Significant Reduction In Expression Research Articles

TMET-06. CLIP3 DOWNREGULATION LEADS TO RADIORESISTANCE IN GLIOBLASTOMA BY PROMOTING GLYCOLYTIC FLUX

Abstract Glioblastoma Multiforme (GBM), a highly aggressive primary brain tumor, often develops resistance to standard treatments such as ionizing radiation (IR), which leads to a median survival of about 15 months. GBM contains glioblastoma stem cells (GSCs), which are crucial in driving therapeutic resistance and recurrence. In our study, we conducted comprehensive analyses to evaluate the molecular changes associated with radioresistance and explored the role of the Spy1-CLIP3 axis as a key regulator of GSC maintenance. Our methods included quantitative PCR and immunoblotting to measure CLIP3 mRNA and protein levels, revealing a significant reduction in expression among radioresistant GBM cells. We found that exposure to IR leads to the upregulation of Spy1 and downregulation of CLIP3, contributing to the development of radioresistance in surviving GBM cells. We used metabolic flux analysis techniques to observe changes in glycolytic activity, which increased in correlation with CLIP3 downregulation. IR induces CLIP3 downregulation, increasing glycolytic activity by facilitating the trafficking of GLUT3, the primary glucose transporter in GSCs. Additionally, colony-forming ability was evaluated using colony-forming assay after treatment of glimepiride with or without IR. Glimepiride didn’t reduce colony-forming ability in non-irradiated cells, but when combined with IR, it significantly reduced colony-forming ability, possibly by disrupting maintenance of GSCs. Importantly, our data reveal that glimepiride, a CLIP3 activator targets GSCs metabolism and enhances radiosensitization while maintaining low toxicity. The radioresistant GBM cells that survive radiotherapy exhibit increased stemness and glycolytic activity mediated by the Spy1-CLIP3 axis. Overall, our findings suggest that clinical trials using glimepiride for GBM patients may potentially improve survival rates, particularly for those experiencing recurrence after radiotherapy. This research highlights the importance of targeting cellular metabolism and stem cell properties in the context of GBM radioresistance and suggests potential avenues for improving the effectiveness of existing treatments.

Doxorubicin treatment reduces expression of cardiac iron transporters

Doxorubicin (DOX) is an effective anticancer therapy. Unfortunately, the toxicity of DOX is not limited to cancerous cells, with the heart particularly prone to DOX-induced damage. While the mechanisms of DOX cardiotoxicity remain unclear, accumulation of iron within the heart may exacerbate the detrimental effects of DOX. Thus, understanding the effects of DOX on iron transport and storage protein expression would provide further insight on the mechanisms of disrupted iron handling and may lead to potential therapeutic targets for cardioprotection. Our goal was to investigate changes in gene expression of iron transporters in a preclinical model of DOX-induced cardiotoxicity. Female Sprague Dawley rats (2-3 month-old) were randomly divided to receive DOX or saline consistent with standard clinical treatment (i.e., intravenous infusion once every 3 weeks for 4 total cycles and a cumulative dose of ~160 mg/m2). One week following the fourth cycle measures of cardiac function, assessed by echocardiography, and cardiorespiratory capacity, determined by a graded exercise tolerance test, were completed. Cardiac tissue was also collected and cardiac mitochondria were isolated for measurement of reactive oxygen species production. At endpoint, DOX treatment resulted in a lower heart weight to tibia length ratio, reduced cardiorespiratory capacity, impaired ventricular fractional shortening and greater cardiac mitochondrial hydrogen peroxide emission. We found significant reductions in expression of transmembrane/cytoplasmic iron transporters (transferrin receptor 1 and divalent metal transporter 1) and the inner mitochondrial membrane transporter mitoferrin-2 with DOX treatment compared to saline. Expression of genes encoding for ferroportin-1, mitoferrin-1, ABCB8 and ferrochelatase were also downregulated in the DOX-treated group compared to saline, but these did not reach statistical significance. These findings are the first to describe changes in gene expression of proteins involved in iron homeostasis in a clinically relevant model of DOX-induced cardiotoxicity. Further studies are needed to investigate interventional approaches that improve cardiac iron handling to determine if they provide cardioprotection during DOX treatment. This research was funded by the National Institute of Health (NIH), R01 HL144858. This is the full abstract presented at the American Physiology Summit 2024 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.

