Fluorescent liposomal nanocarriers for targeted drug delivery in ischemic stroke therapy

Ischemic stroke causes acute CNS injury and long-term disability, with limited treatment options such as surgical clot removal or clot-busting drugs. Neuroprotective therapies are needed to protect vulnerable brain regions. The purinergic receptor P2X4 is activated during stroke and exacerbates post-stroke damage. The chemical compound 5-(3-Bromophenyl)-1,3-dihydro-2H-Benzofuro[3,2-e]-1,4-diazepin-2-one (5BDBD) inhibits P2X4 and has shown neuroprotective effects in rodents. However, it is difficult to formulate for systemic delivery to the CNS. The current manuscript reports for the first time, the synthesis and characterization of 5BDBD PEGylated liposomal formulations and evaluates their feasibility to treat stroke in a preclinical mice model. A PEGylated liposomal formulation of 5BDBD was synthesized and characterized, with encapsulation efficacy of >80%, and release over 48 hours. In vitro and in vivo experiments with Nile red encapsulation showed cytocompatibility and CNS infiltration of nanocarriers. Administered 4 or 28 hours after stroke onset, the nanoformulation provided significant neuroprotection, reducing infarct volume by ∼50% compared to controls. It outperformed orally-administered 5BDBD with a lower dose and shorter treatment duration, suggesting precise delivery by nanoformulation improves outcomes. The fluorescent nanoformulations may serve as a platform for delivering and tracking therapeutic agents for stroke treatment.

Functional mutation, splice, distribution, and divergence analysis of impactful genes associated with heart failure and other cardiovascular diseases

Cardiovascular disease (CVD) is caused by a multitude of complex and largely heritable conditions. Identifying key genes and understanding their susceptibility to CVD in the human genome can assist in early diagnosis and personalized treatment of the relevant patients. Heart failure (HF) is among those CVD phenotypes that has a high rate of mortality. In this study, we investigated genes primarily associated with HF and other CVDs. Achieving the goals of this study, we built a cohort of thirty-five consented patients, and sequenced their serum-based samples. We have generated and processed whole genome sequence (WGS) data, and performed functional mutation, splice, variant distribution, and divergence analysis to understand the relationships between each mutation type and its impact. Our variant and prevalence analysis found FLNA, CST3, LGALS3, and HBA1 linked to many enrichment pathways. Functional mutation analysis uncovered ACE, MME, LGALS3, NR3C2, PIK3C2A, CALD1, TEK, and TRPV1 to be notable and potentially significant genes. We discovered intron, 5' Flank, 3' UTR, and 3' Flank mutations to be the most common among HF and other CVD genes. Missense mutations were less common among HF and other CVD genes but had more of a functional impact. We reported HBA1, FADD, NPPC, ADRB2, ADBR1, MYH6, and PLN to be consequential based on our divergence analysis.

Transcriptomic analysis reveals novel age-independent immunomodulatory proteins as a mode of cerebroprotection in P2X4 receptor knockout mice after ischemic stroke

Identification of new potential drug target proteins and their plausible mechanisms for stroke treatment is critically needed. We previously showed that genetic deletion and short-term pharmacological inhibition of P2X4, a purinergic receptor for adenosine triphosphate (ATP), provides acute cerebroprotection. However, potential mechanisms remain unknown. Therefore, we employed RNA-Seq technology to identify the gene expression profiles and pathway analysis followed by qPCR validation of differentially expressed genes (DEGs). This analysis identified roles of DEGs in certain biological processes responsible for P2X4R-dependent cerebroprotection after stroke. We subjected both young and aged male and female global P2X4 receptor knock out (P2X4RKO) and littermate WT (WT) mice to ischemic stroke. After three days, mice were sacrificed, and total RNA was isolated using Trizol and subjected to RNA-Seq and NanoString-mediated qPCR. DESeq2, Gene Ontology (GO), and Ingenuity Pathway Analysis (IPA) were used to identify gene expression profiles and biological pathways. We found 2246 DEGs in P2X4R KO vs. WT tissue after stroke. Out of these DEGs, 1920 genes were downregulated and 325 genes were upregulated in P2X4R KO. GO/IPA analysis of the top 300 DEGs suggests an enrichment of inflammation and extracellular matrix component genes. qPCR validation of the top 30 DEGs revealed downregulation of two common age-independent genes in P2X4R KO mice: Interleukin-6 (Il-6), an inflammatory cytokine, and Cytotoxic T Lymphocyte-Associated Protein 2 alpha (Ctla2a), an immunosuppressive factor. These data suggest that P2X4R-mediated cerebroprotection after stroke is initiated by attenuation of immune modulatory pathways in both young and aged mice of both sexes.

Alicyclic Ring Size Variation of 4-Phenyl-2-naphthoic Acid Derivatives as P2Y14 Receptor Antagonists

P2Y14 receptor (P2Y14R) is activated by extracellular UDP-glucose, a damage-associated molecular pattern that promotes inflammation in the kidney, lung, fat tissue, and elsewhere. Thus, selective P2Y14R antagonists are potentially useful for inflammatory and metabolic diseases. The piperidine ring size of potent, competitive P2Y14R antagonist (4-phenyl-2-naphthoic acid derivative) PPTN 1 was varied from 4- to 8-membered rings, with bridging/functional substitution. Conformationally and sterically modified isosteres included N-containing spirocyclic (6-9), fused (11-13), and bridged (14, 15) or large (16-20) ring systems, either saturated or containing alkene or hydroxy/methoxy groups. The alicyclic amines displayed structural preference. An α-hydroxyl group increased the affinity of 4-(4-((1R,5S,6r)-6-hydroxy-3-azabicyclo[3.1.1]heptan-6-yl)phenyl)-7-(4-(trifluoromethyl)phenyl)-2-naphthoic acid 15 (MRS4833) compared to 14 by 89-fold. 15 but not its double prodrug 50 reduced airway eosinophilia in a protease-mediated asthma model, and orally administered 15 and prodrugs reversed chronic neuropathic pain (mouse CCI model). Thus, we identified novel drug leads having in vivo efficacy.

Cardiac and noncardiac biomarkers in patients undergoing anthracycline chemotherapy - a prospective analysis

BACKGROUND

Biomarkers represent a potential tool to identify individuals at risk for anthracycline-induced cardiotoxicity (AICT) prior to symptom onset or left ventricular dysfunction.

METHODS

This study examined the levels of cardiac and noncardiac biomarkers before, after the last dose of, and 3-6 months after completion of doxorubicin chemotherapy. Cardiac biomarkers included 5th generation high-sensitivity cardiac troponin T (cTnT), N-terminal pro-brain natriuretic peptide, growth/differentiation factor-15 (GDF-15), and soluble suppression of tumorigenesis-2 (sST2). Noncardiac biomarkers included activated caspase-1 (CASP-1), activated caspase-3, C-reactive protein, tumor necrosis factor-α, myeloperoxidase (MPO), galectin-3, and 8-hydroxy-2'-deoxyguanosine. Echocardiographic data (LVEF and LVGLS) were obtained at pre- and post-chemotherapy. Subanalysis examined interval changes in biomarkers among high (cumulative doxorubicin dose ≥ 250 mg/m²) and low exposure groups.

RESULTS

The cardiac biomarkers cTnT, GDF-15, and sST2 and the noncardiac biomarkers CASP-1 and MPO demonstrated significant changes over time. cTnT and GDF-15 levels increased after anthracycline exposure, while CASP-1 and MPO decreased significantly. Subanalysis by cumulative dose did not demonstrate a larger increase in any biomarker in the high-dose group.

CONCLUSIONS

The results identify biomarkers with significant interval changes in response to anthracycline therapy. Further research is needed to understand the clinical utility of these novel biomarkers.

Transcriptomic analysis reveals novel age-independent immunomodulatory proteins as a mode of cerebroprotection in P2X4R KO mice after ischemic stroke

Identification of new potential drug target proteins and their plausible mechanisms for stroke treatment is critically needed. We previously showed that genetic deletion and short-term pharmacological inhibition of P2X4R, a purinergic receptor for adenosine triphosphate ATP, provides acute cerebroprotection. However, potential mechanisms remain unknown. Therefore, we employed RNA-seq technology to identify the gene expression profiles, pathway analysis, and qPCR validation of differentially expressed genes (DEGs). This analysis identified roles of DEGs in certain biological processes responsible for P2X4R-dependent cerebroprotection after stroke. We subjected both young and aged male and female global P2X4 KO and littermate WT mice to ischemic stroke. After 3 days, mice were sacrificed, total RNA was isolated using Trizol, and subjected to RNA-seq and Nanostring-mediated qPCR. DESeq2, Gene Ontology (GO), and Ingenuity Pathway Analysis (IPA) were used to identify mRNA transcript expression profiles and biological pathways. We found 2246 DEGs in P2X4R KO vs WT tissue after stroke. Out of these DEGs, 1920 gene were downregulated, and 325 genes were upregulated in KO. GO/IPA analysis of the top 300 DEGs suggests an enrichment of inflammation and extracellular matrix component genes. qPCR validation of the top 30 DEGs revealed downregulation of two common age-independent genes in P2X4R KO mice: Interleukin-6 ( IL-6) , an inflammatory cytokine, and Cytotoxic T Lymphocyte-Associated Protein 2 alpha ( Ctla2a ), an immunosuppressive factor. These data suggest that P2X4R-mediated cerebroprotection after stroke is initiated by attenuation of immune modulatory pathways in both young and aged mice of both sexes.

