DNA methylation modification in Idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and irreversible interstitial lung disease with a prognosis worse than lung cancer. It is a fatal lung disease with largely unknown etiology and pathogenesis, and no effective therapeutic drugs render its treatment largely unsuccessful. With continuous in-depth research efforts, the epigenetic mechanisms in IPF pathogenesis have been further discovered and concerned. As a widely studied mechanism of epigenetic modification, DNA methylation is primarily facilitated by DNA methyltransferases (DNMTs), resulting in the addition of a methyl group to the fifth carbon position of the cytosine base, leading to the formation of 5-methylcytosine (5-mC). Dysregulation of DNA methylation is intricately associated with the advancement of respiratory disorders. Recently, the role of DNA methylation in IPF pathogenesis has also received considerable attention. DNA methylation patterns include methylation modification and demethylation modification and regulate a range of essential biological functions through gene expression regulation. The Ten-Eleven-Translocation (TET) family of DNA dioxygenases is crucial in facilitating active DNA demethylation through the enzymatic conversion of the modified genomic base 5-mC to 5-hydroxymethylcytosine (5-hmC). TET2, a member of TET proteins, is involved in lung inflammation, and its protein expression is downregulated in the lungs and alveolar epithelial type II cells of IPF patients. This review summarizes the current knowledge of pathologic features and DNA methylation mechanisms of pulmonary fibrosis, focusing on the critical roles of abnormal DNA methylation patterns, DNMTs, and TET proteins in impacting IPF pathogenesis. Researching DNA methylation will enchance comprehension of the fundamental mechanisms involved in IPF pathology and provide novel diagnostic biomarkers and therapeutic targets for pulmonary fibrosis based on the studies involving epigenetic mechanisms.

Effect of M2-macrophage treated lymphatic endothelial cells on angiogenesis that promoted osteointegration.

Early vascularization plays an essential role during the whole process in bone regeneration because of the function of secreting cytokines, transporting nutrients and metabolic wastes. As the preliminary basis of bone repair, angiogenesis is regulated by immune cells represented by macrophages to a great extent. However, with the discovery of the endolymphatic circulation system inside bone tissue, the role of vascularization became complicated and confusing. Herein, we developed a macrophage/lymphatic endothelial cells (LECs)/human umbilical vein endothelial cells (HUVECs) co-culture system to evaluate the effect of macrophage treated lymphatic endothelial cells on angiogenesis in vitro and in vivo. In this study, we collected the medium from macrophage (CM) for LECs culture. We found that CM2 could promote the expression of LECs markers and migration ability, which indicated the enhanced lymphogenesis. In addition, the medium from LECs was collected for culturing HUVECs. The CM2-treated LECs showed superior angiogenesis property including the migration capacity and expression of angiogenetic markers, which suggested the superior vascularization. Rat femoral condyle defect model was applied to confirm the hypothesis in vivo. Generally, M2-macrophage treated LECs showed prominent angiogenetic potential coupling with osteogenesis.

Rbpj deletion in hepatic progenitor cells attenuates endothelial responses in a mouse model of cholestatic liver disease.

Background and Aims: Since the role of hepatic progenitor cells (HPCs) constituting ductular reactions in pathogenesis remains ambiguous, we aimed to establish the in vivo cause-and-effect relationship between HPCs and angiogenesis, a process associated with chronic liver disease progression. We previously demonstrated that peritumoral ductules are associated with angiogenesis in liver tumors and forkhead box L1 (Foxl1)- expressing murine HPCs secrete angiogenic factors in vitro. Therefore, we hypothesized that HPCs are capable of remodeling the vascular microenvironment and this function of HPCs is dependent on recombination signal binding protein for immunoglobulin kappa J region (RBPJ), a key effector of the Notch signaling pathway. Approach and Results: We generated HPC-specific Rbpj conditional knockout mice using Foxl1-Cre and treated them with the 3,5-diethoxycarbonyl-1,4-dihydrocollidine-supplemented diet to induce cholestatic liver disease. Knockout mice displayed significant reduction of HPC proliferation and ductular reactions as well as attenuated vascular and fibrotic areas compared to control mice. Assessment of vascular endothelial growth factor A-positive areas in vivo and the effects of Rbpj shRNAs in vitro indicated that Rbpj knockout in HPCs reduces the total number of angiogenic factor-expressing cells rather than affecting angiogenic factor expression within HPCs. Single-nucleus RNA sequencing analysis indicated that conditional Rbpj knockout in HPCs induces transcriptional changes in endothelial cells and alters expression of genes involved in various functions of the endothelium. Conclusion: Our findings indicate that HPCs regulate endothelial responses to cholestatic liver disease and Rbpj deletion in HPCs attenuates these responses, identifying novel targets for modulating angiogenesis during disease progression.

