Impaired T cell IRE1α/XBP1 signaling directs inflammation in experimental heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a widespread syndrome with limited therapeutic options and poorly understood immune pathophysiology. Using a 2-hit preclinical model of cardiometabolic HFpEF that induces obesity and hypertension, we found that cardiac T cell infiltration and lymphoid expansion occurred concomitantly with cardiac pathology and that diastolic dysfunction, cardiomyocyte hypertrophy, and cardiac phospholamban phosphorylation were T cell dependent. Heart-infiltrating T cells were not restricted to cardiac antigens and were uniquely characterized by impaired activation of the inositol-requiring enzyme 1α/X-box-binding protein 1 (IRE1α/XBP1) arm of the unfolded protein response. Notably, selective ablation of XBP1 in T cells enhanced their persistence in the heart and lymphoid organs of mice with preclinical HFpEF. Furthermore, T cell IRE1α/XBP1 activation was restored after withdrawal of the 2 comorbidities inducing HFpEF, resulting in partial improvement of cardiac pathology. Our results demonstrated that diastolic dysfunction and cardiomyocyte hypertrophy in preclinical HFpEF were T cell dependent and that reversible dysregulation of the T cell IRE1α/XBP1 axis was a T cell signature of HFpEF.

T-Cell MyD88 Is a Novel Regulator of Cardiac Fibrosis Through Modulation of T-Cell Activation

BACKGROUND

Cardiac inflammation in heart failure is characterized by the presence of damage-associated molecular patterns, myeloid cells, and T cells. Cardiac damage-associated molecular patterns provide continuous proinflammatory signals to myeloid cells through TLRs (toll-like receptors) that converge onto the adaptor protein MyD88 (myeloid differentiation response 88). These induce activation into efficient antigen-presenting cells that activate T cells through their TCR (T-cell receptor). T-cell activation results in cardiotropism, cardiac fibroblast transformation, and maladaptive cardiac remodeling. T cells rely on TCR signaling for effector function and survival, and while they express MyD88 and damage-associated molecular pattern receptors, their role in T-cell activation and cardiac inflammation is unknown.

METHODS

We performed transverse aortic constriction in mice lacking MyD88 in T cells and analyzed remodeling, systolic function, survival, and T-cell activation. We profiled wild type versus Myd88-/- mouse T cells at the transcript and protein level and performed several functional assays.

RESULTS

Analysis of single-cell RNA-sequencing data sets revealed that MyD88 is expressed in mouse and human cardiac T cells. MyD88 deletion in T cells resulted in increased levels of cardiac T-cell infiltration and fibrosis in response to transverse aortic constriction. We discovered that TCR-activated Myd88-/- T cells had increased proinflammatory signaling at the transcript and protein level compared with wild type, resulting in increased T-cell effector functions such as adhesion, migration across endothelial cells, and activation of cardiac fibroblast. Mechanistically, we found that MyD88 modulates T-cell activation and survival through TCR-dependent rather than TLR-dependent signaling.

CONCLUSIONS

Our results outline a novel intrinsic role for MyD88 in limiting T-cell activation that is central to tune down cardiac inflammation during cardiac adaptation to stress.

Long-Range Energy Transfer in Strongly Coupled Donor-Acceptor Phototransistors

Strong light-matter coupling offers a way to tailor the optoelectronic properties of materials. Energy transfer between strongly coupled donor-acceptor pairs shows remarkable efficiency beyond the Förster distance via coupling through a confined photon. This long-range energy transfer is facilitated through the collective nature of polaritonic states. Here, the cooperative, strong coupling of a donor (MoS₂ monolayer) and an acceptor (BRK) generates mixed polaritonic states. The photocurrent spectrum of the MoS₂ monolayer is measured in a field effect transistor while coupling the two oscillators to the confined cavity mode. The strongly coupled system shows efficient energy transfer, which is observed through the photoresponsivity even the donor and acceptor are physically separated by 500 Å. These studies are further correlated with the Hopfield coefficients and the overlap integral of the lower polaritonic and uncoupled/dark states. Cavity detuning and distance-dependent studies support the above evidence. These observations open new avenues for using long-range interaction of polaritonic states in optoelectronic devices.

Swelling-Activated, Soft Mechanochemistry in Polymer Materials

Swelling in polymer materials is a ubiquitous phenomenon. At a molecular level, swelling is dictated by solvent-polymer interactions, and has been thoroughly studied both theoretically and experimentally. Favorable solvent-polymer interactions result in the solvation of polymer chains. For polymers in confined geometries, such as those that are tethered to surfaces, or for polymer networks, solvation can lead to swelling-induced tensions. These tensions act on polymer chains and can lead to stretching, bending, or deformation of the material both at the micro- and macroscopic scale. This Invited Feature Article sheds light on such swelling-induced mechanochemical phenomena in polymer materials across dimensions, and discusses approaches to visualize and characterize these effects.

