Taurine promotes the differentiation of a vertebrate retinal cell type in vitro

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1317-1328 ◽  
Author(s):  
D. Altshuler ◽  
J.J. Lo Turco ◽  
J. Rush ◽  
C. Cepko
Keyword(s):  
Conditioned Medium ◽  
Control Cell ◽  
Retinal Cell ◽  
Rod Photoreceptor ◽  
Cell Type ◽  
Retinal Explants ◽  
Development In Vitro ◽  
Photoreceptor Development

The retina offers a model system for investigating the mechanisms that control cell type determination and differentiation in the vertebrate central nervous system. Previously, rod photoreceptor development in vitro was found to require a diffusible activity released by retinal cells (D. Altshuler and C. Cepko, Development 114, 947–957, 1992). In this report, we show that retinal-cell-conditioned medium and extracts contain two separable activities that influence rod development: a > 10 kDa inhibitory activity, and a stimulatory activity that is < 1 kDa and heat stable. Taurine was found to be a component of the < 1 kDa fraction and to stimulate rod development when added to retinal cultures. Taurine was not the only rod-promoting factor in these retinal preparations, however, as conditioned medium and extracts stimulated a higher level of rod development than did taurine alone. Taurine uptake into cells could be blocked without inhibiting taurine's ability to stimulate rod development, arguing against an osmoregulatory or nutritive mechanism of action. Finally, a competitive antagonist of taurine's bioactivity was identified and shown partially to inhibit rod development in retinal explants, suggesting that taurine may normally act to stimulate rod development in the retina. These results provide evidence for three activities, one of which is taurine, that are candidate regulators of rod photoreceptor development in vivo.

A temporally regulated, diffusible activity is required for rod photoreceptor development in vitro

Development ◽  
1992 ◽  
Vol 114 (4) ◽  
pp. 947-957 ◽  
Author(s):  
D. Altshuler ◽  
C. Cepko
Keyword(s):  
Cell Fate ◽  
Rod Photoreceptor ◽  
Cell Type ◽  
Retinal Neuron ◽  
Development In Vitro ◽  
Temporally Correlated ◽  
Photoreceptor Development

The retina is a relatively simple and well-characterized CNS structure in which cell-cell interactions have been hypothesized to influence cell type determination. By manipulating cell density in serum-free cultures we show that rat rod photoreceptor development requires a diffusible activity produced by neonatal retinal cells. This effect is not mediated by changes in cell survival or mitosis. Production of the rod promoting activity varies with developmental stage and is temporally correlated with the timing of rod generation in vivo. In low density cultures, which do not support rod development, an increased fraction of cells stain with an antibody specific for another retinal neuron, the bipolar cell. Thus, the diffusible rod promoting activity may influence cell fate determination, and not only terminal differentiation. These results provide an approach for the molecular characterization of developmentally important signals in the vertebrate retina.

Diversity of neuronal phenotypes expressed in monolayer cultures from immature rabbit retina

1994 ◽  
Vol 11 (4) ◽  
pp. 629-642 ◽  
Author(s):  
V. Möckel ◽  
S. Löhrke ◽  
H.-D. Hofmann
Keyword(s):  
Amacrine Cells ◽  
Cell Number ◽  
Retinal Cell ◽  
Gaba Uptake ◽  
Cell Type ◽  
Quisqualic Acid ◽  
Monolayer Cultures ◽  
Dendritic Fields

AbstractWe have used monolayer cultures prepared from early postnatal rabbit retinae (days 2–5) by the sandwich technique to study the capacity of immature neurons to express specific neuronal phenotypes in a homogeneous in vitro environment. Applying morphological, immunocytochemical, and autoradiographic criteria, we demonstrate that a variety of phenotypes could be distinguished after 7–14 days in vitro, and correlated with known retinal cell types. Bipolar cell-like neurons (approximately 4% of total cell number) were identified by cell type-specific monoclonal antibodies (115A10) and their characteristic bipolar morphology. Small subpopulations (about 1%) of GABA-immunoreactive neurons acquired elaborate morphologies strikingly similar to those of A- and B-type horizontal cells. Amongst putative amacrine cells several different subpopulations could be classified. GABA-immunoreactive amacrine-like neurons (6.5%), which also showed high affinity [3H]-GABA uptake, comprised cells of varying size and shape and could be subdivided into subpopulations with respect to their response to different glutamate receptor agonists (NMDA, kainic acid, quisqualic acid). In addition, a small percentage of [3H]-GABA accumulating cells with large dendritic fields showed tyrosine-hydroxylase immunoreactivity. Presumptive glycinergic amacrine cells (18.5%) were rather uniform in shape and had small dendritic fields. Release of [3H]-glycine from these neurons was evoked by kainic and quisqualic acid but not by NMDA. Small [3H]-glutamate accumulating neurons with few short processes were the most frequent cell type (73%). This cell type also exhibited opsin immunoreactivity and probably represented incompletely differentiated photoreceptor cells. Summing the numbers of characterized cells indicated that we were able to attribute a defined retinal phenotype to most, if not all of the cultured neurons. Thus, we have demonstrated that immature neuronal cells growing in monolayer cultures, in the absence of a structured environment, are capable of maintaining or producing specific morphological and functional properties corresponding to those expressed in vivo. These results stress the importance of intrinsic factors for the regulation of neuronal differentiation. On the other hand, morphological differentiation was far from perfect indicating the requirement for regulatory factors.

