Synchronous and symmetric migration of Drosophila caudal visceral mesoderm cells requires dual input by two FGF ligands

Caudal visceral mesoderm (CVM) cells migrate synchronously towards the anterior of the Drosophila embryo as two distinct groups located on each side of the body, in order to specify longitudinal muscles that ensheath the gut. Little is known about the molecular cues that guide cells along this path, the longest migration of embryogenesis, except that they closely associate with trunk visceral mesoderm (TVM). The expression of the fibroblast growth factor receptor (FGFR) heartless and its ligands, pyramus (pyr) and thisbe (ths), within CVM and TVM cells, respectively, suggested FGF signaling may influence CVM cell guidance. In FGF mutants, CVM cells die before reaching the anterior region of the TVM. However, an earlier phenotype observed was that the two cell clusters lose direction and converge at the midline. Live in vivo imaging and tracking analyses identified that the movements of CVM cells were slower and no longer synchronous. Moreover, CVM cells were found to cross over from one group to the other, disrupting bilateral symmetry, whereas such mixing was never observed in wild-type embryos. Ectopic expression of either Pyr or Ths was sufficient to redirect CVM cell movement, but only when the endogenous source of these ligands was absent. Collectively, our results show that FGF signaling regulates directional movement of CVM cells and that native presentation of both FGF ligands together is most effective at attracting cells. This study also has general implications, as it suggests that the activity supported by two FGF ligands in concert differs from their activities in isolation

Spatial and molecular cues for cell outgrowth during C. elegans uterine development

The Caenorhabditis elegans uterine seam cell (utse) is an H-shaped syncytium that connects the uterus to the body wall. Comprising nine nuclei that move outward in a bidirectional manner, this synctium undergoes remarkable shape change during development. Using cell ablation experiments, we show that three surrounding cell types affect utse development: uterine toroids, the anchor cell and the sex myoblasts. The presence of the anchor cell (AC) nucleus within the utse is necessary for proper utse development and AC invasion genes fos-1, cdh-3, him-4, egl-43, zmp-1 and mig-10 promote utse cell outgrowth. Two types of uterine lumen epithelial cells, uterine toroid 1 (ut1) and uterine toroid 2 (ut2), mediate proper utse outgrowth and we show roles in utse development two genes expressed in the uterine toroids: RASEF ortholog rsef-1 and Trio/unc-73. The SM expressed gene unc-53/NAV regulates utse cell shape; ablation of sex myoblasts (SMs), which generate uterine and vulval muscles, cause defects in utse morphology. Our results clarify the nature of the interactions that exist between utse and surrounding tissue, identify new roles for genes involved in cell outgrowth, and present the utse as a new model system for understanding cell shape change and, putatively, diseases associated with cell shape change

The immune checkpoint molecules PD-1, PD-L1, TIM-3 and LAG-3 in diffuse large B-cell lymphoma

Signaling through immune checkpoint receptors may lead to T-cell exhaustion and function as immune escape mechanisms in cancer. For diffuse large B-cell lymphoma (DLBCL), the mechanistic and prognostic importance of these markers on tumor cells and the tumor microenvironment remains unclear. We determined the immunohistochemical expression of PD-1, PD-L1, TIM-3, and LAG-3 on tumor cells and on tumor infiltrating lymphocytes (TILs) among 123 DLBCL patients. TIM-3 showed positive staining on tumor cells in 39% of DLBCL cases and PD-L1 expression was noted in 15% of cases. Both PD-1 and LAG-3 were positive on tumor cells in a minority of DLBCL cases (8.3% and 7.5%, respectively), but were more widely expressed on TILs in a correlated manner. With median follow-up of 44 months (n = 70, range 5-85), 4-year progression-free survival (PFS) and overall survival (OS) rates were significantly inferior among DLBCL patients with high vs low/negative TIM-3 expression (PFS: 23% [95% CI 7% to 46%] vs 60% [95% CI 43% to 74%], respectively, P = 0.008; OS: 30% [95% CI 10% to 53%] vs 74% [95% CI 58% to 85%], respectively, P = 0.006). Differences in OS remained significant when controlling for International Prognostic Index in Cox regression analyses (HR 3.49 [95% CI 1.40-6.15], P = 0.007). In addition, we observed that co-culture of DLBCL cell lines with primed T cells in the presence of anti-LAG-3 and anti-TIM-3 induced potent dose-dependent increases in in vitro cell death via AcellaTox and IL-2 ELISA assays, suggesting potent anti-tumor activity of these compounds

