» Articles » PMID: 38918312

TLR3-mediated Astrocyte Responses in High and Normal Glucose Adaptation Differently Regulated by Metformin

Overview
Date 2024 Jun 25
PMID 38918312
Authors
Affiliations
Soon will be listed here.
Abstract

Toll-like receptors 3 (TLR3) are innate immune receptors expressed on a wide range of cell types, including glial cells. Inflammatory responses altered by hyperglycemia highlight the need to explore the molecular underpinnings of these changes in cellular models. Therefore, here we estimated TLR3-mediated response of astrocytes cultured at normal (NG, 5 mM) and high (HG, 22.5 mM) glucose concentrations for 48 h before stimulation with polyinosinic:polycytidylic acid Poly(I:C) (PIC) for 6 h. Seahorse Extracellular Flux Analyzer (Seahorse XFp) was used to estimate the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Although adaptation to HG affected ECAR and OCR, the stimulation of cells with PIC had no effect on ECAR. PIC reduced maximal OCR, but this effect disappeared upon adaptation to HG. PIC-stimulated release of cytokines IL-1β, IL-10 was reduced, and that of IL-6 and iNOS was increased in the HG model. Adaptation to HG reduced PIC-stimulated synthesis of COX-derived oxylipins measured by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Adaptation to HG did not alter PIC-stimulated p38 activity, ERK mitogen-activated protein kinase, STAT3 and ROS production. Metformin exhibited anti-inflammatory activity, reducing PIC-stimulated synthesis of cytokines and oxylipins. Cell adaptation to high glucose concentration altered the sensitivity of astrocytes to TLR3 receptor activation, and the hypoglycemic drug metformin may exert anti-inflammatory effects under these conditions.

References
1.
Ristow M . Neurodegenerative disorders associated with diabetes mellitus. J Mol Med (Berl). 2004; 82(8):510-29. DOI: 10.1007/s00109-004-0552-1. View

2.
Jafar N, Edriss H, Nugent K . The Effect of Short-Term Hyperglycemia on the Innate Immune System. Am J Med Sci. 2016; 351(2):201-11. DOI: 10.1016/j.amjms.2015.11.011. View

3.
Belanger M, Allaman I, Magistretti P . Brain energy metabolism: focus on astrocyte-neuron metabolic cooperation. Cell Metab. 2011; 14(6):724-38. DOI: 10.1016/j.cmet.2011.08.016. View

4.
Selvarajah D, Tesfaye S . Central nervous system involvement in diabetes mellitus. Curr Diab Rep. 2006; 6(6):431-8. DOI: 10.1007/s11892-006-0075-y. View

5.
Farina C, Aloisi F, Meinl E . Astrocytes are active players in cerebral innate immunity. Trends Immunol. 2007; 28(3):138-45. DOI: 10.1016/j.it.2007.01.005. View