Different expressions of aquaporin water channels and macrophages infiltration in human cervix remodeling during pregnancy.

Despite aquaporin water channels (AQPs) play a critical role in maintaining water homeostasis in female reproductive tract and prompt a gradual increase in water content in cervical edema as pregnancy progressed, their relationship with macrophage infiltration and collagen content in human cervical remodeling need to be further investigated. This is the first study to examine the expression and localization of AQP3, AQP4, AQP5, AQP8, and macrophages simultaneously in human cervical ripening. The immunoreactivity of these AQPs was 2.6 to 6-fold higher on gestational weeks 26 (GD26W) than that on GD6W and GD15W, but AQP4 expression on GD39W dropped a similar extent on GD15W, other AQPs continued to rise on GD39W. The AQP3, AQP4, and AQP5 intensity seemed more abundant in cervical stroma than in the perivascular area on GD26W; the distribution of AQP3, AQP5, and AQP8 in cervical stroma was equivalent to that in the perivascular area on GD39W. Macrophage numbers were 1.7-fold higher in subepithelium region and 3.0-fold higher in center area on GD26W than that on GD15W; such numbers remained elevated on GD39W. The electron micrographs showed that cervical extensibility increased significantly on GD26W and GD39W accompanied with increased macrophage infiltration, cervical water content, and much more space among collagen fibers. These findings suggest that the upregulation of AQPs expression in human cervix is closely related to enhanced macrophage infiltration during pregnancy; there may be a positive feedback mechanism between them to lead the increase of water content and the degradation of collagen.

Altered mucins and aquaporins indicate dry eye outcome in patients undergoing Vitreo-retinal surgery.

Vitreo-retinal (VR) surgeries induce conjunctival changes. However, there are no study reports regarding prevalence and severity of dry eye after these surgeries. This study evaluated dry eye outcome after VR surgery. Patients undergoing VR surgery classified as scleral buckle and microincision vitrectomy surgery (n = 44, mean age: 56.09±10.2 years) were recruited. Dry eye evaluation was done before and 8 weeks after surgery (2 weeks after omitting topical eye drops). Conjunctival imprint cytology for goblet cell count and tear Mucin 5AC (MUC5AC) protein estimation was done. Gene expressions of MUC5AC, MUC4, MUC16, Aquaporin 4 (AQP4) and AQP5 were analyzed in the conjunctival imprint cells by qPCR. None of the patients exhibited clinical signs of dry eye after VR surgery. But the conjunctival goblet cell density (GCD) was significantly lowered post-VR surgery (63% cases, **p = 0.012) with no alterations in the tear MUC5AC protein. Post-VR surgery, the conjunctival cell gene expression of MUC4, MUC16 and AQP4 were significantly increased (*p = 0.025, *p = 0.05 and *p = 0.02 respectively) and AQP5 was significantly lowered (*p = 0.037), with no change in MUC5AC expression. Tear cytokines were significantly increased post-VR surgery (anti-inflammatory: IL1RA, IL4, IL5, IL9, FGF; PDGFbb and pro-inflammatory: IL2, IL6, IL15, GMCSF and IFNg). Though clinical signs of dry eye were not observed after VR surgery, ocular surface changes in the form of reduced GCD, altered MUC5AC, MUC4, MUC16, AQP4, AQP5 and cytokines are suggestive of dry eye outcome at the molecular level especially inpatients aged above 51 years, especially female gender and those who are diabetic.

Thyroid Function Modulates Lung Fluid and Alveolar Viscoelasticity in Mechanically Ventilated Rat.

