Examining the Relative Contributions of Genes, Diet, and the Gut Microbiome to the Development of Obesity and Diabetes

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PI: Laura C. Bridgewater

This project began as a collaboration with Dr. Julianne Grose in MMBIO to study the effect of PAS kinase on diabetes and obesity in a mouse model system. Due to our initial findings, the study has grown to include Dr. Ben Bickman in PDBIO (an expert in metabolism) and Dr. Scott Weber in MMBIO (an immunologist). We have found that PAS kinase knockout mice have an increased metabolic rate—not only in their overall system but also specifically in skeletal muscle. Metabolic rate can have a profound influence on the immune system, so we began working with Dr. Weber to measure the types of immune cells present in wild type vs. PAS kinase knockout mice. These experiments revealed a shortage of macrophages in the PAS kinase mutants. We have also found that PAS kinase plays a role in cell cycle progression and phase distribution, suggesting a potential role in cancer. Interestingly, we found that the increased metabolic rate in PAS kinase mutant mice does not produce a lower overall body weight when mice consume a high fat/high sugar diet. This observation suggests that mutation of PAS kinase may alter the ratio of lean muscle to adipose tissue, a hypothesis that we will shortly begin testing using magnetic resonance imaging (MRI). IACUC approval to perform MRI scans on the mice from this project was recently obtained. The gut microbiota portion of the project is still underway, because of the way that metagenomic next generation sequencing is performed.

Our system allows for the simultaneous sequencing of about 350 samples for the same cost as one sample (several thousand dollars), so we won’t perform any gut microbiota sequencing until the final fecal samples are collected and microbial genomic DNA is isolated from each sample. 16S rRNA genes will then be amplified, amplicons tagged with Illumina index primers, and all the samples combined into a sequencing library and sequenced together in a single run. This last phase of the project will be completed next year. Due to the success of the other aspect of the project and the clear indications that PAS kinase plays a fundamentally important role in regulating metabolism, Dr. Julianne Grose has been able to obtain NIH funding that will pay for the remainder of the project. We expect four PAS kinase-related publications to come directly from this project—one on gut microbiota, one on muscle metabolic rate, one on immune function, and one on cell cycle. These papers are not included in the list below, because data collection is still underway.

Below are lists of papers published and of posters presented at scientific meetings, which have resulted from mentoring in my lab since this MEG grant was awarded in 2013. BYU student authors are in bold to emphasize the number of students who have benefited from mentoring in the Bridgewater Lab.

