Epithelial Gene Research Articles

Cryptosporidium parvum hijacks a host's long noncoding RNA U90926 to evade intestinal epithelial cell-autonomous antiparasitic defense.

Cryptosporidium is a zoonotic apicomplexan parasite that infects the gastrointestinal epithelium and other mucosal surfaces in humans. It is an important opportunistic pathogen in AIDS patients and a leading cause of infectious diarrhea and diarrheal-related death in children worldwide. The intestinal epithelial cells provide the first line of defense against Cryptosporidium infection and play a central role in activating and regulating the host's antiparasitic response. Increasing evidence suggests that long noncoding RNAs (lncRNAs) participate in host-pathogen interactions and play a regulatory role in the pathogenesis of diseases but the underlying molecular mechanisms are not fully understood. We previously identified a panel of host lncRNAs that are upregulated in murine intestinal epithelial cells following Cryptosporidium infection, including U90926. We demonstrate here that U90926 is acting in a pro-parasitic manner in regulating intestinal epithelial cell-autonomous antiparasitic defense. Inhibition of U90926 resulted in a decreased infection burden of the parasite while overexpression of U90926 showed an increase in infection burden in cultured murine intestinal epithelial cells. Induction of U90926 suppressed transcription of epithelial defense genes involved in controlling Cryptosporidium infection through epigenetic mechanisms. Specifically, transcription of Aebp1, which encodes the Aebp1 protein, a potent modulator of inflammation and NF-κB signaling, was suppressed by U90926. Gain- or loss-of-function of Aebp1 in the host's epithelial cells caused reciprocal alterations in the infection burden of the parasite. Interestingly, Cryptosporidium carries the Cryptosporidium virus 1 (CSpV1), a double-stranded (ds) RNA virus coding two dsRNA fragments, CSpV1-dsRdRp and CSpV1-dsCA. Both CSpV1-dsRdRp and CSpV1-dsCA can be delivered into infected cells as previously reported. We found that cells transfected with in vitro transcribed CSpV1-dsCA or CSpV1-dsRdRp displayed an increased level of U90926, suggesting that CSpV1 is involved in the upregulation of U90926 during Cryptosporidium infection. Our study highlights a new strategy by Cryptosporidium to hijack a host lncRNA to suppress epithelial cell-autonomous antiparasitic defense and allow for a robust infection.

Cis- and trans-eQTM analysis reveals novel epigenetic and transcriptomic immune markers of atopic asthma in airway epithelium

Expression quantitative trait methylation (eQTM) analyses uncover associations between DNA methylation markers and gene expression. Most eQTM analyses of complex diseases have focused on cis-eQTM pairs (within 1 megabase). This study sought to identify cis- and trans-methylation markers associated with gene expression in airway epithelium from youth with and without atopic asthma. In this study, the investigators conducted both cis- and trans-eQTM analyses in nasal (airway) epithelial samples from 158 Puerto Rican youth with atopic asthma and 100 control subjects without atopy or asthma. The investigators then attempted to replicate their findings in nasal epithelial samples from 2 studies of children, while also examining whether their results in nasal epithelium overlap with those from an eQTM analysis in white blood cells from the Puerto Rican subjects. This study identified 9,108 cis-eQTM pairs and 2,131,500 trans-eQTM pairs. Trans-associations were significantly enriched for transcription factor and microRNA target genes. Furthermore, significant cytosine-phosphate-guanine sites (CpGs) were differentially methylated in atopic asthma and significant genes were enriched for genes differentially expressed in atopic asthma. In this study, 50.7% to 62.6% of cis- and trans-eQTM pairs identified in Puerto Rican youth were replicated in 2 smaller cohorts at false discovery rate-adjusted P< .1. Replicated genes in the trans-eQTM analysis included biologically plausible asthma-susceptibility genes (eg, HDC, NLRP3, ITGAE, CDH26, and CST1) and are enriched in immune pathways. Studying both cis- and trans-epigenetic regulation of airway epithelial gene expression can identify potential causal and regulatory pathways or networks for childhood asthma. Trans-eQTM CpGs may regulate gene expression in airway epithelium through effects on transcription factor and microRNA target genes.

WS18.06 The impact of cytomegalovirus on airway epithelial gene expression

Introduction: The pathogenicity of cytomegalovirus (CMV) has predominantly been recognized in immunosuppressed populations & newborns. However, a recent study in persons with CF observed that CMV seropositive individuals died from lung disease 8 years sooner than those who were seronegative. Further, CMV DNA was identified in those individuals’ sputum (Parkins 2019, ERJ). This observation aligns with increasing evidence associating CMV infection with worse outcomes in many inflammatory conditions, and a higher overall mortality. To date, models of CMV infection of human bronchial epithelial (HBE) cells have not been established, limiting our ability to study its impact in CF airways.

