SIN-3 acts in distinct complexes to regulate the germline transcriptional program in Caenorhabditis elegans

The transcriptional co-regulator SIN3 influences gene expression through multiple interactions that include histone deacetylases. Haploinsufficiency and mutations in SIN3 are the underlying cause of Witteveen-Kolk syndrome and related intellectual disability and autism syndromes, emphasizing its key role in development. However, little is known about the diversity of its interactions and functions in developmental processes. Here, we show that loss of SIN-3, the single SIN3 homolog in Caenorhabditis elegans, results in maternal-effect sterility associated with de-regulation of the germline transcriptome, including de-silencing of X-linked genes. We identify at least two distinct SIN3 complexes containing specific histone deacetylases and show that they differentially contribute to fertility. Single-cell, single-molecule fluorescence in situ hybridization reveals that in sin-3 mutants the X chromosome becomes re-expressed prematurely and in a stochastic manner in individual germ cells, suggesting a role for SIN-3 in its silencing. Furthermore, we identify histone residues whose acetylation increases in the absence of SIN-3. Together, this work provides a powerful framework for the in vivo study of SIN3 and associated proteins.

Implementation Outcomes of Strategies to Promote Short-Course Radiation for Nonspine Bone Metastases in an Academic-Community Partnership: Survey Results from the ALIGNMENT Trial

PURPOSE/OBJECTIVE(S)

Local treatment of nonspine bone metastases has become increasingly complex, resulting in physician practice variability nationwide. The purpose of this study was to assess physician perceptions of 3 implementation strategies to promote adoption of short course radiotherapy (RT) for nonspine bone metastases.

MATERIALS/METHODS

ALIGNMENT ("Alliance Group for Bone Metastasis") was a multi-institutional stepped wedge cluster randomized implementation trial testing strategies to increase use of ≤5 fractions for nonspine bone metastases conducted across 3 clinical sites in an academic-community partnership. Strategies included a) multidisciplinary consensus guidelines, b) e-Consults, an email-based consultation platform, and c) personalized audit and feedback (A&F) reports with peer comparison. Using the Proctor et al. framework and validated questions from Weiner et al., physician surveys were used to assess each strategy's usefulness, acceptability (i.e., "I welcome [strategy]"), appropriateness (i.e., "[strategy] seems like a good match"), and feasibility (i.e., "[strategy] seems implementable" or "easy to use"). Survey responses were anonymized, so Fisher's Exact test was used to compare proportions with significance set at p<0.05.

RESULTS

Overall, 29 of 38 and 30 of 38 physicians participated in the pre- and post-implementation surveys, respectively, with 80% completing both. Pre-implementation, guidelines was most often ranked 1st in terms of usefulness (61%), followed by eConsults (38%) and A&F (3%). Post-implementation, guidelines and eConsults had the most and least favorable acceptability, appropriateness, and feasibility scores, respectively (Table), with 77% of physicians being likely to recommend the guidelines to other oncologists. In contrast, while 43% of physicians reported having at least 1 difficult clinical question regarding bone metastases during the study, only 33% of physicians preferred eConsults, while 50% preferred reaching out to a friend/colleague. Lastly, although A&F had the lowest perceived usefulness pre-implementation, A&F had the greatest increase in acceptability (72%→90%; p = 0.10), appropriateness (66%→90%; p = 0.03) feasibility ("implementable": 59%→93%, p = 0.002; "easy to use": 45%→93%, p<0.001).

CONCLUSION

In this multicenter trial, all strategies were acceptable, appropriate, and feasible, with guidelines and A&F showing the most favorable outcomes post-implementation. While guidelines were assessed as the most useful, A&F had significant increases in appropriateness and feasibility.

Loss of SET1/COMPASS methyltransferase activity reduces lifespan and fertility in Caenorhabditis elegans

Changes in histone post-translational modifications are associated with aging through poorly defined mechanisms. Histone 3 lysine 4 (H3K4) methylation at promoters is deposited by SET1 family methyltransferases acting within conserved multiprotein complexes known as COMPASS. Previous work yielded conflicting results about the requirement for H3K4 methylation during aging. Here, we reassessed the role of SET1/COMPASS-dependent H3K4 methylation in Caenorhabditis elegans lifespan and fertility by generating set-2(syb2085) mutant animals that express a catalytically inactive form of SET-2, the C. elegans SET1 homolog. We show that set-2(syb2085) animals retain the ability to form COMPASS, but have a marked global loss of H3K4 di- and trimethylation (H3K4me2/3). Reduced H3K4 methylation was accompanied by loss of fertility, as expected; however, in contrast to earlier studies, set-2(syb2085) mutants displayed a significantly shortened, not extended, lifespan and had normal intestinal fat stores. Other commonly used set-2 mutants were also short-lived, as was a cfp-1 mutant that lacks the SET1/COMPASS chromatin-targeting component. These results challenge previously held views and establish that WT H3K4me2/3 levels are essential for normal lifespan in C. elegans.

Pre-implantation alcohol exposure induces lasting sex-specific DNA methylation programming errors in the developing forebrain

Background

Prenatal alcohol exposure is recognized for altering DNA methylation profiles of brain cells during development, and to be part of the molecular basis underpinning Fetal Alcohol Spectrum Disorder (FASD) etiology.  However, we have negligible information on the effects of alcohol exposure during pre-implantation, the early embryonic window marked with dynamic DNA methylation reprogramming, and on how this may rewire the brain developmental program.

Results

Using a pre-clinical in vivo mouse model, we show that a binge-like alcohol exposure during pre-implantation at the 8-cell stage leads to surge in morphological brain defects and adverse developmental outcomes during fetal life. Genome-wide DNA methylation analyses of fetal forebrains uncovered sex-specific alterations, including partial loss of DNA methylation maintenance at imprinting control regions, and abnormal de novo DNA methylation profiles in various biological pathways (e.g., neural/brain development).

Conclusion

These findings support that alcohol-induced DNA methylation programming deviations during pre-implantation could contribute to the manifestation of neurodevelopmental phenotypes associated with FASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01151-0.

