Matrix-bound nanovesicle-associated IL-33 supports functional recovery after skeletal muscle injury by initiating a pro-regenerative macrophage phenotypic transition

Injuries to skeletal muscle are among the most common injuries in civilian and military populations, accounting for nearly 60% of extremity injuries. The standard of care for severe extremity injury has been focused upon limb salvage procedures and the utilization of tissue grafts or orthotics in conjunction with rehabilitation to avoid amputation. Nonetheless, many patients have persistent strength and functional deficits that permanently impact their quality of life. Preclinical and clinical studies have shown that partial restoration of functional skeletal muscle tissue following injury can be achieved by the implantation of a biologic scaffold composed of extracellular matrix (ECM). These favorable outcomes are mediated, at least in part, through local immunomodulation. The mechanisms underlying this immunomodulatory effect, however, are poorly understood. The present study investigates a potential mechanistic driver of the immunomodulatory effects; specifically, the effect of selected ECM components upon inflammation resolution and repair. Results show that the host response to skeletal muscle injury is profoundly altered and functional recovery decreased in il33-/- mice compared to age- and sex-matched wildtype counterparts by 14 days post-injury. Results also show that IL-33, contained within matrix-bound nanovesicles (MBV), supports skeletal muscle regeneration by regulating local macrophage activation toward a pro-remodeling phenotype via canonical and non-canonical pathways to improve functional recovery from injury compared to untreated il33-/- counterparts. Taken together, these data suggest that MBV and their associated IL-33 cargo represent a novel homeostatic signaling mechanism that contributes to skeletal muscle repair.

A bibliometric analysis of inflammation in sarcopenia from 2007 to 2022

OBJECTIVE

In recent years, the impact of inflammation regulation on the progression of sarcopenia has garnered significant attention in research. However, there has been a lack of bibliometric analysis on the literature pertaining to inflammation in sarcopenia. This study was designed for the purpose of exploring the current research trends in this field as well as general situations and hot spots through bibliometric analysis.

METHODS

Searches were performed on the Web of Science Core Collection for articles related to inflammation in sarcopenia from 2007 to 2022, and selected in compliance with PRISMA guidelines. A variety of data were analyzed and visualized using VOSviewer and CiteSpace, including countries, institutions, authors, keywords, journals, and publications.

RESULTS

1833 articles were obtained in the last 16 years in all. The number of publications and citations increased from 2007 to 2022, with a notable rise occurring after 2016. Based on the results, the United States, the University of Melbourne, Nutrients, and Marzetti Emanuele were the most productive countries, institutions, journals, and authors, respectively. The primary keywords were oxidative stress and insulin resistance, and the burst detection analysis of keywords found that there is a possibility that future research will focus on "Inflammatory Bowel Disease".

CONCLUSION

This is the first bibliometric analysis of inflammation in sarcopenia. The interaction between oxidative stress, insulin resistance and inflammation in sarcopenia is regarded as the current research priorities. As sarcopenia becomes more prevalent, a focus will be placed on determining the molecular mechanisms and therapeutic targets for regulating inflammation to intervene in sarcopenia.

Overall Rebalancing of Gut Microbiota Is Key to Autism Intervention

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with unclear etiology, and due to the lack of effective treatment, ASD patients bring enormous economic and psychological burden to families and society. In recent years, many studies have found that children with ASD are associated with gastrointestinal diseases, and the composition of intestinal microbiota (GM) is different from that of typical developing children. Thus, many researchers believe that the gut-brain axis may play an important role in the occurrence and development of ASD. Indeed, some clinical trials and animal studies have reported changes in neurological function, behavior, and comorbid symptoms of autistic children after rebalancing the composition of the GM through the use of antibiotics, prebiotics, and probiotics or microbiota transfer therapy (MMT). In view of the emergence of new therapies based on the modulation of GM, characterizing the individual gut bacterial profile evaluating the effectiveness of intervention therapies could help provide a better quality of life for subjects with ASD. This article reviews current studies on interventions to rebalance the GM in children with ASD. The results showed that Lactobacillus plantarum may be an effective strain for the probiotic treatment of ASD. However, the greater effectiveness of MMT treatment suggests that it may be more important to pay attention to the overall balance of the patient's GM. Based on these findings, a more thorough assessment of the GM is expected to contribute to personalized microbial intervention, which can be used as a supplementary treatment for ASD.

