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1.
Am J Physiol Lung Cell Mol Physiol ; 310(8): L733-46, 2016 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-26895644

RESUMO

Despite intense investigation, acute respiratory distress syndrome (ARDS) remains an enormous clinical problem for which no specific therapies currently exist. In this study, we used intratracheal lipopolysaccharide or Pseudomonas bacteria administration to model experimental acute lung injury (ALI) and to further understand mediators of the resolution phase of ARDS. Recent work demonstrates macrophages transition from a predominant proinflammatory M1 phenotype during acute inflammation to an anti-inflammatory M2 phenotype with ALI resolution. We tested the hypothesis that IL-4, a potent inducer of M2-specific protein expression, would accelerate ALI resolution and lung repair through reprogramming of endogenous inflammatory macrophages. In fact, IL-4 treatment was found to offer dramatic benefits following delayed administration to mice subjected to experimental ALI, including increased survival, accelerated resolution of lung injury, and improved lung function. Expression of the M2 proteins Arg1, FIZZ1, and Ym1 was increased in lung tissues following IL-4 treatment, and among macrophages, FIZZ1 was most prominently upregulated in the interstitial subpopulation. A similar trend was observed for the expression of macrophage mannose receptor (MMR) and Dectin-1 on the surface of alveolar macrophages following IL-4 administration. Macrophage depletion or STAT6 deficiency abrogated the therapeutic effect of IL-4. Collectively, these data demonstrate that IL-4-mediated therapeutic macrophage reprogramming can accelerate resolution and lung repair despite delayed use following experimental ALI. IL-4 or other therapies that target late-phase, proresolution pathways may hold promise for the treatment of human ARDS.


Assuntos
Interleucina-4/farmacologia , Macrófagos Alveolares/fisiologia , Síndrome do Desconforto Respiratório/imunologia , Animais , Avaliação Pré-Clínica de Medicamentos , Interleucina-4/uso terapêutico , Lipopolissacarídeos/farmacologia , Ativação de Macrófagos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Síndrome do Desconforto Respiratório/tratamento farmacológico , Linfócitos T Reguladores/imunologia
2.
Mucosal Immunol ; 7(6): 1440-51, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24850425

RESUMO

Acute respiratory distress syndrome (ARDS) causes significant morbidity and mortality each year. There is a paucity of information regarding the mechanisms necessary for ARDS resolution. Foxp3(+) regulatory T cells (Foxp3(+) T(reg) cells) have been shown to be an important determinant of resolution in an experimental model of lung injury. We demonstrate that intratracheal delivery of endotoxin (lipopolysaccharide) elicits alveolar epithelial damage from which the epithelium undergoes proliferation and repair. Epithelial proliferation coincided with an increase in Foxp3(+) T(reg) cells in the lung during the course of resolution. To dissect the role that Foxp3(+) T(reg) cells exert on epithelial proliferation, we depleted Foxp3(+) T(reg) cells, which led to decreased alveolar epithelial proliferation and delayed lung injury recovery. Furthermore, antibody-mediated blockade of CD103, an integrin, which binds to epithelial expressed E-cadherin decreased Foxp3(+) T(reg) numbers and decreased rates of epithelial proliferation after injury. In a non-inflammatory model of regenerative alveologenesis, left lung pneumonectomy, we found that Foxp3(+) T(reg) cells enhanced epithelial proliferation. Moreover, Foxp3(+) T(reg) cells co-cultured with primary type II alveolar cells (AT2) directly increased AT2 cell proliferation in a CD103-dependent manner. These studies provide evidence of a new and integral role for Foxp3(+) T(reg) cells in repair of the lung epithelium.


Assuntos
Células Epiteliais Alveolares/imunologia , Proliferação de Células , Síndrome do Desconforto Respiratório/imunologia , Mucosa Respiratória/imunologia , Linfócitos T Reguladores/imunologia , Células Epiteliais Alveolares/patologia , Animais , Antígenos CD/genética , Antígenos CD/imunologia , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Cadeias alfa de Integrinas/genética , Cadeias alfa de Integrinas/imunologia , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Knockout , Síndrome do Desconforto Respiratório/induzido quimicamente , Síndrome do Desconforto Respiratório/genética , Síndrome do Desconforto Respiratório/patologia , Mucosa Respiratória/patologia , Linfócitos T Reguladores/patologia
3.
FASEB J ; 20(12): 1974-81, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17012249

RESUMO

We report here the application of a previously described method to directly determine the CO2 permeability (P(CO2)) of the cell membranes of normal human red blood cells (RBCs) vs. those deficient in aquaporin 1 (AQP1), as well as AQP1-expressing Xenopus laevis oocytes. This method measures the exchange of (18)O between CO2, HCO3(-), and H2O in cell suspensions. In addition, we measure the alkaline surface pH (pH(S)) transients caused by the dominant effect of entry of CO2 vs. HCO3(-) into oocytes exposed to step increases in [CO2]. We report that 1) AQP1 constitutes the major pathway for molecular CO2 in human RBCs; lack of AQP1 reduces P(CO2) from the normal value of 0.15 +/- 0.08 (SD; n=85) cm/s by 60% to 0.06 cm/s. Expression of AQP1 in oocytes increases P(CO2) 2-fold and doubles the alkaline pH(S) gradient. 2) pCMBS, an inhibitor of the AQP1 water channel, reduces P(CO2) of RBCs solely by action on AQP1 as it has no effect in AQP1-deficient RBCs. 3) P(CO2) determinations of RBCs and pH(S) measurements of oocytes indicate that DIDS inhibits the CO2 pathway of AQP1 by half. 4) RBCs have at least one other DIDS-sensitive pathway for CO2. We conclude that AQP1 is responsible for 60% of the high P(CO2) of red cells and that another, so far unidentified, CO2 pathway is present in this membrane that may account for at least 30% of total P(CO2).


Assuntos
Aquaporina 1/metabolismo , Dióxido de Carbono/metabolismo , Membrana Eritrocítica/metabolismo , Animais , Bicarbonatos/metabolismo , Transporte Biológico , Permeabilidade da Membrana Celular/fisiologia , Membrana Eritrocítica/fisiologia , Humanos , Concentração de Íons de Hidrogênio , Oócitos , Isótopos de Oxigênio/metabolismo , Xenopus laevis
4.
Psychopharmacology (Berl) ; 186(1): 41-7, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16572264

RESUMO

RATIONALE: Since its earliest use in psychiatry, lithium has been known to alter body water homeostasis. Although lithium is also known to decrease the concentration of inositol, an important brain osmolyte, little is known of the effects of lithium on brain water homeostasis. OBJECTIVE: To determine whether lithium alters brain water homeostasis, and, if so, whether the mechanism involves changes in inositol concentration. MATERIALS AND METHODS: Rats were fed regular food or regular food plus lithium chloride for either 11 days or 5 weeks. Brains were dissected and assayed for tissue water by the wet-dry method and for inositol by gas chromatography-mass spectrometry. RESULTS: We found a statistically significant (p=0.05, corrected) 3.1% mean elevation in frontal cortex tissue water in 5-week lithium-fed rats (86.7+/-3.9%), compared to control rats (83.6+/-2.6%). Inositol concentration correlated inversely with percent tissue water (r=-0.50, p=0.003, corrected) in pooled samples of 5-week lithium-fed rats, and was significantly lower in frontal cortex and hippocampus of 5-week lithium-fed rats, compared to controls. Rats fed lithium for 11 days did not differ significantly from controls on either variable. CONCLUSIONS: This is the first report of a lithium-induced increase in brain tissue water. Although the mechanism is unclear, it does not appear to result from changes in brain inositol concentration or blood sodium concentration. This finding may have implications for the therapeutic or toxic effects of lithium on brain, because increased tissue water can augment cell excitability.


