1
|
Kerschner JL, Paranjapye A, Schacht M, Meckler F, Huang F, Bebek G, Van Wettere AJ, Regouski M, Perisse IV, White KL, Polejaeva IA, Leir SH, Harris A. Transcriptomic analysis of lung development in wildtype and CFTR -/- sheep suggests an early inflammatory signature in the CF distal lung. Funct Integr Genomics 2023; 23:135. [PMID: 37085733 PMCID: PMC10121546 DOI: 10.1007/s10142-023-01050-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/22/2023] [Accepted: 04/03/2023] [Indexed: 04/23/2023]
Abstract
The precise molecular events initiating human lung disease are often poorly characterized. Investigating prenatal events that may underlie lung disease in later life is challenging in man, but insights from the well-characterized sheep model of lung development are valuable. Here, we determine the transcriptomic signature of lung development in wild-type sheep (WT) and use a sheep model of cystic fibrosis (CF) to characterize disease associated changes in gene expression through the pseudoglandular, canalicular, saccular, and alveolar stages of lung growth and differentiation. Using gene ontology process enrichment analysis of differentially expressed genes at each developmental time point, we define changes in biological processes (BP) in proximal and distal lung from WT or CF animals. We also compare divergent BP in WT and CF animals at each time point. Next, we establish the developmental profile of key genes encoding components of ion transport and innate immunity that are pivotal in CF lung disease and validate transcriptomic data by RT-qPCR. Consistent with the known pro-inflammatory phenotype of the CF lung after birth, we observe upregulation of inflammatory response processes in the CF sheep distal lung during the saccular stage of prenatal development. These data suggest early commencement of therapeutic regimens may be beneficial.
Collapse
Affiliation(s)
- Jenny L Kerschner
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Alekh Paranjapye
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Makayla Schacht
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Frederick Meckler
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Felix Huang
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Gurkan Bebek
- Center for Proteomics and Bioinformatics, Cleveland, OH, USA
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Arnaud J Van Wettere
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UH, USA
| | - Misha Regouski
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UH, USA
| | - Iuri Viotti Perisse
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UH, USA
| | - Kenneth L White
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UH, USA
| | - Irina A Polejaeva
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UH, USA
| | - Shih-Hsing Leir
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, Cleveland, OH, USA.
| |
Collapse
|
2
|
Leir SH, Yin S, Kerschner JL, Cosme W, Harris A. An atlas of human proximal epididymis reveals cell-specific functions and distinct roles for CFTR. Life Sci Alliance 2020; 3:e202000744. [PMID: 32855272 PMCID: PMC7471510 DOI: 10.26508/lsa.202000744] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022] Open
Abstract
Spermatozoa released from the testis are unable to fertilize an egg without a coordinated process of maturation in the lumen of the epididymis. Relatively little is known about the molecular events that integrate this critical progression along the male genital ducts in man. Here, we use single cell RNA-sequencing to construct an atlas of the human proximal epididymis. We find that the CFTR, which is pivotal in normal epididymis fluid transport, is most abundant in surface epithelial cells in the efferent ducts and in rare clear cells in the caput epididymis, suggesting region-specific functional properties. We reveal transcriptional signatures for multiple cell clusters, which identify the individual roles of principal, apical, narrow, basal, clear, halo, and stromal cells in the epididymis. A marked cell type-specific distribution of function is seen along the duct with local specialization of individual cell types integrating processes of sperm maturation.