BACKGROUND: Mechanical ventilation (MV) is life saving; yet it may induce severe lung injury and lead to multisystem organ failure and death. Thyroid hormones (THs) promote alveolar fluid clearance and alleviates hypoxia-induced lung injury. Given that the mechanism involved in hypoxia-induced lung injury is different from that of ventilator-induced lung injury, we examined the effects of thyroid function on lung extravascular fluid (LF), aquaporin 5 (AQP 5) expression, and alveolar viscoelasticity (AVE) in mechanically ventilated rat. METHODS: Hypothyroid (hypo) and hyperthyroid (hyper) animals were generated by administration of metimazole and L-thyroxine, respectively. Lung injury was induced by high-tidal volume MV. The LF was estimated by lung wet weight-to-dry weight ratio assessment. Expression of AQP 5 was evaluated by western blotting and in situ immunohistochemistry. The AVE was judged by elastic lung pressure/volume curve recording. RESULTS: Injurious MV significantly reduced lung AQP 5 expression and altered LF and AVE in a thyroid function-dependent manner. Regardless of animals' ventilation mode, hyper state caused significant reductions in LF and lung AQP 5 protein. It also improved AVE irrespective of animals' ventilation mode. The effects of hypo condition on LF, AQP 5 expression, and AVE were in contrast to that of hyper state. CONCLUSIONS: These data indicate that thyroid function has profound effects on LF, AQP 5, and AVE in mechanically ventilated lungs. Given that the effects of thyroidal status were as prominent as that of injurious MV, we suggest that thyroid function should be considered when patients are to be subjected to MV.

Dynamics of Salivary Gland AQP5 under Normal and Pathologic Conditions.

AQP5 plays an important role in the salivary gland function. The mRNA and protein for aquaporin 5 (AQP5) are expressed in the acini from embryonic days E13-16 and E17-18, respectively and for entire postnatal days. Ligation-reopening of main excretory duct induces changes in the AQP5 level which would give an insight for mechanism of regeneration/self-duplication of acinar cells. The AQP5 level in the submandibular gland (SMG) decreases by chorda tympani denervation (CTD) via activation autophagosome, suggesting that its level in the SMG under normal condition is maintained by parasympathetic nerve. Isoproterenol (IPR), a ß-adrenergic agonist, raised the levels of membrane AQP5 protein and its mRNA in the parotid gland (PG), suggesting coupling of the AQP5 dynamic and amylase secretion-restoration cycle. In the PG, lipopolysaccharide (LPS) is shown to activate mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signalings and potentially downregulate AQP5 expression via cross coupling of activator protein-1 (AP-1) and NF-κB. In most species, Ser-156 and Thr-259 of AQP5 are experimentally phosphorylated, which is enhanced by cAMP analogues and forskolin. cAMP-dependent phosphorylation of AQP5 does not seem to be markedly involved in regulation of its intracellular trafficking but seems to play a role in its constitutive expression and lateral diffusion in the cell membrane. Additionally, Ser-156 phosphorylation may be important for cancer development.

Immunohistochemical expression of P-selectin, SP-A, HSP70, aquaporin 5, and fibronectin in saltwater drowning and freshwater drowning.

The diagnosis of drowning is one of the most difficult in forensic medicine. The aim of this study was to analyze pulmonary tissue reactions in death by drowning. In particular, we focused on the immunohistochemical expression of P-selectin, SP-A, HSP70, AQP-5, and fibronectin to investigate our expression in drowning and to understand whether there are differences between saltwater drowning (SWD) and freshwater drowning (FWD), which may indicate a different pathophysiology. We retrospectively investigated 10 cases of SWD (Mediterranean Sea) from the Institute of Legal Medicine of Genoa (Italy), and 10 cases of FWD (Lake of Geneva) from the University Center of Legal Medicine of Geneva (Switzerland). As control group, we examined 10 cases of death by acute external bleeding, characterized by minimal respiratory distress. As compared with controls, in SWD cases, the results showed a decrease of SP-A expression with membrane patterns. Furthermore, we observed a greater SP-A expression with granular pattern in drowning cases without statistically significant difference between SWD and FWD. For the markers AQP-5, HSP70, fibronectin, and P-selectin, no statistically significant differences were found between SWD, FWD, and controls.