Abstract TMP120: Transcriptomic Analysis Reveals Common Age Independent Immunomodulatory Proteins As A Mode Of Neuroprotection In P2X4R KO Mice After Ischemic Stroke

Background and Purpose: Identification of a new potential drug target protein and their plausible mechanism for stroke treatment is critically needed. We earlier showed that genetic deletion as well as short term pharmacological inhibition of P2X4R, a purinergic receptor for adenosine triphosphate ATP, provides acute neuroprotection and thus can be potential drug targets to treat ischemic stroke. However, potential mechanisms remain unknown. Therefore, in this study, we employed RNA-seq technology to identify the gene expression profiles, pathways analysis and qPCR validation of differentially expressed genes (DEGs). This analysis will identify role of those DEGs in certain biological processes responsible for P2X4R dependent neuroprotection after stroke.

Methods: We subjected young (8-12 weeks-old n= 4/group), and aged (12-18-month-old; n=8/group) male and female Global P2X4 KO and littermate WT mice to right middle cerebral artery occlusion MCAo for 60 min followed by 3 day of reperfusion. After 3 days, mice were sacrificed and prefrontal cortex tissue was isolated to extract total RNA using Trizol and used for RNA-seq sample preparations as well as for validation by Nanostring mediated qPCR technique. DESeq2 and Gene Ontology (GO) and /or Ingenuity Pathway Analysis (IPA) were used to identify mRNA transcript expression profiles and biological pathway. qPCR was analyzed with nSolver Data Analysis Support system.

Results: We found 2246 DEGs in P2X4R KO vs WT tissue after stroke. Out of these DEGs 1920 gene were downregulated and 325 genes were upregulated in KO. GO/IPA analysis of top 300 DEGs suggests an enrichment of ion channel transport system, inflammation and extracellular matrix component genes. QPCR validation of top 30 DEGs revealed down regulation of two common age independent genes: Lnterleukin-6 ( IL-6) , an inflammatory cytokine and Cytotoxic T Lymphocyte-Associated Protein 2 alpha ( Ctla2a ), an immunosuppressive factor KO group.

Conclusion: This data suggests P2X4R mediated neuroprotection after stroke is brought by attenuation of immune modulatory pathways in both young and aged mice of both sexes. Future studies will delineate the detailed role of IL-6 and Ctla2a in P2X4R mediated neuroprotection mechanisms after stroke.

Abstract 41: Synthesis And Pharmacological Validation Of Novel Neuroprotective Purinergic Receptor P2X4 Antagonists For The Treatment Of Ischemic Stroke

Background and Purpose: Identification of a novel treatment for ischemic stroke is urgently needed. We previously showed that genetic deletion as well as short term pharmacological inhibition of P2X4R, a purinergic receptor for adenosine triphosphate ATP, provides acute neuroprotection and thus can be potential drug targets to treat ischemic stroke. Here we synthesized and pharmacologically validated those experimental drugs for the treatment of ischemic stroke.

Methods: We first performed the P2X4 receptor structure activity (SAR) relationship based on known heterocyclic antagonist P2X4 antagonists including NP-1815-PX Following extensive modification of the reported synthetic route, we synthesized several analogues that maintained or enhanced antagonist affinity. We used [Ca 2+ ] i influx assay in P2X4R overexpressing human HEK cells to identify potent and specific P2X4R antagonist. Two most potent leads (MRS4719 and 4596 given subcutaneously for 3 days post stroke) were then tested for their neuroprotective activity using middle cerebral artery occlusion (MCAo) model of ischemic stroke (60 min MCAo followed by 3 days of reperfusion) using both sexes of young and aged mice. MRS4719 was also tested in human primary monocyte derived macrophage obtained from the blood of de-identified aged healthy subjects (55±10 years).

Results: Analogues MRS 4719 and MRS4596 were most potent at human (h) P2X4R (IC 50 0.503 and 1.38 μM, respectively), and were highly selective versus hP2X1R, hP2X2/3R, hP2X3R). Both MRS 4719 and MRS 4596 showed neuroprotective effects after 3 days of ischemic stroke in a dose dependent manner in young mice (8-12 weeks old). Optimal dose of MRS4719 (1.5 mg/kg/day) also significantly reduced infarct volume (59.6±5.3 vs. 27.47±10.23 mm 3 ; p<0.05) in middle-aged mice (11-12 months). MRS 4719 showed learning and memory enhancing activity when measured after 4 weeks of stroke. MRS 4719 inhibited ATP-induced [Ca 2+ ] i influx in primary human monocyte-derived macrophages, consistent with its blocking effect at endogenously expressed P2X4R.

Conclusions: This study indicates MRS4719 is a potent P2X4R antagonist and has translational potential for the treating of ischemic stroke across the age.

Structure-Activity Relationship and Neuroprotective Activity of 1,5-Dihydro-2H-naphtho[1,2-b][1,4]diazepine-2,4(3H)-diones as P2X4 Receptor Antagonists

We analyzed the P2X4 receptor structure-activity relationship of a known antagonist 5, a 1,5-dihydro-2H-naphtho[1,2-b][1,4]diazepine-2,4(3H)-dione. Following extensive modification of the reported synthetic route, 4-pyridyl 21u (MRS4719) and 6-methyl 22c (MRS4596) analogues were most potent at human (h) P2X4R (IC50 0.503 and 1.38 μM, respectively, and selective versus hP2X1R, hP2X2/3R, hP2X3R). Thus, the naphthalene 6-, but not 7-position was amenable to substitution, and an N-phenyl ring aza-scan identified 21u with 3-fold higher activity than 5. Compounds 21u and 22c showed neuroprotective and learning- and memory-enhancing activities in a mouse middle cerebral artery occlusion (MCAO) model of ischemic stroke, with potency of 21u > 22c. 21u dose-dependently reduced infarct volume and reduced brain atrophy at 3 and 35 days post-stroke, respectively. Relevant to clinical implication, 21u also reduced ATP-induced [Ca2+]i influx in primary human monocyte-derived macrophages. This study indicates the translational potential of P2X4R antagonists for treating ischemic stroke, including in aging populations.

Nexinhib20 Inhibits Neutrophil Adhesion and β2 Integrin Activation by Antagonizing Rac-1-Guanosine 5'-Triphosphate Interaction

Neutrophils are critical for mediating inflammatory responses. Inhibiting neutrophil recruitment is an attractive approach for preventing inflammatory injuries, including myocardial ischemia-reperfusion (I/R) injury, which exacerbates cardiomyocyte death after primary percutaneous coronary intervention in acute myocardial infarction. In this study, we found out that a neutrophil exocytosis inhibitor Nexinhib20 inhibits not only exocytosis but also neutrophil adhesion by limiting β2 integrin activation. Using a microfluidic chamber, we found that Nexinhib20 inhibited IL-8-induced β2 integrin-dependent human neutrophil adhesion under flow. Using a dynamic flow cytometry assay, we discovered that Nexinhib20 suppresses intracellular calcium flux and β2 integrin activation after IL-8 stimulation. Western blots of Ras-related C3 botulinum toxin substrate 1 (Rac-1)-GTP pull-down assays confirmed that Nexinhib20 inhibited Rac-1 activation in leukocytes. An in vitro competition assay showed that Nexinhib20 antagonized the binding of Rac-1 and GTP. Using a mouse model of myocardial I/R injury, Nexinhib20 administration after ischemia and before reperfusion significantly decreased neutrophil recruitment and infarct size. Our results highlight the translational potential of Nexinhib20 as a dual-functional neutrophil inhibitory drug to prevent myocardial I/R injury.

PLCβ2 Promotes VEGF-Induced Vascular Permeability

BACKGROUND

Regulation of vascular permeability is critical to maintaining tissue metabolic homeostasis. VEGF (vascular endothelial growth factor) is a key stimulus of vascular permeability in acute and chronic diseases including ischemia reperfusion injury, sepsis, and cancer. Identification of novel regulators of vascular permeability would allow for the development of effective targeted therapeutics for patients with unmet medical need.

METHODS

In vitro and in vivo models of VEGFA-induced vascular permeability, pathological permeability, quantitation of intracellular calcium release and cell entry, and phosphatidylinositol 4,5-bisphosphate levels were evaluated with and without modulation of PLC (phospholipase C) β2.

