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Faculty Index
 Dr. Becich
Dr. D. Becker
Dr. J. Becker
Dr. Billiar
Dr. Blair
Dr. Bostwick
Dr. Bowser
Dr. Chaillet
Dr. Chang
Dr. Cheng
Dr. Chu
Dr. Clemens
Dr. DeFrances
Dr. Delude
Dr. Demetris
Dr. Dong
Dr. Donnenberg
Dr. Gandhi
Dr. Giannoukakis
Dr. Gnarra
Dr. Grandis
Dr. Hebda
Dr. Huard
Dr. Kaminski
Dr. Katyal
Dr. Kelavkar
Dr. Klunk
Dr. Kulich
Dr. Lagasse
Dr. Latimer
Dr. Luyuan Li
Dr. Yong Li
Dr. Youhua Liu
Dr. Lokshin
Dr. Luo
Dr. Lyons-Weiler
Dr. Monga
Dr. Mars
Dr. Michalopoulos
Dr. Ochoa
Dr. O'Keefe
Dr. Oltvai
Dr. Oury
Dr. Pflug
Dr. Piganelli
Dr. Saunders
Dr. Shapiro
Dr. Stolz
Dr. Strom
Dr. Surti
Dr. Vodovotz
Dr. Wang
Dr. Wells
Dr. Wenzel
Dr. Wiley
Dr. Wu
Dr. Yin
Dr. Zarnegar
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Yong Li, Assistant Professor
MD, Shanghai Second Medical University, China 1993
PhD, Chongqing Third Medical University, China 1996
Email: yongli@pitt.edu
Research Interest:
1. Dedifferentiation and adult stem cells
The objective of this project is to examine adult stem cells, such as those of skin and muscle, as a tool to repair injured and congenitally diseased tissues (muscle, tendon, spinal cord, and others) and determine the potency and viability of various potential dedifferentiation stimulating compounds in vitro and in vivo. In Dr. Li's previous work, he has already observed some growth factors that were able to stimulate dedifferentiation in injured skeletal muscle. Using gene therapy and cell transplantation techniques, Dr. Li will investigate whether it is possible to take advantage of the dedifferentiation process inducible in mammalian skeletal muscle tissue to reconstruct the limb of another vertebrate (newt and salamander) model. The overall goal of this project is to increase the number of stem cell-like cells made available from the skin and skeletal muscle pool. The human body contains a large amount of easily accessible skin and skeletal muscle that is the likely source of numerous populations of adult stem cells that have an inherent capacity to differentiate into different phenotypic lineages and regenerate various tissues, including skeletal muscle, the spinal cord, various nerve cells, and liver. To be able to more fully comprehend and control this process and the intricacies of signaling involved would be of exceptionally important clinical value.
2. Fibrosis in skeletal muscular system
Amphibians, such as newts and salamanders can rebuild a limb after injury. However, injured mammalian tissue, including that of humans, is usually replaced with fibrotic scar tissue at the end of the healing process. This project's objective is to determine the mechanism(s) behind dedifferentiation in amphibians, and ascertain the relationship(s) between dedifferentiation and fibrotic scar tissue formation. To date, Dr. Li has already made some key findings pertaining to fibrosis (i.e., scar tissue formation) and its role in inhibiting muscle healing. Because scar tissue often replaces damaged myofibers, fibrosis is likely a contributing factor in the tendency for muscle injury recurrence. Dr. Li and his team have demonstrated, for the first time, the central role of TGF-¦Â1 in skeletal muscle fibrosis. Based upon Dr. Li's histological and physiological findings in this area, his subsequent research has shown that the use of anti-fibrotic agents, such as decorin, suramin, relaxin, and ¦Ã-INF (which negate the effects of TGF-¦Â1), can reduce muscle fibrosis and improve muscle healing. However, injuries cannot always be treated before fibrosis occurs, especially in the case of some chronic diseases in which scar tissue is formed prior to therapy. In muscles suffering from trauma, scar tissue forms in a time-dependent manner that subsequently inhibits muscle regeneration, and weakens the injured muscle, making it more susceptible to re-injury. Muscle scarring also poses a significant problem to Duchenne muscular dystrophy (DMD) patients, whose muscles can be replete with scar tissue, making them very weak by their teenage years. Dr. Li's project aims to examine the role of MMPs (matrix-metalloproteinases), to digest scar tissue after fibrosis has already occurred, thus enhancing muscle cell migration, fusion, regeneration, and improving the overall process of muscle healing.
