Lingguizhugan decoction inhibit pulmonary hypertension by regulating macrophage IL-6 secretion via IL-33/ST2 pathway

Lingguizhugan decoction (LGZG), a typical Chinese herbal formula, has remarkable clinical effects for treating pulmonary hypertension (PH) with unclear ingredients and mechanisms. This study aimed to evaluate the efficacy of LGZG and the mechanism of its active ingredients in treating PH.

The PH patient phenotype was characterized by transcriptomic assay of peripheral blood mononuclear cells (PBMCs) and multiplex cytokine profiling of serum. The active ingredients of LGZG were identified by UPLC-Q-TOF-MS. The monocrotaline (MCT)-induced PH model was performed to evaluate the effects of LGZG and its active ingredients in vivo. The interleukin-33 (IL-33)-induced RAW264.7 cells and the mouse pulmonary artery smooth muscle cells (mPASMCs) were applied to explored phenotype and mechanism of the active ingredients of LGZG by immunofluorescence, western blotting and RT-qPCR in vitro.

Inflammatory receptor activity in PBMCs and serum interleukin-6 (IL-6) levels were elevated in PH patients. Porinic acid B, cinnamic acid, atractylenolide I and glycyrrhizin (PCAG) were characterized and combined to treat the PH, And the IL-33/Growth stimulation expressed gene 2 (ST2) pathway may be the potential mechanism by transcriptomic analysis of lung tissues. Both in vivo and in vitro experiments confirmed that PCAG inhibited the IL-33/ST2 pathway, reduced macrophage polarization, and suppressed IL-6 secretion. Moreover, ST2 overexpression in macrophages attenuated the inhibitory effect of PCAG. Using a co-culture system of macrophages and mPASMCs, we demonstrated that PCAG reduced mPASMCs phenotypic switching by suppressing macrophage-derived IL-6 secretion.

The active ingredient of LGZG, PCAG, inhibits the progression of PH by preventing macrophage polarization and IL-6 secretion through the IL-33/ST2 pathway.