Proteomic analysis of urinary extracellular vesicles highlights specific signatures for patients with primary aldosteronism.

Background: Urinary extracellular vesicles (uEVs) can be released by different cell types facing the urogenital tract and are involved in cellular trafficking, differentiation and survival. UEVs can be easily detected in urine and provide pathophysiological information "in vivo" without the need of a biopsy. Based on these premises, we hypothesized that uEVs proteomic profile may serve as a valuable tool in the differential characterization between Essential Hypertension (EH) and primary aldosteronism (PA). Methods: Patients with essential hypertension (EH) and PA were enrolled in the study (EH= 12, PA=24: 11 Bilateral Primary Aldosteronism subtype (BPA) and 13 Aldosterone Producing Adenoma (APA)). Clinical and biochemical parameters were available for all the subjects. UEVs were isolated from urine by ultracentrifugation and analysed by Transmission Electron Microscopy (TEM) and nanotrack particle analysis (NTA). UEVs protein content was investigated through an untargeted MS-based approach. Statistical and network analysis was performed to identify potential candidates for the identification and classification of PA. Results: MS analysis provided more than 300 protein identifications. Exosomal markers CD9 and CD63 were detected in all samples. Several molecules characterizing EH vs PA patients as well as BPA and APA subtypes were identified after statistical elaboration and filtering of the results. In particular, some key proteins involved in water reabsorption mechanisms, such as AQP1 and AQP2, were among the best candidates for discriminating EH vs PA, as well as A1AG1 (AGP1). Conclusion: Through this proteomic approach, we identified uEVs molecular indicators that can improve PA characterization and help in the gain of insights of the pathophysiological features of this disease. In particular, PA was characterized by a reduction of AQP1 and AQP2 expression as compared with EH.

Whole Exome Sequencing of Patients With Heritable and Idiopathic Pulmonary Arterial Hypertension in Central Taiwan.

Background: Genetic variants could be identified in subjects with idiopathic and heritable pulmonary arterial hypertension (PAH). The 6th World Symposium on Pulmonary Hypertension (WSPH) provided a list of genes with evidence of association with PAH. However, reports using whole exome sequencing (WES) from southeastern Asian PAH cohorts were scarce. Methods: Subjects with idiopathic and heritable PAH (N = 45) from two medical centers in central Taiwan were screened for PAH related gene variants. The genomic DNA was prepared from peripheral blood lymphocytes. We performed WES for all patients enrolled in this study. All identified gene variants were validated by polymerase-chain reaction and Sanger sequencing. The clinical and hemodynamic data were compared between bone morphogenetic protein receptor type-2 (BMPR2) gene variants carriers vs. non-carriers. Results: Eight patients (8/45 = 17.8%) was identified carrying BMPR2 gene variants and 8 patients (8/45 = 17.8%) had other WSPH-listed PAH-related gene variants (1 with ACVRL1, 1 with ENG, 1 with SMAD9, 1 with SMAD1, 1 with ATP13A3 and 3 with AQP1). In addition, a total of 14 non-WSPH-listed PAH-related genetic variant sites (ABCC8, NOTCH1, NOTCH2, NOTCH3, JAG1, BMP10, GGCX, FBLN2, ABCA3 and PTGIS) were found in this PAH cohort. Subjects carrying BMPR2 gene variant (N = 8) were younger at diagnosis of PAH (30 ± 11 vs 49 ± 13 years, p = 0.001) than the non-carrier group (N = 37). BMPR2 variant carriers had a trend toward having higher mean pulmonary arterial pressure (PAP) (61 ± 19 vs. 51 ± 13 mmHg, p = 0.076) than the non-carriers upon initial diagnosis. Pulmonary vascular resistance, right atrial pressure, cardiac output, as well as functional class were similar between BMPR2 variant carriers and non-carriers at initial diagnosis. Conclusions: We identified 17.8% of patients with BMPR2 gene variants and 17.8% subjects with other 6th WSPH-listed PAH-related gene variants in a Taiwanese idiopathic and heritable PAH cohort. PAH patients carrying BMPR2 variants presented at a younger age with a trend toward having higher mean PAP at initial diagnosis.

