表观遗传读码器 BRD4 通过共同调节宿主脂噬作用和血管生成来支持分枝杆菌发病机制。

Epigenetic reader BRD4 supports mycobacterial pathogenesis by co-modulating host lipophagy and angiogenesis.

机构信息

Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India.

Centre for Infectious Disease Research, Indian Institute of Science, Bengaluru, India.

出版信息

Autophagy. 2022 Feb;18(2):391-408. doi: 10.1080/15548627.2021.1936355. Epub 2021 Jun 28.

Abstract

(Mtb)-driven lipid accumulation is intricately associated with the progression of tuberculosis (TB) disease. Although several studies elucidating the mechanisms for lipid droplet (LD) biosynthesis exist, we provide evidence for the significance of their regulated turnover via macroautophagy/autophagy during Mtb infection. We demonstrate that Mtb utilizes EGFR (epidermal growth factor receptor) signaling to induce the expression of the histone acetylation reader, BRD4 (bromodomain containing 4). The EGFR-BRD4 axis suppresses lipid-specific autophagy, and hence favors cellular lipid accumulation. Specifically, we found that pharmacological inhibition or knockdown of or enhances autophagic flux and concomitantly decreases cellular LDs that is otherwise maintained at a significant level in chloroquine-treated or knocked down autophagy-compromised host cells. In line with the enhanced lipophagy, we found that loss of EGFR or BRD4 function restricts mycobacterial burden that is rescued by external replenishment with oleic acid. We also report that the EGFR-BRD4 axis exerts additional effects by modulating pro-angiogenic gene expression and consequently aberrant angiogenesis during mycobacterial infection. This is important in the context of systemic Mtb dissemination as well as for the efficient delivery of anti-mycobacterial therapeutics to the Mtb-rich core of TB granuloma. Finally, utilizing an mouse model of TB, we show that pharmacological inhibition of EGFR and BRD4 compromises LD buildup via enhanced lipophagy and normalizes angiogenesis, thereby restricting Mtb burden and rescuing mice from severe TB-like pathology. These findings shed light on the novel roles of BRD4 during Mtb infection, and its possible implication in potentiating anti-TB responses.: ATG5: autophagy related 5; BRDs: bromodomain containing; COL18A1: collagen type XVIII alpha 1 chain; EGFR: epidermal growth factor receptor; EP300: E1A binding protein p300; KDR: kinase insert domain receptor; KLF5: Kruppel like factor 5; LDs: lipid droplets; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; Mtb: ; PECAM1: platelet and endothelial cell adhesion molecule 1; SQSTM1/p62: sequestosome 1; TB: tuberculosis; THBS1: thrombospondin 1; VEGF: vascular endothelial growth factor.

摘要

(Mtb)-驱动的脂质积累与结核病 (TB) 疾病的进展密切相关。尽管已经有几项研究阐明了脂滴 (LD) 生物合成的机制,但我们提供了证据表明,在 Mtb 感染过程中,通过巨自噬/自噬来调节它们的周转是很重要的。我们证明 Mtb 利用表皮生长因子受体 (EGFR) 信号诱导组蛋白乙酰化阅读器 BRD4 (包含溴结构域 4) 的表达。EGFR-BRD4 轴抑制脂质特异性自噬,从而有利于细胞脂质积累。具体来说,我们发现药理抑制或敲低 或 增强自噬通量,并同时减少细胞 LD,否则在氯喹处理或自噬受损的宿主细胞中,细胞 LD 会维持在显著水平。与增强的脂自噬一致,我们发现 EGFR 或 BRD4 功能的丧失限制了分枝杆菌的负担,而用油酸外部补充可以挽救这种负担。我们还报告说,EGFR-BRD4 轴通过调节促血管生成基因的表达来发挥额外的作用,从而导致分枝杆菌感染期间异常的血管生成。这在系统 Mtb 传播以及将抗分枝杆菌治疗药物有效递送至 TB 肉芽肿的 Mtb 丰富核心中很重要。最后,利用 Mtb 感染的 小鼠模型,我们表明,EGFR 和 BRD4 的药理抑制通过增强的脂自噬来损害 LD 的积累,并使血管生成正常化,从而限制 Mtb 的负担并使小鼠免于严重的类似 TB 的病理。这些发现揭示了 BRD4 在 Mtb 感染期间的新作用及其在增强抗 TB 反应中的可能作用。: ATG5: 自噬相关 5; BRDs: 溴结构域包含; COL18A1: 胶原 XVIII 阿尔法 1 链; EGFR: 表皮生长因子受体; EP300: E1A 结合蛋白 p300; KDR: 激酶插入结构域受体; KLF5: Kruppel 样因子 5; LDs: 脂滴; MAP1LC3B: 微管相关蛋白 1 轻链 3 beta; Mtb: ; PECAM1: 血小板和内皮细胞粘附分子 1; SQSTM1/p62: 自噬体相关蛋白 1; TB: 结核病; THBS1: 血栓素 1; VEGF: 血管内皮生长因子。

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