Neurons are host cells for Mycobacterium tuberculosis.

Area of Science:

• Neuroscience
• Infectious Diseases
• Microbiology

Background:

• Central nervous system (CNS) tuberculosis is initiated after Mycobacterium tuberculosis (M. tuberculosis) crosses the blood-brain barrier.
• M. tuberculosis is primarily phagocytosed by microglial cells within the CNS.

Purpose of the Study:

• To investigate the interactions between M. tuberculosis and neurons.
• To determine if neurons can serve as host cells for M. tuberculosis infection within the CNS.

Main Methods:

• In vitro studies using murine neuronal cell lines (HT22, Neuro-2a) and human neuronal cell line (SK-N-SH).
• In vitro studies using primary murine hippocampus-derived neuronal cultures.
• In vivo studies involving intracerebral challenge in C57BL/6 mice.

Main Results:

• Neurons internalized M. tuberculosis bacilli in a time-dependent manner.
• Internalized M. tuberculosis bacilli exhibited productive infection, with a 2- to 4-fold increase in viability and replication within 48 hours.
• M. tuberculosis infection of neurons was confirmed both in vitro and in vivo in mouse brains.

Conclusions:

• Neurons are identified as potential host cells for M. tuberculosis within the CNS.
• This finding suggests neurons may represent a novel target for M. tuberculosis in the central nervous system.
• The study expands the understanding of M. tuberculosis pathogenesis in the CNS beyond microglial cells.