Alleviation of behavioral deficits, amyloid-ß deposition, and mitochondrial structure damage associated with mitophagy upregulation in AD animal models via AAV9-IGF-1 treatment.

By safeguarding the neurological system, insulin-like growth factor 1 (IGF-1) may have a role in the etiology of Alzheimer's disease (AD). The mechanism and signaling route, however, remain unclear. This research aimed to investigate the impact of IGF-1 on AD as well as its possible mechanism and signaling route. In this work, intracerebroventricular AAV9-IGF-1 was delivered to APP/PS1 transgenic mice. Following therapy, the Morris water maze and passive avoidance tests were administered to evaluate spatial learning and memory. The elevated plus maze, the open field test, and the sucrose preference test were used to evaluate anxious-depressive-like behavior. Thioflavin S staining was employed to visualize Aß deposition, and ELISA was used to determine the quantities of soluble Aß1-40 and Aß1-42. Transmission electron microscopy was used to view the mitochondrial structure and mitophagy vesicles. The protein expression levels of PINK1, Parkin, and LC3-II/LC3-I were finally determined by Western blotting. AAV9-IGF-1 therapy enhanced spatial learning and memory, relieved anxious-depressive-like behavior impairments, lowered amyloid-ß deposition, and decreased levels of soluble Aß1-40 and Aß1-42. In addition, AAV9-IGF-1 therapy restored mitochondrial integrity and increased the number of mitophagy in transgenic mice expressing APP/PS1. These results indicate that IGF-1 is protective for APP/PS1 mice. The mechanism of the favorable benefits mediated by IGF-1 was connected to an increase in mitophagy, which might give a novel therapy target in the future.

[Diosgenin alleviates NAFLD induced by a high-fat diet in rats via mTOR/SREBP-1c/HSP60/MCAD/SCAD signaling pathway].

This study aims to observe the effects of diosgenin on the expression of mammalian target of rapamycin(mTOR), sterol regulatory element-binding protein-1c(SREBP-1c), heat shock protein 60(HSP60), medium-chain acyl-CoA dehydrogenase(MCAD), and short-chain acyl-CoA dehydrogenase(SCAD) in the liver tissue of the rat model of non-alcoholic fatty liver disease(NAFLD) and explore the mechanism of diosgenin in alleviating NAFLD. Forty male SD rats were randomized into five groups: a control group, a model group, low-(150 mg·kg~(-1)·d~(-1)) and high-dose(300 mg·kg~(-1)·d~(-1)) diosgenin groups, and a simvastatin(4 mg·kg~(-1)·d~(-1)) group. The rats in the control group were fed with a normal diet, while those in the other four groups were fed with a high-fat diet. After feeding for 8 weeks, the body weight of rats in the high-fat diet groups increased significantly. After that, the rats were administrated with the corresponding dose of diosgenin or simvastatin by gavage every day for 8 weeks. The levels of triglyceride(TG), total cholesterol(TC), alanine transaminase(ALT), and aspartate transaminase(AST) in the serum were determined by the biochemical method. The levels of TG and TC in the liver were measured by the enzyme method. Oil-red O staining was employed to detect the lipid accumulation, and hematoxylin-eosin(HE) staining to detect the pathological changes in the liver tissue. The mRNA and protein levels of mTOR, SREBP-1c, HSP60, MCAD, and SCAD in the liver tissue of rats were determined by real-time fluorescence quantitative polymerase chain reaction(RT-qPCR) and Western blot, respectively. Compared with the control group, the model group showed increased body weight, food uptake, liver index, TG, TC, ALT, and AST levels in the serum, TG and TC levels in the liver, lipid deposition in the liver, obvious hepatic steatosis, up-regulated mRNA and protein expression levels of mTOR and SREBP-1c, and down-regulated mRNA and protein expression levels of HSP60, MCAD, and SCAD. Compared with the model group, the rats in each treatment group showed obviously decreased body weight, food uptake, liver index, TG, TC, ALT, and AST levels in the serum, TG and TC levels in the liver, lessened lipid deposition in the liver, ameliorated hepatic steatosis, down-regulated mRNA and protein le-vels of mTOR and SREBP-1c, and up-regulated mRNA and protein levels of HSP60, MCAD, and SCAD. The high-dose diosgenin outperformed the low-dose diosgenin and simvastatin. Diosgenin may prevent and treat NAFLD by inhibiting the expression of mTOR and SREBP-1c and promoting the expression of HSP60, MCAD, and SCAD to reduce lipid synthesis, improving mitochondrial function, and promoting fatty acid ß oxidation in the liver.

