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Publications in Nuclear Reprogramming by NOMIS researchers

NOMIS Researcher(s)

Published in

June 25, 2020

Parkinson’s disease is characterized by loss of dopamine neurons in the substantia nigra1. Similar to other major neurodegenerative disorders, there are no disease-modifying treatments for Parkinson’s disease. While most treatment strategies aim to prevent neuronal loss or protect vulnerable neuronal circuits, a potential alternative is to replace lost neurons to reconstruct disrupted circuits2. Here we report an efficient one-step conversion of isolated mouse and human astrocytes to functional neurons by depleting the RNA-binding protein PTB (also known as PTBP1). Applying this approach to the mouse brain, we demonstrate progressive conversion of astrocytes to new neurons that innervate into and repopulate endogenous neural circuits. Astrocytes from different brain regions are converted to different neuronal subtypes. Using a chemically induced model of Parkinson’s disease in mouse, we show conversion of midbrain astrocytes to dopaminergic neurons, which provide axons to reconstruct the nigrostriatal circuit. Notably, re-innervation of striatum is accompanied by restoration of dopamine levels and rescue of motor deficits. A similar reversal of disease phenotype is also accomplished by converting astrocytes to neurons using antisense oligonucleotides to transiently suppress PTB. These findings identify a potentially powerful and clinically feasible approach to treating neurodegeneration by replacing lost neurons.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

NOMIS Researcher(s)

Despite the profound and rapid advancements in reprogramming technologies since the generation of the first induced pluripotent stem cells (iPSCs) in 2006[1], the molecular basics of the process and its implications are still not fully understood. Recent work has suggested that a subset of TFs, so called “Pioneer TFs”, play an important role during the stochastic phase of iPSC reprogramming [2-6]. Pioneer TFs activities differ from conventional transcription factors in their mechanism of action. They bind directly to condensed chromatin and elicit a series of chromatin remodeling events that lead to opening of the chromatin. Chromatin decondensation by pioneer factors progressively occurs during cell division and in turn exposes specific gene promoters in the DNA to which TFs can now directly bind to promoters that are readily accessible[2, 6]. Here, we will summarize recent advancements on our understanding of the molecular mechanisms underlying reprogramming to iPSC as well as the implications that pioneer Transcription Factor activities might play during different lineage conversion processes.

Research field(s)
Health Sciences, Biomedical Research, Biochemistry & Molecular Biology

NOMIS Researcher(s)

October 1, 2014

The generation of human induced pluripotent stem cells (iPS) has raised enormous expectations within the biomedical community due to their potential vast implications in regenerative and personalized medicine. However, reprogramming to iPS is still not fully comprehended. Difficulties found in ascribing specific molecular patterns to pluripotent cells (PSCs), and inherent inter-line and intra-line variability between different PSCs need to be resolved. Additionally, and despite multiple assumptions, it remains unclear whether the current in vitro culturing conditions for the maintenance and differentiation of PSCs do indeed recapitulate the developmental processes observed in vivo. As a consequence, basic questions such as what is the actual nature of PSCs remain unanswered and different theories have emerged in regards to the identity of these valuable cell population. Here we discuss on the published theories for defining PSC identity, the implications that the different postulated models have for the reprogramming field as well as speculate on potential future directions that might be opened once a precise knowledge on the nature of PSCs is accomplished.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

NOMIS Researcher(s)

Published in

September 5, 2013

Since the initial discovery that OCT4, SOX2, KLF4, and c-MYC overexpression sufficed for the induction of pluripotency in somatic cells, methodologies replacing the original factors have enhanced our understanding of the reprogramming process. However, unlike in mouse, OCT4 has not been replaced successfully during reprogramming of human cells. Here we report on a strategy to accomplish this replacement. Through a combination of transcriptome and bioinformatic analysis we have identified factors previously characterized as being lineage specifiers that are able to replace OCT4 and SOX2 in the reprogramming of human fibroblasts. Our results show that it is possible to replace OCT4 and SOX2 simultaneously with alternative lineage specifiers in the reprogramming of human cells. At a broader level, they also support a model in which counteracting lineage specification networks underlies the induction of pluripotency. © 2013 Elsevier Inc.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

NOMIS Researcher(s)

Published in

September 1, 2013

Somatic cell nuclear reprogramming is opening new doors for the modeling of human disease phenotypes in vitro, the identification of novel therapeutic compounds and diagnostic factors as well as future autologous cell replacement therapies. Despite the potential that reprogramming technologies bring, there are remaining concerns preventing their broad application in the short-term. One of them is the safety concern associated with the use of stem cell derivatives, those generated by reprogramming or even when embryonic stem cells are employed. Here we summarize the current knowledge in the field of stem cells and reprogramming with a particular focus on the pitfalls preventing rapid translation of stem cell technologies into the clinic. We discuss the most recent findings on immunogenicity and tumorigenicity of reprogrammed cells. We additionally provide an overview on the potential applications that reprogramming approaches might bring to the immunological field and elaborate on the use of induced pluripotent stem cells (iPSCs) with pre-arranged immune receptors for the development of future immunotherapeutic approaches. The use of reprogramming approaches can represent and provide groundbreaking strategies previously unachievable for stem cell engineering aimed at modulating immune responses. In summary, we provide an overview on the different topics related to the use of stem cells and highlight the most provocative, yet perhaps currently underappreciated, aspect of combining immunological and reprogramming strategies for the treatment of human disease. © 2013 Elsevier B.V.

Research field(s)
Health Sciences, Clinical Medicine, Immunology

NOMIS Researcher(s)

Published in

March 7, 2013

Finding a cure for cardiovascular disease remains a major unmet medical need. Recent investigations have started to unveil the mechanisms of mammalian heart regeneration. The study of the regenerative mechanisms in lower vertebrate and mammalian animal models has provided clues for the experimental activation of proregenerative responses in the heart. In parallel, the use of endogenous adult stem cell populations alongside the recent application of reprogramming technologies has created major expectations for the development of therapies targeting heart disease. Together, these new approaches are bringing us closer to more successful strategies for the treatment of heart disease. © 2013 Elsevier Inc.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology