Expression of Toll-like receptors in the cerebellum during pathogenesis of prion disease.

Prion diseases, such as scrapie, entail the accumulation of disease-specific prion protein (PrPSc) within the brain. Toll-like receptors (TLRs) are crucial components of the pattern recognition system. They recognize pathogen-associated molecular patterns (PAMPs) and play a central role in orchestrating host innate immune responses. The expression levels of Toll-like receptors (TLRs) in the central nervous system (CNS) were not well-defined. To establish a model of prion diseases in BALB/C mice, the 22L strain was employed. The features of the 22L strain were analyzed, and the cerebellum exhibited severe pathological changes. TLR1-13 levels in the cerebellum were measured using quantitative polymerase chain reaction (qPCR) at time points of 60, 90, 120, and the final end point (145 days post-infection). During the pathogenesis, the expression levels of Toll-like receptors (TLRs) 1, 2, 7, 8, and 9 increased in a time-dependent manner. This trend mirrored the expression patterns of PrPSc (the pathological isoform of the prion protein) and glial fibrillary acidic protein. Notably, at the end point, TLR1-13 levels were significantly elevated. Protein level of TLR7 and TLR9 showed increasing at the end point of the 22L-infected mice. A deeper understanding of the increased Toll-like receptors (TLRs) in prion diseases could shed light on their role in initiating immune responses at various stages during pathogenesis. This insight is particularly relevant when considering TLRs as potential therapeutic targets for prion diseases.

Acacetin inhibits activation of microglia to improve neuroinflammation after subarachnoid hemorrhage through the PERK signaling pathway mediated autophagy.

PURPOSE: To explore the effect of acacetin on subarachnoid hemorrhage (SAH) and its possible mechanism. METHODS: SAH model of rat was established, and intraperitoneally injected with three doses of acacetin. To verify the role of PERK pathway, we used the CCT020312 (PERK inhibitor) and Tunicamycin (activators of endoplasmic reticulum stress). The SAH score, neurological function score, brain edema content, and Evans blue (EB) exudate were evaluated. Western blot was used to determine the expression of inflammation-associated proteins and PERK pathway. The activation of microglia was also determined through Iba-1 detection. TEM and immunofluorescence staining of LC3B were performed to observe the autophagy degree of SAH rats after acacetin. Tunel/NeuN staining, HE and Nissl' staining were performed for neuronal damage. RESULTS: Acacetin increased the neurological function score, reduce brain water content, Evans blue exudation and SAH scores. The microglia in cerebral cortex were activated after SAH, while acacetin could inhibit its activation, and decreased the expression of TNF-α and IL-6 proteins. The pathological staining showed the severe neuronal damage and increased neuronal apoptosis after SAH, while acacetin could improve these pathological changes. We also visualized the alleviated autophagy after acacetin. The expression of Beclin1 and ATF4 proteins were increased, but acacetin could inhibit them. Acacetin also inactivated PERK pathway, which could improve the neuronal injury and neuroinflammation after SAH, inhibit the microglia activation and the overactivated autophagy through PERK pathway. CONCLUSION: Acacetin may alleviate neuroinflammation and neuronal damage through PERK pathway, thus having the protective effect on EBI after SAH.

Prediction of clinical progression in nervous system diseases: plasma glial fibrillary acidic protein (GFAP).

Glial fibrillary acidic protein (GFAP), an intracellular type III intermediate filament protein, provides structural support and maintains the mechanical integrity of astrocytes. It is predominantly found in the astrocytes which are the most abundant subtypes of glial cells in the brain and spinal cord. As a marker protein of astrocytes, GFAP may exert a variety of physiological effects in neurological diseases. For example, previous published literatures showed that autoimmune GFAP astrocytopathy is an inflammatory disease of the central nervous system (CNS). Moreover, the studies of GFAP in brain tumors mainly focus on the predictive value of tumor volume. Furthermore, using biomarkers in the early setting will lead to a simplified and standardized way to estimate the poor outcome in traumatic brain injury (TBI) and ischemic stroke. Recently, observational studies revealed that cerebrospinal fluid (CSF) GFAP, as a valuable potential diagnostic biomarker for neurosyphilis, had a sensitivity of 76.60% and specificity of 85.56%. The reason plasma GFAP could serve as a promising biomarker for diagnosis and prediction of Alzheimer's disease (AD) is that it effectively distinguished AD dementia from multiple neurodegenerative diseases and predicted the individual risk of AD progression. In addition, GFAP can be helpful in differentiating relapsing-remitting multiple sclerosis (RRMS) versus progressive MS (PMS). This review article aims to provide an overview of GFAP in the prediction of clinical progression in neuroinflammation, brain tumors, TBI, ischemic stroke, genetic disorders, neurodegeneration and other diseases in the CNS and to explore the potential therapeutic methods.