Submandibular gland-specific inflammaging-induced hyposalivation in the male senescence-accelerated mouse prone -1 line (SAM-P1).

Aging has pronounced effects on mammalian tissues and cells, but the impacts of aging on salivary gland function are relatively unknown. This study aims to evaluate the effects of aging on submandibular gland (SMG) and parotid gland (PG) functions in the male senescence-accelerated mouse. In vivo analysis at the systemic level revealed that salivary secretion induced by pilocarpine, a muscarinic agonist, from the SMG was significantly decreased in aged mice, whereas salivary secretion from the PG was not affected. To evaluate organ-level function, the SMG was perfused with the muscarinic agonists carbachol and calcium ionophore A23187 ex vivo to induce salivary secretion, and decreased saliva production was also observed in the aged SMG. Histological analysis revealed the presence of CD4-positive lymphocytes infiltrating the aged SMG. Furthermore, real-time PCR revealed that the aged SMG exhibited accelerated cell aging, increased levels of the inflammatory cytokine interleukin-6, and decreased mRNA levels of the water channel protein aquaporin-5 (AQP5). In summary, these results demonstrate that SMG function in aged mice was diminished, and that cell senescence, chronic inflammation, and the decreased gene expression of AQP5 are the likely causes of hyposalivation in the SMG of aged mice.

Characterization of air-liquid interface culture of A549 alveolar epithelial cells

Alveolar epithelia play an essential role in maintaining the integrity and homeostasis of lungs, in which alveolar epithelial type II cells (AECII) are a cell type with stem cell potential for epithelial injury repair and regeneration. However, mechanisms behind the physiological and pathological roles of alveolar epithelia in human lungs remain largely unknown, partially owing to the difficulty of isolation and culture of primary human AECII cells. In the present study, we aimed to characterize alveolar epithelia generated from A549 lung adenocarcinoma cells that were cultured in an air-liquid interface (ALI) state. Morphological analysis demonstrated that A549 cells could reconstitute epithelial layers in ALI cultures as evaluated by histochemistry staining and electronic microscopy. Immunofluorescent staining further revealed an expression of alveolar epithelial type I cell (AECI) markers aquaporin-5 protein (AQP-5), and AECII cell marker surfactant protein C (SPC) in subpopulations of ALI cultured cells. Importantly, molecular analysis further revealed the expression of AQP-5, SPC, thyroid transcription factor-1, zonula occludens-1 and Mucin 5B in A549 ALI cultures as determined by both immunoblotting and quantitative RT-PCR assay. These results suggest that the ALI culture of A549 cells can partially mimic the property of alveolar epithelia, which may be a feasible and alternative model for investigating roles and mechanisms of alveolar epithelia in vitro.

Characterization of air-liquid interface culture of A549 alveolar epithelial cells.

Alveolar epithelia play an essential role in maintaining the integrity and homeostasis of lungs, in which alveolar epithelial type II cells (AECII) are a cell type with stem cell potential for epithelial injury repair and regeneration. However, mechanisms behind the physiological and pathological roles of alveolar epithelia in human lungs remain largely unknown, partially owing to the difficulty of isolation and culture of primary human AECII cells. In the present study, we aimed to characterize alveolar epithelia generated from A549 lung adenocarcinoma cells that were cultured in an air-liquid interface (ALI) state. Morphological analysis demonstrated that A549 cells could reconstitute epithelial layers in ALI cultures as evaluated by histochemistry staining and electronic microscopy. Immunofluorescent staining further revealed an expression of alveolar epithelial type I cell (AECI) markers aquaporin-5 protein (AQP-5), and AECII cell marker surfactant protein C (SPC) in subpopulations of ALI cultured cells. Importantly, molecular analysis further revealed the expression of AQP-5, SPC, thyroid transcription factor-1, zonula occludens-1 and Mucin 5B in A549 ALI cultures as determined by both immunoblotting and quantitative RT-PCR assay. These results suggest that the ALI culture of A549 cells can partially mimic the property of alveolar epithelia, which may be a feasible and alternative model for investigating roles and mechanisms of alveolar epithelia in vitro.