Effect of microwave drying of paddy on milling characteristics, cooking quality, and microstructure of rice

Effect of microwave drying on milling, cooking, and microstructure characteristic of paddy rice in comparison to hot air drying was assessed in the present study. Results revealed that modified microwave drying significantly (P < 0.05) affected the milling quality of paddy. Raw paddy had head rice recovery of 49.63%, while after microwave drying, the head rice recovery increased by 6.73% in comparison to hot air drying. Microwave drying brought significant changes in the colour characteristic of rice as it had total colour change of 13.50 in comparison to 10.93 by hot air drying. Cooking time and water uptake ratio after microwave drying increased to 31.46 min and 3.16%, in comparison to 27.05 min and 2.65% for hot air dried samples, respectively. Scanning Electron Microscope images revealed that both hot air and microwave dried rice had a coarse surface and large starch particles, while starch structure was more damaged in hot air drying, however, agglomeration of protein-starch matrix was more uniform in microwave dried samples due to modification of the microwave applicator that prevented thermal decomposition. It was recommended that paddy may be dried using a modified microwave applicator with a shorter duration and a better quality.

Antigen presentation by cardiac fibroblasts promotes cardiac dysfunction

Heart failure (HF) is a leading cause of morbidity and mortality. Studies in animal models and patients with HF revealed a prominent role for CD4+ T cell immune responses in the pathogenesis of HF and highlighted an active crosstalk between cardiac fibroblasts and IFNγ producing CD4+ T cells that results in profibrotic myofibroblast transformation. Whether cardiac fibroblasts concomitantly modulate pathogenic cardiac CD4+ T cell immune responses is unknown. Here we show report that murine cardiac fibroblasts express major histocompatibility complex type II (MHCII) in two different experimental models of cardiac inflammation. We demonstrate that cardiac fibroblasts take up and process antigens for presentation to CD4+ T cells via MHCII induced by IFNγ. Conditional deletion of MhcII in cardiac fibroblasts ameliorates cardiac remodelling and dysfunction induced by cardiac pressure overload. Collectively, we demonstrate that cardiac fibroblasts function as antigen presenting cells (APCs) and contribute to cardiac fibrosis and dysfunction through IFNγ induced MHCII.

Sialomucin CD43 Plays a Deleterious Role in the Development of Experimental Heart Failure Induced by Pressure Overload by Modulating Cardiac Inflammation and Fibrosis

Sialomucin CD43 is a transmembrane protein differentially expressed in leukocytes that include innate and adaptive immune cells. Among a variety of cellular processes, CD43 participates in T cell adhesion to vascular endothelial cells and contributes to the progression of experimental autoimmunity. Sequential infiltration of myeloid cells and T cells in the heart is a hallmark of cardiac inflammation and heart failure (HF). Here, we report that CD43-/- mice have improved survival to HF induced by transverse aortic constriction (TAC). This enhanced survival is associated with improved systolic function, decreased cardiac fibrosis, and significantly reduced T cell cardiac infiltration in response to TAC compared to control wild-type (WT) mice. Lack of CD43 did not alter the number of myeloid cells in the heart, but resulted in decreased cardiac CXCL10 expression, a chemoattractant for T cells, and in a monocyte shift to anti-inflammatory macrophages in vitro. Collectively, these findings unveil a novel role for CD43 in adverse cardiac remodeling in pressure overload induced HF through modulation of cardiac T cell inflammation.

Spin-Boson Quantum Phase Transition in Multilevel Superconducting Qubits

Superconducting circuits are currently developed as a versatile platform for the exploration of many-body physics, by building on nonlinear elements that are often idealized as two-level qubits. A classic example is given by a charge qubit that is capacitively coupled to a transmission line, which leads to the celebrated spin-boson description of quantum dissipation. We show that the intrinsic multilevel structure of superconducting qubits drastically restricts the validity of the spin-boson paradigm due to phase localization, which spreads the wave function over many charge states. Numerical renormalization group simulations also show that the quantum critical point moves out of the physically accessible range in the multilevel regime. Imposing charge discreteness in a simple variational state accounts for these multilevel effects, which are relevant for a large class of devices.

A retrospective audit of endoscopic duodenal biopsies to uncover undetected Coeliac disease in Malaysian patients

BACKGROUND

Coeliac disease, an autoimmune enteropathy related to gluten sensitivity was hitherto thought to be rare in Asia. Recent data however suggests that Celiac disease may be under-diagnosed in Asia.

OBJECTIVE

The aim of this audit was to determine the frequency of histological changes compatible with Coeliac disease among patients undergoing elective diagnostic oesaphago-gastro-duodenoscopy (OGDS) under the care of a single practitioner in a Malaysian hospital.

MATERIALS AND METHODS

The archived endoscopically obtained duodenal biopsy specimens of 241 consecutive Malaysian subjects undergoing elective diagnostic (OGDS) were reviewed by a pathologist blinded to the clinical data. Based on intra-epithelial lymphocyte counts, crypt hyperplasia and villous atrophy, each subject was assigned to one of the categories of the Modified Marsh classification for the histological diagnosis of Coeliac disease. The clinical charts of all subjects were reviewed by a single gastroenterologist blinded to the findings of the histological review.

