Biology subjects

Ciesielska, A.

Publications and source records attributed to Ciesielska, A..

4 recordsLinked to original sources

bioRxiv2025

Diacylglycerol kinase-ε is required for the formation of GPI-anchored CD14 and modulates the LPS-induced proinflammatory responses of macrophages

Diacylglycerol kinase-{varepsilon} (DGK{varepsilon}) is a unique member of the DGK family with strict specificity toward DAG containing stearic and arachidonic fatty acid residues, called SAG, and producing phosphatidic acid used for the synthesis of phosphatidylinositol (PI). PI and its derivatives, both phosphorylated and non-phosphorylated ones, regulate a multitude of processes, including the signaling of diverse plasma membrane receptors. To the latter belong Toll-like receptor 4 (TLR4) and its accessory CD14 protein activated in macrophages by bacterial lipopolysaccharide (LPS). To assess the role of DGK{varepsilon} in the LPS-induced pro-inflammatory responses, we obtained Raw264 cells stably depleted of DGK{varepsilon} and subsequently rescued them with DGK{varepsilon}-Myc expressed at a level similar to the native one. As a result, SAG phosphorylation was markedly decreased and then restored in those cells, with the activity of other DGKs unaffected. The depletion of DGK{varepsilon} nullified the LPS-induced pro-inflammatory signaling of TLR4 dependent on CD14-mediated internalization of TLR4 and the TRIF engagement in endosomes. In contrast, the MyD88-dependent signaling pathway, for which CD14 involvement can be dispensible, was inhibited only partially. In accordance, no mature, GPI-anchored form of CD14 was produced in the DGK{varepsilon}-depleted cells and no CD14 was found on the cell surface. The reintroduction of DGK{varepsilon} restored both the abundance of GPI-CD14 and the CD14-dependent signaling of TLR4. These results indicate that the DGK{varepsilon}-dependent phosphorylation of SAG controls the synthesis of the pool of PI that serves for the biosynthesis of the GPI moiety of CD14. We thereby have identified DGK{varepsilon} as a key factor determining the sensitivity of macrophages to LPS.

immunology↗

bioRxiv2024

Type 1 lymphocytes and interferon-γ accumulate in the thalamus and restrict seizure susceptibility after traumatic brain injury

Chronic neural circuit hyperexcitability frequently emerges after brain injury, but endogenous mechanisms constraining runaway activity remain poorly understood. Here, we reveal that the adaptive immune system acts as a homeostatic brake on network excitability following traumatic brain injury (TBI). In mice, cortical trauma triggered a delayed infiltration of interferon-{gamma} (IFN{gamma})-producing type 1 lymphocytes into the sensory thalamus. Rather than driving pathology, IFN{gamma} signaling directly in neurons restricted thalamocortical network hyperexcitability. This protective axis was tonically regulated; depleting CD4 T cells de-repressed local non-CD4 type 1 lymphocytes, elevating IFN{gamma} signaling and protecting from seizures. A single dose of exogenous IFN{gamma} abolished hypersynchronous circuit bursting and rescued injury-induced seizure incidence, severity, and mortality, establishing a therapeutic framework for safeguarding circuit stability after brain injury.

immunology↗

bioRxiv2024

Dynamic fibroblast-immune interactions shape wound healing after brain injury

Fibroblasts coordinate the response to tissue injury, directing organ regeneration versus scarring. In the central nervous system (CNS), fibroblasts are uncommon cells enriched at tissue borders, and their molecular, cellular, and functional interactions after brain injury are poorly understood. Here we define the fibroblast response to sterile brain damage across time and space. Early pro-fibrotic myofibroblasts infiltrated CNS lesions and were functionally and spatially organized by fibroblast TGF{beta} signaling, pro-fibrotic macrophages and microglia, and perilesional brain glia that activated TGF{beta} via integrin v{beta}8. Early myofibroblasts subsequently transitioned into a variety of late states, including meningeal and lymphocyte-interactive fibroblasts that persisted long term. Interruption of this dynamic fibroblast-macrophage-glial coordination impaired brain wound healing and the resolution of neuroinflammation, disrupted generation of late de novo CNS lymphocyte niches, and increased mortality in a stroke model. This work highlights an unexpected role of fibroblasts as coordinate regulators of CNS healing and neuroinflammation after brain injury.

immunology↗

bioRxiv2023

Flotillins affect LPS-induced TLR4 signaling by modulating the trafficking and abundance of CD14

Lipopolysaccharide induces a strong pro-inflammatory reaction of macrophages upon activation of Toll-like 4 receptor (TLR4) with the assistance of CD14 protein. Considering a key role of plasma membrane rafts in CD14 and TLR4 activity and the significant impact exerted on that activity by endocytosis and intracellular trafficking of the both LPS acceptors, it seemed likely that the pro-inflammatory reaction could be modulated by flotillins. Flotillin-1 and -2 are scaffolding proteins associated with plasma membrane rafts and also with endo-membranes, affecting both the plasma membrane dynamics and intracellular protein trafficking. To verify the above hypothesis, a set of shRNA was used to down-regulate flotillin-2 in Raw264 cells, which were found to also become deficient in flotillin-1. The flotillin deficiency inhibited strongly the TRIF-dependent endosomal signaling of LPS-activated TLR4, and to a lower extent also the MyD88-dependent one, without affecting the cellular level of TLR4. In contrast, the depletion of flotillins down-regulated the CD14 mRNA level and the total cellular content of CD14 protein, and decreased the amount of CD14 on the cell surface. The constitutive CD14 endocytosis remained unchanged but CD14 recycling was enhanced via EEA1-positive early endosomes and golgin-97-positive trans-Golgi network, likely to compensate for the depletion of the cell-surface CD14. Notably, a paucity of surface CD14 in resting cells can inhibit TLR4 signaling after the stimulation of cells with LPS. In conclusion, we have shown here that flotillins modulate the pro-inflammatory response of macrophages to LPS by affecting the abundance of CD14.

immunology↗