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Somatic mutations of the estrogen receptor 1 gene (ESR1) is an emerging mechanism of acquired resistance to endocrine therapy in hormonal breast cancers. Hotspot point mutations in the ligand- binding domain of estrogen receptor α (ER) and genomic rearrangements producing ESR1 fusion genes are the two major types of mutations that are associated with endocrine resistance. The crosstalk between X-box binding protein 1 (XBP1), a key transcription factor of the unfolded protein response (UPR) and ER signalling creates a positive feedback loop that results in increased expression of XBP1 in ER-positive breast cancer. Here we report that XBP1 co-operated with point mutants (Y537S, D538G) and fusion mutants (ESR1-YAP1, ESR1-DAB2) of ESR1 to increase their transcriptional activity. XBP1 was required for optimal expression of estrogen-regulated genes, and up to 40% of XBP1-dependent genes were estrogen-responsive genes. Knockdown of XBP1 in genome-edited MCF7 cells expressing Y537S mutant reduced their growth, re-sensitized them to anti-estrogens and attenuated the constitutive and estrogen-stimulated expression of estrogen-regulated genes. Our study provides a rationale for overcoming endocrine resistance in breast cancers expressing ESR1 mutation by combining the XBP1 targeting agents with anti-estrogen agents., Cell biology; Transcriptomics; Biochemistry; Molecular biology; Cancer research; ESR1 mutations, Endocrine resistance, XBP1, ER-Positive breast cancer

Recent evidence has shown that the miR-17-92 cluster can function either as oncogene or tumor suppressor in human cancers. The function of miR-17-92 in subtypes of breast cancer remains largely unknown. The expression of miR-17-92 is elevated in triple negative breast cancer (TNBC) but reduced in estrogen receptor (ER)-positive breast cancer (ERPBC). We show that increased expression of miRNAs belonging to the miR-17-92 cluster is associated with poor outcome in TNBC, whereas the expression of miR-17-92 miRNAs is with good outcome in ERPBC. We show that ectopic expression of miR-17-92 inhibited cell growth and invasion of ER-positive and HER2-enriched cells. On the contrary, miR-17-92 expression enhanced cell growth and invasion of TNBC cells. Further, we found that miR-17-92 expression sensitized MCF7 cells to chemotherapeutic compounds, whereas it rendered SKBR3 cells resistant to them. We found that expression of ADORA1 was reduced by miR-17-92-expressing breast cancer cells, specifically in ERPBC. We observed an inverse correlation between the expression of ADORA1 and miR-17-92 in human breast cancer. Treatment with DPCPX, a selective ADORA1 antagonist, abolished the difference in the growth of control and miR-17-92 overexpressing MCF7 cells and identified ADORA1 as a key functional target of miR-17-92 in ERPBC. Furthermore, increased expression of ADORA1 in ERPBC is associated with a poor outcome. Our observations underscore the context-dependent role of miR-17-92 in breast cancer subtypes and suggest that miR-17-92 could serve as novel prognostic markers in breast cancer.

Anemia is a condition that affects over 1.6 billion people worldwide untreated, the disease could lead to increased morbidity and mortality during pregnancy, affecting both the mother and the unborn child. This paper presents the measured dielectric properties of whole blood samples from 176 patients obtained from a hematology clinic; with 80 samples from male patients and 96 samples from female patients. Measurements were performed using a Keysight slim form probe and Keysight network analyzer to obtain the dielectric properties over a wide frequency range (500 MHz-8.5 GHz). A multiple linear regression analysis is performed to identify which components of the blood show the highest correlation with changes in the dielectric properties. Hemoglobin (Hgb) is shown to be the biggest predictor of changes in complex permittivity, demonstrating that permittivity measurements at a single frequency can potentially be used to detect anemia. A support vector machines algorithm is trained and tested to classify between blood samples from healthy patients and blood samples from patients with anemia. The classifier is optimized using a Bayesian-optimization approach during 10-fold cross-validation and then the average performance of the final trained classifier is evaluated through 10-fold testing on unseen data sets. Using a clinical definition of anemia defined as patients having a concentration of Hgb

