Growth Restriction in the Offspring of Mothers With Polycystic Ovary Syndrome.

Importance: Polycystic ovary syndrome (PCOS) is a common endocrine disorder, characterized by subfertility, increased risk of metabolic diseases, and pregnancy complications. Previous studies diverge regarding the association between maternal PCOS and newborn anthropometrics. Objective: To explore the association between maternal PCOS and newborn anthropometrics and the modifying effects of maternal body mass index, PCOS phenotype, and gestational diabetes. Design, Setting, and Participants: This cohort study followed up women from the first half of pregnancy to birth and combined data from 3 clinical trials of pregnant women with PCOS and a reference population consisting of participants in the Norwegian Mother, Father, and Child Cohort (MoBa) Study, with data from the Medical Birth Registry of Norway. The recruitment period for the clinical trials was between October 1, 2000, and August 31, 2017, and for MoBa, between July 1, 1999, and December 31, 2008. Participants included women with singleton pregnancies and live-born children. Data were analyzed from January 1 to June 15, 2023. Exposure: Maternal PCOS status. Main Outcomes and Measures: Newborn birth weight, birth length, and head circumference as continuous variables and z scores, and ponderal index (calculated as the birth weight in grams × 100 divided by the birth length in centimeters cubed), placenta weight, and ratio of birth weight to placenta weight (BWPW). Results: The cohort included 390 pregnant women with PCOS (mean [SD] age, 29.6 [4.2] years) and 68 708 women in the reference group (mean [SD] age, 30.4 [4.5] years). Offspring in the PCOS group had lower birth weight, birth length, and head circumference than in the reference group offspring. The estimated mean differences in z scores were -0.26 (95% CI, -0.38 to -0.14) for birth weight, -0.19 (95% CI, -0.33 to -0.05) for birth length, and -0.13 (95% CI, -0.26 to -0.01) for head circumference. The PCOS group also had a lower ponderal index (-0.04 [95% CI, -0.07 to -0.004] g × 100/cm3) and placenta weight (-24 [95% CI, -43 to -5)] g), and higher BWPW ratio (0.4 [95% CI, 0.3 to 0.5]). The association between growth restriction and PCOS was more apparent when additionally adjusting for body mass index. Neither PCOS phenotype nor gestational diabetes diagnosis was associated with neonatal anthropometry in women with PCOS. Conclusions and Relevance: In this cohort of mother-infant pairs, maternal PCOS status was associated with lower birth weight, shorter birth length, and smaller head circumference in the offspring. This growth restriction was more pronounced when adjusting for BMI, providing insight into the association between PCOS and body mass index. The study contributed to the understanding of how PCOS affects the offspring.

Metformin serum concentrations during pregnancy and post partum - A clinical study in patients with polycystic ovary syndrome.

BACKGROUND AND OBJECTIVES: Metformin is used to treat gestational diabetes. It is also used to treat women with polycystic ovary syndrome and has been shown to prevent late miscarriage and preterm birth. However, increased renal clearance during pregnancy causes a decline in serum concentrations of metformin. The aim of this study was to explore the time course of the pregnancy-related changes in metformin pharmacokinetics and the return to the non-pregnant state. METHOD: A subgroup of women in the PregMet2 study (n = 73) agreed to provide serum samples at three time-points in pregnancy (gestational weeks 19, 28 and 32) and once in post partum, (either 2, 4 or 8 weeks after delivery). Serum metformin concentrations were compared using a four-parameter logistic model. FINDINGS: The mean steady-state serum concentration of metformin during pregnancy was 9.39 µmoL/L, whereas the post partum concentration was 12.36 µmoL/L, an increase of 32% (p = 0,019). This change took place already during the first 2 weeks post partum. CONCLUSION: Clinicians who treat pregnant women with metformin should be aware of the significant decrease in metformin concentration mediated by pregnancy, and the rapid increase after delivery, as it may impact both the therapeutic efficacy and the risk of adverse drug reactions.

Gestational weight gain, appetite regulating hormones, and metformin treatment in polycystic ovary syndrome: A longitudinal, placebo-controlled study.

