Day :
- Biobank ethics, Stem Cell Biomarkers, Neurobank
Location: Webinar
Chair
Helieh S Oz
University of Kentucky Medical Center, USA
Session Introduction
Jean-Marc Lemaitre
Saint Eloi Hospital, France
Title: Exploring strategies for cell rejuvenation and tissue regeneration: iPSC reprogramming as a unique opportunity to understand and cure aging
Biography:
Jean-Marc Lemaitre has completed his PhD in Molecular and Cellular Biology of Development and Senior Scientist since 2014. He was awarded in 2006 for an AVENIR INSERM Team program on aging and is currently Deputy Director at the Institute of Regenerative Medicine and Biotherapy (IRMB), the leader of INSERM research team and Director of a stem cell facility CHU (SAFE-iPSC). He was invited as speaker for 48 national and international conferences and seminars in France and abroad in the last 5 years.
Abstract:
Many of the pathologies that could benefit from regenerative stem cell-based therapies are associated to aging. Emerging evidences indicates that adult stem cells exhibit functional shortcomings, including pronounced shifts in the types of mature effector cells produced as well as alterations in self-renewal capacity. Many intrinsic or extrinsic stress are able to accelerate the exhaustion of the proliferative capacity of stem cells or differentiated progenitors towards an ultimate senescencelike cell cycle arrest. Important and specific epigenetic modifications have been observed during this process, likely driving a specific gene expression –signature of cellular aging, and little is known about changes in large-scale genome organization during this aging process and or in different during senescence induced situations and its relationship with genetic instability. To further analyses this process and the relationship between replicative stress and chromatin reorganization, we followed the reorganization of chromatin dynamics features associated with senescence induction as well as the associated changes of the DNA replication program (Riviera-Mulia et al., 2017, Ogrunc et al., 2016, Prieur et al., 2016). To further understand, the interplay between genetics and epigenetics in tissue aging and to unravel molecular barriers, preventing cell rejuvenation of the age-related cellular physiology, we developed reprogramming strategies of somatic cells into induced pluripotent stem cells (iPSCs) to erase the hallmarks of cellular aging. Although this strategy provides a unique opportunity to derive patientspecific stem cells with potential application in autologous tissue replacement, limitation was revealed for elderly individuals, due to senescence described as a barrier to reprogramming that could drive genetic instability. To overcome this barrier and improve tissue regeneration, we developed an optimized reprogramming strategy that caused efficient reversing of cellular senescence and aging through reprogramming towards pluripotency. We demonstrated that iPSCs derived from senescent and centenarian fibroblasts have reset all the hallmarks of cellular aging, as telomere size, gene expression profiles, oxidative stress and mitochondrial metabolism, and are undistinguishable from hESC. Finally, we further demonstrate that re-differentiation, led to rejuvenated cells with a reset cellular physiology maintaining genetic stability, defining a new paradigm for human cell rejuvenation (Milhavet and Lemaitre 2014, Venables et al., 2013, Lapasset et al. 2011). Then we applied this knowledge to develop iPSC models for premature aging syndromes with high risk of genetic instability, to further explore the relationship between pathological and physiological aging. We will present and discuss data concerning opportunities and limits of using the iPSC technology for modelling pathologies involving replication stress, leading to senescence and ageing and genetic instability (Riviera-Mulia et al., 2017, Bouckenheimer et al., 2016, Lemey et al., 2016, Besnard et al., 2012, 2014).