IL-1β induces changes in expression of core circadian clock components PER2 and BMAL1 in primary human chondrocytes through the NMDA receptor/CREB and NF-κB signalling pathways

The circadian clock is a specialised cell signalling circuit present in almost all cells. It controls the timing of key cell activities such as proliferation and differentiation. In osteoarthritis, expression of two components of the circadian clock, BMAL1 and PER2 is altered in chondrocytes and this change has been causally linked with the increase in proliferation and altered chondrocyte differentiation in disease. IL-1β, an inflammatory cytokine abundant in OA joints, has previously been shown to induce changes in BMAL1 and PER2 expression in chondrocytes. The purpose of this study is to identify the mechanism involved. We found IL-1β treatment of primary human chondrocytes led to activation of NMDA receptors as evidenced by an increase in phosphorylation of GluN1 and an increase in intracellular calcium which was blocked by the NMDAR antagonist MK801. Levels of phosphorylated CREB were also elevated in IL-1β treated cells and this effect was blocked by co-treatment of cells with IL-1β and the NMDAR antagonist MK-801. Knockdown of CREB or inhibition of CREB activity prevented the IL-1β induced increase in PER2 expression in chondrocytes but had no effect on BMAL1. Phosphorylated p65 levels were elevated in IL-1β treated chondrocytes indicating increased NF-κB activation. Inhibition of NF-κB activity prevented the IL-1β induced reduction in BMAL1 expression and partially mitigated the IL-1β induced increase in PER2 expression in chondrocytes. These data indicate that the NMDAR/CREB and NF-κB signalling pathways regulate the core circadian clock components PER2 and BMAL1 in chondrocytes. Given that changes in expression of these clock components have been observed in a wide range of diseases, these findings may be broadly relevant for understanding the mechanism leading to circadian clock changes in pathology.

Altered N-methyl D-aspartate receptor subunit expression causes changes to the circadian clock and cell phenotype in osteoarthritic chondrocytes

The chondrocyte circadian clock is altered in osteoarthritis. This change is implicated in the disease-associated changes in chondrocyte phenotype and cartilage loss. Why the clock is changed is unknown. N-methyl-D-aspartate receptors (NMDAR) are critical for regulating the hypothalamic clock. Chondrocytes also express NMDAR and the type of NMDAR subunits expressed changes in osteoarthritis.

OBJECTIVE

To determine if NMDAR regulate the chondrocyte clock and phenotype.

DESIGN

Chondrocytes isolated from macroscopically-normal (MN) and osteoarthritic human cartilage were treated with NMDAR antagonists or transfected with GRIN2A or GRIN2B-targetting siRNA. H5 chondrocytes were transfected with GluN2B-expression plasmids. Clock genes and chondrocyte phenotypic markers were measured by RT-qPCR.

RESULTS

PER2 amplitude was higher and BMAL1 amplitude lower in osteoarthritic compared to MN chondrocytes. In osteoarthritic chondrocytes, NMDAR inhibition restored PER2 and BMAL1 expression to levels similar to MN chondrocytes, and resulted in reduced MMP13 and COL10A1. Paradoxically, NMDAR inhibition in MN chondrocytes resulted in increased PER2, decreased BMAL1 and increased MMP13 and COL10A1. Osteoarthritic, but not MN chondrocytes expressed GluN2B NMDAR subunits. GluN2B knockdown in osteoarthritic chondrocytes restored expression of circadian clock components and phenotypic markers to levels similar to MN chondrocytes. Ectopic expression of GluN2B resulted in reduced BMAL1, increased PER2 and altered SOX9, RUNX2 and MMP13 expression. Knockdown of PER2 mitigated the effects of GluN2B on SOX9 and MMP13.

CONCLUSIONS

NMDAR regulate the chondrocyte clock and phenotype suggesting NMDAR may also regulate clocks in other peripheral tissues. GluN2B expression in osteoarthritis may contribute to pathology by altering the chondrocyte clock.

Obesity, osteoarthritis and genetic risk: The rs182052 polymorphism in the ADIPOQ gene is potentially associated with risk of knee osteoarthritis

Objectives

Given the function of adiponectin (ADIPOQ) on the inflammatory condition of obesity and osteoarthritis (OA), we hypothesized that the ADIPOQ gene might be a candidate gene for a marker of susceptibility to OA.

Methods

We systematically screened three tagging polymorphisms (rs182052, rs2082940 and rs6773957) in the ADIPOQ gene, and evaluated the association between the genetic variants and OA risk in a case-controlled study that included 196 OA patients and 442 controls in a northern Chinese population. Genotyping was performed using the Sequenom MassARRAY iPLEX platform.

