Genetic deletion of c-Jun amino-terminal kinase 3 (JNK3) modestly increases disease severity in a mouse model of multiple sclerosis.

The c-Jun amino terminal kinases (JNKs) regulate transcription, and studies suggest they contribute to neuropathology in the EAE model of MS. To examine the role of the JNK3 isoform, we compared EAE in JNK3 null mice to wild type (WT) littermates. Although disease severity was similar in female mice, in male JNK3 null mice the day of onset and time to reach 100% incidence occurred sooner, and disease severity was increased.

Case Report and Literature Review: Post-Arthroscopy Pneumothorax with Anterior Decompression.

Introduction: Emergency providers should recognize that pneumothorax is a rare but serious complication of shoulder arthroscopy that may require a unique approach to decompression.

Case Report: We present a case of a 60-year-old female who presented to the emergency department with right-sided facial swelling, voice change, and shortness of breath three hours after an elective arthroscopic right rotator-cuff repair and was noted to have a right-sided pneumothorax. We also describe a potential novel approach to chest tube decompression that maintains shoulder adduction in patients with recently repaired rotator cuffs.

ANG1 treatment reduces muscle pathology and prevents a decline in perfusion in DMD mice.

Vascular endothelial growth factor (VEGF) and other pro-angiogenic growth factors have been investigated to enhance muscle tissue perfusion and repair in Duchenne muscular dystrophy (DMD). Current understanding is limited by a lack of functional data following in vivo delivery of these growth factors. We previously used dynamic contrast-enhanced computed tomography to monitor disease progression in murine models of DMD, but no study to date has utilized this imaging technique to assess vascular therapy in a preclinical model of DMD.

VEGF induces stress fiber formation in fibroblasts isolated from dystrophic muscle.

Treatment with vascular endothelial growth factor (VEGF) to reduce ischemia and enhance both endogenous muscle repair and regenerative cell therapy in Duchenne muscular dystrophy (DMD) has been widely proposed in recent years. However, the interaction between angiogenesis and fibrosis, a hallmark feature of DMD, remains unclear. To date, it has not been determined whether VEGF exerts a pro-fibrotic effect on DMD-derived fibroblasts, which may contribute to further disease progression.

Skeletal muscle fibrosis in the mdx/utrn+/- mouse validates its suitability as a murine model of Duchenne muscular dystrophy.

Various therapeutic approaches have been studied for the treatment of Duchenne muscular dystrophy (DMD), but none of these approaches have led to significant long-term effects in patients. One reason for this observed inefficacy may be the use of inappropriate animal models for the testing of therapeutic agents. The mdx mouse is the most widely used murine model of DMD, yet it does not model the fibrotic progression observed in patients.

Application of 3-d echocardiography and gated micro-computed tomography to assess cardiomyopathy in a mouse model of duchenne muscular dystrophy.

The purpose of this study was to measure changes in cardiac function as cardiomyopathy progresses in a mouse model of Duchenne muscular dystrophy using 3-D ECG-gated echocardiography. This study is the first to correlate cardiac volumes acquired using 3-D echocardiography with those acquired using retrospectively gated micro-computed tomography (CT). Both were further compared with standard M-mode echocardiography and histologic analyses.

Analysis of chondrogenesis using micromass cultures of limb mesenchyme.

High-density micromass cultures of embryonic mesenchymal cells have proved to be an invaluable model for studying the entire chondrogenic program, from precartilaginous condensations through to chondrocyte hypertrophy. This culture model also provides a powerful system in which to explore the function of various factors in the commitment and differentiation of mesenchymal cells to the chondrogenic lineage. In this regard, micromass cultures provide a consistent and robust model for investigating the effects of genetic manipulations on skeletal phenotypes and for delineating their molecular basis.

Characterization of a far-red analog of ghrelin for imaging GHS-R in P19-derived cardiomyocytes.

Ghrelin and its receptor, the growth hormone secretagogue receptor (GHS-R), are expressed in the heart, and may function to promote cardiomyocyte survival, differentiation and contractility. Previously, we had generated a truncated analog of ghrelin conjugated to fluorescein isothiocyanate for the purposes of determining GHS-R expression in situ. We now report the generation and characterization of a far-red ghrelin analog, [Dpr(3)(octanoyl), Lys(19)(Cy5)]ghrelin (1-19), and show that it can be used to image changes in GHS-R in developing cardiomyocytes.

Use of imaging biomarkers to assess perfusion and glucose metabolism in the skeletal muscle of dystrophic mice.

