Non-cell Autonomous Manner Research Articles

MiR-148a functions to suppress metastasis and serves as a prognostic indicator in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) presents a major challenge in the clinic due to its lack of reliable prognostic markers and targeted therapies. Accumulating evidence strongly supports the notion that microRNAs (miRNAs) are involved in tumorigenesis and could serve as biomarkers for diagnostic purposes. To identify miRNAs that functionally suppress metastasis of TNBC, we employed a concerted approach with selecting miRNAs that display differential expression profiles from bioinformatic analyses of breast cancer patient databases and validating top candidates with functional assays using breast cancer cell lines and mouse models. We have found that miR-148a exhibits properties as a tumor suppressor as its expression is inversely correlated with the ability of both human and mouse breast cancer cells to colonize the lung in mouse xenograft tumor models. Mechanistically, miR-148a appears to suppress the extravasation process of cancer cells, likely by targeting two genes WNT1 and NRP1 in a cell non-autonomous manner. Importantly, lower expression of miR-148a is detected in higher-grade tumor samples and correlated with increased likelihood to develop metastases and poor prognosis in subsets of breast cancer patients, particularly those with TNBC. Thus, miR-148a is functionally defined as a suppressor of breast cancer metastasis and may serve as a prognostic biomarker for this disease.

Overexpression of Peptide-Encoding OsCEP6.1 Results in Pleiotropic Effects on Growth in Rice (O. sativa).

Plant peptide hormones play an important role in regulating plant developmental programs via cell-to-cell communication in a non-cell autonomous manner. To characterize the biological relevance of C-TERMINALLY ENCODED PEPTIDE (CEP) genes in rice, we performed a genome-wide search against public databases using a bioinformatics approach and identified six additional CEP members. Expression analysis revealed a spatial-temporal pattern of OsCEP6.1 gene in different tissues and at different developmental stages of panicle. Interestingly, the expression level of the OsCEP6.1 was also significantly up-regulated by exogenous cytokinin. Application of a chemically synthesized 15-amino acid OsCEP6.1 peptide showed that OsCEP6.1 had a negative role in regulating root and seedling growth, which was further confirmed by transgenic lines. Furthermore, the constitutive expression of OsCEP6.1 was sufficient to lead to panicle architecture and grain size variations. Scanning electron microscopy analysis revealed that the phenotypic variation of OsCEP6.1 overexpression lines resulted from decreased cell size but not reduced cell number. Moreover, starch accumulation was not significantly affected. Taken together, these data suggest that the OsCEP6.1 peptide might be involved in regulating the development of panicles and grains in rice.

Epithelial Control of Gut-Associated Lymphoid Tissue Formation through p38α-Dependent Restraint of NF-κB Signaling.

The protein kinase p38α mediates cellular responses to environmental and endogenous cues that direct tissue homeostasis and immune responses. Studies of mice lacking p38α in several different cell types have demonstrated that p38α signaling is essential to maintaining the proliferation-differentiation balance in developing and steady-state tissues. The mechanisms underlying these roles involve cell-autonomous control of signaling and gene expression by p38α. In this study, we show that p38α regulates gut-associated lymphoid tissue (GALT) formation in a noncell-autonomous manner. From an investigation of mice with intestinal epithelial cell-specific deletion of the p38α gene, we find that p38α serves to limit NF-κB signaling and thereby attenuate GALT-promoting chemokine expression in the intestinal epithelium. Loss of this regulation results in GALT hyperplasia and, in some animals, mucosa-associated B cell lymphoma. These anomalies occur independently of luminal microbial stimuli and are most likely driven by direct epithelial-lymphoid interactions. Our study illustrates a novel p38α-dependent mechanism preventing excessive generation of epithelial-derived signals that drive lymphoid tissue overgrowth and malignancy.

MicroRNA and Metastasis.