Collapse
Affiliation(s)
- Shih-Hsing Leir
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, and Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Shiyi Yin
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, and Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Jenny L Kerschner
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, and Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Wilmel Cosme
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, and Case Comprehensive Cancer Center, Cleveland, OH, USA
| | - Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University School of Medicine, and Case Comprehensive Cancer Center, Cleveland, OH, USA
| |
Collapse
|
3
|
Sharma S, Kumaran GK, Hanukoglu I. High-resolution imaging of the actin cytoskeleton and epithelial sodium channel, CFTR, and aquaporin-9 localization in the vas deferens. Mol Reprod Dev 2020; 87:305-319. [PMID: 31950584 DOI: 10.1002/mrd.23317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/05/2020] [Indexed: 12/30/2022]
Abstract
Vas deferens is a conduit for sperm and fluid from the epididymis to the urethra. The duct is surrounded by a thick smooth muscle layer. To map the actin cytoskeleton of the duct and its epithelium, we reacted sections of the proximal and distal regions with fluorescent phalloidin. Confocal microscopic imaging showed that the cylinder-shaped epithelium of the proximal region has a thick apical border of actin filaments that form microvilli. The epithelium of the distal region is covered with tall stereocilia (13-18 µm) that extend from the apical border into the lumen. In both regions, the lateral and basal cell borders showed a thin lining of actin cytoskeleton. The vas deferens epithelium contains various channels to regulate the fluid composition in the lumen. We mapped the localization of the epithelial sodium channel (ENaC), aquaporin-9 (AQP9), and cystic fibrosis transmembrane conductance regulator (CFTR) in the rat and mouse vas deferens. ENaC and AQP9 immunofluorescence were localized on the luminal surface and stereocilia and also in the basal and smooth muscle layers. CFTR immunofluorescence appeared only on the luminal surface and in smooth muscle layers. The localization of all three channels on the apical surface of the columnar epithelial cells provides clear evidence that these channels are involved concurrently in the regulation of fluid and electrolyte balance in the lumen of the vas deferens. ENaC allows the flow of Na+ ions from the lumen into the cytoplasm, and the osmotic gradient generated provides the driving force for the passive flow of water through AQP channels.
Collapse
Affiliation(s)
- Sachin Sharma
- Laboratory of Cell Biology, Ariel University, Ariel, Israel
| | | | | |
Collapse
|
4
|
Sharma S, Hanukoglu I. Mapping the sites of localization of epithelial sodium channel (ENaC) and CFTR in segments of the mammalian epididymis. J Mol Histol 2019; 50:141-154. [PMID: 30659401 DOI: 10.1007/s10735-019-09813-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 01/14/2019] [Indexed: 01/17/2023]
Abstract
The sperm produced in the seminiferous tubules pass through the rete testis, efferent ducts, and epididymis. The epididymis has three distinct regions known as caput, corpus, and cauda. The transit through the epididymis is an essential process in sperm maturation. The lumen of each epididymal region has a unique fluid composition regulated by many ion channels and transporters in the epithelial cells. The objective of this study was to map the sites of localization of ion channels ENaC and CFTR along the length of the mouse and rat epididymis using confocal microscopic imaging. The integrity of the fine structure of the tissues was verified by fluorescent phalloidin staining of actin filaments visualized by high-resolution confocal microscopy. The 2D and 3D images showed preservation of the stereocilia. Based on these images we determined morphometric parameters of the epithelial cells and ducts. ENaC and CFTR immunofluorescence appeared almost continuously on the apical membrane of caput and in smooth muscle myoid cells. In cauda, CFTR expression was observed continuously in long stretches of epithelium interrupted by clusters of cells that showed no CFTR expression. Similar patterns of localization were observed in both mouse and rat samples. Mutations in the CFTR gene are known to result in male infertility. Based on the widespread presence of ENaC along the epididymis we suggest that mutations in ENaC subunits may also be associated with male infertility. The diverse phenotypes associated with CFTR mutations may be due to malfunction of CFTR at specific subcellular locations in the male reproductive system.
Collapse
Affiliation(s)
- Sachin Sharma
- Laboratory of Cell Biology, Ariel University, 40700, Ariel, Israel
| | - Israel Hanukoglu
- Laboratory of Cell Biology, Ariel University, 40700, Ariel, Israel.
| |
Collapse
|
5
|
Khadijah Ramli NS, Giribabu N, Salleh N. Testosterone enhances expression and functional activity of epithelial sodium channel (ENaC), cystic fibrosis transmembrane regulator (CFTR) and sodium hydrogen exchanger (NHE) in vas deferens of sex-steroid deficient male rats. Steroids 2018; 138:117-133. [PMID: 30003911 DOI: 10.1016/j.steroids.2018.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 12/19/2022]
Abstract
UNLABELLED Effects of testosterone on expression and functional activity of ENaC, CFTR and NHE in vas deferens were investigated. METHODS Orchidectomized, adult male rats were given 125 and 250 μg/kg/day testosterone subcutaneously, with or without flutamide and finasteride for seven consecutive days. At the end of the treatment, rats were anesthetized and vas deferens were perfused. Changes in vas deferens fluid secretion rate, pH, HCO3-, Cl- and Na+ concentrations were recorded in the presence of amiloride and Cftr inh-172. Rats were then sacrificed and vas deferens were harvested and subjected for molecular biological analysis. RESULTS Testosterone treatment caused the fluid pH and HCO3- concentrations to decrease but secretion rate, Cl- and Na+ concentrations to increase, where upon amiloride administration, the pH and HCO3- concentration increased but Cl- and Na+ concentrations further increased. In testosterone-treated rats, administration of Cftr inh-172 caused all fluid parameters to decrease. In testosterone-treated rats co-administered with flutamide or finasteride, pH and HCO3- concentration increased but fluid secretion rate, Cl- and Na+ concentrations decreased and these parameters were not affected by amiloride or Cftr inh-172 administration. Under testosterone influence, CFTR and γ-ENaC were highly expressed at the apical membrane while NHE-1 and 4 were highly expressed at the basolateral membrane of vas deferens epithelium. Meanwhile, NHE-2 and 3 were highly expressed at the apical membrane. CONCLUSIONS Differential expression of ENaC, CFTR and NHE in vas deferens under testosterone influence indicated the important role of these transporters in creating optimal fluid microenvironment that is essential for preserving male fertility.
Collapse
Affiliation(s)
| | - Nelli Giribabu
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Naguib Salleh
- Department of Physiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| |
Collapse
|
6
|
Anbalagan S, Pires IM, Blick C, Hill MA, Ferguson DJP, Chan DA, Hammond EM. Radiosensitization of renal cell carcinoma in vitro through the induction of autophagy. Radiother Oncol 2012; 103:388-93. [PMID: 22551566 DOI: 10.1016/j.radonc.2012.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 04/02/2012] [Accepted: 04/02/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND PURPOSE For patients diagnosed with advanced renal cell carcinoma (RCC), there are few therapeutic options. Radiation therapy is predominantly used to treat metastasis and has not proven effective in the adjuvant setting for renal cancer. Furthermore, RCC is resistant to standard cytotoxic chemotherapies. Targeted anti-angiogenics are the standard of care for RCC but are not curative. Newer agents, such as mTOR inhibitors and others that induce autophagy, have shown great promise for treating RCC. Here, we investigate the potential use of the small molecule STF-62247 to modulate radiation. MATERIALS AND METHODS Using RCC cell lines, we evaluate sensitivity to radiation in addition to agents that induce autophagic cell death by clonogenic survival assays. Furthermore, these were also tested under physiological oxygen levels. RESULTS STF-62247 specifically induces autophagic cell death in cells that have lost VHL, an essential mutation in the development of RCC. Treatment with STF-62247 did not alter cell cycle progression but when combined with radiation increased cell killing under oxic and hypoxic/physiological conditions. CONCLUSIONS This study highlights the possibility of combining targeted therapeutics such as STF-62247 or temsirolimus with radiation to reduce the reliance on partial or full nephrectomy and improve patient prognosis.
