Stem cell therapy is a promising future enterprise for renal replacement in patients with acute and chronic kidney disease, conditions which affect millions worldwide and currently require patients to undergo lifelong...Stem cell therapy is a promising future enterprise for renal replacement in patients with acute and chronic kidney disease, conditions which affect millions worldwide and currently require patients to undergo lifelong medical treatments through dialysis and/or organ transplant. Reprogramming differentiated renal cells harvested from the patient back into a pluripotent state would decrease the risk of tissue rejection and provide a virtually unlimited supply of cells for regenerative medicine treatments, making it an exciting area of current research in nephrology. Among the major hurdles that need to be overcome before stem cell therapy for the kidney can be applied in a clinical setting are ensuring the fidelity and relative safety of the reprogrammed cells, as well as achieving feasible efficiency in the reprogramming processes that are utilized. Further, improved knowledge about the genetic control of renal lineage development is vital to identifying predictable and efficient reprogramming approaches, such as the expression of key modulators or the regulation of geneactivity through small molecule mimetics. Here, we discuss several recent advances in induced pluripotent stem cell technologies. We also explore strategies that have been successful in renal progenitor generation, and explore what these methods might mean for the development of cell-based regenerative therapies for kidney disease.展开更多
AIM: To investigate whether fetal kidney stem cells(f KSC) ameliorate cisplatin induced acute renal failure(ARF) in rats and promote renal angiogenesis.METHODS: The f KSC were isolated from rat fetuses of gestation da...AIM: To investigate whether fetal kidney stem cells(f KSC) ameliorate cisplatin induced acute renal failure(ARF) in rats and promote renal angiogenesis.METHODS: The f KSC were isolated from rat fetuses of gestation day 16 and expanded in vitro up to 3rd passage. They were characterized for the expression of mesenchymal and renal progenitor markers by flow cytometry and immunocytochemistry, respectively. The in vitro differentiation of f KSC towards epithelial lineage was evaluated by the treatment with specific induction medium and their angiogenic potential by matrigel induced tube formation assay. To study the effect of f KSC in ARF, f KSC labeled with PKH26 were infused in rats with cisplatin induced ARF and, the blood and renal tissues of the rats were collected at different time points. Blood biochemical parameters were studied to evaluate renal function. Renal tissues were evaluated for renal architecture, renal cell proliferation and angiogenesis by immunohistochemistry, renal cell apoptosis by terminal deoxynucleotidyl transferase nickend labeling assay and early expression of angiogenic molecules viz. vascular endothelial growth factor(VEGF), hypoxia-inducible factor(HIF)-1α and endothelial nitric oxide synthase(eN OS) by western blot.RESULTS: The fK SC expressed mesenchymal markers viz. CD29, CD44, CD73, CD90 and CD105 as well asrenal progenitor markers viz. Wt1, Pax2 and Six2. They exhibited a potential to form CD31 and Von Willebrand factor expressing capillary-like structures and could be differentiated into cytokeratin(CK)18 and CK19 positive epithelial cells. Administration of fK SC in rats with ARF as compared to administration of saline alone, resulted in a significant improvement in renal function and histology on day 3(2.33 ± 0.33 vs 3.50 ± 0.34, P < 0.05) and on day 7(0.83 ± 0.16 vs 2.00 ± 0.25, P < 0.05). The infused PKH26 labeled fK SC were observed to engraft in damaged renal tubules and showed increased proliferation and reduced apoptosis(P < 0.05) of renal cells. The kidneys of fK SC as compared to saline treated rats had a higher capillary density on day 3 [13.30 ± 1.54 vs 7.10 ± 1.29, capillaries/high-power fields(HPF), P < 0.05], and on day 7(21.10 ± 1.46 vs 15.00 ± 1.30, capillaries/HPF, P < 0.05). In addition, kidneys of fK SC treated rats had an upregulation of angiogenic proteins hypoxia-inducible factor-1α, VEGF and eN OS on day 3(P < 0.05).CONCLUSION: Our study shows that fK SC ameliorate cisplatin induced ARF in rats and promote renal angiogenesis, which may be an important therapeutic mechanism of these stem cells in the disease.展开更多