Results

The single nucleotide polymorphism (SNP) rs182052 was found to be potentially associated with knee OA risk (additive model: odds ratio = 1.38; 95% confidence interval 1.07 to 1.76; p = 0.012). Furthermore, a non-significant association was observed for rs182052 and body mass index with regard to OA risk in interaction analyses (p = 0.063). Similarly, no significant interaction was detected for rs182052 and age with regard to OA risk (p = 0.614).

Conclusion

These findings suggest that the SNP rs182052 in the ADIPOQ gene may potentially modify individual susceptibility to knee OA in the Chinese population. Further studies are warranted to investigate our findings in more depth.

Cite this article: L. Jiang, X. Zhu, J. Rong, B. Xing, S. Wang, A. Liu, M. Chu, G. Huang. Obesity, osteoarthritis and genetic risk: The rs182052 polymorphism in the ADIPOQ gene is potentially associated with risk of knee osteoarthritis. Bone Joint Res 2018;7:494–500. DOI: 10.1302/2046-3758.77.BJR-2017-0274.R1.

Skin resistance to UVB-induced oxidative stress and hyperpigmentation by the topical use of Lactobacillus helveticus NS8-fermented milk supernatant

AIMS

In this study, we investigated the preventive properties of the supernatant of Lactobacillus helveticus NS8-fermented milk (NS8-FS) against UV light-induced skin oxidative damage and hyperpigmentation.

METHODS AND RESULTS

NS8-FS exhibited significant radical scavenging activity in tests with ABST⁺ and DPPH scavenging methods, and as well strongly inhibited 3-morpholinosydnonimine (Sin-1)-induced ROS generation in HaCat keratinocytes. Unexpectedly, NS8-FS was found to inhibit melanin production in B16F10 melanoma cells and to exhibit inhibitory effects both to the enzymatic activity of tyrosinase (TYR) and the expression of proteins required for melanin synthesis. In SKH-1 hairless mice, topical application of NS8-FS alleviated UVB-induced skin photodamage, including the improvement of the appearance of epidermal thickness, transepidennal water loss and lipid peroxidation levels. In the tanning guinea pig model, the whitening effect of NS8-FS was demonstrated using Masson-Fontana staining and TYR staining. Furthermore, NS8-FS was shown to stimulate the nuclear translocation and activation of the Nrf2 protein, along with recovery of antioxidant enzyme activities.

CONCLUSION

NS8-FS exhibits the protective capacities against UV light-induced skin oxidative damage and hyperpigmentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our findings indicate the potential of cell-free fermented products of lactic acid bacteria in topical photoprotection.

The rs4238326 polymorphism in ALDH1A2 gene potentially associated with non-post traumatic knee osteoarthritis susceptibility: a two-stage population-based study

OBJECTIVE

A recent genome-wide association study reported significant associations of genetic variants within the ALDH1A2 gene with osteoarthritis (OA) of the hand in European populations. However, these findings have not been well generalized to other joints, or to other populations.

METHODS

We performed a two-stage population-based case-control study including 196 non-post traumatic knee OA cases and 442 controls in the first stage and independent 143 non-post traumatic knee OA cases and 238 controls in the second stage in a Chinese population by genotyping eight tagging polymorphisms in ALDH1A2.

RESULTS

In the first stage, the single nucleotide polymorphism (SNP) rs4238326 was found to be potentially associated with knee OA risk (additive model: odds ratio [OR] = 0.70; 95% confidence interval [95% CI] = 0.49-1.01; P = 0.055), which was further confirmed in the second stage with similar effect (additive model: OR = 0.60; 95% CI = 0.38-0.95; P = 0.029). After combining the two stages, we found that the variant C allele of rs4238326 was probably associated with decreased risk of knee OA (additive model: OR = 0.65; 95% CI = 0.49-0.86; P = 0.003). Furthermore, interaction analyses showed that rs4238326 interacted multiplicatively with age to contribute to knee OA risk (interaction P = 0.041).

CONCLUSIONS

These findings indicate that the SNP rs4238326 in ALDH1A2 gene may potentially modify individual susceptibility to knee OA in the Chinese population. Beyond that, further studies are warranted to validate and extend our findings, and future functional studies are required to clarify the possible mechanisms.

Clinical interrogation and application of super-selective intracranial artery infusion chemotherapy for lung cancer patients with brain metastases

OBJECTIVE

The purpose of this study was to evaluate the clinical efficacy of super-selective intracranial artery infusion chemotherapy and to determine correlated prognostic parameters for advanced lung cancer patients with brain metastases.

