Lars Gustaf Larsson
Research
CONTRIBUTIONS TO SCIENCE
Sarcopenia: For more than four decades, my research group has studied the effects of aging on skeletal muscle function and size (sarcopenia) in humans and in experimental models. Specific interest has been focused on regulation of contraction at the muscle, motor unit, muscle fiber and motor protein levels and how muscle function is influenced by contractile protein isoform expression and post-translational modifications. In order to achieve these goal, we have modified or developed research methods to study skeletal muscle from both humans and rodents, such as: 1. Improving the glycogen-depletion technique to visualize and identify motor unit fibers, their spatial organization and myofibrillar protein isoform expression. 2. Introducing the skinned fiber preparation for the study of regulation of human muscle fibers in relation to myofibrillar protein isoform expression and the development of a cryo-protection procedure allowing long-term storage of membrane permeabilized muscle fiber bundles without affecting regulation of muscle contraction (longest observation period to date exceeds 10 years of storage at -160 0C). 3. Development of a single muscle fiber in vitro motility assay where myosin is extracted from a 1 mm long muscle fiber segment allowing detailed studies of the function of specific myosin isoforms (catalytic properties or motility speed as well as force generation capacity) without interference from structural or regulatory proteins. 4. A method to determine the 3D organization of individual myonuclei along the length of individual muscle fibers and calculating the cytoplasmic volume supported by each myonucleus by using confocal imaging, 3D reconstructions and a novel algorithm.
1. Larsson, L., Ansved, T., Edström, L., Gorza, L. Schiaffino, S. 1991. Effects of age on physiological, immunocytochemical and biochemical properties of fast-twitch single motor units in the rat. Journal of Physiology 443:257-275
2. Larsson, L., Li, X., Frontera, W.R. 1997. Effects of ageing on shortening velocity and myosin isoform composition in single fibres from man. American Journal of Physiology (Cell Physiology) 272 (Cell Physiol. 41): C638-C649
3. Höök, P., Vidyasagar, S., Larsson, L. 2001. Effects of aging on actin sliding speed on myosin from single mouse, rat and human skeletal muscle cells. American Journal of Physiology:Cell 280: C782-C788.
4. Li, M., Ogilvie, H , Ochala, J., . Konstantin, A, Iwamoto, H., Yagi, N., Bergquist, J, Larsson, L 2015. Aberrant post-translational modifications compromise human myosin motor function in old age. Aging Cell, 14, 228-235.
5. Larsson, L., Degens, H., Li, M., Salviati, L., Lee, Y. il., Thompson, W.,. Kirkland, J.L., Sandri, M. 2018. Sarcopenia; Aging-related loss of muscle mass and function. Physiological Reviews (Invited review), in press
CIM After diagnosing the first intensive care unit (ICU) patient in Scandinavia with critical illness myopathy (CIM) while being on call Christmas 1995, the research focusing on improving our understanding of basic underlying mechanisms, improving diagnosis and monitoring, implementing and evaluating intervention strategies of CIM in experimental models, and translating promising interventions to the clinic has become the dominating research in my group. This work has involved the modification of a very powerful and unique rat experimental model, originally developed by Dr. B. Dworkin at Rockefeller, to make it minimally invasive and suitable for the study of skeletal muscle. This model is not limited by early mortality and I have collaborated with Dr. Dworkin using this model for two decades, originally at the Pennsylvania State University, later at Uppsala University and currently at Karolinska Institutet. After his retirement from Penn State, Dr. Dworkin joined my research group in Sweden and we now have the only two models of this experimental set-up available worldwide allowing us to conduct two long-term studies in parallel. The hallmark of CIM is the preferential loss of the motor protein myosin, but we have also shown that the ICU condition induces significant post-translational modifications of myosin with a strong negative impact on myosin function. The current collaboration with Professor J.L. Kirkland since more than two years has been supported by a seed grant from the Mayo-Karolinska Foundation. The focus of this collaboration has been on the two factors which most strongly predict mortality and morbidity in ICU patients, i.e., old age and muscle wasting, with the aim of introducing novel pharmacological interventions targeting these two triggering factors.
1. Larsson, L., Li, X., Edström, L., Eriksson, L.I., Zackrisson, H., Argentini, C., Schiaffino, S. 2000. Loss of muscle myosin and acute quadriplegia in patients treated with non-depolarizing neuromuscular blocking agents and corticosteroids. Underlying cellular and molecular mechanisms. Critical Care Medicine 28:34-45.
