scholarly journals Bayes-Optimal Chemotaxis

2011 ◽  
Vol 23 (2) ◽  
pp. 336-373 ◽  
Author(s):  
Duncan Mortimer ◽  
Peter Dayan ◽  
Kevin Burrage ◽  
Geoffrey J. Goodhill

Chemotaxis plays a crucial role in many biological processes, including nervous system development. However, fundamental physical constraints limit the ability of a small sensing device such as a cell or growth cone to detect an external chemical gradient. One of these is the stochastic nature of receptor binding, leading to a constantly fluctuating binding pattern across the cell's array of receptors. This is analogous to the uncertainty in sensory information often encountered by the brain at the systems level. Here we derive analytically the Bayes-optimal strategy for combining information from a spatial array of receptors in both one and two dimensions to determine gradient direction. We also show how information from more than one receptor species can be optimally integrated, derive the gradient shapes that are optimal for guiding cells or growth cones over the longest possible distances, and illustrate that polarized cell behavior might arise as an adaptation to slowly varying environments. Together our results provide closed-form predictions for variations in chemotactic performance over a wide range of gradient conditions.

2021 ◽  
Vol 15 ◽  
Author(s):  
Marta Tiberi ◽  
Valerio Chiurchiù

Astrocytes and oligodendrocytes are known to play critical roles in the central nervous system development, homeostasis and response to injury. In addition to their well-defined functions in synaptic signaling, blood-brain barrier control and myelination, it is now becoming clear that both glial cells also actively produce a wide range of immune-regulatory factors and engage in an intricate communication with neurons, microglia or with infiltrated immune cells, thus taking a center stage in both inflammation and resolution processes occurring within the brain. Resolution of inflammation is operated by the superfamily of specialized pro-resolving lipid mediators (SPMs), that include lipoxins, resolvins, protectins and maresins, and that altogether activate a series of cellular and molecular events that lead to spontaneous regression of inflammatory processes and restoration of tissue homeostasis. Here, we review the manifold effects of SPMs on modulation of astrocytes and oligodendrocytes, along with the mechanisms through which they either inhibit inflammatory pathways or induce the activation of protective ones. Furthermore, the possible role of SPMs in modulating the cross-talk between microglia, astrocytes and oligodendrocytes is also summarized. This SPM-mediated mechanism uncovers novel pathways of immune regulation in the brain that could be further exploited to control neuroinflammation and neurodegeneration.


Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 711-722 ◽  
Author(s):  
T.E. Rusten ◽  
R. Cantera ◽  
J. Urban ◽  
G. Technau ◽  
F.C. Kafatos ◽  
...  

Genes of the spalt family encode nuclear zinc finger proteins. In Drosophila melanogaster, they are necessary for the establishment of head/trunk identity, correct tracheal migration and patterning of the wing imaginal disc. Spalt proteins display a predominant pattern of expression in the nervous system, not only in Drosophila but also in species of fish, mouse, frog and human, suggesting an evolutionarily conserved role for these proteins in nervous system development. Here we show that Spalt works as a cell fate switch between two EGFR-induced cell types, the oenocytes and the precursors of the pentascolopodial organ in the embryonic peripheral nervous system. We show that removal of spalt increases the number of scolopodia, as a result of extra secondary recruitment of precursor cells at the expense of the oenocytes. In addition, the absence of spalt causes defects in the normal migration of the pentascolopodial organ. The dual function of spalt in the development of this organ, recruitment of precursors and migration, is reminiscent of its role in tracheal formation and of the role of a spalt homologue, sem-4, in the Caenorhabditis elegans nervous system.


