scholarly journals Effects of fasciculation on the outgrowth of neurites from spinal ganglia in culture.

1980 ◽  
Vol 87 (2) ◽  
pp. 370-378 ◽  
Author(s):  
U Rutishauser ◽  
G M Edelman
Keyword(s):  
Neurite Outgrowth ◽  
Cell Adhesion Molecule ◽  
Capillary Tube ◽  
Single Cells ◽  
Spinal Ganglia ◽  
Cell Aggregates ◽  
Preferential Growth ◽  
Nerve Growth ◽  
High Concentrations

This report describes the influence of neurite fasciculation on two aspects of nerve growth from chick spinal ganglia in vitro: the inhibition of outgrowth by high concentrations of nerve growth factor (NGF) and the preferential growth of neurites toward a capillary tube containing NGF. These studies involved a comparison of cultures of single cells, cell aggregates, and intact ganglia and the use of antibodies against the nerve cell adhesion molecule (CAM) to perturb fasciculation under a variety of conditions. The inhibition of outgrowth, which was observed with ganglia and aggregates but not with single cells, was correlated with a thickening of neurite fascicles. In accord with this observation, anti-CAM, which diminishes fasciculation by inhibiting side-to-side interactions between individual neurites, also partially reversed the inhibition of neurite outgrowth at high NGF concentrations. On the basis of these and other studies, we consider the possibility that neurite bundling causes an increase in the elastic tension of a fascicle without a compensatory increase in its adhesion to substratum. It is proposed that this imbalance could inhibit neurites from growing out from a ganglion and even result in retraction of preexisting outgrowth. In the analysis of NGF-directed growth, it was found that a capillary source of NGF produced a steep but transient NGF gradient that subsided before most neurites had emerged from the ganglion. Nevertheless, the presence of a single NGF capillary caused a dramatic and persistent asymmetry in the outgrowth of neurites from ganglia or cell aggregates. In contrast, processes of individual cells did not appear to orient themselves toward the capillary. The most revealing finding was that anti-CAM antibodies caused a decrease in the asymmetry of neurite outgrowth. These results suggest that side-to-side interactions among neurites can influence the guidance of nerve bundles by sustaining and amplifying an initial directional signal.

The in vitro effect of the nerve growth factor on chick embryo spinal ganglia—a light-microscopic evaluation

Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 381-392
Author(s):  
Peddrick Weis
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Chick Embryo ◽  
Culture Period ◽  
Spinal Ganglia ◽  
Nerve Growth ◽  
Microscopic Evaluation ◽  
Vitro Effect

The effect of the nerve growth factor (NGF) on chick embryo spinal ganglia was studied in the hanging-drop bioassay system by comparison with parallel development in vivo. The well-differentiated ventrolateral neuroblasts, which in vivo increase 1·33 times in size during the culture period, did not increase in size at all in vitro. Only 65–72% survived to the end of the culture period regardless of the NGF concentration. The less-differentiated mediodorsal (M-D) neuroblasts, which in vivo increase 1·31 times in size during the culture period, were found to increase equally in vitro if sufficient NGF was present. Such a quantity was greater than that which evoked maximum outgrowth of neurites. Survival of M-D neuroblasts was also related to NGF concentration but did not equal the in vivo condition even at the highest concentration. The hyperchromatic type of degeneration prevented by high NGF concentrations is that which results in vivo from insufficient peripheral field. From this and other reports it would appear that the response to NGF seen in vitro is due only to the M-D neuroblasts, and that all biochemical and cytological observations which have been reported would therefore represent conditions within those cells only.

Rapid and Irreversible Alteration of the Ability of Hematopoietic Stem Cells To Execute Both Symmetric and Asymmetric Self-Renewal Divisions by Exposure to Reduced Steel Factor Concentrations with No Effect on Their Survival or Mitogenesis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 684-684
Author(s):  
David G. Kent ◽  
Brad Dykstra ◽  
Connie J. Eaves
Keyword(s):  
Bone Marrow ◽  
Adult Mouse ◽  
Single Cells ◽  
Mouse Bone Marrow ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Steel Factor ◽  
High Concentrations