Blend of Cinnamaldehyde, Eugenol, and Capsicum Oleoresin Improved Rumen Health of Lambs Fed High-Concentrate Diet as Revealed by Fermentation Characteristics, Epithelial Gene Expression, and Bacterial Community.

We investigated the effects of CEC on the fermentation characteristics, epithelial gene expression, and bacterial community in the rumen of lambs fed a high-concentrate diet. Twenty-four 3-month-old female crossbred lambs with an initial body weight of 30.37 ± 0.57 kg were randomly allocated to consume a diet supplemented with 80 mg/kg CEC (CEC) or not (CON). The experiment consisted of a 14 d adaptation period and a 60 d data collection period. Compared with the CON group, the CEC group had higher ADG, epithelial cell thickness, ruminal butyrate proportion, and lower ammonia nitrogen concentration. Increases in the mRNA expression of Occludin and Claudin-4, as well as decreases in the mRNA expression of apoptotic protease activating factor-1 (Apaf-1), cytochrome c (Cyt-C), Caspase-8, Caspase-9, Caspase-3, Caspase-7, and toll-like receptor 4 (TLR4), were observed in the CEC group. Moreover, CEC treatment also decreased the concentration of IL-1β, IL-12, and TNF-α. Supplementation with CEC altered the structure and composition of the rumen bacterial community, which was indicated by the increased relative abundances of Firmicutes, Synergistota, Rikenellaceae_RC9_gut_group, Olsenella, Schwartzia, Erysipelotrichaceae_UCG-002, Lachnospiraceae_NK3A20_group, Acetitomaculum, [Eubacterium]_ruminantium_group, Prevotellaceae_UCG-004, Christensenellaceae_R-7_group, Sphaerochaeta, Pyramidobacter, and [Eubacterium]_eligens_group, and the decreased relative abundances of Acidobacteriota, Chloroflexi, Gemmatimonadota, and MND1. Furthermore, Spearman correlation analysis revealed that the altered rumen bacteria were closely correlated with rumen health-related indices. Dietary CEC supplementation improved growth performance, reduced inflammation and apoptosis, protected barrier function, and modulated the bacterial community of lambs fed a high-concentrate diet.

The pro- and antineoplastic effects of deoxycholic acid in pancreatic adenocarcinoma cell models

BackgroundCommensal bacteria secrete metabolites that reach distant cancer cells through the circulation and influence cancer behavior. Deoxycholic acid (DCA), a hormone-like metabolite, is a secondary bile acid specifically synthesized by intestinal microbes. DCA may have both pro- and antineoplastic effects in cancers.Methods and resultsThe pancreatic adenocarcinoma cell lines, Capan-2 and BxPC-3, were treated with 0.7 µM DCA, which corresponds to the reference concentration of DCA in human serum. DCA influenced the expression of epithelial to mesenchymal transition (EMT)-related genes, significantly decreased the expression level of the mesenchymal markers, transcription factor 7- like 2 (TCF7L2), snail family transcriptional repressor 2 (SLUG), CLAUDIN-1, and increased the expression of the epithelial genes, zona occludens 1 (ZO-1) and E-CADHERIN, as shown by real-time PCR and Western blotting. Consequently, DCA reduced the invasion capacity of pancreatic adenocarcinoma cells in Boyden chamber experiments. DCA induced the protein expression of oxidative/nitrosative stress markers. Moreover, DCA reduced aldehyde dehydrogenase 1 (ALDH1) activity in an Aldefluor assay and ALDH1 protein level, suggesting that DCA reduced stemness in pancreatic adenocarcinoma. In Seahorse experiments, DCA induced all fractions of mitochondrial respiration and glycolytic flux. The ratio of mitochondrial oxidation and glycolysis did not change after DCA treatment, suggesting that cells became hypermetabolic.ConclusionDCA induced antineoplastic effects in pancreatic adenocarcinoma cells by inhibiting EMT, reducing cancer stemness, and inducing oxidative/nitrosative stress and procarcinogenic effects such as hypermetabolic bioenergetics.

