The Jak/STAT pathway in model organisms: emerging roles in cell movement

Circular RNAs and the JAK/STAT pathway: New frontiers in cancer therapeutics

Circular RNAs, known as circRNAs, have drawn more attention to cancer biology in the last few years. Novel functions of circRNAs in cancer therapy open promising prospects for personalized medicine. This review focuses on the molecular properties and potential of circRNAs as biomarkers or therapeutic targets in cancer treatment. Unique properties of circular RNAs associated with a circular form provide stability and resilience to RNA exonuclease degradation. Circular RNAs' most important characteristic is that they are involved in the JAK/STAT pathway associated with oncogenesis. Notably, their deregulation has been reported in multiple carcinomas due to involvement in JAK/STAT signaling cascade modulation. Increased knowledge about circRNAs' interaction with the JAK/STAT pathway leads to the emergence of new possibilities for targeted cancer therapy. In addition, since circRNAs demonstrate tissue-relatedness of expression, they may be a reliable biomarker for predicting and diagnosing cancer. With the development of new technologies for targeting circRNAs, novel therapeutics can be produced that offer more personalized cancer treatment options based on the nature of the patient. The present review explores the exciting prospects of circRNAs for transforming cancer treatment into personalized medicine. It describes the current understanding of circRNA biology, its relationship to tumorigenesis, and possible targeting methods.

JAK-STAT signaling maintains homeostasis in T cells and macrophages

Immune cells need to sustain a state of constant alertness over a lifetime. Yet, little is known about the regulatory processes that control the fluent and fragile balance that is called homeostasis. Here we demonstrate that JAK-STAT signaling, beyond its role in immune responses, is a major regulator of immune cell homeostasis. We investigated JAK-STAT-mediated transcription and chromatin accessibility across 12 mouse models, including knockouts of all STAT transcription factors and of the TYK2 kinase. Baseline JAK-STAT signaling was detected in CD8+ T cells and macrophages of unperturbed mice-but abrogated in the knockouts and in unstimulated immune cells deprived of their normal tissue context. We observed diverse gene-regulatory programs, including effects of STAT2 and IRF9 that were independent of STAT1. In summary, our large-scale dataset and integrative analysis of JAK-STAT mutant and wild-type mice uncovered a crucial role of JAK-STAT signaling in unstimulated immune cells, where it contributes to a poised epigenetic and transcriptional state and helps prepare these cells for rapid response to immune stimuli.

The oncogenic mechanisms of the Janus kinase-signal transducer and activator of transcription pathway in digestive tract tumors

Digestive tract tumors are heterogeneous and involve the dysregulation of multiple signaling pathways. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway plays a notable role in the oncogenesis of digestive tract tumors. Typically activated by pro-inflammatory cytokines, it regulates important biological processes, such as cell growth, differentiation, apoptosis, immune responses, and inflammation. The aberrant activation of this pathway manifests in different forms, including mutations in JAKs, overexpression of cytokine receptors, and sustained STAT activation, and contributes to promoting the malignant characteristics of cancer cells, including uncontrolled proliferation, resistance to apoptosis, enhanced invasion and metastasis, angiogenesis, acquisition of stem-like properties, and drug resistance. Numerous studies have shown that aberrant activation of the JAK-STAT pathway is closely related to the development and progression of digestive tract tumors, contributing to tumor survival, angiogenesis, changes in the tumor microenvironment, and even immune escape processes. In addition, this signaling pathway also affects the sensitivity of digestive tract tumors to chemotherapy and targeted therapy. Therefore, it is crucial to comprehensively understand the oncogenic mechanisms underlying the JAK-STAT pathway in order to develop effective therapeutic strategies against digestive tract tumors. Currently, several JAK-STAT inhibitors are undergoing clinical and preclinical trials as potential treatments for various human diseases. However, further investigation is required to determine the role of this pathway, as well as the effectiveness and safety of its inhibitors, especially in the context of digestive tract tumors. In this review, we provide an overview of the structure, classic activation, and negative regulation of the JAK-STAT pathway. Furthermore, we discuss the pathogenic mechanisms of JAK-STAT signaling in different digestive tract tumors, with the aim of identifying potential novel therapeutic targets. Video Abstract.

Macrophage polarization in tissue fibrosis

Fibrosis can occur in all major organs with relentless progress, ultimately leading to organ failure and potentially death. Unfortunately, current clinical treatments cannot prevent or reverse tissue fibrosis. Thus, new and effective antifibrotic therapeutics are urgently needed. In recent years, a growing body of research shows that macrophages are involved in fibrosis. Macrophages are highly heterogeneous, polarizing into different phenotypes. Some studies have found that regulating macrophage polarization can inhibit the development of inflammation and cancer. However, the exact mechanism of macrophage polarization in different tissue fibrosis has not been fully elucidated. This review will discuss the major signaling pathways relevant to macrophage-driven fibrosis and profibrotic macrophage polarization, the role of macrophage polarization in fibrosis of lung, kidney, liver, skin, and heart, potential therapeutics targets, and investigational drugs currently in development, and hopefully, provide a useful review for the future treatment of fibrosis.

The ins and outs of innate and adaptive type 2 immunity

Type 2 immunity is orchestrated by a canonical group of cytokines primarily produced by innate lymphoid cells, group 2, and their adaptive counterparts, CD4+ helper type 2 cells, and elaborated by myeloid cells and antibodies that accumulate in response. Here, we review the cytokine and cellular circuits that mediate type 2 immunity. Building from insights in cytokine evolution, we propose that innate type 2 immunity evolved to monitor the status of microbe-rich epithelial barriers (outside) and sterile parenchymal borders (inside) to meet the functional demands of local tissue, and, when necessary, to relay information to the adaptive immune system to reinforce demarcating borders to sustain these efforts. Allergic pathology likely results from deviations in local sustaining units caused by alterations imposed by environmental effects during postnatal developmental windows and exacerbated by mutations that increase vulnerabilities. This framework positions T2 immunity as central to sustaining tissue repair and regeneration and provides a context toward understanding allergic disease.

Cytokine receptor DOME controls wing disc development in Bombyx mori

In multicellular organisms, the JAK/STAT signaling pathway is involved in cell proliferation, differentiation, apoptosis, and immune regulation. Through activation of the Stat92E transcription factor, JAK/STAT signaling induced proper wing development in Drosophila. Domeless (DOME) was the first identified invertebrate JAK/STAT receptor. However, the function of DOME in Bombyx mori development remains unclear, especially in wing morphogenesis. In this study, we isolated the cytokine receptor DOME gene in B. mori and evaluated its function in DOME-knockout models. We found that overexpression of DOME at the cellular level upregulated the expression of JAK/STAT pathway-related genes, promoted proliferation, and inhibited apoptosis. The results of the interference with DOME had the opposite effects with those of overexpression at the cellular level. Using CRISPR/Cas9 technology, we constructed a DOME-knockout transgenic silkworm strain (KO-DOME) and found that the wings of the pupa and moth stages were vesicle-shaped and smaller than those of the wild-type silkworm. Some KO-DOME silkworms were unable to extend their wings from the pupal case after eclosion. We detected the expression of cyclin and apoptosis-related genes in the wing disc of the moth stage and found that some cyclin genes, such as CyclinA, CyclinB, and CyclinD, were downregulated, whereas apoptotic genes, such as Caspase1, Caspase3, and Caspase8, were upregulated. We propose that DOME regulates cell proliferation and apoptosis by affecting the JAK/STAT signaling pathway, ultimately influencing the development of wing discs. Our study provides empirical evidence for the biological function of the silkworm DOME gene, which is essential for the normal development of wings.

