Function of bidirectional sensitivity in the otolith organs established by transcription factor Emx2.

Otolith organs of the inner ear are innervated by two parallel afferent projections to the brainstem and cerebellum. These innervations were proposed to segregate across the line of polarity reversal (LPR) within each otolith organ, which divides the organ into two regions of hair cells (HC) with opposite stereociliary orientation. The relationship and functional significance of these anatomical features are not known. Here, we show regional expression of Emx2 in otolith organs, which establishes LPR, mediates the neuronal segregation across LPR and constitutes the bidirectional sensitivity function. Conditional knockout (cKO) of Emx2 in HCs lacks LPR. Tmie cKO, in which mechanotransduction was abolished selectively in HCs within the Emx2 expression domain also lacks bidirectional sensitivity. Analyses of both mutants indicate that LPR is specifically required for mice to swim comfortably and to traverse a balance beam efficiently, but LPR is not required for mice to stay on a rotating rod.

Crosstalk between angiogenesis and immune regulation in the tumor microenvironment.

Cancer creates a complex tumor microenvironment (TME) composed of immune cells, stromal cells, blood vessels, and various other cellular and extracellular elements. It is essential for the development of anti-cancer combination therapies to understand and overcome this high heterogeneity and complexity as well as the dynamic interactions between them within the TME. Recent treatment strategies incorporating immune-checkpoint inhibitors and anti-angiogenic agents have brought many changes and advances in clinical cancer treatment. However, there are still challenges for immune suppressive tumors, which are characterized by a lack of T cell infiltration and treatment resistance. In this review, we will investigate the crosstalk between immunity and angiogenesis in the TME. In addition, we will look at strategies designed to enhance anti-cancer immunity, to convert "immune suppressive tumors" into "immune activating tumors," and the mechanisms by which these strategies enhance effector immune cell infiltration.

Knockdown of Maged1 inhibits cell cycle progression and causes cell death in mouse embryonic stem cells.

Mouse embryonic stem cells (mESCs) are characterized by self-renewal and pluripotency and can undergo differentiation into the three germ layers (ectoderm, mesoderm, and endoderm). Melanoma-associated antigen D1 (Maged1), which is expressed in all developing and adult tissues, modulates tissue regeneration and development. In the present study, we examined the expression and function of Maged1 in mESCs. Maged1 protein and mRNA expression increased during mESC differentiation. The pluripotency of mESCs was significantly reduced through extracellular signal-regulated kinase 1/2 phosphorylation upon knockdown of Maged1, and through G1 cell cycle arrest during cell division, resulting in significantly reduced mESC proliferation. Moreover, the diameter of the embryoid bodies was significantly reduced, accompanied by increased levels of ectodermal differentiation markers and decreased levels of mesodermal and endodermal differentiation markers. Maged1-knockdown mESC lines showed significantly reduced teratoma volumes and inhibition of teratoma formation in nude mice. Additionally, we observed increased ectodermal markers but decreased mesodermal and endodermal markers in teratoma tissues. These findings show that Maged1 affects mESC pluripotency, proliferation, cell cycle, and differentiation, thereby contributing to our understanding of the basic molecular biological mechanisms and potential roles of Maged1 as a regulator of various mESC properties.

Protective Effect of GIP against Monosodium Glutamate-Induced Ferroptosis in Mouse Hippocampal HT-22 Cells through the MAPK Signaling Pathway.

The effect of glucose-dependent insulinotropic polypeptide (GIP) on cells under oxidative stress induced by glutamate, a neurotransmitter, and the underlying molecular mechanisms were assessed in the present study. We found that in the pre-treatment of HT-22 cells with glutamate in a dose-dependent manner, intracellular ROS were excessively generated, and additional cell damage occurred in the form of lipid peroxidation. The neurotoxicity caused by excessive glutamate was found to be ferroptosis and not apoptosis. Other factors (GPx-4, Nrf2, Nox1 and Hspb1) involved in ferroptosis were also identified. In other words, it was confirmed that GIP increased the activity of sub-signalling molecules in the process of suppressing ferroptosis as an antioxidant and maintained a stable cell cycle even under glutamate-induced neurotoxicity. At the same time, in HT-22 cells exposed to ferroptosis as a result of excessive glutamate accumulation, GIP sustained cell viability by activating the mitogen-activated protein kinase (MAPK) signalling pathway. These results suggest that the overexpression of the GIP gene increases cell viability by regulating mechanisms related to cytotoxicity and reactive oxygen species production in hippocampal neuronal cell lines.