Assuntos
Lobo Frontal/química , Homeostase/efeitos dos fármacos , Lítio/farmacologia , Água/análise , Animais , Cerebelo/química , Cerebelo/efeitos dos fármacos , Lobo Frontal/efeitos dos fármacos , Hipocampo/química , Hipocampo/efeitos dos fármacos , Inositol/análise , Masculino , Ratos , Ratos Sprague-Dawley
7.
Protein Expr Purif ; 22(1): 148-58, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11388813

RESUMO

Mammalian BiP/GRP78 and Escherichia coli DnaK belong to the highly conserved hsp70 family and function as molecular chaperones in the endoplasmic reticulum or the cytosol, respectively. Induction of murine BiP/GRP78 expression in E. coli leads to growth arrest and cell death, independent of the bacterial strain and vector used. Analysis of various BiP constructs and mutants shows that the dominant-lethal phenotype is induced specifically by the expression of the 13.7-kDa C-terminal domain and abolished by a single substitution in that region. Deletion of that region also results in nontoxic gene products that can be overexpressed and purified to homogeneity. The nontoxic mutants are highly expressed in E. coli, representing up to 20% of the soluble fraction. They are catalytically active, depolymerize upon binding ATP or synthetic peptide, and interact with the J-domain of the DnaJ-like accessory protein, MTJ1, with near wild-type affinity. Our data indicate that the cytotoxic effect encountered during overexpression of recombinant proteins can be caused by a single domain and can be alleviated by a specific mutation or deletion in that region without altering the catalytic properties of the enzyme.


Assuntos
Proteínas de Transporte/isolamento & purificação , Proteínas de Transporte/metabolismo , Proteínas de Choque Térmico , Chaperonas Moleculares/isolamento & purificação , Chaperonas Moleculares/metabolismo , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/isolamento & purificação , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/toxicidade , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/toxicidade , Catálise , Divisão Celular , Dicroísmo Circular , Chaperona BiP do Retículo Endoplasmático , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Cinética , Camundongos , Modelos Moleculares , Chaperonas Moleculares/genética , Chaperonas Moleculares/toxicidade , Fenótipo , Mutação Puntual/genética , Ligação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/toxicidade , Supressão Genética/genética
8.
Lab Invest ; 81(2): 143-8, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11232635

RESUMO

Patients with Sjögren's syndrome (SS) suffer from deficient secretion of saliva due to an autoimmune destruction of salivary glands, however, glandular dysfunction also occurs without destruction. Based upon its abnormal distribution in SS salivary glands, a potential role for the water channel protein aquaporin-5 (AQP5) is proposed in the pathogenesis of SS. The immunohistochemical distribution of AQP5 was compared in minor salivary gland biopsies obtained from women after informed consent: primary SS (53.2 +/- 14 years old, n = 10), healthy volunteers (46.2 +/- 17 years old, n = 10), patients with sarcoidosis (37 and 48 years old), and patients with non-specific sialoadenitis (54 and 61 years old). Biopsies from normal subjects revealed AQP5 primarily at the apical membrane of the salivary gland acinus. In contrast, biopsies from SS patients revealed AQP5 primarily at the basal membranes of the acinus. The AQP5 distribution in biopsies from patients with other dry mouth disorders, such as non-specific sialoadenitis or sarcoidosis, was similar to biopsies from control subjects. Computer-assisted microscopy was performed to quantitatively evaluate AQP5 distribution in the immunoreactive acini of both SS and control subjects. Biopsies from SS patients had higher labeling indices (percentage of acinus area immunoreactive for AQP5) at the basal membrane when compared with biopsies from control subjects. In contrast, biopsies of SS patients exhibited lower labeling indices at the apical membrane when compared with biopsies from control subjects. To verify the specificity of the AQP5 antibody, Western blot analysis was performed on membranes from Xenopus oocytes injected with AQP5 cRNA or on membranes from minor salivary glands of control subjects and SS patients. In each case, the immunoblots had a 27 kd band, corresponding to the expected molecular weight of AQP5. Abnormal distribution of AQP5 in salivary gland acini is likely to contribute to the deficiency of fluid secretion, which is a defining feature of Sjögren's syndrome.