Cytokine Receptor Diversity in the Lamprey Predicts the Minimal Essential Cytokine Networks of Vertebrates

The vertebrate adaptive immune systems (Agnatha and Gnathostomata) use sets of T and B lymphocyte lineages that somatically generate highly diverse repertoires of Ag-specific receptors and Abs. In Gnathostomata, cytokine networks regulate the activation of lymphoid and myeloid cells, whereas little is known about these components in Agnathans. Most gnathostome cytokines are four-helix bundle cytokines with poorly conserved primary sequences. In contrast, sequence conservation across bilaterians has been observed for cognate cytokine receptor chains, allowing their structural classification into two classes, and for downstream JAK/STAT signaling mediators. With conserved numbers among Gnathostomata, human cytokine receptor chains (comprising 34 class I and 12 class II) are able to interact with 28 class I helical cytokines (including most ILs) and 16 class II cytokines (including all IFNs), respectively. Hypothesizing that the arsenal of cytokine receptors and transducers may reflect homologous cytokine networks, we analyzed the lamprey genome and transcriptome to identify genes and transcripts for 23 class I and five class II cytokine receptors alongside one JAK signal mediator and four STAT transcription factors. On the basis of deduction of their respective orthologs, we predict that these receptors may interact with 16 class I and 3 class II helical cytokines (including IL-4, IL-6, IL-7, IL-12, IL-10, IFN-γ, and thymic stromal lymphoprotein homologs). On the basis of their respective activities in mammals, this analysis suggests the existence of lamprey cytokine networks that may regulate myeloid and lymphoid cell differentiation, including potential Th1/Th2 polarization. The predicted networks thus appear remarkably homologous to those of Gnathostomata, albeit reduced to essential functions.

Enzymes in the time of COVID-19: An overview about the effects in the human body, enzyme market, and perspectives for new drugs

The rising pandemic caused by a coronavirus, resulted in a scientific quest to discover some effective treatments against its etiologic agent, the severe acute respiratory syndrome‐coronavirus 2 (SARS‐CoV‐2). This research represented a significant scientific landmark and resulted in many medical advances. However, efforts to understand the viral mechanism of action and how the human body machinery is subverted during the infection are still ongoing. Herein, we contributed to this field with this compilation of the roles of both viral and human enzymes in the context of SARS‐CoV‐2 infection. In this sense, this overview reports that proteases are vital for the infection to take place: from SARS‐CoV‐2 perspective, the main protease (M^pro) and papain‐like protease (PL^pro) are highlighted; from the human body, angiotensin‐converting enzyme‐2, transmembrane serine protease‐2, and cathepsins (CatB/L) are pointed out. In addition, the influence of the virus on other enzymes is reported as the JAK/STAT pathway and the levels of lipase, enzymes from the cholesterol metabolism pathway, amylase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and glyceraldehyde 3‐phosphate dehydrogenase are also be disturbed in SARS‐CoV‐2 infection. Finally, this paper discusses the importance of detailed enzymatic studies for future treatments against SARS‐CoV‐2, and how some issues related to the syndrome treatment can create opportunities in the biotechnological market of enzymes and the development of new drugs.

Physiological ROS controls Upd3-dependent modeling of ECM to support cardiac function in Drosophila

Despite their highly reactive nature, reactive oxygen species (ROS) at the physiological level serve as signaling molecules regulating diverse biological processes. While ROS usually act autonomously, they also function as local paracrine signals by diffusing out of the cells producing them. Using in vivo molecular genetic analyses in Drosophila, we provide evidence for ROS-dependent paracrine signaling that does not entail ROS release. We show that elevated levels of physiological ROS within the pericardial cells activate a signaling cascade transduced by Ask1, c-Jun N-terminal kinase, and p38 to regulate the expression of the cytokine Unpaired 3 (Upd3). Upd3 released by the pericardial cells controls fat body-specific expression of the extracellular matrix (ECM) protein Pericardin, essential for cardiac function and healthy life span. Therefore, our work reveals an unexpected inter-organ communication circuitry wherein high physiological levels of ROS regulate cytokine-dependent modulation of cardiac ECM with implications in normal and pathophysiological conditions.

PAHs and PCBs Affect Functionally Intercorrelated Genes in the Sea Urchin Paracentrotus lividus Embryos

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) represent the most common pollutants in the marine sediments. Previous investigations demonstrated short-term sublethal effects of sediments polluted with both contaminants on the sea urchin Paracentrotus lividus after 2 months of exposure in mesocosms. In particular, morphological malformations observed in P. lividus embryos deriving from adults exposed to PAHs and PCBs were explained at molecular levels by de novo transcriptome assembly and real-time qPCR, leading to the identification of several differentially expressed genes involved in key physiological processes. Here, we extensively explored the genes involved in the response of the sea urchin P. lividus to PAHs and PCBs. Firstly, 25 new genes were identified and interactomic analysis revealed that they were functionally connected among them and to several genes previously defined as molecular targets of response to the two pollutants under analysis. The expression levels of these 25 genes were followed by Real Time qPCR, showing that almost all genes analyzed were affected by PAHs and PCBs. These findings represent an important further step in defining the impacts of slight concentrations of such contaminants on sea urchins and, more in general, on marine biota, increasing our knowledge of molecular targets involved in responses to environmental stressors.

Lineage-specific gene evolution of innate immunity in Bombyx mori to adapt to challenge by pathogens, especially entomopathogenic fungi

Bombyx mori is a model species of Lepidoptera, in which 21 gene families and 220 genes have been identified as involved in immunity. However, only 45 B. mori - Drosophila melanogaster - Anopheles gambiae - Apis mellifera - Tribolium castaneum 1:1:1:1:1 orthologous genes were identified. B. mori has unique immune factors not found in D. melanogaster - A. gambiae - A. mellifera - T. castaneum. Pattern recognition receptors, signal transducers and effector genes for antifungal immune responses in B. mori have evolved through expansion and modification of existing genes. This review summarizes the current knowledge of the antifungal immune responses of B. mori and focuses on the lineage-specific gene evolution used by Lepidoptera to adapt to the challenge by pathogens, especially entomopathogenic fungi.

Using the Zebrafish as a Genetic Model to Study Erythropoiesis

Vertebrates generate mature red blood cells (RBCs) via a highly regulated, multistep process called erythropoiesis. Erythropoiesis involves synthesis of heme and hemoglobin, clearance of the nuclei and other organelles, and remodeling of the plasma membrane, and these processes are exquisitely coordinated by specific regulatory factors including transcriptional factors and signaling molecules. Defects in erythropoiesis can lead to blood disorders such as congenital dyserythropoietic anemias, Diamond–Blackfan anemias, sideroblastic anemias, myelodysplastic syndrome, and porphyria. The molecular mechanisms of erythropoiesis are highly conserved between fish and mammals, and the zebrafish (Danio rerio) has provided a powerful genetic model for studying erythropoiesis. Studies in zebrafish have yielded important insights into RBC development and established a number of models for human blood diseases. Here, we focus on latest discoveries of the molecular processes and mechanisms regulating zebrafish erythropoiesis and summarize newly established zebrafish models of human anemias.

