Preclinical Large Animal Porcine Models for Cardiac Regeneration and Its Clinical Translation: Role of hiPSC-Derived Cardiomyocytes

Myocardial Infarction (MI) occurs due to a blockage in the coronary artery resulting in ischemia and necrosis of cardiomyocytes in the left ventricular heart muscle. The dying cardiac tissue is replaced with fibrous scar tissue, causing a decrease in myocardial contractility and thus affecting the functional capacity of the myocardium. Treatments, such as stent placements, cardiac bypasses, or transplants are beneficial but with many limitations, and may decrease the overall life expectancy due to related complications. In recent years, with the advent of human induced pluripotent stem cells (hiPSCs), newer avenues using cell-based approaches for the treatment of MI have emerged as a potential for cardiac regeneration. While hiPSCs and their derived differentiated cells are promising candidates, their translatability for clinical applications has been hindered due to poor preclinical reproducibility. Various preclinical animal models for MI, ranging from mice to non-human primates, have been adopted in cardiovascular research to mimic MI in humans. Therefore, a comprehensive literature review was essential to elucidate the factors affecting the reproducibility and translatability of large animal models. In this review article, we have discussed different animal models available for studying stem-cell transplantation in cardiovascular applications, mainly focusing on the highly translatable porcine MI model.

Modulation of Mitochondrial Bioenergetics by Polydopamine Nanoparticles in Human iPSC-Derived Cardiomyocytes

Myocardial infarction (MI) leads to the formation of an akinetic scar on the heart muscle causing impairment in cardiac contractility and conductance, leading to cardiac remodeling and heart failure (HF). The current pharmacological approaches for attenuating MI are limited and often come with long-term adverse effects. Therefore, there is an urgent need to develop novel multimodal therapeutics capable of modulating cardiac activity without causing any major adverse effects. In the current study, we have demonstrated the applicability of polydopamine nanoparticles (PDA-NPs) as a bioactive agent that can enhance the contractility and beat propagation of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Treatment of hiPSC-CMs with PDA-NPs demonstrated accumulation of the latter into mitochondria and significantly enhanced time-dependent adenosine triphosphate (ATP) production in these cells, indicating improved mitochondrial bioenergetics. Furthermore, the effect of PDA-NPs on hiPSC-CM activity was evaluated by measuring calcium transients. Treatment with PDA-NPs increased the calcium cycling in hiPSC-CMs in a temporal manner. Our results demonstrated a significant reduction in peak amplitude, transient duration, time to peak, and transient decay time in the PDA-NPs-treated hiPSC-CMs as compared to untreated hiPSC-CMs. Additionally, treatment of isolated perfused rat heart ex vivo with PDA-NPs demonstrated cardiotonic effects on the heart and significantly improved the hemodynamic function, suggesting its potential for enhancing whole heart contractility. Lastly, the gene expression analysis data revealed that PDA-NPs significantly upregulated cardiac-specific genes (ACADM, MYL2, MYC, HCN1, MYL7, GJA5, and PDHA1) demonstrating the ability to modulate genetic expression of cardiomyocytes. Taken together, these findings suggest PDA-NPs capability as a versatile nanomaterial with potential uses in next-generation cardiovascular applications.

