Metabolic landscape of human alveolar type II epithelial cells undergoing epithelial-mesenchymal transition induced directly by silica exposure.

Epithelial-mesenchymal transition (EMT) plays an irreplaceable role in the development of silicosis. However, molecular mechanisms of EMT induced by silica exposure still remain to be addressed. Herein, metabolic profiles of human alveolar type II epithelial cells (A549 cells) exposed directly to silica were characterized using non-targeted metabolomic approaches. A total of 84 differential metabolites (DMs) were identified in silica-treated A549 cells undergoing EMT, which were mainly enriched in metabolisms of amino acids (e.g., glutamate, alanine, aspartate), purine metabolism, glycolysis, etc. The number of DMs identified in the A549 cells obviously increased with the elevated exposure concentration of silica. Remarkably, glutamine catabolism was significantly promoted in the silica-treated A549 cells, and the levels of related metabolites (e.g., succinate) and enzymes (e.g., α-ketoglutarate (α-KG) dehydrogenase) were substantially up-regulated, with a preference to α-KG pathway. Supplementation of glutamine into the cell culture could substantially enhance the expression levels of both EMT-related markers and Snail (zinc finger transcription factor). Our results suggest that the EMT of human alveolar epithelial cells directly induced by silica can be essential to the development of silicosis.

Hyaluronic acid-mediated epithelial-mesenchymal transition of human lens epithelial cells via CD44 and TGF-β2

ABSTRACT Purpose: The epithelial-mesenchymal transition of human lens epithelial cells plays a role in posterior capsule opacification, a fibrotic process that leads to a common type of cataract. Hyaluronic acid has been implicated in this fibrosis. Studies have investigated the role of transforming growth factor (TGF)-β2 in epithelial-mesenchymal transition. However, the role of TGF-β2 in hyaluronic acid-mediated fibrosis of lens epithelial cell remains unknown. We here examined the role of TGF-β2 in the hyaluronic acid-mediated epithelial-mesenchymal transition of lens epithelial cells. Methods: Cultured human lens epithelial cells (HLEB3) were infected with CD44-siRNA by using the Lipofectamine 3000 transfection reagent. The CCK-8 kit was used to measure cell viability, and the scratch assay was used to determine cell migration. Cell oxidative stress was analyzed in a dichloro-dihydro-fluorescein diacetate assay and by using a flow cytometer. The TGF-β2 level in HLEB3 cells was examined through immunohistochemical staining. The TGF-β2 protein level was determined through western blotting. mRNA expression levels were determined through quantitative real-time polymerase chain reaction. Results: Treatment with hyaluronic acid (1.0 μM, 24 h) increased the epithelial-mesenchymal transition of HLEB3 cells. The increase in TGF-β2 levels corresponded to an increase in CD44 levels in the culture medium. However, blocking the CD44 function significantly reduced the TGF-β2-mediated epithelial-mesenchymal transition response of HLEB3 cells. Conclusions: Our study showed that both CD44 and TGF-β2 are critical contributors to the hyaluronic acid-mediated epithelial-mesenchymal transition of lens epithelial cells, and that TGF-β2 in epithelial-mesenchymal transition is regulated by CD44. These results suggest that CD44 could be used as a target for preventing hyaluronic acid-induced posterior capsule opacification. Our findings suggest that CD44/TGF-β2 is crucial for the hyaluronic acid-induced epithelial-mesenchymal transition of lens epithelial cells.

Integrin subunit beta 6 is a potential diagnostic marker for acute kidney injury in patients with diabetic kidney disease: a single cell sequencing data analysis.