THE EFFECT OF TREATMENT ON THE INFLAMMATION PROFILE AMONG PATIENTS WITH PRIMARY ALDOSTERONISM

Objective: Due to direct and indirect effects of aldosterone various pathways of inflammation cascade are activated leading to further end organ damage and higher cardiovascular risk among patients with primary aldosteronism (PA). To what extent the pro-inflammatory effects occur and, more importantly, if they are affected by the PA treatment remain unclear. Therefore, we aimed to analyze the inflammation profile among patients with PA before and after the treatment. Design and method: 46 patients with PA (43% with adrenal adenoma and 57% with bilateral hyperplasia) were included into this study. Patient serum samples were collected at the study entry and 6 months after the treatment of PA was initiated. Demographic, clinical and laboratory data were collected retrospectively. Inflammatory cytokines and proteins were measured in patient’s serum using proximity extension assay (O-link Inflammation panel, Olink Proteomics, Uppsala, Sweden). Results: There were 52% woman and 48% men with a mean age of 50.2±12 years. The median aldosterone-renin-quotient (ARQ) was 96 and the blood pressure values were ranging between 142±17/89±12 mmHg. 6 months following the treatment a significant reduction in blood pressure and ARQ was achieved. Analysis of association between clinical factors and biomarker expression has shown that patients with adrenal adenoma have significantly higher levels of FGF21, whereas female gender was associated with lower expression of pro-inflammatory cytokines such as IL-18, TNFRSF9, CXCL9 and higher expression of protective cytokines such as TWEAK and MCP-4, especially among females with bilateral hyperplasia. According to proteomic analysis at study entry, we have identified 4 patient clusters. Interestingly, young females with adrenal adenoma have composed a separate cluster with significantly higher levels of IL-6, IFN-gamma, MCP-1, MMP1 and FGF21 and robust reduction of these parameters following the treatment. In general, volcano plot analysis of whole study cohort has demonstrated the significant reduction in expression of pro-inflammatory cytokines (EN-RAGE, CCL23, OPG, IL-10, FGF21 etc). Conclusions: The treatment of primary aldosteronism leads to reduced expression of pro-inflammatory proteins. The extent of inflammatory activation as well as response to treatment is highly associated with gender and the cause of aldosterone excess.

A conserved NR5A1-responsive enhancer regulates SRY in testis-determination

The Y-linked SRY gene initiates mammalian testis-determination. However, how the expression of SRY is regulated remains elusive. Here, we demonstrate that a conserved steroidogenic factor-1 (SF-1)/NR5A1 binding enhancer is required for appropriate SRY expression to initiate testis-determination in humans. Comparative sequence analysis of SRY 5’ regions in mammals identified an evolutionary conserved SF-1/NR5A1-binding motif within a 250 bp region of open chromatin located 5 kilobases upstream of the SRY transcription start site. Genomic analysis of 46,XY individuals with disrupted testis-determination, including a large multigenerational family, identified unique single-base substitutions of highly conserved residues within the SF-1/NR5A1-binding element. In silico modelling and in vitro assays demonstrate the enhancer properties of the NR5A1 motif. Deletion of this hemizygous element by genome-editing, in a novel in vitro cellular model recapitulating human Sertoli cell formation, resulted in a significant reduction in expression of SRY. Therefore, human NR5A1 acts as a regulatory switch between testis and ovary development by upregulating SRY expression, a role that may predate the eutherian radiation. We show that disruption of an enhancer can phenocopy variants in the coding regions of SRY that cause human testis dysgenesis. Since disease causing variants in enhancers are currently rare, the regulation of gene expression in testis-determination offers a paradigm to define enhancer activity in a key developmental process.

Hsa‑miR‑455‑3P as a predictive biomarker of anemia in patients with non‑small cell lung cancer treated with carboplatin plus paclitaxel.

Lung cancer is the leading cause of cancer-related morbidity and mortality worldwide. The initial treatment of lung cancer depends on the definition of the tumor type and its staging. The most common treatment is chemotherapy, and the first-line treatment is a combination of carboplatin and paclitaxel. Although this treatment has good efficacy, there is a high prevalence of adverse events, particularly hematological reactions. Studies on new biomarkers related to these adverse events, such as circulating microRNAs (miRNAs/miRs), are important for optimizing the quality of life of patients. miRNAs have high stability in several biological fluids and they have specific expressions in different tissues or pathologies. Thus, the present study aimed to assess the relationship between circulating miRNAs and adverse hematologic reactions caused by treatment with carboplatin + paclitaxel in patients with lung cancer. Blood was collected from patients before and 15 days after chemotherapy for hematological adverse reaction analysis, microarray and quantitative (q)PCR validation. Adverse reactions were classified according to the Common Terminology Criteria for Adverse Events v4.0. Microarray analysis was performed using plasma from six patients without anemia and six patients with anemia, and nine miRNAs were differentially expressed. miR-1273g-3p, miR-3613-5p and miR-455-3p, identified using microarray, were assessed using qPCR in 20 patients without anemia and 26 patients with anemia. Bioinformatic analyses of miR-455-3p were performed using miRWalk, the Database for Annotation, Visualization and Integrated Discovery and GeneMania software. Microarray analysis of patients with and without anemia revealed nine significant differentially-expressed plasma miRNAs among these patients. Of these, miR-1273g-3p, miR-3613-5p and miR-455-3p were chosen for further assessment. Only miR-455-3p demonstrated a significant reduction in expression (P=0.04) between the groups before chemotherapy with carboplatin + paclitaxel. Bioinformatics analysis of miR-455-3p revealed a relationship between this miRNA and the hematopoietic pathway, particularly with respect to the RUNX family transcription factor 1 (RUNX1) and TAL bHLH transcription factor 1, erythroid differentiation factor (TAL1) genes. The most prevalent adverse reactions in patients with lung cancer treated with carboplatin + paclitaxel were hematological, particularly anemia. This adverse reaction, caused by dysfunction of the hematopoietic system, may be explained by a possible association between the important genes in this system, RUNX1 and TAL1, and hsa-miR-455-3p.

