inhibited glycogen deposition, thus ensuring the energy supply required for liver regeneration. ConclusionThis research is the first to demonstrate AS-IV and CAG as major active ingredients of RA that promote liver regeneration by upregulating hepatocyte AQP9 expression, improving hepatocyte glucose/lipid metabolism, and reducing oxidative stress damage, constituting a crucial pharmacological mechanism underlying the liver-protective effects of RA. The augmentation of hepatocyte AQP9 expression underscores an important aspect of the Qi-tonifying effect of RA. This study establishes AQP9 as an effective target for regulation of liver regeneration and provides a universal strategy for clinical drug intervention aimed at enhancing liver regeneration.

Saccharomyces boulardii Mitigates Fructose-Induced Non-Alcoholic Fatty Liver in Rats.

Background and Objectives: Non-alcoholic fatty liver disease (NAFLD) is a growing global health concern closely linked to metabolic disorders, including obesity, insulin resistance, and dyslipidemia. Emerging evidence suggests that the gut-liver axis plays a critical role in the pathogenesis of NAFLD, with recent research highlighting the influence of gut microbiota, including fungal species such as Saccharomyces boulardii (S. boulardii). This study aimed to evaluate the effects of S. boulardii on lipid metabolism and oxidative stress in a rat model of fructose-induced NAFLD. Materials and Methods: Thirty Wistar rats were divided into three groups: a control group, a fatty liver group induced by 35% fructose supplementation, and a treatment group receiving S. boulardii (100 mg/kg/day) after fructose induction. Results: Biochemical analyses revealed that the treatment group exhibited significantly lower plasma levels of malondialdehyde (MDA), alanine aminotransferase (ALT), total triglycerides, and cholesterol compared to the untreated fatty liver group (p < 0.05). Furthermore, liver tissue analysis showed a marked reduction in lipid accumulation and fatty infiltration in the treatment group, with no visible lipid vacuoles in hepatocytes. The expression of aquaporin-8 (AQP8) and sirtuin-1 (SIRT1), key markers associated with hepatocyte function and lipid metabolism, was significantly higher in the S. boulardii group compared to the fatty liver group (p < 0.001). Conclusions: These findings indicate that S. boulardii supplementation mitigates the metabolic and oxidative stress-related alterations associated with fructose-induced NAFLD. In conclusion, our study suggests that S. boulardii exerts protective effects on the liver by reducing lipid accumulation and oxidative stress, highlighting its potential as a therapeutic intervention for NAFLD.

Apigenin alleviates Sjögren’s syndrome-induced salivary gland epithelial cell ferroptosis via ERα signaling-mediated regulation of the ATF3/SLC7A1l axis

BackgroundIn Sjögren’s syndrome (SS)—an autoimmune disease characterized by dry mouth and eyes—salivary gland epithelial cells (SGECs) undergo ferroptosis, which disrupts their integrity and impairs saliva secretion. Apigenin, a phytoestrogen, is known to activate estrogen signalling and alleviate xerostomia in ovariectomized mice; however, its effect on SGEC survival and function in SS remains unclear. We hypothesized that apigenin alleviates SS symptoms and progression by inhibiting ferroptosis in SGECs and aimed to elucidate the underlying mechanism. MethodsApigenin (50 mg/kg) was orally gavaged to non-obese diabetic (NOD)/LtJ female mice (SS model); changes in SS functional indicators were analyzed using mRNA sequencing and bioinformatic analyses of submandibular glands. Interferon-gamma (IFN-γ)-stimulated SGECs were used to model SS in vitro; SGEC activity and aquaporin 5 (AQP5) expression were analyzed. Immunohistochemical staining, transmission electron microscopy, RT-qPCR, western blotting and other methods were used to verify the mechanisms. ResultsApigenin significantly increased salivary secretion and AQP5 expression while inhibiting ferroptosis and immune infiltration in NOD mouse submandibular glands. The oxidative stress gene ATF3 was upregulated and GPX4 was downregulated in NOD mice compared to that in control group (ICR mice); however, apigenin reversed this effect. IFN-γ treatment downregulated AQP5, SLC7A11, and GPX4 expression while promoting ATF3 expression and ferroptosis, which was mitigated by apigenin. ATF3 knockdown increased SLC7A11 and GPX4 expression, inhibiting SS and ferroptosis. Furthermore, apigenin inhibited ferroptosis in SGECs through ESR1 binding to ATF3. ConclusionApigenin alleviates SS by regulating SGEC ferroptosis via the ERα-regulated ATF3/SLC7A11 axis, highlighting its therapeutic potential in SS.