Publications

  1. Bridgewater, L.C., Zhang, C., Wu, Y., Zhang, Q., Hu, W., Wang, J., Li, S., Zhao, L. “Gender-­‐based differences in host behavior and gut microbiota composition in response to high fat diet and stress in a mouse model.” (in preparation).
  2. Beatty, A., Bowden, A.E., Bridgewater, L.C. “Development of complex dynamic intervertebral disc bioreactor.” (in preparation).
  3. Cordner, R.D., Friend, L.N., Mayo, J.L., Stallings, C., Young, P., Miles, D., Badgley, C., Wallmann, A., Ventura, J.S., Chidsey, B.A., Rogers, A.C., Edwards, J.G., & Bridgewater, L.C. “The nuclear variant of bone morphogenic protein 2 (nBMP2) affects cognition in a mouse model.” (in revision).
  4. Long, W., Xue, Z., Zhang, Q., Feng, Z., Bridgewater, L.C., Wang, L., Zhao, L., Pang, X. “Differential responses of gut microbiota to the same prebiotic formula in oligotrophic and eutrophic batch fermentation systems.” Scientific Reports 5:13469 doi: 10.1038/srep13469 http://www.nature.com/articles/srep13469 (2015).
  5. Olsen, D.S., Goar, W.A., Nichols, B.A., Bailey, K.T., Christensen, S. L., Merriam, K.R., Reynolds, P.R., Wilson, E., Weber, K.S., Bridgewater, L.C. “Targeted mutation of nuclear bone morphogenetic protein 2 (nBMP2) impairs secondary immune response in a mouse model.” BioMed Research International vol. 2015, Article ID 975789, doi:10.1155/2015/975789 http://www.hindawi.com/journals/bmri/2015/975789/ (2015).
  6. Zhang, C., Yin, A., Li, H., Wang, R., Wu, G., Shen, J., Zhang, M., Wang, L., Hou, Y., Ouyang, H., Zhang, Y., Zheng, Y., Wang, J., Lv, X., Wang, Y., Zhang, F., Zeng, B., Li, W., Yan, F., Zhao, Y., Pang, X., Zhang, X., Fu, H., Chen, F., Zhao, N., Hamaker, B.R., Bridgewater, L.C., Weinkove, D., Clement, K., Dore, J., Holmes, E., Xiao, H., Zhao, G., Yang, S., Bork, P., Nicholson, J.K., Wei, H., Tang, H., Zhang, X., Zhao, L. “Dietary modulation of gut microbiota contributes to alleviation of both genetic and simple obesity in children.” EBioMedicine 2:966-­‐982. http://dx.doi.org/10.1016/j.ebiom.2015.07.007 (2015).
  7. Stolworthy, D.K., Bowden, A.E., Roeder, B.L., Robinson, T.F., Holland, J.G., Christensen, S.L., Beatty, A.M., Bridgewater, L.C., Eggett, D.L., Wendel, J.D., Stieger-­‐Vanegas, S. “MRI evaluation of spontaneous intervertebral disc degeneration in the alpaca cervical spine.” Journal of Orthopaedic Research http://onlinelibrary.wiley.com/doi/10.1002/jor.22968/full (2015).
  8. Xue, Z., Zhang, W., Wang, L., Hou, R., Zhang, M., Fei, L., Zhang, X., Huang, H., Bridgewater, L., Jiang, Y., Jiang, C., Zhao, L., Pang, X., and Zhang, Z. “The bamboo-­‐eating giant panda harbors a carnivore-­‐like gut microbiota, with excessive seasonal variations.” mBio 6:3, doi: 10.1128/mBio.00022-­‐15 http://mbio.asm.org/content/6/3/e00022-­‐15.full (2015).
  9. Chen, H., Liu, Y., Zhang, M., Wang, G., Qi, Z., Bridgewater, L.C., Zhao, L., Tang, Z, Pang, X. “A Filifactor alocis-­‐centered co-­‐occurrence group associates with periodontitis across different oral habitats.” Scientific Reports 5:9053, doi: 10.1038/srep09053 http://www.nature.com/articles/srep09053 (2015).
  10. Stolworthy, D.K., Fullwood, R.A., Merrell, T.M., Bridgewater, L.C., & Bowden, A.E. “Biomechanical comparison of the camelid and human intervertebral disc.” Journal of Orthopaedic Translation 3:34-­‐43, http://dx.doi.org/10.1016/j.jot.2014.12.001 (2014).
  11. Bridgewater, L.C., Mayo, J.L., Evanson, B.G., Whitt, M.E., Dean, S.A., Yates, J.D., Holden, D.N., Schmidt, A.D., Fox, C.L., Dhunghel, S., Steed, K.S., Adam, M.M., Nichols, C.A., Loganathan, S.K., Barrow, J.R., & Hancock, C.R. “A novel bone morphogenetic protein 2 mutant mouse, nBmp2NLStm, displays impaired intracellular Ca2+ handling in skeletal muscle.” BioMed Research International. Volume 2013, article ID 125492 http://dx.doi.org/10.1155/2013/125492 (2013).
  12. Ricks, M.S., Farrell, J.T., Falk, D.J., Holt, D.W., Rees, M., Carr, J., Williams, T., Nichols, B.A., Bridgewater, L.C., Reynolds, P.R., Kooyman, D.L., & Seegmiller, R.E. “Osteoarthritis in the temporomandibular joint of Col2a1 mutant mice.” Archives of Oral Biology. 58:1092-­‐1099 http://www.sciencedirect.com/science/article/pii/S0003996913000666 (2013).