Background: The miR-17-92 is an oncogenic miRNA cluster that generate six mature miRNAs: miR-17, miR-18a, miR-19a, miR-20a, miR-19b-1, and miR-92-1. Accumulating evidences indicate the oncogenic role of the miR-17-92 cluster in human cancers. Amplification of 13q31-q32, which is the locus of the miR-17-92 cluster, have been reported in haematopoietic malignancies, such as B cell lymphoma. In contrast, MIR17HG was deleted in 21.9% of breast cancers and loss of heterozygosity at 13q12-q13 was associated with poor prognosis in breast cancer. This oncogenic miRNA cluster is deferentially expressed in various cancer. Since, miR-17-92 cluster shows differential expression among the cancers types, it is hypothesized that biological function may also vary depending on the context. Indeed, this cluster has been shown to act a tumour suppressor in some cancers. However, the functional role of this cluster in the subtypes of breast cancer remains largely unknown. Methods: The oncomine datasets were analysed for expression of MIR17HG in breast cancer at parameters p-value threshold of 0.01 with minimum 2-fold change. We generated stable sub-clones of MCF7, T47D, SKBR3 and MDA-MB231 cells overexpressing miR-17-92 cluster by transducing with lentivirus expressing miR-17-92. Proliferation was assessed by MTS assay and colony forming assay. Cell migration was tested using scratch method. Invasion potentiality was monitored by using matrigel Boyden chamber invasion assay. For drug response analysis, control and microRNA overexpressing sub-clones were exposed to different chemotherapeutic agents at different concentrations followed by MTS assay at different time intervals. Association of miRNAs belonging to miR-17-92 with outcome in breast cancer was determined by Kaplan-Meier analysis on METABRIC dataset. Results: We observed that expression of MIR17HG was increased in tissues and cell lines from triple negative breast cancer (TNBC) but decreased in the tissues and cell lines from the estrogen receptor (ER)-positive breast cancer. Our results showed that ectopic expression of miR-17-92 cluster significantly suppressed cell proliferation, colony formation, migration and invasion of ER-positive (MCF7, T47D) and HER2-enriched (SKBR3) cells whereas it enhanced cell proliferation, colony formation, migration and invasion in (TNBC) MDA-MB 231 cells. Further, we found that expression of miR-17-92 cluster sensitized MCF7 cells whereas it rendered SKBR3 cells resistant to chemotherapeutic compounds. Higher expression of five miRNAs of this cluster was associated with better relapse free survival (RFS) in (miR-17, miR-19a, miR-20a, miR-19b and miR-92) Luminal A subtype whereas three miRNAs of this cluster were associated with poor RFS in (miR-17, miR-18a and miR-92) HER2-enriched and (miR-17, miR-19b and miR-92) TNBC subtypes. Conclusions: Taken together our results suggest that miR-17-92 cluster acts as a tumour suppressor in ER-positive and HER2-enriched breast cancer cells but shows oncogenic role in TNBC. Our observations underscore the functional complexity of miR-17-92 in a context-dependent and cell type-dependent manner, and more investigations are warranted to fully explore the functional complexity of miR-17-92 in subtypes of breast cancer. Citation Format: Hossain MM, Arabkari V, Barua D, Gupta A, Islam MN, Gupta S. miR-17-92 cluster, an oncogenic microRNA cluster acts as a context dependent tumour suppressor in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-07-14.