Focal Adhesion Kinase (FAK) inhibition induces membrane accumulation of aquaporin2 (AQP2) through endocytosis inhibition and actin depolymerization in renal epithelial cells.

Cellular trafficking of the water channel aquaporin 2 (AQP2) is regulated by the actin cytoskeleton in collecting duct principal cells (PC) to maintain proper water balance in animals. Critical actin depolymerization/polymerization events are involved in both constitutive AQP2 recycling, and the pathway stimulated by vasopressin receptor signaling. Focal adhesion kinase (FAK) plays an important role in modulating the actin cytoskeleton through inhibiting small GTPases, and multiple studies have shown the involvement of FAK in insulin and cholesterol trafficking through actin regulation. To understand whether FAK contributes to water reabsorption by the kidney, we performed a series of in vitro experiments to examine the involvement of FAK and its signaling in mediating AQP2 trafficking in cultured renal epithelial cells. Our data showed that FAK inhibition by specific inhibitors caused membrane accumulation of AQP2 in AQP2expressing LLCPK1 cells by immunofluorescence staining. AQP2 membrane accumulation induced by FAK inhibition is associated with significantly reduced endocytosis of AQP2 via the clathrin-mediated endocytosis pathway. Moreover, AQP2 membrane accumulation induced by FAK inhibition also occurred in cells expressing the constitutive dephosphorylation mutant of AQP2, S256A. This was confirmed by immunoblotting using a specific antibody against phospho-serine 256 AQP2, supporting a phosphorylation independent mechanism. Finally, we demonstrated that inhibition of FAK caused reduced RhoA signaling and promoted F-actin depolymerization. In conclusion, our study identifies FAK signaling as a pathway that could provide a novel therapeutical avenue for AQP2 trafficking regulation in water balance disorders.

Development and Validation of a Comprehensive Prognostic and Depression Risk Index for Gastric Adenocarcinoma

Depressive disorder contributes to the initiation and prognosis of patients with cancer, but the interaction between cancer and depressive disorder remains unclear. We generated a gastric adenocarcinoma patient-derived xenograft mice model, treated with chronic unpredictable mild stimulation. Based on the RNA-sequence from the mouse model, patient data from TCGA, and MDD-related (major depressive disorder) genes from the GEO database, 56 hub genes were identified by the intersection of differential expression genes from the three datasets. Molecular subtypes and a prognostic signature were generated based on the 56 genes. A depressive mouse model was constructed to test the key changes in the signatures. The signature was constructed based on the NDUFA4L2, ANKRD45, and AQP3 genes. Patients with high risk-score had a worse overall survival than the patients with low scores, consistent with the results from the two GEO cohorts. The comprehensive results showed that a higher risk-score was correlated with higher levels of tumor immune exclusion, higher infiltration of M0 macrophages, M2 macrophages, and neutrophils, higher angiogenetic activities, and more enriched epithelial–mesenchymal transition signaling pathways. A higher risk score was correlated to a higher MDD score, elevated MDD-related cytokines, and the dysfunction of neurogenesis-related genes, and parts of these changes showed similar trends in the animal model. With the Genomics of Drug Sensitivity in Cancer database, we found that the gastric adenocarcinoma patients with high risk-score may be sensitive to Pazopanib, XMD8.85, Midostaurin, HG.6.64.1, Elesclomol, Linifanib, AP.24534, Roscovitine, Cytarabine, and Axitinib. The gene signature consisting of the NDUFA4L2, ANKRD45, and AQP3 genes is a promising biomarker to distinguish the prognosis, the molecular and immune characteristics, the depressive risk, and the therapy candidates for gastric adenocarcinoma patients.

Aquaporin-1 Facilitates Macrophage M1 Polarization by Enhancing Glycolysis Through the Activation of HIF1α in Lipopolysaccharide-Induced Acute Kidney Injury.