BACKGROUND: Diabetic kidney disease (DKD), a prevalent complication of diabetes mellitus, is often associated with acute kidney injury (AKI). Thus, the development of preventive and therapeutic strategies is crucial for delaying the progression of AKI and DKD. METHODS: The GSE183276 dataset, comprising the data of 20 healthy controls and 12 patients with AKI, was downloaded from the Gene Expression Omnibus (GEO) database to analyze the AKI group. For analyzing the DKD group, the GSE131822 dataset, comprising the data of 3 healthy controls and 3 patients with DKD, was downloaded from the GEO database. The common differentially expressed genes (DEGs) in renal tubular epithelial cells (TECs) were subjected to enrichment analyses. Next, a protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes database to analyze gene-related regulatory networks. Finally, the AKI animal models and the DKD and AKI cell models were established, and the reliability of the identified genes was validated using quantitative real-time polymerase chain reaction analysis. RESULTS: Functional analysis was performed with 40 common DEGs in TECs. Eight hub genes were identified using the PPI and gene-related networks. Finally, validation experiments with the in vivo animal model and the in vitro cellular model revealed the four common DEGs. Four DEGs that share molecular mechanisms in the pathogenesis of DKD and AKI were identified. In particular, the expression of Integrin Subunit Beta 6(ITGB6), a hub and commonly upregulated gene, was upregulated in the in vitro models. CONCLUSION: ITGB6 may serve as a biomarker for early AKI diagnosis in patients with DKD and as a target for early intervention therapies.

Maternal stress and the early embryonic microenvironment: investigating long-term cortisol effects on bovine oviductal epithelial cells using air-liquid interface culture.

The oviduct epithelium is the initial maternal contact site for embryos after fertilization, offering the microenvironment before implantation. This early gestation period is particularly sensitive to stress, which can cause reduced fertility and reproductive disorders in mammals. Nevertheless, the local impact of elevated stress hormones on the oviduct epithelium has received limited attention to date, except for a few reports on polyovulatory species like mice and pigs. In this study, we focused on the effects of chronic maternal stress on cattle, given its association with infertility issues in this monoovulatory species. Bovine oviduct epithelial cells (BOEC) differentiated at the air-liquid interface (ALI) were stimulated with 250 nmol/L cortisol for 1 or 3 weeks. Subsequently, they were assessed for morphology, bioelectrical properties, and gene expression related to oviduct function, glucocorticoid pathway, cortisol metabolism, inflammation, and apoptosis. Results revealed adverse effects of cortisol on epithelium structure, featured by deciliation, vacuole formation, and multilayering. Additionally, cortisol exposure led to an increase in transepithelial potential difference, downregulated mRNA expression of the major glucocorticoid receptor (NR3C1), upregulated the expression of cortisol-responsive genes (FKBP5, TSC22D3), and significant downregulation of oviductal glycoprotein 1 (OVGP1) and steroid receptors PGR and ESR1. The systematic comparison to a similar experiment previously performed by us in porcine oviduct epithelial cells, indicated that bovine cultures were more susceptible to elevated cortisol levels than porcine. The distinct responses between both species are likely linked to their divergence in the cortisol-induced expression changes of HSD11B2, an enzyme controlling the cellular capacity to metabolise cortisol. These findings provide insights into the species-specific reactions and reproductive consequences triggered by maternal stress.

Suppressive effects of Toll-Like Receptor 2, Toll-Like Receptor 4, and Toll-Like Receptor 7 on protective responses to Mycobacterium bovis BCG from epithelial cells.

Mycobacteria have several mechanisms for evasion of protective responses mounted by the host. In this study, we unravel yet another mechanism that is mediated by Toll-Like Receptors TLR2, TLR4, and TLR7 in epithelial cells. We show that mycobacterial infection of epithelial cells increases the expression of TLR2, TLR4, and TLR7. Stimulation of either TLR along with mycobacterial infection results in an inhibition of oxidative burst resulting in increased survival of mycobacteria inside epithelial cells. TLR stimulation along with mycobacterial infection also inhibits activation of epithelial cells for T cell responses by differentially regulating the activation of ERK-MAPK and p38-MAPK along with inhibition of co-stimulatory molecule CD86 expression. Furthermore, stimulation of either TLR inhibits the induction of apoptosis and autophagy. Knockdown of either TLR by specific siRNAs reverses the inhibition by ROS and apoptosis by mycobacteria and results in reduced intracellular survival of mycobacteria in a MyD88-dependent manner. These results point towards a negative role for TLR2, TLR4, and TLR7 in regulating protective responses to M. bovis BCG infection in epithelial cells.

