Bone marrow stromal cells dictate lanosterol biosynthesis and ferroptosis of multiple myeloma.

Ferroptosis has been demonstrated a promising way to counteract chemoresistance of multiple myeloma (MM), however, roles and mechanism of bone marrow stromal cells (BMSCs) in regulating ferroptosis of MM cells remain elusive. Here, we uncovered that MM cells were more susceptible to ferroptotic induction under the interaction of BMSCs using in vitro and in vivo models. Mechanistically, BMSCs elevated the iron level in MM cells, thereby activating the steroid biosynthesis pathway, especially the production of lanosterol, a major source of reactive oxygen species (ROS) in MM cells. We discovered that direct coupling of CD40 ligand and CD40 receptor constituted the key signaling pathway governing lanosterol biosynthesis, and disruption of CD40/CD40L interaction using an anti-CD40 neutralizing antibody or conditional depletion of Cd40l in BMSCs successfully eliminated the iron level and lanosterol production of MM cells localized in the Vk*MYC Vk12653 or NSG mouse models. Our study deciphers the mechanism of BMSCs dictating ferroptosis of MM cells and highlights the therapeutic potential of non-apoptosis strategies for managing refractory or relapsed MM patients.

Long-term benefits of hematopoietic stem cell-based macrophage/microglia delivery of GDNF to the CNS in a mouse model of Parkinson's disease.

Glial cell line-derived neurotrophic factor (GDNF) protects dopaminergic neurons in various models of Parkinson's disease (PD). Cell-based GDNF gene delivery mitigates neurodegeneration and improves both motor and non-motor functions in PD mice. As PD is a chronic condition, this study aims to investigate the long-lasting benefits of hematopoietic stem cell (HSC)-based macrophage/microglia-mediated CNS GDNF (MMC-GDNF) delivery in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model. The results indicate that GDNF treatment effectively ameliorated MPTP-induced motor deficits for up to 12 months, which coincided with the protection of nigral dopaminergic neurons and their striatal terminals. Also, the HSC-derived macrophages/microglia were recruited selectively to the neurodegenerative areas of the substantia nigra. The therapeutic benefits appear to involve two mechanisms: (1) macrophage/microglia release of GDNF-containing exosomes, which are transferred to target neurons, and (2) direct release of GDNF by macrophage/microglia, which diffuses to target neurons. Furthermore, the study found that plasma GDNF levels were significantly increased from baseline and remained stable over time, potentially serving as a convenient biomarker for future clinical trials. Notably, no weight loss, altered food intake, cerebellar pathology, or other adverse effects were observed. Overall, this study provides compelling evidence for the long-term therapeutic efficacy and safety of HSC-based MMC-GDNF delivery in the treatment of PD.

NAT10-mediated mRNA N4-acetylcytidine modification of MDR1 and BCRP promotes breast cancer progression.

BACKGROUND: N-acetyltransferase 10 (NAT10) serves as a critical enzyme in mediating the N4-acetylcytidine (ac4C) that ensures RNA stability and effective translation processes. The role of NAT10 in driving the advancement of breast cancer remains uninvestigated. METHODS: We observed an increase in NAT10 expression, both at mRNA level through the analysis of the Cancer Genome Atlas (TCGA) database and at the protein level of tumor tissues from breast cancer patients. We determined that a heightened expression of NAT10 served as a predictor of an unfavorable clinical outcome. By screening the Cancer Cell Line Encyclopedia (CCLE) cell bank, this expression pattern of NAT10 was consistency found across almost all the classic breast cancer cell lines. RESULTS: Functionally, interference of NAT10 expression exerts an inhibitory effect on proliferation and invasion of breast cancer cells. By using ac4C RNA immunoprecipitation (ac4c-RIP) and acRIP-qPCR assays, we identified a reduction of ac4C enrichment within the ATP binding cassette (ABC) transporters, multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP), consequent to NAT10 suppression. Expressions of MDR1 and BCRP exhibited a positive correlation with NAT10 expression in tumor tissues, and the inhibition of NAT10 in breast cancer cells resulted in a decrease of MDR1 and BCRP expression. Therefore, the overexpressing of MDR1 and BCRP could partially rescue the adverse consequences of NAT10 depletion. In addition, we found that, remodelin, a NAT10 inhibitor, reinstated the susceptibility of capecitabine-resistant breast cancer cells to the chemotherapy, both in vitro and in vivo. CONCLUSION: The results of our study demonstrated the essential role of NAT10-mediated ac4c-modification in breast cancer progression and provide a novel strategy for overcoming chemoresistance challenges.