Objective: Memory stem T cells(Tscm) have attracted attention because of their enhanced self-renewal, multipotent capacity, and anti-tumor capacities. However, little is known about Tscm in patients with renal clear c...Objective: Memory stem T cells(Tscm) have attracted attention because of their enhanced self-renewal, multipotent capacity, and anti-tumor capacities. However, little is known about Tscm in patients with renal clear cell carcinoma(RCC) and the role of Wnt signaling in these cells. We evaluated Tscm from RCC patients concerning their activation of Wnt signaling in vitro and explored the mechanism of preferential survival.Methods: Flow cytometry identified surface markers and cytokines produced from accumulated Tscm in the presence of the glycogen synthase kinase beta inhibitor TWS119. Apoptosis was evaluated after induction using tumor necrosis factor-alpha.Immunofluorescence and Western blot analyses were used to investigate the activation of the nuclear factor-kappa B(NF-КB)pathway.Results: RCC patients had a similar percentage of CD4^+ and CD8^+ Tscm as healthy donors. Activation of Wnt signaling by TWS119 resulted in the accumulation of Tscm in activated T cells, but reversal of differentiated T cells to Tscm was not achieved.Preferential survival of Tscm was associated with increased anti-apoptotic ability mediated downstream of the NF-КB activation pathway.Conclusions: The finding that Tscm can accumulate by Wnt signaling in vitro in blood from RCC patients will help in devising new cancer therapy strategies of Tscm-based adoptive immunotherapy, such as dendritic cell-stimulated Tscm, and T cell receptor or chimeric antigen receptor-engineered Tscm.展开更多
Kidney disease is an escalating global health problem,for which the formulation of therapeutic approaches using stem cells has received increasing research attention.The complexity of kidney anatomy and function,which...Kidney disease is an escalating global health problem,for which the formulation of therapeutic approaches using stem cells has received increasing research attention.The complexity of kidney anatomy and function,which includes the diversity of renal cell types,poses formidable challenges in the identification of methods to generate replacement structures.Recent work using the zebrafish has revealed their high capacity to regenerate the integral working units of the kidney,known as nephrons,following acute injury.Here,we discuss these findings and explore the ways that zebrafish can be further utilized to gain a deeper molecular appreciation of renal stem cell biology,which may uncover important clues for regenerative medicine.展开更多
Solid tumors in adults constitute a heterogeneous group of malignancy originating from various organ systems. Solid tumors are not completely curable by chemotherapy, even though some subgroups are very chemo-sensitiv...Solid tumors in adults constitute a heterogeneous group of malignancy originating from various organ systems. Solid tumors are not completely curable by chemotherapy, even though some subgroups are very chemo-sensitive. Recently, oncologists have focused on the use of allogeneic hematopoietic stem cell transplantation(alloHSCT) with reduced intensity conditioning(RIC) for the treatment of some refractory solid tumors. After the demonstration of allogeneic graft-versus-leukemia effect in patients with hematological malignancies who received allo-HSCT, investigators evaluated this effect in patients with refractory metastatic solid tumors. According to data from experimental animal models and preliminary clinical trials, a graft-versus-tumor(GvT) effect may also be observed in the treatment of some solid tumors(e.g., renal cell cancer, colorectal cancer, etc.) after allo-HSCT with RIC. The use of RIC regimens offers an opportunity of achieving full-donor engraftment with GvT effect, as well as, a reduced transplant-related mortality. Current literature suggests that allo-HSCT with RIC might become a choice for elderly and medically fragile patients with refractory metastatic solid tumors.展开更多
