Adult Somatic Cells Research Articles

Chinmo is sufficient to induce male fate in somatic cells of the adult Drosophila ovary.

Sexual identity is continuously maintained in specific differentiated cell types long after sex determination occurs during development. In the adult Drosophila testis, the putative transcription factor Chronologically inappropriate morphogenesis (Chinmo) acts with the canonical male sex determinant DoublesexM (Dsx(M)) to maintain the male identity of somatic cyst stem cells and their progeny. Here we find that ectopic expression of chinmo is sufficient to induce a male identity in adult ovarian somatic cells, but it acts through a Dsx(M)-independent mechanism. Conversely, the feminization of the testis somatic stem cell lineage caused by loss of chinmo is enhanced by expression of the canonical female sex determinant Dsx(F), indicating that chinmo acts in parallel with the canonical sex determination pathway to maintain the male identity of testis somatic cells. Consistent with this finding, ectopic expression of female sex determinants in the adult testis disrupts tissue morphology. The miRNA let-7 downregulates chinmo in many contexts, and ectopic expression of let-7 in the adult testis is sufficient to recapitulate the chinmo loss-of-function phenotype, but we find no apparent phenotypes upon removal of let-7 in the adult ovary or testis. Our finding that chinmo is necessary and sufficient to promote a male identity in adult gonadal somatic cells suggests that the sexual identity of somatic cells can be reprogrammed in the adult Drosophila ovary as well as in the testis.

Biomedical Application of Dental Tissue-Derived Induced Pluripotent Stem Cells.

The academic researches and clinical applications in recent years found interest in induced pluripotent stem cells (iPSCs-) based regenerative medicine due to their pluripotency able to differentiate into any cell types in the body without using embryo. However, it is limited in generating iPSCs from adult somatic cells and use of these cells due to the low stem cell potency and donor site morbidity. In biomedical applications, particularly, dental tissue-derived iPSCs have been getting attention as a type of alternative sources for regenerating damaged tissues due to high potential of stem cell characteristics, easy accessibility and attainment, and their ectomesenchymal origin, which allow them to have potential for nerve, vessel, and dental tissue regeneration. This paper will cover the overview of dental tissue-derived iPSCs and their application with their advantages and drawbacks.

Adult stem cells as a tool for kidney regeneration.

Kidney regeneration is a challenging but promising strategy aimed at reducing the progression to end-stage renal disease (ESRD) and improving the quality of life of patients with ESRD. Adult stem cells are multipotent stem cells that reside in various tissues, such as bone marrow and adipose tissue. Although intensive studies to isolate kidney stem/progenitor cells from the adult kidney have been performed, it remains controversial whether stem/progenitor cells actually exist in the mammalian adult kidney. The efficacy of mesenchymal stem cells (MSCs) in the recovery of kidney function has been demonstrated in animal nephropathy models, such as acute tubular injury, glomerulonephritis, renal artery stenosis, and remnant kidney. However, their beneficial effects seem to be mediated largely via their paracrine effects rather than their direct differentiation into renal parenchymal cells. MSCs not only secrete bioactive molecules directly into the circulation, but they also release various molecules, such as proteins, mRNA, and microRNA, in membrane-covered vesicles. A detailed analysis of these molecules and an exploration of the optimal combination of these molecules will enable the treatment of patients with kidney disease without using stem cells. Another option for the treatment of patients with kidney disease using adult somatic cells is a direct/indirect reprogramming of adult somatic cells into kidney stem/progenitor cells. Although many hurdles still need to be overcome, this strategy will enable bona fide kidney regeneration rather than kidney repair using remnant renal parenchymal cells.