2002 ◽  
Vol 5 (4) ◽  
pp. 329-349 ◽  
Author(s):  
Donald Newgreen ◽  
Heather M. Young

This review, which is presented in two parts, summarizes and synthesizes current views on the genetic, molecular, and cell biological underpinnings of the early embryonic phases of enteric nervous system (ENS) formation and its defects. Accurate descriptions of the phenotype of ENS dysplasias, and knowledge of genes which, when mutated, give rise to the disorders (see Part 1 in the previous issue of this journal), are not sufficient to give a real understanding of how these abnormalities arise. The often indirect link between genotype and phenotype must be sought in the early embryonic development of the ENS. Therefore, in this, the second part, we provide a description of the development of the ENS, concentrating mainly on the origin of the ENS precursor cells and on the cell migration by which they become distributed throughout the gastrointestinal tract. This section also includes experimental evidence on the controls of ENS formation derived from classic embryological, cell culture, and molecular genetic approaches. In addition, for reasons of completeness, we also briefly describe the origins of the interstitial cells of Cajal, a cell population closely related anatomically and functionally to the ENS. Finally, a brief sketch is presented of current notions on the developmental processes between the genes and the morphogenesis of the ENS, and of the means by which the known genetic abnormalities might result in the ENS phenotype observed in Hirschsprung's disease.


2021 ◽  
Author(s):  
Carlos Rivera ◽  
Daniel Verbel ◽  
Duxan Arancibia ◽  
Anna Lappala ◽  
Marcela González ◽  
...  

Abstract Background Nuclear processes such as transcription and RNA maturation can be impacted by subnuclear compartmentalization in condensates and nuclear bodies. Here we characterize the nature of nuclear granules formed by REST corepressor 2 (RCOR2), a nuclear protein essential for pluripotency maintenance and central nervous system development. Results Using biochemical approaches and high-resolution microscopy, we reveal that RCOR2 is localized in nuclear speckles across multiple cell types, including neurons in the brain. RCOR2 forms complexes with nuclear speckle components such as SON, SRSF7, and SRRM2. When cells are exposed to chemical stress, RCOR2 behaves as a core component of the nuclear speckle and is stabilized by RNA. In turn, nuclear speckle morphology appears to depend on RCOR2. Specifically, RCOR2 knockdown results larger nuclear speckles, whereas overexpressing RCOR2 leads to smaller and rounder nuclear speckles. Conclusion Our study suggests that RCOR2 is a regulatory component of the nuclear speckle bodies, setting this co-repressor protein as a factor that controls nuclear speckles behavior.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Carlos Rivera ◽  
Daniel Verbel-Vergara ◽  
Duxan Arancibia ◽  
Anna Lappala ◽  
Marcela González ◽  
...  

Abstract Background Nuclear processes such as transcription and RNA maturation can be impacted by subnuclear compartmentalization in condensates and nuclear bodies. Here, we characterize the nature of nuclear granules formed by REST corepressor 2 (RCOR2), a nuclear protein essential for pluripotency maintenance and central nervous system development. Results Using biochemical approaches and high-resolution microscopy, we reveal that RCOR2 is localized in nuclear speckles across multiple cell types, including neurons in the brain. RCOR2 forms complexes with nuclear speckle components such as SON, SRSF7, and SRRM2. When cells are exposed to chemical stress, RCOR2 behaves as a core component of the nuclear speckle and is stabilized by RNA. In turn, nuclear speckle morphology appears to depend on RCOR2. Specifically, RCOR2 knockdown results larger nuclear speckles, whereas overexpressing RCOR2 leads to smaller and rounder nuclear speckles. Conclusion Our study suggests that RCOR2 is a regulatory component of the nuclear speckle bodies, setting this co-repressor protein as a factor that controls nuclear speckles behavior.


2015 ◽  
Vol 9s2 ◽  
pp. JEN.S25480 ◽  
Author(s):  
Ana Ana Maria ◽  
Moreno-Ramos Oscar Andréas ◽  
Neena B. Haider

The nuclear hormone receptor (NHR) superfamily is composed of a wide range of receptors involved in a myriad of important biological processes, including development, growth, metabolism, and maintenance. Regulation of such wide variety of functions requires a complex system of gene regulation that includes interaction with transcription factors, chromatin-modifying complex, and the proper recognition of ligands. NHRs are able to coordinate the expression of genes in numerous pathways simultaneously. This review focuses on the role of nuclear receptors in the central nervous system and, in particular, their role in regulating the proper development and function of the brain and the eye. In addition, the review highlights the impact of mutations in NHRs on a spectrum of human diseases from autism to retinal degeneration.


