Shigeki Sugii | Agency of Science and Technology, Singapore (original) (raw)

Papers by Shigeki Sugii

Comprehensive Reviews in Food Science and Food Safety

To unravel the mechanism of human cellular reprogramming process at single-cell resolution, we pe... more To unravel the mechanism of human cellular reprogramming process at single-cell resolution, we performed parallel scRNA-Seq and scATAC-Seq analysis. Our analysis reveals that the cells undergoing reprogramming proceed in an asynchronous trajectory and diversify into heterogeneous sub-populations. BDD2-C8 fluorescent probe staining and negative staining for CD13, CD44 and CD201 markers, could enrich for the GDF3+ early reprogrammed cells. Combinatory usage of the surface markers enables the fine segregation of the early-intermediate cells with diverse reprogramming propensities. scATAC-Seq analysis further uncovered the genomic partitions and transcription factors responsible for the regulatory phasing of reprogramming process. Binary choice between a FOSL1 or a TEAD4-centric regulatory network determines the outcome of a successful reprogramming. Altogether, our study illuminates the multitude of diverse routes transversed by individual reprogramming cells and presents an integrativ...

Autophagy, Jan 13, 2018

The thyroid hormone triiodothyronine (T) activates thermogenesis by uncoupling electron transport... more The thyroid hormone triiodothyronine (T) activates thermogenesis by uncoupling electron transport from ATP synthesis in brown adipose tissue (BAT) mitochondria. Although T can induce thermogenesis by sympathetic innervation, little is known about its cell autonomous effects on BAT mitochondria. We thus examined effects of T on mitochondrial activity, autophagy, and metabolism in primary brown adipocytes and BAT and found that T increased fatty acid oxidation and mitochondrial respiration as well as autophagic flux, mitophagy, and mitochondrial biogenesis. Interestingly, there was no significant induction of intracellular reactive oxygen species (ROS) despite high mitochondrial respiration and UCP1 induction by T. However, when cells were treated with Atg5 siRNA to block autophagy, induction of mitochondrial respiration by T decreased, and was accompanied by ROS accumulation, demonstrating a critical role for autophagic mitochondrial turnover. We next generated an Atg5 conditional kn...

Stem cell research & therapy, Sep 29, 2017

Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to 'repr... more Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to 'reprogram' somatic cells to become induced pluripotent stem cells (iPSCs). Several microRNAs (miRNAs) are known to enhance reprogramming efficiency when co-expressed with the OSKM factors. The primate-specific chromosome 19 miRNA cluster (C19MC) is essential in primate reproduction, development, and differentiation. miR-524-5p, a C19MC member, is highly homologous to the reprogramming miR-520d-5p; we also reported that miR-524-5p was expressed in iPSCs but not mesenchymal stem cells (MSCs). This study aimed to elucidate possible contributions of miR-524-5p to the reprogramming process. A miR-524-5p precursor was introduced into human fibroblast HFF-1 in the presence of OSKM, and the relative number of embryonic stem cell (ESC)-like colonies that stained positively with alkaline phosphatase (AP) and Nanog were quantified to determine reprogramming efficiency. A miR-524-5p mimic was transf...

Journal of biomedical science, Jan 7, 2017

The human chromosome 19 miRNA cluster (C19MC) of 43 genes is a primate-specific miRNA cluster tha... more The human chromosome 19 miRNA cluster (C19MC) of 43 genes is a primate-specific miRNA cluster that may have biological significance in the genetic complexity of the primate. Despite previous reports on individual C19MC miRNA expression in cancer and stem cells, systematic studies on C19MC miRNA expression and biological functions are lacking. Cluster-wide C19MC miRNA expression profiling by microarray analysis showed wholesome C19MC activation in embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). However, in multipotent adipose-derived mesenchymal stem cells (MSCs) and a unipotent human white pre-adipocyte cell line, only selected C19MC miRNAs were expressed. MiRNA copy number analysis also showed selective C19MC expression in cancer cells with expression patterns highly similar to those in MSCs, suggesting similar miRNA regulatory mechanisms in these cells. Selective miRNA expression also suggests complex transcriptional mechanism(s) regulating C19MC expression...

