Shear stress switches the association of endothelial enhancers from ETV/ETS to KLF transcription factor binding sites

Endothelial cells (ECs) lining blood vessels are exposed to mechanical forces, such as shear stress. These forces control many aspects of EC biology, including vascular tone, cell migration and proliferation. Despite a good understanding of the genes responding to shear stress, our insight into the transcriptional regulation of these genes is much more limited. Here, we set out to study alterations in the chromatin landscape of human umbilical vein endothelial cells (HUVEC) exposed to laminar shear stress. To do so, we performed ChIP-Seq for H3K27 acetylation, indicative of active enhancer elements and ATAC-Seq to mark regions of open chromatin in addition to RNA-Seq on HUVEC exposed to 6 h of laminar shear stress. Our results show a correlation of gained and lost enhancers with up and downregulated genes, respectively. DNA motif analysis revealed an over-representation of KLF transcription factor (TF) binding sites in gained enhancers, while lost enhancers contained more ETV/ETS motifs. We validated a subset of flow responsive enhancers using luciferase-based reporter constructs and CRISPR-Cas9 mediated genome editing. Lastly, we characterized the shear stress response in ECs of zebrafish embryos using RNA-Seq. Our results lay the groundwork for the exploration of shear stress responsive elements in controlling EC biology.

Abstract 112: The 3CL Protease Of SARS-CoV2 Induces Sarcomeric Degradation Through Cleavage Of The Giant Protein Obscurin

We hypothesized that the 3CL protease (3CLPro) is responsible for the sarcomere degradation observed in cardiomyocytes infected by SARS-COV2. Overexpression of 3CLPro, but not a catalytically inactive mutant, resulted in breakdown of sarcomeres characterized by intact Z-disk/thin filament subunits that has been recently reported (Perez-Bermejo, et al, 2021) in SARS-COV2 infection. To identify potential host protein targets of 3CLPro in an unbiased fashion we screened the human proteome using a cut-site scoring algorithm that we developed. Scoring, ie likelihood of 3CL protease cleavage, was based off experimental data (Chuck et al, 2010) previously published on the highly homologous (96%) 3CL protease from SARS-COV. This scoring was followed by refinement by secondary structure prediction to identify cut-sites that lie in unstructured regions that are thus thus more likely to be accessible to the protease. Using this method, we identified >1000 potential high-likelihood cut sites across the proteome. Further filtering by proteins with cardiomyocyte expression showed 5 high-likelihood sites within the giant sarcomeric protein, Obscurin (OBSCN), as well as many other structural and signaling proteins which we experimentally validated. Expression of 3CLPro in IPSC cardiomyocytes resulted in significantly reduced OBSCN staining without alterations in Z-disk, thin filament, or thick filament proteins by both western blot and immunocytochemistry. In addition, imaging showed loss of OBSCN at sites with intact Z-disk/thin filament subunits. Thus we propose that activity of 3CLPro is a significant contributor to sarcomere breakdown in SARS-COV2 infection via degradation of Obscurin.

Abstract P322: Ror2: A Novel Regulator Of Cardiomyocyte Structure And Target Of Right Ventricular Failure

Introduction: We recently identified the fetal noncanonical WNT receptor ROR2 as being re-expressed in human right ventricular failure (RVF), but the myocardial role of ROR2 remains poorly described.

Hypothesis: We assessed if ROR2 expression influences cardiomyocyte structure or contributes to RVF pathogenesis.

Methods: ROR2 gain- and loss-of-function (ROR2 GOF and ROR2 LOF ) NRVMs were generated using adenoviral-delivered ROR2 cDNA or shRNA and cultured on nanopatterned substrates. NRVM structure was assessed by confocal microscopy (minimum n=3 replicates, >30 cells/condition). NRVM gene expression was characterized by RNAseq. The impact of ROR2 on RV structure and function was assessed using AAV9-mediated cardiac ROR2 delivery, in 4-week old C57BL/6 mice (vs GFP), and echocardiography and hemodynamics (n= 8, 50% male).

