Genetic Stability of Human Mesenchymal Stem Cells Exposed to X-Rays or Heat Shock in Culture

Abstract

Abstract. The aim of this study was to investigate the cytogenetic assay of endometrial mesenchymal stem cells (eMSC) in vitro after the exposure to a sublethal dose of X-rays and the sublethal heat shock (HS). For the analysis of chromosomes, we used the G-banding technique. We showed that both types of stress caused similar changes in eMSC karyotype structure. In both cases, 80% of the cell population had karyotype abnormalities. The main types of rearrangements were aneuploidy and chromosomal breaks. Chromosomes 1 and 4 were involved in breaks more often than other chromosomes. The number of chromosomes involved in the restructuring as a result of HS was larger than after X-rays.

Long-Term Cryopreservation May Cause Genomic Instability and the Premature Senescence of Cells

“…Thus, it can be assumed that the telomere damage (and other accumulated defects in the genome) of the eMSCs, which we have found by karyotyping after the long-term cryo-freezing of cells, is the path to their premature senescence. Interestingly, in thawed cells, we observed the karyotypic changes similar to those which we had found previously in the same eMSC line when the cells were subjected to X-ray irradiation or heat shock [26]. Therefore, it suggests that long-term cryopreservation can be considered as a severe stress factor for these cells.…”

Chromothripsis—Explosion in Genetic Science

“…In chromoanasynthesis, as a result of absent DNA replication, a part of the chromosome (fragments 1-12) undergoes complex rearrangements. In the rearranged chromosome, in addition to changing the sequence of the chromosome region (fragments 7, 2, 6, 5, 4), amplified regions are observed (fragments 8,3,9), and some of the fragments are removed (fragments 1,10,11,12). The main difference between chromoanasynthesis and chromothripsis as well as chromoplexy is the presence of both losses and gains (duplications/triplications) region on the rearranged chromosome.…”

“…Tumor cell transformation is usually accompanied by numerical (monosomies, trisomies, tetrasomies, etc.) and structural chromosomal alterations, including: chromatid breaks, ring chromosomes, additional material of unknown origin, derivatives chromosomes, balanced translocations, deletions, inversions and non-condensed whole chromosomes, or chromosomes with impaired heterochromatin condensation, among others [ 1 , 2 , 3 , 4 , 5 , 6 ]. In the cancer cell genomes detected, the multiple chromosomal changes are the result of a stepwise process in which mutations accumulate over time [ 7 ].…”

“…Since 2013, the International System for Human Cytogenetic Nomenclature has defined chromothripsis as complex patterns of alternating changes in the number of gene copies (normal, increased, or with loss) along a chromosome or chromosomal segment [18]. During chromothripsis, the chromosome or the chromosome arm was destroyed, followed by incomplete and accidental restoration of fragments (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). When the chromosome is restored, the orientation of the fragments can change (fragments 7, 10), some of the fragments are removed (fragments 2, 5, 9, 11, 12), and some form extrachromosomal double minutes (fragments 4).…”