Brown and beige adipose tissue regulate systemic metabolism through a metabolite interorgan signaling axis

Brown and beige adipose tissue are emerging as distinct endocrine organs. These tissues are functionally associated with skeletal muscle, adipose tissue metabolism and systemic energy expenditure, suggesting an interorgan signaling network. Using metabolomics, we identify 3-methyl-2-oxovaleric acid, 5-oxoproline, and β-hydroxyisobutyric acid as small molecule metabokines synthesized in browning adipocytes and secreted via monocarboxylate transporters. 3-methyl-2-oxovaleric acid, 5-oxoproline and β-hydroxyisobutyric acid induce a brown adipocyte-specific phenotype in white adipocytes and mitochondrial oxidative energy metabolism in skeletal myocytes both in vitro and in vivo. 3-methyl-2-oxovaleric acid and 5-oxoproline signal through cAMP-PKA-p38 MAPK and β-hydroxyisobutyric acid via mTOR. In humans, plasma and adipose tissue 3-methyl-2-oxovaleric acid, 5-oxoproline and β-hydroxyisobutyric acid concentrations correlate with markers of adipose browning and inversely associate with body mass index. These metabolites reduce adiposity, increase energy expenditure and improve glucose and insulin homeostasis in mouse models of obesity and diabetes. Our findings identify beige adipose-brown adipose-muscle physiological metabokine crosstalk.

Design and Efficacy of a Monovalent Bispecific PD-1/CTLA4 Antibody That Enhances CTLA4 Blockade on PD-1+ Activated T Cells

The clinical benefit of PD-1 blockade can be improved by combination with CTLA4 inhibition but is commensurate with significant immune-related adverse events suboptimally limiting the doses of anti-CTLA4 mAb that can be used. MEDI5752 is a monovalent bispecific antibody designed to suppress the PD-1 pathway and provide modulated CTLA4 inhibition favoring enhanced blockade on PD-1⁺ activated T cells. We show that MEDI5752 preferentially saturates CTLA4 on PD-1⁺ T cells versus PD-1^- T cells, reducing the dose required to elicit IL2 secretion. Unlike conventional PD-1/CTLA4 mAbs, MEDI5752 leads to the rapid internalization and degradation of PD-1. Moreover, we show that MEDI5752 preferentially localizes and accumulates in tumors providing enhanced activity when compared with a combination of mAbs targeting PD-1 and CTLA4 in vivo. Following treatment with MEDI5752, robust partial responses were observed in two patients with advanced solid tumors. MEDI5752 represents a novel immunotherapy engineered to preferentially inhibit CTLA4 on PD-1⁺ T cells. SIGNIFICANCE: The unique characteristics of MEDI5752 represent a novel immunotherapy engineered to direct CTLA4 inhibition to PD-1⁺ T cells with the potential for differentiated activity when compared with current conventional mAb combination strategies targeting PD-1 and CTLA4. This molecule therefore represents a step forward in the rational design of cancer immunotherapy.See related commentary by Burton and Tawbi, p. 1008.This article is highlighted in the In This Issue feature, p. 995.

In vitro characterization of the effects of chronic insulin stimulation in mouse 3T3-L1 and human SGBS adipocytes

Hyperinsulinemia is the hallmark of the development of insulin resistance and precedes the diagnosis of type 2 diabetes. Here we evaluated the effects of prolonged exposure (≥4 days) to high insulin doses (150 nM) in vitro in two adipose cell types, mouse 3T3-L1 and human SGBS. Chronic insulin treatment significantly decreased lipid droplet size, insulin signalling and insulin-stimulated glucose uptake. 3T3-L1 displayed an increased basal glucose internalization following chronic insulin treatment, which was associated with increased GLUT1 expression. In addition, both cells showed increased basal lipolysis.

In conclusion, we report the effects of prolonged hyperinsulinemia in 3T3-L1 and SGBS, highlighting similarities and discrepancies between the cell types, to be considered when using these cells to model insulin-induced insulin resistance.

