Granzyme F: Exhaustion Marker and Modulator of Chimeric Antigen Receptor T Cell-Mediated Cytotoxicity

Granzymes are a family of proteases used by CD8 T cells to mediate cytotoxicity and other less-defined activities. The substrate and mechanism of action of many granzymes are unknown, although they diverge among the family members. In this study, we show that mouse CD8+ tumor-infiltrating lymphocytes (TILs) express a unique array of granzymes relative to CD8 T cells outside the tumor microenvironment in multiple tumor models. Granzyme F was one of the most highly upregulated genes in TILs and was exclusively detected in PD1/TIM3 double-positive CD8 TILs. To determine the function of granzyme F and to improve the cytotoxic response to leukemia, we constructed chimeric Ag receptor T cells to overexpress a single granzyme, granzyme F or the better-characterized granzyme A or B. Using these doubly recombinant T cells, we demonstrated that granzyme F expression improved T cell-mediated cytotoxicity against target leukemia cells and induced a form of cell death other than chimeric Ag receptor T cells expressing only endogenous granzymes or exogenous granzyme A or B. However, increasing expression of granzyme F also had a detrimental impact on the viability of the host T cells, decreasing their persistence in circulation in vivo. These results suggest a unique role for granzyme F as a marker of terminally differentiated CD8 T cells with increased cytotoxicity, but also increased self-directed cytotoxicity, suggesting a potential mechanism for the end of the terminal exhaustion pathway.

Myelodysplastic neoplasm-associated U2AF1 mutations induce host defense defects by compromising neutrophil chemotaxis

Myelodysplastic neoplasm (MDS) is a hematopoietic stem cell disorder that may evolve into acute myeloid leukemia. Fatal infection is among the most common cause of death in MDS patients, likely due to myeloid cell cytopenia and dysfunction in these patients. Mutations in genes that encode components of the spliceosome represent the most common class of somatically acquired mutations in MDS patients. To determine the molecular underpinnings of the host defense defects in MDS patients, we investigated the MDS-associated spliceosome mutation U2AF1-S34F using a transgenic mouse model that expresses this mutant gene. We found that U2AF1-S34F causes a profound host defense defect in these mice, likely by inducing a significant neutrophil chemotaxis defect. Studies in human neutrophils suggest that this effect of U2AF1-S34F likely extends to MDS patients as well. RNA-seq analysis suggests that the expression of multiple genes that mediate cell migration are affected by this spliceosome mutation and therefore are likely drivers of this neutrophil dysfunction.

Transcriptome analysis reveals differences in cell cycle, growth and migration related genes that distinguish fibroblasts derived from pre-invasive and invasive breast cancer

Background/Introduction

As the most common form of pre-invasive breast cancer, ductal carcinoma in situ (DCIS) affects over 50,000 women in the US annually. Despite standardized treatment involving lumpectomy and radiation therapy, up to 25% of patients with DCIS experience disease recurrence often with invasive ductal carcinoma (IDC), indicating that a subset of patients may be under-treated. As most DCIS cases will not progress to invasion, many patients may experience over-treatment. By understanding the underlying processes associated with DCIS to IDC progression, we can identify new biomarkers to determine which DCIS cases may become invasive and improve treatment for patients. Accumulation of fibroblasts in IDC is associated with disease progression and reduced survival. While fibroblasts have been detected in DCIS, little is understood about their role in DCIS progression.

Goals

We sought to determine 1) whether DCIS fibroblasts were similar or distinct from normal and IDC fibroblasts at the transcriptome level, and 2) the contributions of DCIS fibroblasts to breast cancer progression.

Methods

Fibroblasts underwent transcriptome profiling and pathway analysis. Significant DCIS fibroblast-associated genes were further analyzed in existing breast cancer mRNA databases and through tissue array immunostaining. Using the sub-renal capsule graft model, fibroblasts from normal breast, DCIS and IDC tissues were co-transplanted with DCIS.com breast cancer cells.

Results

Through transcriptome profiling, we found that DCIS fibroblasts were characterized by unique alterations in cell cycle and motility related genes such as PKMYT1, TGF-α, SFRP1 and SFRP2, which predicted increased cell growth and invasion by Ingenuity Pathway Analysis. Immunostaining analysis revealed corresponding increases in expression of stromal derived PKMYT1, TGF-α and corresponding decreases in expression of SFRP1 and SFRP2 in DCIS and IDC tissues. Grafting studies in mice revealed that DCIS fibroblasts enhanced breast cancer growth and invasion associated with arginase-1+ cell recruitment.

Conclusion

DCIS fibroblasts are phenotypically distinct from normal breast and IDC fibroblasts, and play an important role in breast cancer growth, invasion, and recruitment of myeloid cells. These studies provide novel insight into the role of DCIS fibroblasts in breast cancer progression and identify some key biomarkers associated with DCIS progression to IDC, with important clinical implications.

Low TCR binding strength results in increased progenitor-like CD8+ tumor-infiltrating lymphocytes

T cell receptor (TCR) binding strength to peptide-MHC antigen complex influences numerous T cell functions. However, the vast diversity of a polyclonal T cell repertoire for even a single antigen greatly increases the complexity of studying the impact TCR affinity has on T cell function. Here, we determined how TCR binding strength affected the protein and transcriptional profile of an endogenous, polyclonal T cell response to a known tumor-associated antigen (TAA) within the tumor microenvironment (TME). We confirmed that flow and CITE-Seq counts of MHC-tetramer labeling were reliable surrogates for the TCR-peptide-MHC steady-state binding affinity. We further demonstrated by single-cell RNA sequencing that tumor-infiltrating lymphocytes (TILs) with high and low binding affinity for a TAA can differentiate into cells with many antigen-specific transcriptional profiles within an established TME. However, more progenitor-like phenotypes were significantly biased towards lower affinity T cells, and proliferating phenotypes showed significant bias towards high-affinity TILs. Additionally, we found in a progressing TME that higher affinity T cells advanced more rapidly to terminal phases of T cell exhaustion and exhibited better tumor control. We confirmed the polyclonal TIL results using a TCR transgenic mouse possessing a single low-affinity TCR targeting the same TAA. These T cells maintained a progenitor-exhausted phenotype and exhibited impaired tumor control. We propose that high-affinity TCR interactions drive T cell fate decisions more rapidly than low-affinity interactions and that these cells differentiate faster. These findings illustrate divergent forms of T cell dysfunction based on TCR affinity which may impact TIL therapies and antitumor responses.