Background: Autosomal dominant polycystic kidney disease is a condition mainly characterized by the progressive development and enlargement of cysts in each kid ney. In this process a high rate of proliferation and ap...Background: Autosomal dominant polycystic kidney disease is a condition mainly characterized by the progressive development and enlargement of cysts in each kid ney. In this process a high rate of proliferation and apoptosis of tubular cells has been documented and interpreted as a futile attempt of tissue repair. In consideration of the role of stem cells in reparative processes we investigated the presence and localization of CD133 + CD24+ renal progenitors in renal ADPKD tissue and cells. Methods: Two normal kidneys and two ADPKD kidneys were examined. CD133 and CD24 expression was investigated by confocal microscopy and immunoblotting. Furthermore cystic isolated cells and cultured immortalized cells were characterized. Results: CD133 and CD24 have the same localization in ADPKD tissues and in normal kidneys: expression is restricted to a subset of epithelial cells (PEC) of Bowman’s capsule and to tubular cells in a focal and segmental pattern. Furthermore, in ADPKD tissue, cysts diffusely express CD133 and CD24. According to a quantitative analysis in ADPKD tissue CD133 + CD24 + cells are statistically more expressed in tubules (p < 0.001) and less expressed in the Bowman’s capsule (p = 0.0016) compared to the same localizations in control tissue. Conclusions: CD133 and CD24 antigens, typically expressed by renal epithelial progenitors, are more expressed in ADPKD tubules and highly expressed in ADPKD cysts. Whether CD133 and CD24 expression would signify renal progenitor recruitment or alternatively an expression pattern of the dedifferentiation of ADPKD cells remains unclear.展开更多
Endothelial cell therapy has been implicated to enhance tissue regeneration and vascularization in ischemic kidney. However, no published study has yet examined direct effects of endothelial cell treatment in kidney r...Endothelial cell therapy has been implicated to enhance tissue regeneration and vascularization in ischemic kidney. However, no published study has yet examined direct effects of endothelial cell treatment in kidney recovery. This study investigated the therapeutic efficacy of endothelial cells in a mouse model with acute kidney injury (AKI). Thus, human embryonic stem cells-derived endothelial cells (hESC-ECs) labeled with a reporter system encoding a double fusion reporter gene for firefly luciferase (Fluc) and green fluorescent protein (GFP) were characterized by Fluc imaging and immunofluoresence staining. Cultured hESC-ECs (1×106) were injected into ischemic kidney shortly after AKI. Survival of the transplanted hESC-ECs was monitored in vivo from day 1 to 14 after endothelial cell transplantation and potential impact of hESC-EC treatment on renal regeneration was assessed by histological analyses. We report that a substantial level of bioluminescence activity was detected 24 h after hESC-EC injection followed by a gradual decline from 1 to 14 d. Human ESC-ECs markedly accelerated kidney cell proliferation in response to ischaemia-induced damage, indicated by an elevated number of BrdU+ cells. Co-expression of Sca-1, a kidney stem cell proliferation marker, and BrdU further suggested that the observed stimulation in renal cell regeneration was, at least in part, due to increased proliferation of renal resident stem cells especially within the medullary cords and arteriole. Differentiation of hESC-ECs to smooth muscle cells was also observed at an early stage of kidney recovery. In summary, our results suggest that endothelial cell therapy facilitates kidney recovery by promoting vascularization, trans-differentiation and endogenous renal stem cell proliferation in AKI.展开更多
Tissue homeostasis, accomplished through the self-renewai and differentiation of resident stem cells, is critical for the maintenance of adult tissues throughout an animal＇s lifetime, Adult Drosophila Malpighian tubu...Tissue homeostasis, accomplished through the self-renewai and differentiation of resident stem cells, is critical for the maintenance of adult tissues throughout an animal＇s lifetime, Adult Drosophila Malpighian tubules （MTs or fly kidney） are maintained by renal and nephric stem cells （RNSCs） via self-renewing divisions, however, it is unclear how RNSC proliferation and differentiation are regulated. Here we show that EGFR/MAPK signaling is dispensable for RNSC maintenance, but required for RNSC proliferation in vivo. Inacti- vation of the EGFR/MAPK pathway blocks or greatly retards RNSC cell cycle progression; conversely, over-activation of EGFR/MAPK signaling results in RNSC over-proliferation and disrupts the normal differentiation of renablasts （RBs）, the immediate daughters of RNSC divisions. Our data further suggest that EGFR/MAPK signaling functions independently of JAK/STAT signaling and that dMyc and CycE partially mediate EGFR/MAPK signaling in MTs. Together, our data suggest a principal role of EGFR/MAPK signaling in regulating RNSC proliferation, which may provide important clues for understanding mammalian kidney repair and regeneration following injury.展开更多
