Permissive epigenomes endow reprogramming competence to transcriptional regulators

Identifying molecular and cellular processes that regulate reprogramming competence of transcription factors broadens our understanding of reprogramming mechanisms. In the present study, by a chemical screen targeting major epigenetic pathways in human reprogramming, we discovered that inhibiting specific epigenetic roadblocks including disruptor of telomeric silencing 1-like (DOT1L)-mediated H3K79/K27 methylation, but also other epigenetic pathways, catalyzed by lysine-specific histone demethylase 1A, DNA methyltransferases and histone deacetylases, allows induced pluripotent stem cell generation with almost all OCT factors. We found that simultaneous inhibition of these pathways not only dramatically enhances reprogramming competence of most OCT factors, but in fact enables dismantling of species-dependent reprogramming competence of OCT6, NR5A1, NR5A2, TET1 and GATA3. Harnessing these induced permissive epigenetic states, we performed an additional screen with 98 candidate genes. Thereby, we identified 25 transcriptional regulators (OTX2, SIX3, and so on) that can functionally replace OCT4 in inducing pluripotency. Our findings provide a conceptual framework for understanding how transcription factors elicit reprogramming in dependency of the donor cell epigenome that differs across species.

A novel xeno-organoid approach: exploring the crosstalk between human iPSC-derived PGC-like and rat testicular cells

Specification of germ cell-like cells from induced pluripotent stem cells has become a clinically relevant tool for research. Research on initial embryonic processes is often limited by the access to foetal tissue, and in humans, the molecular events resulting in primordial germ cell (PGC) specification and sex determination remain to be elucidated. A deeper understanding of the underlying processes is crucial to describe pathomechanisms leading to impaired reproductive function. Several protocols have been established for the specification of human pluripotent stem cell towards early PGC-like cells (PGCLC), currently representing the best model to mimic early human germline developmental processes in vitro. Further sex determination towards the male lineage depends on somatic gonadal cells providing the necessary molecular cues. By establishing a culture system characterized by the re-organization of somatic cells from postnatal rat testes into cord-like structures and optimizing efficient PGCLC specification protocols, we facilitated the co-culture of human germ cell-like cells within a surrogate testicular microenvironment. Specified conditions allowed the survival of rat somatic testicular and human PGCLCs for 14 days. Human cells maintained the characteristic expression of octamer-binding transcription factor 4, SRY-box transcription factor 17, and transcription factor AP-2 gamma and were recovered from the xeno-organoids by cell sorting. This novel xeno-organoid approach will allow the in vitro exploration of early sex determination of human PGCLCs.

Anterior skull base olfactory tumours, which is what? A case report and review

Intracranial schwannomas not originating from cranial nerves are rare. In this paper, we report a case of a 50-year-old male who presented with worsening headaches, diplopia and nausea over two years. Radiological imaging revealed a large tumour arising from the olfactory groove region with a preoperative diagnosis of olfactory groove meningioma (OGM). Intraoperatively, the tumour originated from the region of the attachment of the falx to the crista galli. The patient recovered without complication and histopathology reported an unexpected diagnosis of WHO Grade 1 schwannoma. However, as olfactory groove schwannomas (OGSs) cannot be distinguished from olfactory ensheathing cell tumours (OECTs), it is possible that the tumour could have been either an OGS or an OECT. Distinguishing between OGSs, OECTs and OGMs preoperatively is difficult. OGMs exhibit distinct histopathological features from OGSs/OECTs, however, OGSs and OECTs currently cannot be distinguished from each other. Here, we review the literature to discuss the differentiating features and cellular origins of these three tumours.

Generation of a human iPSC line (MPIi007-A) from a patient with Metachromatic leukodystrophy

Here we have generated a human induced pluripotent stem cells (hiPSC) line (MPIi007-A) from skin fibroblasts of a 4-year-old male Metachromatic leukodystrophy (MLD) patient with a heterozygous 1178C > G (Thr393Ser) mutation in arylsulfatase A (ARSA) gene via retroviral expression of OCT4, SOX2, KLF4 and c-MYC. The MPIi007-A iPSC line displayed typical embryonic stem cell-like morphology, carried the ARSA gene mutation, expressed several pluripotent stem cell makers, retained normal karyotype (46, XY) and were capable of forming teratomas containing three germ layers. The MPIi007-A line can be used for the characterization of MLD-associated pathomechanisms and developing new therapeutic options.