Assessment of mitophagy in human iPSC-derived cardiomyocytes

Defective mitophagy contributes to normal aging and various neurodegenerative and cardiovascular diseases. The newly developed methodologies to visualize and quantify mitophagy allow for additional progress in defining the pathophysiological significance of mitophagy in various model organisms. However, current knowledge regarding mitophagy relevant to human physiology is still limited. Model organisms such as mice might not be optimal models to recapitulate all the key aspects of human disease phenotypes. The development of the human-induced pluripotent stem cells (hiPSCs) may provide an exquisite approach to bridge the gap between animal mitophagy models and human physiology. To explore this premise, we take advantage of the pH-dependent fluorescent mitophagy reporter, mt-Keima, to assess mitophagy in hiPSCs and hiPSC-derived cardiomyocytes (hiPSC-CMs). We demonstrate that mt-Keima expression does not affect mitochondrial function or cardiomyocytes contractility. Comparison of hiPSCs and hiPSC-CMs during different stages of differentiation revealed significant variations in basal mitophagy. In addition, we have employed the mt-Keima hiPSC-CMs to analyze how mitophagy is altered under certain pathological conditions including treating the hiPSC-CMs with doxorubicin, a chemotherapeutic drug well known to cause life-threatening cardiotoxicity, and hypoxia that stimulates ischemia injury. We have further developed a chemical screening to identify compounds that modulate mitophagy in hiPSC-CMs. The ability to assess mitophagy in hiPSC-CMs suggests that the mt-Keima hiPSCs should be a valuable resource in determining the role mitophagy plays in human physiology and hiPSC-based disease models. The mt-Keima hiPSCs could prove a tremendous asset in the search for pharmacological interventions that promote mitophagy as a therapeutic target.Abbreviations: AAVS1: adeno-associated virus integration site 1; AKT/protein kinase B: AKT serine/threonine kinase; CAG promoter: cytomegalovirus early enhancer, chicken ACTB/β-actin promoter; CIS: cisplatin; CRISPR: clustered regularly interspaced short palindromic repeats; FACS: fluorescence-activated cell sorting; FCCP: carbonyl cyanide p-trifluoromethoxyphenylhydrazone; hiPSC: human induced pluripotent stem cell; hiPSC-CMs: human induced pluripotent stem cell-derived cardiomyocytes; ISO: isoproterenol; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PI3K: phosphoinositide 3-kinase; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RT: room temperature; SB: SBI-0206965; ULK1: unc-51 like autophagy activating kinase 1.

Abstract P1050: Activation Of Bk Ca Channel Increases Myocardial Infarction After Ischemia-Reperfusion Injury In Neonatal Hearts

Large-conductance calcium and voltage-activated potassium channels (BK Ca ) are heterogeneously expressed in a wide array of cells. In adult ventricular cardiomyocytes, activation of mitochondrial BK Ca channels is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, plasma membrane BK Ca channel activity has never been detected in adult ventricular cardiomyocytes. In this study, we report the presence of the BK Ca channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes. In neonatal cardiomyocyte (NCM), whole-cell potassium currents measured were sensitive to iberiotoxin (IbTx), suggesting the presence of BK Ca channels in the plasma membrane. Moreover, the open probability of single-channel recording decreased in presence of IbTx by 46+5% (n=10) and 32+5% (n=10) for rats and mice, respectively. Ex vivo studies with isolated neonatal hearts (p6) subjected to ischemia and post-conditioned with NS1619 during reoxygenation increased (58+3% as opposed to 48+5% for control, n>5 pups) the myocardial infarction whereas IbTx reduced (32+2%) the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia-reoxygenation (HR), whereas IbTx reduced TUNEL positive cells. In NCMs, activation of BK Ca channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BK Ca channels in the neonates protects the heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BK Ca channels in adults compared to neonatal heart could be attributed to their differential localization.

Abstract P2097: Hypochloremia Alters Cardiac Physiology After Myocardial Ischemia-Reperfusion Injury

Ischemic heart disease (IHD) is one of the leading causes of death related due to heart failure (HF). It is mainly characterized by impairment of heart contraction-relaxation (rhythmicity) and cardiac output. While a myriad of cellular processes is associated with IHD, one of the major cellular aspects strongly associated is the electrolyte and ionic imbalance. Serum sodium levels have been a well-established adverse prognostic marker for patients with chronic heart failure. Recent evidences have suggested that the lower serum chloride (hypochloremia, &lt90mM) is associated with increased mortality risk in patients with chronic HF independent of serum sodium levels. Serum chloride (Cl - ) is a major anion in physiology but its correlation to IHD has not been studied extensively. Hence, to better understand the role of hypochloremia in HF patients, we reviewed patients who received a left ventricular assist device (LVAD) placement at The Ohio State University Medical Center. Survival analysis demonstrated that patients with hypochloremia before LVAD placement had decreased survival at one year compared to patients with normal serum Cl - (p=0.0055). Moreover, our e x vivo studies with isolated rat hearts indicate hypochloremia aggravates myocardial infarction post ischemia-reperfusion (IR) injury. Hence, to elucidate Cl - mediated signaling mechanism we incorporated highly translational human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Our cellular studies demonstrate that physiological alteration of extracellular Cl - affects the function of beating hiPSC-CM. Hypochloremia significantly increases the beating rate by reducing the calcium cycling durations in hiPSC-CM. Studies are ongoing to determine the involvement of the chloride channel in maintaining chloride homeostasis. Taken together, our results for the first time establish the novel role and mechanism of chloride homeostasis in IR injury. These results will advance the need to search for effective therapeutic approaches to target novel Cl - channels in IHD.