Adipocyte, 2016

Retinoic acid (RA) is essential for early developmental processes and stem cell differentiation, ... more Retinoic acid (RA) is essential for early developmental processes and stem cell differentiation, but less is known about its contributions to adult tissues and stem cells including adipose tissue. We previously demonstrated that many genes involved in RA synthesis and downstream pathway are differentially expressed in adipose-derived stem cells (ASCs) from visceral fat compared to those from subcutaneous fat, leading to changes in their early adipogenic functions. In order to study potential contributions of RA in adipose tissue, we measured tissue RA levels using a technique based on surface-enhanced Raman spectroscopy (SERS). The data indicate heretofore underappreciated abundance of endogenous RA in mouse adipose tissue compared to other tissues and dynamic changes of RA concentrations after high fat diet feeding. Our results lay the foundation for further investigation on the functional role of RA in adipose tissue development and metabolism.

Diabetes, 2016

Increased visceral fat, rather than subcutaneous fat, during the onset of obesity is associated w... more Increased visceral fat, rather than subcutaneous fat, during the onset of obesity is associated with a higher risk of developing metabolic diseases. The inherent adipogenic properties of human adipose-derived stem cells (ASCs) from visceral depots are compromised compared with those of ASCs from subcutaneous depots, but little is known about the underlying mechanisms. Using ontological analysis of global gene expression studies, we demonstrate that many genes involved in retinoic acid (RA) synthesis or regulated by RA are differentially expressed in human tissues and ASCs from subcutaneous and visceral fat. The endogenous level of RA is higher in visceral ASCs; this is associated with upregulation of the RA synthesis gene through the visceral-specific developmental factor WT1. Excessive RA-mediated activity impedes the adipogenic capability of ASCs at early but not late stages of adipogenesis, which can be reversed by antagonism of RA receptors or knockdown of WT1. Our results revea...

Expert Reviews in Molecular Medicine, 2014

Adipose-derived stem cells (ASCs) are considered a great alternative source of mesenchymal stem c... more Adipose-derived stem cells (ASCs) are considered a great alternative source of mesenchymal stem cells (MSCs). Unlike bone marrow stem cells (BMSCs), ASCs can be retrieved in high numbers from lipoaspirate, a by-product of liposuction procedures. Given that ASCs represent an easily accessible and abundant source of multipotent cells, ASCs have garnered attention and curiosity from both scientific and clinical communities for their potential in clinical applications. Furthermore, their unique immunobiology and secretome are attractive therapeutic properties. A decade since the discovery of a stem cell reservoir residing within adipose tissue, ASC-based clinical trials have grown over the years around the world along with assessments made on their safety and efficacy. With the progress of ASCs into clinical applications, the aim towards producing clinical-grade ASCs becomes increasingly important. Several countries have recognised the growing industry of cell therapies and have develop...

Stem Cell Reports, 2014

Adipose-derived stem/stromal cells (ASCs) from the anatomically distinct subcutaneous and viscera... more Adipose-derived stem/stromal cells (ASCs) from the anatomically distinct subcutaneous and visceral depots of white adipose tissue (WAT) differ in their inherent properties. However, little is known about the molecular identity and definitive markers of ASCs from these depots. In this study, ASCs from subcutaneous fat (SC-ASCs) and visceral fat (VS-ASCs) of omental region were isolated and studied. High-content image screening of over 240 cell-surface markers identified several potential depot-specific markers of ASCs. Subsequent studies revealed consistent predominant expression of CD10 in SC-ASCs and CD200 in VS-ASCs across 12 human subjects and in mice. CD10-high-expressing cells sorted from SC-ASCs differentiated better than their CD10-low-expressing counterparts, whereas CD200-low VS-ASCs differentiated better than CD200-high VS-ASCs. The expression of CD10 and CD200 is thus depot-dependent and associates with adipogenic capacities. These markers will offer a valuable tool for tracking and screening of depot-specific stem cell populations.

The International Journal of Biochemistry & Cell Biology, 2013

Adipose-derived stem cells (ASCs) are the mesenchymal stem cell (MSC) population found in the str... more Adipose-derived stem cells (ASCs) are the mesenchymal stem cell (MSC) population found in the stromalvascular fraction (SVF) of fat tissue. White adipose tissue (WAT), with well-established roles in lipid storage and adipokine secretion, is advantageous over bone marrow as the source of MSCs due to relative abundance and ease of isolation of the tissue. ASCs reside perivascularly within WAT and physiologically undergo adipogenesis to support WAT expansion in response to increased energy intake. Apart from adipogenesis, ASCs can be induced in vitro to differentiate into osteoblasts, chondroblasts, myocytes, neurons and other cell types. ASCs can also be reprogrammed to induced pluripotent stem (iPS) cells more efficiently than other cell types. ASCs are immunoprivileged cells and secrete immunomodulatory, angiogenic, anti-apoptotic and haematopoietic factors that facilitate tissue repair. The multi-lineage differentiation capacity, unique immunobiological properties and secretome of ASCs offer tremendous therapeutic potentials in regenerative medicine.