Age Is a Risk Factor for Gastroscopy-Assisted Capsule Endoscopy in Children.

BACKGROUND/AIMS: The aim of this study was to explore the risk factors for the incidence of gastroscopy-assisted capsule endoscopy and the small bowel transit time in pediatric patients who underwent capsule endoscopy examination. MATERIALS AND METHODS: A retrospective analysis was performed to analyze the clinical data collected from pediatric patients who underwent capsule endoscopy examination. RESULTS: A total of 239 pediatric patients were enrolled in this study. About 196 (82.0%) patients completed the entire small bowel capsule endoscopy examination, while 3 (1.3%) patients were subjected to capsule retention. Only age, not gender, height, body weight, body mass index, chief complaint, and intestinal preparation medications, has been identified as a risk factor for the incidence of gastroscopy-assisted capsule endoscopy (P < .05) by multivariate logistic regression. Further analysis showed that the small bowel transit time in the self-swallowed group was shorter than that in the gastroscopy-assisted group, while no significant difference was obtained in other factors, including intestinal preparation medications, metoclopramide, and lesions in the small intestine, which did not significantly affect small bowel transit time compared with the corresponding control group (P > .05). CONCLUSION: A comprehensive assessment is required before performing capsule endoscopy, because age has been identified as a critical risk factor for the incidence of gastroscopy-assisted capsule endoscopy in pediatric patients.

A new spider mite elicitor triggers plant defence and promotes resistance to herbivores.

Herbivore-associated elicitors (HAEs) are active molecules produced by herbivorous insects. Recognition of HAEs by plants induces defence that resist herbivore attacks. We previously demonstrated that the tomato red spider mite Tetranychus evansi triggered defence in Nicotiana benthamiana. However, our knowledge of HAEs from T. evansi remains limited. Here, we characterize a novel HAE, Te16, from T. evansi and dissect its function in mite-plant interactions. We investigate the effects of Te16 on spider mites and plants by heterologous expression, virus-induced gene silencing assay, and RNA interference. Te16 induces cell death, reactive oxygen species (ROS) accumulation, callose deposition, and jasmonate (JA)-related responses in N. benthamiana leaves. Te16-mediated cell death requires a calcium signalling pathway, cytoplasmic localization, the plant co-receptor BAK1, and the signalling components SGT1 and HSP90. The active region of Te16-induced cell death is located at amino acids 114-293. Moreover, silencing Te16 gene in T. evansi reduces spider mite survival and hatchability, but expressing Te16 in N. benthamiana leaves enhances plant resistance to herbivores. Finally, Te16 gene is specific to Tetranychidae species and is highly conserved in activating plant immunity. Our findings reveal a novel salivary protein produced by spider mites that elicits plant defence and resistance to insects, providing valuable clues for pest management.

The transcription factor ELF4 alleviates inflammatory bowel disease by activating IL1RN transcription, suppressing inflammatory TH17 cell activity, and inducing macrophage M2 polarization.

Background: Inflammatory bowel disease (IBD) is a chronic immune-mediated disorder affecting millions worldwide. Due to the complexity of its pathogenesis, the treatment options for IBD are limited. This study focuses on ELF4, a member of the ETS transcription factor family, as a target to elucidate its role in IBD and investigate its mechanism of action in alleviating IBD symptoms by activating IL1RN transcription to suppress the activity of inflammatory TH17 cells. Methods: Using the GEO database, this study examined LPS-induced intestinal inflammatory genes and their regulation mechanisms. We examined the colon length of LPS-treated mice and derived the Disease Activity Index (DAI). H&E staining, ELISA, and flow cytometry were used to detect mice colon tissue damage, inflammatory factor levels in mouse serum, mouse macrophage types and inflammatory TH17 cell activity. RT-qPCR and Western blot detected ELF4, IL1RN, M1, and M2 polarization markers. In Vitro, using dual-luciferase and ChIP assays, we tested mouse bone marrow-derived macrophages (BMDMs) and mouse intestinal epithelial cells for IL1RN promoter activity and ELF4 enrichment. Results: Bioinformatics showed that LPS-induced colitis animals have reduced ELF4 expression in their colon tissue. In vivo tests confirmed reduced ELF4 expression in mice with LPS-induced colitis. ELF4 overexpression reduced mouse intestinal inflammation. ELF4 activated IL1RN transcription in bioinformatics and in vitro tests. ELF4 promoted IL1RN transcription and macrophage M2 polarization to limit intestinal epithelial cell death and inflammation and reduce mouse intestinal inflammation in vitro. ELF4 also reduced the Th17/Treg ratio by increasing IL1RN transcription. Conclusion: ELF4 activates IL1RN transcription, suppresses inflammatory TH17 cells, and induces macrophage M2 polarization to treat IBD.