Background Chronic kidney disease （CDK） is a worldwide health problem, but there is currently no effective treatment that can completely cure this disease. Recently, studies with mesenchymal stem cells （MSCs） on t...Background Chronic kidney disease （CDK） is a worldwide health problem, but there is currently no effective treatment that can completely cure this disease. Recently, studies with mesenchymal stem cells （MSCs） on treating various renal diseases have shown breakthroughs. This study is to observe the homing features of MSCs transplanted via kidney artery and effects on renal fibrosis in a reversible unilateral ureteral obstruction （R-UUO） model. Methods Thirty-six Balb/c mice were divided into UUO group, UUO-MSC group, and sham group randomly, with 12 mice in each group. The MSCs had been infected by a lentiviral vector to express stably the luciferase reporter gene and green fluorescence protein genes （Luc-GFP-MSC）. Homing of MSCs was tracked using in vivo imaging system （IVIS） 1, 3, 14, and 28 days after transplantation. Imaging results were verified by detecting GFP expression in frozen section under a fluorescence microscope. E-cadherin, α-SMA, TGF-β1, and TNF-α mRNA expression in all groups at 1 and 4 weeks after transplantation were analyzed by quantitative PCR. Results Transplanted Luc-GFP-MSCs showed increased Luciferase expression 3 days after transplantation. The expression decreased from 7 days, weakened thereafter and could not be detected 14 days after transplantation. Quantitative PCR results showed that all gene expressions in UUO group and UUO-MSC group at 1 week had no statistical difference, while at 4 weeks, except TGF-β expression （P〉0.05）, the expression of E-cadherin, α-SMA, and TNF-α in the above two groups have statistical difference （P〈0.01）. Conclusion IVIS enables fast, noninvasive, and intuitive tracking of MSC homing in vivo. MSCs can be taken home to kidney tissues of the diseased side in R-UUO model, and renal interstitial fibrosis can be improved as well.展开更多
基金Supported by National Institutes of Health,No.DP2 OD008470,R01 DK100237Start-up funds from the University of Notre Dame and College of Sciencea generous donation for stem cell research to the University of Notre Dame by Elizabeth and Michael Gallagher on behalf of the Gallagher family
文摘Stem cell therapy is a promising future enterprise for renal replacement in patients with acute and chronic kidney disease, conditions which affect millions worldwide and currently require patients to undergo lifelong medical treatments through dialysis and/or organ transplant. Reprogramming differentiated renal cells harvested from the patient back into a pluripotent state would decrease the risk of tissue rejection and provide a virtually unlimited supply of cells for regenerative medicine treatments, making it an exciting area of current research in nephrology. Among the major hurdles that need to be overcome before stem cell therapy for the kidney can be applied in a clinical setting are ensuring the fidelity and relative safety of the reprogrammed cells, as well as achieving feasible efficiency in the reprogramming processes that are utilized. Further, improved knowledge about the genetic control of renal lineage development is vital to identifying predictable and efficient reprogramming approaches, such as the expression of key modulators or the regulation of geneactivity through small molecule mimetics. Here, we discuss several recent advances in induced pluripotent stem cell technologies. We also explore strategies that have been successful in renal progenitor generation, and explore what these methods might mean for the development of cell-based regenerative therapies for kidney disease.