Hydropenia may accelerates the progression of orthotopic bladder cancer induced by N-methyl-N-nitrosourea by increasing the expression levels of AQP1, AQP3, and AQP4.

BACKGROUND: Increasing evidence has demonstrated aquaporins (AQPs) to be critical players in carcinogenesis. Here, we aimed to explore the role of hydropenia in the progression of bladder cancer (BCa), as well as to assess the expression of AQP1, AQP3, and AQP4 in bladder tissues from hydropenic and N-methyl-N-nitrosourea (MNU)-treated rats. METHODS: An orthotopic BCa model was induced by administering Sprague Dawley rats with MNU. A hydropenic rat model was established by administrating rats with 2/3 of the amount of water given to the control group. At week 8, the rats were sacrificed and their bladder tissues were collected. Then, pathological alterations in the rat bladders were assessed by hematoxylin and eosin staining. The RNA and protein expression levels of AQP1, AQP3, and AQP4 were determined by using qRT-PCR and western blot assays. RESULTS: All of the rats (100%) administrated with MNU developed tumors, of which 5 were large (diameter, 0.5-1.0 cm), 10 were medium (diameter, 0.2-0.5 cm), and 5 were small (diameter, <0.2 cm) in size. The tumors were nodular and cauliflower shaped, with multiple satellite focus, and were accompanied by bleeding, ulcers, stones, and residual urine. Hematoxylin and eosin staining revealed that the bladder mucosa was incomplete, with a large amount of necrotic tissue and obvious leukocytic infiltration. The tumor volume in the MNU + hydropenia group was significantly larger than that in the MNU group. Noticeably, hydropenia exacerbated pathological changes induced by MNU administration. QRT-PCR and western blot analysis revealed that the MNU group, hydropenia group, and MNU + hydropenia group had significantly increased levels of AQP1, AQP3, and AQP4 compared to the control group, with the most dramatic increase seen in the MNU + hydropenia group. CONCLUSIONS: Hydropenia exacerbates pathological alterations induced by MNU in rats with orthotopic BCa by increasing the expression levels of AQP1, AQP3, and AQP4. This study reveals a possible mechanism of the occurrence of BCa.

Differential Expressions of Aquaporin Subtypes in Female Reproductive Tract of Mice.

Although many aquaporin (AQP) transcripts have been demonstrated to express in the female reproductive tract, the defined localizations and functions of AQP subtype proteins remain unclear. In this study, we investigated the expression of AQP1, AQP3, AQP5, AQP6, and AQP9 proteins in female reproductive tract of mouse and characterized their precise localizations at the cellular and subcellular levels. Immunofluorescence analyses for AQP1, AQP3, AQP6, and AQP9 showed that these proteins were abundantly expressed in female reproductive tract and that intense immunoreactivities were observed in mucosa epithelial cells with a subtype-specific pattern. The most abundant aquaporin in both vagina and uterine cervix was AQP3. Each of AQP1, AQP3, AQP6, and AQP9 exhibited its distinct distribution in stratified squamous or columnar epithelial cells. AQP9 expression was predominant in oviduct and ovary. AQP1, AQP3, AQP6, and AQP9 proteins were mostly seen in apical membrane of ciliated epithelial cells of the oviduct as well as in both granulosa and theca cells of ovarian follicles. Most of AQP subtypes were also expressed in surface epithelial cells and glandular cells of endometrium in the uterus, but their expression levels were relatively lower than those observed in the vagina, uterine cervix, oviduct and ovary. This is the first study to investigate the expression and localization of 5 AQP subtype proteins simultaneously in female reproductive tract of mouse. Our results suggest that AQP subtypes work together to transport water and glycerol efficiently across the mucosa epithelia for lubrication, proliferation, energy metabolism and pH regulation in female reproductive tract.

