Skeletal muscle LIM protein 1 regulates integrin-mediated myoblast adhesion,spreading, and migration

The skeletal muscle LIM protein 1 (SLIM1) is highly expressed in skeletal and cardiac muscle, and itsexpression is downregulated significantly in dilated humancardiomyopathy. However, the function of SLIM1 is unknown. In thisstudy, we investigated the intracellular localization of SLIM1.Endogenous and recombinant SLIM1 localized to the nucleus, stressfibers, and focal adhesions in skeletal myoblasts plated onfibronectin, collagen, or laminin. However, after inhibition ofintegrin signaling either by plating on poly-L-lysine or bysoluble RGD peptide, SLIM1 localized diffusely in the cytosol, withdecreased nuclear expression. Disruption of the actin cytoskeleton bycytochalasin D did not inhibit nuclear localization of SLIM1 inintegrin-activated cells. Green fluorescent protein-tagged SLIM1shuttled in the nucleus of untransfected NIH 3T3 cells, in aheterokaryon fusion assay. Overexpression of SLIM1 in Sol8 myoblastsinhibited cell adhesion and promoted cell spreading and migration.These studies show SLIM1 localizes in an integrin-dependent manner tothe nucleus and focal adhesions where it functions downstream ofintegrin activation to promote cell spreading and migration.

     

A tetravalent dengue nanoparticle stimulates antibody production in mice

Background

Dengue is a major public health problem worldwide, especially in the tropical and subtropical regions of the world. Infection with a single Dengue virus (DENV) serotype causes a mild, self-limiting febrile illness called dengue fever. However, a subset of patients experiencing secondary infection with a different serotype progresses to the severe form of the disease, dengue hemorrhagic fever/dengue shock syndrome. Currently, there are no licensed vaccines or antiviral drugs to prevent or treat dengue infections. Biodegradable nanoparticles coated with proteins represent a promising method for in vivo delivery of vaccines.

Findings

Here, we used a murine model to evaluate the IgG production after administration of inactivated DENV corresponding to all four serotypes adsorbed to bovine serum albumin nanoparticles. This formulation induced a production of anti-DENV IgG antibodies (p < 0.001). However, plaque reduction neutralization assays with the four DENV serotypes revealed that these antibodies have no neutralizing activity in the dilutions tested.

Conclusions

Our results show that while the nanoparticle system induces humoral responses against DENV, further investigation with different DENV antigens will be required to improve immunogenicity, epitope specicity, and functional activity to make this platform a viable option for DENV vaccines.     

The influence of therapeutic radiation on the patterns of bone marrow in ovary-intact and ovariectomized mice

Background

The functional components of bone marrow (i.e., the hematopoietic and stromal populations) and the adjacent bone have traditionally been evaluated incompletely as distinct entities rather than the integrated system. We perturbed this system in vivo using a medically relevant radiation model in the presence or absence of ovarian function to understand integrated tissue interaction.

Methodology/Principal Findings

Ovary-intact and ovariectomized mice underwent either no radiation or single fractional 16 Gy radiation to the caudal skeleton (I±R, OVX±R). Marrow fat, hematopoietic cellularity, and cancellous bone volume fraction (BV/TV %) were assessed. Ovariectomy alone did not significantly reduce marrow cellularity in non-irradiated mice (OVX−R vs. I−R, p = 0.8445) after 30 days; however it impaired the hematopoietic recovery of marrow following radiation exposure (OVX+R vs. I+R, p = 0.0092). The combination of radiation and OVX dramatically increases marrow fat compared to either factor alone (p = 0.0062). The synergistic effect was also apparent in the reduction of hematopoietic marrow cellularity (p = 0.0661); however it was absent in BV/TV% changes (p = 0.2520). The expected inverse relationship between marrow adiposity vs. hematopoietic cellularity and bone volume was observed. Interestingly compared with OVX mice, intact mice demonstrated double the reduction in hematopoietic cellularity and a tenfold greater degree of bone loss for a given unit of expansion in marrow fat.

Conclusions/Significance

Ovariectomy prior to delivery of a clinically-relevant focal radiation exposure in mice, exacerbated post-radiation adipose accumulation in the marrow space but blunted bone loss and hematopoietic suppression. In the normally coupled homeostatic relationship between the bone and marrow domains, OVX appears to alter feedback mechanisms. Confirmation of this non-linear phenomenon (presumably due to differential radiosensitivity) and demonstration of the mechanism of action is needed to provide strategies to diminish the effect of radiation on exposed tissues.     

Characteristics of temporal patterns of cortisol and luteinizing hormone in primiparous,postpartum, anovular,suckled, beef cows exposed acutely to bulls

Background  

The physiological mechanism by which bulls stimulate resumption of ovarian cycling activity in postpartum, anovular, suckled cows after calving may involve the concurrent activation of the hypothalamic-hypophyseal-ovarian (HPO) axis and hypothalamic-hypophyseal-adrenal (HPA) axis. Thus, the objectives of this experiment were to determine if characteristics of temporal patterns of cortisol and luteinizing hormone (LH) in postpartum, anovular, beef cows are influenced by acute exposure to bulls. The null hypotheses were that daily, temporal characteristics of cortisol and LH concentration patterns do not differ between cows exposed acutely to bulls or steers.     

Human oesophageal submucosal glands. Their detection mucin, enzyme and secretory protein content

Human oesophageal submucosal glands may be regularly demonstrated by first exposing the oesophageal lumen to toluidine blue which reveals the duct ostia. Four types of cell were identified in the glands - mucous, subsidiary or serous, myoepithelial and oncocytes. The mucous cell contained neutral, sialated and sulphated mucins. The subsidiary cells held smaller amounts of neutral and sialated mucin, plus fucosyl residues. No lipids were detectable histochemically. ATP-ase and alkaline phosphatase were shown in the capillary endothelium. The duct epithelium showed some nonspecific esterase activity not sensitive to E 600. By immunoperoxidase techniques, the duct epithelium was shown to be rich in cytokeratin. The subsidiary cells contained lysozyme, CEA and pepsinogen. B lymphocytes composed most of the periductular lymphoid aggregates, although some T cells were found there and also intraepithelial and subepithelial in relation to the stratified squamous epithelium lining the oesophagus. Langerhans' cells were also demonstrated as intraepithelial by several techniques.     

Human oesophageal submucosal glands

Summary Human oesophageal submucosal glands may be regularly demonstrated by first exposing the oesophageal lumen to toluidine blue which reveals the duct ostia. Four types of cell were identified in the glands-mucous, subsidiary or serous, myoepithelial and oncocytes. The mucous cell contained neutral, sialated and sulphated mucins. The subsidiary cells held smaller amounts of neutral and sialated mucin, plus fucosyl residues. No lipids were detectable histochemically. ATP-ase and alkaline phosphatase were shown in the capillary endothelium. The duct epithelium showed some nonspecific esterase activity not sensitive to E-600. By immunoperoxidase techniques, the duct epithelium was shown to be rich in cytokeratin. The subsidiary cells contained lysozyme, CEA and pepsinogen. B lymphocytes composed most of the periductular lymphoid aggregates, although some T cells were found there and also intraepithelially and subepithelially in relation to the stratitied squamous epithelium lining the oesophagus. Langerhans' cells were also demonstrated intraepithelially by several techniques.