1 1359 105 DEVELOPMENT REFRACTORINESS OF MLL-REARRANGED HUMAN B CELL ACUTE LEUKEMIAS TO REPROGRAMMING INTO PLURIPOTENCY. INDUCED PLURIPOTENT STEM CELLS (IPSCS) ARE A POWERFUL TOOL FOR DISEASE MODELING. THEY ARE ROUTINELY GENERATED FROM HEALTHY DONORS AND PATIENTS FROM MULTIPLE CELL TYPES AT DIFFERENT DEVELOPMENTAL STAGES. HOWEVER, REPROGRAMMING LEUKEMIAS IS AN EXTREMELY INEFFICIENT PROCESS. FEW STUDIES GENERATED IPSCS FROM PRIMARY CHRONIC MYELOID LEUKEMIAS, BUT IPSC GENERATION FROM ACUTE MYELOID OR LYMPHOID LEUKEMIAS (ALL) HAS NOT BEEN ACHIEVED. WE ATTEMPTED TO GENERATE IPSCS FROM DIFFERENT SUBTYPES OF B-ALL TO ADDRESS THE DEVELOPMENTAL IMPACT OF LEUKEMIC FUSION GENES. OKSM(L)-EXPRESSING MONO/POLYCISTRONIC-, RETROVIRAL/LENTIVIRAL/EPISOMAL-, AND SENDAI VIRUS VECTOR-BASED REPROGRAMMING STRATEGIES FAILED TO RENDER IPSCS IN VITRO AND IN VIVO. ADDITION OF TRANSCRIPTOMIC-EPIGENETIC REPROGRAMMING "BOOSTERS" ALSO FAILED TO GENERATE IPSCS FROM B CELL BLASTS AND B-ALL LINES, AND WHEN IPSCS EMERGED THEY LACKED LEUKEMIC FUSION GENES, DEMONSTRATING NON-LEUKEMIC MYELOID ORIGIN. CONVERSELY, MLL-AF4-OVEREXPRESSING HEMATOPOIETIC STEM CELLS/B PROGENITORS WERE SUCCESSFULLY REPROGRAMMED, INDICATING THAT B CELL ORIGIN AND LEUKEMIC FUSION GENE WERE NOT REPROGRAMMING BARRIERS. GLOBAL TRANSCRIPTOME/DNA METHYLOME PROFILING SUGGESTED A DEVELOPMENTAL/DIFFERENTIATION REFRACTORINESS OF MLL-REARRANGED B-ALL TO REPROGRAMMING INTO PLURIPOTENCY. 2016 2 3839 31 IPSC-DERIVED NEURAL PRECURSOR CELLS: POTENTIAL FOR CELL TRANSPLANTATION THERAPY IN SPINAL CORD INJURY. A NUMBER OF STUDIES HAVE DEMONSTRATED THAT TRANSPLANTATION OF NEURAL PRECURSOR CELLS (NPCS) PROMOTES FUNCTIONAL RECOVERY AFTER SPINAL CORD INJURY (SCI). HOWEVER, THE NPCS HAD BEEN MOSTLY HARVESTED FROM EMBRYONIC STEM CELLS OR FETAL TISSUE, RAISING THE ETHICAL CONCERN. YAMANAKA AND HIS COLLEAGUES ESTABLISHED INDUCED PLURIPOTENT STEM CELLS (IPSCS) WHICH COULD BE GENERATED FROM SOMATIC CELLS, AND THIS INNOVATIVE DEVELOPMENT HAS MADE RAPID PROGRESSION IN THE FIELD OF SCI REGENERATION. WE AND OTHER GROUPS SUCCEEDED IN PRODUCING NPCS FROM IPSCS, AND DEMONSTRATED BENEFICIAL EFFECTS AFTER TRANSPLANTATION FOR ANIMAL MODELS OF SCI. IN PARTICULAR, EFFICACY OF HUMAN IPSC-NPCS IN NON-HUMAN PRIMATE SCI MODELS FOSTERED MOMENTUM OF CLINICAL APPLICATION FOR SCI PATIENTS. AT THE SAME TIME, HOWEVER, ARTIFICIAL INDUCTION METHODS IN IPSC TECHNOLOGY CREATED ALTERNATIVE ISSUES INCLUDING GENETIC AND EPIGENETIC ABNORMALITIES, AND TUMORIGENICITY AFTER TRANSPLANTATION. TO OVERCOME THESE PROBLEMS, IT IS CRITICALLY IMPORTANT TO SELECT ORIGINS OF SOMATIC CELLS, USE INTEGRATION-FREE SYSTEM DURING TRANSFECTION OF REPROGRAMMING FACTORS, AND THOROUGHLY INVESTIGATE THE CHARACTERISTICS OF IPSC-NPCS WITH RESPECT TO QUALITY MANAGEMENT. MOREOVER, SINCE MOST OF THE PREVIOUS STUDIES HAVE FOCUSED ON SUBACUTE PHASE OF SCI, ESTABLISHMENT OF EFFECTIVE NPC TRANSPLANTATION SHOULD BE EVALUATED FOR CHRONIC PHASE HEREAFTER. OUR GROUP IS CURRENTLY PREPARING CLINICAL-GRADE HUMAN IPSC-NPCS, AND WILL MOVE FORWARD TOWARD CLINICAL STUDY FOR SUBACUTE SCI PATIENTS SOON IN THE NEAR FUTURE. 2018 3 2697 30 EX VIVO MODELS OF CHRONIC GRANULOMATOUS DISEASE. INDUCED PLURIPOTENT STEM CELLS (IPSCS) ARE PLURIPOTENT STEM CELLS THAT CAN BE ESTABLISHED FROM DEDIFFERENTIATION OF ALL SOMATIC CELL TYPES BY EPIGENETIC PHENOMENA. IPSCS CAN BE DIFFERENTIATED INTO ANY MATURE CELLS LIKE NEURONS, HEPATOCYTES, OR PANCREATIC CELLS THAT HAVE NOT BEEN EASILY AVAILABLE TO DATE. THUS, IPSCS ARE WIDELY USED FOR DISEASE MODELING, DRUG DISCOVERY, AND CELL THERAPY DEVELOPMENT. HERE, WE DESCRIBE A PROTOCOL TO OBTAIN HUMAN MATURE AND FUNCTIONAL NEUTROPHILS AND MACROPHAGES AS EX VIVO MODELS OF X-LINKED CHRONIC GRANULOMATOUS DISEASE (X-CGD). THIS METHOD CAN BE APPLIED TO MODEL THE OTHER GENETIC FORMS OF CGD. WE ALSO DESCRIBE METHODS FOR TESTING THE CHARACTERISTICS AND FUNCTIONS OF NEUTROPHILS AND MACROPHAGES BY MORPHOLOGY, PHAGOCYTOSIS ASSAY, RELEASE OF GRANULE MARKERS OR CYTOKINES, CELL SURFACE MARKERS, AND NADPH OXIDASE ACTIVITY. 