UCR

Cell Biology and Neuroscience



Nicole zur Nieden


Nicole zur Nieden
Phone: (951) 827-3818
Fax: (951) 827-3087
Office Location: 1113 Biological Sciences
Office Hours: , -
Email: nicole.zurnieden@ucr.edu

Nicole I. zur Nieden

Assistant Professor
Dipl.-Biol. (MSc) 1999 - University of Bochum, Germany
Dr. rer. nat. (PhD) 2002 - Ruhr-University Bochum, Germany
Postdoctoral Fellow 2002-2006 - University of Calgary, Alberta, Canada

Biography

The pluripotent potential of embryonic stem cells (ESCs) is frequently exploited to study organogenesis in vitro. The lab has previously carried out critical research in the mouse model concentrating on expansion and differentiation of ESCs and identification of essential regulatory pathways. We have established protocols for the in vitro differentiation of murine ESCs into mineralized osteoblasts (Fig. 1) and matrix-secreting chondrocytes. Not only did these analyses reveal the fact that functioning skeletal cell types had been generated from ESCs, but also resulted in a comprehensive analysis of the expression of bone marker genes and osteo-specific enzymatic activity. From these analyses we hypothesize that osteogenesis in ESCs traverses through at  least four distinct phases: proliferation (I), early osteogenic specification (II), matrix deposition (III) and mineralization (IV).

Using the ESC model, a major goal of our research group is a) to embark on deepening the knowledge of stem cell specification into osteogenic lineages, b) to understand molecular regulators of normal bone development and thereby c) to deduce novel therapeutic targets, which could be aimed at during disease intervention in the clinic.

figure1
Figure 1: Osteoblasts differentiated from murine ESCs. Differentiation was induced with beta-glycerophosphate, ascorbic acid and 1,25-OH2 vitamin D3 from culture day 5 to 30 [zur Nieden et al., 2003]. (Left) Alizarin Red S and (Middle) von Kossa stain for mineralized calcium. Bars = 160 ┬Ám. (Right) Osteocalcin immuno-positive cells (left panel) appear black in phase contrast (right panel).

Soluble factors influence the Wnt/CatnB pathway during differentiation. Further work in the lab has shown that nitric oxide (NO) agonists or antagonists may both support osteogenesis in ESCs depending on the timing of their administration. NO donor administration aids mineralization and maturation of the ESCs in late differentiation (phase IV), whereas inhibition of the NO pathway supports specification into an osteoprogenitor state (phase III). Our  studies have shown that a critical phase exists during osteogenesis, in which the addition of NO agonists appears to be necessary for the formation of what would be the equivalent of the primitive streak in vivo, which occurs around day 3 of in vitro differentiation (phase II). Extended analyses have shown that NO influences the localization and expression level of beta-catenin (CatnB), a key player in the Wnt signaling pathway. Timely controlled fluctuations in the CatnB level seem to be essential for osteogenic differentiation and maybe even for the specification of other lineages (Fig. 2).

figure2
Fig. 2: Regulation of ESC differentiation through CatnB. Activation or blockage of nuclear CatnB activity controls lineage decisions. The duration of the specific signal seems to play a role in the transcriptional activation of lineage-specific transcription factors [Davis and zur Nieden, 2008].

Elucidating the role of non-canonical Wnts during differentiation. While CatnB is the key effector in the canonical Wnt signaling cascade, non-canonical Wnts (i.e. Wnt5a) have been shown to block CatnB activity. Many of the associated proteins of the non-canonical Wnt pathway have been well characterized in an isolated function as they can interact and signal through other developmental pathways. The key components of the three non-canonical pathways so far identified are CamKII, JNK and PKC. As we have established, treatment with Wnt5a during phase III of in vitro development can support the osteogenic differentiation path. We now aim to investigate, which of the three suggested subpathways is involved in the osteogenic process. First data suggests that proliferation of progenitors and the onset of mineralization are modulated by PKCbeta, whereas CamKII seems to modulate cAMP levels and expression of mature bone markers.