MiR-210-5p regulates STAT3 activation by targeting STAT5A in the differentiation of dermal fibroblasts

Elucidating the molecular mechanism of the microRNAs in skin fibrosis is critical for identifying a novel therapeutic strategy for hypertrophic scar (HS). In this study, it was shown that miR-210-5p is induced by TGFβ, and that overexpression of miR-210-5p promoted the differentiation of human dermal fibroblasts (HDFs) into myofibroblasts. STAT5A is required for TGFβ-induced STAT3 activity. Here, we show that miR-210-5p attenuated TGFβ-induced STAT3 signaling pathway by suppressing the expression of STAT5A. Taken together, the present study suggests that TGFβ-induced miR-210-5p reduced STAT5A expression, leading to aberrant activation of STAT3, and facilitate skin fibrosis in HDFs.

Post-Translational Modifications of Retroviral HIV-1 Gag Precursors: An Overview of Their Biological Role

Protein post-translational modifications (PTMs) play key roles in eukaryotes since they finely regulate numerous mechanisms used to diversify the protein functions and to modulate their signaling networks. Besides, these chemical modifications also take part in the viral hijacking of the host, and also contribute to the cellular response to viral infections. All domains of the human immunodeficiency virus type 1 (HIV-1) Gag precursor of 55-kDa (Pr55^Gag), which is the central actor for viral RNA specific recruitment and genome packaging, are post-translationally modified. In this review, we summarize the current knowledge about HIV-1 Pr55^Gag PTMs such as myristoylation, phosphorylation, ubiquitination, sumoylation, methylation, and ISGylation in order to figure out how these modifications affect the precursor functions and viral replication. Indeed, in HIV-1, PTMs regulate the precursor trafficking between cell compartments and its anchoring at the plasma membrane, where viral assembly occurs. Interestingly, PTMs also allow Pr55^Gag to hijack the cell machinery to achieve viral budding as they drive recognition between viral proteins or cellular components such as the ESCRT machinery. Finally, we will describe and compare PTMs of several other retroviral Gag proteins to give a global overview of their role in the retroviral life cycle.

Down-Regulation of Long Non-Coding RNA TINCR Induces Cell Dedifferentiation and Predicts Progression in Oral Squamous Cell Carcinoma

Objectives

Recently long non-coding RNAs (lncRNAs) have emerged as novel gene regulators involved in tumorigenic processes, including oral squamous cell carcinoma (OSCC). Here, we identified a differentiation-related lncRNA, terminal differentiation-induced non-coding RNA (TINCR). However, its biological function and clinicopathological significance in OSCC still remain unclear.

Methods

The lncRNA expression profiles in OSCC tissues and paired adjacent non-tumor tissues (NATs) from 10 patients were detected by lncRNA microarrays. Weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) enrichment were performed to identify the most significant module and module functional annotation, respectively. Potential differentiation-related lncRNAs were screened by differential expression analysis. TINCR was further confirmed in OSCC cell lines and tissues of another patient cohort by using qRT-PCR. The correlation between the TINCR expression level and clinicopathological characteristics was analyzed. The effects of TINCR on cell differentiation, migration and invasion were assessed by knockdown or knock-in in vitro and in vivo.

Results

WGCNA and GO enrichment analysis showed that one co-expression network was significantly enriched for epithelial cell differentiation, among which, TINCR was significantly downregulated. qRT-PCR analyses validated down-regulation of TINCR in tumor tissues compared with paired NATs, and its expression was closely correlated with pathological differentiation and lymph node metastasis in patients with OSCC. Patients with lower TINCR expression levels had worse survival. Cell function experiments showed that TINCR played a crucial role in epithelial differentiation. Both TINCR and epithelial differentiation-associated genes, including IVL and KRT4, were significantly upregulated during OSCC cell calcium-induced differentiation but were reduced when cell dedifferentiation occurred in tumor spheres. Overexpression of TINCR dramatically suppressed cell dedifferentiation, migration and invasion in vitro, while knockdown of TINCR had the opposite effects. Upregulation of TINCR significantly elevated the expression of terminal differentiation genes and repressed tumor growth in vivo. Moreover, TINCR significantly suppressed the activation of JAK2/STAT3 signaling in OSCC cells.

Conclusion

Our study suggests that TINCR functions as a tumor suppressor by inducing cell differentiation through modulating JAK2/STAT3 signaling in OSCC. TINCR may serve as a prognostic biomarker and therapeutic target for OSCC.

Target antifungal peptides of immune signalling pathways in silkworm, Bombyx mori, against Beauveria bassiana

Antifungal innate immunity is an important defence used by insects against entomogenous fungi. However, the downstream target antifungal peptides of different immune signalling pathways are unknown. We found that the Toll, Janus kinase/signal transducer and activator of transcription (Jak/STAT) and Immunodeficiency (IMD) signalling pathways in the silkworm, Bombyx mori, can be activated by Beauveria bassiana. Inhibition of the Toll, IMD and Jak/STAT signalling pathways reduced the antifungal activities of silkworm haemolymph. We verified the target antifungal peptides of different immune signalling pathways. The expression patterns of five anti-fungal peptide genes in silkworm larvae and BmN cells were detected after blocking or over-expressing the immune signalling pathways. The Toll signalling pathways mediated the expression of Bmcecropin A, Bmattacin 1 and Bmgloverin 2; IMD signalling pathways mediated Bmenbocin 1, Bmgloverin 2 and Bmattacin 1; Jak/STAT signalling pathways mediated Bmstorage protein 30K-19G1 (Bmsp 1), Bmattacin 1 and Bmcecropin A. These data indicated that anti-microbial peptide genes in B. mori evolved through expansion and selection of existing genes to adapt to the challenge of invasive microorganisms such as fungi. This information provides insight into the antifungal immune responses in B. mori and aids understanding of insect immune regulation mechanisms.

Signal transducer and activator of transcription is involved in the expression regulation of ecdysteroid-induced insulin-like growth factor-like peptide in the pupal wing disc of silkworm, Bombyx mori

In insects, 20-hydroxyecdysone (20E) and insulin-like growth factor-like peptides (IGFLPs) regulate the development of imaginal discs. However, how IGFLPs are up-regulated to impact the development of the pupal wing disc is still unclear. In this study, we investigated the expression regulation of IGFLP in the pupal wing disc of silkworm, Bombyx mori. We confirmed that B. mori IGFLP (BmIGFLP) was mainly expressed in the pupal wing disc and the expression of BmIGFLP could be significantly induced by 20E. Bioinformatics analysis of BmIGFLP promoter sequence revealed three cis-regulation elements (CREs) of signal transducer and activator of transcription (STAT), which is a key component in the Janus-activated kinase / STAT pathway. Luciferase activity assays showed that two CREs enhanced the transcriptional activity of BmIGFLP. Electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrated that BmSTAT proteins in the nuclear extracts of B. mori pupal wing discs and BmN cells could only bind to the STAT CRE3, indicating that STAT CRE3 activated by BmSTAT enhances BmIGFLP expression at pupal stages. Although 20E could not enhance the expression of BmSTAT, 20E enhanced the nucleus translocation of BmSTAT to bind with the STAT CRE3 in the BmIGFLP promoter. The increase of transcriptional activity of the STAT CRE3 by overexpression of BmSTAT and addition of 20E in BmN cells confirmed this result. Taken together, all data indicate that BmSTAT is one of the transcription factors activating 20E-induced BmIGFLP expression in the pupal wing disc.

Role of the JAK/STAT Pathway in Cervical Cancer: Its Relationship with HPV E6/E7 Oncoproteins

The janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway is associated with the regulation of essential cellular mechanisms, such as proliferation, invasion, survival, inflammation, and immunity. Aberrant JAK/STAT signaling contributes to cancer progression and metastatic development. STAT proteins play an essential role in the development of cervical cancer, and the inhibition of the JAK/STAT pathway may be essential for enhancing tumor cell death. Persistent activation of different STATs is present in a variety of cancers, including cervical cancer, and their overactivation may be associated with a poor prognosis and poor overall survival. The oncoproteins E6 and E7 play a critical role in the progression of cervical cancer and may mediate the activation of the JAK/STAT pathway. Inhibition of STAT proteins appears to show promise for establishing new targets in cancer treatment. The present review summarizes the knowledge about the participation of the different components of the JAK/STAT pathway and the participation of the human papillomavirus (HPV) associated with the process of cellular malignancy.