Developmental genome-wide DNA methylation asymmetry between mouse placenta and embryo

In early embryos, DNA methylation is remodelled to initiate the developmental program but for mostly unknown reasons, methylation marks are acquired unequally between embryonic and placental cells. To better understand this, we generated high-resolution DNA methylation maps of mouse mid-gestation (E10.5) embryo and placenta. We uncovered specific subtypes of differentially methylated regions (DMRs) that contribute directly to the developmental asymmetry existing between mid-gestation embryonic and placental DNA methylation patterns. We show that the asymmetry occurs rapidly during the acquisition of marks in the post-implanted conceptus (E3.5-E6.5), and that these patterns are long-lasting across subtypes of DMRs throughout prenatal development and in somatic tissues. We reveal that at the peri-implantation stages, the de novo methyltransferase activity of DNMT3B is the main driver of methylation marks on asymmetric DMRs, and that DNMT3B can largely compensate for lack of DNMT3A in the epiblast and extraembryonic ectoderm, whereas DNMT3A can only partially compensate in the absence of DNMT3B. However, as development progresses and as DNMT3A becomes the principal de novo methyltransferase, the compensatory DNA methylation mechanism of DNMT3B on DMRs becomes less effective.

Physical and functional interaction between SET1/COMPASS complex component CFP-1 and a Sin3S HDAC complex in C. elegans

The CFP1 CXXC zinc finger protein targets the SET1/COMPASS complex to non-methylated CpG rich promoters to implement tri-methylation of histone H3 Lys4 (H3K4me3). Although H3K4me3 is widely associated with gene expression, the effects of CFP1 loss vary, suggesting additional chromatin factors contribute to context dependent effects. Using a proteomics approach, we identified CFP1 associated proteins and an unexpected direct link between Caenorhabditis elegans CFP-1 and an Rpd3/Sin3 small (SIN3S) histone deacetylase complex. Supporting a functional connection, we find that mutants of COMPASS and SIN3 complex components genetically interact and have similar phenotypic defects including misregulation of common genes. CFP-1 directly binds SIN-3 through a region including the conserved PAH1 domain and recruits SIN-3 and the HDA-1/HDAC subunit to H3K4me3 enriched promoters. Our results reveal a novel role for CFP-1 in mediating interaction between SET1/COMPASS and a Sin3S HDAC complex at promoters.

An exploratory analysis of individuals with multiple episodes of different reportable diseases, Montreal, 1990-2012

OBJECTIVES

Studies of public health reporting have only examined multiple episodes of the same communicable disease within an individual. We aimed to characterize Montreal residents with multiple reportable disease episodes from 1990 to 2012, while accounting for all types of reportable diseases.

STUDY DESIGN

Retrospective cohort study.

METHODS

We performed an exploratory analysis using descriptive statistics, contingency tables, and logistic regression.

RESULTS

There were 157,839 individuals with at least one disease report and a total of 179,455 disease reports. The 9.8% of subjects with more than one episode accounted for 20.7% of all reported episodes. Among subjects with four or fewer episodes, 54.0% were women, while 74.3% of subjects with five or more episodes were men. Subjects with multiple episodes were more likely to be reported for sexually transmitted infections than were persons with a single episode [difference of proportions: 10.4% (95% CI: 10.0%-10.9%)] and to reside in the neighbourhood encompassing Montreal's gay village.

CONCLUSIONS

Individuals with multiple communicable disease reports place a large burden on public health officials. These results may help guide investigation and prevention efforts to reduce the number of excess episodes.

Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis

In this study, Wassef et al. used mouse and human models to show that the high expression of Polycomb protein EZH2 in solid tumors is a consequence, not a cause, of tumorigenesis and that low abundance or deletion of EZH2 relative to proliferation is linked to poor prognosis and transcriptional instability.

Alterations of chromatin modifiers are frequent in cancer, but their functional consequences often remain unclear. Focusing on the Polycomb protein EZH2 that deposits the H3K27me3 (trimethylation of Lys27 of histone H3) mark, we showed that its high expression in solid tumors is a consequence, not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process malfunctions in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes actually indicate poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes that are consequences of EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.

The EULAR Outcome Measures Library: development and an example from a systematic review for systemic lupus erythematous instruments

OBJECTIVES

Patient reported outcomes (PROs) are relevant in rheumatology. Variable accessibility and validity of commonly used PROs are obstacles to homogeneity in evidence synthesis. The objective of this project was to provide a comprehensive library of "validated PROs".

METHODS

A launch meeting with rheumatologists, PROs methodological experts, and patients, was held to define the library's aims and scope, and basic requirements. To feed the library we performed systematic reviews on selected diseases and domains. Relevant information on PROs was collected using standardised data collection forms based on the COSMIN checklist.

RESULTS

The EULAR Outcomes Measures Library (OML), whose aims are to provide and to advise on PROs on a user-friendly manner albeit based on scientific grounds, has been launched and made accessible to all. PROs currently included cover any domain and, are generic or specifically target to the following diseases: rheumatoid arthritis, osteoarthritis, spondyloarthritis, low back pain, systemic lupus erythematosus, gout, osteoporosis, juvenile idiopathic arthritis, and fibromyalgia. Up to 236 instruments (106 generic and 130 specific) have been identified, evaluated, and included. The systematic review for SLE, which yielded 10 specific instruments, is presented here as an example. The OML website includes, for each PRO, information on the construct being measured and the extent of validation, recommendations for use, and available versions; it also contains a glossary on common validation terms.

CONCLUSIONS

The OML is an in progress library led by rheumatologists, related professionals and patients, that will help to better understand and apply PROs in rheumatic and musculoskeletal diseases.

Jarid2 Methylation via the PRC2 Complex Regulates H3K27me3 Deposition during Cell Differentiation

Polycomb Group (PcG) proteins maintain transcriptional repression throughout development, mostly by regulating chromatin structure. Polycomb Repressive Complex 2 (PRC2), a component of the Polycomb machinery, is responsible for the methylation of histone H3 lysine 27 (H3K27me2/3). Jarid2 was previously identified as a cofactor of PRC2, regulating PRC2 targeting to chromatin and its enzymatic activity. Deletion of Jarid2 leads to impaired orchestration of gene expression during cell lineage commitment. Here, we reveal an unexpected crosstalk between Jarid2 and PRC2, with Jarid2 being methylated by PRC2. This modification is recognized by the Eed core component of PRC2 and triggers an allosteric activation of PRC2’s enzymatic activity. We show that Jarid2 methylation is important to promote PRC2 activity at a locus devoid of H3K27me3 and for the correct deposition of this mark during cell differentiation. Our results uncover a regulation loop where Jarid2 methylation fine-tunes PRC2 activity depending on the chromatin context.