Assuntos
Aquaporinas/análise , Proteínas de Membrana , Glândulas Salivares/patologia , Síndrome de Sjogren/patologia , Adulto , Idoso , Sequência de Aminoácidos , Especificidade de Anticorpos , Aquaporina 5 , Aquaporinas/química , Epitopos/química , Feminino , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Índice Mitótico , Dados de Sequência Molecular , Mucolipidoses/patologia , Valores de Referência , Glândulas Salivares/citologia , Sarcoidose/patologia
9.
Lancet ; 357(9257): 688-9, 2001 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-11247557

RESUMO

Dry eyes and dry mouth are clinical hallmarks of Sjögren's syndrome. We assessed the distribution of aquaporin-5 (AQP5) in lacrimal gland biopsy samples. Healthy controls and patients with Mikulicz's disease or non-Sjögren's syndrome dry eye had the expected apical distribution of AQP5 in lacrimal acinar cells. By contrast, cytoplasmic AQP5 was seen in patients with Sjögren's syndrome. Sodium channel and sodium-potassium ATPase distributions were normal in all groups. These findings show a selective defect in lacrimal gland AQP5 trafficking in Sjögren's syndrome that might contribute to decreased lacrimation and dry eye in these patients.


Assuntos
Aquaporinas/metabolismo , Aparelho Lacrimal/metabolismo , Proteínas de Membrana , Síndrome de Sjogren/metabolismo , Aquaporina 5 , Citoplasma/metabolismo , Humanos
11.
Proc Natl Acad Sci U S A ; 98(5): 2894-8, 2001 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-11226337

RESUMO

Aquaporin-1 (AQP1) water channel protein expression is increased by hypertonic stress. The contribution of changes in protein stability to hypertonic induction of AQP1 have not been described. Incubation of BALB/c fibroblasts spontaneously expressing AQP1 with proteasome inhibitors increased AQP1 expression, suggesting basal proteasome-dependent degradation of the protein. Degradation by the proteasome is thought to be triggered by polyubiquitination of a target protein. To determine whether AQP1 is ubiquitinated, immunoprecipitation with anti-AQP1 antibodies was performed, and the resultant samples were probed by protein immunoblot for the presence of ubiquitin. Immunoblots demonstrated ubiquitination of AQP1 under control conditions that increased after treatment with proteasome inhibitors (MG132, lactacystin). Exposure of cells to hypertonic medium for as little as 4 h decreased ubiquitination of AQP1, an effect that persisted through 24 h in hypertonic medium. Using metabolic labeling with [(35)S]methionine, the half-life of AQP1 protein under isotonic conditions was found to be <4 h. AQP1 protein half-life was markedly increased by exposure of cells to hypertonic medium. These observations provide evidence that aquaporins are a target for ubiquitination and proteasome-dependent degradation. Additionally, these studies demonstrate that reduced protein ubiquitination and increased protein stability lead to increased levels of AQP1 expression during hypertonic stress.


Assuntos
Aquaporinas/metabolismo , Ubiquitinas/metabolismo , Animais , Aquaporina 1 , Células Cultivadas , Cisteína Endopeptidases/efeitos dos fármacos , Inibidores de Cisteína Proteinase/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Complexos Multienzimáticos/efeitos dos fármacos , Pressão Osmótica , Complexo de Endopeptidases do Proteassoma
12.
J Biol Chem ; 275(12): 9070-7, 2000 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-10722758

