In the adult brain, the extracellular matrix (ECM) influences recovery after injury, susceptibility to mental disorders, and is in general a strong regulator of neuronal plasticity. The proteoglycan aggrecan is a core component of the condensed ECM structures termed perineuronal nets (PNNs), and the specific role of PNNs on neural plasticity remains elusive. Here, we genetically targeted the Acan gene encoding for aggrecan using a novel animal model. This allowed for conditional and targeted loss of aggrecan in vivo, which ablated the PNN structure and caused a shift in the population of parvalbumin-expressing inhibitory interneurons toward a high plasticity state. Selective deletion of the Acan gene in the visual cortex of male adult mice reinstated juvenile ocular dominance plasticity, which was mechanistically identical to critical period plasticity. Brain-wide targeting improved object recognition memory.SIGNIFICANCE STATEMENT The study provides the first direct evidence of aggrecan as the main functional constituent and orchestrator of perineuronal nets (PNNs), and that loss of PNNs by aggrecan removal induces a permanent state of critical period-like plasticity. Loss of aggrecan ablates the PNN structure, resulting in invoked juvenile plasticity in the visual cortex and enhanced object recognition memory.

• Klíčová slova
• aggrecan, inhibitory, interneuron, neuronal plasticity, parvalbumin, perineuronal nets,
• MeSH
• agrekany analýza   nedostatek   genetika   MeSH
• buněčné linie MeSH
• extracelulární matrix chemie   genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši transgenní MeSH
• myši MeSH
• nervová síť chemie   metabolismus   MeSH
• neuroplasticita fyziologie   MeSH
• světelná stimulace metody   MeSH
• zrakové korové centrum chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• agrekany MeSH

Proteoglycans extracted with 4 M guanidinium chloride from young (mean 20 years) or old (mean 79 years) macroscopically normal human articular cartilage were separated by density gradient centrifugation and Q-Sepharose chromatography and characterized by gradient gel SDS/PAGE and immunodetection before and after removal of glycosaminoglycan chains. The extracts contained two large populations of aggrecan, a population of small N-terminal aggrecan fragments, as well as decorin, biglycan and fibromodulin. The distribution of all these species in density gradient fractions has been determined. The large aggrecan populations comprised four different chondroitin sulphate-bearing core proteins while the population of smaller fragments comprised eight different components. The two smallest fragments (35 and 42 kDa), identified as the first globular domain of aggrecan (N-terminal) (G1) and containing no glycosaminoglycan, were detected only in extracts of old cartilage. A 55 and a 70 kDa fragment of G1 were present in both keratan sulphate-containing and non-keratan sulphate-containing forms. Four other fragments, each containing keratan sulphate epitopes, were identified and these contained either G1 epitopes (one 95 kDa species), or G1 and G2 epitopes (three species). These results have suggested that proteolytic processing at the N-terminus is more extensive than has previously been recognized and raises the possibility that more than one proteinase may be involved in aggrecan degradation in vivo. With the exception of the two smallest G1 fragments, the repertoire of proteoglycan fragments found in young and old human articular cartilage is essentially the same, although the relative abudnance of various species differed. The older tissue contains a larger proportion of C-terminally truncated aggrecan fragments and a significantly decreased content of decorin and biglycan.

• MeSH
• agrekany MeSH
• centrifugace - gradient hustoty MeSH
• dospělí MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• endopeptidasy metabolismus   MeSH
• extracelulární matrix - proteiny * MeSH
• katalýza MeSH
• kloubní chrupavka chemie   metabolismus   MeSH
• kyselina hyaluronová analýza   metabolismus   MeSH
• lektiny typu C MeSH
• lidé MeSH
• mladiství MeSH
• proteoglykany analýza   izolace a purifikace   metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• stárnutí metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• agrekany MeSH
• endopeptidasy MeSH
• extracelulární matrix - proteiny * MeSH
• kyselina hyaluronová MeSH
• lektiny typu C MeSH
• proteoglykany MeSH