PIK3R6 Promotes Angiogenesis in Hepatocellular carcinoma by Activating STAT3 Signaling Pathway.

Objective: Abundant angiogenesis in hepatocellular carcinoma (HCC) is critical in its malignant course; however, its mechanism is incompletely understood. Meanwhile, the corresponding roles of PIK3R6 molecules in HCC have not been investigated. This study aims to explore the intrinsic mechanism of PIK3R6 and provide theoretical reference for the treatment of hepatocellular carcinoma. Methods: Differential expressions of PIK in ovarian cancer and normal ones were detected by Western blotting and quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Analyze the relationship between the expression of PIK3R6 and patient prognosis through the TCGA database. Subsequently constructed corresponding stable cell lines, combined with transcriptome sequencing and several cell biology experiments, we explored the inner mechanism and clinical significance of PIK3R6. Results: By analyzing multiple cohorts, we found that high PIK3R6 expression in tumor tissues negatively correlates with patient prognosis. PIK3R6 could increase angiogenesis in HCC by boosting the activity of the STAT3 signalling pathway to hasten the malignant progression of the disease, according to corresponding cellular and molecular experimental studies. Then again, immunohistochemistry on a series of tissue chips confirmed the important clinical significance of PIK3R6-STAT3 regulatory axis. Couclusions: This study initially addressed the clinical significance of PIK3R6 and revealed its mechanism for promoting angiogenesis in hepatocellular carcinoma, providing a reliable working foundation for future in-depth research and clinical translation.

The Mechanism of miR-155/miR-15b Axis Contributed to Apoptosis of CD34+ Cells by Upregulation of PD-L1 in Myelodysplastic Syndromes.

Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal diseases that are characterized by ineffective bone marrow hematopoiesis. Since studies have confirmed the significance of miRNAs in ineffective hematopoiesis in MDS, the current report elucidated the mechanism mediated by miR-155-5p. The bone marrow of MDS patients was collected to detect miR-155-5p and to analyze the correlation between miR-155-5p and clinicopathological variables. Isolated bone marrow CD34+ cells were transfected with lentiviral plasmids that interfere with miR-155-5p, followed by apoptosis analysis. Finally, miR-155-5p-targeted regulation of RAC1 expression was identified, as well as the interaction between RAC1 and CREB, the co-localization of RAC1 and CREB, and the binding of CREB to miR-15b. As measured, miR-155-5p was upregulated in the bone marrow of MDS patients. Further cell experiments validated that miR-155-5p promoted CD34+ cell apoptosis. miR-155-5p could reduce the transcriptional activity of miR-15b by inhibiting RAC1, dissociating the interaction between RAC1 and CREB, and inhibiting the activation of CREB. Upregulating RAC1, CREB, or miR-15b could reduce miR-155-5p-mediated apoptosis promotion on CD34+ cells. Additionally, miR-155-5p could force PD-L1 expression, and this effect was impaired by elevating RAC1, CREB, or miR-15b. In conclusion, miR-155-5p mediates PD-L1-mediated apoptosis of CD34+ cells in MDS by RAC1/CREB/miR-15b axis, thereby inhibiting bone marrow hematopoiesis.

Toxic effects of maternal cadmium exposure on the metabolism and transport system of amino acids in the maternal livers.