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PRC2 methylates Jarid2 on K116

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Jarid2 methylation promotes PRC2 activity

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H3K27me3 and Jarid2-K116me3 bind to the aromatic cage of Eed

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Jarid2 methylation regulates H3K27me3 deposition during ESC differentiation

Oncology patient-reported claims: maximising the chance for success

Objectives/purpose:

To review Patient Reported Outcome (PRO) labelling claims achieved in oncology in Europe and in the United States and consider the benefits, and challenges faced.

Methods:

PROLabels database was searched to identify oncology products with PRO labelling approved in Europe since 1995 or in the United States since 1998. The US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) websites and guidance documents were reviewed. PUBMED was searched for articles on PRO claims in oncology.

Results:

Among all oncology products approved, 22 were identified with PRO claims; 10 in the United States, 7 in Europe, and 5 in both. The language used in the labelling was limited to benefit (e.g. “…resulted in symptom benefits by significantly prolonging time to deterioration in cough, dyspnoea, and pain, versus placebo”) and equivalence (e.g. “no statistical differences were observed between treatment groups for global QoL”). Seven products used a validated HRQoL tool; two used symptom tools; two used both; seven used single-item symptom measures (one was unknown). The following emerged as likely reasons for success: ensuring systematic PRO data collection; clear rationale for pre-specified endpoints; adequately powered trials to detect differences and clinically significant changes; adjusting for multiplicity; developing an a priori statistical analysis plan including primary and subgroup analyses, dealing with missing data, pooling multiple-site data; establishing clinical versus statistical significance; interpreting failure to detect change. End-stage patient drop-out rates and cessation of trials due to exceptional therapeutic benefit pose significant challenges to demonstrating treatment PRO improvement.

Conclusions:

PRO labelling claims demonstrate treatment impact and the trade-off between efficacy and side effects ultimately facilitating product differentiation. Reliable and valid instruments specific to the desired language, claim, and target population are required. Practical considerations include rationale for study endpoints, transparency in assumptions, and attention to subtle variations in data.

Drosophila Set1 is the major histone H3 lysine 4 trimethyltransferase with role in transcription

Histone H3 lysine 4 trimethylation (H3K4me3) is a major hallmark of promoter-proximal histones at transcribed genes. Here, we report that a previously uncharacterized Drosophila H3K4 methyltransferase, dSet1, and not the other putative histone H3K4 methyltransferases (Trithorax; Trithorax-related protein), is predominantly responsible for histone H3K4 trimethylation. Functional and proteomics studies reveal that dSet1 is a component of a conserved H3K4 trimethyltransferase complex and polytene staining and live cell imaging assays show widespread association of dSet1 with transcriptionally active genes. dSet1 is present at the promoter region of all tested genes, including activated Hsp70 and Hsp26 heat shock genes and is required for optimal mRNA accumulation from the tested genes. In the case of Hsp70, the mRNA production defect in dSet1 RNAi-treated cells is accompanied by retention of Pol II at promoters. Our data suggest that dSet1-dependent H3K4me3 is responsible for the generation of a chromatin structure at active promoters that ensures optimal Pol II release into productive elongation.

Type 1 wild poliovirus and putative enterovirus 109 in an outbreak of acute flaccid paralysis in Congo, October-November 2010

An outbreak of flaccid paralysis syndrome in adults is ongoing in Congo. Molecular analysis of faecal, throat and cerebrospinal samples identified wildtype 1 poliovirus and an additional enterovirus C strain related to enterovirus 109 as the cause. As of 22 November, the cumulative number of cases was 409, of which 169 (41.3%) were fatal. This is one of the largest wild type 1 poliovirus outbreaks ever described associated with an unusually high case fatality rate.

Different prelamin A forms accumulate in human fibroblasts: a study in experimental models and progeria

Lamin A is a component of the nuclear lamina mutated in a group of human inherited disorders known as laminopathies. Among laminopathies, progeroid syndromes and lipodystrophies feature accumulation of prelamin A, the precursor protein which, in normal cells, undergoes a multi-step processing to yield mature lamin A. It is of utmost importance to characterize the prelamin A form accumulated in each laminopathy, since existing evidence shows that drugs acting on protein processing can improve some pathological aspects.We report that two antibodies raised against differently modified prelamin A peptides show a clear specificity to full-length prelamin A or carboxymethylated farnesylated prelamin A, respectively. Using these antibodies, we demonstrated that inhibition of the prelamin A endoprotease ZMPSTE24 mostly elicits accumulation of full-length prelamin A in its farnesylated form, while loss of the prelamin A cleavage site causes accumulation of carboxymethylated prelamin A in progeria cells. These results suggest a major role of ZMPSTE24 in the first prelamin A cleavage step.

Cocaine-conditioned locomotion in dopamine transporter, norepinephrine transporter and 5-HT transporter knockout mice

The behavioral effects of cocaine are affected by gene knockout (KO) of the dopamine transporter (DAT), the serotonin transporter (SERT) and the norepinephrine transporter (NET). The relative involvement of each of these transporters varies depending on the particular behavioral response to cocaine considered, as well as on other factors such as genetic background of the subjects. Interestingly, the effects of these gene knockouts on cocaine-induced locomotion are quite different from those on reward assessed in the conditioned place preference paradigm. To further explore the role of these genes in the rewarding effects of cocaine, the ability of five daily injections of cocaine to induce conditioned locomotion was assessed in DAT, SERT and NET KO mice. Cocaine increased locomotor activity acutely during the initial conditioning session in SERT KO and NET KO, but not DAT KO, mice. Surprisingly, locomotor responses in the cocaine-paired subjects diminished over the five conditioning sessions in SERT KO mice, while locomotor responses increased in DAT KO mice, despite the fact that they did not demonstrate any initial locomotor responses to cocaine. Cocaine-induced locomotion was unchanged over the course of conditioning in NET KO mice. In the post-conditioning assessment, conditioned locomotion was not observed in DAT KO mice, and was reduced in SERT KO and NET KO mice. These data reaffirm the central role of dopamine and DAT in the behavioral effects of cocaine. Furthermore, they emphasize the polygenic basis of cocaine-mediated behavior and the non-unitary nature of drug reward mechanisms, particularly in the context of previous studies that have shown normal cocaine-conditioned place preference in DAT KO mice.