Emx2 regulates hair cell rearrangement but not positional identity within neuromasts.

Each hair cell (HC) precursor of zebrafish neuromasts divides to form two daughter HCs of opposite hair bundle orientations. Previously, we showed that transcription factor Emx2, expressed in only one of the daughter HCs, generates this bidirectional HC pattern (Jiang et al., 2017). Here, we asked whether Emx2 mediates this effect by changing location of hair bundle establishment or positions of HCs since daughter HCs are known to switch positions with each other. We showed this HC rearrangement, redefined as two processes named Rock and Roll, is required for positional acquisition of HCs. Apical protrusion formation of nascent HCs and planar polarity signaling are both important for the Rock and Roll. Emx2 facilitates Rock and Roll by delaying apical protrusion of its nascent HCs but it does not determine HCs' ultimate positions, indicating that Emx2 mediates bidirectional HC pattern by changing the location where hair bundle is established in HCs.

Directional selectivity of afferent neurons in zebrafish neuromasts is regulated by Emx2 in presynaptic hair cells.

The orientation of hair bundles on top of sensory hair cells (HCs) in neuromasts of the lateral line system allows fish to detect direction of water flow. Each neuromast shows hair bundles arranged in two opposing directions and each afferent neuron innervates only HCs of the same orientation. Previously, we showed that this opposition is established by expression of Emx2 in half of the HCs, where it mediates hair bundle reversal (Jiang et al., 2017). Here, we show that Emx2 also regulates neuronal selection: afferent neurons innervate either Emx2-positive or negative HCs. In emx2 knockout and gain-of-function neuromasts, all HCs are unidirectional and the innervation patterns and physiological responses of the afferent neurons are dependent on the presence or absence of Emx2. Our results indicate that Emx2 mediates the directional selectivity of neuromasts by two distinct processes: regulating hair bundle orientation in HCs and selecting afferent neuronal targets.

Inhibition of Migration and Invasion by Tet-1 Overexpression in Human Lung Carcinoma H460 Cells.

In the present study, we found that lung cancer cell line (H460 cells) expressing Tet1 showed higher levels of adhesion, and Tet1 inhibited H460 cell proliferation. In addition, these cells showed a significantly reduced ability of collagen degradation and Smad2/3 phosphorylation compared to controls. Furthermore, vimentin was found to be highly expressed in larger metastatic cancer area. Tet1 overexpression was reduced in the epithelial marker E-cadherin. Moreover, Tet1 repressed cancer cell metastasis in nude mice. Collectively, these findings suggest that Tet1 expression plays a critical role in metastasis of lung cancer cells by suppression of invasion and epithelial-mesenchymal transition (EMT).

Antibacterial Mechanism of (-)-Nortrachelogenin in Escherichia coli O157.

(-)-Nortrachelogenin is a lignan belonging to group of polyphenolic compounds. Its biological properties in mammalian cells are well-studied; however, its biological effects in microorganisms remain poorly understood. Its efficacy against pathogenic bacteria, including antibiotic-resistant strains, was investigated and it was found that bacteria are highly susceptible to the antibacterial effects of this compound. To investigate the antibacterial mode of action(s) against Escherichia coli O157, its effect on the penetration of SYTOX green into bacterial cells was assayed. The penetration of SYTOX Green into a bacterial cell is a measure of permeability of the plasma membrane. An increase in fluorescence intensity using bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)] and 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] was also observed, indicating membrane depolarization. Potassium ion efflux from the cytosol into the extracellular matrix showed that cellular damage due to (-)-nortrachelogenin treatment resulted in the loss of intracellular components. While cells were damaged by (-)-nortrachelogenin, large unilamellar vesicles containing fluorescein isothiocyanate-dextran were perturbed to migrate molecules between 3.3 and 4.8 nm. The release of calcein from giant unilamellar vesicles, occurring as a result of disruption in artificial membranes, was visualized. Taken together, our results indicate that (-)-nortrachelogenin exerts its antibacterial effect by disorganizing and perturbing the cytoplasmic membrane, demonstrating the potential of this compound as a candidate for antibiotic drug development.