Overexpression of AQP5 Was Detected in Axillary Sweat Glands of Primary Focal Hyperhidrosis Patients.

BACKGROUND: The expression of aquaporin 5 (AQP5) in human axillary sweat glands has never been studied so far. OBJECTIVE: To detect the expression of AQP5 in axillary sweat glands of patients with primary focal hyperhidrosis (PFH) relative to control subjects. METHODS: The morphological characteristics and the number of sweat coils in axillary sweat glands were compared between two groups by using transmission electron microscopy. The expression of AQP5 was detected by immunohistochemistry, Western blot analysis, and real-time transcription polymerase chain reaction. RESULTS: There were no significant differences between the two groups in terms of morphological characteristics and the number of sweat coils in axillary sweat glands. The expressions of AQP5 protein and AQP5 mRNA were significantly higher in the patient group than in the control group. CONCLUSION: AQP5 is involved in the secretion of human axillary sweat glands. The overexpression of AQP5 in sweat glands is probably one pathogenetic mechanism underlying PFH.

Morphology and Aquaporin Immunohistochemistry of the Uterine Tube of Saanen Goats (Capra hircus): Comparison Throughout the Reproductive Cycle.

The expression of six different aquaporins (AQP1, 2, 3, 4, 5 and 9), integral membrane water channels that facilitate bi-directional passive movement of water, was investigated by immunohistochemistry in the uterine tube of pre-pubertal and adult Saanen goats (Capra hircus), comparing the different phases of the oestrous cycle. Regional morphology and secretory processes were markedly different during the goat oestrous cycle. The tested AQP molecules showed different expression patterns in comparison with already studied species. AQP1-immunoreactivity was evidenced at the endothelium of blood vessels and in nerve fibres, regardless of the tubal tract and cycle period. AQP4-immunoreactivity was shown on the lateral plasmalemma in the basal third of the epithelial cells at infundibulum and ampulla level in the cycling goats, more evidently during follicular than during luteal phase. No AQP4-immunoreactivity was noticed at the level of the isthmus region, regardless of the cycle phase. AQP5-immunoreactivity, localized at the apical surface of epithelial cells, increased from pre-puberty to adulthood. Thereafter, AQP5-immunoreactivity was prominent during the follicular phase, when it strongly decorated the apical plasmalemma of all epithelial cells at ampullary level. During luteal phase, immunoreactivity was discontinuous, being weak to strong at the apex of the secretory cells protruding into the lumen. In the isthmus region, the strongest AQP5-immunoreactivity was seen during follicular phase, with a clear localization in the apical plasmalemma of all the epithelial cells and also on the lateral plasmalemma. AQP2, 3 and 9 were undetectable all along the goat uterine tube. Likely, a collaboration of different AQP molecules sustains the fluid production in the goat uterine tube. AQP1-mediated transudation from the blood capillaries, together with permeation of the epithelium by AQP4 in the basal rim of the epithelial cells and final intervening of apical AQP5, could be involved in fluid production as well as in secretory processes.

Aquaporin 5 expression is frequent in prostate cancer and shows a dichotomous correlation with tumor phenotype and PSA recurrence.