PATIENTS AND METHODS

Fifty-four lung cancer patients with brain metastasis who had no previous treatment were enrolled for the study. These patients received super-selective intracranial artery infusion chemotherapy, as well as arterial infusion chemotherapy for primary and metastatic lesions. The procedure was performed once every 4 weeks. Patients were monitored to evaluate short-term clinical outcomes 4 weeks after the first 2 treatments, and follow-up visits performed every 4 weeks after the first 4 treatments until the appearance of disease progression or intolerable toxicity.

RESULTS

All 54 cases were treated at least 4 times. The overall response rate was 55.56% (30/54), and the disease control rate was 85.19% (46/54). The median overall survival was 7 months, with a 95% confidence interval (CI) of 5.87-8.13 months, and the median progression-free survival was 4 months, with a 95% CI of 3.20-4.80 months. The 6-month survival rate and 1-year survival rate were 81.48% (44/54) and 18.52% (10/54), respectively.

CONCLUSION

Super-selective intracranial artery infusion chemotherapy provides a clinically efficacious avenue of treatment for lung cancer patients with brain metastases. Pathological classification, Karnofsky performance status, and extracranial metastases may serve as reliable prognostic parameters in determining the clinical outcomes for lung cancer patients with brain metastases.

No association of the single nucleotide polymorphism rs8044769 in the fat mass and obesity-associated gene with knee osteoarthritis risk and body mass index: A population-based study in China

OBJECTIVES

Previous genome-wide association studies (GWAS) have reported significant association of the single nucleotide polymorphism (SNP) rs8044769 in the fat mass and obesity-associated gene (FTO) with osteoarthritis (OA) risk in European populations. However, these findings have not been confirmed in Chinese populations.

METHODS

We systematically genotyped rs8044769 and evaluated the association between the genetic variants and OA risk in a case-controlled study including 196 OA cases and 442 controls in a northern Chinese population. Genotyping was performed using the Sequenom MassARRAY iPLEX platform.

RESULTS

We found that the variant T allele of rs8044769 showed no significant association of OA risk (p = 0.791), or association with body mass index (BMI) (pmeta = 0.786) in an additive genetic model. However, we detected a significant interaction between rs8044769 genotypes and BMI on OA risk (p = 0.037), as well as a borderline interaction between rs8044769 genotypes and age on OA risk (p = 0.062).

CONCLUSIONS

Our findings indicate that rs8044769 in the FTO gene may not modify individual susceptibility to OA or increased BMI in the Chinese population. Further studies are warranted to validate and extend our findings.Cite this article: Prof L. Jiang. No association of the single nucleotide polymorphism rs8044769 in the fat mass and obesity-associated gene with knee osteoarthritis risk and body mass index: A population-based study in China. Bone Joint Res 2016;5:169-174. DOI: 10.1302/2046-3758.55.2000589.

Natural antisense RNAs are involved in the regulation of CD45 expression in autoimmune diseases

CD45 is a transmembrane protein tyrosine phosphatase that is specifically expressed in hematopoietic cells and can initiate signal transduction via the dephosphorylation of tyrosine. Alternatively spliced transcript variants of this gene encode distinct isoforms, which indicate different functional states of CD45. Among these variants, CD45RO, which contains neither exon 4, 5, or 6, is over-expressed in lymphocytes in autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and type I diabetes. The CD45 RO serves as a marker of the immune response activity and lymphocyte development. Previous studies have indicated that exon splicing is generally correlated with local hypermethylated DNA and acetylated histone modification, while autoimmune diseases are commonly associated with global hypomethylation and histone deacetylation in lymphocytes. Thus, the question arises of how exons 4, 5, and 6 of CD45RO are excluded under the status of global DNA hypomethylation and histone deacetylation in these autoimmune diseases. On the basis of the analyses of the context sequence of CD45 and its natural antisense RNA in GenBank, we proposed that the long noncoding RNA encoded by the natural antisense gene of CD45 contributes to the expressional regulation of the CD45RO splicing variant via recruitment of DNA methyltransferase and histone modification modulators specific to the sense gene CD45; thus, it is associated with the over-expression of CD45RO and the functional regulation of lymphocytes in the pathogenic development of autoimmune diseases.

Gene expression of the p16(INK4a)-Rb and p19(Arf)-p53-p21(Cip/Waf1) signaling pathways in the regulation of hematopoietic stem cell aging by ginsenoside Rg1

The elucidation of the molecular mechanisms underlying the effects of traditional Chinese medicines in clinical practice is a key step toward their worldwide application, and this topic is currently a subject of intense research interest. Rg1, a component of ginsenoside, has recently been shown to perform several pharmacological functions; however, the underlying mechanisms of these effects remain unclear. In the present study, we investigated whether Rg1 has an anti-senescence effect on hematopoietic stem cells (HSCs) and the possible molecular mechanisms driving any effects. The results showed that Rg1 could effectively delay tert-butyl hydroperoxide (t-BHP)-induced senescence and inhibit gene expression in the p16(INK4a)-Rb and p19(Arf)-p53-p21(Cip/Waf1) signaling pathways in HSCs. Our study suggested that these two signaling pathways might be potential targets for elucidating the molecular mechanisms of the Rg1 anti-senescence effect.

