Diabetes mellitus(diabetes) is a devastating disease that affects millions of people globally and causes a myriad of complications that lead to both patient morbidity and mortality. Currently available therapies, incl...Diabetes mellitus(diabetes) is a devastating disease that affects millions of people globally and causes a myriad of complications that lead to both patient morbidity and mortality. Currently available therapies, including insulin injection and beta cell replacement through either pancreas or pancreatic islet transplantation, are limited by the availability of organs. Stem cells provide an alternative treatment option for beta cell replacement through selective differentiation of stem cells into cells that recognize glucose and produce and secrete insulin. Embryonic stem cells, albeit pluripotent, face a number of challenges, including ethical and political concerns and potential teratoma formation. Adipose tissue represents an alternative source of multipotent mesenchymal stem cells, which can be obtained using a relatively simple, non-invasive, and inexpensive method. Similarly to other adult mesenchymal stem cells, adipose-derived stem cells(ADSCs) are capable of differentiating into insulin-producing cells. They are also capable of vasculogenesis and angiogenesis, which facilitate engraftment of donor pancreatic islets when co-transplanted. Additionally, anti-inflammatory and immunomodulatory effects of ADSCs can protect donorislets during the early phase of transplantation and subsequently improve engraftment of donor islets into the recipient organ. Although ADSC-therapy is still in its infancy, the potential benefits of ADSCs are far reaching.展开更多
The intra-islet microvasculature is a critical interface between the blood and islet endocrine cells governing a number of cellular and pathophysiological processes associated with the pancreatic tissue. A growing bod...The intra-islet microvasculature is a critical interface between the blood and islet endocrine cells governing a number of cellular and pathophysiological processes associated with the pancreatic tissue. A growing body of evidence indicates a strong functional and physical interdependency of β-cells with endothelial cells(ECs), the building blocks of islet microvasculature. Intra-islet ECs, actively regulate vascular permeability and appear to play a role in fine-tuning blood glucose sensing and regulation. These cells also tend to behave as "guardians", controlling the expression and movement of a number of important immune mediators, thereby strongly contributing to the physiology of islets. This review will focus on the molecular signalling and crosstalk between the intra-islet ECs and β-cells and how their relationship can be a potential target for intervention strategies in islet pathology and islet transplantation.展开更多
Human embryonic stem cells (hESC) can be induced to differentiate to trophoblast by bone morphogenetic proteins (BMPs) and by aggregation to form embryoid bodies (EB), but there are many differences and controversies ...Human embryonic stem cells (hESC) can be induced to differentiate to trophoblast by bone morphogenetic proteins (BMPs) and by aggregation to form embryoid bodies (EB), but there are many differences and controversies regarding the nature of the differentiated cells. Our goals herein were to determine if BG02 cells form trophoblast-like cells (a) in the presence of BMP4-plus-basic fibroblast growth factor (FGF-2) and (b) upon EB formation, and (c) whether the BMP4 antagonist noggin elicits direct effects on gene expression and hormone production in the cells. Transcriptome profiling of hESC incubated with BMP4/FGF-2 showed a down-regulation of pluripotency-associated genes, an up-regulation of trophoblast-associated genes, and either a down-regulation or no change in gene expression for many markers of the three embryonic germ layers. Yet, there was up-regulation of several genes associated with mesoderm, ectoderm, and endoderm, strongly suggesting that differentiation to trophoblast-like cells under the conditions used does not yield a homogeneous cell type. Several genes, heretofore unreported, were identified that are altered in hESC in response to BMP4-mediated differentiation. The production of human chorionic gonadotropin (hCG), progesterone, and estradiol in the differentiated cells confirmed that trophoblast-like cells were obtained. Gene expression by EB was characterized by an up-regulation of a number of genes associated with trophoblast, ectoderm, endoderm, and mesoderm, and the production of hCG and progesterone confirmed that trophoblast-like cells were formed. These results suggest that, in the presence of FGF-2, BG02 cells respond to BMP4 to yield trophoblast-like cells, which are also obtained upon EB formation. Thus, BMP4-mediated differentiation of hESC represents a viable cell system for studying early developmental events post-implantation;however, up-regulation of non-trophoblast genes suggests a somewhat diverse response to BMP4/FGF-2. Noggin altered the transcription of a limited number of genes but, not surprisingly, did not lead to secretion of hormones.展开更多
Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabe...Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabetes.The countries where islet transplantation has not been explored suffer from insufficient knowledge concerning key elements of the isolation process.Donor and organ procurement parameters impact human islet yield,although for research purposes,islet yield may be secondary in importance to islet function.This paper will analyze the feasibility of research-only human islet isolation and signify parameters underlying a successful yield in the Indian population.This eventually can make islet transplantation a clinical reality in India.Method:After receiving the consent for procuring brain-dead pancreas from the first-degree of relatives,samples were collected and transported in a transportation buffer at 4℃.The procedure consists of a mechanically enhanced enzymatic digestion of the pancreas,after which it was taken for purification using Ficoll method,followed by islet quality testing.Results:Through 15 isolations done over a span of approximately 2 years during the COVID pandemic in India,we confirm that ischemic time and glycated hemoglobin,each have a negative impact on isolation purity and yield.Notably,extending cold ischemic tim beyond the typical clinical isolation cutoff of 12 hours(to≥18 h)had a huge impact on islet function and yield.Age had a negative correlation with islet yield;however other biological parameters(specifically body mass index)and isolation variables appear to make a significant contribution to the heterogeneity of human islet yield.Our current work demonstrates the feasibility of extending acceptable cold ischemic time for research-focused human islet isolation and highlights the biological variation in isolation of human islets from donors with and without diabetes.Conclusion:India requires establishment of an islet transplant program using the current standard methods of“islet isolation”and donor program and process.Research should focus on improving standards in the islet preparation process to increase the number of successful preparations,shorten the isolation time,and increase patient safety so that the theoretical risk involved can become a practical reality.展开更多
Myogenesis is a complex process required for skeletal muscle formation during embryonic development and for regeneration and growth of myofibers in adults. Accumulating evidence suggests that long non-coding RNAs (In...Myogenesis is a complex process required for skeletal muscle formation during embryonic development and for regeneration and growth of myofibers in adults. Accumulating evidence suggests that long non-coding RNAs (IncRNAs) play key roles in regulating cell fate decision and function in various tissues. However, the role of IncRNAs in the regulation of myogenesis remains poorly understood. In this study, we identifed a novel muscle-enriched IncRNA called 'Myolinc (AK142388)', which we functionally characterized in the C2C12 myoblast cell line. Myolinc is predominately localized in the nucleus, and its levels increase upon induction of the differ-entiation. Knockdown of Myolinc impairs the expression of myogenic regulatory factors and formation of multi-nucleated myotubes in cultured myoblasts. Myolinc also regulates the expression of Filipl in a cis-manner. Similar to MyoUnc, knockdown of FiUpl inhi-bits myogenic differentiation. Furthermore, Myolinc binds to TAR DNA-binding protein 43 (TDP-43), a DNA/RNA-binding protein that regulates the expression of muscle genes (e.g. Actal and MyoD). Knockdown of TDP-43 inhibits myogenic differentiation. We also show that Myolinc-TDP-43 interaction is essential for the binding of TDP-43 to the promoter regions of muscle marker genes. Finally, we show that silencing of Myolinc inhibits skeletal muscle regeneration in adult mice. Altogether, our study identifies a novel IncRNA that controls key regulatory networks of myogenesis.展开更多
文摘Diabetes mellitus(diabetes) is a devastating disease that affects millions of people globally and causes a myriad of complications that lead to both patient morbidity and mortality. Currently available therapies, including insulin injection and beta cell replacement through either pancreas or pancreatic islet transplantation, are limited by the availability of organs. Stem cells provide an alternative treatment option for beta cell replacement through selective differentiation of stem cells into cells that recognize glucose and produce and secrete insulin. Embryonic stem cells, albeit pluripotent, face a number of challenges, including ethical and political concerns and potential teratoma formation. Adipose tissue represents an alternative source of multipotent mesenchymal stem cells, which can be obtained using a relatively simple, non-invasive, and inexpensive method. Similarly to other adult mesenchymal stem cells, adipose-derived stem cells(ADSCs) are capable of differentiating into insulin-producing cells. They are also capable of vasculogenesis and angiogenesis, which facilitate engraftment of donor pancreatic islets when co-transplanted. Additionally, anti-inflammatory and immunomodulatory effects of ADSCs can protect donorislets during the early phase of transplantation and subsequently improve engraftment of donor islets into the recipient organ. Although ADSC-therapy is still in its infancy, the potential benefits of ADSCs are far reaching.
文摘The intra-islet microvasculature is a critical interface between the blood and islet endocrine cells governing a number of cellular and pathophysiological processes associated with the pancreatic tissue. A growing body of evidence indicates a strong functional and physical interdependency of β-cells with endothelial cells(ECs), the building blocks of islet microvasculature. Intra-islet ECs, actively regulate vascular permeability and appear to play a role in fine-tuning blood glucose sensing and regulation. These cells also tend to behave as "guardians", controlling the expression and movement of a number of important immune mediators, thereby strongly contributing to the physiology of islets. This review will focus on the molecular signalling and crosstalk between the intra-islet ECs and β-cells and how their relationship can be a potential target for intervention strategies in islet pathology and islet transplantation.
