Perfusion Analysis Using High-Definition Indocyanine Green Angiography in Burn Comb Model.

Indocyanine green angiography (ICGA) has been widely employed for quantitative evaluation of the rat comb burn model, but the imaging equipment, imaging protocol, and fluorescence data interpretation of ICGA remain unsatisfactory. This study aims to provide better solutions for the application of ICGA in perfusion analysis. The rat comb burn model was established under a series of different comb contact durations, including 10, 20, 25, 30, 35, and 40 s. Indocyanine green angiography was used to analyze wound perfusion. In total, 16 rats were divided into ibuprofen and control groups for the burn model, and their perfusion was compared. A total of 16 identical models were divided into standard- and high-dose indocyanine green (ICG) groups, and ICGA was conducted to investigate the dynamic change in wound fluorescence. Escharectomy was performed under real-time fluorescence mapping and navigation. The results showed that a comb contact duration of 30 s was optimum for the burn model. Indocyanine green angiography could accurately evaluate the histologically determined depth of thermal injury and wound perfusion in the rat comb model. Digital subtraction of residual fluorescence was necessary for multiple comparisons of perfusion. Dynamic changes in fluorescence and necrotic tissues were observed more clearly by high-dose (0.5 mg/kg) ICG in angiography. In conclusion, perfusion analysis by ICGA can be used to assess the histologically determined depth of thermal injury and the impact of a specific treatment on wound perfusion. Indocyanine green angiography can help to identify necrotic tissue. The above findings and related imaging protocols lay the foundation for future research.

Interaction mechanism between hydroxychloroquine sulfate and collagen: Insights from multi-spectroscopy, molecular docking, and molecular dynamic simulation methods.

Hydroxychloroquine sulfate (HCQ) can be used to treat various connective tissue diseases. Collagen, which is not only an important drug delivery carrier but also the main component in the connective tissue, is the focus of this study. Here, the interaction mechanism of HCQ with collagen was investigated through various spectroscopic and computational methods. It is found that HCQ binds to collagen spontaneously, primarily via hydrophobic interactions and some hydrogen bonds. The findings of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) verified that formation of HCQ-collagen complex and the amorphous structure, secondary structures, and microstructure of collagen were changed after HCQ binding. A decrease in the relaxation time of free water was observed in the collagen system when HCQ was added. Molecular docking demonstrated that HCQ was almost buried in the cavity of collagen via some hydrophobic interactions with one hydrogen bond, which conforms to the findings of the fluorescence and FTIR analyses. Molecular dynamic (MD) simulations further revealed the structural change information in the docking process. Hopefully, the information generated in this study can provide some useful insights for the research on the pharmacological mechanisms of HCQ in the treatment of the connective tissue diseases and the application of collagen as a drug carrier.

PS1 Affects the Pathology of Alzheimer's Disease by Regulating BACE1 Distribution in the ER and BACE1 Maturation in the Golgi Apparatus.

Neuritic plaques are one of the major pathological hallmarks of Alzheimer's disease. They are formed by the aggregation of extracellular amyloid-ß protein (Aß), which is derived from the sequential cleavage of amyloid-ß precursor protein (APP) by ß- and γ-secretase. BACE1 is the main ß-secretase in the pathogenic process of Alzheimer's disease, which is believed to be a rate-limiting step of Aß production. Presenilin 1 (PS1) is the active center of the γ-secretase that participates in the APP hydrolysis process. Mutations in the PS1 gene (PSEN1) are the most common cause of early onset familial Alzheimer's disease (FAD). The PSEN1 mutations can alter the activity of γ-secretase on the cleavage of APP. Previous studies have shown that PSEN1 mutations increase the expression and activity of BACE1 and that BACE1 expression and activity are elevated in the brains of PSEN1 mutant knock-in mice, compared with wild-type mice, as well as in the cerebral cortex of FAD patients carrying PSEN1 mutations, compared with sporadic AD patients and controls. Here, we used a Psen1 knockout cell line and a PS1 inhibitor to show that PS1 affects the expression of BACE1 in vitro. Furthermore, we used sucrose gradient fractionation combined with western blotting to analyze the distribution of BACE1, combined with a time-lapse technique to show that PS1 upregulates the distribution and trafficking of BACE1 in the endoplasmic reticulum, Golgi, and endosomes. More importantly, we found that the PSEN1 mutant S170F increases the distribution of BACE1 in the endoplasmic reticulum and changes the ratio of mature BACE1 in the trans-Golgi network. The effect of PSEN1 mutations on BACE1 may contribute to determining the phenotype of early onset FAD.