Impact of umbelliprenin-containing niosome nanoparticles on VEGF-A and CTGF genes expression in retinal pigment epithelium cells.

To investigate the impact of niosome nanoparticles carrying umbelliprenin (UMB), an anti-angiogenic and anti-inflammatory plant compound, on the expression of vascular endothelial growth factor (VEGF-A) and connective tissue growth factor (CTGF) genes in a human retinal pigment epithelium (RPE)-like retina-derived cell line. UMB-containing niosomes were created, optimized, and characterized. RPE-like cells were treated with free UMB and UMB-containing niosomes. The IC50 values of the treatments were determined using an MTT assay. Gene expression of VEGF-A and CTGF was evaluated using real-time polymerase chain reaction after RNA extraction and cDNA synthesis. Niosomes' characteristics, including drug entrapment efficiency, size, dispersion index, and zeta potential were assessed. Free UMB had an IC50 of 96.2 µg/mL, while UMB-containing niosomes had an IC50 of 25 µg/mL. Treatment with UMB-containing niosomes and free UMB resulted in a significant reduction in VEGF-A expression compared to control cells (P=0.001). Additionally, UMB-containing niosomes demonstrated a significant reduction in CTGF expression compared to control cells (P=0.05). However, there was no significant reduction in the expression of both genes in cells treated with free UMB. Both free UMB and niosome-encapsulated UMB inhibits VEGF-A and CTGF genes expression. However, the latter demonstrates significantly greater efficacy, potentially due to the lower UMB dosage and gradual delivery. These findings have implications for anti-angiogenesis therapeutic approaches targeting age-related macular degeneration.

Myricetin induces M2 macrophage polarization to alleviate renal tubulointerstitial fibrosis in diabetic nephropathy via PI3K/Akt pathway.

Development of end-stage renal disease is predominantly attributed to diabetic nephropathy (DN). Previous studies have indicated that myricetin possesses the potential to mitigate the pathological alterations observed in renal tissue. Nevertheless, the precise molecular mechanism through which myricetin influences the progression of DN remains uncertain. To investigate the effects of myricetin on DN and explore its potential therapeutic mechanism. Db/db mice were administered myricetin intragastrically on a daily basis at doses of 50 mg/kg or 100 mg/kg for a duration of 12 wk. Subsequently, blood and urine indexes were assessed, along with examination of renal tissue pathology. Kidney morphology and fibrosis were evaluated using various staining techniques including hematoxylin and eosin, periodic acid-Schiff, Masson's trichrome, and Sirius-red. Additionally, high-glucose culturing was conducted on the RAW 264.7 cell line, treated with 25 mM myricetin or co-administered with the PI3K/Akt inhibitor LY294002 for a period of 24 h. In both in vivo and in vitro settings, quantification of inflammation factor levels was conducted using western blotting, real-time qPCR and ELISA. In db/db mice, administration of myricetin led to a mitigating effect on DN-induced renal dysfunction and fibrosis. Notably, we observed a significant reduction in expressions of the kidney injury markers kidney injury molecule-1 and neutrophil gelatinase associated lipocalin, along with a decrease in expressions of inflammatory cytokine-related factors. Furthermore, myricetin treatment effectively inhibited the up-regulation of tumor necrosis factor-alpha, interleukin-6, and interluekin-1β induced by high glucose in RAW 264.7 cells. Additionally, myricetin modulated the M1-type polarization of the RAW 264.7 cells. Molecular docking and bioinformatic analyses revealed Akt as the target of myricetin. The protective effect of myricetin was nullified upon blocking the polarization of RAW 264.7 via inhibition of PI3K/Akt activation using LY294002. This study demonstrated that myricetin effectively mitigates kidney injury in DN mice through the regulation of macrophage polarization via the PI3K/Akt signaling pathway.

ARID1 and BRG1 Expression in Endometrial Cancer.