Noncoding RNAs are important regulatory molecules of cellular processes. MicroRNAs (miRNAs) are small noncoding RNAs that bind to complementary sequences in the 3' untranslated region of target mRNAs, leading to degradation of the target mRNAs and/or inhibition of their translation. Some miRNAs are essential for normal animal development; however, many other miRNAs are dispensable for development but play a critical role in pathological conditions, including tumorigenesis and metastasis. miRNA genes often reside at fragile chromosome sites and are deregulated in cancer. Some miRNAs function as oncogenes or tumor suppressors, collectively termed "oncomirs." Specific metastasis-regulating miRNAs, collectively termed "metastamirs," govern molecular processes and pathways in malignant progression in either a tumor cell-autonomous or a cell-nonautonomous manner. Recently, exosome-transferred miRNAs have emerged as mediators of the tumor-stroma cross talk. In this chapter, we focus on the functions, mechanisms of action, and therapeutic potential of miRNAs, particularly oncomirs and metastamirs.

PbWoxT1 mRNA from pear (Pyrus betulaefolia) undergoes long-distance transport assisted by a polypyrimidine tract binding protein.

Little is known about the mechanisms by which mRNAs are transported over long distances in the phloem between the rootstock and the scion in grafted woody plants. We identified an mRNA in the pear variety 'Du Li' (Pyrus betulaefolia) that was shown to be transportable in the phloem. It contains a WUSCHEL-RELATED HOMEOBOX (WOX) domain and was therefore named Wox Transport 1 (PbWoxT1). A 548-bp fragment of PbWoxT1 is critical in long-distance transport. PbWoxT1 is rich in CUCU polypyrimidine domains and its mRNAs interact with a polypyrimidine tract binding protein, PbPTB3. Furthermore, the expression of PbWoxT1 significantly increased in the stems of wild-type (WT) tobacco grafted onto the rootstocks of PbWoxT1 or PbPTB3 co-overexpressing lines, but this was not the case in WT plants grafted onto PbWoxT1 overexpressing rootstocks, suggesting that PbPTB3 mediates PbWoxT1 mRNA long-distance transport. We provide novel information that adds a new mechanism with which to explain the noncell-autonomous manner of WOX gene function, which enriches our understanding of how WOX genes work in fruit trees and other species.

Tangential migration of glutamatergic neurons and cortical patterning during development: Lessons from Cajal-Retzius cells.

Tangential migration is a mode of cell movement, which in the developing cerebral cortex, is defined by displacement parallel to the ventricular surface and orthogonal to the radial glial fibers. This mode of long-range migration is a strategy by which distinct neuronal classes generated from spatially and molecularly distinct origins can integrate to form appropriate neural circuits within the cortical plate. While it was previously believed that only GABAergic cortical interneurons migrate tangentially from their origins in the subpallial ganglionic eminences to integrate in the cortical plate, it is now known that transient populations of glutamatergic neurons also adopt this mode of migration. These include Cajal-Retzius cells (CRs), subplate neurons (SPs), and cortical plate transient neurons (CPTs), which have crucial roles in orchestrating the radial and tangential development of the embryonic cerebral cortex in a noncell-autonomous manner. While CRs have been extensively studied, it is only in the last decade that the molecular mechanisms governing their tangential migration have begun to be elucidated. To date, the mechanisms of SPs and CPTs tangential migration remain unknown. We therefore review the known signaling pathways, which regulate parameters of CRs migration including their motility, contact-redistribution and adhesion to the pial surface, and discuss this in the context of how CR migration may regulate their signaling activity in a spatial and temporal manner. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 847-881, 2016.

Systemic Inflammation Recruits Ccr7+ Dendritric-Biased Granulocyte-Macrophage Progenitors to Lymphatic Circulation in a Non-Canonical Traf6-Dependent Manner

