Role of Chicoric Acid and 13-Cis Retinoic Acid in Mycobacterium tuberculosis Infection Control by Human U937 Macrophage

Mycobacterium tuberculosis (Mtb) survives and proliferates within the main cells of the innate immune system, macrophages. The goal of our study was to investigate the immunostimulatory effects of 13-cis retinoic acid (RA) and chicoric acid (CA) in human U937 macrophages against H37Ra Mtb infection by evaluating its potential role in the cell surface expression of HLA-DR, CD14 molecules as well as nitric oxide (NO) production and prevention of the Mtb growth within macrophages. In this study, we investigated the effects of 13-cis RA and CA on Mtb-infected macrophages using flowcytometry and Griess methods, respectively. Moreover, inhibitory effect of 13-cis RA and CA on Mtb growth within macrophages were assessed using colony-forming unit. 13-Cis RA and CA enhanced the cell surface expression of HLA-DR and CD14 molecules on U937 macrophages and prevented the growth of Mtb within macrophages. In addition, 13-cis RA and CA, have increased NO generation compared to untreated control macrophages, significantly (p < 0.001). Both drugs have a significant inhibitory effect on Mtb growth but CA at the highest concentration was more potent than 13-cis RA (p < 0.05). The results of our study showed that infected U937 macrophages treated with 13-cis RA and CA represented significant increases in NO production, CD14 and HLA-DR expression and also prevents intracellular survival of Mtb. Therefore, 13-cis RA and CA may have a significant therapeutic approach in the control of Mtb infection.