Endometrial cancer (EC) is the predominant malignancy among gynecologic cancers and ranks fourth among all types of cancer. Recently, researchers have focused on the development of new prognostic biomarkers. Subunits of the SWI/SNF protein complex, like the ARID1 and BRG1, have been associated with the development of endometrial cancer. The present study aimed to evaluate the expression patterns of ARID1A and BRG1 in a collection of endometrioid adenocarcinomas of the uterus using immunohistochemistry. The study comprised a total of thirty-three individuals diagnosed with stage I endometrioid endometrial cancer, treated with radical hysterectomy. The histological material was then examined to assess the cytoplasmic and nuclear expression of the proteins. ARID1A exhibited expression in both the cytoplasm and nucleus of cancer cells, whereas BRG1 was mainly expressed in the nuclei. In addition, ARID1A exhibited a notable decrease in expression in grade 3 histology, with no significant correlation with the depth of myometrial invasion. The reduced expression was highly related to tumor expansion into the endocervix. The findings demonstrated a total absence of ARID1A expression in 27% of endometrioid carcinomas, with a significant reduction in expression in an additional 51% of cancer cells. These findings align with the most recent published data. In contrast, in the current study, BRG1 was rarely down-regulated and was extensively expressed in the majority of endometrioid carcinomas, preventing the possibility of statistical analysis. In summary, ARID1A expression loss can be used as a biomarker to guide post-operative therapy; however, further investigation is needed, especially for early-stage endometrial cancer.

Abstract A116: TSC1 mutant bladder cancer is characterized by a TSC-associated gene expression signature due to TFE3 transcriptional activity

Abstract Background: Mutations and inactivation of the tumor suppressor gene TSC1 are recurrent (6-10%) events in invasive bladder cancer, but the mechanism by which TSC1 loss promotes bladder cancer development beyond mTORC1 activation is uncertain. The purpose of this study was to assess the functional effects of TSC1 loss in bladder cancer and uncover new therapeutic targets for patients with TSC1 mutations. Materials and methods: We performed differential gene expression and pathway analyses using The Cancer Genome Atlas (TCGA) expression data for TSC1-mutated bladder cancer (TSC1mt-BLCA, n=26) and TSC1 wild-type tumors (TSC1wt-BLCA, n=382) and compared them to an internal cohort of TSC1/TSC2-mutant tumors (n=48). Transcriptomic, epigenetic, and functional analyses, including RNA-seq, H3K27ac ChIP-seq, TFE3 CUT&RUN, ATAC-seq and TFE3 knock-out using CRISPR/Cas9 were conducted on TSC1-mt/wt BLCA cell lines. Results: Comparison of TSC1mt-BLCA and TSC1wt-BLCA TCGA tumors identified 26 genes upregulated in TSC1mt-BLCA out of 60 genes commonly upregulated in Tuberous Sclerosis Complex (TSC) syndromic tumors. Among them, GPNMB showed the greatest increase in expression (median fold change 9.8). GSEA and DESeq2 analyses implicated both mTORC1 hyperactivation and increased lysosomal gene expression in TSC1mt-BLCA. Expression differences in several genes, including GPNMB, and in pS6 were confirmed by immunohistochemistry (IHC) of 5 independent BWH TSC1mt-BLCA and TSC1wt-BLCA specimens each. TFE3, a key regulator of lysosomal gene expression, was elevated in expression and localized to the nucleus in TSC1mt-BLCA by IHC. Molecular studies of TSC1-mt/wt BLCA isogenic cell lines (HCV29, RT4) recapitulated the phenotype found in human tumors. TFE3 was both post-translationally modified (assessed by immunoblot) and predominantly nuclear in TSC1-null cell lines compared to TSC1wt cells, and the localization was partially reversed by rapamycin treatment leading to reduced expression of lysosomal genes. TSC1mt HCV29 cells showed higher expression of multiple genes increased in TSC1mt-BLCA tumors (GPNMB, SQSTM1, GNPDA1). TFE3 knock-out HCV29 clones showed markedly reduced growth, which was not seen with TFE3 KO in TSC1-addback HCV29 cells. GSEA of RNA-seq data indicated that TFE3 KO led to significant reduction in expression of lysosome genes, as well as those involved in ribosome synthesis, DNA replication and DNA excision repair processes. TFE3 CUT&RUN confirmed that TFE3 binds to promoter regions of those genes, thereby directly regulating these pathways. In contrast, TFE3 KO led to an increase in inflammatory and cellular stress genes that could impede TSC1mt cell growth. Conclusions: Our findings show that TSC1mt-BLCA tumors and cell lines have a transcriptional signature similar to that of TSC syndromic tumors and show nuclear localization and transcriptional activation of TFE3. Aberrant TFE3 activation likely contributes to TSC1mt-BLCA development and may therefore be amenable to targeted therapy. Citation Format: Magdalena Losko, Clemens K Probst, Elio Adib, Heng Du, Michelle Hirsch, Krinio Giannikou, David J Kwiatkowski. TSC1 mutant bladder cancer is characterized by a TSC-associated gene expression signature due to TFE3 transcriptional activity [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A116.

