Increased activity of IRE1 improves the clinical presentation of EAE

Activation of the endoplasmic reticulum (ER) stress sensor inositol-requiring enzyme-1α (IRE1α) contributes to neuronal development and is known to induce neuronal remodeling in vitro and in vivo. On the contrary, excessive IRE1 activity is often detrimental and may contribute to neurodegeneration. To determine the consequences of increased activation of IRE1α, we used a mouse model expressing a C148S variant of IRE1α with increased and sustained activation. Surprisingly, the mutation did not affect the differentiation of highly secretory antibody-producing cells but exhibited a beneficial effect in a mouse model of experimental autoimmune encephalomyelitis (EAE). Although mechanical allodynia was unaffected, significant improvement in motor function was found in IRE1C148S mice with EAE relative to wild type (WT) mice. Coincident with this improvement, there was reduced microgliosis in the spinal cord of IRE1C148S mice, with reduced expression of proinflammatory cytokine genes. This was accompanied by reduced axonal degeneration and enhanced 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) levels, suggesting improved myelin integrity. Interestingly, while the IRE1C148S mutation is expressed in all cells, the reduction in proinflammatory cytokines and in the microglial activation marker ionized calcium-binding adapter molecule (IBA1), along with preservation of phagocytic gene expression, all point to microglia as the cell type contributing to the clinical improvement in IRE1C148S animals. Our data suggest that sustained increase in IRE1α activity can be beneficial in vivo, and that this protection is cell type and context dependent. Considering the overwhelming but conflicting evidence for the role of ER stress in neurological diseases, a better understanding of the function of ER stress sensors in physiological contexts is clearly needed.

Increased activity of IRE1 improves the clinical presentation of EAE

Activation of the ER stress sensor IRE1α contributes to neuronal development and is known to induce neuronal remodeling in vitro and in vivo. On the other hand, excessive IRE1 activity is often detrimental and may contribute to neurodegeneration. To determine the consequences of increased activation of IRE1α, we used a mouse model expressing a C148S variant of IRE1α with increased and sustained activation. Surprisingly, the mutation did not affect the differentiation of highly secretory antibody-producing cells, but exhibited a strong protective effect in a mouse model of experimental autoimmune encephalomyelitis (EAE). Significant improvement in motor function was found in IRE1C148S mice with EAE relative to WT mice. Coincident with this improvement, there was reduced microgliosis in the spinal cord of IRE1C148S mice, with reduced expression of pro-inflammatory cytokine genes. This was accompanied by reduced axonal degeneration and enhanced CNPase levels, suggestiing improved myelin integrity. Interestingly, while the IRE1C148S mutation is expressed in all cells, the reduction in proinflammatory cytokines and in the activation of microglial activation marker IBA1, along with preservation of phagocytic gene expression, all point to microglia as the cell type contributing to the clinical improvement in IRE1C148S animals. Our data suggest that sustained increase in IRE1α activity can be protective in vivo, and that this protection is cell type and context dependent. Considering the overwhelming but conflicting evidence for the role of the ER stress in neurological diseases, a better understanding of the function of ER stress sensors in physiological contexts is clearly needed.

The novel noninvasive method for prediction of long-term specific therapy efficacy in patients with IPAH and inoperable CTEPH

Introduction

The main aim of the treatment in patients (pts) with idiopathic pulmonary arterial hypertension (IPAH) is the achivement of low risk of fatal events during the year, that reflecting the complex of nonivasive and invasive parameters presented in the risk stratification scale of ESC and ERS 2015 guidelines. However, in pts with chronic thromboembolic pulmonary hypertension (CTEPH) there is a lack of evidence to use this scale. Also there is some limitation to perform invasive diagnostics in every patient for complex risk assessment. Thus, the searching for the novel noninvasive markers for prediction of treatment efficacy need further investigation.

Purpose

To develop the novel approach for predicting of long-term specific therapy efficacy using noninvasive methods of diagnostic in IPAH and CTEPH pts.