Collapse
Affiliation(s)
- Selvakumar Anbalagan
- The Cancer Research UK/MRC Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, UK
| | | | | | | | | | | | | |
Collapse
|
7
|
Bertog M, Cuffe JE, Pradervand S, Hummler E, Hartner A, Porst M, Hilgers KF, Rossier BC, Korbmacher C. Aldosterone responsiveness of the epithelial sodium channel (ENaC) in colon is increased in a mouse model for Liddle's syndrome. J Physiol 2007; 586:459-75. [PMID: 18006588 DOI: 10.1113/jphysiol.2007.140459] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Liddle's syndrome is an autosomal dominant form of human hypertension, caused by gain-of-function mutations of the epithelial sodium channel (ENaC) which is expressed in aldosterone target tissues including the distal colon. We used a mouse model for Liddle's syndrome to investigate ENaC-mediated Na+ transport in late distal colon by measuring the amiloride-sensitive transepithelial short circuit current (Delta I SC-Ami) ex vivo. In Liddle mice maintained on a standard salt diet, Delta I SC-Ami was only slightly increased but plasma aldosterone (P Aldo) was severely suppressed. Liddle mice responded to a low or a high salt diet by increasing or decreasing, respectively, their P Aldo and Delta I SC-Ami. However, less aldosterone was required in Liddle animals to achieve similar or even higher Na+ transport rates than wild-type animals. Indeed, the ability of aldosterone to stimulate Delta I SC-Ami was about threefold higher in Liddle animals than in the wild-type controls. Application of aldosterone to colon tissue in vitro confirmed that ENaC stimulation by aldosterone was not only preserved but enhanced in Liddle mice. Aldosterone-induced transcriptional up-regulation of the channel's beta- and gamma-subunit (beta ENaC and gamma ENaC) and of the serum- and glucocorticoid-inducible kinase 1 (SGK1) was similar in colon tissue from Liddle and wild-type animals, while aldosterone had no transcriptional effect on the alpha-subunit (alpha ENaC). Moreover, Na+ feedback regulation was largely preserved in colon tissue of Liddle animals. In conclusion, we have demonstrated that in the colon of Liddle mice, ENaC-mediated Na+ transport is enhanced with an increased responsiveness to aldosterone. This may be pathophysiologically relevant in patients with Liddle's syndrome, in particular on a high salt diet, when suppression of P Aldo is likely to be insufficient to reduce Na+ absorption to an appropriate level.
Collapse
Affiliation(s)
- Marko Bertog
- Institut für Zelluläre und Molekulare Physiologie, Waldstr. 6, 91054 Erlangen, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Su X, Li Q, Shrestha K, Cormet-Boyaka E, Chen L, Smith PR, Sorscher EJ, Benos DJ, Matalon S, Ji HL. Interregulation of proton-gated Na(+) channel 3 and cystic fibrosis transmembrane conductance regulator. J Biol Chem 2006; 281:36960-8. [PMID: 17012229 DOI: 10.1074/jbc.m608002200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proton-gated Na(+) channels (ASIC) are new members of the epithelial sodium channel/degenerin gene family. ASIC3 mRNA has been detected in the homogenate of pulmonary tissues. However, whether ASIC3 is expressed in the apical membranes of lung epithelial cells and whether it regulates cystic fibrosis transmembrane conductance regulator (CFTR) function are not known at the present time. Using reverse transcription-PCR, we found that the ASIC3 mRNA was expressed in the human airway mucosal gland (Calu-3) and human airway epithelial (16HBE14o) cells. Indirect immunofluorescence microscopy revealed that ASIC3 was co-segregated with CFTR in the apical membranes of Calu-3 cells. Proton-gated, amiloride-sensitive short circuit Na(+) currents were recorded across Calu-3 monolayers mounted in an Ussing chamber. In whole-cell patch clamp studies, activation of CFTR channels with cAMP reduced proton-gated Na(+) current in Calu-3 cells from -154 +/- 28 to -33 +/- 16 pA (n = 5, p < 0.05) at -100 mV. On the other hand, cAMP-activated CFTR activity was significantly inhibited following constitutive activation of putative ASIC3 at pH 6.0. Immunoassays showed that both ASIC3 and CFTR proteins were expressed and co-immunoprecipitated mutually in Calu-3 cells. Similar results were obtained in human embryonic kidney 293T cells following transient co-transfection of ASIC3 and CFTR. Our results indicate that putative CFTR and ASIC3 channels functionally interact with each other, possibly via an intermolecular association. Because acidic luminal fluid in the cystic fibrosis airway and lung tends to stimulate ASIC3 channel expression and activity, the interaction of ASIC3 and CFTR may contribute to defective salt and fluid transepithelial transport in the cystic fibrotic pulmonary system.
