Source: UNIV OF HAWAII submitted to
ROLE OF MYOSTATIN (GDF-8)PRODOMAIN IN PROMOTING ANIMAL GROWTH
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0197535
Grant No.
(N/A)
Project No.
HAW00210-1017S
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2003
Project End Date
Sep 30, 2006
Grant Year
(N/A)
Project Director
Yang, J.
Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822
Performing Department
HUMAN NUTRITION, FOOD & ANIMAL SCIENCES
Non Technical Summary
Great economic challenges have prevented the Hawaii animal industry sustainability due to less competitive product price and high cost of operations. This project examines a key gene, myostatin, which negatively controls animal muscle growth. By reducing myostatin activity, this project explores a means of enhancing muscle growth and meat production in animals. Results from this research will be useful for promoting animal growth with efficient feed utilization and better meat quality.
Animal Health Component
(N/A)
Research Effort Categories
Basic
40%
Applied
40%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3033510104050%
3043520108030%
3053840102020%
Goals / Objectives
Animal industry is an important sector of diversified agriculture and economy in Hawaii. The livestock farm value is about 68 million dollars, and 10% of the production value comes from the beef industry. However, great economic challenges have prevented the industry sustainability in recent years due to less competitive product price and high cost of operations. The foundation of meat production is the skeletal muscle growth and development and fat deposition of animals. To circumvent the high cost of operations, improving feed efficiency through enhancing muscle growth and metabolic efficiency would be a sound scientific solution. Muscle growth is controlled by various growth factors and hormones. Myostatin gene (also called GDF-8) is recently identified as a dominant negative determinant of muscularity and muscle mass in beef cattle and mice. Previously, we demonstrated that myostatin prodomain is potent in promoting animal growth and meat production in transgenic mice. This project is designed to investigate how the prodomain down-regulate myostatin activity with myoblast cells and skeletal muscles from animals, as well as how the prodomain transgene affects animal fat deposition and feed efficiency. Furthermore, a technology of muscle gene transfer will be developed on the basis of myostatin prodomain DNA sequence. The objective of our research efforts is to understand the molecular regulation of myostatin activity, and to develop myostatin prodomain-based technologies for enhancing animal muscle growth. Therefore, this project can make a significant contribution to the improvement of production efficiency, competitive product prices and better quality for Hawaii animal industry.
Project Methods
We hypothesize that the prodomain-enhanced muscularity results from its depressing effects on myostatin activity, and direct intramuscular injection of prodomain DNA is an effective means of promoting animal muscle growth. This project initially investigates molecular interactions between myostatin and its prodomain, and metabolic interactions between muscle growth and fat deposition with muscle cell culture and established prodomain transgenic animals. We will be employing molecular biology and tissue culture techniques to study myostatin and prodomain interactions. Further molecular analysis will also be conducted in muscle samples from growing animals. To develop more effective technology for promoting animal growth, we will continuously develop muscle gene transfer technology based on the prodomain DNA sequence. Skeletal muscle-specific promoter and a highly efficient vector are prepared for building up the transgene construct. We will test the prodomain-based vector in young mice and pigs. Results from these approaches will reveal critical molecular interactions between myostatin and its prodomain, as well as metabolic interactions between muscle growth and fat deposition. This new knowledge is very useful for us to understand fundamentally animal production efficiency. The innovative muscle gene transfer technology development will have significant impacts on Hawaii, also the US meat production by its potential application for enhancing animal growth and efficient feed utilizations.

Progress 10/01/03 to 09/30/06

Outputs
Growth performance is fundamental to all aspects of animal agriculture. Fast animal growth rate and muscle buildup increases feed efficiency and meat quality. Myostatin plays a robust, negative role in controlling muscle mass. A disruption of myostatin function by transgenic expression of its propeptide (the 5'region, 866 nucleotides) results in significant muscle growth (Yang et al., 2001. Mol. Rep. Dev 60: 351-361). Studies from myostatin and the propeptide transgene mRNA indicated that myostatin mRNA was detected at day 10.5 postcoitum in fetal mice. Its level remained low, but increased by 180% during the postnatal fast-growth period (day 0-10). To study the effects of dietary fat on muscle growth and adipose tissue fat deposition in the transgenic mice, we challenged the mice with a high-fat diet (45% kcal fat) for 21 weeks. Transgenic mice showed 24-50% further enhancement of growth on the high-fat diet compared to the normal-fat diet (P=0.004) from 17 to 25 weeks of age. The total mass of the main muscles of transgenic mice showed a 27 % increase on the high-fat diet compared to the normal-fat diet (P=0.004), while the white adipose tissue mass of the transgenic mice was not significantly different from that of wild-type mice fed a normal-fat diet (P=0.434). We employed immunohistochemistry procedures to study myostatin expression in muscle tissue. The results confirmed high myostatin propetide expression in transgenic mice with normal expression mature myostatin level. Interestingly, hematoxylin & eosin staining of the muscles identified active status myogenesis in adult transgenic muscles. This research provides molecular and cellular evidences for enhanced muscle growth through depressing myostatin by its propeptide. Genetic or cellular manipulation of myostatin gene by its prodomain would be useful for promoting animal growth, as well as for efficient feed utilization and better meat quality.

