Vaginal vault cytology tests: analysis of a decade of data from a UK tertiary centre

H. Stokes‐Lampard, S. Wilson, C. Waddell and L. Bentley Vaginal vault cytology tests: analysis of a decade of data from a UK tertiary centre Objectives: To examine temporal trends in the use of vault cytology tests in primary and secondary care and the demographics of those women tested. Methods: Retrospective analysis of routinely collected data concerning women who had a vault cytology test processed during a 10‐year period (1 April 1995 to 31 March 2005) at Birmingham Women’s NHS Foundation Trust. Results: A total of 8457 vault cytology tests from 3164 women (range 1–17 tests, median = 2) were processed, representing approximately 2% of the cervical cytology workload of the Department of Cytopathology at Birmingham Women's Hospital. There was a significant reduction in annual numbers processed (Pearson correlation ?0.958, P < 0.001). Significant abnormalities (mild dyskaryosis or worse) were detected in 4.5%, with malignancy being detected in <0.1%. The unsatisfactory cytology test rate was 10.7% overall. There was a reduction in the numbers of vault cytology tests coming from the community, hospital outpatient clinics and operating theatres over time (χ² for linear trend = 139.53, 9 d.f., P < 0.0001). Tests originating from community settings had the lowest disease detection rates: no malignancies and only two severe abnormalities were detected from almost 4000 primary care samples; abnormal results represented 2.8% (n = 113), of which the majority (n = 73) were borderline results. All cancers (n = 8) were detected in samples taken in gynaecology and colposcopy clinics. Conclusions: Vault cytology test usage appears to be reducing, particularly from outpatient clinics and primary care. Community detection rates are very low. Further research is required to establish the true costs and benefits of vaginal vault cytology.     

Colonic eosinophilic inflammation in experimental colitis is mediated by Ly6C(high) CCR2(+) inflammatory monocyte/macrophage-derived CCL11

Recent genome-wide association studies of pediatric inflammatory bowel disease have implicated the 17q12 loci, which contains the eosinophil-specific chemokine gene CCL11, with early-onset inflammatory bowel disease susceptibility. In the current study, we employed a murine model of experimental colitis to define the molecular pathways that regulate CCL11 expression in the chronic intestinal inflammation and pathophysiology of experimental colitis. Bone marrow chimera experiments showed that hematopoietic cell-derived CCL11 is sufficient for CCL11-mediated colonic eosinophilic inflammation. We show that dextran sodium sulfate (DSS) treatment promotes the recruitment of F4/80(+)CD11b(+)CCR2(+)Ly6C(high) inflammatory monocytes into the colon. F4/80(+)CD11b(+)CCR2(+)Ly6C(high) monocytes express CCL11, and their recruitment positively correlated with colonic eosinophilic inflammation. Phenotypic analysis of purified Ly6C(high) intestinal inflammatory macrophages revealed that these cells express both M1- and M2-associated genes, including Il6, Ccl4, Cxcl2, Arg1, Chi3l3, Ccl11, and Il10, respectively. Attenuation of DSS-induced F4/80(+)CD11b(+)CCR2(+)Ly6C(high) monocyte recruitment to the colon in CCR2(-/-) mice was associated with decreased colonic CCL11 expression, eosinophilic inflammation, and DSS-induced histopathology. These studies identify a mechanism for DSS-induced colonic eosinophilia mediated by Ly6C(high)CCR2(+) inflammatory monocyte/macrophage-derived CCL11.     

Cdk-inhibitory activity and stability of p27Kip1 are directly regulated by oncogenic tyrosine kinases

p27Kip1 controls cell proliferation by binding to and regulating the activity of cyclin-dependent kinases (Cdks). Here we show that Cdk inhibition and p27 stability are regulated through direct phosphorylation by tyrosine kinases. A conserved tyrosine residue (Y88) in the Cdk-binding domain of p27 can be phosphorylated by the Src-family kinase Lyn and the oncogene product BCR-ABL. Y88 phosphorylation does not prevent p27 binding to cyclin A/Cdk2. Instead, it causes phosphorylated Y88 and the entire inhibitory 3(10)-helix of p27 to be ejected from the Cdk2 active site, thus restoring partial Cdk activity. Importantly, this allows Y88-phosphorylated p27 to be efficiently phosphorylated on threonine 187 by Cdk2 which in turn promotes its SCF-Skp2-dependent degradation. This direct link between transforming tyrosine kinases and p27 may provide an explanation for Cdk kinase activities observed in p27 complexes and for premature p27 elimination in cells that have been transformed by activated tyrosine kinases.     