The lungs are the most vulnerable site for air-borne infections. Immunologic compartmentalization of the lungs into airway lumen and interstitium has paved the way to determine the immune status of the site of pathogen entry, which is crucial for the outcome of any air-borne infections. Vaccination via the nasal route with Mycobacterium indicus pranii (MIP), a prospective candidate vaccine against tuberculosis (TB), has been reported to confer superior protection as compared to the subcutaneous (s.c.) route in small-animal models of TB. However, the immune mechanism remains only partly understood. Here, we showed that intranasal (i.n.) immunization of mice with MIP resulted in a significant recruitment of CD4+ and CD8+ T-cells expressing activation markers in the lung airway lumen. A strong memory T-cell response was observed in the lung airway lumen after i.n. MIP vaccination, compared with s.c. vaccination. The recruitment of these T-cells was regulated primarily by CXCR3–CXCL11 axis in “MIP i.n.” group. MIP-primed T-cells in the lung airway lumen effectively transferred protective immunity into naïve mice against Mycobacterium tuberculosis (M.tb) infection and helped reducing the pulmonary bacterial burden. These signatures of protective immune response were virtually absent or very low in unimmunized and subcutaneously immunized mice, respectively, before and after M.tb challenge. Our study provides mechanistic insights for MIP-elicited protective response against M.tb infection.

Current methods for building tissues usually start with a non-biological blueprint, or rely on self-organization, which does not extend to organ-scales. This has limited the construction of large tissues that simultaneously encode fine-scale cell organization. Here we bridge scales by mimicking developmental dynamics using “kinomorphs”, tissue scaffolds that undergo globally programmed shape and density changes to trigger local self-organization of cells in many locations at once. In this first report, we focus on mimicking the extracellular matrix (ECM) compaction and division into leaflets that occurs in kidney collecting duct development. We start by creating single-cell resolution cell patterns in ECM-mimetic hydrogels that are >10x larger than previously described, by leveraging photo-lithographic technology. These patterns are designed to mimic the branch geometry of the embryonic kidney collecting duct tree. We then predict the shape dynamics of kinomorphs driven by cell contractility-based compaction of the ECM using kinematic origami simulations. We show that these dynamics spur centimeter-scale assembly of structurally mature ~50 μm-diameter epithelial tubules that are locally self-organized, but globally programmed. Our approach prescribes tubule network geometry at ~5x smaller length-scales than currently possible using 3D printing, and at local cell densities comparable to in vivo tissues. Kinomorphs could be used to scaffold and “plumb” arrays of organoids in the future, by guiding the morphogenesis of epithelial networks. Such hybrid globally programmed/locally self-organized tissues address a major gap in our ability to recapitulate organ-scale tissue structure.Significance StatementEngineers are attempting to build tissues that mimic human diseases outside of the body. Although stem cells can be coaxed to form small organoids with a diversity of cell types, they do not properly organize over large distances by themselves. We report a strategy to mimic developmental processes using dynamic materials that attempt to guide a cellular “blueprint” towards a more complex tissue endpoint. We call these materials kinomorphs, combining the Greek kinó (propel, drive) and morfí (form, shape), since they seek to shepherd both the shape and developmental trajectory of cell collectives within them. Kinomorphs could pave the way towards organ-scale synthetic tissues built through a hybrid of engineering and self-organization strategies.

Accurate road maps are important for timely disaster relief efforts and risk management. Current disaster mapping is done manually by volunteers following a disaster and the process is slow and error prone. We propose a framework for identifying accessible roads in post-disaster satellite imagery by detecting changes from pre-disaster imagery, in conjunction with OpenStreetMap data. We validate our results with data from Indonesia 2018 tsunami, obtained from DigitalGlobe.

Timely disaster risk management requires accurate road maps and prompt damage assessment. Currently, this is done by volunteers manually marking satellite imagery of affected areas but this process is slow and often error-prone. Segmentation algorithms can be applied to satellite images to detect road networks. However, existing methods are unsuitable for disaster-struck areas as they make assumptions about the road network topology which may no longer be valid in these scenarios. Herein, we propose a CNN-based framework for identifying accessible roads in post-disaster imagery by detecting changes from pre-disaster imagery. Graph theory is combined with the CNN output for detecting semantic changes in road networks with OpenStreetMap data. Our results are validated with data of a tsunami-affected region in Palu, Indonesia acquired from DigitalGlobe.