Background Effective stem cell therapy is dependent on the stem cell quality that is determined b... more Background Effective stem cell therapy is dependent on the stem cell quality that is determined by their differentiation potential, impairment of which leads to poor engraftment and survival into the target cells. However, limitations in our understanding and the lack of reliable markers that can predict their maturation efficacies have hindered the development of stem cells as an effective therapeutic strategy. Our previous study identified CD10, a pro-adipogenic, depot-specific prospective cell surface marker of human adipose-derived stem cells (ASCs). Here, we aim to determine if CD10 can be used as a prospective marker to predict mature adipocyte quality and play a direct role in adipocyte maturation. Methods We first generated 14 primary human subject-derived ASCs and stable immortalized CD10 knockdown and overexpression lines for 4 subjects by the lentiviral transduction system. To evaluate the role of CD10 in adipogenesis, the adipogenic potential of the human subject samples...

Stem Cell Research & Therapy

Background Despite recent rapid progress in method development and biological understanding of in... more Background Despite recent rapid progress in method development and biological understanding of induced pluripotent stem (iPS) cells, there has been a relative shortage of tools that monitor the early reprogramming process into human iPS cells. Methods We screened the in-house built fluorescent library compounds that specifically bind human iPS cells. After tertiary screening, the selected probe was analyzed for its ability to detect reprogramming cells in the time-dependent manner using high-content imaging analysis. The probe was compared with conventional dyes in different reprogramming methods, cell types, and cell culture conditions. Cell sorting was performed with the fluorescent probe to analyze the early reprogramming cells for their pluripotent characteristics and genome-wide gene expression signatures by RNA-seq. Finally, the candidate reprogramming factor identified was investigated for its ability to modulate reprogramming efficiency. Results We identified a novel BODIPY-...

Advances in Magnetic Resonance Technology and Applications

International Journal of Biological Macromolecules

This article illustrates a relatively less charted form of exilic dislocation which I have dubbed... more This article illustrates a relatively less charted form of exilic dislocation which I have dubbed paraexile. Unlike Claudio Guillén, who claims that exiled writers can triumph over their native attachments and create a literature of "counter-exile," I propose, alongside critics like Lamming, Rushdie, or Said, that the trauma of displacement can never be entirely left behind and is constantly part of exilic writing. In addition, I make the claim that paraexilic literature is a peculiar form of internalizing exile by means of irony and contradiction. I am illustrating this attitude with the work of Constantin Noica, one of the most popular and respected philosophers in postwar Romania, who rejected emigration and, instead, adopted the paradoxical solution of triumphing over internal and internalized exile by embracing it as a form of liberation. I am proposing the rhetorical category of contra-discourse-a dialogic structure of argument and narrative in which the homely and the foreign are spoken of in the ironically mingled voices of the oppressor and of the victim. I am concluding with the suggestion that, while the work of Noica is in many ways idiosyncratic, it may also be viewed as a typical form of coping with exilic traumas in Central and East European cultures during communism.

Diabetes

Obesity has reached pandemic proportions in the developed world. The discovery that white adipocy... more Obesity has reached pandemic proportions in the developed world. The discovery that white adipocytes have the capacity to undergo browning to become metabolically-active beige cells has generated significant interest in the field of metabolic medicine. However, the study of adipose tissue browning has been hampered by a lack of imaging modalities that permit longitudinal and non-invasive monitoring of this process. To this end, we designed near infra-red (NIR) fluorescence protein iRFP720-Ucp1 reporter construct, in which the expression of iRFP720 is driven by a mini UCP1 promoter. Non-invasive assessment of adipose beiging during adrenergic stimulation was performed by viral transduction of mouse white adipocytes, followed by multi-spectral optoacoustic imaging technology with ultrasound tomography (MSOT-US). We observed increased iRFP720 fluorescence coupled with attenuated lipid signals upon stimulation. As proof of concept, we validated our approach against the hybrid positron e...

