KDM5C-Mediated Recruitment of BRD4 to Chromatin Regulates Enhancer Activation and BET Inhibitor Sensitivity

The BET family member BRD4 is a bromodomain-containing protein that plays a vital role in driving oncogene expression. Given their pivotal role in regulating oncogenic networks in various cancer types, BET inhibitors (BETi) have been developed, but the clinical application has been impeded by dose-limiting toxicity and resistance. Understanding the mechanisms of BRD4 activity and identifying predictive biomarkers could facilitate the successful clinical use of BETis. Herein, we show that KDM5C and BRD4 cooperate to sustain tumor cell growth. Mechanistically, KDM5C interacted with BRD4 and stimulated BRD4 enhancer recruitment. Moreover, binding of the BRD4 C-terminus to KDM5C stimulated the H3K4 demethylase activity of KDM5C. The abundance of both KDM5C-associated BRD4 and H3K4me1/3 determined the transcriptional activation of many oncogenes. Notably, depletion or pharmacologic degradation of KDM5C dramatically reduced BRD4 chromatin enrichment and significantly increased BETi efficacy across multiple cancer types in both tumor cell lines and patient-derived organoid models. Furthermore, targeting KDM5C in combination with BETi suppressed tumor growth in vivo in a xenograft mouse model. Collectively, this work reveals a KDM5C-mediated mechanism by which BRD4 regulates transcription, providing a rationale for incorporating BETi into combination therapies with KDM5C inhibitors to enhance treatment efficacy.

SIGNIFICANCE

BRD4 is recruited to enhancers in a bromodomain-independent manner by binding KDM5C and stimulates KDM5C H3K4 demethylase activity, leading to synergistic effects of BET and KDM5C inhibitor combinations in cancer.

Clinical features and outcomes of advanced HER2+ esophageal/GEJ cancer with brain metastasis

BACKGROUND

Brain metastasis (BRM) is uncommon in gastroesophageal cancer. As such, clinicopathologic and molecular determinants of BRM and impact on clinical outcome remain incompletely understood.

METHODS

We retrospectively analyzed clinicopathologic data from advanced esophageal/gastroesophageal junction (E/GEJ) patients at Johns Hopkins from 2003 to 2021. We investigated the association between several clinical and molecular features and the occurrence of BRM, with particular focus on human epidermal growth factor receptor 2 (HER2) overexpression. Survival outcomes and time to BRM onset were also evaluated.

RESULTS

We included 515 patients with advanced E/GEJ cancer. Tumors were 78.3% esophageal primary, 82.9% adenocarcinoma, 31.0% HER2 positive. Cumulative incidence of BRM in the overall cohort and within HER2+ subgroup was 13.8% and 24.3%, respectively. HER2 overexpression was associated with increased risk of BRM [odds ratio 2.45; 95% confidence interval (CI) 1.10-5.46]. On initial presentation with BRM, 50.7% had a solitary brain lesion and 11.3% were asymptomatic. HER2+ status was associated with longer median time to onset of BRM (14.0 versus 6.3 months, P < 0.01), improved median progression free survival on first-line systemic therapy (hazard ratio 0.35, 95% CI 0.16-0.80), and improved median overall survival (hazard ratio 0.20, 95% CI 0.08-0.54) in patients with BRM.

CONCLUSION

HER2 overexpression identifies a gastroesophageal cancer molecular subtype that is significantly associated with increased risk of BRM, though with later onset of BRM and improved survival likely reflecting the impact of central nervous system-penetrant HER2-directed therapy. The prevalence of asymptomatic and solitary brain lesions suggests that brain surveillance for HER2+ patients warrants prospective investigation.

[Influential factors of non-motor symptoms prognosis in Parkinson's disease patients undergoing deep brain stimulation]

Objective: To investigate the effects of electrode activated contact location, volume of tissue activated (VTA) and age on non-motor symptoms, such as emotional symptoms and cognitive function, in Parkinson's disease (PD) patients with deep brain stimulation (DBS). Methods: PD patients who underwent DBS of subthalamic nucleus (STN) at the Department of Functional Neurosurgery of Beijing Tiantan Hospital from September 1, 2020 to August 31, 2022 were retrospectively enrolled. The International Parkinson and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), Montreal Cognitive Assessment (MoCA), and Mini-Mental State Examination Scales (MMSE) were used at the preoperative, 1-month and 12-month postoperative time points. In this study, patients were divided into middle-aged (age<60 years,n=39) and elderly (age≥60 years,n=62) groups to investigate the effect of age factor on the clinical outcome of surgery. Lead-DBS software was used to convert the patients' electrode reconstruction results into Montreal standard space, and the patients were divided into sensorimotor(n=43) and combined groups(n=53) according to the distribution of activation contact locations in the subzones of the STN. In addition, the patients were divided into a cognitive improvement group(n=57)and a cognitive deterioration group(n=44) based on the results of MoCA at 12 months. The positional information of the electrode activation contacts was collected and the VTA was calculated to analyze the effects on electrode activation electroshock location and activated tissue volume on patients' non-motor symptoms. Results: A total of 101 patients with PD were enrolled, including 46 males and 55 females, aged (62.6±8.4) years. Middle-aged patients had significantly higher MoCA scores, delayed recall scores, attention scores, and naming scores than older patients at 12 months postoperatively (all P<0.05). At 12-month follow-up, the improvement rate of MoCA score, HAMA score and HAMD score were -1.77%±20.36%, 39.65%±42.91% and 36.23%±45.45% respectively in sensorimotor group. At 12-month follow-up, the improvement rate of MoCA score, HAMA score and HAMD score was 11.69%±22.24%, 16.62%±68.10% and 2.30%±95.04% respectively in the combined group, and the difference between the two groups was statistically significant (MoCA: P=0.002; HAMA: P=0.040; HAMD: P=0.033) The distribution of VTA in the sensory motor area and marginal area of the left hemisphere STN in patients with improved cognitive function was significantly smaller than that in the deterioration group [(60.53±52.04)mm³vs (84.55±61.00)mm³, P=0.035; (41.81±33.36)mm³vs (59.05±45.46)mm³, P=0.030]. Conclusion: The effect of STN-DBS on emotional symptoms and cognitive function in PD patients is influenced by various factors and is closely related to the patient's age, electrode activation contact location and VTA.

PRMT2 promotes HIV-1 latency by preventing nucleolar exit and phase separation of Tat into the Super Elongation Complex

The HIV-1 Tat protein hijacks the Super Elongation Complex (SEC) to stimulate viral transcription and replication. However, the mechanisms underlying Tat activation and inactivation, which mediate HIV-1 productive and latent infection, respectively, remain incompletely understood. Here, through a targeted complementary DNA (cDNA) expression screening, we identify PRMT2 as a key suppressor of Tat activation, thus contributing to proviral latency in multiple cell line latency models and in HIV-1-infected patient CD4+ T cells. Our data reveal that the transcriptional activity of Tat is oppositely regulated by NPM1-mediated nucleolar retention and AFF4-induced phase separation in the nucleoplasm. PRMT2 preferentially methylates Tat arginine 52 (R52) to reinforce its nucleolar sequestration while simultaneously counteracting its incorporation into the SEC droplets, thereby leading to its functional inactivation to promote proviral latency. Thus, our studies unveil a central and unappreciated role for Tat methylation by PRMT2 in connecting its subnuclear distribution, liquid droplet formation, and transactivating function, which could be therapeutically targeted to eradicate latent viral reservoirs.

Proof-of-Concept and Characterization of Photosynthetic Bacteria as Radiation Enhancers

PURPOSE/OBJECTIVE(S)

Molecular O2 is a potent chemical radiosensitizer. Re-sensitizing hypoxic tumor tissues with O2 can enhance the therapeutic efficacy of ionizing radiation. Photosynthetic cyanobacteria (S. elongatus) or cyanos are currently being explored for various bioengineering applications due to their ability to produce oxygen when exposed to light. Here, we explore the use of these bacteria to replenish molecular O2 content inside hypoxic tumors, which in turn will enhance the effect of radiation. To assess the feasibility of this approach, we used A549 lungs cancer cell spheroids as models, which are three-dimensional (3D) in vitro cell aggregates that mimic tumors in terms of oxygen and nutrient gradients.

MATERIALS/METHODS

The cyanos were grown in 12:12h light /dark conditions in a bacterial shaker incubator (37ºC and 150 rpm). Biocompatibility of cyanos co-cultured withA549 monolayers and spheroids was estimated using the MTT assay and Calcein AM staining. The level of hypoxia content in the spheroids were measured using the Image IT green hypoxia dye. Spheroids co-cultured with cyanos were subjected to full spectrum lights for different time periods. After light incubation, different dosages of radiation (4, 6 and 12 Gy) were delivered to the spheroids using an X-ray irradiator (225 kBp, 13 mA). Post irradiation, the spheroids were harvested and analyzed based on Nuc green dye staining to estimate the dead cell population and clonogenic survival to estimate the post-therapy survival fraction.

