Impedance & other original tools for cellular models

In the fields of biology and human and veterinary medicine, much progress has been made over the past 20 years. The new areas of investigation are often linked to technological progress and if big data has not revealed all its secrets, or if 3D bioprinters have not proposed new study models in all expected domains, many innovative technologies have enter in the laboratories of the 21st century. Thus, the cellular culture often presented as a long and tedious technique knows a small revolution with the arrival of real-time technologies. After the Real Time PCR techniques in molecular biology, Real Time Cell Analysis (RTCA) in cell biology opens up new perspectives in many applications. An original platform name Impedancell, labeled in 2019 by the French IBISA (French certification body for technologies applied to research in the living world) was built in Normandy to manage this new paradigm. ImpedanCELL is an innovative and original core facility for studying real-time high-throughput cellular activity using impedance measurement (xCELLigence technology) and real-time cellular imaging. It is localised on two different geographical sites in Caen (Normandy, France): Comprehensive Cancer Center F. Baclesse for all non-microbiology applications and LABEO (Equine Normandy Equine Valley Biotechnology platform and BIOTARGEN research team) for all applications in virology and in bacteriology (biosafety level 2). The core facility is equipped with cutting-edge technologies (3 xCELLigence MP, 1 xCELLigence DP, 1 iCELLigence, 1 Cellavista, 2 Incucytes…) allowing the study of adhesion, proliferation, cell death, migration and invasion in various domains including oncology, neurosciences, toxicology, immunology, marine biology, virology and bacteriology. In line with one ImpedanCELL’s mission, the core facility is open to any scientists with high-throughput study needs for dynamic tracking of real-time cellular behaviour. ImpedanCELL is open to collaborations and services for both academic and industrial partners and offers theoretical and practical courses. Two different applications performed on each site are presented with the advantage of this new technology for two areas of expertise in each laboratory: equine virology on the one hand and human cancer research on the other. Among the infectious agents found in the equine species, herpesviruses are certainly among those causing the greatest economic losses in the world. Equid alpha-herpesviruses (EHV) are responsible for different diseases in equine population. EHV-1 causes respiratory diseases, abortions and nervous disorders, EHV-4 causes respiratory diseases and sporadic abortion while EHV-3 is responsible of equine coital exanthema. In view of the lack of efficacy of vaccines against EHV-1 and EHV-4 and in the absence of vaccines against EHV-3, the use of antiviral treatment is of great interest. Our team recently documented the interest of the Real-Time Cell Analysis technology to monitor the cytopathic effects (CPE) induced by these viruses on equine dermal cells, and established the efficacy of this method to evaluate the antiviral effect of aciclovir (ACV) and ganciclovir (GCV). In addition, RTCA technology has also been found suitable for high throughput screening of small molecules against EHV , allowing identification of several molecules of interest as a new antiviral against EHV, among them spironolactone is a potential candidate.1 In the field of oncology, repositioning is also an interesting approach and, in this respect, the RTCA are technologies of interest. The development of direct Mcl-1 inhibiting molecules constitutes a major challenge for the success of Bcl-xL targeting strategies in ovarian carcinoma. After computational modelling to identify molecules able to target the Mcl 1 hydrophobic pocket, a high throughput functional screening assay based on xCELLigence technology was implemented to evaluate the ability of designed and synthesized molecules called oligopyridines to sensitize ovarian carcinoma cells (in addiction to both Bcl-xL and Mcl-1) to Bcl xL-targeting strategies. After establishing structure-activity relationships and identifying a potent lead (hit) called Pyridoclax, surface plasmon resonance assay demonstrated that pyridoclax directly binds to Mcl-1. Without cytotoxic activity when administered as a single agent, pyridoclax induced apoptosis in combination with Bcl-xL targeting siRNA or with ABT 737 in ovarian cancer cells. These results open up interesting perspectives for the clinical use of Mcl-1 inhibitors to improve the clinical management of ovarian cancer.2 Overall, these two high-throughput studies demonstrated the interest to use impedance based technologies to identify some pertinent targets and molecules for therapeutic intervention in the context of the precision medicine in ovarian cancer an in EHV infectious disease in horses. Our study confirms the efficiency of RTCA to monitor CPE formation induced by EHV-1 on E. Derm cells, and further extends this tool to EHV-4 and EHV-3. In the infectious field, applications in bacteriology and in particular studies on biofilms also use this technology which facilitates the screening of antibiotics. The use in the field of immunology is also booming. While the interest of screening by impedance measurements is well established, real-time monitoring of cell development under the microscope remains essential. Engineers have understood this, which explains the arrival in 2020 of one technology coupling these two approaches.