Larval zebrafish as an in vitro model for evaluating toxicological effects of mycotoxins

The presence of mycotoxins in food has created concern. Mycotoxin prevalence in our environment has changed in the last few years maybe due to climatic and other environmental changes. Evidence has emerged from in vitro and in vivo models: some mycotoxins have been found to be potentially carcinogenic, embryogenically harmful, teratogenic, and to generate nephrotoxicity. The risk assessment of exposures to mycotoxins at early life stages became mandatory. In this regard, the effects of toxic compounds on zebrafish have been widely studied, and more recently, mycotoxins have been tested with respect to their effects on developmental and teratogenic effects in this model system, which offers several advantages as it is an inexpensive and an accessible vertebrate model to study developmental toxicity. External post-fertilization and quick maturation make it sensitive to environmental effects and facilitate the detection of endpoints such as morphological deformities, time of hatching, and behavioral responses. Therefore, there is a potential for larval zebrafish to provide new insights into the toxicological effects of mycotoxins. We provide an overview of recent mycotoxin toxicological research in zebrafish embryos and larvae, highlighting its usefulness to toxicology and discuss the strengths and limitations of this model system.

Transcriptome response comparison between vector and non-vector aphids after feeding on virus-infected wheat plants

BACKGROUND

Plant viruses maintain intricate interactions with their vector and non-vector insects and can impact the fitness of insects. However, the details of their molecular and cellular mechanisms have not been studied well. We compared the transcriptome-level responses in vector and non-vector aphids (Schizaphis graminum and Rhopalosiphum padi, respectively) after feeding on wheat plants with viral infections (Barley Yellow Dwarf Virus (BYDV) and Wheat dwarf virus (WDV), respectively). We conducted differentially expressed gene (DEG) annotation analyses and observed DEGs related to immune pathway, growth, development, and reproduction. And we conducted cloning and bioinformatic analyses of the key DEG involved in immune.

RESULTS

For all differentially expressed gene analyses, the numbers of DEGs related to immune, growth, development, reproduction and cuticle were higher in vector aphids than in non-vector aphids. STAT5B (signal transducer and activator of transcription 5B), which is involved in the JAK-STAT pathway, was upregulated in R. padi exposed to WDV. The cloning and bioinformatic results indicated that the RpSTAT5B sequence contains a 2082 bp ORF encoding 693 amino acids. The protein molecular weight is 79.1 kD and pI is 8.13. Analysis indicated that RpSTAT5B is a non-transmembrane protein and a non-secreted protein. Homology and evolutionary analysis indicated that RpSTAT5B was closely related to R. maidis.

CONCLUSIONS

Unigene expression analysis showed that the total number of differentially expressed genes (DEGs) in the vector aphids was higher than that in the non-vector aphids. Functional enrichment analysis showed that the DEGs related to immunity, growth and reproduction in vector aphids were higher than those in non-vector aphids, and the differentially expressed genes related to immune were up-regulated. This study provides a basis for the evaluation of the response mechanisms of vector/non-vector insects to plant viruses.

Targeting Janus Kinases and Signal Transducer and Activator of Transcription 3 to Treat Inflammation, Fibrosis, and Cancer: Rationale, Progress, and Caution

Before it was molecularly cloned in 1994, acute-phase response factor or signal transducer and activator of transcription (STAT)3 was the focus of intense research into understanding the mammalian response to injury, particularly the acute-phase response. Although known to be essential for liver production of acute-phase reactant proteins, many of which augment innate immune responses, molecular cloning of acute-phase response factor or STAT3 and the research this enabled helped establish the central function of Janus kinase (JAK) family members in cytokine signaling and identified a multitude of cytokines and peptide hormones, beyond interleukin-6 and its family members, that activate JAKs and STAT3, as well as numerous new programs that their activation drives. Many, like the acute-phase response, are adaptive, whereas several are maladaptive and lead to chronic inflammation and adverse consequences, such as cachexia, fibrosis, organ dysfunction, and cancer. Molecular cloning of STAT3 also enabled the identification of other noncanonical roles for STAT3 in normal physiology, including its contribution to the function of the electron transport chain and oxidative phosphorylation, its basal and stress-related adaptive functions in mitochondria, its function as a scaffold in inflammation-enhanced platelet activation, and its contributions to endothelial permeability and calcium efflux from endoplasmic reticulum. In this review, we will summarize the molecular and cellular biology of JAK/STAT3 signaling and its functions under basal and stress conditions, which are adaptive, and then review maladaptive JAK/STAT3 signaling in animals and humans that lead to disease, as well as recent attempts to modulate them to treat these diseases. In addition, we will discuss how consideration of the noncanonical and stress-related functions of STAT3 cannot be ignored in efforts to target the canonical functions of STAT3, if the goal is to develop drugs that are not only effective but safe. SIGNIFICANCE STATEMENT: Key biological functions of Janus kinase (JAK)/signal transducer and activator of transcription (STAT)3 signaling can be delineated into two broad categories: those essential for normal cell and organ development and those activated in response to stress that are adaptive. Persistent or dysregulated JAK/STAT3 signaling, however, is maladaptive and contributes to many diseases, including diseases characterized by chronic inflammation and fibrosis, and cancer. A comprehensive understanding of JAK/STAT3 signaling in normal development, and in adaptive and maladaptive responses to stress, is essential for the continued development of safe and effective therapies that target this signaling pathway.

Genipin induces mitochondrial dysfunction and apoptosis via downregulation of Stat3/mcl-1 pathway in gastric cancer

BACKGROUND

Genipin is a compound derived from gardenia fruit extract. Although Genipin has anti-tumor effects in various cancers, its effect and mechanism in gastric cancer remain unclear. Here, we investigated the relationship between the anticancer effect of Genipin and signal transducer and activator of transcription (Stat3)/myeloid cell leukemia-1 (Mcl-1) in human gastric cancers.

METHODS

MTT assays were performed to determine the cell viability of gastric cancer and gastric epithelial cell lines (AGS, MKN45, SNU638, MKN74, HFE-145). A TUNEL assay and Western blotting were carried out to investigate apoptosis. Stat3 activity was measured by proteome profiler phospho kinase array, immunofluorescence and immunoblotting. Mitochondria function was monitored with an XF24 analyzer and by flow cytometry, confocal microscopy using fluorescent probes for general mitochondrial membrane potential (MMP).

RESULTS

Genipin induced apoptosis in gastric cancer cells, including AGS and MKN45 cells. Genipin also reduced Mcl-1 mRNA and protein levels. Furthermore, we found that phosphorylation of Stat3 is regulated by Genipin. Additionally, the protein level of phospho Janus kinase 2 (JAK2) was decreased by Genipin treatment, indicating that the Stat3/JAK2/Mcl-1 pathway is suppressed by Genipin treatment in gastric cancer cells. Mcl-1 is closely related to mitochondrial function. These findings suggest that Genipin contributes to the collapse of mitochondrial functions like MMP.

CONCLUSIONS

Genipin induced apoptosis by suppressing the Stat3/Mcl-1 pathway and led to mitochondrial dysfunction. Our results reveal a novel mechanism for the anti-cancer effect of Genipin in gastric cancer.

