Similar Datasets
Project description:Hematopoietic stem cells (HSCs) survive many types of cellular stress but often lose their regenerative and lymphopoietic capacities as a result. Such functional decline also occurs with age, and dysfunctional HSCs with impaired mitochondria accumulate during aging. However, the molecular link between HSC stress response and age-related functional decline remains poorly understood. Here we show that multiple stress responses converge on the RIPK3-MLKL axis to induce age-related changes in HSCs. The necroptosis effector MLKL is readily activated by inflammation and replication stress and accumulates in HSC mitochondria. Consequently, activated MLKL does not cause cell death but impairs HSC self-renewal and lymphoid differentiation. Such MLKL-mediated functional decline also occurs in HSCs during organismal aging, with activated MLKL primarily mediating age-related mitochondrial damage and reduced glycolytic flux. Collectively, our results establish the RIPK3-MLKL axis as a key mediator of HSC aging and identify a necroptosis-independent role of MLKL in mitochondrial damage.
2026-02-10 | GSE285110 | GEO
Project description:Hematopoietic stem cells (HSCs) survive many types of cellular stress but often lose their regenerative and lymphopoietic capacities as a result. Such functional decline also occurs with age, and dysfunctional HSCs with impaired mitochondria accumulate during aging. However, the molecular link between HSC stress response and age-related functional decline remains poorly understood. Here we show that multiple stress responses converge on the RIPK3-MLKL axis to induce age-related changes in HSCs. The necroptosis effector MLKL is readily activated by inflammation and replication stress and accumulates in HSC mitochondria. Consequently, activated MLKL does not cause cell death but impairs HSC self-renewal and lymphoid differentiation. Such MLKL-mediated functional decline also occurs in HSCs during organismal aging, with activated MLKL primarily mediating age-related mitochondrial damage and reduced glycolytic flux. Collectively, our results establish the RIPK3-MLKL axis as a key mediator of HSC aging and identify a necroptosis-independent role of MLKL in mitochondrial damage.
2026-02-10 | GSE285109 | GEO
Project description:Non-necroptotic MLKL function damages mitochondria and promotes hematopoietic stem cell aging
| PRJNA1201182 | ENA
Project description:Non-necroptotic MLKL function damages mitochondria and promotes hematopoietic stem cell aging [ATAC-seq]
| PRJNA1201189 | ENA
Project description:Non-necroptotic MLKL function damages mitochondria and promotes hematopoietic stem cell aging [RNA-seq]
| PRJNA1201190 | ENA
Project description:Mixed-lineage kinase domain-like protein (MLKL) is known as the terminal executor of necroptosis. However, its function outside of necroptosis is still not clear. Herein, we demonstrate that MLKL promotes vascular inflammation by regulating the expression of adhesion molecules ICAM1, VCAM1, and E-selectin in endothelial cells (EC). MLKL deficiency suppresses the expression of these adhesion molecules, thereby reducing EC-leukocyte interaction in vitro and in vivo. Mechanistically, we show that MLKL interacts with RBM6 to promote the mRNA stability of adhesion molecules. In conclusion, this study identified a novel role of MLKL in regulating endothelial adhesion molecule expression and local EC-leukocyte interaction during acute inflammation.
| S-EPMC7181788 | biostudies-literature
Project description:Age-related defects in stem cells can limit proper tissue maintenance and hence contribute to a shortened lifespan. Using highly purified hematopoietic stem cells from mice aged 2 to 21 mo, we demonstrate a deficit in function yet an increase in stem cell number with advancing age. Expression analysis of more than 14,000 genes identified 1,500 that were age-induced and 1,600 that were age-repressed. Genes associated with the stress response, inflammation, and protein aggregation dominated the up-regulated expression profile, while the down-regulated profile was marked by genes involved in the preservation of genomic integrity and chromatin remodeling. Many chromosomal regions showed coordinate loss of transcriptional regulation; an overall increase in transcriptional activity with age and inappropriate expression of genes normally regulated by epigenetic mechanisms was also observed. Hematopoietic stem cells from early-aging mice expressing a mutant p53 allele reveal that aging of stem cells can be uncoupled from aging at an organismal level. These studies show that hematopoietic stem cells are not protected from aging. Instead, loss of epigenetic regulation at the chromatin level may drive both functional attenuation of cells, as well as other manifestations of aging, including the increased propensity for neoplastic transformation.