Collapse
Affiliation(s)
- Xuefeng Su
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Carlin RW, Sedlacek RL, Quesnell RR, Pierucci-Alves F, Grieger DM, Schultz BD. PVD9902, a porcine vas deferens epithelial cell line that exhibits neurotransmitter-stimulated anion secretion and expresses numerous HCO3(-) transporters. Am J Physiol Cell Physiol 2006; 290:C1560-71. [PMID: 16421205 DOI: 10.1152/ajpcell.00468.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epithelial ion transport disorders, including cystic fibrosis, adversely affect male reproductive function by nonobstructive mechanisms and by obstruction of the distal duct. Continuous cell lines that could be used to define ion transport mechanisms in this tissue are not readily available. In the present study, porcine vas deferens epithelial cells were isolated by standard techniques, and the cells spontaneously immortalized to form a porcine vas deferens epithelial cell line that we have titled PVD9902. Cells were maintained in continuous culture for >4 yr and 200 passages in a typical growth medium. Frozen stocks were generated, and thawed cells exhibited growth characteristics indistinguishable from their nonfrozen counterparts. Molecular and immunocytochemical studies confirmed the origin and epithelial nature of these cells. When seeded on permeable supports, PVD9902 cells grew as electrically tight (>6,000 ohms x cm2), confluent monolayers that responded to forskolin with an increase in short-circuit current (I(sc); 8 +/- 1 microA/cm2) that required Cl-, HCO3(-), and Na+, and was partially sensitive to bumetanide. mRNA was expressed for a number of anion transporters, including CFTR, electrogenic Na+-HCO3(-) cotransporter 1b (NBCe1b), downregulated in adenoma, pendrin, and Cl-/formate exchanger. Both forskolin and isoproterenol caused an increase in cellular cAMP levels. In addition, PVD9902 cell monolayers responded to physiological (i.e., adenosine, norepinephrine) and pharmacological [i.e., 5'-(N-ethylcarboxamido)adenosine, isoproterenol] agonists with increases in I(sc). Unlike their freshly isolated counterparts, however, PVD9902 cells did not respond to glucocorticoid exposure with an increase in amiloride-sensitive I(sc). RT-PCR analysis revealed the presence of both glucocorticoid and mineralocorticoid receptor mRNA as well as mRNA for the alpha- and gamma-subunits of the epithelia Na+ channels (alpha- and gamma-ENaC), but not beta-ENaC. Nonetheless, PVD9902 cells recapitulated most observations in freshly isolated cells and thus represent a powerful new tool to characterize mechanisms that contribute to male reproductive function.
Collapse
Affiliation(s)
- Ryan W Carlin
- Dept. of Anatomy and Physiology, Kansas State Univ., 1600 Denison Ave., Manhattan, KS 66506, USA
| | | | | | | | | | | |
Collapse
|
10
|
Perreault ML, Rollo CD. Transgenic growth hormone mice exposed to lifetime constant illumination: gender-specific effects. CAN J ZOOL 2004. [DOI: 10.1139/z04-071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Photoperiod affects most of the features altered in transgenic growth hormone (TG) mice, and laboratory rats and mice retain some sensitivity to photoperiod. We examined growth, feeding, longevity, and reproduction of TG mice and normal control mice (Mus musculus L., 1758) in 12 h light : 12 h dark (LD) and 24 h light (LL) photoperiods. Sexual dichotomy in growth and hepatic gene expression are considered to require gender-specific patterns of growth hormone secretion that are absent in TG mice. Regardless, in the LD photoperiod mature TG females were 82.8% (46.8 g) of the mass of TG males (56.5 g, p < 0.05), whereas control mice showed no size dichotomy (≈33 g). Mature masses of TG males and of control mice of either gender were unaffected by the LL photoperiod. TG females, however, reached a mature mass 92% (50.9 g) of that of mature TG males in the LL photoperiod, attenuating the sexual size dichotomy expressed in the LD photoperiod. Growth of females was slower than that of males, even in the control group. TG females in the LL photoperiod expressed faster growth, higher reproduction, and greater mean longevity than TG females in the LD photoperiod. Differences in age-related feeding associated with gender and photoperiod reflected differential growth rates. Females grew more slowly and ate more than males of similar age because they were smaller (i.e., had lower growth efficiencies). The LL photoperiod improved the energy balance of TG females. Possible mechanisms mediating such gender-specific effects are explored.
