The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Melissa H. Little - One of the best experts on this subject based on the ideXlab platform.
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Single-Cell analysis reveals congruence between kidney organoids and human fetal kidney
Genome Medicine, 2019Co-Authors: Alexander N. Combes, Pei X. Er, L. Zappia, Alicia Oshlack, Melissa H. LittleAbstract:Background Human kidney organoids hold promise for studying development, disease modelling and drug screening. However, the utility of stem Cell-derived kidney tissues will depend on how faithfully these replicate normal fetal development at the level of Cellular identity and complexity. Methods Here, we present an integrated analysis of single Cell datasets from human kidney organoids and human fetal kidney to assess similarities and differences between the component Cell types. Results Clusters in the combined dataset contained Cells from both organoid and fetal kidney with transcriptional congruence for key stromal, endothelial and Nephron Cell type-specific markers. Organoid enriched neural, glial and muscle progenitor populations were also evident. Major transcriptional differences between organoid and human tissue were likely related to technical artefacts. Cell type-specific comparisons revealed differences in stromal, endothelial and Nephron progenitor Cell types including expression of WNT2B in the human fetal kidney stroma. Conclusions This study supports the fidelity of kidney organoids as models of the developing kidney and affirms their potential in disease modelling and drug screening.
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Single-Cell analysis reveals congruence between kidney organoids and human fetal kidney
Genome medicine, 2019Co-Authors: Alexander N. Combes, L. Zappia, Alicia Oshlack, Melissa H. LittleAbstract:Human kidney organoids hold promise for studying development, disease modelling and drug screening. However, the utility of stem Cell-derived kidney tissues will depend on how faithfully these replicate normal fetal development at the level of Cellular identity and complexity. Here, we present an integrated analysis of single Cell datasets from human kidney organoids and human fetal kidney to assess similarities and differences between the component Cell types. Clusters in the combined dataset contained Cells from both organoid and fetal kidney with transcriptional congruence for key stromal, endothelial and Nephron Cell type-specific markers. Organoid enriched neural, glial and muscle progenitor populations were also evident. Major transcriptional differences between organoid and human tissue were likely related to technical artefacts. Cell type-specific comparisons revealed differences in stromal, endothelial and Nephron progenitor Cell types including expression of WNT2B in the human fetal kidney stroma. This study supports the fidelity of kidney organoids as models of the developing kidney and affirms their potential in disease modelling and drug screening.
Y Marunaka - One of the best experts on this subject based on the ideXlab platform.
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ADH action on whole-Cell currents by cytosolic Ca2+-dependent pathways in aldosterone-treated A6 Cells.
The Journal of membrane biology, 1996Co-Authors: T Nakahari, Y MarunakaAbstract:We studied the characteristics of the basal and antidiuretic hormone (arginine vasotocin, AVT)-activated whole Cell currents of an aldosterone-treated distal Nephron Cell line (A6) at two different cytosolic Ca2+ concentrations ([Ca2+] c , 2 and 30 nm). A6 Cells were cultured on a permeable support filter for 10 ∼ 14 days in media with supplemental aldosterone (1 μm). At 30 nm [Ca2+] c , basal conductances mainly consisted of Cl− conductances, which were sensitive to 5-nitro-2-(3-phenylpropylamino)-benzoate. Reduction of [Ca2+] c to 2 nm abolished the basal Cl− conductance. AVT evoked Cl− conductances at 2 as well as 30 nm [Ca2+] c . In addition to Cl− conductances, AVT induced benzamil-insensitive nonselective cation (NSC) conductances. This action on NSC conductances was observed at 30 nm [Ca2+] c but not at 2 nm [Ca2+] c . Thus, cytosolic Ca2+ regulates NSC and Cl− conductances in a distal Nephron Cell line (A6) in response to AVT. Keeping [Ca2+] c at an adequate level seems likely to be an important requirement for AVT regulation of ion conductances in aldosterone-treated A6 Cells.
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ADH-evoked [Cl-]i-dependent transient in whole Cell current of distal Nephron Cell line A6.
The American journal of physiology, 1995Co-Authors: T Nakahari, Y MarunakaAbstract:The effect of antidiuretic hormone (ADH) on a distal Nephron Cell line (A6) was studied using the whole Cell patch-clamp technique. A6 Cells were cultured on a permeable support filter for 10-14 days in media containing 10% fetal bovine serum without supplemental aldosterone. In the unstimulated condition A6 Cells had very small conductances of Na+,K+, and Cl-. Arginine vasotocin (AVT, 140 mU/ml, 280 nM) evoked a "transient" increase in whole Cell currents as did dibutyryl-adenosine 3',5'-cyclic monophosphate (5 mM). These transients consisted of two components; one was the nonselective cation conductance, and the other was the Cl- conductance. Activation of these conductances was dependent on intraCellular Cl- concentration ([Cl-]i). At low [Cl-]i (< or = 50 mM) both conductances were activated, whereas when [Cl-]i was 80 mM, only the Cl- conductance was activated. At high [Cl-]i (125 mM), both conductances were inhibited. It seems likely that the [Cl-]i maintained at a low level (< or = 50 mM) is an important requirement for A6 Cells to respond to AVT.