Oxidative stress modulates the Wnt/CatnB axis. In contrast to murine ESCs, which can be reasonably well expanded in vitro, primate ESCs tend to differentiate spontaneously in culture. The successful expansion of ESCs therefore might be eased by mimicking the conditions ESCs experience in their natural niche. The lab has begun to explore the role of oxidative stress in ESC maintenance and differentiation. Preliminary results suggest that high glucose levels, which are currently routinely used in ESC culture media, adversely affect stem cell characteristics by altering Wnt/CatnB signaling.

MicroRNAs regulate the Wnt/CatnB axis during the osteogenic process. Being signaling molecules, Wnts and NO exert their effects by being translated into intracellular signals ultimately activating the transcriptional machinery. Intriguingly, most of these external factors not only regulate osteogenic processes, but can also be involved in the cellular differentiation into other lineages, such as neurogenesis. Consequently, it is likely that another (master) level of regulation may exist in addition to these external stimuli.

In order to identify such an osteogenic master regulator, the lab also studies microRNAs (miRNAs). These RNA molecules are short 20-22 nucleotide RNA structures that are negative regulators of gene expression in more than 30% of protein-coding genes in a variety of eukaryotic organisms. Additionally, miRNAs seem to be involved in regulating stem cell organization affecting self-renewal, proliferation and differentiation. The lab has so far successfully identified 25 miRNAs, which are differentially regulated during the first 8 days of the osteogenic developmental path. Current studies characterize the role of these miRNAs in more depth and have identified new target molecules, which may be malfunctioning in degenerative and congenital bone diseases.

HONORS AND AWARDS

  • 2011 Regent's Faculty Fellowship
  • 2010 TRDRP New Investigator Award
  • 2008 1st Poster Prize, Fraunhofer Institute for Cell Therapy and Immunology 
  • 2006, 2007 Alumni Award, Canadian Stem Cell Network Centres of Excellence
  • 2007 Nobel Laureate Meeting, Lindau, Germany, Nominated and Selected Participant
  • 2007 IQ Innovation Price Central Germany, Top Ten Finalist
  • 2005 Leica Meritorious Performance Award, University of Calgary
  • 2004 Best Poster Presentation, Canadian Stem Cell Network Annual General Meeting
  • 2003 - 2005 Post-doctoral Fellowship, Alberta Heritage Foundation for Medical Research

