Expression Of Aquaporin Research Articles

Changes in TRPV4, AQP1, and AQP4 in a Genetic Model of Hydrocephalus Treated with a TRPV4 Antagonist

Hydrocephalus occurs as a result of cerebrospinal fluid (CSF) accumulating in the brain’s ventricles causing ventriculomegaly. Hydrocephalus can affect various cell types in the brain, and this study focuses on choroid plexus epithelial cells (CPe) and astrocytes. The choroid plexus is a tight epithelial structure within the ventricular system, responsible for producing CSF. Astrocytes are supportive cells that serve in blood‐brain barrier maintenance and brain fluid/electrolyte regulation. The CP and astrocytes contain channels and transporters that are important in regulating both CSF and brain interstitial fluid. These include transient receptor potential vanilloid 4 (TRPV4), aquaporin 1 (AQP1), and aquaporin 4 (AQP4). TRPV4 is a mechanosensitive channel and has been implicated in osmotic regulation. AQPs are a family of membrane proteins that facilitate water transport in various tissues. The CPe expresses AQP1 and TRPV4 which may be important in CSF production. Astrocytes express TRPV4 and AQP4 on their endfeet to regulate cell volume and vascular permeability. Previous studies done by the Blazer‐Yost laboratory have shown increases in AQP1, but not TRPV4 mRNA of CPe from hydrocephalic animals compared to wildtype. This study further examined changes in localization and expression of TRPV4, AQP1, and AQP4 in a rodent model of hydrocephalus.A single missense point mutation in the Transmembrane 67 (TMEM67) protein, that causes a ciliopathy resulting in hydrocephalus and polycystic kidney disease (PKD) in our rodent model, is orthologous to the human Meckel Gruber syndrome type 3 (MKS3). Treatment with the TRPV4 antagonist, RN1734, ameliorates hydrocephalus in our genetic model of hydrocephalus. Using immunohistochemical techniques, TRPV4, AQP1, and AQP4 antibodies were used to examine localization in untreated and RN1734 treated hydrocephalic animals at P15. Changes of AQP4 and TRPV4 were observed in the subventricular zone of homozygous animals. RTqPCR was used to quantitate mRNA from the CPe and subventricular region of the cortex. Preliminary RTqPCR showed increased AQP1, decreased TRPV4 and no change in AQP4 mRNA in the cortex and CPe of P15 untreated and RN1734 treated hydrocephalic animals compared to wild‐type. These data suggests that the changes occurring may be posttranslational. To observe this, Western blots were utilized to look at changes in protein. The protein expression of AQP1 and AQP4 may be increased in untreated cortical tissue from hydrocephalic animals, while total TRPV4 remaining unchanged. AQP1 and AQP4 may be still increased, while total TRPV4 decreased in animals treated with RN1734. These results provide further characterization of the role of several channels and transporters in the pathophysiology of hydrocephalus. Future studies will explore post‐translational changes in protein expression and membrane localization to compliment these studies. Examining channels and transporters can elucidate how brain fluid regulation may be altered in hydrocephalus and produce targets for pharmacological treatment in the future.

Downregulation of ten-eleven translocation-2 triggers epithelial differentiation during organogenesis

DNA methylation of cytosine bases is a major epigenetic modification that regulates gene expression and vertebrate development. The ten-eleven translocation (TET) enzymes oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), and active DNA demethylation influences gene expression specific to each developmental stage, although recent reports have shown that TET also has a non-catalytic function. In fetal mice, the epithelium in the submandibular gland (SMG) buds as a derivative of the oral cavity at embryonic day 11 (E11) and, by E15, it begins to differentiate into the salivary epithelium, which expresses water-channel aquaporin 5 (AQP5). The functional differentiation of the SMG epithelium can be regulated epigenetically, but how TET enzymes contribute is largely unknown. Here, we used several techniques, including hydroxymethylated DNA immunoprecipitation qPCR and histological analysis, to examine the changes in 5hmC levels and AQP5 and TET expression during SMG development. We found that 5hmC levels and AQP5 expression increased in the E15 SMG epithelium, while TET2 expression in the terminal buds decreased at E15. In agreement with the in vivo observations, Tet2 inhibition ex vivo led to the upregulation of AQP5 expression in terminal buds of the SMG epithelium. These results suggest that the downregulation of TET2 expression at E15 is a critical epigenetic event that establishes the epithelial fate for functional SMGs during development.

