Stem cell and skeletal muscle aging.

(NIA, 1R01 AG068250-1, R56 AG065561-01)

Stelios T. Andreadis Lab

Introduction & Significance

Zoom image: Fig 1: Reversing aging hallmarks in skeletal muscle in vitro and in vivo. From Sci Adv . 2.1.

Fig 1: Reversing aging hallmarks in skeletal muscle in vitro and in vivo. From Sci Adv .

The Stelios Andreadis research group has discovered that introduction of a single pluripotency gene, Nanog reversed the effects of cellular senescence and restored the ability of MSCs to generate contractile force.

Organismal aging can be broadly defined as the progressive decline of the proper functions of the body leading to organismal deterioration and eventually death. Although current understanding of aging is limited, advances in medicine and the modern lifestyle achieved a dramatic increase in life expectancy from ~30 years in the pre-modern era to ~70-80 years in the present day1 Unfortunately, this increase also coincides with the emergence of age-related diseases that have significant impact on the quality of life and the economies of modern societies. Donor age and replicative senescence have significant effects on gene expression profile and function of stem cells in multiple tissues including smooth and skeletal muscle.

Zoom image: Fig 2(A) Lentiviral reporters that were developed in my lab are used in combination with CRISPR libraries to discover genes associated with aging or reversal of aging hallmarks. 2.1A.

Fig 2(A) Lentiviral reporters that were developed in my lab are used in combination with CRISPR libraries to discover genes associated with aging or reversal of aging hallmarks.

Zoom image: Fig2(B):  Genome wide metabolic model that uses transcriptomic and metabolomic data to predict metabolic fluxes and pathways at work in senescence. In collaboration with Dr. Rudi Gunawan (UB CBE).  2.2B.

Fig2(B):  Genome wide metabolic model that uses transcriptomic and metabolomic data to predict metabolic fluxes and pathways at work in senescence. In collaboration with Dr. Rudi Gunawan (UB CBE). 

Research Findings

Early work from the lab showed that not only mesenchymal stem cell (MSCs) from adult animals lost their proliferation and clonogenic potential but they also exhibited diminished contractile force generation when they were coaxed to differentiate towards smooth muscle cells (SMC) 2. Notably, the lab discovered that introduction of a single pluripotency gene, Nanog reversed the effects of cellular senescence and restored the ability of MSCs to generate contractile force. To elicit its effects, NANOG enabled reactivation of the ROCK and Transforming Growth Factor (TGF)-beta pathways-both of which were impaired in senescent cells-leading to ACTIN polymerization, MRTF-A translocation into the nucleus and serum response factor (SRF)-dependent myogenic gene expression 3-5. The lab also reported that the significant loss of Col3 and elastin that occurs with aging could be reversed by ectopic expression of NANOG, mostly via restoring the TGFb1 pathway 6. Given the importance of Col3 and elastin in biomechanics (elasticity) of tissues such as skin and arteries, our result is of importance in regenerating the declining function of aged tissues.

Recent work in the Andreadis lab implicated cellular metabolism in senescence as well as NANOG-mediated rejuvenation of MSC and skeletal muscle myoblasts 7. Specifically, in a paper in Science Advances we showed that NANOG ameliorated many of the hallmarks of cellular senescence including autophagy, energy homeostasis, genomic stability, nuclear integrity and mitochondrial function (Fig. 1). Most notably, NANOG increased the number of muscle stem cells (Pax7+) in the muscle of prematurely aging mice. This demonstrated the feasibility of reversing cellular aging in the body without the need to reprogram cells to an embryonic pluripotent state, a process that is often used in stem cell therapy but runs the risk of tumorigenesis.

Most recently, the lab discovered that senescent cells reprogram their metabolism from glycolysis to amino acid catabolism to fuel their bioenergetic demands. NANOG reprogramming reverses many of the aging hallmarks in part by metabolic rewiring to glycolysis and oxidative phosphorylation both in vitro and in vivo. Specifically, NANOG decreased expression of MAT2A (the first enzyme in the methionine pathway) and ammonium levels, restored glycolysis, the regeneration capacity after CTX injury and the force generating ability of aged muscle in progeria mice. These results are highly significant because they demonstrate that small, “druggable” molecules affecting metabolism can reverse the function of aged tissues in vivo. These results were recently published in Nat Comms and Cell Reports 8-9.