Stem Cell Research & Therapy

Background: Visceral (VS) fat depot is known to have defective adipogenic functions compared to s... more Background: Visceral (VS) fat depot is known to have defective adipogenic functions compared to subcutaneous (SC) fat, but its mechanism of origin is unclear. Objective: We tested our hypothesis that the degree of oxidative stress in adipose-derived stem cells (ASCs) from these depots may account for this difference. Methods: ASCs were isolated from VS (omental region) and SC (abdominal region) fat depots of human subjects undergoing bariatric surgery. ASCs from VS and SC fat were investigated for their cellular characteristics in reactive oxygen species (ROS), metabolism, gene expression, proliferation, senescence, migration, and adipocyte differentiation. ASCs were also treated with antioxidant ascorbic acid (vitamin C). Results: We found that human VS-derived ASCs exhibit excessive oxidative stress characterized by high reactive oxygen species (ROS), compared to SC-derived ASCs. Gene expression analyses indicate that the VS-ASCs exhibit higher levels of genes involved in pro-oxidant and pro-inflammatory pathways and lower levels of genes in antioxidant and anti-inflammatory pathways. VS-ASCs have impaired cellular functions compared to SC-ASCs, such as slower proliferation, early senescence, less migratory activity, and poor adipogenic capability in vitro. Treatment with ascorbic acid decreased ROS levels drastically in VS-ASCs. Ascorbic acid treatment substantially improved proliferation, senescence, migration, and adipogenic capacities of compromised ASCs caused by high ROS. Conclusions: This finding suggests the fat depot-specific differences of cellular defects originating from stem cell population. Considering clinical potentials of human ASCs for cell therapies, this also offers a possible strategy for improving their therapeutic qualities through antioxidants.

Stem Cell Research & Therapy

Adipogenesis is essential in in vitro experimentation to assess differentiation capability of ste... more Adipogenesis is essential in in vitro experimentation to assess differentiation capability of stem cells, and therefore, its accurate measurement is important. Quantitative analysis of adipogenic levels, however, is challenging and often susceptible to errors due to non-specific reading or manual estimation by observers. To this end, we developed a novel adipocyte quantification algorithm, named Fast Adipogenesis Tracking System (FATS), based on computer vision libraries. The FATS algorithm is versatile and capable of accurately detecting and quantifying percentage of cells undergoing adipogenic and browning differentiation even under difficult conditions such as the presence of large cell clumps or high cell densities. The algorithm was tested on various cell lines including 3T3-L1 cells, adiposederived mesenchymal stem cells (ASCs), and induced pluripotent stem cell (iPSC)-derived cells. The FATS algorithm is particularly useful for adipogenic measurement of embryoid bodies derived from pluripotent stem cells and was capable of accurately distinguishing adipogenic cells from false-positive stains. We then demonstrate the effectiveness of the FATS algorithm for screening of nuclear receptor ligands that affect adipogenesis in the high-throughput manner. Together, the FATS offer a universal and automated image-based method to quantify adipocyte differentiation of different cell lines in both standard and high-throughput workflows.

A Roadmap to Non-Hematopoietic Stem Cell-based Therapeutics

Abstract Advances in the development of mesenchymal stem cells (MSCs) for clinical applications, ... more Abstract Advances in the development of mesenchymal stem cells (MSCs) for clinical applications, especially in cases where therapies are presently lacking, have provided new hope for many patients. In this chapter, we review the potential use of MSCs as biological drugs, and discuss several challenges that must be addressed to achieve better therapeutic outcomes. For example, (1) MSC populations are heterogeneous and vary in differentiation potential depending upon stages, (2) each disease progresses through stages that have differences in relative responsiveness to MSC therapy, (3) each disease requires targeted delivery, optimized dose, and homing of MSCs to maximize therapeutic potential, and (4) MSCs achieve their therapeutic effects via multiple complex mechanisms that must be elucidated to maximize their efficacy. In addition, we draw upon lessons learned from preclinical/clinical testing of drug-based therapies, and anticipate that knowledge gleaned during development of synthetic drugs will be of great value in addressing challenges currently facing the development of MSC-based therapies.

Journal of biophotonics, Jan 5, 2018

White adipose tissue (WAT) and brown adipose tissue (BAT) biologically function in an opposite wa... more White adipose tissue (WAT) and brown adipose tissue (BAT) biologically function in an opposite way in energy metabolism. BAT induces energy consumption by heat production while WAT mainly stores energy in the form of triglycerides. Recent progress in the conversion of WAT cells to "beige" or "brown-like" adipocytes in animals, having functional similarity to BAT, spurred a great interest in developing the next-generation therapeutics in the field of metabolic disorders. Though magnetic resonance imaging and positron emission tomography could detect classical BAT and WAT in animals and humans, it is of a great challenge in detecting the "browning" process in vivo. Here, to the best of our knowledge, for the first time, we present a simple, cost-effective, label-free fiber optic-based diffuse reflectance spectroscopy measurement in the near infrared II window (~1050-1400 nm) for the quantitative detection of browning in a mouse model in vivo. We could suc...