RESULTS

Under exposure to full spectrum LED light, cyanos increased the concentration of dissolved O2 in the medium, eventually reaching fourfold higher levels (i.e., ∼240% of dissolved O2). Addition of cyanos to mammalian cell cultures did not result in detectable toxicity for either cellular monolayers or 3D spheroids. Cell viability was 100% even at the highest tested concentration of 1 × 107 number of cyanos cultured with 10,000 A549 cells. This confirmed the biocompatibility of the cyanos in cell culture environment. Post irradiation, as depicted from the Nuc green dye staining, was twofold higher (p<0.01) in spheroids co-cultured with cyanos and exposed to light. Surprisingly, in the clonogenic assay, this group of spheroids exhibited a higher survival fraction compared to the control group. This unexpected outcome warrants further investigation of the potentially radioprotecting effect of cyanos. Altogether, this supports the potential therapeutic efficacy of the cyanos in hypoxic tumors.

CONCLUSION

Cyanos in the presence of light are effective in enhancing radiation-induced cell death. While clinical translation is still far down the road, such a method could be employed in the context of brachytherapy or superficial radiotherapy to overcome tumor hypoxia.

R-loop-dependent promoter-proximal termination ensures genome stability

The proper regulation of transcription is essential for maintaining genome integrity and executing other downstream cellular functions1,2. Here we identify a stable association between the genome-stability regulator sensor of single-stranded DNA (SOSS)3 and the transcription regulator Integrator-PP2A (INTAC)4-6. Through SSB1-mediated recognition of single-stranded DNA, SOSS-INTAC stimulates promoter-proximal termination of transcription and attenuates R-loops associated with paused RNA polymerase II to prevent R-loop-induced genome instability. SOSS-INTAC-dependent attenuation of R-loops is enhanced by the ability of SSB1 to form liquid-like condensates. Deletion of NABP2 (encoding SSB1) or introduction of cancer-associated mutations into its intrinsically disordered region leads to a pervasive accumulation of R-loops, highlighting a genome surveillance function of SOSS-INTAC that enables timely termination of transcription at promoters to constrain R-loop accumulation and ensure genome stability.

G-quadruplex in hepatitis B virus pregenomic RNA promotes its translation

Hepatitis B virus (HBV) is a hepatotropic DNA virus that has a very compact genome. Due to this genomic density, several distinct mechanisms are used to facilitate the viral life cycle. Recently, accumulating evidence show that G-quadruplex (G4) in different viruses play essential regulatory roles in key steps of the viral life cycle. Although G4 structures in the HBV genome have been reported, their function in HBV replication remains elusive. In this study, we treated an HBV replication-competent cell line and HBV-infected cells with the G4 structure stabilizer pyridostatin (PDS) and evaluated different HBV replication markers to better understand the role played by the G4. In both models, we found PDS had no effect on viral precore RNA (pcRNA) or pre-genomic RNA (pgRNA), but treatment did increase HBeAg/HBc ELISA reads and intracellular levels of viral core/capsid protein (HBc) in a dose-dependent manner, suggesting post-transcriptional regulation. To further dissect the mechanism of G4 involvement, we used in vitro-synthesized HBV pcRNA and pgRNA. Interestingly, we found PDS treatment only enhanced HBc expression from pgRNA but not HBeAg expression from pcRNA. Our bioinformatic analysis and CD spectroscopy revealed that pgRNA harbors a conserved G4 structure. Finally, we introduced point mutations in pgRNA to disrupt its G4 structure and observed the resulting mutant failed to respond to PDS treatment and decreased HBc level in in vitro translation assay. Taken together, our data demonstrate that HBV pgRNA contains a G4 structure that plays a vital role in the regulation of viral mRNA translation.

Identification of Novel Dual-Target Estrogen Receptor α Degraders with Tubulin Inhibitory Activity for the Treatment of Endocrine-Resistant Breast Cancer

Endocrine resistance remains a significant problem in the clinical treatment of estrogen receptor α-positive (ERα+) breast cancer (BC). In this study, we developed a series of novel dual-functional ERα degraders based on a bridged bicyclic scaffold with selenocyano (SeCN) side chains. These compounds displayed potent ERα degradation and tubulin depolymerization activity. Among them, compounds 35s and 35t exhibited the most promising antiproliferative and ERα degradation activity in multiple ERα+ BC cell lines bearing either wild-type or mutant ERα. Meanwhile, compounds 35s and 35t disrupted the microtubule network by restraining tubulin polymerization, evidenced by 35t inducing cell cycle arrest in the G2/M phase. In MCF-7 and LCC2 xenograft models, compounds 35s and 35t remarkably suppressed tumor growth without noticeable poisonousness. Finally, this study provided guidance for developing new dual-target antitumor drug candidates for the ERα+ BC therapy, especially for the resistant variant.

SARS-CoV-2 nsp13 Restricts Episomal DNA Transcription without Affecting Chromosomal DNA

Nonstructural protein 13 (nsp13), the helicase of SARS-CoV-2, has been shown to possess multiple functions that are essential for viral replication, and is considered an attractive target for the development of novel antivirals. We were initially interested in the interplay between nsp13 and interferon (IFN) signaling, and found that nsp13 inhibited reporter signal in an IFN-β promoter assay. Surprisingly, the ectopic expression of different components of the RIG-I/MDA5 pathway, which were used to stimulate IFN-β promoter, was also mitigated by nsp13. However, endogenous expression of these genes was not affected by nsp13. Interestingly, nsp13 restricted the expression of foreign genes originating from plasmid transfection, but failed to inhibit them after chromosome integration. These data, together with results from a runoff transcription assay and RNA sequencing, suggested a specific inhibition of episomal but not chromosomal gene transcription by nsp13. By using different truncated and mutant forms of nsp13, we demonstrated that its NTPase and helicase activities contributed to the inhibition of episomal DNA transcription, and that this restriction required direct interaction with episomal DNA. Based on these findings, we developed an economical and convenient high-throughput drug screening method targeting nsp13. We evaluated the inhibitory effects of various compounds on nsp13 by the expression of reporter gene plasmid after co-transfection with nsp13. In conclusion, we found that nsp13 can specifically inhibit episomal DNA transcription and developed a high-throughput drug screening method targeting nsp13 to facilitate the development of new antiviral drugs. IMPORTANCE To combat COVID-19, we need to understand SARS-CoV-2 and develop effective antiviral drugs. In our study, we serendipitously found that SARS-CoV-2 nsp13 could suppress episomal DNA transcription without affecting chromosomal DNA. Detailed characterization revealed that nsp13 suppresses episomal gene expression through its NTPase and helicase functions following DNA binding. Furthermore, we developed a high-throughput drug screening system targeting SARS-CoV-2 nsp13. Compared to traditional SARS-CoV-2 drug screening methods, our system is more economical and convenient, facilitating the development of more potent and selective nsp13 inhibitors and enabling the discovery of new antiviral therapies.

Reversible bonding of microfluidics: Review and applications

With the development of microfluidic technology, new materials and fabrication methods have been constantly invented in the field of microfluidics. Bonding is one of the key steps for the fabrication of enclosed-channel microfluidic chips, which have been extensively explored by researchers globally. The main purpose of bonding is to seal/enclose fabricated microchannels for subsequent fluid manipulations. Conventional bonding methods are usually irreversible, and the forced detachment of the substrate and cover plate may lead to structural damage to the chip. Some of the current microfluidic applications require reversible bonding to reuse the chip or retrieve the contents inside the chip. Therefore, it is essential to develop reversible bonding methods to meet the requirements of various applications. This review introduces the most recent developments in reversible bonding methods in microfluidics and their corresponding applications. Finally, the perspective and outlook of reversible bonding technology were discussed in this review.

CDK12 and Integrator-PP2A complex modulates LEO1 phosphorylation for processive transcription elongation

Cyclin-dependent kinase 12 (CDK12) interacts with cyclin K to form a functional nuclear kinase that promotes processive transcription elongation through phosphorylation of the C-terminal domain of RNA polymerase II (Pol II). To gain a comprehensive understanding of CDK12's cellular function, we used chemical genetic and phosphoproteomic screening to identify a landscape of nuclear human CDK12 substrates, including regulators of transcription, chromatin organization, and RNA splicing. We further validated LEO1, a subunit of the polymerase-associated factor 1 complex (PAF1C), as a bona fide cellular substrate of CDK12. Acute depletion of LEO1, or substituting LEO1 phosphorylation sites with alanine, attenuated PAF1C association with elongating Pol II and impaired processive transcription elongation. Moreover, we discovered that LEO1 interacts with and is dephosphorylated by the Integrator-PP2A complex (INTAC) and that INTAC depletion promotes the association of PAF1C with Pol II. Together, this study reveals an uncharacterized role for CDK12 and INTAC in regulating LEO1 phosphorylation, providing important insights into gene transcription and its regulation.