2007 ◽  
Vol 3 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Patrick Cafferty ◽  
Vanessa J. Auld

AbstractGlial cells play a wide range of essential roles in both nervous system development and function and has been reviewed recently (Parker and Auld, 2006). Glia provide an insulating sheath, either form or direct the formation of the blood–brain barrier, contribute to ion and metabolite homeostasis and provide guidance cues. Glial function often depends on the ability of glial cells to migrate toward specific locations during nervous system development. Work in nervous system development in insects, in particular in the fruit fly Drosophila melanogaster and the tobacco hornworm Manduca sexta, has provided significant insight into the roles of glia, although the molecular mechanisms underlying glial cell migration are being determined only now. Indeed, many of the processes and mechanisms discovered in these simpler systems have direct parallels in the development of vertebrate nervous systems. In this review, we first examine the developmental contexts in which invertebrate glial cell migration has been observed, we next discuss the characterized molecules required for proper glial cell migration, and we finally discuss future goals to be addressed in the study of glial cell development.


Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3513-3522 ◽  
Author(s):  
Silvia Marino ◽  
Paul Krimpenfort ◽  
Carly Leung ◽  
Hetty A. G. M. van der Korput ◽  
Jan Trapman ◽  
...  

PTEN is a tumour suppressor gene involved in cell cycle control, apoptosis and mediation of adhesion and migration signalling. Germline mutations of PTEN in humans are associated with familial tumour syndromes, among them Cowden disease. Glioblastomas, highly malignant glial tumours of the central nervous system frequently show loss of PTEN. Recent reports have outlined some aspects of PTEN function in central nervous system development. Using a conditional gene disruption approach, we inactivated Pten in mice early during embryogenesis locally in a region specific fashion and later during postnatal development in a cell-specific manner, to study the role of PTEN in differentiation, migration and neoplastic transformation. We show that PTEN is required for the realisation of normal cerebellar architecture, for regulation of cell and organ size, and for proper neuronal and glial migration. However, PTEN is not required for cell differentiation and lack of PTEN is not sufficient to induce neoplastic transformation of neuronal or glial cells


2017 ◽  
Vol 312 (6) ◽  
pp. C673-C686 ◽  
Author(s):  
Jeppe Praetorius ◽  
Helle Hasager Damkier

The choroid plexus epithelium is a secretory epithelium par excellence. However, this is perhaps not the most prominent reason for the massive interest in this modest-sized tissue residing inside the brain ventricles. Most likely, the dominant reason for extensive studies of the choroid plexus is the identification of this epithelium as the source of the majority of intraventricular cerebrospinal fluid. This finding has direct relevance for studies of diseases and conditions with deranged central fluid volume or ionic balance. While the concept is supported by the vast majority of the literature, the implication of the choroid plexus in secretion of the cerebrospinal fluid was recently challenged once again. Three newer and promising areas of current choroid plexus-related investigations are as follows: 1) the choroid plexus epithelium as the source of mediators necessary for central nervous system development, 2) the choroid plexus as a route for microorganisms and immune cells into the central nervous system, and 3) the choroid plexus as a potential route for drug delivery into the central nervous system, bypassing the blood-brain barrier. Thus, the purpose of this review is to highlight current active areas of research in the choroid plexus physiology and a few matters of continuous controversy.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Sehua Qu ◽  
Lianqiang Shan ◽  
Zhen Zhang ◽  
Wansheng Peng ◽  
Yun Chen ◽  
...  

In order to explore the prediction effect of amplitude-integrated EEG on the brain damage and long-term nervous system development of late preterm infants, this paper uses the hospital’s late preterm infants as the research object and analyzes the prediction effect of amplitude-integrated EEG on the brain damage and long-term nervous system development of late preterm infants through controlled trials. Among them, the test group used amplitude-integrated EEG for prediction analysis, and the control group used traditional clinical prediction methods. Furthermore, the real-time monitoring and short-term prediction effects of amplitude-integrated EEG on brain damage in late preterm babies and the prediction impact on long-term nervous system development are evaluated in this study. It incorporates statistical techniques to evaluate the findings statistically. In addition, a nonparametric rank-sum test is used in this work, and a chi-square test is used to compare enumeration data across groups. Through experimental research, it can be seen that the amplitude-integrated EEG has a pronounced prediction effect on the brain damage and long-term nervous system development of late preterm infants, and the effect is higher than that of the traditional clinical prediction methods.


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