基金Supported by An extramural grant from the Department of Biotechnology,Government of India(BT/PR6519/MED/14/826/2005)sanctioned(to Nityanand S)
文摘AIM: To investigate whether fetal kidney stem cells(f KSC) ameliorate cisplatin induced acute renal failure(ARF) in rats and promote renal angiogenesis.METHODS: The f KSC were isolated from rat fetuses of gestation day 16 and expanded in vitro up to 3rd passage. They were characterized for the expression of mesenchymal and renal progenitor markers by flow cytometry and immunocytochemistry, respectively. The in vitro differentiation of f KSC towards epithelial lineage was evaluated by the treatment with specific induction medium and their angiogenic potential by matrigel induced tube formation assay. To study the effect of f KSC in ARF, f KSC labeled with PKH26 were infused in rats with cisplatin induced ARF and, the blood and renal tissues of the rats were collected at different time points. Blood biochemical parameters were studied to evaluate renal function. Renal tissues were evaluated for renal architecture, renal cell proliferation and angiogenesis by immunohistochemistry, renal cell apoptosis by terminal deoxynucleotidyl transferase nickend labeling assay and early expression of angiogenic molecules viz. vascular endothelial growth factor(VEGF), hypoxia-inducible factor(HIF)-1α and endothelial nitric oxide synthase(eN OS) by western blot.RESULTS: The fK SC expressed mesenchymal markers viz. CD29, CD44, CD73, CD90 and CD105 as well asrenal progenitor markers viz. Wt1, Pax2 and Six2. They exhibited a potential to form CD31 and Von Willebrand factor expressing capillary-like structures and could be differentiated into cytokeratin(CK)18 and CK19 positive epithelial cells. Administration of fK SC in rats with ARF as compared to administration of saline alone, resulted in a significant improvement in renal function and histology on day 3(2.33 ± 0.33 vs 3.50 ± 0.34, P < 0.05) and on day 7(0.83 ± 0.16 vs 2.00 ± 0.25, P < 0.05). The infused PKH26 labeled fK SC were observed to engraft in damaged renal tubules and showed increased proliferation and reduced apoptosis(P < 0.05) of renal cells. The kidneys of fK SC as compared to saline treated rats had a higher capillary density on day 3 [13.30 ± 1.54 vs 7.10 ± 1.29, capillaries/high-power fields(HPF), P < 0.05], and on day 7(21.10 ± 1.46 vs 15.00 ± 1.30, capillaries/HPF, P < 0.05). In addition, kidneys of fK SC treated rats had an upregulation of angiogenic proteins hypoxia-inducible factor-1α, VEGF and eN OS on day 3(P < 0.05).CONCLUSION: Our study shows that fK SC ameliorate cisplatin induced ARF in rats and promote renal angiogenesis, which may be an important therapeutic mechanism of these stem cells in the disease.
基金supported by grants from the National Science and Technology Support Project (Grant No. 2015BAI12B12)the National Natural Science Foundation of China (Grant No. 81401887)+1 种基金the National Natural Science Foundation of China (Grant No. 81470293)the Tianjin Natural Science Foundation (Grant No. 14JCQNJC11500)
文摘Objective: Memory stem T cells(Tscm) have attracted attention because of their enhanced self-renewal, multipotent capacity, and anti-tumor capacities. However, little is known about Tscm in patients with renal clear cell carcinoma(RCC) and the role of Wnt signaling in these cells. We evaluated Tscm from RCC patients concerning their activation of Wnt signaling in vitro and explored the mechanism of preferential survival.Methods: Flow cytometry identified surface markers and cytokines produced from accumulated Tscm in the presence of the glycogen synthase kinase beta inhibitor TWS119. Apoptosis was evaluated after induction using tumor necrosis factor-alpha.Immunofluorescence and Western blot analyses were used to investigate the activation of the nuclear factor-kappa B(NF-КB)pathway.Results: RCC patients had a similar percentage of CD4^+ and CD8^+ Tscm as healthy donors. Activation of Wnt signaling by TWS119 resulted in the accumulation of Tscm in activated T cells, but reversal of differentiated T cells to Tscm was not achieved.Preferential survival of Tscm was associated with increased anti-apoptotic ability mediated downstream of the NF-КB activation pathway.Conclusions: The finding that Tscm can accumulate by Wnt signaling in vitro in blood from RCC patients will help in devising new cancer therapy strategies of Tscm-based adoptive immunotherapy, such as dendritic cell-stimulated Tscm, and T cell receptor or chimeric antigen receptor-engineered Tscm.
