Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of...Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of epiphyseal, articular and rib chondrocytes. Methods Sulfate GAG content in extracellular matrix of three chondrocytes was measured by the modified dimethylmethylene blue (DMB) method. The changes of the toluidine blue (TB) stain of chondrocytes were observed by light microscope. Results Primary chondrocytes had the highest content of sulfate GAG in the extracellular matrix, ie, epiphyseal chondrocytes reached ( 70. 12 ± 7. 72 )μg/cm2, articular chondrocytes (92.00 ± 10.15) μg/cm2 and rib chondrocytes (80.61 ± 11. 40) μg/cm2, respectively. On the third pasage chondrocytes, epiphyceal chondrocytes decreased to (53.27 ± 9. 50 ) μg/cm2, articular chondrocytes to (63.88 ± 11.92) μg/cm2 and rib chondrocytes to (58.94 ±8.21) μg/cm2, respectively. The change of TB in every passage展开更多
Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and...Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.展开更多
Glycosaminoglycans(GAGs)are a class of linear polysaccharides,consisting of alternating disaccharide sequences of uronic acid and hexosamines(or galactose)with and without sulfation.They can interact with various prot...Glycosaminoglycans(GAGs)are a class of linear polysaccharides,consisting of alternating disaccharide sequences of uronic acid and hexosamines(or galactose)with and without sulfation.They can interact with various proteins,such as growth factors,receptors and cell adhesion molecules,endowing these with various biological and pharmacological activi-ties.Such activities make GAGs useful in health care products and medicines.Currently,all GAGs,with the exception of hyaluronan,are produced by extraction from animal tissues.However,limited availability,poor control of animal tissues,impurities,viruses,prions,endotoxins,contamination and other problems have increased the interest in new approaches for GAG production.These new approaches include GAGs production by chemical synthesis,chemoenzymatic synthesis and metabolic engineering.One chemically synthesized heparin pentasaccharide,fondaparinux sodium,is in clinical use.Mostly,hyaluronan today is prepared by microbial fermentation,largely replacing hyaluronan from rooster comb.The recent gram scale chemoenzymatic synthesis of a heparin dodecasaccharide suggests its potential to replace currently used animal-sourced low molecular weight heparin(LMWH).Despite these considerable successes,such high-tech approaches still cannot meet worldwide demands for GAGs.This review gives a brief introduction on the manufacturing of unfractionated and low molecular weight heparins,the chemical synthesis and chemoenzymatic synthesis of GAGs and focuses on the progress in the bioengineered preparation of GAGs,particularly heparin.展开更多
Chondroitin sulfate(CS) B and T are rare subtypes of CS,which are scare in nature.There are also limited synthetic methods to prepare them.Here we report an ingenious semisynthetic approach to prepare a library of dis...Chondroitin sulfate(CS) B and T are rare subtypes of CS,which are scare in nature.There are also limited synthetic methods to prepare them.Here we report an ingenious semisynthetic approach to prepare a library of disaccharides,tetrasaccharides and hexasaccharides of CS-B and CS-T based on the acid or enzymatic degradation of natural CS polysaccharide in 9 or 10 steps.Our approach is the shortest synthetic route toward size-defined CS-B and CS-T oligosaccharides reported to date.In addition,a regioselective protection method of hydroxyls is highlighted,which has achieved the regioselective protection of 4 hydroxyl groups among 7 equatorial hydroxyl groups.By preparing size-defined rare CS oligosaccharides from commercially available natural CS polysaccharides,this strategy has the potential to meet the need of rare natural oligosaccharides.展开更多
Arsenic,a known environmental carcinogen,disrupts intestinal homeostasis,posing a significant threat to human health.Mitigating its toxic effects is crucial,and this study explores the potential of swim bladder sulfat...Arsenic,a known environmental carcinogen,disrupts intestinal homeostasis,posing a significant threat to human health.Mitigating its toxic effects is crucial,and this study explores the potential of swim bladder sulfated glycosaminoglycan(SBSG)in achieving this.Our previous in vitro studies have shown that SBSG to ameliorate arsenic-induced damage in intestinal epithelial cells,but its in vivo effects remain elusive.The current investigation demonstrates that SBSG exhibits a beneficial prebiotic action in vivo,regulating gut microbiota,metabolites,and intestinal barrier function to counter arsenic's adverse effects.Specifically,SBSG regulates microbiota composition,suppressing pathogenic species like Alistipes and Candidatus_Saccharimonas while promoting beneficial ones such as Ruminococcus and Akkermansia.In the colon,SBSG fermentation enhances the production of short-chain fatty acids(SCFAs),leading to the upregulation of GPR43,GPR109A,and Olfr78 receptors.Additionally,SBSG strengthens the intestinal barrier by increasing the expression of Claudin-1,Occludin,and ZO-1,and enhances mucin gene expression(MUC-1 and MUC-2)to address chemical barrier disruptions.Immunologically,SBSG modulates the RORγt/Foxp3 pathway and the TLR4/My D88/NF-κB signaling cascade,regulating the immune barrier.These findings suggest that SBSG could be a promising prebiotic candidate for maintaining intestinal health and may serve as a dietary supplement or adjunct in heavy metal detoxification therapies.展开更多
Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central n...Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.展开更多
Litter size and birth weights are limited by uterine capacity, defined as the ability of the uterus to maintain the appropriate development of some number of conceptuses. Uterine capacity is the result of the combined...Litter size and birth weights are limited by uterine capacity, defined as the ability of the uterus to maintain the appropriate development of some number of conceptuses. Uterine capacity is the result of the combined effects of uterine, placental and embryo/fetal function. The number of living conceptuses that the uterus is capable of supporting is greater during early gestation compared to later gestation. Plots of log fetal weight versus log placental weight also indicate that fetal weights are less sensitive to reduced placental weight （and therefore reduced intrauterine space） in early gestation compared to late gestation. However, even in late gestation, mechanisms still exist that maintain fetal growth when the size of the placenta is reduced. One such mechanism is likely to be improved development of the folded placental-epithelial/maternal-epithelial bilayer. Fold depth, and therefore the maternal fetal interactive surface, increases as gestation advances and is greater in placenta from smal fetuses. On the fetal side of the placenta, the epithelial bilayer is embedded in stromal tissue. Glycosaminoglycans are major components of stroma, including hyaluronan and heparan sulfate. Hyaluronidases and heparanases are present within placental tissues, and likely play roles in modification of stromal components to facilitate fold development. Glycosaminoglycans are polymers of forms of glucose （glucosamine, glucuronic acid, iduronic acid） suggesting that glycosaminoglycan synthesis may compete with the glucose needs of the developing fetus. Pig conceptuses are fructogenic, such that a substantial portion of glucose transferred from mother to fetus is converted to fructose. Fructose is an intermediate product in the synthesis of glucosamine from glucose, and glucosamine is linked to regulation of trophoblast cell proliferation through regulation of mTOR. These findings suggest a link between glucose, fructose, glucosamine synthesis, GAG production, and placental morphogenesis, but the details of these interactions remain unclear. In addition, recent placental epithelial transcriptome analysis identified several glucose, amino acid, lipid, vitamin, mineral and hormone transporter mechanisms within the placenta. Further elucidation of mechanisms of placental morphogenesis and solute transport could provide clues to improving nutrient transport to the pig fetus, potentially increasing litter size and piglet birth weights.展开更多
