The protective effect of the TSPO ligands 2,4-Di-Cl-MGV-1, CB86, and CB204 against LPS-induced M1 pro-inflammatory activation of microglia.

We have shown previously, that the 18 â€‹kDa translocator protein (TSPO) synthetic ligands quinazoline derivatives (2-Cl-MGV-1 and MGV-1) can inhibit activation of in BV-2 microglial cells. In the present study we assessed the impact of novel TSPO ligands on lipopolysaccharide (LPS)-induced microglial activation as expressed by release of pro-inflammatory molecules, including cytokines [interleukin-6 (IL-6), IL-1ß, interferon- γ (IFN-γ)] nitric oxide (NO), CD8, and cyclo-oxygenase-2 (COX-2). The TSPO ligands 2,4-Di-Cl-MGV-1, CB86, and CB204 counteracted with the LPS-induced microglial activation. Exposure to LPS along with the TSPO ligand 2,4-Di-Cl-MGV-1 (25 â€‹µM) reduced significantly the release of NO by 24-, IL-6 by 14-, IL-ß by 14-, IFN- γ by 6-, and TNF-α by 29-folds, respectively. In contrast to the anti-neuroinflammatory effect of the TSPO ligands, the effect of diclofenac sodium (DS; 25 â€‹µM) did not reach statistical significance. No alterations in IL-10 and IL-13 were detected (M2 anti-inflammatory pathway) during the inhibition of M1 pro-inflammatory pathway.

Inhibitory Effects of the Two Novel TSPO Ligands 2-Cl-MGV-1 and MGV-1 on LPS-induced Microglial Activation.

The 18 kDa translocator protein (TSPO) ligands 2-Cl-MGV-1 and MGV-1 can attenuate cell death of astrocyte-like cells (U118MG) and induce differentiation of neuronal progenitor cells (PC-12). Lipopolysaccharide (LPS) is a bacterial membrane endotoxin that activates cellular inflammatory pathways by releasing pro-inflammatory molecules, including cytokines and chemokines. The aim of the present study was to assess the immuno-modulatory effect of TSPO ligands in activated microglial cells. We demonstrated that the TSPO ligands 2-Cl-MGV-1 and MGV-1 can prevent LPS-induced activation of microglia (BV-2 cell line). Co-treatment of LPS (100 ng/mL) with these TSPO ligands (final concentration- 25 µM) reduces significantly the LPS-induced release of interleukin-6 (IL-6) from 16.9-fold to 2.5-fold, IL-ß from 8.3-fold to 1.6-fold, interferon-γ from 16.0-fold to 2.2-fold, and tumor necrosis factor-α from 16.4-fold to 1.8-fold. This anti-inflammatory activity seems to be achieved by inhibition of NF-κB p65 activation. Assessment of initiation of ROS generation and cell metabolism shows significant protective effects of these two novel TSPO ligands. The IL-10 and IL-13 levels were not affected by any of the TSPO ligands. Thus, it appears that the ligands suppress the LPS-induced activation of some inflammatory responses of microglia. Such immunomodulatory effects may be relevant to the pharmacotherapy of neuro-inflammatory diseases.

Malignant salivary gland tumors and cyclo-oxygenase-2: a histopathological and immunohistochemical analysis with implications on histogenesis.

The classification system for malignant salivary gland tumors (MST) is largely dependent on its histogenesis. The histogenesis is uncertain but the "bicellular theory of origin" has been accepted by most and states that malignant transformation of reserve cells from either the intercalated or excretory duct are responsible for the development of MST. Cyclooxygenase-2 (cox-2), a potential molecular marker for MST, was analyzed on a series (n=56) of MST with the aim of determining the morphological MST subtypes capable of cox-2 overexpression and correlating its expression with histogenesis. Fifty six primary major and minor gland MST were stained with anti-cox-2 antibody and rated with a combined score that added a scale of intensity to the percentage of tumor cells that overexpressed the cox-2 protein. A score of <3: negligible or negative staining; score of 4-5; moderate staining; score of 6-7; strong staining. Tumor types were segregated by morphology, histological features and proposed histogenesis. Strong cox-2 overexpression was noted in all MST of proposed excretory duct origin: salivary duct carcinoma (100%), mucoepidermoid carcinoma (MEC) (92%), and adenocarcinoma nos (AdC nos) (83%). Primary squamous cell carcinoma (PSCC) was the exception. Negative expression was noted in all tumors of proposed intercalated duct origin (adenoid cystic carcinoma, basal cell adenocarcinoma and acinic cell carcinoma) with the exception of one case of polymorphous low grade adenocarcinoma. Strong cox-2 overexpression was noted in the epidermoid cells of MEC, abluminal duct cells surrounding the duct-like structures and ductal cells of AdC nos and salivary duct carcinoma. Myoepithelial and acinar cells were unreactive. Although preliminary, the results of our study support the concept that MST of proposed excretory duct origin share a common histogenesis. Negligible cox-2 expression in PSCC may provide a useful tool for diagnosing the often histologically indistinguishable cases of high grade MEC. Follow-up studies on a larger series of MST are warranted.