WSV181 inhibits JAK/STAT signaling and promotes viral replication in Drosophila

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway plays a critical role in host defense against viral infections. Here, we report the use of the Drosophila model system to investigate the modulation of the JAK/STAT pathway by the white spot syndrome virus (WSSV) protein WSV181. WSV181 overexpression in transgenic flies resulted in the downregulation of STAT92E and STAT92E-targeted genes. This result indicates that WSV181 can suppress JAK/STAT signaling by controlling STAT92E expression. An infection experiment was carried out on transgenic Drosophila infected with Drosophila C virus and on Litopenaeus vannamei injected with recombinant WSV181 and WSSV. The increased viral load and suppressed transcript levels of JAK/STAT pathway components indicate that WSV181 can promote viral proliferation by inhibiting the JAK/STAT pathway. This study provided evidence for the role of WSV181 in viral replication and revealed a new mechanism through which WSSV evades host immunity to maintain persistent infection.

Contribution of Wound-Associated Cells and Mediators in Orchestrating Gastrointestinal Mucosal Wound Repair

The gastrointestinal mucosa, structurally formed by the epithelium and lamina propria, serves as a selective barrier that separates luminal contents from the underlying tissues. Gastrointestinal mucosal wound repair is orchestrated by a series of spatial and temporal events that involve the epithelium, recruited immune cells, resident stromal cells, and the microbiota present in the wound bed. Upon injury, repair of the gastrointestinal barrier is mediated by collective migration, proliferation, and subsequent differentiation of epithelial cells. Epithelial repair is intimately regulated by a number of wound-associated cells that include immune cells and stromal cells in addition to mediators released by luminal microbiota. The highly regulated interaction of these cell types is perturbed in chronic inflammatory diseases that are associated with impaired wound healing. An improved understanding of prorepair mechanisms in the gastrointestinal mucosa will aid in the development of novel therapeutics that promote mucosal healing and reestablish the critical epithelial barrier function.

A Gene Expression Screen in Drosophila melanogaster Identifies Novel JAK/STAT and EGFR Targets During Oogenesis

The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) and epidermal growth factor receptor (EGFR) signaling pathways are conserved regulators of tissue patterning, morphogenesis, and other cell biological processes. During Drosophila oogenesis, these pathways determine the fates of epithelial follicle cells (FCs). JAK/STAT and EGFR together specify a population of cells called the posterior follicle cells (PFCs), which signal to the oocyte to establish the embryonic axes. In this study, whole genome expression analysis was performed to identify genes activated by JAK/STAT and/or EGFR. We observed that 317 genes were transcriptionally upregulated in egg chambers with ectopic JAK/STAT and EGFR activity in the FCs. The list was enriched for genes encoding extracellular matrix (ECM) components and ECM-associated proteins. We tested 69 candidates for a role in axis establishment using RNAi knockdown in the FCs. We report that the signaling protein Semaphorin 1b becomes enriched in the PFCs in response to JAK/STAT and EGFR. We also identified ADAM metallopeptidase with thrombospondin type 1 motif A (AdamTS-A) as a novel target of JAK/STAT in the FCs that regulates egg chamber shape. AdamTS-A mRNA becomes enriched at the anterior and posterior poles of the egg chamber at stages 6 to 7 and is regulated by JAK/STAT. Altering AdamTS-A expression in the poles or middle of the egg chamber produces rounder egg chambers. We propose that AdamTS-A regulates egg shape by remodeling the basement membrane.

The CPLANE protein Intu protects kidneys from ischemia-reperfusion injury by targeting STAT1 for degradation

Intu is known as a ciliogenesis and planar polarity effector (CPLANE) protein. Although roles for Intu have been reported during embryonic development and in the context of developmental disorders, its function and regulation in adult tissues remain poorly understood. Here we show that ablation of Intu specifically in kidney proximal tubules aggravates renal ischemia-reperfusion injury, and leads to defective post-injury ciliogenesis. We identify signal transducer and activator of transcription 1 (STAT1) as a novel interacting partner of Intu. In vitro, Intu and STAT1 colocalize at the centriole/basal body area, and Intu promotes proteasomal degradation of STAT1. During cell stress, Intu expression preserves cilia length and cell viability, and these actions are antagonized by STAT1 expression. Thus, we propose a role for Intu in protecting cells and tissues after injury by targeting STAT1 for degradation and maintaining primary cilia.

A switch in transcription and cell fate governs the onset of an epigenetically-deregulated tumor in Drosophila

Tumor initiation is often linked to a loss of cellular identity. Transcriptional programs determining cellular identity are preserved by epigenetically-acting chromatin factors. Although such regulators are among the most frequently mutated genes in cancer, it is not well understood how an abnormal epigenetic condition contributes to tumor onset. In this work, we investigated the gene signature of tumors caused by disruption of the Drosophila epigenetic regulator, polyhomeotic (ph). In larval tissue ph mutant cells show a shift towards an embryonic-like signature. Using loss- and gain-of-function experiments we uncovered the embryonic transcription factor knirps (kni) as a new oncogene. The oncogenic potential of kni lies in its ability to activate JAK/STAT signaling and block differentiation. Conversely, tumor growth in ph mutant cells can be substantially reduced by overexpressing a differentiation factor. This demonstrates that epigenetically derailed tumor conditions can be reversed when targeting key players in the transcriptional network.

When an animal is developing as an embryo, different cells start to specialize into the specific cell types needed to form the tissues and organs of the body. How an individual cell commits to become a certain type of cell is mostly determined by which of the genes in its DNA are active. In animal cells, DNA is wrapped around proteins called histones, and one way that cells can maintain their distinct pattern of gene activity is via chemical tags on the histones. These tags can switch nearby genes on or off, and are added or removed by other proteins called epigenetic regulators. The epigenetic tags are also stably inherited when the cell divides, meaning that a cell’s identity can be maintained over many cell generations.

If epigenetic regulators fail to work properly or get disrupted, the pattern of gene activity in a cell becomes altered. As a consequence, that cell can lose its identity and will often turn into a cancer cell. In fact, mutations in epigenetic regulators are found in several human cancers. It is not yet understood how these changes in gene expression lead cells to become cancerous.

Torres et al. have now analyzed an epigenetic regulator called Polyhomeotic in developing larvae of the fruit fly, Drosophila melanogaster. The results show that when Polyhomeotic is not produced the fly larvae develop tumors. Moreover, the mutant cells without Polyhomeotic had different gene expression profiles compared to normal cells. This in turn caused the mutant cells, which had previously committed to a certain fate, to become more like the unspecialized cells found in early embryos.

Torres et al. next showed that, among the genes that were incorrectly regulated when Polyhomeotic’s activity was compromised, one gene called knirps was switched on by mistake, which led the mutant cells to become tumor cells. When the activity of knirps was reduced instead, almost no tumors grew. Additionally, Torres et al. found that the protein encoded by knirps activates a signaling pathway that keeps tumor cells unspecialized by blocking their normal progress to a more mature and specialized state – a process known as differentiation. Experimentally raising the levels of a different molecule that ultimately promotes differentiation caused the tumor cells to grow less.

These findings suggest that tumors caused when epigenetic regulation goes awry may be reversed by targeting key genes such as knirps. Further work is now needed to test whether these findings will also extend to humans. Forcing cancer cells from a highly dividing, non-specialized state into a dead-end, mature state may lead to new ways to treat cancer.