Different prelamin A forms accumulate in human fibroblasts: a study in experimental models and progeria

Lamin A is a component of the nuclear lamina mutated in a group of human inherited disorders known as laminopathies. Among laminopathies, progeroid syndromes and lipodystrophies feature accumulation of prelamin A, the precursor protein which, in normal cells, undergoes a multi-step processing to yield mature lamin A. It is of utmost importance to characterize the prelamin A form accumulated in each laminopathy, since existing evidence shows that drugs acting on protein processing can improve some pathological aspects. We report that two antibodies raised against differently modified prelamin A peptides show a clear specificity to full-length prelamin A or carboxymethylated farnesylated prelamin A, respectively. Using these antibodies, we demonstrated that inhibition of the prelamin A endoprotease ZMPSTE24 mostly elicits accumulation of full-length prelamin A in its farnesylated form, while loss of the prelamin A cleavage site causes accumulation of carboxymethylated prelamin A in progeria cells. These results suggest a major role of ZMPSTE24 in the first prelamin A cleavage step.

Human lipodystrophies linked to mutations in A-type lamins and to HIV protease inhibitor therapy are both associated with prelamin A accumulation, oxidative stress and premature cellular senescence

Lipodystrophic syndromes associated with mutations in LMNA, encoding A-type lamins, and with HIV antiretroviral treatments share several clinical characteristics. Nuclear alterations and prelamin A accumulation have been reported in fibroblasts from patients with LMNA mutations and adipocytes exposed to protease inhibitors (PI). As genetically altered lamin A maturation also results in premature ageing syndromes with lipodystrophy, we studied prelamin A expression and senescence markers in cultured human fibroblasts bearing six different LMNA mutations or treated with PIs. As compared to control cells, fibroblasts with LMNA mutations or treated with PIs had nuclear shape abnormalities and reduced proliferative activity that worsened with increasing cellular passages. They exhibited prelamin A accumulation, increased oxidative stress, decreased expression of mitochondrial respiratory chain proteins and premature cellular senescence. Inhibition of prelamin A farnesylation prevented cellular senescence and oxidative stress. Adipose tissue samples from patients with LMNA mutations or treated with PIs also showed retention of prelamin A, overexpression of the cell cycle checkpoint inhibitor p16 and altered mitochondrial markers. Thus, both LMNA mutations and PI treatment result in accumulation of farnesylated prelamin A and oxidative stress that trigger premature cellular senescence. These alterations could participate in the pathophysiology of lipodystrophic syndromes and lead to premature ageing complications.

Comparison of outcomes after transplantation of peripheral blood stem cells versus bone marrow following an identical nonmyeloablative conditioning regimen

This is the first study to examine the outcomes in 54 patients with hematologic malignancies who received an HLA-matched related donor bone marrow (BM, n = 42) or GCSF-mobilized peripheral blood stem cells (PBSC, n = 12) following identical nonmyeloablative conditioning with the intention of induction of mixed chimerism (MC) followed by prophylactic donor leukocyte infusion (pDLI) to convert MC to full donor chimerism (FDC) and capture a graft-versus-tumor effect without clinical graft-versus-host disease (GVHD). Neutrophil and platelet recovery were faster and transfusion requirement was less in PBSC recipients (P < 0.05). A total of 48% of BMT recipients achieved FDC with a median conversion time of 84 days, including 13 following pDLI. In contrast, 83% (P = 0.04) in the PBSC group had spontaneous FDC at a median of 14 days, precluding the administration of pDLI. There was no significant difference in the incidences of acute or chronic GVHD, though the rates of chronic GVHD were considerably higher in PBSC group than in the BM group (6/7, 86% vs 10/24, 42%). CD4 and CD8 T-cell recovery was faster in PBSC recipients. In PBSC recipients, a higher number of CD34+ cells was associated with increased rates of severe, grade III-IV acute GVHD.

[Primary lipodystrophies]

Primary lipodystrophies represent a heterogeneous group of very rare diseases with a prevalence of less than 1 case for 100.000, inherited or acquired, caracterized by a loss of body fat either generalized or localized (lipoatrophy). In some forms, lipoatrophy is associated with a selective hypertrophy of other fat depots. Clinical signs of insulin resistance are often present: acanthosis nigricans, signs of hyperandrogenism. All lipodystrophies are associated with dysmetabolic alterations with insulin resistance, altered glucose tolerance or diabetes and hypertriglyceridemia leading to a risk of acute pancreatitis. Chronic complications are those resulting from diabetes involving the retina, kidney and nerves, cardiovascular complications and steatotic liver lesions that could result in cirrhosis. Genetic forms of generalized lipodystrophy (or Berardinelli-Seip syndrome) result, in most cases, from recessive mutations in one of two genes: either BSCL2 coding seipin or BSCL1 coding AGPAT2, an acyl-transferase involved in triglyceride synthesis. Acquired generalized lipodystrophy (Lawrence syndrome) is of unknown origin but is sometimes associated with signs of autoimmunity. Partial lipodystrophies can be familial with dominant transmission. Heterozygous mutations have been identified in the LMNA gene encoding nuclear lamin A/C belonging to the nuclear lamina, or in PPARG encoding the adipogenic transcription factor PPARgamma. Some less typical lipodystrophies, associated with signs of premature aging, have been linked to mutations in LMNA or in the ZMPSTE24 gene encoding the protease responsible for the maturation of prelamin A into lamin A. Acquired partial lipodystrophy (Barraquer-Simons syndrome) is characterized by cephalothoracic fat loss. Its aetiology is unknown but mutations in LMNB2, encoding the lamina protein lamin B2, could represent susceptibility factors. Highly active antiretroviral treatments for HIV infection are currently the most frequent cause of acquired secondary lipodystrophic syndromes. The genetic diagnosis is performed in specialized laboratories and, in the most severe forms, antenatal diagnosis could be proposed. Treatment of diabetes, dyslipidemia and complications involves the classical intervention strategies. Insulino-sensitizing drugs are useful. Therapeutic trials with recombinant human leptin in patients with very low leptin levels reported good results with respect to the metabolic and liver alterations. The prognosis is linked to the precocity and severity of the diabetic, cardiovascular and liver complications.