CONTEXT: Heterozygous mutations in the aggrecan gene (ACAN) cause autosomal dominant short stature with accelerated skeletal maturation. OBJECTIVE: We sought to characterize the phenotypic spectrum and response to growth-promoting therapies. PATIENTS AND METHODS: One hundred three individuals (57 females, 46 males) from 20 families with autosomal dominant short stature and heterozygous ACAN mutations were identified and confirmed using whole-exome sequencing, targeted next-generation sequencing, and/or Sanger sequencing. Clinical information was collected from the medical records. RESULTS: Identified ACAN variants showed perfect cosegregation with phenotype. Adult individuals had mildly disproportionate short stature [median height, -2.8 standard deviation score (SDS); range, -5.9 to -0.9] and a history of early growth cessation. The condition was frequently associated with early-onset osteoarthritis (12 families) and intervertebral disc disease (9 families). No apparent genotype-phenotype correlation was found between the type of ACAN mutation and the presence of joint complaints. Childhood height was less affected (median height, -2.0 SDS; range, -4.2 to -0.6). Most children with ACAN mutations had advanced bone age (bone age - chronologic age; median, +1.3 years; range, +0.0 to +3.7 years). Nineteen individuals had received growth hormone therapy with some evidence of increased growth velocity. CONCLUSIONS: Heterozygous ACAN mutations result in a phenotypic spectrum ranging from mild and proportionate short stature to a mild skeletal dysplasia with disproportionate short stature and brachydactyly. Many affected individuals developed early-onset osteoarthritis and degenerative disc disease, suggesting dysfunction of the articular cartilage and intervertebral disc cartilage. Additional studies are needed to determine the optimal treatment strategy for these patients.

• MeSH
• agrekany genetika   MeSH
• antropometrie metody   MeSH
• brachydaktylie genetika   MeSH
• degenerace meziobratlové ploténky genetika   MeSH
• dítě MeSH
• dospělí MeSH
• fenotyp MeSH
• heterozygot MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace * MeSH
• mutační analýza DNA metody   MeSH
• nanismus farmakoterapie   genetika   MeSH
• osteochondritis dissecans vrozené   genetika   MeSH
• předškolní dítě MeSH
• rodokmen MeSH
• růst genetika   MeSH
• růstový hormon terapeutické užití   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• výhřez meziobratlové ploténky genetika   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• Názvy látek
• ACAN protein, human MeSH Prohlížeč
• agrekany MeSH
• růstový hormon MeSH

The toxic mechanisms of trichothecenes, including T-2 toxin and deoxynivalenol (DON), are closely related with their effects on protein synthesis. Increasing lines of evidence show that T-2 toxin can reduce the levels of tight junction proteins, and nuclear factor erythroid 2-related factor 2 (Nrf2) by disrupting cellular barriers and the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) and Nrf2/heme oxygenase (HO)-1 pathways. Moreover, it can inhibit aggrecan synthesis, thus causing Kashin-Beck disease. Regarding type B trichothecene, DON inhibits activation marker and β-catenin synthesis by acting on immune cells and the wingless/integrated (Wnt) pathway; it also inhibits cell proliferation and immune surveillance. In addition, DON has been shown to destroy tight junctions, glucose transport, and tumor endothelial marker 8, thus disturbing intestinal function and changing cell migration. This review summarizes the inhibitory effects of the trichothecenes T-2 toxin and DON on different protein synthesis, while discussing their underlying mechanisms. Focus is given to the effects of these toxins on tight junctions, aggrecan, activation markers, and hormones including testosterone under the influence of steroidogenic enzymes. This review can extend the current understanding of the effects of trichothecenes on protein synthesis and help to further understand their toxic mechanisms.