Positional memory of fibroblasts may affect efficiency of iPSC reprogramming

Induced Pluripotent Stem cells (iPSC) are pluripotent stem cells reprogrammed from adult somatic cells. Although iPSC hold great potential for applications in regenerative medicine, technical problems, mostly related to the low efficiency of reprogramming, are yet to be solved. Since the most used cells for iPSC reprogramming are skin fibroblasts (FB), and since FB preserve positional memory, we hypothesize that the anatomic origin of FB might influence iPSC reprogramming.We isolated FB from skin of five different sites (neck, arm, thigh, breast, abdomen) of 13 patients undergoing plastic surgery or from heart wall or ascending aorta wall of the explanted heart of 3 patients receiving heart transplantation. FB from different anatomic sites and control FB from neonatal foreskin, were cultured for one week to evaluate morphology, proliferation rate and proneness to apoptosis. Additionally, expression of vimentin, cadherin, smooth muscle actin and Factor VIII was investigated to exclude the presence of other cell types. Transcriptome analysis including genes involved in stemness maintenance, embryogenesis, cell growth, activation and development, was performed by real-time PCR. Despite the similar morphology of FB from different sites, and immunopositivity for vimentin, along with the absence of other cell type markers, FB isolated from abdomen and heart had 1.5-fold higher doubling time, while FB from heart, abdomen and breast were less susceptible to apoptosis. Intriguingly, Real-Time PCR revealed that in abdomen, breast, neck, arm and heart FB genes involved in cell growth, development, proliferation, and migration, as TM4SF1, GPC4, CSPG2, DDIT4, ID1 were up-regulated, while genes regulating embryogenesis and tissue morphogenesis, like VCAN, FN1, HOXA5, CD49a were up-regulated in FB isolated from abdomen, arm and heart. However, all FBs had transcripts of markers of Mesenchymal Stem Cells (MSC), as CD105 and CD90. Our results provide evidence that human adult FB from different sites have different genetic program. Therefore, FB may respond to reprogram technology in different manner, thus affecting reprogramming efficiency. While offering novel perspective of the reprogramming technology, our study also demonstrates that abdomen and breast FB share cardiac genetic signature of cardiac FB while expressing markers of MSC and they might represent the ideal cell for cardiac reprogramming.

High-Fidelity Reprogrammed Human IPSCs Have a High Efficacy of DNA Repair and Resemble hESCs in Their MYC Transcriptional Signature.

Human induced pluripotent stem cells (hiPSCs) are reprogrammed from adult or progenitor somatic cells and must make substantial adaptations to ensure genomic stability in order to become “embryonic stem cell- (ESC-) like.” The DNA damage response (DDR) is critical for maintenance of such genomic integrity. Herein, we determined whether cell of origin and reprogramming method influence the DDR of hiPSCs. We demonstrate that hiPSCs derived from cord blood (CB) myeloid progenitors (i.e., CB-iPSC) via an efficient high-fidelity stromal-activated (sa) method closely resembled hESCs in DNA repair gene expression signature and irradiation-induced DDR, relative to hiPSCs generated from CB or fibroblasts via standard methods. Furthermore, sa-CB-iPSCs also more closely resembled hESCs in accuracy of nonhomologous end joining (NHEJ), DNA double-strand break (DSB) repair, and C-MYC transcriptional signatures, relative to standard hiPSCs. Our data suggests that hiPSCs derived via more efficient reprogramming methods possess more hESC-like activated MYC signatures and DDR signaling. Thus, an authentic MYC molecular signature may serve as an important biomarker in characterizing the genomic integrity in hiPSCs.

Human Pluripotent Stem Cells (iPSC) Generation, Culture, and Differentiation to Lung Progenitor Cells.

Induced pluripotent stem (iPS) cells are the product of adult somatic cell reprogramming to an embryonic-like state by inducing a "forced" expression of specific genes. They are similar to natural pluripotent stem cells, such as embryonic stem (ES) cells, in many aspects, such as the expression of certain stem cell genes and potency and differentiability. Human iPS cells are invaluable resource for basic research, cell therapy, drug discovery, and human organ tissue engineering. iPS cells can be derived from the patient to be treated and thus are genetically identical cells that may avoid immune rejection. The following protocols offer a general guideline for the induction of iPSCs from fibroblasts, and for culture and expansion to produce lung precursor cells.

The Application of Human iPSCs in Neurological Diseases: From Bench to Bedside.

In principle, induced pluripotent stem cells (iPSCs) are generated from somatic cells by reprogramming and gaining the capacity to self-renew indefinitely as well as the ability to differentiate into cells of different lineages. Human iPSCs have absolute advantages over human embryonic stem cells (ESCs) and animal models in disease modeling, drug screening, and cell replacement therapy. Since Takahashi and Yamanaka first described in 2007 that iPSCs can be generated from human adult somatic cells by retroviral transduction of the four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc, disease specific iPSC lines have sprung up worldwide like bamboo shoots after a spring rain, making iPSC one of the hottest and fastest moving topics in modern science. The craze for iPSCs has spread throughout main branches of clinical medicine, covering neurology, hematology, cardiology, endocrinology, hepatology, ophthalmology, and so on. Here in this paper, we will focus on the clinical application of human iPSCs in disease modeling, drug screening, and cell replacement therapy for neurological diseases.