Impacts
Animal agriculture is important for Hawaii economy and conservation of agricultural land. To improve animal production systems, this project examines a key muscle gene, namely myostatin. By reducing myostatin activity through transgenic expression of its prodomain cDNA sequence, this project explores a means of enhancing muscle growth for livestock animals. Results from this research will not only help us to understand the molecular mechanisms of muscle growth, but also be useful in developing new tools for promoting animal growth performance and better meat quality. In addition, these results also demonstrate that disruption of myostatin function by its propeptide shifted dietary fat utilization toward muscle tissues with minimal effects on adiposity, suggesting that enhancing muscle growth by myostatin propeptide or other means during the early developmental stage may serve as an effective means for obesity prevention.

Publications

  • Yang J. and Zhao B. 2006. Postnatal Expression of Myostatin Propeptide cDNA Maintained High Muscle Growth and Normal Adipose Tissue Mass in Transgenic Mice Fed a High-fat Diet. Molecular Reproduction and Development 73: 462-469.
  • Yang J and Zhao B. 2006. Effects of enhanced muscle mass on body fat deposition and insulin sensitivity. The FASEB Journal 20(4): A168.
  • Zhao B, Wall RJ, Baracos VE, Dunn MA, Theriault A, Yang J. 2006. Coordinated Patterns Of Gene Expression For Skeletal Muscle Hypertrophy In Transgenic Mice Expressing Myostatin Propeptide. Plant & Animal Genomes XIV Conference, P755. Available: http://www.intl-pag.org/pag/14/abstracts/PAG14_P755.html


Progress 10/01/04 to 09/30/05

Outputs
The understanding of growth performance is fundamental to all aspects of animal agriculture. Fast animal growth rate and muscle buildup increases feed efficiency and meat quality. This project is developed from the recent identification of the critical gene of myostatin, which is known to control muscle growth through negative actions. Our previous studies demonstrated that myostatin prodomain is potent in promoting animal growth and meat production in transgenic mice by disrupting myostatin function. This project is designed to understand the mechanism of the myostatin prodomain and to explore a means of enhancing muscle growth and meat production in animals through manipulation of myostatin activity. In the past year, we investigated molecular interactions between myostatin and its prodomain, and metabolic interactions between muscle growth and fat deposition. Results indicated that myostatin mRNA was detected at day 10 postcoitum in fetal mice. Its level remained low, but increased by 180% during the postnatal fast-growth period. An early, high-level postnatal expression of the transgene was identified as being responsible for a highly muscled phenotype. Animal experiment with high-fat diet demonstrated that disruption of myostatin function by its prodomain shifted dietary fat utilization toward muscle tissues with minimal effects on adiposity. These results strongly suggest that depression of myostatin by its prodomain is an effective means for building up muscle mass. Genetic or cellular manipulation of myostatin gene by its prodomain would be useful for promoting animal growth, as well as for efficient feed utilization and better meat quality.

Impacts
A sustainable animal agriculture is important for Hawaii economy and conservation of agricultural land. To improve animal production systems, this project examines a key muscle gene, namely myostatin. By reducing myostatin activity through transgenic expression of its prodomain cDNA sequence, this project explores a means of enhancing muscle growth for livestock animals. Results from this research will not only help us to understand the molecular mechanisms of muscle growth, but also be useful in developing new tools for promoting animal growth performance and better meat quality. In the long term, this project will generate an impact on innovative technology development for efficient animal production.