Comprehensive Reviews in Food Science and Food Safety

To unravel the mechanism of human cellular reprogramming process at single-cell resolution, we pe... more To unravel the mechanism of human cellular reprogramming process at single-cell resolution, we performed parallel scRNA-Seq and scATAC-Seq analysis. Our analysis reveals that the cells undergoing reprogramming proceed in an asynchronous trajectory and diversify into heterogeneous sub-populations. BDD2-C8 fluorescent probe staining and negative staining for CD13, CD44 and CD201 markers, could enrich for the GDF3+ early reprogrammed cells. Combinatory usage of the surface markers enables the fine segregation of the early-intermediate cells with diverse reprogramming propensities. scATAC-Seq analysis further uncovered the genomic partitions and transcription factors responsible for the regulatory phasing of reprogramming process. Binary choice between a FOSL1 or a TEAD4-centric regulatory network determines the outcome of a successful reprogramming. Altogether, our study illuminates the multitude of diverse routes transversed by individual reprogramming cells and presents an integrativ...

Autophagy, Jan 13, 2018

The thyroid hormone triiodothyronine (T) activates thermogenesis by uncoupling electron transport... more The thyroid hormone triiodothyronine (T) activates thermogenesis by uncoupling electron transport from ATP synthesis in brown adipose tissue (BAT) mitochondria. Although T can induce thermogenesis by sympathetic innervation, little is known about its cell autonomous effects on BAT mitochondria. We thus examined effects of T on mitochondrial activity, autophagy, and metabolism in primary brown adipocytes and BAT and found that T increased fatty acid oxidation and mitochondrial respiration as well as autophagic flux, mitophagy, and mitochondrial biogenesis. Interestingly, there was no significant induction of intracellular reactive oxygen species (ROS) despite high mitochondrial respiration and UCP1 induction by T. However, when cells were treated with Atg5 siRNA to block autophagy, induction of mitochondrial respiration by T decreased, and was accompanied by ROS accumulation, demonstrating a critical role for autophagic mitochondrial turnover. We next generated an Atg5 conditional kn...

Stem cell research & therapy, Sep 29, 2017

Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to 'repr... more Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to 'reprogram' somatic cells to become induced pluripotent stem cells (iPSCs). Several microRNAs (miRNAs) are known to enhance reprogramming efficiency when co-expressed with the OSKM factors. The primate-specific chromosome 19 miRNA cluster (C19MC) is essential in primate reproduction, development, and differentiation. miR-524-5p, a C19MC member, is highly homologous to the reprogramming miR-520d-5p; we also reported that miR-524-5p was expressed in iPSCs but not mesenchymal stem cells (MSCs). This study aimed to elucidate possible contributions of miR-524-5p to the reprogramming process. A miR-524-5p precursor was introduced into human fibroblast HFF-1 in the presence of OSKM, and the relative number of embryonic stem cell (ESC)-like colonies that stained positively with alkaline phosphatase (AP) and Nanog were quantified to determine reprogramming efficiency. A miR-524-5p mimic was transf...

Journal of biomedical science, Jan 7, 2017

The human chromosome 19 miRNA cluster (C19MC) of 43 genes is a primate-specific miRNA cluster tha... more The human chromosome 19 miRNA cluster (C19MC) of 43 genes is a primate-specific miRNA cluster that may have biological significance in the genetic complexity of the primate. Despite previous reports on individual C19MC miRNA expression in cancer and stem cells, systematic studies on C19MC miRNA expression and biological functions are lacking. Cluster-wide C19MC miRNA expression profiling by microarray analysis showed wholesome C19MC activation in embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). However, in multipotent adipose-derived mesenchymal stem cells (MSCs) and a unipotent human white pre-adipocyte cell line, only selected C19MC miRNAs were expressed. MiRNA copy number analysis also showed selective C19MC expression in cancer cells with expression patterns highly similar to those in MSCs, suggesting similar miRNA regulatory mechanisms in these cells. Selective miRNA expression also suggests complex transcriptional mechanism(s) regulating C19MC expression...

Adipocyte, 2016

Retinoic acid (RA) is essential for early developmental processes and stem cell differentiation, ... more Retinoic acid (RA) is essential for early developmental processes and stem cell differentiation, but less is known about its contributions to adult tissues and stem cells including adipose tissue. We previously demonstrated that many genes involved in RA synthesis and downstream pathway are differentially expressed in adipose-derived stem cells (ASCs) from visceral fat compared to those from subcutaneous fat, leading to changes in their early adipogenic functions. In order to study potential contributions of RA in adipose tissue, we measured tissue RA levels using a technique based on surface-enhanced Raman spectroscopy (SERS). The data indicate heretofore underappreciated abundance of endogenous RA in mouse adipose tissue compared to other tissues and dynamic changes of RA concentrations after high fat diet feeding. Our results lay the foundation for further investigation on the functional role of RA in adipose tissue development and metabolism.