2. Renaud,G., Llano-Diez, M., Ravar, B, Gorza, L., Feng HZ, Jin, J.P., Cacciani N, Gustafson, A-M., Ochala, J, Corpeno R, Li, M., Hedström, Y., Ford, G. C. , Nair, K. S. , Larsson L. 2013. Sparing of muscle mass and function by passive loading in an experimental intensive care unit model J Physiol. 591(Pt 5):1385-402
Corpeno Kalamgi, R. Salah, H., Gastaldello, S., Martinez-Redondo, V., Ruas, J., Fury, W., Bai, Y., Gromada, J., Sartori, R., Guttridge,, D.C., Sandri, M., Larsson, l. 2016. Mechano Signaling Pathways in an Experimental Intensive Care Unit Model. J Physiol Aug 1;594(15):4371-88
Salah, H., Li, M., Cacciani, N, Gastaldello, S.,Ogilvie, H, Akkad, H., Venkant Namaduri, A., Morbidino, V., Artemenko, K., Balogh, G., Martinez-Redondo, V., Hedström, Y., Dworkin, B., Bergquist, J., Ruas, J., Vigh, L., Salviati, L. Larsson, L. 2016. The chaperone co-inducer BGP-15 alleviates ventilation induced diaphragm dysfunction Science Translational Medicine. Aug 3;8(350):350ra103. doi: 10.1126/scitranslmed.aaf7099
Friedrich, O., Reid, MB, van den Berghe, G., Vanhorebeek, IO., Hermans, G
Rich, MM, Larsson, L. 2015.The Sick and the Weak: Critical Illness Neuro-/Myopathies – Cellular Mechanisms of a new acquired Channel-Coupling-Proteopathy. Physiological Reviews (Invited review) Jul;95(3):1025-1109
Adaptability The effects of chronic overuse, unloading and thyroid hormone exposure on regulation of muscle contraction and myofibrillar protein isoform expression have been investigated at the muscle cell and motor protein levels. Our understanding of regulation of muscle contraction is based on observations in amphibians and small mammals, but there are significant species-differences related to body size. The applicant has therefore investigated the impact of body size on regulation of muscle contraction at the cell and motor protein levels and myonuclear organization in mammalian species with a 100,000-fold range in body mass (ranging from the mouse to the rhinoceros and including humans) with the aim of improving our understanding of human muscle function.
1. Larsson, L., Li, X., Tollbäck, A., Grimby, L. 1995. Contractile properties in single muscle fibres from chronically overused motor units in relation to motoneuron firing properties in prior polio patients. Journal of the Neurological Sciences 132:182-192.
2. Liu, J.-X., Höglund, A.-S., Karlsson, P., Lindblad, J, Qaisar, R., Aare, S., Bengtsson, E. Larsson, L. 2009. Myonuclear domain size and myosin isoform expression in muscle fibers from mammals representing a 100,000-fold difference in body size. Experimental Physiology: 94.1:117-129.
3. Llano-Diez, M., Renaud,G., Andersson, Gonzales, H., M., Hedström, Y., Corpeno, R., Engqvist, H., Bergquist, J., Larsson L. 2012. Passive mechanical loading improves muscle function but not mass in immobilized intensive care unit patients. Critical Care 16:R209 doi:10.1186/cc11841 Highly Accessed BMC Journal publication
4. Qaisar R, Renaud G , Morine K, Barton E, Sweeney H.L, Larsson L 2012. Is functional hypertrophy and specific force related to addition of myonuclei in single muscle fibers? FASEB J 26(3):1077-85
Marx, JO, Olsson, MC, Larsson, L.2006. Scaling of skeletal muscle shortening velocity in mammals representing a 100,000-fold difference in body size. Pflügers Archives, European Journal of Physiology. 462:222-230
Methods. In order to understand the mechanisms underlying the impaired function in patients with different underlying conditions affecting muscle functions, such as myosinopathies, sarcopenia, critical illness myopathy, and neuropathies, different methods have been developed/modified to study regulation of muscle contraction in detailed under controlled conditions in the small muscle fiber segments obtained from percutaneous muscle biopsies in humans or from rodent muscles.
1. Larsson, L., Moss, R.L. 1993. Maximal velocity of shortening in relation to myosin isoform composition in single fibres from human skeletal muscles. Journal of Physiology 472:595-614.
2. Frontera, W.R, Larsson, L. 1997. A methodological study on three different techniques for membranepermeabilization of human single muscle cells obtained by percutaneous biopsy. Muscle & Nerve 20:948-952
3. Höök, P., Larsson, L. 2000. Actomyosin interactions in a novel single muscle fiber in vitro motility assay. Journal of Muscle Research and Cell Motility 21:357-365.
4. Li, M., Larsson, L. 2010. Force-generating capacity of human myosin isoforms extracted from single muscle fibre segments. J Physiol (Lond) 588:5105-14
5. Cristea, A., Karlsson Edlund, P., Lindblad, J., Qaisar, R., Bengtsson, E., Larsson, L. 2010. Effects of ageing and gender on the spatial organization of myonuclei in single human skeletal muscle cells. Aging Cell 9:685-697.