Epidemiological comparison of clinical manifestations according to HLA-B*27 carrier status of Chinese ankylosing spondylitis patients

The aim of the study was to investigate and compare the clinical manifestations between HLA-B27(+) and HLA-B27(-) ankylosing spondylitis (AS) patients in order to obtain knowledge of the impact of HLA-B27 status on AS, and to inform clinical treatment. A nationwide epidemiological investigation was performed from November 2008 to October 2010. The demographic data and clinical characteristics, and the status of HLA-B27 were collected using questionnaires and laboratory assay, respectively. A total of 2144 patients (78.5% males and 78.4% HLA-B27(+) AS patients) participated in this study. The percentages of males, patients with family history, and involvement of lumbar spine, thoracic spine and hip joints, were observed to be significantly higher in the HLA-B27(+) AS patients than in their HLA-B27(-) AS peers.

Synthesis of new derivatives of copper complexes of Josiphos family ligands for applications in asymmetric catalysis

New derivatives of copper complexes of Josiphos family ligands have been prepared and studied in asymmetric catalytic addition of Grignard reagents to enones, enoates and aromatic ketones.

Review of porous silicon preparation and its application for lithium-ion battery anodes

Silicon is of great interest for use as the anode material in lithium-ion batteries due to its high capacity. However, certain properties of silicon, such as a large volume expansion during the lithiation process and the low diffusion rate of lithium in silicon, result in fast capacity degradation in limited charge/discharge cycles, especially at high current rate. Therefore, the use of silicon in real battery applications is limited. The idea of using porous silicon, to a large extent, addresses the above-mentioned issues simultaneously. In this review, we discuss the merits of using porous silicon for anodes through both theoretical and experimental study. Recent progress in the preparation of porous silicon through the template-assisted approach and the non-template approach have been highlighted. The battery performance in terms of capacity and cyclability of each structure is evaluated.

SU-E-I-06: Measurement of Skin Dose from Dental Cone-Beam CT Scans

PURPOSE

To directly measure skin dose using point-dosimeters from dental cone-beam CT (CBCT) scans. To compare the results among three different dental CBCT scanners and compare the CBCT results with those from a conventional panoramic and cephalomic dental imaging system.

METHODS

A head anthropomorphic phantom was used with nanoDOT dosimeters attached to specified anatomic landmarks of selected radiosensitive tissues of interest. To ensure reliable measurement results, three dosimeters were used for each location. The phantom was scanned under various modes of operation and scan protocols for typical dental exams on three dental CBCT systems plus a conventional dental imaging system. The Landauer OSL nanoDOT dosimeters were calibrated under the same imaging condition as the head phantom scan protocols, and specifically for each of the imaging systems. Using nanoDOT dosimeters, skin doses at several positions on the surface of an adult head anthropomorphic phantom were measured for clinical dental imaging.

RESULTS

The measured skin doses ranged from 0.04 to 4.62mGy depending on dosimeter positions and imaging systems. The highest dose location was at the parotid surface for all three CBCT scanners. The surface doses to the locations of the eyes were ∼4.0mGy, well below the 500mGy threshold for possibly causing cataract development. The results depend on x-ray tube output (kVp and mAs) and also are sensitive to SFOV. Comparing to the conventional dental imaging system operated in panoramic and cephalometric modes, doses from all three CBCT systems were at least an order of magnitude higher. No image artifact was caused by presence of nanoDOT dosimeters in the head phantom images.

CONCLUSIONS

Direct measurements of skin dose using nanoDOT dosimeters provided accurate skin dose values without any image artifacts. The results of skin dose measurements serve as dose references in guiding future dose optimization efforts in dental CBCT imaging.

Metabolic fingerprinting reveals differences between shoots of wild and cultivated carrot (Daucus carota L.) and suggests maternal inheritance or wild trait dominance in hybrids

Differences between the metabolic content of cultivars and their related wild species not only have implications for breeding and food quality, but also for the increasingly studied area of crop to wild introgression. Wild and cultivated western carrots belong to the same outcrossing species and hybridize under natural conditions. The metabolic fingerprinting of Dutch wild carrot and of western orange carrot cultivar shoots using (1)H NMR showed only quantitative differences in chemical content, indicating relatively low divergence after domestication. Main differences reside in the primary metabolite content and in the concentrations of chlorogenic acid and feruloyl quinic acid in the shoots of the different carrot types. Wild×cultivar hybrids cannot be distinguished from wild plants based on the metabolome, suggesting maternal, maternal environment, or dominance effects, and indicating high hybrid fitness in wild conditions. Considering these similarities, introgression is a real possibility in carrots, but understanding its consequences would require further studies using backcrosses in a multiple environments.