RESULTS

Global knock-out of PLCβ2 in mice resulted in blockade of VEGFA-induced vascular permeability in vivo and transendothelial permeability in primary lung endothelial cells. Further work in an immortalized human microvascular cell line modulated with stable knockdown of PLCβ2 recapitulated the observations in the mouse model and primary cell assays. Additionally, loss of PLCβ2 limited both intracellular release and extracellular entry of calcium following VEGF stimulation as well as reduced basal and VEGFA-stimulated levels of phosphatidylinositol 4,5-bisphosphate compared to control cells. Finally, loss of PLCβ2 in both a hyperoxia-induced lung permeability model and a cardiac ischemia:reperfusion model resulted in improved animal outcomes when compared with wild-type controls.

CONCLUSIONS

The results implicate PLCβ2 as a key positive regulator of VEGF-induced vascular permeability through regulation of both calcium flux and phosphatidylinositol 4,5-bisphosphate levels at the cellular level. Targeting of PLCβ2 in a therapeutic setting may provide a novel approach to regulating vascular permeability in patients.

RNA-seq driven expression and enrichment analysis to investigate CVD genes with associated phenotypes among high-risk heart failure patients

Background

Heart failure (HF) is one of the most common complications of cardiovascular diseases (CVDs) and among the leading causes of death in the US. Many other CVDs can lead to increased mortality as well. Investigating the genetic epidemiology and susceptibility to CVDs is a central focus of cardiology and biomedical life sciences. Several studies have explored expression of key CVD genes specially in HF, yet new targets and biomarkers for early diagnosis are still missing to support personalized treatment. Lack of gender-specific cardiac biomarker thresholds in men and women may be the reason for CVD underdiagnosis in women, and potentially increased morbidity and mortality as a result, or conversely, an overdiagnosis in men. In this context, it is important to analyze the expression and enrichment of genes with associated phenotypes and disease-causing variants among high-risk CVD populations.

Methods

We performed RNA sequencing focusing on key CVD genes with a great number of genetic associations to HF. Peripheral blood samples were collected from a broad age range of adult male and female CVD patients. These patients were clinically diagnosed with CVDs and CMS/HCC HF, as well as including cardiomyopathy, hypertension, obesity, diabetes, asthma, high cholesterol, hernia, chronic kidney, joint pain, dizziness and giddiness, osteopenia of multiple sites, chest pain, osteoarthritis, and other diseases.

Results

We report RNA-seq driven case–control study to analyze patterns of expression in genes and differentiating the pathways, which differ between healthy and diseased patients. Our in-depth gene expression and enrichment analysis of RNA-seq data from patients with mostly HF and other CVDs on differentially expressed genes and CVD annotated genes revealed 4,885 differentially expressed genes (DEGs) and regulation of 41 genes known for HF and 23 genes related to other CVDs, with 15 DEGs as significantly expressed including four genes already known (FLNA, CST3, LGALS3, and HBA1) for HF and CVDs with the enrichment of many pathways. Furthermore, gender and ethnic group specific analysis showed shared and unique genes between the genders, and among different races. Broadening the scope of the results in clinical settings, we have linked the CVD genes with ICD codes.

Conclusions

Many pathways were found to be enriched, and gender-specific analysis showed shared and unique genes between the genders. Additional testing of these genes may lead to the development of new clinical tools to improve diagnosis and prognosis of CVD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40246-021-00367-8.

Digital holographic deep learning of red blood cells for field-portable, rapid COVID-19 screening

Rapid screening of red blood cells for active infection of COVID-19 is presented using a compact and field-portable, 3D-printed shearing digital holographic microscope. Video holograms of thin blood smears are recorded, individual red blood cells are segmented for feature extraction, then a bi-directional long short-term memory network is used to classify between healthy and COVID positive red blood cells based on their spatiotemporal behavior. Individuals are then classified based on the simple majority of their cells' classifications. The proposed system may be beneficial for under-resourced healthcare systems. To the best of our knowledge, this is the first report of digital holographic microscopy for rapid screening of COVID-19.

Abstract P786: Effect of Age and Stroke on Purinergic Receptor P2x4 (p2x4r) Expression in Human Monocyte Subsets

Backgrounds: An acute ischemic stroke (AIS) triggers rapid infiltration of circulating immune cells in the brain. P2X4R, a receptor for adenosine triphosphate ATP, regulate activation of circulating monocytes after stroke injury. Over-stimulation of P2X4R contributes to ischemic injury. CD14 ++ CD16 – classical, CD14 ++ CD16 + intermediate, and CD14 + CD16 ++ non-classical monocytes are three primary subsets of monocytes. Alterations in activity of circulating monocyte subsets may independently predict pathogenesis of AIS, however, the role of P2X4R in the activation of these monocyte subsets is not known.

Methods: Consecutive AIS patients (60-90 years) undergoing endovascular clot retrieval and healthy control subjects both young (18-45 years) and aged (60-90 years) of both sexes were recruited and informed consent obtained. Flow cytometric analysis of whole blood derived monocytes at 0-2 days (acute, n=10), 3-7 days (subacute, n=9), and 65±20 days (chronic, n=7) after stroke onset were compared with healthy subjects (n=9-10/ age group).

Results: Both number of total monocyte counts and P2X4R intensity significantly increase with age when compared between healthy young and aged control (P<0.05). Total monocyte count progressively increased during recovery in AIS patient (P<0.05). No. of CD14 ++ CD16 + intermediate monocytes were significantly reduced after stroke ( p <0.05). Both CD14 ++ CD16 + intermediate, and CD14 + CD16 ++ non-classical monocytes showed a significant increased median fluorescent intensity (P<0.01) of P2X4R at subacute and chronic time after AIS.

Conclusions: P2X4R expression increases with age and after stroke. Disappearance of the CD14 + CD16 ++ non-classical monocyte subpopulation from circulation during stroke recovery suggests potential migration of these cells to the site of injury, consistent with their potential role in inflammation/phagocytosis. Increased P2X4R expression in intermediate and non-classical monocytes subpopulation suggest its specific role in selective activation of these monocytes subtype. Detailed molecular characterization of P2X4R response in intermediate and non-classical monocyte subpopulations may provide novel insights into P2X4R’s therapeutic potential during AIS.

Novel SARS-CoV-2 specific antibody and neutralization assays reveal wide range of humoral immune response during COVID-19

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n=115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.

Neuroprotective and neuro-rehabilitative effects of acute purinergic receptor P2X4 (P2X4R) blockade after ischemic stroke

Stroke remains a leading cause of disability in the United States. Despite recent advances, interventions to reduce damage and enhance recovery after stroke are lacking. P2X4R, a receptor for adenosine triphosphate (ATP), regulates activation of myeloid immune cells (infiltrating monocytes/macrophages and brain-resident microglia) after stroke injury. However, over-stimulation of P2X4Rs due to excessive ATP release from dying or damaged neuronal cells can contribute to ischemic injury. Therefore, we pharmacologically inhibited P2X4R to limit the over-stimulated myeloid cell immune response and improve both acute and chronic stroke recovery. We subjected 8-12-week-old male and female wild type mice to a 60 min right middle cerebral artery occlusion (MCAo) followed by 3 or 30 days of reperfusion. We performed histological, RNA sequencing, behavioral (sensorimotor, anxiety, and depressive), and biochemical (Evans blue dye extravasation, western blot, quantitative PCR, and flow cytometry) analyses to determine the acute (3 days after MCAo) and chronic (30 days after MCAo) effects of P2X4R antagonist 5-BDBD (1 mg/kg P.O. daily x 3 days post 4 h of MCAo) treatment. 5-BDBD treatment significantly (p < .05) reduced infarct volume, neurological deficit (ND) score, levels of cytokine interleukin-1 beta (IL-1β) and blood brain barrier (BBB) permeability in the 3-day group. Chronically, 5-BDBD treatment also conferred progressive recovery (p < .05) of motor balance and coordination using a rotarod test, as well as reduced anxiety-like behavior over 30 days. Interestingly, depressive-type behavior was not observed in mice treated with 5-BDBD for 3 days. In addition, flow cytometric analysis revealed that 5-BDBD treatment decreased the total number of infiltrated leukocytes, and among those infiltrated leukocytes, pro-inflammatory cells of myeloid origin were specifically reduced. 5-BDBD treatment reduced the cell surface expression of P2X4R in flow cytometry-sorted monocytes and microglia without reducing the total P2X4R level in brain tissue. In summary, acute P2X4R inhibition protects against ischemic injury at both acute and chronic time-points after stroke. Reduced numbers of infiltrating pro-inflammatory myeloid cells, decreased surface P2X4R expression, and reduced BBB disruption are likely its mechanism of neuroprotection and neuro-rehabilitation.

