Self-assembled DNA nanostructures for the immunomodulation of microglia in neuroinflammation

Neurodegenerative diseases are closely associated with neuroinflammation. Although neuroinflammation alone cannot fully explain the onset and progression of these disorders, it represents a significant component of their etiology, alongside factors such as genetic susceptibility. Under pathological stimulation, microglia undergo a morphological and functional transformation, shifting from a homeostatic state (M0) to an activated, pro-inflammatory phenotype (M1). This activation is accompanied by increased production of inflammatory mediators and is partly regulated by changes in microRNA (miRNA) expression such as miR-34a and miR-155, which contribute to the amplification and propagation of inflammatory signaling within the central nervous system. In this thesis, we aimed to develop a DNAzyme-containing DNA nanostructure designed to selectively cleave a pro-inflammatory miRNA implicated in microglial activation. The hypothesis was that targeted degradation of this miRNA could attenuate inflammatory signaling pathways and thereby reduce neuroinflammation. To evaluate this approach, we characterized the effect of the DNA nanostructure on the levels of the target miRNA, as well as on the expression of key messenger RNA (mRNA) markers associated with inflammation. These markers included genes typically upregulated during microglial activation and indicative of a pro-inflammatory state. Despite observing measurable interactions between the nanostructure and the molecular targets, the overall results did not provide sufficient significative evidence to conclusively demonstrate a significant anti-inflammatory effect. Based on the criteria assessed, we cannot definitively affirm that the DNAzyme-containing nanostructure effectively reduces neuroinflammation under the tested conditions.