The TSPO Ligands 2-Cl-MGV-1, MGV-1, and PK11195 Differentially Suppress the Inflammatory Response of BV-2 Microglial Cell to LPS

Abstract

The 18 kDa Translocator Protein (TSPO) is a marker for microglial activation as its expression is enhanced in activated microglia during neuroinflammation. TSPO ligands can attenuate neuroinflammation and neurotoxicity. In the present study, we examined the efficacy of new TSPO ligands designed by our laboratory, MGV-1 and 2-Cl-MGV-1, in mitigating an in vitro neuroinflammatory process compared to the classic TSPO ligand, PK 11195. We exposed BV-2 microglial cells to lipopolysaccharide (LPS) for 24 h to induce inflammatory response and added the three TSPO ligands: (1) one hour before LPS treatment (pretreatment), (2) simultaneously with LPS (cotreatment), and (3) one hour after LPS exposure (post-treatment). We evaluated the capability of TSPO ligands to reduce the levels of three glial inflammatory markers: cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and nitric oxide (NO). We compared the effects of the two novel ligands to PK 11195. Both 2-Cl-MGV-1 and MGV-1 reduced the levels of glial COX-2, iNOS, and NO in LPS-treated BV-2 cells more efficiently than PK 11195. Notably, even when added after exposure to LPS, all ligands were able to suppress the inflammatory response. Due to their pronounced anti-inflammatory activity, 2-Cl-MGV-1 and MGV-1 may serve as potential therapeutics in neuroinflammatory and neurodegenerative diseases.

Diagnostic and Therapeutic Potential of TSPO Studies Regarding Neurodegenerative Diseases, Psychiatric Disorders, Alcohol Use Disorders, Traumatic Brain Injury, and Stroke: An Update

“…Additionally, the authors concluded that the neuroprotective effect of Emapunil might be associated with the partial alteration of neurosteroid levels, which can counteract neuroinflammatory responses [65]. Together with other studies applying TSPO ligands for the treatment of brain damage, this investigation showed promising results about exploiting TSPO as a possible therapeutic target for α-synucleinopathies [28,66]. However, greater efforts must be made to fully disclose the influence of TSPO ligands on dopaminergic degeneration.…”

18-kDa Translocator Protein Ligands Protect H9C2 Cardiomyocytes from Cigarette Smoke-induced Cell Death: In Vitro Study

“…TSPO has low affinity for these ligands (both approximately 825 nM) due to the elongation of the alkyl side chains, which reduces their lethal effects as compared to the classical TSPO ligands as described previously (21,22). The anti-inflammatory effects of MGV-1 and 2-Cl-MGV-1 were described previously (23).…”

“…Initially, two concentrations of the ligands were used based on preliminary studies, 1 and 25 μM final concentrations. Eventually, the chosen final concentration of the ligands in the current study was 25 μM, as used previously (22,23). Following incubation, the cells were exposed to CS for 30 and 60 min in order to optimize the cell death assays.…”

“…Inhibitory effects on inflammatory reactions of these have been described (22). TSPO has low affinities for these ligands (both approximately 825 nM) due to their elongated alkyl side chains, which results in reduced lethal effects as compared to the classical TSPO ligands as described previously (21,23).…”

Effect of Glycine on BV-2 Microglial Cells Treated with Interferon-γ and Lipopolysaccharide

“…The present study was performed to reveal to what extent glycine affected the viability, activation state and secretory activity of microglial cells during inflammation. BV-2 cells were stressed with a combination of LPS and IFN-γ over 24 h. LPS is the most common pro-inflammatory stimulus and causes inflammatory reactions in primary microglia and BV-2 cells [17,18], and IFN-γ is released during CNS injury [18][19][20]. Approximately 90% of the genes induced in BV-2 cells after LPS exposure were also found in primary microglia and showed similar reaction patterns [21], which warrants this cell line as a suitable experimental model.…”