Current non-invasive strategies for brain drug delivery: overcoming blood-brain barrier transport.

BACKGROUND: The blood-brain barrier (BBB) is a complex and dynamic structure that serves as a gatekeeper, restricting the migrations of most compounds and molecules from blood into the central nervous system (CNS). The BBB plays a crucial role in maintaining CNS physiological function and brain homeostasis. It can protect the CNS from the entrance of toxic and infectious agents, however, it also restricts the drug permeation into brain to play a therapeutic role. The BBB has been the biggest limiting hurdle to medications entering the brain excluding from the brain about 100% of large-molecule and more than 98% of all small-molecule neurotherapeutics. As a result, it is of inability for drug molecule to reach requisite concentrations within the brain. OBJECTIVE: With the aim of enhancing drug permeability and efficacy, a variety of strategies have been developed: invasive approaches, such as intraarterial delivery, intrathecal delivery, or administrating directly the drug intraventricularly and intracerebrally; non-invasive approaches that take advantage of innate BBB functions, using prodrugs, focused ultrasound, intranasal administration or nanotechnology. CONCLUSIONS: Here we mainly review recent developments and challenges related to non-invasive BBB-crossing techniques, whose benefits include higher efficacy, easier application, less treatment burden, better patient acceptability, and adherence. Additionally, we also analyze the potential of non-invasive methods in the treatment of CNS disorders and render them as a most suitable platform for the management of neurological diseases.

Super-resolution imaging of mitochondrial cristae using a more hydrophobic far-red Si-rhodamine probe.

Mitochondrial probe SiRPFA was synthesized by attaching a long perfluoroalkyl chain on Si-rhodamine cationic dye. High lipophilicity endowed SiRPFA with mitochondrial membrane potential independent properties. Under stimulated emission depletion microscopy, SiRPFA clearly revealed changes in mitochondrial cristae morphology during autophagy induced by starvation or apoptosis.

Open-3DSIM: an open-source three-dimensional structured illumination microscopy reconstruction platform.

Open-3DSIM is an open-source reconstruction platform for three-dimensional structured illumination microscopy. We demonstrate its superior performance for artifact suppression and high-fidelity reconstruction relative to other algorithms on various specimens and over a range of signal-to-noise levels. Open-3DSIM also offers the capacity to extract dipole orientation, paving a new avenue for interpreting subcellular structures in six dimensions (xyzθλt). The platform is available as MATLAB code, a Fiji plugin and an Exe application to maximize user-friendliness.

Superresolution structured illumination microscopy reconstruction algorithms: a review.

Structured illumination microscopy (SIM) has become the standard for next-generation wide-field microscopy, offering ultrahigh imaging speed, superresolution, a large field-of-view, and long-term imaging. Over the past decade, SIM hardware and software have flourished, leading to successful applications in various biological questions. However, unlocking the full potential of SIM system hardware requires the development of advanced reconstruction algorithms. Here, we introduce the basic theory of two SIM algorithms, namely, optical sectioning SIM (OS-SIM) and superresolution SIM (SR-SIM), and summarize their implementation modalities. We then provide a brief overview of existing OS-SIM processing algorithms and review the development of SR-SIM reconstruction algorithms, focusing primarily on 2D-SIM, 3D-SIM, and blind-SIM. To showcase the state-of-the-art development of SIM systems and assist users in selecting a commercial SIM system for a specific application, we compare the features of representative off-the-shelf SIM systems. Finally, we provide perspectives on the potential future developments of SIM.

