The increasing incidence of male infertility in humans and animals creates the need to search for new factors that significantly affect the course of reproductive processes. Therefore, the aim of this study was to determine the temporospatial expression of aquaglyceroporins (AQP3, AQP7 and AQP9) in the bovine (Bos taurus) reproductive system using immunohistochemistry and Western blotting. The study also included morphological analysis and identification of GATA-4. In brief, in immature individuals, AQP3 and AQP7 were found in gonocytes. In reproductive bulls, AQP3 was observed in spermatocytes and spermatogonia, while AQP7 was visible in all germ cells and the Sertoli cells. AQP7 and AQP9 were detected in the Leydig cells. Along the entire epididymis of reproductive bulls, aquaglyceroporins were visible, among others, in basal cells (AQP3 and AQP7), in epididymal sperm (AQP7) and in the stereocilia of the principal cells (AQP9). In males of all ages, aquaglyceroporins were identified in the principal and basal cells of the vas deferens. An increase in the expression of AQP3 in the testis and cauda epididymis and a decrease in the abundance of AQP7 in the vas deferens with age were found. In conclusion, age-related changes in the expression and/or distribution patterns of AQP3, AQP7 and AQP9 indicate the involvement of these proteins in the normal development and course of male reproductive processes in cattle.

BACKGROUND: The aim of this study was to investigate the expression of aquaporin 1 (AQP-1), AQP-3 and vascular endothelial growth factor A (VEGF-A) in peritoneal tissues of patients without kidney disease, chronic kidney disease at stages 5 (CKD 5) and patients on prolonged peritoneal dialysis with ultrafiltration failure (PDUFF), and elucidate the possible mechanism of peritoneal dialysis ultrafiltration failure.
METHODS: Peritoneal specimens were collected from the following patient groups at Xianju People\'s hospital: CKD 5, PD-UFF and normal control groups. Routine staining and immunohistochemical analyses were performed on samples obtained from the three groups.
RESULTS: The expression of AQP-1 and AQP-3 on peritoneal mesothelial cells, peritoneal vessels and in the interstitium was significantly lower in the PD-UFF group than the CKD 5 and control groups (P < .01), while no statistically significant difference was found between the CKD 5 and control groups (P > .05). In contrast, VEGF-A expression was significantly higher in peritoneal mesothelial cells, peritoneal vessels and the interstitium in the PD-UFF group than the CKD 5 and control groups (P < .01). No statistically significant difference was found between the CKD 5 and control groups (P > .05).
CONCLUSIONS: AQP-1 and AQP-3 expression levels decrease in peritoneal mesothelial cells and the vascular interstitium of patients with a prolonged peritoneal dialysis course, while VEGF-A expression gradually increases. The formation of peritoneal neovascularization and the decrease in AQP expression may be primarily associated with peritoneal dialysis ultrafiltration failure.  DOI: 10.52547/ijkd.6928.

BACKGROUND: Recently, there are a few moisturizers showing hydrating effects up to 24 hours after single application. Aquaporin 3 might be associated with the degree of skin hydration. We aimed to assess the effects of two brands of 24-hour moisturizers on the skin barrier function, as well as the AQP3 gene expression.
METHODS: Two moisturizers were applied once daily by 20 participants age 36.15 ± 9.55 years. Upper right and left forearms were randomly assigned to application of each product, whereas the right lower forearm served as control site for application of a cream base formulation. Biophysical assessments including trans epidermal water loss (TEWL), skin hydration, pH, surface lipids, and elasticity parameters were performed before intervention, 1, 4, and 24 hours after single application, following 2 weeks daily application and 1 week after termination of use. Also 5-mm punch biopsies were performed from application sites of product B and cream base formulation in for five participants after 2 weeks of application.
RESULTS: A single treatment with both products led to 24-hour increase in skin moisture in comparison with the control site (P-value <.01). Daily application of both products for 14 days also led to significant improvement in skin moisture (P-value <.01), TEWL (P-value <.01), and elasticity parameters. The increase in skin hydration was associated with upregulation of AQP3 gene expression in treated area for one of the formulations (P-value = .04).
CONCLUSIONS: The tested 24-hour moisturizers only need to be applied once daily to improve skin barrier function and hydration and up-regulate AQP3 mRNA expression.