RESULTS

Of the 241 study subjects, 132 (54.8%) were females. There were 56 (23.2%) Malays, 90 (37.3%) Chinese, 88 (36.5%) Indians and seven (2.9%) from the other category. The median age of the study sample was 49 years (range 15- 88 years). The OGDS was done as part of screening in 15(6.2%) subjects while in the remaining it was part of the investigation of a clinical problem. Based on histological findings, none of the subjects could be assigned to a modified Marsh class of >1. The prevalence of histological changes compatible with Coeliac disease in the study was 0% (binomial exact one-sided 97.5 % confidence interval 0- 1.52%).

CONCLUSION

In conclusion, this audit provides no evidence that active Coeliac disease is significantly under-detected among symptomatic patients presenting for diagnostic OGDS. The possibility that a significant number may have potential coeliac disease cannot be excluded.

Gestational diabetes mellitus (GDM) and adverse pregnancy outcome in South Asia: A systematic review

INTRODUCTION

The prevalence of gestational diabetes mellitus (GDM) is increasing in developing countries including the South Asian Nations. The current study aimed to examine the association of GDM with adverse pregnancy outcomes from foetal and maternal perspectives in South Asia.

METHODS

A systematic review was conducted including primary studies published since January 2020 from South Asian countries. Following electronic databases were searched to locate the articles: MEDLINE, EMBASE and EMCARE. Data were extracted using a customized extraction tool and methodological quality of the included studies was assessed using modified Effective Public Health Practice Project (EPHPP) quality assessment tool. Narrative synthesis was performed as statistical pooling was not possible due to the heterogeneous nature of the studies.

RESULTS

Eight studies were included in the review. Overall, the review found a positive correlation between GDM and adverse foetal outcomes such as macrosomia, neonatal hyperglycaemia, intrauterine growth retardation (IUGR), stillbirths and low birthweight (LBW), but the findings were not conclusive. GDM was also positively associated with preeclampsia but the association between GDM and C-section delivery was not conclusive.

CONCLUSION

Policymakers, public health practitioners and researchers in South Asia should take in to account the link between GDM and adverse pregnancy outcomes while designing interventions to promote maternal health in South Asia. Researchers should focus on conducting longitudinal studies in future to clearly understand the epidemiology and pathobiology of this issue.

Abstract 116: T Cells Contribute To Diastolic Dysfunction And Cardiac Hypertrophy In A Preclinical Model Of Heart Failure With Preserved Ejection Fraction

Introduction: Heart Failure with Preserved Ejection Fraction (HFpEF) is a prevalent cardiovascular syndrome with no curative therapies, characterized by diastolic dysfunction, preserved systolic function, and decreased expression of unfolded protein response (UPR) genes in the heart. Obesity and hypertension are risk factors for HFpEF and are intimately associated with systemic inflammation. However, the inflammatory mechanisms driving HFpEF remain largely unexplored.

Hypothesis: We hypothesized that nitrosative stress induced by obesity and hypertension programs T cells to infiltrate the heart and drive cardiac pathology in HFpEF.

Methods: Using a recently established model of HFpEF, we modeled obesity and hypertension in male C57/BL6 (wild-type, WT), T cell receptor alpha-deficient ( Tcra-/-), and Nur77-GFP reporter mice for T cell receptor engagement, using a high-fat diet (HFD) and L-NAME for 5 weeks, or standard chow (STD) as controls. Invasive hemodynamic analyses were used to assess cardiac function, and the heart and lymphoid organs were harvested to characterize immune cell populations by flow cytometry, histology, and gene expression of cardiac remodeling.

Results: In WT mice, HFD/L-NAME induced significant cardiac infiltration of T cells alongside the hallmarks of HFpEF. HFD/L-NAME significantly expanded CD62 lo CD44 hi effector T cells in the mediastinal lymph nodes and spleen. Nur77-GFP mice revealed no antigen engagement by T cells in the heart, however, T cells sorted out of the lymphoid organs of HFpEF mice had significantly decreased gene expression of the UPR gene spliced X box-binding protein 1 (XBP1s) compared to controls, suggesting a T cell intrinsic dysregulation of the UPR, and T cell phenotypic changes independent of TCR engagement in the heart. Strikingly, Tcra-/- mice did not develop diastolic dysfunction or cardiomyocyte hypertrophy, demonstrating a novel role for T cells in this experimental model of HFpEF.

Conclusions: We conclude diastolic dysfunction and cardiomyocyte hypertrophy in HFpEF is T cell dependent. Ongoing studies are determining whether the observed intrinsic T cell changes in XBP1s prime T cells for cardiac infiltration and effector function that results in diastolic dysfunction and HFpEF.