Reprogramming competence of OCT factors is determined by transactivation domains

OCT4 (also known as POU5F1) plays an essential role in reprogramming. It is the only member of the POU (Pit-Oct-Unc) family of transcription factors that can induce pluripotency despite sharing high structural similarities to all other members. Here, we discover that OCT6 (also known as POU3F1) can elicit reprogramming specifically in human cells. OCT6-based reprogramming does not alter the mesenchymal-epithelial transition but is attenuated through the delayed activation of the pluripotency network in comparison with OCT4-based reprogramming. Creating a series of reciprocal domain-swapped chimeras and mutants across all OCT factors, we clearly delineate essential elements of OCT4/OCT6-dependent reprogramming and, conversely, identify the features that prevent induction of pluripotency by other OCT factors. With this strategy, we further discover various chimeric proteins that are superior to OCT4 in reprogramming. Our findings clarify how reprogramming competences of OCT factors are conferred through their structural components.

Inhibitory effect of alpha-lipoic acid on mitochondrial dysfunction and interleukin-8 expression in interleukin-1beta-stimulated ataxia teleangiectasia fibroblasts

Ataxia telangiectasia (A-T) is an inherited neurodegenerative disease caused by mutation in the ataxia telangiectasia mutated (ATM) gene, leading to loss of function in the encoded protein ATM. Because ATM functions to reduce oxidative stress by up-regulating antioxidant enzymes, oxidative stress is a prevalent A-T phenotype and a mediator of the inflammation that drives A-T pathology. Reactive oxygen species (ROS) levels and the expression of pro-inflammatory cytokine interleukin-8 (IL-8) were higher in A-T cells than in normal cells. ROS are related to mitochondrial dysfunction and activation of nuclear factor kappa B (NF-κB) to induce IL-8 expression. Alpha-lipoic acid (α-LA), a naturally occurring thiol compound, shows an antioxidant effect in various cells. This study is aimed to determine if α-LA confers protection against NF-κB activation, IL-8 expression, and mitochondrial dysfunction in A-T cells which are exposed to the inflammatory cytokine IL-1β. A-T fibroblasts were treated with or without α-LA. The levels of intracellular and mitochondrial ROS, mRNA and protein levels of IL-8, mitochondrial membrane potential (MMP), ATP levels, and DNA binding activity of NF-κB were determined. As a result, IL-1β increased NF-κB activation, IL-8 expression, intracellular and mitochondrial ROS levels, but decreased MMP and ATP level in A-T cells. Pretreatment of A-T cells with α-LA inhibited IL-1β-induced activation of NF-κB, IL-8 expression, and mitochondrial dysfunction by reducing ROS levels. In conclusion, supplementation with α-LA may be beneficial for reducing the oxidative stress-induced mitochondrial dysfunction and IL-8 production associated with A-T.

AB1121 IMPLEMENTING HIGH VALUE CARE IN INPATIENT ANTINUCLEAR ANTIBODY TESTING

Background:

Antinuclear Antibody (ANA) testing forms the basis on which many rheumatological diseases are subsequently diagnosed. ANA testing quantifies the dilution of plasma to produce the titer and staining pattern and this can be a part of an ANA order set that reflexively cascades to sub-serology if positive. Studies have shown that a low titer ANA may potentially translate into an erroneous diagnosis: if one estimates a 1 percent prevalence of ANA associated disease in the general population then 30% of those individuals would have a false positive result of ANA detected at 1:40 titer [1]. We theorized that there is no need for several methods to coexist within a single inpatient hospital setting especially since diagnostic value of staining patterns alone is limited.

Objectives:

To compare the utility and yield of “ANA screening reflex to profile” (ARP) and “ANA reflex to titer” (ART) order sets in the inpatient setting of a community tertiary care hospital. We aim to identify the appropriateness of the ANA testing ordered including cost-effectiveness of ordering ARP over ART in order to implement the identified quality measures towards improving utilization of ANA testing.

Methods:

We identified all inpatient ANA reflex testing orders performed at Community Regional Medical Center, Fresno, California completed between 11/2018 till 07/2019. This included ART and ARP orders with 6 sub-serologies: SSA, SSB, dsDNA, Smith, Scl-70 and U1RNP. A Health Information Management report was generated which included patient’s age, gender, length of hospital stay, dates of testing ordered, principal diagnosis and type of ANA testing ordered. Descriptive statistics were computed and analyzed.