Fetal growth restriction (FGR) is one of the most common obstetric diseases, and affects approximately 10 % of all pregnancies worldwide. Maternal cadmium (Cd) exposure is one of the factors that may increase the risk of the development of FGR. However, its underlying mechanisms remain largely unknown. In this study, using Cd-treated mice as an experimental model, we analyzed the levels of some nutrients in the circulation and the fetal livers by biochemical assays; the expression patterns of several key genes involved in the nutrient uptake and transport, and the metabolic changes in the maternal livers were also examined by quantitative real-time PCR and gas chromatography-time of flight-mass spectrometry method. Our results showed that, the Cd treatment specifically reduced the levels of total amino acids in the peripheral circulation and the fetal livers. Concomitantly, Cd upregulated the expressions of three amino acid transport genes (SNAT4, SNAT7 and ASCT1) in the maternal livers. The metabolic profiling of maternal livers also revealed that, several amino acids and their derivatives were also increased in response to the Cd treatment. Further bioinformatics analysis indicated that the experimental treatment activated the metabolic pathways, including the alanine, aspartate and glutamate metabolism, valine, leucine and isoleucine biosynthesis, arginine and proline metabolism. These findings suggest that maternal Cd exposure activate the amino acid metabolism and increase the amino acid uptake in the maternal liver, which reduces the supply of amino acids to the fetus via the circulation. We suspect that this underlies the Cd-evoked FGR.

Structures of human gastrin-releasing peptide receptors bound to antagonist and agonist for cancer and itch therapy.

Gastrin releasing peptide receptor (GRPR), a member of the bombesin (BBN) G protein-coupled receptors, is aberrantly overexpressed in several malignant tumors, including those of the breast, prostate, pancreas, lung, and central nervous system. Additionally, it also mediates non-histaminergic itch and pathological itch conditions in mice. Thus, GRPR could be an attractive target for cancer and itch therapy. Here, we report the inactive state crystal structure of human GRPR in complex with the non-peptide antagonist PD176252, as well as two active state cryo-electron microscopy (cryo-EM) structures of GRPR bound to the endogenous peptide agonist gastrin-releasing peptide and the synthetic BBN analog [D-Phe6, ß-Ala11, Phe13, Nle14] Bn (6-14), in complex with Gq heterotrimers. These structures revealed the molecular mechanisms for the ligand binding, receptor activation, and Gq proteins signaling of GRPR, which are expected to accelerate the structure-based design of GRPR antagonists and agonists for the treatments of cancer and pruritus.

A conserved protein disulfide isomerase enhances plant resistance against herbivores.

Herbivore-associated molecular patterns (HAMPs) enable plants to recognize herbivores and may help plants adjust their defense responses. Here, we report on herbivore-induced changes in a protein disulfide isomerase (PDI) widely distributed across arthropods. PDI from the spider mite Tetranychus evansi (TePDI), a mesophyll-feeding agricultural pest worldwide, triggered immunity in multiple Solanaceae plants. TePDI-mediated cell death in Nicotiana benthamiana required the plant signaling proteins SGT1 (suppressor of the G2 allele of skp1) and HSP90 (heat shock protein 90), but was suppressed by spider mite effectors Te28 and Te84. Moreover, PDIs from phylogenetically distinct herbivorous and nonherbivorous arthropods triggered plant immunity. Finally, although PDI-induced plant defenses impaired the performance of spider mites on plants, RNAi experiments revealed that PDI genes are essential for the survival of mites and whiteflies. Our findings indicate that plants recognize evolutionarily conserved HAMPs to activate plant defense and resist pest damage, pointing to opportunities for broad-spectrum pest management.

miR-34a induces neutrophil apoptosis by regulating Cdc42-WASP-Arp2/3 pathway-mediated F-actin remodeling and ROS production.

BACKGROUND: The number of neutrophils is significantly reduced in myelodysplastic syndrome (MDS), but the molecular basis remains unclear. We recently found that miR-34a was significantly increased in MDS neutrophils. Therefore, this study aims to clarify the effects of aberrant miR-34a expression on neutrophil counts. METHODS: miR-34a mimics/inhibitor transfection were performed in neutrophil-like differentiated HL60 (dHL60) cells, and a FACSCalibur flow cytometer was used to measure ROS production and apoptosis. In addition, the Cdc42-WASP-Arp2/3 pathway inhibitor (ML141) and activator (CN02) treated the dHL60 cells, and then ROS production, apoptosis and related proteins expression were detected. And, luciferase reporter assay to verify the relationship of miR-34a and the Cdc42-WASP-Arp2/3 pathway. RESULTS: overexpression of miR-34a could induce ROS production and apoptosis, decrease the expression levels of DOCK8, p-WASP, WASP, Arp2, Arp3, and increase F-actin's expression. Meanwhile, knockdown of miR-34a could decrease ROS production and apoptosis, increase the expression of DOCK8, p-WASP, WASP, Arp2, Arp3, and decrease F-actin's expression. Immunofluorescence staining showed aberrant miR-34a and Cdc42-WASP-Arp2/3 pathway could induce F-actin membrane transfer. Luciferase reporter assay indicated that DOCK8 was a direct target gene of miR-34a. CONCLUSION: These data indicates miR-34a may induce neutrophil apoptosis by regulating Cdc42-WASP-Arp2/3 pathway-mediated F-actin remodeling and ROS production.