A Human Bone Marrow-Derived Stromal Cell Population with Hemogenic Potential

During ontogeny, definitive hematopoietic stem/progenitor cells (HSC) are thought to arise from vascular endothelial cells, through an endothelial-to-hematopoietic transition, a natural process that occurs in unique, specialized embryonic hemogenic endothelial cells. Developmental studies, and experiments using pluripotent stem cells in an effort to recapitulate this process and thereby gain a better understanding of the emergence of definitive hematopoiesis, have collectively led to the prevailing view that the hemogenic endothelium constitutes a transient population of cells within the embryo that rapidly disappears during development and is absent in the adult. Herein, we provide the first evidence that at early time points of gestation, prior to the establishment of hematopoiesis, a unique subpopulation of Stro-1+ cells present within the inner part of the developing human bone marrow co-expresses APLNR, a marker of angiogenic mesoderm. Moreover, these Stro-1+APLNR+ cells express multiple other markers described for hemogenic endothelium, and subsequently contribute to the vasculature, cartilage, and bone. Importantly, we also show that cells expressing these same markers of primitive mesoderm/hemogenic endothelium persist at low frequency within the adult marrow. These adult-derived cells can be extensively expanded in vitro without loss of potential, but lack hematopoietic colony-forming potential in vitro. However, upon transplantation into a fetal microenvironment, clonally-derived populations of these adult Stro1+ isolated stromal progenitors (SIPs) not only contribute to the vasculature and nascent BM niches, but also efficiently generate, at a clonal level, hematopoietic stem cells (HSC) that are capable of robust, multilineage hematopoietic reconstitution, with generation of both myeloid and lymphoid cells upon serial transplantation. In conclusion, our studies have thus uncovered the latent potential of a highly expandable population of seemingly vestigial adult human somatic cells, whose ontogenic history includes a phenotype identical to that described for hemogenic endothelium. We have also shown that, if provided with the appropriate/necessary inductive factors, these unique adult cells are capable of giving rise to hematopoietic cells that fulfill the gold standard criteria for bona fide HSC. Therefore, these cells could potentially be more amenable to reprogramming technologies, to produce HSC that could be used to treat/cure a broad variety of blood diseases. DisclosuresNo relevant conflicts of interest to declare.

Abstract 18845: Induced Cardiac Progenitor Cells Differentiate Into Cardiac Lineage Cells in vivo and Improve Survival in Mice post Myocardial Infarction

Several studies have reported reprogramming of fibroblasts (Fibs) to induced cardiomyocytes, and we have recently reprogrammed mouse Fibs to induced cardiac progenitor cells (iCPCs), which may be more favorable for cardiac repair because of their expandability and multipotency. Adult cardiac (AC), lung and tail-tip Fibs from an Nkx2.5-EYFP reporter mouse were reprogrammed using a combination of five defined factors into iCPCs. Transcriptome and immunocytochemistry analysis revealed that iCPCs were cardiac mesoderm-restricted progenitors that expressed CPC markers including Nkx2.5, Gata4, Irx4, Tbx5, Cxcr4, Flk1 etc. iCPCs could be extensively expanded (over 30 passages) while maintaining multipotency to differentiate in vitro into cardiac lineage cells including cardiomyocytes (CMs), smooth muscle cells and endothelial cells. iCPC derived CMs upon co-culture with mESC-derived CMs formed intercellular gap junctions, exhibited calcium transients, and contractions. The purpose of this study was to determine the in vivo potency of iCPCs. Given that the Nkx2.5-EYFP reporter identifies embryonic CPCs, we first tested the embryonic potency of iCPCs using an ex vivo whole embryo culture model injecting cells into the cardiac crescent (CC) of E8.5 mouse embryos and culturing for 24 to 48 hours. GFP labeled AC Fibs were first tested and live imaging revealed that after 24 hours these cells were rejected from the embryo proper and localized to the ecto-placental cone. In contrast, iCPCs reprogrammed from AC Fibs when injected into the CC localized to the developing heart tube and differentiated into MLC2v, αMHC and cardiac actin expressing CMs. Further we injected iCPCs into infarcted adult mouse hearts and determined their regenerative potential after 1-4 wks. The iCPCs significantly improved survival (p<0.01 Mantel-Cox test) in treated animals (75%) as compared to control (11%). Immunohistochemistry revealed that injected iCPCs localized to the scar area and differentiated into cardiac lineage cells including CMs (cardiac actin). These results indicate that lineage reprogramming of adult somatic cells into iCPCs provides a scalable cell source for cardiac regenerative therapy as well as drug discovery and disease modeling.