The Scribble/SGEF/Dlg1 complex regulates E-cadherin and ZO-1 stability, turnover, and transcription in epithelial cells.

SGEF, a RhoG specific GEF, can form a ternary complex with the Scribble polarity complex proteins Scribble and Dlg1, which regulates the formation and maintenance of adherens junctions and barrier function of epithelial cells. Notably, silencing SGEF results in a dramatic downregulation of both E-cadherin and ZO-1 protein levels. However, the molecular mechanisms involved in the regulation of this pathway are not known. Here, we describe a novel signaling pathway governed by the Scribble/SGEF/Dlg1 complex. Our results show that the three members of the ternary complex are required to maintain the stability of the apical junctions, ZO-1 protein levels, and TJ permeability. In contrast, only SGEF is necessary to regulate E-cadherin levels. The absence of SGEF destabilizes the E-cadherin/catenin complex at the membrane, triggering a positive feedback loop that exacerbates the phenotype through the repression of E-cadherin transcription in a process that involves the internalization of E-cadherin by endocytosis, ß-catenin signaling and the transcriptional repressor Slug.

Single-cell RNA sequencing data locate ALDH1A2-mediated retinoic acid synthetic pathway to glomerular parietal epithelial cells.

Aldehyde dehydrogenase 1, family member A2, is a retinoic acid-synthesizing enzyme encoded by Aldh1a2 in mice and ALDH1A2 in humans. This enzyme is indispensable for kidney development, but its role in kidney physiology and pathophysiology remains to be fully defined. In this review, we mined single-cell and single-nucleus RNA sequencing databases of mouse and human kidneys and found that glomerular parietal epithelial cells (PECs) express a full set of genes encoding proteins needed for cellular vitamin A uptake, intracellular transport, and metabolism into retinoic acid. In particular, Aldh1a2/ALDH1A2 mRNAs are selectively enriched in mouse and human PECs. Aldh1a2 expression in PECs is greatly increased in a mouse model of anti-glomerular basement membrane glomerulonephritis and moderately induced in a mouse model of ischemia-reperfusion acute kidney injury. Aldh1a2 expression in PECs is substantially repressed in a chronic kidney disease mouse model combining diabetes, hypertension, and partial nephrectomy and is moderately repressed in mouse models of focal segmental glomerulosclerosis and diabetic nephropathy. Single-nucleus RNA sequencing data show that ALDH1A2 mRNA expression in PECs is diminished in patients with chronic kidney disease associated with diabetes, hypertension and polycystic kidney disease. In addition to data mining, we also performed Spearman's rank correlation coefficient analyses and identified gene transcripts correlated with Aldh1a2/ALDH1A2 transcripts in mouse PECs and PEC subtypes, and in human PECs of healthy subjects and patients with AKI or CKD. Furthermore, we conducted Gene Ontology pathway analyses and identified the biological pathways enriched among these Aldh1a2/ALDH1A2-correlated genes. Our data mining and analyses led us to hypothesize that ALDH1A2-mediated retinoic acid synthesis in PECs plays a yet-undefined role in the kidney and that its dysregulation mediates injury. Conditional, PEC-selective Aldh1a2 knockout, RNA silencing and transgenic mouse models will be useful tools to test this hypothesis. Clinical studies on genetics, epigenetics, expression and functions of ALDH1A2 and other genes needed for retinoic acid biosynthesis and signaling are also warranted.

Androgens have therapeutic potential in T2 asthma by mediating METTL3 in bronchial epithelial cells.