Mapping Macrophage Polarization and Origin during the Progression of the Foreign Body Response to a Poly(ethylene glycol) Hydrogel Implant

Poly(ethylene glycol) (PEG) hydrogels hold promise for in vivo applications but induce a foreign body response (FBR). While macrophages are key in the FBR, many questions remain. This study investigates temporal changes in the transcriptome of implant-associated monocytes and macrophages. Proinflammatory pathways are upregulated in monocytes compared to control monocytes but subside by day 28. Macrophages are initially proinflammatory but shift to a profibrotic state by day 14, coinciding with fibrous capsule emergence. Next, this study assesses the origin of macrophages responsible for fibrous encapsulation using wildtype, C-C Motif Chemokine Receptor 2 (CCR2)^-/- mice that lack recruited macrophages, and Macrophage Fas-Induced Apoptosis (MaFIA) mice that enable macrophage ablation. Subpopulations of recruited and tissue-resident macrophages are identified. Fibrous encapsulation proceeds in CCR2^-/- mice similar to wildtype mice. However, studies in MaFIA mice indicate that macrophages are necessary for fibrous capsule formation. These findings suggest that macrophage origin impacts the FBR progression and provides evidence that tissue-resident macrophages and not the recruited macrophages may drive fibrosis in the FBR to PEG hydrogels. This study demonstrates that implant-associated monocytes and macrophages have temporally distinct transcriptomes in the FBR and that profibrotic pathways associated with macrophages may be enriched in tissue-resident macrophages.

Granzyme F production by CD8 T cells in the tumor microenvironment

Granzymes are a class of cytotoxic proteases and are the primary mechanism utilized by T cells to directly eliminate cancer cells. Each granzyme acts upon a unique set of substrates in target cells to induce cytotoxicity through a range of different mechanisms. Granzymes are some of the most differentially regulated genes in CD8+ tumor infiltrating lymphocytes, relative to T cells outside of the tumor microenvironment (TME). We and others have determined by microarray and qPCR that granzyme F is highly upregulated in the TME. Granzyme F expression is restricted to a small subset of antigen-experienced and exhausted T cells, as determined by flow cytometry-based detection of granzyme F RNA transcripts and may represent a marker of a unique T cell cytotoxic function. Single cell RNA sequencing of CD8 TIL has revealed that granzyme F-high expressing cells are unique from both granzyme A and B expressing cells, and that it is therefore likely these TIL utilize a unique mechanism of cytotoxicity in their elimination of cancer cells. Recombinant granzyme F has previously been shown to induce a unique form of cell death, characterized as being caspase-independent and resulting in rupture of target cell plasma membrane. By over expressing granzyme F we are determining if this mechanism of cell death is leverageable to improve the cytotoxic capacity of TIL, and if induction of different forms of T cell-mediated cytotoxicity can modulate the immunogenicity of the TME. These experiments are designed to provide insight into how to improve adoptive T cell therapies by directly improving cytotoxicity, the terminal step of T cell interaction with tumor cells.

This work was supported by the National Institutes of Health  NIAID training grant (Training Program in Immunology; T32-AI07405) award to Zachary Hay

CFTR-mediated monocyte/macrophage dysfunction revealed by cystic fibrosis proband-parent comparisons

Cystic fibrosis (CF) is an inherited disorder caused by biallelic mutations of the CF transmembrane conductance regulator (CFTR) gene. Converging evidence suggests that CF carriers with only 1 defective CFTR copy are at increased risk for CF-related conditions and pulmonary infections, but the molecular mechanisms underpinning this effect remain unknown. We performed transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) of CF child-parent trios (proband, father, and mother) and healthy control (HC) PBMCs or THP-1 cells incubated with the plasma of these participants. Transcriptomic analyses revealed suppression of cytokine-enriched immune-related genes (IL-1β, CXCL8, CREM), implicating lipopolysaccharide tolerance in innate immune cells (monocytes) of CF probands and their parents. These data suggest that a homozygous as well as a heterozygous CFTR mutation can modulate the immune/inflammatory system. This conclusion is further supported by the finding of lower numbers of circulating monocytes in CF probands and their parents, compared with HCs, and the abundance of mononuclear phagocyte subsets, which correlated with Pseudomonas aeruginosa infection, lung disease severity, and CF progression in the probands. This study provides insight into demonstrated CFTR-related innate immune dysfunction in individuals with CF and carriers of a CFTR mutation that may serve as a target for personalized therapy.

Chromodomain helicase DNA-binding 4 (CHD4) regulates early B cell identity and V(D)J recombination

B lymphocytes develop from uncommitted precursors into immunoglobulin (antibody)-producing B cells, a major arm of adaptive immunity. Progression of early progenitors to antibody-expressing cells in the bone marrow is orchestrated by the temporal regulation of different gene programs at discrete developmental stages. A major question concerns how B cells control the accessibility of these genes to transcription factors. Research has implicated nucleosome remodeling ATPases as mediators of chromatin accessibility. Here, we describe studies of chromodomain helicase DNA-binding 4 (CHD4; also known as Mi-2β) in early B cell development. CHD4 comprises multiple domains that function in nucleosome mobilization and histone binding. CHD4 is a key component of Nucleosome Remodeling and Deacetylase, or NuRD (Mi-2) complexes, which assemble with other proteins that mediate transcriptional repression. We review data demonstrating that CHD4 is necessary for B lineage identity: early B lineage progression, proliferation in response to interleukin-7, responses to DNA damage, and cell survival in vivo. CHD4-NuRD is also required for the Ig heavy-chain repertoire by promoting utilization of distal variable (V_H ) gene segments in V(D)J recombination. In conclusion, the regulation of chromatin accessibility by CHD4 is essential for production of antibodies by B cells, which in turn mediate humoral immune responses to pathogens and disease.