Microbiota-driven changes in colitis susceptibility in CGD mice are associated with alterations in intestinal epithelial reactive oxygen species production and NADPH oxidase subunit gene expression

BackgroundChronic granulomatous disease (CGD) is an inborn error of immunity caused by defects in any one of the 6 subunits (gp91phox, p47phox, p22phox, p67phox, p40phox or chaperone EROS) forming the nicotinamide adenine dinucleotide phosphate oxidase (NADPH) complex 2 (NOX2) resulting in defective phagocyte-derived reactive oxygen species (ROS) production. Almost 50% of patients with CGD suffer from inflammatory bowel disease (IBD). While ROS plays an important role in intestinal homeostasis, the impact of NOX2 defects on intestinal barrier ROS levels is unknown. We previously demonstrated that the intestinal microbiome is a critical driver of colitis susceptibility in mice with CGD. Given the importance of ROS at the intestinal barrier, we hypothesize that the microbiota drives intestinal inflammation by modulating NOX-derived intestinal epithelial ROS production. ObjectiveTo determine whether microbiota-driven changes in colitis susceptibility in mice with CGD are associated with alterations in intestinal epithelial ROS production and NOX gene expression. MethodSusceptibility to dextran sodium sulfate (DSS) colitis was evaluated in CGD mice with distinct microbiota: 1) gp91phox-/- -mice from NIH (non-colitogenic microbiota), 2) gp91phox-/- -mice from IRCM (colitogenic microbiota), 3) p47phox-/- -mice from NIH and IRCM (colitogenic microbiota) and wild type (WT) mice cross-fostered with p47phox-/- -mice (i.e. WT mice colonized with the colitogenic p47phox-/-microbiota). ROS production and NOX (i.e. NOX1, NOX4, NOX2, DUOX2) gene expression was measured in colon epithelial cells isolated from mice used in the aforementioned colitis experiments. ResultsNIH gp91phox-/- -mice did not have increased colitis susceptibility compared to WT mice whereas IRCM gp91phox-/- -mice, p47phox-/- -mice from both facilities and cross-fostered WT mice had increased susceptibility to DSS colitis. Intestinal epithelial cells sorted from mice with increased colitis susceptibility produced more ROS and were associated with distinct patterns of NOX subunit gene expression. ConclusionOur data suggest the microbiota may drive intestinal inflammation in mice with CGD by increasing NOX-derived ROS production in the intestinal epithelium. These findings bring forward a possible mechanism by which the microbiota contributes to the pathogenesis of CGD-associated IBD.

ZFP24 drives SOX9 upregulation and protects tubular epithelial cells during acute kidney injury

SOX9 is a transcription factor that controls cell-fate determination during embryonic development and adult tissue homeostasis in multiple organs including the kidneys. SOX9 expression is low in the adult kidneys, however, stress conditions can trigger its transcriptional upregulation in tubular epithelial cells. Functionally, SOX9 plays a protective role during the early phase of acute kidney injury (AKI) and facilitates repair during the recovery phase. To identify the upstream transcriptional regulators that drive SOX9 upregulation in tubular epithelial cells, here we have used an unbiased transcription factor screening approach. Our preliminary screening and validation studies show that Zinc finger protein 24 (ZFP24) controls injury induced SOX9 upregulation in tubular epithelial cells. ZFP24, a Cys2-His2 (C2H2) zinc finger protein is essential for oligodendrocyte maturation and myelination, however its role in the kidneys or in SOX9 regulation remains unknown. We find that tubular epithelial ZFP24 gene ablation exacerbates ischemia, rhabdomyolysis, and cisplatin-associated AKI. Importantly, ZFP24 gene deletion results in suppression of SOX9 upregulation in injured tubular epithelial cells. Chromatin immunoprecipitation and promoter luciferase assays confirmed that ZFP24 binds to a specific site in both murine and human SOX9 promoter. Importantly, CRISPR/Cas9 mediated introduction of mutations in the ZFP24 binding site in the SOX9 promoter in vivo led to suppression of SOX9 upregulation during AKI. These findings identify ZFP24 as a critical stress-responsive transcription factor that protects tubular epithelial cells during AKI in part through SOX9 upregulation. The current study was supported by NIDDK 1R01DK132230 grant to N.P. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transcription factor HNF4A activity is suppressed by microbiota and inhibits IFN beta production

