Jieun Lee, PhD is a research associate in the Orthopaedic Surgery Department at Stanford University School of Medicine.
Dr. Lee earned her PhD degree at Yonsei University in Seoul, Korea. In her most significant scientific accomplishments as a PhD student, she elucidated the therapeutic potential of pancreatic progenitor cells, demonstrating how GLP-1-expressing adult pancreatic precursor cells reverse diabetes in STZ-induced diabetic rats (Lee et al., Stem Cells and Development 2009).
Dr. Lee continued stem cell research as a postdoctoral fellow at Stanford University where she lead a project generating safe and efficient human inducible pluripotent stem cells (iPSCs) from somatic cells (Yang et al., Protein Expression Purification, 2011 and Yang et al., Biotechnology Bioengineering, 2009) in John Cooke’s lab in the Department of Cardiovascular Medicine. In her most significant scientific accomplishments as a postdoc, firstly, she found the activation of innate immunity via Toll-like receptor 3 (TLR3) is required for nuclear reprogramming (Lee et al., Cell 2012). It was the first discovery to provide insight on the role of inflammatory mechanism in reprogramming, which has subsequently applied this mechanism to convert human fibroblasts into functional endothelial cells by activating TLR3 (Sayed et al., Circulation 2014).
Currently in Nidhi Bhutani's lab in the Department of Orthopaedic Surgery at Stanford, Dr. Lee has developed an efficient and well-defined chondrogenic differentiation protocol from human iPSCs to generate cartilage tissue in perspective of clinical application for Osteoarthritis (OA) patients and focal cartilage defects (Lee et al., The FASEB J 2015).
Honors & Awards
Scholarship/Grant from Brain Korea 21 Project, Yonsei University, Korea (2000-2006)
Postdoctoral fellowship award, TRDRP, University of California (2009)
Junior Investigator Poster Award, International Society for Stem Cell Research (ISSCR) (2012)
Early induction of a prechondrogenic population allows efficient generation of stable chondrocytes from human induced pluripotent stem cells
2015; 29 (8): 3399-3410
Regeneration of human cartilage is inherently inefficient; an abundant autologous source, such as human induced pluripotent stem cells (hiPSCs), is therefore attractive for engineering cartilage. We report a growth factor-based protocol for differentiating hiPSCs into articular-like chondrocytes (hiChondrocytes) within 2 weeks, with an overall efficiency >90%. The hiChondrocytes are stable and comparable to adult articular chondrocytes in global gene expression, extracellular matrix production, and ability to generate cartilage tissue in vitro and in immune-deficient mice. Molecular characterization identified an early SRY (sex-determining region Y) box (Sox)9(low) cluster of differentiation (CD)44(low)CD140(low) prechondrogenic population during hiPSC differentiation. In addition, 2 distinct Sox9-regulated gene networks were identified in the Sox9(low) and Sox9(high) populations providing novel molecular insights into chondrogenic fate commitment and differentiation. Our findings present a favorable method for generating hiPSC-derived articular-like chondrocytes. The hiChondrocytes are an attractive cell source for cartilage engineering because of their abundance, autologous nature, and potential to generate articular-like cartilage rather than fibrocartilage. In addition, hiChondrocytes can be excellent tools for modeling human musculoskeletal diseases in a dish and for rapid drug screening.-Lee, J., Taylor, S. E. B., Smeriglio, P., Lai, J., Maloney, W. J., Yang, F., Bhutani, N. Early induction of a prechondrogenic population allows efficient generation of stable chondrocytes from human induced pluripotent stem cells.