Effect of estrogen on expression of prohibitin in white adipose tissue and liver of diet-induced obese rats.

Prohibitin (PHB) is a ubiquitously expressed and highly conserved protein that participates in diverse cellular processes, and its functions are linked to a variety of diseases. In the present study, to explore transcriptional activation and signaling pathways involved in PHB regulation in response to sex hormone treatment, we investigated the effects of estrogen (17-ß-estradiol, E2) on regulation of PHB in several metabolic tissues from male and female rats. Elevated expression of PHB was prominent in white adipose tissue (WAT) and the liver, and E2 stimulated PHB expression in both ND and HFD-fed rats. To further confirm the expression of PHB which was increased in WAT and the liver, we analyzed PHB expression levels in 3T3-L1 and C9 cells after the treatment of E2. Transcription and protein levels of PHB were dose-dependently increased by E2 treatment in both cell types, supporting our in vivo data. To further evaluate the possible role of E2 in elevation of PHB via estrogen receptors (ER), the potent ER inhibitor fulvestrant was treated to 3T3-L1 and C9 cells. Fulvestrant markedly suppressed both transcription and protein levels of PHB, suggesting that PHB expression in both tissues may be regulated through ERs. GeneMANIA, a predictive web interface, was used to show that Phb is regulated via the intracellular steroid hormone receptor signaling pathway, suggesting a role for ERs in expression of Phb as well as other metabolically important genes. Based on these results, we expect that targeting PHB would be a useful therapeutic approach for treatment of obesity.

Hepatic serum amyloid A1 aggravates T cell-mediated hepatitis by inducing chemokines via Toll-like receptor 2 in mice.

Serum amyloid A is a proinflammatory molecule that induces leukocyte infiltration and promotes neutrophil adhesion to endothelial cells under inflammatory conditions. The aim of this study was to examine whether Saa1 aggravates T cell-mediated hepatitis by inducing chemokines in a liver-specific, Saa1-overexpressing, transgenic (TG) mouse model. We generated TG mice in which Saa1 was overexpressed specifically in liver tissue. The chemokines monocyte chemotactic protein 1 (MCP1), MIP1α, MIP1ß, interferon γ-induced protein 10 (IP-10), and eotaxin were induced in Saa1 TG mice. After concanavalin A treatment, Saa1 expression was higher in Saa1 TG mice than in WT mice. More severe liver injury, increased hepatocyte apoptosis, and higher levels of hepatic enzymes were observed in Saa1 TG mice than in WT mice. Liver infiltration of CD4(+) T cells and macrophages increased after inducing hepatitis. Activation of T cells was higher in Saa1 TG mice than in WT mice, and the populations of Th17 cells and regulatory T cells were altered by overexpressing Saa1 in TG mice. Secretion of various cytokines, such as interferon γ, tumor necrosis factor α, and interleukin 6, increased in Saa1 TG mice. Injecting a Toll-like receptor 2 (TLR2) antagonist in vivo inhibited chemokine expression and IκBα phosphorylation and showed that the induction of chemokines by Saa1 was dependent on TLR2. Hepatic Saa1 accelerated T cell-mediated hepatitis by inducing chemokine production and activating T cells by TLR2. Therefore, Saa1 might be a novel inflammatory factor that acts as a chemokine modulator in hepatitis.

Critical role of Rgs19 in mouse embryonic stem cell proliferation and differentiation.

Mouse embryonic stem cells (ESCs) are self-renewing, pluripotent, and have the ability to differentiate into the three germ layers required to form all embryonic tissues. These properties are maintained by both intrinsic and extrinsic factors. Many studies have contributed to the understanding of the molecular signal transduction required for pluripotency and controlled differentiation. Such an understanding is important in the potential application of stem cells to cell therapy for disease, and thus there is an interest in understanding the cell cycle regulation, pluripotency, and differentiation of ESCs. The regulator of G protein signaling (RGS) family consists of over 20 members. Rgs19, one such protein, specifically interacts with Gαi to enhance its GTPase activity. Growth factor receptors use Gi proteins for signal transduction, and Rgs19 may thus be involved in the regulation of cell proliferation. In a previous gain-of-function study, Rgs19 overexpression was found to enhance proliferation in various cell types. Our data demonstrate a role for Rgs19 in the regulation of ESC differentiation. Based on the presence of Rgs19 in ESCs, the morphological and molecular properties of wild-type and Rgs19 +/- ESCs during LIF withdrawal, in vitro differentiation, and teratoma formation were compared. Our findings provide insight for the first time into the mechanisms involved in Rgs19 regulation of mouse ESC proliferation and differentiation.

