Histomorphological analysis of perfusion parameters and CNS lymphatic vessels in mice: an experimental method study.

To investigate the distribution and characteristics of lymphatic vessels within the central nervous system, we focus on the meninges of the spinal cord and brain parenchyma in mice. Additionally, we aim to provide experimental methods for obtaining optimal imaging and clear structures of lymphatic vessels, while optimizing the perfusion parameters to improve histomorphological quality. Male C57BL/6J mice were randomly divided into four groups, with each group assigned a specific perfusion parameter based on perfusion volumes and temperatures. Immunofluorescence staining of lymphatics and blood vessels was performed on both meningeal and the brain tissue samples. Statistical analysis was performed using one-way analysis of variance to compare the groups, and a significant level of P < 0.05 was considered statistically significant. Our study reports the presence of lymphatic vessels in the meninges of the spinal cord and brain parenchyma in mice. We highlight the crucial role of high perfusion volume of paraformaldehyde with low temperature in fixation for achieving optimal results. We provide experimental methods for obtaining optimal imaging and clear structures of lymphatic vessels in the meninges of the spinal cord and brain parenchyma in mice, which contribute to our understanding of the distribution and characteristics of lymphatic vessels within the central nervous system. Further research is warranted to explore the functional implications of these lymphatic vessels and their potential therapeutic significance in neurodegenerative and neuroinflammatory diseases.

The relationship between father absence and hostility among Chinese depressed youths: A serial mediation model and the role of self-esteem and frustration tolerance.

Background: While the association between father absence and youth hostility has been well-documented among depressed youths, there is a lack of research on the potential mechanism underlying such an association. This study aimed to test a serial mediation model of self-esteem and frustration tolerance on the link between father absence and youth hostility. Methods: A total of 137 Chinese youths with major depressive disorder were recruited from Wuhan Mental Health Center. They completed a survey including the Father Absence Questionnaire to measure father absence, the Chinese Hostility Inventory (CHI) to measure hostility, the Psychological Endurance Questionnaire to measure frustration tolerance, and the Self-esteem Scale (SES) to measure self-esteem. A series of multiple linear regression models were employed to assess the associations among father absence, self-esteem, frustration tolerance, and hostility. Results: Although father absence was modestly associated with hostility (r = 0.30, p < 0.001), subsequent serial mediation analysis showed that father absence was not directly related to hostility (ß = 0.06, p = 0.29) when self-esteem and frustration tolerance were included in the model. High levels of father absence had an adverse effect on levels of self-esteem, which decreased levels of frustration tolerance, and thus higher levels of hostility among depressed youths. The indirect effects of father absence on hostility through self-esteem, frustration tolerance, as well as through self-esteem and frustration tolerance serially accounted for 28%, 24%, and 24% of the total effect, respectively. Conclusion: Our study tested a serial mediation model of self-esteem and frustration tolerance as mediators between father absence and hostility among depressed youths. The findings strengthened our understanding of the potential mechanism underlying the association between self-esteem and frustration tolerance, which may provide useful guidance for future intervention programs.

Superparamagnetic iron oxide nanoparticles conjugated with Aß oligomer-specific scFv antibody and class A scavenger receptor activator show therapeutic potentials for Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder. No disease-modifying strategy to prevent or delay AD progression currently exists. Aß oligomers (AßOs), rather than monomers or fibrils, are considered as the primary neurotoxic species. Therapeutic approaches that direct against AßOs and promote Aß clearance may have great value for AD treatment. RESULTS: We here reported a multifunctional superparamagnetic iron oxide nanoparticle conjugated with Aß oligomer-specific scFv antibody W20 and class A scavenger receptor activator XD4 (W20/XD4-SPIONs). Besides the diagnostic value, W20/XD4-SPIONs retained the anti-Aß properties of W20 and XD4 by inhibiting Aß aggregation, attenuating AßO-induced cytotoxicity and increasing microglial phagocytosis of Aß. When applied to APP/PS1 mice, W20/XD4-SPIONs significantly rescued cognitive deficits and alleviated neuropathology of AD mice. CONCLUSION: These results suggest that W20/XD4-SPIONs show therapeutic benefits for AD. In combination with the early diagnostic property, W20/XD4-SPIONs present as a promising agent for early-stage AD diagnosis and intervention.