OBJECTIVE: To explore mechanisms that modulate gestational weight gain (GWG) in women with polycystic ovary syndrome (PCOS) and healthy controls. DESIGN: Sub-sample of randomised controlled trials (PCOS) combined with a prospective cohort (controls). SETTING: Eleven Norwegian, Swedish, and Icelandic hospitals. POPULATION: Pregnant women with PCOS treated with metformin (PCOS-M, n = 36) or placebo (PCOS-P, n = 37), and healthy pregnant women (HC, n = 15). METHODS: Serum levels of the appetite regulating hormones leptin, ghrelin, allopregnanolone, and soluble leptin receptor (sOB-R) were determined in the first and third trimesters. MAIN OUTCOME MEASURES: Excessive GWG (eGWG) relative to body mass index according to Institute of Medicine (IOM) guideline. Serum leptin/sOB-R ratio, or free-leptin-index (FLI), as biomarker of leptin sensitivity. Serum ghrelin and allopregnanolone levels. RESULTS: The overall prevalence of eGWG was 44% (38/86). Women with eGWG had higher first and third trimester FLI (P < 0.001), and lower third trimester allopregnanolone levels (P = 0.003) versus women with non-eGWG. The prevalence of eGWG was lower in PCOS-M versus PCOS-P (28% versus 62%, odds ratio = 0.4, 95% CI 0.2-0.8, P = 0.005). FLI decreased during pregnancy in PCOS-M (P = 0.01), but remained unaltered in PCOS-P and HC. Ghrelin and allopregnanolone levels were comparable in PCOS-M, PCOS-P and HC throughout pregnancy. CONCLUSION: Excessive GWG is associated with enhanced leptin resistance, and attenuated physiological increase in serum allopregnanolone levels during pregnancy. Metformin reduces the risk for eGWG and improves leptin sensitivity in pregnant women with PCOS. TWEETABLE ABSTRACT: Metformin counteracts excessive weight gain and leptin resistance in pregnant women with polycystic ovary syndrome.

Changes in Serum Cytokines Throughout Pregnancy in Women With Polycystic Ovary Syndrome.

CONTEXT: Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with low-grade inflammation and increased incidence of pregnancy complications, but its influence on the maternal immune system in pregnancy is unknown. Longitudinal serum cytokine profiling is a sensitive measure of the complex immunological dynamics of pregnancy. OBJECTIVE: This work aimed to determine the immunological dynamics of serum cytokines throughout pregnancy in women with PCOS and compare it to pregnancy in women without PCOS. METHODS: A post hoc analysis was conducted of longitudinal serum samples from 2 randomized, placebo-controlled multicenter studies of pregnant women with PCOS and 2 studies of pregnant women without PCOS. Pregnant women with PCOS (n = 358) and without PCOS (n = 258, controls) provided 1752 serum samples from 4 time points in pregnancy (weeks 10, 19, 32, and 36). Main outcome measures included maternal serum levels of 22 cytokines and C-reactive protein (CRP) at 4 time points in pregnancy. RESULTS: Women with PCOS showed marked immunological changes in serum cytokines throughout pregnancy. Compared to controls, women with PCOS showed higher levels of 17 cytokines and CRP at week 10 of pregnancy and a distinct cytokine development throughout pregnancy. The immunological dynamics in women with PCOS was significantly affected by maternal body mass index, smoking, and fetal sex. CONCLUSION: Pregnancy in women with PCOS was associated with a strong early mobilization of inflammatory and other serum cytokines persisting throughout pregnancy, indicating a more activated immune status. These findings provide a novel basis for further study of PCOS and pregnancy complications.