Prevention and rescue of cardiac dysfunction by methanocarba adenosine monophosphonate derivatives

Accumulating evidence supports a therapeutic role of purinergic signaling in cardiac diseases. Previously, efficacy of systemically infused MRS2339, a charged methanocarba derivative of 2-Cl-adenosine monophosphate, was demonstrated in animal models of heart failure. We now test the hypothesis that an uncharged adenine nucleoside phosphonate, suitable as an oral agent with a hydrolysis-resistant phospho moiety, can prevent the development of cardiac dysfunction in a post-infarction ischemic or pressure overload-induced heart failure model in mice. The diester-masked uncharged phosphonate MRS2978 was efficacious in preventing cardiac dysfunction with improved left ventricular (LV) fractional shortening when administered orally at the onset of ischemic or pressure overload-induced heart failure. MRS2925, the charged, unmasked MRS2978 analog, prevented heart dysfunction when infused subcutaneously but not by oral gavage. When administered orally or systemically, MRS2978 but not MRS2925 could also rescue established cardiac dysfunction in both ischemic and pressure overload heart failure models. The diester-masked phosphate MRS4074 was highly efficacious at preventing the development of dysfunction as well as in rescuing pressure overload-induced and ischemic heart failure. MRS2978 was orally bioavailable (57-75%) giving rise to MRS2925 as a minor metabolite in vivo, tested in rats. The data are consistent with a novel therapeutic role of adenine nucleoside phosphonates in systolic heart failure.

Debutant iOS app and gene-disease complexities in clinical genomics and precision medicine

Background

The last decade has seen a dramatic increase in the availability of scientific data, where human-related biological databases have grown not only in count but also in volume, posing unprecedented challenges in data storage, processing, analysis, exchange, and curation. Next generation sequencing (NGS) advancements have facilitated and accelerated the process of identifying genetic variations. Adopting NGS with Whole-Genome and RNA sequencing in a diagnostic context has the potential to improve disease-risk detection in support of precision medicine and drug discovery. Several bioinformatics pipelines have been developed to strengthen variant interpretation by efficiently processing and analyzing sequence data, whereas many published results show how genomics data can be proactively incorporated into medical practices and improve utilization of clinical information. To utilize the wealth of genomics and health, there is a crucial need to generate appropriate gene-disease annotation repositories accessed through modern technology.

Results

Our focus here is to create a comprehensive database with mobile access to actionable genes and classified diseases, considered the foundation for clinical genomics and precision medicine. We present a publicly available iOS app, PAS-Gen, which invites global users to freely download it on iPhone and iPad devices, quickly adopt its easy to use interface, and search for genes and related diseases. PAS-Gen was developed using Swift, XCODE, and PHP scripting that uses Web and MySQL database servers, which includes over 59,000 protein-coding and non-coding genes, and over 90,000 classified gene-disease associations. PAS-Gen is founded on the clinical and scientific premise that easier healthcare and genomics data sharing will accelerate future medical discoveries.

Conclusions

We present a cutting-edge gene-disease database with a smart phone application, integrating information on classified diseases and related genes. The PAS-Gen app will assist researchers, medical practitioners, and pharmacists by providing a broad and view of genes that may be implicated in the likelihood of developing certain diseases. This tool with accelerate users’ abilities to understand the genetic basis of human complex diseases and by assimilating genomic and phenotypic data will support future work to identify gene-specific designer drugs, target precise molecular fingerprints for tumors, suggest appropriate drug therapies, predict individual susceptibility to disease, and diagnose and treat rare illnesses.

Ca2+ Signaling in Cardiac Fibroblasts and Fibrosis-Associated Heart Diseases

Cardiac fibrosis is the excessive deposition of extracellular matrix proteins by cardiac fibroblasts and myofibroblasts, and is a hallmark feature of most heart diseases, including arrhythmia, hypertrophy, and heart failure. This maladaptive process occurs in response to a variety of stimuli, including myocardial injury, inflammation, and mechanical overload. There are multiple signaling pathways and various cell types that influence the fibrogenesis cascade. Fibroblasts and myofibroblasts are central effectors. Although it is clear that Ca2+ signaling plays a vital role in this pathological process, what contributes to Ca2+ signaling in fibroblasts and myofibroblasts is still not wholly understood, chiefly because of the large and diverse number of receptors, transporters, and ion channels that influence intracellular Ca2+ signaling. Intracellular Ca2+ signals are generated by Ca2+ release from intracellular Ca2+ stores and by Ca2+ entry through a multitude of Ca2+-permeable ion channels in the plasma membrane. Over the past decade, the transient receptor potential (TRP) channels have emerged as one of the most important families of ion channels mediating Ca2+ signaling in cardiac fibroblasts. TRP channels are a superfamily of non-voltage-gated, Ca2+-permeable non-selective cation channels. Their ability to respond to various stimulating cues makes TRP channels effective sensors of the many different pathophysiological events that stimulate cardiac fibrogenesis. This review focuses on the mechanisms of Ca2+ signaling in fibroblast differentiation and fibrosis-associated heart diseases and will highlight recent advances in the understanding of the roles that TRP and other Ca2+-permeable channels play in cardiac fibrosis.

100 Years of evolving gene-disease complexities and scientific debutants

It's been over 100 years since the word `gene' is around and progressively evolving in several scientific directions. Time-to-time technological advancements have heavily revolutionized the field of genomics, especially when it's about, e.g. triple code development, gene number proposition, genetic mapping, data banks, gene-disease maps, catalogs of human genes and genetic disorders, CRISPR/Cas9, big data and next generation sequencing, etc. In this manuscript, we present the progress of genomics from pea plant genetics to the human genome project and highlight the molecular, technical and computational developments. Studying genome and epigenome led to the fundamentals of development and progression of human diseases, which includes chromosomal, monogenic, multifactorial and mitochondrial diseases. World Health Organization has classified, standardized and maintained all human diseases, when many academic and commercial online systems are sharing information about genes and linking to associated diseases. To efficiently fathom the wealth of this biological data, there is a crucial need to generate appropriate gene annotation repositories and resources. Our focus has been how many gene-disease databases are available worldwide and which sources are authentic, timely updated and recommended for research and clinical purposes. In this manuscript, we have discussed and compared 43 such databases and bioinformatics applications, which enable users to connect, explore and, if possible, download gene-disease data.

Usefulness of Circulating Caspase-3 p17 and Caspase-1 p20 Peptides and Cardiac Troponin 1 During Cardioplegia to Gauge Myocardial Preservation

Evidence is accumulating that cardiac apoptosis occurs and contributes to myocyte cell death during myocardial ischemia. Cardioplegia, defined as the temporary cessation of cardiac activity during cardiac surgery, is a clinically controlled condition with myocardial ischemia and reperfusion. Our goal was to determine whether the apoptotic biomarker caspase-3 p17 is elevated in the coronary sinus (CS) during cardioplegia and if any elevations were reflected in the peripheral venous (PV) blood. Levels of the necrotic biomarker cardiac troponin I (cTnI) and the inflammatory marker caspase-1 p20 were also quantified in CS and PV. Blood was drawn before and at the end of cardioplegia in PV and CS and levels of p20, p17, and cTnI were measured. cTnI, p20, and p17 PV levels were significantly elevated compared with the control population before and at the end of cardioplegia. PV levels of all 3 markers increased after cardioplegia. CS levels were higher than PV levels for all 3 markers at both time points. Our data are consistent with the occurrence of cardiac apoptosis and inflammation during cardioplegia, in addition to necrosis. The heart-derived markers contributed to the peripheral levels and suggest that measurement of PV biomarker concentrations can be used to gauge cardiac preservation.

Abstract WP143: Acute Treatment With Purinergic Receptor P2X4 Inhibitors Show Neuroprotective and Neuro-Rehabilitation Potential in Ischemic Stroke

Introduction: Stroke remains a leading cause of disability in the United States. Despite recent advances, interventions to reduce damage and enhance recovery after stroke is lacking. Therefore, validating new drug targets is critical for stroke treatment. P2X4, a receptor for adenosine triphosphate ATP, regulate activation of myeloid immune cells (both infiltrating monocytes/macrophages and brain-resident microglia) after stroke injury. Over-stimulation of P2X4Rs, due to excessive ATP release from the dying or damaged neuronal cells, contributes to ischemic injury. In this study, we pharmacologically targeted P2X4R to control immune response of myeloid cells during acute stroke phase and studied recovery at acute or chronic time point after stroke.

Methods: We subjected 8-12 weeks old wild type mice of both sexes to 60 min right middle cerebral artery occlusion (MCAo) followed by 3 (acute) or 30 (chronic) days of reperfusion. We performed histological, behavioral (sensorimotor, anxiety and depressive), and flow cytometric analyses to determine the acute and chronic outcomes after P2X4R inhibitor 5-BDBD (1mg/kg P.O daily x3 days started after 4 hrs. of MCAo) treatment.

Results: Treatment with 5-BDBD for 3 days not only significantly (*P<0.05) reduced infarct volume (40.94 ± 7.512 N=7 vs 21.21 ± 7.372 N=11, unpaired t-test) and neurological deficit (ND) score at 3 days post-stroke but also showed a progressive recovery on motor and balance coordination using rotarod test (*P<0.05) during chronic recovery at 30 days. 5-BDBD treatments also improved (*P<0.01) anxiety like behavior during the chronic recovery. We did not see any effect on depression like behavior. Flow cytometric analysis reveals that 5-BDBD treatment significantly reduced (*P<0.05) total number of infiltrated leukocytes. Subsequent analysis revealed that among those infiltrated leukocytes the number of Ly6C +hi pro-inflammatory monocytes was reduced in 5-BDBD vs. vehicle treated mice.

