Bikkasani, S. | Search bioRxiv

bioRxiv2026

Dendrimer Delivered shRNA Targeting the CCL20-CCR6 Axis Suppresses Complement-Mediated Microglial Synaptic Pruning and Ameliorates Chronic Neuroinflammation After Repetitive Traumatic Brain Injury

Repetitive traumatic brain injury (rTBI) induces persistent microglial activation and chronic neuroinflammation, yet the upstream signals driving long-term synaptic injury remain unclear. In this study, we identify the CCL20-CCR6 chemokine axis as a critical regulator of sustained microglial activation and complement-dependent synaptic loss after rTBI. Proteomic profiling at 30 days post-injury (dpi) showed broad normalization of complement-linked inflammatory and synaptic pathways in the cortex and hippocampus, underscoring a mechanistic link between chemokine signaling, microglial activation, and synaptic vulnerability. To therapeutically target this axis, we developed a dendrimer-based shRNA platform (shCombo-DPX) that simultaneously silences CCL20 and CCR6. Intranasal and intravenous delivery in rTBI mice effectively reduced CCL20-CCR6 expression, attenuated chronic microgliosis and astrogliosis, and suppressed complement activation. Treatment limited microglial synaptic engulfment, preserved synaptic proteins, restored BDNF levels, and improved motor, anxiety-related, and cognitive outcomes. In microglia-neuron coculture systems, CCL20 silencing reduced LPS-induced complement signaling and prevented synaptic loss, neuronal apoptosis, and BDNF depletion. Conversely, exposure to recombinant CCL20 induced dendritic degeneration, caspase-3 activation, microglial reactivity, complement dysregulation, and synaptic injury both in vitro and in vivo. Collectively, these findings establish CCL20-CCR6 as a key upstream driver of chronic complement-mediated synaptic degeneration after rTBI and support dendrimer-delivered shRNA therapy as a targeted strategy to mitigate long-term neurodegeneration.

neuroscience↗

bioRxiv2026

CCL20-CCR6 Signaling as a Prognostic Biomarker and Therapeutic Target in Temozolomide-Resistant Glioblastoma

Glioblastoma remains highly lethal, with median survival of ~15 months. Resistance to temozolomide is ubiquitous, yet its mechanisms are incompletely understood. Here, we identify the CCL20-CCR6 chemokine axis as a stress-responsive survival pathway limiting therapeutic efficacy. Targeting CCL20-CCR6 in combination with temozolomide and cannabidiol was evaluated using clinical datasets, GBM cell lines, tumor organoids, and a syngeneic CT-2A mouse model integrating proteomic and lipidomic profiling. Low CCL20 expression was associated with improved survival, supporting its prognostic relevance. Across models, TMZ alone or with CBD induced CCL20 expression while exerting limited antitumor activity. Targeted disruption of CCL20-CCR6 signaling using dendrimer-delivered shRNA enhanced therapeutic response in murine models and GBM organoids. Multi-omic analyses revealed that CCL20 inhibition reprograms the tumor microenvironment and induces mitochondrial dysfunction, resulting in elevated reactive oxygen species (ROS) and tumor cell death. This effect was accompanied by accumulation of 17-hydroxydocosahexaenoic acid and activation of oxidative stress-associated cytotoxic pathways. Functional assays confirmed that CCL20 blockade selectively amplifies mitochondrial ROS beyond levels induced by TMZ alone potentiating TMZ efficacy by promoting mitochondrial oxidative stress. Targeting this axis represents a promising strategy to overcome chemoresistance and positions CCL20 as both a prognostic biomarker and a therapeutic vulnerability in GBM.

cancer biology↗