Aquaporin 1 Modulates Apoptosis Susceptibility in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) remains a fatal diagnosis despite available therapies. PAH is characterized by extensive remodeling of the pulmonary vasculature involving the formation of vaso‐occlusive lesions and a thickened medial layer of the vascular wall, both of which contain pulmonary arterial smooth muscle cells (PASMCs). We have demonstrated that PASMCs isolated from a well‐established rat model of PAH are resistant to apoptosis under both basal and stimulated conditions. The cell membrane protein aquaporin 1 (AQP1) was initially described as a water transport channel, but more recently has been implicated in other cellular functions including migration and proliferation, and in several distinct cancer types, has been associated with apoptosis resistance. AQP1 is upregulated in PASMCs isolated from rat models of PAH, although its role in apoptosis resistance is unclear. We hypothesized that increased expression of AQP1 contributes to apoptosis resistance in PASMCs.MethodsOur animal model is the Sugen‐hypoxia (SuHx) rat model of PAH in which Sugen‐5416, a vascular endothelial growth factor receptor type 2 inhibitor is injected into rats before they are placed in chronic hypoxia (10% O2) for 3 weeks, then returned to normoxia (21% O2) for 2 weeks. Control animals receive vehicle injection and are kept in normoxic (21% O2) conditions. Cells from distal pulmonary arteries are obtained via removal of the endothelium and enzymatic digestion of the tissue to obtain a pure smooth muscle population. To deplete AQP1, we transfected control and SuHx PASMCs with small interfering RNA (siRNA) directed toward either the AQP1 protein (siAQP1) or a non‐targeted sequence (siNT). Apoptosis was measured under basal conditions by Hoechst staining and visualization of DNA condensation. In complementary experiments, control PASMCs were infected with adenoviral constructs to over‐express AQP1 (AdAQP1) or green fluorescent protein (AdGFP; infection control). Cells were treated with either PBS or the apoptotic stimulus hydrogen peroxide (250 µm for 24 h). Apoptosis was again measured by Hoechst staining and visualization of DNA condensation.ResultsIn both control and SuHx PASMCs, AQP1 knock down increased apoptosis under basal conditions. In control PASMCs with increased AQP1 expression, there was no difference in apoptosis under basal conditions. To further provoke a response in these infected cells, the apoptotic stimulus hydrogen peroxide was applied; however, again there was no difference in apoptosis levels between AdAQP1 and AdGFP infected cells.ConclusionsThese data suggest that increased AQP1 may be necessary but not sufficient for apoptosis resistance. Future studies further characterizing the role of AQP1 in apoptosis resistance are necessary to understand molecular mechanisms governing resistance to apoptosis in PASMCs and provide novel pathways for new therapeutic agents targeting vascular remodeling with the potential to reverse disease.

Aquaporin 1 mediates microvascular endothelial dysfunction in the SU5416/hypoxia model of pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease, with increased pulmonary arterial pressure leading to right heart failure. The mechanisms underlying PAH are unclear, but increased pulmonary arterial smooth muscle (PASMC) and microvascular endothelial cell (MVEC) migration and proliferation leads to vaso‐occlusive lesions and vascular remodeling observed in PAH. Aquaporins regulate water transport and are expressed in many cells. We previously identified that hypoxia upregulates the expression of aquaporin 1 (AQP1) in PASMC and elevated AQP1 was required for hypoxia‐induced migration and proliferation. In this study, we wanted to elucidate whether the same is true in MVECs, and used the SU5416 plus hypoxia (SuHx) rat model, a robust model of PAH, which mimics many of the features of human PAH, to determine whether AQP1 levels were altered in MVECs and contributed to a hyperproliferative/hypermigratory phenotype.Rats were injected with the vascular endothelial growth factor receptor inhibitor, SU5416, combined with hypoxia (3 wk at 10% O2) followed by 2 wk return to normoxia. Using MVECs isolated from the normoxia (N‐MVEC) or SuHx (SuHx‐MVEC) rats, we found that AQP1 protein levels were increased in SuHx‐MVECs and associated with upregulation of AQP1 mRNA levels, even in the absence of sustained hypoxia exposure. Silencing of AQP1 reduced migration and proliferation observed in SuHx‐MVEC, whereas augmenting AQP1 levels in N‐MVECs using forced expression with an adenoviral construct containing wild‐type AQP1 (AdAQP1) was sufficient to increase cell migration (transwell assay) and proliferation (BrdU incorporation) compared to control cells infected with green fluorescent protein (AdGFP). Since we formerly reported the C‐terminal tail of AQP1 contains putative calcium and protein biding sites and is required for enhanced PASMC migration and proliferation, we tested the role of the AQP1 C‐terminal tail in N‐MVEC. Cells were treated with AdGFP, AdAQP1 or adenovirus containing AQP1 lacking the entire cytoplasmic C‐terminal tail (AdAQP1CT). In contrast to the increase in migration and proliferation induced by AdAQP1, infection with AdAQP1CT did not alter N‐MVEC migration and proliferation.Our results suggest a key role for enhanced AQP1 expression in mediating abnormal migration and proliferation in microvascular endothelial cells from a rodent model that reflects many of the features of human PAH. Interestingly, the AQP1 C‐terminal tail is required for regulating MVEC function, similar to our previous findings in PASMC.

