Principal Investigator: Malcolm Moos, MD, PhD
Office / Division / Lab: OTAT / DCGT / CTTB

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General Overview

Tissues and organs can be damaged by accident, battle trauma, or disease. Improved methods of repair, replacement, or regeneration of damaged tissues and organs are an important public health goal. Novel biological products containing living cells show great promise for use as therapies in these settings, but design, manufacture, and testing of these products has proven very challenging.

A major obstacle to successful development of cellular therapies has been great uncertainty about how to test these products to be sure they are safe and effective. Most of this testing will need to focus on the basic mechanisms cells use to control their behavior, especially the differentiation of immature cells (such as stem cells) to mature forms. We can do experiments with frog embryos that are not possible with mammals that teach us a great deal about these mechanisms. Using this approach, we have found several proteins that act as signals controlling certain aspects of cell differentiation.

We have used a variety of methods to identify these signals, including identification and detailed examination of biological activities and chemical analysis of the purified molecules that control those activities, DNA amplification by polymerase chain reaction (PCR, a technique for making millions of copies of single pieces of DNA for study), and computer-based mathematical analysis of these pathways and how they control tissue and organ development. We then test the effects of individual molecules that are over-expressed (too much of the molecule), expressed in the wrong place, or under-expressed. This provides us with a great deal of information about what a signaling molecule can do, and what processes it is essential for. We can then do additional experiments to see what known signal pathways the molecule interacts with.

This approach has identified molecules that are now being evaluated as therapeutic products and biomarkers (molecules whose presence reflects specific states of activity, disease, response to drugs, potency, and other characteristics of cells and tissues). Biomarkers will be very valuable tools for manufacturing engineered tissues and for testing products.

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Scientific Overview

Our objective is to identify signals and signal pathways critical for controlling cell fate decisions in order to develop improved methods for evaluating experimental cell-based products analytically both for process controls and release specifications that predict product performance reliably. The research program exploits a vertebrate embryology model that is particularly useful for identifying the key biological mechanisms controlling repair and regeneration and the interactions between them We focus on the medically critical but complicated process of joint development and perform detailed functional analyses of the proteins involved. We have identified several molecules that help control processes such as joint morphogenesis, blood development, and formation of the nervous system.

This work has also uncovered ways in which different proteins cooperate to achieve precisely localized control of tissue and organ development during the formation of complex structures such as the vertebrate joint, eye, or even overall body plan. We have identified both novel proteins (ADMP, CDMP1, CDMP2, FRZB) and novel functions for known proteins (SMOC, SPC7). We have used classical protein purification and protein microsequencing, degenerate PCR, and computational screens to identify molecules of interest. We then study their function and biological distribution in the experimentally tractable Xenopus embryo, relying heavily on gain-of-function and loss-of- function studies in which mRNA or antisense morpholino oligonucleotides, respectively, are microinjected in targeted regions of the embryo.

Finally, our approach has not only identified the novel molecules and functions mentioned previously, but also provided new insights into control of both the Bone Morphogenetic Protein and Wnt signaling pathways. Several of the molecules are being evaluated as therapeutic products, biomarkers for testing of cellular products, or reagents for use in tissue engineering.

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Publications

Sci Transl Med 2012 Aug 29;4(149):149fs31
FDA oversight of cell therapy clinical trials.
Au P, Hursh DA, Lim A, Moos MC Jr, Oh SS, Schneider BS, Witten CM

PLoS One 2012 June;7(6):e39380
A homolog of subtilisin-like proprotein convertase 7 is essential to anterior neural development in Xenopus.
Senturker S, Thomas JT, Mateshaytis J, Moos M Jr

Tissue Eng Part B Rev 2009 Dec;15(4):381-94
Developmental Engineering: A new paradigm for the design and manufacturing of cell based products. Part I: From three-dimensional cell growth to biomimetics of in vivo development.
Lenas P, Moos M Jr, Luyten FP

Tissue Eng Part B Rev 2009 Dec;15(4):395-422
Developmental engineering: a new paradigm for the design and manufacturing of cell-based products. Part II: from genes to networks: tissue engineering from the viewpoint of systems biology and network science.
Lenas P, Moos M, Luyten FP

J Biol Chem 2009 Jul 10;284(28):18994-9005
Xenopus SMOC-1 Inhibits Bone Morphogenetic Protein Signaling Downstream of Receptor Binding and Is Essential for Postgastrulation Development in Xenopus.
Thomas JT, Canelos P, Luyten FP, Moos M Jr

Trends Pharmacol Sci 2008 Dec;29(12):591-3
Stem-cell-derived products: an FDA update.
Moos M Jr

J Virol Methods 2008 Nov;153(2):111-9
Establishment of retroviral pseudotypes with influenza hemagglutinins from H1, H3, and H5 subtypes for sensitive and specific detection of neutralizing antibodies.
Wang W, Butler EN, Veguilla V, Vassell R, Thomas JT, Moos M, Ye Z, Hancock K, Weiss CD

Dev Biol 2007 Oct 1;310(1):129-39
Vg1 has specific processing requirements that restrict its action to body axis patterning centers.
Thomas JT, Moos M Jr

J Biol Chem 2006 Sep 8;281(36):26725-33
CDMP1/GDF5 has specific processing requirements that restrict its action to joint surfaces.
Thomas JT, Prakash D, Weih K, Moos M Jr