A small fraction of hematopoietic stem and progenitor cells (HSPCs) is cyclically released into the bloodstream from bone marrow (BM). The existence of HSCP-lymphatic-blood circulation with the potential to give rise to extramedullary tissue-resident myeloid cells has been described. However, the functional role and underlying mechanisms of this circulation are not known. We hypothesized that inflammation may be a mediator of HSPC mobilization to lymph. In order to determine if inflammation was related to increased circulation of HSPCs through lymph, we analyzed the HSPC content in lymph nodes (LN) of patients with lymphadenitis. Analysis of CFU and side population (SP+) cell content confirmed that LNs from patients with reactive lymphadenitis and patients with inflammatory Hodgkin's disease contained ~2-fold higher HSPCs than in patients diagnosed of non-Hodgkin's lymphoma. To identify the pattern and mechanisms that regulate HSPCs during inflammation. We analyzed the content of HSPCs in blood (PB), BM, LN, thoracic duct (TD) and other organs after systemic administration of lipopolysaccharide (LPS) and compared with the normal circadian migratory rhythms in control animals (PBS). Mobilization of BM myeloid progenitors (mostly granulo-macrophage progenitors-GMPs, but not stem cells), to LN and TD peaked as early as three hours after LPS administration, and followed a very different pattern than the mobilization kinetics in PB. By using 3D reconstruction of confocal microscopy imaging of complete LN from lymphatic endothelium reporter mice (Lyve1Cre-eGFP), we localized all myeloid progenitors in the mantle zone of secondary follicles. We note that they did not enter the follicle germ centers. To determine the molecular mechanisms at play to induce HSPC mobilization to the LN upon LPS administration, we analyzed whether the recruitment of HSPCs in LN required Traf6, a mediator downstream of the LPS/TLR4 signaling pathway. Inducible deficiency of Traf6 driven by Mx1-Cre recombinase completely abolished the migration of myeloid progenitors to LN, but not to PB, induced by LPS as compared with their Mx1-Cre;Wt littermates indicating that the mechanism controlling HSPC recruitment to the LN was distinct from the one controlling HSPC migration to PB. Using a combination of in vivo and in vitro assays, we found that Traf6 activity regulates HSPC migration in a non-cell autonomous manner that depends on its expression in a small (~1%) fraction of non-progenitor LN myeloid cells expressing high levels of Ccl19. In vivo neutralization of Ccr7, the receptor for Ccl19, results in abrogation of myeloid progenitor mobilization to LN. GMPs migrating to LN were biased to differentiate into dendritic cells within 7 days post-migration. Using Cx3cr1-GFP transgenic mice as macrophage-dendritic cell progenitor (MDP) reporters, we found that the vast majority of GMPs recruited to the LN were MDPs, and thus already poised to DC differentiation. Finally, a combination of genetic and pharmacological approaches revealed that Traf6 signaling effects are NFkB independent but dependent upon Irak1/4, Ucb13 and IKKβ resulting in SNAP23 phosphorylation and exocytosis of pre-formed cytokines from LN myeloid cells. This study identifies the cellular and molecular basis of inflammation dependent migration of DC progenitors and suggests that the mobilization of HSPCs from BM to LN results in homeostatic replenishment of highly specialized antigen presenting cells. DisclosuresNo relevant conflicts of interest to declare.

Genetic Screen Reveals Link between the Maternal Effect Sterile Gene mes-1 and Pseudomonas aeruginosa-induced Neurodegeneration in Caenorhabditis elegans

Increasing evidence indicates that immune responses to microbial infections may contribute to neurodegenerative diseases. Here, we show that Pseudomonas aeruginosa infection of Caenorhabditis elegans causes a number of neural changes that are hallmarks of neurodegeneration. Using an unbiased genetic screen to identify genes involved in the control of P. aeruginosa-induced neurodegeneration, we identified mes-1, which encodes a receptor tyrosine kinase-like protein that is required for unequal cell divisions in the early embryonic germ line. We showed that sterile but not fertile mes-1 animals were resistant to neurodegeneration induced by P. aeruginosa infection. Similar results were observed using animals carrying a mutation in the maternal effect gene pgl-1, which is required for postembryonic germ line development, and the germ line-deficient strains glp-1 and glp-4. Additional studies indicated that the FOXO transcription factor DAF-16 is required for resistance to P. aeruginosa-induced neurodegeneration in germ line-deficient strains. Thus, our results demonstrate that P. aeruginosa infection results in neurodegeneration phenotypes in C. elegans that are controlled by the germ line in a cell-nonautonomous manner.

Sall1 in renal stromal progenitors non-cell autonomously restricts the excessive expansion of nephron progenitors.