Parameter estimation of the structured illumination pattern based on principal component analysis (PCA): PCA-SIM.

Principal component analysis (PCA), a common dimensionality reduction method, is introduced into SIM to identify the frequency vectors and pattern phases of the illumination pattern with precise subpixel accuracy, fast speed, and noise-robustness, which is promising for real-time and long-term live-cell imaging.

Neuronal Surface Antibody Syndrome: A Review of the Characteristics of the Disease and Its Association with Autoantibodies.

Several studies have certified that autoantibodies play an important role in the manifestation of neuromuscular diseases. Scientists have discovered specific neuronal tumor antibodies in patients with typical paraneoplastic neurological disorders. But in some clinical cases, it is not useful to cure this disease with common treatments unless the autoantibodies are addressed. In addition, recent studies have shown a close relationship between certain antibodies and neuronal surface proteins in some special cases. These antibodies, which act on the surface of neurons, mainly include voltage-gated calcium channel (VGKC) antibodies. VGKC antibodies are further divided into several types including anti-leucine-rich glioma inactivated 1 (LGI1), anti-contactin-associated protein-like 2 (Caspr2), anti-N-methyl-D-aspartate receptor (NMDAR), anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), anti-γ-aminobutyric acid receptor (GABAR), and glycine receptor. For the purpose of this review, cases of clinical studies of autoantibody-associated encephalitis were collected, the key points regarding the pathogenesis were summarized, the clinical manifestation was discussed, and all this information was organized as this review in order to introduce the relationship between autoantibodies and autoimmune encephalitis. Furthermore, it is hoped that it can effectively direct the development of diagnostic and therapeutic approach in the future.

P75 Involved in the Ubiquitination of α-synuclein in Rotenone-based Parkinson's Disease Models.

For Parkinson's disease (PD), the regulatory mechanism of α-synuclein (α-syn) aggregation remains to be clarified. Ubiquitination modification is crucial for α-syn aggregation, with implications for Lewy body formation. Besides, ubiquitin ligase absentia homolog (siAH) is involved in the ubiquitination of α-syn. We investigated whether the p75 receptor can act as a potential regulator of α-syn accumulation through ubiquitination. Western blot, immunoprecipitation, gene transfection, and RNA interference technology were employed to detect the effect of p75 in in vivo and in vitro models. In a rotenone-based stereotactic (ST) infusion in vivo model of PD, p75 receptor and siAH expression was increased significantly compared with the control group. In cellular models of rotenone-mediated neurotoxicity, the interactions between p75 and siAH were revealed by immunoprecipitation; the colocalization of p75 with α-syn was observed in the cytoplasm; p75 promoted nuclear expression of NF-κB (p65), which might interact with the promoter of the siAH gene. Moreover, siRNA-mediated p75 depletion reduced the upregulation of α-syn and nuclear expression of p65 and protected against cell apoptosis induced by rotenone. Thus, aberrant expression of p75 may regulate the increased expression of α-syn, which is related to siAH-mediated ubiquitination and nuclear expression of p65.

Dysregulation of bcl-2 enhanced rotenone-induced α-synuclein aggregation associated with autophagic pathways.

α-Synuclein (α-syn) aggregation has far-reaching implications in the pathogenesis of Parkinson's disease, and the levels of α-syn protein determine its neurotoxic potential. However, the intrinsic pathway of α-syn accumulation and the mode of α-syn degradation remain contentious. Following a stereotactic infusion of rotenone into the substantia nigra and the ventral tegmental area, the chronic rat model of Parkinson's disease was established successfully. In response to the rotenone, increased intracellular α-syn levels and autophagic flux monitored by LC3 II turnover were induced in dopaminergic neurons (TH-positive) of rat substantia nigra and ventral tegmental area. In the cytoplasm, increased immune response of LC3 colocalized with α-syn on the basis of rotenone-mediated neurotoxicity. The immunoreactivity for p62, an adaptor of the autophagy, was upregulated in the cytoplasm and nucleus. The enhancement of autophagy by valproate acid decreased rotenone-induced α-syn aggregation, whereas the inhibition of autophagy by 3-methyladenine increased α-syn aggregation. In addition, the expression of bcl-2 was reduced in rotenone-induced neurotoxicity, accompanied by the enhancement of autophagy. Small interfering RNA-mediated knockdown of bcl-2 expression facilitated the expression of p62 protein and autophagy. Moreover, the inhibition of bcl-2 increased rotenone-based α-syn aggregation. In short, in rotenone-based models, dowregulation of bcl-2 negatively controlled rotenone-induced autophagy and α-syn aggregation.