Collapse
|
11
|
Ji HL, Benos DJ. Degenerin sites mediate proton activation of deltabetagamma-epithelial sodium channel. J Biol Chem 2004; 279:26939-47. [PMID: 15084585 DOI: 10.1074/jbc.m401143200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The delta-subunit of epithelial Na(+) channels (ENaC) is predominately expressed in brain, heart, and pancreas. The amiloride sensitivity, Na(+) conductance, and critical domains for gating are characterized as a cross between proton-activated Na(+) channels and alpha-ENaC. The hypothesis that external protons may activate human delta-ENaC was addressed by expressing deltabetagamma-hENaC in Xenopus oocytes and evaluating proton-activated current with the two-electrode voltage clamp technique. Our results showed that protons transiently evoked a Na(+) current with an EC(50) of pH 6 overlapped on the basal current of deltabetagamma-hENaC. Proton-activated current was not observed in uninjected oocytes. Studies on gating kinetics revealed that activation, desensitization, and recovery times of proton-activated Na(+) current were 3.8 +/- 0.5 s, 253 +/- 9.5 s, and 10 +/- 3.6 s, respectively (n = 4-12). Alkali metal cation selectivity of the proton-activated current was identical to that of the basal current of deltabetagamma-hENaC. The metabolic acids, lactate, pyruvate, and formate, modified the proton-activated current, as did hypo-osmotic stress. EDTA, hypo-osmolarity, and lactate enhanced proton activation synergistically. Our results suggest that delta-hENaC subunit is essential for proton-activated current and gamma-subunit may potentially regulate the response of delta-hENaC to protons. We have concluded that deltabetagamma-hENaC is a proton-activated cation channel whose closing gate can be regulated by a proton-induced conformational change. Proton-sensitivity of deltabetagamma-hENaC may be an important mechanism for integrating external ischemic signals in inflamed and hypoxic tissues.
Collapse
Affiliation(s)
- Hong-Long Ji
- Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA.
| | | |
Collapse
|
12
|
Williams SH, Sahota V, Palmai-Pallag T, Tebbutt SJ, Walker J, Harris A. Evaluation of gene targeting by homologous recombination in ovine somatic cells. Mol Reprod Dev 2003; 66:115-25. [PMID: 12950098 DOI: 10.1002/mrd.10340] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mouse models for some human genetic diseases are limited in their applications since they do not accurately reproduce the phenotype of the human disease. It has been suggested that larger animals, for example sheep, might produce more useful models, as some aspects of sheep physiology and anatomy are more similar to those of humans. The development of methods to clone animals from somatic cells provides a potential novel route to generate such large animal models following gene targeting. Here, we assess targeting of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in ovine somatic cells using homologous recombination (HR) of targeting constructs with extensive (>11 kb) homology. Electroporation of these constructs into ovine fetal and post-natal fibroblasts generated G418-resistant clones, but none analyzed had undergone HR, suggesting that at least for this locus, it is an extremely inefficient process. Karyotyping of targeted ovine fetal fibroblasts showed them to be less chromosomally stable than post-natal fibroblasts, and, moreover, extended culture periods caused them to senesce, adversely affecting their viability for use as nuclear transfer donor cells. These data stress the importance of donor cell choice in somatic cell cloning and suggest that culture time be kept to a minimum prior to nuclear transfer in order to maximize cell viability.