Studies have shown that androgens can alleviate the symptoms of T2 asthma and are inversely correlated with the severity of allergic asthma. METTL3, a crucial component of m6A modification, mitigates the development of T2 asthma by inhibiting Th2 cell differentiation. However, the impact of androgens, such as dihydrotestosterone (DHT), on the progression of T2 asthma through METTL3 has yet to be investigated. At the clinical level, patients with T2 asthma exhibited reduced levels of DHT and METTL3 mRNA, along with increased levels of 17ß-estradiol (E2). DHT and METTL3 were found to be negatively associated with the severity of T2 asthma, while E2 was positively associated with it. Administration of DHT and E2 in induced T2 asthma mouse models showed that DHT improved lung function, reduced airway inflammation, and inhibited Th2 cell differentiation. Interestingly, DHT reversed the damage to METTL3, whereas E2 had the opposite effect. In vitro studies of mouse bronchial epithelial cells (BECs) confirmed that METTL3-dependent m6A modification inhibited the T2 inflammatory response, and DHT inhibited Th2 cell differentiation in T2 asthma by promoting METTL3 expression in BECs. In conclusion, our study suggests that DHT has therapeutic potential for T2 asthma by regulating METTL3 in BECs.

Topical Application of Dexamethasone-Loaded Core-Multishell Nanocarriers Against Oral Mucosal Inflammation.

Topical treatment of oral inflammatory diseases is challenging due to the intrinsic physicochemical barriers of the mucosa and the continuous flow of saliva, which dilute drugs and limit their bioavailability. Nanocarrier technology can be an innovative approach to circumvent these problems and thus improve the efficacy of topical drug delivery to the mucosa. Core-multishell (CMS) nanocarriers are putative delivery systems with high biocompatibility and the ability to adhere to and penetrate the oral mucosa. Ester-based CMS nanocarriers release the anti-inflammatory compound dexamethasone (Dx) more efficiently than a conventional cream. Mussel-inspired functionalization of a CMS nanocarrier with catechol further improves the adhesion of the nanocarrier and may enhance the efficacy of the loaded drugs. In the present study, the properties of the ester-based CMS 10-E-15-350 nanocarrier (CMS-NC) are further evaluated in comparison to the catechol-functionalized variant (CMS-C0.08). While the mucoadhesion of CMS-NC is inhibited by saliva, CMS-C0.08 exhibits better mucoadhesion in the presence of saliva. Due to the improved adhesion properties, CMS-C0.08 loaded with dexamethasone (Dx-CMS-C0.08) shows a better anti-inflammatory effect than Dx-CMS-NC when applied dynamically. These results highlight the superiority of CMS-C0.08 over CMS-NC as an innovative drug delivery system (DDS) for the treatment of oral mucosal diseases.

Mechanism of collagen type IV regulation by focal adhesion kinase during retained fetal membranes in dairy cows.

Retained fetal membranes (RFM) is an important reproductive disease in dairy cows, caused by maternal and fetal placental tissue adhesion. The main collagen in maternal and fetal placenta tissues is collagen type IV (COL-IV) and its breakdown is the key to placental expulsion. Focal adhesion kinase (FAK) has been shown to regulate the hydrolysis of Col-IV by affecting the activity of MMP-2 and MMP-9 activity, but the regulation of the mechanisms involved in placenta expulsion in dairy cows after postpartum are still unclear. The aim of this study was to investigate the pathogenic mechanism of RFM by studying the relationship between the FAK signaling pathway and COL-IV regulation. Maternal placental tissues were collected from six healthy and six cows with RFM of similar age, parity, body condition and milk yield at 12 h postpartum. In vitro experiments were performed on bovine endometrial epithelial cells from three groups including a FAK inhibitor group, a FAK activator group and a control group without FAK inhibitor and activator. The abundance of molecules involved in the FAK signaling pathway and COL-IV was detected by immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. The immunohistochemical results showed that the key molecules of FAK signaling pathway FAK, Src, MMP-2 and MMP-9 and Col-IV were expressed in placental tissues. The expression level of FAK, Src, MMP-2, and MMP-9 were significantly down-regulated (P < 0.05) and the abundances of COL-IV were significantly up-regulated (P < 0.05) in maternal placental tissues of RFM cows compared with healthy cows. In the FAK inhibitor treatment group, the relative expression levels of FAK and other related proteins were significantly down-regulated (P < 0.05) and the relative expression levels of COL-IV were significantly up-regulated (P < 0.05) with the results of the FAK activation group the opposite. These results indicated that FAK in maternal endometrial epithelial cells could regulate the hydrolysis process of Col-IV through the expression of key factors of signaling pathways and promote collagen hydrolysis, which in turn facilitated the process of postpartum placenta expulsion in dairy cows.

