Anna Galicka

The influence of selected flavonoids from the leaves of Cirsium palustre (L.) Scop. on collagen expression in human skin fibroblasts.

Ten flavonoids belonging to the subclasses of flavones, flavanones and aurones were isolated from methanolic extract of Cirsium palustre leaves after multistep chromatographic separation. Their structures were elucidated with spectroscopic methods. All compounds, except for luteolin 7‐O‐glucoside, were isolated for the first time. Four compounds—eriodictyol 7‐O‐glucoside (6), 6‐hydroxyluteolin 7‐O‐glucoside (11), scutellarein 7‐O‐glucoside (12) and pedalitin (14)—were tested for their effect on collagen expression in normal human dermal fibroblasts. Among them, compound 11 at 40 μM and compound 14, at all concentrations used (1, 20, 40 μM), significantly enhanced the level of total collagen secreted into the medium. Furthermore, compound 11 significantly stimulated type I collagen expression, whereas compound 14 activated type I and III collagen expression at the mRNA level, depending on concentration. MMP‐2 activity was inhibited by all study compounds, with the greatest effect recorded with compound 14 at 20 μM. The lack of effect on collagen content in the medium of compound 6‐ and compound 12‐treated cells, besides an increase in COL1A1 and COL1A2 expression, might be caused by diminished expression of HSP47 gene, resulting in decreased procollagen secretion. Future study of compounds 11 and 14 for their potential therapeutic use in conditions connected with collagen biosynthesis deficiency is required. Copyright

Comparative studies of osteoblast and fibroblast type I collagen in a patient with osteogenesis imperfecta type IV

The expression of type I collagen has been compared in fibroblast and osteoblast cultures of a patient with moderately severe osteogenesis imperfecta (OI) type IV, with respect to control cells. Electrophoretic analysis of type I collagen showed that both OI osteoblasts and fibroblasts synthesized normal chains and chains with delayed migration. However, the osteoblasts contained a higher proportion of abnormal chains than fibroblasts from the proband. Pulse‐chase experiments showed that the trimers containing abnormal chains were cleared more rapidly from osteoblasts than fibroblasts. Moreover, the collagen secreted by OI osteoblasts had thermal stability 1°C higher than collagen secreted by OI fibroblasts. These results suggest that the abnormal collagen in osteoblasts may be more resistant to intra‐ and extracellular degradation and may thus have better survival than in fibroblasts. This finding could have implications for understanding the clinical phenotype of OI. Copyright

Association between Vitamin D Receptor Polymorphism and Serum Vitamin D Levels in Children with Low-Energy Fractures.

Objective: Fractures of bones, especially forearm fractures, are very common in children and their number is increasing. This study was designed to determine the impact of vitamin D serum levels and vitamin D receptor (VDR) polymorphisms on the occurrence of low-energy fractures in children. Methods: The study group consisted of 100 children with clinically relevant bone fractures and a control group consisted of 127 children without fractures. Total vitamin D [25(OH)D3 plus 25(OH)D2] serum concentrations were evaluated in every patient. Genotypes for 4 restriction fragment length polymorphisms of the vitamin D receptor gene (FokI, ApaI, TaqI, and BsmI) were determined by standard polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) techniques. Results: Differences in concentrations of vitamin D were observed between the group with bone fractures (median = 12 ng/ml) and the control group (median = 16 ng/ml; p = 0.000044). Higher levels of vitamin D reduced the risk of fracture by 1.06 times (p = 0.0005). No impact of particular VDR polymorphism on the occurrence of low-energy fractures in children was detected. However, there were significant differences in the prevalence of FokI polymorphism genotypes between the fracture and control groups (p = 0.05). Furthermore, the recessive “aa” genotype of ApaI polymorphism and the dominant “TT” genotype of TaqI polymorphism were associated with higher levels of vitamin D (p = 0.005 and p = 0.036, respectively). Conclusions: Vitamin D deficiency is an independent risk factor for fractures in children. ApaI polymorphism recessive “aa” and TaqI polymorphism dominant “TT” genotypes are associated with higher levels of vitamin D in serum.