HDAC3 Inhibition Improved Urinary Concentrating Defect in Hypokalemia by Promoting AQP2 Transcription

Hypokalemia is a common electrolyte disturbance frequently encountered in clinical medicine. Animals with hypokalemia had a significant arginine vasopressin (AVP)‐resistant polyuria with reduced expression of aquaporin 2 (AQP2) levels in the collecting ducts of the kidneys. The precise molecular mechanisms of hypokalemia‐induced nephrogenic diabetes insipidus remain unresolved. AVP induced a marked increase in histone H3K27 acetylation (H3K27ac) across the body of the AQP2 gene, in the promoter and in upstream of the AQP2 transcriptional start site in mouse mpkCCD cell line (PMID: 29572403). The purpose of the present study was to investigate whether enhanced histone acetylation prevented decreased AQP2 expression and improved urinary concentrating defect in rats with hypokalemia. Male Wistar rats were fed potassium‐free diet with or without 4‐phenylbutyric acid (4‐PBA) or a selective inhibitor of histone deacetylase 3 (HDAC3) RGFP966 for 4 days. 4‐PBA or RGFP966 markedly increased AQP2 mRNA and protein levels in kidney inner medulla of rats with hypokalemia, which was associated with decreased urine output and increased urinary osmolality. Protein expression of H3K27ac was markedly decreased in kidney inner medulla of hypokalemic rats, which was significantly prevented by 4‐PBA or RGFP966. Expression of H3K27ac was decreased in primary cultured inner medullary collecting duct cells (IMCD) or mpkCCD cells cultured in potassium‐deprivation media, in particular, H3K27ac in the promoter region of AQP2 was markedly decreased, which was associated with reduced mRNA levels of AQP2. Protein expression of HDAC3 was significantly upregulated in both mpkCCD and IMCD cells in response to potassium deprivation; the binding of HDAC3 to the promoter of AQP2 was also dramatically increased. RGFP966 significantly increased expression of H3K27ac and AQP2 protein and enhanced the binding of H3K27ac to AQP2 in mpkCCD cells. In conclusion, HDAC3 inhibition prevented downregulation of AQP2 and improved urinary concentrating defect induced by potassium deprivation, likely through enhancing acetylation of H3K27 and transcription of AQP2.

The Correlation between the Increased Expression of Aquaporins on the Inner Limiting Membrane and the Occurrence of Diabetic Macular Edema.

Purpose Diabetic macular edema (DME) is a major cause of vision loss in patients with diabetic retinopathy; this study is aimed at comparing the expression of aquaporins (AQPs) on the inner limiting membranes (ILMs) of various vitreoretinal diseases and investigating the role of aquaporins expressed on the ILMs in mediating the occurrence of DME. Methods The whole-mounted ILM specimens surgically excised from patients with various vitreoretinal diseases (idiopathic macular hole, myopic traction maculopathy, and diabetic retinopathy) were analyzed by immunohistochemistry (IHC). The distribution and morphology of AQP4, AQP7, and AQP11 on the ILMs were correlated with immunohistochemical staining characteristics. Moreover, immunofluorescence of AQP4 was performed on the ILM specimens of the patient in four groups: the control group, negative control group, no DME group, and DME group. The immunofluorescence intensity value of AQP4 was measured using ImageJ. The difference between the four groups and the correction between the immunofluorescence value and central foveal thickness (CFT) were analyzed. Results In IHC sections, the expression of AQP4, AQP7, and AQP11 on ILMs of diabetic retinopathy (DR) with macular edema, respectively, seemed to be more abundant than in the idiopathic macular hole (iMH) and myopic traction maculopathy (MTM). Moreover, markedly higher fluorescence intensity of AQP4 of ILMs was determined in the DME group (51.05 ± 5.67) versus the other three groups (P < 0.001). A marked positive association was identified between the fluorescence intensity of AQP4 and CFT (r = 0.758; P = 0.011). Conclusions AQP4, AQP7, and AQP11 can be expressed on human ILM in vivo. The increased expression of AQPs on the ILMs of DR may be associated with the occurrence of DME. Moreover, the degree of DME may be positively correlated with the expression of AQP4 on the ILMs.

Rhabdomyolysis, myoglobinuric nephrosis, and crystalline nephropathy in a captive bottlenose dolphin.

