VHHs as disease modifying therapeutics for osteoarthritis
Lisanne Morshuis is a PhD student in the department Developmental BioEngineering. (Co)Promotors are prof.dr. H.B.J. Karperien; dr. B. Zoetbier and dr. J. Hendriks from the faculty Science & Technology.
Osteoarthritis (OA) is the most prevalent chronic joint disease among the worldwide population, causing (severe) pain and even disability. The complexity of the disease makes it challenging to treat and, despite the high prevalence numbers, a disease modifying therapy has not reached the clinic yet. In OA a lot of different factors are involved in progression of the disease, such as pro-inflammatory cytokines, like IL-1β and TNFα, matrix-degrading enzymes, like MMPs, pain-inducing factors, like NGF and a lack of anabolic growth factors, like BMP7. Current therapeutic strategies based on monoclonal antibodies targeting these factors have resulted in successful pre-clinical results, but failed in clinical trials due to limited efficacy and unexpected side effects.
In this thesis we explore the use of the variable heavy domain of heavy chain only antibodies (VHH), found in the Camelidae family, as therapeutics for OA. These small antibody fragments provide many advantages over monoclonal antibodies, such as their small size (15 kDa), high affinity and stability, relatively cheap production methods and versatility for post-processing steps due to genetic engineering possibilities. Local delivery of these small VHHs could further improve the therapeutic efficacy, so we formulated the VHH in in situ-gelating hydrogels which can be injected intra-articularly for local administration and sustained release of our therapeutic.
Because of the many different factors involved in OA disease progression, this work has developed and evaluated VHHs for several therapeutic targets. A BMP7-targeting VHH was developed for sequestering the growth factor inside an injectable hydrogel for stimulating cartilage regeneration. This BMP7-sequestering VHH-hydrogel showed prolonged stimulation of BMP signalling in vitro. Furthermore, for mediating the degradation of cartilage matrix, we developed a highly specific MMP9-inhibiting VHH that was able to block the activity of this enzyme, thereby preventing collagen break-down. The sustained release of a VHH via tunable injectable hydrogels was shown using a TNFα-neutralizing VHH formulated in hyaluronic acid hydrogels for disease-triggered delivery. An NGF-neutralizing VHH was also developed within this work and showed to be effective both in vitro and in vivo in a rat MIA model for mediating pain in OA. Formulation of the VHH in the injectable hydrogels showed a sustained release profile of at least five weeks and promising therapeutic efficacy. Lastly, this work focused on developing a cartilage-targeting VHH for early diagnosis of OA with the use of next generation sequencing.
This work covers a wide range of therapeutic strategies focused on using VHHs for OA disease modification. Each of the strategies is targeting a different factor involved in OA and the therapeutic effect of the VHHs ranges from sequestering to inhibition and imaging. With this multitude of promising VHH-based approaches and injectable hydrogel-based delivery methods we made a huge step forward to disease modifying therapeutics for OA.
