Zabirnyk A. The role of the lamin protein in adipose-derived stromal cells functioning

Dissertation is devoted to the study of influence regularities of point mutations G232E, R471C, R482L, R527C and G465D in the LMNA gene on human adipose derived stem cells (ADSC) clonogenic properties, the degree of their adipogenic differentiation and expression levels of markers of adipogenic differentiation(MAD). The activity of histone deacetylases, adipo-associated genes expression in cultured ADSC carrying mutant genes, as well as the conformation of the mutant lamins sites and their interaction energy with the partner proteins SREBP1 and EMD was also measured. It is shown that all the investigated mutations in lamin A/C reduced ADSC clonogenicity. The level of ADSC adipogenic differentiation also increases under the influence of mutations in LMNA gene, which is explained by a shift of a multipotent cells pool to a more committed state. All of the studied mutations generally increased expression levels of MAD such as PPARG, SREBF1 and CFD, while the increase was different for different stages of the adipogenic differentiation. In addition, 28adipo-associated genes with significant changes in expression were identified. They formed a unique expression profiles for each mutation. However, they had a similar expression for mutations associated with one of the considered pathophenotypic laminopathies syndromes. It was showed by means of modeling of mutant lamins and simulation of their interaction with SREBP1 and EMD that there was a significant change in the affinity of the investigated mutant lamin to their proteins partners. The increase of histone deacetylase activity in cultures ADSC carrying mutant genes was also demonstrated. This indicates an overall decrease in the number of active genes. The obtained results allow us to propose a novel hypothesis regarding one of the possible mechanisms for the laminopathies pathogenesis formation. Namely, LMNA genes mutations by disrupting the processes of self-renewal and differentiation of MSCs reduce the pool of multipotent stem cells and thereby accelerate their age-dependent depletion depot in the human body. With age, when the threshold value for pool of the stem cells is reached and their differentiation is reduced, the severe pathogenesis of laminopathies develops