Abstract 17334: Association of BIN1 Deletion With Electrical and Structural Remodeling in a Transgenic BIN1 KO Mouse Model of Heart Failure-Novel Option for Effective Therapy Using VK-II-86

Introduction: Cardiac deletion of Bridging Integrator 1 (BIN1) membrane protein produces an age-related cardiomyopathy in mice. Our hypothesis was to determine whether electrical accompanies this structural remodeling and examine the utility of VK-II-86, a structural analog of carvedilol with minimum β-blocking activity, as a potential antiarrhythmic therapeutic strategy. Methods: A cardiac-specific transgenic BIN1 KO mouse was employed. Structural and electrical cardiac changes were assessed using echocardiography and EKG (Visual Sonics-Vevo Heart Image). Murine ventricular cardiomyocytes were studied using patch-clamp techniques to examine changes in ion channel function and to study the effects of VK-II-86 on the action potential (AP). Results: Loss of BIN1 (KO) significantly reduced Left Ventricular Ejection Fraction (LVEF) and Cardiac Output (CO) when compared to WT mice, with a relative reduction of nearly 20% and 35% in EF and CO, respectively. Heterozygotic mice (HET) also exhibited significant reduction in EF and CO compared to WT mice. Loss of BIN1 (KO and HET) significantly prolonged the QT interval on surface ECG by approximately 15%. This finding correlates with the increase in AP duration (APD) demonstrated in ventricular cardiomyocytes using current clamp. BIN1 deficient hearts displayed significant reduction in expression of I to , I K1 and peak I Na (80%, 40% and 20% respectively) as well as augmented expression of late I Na (50%). This electrical remodeling is likely responsible for the increased expression of early (EAD) and late (DAD) afterdepolarization observed in APs. In BIN1 deficient ventricular cardiomyocytes, the addition of 1 μM VK-II-86 prevented the development of APD prolongation and suppressed EAD and DAD development. Conclusions: Our study adds to the understanding the role of BIN1. We demonstrate the first-time electrical remodeling in the form of QT and APD prolongation associated with BIN1 deficiency, due to reduced I to and I K1 and increase in late I Na , an increase in EAD and DAD events. Additionally, VK-II-86 is shown to normalize APD in isolated cardiomyocytes and suppress afterdepolarization events, making it a potentially novel and effective therapeutic strategy in HF associated with BIN1 deficiency.

6-hydroxydopamine affects multiple pathways to induce cytotoxicity in differentiated LUHMES dopaminergic neurons

The debilitating effects of Parkinson's disease (PD) progress over time and are pathophysiologically characterized by the formation of Lewy bodies due to the accumulation of α-synuclein aggregates resulting in the death of dopaminergic neurons. In the present study, we determined cell death pathways activated by acute exposure to 6-hydroxydopamine (6-OHDA) in differentiated LUHMES cells empirically followed by a 24 h toxin free interval, henceforth termed as washout/recovery period. Acute 6-OHDA exposure led to morphological changes in LUHMES cells and resulted in significant loss of neurite length and neurite thickness. Generation of reactive oxygen species and loss of mitochondrial membrane potential in the neuronal processes were persistent even after the recovery period. Our results show that 6-OHDA exposure leads to significant reduction in expression of mitochondrial OXPHOS complexes I, II, and IV and activation of caspase mediated apoptotic cell death cascade as observed by enhanced protein expression of cleaved-PARP-1 and cleaved-Caspase-3. Immunofluorescence microscopy approach confirmed that cell death occurs independent of the AIF translocation to the nucleus. Our experimental model, led to a ∼5-fold lower α-synuclein monomer expression and, interestingly, resulted in loss of protein ubiquitination in whole cell lysates. Altogether, this work provides evidence of multiple pathways targeted by 6-OHDA in differentiated LUHMES cells and expands research avenues for addressing the knowledge gap regarding the effect of 6-OHDA in the ubiquitin proteasome system for PD therapies.

Infection pre-Ad26.COV2.S-vaccination primes greater class switching and reduced CXCR5 expression by SARS-CoV-2-specific memory B cells