文摘Human embryonic stem cells (hESC) can be induced to differentiate to trophoblast by bone morphogenetic proteins (BMPs) and by aggregation to form embryoid bodies (EB), but there are many differences and controversies regarding the nature of the differentiated cells. Our goals herein were to determine if BG02 cells form trophoblast-like cells (a) in the presence of BMP4-plus-basic fibroblast growth factor (FGF-2) and (b) upon EB formation, and (c) whether the BMP4 antagonist noggin elicits direct effects on gene expression and hormone production in the cells. Transcriptome profiling of hESC incubated with BMP4/FGF-2 showed a down-regulation of pluripotency-associated genes, an up-regulation of trophoblast-associated genes, and either a down-regulation or no change in gene expression for many markers of the three embryonic germ layers. Yet, there was up-regulation of several genes associated with mesoderm, ectoderm, and endoderm, strongly suggesting that differentiation to trophoblast-like cells under the conditions used does not yield a homogeneous cell type. Several genes, heretofore unreported, were identified that are altered in hESC in response to BMP4-mediated differentiation. The production of human chorionic gonadotropin (hCG), progesterone, and estradiol in the differentiated cells confirmed that trophoblast-like cells were obtained. Gene expression by EB was characterized by an up-regulation of a number of genes associated with trophoblast, ectoderm, endoderm, and mesoderm, and the production of hCG and progesterone confirmed that trophoblast-like cells were formed. These results suggest that, in the presence of FGF-2, BG02 cells respond to BMP4 to yield trophoblast-like cells, which are also obtained upon EB formation. Thus, BMP4-mediated differentiation of hESC represents a viable cell system for studying early developmental events post-implantation;however, up-regulation of non-trophoblast genes suggests a somewhat diverse response to BMP4/FGF-2. Noggin altered the transcription of a limited number of genes but, not surprisingly, did not lead to secretion of hormones.
文摘Background:Diabetes is a widespread disease with increasing prevalence.Transplantation of islets of Langerhans is a viable treatment for a selected group of patients with repeated hypoglycemic episodes in type 1 diabetes.The countries where islet transplantation has not been explored suffer from insufficient knowledge concerning key elements of the isolation process.Donor and organ procurement parameters impact human islet yield,although for research purposes,islet yield may be secondary in importance to islet function.This paper will analyze the feasibility of research-only human islet isolation and signify parameters underlying a successful yield in the Indian population.This eventually can make islet transplantation a clinical reality in India.Method:After receiving the consent for procuring brain-dead pancreas from the first-degree of relatives,samples were collected and transported in a transportation buffer at 4℃.The procedure consists of a mechanically enhanced enzymatic digestion of the pancreas,after which it was taken for purification using Ficoll method,followed by islet quality testing.Results:Through 15 isolations done over a span of approximately 2 years during the COVID pandemic in India,we confirm that ischemic time and glycated hemoglobin,each have a negative impact on isolation purity and yield.Notably,extending cold ischemic tim beyond the typical clinical isolation cutoff of 12 hours(to≥18 h)had a huge impact on islet function and yield.Age had a negative correlation with islet yield;however other biological parameters(specifically body mass index)and isolation variables appear to make a significant contribution to the heterogeneity of human islet yield.Our current work demonstrates the feasibility of extending acceptable cold ischemic time for research-focused human islet isolation and highlights the biological variation in isolation of human islets from donors with and without diabetes.Conclusion:India requires establishment of an islet transplant program using the current standard methods of“islet isolation”and donor program and process.Research should focus on improving standards in the islet preparation process to increase the number of successful preparations,shorten the isolation time,and increase patient safety so that the theoretical risk involved can become a practical reality.
文摘Myogenesis is a complex process required for skeletal muscle formation during embryonic development and for regeneration and growth of myofibers in adults. Accumulating evidence suggests that long non-coding RNAs (IncRNAs) play key roles in regulating cell fate decision and function in various tissues. However, the role of IncRNAs in the regulation of myogenesis remains poorly understood. In this study, we identifed a novel muscle-enriched IncRNA called 'Myolinc (AK142388)', which we functionally characterized in the C2C12 myoblast cell line. Myolinc is predominately localized in the nucleus, and its levels increase upon induction of the differ-entiation. Knockdown of Myolinc impairs the expression of myogenic regulatory factors and formation of multi-nucleated myotubes in cultured myoblasts. Myolinc also regulates the expression of Filipl in a cis-manner. Similar to MyoUnc, knockdown of FiUpl inhi-bits myogenic differentiation. Furthermore, Myolinc binds to TAR DNA-binding protein 43 (TDP-43), a DNA/RNA-binding protein that regulates the expression of muscle genes (e.g. Actal and MyoD). Knockdown of TDP-43 inhibits myogenic differentiation. We also show that Myolinc-TDP-43 interaction is essential for the binding of TDP-43 to the promoter regions of muscle marker genes. Finally, we show that silencing of Myolinc inhibits skeletal muscle regeneration in adult mice. Altogether, our study identifies a novel IncRNA that controls key regulatory networks of myogenesis.