Microglia and macrophages in glioblastoma: landscapes and treatment directions

Area of Science:

• Neuro-oncology
• Immunology
• Cell Biology

Background:

• Glioblastoma is a highly aggressive primary brain tumor with poor prognosis.
• Tumor-associated macrophages (TAMs), including microglia and bone marrow-derived macrophages (BMDMs), play a critical role in glioblastoma's immune microenvironment.
• Current immunotherapies are ineffective in glioblastoma due to its 'immune-cold' nature and the predominance of immune-suppressive TAM states.

Purpose of the Study:

• To characterize the ontogeny and diverse cell states of TAMs in glioblastoma.
• To refine TAM classification using advanced single-cell and spatial multi-omic profiling.
• To inform improved therapeutic strategies targeting TAMs for glioblastoma treatment.

Main Methods:

• Single-cell and spatial multi-omic in situ profiling techniques.
• Analysis of TAM cell states in hypoxic/necrotic tumor cores and invasive margins.
• Investigating microglia and BMDM contributions to the glioblastoma immune landscape.

Main Results:

• TAMs in glioblastoma exhibit distinct cell states, with immune-suppressive phenotypes enriched in tumor cores.
• Pro-inflammatory and interferon signatures are associated with microglia at the invasive tumor margin.
• Understanding TAM heterogeneity is crucial for predicting their function.

Conclusions:

• Effective glioblastoma immunotherapy requires a deeper understanding of TAM biology and heterogeneity.
• Targeting TAMs, through depletion or repolarization, presents a promising therapeutic avenue.
• Advanced multi-omic profiling is essential for classifying TAM states and guiding treatment strategies.