Prostaglandin E₂Produced by Alginate-Encapsulated Mesenchymal Stromal Cells Modulates the Astrocyte Inflammatory Response

Abstract

Astroglia are well known for their role in propagating secondary injury following brain trauma. Modulation of this injury cascade, including inflammation, is essential to repair and recovery. Mesenchymal stromal cells (MSCs) have been demonstrated as trophic mediators in several models of secondary CNS injury, however, there has been varied success with the use of direct implantation due to a failure to persist at the injury site. To achieve sustained therapeutic benefit, we have encapsulated MSCs in alginate microspheres and evaluated the ability of these encapsulated MSCs to attenuate neuro-inflammation. In this study, astroglial cultures were administered lipopolysaccharide (LPS) to induce inflammation and immediately co-cultured with encapsulated or monolayer human MSCs. Cultures were assayed for the pro-inflammatory cytokine tumor necrosis factor alpha (TNF-α) produced by astroglia, MSC-produced prostaglandin E2, and expression of neurotrophin-associated genes. We found that encapsulated MSCs significantly reduced TNF-α produced by LPS-stimulated astrocytes, more effectively than monolayer MSCs, and this enhanced benefit commences earlier than that of monolayer MSCs. Furthermore, in support of previous findings, encapsulated MSCs constitutively produced high levels of PGE2, while monolayer MSCs required the presence of inflammatory stimuli to induce PGE2 production. The early, constitutive presence of PGE2 significantly reduced astrocyte-produced TNF-α, while delayed administration had no effect. Finally, MSC-produced PGE2 was not only capable of modulating inflammation, but appears to have an additional role in stimulating astrocyte neurotrophin production. Overall, these results support the enhanced benefit of encapsulated MSC treatment, both in modulating the inflammatory response and providing neuroprotection.

Assessment of Enrichment of Human Mesenchymal Stem Cells Based on Plasma and Mitochondrial Membrane Potentials

“…This was selected to be consistent and comparable with prior work that assessed immunomodulatory effects of hMSCs on target cell types. 71 After 4 h to allow for hMSCs to settle and attach, media were changed to remove dead cells and debris, and inserts containing M(LPS+IFNc) were added to the appropriate hMSC wells. Fresh 500 lL of activated media was added into the transwells.…”

Machine‐Assisted Discovery of Chondroitinase ABC Complexes toward Sustained Neural Regeneration

“…Astrocyte cultures have been established as previously described. [ 12 ] Briefly, astrocytes seeded in 24 well plates were treated with different concentrations of copolymer on the day of the experiment. After 24 h, supernatants were collected, and cell viability was assessed using standard Live/Dead assay.…”

Orai2 channel regulates prostaglandin E2 production in TNFα/IL1α‐stimulated astrocytes

“…EP1 and EP3 receptors are essential for PGE 2 ‐mediated neurotoxicity, whereas EP2 and EP4 receptors are neuroprotective (Liang et al, 2007). PGE 2 receptors also contribute to astrocyte function, and play key roles in neuroinflammation through astrocytic proliferation (Zhang et al, 2009) or production of inflammatory cytokines (Stucky et al, 2017). Astrocytes also produce PGE 2 (Lin et al, 2015; Xia & Zhu, 2011), but the mechanism and role of PGE 2 produced by these cells under inflammatory conditions are unclear.…”