Background: Duchenne muscular dystrophy (DMD) is a severe neuromuscular disease that affects 1 in 3500 boys. The disease is characterized by progressive muscle degeneration that results from mutations in or loss of the cytoskeletal protein, dystrophin, from the glycoprotein membrane complex, thus increasing the susceptibility of contractile muscle to injury. To date, disease progression is typically assessed using invasive techniques such as muscle biopsies, and while there are recent reports of the use of magnetic resonance, ultrasound and optical imaging technologies to address the issue of disease progression and monitoring therapeutic intervention in dystrophic mice, our study aims to validate the use of imaging biomarkers (muscle perfusion and metabolism) in a longitudinal assessment of skeletal muscle degeneration/regeneration in two murine models of muscular dystrophy.

Fas ligand expression on T cells is sufficient to prevent prolonged airway inflammation in a murine model of asthma.

Our previous studies revealed that, in a murine model of asthma, mice that received Fas-deficient T cells developed a prolonged phase of airway inflammation, mucus production, and airway hyperreactivity that failed to resolve even 6 weeks after the last challenge. To investigate how Fas-Fas ligand (FasL) interaction occurs between T cells and other cells in vivo, Gld mice with abnormalities of the FasL signaling pathway were used. The reconstituted mice were made by transferring T cells from B6 or Gld mice to Rag(-/-) or FasL-deficient Rag(-/-) mice.

Human embryonic stem cell stability.

Human embryonic stem cells (hESCs) are derived from human preimplantation embryos, and exhibit the defining characteristics of immortality and pluripotency. Indeed, these cell populations can be maintained for several years in continuous culture, and undergo hundreds of population doublings. hESCs are thus likely candidates for source of cells for cell replacement therapies.

BMP action in skeletogenesis involves attenuation of retinoid signaling.

The bone morphogenetic protein (BMP) and growth and differentiation factor (GDF) signaling pathways have well-established and essential roles within the developing skeleton in coordinating the formation of cartilaginous anlagen. However, the identification of bona fide targets that underlie the action of these signaling molecules in chondrogenesis has remained elusive. We have identified the gene for the retinoic acid (RA) synthesis enzyme Aldh1a2 as a principal target of BMP signaling; prochondrogenic BMPs or GDFs lead to attenuation of Aldh1a2 expression and, consequently, to reduced activation of the retinoid signaling pathway.

X-inactivation status varies in human embryonic stem cell lines.

Human embryonic stem cells (hESCs) derived from human blastocysts have an apparently unlimited proliferative capacity and can differentiate into ectoderm, mesoderm, and endoderm. As such, hESC lines have enormous potential for use in cell replacement therapies. It must first be demonstrated, however, that hESCs maintain a stable karyotype and phenotype and that gene expression is appropriately regulated.

Characterization and culture of human embryonic stem cells.

Human embryonic stem cells have been defined as self-renewing cells that can give rise to many types of cells of the body. How and whether these cells can be manipulated to replace cells in diseased tissues, used to screen drugs and toxins, or studied to better understand normal development, however, depends on knowing more about their fundamental properties. Many different human embryonic stem cell lines--which are pluripotent, proliferate indefinitely in vitro and maintain a normal, euploid karyotype over extended culture--have now been derived, but whether these cell lines are in fact equivalent remains unclear.

Revisiting the role of retinoid signaling in skeletal development.

Several years ago, it was discovered that an imbalance of vitamin A during embryonic development has dramatic teratogenic effects. These effects have since been attributed to vitamin A's most active metabolite, retinoic acid (RA), which itself profoundly influences the development of multiple organs including the skeleton. After decades of study, researchers are still uncovering the molecular basis whereby retinoids regulate skeletal development.

Molecular mechanisms regulating chondroblast differentiation.

Background: Formation of the cartilage template involves a multi-step process in which prechondrogenic mesenchymal cells form condensations prior to differentiating into matrix-producing chondroblasts. Retinoids, particularly retinoic acid, are among the numerous signaling molecules that have been implicated in this process. A proper balance of retinoids is essential for normal skeletal development in that too much or too little negatively impacts skeletogenesis.

Chemokine Regulation of Immune-mediated Demyelinating Disease.

Experimental autoimmune encephalomyelitis (EAE) is a CD4+ Th1-mediated demyelinating disease of the central nervous system (CNS), which serves as a model for multiple schlerosis (MS). A hallmark in the pathogenesis of this disease is the emigration of T cells and monocytes from the blood to the CNS. Chemokines are small-molecular-weight chemotactic peptides, which are ligands for seven transmembrane-spanning, G protein-coupled receptors and which deliver signals leading to a variety of T cell functions including costimulation, cytokine expression, differentiation, and integrin activation.