The molecular and epigenetic mechanisms of innate lymphoid cell (ILC) memory and its relevance for asthma

Repetitive exposure of Rag1^−/− mice to the Alternaria allergen extract generated a form of memory that elicited an asthma-like response upon a subthreshold recall challenge 3–15 wk later. This memory was associated with lung ICOS⁺ST2⁺ ILC2s. Genetic, pharmacologic, and antibody-mediated inhibition and adoptive transfer established an essential role for ILC2s in memory-driven asthma. ATAC-seq demonstrated a distinct epigenetic landscape of memory ILC2s and identified Bach2 and AP1 (JunD and Fosl2) motifs as major drivers of altered gene accessibility. scRNA-seq, gene knockout, and signaling studies suggest that repetitive allergenic stress induces a gene repression program involving Nr4a2, Zeb1, Bach2, and JunD and a preparedness program involving Fhl2, FosB, Stat6, Srebf2, and MPP7 in memory ILC2s. A mutually regulated balance between these two programs establishes and maintains memory. The preparedness program (e.g., Fhl2) can be activated with a subthreshold cognate stimulation, which down-regulates repressors and activates effector pathways to elicit the memory-driven phenotype.

MDS-associated SF3B1 mutations enhance proinflammatory gene expression in patient blast cells

Two factors known to contribute to the development of myelodysplastic syndrome (MDS) and other blood cancers are (i) somatically acquired mutations in components of the spliceosome and (ii) increased inflammation. Spliceosome genes, including SF3B1, are mutated at high frequency in MDS and other blood cancers; these mutations are thought to be neomorphic or gain-of-function mutations that drive disease pathogenesis. Likewise, increased inflammation is thought to contribute to MDS pathogenesis; inflammatory cytokines are strongly elevated in these patients, with higher levels correlating with worsened patient outcome. In the current study, we used RNAseq to analyze pre-mRNA splicing and gene expression changes present in blast cells isolated from MDS patients with or without SF3B1 mutations. We determined that SF3B1 mutations lead to enhanced proinflammatory gene expression in these cells. Thus, these studies suggest that SF3B1 mutations could contribute to MDS pathogenesis by enhancing the proinflammatory milieu in these patients.

Comparative Profiling of the Immune System in Sarcoidosis via CITE-Seq and Flow Cytometry

CITE-Seq enables simultaneous single cell transcriptome and proteome analysis via combining single cell RNA-seq with oligo-labeled antibodies. Conventional techniques such as flow or mass cytometry have caveats including the number of epitopes accurately detected or an inability to recover samples for transcriptome analysis. These limitations are prohibitive for multivariate analysis of limited clinical samples. We developed a CITE-seq assay that enables comprehensive immune cell profiling of Sarcoidosis. Sarcoidosis is a granulomatous lung disease characterized by abnormal CD4+ T cell Th1 activity. However, the disease etiology and course are variable and the underlying molecular drivers remain unknown. The long-term goal of this study is to utilize CITE-seq to identify immune molecular pathways of Sarcoidosis pathogenesis. In our initial studies, we analyzed PBMC’s by CITE-seq vs. flow cytometry and observed similar cell profiles. However, the synergy of protein detection coupled with transcriptome analysis via CITE-seq enhanced cell subset identification vs. flow or scRNA-seq alone. We utilized CITE-seq in an ongoing longitudinal study of Sarcoidosis subjects to enhance resolution of the immune components contributing to disease. We compared CITE-seq to a flow cytometry panel analyzing the differential contributions of various CD4+ T cell lineages. The enhanced granularity provided by CITE-seq elucidated molecular pathways associated with disease pathogenesis. Thus, moving forward CITE-seq can provide the resolution and multivariate data collection required to identify the inflammatory drivers of Sarcoidosis.

Linking environmental exposures to molecular regulation of inflammation via epigenetic histone signatures in an exacerbation prone pediatric asthma cohort

Environmental exposures, such as air pollution, are correlated with asthma susceptibility and airway inflammation. Epigenetic mechanisms can translate these exposures to regulation of molecular pathways that drive asthma pathogenesis. Indeed, specific epigenetic modifications have been linked to regulation of asthma-associated inflammation. Yet, there have been no studies linking environmental exposures to direct regulation of molecular mechanisms driving dysfunction of inflammation in pediatric asthma. Here we examined a cohort of exacerbation prone pediatric asthmatics tracking exposure through multiple air monitoring methods, including personalized vest monitors, stationary monitors, and Colorado DPHE monitors. We performed ChIP-seq examining histone modifications in PBMCs and integrated the epigenetic data with the environmental exposure data from the air pollution monitors. Our results statistically linked specific histone modifications in PBMCs to specific types of environmental exposures within the pediatric asthmatics. Annotation of these histone modifications to proximal genes identified a potential immune program regulating asthma inflammation. Concomitant examination of the PBMC transcriptome enabled functional analysis of epigenetic regulation of these immune genes. The resultant molecular profiles can be used to identify biomarkers for patient stratification and disease course prediction. Moreover, these studies identify a potential link between the molecular programming associated with environmental exposures and regulation of key biological pathways, which alter immune cell activity that ultimately can increase asthma exacerbation in children.

CHD4 is essential for transcriptional repression and lineage progression in B lymphopoiesis

Cell lineage specification is a tightly regulated process that is dependent on appropriate expression of lineage and developmental stage-specific transcriptional programs. Here, we show that Chromodomain Helicase DNA-binding protein 4 (CHD4), a major ATPase/helicase subunit of Nucleosome Remodeling and Deacetylase Complexes (NuRD) in lymphocytes, is essential for specification of the early B cell lineage transcriptional program. In the absence of CHD4 in B cell progenitors in vivo, development of these cells is arrested at an early pro-B-like stage that is unresponsive to IL-7 receptor signaling and unable to efficiently complete V(D)J rearrangements at Igh loci. Our studies confirm that chromatin accessibility and transcription of thousands of gene loci are controlled dynamically by CHD4 during early B cell development. Strikingly, CHD4-deficient pro-B cells express transcripts of many non-B cell lineage genes, including genes that are characteristic of other hematopoietic lineages, neuronal cells, and the CNS, lung, pancreas, and other cell types. We conclude that CHD4 inhibits inappropriate transcription in pro-B cells. Together, our data demonstrate the importance of CHD4 in establishing and maintaining an appropriate transcriptome in early B lymphopoiesis via chromatin accessibility.