Over-expression of Roquin aggravates T cell mediated hepatitis in transgenic mice using T cell specific promoter.

Chronic hepatitis is a major cause of liver cancer, so earlier treatment of hepatitis might be reducing liver cancer incidence. Hepatitis can be induced in mice by treatment with Concanavalin A (Con A); the resulting liver injury causes significant CD4(+) T cell activation and infiltration. In these T cells, Roquin, a ring-type E3 ubiquitin ligase, is activated. To investigate the role of Roquin, we examined Con A-induced liver injury and T cell infiltration in transgenic (Tg) mice overexpressing Roquin specifically in T cells. In Roquin Tg mice, Con A treatment caused greater increases in both the levels of liver injury enzymes and liver tissue apoptosis, as revealed by TUNEL and H&E staining, than wild type (WT) mice. Further, Roquin Tg mice respond to Con A treatment with greater increases in the T cell population, particularly Th17 cells, though Treg cell counts are lower. Roquin overexpression also enhances increases in pro-inflammatory cytokines, including IFN-γ, TNF-α and IL-6, upon liver injury. Furthermore, Roquin regulates the immune response and apoptosis in Con A induced hepatitis via STATs, Bax and Bcl2. These findings suggest that over-expression of Roquin exacerbates T-cell mediated hepatitis.

Gestational loss and growth restriction by angiogenic defects in placental growth factor transgenic mice.

OBJECTIVE: Angiogenesis is an important biological process during development, reproduction, and in immune responses. Placental growth factor (PlGF) is a member of vascular endothelial growth factor that is critical for angiogenesis and vasculogenesis. We generated transgenic mice overexpressing PlGF in specifically T cells using the human CD2-promoter to investigate the effects of PlGF overexpression. APPROACH AND RESULTS: Transgenic mice were difficult to obtain owing to high lethality; for this reason, we investigated why gestational loss occurred in these transgenic mice. Here, we report that placenta detachment and inhibition of angiogenesis occurred in PlGF transgenic mice during the gestational period. Moreover, even when transgenic mice were born, their growth was restricted. CONCLUSIONS: Conclusively, PlGF overexpression prevents angiogenesis by inhibiting Braf, extracellular signal-regulated kinase activation, and downregulation of HIF-1α in the mouse placenta. Furthermore, it affected regulatory T cells, which are important for maintenance of pregnancy.

Overexpression of Jazf1 reduces body weight gain and regulates lipid metabolism in high fat diet.

Jazf1 is a 27 kDa nuclear protein containing three putative zinc finger motifs that is associated with diabetes mellitus and prostate cancer; however, little is known about the role that this gene plays in regulation of metabolism. Recent evidence indicates that Jazf1 transcription factors bind to the nuclear orphan receptor TR4. This receptor regulates PEPCK, the key enzyme involved in gluconeogenesis. To elucidate Jazf1's role in metabolism, we fed a 60% fat diet for up to 15 weeks. In Jazf1 overexpression mice, weight gain was found to be significantly decreased. The expression of Jazf1 in the liver also suppressed lipid accumulation and decreased droplet size. These results suggest that Jazf1 plays a critical role in the regulation of lipid homeostasis. Finally, Jazf1 may provide a new therapeutic target in the management of obesity and diabetes.

Enforced expression of roquin protein in T cells exacerbates the incidence and severity of experimental arthritis.