[Activation of JNK induces apoptosis to autophagy conversion and enhances the survival of oxygen-glycogen deprived rat neurons].

Objective To investigate the efficacy and mechanism of c-Jun N-terminal kinase (JNK) in boosting survival of oxygen glucose deprivation (OGD) rat neurons. Methods The cortex neurons from fetal rats were primarily cultured to prepare a model of OGD neurons in vitro, and the characteristic endpoints were filtered to intervene with JNK inducer anisomycin (AN), respectively. The cells were randomly divided into control group, solvent control group (a same volume of solvent DMSO was added into the culture medium of the OGD neuron), AN group (OGD neurons were treated with JNK inducer AN for 5 hours at the end of OGD). After that, Western blotting and immunofluorescence cytometry were respectively performed to detect the protein expressions in OGD neurons, including beclin 1, microtubule-associated protein 1 light chain 3 (LC3), B cell lymphoma 2 (Bcl2), caspase-3, P62, ubiquitin, cathepsin B and lysosomal associated membrane protein 1 (LAMP1). The cell activity was evaluated by CCK-8 assay, and the axon length was measured by IPP software. Results Activation of JNK significantly promoted the expressions of beclin 1, LC3, and Bcl2, and markedly reduced the content of beclin 1-Bcl2 complex and attenuated the expressions of P62 and ubiquitin. Meanwhile, the expressions of cathepsin B and LAMP1 were not obviously altered. In this way, the survival rate of OGD neurons was improved. Conclusion Activation of JNK exerts a neuroprotective effect by facilitating dissociation of beclin 1-Bcl2 and inducing a switch from apoptosis to autophagy in OGD neurons.

Aged bone matrix-derived extracellular vesicles as a messenger for calcification paradox.

Adipocyte differentiation of bone marrow mesenchymal stem/stromal cells (BMSCs) instead of osteoblast formation contributes to age- and menopause-related marrow adiposity and osteoporosis. Vascular calcification often occurs with osteoporosis, a contradictory association called "calcification paradox". Here we show that extracellular vesicles derived from aged bone matrix (AB-EVs) during bone resorption favor BMSC adipogenesis rather than osteogenesis and augment calcification of vascular smooth muscle cells. Intravenous or intramedullary injection of AB-EVs promotes bone-fat imbalance and exacerbates Vitamin D3 (VD3)-induced vascular calcification in young or old mice. Alendronate (ALE), a bone resorption inhibitor, down-regulates AB-EVs release and attenuates aging- and ovariectomy-induced bone-fat imbalance. In the VD3-treated aged mice, ALE suppresses the ovariectomy-induced aggravation of vascular calcification. MiR-483-5p and miR-2861 are enriched in AB-EVs and essential for the AB-EVs-induced bone-fat imbalance and exacerbation of vascular calcification. Our study uncovers the role of AB-EVs as a messenger for calcification paradox by transferring miR-483-5p and miR-2861.

Celiac disease may be rare among children in South China.