Conclusions: Acute P2X4R inhibition protects against ischemic injury at both acute and chronic time point after stroke. Reduced number of infiltrated Ly6C +hi proinflammatory monocyte in 5-BDBD treated mice suggests its potential mechanism of neuroprotection after stroke.

MAV-clic: management, analysis, and visualization of clinical data

Objectives

Develop a multifunctional analytics platform for efficient management and analysis of healthcare data.

Materials and Methods

Management, Analysis, and Visualization of Clinical Data (MAV-clic) is a Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant framework based on the Butterfly Model. MAV-clic extracts, cleanses, and encrypts data then restructures and aggregates data in a deidentified format. A graphical user interface allows query, analysis, and visualization of clinical data.

Results

MAV-clic manages healthcare data for over 800 000 subjects at UConn Health. Three analytic capabilities of MAV-clic include: creating cohorts based on specific criteria; performing measurement analysis of subjects with a specific diagnosis and medication; and calculating measure outcomes of subjects over time.

Discussion

MAV-clic supports clinicians and healthcare analysts by efficiently stratifying subjects to understand specific scenarios and optimize decision making.

Conclusion

MAV-clic is founded on the scientific premise that to improve the quality and transition of healthcare, integrative platforms are necessary to analyze heterogeneous clinical, epidemiological, metabolomics, proteomics, and genomics data for precision medicine.

Use of integrated imaging and serum biomarker profiles to identify subclinical dysfunction in pediatric cancer patients treated with anthracyclines

BACKGROUND

Anthracycline induced cardiomyopathy is a major cause of mortality and morbidity among pediatric cancer survivors. It has been postulated that oxidative stress induction and inflammation may play a role in the pathogenesis of this process. Accordingly, the present study performed an assessment of biomarker profiles and functional imaging parameters focused upon potential early determinants of anthracycline induced cardiomyopathy.

METHODS

Patients (10-22 years) were prospectively enrolled between January 2013 and November 2014. Thirteen subjects completed the study and underwent serial cardiac magnetic resonance imaging and plasma biomarker profiling performed 24-48 h after the first anthracycline dose and at set dose intervals. In addition, we collected plasma samples from 62 healthy controls to examine normal plasma biomarker profiles.

RESULTS

Left ventricular ejection fraction (LVEF) decreased from 64.3 ± 6.2 at the first visit to 57.5 ± 3.3 (p = 0.004) 1 year after chemotherapy. A decline in longitudinal strain magnitude occurred at lower cumulative doses. A differential inflammatory/matrix signature emerged in anthracycline induced cardiomyopathy patients compared to normal including increased interleukin-8 and MMP levels. With longer periods of anthracycline dosing, MMP-7, a marker of macrophage proteolytic activation, increased by 165 ± 54% whereas interleukin-10 an anti-inflammatory marker decreased by 75 ± 13% (both p < 0.05). MMP7 correlated with time dependent changes in EF.

CONCLUSIONS

Asymptomatic pediatric patients exposed to anthracycline therapy develop abnormal strain parameters at lower cumulative doses when compared to changes in EF. A differential biomarker signature containing both inflammatory and matrix domains occur early in anthracycline treatment. Dynamic changes in these domains occur with increased anthracycline doses and progression to anthracycline induced cardiomyopathy. These findings provide potential prognostic and mechanistic insights into the natural history of anthracycline induced cardiomyopathy.

TRIAL REGISTRATION NUMBER

NCT03211520 Date of Registration February 13, 2017, retrospectively registered.

Deletion of the P2X4 receptor is neuroprotective acutely, but induces a depressive phenotype during recovery from ischemic stroke

INTRODUCTION

Acute ischemic injury leads to severe neuronal loss. One of the key mechanisms responsible for this effect is inflammation, which is characterized by the activation of myeloid cells, including resident microglia and infiltrating monocytes/macrophages. P2X4 receptors (P2X4Rs) present on these immune cells modulate the inflammatory response. For example, excessive release of adenosine triphosphate during acute ischemic stroke triggers stimulation of P2X4Rs, leading to myeloid cell activation and proliferation and further exacerbating post-ischemic inflammation. In contrast, during recovery P2X4Rs activation on microglia leads to the release of brain-derived neurotrophic factor (BDNF), which alleviate depression, maintain synaptic plasticity and hasten post-stroke behavioral recovery. Therefore, we hypothesized that deletion of the P2X4R specifically from myeloid cells would have differential effects on acute versus chronic recovery following stroke.

METHODS

We subjected global or myeloid-specific (MS) P2X4R knock-out (KO) mice and wild-type littermates of both sexes to right middle cerebral artery occlusion (60min). We performed histological, behavioral (sensorimotor and depressive), and biochemical (quantitative PCR and flow cytometry) analyses to determine the acute (three days after occlusion) and chronic (30days after occlusion) effects of receptor deletion.

RESULTS

Global P2X4R deletion led to reduced infarct size in both sexes. In MS P2X4R KO mice, only females showed reduced infarct size, an effect that did not change with ovariectomy. MS P2X4R KO mice of both sexes showed swift recovery from sensorimotor deficits during acute recovery but exhibited a more pronounced post-stroke depressive behavior phenotype that was independent of infarct size. Quantitative PCR analysis of whole cell lysate as well as flow-sorted myeloid cells from the perilesional cortex showed increased cellular interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) mRNA levels but reduced plasma levels of these cytokines in MS P2X4R KO mice after stroke. The expression levels of BDNF and other depression-associated genes were reduced in MS P2X4R KO mice after stroke.

CONCLUSIONS

P2X4R deletion protects against stroke acutely but predisposes to depression-like behavior chronically after stroke. Thus, a time-sensitive approach should be considered when targeting P2X4Rs after stroke.

Reduced in vivo toxicity of doxorubicin by encapsulation in cholesterol-containing self-assembled nanoparticles

We previously reported the development of an amphiphilic brush-like block copolymer composed of polynorbornene-cholesterol/polyethylene glycol (P(NBCh9-b-NBPEG)) that self-assembles in aqueous media to form long circulating nanostructures capable of encapsulating doxorubicin (DOX-NPs). Biodistribution studies showed that this formulation preferentially accumulates in tumor tissue with markedly reduced accumulation in the heart and other major organs. The aim of the current study was to evaluate the in vivo efficacy and toxicity of DOX containing self-assembled polymer nanoparticles in a mouse xenograft tumor model and compare its effects with the hydrochloride non-encapsulated form (free DOX). DOX-NPs significantly reduced the growth of tumors without inducing any apparent toxicity. Conversely, mice treated with free DOX exhibited significant weight loss, early toxic cardiomyopathy, acute toxic hepatopathy, reduced hematopoiesis and fatal toxicity. The improved safety profile of the polymeric DOX-NPs can be explained by the low circulating concentration of non-nanoparticle-associated drug as well as the reduced accumulation of DOX in non-target organs. These findings support the use of P(NBCh9-b-NBPEG) nanoparticles as delivery platforms for hydrophobic anticancer drugs intended to reduce the toxicity of conventional treatments.

Abstract WP270: Myeloid P2X4 Receptor Deletion Confers Neuroprotection in Females but not in Males After Experimental Stroke

Objective: Stroke is a sexually dimorphic disease. A growing body of literature from both clinical and experimental studies suggests that the outcomes after stroke differ in males versus females. Peripheral immune cells play a key role in stroke outcomes and also show sexual dimorphism. However, general immunosuppression has not shown an overall benefit in stroke patients. Therefore, identifying novel targets to improve stroke outcomes are urgently needed. P2X4 receptors (P2X4R) and P2X7 receptors (P2X7R) are the predominant subtypes expressed on immune and neural cells. The P2X7R and P2X4R interact and may physically associate with each other. Recent evidence demonstrates that P2X4R is necessary for the pro-inflammatory function of P2X7R. The goal of this study is to test the hypothesis that genetic deletion of P2X4R in myeloid immune cells impacts on stroke outcome and that such outcome differs in males vs. female mice.

Methods: P2X4R myeloid knockout mice and wild type littermates of both sexes (∼20-25g; C57BL/6), were randomized and subjected to right middle cerebral artery occlusion (MCAO-90min) followed by 3 days of reperfusion. At 72h after stroke mice were perfused and infarcts were quantified from 30μicron cut cresyl violet stained sections. The effect of myeloid P2X4R deletion on chronic functional recovery was assessed with neurological scores, corner test, Open field and the novel object recognition test. Data are expressed as mean±sem. ANOVA was performed and a P < .05 was set for statistical significance.