Summary Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) latently infects approximately one-fourth of the world’s population. The immune mechanisms that govern progression from latent (LTBI) to active pulmonary TB (PTB) remain poorly defined. Experimentally Mtb-infected non-human primates (NHP) mirror the disease observed in humans and recapitulate both PTB and LTBI. We characterized the lung immune landscape in NHPs with LTBI and PTB using high-throughput technologies. Three defining features of PTB in macaque lungs include the influx of plasmacytoid dendritic cells (pDCs), an Interferon (IFN)-responsive macrophage population, and activated T cell responses. In contrast, a CD27+ Natural killer (NK) cell subset accumulated in the lungs of LTBI macaques. This NK cell population was also detected in the circulation of LTBI individuals. This comprehensive analysis of the lung immune landscape will improve the understanding of TB immunopathogenesis, providing potential targets for therapies and vaccines for TB control.

BCG, the only approved vaccine protects against severe form of childhood tuberculosis but its protective efficacy wanes in adolescence. BCG has reduced the incidence of infant TB considerably in endemic areas; therefore prime-boost strategy is the most realistic measure for control of tuberculosis in near future. Mycobacterium indicus pranii (MIP) shares significant antigenic repertoire with Mtb and BCG and has been shown to impart significant protection in animal models of tuberculosis. In this study, MIP was given as a booster to BCG vaccine which enhanced the BCG mediated immune response, resulting in higher protection. MIP booster via aerosol route was found to be more effective in protection than subcutaneous route of booster immunization. Pro-inflammatory cytokines like IFN-γ, IL-12 and IL-17 were induced at higher level in infected lungs of 'BCG-MIP' group both at mRNA expression level and in secretory form when compared with 'only BCG' group. BCG-MIP groups had increased frequency of multifunctional T cells with high MFI for IFN-γ and TNF-α in Mtb infected mice. Our data demonstrate for the first time, potential application of MIP as a booster to BCG vaccine for efficient protection against tuberculosis. This could be very cost effective strategy for efficient control of tuberculosis.

XBP1 is a multitasking transcription factor and a key component of the unfolded protein response (UPR). Despite the wealth of knowledge about the role of XBP1 in luminal/ER-positive breast cancer, not much is known about the effectors of XBP1 in this context. Here we show that NCOA3 is a transcriptional target of XBP1. We observed increased expression of NCOA3 during conditions of UPR and oestrogen (E2) stimulation. Further investigations revealed a role for the IRE1-XBP1 axis in the induction of NCOA3 during UPR and oestrogen signalling. We identify a novel role for NCOA3 in activation of PERK-ATF4 axis during UPR where knockdown of NCOA3 compromised the optimal activation of the PERK-ATF4 pathway. We found that NCOA3 is required for induction of XBP1 during E2 stimulation and uncover a positive feedback regulatory loop that maintains high levels of NCOA3 and XBP1 in breast cancer. Furthermore, upregulated NCOA3 was required for XBP1-mediated resistance to antihormonal agents. Increased expression of NCOA3 was associated with poor prognosis and higher levels of XBP1-S in breast cancer tissues. Our results uncover a novel steroid hormone-independent role for NCOA3 in UPR signalling. Further we identify a positive feedback regulatory loop consisting of XBP1 and NCOA3 that maintains high levels of NCOA3 and XBP1 expression in breast cancer tissues. Taken together our data identify XBP1-NCOA3 axis that regulates cell fate decisions in ER-positive breast cancer cells.