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Whole Cell conductance regulated by cytosolic [Cl-] and ADH-activated Cl- channels in a distal Nephron Cell line (A6).
Japanese Journal of Physiology, 1994Co-Authors: T Nakahari, Y MarunakaAbstract:The effect of antidiuretic hormone (ADH) on a distal Nephron Cell line (A6) was studied using the whole Cell patch clamp technique. Arginine vasotocin (AVT, 140mU/ml) evoked a "transient" increase in whole Cell currents as did dibutyryl cyclic AMP (5 mM). These transients consisted of two components: one was the non-selective cation conductance and the other was the Cl- conductance. The transient was evoked by AVT in the lower cytosolic Cl- concentration ([Cl-]i) (< approximately 50 mM), and was suppressed by higher concentrations of [Cl-]i (125 mM) in A6 Cells. It seems likely that the [Cl-]i maintained at a lower level is an important requirement for A6 Cells to respond to AVT.
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Insulin activates single amiloride-blockable Na channels in a distal Nephron Cell line (A6).
The American journal of physiology, 1992Co-Authors: Y Marunaka, N Hagiwara, H TohdaAbstract:Using the patch-clamp technique, we studied the effect of insulin on an amiloride-blockable Na channel in the apical membrane of a distal Nephron Cell line (A6) cultured on permeable collagen films for 10-14 days. NPo (N, number of channels per patch membrane; Po, average value of open probability of individual channels in the patch) under baseline conditions was 0.88 +/- 0.12 (SE)(n = 17). After making Cell-attached patches on the apical membrane which contained Na channels, insulin (1 mU/ml) was applied to the serosal bath. While maintaining the Cell-attached patch, NPo significantly increased to 1.48 +/- 0.19 (n = 17; P less than 0.001) after 5-10 min of insulin application. The open probability of Na channels was 0.39 +/- 0.01 (n = 38) under baseline condition, and increased to 0.66 +/- 0.03 (n = 38, P less than 0.001) after addition of insulin. The baseline single-channel conductance was 4pS, and neither the single-channel conductance nor the current-voltage relationship was significantly changed by insulin. These results indicate that insulin increases Na absorption in the distal Nephron by increasing the open probability of the amiloride-blockable Na channel.
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Cyclic GMP-activated channel activity in renal epithelial Cells (A6).
Biochimica et biophysica acta, 1991Co-Authors: Y Marunaka, Akito Ohara, P. S. Matsumoto, Douglas C. EatonAbstract:Abstract We studied the effects of guanosine 3′, 5′-cyclic monophosphate (cGMP) and nitroprusside on ion channels in the apical membrane of confluent A6 Cells (a distal Nephron Cell line) cultured on permeable supports for 10–14 days using patch clamp techniques. In Cell-attached patches without any detectable channel activity, activity of a non-selective cation channel with a single-channel conductance of 1 pS was observed after adding nitroprusside. After adding cGMP to the cytosolic surface of inside-out patches with no detectable channel activity, we observed single channel activity similar to the channel observed after adding nitroprusside. These observations imply that nitroprusside activates a non-selective cation channel with small single channel conductance (1 pS) via an increase in cGMP which activates the channel.
Douglas C. Eaton - One of the best experts on this subject based on the ideXlab platform.
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Effects of prostaglandin E2 on amiloride-blockable Na+ channels in a distal Nephron Cell line (A6).
American Journal of Physiology-Cell Physiology, 1994Co-Authors: K. E. Kokko, P. S. Matsumoto, Brian N. Ling, Douglas C. EatonAbstract:We studied the mechanisms by which prostaglandin E2 (PGE2) regulates amiloride-blockable 4-pS Na+ channels in A6 distal Nephron Cells. With each apical Cell-attached patch acting as its own control...
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Cyclic GMP-activated channel activity in renal epithelial Cells (A6).
Biochimica et biophysica acta, 1991Co-Authors: Y Marunaka, Akito Ohara, P. S. Matsumoto, Douglas C. EatonAbstract:Abstract We studied the effects of guanosine 3′, 5′-cyclic monophosphate (cGMP) and nitroprusside on ion channels in the apical membrane of confluent A6 Cells (a distal Nephron Cell line) cultured on permeable supports for 10–14 days using patch clamp techniques. In Cell-attached patches without any detectable channel activity, activity of a non-selective cation channel with a single-channel conductance of 1 pS was observed after adding nitroprusside. After adding cGMP to the cytosolic surface of inside-out patches with no detectable channel activity, we observed single channel activity similar to the channel observed after adding nitroprusside. These observations imply that nitroprusside activates a non-selective cation channel with small single channel conductance (1 pS) via an increase in cGMP which activates the channel.
Alexander N. Combes - One of the best experts on this subject based on the ideXlab platform.