Crosstalk between CCL7 and CCR3 promotes metastasis of colon cancer cells via ERK-JNK signaling pathways

Chemokine ligand 7 (CCL7) enhances cancer progression and metastasis via epithelial-mesenchymal transition (EMT). However, little is known about the molecular mechanism of CCL7-induced EMT signaling cascade in colon cancer. Thus, the objective of this study was to investigate CCL7-induced EMT signaling pathway and its role in the progression and metastasis of colon cancer. To demonstrate the effect of CCL7 on EMT induction, HCT116 and HT29 cells overexpressing CCL7 were generated. CCL7-induced EMT and its downstream signaling pathway were evaluated by both in vitro and in vivo experiments. In in vitro studies, CCL7 was found to interplay with CC chemokine receptor 3 (CCR3), resulting in enhanced cellular proliferation, invasion, and migration via ERK and JNK signaling pathway. To validate these findings, we established ectopic and orthotopic mouse models injected with CCL7-overexpressed cells. In ectopic mouse models, we observed that CCL7-overexpressed cells grew significantly faster than control cells. In orthotopic mouse models, we found that liver and lung metastasis developed only in mice injected with CCL7-overexpressed cells. This study is the first one focusing on the EMT cascade via CCL7-CCR3-ERK-JNK signaling axis in colon cancer. Our novel findings will improve our understanding on the mechanism of metastatic process and provide potential therapeutic strategies for preventing metastasis in colon cancer.

JAK/STAT and TGF-ß activation as potential adverse outcome pathway of TiO2NPs phototoxicity in Caenorhabditis elegans

Titanium dioxide nanoparticles (TiO₂NPs) are widely used nanoparticles, whose catalytic activity is mainly due to photoactivation. In this study, the toxicity of TiO₂NPs was investigated on the nematode Caenorhabditis elegans, with and without UV activation. Comparative analyses across the four treatments revealed that UV-activated TiO₂NPs led to significant reproductive toxicity through oxidative stress. To understand the underlying molecular mechanism, transcriptomics and metabolomics analyses were conducted, followed by whole-genome network-based pathway analyses. Differential expression analysis from microarray data revealed only 4 DEGs by exposure to TiO₂NPs alone, compared to 3,625 and 3,286 DEGs by UV alone and UV-activated TiO₂NPs, respectively. Pathway analyses suggested the possible involvement of the JAK/STAT and TGF-ß pathways in the phototoxicity of TiO₂NPs, which correlated with the observation of increased gene expression of those pathways. Comparative analysis of C. elegans response across UV activation and TiO₂NPs exposure was performed using loss-of-function mutants of genes in these pathways. Results indicated that the JAK/STAT pathway was specific to TiO₂NPs, whereas the TGF-ß pathway was specific to UV. Interestingly, crosstalk between these pathways was confirmed by further mutant analysis. We consider that these findings will contribute to understand the molecular mechanisms of toxicity of TiO₂NPs in the natural environment.

JAK-STAT signaling regulation of chicken embryonic stem cell differentiation into male germ cells

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is crucial in chicken germ stem cell differentiation, but its role in the regulation of germ cell differentiation is unknown. To address this, cucurbitacin I or interleukin 6 was used to inhibit or activate JAK-STAT signaling during embryonic stem cells (ESCs) differentiation. The expression of downstream JAK-STAT signaling molecules was assessed by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). PAS, and immunohistochemical staining of frozen sections was used to determine the appearance of primordial germ cells (PGCs) and, later, spermatogonial stem cells (SSCs) during gonadal development. Inhibition of the JAK-STAT signaling resulted in decreased expression of JAK2 and STAT3 as well as of PGCs markers; moreover, the proportion of CVH and C-KIT positive cells as well as the yield of PGCs were remarkably decreased, and the gonad was smaller than that of control samples. Conversely, activation of JAK-STAT resulted in increased expression of JAK2 and STAT3 as well as that of PGC marker CVH. In addition, the proportion of CVH and C-KIT-positive cells as well as the PGC yield was increased, and the gonad was significantly larger than that from control samples. Collectively, our results suggested that JAK-STAT effectively promoted the formation of PGCs in the genital ridge during early embryogenesis in vivo and played a positive role in the regulation of ESC to SSC differentiation in vitro, with JAK2 and STAT3 functioning as pivotal factors for intracellular signal transduction.

Spatiotemporal regulation of cell fusion by JNK and JAK/STAT signaling during Drosophila wound healing

Cell-cell fusion is widely observed during development and disease, and imposes a dramatic change on participating cells. Cell fusion should be tightly controlled, but the underlying mechanism is poorly understood. Here, we found that the JAK/STAT pathway suppressed cell fusion during wound healing in the Drosophila larval epidermis, restricting cell fusion to the vicinity of the wound. In the absence of JAK/STAT signaling, a large syncytium containing a 3-fold higher number of nuclei than observed in wild-type tissue formed in wounded epidermis. The JAK/STAT ligand-encoding genes upd2 and upd3 were transcriptionally induced by wounding, and were required for suppressing excess cell fusion. JNK (also known as Basket in flies) was activated in the wound vicinity and activity peaked at ∼8 h after injury, whereas JAK/STAT signaling was activated in an adjoining concentric ring and activity peaked at a later stage. Cell fusion occurred primarily in the wound vicinity, where JAK/STAT activation was suppressed by fusion-inducing JNK signaling. JAK/STAT signaling was both necessary and sufficient for the induction of βPS integrin (also known as Myospheroid) expression, suggesting that the suppression of cell fusion was mediated at least in part by integrin protein.

Damage-Induced Cell Regeneration in the Midgut of Aedes albopictus Mosquitoes

Mosquito-transmitted diseases cause over one million deaths every year. A better characterization of the vector’s physiology and immunity should provide valuable knowledge for the elaboration of control strategies. Mosquitoes depend on their innate immunity to defend themselves against pathogens. These pathogens are acquired mainly through the oral route, which places the insects’ gut at the front line of the battle. Indeed, the epithelium of the mosquito gut plays important roles against invading pathogens acting as a physical barrier, activating local defenses and triggering the systemic immune response. Therefore, the gut is constantly confronted to stress and often suffers cellular damage. In this study, we show that dividing cells exist in the digestive tract of adult A. albopictus and that these cells proliferate in the midgut after bacterial or chemical damage. An increased transcription of signaling molecules that regulate the EGFR and JAK/STAT pathways was also observed, suggesting a possible involvement of these pathways in the regeneration of damaged guts. This work provides evidence for the presence of regenerative cells in the mosquito guts, and paves the way towards a molecular and cellular characterization of the processes required to maintain mosquito’s midgut homeostasis in both normal and infectious conditions.

Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development

Vertebrate sexual fate is decided primarily by the individual's genotype (GSD), by the environmental temperature during development (TSD), or both. Turtles exhibit TSD and GSD, making them ideal to study the evolution of sex determination. Here we analyze temperature-specific gonadal transcriptomes (RNA-sequencing validated by qPCR) of painted turtles (Chrysemys picta TSD) before and during the thermosensitive period, and at equivalent stages in soft-shell turtles (Apalone spinifera-GSD), to test whether TSD's and GSD's transcriptional circuitry is identical but deployed differently between mechanisms. Our data show that most elements of the mammalian urogenital network are active during turtle gonadogenesis, but their transcription is generally more thermoresponsive in TSD than GSD, and concordant with their sex-specific function in mammals [e.g., upregulation of Amh, Ar, Esr1, Fog2, Gata4, Igf1r, Insr, and Lhx9 at male-producing temperature, and of β-catenin, Foxl2, Aromatase (Cyp19a1), Fst, Nf-kb, Crabp2 at female-producing temperature in Chrysemys]. Notably, antagonistic elements in gonadogenesis (e.g., β-catenin and Insr) were thermosensitive only in TSD early-embryos. Cirbp showed warm-temperature upregulation in both turtles disputing its purported key TSD role. Genes that may convert thermal inputs into sex-specific development (e.g., signaling and hormonal pathways, RNA-binding and heat-shock) were differentially regulated. Jak-Stat, Nf-κB, retinoic-acid, Wnt, and Mapk-signaling (not Akt and Ras-signaling) potentially mediate TSD thermosensitivity. Numerous species-specific ncRNAs (including Xist) were differentially-expressed, mostly upregulated at colder temperatures, as were unannotated loci that constitute novel TSD candidates. Cirbp showed warm-temperature upregulation in both turtles. Consistent transcription between turtles and alligator revealed putatively-critical reptilian TSD elements for male (Sf1, Amh, Amhr2) and female (Crabp2 and Hspb1) gonadogenesis. In conclusion, while preliminary, our data helps illuminate the regulation and evolution of vertebrate sex determination, and contribute genomic resources to guide further research into this fundamental biological process.

A CgIFNLP receptor from Crassostrea gigas and its activation of the related genes in human JAK/STAT signaling pathway

Interferon is a highly pleiotropic cytokine, once binding to its receptors, can activate JAK kinases and STAT transcription factors to initiate the transcription of genes downstream from interferon-stimulated response elements. In the present study, a cytokine receptor-like 3 molecule was selected and cloned from oyster Crassostrea gigas, which contained a fibronectin type III domain (designed CgIFNR-3). The expression pattern of CgIFNR-3 mRNA was detected in all the tested tissues including mantle, gills, hepatopancreas, muscle, and hemocytes, with the highest expression level in hemocytes. After poly (I: C) stimulation, the expression level of CgIFNR-3 in hemocytes was observed to significantly increase at 3 h (13.06-fold, p < 0.01). CgIFNR-3 was indicated to interact with CgIFNLP by in vitro GST pull-down assay, and to activate the expression of transcription factors including ISRE, STAT3 and GAS, in human Janus kinase signal transducer and activator of transcription (JAK/STAT) pathway after co-transfection in HEK-293T cells in the reporter luciferase activity assay. These results suggested that CgIFNR-3 could bind to CgIFNLP as an interferon receptor and participate in the activation of JAK/STAT pathway in human, which will benefit for intensive studies of interferon signaling pathway in mollusc.

Annotation of the Asian Citrus Psyllid Genome Reveals a Reduced Innate Immune System

Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as Huanglongbing. The citrus greening bacteria, Candidatus Liberibacter asiaticus (CLas), is a persistent propagative pathogen transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). Hemipterans characterized to date lack a number of insect immune genes, including those associated with the Imd pathway targeting Gram-negative bacteria. The D. citri draft genome was used to characterize the immune defense genes present in D. citri. Predicted mRNAs identified by screening the published D. citri annotated draft genome were manually searched using a custom database of immune genes from previously annotated insect genomes. Toll and JAK/STAT pathways, general defense genes Dual oxidase, Nitric oxide synthase, prophenoloxidase, and cellular immune defense genes were present in D. citri. In contrast, D. citri lacked genes for the Imd pathway, most antimicrobial peptides, 1,3-β-glucan recognition proteins (GNBPs), and complete peptidoglycan recognition proteins. These data suggest that D. citri has a reduced immune capability similar to that observed in A. pisum, P. humanus, and R. prolixus. The absence of immune system genes from the D. citri genome may facilitate CLas infections, and is possibly compensated for by their relationship with their microbial endosymbionts.

Identification of Novel Regulators of the JAK/STAT Signaling Pathway that Control Border Cell Migration in the Drosophila Ovary

The Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signaling pathway is an essential regulator of cell migration both in mammals and fruit flies. Cell migration is required for normal embryonic development and immune response but can also lead to detrimental outcomes, such as tumor metastasis. A cluster of cells termed “border cells” in the Drosophila ovary provides an excellent example of a collective cell migration, in which two different cell types coordinate their movements. Border cells arise within the follicular epithelium and are required to invade the neighboring cells and migrate to the oocyte to contribute to a fertilizable egg. Multiple components of the STAT signaling pathway are required during border cell specification and migration; however, the functions and identities of other potential regulators of the pathway during these processes are not yet known. To find new components of the pathway that govern cell invasiveness, we knocked down 48 predicted STAT modulators using RNAi expression in follicle cells, and assayed defective cell movement. We have shown that seven of these regulators are involved in either border cell specification or migration. Examination of the epistatic relationship between candidate genes and Stat92E reveals that the products of two genes, Protein tyrosine phosphatase 61F (Ptp61F) and brahma (brm), interact with Stat92E during both border cell specification and migration.

The Function of Fish Cytokines

What is known about the biological activity of fish cytokines is reviewed. Most of the functional studies performed to date have been in teleost fish, and have focused on the induced effects of cytokine recombinant proteins, or have used loss- and gain-of-function experiments in zebrafish. Such studies begin to tell us about the role of these molecules in the regulation of fish immune responses and whether they are similar or divergent to the well-characterised functions of mammalian cytokines. This knowledge will aid our ability to determine and modulate the pathways leading to protective immunity, to improve fish health in aquaculture.

Looking Beyond the Genes: The Interplay Between Signaling Pathways and Mechanics in the Shaping and Diversification of Epithelial Tissues

The core of Evo-Devo lies in the intuition that the way tissues grow during embryonic development, the way they sustain their structure and function throughout lifetime, and the way they evolve are closely linked. Epithelial tissues are ubiquitous in metazoans, covering the gut and internal branched organs, as well as the skin and its derivatives (ie, teeth). Here, we discuss in vitro, in vivo, and in silico studies on epithelial tissues to illustrate the conserved, dynamical, and complex aspects of their development. We then explore the implications of the dynamical and nonlinear nature of development on the evolution of their size and shape at the phenotypic and genetic levels. In rare cases, when the interplay between signaling and mechanics is well understood at the cell level, it is becoming clear that the structure of development leads to covariation of characters, an integration which in turn provides some predictable structure to evolutionary changes. We suggest that such nonlinear systems are prone to genetic drift, cryptic genetic variation, and context-dependent mutational effects. We argue that experimental and theoretical studies at the cell level are critical to our understanding of the phenotypic and genetic evolution of epithelial tissues, including carcinomas.

Important roles played by TGF-β member of Bmdpp and Bmdaw in BmNPV infection

Transforming growth factor (TGF)-β superfamily members inhibit Bombyx mori nucleohedrovirus (BmNPV) multiplication in silkworm are not determined. In this study, we first found that BmNPV RNA transcription and protein expression level were regulated by TGF-β members, Decapentaplegic (Bmdpp) and Dawdle (Bmdaw) in the domesticated silkworm, B. mori and silkworm ovary-derived cells. Furthermore, subcellular localization showed that Bmdpp and Bmdaw were mainly presented in cytomembrane of the cultured BmN cells. Tissues expression pattern analysis found that the highest expression levels of Bmdpp and Bmdaw genes were in the hemocyte of fifth instar larvae. During the immune response, the expression level of Bmdpp gene was elevated and Bmdaw gene was declined in BmNPV infected BmN cells and silkworm. The multiplication of BmNPV was inhibited by overexpression of Bmdpp and Bmdaw genes in BmN cells. RNA interference experiments found that the multiplication of BmNPV was raised with specific siRNAs of Bmdpp and Bmdaw genes in BmN cells. The antiviral immune pathways were not significantly regulated by the TGF-β superfamily members. Taken together, these findings provided a clue to understand the function of Bmdpp and Bmdaw gene in response to the BmNPV infection in silkworm.