Abstract P1035: Co-culturing Human Induced Pluripotent Stem Cell-derived Cardiomyocytes With Mesenchymal Stem Cells Promotes Their Maturation And Enhances Cardioprotection Under Hypoxic Stress

Introduction: Co-culturing human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hiCMs) with other stem/progenitor cells like bone-marrow mesenchymal stem cells (BM-MSCs) and endothelial progenitors has been shown to improve their survival post transplantation into ischemic hearts. Co-culturing with other cardiac cells has also shown to improve the maturation of hiCMs in vitro. However, the potential of co-culturing hiPSC-derived MSCs (hiMSCs) for hiCM maturation and cardioprotection has not been explored.

Hypothesis: We hypothesize that co-culturing of hiMSCs with hiCMs significantly alters the cells’ proteome, improves hiCM maturation, and enhances cardioprotection.

Results: hiCMs were co-cultured with hiMSCs for one week at a ratio of 3:1. To evaluate the effect of hiMSCs on hiCM maturation in the co-culture, changes in the hiCM function and gene expression were assessed via multi electrode array (MEA) analysis and qPCR, respectively. MEA analysis showed an increase in ADP50 and ADP90 in addition to improved response to cardiac drugs in hiCMs co-cultured with hiMSCs as compared to hiCM-only cultures, indicating improved maturation of hiCMs in the co-culture. Furthermore, gene expression analysis showed an increased expression of mature CM-associated genes (MYH7, TNNT2). When subjected to hypoxic stress (1% O 2 ), we also observed a significant decrease in the number of TUNEL positive cells in the co-cultures as compared to hiCM-only culture. Assessment of hiCM functionality via MEA analysis showed an improved cardioprotection in co-cultures as compared to the single cell-type cultures. Furthermore, proteomic analysis demonstrated increased expression of cardioprotective growth factors (GFs): HGF, VEGFA and IGFBP-1 in the conditioned medium of the co-cultured cells versus single cell-type cultures.

Conclusion: Overall, our results established that co-culturing hiCMs with hiMSCs improved cardioprotection via increased the expression of cardioprotective growth factors and enhanced the maturation of hiCMs in vitro.

Abstract P1044: A Drug-Like Activity Of Polydopamine Nanoparticles Mediates Cardiomyocyte Bio-Modulation And Maturation

Introduction: Bio-active nanomaterials are being extensively explored for various biomedical and tissue engineering applications. Polydopamine nanoparticles (PDA-NPs) is a self-assemble polymer derived from dopamine which has demonstrated anti-inflammatory potential by modulating immune cells. The use of PDA-NPs as bio-active nanomaterial for cardiac tissue repair/regeneration warrants further exploration.

Hypothesis: We hypothesize that the polydopamine nanoparticles could modulate cardiomyocyte activity due to the presence of catechol moieties and may alter the gene expression and promote maturation of cardiomyocyte.

Results: The PDA-NPs were fabricated by oxidative polymerization of dopamine monomers which resulted in formation of spherical nanoparticles. These nanoparticles were in the range of 100- 200 nm as evident from SEM and TEM imaging. The FTIR analysis of PDA-NPs revealed the characteristic peaks confirming the presence of quinone and catechol groups. These functional groups play important role in surface adhesion, thus imparting adhesive properties to PDA-NPs. The PDA-NPs were exposed to human iPSC-derived cardiomyocytes (HiPSC-CMs) and their real-time activity was monitored by using MEA. An instantaneous change in the beat period of cardiomyocytes was observed in a dose dependent manner. Moreover, a significant shortening in field potential duration was also seen, these finding suggest that the PDA-NPs stimulates the cardiomyocytes through catechol groups thereby exhibiting strong adrenergic effect. These finding demonstrates that PDA-NPs could significantly modulate the contractility of cardiomyocytes and could be used for enhancing cardiac contractility. Furthermore, prolonged incubation of PDA-NPs showed accumulation in the perinuclear region as revealed by fluorescence imaging. The influence of intracellular accumulation of PDA-NPs on gene expression was assessed by qRT-PCR. A significant increase in MYL2/MYL7 ratio, GJA5 and TNNI3 was noted, demonstrating the maturation of cardiomyocytes.

Conclusion: Overall, the treatment of hiPSC-CMs cardiomyocytes with PDA-NPs shows dual response, primarily by modulating the contractility in a dose dependent manner and secondary by promoting maturation.

