Microarray gene expression profiling of osteoarthritic bone suggests altered bone remodelling, WNT and transforming growth factor-β/bone morphogenic protein signalling

Osteoarthritis (OA) is characterized by alterations to subchondral bone as well as articular cartilage. Changes to bone in OA have also been identified at sites distal to the affected joint, which include increased bone volume fraction and reduced bone mineralization. Altered bone remodelling has been proposed to underlie these bone changes in OA. To investigate the molecular basis for these changes, we performed microarray gene expression profiling of bone obtained at autopsy from individuals with no evidence of joint disease (control) and from individuals undergoing joint replacement surgery for either degenerative hip OA, or fractured neck of femur (osteoporosis [OP]). The OP sample set was included because an inverse association, with respect to bone density, has been observed between OA and the low bone density disease OP. Compugen human 19K-oligo microarray slides were used to compare the gene expression profiles of OA, control and OP bone samples. Four sets of samples were analyzed, comprising 10 OA-control female, 10 OA-control male, 10 OA-OP female and 9 OP-control female sample pairs. Print tip Lowess normalization and Bayesian statistical analyses were carried out using linear models for microarray analysis, which identified 150 differentially expressed genes in OA bone with t scores above 4. Twenty-five of these genes were then confirmed to be differentially expressed (P < 0.01) by real-time PCR analysis. A substantial number of the top-ranking differentially expressed genes identified in OA bone are known to play roles in osteoblasts, osteocytes and osteoclasts. Many of these genes are targets of either the WNT (wingless MMTV integration) signalling pathway (TWIST1, IBSP, S100A4, MMP25, RUNX2 and CD14) or the transforming growth factor (TGF)-β/bone morphogenic protein (BMP) signalling pathway (ADAMTS4, ADM, MEPE, GADD45B, COL4A1 and FST). Other differentially expressed genes included WNT (WNT5B, NHERF1, CTNNB1 and PTEN) and TGF-β/BMP (TGFB1, SMAD3, BMP5 and INHBA) signalling pathway component or modulating genes. In addition a subset of genes involved in osteoclast function (GSN, PTK9, VCAM1, ITGB2, ANXA2, GRN, PDE4A and FOXP1) was identified as being differentially expressed in OA bone between females and males. Altered expression of these sets of genes suggests altered bone remodelling and may in part explain the sex disparity observed in OA

MID1 and MID2 homo- and heterodimerise to tether the rapamycin-sensitive PP2A regulatory subunit, Alpha 4, to microtubules: implications for the clinical variability of X-linked Opitz GBBB syndrome and other developmental disorders

BACKGROUND: Patients with Opitz GBBB syndrome present with a variable array of developmental defects including craniofacial, cardiac, and genital anomalies. Mutations in the X-linked MID1 gene, which encodes a microtubule-binding protein, have been found in ~50% of Opitz GBBB syndrome patients consistent with the genetically heterogeneous nature of the disorder. A protein highly related to MID1, called MID2, has also been described that similarly associates with microtubules. RESULTS: To identify protein partners of MID1 and MID2 we undertook two separate yeast two-hybrid screens. Using this system we identified Alpha 4, a regulatory subunit of PP2-type phosphatases and a key component of the rapamycin-sensitive signaling pathway, as a strong interactor of both proteins. Analysis of domain-specific deletions has shown that the B-boxes of both MID1 and MID2 mediate the interaction with Alpha 4, the first demonstration in an RBCC protein of a specific role for the B-box region. In addition, we show that the MID1/2 coiled-coil motifs mediate both homo- and hetero-dimerisation, and that dimerisation is a prerequisite for association of the MID-Alpha 4 complex with microtubules. CONCLUSIONS: Our findings not only implicate Alpha 4 in the pathogenesis of Opitz GBBB syndrome but also support our earlier hypothesis that MID2 is a modifier of the X-linked phenotype. Of further note is the observation that Alpha 4 maps to Xq13 within the region showing linkage to FG (Opitz-Kaveggia) syndrome. Overlap in the clinical features of FG and Opitz GBBB syndromes warrants investigation of Alpha 4 as a candidate for causing FG syndrome

The impact of genetic counselling on risk perception in women with a family history of breast cancer.