The soluble factor milieu in idiopathic pulmonary fibrosis dysregulates epithelial differentiation.

In idiopathic pulmonary fibrosis (IPF), epithelial abnormalities are present including bronchiolization and alveolar cell dysfunction. We hypothesized that the IPF microenvironment disrupts normal epithelial growth and differentiation. We mimicked the soluble factors within an IPF microenvironment using an IPF cocktail (IPFc), composed of nine factors which are increased in IPF lungs (CCL2, IL-1ß, IL-4, IL-8, IL-13, IL-33, TGF-ß, TNFα, and TSLP). Using IPFc, we asked whether the soluble factor milieu in IPF affects epithelial growth and differentiation and how IPFc compares to TGF-ß alone. Epithelial growth and differentiation were studied using mouse lung organoids (primary Epcam+ epithelial cells co-cultured with CCL206 fibroblasts). Organoids exposed to IPFc and TGF-ß were re-sorted into epithelial and fibroblast fractions and subjected to RNA sequencing. IPFc did not affect the number of organoids formed. However, pro-surfactant protein C expression was decreased. On these parameters, TGF-ß alone had similar effects. However, RNA sequencing of re-sorted organoids revealed that IPFc and TGF-ß had distinct effects on both epithelial cells and fibroblasts. IPFc upregulated goblet cell markers, whereas these were inhibited by TGF-ß. Although both IPFc and TGF-ß increased extracellular matrix gene expression, only TGF-ß increased myofibroblast markers. VEGF-C and Wnt signaling were among the most differentially regulated signaling pathways by IPFc versus TGF-ß. Interestingly, Wnt pathway activation rescued Sftpc downregulation induced by IPFc. In conclusion, IPFc alters epithelial differentiation in a way that is distinct from TGF-ß. Alterations in Wnt signaling contribute to these effects. IPFc may be a more comprehensive representation of the soluble factor microenvironment in IPF.

Distinct Responses of Cystic Fibrosis Epithelial Cells to SARS-CoV-2 and Influenza A Virus.

The COVID-19 pandemic has underscored the impact of viral infections on individuals with cystic fibrosis (CF). Initial observations suggested lower COVID-19 rates among CF populations; however, subsequent clinical data have presented a more complex scenario. This study aimed to investigate how bronchial epithelial cells from CF and non-CF individuals, including various CF transmembrane conductance regulator (CFTR) mutations, respond to in vitro infection with SARS-CoV-2 variants and SARS-CoV. Comparisons with the Influenza A virus (IAV) were included based on evidence that CF patients experience heightened morbidity from IAV infection. Our findings showed that CF epithelial cells exhibited reduced replication of SARS-CoV-2, regardless of the type of CFTR mutation or SARS-CoV-2 variant, as well as the original 2003 SARS-Cove. In contrast, these cells displayed more efficient IAV replication compared to non-CF cells. Interestingly, the reduced susceptibility to SARS-CoV-2 in CF was not linked to the expression of angiotensin converting enzyme 2 (ACE2) receptor nor to CFTR dysfunction, as pharmacological treatments to restore CFTR function did not normalize the viral response. Both SARS-CoV-2 infection and CFTR function influenced the levels of certain cytokines and chemokines, although these effects were not correlated. Overall, this study reveals a unique viral response in CF epithelial cells, characterized by reduced replication for some viruses like SARS-CoV-2, while showing increased susceptibility to others such as IAV. This research offers a new perspective on CF and viral interactions, emphasizing the need for further investigation into the mechanisms underlying these differences. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Deep learning for rapid analysis of cell divisions in vivo during epithelial morphogenesis and repair.