Module-based construction of plasmids for chromosomal integration of the fission yeast Schizosaccharomyces pombe

Integration of an external gene into a fission yeast chromosome is useful to investigate the effect of the gene product. An easy way to knock-in a gene construct is use of an integration plasmid, which can be targeted and inserted to a chromosome through homologous recombination. Despite the advantage of integration, construction of integration plasmids is energy- and time-consuming, because there is no systematic library of integration plasmids with various promoters, fluorescent protein tags, terminators and selection markers; therefore, researchers are often forced to make appropriate ones through multiple rounds of cloning procedures. Here, we establish materials and methods to easily construct integration plasmids. We introduce a convenient cloning system based on Golden Gate DNA shuffling, which enables the connection of multiple DNA fragments at once: any kind of promoters and terminators, the gene of interest, in combination with any fluorescent protein tag genes and any selection markers. Each of those DNA fragments, called a ‘module’, can be tandemly ligated in the order we desire in a single reaction, which yields a circular plasmid in a one-step manner. The resulting plasmids can be integrated through standard methods for transformation. Thus, these materials and methods help easy construction of knock-in strains, and this will further increase the value of fission yeast as a model organism.

Wall mechanics and exocytosis define the shape of growth domains in fission yeast

The amazing structural variety of cells is matched only by their functional diversity, and reflects the complex interplay between biochemical and mechanical regulation. How both regulatory layers generate specifically shaped cellular domains is not fully understood. Here, we report how cell growth domains are shaped in fission yeast. Based on quantitative analysis of cell wall expansion and elasticity, we develop a model for how mechanics and cell wall assembly interact and use it to look for factors underpinning growth domain morphogenesis. Surprisingly, we find that neither the global cell shape regulators Cdc42-Scd1-Scd2 nor the major cell wall synthesis regulators Bgs1-Bgs4-Rgf1 are reliable predictors of growth domain geometry. Instead, their geometry can be defined by cell wall mechanics and the cortical localization pattern of the exocytic factors Sec6-Syb1-Exo70. Forceful re-directioning of exocytic vesicle fusion to broader cortical areas induces proportional shape changes to growth domains, demonstrating that both features are causally linked.

Cell shape is determined by a combination of biochemical regulation and mechanical forces. By imaging the dynamic behaviour of growth regulatory proteins in fission yeast and integrating these data within a mechanical model, Abenza et al. find that exocytosis plays a dominant role in shaping growth domains.

A network approach to mixing delegates at meetings

Delegates at scientific meetings can come from diverse backgrounds and use very different methods in their research. Promoting interactions between these ‘distant’ delegates is challenging but such interactions could lead to novel interdisciplinary collaborations and unexpected breakthroughs. We have developed a network-based ‘speed dating’ approach that allows us to initiate such distant interactions by pairing every delegate with another delegate who might be of interest to them, but whom they might never have encountered otherwise. Here we describe our approach and its algorithmic implementation.

Spatial segregation of polarity factors into distinct cortical clusters is required for cell polarity control

Cell polarity is regulated by evolutionarily conserved polarity factors whose precise higher-order organization at the cell cortex is largely unknown. Here we image frontally the cortex of live fission yeast cells using time-lapse and super-resolution microscopy. Interestingly, we find that polarity factors are organized in discrete cortical clusters resolvable to ~50–100 nm in size, which can form and become cortically enriched by oligomerization. We show that forced co-localization of the polarity factors Tea1 and Tea3 results in polarity defects, suggesting that the maintenance of both factors in distinct clusters is required for polarity. However, during mitosis, their co-localization increases, and Tea3 helps to retain the cortical localization of the Tea1 growth landmark in preparation for growth reactivation following mitosis. Thus, regulated spatial segregation of polarity factor clusters provides a means to spatio-temporally control cell polarity at the cell cortex. We observe similar clusters in Saccharomyces cerevisiae and Caenorhabditis elegans cells, indicating this could be a universal regulatory feature.

