Cystathionine ß-synthase gene inactivation dysregulates major urinary protein biogenesis and impairs sexual signaling in mice.

Reproductive success in mice depends on sexually dimorphic major urinary proteins (Mup) that facilitate interactions between females and males. Deletion of cystathionine ß-synthase (Cbs) gene, a metabolic gene important for homeostasis of one-carbon metabolism, impairs reproduction by causing female infertility in mice. Here, we examined Mup biogenesis and sexual signaling in Cbs-/- versus Cbs+/- mice. We found significantly reduced levels of total urinary Mup protein in male and female Cbs-/- versus Cbs+/- mice. SDS-PAGE/Western blot, ESI-MS, and RT-qPCR analyses of the liver, plasma, and urinary proteins identified a male-specific Mup20 in Cbs-/- , but not in Cbs+/- females. The 18 893 Da Mup20 became the most abundant in urine of Cbs-/- females and males. Effects of Cbs genotype on 18 645 Da, 18 693 Da, and 18 709 Da Mup species abundance were Mup- and sex-specific. Cbs genotype-dependent changes in hepatic Mups and Mup20 expression were similar at the protein and mRNA level. Changes in Mups, but not in Mup20, can be explained by downregulation of hepatic Zhx2 and Ghr receptors in Cbs-/- mice. Behavioral testing showed that Cbs+/- females ignored Cbs-/- male urine but were attracted to Cbs+/- male urine. Cbs+/- males ignored urine of Cbs-/- males but countermarked urine of other Cbs+/- males and were attracted to urines of Cbs-/- as well as Cbs+/- females. Cbs-/- males did not countermark urine of Cbs+/- males but were attracted to urines of Cbs+/- females. Taken together, these findings show that Cbs, a metabolic gene, interacts with the processes involved in Mup biogenesis that are essential for the maintenance of sexual dimorphism and signaling and suggest that dysregulation of these interactions impairs reproductive fitness in mice.

Filaggrin Expression and Processing Deficiencies Impair Corneocyte Surface Texture and Stiffness in Mice.

Abundant corneocyte surface protrusions, observed in patients with atopic dermatitis with filaggrin loss-of-function mutations, are inversely associated with levels of natural moisturizing factors (NMFs) in the stratum corneum. To dissect the etiological role of NMFs and filaggrin deficiency in surface texture alterations, we examined mouse models with genetic deficiencies in the synthesis or degradation of filaggrin monomers for NMFs, cell stiffness (elastic modulus) and corneocyte surface protrusion density (dermal texture index). Five neonatal and adult mouse models carrying inactivating mutations of SASPase (Sasp-/-), filaggrin (Flgft/ft and Flg-/-), filaggrin-hornerin (FlgHrnr-/-), and bleomycin hydrolase (Blmh-/-) were investigated. Sasp-/- and Flg-/- were on the hairless mouse background. Atomic force microscopy was used to determine elastic modulus and dermal texture index. Corneocytes of each neonatal as well as hairless adult knockout mouse exhibited an increased number of protrusions and decreased elastic modulus. In these mice, NMFs were reduced except for Sasp-/-. Dermal texture index was inversely correlated with NMFs and elastic modulus. Our findings demonstrate that any filaggrin-NMF axis deficiency can affect corneocyte mechanical properties in mice and likely in humans. Differences in NMFs and corneocyte surface texture between neonatal and adult as well as hairless and hairy mice emphasize the need for carefully selecting the most appropriate animal models for studies.

Mutations in Homocysteine Metabolism Genes Increase Keratin N-Homocysteinylation and Damage in Mice.

Genetic or nutritional deficiencies in homocysteine (Hcy) metabolism increase Hcy-thiolactone, which causes protein damage by forming isopetide bonds with lysine residues, generating N-Hcy-protein. In the present work, we studied the prevalence and genetic determinants of keratin damage caused by homocysteinylation. We found that in mammals and birds, 35 to 98% of Hcy was bound to hair keratin via amide or isopeptide bond (Hcy-keratin), while 2 to 65% was S-Hcy-keratin. A major fraction of hair Hcy-keratin (56% to 93%), significantly higher in birds than in mammals, was sodium dodecyl sulfate-insoluble. Genetic hyperhomocysteinemia significantly increased N-Hcy-keratin levels in the mouse pelage. N-Hcy-keratin was elevated 3.5-, 6.3-, and 11.7-fold in hair from Mthfr -/-, Cse -/-, or Cbs -/- mice, respectively. The accumulation of N-Hcy in hair keratin led to a progressive reduction of N-Hcy-keratin solubility in sodium dodecyl sulfate, from 0.39 ± 0.04 in wild-type mice to 0.19 ± 0.03, 0.14 ± 0.01, and 0.07 ± 0.03 in Mthfr -/-, Cse -/-, or Cbs -/-animals, respectively. N-Hcy-keratin accelerated aggregation of unmodified keratin in Cbs -/- mouse hair. Keratin methionine, copper, and iron levels in mouse hair were not affected by hyperhomocysteinemia. These findings provide evidence that pelage keratin is N-homocysteinylated in vivo in mammals and birds, and that this process causes keratin damage, manifested by a reduced solubility.