Collapse
Affiliation(s)
- Sarah H Williams
- Paediatric Molecular Genetics, Weatherall Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom
| | | | | | | | | | | |
Collapse
|
13
|
Carlin RW, Lee JH, Marcus DC, Schultz BD. Adenosine stimulates anion secretion across cultured and native adult human vas deferens epithelia. Biol Reprod 2003; 68:1027-34. [PMID: 12604657 DOI: 10.1095/biolreprod.102.009381] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Experiments were conducted to determine the responsiveness of human vas deferens epithelial cell monolayers to adenosine and related agonists. Human abdominal vas deferens epithelial cells have been isolated from adult tissues and grown to confluence on permeable supports. All cells exhibit intense ZO-1 and cytokeratin immunoreactivity. Cultured cell monolayers exhibit high electrical resistance with a lumen-negative potential difference and short circuit current (I(sc)) indicative of anion secretion and/or cation absorption. A portion of the basal I(sc) is inhibited by amiloride. Amiloride-sensitive I(sc) is enhanced by exposure to glucocorticoids and is Na(+) dependent, indicating the presence of epithelial sodium channel-mediated Na(+) absorption. Epithelial anion secretion and intracellular generation of cAMP are acutely stimulated by adenosine and the adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine (NECA), with these effects being fully blocked by 8-phenyltheophylline. Adenosine receptors are localized to the apical membrane of the epithelial cells, as basolateral adenosine is without effect. Freshly excised human vas deferens recapitulate observations made on cultured epithelia when evaluated with the self-referencing vibrating probe: amiloride inhibition of basal ion transport, stimulation by adenosine, and inhibition by 8-phenyltheophyline. These results demonstrate that adult human vas deferens epithelium actively transports ions to generate the luminal environment of the deferent duct. Thus, vas deferens epithelium likely plays an active role in male fertility, and interventions that modulate epithelial function might be exploited to treat male-factor infertility or in contraception.
Collapse
Affiliation(s)
- Ryan W Carlin
- Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66502-5802, USA
| | | | | | | |
Collapse
|
14
|
Carlin RW, Quesnell RR, Zheng L, Mitchell KE, Schultz BD. Functional and molecular evidence for Na(+)-HCO cotransporter in porcine vas deferens epithelia. Am J Physiol Cell Physiol 2002; 283:C1033-44. [PMID: 12225967 DOI: 10.1152/ajpcell.00493.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study focused on the role of sodium-bicarbonate cotransporter (NBC1) in cAMP-stimulated ion transport in porcine vas deferens epithelium. Ion substitution experiments in modified Ussing chambers revealed that cAMP-mediated stimulation was dependent on the presence of Na(+), HCO, and Cl(-) for a full response. HCO-dependent current was unaffected by acetazolamide, bumetanide, or amiloride but was inhibited by basolateral 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Na(+)-driven, HCO-dependent, stilbene-inhibitable anion flux was observed across the basolateral membrane of selectively permeabilized monolayers. Results of radiotracer flux studies suggest a 4,4'-dinitrostilbene-2,2'-disulfonate-sensitive stoichiometry of 2 base equivalents per Na(+). Antibodies raised against rat kidney NBC epitopes (rkNBC; amino acids 338-391 and 928-1035) identified a single band of ~145 kDa. RT-PCR detected NBC1 message in porcine vas deferens epithelia. These results demonstrate that vas deferens epithelial cells possess the proteins necessary for the vectoral transport of HCO and that these mechanisms are maintained in primary culture. Taken together, the results indicate that vas deferens epithelia play an active role in male fertility and have implications for our understanding of the relationship between cystic fibrosis and congenital bilateral absence of the vas deferens.