2019 4 2928 34 GENERATION OF IPSCS FROM CULTURED HUMAN MALIGNANT CELLS. INDUCED PLURIPOTENT STEM CELLS (IPSCS) CAN BE GENERATED FROM VARIOUS DIFFERENTIATED CELL TYPES BY THE EXPRESSION OF A SET OF DEFINED TRANSCRIPTION FACTORS. SO FAR, IPSCS HAVE BEEN GENERATED FROM PRIMARY CELLS, BUT IT IS UNCLEAR WHETHER HUMAN CANCER CELL LINES CAN BE REPROGRAMMED. HERE WE DESCRIBE THE GENERATION AND CHARACTERIZATION OF IPSCS DERIVED FROM HUMAN CHRONIC MYELOID LEUKEMIA CELLS. WE SHOW THAT, DESPITE THE PRESENCE OF ONCOGENIC MUTATIONS, THESE CELLS ACQUIRED PLURIPOTENCY BY THE EXPRESSION OF 4 TRANSCRIPTION FACTORS AND UNDERWENT DIFFERENTIATION INTO CELL TYPES DERIVED OF ALL 3 GERM LAYERS DURING TERATOMA FORMATION. INTERESTINGLY, ALTHOUGH THE PARENTAL CELL LINE WAS STRICTLY DEPENDENT ON CONTINUOUS SIGNALING OF THE BCR-ABL ONCOGENE, ALSO TERMED ONCOGENE ADDICTION, REPROGRAMMED CELLS LOST THIS DEPENDENCY AND BECAME RESISTANT TO THE BCR-ABL INHIBITOR IMATINIB. THIS FINDING INDICATES THAT THE THERAPEUTIC AGENT IMATINIB TARGETS CELLS IN A SPECIFIC EPIGENETIC DIFFERENTIATED CELL STATE, AND THIS MAY CONTRIBUTE TO ITS INABILITY TO FULLY ERADICATE DISEASE IN CHRONIC MYELOID LEUKEMIA PATIENTS. 2010 5 454 36 APPLICATIONS OF INDUCED PLURIPOTENT STEM CELL TECHNOLOGIES IN SPINAL CORD INJURY. NUMEROUS BASIC RESEARCH STUDIES HAVE SUGGESTED THE POTENTIAL EFFICACY OF NEURAL PRECURSOR CELL (NPC) TRANSPLANTATION IN SPINAL CORD INJURY (SCI). HOWEVER, IN MOST SUCH STUDIES, THE ORIGIN OF THE CELLS USED WAS MAINLY FETAL TISSUE OR EMBRYONIC STEM CELLS, BOTH OF WHICH CARRY POTENTIAL ETHICAL CONCERNS WITH RESPECT TO CLINICAL USE. THE DEVELOPMENT OF INDUCED PLURIPOTENT STEM CELLS (IPSCS) OPENED A NEW PATH TOWARD REGENERATIVE MEDICINE FOR SCI. IPSCS CAN BE GENERATED FROM SOMATIC CELLS BY INDUCTION OF TRANSCRIPTION FACTORS, AND INDUCED TO DIFFERENTIATE INTO NPCS WITH CHARACTERISTICS OF CELLS OF THE CENTRAL NERVOUS SYSTEM. THE BENEFICIAL EFFECT OF IPSC-DERIVED NPC TRANSPLANTATION HAS BEEN REPORTED FROM OUR GROUP AND OTHERS WORKING IN RODENT AND NON-HUMAN PRIMATE MODELS. THESE PROMISING RESULTS FACILITATE THE APPLICATION OF IPSCS FOR CLINICAL APPLICATIONS IN SCI PATIENTS. HOWEVER, IPSCS ALSO HAVE ISSUES, SUCH AS GENETIC/EPIGENETIC ABNORMALITIES AND TUMORIGENESIS BECAUSE OF THE ARTIFICIAL INDUCTION METHOD, THAT MUST BE ADDRESSED PRIOR TO CLINICAL USE. THE SELECTION OF SOMATIC CELLS, GENERATION OF INTEGRATION-FREE IPSCS, AND CHARACTERIZATION OF DIFFERENTIATED NPCS WITH THOROUGH QUALITY MANAGEMENT ARE ALL NEEDED TO ADDRESS THESE POTENTIAL RISKS. TO ENHANCE THE EFFICACY OF THE TRANSPLANTED IPSC-NPCS, ESPECIALLY AT CHRONIC PHASE OF SCI, ADMINISTRATION OF A CHONDROITINASE OR SEMAPHORIN3A INHIBITOR REPRESENTS A POTENTIALLY IMPORTANT MEANS OF PROMOTING AXONAL REGENERATION THROUGH THE LESION SITE. THE COMBINED USE OF REHABILITATION WITH SUCH CELL THERAPY APPROACHES IS ALSO IMPORTANT, AS REPETITIVE TRAINING ENHANCES NEURITE OUTGROWTH OF TRANSPLANTED CELLS AND STRENGTHENS NEURAL CIRCUITS AT CENTRAL PATTERN GENERATORS. OUR GROUP HAS ALREADY EVALUATED CLINICAL GRADE IPSC-DERIVED NPCS, AND WE LOOK FORWARD TO INITIATING CLINICAL TESTING AS THE NEXT STEP TOWARD DETERMINING WHETHER THIS APPROACH IS SAFE AND EFFECTIVE FOR CLINICAL USE. THIS ARTICLE IS PART OF THE MINI REVIEW SERIES "60TH ANNIVERSARY OF THE JAPANESE SOCIETY FOR NEUROCHEMISTRY". 