Neutralizing antibodies strongly correlate with protection for COVID-19 vaccines, but the corresponding memory B cells that form to protect against future infection are relatively understudied. Here we examine the effect of prior SARS-CoV-2 infection on the magnitude and phenotype of the memory B cell response to single dose Johnson and Johnson (Ad26.COV2.S) vaccination in South African health care workers. Participants were either naïve to SARS-CoV-2 or had been infected before vaccination. SARS-CoV-2-specific memory B-cells expand in response to Ad26.COV2.S and are maintained for the study duration (84 days) in all individuals. However, prior infection is associated with a greater frequency of these cells, a significant reduction in expression of the germinal center chemokine receptor CXCR5, and increased class switching. These B cell features correlated with neutralization and antibody-dependent cytotoxicity (ADCC) activity, and with the frequency of SARS-CoV-2 specific circulating T follicular helper cells (cTfh). Vaccination-induced effective neutralization of the D614G variant in both infected and naïve participants but boosted neutralizing antibodies against the Beta and Omicron variants only in participants with prior infection. In addition, the SARS-CoV-2 specific CD8+ T cell response correlated with increased memory B cell expression of the lung-homing receptor CXCR3, which was sustained in the previously infected group. Finally, although vaccination achieved equivalent B cell activation regardless of infection history, it was negatively impacted by age. These data show that phenotyping the response to vaccination can provide insight into the impact of prior infection on memory B cell homing, CSM, cTfh, and neutralization activity. These data can provide early signals to inform studies of vaccine boosting, durability, and co-morbidities.

Conditional Loss of MEF2C Expression in Osteoclasts Leads to a Sex-Specific Osteopenic Phenotype.

Myocyte enhancement factor 2C (MEF2C) is a transcription factor studied in the development of skeletal and smooth muscles. Bone resorption studies have exhibited that the reduced expression of MEF2C contributes to osteopetrosis and the dysregulation of pathological bone remodeling. Our current study aims to determine how MEF2C contributes to osteoclast differentiation and to analyze the skeletal phenotype of Mef2c-cKO mice (Cfms-cre; Mef2cfl/fl). qRT-PCR and Western blot demonstrated that Mef2c expression is highest during the early days of osteoclast differentiation. Osteoclast genes, including c-Fos, c-Jun, Dc-stamp, Cathepsin K, and Nfatc1, had a significant reduction in expression, along with a reduction in osteoclast size. Despite reduced CTX activity, female Mef2c cKO mice were osteopenic, with decreased bone formation as determined via a P1NP ELISA, and a reduced number of osteoblasts. There was no difference between male WT and Mef2c-cKO mice. Our results suggest that Mef2c is critical for osteoclastogenesis, and that its dysregulation leads to a sex-specific osteopenic phenotype.

PP4 deficiency contributes to DEP exacerbated epithelial barrier dysfunction and airway inflammation in asthmatic patients

Abstract Diesel exhaust particles (DEP) emitted from motor vehicle or heavy-duty industries is thought to be the major source of air pollutants that lead to the rapid increase and worsening of allergic disease, such as asthma. In asthma, exposure to DEP has been linked to aberrant epithelial barrier integrity, which leads to the promotion of allergen delivery into the subepithelia and induced alarmins (IL-33, IL-25 and thymic stromal lymphopoietin (TSLP)) release to promote Th2-mediated inflammation. However, it is still not known the detail mechanism of airway epithelial barrier in response to DEP. In this study, we fund that PP4 expression was decreased in DEP-challenged human bronchial epithelial cells and air-pollution animal model. Moreover, silencing PP4 decreased E-cadherin and barrier integrity through and activated Src kinase and increased expression of Slug. Sequentially, transactivating the EGFR phosphorylation led to increased alarmin synthesis. Overexpression of PP4 wild type, but not phosphatase mutant, prevented DEP-induced loss of airway epithelial E-cadherin expression and decreased alarmin release, suggested that phosphatase activity is critical to maintain epithelial integrity and alarmin production. Primary human bronchial epithelial cells (HBECs) from mild and severe asthmatic patients showed a significantly low TJ integrity in ALI cultures in response to DEP, compared with HBECs from healthy subjects. Our data demonstrate that exposure to DEP causes a significant reduction in expression of PP4 leading to decreased epithelial barrier function might accelerate the allergen-induced airway inflammatory response in asthma. Supported by grants from (MOST 110-2320-B-038-065-MY3) from the Ministry of Science and Technology of Taiwan.

Abstract CT136: An open-label phase I/IIa study to evaluate the safety and efficacy of CCS1477 as monotherapy and in combination in patients with advanced hematological malignancies