A 5-y-old female bottlenose dolphin (Tursiops truncatus) from an aquarium in Japan had clinical signs of anorexia, vomiting, and bradykinesia. Enrofloxacin and lactated Ringer solution were administered for treatment of bacterial infection and for rehydration. Elevations of creatine kinase and aspartate aminotransferase activities were detected on day 4 of treatment, indicating that rhabdomyolysis had developed on day 3. On day 5, serum creatinine and urea concentrations increased and remained high throughout the remaining treatment; the dolphin died on day 16. Postmortem examination revealed massive necrosis of the longissimus dorsi muscles. Histologic examination revealed extensive necrosis of skeletal myofibers, multifocal renal tubular necrosis with intratubular casts and crystals, and suppurative bronchopneumonia. The renal casts labeled positively with anti-myoglobin antibody; expression of aquaporin-1 was decreased in renal tubules compared to normal kidney tissue. To our knowledge, this description of clinicopathologic findings of rhabdomyolysis leading to acute kidney injury with concomitant crystalline nephropathy has not been reported previously in a bottlenose dolphin.

Gandan Oral Liquid Improves Exudative Pneumonia by Upregulating Bacteria Clearance via Regulating AQP5 and MUC5AC in Rats

Gandan oral liquid (GOL) is a mixture of crude extracts from licorice and Radix isatidis. Clinically, it has been widely used in the treatment of exudative pneumonia (EP) in animals. But the molecular mechanism of these effects is unclear. Therefore, antibacterial activity and therapeutic effect were tested in vitro and in vivo. Exudative pneumonia was established with the intraperitoneal injection of LPS, followed by continuous intranasal inoculation of Klebsiella pneumoniae (KP). After that, Gandan oral liquid, acetylcysteine, and levofloxacin were given through the intragastric route for five days, and clinical symptoms were observed and counted. The bacterial content of alveolar lavage fluid was determined, hematology analysis was performed, and lung histology examination was performed. Western blotting, immunohistochemistry, and immunofluorescence were used to detect the expression levels of AQP3, AQP5, and MUC5AC in lung tissues. ELISA kit was used to detect serum and BALF cytokines levels. The results showed that GOL (242 mg/mL) had no antibacterial activity on Klebsiella pneumonia (KP), and the effect was significantly worse than levofloxacin. However, the therapeutic test in vivo of the rat model of bacterial EP showed different results. After treatment, GOL administration ameliorated EP and increased the expression of mucoprotein -5AC (MUC5AC), and GOL promoted water secretion of the respiratory tract by increasing the expression of aquaporin-5 (AQP5) and decreasing the levels of proinflammatory cytokines (TNF-α, IL-6, and IL-1β). Conclusion. GOL accelerates the water secretion of respiratory tract, inhibits the inflammatory response, induces removal of bacteria of respiratory tract via the AQPs/MUC pathway, and ultimately ameliorates EP.

Effects of C5a and Receptor CD88 on Glutamate and N-Methyl-D-Aspartic Acid Receptor Expression in the Mouse Model of Optic Neuromyelitis

Objective To analyze the role of C5a, C5a receptor (CD88), glutamic acid, and N-methyl-D-aspartic acid receptors (NMDAR1 and NMDAR2B) in the onset of neuromyelitis optica (NMO) disease in mice. Method To select C57BL/6 wild-type (WT) mice and C5a receptor gene knockout (C5aR-/-) mice, use NMO-IgG and hemolytic complement to intervene in spinal cord tissue sections and optic nerves to establish an NMO model in vitro. The experiment was carried out with five groups (control group, WT group, C5aR-/- group, C5a group, and C5a+C5aRA group), with six mice in each group. The differences of American spinal cord injury (ASIA) motor scores were compared among all groups. The expressions of aquaporin (AQP4), glial fibrillary acidic protein (GFAP), NMDAR1, and NMDAR2B in spinal cord and optic nerve tissues were detected. The difference of glutamic acid (Glu) concentrations in culture solutions of the spinal cord and optic nerves was compared. Result The ASIA motor score of the control group was significantly lower than that of the other four groups. The C5a-/- group was significantly higher than the WT group. The C5a+C5aRA group was significantly higher than the C5a group in terms of ASIA motor score. In the control group, AQP4 and GFAP showed expression loss. The C5aR-/- group's loss rate was significantly higher than that of the WT group. The loss rate of the C5a+C5aRA group was significantly higher than that of the C5a group. In the control group, the protein expressions of NMDAR1 and NMDAR2B were significantly lower than that of the other four groups. The C5aR-/- group was significantly higher than the WT group. The C5a+C5aRA group was significantly higher than the C5a group in protein expression. In the control group, the concentration of Glu in the C5aR-/- group was significantly higher than that in the WT group, and the C5a group was significantly lower than the C5a+C5aRA group. Conclusion The deletion of the C5a receptor promotes NMDAR activity, which affects the toxic excitatory effect of NMDAR in NMO and regulates the neurotoxic effect of glutamic acid, thus participating in the pathogenesis of NMO.