Results:

We reviewed a total of 1,012 ANA lab orders performed between 11/01/2018 until 07/30/2019 performed on 700 patients. According to the laboratory standard using Immunofluorescence Assay, an ANA titer starting from 1:40 is reported as positive. Out of the 1,012 tests, 334 tests were positive i.e. 33%. The ART order by itself contributed to 29.9% of the positive testing while ARP formed 70% of the positive testing. 56 of the 910 ARP (6%) performed had one or more sub-serology antibody positive while in 178 ARP orders (20%) only the ANA titer was positive with negative serology. The most common sub-serology antibody noted positive was dsDNA forming 54% of the positive serology results. Multiple testing was noted with 218 orders of ARP and ART being ordered on the same patient within the same week, which shows 21.5% of ANA lab orders were repetitive. Length of stay was noted to be more than 3 days for 89% of the patients who had repetitive testing, majority of those tests (99%) on the same day by the same medical provider. It cost $5.0 for an ART order that resulted negative and $5.0 for an ARP panel that resulted negative. It cost $10.0 for those patients who had both ART and ARP ordered with negative results. A positive ART result added $12.0 additional to the cost of each positive ANA profile ($67.36) when both tests were ordered together.

Conclusion:

Our study findings reflect the need for using higher yield ANA testing that has been standardized. It demonstrated that physicians ordering the testing were not familiar with the ART vs. ARP, and the laboratory orders needed to be re-structured. We removed the ART from the inpatient Electronic Medical Record i.e. Epic system so that only the ARP order remained. This would prevent repetitive testing and reduce healthcare costs through reduction by at least $12.0 per positive ANA result and may also translate into reduced length of hospital stay. We were able to add Centromere Antibody (Ab) to the ANA profile sub serologies to standardize it further as it is an important part of Scleroderma diagnosis.

References:

[1]Range of antinuclear antibodies in “healthy” individuals. AU, Tan EM, et al. Arthritis Rheum. 1997; 40(9):1601

Disclosure of Interests:

None declared

Generation of a human iPSC line (MPIi006-A) from a patient with Pelizaeus-Merzbacher disease

We established a human induced pluripotent stem cells (hiPSC) line (MPIi006-A) from fibroblasts of a 20-year-old male Pelizaeus-Merzbacher disease (PMD) patient with a hemizygous 643C>T mutation in proteolipid protein 1 (PLP1) gene using a retroviral delivery of OCT4, SOX2, KLF4 and c-MYC. The MPIi006-A iPSC line carried the mutation, displayed typical iPSC morphology, expressed pluripotent stem cell makers, exhibited normal karyotype and were capable of differentiating into cells representative of three germ layers.

P6419Machine learning in critical care: the role of diabetes and age in acute coronary syndromes

Background

Patients with diabetes and non-ST elevation acute coronary syndrome (NSTE-ACS) have an increased risk of mortality and adverse outcomes following percutaneous coronary intervention (PCI).

Purpose

We aimed to investigate the impact of early, within 24 hours PCI compared with only routine medical treatment on clinical outcomes in a large international cohort of patients with NSTE-ACS and diabetes.

Methods

We identified 1,250 patients with diabetes and NSTE-ACS from a registry-based population between October 2010 and April 2016. The primary endpoint was 30-day all-cause mortality. The secondary endpoint was the composite outcome of 30-day all-cause mortality and left ventricular dysfunction (ejection fraction <40%). We undertook analyses to explore the heterogeneity of treatment effects using meta-classification (MC) algorithms followed by propensity score matching and inverse-probability-of-treatment weighting (IPTW) from a landmark of 24 hours from hospitalization.

Results

Of 1,250 NSTE-ACS first-day survivors with diabetes (median age 67 years; 59%, men), 470 (37.6%) received early PCI and 780 routine medical treatment. The overall 30-day all-cause mortality rates were higher in the routine medical treatment than the early PCI group (6.3% vs. 2.5%). The prediction results of the MC algorithms accounted for only one interaction term that was statistically significant: age ≥65 years. After propensity-matched analysis as well as IPTW, early PCI was associated with reduced 30-day all-cause mortality in the older age (OR: 0.35; 95% CI: 0.14 to 0.92 and 0.43; 95% CI: 0.21 to 0.86, respectively), whereas younger age had no association with the primary endpoint. Similar results were also obtained for the secondary endpoint.

Conclusions

Among patients with diabetes hospitalized for NSTE-ACS, an early, within 24 hours, PCI strategy is associated with reduced odds of 30-day mortality only for patients aged 65 years or over. MC algorithms provide accurate identification of treatment effect modifiers.

CT features of extrahepatic arterioportal fistula in two cats

Two cats presented with large volume ascites and the cause was suspected to be portal hypertension. On contrast CT they both showed enhancement of the main portal vein during the arterial phase and an anomalous connection between the celiac artery and extrahepatic portal vasculature, prompting a diagnosis of extrahepatic arterioportal fistula. An extrahepatic arterioportal fistula is a connection between any artery and the portal vein outside the liver and, to our knowledge, this is the first report in cats.