Targeted cell replacement with bone marrow cells for airway epithelial regeneration

It has been suggested that some adult bone marrow cells (BMC) can localize to the lung and develop tissue-specific characteristics including those of pulmonary epithelial cells. Here, we show that the combination of mild airway injury (naphthalene-induced) as a conditioning regimen to direct the site of BMC localization and transtracheal delivery of short-term cultured BMC enhances airway localization and adoption of an epithelial-like phenotype. Confocal analysis of airway and alveolar-localized BMC (fluorescently labeled) with epithelial markers shows expression of the pulmonary epithelial proteins, Clara cell secretory protein, and surfactant protein C. To confirm epithelial gene expression by BMC, we generated transgenic mice expressing green fluorescent protein (GFP) driven by the epithelial-specific cytokeratin-18 promoter and injected BMC from these mice transtracheally into wild-type recipients after naphthalene-induced airway injury. BMC retention in the lung was observed for at least 120 days following cell delivery with increasing GFP transgene expression over time. Some BMC cultured in vitro over time also expressed GFP transgene, suggesting epithelial transdifferentiation of the BMC. The results indicate that targeted delivery of BMC can promote airway regeneration.     

A short linear motif in BNIP3L (NIX) mediates mitochondrial clearance in reticulocytes

Elimination of defective mitochondria is essential for the health of long-lived, postmitotic cells. To gain insight into this process, we examined programmed mitochondrial clearance in reticulocytes. BNIP3L is a mitochondrial outer membrane protein that is required for clearance. It has been suggested that BNIP3L functions by causing mitochondrial depolarization, activating autophagy, or engaging the autophagy machinery. Here we showed in mice that BNIP3L activity localizes to a small region in its cytoplasmic domain, the minimal essential region (MER). The MER is a novel sequence, which comprises three contiguous hydrophobic amino acid residues, and flanking charged residues. Mutation of the central leucine residue causes complete loss of BNIP3L activity, and prevents rescue of mitochondrial clearance. Structural bioinformatics analysis predicts that the BNIP3L cytoplasmic domain lacks stable tertiary structure, but that the MER forms an α-helix upon binding to another protein. These findings support an adaptor model of BNIP3L, centered on the MER.     

Structural dissection of a gating mechanism preventing misactivation of ubiquitin by NEDD8's E1

Post-translational covalent modification by ubiquitin and ubiquitin-like proteins (UBLs) is a major eukaryotic mechanism for regulating protein function. In general, each UBL has its own E1 that serves as the entry point for a cascade. The E1 first binds the UBL and catalyzes adenylation of the UBL's C-terminus, prior to promoting UBL transfer to a downstream E2. Ubiquitin's Arg 72, which corresponds to Ala72 in the UBL NEDD8, is a key E1 selectivity determinant: swapping ubiquitin and NEDD8 residue 72 identity was shown previously to swap their E1 specificity. Correspondingly, Arg190 in the UBA3 subunit of NEDD8's heterodimeric E1 (the APPBP1-UBA3 complex), which corresponds to a Gln in ubiquitin's E1 UBA1, is a key UBL selectivity determinant. Here, we dissect this specificity with biochemical and X-ray crystallographic analysis of APPBP1-UBA3-NEDD8 complexes in which NEDD8's residue 72 and UBA3's residue 190 are substituted with different combinations of Ala, Arg, or Gln. APPBP1-UBA3's preference for NEDD8's Ala72 appears to be indirect, due to proper positioning of UBA3's Arg190. By contrast, our data are consistent with direct positive interactions between ubiquitin's Arg72 and an E1's Gln. However, APPBP1-UBA3's failure to interact with a UBL having Arg72 is not due to a lack of this favorable interaction, but rather arises from UBA3's Arg190 acting as a negative gate. Thus, parallel residues from different UBL pathways can utilize distinct mechanisms to dictate interaction selectivity, and specificity can be amplified by barriers that prevent binding to components of different conjugation cascades.