The impact of HIV/HCV co-infection on health care utilization and disability: results of the ACTG Longitudinal Linked Randomized Trials (ALLRT) Cohort

HIV/hepatitis C virus (HCV) co-infection places a growing burden on the HIV/AIDS care delivery system. Evidence-based estimates of health services utilization among HIV/HCV co-infected patients can inform efficient planning. We analyzed data from the ACTG Longitudinal Linked Randomized Trials (ALLRT) cohort to estimate resource utilization and disability among HIV/HCV co-infected patients and compare them to rates seen in HIV mono-infected patients. The analysis included HIV-infected subjects enrolled in the ALLRT cohort between 2000 and 2007 who had at least one CD4 count measured and completed at least one resource utilization data collection form (N = 3143). Primary outcomes included the relative risk of hospital nights, emergency department (ED) visits, and disability days for HIV/HCV co-infected vs HIV mono-infected subjects. When controlling for age, sex, race, history of AIDS-defining events, current CD4 count and current HIV RNA, the relative risk of hospitalization, ED visits, and disability days for subjects with HIV/HCV co-infection compared to those with HIV mono-infection were 1.8 (95% CI: 1.3-2.5), 1.7 (95% CI: 1.4-2.1), and 1.6 (95% CI: 1.3-1.9) respectively. Programs serving HIV/HCV co-infected patients can expect approximately 70% higher rates of utilization than expected from a similar cohort of HIV mono-infected patients.

Clinical and genetic correlates of soluble P-selectin in the community

BACKGROUND

P-selectin is a cell adhesion molecule that is involved in atherogenesis, and soluble concentrations of this biomarker reflect cardiovascular risk. However, the clinical correlates and genetic characterization of soluble P-selectin have not been clearly elucidated.

OBJECTIVE

To describe clinical and genetic correlates of circulating P-selectin in the community.

METHODS

In Framingham Heart Study Offspring (European descent) and Omni (ethnic/racial minority) participants, we examined the association of cardiovascular risk factors with soluble P-selectin concentrations. In Offspring participants, we evaluated heritability, linkage and association of 29 SELP single-nucleotide polymorphisms (SNPs) with adjusted P-selectin concentrations.

RESULTS

In multivariable analysis of 3,690 participants (54% women, mean age 60 +/- 10 years), higher log-transformed P-selectin concentrations were inversely associated with female sex and hormone replacement therapy, and positively associated with age, ethnic/racial minority status, cigarette smoking, waist circumference, systolic blood pressure, fasting glucose, and total/high-density lipoprotein cholesterol and triglyceride concentrations. Clinical factors explained 10.4% of the interindividual variability in P-selectin concentrations. In 571 extended pedigrees (n = 1,841) with >or= 2 phenotyped members per family, multivariable-adjusted heritability was 45.4 +/- 5.8%. Among the SELP SNPs examined, a non-synonymous SNP (rs6136) encoding a threonine-to-proline substitution at position 715 was highly significantly associated with decreased P-selectin concentrations (P = 5.2 x 10(-39)), explaining 9.7% of variation after adjustment for clinical factors.

CONCLUSIONS

Multiple clinical factors and an SNP in the SELP gene were significantly associated with circulating P-selectin concentrations. One SNP in SELP explained significant variation in circulating P-selectin concentrations, even after accounting for known clinical correlates.

Monte Carlo simulation of release of vesicular content in neuroendocrine cells

The release of transmitter from the vesicle, its diffusion through the fusion pore, and the cleft and its interaction with the carbon electrode were simulated using the Monte Carlo method. According to the simulation the transmitter release is largely determined by geometric factors--the ratio of the fusion pore cross-sectional and vesicular areas, if the diffusion constant is as in the aqueous solution--but the speed of transmitter dissociation from the gel matrix plays an important role during the rise phase of release. Transmitter is not depleted near the entrance to the fusion pore and there is no cleft-to-vesicle feedback, but the depletion becomes evident if the diffusion constant is reduced, especially if the pore is wide. In general, the time course of amperometric currents closely resembles the time course of the simulated transmitter concentration in the cleft and the time course of release. Surprisingly, even a tenfold change of the electrode efficiency has only a marginal effect on the amplitude or the time course of amperometric currents. Greater electrode efficiency however lowers the cleft concentration, but only if the cleft is narrow. As the cleft widens the current amplitudes diminish and rise times lengthen, but the decay times are less affected. Moreover, the amplitude dependence of the rise and decay times becomes steeper as the cleft widens and/or as the release kinetics slows. Finally, lower diffusion constant of transmitter in the narrow cleft does not further prolong the amperometric currents, whose slow time course reflects slow release kinetics.

