Temporal dynamics of the developing lung transcriptome in three common inbred strains of laboratory mice reveals multiple stages of postnatal alveolar development

To characterize temporal patterns of transcriptional activity during normal lung development, we generated genome wide gene expression data for 26 pre- and post-natal time points in three common inbred strains of laboratory mice (C57BL/6J, A/J, and C3H/HeJ). Using Principal Component Analysis and least squares regression modeling, we identified both strain-independent and strain-dependent patterns of gene expression. The 4,683 genes contributing to the strain-independent expression patterns were used to define a murine Developing Lung Characteristic Subtranscriptome (mDLCS). Regression modeling of the Principal Components supported the four canonical stages of mammalian embryonic lung development (embryonic, pseudoglandular, canalicular, saccular) defined previously by morphology and histology. For postnatal alveolar development, the regression model was consistent with four stages of alveolarization characterized by episodic transcriptional activity of genes related to pulmonary vascularization. Genes expressed in a strain-dependent manner were enriched for annotations related to neurogenesis, extracellular matrix organization, and Wnt signaling. Finally, a comparison of mouse and human transcriptomics from pre-natal stages of lung development revealed conservation of pathways associated with cell cycle, axon guidance, immune function, and metabolism as well as organism-specific expression of genes associated with extracellular matrix organization and protein modification. The mouse lung development transcriptome data generated for this study serves as a unique reference set to identify genes and pathways essential for normal mammalian lung development and for investigations into the developmental origins of respiratory disease and cancer. The gene expression data are available from the Gene Expression Omnibus (GEO) archive (GSE74243). Temporal expression patterns of mouse genes can be investigated using a study specific web resource (http://lungdevelopment.jax.org)

Моделирование формирования структуры металломатричных композитов в процессе синтеза с оценкой эффективных свойств

Работа посвящена моделированию процесса кристаллизации композита с металлической матрицей и твердыми включениями с учетом условий синтеза (давление, скорость охлаждения), моделированию процесса формирования переходной зоны между частицами и матрицей и расчету эффективных свойств получаемых композитов.The work is devoted to modeling the crystallization process of metal matrix composite with solid inclusions, taking into account the synthesis conditions (pressure, cooling rate), to modeling the formation of the transition zone between particles and matrix, and calculating the effective properties of the resulting composites

A Leishmania ortholog of macrophage migration inhibitory factor modulates host macrophage responses

Parasitic organisms have evolved specialized strategies to evade host immune defense mechanisms. This thesis describes the characterization of two Leishmania major-encoded orthologs of the pro-inflammatory pleiotropic cytokine, macrophage migration inhibitory factor (MIF). These two MIF-like sequences show 22% sequence identity when aligned with human MIF, and are most likely the result of gene duplication. The Lm1740MIF and Lm1750MIF genes (58% identity) are expressed in all developmental stages of L. major. Interestingly, LmMIF expression levels were shown to be significantly up-regulated in the procyclic life-stage of the parasite, which exists solely in the host sand fly. Furthermore, Lm1750MIF levels were 3–4 fold higher than Lm1740MIF levels. The finding that LmMIF is expressed in procyclic parasites might reveal a new function for MIF within its vector, the sandfly. Furthermore, the work described here postulated that Lm1740MIF might interact with the macrophage surface receptor, CD74. To evaluate this hypothesis, binding analyses using surface plasmon resonance (Biacore) were carried out. The Kd of MIF was previously approximated to be between 9 × 10-9 to 2.3 × 10-10. Lm1740MIF showed a significant binding interaction with CD74 (Kd=2.9 × 10-8 M). Thus, there is sufficient structural homology between Lm1740MIF and human MIF to permit high-affinity binding to CD74. To investigate whether Lm1740MIF induces ERK1/2 activation in a CD74-dependent manner and to determine if it inhibits activation-induced macrophage apoptosis similar to its mammalian counterpart, the ability of Lm1740MIF to stimulate ERK1/2 phosphorylation as well as to inhibit Ser15 phosphorylation of the tumor suppressor p53 was tested. Macrophages treated with Lm1740MIF were assessed for apoptosis by the ELISA method; additionally, Western blot analyses for ERK1/2 and p53 activation were performed. The interaction between Lm1740MIF and CD74 led to an similar signal transduction response in macrophages obtained from both wild-type and C3H/HeJ mice, indicating that signaling was not due to the presence of contaminating endotoxin. Lm1740MIF was functionally active in both ERK1/2 signaling and protection from apoptosis, although the level of activity was generally lower than for mammalian MIF, an observation that appeared consistent with the lower Kd of Lm1740MIF for the CD74 receptor. For mouse MIF, protection from apoptosis was dependent on CD74, and the response was associated with a decrease in the cytoplasmic content of Ser15-phosphorylated p53. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within macrophages and contribute to its evasion from immune destruction. The precise cellular pathway by which Lm1740MIF activates CD74 and whether Lm1740MIF modulates additional pathways that are important for either intracellular parasitism or for immune evasion remains to be determined. In conclusion, the presented results indicate that a Leishmania ortholog of the cytokine MIF has the ability to activate the human MIF receptor and influence the functional responses of monocytes/macrophages. Because Leishmania is an intracellular infection of monocytes/macrophages, Leishmania-encoded MIF is hypothesized to sustain monocyte/macrophage survival and contribute to the persistence of the parasite for completion of its infectious life cycle. While these data are consistent with a role for Leishmania MIF in modulating host-immune responses, they do not exclude the possibility that Lm1740MIF may function in the growth and/or replication of the parasite

