2. Academic Validation
  3. Saikosaponin A targets HDAC6 to inhibit Mycobacterium tuberculosis-induced macrophage Pyroptosis via autophagy-mediated NLRP3 inflammasome inactivation

Saikosaponin A targets HDAC6 to inhibit Mycobacterium tuberculosis-induced macrophage Pyroptosis via autophagy-mediated NLRP3 inflammasome inactivation

  • Phytomedicine. 2025 Jul:142:156693. doi: 10.1016/j.phymed.2025.156693.
Fanglin Liu 1,  Jianchao Wu 1,  Jingjing Shen 1,  Hemin Zhang 1,  Yaqi Liu 1,  Jinxia Sun 1,  Yuejuan Zheng 2,  Xin Jiang 3
Affiliations

Affiliations

  • 1 Department of Immunology and Pathogenic Biology, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China.
  • 2 The Research Center for Traditional Chinese Medicine, Shanghai Institute of Infectious Diseases and Biosecurity, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, PR China; School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China. Electronic address: 13641776412@163.com.
  • 3 Department of Immunology and Pathogenic Biology, School of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, PR China; The Research Center for Traditional Chinese Medicine, Shanghai Institute of Infectious Diseases and Biosecurity, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, PR China; Shanghai Key Laboratory of Health Identification and Assessment, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, PR China. Electronic address: jiangxingao@163.com.
PMID: 40393213 DOI: 10.1016/j.phymed.2025.156693
Abstract

Background: Mycobacterium tuberculosis (Mtb) is among the oldest and most resilient human pathogens, remaining a major global public health threat. Its characteristic pathological features include granuloma formation and a systemic inflammatory response, primarily resulting from dysregulated host immune reactions. Therefore, host-directed therapy (HDT) is considered an important complement to conventional anti-TB treatment.

Purpose: This study sought to examine the inhibitory effects of Saikosaponin A (SSA), an active compound extracted from Bupleurum, on Mtb-induced macrophage Pyroptosis, as well as the underlying molecular mechanisms.

Methods: The effects of SSA on key molecules involved in Pyroptosis and Autophagy were examined in an in vitro model of Mtb-infected macrophages using Western blotting, ELISA, co-immunoprecipitation, and immunofluorescence assays. The function of histone deacetylase 6 (HDAC6) in modulating Autophagy and Pyroptosis in Mtb-infected macrophages was elucidated using gene silencing techniques. The SSA-HDAC6 interaction was validated using drug target identification methods such as molecular docking and site-directed mutagenesis. Furthermore, we established an in vivo model of lipopolysaccharide-induced pulmonary inflammation via intraperitoneal injection to assess whether SSA exerts a protective effect by inhibiting Pyroptosis.

Results: In vitro experiments demonstrated that SSA enhanced Autophagy to inactivate the NLRP3 inflammasome, thereby inhibiting Mtb-induced Pyroptosis. Mechanistically, SSA interacted with HDAC6 and effectively suppressed its enzymatic activity. This interaction enabled SSA to target HDAC6, thereby modulating Autophagy via the AMPK/mTOR/ULK1 axis, ultimately attenuating Mtb-induced Pyroptosis in macrophages. Furthermore, in vivo experiments revealed that SSA regulated the acetylation of α-tubulin (Lys40), alleviating inflammatory lung injury in mice.

Conclusion: SSA targets HDAC6 and exerts an immunomodulatory effect, highlighting its potential as a promising novel host-directed anti-tuberculosis agent.

Keywords

Autophagy; HDAC6; Host-directed therapy; Mycobacterium tuberculosis; Pyroptosis; Saikosaponin A.

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