Induction of A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 by a rare variant or cognitive activities reduces hippocampal amyloid-ß and consequent Alzheimer's disease risk.

Amyloid-ß (Aß) derived from amyloid precursor protein (APP) hydrolysis is acknowledged as the predominant hallmark of Alzheimer's disease (AD) that especially correlates to genetics and daily activities. In 2019, meta-analysis of AD has discovered five new risk loci among which A Disintegrin and Metalloproteinase with Thrombospondin motifs 1 (ADAMTS1) has been further suggested in 2021 and 2022. To verify the association, we re-sequenced ADAMTS1 of clinical AD samples and subsequently identified a novel rare variant c.-2067A > C with watchable relevance (whereas the P-value was not significant after adjustment). Dual-luciferase assay showed that the variant sharply stimulated ADAMTS1 expression. In addition, ADAMTS1 was also clearly induced by pentylenetetrazol-ignited neuronal activity and enriched environment (EE). Inspired by the above findings, we investigated ADAMTS1's role in APP metabolism in vitro and in vivo. Results showed that ADAMTS1 participated in APP hydrolysis and consequently decreased Aß generation through inhibiting ß-secretase-mediated cleavage. In addition, we also verified that the hippocampal amyloid load of AD mouse model was alleviated by the introduction of ADAMTS1, and thus spatial cognition was restored as well. This study revealed the contribution of ADAMTS1 to the connection of genetic and acquired factors with APP metabolism, and its potential in reducing hippocampal amyloid and consequent risk of AD.

Pharmacological induction of AMFR increases functional EAAT2 oligomer levels and reduces epileptic seizures in mice.

Dysregulation of excitatory amino acid transporter 2 (EAAT2) contributes to the development of temporal lobe epilepsy (TLE). Several strategies for increasing total EAAT2 levels have been proposed. However, the mechanism underlying the oligomeric assembly of EAAT2, impairment of which inhibits the formation of functional oligomers by EAAT2 monomers, is still poorly understood. In the present study, we identified E3 ubiquitin ligase AMFR as an EAAT2-interacting protein. AMFR specifically increased the level of EAAT2 oligomers rather than inducing protein degradation through K542-specific ubiquitination. By using tissues from humans with TLE and epilepsy model mice, we observed that AMFR and EAAT2 oligomer levels were simultaneously decreased in the hippocampus. Screening of 2386 FDA-approved drugs revealed that the most common analgesic/antipyretic medicine, acetaminophen (APAP), can induce AMFR transcriptional activation via transcription factor SP1. Administration of APAP protected against pentylenetetrazol-induced epileptogenesis. In mice with chronic epilepsy, APAP treatment partially reduced the occurrence of spontaneous seizures and greatly enhanced the antiepileptic effects of 17AAG, an Hsp90 inhibitor that upregulates total EAAT2 levels, when the 2 compounds were administered together. In summary, our studies reveal an essential role for AMFR in regulating the oligomeric state of EAAT2 and suggest that APAP can improve the efficacy of EAAT2-targeted antiepileptic treatments.

[Expression and Clinical Significance of CTGF in Patients with Multiple Myeloma].