Cell polarity is generated and maintained by the spatial accumulation of polarity factors. By imaging fission yeast cells ‘end-on’, the authors show that the polarity factors Tea1 and Tea3 segregate into distinct clusters, and that surprisingly, their segregation is critical for cell polarization.

The role and aims of the FYSSION project

FYSSION is a resource for researchers working on the fission yeast Schizosaccharomyces pombe. It currently comprises libraries of temperature-sensitive mutants in essential genes, and insertional mutants in non-essential genes, available for screening by visiting workers. Here we outline methods for constructing and using the libraries, and describe future prospects for functional genomics of this organism, here and elsewhere.

Direct evidence of host genome acquisition by the alphaherpesvirus Marek’s disease virus

Many herpesviruses including Marek's disease virus (MDV), a poultry alphaherpesvirus, carry homologous host genes presumably acquired during viral evolution. We have characterized one recent acquisition by MDV in considerable detail. The virulent MDV strain Md11 previously was isolated from a commercial chicken and initially propagated on duck cells. In the process of cloning the entire Md11 genome in a bacterial artificial chromosome (BAC), we obtained an infectious clone in which the entire terminal repeat short segment was replaced with a portion of the duck genome that corresponds to chicken chromosome 19. This sequence is not predicted to express any protein even though it contains one exon of the VAMP1 gene. The replacement did not affect MDV replication in vitro, despite the virus having only one copy of ICP4. Furthermore, we have shown that the variant MDV genome containing the duck genome substitution is present in the parental Md11 population and has been maintained through several subsequent propagations of the virus on chicken cells. This finding provides direct evidence that host genome acquisition by MDV actually occurs during virus replication, and that one or more such MDV genomes with host sequences may exist within MDV viral stocks which tend to be polyclonal, due to the cell-associated nature of its infection process.

Tests for the replication of an association between Egfr and natural variation in Drosophila melanogaster wing morphology

Background

Quantitative differences between individuals stem from a combination of genetic and environmental factors, with the heritable variation being shaped by evolutionary forces. Drosophila wing shape has emerged as an attractive system for genetic dissection of multi-dimensional traits. We utilize several experimental genetic methods to validation of the contribution of several polymorphisms in the Epidermal growth factor receptor (Egfr) gene to wing shape and size, that were previously mapped in populations of Drosophila melanogaster from North Carolina (NC) and California (CA). This re-evaluation utilized different genetic testcrosses to generate heterozygous individuals with a variety of genetic backgrounds as well as sampling of new alleles from Kenyan stocks.

Results

Only one variant, in the Egfr promoter, had replicable effects in all new experiments. However, expanded genotyping of the initial sample of inbred lines rendered the association non-significant in the CA population, while it persisted in the NC sample, suggesting population specific modification of the quantitative trait nucleotide QTN effect.

Conclusion

Dissection of quantitative trait variation to the nucleotide level can identify sites with replicable effects as small as one percent of the segregating genetic variation. However, the testcross approach to validate QTNs is both labor intensive and time-consuming, and is probably less useful than resampling of large independent sets of outbred individuals.

A consensus linkage map of the chicken genome

A consensus linkage map has been developed in the chicken that combines all of the genotyping data from the three available chicken mapping populations. Genotyping data were contributed by the laboratories that have been using the East Lansing and Compton reference populations and from the Animal Breeding and Genetics Group of the Wageningen University using the Wageningen/Euribrid population. The resulting linkage map of the chicken genome contains 1889 loci. A framework map is presented that contains 480 loci ordered on 50 linkage groups. Framework loci are defined as loci whose order relative to one another is supported by odds greater then 3. The possible positions of the remaining 1409 loci are indicated relative to these framework loci. The total map spans 3800 cM, which is considerably larger than previous estimates for the chicken genome. Furthermore, although the physical size of the chicken genome is threefold smaller then that of mammals, its genetic map is comparable in size to that of most mammals. The map contains 350 markers within expressed sequences, 235 of which represent identified genes or sequences that have significant sequence identity to known genes. This improves the contribution of the chicken linkage map to comparative gene mapping considerably and clearly shows the conservation of large syntenic regions between the human and chicken genomes. The compact physical size of the chicken genome, combined with the large size of its genetic map and the observed degree of conserved synteny, makes the chicken a valuable model organism in the genomics as well as the postgenomics era. The linkage maps, the two-point lod scores, and additional information about the loci are available at web sites in Wageningen (http://www.zod.wau.nl/vf/ research/chicken/frame_chicken.html) and East Lansing (http://poultry.mph.msu.edu/).