To investigate the role of Roquin, a RING-type ubiquitin ligase family member, we used transgenic mice with enforced Roquin expression in T cells, with collagen-induced arthritis (CIA). Wild-type (WT) and Roquin transgenic (Tg) mice were immunized with bovine type II collagen (CII). Arthritis severity was evaluated by clinical score; histopathologic CIA severity; proinflammatory and anti-inflammatory cytokine levels; anti-CII antibody levels; and populations of Th1, Th2, germinal center B cells, and follicular helper T cells in CIA. T cell proliferation in vitro and cytokine levels were determined to assess the response to CII. Roquin Tg mice developed more severe CIA and joint destruction compared with WT mice. Production of TNF-α, IFN-γ, IL-6, and pathogenic anti-collagen CII-specific IgG and IgG2a antibodies was increased in Roquin Tg mice. In addition, in vitro T cell assays showed increased proliferation and proinflammatory cytokine production in response to CII as a result of enforced Roquin expression in T cells. Furthermore, the Th1/Th2 balance was altered by an increased Th1 and decreased Th2 population. These findings suggest that overexpression of Roquin exacerbates the development of CIA and that enforced expression of Roquin in T cells may promote autoimmune diseases such as CIA.

Rgs19 regulates mouse palatal fusion by modulating cell proliferation and apoptosis in the MEE.

Palatal development is one of the critical events in craniofacial morphogenesis. During fusion of the palatal shelves, removal of the midline epithelial seam (MES) is a fundamental process for achieving proper morphogenesis of the palate. The reported mechanisms for removing the MES are the processes of apoptosis, migration or general epithelial-to-mesenchymal transition (EMT) through modulations of various signaling molecules including Wnt signaling. RGS19, a regulator of the G protein signaling (RGS) family, interacts selectively with the specific α subunits of the G proteins (Gαi, Gαq) and enhances their GTPase activity. Rgs19 was reported to be a modulator of the Wnt signaling pathway. In mouse palatogenesis, the restricted epithelial expression pattern of Rgs19 was examined in the palatal shelves, where expression of Wnt11 was observed. Based on these specific expression patterns of Rgs19 in the palatal shelves, the present study examined the detailed developmental function of Rgs19 using AS-ODN treatments during in vitro palate organ cultivations as a loss-of-function study. After the knockdown of Rgs19, the morphological changes in the palatal shelves was examined carefully using a computer-aided three dimensional reconstruction method and the altered expression patterns of related signaling molecules were evaluated using genome wide screening methods. RT-qPCR and in situ hybridization methods were also used to confirm these array results. These morphological and molecular examinations suggested that Rgs19 plays important roles in palatal fusion through the degradation of MES via activation of the palatal fusion related and apoptotic related genes. Overall, inhibition of the proliferation related and Wnt responsive genes by Rgs19 are required for proper palatal fusion.

Over-expression of extracellular superoxide dismutase in mouse synovial tissue attenuates the inflammatory arthritis.

Oxidative stress such as reactive oxygen species (ROS) within the inflamed joint have been indicated as being involved as inflammatory mediators in the induction of arthritis. Correlations between extracellular- superoxide dismutase (EC-SOD) and inflammatory arthritis have been shown in several animal models of RA. However, there is a question whether the over-expression of EC-SOD on arthritic joint also could suppress the progression of disease or not. In the present study, the effect on the synovial tissue of experimental arthritis was investigated using EC-SOD over-expressing transgenic mice. The over-expression of EC- SOD in joint tissue was confirmed by RT-PCR and immunohistochemistry. The degree of the inflammation in EC-SOD transgenic mice was suppressed in the collagen-induced arthritis model. In a cytokine assay, the production of pro-inflammatory cytokines such as, IL-1ß, TNFα, and matrix metalloproteinases (MMPs) was decreased in fibroblast-like synoviocyte (FLS) but not in peripheral blood. Histological examination also showed repressed cartilage destruction and bone in EC-SOD transgenic mice. In conclusion, these data suggest that the over-expression of EC-SOD in FLS contributes to the activation of FLS and protection from joint destruction by depressing the production of the pro-inflammatory cytokines and MMPs. These results provide EC-SOD transgenic mice with a useful animal model for inflammatory arthritis research.

Regulation of inflammatory responses and fibroblast-like synoviocyte apoptosis by calcineurin-binding protein 1 in mice with collagen-induced arthritis.