Methods

The study included 88 IPAH and 38 inoperable CTEPH pts. At the time of diagnosis verification and after 1 year of treatment the complex assessment, including 6-minute walking test, cardiopulmonary exercise test, 2D and 3D Echo, right heart catheterization, NT-proBNP level assessment were made. The efficacy of treatment was determined as achievement of cardiac index (CI) equal or more than 2,5 l/min/m2 after 1 year of treatment. To create a model, predicting long-term specific therapy efficacy the classification trees with the full enumeration method for one-dimensional branches C&RT were used. The impact of factors in prediction of the long-term specific therapy efficacy was demonstrated in the ranks of significance of predictors in units (U).

Results

At baseline all pts with IPAH/inoperable CTEPH were out of the low-risk area. Whereas, after 1 year of treatment 27% of IPAH/CTEPH pts achieved a low risk of fatal events.

To develop a model for predicting of the long-term specific therapy efficacy (>1 year) in patients with IPAH/ CTEPH the most significant predictors of achievement of CI equal or more, than 2.5 l/min/m2 were: age (73 U), right ventricular end-diastolic/end-systolic volumes (85 U/84 U) at the time of diagnosis verification, and the dynamics of NT-proBNP (100 U.).

According to the most valuble factors the model of long-term therapy efficacy was created: the value of dynamic (Δ) of NT-proBNP from >−376,4 to <30,4 pg/ml after 12 months of treatment with combination of right ventricular end-diastolic volume <150,5 ml at the time of diagnosis verification predict the therapy efficacy.

Conclusion

The implementation of novel noninvasive method, that predict specific therapy efficacy, allows making a timely decision of therapy escalation in IPAH and CTEPH pts by the first and subsequent years of treatment.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): National medical research center of Cardiology, Moscow

A Novel Inhibitor of HSP70 Induces Mitochondrial Toxicity and Immune Cell Recruitment in Tumors

The protein chaperone HSP70 is overexpressed in many cancers including colorectal cancer, where overexpression is associated with poor survival. We report here the creation of a uniquely acting HSP70 inhibitor (HSP70i) that targets multiple compartments in the cancer cell, including mitochondria. This inhibitor was mitochondria toxic and cytotoxic to colorectal cancer cells, but not to normal colon epithelial cells. Inhibition of HSP70 was efficacious as a single agent in primary and metastatic models of colorectal cancer and enabled identification of novel mitochondrial client proteins for HSP70. In a syngeneic colorectal cancer model, the inhibitor increased immune cell recruitment into tumors. Cells treated with the inhibitor secreted danger-associated molecular patterns (DAMP), including ATP and HMGB1, and functioned effectively as a tumor vaccine. Interestingly, the unique properties of this HSP70i in the disruption of mitochondrial function and the inhibition of proteostasis both contributed to DAMP release. This HSP70i constitutes a promising therapeutic opportunity in colorectal cancer and may exhibit antitumor activity against other tumor types. SIGNIFICANCE: These findings describe a novel HSP70i that disrupts mitochondrial proteostasis, demonstrating single-agent efficacy that induces immunogenic cell death in treated tumors.

A Rare TP53 Mutation Predominant in Ashkenazi Jews Confers Risk of Multiple Cancers

Germline mutations in TP53 cause a rare high penetrance cancer syndrome, Li-Fraumeni syndrome (LFS). Here, we identified a rare TP53 tetramerization domain missense mutation, c.1000G>C;p.G334R, in a family with multiple late-onset LFS-spectrum cancers. Twenty additional c.1000G>C probands and one c.1000G>A proband were identified, and available tumors showed biallelic somatic inactivation of TP53. The majority of families were of Ashkenazi Jewish descent, and the TP53 c.1000G>C allele was found on a commonly inherited chromosome 17p13.1 haplotype. Transient transfection of the p.G334R allele conferred a mild defect in colony suppression assays. Lymphoblastoid cell lines from the index family in comparison with TP53 normal lines showed that although classical p53 target gene activation was maintained, a subset of p53 target genes (including PCLO, PLTP, PLXNB3, and LCN15) showed defective transactivation when treated with Nutlin-3a. Structural analysis demonstrated thermal instability of the G334R-mutant tetramer, and the G334R-mutant protein showed increased preponderance of mutant conformation. Clinical case review in comparison with classic LFS cohorts demonstrated similar rates of pediatric adrenocortical tumors and other LFS component cancers, but the latter at significantly later ages of onset. Our data show that TP53 c.1000G>C;p.G334R is found predominantly in Ashkenazi Jewish individuals, causes a mild defect in p53 function, and leads to low penetrance LFS. SIGNIFICANCE: TP53 c.1000C>G;p.G334R is a pathogenic, Ashkenazi Jewish-predominant mutation associated with a familial multiple cancer syndrome in which carriers should undergo screening and preventive measures to reduce cancer risk.