Abstract 104: Deletion Of Myd88 In T-Cells Worsens Pathology In A Mouse Model Of Non-Ischemic Heart Failure Through Enhanced T-Cell Survival And Effector Function:

Background: Heart failure (HF) is a leading cause of death worldwide, associated with cardiac and systemic inflammation. However, no anti-inflammatory therapies have shown success thus far. Damage associated molecular patterns (DAMPs) released in the heart can activate myeloid cells to promote antigen presentation to T-cells, which infiltrate the heart and participate in adverse cardiac remodeling. DAMP signaling converges onto the adaptor protein “Myeloid differentiation primary response 88” (MyD88). DAMP receptors and MyD88 are also expressed in T-cells, but their role in T-cell activation is unclear, and is unknown in the context of HF. We hypothesized that T-cell recognition of DAMPs through MyD88 causes “bystander activation” of T-cells and contributes to cardiac pathology in HF.

Methods and Results: We reconstituted Tcra -/- mice, normally protected from HF, with WT or Myd88 -/- Type 1 helper T-cells (Th1) in the onset of transaortic constriction (TAC), a well-established model of HF. Surprisingly, we found that mice given Myd88 -/- Th1 cells exhibited significantly higher levels of cardiac T-cell infiltration, more severe fibrosis, and lower fractional shortening than mice given WT Th1 cells. We found that WT and Myd88 -/- Th1 cells had similar levels of IFNγ and Tbx21 by intracellular staining and RT-qPCR, indicating that MyD88 does not alter Th1 differentiation. However, Myd88 -/- Th1 cells secreted higher levels of IL-2 and TNFα, suggesting enhanced proliferative and pro-inflammatory effector function. We performed viability studies using live cell microscopy and measuring propidium iodide incorporation in real time, as well as by flow cytometry, and found that Myd88 -/- Th1 cells have a survival advantage compared to WT Th1 cells. Moreover, we found that Myd88 -/- Th1 cells exhibited higher levels of adhesion to ICAM-1 and VCAM-1, protein ligands involved in T-cell recruitment, compared to WT Th1 cells when perfused under conditions of shear flow.

Conclusion: Together, these data demonstrate that T-cell MyD88 limits T-cell mediated pathology in HF by modulating Th1 effector function, survival, and adhesion ability. We identify novel role for T-cell MyD88 in cardiac inflammation that may be modulated in HF.

Enhanced Charge Transport in Two-Dimensional Materials through Light-Matter Strong Coupling

Strong light-matter interaction of functional materials is emerging as a promising area of research. Recent experiments suggest that material properties like charge transport can be controlled by coupling to a vacuum electromagnetic field. Here, we explored the design of a Fabry-Perot cavity in a field-effect transistor configuration and studied the charge transport in two-dimensional materials. The optical and electrical measurements of strongly coupled WS₂ suggest an enhancement of electron transport at room temperature. Electron mobility is enhanced more than 50 times at ON resonance conditions. Similarly, I_on/I_off ratio of the device increased by 2 orders of magnitude without chemical modification of the active layer. Cavity tuning and coupling strength-dependent studies support the evidence of modifying the electronic properties of the coupled system. A clear correlation in the effective mass of the polaritonic state and Schottky barrier height indicates a collective nature of light-matter interaction.

Amino acid-based H2S donors: N-thiocarboxyanhydrides that release H2S with innocuous byproducts

A library of N-thiocarboxyanhydrides (NTAs) derived from natural amino acids with benign byproducts and controlled H2S-release kinetics is reported. Minimal acute in vitro toxicity was observed in multiple cell lines, while longer-term toxicity in cancer cells was observed, with slow-releasing donors exhibiting the greatest cytotoxic effects.

Endothelial STING controls T cell transmigration in an IFNI-dependent manner

The stimulator of IFN genes (STING) protein senses cyclic dinucleotides released in response to double-stranded DNA and functions as an adaptor molecule for type I IFN (IFNI) signaling by activating IFNI-stimulated genes (ISG). We found impaired T cell infiltration into the peritoneum in response to TNF-α in global and EC-specific STING-/- mice and discovered that T cell transendothelial migration (TEM) across mouse and human endothelial cells (EC) deficient in STING was strikingly reduced compared with control EC, whereas T cell adhesion was not impaired. STING-/- T cells showed no defect in TEM or adhesion to EC, or immobilized endothelial cell-expressed molecules ICAM1 and VCAM1, compared with WT T cells. Mechanistically, CXCL10, an ISG and a chemoattractant for T cells, was dramatically reduced in TNF-α-stimulated STING-/- EC, and genetic loss or pharmacologic antagonisms of IFNI receptor (IFNAR) pathway reduced T cell TEM. Our data demonstrate a central role for EC-STING during T cell TEM that is dependent on the ISG CXCL10 and on IFNI/IFNAR signaling.

Self-assembly of protein-polymer conjugates for drug delivery

Protein-polymer conjugates are a class of molecules that combine the stability of polymers with the diversity, specificity, and functionality of biomolecules. These bioconjugates can result in hybrid materials that display properties not found in their individual components and can be particularly relevant for drug delivery applications. Engineering amphiphilicity into these bioconjugate materials can lead to phase separation and the assembly of high-order structures. The assembly, termed self-assembly, of these hierarchical structures entails multiple levels of organization: at each level, new properties emerge, which are, in turn, influenced by lower levels. Here, we provide a critical review of protein-polymer conjugate self-assembly and how these materials can be used for therapeutic applications and drug delivery. In addition, we discuss central bioconjugate design questions and propose future perspectives for the field of protein-polymer conjugate self-assembly.