• Klíčová slova
• Deoxynivalenol, Inhibition, Protein synthesis, T-2 toxin, Toxic mechanism,
• MeSH
• agrekany MeSH
• faktor 2 související s NF-E2 MeSH
• T-2 toxin * toxicita   MeSH
• trichotheceny * toxicita   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• agrekany MeSH
• deoxynivalenol MeSH Prohlížeč
• faktor 2 související s NF-E2 MeSH
• T-2 toxin * MeSH
• trichotheceny * MeSH

Approx. 10% of the total proteoglycan content of normal young human articular cartilage was extracted under associative conditions with Dulbecco's PBS. Proteoglycans isolated from the extract by Q-Sepharose chromatography were separated by gel chromatography and characterized by gradient gel SDS/PAGE and immunoblotting. Three species of small proteoglycans, two main populations of aggrecan and a population of its smaller fragments were identified. The major populations of aggrecan contained chondroitin sulphate chains, all or part of the N-terminal G1 and G2 domains and, therefore, intact keratan sulphate domains. The larger population was estimated by gradient SDS/PAGE to have a molecular mass of approx. 600 kDa or greater. The second population had an apparent molecular mass of approx. 300-600 kDa. Core proteins derived from these populations of proteoglycans separated on SDS/PAGE into several clusters of bands in the range from 120 to approx. 360 kDa. The extract further contained smaller fragments which lacked chondroitin sulphate but reacted with antibodies against keratan sulphate, and against epitopes present in the G2 domain of aggrecan. The presence of the G2 domain in a broad range of populations of decreasing size indicated extensive cleavage of the aggrecan core protein within its chondroitin sulphate domain. These findings suggest that fragmentation of aggrecan probably occurs in vivo in normal articular cartilage of young individuals. Associative extracts also contained decorin, biglycan and fibromodulin. These were resolved from aggrecan by gel chromatography and identified by immunodetection.

• MeSH
• agrekany MeSH
• chemická frakcionace MeSH
• chondroitin chemie   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• extracelulární matrix - proteiny * MeSH
• gelová chromatografie MeSH
• imunoblotting MeSH
• kloubní chrupavka metabolismus   MeSH
• lektiny typu C MeSH
• lidé MeSH
• molekulová hmotnost MeSH
• monoklonální protilátky MeSH
• proteoglykany chemie   izolace a purifikace   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• agrekany MeSH
• chondroitin MeSH
• extracelulární matrix - proteiny * MeSH
• lektiny typu C MeSH
• monoklonální protilátky MeSH
• proteoglykany MeSH

Hyaluronan (HA) is a core constituent of perineuronal nets (PNNs) that surround subpopulations of neurones. The PNNs control synaptic stabilization in both the developing and adult central nervous system, and disruption of PNNs has shown to reactivate neuroplasticity. We investigated the possibility of memory prolongation by attenuating PNN formation using 4-methylumbelliferone (4-MU), an inhibitor of HA synthesis. Adult C57BL/6 mice were fed with chow containing 5% (w/w) 4-MU for 6 months, at a dose ~6.7 mg/g/day. The oral administration of 4-MU reduced the glycosaminoglycan level in the brain to 72% and the spinal cord to 50% when compared to the controls. Spontaneous object recognition test (SOR) performed at 2, 3, 6 and 7 months showed a significant increase in SOR score in the 6-months treatment group 24 h after object presentation. The effect however did not persist in the washout group (1-month post treatment). Immunohistochemistry confirmed a reduction of PNNs, with shorter and less arborization of aggrecan staining around dendrites in hippocampus after 6 months of 4-MU treatment. Histopathological examination revealed mild atrophy in articular cartilage but it did not affect the motor performance as demonstrated in rotarod test. In conclusion, systemic oral administration of 4-MU for 6 months reduced PNN formation around neurons and enhanced memory retention in mice. However, the memory enhancement was not sustained despite the reduction of PNNs, possibly due to the lack of memory enhancement training during the washout period. Our results suggest that 4-MU treatment might offer a strategy for PNN modulation in memory enhancement.