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Single-Cell analysis reveals congruence between kidney organoids and human fetal kidney
Genome Medicine, 2019Co-Authors: Alexander N. Combes, Pei X. Er, L. Zappia, Alicia Oshlack, Melissa H. LittleAbstract:Background Human kidney organoids hold promise for studying development, disease modelling and drug screening. However, the utility of stem Cell-derived kidney tissues will depend on how faithfully these replicate normal fetal development at the level of Cellular identity and complexity. Methods Here, we present an integrated analysis of single Cell datasets from human kidney organoids and human fetal kidney to assess similarities and differences between the component Cell types. Results Clusters in the combined dataset contained Cells from both organoid and fetal kidney with transcriptional congruence for key stromal, endothelial and Nephron Cell type-specific markers. Organoid enriched neural, glial and muscle progenitor populations were also evident. Major transcriptional differences between organoid and human tissue were likely related to technical artefacts. Cell type-specific comparisons revealed differences in stromal, endothelial and Nephron progenitor Cell types including expression of WNT2B in the human fetal kidney stroma. Conclusions This study supports the fidelity of kidney organoids as models of the developing kidney and affirms their potential in disease modelling and drug screening.
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Single-Cell analysis reveals congruence between kidney organoids and human fetal kidney
Genome medicine, 2019Co-Authors: Alexander N. Combes, L. Zappia, Alicia Oshlack, Melissa H. LittleAbstract:Human kidney organoids hold promise for studying development, disease modelling and drug screening. However, the utility of stem Cell-derived kidney tissues will depend on how faithfully these replicate normal fetal development at the level of Cellular identity and complexity. Here, we present an integrated analysis of single Cell datasets from human kidney organoids and human fetal kidney to assess similarities and differences between the component Cell types. Clusters in the combined dataset contained Cells from both organoid and fetal kidney with transcriptional congruence for key stromal, endothelial and Nephron Cell type-specific markers. Organoid enriched neural, glial and muscle progenitor populations were also evident. Major transcriptional differences between organoid and human tissue were likely related to technical artefacts. Cell type-specific comparisons revealed differences in stromal, endothelial and Nephron progenitor Cell types including expression of WNT2B in the human fetal kidney stroma. This study supports the fidelity of kidney organoids as models of the developing kidney and affirms their potential in disease modelling and drug screening.
Heini Murer - One of the best experts on this subject based on the ideXlab platform.
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Na^+/H^+-exchange in A6 Cells: Polarity and vasopressin regulation
The Journal of Membrane Biology, 1992Co-Authors: Valeria Casavola, Lorenzo Guerra, Corinna Helmle-kolb, Stephan J. Reshkin, Heini MurerAbstract:We have analyzed the mechanism of Na^+-dependent pH_i; recovery from an acid load in A6 Cells (an amphibian distal Nephron Cell line) by using the intraCellular pH indicator 2′7′-bis(2-carboxyethyl)5, 6 carboxyfluorescein (BCECF) and single Cell microspectrofluorometry. A6 Cells were found to express Na^+/H^+-exchange activity only on the basolateral membrane: Na^+/H^+-exchange activity follows simple saturation kinetics with an apparent K _mfor Na^+ of approximately 11 m m ; it is inhibited in a competitive manner by ethylisopropylamiloride (EIPA). This Na^+/H^+-exchange activity is inhibited by pharmacological activation of protein kinase A (PKA) as well as of protein kinase C (PKC). Addition of arginine vasopressin (AVP) either at low (subnanomolar) or at high (micromolar) concentrations inhibits Na^+/H^+-exchange activity; AVP stimulates IP_3 production at low concentrations, whereas much higher concentrations are required to stimualte cAMP formation. These findings suggest that in A6 Cells (i) Na^+/H^+-exchange is located in the basolateral membrane and (ii) PKC activation (heralded by IP_3 turnover) is likely to be the mediator of AVP action at low AVP concentrations.
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Na + /H + -exchange in A6 Cells: Polarity and vasopressin regulation
The Journal of membrane biology, 1992Co-Authors: Valeria Casavola, Lorenzo Guerra, Corinna Helmle-kolb, Stephan J. Reshkin, Heini MurerAbstract:We have analyzed the mechanism of Na+-dependent pHi; recovery from an acid load in A6 Cells (an amphibian distal Nephron Cell line) by using the intraCellular pH indicator 2′7′-bis(2-carboxyethyl)5, 6 carboxyfluorescein (BCECF) and single Cell microspectrofluorometry. A6 Cells were found to express Na+/H+-exchange activity only on the basolateral membrane: Na+/H+-exchange activity follows simple saturation kinetics with an apparent Kmfor Na+ of approximately 11 mm; it is inhibited in a competitive manner by ethylisopropylamiloride (EIPA). This Na+/H+-exchange activity is inhibited by pharmacological activation of protein kinase A (PKA) as well as of protein kinase C (PKC). Addition of arginine vasopressin (AVP) either at low (subnanomolar) or at high (micromolar) concentrations inhibits Na+/H+-exchange activity; AVP stimulates IP3 production at low concentrations, whereas much higher concentrations are required to stimualte cAMP formation. These findings suggest that in A6 Cells (i) Na+/H+-exchange is located in the basolateral membrane and (ii) PKC activation (heralded by IP3 turnover) is likely to be the mediator of AVP action at low AVP concentrations.