Recent Publication
- Li Y, Huard J. Muscle derived stem cell transdifferentiate into myofibroblast in injured muscle. American J Pathology. 2002; 161 (3): 895-907.
- Huard J, Yokoyama T, Pruchnic R, Qu Z, Li Y, Lee JY, Somogyi G, de Groat WC, Chancellor MB. The use of muscle derived stem cells for urological dysfunction. Gene Therapy 2002; 9(23): 1617-1626.
- Chan YS, Li Y, Horaguchi T, Foster W, Somogi G, Fu FH, Huard J. The antifibrotic effects of suramin in injured skeletal muscle after laceration. J Apply Physiology 2003; 95:771-780.
- Foster W, Li Y, Arvydas Usas, George Somogyi, Huard J. gamma-INF as an antifibrotic agent in skeletal muscle. J Orthopeadic Research 2003;21:798-804.
- Sato K, Li Y, Foster W, Fukushima K, Badlani N, Nodachi N, Usas A, Fu FH, Huard J. Improvement of muscle healing through enhancement of muscle regeneration and prevention of fibrosis. Muscle & Nerve 2003; 28(3):365-372.
- Li Y, Foster W, Deasy BM, Chan YS, Prisk V, Tang Y, Cummins J, Huard J. TGF-beta1 induces the differentiation of myogenic cells into fibrotic cells in injured skeletal muscle: a key event in muscle fibrogenesis. American J Pathology 2004;164(3):1007-1019.
- Chan YS, Li Y, Horaguchi T, Foster W, Somogi G, Fu FH, Huard J. The use of suramin, an antifibrotic agent, to improve muscle recovery after strain injury. Am J Sport Medicine 2005; 33(1): 43-51.
- Li Y, Negishi S, Sakamoto M, Arvydas Usas, Huard, J. The use of relaxin improves healing in injured muscle. Annals of N. Y. Academic Science. 2005; 1041:395-398.
- Chen X, Mao Z, Liu S, Liu H, Wang X, Wu H, Wu Y, Zhao T, Fan W, Li Y, Yew DT, Kindler PM, Li L, He Q, Qian L, Wang X, Fan M. Dedifferentiation of Adult Human Myoblasts Induced by CNTF In Vitro. Molecular Biology of Cell. 2005;16(7):3140-51. Epub 2005 Apr 20.
- Negishi S, Li Y, Usas A, Ryosuke K, Foster W, Fu FH, Huard J. The effect of relaxin treatment in skeletal muscle injuries. Am J Spots Medicine first published on September 12, 2005 as doi:10.1177/0363546505278304
- Shen W, Li Y, Tang Y, Cummins J, Huard J. NS398, a cylooxygenase-2 specific inhibitor, delayed skeletal muscle healing by decreaseing regneration and promoting fibrosis. American J Pathology 2005;167:(4): 1105-1117.
- Shen W, Prisk V, Li Y, Foster W, Cummins J, Fu F, Huard J. Inhibited skeletal muscle healing in cyclooxygenase-2 gene deficiency mice, the roles of PGE2 and PGF2a in myofiber fusion. J App Physiol 2006 (June 15, 2006 online print)
- Li Y, Li J, Foster W, Tang Y, Xiao X, Huard J. Decorin promotes muscle cell differentiation and muscle regeneration. Molecular Therapy (Accepted) 2007.
- Matsuura T, Li Y, Giacobino JP, Fu FH, Huard J. Fast to slow myofiber type conversion during repair of mouse soleus: relationship between myofiber type conversion and PGC-1 expression. Journal of Orthopaedic Research. (Accepted) 2007.
- Bedair H, Liu TT, Kaar J, Shown B, Russell A, Huard J, Li Y. Matrix Metalloproteinase (MMP) Therapy Improves Muscle Healing. Journal of Applied Physiology (Accepted) 2007.
- Zhu JH*, Li Y*, Shen W, Qiao CP, Ambrosio F, Lavasani M, Nozaki M, Branca MF, Huard J. Relationships between TGF- 1, Myostatin, and decorin: Implications for skeletal muscle fibrosis. J Bio Chem (Accepted) 2007. *First two authors equally contributed to this paper.
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