Discovery medicine最新文献

Background: Hypoxia has a major regulatory impact on the electrical activity transmission in the myocardium, and it is involved in the development of tachyarrhythmia disease. Anchor protein G (ankyrin-G, ANK-G) is associated with voltage-gated Na⁺ channels (Nav1.5), but its specific role and mechanism have not been fully defined. In this experiment, we investigated the role and mechanism of hypoxia on cardiomyocyte electrophysiology of voltage-gated Na⁺ channel, as well as the intervention effect of ankyrin-G by simulating the environment of cardiomyocytes during hypoxia through hypoxia-treated murine atrial myocytes (HL-1).

Methods: The HL-1 cells were divided into 6 groups: normoxia group (NO), hypoxia group (HO), ANK-G-overexpressing hypoxia-negative group (ANK-G NC), ANK-G-overexpressing hypoxia group (ANK-G), ANK-G-silenced hypoxia-negative group (shANK-G NC), and ANK-G-silenced hypoxia group (shANK-G). ANK-G overexpression was induced using lentiviral vectors through the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas9 system. The characteristics of sodium ion channel current (I_Na) were observed through the whole-cell patch clamp technique. Western blotting was used to detect the expression of ANK-G and Nav1.5 channel proteins, and the distribution of Nav1.5 channel on HL-1 cells was observed by confocal microscope.

Results: Under hypoxic conditions, the I_Na peak current amplitude (p < 0.01) and density (p < 0.01) of HL-1 cells increased. Compared with the normoxia group, the steady-state inactivation curve of the hypoxia group shifted to the right. The protein levels of ANK-G and Nav1.5 channels were increased under hypoxia (p < 0.001). In the ANK-G group, the upregulation of ANK-G protein increased the distribution of Nav1.5 channel in the cell membrane under the hypoxic condition (p < 0.01).

Conclusions: Hypoxia increases the I_Na amplitude and density of HL-1 cells, and the gating mechanism of I_Na is related to steady-state inactivation. Hypoxic condition triggers the upregulation of the ANK-G protein expression, which promotes the redistribution of Nav1.5 channel proteins in the cell membrane, thereby augmenting I_Na peak current amplitude and density.

Background: Bipolar disorder (BD) is a serious mood disorder, notable for its morbidity and prevalence. It ranks among the top 10 diseases globally in terms of functional impairment among affected individuals. Studies investigating neurobiological processes in the development of BD also aim to identify biological markers. Ubiquitin is a protein that is abundant in all eukaryotic cells and regulates many processes through the ubiquitin-proteasome system. It has been reported to be associated with circadian rhythm and sleep disorders. Circadian rhythm plays a key role in maintaining mood stability in individuals with BD. In this study, we investigated the peripheral levels of molecules involved in the ubiquitination process and their relationship to sleep quality in individuals with BD.

Methods: Forty-nine patients with BD and 50 healthy volunteers without any psychiatric disorders were included. The Pittsburgh Sleep Quality Index, the Young Mania Rating Scale, and the Hamilton Depression Rating Scale were administered to the participants. Peripheral blood levels of proteins and enzymes that play a role in ubiquitination processes were determined by the immunosorbent assay method.

Results: TAR DNA-binding protein-43 (TDP-43) (p < 0.001), ubiquitin C-terminal hydrolase-L1 enzyme (UCH-L1) (p = 0.037), ubiquitin C-terminal hydrolase-L3 enzyme (UCH-L3) (p = 0.007), histone deacetylase I (Histone Dea-1) (p = 0.006), histone deacetylase II (Histone Dea-2) (p = 0.047), and ligase cullin-3 (p = 0.031) levels were found to be significantly lower in the BD group than in the control group, but these parameters were not associated with sleep quality scores in the BD group.

Conclusions: Our results support the data in the literature but show that the ubiquitination process can be affected in BD patients without being associated with sleep quality.

Background: Cardiac fibrosis is a pathophysiological process that occurs as the end stage of cardiovascular diseases. Irisin is a myokine secreted mainly by skeletal muscle exerting pleiotropic effects. Previous studies found altered irisin levels in patients with cardiovascular diseases and irisin has been shown to preserve cardiac function after ischemia-reperfusion injury in mice. This study aimed to explore whether pretreatment with irisin prevents cardiac fibrosis induced in mice through a single injection of the beta-adrenergic agonist isoproterenol at a high dose.

Methods: The cardiac fibrosis model was obtained through a single intraperitoneal administration of 160 mg/kg isoproterenol [ISO] in young C57BL/6J mice. Before ISO injection, mice were pretreated with irisin 100 μg/kg/week [irisin-ISO] or saline [veh-ISO] for 4 weeks. A third group of mice received saline for 4 weeks without ISO injection [CTRL].