Publications

 Original articles

  • Trettner S, Findeisen A, Taube S, Horn P, Sasaki E, zur Nieden NI (2014). Osteogenic induction from primate embryonic stem cells cultured in feeder-dependent and feeder-independent conditions. Osteoporosis Int, in press
  • Keller KC, Rodriguez B, zur Nieden NI (2014). Suspension culture of embryonic stem cells. Crit Rev Eukaryot Gene Expr, in press
  • Ding H, Keller KC, Martinez IKC, Geransar RM, zur Nieden KO, Nishikawa SG, Rancourt DE, zur Nieden NI (2012). NO/beta-catenin crosstalk modulates primitive streak formation prior to embryonic stem cell osteogenic differentiation. J Cell Sci 125(Pt22)5564-77
  • Torrez LB, Perez Y, Yang J, zur Nieden NI, Klassen H, Liew CG (2012). Derivation of neural progenitors and retinal pigment epithelium from common marmoset and human pluripotent stem cells. Stem Cells Int 2012: 417865 
  • Kim M, Garant KA, zur Nieden NI, Alain T, Loken SD, Urbanski SJ, Forsyth PA, Rancourt DE, Lee PWK, Johnston RN (2011). Attenuated reovirus displays oncolysis with reduced host toxicity. Br J Cancer 104(2): 2090-299
  • Dienelt A, zur Nieden NI. Hyperglycemia impairs skeletogenesis from embryonic stem cells by affecting osteoblast and osteoclast differentiation. Stem Cells Dev, in press
  • zur Nieden NI, Davis LA, Rancourt DE (2010). Monolayer cultivation of osteoprogenitors shortens duration of the embryonic stem cell test while reliably predicting developmental osteotoxicity. Toxicology 277(1-3), 66-73
  • zur Nieden NI, Davis LA, Rancourt DE (2010). Evaluating Developmental Osteotoxicity in the Embryonic Stem Cell Test. Step I: Comparison of Three Novel Endpoints. Toxicol Appl Pharmacol 247(2), 91-97
  • Taiani JT, Krawetz RJ, zur Nieden NI, Wu YE, Kallos MS, Matyas JR, Rancourt DE (2010). Stirred Suspension Bioreactors Promote Embryonic Stem Cell Pluripotency in the Absence of LIF. Stem Cells Dev 19(7), 989-998
  • Quintana L, zur Nieden NI, Semino CE (2009). Morphogenetic and regulatory mechanisms during developmental chondrogenesis. Tissue Eng Part B Rev 15(1), 29-41
  • Davis LA, zur Nieden NI (2008). Mesodermal fate decisions of a stem cell: the Wnt switch. Cell Mol Life Sci 65(17), 2658-2674
  • Meng GL*, zur Nieden NI*, Liu SY, Cormier JT, Kallos MS, Rancourt DE. (2008). Properties of murine embryonic stem cells maintained on human foreskin fibroblasts without LIF. Mol Reprod Dev 75(4), 614-622 (*Authors contributed equally to this study)
  • zur Nieden NI, Price FD, Davis LA, Everitt R, Rancourt DE (2007). Gene array analysis on mixed ES cell populations: a biphasic role for beta-catenin in osteogenesis. Mol Endocrinol 21(3), 674-685
  • zur Nieden NI, Cormier JT, Kallos MS, Rancourt DE (2007). Murine embryonic stem cells maintain pluripotency after long-term culture in suspension bioreactors. J Biotechnol 129(3), 421-432
  • zur Nieden NI, Kempka G, Rancourt DE, Ahr HJ (2005). Induction of chondro-, osteo- and adipogenesis in embryonic stem cells by bone morphogenetic protein-2: Effect of co-factors on differentiating lineages. BMC Developmental Biology 5, 1-15
  • zur Nieden NI, Kempka G, Ahr HJ (2003). In vitro differentiation of embryonic stem cells into mineralized osteoblasts. Differentiation 71, 18-27

Books and book chapters (selected)

  • Satoorian TS, zur Nieden NI (2013). Metabolism in cancer cells and pluripotent stem cells. In: Hayat MA (ed), Stem Cells and Cancer Stem Cells, Vol9, pp83-92
  • Keller KC, zur Nieden NI (2011). Osteogenesis from pluripotent stem cells: neural crest or mesodermal origin? In: Kallos MS (ed), Embryonic Stem Cells - Differentiation and Pluripotent Alternatives. InTech ISBN 978-953-307-632-4, pp323-348
  • zur Nieden NI (2011). Embryonic stem cells for osteo-degenerative diseases. Methods Mol Biol. 690, 1-30
  • Kuske B, Savkovic V, zur Nieden NI (2011). Improved media compositions for the differentiation of embryonic stem cells into osteoblasts and chondrocytes. Methods Mol Biol. 690, 195-215
  • Trettner S, Seeliger A, zur Nieden NI (2011). Embryoid body formation in suspension: recent advances in automated bioreactor technology. Methods Mol Biol. 690, 135-149
  • Davis LA, Dienelt A, zur Nieden NI (2011). Absorption based assays for the identification of skeletal cell types. Methods Mol Biol. 690, 255-272
  • zur Nieden NI. Embryonic stem cells for the prediction of developmental toxicity in pharmacological screening. In: Conrad K, Lehman W, Sack U, Schedler U (eds). Multiparameteranalytics - Methods, Applications, Perspectives. Pabst Science Publishers, Lengerich 2008, pp 198-220. Article in German

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