Targeting of ADAMTS5's ancillary domain with the recombinant mAb CRB0017 ameliorates disease progression in a spontaneous murine model of osteoarthritis.

OBJECTIVE: ADAMTS5 (aggrecanase-2) has been demonstrated to be crucial in the development of osteoarthritis (OA), by use of several mouse mutants carrying either truncated, catalytically inactive enzymes or aggrecanase-resistant mutant aggrecan. We have selected recombinant monoclonal antibodies directed against ADAMTS5, by using Intracellular Antibody Capture Technology (IACT). CRB0017 revealed very high affinity for the enzyme in Biacore analyses and very good specificity in a panel of binding assays. Therefore, we tested CRB0017 in a relevant spontaneous OA model, the STR/ort mouse. DESIGN: STR/ort male mice were recruited at 5 months of age, and treated intra-articularly in each knee with CRB0017 1.2 µg, CRB0017 12 µg, or vehicle. After 6 weeks, the intra-articular administration of CRB0017 was repeated with the same doses. After 3 months from recruitment, the animals were sacrificed and the femorotibial joints processed for histology and scored in a blind fashion according to both Mankin's and the OARSI methods. RESULTS AND CONCLUSIONS: All histological scores were significantly decreased in the CRB0017 12 µg/knee group compared to vehicle, while administration of CRB0017 1.2 µg was associated with a trend to a decrease in the same parameters. Therefore, CRB0017 administered twice in 3 months could modify the course of OA in the STR/ort mouse, by delaying cartilage breakdown as assessed histologically. The procedure of blind scoring of the histological samples clearly showed that knee intra-articular administration of CRB0017, an anti-ADAMTS5 antibody, dose-dependently improved disease progression in a relevant animal model of OA.

Aggresome-forming TTRAP mediates pro-apoptotic properties of Parkinson's disease-associated DJ-1 missense mutations.

Mutations in PARK7 DJ-1 have been associated with autosomal-recessive early-onset Parkinson's disease (PD). This gene encodes for an atypical peroxiredoxin-like peroxidase that may act as a regulator of transcription and a redox-dependent chaperone. Although large gene deletions have been associated with a loss-of-function phenotype, the pathogenic mechanism of several missense mutations is less clear. By performing a yeast two-hybrid screening from a human fetal brain library, we identified TRAF and TNF receptor-associated protein (TTRAP), an ubiquitin-binding domain-containing protein, as a novel DJ-1 interactor, which was able to bind the PD-associated mutations M26I and L166P more strongly than wild type. TTRAP protected neuroblastoma cells from apoptosis induced by proteasome impairment. In these conditions, endogenous TTRAP relocalized to a detergent-insoluble fraction and formed cytoplasmic aggresome-like structures. Interestingly, both DJ-1 mutants blocked the TTRAP protective activity unmasking a c-jun N-terminal kinase (JNK)- and p38-MAPK (mitogen-activated protein kinase)-mediated apoptosis. These results suggest an active role of DJ-1 missense mutants in the control of cell death and position TTRAP as a new player in the arena of neurodegeneration.

Strategies for identifying genes that play a role in spinal cord regeneration.

A search for genes that promote or block CNS regeneration requires numerous approaches; for example, tests can be made on individual candidate molecules. Here, however, we describe methods for comprehensive identification of genes up- and down-regulated in neurons that can and cannot regenerate after injury. One problem concerns identification of low-abundance genes out of the 30,000 or so genes expressed by neurons. Another difficulty is knowing whether a single gene or multiple genes are necessary. When microchips and subtractive differential display are used to identify genes turned on or off, the numbers are still too great to test which molecules are actually important for regeneration. Candidates are genes coding for trophic, inhibitory, receptor and extracellular matrix molecules, as well as unknown genes. A preparation useful for narrowing the search is the neonatal opossum. The spinal cord and optic nerve can regenerate after injury at 9 days but cannot at 12 days after birth. This narrow window allows genes responsible for the turning off of regeneration to be identified. As a next step, sites at which they are expressed (forebrain, midbrain, spinal cord, neurons or glia, intracellular or extracellular) must be determined. An essential step is to characterize proteins, their levels of expression, and their importance for regeneration. Comprehensive searches for molecular mechanisms represent a lengthy series of experiments that could help in devising strategies for repairing injured spinal cord.