Gly511 to Ser substitution in the COL1A1 gene in osteogenesis imperfecta type III patient with increased turnover of collagen

Osteogenesis imperfecta (OI) is a result of heterozygous mutations in the COL1A1 or COL1A2 genes, encoding type I procollagen chains. Here we described the molecular and biochemical defects detected in a case of severe type III OI. Cultured skin fibroblasts from the proband produced both normal and mutant type I collagen which was secreted into the medium. The mutation site was localized in α1(I)-CB3 by CNBr cleavage of collagen chains. Subsequent reverse transcription-PCR amplification and direct sequencing of single-stranded PCR product led to identification of G to A transition in the COL1A1 gene, resulting in Gly511Ser substitution in the a1 chain of type I collagen. The new mutation conforms to the chain-specific non-lethal microdomain of Gly to Ser substitutions in the genotype-phenotype map.We have found that biosynthesis of collagen was increased in OI cells to about 160% of the control value. However, the amount of collagen deposed to the insoluble matrix was decreased as compared to the control. This suggests increased degradation of collagen, since the collagenolytic activity of OI cells was increased. Furthermore, the activity of prolidase, which is a marker of collagen turnover, was increased in OI cells. In regulation of activity of the enzyme are involved β1 integrin and insulin-like growth factor (IGF) receptors. Western immunoblot analysis showed that the expressions of both receptors were markedly increased in OI cells. These results suggest that increase in activity of prolidase can be associated with increase in intensity of collagen metabolism in type III OI patient with identified new G511S mutation.

Phenotype variability in a daughter and father with mild osteogenesis imperfecta correlated with collagen and prolidase levels in cultured skin fibroblasts.

Studies of collagen biosynthesis and prolidase activity were performed on cultured skin fibroblasts obtained from a female patient and her father, who displayed variable phenotypes of mild osteogenesis imperfecta (OI). For comparison, the same studies were also performed on age-matched controls. Biosynthesis of collagen in fibroblasts of the less affected father was reduced to approximately 50% of control levels, whereas in cells of the more severely affected daughter, it was decreased to about 20% of control levels. Furthermore, the decrease in collagen synthesis in OI fibroblasts was accompanied by a parallel decrease in prolidase activity and expression of beta1 integrin and insulin-like growth factor-I (IGF-I) receptors recovered from the cells. Therefore, prolidase, as well as IGF-I and beta1 integrin receptors involved in collagen metabolism regulation, may represent important factors influencing OI phenotype.

Methylparaben‐induced decrease in collagen production and viability of cultured human dermal fibroblasts

Parabens owing to their many advantageous properties are widely applied in cosmetics, food products and pharmaceuticals. However, recent research results have shown that they possess the ability to accumulate in the human body and exert many adverse effects. In this study, the impact of methylparaben (MP) as the most frequently used preservative in cosmetics, on human dermal fibroblasts and collagen production was evaluated. In cells treated with 0.01, 0.03 and 0.05% MP a dose‐dependent decrease in collagen biosynthesis was revealed, which was positively correlated with the activity of prolidase responsible for the recovery of proline. Consequently, the concentration of total collagen secreted into the medium was markedly diminished. A similar reduction in expression of the major skin collagen type I at both the protein and mRNA level as well as collagen type III and VI at the mRNA level was also detected. The decrease in the collagen level may result not only from the reduced synthesis but also increased degradation owing to MP‐induced activation of pro‐MMP‐2 (72 kDa). The increase in activity of MMP‐2 (66 kDa) was accompanied by a reduction in the inhibitory activity of TIMP‐2. In addition, an inhibitory effect of MP on cell survival and proliferation was revealed in this study. The increased expression and nuclear translocation of caspase‐3 as well as increased Bax and decreased Bcl‐2 expression may suggest MP‐induced cell apoptosis. In summary, we have provided new data on the adverse effects of methylparaben on human dermal fibroblasts and the main structural protein of the skin. Further studies on the mechanisms responsible for its action are in progress. Copyright

Decrease of interleukin (IL)17A gene expression in leucocytes and in the amount of IL-17A protein in CD4+ T cells in children with Down Syndrome

BACKGROUND Down Syndrome is by far the most common and best known chromosomal disorder in humans. It expresses multiple systemic complications with both structural and functional defects as part of the clinical manifestation. The mechanisms of immune changes occurring in Down Syndrome are complex and include an extra gene copy of chromosome 21 and secondary dysregulation of numerous intercellular interactions. Recent studies suggest a role of interleukin 17A (IL-17A), a pro-inflammatory cytokine located on 6p12 chromosome, in the pathogenesis of inflammatory and autoimmune diseases. We aimed to analyze IL17A gene expression in peripheral white cells and IL-17A intracellular expression on CD4+ T-cells. METHODS The research was carried out on a group of 58 children aged 6-12 years including a group of 30 children with Down Syndrome (simple trisomy of chromosome 21 only) and a reference group of 28 healthy children. We evaluated gene IL17A expression using real-time PCR and intracellular IL-17A analyzed by flow cytometry. RESULTS We found significantly decreased gene expression in white cells and significantly decreased expression of IL-17A levels on CD4+ T-cells in Down Syndrome. CONCLUSIONS Our data indicate that decreased IL-17A expression may play a significant role in the etiology of infections in Down Syndrome. Moreover, we demonstrated that in Down Syndrome the other gene located outside the extra chromosome 21 is also affected.

