º£½ÇÆƽâ°æ

PurposeNuclear factor erythroid 2-related factor 2 (Nrf2) is a crucial cytoprotective protein that shields cells from electrophilic and oxidative stress. Mice lacking Nrf2 exhibit heightened susceptibility to myelosuppression due to impaired hematopoietic reconstitution. In this study, we examined the altered sensitivity to ionizing radiation (IR) and 7,12-dimethylbenz(a)anthracene (DMBA) in Nrf2?/? mice separately.Materials and MethodsIrradiate Nrf2?/? or wild-type mice with a dose of 4?Gy to observe changes in body weight, survival rate, and blood routine at 12 months. DMBA was used to treat Nrf2?/? and wild-type mice, and the body weight and survival rate of the mice were measured. The changes of heme oxygenase-1(HO1) and NAD(P)H: quinone oxidoreductase 1(NQO1) in mice treated with IR or DMBA were detected by RT-qPCR and western blotting.ResultsOur results indicate that Nrf2 deficiency leads to more severe blood and immune system injury in mice exposed to IR or DMBA. Additionally, long-term monitoring revealed that Nrf2 deletion resulted in more severe myelosuppression, leukemia-like symptoms, and higher cancer rates. At the mRNA and protein levels, there was no significant increase in HO1 and NQO1 levels in the Nrf2?/? mice treated with IR or DMBA. These adverse effects might be attributed to the inhibited protein levels of HO1 and NQO1 and significant DNA damage in hematopoietic stem and progenitor cells (HSPCs).ConclusionsWe demonstrate that the genetic deficiency of Nrf2 in mice leads to reduced antioxidant capacity and suppression of hematopoietic and immune system function, resulting in increased sensitivity to IR or DMBA. Graphical Abstract

Reduced quantity and quality of stem cells in aged individuals hinders cardiac repair and regeneration after injury. We used young bone marrow (BM) stem cell antigen 1 (Sca-1) cells to reconstitute aged BM and rejuvenate the aged heart, and examined the underlying molecular mechanisms. BM Sca-1+ or Sca-1- cells from young (2-3 months) or aged (18-19 months) GFP transgenic mice were transplanted into lethally irradiated aged mice to generate 4 groups of chimeras: young Sca-1+ , young Sca-1- , old Sca-1+ , and old Sca-1- . Four months later, expression of rejuvenation-related genes (Bmi1, Cbx8, PNUTS, Sirt1, Sirt2, Sirt6) and proteins (CDK2, CDK4) was increased along with telomerase activity and telomerase-related protein (DNA-PKcs, TRF-2) expression, whereas expression of senescence-related genes (p16INK4a , P19ARF , p27Kip1 ) and proteins (p16INK4a , p27Kip1 ) was decreased in Sca-1+ chimeric hearts, especially in the young group. Host cardiac endothelial cells (GFP- CD31+ ) but not cardiomyocytes were the primary cell type rejuvenated by young Sca-1+ cells as shown by improved proliferation, migration, and tubular formation abilities. C-X-C chemokine CXCL12 was the factor most highly expressed in homed donor BM (GFP+ ) cells isolated from young Sca-1+ chimeric hearts. Protein expression of Cxcr4, phospho-Akt, and phospho-FoxO3a in endothelial cells derived from the aged chimeric heart was increased, especially in the young Sca-1+ group. Reconstitution of aged BM with young Sca-1+ cells resulted in effective homing of functional stem cells in the aged heart. These young, regenerative stem cells promoted aged heart rejuvenation through activation of the Cxcl12/Cxcr4 pathway of cardiac endothelial cells.

Redirecting Ag specificity by transfer of TCR genes into PBLs is an attractive method to generate large numbers of cytotoxic T cells for immunotherapy of cancer and viral diseases. However, transferred TCR chains can pair with endogenous TCR chains, resulting in the formation of mispaired TCR dimers and decreased or unspecific reactivity. TCR gene transfer into hematopoietic stem cells (HSCs) is an alternative to create T cells with desired Ag specificity, because in this case expression of endogenous TCR chains is then less likely owing to allelic exclusion. We generated TCR-transduced T cells from peripheral T cells using the lymphocytic choriomeningitis virus-specific P14 TCR. After transfer of the P14 TCR genes into HSCs and subsequent reconstitution of irradiated mice, TCR-engineered HSC-derived T cells were produced. We then compared the Ag-specific T cell populations with P14 TCR-transgenic T cells for their therapeutic efficiency in three in vivo models. In this study, we demonstrate that TCR-transduced T cells and TCR-engineered HSC-derived T cells are comparable in controlling lymphocytic choriomeningitis virus infection in mice and suppress growth of B16 tumor cells expressing the cognate Ag in a comparable manner.