P6161The evaluation of the effectiveness of the treatment of patients with chronic thromboembolic pulmonary hypertension using subtraction CT pulmonary angiography

Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening delayed complication of acute pulmonary embolism. It is characterized by chronic obstruction of the branches of the pulmonary artery, arteriopathy and vasoconstriction of small vessels, that ultimately leading to right ventricular failure. Subtraction CT pulmonary angiography (CTPA) allows to perform a comprehensive the assessment of the state of the vascular bed and pulmonary perfusion, it is especially important for pathological changes in the distal branches of the pulmonary artery. Analysis of perfusion defects in combination with the standard protocol of CTPA can increase the diagnostic value of the method in examining patients with CTEPH that will select the optimal treatment strategy with the possibility of an objective assessment of its effectiveness.

Purpose

The aim of this work was to determine the possibilities of the method of subtraction CTPA in the evaluation of the effectiveness of the treatment of patients with CTEPH.

Methods and materials

Primary and repeated subtraction CTPA was performed 36 patients with the diagnosis of CTEPH (10 patients after surgical treatment, 13 patients after endovascular treatment and 13 patients after initiation of PAH-specific therapy) (figure).All patients were examined on 320-detector row CT scanner using the standard protocol Lung subtraction. Using subtraction CTPA was calculated of CT-scores of obstruction and perfusion defect. The data of primary and repeated CT studies were compared with the clinical and hemodynamic status of patients. CT color-coded iodine images were produced by subtraction of non-contrast from contrast images.

Results

According to repeated CTPA a decrease of the degree of obstruction was observed in 18 out of 36 (50%) patients: in 10 (100%) patients from the surgical treatment group and 8 (61.5%) patients from the endovascular treatment group. Subtraction CTPA was a good quality for interpreting perfusion maps in 28 of 36 (77.8%) patients.Evaluation of the dynamics of perfusion disorders was not performed in 8 patients: in 3 patients from the surgical treatment group and 5 patients from the endovascular treatment group. Improvement of lung perfusion according to perfusion maps was determined in 18 out of 28 (64.3%) patients: 7 (100%) patients from the surgical treatment group, 5 (62.5%) patients from the endovascular treatment group, and 6 (46.2%) patients from the group of drug treatment. Improvement of clinical and hemodynamic parameters was observed in all patients in the surgical and endovascular treatment groups. There was no statistically significant improvement in clinical and hemodynamic parameters in the drug treatment group.

Conclusion

The results of the study demonstrated the possibility of using subtraction CTPA for an objective assessment of the effectiveness of the treatment of patients with CTEPH.

P6007Cardiovascular coupling and elastic properties of pulmonary artery in different phenotypes of patients with pulmonary hypertension

Background

The cardiovascular (CV) coupling and elastic properties of pulmonary artery (PA) were assessed only in a few studies, and their role in determination of severity in IPAH/CTEPH patients need further investigation.

Purpose

To assess CV coupling and elastic properties of PA in different phenotypes of IPAH and inoperable CTEPH pts at baseline and in dynamics after riociguat treatment using 2D and 3D Echo.