Bibliometric analysis of residual cardiovascular risk: trends and frontiers.

BACKGROUND: The presence of residual cardiovascular risk is an important cause of cardiovascular events. Despite the significant advances in our understanding of residual cardiovascular risk, a comprehensive analysis through bibliometrics has not been performed to date. Our objective is to conduct bibliometric studies to analyze and visualize the current research hotspots and trends related to residual cardiovascular risk. This will aid in understanding the future directions of both basic and clinical research in this area. METHODS: The literature was obtained from the Web of Science Core Collection database. The literature search date was September 28, 2022. Bibliometric indicators were analyzed using CiteSpace, VOSviewer, Bibliometrix (an R package), and Microsoft Excel. RESULT: A total of 1167 papers were included, and the number of publications is increasing rapidly in recent years. The United States and Harvard Medical School are the leading country and institution, respectively, in the study of residual cardiovascular risk. Ridker PM and Boden WE are outstanding investigators in this field. According to our research results, the New England Journal of Medicine is the most influential journal in the field of residual cardiovascular risk, whereas Atherosclerosis boasts the highest number of publications on this topic. Analysis of keywords and landmark literature identified current research hotspots including complications of residual cardiovascular risk, risk factors, and pharmacological prevention strategies. CONCLUSION: In recent times, global attention toward residual cardiovascular risk has significantly increased. Current research is focused on comprehensive lipid-lowering, residual inflammation risk, and dual-pathway inhibition strategies. Future efforts should emphasize strengthening international communication and cooperation to promote the comprehensive evaluation and management of residual cardiovascular risk.

scAAV9-VEGF alleviates symptoms of amyotrophic lateral sclerosis (ALS) mice through regulating aromatase.

Amyotrophic lateral sclerosis (ALS) is an adult-onset, chronic, progressive, and fatal neurodegenerative disease that leads to progressive atrophy and weakness of the muscles throughout the body. Herein, we found that the intrathecal injection of adeno-associated virus (AAV)-delivered VEGF in SOD1-G93A transgenic mice, as well as ALS mice, could significantly delay disease onset and preserve motor functions and neurological functions, thus prolonging the survival of mice models. Moreover, we found that VEGF treatment could induce the elevated expression of aromatase, which is a key enzyme in estrogen synthesis, in neurons but not in astrocytes. On the other hand, the changes in the expression of oxidative stress-related factors HO-1 and GCLM and autophagy-related proteins p62 and LC3II upon the administration of VEGF revealed the involvement of oxidative stress and autophagy underlying the downstream of the VEGF-induced mitigation of ALS. In conclusion, this study proved the protective effects of VEGF in the onset and development of ALS and revealed the involvement of estrogen, oxidative stress and autophagy in the VEGF-induced alleviation of ALS. Our results highlighted the potential of VEGF as a promising therapeutic agent in the treatment of ALS.

Effect of orexin-A on mitochondrial biogenesis, mitophagy and structure in HEK293-APPSWE cell model of Alzheimer's disease.

Mitochondrial dysfunction plays a key role in the pathogenesis and progression of Alzheimer's Disease (AD). Our previous studies showed that over expression of AD-associated mutant ß-amyloid precursor protein (APP) led to abnormalities of mitochondrial biogenesis and mitophagy, leading to mitochondrial dysfunction. However, the mechanism remains unclear. In this study, we investigated the effect of orexin-A on mitochondrial biogenesis, mitophagy and mitochondrial structure in overexpression of AD-associated mutant APP cells. We used 20E2 cells as the AD cell model. 20E2 cells were treated with orexin-A (50, 100 nmol/L). The effect of different concentrations of orexin-A on cell activity was detected by MTT. As compared with the non-treated 20E2 cells, orexin-A-treated 20E2 cells showed increased expression of APP, decreased cell viability and decreased adenosine triphosphate (ATP) level, decreased levels of regulatory proteins of mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1-alpha [PGC-1α], nuclear respiratory factor 1/2 [NRF1/2], mitochondrial transcription factor A [TFAM]), increased levels of regulatory proteins of mitophagy (Parkin, PTEN-induced putative kinase 1 [PINK1], microtubule-associated protein light chain 3 II/I [LC3-II/LC3-I]) and decreased p62 level, with damaged mitochondrial structure. Orexin-A may reduce mitochondrial biogenesis, enhance mitophagy and damage mitochondrial structure in AD.