Ciliary neurotrophic factor promotes chick photoreceptor development in vitro

Development ◽  
1995 ◽  
Vol 121 (8) ◽  
pp. 2695-2706 ◽  
Author(s):  
S. Fuhrmann ◽  
M. Kirsch ◽  
H.D. Hofmann
Keyword(s):  
Growth Factor ◽  
Neurotrophic Factor ◽  
Ciliary Neurotrophic Factor ◽  
Rod Photoreceptor ◽  
Opsin Expression ◽  
Chick Retina ◽  
Continuous Presence ◽  
Development In Vitro ◽  
Photoreceptor Development

Previous in vitro studies have convincingly demonstrated the involvement of diffusible factors in the regulation of photoreceptor development. We now provide evidence that ciliary neurotrophic factor (CNTF) represents one of these regulatory molecules. In low density monolayer cultures prepared from embryonic day 8 chick retina, photoreceptor development was studied using the monoclonal antiopsin antibody rho-4D2 as a differentiation marker. The number of cells acquiring opsin immunoreactivity, determined after 3 days in vitro, was increased up to 4-fold in the presence of CNTF to maximally 10.5% of all cells. Basic fibroblast growth factor or taurine both of which have been reported to stimulate opsin expression in rat retinal cultures and other neurotrophic factors tested (nerve growth factor, brain derived neurotrophic factor) had no effect. The EC50 of the CNTF effect (2.6 pM) was virtually identical to that measured for other CNTF receptor mediated cellular responses. Conditioned medium produced by cultured retinal cells (most likely glial cells) exhibited opsin stimulating activity identical to that of CNTF. Stimulation of opsin expression was specific for morphologically less mature photoreceptors and obviously restricted to rods, since changes in the number of identifiable cone photoreceptors expressing opsin immunoreactivity (10% of all cones) were not detectable. Measurement of the kinetics of the CNTF response revealed that the factor acted on immature opsin-negative progenitors and that CNTF effects were unlikely to reflect enhanced cell survival. Proliferation of photoreceptors was also unaffected, as demonstrated by [3H]thymidine autoradiography. With prolonged culture periods a gradual decrease in the number of opsin-positive cells was observed both in controls and in the continuous presence of CNTF. This decrease could be partly prevented by the addition of 1 mM taurine. Our results suggest that CNTF acted as an inductive signal for uncommitted progenitor cells or during early stages of rod photoreceptor differentiation, whereas other extrinsic stimulatory activities seemed to be required for further maturation.

Cell guidance by ultrafine topography in vitro

1991 ◽  
Vol 99 (1) ◽  
pp. 73-77 ◽  
Author(s):  
P. Clark ◽  
P. Connolly ◽  
A.S. Curtis ◽  
J.A. Dow ◽  
C.D. Wilkinson
Keyword(s):  
Chick Embryo ◽  
Mdck Cells ◽  
Control Cell ◽  
Cell Type ◽  
Cell Behaviour ◽  
The Past ◽  
Microelectronic Fabrication ◽  
Laser Holography

Laser holography and microelectronic fabrication techniques have been employed to make grating surfaces in fused quartz with ultrafine period (260 nm) in an attempt to mimic the topography of aligned fibrillar extracellular matrix (ECM), which, in the past, has been shown to affect the behaviour of cells in vitro and in vivo. The alignment of BHK cells, MDCK cells and chick embryo cerebral neurones on 260 nm period grating surfaces (130 nm grooves separated by 130 nm) of various depths (100, 210 and 400 nm) was examined. While all gratings aligned BHK cell populations, the degree of alignment was dependent on depth. The response of single MDCK cells to the grating patterns was both to align precisely to the direction of the gratings, and to elongate; only their elongation was depth-dependent. MDCK cells that were part of epithelial cell islands, and the outgrowth of neurites from chick embryo neurones, were mainly unaffected by the grating surfaces. It is clear that topography on this scale can control cell behaviour, but guidance of this type is strongly dependent on cell type and cell-cell interactions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

iTSP-PseAAC: Identify Tumor Suppressor Proteins by Using Fully Connected Neural Network and PseAAC

