SREBP-1c impairs ULK1 sulfhydration-mediated autophagic flux to promote hepatic steatosis in high-fat-diet-fed mice.

A metabolic imbalance between lipid synthesis and degradation can lead to hepatic lipid accumulation, a characteristic of patients with non-alcoholic fatty liver disease (NAFLD). Here, we report that high-fat-diet-induced sterol regulatory element-binding protein (SREBP)-1c, a key transcription factor that regulates lipid biosynthesis, impairs autophagic lipid catabolism via altered H2S signaling. SREBP-1c reduced cystathionine gamma-lyase (CSE) via miR-216a, which in turn decreased hepatic H2S levels and sulfhydration-dependent activation of Unc-51-like autophagy-activating kinase 1 (ULK1). Furthermore, Cys951Ser mutation of ULK1 decreased autolysosome formation and promoted hepatic lipid accumulation in mice, suggesting that the loss of ULK1 sulfhydration was directly associated with the pathogenesis of NAFLD. Moreover, silencing of CSE in SREBP-1c knockout mice increased liver triglycerides, confirming the connection between CSE, autophagy, and SREBP-1c. Overall, our results uncover a 2-fold mechanism for SREBP-1c-driven hepatic lipid accumulation through reciprocal activation and inhibition of hepatic lipid biosynthesis and degradation, respectively.

Protective effects of tauroursodeoxycholate against radiation-induced intestinal injury in a mouse model.

In patients with high-level radiation exposure, gastrointestinal injury is the main cause of death. Despite the severity of damage to the gastrointestinal tract, no specific therapeutic option is available. Tauroursodeoxycholic acid (TUDCA) is a conjugated form of ursodeoxycholic acid that suppresses endoplasmic reticulum (ER) stress and regulates various cell-signaling pathways. We investigated the effect of TUDCA premedication in alleviating intestinal damage and enhancing the survival of C57BL/6 mice administered a lethal dose (15Gy) of focal abdominal irradiation. TUDCA was administered to mice 1 h before radiation exposure, and reduced apoptosis of the jejunal crypts 12 h after irradiation. At later timepoint (3.5 days), irradiated mice manifested intestinal morphological changes that were detected via histological examination. TUDCA decreased the inflammatory cytokine levels and attenuated the decrease in serum citrulline levels after radiation exposure. Although radiation induced ER stress, TUDCA pretreatment decreased ER stress in the irradiated intestinal cells. The effect of TUDCA indicates the possibility of radiation therapy for cancer in tumor cells. TUDCA did not affect cell proliferation and apoptosis in the intestinal epithelium. TUDCA decreased the invasive ability of the CT26 metastatic colon cancer cell line. Reduced invasion after TUDCA treatment was associated with decreased matrix metalloproteinase (MMP)-7 and MMP-13 expression, which play important roles in invasion and metastasis. This study shows a potential role of TUDCA in protecting against radiation-induced intestinal damage and inhibiting tumor cell migration without any radiation and radiation therapy effect.

Comparative Morphology of Island and Inland Agastache rugosa and Their Gastroprotective Effects in EtOH/HCl-Induced Gastric Mucosal Gastritis.

Agastache rugosa Kuntze (Lamiaceae; Labiatae), a medicinal and functional herb used to treat gastrointestinal diseases, grows well both on islands and inland areas in South Korea. Thus, we aimed to reveal the morphological and micromorphological differences between A. rugosa grown on island and inland areas and their pharmacological effects on gastritis in an animal model by combining morphological and mass spectrophotometric analyses. Morphological analysis showed that island A. rugosa had slightly smaller plants and leaves than inland plants; however, the density of all types of trichomes on the leaves, petioles, and stems of island A. rugosa was significantly higher than that of inland plants. The essential oil component analysis revealed that pulegone levels were substantially higher in island A. rugosa than in inland A. rugosa. Despite the differences between island and inland A. rugosa, treatment with both island and inland A. rugosa reduced gastric damages by more than 40% compared to the gastritis induction group. In addition, expression of inflammatory protein was reduced by about 30% by treatment of island and inland A. rugosa. The present study demonstrates quantitative differences in morphology and volatile components between island and inland plants; significant differences were not observed between the gastritis-inhibitory effects of island and inland A. rugosa, and the efficacy of island A. rugosa was found to be similar to that of A. rugosa grown in inland areas.

Recent Insights into Hippocampal Dysfunction and Neuroplasticity in Sleep Disorders: An Update from Preclinical Studies.