RESUMO

Aquaporin-5 (AQP5) is a water channel protein expressed in lung, salivary gland, and lacrimal gland epithelia. Each of these sites may experience fluctuations in surface liquid osmolarity; however, osmotic regulation of AQP5 expression has not been reported. This study demonstrates that AQP5 is induced by hypertonic stress and that induction requires activation of extracellular signal-regulated kinase (ERK). Incubation of mouse lung epithelial cells (MLE-15) in hypertonic medium produced a dose-dependent increase in AQP5 expression; AQP5 protein peaked by 24 h and returned to baseline levels within hours of returning cells to isotonic medium. AQP5 induction was observed only with relatively impermeable solutes, suggesting an osmotic pressure gradient is required for induction. ERK was selectively activated in MLE-15 cells by hypertonic stress, and inhibition of ERK activation with two distinct mitogen-activated extracellular regulated kinase kinase (MEK) inhibitors, U0126 and PD98059, blocked AQP5 induction. AQP5 induction was also observed in the lung, salivary, and lacrimal glands of hyperosmolar rats, suggesting potential physiologic relevance for osmotic regulation of AQP5 expression. This report provides the first example of hypertonic induction of an extrarenal aquaporin, as well as the first association between mitogen-activated protein kinase signaling and aquaporin expression.


Assuntos
Aquaporinas/genética , Sistema de Sinalização das MAP Quinases , Proteínas de Membrana , Pressão Osmótica , Animais , Aquaporina 5 , Ativação Enzimática , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Flavonoides/farmacologia , Regulação da Expressão Gênica , Aparelho Lacrimal/metabolismo , Pulmão/citologia , Pulmão/metabolismo , Masculino , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Ratos , Ratos Sprague-Dawley , Glândula Submandibular/metabolismo
13.
Mol Med Today ; 6(2): 60-5, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10652478

RESUMO

The molecular basis of membrane water-permeability remained elusive until the recent discovery of the aquaporin water-channel proteins. The fundamental importance of these proteins is suggested by their conservation from bacteria through plants to mammals. Ten mammalian aquaporins have thus far been identified, each with a distinct distribution. In the kidney, lung, eye and brain, multiple water-channel homologs are expressed, providing a network for water transport in those locations. It is increasingly clear that alterations in aquaporin expression or function can be rate-limiting for water transport across certain membranes. Aquaporins are likely to prove central to the pathophysiology of a variety of clinical conditions from diabetes insipidus to various forms of edema and, ultimately, they could be a target for therapy in diseases of altered water homeostasis.


Assuntos
Aquaporinas/metabolismo , Doença , Água/metabolismo , Animais , Aquaporinas/química , Aquaporinas/genética , Encéfalo/metabolismo , Eritrócitos/metabolismo , Eritrócitos/patologia , Olho/metabolismo , Olho/fisiopatologia , Homeostase , Humanos , Rim/metabolismo , Rim/fisiopatologia , Sistema Respiratório/metabolismo , Glândulas Salivares/metabolismo , Glândulas Salivares/fisiopatologia
16.
Am J Respir Cell Mol Biol ; 18(4): 554-61, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9533944

RESUMO

We investigated the role of keratinocyte growth factor (KGF) in regulation of alveolar epithelial cell (AEC) phenotype in vitro. Effects of KGF on cell morphology, expression of surfactant apoproteins A, B, and C (SP-A, -B, and -C), and expression of aquaporin 5 (AQP5), a water channel present in situ on the apical surface of alveolar type I (AT1) cells but not expressed in alveolar type II (AT2) cells, were evaluated in AECs grown in primary culture. Observations were made on AEC monolayers grown in serum-free medium without KGF (control) or grown continuously in the presence of KGF (10 ng/ml) from either Day 0 (i.e., the time of plating) or Day 4 or 6 through Day 8 in culture. AECs monolayers express AQP5 only on their apical surfaces as determined by cell surface biotinylation studies. Control AECs grown in the absence of KGF through Day 8 express increasing levels of AQP5, consistent with transition toward the AT1 cell phenotype. Exposure of AECs to KGF from Day 0 results in decreased AQP5 expression, retention of a cuboidal morphology, and greater numbers of lamellar bodies relative to control on Day 8 in culture. AECs treated with KGF from Day 4 or 6 exhibit a decrease in AQP5 expression through subsequent days in culture, as well as an increase in expression of surfactant apoproteins. These data, showing that KGF both prevents and reverses the increase in AQP5 (and decrease in surfactant apoprotein) expression that accompanies progression of the AT2 toward the AT1 cell phenotype, support the concepts that transdifferentiation between AT2 and AT1 cell phenotypes is at least partially reversible and that KGF may play a major role in modulating AEC phenotype.