In epithelial cells, the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-regulated Cl- channel, plays a key role in water and electrolytes secretion. A dysfunctional CFTR leads to the dehydration of the external environment of the cells and to the production of viscous mucus in the airways of cystic fibrosis patients. Here, we applied the quadriwave lateral shearing interferometry (QWLSI), a quantitative phase imaging technique based on the measurement of the light wave shift when passing through a living sample, to study water transport regulation in human airway epithelial CFBE and CHO cells expressing wild-type, G551D- and F508del-CFTR. We were able to detect phase variations during osmotic challenges and confirmed that cellular volume changes reflecting water fluxes can be detected with QWLSI. Forskolin stimulation activated a phase increase in all CFBE and CHO cell types. This phase variation was due to cellular volume decrease and intracellular refractive index increase and was completely blocked by mercury, suggesting an activation of a cAMP-dependent water efflux mediated by an endogenous aquaporin (AQP). AQP3 mRNAs, not AQP1, AQP4 and AQP5 mRNAs, were detected by RT-PCR in CFBE cells. Readdressing the F508del-CFTR protein to the cell surface with VX-809 increased the detected water efflux in CHO but not in CFBE cells. However, VX-770, a potentiator of CFTR function, failed to further increase the water flux in either G551D-CFTR or VX-809-corrected F508del-CFTR expressing cells. Our results show that QWLSI could be a suitable technique to study water transport in living cells. We identified a CFTR and cAMP-dependent, mercury-sensitive water transport in airway epithelial and CHO cells that might be due to AQP3. This water transport appears to be affected when CFTR is mutated and independent of the chloride channel function of CFTR.

Salivary gland aquaporins (AQPs) are essential for the control of saliva production and maintenance of glandular structure. However, little is known of their role in salivary gland neoplasia. Salivary gland tumors comprise a heterogeneous group of lesions, featuring variable histological characteristics and diverse clinical behaviors. Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. The aim of this study was to evaluate the expression of AQP1, AQP3, and AQP5 in 24 MEC samples by immunohistochemistry. AQP1 expression was observed in vascular endothelium throughout the tumor stroma. AQP3 was expressed in epidermoid and mucosal cells and AQP5 was expressed in mucosal cells of MEC. These proteins were expressed in the human MEC cell line UH-HMC-3A. Cellular ultrastructural aspects were analyzed by electron microscopy to certificate the tumor cell phenotype. In summary, our results show that, despite the fact that these molecules are important for salivary gland physiology, they may not play a distinct role in tumorigenesis in MEC. Additionally, the in vitro model may offer new possibilities to further investigate mechanisms of these molecules in tumor biology and their real significance in prognosis and possible target therapies.

Xeroderma is a frequent complication in diabetic patients. In this study, we investigated the mechanism underlying the onset of diabetic xeroderma, focusing on aquaporin-3 (AQP3), which plays an important role in water transport in the skin. Dermal water content in diabetic mice was significantly lower than that in control mice. The expression level of AQP3 in the skin was significantly lower in diabetic mice than in control mice. One week after streptozotocin (STZ) treatment, despite their increased blood glucose levels, mice showed no changes in the expression levels of AQP3, Bmal1, Clock, and D site-binding protein (Dbp) in the skin and 8-hydroxydeoxyguanosine (8-OHdG) in the urine. In contrast, two weeks after STZ treatment, mice showed increases in the blood glucose level, decreases in AQP3, Bmal1, Clock, and Dbp levels, and increases in the urinary levels of 8-OHdG. The results of this study suggest that skin AQP3 expression decreases in diabetes, which may limit water transport from the vessel side to the corneum side, causing dry skin. In addition, in diabetic mice, increased oxidative stress triggered decreases in the expression levels of Bmal1 and Clock in the skin, thereby inhibiting the transcription of Aqp3 by Dbp, which resulted in decreased AQP3 expression.