Glycosaminoglycans(GAGs) play a significant role in various aspects of cell physiology.These are complex polymeric molecules characterized by disaccharides comprising of uronic acid and amino sugar.Compounded to the h...Glycosaminoglycans(GAGs) play a significant role in various aspects of cell physiology.These are complex polymeric molecules characterized by disaccharides comprising of uronic acid and amino sugar.Compounded to the heterogeneity,these are variously sulfated and epimerized depending on the class of GAG.Among the various classes of GAG,namely,chondroitin/dermatan sulfate,heparin/heparan sulfate,keratan sulfate and hyaluronic acid(HA),only HA is non-sulfated.GAGs are known to undergo remodeling in various tissues during various pathophysiological conditions,diabetes mellitus being one among them.These changes will likely affect their structure thereby impinging on their functionality.Till date,diabetes has been shown to affect GAGs in organs such as kidney,liver,aorta,skin,erythrocytes,etc.to name a few,with deleterious consequences.One of the mainstays in the treatment of diabetes is though dietary means.Various dietary factors are known to play a significant role in regulating glucose homeostasis.Furthermore,in recent years,there has been a keen interest to decipher the role of dietary factors on GAG metabolism.This review focuses on the remodeling of GAGs in various organs during diabetes and their modulation by dietary factors.While effect of diabetes on GAG metabolism has been worked out quite a bit,studies on the role of dietary factors in their modulation has been few and far between.We have tried our best to give the latest reports available on this subject.展开更多
In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the ...In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear.The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM.Predominant components of the normal glomerular extracellular matrix(ECM)include glycosaminoglycans,proteoglycans,laminins,fibronectin-1,and several types of collagen.In patients with diabetes,multiorgan composition of extracellular tissues is anomalous,including the kidney,so that the constitution and arrangement of glomerular ECM is profoundly altered.In patients with diabetic kidney disease(DKD),the global quantity of glomerular ECM is increased.The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented,compared to control subjects.The concentration of mesangial fibronectin-1 varies depending on the stage of DKD.Mesangial type III collagen is abundant in patients with DKD,unlike normal kidneys.The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease.The GBM contains lower amount of type IV collagen in DKD compared to normal tissue.Further,genetic variants in theα3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease.Human cellular models of glomerular cells,analyses of human glomerular proteome,and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.展开更多
Mucopolysaccharidosis type II （MPS II） is a rare X-linked disorder caused by alterations in the iduronate-2-sulfatase （IDS） gene. In this study, IDS activity in peripheral mononuclear blood monocytes （PMBCs） was...Mucopolysaccharidosis type II （MPS II） is a rare X-linked disorder caused by alterations in the iduronate-2-sulfatase （IDS） gene. In this study, IDS activity in peripheral mononuclear blood monocytes （PMBCs） was measured with a fluorimetric enzyme assay. Urinary glycosaminoglycans （GAGs） were quantified using a colorimetric assay. All IDS exons and intronic flanks were bidirectionally sequenced. A total of 15 mutations （all exonic region） were found in 17 MPS II patients. In this cohort of MPS II patients, all alterations in the IDS gene were caused by point nucleotide substitutions or small deletions. Mutations p.Arg88His and p.Arg172＊ occurred twice. All mu- tations were inherited except for p.Gly489Alafs＊7, a germline mutation. We found four new mutations （p.Ser142Phe, p.Arg233Gly, p.Glu430＊, and p.Ile360Tyrfs＊31）. In Epstein-Barr virus （EBV）-immortalized PMBCs derived from the MPS II patients, no IDS protein was detected in case of the p.Ser142Phe and p.Ile360Tyrfs＊31 mutants. For p.Arg233Gly and p.Glu430＊, we observed a residual expression of IDS. The p.Arg233Gly and p.Glu430＊ mutants had a residuary enzymatic activity that was lowered by 14.3 and 76-fold, respectively, compared with healthy controls. This observation may help explain the mild disease phenotype in MPS II patients who had these two mutations whereas the p.Ser142Phe and p.Ile360Tyrfs＊31 mutations caused the severe disease manifestation.展开更多
A single-center, open-label clinical study was conducted to evaluate the efficacy and safety of NEM<sup>®</sup> as a natural treatment for pain and stiffness associated with osteoarthritis of the k...A single-center, open-label clinical study was conducted to evaluate the efficacy and safety of NEM<sup>®</sup> as a natural treatment for pain and stiffness associated with osteoarthritis of the knee in an Italian population. NEM<sup>®</sup> brand eggshell membrane is a unique dietary supplement that contains naturally occurring glycosaminoglycans and proteins essential for maintaining healthy joints and connective tissues. Twenty-five subjects received oral NEM<sup>®</sup>, 500 mg once daily for four weeks. The primary outcome measure was to evaluate the mean effectiveness of NEM<sup>®</sup> in relieving general pain associated with moderate osteoarthritis of the knee at 10 and 30 days utilizing a 10-question, abbreviated questionnaire based on the WOMAC osteoarthritis questionnaire. Supplementation with NEM<sup>®</sup> produced a significant treatment response from baseline at both 10 days and 30 days for composite pain (40.6% reduction, p p p = 0.009;59.7% reduction, p < 0.001, respectively). There were no adverse events or serious adverse events reported during the study and the treatment was reported to be well tolerated by study participants. NEM<sup>®</sup> is an effective and safe natural therapeutic option for the treatment of both pain and stiffness associated with osteoarthritis of the knee. Supplementation with NEM<sup>®</sup>, 500 mg taken once daily, significantly reduced both pain and stiffness rapidly (10 days) and this effect continued to improve through 30 days. There was also a meaningful reduction in the amount of analgesic consumed on a weekly basis, which further enhanced patients’ safety.展开更多