OBJECTIVE: Calcineurin-binding protein 1 (CABIN-1) regulates calcineurin phosphatase activity as well as the activation, apoptosis, and inflammatory responses of fibroblast-like synoviocytes (FLS), which actively participate in the chronic inflammatory responses in rheumatoid arthritis (RA). However, the mechanism of action of CABIN-1 in FLS apoptosis is not clear. This study was undertaken to define the regulatory role of CABIN-1 in FLS from mice with collagen-induced arthritis (CIA). METHODS: Transgenic mice overexpressing human CABIN-1 in joint tissue under the control of a type II collagen promoter were generated. Expression of human CABIN-1 (hCABIN-1) in joints and FLS was determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. The expression of cytokines, matrix metalloproteinases (MMPs), and apoptosis-related genes in FLS was determined by enzyme-linked immunosorbent assay, gelatin zymography, and RT-PCR, respectively. Joints were stained with hematoxylin and eosin and with tartrate-resistant acid phosphatase for histologic analysis. RESULTS: Human CABIN-1-transgenic mice with CIA had less severe arthritis than wild-type mice with CIA, as assessed according to hind paw thickness and histologic features. The milder arthritis was accompanied by significantly enhanced apoptosis in transgenic mice, evidenced by a significantly greater number of TUNEL-positive cells in synovial tissue. Expression of inflammatory cytokines and MMPs in the transgenic mice with CIA was reduced, and they exhibited decreased Akt activation and increased expression of p53, caspase 3, caspase 9, and Bax. CONCLUSION: Our findings demonstrate that hCABIN-1 plays a critical role in promoting apoptosis of FLS and in attenuating inflammation and cartilage and bone destruction in RA. These results help elucidate the pathogenic mechanisms of RA and suggest that CABIN-1 is a potential target for treatment of this disease.

Tissue-specific expression of human calcineurin-binding protein 1 in mouse synovial tissue can suppress inflammatory arthritis.

Calcineurin (CN) is a calcium- and calmodulin-dependent serine/threonine phosphatase. In immune cells, CN controls the activity of a wide range of transcription factors, including nuclear factor of activated T, nuclear factor-kappa B, c-fos, and Elk-1. CN plays an important role in synoviocyte activation and arthritis progression in vivo and this function is tightly linked to dysregulated intracellular Ca(2+) store and Ca(2+) response triggered by proinflammatory cytokines. In the present study, transgenic mice expressing human calcineurin-binding protein 1 (hCabin1) were generated, driven by type II collagen promoter, and the efficiency of these mice was investigated by experimental arthritis. These transgenic mice successfully expressed hCabin1 in joint tissue as well as other organs such as liver, heart, and brain. The overexpression of hCabin1 reduced the disease severity during collagen-induced arthritis. In fibroblast-like synoviocytes (FLSs) from hCabin1 transgenic mice, the productions of these cytokines, including interleukin (IL)-2, IL-4, and IFN-γ, were decreased and matrix metalloproteinases were also depressed in transgenic mice FLS. In addition, these effects were only found in the joint tissue, which is a major inflammation site. These findings will provide a better knowledge of the pathogenic mechanisms of rheumatoid arthritis and a potential animal model of the chronic inflammatory conditions, including atherosclerosis and transplantation.

The role of Roquin overexpression in the modulation of signaling during in vitro and ex vivo T-cell activation.

The T-cell receptor (TCR) engages with an antigen and initiates a signaling cascade that leads to the activation of transcription factors. Roquin, a protein encoded by the RC3H1 gene and characterized as an immune regulator, was recently identified as a novel RING-type ubiquitin ligase family member, but the mechanisms by which Roquin regulates T-cell responses are unclear. We used the EL-4 murine lymphoma cell line to elucidate the role of Roquin in vitro. Roquin-overexpressing EL-4 cells became hyper-responsive after anti-CD3/CD28 stimulation in vitro and were a major source of the cytokines IL-2 and TNF-α. Upon activation, these cells showed particularly enhanced production of IL-2 and TNF-α. To clarify the important role played by Roquin in T-cell responses ex vivo, we generated T-cell-specific Roquin transgenic (Tg) mice. Roquin-Tg CD4(+) T-cells showed enhanced production of IL-2 and TNF-α in response to TCR stimulation with anti-CD28 co-stimulation. Further studies are necessary to investigate the role of Roquin in the regulation of primary T-cell activation, survival, and differentiation.