Search

Fractures continue to be a global economic burden as there are currently no osteoanabolic drugs approved to accelerate fracture healing. In this study, we aimed to develop an osteoanabolic therapy which activates the Wnt/β-catenin pathway, a molecular driver of endochondral ossification. We hypothesize that using an mRNA-based therapeutic encoding β-catenin could promote cartilage to bone transformation formation by activating the canonical Wnt signaling pathway in chondrocytes. To optimize a delivery platform built on recent advancements in liposomal technologies, two FDA-approved ionizable phospholipids, DLin-MC3-DMA (MC3) and SM-102, were used to fabricate unique ionizable lipid nanoparticle (LNP) formulations and then tested for transfection efficacy both in vitro and in a murine tibia fracture model. Using firefly luciferase mRNA as a reporter gene to track and quantify transfection, SM-102 LNPs showed enhanced transfection efficacy in vitro and prolonged transfection, minimal fracture interference and no localized inflammatory response in vivo over MC3 LNPs. The generated β-cateninGOF mRNA encapsulated in SM-102 LNPs (SM-102-β-cateninGOF mRNA) showed bioactivity in vitro through upregulation of downstream canonical Wnt genes, axin2 and runx2. When testing SM-102-β-cateninGOF mRNA therapeutic in a murine tibia fracture model, histomorphometric analysis showed increased bone and decreased cartilage composition with the 45 μg concentration at 2 weeks post-fracture. μCT testing confirmed that SM-102-β-cateninGOF mRNA promoted bone formation in vivo, revealing significantly more bone volume over total volume in the 45 μg group. Thus, we generated a novel mRNA-based therapeutic encoding a β-catenin mRNA and optimized an SM-102-based LNP to maximize transfection efficacy with a localized delivery.

The interplay among signaling events for endothelial cell (EC) senescence, apoptosis, and activation and how these pathological conditions promote atherosclerosis in the area exposed to disturbed flow (d-flow) in concert remain unclear. The aim of this study was to determine whether telomeric repeat-binding factor 2-interacting protein (TERF2IP), a member of the shelterin complex at the telomere, can regulate EC senescence, apoptosis, and activation simultaneously, and if so, by what molecular mechanisms. We found that d-flow induced p90RSK and TERF2IP interaction in a p90RSK kinase activity-dependent manner. An in vitro kinase assay revealed that p90RSK directly phosphorylated TERF2IP at the serine 205 (S205) residue, and d-flow increased TERF2IP S205 phosphorylation as well as EC senescence, apoptosis, and activation by activating p90RSK. TERF2IP phosphorylation was crucial for nuclear export of the TERF2IP-TRF2 complex, which led to EC activation by cytosolic TERF2IP-mediated NF-κB activation and also to senescence and apoptosis of ECs by depleting TRF2 from the nucleus. Lastly, using EC-specific TERF2IP-knockout (TERF2IP-KO) mice, we found that the depletion of TERF2IP inhibited d-flow-induced EC senescence, apoptosis, and activation, as well as atherosclerotic plaque formation. These findings demonstrate that TERF2IP is an important molecular switch that simultaneously accelerates EC senescence, apoptosis, and activation by S205 phosphorylation.

Hypercholesterolemia, the driving force of atherosclerosis, accelerates the expansion and mobilization of hematopoietic stem and progenitor cells (HSPCs). The molecular determinants connecting hypercholesterolemia with hematopoiesis are unclear. Here, we report that a somite-derived prohematopoietic cue, AIBP, orchestrates HSPC emergence from the hemogenic endothelium, a type of specialized endothelium manifesting hematopoietic potential. Mechanistically, AIBP-mediated cholesterol efflux activates endothelial Srebp2, the master transcription factor for cholesterol biosynthesis, which in turn transactivates Notch and promotes HSPC emergence. Srebp2 inhibition impairs hypercholesterolemia-induced HSPC expansion. Srebp2 activation and Notch up-regulation are associated with HSPC expansion in hypercholesterolemic human subjects. Genome-wide chromatin immunoprecipitation followed by sequencing (ChIP-seq), RNA sequencing (RNA-seq), and assay for transposase-accessible chromatin using sequencing (ATAC-seq) indicate that Srebp2 transregulates Notch pathway genes required for hematopoiesis. Our studies outline an AIBP-regulated Srebp2-dependent paradigm for HSPC emergence in development and HPSC expansion in atherosclerotic cardiovascular disease.