Inhibition of BKCa channels protects neonatal hearts against myocardial ischemia and reperfusion injury

BK_Ca channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BK_Ca channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BK_Ca channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BK_Ca channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes, which protects the heart on inhibition but not activation. Furthermore, K⁺ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BK_Ca channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL-positive cells. In NCMs, activation of BK_Ca channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BK_Ca channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BK_Ca channels in adults compared to neonatal heart could be attributed to their differential localization.

Inhibition of BKCa channels protects neonatal hearts against myocardial ischemia and reperfusion injury.. [DOI: 10.1101/2021.11.02.466585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.

Abstract MP220: Identification And Functional Characterization Of Exosomal Bk Channels

Extracellular vesicles (EVs) specifically exosomes are important in mediating intracellular communications, and are capable of transferring genetic information between cells. Exosomes are used as a drug delivery vehicle to carry cargo for targeted therapy and have emerged as one of the most promising candidate for treating cardiovascular diseases. Exosomes get packaged inside the cell, excise out to the extracellular environment, and deliver the cargo to the target cells. However, the precise mechanism of how exosomes handle the differential ionic environment and the physiological role of their ion channels is not determined. Given that potassium (K + ) ions has the largest gradient, we focused on identifying the presence and physiological relevance of K+ channels in exosomes. Using the in silico approach, several ion channel candidates were identified, the most prominent ion channel being large conductance Ca 2+ and voltage-activated potassium channel (BK). To record BK in exosomes, we incorporated planar bilayers and a novel electrophysiology approach called near field electrophysiology (NFE), as the canonical patch-clamp methods are not feasible due to the size of EVs. Our NFE indicates a presence of K + channels in intact exosomes and 45% of them are sensitive to IbTX. Since IbTX specifically blocks, BK channels, we estimated 2 functional channels (single-channel conductance of 300 pS with 50% open probability) in a single exosome. Plasma-derived exosomes from BK +/+ and BK -/- mice subjected to differential K + gradient indicated that functional BK channels exist in exosomes, and help in maintaining their structural integrity. Furthermore, plasma derived exosomes from BK +/+ mice showed cardioprotection from ischemia-reperfusion injury whereas exosomes from BK -/- mice did not. Thus, the presence of BK determines the packaging as well as cardioprotective function of exosomes. Overall, the study for the first time indicate a presence of functional ion channel (BK) in exosomes which plays a role in protecting cells and heart against ischemia and reperfusion injury.

Adenosine deaminase modulates metabolic remodeling and orchestrates joint destruction in rheumatoid arthritis

Rheumatoid Arthritis (RA) is a chronic autoimmune disease associated with inflammation and joint remodeling. Adenosine deaminase (ADA), a risk factor in RA, degrades adenosine, an anti-inflammatory molecule, resulting in an inflammatory bias. We present an integrative analysis of clinical data, cytokines, serum metabolomics in RA patients and mechanistic studies on ADA-mediated effects on in vitro cell culture models. ADA activity differentiated patients into low and high ADA sets. The levels of the cytokines TNFα, IFNγ, IL-10, TGFβ and sRANKL were elevated in RA and more pronounced in high ADA sets. Serum metabolomic analysis shows altered metabolic pathways in RA which were distinct between low and high ADA sets. Comparative analysis with previous studies shows similar pathways are modulated by DMARDs and biologics. Random forest analysis distinguished RA from control by methyl-histidine and hydroxyisocaproic acid, while hexose-phosphate and fructose-6-phosphate distinguished high ADA from low ADA. The deregulated metabolic pathways of High ADA datasets significantly overlapped with high ADA expressing PBMCs GEO transcriptomics dataset. ADA induced the death of chondrocytes, synoviocyte proliferation, both inflammation in macrophages and their differentiation into osteoclasts and impaired differentiation of mesenchymal stem cells to osteoblasts and mineralization. PBMCs expressing elevated ADA had increased expression of cytokines and P2 receptors compared to synovial macrophages which has low expression of ADA. Our data demonstrates increased cytokine levels and distinct metabolic signatures of RA based on the ADA activity, suggests an important role for ADA in the pathophysiology of RA joints and as a potential marker and therapeutic target in RA patients.