Discovery of a Novel Class of PROTACs as Potent and Selective Estrogen Receptor α Degraders to Overcome Endocrine-Resistant Breast Cancer In Vitro and In Vivo

The estrogen receptor (ER) is a well-established target for endocrine therapies of ER-positive breast cancer (ER⁺ BC), but endocrine resistance limits the efficacy of clinical drugs. Using proteolysis targeting chimera (PROTAC) technology to degrade ERα may be an effective alternative to endocrine therapies. Herein, we disclose a novel series of potent and selective ERα PROTACs based on an oxabicycloheptane sulfonamide (OBHSA) scaffold, with no associated ERβ degradation. These PROTACs showed significant antiproliferation and ERα degradation activities against a broad spectrum of ER⁺ BC cells including tamoxifen-resistant and ERα mutant cell lines. Genomics analysis confirmed that these PROTACs inhibited the nascent RNA synthesis of ERα target genes and impaired genome-wide ERα binding. Compound ZD12 exhibited excellent antitumor potency and ERα degradation activity in both tamoxifen-sensitive and -resistant BC mice models, which are superior to fulvestrant. This study demonstrates the potential of these PROTACs as novel drug candidates for endocrine-resistant BC treatment.

The super elongation complex drives transcriptional addiction in MYCN-amplified neuroblastoma

MYCN amplification in neuroblastoma leads to aberrant expression of MYCN oncoprotein, which binds active genes promoting transcriptional amplification. Yet, how MYCN coordinates transcription elongation to meet productive transcriptional amplification and which elongation machinery represents MYCN-driven vulnerability remain to be identified. We conducted a targeted screen of transcription elongation factors and identified the super elongation complex (SEC) as a unique vulnerability in MYCN-amplified neuroblastomas. MYCN directly binds EAF1 and recruits SEC to enhance processive transcription elongation. Depletion of EAF1 or AFF1/AFF4, another core subunit of SEC, leads to a global reduction in transcription elongation and elicits selective apoptosis of MYCN-amplified neuroblastoma cells. A combination screen reveals SEC inhibition synergistically potentiates the therapeutic efficacies of FDA-approved BCL-2 antagonist ABT-199, in part due to suppression of MCL1 expression, both in MYCN-amplified neuroblastoma cells and in patient-derived xenografts. These findings identify disruption of the MYCN-SEC regulatory axis as a promising therapeutic strategy in neuroblastoma.

CDK13 phosphorylates the translation machinery and promotes tumorigenic protein synthesis

Cyclin-dependent kinase 13 (CDK13) has been suggested to phosphorylate RNA polymerase II and is involved in transcriptional activation. However, whether CDK13 catalyzes other protein substrates and how CDK13 contributes to tumorigenesis remain largely unclear. We here identify key translation machinery components, 4E-BP1 and eIF4B, as novel CDK13 substrates. CDK13 directly phosphorylates 4E-BP1 at Thr46 and eIF4B at Ser422; genetically or pharmacologically inhibiting CDK13 disrupts mRNA translation. Polysome profiling analysis shows that MYC oncoprotein synthesis strictly depends on CDK13-regulated translation in colorectal cancer (CRC), and CDK13 is required for CRC cell proliferation. As mTORC1 is implicated in 4E-BP1 and eIF4B phosphorylation, inactivation of CDK13 in combination with the mTORC1 inhibitor rapamycin further dephosphorylates 4E-BP1 and eIF4B and blocks protein synthesis. As a result, dual inhibition of CDK13 and mTORC1 induces more profound tumor cell death. These findings clarify the pro-tumorigenic role of CDK13 by direct phosphorylation of translation initiation factors and enhancing protein synthesis. Therefore, therapeutic targeting of CDK13 alone or in combination with rapamycin may pave a new way for cancer treatment.

[Exosomes secreted from human umbilical cord mesenchymal stem cells promote pancreatic ductal adenocarcinoma growth by transferring miRNAs]

Objective: To observe the effects of exosomes derived from human umbilical cord mesenchymal stem cells on the proliferation and invasion of pancreatic cancer cells, and to analyze the contents of exosomes and explore the mechanisms affecting pancreatic cancer cells. Methods: Exosomes extracted from human umbilical cord mesenchymal stem cells were added to pancreatic cancer cells BxPC3, Panc-1 and mouse models of pancreatic cancer, respectively. The proliferative activity and invasion abilities of BxPC3 and Panc-1 cells were measured by cell counting kit-8 (CCK-8) and Transwell assays. The expressions of miRNAs in exosomes were detected by high-throughput sequencing. GO and KEGG were used to analyze the related functions and the main metabolic pathways of target genes with high expressions of miRNAs. Results: The results of CCK-8 cell proliferation assay showed that the absorbance of BxPC3 and Panc-1 cells in the hucMSCs-exo group was significantly higher than that in the control group [(4.68±0.09) vs. (3.68±0.01), P<0.05; (5.20±0.20) vs. (3.45±0.17), P<0.05]. Transwell test results showed that the number of invasion cells of BxPC3 and Panc-1 in hucMSCs-exo group was significantly higher than that in the control group (129.40±6.02) vs. (89.40±4.39), P<0.05; (134.40±7.02) vs. (97.00±6.08), P<0.05. In vivo experimental results showed that the tumor volume and weight in the exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs-exo) group were significantly greater than that in the control group [(884.57±59.70) mm(3) vs. (695.09±57.81) mm(3), P<0.05; (0.94±0.21) g vs. (0.60±0.13) g, P<0.05]. High-throughput sequencing results showed that miR-148a-3p, miR-100-5p, miR-143-3p, miR-21-5p and miR-92a-3p were highly expressed. GO and KEGG analysis showed that the target genes of these miRNAs were mainly involved in the regulation of glucosaldehylation, and the main metabolic pathways were ascorbic acid and aldehyde acid metabolism, which were closely related to the development of pancreatic cancer. Conclusion: Exosomes derived from human umbilical cord mesenchymal stem cells can promote the growth of pancreatic cancer cells and the mechanism is related to miRNAs that are highly expressed in exosomes.

G-quadruplexes sense natural porphyrin metabolites for regulation of gene transcription and chromatin landscapes

BACKGROUND

G-quadruplexes (G4s) are unique noncanonical nucleic acid secondary structures, which have been proposed to physically interact with transcription factors and chromatin remodelers to regulate cell type-specific transcriptome and shape chromatin landscapes.

RESULTS

Based on the direct interaction between G4 and natural porphyrins, we establish genome-wide approaches to profile where the iron-liganded porphyrin hemin can bind in the chromatin. Hemin promotes genome-wide G4 formation, impairs transcription initiation, and alters chromatin landscapes, including decreased H3K27ac and H3K4me3 modifications at promoters. Interestingly, G4 status is not involved in the canonical hemin-BACH1-NRF2-mediated enhancer activation process, highlighting an unprecedented G4-dependent mechanism for metabolic regulation of transcription. Furthermore, hemin treatment induces specific gene expression profiles in hepatocytes, underscoring the in vivo potential for metabolic control of gene transcription by porphyrins.

CONCLUSIONS

These studies demonstrate that G4 functions as a sensor for natural porphyrin metabolites in cells, revealing a G4-dependent mechanism for metabolic regulation of gene transcription and chromatin landscapes, which will deepen our knowledge of G4 biology and the contribution of cellular metabolites to gene regulation.

Functional heart and brain changes in acute coronary syndromes

Aims

To investigate whether there are functional brain differences, or differences in global network measures, between patients with acute coronary syndrome (ACS) and non-obstructive coronary arteries and patients with an ST-elevation myocardial infarction (STEMI) and healthy controls.

Methods and results

In this single centre, prospective cohort study, all patients &lt;80 years who presented to a tertiary cardiac centre with a suspected acute coronary syndrome and who had non-obstructive coronary arteries on invasive angiography were approached for inclusion. Age and sex matched patients presenting with a STEMI and a further group of healthy volunteers were recruited as control groups. All patients received routine clinical care and investigations and underwent additional psychological questionnaires, cardiac magnetic resonance imaging and functional brain imaging within 14 days of admission. Image pre-processing and analysis was undertaken in a blinded fashion.

72 participants, in addition to 27 STEMI controls and 28 healthy controls, were recruited. Median age in the participant group was 57 years (IQR 47–66 years) and patients were scanned 6 days (IQR 3–8 days) from admission. Patients with ACS and non-obstructive arteries had increased functional connectivity in the default mode network and reduced connectivity in the central executive network compared to controls (Figure 1). They also had higher anxiety scores compared to STEMI and healthy controls and higher depression and stress scores compared to healthy controls (Figure 2). There was no difference in any global network measure between participants and age and sex matched controls however high anxiety or stress scores were associated with lower global efficiency in patients with ACS and non-obstructive coronary arteries but not in controls (Figure 2).

Conclusion

Patients with ACS and non-obstructive coronary arteries are distinct from both the STEMI and healthy population in terms of their psychological and neurofunctional state and this may have important future therapeutic implications for patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): James Tudor FoundationRosetrees Trust

Mussel-Inspired Hydrogels for Fluoride Delivery and Caries Prevention

Fluoride agents hold promise for the repair and prevention of caries lesions, but their interaction with enamel is often hampered and diminished because of the dynamic wet environment in the oral cavity, which affects the efficacy of fluoride delivery and limits treatment success. We herein developed a mussel-inspired wet adhesive fluoride system (denoted TS@NaF) fabricated by the self-assembly of tannic acid (TA), silk fibroin (SF), and sodium fluoride (NaF). TS@NaF demonstrated remarkable biological stability and biocompatibility, showed reliable wet adhesion, released fluoride ions (F−) topically, and induced significant deposition of calcium fluoride (CaF2) onto enamel in vitro. Furthermore, TS@NaF provided an anticaries effect in vitro and induced a detectable increase in enamel mineral density. Advanced fluoride-releasing bioadhesives are therefore promising candidates for caries prevention and highlight the great potential of mussel-inspired dental materials in clinical applications.