OBJECTIVE: The prevalence of celiac disease (CD) varies geographically and ethnically; however, the prevalence among children in South China remains unknown. We therefore determined the occurrence of CD among Chinese children in South China. METHODS: Serum samples were collected from children and assessed for anti-tissue transglutaminase IgA antibodies (anti-tTG-IgA) and total IgA. Anti-tTG-IgA+ participants underwent human leukocyte antigen (HLA) DQ2/DQ8 determination. Samples with serum total IgA <0.05 g/L were also analyzed for anti-tTG-IgG, and for HLA-DQ2/DQ8 if the values were above borderline. Participants who were anti-tTG-IgA/IgG+ and HLA-DQ2+ and/or HLA-DQ8+ underwent small bowel biopsy. RESULTS: A total of 8794 children were enrolled, of whom 479 had chronic unexplained abdominal symptoms. Three (0.034%) children were anti-tTG-IgA+ and ten (0.114%) had serum total IgA <0.05 g/L, all of whom were anti-tTG-IgG-. The three positive children were all HLA-DQ2+ and/or HLA-DQ8+. Two underwent gastroscopy, and histopathology of small intestinal biopsy showed duodenal villous blunting in one and increased intraepithelial lymphocytes in the other, neither consistent with a diagnosis of CD. CONCLUSION: Our study showed a prevalence of CD autoimmunity of 0.034% and failed to identify any cases of CD, suggesting a low prevalence of CD among children in South China.

Impaired intestinal stem cell activity in ETEC infection: enterotoxins, cyclic nucleotides, and Wnt signaling.

Enterotoxigenic Escherichia coli (ETEC) in humans and animals colonizes the intestine and thereafter secrets heat-stable enterotoxin (ST) with or without heat-labile enterotoxin (LT), which triggers massive fluid and electrolyte secretion into the gut lumen. The crosstalk between the cyclic nucleotide-dependent protein kinase/cystic fibrosis transmembrane conductance regulator (cAMP or cGMP/CFTR) pathway involved in ETEC-induced diarrhea channels, and the canonical Wnt/ß-catenin signaling pathway leads to changes in intestinal stem cell (ISC) fates, which are strongly associated with developmental disorders caused by diarrhea. We review how alterations in enterotoxin-activated ion channel pathways and the canonical Wnt/ß-catenin signaling pathway can explain inhibited intestinal epithelial activity, characterize alterations in the crosstalk of cyclic nucleotides, and predict harmful effects on ISCs in targeted therapy. Besides, we discuss current deficits in the understanding of enterotoxin-intestinal epithelial cell activity relationships that should be considered when interpreting sequelae of diarrhea.

Disruption of protein quality control of the human ether-à-go-go related gene K+ channel results in profound long QT syndrome.

BACKGROUND: Long QT syndrome (LQTS) is a hereditary disease that predisposes patients to life-threatening cardiac arrhythmias and sudden cardiac death. Our previous study of the human ether-à-go-go related gene (hERG)-encoded K+ channel (Kv11.1) supports an association between hERG and RING finger protein 207 (RNF207) variants in aggravating the onset and severity of LQTS, specifically T613M hERG (hERGT613M) and RNF207 frameshift (RNF207G603fs) mutations. However, the underlying mechanistic underpinning remains unknown. OBJECTIVE: The purpose of the present study was to test the role of RNF207 in the function of hERG-encoded K+ channel subunits. METHODS: Whole-cell patch-clamp experiments were performed in human embryonic kidney (HEK 293) cells and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) together with immunofluorescent confocal and high resolution microscopy, auto-ubiquitinylation assays, and co-immunoprecipitation experiments to test the functional interactions between hERG and RNF207. RESULTS: Here, we demonstrated that RNF207 serves as an E3 ubiquitin ligase and targets misfolded hERGT613M proteins for degradation. RNF207G603fs exhibits decreased activity and hinders the normal degradation pathway; this increases the levels of hERGT613M subunits and their dominant-negative effect on the wild-type subunits, ultimately resulting in decreased current density. Similar findings are shown for hERGA614V, a known dominant-negative mutant subunit. Finally, the presence of RNF207G603fs with hERGT613M results in significantly prolonged action potential durations and reduced hERG current in human-induced pluripotent stem cell-derived cardiomyocytes. CONCLUSION: Our study establishes RNF207 as an interacting protein serving as a ubiquitin ligase for hERG-encoded K+ channel subunits. Normal function of RNF207 is critical for the quality control of hERG subunits and consequently cardiac repolarization. Moreover, our study provides evidence for protein quality control as a new paradigm in life-threatening cardiac arrhythmias in patients with LQTS.

Vascular Smooth Muscle Cells in Aortic Aneurysm: From Genetics to Mechanisms.

