Estudos com células tronco (CT) têm despertado grande interesse devido ao seu promissor potencial terapêutico. Neste contexto, as CT mesenquimais (CTm) representam uma alternativa para o tratamento de diversas patologias em diferentes órgãos, inclusive o rim e as glomerulopatias que o acometem. As doenças glomerulares constituem uma freqüente causa de doença renal crônica e se caracterizam por apresentar proteinúria. Neste processo, os podócitos são células que apresentam um papel crucial, sendo que as podocitopatias se associam com o aparecimento de proteinúria e desenvolvimento de esclerose glomerular. A obtenção de um modelo de podocitopatia através da administração de aminonucleosídeo de puromicina (PAN), permite a melhor compreensão dessas células altamente diferenciadas que não possuem potencial de proliferação ou regeneração. O presente projeto teve como objetivo estabelecer o modelo experimental de nefropatia crônica induzida por PAN associado à nefrectomia unilateral (UniNx) para induzir lesões glomerulares mais exuberantes e, neste modelo experimental, avaliar o efeito da infusão de CTm derivadas da medula óssea. Ratos Wistar (n=52) foram divididos em três grupos: Controle (UniNx), PAN (PAN+UniNx) e PAN+CTm (PAN+UniNx+CTm). As CTm foram inoculadas na região subcapsular renal no dia 0 e os animais foram sacrificados após 30 e 60 dias. O efeito da infusão das CTm no tecido renal foi avaliado através de parâmetros clínicos e laboratoriais, além de análise histológica, imunohistoquímica, microscopia eletrônica e PCR em tempo real. Paralelamente, o projeto analisou a diferenciação in vitro de CTm em podócitos através do estímulo com colágeno tipo IV e através de cocultura de glomérulos isolados de ratos com CTm. A diferenciação celular das CTm foi analisada por citometria de fluxo, imunocitoquímica e PCR em tempo real para genes de proteínas podocitárias. No modelo in vivo foi possível observar a presença de CTm até 15 dias após a inoculação na região subcapsular renal. As CTm foram capazes de diminuir significativamente a proteinúria e a albuminúria com 30 e 60 dias, assim como a pressão arterial aos 60 dias. Não houve diferença nos valores de creatinina, uréia sérica, glomeruloesclerose e fibrose intersticial entre o grupo PAN e o grupo PAN+CTm. As CTm foram responsáveis pela diminuição significativa da fusão dos pedicelos à microscopia eletrônica, com melhora da expressão relativa de WT1 aos 60 dias e melhora parcial da expressão gênica de nefrina, podocina e sinaptopodina. A expressão proteica de WT1 também foi significativamente maior no grupo PAN+CTm em comparação ao grupo PAN. Além disso, houve melhora significante da expressão relativa de IL-4 e IL-10, e diminuição de IL-1? e TNF-? no grupo tratado. Ainda, as CTm promoveram aumento significativo da expressão gênica de VEGF aos 60 dias. Nos resultados in vitro não houve diferenciação das CTm em podócitos quando cultivadas com colágeno IV, assim como a cocultura com glomérulos não proporcionou alteração na expressão de marcadores de superfície das CTm. Concluímos que a terapia celular com CTm foi capaz de induzir proteção renal caracterizada por diminuição da proteinúria, da albuminúria e da pressão arterial, associado a menor fusão dos pedicelos, maior expressão gênica de proteínas podocitárias e de expressão celular de WT1. As citocinas inflamatórias IL-1?, TNF-?, IL-4 e IL-10, em conjunto com o VEGF, foram os possíveis mediadores responsáveis por estes resultados / Stem cells (SC) have emerged as a potential therapeutic approach for several diseases. In this context, the mesenchymal SC (mSC) are considered an alternative for the treatment of kidney diseases such as glomerulopathies. Glomerular diseases are an important cause of chronic kidney disease (CKD) and are characterized by proteinuria. In this process, the podocytes are cells that have a critical role, and the podocytopathies are associated with the onset of proteinuria and glomerular sclerosis. The achievement of a podocytopathy model through administration of puromycin (PAN) allows a better understanding of these highly differentiated cells which do not have the potential for proliferation or regeneration. The aim of the present study was to establish an experimental model of chronic nephropathy induced by PAN associated with unilateral nephrectomy (UniNx), to induce early and marked glomerular lesions and, in this experimental model, to evaluate the effect of bone marrow mSC infusion. Wistar rats (n=52) were randomly divided into three