PCGF6 controls neuroectoderm specification of human pluripotent stem cells by activating SOX2 expression

Polycomb group (PcG) proteins are known to repress developmental genes during embryonic development and tissue homeostasis. Here, we report that PCGF6 controls neuroectoderm specification of human pluripotent stem cells (PSCs) by activating SOX2 gene. Human PSCs with PCGF6 depletion display impaired neuroectoderm differentiation coupled with increased mesendoderm outcomes. Transcriptome analysis reveals that de-repression of the WNT/β-catenin signaling pathway is responsible for the differentiation of PSC toward the mesendodermal lineage. Interestingly, PCGF6 and MYC directly interact and co-occupy a distal regulatory element of SOX2 to activate SOX2 expression, which likely accounts for the regulation in neuroectoderm differentiation. Supporting this notion, genomic deletion of the SOX2-regulatory element phenocopies the impaired neuroectoderm differentiation, while overexpressing SOX2 rescues the neuroectoderm phenotype caused by PCGF6-depletion. Together, our study reveals that PCGF6 can function as lineage switcher between mesendoderm and neuroectoderm in human PSCs by both suppression and activation mechanisms.

Variant Polycomb complexes can have tissue-specific roles during development. Here they show that PCGF6 controls lineage-specification in human PSCs by promoting neuroectoderm differentiation and repressing mesendoderm differentiation via distinct downstream targets.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Genome-Wide Native R-Loop Profiling by R-Loop Cleavage Under Targets and Tagmentation (R-Loop CUT&Tag)

R-loops are three-stranded nucleic acid structures that consist of a DNA-RNA hybrid and a displaced single-stranded DNA. R-loops occur during transcription and participate in multiple physiological processes such as DNA repair, modulating DNA topology, and regulation of gene transcription. Dysfunctional R-loops associate with several human diseases such as neurological disorders and cancer. Therefore, accurately and comprehensively profiling native R-loops is crucial to understand their functions under both physiological and pathological conditions. Here, we describe a convenient native R-loop profiling method, R-loop CUT&Tag, which combines a DNA-RNA hybrid sensor (GST-His₆-2 × HBD or S9.6 antibody) with a pA-Tn5-based cleavage under targets and tagmentation approach. R-loop CUT&Tag starts with 0.5 million cells and can sensitively detect native and specific R-loops at the promoter, gene body, and enhancer regions.

YTHDF1 promotes mRNA degradation via YTHDF1-AGO2 interaction and phase separation

Objectives

YTHDF1 is known as a m⁶A reader protein, and many researches of YTHDF1 focused on the regulation of mRNA translation efficiency. However, YTHDF1 is also related to RNA degradation, but how YTHDF1 regulates mRNA degradation is indefinite. Liquid‐liquid phase separation (LLPS) underlies the formation of membraneless compartments in mammal cells, and there are few reports focused on the correlation of RNA degradation with LLPS. In this research, we focused on the mechanism of YTHDF1 degraded mRNA through LLPS.

Materials and Methods

The CRISPR/Cas9 knock out system was used to establish the YTHDF1 knock out (YTHDF1‐KO) cell lines (HEK293 and HeLa) and METTL14 knock out (METTL14‐KO) cell line (HEK293). 4SU‐TT‐seq was used to check the half‐life changes of mRNAs. Actinomycin D and qPCR were used to test the half‐life changes of individual mRNA. RNA was stained with SYTO RNA‐select dye in wild type (WT) and YTHDF1‐KO HeLa cell lines. Co‐localization of YTHDF1 and AGO2 was identified by immunofluorescence. The interaction domain of YTHDF1 and AGO2 was identified by western blot. Phase separation of YTHDF1 was performed in vitro and in vivo. Fluorescence recovery after photobleaching (FRAP) was performed on droplets as an assessment of their liquidity.

Results

In this research, we found that deletion of YTHDF1 led to massive RNA patches deposited in cytoplasm. The results of 4SU‐TT‐seq showed that deletion of YTHDF1 would prolong the half‐life of mRNAs. Immunofluorescence data showed that YTHDF1 and AGO2 could co‐localize in P‐body, and Co‐IP results showed that YTHDF1 could interact with AGO2 through YT521‐B homology (YTH) domain. We confirmed that YTHDF1 could undergo phase separation in vitro and in vivo, and compared with AGO2, YTHDF1 was more important in P‐body formation. The FRAP results showed that liquid AGO2 droplets would convert to gel/solid when YTHDF1 was deleted. As AGO2 plays important roles in miRISCs, we also found that miRNA‐mediate mRNA degradation is related to YTHDF1.

Conclusions

YTHDF1 recruits AGO2 through the YTH domain. YTHDF1 degrades targeting mRNAs by promoting P‐body formation through LLPS. The deletion of YTHDF1 causes the P‐body to change from liquid droplets to gel/solid droplets, and form AGO2/RNA patches, resulting in a degradation delay of mRNAs. These findings reveal a previously unrecognized crosstalk between YTHDF1 and AGO2, raising a new sight of mRNA post‐transcriptional regulation by YTHDF1.

The spatial form periosteal-bone complex promotes bone regeneration by coordinating macrophage polarization and osteogenic-angiogenic events

Bone defects associated with soft tissue injuries are an important cause of deformity that threatens people’s health and quality of life. Although bone substitutes have been extensively explored, effective biomaterials that can coordinate early inflammation regulation and subsequent repair events are still lacking. We prepared a spatial form periosteal bone extracellular matrix (ECM) scaffold, which has advantages in terms of low immunogenicity, good retention of bioactive ingredients, and a natural spatial structure. The periosteal bone ECM scaffold with the relatively low-stiffness periosteum (41.6 ± 3.7 kPa) could inhibit iNOS and IL-1β expression, which might be related to actin-mediated YAP translocation. It also helped to promote CD206 expression with the potential influence of proteins related to immune regulation. Moreover, the scaffold combined the excellent properties of decalcified bone and periosteum, promoted the formation of blood vessels, and good osteogenic differentiation (RUNX2, Col 1α1, ALP, OPN, and OCN), and achieved good repair of a cranial defect in rats. This scaffold, with its natural structural and biological advantages, provides a new idea for bone healing treatment that is aligned with bone physiology.

•

We provided a spatial form periosteal-bone complex.

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The scaffold preserved major biological components and spatial structure.

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The periosteum part of the scaffold acted as a physical barrier.

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The scaffold participated in the transformation of the macrophage phenotype.

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The scaffold promoted osteogenesis and angiogenesis.

High accuracy measurement of the ground-state hyperfine splitting in a 113Cd+ microwave clock: erratum

We present an erratum to our Letter [Opt. Lett.40, 4249 (2015)OPLEDP0146-959210.1364/OL.40.004249]. This erratum corrects the nuclear Lande factor gI in Eq. (2). After correcting the error, the final ground-state hyperfine splitting frequency of the ¹¹³Cd⁺ ion is determined to be 15199862855.0287(10) Hz.

Diagnostic and prognostic role of peak troponin T in patients with acute coronary syndromes and non-obstructive coronary arteries

Background

Up to 10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood.

Purpose

The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA.

Methods

Consecutive patients with a working diagnosis of MINOCA from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. Peak troponin T was identified during the index admission and divided into deciles and quartiles for analysis. The primary endpoint was all-cause mortality.

Results

Among 796 patients undergoing CMR, 719 met the study criteria and had underwent a diagnostic quality scan. The peak Troponin T threshold for optimal diagnostic sensitivity and specificity was 211 ng/L. Peak troponin T ≥211 ng/L and time to CMR of ≤14 days has a sensitivity of 94%, specificity of 35%, PPV 57% and NPV 94% for the CMR making a diagnosis. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.65% (p&lt;0.001, 95% CI 3.38 – 3.91; R2 0.84; Figure 1).

If the troponin is in the lowest decile and the CMR is performed at ≤14 days, the diagnostic yield is still 72%. There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p=0.157), however mortality is significantly lower in the highest two troponin quartiles (6.9% versus 11.9%; p=0.009; Figure 2).

Conclusion

Peak troponin T is readily available during the index admission in patients presenting with MINOCA and provides useful diagnostic and prognostic information for the attending cardiologist.

Funding Acknowledgement

Type of funding sources: None. Figure 1. CMR diagnosis by troponin decileFigure 2. Mortality by troponin quartile

Sex and age differences in patients with acute coronary syndrome and non-obstructive coronary arteries: presentation and outcome

Aims

A substantial number of patients present with acute coronary syndrome (ACS) and non-obstructive coronary arteries. Sex and age differences in these patients are not well understood. This study aims to evaluate the impact of sex and age on clinical presentation and outcome in patients with ACS and non-obstructive coronary arteries, with either an ischaemic or non-ischaemic cause.