Results: The mice pretreated with irisin recovered faster than vehicle-treated mice after acute ISO stimulation, as measured by behavioral test. Twenty-four hours after ISO treatment, the serum levels of Troponin I were significantly lower in the group of mice pretreated with irisin compared with veh-ISO mice (p = 0.0117). Moreover, the expression of atrial natriuretic peptide (p = 0.0197) and alpha-smooth muscle actin (p = 0.0261) mRNAs in cardiac tissue of veh-ISO mice were 10- and 15-fold higher than CTRL mice, respectively, while pretreatment with irisin maintained their expression at control levels. Interestingly, 7 days after ISO, the expression of alpha-smooth muscle actin mRNA was still significantly lower in the irisin-ISO group than in the veh-ISO group (p = 0.0145). Moreover, we found increased cardiac hypertrophy, measured as heart-weight/tibia-length ratio, in veh-ISO mice versus CTRL mice (p = 0.0312) which was fully prevented in irisin-ISO mice (p = 0.0258). The cardiac fibrosis score assessed by Masson's trichrome staining was significantly lower in irisin-ISO mice versus veh-ISO mice (p = 0.0261). Notably, some mitochondrial genes, previously identified as controlled by irisin, were markedly increased in the early phase following ISO, whereas irisin maintained their expression similar to controls.

Conclusion: Our results demonstrate the beneficial effect of irisin in preventing isoproterenol-induced cardiac hypertrophy and fibrosis.

Background: Atrial fibrillation (AF) is a prevalent cardiac arrhythmia associated with increased morbidity and mortality, highlighting the need for novel therapeutic strategies. This study aimed to evaluate the effects of B-type natriuretic peptide (BNP) on cardiac structural remodeling in a rabbit model of AF.

Methods: Rabbits were subjected to rapid pacing to induce an AF model, and BNP was delivered subcutaneously at a dose of 20 μg/kg/d twice per day for three weeks. Electrophysiological measurements were taken to assess the AF induction rate and atrial effective refractory period (AERP), while echocardiographic measurements evaluated left atrial size and function. Histological examinations included hematoxylin and eosin (H&E) staining and Masson's trichrome staining to observe myocardial tissue structure and fibrosis. The ultrastructure of myocardial tissue was observed using a transmission electron microscope.

Results: The study found that BNP treatment significantly reduced the AF induction rate (p < 0.001), improved AERP (p < 0.001), and ameliorated structural and functional changes in the left atrial (p < 0.05). Histological analysis demonstrated decreased myocardial fibrosis post-BNP treatment (p < 0.05). Results also showed that BNP attenuated the cardiomyocyte remodeling caused by AF, as evidenced by significant effects on the expression levels of transforming growth factor-β 1 (TGF-β1), tissue inhibitors of matrix metalloproteinases 1 (TIMP1), matrix metalloproteinase 9 (MMP9), and Collagen I/III (p < 0.05).

Conclusion: These findings suggest that subcutaneous injections of BNP may serve as an effective therapeutic agent in mitigating cardiac structural remodeling in AF, offering significant clinical implications for treating this condition.

High-grade gliomas (HGGs) represent a formidable challenge in neuro-oncology due to their aggressive nature and resistance to current therapeutic interventions, which include surgery, radiation, chemotherapy, and emerging immunotherapies. Despite these efforts, the prognosis for patients remains poor, emphasizing the urgent need for novel treatment strategies. One promising avenue of exploration is microgravity, a condition experienced during spaceflight and simulated in laboratories on Earth, which induces significant physiological changes in cells and tissues. This review synthesizes relevant literature and provides a comprehensive overview of microgravity's effects on glioma cells, encompassing alterations in cell proliferation, apoptosis, gene expression, and a comparative analysis of its impact on other cancer cell types. Studies utilizing simulated microgravity techniques such as clinostats and rotating wall vessels have demonstrated that glioma cells exhibit reduced viability, altered growth patterns, and enhanced activation of apoptotic pathways compared to controls under normal gravity conditions. These findings are significant given the inherent resistance of gliomas to apoptosis; a process critical for the effectiveness of conventional therapies. Despite the challenges in accurately replicating the microgravity environment of space on Earth, simulated microgravity studies have elucidated molecular mechanisms underlying cellular responses. These mechanisms include DNA damage, impaired DNA repair mechanisms, and modulation of apoptotic pathways, which suggest potential vulnerabilities that could be targeted to improve therapeutic outcomes in glioma treatment. Moving forward, further research is essential to deepen our understanding of the specific molecular pathways involved in microgravity-induced effects on glioma cells. This knowledge could pave the way for the development of innovative therapeutic strategies aimed at enhancing apoptosis and overcoming treatment resistance in HGGs. Ultimately, microgravity research offers promising opportunities to advance neuro-oncology by identifying new therapeutic targets and improving clinical outcomes for patients with HHG.