Factors associated with very early weaning among primiparas intending to breastfeed

OBJECTIVES

The major objective of this study was to identify predictor variables that accurately differentiated breastfeeding women who weaned during the first 4 weeks, those who weaned between 5 and 26 weeks, and those who weaned after 26 weeks. Predictors were demographic variables, Theory of Planned Behavior (TPB) variables, breastfeeding knowledge, and difficulties experienced during the first month.

METHODS

Primiparas who delivered healthy infants in an urban midwestern hospital provided initial data prior to discharge. Follow-up occurred at 1, 3, 6, 9, and 12 months. Following appropriate bivariate analyses, polychotomous logistic regression was used to determine predictors of weaning group. Linear multiple regression was used to predict intended duration.

RESULTS

Most of the 84 women who weaned very early had intended to breastfeed considerably longer. According to the multivariate analysis, women who weaned earlier were younger, had completed fewer years of education, had a more positive bottle-feeding attitude and a less positive breastfeeding attitude, intended to breastfeed less time, had lower knowledge scores, had higher perceived insufficient milk scores, and planned to work outside the home. Variables postulated by the TPB to be direct predictors of intention explained 36% of the variance in intended duration.

CONCLUSIONS

Women at risk for early weaning can be identified with reasonable accuracy using a TPB-based conceptual framework expanded to include breastfeeding specific variables. Casefinding using empirically derived screening methods and careful postpartum follow-up, along with professional intervention, should be used to avert unintended early weaning.

A review of caesarean sections at 30 weeks gestation or less in the west of Scotland 1988-1989

A retrospective study was carried out of caesarean sections at 30 completed weeks of gestation or less between 1/1/88 and 31/12/89 in Glasgow and The West of Scotland. One hundred and thirty-three caesarean sections were carried out resulting in 150 babies. Fifteen (11.3%) of these were classical sections. There were 30 neonatal deaths. The perinatal mortality rate was 170 per 1000. Survival was related to increasing gestation from 27 weeks onwards and also to birthweight from 900 grams onwards. In-utero transfers fared badly with seven out of 21 babies (33%) failing to survive beyond the neonatal period. Although survival continues to improve in newborns, the use of caesarean section should still be viewed with caution as the benefits in the very premature situation with regard to infant survival may be outweighed by the increased maternal morbidity both in the present pregnancy and future pregnancies.

v-erbA overexpression is required to extinguish c-erbA function in erythroid cell differentiation and regulation of the erbA target gene CAII

The v-erbA oncoprotein represents a retrovirus-transduced oncogenic version of the thyroid hormone (T3/T4) receptor c-erbA (type alpha). It contributes to virus-induced erythroleukemia by efficiently arresting differentiation of red cell progenitors and by suppressing transcription of erythrocyte-specific genes. Here, we show that v-erbA and c-erbA bind directly to sequences within the promoter of the erythrocyte-specific carbonic anhydrase II (CAII), a gene whose transcription is efficiently suppressed by v-erbA. This erbA-binding site confers thyroid hormone responsiveness to a heterologous promoter in transient expression experiments and is a target for efficient down-regulation of CAII transcription by the v-erbA oncoprotein. In stably transformed erythroblasts coexpressing the v-erbA oncoprotein and the c-erbA/T3 receptor at an approximately equimolar ratio, c-erbA activity is dominant over v-erbA. T3 efficiently induced erythroid differentiation in these cells, thus overcoming the v-erbA-mediated differentiation arrest. Likewise, T3 activated CAII transcription as well as transient expression of a T3-responsive reporter gene containing the CAII-specific erbA-binding site. The c-erbA-dependent activation of this CAII reporter construct could only be suppressed by very high amounts of v-erbA. Our results suggest that overexpression of v-erbA is required for its function as an oncoprotein.