Identification of genotype 1 hepatitis E virus in samples from swine in Cambodia

Hepatitis E virus (HEV) is a major enterically transmitted pathogen in many developing countries, where it causes outbreaks and sporadic cases of acute hepatitis. A study conducted with pigs from several livestock farms in Cambodia identified one swine genotype 1 HEV isolate as being associated with prevalent swine genotype 3 HEV.

Long-term treatment with interleukin-1beta induces insulin resistance in murine and human adipocytes

AIMS/HYPOTHESIS

Adipose tissue inflammation has recently been implicated in the pathogenesis of insulin resistance and is probably linked to high local levels of cytokines. IL1B, a proinflammatory cytokine, may participate in this alteration.

MATERIALS AND METHODS

We evaluated the chronic effect (1-10 days) of IL1B (0.1-20 ng/ml) on insulin signalling in differentiating 3T3-F442A and differentiated 3T3-L1 murine adipocytes and in human adipocytes. We also assessed expression of the gene encoding IL1B in adipose tissue of wild-type and insulin-resistant mice (diet-induced and genetically obese ob/ob mice).

RESULTS

IL1B inhibited insulin-induced phosphorylation of the insulin receptor beta subunit, insulin receptor substrate 1, Akt/protein kinase B and extracellular regulated kinase 1/2 in murine and human adipocytes. Accordingly, IL1B suppressed insulin-induced glucose transport and lipogenesis. Long-term treatment of adipose cells with IL1B decreased cellular lipid content. This could result from enhanced lipolysis and/or decreased expression of genes involved in lipid metabolism (acetyl-CoA carboxylase, fatty acid synthase). Down-regulation of peroxisome proliferating-activated receptor gamma and CCAAT/enhancer-binding protein alpha in response to IL1B may have contributed to the altered phenotype of IL1B-treated adipocytes. Moreover, IL1B altered adipocyte differentiation status in long-term cultures. IL1B also decreased the production of adiponectin, an adipocyte-specific protein that plays a positive role in insulin sensitivity. Expression of the gene encoding IL1B was increased in epididymal adipose tissue of obese insulin-resistant mice.

CONCLUSIONS/INTERPRETATION

IL1B is upregulated in adipose tissue of obese and insulin-resistant mouse models and may play an important role in the development of insulin resistance in murine and human adipose cells.

Validation of single real-time TaqMan PCR assay for the detection and quantitation of four major genotypes of hepatitis E virus in clinical specimens

Since the characterization of the genome of the hepatitis E virus (HEV) in 1990, a large genetic diversity has been described. A single real-time reverse transcription (RT)-PCR assay with TaqMan technology has been validated which uses only one set of primers and probe within the ORF2 HEV region (nt 5207-5292) for the detection and quantification of the four major genotypes of HEV. This assay proved to be as efficient as the conventional RT-PCR methodology for the detection of HEV in clinical samples testing positive previously. The real-time RT-PCR and conventional RT-PCR were performed comparatively on 60 pairs of sera and stools collected during a recent outbreak of hepatitis E in Darfur. The real-time RT-PCR assay was 10- to 100-fold sensitive than for conventional RT-PCR assays used in this study with a range quantitation from 1.8 x 10(1) to 7.2 x 10(3) RNA copies/microl in clinical samples (serum and stools).

Diseases of adipose tissue: genetic and acquired lipodystrophies

Human lipodystrophies represent a group of diseases characterized by altered body fat amount and/or repartition and major metabolic alterations with insulin resistance leading to diabetic complications and increased cardiovascular and hepatic risk. Genetic forms of lipodystrophies are rare. Congenital generalized lipodystrophy or Berardinelli-Seip syndrome, autosomal recessive, is characterized by a complete early lipoatrophy and severe insulin resistance and results, in most cases, from mutations either in the seipin gene of unknown function or AGPAT2 encoding an enzyme involved in triacylglycerol synthesis. The Dunnigan syndrome [FPLD2 (familial partial lipodystrophy of the Dunnigan type)] is due to mutations in LMNA encoding the lamin A/C, belonging to the complex group of laminopathies that could comprise muscular and cardiac dystrophies, neuropathies and syndromes of premature aging. Some FPLDs are linked to loss-of-function mutations in the PPAR-gamma gene (peroxisome-proliferator-activated receptor gamma; FPLD3) with severe metabolic alterations but a less severe lipodystrophy compared with FPLD2. The metabolic syndrome, acquired, represents the most common form of lipodystrophy. HIV-infected patients often present lipodystrophies, mainly related to side effects of antiretroviral drugs together with insulin resistance and metabolic alterations. Such syndromes help to understand the mechanisms involved in insulin resistance resulting from altered fat repartition and could benefit from insulin-sensitizing effects of lifestyle modifications or of specific medications.

Proteomic Analysis of Membrane-associated Proteins from the Breast Cancer Cell Line MCF7

BACKGROUND

Proteins associated with cancer cell membranes represent targets of choice for humoral immune response as well as potential tumour marker proteins in human malignancies. However, proteomic analysis of these proteins, and more generally of low-soluble proteins, remains difficult.

MATERIALS AND METHODS

The breast cancer cell line MCF7 was selected to evaluate a sequential extraction method that enables simple fractionation of human cell proteins according to their subcellular localization, yielding subproteomes enriched in cytosolic and membrane-associated proteins, respectively. A crude plasma membrane preparation was followed by the solubilisation of proteins using trifluoroethanol (TFE) as co-solvent.

RESULTS

Cross-matching and statistical analysis performed for each set of two-dimensional electrophoresis (whole-cell, membrane and soluble extracts) and between the different sets highlighted the reproducibility of the extraction process and its usefulness for proteomic analysis. Eighty-three % of the spots of the gels corresponding to the membrane fraction were not found in the gels of the soluble fraction.

CONCLUSION

Due to its simplicity, the approach described here appears well suited for membrane proteomic investigation of human cancer cells and detection of potential biomarkers undetected by current techniques.