BCG (Bacillus Calmette-Guérin) is the only available vaccine against TB and is also used for the treatment of superficial bladder cancer. BCG-mediated protection against TB and bladder cancer has been shown to rely on its ability to induce superior CD4+ and CD8+ T cell responses. As the magnitude of T cell responses is defined by dendritic cell (DC) lifespan, we examined the effect of BCG on DC survival and its underlying mechanisms. It was observed that BCG stimulation enhanced DC survival and prolonged DC lifespan in a dose-dependent manner. Live BCG led to a higher DC survival compared with heat-killed BCG. FITC-Annexin V staining showed that BCG promoted DC survival by inhibiting apoptosis. Consistently, higher expressions of anti-apoptotic proteins Bcl-2 and Bcl-xL were observed in BCG-stimulated DCs. Pharmacological inhibition of Bcl-2 and Bcl-xL drastically reduced the DC survival efficacy of BCG. Comparable survival of BCG-stimulated wild-type and MyD88−/− DCs suggested that MyD88 signaling is dispensable for BCG-induced DC survival. NF-κB is one of the key regulators of innate immune responses. We observed that pharmacological inhibition of NF-κB abrogated BCG-mediated increase in DC survival and expression of anti-apoptotic proteins. These findings provide a novel insight into the effect of BCG on DC physiology., Summary: BCG enhanced the survival of dendritic cells (DCs) and prolonged their lifespan. BCG promoted DC survival by up-regulating Bcl-2 and Bcl-xL. Increased survival of BCG-stimulated DCs was dependent on NF-κB, but was independent of MyD88 signaling.

// Muhammad Mosaraf Hossain 1 , David Barua 1 , Vahid Arabkari 1 , Nahidul Islam 2 , Ananya Gupta 3 and Sanjeev Gupta 1 1 Discipline of Pathology, School of Medicine, Lambe Institute for Translational Research, National University of Ireland Galway, Galway, Ireland 2 Regenerative Medicine Institute (REMEDI) at CURAM Centre for Research in Medical Devices, School of Medicine, College of Medicine, Nursing and Health Sciences, National University of Ireland Galway, Galway, Ireland 3 Discipline of Physiology, School of Medicine, National University of Ireland Galway, Galway, Ireland Correspondence to: Sanjeev Gupta, email: sanjeev.gupta@nuigalway.ie Keywords: steroid receptor coactivators; unfolded protein response; breast cancer; PERK; NCOA3 Received: November 03, 2017 Accepted: February 01, 2018 Published: February 08, 2018 ABSTRACT Nuclear receptor coactivators (NCOAs) function as coactivators for nuclear receptors as well as several other transcription factors and potentiate their transcriptional activity. NCOAs play an important role in biology of hormone-dependent and -independent cancers. MCB-613 is a recently described, small molecule stimulator of NCOAs and anti-neoplastic compound that leads to the death of tumour cells due to increased cellular stress. In the present study we investigated the molecular mechanism of MCB-613-induced cell death. We report that absence of NCOA3 leads to compromised activation of PERK signalling pathway during unfolded protein response (UPR). We found that chemical and genetic inhibition of NCOA3 attenuated the expression of PERK at mRNA and protein level. We show that loss of NCOA3 renders cells hypersensitive to UPR induced cell death. Our results show that MCB-613 induced cell death is attenuated in NCOA3 knockout HeLa cells and MCB-613 leads to enhanced PERK signalling in wild-type HeLa cells. The knockdown of PERK provides resistance to MCB-613 mediated cell death while knockdown of XBP1 and ATF6 have no such effect. Our results suggest that hyperstimulation of NCOA3 by MCB-613 induces cell death by evoking constitutive PERK signalling. Taken together our results point to NCOA3 as an important determinant in regulating cell fate during ER stress, with too little and too much NCOA3 both producing deleterious effects.