The increasing problem in Tayside of cervical cancer in younger women

The incidence of cervical carcinoma in younger women is increasing in Tayside despite a decrease in the overall incidence. However, stage for stage, we did not encounter a poorer survival in younger patients. A number of patients had been sterilised or had a pregnancy when cytological screening was available and not made use of. There were also some false negative smears which were reclassified for retrospective analysis. We would recommend cervical screening every three years and careful inspection of the cervix and a smear taken in cases of abnormal gynaecological symptoms such as post coital bleeding.

Risk factors in the development of cervical intraepithelial neoplasia in women with vulval warts

Of 59 women referred with vulval warts whose cervices were assessed colposcopically for the presence of cervical intraepithelial neoplasia (CIN) before local treatment of the wart lesions, 17 had histologically proved CIN, 12 had histologically proved cervical wart virus infection, and 30 had abnormality on colposcopy or cytology. Seven of the 17 with CIN had no abnormality on cervical cytology. No differences in sexual behaviour, smoking habit, or oral contraceptive use were seen between women with CIN and those with no cervical abnormality. Viral DNA typing of the vulval lesions was carried out, but there were no differences in the distribution of viral types between the three different histological groups. Of the 30 women with no abnormality at the initial visit, 23 were followed up colposcopically and cytologically for one to two years. Three of them developed CIN after adequate treatment of the vulval lesions despite the absence of cervical abnormalities on colposcopy at the time of treatment. Studying the known factors linked with CIN failed to show why some women with vulval warts develop CIN, even after treatment of the warts, and others do not. The large number of false negative results on cervical cytology in our patients suggests that women presenting with vulval warts should be screened colposcopically in the first instance. Close follow up of women whose warts are treated and who are thought to have no cervical abnormality at that assessment is essential.

Severe pregnancy-induced hypertension: postpartum care of the critically ill patient

SPIH is a disease of unknown cause that contributes to maternal and neonatal morbidity and mortality rates. Familiarity with the normal physiologic adaptations of pregnancy and the confounding pathologic changes of SPIH will enable the health care professional to better understand the principles of management. Immediate therapeutic interventions are necessary to reverse hypertension and to prevent the life-threatening sequelae that may arise from this condition. Postpartum management is directed toward decreasing vasospasm and central nervous system irritability and maintaining fluid and electrolyte balance. Attention must be given to the special obstetric needs of these patients.

Does mild atypia on a cervical smear warrant further investigation?

228 women referred to a colposcopy clinic over a 10-year period with mildly atypical cervical cytology had a histological diagnosis established by colposcopically directed biopsy. Of the 187 women (82.0%) who had dyskaryosis on the referral smear, 129 (69%) had cervical intraepithelial neoplasia (CIN) grade II or III on histology, as did 12 (29.2%) of the 41 women without dyskaryosis. 27.6% of smears taken at the time of colposcopy had normal cytology, although a third of these women had CIN II or III diagnosed on histology at that time. The poor correlation between mildly atypical cervical cytology and histology suggests that the practice of relying on cytology alone for the surveillance of women who have already had an atypical smear should be discouraged.

Updating lung cancer mortality among a cohort of man-made mineral fibre production workers in seven European countries

A historical cohort of 21,967 workers ever employed in 13 European factories manufacturing various types of man-made mineral fibres (MMMF) was observed until 1982. Overall there were 2719 deaths (standardised mortality ratio (SMR) = 111) of which 189 were from lung cancer (SMR = 125). For the glasswool and rockwool/slagwool production subcohorts the lung cancer SMRs rose with time since first exposure, exceeding 170 for the period of 30 or more years. Adjustment for regional variations in mortality substantially reduced the excess in the glasswool group, but not in the rockwool/slagwool. In neither subgroup was there any relationship of lung cancer mortality with length of employment. During the early years of rockwool/slagwool production there was the potential for much higher fibrous dust exposure than at present, because of the absence of dust suppressing oil and/or the use of a batch production process. In addition slag was widely used as a raw material. Amongst workers employed during the early phase, there were 10 lung cancer deaths giving SMRs of 270 and 244 for the periods 20-29 and 30 or more years since first exposure. This group accounts for most of the absolute excess of lung cancer for the rockwool/slagwool plants.