Results: ROR2 GOF disrupts non-sarcomeric and sarcomeric NRVM structure, exhibiting smaller (500 vs. 711 μm 2 , p = 7.4x10 -23 ) and rounder (aspect ratio 2.1 vs. 3.1, p=1.9x10 -16 ) shape and fragmented sarcomeres (Figure). Whereas, ROR2 LOF NRVMs demonstrate a striking peripheralization of α-actinin and β-catenin. Gene-set enrichment analyses of ROR2 GOF NRVMs reveal upregulation of cytokinesis, mitosis, microtubule regulation, and insulin like growth factor receptor signaling. By 4 weeks after induction of ROR2 GOF in vivo , mice exhibit biventricular dilation and systolic dysfunction (TAPSE 0.85 vs 1.2 mm, p = 2.1x10 -5 ; right ventricular outflow dimension 2.0 vs 1.7 mm, p = 0.001, LV EDV 33.5 vs 28.6 μL, p = 0.05; LV ejection fraction 63% vs 69%, p = 0.015). RV diastolic function is reduced in ROR2 GOF (E:e’ 21.8 vs 18.6, p = 0.004 and RV EDP 2.9 vs 1.0 mmHg, p = 0.06).

Conclusions: ROR2 GOF causes biventricular dilation, systolic and diastolic dysfunction in vivo . In vitro, ROR2 GOF NRVMs exhibit an immaturity phenotype with maintenance of proliferation gene program. In contrast, ROR2 LOF NRVMs form a tight monolayer with enhanced cell-cell borders.

Cardiac endothelial cells maintain open chromatin and expression of cardiomyocyte myofibrillar genes

Endothelial cells (ECs) are widely heterogenous depending on tissue and vascular localization. Jambusaria et al. recently demonstrated that ECs in various tissues surprisingly possess mRNA signatures of their underlying parenchyma. The mechanism underlying this observation remains unexplained, and could include mRNA contamination during cell isolation, in vivo mRNA paracrine transfer from parenchymal cells to ECs, or cell-autonomous expression of these mRNAs in ECs. Here, we use a combination of bulk RNASeq, single-cell RNASeq datasets, in situ mRNA hybridization, and most importantly ATAC-Seq of FACS-isolated nuclei, to show that cardiac ECs actively express cardiomyocyte myofibril (CMF) genes and have open chromatin at CMF gene promoters. These open chromatin sites are enriched for sites targeted by cardiac transcription factors, and closed upon expansion of ECs in culture. Together, these data demonstrate unambiguously that the expression of CMF genes in ECs is cell-autonomous, and not simply a result of technical contamination or paracrine transfers of mRNAs, and indicate that local cues in the heart in vivo unexpectedly maintain fully open chromatin in ECs at genes previously thought limited to cardiomyocytes.

Noncanonical WNT Activation in Human Right Ventricular Heart Failure

Background: No medical therapies exist to treat right ventricular (RV) remodeling and RV failure (RVF), in large part because molecular pathways that are specifically activated in pathologic human RV remodeling remain poorly defined. Murine models have suggested involvement of Wnt signaling, but this has not been well-defined in human RVF.

Methods: Using a candidate gene approach, we sought to identify genes specifically expressed in human pathologic RV remodeling by assessing the expression of 28 WNT-related genes in the RVs of three groups: explanted nonfailing donors (NF, n = 29), explanted dilated and ischemic cardiomyopathy, obtained at the time of cardiac transplantation, either with preserved RV function (pRV, n = 78) or with RVF (n = 35).

Results: We identified the noncanonical WNT receptor ROR2 as transcriptionally strongly upregulated in RVF compared to pRV and NF (Benjamini-Hochberg adjusted P < 0.05). ROR2 protein expression correlated linearly to mRNA expression (R² = 0.41, P = 8.1 × 10⁻¹⁸) among all RVs, and to higher right atrial to pulmonary capillary wedge ratio in RVF (R² = 0.40, P = 3.0 × 10⁻⁵). Utilizing Masson's trichrome and ROR2 immunohistochemistry, we identified preferential ROR2 protein expression in fibrotic regions by both cardiomyocytes and noncardiomyocytes. We compared RVF with high and low ROR2 expression, and found that high ROR2 expression was associated with increased expression of the WNT5A/ROR2/Ca²⁺ responsive protease calpain-μ, cleavage of its target FLNA, and FLNA phosphorylation, another marker of activation downstream of ROR2. ROR2 protein expression as a continuous variable, correlated strongly to expression of calpain-μ (R² = 0.25), total FLNA (R² = 0.67), calpain cleaved FLNA (R² = 0.32) and FLNA phosphorylation (R² = 0.62, P < 0.05 for all).

Conclusion: We demonstrate robust reactivation of a fetal WNT gene program, specifically its noncanonical arm, in human RVF characterized by activation of ROR2/calpain mediated cytoskeleton protein cleavage.