Aortic aneurysm, including thoracic aortic aneurysm and abdominal aortic aneurysm, is the second most prevalent aortic disease following atherosclerosis, representing the ninth-leading cause of death globally. Open surgery and endovascular procedures are the major treatments for aortic aneurysm. Typically, thoracic aortic aneurysm has a more robust genetic background than abdominal aortic aneurysm. Abdominal aortic aneurysm shares many features with thoracic aortic aneurysm, including loss of vascular smooth muscle cells (VSMCs), extracellular matrix degradation and inflammation. Although there are limitations to perfectly recapitulating all features of human aortic aneurysm, experimental models provide valuable tools to understand the molecular mechanisms and test novel therapies before human clinical trials. Among the cell types involved in aortic aneurysm development, VSMC dysfunction correlates with loss of aortic wall structural integrity. Here, we discuss the role of VSMCs in aortic aneurysm development. The loss of VSMCs, VSMC phenotypic switching, secretion of inflammatory cytokines, increased matrix metalloproteinase activity, elevated reactive oxygen species, defective autophagy, and increased senescence contribute to aortic aneurysm development. Further studies on aortic aneurysm pathogenesis and elucidation of the underlying signaling pathways are necessary to identify more novel targets for treating this prevalent and clinical impactful disease.

Yixin-Fumai granules improve sick sinus syndrome in aging mice through Nrf-2/HO-1 pathway: A new target for sick sinus syndrome.

ETHNOPHARMACOLOGICAL RELEVANCE: Yixin-Fumai granules (YXFMs)-composed of Ginseng quinquefolium (L.) Alph. Wood, Ophiopogon japonicus (Thunb.) Ker Gawl, Schisandra arisanensis Hayata, Astragalus aaronsohnianus Eig, Salvia cryptantha Montbret & Aucher ex Benth, and Ligusticum striatum DC-are compound granules used in traditional Chinese medicine to increase heart rate and thus treat bradyarrhythmia. It may be effective in treating sick sinus syndrome (SSS). AIM: To observe the effect of YXFMs on aging-induced SSS in mice and explore whether this effect is related to the Nrf-2/HO-1 signaling pathway. MATERIALS AND METHODS: Mice with a significant decrease in the heart rate due to natural aging were selected to construct an SSS model. After the mice were administered YXFMs, the damage to their sinoartrial node (SAN) was assessed through electrocardiography, Masson's trichrome staining, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Dihydroethidium staining and immunofluorescence staining were used to assay reactive oxygen species (ROS) content and HCN4, respectively. Moreover, to observe the effects of YXFMs in vitro, the HL-1 cell line, derived from mouse atrial myocytes, was used to simulate SAN pacemaker cells, with H2O2 used as the cellular oxidative stress (OS) inducer. 2,7-Dichlorodihydrofluorescein diacetate staining was used to assay ROS content, whereas immunofluorescence staining and Western blotting were used to elucidate the related protein expression. Finally, mice were injected the Nrf-2 inhibitor ML385 to reversely verify the effects of YXFMs. RESULTS: In our in vivo experiments, YXFMs significantly inhibited aging-induced SSS, shortened the R-R interval, increased heart rate, alleviated fibrosis, reduced apoptosis rate and ROS content, and promote HCN4 expression in the SAN. In our in vitro experiments, YXFMs significantly inhibited H2O2-induced cell peroxidation damage, promoted Nrf-2 activation and nuclear metastasis, increased HO-1 expression- thereby inhibiting ROS accumulation-and finally, upregulated HCN4 expression through the inhibition of histone deacetylase 4 (HDAC4) expression and its nuclear metastasis. Finally, injection of the Nrf-2 inhibitor ML385 after YXFMs administration inhibited their protective effect in the mice. CONCLUSION: Here, we elaborated on the relationship between aging-induced SSS and the Nrf-2/HO-1 pathway for the first time and proposed that YXFMs improve SSS via the Nrf-2/HO-1 axis. Specifically, YXFMs promoted Nrf-2 activation and plasma-nuclear transfer to enhance HO-1 expression via the Nrf-2/HO-1 axis. This inhibited OS and reduced ROS accumulation in the SAN, and then, through the ROS/HDAC4 axis, reduced HDAC4 expression and plasma-nuclear transfer. Thereby, the OS-induced HCN4 loss in the SAN was inhibited-improving the function of If channel and thus producing SAN protection effect against SSS and improving the heart rate and R-R interval. In the future, we plan to use bioinformatics analysis technology to execute the next step of our research, namely to determine the effect of isolated, purified components of YXFMs in SSS, to increase its efficiency and reduce the toxicity of YXFMs.