AIM To identify glycosylation-related genes in the HT29 derivative cell line, HT29-MTX-E12, showing differential expression on infection with Helicobacter pylori (H. pylori). METHODS Polarised HT29-MTX-E12 cells were infected for 24 h with H. pylori strain 26695. After infection RNA was isolated from both infected and non-infected host cells. Sufficient infections were carried out to provide triplicate samples for microarray analysis and for qRT-PCR analysis. RNA was isolated and hybridised to Affymetrix arrays. Analysis of microarray data identified genes significantly differentially expressed upon infection. Genes were grouped into gene ontology functional categories. Selected genes associated with host glycan structure (glycosyltransferases, hydrolases, lectins, mucins) were validated by real-time qRT-PCR analysis. RESULTS Infection of host cells was confirmed by the isolation of live bacteria after 24 h incubation and by PCR amplification of bacteria-specific genes from the host cell RNA. H. pylori do not survive incubation under the adopted culture conditions unless they associate with the adherent mucus layer of the host cell. Microarray analysis identified a total of 276 genes that were significantly differentially expressed (P < 0.05) upon H. pylori infection and where the fold change in expression was greater than 2. Six of these genes are involved in glycosylation-related processes. Real-time qRT-PCR demonstrated significant downregulation (1.8-fold, P < 0.05) of the mucin MUC20. REG4 was heavily expressed and significantly downregulated (3.1-fold, P < 0.05) upon infection. Gene ontology analysis was consistent with previous studies on H. pylori infection. CONCLUSION Gene expression data suggest that infection with H. pylori causes a decrease in glycan synthesis, resulting in shorter and simpler glycan structures.

Mycobacterium indicus pranii (MIP) is a potent vaccine candidate against tuberculosis (TB) as it has demonstrated significant protection in animal models of tuberculosis as well as in clinical trials. Higher protective efficacy of MIP against TB as compared to BCG provoked the efforts to gain insight into the molecular mechanisms underlying MIP mediated protection against Mycobacterium tuberculosis (M.tb). Autophagy, initially described as a cell survival mechanism during starvation, also plays a key role in host resistance to M.tb. Virulent mycobacteria like M.tb, suppresses host autophagy response to increase its survival in macrophages. Since mycobacterial species have been shown to vary widely in their autophagy-inducing properties, in the present study, we examined the autophagy inducing efficacy of MIP and its role in MIP-mediated protection against M.tb. MIP was found to be potent inducer of autophagy in macrophages. Induced autophagy was responsible for reversal of the phagosome maturation block and phagolysosome fusion inhibition in M.tb infected macrophages, which ultimately lead to significantly enhanced clearance of M.tb from the macrophages. This is an important study which further delineated the underlying mechanisms for significant immunotherapeutic activity observed in TB patients / animal models of tuberculosis, given MIP therapy along with chemotherapy.

The endoplasmic reticulum (ER) responds to changes in intracellular homeostasis through activation of the unfolded protein response (UPR). UPR can facilitate the restoration of cellular homeostasis, via the concerted activation of three ER stress sensors, namely IRE1, PERK and ATF6. Global approaches in several cellular contexts have revealed that UPR regulates the expression of many miRNAs that play an important role in the regulation of life and death decisions during UPR. Here we show that expression of miR-424(322)-503 cluster is downregulated during UPR. IRE1 inhibitor (4 μ8C) and deficiency of XBP1 had no effect on downregulation of miR-424(322)-503 during UPR. Treatment of cells with CCT030312, a selective activator of EIF2AK3/PERK signalling, leads to the downregulation of miR-424(322)-503 expression. The repression of miR-424(322)-503 cluster during conditions of ER stress is compromised in PERK-deficient MEFs. miR-424 regulates the expression of ATF6 via a miR-424 binding site in its 3′ UTR and attenuates the ATF6 transcriptional activity during UPR. Further miR-424 had no effect on IRE1-XBP1 axis but enhanced the regulated IRE1-dependent decay (RIDD). Our results suggest that miR-424 constitutes an obligatory fine-tuning mechanism where PERK-mediated downregulation of miR-424(322)-503 cluster regulates optimal activation of IRE1 and ATF6 during conditions of ER stress.

