ADAMTS4 Levels Research Articles

Metalloproteinase ADAMTS-1 but not ADAMTS-5 is manifold overexpressed in neurodegenerative disorders as Down syndrome, Alzheimer's and Pick's disease

ADAMTS-1 is a disintegrin and metalloproteinase with thrombospondin 1 (TSP1)-like motifs with ubiquitous though variable expression. Natural substrates of this protease are proteoglycans as aggrecan and versican and null mutant mice propose a role for growth, fertility, organ structure and function. As the gene for this protein is encoded on chromosome 21 and maybe overexpressed due to the gene dosage hypothesis based upon the presence of a third chromosome in trisomy 21, we decided to study expression in Down syndrome (DS) brain and used brains of patients with Alzheimer's (AD) and Pick's disease (PD) as controls. Frontal cortex of controls, DS, AD and PD were homogenized and extracted proteins were used for immunoblotting using antibodies against ADAMTS-1 and ADAMTS-5. ADAMTS-1-immunoreactivity was manifold increased in brain with DS and neurodegeneration, whereas ADAMTS-5 levels were comparable. Overexpression of this metalloproteinase maybe specifically involved in proteoglycan degradation and handling in brain of patients with neurodegenerative disease which in turn may lead to or reflect pathological lesions in DS, AD and PD brain. The manifold overexpression of ADAMTS-1 may be used as marker protein for neurodegeneration.

Effects of transforming growth factor-β on aggrecanase production and proteoglycan degradation by human chondrocytes in vitro

Objective: Aggrecan is degraded by Aggrecanases (ADAMTS-4 and –5) and MMPs, which cleave its core protein at different sites. Transforming growth factor (TGF)β is known to stimulate matrix formation in cartilage, and ADAMTS-4 production in synoviocytes. The aim of this in-vitro study was to examine the effects of TGFβ on aggrecanase production in human cartilage. Design: Expression of ADAMTS-4 and -5 in chondrocyte cultures from normal or osteoarthritic cartilage was studied at mRNA level by RT-PCR. Aggrecanase activity was examined by western blot of aggrecanase-generated neoepitope NITEGE, and by measure of proteoglycan degradation in cartilage explants. Results: TGFβ strongly increased mRNA levels of ADAMTS-4, while ADAMTS-5 was expressed in a constitutive way in chondrocytes from normal and osteoathritic cartilage. TGFβ also increased NITEGE levels and proteoglycan degradation. Addition of an aggrecanase inhibitor blocked the increase of NITEGE, and partially inhibited proteoglycan degradation. Conclusions: TGFβ stimulates ADAMTS-4 expression and aggrecan degradation in cartilage. This catabolic action seems to be partially mediated by aggrecanases. It is, therefore, proposed that the role of TGFβ in cartilage matrix turnover is not limited to anabolic and anti-catabolic actions, but also extends to selective degradation of matrix components such as aggrecan.

Meiotic and developmental competence of bovine oocytes after induction of different levels of intracellular cAMP during IVM

Porcine IVF faces various problems such as incomplete cytoplasmic maturation of the oocyte and polyspermy. Previous studies proved the importance of cAMP in regulating nuclear and cytoplasmic maturation of oocytes. This study investigated the effect of the cAMP-modulating agents 3-isobutyl-1-methylxanthine (IBMX) and dibutyryl cAMP sodium salt (dbcAMP) on several parameters during in vitro production of porcine embryos. First, we wanted to see if oocyte collection in IBMX could meiotically arrest oocytes and, as such, improve synchronization of nuclear and cytoplasmic maturation. To this end, cumulus–oocyte complexes (COCs) were collected from gilts in HEPES-buffered Tyrode balanced salt solution medium with 0.5-mM IBMX or without IBMX. At the end of oocyte collection, the effect of IBMX on chromatin configuration was evaluated. However, no differences could be observed in nuclear configuration between IBMX− and IBMX+ oocytes (P > 0.05). Second, we added dbcAMP during IVM to improve cytoplasmic maturation and evaluated cumulus expansion (lack of adhesion), a disintegrin and metalloproteinase with thrombospondin-like repeats (ADAMTS-1) levels in cumulus cells, fertilization, and blastocyst rates. Cumulus–oocyte complexes were matured in modified North Carolina State University medium 37 with or without 1-mM dbcAMP. Frozen-thawed, epididymal, boar spermatozoa were used for IVF. After IVF, presumed zygotes were cultured for 7 days in North Carolina State University medium 23. Penetration rate decreased in dbcAMP+ (57.3%) compared with dbcAMP− (67.8%), but the polyspermy rate also decreased (43.3% vs. 53.4%, respectively) leading to an increased normal fertilization rate (56.7% vs. 46.6%, respectively; P < 0.05). Only 7.2% of the COCs showed adhesion in dbcAMP+ which was lower than 15.7% in dbcAMP− (P < 0.05) probably because of an upregulation of the ADAMTS-1 protein by dbcAMP. When the adherent oocytes were removed during maturation, no difference could be detected between the blastocyst rate of dbcAMP− and dbcAMP+ (17.1% and 21.0% on Day 7, respectively; P > 0.05). In conclusion, the use of IBMX during collection did not cause a meiotic arrest. Using dbcAMP during IVM caused a greater normal fertilization rate, a lower rate of adherent COCs during IVM, higher levels of ADAMTS-1 in cumulus cells, and an equal blastocyst rate after screening out adherent COCs. These findings contribute to a better understanding of cAMP involvement in porcine oocyte maturation and provide a basis to develop an improved system with less polyspermy and higher blastocyst rates.