The mammalian kidney develops from reciprocal interactions between the metanephric mesenchyme and ureteric bud, the former of which contains nephron progenitors. The third lineage, the stroma, fills up the interstitial space and is derived from distinct progenitors that express the transcription factor Foxd1. We showed previously that deletion of the nuclear factor Sall1 in nephron progenitors leads to their depletion in mice. However, Sall1 is expressed not only in nephron progenitors but also in stromal progenitors. Here we report that specific Sall1 deletion in stromal progenitors leads to aberrant expansion of nephron progenitors, which is in sharp contrast with a nephron progenitor-specific deletion. The mutant mice also exhibited cystic kidneys after birth and died before adulthood. We found that Decorin, which inhibits Bmp-mediated nephron differentiation, was upregulated in the mutant stroma. In contrast, the expression of Fat4, which restricts nephron progenitor expansion, was reduced mildly. Furthermore, the Sall1 protein binds to many stroma-related gene loci, including Decorin and Fat4. Thus, the expression of Sall1 in stromal progenitors restricts the excessive expansion of nephron progenitors in a non-cell autonomous manner, and Sall1-mediated regulation of Decorin and Fat4 might at least partially underlie the pathogenesis.

Identification of an EGFRvIII-JNK2-HGF/c-Met-Signaling Axis Required for Intercellular Crosstalk and Glioblastoma Multiforme Cell Invasion.

Glioblastoma multiforme (GBM) is the most aggressive and common form of adult brain cancer. Current therapeutic strategies include surgical resection, followed by radiotherapy and chemotherapy. Despite such aggressive multimodal therapy, prognosis remains poor, with a median patient survival of 14 months. A proper understanding of the molecular drivers responsible for GBM progression are therefore necessary to instruct the development of novel targeted agents and enable the design of effective treatment strategies. Activation of the c-Jun N-terminal kinase isoform 2 (JNK2) is reported in primary brain cancers, where it associates with the histologic grade and amplification of the epidermal growth factor receptor (EGFR). In this manuscript, we demonstrate an important role for JNK2 in the tumor promoting an invasive capacity of EGFR variant III, a constitutively active mutant form of the receptor commonly found in GBM. Expression of EGFR variant III induces transactivation of JNK2 in GBM cells, which is required for a tumorigenic phenotype in vivo. Furthermore, JNK2 expression and activity is required to promote increased cellular invasion through stimulation of a hepatocyte growth factor-c-Met signaling circuit, whereby secretion of this extracellular ligand activates the receptor tyrosine kinase in both a cell autonomous and nonautonomous manner. Collectively, these findings demonstrate the cooperative and parallel activation of multiple RTKs in GBM and suggest that the development of selective JNK2 inhibitors could be therapeutically beneficial either as single agents or in combination with inhibitors of EGFR and/or c-Met.

Abstract 3262: Mitochondrial haplotype effects on tumor formation and metastasis are both cell autonomous and non-cell autonomous

Abstract Increasing data support roles for mitochondrial genomes in complex diseases, including cancer. We hypothesize that primary tumor formation and metastasis can arise from inherited mitochondrial differences. To test directly the role of mitochondrial DNA (mtDNA) in mammary cancer tumorigenicity and metastasis, we generated Mitochondrial Nuclear Exchange (MNX) mice. This unique animal model is created by moving the nucleus from an oocyte of one strain into an enucleated oocyte of a different strain. By exchanging the nucleus of mouse strains promoting or inhibiting metastatic efficiency, mtDNA effects can be distinguished from phenotypes which would occur due to nuclear admixing. To determine if a change in the mtDNA background impacts metastasis in a cell autonomous manner, two FVB transgenic mouse strains encoding either Her2 or PyMT oncogenes were crossed with MNX mice with FVB nuclear DNA and mtDNA from either BALB/cJ or C57BL6J strains. The mtDNA were chosen because of higher or lower metastatic efficiency, respectively (PMID9679770, PMID16491073). Latency of mammary tumor formation in MNX mice with C57BL/6 mtDNA is longer for both Her2 and PyMT. Lung metastases are smaller in C57BL6 but larger in BALB/c MNX crosses with the PyMT. Studies measuring metastasis efficiency in the MNX crosses with Her2 are still in progress. To determine whether the mitochondrial haplotype alters tumorigenicity or metastasis in a non-cell autonomous manner, syngeneic tumor cells were injected orthotopically and ectopically (i.v.). Tumor formation and metastasis differ in a tumor and mtDNA-dependent manner. For example, E0771 forms significantly more lung metastases in C57BL/6n:C3H/HeNmt mice compared to controls. To explore underlying mechanisms, metabolic differences were observed in MNX and matched wild type mouse embryonic fibroblasts using the Seahorse bioanalyzer. Conclusion: mtDNA affects mammary cancer development and progression via both genetic and non-cell autonomous mechanisms in the tumor microenvironment. Support: Susan G. Komen for the Cure (SAC11037), Natl Fndn Cancer Res, Steiner Family Fund for Metastasis Research, Kansas Bioscience Authority, CA134981, P30-CA168524 Citation Format: Amanda E. Brinker, Carolyn J. Vivian, Kyle P. Feeley, Scott W. Ballinger, Danny R. Welch. Mitochondrial haplotype effects on tumor formation and metastasis are both cell autonomous and non-cell autonomous. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3262. doi:10.1158/1538-7445.AM2015-3262