基金Supported by National Institutes of Health,No.DP2 OD008470Private funding was provided from the University of Notre Dame College of Science and Graduate Schoola generous donation to support stem cell research provided by the Gallagher Family
文摘Kidney disease is an escalating global health problem,for which the formulation of therapeutic approaches using stem cells has received increasing research attention.The complexity of kidney anatomy and function,which includes the diversity of renal cell types,poses formidable challenges in the identification of methods to generate replacement structures.Recent work using the zebrafish has revealed their high capacity to regenerate the integral working units of the kidney,known as nephrons,following acute injury.Here,we discuss these findings and explore the ways that zebrafish can be further utilized to gain a deeper molecular appreciation of renal stem cell biology,which may uncover important clues for regenerative medicine.
文摘Solid tumors in adults constitute a heterogeneous group of malignancy originating from various organ systems. Solid tumors are not completely curable by chemotherapy, even though some subgroups are very chemo-sensitive. Recently, oncologists have focused on the use of allogeneic hematopoietic stem cell transplantation(alloHSCT) with reduced intensity conditioning(RIC) for the treatment of some refractory solid tumors. After the demonstration of allogeneic graft-versus-leukemia effect in patients with hematological malignancies who received allo-HSCT, investigators evaluated this effect in patients with refractory metastatic solid tumors. According to data from experimental animal models and preliminary clinical trials, a graft-versus-tumor(GvT) effect may also be observed in the treatment of some solid tumors(e.g., renal cell cancer, colorectal cancer, etc.) after allo-HSCT with RIC. The use of RIC regimens offers an opportunity of achieving full-donor engraftment with GvT effect, as well as, a reduced transplant-related mortality. Current literature suggests that allo-HSCT with RIC might become a choice for elderly and medically fragile patients with refractory metastatic solid tumors.
文摘Background: Autosomal dominant polycystic kidney disease is a condition mainly characterized by the progressive development and enlargement of cysts in each kid ney. In this process a high rate of proliferation and apoptosis of tubular cells has been documented and interpreted as a futile attempt of tissue repair. In consideration of the role of stem cells in reparative processes we investigated the presence and localization of CD133 + CD24+ renal progenitors in renal ADPKD tissue and cells. Methods: Two normal kidneys and two ADPKD kidneys were examined. CD133 and CD24 expression was investigated by confocal microscopy and immunoblotting. Furthermore cystic isolated cells and cultured immortalized cells were characterized. Results: CD133 and CD24 have the same localization in ADPKD tissues and in normal kidneys: expression is restricted to a subset of epithelial cells (PEC) of Bowman’s capsule and to tubular cells in a focal and segmental pattern. Furthermore, in ADPKD tissue, cysts diffusely express CD133 and CD24. According to a quantitative analysis in ADPKD tissue CD133 + CD24 + cells are statistically more expressed in tubules (p < 0.001) and less expressed in the Bowman’s capsule (p = 0.0016) compared to the same localizations in control tissue. Conclusions: CD133 and CD24 antigens, typically expressed by renal epithelial progenitors, are more expressed in ADPKD tubules and highly expressed in ADPKD cysts. Whether CD133 and CD24 expression would signify renal progenitor recruitment or alternatively an expression pattern of the dedifferentiation of ADPKD cells remains unclear.