View details for DOI 10.1096/fj.14-269720
View details for Web of Science ID 000358796900027
Activation of Innate Immunity Is Required for Efficient Nuclear Reprogramming
2012; 151 (3): 547-558
Retroviral overexpression of reprogramming factors (Oct4, Sox2, Klf4, c-Myc) generates induced pluripotent stem cells (iPSCs). However, the integration of foreign DNA could induce genomic dysregulation. Cell-permeant proteins (CPPs) could overcome this limitation. To date, this approach has proved exceedingly inefficient. We discovered a striking difference in the pattern of gene expression induced by viral versus CPP-based delivery of the reprogramming factors, suggesting that a signaling pathway required for efficient nuclear reprogramming was activated by the retroviral, but not CPP approach. In gain- and loss-of-function studies, we find that the toll-like receptor 3 (TLR3) pathway enables efficient induction of pluripotency by viral or mmRNA approaches. Stimulation of TLR3 causes rapid and global changes in the expression of epigenetic modifiers to enhance chromatin remodeling and nuclear reprogramming. Activation of inflammatory pathways are required for efficient nuclear reprogramming in the induction of pluripotency.
View details for DOI 10.1016/j.cell.2012.09.034
View details for Web of Science ID 000310529300012
View details for PubMedID 23101625
Reversal of Diabetes in Rats Using GLP-1-Expressing Adult Pancreatic Duct-Like Precursor Cells Transformed From Acinar to Ductal Cells
STEM CELLS AND DEVELOPMENT
2009; 18 (7): 991-1001
Pancreatic injury induces replacement of exocrine acinar cells with ductal cells. These ductal cells have the potential to regenerate the pancreas, but their origin still remains unknown. It has been reported that adult pancreatic acinar cells have the potential to transdifferentiate to ductal progenitor cells. In this regards, we established novel adult pancreatic duct-like progenitor cell lines YGIC4 and YGIC5 and assessed the usefulness of these ductal progenitors in the cell therapy of diabetic rats. Acinar cells were cultured from pancreata of male Sprague Dawley rats and gradually attained ductal cell characteristics, such as expression of CK19 and CFTR with a concomitant down-regulation of amylase expression over time, suggesting transdifferentiation from acinar to ductal cells. During cell culture, the expression of Pdx-1, c-Kit, and vimentin peaked and then decreased, suggesting that transdifferentiation recapitulated embryogenesis. Overexpression of pancreas development regulatory genes and CK19, as well as the ability to differentiate into insulin-producing cells, suggests that the YGIC5 cells had characteristics of pancreatic progenitor cells. Finally, YGIC5 cells coexpressing Green fluorescent protein (GFP) and glucagon-like peptide (GLP)-1 under the activation of a zinc-inducible metallothionein promoter were intravenously infused to STZ-induced diabetic rats. Hyperglycemia was ameliorated with elevation of plasma insulin, and GFP-positive donor cells were colocalized in the acinar and islet areas of recipient pancreata following zinc treatment. In conclusion, after establishing pancreatic progenitor cell lines YGIC4 and YGIC5 under the concept of acinar to ductal transdifferentiation in vitro, we demonstrate how these adult pancreatic stem/progenitor cells can be used to regulate adult pancreatic differentiation toward developing therapy for pancreatic disease such as diabetes mellitus.
View details for DOI 10.1089/scd.2008.0107
View details for Web of Science ID 000269701000005
View details for PubMedID 19125629
Transdifferentiation of human fibroblasts to endothelial cells: role of innate immunity.
2015; 131 (3): 300-309
-Cell fate is fluid, and may be altered experimentally by the forced expression of master regulators mediating cell lineage. Such reprogramming has been achieved using viral vectors encoding transcription factors. We recently discovered that the viral vectors are more than passive vehicles for transcription factors, as they participate actively in the process of nuclear reprogramming to pluripotency by increasing epigenetic plasticity. Based on this recognition, we hypothesized that small molecule activators of toll-like receptor 3 (TLR3), together with external microenvironmental cues that drive EC specification, might be sufficient to induce transdifferentiation of fibroblasts into ECs (iECs).-We show that TLR3 agonist Poly I:C, combined with exogenous EC growth factors, transdifferentiated human fibroblasts into ECs. These iECs were comparable to HMVEC in immunohistochemical, genetic and functional assays, including the ability to form capillary-like structures and to incorporate acetylated-LDL. Furthermore, iECs significantly improved limb perfusion and neovascularization in the murine ischemic hindlimb. Finally, using genetic knockdown studies, we find that the effective transdifferentiation of human fibroblasts to endothelial cells requires innate immune activation.-This study suggests that manipulation of innate immune signaling may be generally used to modify cell fate. As similar signaling pathways are activated by damage associated molecular patterns, epigenetic plasticity induced by innate immunity may play a fundamental role in transdifferentiation during wound healing and regeneration. Finally, this study is a first step toward development of a small molecule strategy for therapeutic transdifferentiation for vascular disease.