Bumetanide-Derived Aquaporin 1 Inhibitors, AqB013 and AqB050 Inhibit Tube Formation of Endothelial Cells through Induction of Apoptosis and Impaired Migration In Vitro.

AqB013 and AqB050 compounds inhibit aquaporin 1 (AQP1), a dual water and ion channel implicated in tumour angiogenesis. We tested AqB013 and AqB050 either as monotherapy or in combination on tube formation of murine endothelial cells (2H-11 and 3B-11) and human umbilical vascular endothelial cells (HUVECs). The mechanism underlying their anti-tubulogenic effect was explored by examining cell viability, induction of apoptosis and migration using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, Annexin V/propidium iodide apoptosis assay and scratch wound assay. Tube formation of all the cell lines was inhibited by AqB013, AqB050 and the combination of the two compounds. The inhibition of 2H-11 and 3B-11 was frequently accompanied by impaired migration, whereas that of HUVEC treated with AqB050 and the combination was associated with reduced cell viability due to apoptosis. AqB013 and AqB050 exhibited an anti-tubulogenic effect through inhibition of AQP1-mediated cell migration and induction of apoptosis. Together with previously reported anti-tumour cell effect of AqB013 and AqB050, our findings support further evaluation of these compounds as potential cancer therapeutics.

Dachengqi decoction alleviates acute lung injury and inhibits inflammatory cytokines production through TLR4/NF-κB signaling pathway in vivo and in vitro.

BACKGROUND AND OBJECTIVES: Sepsis that arises from uncontrolled pulmonary inflammation could induce acute lung injury (ALI), leading to the high death rate. Dachengqi decoction (DCQD) is a common traditional Chinese herbal medicine with strong anti-inflammatory effects. The current study aimed to explore the effect of DCQD on the inflammatory cytokines production, the aquaporin-1 (AQP-1) and AQP-5 protein expression in lipopolysaccharide (LPS)-induced ALI models, and the potential mechanisms underlying its effects. METHODS: Sprague-Dawley rats and HULEC-5a cells were used as study models in the research. To detect related molecules in the study, the real-time polymerase chain reaction analysis, cell counting kit-8 assay, Western blot analysis, and enzyme-linked immunosorbent assay were performed. RESULTS: DCQD could inhibit the expression of LPS-induced inflammatory cytokines, including interleukin-6 (IL-6), IL-8, and tumor necrosis factor-α (TNF-α), in lung tissues and could reduce pulmonary edema by upregulating the expression of AQP-1 and AQP-5 in rats with LPS-induced ALI. Moreover, the results suggested that the toll-like receptor 4 (TLR4)/NF-κB signaling is indispensable for DCQD to increase the expression of AQP-1 and AQP-5 and inhibits the production of IL-6, IL-8, and TNF-α in LPS-induced HULEC-5a cells. CONCLUSION: The results of our study suggested that DCQD suppresses the TLR4/NF-κB signaling pathway, increases the protein expression of AQP-1 and AQP-5, and inhibits the production of inflammatory cytokines, by which it may alleviate the inflammatory reactions in ALI and benefit the treatments.

Reduced aquaporin-1 transcript expression in colorectal carcinoma is associated with promoter hypermethylation.