Cholecystokinin promotes functional expression of the aquaglycerol channel aquaporin 7 in adipocytes.

Cholecystokinin (CCK) promotes triglyceride storage and adiponectin production in white adipose tissue (WAT), suggesting that CCK modulates WAT homeostasis. Our goal was to investigate the role of CCK in regulating the expression and function of the aquaglycerol channel aquaporin 7 (AQP7), a protein that is pivotal for maintaining adipocyte homeostasis and preserving insulin responsiveness. The effect of the bioactive fragment of CCK, CCK-8, in regulating adipose AQP7 expression and glycerol efflux was assessed in rats as well as in preadipocytes. Moreover, the involvement of insulin receptors in the effects of CCK-8 was characterized in preadipocytes lacking insulin receptors. CCK-8 induced AQP7 gene expression in rat WAT, concomitantly increasing plasma glycerol concentration. In isolated preadipocytes, CCK-8 also enhanced both AQP7 expression and glycerol leakage. The effects of CCK-8 were independent of the lipolysis rate, as CCK-8 failed to promote fatty acid release by adipocytes. In addition, CCK-8 did not enhance hormone sensitive lipase phosphorylation, which is the rate-limiting step of lipolysis. Moreover, the effects of CCK-8 were dependent on the activation of protein kinase B and PPARγ. Silencing insulin receptor expression inhibited CCK-8-induced Aqp7 expression in preadipocytes. Furthermore, insulin enhanced the effect of CCK-8. CCK regulates AQP7 expression and function, and this effect is dependent on insulin. Accordingly, CCK receptor agonists could be suitable for preserving and improving insulin responsiveness in WAT.

Comparative study on the expression profile of Aquaporin5 (AQP5) gene in skinfibroblast cells of native goats enabling their water utilization efficiency

Lack of availability of good quality and quantity of water affects the physiology of goats. Goats may adapt to thrive well in water deficit areas by making alterations in the expressions of aquaporin (AQP) genes for their efficient water use. The present study was carried out in skin fibroblast cells of Barbari and Sirohi goats. Under in vitro conditions, during different temperatures and osmotic treatments, variations in relative expression of AQP3 genes were observed. At higher temperatures the relative expression of AQP3 genes in Sirohi breed was found to be significantly higher (p&lt;0.01) than Barbari breed. However, during hyperosmotic concentrations at normal temperatures the relative expression of AQP3 mRNA was significantly ((p&lt;0.05) increased in both the breeds. During a high temperature combination with hyperosmotic concentration in cell culture of skin fibroblast cell the relative expression of AQP3 mRNA was increased in Sirohi breed (p&lt;0.01) whereas it decreased in Barbari goat’s breed. The variations in AQP3 gene expression during water stress condition and during hyperosmotic concentrations of skin fibroblasts cell culture suggests the positive involvement of AQP3 gene in maintaining the water balance in the body.

The Effect and Mechanism of New Processing Method of Codonopsis pilosula on Endocrine Physique Index in Rats.