2017 6 2444 29 EPIGENETIC STATES OF NEPHRON PROGENITORS AND EPITHELIAL DIFFERENTIATION. IN MAMMALS, FORMATION OF NEW NEPHRONS ENDS PERINATALLY DUE TO CONSUMPTION OF MESENCHYMAL PROGENITOR CELLS. PREMATURE DEPLETION OF PROGENITORS DUE TO PREMATURITY OR POSTNATAL LOSS OF NEPHRONS DUE TO INJURY CAUSES CHRONIC KIDNEY DISEASE AND HYPERTENSION. INTENSIVE EFFORTS ARE CURRENTLY INVESTED IN DESIGNING REGENERATIVE STRATEGIES TO FORM NEW NEPHRON PROGENITORS FROM PLURIPOTENT CELLS, WHICH UPON FURTHER DIFFERENTIATION PROVIDE A POTENTIAL SOURCE OF NEW NEPHRONS. TO KNOW IF REPROGRAMED RENAL CELLS CAN MAINTAIN THEIR IDENTITY AND FATE REQUIRES KNOWLEDGE OF THE EPIGENETIC STATES OF NATIVE NEPHRON PROGENITORS AND THEIR PROGENY. IN THIS ARTICLE, WE SUMMARIZE CURRENT KNOWLEDGE AND GAPS IN THE EPIGENOMIC LANDSCAPE OF THE DEVELOPING KIDNEY. WE NOW KNOW THAT PAX2/PTIP/H3K4 METHYLTRANSFERASE ACTIVITY PROVIDES THE INITIAL EPIGENETIC SPECIFICATION SIGNAL TO THE METANEPHRIC MESENCHYME. DURING NEPHROGENESIS, THE CAP MESENCHYME HOUSING NEPHRON PROGENITORS IS ENRICHED IN BIVALENT CHROMATIN MARKS; AS TUBULOGENESIS PROCEEDS, THE TUBULAR EPITHELIUM ACQUIRES H3K79ME2. THE LATTER MARK IS UNIQUELY INDUCED DURING EPITHELIAL DIFFERENTIATION. ANALYSIS OF HISTONE LANDSCAPES IN CLONAL METANEPHRIC MESENCHYME CELL LINES AND IN WILMS TUMOR AND NORMAL FETAL KIDNEY HAS REVEALED THAT PROMOTERS OF POISED NEPHROGENESIS GENES CARRY BIVALENT HISTONE SIGNATURES IN PROGENITORS. DIFFERENTIATION OR STIMULATION OF WNT SIGNALING PROMOTES RESOLUTION OF BIVALENCY; THIS DOES NOT OCCUR IN WILMS TUMOR CELLS CONSISTENT WITH THEIR DEVELOPMENTAL ARREST. THE USE OF SMALL CELL NUMBER CHIP-SEQ SHOULD FACILITATE THE CHARACTERIZATION OF THE CHROMATIN LANDSCAPE OF THE METANEPHRIC MESENCHYME AND VARIOUS NEPHRON COMPARTMENTS DURING NEPHROGENESIS. ONLY THEN WE WILL KNOW IF STEM AND SOMATIC CELL REPROGRAMMING INTO KIDNEY PROGENITORS RECAPITULATES NORMAL DEVELOPMENT. 2015 7 6284 32 THE POTENTIAL OF HUMAN INDUCED PLURIPOTENT STEM CELLS FOR MODELLING DIABETIC WOUND HEALING IN VITRO. IMPAIRED WOUND HEALING AND ULCERATION CAUSED BY DIABETES MELLITUS, IS A SIGNIFICANT HEALTHCARE BURDEN, MARKEDLY IMPAIRS QUALITY OF LIFE FOR PATIENTS, AND IS THE MAJOR CAUSE OF AMPUTATION WORLDWIDE. CURRENT EXPERIMENTAL APPROACHES USED TO INVESTIGATE THE COMPLEX WOUND HEALING PROCESS OFTEN INVOLVE CULTURES OF FIBROBLASTS AND/OR KERATINOCYTES IN VITRO, WHICH CAN BE LIMITED IN TERMS OF COMPLEXITY AND CAPACITY, OR UTILISATION OF RODENT MODELS IN WHICH THE MECHANISMS OF WOUND REPAIR DIFFER SUBSTANTIVELY FROM THAT IN HUMANS. HOWEVER, ADVANCES IN TISSUE ENGINEERING, AND THE DISCOVERY OF STRATEGIES TO REPROGRAMME ADULT SOMATIC CELLS TO PLURIPOTENCY, HAS LED TO THE POSSIBILITY OF DEVELOPING MODELS OF HUMAN SKIN ON A LARGE SCALE. GENERATION OF INDUCED PLURIPOTENT STEM CELLS (IPSCS) FROM TISSUES DONATED BY DIABETIC PATIENTS ALLOWS THE (EPI)GENETIC BACKGROUND OF THIS DISEASE TO BE STUDIED, AND THE ABILITY TO DIFFERENTIATE IPSCS TO MULTIPLE CELL TYPES FOUND WITHIN SKIN MAY FACILITATE THE DEVELOPMENT OF MORE COMPLEX SKIN MODELS; THESE ADVANCES OFFER KEY OPPORTUNITIES FOR IMPROVING MODELLING OF WOUND HEALING IN DIABETES, AND THE DEVELOPMENT OF EFFECTIVE THERAPEUTICS FOR TREATMENT OF CHRONIC WOUNDS. 2018 8 5870 36 SUSTAINED KNOCKDOWN OF A DISEASE-CAUSING GENE IN PATIENT-SPECIFIC INDUCED PLURIPOTENT STEM CELLS USING LENTIVIRAL VECTOR-BASED GENE THERAPY. PATIENT-SPECIFIC INDUCED PLURIPOTENT STEM CELLS (IPSCS) HOLD GREAT PROMISE FOR STUDIES ON DISEASE-RELATED DEVELOPMENTAL PROCESSES AND MAY SERVE AS AN AUTOLOGOUS CELL SOURCE FOR FUTURE TREATMENT OF MANY HEREDITARY DISEASES. NEW GENETIC ENGINEERING TOOLS SUCH AS ZINC FINGER NUCLEASES AND TRANSCRIPTION ACTIVATOR-LIKE EFFECTOR NUCLEASE ALLOW TARGETED CORRECTION OF MONOGENETIC DISORDERS BUT ARE VERY CUMBERSOME TO ESTABLISH. AIMING AT STUDIES ON THE KNOCKDOWN OF A DISEASE-CAUSING GENE, LENTIVIRAL VECTOR-MEDIATED EXPRESSION OF SHORT HAIRPIN RNAS (SHRNAS) IS A VALUABLE OPTION, BUT IT IS LIMITED BY SILENCING OF THE KNOCKDOWN