This study aimed to investigate how aquaporin 1 (AQP1) modulates hypoxia-inducible factor-1α (HIF1α) to promote glycolysis and drive the M1 polarization of macrophages. Within 12 h post-treatment with LPS to induce acute kidney injury in rats, a significant upregulation of AQP1 and HIF1α protein levels was noted in serum and kidney tissues. This elevation corresponded with a decrease in blood glucose concentrations and an enhancement of glycolytic activity relative to the control group. Furthermore, there was a pronounced reduction in the circulating levels of the anti-inflammatory cytokine IL-10, accompanied by an upregulation in the levels of the pro-inflammatory cytokines IL-6 and TNF-α. The administration of an HIF1α inhibitor reversed these effects, which did not affect the production of AQP1 protein. In cellular assays, AQP1 knockdown mitigated the increase in HIF1α expression induced by LPS. Furthermore, the suppression of HIF1α with PX-478 led to decreased expression levels of Hexokinase 2 (HK2) and Lactate Dehydrogenase A (LDHA), indicating that AQP1 regulates glycolysis through HIF1α. M1 polarization of macrophages was reduced by AQP1 knockdown and was further diminished by the addition of an HIF1α inhibitor. Inhibition of the glycolytic process not only weakened M1 polarization but also promoted M2 polarization, thereby reducing the release of inflammatory cytokines. These findings provide a novel perspective for developing therapeutic strategies that target AQP1 and HIF1α, potentially improving the treatment of sepsis-associated AKI.

Disruption of mitochondrial electron transport impairs urinary concentration via AMPK-dependent suppression of aquaporin-2.

Urinary concentration is an energy-dependent process that minimizes body water loss by increasing aquaporin-2 (AQP2) expression in collecting duct (CD) principal cells. To investigate the role of mitochondrial (mt) ATP production in renal water clearance, we disrupted mt electron transport in CD cells by targeting ubiquinone (Q) binding protein QPC (UQCRQ), a subunit of mt complex III essential for oxidative phosphorylation. QPC-deficient mice produced less concentrated urine than controls, both at baseline and after type 2 vasopressin receptor stimulation with desmopressin. Impaired urinary concentration in QPC-deficient mice was associated with reduced total AQP2 protein levels in CD tubules, while AQP2 phosphorylation and membrane trafficking remained unaffected. In cultured inner medullary CD cells treated with mt complex III inhibitor antimycin A, the reduction in AQP2 abundance was associated with activation of 5' adenosine monophosphate-activated protein kinase (AMPK) and was reversed by treatment with AMPK inhibitor SBI-0206965. In summary, our studies demonstrated that the physiological regulation of AQP2 abundance in principal CD cells was dependent on mt electron transport. Furthermore, our data suggested that oxidative phosphorylation in CD cells was dispensable for maintaining water homeostasis under baseline conditions, but necessary for maximal stimulation of AQP2 expression and urinary concentration.

Gene expression analysis of Aquaporin genes in ruminants during growth phase in response to heat stress

Aquaporins (AQPs) are trans-membrane protein involved in water transport and different cellular functions such as cell adhesion, signalling and proliferation. These membrane proteins are essential for key physiological functions such as organ development, osmoregulation, tissue regeneration and metabolism. The regulation of AQP5 gene expression in ruminants during growth phase has not been analysed in-vivo. Therefore, the gene expression pattern was analysed in Jamunapari goats during 3 months to 12 month of age and adult age group in response to heat stress. The genotyping of the AQP5 gene was carried out by High-Resolution Melting (HRM) in four different goat breeds, which indicated four distinct genotypes in the population. The nucleotide diversity for the AQP5 gene ranged from 0.315 and 0.524 across the breeds. Additionally, a close evolutionary relationship between AQP5 and the HSP70 gene was observed, indicating a shared pathway for heat stress regulation. The m-RNA expression level of AQP5 at 3, 9, 12 month and adult age group exhibited 47.24, 1140, 43.17 and 12.55-fold higher expression than control. The m-RNA expression level of the AQP5 gene was up-regulated and significantly higher (P < 0.05) at 9-month age as compared to the other age groups. Heat stress phenotypes were classified based on respiration rate and heart rate, and the m-RNA expression of AQP5 was higher in heat stress-susceptible (HSS) individuals than heat stress-tolerant (HST) individuals at 3, 9, and 12 months of age. The AQP5 plays a significant role in thermoregulation during growth phases in response to heat stress in goats, however, it is required to understand the role of aquaporins at cellular level as well as to establish the association with production performance in ruminant system in-vivo.