Future Work

Current and future work in the Andreadis lab focuses on understanding how NANOG affects metabolism and epigenetics in multiple projects:

  • Development of a novel animal model including a fast-aging mouse model that can express NANOG in skeletal muscle upon doxycycline administration;
  • Development of tissue engineered models of aged skeletal muscle that can serve as drug testing beds;
  • Use of genome-wide CRISPR libraries in combination with lentiviral reporter arrays developed in my lab to discover genes that induce or accelerate senescence as well as reversal of senescence hallmarks (Fig. 2A);
  • Mathematical models that use transcriptomic and metabolomic data to predict metabolic pathway rewiring in aging and rejuvenation (Fig. 2B). 

Students of the Project

Post-doc: Izuagie Ikhapoh, Ph.D.

Graduate students: Nika Rajabian; Shahryar Shahini; Pihu Mehrotra; Debanik Choudhury, Sai Harsha Bhamidipati (CBE), Hamsa Vardini Senthil Kumar (GGB), Artem Nikolaev (BME)

Collaborators: Kirk Personius (School of Public Health and Heatlh Professions); Bruce Troen and Kenneth Seldeen (UB Medicine); Rudi Gunawan (CBE); Aimee Stablewski (Roswell Park Comprehensive Cancer Center)

References

  1. Roser, M. Life Expectancy. OurWorldInData.org. (2015).
  2.  Han, J., Liu, J.Y., Swartz, D.D. & Andreadis, S.T. Molecular and functional effects of organismal ageing on smooth muscle cells derived from bone marrow mesenchymal stem cells. Cardiovasc Res 87, 147-155 (2010).
  3. Mistriotis, P., Bajpai, V.K., Wang, X., Rong, N., Shahini, A., Asmani, M., Liang, M.S., Wang, J., Lei, P., Liu, S., Zhao, R. & Andreadis, S.T. NANOG Reverses the Myogenic Differentiation Potential of Senescent Stem Cells by Restoring ACTIN Filamentous Organization and SRF-Dependent Gene Expression. Stem cells 35, 207-221 (2017).
  4.  Shahini, A., Mistriotis, P., Asmani, M., Zhao, R. & Andreadis, S.T. NANOG Restores Contractility of Mesenchymal Stem Cell-Based Senescent Microtissues. Tissue Eng Part A 23, 535-545 (2017).
  5.  Han, J., Mistriotis, P., Lei, P., Wang, D., Liu, S. & Andreadis, S.T. Nanog reverses the effects of organismal aging on mesenchymal stem cell proliferation and myogenic differentiation potential. Stem cells 30, 2746-2759 (2012).
  6.  Rong, N., Mistriotis, P., Wang, X., Tseropoulos, G., Rajabian, N., Zhang, Y., Wang, J., Liu, S. & Andreadis, S.T. Restoring extracellular matrix synthesis in senescent stem cells. FASEB J 33, 10954-10965 (2019).
  7. Rajabian, N., Shahini, A., Asmani, M., Vydiam, K., Choudhury, D., Nguyen, T., Ikhapoh, I., Zhao, R., Lei, P. & Andreadis, S.T. Bioengineered Skeletal Muscle as a Model of Muscle Aging and Regeneration. Tissue Eng Part A 27, 74-86 (2021).
  8.  Choudhury, D., Rong, N., Ikhapoh, I., Rajabian, N., Tseropoulos, G., Wu, Y., Mehrotra, P., Thiyagarajan, R., Shahini, A., Seldeen, K.L., Troen, B.R., Lei, P. & Andreadis, S.T. Inhibition of glutaminolysis restores mitochondrial function in senescent stem cells. Cell reports 41, 111744 (2022).
  9.  Rajabian, N., Ikhapoh, I., Shahini, S., Choudhury, D., Thiyagarajan, R., Shahini, A., Kulczyk, J., Breed, K., Saha, S., Mohamed, A.M., Udin, S.B., Stablewski, A., Seldeen, K., Troen, B.R., Personius, K. & Andreadis, S.T. Methionine adenosyltransferase2A inhibition decreases insulin resistance and restores the strength of aged skeletal muscle. Nat Comms Accepted (2022).