Diabetes, 2016

Increased visceral fat, rather than subcutaneous fat, during the onset of obesity is associated w... more Increased visceral fat, rather than subcutaneous fat, during the onset of obesity is associated with a higher risk of developing metabolic diseases. The inherent adipogenic properties of human adipose-derived stem cells (ASCs) from visceral depots are compromised compared with those of ASCs from subcutaneous depots, but little is known about the underlying mechanisms. Using ontological analysis of global gene expression studies, we demonstrate that many genes involved in retinoic acid (RA) synthesis or regulated by RA are differentially expressed in human tissues and ASCs from subcutaneous and visceral fat. The endogenous level of RA is higher in visceral ASCs; this is associated with upregulation of the RA synthesis gene through the visceral-specific developmental factor WT1. Excessive RA-mediated activity impedes the adipogenic capability of ASCs at early but not late stages of adipogenesis, which can be reversed by antagonism of RA receptors or knockdown of WT1. Our results revea...

Expert Reviews in Molecular Medicine, 2014

Adipose-derived stem cells (ASCs) are considered a great alternative source of mesenchymal stem c... more Adipose-derived stem cells (ASCs) are considered a great alternative source of mesenchymal stem cells (MSCs). Unlike bone marrow stem cells (BMSCs), ASCs can be retrieved in high numbers from lipoaspirate, a by-product of liposuction procedures. Given that ASCs represent an easily accessible and abundant source of multipotent cells, ASCs have garnered attention and curiosity from both scientific and clinical communities for their potential in clinical applications. Furthermore, their unique immunobiology and secretome are attractive therapeutic properties. A decade since the discovery of a stem cell reservoir residing within adipose tissue, ASC-based clinical trials have grown over the years around the world along with assessments made on their safety and efficacy. With the progress of ASCs into clinical applications, the aim towards producing clinical-grade ASCs becomes increasingly important. Several countries have recognised the growing industry of cell therapies and have develop...

Stem Cell Reports, 2014

Adipose-derived stem/stromal cells (ASCs) from the anatomically distinct subcutaneous and viscera... more Adipose-derived stem/stromal cells (ASCs) from the anatomically distinct subcutaneous and visceral depots of white adipose tissue (WAT) differ in their inherent properties. However, little is known about the molecular identity and definitive markers of ASCs from these depots. In this study, ASCs from subcutaneous fat (SC-ASCs) and visceral fat (VS-ASCs) of omental region were isolated and studied. High-content image screening of over 240 cell-surface markers identified several potential depot-specific markers of ASCs. Subsequent studies revealed consistent predominant expression of CD10 in SC-ASCs and CD200 in VS-ASCs across 12 human subjects and in mice. CD10-high-expressing cells sorted from SC-ASCs differentiated better than their CD10-low-expressing counterparts, whereas CD200-low VS-ASCs differentiated better than CD200-high VS-ASCs. The expression of CD10 and CD200 is thus depot-dependent and associates with adipogenic capacities. These markers will offer a valuable tool for tracking and screening of depot-specific stem cell populations.

The International Journal of Biochemistry & Cell Biology, 2013

Adipose-derived stem cells (ASCs) are the mesenchymal stem cell (MSC) population found in the str... more Adipose-derived stem cells (ASCs) are the mesenchymal stem cell (MSC) population found in the stromalvascular fraction (SVF) of fat tissue. White adipose tissue (WAT), with well-established roles in lipid storage and adipokine secretion, is advantageous over bone marrow as the source of MSCs due to relative abundance and ease of isolation of the tissue. ASCs reside perivascularly within WAT and physiologically undergo adipogenesis to support WAT expansion in response to increased energy intake. Apart from adipogenesis, ASCs can be induced in vitro to differentiate into osteoblasts, chondroblasts, myocytes, neurons and other cell types. ASCs can also be reprogrammed to induced pluripotent stem (iPS) cells more efficiently than other cell types. ASCs are immunoprivileged cells and secrete immunomodulatory, angiogenic, anti-apoptotic and haematopoietic factors that facilitate tissue repair. The multi-lineage differentiation capacity, unique immunobiological properties and secretome of ASCs offer tremendous therapeutic potentials in regenerative medicine.

