Proust Alizé, Wilkinson Katalin A, Wilkinson Robert J
The Francis Crick Institute, Midland Road, London, NW1 1AT, UK.
Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, Department of Medicine, University of Cape Town, Observatory, 7925, Republic of South Africa.
J Neuroinflammation. 2025 May 26;22(1):141. doi: 10.1186/s12974-025-03467-7.
Tuberculous meningitis is the most severe form of tuberculosis and HIV-1 co-infection worsens the already poor prognosis. However, how Mycobacterium tuberculosis crosses the blood-brain barrier and how HIV-1 influences tuberculous meningitis pathogenesis remains unclear.
Using human pericytes, astrocytes, endothelial cells, and microglia alone and combined in an in vitro blood-brain barrier model, we investigated the effect of Mycobacterium tuberculosis +/- HIV-1 co-infection on central nervous system cell entry and function. Cells and the blood-brain barrier model were infected with Mycobacterium tuberculosis and/or HIV-1 and we evaluated the effects of both infection on (i) cells susceptibility to Mycobacterium tuberculosis and its growth in cells by flow cytometry; (ii) modulation of blood-brain barrier permeability and Mycobacterium tuberculosis passage through it; (iii) viral and bacterial cytopathogenicity using the xCELLigence system; (iv) cell metabolic activity and ROS release using colorimetric assays; (v) extracellular glutamate concentration by fluorometric assay; (vi) the inflammatory response by Luminex; and (vii) endoplasmic reticulum stress by quantitative PCR.
We demonstrated that Mycobacterium tuberculosis infects and multiplies in all cell types with HIV-1 increasing entry to astrocytes and pericytes, and growth in HIV-1 positive pericytes and endothelial cells. Mycobacterium tuberculosis also induces an increase of the blood-brain barrier permeability resulting in translocation of bacilli across it. Cytopathic effects include (i) increased markers of cellular stress (mitochondrial metabolic activity, unfolded protein response); (ii) ROS release; (iii) the induction of neurotoxic astrocytes; (iv) and the secretion of the excitotoxic neurotransmitter glutamate. Lastly, we observed distinct cell-type specific production of inflammatory and effector mediators.
These results indicate that Mycobacterium tuberculosis can translocate the blood-brain barrier directly to initiate meningitis.
结核性脑膜炎是结核病最严重的形式，而HIV-1合并感染会使本就不佳的预后更加恶化。然而，结核分枝杆菌如何穿过血脑屏障以及HIV-1如何影响结核性脑膜炎的发病机制仍不清楚。
我们使用人周细胞、星形胶质细胞、内皮细胞和小胶质细胞单独及组合构建体外血脑屏障模型，研究结核分枝杆菌±HIV-1合并感染对中枢神经系统细胞进入和功能的影响。细胞和血脑屏障模型用结核分枝杆菌和/或HIV-1感染，我们评估两种感染对以下方面的影响：(i)细胞对结核分枝杆菌的易感性及其在细胞内的生长，通过流式细胞术检测；(ii)血脑屏障通透性的调节以及结核分枝杆菌通过血脑屏障的情况；(iii)使用xCELLigence系统检测病毒和细菌的细胞致病性；(iv)使用比色法检测细胞代谢活性和活性氧释放；(v)通过荧光法检测细胞外谷氨酸浓度；(vi)使用Luminex检测炎症反应；(vii)通过定量PCR检测内质网应激。
我们证明结核分枝杆菌可感染所有细胞类型并在其中繁殖，HIV-1增加了结核分枝杆菌进入星形胶质细胞和周细胞的能力，并在HIV-1阳性周细胞和内皮细胞中生长。结核分枝杆菌还会导致血脑屏障通透性增加，使杆菌能够穿过血脑屏障。细胞病变效应包括：(i)细胞应激标志物增加（线粒体代谢活性、未折叠蛋白反应）；(ii)活性氧释放；(iii)诱导神经毒性星形胶质细胞；(iv)分泌兴奋性神经递质谷氨酸。最后，我们观察到炎症和效应介质在不同细胞类型中有特异性产生。
这些结果表明结核分枝杆菌可直接穿过血脑屏障引发脑膜炎。