Methods and results

Consecutive patients with an ACS and non-obstructive coronary arteries (n=719) from a single tertiary centre underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE). The primary endpoint was all-cause mortality. CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. Patients with an ischaemic or non-ischaemic aetiology (n=529) on CMR were followed prospectively. All-cause mortality was 11% over a median follow up of 4.9 years, with no significant difference between sexes (11% versus 11% p=0.732). Women were more likely to have an ischaemic aetiology on CMR (40% v 31%, p=0.037). Age group (HR 1.48, p=0.002), log peak troponin (HR 0.78, p=0.033) and LVEF (HR 0.98, p=0.032) were independent predictors of mortality. Men aged &gt;60 years with a non-ischaemic aetiology on their CMR were at higher risk of death than women &gt;60 years (p=0.003).

Conclusions

There is no difference in all-cause mortality between sexes in patients presenting with ACS and non-obstructive coronary arteries but increasing age is an important predictor of mortality in both sexes.

Funding Acknowledgement

Type of funding sources: None. Sex differences in CMR diagnosisSex, age and mortality

Multifunctional Thio-Stabilized Gold Nanoparticles for Near-Infrared Fluorescence Detection and Imaging of Activated Caspase-3

Background

Gold nanoparticles (AuNPs) are commonly used in nanomedicine because of their unique spectral properties, chemical and biological stability, and ability to quench the fluorescence of organic dyes attached to their surfaces. However, the utility of spherical AuNPs for activatable fluorescence sensing of molecular processes have been confined to resonance-matched fluorophores in the 500 nm to 600 nm spectral range to maximize dye fluorescence quenching efficiency. Expanding the repertoire of fluorophore systems into the NIR fluorescence regimen with emission >800 nm will facilitate the analysis of multiple biological events with high detection sensitivity.

Objective

The primary goal of this study is to determine if spherical AuNP-induced radiative rate suppression of non-resonant near-infrared (NIR) fluorescent probes can serve as a versatile nanoconstruct for highly sensitive detection and imaging of activated caspase-3 in aqueous media and cancer cells. This required the development of activatable NIR fluorescence sensors of caspase-3 designed to overcome the nonspecific degradation and release of the surface coatings in aqueous media.

Method

We harnessed the fluorescence-quenching properties and multivalency of spherical AuNPs to develop AuNP-templated activatable NIR fluorescent probes to detect activated caspase-3, an intracellular reporter of early cell death. Freshly AuNPs were coated with a multifunctional NIR fluorescent dye-labeled peptide (LS422) consisting of an RGD peptide sequence that targets α_vβ₃-integrin protein (α_vβ₃) on the surface of cancer cells to mediate the uptake and internalization of the sensors in tumor cells; a DEVD peptide sequence for reporting the induction of cell death through caspase-3 mediated NIR fluorescence enhancement; and a multidentate hexacysteine sequence for enhancing self-assembly and stabilizing the multifunctional construct on AuNPs. The integrin binding affinity of LS422 and caspase-3 kinetics were determined by a radioligand competitive binding and fluorogenic peptide assays, respectively. Detection of intracellular caspase-3, cell viability, and the internalization of LS422 in cancer cells were determined by confocal NIR fluorescence spectroscopy and microscopy.

Results

Narrow size AuNPs (13 nm) were prepared and characterized by transmission electron microscopy and dynamic light scattering. When assembled on the AuNPs, the binding constant of LS422 for α_vβ₃ improved 11-fold from 13.2 nM to 1.2 nM. Whereas the catalytic turnover of caspase-3 by LS422-AuNPs was similar to the reference fluorogenic peptide, the binding affinity for the enzyme increased by a factor of 2. Unlike the α_vβ₃ positive, but caspase-3 negative breast cancer MCF-7 cells, treatment of the α_vβ₃ and caspase-3 positive lung cancer A549 cells with Paclitaxel showed significant fluorescence enhancement within 30 minutes, which correlated with caspase-3 specific activation of LS422-AuNPs fluorescence. Incorporation of a 3.5 mW NIR laser source into our spectrofluorometer increased the detection sensitivity by an order of magnitude (limit of detection ~0.1 nM of cypate) and significantly decreased the signal noise relative to a xenon lamp. This gain in sensitivity enabled the detection of substrate hydrolysis at a broad range of inhibitor concentrations without photobleaching the cypate dye.

Conclusion

The multifunctional AuNPs demonstrate the use of a non-resonant quenching strategy to design activatable NIR fluorescence molecular probes. The nanoconstruct offers a selective reporting method for detecting activated caspase-3, imaging of cell viability, identifying dying cells, and visualizing the functional status of intracellular enzymes. Performing these tasks with NIR fluorescent probes creates an opportunity to translate the in vitro and cellular analysis of enzymes into in vivo interrogation of their functional status using deep tissue penetrating NIR fluorescence analytical methods.

[Analysis of the short-and medium-term curative effect of TIPS approach combined with AngioJet thrombus aspiration technology treatment in acute portal vein thrombosis]

Objective: To evaluate the short- and medium-term clinical efficacy of TIPS approach combined with AngioJet thrombus aspiration technology treatment in acute portal vein thrombosis. Methods: 63 cases with acute portal vein thrombosis treated in our center from May 2017 to July 2019 were studied retrospectively, including 49 males and 14 females, aged 35-61 (46 ± 5) years. TIPS approach (with/without) combined with Angiojet thrombus aspiration and gastroesophageal varices embolization was performed simultaneously according to the patient's condition. Regular follow-up for 3-33 (22 ± 3) months after surgery was used to observe the curative effect. Results: The technical success rate was 100%. Portal vein and superior mesenteric vein blood flow were returned to normal after the operation. Two cases of biliary tract injury were untreated. Simultaneously, two cases of intrahepatic arteriovenous fistula were treated with superselective arterial embolization. During the follow-up period, 47 cases (74.61%) had complete portal vein recanalization, 13 cases (20.63%) had partial recanalization, 3 cases (4.76%) had complete portal cavernoma, 7 cases (11.11%) had symptomatic hepatic encephalopathy, 1 case had received artificial liver treatment (1.59%), 1 case had peptic ulcer (11.11%), 6 cases (9.52%) had lost to follow-up, and there was no portal hypertension-related bleeding or death. Conclusion: TIPS approach combined with AngioJet thrombus aspiration technology is safe, effective and feasible in the treatment of acute portal vein thrombosis, and the short- and medium-term clinical effects are satisfactory.

Ligand-induced native G-quadruplex stabilization impairs transcription initiation

G-quadruplexes (G4s) are noncanonical DNA secondary structures formed through the self-association of guanines, and G4s are distributed widely across the genome. G4 participates in multiple biological processes including gene transcription, and G4-targeted ligands serve as potential therapeutic agents for DNA-targeted therapies. However, genome-wide studies of the exact roles of G4s in transcriptional regulation are still lacking. Here, we establish a sensitive G4-CUT&Tag method for genome-wide profiling of native G4s with high resolution and specificity. We find that native G4 signals are cell type–specific and are associated with transcriptional regulatory elements carrying active epigenetic modifications. Drug-induced promoter-proximal RNA polymerase II pausing promotes nearby G4 formation. In contrast, G4 stabilization by G4-targeted ligands globally reduces RNA polymerase II occupancy at gene promoters as well as nascent RNA synthesis. Moreover, ligand-induced G4 stabilization modulates chromatin states and impedes transcription initiation via inhibition of general transcription factors loading to promoters. Together, our study reveals a reciprocal genome-wide regulation between native G4 dynamics and gene transcription, which will deepen our understanding of G4 biology toward therapeutically targeting G4s in human diseases.

The role of peak troponin in patients with a working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA)

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Rosetrees Trust James Tudor Foundation

Background

6-10% of patients who present with an acute coronary syndrome have a myocardial infarction with non-obstructive coronary arteries (MINOCA). Troponin T predicts infarct size and outcomes in patients with ST-elevation myocardial infarction. The value of peak troponin T in patients with a working diagnosis of MINOCA is not well understood.

Purpose

The aim of this study is to investigate the diagnostic and prognostic role of troponin in patients with MINOCA. 

Methods

Consecutive patients with a working diagnosis of MINOCA (n = 719) from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. The primary endpoint was all-cause mortality.

Results

Peak troponin T ≥211 ng/L and time to CMR of ≤17 days have a positive predictive value of 94% for being able to make a diagnosis on CMR. If the scan was performed in ≤17 days the diagnostic yield was still 75% even in the lowest troponin decile, but this was 59% if performed after 17 days. Each increase in troponin decile increases the mean diagnostic yield of the CMR by 3.7% (p &lt; 0.001, 95% CI 3.4 – 3.9; R2 0.84; Figure 1). There is no overall difference in median troponin in patients who died and those who survived (229 ng/l v. 424 ng/l; p = 0.157), however mortality is significantly lower in the highest two troponin quartiles (11.9% versus 6.9%; p = 0.009, figure 2). 

Conclusions

Peak troponin T and time to CMR can be used by cardiologists to determine the likelihood of making a diagnosis using CMR. A higher troponin quartile is associated with lower mortality.