CONSTRUCT UPON EPIGENETIC REMODELING DURING DIFFERENTIATION. HERE, WE PROPOSE AN APPROACH FOR THE EXPRESSION OF A THERAPEUTIC SHRNA IN DISEASE-SPECIFIC IPSCS USING THIRD-GENERATION LENTIVIRAL VECTORS. TARGETING SEVERE ALPHA-1-ANTITRYPSIN (A1AT) DEFICIENCY, WE OVEREXPRESSED A HUMAN MICRORNA 30 (MIR30)-STYLED SHRNA DIRECTED AGAINST THE PIZ VARIANT OF A1AT, WHICH IS KNOWN TO CAUSE CHRONIC LIVER DAMAGE IN AFFECTED PATIENTS. THIS KNOCKDOWN CASSETTE IS TRACEABLE FROM CLONAL IPSC LINES TO DIFFERENTIATED HEPATIC PROGENY VIA AN ENHANCED GREEN FLUORESCENCE PROTEIN REPORTER EXPRESSED FROM THE SAME RNA-POLYMERASE II PROMOTER. IMPORTANTLY, THE CYTOMEGALOVIRUS I/E ENHANCER CHICKEN BETA ACTIN (CAG) PROMOTER-DRIVEN EXPRESSION OF THIS CONSTRUCT IS SUSTAINED WITHOUT TRANSGENE SILENCING DURING HEPATIC DIFFERENTIATION IN VITRO AND IN VIVO. AT LOW LENTIVIRAL COPY NUMBERS PER GENOME WE CONFIRMED A FUNCTIONAL RELEVANT REDUCTION (-66%) OF INTRACELLULAR PIZ PROTEIN IN HEPATIC CELLS AFTER DIFFERENTIATION OF PATIENT-SPECIFIC IPSCS. IN CONCLUSION, WE HAVE DEMONSTRATED THAT LENTIVIRAL VECTOR-MEDIATED EXPRESSION OF SHRNAS CAN BE EFFICIENTLY USED TO KNOCK DOWN AND FUNCTIONALLY EVALUATE DISEASE-RELATED GENES IN PATIENT-SPECIFIC IPSCS. 2013 9 5453 26 REPROGRAMMING OF COPD LUNG FIBROBLASTS THROUGH FORMATION OF INDUCED PLURIPOTENT STEM CELLS. REPROGRAMMING SOMATIC CELLS TO INDUCED PLURIPOTENT STEM CELLS (IPSCS) ELIMINATES MANY EPIGENETIC MODIFICATIONS THAT CHARACTERIZE DIFFERENTIATED CELLS. IN THIS STUDY, WE TESTED WHETHER FUNCTIONAL DIFFERENCES BETWEEN CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) AND NON-COPD FIBROBLASTS COULD BE REDUCED UTILIZING THIS APPROACH. PRIMARY FIBROBLASTS FROM NON-COPD AND COPD PATIENTS WERE REPROGRAMMED TO IPSCS. REPROGRAMMED IPSCS WERE POSITIVE FOR OCT3/4, NANOG, AND SOX2, FORMED EMBRYOID BODIES IN VITRO, AND INDUCED TERATOMAS IN NONOBESE DIABETIC/SEVERE COMBINED IMMUNODEFICIENT MICE. REPROGRAMMED IPSCS WERE THEN DIFFERENTIATED INTO FIBROBLASTS (NON-COPD-I AND COPD-I) AND WERE ASSESSED EITHER FUNCTIONALLY BY CHEMOTAXIS AND GEL CONTRACTION OR FOR GENE EXPRESSION BY MICROARRAYS AND COMPARED WITH THEIR CORRESPONDING PRIMARY FIBROBLASTS. PRIMARY COPD FIBROBLASTS CONTRACTED THREE-DIMENSIONAL COLLAGEN GELS AND MIGRATED TOWARD FIBRONECTIN LESS ROBUSTLY THAN NON-COPD FIBROBLASTS. IN CONTRAST, REDIFFERENTIATED FIBROBLASTS FROM IPSCS DERIVED FROM THE NON-COPD AND COPD FIBROBLASTS WERE SIMILAR IN RESPONSE IN BOTH FUNCTIONAL ASSAYS. MICROARRAY ANALYSIS IDENTIFIED 1,881 GENES THAT WERE DIFFERENTIALLY EXPRESSED BETWEEN PRIMARY COPD AND NON-COPD FIBROBLASTS, WITH 605 GENES DIFFERING BY MORE THAN TWOFOLD. AFTER REDIFFERENTIATION, 112 GENES WERE DIFFERENTIALLY EXPRESSED BETWEEN COPD-I AND NON-COPD-I WITH ONLY THREE GENES BY MORE THAN TWOFOLD. SIMILAR FINDINGS WERE OBSERVED WITH MICRORNA (MIRNA) EXPRESSION: 56 MIRNAS WERE DIFFERENTIALLY EXPRESSED BETWEEN NON-COPD AND COPD PRIMARY CELLS; AFTER REDIFFERENTIATION, ONLY 3 MIRNAS WERE DIFFERENTIALLY EXPRESSED BETWEEN NON-COPD-I AND COPD-I FIBROBLASTS. INTERESTINGLY, OF THE 605 GENES THAT WERE DIFFERENTIALLY EXPRESSED BETWEEN COPD AND NON-COPD FIBROBLASTS, 293 GENES WERE CHANGED TOWARD CONTROL AFTER REDIFFERENTIATION. IN CONCLUSION, FUNCTIONAL AND EPIGENETIC ALTERATIONS OF COPD FIBROBLASTS CAN BE REPROGRAMMED THROUGH FORMATION OF IPSCS. 