Substrate specificity of the heparan sulfate hexuronic acid 2-O-sulfotransferase

The interaction of heparan sulfate with different ligand proteins depends on the precise location of O-sulfate groups in the polysaccharide chain. We have previously shown that overexpression in human kidney 293 cells of a mouse mastocytoma 2-O-sulfotransferase (2-OST), previously thought to catalyze the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to C2 of L-iduronyl residues, preferentially increases the level of 2-O-sulfation of D-glucuronyl units [Rong, J., Habuchi, H., Kimata, K., Lindahl, U., and Kusche-Gullberg, M. (2000) Biochem. J. 346, 463-468]. In the study presented here, we further investigated the substrate specificity of the mouse mastocytoma 2-OST. Different polysaccharide acceptor substrates were incubated with cell extracts from 2-OST-transfected 293 cells together with the sulfate donor 3'-phosphoadenosine 5'-phospho[(35)S]sulfate. Incubations with O-desulfated heparin, predominantly composed of [(4)alphaIdoA(1)-(4)alphaGlcNSO(3)(1)-](n)(), resulted in 2-O-sulfation of iduronic acid. When, on the other hand, an N-sulfated capsular polysaccharide from Escherichia coli K5, with the structure [(4)betaGlcA(1)-(4)alphaGlcNSO(3)(1)-](n)(), was used as an acceptor, sulfate was transferred almost exclusively to C2 of glucuronic acid. Substrates containing both iduronic and glucuronic acid residues in about equal proportions strongly favored sulfation of iduronic acid. In agreement with these results, the 2-OST was found to have a approximately 5-fold higher affinity for iduronic acid-containing substrate disaccharide units (K(m) approximately 3.7 microM) than for glucuronic acid-containing substrate disaccharide units (K(m) approximately 19.3 microM).

Advanced glycosylation end products, protein kinase C and renal alterations in diabetic rats

OBJECTIVE

To study the relationship between advanced glycosylation end products (AGE) and protein kinase C (PKC), and their effects on renal alteration in diabetic rats.

METHODS

Insulin or aminoguanidine was administered to diabetic rats. Blood glucose, hemoglobin A1c (HbA1c), glomerular tissue extracts AGE (GTE-AGE), PKC, glomerular basement membrane thickness (GBMT) and urine protein/creatinine (Pr/Cr) ratio in diabetic rats were measured and analysed.

RESULTS

Levels of blood glucose, HbA1c and AGE, PKC activity, the Pr/Cr ratio and GBMT were all significantly increased (P values all less than 0.01) in diabetic rats. Insulin could decrease the formation of HbA1c and AGE, and improve PKC activity. Aminoguanidine had no influence on PKC activity (P > 0.05) although it decreased the formation of AGE. Both drugs could delay the increase of urine Pr/Cr ratio and GBMT (P < 0.05 or P < 0.01).

CONCLUSIONS

Chronic hyperglycemia may lead to an increase of PKC activity. HbA1c and AGE may not directly contribute to alterations of PKC activity, but the increase of PKC activity could promote the action of AGE on GBM thickening. It is important to inhibit the formation of AGE and reduce the PKC activity so as to prevent or delay the development of diabetic nephropathy.

Expression of heparan sulphate L-iduronyl 2-O-sulphotransferase in human kidney 293 cells results in increased D-glucuronyl 2-O-sulphation

Functionally important interactions between heparan sulphate and a variety of proteins depend on the precise location of O-sulphate groups. Such residues occur at C-2 of L-iduronic (IdoA) and D-glucuronic acid (GlcA) units, and at C-3 and C-6 of D-glucosamine (GlcN) units. Stable transfection of human embryonic kidney 293 cells with a cDNA encoding mouse mastocytoma IdoA 2-O-sulphotransferase resulted in an approx. 6-fold increase in O-sulphotransferase activity, compared with control cells, as determined using O-desulphated heparin as an acceptor. Structural analysis of endogenous heparan sulphate in the transfected cells, following metabolic labelling with either [(3)H]GlcN or [(35)S]sulphate, showed appreciable formation of -GlcA(2-OSO(3))-GlcNSO(3)- disaccharide units (6% of total disaccharide units; 17% of total O-sulphated disaccharide units) that were essentially absent from heparan sulphate from control cells. The increase in GlcA 2-O-sulphation was accompanied by a decrease in the amount of IdoA formed, whereas overall 2-O-sulphation or 6-O-sulphation remained largely unaffected. These findings indicate that 2-O-sulphation of IdoA and GlcA residues is catalysed by the same enzyme in heparan sulphate biosynthesis.