Methods

The study included 88 IPAH and 38 inoperable CTEPH pts. Pts were divided into groups: according to the age at time of diagnosis verification (age <50 (n=69)/age >50 years (n=57)); WHO functional class (FC) (FC I–II (n=43)/ FC III–IV (n=83)); mean pulmonary arterial pressure (mPAP) (mPAP <51 (n=47)/ mPAP>51 mmHg (n=79)). For the first time we assessed right-ventricular (RV)–PA coupling, left ventricular (LV)–Aorta (Ao) coupling, PA elastic properties (strain, global capacitance and stiffness, β stiffness index, Peterson's elastic modulus) at the time of diagnosis verification and in dynamics after 6 months of riociguat treatment in IPAH/CTEPH pts with different demographic, functional and hemodynamics status using 2D and 3D Echo. CV coupling was calculated as the ratio of PA or Ao effective elastance (Ea) and RV or LV end-systolic elastance (Es).

Results

IPAH/CTEPH pts older than 50 years at the time of diagnosis verification had significantly more reduced PA strain (7.7 [3.3; 11]%), increased β stiffness index (9 [6.5; 23.6]) and Peterson's elastic modulus (797 [370; 1391]x105 Pa) compared to the younger pts (3.5 [3; 6.7]%, 23.7 [14.6; 31.6], 1666 [833; 2000]x105 Pa, respectively). Pts with FC III-IV (WHO) had significantly increased Es LV (4.5 [3.7; 5] mmHg/ml, decreased PA strain (4 [3; 7]%), increased β stiffness index (21 [11; 30]) and Peterson's elastic modulus (1410 [791; 2000]x105 Pa) compared to the pts with FC I–II (3.6 [3; 4] mmHg/ml, 7.4 [6.4; 13]%, 12.7 [7.5; 16.5], 714 [370; 909]x105 Pa, respectively). In pts with mPAP >51 mmHg the PA global stiffness (1.1 [0.9; 1.5] mmHg/ml and Es LV (4.5 [3.8; 6] mmHg/ml) were significantly increased compared to the pts with mPAP <51 mmHg (0.8 [0.6; 1.1] mmHg/ml and 3.9 [3; 4.5] mmHg/ml, respectively). The significant correlation between RV-PA coupling and RV ejection fraction (EF) (3D Echo) (r=−0.73; p<0.05), RV-PA coupling and NT-proBNP (r=0.61; p<0.05), moderate correlation between PA strain and RV EF (r=0.47; p<0.05) were found. After 6 months of riociguat treatment in 24 IPAH/CTEPH pts with II-III FC the significant reduction of RV-PA coupling due to Ea PA decrease, also as elevation of LV-Ao coupling due to Es LV decrease were revealed in addition to reverse remodeling of RV, and improvement in PA elastic properties, functional and hemodynamic status.

Dynamics of CV coupling

Conclusion

The evaluation of CV coupling and PA elastic properties at the time of diagnosis verification and in dynamics can be used in clinical practice to assess the disease severity and the efficacy of the treatment in IPAH and inoperable CTEPH pts.

Tales of diversity: Genomic and morphological characteristics of forty-six Arthrobacter phages

The vast bacteriophage population harbors an immense reservoir of genetic information. Almost 2000 phage genomes have been sequenced from phages infecting hosts in the phylum Actinobacteria, and analysis of these genomes reveals substantial diversity, pervasive mosaicism, and novel mechanisms for phage replication and lysogeny. Here, we describe the isolation and genomic characterization of 46 phages from environmental samples at various geographic locations in the U.S. infecting a single Arthrobacter sp. strain. These phages include representatives of all three virion morphologies, and Jasmine is the first sequenced podovirus of an actinobacterial host. The phages also span considerable sequence diversity, and can be grouped into 10 clusters according to their nucleotide diversity, and two singletons each with no close relatives. However, the clusters/singletons appear to be genomically well separated from each other, and relatively few genes are shared between clusters. Genome size varies from among the smallest of siphoviral phages (15,319 bp) to over 70 kbp, and G+C contents range from 45-68%, compared to 63.4% for the host genome. Although temperate phages are common among other actinobacterial hosts, these Arthrobacter phages are primarily lytic, and only the singleton Galaxy is likely temperate.