Results: A significant neuroprotective effect is seen in P2X4R KO compared to WT females (Cortex 36.1±1.5 vs 27.5±4.7; Striatum 67.4±1.5 vs 56.3±7.0; Total 34.8±1.6 vs 26.9±2.8. P<.05; n=7KO, 9WT). Ongoing studies in P2X4R KO ovariectomized females will determine if these sex specific effects are dependent on hormones (estrogen).

Conclusions: There is a sex-specific effect of immune cell P2X4R deletion. Myeloid specific deletion of P2X4R protects females from ischemia/reperfusion injury but has no salutary effect in males. This is the first study to demonstrate a deleterious effect of myeloid P2X4R on stroke outcomes. These initial findings implicate myeloid P2X4 as a novel therapeutic approach to improve ischemic outcomes in females.

Dsp rul: a spontaneous mouse mutation in desmoplakin as a model of Carvajal-Huerta syndrome

Studies of spontaneous mutations in mice have provided valuable disease models and important insights into the mechanisms of human disease. Ruffled (rul) is a new autosomal recessive mutation causing abnormal hair coat in mice. The rul allele arose spontaneously in the RB156Bnr/EiJ inbred mouse strain. In addition to an abnormal coat texture, we found diffuse epidermal blistering, abnormal electrocardiograms (ECGs), and ventricular fibrosis in mutant animals. Using high-throughput sequencing (HTS) we found a frameshift mutation at 38,288,978bp of chromosome 13 in the desmoplakin gene (Dsp). The predicted mutant protein is truncated at the c-terminus and missing the majority of the plakin repeat domain. The phenotypes found in Dsp(rul) mice closely model a rare human disorder, Carvajal-Huerta syndrome. Carvajal-Huerta syndrome (CHS) is a rare cardiocutaneous disorder that presents in humans with wooly hair, palmoplantar keratoderma and ventricular cardiomyopathy. CHS results from an autosomal recessive mutation on the 3' end of desmoplakin (DSP) truncating the full length protein. The Dsp(rul) mouse provides a new model to investigate the pathogenesis of CHS, as well as the underlying basic biology of the adhesion molecules coded by the desmosomal genes.

Cardiac P2X purinergic receptors as a new pathway for increasing Na⁺ entry in cardiac myocytes

P2X4 receptors (P2X4Rs) are ligand-gated ion channels capable of conducting cations such as Na(+). Endogenous cardiac P2X4R can mediate ATP-activated current in adult murine cardiomyocytes. In the present study, we tested the hypothesis that cardiac P2X receptors can induce Na(+) entry and modulate Na(+) handling. We further determined whether P2X receptor-induced stimulation of the Na(+)/Ca(2+) exchanger (NCX) has a role in modulating the cardiac contractile state. Changes in Na(+)-K(+)-ATPase current (Ip) and NCX current (INCX) after agonist stimulation were measured in ventricular myocytes of P2X4 transgenic mice using whole cell patch-clamp techniques. The agonist 2-methylthio-ATP (2-meSATP) increased peak Ip from a basal level of 0.52 ± 0.02 to 0.58 ± 0.03 pA/pF. 2-meSATP also increased the Ca(2+) entry mode of INCX (0.55 ± 0.09 pA/pF under control conditions vs. 0.82 ± 0.14 pA/pF with 2-meSATP) at a membrane potential of +50 mV. 2-meSATP shifted the reversal potential of INCX from -14 ± 2.3 to -25 ± 4.1 mV, causing an estimated intracellular Na(+) concentration increase of 1.28 ± 0.42 mM. These experimental results were closely mimicked by mathematical simulations based on previously established models. KB-R7943 or a structurally different agent preferentially opposing the Ca(2+) entry mode of NCX, YM-244769, could inhibit the 2-meSATP-induced increase in cell shortening in transgenic myocytes. Thus, the Ca(2+) entry mode of INCX participates in P2X agonist-stimulated contractions. In ventricular myocytes from wild-type mice, the P2X agonist could increase INCX, and KB-R7943 was able to inhibit the contractile effect of endogenous P2X4Rs, indicating a physiological role of these receptors in wild-type cells. The data demonstrate a novel Na(+) entry pathway through ligand-gated P2X4Rs in cardiomyocytes.

Novel protective role of endogenous cardiac myocyte P2X4 receptors in heart failure

BACKGROUND

Heart failure (HF), despite continuing progress, remains a leading cause of mortality and morbidity. P2X4 receptors (P2X4R) have emerged as potentially important molecules in regulating cardiac function and as potential targets for HF therapy. Transgenic P2X4R overexpression can protect against HF, but this does not explain the role of native cardiac P2X4R. Our goal is to define the physiological role of endogenous cardiac myocyte P2X4R under basal conditions and during HF induced by myocardial infarction or pressure overload.

METHODS AND RESULTS

Mice established with conditional cardiac-specific P2X4R knockout were subjected to left anterior descending coronary artery ligation-induced postinfarct or transverse aorta constriction-induced pressure overload HF. Knockout cardiac myocytes did not show P2X4R by immunoblotting or by any response to the P2X4R-specific allosteric enhancer ivermectin. Knockout hearts showed normal basal cardiac function but depressed contractile performance in postinfarct and pressure overload models of HF by in vivo echocardiography and ex vivo isolated working heart parameters. P2X4R coimmunoprecipitated and colocalized with nitric oxide synthase 3 (eNOS) in wild-type cardiac myocytes. Mice with cardiac-specific P2X4R overexpression had increased S-nitrosylation, cyclic GMP, NO formation, and were protected from postinfarct and pressure overload HF. Inhibitor of eNOS, L-N(5)-(1-iminoethyl)ornithine hydrochloride, blocked the salutary effect of cardiac P2X4R overexpression in postinfarct and pressure overload HF as did eNOS knockout.

CONCLUSIONS

This study establishes a new protective role for endogenous cardiac myocyte P2X4R in HF and is the first to demonstrate a physical interaction between the myocyte receptor and eNOS, a mediator of HF protection.

CD13 is essential for inflammatory trafficking and infarct healing following permanent coronary artery occlusion in mice

Aims

To determine the role of CD13 as an adhesion molecule in trafficking of inflammatory cells to the site of injury in vivo and its function in wound healing following myocardial infarction induced by permanent coronary artery occlusion.

Methods and results

Seven days post-permanent ligation, hearts from CD13 knockout (CD13^KO) mice showed significant reductions in cardiac function, suggesting impaired healing in the absence of CD13. Mechanistically, CD13^KO infarcts showed an increase in small, endothelial-lined luminal structures, but no increase in perfusion, arguing against an angiogenic defect in the absence of CD13. Cardiac myocytes of CD13^KO mice showed normal basal contractile function, eliminating myocyte dysfunction as a mechanism of adverse remodelling. Conversely, immunohistochemical and flow cytometric analysis of CD13^KO infarcts demonstrated a dramatic 65% reduction in infiltrating haematopoietic cells, including monocytes, macrophages, dendritic, and T cells, suggesting a critical role for CD13 adhesion in inflammatory trafficking. Accordingly, CD13^KO infarcts also contained fewer myofibroblasts, consistent with attenuation of fibroblast differentiation resulting from the reduced inflammation, leading to adverse remodelling.

Conclusion

In the ischaemic heart, while compensatory mechanisms apparently relieve potential angiogenic defects, CD13 is essential for proper trafficking of the inflammatory cells necessary to prime and sustain the reparative response, thus promoting optimal post-infarction healing.

Ischemic Conditioning and Atrial Fibrillation: Hope for a NewTherapy?

Atrial fibrillation (AF) is the most common sustained arrhythmia.It is accompanied by both structural and ion channel remodeling which underlie the propensity to perpetuate AF.The prevalence of AF is expected to increase as population ages and as more patients survival myocardial infarction. Despite pharmacological and nonpharmacological (such as ablation) therapies for AF, more effective therapy is needed. Ischemic or pharmacological conditioning offers a potential novel approach to patients with AF. This review will focus on the basic biology of ischemic pre- and postconditioning, patho-physiology of AF, potentially novel AF treatment approachs based on conditioning, and clinical situations that may be amenable to a conditioning strategy.

5'-Phosphate and 5'-phosphonate ester derivatives of (N)-methanocarba adenosine with in vivo cardioprotective activity

Activation of a cardiac myocyte P2X4 receptor protects against heart failure. 5'-Phosphonate and 5'-phosphate analogues of AMP containing a (N)-methanocarba (bicyclo[3.1.0]hexane) system could protect from heart failure by potentially activating this cardioprotective channel. Phosphoesters and phosphonodiesters were synthesized and administered in vivo via a miniosmotic pump in a mouse ischemic heart failure model and most significantly increased intact heart contractile function (echocardiography) compared to vehicle infusion. Several new thio and deuterated phosphate derivatives were protective in a calsequestrin (CSQ) overexpressing heart failure model. Diethyl (7, MRS4084) and diisopropyl (8, MRS4074) phosphotriesters were highly protective in the ischemic model. Substitution of 2-Cl with iodo reduced protection in the CSQ model. Diisopropyl ester 16 (MRS2978) of (1'S,2'R,3'S,4'R,5'S)-4'-(6-amino-2-chloropurin-9-yl)-2',3'-(dihydroxy)-1'-(phosphonoethylene)bicyclo[3.1.0]hexane was highly efficacious (CSQ), while lower homologue 1'-phosphonomethylene derivative 14 was inactive. Thus, we identified uncharged carbocyclic nucleotide analogues that represent potential candidates for the treatment of heart failure, suggesting this as a viable and structurally broad approach.