View details for DOI 10.1161/CIRCULATIONAHA.113.007394
View details for PubMedID 25359165
Nicotine and pathological angiogenesis
2012; 91 (21-22): 1058-1064
This paper describes the role of endothelial nicotinic acetylcholine receptors (nAChR) in diseases where pathological angiogenesis plays a role. An extensive review of the literature was performed, focusing on studies that investigated the effect of nicotine upon angiogenesis. Nicotine induces pathological angiogenesis at clinically relevant concentrations (i.e. at tissue and plasma concentrations similar to those of a light to moderate smoker). Nicotine promotes endothelial cell migration, proliferation, survival, tube formation and nitric oxide (NO) production in vitro, mimicking the effect of other angiogenic growth factors. These in vitro findings indicate that there may be an angiogenic component to the pathophysiology of major tobacco related diseases such as carcinoma, atherosclerosis, and age-related macular degeneration. Indeed, nicotine stimulates pathological angiogenesis in pre-clinical models of these disorders. Subsequently, it has been demonstrated that nicotine stimulates nAChRs on the endothelium to induce angiogenic processes, that these nAChRs are largely of the ?7 homomeric type, and that there are synergistic interactions between the nAChRs and angiogenic growth factor receptors at the phosphoproteomic and genomic levels. These findings are of potential clinical relevance, and provide mechanistic insights into tobacco-related disease. Furthermore, these findings may lead to novel therapies for diseases characterized by insufficient or inappropriate angiogenesis.
View details for DOI 10.1016/j.lfs.2012.06.032
View details for Web of Science ID 000312119700019
View details for PubMedID 22796717
Solubility partner IF2 Domain I enables high yield synthesis of transducible transcription factors in Escherichia coli
PROTEIN EXPRESSION AND PURIFICATION
2011; 80 (1): 145-151
Since the discovery that somatic cells could be reprogrammed back to a pluripotent state through the viral expression of a certain set of transcription factors, there has been great interest in reprogramming using a safer and more clinically relevant protein-based approach. However, the search for an efficient reprogramming approach utilizing the transcription factors in protein form requires a significant amount of protein material. Milligram quantities of transcription factors are challenging to obtain due to low yields and poor solubility. In this work, we describe enhanced production of the pluripotency transcription factors Oct4, Sox2, Klf4, Nanog, and Lin28 after fusing them to a solubility partner, IF2 Domain I (IF2D1). We expressed and purified milligram quantities of the fusion proteins. Though the transcription factor passenger proteins became insoluble after removal of the IF2D1, the un-cleaved Oct4, Sox2, Klf4, and Nanog fusion proteins exhibited specific binding to their consensus DNA sequences. However, when we administered the un-cleaved IF2D1-Oct4-R9 and IF2D1-Sox2-R9 to fibroblasts and measured their ability to influence transcriptional activity, we found that they were not fully bioactive; IF2D1-Oct4-R9 and IF2D1-Sox2-R9 influenced only a subset of their downstream gene targets. Thus, while the IF2D1 solubility partner enabled soluble production of the fusion protein at high levels, it did not yield fully bioactive transcription factors.