Exposure to oxides of nitrogen: respiratory symptoms and lung function in British coalminers

Five hundred and sixty British coalminers with relatively high or relatively low exposures to oxides of nitrogen, based on measurements of concentrations of these gases at nine collieries over four years, and records of the men's places of work and colliery mining conditions over a total of eight years have been studied. Data on these men's respiratory symptoms and ventilatory capacity (FEV1), obtained as part of an epidemiological study of British coalminers, have been used to investigate possible adverse effects of exposure to oxides of nitrogen. Exposures to oxides of nitrogen were generally well below threshold limit values, though occasional peaks after shotfiring and during diesel locomotive use did exceed short term limits. No relationship was found between exposure and respiratory symptoms or decline in FEV1 nor was there any evidence of differences in symptoms of FEV1 between 44 pairs of men matched for age, dust exposure, smoking habit, coal rank, and type of work, but differing in respect of exposure to oxides of nitrogen. It has not been possible to detect any adverse effects on the health of this working population of the levels of nitrogen oxides that have occurred in British mines over the past decade. With the current levels of these gases, any long term effects on respiratory health are so small as to be undetectable in the presence of smoking and dust exposure.

Coalworkers' simple pneumoconiosis and exposure to dust at 10 British coalmines

Five physicians' radiological assessments of coalworkers' simple pneumoconiosis (CWP) in 2600 coalminers at 10 British collieries have been studied in relation to the individuals' estimated lifetime (mean 33 years) exposure to respirable coalmine dust. Estimates of exposure were based on 20 years of observations at each colliery. Radiographic classifications were clearly associated with the measures of dust exposure. Important unexplained differences between some of the collieries were disclosed. Among men with similar cumulative dust exposures those with longer exposure time had higher prevalence of CWP. In general there was no evidence that the quartz concentrations experienced (average 5% of mixed dust) affected the probability of developing coalworkers' simple pneumoconiosis. Some men reacted unfavourably (two or more steps of change on the 12-point radiological scale) over a 10-year period to coalmine dust with a relatively high quartz content.

Quartz and pneumoconiosis in coalminers

In a routine survey of 623 miners in one colliery, 21 men, an unusually high number, showed radiological progression of simple pneumoconiosis in spite of generally low exposures to mixed coalmine dust. Comparison of the dust exposures of the 21 men with those of matched controls without pneumoconiosis showed highly significant differences in the proportion of quartz in the mixed dust to which they had been exposed. Quartz exposure may be an important factor in the development and rapid progression of coalworkers' pneumoconiosis. Some indication of the levels of quartz exposure which are likely to be hazardous is given.

The evolution of genes: the chicken preproinsulin gene

We have characterized a clone carrying a chicken preproinsulin gene, which is present in only one copy in the chicken genome. The gene contains two introns: a 3.5 kb intron interrupting the region encoding the connecting peptide and a 119 bp intron interrupting the DNA corresponding to the 5' non-coding region of the mRNA. This is similar to the structure of rat insulin gene II; therefore it represents the common ancestor. Since the rat insulin gene I lacks a 499 bp intron in the coding region, the rat genes have evolved by a recent gene duplication followed by loss of this intron in one copy. The divergences between insulin gene sequences, and also between globin genes, show that changes at introns and silent positions in coding regions appear very rapidly (7 X 10(-9) substitutions per nucleotide site per year), but that the accumulation of changes in these sites saturates, although not completely, after about 100 million years. From this we conclude that not all of these sites are neutral and that they do not behave as accurate evolutionary clocks over long periods of time. However, nucleotide substitutions leading to amino acid replacements are an excellent clock. Our analysis indicates that this clock is driven by selection.