| S-EPMC1925137 | biostudies-literature
Project description:BackgroundsThe stimulator of interferon genes (STING) is an important driver in various inflammatory diseases.Methods and resultsHere, we have demonstrated that inhibition of RIPK3 and MLKL dampens STING signaling, indicating that necroptosis may be involved in sustaining STING signaling. Furthermore, RIPK3 knockout in HT-29 cells significantly suppressed STING signaling. Mechanistically, RIPK3 inhibits autophagic flux during STING activation. RIPK3 knockout inhibits STING signaling by intensifying STING autophagy. In contrast, MLKL regulates the STING pathway bidirectionally. MLKL deficiency enhances STING signaling, whereas suppression of MLKL-mediated pore formation restricts STING signaling. Mechanistically, upon abrogating the pro-necroptotic activity of MLKL, MLKL bound to activated STING is secreted to the extracellular space, where it restricts TBK1 and IRF3 recruitment. Targeting necroptotic signaling ameliorates STING activation during DMXAA-induced intestinal injury and sepsis.ConclusionsThese findings elucidate molecular mechanisms linking necroptosis to the STING pathway, and suggest a potential benefit of therapeutic targeting of necroptosis in STING-driven inflammatory diseases.
| S-EPMC10359592 | biostudies-literature
Project description:Neutrophil extracellular trap (NET) formation can generate short-term, functional anucleate cytoplasts and trigger loss of cell viability. We demonstrated that the necroptotic cell death effector mixed lineage kinase domain-like (MLKL) translocated from the cytoplasm to the plasma membrane and stimulated downstream NADPH oxidase-independent ROS production, loss of cytoplasmic granules, breakdown of the nuclear membrane, chromatin decondensation, histone hypercitrullination, and extrusion of bacteriostatic NETs. This process was coordinated by receptor-interacting protein kinase-1 (RIPK1), which activated the caspase-8-dependent apoptotic or RIPK3/MLKL-dependent necroptotic death of mouse and human neutrophils. Genetic deficiency of RIPK3 and MLKL prevented NET formation but did not prevent cell death, which was because of residual caspase-8-dependent activity. Peptidylarginine deiminase 4 (PAD4) was activated downstream of RIPK1/RIPK3/MLKL and was required for maximal histone hypercitrullination and NET extrusion. This work defines a distinct signaling network that activates PAD4-dependent NET release for the control of methicillin-resistant Staphylococcus aureus (MRSA) infection.
| S-EPMC6301070 | biostudies-literature
Project description:Hematopoietic stem cells (HSCs) possess unique gene expression programs that enforce their identity and regulate lineage commitment. Long non-coding RNAs (lncRNAs) have emerged as important regulators of gene expression and cell fate decisions, although their functions in HSCs are unclear. Here we profiled the transcriptome of purified HSCs by deep sequencing and identified 323 unannotated lncRNAs. Comparing their expression in differentiated lineages revealed 159 lncRNAs enriched in HSCs, some of which are likely HSC specific (LncHSCs). These lncRNA genes share epigenetic features with protein-coding genes, including regulated expression via DNA methylation, and knocking down two LncHSCs revealed distinct effects on HSC self-renewal and lineage commitment. We mapped the genomic binding sites of one of these candidates and found enrichment for key hematopoietic transcription factor binding sites, especially E2A. Together, these results demonstrate that lncRNAs play important roles in regulating HSCs, providing an additional layer to the genetic circuitry controlling HSC function.
| S-EPMC4388783 | biostudies-literature