Podocalyxin Is a Novel Polysialylated Neural Adhesion Protein with Multiple Roles in Neural Development and Synapse Formation

Neural development and plasticity are regulated by neural adhesion proteins, including the polysialylated form of NCAM (PSA-NCAM). Podocalyxin (PC) is a renal PSA-containing protein that has been reported to function as an anti-adhesin in kidney podocytes. Here we show that PC is widely expressed in neurons during neural development. Neural PC interacts with the ERM protein family, and with NHERF1/2 and RhoA/G. Experiments in vitro and phenotypic analyses of podxl-deficient mice indicate that PC is involved in neurite growth, branching and axonal fasciculation, and that PC loss-offunction reduces the number of synapses in the CNS and in the neuromuscular system. We also show that whereas some of the brain PC functions require PSA, others depend on PC per se. Our results show that PC, the second highly sialylated neural adhesion protein, plays multiple roles in neural development

The role of clonal communication and heterogeneity in breast cancer

Background: Cancer is a rapidly evolving, multifactorial disease that accumulates numerous genetic and epigenetic alterations. This results in molecular and phenotypic heterogeneity within the tumor, the complexity of which is further amplified through specific interactions between cancer cells. We aimed to dissect the molecular mechanisms underlying the cooperation between different clones. Methods: We produced clonal cell lines derived from the MDA-MB-231 breast cancer cell line, using the UbC-StarTrack system, which allowed tracking of multiple clones by color: GFP C3, mKO E10 and Sapphire D7. Characterization of these clones was performed by growth rate, cell metabolic activity, wound healing, invasion assays and genetic and epigenetic arrays. Tumorigenicity was tested by orthotopic and intravenous injections. Clonal cooperation was evaluated by medium complementation, co-culture and co-injection assays. Results: Characterization of these clones in vitro revealed clear genetic and epigenetic differences that affected growth rate, cell metabolic activity, morphology and cytokine expression among cell lines. In vivo, all clonal cell lines were able to form tumors; however, injection of an equal mix of the different clones led to tumors with very few mKO E10 cells. Additionally, the mKO E10 clonal cell line showed a significant inability to form lung metastases. These results confirm that even in stable cell lines heterogeneity is present. In vitro, the complementation of growth medium with medium or exosomes from parental or clonal cell lines increased the growth rate of the other clones. Complementation assays, co-growth and co-injection of mKO E10 and GFP C3 clonal cell lines increased the efficiency of invasion and migration. Conclusions: These findings support a model where interplay between clones confers aggressiveness, and which may allow identification of the factors involved in cellular communication that could play a role in clonal cooperation and thus represent new targets for preventing tumor progression

Role of the Cellular Prion Protein in Oligodendrocyte Precursor Cell Proliferation and Differentiation in the Developing and Adult Mouse CNS

There are numerous studies describing the signaling mechanisms that mediate oligodendrocyte precursor cell (OPC) proliferation and differentiation, although the contribution of the cellular prion protein (PrPc) to this process remains unclear. PrPc is a glycosyl-phosphatidylinositol (GPI)-anchored glycoprotein involved in diverse cellular processes during the development and maturation of the mammalian central nervous system (CNS). Here we describe how PrPc influences oligodendrocyte proliferation in the developing and adult CNS. OPCs that lack PrPc proliferate more vigorously at the expense of a delay in differentiation, which correlates with changes in the expression of oligodendrocyte lineage markers. In addition, numerous NG2-positive cells were observed in cortical regions of adult PrPc knockout mice, although no significant changes in myelination can be seen, probably due to the death of surplus cells

Sustainable Construction Technologies: Life Cycle Assessment.

The building and construction industry has become the focus of environmental impact reduction in the aftermath of the global resolution to reduce its adverse effect and make the built environment more sustainable. This chapter examines the place of materials in sustainable building construction generally and from the perspective of life cycle assessment and reduction of environmental impact. Hence, specific approaches to sustainable construction from the perspective of materials such as improved material production processes, recycling, materials substitution, innovative construction methods, deconstruction, use of innovative materials, and use of eco-friendly materials are explained from the life cycle impact perspective. The implications of the approaches for improved uptake of sustainable construction practices are also examined with particular reference to the role of policy framework and legislatio

Progenitor potential and cell progeny of NG2-glia

GLIA 67:E125¿E766 (2019) : T02-048BNG2-cells are the most enigmatic neural population, homogenously distributed in a grid-like manner in both gray and white matter regions of the adult brain. In the CNS, a fraction of NG2 cells (OPCs) is responsible for the generation of mature oligodendrocytes, but most of them do not differentiate, representing the most proliferative cells out of the adult neurogenic niches. Fate-mapping analysis in different transgenic mice lines revealed different degrees of differentiation and maturation properties of NG2 cells depending on brain areas. Such diversity suggests that NG2-cells conforms a heterogeneous population composed by different subpopulations devoted to distinct functions. Our hypothesis is that those differences emerge during development as occurs with other glial cell subtypes that are generated from specific progenitors (García-Marques and Lopez-Mascaraque, 2013; 2017). Using a multi-color genetic lineage tracing system, StarTrack, we specifically targeted pallial progenitors, to analyze the type and location of adult labelled cells related to their origin and embryonic stage. Star Track labelled cells exhibited different neural phenotypes and located at different regions that were classified in relation to the targeted embryonic area. Moreover, we also designed different StarTrack strategies to permanently label the individual progenitor cells and their progeny. The plasmids are injected in the lateral ventricles and electroporared in vivo using in utero (IUE) or postnatal electroporation at different stages (E12-P1). First, NG2-EGFP-StarTrack was used to specifically label their cell progeny. Preliminary data showed that labeled cells are located in the gray and white matter, and those cells represent different neural types. Secondly, to specific target the NG2-progenitors we performed the same experiment using Ubc-StarTrack along with an embodying NG2 promoter into the transposase. Preliminary results showed that those progenitors cells labeled with UbC-EGFP-StarTrack constructs are committed to give rise to astrocytes, NG2 cells and even neurons at P90. We expect that our findings will provide fundamental aspects of the lineage potential, cell fate determination and functionality of NG2 cells.Supported by research Grant BFU2016-75207-R from MINEC

Heterogeneity of astrocytes: Electrophysiological properties of juxtavascular astrocytes before and after brain injury.