Cell division is fundamental to all healthy tissue growth, as well as being rate-limiting in the tissue repair response to wounding and during cancer progression. However, the role that cell divisions play in tissue growth is a collective one, requiring the integration of many individual cell division events. It is particularly difficult to accurately detect and quantify multiple features of large numbers of cell divisions (including their spatio-temporal synchronicity and orientation) over extended periods of time. It would thus be advantageous to perform such analyses in an automated fashion, which can naturally be enabled using deep learning. Hence, we develop a pipeline of deep learning models that accurately identify dividing cells in time-lapse movies of epithelial tissues in vivo. Our pipeline also determines their axis of division orientation, as well as their shape changes before and after division. This strategy enables us to analyse the dynamic profile of cell divisions within the Drosophila pupal wing epithelium, both as it undergoes developmental morphogenesis and as it repairs following laser wounding. We show that the division axis is biased according to lines of tissue tension and that wounding triggers a synchronised (but not oriented) burst of cell divisions back from the leading edge.

The Nuclear NF-κB Regulator IκBζ: Updates on Its Molecular Functions and Pathophysiological Roles.

More than a decade after the discovery of the classical cytoplasmic IκB proteins, IκBζ was identified as an additional member of the IκB family. Unlike cytoplasmic IκB proteins, IκBζ has distinct features, including its nuclear localization, preferential binding to NF-κB subunits, unique expression properties, and specialized role in NF-κB regulation. While the activation of NF-κB is primarily controlled by cytoplasmic IκB members at the level of nuclear entry, IκBζ provides an additional layer of NF-κB regulation in the nucleus, enabling selective gene activation. Human genome-wide association studies (GWAS) and gene knockout experiments in mice have elucidated the physiological and pathological roles of IκBζ. Despite the initial focus to its role in activated macrophages, IκBζ has since been recognized as a key player in the IL-17-triggered production of immune molecules in epithelial cells, which has garnered significant clinical interest. Recent research has also unveiled a novel molecular function of IκBζ, linking NF-κB and the POU transcription factors through its N-terminal region, whose role had remained elusive for many years.

Neutrophil extracellular traps trigger alveolar epithelial cell necroptosis through the cGAS-STING pathway during acute lung injury in mice.

Extensive loss of alveolar epithelial cells (AECs) undergoing necroptosis is a crucial mechanism of acute lung injury (ALI), but its triggering mechanism needs to be thoroughly investigated. Neutrophil extracellular traps (NETs) play a significant role in ALI. However, the effect of NETs on AECs' death has not been clarified. Our study found that intratracheal instillation of NETs disrupted lung tissue structure, suggesting that NETs could induce ALI in mice. Moreover, we observed that NETs could trigger necroptosis of AECs in vivo and in vitro. The phosphorylation levels of RIPK3 and MLKL were increased in MLE12 cells after NETs treatment (P < 0.05). Mechanistically, NETs taken up by AECs through endocytosis activated the cGAS-STING pathway and triggered AECs necroptosis. The expression of cGAS, STING, TBK1 and IRF3 were increased in MLE12 cells treated with NETs (P < 0.05). Furthermore, the cGAS inhibitor RU.521 inhibited NETs-triggered AECs necroptosis and alleviated the pulmonary damage induced by NETs in mice. In conclusion, our study demonstrates that NETs taken up by AECs via endocytosis can activate the cGAS-STING pathway and trigger AECs necroptosis to promote ALI in mice. Our findings indicate that targeting the NETs/cGAS-STING/necroptosis pathway in AECs is an effective strategy for treating ALI.

Dietary fiber promotes antigen presentation on intestinal epithelial cells and development of small intestinal CD4+CD8αα+ intraepithelial T cells.

