Use Of Organotypic Cultures Research Articles

A Critical Need for Better Cancer Immunotherapy Models: Are Organotypic Tumor Spheroid Cultures the Answer?

<b/> Immunotherapy has transformed the therapeutic landscape of cancer, but the preclinical evaluation of combination approaches that will deepen and broaden its clinical benefit has lagged far behind due to the lack of expedient and easily accessible ex vivo human systems. In this issue, Jenkins and colleagues and Deng and colleagues report the use of organotypic cultures of tumors derived from mice and humans containing both tumor cells and cells from their local immune microenvironment to recapitulate the in vivo use of immune checkpoint inhibitors and extend the application of this system to therapeutic combinations of immune checkpoint blockade and molecularly targeted agents. Cancer Discov; 8(2); 143-5. ©2018 AACR.See related article by Jenkins et al., p. 196See related article by Deng et al., p. 216.

Cigarette Mainstream Smoke: The Evolution of Methods and Devices for Generation, Exposure and Collection

SUMMARY The objective of this review is to support tobacco scientists when evaluating information published on smoking machines, and on cigarette mainstream smoke (in vivo and in vitro) exposure systems and collection devices. The intriguing development of smoking machines (mainly for cigarettes) is followed for more than 170 years - from the first simple set-ups in the 1840s to the sophisticated and fully automated analytical smoking machines available today. Systems for the large-scale production of smoke (condensate) for preparative work are equally considered. The standardization of machine smoking methods and test pieces has solved several technical problems and produced sensible rules but, at the same time, given rise to new controversies like the compatibility of artificial and human smoking, and the implementation of more intense machine smoking regimes. Adequate space is allotted for the discussion of configurations for in vivo smoke exposure of rodent and non-rodent species and the machines generating the required smoke (condensate). Covered as well is the field of in vitro toxicity testing, including the increasingly informative new techniques of air-liquid interface exposure, which are becoming more and more refined with the use of organotypic cultures and genetic analyses. The review is completed by the examination of the considerable variety of mainstream smoke collection devices (filters and traps) developed over time - some for very specific purposes - and refers to the perpetual problem of artifact formation by aging.

Pelota Regulates Epidermal Differentiation by Modulating BMP and PI3K/AKT Signaling Pathways

The depletion of evolutionarily conserved pelota protein causes impaired differentiation of embryonic and spermatogonial stem cells. In this study, we show that temporal deletion of pelota protein before epidermal barrier acquisition leads to neonatal lethality due to perturbations in permeability barrier formation. Further analysis indicated that this phenotype is a result of failed processing of profilaggrin into filaggrin monomers, which promotes the formation of a protective epidermal layer. Molecular analyses showed that pelota protein negatively regulates the activities of bone morphogenetic protein and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathways in the epidermis. To address whether elevated activities of bone morphogenetic protein and PI3K/AKT signaling pathways were the cause for the perturbed epidermal barrier in Pelo-deficient mice, we made use of organotypic cultures of skin explants from control and mutant embryos at embryonic day 15.5. Inhibition of PI3K/AKT signaling did not significantly affect the bone morphogenetic protein activity. However, inhibition of bone morphogenetic protein signaling caused a significant attenuation of PI3K/AKT activity in mutant skin and, more interestingly, the restoration of profilaggrin processing and normal epidermal barrier function. Therefore, increased activity of the PI3K/AKT signaling pathway in Pelo-deficient skin might conflict with the dephosphorylation of profilaggrin and thereby affect its proper processing into filaggrin monomers and ultimately the epidermal differentiation.

Organotypic Cultures as a Model to Study Adult Neurogenesis in CNS Disorders.

Neural regeneration resides in certain specific regions of adult CNS. Adult neurogenesis occurs throughout life, especially from the subgranular zone of hippocampus and the subventricular zone, and can be modulated in physiological and pathological conditions. Numerous techniques and animal models have been developed to demonstrate and observe neural regeneration but, in order to study the molecular and cellular mechanisms and to characterize multiple types of cell populations involved in the activation of neurogenesis and gliogenesis, investigators have to turn to in vitro models. Organotypic cultures best recapitulate the 3D organization of the CNS and can be explored taking advantage of many techniques. Here, we review the use of organotypic cultures as a reliable and well defined method to study the mechanisms of neurogenesis under normal and pathological conditions. As an example, we will focus on the possibilities these cultures offer to study the pathophysiology of diseases like Alzheimer disease, Parkinson's disease, and cerebral ischemia.

Temporal and spatial regulation of interneuron distribution in the developing cerebral cortex—an in vitro study

GABAergic interneurons are local circuit cells that control the excitatory balance in most regions of the nervous system, particularly the cerebral cortex. Because they are integrated in every cortical module, we posed the question whether interneuronal precursors would display some topographic specificity between their origin at the ventral telencephalon and their cortical location after migration. If this was true, GABAergic cells would have to be provided with intrinsic features that would make them able to perform specific functional roles in each specific module. On the other hand, if no topography was found, one would conclude that inhibitory precursors would be functionally naive, being able to integrate anywhere in the cortex, with equal capacity of performing their functions. This issue was approached by use of organotypic cultures of wild mice embryonic slices, into which fragments of the ganglionic eminence taken from enhanced green fluorescent protein (eGFP) mice were implanted, observing the topographic location of both the implant and its destination. Despite the existence of different genetic domains in the ventricular zone of the medial ganglionic eminences (MGE), we found that cells originating in different regions spread in vitro all over the mediolateral axis of the developing cortical wall, independently of their sites of origin. Results favor the hypothesis that GABAergic precursors are functionally naive, integrating into modules irrespective of which cortical area they belong to.