Women with a family history of breast cancer generally self-refer because they have a feeling that their risk is high. However, they have, in general, only a hazy notion of the population risk of breast cancer and their own risk in relation to this. It is probable that they are helped by genetic counselling and, if at substantial risk, by annual mammography. However, the psychological impact of assigning true risk and the value of mammography need to be evaluated. We have assessed risk perception by questionnaire in 517 new referrals to a family history clinic and 200 women returning to the clinic at least 1 year after counselling. Correct assignment of population lifetime risk of breast cancer was 16% in the uninformed precounsel group and 33% in the post-counsel group, likewise personal risk was correct in 11% and 41% respectively. Post-counsel women were significantly more likely to retain information if they were sent a post-clinic letter or if they assessed their personal risk as too high initially

Circulating RANKL is inversely related to RANKL mRNA levels in bone in osteoarthritic males

Introduction The relationship of circulating levels of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) with the expression of these molecules in bone has not been established. The objective of this study was to measure, in humans, the serum levels of RANKL and OPG, and the corresponding levels in bone of mRNA encoding these proteins. Methods Fasting blood samples were obtained on the day of surgery from patients presenting for hip replacement surgery for primary osteoarthritis (OA). Intraoperatively, samples of intertrochanteric trabecular bone were collected for analysis of OPG and RANKL mRNA, using real time RT-PCR. Samples were obtained from 40 patients (15 men with age range 50 to 79 years, and 25 women with age range 47 to 87 years). Serum total RANKL and free OPG levels were measured using ELISA. Results Serum OPG levels increased over the age range of this cohort. In the men RANKL mRNA levels were positively related to age, whereas serum RANKL levels were negatively related to age. Again, in the men serum RANKL levels were inversely related (r = -0.70, P = 0.007) to RANKL mRNA levels. Also in the male group, RANKL mRNA levels were associated with a number of indices of bone structure (bone volume fraction relative to bone tissue volume, specific surface of bone relative to bone tissue volume, and trabecular thickness), bone remodelling (eroded surface and osteoid surface), and biochemical markers of bone turnover (serum alkaline phosphatase and osteocalcin, and urinary deoxypyridinoline). Conclusion This is the first report to show a relationship between serum RANKL and the expression of RANKL mRNA in bone.David Findlay, Mellick Chehade, Helen Tsangari, Susan Neale, Shelley Hay, Blair Hopwood, Susan Pannach, Peter O'Loughlin and Nicola Fazzalar

Physiological effects of KDM5C on neural crest migration and eye formation during vertebrate development

Background: Lysine-specific histone demethylase 5C (KDM5C) belongs to the jumonji family of demethylases and is specific for the di- and tri-demethylation of lysine 4 residues on histone 3 (H3K4 me2/3). KDM5C is expressed in the brain and skeletal muscles of humans and is associated with various biologically significant processes. KDM5C is known to be associated with X-linked mental retardation and is also involved in the development of cancer. However, the developmental significance of KDM5C has not been explored yet. In the present study, we investigated the physiological roles of KDM5C during Xenopus laevis embryonic development. Results: Loss-of-function analysis using kdm5c antisense morpholino oligonucleotides indicated that kdm5c knockdown led to small-sized heads, reduced cartilage size, and malformed eyes (i.e., small-sized and deformed eyes). Molecular analyses of KDM5C functional roles using whole-mount in situ hybridization, -galactosidase staining, and reverse transcription-polymerase chain reaction revealed that loss of kdm5c resulted in reduced expression levels of neural crest specifiers and genes involved in eye development. Furthermore, transcriptome analysis indicated the significance of KDM5C in morphogenesis and organogenesis. Conclusion: Our findings indicated that KDM5C is associated with embryonic development and provided additional information regarding the complex and dynamic gene network that regulates neural crest formation and eye development. This study emphasizes the functional significance of KDM5C in Xenopus embryogenesis; however, further analysis is needed to explore the interactions of KDM5C with specific developmental genes

A regional study of the Toro and Imburu Formation aquifers in the Papuan Basin, Papua New Guinea.