The impact of dietary fiber on intestinal T cell development is poorly understood. Here we show that a low fiber diet reduces MHC-II antigen presentation by small intestinal epithelial cells (IECs) and consequently impairs development of CD4+CD8αα+ intraepithelial lymphocytes (DP IELs) through changes to the microbiota. Dietary fiber supports colonization by Segmented Filamentous Bacteria (SFB), which induces the secretion of IFNγ by type 1 innate lymphoid cells (ILC1s) that lead to MHC-II upregulation on IECs. IEC MHC-II expression caused either by SFB colonization or exogenous IFNγ administration induced differentiation of DP IELs. Finally, we show that a low fiber diet promotes overgrowth of Bifidobacterium pseudolongum, and that oral administration of B. pseudolongum reduces SFB abundance in the small intestine. Collectively we highlight the importance of dietary fiber in maintaining the balance among microbiota members that allow IEC MHC-II antigen presentation and define a mechanism of microbiota-ILC-IEC interactions participating in the development of intestinal intraepithelial T cells.

Hydramethylnon induces mitochondria-mediated apoptosis in BEAS-2B human bronchial epithelial cells.

Typically used household chemicals comprise numerous compounds. Determining mixture toxicity, as observed when using household chemicals containing multiple substances, is of considerable importance from a regulatory perspective. Upon examining the toxic effects of household chemical mixtures, we observed that hydramethylnon combined with tetramethrin resulted in synergistic toxicity. To determine the unknown toxicity mechanism of hydramethylnon, which carries the risk of inhalation exposure when using household chemicals, we conducted a further investigation using BEAS-2B cells, a human bronchial epithelial cell line. Hydramethylnon-induced cytotoxicity was determined following 24 and 48 h of exposure using the water-soluble tetrazolium 1 and lactate dehydrogenase assays. To elucidate the toxicity mechanism, we utilized flow cytometry and measured the levels of apoptosis-related proteins and caspase activities. Given that hydramethylnon, as an insecticide, disrupts the mitochondrial electron transfer chain, we analyzed the relevant mechanisms, including mitochondrial superoxide levels as well as the mitochondrial membrane potential (MMP). Hydramethylnon dose-dependently induced BEAS-2B cell apoptosis via the intrinsic pathway. Furthermore, it significantly increased mitochondrial superoxide levels and disrupted the MMP. Pre-treatment with a caspase inhibitor (Z-DEVD-FMK) confirmed that hydramethylnon induced caspase-dependent apoptosis. Apoptosis, a key event in the toxicological process of chemicals, can lead to lung diseases, including fibrosis and cancer. The results of the present study suggest a mechanism of toxicity of hydramethrylnon, an organofluorine biocide whose toxicity has been little studied, to the lung epithelium. Considering the potential risks associated with inhalation exposure, these results highlight the need for careful management and regulation of hydramethylnon.

Aging alters the expression of trophic factors and tight junction proteins in the mouse choroid plexus.

BACKGROUND: The choroid plexus (CP) is an understudied tissue in the central nervous system and is primarily implicated in cerebrospinal fluid (CSF) production. CP also produces numerous neurotrophic factors (NTF) which circulate to different brain regions. Regulation of NTFs in the CP during natural aging is largely unknown. Here, we investigated the age and gender-specific transcription of NTFs along with the changes in the tight junctional proteins (TJPs) and the water channel protein Aquaporin (AQP1). METHODS: Male and female mice were used for our study. Age-related transcriptional changes were analyzed using quantitative PCR at three different time points: mature adult, middle-aged, and aged. Transcriptional changes during aging were further confirmed with digital droplet PCR. Additionally, we used immunohistochemical analysis (IHC) for the evaluation of in vivo protein expression. We further investigated the cellular phenotype of these NTFS, TJP, and water channel proteins in the mouse CP by co-labeling them with the classical vascular marker, Isolectin B4, and epithelial cell marker, Plectin. RESULTS: Aging significantly altered NTF gene expression in the CP. Brain-derived neurotrophic factor (BDNF), Midkine (MDK), VGF, Insulin-like growth factor (IGF1), IGF2, Klotho (KL), Erythropoietin (EPO), and its receptor (EPOR) were reduced in the aged CP of males and females. Vascular endothelial growth factor (VEGF) transcription was gender-specific; in males, gene expression was unchanged in the aged CP, while females showed an age-dependent reduction. Age-dependent changes in VEGF localization were evident, from vasculature to epithelial cells. IGF2 and klotho localized in the basolateral membrane of the CP and showed an age-dependent reduction in epithelial cells. Water channel protein AQP1 localized in the tip of epithelial cells and showed an age-related reduction in mRNA and protein levels. TJP's JAM, CLAUDIN1, CLAUDIN2 and CLAUDIN5 were reduced in aged mice. CONCLUSIONS: Our study highlights transcriptional level changes in the CP during aging. The age-related transcriptional changes exhibit similarities as well as gene-specific differences in the CP of males and females. Altered transcription of the water channel protein AQP1 and TJPs could be involved in reduced CSF production during aging. Importantly, reduction in the neurotrophic factors and longevity factor Klotho can play a role in regulating brain aging.