In situ differentiation of human-induced pluripotent stem cells into functional cardiomyocytes on a coaxial PCL-gelatin nanofibrous scaffold

Human-induced pluripotent stem cells (hiPSCs) derived cardiomyocytes (hiPSC-CMs) have been explored for cardiac regeneration and repair as well as for the development of in vitro 3D cardiac tissue models. Existing protocols for cardiac differentiation of hiPSCs utilize a 2D culture system. However, the efficiency of hiPSC differentiation to cardiomyocytes in 3D culture systems has not been extensively explored. In the present study, we investigated the efficiency of cardiac differentiation of hiPSCs to functional cardiomyocytes on 3D nanofibrous scaffolds. Coaxial polycaprolactone (PCL)-gelatin fibrous scaffolds were fabricated by electrospinning and characterized using scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. hiPSCs were cultured and differentiated into functional cardiomyocytes on the nanofibrous scaffold and compared with 2D cultures. To assess the relative efficiencies of both the systems, SEM, immunofluorescence staining and gene expression analyses were performed. Contractions of differentiated cardiomyocytes were observed in 2D cultures after 2 weeks and in 3D cultures after 4 weeks. SEM analysis showed no significant differences in the morphology of cells differentiated on 2D versus 3D cultures. However, gene expression data showed significantly increased expression of cardiac progenitor genes (ISL-1, SIRPA) in 3D cultures and cardiomyocytes markers (TNNT, MHC6) in 2D cultures. In contrast, immunofluorescence staining showed no substantial differences in the expression of NKX-2.5 and α-sarcomeric actinin. Furthermore, uniform migration and distribution of the in situ differentiated cardiomyocytes was observed in the 3D fibrous scaffold. Overall, our study demonstrates that coaxial PCL-gelatin nanofibrous scaffolds can be used as a 3D culture platform for efficient differentiation of hiPSCs to functional cardiomyocytes.

Emerging Roles of Extracellular Vesicles Derived Non-Coding RNAs in the Cardiovascular System

Cardiovascular disease is the leading cause of morbidity and mortality all over the world. Emerging evidence emphasize the importance of extracellular vesicles (EVs) in the cell to cell communication in the cardiovascular system which is majorly mediated through non-coding RNA cargo. Advancement in sequencing technologies revealed a major proportion of human genome is composed of non-coding RNAs viz., miRNAs, lncRNAs, tRNAs, snoRNAs, piRNAs and rRNAs. However, our understanding of the role of ncRNAs-containing EVs in cardiovascular health and disease is still in its infancy. This book chapter provides a comprehensive update on our understanding on the role of EVs derived ncRNAs in the cardiovascular pathophysiology and their therapeutic potential.

Systems analysis of avascular necrosis of femoral head using integrative data analysis and literature mining delineates pathways associated with disease

Avascular necrosis of femoral head (AVNFH) is a debilitating disease, which affects the middle aged population. Though the disease is managed using bisphosphonate, it eventually leads to total hip replacement due to collapse of femoral head. Studies regarding the association of single nucleotide polymorphisms with AVNFH, transcriptomics, proteomics, metabolomics, biophysical, ultrastructural and histopathology have been carried out. Functional validation of SNPs was carried out using literature. An integrated systems analysis using the available datasets might help to gain further insights into the disease process. We have carried out an analysis of transcriptomic data from GEO-database, SNPs associated with AVNFH, proteomic and metabolomic data collected from literature. Based on deficiency of vitamins in AVNFH, an enzyme-cofactor network was generated. The datasets are analyzed using ClueGO and the genes are binned into pathways. Metabolomic datasets are analyzed using MetaboAnalyst. Centrality analysis using CytoNCA on the data sets showed cystathionine beta synthase and methylmalonyl-CoA-mutase to be common to 3 out of 4 datasets. Further, the genes common to at least two data sets were analyzed using DisGeNET, which showed their involvement with various diseases, most of which were risk factors associated with AVNFH. Our analysis shows elevated homocysteine, hypoxia, coagulation, Osteoclast differentiation and endochondral ossification as the major pathways associated with disease which correlated with histopathology, IHC, MRI, Micro-Raman spectroscopy etc. The analysis shows AVNFH to be a multi-systemic disease and provides molecular signatures that are characteristic to the disease process.