Mycotoxin ochratoxin A disrupts renal development via a miR-731/prolactin receptor axis in zebrafish

Mycotoxin ochratoxin A (OTA) frequently contaminates various food and feed products, including cereals, coffee and wine. While the nephrotoxicity and teratogenicity of OTA have been extensively documented, the molecular mechanisms associated with OTA toxicity remained poorly understood in a developing organism. We showed that zebrafish embryos exposed to OTA demonstrated incorrect heart looping and small heart chambers. OTA also impaired the renal morphology and reduced the glomerular filtration rate of the embryonic zebrafish. The treatment of embryos with OTA attenuated the expression of the prolactin receptor, a gene (PRLRa) that has a key role in organogenesis and osmoregulation in vertebrates. OTA not only inhibited the phosphorylation of STAT5 and AKT, but also down-regulated the level of serpina1 mRNA in a dose-dependent manner. On the other hand, the microRNA profiling based on RNA sequencing revealed the up-regulation of microRNA-731 (miR-731) in the OTA-treated embryos. Further in silico analysis predicted that PRLRa was a target gene of miR-731. AntagomiR-731 restored PRLRa levels that had been reduced by OTA and also recovered the pronephros morphology that was damaged by OTA. These observations suggest that the exposure to OTA adversely affected the organogenesis of zebrafish, and the modulation of miR-731 and the PRLR signaling cascade contributed to the abnormal renal development mediated by OTA.

Organ-specific transcriptome response of the small brown planthopper toward rice stripe virus

Rice stripe virus (RSV) causes rice stripe disease and is transmitted by the small brown planthopper (Laodelphax striatellus, SBPH) in a persistent, circulative, and propagative manner. The alimentary canal and salivary gland of SBPH play important roles in viral replication and transmission. However, little is known about the underlying molecular functions of these two organs in the interaction between RSV and SBPH. In this study, organ-specific transcriptomes of the alimentary canal and salivary gland were analyzed in viruliferous and naïve SBPH. The number of differentially expressed unigenes in the alimentary canal was considerably greater than that in the salivary gland after RSV infection, and only 23 unigenes were co-regulated in the two organs. In the alimentary canal, genes involved in lysosome, digestion and detoxification were activated upon RSV infection, whereas the genes related to DNA replication and repair were suppressed. RSV activated RNA transport and repressed the MAPK, mTOR, Wnt, and TGF-beta signaling pathways in the salivary gland. The overall immune reaction toward RSV was much stronger in the salivary gland than in the alimentary canal. RSV activated the pattern recognition molecules and Toll pathway in the salivary gland but inhibited these two reactions in the alimentary canal. The responses from reactive oxygen and the immune-responsive effectors were stronger in the salivary gland than in the alimentary canal after RSV infection. These findings provide clues on the roles of the two organs in confronting RSV infection and aid in the understanding of the interaction between RSV and SBPHs.

Signaling via the CytoR/JAK/STAT/SOCS pathway: Emergence during evolution

Cell-cell signaling represents an essential hallmark of multicellular organisms, which necessarily require a means of communicating between different cell populations, particularly immune cells. Cytokine receptor signaling through the Janus kinase/Signal Transducer and Activator of Transcription/Suppressor of Cytokine Signaling (CytoR/JAK/STAT/SOCS) pathway embodies one important paradigm by which this is achieved. This pathway has been extensively studied in vertebrates and protostomes and shown to play fundamental roles in development and function of immune and other cells. However, our understanding of the origins of the individual pathway components and their assembly into a functional pathway has remained limited. This study examined the origins of each component of this pathway through bioinformatics analysis of key extant species. This has revealed step-wise accretion of individual components over a large evolutionary time-frame, but only in bilateria did a series of innovations allow their final coalescence to form a complete pathway. Assembly of the CytoR/JAK/STAT pathway has followed the retrograde model of pathway evolution, whereas addition of the SOCS component has adhered to the patchwork model.

Identification, gene expression and immune function of the novel Bm-STAT gene in virus-infected Bombyx mori

Genes in the signal transducer and activator of transcription (STAT) family are vital for activities including gene expression and immune response. To investigate the functions of the silkworm Bombyx mori STAT (Bm-STAT) gene in antiviral immunity, two Bm-STAT gene isoforms, Bm-STAT-L for long form and Bm-STAT-S for short form, were cloned. Sequencing showed that the open reading frames were 2313 bp encoding 770 amino acid residues for Bm-STAT-L and 2202 bp encoding 734 amino acid residues for Bm-STAT-S. The C-terminal 42 amino acid residues of Bm-STAT-L were different from the last 7 amino acid residues of Bm-STAT-S. Immunofluorescence showed that Bm-STAT was primarily distributed in the nucleus. Transcription levels of Bm-STAT in different tissues were determined by quantitative PCR, and the results revealed Bm-STAT was mainly expressed in testes. Western blots showed two bands with molecular weights of 70 kDa and 130 kDa in testes, but no bands were detected in ovaries by using anti-Bm-STAT antibody as the primary antibody. Expression of Bm-STAT in hemolymph at 48 h post infection with B. mori macula-like virus (BmMLV) was slightly enhanced compared with controls, suggesting a weak response induced by infection with BmMLV. Hemocyte immunofluorescence showed that Bm-STAT expression was elevated in B. mori nucleopolyhedrovirus (BmNPV)-infected cells. Moreover, resistance of BmN cells to BmNPV was reduced by downregulation of Bm-STAT expression and increased by upregulation. Resistance of BmN cells to BmCPV was not significantly improved by upregulating Bm-STAT expression. Therefore, we concluded that Bm-STAT is a newly identified insect gene of the STAT family. The JAK-STAT pathway has a more specialized role in antiviral defense in silkworms, but JAK-STAT pathway is not triggered in response to all viruses.

Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity

Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid) maintains germline stem cell (GSC) mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities.

Summary: This study provides new insights into the biological functions of a histone demethylase and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities.

STAT3-mediated MMP-2 expression is required for 15-HETE-induced vascular adventitial fibroblast migration

OBJECTIVE

Vascular adventitial fibroblasts (VAFs) migration was involved in neointima formation, and increased 15-HETE levels contributed to vascular remodeling. However, how 15-HETE-induced VAF migration was not clear.

METHODS AND RESULTS

15-HETE-stimulated VAF phenotypic changes and migration as measured by the wound healing assay required STAT3 phosphorylation. JNK1 and CREB inhibition blocked 15-HETE-induced STAT3 activation and VAF changes. 15-HETE-induced MMP-2 expression and secretion were analyzed by Western blot and ELISA, respectively. MMP-2 knockdown blocked VAF migration and phenotypic alterations. JNK1, STAT3 and CREB blockade suppressed 15-HETE-induced MMP-2 expression in VAFs. MMP-2 promoter activity was assessed by chromatin immunoprecipitation using anti-STAT3 antibodies, which demonstrated that STAT3 was essential for 15-HETE-induced MMP-2 expression. Rats that suffered from hypoxia injury with or without treatment were examined. Pulmonary artery remodeling was obviously observed, and even the media was broken. MMP-2-positive staining was observed in the adventitia and intima. MMP-2 Serum secretion was enhanced as detected by ELISA, and MMP-2 and α-SMA protein expressions were increased after inducing hypoxia in the rats, which was restored in rats that had been administrated with NDGA.

CONCLUSION

These results reveal that STAT3-mediated MMP-2 expression is required for 15-HETE induced-VAF migration.