Aquaporin 5 (AQP5) is an androgen-regulated member of a family of small hydrophobic integral transmembrane water channel proteins regulating cellular water homeostasis and growth signaling. To evaluate its clinical impact and relationship with key genomic alterations in prostate cancer, AQP5 expression was analyzed by immunohistochemistry on a tissue microarray containing 12427 prostate cancers. The analysis revealed weak to moderate immunostaining in normal prostate epithelium. In prostate cancers AQP5 staining levels were more variable and also included completely negative and highly overexpressing cases. Negative, weak, moderate, and strong AQP5 staining was found in 25.0%, 32.5%, 32.5%, and 10.0% of 10239 interpretable tumors. Comparison of AQP5 expression levels with tumor characteristics showed a dichotomous pattern with both high and low staining levels being linked to unfavorable tumor phenotype. AQP5 was negative in 28%, 23%, 24%, and 35% of tumors with Gleason score ≤3 + 3, 3 + 4, 4 + 3 and ≥4 + 4, while the rate of strongly positive cases continuously increased from 7.0% over 10.0% and 12.0% to 13.0% in cancers with Gleason score ≤3 + 3, 3 + 4, 4 + 3 and ≥4 + 4. AQP5 expression was also related to ERG positivity and phosphatase and tensin homolog (PTEN) deletion (P < .0001 each). Strong AQP5 positivity was seen in 15.5% of ERG-positive and 5.8% of ERG-negative cancers (P < .0001) as well as in 14.7% of cancers with PTEN deletion and 9.4% of cancers without PTEN deletion. Remarkably, both negativity and strong positivity of AQP5 were linked to unfavorable disease outcome. This was however only seen in subgroups defined by TMPRSS2-ERG fusion and/or PTEN deletion. In summary, AQP5 can be both overexpressed and lost in subgroups of prostate cancers. Both alterations are linked to unfavorable outcome in molecularly defined cancer subgroups. It is hypothesized that this dichotomous role of AQP5 is due to two highly different mechanisms as to how the protein can influence cancer cells, that is, hydraulic motility regulation and Ras/MAPK pathway activation.

Effect of Prenatal and Neonatal Anti-Androgen Flutamide Treatment on Aquaporin 5 Expression in the Adult Porcine Ovary.

The growth of ovarian follicles is accompanied by fluid-filled antrum formation. Water movement within the follicular wall is predominantly transcellular via membranous water channels named aquaporins (AQPs). Androgens are important regulators of mammalian folliculogenesis, and their prenatal and/or neonatal deficiency affects female fertility in adulthood. Therefore, this study was performed to determine whether gestational or neonatal exposure to the anti-androgen flutamide influences androgen-dependent AQP5 expression in pre-antral and large antral follicles of adult pigs. Flutamide was injected into pregnant gilts between days 80 and 88 of gestation and into female piglets between days 2 and 10 post-natally. The ovaries were collected from flutamide-treated and non-treated (control) sexually mature pigs. In pre-antral follicles, AQP5 mRNA and protein levels were both downregulated following maternal (p < 0.01 and p < 0.01, respectively) and neonatal (p < 0.01 and p < 0.01, respectively) flutamide exposure. Likewise, the expression of mRNA (p < 0.01 and p < 0.001, respectively) and protein (p < 0.05 and p < 0.01, respectively) for AQP5 were diminished in large antral follicles in both groups. Immunohistochemistry showed decreased intensity of AQP5 immunoreaction in pre-antral (p < 0.01) and large antral (p < 0.001) follicles following flutamide treatment. Moreover, radioimmunological analysis revealed that changes observed in AQP5 expression corresponded with diminished follicular androgens production after both maternal (p < 0.05 and p < 0.05, respectively) and neonatal (p < 0.05 and p < 0.01, respectively) flutamide administration. Therefore, AQP5 appears to be a potential regulator of follicular fluid accumulation, under androgen control, and may be a key factor in antral follicle growth.