Background: Vitamin D (1,25-(OH)₂D) has been reported to be associated with hyperuricemia in many epidemiologic reports. CYP24A1 is a rate-limiting enzyme involved in vitamin D metabolism. The aim of this study was to investigate the association between the rs6068816 polymorphism in the CYP24A1 gene and hyperuricemia.

Methods: 130 patients with hyperuricemia from the First Affiliated Hospital of Zhengzhou University were included as the case group. 130 subjects without hyperuricemia were selected as the control group to establish a 1:1 matching case-control study. Logistic regression was used to investigate the association between rs6068816 and hyperuricemia. Additionally, multifactor dimensionality reduction analysis was used to further evaluate the interaction of rs6068816 and body mass index.

Results: The results indicated that patients with hyperuricemia had a higher frequency of genotype CT (Odds Ratio (OR): 2.494, 95% Confidence Interval (CI): 1.140-5.454, p = 0.020) and CC (OR: 3.375, 95% CI: 1.500-7.593, p = 0.003) than TT. The mean serum uric acid level for genotype CC was significantly higher than that of genotype TT (p = 0.001). People with genotype CC had a higher risk of developing hyperuricemia than genotype TT (OR: 5.061, 95% CI: 1.582-16.195, p = 0.006). Furthermore, rs6068816 had a significant multiplicative interaction with body mass index. Compared with genotype TT body mass index, CC body mass index displayed a higher risk of hyperuricemia (OR: 11.308, 95% CI: 1.420-90.049, p = 0.022). This interaction was further verified by the multifactor dimensionality reduction model with a cross-validation consistency of 10/10 and testing balanced accuracy of 0.696 (p = 0.044).

Conclusions: Genotype CC of rs6068816 in the CYP24A1 gene is associated with a higher risk of hyperuricemia, especially for overweight people.

Background: Insufficient vitamin D (vit D) levels are associated with various chronic conditions such as cancers, autoimmune diseases, diabetes, and cardiovascular diseases, notably coronary artery disease (CAD). The enzyme 25-hydroxylase, cytochrome P450 2R1 (CYP2R1), catalyzes the hydroxylation of vitamin D in the liver, producing the 25-hydroxyvitamin D, which is then activated in the kidney by cytochrome P450 27B1 (CYP27B1) to form 1,25-dihydroxyvitamin D. Mutations in the CYP2R1 gene can impair vitamin D production. The C-C chemokine receptor type 5 (CCR5) supports endothelial repair and angiogenesis, with its mutation (CCR5 59029 G to A) being linked to insulin resistance and type 2 diabetes (T2D). Additionally, the transcription factor 7-like 2 (TCF7L2), part of the Wnt signaling pathway, regulates glucose homeostasis and the development of tissues, brain, liver and muscles and has been linked to obesity, insulin insensitivity, and elevated blood sugar levels.

Materials and methods: We evaluated the association of reduced serum vitamin D levels with CAD using enzyme-linked immunosorbent assay (ELISA). Genotyping of the CYP2R1 rs1562902 C > T, TCF7L2 rs12255372 G > T, and CCR5 Δ32 bp deletion mutation were performed using amplification-refractory mutation system polymerase chain reaction (PCR) and allele-specific PCR to evaluate their association with CAD risk.

Results: The CYP2R1 rs1562902 C > T single nucleotide polymorphism (SNP) genotypes CT and TT were significantly associated with CAD, with odds ratios (ORs) of 4.1 and 7.6 and p-values of 0.0001 and 0.0008, respectively. The +/Δ genotype of the CCR5 Δ32 bp (ins/del) mutation was also associated with CAD (OR = 2.51, p = 0.006). Additionally, the T allele of the TCF7L2 rs12255372 G > T SNP was linked to an increased risk of CAD (OR = 1.89, p = 0.006).

Conclusion: The CYP2R1 rs1562902 C > T, CCR5 Δ32 (rs333), and TCF7L2 rs12255372 G > T polymorphisms are potential genetic loci associated with increased CAD risk. Furthermore, CYP2R1 variants are associated with vitamin D deficiency, predisposing carriers of CYP2R1 to associated pathologies. These findings warrant further validation through larger case-control studies and functional protein analysis.

Background: Melatonin, a hormone synthesized by the pineal gland and released into the blood, seems to have anti-tumor properties. However, the mechanisms of the anti-cancer effect of melatonin are largely unknown. This study investigated the anti-tumor activity of melatonin in adrenocortical carcinoma (ACC) and analyzed its molecular mechanisms.

Methods: Different concentrations of melatonin were added to ACC cells in vitro and in vivo. Cell viability was appraised via Cell Counting Kit-8 (CCK-8) assay, cell migration and invasion were appraised via wound healing assay and transwell assay, and cell apoptosis was appraised via flow cytometry. The levels of nuclear factor kappa B (NF-κB)/mitogen-activated protein kinase (MAPK) pathway proteins (c-Jun N-terminal kinase (JNK) and p38) and endoplasmic reticulum stress-related proteins (C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78)) were appraised via western blot.