Transcriptome and proteome mapping in the sheep atria reveal molecular featurets of atrial fibrillation progression

AIMS

Atrial fibrillation (AF) is a progressive cardiac arrhythmia that increases the risk of hospitalization and adverse cardiovascular events. There is a clear demand for more inclusive and large-scale approaches to understand the molecular drivers responsible for AF, as well as the fundamental mechanisms governing the transition from paroxysmal to persistent and permanent forms. In this study, we aimed to create a molecular map of AF and find the distinct molecular programmes underlying cell type-specific atrial remodelling and AF progression.

METHODS AND RESULTS

We used a sheep model of long-standing, tachypacing-induced AF, sampled right and left atrial tissue, and isolated cardiomyocytes (CMs) from control, intermediate (transition), and late time points during AF progression, and performed transcriptomic and proteome profiling. We have merged all these layers of information into a meaningful three-component space in which we explored the genes and proteins detected and their common patterns of expression. Our data-driven analysis points at extracellular matrix remodelling, inflammation, ion channel, myofibril structure, mitochondrial complexes, chromatin remodelling, and genes related to neural function, as well as critical regulators of cell proliferation as hallmarks of AF progression. Most important, we prove that these changes occur at early transitional stages of the disease, but not at later stages, and that the left atrium undergoes significantly more profound changes than the right atrium in its expression programme. The pattern of dynamic changes in gene and protein expression replicate the electrical and structural remodelling demonstrated previously in the sheep and in humans, and uncover novel mechanisms potentially relevant for disease treatment.

CONCLUSIONS

Transcriptomic and proteomic analysis of AF progression in a large animal model shows that significant changes occur at early stages, and that among others involve previously undescribed increase in mitochondria, changes to the chromatin of atrial CMs, and genes related to neural function and cell proliferation.

Role of magnetic resonance imaging in breast cancer management

Magnetic resonance imaging (MRI) of the breast is primarily used as a supplemental tool to breast screening with mammography or ultrasound. A breast MRI is mainly used for women who have been diagnosed with breast cancer, to help measure the size of the cancer, look for other tumors in the breast, and to check for tumors in the opposite breast. For certain women at high risk for breast cancer, a screening MRI is recommended along with a yearly mammogram. MRI is known to give some false positive results which mean more test and/or biopsies for the patient. Thus, although breast MRI is useful for women at high risk, it is rarely recommended as a screening test for women at average risk of breast cancer. Also, breast MRI does not show calcium deposits, known as micro-calcifications which can be a sign of breast cancer.

Gut dysbiosis induced by cardiac pressure overload enhances adverse cardiac remodeling in a T cell-dependent manner

Despite the existing association of gut dysbiosis and T cell inflammation in heart failure (HF), whether and how gut microbes contribute to T cell immune responses, cardiac fibrosis and dysfunction in HF remains largely unexplored. Our objective was to investigate whether gut dysbiosis is induced by cardiac pressure overload, and its effect in T cell activation, adverse cardiac remodeling, and cardiac dysfunction. We used 16S rRNA sequencing of fecal samples and discovered that cardiac pressure overload-induced by transverse aortic constriction (TAC) results in gut dysbiosis, characterized by a reduction of tryptophan and short-chain fatty acids producing bacteria in WT mice, but not in T cell-deficient mice (Tcra^-/- ) mice. These changes did not result in T cell activation in the gut or gut barrier disruption. Strikingly, microbiota depletion in WT mice resulted in decreased heart T cell infiltration, decreased cardiac fibrosis, and protection from systolic dysfunction in response to TAC. Spontaneous reconstitution of the microbiota partially reversed these effects. We observed decreased cardiac expression of the Aryl hydrocarbon receptor (AhR) and enzymes associated with tryptophan metabolism in WT mice, but not in Tcra^-/- mice, or in mice depleted of the microbiota. These findings demonstrate that cardiac pressure overload induced gut dysbiosis and T cell immune responses contribute to adverse cardiac remodeling, and identify the potential contribution of tryptophan metabolites and the AhR to protection from adverse cardiac remodeling and systolic dysfunction in HF.

Nanoformulations for Ocular Delivery of Drugs - A Patent Perspective

Efficient delivery of ocular therapeutics with improved efficacy, enhanced bioavailability, and acceptable patient compliance presents unique challenges. This can be attributed to the presence of protective mechanisms, physicobiological barriers, and structural obstacles in the eye. Nanotherapeutic interventions have been explored extensively over the past few years to overcome these limitations. The present review focusses on the nanoformulations developed for the diagnosis and treatment of various ocular diseases besides providing an in-depth insight into the patents reported for the same.