Modulation by thyroid hormone of myosin light chain phosphorylation and aquaporin 5 protein expression in intact lung

Myosin light chain kinase (MLCK) may play a key role in cellular contraction, paracellular permeability and lung water homeostasis. In vitro, thyroid hormones (THs) potently inhibit MLCKactivation and, hence, MLC phosphorylation. Whether similar effect is exerted by THs in in vivo systems is not known. Therefore, we investigated the effects of hypothyroid (HO) and hyperthyroid (HR) states on the level of phospho-MLC, aquaporin 5 (AQP5) protein expression, and water holding capacity in the rat lung. Alterations in thyroid state were induced by adding methimazole or levothyroxine (L-T4) to animals’ drinking water. Serum TH concentration and thyroid gland histomorphology were assessed to verify the onset of the thyroid state. Lung phospho-MLC and AQP5 proteins were assessed by Western blotting and immunohistochemistry. Lung extravascular water content was estimated by the tissue wet weight-to-dry weight (W/D) ratio. The HO state induced significant increases in the expression of lung phospho-MLC and AQP5 proteins. In contrast, the HR state caused moderate decreases in lung phospho-MLC and AQP5 proteins. While lung water holding capacity was significantly increased in HO animals, it was significantly reduced in HR animals. The data of this study show that THs are able to modulate MLC phosphorylation in in vivo systems. Besides, they suggest that the circulating level of THs may alter lung fluid balance not only through expression of water channels but also through regulation of cellular contraction and paracellular permeability

NFIB regulates embryonic development of submandibular glands.

NFIB (nuclear factor I B) is a NFI transcription factor family member, which is essential for the development of a variety of organ systems. Salivary gland development occurs through several stages, including prebud, bud, pseudoglandular, canalicular, and terminal. Although many studies have been done to understand mouse submandibular gland (SMG) branching morphogenesis, little is known about SMG cell differentiation during the terminal stages. The goal of this study was to determine the role of NFIB during SMG development. We analyzed SMGs from wild-type and Nfib-deficient mice (Nfib (-/-)). At embryonic (E) day 18.5, SMGs from wild-type mice showed duct branching morphogenesis and differentiation of tubule ductal cells into tubule secretory cells. In contrast, SMGs from Nfib (-/-) mice at E18.5 failed to differentiate into tubule secretory cells while branching morphogenesis was unaffected. SMGs from wild-type mice at E16.5 displayed well-organized cuboidal inner terminal tubule cells. However, SMGs from Nfib (-/-) at E16.5 displayed disorganized inner terminal tubule cells. SMGs from wild-type mice at E18.5 became fully differentiated, as indicated by a high degree of apicobasal polarization (i.e., presence of apical ZO-1 and basolateral E-cadherin) and columnar shape. Furthermore, SMGs from wild-type mice at E18.5 expressed the protein SMGC, a marker for tubule secretory cells. However, SMGs from Nfib (-/-) mice at E18.5 showed apicobasal polarity, but they were disorganized and lost the ability to secrete SMGC. These findings indicate that the transcription factor NFIB is not required for branching morphogenesis but plays a key role in tubule cell differentiation during mouse SMG development.

Use of aquaporins 1 and 5 levels as a diagnostic marker in mild-to-moderate adult-onset asthma.

Characteristic features of asthma include airway inflammation and hyperactivity, mucus hypersecretion, mucosal edema, and airway remodeling. These features could be due to pathological water transport across pulmonary epithelia and aquaporins (AQPs) have recently been isolated as key proteins in fluid transportation in the human respiratory tract. We aimed to evaluate the role of aquaporins in the pathogenesis of asthma and their possible use a diagnostic marker of the disease. A total of 110 hospitalized and outpatients with mild to moderate adult-onset asthma were invited to participate in this study and 34 submitted an induced sputum sample adequate for analysis. The amount of AQP1, AQP5 and MUC5AC were measured with ELISA assay. The amount of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ and IL-17 in both serum and sputum were measured with Cytometry Bead Array (CBA kit). Our results suggest that sputum AQP5, AQP1 and MUC5AC are all in a good correlation (r=0.498 between AQP5 and AQP1, r=0.529 and r=0.661 between MUC5AC and AQP5 or AQP1, respectively, all P<0.05). The AUC value for AQP1 and AQP5 to diagnose asthma were 0.729 and 0.745, respectively. In conclusion, water homeostasis plays an important role in maintaining adequate fluid transportation within the lung and is involved in the pathogenesis of asthma. Our results suggest that AQP may influence pulmonary physiology that their dysfunction can contribute to pulmonary pathogenesis, such as asthma. Moreover, their quantification could serve as biomarkers for the diagnosis of asthma.