Aquaporin-1 (AQP1) is a homo-tetrameric transmembrane protein that facilitates rapid movement of water and ions across cell membranes. The clinical significance of AQP1 expression in colorectal carcinoma (CRC) is controversial. The aim of this study was to investigate the prognostic significance of AQP1 transcript expression and the association between expression and promoter methylation in normal colonic mucosa, CRC tissues and cell lines. Analysis of publicly available datasets from The Cancer Genome Atlas revealed that AQP1 expression was significantly decreased in CRC compared to normal mucosa (12.7 versus 33.3 respectively, P < 0.0001). However, expression increased with advanced disease, being significantly higher in stage IV (17.6) compared to either stage I (11.8, P = 0.0039) or II (10.9; P = 0.0023), and in patients with lymph node metastasis compared to those without (13.9 versus 11.3 respectively, P = 0.0023). Elevated expression was associated with decreased overall survival with univariate (Cox Proportional Hazard Ratio 1.60, 95% confidence interval 1.05-2.42, P = 0.028), but not multivariable analysis when considering the confounders stage and age. Analysis of HumanMethylation450 data demonstrated that AQP1 promoter methylation was significantly increased in CRC compared to normal mucosa. Analysis of CRC tissues and cell lines strongly suggested that methylation was associated with decreased expression. BRAFV600E mutation alone did not explain the increase in methylation. In conclusion, AQP1 transcript expression was decreased in CRC compared to normal mucosa, and this was associated with AQP1 promoter hypermethylation. AQP1 transcript expression increased with advanced disease but was not an independent prognostic indicator.

The Aquaporin 1 Inhibitor Bacopaside II Reduces Endothelial Cell Migration and Tubulogenesis and Induces Apoptosis.

Expression of aquaporin-1 (AQP1) in endothelial cells is critical for their migration and angiogenesis in cancer. We tested the AQP1 inhibitor, bacopaside II, derived from medicinal plant Bacopa monnieri, on endothelial cell migration and tube-formation in vitro using mouse endothelial cell lines (2H11 and 3B11) and human umbilical vein endothelial cells (HUVEC). The effect of bacopaside II on viability, apoptosis, migration and tubulogenesis was assessed by a proliferation assay, annexin-V/propidium iodide flow cytometry, the scratch wound assay and endothelial tube-formation, respectively. Cell viability was reduced significantly for 2H11 at 15 µM (p = 0.037), 3B11 at 12.5 µM (p = 0.017) and HUVEC at 10 µM (p < 0.0001). At 15 µM, the reduced viability was accompanied by an increase in apoptosis of 38%, 50% and 32% for 2H11, 3B11 and HUVEC, respectively. Bacopaside II at ≥10 µM significantly reduced migration of 2H11 (p = 0.0002) and 3B11 (p = 0.034). HUVECs were most sensitive with a significant reduction at ≥7.5 µM (p = 0.037). Tube-formation was reduced with a 15 µM dose for all cell lines and 10 µM for 3B11 (p < 0.0001). These results suggest that bacopaside II is a potential anti-angiogenic agent.

[Effects of electroacupuncture preconditioning on expression of aquaporin-1 and activity of protein kinase C in myocardium of rats with acute myocardial ischemia-reperfusion injury].

OBJECTIVE: To explore the partial action mechanism and the myocardial protective effect differences between electroacupuncture (EA) preconditioning at "Neiguan"(PC 6) and "Taiyuan"(LU 9) in rats with acute myocardial ischemia-reperfusion injury. METHODS: Ninety-six Wistar rats were randomly assigned into a sham-operation group, a model group, a Neiguan group and a Taiyuan group, 24 rats in each one. The rats in the Neiguan group and Taiyuan group were treated with EA (2 Hz in frequency, 1 mA in intensity) at "Neiguan" (PC 6) and "Taiyuan" (LU 9) respectively, 20 min per treatment, once a day for consecutive 7 days. The rats in the sham-operation group and model group were treated with immobilization for the same time, and no EA was given. The model of myocardial ischemia-reperfusion injury was established in the model group, Neiguan group and Taiyuan group 24 h after the end of EA, while the rats in the sham-operation group were treated with sham operation (no ligation was made during surgery). The myocardial ischemic size, infarction size, activity of protein kinase C (PKC) and expression of aquaporin1 (AQP1) in each group were detected. RESULTS: Compared with sham-operation group, the myocardial ischemic size, infarction size, AQP1 expression and PKC activity in the model group were significantly increased (all P<0.01); compared with the model group and Taiyuan group, the myocardial ischemic size, infarction size, PKC activity and AQP1 expression were significantly decreased in the Neiguan group (P<0.01, P<0.05). By Pearson correlation analysis, the changes of AQP1 expression were positively correlated with those of PKC activity after EA preconditioning. CONCLUSIONS: EA preconditioning at "Neiguan" (PC 6) could significantly decrease myocardial AQP1 expression and PKC activity in rats with acute myocardial ischemia-reperfusion injuing, but the effect of EA preconditioning at "Taiyuan"(LU 9) is not obvious; its protective effect is likely to be achieved by inhibiting PKC activity and AQP1 expression.