基金supported by the National Key Scientific Program of China(2011CB964903)the National Natural Science Foundation of China(31071308,30970746,81220108015)Doctoral Fund of Ministry of Education of China(20090031110024)
文摘Endothelial cell therapy has been implicated to enhance tissue regeneration and vascularization in ischemic kidney. However, no published study has yet examined direct effects of endothelial cell treatment in kidney recovery. This study investigated the therapeutic efficacy of endothelial cells in a mouse model with acute kidney injury (AKI). Thus, human embryonic stem cells-derived endothelial cells (hESC-ECs) labeled with a reporter system encoding a double fusion reporter gene for firefly luciferase (Fluc) and green fluorescent protein (GFP) were characterized by Fluc imaging and immunofluoresence staining. Cultured hESC-ECs (1×106) were injected into ischemic kidney shortly after AKI. Survival of the transplanted hESC-ECs was monitored in vivo from day 1 to 14 after endothelial cell transplantation and potential impact of hESC-EC treatment on renal regeneration was assessed by histological analyses. We report that a substantial level of bioluminescence activity was detected 24 h after hESC-EC injection followed by a gradual decline from 1 to 14 d. Human ESC-ECs markedly accelerated kidney cell proliferation in response to ischaemia-induced damage, indicated by an elevated number of BrdU+ cells. Co-expression of Sca-1, a kidney stem cell proliferation marker, and BrdU further suggested that the observed stimulation in renal cell regeneration was, at least in part, due to increased proliferation of renal resident stem cells especially within the medullary cords and arteriole. Differentiation of hESC-ECs to smooth muscle cells was also observed at an early stage of kidney recovery. In summary, our results suggest that endothelial cell therapy facilitates kidney recovery by promoting vascularization, trans-differentiation and endogenous renal stem cell proliferation in AKI.
基金supported by grants from the National Natural Science Foundation of China(No.31271582)Temasek Life Sciences Laboratory and Singapore Millennium FoundationBeijing Municipal Commission of Education(No.010135336400)
文摘Tissue homeostasis, accomplished through the self-renewai and differentiation of resident stem cells, is critical for the maintenance of adult tissues throughout an animal＇s lifetime, Adult Drosophila Malpighian tubules （MTs or fly kidney） are maintained by renal and nephric stem cells （RNSCs） via self-renewing divisions, however, it is unclear how RNSC proliferation and differentiation are regulated. Here we show that EGFR/MAPK signaling is dispensable for RNSC maintenance, but required for RNSC proliferation in vivo. Inacti- vation of the EGFR/MAPK pathway blocks or greatly retards RNSC cell cycle progression; conversely, over-activation of EGFR/MAPK signaling results in RNSC over-proliferation and disrupts the normal differentiation of renablasts （RBs）, the immediate daughters of RNSC divisions. Our data further suggest that EGFR/MAPK signaling functions independently of JAK/STAT signaling and that dMyc and CycE partially mediate EGFR/MAPK signaling in MTs. Together, our data suggest a principal role of EGFR/MAPK signaling in regulating RNSC proliferation, which may provide important clues for understanding mammalian kidney repair and regeneration following injury.
文摘Background Chronic kidney disease （CDK） is a worldwide health problem, but there is currently no effective treatment that can completely cure this disease. Recently, studies with mesenchymal stem cells （MSCs） on treating various renal diseases have shown breakthroughs. This study is to observe the homing features of MSCs transplanted via kidney artery and effects on renal fibrosis in a reversible unilateral ureteral obstruction （R-UUO） model. Methods Thirty-six Balb/c mice were divided into UUO group, UUO-MSC group, and sham group randomly, with 12 mice in each group. The MSCs had been infected by a lentiviral vector to express stably the luciferase reporter gene and green fluorescence protein genes （Luc-GFP-MSC）. Homing of MSCs was tracked using in vivo imaging system （IVIS） 1, 3, 14, and 28 days after transplantation. Imaging results were verified by detecting GFP expression in frozen section under a fluorescence microscope. E-cadherin, α-SMA, TGF-β1, and TNF-α mRNA expression in all groups at 1 and 4 weeks after transplantation were analyzed by quantitative PCR. Results Transplanted Luc-GFP-MSCs showed increased Luciferase expression 3 days after transplantation. The expression decreased from 7 days, weakened thereafter and could not be detected 14 days after transplantation. Quantitative PCR results showed that all gene expressions in UUO group and UUO-MSC group at 1 week had no statistical difference, while at 4 weeks, except TGF-β expression （P〉0.05）, the expression of E-cadherin, α-SMA, and TNF-α in the above two groups have statistical difference （P〈0.01）. Conclusion IVIS enables fast, noninvasive, and intuitive tracking of MSC homing in vivo. MSCs can be taken home to kidney tissues of the diseased side in R-UUO model, and renal interstitial fibrosis can be improved as well.
