Vicente, A. | Search bioRxiv

bioRxiv2018

Exploring tRNA gene cluster in archaea

Shared traits between prokaryotes and eukaryotes are helpful in the understanding of the tree of life evolution. In bacteria and eukaryotes, it has been shown a particular organization of tRNA genes as clusters, but this trait has not been explored in archaea domain. Here, based on analyses of complete and draft archaeal genomes, we demonstrated the prevalence of tRNA gene clusters in archaea. tRNA gene cluster was identified at least in three Archaea class, Halobacteria, Methanobacteria and Methanomicrobia from Euryarchaeota supergroup. Genomic analyses also revealed evidence of tRNA gene cluster associated with mobile genetic elements and horizontal gene transfer inter/intra-domain. The presence of tRNA gene clusters in the three domain of life suggests a role of this type of tRNA gene organization in the biology of the living organisms.

genomics↗

bioRxiv2017

Overexpression Of Hypoxia-Inducible Factor 1 Alpha Improves Immunomodulation By Dental Mesenchymal Stem Cells

BackgroundHuman dental mesenchymal stem cells (MSCs) are considered as highly accessible and attractive MSCs for use in regenerative medicine, yet some of their features are not as well characterized as in other MSCs. Hypoxia-preconditioning and hypoxia inducible factor 1 alpha (HIF-1 alpha) overexpression significantly improve MSC therapeutics, but the mechanisms involved are not fully understood. In the present study, we characterize immunomodulatory properties of dental MSCs and determine changes in their ability to modulate adaptive and innate immune populations after HIF-1 alpha overexpression.\n\nMethodsHuman dental MSCs were stably transduced with GFP (MSCs) or GFP-HIF-1 alpha lentivirus vectors (HIF-MSCs). Hypoxic-like metabolic profile was confirmed by mitochondrial and glycolysis stress test. Capacity of HIF-MSCs to modulate T cell activation, dendritic cell differentiation, monocyte migration and polarizations towards macrophages and NK cell lytic activity was assessed by a number of functional assays in co-cultures. Expression of relevant factors were determined by PCR analysis and ELISA.\n\nResultsWhile HIF-1 alpha overexpression did not modify inhibition of T cell activation by MSCs, HIF-MSCs impaired dendritic cell differentiation more efficiently. HIF-MSCs induced also higher attraction of monocytes, which differentiate into suppressor macrophages, and exhibited enhanced resistance to NK cell-mediated lysis, which support the improved therapeutic capacity of HIF-MSCs. HIF-MSCs also displayed a pro-angiogenic profile characterized by increased expression of CXCL12/SDF1 and CCL5/RANTES and complete loss of CXCL10/IP10 transcription.\n\nConclusionsImmunomodulation and expression of trophic factors by dental MSCs make them perfect candidates for cell therapy. Overexpression of HIF-1 alpha enhances these features and increases their resistance to allogenic NK cell lysis and, hence, their potential in vivo lifespan. Our results further support the use of HIF-1 alpha-expressing dental MSCs for cell therapy in tissue injury and immune disorders.

immunology↗