Effect of Peginterferon or Ribavirin Dosing on Efficacy of Therapy With Telaprevir in Treatment-Experienced Patients With Chronic Hepatitis C and Advanced Liver Fibrosis: A Multicenter Cohort Study.

We investigated the safety, efficacy, and impact of ribavirin and peginterferon dose reduction on complete early virologic response and sustained virologic response (SVR) to triple therapy with telaprevir in treatment-experienced patients with advanced liver fibrosis.Treatment was initiated for 211 patients who failed treatment with peginterferon and ribavirin, with bridging fibrosis (F3, n = 68) or cirrhosis (F4, n = 143), including 103 (49%) null-responders (NR), 30 (14%) partial responders (PR), and 78 (37%) relapsers (REL). Impaired liver function (ILF) platelets <100,000/mm or albumin <35 g/L were present in 40 patients. The distribution of hepatitis C virus subtypes was: 1a, 1b, or 1, with undetermined subtype for 10 (5%), 187 (89%), and 14 (6%) patients, respectively. Treatment was started with peginterferon alpha-2a or alpha-2b, ribavirin, and telaprevir at standard doses.The overall SVR24 rate was 56% and was lower in cirrhotic patients (NR: 35%, PR: 40%, and REL: 63%, respectively) than in patients with bridging fibrosis (NR: 50%, PR: 75%, and REL: 75%, respectively). The lowest probability of SVR24 was in NRs with ILF (26%). The SVR24 rate significantly decreased in NRs receiving <60% vs >60% of the total ribavirin dose (23% vs 44%, respectively) or <80% vs >80% of the total ribavirin dose (33% vs 48%, respectively). A significant SVR24 decrease was noted subsequent to a total peginterferon dose reduction, both when comparing patients who received <60% vs >60% of the total dose (NR: 0% vs 44%; REL: 33% vs 68%) and patients who received <80% vs >80% of the total dose (NR: 17% vs 50%; REL: 46% vs 71%).Serious adverse events were observed in 31 patients (15%). Deaths occurred in 4 patients. All of the deceased subjects were cirrhotic members of the ILF (baseline serum albumin level <35 g/L and/or platelet count <100,000/mm) group.Ribavirin dose reduction did not affect efficacy in REL but did in NR. Peginterferon dose reduction decreased the SVR24 rate for all groups, particularly in prior NR. ILF increased the risk of fatal complications with a low probability to achieve SVR24. One solution might be to provide wide and early access to novel, efficient, and safe interferon-free combinations to treatment-experienced patients, particularly those with liver cirrhosis.

Computer-aided detection of artificial pulmonary nodules using an ex vivo lung phantom: influence of exposure parameters and iterative reconstruction.

OBJECTIVES: To evaluate the influence of exposure parameters and raw-data based iterative reconstruction (IR) on the performance of computer-aided detection (CAD) of pulmonary nodules on chest multidetector computed tomography (MDCT). MATERIAL AND METHODS: Seven porcine lung explants were inflated in a dedicated ex vivo phantom shell and prepared with n=162 artificial nodules of a clinically relevant volume and maximum diameter (46-1063 µl, and 6.2-21.5 mm). n=118 nodules were solid and n=44 part-solid. MDCT was performed with different combinations of 120 and 80 kV with 120, 60, 30 and 12 mA*s, and reconstructed with both filtered back projection (FBP) and IR. Subsequently, 16 datasets per lung were subjected to dedicated CAD software. The rate of true positive, false negative and false positive CAD marks was measured for each reconstruction. RESULTS: The rate of true positive findings ranged between 88.9-91.4% for FBP and 88.3-90.1% for IR (n.s.) with most exposure settings, but was significantly lower with the combination of 80 kV and 12 mA*s (80.9% and 81.5%, respectively, p<0.05). False positive findings ranged between 2.3-8.1 annotations per lung. For nodule volumes <200 µl the rate of true positives was significantly lower than for >300 µl (p<0.05). Similarly, it was significantly lower for diameters <12 mm compared to ≥12 mm (p<0.05). The rate of true positives for solid and part-solid nodules was similar. CONCLUSIONS: Nodule CAD on chest MDCT is robust over a wide range of exposure settings. Noise reduction by IR is not detrimental for CAD, and may be used to improve image quality in the setting of low-dose MDCT for lung cancer screening.