Cardiac P2X(4) receptors: targets in ischemia and heart failure?

Purinergic receptors have attracted growing interest as therapeutic targets. This perspective focuses on P2X(4) receptors as a new cardioprotective target in heart failure.

Elevated vascular endothelial growth factor receptor-2 abundance contributes to increased angiogenesis in vascular endothelial growth factor receptor-1-deficient mice

BACKGROUND

Vascular endothelial growth factor receptor-1 (VEGFR-1/Flt-1) is a potential therapeutic target for cardiovascular diseases, but its role in angiogenesis remains controversial. Whereas germline Vegfr-1(-/-) embryos die of abnormal vascular development in association with excessive endothelial differentiation, mice lacking only the kinase domain appear healthy.

METHODS AND RESULTS

We performed Cre-loxP-mediated knockout to abrogate the expression of all known VEGFR-1 functional domains in neonatal and adult mice and analyzed developmental, pathophysiological, and molecular consequences. VEGFR-1 deficiency promoted tip cell formation and endothelial cell proliferation and facilitated angiogenesis of blood vessels that matured and perfused properly. Vascular permeability was normal at the basal level but elevated in response to high doses of exogenous VEGF-A. In the postinfarct ischemic cardiomyopathy model, VEGFR-1 deficiency supported robust angiogenesis and protected against myocardial infarction. VEGFR-1 knockout led to abundant accumulation of VEGFR-2 at the protein level, increased VEGFR-2 tyrosine phosphorylation transiently, and enhanced serine phosphorylation of Akt and ERK. Interestingly, increased angiogenesis, tip cell formation, vascular permeability, VEGFR-2 accumulation, and Akt phosphorylation could be partially rescued or suppressed by one or more of the following manipulations, including injection of the VEGFR-2 selective inhibitor SU1498, anti-VEGF-A, or introduction of Vegfr-2(+/-) heterozygosity into Vegfr-1 somatic knockout mice.

CONCLUSIONS

Upregulation of VEGFR-2 abundance at the protein level contributes in part to increased angiogenesis in VEGFR-1-deficient mice.

OT1-02-12: Early Detection of Cardiotoxicity by Advanced Cardiac Imaging and a Novel Biomarker in Breast Cancer Patients Undergoing Chemotherapy

Background The survival rate of breast cancer patients has increased due to improvements in cancer treatment. However, many survivors develop irreversible or reversible cardiotoxicity associated with anthracycline or trastuzumab therapy, respectively. To detect cardiac damage, the currently accepted method is to measure left ventricular ejection fraction (LVEF) by echocardiography, which lacks the sensitivity to predict early cardiac dysfunction.

Early identification of cardiotoxicity is essential to cancer survivors, as development of cardiomyopathy carries a worse outcome independent of cancer prognosis. Currently, there are no accepted guidelines for the early detection of myocardial injury. The use of cardiac biomarkers and more sensitive echocardiographic techniques have expanded options for monitoring, but have yet to reach a consensus.

Hence, our study will evaluate the potential predictive value of novel cardiac biomarkers and advanced echocardiographic and cardiac magnetic resonance imaging (CMR) techniques to detect subclinical myocardial damage. Our findings may be applicable for monitoring new antineoplastic agents during food and drug administration (FDA) clinical trials.

Trial Design Prospective cohort study with internal control of 20 patients newly diagnosed with breast cancer. The trial will assess endpoints at baseline, 2 weeks after initiation of therapy, and 2 weeks and 6 months after chemotherapy completion.

1. Primary Endpoint

a. Decline in left ventricular ejection fraction assessed by CMR and 3D-echo not detected by conventional methods

b. Presence of either myocardial fibrosis or edema detected by CMR

c. Changes in myocardial deformation detected by echo or CMR strain

d. Increase in cardiac biomarkers (Serum caspase-3 p17 peptide, Troponin I, B-type natriuretic peptide) and possible correlation with imaging parameters

2. Secondary Endpoint

a. Development New York Heart Association class 1 to 4 symptoms

b. Decrease in LVEF of ≥5% to ≤50% with or without symptoms

Eligibility Criteria

Inclusion Criteria:

1. Newly diagnosed stage I, II, or III breast cancer

2. Age between 18 and 75 years old.

3. Treatment with trastuzumab or anthracycline-based chemotherapy

Exclusion Criteria:

1. History of cardiovascular disease

2. Pacemaker

3. History of mediastinal radiotherapy

4. Creatinine clearance &lt;30 ml/min

5. Serum bilirubin &gt;2.0 mg/dl, ALT and AST &gt; 100 U/1)

6. Hypertension, uncontrolled &gt;140/90

7. LVEF &lt;55% per 2-D echocardiogram

8. Claustrophobia

Specific Aims

1. Detect early myocardial injury.

2. Evaluate early predictors of left ventricular dysfunction.

3. Evaluate timing of monitoring during or post treatment

Statistical Method

This is a pilot study and 20 patients are required to reach statistical significance with 85% power. All values will be analyzed as mean±SD or n (%). Categorical indicators will be analyzed using nonparametric statistics such as Cochran's Q. Changes in imaging and biomarker parameters will be assessed using analysis of variance, while correlation between the two will be assessed using mixed models appropriate for binary outcome. Significance will be accepted at p ≤0.05 for all tests.

Present accrual and target accrual

Nine subjects are enrolled with a goal of 20.

Contact for people interested in trial:

1. Dr. Erick Avelar, eavelar@uchc.edu

2. Dr. Susan Tannenbaum, stannenbaum@uchc.edu

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT1-02-12.

Adenosine A3 receptor stimulation reduces muscle injury following physical trauma and is associated with alterations in the MMP/TIMP response

We have previously demonstrated that in response to traumatic injury in skeletal muscle, there is a dysregulation of the matrix metalloproteases (MMPs) and their inhibitors (TIMPs), a response hypothesized to interfere with proper skeletal muscle regeneration. Moreover, we have shown that pharmacological activation of the adenosine A(3) receptor by Cl-IBMECA in skeletal muscle can protect against ischemia-reperfusion and eccentric exercise injury. However, the mechanism by which Cl-IBMECA protects muscle tissue is poorly defined. This study evaluated the effects of Cl-IBMECA on MMP/TIMP expression in skeletal muscle and tested the hypothesis that adenosine A(3) receptor-stimulated protection of skeletal muscle following traumatic injury is associated with a blunting of MMPs involved in inflammatory processes and collagen degradation, and an increase in MMPs associated with extracellular matrix remodeling. Sixty C57BL/6J male mice were injected with Cl-IBMECA (n = 30) or a vehicle (n = 30), and Evans blue dye. Injury was induced by applying a cold steel probe (-79°C) to the tibialis anterior (TA) muscle for 10 s. TA muscles from uninjured and injured legs were collected 3, 10, and 24 h postinjury for analysis of muscle injury and MMP/TIMP mRNA and protein levels. Twenty-four hours postinjury, 56.8% of the fibers were damaged in vehicle-treated mice vs. 35.4% in Cl-IBMECA-treated mice (P = 0.02). Cl-IBMECA treatment reduced membrane type 1 (MT1)-MMP, MMP-3, MMP-9, and TIMP-1 mRNA expression 2- to 20-fold compared with vehicle-treated mice (P < 0.05). Cl-IBMECA decreased protein levels of latent/shed MT1-MMP 23-2,000%, respectively, 3-10 h postinjury. In Cl-IBMECA-treated mice, latent MMP-2 was decreased 20% 3 h postinjury, active MMP-3 was decreased 64% 3 h postinjury, and latent/active MMP-9 was decreased 417,631% 3 h postinjury and 20% 10 h postinjury. Protein levels of active MMP-2 and latent MMP-3 were increased 25% and 74% 3 h postinjury, respectively. The present study elucidates a new protective role of adenosine A(3) receptor stimulation in posttraumatic skeletal muscle injury.

Pharmacological and therapeutic effects of A3 adenosine receptor agonists

The A(3) adenosine receptor (A(3)AR) coupled to G(i) (inhibitory regulative guanine nucleotide-binding protein) mediates anti-inflammatory, anticancer and anti-ischemic protective effects. The receptor is overexpressed in inflammatory and cancer cells, while low expression is found in normal cells, rendering the A(3)AR as a potential therapeutic target. Highly selective A(3)AR agonists have been synthesized and molecular recognition in the binding site has been characterized. In this article, we summarize preclinical and clinical human studies that demonstrate that A(3)AR agonists induce specific anti-inflammatory and anticancer effects through a molecular mechanism that entails modulation of the Wnt and the NF-κB signal transduction pathways. At present, A(3)AR agonists are being developed for the treatment of inflammatory diseases, including rheumatoid arthritis (RA) and psoriasis; ophthalmic diseases such as dry eye syndrome and glaucoma; liver diseases such as hepatocellular carcinoma and hepatitis.

cPLA2 is protective against COX inhibitor-induced intestinal damage

Cytosolic phospholipase A(2) (cPLA(2)) is the rate-limiting enzyme responsible for the generation of prostaglandins (PGs), which are bioactive lipids that play critical roles in maintaining gastrointestinal (GI) homeostasis. There has been a long-standing association between administration of cyclooxygenase (COX) inhibitors and GI toxicity. GI injury is thought to be induced by suppressed production of GI-protective PGs as well as direct injury to enterocytes. The present study sought to determine how pan-suppression of PG production via a genetic deletion of cPLA(2) impacts the susceptibility to COX inhibitor-induced GI injury. A panel of COX inhibitors including celecoxib, rofecoxib, sulindac, and aspirin were administered via diet to cPLA(2)(-/-) and cPLA(2)(+/+) littermates. Administration of celecoxib, rofecoxib, and sulindac, but not aspirin, resulted in acute lethality (within 2 weeks) in cPLA(2)(-/-) mice, but not in wild-type littermates. Histomorphological analysis revealed severe GI damage following celecoxib exposure associated with acute bacteremia and sepsis. Intestinal PG levels were reduced equivalently in both genotypes following celecoxib exposure, indicating that PG production was not likely responsible for the differential sensitivity. Gene expression profiling in the small intestines of mice identified drug-related changes among a panel of genes including those involved in mitochondrial function in cPLA(2)(-/-) mice. Further analysis of enterocytic mitochondria showed abnormal morphology as well as impaired ATP production in the intestines from celecoxib-exposed cPLA(2)(-/-) mice. Our data demonstrate that cPLA(2) appears to be an important component in conferring protection against COX inhibitor-induced enteropathy, which may be mediated through affects on enterocytic mitochondria.

Structure-activity relationship of (N)-Methanocarba phosphonate analogues of 5'-AMP as cardioprotective agents acting through a cardiac P2X receptor

P2X receptor activation protects in heart failure models. MRS2339 3, a 2-chloro-AMP derivative containing a (N)-methanocarba (bicyclo[3.1.0]hexane) system, activates this cardioprotective channel. Michaelis-Arbuzov and Wittig reactions provided phosphonate analogues of 3, expected to be stable in vivo due to the C-P bond. After chronic administration via a mini-osmotic pump (Alzet), some analogues significantly increased intact heart contractile function in calsequestrin-overexpressing mice (genetic model of heart failure) compared to vehicle-infused mice (all inactive at the vasodilatory P2Y(1) receptor). Two phosphonates, (1'S,2'R,3'S,4'R,5'S)-4'-(6-amino-2-chloropurin-9-yl)-2',3'-(dihydroxy)-1'-(phosphonomethylene)-bicyclo[3.1.0]hexane, 4 (MRS2775), and its homologue 9 (MRS2935), both 5'-saturated, containing a 2-Cl substitution, improved echocardiography-derived fractional shortening (20.25% and 19.26%, respectively, versus 13.78% in controls), while unsaturated 5'-extended phosphonates, all 2-H analogues, and a CH(3)-phosphonate were inactive. Thus, chronic administration of nucleotidase-resistant phosphonates conferred a beneficial effect, likely via cardiac P2X receptor activation. Thus, we have greatly expanded the range of carbocyclic nucleotide analogues that represent potential candidates for the treatment of heart failure.

Adenosine A(3) receptor stimulation induces protection of skeletal muscle from eccentric exercise-mediated injury

Effective therapy to reduce skeletal muscle injury associated with severe or eccentric exercise is needed. The purpose of this study was to determine whether adenosine receptor stimulation can mediate protection from eccentric exercise-induced muscle injury. Downhill treadmill exercise (-15 degrees ) was used to induce eccentric exercise-mediated skeletal muscle injury. Experiments were conducted in both normal wild-type (WT) mice and also in beta-sarcoglycan knockout dystrophic mice, animals that show an exaggerated muscle damage with the stress of exercise. In the vehicle-treated WT animals, eccentric exercise increased serum creatine kinase (CK) greater than 3-fold to 358.9 +/- 62.7 U/l (SE). This increase was totally abolished by stimulation of the A(3) receptor. In the dystrophic beta-sarcoglycan-null mice, eccentric exercise caused CK levels to reach 55,124 +/- 5,558 U/l. A(3) receptor stimulation in these animals reduced the CK response by nearly 50%. In the dystrophic mice at rest, 10% of the fibers were found to be damaged, as indicated by Evans blue dye staining. While this percentage was doubled after exercise, A(3) receptor stimulation eliminated this increase. Neither the A(1) receptor agonist 2-chloro-N(6)-cyclopentyladenosine (0.05 mg/kg) nor the A(2A) receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine (0.07 mg/kg) protected skeletal muscle from eccentric exercise injury in WT or dystrophic mice. The protective effect of adenosine A(3) receptor stimulation was absent in mice, in which genes for phospholipase C beta2/beta3 (PLCbeta2/beta3) and beta-sarcoglycan were deleted. The present study elucidates a new protective role of the A(3) receptor and PLCbeta2/beta3 and points to a potentially effective therapeutic strategy for eccentric exercise-induced skeletal muscle injury.

Treatment of heart failure by a methanocarba derivative of adenosine monophosphate: implication for a role of cardiac purinergic P2X receptors

Evidence is accumulating to support a potentially important role for purinergic (P2X) receptors in heart failure (HF). We tested the hypothesis that a hydrolysis-resistant nucleotide analog with agonist activity at myocardial P2X receptors (P2XRs) improves the systolic HF phenotype in mouse and dog models. We developed a hydrolysis-resistant adenosine monophosphate derivative, (1'S,2R,3S,4'R,5'S)-4-(6-amino-2-chloro-9H-purin-9-yl)-1-[phosphoryloxymethyl] bicycle[3.1.0]hexane-2,3-diol) (MRS2339), with agonist activity at native cardiac P2XRs. Chronic MRS2339 infusion in postinfarct and calsequestrin (CSQ) mice with HF resulted in higher rates of pressure change (+dP/dt), left ventricle (LV)-developed pressure, and cardiac output in an in vitro working heart model. Heart function in vivo, as determined by echocardiography-derived fractional shortening, was also improved in MRS2339-infused mice. The beneficial effect of MRS2339 was dose-dependent and was identical to that produced by cardiac myocyte-specific overexpression of the P2X(4) receptor. The HF improvement was associated with the preservation of LV wall thickness in both systole and diastole in postinfarct and CSQ mice. In dogs with pacing-induced HF, MRS2339 infusion reduced left ventricular end-diastolic pressure, improved arterial oxygenation, and increased +dP/dt. MRS2339 treatment also decreased LV chamber size in mice and dogs with HF. In murine and canine models of systolic HF, in vivo administration of a P2X nucleotide agonist improved contractile function and cardiac performance. These actions were associated with preserved LV wall thickness and decreased LV remodeling. The data are consistent with a role of cardiac P2XRs in mediating the beneficial effect of this agonist.

Reversal of cardiac myocyte dysfunction as a unique mechanism of rescue by P2X4 receptors in cardiomyopathy

Binary cardiac transgenic (Tg) overexpression of P2X(4) receptors (P2X(4)R) improved the survival of the cardiomyopathic calsequestrin (CSQ) mice. Here we studied the mechanism of rescue using binary P2X(4)R/CSQ Tg and CSQ Tg mice as models. Cellular and intact heart properties were determined by simultaneous sarcomere shortening (SS) and Ca(2+) transients in vitro and echocardiography in vivo. Similar to a delay in death, binary mice exhibited a slowed heart failure progression with a greater left ventricular (LV) fractional shortening (FS) and thickness and a concomitant lesser degree of LV dilatation in both systole and diastole at 8 or 12 wk. By 16 wk, binary hearts showed similarly depressed FS and thinned out LV and equal enlargement of LV as did 12-wk-old CSQ hearts. Binary cardiac myocytes showed higher peak basal cell shortening (CS) and SS as well as greater basal rates of shortening and relaxation than did the CSQ myocytes at either 8 or 12 wk. Similar data were obtained in comparing the Ca(2+) transient. At 16 wk, binary myocytes were like the 12-wk-old CSQ myocytes with equally depressed CS, SS, and Ca(2+) transient. CSQ myocytes were longer than myocytes from wild-type and binary mice at 12 wk of age. At 16 wk, the binary myocyte length increased to that of the 12-wk-old CSQ myocyte, parallel to LV dilatation. The data suggest a unique mechanism, which involves a reversal of cardiac myocyte dysfunction and a delay in heart failure progression. It represents an example of targeting the abnormal failing myocyte in treating heart failure.