Objective To explore the effect and mechanism of a new processing method of Codonopsis pilosula (CP) on the endocrine physique index in rats. Methods The rats were randomly assigned into the control group, model group, CP group (3.75 g/kg crude drug), rice-fried CP group (3.75 g/kg crude drug), and honey-roasted CP group (3.75 g/kg), with 10 rats in each group. All rats were gavaged according to the body weight of 1 mL/100 g every morning for 3 weeks. The water extracts of different processed products of CP were given to the drug group, the blank group, and the model group which were given the same volume of normal saline during the experiment. The model group and each administration group were fed every other day and drank freely for 21 days, during which the weight was weighed every 2 days. The changes of the organ index; the contents of cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), adrenocorticotropic hormone (ACTH), and cortisol (Cor); and the activity of sodium and potassium adenosine triphosphate (Na+K+-ATP) were measured by enzyme-linked immunosorbent assay (ELISA). The expression of aquaporin-1 (AQP1) and aquaporin-2 (AQP2) mRNA was detected by RT-PCR. Results Effect on the organ index: the organ index of the control group, CP group, rice-fried group, and honey moxibustion group was higher compared to that of the model group, and the organ index of the honey moxibustion group was the highest (P < 0.05). The level of cAMP and the ratio of cAMP/cGMP in the model group were significantly higher compared to those of the control group (P < 0.05); CGMP in the model group decreased significantly (P < 0.05). Compared with the model group, the level of cAMP in the CP group, rice-fried group, and honey moxibustion group decreased significantly, while the ratio of cGMP and cAMP/cGMP increased significantly (P < 0.05). Compared with the CP group, rice-fried group, and honey moxibustion group, the level of cAMP and the ratio of cAMP/cGMP in the honey moxibustion group were lower compared to those in the other two groups, and the ratio of cGMP in the honey moxibustion group was higher compared to that in the other two groups (P < 0.05). The contents of ACTH and Cor in the model group were significantly higher compared to those in the control group (P < 0.05). Compared with the model group, the contents of ACTH and Cor in the CP group, rice-fried group, and honey moxibustion group were significantly lower compared to those in the model group (P < 0.05). Compared with the CP group, rice-fried group, and honey moxibustion group, the contents of ACTH and Cor in the honey moxibustion group were higher compared to those in the other two groups (P < 0.05). The content of the Na+K+-ATP enzyme in the model group was significantly higher compared to that in the control group (P < 0.05). Compared with the model group, the content of the Na+K+-ATP enzyme in the CP group, rice-fried group, and honey moxibustion group decreased significantly (P < 0.05). Compared with the CP group, rice-fried group, and honey moxibustion group, the content of the Na+K+-ATP enzyme in the honey moxibustion group was higher compared to that in the other two groups (P < 0.05). The expression of AQP1 and AQP2 mRNA in the kidney tissue of the kidney yin deficiency model group was significantly higher compared to that of the control group (P < 0 05). Compared with the model group, the expression levels of AQP1 and AQP2 mRNA in the renal tissue of rats in the CP group, rice-fried group, and honey moxibustion group decreased in different degrees (P < 0.05). There was no statistical difference between the CP group, rice stir-frying group, and honey moxibustion group. Conclusion This study proves that the new processing method of CP can improve the endocrine physique index of rats, enhance their organ quality, and regulate the disorder of water metabolism in kidney yin deficiency syndrome and has a certain therapeutic effect on kidney yin deficiency syndrome. Different new processing methods of CP have different effects on promoting endocrine physique indexes of rats. It is concluded that honey-roasted CP has the best effect on promoting spleen deficiency, which may be through glucose metabolism, amino acid metabolism, and nucleotide metabolism, increasing ATP energy metabolism, so as to strengthen the symptoms of spleen deficiency in rats. The experimental data of this study indicate that the effect of honey-roasted CP is better compared to that of other processed products, which provides an experimental basis for the rational clinical application of the new processed products.

Human Norovirus Induces Aquaporin 1 Production by Activating NF-κB Signaling Pathway.

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

Effects of Sphingomyelin-Containing Milk Phospholipids on Skin Hydration in UVB-Exposed Hairless Mice.

Reactive oxygen species (ROS) generated by ultraviolet (UV) exposure cause skin barrier dysfunction, which leads to dry skin. In this study, the skin moisturizing effect of sphingomyelin-containing milk phospholipids in UV-induced hairless mice was evaluated. Hairless mice were irradiated with UVB for eight weeks, and milk phospholipids (50, 100, and 150 mg/kg) were administered daily. Milk phospholipids suppressed UV-induced increase in erythema and skin thickness, decreased transepidermal water loss, and increased skin moisture. Milk phospholipids increased the expression of filaggrin, involucrin, and aquaporin3 (AQP3), which are skin moisture-related factors. Additionally, hyaluronic acid (HA) content in the skin tissue was maintained by regulating the expression of HA synthesis- and degradation-related enzymes. Milk phospholipids alleviated UV-induced decrease in the expression of the antioxidant enzymes superoxidase dismutase1 and 2, catalase, and glutathione peroxidase1. Moreover, ROS levels were reduced by regulating heme oxygenase-1 (HO-1), an ROS regulator, through milk phospholipid-mediated activation of nuclear factor erythroid-2-related factor 2 (Nrf2). Collectively, sphingomyelin-containing milk phospholipids contributed to moisturizing the skin by maintaining HA content and reducing ROS levels in UVB-irradiated hairless mice, thereby, minimizing damage to the skin barrier caused by photoaging.

Overexpression of Aquaporin-3 Alleviates Hyperosmolarity-Induced Nucleus Pulposus Cell Apoptosis via Regulating the ERK1/2 Pathway.

Intervertebral disc degeneration (IDD) is closely related to osmolarity, which fluctuates with daily activities, and hyperosmolarity may be a contributor to nucleus pulposus (NP) cells apoptosis. Aquaporin-3 (AQP-3) belongs to the family of aquaporins and mainly transports water and other small molecular proteins, which is reduced with the aging of the intervertebral disc. ERK1/2 pathway is one type of mitogen-activated protein kinase (MAPK) and is associated with cellular apoptosis. This study was aimed to investigate the effects of AQP-3 on NP cells apoptosis induced by a hyperosmolarity and focused on the role of the ERK1/2 signaling pathway. We found that NP apoptosis could be induced by hyperosmolarity (550 mOsm/kg), and downregulation of AQP-3 and inhibition of ERK1/2 could be simultaneously observed. Therefore, lentivirus was used to enhance the expression of AQP-3 to compare apoptosis between AQP-3-overexpressed NP cells and the control NP cells. The results showed that apoptosis could be alleviated by overexpression of AQP-3 and the activity of ERK1/2 could also be promoted. Furthermore, we found that the inhibitor U0126 could partly aggravate apoptosis of the AQP-3-overexpressed NP cells. In summary, our results suggested that overexpression of AQP-3 could protect against hyperosmolarity-induced NP cell apoptosis via promoting the activity of the ERK1/2 pathway. This study may shed light on a better understanding of the pathologic mechanism of IDD and bring AQP-3 into the therapeutic approaches for IDD treatment.