Sleep disorders are prevalent neurological conditions linked to neurocognitive impairments. Understanding the neuroplasticity changes in the hippocampus, which plays a central role in regulating neurocognitive function, is crucial in the context of sleep disorders. However, research on neurodegenerative disorders and the influence of sleep disorders on hippocampal neuroplasticity remains largely unclear. Therefore, this review aims to highlight the latest advancements regarding hippocampal neuroplasticity and functional changes during sleep disorders, drawing insights from clinical and preclinical research involving sleep-deprived animal models. These articles were gathered through comprehensive literature searches across databases, including Google Scholar, PubMed, Web of Science, and Scopus. Maternal sleep deprivation has been observed to cause neurocognitive impairment in offspring, along with changes in protein expression levels associated with neuroplasticity. Similarly, sleep deprivation in adult mice has been shown to affect several cognitive functions and fear extinction without influencing the acquisition of fear conditioning. While mechanistic research on neurocognitive dysfunction induced by maternal and adult sleep deprivation is limited, it suggests the involvement of several signaling pathways, including neurotrophic factors, synaptic proteins, and inflammatory molecules, which are triggered by sleep deprivation. Further studies are needed to clarify the mechanistic pathways underlying hippocampal dysfunction and synaptic alterations associated with sleep disturbances.

Integrated Genome-Wide Analysis of DNA Methylation and Gene Expression in the Hippocampi of 5xFAD Alzheimer's Disease Mouse Model.

BACKGROUND: DNA methylation forms 5-methylcytosine and its regulation in the hippocampus is critical for learning and memory. Indeed, dysregulation of DNA methylation is associated with neurological diseases. Alzheimer's disease (AD) is the predominant of dementia and a neurodegenerative disorder. METHODS: We examined the learning and memory function in 3- and 9-month-old wild-type and 5xfamiliar Alzheimer's disease (5xFAD) transgenic mice by performing the object recognition memory and Y-maze tests, and identified the hippocampal amyloid beta burden. To investigate the epigenetically regulated genes involved in the development or neuropathology of AD, we performed genome-wide DNA methylation sequencing and RNA sequencing analyses in the hippocampus of 9-month-old wild-type and 5xFAD tg mice. To validate the genes inversely regulated by epigenetics, we confirmed their methylation status and mRNA levels. RESULTS: At 9 months of age, 5xFAD tg mice showed significant cognitive impairment and amyloid-beta plaques in the hippocampus. DNA methylation sequencing identified a total of 13,777 differentially methylated regions, including 4484 of hyper- and 9293 of hypomethylated regions, that are associated with several gene ontology (GO) terms including 'nervous system development' and 'axon guidance'. In RNA sequencing analysis, we confirmed a total of 101 differentially expressed genes, including 52 up- and 49 downregulated genes, associated with GO functions such as 'positive regulation of synaptic transmission, glutamatergic' and 'actin filament organization'. Through further integrated analysis of DNA methylation and RNA sequencing, three epigenetically regulated genes were selected: thymus cell antigen 1, theta (Thy1), myosin VI (Myo6), and filamin A-interacting protein 1-like (Filip1l). The methylation level of Thy1 decreased and its mRNA levels increased, whereas that of Myo6 and Filip1l increased and their mRNA levels decreased. The common functions of these three genes may be associated with the neural cytoskeleton and synaptic plasticity. CONCLUSIONS: We suggest that the candidate genes epigenetically play a role in AD-associated neuropathology (i.e., amyloid-beta plaques) and memory deficit by influencing neural structure and synaptic plasticity. Furthermore, counteracting dysregulated epigenetic changes may delay or ameliorate AD onset or symptoms.

Antiepileptic and Neuroprotective Effects of Rheum tanguticum Root Extract on Trimethyltin-Induced Epilepsy and Neurodegeneration: In Vivo and in Silico Analyses.

BACKGROUND: Rheum tanguticum root, cataloged as "Daehwang" in the Korean Pharmacopeia, is rich in various anthraquinones known for their anti-inflammatory and antioxidant properties. Formulations containing Daehwang are traditionally employed for treating neurological conditions. This study aimed to substantiate the antiepileptic and neuroprotective efficacy of R. tanguticum root extract (RTE) against trimethyltin (TMT)-induced epileptic seizures and hippocampal neurodegeneration. METHODS: The constituents of RTE were identified by ultra-performance liquid chromatography (UPLC). Experimental animals were grouped into the following five categories: control, TMT, and three TMT+RTE groups with dosages of 10, 30, and 100 mg/kg. Seizure severity was assessed daily for comparison between the groups. Brain tissue samples were examined to determine the extent of neurodegeneration and neuroinflammation using histological and molecular biology techniques. Network pharmacology analysis involved extracting herbal targets for Daehwang and disease targets for epilepsy from multiple databases. A protein-protein interaction network was built using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and pivotal targets were determined by topological analysis. Enrichment analysis was performed using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) tool to elucidate the underlying mechanisms. RESULTS: The RTE formulation was found to contain sennoside A, sennoside B, chrysophanol, emodin, physcion, (+)-catechin, and quercetin-3-O-glucuronoid. RTE effectively inhibited TMT-induced seizures at 10, 30, and 100 mg/kg dosages and attenuated hippocampal neuronal decay and neuroinflammation at 30 and 100 mg/kg dosages. Furthermore, RTE significantly reduced mRNA levels of tumor necrosis factor (TNF-α), glial fibrillary acidic protein (GFAP), and c-fos in hippocampal tissues. Network analysis revealed TNF, Interleukin-1 beta (IL-1ß), Interleukin-6 (IL-6), Protein c-fos (FOS), RAC-alpha serine/threonine-protein kinase (AKT1), and Mammalian target of rapamycin (mTOR) as the core targets. Enrichment analysis demonstrated significant involvement of R. tanguticum components in neurodegeneration (p = 4.35 × 10-5) and TNF signaling pathway (p = 9.94 × 10-5). CONCLUSIONS: The in vivo and in silico analyses performed in this study suggests that RTE can potentially modulate TMT-induced epileptic seizures and neurodegeneration. Therefore, R. tanguticum root is a promising herbal treatment option for antiepileptic and neuroprotective applications.