This study represents a regional review of the Toro and Imburu Formation aquifers in the fold belt and foreland regions of the Papuan Basin, Papua New Guinea (PNG). This study extends previous Toro aquifer studies in the Papuan Basin (Eisenberg 1993; Eisenberg et al., 1994; Kotaka 1996). A comprehensive data set was assembled containing all currently available well formation fluid pressure, salinity and temperature data. These data were used to calculate hydraulic potential (Hw) values, which were subsequently used to generate a regional potentiometric map for the Toro Sandstone reservoir and semi-regional maps for the Digimu, Hedinia and Iagifu Sandstone reservoirs of the Imburu Formation. The Toro potentiometric surface map generated in this study is consistent with an extensive hydrodynamic Toro aquifer system existing in the Papuan Basin Fold Belt. The Toro aquifer likely flows northwest to southeast parallel to the fold belt, from the Lavani Valley Toro outcrop (likely recharge region) in the Highlands, through to the Kutubu Complex, potentially via Hides, (possibly Angore) and the Mananda/South East Mananda Fields. The evidence for Toro aquifer hydrodynamic flow is strongest through the Kutubu Complex of fields, with water flow, entering via Agogo and exiting the fold belt, at the southern end of the Usano Field into the foreland of the basin. However, it should be noted that gas water contacts (GWCs) for Hides and Angore Fields are not yet available. These have been estimated in this study from Hides and Angore gas pressure gradient intersections with water pressure gradients identified from nearby wells (Lavani-1 and Egele-1). Therefore it is not currently possible to unequivocally identify a connected Toro aquifer system between Lavani Valley, (possibly Angore) and Hides. Nevertheless, the Lavani Valley-Hides-Mananda/South East Mananda system (LV-H-M/SEM) represents the most likely flow path for a Toro hydrodynamic aquifer model in the fold belt. Evidence for hydrodynamic Toro aquifer flow was identified in the opposite direction, in a southeast to northwest direction, in the South East Hedinia Field. Significant compartmentalisation of the Toro reservoir was identified in several Hinterland Fields and anticline structures (Egele, Angore, Moran, and Paua Fields along with the Kutubu and Makas Anticlines) and in the southeast region of the central fold belt (Gobe/South East Gobe Fields). Likely Toro aquifer flow exit points from fold belt into foreland were identified at the southern end of Usano at Iorogabaui-1 and at southern end of South East Mananada Field at Libano-1 involving the Bosavi Lineament. Possible northwest to southeast Toro aquifer flow was identified in the foreland region of the basin from the Stanley Field in the northwest to the sea in the southeast. The Komewu and Darai Fault systems appear to operate as barriers to northeast to southwest Toro aquifer flow in the foreland. Considerably less data were obtained in this study for the Digimu, Hedinia, Iagifu Sandstone reservoir aquifers compared to the Toro reservoir unit. However, key findings include; (1) for the Digimu Sandstone, hydrostatic and compartmentalised aquifer behaviour in the Agogo, Hedinia/Iagifu and Moran Fields, (2) for the Hedinia Sandstone, hydrodynamic aquifer behaviour in the Hedinia/Iagifu and South East Hedinia Fields and (3) for the Iagifu Sandstone, hydrodynamic aquifer behavior in the Hedinia/Iagifu Fields, a significant Hw step between the Agogo and Hedinia/Iagifu Fields (not seen with any of the other reservoir sandstones) and a compartmentalised aquifer in the Gobe/South East Gobe Fields (where it acts as the main hydrocarbon reservoir). The updated regional data and potentiometric maps generated in this study will assist subregional and field scale modelling of the Toro and Imburu Formation aquifers, future hydrodynamic trapping studies and provide increased confidence for hydrocarbon reserve determination in the Papuan Basin Fields.Thesis (B.Sc.(Hons.)) -- University of Adelaide, Australian School of Petroleum, 201

Towards characterisation of histone H1 gene transcription factors / by Blair Hopwood.

Bibliography : leaves 165-178.xii, 178, [73] leaves, [33] leaves of plates : ill. ; 30 cm.Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1993