Insulin resistance in polycystic ovary syndrome (PCOS) results from a postbinding defect in signaling. Insulin receptor and insulin receptor substrate (IRS)-1 serine hyperphosphorylation by an unidentified kinase(s) contributes to this defect. We investigated whether insulin resistance is selective, affecting metabolic but not mitogenic pathways, in skeletal muscle as it is in cultured skin fibroblasts in PCOS. Extracellular signal-regulated kinase (ERK)1/2 activation was increased in skeletal muscle tissue and in cultured myotubes basally and in response to insulin in women with PCOS compared with control women. Mitogen-activated/extracellular signal-regulated kinase kinase (MEK)1/2 was also activated in PCOS, whereas p38 mitogen-activated protein kinase phosphorylation and signaling from the insulin receptor to Grb2 was similar in both groups. The activity of p21Ras was decreased and Raf-1 abundance increased in PCOS, suggesting that altered mitogenic signaling began at this level. MEK1/2 inhibition reduced IRS-1 Ser 312 phosphorylation and increased IRS-1 association with the p85 subunit of phosphatidylinositol 3-kinase in both groups. We conclude that in PCOS skeletal muscle, 1) mitogenic signaling is enhanced in vivo and in culture, 2) ERK1/2 activation inhibits association of IRS-1 with p85 via IRS-1 Ser 312 phosphorylation, and 3) ERK1/2 activation may play a role in normal feedback of insulin signaling and contribute to resistance to insulin's metabolic actions in PCOS. Diabetes 55: [751][752][753][754][755][756][757][758][759] 2006

Osteoblast induction and differentiation in developing long bones is dynamically controlled by the opposing action of transcriptional activators and repressors. In contrast to the long list of activators that have been discovered over past decades, the network of repressors is not well-defined. Here we identify the expression of Foxp1/2/4 proteins, comprised of Forkhead-box (Fox) transcription factors of the Foxp subfamily, in both perichondrial skeletal progenitors and proliferating chondrocytes during endochondral ossification. Mice carrying loss-of-function and gain-of-function Foxp mutations had gross defects in appendicular skeleton formation. At the cellular level, over-expression of Foxp1/2/4 in chondroctyes abrogated osteoblast formation and chondrocyte hypertrophy. Conversely, single or compound deficiency of Foxp1/2/4 in skeletal progenitors or chondrocytes resulted in premature osteoblast differentiation in the perichondrium, coupled with impaired proliferation, survival, and hypertrophy of chondrocytes in the growth plate. Foxp1/2/4 and Runx2 proteins interacted in vitro and in vivo, and Foxp1/2/4 repressed Runx2 transactivation function in heterologous cells. This study establishes Foxp1/2/4 proteins as coordinators of osteogenesis and chondrocyte hypertrophy in developing long bones and suggests that a novel transcriptional repressor network involving Foxp1/2/4 may regulate Runx2 during endochondral ossification.

Objectives. To evaluate pregnancy outcomes and its determinants in women with polycystic ovary syndrome (PCOS). Methods. Two-hundred and twenty pregnant PCOS and 594 healthy women were followed from early pregnancy. Incidences of gestational diabetes mellitus (GDM), pregnancy-induced hypertension (PIH), preterm birth, twinning, and fetal growth restriction (FGR) were determined. Results. The incidence of GDM was notably higher among all PCOS combined (54.9%; OR: 2.9, 95% CI: 2.0–4.1) and PCOS subgroups, whether they conceived spontaneously (51.5%; OR: 3.3, 95% CI: 2.0–5.4), or via IVF-ET or ovarian stimulation, compared with controls (14.3%; P < 0.001). The incidence of PIH was also higher among all PCOS (10.4%; OR: 2.2, 95% CI: 1.1–4.4) and the subgroup conceiving spontaneously (11.8%; OR: 2.6, 95% CI: 1.1–6.2; P < 0.001) but not for those conceiving with IVF-ET (9.1%) or ovarian stimulation (9.4%). Lean women with PCOS (BMI <24 kg/m2) had higher incidences of GDM (51.1% versus 14.5%; OR: 5.6, 95% CI: 3.4–9.0) and PIH (8.9% versus 3.2%; OR: 3.0, 95% CI: 1.3–7.1) than lean controls. PCOS woemn with normal glucose tolerance had higher risk for PIH than their comparable control group (OR: 4.0, 95% CI: 1.3–11.7). Conclusion. This study suggested that PCOS is an independent risk factor for the development of GDM and PIH. This trial is registered with ChiCTR-RCC-11001824.

SummaryWe have investigated the expression of the ectoenzyme dipeptidylpeptidase IV (DPP IV)/CD26 on lymphocytes obtained from patients with B chronic lymphocytic leukaemia (B-CLL) and compared it with healthy subjects. Using two-colour immunofluorescence analysis with CD26 and CD20 or CD23 monoclonal antibodies, CD26 was found undetectable on peripheral resting B-cells (CD20 + CD23 -) from normal donors whereas it was expressed on B-cells activated in vitro with interleukin (IL)-4 and Staphylococcus aureus strain cowan I (CD20 + CD23 + ). The expression of CD26 on leukaemic B-cells (CD20 + CD23 + ) was clearly induced in 22 out of 25 patients examined. Consequently, induced levels of CD26 cell surface expression on either normal activated and malignant B-cells coincided with the enhancement of DPP IV activity detected on the surface of these cells. Reverse transcription polymerase chain reaction analyses showed that the transcript levels of the CD26 gene was higher in normal activated B-cells and B-CLL cells than in resting B-cells, suggesting that CD26 was expressed at the level of transcriptional activation. These observations provide evidence of the abnormal expression of DPPIV/CD26 in B-CLL which, therefore, may be considered as a novel marker for B-CLL. Further investigation in relation to CD26 expression and other B malignancies needs to be defined.