2014 10 3380 33 HIV-1 INFECTION OF GENETICALLY ENGINEERED IPSC-DERIVED CENTRAL NERVOUS SYSTEM-ENGRAFTED MICROGLIA IN A HUMANIZED MOUSE MODEL. THE CENTRAL NERVOUS SYSTEM (CNS) IS A MAJOR HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 RESERVOIR. MICROGLIA ARE THE PRIMARY TARGET CELL OF HIV-1 INFECTION IN THE CNS. CURRENT MODELS HAVE NOT ALLOWED THE PRECISE MOLECULAR PATHWAYS OF ACUTE AND CHRONIC CNS MICROGLIAL INFECTION TO BE TESTED WITH IN VIVO GENETIC METHODS. HERE, WE DESCRIBE A NOVEL HUMANIZED MOUSE MODEL UTILIZING HUMAN-INDUCED PLURIPOTENT STEM CELL-DERIVED MICROGLIA TO XENOGRAFT INTO MURINE HOSTS. THESE MICE ARE ADDITIONALLY ENGRAFTED WITH HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS THAT SERVED AS A MEDIUM TO ESTABLISH A PERIPHERAL INFECTION THAT THEN SPREAD TO THE CNS MICROGLIA XENOGRAFT, MODELING A TRANS-BLOOD-BRAIN BARRIER ROUTE OF ACUTE CNS HIV-1 INFECTION WITH HUMAN TARGET CELLS. THE APPROACH IS COMPATIBLE WITH IPSC GENETIC ENGINEERING, INCLUDING INSERTING TARGETED TRANSGENIC REPORTER CASSETTES TO TRACK THE XENOGRAFTED HUMAN CELLS, ENABLING THE TESTING OF NOVEL TREATMENT AND VIRAL TRACKING STRATEGIES IN A COMPARATIVELY SIMPLE AND COST-EFFECTIVE WAY VIVO MODEL FOR NEUROHIV. IMPORTANCE: OUR MOUSE MODEL IS A POWERFUL TOOL FOR INVESTIGATING THE GENETIC MECHANISMS GOVERNING CNS HIV-1 INFECTION AND LATENCY IN THE CNS AT A SINGLE-CELL LEVEL. A MAJOR ADVANTAGE OF OUR MODEL IS THAT IT USES IPSC-DERIVED MICROGLIA, WHICH ENABLES HUMAN GENETICS, INCLUDING GENE FUNCTION AND THERAPEUTIC GENE MANIPULATION, TO BE EXPLORED IN VIVO , WHICH IS MORE CHALLENGING TO STUDY WITH CURRENT HEMATOPOIETIC STEM CELL-BASED MODELS FOR NEUROHIV. OUR TRANSGENIC TRACING OF XENOGRAFTED HUMAN CELLS WILL PROVIDE A QUANTITATIVE MEDIUM TO DEVELOP NEW MOLECULAR AND EPIGENETIC STRATEGIES FOR REDUCING THE HIV-1 LATENT RESERVOIR AND TO TEST THE IMPACT OF THERAPEUTIC INFLAMMATION-TARGETING DRUG INTERVENTIONS ON CNS HIV-1 LATENCY. 2023 11 5440 30 RENAL DIFFERENTIATION OF AMNIOTIC FLUID STEM CELLS: PERSPECTIVES FOR CLINICAL APPLICATION AND FOR STUDIES ON SPECIFIC HUMAN GENETIC DISEASES. BACKGROUND: OWING TO GROWING RATES OF DIABETES, HYPERTENSION AND THE AGEING POPULATION, THE PREVALENCE OF END-STAGE RENAL DISEASE, DEVELOPED FROM EARLIER STAGES OF CHRONIC KIDNEY DISEASE, AND OF ACUTE RENAL FAILURE IS DRAMATICALLY INCREASING. DIALYSIS AND PREFERABLE RENAL TRANSPLANTATION ARE WIDELY APPLIED THERAPIES FOR THIS INCURABLE CONDITION. HOWEVER THESE OPTIONS ARE LIMITED BECAUSE OF MORBIDITY, SHORTAGE OF COMPATIBLE ORGANS AND COSTS. THEREFORE, STEM CELL-BASED APPROACHES ARE BECOMING INCREASINGLY ACCEPTED AS AN ALTERNATIVE THERAPEUTIC STRATEGY. DESIGN: THIS REVIEW SUMMARIZES THE CURRENT FINDINGS ON THE NEPHROGENIC POTENTIAL OF AMNIOTIC FLUID STEM (AFS) CELLS AND THEIR PUTATIVE IMPLICATIONS FOR CLINICAL APPLICATIONS AND FOR STUDIES ON SPECIFIC HUMAN GENETIC DISEASES. RESULTS: SINCE THEIR DISCOVERY IN 2003, AFS CELLS HAVE BEEN SHOWN TO BE PLURIPOTENT WITH THE POTENTIAL TO FORM EMBRYOID BODIES. COMPARED TO ADULT STEM CELLS, INDUCED PLURIPOTENT STEM CELLS OR EMBRYONIC STEM CELLS, AFS CELLS HARBOUR A VARIETY OF ADVANTAGES, SUCH AS THEIR HIGH DIFFERENTIATION AND PROLIFERATIVE POTENTIAL, NO NEED FOR ECTOPIC INDUCTION OF PLURIPOTENCY AND NO SOMATIC MUTATIONS AND EPIGENETIC MEMORY OF SOURCE CELLS, AND NO TUMOURIGENIC POTENTIAL AND ASSOCIATED ETHICAL CONTROVERSIES, RESPECTIVELY. CONCLUSIONS: RECENTLY, THE RESULTS OF DIFFERENT INDEPENDENT STUDIES PROVIDED EVIDENCE THAT AFS CELLS COULD INDEED BE A POWERFUL TOOL FOR RENAL REGENERATIVE MEDICINE. 2012 12 5405 39 REGULATED EXPRESSION OF P210 BCR-ABL DURING EMBRYONIC STEM CELL DIFFERENTIATION STIMULATES MULTIPOTENTIAL PROGENITOR EXPANSION AND MYELOID CELL FATE. P210 BCR-ABL IS AN ACTIVATED TYROSINE KINASE ONCOGENE ENCODED BY THE PHILADELPHIA CHROMOSOME ASSOCIATED WITH HUMAN CHRONIC MYELOGENOUS LEUKEMIA (CML). THE DISEASE REPRESENTS A CLONAL DISORDER ARISING IN THE PLURIPOTENT HEMATOPOIETIC STEM CELL. DURING THE CHRONIC PHASE, PATIENTS PRESENT WITH A DRAMATIC EXPANSION OF MYELOID CELLS AND A MILD ANEMIA. RETROVIRAL GENE TRANSFER AND TRANSGENIC EXPRESSION IN RODENTS HAVE DEMONSTRATED THE ABILITY OF BCR-ABL TO INDUCE VARIOUS TYPES OF LEUKEMIA. HOWEVER, STUDY OF HUMAN CML OR RODENT MODELS