Telmisartan, an angiotensin II receptor blocker, attenuates Prevotella intermedia lipopolysaccharide-induced production of nitric oxide and interleukin-1β in murine macrophages.

Telmisartan, widely prescribed for the treatment of hypertension, has an anti-inflammatory property in addition to being an angiotensin II type 1 receptor antagonist. This study was carried out to explore the influence of telmisartan upon the elaboration of inflammatory mediators in murine macrophages stimulated with lipopolysaccharide (LPS) prepared from Prevotella intermedia, a periodontal pathogen, as well as its molecular mechanisms. Telmisartan significantly inhibited LPS-induced generation of inducible nitric oxide (NO) synthase-derived NO and interleukin-1β (IL-1β) as well as their gene expressions in RAW264.7 cells. Telmisartan treatment of LPS-activated cells significantly up-regulated arginase 1 (Arg-1) and chitinase-like 3 (Ym-1), which are specific markers of M2 macrophages. Telmisartan caused a significant increase in heme oxygenase-1 (HO-1) expression in cells stimulated with LPS, and its inhibitory action against NO production was reversed by treatment with SnPP, an HO-1 inhibitor. Phosphorylation of STAT1 and STAT3 induced by LPS was attenuated by telmisartan. Telmisartan inhibited LPS-induced generation of NO and IL-1β independently of PPAR-γ activation. In addition, activation of NF-κB as well as JNK and p38 signaling induced by LPS was not modulated by telmisartan. In summary, telmisartan is a potent inhibitor of P. intermedia LPS-induced generation of NO and IL-1β in RAW264.7 cells and promotes macrophage phenotype switching toward the M2 phenotype. Telmisartan may have potential to be developed into host modulatory agent for inflammatory periodontal disease, although additional studies are needed to confirm the therapeutic effect.