Bleomycin hydrolase and hyperhomocysteinemia modulate the expression of mouse proteins involved in liver homeostasis.

The liver is the major contributor to homocysteine (Hcy) metabolism and fatty liver disease is associated with hyperhomocysteinemia. Bleomycin hydrolase (Blmh) is an aminohydrolase that also participates in Hcy metabolism by hydrolyzing Hcy-thiolactone. To gain insight into hepatic functions of Blmh, we analyzed the liver proteome of Blmh(-/-) and Blmh(+/+) mice in the absence and presence of diet-induced (high methionine) hyperhomocysteinemia using 2D IEF/SDS-PAGE gel electrophoresis and MALDI-TOF mass spectrometry. We identified eleven liver proteins whose expression was significantly altered as a result of the Blmh gene inactivation. The differential expression (Blmh(-/-) vs. Blmh(+/+)) of four liver proteins was lower, of two proteins was higher, and was further modified in mice fed with a hyperhomocysteinemic high-Met diet. The down-regulated proteins are involved in lipoprotein metabolism (ApoA1, ApoE), antigen processing (Psme1), energy metabolism (Atp5h, Gamt), methylglyoxal detoxification (Glo1), oxidative stress response (Sod1), and inactivation of catecholamine neurotransmitters (Comt). The two up-regulated proteins are involved in nitric oxide generation (Ddah1) and xenobiotic detoxification (Sult1c1). We also found that livers of Blmh(-/-) mice expressed a novel variant of glyoxalase domain-containing protein 4 (Glod4) by a post-transcriptional mechanism. Our findings suggest that Blmh interacts with diverse cellular processes-from lipoprotein metabolism, nitric oxide regulation, antigen processing, and energy metabolism to detoxification and antioxidant defenses-that are essential for liver homeostasis and that modulation of these interactions by hyperhomocysteinemia underlies the involvement of Hcy in fatty liver disease.

CT volumetry of artificial pulmonary nodules using an ex vivo lung phantom: influence of exposure parameters and iterative reconstruction on reproducibility.

OBJECTIVES: To evaluate the influence of exposure parameters and raw-data based iterative reconstruction (IR) on the measurement variability of computer-aided nodule volumetry on chest multidetector computed tomography (MDCT). MATERIALS AND METHODS: N=7 porcine lung explants were inflated in a dedicated ex vivo phantom and prepared with n=162 artificial nodules. MDCT was performed eight consecutive times (combinations of 120 and 80 kV with 120, 60, 30 and 12 mAs), and reconstructed with filtered back projection (FBP) and IR. Nodule volume and diameter were measured semi-automatically with dedicated software. The absolute percentage measurement error (APE) was computed in relation to the 120 kV 120 mAs acquisition. Noise was recorded for each nodule in every dataset. RESULTS: Mean nodule volume and diameter were 0.32 ± 0.15 ml and 12.0 ± 2.6mm, respectively. Although IR reduced noise by 24.9% on average compared to FBP (p<0.007), APE with IR was equal to or slightly higher than with FBP. Mean APE for volume increased significantly below a volume computed tomography dose index (CTDI) of 1.0 mGy: for 120 kV 12 mAs APE was 3.8 ± 6.2% (FBP) vs. 4.0 ± 5.2% (IR) (p<0.007); for 80 kV 12 mAs APE was 8.0 ± 13.0% vs. 9.3 ± 15.8% (n.s.), respectively. Correlating APE with image noise revealed that at identical noise APE was higher with IR than with FBP (p<0.05). CONCLUSIONS: Computer-aided volumetry is robust in a wide range of exposure settings, and reproducibility is reduced at a CTDI below 1.0 mGy only, but the error rate remains clinically irrelevant. Noise reduction by IR is not detrimental for measurement error in the setting of semi-automatic nodule volumetry on chest MDCT.