Epithelial microRNA‐9a regulates dendrite growth through Fmi‐Gq signaling in Drosophila sensory neurons

microRNA-9 (miR-9) is highly expressed in the nervous system across species and plays essential roles in neurogenesis and axon growth; however, little is known about the mechanisms that link miR-9 with dendrite growth. Using an in vivo model of Drosophila class I dendrite arborization (da) neurons, we show that miR-9a, a Drosophila homolog of mammalian miR-9, downregulates the cadherin protein Flamingo (Fmi) thereby attenuating dendrite development in a non-cell autonomous manner. In miR-9a knockout mutants, the dendrite length of a sensory neuron ddaE was significantly increased. Intriguingly, miR-9a is specifically expressed in epithelial cells but not in neurons, thus the expression of epithelial but not neuronal Fmi is greatly elevated in miR-9a mutants. In contrast, overexpression of Fmi in the neuron resulted in a reduction in dendrite growth, suggesting that neuronal Fmi plays a suppressive role in dendrite growth, and that increased epithelial Fmi might promote dendrite growth by competitively binding to neuronal Fmi. Fmi has been proposed as a G protein-coupled receptor (GPCR), we find that neuronal G protein Gαq (Gq), but not Go, may function downstream of Fmi to negatively regulate dendrite growth. Taken together, our results reveal a novel function of miR-9a in dendrite morphogenesis. Moreover, we suggest that Gq might mediate the intercellular signal of Fmi in neurons to suppress dendrite growth. Our findings provide novel insights into the complex regulatory mechanisms of microRNAs in dendrite development, and further reveal the interplay between the different components of Fmi, functioning in cadherin adhesion and GPCR signalling.

Genetic reduction of mitochondrial complex I function does not lead to loss of dopamine neurons in vivo

Inhibition of mitochondrial complex I activity is hypothesized to be one of the major mechanisms responsible for dopaminergic neuron death in Parkinson's disease. However, loss of complex I activity by systemic deletion of the Ndufs4 gene, one of the subunits comprising complex I, does not cause dopaminergic neuron death in culture. Here, we generated mice with conditional Ndufs4 knockout in dopaminergic neurons (Ndufs4 conditional knockout mice [cKO]) to examine the effect of complex I inhibition on dopaminergic neuron function and survival during aging and on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in vivo. Ndufs4 cKO mice did not show enhanced dopaminergic neuron loss in the substantia nigra pars compacta or dopamine-dependent motor deficits over the 24-month life span. These mice were just as susceptible to MPTP as control mice. However, compared with control mice, Ndufs4 cKO mice exhibited an age-dependent reduction of dopamine in the striatum and increased α-synuclein phosphorylation in dopaminergic neurons of the substantia nigra pars compacta. We also used an inducible Ndufs4 knockout mouse strain (Ndufs4 inducible knockout) in which Ndufs4 is conditionally deleted in all cells in adult to examine the effect of adult onset, complex I inhibition on MPTP sensitivity of dopaminergic neurons. The Ndufs4 inducible knockout mice exhibited similar sensitivity to MPTP as control littermates. These data suggest that mitochondrial complex I inhibition in dopaminergic neurons does contribute to dopamine loss and the development of α-synuclein pathology. However, it is not sufficient to cause cell-autonomous dopaminergic neuron death during the normal life span of mice. Furthermore, mitochondrial complex I inhibition does not underlie MPTP toxicity in vivo in either cell autonomous or nonautonomous manner. These results provide strong evidence that inhibition of mitochondrial complex I activity is not sufficient to cause dopaminergic neuron death during aging nor does it contribute to dopamine neuron toxicity in the MPTP model of Parkinson's disease. These findings suggest the existence of alternative mechanisms of dopaminergic neuron death independent of mitochondrial complex I inhibition.