Long-term oral melatonin alleviates memory deficits, reduces amyloid-ß deposition associated with downregulation of BACE1 and mitophagy in APP/PS1 transgenic mice.

Melatonin is a tryptophan metabolite synthesized by the pineal gland. Recent research showed that melatonin has a protective effect in Alzheimer's disease (AD). However, its exact mechanism is still unclear. This study was designed to investigate the effects of long-term oral melatonin on spatial learning and memory, Aß deposition and soluble Aß levels, amyloidogenic amyloid precursor protein (APP) processing, mitochondrial structure and mitophagy in APP/PS1 transgenic mice, a model of AD. The spatial learning and memory ability of mice were examined by using the Morris water maze. Thioflavin S staining was used to observe Aß deposition. ELISA was used to evaluate the levels of Aß40 and Aß42. The expression levels of mitophagy proteins (PINK1, Parkin, LC3-II and LC3-I) and amyloidogenic APP processing proteins (BACE1, APP and CTFß) were examined by western blotting analysis. Finally, transmission electron microscopy was used to observe mitochondrial structure and mitophagy vesicles. Our results showed that APP/PS1 transgenic mice with long-term oral melatonin showed improved spatial learning, alleviated memory impairment, reduced Aß deposition and restrained damage of mitochondrial structure. In addition, the number of mitophagy vesicles and expression levels of mitophagy factors (PINK1, Parkin, LC3-II/LC3-I) were decreased, as was the expression levels of amyloidogenic APP processing proteins (BACE1, APP and CTFß). Long-term oral melatonin decreased Aß deposition and improved spatial learning and memory in APP/PS1 transgenic mice by a mechanism associated with down-regulation of BACE1 and mitophagy.

Orexin-A aggravates cytotoxicity and mitochondrial impairment in SH-SY5Y cells transfected with APPswe via p38 MAPK pathway.

BACKGROUND: Alzheimer's disease (AD) is one of the common neurodegenerative diseases and is characterized by the accumulation of amyloid-ß (Aß). Orexin-A is a neuropeptide produced in the hypothalamus and thought to be involved in the pathogenesis of AD. However, its underlying mechanism and signaling pathway remains unclear. The aim of this work was to investigate the effect of Orexin-A on AD, and to explore its potential mechanism and signaling pathway. METHODS: SH-SY5Y cells that were stably transfected with the Swedish mutant amyloid precursor protein (APPswe), a cell model of AD with excessive Aß production, were used in this study. Cells were treated with Orexin-A, and with or without SB203580, an inhibitor of the p38 mitogen-activated protein kinase (MAPK) pathway, one of the key MAPK pathways associated with cell death. Following treatment, cells were collected and analyzed by western blotting, ELISA, electron microscopy, real-time PCR, fluorescence microscopy, and other biochemical assays. RESULTS: Orexin-A increased the level of Aß1-40 and Aß1-42 in the cell medium, and activated the p38 MAPK pathway. As evidenced by the CCK-8 and ELISA BrdU assays, Orexin-A decreased cell viability and cell proliferation. Electron microscopic analysis used to observe the morphology of mitochondria, showed that Orexin-A increased the percentage of abnormal mitochondria. Further, decreased activity of cytochrome c oxidase (CCO), level of ATP, and mitochondrial DNA (mtDNA) copy number following Orexin-A treatment showed that Orexin-A exacerbated mitochondrial dysfunction. The level of intracellular reactive oxygen species (ROS), which is mainly generated in mitochondria and reflects mitochondrial dysfunction, was also increased by Orexin-A. SB203580 blocked the cytotoxicity and mitochondrial impairment aggravated by Orexin-A. CONCLUSIONS: These findings demonstrate that Orexin-A aggravates cytotoxicity and mitochondrial impairment in SH-SY5Y cells transfected with APPswe through the p38 MAPK pathway, and suggest that Orexin-A participates in the pathogenesis of AD, which may provide a new treatment target in the future.

Orexin-A exacerbates Alzheimer's disease by inducing mitochondrial impairment.