Background:Tendinopathy alters the compositional properties of the Achilles tendon by increasing fluid and glycosaminoglycan content.It has been speculated that these changes may affect intratendinous pressure,but the...Background:Tendinopathy alters the compositional properties of the Achilles tendon by increasing fluid and glycosaminoglycan content.It has been speculated that these changes may affect intratendinous pressure,but the extent of this relationship remains unclear.Therefore,we aimed to investigate the impact of elevated fluid and glycosaminoglycan content on Achilles tendon intratendinous pressure and to determine whether hyaluronidase(HYAL) therapy can intervene in this potential relationship.Methods:Twenty paired fresh-frozen cadaveric Achilles tendons were mounted in a tensile-testing machine and loaded up to 5% strain.Intratendinous resting(at 0% strain) and dynamic pressure(at 5% strain) were assessed using the microcapillary infusion technique.First,intratendinous pressure was measured under native conditions before and after infusion of 2 mL physiological saline.Next,80 mg of glycosaminoglycans were administered bilaterally to the paired tendons.The right tendons were additionally treated with 1500 units of HYAL.Finally,both groups were retested,and the glycosaminoglycan content was analyzed.Results:It was found that both elevated fluid and glycosaminoglycan content resulted in higher intratendinous resting and dynamic pressures(p <0.001).HYAL treatment induced a 2.3-fold reduction in glycosaminoglycan content(p=0.002) and restored intratendinous pressures.Conclusion:The results of this study demonstrated that elevated fluid and glycosaminoglycan content in Achilles tendinopathy contribute to increased intratendinous re sting and dynamic pressures,which can be explained by the associated increased volume and reduced permeability of the tendon matrix,respectively.HYAL degrades glycosaminoglycans sufficiently to lower intratendinous pressures and may,therefore,serve as a promising treatment.展开更多
To investigate the role of cartilage alterations in the pathogenesis of the idiopathic femoral head necrosis, 3 components of glycosaminoglycans(GAG) in pathological and health cartilage, levels of hyaluronic acid(HA)...To investigate the role of cartilage alterations in the pathogenesis of the idiopathic femoral head necrosis, 3 components of glycosaminoglycans(GAG) in pathological and health cartilage, levels of hyaluronic acid(HA) in synovial fluid and serum were detected. The correlations among HA level in synovial fluid, serum and GAG content in cartilage were analyzed. The results showed that ①the three components of cartilage GAG in normal adults and children showed little difference; ②Compared with the normal autopsy specimens, steroid induced ANFH and Perthes disease specimens had significantly decreased GAG contents (P<0 025). In the former ones, sulfate radical content had no obvious reduction in Ficat Ⅱ (P>0 05), but it decreased significantly (P<0 05) in Ficat Ⅲ, while hexosamine decreased sharply in Ficat Ⅱ and had no marked alternation in Ficat Ⅲ. And hexuronic acid fell sharply during Ficat Ⅱ and Ficat Ⅲ (P<0 05). Serum level of HA did not have obvious changes until Ficat Ⅲ. HA level in synovial fluid decreased extremely in Ficat Ⅲ in contrast to Ficat Ⅱ and normal controls (P<0 05). Moreover, there was no correlation between levels of HA in serum and in synovial fluid (P>0 05); ③Children suffered from Perthes disease had a much higher level of HA in serum than the controls (P<0 01). HA level in serum led an inverse correlation with that in synovial fluid. (r=-0 663,P<0 05);④There was a positive correlation between HA level in synovial fluid and GAG content in both steroid induced ANFH and Perthes disease. GAG content was positive correlated with HA level in serum of Perthes disease, whereas, there was no correlation between them in steroid induced ANFH. The results suggest that:①GAG content in affected hip decreased significantly in the early stage. It provides clinical theory basis for auxiliary treatment to cartilage in early stage; ②Sulfate radical depletion is the most conspicuous one of GAG changes in middle and late stage. It suggests that the sulfate radical glycoaminoglycans should be replenished in these stages; ③Measurement of the serum HA level is of no value in early diagnosis of steroid induced ANFH. To some extent serum levels of HA reflect biochemical changes in cartilage in Perthes disease.展开更多
Fourier transform infrared (FT-IR) spectroscopy, an organic molecule characterizing tool, is used here to differentiate young (36 ? 2.87 years) and aged (78 ? 1.25 years) skins, based on glycosaminoglycan (GAG) and pr...Fourier transform infrared (FT-IR) spectroscopy, an organic molecule characterizing tool, is used here to differentiate young (36 ? 2.87 years) and aged (78 ? 1.25 years) skins, based on glycosaminoglycan (GAG) and protein functional groups. Female breast mas-tectomy-skin, FT-IR spectroscopy revealed intensity differences that were quantified on GAG and protein standard curves, and assigned to the corresponding functional groups. Band intensity reductions at 78- years include: 34.37% (w/w) ?1259 - 1223 cm–1, sulfate (SO42–)/sulfonate (SO3–) S=O/phosphate (PO42?) P=O stretch?;32.00% (w/w) (1383-1262 cm-1, GAG- methyl C-H/C-C-H);and 35.60% (w/w) ?1738 - 1646 cm–1, C=O stretch: N-acetylated GAG’s, Amide I, and others?. Intensity increments at 78-years are 63.32% (w/w) (1636 - 1523 cm–1, Phe/Trp/Tyr-C=C, Amide II);27.02% (w/w) [1511 - 1457 cm–1, protein ?(CH2)/ ?(CH3) stretch];and 41.90% (w/w) (1218 - 1139 cm–1, Phe/Trp/Tyr C-H/C-N/C-C6H5 vibrations). The data speak to the power of FT-IR spectroscopy as a non-invasive tool to diagnose tissue disorders such as skin, liver, kidney or any other type that would require a noninvasive tool like FT-IR, to prevent further dam-age during the diagnosis. These results also demon-strate an age-mediated decrease of skin-GAG content, and GAG-N-acetylation, in addition to protein com-position concentration increments.展开更多
Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluro...Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan.展开更多
Versican belongs to the family of the large aggregating chondroitin sulfate proteoglycans located primarily within the extracellular matrix （ECM）. Versican, like other members of its family, has unique N- and C-term...Versican belongs to the family of the large aggregating chondroitin sulfate proteoglycans located primarily within the extracellular matrix （ECM）. Versican, like other members of its family, has unique N- and C-terminal globular regions, each with multiple motifs. A large glycosaminoglycan-binding region lies between them. This review will begin by outlining these structures, in the context of ECM proteoglycans. The diverse binding partners afforded to versican by virtue of its modular design will then be examined. These include ECM components, such as hyaluronan, type Ⅰ collagen, tenascin-R, fibulin-1, and -2, fibrillin-1, fibronectin, P- and L-selectins, and chemokines. Versican also binds to the cell surface proteins CD44, integrin β1, epidermal growth factor receptor, and P-selectin glycoprotein ligand-1. These multiple interactors play important roles in cell behaviour, and the roles of versican in modulating such processes are discussed.展开更多
Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 ...Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 yrs to 74 yrs were enrolled, gagCEST was acquired using a single-slice TSE sequence on a 3T. Saturation used a continuous rectangular RF pulse with B1=0.8 I^T and a fixed duration time =1100 ms. Sagittal image was obtained firstly without saturation pulse, and then saturated images were acquired at 52 offsets ranging from ＋0.i25 to ＋_7 parts per million （ppm）. MR T2 relaxivity map was acquired at the identical location. Six subjects were scanned twice to assess scan-rescan reproducibility. Results GagCEST intraclass correlation coefficient （ICC） of six subjects was 0.759 for nucleus pulposus （NP） and 0.508 for annulus fibrosus （AF）. Bland-Altman plots showed NP had a mean difference of 0.10% （95% limits of agreement： -3.02% to 3.22%）; while that of AF was 0.34% （95% limits of agreement： -2.28% to 2.95%）. For the 25 subjects, gag CEST in NP decreased as disc degeneration increased, with a similar trend to T2 relaxivity. Gag CEST of AF showed a better correlation with disc degeneration than T2 relaxivity. Conclusion GagCEST in NP and AF decreased as disc degeneration increased, while gagCEST in AF showed a better correlation than T2 relaxivity.展开更多
Esophageal squamous cell carcinoma(ESCC)is a highly malignant disease that has a poor prognosis.Its high lethality is mainly due to the lack of symptoms at early stages,which culminates in diagnosis at a late stage wh...Esophageal squamous cell carcinoma(ESCC)is a highly malignant disease that has a poor prognosis.Its high lethality is mainly due to the lack of symptoms at early stages,which culminates in diagnosis at a late stage when the tumor has already metastasized.Unfortunately,the common cancer biomarkers have low sensitivity and specificity in esophageal cancer.Therefore,a better understanding of the molecular mechanisms underlying ESCC progression is needed to identify novel diagnostic markers and therapeutic targets for intervention.The invasion of cancer cells into the surrounding tissue is a crucial step for metastasis.During metastasis,tumor cells can interact with extracellular components and secrete proteolytic enzymes to remodel the surrounding tumor microenvironment.Proteoglycans are one of the major components of extracellular matrix.They are involved in multiple processes of cancer cell invasion and metastasis by interacting with soluble bioactive molecules,surrounding matrix,cell surface receptors,and enzymes.Apart from having diverse functions in tumor cells and their surrounding microenvironment,proteoglycans also have diagnostic and prognostic significance in cancer patients.However,the functional significance and underlying mechanisms of proteoglycans in ESCC are not well understood.This review summarizes the proteoglycans that have been studied in ESCC in order to provide a comprehensive view of the role of proteoglycans in the progression of this cancer type.A long term goal would be to exploit these molecules to provide new strategies for therapeutic intervention.展开更多
Objective: To identify the mutations of iduronate-2-sulfatase (IDS) gene, to reveal its mutation features, and to establish a basis for genetic counseling and prenatal gene diagnosis of Hunter syndrome. Methods: Urine...Objective: To identify the mutations of iduronate-2-sulfatase (IDS) gene, to reveal its mutation features, and to establish a basis for genetic counseling and prenatal gene diagnosis of Hunter syndrome. Methods: Urine glycosaminoglycans (GAGs) assay, PCR and DNA sequencing were performed to detect mutation of IDS gene of the patient and his parents. Results: The result showed that the patient was: DS(++), HS(++), KS(-), CS(-), and that both of his parents were negative. A frame-shift deletion mutation (1062 del 16) was identified in exon 7 of the patient's IDS gene. His parents' genotypes were normal. Conclusion:The patient's mutation was not inherited by his parents but a novel one. The mutation probably altered the primary structure and tertiary structure of IDS enzyme protein remarkably and lowered the activity of IDS enzyme greatly. Therefore it is supposed to be the direct cause of the disorder.展开更多
文摘Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of epiphyseal, articular and rib chondrocytes. Methods Sulfate GAG content in extracellular matrix of three chondrocytes was measured by the modified dimethylmethylene blue (DMB) method. The changes of the toluidine blue (TB) stain of chondrocytes were observed by light microscope. Results Primary chondrocytes had the highest content of sulfate GAG in the extracellular matrix, ie, epiphyseal chondrocytes reached ( 70. 12 ± 7. 72 )μg/cm2, articular chondrocytes (92.00 ± 10.15) μg/cm2 and rib chondrocytes (80.61 ± 11. 40) μg/cm2, respectively. On the third pasage chondrocytes, epiphyceal chondrocytes decreased to (53.27 ± 9. 50 ) μg/cm2, articular chondrocytes to (63.88 ± 11.92) μg/cm2 and rib chondrocytes to (58.94 ±8.21) μg/cm2, respectively. The change of TB in every passage
基金supported by the National Natural Science Foundation of China,No.82002645China Postdoctoral Science Foundation,No.2022M722321Jiangsu Funding Program for Excellent Postdoctoral Talent,No.2022ZB552(all to YH)。
文摘Spinal cord injuries have overwhelming physical and occupational implications for patients.Moreover,the extensive and long-term medical care required for spinal cord injury significantly increases healthcare costs and resources,adding a substantial burden to the healthcare system and patients'families.In this context,chondroitinase ABC,a bacterial enzyme isolated from Proteus vulgaris that is modified to facilitate expression and secretion in mammals,has emerged as a promising therapeutic agent.It works by degrading chondroitin sulfate proteoglycans,cleaving the glycosaminoglycanchains of chondroitin sulfate proteoglycans into soluble disaccharides or tetrasaccharides.Chondroitin sulfate proteoglycans are potent axon growth inhibitors and principal constituents of the extracellular matrix surrounding glial and neuronal cells attached to glycosaminoglycan chains.Chondroitinase ABC has been shown to play an effective role in promoting recovery from acute and chronic spinal cord injury by improving axonal regeneration and sprouting,enhancing the plasticity of perineuronal nets,inhibiting neuronal apoptosis,and modulating immune responses in various animal models.In this review,we introduce the classification and pathological mechanisms of spinal cord injury and discuss the pathophysiological role of chondroitin sulfate proteoglycans in spinal cord injury.We also highlight research advancements in spinal cord injury treatment strategies,with a focus on chondroitinase ABC,and illustrate how improvements in chondroitinase ABC stability,enzymatic activity,and delivery methods have enhanced injured spinal cord repair.Furthermore,we emphasize that combination treatment with chondroitinase ABC further enhances therapeutic efficacy.This review aimed to provide a comprehensive understanding of the current trends and future directions of chondroitinase ABC-based spinal cord injury therapies,with an emphasis on how modern technologies are accelerating the optimization of chondroitinase ABC development.