Novel Microbial System Developed from Low-Level Radioactive Waste Treatment Plant for Environmental Sustenance

A packed bed bioreactor efficiently treated low-level radioactive waste for years with a retention time of 24 h using acetate as the sole carbon source. However, there was generation of dead biomass. This bioreactor biomass was used to develop a bacterial consortium, which could perform the function within 4 h while simultaneously accumulating nitrate and phosphate. The dead mass was negligible. Serial dilution technique was used to isolate the world’s first pure culture of a nitrate accumulating strain from this consortium. This isolate could simultaneously accumulate nitrate and phosphate from solution. Its ability to form biofilm helped develop a packed bed bioreactor system for waste water treatment, which could optimally remove 94.46% nitrate within 11 h in batch mode while 8 h in continuous mode from waste water starting from 275 ppm of nitrate. The conventional approach revealed the strain to be a member of genus Bacillus but showed distinct differences with the type strains. Further insilico analysis of the draft genome and the putative protein sequences using the bioinformatics tools revealed the strain to be a novel variant of genus Bacillus. The sequestered nitrate and phosphate within the cell were visualized through electron microscopy and explained the reason behind the ability of the isolate to accumulate 1.12 mg of phosphate and 1.3 gm of nitrate per gram of wet weight. Transcriptome analysis proposed the mechanism behind the accumulation of nitrate and phosphate in case of this novel bacterial isolate (MCC 0008). The strain with the sequestered nutrients work as biofertilizer for yield enhancement in case of mung bean while maintaining soil fertility post-cultivation

Microbe-Based Strategy for Plant Nutrient Management

The rapid industrialization and urbanization of developing countries such as India have encroached on cultivable lands to meet the demands of an ever-increasing population. The altered land use patterns with increased fertilizer use has increased crop yields with leaching of major portion of the applied nutrients from the soil. Nitrates and phosphates are the agricultural pollutants that are discharged into aquifers due to anthropogenic reasons causing severe environmental and health problems. Production of these nutrients requires energy and finite resources (rock phosphate, which has gradually depleting reserves). An alternative management strategy would be to sequester excess nutrients within a biomass that is reused for agriculture. Two discrete enriched microbial consortia with the potential of simultaneous nitrate and phosphate sequestration upon application as biofertilizer restricted them within the plant root zone, ensuring prevention of eutrophication through leaching while making it available for uptake by plants. The nutrient accumulated biomass enhanced the crop yield by 21.88% during mung bean cultivation with maintained elemental content and other nutritional qualities. The major drawback of conventional biofertilizer application (slow release and action) could be overcome using this formulation leading to environmental protection, crop yield enhancement and soil fertility maintenance post-cultivation

Planar Cell Polarity Acts Through Septins to Control Collective Cell Movement and Ciliogenesis

The planar cell polarity (PCP) signaling pathway governs collective cell movements during vertebrate embryogenesis, and certain PCP proteins are also implicated in the assembly of cilia. The septins are cytoskeletal proteins controlling behaviors such as cell division and migration. Here, we identified control of septin localization by the PCP protein Fritz as a crucial control point for both collective cell movement and ciliogenesis in Xenopus embryos. We also linked mutations in human Fritz to Bardet-Biedl and Meckel-Gruber syndromes, a notable link given that other genes mutated in these syndromes also influence collective cell movement and ciliogenesis. These findings shed light on the mechanisms by which fundamental cellular machinery, such as the cytoskeleton, is regulated during embryonic development and human disease

The role of the PCP effector protein Fritz in convergent extension, ciliogenesis and hedgehog signaling

