Optimized alkylated cyclodextrin polysulphates with reduced risks on thromboembolic accidents improve osteoarthritic chondrocyte metabolism

Objectives. To compare the ability of different cyclodextrin polysulphate (CDPS) derivatives to affect human articular cartilage cell metabolism in vitro

Cyclodextrin polysulphate protects articular cartilage in experimental lapine knee osteoarthritis

SummaryObjectiveTo evaluate the in vivo chondroprotective effect of cyclodextrin polysulphate (CDPS) in a rabbit model of experimental osteoarthritis (OA).DesignExperimental OA was induced in rabbits by anterior cruciate ligament transection (ACLT). Forty-eight hours post-surgery, the rabbits were randomised into three treatment groups (n=15 in each group) and a sham-operated control group. The rabbits were either injected subcutaneously with saline, 0.25mg/kg CDPS or 1mg/kg CDPS once a week for a period of 12 weeks, and their weight was monitored as a parameter for their general status. The animals were then sacrificed for macroscopic and histological assessment of the knee joints.ResultsAt the lowest dose, CDPS treatment was unable to induce a significant improvement of cartilage degradation vs the saline control in the experimentally induced knee OA. However, subcutaneous injections of 1mg/kg CDPS induced a marked inhibition (P<0.05) of osteophyte formation. Additionally, a significant reduction of cartilage degradation revealed an overall chondroprotective effect of CDPS at a concentration of 1mg/kg. No significant effects on weight gain were noted.ConclusionsSystemic administration of CDPS is able to protect cartilage in vivo and can therefore be considered as a chondroprotective agent with structure modifying capacities

Characterization of a novel enzyme—Starmerella bombicola lactone esterase (SBLE)—responsible for sophorolipid lactonization

We recently discovered a novel enzyme in the exoproteome of Starmerella bombicola, which is structurally related to Candida antarctica lipase A. A knockout strain for this enzyme does no longer produce lactonic sophorolipids, prompting us to believe that this protein is the missing S. bombicola lactone esterase (SBLE). SBLE catalyzes a rather unusual reaction, i.e., an intramolecular esterification (lactonization) of acidic sophorolipids in an aqueous environment, which raised questions about its activity and mode of action. Here, we report the heterologous production of this enzyme in Pichia pastoris and its purification in a two-step strategy. Purified recombinant SBLE (rSBLE) was used to perform HPLC and liquid chromatography mass spectrometry (LCMS)-based assays with different sophorolipid mixtures. We experimentally confirmed that SBLE is able to perform ring closure of acetylated acidic sophorolipids. This substrate was selected for rSBLE kinetic studies to estimate the apparent values of K (m) . We established that rSBLE displays optimal activity in the pH range of 3.5 to 6 and has an optimal temperature in the range of 20 to 50 A degrees C. Additionally, we generated a rSBLE mutant through site-directed mutagenesis of Ser(194) in the predicted active site pocket and show that this mutant is lacking the ability to lactonize sophorolipids. We therefore propose that SBLE operates via the common serine hydrolase mechanism in which the catalytic serine residue is assisted by a His/Asp pair