SOX2 and SOX2-MYC Reprogramming Process of Fibroblasts to the Neural Stem Cells Compromised by Senescence.

Tumorigenic potential of induced pluripotent stem cells (iPSCs) infiltrating population of induced neural stem cells (iNSCs) generated from iPSCs may limit their medical applications. To overcome such a difficulty, direct reprogramming of adult somatic cells into iNSCs was proposed. The aim of this study was the systematic comparison of induced neural cells (iNc) obtained with different methods—direct reprogramming of human adult fibroblasts with either SOX2 (SiNSc-like) or SOX2 and c-MYC (SMiNSc-like) and induced pluripotent stem cells differentiation to ebiNSc—in terms of gene expression profile, differentiation potential as well as proliferation properties. Immunocytochemistry and real-time PCR analyses were used to evaluate gene expression profile and differentiation potential of various iNc types. Bromodeoxyuridine (BrdU) incorporation and senescence-associated beta-galactosidase (SA-β-gal) assays were used to estimate proliferation potential. All three types of iNc were capable of neuronal differentiation; however, astrocytic differentiation was possible only in case of ebiNSc. Contrary to ebiNSc generation, the direct reprogramming was rarely a propitious process, despite 100% transduction efficiency. The potency of direct iNSCs-like cells generation was lower as compared to iNSCs obtained by iPSCs differentiation, and only slightly improved when c-MYC was added. Directly reprogrammed iNSCs-like cells were lacking the ability to differentiate into astrocytic cells and characterized by poor efficiency of neuronal cells formation. Such features indicated that these cells could not be fully reprogrammed, as confirmed mainly with senescence detection. Importantly, SiNSc-like and SMiNSc-like cells were unable to achieve the long-term survival and became senescent, which limits their possible therapeutic applicability. Our results suggest that iNSCs-like cells, generated in the direct reprogramming attempts, were either not fully reprogrammed or reprogrammed only into neuronal progenitors, mainly because of the inaccuracies of currently available protocols.

Telomerase Reverse Transcriptase and Peroxisome Proliferator-Activated Receptor γ Co-Activator-1α Cooperate to Protect Cells from DNA Damage and Mitochondrial Dysfunction in Vascular Senescence.

Reduced telomere length with increasing age in dividing cells has been implicated in contributing to the pathologies of human aging, which include cardiovascular and metabolic disorders, through induction of cellular senescence. Telomere shortening results from the absence of telomerase, an enzyme required to maintain telomere length. Telomerase reverse transcriptase (TERT), the protein subunit of telomerase, is expressed only transiently in a subset of adult somatic cells, which include stem cells and smooth muscle cells. A recent report from Xiong and colleagues demonstrates a pivotal role for the transcription co-factor peroxisome proliferator-activated receptor γ co-activator-1α (PGC-1α) in maintaining TERT expression and preventing vascular senescence and atherosclerosis in mice. Ablation of PGC-1α reduced TERT expression and increased DNA damage and reactive oxygen species (ROS), resulting in shortened telomeres and vascular senescence. In the ApoE(-/-) mouse model of atherosclerosis, forced expression of PGC-1α increased expression of TERT, extended telomeres, and reversed genomic DNA damage, vascular senescence, and the development of atherosclerotic plaques. Alpha lipoic acid (ALA) stimulated expression of PGC-1α and TERT and reversed DNA damage, vascular senescence, and atherosclerosis, similarly to ectopic expression of PGC-1α. ALA stimulated cyclic adenosine monophosphate (cAMP) signaling, which in turn activated the cAMP response element-binding protein (CREB), a co-factor for PGC-1α expression. The possibility that ALA might induce TERT to extend telomeres in human cells suggests that ALA may be useful in treating atherosclerosis and other aging-related diseases. However, further investigation is needed to identify whether ALA induces TERT in human cells, which cell types are susceptible, and whether such changes have clinical significance.