Evaluation of the Choroid Plexus Epithelium Inflammation TLR4/NF-κB/NKCC1 Signal Pathway Activation in the Development of Hydrocephalus.

Hydrocephalus is characterized by secretion, circulation, and absorption disorder of cerebrospinal fluid (CSF) with high morbidity and complication rate. The relationship between inflammation and abnormal secretion of CSF by choroid plexus epithelium (CPE) had received more attention. In this study, we aim to detect the role of Toll-like receptor 4/nuclear factor-kappa B/Na+/K+/2Cl-cotransporter 1(TLR4/NF-κB/NKCC1) signal pathway in the development of hydrocephalus. Hydrocephalus was induced in adult rats (8 weeks) by intracisternal kaolin injection, then pyrrolidinedithiocarbamate (PDTC) and bumetanide were administrated to the rats mode. Then the rat model was evaluated, and ventricular volume was calculated at different time points. Then CPE, cortex, preventricular tissue, and CSF were obtained. Protein expressions of TLR-4, NKCC/serine-threonine STE20/SPS1-related, proline-alanine-rich kinase (SPAK), pNKCC1, pSPAK, GFAP, AQP1, and AQP4 were measured by RT-PCR, western blot, and immunofluorescence (IF) stains in CPE, respectively. Our data showed that inflammation factors tumor necrosis factor-(TNF-α), interleukin 18(IL-18), and glial fibrillary acidic protein (GFAP) concentrations were significantly higher in the model group than in controls. The TLR4/NF-κB/NKCC1 signal pathway were actived by NF-κB-p65, NKCC1, pNKCC1- pSPAK complex, and Aquaporin1 (AQP1) high expression. PDTC and bumetanide use can help regular TLR4/NF-κB/NKCC1 expression and reduced AQP1 expression by down-regulate NF-B-p65 and inhibiting NKCC1, respectively. As a result, the treatment groups alleviated CPE abnormal secretion and ventricle enlargement. These results confirmed that the inflammatory reaction contributes TLR4/NF-κB/NKCC1 mediated CPE abnormal secretion and consequent hydrocephalus. Regulation of TLR4/NF-κB/NKCC1 and AQP1 can prevent this process. Our study provides a strong rationale for further exploring alleviating CPE abnormal secretion as a therapeutic perspective of hydrocephalus.

Tolvaptan and the role of kidney aquaporin-2 abundance in managing volume overload in patients with CKD

ABSTRACT Objective This retrospective study evaluated tolvaptan's efficacy, safety, and predictive indicators in managing volume overload in chronic kidney disease (CKD) patients. Methods CKD patients with volume overload, treated with loop diuretics alone or with tolvaptan at Zhongda Hospital, Southeast University, from 1 March 2022 to 31 December 2023, were included. Patients were divided into loop diuretic (Group C) and loop diuretic combined with tolvaptan (Group T) cohorts. Primary outcomes included volume control, changes in weight, urine output, and laboratory parameters within 1 week post-medication. Adverse events such as hypernatremia and hyperkalemia, etc., were recorded. We further conducted immunohistochemical staining of renal biopsy tissues to investigate the roles of aquaporin-2 (AQP2) in the collecting duct and plasma albumin in predicting the efficacy of tolvaptan. Results Of 174 CKD patients with volume overload, 108 (67.07%) were male. Group C and Group T each comprised 87 patients. At baseline, no significant differences in urine output and weight were noted. By day 3, Group T exhibited a greater increase in urine output (P &amp;lt; .001) and weight reduction (P &amp;lt; .001). At day 7, Group T maintained more significant diuretic effects (P &amp;lt; .001). More Group C patients required ultrafiltration therapy (P = .040). Adverse event rates did not significantly differ. Notably, AQP2 expression in the collecting duct may predict tolvaptan responsiveness, while plasma albumin did not affect efficacy. Conclusion Tolvaptan showed efficacy and safety in managing volume overload in CKD patients. The expression of AQP2 in the collecting duct could predict tolvaptan's efficacy. This study protocol was approved by the Ethics Committee of Zhongda Hospital Affiliated to Southeast University (Approval No. 2023ZDSYLL180-P01, Clinical Trial Registration No. ChiCTR2300075274, Trial Registration Link: https://www.chictr.org.cn/guide.html).