ClinVar: improvements to accessing data

ClinVar is a freely available, public archive of human genetic variants and interpretations of their relationships to diseases and other conditions, maintained at the National Institutes of Health (NIH). Submitted interpretations of variants are aggregated and made available on the ClinVar website (https://www.ncbi.nlm.nih.gov/clinvar/), and as downloadable files via FTP and through programmatic tools such as NCBI's E-utilities. The default view on the ClinVar website, the Variation page, was recently redesigned. The new layout includes several new sections that make it easier to find submitted data as well as summary data such as all diseases and citations reported for the variant. The new design also better represents more complex data such as haplotypes and genotypes, as well as variants that are in ClinVar as part of a haplotype or genotype but have no interpretation for the single variant. ClinVar's variant-centric XML had its production release in April 2019. The ClinVar website and E-utilities both have been updated to support the VCV (variation in ClinVar) accession numbers found in the variant-centric XML file. ClinVar's search engine has been fine-tuned for improved retrieval of search results.

Linker-Regulated H2S Release from Aromatic Peptide Amphiphile Hydrogels

Controlled release is an essential requirement for delivery of hydrogen sulfide (H₂S) because of its reactive nature, short half-life in biological fluids, and toxicity at high concentrations. In this context, H₂S delivery via hydrogels may be beneficial as they can deliver H₂S locally at the site of interest. Herein, we employed hydrogels based on aromatic peptide amphiphiles (APAs) with tunable mechanical properties to modulate the rates of H₂S release. The APAs contained an aromatic S-aroylthiooxime (SATO) H₂S donor attached with a linker to a short IAVEEE hexapeptide. Linker units included carbonyl, substituted O-methylenes, alkenyl, and alkyl segments with the goal of evaluating the role of linker structure on self-assembly, capacity for hydrogelation, and H₂S release rate. We studied each peptide by transmission electron microscopy, circular dichroism spectroscopy, and rheology, and we measured H₂S release rates from each gel, triggering SATO decomposition and release of H₂S by addition of cysteine (Cys). Using an H₂S-selective electrode probe as well as a turn-on fluorescent H₂S probe in the presence of H9C2 cardiomyocytes, we found that the rate of H₂S release from the hydrogels depended on the rate of Cys penetration into the nanofiber core with stiffer gels showing longer overall release.

The Benefits of Macromolecular/Supramolecular Approaches in Hydrogen Sulfide Delivery: A Review of Polymeric and Self-Assembled Hydrogen Sulfide Donors

Significance: Cell homeostasis and redox balance are regulated in part by hydrogen sulfide (H2S), a gaseous signaling molecule known as a gasotransmitter. Given its biological roles, H2S has promising therapeutic potential, but controlled delivery of this reactive and hazardous gas is challenging due to its promiscuity, rapid diffusivity, and toxicity at high doses. Macromolecular and supramolecular drug delivery systems are vital for the effective delivery of many active pharmaceutical ingredients, and H2S stands to benefit greatly from the tunable physical, chemical, and pharmacokinetic properties of polymeric and/or self-assembled drug delivery systems. Recent Advances: Several types of H2S-releasing macro- and supramolecular materials have been developed in the past 5 years, and the field is expanding quickly. Slow-releasing polymers, polymer assemblies, polymer nano- and microparticles, and self-assembled hydrogels have enabled triggered, sustained, and/or localized H2S delivery, and many of these materials are more potent in biological assays than analogous small-molecule H2S donors. Critical Issues: H2S plays a role in a number of (patho)physiological processes, including redox balance, ion channel regulation, modulation of inducible nitric oxide synthase, angiogenesis, blood pressure regulation, and more. Chemical tools designed to (i) deliver H2S to study these processes, and (ii) exploit H2S signaling pathways for treatment of diseases require control over the timing, rate, duration, and location of release. Future Directions: Development of new material approaches for H2S delivery that enable long-term, triggered, localized, and/or targeted delivery of the gas will enable greater understanding of this vital signaling molecule and eventually expedite its clinical application.

Development of a calibration chamber to evaluate the performance of low-cost particulate matter sensors

Low-cost particulate matter (PM) air quality sensors are becoming widely available and are being increasingly deployed in ambient and home/workplace environments due to their low cost, compactness, and ability to provide more highly resolved spatiotemporal PM concentrations. However, the PM data from these sensors are often of questionable quality, and the sensors need to be characterized individually for the environmental conditions under which they will be making measurements. In this study, we designed and assessed a cost-effective (∼$700) calibration chamber capable of continuously providing a uniform PM concentration simultaneously to multiple low-cost PM sensors and robust calibration relationships that are independent of sensor position. The chamber was designed and evaluated with a Computational Fluid Dynamics (CFD) model and a rigorous experimental protocol. We then used this new chamber to calibrate 242 Plantower PMS 3003 sensors from two production lots (Batches I and II) with two aerosol types: ammonium nitrate (for Batches I and II) and alumina oxide (for Batch I). Our CFD models and experiments demonstrated that the chamber is capable of providing uniform PM concentration to 8 PM sensors at once within 6% error and with excellent reliability (intraclass correlation coefficient > 0.771). The study identified two malfunctioning sensors and showed that the remaining sensors had high linear correlations with a DustTrak monitor that was calibrated for each aerosol type (R2 > 0.978). Finally, the results revealed statistically significant differences between the responses of Batches I and II sensors to the same aerosol (P-value<0.001) and the Batch I sensors to the two different aerosol types (P-value<0.001). This chamber design and evaluation protocol can provide a useful tool for those interested in systematic laboratory characterization of low-cost PM sensors.