Cystathionine Gamma-Lyase Regulates TNF-α-Mediated Injury Response in Human Colonic Epithelial Cells and Colonoids.

Cystathionine gamma-lyase (CSE) and TNF-α are now recognized as key regulators of intestinal homeostasis, inflammation, and wound healing. In colonic epithelial cells, both molecules have been shown to influence a variety of biological processes, but the specific interactions between intracellular signaling pathways regulated by CSE and TNF-α are poorly understood. In the present study, we investigated these interactions in normal colonocytes and an organoid model of the healthy human colon using CSE-specific pharmacological inhibitors and siRNA-mediated transient gene silencing in analytical and functional assays in vitro. We demonstrated that CSE and TNF-α mutually regulated each other's functions in colonic epithelial cells. TNF-α treatment stimulated CSE activity within minutes and upregulated CSE expression after 24 h, increasing endogenous CSE-derived H2S production. In turn, CSE activity promoted TNF-α-induced NF-ĸB and ERK1/2 activation but did not affect the p38 MAPK signaling pathway. Inhibition of CSE activity completely abolished the TNF-α-induced increase in transepithelial permeability and wound healing. Our data suggest that CSE activity may be essential for effective TNF-α-mediated intestinal injury response. Furthermore, CSE regulation of TNF-α-controlled intracellular signaling pathways could provide new therapeutic targets in diseases of the colon associated with impaired epithelial wound healing.

Clarithromycin Modulates Neutrophilic Inflammation Induced by Prevotella intermedia in Human Airway Epithelial Cells.

Objectives: In the present study, we aimed to clarify the mechanisms by which periodontal pathogens, particularly Prevotella intermedia, induce severe neutrophilic inflammation. In addition, we aimed to test the efficacy of macrolides, which has not been resolved in the neutrophilic inflammation induced by P. intermedia. Methods: NCl-H292 human airway epithelial cells were pre-incubated with clarithromycin for 2 h before incubation with P. intermedia supernatants. Then, C-X-C motif chemokine ligand 8 (CXCL8) transcription and interleukin (IL)-8 production were measured. To elucidate the signaling pathway, mitogen-activated protein kinase inhibitors were added to the cell culture, and the cells were subjected to Western blotting. Results:P. intermedia supernatants promoted CXCL8 transcription and IL-8 production, and the reactions were significantly suppressed by clarithromycin pretreatment. Only trametinib, the selective mitogen-activated extracellular signal-regulated kinase inhibitor, downregulated CXCL8 transcription and IL-8 production. Furthermore, Western blotting revealed that stimulation with P. intermedia supernatants specifically induces extracellular signal-regulated kinases (ERK) 1/2 phosphorylation, which is suppressed by clarithromycin pretreatment. Notably, the interference analysis revealed that ERK3 might be dispensable for IL-8 production under the stimulation of P. intermedia supernatants. Conclusions: Our results provide new insight into the mechanism underlying P. intermedia-induced production of IL-8 from human airway epithelial cells. Furthermore, macrolides might have therapeutic potential in regulating periodontal pathogen-induced neutrophilic inflammation in the lungs.