Proteomic Study of Galectin-1 Expression in Human Mesenchymal Stem Cells

Bone marrow-derived mesenchymal stem cells (MSCs) are known to interact with hematopoietic stem cells (HSCs) and immune cells, and are of potential interest to be used as therapeutic agents for enhancing allogenic hematopoietic engraftment and preventing graft-versus-host disease (GVHD). Galectin 1 (Gal1) belongs to a family of structurally related molecules expressed in many vertebrate tissues that exert their functions both by binding to glycoconjugates, and by interaction with protein partners. In this work using a proteomic approach, we looked for the presence and the localization of Gal1 in short- and long-term culture of human (h) hMSC. We first determined, that Gal1 is one of the major proteins expressed in hMSC. We futher demonstrated that its expression is maintained when hMSC are expanded through a subculturing process up to five passages. Moreover, Gal1 is secreted and found at the cell surface of MSC, participating in extra cellular matrix (ECM)-cell interactions. Given the immunomodulatory properties of Gal1, its potential involvement in immunological functions of hMSC could be suggested.

Application of metal-chelate affinity chromatography to the study of the phosphoproteome

With the increasing importance of proteome analysis, studying the phosphoproteome is a priority for functional studies. Therefore, a rational approach to simplifying the proteome is needed. In this work, we examined the use of immobilized metal affinity chromatography (IMAC) using ferric ions-chelated column for enriching crude cell extracts in phosphoproteins. The adsorption of the proteins on Fe(3+) was obtained at an acidic pH 5.6, and their elution at a more basic pH in Tris buffer. To evaluate the separation, western blots were performed with either anti-phosphotyrosine or anti-phosphoserine/threonine. The analysis of the eluates demonstrated the selectivity of the separation, particularly for proteins phosphorylated on serine or threonine. In conclusion, the advantages and the limits of this approach are discussed.

The two rotor components of yeast mitochondrial ATP synthase are mechanically coupled by subunit delta

The mitochondrial ATP synthase is made of a membrane-integrated F0 component that forms a proton-permeable pore through the inner membrane and a globular peripheral F1 domain where ATP is synthesized. The catalytic mechanism is thought to involve the rotation of a 10-12 c subunit ring in the F0 together with the gamma subunit of F1. An important and not yet resolved question is to define precisely how the gamma subunit is connected with the c-ring. In this study, using a doxycycline-regulatable expression system, we provide direct evidence that the rest of the enzyme can assemble without the delta subunit of F1, and we show that delta-less mitochondria are uncoupled because of an F0-mediated proton leak. Based on these observations, and taking into account high-resolution structural models, we propose that subunit delta plays a key role in the mechanical coupling of the c-ring to subunit gamma.

[Status of resistance of HIV-1 strains in Africa: what is the role of viral surveillance networks?]

The human immunodeficiency virus (HIV-1) epidemic has spread dramatically in sub-Saharan African countries. Implementation of active antiretroviral (ARV) therapy programs is urgently needed. However this emergency situation must not extenuate the importance of preliminary studies on ARV resistance of African HIV-1 isolates. Findings show that genetic mutations underlying the resistance of African strains are generally identical to those observed in HIV-1 subtype B in industrialized countries. However the incidence of some mutations associated with mild resistance to protease inhibitors (PI) appears higher in African isolates. The potential impact of these mutations for development of frank resistance to PI is still unclear. The incidence of high-grade resistance markers in untreated subjects is low. While these results do not compromise use of ARV therapy in Africa, they underline the need to set up local networks for patient follow-up and to carry out epidemiological surveillance of HIV-1 resistance. Success of ARV therapies in Africa will also depend on economic and social programs.

Cocaine mechanisms: enhanced cocaine, fluoxetine and nisoxetine place preferences following monoamine transporter deletions

Cocaine blocks uptake by neuronal plasma membrane transporters for dopamine, serotonin and norepinephrine, producing subjective effects in humans that are both euphoric/rewarding and also fearful, jittery and aversive. Mice with gene knockouts of each of these transporters display cocaine reward, manifest by cocaine place preferences that are at least as great as wildtype values. Norepinephrine and serotonin receptor knockouts even display enhanced cocaine reward. One explanation for these observations could be that cocaine produces aversive or anhedonic effects by serotonin or norepinephrine receptor blockade in wildtype mice that are removed in serotonin or norepinephrine receptor knockouts, increasing net cocaine reward. Adaptations to removing one transporter could also change the rewarding valence of blocking the remaining transporters. To test these ideas, drugs that block serotonin transporter (fluoxetine), norepinephrine transporter (nisoxetine) or all three transporters (cocaine) were examined in single- or multiple-transporter knockout mice. Fluoxetine and nisoxetine acquire rewarding properties in several knockouts that are not observed in wildtype mice. Adding serotonin transporter knockout to norepinephrine transporter knockouts dramatically potentiates cocaine reward. These and previous data provide evidence that serotonin and norepinephrine transporter blockade can contribute to the net rewarding valence of cocaine. They identify neuroadaptations that may help to explain the retention of cocaine reward by dopamine and serotonin transporter knockout mice. They are consistent with emerging hypotheses that actions at the three primary brain molecular targets for cocaine each provide distinct contributions to cocaine reward and cocaine aversion in wildtype mice, and that this balance changes in mice that develop without dopamine, norepinephrine or serotonin transporters.

[Major insulin resistance syndromes: clinical and physiopathological aspects]

Insulin resistance is a common metabolic disorder. It plays an important role in the metabolic syndrome (or syndrome X), type 2 diabetes, obesity and in the lipodystrophic syndromes recently described, associated with treatments of HIV disease and represent a worrying cardiovascular risk. However, its pathophysiology remains poorly understood in these situations. Syndromes of major insulin resistance, although rare, allow investigations of the mechanisms leading to alterations in the insulin transduction pathways. Mutations of the insulin receptor gene have been discovered in rare patients. Therefore alterations at the post-receptor level are probably causative in other cases. Furthermore, the role of body fat repartition seems determinant in the apparition of insulin resistance, as attested by the clinical characteristics of lipodystrophies, either congenital or acquired. The two lipodystrophic syndromes which molecular defect is identified are the familial partial lipodystrophy of the Dunnigan type, due to mutations of the lamin A/C gene, and the congenital generalized lipodystrophy, linked to alterations in the protein seipin. However, their physiopathology remains mysterious. Lamin A/C is indeed an ubiquitous nuclear protein, which is also mutated in a genetic squelettic and/or cardiac myopathy, and seipin is a protein of unknown function mainly expressed in brain. Progresses in the understanding of these syndromes, in particular lipodystrophies which can be considered as caricatural models of the metabolic syndrome, will probably allow to clarify the physiopathology of the more common forms of insulin resistance.