Hydrogen sulfide-releasing peptide hydrogel limits the development of intimal hyperplasia in human vein segments

Currently available interventions for vascular occlusive diseases suffer from high failure rates due to re-occlusive vascular wall adaptations, a process called intimal hyperplasia (IH). Naturally occurring hydrogen sulfide (H2S) works as a vasculoprotective gasotransmitter in vivo. However, given its reactive and hazardous nature, H2S is difficult to administer systemically. Here, we developed a hydrogel capable of localized slow release of precise amounts of H2S and tested its benefits on IH. The H2S-releasing hydrogel was prepared from a short peptide attached to an S-aroylthiooxime H2S donor. Upon dissolution in aqueous buffer, the peptide self-assembled into nanofibers, which formed a gel in the presence of calcium. This new hydrogel delivered H2S over the course of several hours, in contrast with fast-releasing NaHS. The H2S-releasing peptide/gel inhibited proliferation and migration of primary human vascular smooth muscle cells (VSMCs), while promoting proliferation and migration of human umbilical endothelial cells (ECs). Both NaHS and the H2S-releasing gel limited IH in human great saphenous vein segments obtained from vascular patients undergoing bypass surgery, with the H2S-releasing gel showing efficacy at a 5x lower dose than NaHS. These results suggest local perivascular H2S release as a new strategy to limit VSMC proliferation and IH while promoting EC proliferation, hence re-endothelialization. STATEMENT OF SIGNIFICANCE: Arterial occlusive disease is the leading cause of death in Western countries, yet current therapies suffer from high failure rates due to intimal hyperplasia (IH), a thickening of the vascular wall leading to secondary vessel occlusion. Hydrogen sulfide (H2S) is a gasotransmitter with vasculoprotective properties. Here we designed and synthesized a peptide-based H2S-releasing hydrogel and found that local application of the gel reduced IH in human vein segments obtained from patients undergoing bypass surgery. This work provides the first evidence of H2S efficacy against IH in human tissue, and the results show that the gel is more effective than NaHS, a common instantaneous H2S donor.

P04.19 Analysis of tumor immune microenvironment and immune checkpoint modulators across infantile and pediatric pilocytic astrocytomas to elucidate the role of immunotherapy in these tumors

BACKGROUND

Pilocytic astrocytomas are the most common central nervous system tumors in pediatric age-group. Although grade I, some of the cases show recurrence and progression, and few might not be amenable to surgery due to location or size, and hence have a less favorable prognosis. Drugs blocking immune check-point interactions such as those including programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) are now in clinical use for certain tumors. We performed this study to understand the potential candidature of pilocytic astrocytomas in infants and children for immunotherapy by analyzing the expression of immune checkpoint proteins and immune infiltrate, and correlating with clinical details, wherever possible.

MATERIALS AND METHODS

Cases with adequate tissue (2010–2017) diagnosed in pediatric age-group (<18 years) were retreived from the archives of Department of Pathology, AIIMS, New Delhi. Immunohistochemistry for PD-L1 (SP263, Ventana), CTLA-4, CD3, CD8, CD4 and CD68 was performed. Quantification of cytotoxic lymphocytes was done using digital imaging in the core of the tumor.

RESULTS

A total of 50 pilocytic astrocytomas were included, 14 of them were <3 years (infants), while 36 were of pediatric age-group (3–18 years). Overall, male preponderance was noted. Cerebellum was the most common location, followed by 4th venrticle, optic pathway, hypothalamus, cerebrum and thalamus. Almost all CD3 lymphocytes were cytotoxic T-lymphocyes (CD8 positive, CTLs). Helper T-lymphocyte infiltration was not seen. Median CTL density/mm3 was 13/mm3(Range:1–85/mm3). CTLA-4 was positive in 4 cases, positivity ranged from 1–4 cells/lpf. PD-L1 was found to be positive in 7 cases, and the positivity ranged from 1+ to 2+ in 1 to 5% of tumor cells. A median TAM (tumor associated macrophages) density of 44/hpf (range: 1–98/hpf) was noted. There was no correlation of CTL density with PD-L1 or CTLA-4 expression, and neither with TAM density. On correlation with clinical parameters, a higher density of CTLs and TAMs was noted in infants, and a higher proportion of cases revealed PD-L1 positivity, though not statistically significant. There was no correlation of TILs or TAMs with the tumor location.

CONCLUSION

Immune check point blockade using PD-(L)1 or CTLA4 inhibitors may not be a potential therapeutic option for unresectable or recurrent pilocytic astrocytomas, as low positivity rate as well as extremely low percentage of tumor/ immune cells found to be positive. However, alternate forms of immunotherapy might be helpful as most of the cases showed immune infiltrates and a high density of tumor-associated macrophages (TAMs). Large scale studies with larger numbers and longer follow-up periods including in-vitro and clinical studies are warranted for decoding the tumor immunogram.