Reprogramming of adult stem/progenitor cells into iPSCs without reprogramming factors

Abstract Reprogramming of adult somatic cells into induced pluripotent stem cells (iPSCs) has attracted considerable attention in both the scientific and public communities. This is due to the importance of iPSCs in drug screening, disease modeling, cell transplantation therapies and regenerative medicine. A lot of efforts have been devoted to the generation of iPSCs with fewer reprogramming factors and with higher efficiencies. It has been shown that removal of reprogramming barriers increases the efficiency of iPSC generation from differentiated cells up to 90%. Interestingly, having relatively fast cell cycle kinetics, plasticity and endogenous expression of particular pluripotency regulators make adult stem/progenitor cells potentially elite cells poised to become iPSCs. Moreover, it has been demonstrated that adult stem/progenitor cells are more amenable to pluripotent reprogramming than mature cells. Accordingly, it is hypothesized that certain adult stem cells could be reprogrammed into iPSCs without overexpression of exogenous pluripotency transcription factors by only combinatorial modulation of barriers and enhancers and relying on the endogenous expression of key reprogramming factors (e.g. Oct4, Sox2, etc.).

Methods of Liver Stem Cell Therapy in Rodents as Models of Human Liver Regeneration in Hepatic Failure.

Cell therapy is a promising intervention for treating liver diseases and liver failure. Different animal models of human liver cell therapy have been developed in recent years. Rats and mice are the most commonly used liver failure models. In fact, rodent models of hepatic failure have shown significant improvement in liver function after cell infusion. With the advent of stem-cell technologies, it is now possible to re-programme adult somatic cells such as skin or hair-follicle cells from individual patients to stem-like cells and differentiate them into liver cells. Such regenerative stem cells are highly promising in the personalization of cell therapy. The present review article will summarize current approaches to liver stem cell therapy with rodent models. In addition, we discuss common cell tracking techniques and how tracking data help to direct liver cell therapy research in animal models of hepatic failure.

E-Ras improves the efficiency of reprogramming by facilitating cell cycle progression through JNK–Sp1 pathway

We have previously shown that pluripotent stem cells can be induced from adult somatic cells which were exposed to protein extracts isolated from mouse embryonic stem cells (mESC). Interestingly, generation of induced pluripotent stem (iPS) cells depended on the background of ES cell lines; possible by extracts from C57, but not from E14. Proteomic analysis of two different mES cell lines (C57 and E14) shows that embryonic Ras (E-Ras) is expressed differently in two mES cell lines; high level of E-Ras only in C57 mESC whose extracts allows iPS cells production from somatic cells. Here, we show that E-Ras augments the efficiency in reprogramming of fibroblast by promoting cell proliferation. We found that over-expression of E-Ras in fibroblast increased cell proliferation which was caused by specific up-regulation of cyclins D and E, not A or B, leading to the accelerated G1 to S phase transition. To figure out the common transcription factor of cyclins D and E, we used TRANSFAC database and selected SP1 as a candidate which was confirmed as enhancer of cyclins D and E by luciferase promoter assay using mutants. As downstream signaling pathways, E-Ras activated only c-Jun N-terminal kinases (JNK) but not ERK or p38. Inhibition of JNK prevented E-Ras-mediated induction of pSP1, cyclins D, E, and cell proliferation. Finally, E-Ras transduction to fibroblast enhanced the efficiency of iPS cell generation by 4 factors (Oct4/Klf4/Sox2/C-myc), which was prevented by JNK inhibitor. In conclusion, E-Ras stimulates JNK, enhances binding of Sp1 on the promoter of cyclins D and E, leading to cell proliferation. E-Ras/JNK axis is a critical mechanism to generate iPS cells by transduction of 4 factors or by treatment of mESC protein extracts.

Challenges, progress, and new directions in stem cell therapies: a new section launched in Clinical and Translational Medicine.

Challenges, progress, and new directions in stem cell therapies: a new section launched in Clinical and Translational Medicine.