View details for DOI 10.1016/j.pep.2011.06.017
View details for Web of Science ID 000295608800022
View details for PubMedID 21757009
- The role of nicotine in the pathogenesis of atherosclerosis ATHEROSCLEROSIS 2011; 215 (2): 281-283
Cell-Free Production of Transducible Transcription Factors for Nuclear Reprogramming
BIOTECHNOLOGY AND BIOENGINEERING
2009; 104 (6): 1047-1058
Ectopic expression of a defined set of transcription factors chosen from Oct3/4, Sox2, c-Myc, Klf4, Nanog, and Lin28 can directly reprogram somatic cells to pluripotency. These reprogrammed cells are referred to as induced pluripotent stem cells (iPSCs). To date, iPSCs have been successfully generated using lentiviruses, retroviruses, adenoviruses, plasmids, transposons, and recombinant proteins. Nucleic acid-based approaches raise concerns about genomic instability. In contrast, a protein-based approach for iPSC generation can avoid DNA integration concerns as well as provide greater control over the concentration, timing, and sequence of transcription factor stimulation. Researchers recently demonstrated that polyarginine peptide conjugation can deliver recombinant protein reprogramming factor (RF) cargoes into cells and reprogram somatic cells into iPSCs. However, the protein-based approach requires a significant amount of protein for the reprogramming process. Producing fusion RFs in the large amounts required for this approach using traditional heterologous in vivo production methods is difficult and cumbersome since toxicity, product aggregation, and proteolysis by endogenous proteases limit yields. In this work, we show that cell-free protein synthesis (CFPS) is a viable option for producing soluble and functional transducible transcription factors for nuclear reprogramming. We used an E. coli-based CFPS system to express the above set of six human RFs as fusion proteins, each with a nona-arginine (R9) protein transduction domain. Using the flexibility offered by the CFPS platform, we successfully addressed proteolysis and protein solubility problems to produce full-length and soluble R9-RF fusions. We subsequently showed that R9-Oct3/4, R9-Sox2, and R9-Nanog exhibit cognate DNA-binding activities, R9-Nanog translocates across the plasma and nuclear membranes, and R9-Sox2 exerts transcriptional activity on a known downstream gene target.
View details for DOI 10.1002/bit.22517
View details for Web of Science ID 000273813400001
View details for PubMedID 19718703
CXCL5 overexpression is associated with late stage gastric cancer
JOURNAL OF CANCER RESEARCH AND CLINICAL ONCOLOGY
2007; 133 (11): 835-840
Chemokines play multiple roles in the development and progression of many different tumors. Our cDNA array data suggested that chemokine CXCL5 was upregulated in gastric cancer. Here, we analyzed CXCL5 protein expression in gastric cancer and investigated the clinical implications of CXCL5 upregulation.Immunostaining for CXCL5 was performed on gastric tissue microarrays of tissue specimens obtained by gastrectomy. The intensity of immunostaining in tumor tissue was considered strong when tumor tissue staining was more intense than in normal tissue; the intensity was null when staining was weaker in the tumor than in normal tissue; and the intensity was weak when staining was similar in both tissues. Serum CXCL5 levels and microvascular density in tumor tissue were measured by ELISA and monoclonal antibody to Factor VIII.Strong CXCL5 expression correlated with tumor stage. CXCL5 expression did not correlate with T stage. However, N stage positively correlated with CXCL5 expression. Serum CXCL5 levels in late stage (IIIB, IV) gastric cancer patients were higher than in patients with benign conditions. Microvascular density was higher in tumors with strong CXCL5 expression, but the correlation with CXCL5 was not linear. Multiple logistic regression analyses showed that, compared to no or weak expression, strong expression of CXCL5 was a significant risk factor for high N stage (N2, N3).CXCL5 overexpression was associated with late stage gastric cancer and high N stage. These results suggest a role for CXCL5 in the progression of gastric cancer, specifically in lymph node metastasis.
View details for DOI 10.1007/s00432-007-0225-x
View details for Web of Science ID 000249315600005
View details for PubMedID 17479287