Use of metformin to treat pregnant women with polycystic ovary syndrome (PregMet2): a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Women with polycystic ovary syndrome (PCOS) have an increased risk of pregnancy complications. Epi-analysis of two previous randomised controlled trials that compared metformin with placebo during pregnancy in women with PCOS showed a significant reduction in late miscarriages and preterm births in the metformin group. The aim of this third randomised trial (PregMet2) was to test the hypothesis that metformin prevents late miscarriage and preterm birth in women with PCOS. METHODS: PregMet2 was a randomised, placebo-controlled, double-blind, multicentre trial done at 14 hospitals in Norway, Sweden, and Iceland. Singleton pregnant women with PCOS aged 18-45 years were eligible for inclusion. After receiving information about the study at their first antenatal visit or from the internet, women signed up individually to participate in the study. Participants were randomly assigned (1:1) to receive metformin or placebo by computer-generated random numbers. Randomisation was in blocks of ten for each country and centre; the first block had a random size between one and ten to assure masking. Participants were assigned to receive oral metformin 500 mg twice daily or placebo during the first week of treatment, which increased to 1000 mg twice daily or placebo from week 2 until delivery. Placebo tablets and metformin tablets were identical and participants and study personnel were masked to treatment allocation. The primary outcome was the composite incidence of late miscarriage (between week 13 and week 22 and 6 days) and preterm birth (between week 23 and week 36 and 6 days), analysed in the intention-to-treat population. Secondary endpoints included the incidence of gestational diabetes, preeclampsia, pregnancy-induced hypertension, and admission of the neonate to the neonatal intensive care unit. We also did a post-hoc individual participant data analysis of pregnancy outcomes, pooling data from the two previous trials with the present study. The study was registered with ClinicalTrials.gov, number NCT01587378, and EudraCT, number 2011-002203-15. FINDINGS: The study took place between Oct 19, 2012, and Sept 1, 2017. We randomly assigned 487 women to metformin (n=244) or placebo (n=243). In the intention-to-treat analysis, our composite primary outcome of late miscarriage and preterm birth occurred in 12 (5%) of 238 women in the metformin group and 23 (10%) of 240 women in the placebo group (odds ratio [OR] 0·50, 95% CI 0·22-1·08; p=0·08). We found no significant differences for our secondary endpoints, including incidence of gestational diabetes (60 [25%] of 238 women in the metformin group vs 57 [24%] of 240 women in the placebo group; OR 1·09, 95% CI 0·69-1·66; p=0·75). We noted no substantial between-group differences in serious adverse events in either mothers or offspring, and no serious adverse events were considered drug-related by principal investigators. In the post-hoc pooled analysis of individual participant data from the present trial and two previous trials, 18 (5%) of 397 women had late miscarriage or preterm delivery in the metformin group compared with 40 (10%) of 399 women in the placebo group (OR 0·43, 95% CI 0·23-0·79; p=0·004). INTERPRETATION: In pregnant women with PCOS, metformin treatment from the late first trimester until delivery might reduce the risk of late miscarriage and preterm birth, but does not prevent gestational diabetes. FUNDING: Research Council of Norway, Novo Nordisk Foundation, St Olav's University Hospital, and Norwegian University of Science and Technology.

Quantitative analysis of mammalian chromosome by scanning transmission soft X-ray microscopy.

Soft X-ray spectromicroscopy was applied to study the quantitative distribution of DNA and protein in a mammalian chromosome at the spatial resolution of 100 nm. The quantities of DNA and protein were evaluated using 1s-π* transition in the NEXAFS spectra at the nitrogen K absorption edge. DNA was not uniformly distributed in the chromosome and DNA/protein ratio was less than 0.497. The present analysis revealed the clues to identify other molecules that contribute to the absorption spectrum of the sample. The results suggested that accumulation of the absorption spectra of relevant molecules would support the refinement of the analysis.

Monitoring of hemostatic abnormalities in major orthopedic surgery patients treated with edoxaban by APTT waveform.

INTRODUCTION: An analysis of the activated partial thromboplastin time (APTT) in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE) was carried out. METHODS: The APTT waveform was analyzed in the above patients to monitor edoxaban administration. RESULTS: Of these 99 patients, 12 exhibited deep vein thrombosis, and 25 had massive bleeding. An increased biphasic pattern of the APTT waveform was observed after the administration of edoxaban, but there were no significant differences between the patients with and without complications. The peak times of acceleration, velocity, and 1/2 fibrin formation were significantly prolonged after the administration of edoxaban, especially in patients with massive bleeding, and were moderately correlated with the anti-Xa activity. While the heights of velocity and acceleration peak 2 were lower in patients receiving warfarin treatment than in those receiving edoxaban, the widths of these parameters were significantly longer. The height of 1/2 fibrin formation and the width of acceleration peaks 1 and 2 and the velocity were significantly increased after the administration of edoxaban. CONCLUSION: The peak time of the APTT waveform was significantly prolonged after the administration of edoxaban. The analysis of the APTT waveform may therefore be useful for the prediction of the risk of massive bleeding.

Serum macrophage migration inhibitory factor (MIF) levels after allogeneic hematopoietic stem cell transplantation.

Macrophage migration inhibitory factor (MIF) may play an important role in the pathogenesis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT), as MIF plays an important role to regulate the production of tumor necrosis factor-alpha (TNF-alpha), one of the inflammatory cytokines which induces and exacerbates aGVHD. We examined the association between serum MIF levels and aGVHD vs. chronic GVHD (cGVHD) in allo-SCT patients in this study. We found a significant increase in the peak serum MIF (14.46 ng +/- 1.47 ng/ml) at onset in patients that developed aGVHD (n = 23, P = 0.009). We also found that mean serum MIF levels in patients who developed extensive type cGVHD within 6 months (12.58 +/- 2.18 ng/ml, n = 13) were significantly higher than MIF levels before allo-HSCT (7.86 +/- 1.17 ng/ml, n = 19, P = 0.04). Therefore, we speculated that serum MIF levels increase during the active phase of both aGVHD and cGVHD.