groups: Control (UniNx), PAN (PAN+UniNx) and PAN+mSC (PAN+UniNx+mSC). mSC were inoculated into the subcapsular renal region on day 0, and the animals were sacrificed after 30 and 60 days. The mSC infusion effects in renal tissue were evaluated by clinical and laboratory parameters, histology, immunohistochemistry, electron microscopy and real-time PCR. In parallel, we analyzed whether mSC could differentiate in vitro into podocytes through stimulation with collagen type IV or by means of co-culture of isolated rat glomeruli with mSC. The cell differentiation was analyzed by flow cytometry, immunocytochemistry and real-time PCR. In the in vivo model, mSC were detected until 15 days after inoculation in the renal subcapsular region. mSC were able to significantly reduce the proteinuria and albuminuria with 30 and 60 days, as well as blood pressure at 60 days. There was no difference in the values of creatinine, BUN, glomerulosclerosis and interstitial fibrosis between the groups PAN and PAN+mSC. The treated group showed lower effacement of foot process by electron microscopy, with significant improvement in the relative expression of WT1 in 60 days and partial improvement of nephrin, podocyn and synaptopodin. The WT1 protein expression was also significantly higher in the PAN+mSC group compared to the PAN group. In addition, mSC treatment significantly reduced gene expression of IL-1? and TNF-?, as well as increased the expression of IL-4 and IL-10. At 60 days mSC promoted significant increase of VEGF relative expression. In vitro results, mSC cultived with collagen type IV did not show differentiation to podocytes and the co-culture with glomeruli provided no change in expression of mSC surface markers. In conclusion, mSC therapy in the PAN model was able to induce renal protection characterized by the reduction of albuminuria, proteinuria and blood pressure, associated with a lower effacement of foot process, increased gene expression of podocytes proteins and cellular expression of WT1. Inflammatory cytokines IL-1?, TNF-?, IL-4 and IL-10 associated with VEGF were the probable mediators of these results, promoting podocyte protection

Les hépatocytes humains adultes en culture primaire (HHCP) ont de nombreuses applications en physiopathologie hépatique, en pharmacologie et en biothérapie, mais sont limitées par leur faible disponibilité. Les cellules souches embryonnaires humaines (hES) sont une source prometteuse pour l'obtention d'hépatocytes en grande quantité. Nous avons développé un modèle in vitro de différenciation de hES en hépatocytes en reproduisant toutes les étapes de l'ontogenèse hépatique. Au cours de la différenciation, l'expression de 41 gènes marqueurs du foie a été étudiée et comparée aux HHCP, au foie fœtal et aux progéniteurs hépatiques issus du foie adulte. Les résultats démontrent qu'au bout de 21 jours de différenciation, les cellules souches embryonnaires différenciées en hépatocytes (hES-Hep) ont atteint un état de maturation équivalente aux hépatocytes fœtaux aux alentours de 20 semaines de gestation. L'expression forcée du xénorécepteur CAR dans les hES-Hep a induit l'expression des gènes de la détoxification et la biotransformation de midazolam, un substrat de CYP3A4. Ces résultats pourront contribuer au développement de cultures de hES-Hep comme alternative aux HHCP pour les études du métabolisme des xénobiotiques et pour la thérapie cellulaire. / Primary cultures of human adult hepatocytes (PCHH) have widespread potential applications in liver physiopathology , pharmacology, and cell-based therapies, but are currently limited by poor availability. Human embryonic stem cells (hES) are a promising source for the generation of hepatocytes in large quantities. In this study, we differentiated hES into hepatocytes by mimicking in vitro the various stages of hepatic ontogenesis. We analyzed the expression of a panel of 41 liver marker genes in hepatocyte-like cells derived from hES (hES-Hep) in comparison with PCHH, fetal liver and progenitors obtained from adult liver. The data revealed that after 21 days of differentiation ES-Hep are representative of fetal hepatocytes at around 20 weeks of gestation. The forced expression of the xenoreceptor CAR in hES-Hep induced the expression of detoxification genes as well as the biotransformation of midazolam, a substrate of CYP3A4. These results may contribute to the development of hES-Hep cultures as an alternative to PCHH for studies of xenobiotic metabolism and for cell-based therapies.