Scalable Biomimetic Coaxial Aligned Nanofiber Cardiac Patch: A Potential Model for "Clinical Trials in a Dish"

Recent advances in cardiac tissue engineering have shown that human induced-pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) cultured in a three-dimensional (3D) micro-environment exhibit superior physiological characteristics compared with their two-dimensional (2D) counterparts. These 3D cultured hiPSC-CMs have been used for drug testing as well as cardiac repair applications. However, the fabrication of a cardiac scaffold with optimal biomechanical properties and high biocompatibility remains a challenge. In our study, we fabricated an aligned polycaprolactone (PCL)-Gelatin coaxial nanofiber patch using electrospinning. The structural, chemical, and mechanical properties of the patch were assessed by scanning electron microscopy (SEM), immunocytochemistry (ICC), Fourier-transform infrared spectroscopy (FTIR)-spectroscopy, and tensile testing. hiPSC-CMs were cultured on the aligned coaxial patch for 2 weeks and their viability [lactate dehydrogenase (LDH assay)], morphology (SEM, ICC), and functionality [calcium cycling, multielectrode array (MEA)] were assessed. Furthermore, particle image velocimetry (PIV) and MEA were used to evaluate the cardiotoxicity and physiological functionality of the cells in response to cardiac drugs. Nanofibers patches were comprised of highly aligned core-shell fibers with an average diameter of 578 ± 184 nm. Acellular coaxial patches were significantly stiffer than gelatin alone with an ultimate tensile strength of 0.780 ± 0.098 MPa, but exhibited gelatin-like biocompatibility. Furthermore, hiPSC-CMs cultured on the surface of these aligned coaxial patches (3D cultures) were elongated and rod-shaped with well-organized sarcomeres, as observed by the expression of cardiac troponin-T and α-sarcomeric actinin. Additionally, hiPSC-CMs cultured on these coaxial patches formed a functional syncytium evidenced by the expression of connexin-43 (Cx-43) and synchronous calcium transients. Moreover, MEA analysis showed that the hiPSC-CMs cultured on aligned patches showed an improved response to cardiac drugs like Isoproterenol (ISO), Verapamil (VER), and E4031, compared to the corresponding 2D cultures. Overall, our results demonstrated that an aligned, coaxial 3D cardiac patch can be used for culturing of hiPSC-CMs. These biomimetic cardiac patches could further be used as a potential 3D in vitro model for "clinical trials in a dish" and for in vivo cardiac repair applications for treating myocardial infarction.

Abstract 396: 3d-Engineered Aligned Co-axial Nanofibrous Cardiac Patch for Drug Screening and Cardiac Repair Applications

Introduction: Recent studies have demonstrated the great potential of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for testing the efficacy of various cardiac drugs. Additionally, studies have shown that the hiPSC-CMs grown in a 3D environment express better physiological characteristics than 2D cultures. The convergence of polymeric cardiac patch technology with hiPSC-CMs has opened up innovative ways for generating biomimetic 3D cardiac tissues.

Hypothesis: The central hypothesis of this study was to develop a 3D cardiac tissue model for pharmacological testing of various cardiac drugs on a 3D nanofibrous aligned co-axial cardiac patch.

Methods: A co-axial (Co-A) PCL-gelatin aligned nanofibrous patch was fabricated using the electrospinning technique and its mechanical properties were assessed using Universal Test Machine. Then, the hiPSC-CMs were cultured on this Co-A patch for 2 weeks and the LDH assay was performed to determine the cell viability. The functionality of the cardiac patch was determined by an assessment of calcium cycling in hiPSC-CMs. Further, particle image velocimetry (PIV) and microelectrode array (MEA) was used to evaluate the physiological functionality of the cardiac patch in response to various cardiac drugs.

Results: Our studies showed that the mean diameter and thickness of aligned Co-A nanofibrous patch was 578±184 nm and 115±11 μm respectively, while its tensile strength was 0.780 ± 0.098 MPa. Further, confocal imaging confirmed the core-shell structure of the Co-A patches with a core diameter of 2.21 ± 0.50 μm. Additionally, The hiPSC-CMs cultured on these aligned Co-A patches showed an aligned morphology and expressed Troponin-T, GATA4, α-sarcomeric actinin, and connexin-43. The hiPSC-CMs seeded on a 3D scaffold showed efficient calcium cycling properties, which were similar to the hiPSC-CMs cultured in 2D scaffold. Furthermore, PIV and MEA analysis showed that hiPSC-CMs cultured in 2D and 3D showed a similar response to various cardiac drugs, isoproterenol, verapamil and E4031.