Large complex formation of the inhibitor of caspase-activated DNase.

Inhibitor of caspase-activated DNase (ICAD) is required for correctly folding of CAD and inhibits nuclease activity of CAD in non-apoptotic cells. From proteomic analysis of the ICAD binding proteins, we revealed that over-expressed flag-ICAD bound other ICAD molecules. Purified recombinant ICAD protein showed three bands, 66 KDa, 132 KDa and 450 KDa, by native-PAGE. ICAD fused with glutathione-S-transferase (GST) was immunoprecipitated with anti-flag antibody from Jurkat cell lysates cotransfected with ICAD fused with either GST or flag expression vectors. When purified recombinant ICAD protein was separated by gel chromatography, the molecular weight of ICAD was detected at approximately 440 and 45 K. ICAD in extracts of wild type Jurkat cells also existed at approximately 440 and 45 K as measured by gel chromatography; so that fractions of CAD coincided with fractions of approximately 440 K of ICAD. These results indicate that ICAD and/or CAD appeared to form large complexes in Jurkat cells.

Indoleamine 2,3-dioxygenase is necessary for cytolytic activity of natural killer cells.

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan catabolic enzyme that is widely distributed in various tissues. In peripheral blood mononuclear cells (PBMCs), production of IDO by macrophages or dendritic cells has been reported to inhibit T-cell activation and proliferation. In the present study, we have determined that other phenotypes of PBMCs also express IDO. In cultures of PBMCs, IDO was found predominantly in monocyte by immunohistochemistry. Reverse transcriptase polymerase chain reaction analysis showed that IDO mRNA was expressed in T lymphocytes, B lymphocytes and natural killer (NK) cells and that expression was increased upon activation with interferon-gamma. The cytotoxicity of NK cells against K562 and HepG2 cells was reduced by IDO inhibitor. These results suggest that IDO in NK cells is essential for NK cells to generate killing activity against cancer cells.

Transcriptional suppression of the estrogen receptor by truncated estrogen receptor-alpha.

The estrogen receptor (ER) is composed of six major functional domains - the A/B domain as the activation function 1 domain, domain C as the DNA-binding domain, domain D as a hinge domain, and domain E/F as the ligand-dependent transcriptional domains. A novel protein (designated as SRB-RGS) that interacted with domains C and D of ER alpha (ER alpha C/D) repressed the transcriptional activity of ER alpha. In this study, we have examined whether ER alpha C/D releases transcriptional suppression of ER alpha by intrinsic SRB-RGS. The expression vector of ER alpha C/D was transfected to the human cancer cell, KPL-1, which expressed the intrinsic ER. Unexpectedly, transcriptional suppression of ER by ER alpha C/D was observed. COS-7 cells, which have no intrinsic ER, showed a similar suppression of ER alpha by co-transfection of ER alpha and ER alpha C/D. The DNA-binding and the estrogen-binding activities of ER alpha decreased on co-transfection of ER alpha C/D, suggesting a decrease in the receptor protein itself. It is likely that the degradation of ER by co-transfection caused the transcriptional suppression of the ER.

Linearization and integration of DNA into cells preferentially occurs at intrinsically curved regions from human LINE-1 repetitive element.

A bent DNA library was constructed from human genomic DNA, from which a new clone belonging to the human LINE-1 sequence family was isolated and characterized. This clone, with a length of 378 base pairs and termed HBC-1 (human bent clone-1), contained an intrinsically occurring curved DNA structure. By permutation analysis, the center of curvature of this fragment was mapped onto the nucleotide position 886 from the 5' terminus of the complete LINE-1 sequence. Reporter plasmids, which contain HBC-1, were effectively integrated into human chromosome, indicating that the bent DNA structure provides a preferential donor site for the integration of human LINE-1 sequences. The present finding may provide an explanation as to why some inactivated LINE-1 sequences on human chromosomes carry the deletion at their 5' termini.

Molecular cloning and characterization of a steroid receptor-binding regulator of G-protein signaling protein cDNA.