Mifepristone increases mRNA translation rate, triggers the unfolded protein response, increases autophagic flux, and kills ovarian cancer cells in combination with proteasome or lysosome inhibitors

The synthetic steroid mifepristone blocks the growth of ovarian cancer cells, yet the mechanism driving such effect is not entirely understood. Unbiased genomic and proteomic screenings using ovarian cancer cell lines of different genetic backgrounds and sensitivities to platinum led to the identification of two key genes upregulated by mifepristone and involved in the unfolded protein response (UPR): the master chaperone of the endoplasmic reticulum (ER), glucose regulated protein (GRP) of 78 kDa, and the CCAAT/enhancer binding protein homologous transcription factor (CHOP). GRP78 and CHOP were upregulated by mifepristone in ovarian cancer cells regardless of p53 status and platinum sensitivity. Further studies revealed that the three UPR-associated pathways, PERK, IRE1α, and ATF6, were activated by mifepristone. Also, the synthetic steroid acutely increased mRNA translation rate, which, if prevented, abrogated the splicing of XBP1 mRNA, a non-translatable readout of IRE1α activation. Moreover, mifepristone increased LC3-II levels due to increased autophagic flux. When the autophagic-lysosomal pathway was inhibited with chloroquine, mifepristone was lethal to the cells. Lastly, doses of proteasome inhibitors that are inadequate to block the activity of the proteasomes, caused cell death when combined with mifepristone; this phenotype was accompanied by accumulation of poly-ubiquitinated proteins denoting proteasome inhibition. The stimulation by mifepristone of ER stress and autophagic flux offers a therapeutic opportunity for utilizing this compound to sensitize ovarian cancer cells to proteasome or lysosome inhibitors.

Expression profiling of in vivo ductal carcinoma in situ progression models identified B cell lymphoma-9 as a molecular driver of breast cancer invasion

Introduction

There are an estimated 60,000 new cases of ductal carcinoma in situ (DCIS) each year. A lack of understanding in DCIS pathobiology has led to overtreatment of more than half of patients. We profiled the temporal molecular changes during DCIS transition to invasive ductal carcinoma (IDC) using in vivo DCIS progression models. These studies identified B cell lymphoma-9 (BCL9) as a potential molecular driver of early invasion. BCL9 is a newly found co-activator of Wnt-stimulated β-catenin-mediated transcription. BCL9 has been shown to promote progression of multiple myeloma and colon carcinoma. However BCL9 role in breast cancer had not been previously recognized.

Methods

Microarray and RNA sequencing were utilized to characterize the sequential changes in mRNA expression during DCIS invasive transition. BCL9-shRNA knockdown was performed to assess the role of BCL9 in in vivo invasion, epithelial-mesenchymal transition (EMT) and canonical Wnt-signaling. Immunofluorescence of 28 patient samples was used to assess a correlation between the expression of BCL9 and biomarkers of high risk DCIS. The cancer genome atlas data were analyzed to assess the status of BCL9 gene alterations in breast cancers.

Results

Analysis of BCL9, by RNA and protein showed BCL9 up-regulation to be associated with DCIS transition to IDC. Analysis of patient DCIS revealed a significant correlation between high nuclear BCL9 and pathologic characteristics associated with DCIS recurrence: Estrogen receptor (ER) and progesterone receptor (PR) negative, high nuclear grade, and high human epidermal growth factor receptor2 (HER2). In vivo silencing of BCL9 resulted in the inhibition of DCIS invasion and reversal of EMT. Analysis of the TCGA data showed BCL9 to be altered in 26 % of breast cancers. This is a significant alteration when compared to HER2 (ERBB2) gene (19 %) and estrogen receptor (ESR1) gene (8 %). A significantly higher proportion of basal like invasive breast cancers compared to luminal breast cancers showed BCL9 amplification.

Conclusion

BCL9 is a molecular driver of DCIS invasive progression and may predispose to the development of basal like invasive breast cancers. As such, BCL9 has the potential to serve as a biomarker of high risk DCIS and as a therapeutic target for prevention of IDC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0630-z) contains supplementary material, which is available to authorized users.

Invited review: Enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions

Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1 kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2 e/kg of ECM in extensive systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding, and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%, whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and management approaches, including improvements in heat abatement, disease and fertility management, performance-enhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.

Effects of wortmannin, sodium nitroprusside, insulin, genistein, and guanosine triphosphate on chemotaxis and cell growth of Entodinium caudatum, Epidinium caudatum, and mixed ruminal protozoa

The mechanisms by which ruminal protozoa sense and migrate toward nutrients are not fully understood. Chemotaxis by many diverse eukaryotic cells is mediated by phosphatidylinositol-3-kinase, which is highly conserved in receptor tyrosine kinase (RTK) signaling pathways and consistently inhibited by wortmannin. In experiment 1a, increasing the concentration of wortmannin inhibited cell growth nonlinearly at 24h of a culture of the rumen protozoan Entodinium caudatum, but high variability prevented growth inhibition of Epidinium caudatum from reaching significance. In experiment 1b, increasing the insulin concentration recovered 24-h cell counts for both cultures, depending on wortmannin concentration. In experiment 2, addition of sodium nitroprusside (Snp; activator of protein kinase G for cilial beat reversal in nonrumen ciliate models) at 500µM or wortmannin at 200µM in beakers containing rumen fluid decreased random swimming by mixed entodiniomorphids into capillary tubes (inserted into beakers) containing saline. Both Snp and wortmannin increased chemotaxis into tubes containing glucose compared with the beaker control. For isotrichids, beaker treatments had no response. Glucose increased chemotaxis, but peptides decreased chemotaxis even when combined with glucose. In experiment 3, we assessed preincubation of genistein (a purported RTK blocker in nonrumen ciliate models) at 40 or 400µM in beakers and guanosine triphosphate (GTP; a universal chemorepellent in nonrumen ciliate models, perhaps mediated through an RTK) at 10 or 100µM combined with glucose in capillary tubes. Neither genistein nor GTP affected chemotaxis toward glucose for entodiniomorphids. However, GTP at 100µM reduced chemotaxis toward glucose for isotrichids. After the animal is fed, isotrichids that are depleted in glycogen migrate to the dorsal area of the rumen, and the rapid uptake of sugars is enhanced through strong chemotaxis but can be reversed by peptides or GTP. In contrast, entodiniomorphids are less intensely chemoattracted to glucose than isotrichids but are chemoattracted to peptides. Entodiniomorphids' chemoattraction appears to be integrated with slower but prolonged availability of energy from digesting starch and fiber.