Oshima N, Yamada Y, Nagayama S, Kawada K, Hasegawa S, et al. (2014) Induction of Cancer Stem Cell Properties in Colon Cancer Cells by Defined Factors. PLoS ONE 9(7): e101735. doi:10.1371/journal.pone.0101735 / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18547号 / 医博第3940号 / 新制||医||1006(附属図書館) / 31447 / 京都大学大学院医学研究科医学専攻 / (主査)教授 千葉 勉, 教授 野田 亮, 教授 武藤 学 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Injury, aging, and congenital disabilities of the muscular and neural systems impose a significant burden on patients and their families. Due to the tissue’s limited regenerative capacity, effective treatment interventions for restoring progressive damage is still lacking. Cell replacement therapy is primarily limited by the restricted supply of viable donor cells and variable graft survival. For addressing these limitations, we propose new strategies to obtain a target cell of interest from an autologous cell source. Herein, we engineer cell fate decisions by 1) harnessing host microenvironment and the CRISPR/dCas9-mediated transcriptional activation system to promote myogenesis of human endothelial progenitor cells (EPCs); and 2) employing substrate-mediated biophysical cues with soluble factors (biochemical cues) to drive cell commitment to neuronal lineages. For the first strategy, we hypothesized that therapeutic cells could be obtained in situ by employing the CRISPR/dCas9 system to engineer cell fate in the host tissue. Using this system, we transactivated MYOD1, a master regulator for myogenesis, to directly reprogram primary EPCs to skeletal myoblasts (SkMs). EPCs were chosen as a cell source for their easy accessibility, high proliferation, and potential contribution to regenerate vasculature and musculature tissue. The early myogenic commitment of EPCs was confirmed in vitro by MYOD1 expression, which yielded a 230-fold higher induction than the original EPCs. These cells were then transplanted for assessing their therapeutic efficacy in myotoxin-induced muscle injury model in immunodeficient mice. A one-month post-injury study resulted in the integration of induced SkMs to the injured host tissue, promotion of neoangiogenesis, and reduction in fibrotic scar formation. These findings indicate that CRISPR/Cas9-mediated target gene activation can be achieved in situ to accelerate muscle regeneration after myotoxin-induced damage. For the second strategy, we utilized both soluble and insoluble factors to convert the cell fate of neural stem/progenitor and somatic cells to various neuronal lineages, including motor neurons (MNs) and dopaminergic (DA) neurons. For soluble factors, cells were exposed to various biochemical factors, inspired by the neuronal niche environs during the natural developmental process. For insoluble factors, the conductive graphene substrate was used to support the endogenous electrical signal between neurons for enhancing the neuronal phenotypes and their functionality. We postulated that exposing the cells to these collective stimuli in vitro can alter their intrinsic signaling pathway to tailor their fate to neuronal lineages. To test the hypothesis, neural stem/progenitor and somatic cells were cultured on various substrates with or without electroactive graphene and aligned patterns. After two weeks to one month of cell fate induction in the chemically defined conditions, our results implied that cell adhesion, survival, neurite outgrowth, and maturation were facilitated on the electroactive substrates with aligned patterns compared to the control platforms. Taken together, our results in this dissertation demonstrate the feasibility of tailoring the donor cell fates within or across the germ layers. We achieved this by employing a transcriptional gene activation system and tunable microenvironmental cues elicited by soluble (chemical and growth factors) and insoluble (physical cues from the substrate) factors. Utilizing such strategies hold great promise for elucidating the optimal conditions to guide cell fate to target lineages. This work provides a rational basis for establishing a robust protocol and an in vitro culture platform to module cell fate decisions that could help realize the autologous cell-based therapy for muscular and neurodegenerative diseases.

This article provides a brief review of the pathophysiology of osteoarthritis and the ontogeny of chondrocytes and details how physical exercise improves the health of osteoarthritic joints and enhances the potential of autologous chondrocyte implants, matrix-induced autologous chondrocyte implants, and mesenchymal stem cell implants for the successful treatment of damaged articular cartilage and subchondral bone. In response to exercise, articular chondrocytes increase their production of glycosaminoglycans, bone morphogenic proteins, and anti-inflammatory cytokines and decrease their production of proinflammatory cytokines and matrix-degrading metalloproteinases. These changes are associated with improvements in cartilage organization and reductions in cartilage degeneration. Studies in humans indicate that exercise enhances joint recruitment of bone marrow-derived mesenchymal stem cells and upregulates their expression of osteogenic and chondrogenic genes, osteogenic microRNAs, and osteogenic growth factors. Rodent experiments demonstrate that exercise enhances the osteogenic potential of bone marrow-derived mesenchymal stem cells while diminishing their adipogenic potential, and that exercise done after stem cell implantation may benefit stem cell transplant viability. Physical exercise also exerts a beneficial effect on the skeletal system by decreasing immune cell production of osteoclastogenic cytokines interleukin-1β, tumor necrosis factor-α, and interferon-γ, while increasing their production of antiosteoclastogenic cytokines interleukin-10 and transforming growth factor-β. In conclusion, physical exercise done both by bone marrow-derived mesenchymal stem cell donors and recipients and by autologous chondrocyte donor recipients may improve the outcome of osteochondral regeneration therapy and improve skeletal health by downregulating osteoclastogenic cytokine production and upregulating antiosteoclastogenic cytokine production by circulating immune cells.

