The main interest of the research within the group is to study mechanisms for chemically induced acute, developmental and subchronic neurotoxicity by using different neuronal cell models. The usefulness of the cell models for risk assessment is evaluated by integrating in vitro data derived from the cell models with historic in vivo data from rat and clinical observations from exposed human in predictions models. Risk assessment predictions are based on Integrated Approaches to Testing and Assessment (IATA) and Adverse Outcome Pathways (AOP). Furthermore, mechanisms for chemically induced nociception are studied in a recombinant neuronal cell model expressing the Transient Receptor Potential Vanilloid (TRPV) ion channels.

 

 

1. Neurotoxicity determined in vitro

 

The development of alternative methods for studies of neurotoxicological mechanisms has gained great success during the past years. One approach is to use cell lines of neuronal origin, which under certain culture conditions can develop into highly differentiated cells expressing specific neuronal features.   Human neuroblastoma SH-SY5Y cells can be used to study axonopathy, which can be induced by neurotoxic chemicals (e.g. acrylamide and gliotoxin) or increased glucose concentrations. The model can also be used to study toxic insult to neurons during development, as exemplified in a study of neurite outgrowth after exposure to low dose γ-irradiation or agricultural mitochondrial inhibitor pesticides. The SH-SY5Y cells are also useful for studies on acetylcholine receptor signaling and esterase activity. These endpoints, together with eg.  noradrenalin uptake, cell membrane potential and voltage operated calcium channel function have been evaluated as neuronal markers for acute neurotoxicity in the EU-financed projects ACuteTox and the EU-ToxRisk.   The neural progenitor cell line C17.2 is derived from neonatal mouse cerebellum and immortalized by v-myc transfection. The multipotent progenitor cells can differentiate into neurons and astrocytes after 8 days in culture in serum-free medium which is supplemented with neurotrophic factors. The potential of the mixed cell culture as a substitute to primary embryonic rat brain cell cultures is investigated. The neuronal and glia phenotypes are evaluated biochemically and functionally.   By using transcriptional markers that are significantly deregulated during differentiation, together with structural and functional endpoints in our two principal cell models, we aim to develop robust assays to be used for identification of chemicals that may induce developmental neurotoxicity.      

2. The NociOcular test: TRPV1-expressing cells as a model for eye-irritation

 

Draize’s eye irritation test is required as the principal test method for classification of eye irritation. The Draize test has been criticized because of its cruelty to the animals and the subjective judgment of eye toxicity. Large efforts have resulted in several alternative methods for estimation of ocular toxicity. However, none of these take sensory stimulation of nerves into consideration; a feature which should be correlated with mild irritation. We have developed a promising cell model, which may be useful for detection of mild eye irritation. SH-SY5Y cells are transfected with the Transient Receptor Potential Vanilloid, type 1 (TRPV1) ion channel. TRPV1 can be activated by nociceptive (pain-inducing) compounds, acidic pH and noxious heat. Our research has shown that anionic linear aliphatic detergents, which are known to induce severe ocular pain and eye irritation, also activate the receptor. There is also a strong correlation between the eye stinging potential of personal hygiene products and the lowest effective concentration determined in the NociOcular test.   The use of the TRPV1 expressing SH-SY5Y cells for identification of chemicals that irritate the upper respiratory air ways are now evaluated in a collaboration with Gunnar Johansson at Karolinska Institutet.  

PhD students

Ylva Johansson