MeCP2 in the rostral striatum maintains local dopamine content critical for psychomotor control.

Methyl-CpG binding protein 2 (MeCP2) is a chromatin regulator highly expressed in mature neurons. Mutations of MECP2 gene cause >90% cases of Rett syndrome, a neurodevelopmental disorder featured by striking psychomotor dysfunction. In Mecp2-null mice, the motor deficits are associated with reduction of dopamine content in the striatum, the input nucleus of basal ganglia mostly composed of GABAergic neurons. Here we investigated the causal role of MeCP2 in modulation of striatal dopamine content and psychomotor function. We found that mice with selective removal of MeCP2 in forebrain GABAergic neurons, predominantly in the striatum, phenocopied Mecp2-null mice in dopamine deregulation and motor dysfunction. Selective expression of MeCP2 in the striatum preserved dopamine content and psychomotor function in both males and females. Notably, the dopamine deregulation was primarily confined to the rostral striatum, and focal deletion or reactivation of MeCP2 expression in the rostral striatum through adeno-associated virus effectively disrupted or restored dopamine content and locomotor activity, respectively. Together, these findings demonstrate that striatal MeCP2 maintains local dopamine content in a non-cell autonomous manner in the rostral striatum and that is critical for psychomotor control.

K-Ras, Intestinal Homeostasis and Colon Cancer

Activating Ras mutations, present in about 20% of human cancers, compromise the GTPase activity of Ras and therefore trigger accumulation of Ras in the GTP-bound state. Among the three family members, K-Ras, H-Ras and N-Ras, K-Ras is the most frequently mutated gene, with 30-50% of colon cancer patients harboring activating K-Ras mutations. Oncogenic mutations of K-Ras have been found at codons 12, 13, 61 and 146. Activation of Ras triggers constitutive activation of signaling pathways, including the MAPK and AKT pathways, which allows tumor cells to proliferate in the absence of growth factors and increases their survival. In addition, activated Ras triggers inflammation and thus promotes tumor progression in a cell non-autonomous manner. The presence of K-Ras mutations not only has prognostic value, but it also predicts the responsiveness of colon cancer patients to inhibitors of EGFR signaling.

Non-cell autonomous and non-catalytic activities of ATX in the developing brain.

The intricate formation of the cerebral cortex requires a well-coordinated series of events, which are regulated at the level of cell-autonomous and non-cell autonomous mechanisms. Whereas cell-autonomous mechanisms that regulate cortical development are well-studied, the non-cell autonomous mechanisms remain poorly understood. A non-biased screen allowed us to identify Autotaxin (ATX) as a non-cell autonomous regulator of neural stem cells. ATX (also known as ENPP2) is best known to catalyze lysophosphatidic acid (LPA) production. Our results demonstrate that ATX affects the localization and adhesion of neuronal progenitors in a cell autonomous and non-cell autonomous manner, and strikingly, this activity is independent from its catalytic activity in producing LPA.

The heparan sulfate-modifying enzyme glucuronyl C5-epimerase HSE-5 controls Caenorhabditis elegans Q neuroblast polarization during migration

Directional cell migration is fundamental for neural development, and extracellular factors are pivotal for this process. Heparan sulfate proteoglycans (HSPGs) that carry long chains of differentially modified sugar residues contribute to extracellular matrix; however, the functions of HSPG in guiding cell migration remain elusive. Here, we used the Caenorhabditis elegans mutant pool from the Million Mutation Project and isolated a mutant allele of the heparan sulfate-modifying enzyme glucuronyl C5-epimerase HSE-5. Loss-of-function of this enzyme resulted in defective Q neuroblast migration. We showed that hse-5 controlled Q cell migration in a cell non-autonomous manner. By performing live cell imaging in hse-5 mutant animals, we found that hse-5 controlled initial polarization during Q neuroblast migration. Furthermore, our genetic epistasis analysis demonstrated that lon-2 might act downstream of hse-5. Finally, rescue of the hse-5 mutant phenotype by expression of human and mouse hse-5 homologs suggested a conserved function for this gene in neural development. Taken together, our results indicated that proper HSPG modification in the extracellular matrix by HSE-5 is essential for neuroblast polarity during migration.