Intestinal epithelial cells (IECs) separate the intestinal lumen from lamina propria resident immune cells, positioning IECs as mediators of microbial signals to the immune system. Understanding these microbe-IEC-immune interactions may represent potential therapeutic targets for immunological diseases. We previously discovered that microbiota regulate the activity of the nuclear receptor transcription factor Hepatocyte nuclear factor 4 alpha (HNF4A). Microbiota suppress HNF4A-activated genes in zebrafish and lead to genome-wide reduction of HNF4A DNA occupancy in mouse IECs. HNF4A activates lipid metabolism and epithelial differentiation gene programs, while also suppressing inflammatory and immune response gene programs in the intestine. We therefore hypothesized that microbial suppression of HNF4A contributes to activation of immunological pathways. We conducted an unbiased coimmunoprecipitation-mass-spectrometry analysis comparing HNF4A interacting partners in IECs from germ-free and conventionalized (germ-free mice colonized with SPF feces for 2 weeks) mice. HNF4A interacted with significantly more proteins in germ-free IECs, including several proteins involved in promotion of transcription and chromatin regulation, consistent with HNF4A being more active in germ-free mice. Our HNF4A and H3k27ac ChIP-seq data from IECs derived from germ-free and conventionalized mice identified that HNF4A binds ubiquitously to IEC enhancers, but also revealed a small number of enhancers that were activated by microbiota with no HNF4A binding. Motif enrichment analysis showed that these enhancers were enriched for binding sites for Interferon regulatory factors (IRFs). This raises the interesting possibility that there is a selective disadvantage to colocalizing IRF and HNF4A occupancy at a given enhancer, and suggests that these transcriptional regulatory pathways may otherwise communicate. To test this, we used a luciferase reporter assay in HEK293T cells to probe the impact of HNF4A on the IFNβ promoter, which is controlled by IRF3/7. HNF4A potently suppressed IFNβ promoter activity following viral stimulation. HNF4A DNA-binding activity is necessary for this suppression; however, there is no evidence HNF4A binds the IFNβ promoter, suggesting HNF4A likely induces a repressor of the IFNβ promoter. Together these results indicate that HNF4A is both a target of microbiota suppression and a potent suppressor of IFNβ production. Though IRF bound enhancers appear to be insulated against HNF4A binding in IECs, our results show that these two transcriptional pathways communicate, potentially representing a novel mechanism through which microbiota influence innate immunity. NIH P01-DK094779 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Transcriptional repression of the MRTF/SRF-cytoskeleton pathway by Rev-erba promotes beigeing via adipogenic progenitor fate switch

The circadian clock exerts temporal control in metabolic processes to maintain homeostasis, with its disruption leading to the development of obesity and insulin resistance. Adipose fibrosis in obese subjects exacerbates insulin resistance by restricting healthy tissue expansion and remodeling. Rev-erbα is a key circadian clock repressor that displays circadian rhythmic expression in adipose tissue, although its role in adipose tissue fibrosis is not known. Here we show that Rev-ebα inhibits the fibrogenic fate of adipocyte progenitors while promoting beige adipogenic potential via transcription repression of the MRTF/SRF-actin cytoskeleton axis. ChIP-seq analysis of Rev-erbα cistrome in adipogenic precursors identified its transcriptional control of pathways involved in cytoskeleton modulation, including established myofibroblast gene markers small muscle α-actin and Tropomysin. Gain-of-function of Rev-erbα in beige adipogenic precursors markedly suppressed MRTF/SRF activity with enhanced beige differentiation, while Rev-erbα silencing suppressed beige adipogenesis. Prrx1-Cre-mediated subcutaneous beige fat-selective Rev-erbα knock-in induced browning with augmented mitochondrial metabolism, resulting in increased energy expenditure, resistance to obesity and insulin sensitivity. Furthermore, single cell RNA-seq of beige progenitors with Rev-erbα overexpression revealed striking loss of preadipcyte-like (PAL) subpopulations with myofibroblastic characteristics that arise from pericyte lineage. PAL beige progenitors displayed enrichment of epithelial mesenchymal transition-related gene signature and contractile program as compared to preadipocytes. Preadipocyte population with Rev-erbα overexpression exhibited activated oxidative phosphorylation pathway with inhibition of myofibrolast characteristics. Taken together, our findings identify a novel regulatory function of Rev-erbα in modulating adipogenic progenitor fate choice that may promote adipose tissue beigeing while suppressing fibrotic complications. NIDDK grant 1R01DK112794, 1R01DK130499 and AR-DMRI 2023 T2D Innovation Grant This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

RNA sequencing and expression analysis reveal a role for Lhx9 in the haploinsufficient adult mouse ovary