Experimental models In order to unravel basic mechanisms underlying pathophysiological changes associated with aging, critical illness myopathy and hereditary myopathies affecting contractile proteins a significant effort has be devoted to the development/modification of different experimental models, such as 1) the glycogen depletion method where improvements have been made in the experimental set-up, the technique for enhancing glycogen depletion, quantitative methods for measuring enzyme activities in individual motor unit fibers, introduction of immunohistochemistry to identify myosin heavy chain isoforms and a computerized model to determine the spatial organization of motor unit fibers, 2) an experimental porcine ICU model where animals were exposed to different triggering factors for 5 days, and 3) an experimental rat ICU model not limited by early mortality and the longest duration a rat has been monitored in this model to date is 96 days. In time-resolved analyses, detailed analyses of gene/protein expression, protein modifications and regulation of muscle contraction have been investigated at durations varying from 6h to 14 days. Conventional rat ICU models cannot maintain life support for longer than a day or two adding a significant confounding factor, i.e. a deteriorating preparation.
1. Larsson, L., Edström, L., Lindegren, B., Gorza, L, Schiaffino, S. 1991. MHC composition and enzyme-histochemical and physiological properties of a novel fast-twitch motor unit type. American Journal of Physiology (Cell Physiology) 261:C93-C101.
2. Larsson, L. 2007. Experimental animal models of muscle wasting in intensive care unit patients. Critical Care Medicine 35(9 Suppl):S484-7
3. Ochala, J., Gustafson, A.-M., Li, M., Aare, S., Qaisar, R., Llano Diez, M., Banduseela, V., Hedström, Y, Tang, X, Dworkin, B, Nair, S, Ford, C., Perera, S., Gautel, M., Larsson. L. 2011. Preferential skeletal muscle myosin loss in response to mechanical silecing in a novel rat intensive care unit model: underlying mechanisms. J Physiol (Lond) 589 (8): 2007-2026.
4. Akkad, H., Corpeno, R., Larsson, L. 2014. Masseter Muscle Myofibrillar Protein Synthesis and Degradation in an Experimental Critical Illness Myopathy Model. Plos-One Vol 9, Issue 4, e92622
MENTORING
PhD
1. Tor Ansved (Dr. Med. Sci, 1990, KI)
2. Xiaopeng Li (Dr. Med. Sci, 1996, KI)
3. Fushun Yu (Dr. Med. Sci, 1999, KI)
4. Peter Höök, (Dr. Med. Sci, 2001, KI)
5. Lennart Gransberg (Dr. med sci, 2001, KI)
6. James Marx (PhD, 2001, the Pennsylvania State University)
7. Bhagavathi Ramamurthy (PhD, 2002, the Pennsylvania State University)
8. Holly Norman (Dr. Med. Sci, 2006, Uppsala University)
9. Alexander Cristea (Dr. med sci, 2008, Uppsala University)
10. Mingxin Li (Dr. med sci, 2010, Uppsala University)
11. Rizwan Qaisar (Dr. med sci, 2012, Uppsala University)
12. Monica Llano Diez (Dr. med sci, 2012, Uppsala University)
13. Sudhakar Aare (Dr. med sci, 2012, Uppsala University)
14. Varuna Banduseela (Dr. med sci, 2012, Uppsala University)
15. Guillaume Renaud (Dr. med sci, 2013, Uppsala University)
16. Johan Lindqvist (Dr. Med. Sci., Uppsala Univeristy)
17. Rebeca Corpeno (Dr. Med sci, 2015, Karolinska Institutet)
18. Hannah Ogilvie (Dr. Med sci, 2015, Karolinska Institutet)
19. Heba Salah (Dr. Med. Sci. 2017, Uppsala University/ Karolinska Institutet)
20. Hazem Akkad (Dr. Med. Sci, 2018 Karolinska Institutet)
MS
1. Andrew Kerman (MS, 2000, the Pennsylvania State University)
2. David van Dyke (MS, 2001, the Pennsylvania State University)
3. Raghu Kolluri (MS, 2001, the Pennsylvania State University)
4. Marcus Glover (MS, 2002, the Pennsylvania State University)
Post-doctoral student
1. Hakan Gur, Professor, MD, 1.5 years between 1984-1990
2. Walter Frontera, MD, PhD, 1995-1996
3. Hans Degens, PhD, 1996-1997
4. Vidyasagar Sriramoju, MD, 1999
5. Håkan Zackrisson, MD, 2002
6. James Marx,. PhD, DVM, 2001-2002
7. Fushun Yu, PhD, MD, 2001-2002
8. Arimantas Lionikas, PhD, 2001-2003
9. Jenny Nordqvist, PhD, 2002-2005
10. Lottie Olsson, PhD, 2003-2005
11. Stina Höglund, Ph.D., Docent, 2005, Uppsala University
12. Julien Ochala, PhD, Docent, 2005-2013
13. Meishan Li, MD, PhD, 2005-present
14. Nicola Cacciani, MD, PhD, 2009-present
15. Stefano Gastadello, PhD (2013-2017)
16. Monica Llano Diez , PhD (2017- present)