MMPs and NETs are detrimental in CNS-tuberculosis with MMP inhibitor doxycycline improving murine CNS-tuberculosis survival (mouse)

Despite effective anti-tuberculous treatment (ATT), up to 40% of patients with central nervous system tuberculosis (CNS-TB) suffer permanent neurological deficits and death. Immunopathology in CNS-TB, characterized by extensive brain inflammation and tissue destruction, is driven by a matrix-degrading phenotype, which results from an increase in matrix metalloproteinases (MMPs) relative to their tissue-specific inhibitors (tissue inhibitor of metalloproteinases, TIMPs). The immunopathological mechanism of CNS-TB remains undefined, hindering the development of new CNS-TB therapies. By performing laser capture microdissection RNA sequencing (LCM-RNA Seq), we profiled the spatial transcriptome of murine CNS-TB (M.tb H37Rv-infected C57BL6 Nos2-/- mice) and healthy murine (C57BL6 Nos2-/- mice) as control. The granulomas from murine CNS-TB treated with ATT alone, ATT with SB-3CT (MMP-2/9-specific MMP inhibitor), and ATT with doxycycline (broad spectrium MMP-inhibitor) were also profiled. Genes implicated in defense, immune, inflammatory and cytokine responses, neutrophil degranulation, antigen presentation and Toll-Like Receptor cascades, present predominantly in CNS-TB granulomas relative to other tissue types. On the other hand, genes relate to trans-synaptic signaling, synapse and cell junction organisation, neuron development and differentiation had decreased expression in murine CNS-TB inflammatory and granuloma tissues. We also found an increased expression of genes involve in response to oxidative stress, apoptosis and programmed cell death in murine CNS-TB treated with ATT plus adjunctive MMP inhibitors. Overall design: Formalin-fixed paraffin-embedded (FFPE) brain tissues were processed from murine CNS-TB (n=4), healthy murine (n=4), murine CNS-TB treated with ATT (n=8), murine CNS-TB treated with ATT plus SB-3CT (n=8), and murine CNS-TB treated with ATT plus doxycycline (n=8). All tissue sections with 7 µm thickness each were stained with hematoxylin prior to LCM-RNA Seq. Target regions including granuloma, inflammatory region and adjacent normal regions were selected and microdissected for library construction. The libraries were sequenced and analysed.