Conclusions: Overall, this study demonstrated a successful fabrication of aligned Co-A nanofibrous cardiac patch and its evaluation as a 3D cardiac tissue model in-vitro, which could be applied towards drug screening, toxicity studies and cardiac repair applications for ischemic heart disease.

Mouse embryonic stem cell-derived cardiomyocytes cease to beat following exposure to monochromatic light: association with increased ROS and loss of calcium transients

We earlier established the mouse embryonic stem (ES) cell "GS-2" line expressing enhanced green fluorescent protein (EGFP) and have been routinely using it to understand the molecular regulation of differentiation into cardiomyocytes. During such studies, we made a serendipitous discovery that functional cardiomyocytes derived from ES cells stopped beating when exposed to blue light. We observed a gradual cessation of contractility within a few minutes, regardless of wavelength (nm) ranges tested: blue (~420-495), green (~510-575), and red (~600-700), with green light manifesting the strongest impact. Following shifting of cultures back into the incubator (darkness), cardiac clusters regained beatings within a few hours. The observed light-induced contractility-inhibition effect was intrinsic to cardiomyocytes and not due to interference from other cell types. Also, this was not influenced by any physicochemical parameters or intracellular EGFP expression. Interestingly, the light-induced cardiomyocyte contractility inhibition was accompanied by increased intracellular reactive oxygen species (ROS), which could be abolished in the presence of N-acetylcysteine (ROS quencher). Besides, the increased intracardiomyocyte ROS levels were incidental to the inhibition of calcium transients and suppression of mitochondrial activity, both being essential for sarcomere function. To the best of our knowledge, ours is the first report to demonstrate the monochromatic light-mediated inhibition of contractions of cardiomyocytes with no apparent loss of cell viability and contractility. Our findings have implications in cardiac cell biology context in terms of 1) mechanistic insights into light impact on cardiomyocyte contraction, 2) potential use in laser beam-guided (cardiac) microsurgery, photo-optics-dependent medical diagnostics, 3) transient cessation of hearts during coronary artery bypass grafting, and 4) functional preservation of hearts for transplantation.

The Drosophila protein, Nausicaa, regulates lamellipodial actin dynamics in a Cortactin-dependent manner

Drosophila CG10915 is an uncharacterized protein coding gene with sequence similarity to human Cortactin-binding protein 2 (CTTNBP2) and Cortactin-binding protein 2 N-terminal-like (CTTNBP2NL). Here, we have named this gene Nausicaa (naus) and characterize it through a combination of quantitative live-cell total internal reflection fluorescence microscopy, electron microscopy, RNAi depletion and genetics. We found that Naus co-localizes with F-actin and Cortactin in the lamellipodia of Drosophila S2R+ and D25c2 cells and this localization is lost following Cortactin or Arp2/3 depletion or by mutations that disrupt a conserved proline patch found in its mammalian homologs. Using permeabilization activated reduction in fluorescence and fluorescence recovery after photobleaching, we find that depletion of Cortactin alters Naus dynamics leading to a decrease in its half-life. Furthermore, we discovered that Naus depletion in S2R+ cells led to a decrease in actin retrograde flow and a lamellipodia characterized by long, unbranched filaments. We demonstrate that these alterations to the dynamics and underlying actin architecture also affect D25c2 cell migration and decrease arborization in Drosophila neurons. We present the hypothesis that Naus functions to slow Cortactin's disassociation from Arp2/3 nucleated branch junctions, thereby increasing both branch nucleation and junction stability.

Traffic Priority Based Channel Assignment Technique for Critical Data Transmission in Wireless Body Area Network