Organotypic Cultures as Tools for Testing Neuroactive Drugs – Link Between In-Vitro and In-Vivo Experiments

The development of neuroactive drugs is a time consuming procedure. Candidate drugs must be run through a battery of tests, including receptor studies and behavioural tests on animals. As a rule, numerous substances with promising properties as assessed in receptor studies must be eliminated from the development pipeline in advanced test phases because of unforeseen problems like intolerable side-effects or unsatisfactory performance in the whole organism. Clearly, test systems of intermediate complexity would alleviate this inefficiency. In this review, we propose cultured organotypic brain slices as model systems that could bridge the 'interpolation gap' between receptors and the brain, with a focus on the development of new general anaesthetics with lesser side effects. General anaesthesia is based on the modulation of neurotransmitter receptors and other conductances located on neurons in diverse brain regions, including cerebral cortex and spinal cord. It is well known that different components of general anaesthesia, e.g. hypnosis and immobility, are produced by the depression of neuronal activity in distinct brain regions. The ventral horn of the spinal cord is an important structure for the induction of immobility. Thus, the potentially immobilizing effects of a newly designed drug can be estimated from its depressant effect on neuronal network activity in cultured spinal slices. A drug's sedative and hypnotic potential can be examined in cortical cultures. Combined with genetically engineered mice, this approach can point to receptor subtypes most relevant to the drug's intended net effect and in return can help in the design of more selective drugs. In conclusion, the use of organotypic cultures permits predictions of neuroactive properties of newly designed drugs on an intermediate level, and should therefore open up avenues for a more creative and economic drug development process.

Organotypic Cultures as Tool to Test Long-Term Effects of Chemicals on the Nervous System

The study of neuroscience has vastly benefited from the use of brain slices. This preparation has been fundamental for the understanding of the cellular basis of nervous system function as well as for the study of the mechanisms involved in neuronal network dysfunction. This experimental model provides flexible access, and control of, specific neural circuits and maintains their basic properties, allowing them to reproduce most of their natural network activities. Brain slices permit the combination of sophisticated techniques such as electrophysiology, fluorescence imaging, pharmacology, molecular biology, etc. More recently, the development of organotypic brain slice cultures has expanded the use of modern technical approaches to the study neuronal networks, while increasing their possibilities of evaluating long-term effects of acute experimental conditions, as well as the effects of chronic treatments on neuronal network function in vitro. Here, I will provide an overview of the use of organotypic cultures to understand neuronal network function and dysfunction, as well as the pharmacological approaches used for these studies. As a final example, I will review the studies performed in organotypic cultures regarding the deleterious effects of long-term amyloid beta application on neuronal networks in vitro, as well as the use of drugs that may prevent or revert their deleterious effects on nervous system function. Overall, this review will provide elements to support the use of organotypic cultures as a very reliable model to explore long-term neuropharmacological studies in vitro.

Comparative investigations to evaluate the use of organotypic cultures of transformed and native dermal and epidermal cells for permeation studies

In a comparative study organotypic cultures of both transformed and native dermal and epidermal cells were used for permeation studies. In these organotypic cultures the dermal cells are incorporated into a contracted collagen gel, the epidermal cells are seeded on top of this gel and form a multilayered stratified epidermis when cultivated at the air–liquid interface. For permeation studies two different donor systems containing ibuprofen acid were used, Ibutop-Creme ® and Dolgit-Mikrogel ®. Studies using excised human stratum corneum showed differences in drug permeability for these two formulations which were also observed when the native organotypic cultures were used. In general, organotypic cultures show a higher permeability for topically applied drugs than excised human stratum corneum, the cultures consisting of transformed cells showed an increase in drug permeability for the Dolgit-Mikrogel ® compared with the native cultures which might be due to a higher sensitivity for the enhancer isopropanol in this formulation.

Synaptogenesis in mouse cerebellum: A comparative in vivo and tissue culture study

The synaptic development of organotypic cultures of cerebellum derived from new-born mice was examined by light and electron microscopy at 5, 8, 12 and 19 days in vitro. These explants were then compared with cerebellar tissue from mice killed by perfusion at corresponding ages. The comparison suggests that there is an initial lag in synaptic development most clearly seen at 5 and 8 days in vitro, followed by an accelerated development resulting in close in vivo and in vitro correspondence by day 19. The findings suggest that synaptic development of cerebellum in vitro follows in vivo development with fidelity despite substantial disruption of cell migration patterns, and further validates the use of organotypic cultures for physiological, biochemical, and pharmacological study.