Assuntos
Aquaporinas , Fatores de Crescimento de Fibroblastos , Substâncias de Crescimento/farmacologia , Proteínas de Membrana , Alvéolos Pulmonares/citologia , Proteínas Associadas a Surfactantes Pulmonares , Animais , Apoproteínas/efeitos dos fármacos , Apoproteínas/genética , Aquaporina 5 , Polaridade Celular , Células Cultivadas , Células Epiteliais/classificação , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Fator 10 de Crescimento de Fibroblastos , Fator 7 de Crescimento de Fibroblastos , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/genética , Canais Iônicos/análise , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/genética , Masculino , Fenótipo , Biossíntese de Proteínas/efeitos dos fármacos , Biossíntese de Proteínas/genética , Alvéolos Pulmonares/efeitos dos fármacos , Surfactantes Pulmonares/efeitos dos fármacos , Surfactantes Pulmonares/genética , RNA Mensageiro/análise , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
17.
Am J Physiol ; 273(5): C1549-61, 1997 11.
Artigo em Inglês | MEDLINE | ID: mdl-9374640

RESUMO

The molecular pathways for fluid transport in pulmonary, oral, and nasal tissues are still unresolved. Here we use immunocytochemistry and immunoelectron microscopy to define the sites of expression of four aquaporins in the respiratory tract and glandular epithelia, where they reside in distinct, nonoverlapping sites. Aquaporin-1 (AQP1) is present in apical and basolateral membranes of bronchial, tracheal, and nasopharyngeal vascular endothelium and fibroblasts. AQP5 is localized to the apical plasma membrane of type I pneumocytes and the apical plasma membranes of secretory epithelium in upper airway and salivary glands. In contrast, AQP3 is present in basal cells of tracheal and nasopharyngeal epithelium and is abundant in basolateral membranes of surface epithelial cells of nasal conchus. AQP4 resides in basolateral membranes of columnar cells of bronchial, tracheal, and nasopharyngeal epithelium; in nasal conchus AQP4 is restricted to basolateral membranes of a subset of intra- and subepithelial glands. These sites of expression suggest that transalveolar water movement, modulation of airway surface liquid, air humidification, and generation of nasopharyngeal secretions involve a coordinated network of aquaporin water channels.


Assuntos
Aquaporinas , Canais Iônicos/análise , Proteínas de Membrana , Sistema Respiratório/citologia , Glândulas Salivares/citologia , Sequência de Aminoácidos , Animais , Anticorpos , Aquaporina 1 , Aquaporina 3 , Aquaporina 4 , Aquaporina 5 , Membrana Celular/ultraestrutura , Imuno-Histoquímica , Masculino , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Mucosa/citologia , Mucosa Nasal/citologia , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/química , Ratos , Ratos Wistar , Frações Subcelulares/ultraestrutura
18.
Am J Physiol ; 273(5): C1541-8, 1997 11.
Artigo em Inglês | MEDLINE | ID: mdl-9374639