In recent days, intelligent biomedical sensors and wearable devices are changing the healthcare industry by providing various heterogeneous vital signs of patients to the hospitals, caregivers, and clinicals. This collective form of monitoring sensor devices forms a very short-range Wireless Body Area Network (WBAN) and plays a key role in the data gathering process. If any sensor node in the network detects abnormal values that should be transmitted promptly via wireless medium with less delay. A single medium allows one-way delivery of a data packet, and it may not be sufficient to satisfy the high volume of communication demand between the sensor nodes in the network. In the same way, the packet prioritization does not guarantee the packet will get there on time and sometime it may cause priority conflicts among the nodes. It is only mean that the flow of delivery service handles that critical data packet before handling other data packets. However, unexploited time slots and bandwidth wastage will occur due to inefficient backoff management and collisions. To minimize the aforementioned issues, various backoff procedures, adaptive slot allocation mechanisms, priority-based medium access control protocols have been developed but suffer limitations in the context of providing priority-based channel access with less backoff conflicts and dedicated allocation of time slots for critical nodes in all cases. Based on these deliberations, a more effective Traffic Priority-based Channel Access Technique (TP-CAT) is proposed using IEEE 802.15.6 in order to minimize the transmission delay of critical data packet and solve conflicts among other priority nodes during the backoff phases. Firstly, a Low Threshold Criticality-based Adaptive Time slot Allocation algorithm (LT-CATA) is presented to decrease the priority slot conflicts between the low threshold data traffic from the same and different type of user priority nodes. Secondly, a High Threshold Criticality-based Adaptive Time slot Allocation algorithm (HT-CATA) is developed to reduce the priority slot conflicts between the high threshold data traffic from the same and different types of user priority nodes. Additionally, a novel Random Overlapping Backoff value Avoidance (ROBA) technique is introduced to eliminate the overlapping issue during the selection of random backoff value among the sensor nodes. Since, the proposed technique greatly reduced the channel access delay and transmission delay of critical data packet as well as other types of priority data packet. The Simulation results are verified in the CASTALIA 3.2 framework using omnet++ network simulater to relatively evaluate the performance metrics of the TP-CAT technique with state-of-the-art protocols. From the analysis of the results, it is evident that the TP-CAT technique provides better performance in terms of delay, energy consumption, and throughput in healthcare monitoring environments.

Observation of strong coupling through transmission modification of a cavity-coupled photonic crystal waveguide

We investigate strong coupling between a single quantum dot (QD) and photonic crystal cavity through transmission modification of an evanescently coupled waveguide. Strong coupling is observed through modification of both the cavity scattering spectrum and waveguide transmission. We achieve an overall Q of 5800 and an exciton-photon coupling strength of 21 GHz for this integrated cavity-waveguide structure. The transmission contrast for the bare cavity mode is measured to be 24%. These results represent important progress towards integrated cavity quantum electrodynamics using a planar photonic architecture.

The role of the basal ganglia in exploration in a neural model based on reinforcement learning

We present a computational model of basal ganglia as a key player in exploratory behavior. The model describes exploration of a virtual rat in a simulated water pool experiment. The virtual rat is trained using a reward-based or reinforcement learning paradigm which requires units with stochastic behavior for exploration of the system's state space. We model the Subthalamic Nucleus-Globus Pallidus externa (STN-GPe) segment of the basal ganglia as a pair of neuronal layers with oscillatory dynamics, exhibiting a variety of dynamic regimes such as chaos, traveling waves and clustering. Invoking the property of chaotic systems to explore state-space, we suggest that the complex exploratory dynamics of STN-GPe system in conjunction with dopamine-based reward signaling from the Substantia Nigra pars compacta (SNc) present the two key ingredients of a reinforcement learning system.

Injection site abscess due to Mycobacterium fortuitum: a case report

Injection abscess is an iatrogenic infection occurring as an isolated case or as cluster outbreak. These infections occur due to contaminated injectables or lapse in sterilisation protocol. While pathogens such as Pseudomonas, Klebsiella, E. coli, and S. aureus are the usual causative agents, unusual organisms such as mycobacteria, particularly the rapidly growing non-tuberculous mycobacteria (NTM) may cause the abscess. The chances of overlooking these organisms is high unless an acid fast bacilli (AFB) smear and culture is done on all aspirated pus specimens. We report a case of a three year old child who presented with a gluteal abscess following an intramuscular infection with an unknown preparation.

Evaluation of ParaHITf strip test for diagnosis of malarial infection

This study sought to determine whether dip stick strip test containing antibody for Plasmodium falciparum histidine rich protein-II (PfHRP-II) antigen could be used for identification of P. falciparum and P. vivax malaria in man. The results obtained were also compared with the results of standard microscopic examination. A total of 150 cases were included for the study. Fifty cases were non-febrile cases with no history of malaria acting as control group and the rest 100 cases were having fever and formed the test group. All the cases in the control group was found to be negative for both microscopic examination and strip test. In the test group, all samples that showed positive for P. falciparum by microscopy was also found to be positive for strip test. Whereas, all those samples that were positive for P. vivax in microscopic examination was found to be negative for strip test indicating species specificity of the strip test. In addition, two other cases that were negative for microscopic examination were found to be positive for the strip test. Statistical analysis was done to compare the validity of the results of strip test with that of the results of microscopic examination.