基金This study was supported by China Scholarship Council(W.J.)the National Institutes of Health(DK111958 and CA231074)(F.Z.and R.J.L.).
文摘Glycosaminoglycans(GAGs)are a class of linear polysaccharides,consisting of alternating disaccharide sequences of uronic acid and hexosamines(or galactose)with and without sulfation.They can interact with various proteins,such as growth factors,receptors and cell adhesion molecules,endowing these with various biological and pharmacological activi-ties.Such activities make GAGs useful in health care products and medicines.Currently,all GAGs,with the exception of hyaluronan,are produced by extraction from animal tissues.However,limited availability,poor control of animal tissues,impurities,viruses,prions,endotoxins,contamination and other problems have increased the interest in new approaches for GAG production.These new approaches include GAGs production by chemical synthesis,chemoenzymatic synthesis and metabolic engineering.One chemically synthesized heparin pentasaccharide,fondaparinux sodium,is in clinical use.Mostly,hyaluronan today is prepared by microbial fermentation,largely replacing hyaluronan from rooster comb.The recent gram scale chemoenzymatic synthesis of a heparin dodecasaccharide suggests its potential to replace currently used animal-sourced low molecular weight heparin(LMWH).Despite these considerable successes,such high-tech approaches still cannot meet worldwide demands for GAGs.This review gives a brief introduction on the manufacturing of unfractionated and low molecular weight heparins,the chemical synthesis and chemoenzymatic synthesis of GAGs and focuses on the progress in the bioengineered preparation of GAGs,particularly heparin.
基金supported by the National Natural Science Foundation of China(Nos.81930097,82151223)the National Key R&D Program of China(Nos.2022YFF1203005,2022YFC2303700)。
文摘Chondroitin sulfate(CS) B and T are rare subtypes of CS,which are scare in nature.There are also limited synthetic methods to prepare them.Here we report an ingenious semisynthetic approach to prepare a library of disaccharides,tetrasaccharides and hexasaccharides of CS-B and CS-T based on the acid or enzymatic degradation of natural CS polysaccharide in 9 or 10 steps.Our approach is the shortest synthetic route toward size-defined CS-B and CS-T oligosaccharides reported to date.In addition,a regioselective protection method of hydroxyls is highlighted,which has achieved the regioselective protection of 4 hydroxyl groups among 7 equatorial hydroxyl groups.By preparing size-defined rare CS oligosaccharides from commercially available natural CS polysaccharides,this strategy has the potential to meet the need of rare natural oligosaccharides.
基金supported by Shenzhen Science and Technology Program(GJHZ20240218114715029)the National Natural Science Foundation of China(31972163)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2023A1515010005)Special funds for universities in Guangdong Province in the key areas of biomedicine and health(2023ZDZX2025)the Innovative Team Program of High Education of Guangdong Province(2021KCXTD021)。
文摘Arsenic,a known environmental carcinogen,disrupts intestinal homeostasis,posing a significant threat to human health.Mitigating its toxic effects is crucial,and this study explores the potential of swim bladder sulfated glycosaminoglycan(SBSG)in achieving this.Our previous in vitro studies have shown that SBSG to ameliorate arsenic-induced damage in intestinal epithelial cells,but its in vivo effects remain elusive.The current investigation demonstrates that SBSG exhibits a beneficial prebiotic action in vivo,regulating gut microbiota,metabolites,and intestinal barrier function to counter arsenic's adverse effects.Specifically,SBSG regulates microbiota composition,suppressing pathogenic species like Alistipes and Candidatus_Saccharimonas while promoting beneficial ones such as Ruminococcus and Akkermansia.In the colon,SBSG fermentation enhances the production of short-chain fatty acids(SCFAs),leading to the upregulation of GPR43,GPR109A,and Olfr78 receptors.Additionally,SBSG strengthens the intestinal barrier by increasing the expression of Claudin-1,Occludin,and ZO-1,and enhances mucin gene expression(MUC-1 and MUC-2)to address chemical barrier disruptions.Immunologically,SBSG modulates the RORγt/Foxp3 pathway and the TLR4/My D88/NF-κB signaling cascade,regulating the immune barrier.These findings suggest that SBSG could be a promising prebiotic candidate for maintaining intestinal health and may serve as a dietary supplement or adjunct in heavy metal detoxification therapies.