Low-dose aspirin prevents LPS-induced preeclampsia-like phenotype via AQP-1 and the MAPK/ERK 1/2 pathway.

Clinical studies suggest that early pregnancy is the critical window for the prevention of preeclampsia by low-dose aspirin (LDA). Abnormal extravillous trophoblast (EVT) cell invasion and spiral artery remodeling during early placentation have been observed in preeclampsia cases. Thus, we hypothesized LDA prevents preeclampsia by mitigating EVT migration/invasion and spiral artery remodeling dysfunction. A single systemic lipopolysaccharide (LPS) (1μg/kg) injection was administrated in pregnant mice at e14.5 to induce a preeclampsia-like pregnant mouse model. We administered LDA (2.5μg/g body weight/day) and observed the effects on LPS-induced preeclampsia-like symptoms by examining the placental histology, protein expression, EVT invasion, and spiral artery remodeling. In human EVT cell line, HTR-8/SVneo, we investigated cell invasion and migration by matrigel and wound healing assays, respectively. Signaling pathways were surveyed using inhibitors, siRNA transfections, and Western blot. LDA treatment significantly reversed the preeclampsia-like phenotype induced by LPS, as observed by decreases in hypertension, proteinuria, and fetal growth retardation. The numbers of pathological lesions, including excessive extracellular matrix deposition, endotheliosis, and collapsed glomerular capillaries in kidneys, were significantly lower in the LDA+LPS vs. the LPS group. LDA pretreatment eliminated placental lesions, including calcification, edema, and narrowed uterine spiral arteries and reduced aquaporin-1 (AQP-1) protein expression. In HTR-8/SVneo cells, LDA rescued the decreased cell migration and invasion induced by LPS. The phosphorylation of ERK1/2 was up-regulated and AQP-1 expression was decreased by LPS, which were reversed by LDA treatments. The effects of LDA were inhibited when AQP-1 expression was downregulated by siRNA transfection. This study provides new evidence that supports the use of LDA for the prevention of preeclampsia and suggests that the effects of LDA are mediated through a novel mechanism of a water channel, AQP-1, and MAPK/ERK 1/2 signaling.

Network pharmacological prediction and molecular docking analysis of the combination of Atractylodes macrocephala Koidz. and Paeonia lactiflora Pall. in the treatment of functional constipation and its verification.

BackgroundWe aimed to reveal the mechanism of functional constipation in the treatment of Atractylodes macrocephala Koidz. (AMK) and Paeonia lactiflora Pall. (PLP).MethodsThe main active ingredients of AMK and PLP were screened by the Traditional Chinese Medicine Systems Pharmacology (TCMSP) platform. A database of functional constipation targets was established by GeneCard and OMIM. An “ingredient‐target” network map was constructed with Cytoscape software (version 3.7.1), and molecular docking analysis was performed on the components and genes with the highest scores. The rats in the normal group were given saline, and those in the other groups were given 10 mg/kg diphenoxylate once a day for 14 days. The serum and intestinal tissue levels of adenosine monophosphate (cAMP), protein kinase A (PKA), and adenylyl cyclase (AC) of the rats and aquaporin (AQP)1, AQP3, and AQP8 were measured.ResultsAMK and PLP had a significant role in the regulation of targets in the treatment of functional constipation. After treatment with AMK, PLP, or mosapride, the serum and intestinal tissue levels of AC, cAMP, and PKA were significantly downregulated. Groups receiving AMK and PLP or mosapride exhibited a reduction in the level of AQP1, AQP3, and AQP8 to varying degrees.ConclusionMolecular docking analysis revealed that AMK and PLP had a significant role in the regulation of targets in the treatment of functional constipation. Studies have confirmed that AMK and PLP can also affect AC, cAMP, and PKA. AC, cAMP, and PKA in model rats were significantly downregulated. AQP expression is closely related to AC, cAMP, and PKA. AMK and PLP can reduce the expression of AQP1, AQP3, and AQP9 in the colon of constipated rats.

Cellular Distribution of Brain Aquaporins and Their Contribution to Cerebrospinal Fluid Homeostasis and Hydrocephalus.