Modeling autosomal dominant optic atrophy using induced pluripotent stem cells and identifying potential therapeutic targets

Many retinal degenerative diseases are caused by the loss of retinal ganglion cells (RGCs). Autosomal dominant optic atrophy is the most common hereditary optic atrophy disease and is characterized by central vision loss and degeneration of RGCs. Currently, there is no effective treatment for this group of diseases. However, stem cell therapy holds great potential for replacing lost RGCs of patients. Compared with embryonic stem cells, induced pluripotent stem cells (iPSCs) can be derived from adult somatic cells, and they are associated with fewer ethical concerns and are less prone to immune rejection. In addition, patient-derived iPSCs may provide us with a cellular model for studying the pathogenesis and potential therapeutic agents for optic atrophy. In this study, iPSCs were obtained from patients carrying an OPA1 mutation (OPA1 +/− -iPSC) that were diagnosed with optic atrophy. These iPSCs were differentiated into putative RGCs, which were subsequently characterized by using RGC-specific expression markers BRN3a and ISLET-1. Mutant OPA1 +/− -iPSCs exhibited significantly more apoptosis and were unable to efficiently differentiate into RGCs. However, with the addition of neural induction medium, Noggin, or estrogen, OPA1 +/− -iPSC differentiation into RGCs was promoted. Our results suggest that apoptosis mediated by OPA1 mutations plays an important role in the pathogenesis of optic atrophy, and both noggin and β-estrogen may represent potential therapeutic agents for OPA1-related optic atrophy.

Limiting replication stress during somatic cell reprogramming reduces genomic instability in induced pluripotent stem cells

The generation of induced pluripotent stem cells (iPSC) from adult somatic cells is one of the most remarkable discoveries in recent decades. However, several works have reported evidence of genomic instability in iPSC, raising concerns on their biomedical use. The reasons behind the genomic instability observed in iPSC remain mostly unknown. Here we show that, similar to the phenomenon of oncogene-induced replication stress, the expression of reprogramming factors induces replication stress. Increasing the levels of the checkpoint kinase 1 (CHK1) reduces reprogramming-induced replication stress and increases the efficiency of iPSC generation. Similarly, nucleoside supplementation during reprogramming reduces the load of DNA damage and genomic rearrangements on iPSC. Our data reveal that lowering replication stress during reprogramming, genetically or chemically, provides a simple strategy to reduce genomic instability on mouse and human iPSC.

Inducible Lentivirus-Mediated Expression of the Oct4 Gene Affects Multilineage Differentiation of Adult Human Bone Marrow-Derived Mesenchymal Stem Cells.

The octamer-binding transcription factor 4 (Oct4) gene plays an important role in maintaining the undifferentiated state of embryonic stem cells (ESCs) and reprogramming adult somatic cells into induced pluripotent stem cells (iPSCs). In the present study, we transduced human bone marrow-derived mesenchymal stem cells (hMSCs) using tetracycline-on (Tet-On) lentiviruses carrying human Oct4 to examine the effects of regulated expression of human Oct4 on the proliferation and differentiation of hMSCs. hMSCs were efficiently transduced by Tet-On lentiviruses to express regulated levels of human Oct4 with doxycycline (Dox), as examined by immunofluorescent staining, flow cytometry, and quantitative real time-PCR (qRT-PCR) assays. Ectopic expression of Oct4 in transduced hMSCs increased the ability of colony formation. Continued expression of Oct4 further enhanced adipogenic differentiation of hMSCs, and transient expression of Oct4 sufficiently enhanced osteogenic differentiation of hMSCs. qRT-PCR analysis showed that ectopic expression of Oct4 in transduced hMSCs temporally increased the expression of Sox2 and c-Myc. Interestingly, ectopic expression of Oct4 reduced neuronal differentiation of hMSCs when incubated under neuronal differentiation conditions. Our results suggest that ectopic expression of human Oct4 leads to temporal changes in multilineage differentiation of hMSCs and may inhibit neuronal differentiation of hMSCs.

Teaching and learning in a Xenopus research lab.