Multifunctional Superparamagnetic Iron Oxide Nanoparticles Conjugated with Aß Oligomer-Specific scFv Antibody and Class A Scavenger Receptor Activator Show Early Diagnostic Potentials for Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Diagnosing AD before symptoms arise will facilitate earlier intervention. The early diagnostic approaches are thus urgently needed. METHODS: The multifunctional nanoparticles W20/XD4-SPIONs were constructed by the conjugation of oligomer-specific scFv antibody W20 and class A scavenger receptor (SR-A) activator XD4 onto superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs' stability and uniformity in size were measured by dynamic light scattering and transmission electron microscopy. The ability of W20/XD4-SPIONs for recognizing Aß oligomers (AßOs) and promoting AßOs phagocytosis was assessed by immunocytochemistry and flow cytometry analysis. The blood-brain barrier permeability of W20/XD4-SPIONs was determined by a co-culture transwell model. The in vivo probe distribution of W20/XD4-SPIONs in AD mouse brains was detected by magnetic resonance imaging (MRI). RESULTS: W20/XD4-SPIONs, as an AßOs-targeted molecular MRI contrast probe, readily reached pathological AßOs regions in brains and distinguished AD transgenic mice from WT controls. W20/XD4-SPIONs retained the property of XD4 for SR-A activation and significantly promoted microglial phagocytosis of AßOs. Moreover, W20/XD4-SPIONs exhibited the properties of good biocompatibility, high stability and low cytotoxicity. CONCLUSION: Compared with W20-SPIONs or XD4-SPIONs, W20/XD4-SPIONs show the highest efficiency for AßOs-targeting and significantly enhance AßOs uptake by microglia. As a molecular probe, W20/XD4-SPIONs also specifically and sensitively bind to AßOs in AD brains to provide an MRI signal, demonstrating that W20/XD4-SPIONs are promising diagnostic agents for early-stage AD. Due to the beneficial effect of W20 and XD4 on neuropathology, W20/XD4-SPIONs may also have therapeutic potential for AD .

Yeast-Based Aß1-15 Vaccine Elicits Strong Immunogenicity and Attenuates Neuropathology and Cognitive Deficits in Alzheimer's Disease Transgenic Mice.

Immunotherapy focusing on reducing the amyloid-beta (Aß) burden is a promising treatment strategy for Alzheimer's disease (AD). Many clinical studies on AD immunotherapies have failed due to low safety and efficacy, calling for a highly potent AD vaccine which induces sufficient antibody titer while avoiding side effects. Here, we designed a yeast-based vaccine Y-5A15 comprising five copies of Aß1-15 displayed on the surface of yeast cell wall, and we subcutaneously immunized APP/PS1 mice three times. Our results demonstrated that the Y-5A15 remarkably enhanced the Aß epitope immunogenicity and elicited high antibody titers against Aß in AD mice. Importantly, Y-5A15 vaccination successfully reduced Aß levels, plaque burden and glial activation, rescued synaptic deficits and significantly ameliorated memory and cognitive decline in APP/PS1 transgenic mice, suggesting that the yeast-based Aß epitope vaccine has a promising potency for the treatment of AD.

Knowledge, attitudes, and practices towards COVID-19 among Chinese residents during the rapid rise period of the COVID-19 outbreak: a quick online cross-sectional survey.

Unprecedented measures have been adopted to control the rapid spread of the ongoing COVID-19 epidemic in China. People's adherence to control measures is affected by their knowledge, attitudes, and practices (KAP) towards COVID-19. In this study, we investigated Chinese residents' KAP towards COVID-19 during the rapid rise period of the outbreak. An online sample of Chinese residents was successfully recruited via the authors' networks with residents and popular media in Hubei, China. A self-developed online KAP questionnaire was completed by the participants. The knowledge questionnaire consisted of 12 questions regarding the clinical characteristics and prevention of COVID-19. Assessments on residents' attitudes and practices towards COVID-19 included questions on confidence in winning the battle against COVID-19 and wearing masks when going out in recent days. Among the survey completers (n=6910), 65.7% were women, 63.5% held a bachelor degree or above, and 56.2% engaged in mental labor. The overall correct rate of the knowledge questionnaire was 90%. The majority of the respondents (97.1%) had confidence that China can win the battle against COVID-19. Nearly all of the participants (98.0%) wore masks when going out in recent days. In multiple logistic regression analyses, the COVID-19 knowledge score (OR: 0.75-0.90, P<0.001) was significantly associated with a lower likelihood of negative attitudes and preventive practices towards COVID-2019. Most Chinese residents of a relatively high socioeconomic status, in particular women, are knowledgeable about COVID-19, hold optimistic attitudes, and have appropriate practices towards COVID-19. Health education programs aimed at improving COVID-19 knowledge are helpful for Chinese residents to hold optimistic attitudes and maintain appropriate practices. Due to the limited sample representativeness, we must be cautious when generalizing these findings to populations of a low socioeconomic status.

A biomimetic yeast shell vaccine coated with layered double hydroxides induces a robust humoral and cellular immune response against tumors.

Enhancing both the humoral and cellular immune response for tumor vaccination remains a challenge. Inspired by natural pathogen structures, we took ß-glucan particles derived from a baker's yeast cell shell (YS) as a vaccine carrier and danger signal for dendritic cells (DCs), and coated the YS with catanionic layered double hydroxides (LDH) by electrostatic adsorption to form a biomimetic yeast cell particle (YSL). Our experimental results showed that the YSL vaccine efficiently targeted antigen-presenting cells (APCs) and remarkably enhanced antigen cross-presentation, and strongly improved the activation and maturation of DCs. Moreover, the YSL vaccine elicited an extremely high antibody titer and strong antigen-specific cytotoxic T lymphocyte together with mixed Th1/Th17 cellular immune responses and induced marked prophylactic and therapeutic effects against E.G7-OVA tumors in mouse models. These results suggest that YSL, integrating a yeast shell to mimic natural pathogens and LDH with high antigen-loading capacity and lysosome escape, is a promising tumor vaccine platform for rapid, effective and strong induction of both humoral and cellular immune responses.