基金supported by the NIH(NS53470)the Kentucky Spinal Cord and Head Injury Research Trust(#10-11A)the Department of Defense,CDMRP(SC090248/W81XWH-10-1-0778)
文摘Proteoglycans in the central nervous system play integral roles as ＂traffic signals＂ for the direction of neurite outgrowth. This attribute of proteoglycans is a major factor in regeneration of the injured central nervous system. In this review, the structures of proteoglycans and the evidence suggesting their involvement in the response following spinal cord injury are presented. The review further describes the methods routinely used to determine the effect proteoglycans have on neurite outgrowth. The effects of proteoglycans on neurite outgrowth are not completely understood as there is disagreement on what component of the molecule is interacting with growing neurites and this ambiguity is chronicled in an historical context. Finally, the most recent findings suggesting possible receptors, interactions, and sulfation patterns that may be important in eliciting the effect of proteoglycans on neurite outgrowth are discussed. A greater understanding of the proteoglycan-neurite interaction is necessary for successfully promoting regeneration in the iniured central nervous system.
文摘Litter size and birth weights are limited by uterine capacity, defined as the ability of the uterus to maintain the appropriate development of some number of conceptuses. Uterine capacity is the result of the combined effects of uterine, placental and embryo/fetal function. The number of living conceptuses that the uterus is capable of supporting is greater during early gestation compared to later gestation. Plots of log fetal weight versus log placental weight also indicate that fetal weights are less sensitive to reduced placental weight （and therefore reduced intrauterine space） in early gestation compared to late gestation. However, even in late gestation, mechanisms still exist that maintain fetal growth when the size of the placenta is reduced. One such mechanism is likely to be improved development of the folded placental-epithelial/maternal-epithelial bilayer. Fold depth, and therefore the maternal fetal interactive surface, increases as gestation advances and is greater in placenta from smal fetuses. On the fetal side of the placenta, the epithelial bilayer is embedded in stromal tissue. Glycosaminoglycans are major components of stroma, including hyaluronan and heparan sulfate. Hyaluronidases and heparanases are present within placental tissues, and likely play roles in modification of stromal components to facilitate fold development. Glycosaminoglycans are polymers of forms of glucose （glucosamine, glucuronic acid, iduronic acid） suggesting that glycosaminoglycan synthesis may compete with the glucose needs of the developing fetus. Pig conceptuses are fructogenic, such that a substantial portion of glucose transferred from mother to fetus is converted to fructose. Fructose is an intermediate product in the synthesis of glucosamine from glucose, and glucosamine is linked to regulation of trophoblast cell proliferation through regulation of mTOR. These findings suggest a link between glucose, fructose, glucosamine synthesis, GAG production, and placental morphogenesis, but the details of these interactions remain unclear. In addition, recent placental epithelial transcriptome analysis identified several glucose, amino acid, lipid, vitamin, mineral and hormone transporter mechanisms within the placenta. Further elucidation of mechanisms of placental morphogenesis and solute transport could provide clues to improving nutrient transport to the pig fetus, potentially increasing litter size and piglet birth weights.
文摘Glycosaminoglycans(GAGs) play a significant role in various aspects of cell physiology.These are complex polymeric molecules characterized by disaccharides comprising of uronic acid and amino sugar.Compounded to the heterogeneity,these are variously sulfated and epimerized depending on the class of GAG.Among the various classes of GAG,namely,chondroitin/dermatan sulfate,heparin/heparan sulfate,keratan sulfate and hyaluronic acid(HA),only HA is non-sulfated.GAGs are known to undergo remodeling in various tissues during various pathophysiological conditions,diabetes mellitus being one among them.These changes will likely affect their structure thereby impinging on their functionality.Till date,diabetes has been shown to affect GAGs in organs such as kidney,liver,aorta,skin,erythrocytes,etc.to name a few,with deleterious consequences.One of the mainstays in the treatment of diabetes is though dietary means.Various dietary factors are known to play a significant role in regulating glucose homeostasis.Furthermore,in recent years,there has been a keen interest to decipher the role of dietary factors on GAG metabolism.This review focuses on the remodeling of GAGs in various organs during diabetes and their modulation by dietary factors.While effect of diabetes on GAG metabolism has been worked out quite a bit,studies on the role of dietary factors in their modulation has been few and far between.We have tried our best to give the latest reports available on this subject.
文摘In the glomeruli,mesangial cells produce mesangial matrix while podocytes wrap glomerular capillaries with cellular extensions named foot processes and tether the glomerular basement membrane(GBM).The turnover of the mature GBM and the ability of adult podocytes to repair injured GBM are unclear.The actin cytoskeleton is a major cytoplasmic component of podocyte foot processes and links the cell to the GBM.Predominant components of the normal glomerular extracellular matrix(ECM)include glycosaminoglycans,proteoglycans,laminins,fibronectin-1,and several types of collagen.In patients with diabetes,multiorgan composition of extracellular tissues is anomalous,including the kidney,so that the constitution and arrangement of glomerular ECM is profoundly altered.In patients with diabetic kidney disease(DKD),the global quantity of glomerular ECM is increased.The level of sulfated proteoglycans is reduced while hyaluronic acid is augmented,compared to control subjects.The concentration of mesangial fibronectin-1 varies depending on the stage of DKD.Mesangial type III collagen is abundant in patients with DKD,unlike normal kidneys.The amount of type V and type VI collagens is higher in DKD and increases with the progression of the disease.The GBM contains lower amount of type IV collagen in DKD compared to normal tissue.Further,genetic variants in theα3 chain of type IV collagen may modulate susceptibility to DKD and end-stage kidney disease.Human cellular models of glomerular cells,analyses of human glomerular proteome,and improved microscopy procedures have been developed to investigate the molecular composition and organization of the human glomerular ECM.