Background Effective stem cell therapy is dependent on the stem cell quality that is determined b... more Background Effective stem cell therapy is dependent on the stem cell quality that is determined by their differentiation potential, impairment of which leads to poor engraftment and survival into the target cells. However, limitations in our understanding and the lack of reliable markers that can predict their maturation efficacies have hindered the development of stem cells as an effective therapeutic strategy. Our previous study identified CD10, a pro-adipogenic, depot-specific prospective cell surface marker of human adipose-derived stem cells (ASCs). Here, we aim to determine if CD10 can be used as a prospective marker to predict mature adipocyte quality and play a direct role in adipocyte maturation. Methods We first generated 14 primary human subject-derived ASCs and stable immortalized CD10 knockdown and overexpression lines for 4 subjects by the lentiviral transduction system. To evaluate the role of CD10 in adipogenesis, the adipogenic potential of the human subject samples...

Stem Cell Research & Therapy

Background Despite recent rapid progress in method development and biological understanding of in... more Background Despite recent rapid progress in method development and biological understanding of induced pluripotent stem (iPS) cells, there has been a relative shortage of tools that monitor the early reprogramming process into human iPS cells. Methods We screened the in-house built fluorescent library compounds that specifically bind human iPS cells. After tertiary screening, the selected probe was analyzed for its ability to detect reprogramming cells in the time-dependent manner using high-content imaging analysis. The probe was compared with conventional dyes in different reprogramming methods, cell types, and cell culture conditions. Cell sorting was performed with the fluorescent probe to analyze the early reprogramming cells for their pluripotent characteristics and genome-wide gene expression signatures by RNA-seq. Finally, the candidate reprogramming factor identified was investigated for its ability to modulate reprogramming efficiency. Results We identified a novel BODIPY-...

Advances in Magnetic Resonance Technology and Applications

International Journal of Biological Macromolecules

This article illustrates a relatively less charted form of exilic dislocation which I have dubbed... more This article illustrates a relatively less charted form of exilic dislocation which I have dubbed paraexile. Unlike Claudio Guillén, who claims that exiled writers can triumph over their native attachments and create a literature of "counter-exile," I propose, alongside critics like Lamming, Rushdie, or Said, that the trauma of displacement can never be entirely left behind and is constantly part of exilic writing. In addition, I make the claim that paraexilic literature is a peculiar form of internalizing exile by means of irony and contradiction. I am illustrating this attitude with the work of Constantin Noica, one of the most popular and respected philosophers in postwar Romania, who rejected emigration and, instead, adopted the paradoxical solution of triumphing over internal and internalized exile by embracing it as a form of liberation. I am proposing the rhetorical category of contra-discourse-a dialogic structure of argument and narrative in which the homely and the foreign are spoken of in the ironically mingled voices of the oppressor and of the victim. I am concluding with the suggestion that, while the work of Noica is in many ways idiosyncratic, it may also be viewed as a typical form of coping with exilic traumas in Central and East European cultures during communism.

Diabetes

Obesity has reached pandemic proportions in the developed world. The discovery that white adipocy... more Obesity has reached pandemic proportions in the developed world. The discovery that white adipocytes have the capacity to undergo browning to become metabolically-active beige cells has generated significant interest in the field of metabolic medicine. However, the study of adipose tissue browning has been hampered by a lack of imaging modalities that permit longitudinal and non-invasive monitoring of this process. To this end, we designed near infra-red (NIR) fluorescence protein iRFP720-Ucp1 reporter construct, in which the expression of iRFP720 is driven by a mini UCP1 promoter. Non-invasive assessment of adipose beiging during adrenergic stimulation was performed by viral transduction of mouse white adipocytes, followed by multi-spectral optoacoustic imaging technology with ultrasound tomography (MSOT-US). We observed increased iRFP720 fluorescence coupled with attenuated lipid signals upon stimulation. As proof of concept, we validated our approach against the hybrid positron e...

