Curcumin ameliorates traumatic brain injury via C1ql3-mediated microglia M2 polarization

Extracellular vesicles as carriers for noncoding RNA-based regulation of macrophage/microglia polarization: an emerging candidate regulator for lung and traumatic brain injuries

Macrophage/microglia function as immune defense and homeostatic cells that originate from bone marrow progenitor cells. Macrophage/microglia activation is historically divided into proinflammatory M1 or anti-inflammatory M2 states based on intracellular dynamics and protein production. The polarization of macrophages/microglia involves a pivotal impact in modulating the development of inflammatory disorders, namely lung and traumatic brain injuries. Recent evidence indicates shared signaling pathways in lung and traumatic brain injuries, regulated through non-coding RNAs (ncRNAs) loaded into extracellular vesicles (EVs). This packaging protects ncRNAs from degradation. These vesicles are subcellular components released through a paracellular mechanism, constituting a group of nanoparticles that involve exosomes, microvesicles, and apoptotic bodies. EVs are characterized by a double-layered membrane and are abound with proteins, nucleic acids, and other bioactive compounds. ncRNAs are RNA molecules with functional roles, despite their absence of coding capacity. They actively participate in the regulation of mRNA expression and function through various mechanisms. Recent studies pointed out that selective packaging of ncRNAs into EVs plays a role in modulating distinct facets of macrophage/microglia polarization, under conditions of lung and traumatic brain injuries. This study will explore the latest findings regarding the role of EVs in the progression of lung and traumatic brain injuries, with a specific focus on the involvement of ncRNAs within these vesicles. The conclusion of this review will emphasize the clinical opportunities presented by EV-ncRNAs, underscoring their potential functions as both biomarkers and targets for therapeutic interventions.

C1ql3 knockout affects microglia activation, neuronal integrity, and spontaneous behavior in Wistar rats

BACKGROUND

C1QL3 is widely expressed in the brain and is specifically produced by a subset of excitatory neurons. However, its function is still not clear. We established C1ql3-deficient rats to investigate the role of C1QL3 in the brain.

METHODS

C1ql3 knockout (KO) rats were generated using CRISPR/Cas9. C1ql3 KO was determined by polymerase chain reaction (PCR), DNA sequencing, and western blotting. Microglia morphology and cytokine expression with or without lipopolysaccharide (LPS) stimulus were analyzed using immunohistochemistry and real-time PCR. The brain structure changes in KO rats were examined using magnetic resonance imaging. Neuronal architecture alteration was analyzed by performing Golgi staining. Behavior was evaluated using the open field test, Morris water maze test, and Y maze test.

RESULTS

C1ql3 KO significantly increased the number of ramified microglia and decreased the number of hypertrophic microglia, whereas C1ql3 KO did not influence the expression of pro-inflammatory factors and anti-inflammatory factors except IL-10. C1ql3 KO brains had more amoeboid microglia types and higher Arg-1 expression compared with the WT rats after LPS stimulation. The brain weights and HPC sizes of C1ql3 KO rats did not differ from WT rats. C1ql3 KO damaged neuronal integrity including neuron dendritic arbors and spine density. C1ql3 KO rats demonstrated an increase in spontaneous activity and an impairment in short working memory.

CONCLUSIONS

C1ql3 KO not only interrupts the neuronal integrity but also affects the microglial activation, resulting in hyperactive behavior and impaired short memory in rats, which highlights the role of C1QL3 in the regulation of structure and function of both neuronal and microglial cells.

A highly bioavailable curcumin formulation ameliorates inflammation cytokines and neurotrophic factors in mice with traumatic brain injury

A novel curcumin formulation increases relative absorption by 46 times (CurcuWIN®) of the total curcuminoids over the unformulated standard curcumin form. However, the exact mechanisms by which curcumin demonstrates its neuroprotective effects are not fully understood. This study aimed to investigate the impact of a novel formulation of curcumin on the expression of brain-derived neurotrophic factor (BDNF), glial fibrillary acidic protein (GFAP), a main component of the glial scar and growth-associated protein-43 (GAP-43), a signaling molecule in traumatic brain injury (TBI). Mice (adult, male, C57BL/6j) were randomly divided into three groups as follows: TBI group (TBI-induced mice); TBI + CUR group (TBI mice were injected i.p. curcumin just after TBI); TBI+ CurcuWIN® group (TBI mice were injected i.p. CurcuWIN® just after TBI). Brain injury was induced using a cold injury model. Injured brain tissue was stained with Cresyl violet to evaluate infarct volume and brain swelling, analyzed, and measured using ImageJ by Bethesda (MD, USA). Western blot analysis was performed to determine the protein levels related to injury. While standard curcumin significantly reduced brain injury, CurcuWIN® showed an even greater reduction associated with reductions in glial activation, NF-κB, and the inflammatory cytokines IL-1β and IL-6. Additionally, both standard curcumin and CurcuWIN® led to increased BDNF, GAP-43, ICAM-1, and Nrf2 expression. Notably, CurcuWIN® enhanced their expression more than standard curcumin. This data suggests that highly bioavailable curcumin formulation has a beneficial effect on the traumatic brain in mice.