Iron-responsive element of Divalent metal transporter 1 (Dmt1) controls Notch-mediated cell fates

Key Mechanisms in Lysosome Stability, Degradation and Repair

Lysosomes are organelles that play pivotal roles in macromolecule digestion, signal transduction, autophagy, and cellular homeostasis. Lysosome instability, including the inhibition of lysosomal intracellular activity and the leakage of their contents, is associated with various pathologies, including cancer, neurodegenerative diseases, inflammatory diseases and infections. These lysosomal-related pathologies highlight the significance of factors contributing to lysosomal dysfunction. The vulnerability of the lysosomal membrane and its components to internal and external stimuli make lysosomes particularly susceptible to damage. Cells are equipped with mechanisms to repair or degrade damaged lysosomes to prevent cell death. Understanding the factors influencing lysosome stabilization and damage repair is essential for developing effective therapeutic interventions for diseases. This review explores the factors affecting lysosome acidification, membrane integrity, and functional homeostasis and examines the underlying mechanisms of lysosomal damage repair. In addition, we summarize how various risk factors impact lysosomal activity and cell fate.

Study on yolk iron transportation in chick embryo eggs based on transcriptomics

Chick embryo eggs have a complete system of iron release, delivery, and uptake and thus provide a useful tool to study the fast transportation and absorption of iron. Based on this, the regulatory genes and pathways of iron transportation and uptake at the four key stages of chick embryo incubation, days 6, 9, 12, and 15 (E6, E9, E12, and E15), were investigated. Throughout these four key stages, the iron content decreased in egg yolk, increased in chick embryos, and first increased and then decreased in the yolk sac membrane (YSM) with the highest value of 110.38 mg/kg at E12. A total of 87,499 expressed genes were detected by transcriptome, where the specifically expressed genes at E6, E9, E12, and E15 were 312, 466, 280, and 185 respectively. Mineral absorption pathways involved in mineral uptake, transportation, utilization, and metabolism were significantly enriched in stages E9 to E15. The expression of divalent metal transporter 1 (DMT1) and ferritin heavy chain 1 (FTH1) related to iron transportation was up-regulated considerably from E9 to E12. Heme oxygenase 1 (HMOX1), FTH1, Solute Carrier Family 40 Member 1 (SLC40A1), and hephaestin (HEPH) mainly responsible for the regulation of iron transportation and uptake were up-regulated from E12 to E15. Therefore, stage E9 to E12 was the crucial period for iron initiation and transportation, and DMT1 and FTH1 played an important role in regulating the initiation of iron transportation at the early stage of incubation.

The DMT1 isoform lacking the iron-response element regulates normal and malignant hematopoiesis via NOTCH pathway activation

Natural resistance-associated macrophage protein 2 (NRAMP 2; also known as DMT1 and encoded by SLC11A2) is mainly known for its iron transport activity. Recently, the DMT1 isoform lacking the iron-response element (nonIRE) was associated with aberrant NOTCH pathway activity. In this report, we investigated the function of DMT1 nonIRE in normal and malignant hematopoiesis. Knockdown of Dmt1 nonIRE in mice showed that it has non-canonical functions in hematopoietic stem cell differentiation: its knockdown suppressed development along the myeloid and lymphoid lineages, while promoting the production of platelets. These phenotypic effects on the hematopoietic system induced by Dmt1 nonIRE knockdown were linked to suppression of Notch/Myc pathway activity. Conversely, our data indicate a non-canonical function for DMT1 nonIRE overexpression in boosting NOTCH pathway activity in T-cell leukemia homeobox protein 1 (TLX1)-defective leukemia. This work sets the stage for future investigation using a multiple-hit T-cell acute lymphoblastic leukemia (T-ALL) model to further investigate the function of DMT1 nonIRE in T-ALL disease development and progression.