Alzheimer's disease (AD) is a progressive neurodegenerative disease which is characterized by the accumulation of amyloid-ß peptide (Aß). Orexin-A is a neuropeptide which has been reported to participate in the pathogenesis of AD. Thus, we aimed to investigate the possible mechanism by which Orexin-A acts in AD. APP/PS1 transgenic mice, an animal model of AD, were intracerebroventricularly injected with Orexin-A. Aß-treated SH-SY5Y cells were used as a cell model of AD and treated with Orexin-A. The Morris water maze test, fluorescence microscopy, enzyme-linked immunosorbent assay (ELISA), electron microscopy, real-time PCR, and other biochemical assays were conducted. The Morris water maze test showed that Orexin-A aggravated cognitive deficit in APP/PS1 mice. Using thioflavine-S staining and ELISA, we found that Orexin-A promoted Aß accumulation in APP/PS1 mice. By evaluating mitochondrial morphology, cytochrome c oxidase activity, ATP level, mitochondrial DNA copy number, and reactive oxygen species, we found that Orexin-A aggravated mitochondrial impairment in APP/PS1 mice and Aß-treated SH-SY5Y cells. Our results indicate that Orexin-A exacerbates AD by inducing mitochondrial impairment. This is a new mechanism that explains how Orexin-A participates in the pathogenesis of AD.

A novel cysteine-sparing G73A mutation of NOTCH3 in a Chinese CADASIL family.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disease leading to stroke and vascular dementia. CADASIL is an inherited small blood vessel disease caused by mutations in the gene encoding the neurogenic locus notch homolog protein 3 (NOTCH3). NOTCH3 is large type I membrane receptor mainly expressed in vascular smooth muscle cells and pericytes. Most identified mutations result in insert or deletion of a cysteine residue within the EGF-like repeats. To date, some cases with a cysteine-sparing mutant have been described. Genetic analysis revealed a novel mutation in NOTCH3 in a CADASIL family. Molecular analysis revealed its potential pathogenic mechanism in causing CADASIL. In this paper, we present a Chinese family with a novel cysteine-sparing mutation in exon 3 (c.218G>C, p.G73A) of the NOTCH3 gene. Family carriers of the same mutation presented with symptoms and imaging abnormalities characteristic of CADASIL. The location of glycine 73 in between C5-C6 disulfide bond of EGF-like domain 1 shows high conservation from humans to zebra fish. It has previously been suggested that the aggregate-prone property of mutant NOTCH3 contributes to a cytotoxic effect in the pathogenic mechanism underlying CADASIL. Here, we investigated the pathogenic mechanism of the new mutation in vitro using HEK293 cells transfected with either a wild-type (WT) or c.218G>C (p.G73A) NOTCH3ECD plasmids, and we found p.G73A NOTCH3ECD was more prone to form aggregation and resistant to degradation. Moreover, the p.G73A NOTCH3ECD compromised cell viability by promoting apoptosis. Two known CADASIL mutants R133C and R75P showed similar results with G73A mutants. Our study here identified G73A as a new mutation in NOTCH3 to cause CADASIL and revealed that the G73A mutation and two known mutants R75P and R133C decreased NOTCH3 protein turnover and induced cell death.

Mitochondrial biogenesis mediated by melatonin in an APPswe/PS1dE9 transgenic mice model.

Alzheimer's disease (AD) is a chronic progressive neurodegenerative disease, but the pathogenesis is unclear. Damaged mitochondrial biogenesis has been observed in AD. Increasing evidence suggests that mitochondrial biogenesis is involved in the pathogenesis of AD, but the exact mechanism is unclear. In this study, we used the amyloid precursor protein Swedish mutations K594N/M595L (APPswe)/presenilin 1 with the exon-9 deletion (PS1dE9) transgenic mouse model of AD, which was successfully established by the expression of amyloid ß precursor protein and presenilin 1 (PS1). Then, we compared APPswe/PS1dE9 transgenic mice with and without melatonin (MT) in drinking water for 4 months (estimated 0.5 mg/day) and control C57BL/6J mice without MT for expression of mitochondrial biogenesis factors (mitochondrial transcription factor A, nuclear respiratory factor 1 and 2, peroxisome proliferator-activated receptor γ coactivator 1-α), mitochondrial structure, mitochondrial DNA to nuclear DNA ratio, behavioral changes, and amyloid ß (Aß) deposition and soluble Aß levels in the cerebral cortex and hippocampus. Compared with controls, APPswe/PS1dE9 mice with long-term MT intake showed increased levels of mitochondrial biogenesis factors, alleviated mitochondrial impairment, enhanced mitochondrial DNA copy number, improved spatial learning and memory deficits, and reduced Aß deposition and soluble Aß levels. Defective mitochondrial biogenesis may contribute toward the damaged mitochondrial structure and function in AD. MT may alleviate AD by promoting mitochondrial biogenesis.