Abstract Hematopoietic stem cells (HSCs) are present in the marrow of adult mice at a frequency of 1/104, as measured by limiting dilution transplantation assays for individual cells that produce lymphoid (B and T) as well as myeloid (GM) cells for at least 4 months in irradiated recipients. HSCs thus defined can be reproducibly isolated in the CD45midlin−Rho−SP fraction of adult mouse bone marrow at a purity of >30%. In mice, mutations in c-kit, the receptor for Steel factor (SF) lead to substantial reductions in the adult HSC population. In vitro, SF has been identified as a potent regulator of HSC self-renewal divisions. High concentrations of SF in combination with IL-11 allow adult HSCs to divide with a net 2–4 fold expansion in HSC numbers after 10 days and low concentrations of SF result in loss of HSC activity. To investigate the cellular mechanisms underlying these different outcomes, we cultured 114 CD45midlin−Rho−SP adult mouse bone marrow cells in single cell cultures containing serum-free medium + 20 ng/ml IL-11 and either 300 or 10 ng/ml of SF. Each culture was then examined every 4–6 hr. The kinetics of division of these cells under both conditions was identical with completion of the 1st division occurring between 22–68 hr. During that time none of the input cells died (<1%). After 10 days of culture, during which time all input cells divided at least 5 times (>50 cells), the HSC content of pooled clones (as measured by in vivo transplantation assays) was found to be >10-fold higher in the clones generated under high vs. low SF conditions (p<0.05). To characterize the types of self-renewal divisions undertaken, 9 doublets generated under the high SF condition were harvested between 4 and 8 hr after they underwent their 1st division and then each of the daughters was injected into a separate irradiated mouse. Analysis of the 18 mice showed that for one of the input cells both daughters were HSCs (evidence of a symmetric self-renewal division) and for 3 more, only one of the 2 daughters was an HSC (evidence of an asymmetric self-renewal division). In contrast no daughter HSCs were identified when 6 doublets produced under the low SF condition were assayed. To determine whether the loss of HSC activity under low SF conditions was a pre- or post-mitotic event, additional in vivo HSC assays were performed on cells harvested from individual wells after 8, 16 and 96 hours of incubation. The results revealed no change in the proportion of wells with either low or high concentrations of SF that contained HSCs after 8 hr of incubation (10/36 positive mice injected with starting single cells and 5/17 (low SF) vs. 6/17 (high SF) positive mice injected with 8-hr single cells, respectively). However, a significant difference (p<0.01) was seen after 96 hr (5/35 vs. 2/43 positive mice, respectively) and, after only 16 hr, before a first mitosis was seen under either condition, a decline in HSCs was apparent under the low SF condition (4/15 vs. 1/15 positive mice injected with cells from the high vs. low SF condition). Together, these studies indicate that HSC exposure to different SF concentrations can rapidly and irreversibly alter the ability of HSCs to execute symmetric as well asymmetric self-renewal divisions in vitro.

scholarly journals Endostatin binds nerve growth factor and thereby inhibits neurite outgrowth and neuronal migration in-vitro

2010 ◽  
Vol 1360 ◽  
pp. 28-39 ◽  
Author(s):  
Abraham Al Ahmad ◽  
Boyeon Lee ◽  
Jonathan Stack ◽  
Christi Parham ◽  
Joel Campbell ◽  
...  
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Neuronal Migration ◽  
Nerve Growth

scholarly journals Nerve growth factor-induced neurite outgrowth in PC12 cells involves the coordinate induction of microtubule assembly and assembly-promoting factors.

1985 ◽  
Vol 101 (5) ◽  
pp. 1799-1807 ◽  
Author(s):  
D G Drubin ◽  
S C Feinstein ◽  
E M Shooter ◽  
M W Kirschner
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Time Course ◽  
Microtubule Assembly ◽  
Nerve Growth ◽  
Peripheral Neurons ◽  
Associated Proteins

Nerve growth factor (NGF) regulates the microtubule-dependent extension and maintenance of axons by some peripheral neurons. We show here that one effect of NGF is to promote microtubule assembly during neurite outgrowth in PC12 cells. Though NGF causes an increase in total tubulin levels, the formation of neurites and the assembly of microtubules follow a time course completely distinct from that of the tubulin induction. The increases in microtubule mass and neurite extension closely parallel 10- and 20-fold inductions of tau and MAP1, proteins shown previously to promote microtubule assembly in vitro. When NGF is removed from PC12 cells, neurites disappear, microtubule mass decreases, and both microtubule-associated proteins return to undifferentiated levels. These data suggest that the induction of tau and MAP1 in response to NGF promotes microtubule assembly and that these factors are therefore key regulators of neurite outgrowth.

scholarly journals A human organoid system that self-organizes to recapitulate growth and differentiation of a benign mammary tumor

2019 ◽  
Vol 116 (23) ◽  
pp. 11444-11453 ◽  
Author(s):  
Stefan Florian ◽  
Yoshiko Iwamoto ◽  
Margaret Coughlin ◽  
Ralph Weissleder ◽  
Timothy J. Mitchison
Keyword(s):  
Cell Biology ◽  
Single Cells ◽  
3D Culture ◽  
Cell Types ◽  
Cell Polarization ◽  
Cell Aggregates ◽  
Usual Ductal Hyperplasia ◽  
Sequence Of Events ◽  
Ductal Hyperplasia

