Identification of Corosolic and Oleanolic Acids as Molecules Antagonizing the Human RORγT Nuclear Receptor Using the Calculated Fingerprints of the Molecular Similarity

RORγT is a protein product of the RORC gene belonging to the nuclear receptor subfamily of retinoic-acid-receptor-related orphan receptors (RORs). RORγT is preferentially expressed in Th17 lymphocytes and drives their differentiation from naive CD4+ cells and is involved in the regulation of the expression of numerous Th17-specific cytokines, such as IL-17. Because Th17 cells are implicated in the pathology of autoimmune diseases (e.g., psoriasis, inflammatory bowel disease, multiple sclerosis), RORγT, whose activity is regulated by ligands, has been recognized as a drug target in potential therapies against these diseases. The identification of such ligands is time-consuming and usually requires the screening of chemical libraries. Herein, using a Tanimoto similarity search, we found corosolic acid and other pentacyclic tritepenes in the library we previously screened as compounds highly similar to the RORγT inverse agonist ursolic acid. Furthermore, using gene reporter assays and Th17 lymphocytes, we distinguished compounds that exert stronger biological effects (ursolic, corosolic, and oleanolic acid) from those that are ineffective (asiatic and maslinic acids), providing evidence that such combinatorial methodology (in silico and experimental) might help wet screenings to achieve more accurate results, eliminating false negatives.

Evaluation of correlation between transcription factors and IL-17 in oral and cutaneous lichen planus lesions and Leukocytes

BACKGROUND

Lichen planus (LP) is a chronic autoimmune disease with different clinical subtypes including cutaneous LP (CLP) and oral LP (OLP). We aimed to compare mRNA expression of RORγt and IL-17 in paraffin-embedded blocks of OLP and CLP lesions with normal oral mucosa (NOM), and also its correlation with hematologic parameters.

MATERIALS & METHODS

This study included 89 paraffin-embedded blocks contain OLP (44 cases), CLP (45 cases) and NOM from the archive of Mashhad University of Medical Sciences, Mashhad, Iran. The expression of RORγt and IL-17 was evaluated by Real-time RT-PCR method. The result was compared to Leukocyte counts and the other hematological parameters of studied patients.

RESULTS

The results of our study showed IL-17 and RORγt expression in OLP lesions were significantly higher than CLP and NOM groups (P = 0.001). Although we found high expression of RORγt and IL-17 in erosive OLP in compared to classic OLP lesion, but this increment was not significant for IL-17 (P = 0.26) and RORγt (P = 0.14). Further, Leukocyte and monocyte counts were substantially high in OLP group in compared to the CLP and NOM groups (P < 0.05).

CONCLUSIONS

We concluded that increased expression of RORγt and IL-17 in LP lesions could play role in the pathogenesis of LP. As well, higher expression of RORγt and IL-17 in oral LP more than cutaneous LP might be associated with difference in clinical behavior of the two types of disease and role of these factors in premalignant behavior of OLP lesions.

Effects of crystalline penicillin G sodium on human T-cells differentiation

Background

Although antibiotics are well-known for their anti-bacterial effects, their inaugurated immunomodulatory roles in chronic inflammatory diseases have not elucidated yet. Anecdotal reports support the beneficial effects of parenteral penicillin in arthritis suggesting an immunomodulatory other than antibacterial effects for penicillin. The present study was designed to address the possible effects of penicillin G sodium (PCN-G) on different T-helper cells differentiation.

Materials and Methods

In this experimental study, peripheral blood mononuclear cells (PBMCs) of 10 healthy donors were isolated using Ficoll density gradient. The stimulated PBMCs by anti-CD3, anti-CD28, and anti-CD69 were cultured in the presence of 120 μg/ml of PCN-G. Foxp3, T-bet, RORγT, GATA3 as well as interferon-gamma (IFN-γ) and interleukin (IL)-17A mRNA in stimulated cells were measured by the real-time polymerase chain reaction. Mann-Whitney U-test was used for determining differences between the medium of gene expression levels of stimulated cell population and unstimulated cells by PCN. Correlations between the related genes were determined using the Spearman test.

Results

Based on the results, T-bet gene expression levels were similar in stimulated cells by PCN G after 24 and 48 h while significant reduction was observed after 72 incubation with PCN G (difference = 3; 0.09-0.34; P = 0.031). Meanwhile, treated cells with PCN G expressed decreased levels of IFN-γ (difference = 8.0; 0.49-1.07; P = 0.001) and IL-17A (difference = 2.2; 0.05-0.75; P ≤ 0.05) genes comparing to unstimulated cell by PCN-G. GATA3 genes expression levels downregulated by PCN G after 72 h of incubation by PBMCs (difference = 1.1; 0.77-0.88; P = 0.035).

Conclusion

Our results confirmed the immunomodulatory role of PCN G by affecting the expression of different cytokines genes in PBMCs.