• Klíčová slova
• Extracellular matrix, Hyaluronan, Memory, Neuroplasticity, Perineuronal net,
• MeSH
• agrekany účinky léků   MeSH
• aplikace orální MeSH
• centrální nervový systém účinky léků   MeSH
• chování zvířat účinky léků   MeSH
• extracelulární matrix účinky léků   MeSH
• hymekromon aplikace a dávkování   farmakologie   MeSH
• kyselina hyaluronová metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• neuroplasticita účinky léků   MeSH
• oligodendroglie účinky léků   MeSH
• rozpoznávání (psychologie) účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• agrekany MeSH
• hymekromon MeSH
• kyselina hyaluronová MeSH

Bral2 is a link protein stabilizing the binding between lecticans and hyaluronan in perineuronal nets and axonal coats (ACs) in specific brain regions. Using the real-time iontophoretic method and diffusion-weighted magnetic resonance, we determined the extracellular space (ECS) volume fraction (α), tortuosity (λ), and apparent diffusion coefficient of water (ADCW ) in the thalamic ventral posteromedial nucleus (VPM) and sensorimotor cortex of young adult (3-6 months) and aged (14-20 months) Bral2-deficient (Bral2-/- ) mice and age-matched wild-type (wt) controls. The results were correlated with an analysis of extracellular matrix composition. In the cortex, no changes between wt and Bral2-/- were detected, either in the young or aged mice. In the VPM of aged but not in young Bral2-/- mice, we observed a significant decrease in α and ADCW in comparison with age-matched controls. Bral2 deficiency led to a reduction of both aggrecan- and brevican-associated perineuronal nets and a complete disruption of brevican-based ACs in young as well as aged VPM. Our data suggest that aging is a critical point that reveals the effect of Bral2 deficiency on VPM diffusion. This effect is probably mediated through the enhanced age-related damage of neurons lacking protective ACs, or the exhausting of compensatory mechanisms maintaining unchanged diffusion parameters in young Bral2-/- animals. A decreased ECS volume in aged Bral2-/- mice may influence the diffusion of neuroactive substances, and thus extrasynaptic and also indirectly synaptic transmission in this important nucleus of the somatosensory pathway.

• Klíčová slova
• Bral2, aging, diffusion, extracellular matrix, extracellular space,
• MeSH
• agrekany metabolismus   MeSH
• analýza rozptylu MeSH
• difuzní magnetická rezonance MeSH
• extracelulární matrix - proteiny nedostatek   genetika   MeSH
• extracelulární prostor diagnostické zobrazování   genetika   MeSH
• gangliová stimulancia farmakologie   MeSH
• kvartérní amoniové sloučeniny farmakologie   MeSH
• messenger RNA MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• neurony cytologie   účinky léků   MeSH
• novorozená zvířata MeSH
• proteiny nervové tkáně nedostatek   genetika   MeSH
• stárnutí fyziologie   MeSH
• techniky in vitro MeSH
• thalamus cytologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• agrekany MeSH
• extracelulární matrix - proteiny MeSH
• gangliová stimulancia MeSH
• Hapln4 protein, mouse MeSH Prohlížeč
• kvartérní amoniové sloučeniny MeSH
• messenger RNA MeSH
• proteiny nervové tkáně MeSH
• tetramethylammonium MeSH Prohlížeč

ACI is the most widely used cell-based surgical procedure for the repair of articular cartilage defects. The method is based on in vitro chondrocyte cultivation. Two different culture conditions, rotating-wall-vessel bioreactor and static culture, were assessed by their effect on the re-differentiation potential of human articular chondrocytes seeded into a hydrogel scaffold. Gene expression analysis of the tissue-engineered construct revealed no significant difference between the tested systems.

• MeSH
• agrekany metabolismus   MeSH
• bioreaktory MeSH
• buněčná diferenciace * genetika   MeSH
• buněčné kultury MeSH
• chondrocyty cytologie   metabolismus   transplantace   MeSH
• exprese genu MeSH
• kloubní chrupavka cytologie   metabolismus   MeSH
• kolagen typ II metabolismus   MeSH
• kolagen typu I metabolismus   MeSH
• kultivované buňky MeSH
• lidé MeSH
• PEG-DMA hydrogel MeSH
• tkáňové inženýrství metody   MeSH
• tkáňové podpůrné struktury MeSH
• versikany metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• agrekany MeSH
• kolagen typ II MeSH
• kolagen typu I MeSH
• PEG-DMA hydrogel MeSH
• versikany MeSH

