CD45 regulates retention, motility, and numbers of hematopoietic progenitors, and affects osteoclast remodeling of metaphyseal trabecules

The CD45 phosphatase is uniquely expressed by all leukocytes, but its role in regulating hematopoietic progenitors is poorly understood. We show that enhanced CD45 expression on bone marrow (BM) leukocytes correlates with increased cell motility in response to stress signals. Moreover, immature CD45 knockout (KO) cells showed defective motility, including reduced homing (both steady state and in response to stromal-derived factor 1) and reduced granulocyte colony-stimulating factor mobilization. These defects were associated with increased cell adhesion mediated by reduced matrix metalloproteinase 9 secretion and imbalanced Src kinase activity. Poor mobilization of CD45KO progenitors by the receptor activator of nuclear factor κB ligand, and impaired modulation of the endosteal components osteopontin and stem cell factor, suggested defective osteoclast function. Indeed, CD45KO osteoclasts exhibited impaired bone remodeling and abnormal morphology, which we attributed to defective cell fusion and Src function. This led to irregular distribution of metaphyseal bone trabecules, a region enriched with stem cell niches. Consequently, CD45KO mice had less primitive cells in the BM and increased numbers of these cells in the spleen, yet with reduced homing and repopulation potential. Uncoupling environmental and intrinsic defects in chimeric mice, we demonstrated that CD45 regulates progenitor movement and retention by influencing both the hematopoietic and nonhematopoietic compartments

In the Hunt for Therapeutic Targets: Mimicking the Growth, Metastasis, and Stromal Associations of Early-Stage Lung Cancer Using a Novel Orthotopic Animal Model

BackgroundThe existing shortage of animal models that properly mimic the progression of early-stage human lung cancer from a solitary confined tumor to an invasive metastatic disease hinders accurate characterization of key interactions between lung cancer cells and their stroma. We herein describe a novel orthotopic animal model that addresses these concerns and consequently serves as an attractive platform to study tumor–stromal cell interactions under conditions that reflect early-stage lung cancer.MethodsUnlike previous methodologies, we directly injected small numbers of human or murine lung cancer cells into murine's left lung and longitudinally monitored disease progression. Next, we used green fluorescent protein-tagged tumor cells and immuno-fluorescent staining to determine the tumor's microanatomic distribution and to look for tumor-infiltrating immune cells and stromal cells. Finally, we compared chemokine gene expression patterns in the tumor and lung microenvironment.ResultsWe successfully generated a solitary pulmonary nodule surrounded by normal lung parenchyma that grew locally and spread distally over time. Notably, we found that both fibroblasts and leukocytes are recruited to the tumor's margins and that distinct myeloid cell attracting and CCR2-binding chemokines are specifically induced in the tumor microenvironment.ConclusionOur orthotopic lung cancer model closely mimics the pathologic sequence of events that characterizes early-stage human lung cancer propagation. It further introduces new means to monitor tumor–stromal cell interactions and offers unique opportunities to test therapeutic targets under conditions that reflect early-stage lung cancer. We argue that for such purposes our model is superior to lung cancer models that are based either on genetic induction of epithelial transformation or on ectopic transplantation of malignant cells

Моделирование струйного размыва донных отложений в нефтяных резервуарах

Объект исследования: электромеханическое устройство для размыва донных отложений в резервуарах вертикальных стальных. Предмет исследования – размыв донных отложений в резервуарах хранения нефти. Цель работы – Анализ существующих методов борьбы с донными отложениями. Моделирование гидродинамических процессов размыва донных отложений в резервуарах вертикальных стальных.Object of research: an electromechanical device for washing bottom sediments in vertical steel tanks. The subject of research is the erosion of bottom sediments in oil storage tanks. Purpose of the work - Analysis of existing methods for dealing with bottom sediments. Simulation of hydrodynamic processes of erosion of bottom sediments in vertical steel tanks

Characterization of the expression of cytokeratins 5, 8, and 14 in mouse thymic epithelial cells during thymus regeneration following acute thymic involution