2021 ◽  
Vol 15 ◽  
Author(s):  
Muhammad Awais ◽  
Waqar Hussain ◽  
Nouman Rasool ◽  
Yaser Daanial Khan
Keyword(s):  
Tumor Suppressor ◽  
Cross Validation ◽  
Control Cell ◽  
Normal Function ◽  
In Vivo Studies ◽  
Tumor Suppressor Proteins ◽  
Proposed Model ◽  
Self Consistency

Background: The uncontrolled growth due to accumulation of genetic and epigenetic changes as a result of loss or reduction in the normal function of Tumor Suppressor Genes (TSGs) and Pro-oncogenes is known as cancer. TSGs control cell division and growth by repairing of DNA mistakes during replication and restrict the unwanted proliferation of a cell or activities, those are the part of tumor production. Objectives: This study aims to propose a novel, accurate, user-friendly model to predict tumor suppressor proteins, which would be freely available to experimental molecular biologists to assist them using in vitro and in vivo studies. Methods: The predictor model has used the input feature vector (IFV) calculated from the physicochemical properties of proteins based on FCNN to compute the accuracy, sensitivity, specificity, and MCC. The proposed model was validated against different exhaustive validation techniques i.e. self-consistency and cross-validation. Results: Using self-consistency, the accuracy is 99%, for cross-validation and independent testing has 99.80% and 100% accuracy respectively. The overall accuracy of the proposed model is 99%, sensitivity value 98% and specificity 99% and F1-score was 0.99. Conclusion: It concludes, the proposed model for prediction of the tumor suppressor proteins can predict the tumor suppressor proteins efficiently, but it still has space for improvements in computational ways as the protein sequences may rapidly increase, day by day.

scholarly journals Conditioned medium-preconditioned EPCs enhanced the ability in oligovascular repair in cerebral ischemia neonatal rats

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ning Zhou ◽  
Lei Wang ◽  
Ping Fu ◽  
Zihao Cui ◽  
Yuhang Ge ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Western Blot ◽  
Conditioned Medium ◽  
Cognitive Outcome ◽  
Adult Brain ◽  
Neonatal Rat ◽  
Vascular Density ◽  
Cxcr4 Axis

Abstract Background Oligovascular niche mediates interactions between cerebral endothelial cells and oligodendrocyte precursor cells (OPCs). Disruption of OPC-endothelium trophic coupling may aggravate the progress of cerebral white matter injury (WMI) because endothelial cells could not provide sufficient support under diseased conditions. Endothelial progenitor cells (EPCs) have been reported to ameliorate WMI in the adult brain by boosting oligovascular remodeling. It is necessary to clarify the role of the conditioned medium from hypoxic endothelial cells preconditioned EPCs (EC-pEPCs) in WMI since EPCs usually were recruited and play important roles under blood-brain barrier disruption. Here, we investigated the effects of EC-pEPCs on oligovascular remodeling in a neonatal rat model of WMI. Methods In vitro, OPC apoptosis induced by the conditioned medium from oxygen-glucose deprivation-injured brain microvascular endothelial cells (OGD-EC-CM) was analyzed by TUNEL and FACS. The effects of EPCs on EC damage and the expression of cytomokine C-X-C motif ligand 12 (CXCL12) were examined by western blot and FACS. The effect of the CM from EC-pEPCs against OPC apoptosis was also verified by western blot and silencing RNA. In vivo, P3 rat pups were subjected to right common carotid artery ligation and hypoxia and treated with EPCs or EC-pEPCs at P7, and then angiogenesis and myelination together with cognitive outcome were evaluated at the 6th week. Results In vitro, EPCs enhanced endothelial function and decreased OPC apoptosis. Meanwhile, it was confirmed that OGD-EC-CM induced an increase of CXCL12 in EPCs, and CXCL12-CXCR4 axis is a key signaling since CXCR4 knockdown alleviated the anti-apoptosis effect of EPCs on OPCs. In vivo, the number of EPCs and CXCL12 protein level markedly increased in the WMI rats. Compared to the EPCs, EC-pEPCs significantly decreased OPC apoptosis, increased vascular density and myelination in the corpus callosum, and improved learning and memory deficits in the neonatal rat WMI model. Conclusions EC-pEPCs more effectively promote oligovascular remodeling and myelination via CXCL12-CXCR4 axis in the neonatal rat WMI model.