Understanding the molecular pathways that underpin ovarian development and function is vital for improving the research approaches to investigating fertility. Despite a significant improvement in our knowledge of molecular activity in the ovary, many questions remain unanswered in the quest to understand factors influencing fertility and ovarian pathologies such as cancer. Here, we present an investigation into the expression and function of the developmental transcription factor LIM Homeobox 9 (LHX9) in the adult mouse ovary. We have characterized Lhx9 expression in several cell types of the mature ovary across follicle stages. To evaluate possible LHX9 function in the adult ovary, we investigated ovarian anatomy and transcription in an Lhx9+/- knockout mouse model displaying subfertility. Despite a lack of gross anatomical differences between genotypes, RNA-sequencing found that 90 differentially expressed genes between Lhx9+/ - and Lhx9+/+ mice. Gene ontology analyses revealed a reduced expression of genes with major roles in ovarian steroidogenesis and an increased expression of genes associated with ovarian cancer. Analysis of the ovarian epithelium revealed Lhx9+/ - mice have a disorganized epithelial phenotype, corresponding to a significant increase in epithelial marker gene expression. These results provide an analysis of Lhx9 in the adult mouse ovary, suggesting a role in fertility and ovarian epithelial cancer.

Abstract 3604: Epithelial Caveolin-1 regulates lung metastasis in advanced stages of breast cancer

Abstract Organotypic metastasis is a well-orchestrated sequence of events that takes place in tumors. The interplay between secretory factors from the primary tumor and the microenvironment of a distant organ determines the fate of metastasis. A significant concern in effective triple-negative breast cancer (TNBC) treatment is lung metastasis. Caveolin-1 (Cav-1), a lipid raft protein, is an important component of the metastatic interplay and is reported to be upregulated in the advanced metastatic stage of breast cancer. Although Cav-1 has been shown to have oncogenic potential, its role in TNBC lung metastasis is not fully understood. Our data illustrates, knocking out Cav-1 in the 4T1 cells (a mouse breast cancer cell line) affects cell morphology, extracellular vesicle formation, and MMP release in vitro. Furthermore, a wound healing/cell migration assay showed reduced migration in Cav-1 KO 4T1 cells when compared to control 4T1 cells, and these findings were validated using Cav-1 siRNA. For investigating the metastatic role, we injected Cav-1 KO 4T1 and control 4T1 cells into the mammary fat pad of female BALB/c mice, a syngeneic mouse model of triple-negative breast cancer. We found no evidence of lung metastasis in Cav-1 KO 4T1 injected mice when compared to control 4T1 injected mice. This was further supported by mRNA profiling of the tumor. We observed 21 epithelial cell migration genes that are differentially expressed in Cav-1 KO tumors when compared to WT tumors. Correlation analysis from Breast Cancer Gene-Expression Miner v4.8 (bc-GenExMiner), a human database, showed a significant correlation between Cav-1 expression and several of the 21 epithelial cell migration genes, along with integrin 3 alpha (ITGα3). Interestingly, in silico protein docking predicted an interaction between Cav-1 and ITGα3, which was later confirmed by co-immunoprecipitation. The role of ITGα3 in metastasis was further corroborated by cell migration assay, which was affected when siRNA was used to silence ITGα3 gene expression. Collectively, these findings provide evidence that Cav-1 KO, along with ITGa3, plays an important role in distant lung metastasis in the 4T1 tumor-induced mice model. Citation Format: Dhirendra Pratap Singh, Rashmi Pathak, Abhishek Pandit, Philip J. Ebenezer, Nithya Jambunathan, Sanjay Kumar, Alexander Du Plooy, Joseph Francis, Mary E. White. Epithelial Caveolin-1 regulates lung metastasis in advanced stages of breast cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3604.

Abstract 2454: Identification of colorectal cancer stem cells from single cell RNA sequencing

