RESUMO
INTRODUCTION: Aging of hematopoietic stem cells (HSCs) has emerged as an important challenge to human health. Recent advances have raised the prospect of rejuvenating aging HSCs via specific medical interventions, including pharmacological treatments. Nonetheless, efforts to develop such drugs are still in infancy until now. OBJECTIVES: We aimed to screen the prospective agents that can rejuvenate aging HSCs and explore the potential mechanisms. METHODS: We screened a set of natural anti-aging compounds through oral administration to sub-lethally irradiated mice, and identified 2,3,5,4'-tetrahydroxystilbene-2-O-ß-D-glucoside (TSG) as a potent rejuvenating agent for aging HSCs. Then naturally aged mice were used for the follow-up assessment to determine the HSC rejuvenating potential of TSG. Finally, based on the transcriptome and DNA methylation analysis, we validated the role of the AMP-activated protein kinase (AMPK)-ten-eleven-translocation 2 (Tet2) axis (the AMPK-Tet2 axis) as the underlying mechanisms of TSG for ameliorating HSCs aging. RESULTS: TSG treatment not only significantly increased the absolute number of common lymphoid progenitors (CLPs) along with B lymphocytes, but also boosted the HSCs/CLPs repopulation potential of aging mice. Further elaborated mechanism research demonstrated that TSG supplementation restored the stemness of aging HSCs, as well as promoted an epigenetic reprograming that was associated with an improved regenerative capacity and an increased rate of lymphopoiesis. Such effects were diminished when the mice were co-treated with an AMPK inhibitor, or when it was performed in Tet2 knockout mice as well as senescent cells assay. CONCLUSION: TSG is effective in rejuvenating aging HSCs by modulating the AMPK- Tet2 axis and thus represents a potential candidate for developing effective HSC rejuvenating therapies.
RESUMO
The AGL6 (AGMOUSE LIKE 6) gene is a member of the SEP subfamily and functions as an E-class floral homeotic gene in the development of floral organs. In this study, we cloned IiAGL6, the orthologous gene of AGL6 in Isatis indigotica. The constitutive expression of IiAGL6 in Arabidopsis thaliana resulted in a late-flowering phenotype and the development of curly leaves during the vegetative growth period. Abnormal changes in floral organ development were observed during the reproductive stage. In woad plants, suppression of IiAGL6 using TRV-VIGS (tobacco rattle virus-mediated virus-induced gene silencing) decreased the number of stamens and led to the formation of aberrant anthers. Similar changes in stamen development were also observed in miRNA-AGL6 transgenic Arabidopsis plants. Yeast two-hybrid and BiFC tests showed that IiAGL6 can interact with other MADS-box proteins in woad; thus, playing a key role in defining the identities of floral organs, particularly during stamen formation. These findings might provide novel insights and help investigate the biological roles of MADS transcription factors in I. indigotica.