Actual and perceived intrafamilial attitudes of late adolescents and their parents

The present study assessed the comparability of adolescents' (N=184), their mothers' (N=184), and their fathers' (N=184) attitudes toward contemporary societal issues, as well as each familial group's perceptions of the other two groups' attitudes. Results of multivariated analyses of variance indicated that while there were significant overall differences between adolescents' and either parent's self-ratings for the 36 questionnaire items (dealing with such topics as drug use, sexuality, and dress codes), major (i.e., 2-scale-point) differences between generational groups existed on only about 20% of the items. However, as predicted, both adolescents and parents misperceived the extensiveness of the divisions between them. Adolescents significantly overestimated the number of major differences between themselves and their mothers and fathers, while these two parental groups significantly underestimated such divisions. These distortions in perceived attitudes were also reflected in the results of correlational analyses assessing intrafamilial attitude consistencies and inconsistencies across the 36 items. Self-alternative-family-members' perceived attitudes correlations showed greater consistency than existed in the self-alternative-family-members' actual attitudes correlations. Moreover, both analyses of variance and correlational analyses indicated that there was greater similarity between the actual attitudes of the mothers and fathers than between either parental group and their children. These results are discussed in terms of the cognitive and emotional significance of the intrafamilial attitudes of adolescents and parents.

Effects of jugular-infused lysine, methionine, and branched-chain amino acids on milk protein synthesis in high-producing dairy cows

In addition to lysine and methionine, current ration-balancing programs suggest that branched-chain amino acid (BCAA) supply may also be limiting in dairy cows. The objective of this study was to investigate whether BCAA, leucine, isoleucine, and valine become limiting for milk protein synthesis when methionine and lysine supply were not limiting. Nine multiparous Holstein cows with an average milk production of 53.5±7.1 kg/d were randomly assigned to 7-d continuous jugular infusions of saline (CTL), methionine and lysine (ML; 12 g and 21 g/d, respectively), or ML plus leucine, isoleucine, and valine (ML+BCAA; 35 g, 15 g, and 15 g/d, respectively) in a 3×3 Latin square design with 3 infusion periods separated by 7-d noninfusion periods. The basal diet consisted of 40% corn silage, 14% alfalfa hay, and a concentrate mix, and respectively supplied lysine, methionine, isoleucine, leucine, and valine as 6.1, 1.8, 4.7, 8.9, and 5.3% of metabolizable protein. Dry matter intake (23.9 kg/d), milk yield (52.8 kg/d), fat content (2.55%), fat yield (1.33 kg/d), lactose content (4.77%), lactose yield (2.51 kg/d), and milk protein efficiency (0.38) were similar across treatments. Protein yield and protein content were not significantly different between ML (1.52 kg/d and 2.88%, respectively) and ML+BCAA (1.51 kg/d and 2.83%, respectively), but they were significantly greater than that of CTL (1.39 kg/d and 2.71%). Cows that received ML+BCAA had less milk urea nitrogen content (10.9 mg/dL) compared with milk of CTL cows (12.4 mg/dL) and ML cows (11.8 mg/dL). Whereas high-producing cows responded positively to methionine and lysine supplementation, no apparent benefits of BCAA supplementation in milk protein synthesis were found. Infusion of BCAA may have stimulated synthesis of other body proteins, probably muscle proteins, as evidenced by decreased milk urea nitrogen.

Target gene selectivity of the myogenic basic helix–loop–helix transcription factor myogenin in embryonic muscle

The myogenic regulatory factors MyoD and myogenin are crucial for skeletal muscle development. Despite their importance, the mechanisms by which these factors selectively regulate different target genes are unclear. The purpose of the present investigation was to compare embryonic skeletal muscle from myogenin(+/+) and myogenin(-/-) mice to identify genes whose expression was dependent on the presence of myogenin but not MyoD and to determine whether myogenin-binding sites could be found within regulatory regions of myogenin-dependent genes independent of MyoD. We identified a set of 140 muscle-expressed genes whose expression in embryonic tongue muscle of myogenin(-/-) mice was downregulated in the absence of myogenin, but in the presence of MyoD. Myogenin bound within conserved regulatory regions of several of the downregulated genes, but MyoD bound only to a subset of these same regions, suggesting that many downregulated genes were selective targets of myogenin. The regulatory regions activated gene expression in cultured myoblasts and fibroblasts overexpressing myogenin or MyoD, indicating that expression from exogenously introduced DNA could not recapitulate the selectivity for myogenin observed in vivo. The results identify new target genes for myogenin and show that myogenin's target gene selectivity is not based solely on binding site sequences.

Hsp90 and Developmental Networks

The most abundant cytoplasmic chaperone of eukaryotic cells, Hsp90 is a hub in developmental regulatory networks and the first example described of the phenomenon of molecular buffering. As a chaperone for many different signaling proteins, Hsp90 maintains the clarity and strength of communication within and between cells, concealing developmental and stochastic variations that otherwise cause abrupt morphological changes in a large variety of organisms, including Drosophila and Arabidopsis. The chapter provides a framework for understanding how Hsp90 controls the sudden appearance of novel morphologies. We start with a discussion of the longstanding problem of hidden polygenic variation and then introduce the idea of signal transduction thresholds in mediating the effect of Hsp90 on the expression of phenotypic variation. This leads to a discussion of the role of nonlinearity in creating thresholds for sudden changes in cellular responses to developmental signals. We end with speculation on the potentially pivotal role of Hsp90 in controlling the developmental networks that determine morphological stasis and change in evolution.