HAS NOT DETERMINED THE DIRECT AND IMMEDIATE EFFECTS OF BCR-ABL ON HEMATOPOIETIC CELLS FROM THOSE REQUIRING SECONDARY GENETIC OR EPIGENETIC CHANGES SELECTED DURING THE PATHOGENIC PROCESS. WE UTILIZED TETRACYCLINE-REGULATED EXPRESSION OF BCR-ABL FROM A PROMOTER ENGINEERED FOR ROBUST EXPRESSION IN PRIMITIVE STEM CELLS THROUGH MULTILINEAGE BLOOD CELL DEVELOPMENT IN COMBINATION WITH THE IN VITRO DIFFERENTIATION OF EMBRYONAL STEM CELLS INTO HEMATOPOIETIC ELEMENTS. OUR RESULTS DEMONSTRATE THAT BCR-ABL EXPRESSION ALONE IS SUFFICIENT TO INCREASE THE NUMBER OF MULTIPOTENT AND MYELOID LINEAGE COMMITTED PROGENITORS IN A DOSE-DEPENDENT MANNER WHILE SUPPRESSING THE DEVELOPMENT OF COMMITTED ERYTHROID PROGENITORS. THESE EFFECTS ARE REVERSIBLE UPON EXTINGUISHING BCR-ABL EXPRESSION. THESE FINDINGS ARE CONSISTENT WITH BCR-ABL BEING THE SOLE GENETIC CHANGE NEEDED FOR THE ESTABLISHMENT OF THE CHRONIC PHASE OF CML AND PROVIDE A POWERFUL SYSTEM FOR THE ANALYSIS OF ANY GENETIC CHANGE THAT ALTERS CELL GROWTH AND LINEAGE CHOICES OF THE HEMATOPOIETIC STEM CELL. 2000 13 794 30 CELLULAR REPROGRAMMING IN BASIC AND APPLIED BIOMEDICINE: THE DAWN OF REGENERATIVE MEDICINE. FERTILIZATION TRIGGERS A CASCADE OF CELLULAR AND MOLECULAR EVENTS RESTORING THE TOTIPOTENT STATE AND THE POTENTIAL FOR ALL CELL TYPES. HOWEVER, THE PROGRAM QUICKLY DIRECTS DIFFERENTIATION AND CELLULAR COMMITMENT. UNDER THE GENETIC AND EPIGENETIC CONTROL OF THIS PROCESS, WADDINGTON LIKENED THIS TO A THREE-DIMENSIONAL LANDSCAPE WHERE CELLS COULD NOT ASCEND THE SLOPE OR TRAVERSE ONCE CANALIZED THUS LEADING TO CELL FATE DECISIONS AND THE PROGRESSIVE RESTRICTION OF CELLULAR POTENCY. BUT THIS IS NOT THE ONLY POSSIBLE OUTCOME AT LEAST EXPERIMENTALLY. SOMATIC CELL NUCLEAR TRANSFER AND OVEREXPRESSION OF KEY TRANSCRIPTION FACTORS TO GENERATE INDUCED PLURIPOTENT CELLS HAVE CHALLENGED THIS NOTION. THE RETURN TO PLURIPOTENCY AND THE REINSTATEMENT OF PLASTICITY AND HETEROGENEITY ONCE THOUGHT TO BE THE EXCLUSIVE REMIT OF THE DEVELOPING EMBRYO CAN NOW BE REPLICATED IN VITRO. THE FOLLOWING CHAPTER INTRODUCES SOME OF THESE IDEAS AND SUGGESTS THAT THE FUNDAMENTAL PRINCIPLES LEARNED MAY CONSTITUTE THE FIRST STEP TOWARD THE OPPORTUNITY FOR SPECIFIC TISSUE RENEWAL AND REPLACEMENT IN HEALTHY AGING AND THE TREATMENT OF CHRONIC DISEASES-THE AGE OF REGENERATIVE MEDICINE. 2015 14 735 24 CANCER STEM CELLS INDUCED BY CHRONIC STIMULATION WITH PROSTAGLANDIN E2 EXHIBITED CONSTITUTIVELY ACTIVATED PI3K AXIS. PREVIOUSLY, OUR GROUP HAS DEMONSTRATED ESTABLISHMENT OF CANCER STEM CELL (CSC) MODELS FROM STEM CELLS IN THE PRESENCE OF CONDITIONED MEDIUM OF CANCER CELL LINES. IN THIS STUDY, WE TRIED TO IDENTIFY THE FACTORS RESPONSIBLE FOR THE INDUCTION OF CSCS. SINCE WE FOUND THE LIPID COMPOSITION COULD BE TRACED TO ARACHIDONIC ACID CASCADE IN THE CSC MODEL, WE ASSESSED PROSTAGLANDIN E2 (PGE2) AS A CANDIDATE FOR THE ABILITY TO INDUCE CSCS FROM INDUCED PLURIPOTENT STEM CELLS (IPSCS). MOUSE IPSCS ACQUIRED THE CHARACTERISTICS OF CSCS IN THE PRESENCE OF 10 NG/ML OF PGE2 AFTER 4 WEEKS. SINCE CONSTITUTIVE AKT ACTIVATION AND PIK3CG OVEREXPRESSION WERE FOUND IN THE RESULTANT CSCS, OF WHICH GROWTH WAS FOUND INDEPENDENT OF PGE2, CHRONIC STIMULATION OF THE RECEPTORS EP-2/4 BY PGE2 WAS SUPPOSED TO INDUCE CSCS FROM IPSCS THROUGH EPIGENETIC EFFECT. THE BIOINFORMATICS ANALYSIS OF THE NEXT GENERATION SEQUENCE DATA OF THE OBTAINED CSCS PROPOSED NOT ONLY RECEPTOR TYROSINE KINASE ACTIVATION BY GROWTH FACTORS BUT ALSO EXTRACELLULAR MATRIX AND FOCAL ADHESION ENHANCED PI3K PATHWAY. COLLECTIVELY, CHRONIC STIMULATION OF STEM CELLS WITH PGE2 WAS IMPLIED RESPONSIBLE FOR CANCER INITIATION ENHANCING PI3K/AKT AXIS. 2022 15 1923 22 ENVIRONMENTAL EPIGENETIC MODIFICATIONS AND REPROGRAMMING-RECALCITRANT GENES. THE TERM "ENVIRONMENTAL EPIGENETIC MODIFICATIONS" REFERS