Implementation of Rapid CMR Protocol in the COVID-19 era: improving scanning efficiency and increasing scanning capacity

Funding Acknowledgements

Type of funding sources: None.

Background

During the COVID-19 pandemic, many non-urgent elective cardiac MRI (CMR) appointments were cancelled to minimise the risk of infection to patients coming to hospital. At the time of the first lockdown, our scanning schedule allowed on average 228 scans/month. Non-urgent elective studies were cancelled from April-June 2020, resulting in 684 scans added to the waiting list.

Upon reactivation of our clinical CMR service, we developed a service quality improvement initiative consisting of using a ‘Rapid CMR’ protocol to reduce scanning time without compromising the test’s diagnostic accuracy, increase our scanning capacity and improve efficiency in reducing the backlog of requests.

Purpose

To  demonstrate the increased scanning capacity generated by the adoption of the "Rapid CMR" protocol.

Methods

The Rapid CMR protocol was implemented in November 2020 to all scans requiring cines, late gadolinium enhancement ± adenosine stress (non-stress and stress studies). The protocol was modelled on prior published experiences[1,2]. Patients who underwent these scans with additional imaging (e.g. T2-STIR imaging) were excluded. Data was collected from Nov 2020 to Jan 2021 and compared with the same time period the previous year when the standard protocol was used (cf. Image 1). Data collected included scan duration (time from first to last image), whether the Rapid CMR studies maintained diagnostic quality (yes/no), and the did-not-attend (DNA) rate.

Results

With the Rapid CMR protocol 254 patients were scanned (114 non-stress, 140 stress), compared with 286 patients scanned with standard protocol in November 2019 to January 2020 (155 non-stress, 131 stress).

Median scanning time in minutes for non-stress was 29 (IQR 25-34; Rapid) vs 37 (IQR 33-41; standard); (p < 0.001). For stress studies the median scanning time in minutes was 32 (IQR 28-36; Rapid) vs 41 (IQR 29-45;  standard; (p < 0.001). The rate of suboptimal imaging due to patient factors (such as breathing or arrhythmia) was similar for each protocol (14.4% Rapid, 20.2% standard; p = 0.04). All Rapid studies were of diagnostic quality (Table 1). Saving c.8 minutes per scan led to an improved scanning time and schedule capacity of 21%. Fewer patients were scanned with the Rapid protocol due to pandemic related issues: patient reluctance to accept appointments (unfilled slots), cleaning measures between patients (on average ∼5 mins per slot reducing overall capacity), and a higher DNA rate: 15.3% (Rapid) vs 6.5% (standard); p < 0.001.

Conclusion

The Rapid CMR protocol resulted in a statistically significant reduction in scanning time (-8 min for both stress and non-stress CMRs) increasing our schedule capacity and improving efficiency by 21%, whilst maintaining diagnostic quality. The implementation of the Rapid CMR protocol is a feasible and effective strategy to tackle the backlog of CMR clinical request accumulated during the pandemic.

Sex and age differences in patients with a working diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA): presentation and outcome

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Rosetrees Trust James Tudor Foundation

Background Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an increasingly recognised working diagnosis. Sex and age differences in MINOCA are not well understood.

Purpose  This study aims to evaluate the impact of sex and age in patients with MINOCA due to ischaemic and non-ischaemic causes on clinical presentation and outcome.

Methods and Results Consecutive patients with a working diagnosis of MINOCA (n = 719) from a single tertiary centre who underwent comprehensive cardiovascular magnetic resonance (CMR) imaging with late gadolinium enhancement (LGE) were followed prospectively. The primary endpoint was all-cause mortality.  CMR was performed at a median time of 30 days after presentation and identified a diagnosis in 74% of patients. Men were more likely to have a non-ischaemic cause on CMR (55% v. 41%, p &lt; 0.001) and less likely to have a normal/non-specific scan (21% v. 32%, p = 0.001, figure 1).  All-cause mortality was 9.5% over a median follow up of 4.9 years, with no significant difference between sexes (8.7% versus 10.1% p = 0.456).  Age group (HR 1.61, p &lt; 0.001) and LVEF (HR 0.98, p = 0.020) were independent predictors of mortality. Men aged &gt;60 years with a non-ischaemic aetiology on their CMR were at higher risk of death than women with non-ischaemic causes &gt;60 years (p = 0.003, figure 2).

Conclusions There is no difference in all-cause mortality between sexes in MINOCA but increasing age is the most important predictor of mortality in both sexes.

Propagation of Gaussian Schell-model beams in modulated graded-index media

The evolution of partially coherent beams in longitudinally modulated graded-index media is studied. The special cases of Gaussian Schell-model beams and parametric modulation, when the modulation period is half the fiber self-imaging period, are examined in detail. We show that the widths of the intensity and coherence of Gaussian Schell-model beams undergo amplification in parametrically modulated parabolic graded-index media. The process is an analog of quantum mechanical parametric amplification and generation of squeezed states. Our work may find application in spatial and temporal imaging of partially coherent beams in fiber-based imaging systems.

POS0678 DOES SILDENAFIL IMPROVE ENDOTHELIAL DYSFUNCTION IN RHEUMATOID ARTHRITIS? – A PILOT CLINICAL TRIAL

Background:

Rheumatoid arthritis (RA) is independently associated with an increased risk of cardiovascular disease (CVD). One of the early stages of atherosclerosis is endothelial dysfunction, which is increased in RA. Using drugs to target endothelial dysfunction is a promising novel strategy for CVD prevention in RA. Sildenafil has been shown to improve endothelial function in diabetics, who have similar increased CVD risk. Our hypothesis was that sildenafil use may be a novel primary CVD prevention strategy in RA.

Objectives:

To determine if sildenafil use in RA patients improves endothelial dysfunction (as measured by brachial artery flow-mediated dilation [FMD] and peripheral arterial tone [PAT]), as well as serum inflammatory and atherosclerosis biomarkers.

Methods:

This NIH-funded study was a phase II, randomized double-blind placebo-controlled crossover efficacy trial of 25 RA patients, with no known history of CVD, but at least one traditional CVD risk factor. Patients were randomized 1:1 to receive either sildenafil or placebo for 3 months, then after a 2-week washout, crossed over to each respective group for an additional 3 months. Vascular studies (FMD and PAT) and serum atherosclerosis biomarkers (e-Selectin, ICAM-1, VCAM-1) were performed at baseline, 3 months pre- and post-washout, and 6 months. Adverse events were collected. Given the cross-over design, analyses included a random effects model for within-subject comparisons of sildenafil versus placebo periods, adjusting for the baseline (FMD or EndoPAT) within that period and a term for treatment order. All tests were 2-sided with α=0.05.

Results:

A total of 233 subjects were assessed for eligibility, with 25 subjects being randomized after written informed consent. A total of 13 subjects were randomized to placebo first, and 12 to sildenafil first. Baseline characteristics were similar between those randomized to Placebo vs. Sildenafil first. Mean age was 62.0+/-10.9 years; 84% were female; and 92% were white. A total of 6 adverse events experienced in 3 subjects occurred. The primary endpoint (increase in %FMD in Sildenafil period vs. Placebo period) was not significant (p=0.19). However, note the study was powered at 80% to detect an effect size of 0.37 for change in %FMD or biomarker with a sample size of 60, not 25. However, sildenafil use was associated with a significant increase (improvement) by 0.200 units of PAT ratio (p=0.003) compared with placebo, adjusted by treatment order and baseline PAT ratio (within the given treatment period). Exploratory linear mixed models comparing e-Selectin, ICAM-1, and VCAM-1 between Sildenafil vs. Placebo periods, adjusted for treatment order and the baseline biomarker level, did not show any significant differences except for ICAM-1 (55.3 units higher in Sildenafil vs. Placebo periods, p=0.011).

Conclusion:

In this pilot trial of 25 RA subjects, sildenafil use was associated with a significant increase (improvement) in endothelial function as measured by PAT. However, there was no significant difference in FMD. The study is limited due to the small sample size, which was impacted by slow recruitment as well as the COVID-19 pandemic. Future larger studies are required to assess whether other PDE5 inhibitors may improve endothelial dysfunction in RA and other autoimmune disease patients at high risk of CVD.

References:

[1]Maradit-Kremers H, Crowson CS, Nicola PJ, et al. Increased unrecognized coronary heart disease and sudden deaths in rheumatoid arthritis: a population-based cohort study. Arthritis Rheum 2005;52:402-11.

[2]Peters MJ, van Halm VP, Voskuyl AE, et al. Does rheumatoid arthritis equal diabetes mellitus as an independent risk factor for cardiovascular disease? A prospective study. Arthritis Rheum 2009;61:1571-9.

[3]Deyoung L, Chung E, Kovac JR, et al. Daily use of sildenafil improves endothelial function in men with type 2 diabetes. J Andrology 2012;33:176-80.

Disclosure of Interests:

None declared

Application of the current HFA-ESC consensus guidelines on diagnosis of heart failure with preserved ejection fraction to a population referred for echocardiography

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

The recent Heart Failure Association (HFA) of the European Society of Cardiology (ESC) consensus guidelines on diagnosis of heart failure with preserved ejection fraction (HFpEF) have developed a simple diagnostic algorithm for clinical use.

