Innate Immune Receptor NLRX1: Potential Modulator of Glioblastoma Pathophysiology

Gliomas are primary brain tumors that develop from glial cells within the central nervous system and are among the deadliest human cancers. Glioblastoma (GBM) is the most malignant form of glioma. NLRX1 is an innate immune pattern recognition receptor that exhibits tumor-suppressive and tumor-promoting effects that may be cancer or cell-type, context-dependent, aided by differences in the microenvironment. Here, we report that NLRX1 is differentially expressed in microglia, astrocytes, GBM cell lines, and glioma patient tissues. siRNA-mediated silencing of Nlrx1 decreases the ability of the GBM cell line, LN-229, to proliferate and migrate. Nlrx1 ^-/- GBM cells exhibit attenuated ability to generate 3D spheroids and enhanced capability to form tunneling nanotubes. Moreover, Nlrx1 ^-/- GBM cells show decreased expression of autophagy markers, suggesting that NLRX1 plays a role in maintaining autophagy in GBM. In summary, our findings indicate that NLRX1 may modulate GBM pathophysiology by regulating GBM cell proliferation, migration, and metabolism. We believe our understanding of NLRX1 in GBM pathophysiology paves the potential development of GBM-targeting therapeutics that may delay disease progression and/or improve survival.