Publications

  • Yang, J., Zhao, B. and Wall, R.J. 2005. Myostatin prodomain transgene significantly improves dietary fat utilization for animal muscle growth. Journal of Animal Science. 83 (supplement 1):387.
  • Zhao, B., Wall, R.J. and Yang, J. 2005. Transgenic expression of myostatin propeptide prevents diet-induced obesity and insulin resistance. Biochemical and Biophysical Research Communications. 337:248-55.


Progress 10/01/03 to 09/30/04

Outputs
Animal industry is an important sector of diversified Hawaii agriculture. To improve animal production efficiency, we are interested in studying muscle growth by focusing on myostatin gene. Myostatin is a dominant negative determinant of muscle mass in beef cattle, mice and human. We have demonstrated that myostatin prodomain (the cDNA sequence from the start code to the RSRR cleavage site) is potent in promoting growth and muscle mass (Yang et al., 2001). The purpose of this project is to determine the effects of transgenic expression of the prodomain on muscle growth and fat deposition. Significant research results have been obtained from both animal trials and laboratory analysis. The highlights of the accomplishments include: 1) detections of myostatin and transgene mRNA over developmental stages; and 2) further enhanced muscle growth of transgenic mice on high-fat diet. Research data have been presented to several scientific conferences, and summarized to two manuscripts for publications. The myostatin prodomain transgenic animals were generated with the MLC-pro domain cDNA construct. A colony of the mice was established at the animal facility of the university. Expression of endogenous myostatin was measured in fetuses, neonates and adults by Northern blotting analysis. By comparing transgene expressions in high and low transgenic lines, we concluded that the transgene mRNA accumulation matched very well with rate of animal growth. In the high-growth line, transgenic mice were 20 to 46% heavier than littermate controls from day 1 to 4 months. To study fat deposition and feed efficiency in the transgenic animals, we carried out a 2 x 2 factorial experimental design by two types of diet with same total calorie energy level-normal and high fat diet, and two genotypes-transgenic and non-transgenic control. Results from this experiment showed that transgenic mice significantly grew faster, and produced more muscle mass than non-transgenic littermate controls, in either high-fat or normal fat diet. The total carcass weight of male transgenic mice increased by 50% compared with no-transgenic controls, and the individual major muscles of transgenic mice were 47-100% more heavier than the control animals. However, the adipose tissue in transgenic mice showed no significant difference from control animals in normal fat diets. When animal received high-fat diet, the weight of major adipose tissues were extremely significantly different between transgenic and control animals (P<0.001). High-fat diet induced control mice obesity and diabetes with 1.7-2.2 times more fat tissues than transgenic mice. Results from this experiment clearly demonstrated that animals carrying the prodomain transgene not only had dramatic growth and enhanced muscle mass, but also showed strong resistance to high-fat diet-induced fat deposition.

Impacts
Great economic challenges have prevented Hawaii's animal industry sustainability due to less competitive product price and high feed cost. This project examines a key muscle gene, namely myostatin. Myostatin negatively controls animal muscle growth. By reducing myostatin activity through transgenic expression of its prodomain cDNA sequence, this project explores a means of enhancing muscle growth for livestock animals. Results from this research will not only help us to understand the molecular mechanisms of muscle growth, but also be useful in developing new tools for promoting animal growth performance and better meat quality. This project will generate an impact on innovative technology development for efficient animal production in the US agriculture.

Publications

  • Yang, J., Ratovitski, T., Brady, J.P., Solomon, M.B., Wells, K.D. and Wall, R.J. 2001. Expression of myostatin pro domain results in muscular transgenic mice. Molecular Reproduction and Development. 60:351-361.
  • Yang, J., Ratovitski, T., Brady, J.P., Solomon, M.B., Wells, K.D., Pursel, V.G. and Wall, R.J. 2001. Expression of a myostatin pro domain transgene increases muscle mass and decreases body fat. Transgenic Research. 10:563.
  • Yang, J. and Xiong, Y. 2003. Genetic manipulations of dominant muscularity genes for efficient pig production. The Proceedings of International Conferences on Pig Production (Beijing China).Page: 67-71.
  • Yang, J., Kim, Y.S. and Wall, R.J. 2004. Myostatin and its Prodomain transgene expression. Plant and Animal Genome XII Conference, Page 293 (Abstract). 2004, San Diego.


Progress 10/01/02 to 09/30/03

Outputs
No progress to report. This project was initiated on October 1, 2003.

Impacts
No impact to report. This project was initiated on October 1, 2003.

Publications

  • No publications reported this period