Human skin microbiota might play an important role in maintaining skin health and potentially prevent premature skin ageing. The use of probiotics in therapeutic skin applications is an attractive idea, as it could offer an alternative option for certain inflammatory skin disorders and dry or sensitive skin. Here, we investigated for the first time, a comparative study of live and the lysate products of probiotic strain Lactobacillus reuteri DSM 17938 in skin topical applications using ex vivo skin models focusing on anti-inflammatory and skin barrier function and in vitro assays for antimicrobial activity. Our results in ultraviolet B radiation (UVB-R)-induced inflammation model demonstrated that both live bacteria and the lysate of L. reuteri DSM 17938 reduced proinflammatory IL-6 and IL-8, illustrated in both reconstructed human epidermis (RHE) and native skin models. Live L reuteri DSM 17938 significantly increased aquaporin 3 (AQP3) gene expression, while the lysate enhanced laminin A/B levels in a healthy (unstimulated) state of RHE, suggesting a positive impact on skin barrier. In addition, live L. reuteri DSM 17938 had antimicrobial action against pathogenic skin bacteria (Staphylococcus aureus, Streptococcus pyogenes M1, Cutibacterium acnes AS12, Pseudomonas aeruginosa), whereas the lysate did not have such an effect. Therefore, it is hypothesized that L. reuteri DSM 17938 could be beneficial for general skin health, to avoid the UVB-R-mediated inflammatory cascade and/or prevent photoageing, improve barrier function or in the management of unhealthy skin prone to inflammatory conditions due to its antimicrobial, anti-inflammatory and skin barrier enhancing functions.

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Mercurial compounds are known to inhibit water permeation through aquaporins (AQPs). Although in the last years some hypotheses were proposed, the exact mechanism of inhibition is still an open question and even less is known about the inhibition of the glycerol permeation through aquaglyceroporins. Molecular dynamics (MD) simulations of human aquaporin-3 (AQP3) have been performed up to 200ns in the presence of Hg(2+) ions. For the first time, we have observed the unbiased passage of a glycerol molecule from the extracellular to cytosolic side. Moreover, the presence of Hg(2+) ions covalently bound to Cys40 leads to a collapse of the aromatic/arginine selectivity filter (ar/R SF), blocking the passage of both glycerol and water. Interestingly, the local conformational changes of the protein follow mercury coordination by water and by aminoacidic donor atoms. Overall, the obtained results are important to improve the design of selective AQP inhibitors for future therapeutic and imaging applications.

Aquaporin-3 (AQP3) is an aquaglyceroporin that plays a role in skin hydration, cell proliferation, and migration. The aim of this work was to investigate the expression of AQP3 in sun-exposed and sun-protected human skin from different age groups to understand the relationship between AQP3 and skin aging. Using standard immunohistochemical techniques, sun-exposed and sun-protected skin biopsies were taken from 60 normal individuals. AQP3 was expressed in the basal and the suprabasal layers, sparing the stratum corneum, in all specimens. Dermal expression was detected in fibroblasts, endothelial cells, and adnexa. Sun-protected skin showed a significantly higher epidermal H-score and percentage of expression (P=0.002 and <0.001, respectively) compared with sun-exposed skin. The AQP3 expression intensity showed a gradual decrease from the 20 to 35-year-old group to the 35 to 50-year-old group, with the least immunoreactivity in the above 50-year-old group. A significant difference was detected in the H-score in favor of the 20 to 35-year-old group in sun-exposed and sun-protected skin (P<0.001 for both). A significant negative correlation was noted between the AQP3 expression percentage and the age in sun-exposed (r=-0.64, P<0.001) and sun-protected skin (r=-0.53, P<0.001). In conclusion, the skin dryness observed in intrinsic and extrinsic aged skin may be explained, at least in part, by AQP3 downregulation. This may open new avenues sufficient to control skin texture and beauty. Its interaction in skin protein organization and gene polymorphism can also be tackled in future research. In addition, clinical trials using AQP3 topical applications should be carried out to evaluate its effectiveness in the reversal of age-related skin changes.