ScFv-conjugated superparamagnetic iron oxide nanoparticles for MRI-based diagnosis in transgenic mouse models of Parkinson's and Huntington's diseases.

It is widely accepted that amyloid oligomers are the most toxic species to initiate the pathologic processes of Parkinson's disease (PD) and Huntingdon's disease (HD). But there is no definitive diagnosis for PD and HD at their early stages. Here, we conjugated an amyloid oligomer-specific scFv antibody (W20) to PEGylated superparamagnetic iron oxide nanoparticles (SPIONs) and detected the properties of the SPIONs conjugated with W20. The results showed that W20-SPIONs, with the size of around 11.8 nm in diameter, were stable and nontoxic, and had enough relaxation capacity to be used as an MRI contrast agent. When applied to the transgenic mouse models of PD and HD, W20-SPIONs crossed the blood-brain barrier and specifically bound to the oligomer area to give MRI signal, distinguishing PD and HD from healthy controls. These results indicated that W20-SPIONs had potential in early-stage diagnosis for PD and HD and also opened up a new strategy for evaluating the efficacy of new drugs.

Naturally occurring autoantibodies against α-synuclein rescues memory and motor deficits and attenuates α-synuclein pathology in mouse model of Parkinson's disease.

It has been suggested that aggregation of α-synuclein (α-syn) into oligomers leads to neurodegeneration in Parkinson's disease (PD), but intravenous immunoglobulin (IVIG) which contains antibodies against α-syn monomers and oligomers fails to treat PD mouse model. The reason may be because IVIG contains much low level of antibodies against α-syn, and of which only a small part can penetrate the blood-brain barrier, resulting in an extremely low level of effective antibodies in the brain, and limiting the beneficial effect of IVIG on PD mice. Here, we first isolated naturally occurring autoantibodies against α-syn (NAbs-α-syn) from IVIG. Our further investigation results showed that NAbs-α-syn inhibited α-syn aggregation and attenuated α-syn-induced cytotoxicity in vitro. Compared with vehicles, NAbs-α-syn significantly attenuated the memory and motor deficits by reducing the levels of soluble α-syn, total human α-syn and α-syn oligomers, decreasing the intracellular p-α-synser129 deposits and axonal pathology, inhibiting the microgliosis and astrogliosis, as well as the production of proinflammatory cytokines, increasing the levels of PSD95, synaptophysin and TH in the brain of A53T transgenic mice. These findings suggest that NAbs-α-syn overcomes the deficiency of IVIG and exhibits a promising therapeutic potential for the treatment of PD.

PLGA nanoparticles modified with a BBB-penetrating peptide co-delivering Aß generation inhibitor and curcumin attenuate memory deficits and neuropathology in Alzheimer's disease mice.

Alzheimer's disease (AD) is the most common form of dementia, characterized by the formation of extracellular senile plaques and neuronal loss caused by amyloid ß (Aß) aggregates in the brains of AD patients. Conventional strategies failed to treat AD in clinical trials, partly due to the poor solubility, low bioavailability and ineffectiveness of the tested drugs to cross the blood-brain barrier (BBB). Moreover, AD is a complex, multifactorial neurodegenerative disease; one-target strategies may be insufficient to prevent the processes of AD. Here, we designed novel kind of poly(lactide-co-glycolic acid) (PLGA) nanoparticles by loading with Aß generation inhibitor S1 (PQVGHL peptide) and curcumin to target the detrimental factors in AD development and by conjugating with brain targeting peptide CRT (cyclic CRTIGPSVC peptide), an iron-mimic peptide that targets transferrin receptor (TfR), to improve BBB penetration. The average particle size of drug-loaded PLGA nanoparticles and CRT-conjugated PLGA nanoparticles were 128.6 nm and 139.8 nm, respectively. The results of Y-maze and new object recognition test demonstrated that our PLGA nanoparticles significantly improved the spatial memory and recognition in transgenic AD mice. Moreover, PLGA nanoparticles remarkably decreased the level of Aß, reactive oxygen species (ROS), TNF-α and IL-6, and enhanced the activities of super oxide dismutase (SOD) and synapse numbers in the AD mouse brains. Compared with other PLGA nanoparticles, CRT peptide modified-PLGA nanoparticles co-delivering S1 and curcumin exhibited most beneficial effect on the treatment of AD mice, suggesting that conjugated CRT peptide, and encapsulated S1 and curcumin exerted their corresponding functions for the treatment.