Abstract Background Inobrodib (CCS1477) is a first in class potent, selective, and orally bioavailable inhibitor of the bromodomains of p300 and CBP, two closely related histone acetyl transferases with oncogenic roles in hematological malignancies. In pre-clinical studies inobrodib potently inhibited cell proliferation in acute myeloid leukemia (AML), multiple myeloma (MM) and non-Hodgkin lymphoma (NHL) cell lines. Inobrodib demonstrated dose-dependent efficacy in corresponding xenograft models, eliciting tumor regression at the highest doses. These effects were accompanied by significant reductions in expression of MYC, MYB and IRF4. Low doses of inobrodib also demonstrated good efficacy when added to standard-of-care treatments, providing a strong rationale for combination treatment in patients. Inobrodib represents a novel and differentiated approach and offers a potential new therapeutic option for patients who have relapsed or are refractory to current standard of care therapies in AML, higher risk MDS, MM or NHL. Study Design and Methods NCT04068597 is an adaptive multi-arm/multi-stage trial allowing exploration of p300/CBP inhibition as monotherapy or in combination with different agents across multiple indications including AML/higher risk MDS, MM, and NHL. The trial was initiated as a dose escalation rolling 6 design separately in AML/MDS and MM/NHL to ensure tolerability is explored separately across groups of indications, with the possibility to expand in monotherapy across different indications. Key inclusion criteria include patients with confirmed relapsed or refractory disease, with patients having received standard therapy (typically at least two prior lines of therapy). Response criteria are assessed using standard methodologies for the different indications. Blood and tumor samples are collected for exploratory biomarker analysis to understand mechanisms of response to treatment or disease progression. The recommended phase 2 dose/schedule has been determined, and monotherapy expansion arms are currently open in selected indications. Cohorts investigating dose escalation with standard of care agents pomalidomide/dexamethasone in MM as well azacytidine with or without venetoclax in AML or MDS are currently enrolling, with the possibility of expansion for promising combinations. An additional ‘rescue’ cohort for MM patient who failed inobrodib monotherapy will be used to determine whether addition of pomalidomide with or without dexamethasone may reverse resistance to inobrodib. This cohort will also explore tolerability and clinical activity of steroid-sparing combination regimen. Citation Format: Tomasz Knurowski, Emma Searle, Karen Clegg, Neil Pegg, William West, Debbie Haynes, Kristopher Frese, Tim C. Somervaille. An open-label phase I/IIa study to evaluate the safety and efficacy of CCS1477 as monotherapy and in combination in patients with advanced hematological malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT136.

Expression and analysis of CX3CL1 chemokine and CD57+ lymphocytes in oral squamous cell carcinoma and their correlation with clinicopathologic features.

CX3CL1 exhibits chemoattraction for T-cells, monocytes, and CD57+ natural killer cells mediating antitumor immunity. The role of CX3CL1 has been studied in tumors of the breast, lung, colon, pancreas, prostate, etc. The current study was undertaken to understand the importance of CX3CL1 and its correlation with CD57+ cells in oral squamous cell carcinoma (OSCC). Seventy-five primary OSCC were staged and histopathologically graded, followed by immunohistochemistry for CX3CL1 and CD57. Mann-Whitney U-test, Kruskal-Wallis test, Post hoc Bonferroni test, and Pearson's correlation coefficient were applied. CX3CL1 assessment within the tumor cells was high in 62.66% of cases, and the CD57 Labeling Index (LI) varied over a wide range of 8.2-111.6. A statistically significant reduction in expression of both CX3CL1 and CD57 was observed with an increase in histologic grade (p = 0.021 and 0.038, respectively). It is concluded that CX3CL1 and CD57 may be important players in the immune surveillance of OSCC. Further studies with detailed follow-up for the overall survival of patients will help in studying the diagnostic, prognostic, and therapeutic roles of CX3CL1 in OSCC.

Smooth muscle αv integrins regulate vascular fibrosis via CD109 downregulation of TGF-β signalling.

αv integrins are implicated in fibrosis in a number of organs through their ability to activate TGF-β. However their role in vascular fibrosis and collagen accumulation is only partially understood. Here we have used αv conditional knockout mice and cell lines to determine how αv contributes to vascular smooth muscle cell (VSMC) function in vascular fibrosis and the role of TGF-β in that process. Angiotensin II (Ang II) treatment causes upregulation of αv and β3 expression in the vessel wall, associated with increased collagen deposition. We found that deletion of αv integrin subunit from VSMCs (αv SMKO) protected mice against angiotensin II-induced collagen production and assembly. Transcriptomic analysis of the vessel wall in αv SMKO mice and controls identified a significant reduction in expression of fibrosis and related genes in αv SMKO mice. In contrast, αv SMKO mice showed prolonged expression of CD109, which is known to affect TGF-β signalling. Using cultured mouse and human VSMCs, we showed that overexpression of CD109 phenocopied knockdown of αv integrin, attenuating collagen expression, TGF-β activation, and Smad2/3 signalling in response to angiotensin II or TGF-β stimulation. CD109 and TGF-β receptor were internalized in early endosomes. We identify a role for VSMC αv integrin in vascular fibrosis and show that αv acts in concert with CD109 to regulate TGF-β signalling.

Downregulation of Nrf2 in the Hippocampus Contributes to Postoperative Cognitive Dysfunction in Aged Rats by Sensitizing Oxidative Stress and Neuroinflammation.