Abstract Cancer stem cells (CSCs) play a critical role in metastasis, relapse and therapy resistance in colorectal cancer (CRC). Although the normal lineage of cell development in the intestine has identified many of the genes involved in the induction and maintenance of pluripotency, recent studies of CSCs suggest significant heterogeneity and lack of common surface markers for identification. In this study, we perform single cell RNA sequencing (scRNA-seq) to extract a single cell stemness signature (SCS_sig) for colorectal CSCs identification and as a potential predictor of relapse after surgical resection. A total of 26 fresh surgery specimens (6 colon tumor, 3 colon matched normal, 9 liver metastasis, 8 liver matched normal) from neoadjuvant chemotherapy (NAC) treated patients with single-cell transcriptome generated using 10X Chromium scRNA-seq and Illumina platforms were analyzed. Following extensive quality control and batch effect correction, we identified 20k epithelial cells using canonical epithelial cell marker genes (EPCAM, KRT8 and KRT18) from a total of 111,200 cells, with mean 1113 epithelial cell per sample (excluding liver normal samples).To obtain the CSCs profiling signature, we first annotated a ‘gold-standard’ set of CSC that expressed all canonical colon CSC marker genes (LGR5, ASCL2, EPHB2, PROM1, AXIN2, LEFTY1, RNF43, CD44 and SLC12A2), identifying 346 CSCs (1.71% of epithelial cells). Published stemness signatures were significantly enriched in the gold standard stem cells (false discovery rate (FDR) &amp;lt; 0.05). Then we selected the 50 most significantly up-regulated genes in this gold standard set (relative to other epithelial cells) as a single-cell stemness signature (named SCS_sig hereafter). Interesting, we saw that in every tumor there was a continuum of stemness, rather than distinct stem and differentiated populations. The stemness state by SCS_sig was positively correlated with less differentiated state calculated by CytoTRACE score (r = 0.76, p&amp;lt; 0.001), a computational method that predicts the differentiation state of cells from scRNA-seq data. The SCS_sig was significantly higher in tumor cells compared to normal cells in our cohort as well as the previously published SMC cohort (fold change = 2.52 and p &amp;lt; 0.001, fold change = 1.44 and p &amp;lt; 0.001, respectively). There was notable heterogeneity in the fraction of stem-like tumor cells with in 15 tumor samples, with the tumor with greatest CSC percentage having the shortest time to relapse. The SCS_sig generated from stem-like cells can identify the stemness state of epithelial cells in scRNAseq data. A signature score is more simple and robust than using few or panel of CSCs marker genes to identify single CSC because of the reads dropout in scRNA-seq. Further investigation of the SCS_sig as a predictive and prognostic biomarker in CRC is ongoing in larger patient cohorts. Citation Format: Kangyu Lin, Mohammad Zeineddine, Saikat Chowdhury, Nicholas Hornstein, Sendurai Mani, Scott Kopetz, John Paul Shen. Identification of colorectal cancer stem cells from single cell RNA sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2454.

Effects of supplemental fulvic acid on survival, growth performance, digestive ability and immunity of large yellow croaker (Larimichthys crocea) larvae.

A 30-day feeding trial was designed to evaluate the effect of supplemental fulvic acid (FA) on survival, growth performance, digestive ability and immunity of large yellow croaker (Larimichthys crocea) larvae (initial body weight 11.33 ± 0.57mg). Four isonitrogenous and isolipids diets containing 0.00%, 0.01%, 0.02% and 0.04% FA were formulated, respectively. Results showed that the supplementation of 0.04% FA significantly improved survival rate of large yellow croaker larvae. Meanwhile, supplemental FA significantly increased final body weight and specific growth rate. Based on the specific growth rate, the optimal supplementation was 0.0135% FA. Larvae fed the diet with 0.01% FA had significantly higher villus height than the control. The supplementation of 0.01%-0.02% FA significantly increased the muscular thickness of intestine. Moreover, supplementation of FA significantly increased mRNA expression of intestinal epithelial proliferation and barrier genes (pcna, zo-1 and zo-2). Diets supplemented with 0.02%-0.04% FA significantly increased the activity of trypsin in the intestinal segment, while 0.01%-0.02% FA significantly increased the activity of trypsin in the pancreatic segment. Compared with the control, supplementation of FA remarkably increased activities of alkaline phosphatase and leucine aminopeptidase in the brush border membrane of intestine. Larvae fed the diet with 0.01% FA significantly increased activities of lysozyme and total nitric oxide synthase. Furthermore, the supplementation of 0.01% to 0.02% FA significantly decreased the mRNA expression of pro-inflammatory cytokines (tnf-α and il-6). Concurrently, supplemental FA significantly increased anti-inflammatory cytokine (il-10) mRNA expression level. In conclusion, this study indicated that the supplementation of FA could improve the survival rate and growth performance of larvae by promoting intestinal development, digestive enzymes activities and innate immunity.