Astrocyte heterogeneity is increasingly recognized, but still little is known about juxtavascular astrocytes with their somata directly adjacent to blood vessels, despite their importance after brain injury. As juxtavascular astrocytes originate from common progenitor cells, that is, have a clonal origin, they may intrinsically differ from other, non-juxtavascular astrocytes. To explore this, we examined the electrophysiological properties of these groups of astrocytes and the underlying ion channels. Using brain slices of BAC Aldh1l1-eGFP transgenic mice with astrocytes labeled by GFP expression, we compared juxtavascular and non-juxtavascular astrocytes in the somatosensory cortex by means of whole-cell patch-clamp recordings and immunohistochemical staining. Prior to injury, juxta- and non-juxtavascular astrocytes exhibit comparable electrophysiological properties with characteristic mostly passive conductance and a typical negative resting membrane potential. Immunohistochemical analysis of K(+)channels showed that all astrocytes were K(ir)4.1(+), but revealed an intriguing difference for K(v)4.3. The expression of K(v)4.3 in sibling astrocytes (non-juxtavascular, juxtavascular and pial) was dependent on their ontogenetic origin with lowest levels in juxtavascular astrocytes located in upper cortical layers. After traumatic brain injury (TBI), we found profound changes in the electrophysiological type of astrocytes with a predominance of non-passive properties and this pattern was significantly enriched in juxtavascular astrocytes. This was accompanied by pronounced down-regulation of K(ir)4.1 in proliferating astrocytes, which was significantly more in juxtavascular compared to non-juxtavascular astrocytes. Taken together, TBI induces profound differences in electrophysiological properties between juxtavascular and non-juxtavascular astrocytes that might be related to the preponderance of juxtavascular astrocyte proliferation

Neuregulin-1/ErbB4 signaling controls the migration of oligodendrocyte precursor cells during development

During embryonic development, the oligodendrocyte precursors (OPCs) are generated in specific oligodendrogliogenic sites within the neural tube and migrate to colonize the entire CNS. Different factors have been shown to influence the OPC migration and differentiation, including morphogens, growth factors, chemotropic molecules, and extracellular matrix proteins. Neuregulins have been shown to influence the migration of neuronal precursors as well as the movement and differentiation of Schwann cells for peripheral myelination, but their role in the motility of OPCs has not been explored. In the present study, we have used the optic nerve as an experimental model to examine the function of Nrg1 and its ErbB4 receptor in the migration of OPCs in the developing embryo. In vitro experiments revealed that Nrg1 is a potent chemoattractant for the first wave of OPCs, and that this effect is mediated via ErbB4 receptor. In contrast, OPCs colonizing the optic nerve at postnatal stages (PDGFRα +-OPCs) does not respond to Nrg1-chemoattraction. We also found that mouse embryos lacking ErbB4 display deficits in early OPC migration away from different oligodendrogliogenic regions in vivo. The present findings reveal a new role for Nrg1/ErbB4 signaling in regulating OPC migration selectively during early stages of CNS development. © 2012 Elsevier Inc..This work was supported by grants from the Spanish Ministry of Science and Innovation-MICINN (SAF2007-65845, SAF2009-07842), RD07-0060 (European Union, >Una manera de hacer Europa>) and the Government of Castilla-La Mancha (ICS06024/00, PAI08-0242-3822, G-2008-C8) to F.dC., and from MICINN (SAF2008-00770, SAF2009-08049-E and CONSOLIDER CSD2007-00023) to O.M. MCO has a predoctoral fellowship from FISCAM (MOV-2007_JI/20). A.B. has a postdoctoral contract of the >Sara Borrell> program from the FIS-ISCIII/Spanish Ministry of Health. S.P. is an I3P researcher from the Spanish Research Council (CSIC). F.dC. is an employee of the Health Service of Castilla-La Mancha (SESCAM).Peer Reviewe

Developmental Expression of the Oligodendrocyte Myelin Glycoprotein in the Mouse Telencephalon

The oligodendrocyte myelin glycoprotein is a glycosylphosphatidylinositol-anchored protein expressed by neurons and oligodendrocytes in the central nervous system. Attempts have been made to identify the functions of the myelin-associated inhibitory proteins (MAIPs) after axonal lesion or in neurodegeneration. However, the developmental roles of some of these proteins and their receptors remain elusive. Recent studies indicate that NgR1 and the recently discovered receptor PirB restrict cortical synaptic plasticity. However, the putative factors that trigger these effects are unknown. Because Nogo-A is mostly associated with the endoplasmic reticulum and myelin associated glycoprotein appears late during development, the putative participation of OMgp should be considered. Here, we examine the pattern of development of OMgp immunoreactive elements during mouse telencephalic development. OMgp immunoreactivity in the developing cortex follows the establishment of the thalamo-cortical barrel field. At the cellular level, we located OMgp neuronal membranes in dendrites and axons as well as in brain synaptosome fractions and axon varicosities. Lastly, the analysis of the barrel field in OMgp-deficient mice revealed that although thalamo-cortical connections were formed, their targeting in layer IV was altered, and numerous axons ectopically invaded layers II–III. Our data support the idea that early expressed MAIPs play an active role during development and point to OMgp participating in thalamo-cortical connections