Postoperative cognitive dysfunction (POCD) is a recognized clinical complication defined by a new cognitive impairment arising after a surgical procedure. Elderly patients are especially vulnerable to cognitive impairment after surgical operations, but the underlying mechanisms remain elusive. Oxidative stress and neuroinflammation in the hippocampus, a brain region involved in memory formation, are considered as major contributors to the development of POCD. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a master regulator of endogenous inducible defense system, plays a crucial role in protecting cells against oxidative stress and inflammation by enhancing transcription of antioxidant and anti-inflammatory target genes. Here, we examined whether aging downregulates Nrf2 in the hippocampus and, if so, whether downregulation of hippocampal Nrf2 contributes to POCD in aging. Young and aged rats underwent abdominal surgery or sham operation. One week later, cognitive function was assessed, and brains were collected for molecular studies. Compared with young sham rats, aged sham rats exhibited a significant reduction in expression of Nrf2 in the hippocampus. Interestingly, the expression of Nrf2 downstream target genes and levels of reactive oxygen species (ROS) and proinflammatory cytokines in the hippocampus as well as cognitive function were comparable between aged sham and young sham rats. After abdominal surgery, young rats showed significant upregulation of Nrf2 and its target genes in the hippocampus. However, aged rats did not show changes in expression of Nrf2 and its target genes but had increased levels of ROS and proinflammatory cytokines in the hippocampus, along with cognitive impairment as indicated by reduced contextual freezing time. Moreover, upregulation of hippocampal Nrf2 in aged rats with intracerebroventricular infusion of a Nrf2 activator reduced levels of ROS and proinflammatory cytokines in the hippocampus, ameliorating cognitive dysfunction after surgery. The results suggest that aging-induced downregulation of Nrf2 in the hippocampus causes the failure to activate Nrf2-regulated antioxidant defense system in response to surgical insult, which contributes to POCD by sensitizing oxidative stress and neuroinflammation. Nrf2 activation in the brain may be a novel strategy to prevent the cognitive decline in elderly patients after surgery.

IPSC-Derived Pancreatic Progenitors Lacking FOXA2 Reveal Alterations in miRNA Expression Targeting Key Pancreatic Genes

Recently, we reported that forkhead box A2 (FOXA2) is required for the development of human pancreatic α- and β-cells. However, whether miRNAs play a role in regulating pancreatic genes during pancreatic development in the absence of FOXA2 expression is largely unknown. Here, we aimed to capture the dysregulated miRNAs and to identify their pancreatic-specific gene targets in pancreatic progenitors (PPs) derived from wild-type induced pluripotent stem cells (WT-iPSCs) and from iPSCs lacking FOXA2 (FOXA2–/–iPSCs). To identify differentially expressed miRNAs (DEmiRs), and genes (DEGs), two different FOXA2–/–iPSC lines were differentiated into PPs. FOXA2–/– PPs showed a significant reduction in the expression of the main PP transcription factors (TFs) in comparison to WT-PPs. RNA sequencing analysis demonstrated significant reduction in the mRNA expression of genes involved in the development and function of exocrine and endocrine pancreas. Furthermore, miRNA profiling identified 107 downregulated and 111 upregulated DEmiRs in FOXA2–/– PPs compared to WT-PPs. Target prediction analysis between DEmiRs and DEGs identified 92 upregulated miRNAs, predicted to target 1498 downregulated genes in FOXA2–/– PPs. Several important pancreatic TFs essential for pancreatic development were targeted by multiple DEmiRs. Selected DEmiRs and DEGs were further validated using RT-qPCR. Our findings revealed that FOXA2 expression is crucial for pancreatic development through regulating the expression of pancreatic endocrine and exocrine genes targeted by a set of miRNAs at the pancreatic progenitor stage. These data provide novel insights of the effect of FOXA2 deficiency on miRNA-mRNA regulatory networks controlling pancreatic development and differentiation.Graphical

Proviral ALV-LTR Sequence Is Essential for Continued Proliferation of the ALV-Transformed B Cell Line.

Avian leukosis virus (ALV) induces B-cell lymphomas and other malignancies in chickens through insertional activation of oncogenes, and c-myc activation has been commonly identified in ALV-induced tumors. Using ALV-transformed B-lymphoma-derived HP45 cell line, we applied in situ CRISPR-Cas9 editing of integrated proviral long terminal repeat (LTR) to examine the effects on gene expression and cell proliferation. Targeted deletion of LTR resulted in significant reduction in expression of a number of LTR-regulated genes including c-myc. LTR deletion also induced apoptosis of HP45 cells, affecting their proliferation, demonstrating the significance of LTR-mediated regulation of critical genes. Compared to the global effects on expression and functions of multiple genes in LTR-deleted cells, deletion of c-myc had a major effect on the HP45 cells proliferation with the phenotype similar to the LTR deletion, demonstrating the significance of c-myc expression in ALV-induced lymphomagenesis. Overall, our studies have not only shown the potential of targeted editing of the LTR for the global inhibition of retrovirus-induced transformation, but also have provided insights into the roles of LTR-regulated genes in ALV-induced neoplastic transformation.