Protective effect of roscovitine against rotenone-induced parkinsonism.

BACKGROUND: Protective effect of roscovitine and deregulation of the p-RB/E2F1 have not been well studied in PD models generated by repeated oral administration of rotenone. OBJECTIVE: These experiments evaluated the effects of repeated oral gavage of rotenone on the activation of p-RB/E2F1 and the effects of roscovitine on the regulation of dopaminergic neuronal injury and the behavior of PD in mice. METHODS: Using 2.5% carboxymethylcellulose and 1.25% chloroform as a vehicle solution, rotenone (30 mg/kg) was administered via oral gavage once daily for 30 days in C57 mice. Behavioral profiles (pole test and traction test) were assessed in these PD models, and oxidative stress levels were evaluated in the midbrain. The immunoreactivities of TH, α-synuclein (α-syn), p-RB, E2F1 and cleaved caspase-3 in the substantia nigra were examined with a laser confocal microscope. Pharmacological inhibition of cyclin-dependent kinase with roscovitine was achieved by intraperitoneal (IP) injection at a dose of 50 mg/kg daily. RESULTS: All rotenone-administered C57 mice showed the typical behavioral features of PD: stiffness, bradykinesia, or hypokinesia. Behavioral testing with the pole test and traction test indicated that the rotenone group, but not the vehicle group, was affected. Spectrophotometric analysis demonstrated that glutathione (GSH) and superoxide dismutase (SOD) activity was decreased, and the generation of malondialdehyde (MDA) was elevated in the midbrain of the rotenone-treated group. After oral administration of rotenone, a loss of nigral tyrosine hydroxylase (TH)-positive neurons was observed. The immune response of α-syn was enhanced in the cytoplasm of dopaminergic neurons from the rotenone-induced neurotoxicity. Rb phosphorylation at serine 780, which affected Rb binding to E2F, was induced after rotenone treatment. The activation of E2F1, which is involved in the regulation of the cell cycle, was also induced from chronic exposure to rotenone. Moreover, administration of the cell cycle inhibitor roscovitine protected against rotenone-induced nigral dopaminergic neuronal injury and inhibited cleaved caspase-3 activation. Roscovitine also markedly ameliorated the behavior of PD mice. CONCLUSIONS: Mouse models of Parkinson's disease were established by oral rotenone administration and reproduced some of the features of dopaminergic neuronal degeneration. Roscovitine protects against rotenone-induced parkinsonism.

Effects of bromadiolone poisoning on the central nervous system.

Cases of rodenticide poisoning (second-generation long-acting dicoumarin rodenticide, superwarfarin) have occasionally been reported. The main symptoms of bromadiolone poisoning are skin mucosa hemorrhage, digestive tract hemorrhage, and hematuresis. However, the symptoms of central nervous system toxicity have rarely been reported. Our case reports on a 41-year-old male who had no contact with bromadiolone. His main symptoms were dizziness, unsteady gait, and abnormal behavior. Laboratory test results revealed the presence of bromadiolone in his blood and urine, a longer prothrombin time, activated partial thromboplastin time, and a high international normalized ratio. Magnetic resonance imaging of the brain showed that the bilateral posterior limb of the internal capsule, splenium of corporis callosum, and bilateral centrum semiovale formed symmetrical patch distribution. The patient gradually recovered after treated with vitamin K1 and plasma transfusion. Our clinical study could pave the way to improve the detection of bromadiolone poisoning and avoid misdiagnosis.