You have been working with animal models since your PhD research at Fudan University in Shanghai. What inspired you to pursue a career in research with lab animals? I was a sophomore at Shandong University when ‘Dolly’ the sheep was cloned by nuclear transfer from an adult somatic cell. I was inspired by this news and began studying literature on fertilization and development, where I found the seminal work of pioneering experimental biologist Dr. Tschou Su. Dr. Tschou’s research was fascinating to me because it demonstrated that unfertilized toad oocytes could be punctured by a needle and still develop into normal adults. I later accepted an offer to pursue my PhD at Fudan University under Professor Jiake Tso, who inherited the lab and research of Dr. Tschou, where I began studying oocyte maturation in toads. You currently research genomic instability and teach biology as an assistant professor at UNC Charlotte. How have you developed and balanced your research interests with your teaching responsibilities? My process of becoming an independent scholar benefitted from the guidance of strong mentors, who taught me how to be independent and find my own path. This approach does not eschew collaboration with other scientists but rather encourages critical thinking within my own research. My career goal now is to be a successful teacher and scholar. I have trained in classroom instruction at Harvard University and I attended several workshops and seminars for teaching in the greater Boston area. I was fortunate to work as a teaching assistant at Harvard, which better prepared me to teach biology. Here, at UNC Charlotte, the Center for Teaching and Learning offers teaching workshops and learning resources, and the National Science Foundation–funded ADVANCE program provides resources for mentoring and new faculty transitions. Finally, my colleagues here have helped me refine my research and teaching, through comments on grant proposals, classroom observations and peer evaluation. Your current research program at UNC Charlotte involves postdoctoral fellows and graduate, undergraduate and high school students. What kinds of learning opportunities does your research offer? As a faculty member of UNC Charlotte, I am committed to mentoring students and fellows at many different levels. Students in my lab are often supported by various scholar programs, and graduate students have opportunities to teach lab sessions as teaching assistants and to deliver presentations at conferences. I hold a monthly discussion series in my lab that covers topics of career development, such as “How to be a Professional Scientist”, “Grant Proposal Writing 101” and “Presentation Skills.” I have also implemented a ‘peer learning’ model in my lab, wherein postdoctoral fellows advise graduate students, who, in turn, supervise undergraduate students. In this way students and fellows practice teaching and learning outside the classroom. I usually hold weekly group meetings to assess and discuss peer learning, progress on lab projects and any problems that we encounter. As a testament to my lab’s integration of teaching and research, I am proud to share that an undergraduate honors student shared first authorship with a graduate student on a recent manuscript published in Proceedings of the National Academy of Sciences. You helped establish a new Xenopus facility within the UNC Charlotte vivarium. Tell us about its challenges and rewards. Our new facility houses approximately 200 frogs on three stand-alone rack systems within the vivarium, and it is a challenge to keep the frogs healthy. Luckily we have excellent support at the vivarium, including staff technicians and the director, our attending veterinarian. After my Xenopus protocol was approved, I became a standing member of the IACUC and I now participate in many of its functions, including protocol review and facility monitoring. Our Xenopus facility has generally created opportunities to share our research with the broader scientific community. My students have produced a resource for the Journal of Visualized Experiments, describing in video and in writing how we use Xenopus egg extracts to study pathways of DNA damage response. We also share our research through tours of the lab as part of the North Carolina Science Festival.

Human Induced Pluripotent Stem Cell-Derived Microvesicles Transmit RNAs and Proteins to Recipient Mature Heart Cells Modulating Cell Fate and Behavior.

Microvesicles (MVs) are membrane-enclosed cytoplasmic fragments released by normal and activated cells that have been described as important mediators of cell-to-cell communication. Although the ability of human induced pluripotent stem cells (hiPSCs) to participate in tissue repair is being increasingly recognized, the use of hiPSC-derived MVs (hiPSC-MVs) in this regard remains unknown. Accordingly, we investigated the ability of hiPSC-MVs to transfer bioactive molecules including mRNA, microRNA (miRNA), and proteins to mature target cells such as cardiac mesenchymal stromal cells (cMSCs), and we next analyzed effects of hiPSC-MVs on fate and behavior of such target cells. The results show that hiPSC-MVs derived from integration-free hiPSCs cultured under serum-free and feeder-free conditions are rich in mRNA, miRNA, and proteins originated from parent cells; however, the levels of expression vary between donor cells and MVs. Importantly, we found that transfer of hiPSC components by hiPSC-MVs impacted on transcriptome and proteomic profiles of target cells as well as exerted proliferative and protective effects on cMSCs, and enhanced their cardiac and endothelial differentiation potential. hiPSC-MVs also transferred exogenous transcripts from genetically modified hiPSCs that opens new perspectives for future strategies to enhance MV content. We conclude that hiPSC-MVs are effective vehicles for transferring iPSC attributes to adult somatic cells, and hiPSC-MV-mediated horizontal transfer of RNAs and proteins to injured tissues may be used for therapeutic tissue repair. In this study, for the first time, we propose a new concept of use of hiPSCs as a source of safe acellular bioactive derivatives for tissue regeneration.