Project description:Ischemic stroke induces pathological glycogen deposition in astrocytes, but its role in post-injury neural dysfunction remains undefined. We firstly intend to identify the glycogen granule proteome after ischemic stroke via glycogen pulldown for protein mass spectrometry detection. KEGG pathway analysis of the glycogen granule proteome revealed highly enriched mitochondrial-related functional signals, such as respiratory chain complexes, mitochondrial respirasomes, and mitochondrial membrane protein complexes. GO functional annotation of biological processes revealed enrichment of genes related to mitochondrial electron transport, respiratory chain complexes, and mitochondrial ATP synthesis. To explore detailed mitochondrial biological processes in detail, we summarized mitochondrial function gene sets from the mitoproteome database and intersected them with many glycogen-enriched proteins. The data revealed that glycogen stress granules are related mainly to oxidative phosphorylation subunits, assembly factors and electron carriers; mitochondrial dynamics (such as MFF, DNM1L, and GDAP1), homeostasis, and quality control (such as AFG3L2, CLPB, and ATAD3A). Evidence from our experimental data has shown that ATAD3A oligomerization requires the accumulation of astrocytic glycogen stress granules. Under physiological conditions, ATAD3A does not oligomerize, and mitochondria do not exhibit obvious dysfunction in nonglycogen stress granule-deposited cells. To explore what candidate partners are involved with ATAD3A. The proximity-biotinylating enzyme TurboID was reconstituted with ATAD3A to detect biotinylated proteins adjacent to ATAD3A. We next constructed a stable ATAD3A-TurboID cell line (or primary astrocytes). Pulldown biotinylated proteins were subjected to quantitative high-resolution mass spectrometry. Based on the above mass spectrometry data and a series of experimental results, we found that: glycogen-laden astrocytes in the ischemic penumbra undergo HDAC3-dependent mitochondrial fragmentation via a stress granule-mediated mechanism, exacerbating neuronal injury and hindering functional recovery. Mechanistic studies demonstrate that glycogen aggregates sequester cytoplasmic HDAC3, enabling its translocation to mitochondria. There, HDAC3 deacetylates outer mitochondrial membrane protein ATAD3A, promoting oligomerization-driven mitochondrial fission. Astrocyte-specific ATAD3A ablation prevents stroke-induced synaptic disorganization, neural circuit disruption, and cognitive deficits. Therapeutically, combined administration of cotadutide (a glycogen-depleting GLP-1/GCGR agonist) and HDAC3 inhibitor RGFP966 reverses glycogen accumulation, rescues mitochondrial architecture/function, and restores synaptic plasticity and circuit reorganization, thereby accelerating sensorimotor recovery.

Project description:Osteoporosis is the consequence of altered bone metabolism resulting in the systemic reduction of bone strength and increased risk of fragility fractures. MicroRNAs (miRNAs) regulate gene expression on a post-transcriptional level are known to take part in the control of bone formation and bone resorption. Recently, targeted secretion of miRNAs from cells originating from various tissues has been described, which allows for their minimal-invasive detection in serum/plasma and use as biomarkers for presence and progression of pathological conditions. One pilot study has reported circulating miRNAs in serum and tissue of fracture patients. However, further studies are required to explore whether a dysbalance in bone homeostasis of fracture patients can reliably be reflected by specific circulating miRNAs, and whether these miRNAs might serve as drugable targets. Here, we report results from a comprehensive multiplex study of 175 miRNAs in serum samples obtained from 7 patients with osteoporotic fractures at the femoral neck, and 7 age-matched controls. Following elaborate quality control statistical analysis of this exploratory dataset identified 9 microRNAs with altered serum levels in response to fracture (adjusted p-value < 0.1). Of these, hsa-miR-10a/b gave excellent discrimination of both groups (AUC = 1.0), and clustering of samples based on the top10 miRNAs confirmed the high discriminatory power of circulating microRNAs for osteoporotic fractures. In the next step 3 miRNAs with unknown roles in osteogenic differentiation and 4 miRNA from a previous study were tested for their effects on osteogenic differentiation. Of these, 3 miRNAs showed robust effects on osteogenic differentiation. Overall, these data provide important insights into changes in serum miRNA in post-traumatic patients. Future studies will show, whether this knowledge can be used to improve current diagnostic methodologies to predict fracture risk and design novel treatment strategies for osteoporosis patients. Two groups with n=7 per group; one groups represents cases with osteoporotic fractures, the control group is age-matched without fractures

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Transcription profiling of Drosophila embryos with differenct ewg transcription factor isoforms identifies a subset of differentially regulated genes important for synaptic growth regulation

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