Establishment of functional acinar-like cultures from human salivary glands.

Disorders of human salivary glands resulting from therapeutic radiation treatment for head and neck cancers or from the autoimmune disease Sjögren syndrome (SS) frequently result in the reduction or complete loss of saliva secretion. Such irreversible dysfunction of the salivary glands is due to the impairment of acinar cells, the major glandular cells of protein, salt secretion, and fluid movement. Availability of primary epithelial cells from human salivary gland tissue is critical for studying the underlying mechanisms of these irreversible disorders. We applied 2 culture system techniques on human minor salivary gland epithelial cells (phmSG) and optimized the growth conditions to achieve the maintenance of phmSG in an acinar-like phenotype. These phmSG cells exhibited progenitor cell markers (keratin 5 and nanog) as well as acinar-specific markers-namely, α-amylase, cystatin C, TMEM16A, and NKCC1. Importantly, with an increase of the calcium concentration in the growth medium, these phmSG cells were further promoted to acinar-like cells in vitro, as indicated by an increase in AQP5 expression. In addition, these phmSG cells also demonstrated functional calcium mobilization, formation of epithelial monolayer with high transepithelial electrical resistance (TER), and polarized secretion of α-amylase secretion after ß-adrenergic receptor stimulation. Taken together, suitable growth conditions have been established to isolate and support culture of acinar-like cells from the human salivary gland. These primary epithelial cells can be useful for study of molecular mechanisms involved in regulating the function of acinar cells and in the loss of salivary gland function in patients.

Reinnervated nerves contribute to the secretion function and regeneration of denervated submandibular glands in rabbits.

This study aimed to investigate the contribution of redistributed nerves in the secretory function and regeneration of a denervated submandibular gland (SMG). The postganglionic parasympathetic and sympathetic denervated SMGs of rabbits were wrapped in polyester or acellular dermal matrices to block nerve regeneration either partially or completely. Submandibular glands were removed 4, 8, 16, and 24 wk after the operation and examined histologically. Furthermore, the aquaporin-5 (AQP5), muscarinic-3 (M3), and ß1-adrenergic receptors were evaluated by immunofluorescence and western blot analysis. After denervation, salivary flow was decreased and acinar cells were atrophic, and the expression levels of the M3, ß1-adrenergic, and AQP5 receptors were decreased. However, both impaired secretion function and atrophic parenchyma were gradually ameliorated with the growing redistribution of parasympathetic and sympathetic nerves. Apoptosis was markedly inhibited and expression of the M3, ß1-adrenergic, and AQP5 receptors was increased after reinnervation. In contrast, SMGs without reinnervated nerves maintained hyposecretion and atrophic parenchyma. In conclusion, reinnervated nerves in a rabbit's denervated SMG played an important role in the secretion function and regeneration of SMGs via up-regulation of the expression of neurotransmitter receptors and AQP5.

Mucosal expression of aquaporin 5 and epithelial barrier proteins in chronic rhinosinusitis with and without nasal polyps.