Fritz is one of the downstream players in the Planar Cell Polarity (PCP) pathway. PCP signaling was first identified in Drosophila, and many vertebrate homologues of PCP genes have been shown to be central to neural tube development and closure in vertebrate animals, including humans. Recently, it has also been shown that some PCP genes are involved in the formation of cilia. A critical function for cilia during embryonic development involves transducing Hedgehog signaling, which is essential for neural tube closure. However, the role of Fritz in vertebrate neural tube formation has not yet been studied. The expression patterns of Fritz during the early development of Xenopus laevis embryos have been determined. Also, phenotypic changes in Xenopus laevis embryos have been observed when the Fritz protein is knocked down by antisense morpholino oligonucleotide injection— embryos failed to close their neural tube properly, indicating that Fritz is involved in neural tube closure as well as convergent extension. GFP fusion to Fritz and immunostaining reveal that Fritz protein is localized at the base of cilia. Morpholino injection resulted in defective cilia inside the neural tube and in the epidermis of these morphant embryos. These results indicated that Fritz is an essential gene for cilia formation. Furthermore, the expression level of Hedgehog target genes was greatly reduced within Fritz morphants. Fritz morphants also exhibit characteristic craniofacial defects associated with defective Hedgehog signaling. Though much work is left to determine the exact role of Fritz, these experiments illustrate that the Fritz gene is involved in cilia formation, and consequently Hedgehog signaling, which is critical for neural tube closure and development in vertebrate animals. Neural tube closure and Hedgehog signaling are two processes that are essential for proper vertebrate development. The neural tube later gives rise to the brain and spinal cord, while Hedgehog signaling is necessary for brain development, limb development, and establishment of the midline. Considering that Fritz plays a role in both of these processes, a better understanding of Fritz can provide vital information about early vertebrate development. More importantly, because a lack of Fritz disrupts these processes, one can gain insight into why certain developmental defects occur. These include Holoprosencephaly, which results in severe defects in brain formation, and Spina Bifida, a spinal cord formation defect that is one of the most common birth defects worldwide. It is my hope that my work on Fritz has contributed to the body of knowledge regarding these types of defects, and that my work may be someday used to help prevent or treat these defects, and save the lives of children worldwide.Biological Sciences, School o

Establishing the C. elegans Uterine Seam Cell (utse) as a Novel Model for Studying Cell Behavior

The molecular inputs necessary for cell behavior are vital to our understanding of development and disease. Proper cell behavior is necessary for processes ranging from creating one’s face (neural crest migration) to spreading cancer from one tissue to another (invasive metastatic cancers). Identifying the genes and tissues involved in cell behavior not only increases our understanding of biology but also has the potential to create targeted therapies in diseases hallmarked by aberrant cell behavior. A well-characterized model system is key to determining the molecular and spatial inputs necessary for cell behavior. In this work I present the C. elegans uterine seam cell (utse) as an ideal model for studying cell outgrowth and shape change. The utse is an H-shaped cell within the hermaphrodite uterus that functions in attaching the uterus to the body wall. Over L4 larval stage, the utse grows bidirectionally along the anterior-posterior axis, changing from an ellipsoidal shape to an elongated H-shape. Spatially, the utse requires the presence of the uterine toroid cells, sex muscles, and the anchor cell nucleus in order to properly grow outward. Several gene families are involved in utse development, including Trio, Nav, Rab GTPases, Arp2/3, as well as 54 other genes found from a candidate RNAi screen. The utse can be used as a model system for studying metastatic cancer. Meprin proteases are involved in promoting invasiveness of metastatic cancers and the meprin-likw genes nas-21, nas-22, and toh-1 act similarly within the utse. Studying nas-21 activity has also led to the discovery of novel upstream inhibitors and activators as well as targets of nas-21, some of which have been characterized to affect meprin activity. This illustrates that the utse can be used as an in vivo model for learning more about meprins, as well as various other proteins involved in metastasis.</p

Non-neuronal cell outgrowth in C. elegans

Cell outgrowth is a hallmark of some non-migratory developing cells during morphogenesis. Understanding the mechanisms that control cell outgrowth not only increases our knowledge of tissue and organ development, but can also shed light on disease pathologies that exhibit outgrowth-like behavior. C. elegans is a highly useful model for the analysis of genes and the function of their respective proteins. In addition, C. elegans also has several cells and tissues that undergo outgrowth during development. Here we discuss the outgrowth mechanisms of nine different C. elegans cells and tissues. We specifically focus on how these cells and tissues grow outward and the interactions they make with their environment. Through our own identification, and a meta-analysis, we also identify gene families involved in multiple cell outgrowth processes, which defined potential C. elegans core components of cell outgrowth, as well as identify a potential stepwise cell behavioral cascade used by cells undergoing outgrowth