Multiple sclerosis (MS) is an autoimmune disease characterized by inflammatory infiltration and demyelination in the central nervous system (CNS). IFN‐gamma (IFN‐γ), a critically important immunomodulator, has been widely studied in MS pathology. The confusing and complex effects of IFN‐γ in MS patients and rodent models, however, cause us to look more closely at its exact role in MS. In this study, we identified the role of the IFN‐γ signaling in the choroid plexus (CP) in the experimental autoimmune encephalomyelitis (EAE) model. We found that the IFN‐γ signal was rapidly amplified when CNS immune cell infiltration occurred in the CP during the progressive stage. Furthermore, using two CP‐specific knockdown strategies, we demonstrated that blocking the IFN‐γ signal via knockdown of IFN‐γR1 in the CP could protect mice against EAE pathology, as evidenced by improvements in clinical scores and infiltration. Notably, knocking down IFN‐γR1 in the CP reduced the local expression of adhesion molecules and chemokines. This finding suggests that IFN‐γ signaling in the CP may participate in the pathological process of EAE by preventing pathological T helper (Th) 17 ⁺ cells from infiltrating into the CNS. Finally, we showed that the unbalanced state of IFN‐γ signaling between peripheral lymphocytes and the choroid plexus may determine whether IFN‐γ has a protective or aggravating effect on EAE pathology. Above all, we discovered that IFN‐γR1‐mediated IFN‐γ signaling in the CP was a vital pathway in the pathological process of EAE.

Hydrocephalus is a common and serious neuropathological condition characterized by disrupted cerebrospinal fluid (CSF) circulation, which lacks effective pharmacotherapy. Here, we demonstrate that adenosine A_2A receptor (A_2AR) signaling in the choroid plexus (ChP) is a trigger of hydrocephalus. Adenosine levels are increased in the CSF of hydrocephalus patients and mice, together with elevated ChP-A_2AR density. Accordingly, continued infusion of adenosine for 14 days or transgenic ChP-A_2AR overexpression is sufficient to drive CSF hypersecretion and ventriculomegaly. Conversely, selective knockdown of ChP-A_2AR reduces CSF production and ameliorates CSF hypersecretion and ventriculomegaly induced by autologous blood and kaolin. Furthermore, we unveil ChP-A_2AR signaling as a molecular mechanism linking brain insults with CSF hypersecretion through parallel PI3K/Akt-dependent activation of SPAK phosphorylation and NF-κB-dependent transcriptional regulation of ATP1A2. Lastly, the A_2AR antagonist KW6002 protects against hydrocephalus induced by autologous blood and kaolin, offering a novel treatment for hydrocephalus by repurposing the FDA-approved A_2AR antagonist istradefylline.

The considerable abundance and remarkable stability of sEVs provide substantial benefits for diagnosing Alzheimer's disease. Therefore, precise tracking subtypes of small extracellular vesicles (sEVs) is crucial for screening novel diagnostic biomarkers and developing therapeutic technologies. We propose a three-target recognition-mediated proximity ligation assay for the precise identification of sEV subtypes utilizing three specifically designed probes: one for the exosomal surface protein CD63 recognition, one for fixing the biolipid layer, and the third for the identification of distinctive protein associated with a specific subtype of sEVs (L1CAM positive sEVs). The developed sEVs subtype tracing approach integrates proximity ligation of the three probes to specifically bind to surface biomarkers and polymerase chain reaction (PCR) for signal amplification, enabling "AND" logic analysis of three essential components on sEVs. This method can be utilized for both sEVs quantification and subtype tracing. The proposed approach demonstrated a low limit of detection for neuronal sEVs at 2.5 particles/μL, according to this design. In addition, we utilized this technique to measure plasma sEV levels in individuals with Alzheimer's disease and examined its early diagnostic effectiveness. The approach can assess the concentration ratios of neuronal sEVs and cancer-derived sEVs, highlighting its potential for clinical applications. In addition, the approach enables precise tracing and identification of sEVs subtypes, hence facilitating extensive applications in biological science, biomedical engineering, and personalized medicine.