Stem Cell Research & Therapy

Background: Visceral (VS) fat depot is known to have defective adipogenic functions compared to s... more Background: Visceral (VS) fat depot is known to have defective adipogenic functions compared to subcutaneous (SC) fat, but its mechanism of origin is unclear. Objective: We tested our hypothesis that the degree of oxidative stress in adipose-derived stem cells (ASCs) from these depots may account for this difference. Methods: ASCs were isolated from VS (omental region) and SC (abdominal region) fat depots of human subjects undergoing bariatric surgery. ASCs from VS and SC fat were investigated for their cellular characteristics in reactive oxygen species (ROS), metabolism, gene expression, proliferation, senescence, migration, and adipocyte differentiation. ASCs were also treated with antioxidant ascorbic acid (vitamin C). Results: We found that human VS-derived ASCs exhibit excessive oxidative stress characterized by high reactive oxygen species (ROS), compared to SC-derived ASCs. Gene expression analyses indicate that the VS-ASCs exhibit higher levels of genes involved in pro-oxidant and pro-inflammatory pathways and lower levels of genes in antioxidant and anti-inflammatory pathways. VS-ASCs have impaired cellular functions compared to SC-ASCs, such as slower proliferation, early senescence, less migratory activity, and poor adipogenic capability in vitro. Treatment with ascorbic acid decreased ROS levels drastically in VS-ASCs. Ascorbic acid treatment substantially improved proliferation, senescence, migration, and adipogenic capacities of compromised ASCs caused by high ROS. Conclusions: This finding suggests the fat depot-specific differences of cellular defects originating from stem cell population. Considering clinical potentials of human ASCs for cell therapies, this also offers a possible strategy for improving their therapeutic qualities through antioxidants.

Stem Cell Research & Therapy

Adipogenesis is essential in in vitro experimentation to assess differentiation capability of ste... more Adipogenesis is essential in in vitro experimentation to assess differentiation capability of stem cells, and therefore, its accurate measurement is important. Quantitative analysis of adipogenic levels, however, is challenging and often susceptible to errors due to non-specific reading or manual estimation by observers. To this end, we developed a novel adipocyte quantification algorithm, named Fast Adipogenesis Tracking System (FATS), based on computer vision libraries. The FATS algorithm is versatile and capable of accurately detecting and quantifying percentage of cells undergoing adipogenic and browning differentiation even under difficult conditions such as the presence of large cell clumps or high cell densities. The algorithm was tested on various cell lines including 3T3-L1 cells, adiposederived mesenchymal stem cells (ASCs), and induced pluripotent stem cell (iPSC)-derived cells. The FATS algorithm is particularly useful for adipogenic measurement of embryoid bodies derived from pluripotent stem cells and was capable of accurately distinguishing adipogenic cells from false-positive stains. We then demonstrate the effectiveness of the FATS algorithm for screening of nuclear receptor ligands that affect adipogenesis in the high-throughput manner. Together, the FATS offer a universal and automated image-based method to quantify adipocyte differentiation of different cell lines in both standard and high-throughput workflows.

A Roadmap to Non-Hematopoietic Stem Cell-based Therapeutics

Abstract Advances in the development of mesenchymal stem cells (MSCs) for clinical applications, ... more Abstract Advances in the development of mesenchymal stem cells (MSCs) for clinical applications, especially in cases where therapies are presently lacking, have provided new hope for many patients. In this chapter, we review the potential use of MSCs as biological drugs, and discuss several challenges that must be addressed to achieve better therapeutic outcomes. For example, (1) MSC populations are heterogeneous and vary in differentiation potential depending upon stages, (2) each disease progresses through stages that have differences in relative responsiveness to MSC therapy, (3) each disease requires targeted delivery, optimized dose, and homing of MSCs to maximize therapeutic potential, and (4) MSCs achieve their therapeutic effects via multiple complex mechanisms that must be elucidated to maximize their efficacy. In addition, we draw upon lessons learned from preclinical/clinical testing of drug-based therapies, and anticipate that knowledge gleaned during development of synthetic drugs will be of great value in addressing challenges currently facing the development of MSC-based therapies.

Journal of biophotonics, Jan 5, 2018

White adipose tissue (WAT) and brown adipose tissue (BAT) biologically function in an opposite wa... more White adipose tissue (WAT) and brown adipose tissue (BAT) biologically function in an opposite way in energy metabolism. BAT induces energy consumption by heat production while WAT mainly stores energy in the form of triglycerides. Recent progress in the conversion of WAT cells to "beige" or "brown-like" adipocytes in animals, having functional similarity to BAT, spurred a great interest in developing the next-generation therapeutics in the field of metabolic disorders. Though magnetic resonance imaging and positron emission tomography could detect classical BAT and WAT in animals and humans, it is of a great challenge in detecting the "browning" process in vivo. Here, to the best of our knowledge, for the first time, we present a simple, cost-effective, label-free fiber optic-based diffuse reflectance spectroscopy measurement in the near infrared II window (~1050-1400 nm) for the quantitative detection of browning in a mouse model in vivo. We could suc...