The endoplasmic reticulum (ER) is the site of folding for membrane and secreted proteins. Accumulation of unfolded or misfolded proteins in the ER triggers the unfolded protein response (UPR). The UPR can promote survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. However, when ER stress is acute or prolonged cells undergo apoptosis. In this study we sought to determine the effect of globally compromised microRNA biogenesis on the UPR and ER stress-induced apoptosis. Here we report the role of Dicer-dependent miRNA biogenesis during the UPR and ER stress-induced apoptosis. We show that ER stress-induced caspase activation and apoptosis is attenuated in Dicer deficient fibroblasts. ER stress-mediated induction of GRP78, the key ER resident chaperone, and also HERP, an important component of ER-associated degradation, are significantly increased in Dicer deficient cells. Expression of the BCL-2 family members BIM and MCL1 were significantly higher in Dicer-null fibroblasts. However, ER stress-mediated induction of pro-apoptotic BH3 only protein BIM was compromised in Dicer mutant cells.These observations demonstrate key roles for Dicer in the UPR and implicate miRNAs as critical components of UPR.

Activation of the unfolded protein response sensor PKR-like endoplasmic reticulum kinase (Perk) attenuates endoplasmic reticulum (ER) stress levels. Conversantly, if the damage is too severe and ER function cannot be restored, this signaling branch triggers apoptosis. Bcl-2 homology 3-only family member Bim is essential for ER stress-induced apoptosis. However, the regulatory mechanisms controlling Bim activation under ER stress conditions are not well understood. Here, we show that downregulation of the miR-106b-25 cluster contributes to ER stress-induced apoptosis and the upregulation of Bim. Hypericin-mediated photo-oxidative ER damage induced Perk-dependent cell death and led to a significant decrease in the levels of miRNAs belonging to miR-106b-25 cluster in wild-type (WT) but not in Perk(- / -) MEFs. Further, we show that expression of miR-106b-25 and Mcm-7 (host gene of miR-106b-25) is co-regulated through the transcription factors Atf4 (activating transcription factor 4) and Nrf2 (nuclear factor-erythroid-2-related factor 2). ER stress increased the activity of WT Bim 3'UTR (untranslated region) construct but not the miR-106b-25 recognition site-mutated Bim 3'UTR construct. Overexpression of miR-106b-25 cluster inhibits ER stress-induced cell death in WT but did not confer any further protection in Bim-knockdown cells. Further, we show downregulation in the levels of miR-106b-25 cluster in the symptomatic SOD1(G86R) transgenic mice. Our results suggest a molecular mechanism whereby repression of miR-106b-25 cluster has an important role in ER stress-mediated increase in Bim and apoptosis. Cell Death and Disease (2012) 3, e333; doi:10.1038/cddis.2012.74; published online 28 June 2012

Summary Stem cell-based in vitro models of embryonic development have been established over the last decade. Such model systems recapitulate aspects of gametogenesis, early embryonic development, or organogenesis. They enable experimental approaches that have not been possible previously and have the potential to greatly reduce the number of animals required for research. However, each model system has its own limitations, with certain aspects, such as morphogenesis and spatiotemporal control of cell fate decisions, diverging from the in vivo counterpart. Targeted bioengineering approaches to provide defined instructive external signals or to modulate internal cellular signals could overcome some of these limitations. Here, we present the latest technical developments and discuss how bioengineering can further advance the optimization and external control of stem cell-based embryo-like structures (ELSs). In vitro models combined with sophisticated bioengineering tools will enable an even more in-depth analysis of embryonic development in the future., In this review, Lutolf and coworkers discuss how bioengineering approaches can further advance the optimization and external control of stem cell-based embryo-like structures. In vitro models of embryonic development combined with sophisticated bioengineering tools will enable an even more in-depth analysis of embryonic development in the future.