Two-dimensional database of a Burkitt lymphoma cell line (DG 75) proteins: protein pattern changes following treatment with 5'-azycytidine

Hypermethylation is an important mechanism for repression of tumor gene suppressor in cancer. The drug 5'-azacytidine (AZC) has been used as demethylating agent to induce the expression of previously silencing genes. In the present work, we attempted to determine, using proteomics, the changes in protein expression profiles following a treatment of an Epstein Barr virus (EBV)-negative Burkitt lymphoma (BL) cell line DG 75. The effects of the treatment in terms of cell viability and growth were first examined. The following observations were made: AZC treatment led to (i) a decrease in cell growth with an arrest of the cell at G0/G1 phase of the cell cycle, (ii) the expression of p16, a tumor-suppressor gene whose expression was dependent on its promoter demethylation. Proteomic study evidenced that AZC treatment affected protein expression in two different ways. Twenty-one polypeptides were down-expressed, while 14 showed an increased expression. Some of the upregulated proteins appeared related to the energy metabolism, to organization of cytoskeletal structures, and to cell viability and protein synthesis. We also established a reference map for proteins in DG 75 cell line, comprising 74 different polypeptides corresponding to 67 proteins. This map will be accessible via Internet as a resource for proteome analyses of B-cells. Taken together, the results presented here highlight new insights into lymphoma cell gene regulations following a treatment of lymphoma cells with AZC and illustrate a use of proteomics to evidence the direct and indirect effects of a drug and the pathways it possibly regulates.

The HIV protease inhibitor indinavir impairs sterol regulatory element-binding protein-1 intranuclear localization, inhibits preadipocyte differentiation, and induces insulin resistance

Protease inhibitors used in the treatment of HIV infection have been causally associated with lipodystrophy and insulin resistance and were shown to alter adipocyte differentiation in cultured cells. We aimed to delineate the mechanism by which indinavir impaired adipocyte function. We report that indinavir altered neither the growth nor insulin sensitivity of 3T3-F442A preadipocytes, nor did it alter the initial step of their differentiation, i.e., clonal proliferation. However, adipose conversion was inhibited by indinavir (by 50-60%), as shown by 1) the decrease in the number of newly formed adipocytes; 2) the lower level of the adipogenic protein markers, sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-gamma (PPAR-gamma), and the insulin receptor (IR); and 3) the lack of SREBP-1 and PPAR-gamma immunoreactivity in the nucleus of most indinavir-treated cells. Partial adipose conversion also correlated with an accumulation of SREBP-1 at the nuclear periphery and an alteration in its electrophoretic mobility. Defective expression and nuclear localization of PPAR-gamma probably resulted from the decreased level of nuclear SREBP-1. Indinavir also rendered 3T3-F442A adipocytes resistant to insulin for mitogen-activated protein kinase activation at a step distal to IR substrate-1 tyrosine phosphorylation. Hence, indinavir impairs differentiation at an early step of adipose conversion probably involving the process controlling SREBP-1 intranuclear localization.

Two-dimensional database of a Burkitt lymphoma cell line (DG 75) proteins: protein pattern changes following treatment with 5'-azycytidine

Hypermethylation is an important mechanism for repression of tumor gene suppressor in cancer. The drug 5'-azacytidine (AZC) has been used as demethylating agent to induce the expression of previously silencing genes. In the present work, we attempted to determine, using proteomics, the changes in protein expression profiles following a treatment of an Epstein Barr virus (EBV)-negative Burkitt lymphoma (BL) cell line DG 75. The effects of the treatment in terms of cell viability and growth were first examined. The following observations were made: AZC treatment led to (i) a decrease in cell growth with an arrest of the cell at G0/G1 phase of the cell cycle, (ii) the expression of p16, a tumor-suppressor gene whose expression was dependent on its promoter demethylation. Proteomic study evidenced that AZC treatment affected protein expression in two different ways. Twenty-one polypeptides were down-expressed, while 14 showed an increased expression. Some of the upregulated proteins appeared related to the energy metabolism, to organization of cytoskeletal structures, and to cell viability and protein synthesis. We also established a reference map for proteins in DG 75 cell line, comprising 74 different polypeptides corresponding to 67 proteins. This map will be accessible via Internet as a resource for proteome analyses of B-cells. Taken together, the results presented here highlight new insights into lymphoma cell gene regulations following a treatment of lymphoma cells with AZC and illustrate a use of proteomics to evidence the direct and indirect effects of a drug and the pathways it possibly regulates.

The BPP (protein biochemistry and proteomics) two-dimensional electrophoresis database

The BPP (protein biochemistry and proteomics) two-dimensional electrophoresis (2-DE) database (http://www-smbh.univ-paris13.fr/lbtp/Biochemistry/Biochimie/bque.htm) was established in 1998. The current release contains 11 reference maps from human hematopoietic and lymphoid cell line samples. These reference maps have now 255 identified spots, corresponding to 84 protein entries. The World Wide Web (WWW) presentation is designed to allow public access to the available 2-DE data together with logical connections to databases providing complementary information.