The thymus is a central lymphoid organ for T cell development. Thymic epithelial cells (TECs) constitute a major component of the thymic stroma, which provides a specialized microenvironment for survival, proliferation, and differentiation of immature T cells. In this study, subsets of TECs were examined immunohistochemically to investigate their cytokeratin (CK) expression patterns during thymus regeneration following thymic involution induced by cyclophosphamide treatment. The results demonstrated that both normal and regenerating mouse thymuses showed a similar CK expression pattern. The major medullary TECs (mTEC) subset, which is stellate in appearance, exhibited CK5 and CK14 staining, and the minor mTEC subset, which is globular in appearance, exhibited CK8 staining, whereas the vast majority of cortical TECs (cTECs) expressed CK8 during thymus regeneration. Remarkably, the levels of CK5 and CK14 expression were enhanced in mTECs, and CK8 expression was upregulated in cTECs during mouse thymus regeneration after cyclophosphamide-induced acute thymic involution. Of special interest, a relatively high number of CK5+CK8+ TEC progenitors occurred in the thymic cortex during thymus regeneration. Taken together, these findings shed more light on the role of CK5, CK8, and CK14 in the physiology of TECs during mouse thymus regeneration, and on the characterization of TEC progenitors for restoration of the epithelial network and for concomitant regeneration of the adult thymus

Embryonic Pig Pancreatic Tissue Transplantation for the Treatment of Diabetes

BACKGROUND: Transplantation of embryonic pig pancreatic tissue as a source of insulin has been suggested for the cure of diabetes. However, previous limited clinical trials failed in their attempts to treat diabetic patients by transplantation of advanced gestational age porcine embryonic pancreas. In the present study we examined growth potential, functionality, and immunogenicity of pig embryonic pancreatic tissue harvested at different gestational ages. METHODS AND FINDINGS: Implantation of embryonic pig pancreatic tissues of different gestational ages in SCID mice reveals that embryonic day 42 (E42) pig pancreas can enable a massive growth of pig islets for prolonged periods and restore normoglycemia in diabetic mice. Furthermore, both direct and indirect T cell rejection responses to the xenogeneic tissue demonstrated that E42 tissue, in comparison to E56 or later embryonic tissues, exhibits markedly reduced immunogenicity. Finally, fully immunocompetent diabetic mice grafted with the E42 pig pancreatic tissue and treated with an immunosuppression protocol comprising CTLA4-Ig and anti–CD40 ligand (anti-CD40L) attained normal blood glucose levels, eliminating the need for insulin. CONCLUSIONS: These results emphasize the importance of selecting embryonic tissue of the correct gestational age for optimal growth and function and for reduced immunogenicity, and provide a proof of principle for the therapeutic potential of E42 embryonic pig pancreatic tissue transplantation in diabetes

Alpha smooth muscle actin (α-SM actin) in normal human ovaries, in ovarian stromal hyperplasia and in ovarian neoplasms

An immunohistochemical investigation of alpha-smooth muscle actin (α-SM actin) using the monoclonal anti-α-SM-1 antibody was carried out in 15 normal ovaries, in three ovaries with stromal hyperplasia and in 27 neoplastic ovaries. In selected cases the pattern of actin isoforms was examined by means of 2 D-gel electrophoresis. In addition, the tissues were stained for vimentin and desmin. In normal ovaries α-SM actin was found in the inner cortex and in the theca externa. In ovarian stromal hyperplasia expression of α-SM actin was minimal or absent. In primary and metastatic epithelial tumors there was positive stromal staining for α-SM actin, especially in the vicinity of epithelial elements. This tended to be more widespread in malignant neoplasms. Thecomas did not express α-SM-actin and could thus be differentiated from leiomyomas which stained intensely for α-SM actin. Only focal stromal staining of α-SM actin was observed in granulosa and germ cell tumors. In all the tissues studied blood vessels were strongly positive for α-SM actin. Desmin, although present in the stroma of most of the specimens, was less abundant than α-SM actin. We concluded that α-SM actin is a component of the normal human ovary where it may contribute to the contractility of its stroma. Its absence in the normal outer cortex and theca interna, and in stromal hyperplasia and thecoma implies that sex hormones do not constitute a stimulus for α-SM actin production in the ovary. Among neoplasms it is most widely represented in the stroma of epithelial tumors in which it may reflect stromal stimulation mediated by neoplastic epithelium. © 1989 Springer-Verlag