Beneficial impact of zinc supplementation on the collagen in the bone tissue of cadmium-exposed rats: Impact of zinc on collagen in cadmium-exposed rats

Cadmium (Cd) is a toxic metal that damages bone tissue by affecting its mineral and organic components. The organic matrix is mainly (90%) composed of collagen, which determines the biomechanical strength of bone. The aim of this study was to evaluate the effect of zinc (Zn) supplementation (30 or 60 mg l–1) under moderate and relatively high exposure to Cd (5 and 50 mg l–1) on collagen in the rat tibia proximal epiphysis and diaphysis (regions abundant in trabecular and cortical bone, respectively). Significant decrease in collagen type I biosynthesis was found in both regions of the tibia in Cd‐treated rats, whereas the supplementation with Zn provided significant protection against this effect. Western blot confirmed the presence of the major type I collagen in the tibia epiphysis and diaphysis, but collagen type II was revealed only in the epiphysis. Acetic acid‐ and pepsin‐soluble collagen concentration in the tibia epiphysis and diaphysis was significantly increased due to the exposure to Cd, whereas the supplementation with Zn protected, partially or totally, from these effects, depending on the used concentration. The supplementation with Zn also provided protection from unfavorable Cd impact on the maturation of the bone collagen, as the ratio of cross‐links to monomers was higher compared to the Cd‐treated group. This report confirms our previous findings on the preventive action of Zn against harmful effects of Cd on bone, but additionally, and to the best of our knowledge for the first time, explains the possible mechanism of the beneficial influence of this bioelement.

Mutations in the COL1A1 and COL1A2 genes associated with osteogenesis imperfecta (OI) types I or III

Although over 85% of osteogenesis imperfecta (OI) cases are associated with mutations in the procollagen type I genes (COL1A1 or COL1A2), no hot spots for the mutations were associated with particular clinical phenotypes. Eight patients that were studied here, diagnosed with OI by clinical standards, are from the Polish population with no ethnic background indicated. Previously unpublished mutations were found in six out of those eight patients. Genotypes for polymorphisms (Sp1 - rs1800012 and PvuII - rs412777), linked to bone formation and metabolism were determined. Mutations were found in exons 2, 22, 50 and in introns 13 and 51 of the COL1A1 gene. In COL1A2, one mutation was identified in exon 22. Deletion type mutations in COL1A1 that resulted in OI type I had no effect on collagen type I secretion, nor on its intracellular accumulation. Also, a single base substitution in I13 (c.904-9 G>T) was associated with the OI type I. The OI type III was associated with a single base change in I51 of COL1A1, possibly causing an exon skipping. Also, a missense mutation in COL1A2 changing Gly→Cys in the central part of the triple helical domain of the collagen type I molecule caused OI type III. It affected secretion of the heterotrimeric form of procollagen type I. However, no intracellular accumulation of procollagen chains could be detected. Mutation in COL1A2 affected its incorporation into procollagen type I. The results obtained shall help in genetic counseling of OI patients and provide a rational support for making informed, life important decisions by them and their families.

Differential effect of flavonoids on glycosaminoglycan content and distribution in skin fibroblasts of patients with type I osteogenesis imperfecta.

We recently reported that, in osteogenesis imperfecta (OI) type I with diminished type I collagen biosynthesis, flavonoids such as apigenin 7-O-glucuronide, apigenin 7-O-methylglucuronide and pectolinarin normalized the level of collagen type I without affecting total protein synthesis. In addition to collagen, glycosaminoglycans (GAGs) play an important role in the formation of a functional supramolecular complex in the extracellular matrix, and any changes in their content and/or composition may be involved in the OI phenotype. We previously detected a marked increase in sulphated GAG content in the OI fibroblasts of more severely affected patients (OI types II and III). These alterations were more pronounced in medium than in cells. Although, in OI type I cells, the increase observed in medium was much smaller (approximately 1.5-fold), it resulted in an increase of approximately 3-fold of the GAG to collagen type I ratio. Therefore, in the potential pharmacotherapy of OI type I with flavonoids, their effect on GAG level may be of importance. In the OI cells, some of the tested flavonoids applied at a concentration of 30 µM affected GAG content in quite the opposite way than type I collagen. Aglicones inhibiting collagen synthesis caused a marked increase in GAG concentration in medium, in contrast to the flavonoid glycosides, which exerted a stimulatory effect on type I collagen synthesis, but had a different effect on GAG content and distribution. Among these, apigenin 7-O-methylglucuronide did not affect GAG level or secretion, and thus may potentially be used in OI type I pharmacotherapy in patients with normal GAG content. However, in patients with increased concentrations of GAG, pectolinarin, which decreases GAG content by approximately 40%, may be more beneficial.