Aquaporins in Brain Edema and Neuropathological Conditions.

The aquaporin (AQP) family of water channels are a group of small, membrane-spanning proteins that are vital for the rapid transport of water across the plasma membrane. These proteins are widely expressed, from tissues such as the renal epithelium and erythrocytes to the various cells of the central nervous system. This review will elucidate the basic structure and distribution of aquaporins and discuss the role of aquaporins in various neuropathologies. AQP1 and AQP4, the two primary aquaporin molecules of the central nervous system, regulate brain water and CSF movement and contribute to cytotoxic and vasogenic edema, where they control the size of the intracellular and extracellular fluid volumes, respectively. AQP4 expression is vital to the cellular migration and angiogenesis at the heart of tumor growth; AQP4 is central to dysfunctions in glutamate metabolism, synaptogenesis, and memory consolidation; and AQP1 and AQP4 adaptations have been seen in obstructive and non-obstructive hydrocephalus and may be therapeutic targets.

The effect of ASK1 on vascular permeability and edema formation in cerebral ischemia.

Apoptosis signal-regulating kinase-1 (ASK1) is the mitogen-activated protein kinase kinase kinase (MAPKKK) and participates in the various central nervous system (CNS) signaling pathways. In cerebral ischemia, vascular permeability in the brain is an important issue because regulation failure of it results in edema formation and blood-brain barrier (BBB) disruption. To determine the role of ASK1 on vascular permeability and edema formation following cerebral ischemia, we first investigated ASK1-related gene expression using microarray analyses of ischemic brain tissue. We then measured protein levels of ASK1 and vascular endothelial growth factor (VEGF) in brain endothelial cells after hypoxia injury. We also examined protein expression of ASK1 and VEGF, edema formation, and morphological alteration through cresyl violet staining in ischemic brain tissue using ASK1-small interference RNA (ASK1-siRNA). Finally, immunohistochemistry was performed to examine VEGF and aquaporin-1 (AQP-1) expression in ischemic brain injury. Based on our findings, we propose that ASK1 is a regulating factor of vascular permeability and edema formation in cerebral ischemia.

Forensic diagnosis of ante- and postmortem burn based on aquaporin-3 gene expression in the skin.

In order to diagnose death associated with fire, it is essential to show that the person was exposed to heat while still alive. We investigated both AQP1 and AQP3 expression in the skin of an experimental burn model, as well as in forensic autopsy cases, and discuss its role in the differential diagnosis of ante- and postmortem burns. In animal experiments, there was no difference in AQP1 gene expression among four groups (n=4): antemortem burn, postmortem burn, mechanical wound, and control. However, AQP3 expression in the antemortem burn was increased significantly compared with that of the other groups even at 5min after burn. Water content of the skin was decreased significantly by the burn procedure. Consistent with animal experiments, AQP3 gene expression in the skin of antemortem burn cases was increased significantly compared with postmortem burns, mechanical wounds, and controls (n=12 in each group). These observations suggest that dermal AQP3 gene expression was increased to maintain water homeostasis in response to dehydration from burn. Finally, our results suggest that AQP3 gene expression may be useful for forensic molecular diagnosis of antemortem burn.