Loss of myogenin in postnatal life leads to normal skeletal muscle but reduced body size

Although the mechanisms regulating the formation of embryonic skeletal muscle in vertebrates are well characterized, less is known about postnatal muscle formation even though the largest increases in skeletal muscle mass occur after birth. Adult muscle stem cells (satellite cells) appear to recapitulate the events that occur in embryonic myoblasts. In particular, the myogenic basic helix-loop-helix factors, which have crucial functions in embryonic muscle development, are assumed to have similar roles in postnatal muscle formation. Here, we test this assumption by determining the role of the myogenic regulator myogenin in postnatal life. Because Myog-null mice die at birth, we generated mice with floxed alleles of Myog and mated them to transgenic mice expressing Cre recombinase to delete Myog before and after embryonic muscle development. Removing myogenin before embryonic muscle development resulted in myofiber deficiencies identical to those observed in Myog-null mice. However, mice in which Myog was deleted following embryonic muscle development had normal skeletal muscle, except for modest alterations in the levels of transcripts encoding Mrf4 (Myf6) and Myod1 (MyoD). Notably, Myog-deleted mice were 30% smaller than control mice, suggesting that the absence of myogenin disrupted general body growth. Our results suggest that postnatal skeletal muscle growth is controlled by mechanisms distinct from those occurring in embryonic muscle development and uncover an unsuspected non-cell autonomous role for myogenin in the regulation of tissue growth.

Effects of a polymer-coated urea product on nitrogen metabolism in lactating Holstein dairy cattle

The purpose of this study was to evaluate the impact of polymer-coated urea on nitrogen retention, rumen microbial growth, and milk production and composition. Coated urea (CU) that is more slowly hydrolyzed to ammonia than unprotected urea could potentially be used more efficiently by rumen microorganisms. Eight cows were offered each of three diets in a randomized crossover design. Each treatment period consisted of a 14-d adjustment period and a 5-d collection period. Diets were formulated to maintain milk production while reducing plasma urea nitrogen concentrations and urinary nitrogen excretion. Diets consisted of corn silage, mixed grass/legume haylage, chopped alfalfa hay, corn meal, protein, vitamin and mineral supplements, in a total mixed ration and fed ad libitum. The diets contained 17.9%, 18.1%, and 16.4% CP and 0, 0.77%, and 0.77% CU (dry matter basis) and are denoted as CP18-CU, CP18+CU, and CP16+CU, respectively. Individual feed intakes were measured, and total fecal, and urine collections were conducted. Cows were milked twice daily at 0500 and 1700 h, and the milk sampled for composition and milk urea N analysis. Dry matter intake averaged 23.5 +/- 0.2 kg/d and was not altered by diet. Also, milk fat and true protein were not altered by diet and averaged 3.72 and 3.07%, respectively. Milk yield was highest for diets CP18-CU and CP18+CU. Significant differences were observed in N intake and excretion in urine, feces, and milk between dietary treatments. Cows fed CP16+CU consumed 11% less N than in CP18-CU. Cows fed CP18+CU showed the highest excretion of N in urine, and together with CP16+CU, the lowest N excretion in feces. Nitrogen excretion in milk was lower for cows fed CP16+CU. Calculated N balance was not significantly different between diets nor was it significantly different from zero. Efficiency of N capture in milk protein as a function of N intake was higher for animals on CP16+CU. Urinary excretion of purine derivatives was not different between diets, and estimated microbial CP was also similar. Coated urea was not effective at reducing nitrogen excretion by dairy cattle.

Physical and mechanical characteristics of tibias from transgenic mice expressing mutant bovine growth hormone genes

Physical and mechanical characteristics of tibia from mice expressing either the M4, M11, or G119K mutant bovine growth hormone (bGH) gene and displaying large, near-normal, or small-size phenotypes, respectively, were compared to those of non-transgenic, control mice (NTC). Three animals of each strain were euthanized at 28, 38, 48, 58, and 68 days of age. Variables were regressed against age to establish the pattern of change throughout the experiment, and the regression results are presented. Tibias from G119K were shorter (13.1 mm) and lighter (37.3 mg) than those from other strains, and M4 tibias were heavier (87.9 mg) and longer (16.6 mm) at 70 days of age. The ratio of tibia length to body weight suggests longitudinal bone growth was not reduced as much as overall growth in G119K mice. The external and internal dimensions of the G119K tibias were smaller than the other strains whereas the M4 tibias were somewhat larger. Differences in physical dimensions between the NTC and M11 mice did not greatly affect bone mechanical characteristics. Tibias from M4 mice resisted more load at both flexure and breaking compared to the other strains. At 50 days of age, stress at flexure was greater at all ages for G119K mice (12.4 kg/mm2) and was decreased in M4 mice (8.5 kg/mm2). The bGH mutations produce different effects on bone growth and its mechanical characteristics. There also may be differential tissue responsiveness to the mutant bGH analogs, as longitudinal growth was not as affected as empty body growth in the G119K mice. These transgenic mouse strains provide valuable models to study bone growth, formation, and reformation in response to GH regulation, and more importantly, the M4 and G119K mice may serve as a model in which the priorities for GH action on bone vs muscle may be determined.