On March 1 and 2, 2018, the National Institutes of Health 2018 Progenitor Cell Translational Consortium, Cardiovascular Bioengineering Symposium, was held at the University of Alabama at Birmingham. Convergence of life sciences and engineering to advance the understanding and treatment of heart failure was the theme of the meeting. Over 150 attendees were present, and >40 scientists presented their latest work on engineering human functional myocardium for disease modeling, drug development, and heart failure research. The scientists, engineers, and physicians in the field of cardiovascular sciences met and discussed the most recent advances in their work and proposed future strategies for overcoming the major roadblocks of cardiovascular bioengineering and therapy. Particular emphasis was given for manipulation and using of stem/progenitor cells, biomaterials, and methods to provide molecular, chemical, and mechanical cues to cells to influence their identity and fate in vitro and in vivo. Collectively, these works are profoundly impacting and progressing toward deciphering the mechanisms and developing novel treatments for left ventricular dysfunction of failing hearts. Here, we present some important perspectives that emerged from this meeting.

Impaired angiogenesis in diabetes is a key process contributing to ischemic diseases such as peripheral arterial disease. Epigenetic mechanisms, including those mediated by long noncoding RNAs (lncRNAs), are crucial links connecting diabetes and the related chronic tissue ischemia. Here we identify the lncRNA that enhances endothelial nitric oxide synthase (eNOS) expression (LEENE) as a regulator of angiogenesis and ischemic response. LEENE expression was decreased in diabetic conditions in cultured endothelial cells (ECs), mouse hind limb muscles, and human arteries. Inhibition of LEENE in human microvascular ECs reduced their angiogenic capacity with a dysregulated angiogenic gene program. Diabetic mice deficient in Leene demonstrated impaired angiogenesis and perfusion following hind limb ischemia. Importantly, overexpression of human LEENE rescued the impaired ischemic response in Leene-knockout mice at tissue functional and single-cell transcriptomic levels. Mechanistically, LEENE RNA promoted transcription of proangiogenic genes in ECs, such as KDR (encoding VEGFR2) and NOS3 (encoding eNOS), potentially by interacting with LEO1, a key component of the RNA polymerase Il-associated factor complex and MYC, a crucial transcription factor for angiogenesis. Taken together, our findings demonstrate an essential role for LEENE in the regulation of angiogenesis and tissue perfusion. Functional enhancement of LEENE to restore angiogenesis for tissue repair and regeneration may represent a potential strategy to tackle ischemic vascular diseases., Introduction Angiogenesis is a unique function of microvascular endothelial cells (MVECs) that involves highly orchestrated interactions among growth factors, membrane receptors, and signaling molecules (1, 2). While physiological stimuli, e.g., [...]

Myocardial recovery is characterized by a return toward normal structure and function of the heart after an injury. Mechanisms of myocardial recovery include restoration and/or adaptation of myocyte structure and function, mitochondrial activity and number, metabolic homeostasis, electrophysiological stability, extracellular matrix remodeling, and myocardial perfusion. Myocardial regeneration is an element of myocardial recovery that involves the generation of new myocardial tissue, a process which is limited in adult humans but may be therapeutically augmented. Understanding the mechanisms of myocardial recovery and myocardial regeneration will lead to novel therapies for heart failure. [ABSTRACT FROM AUTHOR]

BackgroundThe beneficial outcome associated with the use of proton pump inhibitors (PPIs) in idiopathic pulmonary fibrosis (IPF) has been reported in retrospective studies. To date, no prospective study has been conducted to confirm these outcomes. In addition, the potential mechanism by which PPIs improve measures of lung function and/or transplant-free survival in IPF has not been elucidated.MethodsHere, we used biochemical, cell biological and preclinical studies to evaluate regulation of markers associated with inflammation and fibrosis. In our in vitro studies, we exposed primary lung fibroblasts, epithelial and endothelial cells to ionizing radiation or bleomycin; stimuli typically used to induce inflammation and fibrosis. In addition, we cultured lung fibroblasts from IPF patients and studied the effect of esomeprazole on collagen release. Our preclinical study tested efficacy of esomeprazole in a rat model of bleomycin-induced lung injury. Furthermore, we performed retrospective analysis of interstitial lung disease (ILD) databases to examine the effect of PPIs on transplant-free survival.ResultsThe cell culture studies revealed that esomeprazole controls inflammation by suppressing the expression of pro-inflammatory molecules including vascular cell adhesion molecule-1, inducible nitric oxide synthase, tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6). The antioxidant effect is associated with strong induction of the stress-inducible cytoprotective protein heme oxygenase-1 (HO1) and the antifibrotic effect is associated with potent inhibition of fibroblast proliferation as well as downregulation of profibrotic proteins including receptors for transforming growth factor β (TGFβ), fibronectin and matrix metalloproteinases (MMPs). Furthermore, esomeprazole showed robust effect in mitigating the inflammatory and fibrotic responses in a murine model of acute lung injury. Finally, retrospective analysis of two ILD databases was performed to assess the effect of PPIs on transplant-free survival in IPF patients. Intriguingly, this data demonstrated that IPF patients on PPIs had prolonged survival over controls (median survival of 3.4 vs 2 years).ConclusionsOverall, these data indicate the possibility that PPIs may have protective function in IPF by directly modulating the disease process and suggest that they may have other clinical utility in the treatment of extra-intestinal diseases characterized by inflammatory and/or fibrotic phases.