Collapse
Affiliation(s)
- Ryan W Carlin
- Department of Anatomy and Physiology, Kansas State University, 1600 Denison Avenue, VMS 228, Manhattan, KS 66506, USA
| | | | | | | | | |
Collapse
|
15
|
Phillips ML, Schultz BD. Steroids modulate transepithelial resistance and Na(+) absorption across cultured porcine vas deferens epithelia. Biol Reprod 2002; 66:1016-23. [PMID: 11906921 DOI: 10.1095/biolreprod66.4.1016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Epithelial cells were isolated from adult porcine vas deferens and grown in the absence or presence of steroid hormones. Transepithelial resistance (R(te)), basal short circuit current (I(sc)), and the effects of selected ion transport modulators on these parameters were evaluated in modified Ussing chambers at three time points (5-8, 11-14, and 18-22 days postseeding). At the earliest time point, no significant differences were observed. At the middle time point, when compared with R(te) in untreated control monolayers, R(te) in monolayers exposed to 17beta-estradiol, aldosterone, cortisol, cortisone, prednisolone, prednisone, and dexamethasone was significantly lower; in contrast, R(te) in monolayers exposed to testosterone, dihydrotestosterone, or progesterone did not differ from that in control monolayers. Treatments with cortisol, prednisolone, and dexamethasone were associated with an elevated basal I(sc) that was amiloride sensitive, indicating ongoing Na(+) absorption by these monolayers. R(te) was increased by amiloride treatment in glucocorticoid-treated monolayers but remained significantly less than that of control monolayers. At the third time point, the postamiloride R(te) of glucocorticoid-treated monolayers was not different from that of control monolayers. Responses to ATP, forskolin, bumetanide, and DASU-02 were not affected by steroid treatment at any time point. Taken together, these results suggest that estrogens and corticosteroids can modulate epithelial function in the distal excurrent duct of the adult male reproductive system. At physiological or pharmacological concentrations, these hormones would be expected to modify the luminal environment (both the ionic composition and pH) to which sperm are exposed and thus affect male fertility.
Collapse
Affiliation(s)
- Maureen L Phillips
- Department of Anatomy and Physiology, Kansas State University, 1600 Denison Avenue, Manhattan, KS 66506, USA
| | | |
Collapse
|
16
|
Sedlacek RL, Carlin RW, Singh AK, Schultz BD. Neurotransmitter-stimulated ion transport by cultured porcine vas deferens epithelium. Am J Physiol Renal Physiol 2001; 281:F557-70. [PMID: 11502604 DOI: 10.1152/ajprenal.2001.281.3.f557] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A collagenase-based dissociation technique has been developed to routinely establish monolayer cultures of freshly isolated porcine vas deferens epithelium. Cells isolated from each tissue are transferred to 25-cm(2) tissue culture flasks and grown in a standard cell culture medium. Flasks reach confluency in 3-4 days, and cells are subsequently seeded onto permeable supports. Cultured cells display a monolayer cobblestone appearance and are immunoreactive to anti-ZO-1 and anti-cytokeratin antibodies. Electron microscopy is employed to demonstrate the presence of junctional complexes and microvilli. When evaluated in modified Ussing chambers, cultured monolayers exhibit a basal lumen negative potential difference, high electrical resistance (>1,000 Omega. cm(2)), and respond to norepinephrine, vasopressin, ATP, adenosine, and histamine, with changes in short-circuit current indicative of anion secretion. Responses are significantly attenuated in Cl(-)- and/or HCO-free solutions. Attempts to further optimize culture conditions have shown that chronic exposure to insulin increases proliferation rates. Thus the culture method described will reliably produce viable neurotransmitter-responsive cell monolayers that will allow for the characterization of vas deferens epithelial function and associated control mechanisms.
Collapse
Affiliation(s)
- R L Sedlacek
- Department of Anatomy and Physiology, Kansas State University, 1600 Denison Ave., Manhattan, KS 66506, USA
| | | | | | | |
Collapse
|