Does epigenetics play a role in the pathology of osteoarthritis?

Idiopathic osteoarthritis (OA) is a complex, late-onset disease whose causes are still unknown. In spite of tremendous efforts, the search for the genes pre-disposing towards osteoarthritis has so far met with little success. We hypothesize that epigenetic changes play a major role in the pathology of OA. Epigenetics refers to stable, heritable, but potentially reversible modifications of gene expression that do not involve mutations in the DNA sequence, for example DNA methylation or histone modification. Epigenetic changes are gene and cell-type specific, may arise sporadically with increasing age or be provoked by environmental factors. To investigate whether epigenetic changes are significant factors in OA, we examined the DNA methylation status of the promoter regions of three genes that are expressed by OA, but not by normal, articular chondrocytes, namely MMP-3 (stromelysin-1), MMP-9 (gelatinase B) and MMP-13 (collagenase3). We hypothesized that these genes are silenced in normal chondrocytes by methylation of the cytosines of CpG dinucleotides in the respective promoter regions, but that abnormal expression is associated with a de-methylation, leading to eunsilencing f of gene expression. Cartilage was obtained from the femoral heads of 16 OA and 10 femoral neck fracture (#NOF) patients, which served as controls due to the inverse relationship between osteoporosis and OA. The cartilage was milled in a freezer mill with liquid nitrogen, DNA was extracted with a Qiagen kit, digested with methylation sensitive restriction enzymes, followed by PCR amplification. These enzymes will cut at their specific cleavage sites only if the CpGs is not methylated and thus allow us to determine methylation status of specific CpG sites.Results. Less than 5% of the chondrocytes in superficial layer from #NOF cartilage expressed degradative enzymes, whereas all cloned chondrocytes from advanced-stage OA cartilage were immunopositive. The overall % of CpG demethylation in the promoters of control patients (whose chondrocytes did not express the enzymes) was 20.1%, whereas 48.6% of CpG sites were demethylated in degradative chondrocytes of OA patients (p<0.001). For MMP-13, the increase in demethylation between control and OA was from 4 ..20%; for MMP-9 from 47 ..81% and for MMP-3 from 30 ..57%. However, not all available CpG sites were equally demethylated. Some sites were uniformly methylated in both OA and controls, others were demethylated even in controls. However, there was at least one crucial site for each degradative enzyme, where the differences in the degree of methylation were greatest and statistically different. These sites were at –110 for MMP-13; –36 for MMP-9; –635 for MMP-3. There was no relation between the % demethylation and the patient fs age and no apparent difference between males and females.Conclusions: We have demonstrated an association between abnormal gene expression of MMP-3, MMP-9 and MMP-13 and promoter DNA demethylation. This epigenetic dysregulation of genes appeared to be clonally inherited by daughter cells and may be typical for osteoarthritis and other complex, late-onset diseases.Correspondence should be addressed to Mr Carlos Wigderowitz, Honorary Secretary BORS, University Dept of Orthopaedic & Trauma Surgery, Ninewells Hospital & Medical School, Dundee DD1 9SY.None of the authors have received anything of value from a commercial or other party related directly or indirectly to the subject of the presentatio

Morphological, biochemical, and electrophysiological characterization of a clonal cell (H9c2) line from rat heart.

Morphological, electrophysiological, and biochemical properties of H9c2 cells, a permanent cell line derived from rat cardiac tissue, were studied. Although the lectin binding pattern revealed similar sugar residues in the surface coat ofH9c2 cells and isolated rat cardiocytes, heart-specific morphological structures could not be detected in H9c2 cells. Under physiological ionic conditions, H9c2 cells exhibited an outwardly rectifying, transient K ' current. When this current component was blocked by Ba2 ' and Cs+, we observed an inward current through Ca21 channels (15.8±2.2 pA/pF, n=18, measured as Ba21 current) that showed all characteristics of cardiac L-type currents. The activation kinetics were fast, and the current was stimulated by isoprotere-nol. The effect of isoproterenol was mimicked by forskolin or intracellularly applied cAMP. In radioligand binding experiments, we identified a specific, saturable, stereoselective and reversible high-affinity [3H]-(+)PN 200-110 binding with a dissociation constant Kd=0.53+0.28 nM and a maximal specific binding of Bm.=129.3+16.1 fmollmg protein. There was an additional low-affinity/high-capacity binding site, which is unlikely to be related to a Ca21 channel protein. Signal-transducing G proteins in membranes were characterized by [32P]ADP-ribosylation catalyzed by bacterial toxins and by the use of various antibodies. Cholera toxin substrates of 4

Japanese intellectual responses to China's rise

One of Japan’s leading daily newspapers, the Asahi Shimbun, carried an interview on December 12, 2012 with Dean of Tsinghua University’s Institute of Modern International Relations Yan Xuetong. In the course of that interview, Yan made a number of interesting observations. First, he made clear that he regarded Sino–American ‘conflict and rivalry’ as ‘inevitable’. Second, he suggested that the United States and China should ‘drop’ the idea of ‘mutual trust’, and that they should instead seek ‘cooperation without mutual trust’. Yan also seemed certain that China need not lose out to the United States in a competition for the world’s hearts-and-minds. Arguing that China’s ‘political morality’ is at a higher level than that of the West, Yan argued that the ancient Chinese emphasis on ‘fairness’ trumps ‘equality’; similarly, ‘civility’ surpasses ‘freedom’; and also, ‘justice’ is better than ‘democracy’

A systematic review of multidomain and lifestyle interventions to support the intrinsic capacity of the older population

Introduction: The focus on intrinsic capacity (IC) could help clinicians to design interventions to improve the health of the older population. This review aims to map the current state of the art in the field of multi-domain interventions based on the IC framework, to allow health professionals in identifying personalized clinical interventions, oriented to empower the older people with a holistic and positive approach. Methods: A systematic review of the literature was conducted in July 2021 analyzing manuscripts and articles of the last 10.5 years from PubMed, Scopus, Embase, Google Scholar and Elsevier databases. A total of 12 papers were included. Results: The majority of successful interventions are based on a goal setting approach where the older people are involved in the definition of the strategy to follow to remain active and independent. None of the study have used the IC as a framework to design a clinical intervention. Conclusion: To the best of our knowledge, no other reviews are reported in the literature regarding the IC. Our study offers several research directions, which may take the existing debates to the next level

WIND, GEOTAIL and GOES 9 observations of magnetic field dipolarization and bursty bulk flows in the near-tail

The WIND, GEOTAIL, and GOES 9 spacecraft were all in the nightside magnetosphere and Interball was in the solar wind when a substorm began at ∼07:25 UT on April 18, 1996. WIND and GEOTAIL were located at downstream distances of X=−12 to −14 Re. The separation between these spacecraft was ∼10 Re in the Y direction and less than ∼1 Re in Z. While the northward field component at GOES 9 began to increase immediately, little or no dipolarization was observed at WIND and GEOTAIL until a series of very rapid Bz increases were observed ∼25–30 min later. About ∼1–2 min prior to each dipolarization event at WIND and GEOTAIL an earthward flow burst with peak speeds of 100–500 km/s was initiated. The duration of these bursty bulk flows were 1–7 min. These unique observations are interpreted as strong evidence for the existence of spatially localized, but sometimes temporally overlapping flow bursts in the near‐tail during substorm expansion phase which result, cumulatively, in sufficient earthward magnetic flux transport to produce the well known dipolarization at geosynchronous orbit