For the last 15 years the Kremer labs have had a broad interest in adenovirus biology. We also use adenoviruses to address fundamental and applied biological questions. Adenoviruses are nonenveloped, double-stranded DNA pathogens with a genome size of 28 – 42 kb harbouring between 22 and 40 ORFs. To date, more than 60 human and more 150 nonhuman types described. Human adenovirus type 5 (HAd5), the prototype for vectors, is often used for vaccination and long-term gene transfer. We focus on human and canine adenoviruses (CAV-2) vectors.
OUR PRINCIPLE AREAS OF INTEREST ARE:
1) Understanding the function of CAR, the coxsackievirus adenovirus receptor, in the healthy and disease brain and during adenovirus trafficking.
As the name suggests, CAR was originally identified as an attachment molecule for coxsackie B viruses and some adenoviruses, including canine adenovirus type 2 (CAV-2) vectors, whose transduction efficacy is CAR dependent. CAR is a single-pass transmembrane protein belonging to the CTX subfamily of the Ig-super family. Its extracellular region contains two Ig-like domains and a cytoplasmic tail that includes a PDZ-domain and a clathrin adaptor protein motif. CAR function is best characterized in epithelial cells where it participates to the maintenance of tight junctions. Although a role for CAR in brain development has been hypothesized and a function in regulating axonal growth reported, its role in the adult brain is largely uncharacterized.
In this context, understanding CAR’s biological function, as well as the impact of its loss of function and distribution in the CNS is indispensable for both fundamental and applied neurobiology studies.
2) Understanding how mononuclear phagocytes, in particular dendritic cells, process and respond to immune complexed adenoviruses (IC-Ad)
The nearly ubiquitous presence of anti-Ad antibodies and memory T cells is due to recurrent and crossreacting infections during childhood. Thus, when Ad-based vectors are used in a host with memory immunity this creates an environment close to a secondary infection in the clinic.
How do IC-Ads and other host factors impact the maturation of antigen-presenting cells (APC)? Our underlying questions encompass the entry and signalling pathways and how the IC-Ads traffic in APC. In these studies we use dendritic cells (DC) to study the interaction of IC-HAd5 and innate immune sensors. DCs are the major APC in blood and tissue and play a pivotal role in the sensing of infection and activation and re-activation of the adaptive immune response.
IC-HAd5 triggers several innate immune sensors and induce DC maturation whereas the virus alone is far less potent. Our aim is thereby to understand the interactions of the IC-HAd5 during the initial activation of DC. These studies will contribute to both fundamental and applied questions in adenovirus biology, vaccination and gene therapy.
3) Understanding and treating the neurodegeneration associated with mucopolysaccharidosis type 7 (MPS VII).
Lysosomes are components of a highly orchestrated machinery involved in endocytosis, exocytosis, degradation and recycling pathways and autophagy. A dysfunction in the greater lysosome system impacts cells, organs, and organisms, and give rise to various types of lysosomal storage diseases (LSDs).
LSDs result from deficiencies in lysosomal enzymes, soluble nonenzymatic proteins, and membrane-associated proteins, followed by the subsequent accumulation of selected substrates. LSDs are multisystemic disorders with differences among the types, and the onset of symptoms depends on patients and mutations. There are 11 types of mucopolysaccharidoses (MPS), defined by the identity of the lysosomal enzyme impaired. We focus on deficiency in the β-glucuronidase, which leads to an accumulation of heparan sulfate, chondroitin sulfate and dermatan sulfate. This accumulation is at the origin of symptoms in various organs. In the CNS, the β-glucuronidase deficiency can lead to mental retardation, seizures, visual impairment and hearing loss. The cellular processes disturbed are still unknown. The existence of MPS VII mice and dog allow us to predict what may be occurring in the human CNS. Using human MPS VII induced pluripotent stem cells (iPSC) we are investigating the cellular processes that are responsible for neuronal dysfunction.
4) Optimizing CAV-2 vector for gene transfer to the CNS.
The Kremer labs created replication-defective and helper-dependent CAV-2 vectors. CAV-2 vectors allow preferential gene transfer to neurons and widespread distribution after intraparenchymal injections, We and others have used them to explore, treat and understand the healthy and diseased CNS.
To respond to the increasing number of requests for CAV-2 vectors, the CNRS BioCampus created a non-profit vector core that provides vectors at cost to colleagues.
Vasiliki Kalatzis Australian 2001-2010 Olivier Billet French 2001-2004 Harald Wodrich German 2004-2008 Hanna Dreja Swedish 2007-2008 Anne Keriel French 2004-2006 Dominique Mercier French 2006-2007 Khalil Mazouni French 2008 Matthieu Perreau French 2002-2006 Nicolas Serratrice French 2005-2009 Claire Hippert French 2005-2009 Nadia Skander Algerian 2001-2004 Carolin Buhtz/Seuring German 2005 Gregory Conductier French 2002 Lucile Pantel (...)