Ischemic brain injury represents a major cause of death worldwide with limited treatment options with a narrow therapeutic window. Accordingly, novel treatments that extend the treatment from the early neuroprotective stage to the late regenerative phase may accommodate a much larger number of stroke patients. To this end, stem cell-based regenerative therapies may address this unmet clinical need. Several stem cell therapies have been tested as potentially exhibiting the capacity to regenerate the stroke brain. Based on the long track record and safety profile of transplantable stem cells for hematologic diseases, bone marrow-derived mesenchymal stromal cells or mesenchymal stromal cells have been widely tested in stroke animal models and have reached clinical trials. However, despite the translational promise of MSCs, probing cell function remains to be fully elucidated. Recognizing the multi-pronged cell death and survival processes that accompany stroke, here we review the literature on MSC definition, characterization, and mechanism of action in an effort to gain a better understanding towards optimizing its applications and functional outcomes in stroke. / National Institutes of Health / Revisión por pares

Maintenance of the hematopoietic system is dependent upon the proper regulation and orchestrated functions of the hematopoietic stem cell (HSC) pool. A number of extrinsic signaling pathways and intrinsic regulators have been found to regulate HSC processes. However a full understanding of the ability of HSC to balance the processes of self-renewal, quiescence, and lineage specification is not yet clear. We therefore set out to identify novel HSC regulators by comparative gene expression analysis of whole genome transcriptomes generated for long-term (LT)-HSC (Hoechst low/- Lin- Sca1+ cKit+ CD34-), short-term (ST)-HSC (Hoechst low/- Lin- Sca1+ cKit+ CD34+), and non-HSC (Hoechst+) of the bone marrow. These studies identified IGF2 as one of the most differentially expressed genes within LT-HSC, suggesting a potential role for IGF2 in the regulation of HSC. Using a combination of lentiviral-mediated overexpression and knockdown experiments, we found IGF2 to confer enhanced self-renewal in vitro and in vivo. Overexpression of IGF2 resulted in an increased percentage of multi-lineage colonies within colony-forming unit (CFU) assays without affecting lineage specification. In vivo, serial bone marrow transplantation revealed that IGF2 within HSC enhances short-term and long-term donor contribution. Analysis of the expression of key cell cycle regulators revealed that IGF2 induced upregulation of p57 expression specifically within HSC. This upregulation could be attributed to differences in the methylation status of the p57 promoter in HSC compared to other progenitor and mature blood cell populations. p57, a member of the Cip/Kip family of cyclin dependent kinase inhibitors, has recently been shown to be required for the regulation of HSC quiescence and long-term self-renewal. Analysis of bone marrow obtained from primary and secondary transplant recipients showed that overexpression of IGF2 resulted in an increased percentage of quiescent HSC. Treatment of HSC overexpressing IGF2 with LY294002, a PI3K-Akt inhibitor, prevented IGF2-mediated upregulation of p57 expression. These findings demonstrate that within HSC, IGF2 induces p57 expression through activation of the PI3K-Akt pathway to regulate HSC quiescence. We have identified a novel role for IGF2 in HSC function, providing new insights into the biology of HSC and opening potential platforms for the development of better therapies involving HSC-mediated hematopoietic reconstitution.

Indiana University-Purdue University Indianapolis (IUPUI) / Human cord blood (CB) derived circulating endothelial colony forming cells (ECFCs) display a hierarchy of clonogenic proliferative potential and possess de novo vessel forming ability upon implantation in immunodeficient mice. Since survival of ECFC post-implantation is a critical variable that limits in vivo vasculogenesis, we tested the hypothesis that activation of Notch signaling or co-implantation of ECFC with human platelet lysate (HPL) would enhance cultured ECFC vasculogenic abilities in vitro and in vivo. Co-implantation of ECFCs with Notch ligand Delta-like 1 (DL1) expressing OP9 stromal cells (OP9-DL1) decreased apoptosis of ECFC in vitro and increased vasculogenesis of ECFC in vivo. The co-culture of ECFC with HPL diminished apoptosis of ECFC by altering the expression of pro-survival molecules (pAkt, pBad and Bcl-xL) in vitro and increased vasculogenesis of human EC-derived vessels both in vitro and in vivo. Thus, activation of the Notch pathway by OP9-DL1 stromal cells or co-implantation of ECFC with HPL enhances vasculogenesis and augments blood vessel formation by diminishing apoptosis of the implanted ECFC. The results from this study will provide critical information for the development of a cell therapy for limb and organ re-vascularization that can be applied to recovery of ischemic tissues in human subjects.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20663号 / 医博第4273号 / 新制||医||1024(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 藤渕 航, 教授 木村 剛, 教授 岩田 想 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21166号 / 農博第2292号 / 新制||農||1061(附属図書館) / 学位論文||H30||N5140(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 今井 裕, 教授 久米 新一, 准教授 南 直治郎 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM