The Tanyu Tongzhi Formula enhances IL-10 expression and macrophage efferocytosis to alleviate atherosclerosis in mice

BACKGROUND: Traditional Chinese Medicine (TCM), a significant subdiscipline within the realm of complementary medicine, has witnessed a surge in popularity across both Asian and Western nations over the past few decades. It holds potential as an adjunctive therapy for the management of atherosclerotic cardiovascular disease (ACVD). Tanyu Tongzhi Formula (TTF) -a TCM formula with decades of clinical application-has been demonstrated through completed randomized, controlled multicenter clinical studies to extend the maximum exercise duration in patients with chronic coronary syndrome and ameliorate TCM syndromes. TTF emerges as a promising therapeutic candidate for coronary artery disease characterized by phlegm stasis interaction. Additionally, TTF has demonstrated efficacy in protecting against atherosclerosis in murine models. However, the mechanisms by which TTF modulates macrophage function in atherosclerosis remain to be elucidated. PURPOSE: To investigate IL-10-dependent efferocytosis regulation as a pivotal mechanism underlying TTF's modulation of macrophage function in atherosclerosis. STUDY DESIGN AND METHODS: Low-density lipoprotein receptor or Apolipoprotein E null mice were subjected to a western diet for 8 weeks to induce atherosclerosis, after which they received TTF treatment for an additional 12 weeks. RNA sequencing was employed to identify interleukin-10 (IL-10) as a key downstream molecule. To verify the role of IL-10 in mediating the effects of TTF in reducing atherosclerosis, macrophage-specific IL-10 knockout mice were used. RESULTS: TTF administration significantly alleviated atherosclerosis in mice, evidenced by a reduction in atherosclerotic lesions and plaque necrosis, alongside an augmentation in collagen content. RNA sequencing revealed a substantial upregulation of IL-10 following TTF treatment, which corroborated in various macrophage populations and within mouse atherosclerotic plaques. IL-10 plays a crucial role in mediating the effects of TTF by enhancing macrophage efferocytosis. Notably, the targeted deletion of IL-10 in macrophages attenuated the therapeutic efficacy of TTF in mouse models of atherosclerosis. Furthermore, TTF activated the NF-κB pathway, leading to increased IL-10 expression. Trichosanthes kirilowii and Acorus tatarinowii were identified as the two functional components in TTF. CONCLUSION: IL-10-mediated efferocytosis potentiation is the critical pathway through which TTF stabilizes atherosclerotic plaques. The NF-κB/IL-10/efferocytosis axis provides a novel pharmacological target for macrophage-directed anti-atherosclerotic therapies. Tanyu Tongzhi Formula participates in the above regulatory mechanism and significantly alleviates atherosclerosis.