Proteoglycans are considered integral structural components of tendon and ligament and have been implicated in the resistance of compressive forces, collagen fibrillogenesis, matrix remodelling and cell signalling. Several sequence variants within genes encoding proteoglycans were recently implicated in modulating anterior cruciate ligament ruptures (ACLR). This study aimed to test the previously implicated variants in proteoglycan and vascular epithelial growth factor encoding genes with risk of ACLR in a population from Poland. A case control genetic association study was conducted using DNA samples from 143 healthy participants without a history of ACL injuries (99 male and 44 females) (CON group) and 229 surgically diagnosed ACLR participants (158 males and 71 females). All samples were genotyped for the ACAN: rs1516797, BGN: rs1042103, rs1126499, DCN: rs516115 and VEGFA: rs699947 variants. Main findings included the (i) ACAN rs1516797 G/T genotype which was underrepresented in the CON group (CON: 36%, n=52, ACLR: 49%, n=112, p=0.017, OR=1.68, 95% CI 1.09 to 2.57) when all participants were investigated and (ii) the BGN rs1042103 A allele was significantly under-represented in the male CON group compared to the male ACLR group (CON: 39%, n=78, ACLR: 49%, n=156, p=0.029, OR=1.5, 95% CI 1.05 to 2.15). Furthermore, BGN inferred haplotypes were highlighted with altered ACLR susceptibility. Although the study implicated the ACAN and BGN genes (combination of genotype, allele and haplotype) in modulating ACLR susceptibility, several differences were noted with previous published findings.

• Klíčová slova
• Aggrecan, Anterior Cruciate Ligament, Biglycan, Decorin, Genetic Association Study, Haplotypes, Proteoglycans, Vascular Endothelial Growth Factor A,
• Publikační typ
• časopisecké články MeSH

Perineuronal nets (PNNs) are extracellular matrix structures surrounding neuronal sub-populations throughout the central nervous system, regulating plasticity. Enzymatically removing PNNs successfully enhances plasticity and thus functional recovery, particularly in spinal cord injury models. While PNNs within various brain regions are well studied, much of the composition and associated populations in the spinal cord is yet unknown. We aim to investigate the populations of PNN neurones involved in this functional motor recovery. Immunohistochemistry for choline acetyltransferase (labelling motoneurones), PNNs using Wisteria floribunda agglutinin (WFA) and chondroitin sulphate proteoglycans (CSPGs), including aggrecan, was performed to characterise the molecular heterogeneity of PNNs in rat spinal motoneurones (Mns). CSPG-positive PNNs surrounded ~70-80% of Mns. Using WFA, only ~60% of the CSPG-positive PNNs co-localised with WFA in the spinal Mns, while ~15-30% of Mns showed CSPG-positive but WFA-negative PNNs. Selective labelling revealed that aggrecan encircled ~90% of alpha Mns. The results indicate that (1) aggrecan labels spinal PNNs better than WFA, and (2) there are differences in PNN composition and their associated neuronal populations between the spinal cord and cortex. Insights into the role of PNNs and their molecular heterogeneity in the spinal motor pools could aid in designing targeted strategies to enhance functional recovery post-injury.

• Klíčová slova
• alpha motoneurone, chondroitin sulphate proteoglycans, gamma motoneurone, perineuronal nets, spinal cord,
• MeSH
• cholin-O-acetyltransferasa metabolismus   MeSH
• chondroitinsulfát proteoglykany metabolismus   MeSH
• extracelulární matrix - proteiny metabolismus   MeSH
• extracelulární matrix metabolismus   MeSH
• krysa rodu Rattus MeSH
• mícha cytologie   metabolismus   MeSH
• motorické neurony cytologie   metabolismus   MeSH
• neuroplasticita MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cholin-O-acetyltransferasa MeSH
• chondroitinsulfát proteoglykany MeSH
• extracelulární matrix - proteiny MeSH