TSPO-ligands prevent oxidative damage and inflammatory response in C6 glioma cells by neurosteroid synthesis.
Translocator protein 18kDa (TSPO) is predominantly located in the mitochondrial outer membrane, playing an important role in steroidogenesis, inflammation, cell survival and proliferation. Its expression in central nervous system, mainly in glial cells, has been found to be upregulated in neuropathology, and brain injury. In this study, we investigated the anti-oxidative and anti-inflammatory effects of a group of TSPO ligands from the N,N-dialkyl-2-phenylindol-3-ylglyoxylamide class (PIGAs), highlighting the involvement of neurosteroids in their pharmacological effects. To this aim we used a well-known in vitro model of neurosteroidogenesis: the astrocytic C6 glioma cell line, where TSPO expression and localization, as well as cell response to TSPO ligand treatment, have been established. All PIGAs reduced l-buthionine-(S,R)-sulfoximine (BSO)-driven cell cytotoxicity and lipid peroxidation. Moreover, an anti-inflammatory effect was observed due to the reduction of inducible nitric oxide synthase and cyclooxygenase-2 induction in LPS/IFNγ challenged cells. Both effects were blunted by aminoglutethimide (AMG), an inhibitor of pregnenolone synthesis, suggesting neurosteroids' involvement in PIGA protective mechanism. Finally, pregnenolone evaluation in PIGA exposed cells revealed an increase in its synthesis, which was prevented by AMG pre-treatment. These findings indicate that these TSPO ligands reduce oxidative stress and pro-inflammatory enzymes in glial cells through the de novo synthesis of neurosteroids, suggesting that these compounds could be potential new therapeutic tools for the treatment of inflammatory-based neuropathologies with beneficial effects possibly comparable to steroids, but potentially avoiding the negative side effects of long-term therapies with steroid hormones.
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Anna
A
Santoro
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Giuseppina
G
Mattace Raso
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Sabrina
S
Taliani
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Eleonora
E
Da Pozzo
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Francesca
F
Simorini
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Barbara
B
Costa
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Claudia
C
Martini
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Sonia
S
Laneri
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Antonia
A
Sacchi
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Barbara
B
Cosimelli
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy.
Antonio
A
Calignano
Department of Pharmacy, University of Pisa, 56126 Pisa, Italy.
Federico
F
Da Settimo
Department of Pharmacy, University of Naples Federico II, 80131 Naples, University of Pisa, 56126 Pisa, Italy. Electronic address: meli@unina.it.
Rosaria
R
Meli
D000818:Animals; D002352:Carrier Proteins / Q000819:agonists*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D007249:Inflammation / Q000188:drug therapy* / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D011963:Receptors, GABA-A
D002352:Carrier Proteins; D018377:Neurotransmitter Agents; D011963:Receptors, GABA-A; C069997:Tspo protein, rat
Aminoglutethimide; C6 glioma cells; Inflammation; N,N-dialkyl-2-phenylindol-3-ylglyoxylamides; Oxidative stress; Pregnenolone