Growth hormone (GH) receptors, binding proteins and IGF-I concentrations in the serum of transgenic mice expressing bovine GH agonist or antagonist

We have examined the regulation of hepatic growth hormone receptors (GH-R) and serum GH binding proteins (GHBP) in transgenic mice expressing an antagonist of bovine growth hormone (bGH), G119K-bGH, and consequently exhibiting a growth suppressed dwarf phenotype. Specific GHBP could be measured in transgenic dwarf mouse serum only by immunological methods (RIA), because these mice have a very high concentration of mutated bGH in circulation (> 1 microgram/ml) and, therefore, almost all GHBP is bound to G119K-bGH and cannot be quantitated in binding assays. The concentrations of GHBP were 0.6 +/- 0.4 nM and 1.7 +/- 0.4 nM for normal and dwarf mice respectively. The concentrations of free GHBP in normal mice and in transgenic mice expressing wild-type GH can be calculated using chromatographic techniques as the dissociation constant (Kd) and the ratio of bound 125I-GH to free 125I-GH in the serum ([GHBP]free = B/F.Kd). In agreement with the assumption that GHBP reflects GH-R status, liver uptake of injected labeled bGH was greatly reduced in transgenic dwarfs in comparison with normal mice or with transgenic mice expressing wild-type bGH (liver/blood ratio of 0.48 +/- 0.21, 2.7 +/- 0.2, and 1.3 +/- 0.3 respectively) indicating that the high concentration of the mutated bGH (G119K-bGH) prevents labeled bGH uptake, as was expected from the dwarf phenotype. 125I-bGH taken up by the liver of transgenic dwarf mice was found in a smaller molecular species than in normal mice, compatible with the presence of 1:1 [(GH-R):GH] complexes instead of the 2:1 [(GH-R)2:GH] or 2:2 [(GHBP)2:(GH)2] complexes found in normal mice. The concentration of IGF-I, the principal mediator of GH activity, in the G119K-bGH transgenic mice was correlated with the concentration of free GHBP. This allowed us to use free GHBP concentration as a marker of the effects of the active endogenous hormone (mGH) on liver receptors in the presence of different concentrations of the antagonist of GH. The levels of GHBP in serum, as well as the concentration of GH-R in liver microsomes from mice expressing the bGH antagonist, are up-regulated by the high concentration of G119K-bGH (85%), but significantly less so than that which could be expected for the same concentration of native GH (220-275%). This up-regulation suggests that the G119K-bGH antagonist is internalized and induces synthesis of the receptor and of the binding protein.

Consequences of overexpression of growth hormone in transgenic mice on liver cytochrome P450 enzymes

The effect of growth hormone (GH) on cytochrome P450 (CYP) and P450-dependent monooxygenases was studied in 4-, 6-, 8-, and 10-month-old female bovine growth hormone (bGH) transgenic mice that overexpress GH. Nontransgenic female mice (C57/SJL) littermates were used for baseline determinations. The body weights of the bGH mice were approximately 35% greater than those of the controls. The liver weights were 2-fold higher than those of the controls, resulting in a 25-60% increase in liver/body weight ratio during the life span of the bGH mice when compared with the controls. Similar increases in heart and kidney weights were observed. Since the GH transgene was transcriptionally regulated by a metallothionein-I gene promoter, metallothionein concentrations in livers of transgenic and nontransgenic mice were measured. No significant differences were observed. In marked contrast to increases in liver weights, hepatic cytochrome P450 content, benzphetamine N-demethylase, and benzo [a] pyrene hydroxylase activities were decreased by 36, 42 and 75%, respectively. No age-related changes in the decrease of the monooxygenases were observed. Microsomal heme oxygenase (HO) in the liver was induced 44% above the control values. Immunoblot analysis also showed a marked increase in HO-1 in the bGH mice. These results indicate that GH suppresses the carcinogen-metabolizing enzyme benzo [a] pyrene hydroxylase and the drug-metabolizing enzyme benzphetamine N-demethylase. This suppression was accompanied by an induction of HO activity in bGH transgenic mice. The consequences of prolonged exposure to supraphysiological levels of this hormone cannot always be predicted from the known physiological actions of GH.

Expression of mutant bovine growth hormone genes in mice perturbs age-related nutrient utilization patterns

Three lines of transgenic mice expressing mutant bovine growth hormone (bGH) genes and displaying small (G119K), near normal (M11) or large (M4) phenotypes and nontransgenic control (NTC) mice were used to determine GH-associated, age-specific changes in empty body composition. The single amino acid substitution in G119K mice reduced the quantities (P < 0.001) and early rates (P < 0.05) of deposition for water, protein and ash but resulted in similar quantities of fat as the NTC mice. The change in relative quantities of empty body components indicated the G119K analogue altered nutrient partitioning, basal metabolism and (or) nutrient availability to effect the differential observed in body composition. The two amino acid substitutions in the bGH gene expressed by the M11 mice caused only a small change in phenotype, but age-related changes in the accretion of protein, fat and ash indicated these mice were not mature by 68 d of age. The bGH analogue produced by the M4 mice resulted in a doubling (P < 0.001) of body weight in comparison with the NTC mice, a result of the increasing (P < 0.001) rate of weight gain. Empty body component gain of the M4 mice also indicated they had not yet matured by 68 d of age. The G119K and M4 mutant forms of bGH altered rates and composition of growth, possibly through redirection of tissue nutrient utilization, modification of nutrient metabolism, and(or) nutrient availability.

Growth patterns and body composition of transgenic mice expressing mutated bovine somatotropin genes

The objectives of this study were to determine growth rates, feed intakes, feed efficiencies, and chemical composition of mice from three transgenic lines in 10-d periods from weaning to near maturity. Lines M4, M11, and G119K express bovine somatotropin (bST) mutations E117L, L121P-E126G, and G119K and display phenotypes of large, near normal, and small body size, respectively. M4 mice were 28% larger at 28 d and 84% larger at 68 d than non-transgenic control (NTC) mice. M11 mice were the same size at 28 d as NTC but were 25% larger at 68 d. G119K mice were 34% and 25% smaller than NTC at 28 and 68 d, respectively. Growth rates of G119K mice and NTC were similar, whereas growth rates of M11 and M4 mice were increased (P < .05). Feed intakes of M4 and M11 mice were greater than those of NTC mice (P < .05), whereas feed intakes of G119K mice were lower than those of NTC mice (P < .05). Feed efficiency (gain/feed) was improved in M4 and M11 mice (P < .05) and not altered in G119K mice compared to that of NTC mice (P > .05). Chemical composition was also altered by expression of bST analogs in transgenic mice. G119K and M4 mice had increased body fat percentages and decreased body protein percentages in comparison to M11 and NTC mice (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