Cholesterol depletion affects caveolin-1 expression, migration and invasion of oral tongue squamous cell carcinoma cell lines

IntroductionCholesterol is a key lipid molecule within cell membranes. This is especially true in cavelolas, invaginated membrane nanodomains, which present the protein caveolin-1 (CAV-1). It is important to note that this structure is involved in many cell signalling pathways. Additionally, high cholesterol is seen in different tumor types but little is known in regards to oral tongue squamous cell carcinoma (OTSCC). The aim of this study was to evaluate the influence of cholesterol depletion on primary (SCC-25) and metastatic (HSC-3) OTSCC cell lines. Materials and methodsCell membrane fluidity, cell viability, gene and protein expression of CAV-1 and of epithelial-mesenchymal transition (EMT) markers, cell migration in Myogel and invasion-myoma assay were evaluated after cholesterol depletion with methyl-β-cyclodextrin (MβCD - 7.5, 10 or 15 mM) ResultsDecreased cell viability and increased membrane fluidity of SCC-25 cells was seen with cholesterol depletion but cell viability was less affected and there was no effect on membrane fluidity in HSC-3. Cholesterol depletion also decreased CAV-1 at 6 h but increased it after 24 h.; both epithelial and mesenchymal EMT genes were upregulated after 6 h, followed by downregulation at 24 h in SCC-25. In HSC-3, CAV-1 was downregulated, and E-cadherin gene (ECAD) was upregulated at 6 h. Only the protein β-catenin in SCC-25 was affected, and cell migration of both cell lines was decreased, affecting SCC-25 more intensely. The invasive capacity within human myoma organotypic model was increased in SCC-25 and decreased in HSC-3. ConclusionCholesterol depletion affects CAV-1 and ECAD inversely. This affect also depends on cell type since the invasive capacity was augmented in primary cells while decreased in metastatic cells.

Zinc finger protein 24-dependent transcription factor SOX9 up-regulation protects tubular epithelial cells during acute kidney injury

Transcriptional profiling studies have identified several protective genes upregulated in tubular epithelial cells during acute kidney injury (AKI). Identifying upstream transcriptional regulators could lead to the development of therapeutic strategies augmenting the repair processes. SOX9 is a transcription factor controlling cell-fate during embryonic development and adult tissue homeostasis in multiple organs including the kidneys. SOX9 expression is low in adult kidneys; however, stress conditions can trigger its transcriptional upregulation in tubular epithelial cells. SOX9 plays a protective role during the early phase of AKI and facilitates repair during the recovery phase. To identify the upstream transcriptional regulators that drive SOX9 upregulation in tubular epithelial cells, we used an unbiased transcription factor screening approach. Preliminary screening and validation studies show that zinc finger protein 24 (ZFP24) governs SOX9 upregulation in tubular epithelial cells. ZFP24, a Cys2-His2 (C2H2) zinc finger protein, is essential for oligodendrocyte maturation and myelination; however, its role in the kidneys or in SOX9 regulation remains unknown. Here, we found that tubular epithelial ZFP24 gene ablation exacerbated ischemia, rhabdomyolysis, and cisplatin-associated AKI. Importantly, ZFP24 gene deletion resulted in suppression of SOX9 upregulation in injured tubular epithelial cells. Chromatin immunoprecipitation and promoter luciferase assays confirmed that ZFP24 bound to a specific site in both murine and human SOX9 promoters. Importantly, CRISPR/Cas9-mediated mutation in the ZFP24 binding site in the SOX9 promoter invivo led to suppression of SOX9 upregulation during AKI. Thus, our findings identify ZFP24 as a critical stress-responsive transcription factor protecting tubular epithelial cells through SOX9 upregulation.

The epithelial polarity genes frazzled and GUK-holder adjust morphogen gradients to coordinate changes in cell position with cell fate specification

Morphogenetic gradients specify distinct cell populations within tissues. Originally, morphogens were conceived as substances that act on a static field of cells, yet cells usually move during development. Thus, the way cell fates are defined in moving cells remains a significant and largely unsolved problem. Here, we investigated this issue using spatial referencing of cells and 3D spatial statistics in the Drosophila blastoderm to reveal how cell density responds to morphogenetic activity. We show that the morphogen decapentaplegic (DPP) attracts cells towards its peak levels in the dorsal midline, whereas dorsal (DL) stalls them ventrally. We identified frazzled and GUK-holder as the downstream effectors regulated by these morphogens that constrict cells and provide the mechanical force necessary to draw cells dorsally. Surprisingly, GUKH and FRA modulate the DL and DPP gradient levels and this regulation creates a very precise mechanism of coordinating cell movement and fate specification.

A dual role of microbiota type 17 immunity in tissue repair and pain.

In this commentary, we discuss the findings of Enamorado etal. who have, for the first time, demonstrated that immunity to the microbiota enhances repair of cutaneous sensory nerves and epithelial tissues following skin injury. Commensal-specific IL-17 producing CD4+ T helper cells have direct contact with injured sensory neurons, inducing multiple epithelial and neuronal repair genes. We speculate that an altered balance of T cell populations in the skin of people with chronic neuropathic pain may contribute to a reduction in neuronal repair and the consequent decease in intraepidermal nerve fibre density and persistent pain.