PURPOSE

To assess whether echocardiogram (echo) parameters needed to assess diastolic function are routinely collected in patients referred for assessment of heart failure symptoms.

METHODS

Retrospective analysis of echo referrals in January 2020 were assessed for parameters of diastolic function as per step 2 of the HF-PEFF diagnostic algorithm.  Echo images and clinical reports were reviewed. Electronic records were utilised to obtain clinical history, blood results (NT-proBNP) and demographic data.

RESULTS

1330 patients underwent an echo in our department during January 2020. 83 patients were referred with symptoms of heart failure without prior history of cardiac disease; 20 patients found to have impaired left ventricular (LV) function were excluded from analysis.

Of the 63 patients with possible HFpEF, HF-PEFF score was low in 18, intermediate in 33 and high in 12. Median age was 68 years (range 32 to 97 years); 25% had a BMI &gt;30. There was a high prevalence of hypertension (52%), diabetes (19%) and atrial fibrillation (40%) (cf. Table 1). Body surface area (BSA) was documented in 65% of echo reports. Most echo parameters were recorded with the exception of global longitudinal strain (GLS) and indexed LV mass (cf. image 1). NT-proBNP was recorded in only 20 patients (31.7%). 12 patients with an intermediate HF-PEFF score could have been re-categorised to a high score depending on GLS and NT-proBNP (which were not recorded).

CONCLUSION

More than three quarters of echoes acquired in our department obtained the relevant parameters to assess diastolic function. The addition of BSA, and inclusion of NT-proBNP, and GLS would have been additive to a third of ‘intermediate’ patients to determine definite HFpEF. Our study demonstrates that the current HFA-ESC diagnostic algorithm and HF-PEFF scoring system are easy to use, highly relevant and applicable to current clinical practice.

Age &gt;70 years 29 (46.0%) Obesity (BMI &gt;30) 16 (25.4%) Diabetes 12 (19%) Hypertension 33 (52.4%) Atrial Fibrillation 25 (39.7%) ECG abnormalities 18 (28.5%) Table 1. Prevalence of Clinical Risk Factors Abstract Figure. Image 1. HFPEFF score & echo parameters

Genomic profiling of native R loops with a DNA-RNA hybrid recognition sensor

An R loop is a unique triple-stranded structure that participates in multiple key biological processes and is relevant to human diseases. Accurate and comprehensive R loop profiling is a prerequisite for R loops studies. However, current R loop mapping methods generate large discrepancies, therefore an independent method is in urgent need. Here, we establish an independent R loop CUT&Tag (Tn5-based cleavage under targets and tagmentation) method by combining CUT&Tag and GST-His₆-2×HBD (glutathione S-transferase-hexahistidine-2× hybrid-binding domain), an artificial DNA-RNA hybrid sensor that specifically recognizes the DNA-RNA hybrids. We demonstrate that the R loop CUT&Tag is sensitive, reproducible, and convenient for native R loop mapping with high resolution, and find that the capture strategies, instead of the specificity of sensors, largely contribute to the disparities among different methods. Together, we provide an independent strategy for genomic profiling of native R loops and help resolve discrepancies among multiple R loop mapping methods.

Multiple Convolutional Recurrent Neural Networks for Fault Identification and Performance Degradation Evaluation of High-Speed Train Bogie

As an important part of high-speed train (HST), the mechanical performance of bogies imposes a direct impact on the safety and reliability of HST. It is a fact that, regardless of the potential mechanical performance degradation status, most existing fault diagnosis methods focus only on the identification of bogie fault types. However, for application scenarios such as auxiliary maintenance, identifying the performance degradation of bogie is critical in determining a particular maintenance strategy. In this article, by considering the intrinsic link between fault type and performance degradation of bogie, a novel multiple convolutional recurrent neural network (M-CRNN) that consists of two CRNN frameworks is proposed for simultaneous diagnosis of fault type and performance degradation state. Specifically, the CRNN framework 1 is designed to detect the fault types of the bogie. Meanwhile, CRNN framework 2, which is formed by CRNN Framework 1 and an RNN module, is adopted to further extract the features of fault performance degradation. It is worth highlighting that M-CRNN extends the structure of traditional neural networks and makes full use of the temporal correlation of performance degradation and model fault types. The effectiveness of the proposed M-CRNN algorithm is tested via the HST model CRH380A at different running speeds, including 160, 200, and 220 km/h. The overall accuracy of M-CRNN, i.e., the product of the accuracies for identifying the fault types and evaluating the fault performance degradation, is beyond 94.6% in all cases. This clearly demonstrates the potential applicability of the proposed method for multiple fault diagnosis tasks of HST bogie system.

Reduced orbitofrontal grey matter volume in myocardial infarction with non-obstructive coronary arteries (MINOCA)

Background

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is seen in 6–10% of patients presenting acutely with suspected myocardial infarction. Cardiac magnetic resonance imaging (CMR) can identify an underlying cause in ∼80% of patients. These patients are more likely to have a history of mental health illness or an emotional or stressful precipitant.

Grey matter volume can be quantified in various anatomical regions of the brain and has been shown to be altered in common mental health conditions such as anxiety, stress and depression.

This is the first prospective study investigating the acute structural brain, cardiac and psychological changes using MRI in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) within 14 days of presentation compared to STEMI control patients.

Methods

Patients meeting the 2017 ESC definition of MINOCA were prospectively recruited with STEMI control patients from February to December 2019. All participants underwent brain and comprehensive cardiac MRI, bloods and baseline psychological evaluation. We used voxel-based morphometry (VBM) to quantify grey matter volume and changes were compared between groups.

Results

54 patients were included in this interim analysis (39 MINOCA, 15 STEMI controls). Demographics were largely similar but MINOCA patients were more likely to have a history of self-reported mental health disease (36% v 7%, p 0.03) and had significantly higher baseline anxiety (8.4 v 5.3, p 0.01) scores on the HADS questionnaire. We found that control patients have significantly greater grey matter volume in the orbitofrontal cortex (OFC) compared to MINOCA patients (pFWE-corr 0.002). The orbitofrontal cortex is involved in emotional processing and implicated in anxiety and depression. However, there was no association between grey matter volume in any brain region and anxiety, depression or perceived stress scale scores.

Conclusion

Patients with MINOCA are more likely to have a history of mental health disease and have higher anxiety scores at presentation than STEMI controls. They have less grey matter volume in the orbitofrontal cortex compared to STEMI controls.

Reduced Grey Matter Volume in the OFC

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Rosetrees Trust; James Tudor Foundation

MicroRNA-29 targets FGF2 and inhibits the proliferation, migration and invasion of nasopharyngeal carcinoma cells via PI3K/AKT signaling pathway

OBJECTIVE

Studies have indicated that miRNAs may prove essential therapeutic targets for the treatment of cancer. The study was designed to investigate the role and therapeutic potential of miR-29 in nasopharyngeal cancer.

MATERIALS AND METHODS

The quantitative Real-time polymerase chain reaction (qRT-PCR) was used for expression analysis. WST-1 assay was used for cell viability assessment. The 4',6-diamidino-2-phenylindole (DAPI) staining and electron microscopic analysis was used for the detection of apoptosis and autophagy, respectively. Transwell assays were used for cell migration and invasion assay.

RESULTS

It was found that miR-29 is significantly downregulated in nasopharyngeal cancer cell lines. Overexpression of miR-29 causes decrease in the viability of CNE2 nasopharyngeal cancer cells via induction of apoptosis and autophagy. Bioinformatics analysis indicated FGF2 to be the target of miR-29 in CNE2 cells, which was also confirmed by luciferase reporter assay. The qRT-PCR results showed fibroblast growth factor 2 (FGF2) to be significantly upregulated in the nasopharyngeal cancer cell lines. However, miR-29 overexpression in CNE2 cells resulted in post-transcriptional suppression of FGF2 expression. Nonetheless, silencing of FGF2 also caused inhibition of CNE2 cell proliferation via induction of apoptosis and autophagy. Overexpression of FGF2 could reverse the effects of miR-29 overexpression on the proliferation of CNE2 cells. Moreover, overexpression of miR-29 causes significant decline in the phosphorylation of PI3K and AKT expression cells and inhibits their migration and invasion of the CNE2 cells. Finally, miR-29 overexpression could also suppress the subcutaneous xenografted tumor growth.

CONCLUSIONS

The findings of the present study indicate the therapeutic implications of miR-29 in nasopharyngeal carcinoma.

FRI0570 IDENTIFICATION OF OSTEOPONTIN/SECRETED PHOSPHOPROTEIN 1 AS A BIOMARKER FOR PSORIATIC ARTHRITIS

Background:

Early diagnosis of psoriatic arthritis (PsA) can be facilitated by appropriate referral of psoriasis patients to rheumatologists. Soluble biomarkers for PsA may help screen psoriasis patients for PsA.

Objectives:

To identify novel biomarkers for PsA by investigating serum levels of candidate biomarkers identified through proteomic analysis of synovial fluid (SF) and skin biopsies and literature review.