Results: Melatonin reduced the proliferation rate, migration rate, and invasion rate of ACC cells, and significantly increased apoptosis of ACC cells in contrast with the Control Check (CK) group. Moreover, melatonin intervention reduced NF-κB/MAPK signal routing (JNK and p38) and endoplasmic reticulum stress (CHOP and GRP78). Treatment with the NF-κB/MAPK pathway inhibitor NF-κB/MAPK-IN-1 (3.48 μM) enhanced the inhibitory effects of melatonin on the activity of ACC cells and increased apoptosis. The subcutaneous tumor model (SW-13) in nude mice further confirmed that melatonin induced apoptosis of ACC cells by reducing endoplasmic reticulum stress, and NF-κB/MAPK signal routing was involved in this effect.

Conclusion: Melatonin induces apoptosis of ACC cells by reducing endoplasmic reticulum stress, and this effects was may be related to the NF-κB/MAPK signal routing. Melatonin may be an effective anti-tumor agent and have great potential as an adjuvant therapy in the future.

Background: Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is considered highly effective treatment for advanced non-small cell lung cancer (NSCLC), who often develop drug resistance after 10 months of treatment. Herein, the aim was to unravel the mechanism behind the resistance to icotinib in NSCLC.

Methods: Establishment of icotinib-resistant PC-9 cells (PC-9R) was achieved through repeated exposure to increasing concentrations of icotinib for more than 12 months. PC-9R cells were transfected with programmed cell death ligand 1 (PD-L1) knockdown plasmid (PD-L1-KD)/overexpression plasmid (PD-L1-OE), and treated with Wnt pathway agonist CHIR99021 or β-catenin antagonist ICG-001. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium assay was employed for detecting cell sensitivity to icotinib. The invasion and migration abilities of the cells were evaluated using Transwell and scratch assays. Quantification of PD-L1, matrix metalloproteinase (MMP)-2, MMP-9 and Wnt/β-catenin pathway-related proteins was conducted by means of quantitative real-time polymerase chain reaction or Western blotting.

Results: Half-maximal inhibitory concentrations (IC₅₀) of PC-9 and PC-9R cells to icotinib were 1.73 μM and 25.18 μM, respectively. The expression of PD-L1, Wnt family member 1 (Wnt1) and β-catenin was higher in PC-9R cells than in PC-9 cells (p < 0.05). The transfection of PD-L1-OE resulted in elevated IC₅₀, migration, invasion, and MMP-2 and MMP-9 expression in PC-9R cells (p < 0.05), while transfection with PD-L1-KD had the opposite effect (p < 0.05). The expression of PD-L1, β-catenin, MMP-2 and MMP-9, and IC₅₀, migration and invasion was increased following PC-9R cells treatment with CHIR99021 (p < 0.05). These impacts were observed to be in direct contrast in the case of ICG-001 treatment (p < 0.05).

Conclusion: Activation of the Wnt/β-catenin pathway mediates the high expression of PD-L1 to promote the resistance of NSCLC cells to icotinib. Thus, targeted inhibition of PD-L1 expression is of benefit for the treatment of NSCLC.

Neurodegenerative diseases are characterized by progressive damage to specific neuronal cells, resulting in cognitive impairments. Alzheimer's disease is one of the most common types of cognitive impairments. Until recently, strategies that prevent its clinical progression have remained elusive. It has been suggested that oxidative stress, mitochondrial injury, and inflammation might lead to brain cell death in many neurological disorders. Therefore, the identification of effective neuroprotective agents is a research priority, and several autophagy-targeted bioactive compounds are promising candidate therapeutics for the prevention of brain cell damage. Some Alzheimer's disease risk genes expressed within the brain are linked to cholesterol metabolism, lipid transport, endocytosis, exocytosis, and/or caveolae formation, suggesting fruitful therapeutic targets for the treatment of cognitive impairments. Among them, a well-known genetic risk factor for late-onset Alzheimer's disease is allelic variation of the Apolipoprotein E (APOE) genes. APOE proteins may regulate aspects of cellular homeostasis, which is perturbed in the brain in Alzheimer's disease. Interestingly, the Apolipoprotein E ε4 allele (APOE4) protein is related to autophagy and to the biogenesis of caveolae, endosomes, and exosomes, processes which might consequently be involved in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease. Recent research suggests that modification of the diet and/or gut-microbiota could be effective for treatment of various neurodegenerative diseases. Collectively, this research direction has the potential to improve clinical care through disease-modifying treatment strategies with benefits for patients with neurodegenerative diseases.