The role of FIBCD1 in response to Aspergillus fumigatus in lung epithelial cells.

Chitin, a polysaccharide, is ubiquitously found in nature and has been known to be an active immunogen in mammals, and interacts with Toll-like, mannose and glucan receptors, to induce cytokine and chemokine secretions. FIBCD1 is a tetrameric type II transmembrane endocytic vertebrate receptor that binds chitin, is found in human lung epithelium and modulates lung epithelial inflammatory responses to A. fumigatus cell wall polysaccharides. We previously reported the detrimental role of FIBCD1 in a murine model of pulmonary invasive aspergillosis. However, the effect that chitin and chitin-containing A. fumigatus conidia exerts on lung epithelium following exposure through FIBCD1 is not yet fully explored. Using both in vitro and in vivo strategies, we examined how lung and lung epithelial gene expression are modified after exposure to fungal conidia or chitin fragments in the presence or absence of FIBCD1. FIBCD1 expression was associated with a decrease in inflammatory cytokines with increasing size of chitin (dimer-oligomer). Thus, our results demonstrate that FIBCD1 expression modulates cytokine and chemokine expression in response to A. fumigatus conidia that is modified by the presence of chitin particles.

Phosphorylation of PHF2 by AMPK releases the repressive H3K9me2 and inhibits cancer metastasis

Epithelial to mesenchymal transition (EMT) plays a crucial role in cancer metastasis, accompanied with vast epigenetic changes. AMP-activated protein kinase (AMPK), a cellular energy sensor, plays regulatory roles in multiple biological processes. Although a few studies have shed light on AMPK regulating cancer metastasis, the inside epigenetic mechanisms remain unknown. Herein we show that AMPK activation by metformin relieves the repressive H3K9me2-mediated silencing of epithelial genes (e.g., CDH1) during EMT processes and inhibits lung cancer metastasis. PHF2, a H3K9me2 demethylase, was identified to interact with AMPKα2. Genetic deletion of PHF2 aggravates lung cancer metastasis and abolishes the H3K9me2 downregulation and anti-metastasis effect of metformin. Mechanistically, AMPK phosphorylates PHF2 at S655 site, enhancing PHF2 demethylation activity and triggering the transcription of CDH1. Furthermore, the PHF2-S655E mutant that mimics AMPK-mediated phosphorylation status further reduces H3K9me2 and suppresses lung cancer metastasis, while PHF2-S655A mutant presents opposite phenotype and reverses the anti-metastasis effect of metformin. PHF2-S655 phosphorylation strikingly reduces in lung cancer patients and the higher phosphorylation level predicts better survival. Altogether, we reveal the mechanism of AMPK inhibiting lung cancer metastasis via PHF2 mediated H3K9me2 demethylation, thereby promoting the clinical application of metformin and highlighting PHF2 as the potential epigenetic target in cancer metastasis.

Assessing the epithelial-to-mesenchymal plasticity in a small cell lung carcinoma (SCLC) and lung fibroblasts co-culture model.

The tumor microenvironment (TME) is the source of important cues that govern epithelial-to-mesenchymal transition (EMT) and facilitate the acquisition of aggressive traits by cancer cells. It is now recognized that EMT is not a binary program, and cancer cells rarely switch to a fully mesenchymal phenotype. Rather, cancer cells exist in multiple hybrid epithelial/mesenchymal (E/M) states responsible for cell population heterogeneity, which is advantageous for the ever-changing environment during tumor development and metastasis. How are these intermediate states generated and maintained is not fully understood. Here, we show that direct interaction between small cell lung carcinoma cells and lung fibroblasts induces a hybrid EMT phenotype in cancer cells in which several mesenchymal genes involved in receptor interaction with the extracellular matrix (ECM) and ECM remodeling are upregulated while epithelial genes such as E-cadherin remain unchanged or slightly increase. We also demonstrate that several core EMT-regulating transcription factors (EMT-TFs) are upregulated in cancer cells during direct contact with fibroblasts, as is Yes-associated protein (YAP1), a major regulator of the Hippo pathway. Further, we show that these changes are transient and reverse to the initial state once the interaction is disrupted. Altogether, our results provide evidence that tumor cells' direct contact with the fibroblasts in the TME initiates a signaling cascade responsible for hybrid E/M states of cancer cells. These hybrid states are maintained during the interaction and possibly contribute to therapy resistance and immune evasion, while interference with direct contact will result in slow recovery and switch to the initial states.