OBJECTIVE: To detect the relationship between CTGF in the bone marrow of MM patients and osteolytic lesion of myeloma, moreover, to investigate the clinical significance of CTGF in MM. METHODS: Fifity-four MM patients treated in our hospital from March 2019 to April 2020 were enrolled, and 28 healthy volunteers were selected as the control group. The plasma in bone marrow of the patients was collected, and the ELISA was used to detect the level of CTGF in bone marrow plasma and the relationship between its and clinical characteristics were statistically analyzed. RESULTS: The CTGF level of MM patients was significantly higher than those in the healthy control group (P<0.001); the CTGF level in male patients was higher than that in female patients (P=0.007); the CTGF level in MM patients with osteolytic lesions was significantly higher than patients without osteolytic lesions and controls (P=0.007, P=0.001). The CTGF level in MM patients was positively correlated with the number of bone lesions (P<0.001, r=0.52). CTGF levels in patients with ≥3 bone lesions were significantly higher than those with <3 bone lesions and without bone lesions (P=0.014, P=0.002). ROC curve result showed that CTGF expression level shows a significant diagnostic value for MM bone disease (P<0.001). CONCLUSION: The abnormally high expression of CTGF level in MM patients is related to the degree of myelomas osteolytic lesions and can reflect the progress of MM.

Mutations of beta-amyloid precursor protein alter the consequence of Alzheimer's disease pathogenesis.

Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-ß (Aß). Approximately 25 mutations in ß-amyloid precursor protein (APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aß generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations (A673T, A673V, E682K, E693G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aß1-40 and Aß1-42 levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673T mutation decreases Aß42/Aß40 rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673V, E682K, and E693Q mutations promote Aß42/Aß40 rate by increasing levels of CTF99, Aß42, Aß40, and IAT, and decreasing VVIA levels. Pathogenic E693G mutation shows no significant change in Aß42/Aß40 ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aß generation by affecting the long Aß cleavage pathway and increasing Aß42/40 rate, thereby resulting in Alzheimer's disease.

Discovery of efficient stimulators for adult hippocampal neurogenesis based on scaffolds in dragon's blood.

Reduction of hippocampal neurogenesis caused by aging and neurological disorders would impair neural circuits and result in memory loss. A new lead compound (N-trans-3',4'-methylenedioxystilben-4-yl acetamide 27) has been discovered to efficiently stimulate adult rats' neurogenesis. In-depth structure-activity relationship studies proved the necessity of a stilbene scaffold that is absent in highly cytotoxic analogs such as chalcones and heteroaryl rings and inactive analogs such as diphenyl acetylene and diphenyl ethane, and validated the importance of an NH in the carboxamide and a methylenedioxy substituent on the benzene ring. Immunohistochemical staining and biochemical analysis indicate, in contrast to previously reported neuroprotective chemicals, N-stilbenyl carboxamides have extra capacity for neuroproliferation-type neurogenesis, thereby providing a foundation for improving the plasticity of the adult mammalian brain.

Effect of Presenilin Mutations on APP Cleavage; Insights into the Pathogenesis of FAD.

Alzheimer disease (AD) is characterized by progressive memory loss, reduction in cognitive functions, and damage to the brain. The ß-amyloid precursor protein can be sequentially cleaved by ß- secretase and γ-secretase. Mutations in the presenilin1(PS1) are the most common cause of Familial Alzheimer's disease (FAD). PS1 mutations can alter the activity of γ-secretase on the cleavage of the ß-amyloid precursor protein, causing increased Aß production. Previous studies show that the ßAPP-C-terminal fragment is first cleaved by ß-scretase, primarily generating long fragments of Aß48 and Aß49, followed by the stepwise cleavage of every three amino acid residues at the C terminus, resulting in Aß48-, 45-, 42 line and Aß49-, 46-, 43-, 40 line. Here, we used LC-MS/MS to analyze unique peptides IAT, VVIA, ITL, TVI, IVI through sequential cleavage, combined with ELISA to test the level of Aß42 and Aß40 for validation. The results show that most FAD mutant PS1 can alter the level of Aß42 and Aß40 monitored by the Aß42/Aß40 ratio. Among them, six mutants (I143T, H163P, S170F, Q223R, M233V, and G384A) affect the Aß42/40 ratio through both Aß49-40 and Aß48-38 lines; L166P through decreasing the Aß49-40 line, six mutants (I143V, M146V, G217A, E280A, L381V, and L392V) through increasing the Aß48-42 line. More importantly, we found some mutations can affect the γ-secretase cleavage preference of α-CTF and ß-CTF. In conclusion, we found that the FAD PS1 mutations mainly increase the generation of Aß42 by decreasing the cleavage of Aß42-Aß38 and Aß43-Aß40.