Morphometric study of the postnatal growth of the parotid gland of the mouse

Ribeiro, Tiago Turri de Castro; Sottovia, André Dotto; Cestari, Tânia Mary; Taga, Rumio

doi:10.1590/s1806-83242006000100004

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…5 a and b). Although sexual dimorphism in salivary glands at the level of cellular architecture, composition of saliva, and regulation of salivary glands is well documented in mice (46)(47)(48)(49), our findings provide insights into gender-related physiological and molecular differences in the mechanisms of saliva formation.…”

Section: Gender-specific Differences In the Properties Of Paracellulamentioning

confidence: 79%

Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex

Kawedia

Nieman²,

Boivin³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

123

100

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To investigate potential physiological interactions between the transcellular and paracellular pathways of water transport, we asked whether targeted deletion of Aquaporin 5 (AQP5), the major transcellular water transporter in salivary acinar cells, affected paracellular transport of 4-kDa FITC-labeled dextran (FITC-D), which is transported through the paracellular but not the transcellular route. After i.v. injection of FITC-D into either AQP5 wild-type or AQP5؊/؊ mice and saliva collection for fixed time intervals, we show that the relative amount of FITC-D transported in the saliva of AQP5؊/؊ mice is half that in matched AQP5؉/؉ mice, indicating a 2-fold decrease in permeability of the paracellular barrier in mice lacking AQP5. We also found a significant difference in the proportion of transcellular vs. paracellular transport between male and female mice. Freeze-fracture electron microscopy revealed an increase in the number of tight junction strands of both AQP5؉/؉ and AQP5؊/؊ male mice after pilocarpine stimulation but no change in strand number in female mice. Average acinar cell volume was increased by Ϸ1.4-fold in glands from AQP5؊/؊ mice, suggesting an alteration in the volumesensing machinery of the cell. Western blots revealed that expression of Claudin-7, Claudin-3, and Occludin, critical proteins that regulate the permeability of the tight junction barrier, were significantly decreased in AQP5؊/؊ compared with AQP5؉/؉ salivary glands. These findings reveal the existence of a genderinfluenced molecular mechanism involving AQP5 that allows transcellular and paracellular routes of water transport to act in conjunction.epithelium ͉ fluid absorption and secretion T he proper transport of electrolytes and water across epithelial barriers is of vital importance to the maintenance of normal physiological homeostasis in all animals (1, 2). Fluid is moved either across the plasma membranes of the cells that comprise the epithelial layer (transcellular transport) or between these cells, through the tight junction complex (TJC) that forms a barrier (paracellular transport). Together, the transcellular and paracellular pathways are capable of transporting large volumes of fluid, estimated at 200 liters per day in a 70-kg human (1).There is considerable complexity in the mechanisms that determine the usage of paracellular vs. transcellular routes of water transport. For example, in the kidney, transport of water is accomplished mainly through paracellular transport in the proximal nephron (3), whereas highly regulated transcellular transport is carried out in the distal nephron and collecting duct (4). Similar complexities are likely to exist in the secretion and absorption of water in the gut and the secretion of fluids by exocrine glands such as the salivary gland and pancreas.In an attempt to determine the ratio of paracellular to transcellular transport, Murakami et al. (5,6) used ex vivo perfused rat submandibular salivary glands and showed that the majority of water is transported through the paracellular ...

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Section: Gender-specific Differences In the Properties Of Paracellulamentioning

confidence: 79%

Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex

Kawedia

Nieman²,

Boivin³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

123

100

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Salivary Gland Homeostasis Is Maintained through Acinar Cell Self-Duplication

2015

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Summary Current dogma suggests that salivary gland homeostasis is stem cell-dependent. However, the extent of stem cell contribution to salivary gland maintenance has not been determined. We have investigated acinar cell replacement during homeostasis, growth and regeneration, using an inducible CreERT2 expressed under the control of the Mist1 gene locus. Genetic labeling, followed by a chase period, showed that acinar cell replacement is not driven by the differentiation of unlabeled stem cells. Analysis using R26Brainbow2.1 reporter revealed continued proliferation and clonal expansion of terminally differentiated acinar cells in all major salivary glands. Induced injury also demonstrated the regenerative potential of pre-labeled acinar cells. Our results support a revised model for salivary gland homeostasis based predominantly on self-duplication of acinar cells, rather than on differentiation of stem cells. The proliferative capacity of differentiated acinar cells may prove critical in the implementation of cell-based strategies to restore the salivary glands.

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Salivary Gland Protein Expression after Bion-M1 and Space Shuttle STS-135 Missions

Mednieks

Khatri

Hand

2015

Gravitational and Space Research

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Secretory proteins produced by salivary glands are stored in granules and released into saliva. Rodent salivary glands are a reliable experimental model because they are morphologically and functionally similar to those of humans. To determine if the effects of microgravity on secretory proteins are increased on extended flights, their expression in mouse parotid glands, morphological, immunocytochemical, and biochemical/molecular methods were employed. Acinar cells of STS-135 (13 day) and Bion-M1 (30 day) flight animals showed an increase of autophagy and apoptosis, while duct cells contained vacuoles with endocytosed proteins. In STS-135, decreases were seen in the regulatory subunit of type II protein kinase A (RII) by Western blotting, and demilune cell and parotid protein (DCPP) and α-amylase (p<0.01) by immunogold labeling, while proline-rich proteins (PRPs, p<0.001) and parotid secretory protein (PSP, p<0.05) were increased. These results suggest microgravity effects on secretion are function-dependent. Microarray analyses showed significant changes in the expression of a number of genes, including components of the cyclic-3’,5’,-adenosine monophosphate (cyclic AMP) signaling pathway. Compared to habitat ground controls, mice from both flights exhibited altered expression of cyclic AMP-specific phosphodiesterases, adenylate cyclase isoforms, and several A-kinase anchoring proteins. Bion-M1 flight mice showed increases in gene expression for lysozyme and amylase, a decrease in PRPs, and RII expression was unchanged from control values. Secretory protein expression is altered by travel in space, representing a reversible adjustment to microgravity conditions. Ultimately, the goal is to develop a test kit using saliva — an easily obtained body fluid — to assess the physiologic effects of travel in space.

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Morphometric study of the postnatal growth of the parotid gland of the mouse

Cited by 4 publications

References 14 publications

Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex

Interaction between transcellular and paracellular water transport pathways through Aquaporin 5 and the tight junction complex

Salivary Gland Homeostasis Is Maintained through Acinar Cell Self-Duplication

Salivary Gland Protein Expression after Bion-M1 and Space Shuttle STS-135 Missions

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