A novel strategy to generate biologically active neo-glycosaminoglycan conjugates

Heparin and heparan sulfate are structurally related polysaccharides with a variety of biological effects/functions. Most of these effects are due to interactions, of varying specificity, between the negatively charged polysaccharide chains and proteins. While such interactions generally involve a single saccharide domain of decasaccharide size or less, ternary complexes of two protein molecules binding to separate domains on a single polysaccharide chain are known to occur. To facilitate studies on domain organization and its importance for biological function a strategy was developed to chemically conjugate defined heparin oligomers in linear and chemoselective fashion. The procedure requires that the oligosaccharide to provide the reducing-terminal domain of the conjugate is generated by lyase degradation of a parent polysaccharide, whereas the nonreducing-terminal domain is obtained through deaminative cleavage with nitrous acid. The applicability of the method was demonstrated by constructing a conjugate composed of two heparin 12-mers, of which the reducing-terminal component contained the antithrombin-binding region, whereas the nonreducing-terminal domain did not. Contrary to any of the unconjugated oligomers, the product was found to efficiently promote the inactivation of thrombin by antithrombin.

Optimization of nutrition: polyphenols and vascular protection

The role of polyphenols in human nutrition is discussed on the basis of their redox chemistry, which accounts for the observed antioxidant effect and in turn for their protective effect against atherosclerosis. Epidemiologic data, together with experimental pathology and cell biology, support the recommendation that optimal nutrition should contain polyphenols in amounts that may be better described as a "Recommended Optimal Intake" (ROI) than as a "Recommended Dietary Allowance" (RDA). Because a valid procedure to identify polyphenols in plasma is not available, analysis of plasma antioxidant capacity is instead suggested as a suitable index to define the optimal nutritional intake.

Differential effect of shear stress on extracellular signal-regulated kinase and N-terminal Jun kinase in endothelial cells. Gi2- and Gbeta/gamma-dependent signaling pathways

Shear stress differentially regulates production of many vasoactive factors at the level of gene expression in endothelial cells that may be mediated by mitogen-activated protein kinases, including extracellular signal-regulated kinase (ERK) and N-terminal Jun kinase (JNK). Here we show, using bovine aortic endothelial cells (BAEC), that shear stress differentially regulates ERK and JNK by mechanisms involving Gi2 and pertussis toxin (PTx)-insensitive G-protein-dependent pathways, respectively. Shear activated ERK with a rapid, biphasic time course (maximum by 5 min and basal by 30-min shear exposure) and force dependence (minimum and maximum at 1 and 10 dyn/cm2 shear stress, respectively). PTx treatment prevented shear-dependent activation of ERK1/2, consistent with a Gi-dependent mechanism. In contrast, JNK activity was maximally turned on by a threshold level of shear force (0.5 dyn/cm2 or higher) with a much slower and prolonged time course (requiring at least 30 min to 4 h) than that of ERK. Also, PTx had no effect on shear-dependent activation of JNK. To further define the shear-sensitive ERK and JNK pathways, vectors expressing hemagglutinin epitope-tagged ERK (HA-ERK) or HA-JNK were co-transfected with other vectors by using adenovirus-polylysine in BAEC. Expression of the mutant (alpha)i2(G203), antisense G(alpha)i2 and a dominant negative Ras (N17Ras) prevented shear-dependent activation of HA-ERK, while that of (alpha)i2(G204) and antisense (alpha)i3 did not. Expression of a Gbeta/gamma scavenger, the carboxyl terminus of beta-adrenergic receptor kinase (betaARK-ct), and N17Ras inhibited shear-dependent activation of HA-JNK. Treatment of BAEC with genistein prevented shear-dependent activation of ERK and JNK, indicating the essential role of tyrosine kinase(s) in both ERK and JNK pathways. These results provide evidence that 1) Gi2-protein, Ras, and tyrosine kinase(s) are upstream regulators of shear-dependent activation of ERK and 2) that shear-dependent activation of JNK is regulated by mechanisms involving Gbeta/gamma, Ras, and tyrosine kinase(s).