Steroid hormone receptors are composed of six major functional domains, i.e. the A/B domains as the activation function 1 domain (AF-1), domain C as the DNA-binding domain, domain D as a hinge domain and domain E/F as the ligand-dependent transcriptional domain (AF-2). They regulate gene transcription through interactions with various nuclear factors of their domains, such as AF-1 and AF-2. We have insufficient knowledge of the function of the DNA-binding domain (domain C) except for its DNA-binding function or the hinge domain (domain D). Therefore, we attempted to identify factors interacting with the domains by using a yeast two-hybrid system. Domains C and D of estrogen receptor alpha were used as a bait to isolate cDNA clones from a rat ovary cDNA library. We isolated the cDNA clone of a novel steroid receptor-binding protein bearing the regulator of G-protein signaling (RGS) designated as SRB-RGS. The protein repressed the transcriptional activity of estrogen receptor alpha, suggesting cross-talk of steroid hormones and peptide hormones (or growth factors) for signal transductions mediated by SRB-RGS.

CAD/DFF40 nuclease is dispensable for high molecular weight DNA cleavage and stage I chromatin condensation in apoptosis.

DNA degradation during apoptotic execution generally occurs at two levels: early as high molecular weight (HMW) fragments and later on as oligonucleosomal fragments. Two nucleases, CAD/CPAN/DFF40 and endonuclease G, can digest nuclear chromatin to produce the oligonucleosomal fragments, and it has been suggested that CAD might be responsible for HMW DNA cleavage. To more clearly define the role of CAD in nuclear disassembly, we have generated CAD(-/-) sublines of chicken DT40 cells in which the entire CAD open reading frame has been deleted. These cells grow normally and undergo apoptosis with kinetics essentially identical to wild type cells. However, they fail to undergo detectable oligonucleosomal fragmentation, proving that CAD is essential for this stage of DNA cleavage, at least in DT40 cells. Other aspects of nuclear disassembly, including HMW DNA cleavage and early stage apoptotic chromatin condensation against the nuclear periphery proceed normally in the absence of CAD. However, the final stages of chromatin condensation and nuclear fragmentation do not occur. Our results demonstrate that CAD is required for complete disassembly of the nucleus during apoptosis and reveal the existence of one or more as yet unidentified second factors responsible for HMW DNA cleavage and the early stages of apoptotic chromatin condensation.

Lipopolysaccharide induction of indoleamine 2,3-dioxygenase is mediated dominantly by an IFN-gamma-independent mechanism.

Indoleamine 2,3-dioxygenase (IDO) is a rate-limiting enzyme in the L-tryptophan-kynurenine pathway, which converts an essential amino acid, L-tryptophan, to N-formylkynurenine. It has been speculated that IFN-gamma is a dominant IDO inducer in vivo. The present study used IFN-gamma or TNF-alpha gene-disrupted mice and IFN-gamma antibody-treated mice to demonstrate that lipopolysaccharide (LPS)-induced systemic IDO is largely dependent on TNF-alpha rather than IFN-gamma. IFN-gamma-independent IDO induction was also demonstrated in vitro with LPS-stimulated monocytic THP-1 cells. These findings clearly indicate that there is an IFN-gamma-independent mechanism of IDO induction in addition to the IFN-gamma-dependent mechanism.

Activation of a novel microglial gene encoding a lysosomal membrane protein in response to neuronal apoptosis.

In an attempt to understand the molecular mechanism of microglial activation in response to neuronal death or degeneration, we have employed cerebellar cell cultures prepared from P7 rats and grown in normal K(+) (5.4 mM) medium. Under this condition, glial cells respond to degeneration and cell death of granule neurons that begins to occur at 4 days in vitro (DIV). Here we describe a novel gene, granule cell death-10 (gcd-10) that is expressed in microglia and up-regulated in an early period of granule cell death. gcd-10 is homologous to the mouse lysosomal-associated multispanning membrane protein (LAPTm5) with hematopoietic origin. Immunocytochemistry and vital staining with acridine orange revealed that GCD-10 was localized at the perinuclear area of cultured microglia and COS 1 cells infected with a GCD-10-expressing adenoviral vector. In cerebellar cell cultures, however, GCD-10 was markedly up-regulated and widely distributed to the cytoplasm, which paralleled the localization of the ED1 antigen, the lysosomal marker. In vivo, gcd-10 is expressed mainly in the brain and the spleen, and was up-regulated upon nerve injury in retina 7 days after optic nerve transection. These findings suggest that gcd-10 is involved in the dynamics of lysosomal membranes associated with microglial activation both in vitro and in vivo.