OBJECTIVES: The purpose of this study is to characterize the association between altered epithelial barrier function, represented by changes in histology and differential expression of the mucosal water membrane permeability protein aquaporin 5 (AQP5), and the pathophysiology of chronic refractory sinusitis (CRS) in patients with and without nasal polyposis. STUDY DESIGN: Prospective clinical study. SETTING: Tertiary rhinology referral center. PARTICIPANTS: Sinonasal samples were obtained from seven CRS subjects with nasal polyps (CRSwNP), seven CRS without nasal polyposis (CRSsNP), and five control healthy patients. METHODS: Mucosal membrane changes were evaluated through hematoxylin and eosin staining of the membrane barrier and immunohistochemical staining of AQP5 expression, a membrane channel protein that affects trans-epithelial water permeability and tissue edema. AQP5 expression was confirmed by real-time PCR (rt-PCR) and western blot. Levels of other membrane proteins, including E-cadherin and Septin-2, were also assessed. RESULTS: CRSwNP patients showed substantial histologic evidence of membrane remodeling with increased edema and glandular hyperplasia. The epithelial expression of AQP5 was significantly lower in CRSwNP as compared to CRSsNP or control. There was no significant difference in the expression of E-cadherin and Septin-2. CONCLUSIONS: Collectively, these data suggest that the mucosal epithelial barrier is compromised in the context of CRS (predominantly in CRSwNP) when compared to control and that AQP5 acts as a key tight junction protein in the maintenance of mucosal water homeostasis. We hypothesize that AQP5 plays a possible role in the pathophysiology of mucosal edema and polyp formation.

Hypersensitive mAChRs are involved in the epiphora of transplanted glands.

Autologous transplantation of the submandibular gland is an effective treatment for severe dry eye syndrome. However, more than 40% of patients experience epiphora 3 to 6 months after transplantation. The underlying mechanism of epiphora remains to be elucidated. To investigate the potential roles of muscarinic acetylcholine receptors (mAChRs) in the induction of epiphora in transplanted glands, we assessed and found elevated mRNA and protein expression of M1- and M3-mAChR in transplanted glands from epiphora patients. The content of inositol 1, 4, 5-trisphosphate was also elevated. Moreover, carbachol (5 and 10 µM) induced greater increase of [Ca(2+)]i in isolated epiphora submandibular cells than in controls. Although aquaporin-5 (AQP5) content and distribution in the apical and lateral plasma of epiphora glands did not change, AQP5 content was reduced in lipid microdomains (lipid rafts and caveolae) but increased in non-lipid microdomains compared with controls. Carbachol (10 µM) increased the ratio of non-lipid microdomain to total AQP5 in the cultured control submandibular gland tissue. Taken together, these results indicated that hypersensitive mAChRs might be involved in the epiphora of transplanted submandibular glands by modulating AQP5 trafficking.

Calcium signaling and cell volume regulation are altered in Sjögren's Syndrome.

OBJECTIVE: Sjögren's Syndrome (SS) is a chronic autoimmune disease, leading to deficient secretion from salivary and lacrimal glands. Saliva production is normally increased by cholinergic innervation, giving rise to intracellular calcium signaling and water transport through water channels (aquaporins, AQPs). The aim of this study was to investigate possible pathophysiological changes in cell volume regulation, AQP expression and localization, and intracellular calcium signaling in glandular cells from SS patients compared to controls. MATERIALS AND METHODS: A total of 35 SS patients and 41 non-SS controls were included. Real time qPCR was combined with immunohistochemistry to analyze the mRNA expression and cellular distribution of AQP1, 3 and 5. Cell volume regulation and intracellular calcium signaling were examined in fresh acinar cells. RESULTS: We show for the first time a reduced mRNA expression of AQP1 and 5 in SS compared to controls, accompanied by a decrease in staining intensity of AQP1, 3 and 5 in areas adjacent to local lymphocytic infiltration. Furthermore, we observed that the SS cells' capacity for volume regulation was abnormal. Similarly, the calcium response after parasympathetic agonist (carbachol) stimulation was markedly decreased in SS cells. CONCLUSIONS: It is concluded that mRNA expression of AQP1 and 5, protein distribution of AQP1, 3 and 5, glandular cell volume regulation and intracellular calcium signaling are all altered in SS, pointing to possible pathophysiological mechanisms in SS.