Local Mitochondrial ATP Production Regulates Endothelial Fatty Acid Uptake and Transport

Most organs use fatty acids (FAs) as a key nutrient, but little is known of how blood-borne FAs traverse the endothelium to reach underlying tissues. We conducted a small-molecule screen and identified niclosamide as a suppressor of endothelial FA uptake and transport. Structure/activity relationship studies demonstrated that niclosamide acts through mitochondrial uncoupling. Inhibitors of oxidative phosphorylation and the ATP/ADP translocase also suppressed FA uptake, pointing principally to ATP production. Decreasing total cellular ATP by blocking glycolysis did not decrease uptake, indicating that specifically mitochondrial ATP is required. Endothelial FA uptake is promoted by fatty acid transport protein 4 (FATP4) via its ATP-dependent acyl-CoA synthetase activity. Confocal microscopy revealed that FATP4 resides in the endoplasmic reticulum (ER), and that endothelial ER is intimately juxtaposed with mitochondria. Together, these data indicate that mitochondrial ATP production, but not total ATP levels, drives endothelial FA uptake and transport via acyl-CoA formation in mitochondrial/ER microdomains.

Abstract 237: Noncanonical WNT Activation in Human Right Ventricular Heart Failure

Background: Drivers of adaptive and pathologic human right ventricular (RV) remodeling are poorly defined, but there is some evidence that WNT signaling contributes to these processes.

Methods: Using a candidate gene approach, we sought to identify genes specifically expressed in RV failure by assessing the expression of 28 WNT-related genes in the RVs of three groups: human explanted nonfailing donor hearts (NF, n = 29), pre-transplant cardiomyopathy hearts with preserved RV function (pRV, n = 78), and pre-transplant cardiomyopathy hearts with RV failure (RVF, n = 35).

Results: We identified the noncanonical WNT receptor ROR2 as transcriptionally strongly upregulated in RVF compared to pRV and NF (p < 0.05, adjusted for multiple hypothesis testing using Benjamin-Hochberg). By western blot, ROR2 protein expression correlated to mRNA expression (R 2 = 0.41, p = 8.1 x 10-18) and increased linearly with higher right atrial to pulmonary capillary wedge ratio in RVF (R 2 =0.40, p = 3.0 x 10-5). Using trichrome, immunohistochemistry, and RNAscope, we identified preferential ROR2 mRNA and protein expression in fibrotic regions by both cardiomyocytes and noncardiomyocytes. High ROR2 expression correlated with increased expression of a known ROR2 target, the WNT/Ca2+ responsive protease calpain and its target FLNA (R 2 0.25 and 0.67, respectively, p < 0.05), as well as with increased relative phosphorylation of FLNA (R 2 0.62, p < 0.05), a marker of its activation by ROR2. Finally, mice with a range of RVF severity, generated by pulmonary artery constriction, demonstrated a robust increase in ROR2 and FLNA expression compared to sham-treated animals, and ROR2 and FLNA expression correlated strongly with each other (R 2 0.89, p = 6.9 x 10-5) and with increasing RV weight normalized to body weight (R 2 ~0.8, p < 0.001, both).

Conclusion: ROR2 expression in the RV is dramatically increased in humans and mice with severe RVF, and ROR2 expression correlates with worsening RV hemodynamics, calpain expression, FLNA cleavage, and FLNA phosphorylation. Taken together, the data reveal the robust activation of noncanonical WNT signaling in human RVF, and identify ROR2-mediated cytoskeleton protein cleavage as a potential novel target of human pathologic RV remodeling.

Fat, Obesity, and the Endothelium

Endothelial cells line all blood vessels in vertebrates. These cells contribute to whole-body nutrient distribution in a variety of ways, including regulation of local blood flow, regulation of trans-endothelial nutrient transport, and paracrine effects. Obesity elicits dramatic whole-body nutrient redistribution, in particular of fat. We briefly review here recent progress on understanding endothelial fat transport; the impact of obesity on the endothelium; and, conversely, how endothelial function can modulate obesity.

Glucose Metabolism Drives Histone Acetylation Landscape Transitions that Dictate Muscle Stem Cell Function

The impact of glucose metabolism on muscle regeneration remains unresolved. We identify glucose metabolism as a crucial driver of histone acetylation and myogenic cell fate. We use single-cell mass cytometry (CyTOF) and flow cytometry to characterize the histone acetylation and metabolic states of quiescent, activated, and differentiating muscle stem cells (MuSCs). We find glucose is dispensable for mitochondrial respiration in proliferating MuSCs, so that glucose becomes available for maintaining high histone acetylation via acetyl-CoA. Conversely, quiescent and differentiating MuSCs increase glucose utilization for respiration and have consequently reduced acetylation. Pyruvate dehydrogenase (PDH) activity serves as a rheostat for histone acetylation and must be controlled for muscle regeneration. Increased PDH activity in proliferation increases histone acetylation and chromatin accessibility at genes that must be silenced for differentiation to proceed, and thus promotes self-renewal. These results highlight metabolism as a determinant of MuSC histone acetylation, fate, and function during muscle regeneration.