RESUMO

Developmental expression of aquaporin water transport proteins is not well understood in respiratory tract or secretory glands; here we define aquaporin protein ontogeny in rat. Expression of aquaporin-3 (AQP3), AQP4, and AQP5 proteins occurs within 2 wk after birth, whereas AQP1 first appears before birth. In most tissues, aquaporin protein expression increases progressively, although transient high-level expression is noted in distal lung (AQP4 at postnatal day +2) and trachea (AQP5 at postnatal day +21 and AQP3 at postnatal day +42). In mature animals, AQP5 is abundant in distal lung and salivary glands, AQP3 and AQP4 are present in trachea, and AQP1 is present in all of these tissues except salivary glands. Surprisingly, all four aquaporin proteins are highly abundant in nasopharynx. Unlike AQP1, corticosteroids did not induce expression of AQP3, AQP4, or AQP5 in lung. Our results seemingly implicate aquaporins in proximal airway humidification, glandular secretion, and perinatal clearance of fluid from distal airways. However, the studies underscore a need for detailed immunohistochemical characterizations and definitive functional studies.


Assuntos
Envelhecimento/metabolismo , Aquaporinas , Regulação da Expressão Gênica no Desenvolvimento , Canais Iônicos/biossíntese , Pulmão/fisiologia , Proteínas de Membrana , Fenômenos Fisiológicos Respiratórios , Glândulas Salivares/fisiologia , Corticosteroides/farmacologia , Sequência de Aminoácidos , Animais , Anticorpos , Aquaporina 1 , Aquaporina 3 , Aquaporina 4 , Aquaporina 5 , Betametasona/farmacologia , Desenvolvimento Embrionário e Fetal , Olho/embriologia , Olho/crescimento & desenvolvimento , Olho/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Pulmão/embriologia , Pulmão/crescimento & desenvolvimento , Dados de Sequência Molecular , Especificidade de Órgãos , Fragmentos de Peptídeos , Ratos , Sistema Respiratório/embriologia , Sistema Respiratório/crescimento & desenvolvimento , Glândulas Salivares/embriologia , Glândulas Salivares/crescimento & desenvolvimento
19.
Am J Physiol ; 273(5): C1562-70, 1997 11.
Artigo em Inglês | MEDLINE | ID: mdl-9374641

RESUMO

The aquaporin-1 (AQP1) water channel protein is expressed in multiple mammalian tissues by several different developmental programs; however, the genetic regulation is undefined. The proximal promoter of mouse Aqp1 contains multiple putative cis-acting regulatory elements, and mouse erythroleukemia (MEL) cells are a well-characterized model for erythroid differentiation. Corticosteroid or dimethyl sulfoxide (DMSO) exposure induces AQP1 protein expression in MEL cells, and transcriptional regulation was investigated by transient transfections with Aqp1 promoter-reporter constructs. Dexamethasone induction is abrogated by deletion of two glucocorticoid response elements -0.5 kilobases (kb) from the transcription initiation site. Mutation of the GATA element at -0.62 kb has no effect, whereas mutation of the CACCC site at -37 bp significantly reduces DMSO-induced promoter activity. Hydroxyurea induces expression of AQP1 protein without acting through the proximal promoter. The MEL cell line is a reproducible erythroid model system for studying transcriptional regulation of the Aqp1 gene while determining the consequences on AQP1 protein biosynthesis.


Assuntos
Aquaporinas , Dexametasona/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Canais Iônicos/biossíntese , Animais , Aquaporina 1 , Cloranfenicol O-Acetiltransferase/biossíntese , Dimetil Sulfóxido/farmacologia , Éxons , Regulação Neoplásica da Expressão Gênica/genética , Genes , Genes Reporter , Glucocorticoides/farmacologia , Leucemia Eritroblástica Aguda , Camundongos , Regiões Promotoras Genéticas/efeitos dos fármacos , RNA Mensageiro/biossíntese , Proteínas Recombinantes de Fusão/biossíntese , Mapeamento por Restrição , Deleção de Sequência , Transcrição Gênica/efeitos dos fármacos , Transfecção , Células Tumorais Cultivadas
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