XthA phospholipase contributes the cell-wall functionality of pathogenic mycobacteria by increasing the synthesis of mycolic acid

Yanyan Jiang; Xinxin Zang; Tingting Feng; Hui Wang; Ning Cui; Yifan Duan; Chunwen Chen; Zhenjun Zhang; Ruonan Guo; Yunjie Gao; Yingying Cui; Guanghui Dang; Siguo Liu

doi:10.1016/j.ijbiomac.2025.145519

XthA phospholipase contributes the cell-wall functionality of pathogenic mycobacteria by increasing the synthesis of mycolic acid

Int J Biol Macromol. 2025 Jun 24;319(Pt 2):145519. doi: 10.1016/j.ijbiomac.2025.145519. Online ahead of print.

Authors

Affiliations

¹ State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin, Heilongjiang 150069, PR China.
² State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin, Heilongjiang 150069, PR China; Key Laboratory of Applied Technology on Green-Eco-Healthy Animal Husbandry of Zhejiang Province, Zhejiang Provincial Engineering Laboratory for Animal Health Inspection & Internet Technology, Zhejiang International Science and Technology Cooperation Base for Veterinary Medicine and Health Management, China-Australia Joint Laboratory for Animal Health Big Data Analytics, College of Animal Science and Technology & College of Veterinary Medicine of Zhejiang A&F University, Hangzhou, Zhejiang 311300, PR China.
³ State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin, Heilongjiang 150069, PR China; Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai 200240, PR China. Electronic address: dangguanghui@caas.cn.
⁴ State Key Laboratory for Animal Disease Control and Prevention, Division of Bacterial Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 678 Haping Street, Harbin, Heilongjiang 150069, PR China. Electronic address: liusiguo@caas.cn.

PMID: 40571004
DOI: 10.1016/j.ijbiomac.2025.145519

Abstract

The mycobacterial cell wall is a complex structure that plays a critical role in resisting external environmental stress and contributing to pathogenesis, with mycolic acid being a key component in maintaining cell wall integrity. Moreover, the enzymes involved in cell wall synthesis are frequently targeted in antimycobacterial drug research. In this study, we demonstrate that the conserved extracellular DNase XthA from mycobacteria exhibits phospholipase A₁ (PLA₁) activity, whereas this activity is absent in non-pathogenic mycobacteria. Moreover, XthA PLA₁ activity facilitates the formation of cord-like structures, promotes the proliferation of mycobacteria, and enhances their resistance to environmental stressors. Results from ethidium bromide and minimum inhibitory concentration assays suggest that XthA PLA₁ activity reduces the permeability of the mycobacterial cell wall. Furthermore, analyses using scanning electron microscopy and mass spectrometry demonstrated that PLA₁ activity contributes to cell wall integrity and enhances the synthesis of mycolic acids. Additionally, qPCR analysis indicated that XthA PLA₁ activity upregulates the transcript of key genes involved in the MAs synthesis pathway. Collectively, these findings suggest that pathogenic mycobacteria utilize XthA PLA₁ to facilitate cell wall functionality by regulating mycolic acid synthesis, thereby underscoring its potential as a drug target for disrupting the cell wall of pathogenic mycobacteria.

Keywords: Cell wall; Mycobacterial phospholipase; Mycolic acid.