scholarly journals Lankesterella (Apicomplexa, Lankesterellidae) Blood Parasites of Passeriform Birds: Prevalence, Molecular and Morphological Characterization, with Notes on Sporozoite Persistence In Vivo and Development In Vitro

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1451
Author(s):  
Carolina Romeiro Fernandes Chagas ◽  
Josef Harl ◽  
Vytautas Preikša ◽  
Dovilė Bukauskaitė ◽  
Mikas Ilgūnas ◽  
...  
Keyword(s):  
Morphological Characterization ◽  
Life Cycles ◽  
Diagnostic Methods ◽  
Host Cells ◽  
Blood Parasites ◽  
Serinus Canaria ◽  
Long Time ◽  
Development In Vitro

Recent studies confirmed that some Hepatozoon-like blood parasites (Apicomplexa) of birds are closely related to the amphibian parasite Lankesterella minima. Little is known about the biology of these pathogens in birds, including their distribution, life cycles, specificity, vectors, and molecular characterization. Using blood samples of 641 birds from 16 species, we (i) determined the prevalence and molecular diversity of Lankesterella parasites in naturally infected birds; (ii) investigated the development of Lankesterella kabeeni in laboratory-reared mosquitoes, Culex pipiens forma molestus and Aedes aegypti; and (iii) tested experimentally the susceptibility of domestic canaries, Serinus canaria, to this parasite. This study combined molecular and morphological diagnostic methods and determined 11% prevalence of Lankesterella parasites in Acrocephalidae birds; 16 Lankesterella lineages with a certain degree of host specificity and two new species (Lankesterella vacuolata n. sp. and Lankesterella macrovacuolata n. sp.) were found and characterized. Lankesterella kabeeni (formerly Hepatozoon kabeeni) was re-described. Serinus canaria were resistant after various experimental exposures. Lankesterella sporozoites rapidly escaped from host cells in vitro. Sporozoites persisted for a long time in infected mosquitoes (up to 42 days post exposure). Our study demonstrated a high diversity of Lankesterella parasites in birds, and showed that several avian Hepatozoon-like parasites, in fact, belong to Lankesterella genus.

scholarly journals Dominant-Negative FADD Rescues the In Vivo Fitness of a Cytomegalovirus Lacking an Antiapoptotic Viral Gene

2007 ◽  
Vol 82 (5) ◽  
pp. 2056-2064 ◽  
Author(s):  
Luka Čičin-Šain ◽  
Zsolt Ruzsics ◽  
Juergen Podlech ◽  
Ivan Bubić ◽  
Carine Menard ◽  
...  
Keyword(s):  
Virus Replication ◽  
Control Cell ◽  
Death Receptor ◽  
Formal Proof ◽  
Dominant Negative ◽  
Viral Fitness ◽  
Viral Gene ◽  
Apoptosis Inhibition

ABSTRACT Genes that inhibit apoptosis have been described for many DNA viruses. Herpesviruses often contain even more than one gene to control cell death. Apoptosis inhibition by viral genes is postulated to contribute to viral fitness, although a formal proof is pending. To address this question, we studied the mouse cytomegalovirus (MCMV) protein M36, which binds to caspase-8 and blocks death receptor-induced apoptosis. The growth of MCMV recombinants lacking M36 (ΔM36) was attenuated in vitro and in vivo. In vitro, caspase inhibition by zVAD-fmk blocked apoptosis in ΔM36-infected macrophages and rescued the growth of the mutant. In vivo, ΔM36 infection foci in liver tissue contained significantly more apoptotic hepatocytes and Kupffer cells than did revertant virus foci, and apoptosis occurred during the early phase of virus replication prior to virion assembly. To further delineate the mode of M36 function, we replaced the M36 gene with a dominant-negative FADD (FADDDN) in an MCMV recombinant. FADDDN was expressed in cells infected with the recombinant and blocked the death-receptor pathway, replacing the antiapoptotic function of M36. Most importantly, FADDDN rescued ΔM36 virus replication, both in vitro and in vivo. These findings have identified the biological role of M36 and define apoptosis inhibition as a key determinant of viral fitness.

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