Use of multiparametric MRI to noninvasively assess iodinated contrast-induced acute kidney injury

PurposeTo gauge the utility of multiparametric MRI in characterizing pathologic changes after iodinated contrast-induced acute kidney injury (CI-AKI) in rats. MethodsWe randomly grouped 24 rats injected with 8 g iodine/kg of body weight (n = 6 each) and 6 rats injected with saline as controls. All rats underwent T1, T2 mapping and diffusion kurtosis imaging (DKI) after contrast injection at 0 (control), 1, 3, 7, 13 days. T1, T2, and mean kurtosis (MK) values were performed in renal outer/inner stripes of outer medulla (OSOM and ISOM) and cortex (CO), and their diagnosis performance for CI-AKI also been evaluated. Serum creatinine (SCr), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor metalloproteinase 2 (TIMP-2), aquaporin-1 (AQP1), α-smooth muscle actin (α-SMA), and histologic indices were examined. ResultsCompared with controls, urinary concentrations of both TIMP-2 and IGFBP7 were obviously elevated from Day 1 to Day 13 (all p < 0.05). T2 values were significantly higher than control group for Days 1 and 3, and T1 and MK increased were more remarkable at all time points (Days 1–13) in CI-AKI (all p < 0.05) than control group. Changes in T1 and MK strongly correlated with renal injury scores of all anatomical compartments and with expression levels of AQP1 and moderately correlated with α-SMA. Changes in T2 values correlating moderately with renal scores of CO, ISOM and OSOM and AQP1. The MK obtained the highest area under the receiver operating characteristic (ROC) curve of 0.846 with a sensitivity of 70.8 % and specificity of 88.9 %. ConclusionsCombined use of multiparametric MRI could be a valid noninvasive method for comprehensive monitoring of CI-AKI. Among these parameters, MK may achieve the best diagnostic performance for CI-AKI.

Dietary supplementary with ellagic acid improves the intestinal barrier function and flora structure of broiler chicken challenged with E. coli K88

Ellagic acid (EA) contributes to the immunity and anti-oxidant function of body, whereas there are few reports about its effect on the intestinal health and growth performance of broiler chickens. Hence, the present study was arranged to investigate the effect of dietary supplementary with EA on the intestinal barrier function and flora structure of broiler chickens challenged with Escherichia coli K88 (E. coli K88). A total of 216 healthy 1-day-old, Ross 308 broilers with uniform weight were randomly assigned into three treatment groups, six replicates in each group and twelve birds in each replicate. Broilers in the control (CTR) group and E. coli K88 infected group (ETEC) were fed with the basic diet, and 200 mg/kg EA was supplemented into the diet of the E. coli K88 infected group treated with EA (EAETEC). The animal trial had lasted for 42 days, and the outcomes showed that the ADG and ADFI during the animal trial, the jejunal villi height (VH) and the ratio of VH to crypt depth (CD) tended to be decreased with E. coli K88 treated (P< 0.05). Additionally, the level of serum diamine oxidase (DAO) and intestinal malondialdehyde (MDA) were elevated, the activity of intestinal total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px), the mRNA levels in jejunal claudin-1 and occludin were down-regulated with E. coli K88 treated as well as the transcription levels of ileal Mucin-2, aquaporin-3 (AQP-3) and Na+/H+ exchanger proteins-3 (NHE-3) (P< 0.05). In addition, E. coli K88 down-regulated the α-diversity index of cecal flora, the ratio of Bacteroidota to Firmicutes and the relative abundance of Barnesiella were up-regulated and it of Alistipes was descended with E. coli K88 treated (P< 0.05). Beyond that, the content of propionic acid in the cecal chyme was decreased and the amino acid metabolic pathways were inhibited with E. coli K88 challenged (P< 0.05). Additionally, there was a significant positive correlation between the relative abundance of Alistipes and the levels of butyric acid in the caecal chyme and the activity of GSH-Px in the intestine (P< 0.05). Interestingly, dietary supplementary with EA could reshape the intestinal flora structure and alleviate the above negative effects of E. coli K88 on broiler chickens. In conclusion, dietary supplementary with ellagic acid improved the intestinal barrier function and flora structure of broiler chickens challenged with E. coli K88.