The use of transgenic mice in nutrition research

The ability to generate transgenic mice that express exogenous genes, express genes in a tissue specific manner, or do not express an endogenous gene will dramatically impact nutritional studies. Use of transgenic animals will greatly expand the types of experiments that can be performed, for example, by permitting researchers to examine specific mechanisms underlying nutritional relationships. These studies can be viewed from two perspectives; the effect of nutrition in general or nutrients in specific on the regulation of gene expression; and conversely, the effects of gene expression upon nutrient utilization or other aspects of metabolism. In addition, transgenic animal models have been and can be established to characterize human pathologies, e.g., pituitary gigantism or atherosclerosis, and the roles and interactions of nutrition in these and other metabolic diseases may then be evaluated. The use of transgenic animals in nutrition research is new and quite fertile, and exciting results will continue to surface.

In vitro and in vivo development of bovine embryos from zygotes and 2-cell embryos microinjected with exogenous DNA

The objectives of these experiments were: 1) to determine an effective culture method for production of transferable bovine embryos following exogenous DNA microinjection; 2) to determine the effect of these methods on the ability of the injected zygotes and 2-cell embryos to develop in vivo; and, 3) to compare development of embryos microinjected as zygotes or 2-cell embryos. DNA fragments encoding bovine growth hormone (bGH), bGH-10Delta6, and a bGH antagonist, bGH-M8 (5) were used. A total of 639 zygotes and 153 2-cell embryos were injected. Zygotes and 2-cell embryos microinjected with bGH-M8 were incubated for 6 days in oviducts of intermediate recipients (rabbits or sheep) or co-cultured in vitro with bovine oviduct epithelial cells. Zygotes and 2-cell embryos microinjected with bGH-10Delta6 were co-cultured in vitro only. The most effective method for the production of transferable bovine embryos following exogenous DNA microinjection was via in vitro co-culturing with bovine epithelial cells. For example, 32.3% of the bGH-M8 and 33.5% of the bGH-10Delta6 microinjected zygotes reached the morula/blastocyst stage while 48.4% and 63.0% of the 2-cell embryos injected with bGH-M8 and bGH-10Delta6, respectively, developed to the morula/blastocyst stage. The percentage of blastocysts obtained for control, non-injected zygotes and 2-cell embryos was 34.5% and 69.6%, respectively. The developmental rate to the morula/blastocyst stage was approximately 20% greater for embryos obtained from microinjected 2-cell embryos relative to microinjected zygotes. However, there was no significant difference in pregnancy rates following transfer of these blastocysts to cow uteri.

Recombinant bovine somatotropin's effects on patterns of nutrient utilization in lactating dairy cows

The discussion of effects of recombinant bovine somatotropin (rbST) administration on the metabolism of lactating dairy cows presented is divided into two parts: short term and long term. Short-term effects are evident during the initial period of treatment when milk production is increased but feed intake has not yet increased. During this period body reserves are mobilized to support the higher rates of milk production. This phase is very similar to the early lactation condition, when energy requirements for milk production also exceed energy intake. Two notable exceptions to this analogy are that glucose and beta-hydroxybutyrate concentrations are not altered during rbST treatment but are influenced by stage of lactation. After the initial phase of rbST treatment, feed intake increases to compensate for the increase in milk production. During this phase the metabolism of cows treated with rbST essentially mirrors the metabolism of untreated cows producing comparable amounts of milk.

Effects of somatotropin and substrates on patterns of liver metabolism in lactating dairy cattle

Objectives of this study were to quantitate metabolite fluxes in ruminant liver and to delineate effects of recombinant bST on patterns of nutrient metabolism by liver. Nineteen multiparous cows ranging in previous lactational performance from 6400 to 13,500 kg per 305-d lactation were treated with either placebo or bST (40 mg/d) from wk 11 to 18 of lactation. Liver tissue was collected at slaughter. Tissue slices were incubated with various 14C-labeled substrates, and rates of conversion of label to CO2 and metabolites were measured. In vivo recombinant bST treatment increased in vitro conversion of [1-14C]propionate and [2-14C]acetate to glucose more than twofold. At 2.5 mM propionate, bST-treated cows converted propionate to glucose at 90% efficiency. Recombinant bST increased [14C]bicarbonate incorporation into glucose five-fold. Overall, bST treatment resulted in greater C flow from propionate and acetate through the TCA cycle. Acetate had only small effects on propionate metabolism and no effects on lactate plus pyruvate metabolism. Unexpectedly, propionate decreased acetate conversion to ketone bodies. Suggested mechanisms for this observation include depletion of coenzyme A and allosteric regulation of carnitine palmitoyltransferase I by methylmalonyl-coenzyme A formed from propionate. In summary, bST treatment resulted in increased rates of gluconeogenesis and oxidation in liver in support of lactation.

Structure of body-build stereotypes: a methodological analysis

College students ( N = 182) were Ss in a study assessing the comparability of body build stereotypes as depicted through the use of various response formats. Stereotypes toward Endomorph and Mesomorph body types, respectively, were derived through responses to: (1) a traditional, forced-choice format; (2) a dimensionalized, bipolar item format requiring placement of 10 Endomorphs and 10 Mesomorphs, respectively, along each of 10 nine-point dimensions; (3) a format identical to Number 2 except in the requirement of only one Endomorph or Mesomorph attribution per dimension; and (4) a format requiring the estimation of the percentage of time an Endomorph and a Mesomorph, respectively, manifested the item-characteristic. Results indicated that although mean responses derived from the latter three methods were consistent in direction with corresponding forced-choice, frequency data, the intradimensional separation of most of these means was not markedly disparate; moreover, correlations between forced-choice responses and any and all of the latter methods were markedly low, although correlations among these latter methods were moderate. It was concluded that inferences drawn about the structure of body build stereotypes, based on data derived from forced-choice formats, were not supported by the data provided with the latter three formats. Implications for other stereotype research were discussed.