TO ALTERATIONS IN PHENOTYPE TRIGGERED BY ENVIRONMENTAL STIMULI VIA EPIGENETIC MECHANISMS. EPIDEMIOLOGIC AND ANIMAL MODEL STUDIES SHOW THAT A SUBSET OF SUCH ENVIRONMENTAL EPIGENETIC MARKS MAY AFFECT SUSCEPTIBILITY TO CHRONIC DISEASES. A GROWING BODY OF EVIDENCE REGARDING INCOMPLETENESS OF REPROGRAMMING INDICATES THAT THE POTENTIAL RETENTION OF PATHOGENIC ENVIRONMENTAL EPIGENETICS IN HUMAN INDUCED PLURIPOTENT STEM CELLS (IPSCS) SHOULD BE SERIOUSLY CONSIDERED. GIVEN THIS POSSIBILITY, THE OPTIMIZATION OF METHODS FOR THE GENERATION OF HUMAN INDUC PLURIPOTENT STEM CELLS MAY REQUIRE THE IDENTIFICATION OF EPIGENETICALLY APPROPRIATE SOMATIC CELL SOURCES. SIMILARLY, TECHNIQUES FOR CONTROLLING EPIGENETIC MODIFICATION BY ENVIRONMENTAL FACTORS MAY ALSO PLAY A CRITICAL ROLE IN THE DEVELOPMENT OF EPIGENETICALLY STABLE SOURCES OF PLURIPOTENT STEM CELLS. 2010 16 2072 32 EPIGENETIC CONVERSION OF HUMAN ADULT BONE MESODERMAL STROMAL CELLS INTO NEUROECTODERMAL CELL TYPES FOR REPLACEMENT THERAPY OF NEURODEGENERATIVE DISORDERS. TISSUE-SPECIFIC STEM CELLS, SUCH AS BONE MARROW-DERIVED MESODERMAL STROMAL CELLS (MSCS), ARE THOUGHT TO BE LINEAGE RESTRICTED AND, THEREFORE, COULD ONLY BE DIFFERENTIATED INTO CELL TYPES OF THE TISSUE OF ORIGIN. SEVERAL RECENT STUDIES, HOWEVER, SUGGEST THAT THESE TYPES OF STEM CELLS MIGHT BE ABLE TO BREAK BARRIERS OF GERM LAYER COMMITMENT AND DIFFERENTIATE IN VITRO AND/OR IN VIVO INTO CELLS OF DIFFERENT TISSUES, SUCH AS NEUROECTODERMAL CELL TYPES. RECENTLY, PROTOCOLS FOR HIGH-YIELD GENERATION OF UNDIFFERENTIATED NEURAL STEM CELL (NSC)-LIKE CELLS FROM MSCS OF PRIMATE AND HUMAN ORIGIN WERE REPORTED. UNDIFFERENTIATED NSCS ARE COMMONLY USED AND ARE MORE SUITABLE FOR NEUROTRANSPLANTATION COMPARED WITH FULLY DIFFERENTIATED NEURAL CELLS, AS DIFFERENTIATED NEURAL CELLS ARE WELL KNOWN TO POORLY SURVIVE DETACHMENT AND SUBSEQUENT TRANSPLANTATION PROCEDURES. THESE HUMAN MSC-DERIVED NSC-LIKE CELLS (MSC-NSCS) GROW IN NEUROSPHERE-LIKE STRUCTURES AND EXPRESS HIGH LEVELS OF EARLY NEUROECTODERMAL MARKERS, BUT LOSE CHARACTERISTICS OF MSCS. IN THE PRESENCE OF SELECTED GROWTH FACTORS, HUMAN MSC-NSCS CAN BE DIFFERENTIATED INTO THE THREE MAIN NEURAL PHENOTYPES: ASTROGLIA, OLIGODENDROGLIA AND NEURONS. COMPARED WITH DIRECT DIFFERENTIATION OF HUMAN MSCS INTO MATURE NEURAL CELLS, THE CONVERSION STEP SEEMS TO BE ESSENTIAL TO GENERATE MATURE FUNCTIONAL NEUROECTODERMAL CELLS. THIS REVIEW DESCRIBES THE TECHNIQUES FOR THE CONVERSION OF HUMAN MSCS INTO NSCS AND SUMMARISES THE DATA ON EPIGENETIC CONVERSION OF HUMAN MSCS INTO IMMATURE NEUROECTODERMAL CELLS. THESE CELLS PROVIDE A POWERFUL TOOL FOR INVESTIGATING THE MOLECULAR MECHANISMS OF NEURAL DIFFERENTIATION, AND MIGHT SERVE AS AN AUTOLOGOUS CELL SOURCE TO TREAT ACUTE AND CHRONIC NEURODEGENERATIVE DISEASES. 2006 17 4436 17 MOLECULAR EVOLUTION OF CHRONIC MYELOID LEUKAEMIA. CHRONIC MYELOID LEUKAEMIA (CML) IS A CLONAL DISORDER OF THE PLURIPOTENT HAEMATOPOIETIC STEM CELL. THE TYPICAL TRIPHASIC COURSE OF CML STARTS WITH THE PREMALIGNANT CHRONIC PHASE INITIATED BY BCR-ABL HYBRID ONCOGENE FORMATION. SECONDARY GENETIC AND EPIGENETIC ABERRATIONS ACCOMPANY THE PROGRESSION TO THE ACCELERATED PHASE AND FATAL BLASTIC CRISIS. PROPERLY TIMED BONE MARROW TRANSPLANTATION IN ELIGIBLE PATIENTS CAN RESULT IN DURABLE REMISSIONS OR CURE. BOTH OF THESE STATES ARE OFTEN ACCOMPANIED BY A LONG-TERM PERSISTENCE OF QUIESCENT LEUKAEMIC CELLS. ACCORDINGLY, A "FUNCTIONAL CURE" (I.E. TUMOUR DORMANCY INDUCTION), RATHER THAN COMPLETE ERADICATION OF THE MALIGNANT CELLS, IS AN ADEQUATE THERAPEUTICAL GOAL. THE LEVEL OF THE RESIDUAL BCR-ABL-POSITIVE CLONES SHOULD BE MONITORED AND SALVAGE TREATMENT INITIATED WHENEVER THESE QUIESCENT LEUKAEMIC CELLS EXIT THEIR DORMANT STATE. 