Activation of the growth plates on three-phase bone scintigraphy: the explanation for the overgrowth of fractured femurs

Children with an uncomplicated femoral fracture, treated with superimposition of fragments and intentional shortening, usually develop overgrowth of the fractured femur and the ipsilateral tibia which may compensate for the initial shortening and enable the limb in question to reach a length similar to that on the normal side. The overgrowth is evaluated clinically and by scanography. The increased metabolic activity of the growth plates that support this overgrowth has not been documented by any laboratory method. In order to evaluate the metabolic activity of the growth plates, 18 patients (11 males, seven females; mean age 6.1 years) with fractures of the femur were studied at three different time intervals (2-5 months, 6-12 months and 18-24 months). Three-phase bone scintigraphy was performed in all patients. Ten children (five males, five females; mean age 7.5 years) who had had bone imaging for other reasons were used as the control group. Visual analysis of the flow and equilibrium phases was performed for the distal femoral and proximal tibial growth plates. Visual and semi-quantitative analyses of the delayed images were performed for the distal femoral and proximal and distal tibial growth plates. Semi-quantitative analyses yielded the following activity ratios: (a) the distal femoral growth plate of the fractured femur to the contralateral one (FR); (b) the proximal growth plate of the tibia on the side of the fractured femur to the contralateral one (TpR); (c) the distal growth plate of the tibia on the side of the fractured femur to the contralateral one (TdR); and (d) in the control group, the distal growth plates of both femora (FCG) and the proximal (TCGp) and distal (TCGd) growth plates of the tibiae. Visual analysis of the blood flow, equilibrium and delayed images showed increased activity in the distal femoral growth plates during the first and second time intervals, but not during the third. No significant activity changes were found in the proximal and distal tibial growth plates during any of the phases analysed. The mean and standard deviation for FR in the three time intervals were: FRI=1.22+/-0.27, FRII=1.17+/-0.16 and FRIII=1.09+/-0.20. FR values were significantly higher than in the control group (FCG=0.99+/-0.03) (P=0.033). The mean and standard deviation for TpR in the three time intervals were: TpRI=1.08+/-0.18, TpRII=0.94+/-0.09 and TpRIII=0.96+/-0.20. TpR values were not significantly different from those in the control group (TCGp=1.00+/-0.05). However, TpRI was significantly higher than TpRII (P=0.043). The mean and standard deviation for TdR in the three time intervals were: TdRI=1.10+/-0.41, TdRII=1.05+/-0.15 and TdRIII=1.13+/-0.36. TdR values were not significantly higher than in the control group (TCGd=1.00+/-0.04) (P=0.777). These results support the concept that three-phase bone imaging is able to quantify and determine that activation occurs in the distal femoral and proximal tibial growth plates of fractured femora. This phenomenon may explain the overgrowth observed in this injured bone structure.

Protein analysis by mass spectrometry and sequence database searching: a proteomic approach to identify human lymphoblastoid cell line proteins

Lymphoblastoid cell lines correspond to in vitro EBV-immortalized lymphocyte B-cells. These cells display a suitable model for experiments dealing with changes in protein expression occurring upon B-cell differentiation, after drug treatment, or after inhibition of some transcription factors. For all these reasons we have undertaken an effort aimed at developing a hematopoietic cell line protein two-dimensional electrophoresis (2-DE) database, containing B-lymphoblastoid 2-DE maps. In this work, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) peptide mass fingerprinting analysis was adopted for protein identification. The peptide mass fingerprinting identification and the sequence coverage obtained on colloidal Coomassie blue (CBB) stained gel was close to that obtained using zinc-imidazole staining. Everything considered, CBB being more comfortable for subsequent spot manipulations, CBB staining was chosen for identification of a larger number of polypeptides. The results suggest that reticulation of the gel can interfere preventing the uptake of the enzyme during the in-gel digestion step. Consequently, low molecular mass proteins appear more difficult to identify by mass fingerprinting. Finally, the information provided in this study allows the construction of a new annoted reference map of human lymphoblastoid cell proteins. Among the identified proteins 60% were not yet positioned on 2-DE maps in three of the most important well-documented databases. The annoted map will be accessible via Internet on the LBPP server at URL:http:// www-smbh.univ-paris13.fr/lbtp/index.htm.

Effects of ethanol on phosphoinositide hydrolysis and muscarinic acetylcholine receptor number in SH-SY5Y cells

Previous studies suggest that the effects of ethanol on carbachol-stimulated I(1,4,5)P3 formation and on the number of mAChRs may be independent of each other. The aim of this work was to further study this hypothesis. Human neuroblastoma SH-SY5Y cells were used as a model system. Acute exposure of the cells to 100 mM ethanol induced a decrease in [3H]N-methylscopolamine ([3H]NMS) binding at 30 seconds which was of lower magnitude and of shorter duration than the previously described ethanol-induced inhibition of the peak of carbachol-stimulated I(1,4,5)P3 formation. Long-term ethanol treatment of the cells induced a time- and concentration-dependent increase in [3H]NMS binding. Three hours of 100 mM ethanol treatment were sufficient to increase the number of mAChRs at the cell surface but these receptors were not immediately functionally active, suggesting that they may be newly synthesized. Furthermore, the ethanol-induced potentiation of carbachol-stimulated I(1,4,5)P3 formation, after two days, was, for all ethanol concentrations tested, of higher magnitude than the ethanol-induced increase in mAChR number. Together, these data indicate that both acute and chronic ethanol-induced changes in carbachol-stimulated I(1,4,5)P3 formation may not only be explained by changes in mAChR density at the cell surface but may rather be the consequence of actions of ethanol down-stream of the receptor.

Regulation of CD45-induced signaling by galectin-1 in Burkitt lymphoma B cells

It has been well established that Galectin-1 (GAL1), a beta-galactoside-binding protein, regulates the viability of lymphoid cells. However, the signaling pathway governed by the binding of GAL1 to the cell membrane is not understood. As a first step towards the elucidation of GAL1-initiated signaling events leading to a reduced viability of Burkitt lymphoma B cells, we tried to characterize the initial events induced by the binding of GAL1 to its receptor. This characterization was performed in BL36 cells, a Burkitt lymphoma cell line sensitive to GAL1. The results were as follows: (1) when solubilized cell membrane lysates were affinity bound to immobilized GAL1 and eluted by competition, the tyrosine phosphatase glyco-protein CD45 was found in the eluate, highlighting the role of CD45 as a receptor of GAL1; (2) the phosphatase activity of cell membranes diminished after incubation with GAL1; (3) immunoprecipitation experiments demonstrated that the phosphotyrosine kinase Lyn was dysregulated in cells that have been cultured in medium containing 700 nM GAL1, and (4) that the ratio between two isoforms of Lyn was modified during the treatment with GAL1. The regulation of Lyn therefore seems to be a key event in the action of GAL1.