Posters

  1. Bowden, A.E., Beatty, A.M., Bridgewater, L.C. “Design and validation of a complex loading whole spinal segment bioreactor.” Philadelphia Spine Research Symposium, held in conjunction with the Orthopaedic Research Society. Philadelphia, Pennsylvania (2015).
  2. Hancock, J., Cook, M., Grose, J., Bridgewater, L.C., and Weber, K.S. “Role of PAS kinase and metabolism on immune cells.” Autumn Immunology Conference. Chicago, Illinois (2015).
  3. Rees, A., Franson, J., White, J., Ong, K.L., Choksi, N., Hilton, A., Grose, J., and Bridgewater, L.C. “The role of PAS kinase and the gut microbiome in metabolism and diabetes onset in mice. American Society for Microbiology. New Orleans, Louisiana (2015).
  4. Yates, J.D. Bridgewater, L.C. “Evidence for a nuclear variant of decapentaplegic (dpp).” Southwest Regional Meeting of the Society for Developmental Biology. Aurora, Colorado (2014).
  5. Mayo, J.L., Nichols, B.A., Olsen, D.S., Cordner, R.D., Hancock, C.R., Weber, K.S., Wilson, E., Edwards, J.G., Barrow, J.R., and Bridgewater, L.C. “The nBMP2 mutant mouse shows defects in intracellular calcium transport-­‐regulated pathways.” Southwest Regional Meeting of the Society for Developmental Biology. Aurora, Colorado (2014).
  6. Bridgewater, L.C., Christensen, S.L. Stolworthy, D.K., Fullwood, R.A., Merrell, T.M., Holland J.G., Harmon, L.M., Robinson, T., Bowden, A.E. “Development of an alpaca disc culture system for the study of intervertebral disc degeneration.” Second International Spine Research Symposium, Philadelphia Spine Research Society. Philadelphia, Pennsylvania (2013).
  7. Bowden, A.E, Stolworthy, D.K., Fullwood, R.A., Merrell, T.M., Robinson, T.F., Christensen, S.L., Holland J.G., Bridgewater, L.C. “Development of an alpaca disc culture system for the study of intervertebral disc degeneration.” Orthopaedic Research Society Annual Meeting, San Antonio, Texas (2013).
  8. Stolworthy, D.K., Fullwood, R.A., Merrell, T.M., Bowden, A.E., Bridgewater, L.C. “Mechanical parallels for a camelid cervical spine model of lumbar disc degeneration.” Second International Spine Research Symposium, Philadelphia Spine Research Society. Philadelphia, Pennsylvania (2013).
  9. Fullwood, R.A., Stolworthy, D.K., Bowden, A.E., and Bridgewater, L.C. “Alpaca cervical spine anatomy: Shape, size, AF/NP ratio.” Emerging Ideas in Biomedical Research Conference, BYU, Provo, UT (2013). (1st place prize in the poster competition.)
  10. Christensen, S.L., Holland, J.G., Fullwood, R.A., Stolworthy, D.K., Bowden, A.E., Robinson, T.F., and Bridgewater, L.C. “Development of an alpaca disc culture system for the study of intervertebral disc degeneration.” Emerging Ideas in Biomedical Research Conference, BYU, Provo, UT (2013). (2nd place prize in the poster competition.)
  11. Olsen, D.S., Bailey, K.T., Nichols, B.A., and Bridgewater, L.C. “Lack of nuclear BMP-­‐2 causes reduced spleen size.” American Society for Biochemistry and Molecular Biology Annual Meeting, Boston, Massachusetts (2013).
  12. Nichols, B.A., Goar, W.A., McCune, B.T., and Bridgewater, L.C. “Nuclear localized BMP2 promotes cell cycle progression. American Society for Biochemistry and Molecular Biology Annual Meeting, Boston, Massachusetts (2013).

Summary of Spending

The budget for this project was spent as follows:

  • Animal care costs, WIDB mouse facility ($10,000)
  • PCR enzymes and primers for genotyping the mice ($2,000)
  • Injection needles, glucose test strips, insulin, glucose, and glucometer for insulin tolerance tests and glucose tolerance tests ($3,000)
  • Screw-capped test tubes for storing fecal samples and the various tissue types saved at dissection of each mouse—brain, liver, lymph nodes, skeletal muscle, kidney, fat pads, gastrointestinal tract tissue and contents ($2000)
  • Student wages ($3000)