2001 18 3234 30 HEMATOPOIETIC AND CHRONIC MYELOID LEUKEMIA STEM CELLS: MULTI-STABILITY VERSUS LINEAGE RESTRICTION. THERE IS COMPELLING EVIDENCE TO SUPPORT THE VIEW THAT THE CELL-OF-ORIGIN FOR CHRONIC MYELOID LEUKEMIA IS A HEMATOPOIETIC STEM CELL. UNLIKE NORMAL HEMATOPOIETIC STEM CELLS, THE PROGENY OF THE LEUKEMIA STEM CELLS ARE PREDOMINANTLY NEUTROPHILS DURING THE DISEASE CHRONIC PHASE AND THERE IS A MILD ANEMIA. THE HALLMARK ONCOGENE FOR CHRONIC MYELOID LEUKEMIA IS THE BCR-ABLP210 FUSION GENE. VARIOUS STUDIES HAVE EXCLUDED A ROLE FOR BCR-ABLP210 EXPRESSION IN MAINTAINING THE POPULATION OF LEUKEMIA STEM CELLS. STUDIES OF BCR-ABLP210 EXPRESSION IN EMBRYONAL STEM CELLS THAT WERE DIFFERENTIATED INTO HEMATOPOIETIC STEM CELLS AND OF THE EXPRESSION IN TRANSGENIC MICE HAVE REVEALED THAT BCR-ABLP210 IS ABLE TO VEER HEMATOPOIETIC STEM AND PROGENITOR CELLS TOWARDS A MYELOID FATE. FOR THE TRANSGENIC MICE, GLOBAL CHANGES TO THE EPIGENETIC LANDSCAPE WERE OBSERVED. IN CHRONIC MYELOID LEUKEMIA, THE ABILITY OF THE LEUKEMIA STEM CELLS TO CHOOSE FROM THE MANY FATES THAT ARE AVAILABLE TO NORMAL HEMATOPOIETIC STEM CELLS APPEARS TO BE DEREGULATED BY BCR-ABLP210 AND CHANGES TO THE EPIGENOME ARE ALSO IMPORTANT. EVEN SO, WE STILL DO NOT HAVE A PRECISE PICTURE AS TO WHY NEUTROPHILS ARE ABUNDANTLY PRODUCED IN CHRONIC MYELOID LEUKEMIA. 2022 19 955 26 CHRONIC MYELOID LEUKEMIA: MECHANISMS OF BLASTIC TRANSFORMATION. THE BCR-ABL1 ONCOPROTEIN TRANSFORMS PLURIPOTENT HSCS AND INITIATES CHRONIC MYELOID LEUKEMIA (CML). PATIENTS WITH EARLY PHASE (ALSO KNOWN AS CHRONIC PHASE [CP]) DISEASE USUALLY RESPOND TO TREATMENT WITH ABL TYROSINE KINASE INHIBITORS (TKIS), ALTHOUGH SOME PATIENTS WHO RESPOND INITIALLY LATER BECOME RESISTANT. IN MOST PATIENTS, TKIS REDUCE THE LEUKEMIA CELL LOAD SUBSTANTIALLY, BUT THE CELLS FROM WHICH THE LEUKEMIA CELLS ARE DERIVED DURING CP (SO-CALLED LEUKEMIA STEM CELLS [LSCS]) ARE INTRINSICALLY INSENSITIVE TO TKIS AND SURVIVE LONG TERM. LSCS OR THEIR PROGENY CAN ACQUIRE ADDITIONAL GENETIC AND/OR EPIGENETIC CHANGES THAT CAUSE THE LEUKEMIA TO TRANSFORM FROM CP TO A MORE ADVANCED PHASE, WHICH HAS BEEN SUBCLASSIFIED AS EITHER ACCELERATED PHASE OR BLASTIC PHASE DISEASE. THE LATTER RESPONDS POORLY TO TREATMENT AND IS USUALLY FATAL. HERE, WE DISCUSS WHAT IS KNOWN ABOUT THE MOLECULAR MECHANISMS LEADING TO BLASTIC TRANSFORMATION OF CML AND PROPOSE SOME NOVEL THERAPEUTIC APPROACHES. 2010 20 5798 27 STEM CELLS AND LUNG REGENERATION. THE ABILITY TO REPLACE DEFECTIVE CELLS IN AN AIRWAY WITH CELLS THAT CAN ENGRAFT, INTEGRATE, AND RESTORE A FUNCTIONAL EPITHELIUM COULD POTENTIALLY CURE A NUMBER OF LUNG DISEASES. PROGRESS TOWARD THE DEVELOPMENT OF STRATEGIES TO REGENERATE THE ADULT LUNG BY EITHER IN VIVO OR EX VIVO TARGETING OF ENDOGENOUS STEM CELLS OR PLURIPOTENT STEM CELL DERIVATIVES IS LIMITED BY OUR FUNDAMENTAL LACK OF UNDERSTANDING OF THE MECHANISMS CONTROLLING HUMAN LUNG DEVELOPMENT, THE PRECISE IDENTITY AND FUNCTION OF HUMAN LUNG STEM AND PROGENITOR CELL TYPES, AND THE GENETIC AND EPIGENETIC CONTROL OF HUMAN LUNG FATE. IN THIS REVIEW, WE INTEND TO DISCUSS THE KNOWN STEM/PROGENITOR CELL POPULATIONS, THEIR RELATIVE DIFFERENCES BETWEEN RODENTS AND HUMANS, THEIR ROLES IN CHRONIC LUNG DISEASE, AND THEIR THERAPEUTIC PROSPECTS. ADDITIONALLY, WE HIGHLIGHT THE RECENT BREAKTHROUGHS THAT HAVE INCREASED OUR UNDERSTANDING OF THESE CELL TYPES. THESE ADVANCEMENTS INCLUDE NOVEL LINEAGE-TRACED ANIMAL MODELS AND SINGLE-CELL RNA SEQUENCING OF HUMAN AIRWAY CELLS, WHICH HAVE PROVIDED CRITICAL INFORMATION ON THE STEM CELL SUBTYPES, TRANSITION STATES, IDENTIFYING CELL MARKERS, AND INTRICATE PATHWAYS THAT COMMIT A STEM CELL TO DIFFERENTIATE OR TO MAINTAIN PLASTICITY. AS OUR CAPACITY TO MODEL THE HUMAN LUNG EVOLVES, SO WILL OUR UNDERSTANDING OF LUNG REGENERATION AND OUR ABILITY TO TARGET ENDOGENOUS STEM CELLS AS A THERAPEUTIC APPROACH FOR LUNG DISEASE. 2020