Expression of indoleamine 2,3-dioxygenase and tryptophan 2,3-dioxygenase in early concepti.

Indoleamine 2,3-dioxygenase (IDO)-initiated tryptophan degradation in the placenta has been implicated in the prevention of the allogeneic fetus rejection [Munn, Zhou, Attwood, Bondarev, Conway, Marshall, Brown, and Mellor (1998) Science 281, 1191-1193]. To determine how IDO is associated with the development of the fetus and placenta, the time course of IDO expression (tryptophan-degrading activity, IDO protein and IDO mRNA) in the embryonic and extra-embryonic tissues as well as maternal tissues of mice was examined. A high tryptophan-degrading activity was detected in early concepti on days 6.5 and 7.5, whereas IDO protein and its mRNA were not expressed during early gestation, but appeared 2-3 days later, lasted for about 3 days and declined rapidly thereafter. The expression of IDO basically coincided with the formation of the placenta. On the contrary, the early tryptophan-degrading activity was due to gene expression of tryptophan 2,3-dioxygenase (TDO), as shown by Northern and Western analysis. These findings indicate that IDO is transiently expressed in the placenta but that the expression does not last until birth, and that the IDO expression is preceded by expression of another tryptophan-degrading enzyme, TDO, in the maternal and/or embryonic tissues in early concepti.

Defective development of NK1.1+ T-cell antigen receptor alphabeta+ cells in zeta-associated protein 70 null mice with an accumulation of NK1.1+ CD3- NK-like cells in the thymus.

Development of natural killer 1.1+ (NK1.1+) CD3+ (NK1.1+ T) cells was analyzed in zeta-associated protein 70 (ZAP-70) null ((-/-)) mice. Both NK1.1+ TCRalphabeta+ and NK1.1+ TCRgammadelta+ cell populations were absent in the thymus and spleen. By contrast, the number of NK1.1+ CD3- cells was increased in these tissues. The NK1.1+ CD3- thymocytes in ZAP-70(-/-) mice had surface phenotypes in common with NK or NK1.1+ T cells. However, some of them were discordant either with NK cells or with NK1.1+ T cells. The NK1.1+ CD3- cells produced interferon-gamma upon stimulation with NK1.1 cross-linking in the presence of interleukin-2 and exhibited a substantial cytotoxicity against YAC-1 cells. Moreover, the generation of NK1.1+ T cells with invariant Valpha14Jalpha281 chains was induced from the NK1.1+ CD3- thymocytes following stimulation with phorbol myristate acetate and ionomycin in a neonatal thymic organ culture. An introduction of TCRalpha and beta transgenes to the ZAP-70(-/-) mice resulted in generation of an NK1.1+ TCRalphabeta(dim) population, whereas no substantial CD4+ CD8- or CD4- CD8+ population that expressed the introduced TCRalphabeta was generated in the mainstream T lineage. These findings demonstrate that ZAP-70 kinase is indispensable for the development of NK1.1+ T cells and that the unique NK1.1+ CD3- thymocytes in ZAP-70(-/-) mice contain immediate precursors of NK1.1+ T cells.

Inhibition of cytochrome c release in Fas-mediated signaling pathway in transgenic mice induced to express hepatitis C viral proteins.

Persistent hepatitis C virus (HCV) infection often progresses to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Numerous viruses have been reported to escape from apoptotic mechanism to maintain persistent infection. In the present study, we characterized the effect of HCV proteins on the Fas signal using HCV transgenic mice, which expressed core, E1, E2, and NS2 proteins, regulated by the Cre/loxP switching system. The transgene expression of HCV transgenic mice caused resistance to Fas antibody stimulated lethality. Apoptotic cell death in the liver of HCV protein expressing mice was significantly reduced compared with nonexpressing mice. Histopathological analysis and DNA fragmentation analysis revealed that the HCV proteins suppressed Fas-mediated apoptotic cell death. To identify the target pathway of HCV proteins, we characterized caspase activity. The activation of caspase-9 and -3/7 but not caspase-8 was inhibited by HCV proteins. Cytochrome c release from mitochondria was inhibited in HCV protein expressing mice. These results indicated that the expression of HCV proteins may directly or indirectly inhibit Fas-mediated apoptosis and death in mice by repressing the release of cytochrome c from mitochondria, thereby suppressing caspase-9 and -3/7 activation. These results suggest that HCV may cause persistent infection, as a result of suppression of Fas-mediated cell death.