As 3D culture has become central to investigation of tissue biology, mammary epithelial organoids have emerged as powerful tools for investigation of epithelial cell polarization and carcinogenesis. However, most current protocols start from single cells suspended in Matrigel, which can also restrict cell differentiation and behavior. Here, we show that the noncancerous mammary cell line HMT-3522 S1, when allowed to spontaneously form cell aggregates (“spheroids”) in medium without Matrigel, switches to a collective growth mode that recapitulates many attributes of “usual ductal hyperplasia” (UDH), a common benign mammary lesion. Interestingly, these spheroids undergo a complex maturation process reminiscent of embryonic development: solid-cell cords form their own basement membrane, grow on the surface of initially homogeneous cell aggregates, and form asymmetric lumina lined by two distinct cell types that express basal and luminal cytokeratins. This sequence of events provides a cellular mechanism that explains how the characteristic crescent-shaped, asymmetrical lumina form in UDH. Our results suggest that HMT-3522 S1 spheroids are useful as an in vitro model system to study UDH biology, glandular lumen formation, and stem cell biology of the mammary gland.

Entrapment of Cultured Pancreas Islets in Three-Dimensional Collagen Matrices

1992 ◽  
Vol 1 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Seh-Huang Chao ◽  
Madhusudan V. Peshwa ◽  
David E.R. Sutherland ◽  
Wei-Shou Hu
Keyword(s):  
Beta Cell ◽  
In Vitro Culture ◽  
Islets Of Langerhans ◽  
Single Cells ◽  
Three Dimensional ◽  
Dependent Manner ◽  
Cell Aggregates ◽  
Collagen Gels ◽  
Ideal System

In vitro culture of islets of Langerhans decreases their immunogenecity, presumably by eliminating passenger leukocytes and other Ia+ presenting cells within the islets. Islets cultivated in petri dishes either at 37°C or at 25°C gradually disintegrate during culture in a time-dependent manner which is related to the free-floating condition of the islets. Also, a fraction of the islets disperse as single cells and beta-cell aggregates or adhere to the bottom of the culture dishes. Thus, the retrieval rate of transplantable islets is dampened due to their disintegration and spontaneous dispersion in conventional petri dish cultures. Entrapment of freshly harvested islets of Langerhans in a three-dimensional collagen matrix was studied as an alternative method for islet cultivation. The contraction of collagen fibrils during in vitro culture counteracts the dispersion of islets and helps in maintaining their integrity while in culture. It was observed that the entrapped islets maintain satisfactory morphology, viability, and capability of glucose-dependent insulin secretion for over 2 wk. The oxygen consumption rate and glucose metabolism of these islets was not deranged when entrapped in collagen. Also, the retrieval of islets is easier and more efficient than that observed in conventional culture systems. Our results indicate that culture of islets in three-dimensional collagen gels can potentially develop into an ideal system applicable to clinical transplantation of cultured islets or beta-cell aggregates.

scholarly journals Chlorhexidine inhibits L1 cell adhesion molecule–mediated neurite outgrowth in vitro

2013 ◽  
Vol 75 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Aaron M. Milstone ◽  
Penny Bamford ◽  
Susan W. Aucott ◽  
Ningfeng Tang ◽  
Kimberly R. White ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Neurite Outgrowth ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
L1 Cell Adhesion Molecule

scholarly journals Stiff-to-Soft Transition from Glass to 3D Hydrogel Substrates in Neuronal Cell Culture

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 165
Author(s):  
Gulden Akcay ◽  
Regina Luttge
Keyword(s):  
Single Cells ◽  
Neuroblastoma Cells ◽  
Neuronal Cell ◽  
Seeding Density ◽  
Cell Aggregates ◽  
Cell Seeding ◽  
Glycol Diacrylate ◽  
Cell Seeding Density ◽  
Wide Range

Over the past decade, hydrogels have shown great potential for mimicking three- dimensional (3D) brain architectures in vitro due to their biocompatibility, biodegradability, and wide range of tunable mechanical properties. To better comprehend in vitro human brain models and the mechanotransduction processes, we generated a 3D hydrogel model by casting photo-polymerized gelatin methacryloyl (GelMA) in comparison to poly (ethylene glycol) diacrylate (PEGDA) atop of SH-SY5Y neuroblastoma cells seeded with 150,000 cells/cm2 according to our previous experience in a microliter-sized polydimethylsiloxane (PDMS) ring serving for confinement. 3D SH-SY5Y neuroblastoma cells in GelMA demonstrated an elongated, branched, and spreading morphology resembling neurons, while the cell survival in cast PEGDA was not supported. Confocal z-stack microscopy confirmed our hypothesis that stiff-to-soft material transitions promoted neuronal migration into the third dimension. Unfortunately, large cell aggregates were also observed. A subsequent cell seeding density study revealed a seeding cell density above 10,000 cells/cm2 started the formation of cell aggregates, and below 1500 cells/cm2 cells still appeared as single cells on day 6. These results allowed us to conclude that the optimum cell seeding density might be between 1500 and 5000 cells/cm2. This type of hydrogel construct is suitable to design a more advanced layered mechanotransduction model toward 3D microfluidic brain-on-a-chip applications.

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