文摘Mucopolysaccharidosis type II （MPS II） is a rare X-linked disorder caused by alterations in the iduronate-2-sulfatase （IDS） gene. In this study, IDS activity in peripheral mononuclear blood monocytes （PMBCs） was measured with a fluorimetric enzyme assay. Urinary glycosaminoglycans （GAGs） were quantified using a colorimetric assay. All IDS exons and intronic flanks were bidirectionally sequenced. A total of 15 mutations （all exonic region） were found in 17 MPS II patients. In this cohort of MPS II patients, all alterations in the IDS gene were caused by point nucleotide substitutions or small deletions. Mutations p.Arg88His and p.Arg172＊ occurred twice. All mu- tations were inherited except for p.Gly489Alafs＊7, a germline mutation. We found four new mutations （p.Ser142Phe, p.Arg233Gly, p.Glu430＊, and p.Ile360Tyrfs＊31）. In Epstein-Barr virus （EBV）-immortalized PMBCs derived from the MPS II patients, no IDS protein was detected in case of the p.Ser142Phe and p.Ile360Tyrfs＊31 mutants. For p.Arg233Gly and p.Glu430＊, we observed a residual expression of IDS. The p.Arg233Gly and p.Glu430＊ mutants had a residuary enzymatic activity that was lowered by 14.3 and 76-fold, respectively, compared with healthy controls. This observation may help explain the mild disease phenotype in MPS II patients who had these two mutations whereas the p.Ser142Phe and p.Ile360Tyrfs＊31 mutations caused the severe disease manifestation.
文摘A single-center, open-label clinical study was conducted to evaluate the efficacy and safety of NEM<sup>®</sup> as a natural treatment for pain and stiffness associated with osteoarthritis of the knee in an Italian population. NEM<sup>®</sup> brand eggshell membrane is a unique dietary supplement that contains naturally occurring glycosaminoglycans and proteins essential for maintaining healthy joints and connective tissues. Twenty-five subjects received oral NEM<sup>®</sup>, 500 mg once daily for four weeks. The primary outcome measure was to evaluate the mean effectiveness of NEM<sup>®</sup> in relieving general pain associated with moderate osteoarthritis of the knee at 10 and 30 days utilizing a 10-question, abbreviated questionnaire based on the WOMAC osteoarthritis questionnaire. Supplementation with NEM<sup>®</sup> produced a significant treatment response from baseline at both 10 days and 30 days for composite pain (40.6% reduction, p p p = 0.009;59.7% reduction, p < 0.001, respectively). There were no adverse events or serious adverse events reported during the study and the treatment was reported to be well tolerated by study participants. NEM<sup>®</sup> is an effective and safe natural therapeutic option for the treatment of both pain and stiffness associated with osteoarthritis of the knee. Supplementation with NEM<sup>®</sup>, 500 mg taken once daily, significantly reduced both pain and stiffness rapidly (10 days) and this effect continued to improve through 30 days. There was also a meaningful reduction in the amount of analgesic consumed on a weekly basis, which further enhanced patients’ safety.
基金funded by Ghent University Hospital(FIKO21/TYPE2/013)。
文摘Background:Tendinopathy alters the compositional properties of the Achilles tendon by increasing fluid and glycosaminoglycan content.It has been speculated that these changes may affect intratendinous pressure,but the extent of this relationship remains unclear.Therefore,we aimed to investigate the impact of elevated fluid and glycosaminoglycan content on Achilles tendon intratendinous pressure and to determine whether hyaluronidase(HYAL) therapy can intervene in this potential relationship.Methods:Twenty paired fresh-frozen cadaveric Achilles tendons were mounted in a tensile-testing machine and loaded up to 5% strain.Intratendinous resting(at 0% strain) and dynamic pressure(at 5% strain) were assessed using the microcapillary infusion technique.First,intratendinous pressure was measured under native conditions before and after infusion of 2 mL physiological saline.Next,80 mg of glycosaminoglycans were administered bilaterally to the paired tendons.The right tendons were additionally treated with 1500 units of HYAL.Finally,both groups were retested,and the glycosaminoglycan content was analyzed.Results:It was found that both elevated fluid and glycosaminoglycan content resulted in higher intratendinous resting and dynamic pressures(p <0.001).HYAL treatment induced a 2.3-fold reduction in glycosaminoglycan content(p=0.002) and restored intratendinous pressures.Conclusion:The results of this study demonstrated that elevated fluid and glycosaminoglycan content in Achilles tendinopathy contribute to increased intratendinous re sting and dynamic pressures,which can be explained by the associated increased volume and reduced permeability of the tendon matrix,respectively.HYAL degrades glycosaminoglycans sufficiently to lower intratendinous pressures and may,therefore,serve as a promising treatment.
文摘To investigate the role of cartilage alterations in the pathogenesis of the idiopathic femoral head necrosis, 3 components of glycosaminoglycans(GAG) in pathological and health cartilage, levels of hyaluronic acid(HA) in synovial fluid and serum were detected. The correlations among HA level in synovial fluid, serum and GAG content in cartilage were analyzed. The results showed that ①the three components of cartilage GAG in normal adults and children showed little difference; ②Compared with the normal autopsy specimens, steroid induced ANFH and Perthes disease specimens had significantly decreased GAG contents (P<0 025). In the former ones, sulfate radical content had no obvious reduction in Ficat Ⅱ (P>0 05), but it decreased significantly (P<0 05) in Ficat Ⅲ, while hexosamine decreased sharply in Ficat Ⅱ and had no marked alternation in Ficat Ⅲ. And hexuronic acid fell sharply during Ficat Ⅱ and Ficat Ⅲ (P<0 05). Serum level of HA did not have obvious changes until Ficat Ⅲ. HA level in synovial fluid decreased extremely in Ficat Ⅲ in contrast to Ficat Ⅱ and normal controls (P<0 05). Moreover, there was no correlation between levels of HA in serum and in synovial fluid (P>0 05); ③Children suffered from Perthes disease had a much higher level of HA in serum than the controls (P<0 01). HA level in serum led an inverse correlation with that in synovial fluid. (r=-0 663,P<0 05);④There was a positive correlation between HA level in synovial fluid and GAG content in both steroid induced ANFH and Perthes disease. GAG content was positive correlated with HA level in serum of Perthes disease, whereas, there was no correlation between them in steroid induced ANFH. The results suggest that:①GAG content in affected hip decreased significantly in the early stage. It provides clinical theory basis for auxiliary treatment to cartilage in early stage; ②Sulfate radical depletion is the most conspicuous one of GAG changes in middle and late stage. It suggests that the sulfate radical glycoaminoglycans should be replenished in these stages; ③Measurement of the serum HA level is of no value in early diagnosis of steroid induced ANFH. To some extent serum levels of HA reflect biochemical changes in cartilage in Perthes disease.
