Session Title: Biology and Pathology of Bone and Joint
Session Type: Abstract Submissions (ACR)
Background/Purpose: Previous work by our group and others indicated that an accumulation of lamin A (LMNA) was associated with the osteoarthritis (OA) chondrocyte phenotype. Mutations of this protein are linked to laminopathies and specifically to Hutchinson-Guilford Progeria Syndrome (HGPS), an accelerated aging disease. Some authors have proposed that a deregulation of LMNA affects the differentiation potential of stem cells. In the present study, we examined the effect of the over-expression of LMNA, or its mutant form progerin (PG), on the mesoderm differentiation potential of MSCs.
Methods: Mesenchymal stem cells (MSCs) from human umbilical cord (UC) stroma have previously been isolated, expanded and differentiated towards mesoderm cell lineages. For efficient gene delivery of wt LMNA, PG and GFP (Green Fluorescence Protein), we used a lentiviral expression system. GFP-transduced MSCs were used as control for the differentiation study since they present a differentiation capacity similar to that of untransduced MSCs. Osteogenic potential was studied by with alizarin red staining to assess calcium deposits as well as Real-Time PCR of ALP, OC and Runx2 to assess early and late osteogenic differentiation. Adipogenic potential was studied with Oil Red staining for lipid droplets and Real-Time PCR of LPL, FABP and ADIPOQ, for early and late adipogenic differentiation. Chondrogenesis and hypertrophy were studied using immunohistochemestry and Real-Time PCR of Aggrecan, MMP-13, Type II Collagen, Type I Collagen and Type I Collagen.
Results: We found that over-expression of LMNA or PG by lentiviral gene delivery leads to defects in differentiation potential. PG-transduced MSCs present defects in adipogenic and osteogenic potential, The chondrogenic potential is defective in PG-MSCs, which present a decrease in COL2 and Aggrecan as revealed by both immunohistochemystry and Real-Time PCR. LMNA and PG-transduced MSCs have an increase in hypertrophy markers (MMP-13 and Type X Collagen) during chondrogenic differentiation, as well as a decrease in manganese superoxide dismutase (MnSODM) and an increase of mitochondrial MnSODM-dependent reactive oxygen species (ROS). ROS synthesis was partially (51%) and totally reverted by N-Acetyl Cystein, ROS scavenger, (NAC) at 20 and 40 µg/mL respectively for 1 hour in culture. In addition, defects in chondrogenesis detected by immunohistochemestry and Real Time-PCR are partially reversed by incubations with NAC at 40 µg/mL for 1 hour.
Conclusion: Our results suggest that OA process could be enhanced by defects in stem cell differentiation, partially due to imbalance in oxidative stress.
A. De La Fuente,
I. A. Lesende-Rodriguez,
M. C. Arufe,
F. J. Blanco,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/lamin-a-deregulation-in-human-mesenchymal-stem-cells-promotes-an-impairment-in-their-chondrogenic-potential-and-imbalance-in-their-response-to-oxidative-stress/