P14.117 Cost efficient test algorithm for molecular subgrouping of medulloblastomas for day-to-day practice in resource limited countries

INTRODUCTION

Molecular classification of medulloblastomas(MB) is prognostically and therapeutically relevant and helps in better risk-stratification. Translation of this subgrouping to routine practice still remains a challenge. The most pathologist-accessible techniques for molecular subgrouping include immunohistochemistry(IHC), fluorescent in-situ hybridization(FISH) and Nanostring assay. Objectives:(1)Molecular subgrouping of MBs by IHC and FISH, and Nanostring Assay (2)To compare their efficacy against sequencing and DNA methylation, and cost for applicability in resource-constrained centers

METHODS

Ninety-five cases of MB with adequate tissue were included. Molecular subgrouping was performed by IHC for β-catenin, GAB1, YAP1, and p53; FISH for MYC amplification, and sequencing for CTNNB1, and by Nanostring Assay on the same set of MBs. Further, a subset of cases were subjected to 850k DNA methylation array.

RESULTS

IHC+FISH classified MBs into 15.8% WNT, 16.8% SHH, and 67.4% non-WNT/non-SHH subgroups; with MYC amplification identified in 20.3% cases of non-WNT/non-SHH. A single showed diffuse strong p53 positivity among the SHH subgroup. Nanostring successfully classified 91.5% MBs into 25.3% WNT, 17.2% SHH, 23% Group3 and 34.5% Group4. However, Nanostring assay failure was seen in eight cases, all of which were >8-years-old formalin-fixed paraffin-embedded tissue blocks. Concordant subgroup assignment was noted in 88.5% cases, while subgroup switching was seen in 11.5% cases. Both methods showed prognostic correlation. Among the 5 discrepant cases, which switched to WNT subgroup by Nanostring, only 2 were found to have CTNNB1 mutation. Methylation profiling performed on discordant cases revealed 1 out of 4 extra WNT identified by Nanostring to be WNT, others aligned with IHC subgroups; extra SHH by Nanostring turned out to be SHH by methylation.

CONCLUSIONS

Both IHC supplemented by FISH and Nanostring are robust methods for molecular subgrouping, albeit with few disadvantages. IHC cannot differentiate between Groups 3 and 4, while Nanostring cannot classify older-archived tumors, and is not available at most centres. WNT subgroup with the best prognosis is best detected by IHC or IHC followed by sequencing for confirmation. Nanostring Assay is better suitable to separate Group 3, the worst prognostic group from Group 4. Thus, both the methods complement each other and can be used in concert for high confidence allotment of molecular subgroups in clinical practice. The cost of IHC plus Nanostring will almost be the same as IHC plus FISH. We recommend a cost-efficient algorithmic approach using histopathological subtype and IHC as the first step followed by Nanostring or FISH, wherever suitable.

Abstract 220: Gut Microbiota Alterations Associate With T Cell Activation and Adverse Cardiac Remodeling in Response to Cardiac Pressure Overload

Background: The complex syndrome of heart failure (HF), a leading cause of morbidity and mortality affecting more than 24 million people worldwide, is recently becoming associated with alterations in gut microbiota, also known as gut dysbiosis, as well as with T cell mediated systemic inflammation and T cell infiltration in the heart. Specifically, certain bacteria promote T cell activation, and T cell activation contributes to adverse cardiac remodeling and cardiac dysfunction in HF. We hypothesize that gut dysbiosis modulates cardiac remodeling and function in a T cell-dependent manner.

Results: C57/BL6 mice were orally treated with a well-stablished wide spectrum antibiotic cocktail (ABX) and subjected to transverse aortic constriction (TAC), a model of non-ischemic HF. ABX was present during the duration of TAC (4 weeks), thus sterilizing the gut completely, or during 3 weeks before TAC followed by removal during the 4 weeks of TAC duration for spontaneous recovery of the gut microbiota (TAC-REC). The lack of gut microbiota showed a reduced T cell activation in the mediastinal lymph nodes and heart T cell infiltration, as well as cardiac fibrosis and cardiac hypertrophy were prevented in response to TAC. Nevertheless, gut dysbiosis induced by bacterial recolonization only partially recovered this phenotype. In addition, we sequenced 16S RNA to study the changes in bacterial populations in Sham, TAC, and TAC-REC. TAC induced changes in the gut microbiota compared to Sham surgery, which resulted in a higher relative abundance of several genera, such as Bacteroides, and lower relative abundance of Coprococcus, Lactobacillus and Bifidobacterium, these last two normally associated to an anti-inflammatory response. At the end of the experiment, bacterial recolonization in TAC-REC mice showed different relative bacterial abundance between TAC and TAC-REC, although there were no significant changes in diversity at 4 weeks post-TAC.

Conclusion: Collectively, our findings suggest that changes in gut microbiota constitution modify T cell activation and migration to the heart in the TAC model. Exploring the role of gut microbiota in modulating adverse cardiac remodeling and cardiac function can become an optimal therapeutic target to treat HF patients.