文摘Fourier transform infrared (FT-IR) spectroscopy, an organic molecule characterizing tool, is used here to differentiate young (36 ? 2.87 years) and aged (78 ? 1.25 years) skins, based on glycosaminoglycan (GAG) and protein functional groups. Female breast mas-tectomy-skin, FT-IR spectroscopy revealed intensity differences that were quantified on GAG and protein standard curves, and assigned to the corresponding functional groups. Band intensity reductions at 78- years include: 34.37% (w/w) ?1259 - 1223 cm–1, sulfate (SO42–)/sulfonate (SO3–) S=O/phosphate (PO42?) P=O stretch?;32.00% (w/w) (1383-1262 cm-1, GAG- methyl C-H/C-C-H);and 35.60% (w/w) ?1738 - 1646 cm–1, C=O stretch: N-acetylated GAG’s, Amide I, and others?. Intensity increments at 78-years are 63.32% (w/w) (1636 - 1523 cm–1, Phe/Trp/Tyr-C=C, Amide II);27.02% (w/w) [1511 - 1457 cm–1, protein ?(CH2)/ ?(CH3) stretch];and 41.90% (w/w) (1218 - 1139 cm–1, Phe/Trp/Tyr C-H/C-N/C-C6H5 vibrations). The data speak to the power of FT-IR spectroscopy as a non-invasive tool to diagnose tissue disorders such as skin, liver, kidney or any other type that would require a noninvasive tool like FT-IR, to prevent further dam-age during the diagnosis. These results also demon-strate an age-mediated decrease of skin-GAG content, and GAG-N-acetylation, in addition to protein com-position concentration increments.
文摘Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan.
文摘Versican belongs to the family of the large aggregating chondroitin sulfate proteoglycans located primarily within the extracellular matrix （ECM）. Versican, like other members of its family, has unique N- and C-terminal globular regions, each with multiple motifs. A large glycosaminoglycan-binding region lies between them. This review will begin by outlining these structures, in the context of ECM proteoglycans. The diverse binding partners afforded to versican by virtue of its modular design will then be examined. These include ECM components, such as hyaluronan, type Ⅰ collagen, tenascin-R, fibulin-1, and -2, fibrillin-1, fibronectin, P- and L-selectins, and chemokines. Versican also binds to the cell surface proteins CD44, integrin β1, epidermal growth factor receptor, and P-selectin glycoprotein ligand-1. These multiple interactors play important roles in cell behaviour, and the roles of versican in modulating such processes are discussed.
基金partially by grants from the Research Grants Council of the Hong Kong SAR,China(Project No.SEG_CUHK02)
文摘Objective This study aims to explore the clinical applicability and relevance of giycosaminoglycan Chemical Exchange Saturation Transfer （gagCEST） for intervertebral disc. Methods 25 subjects ranging in age from 24 yrs to 74 yrs were enrolled, gagCEST was acquired using a single-slice TSE sequence on a 3T. Saturation used a continuous rectangular RF pulse with B1=0.8 I^T and a fixed duration time =1100 ms. Sagittal image was obtained firstly without saturation pulse, and then saturated images were acquired at 52 offsets ranging from ＋0.i25 to ＋_7 parts per million （ppm）. MR T2 relaxivity map was acquired at the identical location. Six subjects were scanned twice to assess scan-rescan reproducibility. Results GagCEST intraclass correlation coefficient （ICC） of six subjects was 0.759 for nucleus pulposus （NP） and 0.508 for annulus fibrosus （AF）. Bland-Altman plots showed NP had a mean difference of 0.10% （95% limits of agreement： -3.02% to 3.22%）; while that of AF was 0.34% （95% limits of agreement： -2.28% to 2.95%）. For the 25 subjects, gag CEST in NP decreased as disc degeneration increased, with a similar trend to T2 relaxivity. Gag CEST of AF showed a better correlation with disc degeneration than T2 relaxivity. Conclusion GagCEST in NP and AF decreased as disc degeneration increased, while gagCEST in AF showed a better correlation than T2 relaxivity.
基金Supported by Research Grants Council of the Hong Kong SAR,China,No.17111016 and No.17100819.
文摘Esophageal squamous cell carcinoma(ESCC)is a highly malignant disease that has a poor prognosis.Its high lethality is mainly due to the lack of symptoms at early stages,which culminates in diagnosis at a late stage when the tumor has already metastasized.Unfortunately,the common cancer biomarkers have low sensitivity and specificity in esophageal cancer.Therefore,a better understanding of the molecular mechanisms underlying ESCC progression is needed to identify novel diagnostic markers and therapeutic targets for intervention.The invasion of cancer cells into the surrounding tissue is a crucial step for metastasis.During metastasis,tumor cells can interact with extracellular components and secrete proteolytic enzymes to remodel the surrounding tumor microenvironment.Proteoglycans are one of the major components of extracellular matrix.They are involved in multiple processes of cancer cell invasion and metastasis by interacting with soluble bioactive molecules,surrounding matrix,cell surface receptors,and enzymes.Apart from having diverse functions in tumor cells and their surrounding microenvironment,proteoglycans also have diagnostic and prognostic significance in cancer patients.However,the functional significance and underlying mechanisms of proteoglycans in ESCC are not well understood.This review summarizes the proteoglycans that have been studied in ESCC in order to provide a comprehensive view of the role of proteoglycans in the progression of this cancer type.A long term goal would be to exploit these molecules to provide new strategies for therapeutic intervention.
基金Project partly supported by the Ph.D. Program of the National Edu-cational Committee (No. 2000044)the Chinese Medical Board(2003), China
文摘Objective: To identify the mutations of iduronate-2-sulfatase (IDS) gene, to reveal its mutation features, and to establish a basis for genetic counseling and prenatal gene diagnosis of Hunter syndrome. Methods: Urine glycosaminoglycans (GAGs) assay, PCR and DNA sequencing were performed to detect mutation of IDS gene of the patient and his parents. Results: The result showed that the patient was: DS(++), HS(++), KS(-), CS(-), and that both of his parents were negative. A frame-shift deletion mutation (1062 del 16) was identified in exon 7 of the patient's IDS gene. His parents' genotypes were normal. Conclusion:The patient's mutation was not inherited by his parents but a novel one. The mutation probably altered the primary structure and tertiary structure of IDS enzyme protein remarkably and lowered the activity of IDS enzyme greatly. Therefore it is supposed to be the direct cause of the disorder.