Tojan B Rahhal
University of Missouri, USA
Title: Pulmonary delivery of butyrylcholinesterase as a model protein to the lung
Biography:
Tojan B Rahhal is an Adjunct Assistant Professor in Bioengineering and the Director of Diversity and Outreach Initiatives at the University of Missouri-Columbia in the College of Engineering. She graduated from North Carolina State University with a BS in Biomedical Engineering. She went on to pursue a PhD in Pharmaceutical Sciences at the University of North Carolina at Chapel Hill (UNC-Ch), working in the lab of Dr. Joseph M. DeSimone. Her research focused on Engineering PRINT Particles for Pulmonary Delivery of Therapeutics and examined the effect of particle parameters (size, shape, composition, and surface chemistry) on residence time, cellular interactions, and immune responses in the lungs. Her work addresses the need for more efficient delivery of active therapeutics/biologics using dry powders that allow for monodisperse aerosolization and accurate deposition in the lungs for treatment of pulmonary diseases. Her work has been published in Molecular Pharmaceutics and Nanomedicine: Nanotechnology, Biology, and Medicine.
Abstract:
Pulmonary delivery has great potential for delivering biologics to the lung if the challenges of maintaining activity, stability, and ideal aerosol characteristics can be overcome. To study the interactions of a biologic in the lung, we chose butyrylcholinesterase (BuChE) as our model enzyme, which has application to use as a bioscavenger protecting against organophosphate exposure or for using with pseudocholinesterase deficient patients. In mice, orotracheal administration of free BuChE resulted in 72 h detection in the lungs and 48 h in the broncheoalveolar lavage fluid (BALF). Free BuChE administered to the lung of all mouse backgrounds (Nude, C57BL/6, and BALB/c) showed evidence of an acute cytokine (IL6, TNF-α, MIP2, and KC) and cellular immune response that subsided within 48 h, indicating relatively safe administration of this non-native biologic. We then developed a formulation of BuChE using Particle Replication in Non-Wetting Templates (PRINT). Aerosol characterization demonstrated biologically active BuChE 1 μm cylindrical particles with a mass median aerodynamic diameter of 2.77 μm, indicative of promising airway deposition via dry powder inhalers (DPI). Furthermore, particulate BuChE delivered via dry powder insufflation showed residence time of 48 h in the lungs and BALF. The in vivo residence time, immune response, and safety of particulate BuChE delivered via a pulmonary route, along with the cascade impaction distribution of dry powder PRINT BuChE, showed promise in the ability to deliver active enzymes with ideal deposition characteristics. These findings provide evidence for the feasibility of optimizing the use of BuChE in the clinic; PRINT BuChE particles can be readily formulated for use in DPIs, providing a convenient and effective treatment option.
Fumio Arai
Kyushu University, Japan
Title: The novel mesenchymal stromal niche cell in the bone marrow endosteum
Biography:
Fumio Arai is a Professor at the Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University. He has completed his PhD from Meikai University and Post-doctoral studies from Keio University School of Medicine. His research interest is in studying the mechanisms of the cell fate regulation of HSCs at the single cell level for the establishment of the system that can expand HSCs.
Abstract:
Hematopoietic stem cells (HSCs) are responsible for blood cell production throughout the lifetime of individuals. Interaction of HSCs with their supportive microenvironmental niche, which is composed of cellular components located around stem cells, facilitate the signaling networks that control the balance between self-renewal and differentiation. HSCs maintain a quiescent state in the bone marrow, where they anchor to specialized niches along the endosteum (the border between the bone and the BM) and in perivascular sites adjacent to the endothelium. The cells in the endosteal niche are a heterogeneous population regarding their degree of differentiation and accompanying functions. In this study, we further characterized the endosteal niche cell populations by using the single-cell gene expression analysis and identified a small subpopulation in ALCAM+Sca-1– osteoblastic cell fraction that expressed pluripotent stem cell markers. Furthermore, this subpopulation of ALCAM+Sca-1– cells specifically expressed Cdh2. Also, this newly identified subpopulation could differentiate into osteoblast, adipocyte, and chondrocyte, and showed the gene expression pattern that closes to ES cells rather than other bone marrow MSC populations. We also evaluated the function of ALCAM+Sca-1–Cdh2+ cells and found that have the potential to maintain the self-renewal activity of HSCs. These data suggest that ALCAM+Sca-1–Cdh2+ cells are mesenchymal stromal cells with niche cell activity for HSCs.