Background and aimsProton pump inhibitors (PPIs) have been associated with adverse clinical outcomes amongst clopidogrel users after an acute coronary syndrome. Recent pre-clinical results suggest that this risk might extend to subjects without any prior history of cardiovascular disease. We explore this potential risk in the general population via data-mining approaches.MethodsUsing a novel approach for mining clinical data for pharmacovigilance, we queried over 16 million clinical documents on 2.9 million individuals to examine whether PPI usage was associated with cardiovascular risk in the general population.ResultsIn multiple data sources, we found gastroesophageal reflux disease (GERD) patients exposed to PPIs to have a 1.16 fold increased association (95% CI 1.09-1.24) with myocardial infarction (MI). Survival analysis in a prospective cohort found a two-fold (HR = 2.00; 95% CI 1.07-3.78; P = 0.031) increase in association with cardiovascular mortality. We found that this association exists regardless of clopidogrel use. We also found that H2 blockers, an alternate treatment for GERD, were not associated with increased cardiovascular risk; had they been in place, such pharmacovigilance algorithms could have flagged this risk as early as the year 2000.ConclusionsConsistent with our pre-clinical findings that PPIs may adversely impact vascular function, our data-mining study supports the association of PPI exposure with risk for MI in the general population. These data provide an example of how a combination of experimental studies and data-mining approaches can be applied to prioritize drug safety signals for further investigation.

ObjectiveTransdifferentiation of fibroblasts to endothelial cells (ECs) may provide a novel therapeutic avenue for diseases, including ischemia and fibrosis. Here, we demonstrate that human fibroblasts can be transdifferentiated into functional ECs by using only 2 factors, Oct4 and Klf4, under inductive signaling conditions.Approach and resultsTo determine whether human fibroblasts could be converted into ECs by transient expression of pluripotency factors, human neonatal fibroblasts were transduced with lentiviruses encoding Oct4 and Klf4 in the presence of soluble factors that promote the induction of an endothelial program. After 28 days, clusters of induced endothelial (iEnd) cells seemed and were isolated for further propagation and subsequent characterization. The iEnd cells resembled primary human ECs in their transcriptional signature by expressing endothelial phenotypic markers, such as CD31, vascular endothelial-cadherin, and von Willebrand Factor. Furthermore, the iEnd cells could incorporate acetylated low-density lipoprotein and form vascular structures in vitro and in vivo. When injected into the ischemic limb of mice, the iEnd cells engrafted, increased capillary density, and enhanced tissue perfusion. During the transdifferentiation process, the endogenous pluripotency network was not activated, suggesting that this process bypassed a pluripotent intermediate step.ConclusionsPluripotent factor-induced transdifferentiation can be successfully applied for generating functional autologous ECs for therapeutic applications.

The current state of the art in post-marketing drug surveillance utilizes voluntarily submitted reports of suspected adverse drug reactions. We present data mining methods that transform unstructured patient notes taken by doctors, nurses and other clinicians into a de-identified, temporally ordered, patient-feature matrix using standardized medical terminologies. We demonstrate how to use the resulting high-throughput data to monitor for adverse drug events based on the clinical notes in the EHR.

Recent evidence suggests human embryonic stem cell (hESC) and induced pluripotent stem (iPS) cell lines have differences in their epigenetic marks and transcriptomes, yet the impact of these differences on subsequent terminally differentiated cells is less well understood. Comparison of purified, homogeneous populations of somatic cells derived from multiple independent human iPS and ES lines will be required to address this critical question. Here, we report a differentiation protocol based on embryonic development that consistently yields large numbers of endothelial cells (ECs) derived from multiple hESCs or iPS cells. Mesoderm differentiation of embryoid bodies was maximized, and defined growth factors were used to generate KDR(+) EC progenitors. Magnetic purification of a KDR(+) progenitor subpopulation resulted in an expanding, homogeneous pool of ECs that expressed EC markers and had functional properties of ECs. Comparison of the transcriptomes revealed limited gene expression variability between multiple lines of human iPS-derived ECs or between lines of ES- and iPS-derived ECs. These results demonstrate a method to generate large numbers of pure human EC progenitors and differentiated ECs from pluripotent stem cells and suggest individual lineages derived from human iPS cells may have significantly less variance than their pluripotent founders.