A Leishmania ortholog of macrophage migration inhibitory factor modulates host macrophage responses

Parasitic organisms have evolved specialized strategies to evade host immune defense mechanisms. This thesis describes the characterization of two Leishmania major-encoded orthologs of the pro-inflammatory pleiotropic cytokine, macrophage migration inhibitory factor (MIF). These two MIF-like sequences show 22% sequence identity when aligned with human MIF, and are most likely the result of gene duplication. The Lm1740MIF and Lm1750MIF genes (58% identity) are expressed in all developmental stages of L. major. Interestingly, LmMIF expression levels were shown to be significantly up-regulated in the procyclic life-stage of the parasite, which exists solely in the host sand fly. Furthermore, Lm1750MIF levels were 3–4 fold higher than Lm1740MIF levels. The finding that LmMIF is expressed in procyclic parasites might reveal a new function for MIF within its vector, the sandfly. Furthermore, the work described here postulated that Lm1740MIF might interact with the macrophage surface receptor, CD74. To evaluate this hypothesis, binding analyses using surface plasmon resonance (Biacore) were carried out. The Kd of MIF was previously approximated to be between 9 × 10-9 to 2.3 × 10-10. Lm1740MIF showed a significant binding interaction with CD74 (Kd=2.9 × 10-8 M). Thus, there is sufficient structural homology between Lm1740MIF and human MIF to permit high-affinity binding to CD74. To investigate whether Lm1740MIF induces ERK1/2 activation in a CD74-dependent manner and to determine if it inhibits activation-induced macrophage apoptosis similar to its mammalian counterpart, the ability of Lm1740MIF to stimulate ERK1/2 phosphorylation as well as to inhibit Ser15 phosphorylation of the tumor suppressor p53 was tested. Macrophages treated with Lm1740MIF were assessed for apoptosis by the ELISA method; additionally, Western blot analyses for ERK1/2 and p53 activation were performed. The interaction between Lm1740MIF and CD74 led to an similar signal transduction response in macrophages obtained from both wild-type and C3H/HeJ mice, indicating that signaling was not due to the presence of contaminating endotoxin. Lm1740MIF was functionally active in both ERK1/2 signaling and protection from apoptosis, although the level of activity was generally lower than for mammalian MIF, an observation that appeared consistent with the lower Kd of Lm1740MIF for the CD74 receptor. For mouse MIF, protection from apoptosis was dependent on CD74, and the response was associated with a decrease in the cytoplasmic content of Ser15-phosphorylated p53. The ability of Lm1740MIF to inhibit apoptosis may facilitate the persistence of Leishmania within macrophages and contribute to its evasion from immune destruction. The precise cellular pathway by which Lm1740MIF activates CD74 and whether Lm1740MIF modulates additional pathways that are important for either intracellular parasitism or for immune evasion remains to be determined. In conclusion, the presented results indicate that a Leishmania ortholog of the cytokine MIF has the ability to activate the human MIF receptor and influence the functional responses of monocytes/macrophages. Because Leishmania is an intracellular infection of monocytes/macrophages, Leishmania-encoded MIF is hypothesized to sustain monocyte/macrophage survival and contribute to the persistence of the parasite for completion of its infectious life cycle. While these data are consistent with a role for Leishmania MIF in modulating host-immune responses, they do not exclude the possibility that Lm1740MIF may function in the growth and/or replication of the parasite