The prognastic efficiencies of modified early warning score and mainz emergency evaluation score for emergency department patients

Background

Recently, there is an increasing interest for scoring systems to evaluate the critically ill patients by means of the severeness of their disease and their availibility for discharge in the emergency departments and intensive care units. Our aim in this study is to evaluate the efficiency of the mEWS and MEES scoring systems in assessing the severeness of the disease and predicting the mid term prognosis of the patients hospitalized following their emergency care in our emergency room.

Material and Method

Patients, who attended to Inonu University Department of Emergency Medicine and hospitalized following their emergency care were included to our study. The effects of age, sex, triage categories, mEWS and MEES scores on the site of hospitalization and mortality was evaluated. Statistical analyses were performed by SPSS for Windows version 16.0. The data was summarized as means, standart deviation and percents. Univariate and multiavriate analyses were performed for risk factor calculations.

Results

The mean age of the patients was 58±19 and 584 (56%) were male. Triage group 1 patients accounted for 21 of all (2%), while 646 (61%) were in group 2 and 384 (37%) were in triage group 3. Of all patients, 341 (32%) were hospitalized to ICU. While discharged patients accounted for 89% (935 patients) of the study group, 116 patients (11%) died at the hospital. The GCS, AVPU and mEWS values were statistically significant by means of patient mortality (P < 0.0001), but the delta MEES value was not (P < 0.127).

Conclusion

The results of our stuy suggests that mEWS evaluation is an effective and reliable tool for predicting outcome and hospitalization areas of ED patients. Our results also displayed that the easily available GCS and AVPU scales are reliable guides in patient management. MEES values, on the other hand, are not convenient for ED use.

Histopathological efficiency of amifostine in radiation‑induced heart disease in rats

OBJECTIVE

Amifositine is a phosphorylated thiol that holds its radioprotective actions by several indirect mechanisms. The purpose of this study was to evaluate histopathologically whether amifositine administration prior to irradiation would have a long‑term protective effect on heart tissue in an experimental rat model.

METHODS

Single dose of 18 Gy radiation and sham radiation exposure were used in related groups. A dose of 200 mg/kg of amifostine was injected intraperitoneally 30 min prior to radiation exposure. Analyses were performed 6 months after irradiation.

RESULTS

Vascular damage and vasculitis were significantly decreased in amifositine treatment group. At the same time, significant thickening of the medial layer was accompanied by vascular damage in irradiated groups. The number and severity of myocyte necrosis were diminished with amifostine.Nevertheless, it could not prevent epicardial and myocardial fibrosis. Severe myocardial fibrosis was observed prominently in three regions, particularly on the apex, tips of papillary muscles and in sites adjacent to the atrioventricular valves. The anti-inflammatory effect of amifostine was not seen.

CONCLUSION

The development of vascular damage and vasculitis were prevented by the use of amifostine. There was a correlation between vascular damage and fibrosis development. According to histopathological results, amifostine could be used as a protective agent against the side effects of radiotherapy (Tab. 4, Fig. 2, Ref. 22).

Registered report: senescence surveillance of pre-malignant hepatocytes limits liver cancer development

The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by conducting replications of 50 papers in the field of cancer biology published between 2010 and 2012. This Registered report describes the proposed replication plan of key experiments from ‘Senescence surveillance of pre-malignant hepatocytes limits liver cancer development’ by Kang et al. (2011), published in Nature in 2011. The experiments that will be replicated are those reported in Figures 3B, 3C, 3E, and 4A. In these experiments, Kang et al. (2011) demonstrate the phenomenon of oncogene-induced cellular senescence and immune-mediated clearance of senescent cells after intrahepatic injection of NRAS (Figures 2I, 3B, 3C, and 3E). Additionally, Kang et al. (2011) show the specific necessity of CD4+ T cells for immunoclearance of senescent cells (Figure 4A). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange, and the results of the replications will be published by eLife.