Methods:

We first (discovery phase) identified markers using: i) proteomic analysis of SF1, ii) proteomic analysis of skin biopsies2, and iii) literature review. In verification phase 1, we measured serum levels of the selected potential protein markers, using commercially available ELISA kits, to identify differentially expressed markers in healthy controls and patients with PsA (≥3 swollen joints, not treated with biologics) and psoriasis without PsA (PsC; matched with PsA patients on age, sex and psoriasis duration) (100 subjects each group). In verification phase 2, using less strict criteria (no restriction on pharmacotherapy or disease activity) and larger sample size, we confirmed the association with PsA of markers identified in phase 1 using samples from 200 patients each with PsA and PsC. Statistical methods used included descriptive statistics, t-tests and logistic regression.

Results:

The discovery phase identified the following 31 markers for testing in verification phase 1- hsCRP, MMP3, CD5L, M2BP, MPO, ITGB5, DKK1, FGF23, IL-6, IL-1β, leptin, osteocalcin, OPG, OPN, SOST, TNFα, adiponectin, periostin, RANKL, YKL40, KLK6, KLK8, CS846, C2C, CPII, TNFSF14, COMP, ALP, CXCL10, S100A8/A9 and DEFA. The following 21 markers remained differentially upregulated in PsA after testing in verification phase 1- hsCRP, MMP-3, M2BP, ITGB5, leptin, OPG, OPN, SOST,TNFα, periostin, RANKL, YKL40, KLK8, C2C, CPII, TNFSF14, COMP, ALP, CXCL10, S100A8/A9 and DEFA. Univariate logistic regression analyses adjusted for age, sex, and disease duration confirmed the association between hsCRP, OPN, S100A8/A9, OPG and the ratio CPII/C2C in verification phase 2. Multivariate logistic regression demonstrated that hsCRP and OPN (both p<0.001) are independently associated with PsA.

Conclusion:

OPN, a cytokine involved in enhancing production of IFNγ and IL-12, reducing production of IL-10 and promoting attachment of osteoclasts to mineralized bone matrix, is a potential biomarker of PsA.

References:

[1] Cretu D, Prassas I, Saraon P, Batruch I, Gandhi R, Diamandis EP, Chandran V. Identification of psoriatic arthritis mediators in synovial fluid by quantitative mass spectrometry. Clin Proteomics. 2014 Jul 1;11(1):27.

[2] Cretu D, Liang K, Saraon P, Batruch I, Diamandis EP, Chandran V. Quantitative tandem mass-spectrometry of skin tissue reveals putative psoriatic arthritis biomarkers. Clin Proteomics. 2015 Jan 13;12(1):1.

Disclosure of Interests:

Fatima Abji: None declared, Rohan Machhar: None declared, Kun Liang: None declared, Justine Ye: None declared, Katerina Oikonomopoulou: None declared, Vinod Chandran Grant/research support from: Abbvie, Celgene, Consultant of: Abbvie, Amgen, Bristol-Myers Squibb, Celgene, Eli Lily, Janssen, Novartis, Pfizer, UCB, Employee of: Spouse employed by Eli Lily

Stable expression ratios of five pyroptosis-inducing cytokines in the spleen and thymus of mice showed potential immune regulation at the organ level

BACKGROUND

The immune system is one of the most complex regulatory systems in the body and is essential for the maintenance of homeostasis. Despite recent breakthroughs in immunology, the regulation of the immune system and the etiology of autoimmune diseases such as lupus remain unclear. Systemic lupus erythematosus is a systemic autoimmune disease with abnormally and inconsistently expressed pro-inflammatory cytokines. Pyroptosis is a pro-inflammatory form of programmed cell death that is associated with systemic lupus erythematosus. The thymus and spleen are important immune organs involved in systemic lupus erythematosus. Therefore, this study investigated the difference in expression of pyroptosis-inducing pro-inflammatory cytokines between the spleen and thymus in lupus model mice and in control mice, to describe immune regulation at the organ level.

OBJECTIVE

To investigate differences in the expression of pyroptosis-inducing cytokines in the spleen and thymus and to explore immune regulatory networks at the organ level.

METHODS

Two groups of lupus mice and two groups of control mice were utilized for this study. Using the thymus and spleen of experimental animals, mRNA expression levels of five pyroptosis-inducing cytokines (interleukin 1β, interleukin 18, NLRP3, caspase-1 and TNF-α) were determined via quantitative polymerase chain reaction. In addition, tissue distribution of these cytokines was investigated via immunohistochemistry.

RESULTS

All five pyroptosis-inducing inflammatory cytokines showed higher expression in the spleen than in the thymus (p < 0.05). Moreover, the spleen/thymus expression ratios of all five pyroptosis-inducing cytokines were not statistically different between the four experimental groups. Expression of all five cytokines exhibited a stable ratio (spleen/thymus ratios). This distinctive stable spleen/thymus ratio was consistent in all four experimental groups. The stable spleen/thymus ratios of the five inflammatory cytokines were as follows: interleukin 1β (2.02 ± 0.9), interleukin 18 (2.07 ± 1.06), caspase-1 (1.93 ± 0.66), NLRP3 (3.14 ± 1.61) and TNF-α (3.16 ± 1.36). Immunohistochemical analysis showed the cytokines were mainly expressed in the red pulp region of the spleen and the medullary region of the thymus, where immune-activated cells aggregated.

CONCLUSION

The stable spleen/thymus expression ratios of pyroptosis-inducing cytokines indicated that immune organs exhibit strictly regulated functions to maintain immune homeostasis and adapt to the environment.

Effects of a nutrient-dense formula compared with a post-discharge formula on post-discharge growth of preterm very low birth weight infants with extrauterine growth retardation: a multicentre randomised study in China

BACKGROUND

Post-discharge optimal growth and nutritional intake have beneficial effects for neurodevelopment in preterm very low birth weight infants (VLBWIs) with extrauterine growth retardation (EUGR). The present study aimed to compare the effects of a nutrient-dense formula (NDF) to a post-discharge formula (PDF) on post-discharge growth of preterm VLBWIs with EUGR.

METHODS

Forty-eight preterm VLBWIs with EUGR at discharge were randomised to receive NDF (100 kcal per 100 mL; 2.6 g protein per 100 mL) or PDF (74 kcal per 100 mL; 1.95 g protein per 100 mL) for 1-6 months until body weight reached the 50th percentile on growth charts with corrected age. Volume, nutrient intake, anthropometry and biochemistry data were collected.

RESULTS

Volume intake was lower in the NDF group than the PDF group during the first 2 months of feeding (P = 0.039 and 0.018, respectively).There were no significant differences in volume intake during months 2-6 of feeding. Energy, protein, carbohydrate and fat intake were higher in the NDF group during months 1-6 of feeding. There were no significant differences in weight, length, and head circumference Z-scores during months 1-6 between the two groups. The △length Z-score from discharge to month 6 was significantly higher in the NDF group than the PDF group (P = 0.043). No differences existed between the two groups with respect to biochemistry.

CONCLUSIONS

After discharge, preterm VLBWIs with EUGR fed a NDF gain anthropometric parameter Z-scores similar to those for a PDF within 6 months of follow-up. A NDF leading to gain in length requires further follow-up.

Differential tissue expression of erythroblast macrophage protein in a MRL/lpr mouse model of lupus

OBJECTIVE

The objective of this study was to observe the expression features of erythroblast macrophage protein (EMP) between the tissues of MRL/lpr mice, a mouse model of systemic lupus erythematosus (SLE), and control mice.

METHODS

We examined the serum ANA in both mice groups through indirect immunofluorescence (IIF). Expression features of EMP in bone marrow, liver, renal, spleen, brain, and lung tissues of the MRL/lpr mice and control mice groups were followed using quantitative real-time polymerase chain reaction (Q-PCR). Meanwhile, the expression of EMP was located through immunohistochemical (IHC) studies and the expressive cell identified through double immunofluorescent labeling.

RESULTS

IIF showed that lupus mice have strong positive fluorescence, but no significant fluorescence was observed in control mice. Q-PCR detection revealed that EMP was expressed in the marrow, liver, renal, spleen, lung, and brain tissues of lupus mice. The highest levels were observed in the bone marrow, but there was no statistical difference between these tissues. EMP mRNA expression in the liver (t = 2.747, p = 0.01) and bone marrow (t = 3.853, p = 0.008) of lupus mice was significantly higher than in the control mice. However, no differences in EMP mRNA expression were observed in the renal, spleen, lung, and brain tissues between the lupus and control mice (p > 0.05). In addition, the IHC results showed that EMP protein is ubiquitously expressed in all of the tissues of the lupus and control mice. The positive expression rate in the bone marrow and liver tissues of the lupus mice was higher than in the control mice, but without an obvious difference in the other tissues. The double IF staining method shows that EMP protein was expressed in macrophages in the tissues of the lupus mice and the control mice.

CONCLUSIONS

Our data showed that EMP is ubiquitously expressed in macrophages at all of the tissues of the lupus and control mice. However, the expression of EMP in bone marrow and liver tissues of lupus mice was higher than in the control mice, which indicates that EMP may be important in the development of SLE.