AAV-mediated skeletal muscle specific irisin expression does not contribute to weight loss in mice.

Obesity, a chronic disease, significantly increases the risk of various diseases, including diabetes, cardiovascular diseases, and cancers. Exercise is crucial for weight management not only through energy expenditure by muscle activity but also through stimulating the secretion of myokines, which affect various tissues. Irisin, derived from the proteolytic processing of fibronectin type III domain-containing protein 5 (Fndc5), is a well-studied myokine with beneficial effects on metabolism. This study explored the feasibility of adeno-associated virus (AAV)-mediated Fndc5 gene therapy to treat obesity in a mouse model using the AAV-DIO system to express Fndc5 specifically in skeletal muscle, and investigated its anti-obesity effect. Although Fndc5 was specifically expressed in the muscle, no significant impact on body weight under normal chow or high-fat diets was observed, and no change in thermogenic gene expression in inguinal white adipose tissue was detected. Notably, Fndc5 transduction did affect bone metabolism, consistent with previous reports. These findings suggest that AAV-mediated Fndc5 gene therapy may not be an efficient strategy for obesity, contrary to our expectations. Further research is needed to elucidate the complex mechanisms involved in irisin's role in obesity and related disorders.

Particulate matter exposure and neurodegenerative diseases: A comprehensive update on toxicity and mechanisms.

Exposure to particulate matter (PM) has been associated with a range of health impacts, including neurological abnormalities that affect neurodevelopment, neuroplasticity, and behavior. Recently, there has been growing interest in investigating the possible relationship between PM exposure and the onset and progression of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. However, the precise mechanism by which PM affects neurodegeneration is still unclear, even though several epidemiological and animal model studies have provided mechanistic insights. This article presents a review of the current research on the neurotoxicity of PM and its impact on neurodegenerative diseases. This review summarizes findings from epidemiological and animal model studies collected through searches in Google Scholar, PubMed, Web of Science, and Scopus. This review paper also discusses the reported effects of PM exposure on the central nervous system and highlights research gaps and future directions. The information presented in this review may inform public health policies aimed at reducing PM exposure and may contribute to the development of new treatments for neurodegenerative diseases. Further mechanistic and therapeutic research will be needed to fully understand the relationship between PM exposure and neurodegenerative diseases.

Cold-induced adaptive thermogenesis is impaired by exposure of Asian sand dust in mice.

Desertification and desert sandstorms caused by the worsening global warming pose increasing risks to human health. In particular, Asian sand dust (ASD) exposure has been related to an increase in mortality and hospital admissions for respiratory diseases. In this study, we investigated the effects of ASD on metabolic tissues in comparison to diesel particulate matter (DPM) that is known to cause adverse health effects. We found that larger lipid droplets were accumulated in the brown adipose tissues (BAT) of ASD-administered but not DPM-administered mice. Thermogenic gene expression was decreased in these mice as well. When ASD-administered mice were exposed to the cold, they failed to maintain their body temperature, suggesting that the ASD administration had led to impairments in cold-induced adaptive thermogenesis. However, impaired thermogenesis was not observed in DPM-administered mice. Furthermore, mice fed a high-fat diet that were chronically administered ASD demonstrated unexplained weight loss, indicating that chronic administration of ASD could be lethal in obese mice. We further identified that ASD-induced lung inflammation was not exacerbated in uncoupling protein 1 knockout mice, whose thermogenic capacity is impaired. Collectively, ASD exposure can impair cold-induced adaptive thermogenic responses in mice and increase the risk of mortality in obese mice.

Correction: Song et al. Protective Effect of Resveratrol in an Experimental Model of Salicylate-Induced Tinnitus. Int. J. Mol. Sci. 2022, 23, 14183.

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