Brain aquaporins facilitate the movement of water between the four water compartments: blood, cerebrospinal fluid, interstitial fluid, and intracellular fluid. This work analyzes the expression of the four most abundant aquaporins (AQPs) (AQP1, AQP4, AQP9, and AQP11) in the brains of mice and discuss their contribution to hydrocephalus. We analyzed available data from single-cell RNA sequencing of the central nervous system of mice to describe the expression of aquaporins and compare their distribution with that based on qPCR, western blot, and immunohistochemistry assays. Expression of AQP1 in the apical cell membrane of choroid plexus epithelial cells and of AQP4 in ependymal cells, glia limitans, and astrocyte processes in the pericapillary end foot is consistent with the involvement of both proteins in cerebrospinal fluid homeostasis. The expression of both aquaporins compensates for experimentally induced hydrocephalus in the animals. Recent data demonstrate that hypoxia in aged animals alters AQP4 expression in the choroidal plexus and cortex, increasing the ventricle size and intraventricular pressure. Cerebral distensibility is reduced in parallel with a reduction in cerebrospinal fluid drainage and cognitive deterioration. We propose that aged mice chronically exposed to hypoxia represent an excellent experimental model for studying the pathophysiological characteristics of idiopathic normal pressure hydrocephalus and roles for AQPs in such disease.

Qi Sui Zhu Shui Plaster Inhibits AQP1 and MAPK Signaling Reduces Liver Damage Induced by Cirrhotic Ascites

Objective At present, there is no special treatment for cirrhotic ascites in modern medicine. Qi Sui Zhu Shui plaster (QSZSP) has been used in ascites. The purpose of this study was to investigate the mechanism of action of QSZSP in the treatment of cirrhotic ascites and its relationship with aquaporin 1 (AQP1). Methods Twenty-four rats were divided into four groups, six rats in each group. Carbon tetrachloride-olive oil is injected into modeling. The control and model groups are treated with blank gel plaster (2 cm × 2 cm), QSZSP low-dose group is treated with Qi Sui Zhu Shui plaster (1 cm × 1 cm), and QSZSP high-dose group is treated with Qi Sui Zhu Shui plaster (2 cm × 2 cm). The changes in body weight and abdominal circumference were measured, the histopathological changes in liver, kidney, and peritoneum were observed in HE staining, the biochemical indexes related to liver function were detected, and the changes in AQP1 expression and the activation of MAPK pathway in the liver, kidney, and peritoneal tissues were evaluated in IHC staining and Western blot. Results After one week of injection of carbon tetrachloride-olive oil, the rats in the model group increased their body weight slowly, the abdominal circumference of the model rats continued to increase with time. After 16 weeks of construction of the cirrhotic ascites model, the liver, kidney, and peritoneum were significantly damaged, and the serum levels of TBiL, AST, ALT, Cr, BUN, K, Na, and Ca in the rats were significantly higher (P < 0.001) and ALB levels were significantly lower (P < 0.001) than those in the control group. After 4 weeks of treatment, the liver, kidney, and peritoneal injury were improved. TBiL, AST, ALT, Cr, BUN, K, Na, and Ca levels were significantly lower (P < 0.001) and ALB levels were significantly higher (P < 0.001) than those in the model group. The protein expression of AQP1, p-ERK, p-JNK, and p-p38 was found to be inhibited in the liver, kidney, and peritoneum. Conclusion QSZSP inhibits the protein expression of AQP1 and MAPK signaling pathway in the liver, peritoneum, and kidney to alleviate liver, kidney, and peritoneal injury caused by cirrhotic ascites, thus reducing the abnormal growth of abdominal circumference.

Oxidative Stress-Induced Alterations of Cellular Localization and Expression of Aquaporin 1 Lead to Defected Water Transport upon Peritoneal Fibrosis.

Being one of the renal replacement therapies, peritoneal dialysis (PD) maintains around 15% of end-stage kidney disease patients’ lives; however, complications such as peritoneal fibrosis and ultrafiltration failure during long-term PD compromise its application. Previously, we established a sodium hypochlorite (NaClO)-induced peritoneal fibrosis porcine model, which helped to bridge the rodent model toward pre-clinical human peritoneal fibrosis research. In this study, the peritoneal equilibration test (PET) was established to evaluate instant functional changes in the peritoneum in the pig model. Similar to observations from long-term PD patients, increasing small solutes transport and loss of sodium sieving were observed. Mechanistic investigation from both in vivo and in vitro data suggested that disruption of cytoskeleton induced by excessive reactive oxygen species defected intracellular transport of aquaporin 1, this likely resulted in the disappearance of sodium sieving upon PET. Functional interference of aquaporin 1 on free water transport would result in PD failure in patients.