DOI:http://dx.doi.org/10.7554/eLife.04105.001

Investigation of in vivo radioprotective and in vitro antioxidant and antimicrobial activity of garlic (Allum sativum)

OBJECTIVE

In this study, we aimed to assess the in vivo antioxidant potential via evaluating radioprotective effects in kidney and liver tissues of rats and in vitro antimicrobial and radical scavenger activity of garlic extract.

MATERIALS AND METHODS

Thirty-two mature female Wistar rats were divided into four groups, each consisting of eight rats. Experimental groups were control group (1), GE group (2), irradiation group (3) and both GE and irradiation group (4). For the rats in two groups (group 3 and 4), irradiation was performed on a Cobalt-60 unit using a single fraction of 20 Gy. The GE was given to rats once a day during the month before irradiation and continued for five days after irradiation. The garlic cloves were peeled on crushed ice and 50 g of garlic was cut into small pieces and homogenized in 75 mL of 0.9% NaCI. The concentration of this garlic preparation was considered to be 500 mg/mL on the basis of weight of the starting material (0.5 g/mL). This extract was administered to rats by oral gavage.

RESULTS

Our findings suggest that the use of garlic extract could be useful for addressing the limited therapeutic gain due to the radiation sensitivity of normal tissues adjacent to the tumour which are exposed to radiation, by strengthening the antioxidant system. In vitro and in vivo experiments seem to yield similar conclusions.

CONCLUSIONS

It can be stated that garlic is may be recommended to be sufficiently included in the diets of radiotherapy patients considering its antioxidant and antimicrobial efficacy.

Characteristics of the admissions of cancer patients to emergency department

PURPOSE

To identify the characteristics of admission of patients with cancer in the emergency department of a university hospital.

METHODS

The medical records of 468 emergency department admissions of 336 cancer patients due to medical conditions that were related either to their cancer or its treatment were reviewed and retrospectively analysed.

RESULTS

There were 226 (67%) males and 110 females (37%), with a median age of 60 years (range 17-93). Regarding cancer staging, 156 (46%) patients had locoregional disease and 180 (54%) metastatic disease. Regarding performance status (PS), 321 (69%) were Eastern Cooperative Oncology Group (ECOG) 1-2, and 147 (31%) were ECOG 3-4. The main causes of emergency department admission were cancer progression in 188 (40%) patients, cancer-related signs and symptoms in 203 (43%) and treatment-related complications in 77 (16%). The most common primary cancer sites were the thorax, the gastrointestinal system and the genitourinary system. The medical condition necessitating emergency department admission was local tumor compression in 144 (31%) admissions, infection in 86 (19%) and end-of- life support in 63 (13%).

CONCLUSION

Cancer patients seeking nonscheduled medical care and admitting to emergency departments present many challenges to the emergency physician. Due to the associated high morbidity and mortality, initial evaluation of the patient in the emergency department and therapy have utmost importance in the outcome of the patient. Accurate diagnosis and appropriate treatment of cancer-related problems can improve the quality of life dramatically in patients with cancer.

A probable outbreak of toxoplasmosis among boarding school students in Turkey

In total, 171 students from a boarding school in Izmir, Turkey, with mild and non-specific symptoms of toxoplasmosis, were screened during September-October 2002. All 171 students were seropositive for Toxoplasma gondii IgG and IgM. Of 43 students tested, 40 (93%) had low IgG avidity. None showed evidence of ophthalmic involvement. The data suggest that T. gondii may spread rapidly in close living conditions, possibly following exposure to cat litter. This is the largest recent outbreak of toxoplamosis described in the medical literature.

A retrospective review of perioperative complications in 360 patients who had Burch colposuspension

This retrospective study reviews intraoperative and early complications of Burch colposuspension of 360 patients. Ten patients had massive haemorrhage and 8 of them had a blood transfusion. Three patients had a haematoma. Bladder injuries were noticed in 10 patients, 3 of whom were diagnosed postoperatively. One patient had unilateral ureteral kinking. Urinary retention occurred in 20 patients for more than 10 days and 2 required catheterization for 26 and 32 days respectively. Eighteen patients had a wound infection and 4 had a wound abscess. Twenty nine patients had a urinary infection. Urinary tract injury, haemorrhage and blood transfusion were significantly more common in women having secondary surgery than those having primary surgery. Deep venous thrombosis was diagnosed in 3 patients who had a Burch colposuspension with concomitant abdominal hysterectomy. Knowledge of possible risks and complications of Burch colposuspension may help plan a better preoperative work-up of patients and may minimize the intraoperative complications and increase surgical success and patient satisfaction.