Translational horizons in the tumor microenvironment: harnessing breakthroughs and targeting cures.

Chemotherapy and targeted therapy have opened new avenues in clinical oncology. However, there is a lack of response in a substantial percentage of cancer patients and diseases frequently relapse in those who even initially respond. Resistance is, at present, the major barrier to conquering cancer, the most lethal age-related pathology. Identification of mechanisms underlying resistance and development of effective strategies to circumvent treatment pitfalls thereby improving clinical outcomes remain overarching tasks for scientists and clinicians. Growing bodies of data indicate that stromal cells within the genetically stable but metabolically dynamic tumor microenvironment confer acquired resistance against anticancer therapies. Further, treatment itself activates the microenvironment by damaging a large population of benign cells, which can drastically exacerbate disease conditions in a cell nonautonomous manner, and such off-target effects should be well taken into account when establishing future therapeutic rationale. In this review, we highlight relevant biological mechanisms through which the tumor microenvironment drives development of resistance. We discuss some unsolved issues related to the preclinical and clinical trial paradigms that need to be carefully devised, and provide implications for personalized medicine. In the long run, an insightful and accurate understanding of the intricate signaling networks of the tumor microenvironment in pathological settings will guide the design of new clinical interventions particularly combinatorial therapies, and it might help overcome, or at least prevent, the onset of acquired resistance.

Long distance movement of an Arabidopsis Translationally Controlled Tumor Protein (AtTCTP2) mRNA and protein in tobacco.

Translationally Controlled Tumor Protein (TCTP) is an almost ubiquitous protein found in eukaryotes, fundamental for the regulation of development and general growth. The multiple functions of TCTP have been inferred from its involvement in several cell pathways, but the specific function of TCTP is still not known in detail. On the other hand, TCTP seems to respond to a plethora of external signals, and appears to be regulated at the transcriptional and/or translational levels by mechanisms yet to be determined. In the present work, we analyzed the capacity of AtTCTP2 gene products (mRNA and protein) to translocate long distance through tobacco heterografts (transgenic/WT and WT/transgenic). The results indicate that both AtTCTP2 mRNA and protein are capable of moving long distance in both directions (stock-scion and scion-stock) with a tendency for movement from source to sink tissue (stock to scion). Interestingly, aerial roots emerged only in heterografts where the protein was detected in both stock and scion, suggesting a correlation between the presence of AtTCTP2 and aerial root appearance. More detailed analysis showed that these aerial roots harbored the transgene and expressed both transcript and protein. In addition, the protein localization pattern in transgenic aerial and primary roots was basically the same, indicating specific nuclear destination in roots, but also in leaves. These findings provide an approach to understand the role of long-distance movement in the function of plant TCTPs, supporting the notion that some of these act in a non-cell autonomous manner, as the human counterpart, the Histamine Releasing Factor (HRF).

The thymic microenvironment differentially regulates development and trafficking of invariant NKT cell sublineages.

The regulatory role of the thymic microenvironment during trafficking and differentiation of the invariant NKT (iNKT) cell lineage remains poorly understood. In this study, we show that fractalkine receptor expression marks emigrating subpopulations of the NKT1, NKT2, and NKT17 sublineages in the thymus and peripheral organs of naive mice. Moreover, NKT1 sublineage cells can be subdivided into two subsets, namely NKT1(a) and NKT1(b), which exhibit distinct developmental and tissue-specific distribution profiles. More specifically, development and trafficking of the NKT1(a) subset are selectively dependent upon lymphotoxin (LT)α1β2-LTβ receptor-dependent differentiation of thymic stroma, whereas the NKT1(b), NKT2, and NKT17 sublineages are not. Furthermore, we identify a potential cellular source for LTα1β2 during thymic organogenesis, marked by expression of IL-7Rα, which promotes differentiation of the NKT1(a) subset in a noncell-autonomous manner. Collectively, we propose a mechanism by which thymic differentiation and retention of the NKT1 sublineage are developmentally coupled to LTα1β2-LTβ receptor-dependent thymic organogenesis.