RNA-seq Analysis of Wild-Type and Dcaf8 Knockout LT-HSCs in Mice

Hematopoietic stem cell aging leads to dysfunction of hematopoietic and immune systems, which in return contribute to organismal aging and the development of aging-related diseases. Understanding the molecular mechanisms of HSC aging is critical for developing interventions to treat and prevent aging-related diseases. Here, we show that DCAF8, a substrate receptor of E3 ubiquitin ligases, is highly expressed in HSCs and undergoes a progressive decline with age. Loss of DCAF8 in mice results in aging-like phenotype in HSCs, characterized by increased number of HSCs, decreased self-renewal capacity, cellular senescence and elevated DNA damage. Mechanistically, DCAF8 mediates the degradation of DOCK11, a guanine nucleotide exchange factor for CDC42. In the absence of DCAF8, DOCK11 accumulates, leading to elevated CDC42 activity and consequential loss of polarity of HSCs. Knocking out of Dock11 mitigates the senescence, DNA damage, and self-renewal defects of Dcaf8-/- HSCs. This study highlights a critical role of DCAF8 in regulating HSC aging via the DOCK11-CDC42 axis and suggests potential therapeutic targets for preventing the age-related decline in HSC functions. To explore the mechanisms by which Dcaf8 knockout leads to functional defects in HSCs, we performed RNA-sequencing on LT-HSCs sorted from 3 Dcaf8 knockout mice and 3 WT controls at young ages.