TASL mediates keratinocyte differentiation by regulating intracellular calcium levels and lysosomal function.

Maintaining epidermal homeostasis relies on a tightly organized process of proliferation and differentiation of keratinocytes. While past studies have primarily focused on calcium regulation in keratinocyte differentiation, recent research has shed light on the crucial role of lysosome dysfunction in this process. TLR adaptor interacting with SLC15A4 on the lysosome (TASL) plays a role in regulating pH within the endo-lysosome. However, the specific role of TASL in keratinocyte differentiation and its potential impact on proliferation remains elusive. In our study, we discovered that TASL deficiency hinders the proliferation and migration of keratinocytes by inducing G1/S cell cycle arrest. Also, TASL deficiency disrupts proper differentiation process in TASL knockout human keratinocyte cell line (HaCaT) by affecting lysosomal function. Additionally, our research into calcium-induced differentiation showed that TASL deficiency affects calcium modulation, which is essential for keratinocyte regulation. These findings unveil a novel role of TASL in the proliferation and differentiation of keratinocytes, providing new insights into the intricate regulatory mechanisms of keratinocyte biology.

Chitinase 3-like 1 induces cancer cell migration in solitary fibrous tumors.

Solitary fibrous tumor (SFT) is a rare mesenchymal tumor that is diagnosed through the detection of the NAB2-STAT6 fusion gene. SFT rarely progresses to malignant tumors; however, metastasis is exhibited in approximately 20% of patients with SFT. In this study, we found that chitinase 3-like 1 (CHI3L1), which induces cancer cell migration, was upregulated in NIH-3T3 cells that were transfected with the NAB2-STAT6 fusion gene. Moreover, the expression levels of the migration markers MMP2 and MMP9 were increased and the p-Akt level was also upregulated. In addition, it was observed that when CHI3L1 siRNA was transfected into NAB2-STAT6-transfected cells, cell migration and proliferation were reduced. Therefore, this study demonstrated that CHI3L1 activates Akt signaling to induce cell migration.

Enhanced glutathione content improves lateral root development and grain yield in rice plants.

KEY MESSAGE: Enhanced glutathione content improves lateral root development by positively regulating the transcripts of root development genes responsive to glutathione treatment, thereby increasing the overall productivity of rice plants. Glutathione is primarily known as a cellular antioxidant molecule, but its role in lateral root development in rice plants has not been elucidated. Here, we have investigated its role in lateral root development of rice Oryza sativa L. Exogenous glutathione (GSH) promoted both the number and length of lateral roots in rice, and the GSH biosynthesis inhibitor buthionine sulfoximine (BSO) significantly reduced these parameters, compared to untreated plants. The inhibition by BSO was reversed with exogenous GSH. Transcript profiling by RNA-seq revealed that expression of the transcription factor genes DREB and ERF and the hormone-related genes AOS, LOX, JAZ, and SAUR were significantly downregulated in the BSO-treated plants and, in contrast, upregulated in plants treated with GSH and with GSH and BSO together. We generated OsGS-overexpressing transgenic plants in which the transgene is controlled by the abiotic-stress-inducible OsRab21 promoter to study the effect of endogenously increased GSH levels. In cold stress, transgenic rice plants enhanced stress tolerance and lateral root development by maintaining redox homeostasis and improving upregulating the expression of transcription factors and hormone-related genes involved in lateral root development. We observed improved root growth of OsGS-overexpressing plants in paddy fields compared to the wild-type controls. These traits may have alleviated transplanting stress during early growth in the field and accounted for the increased productivity. These results provide information and perspectives on the role of GSH in gene expression, lateral root development, and grain yield in rice.

NAB2-STAT6 fusion protein mediates cell proliferation and oncogenic progression via EGR-1 regulation.

Solitary fibrous tumors are rare mesenchymal tumors derived from soft tissues and vascular walls. NAB2-STAT6 fusion gene serves as a marker gene for this disease and consists of the truncated repressor domain of NGFI-A-Binding protein 2 (NAB2) and the intact activation domain of STAT6. In this study, we found that EGR-1 and the proliferation-related EGR-1 target gene IGF2 were upregulated in NIH-3T3 cells transfected with NAB2-STAT6. Additionally, p-Rb (Ser795) and cyclin D1 levels were upregulated, and cell proliferation was also enhanced. We identified that treatment with the IGF2 inhibitor reduced cell proliferation in NIH-3T3 cells transfected with NAB2-STAT6. The oncogenic progression was enhanced in NIH-3T3 cells transfected with NAB2-STAT6 compared with those transfected with the empty vector. Taken together, our study suggests that the NAB2-STAT6 fusion gene is associated with cell proliferation through EGR-1 transcriptional expression and IGF2 can be a drug target for the treatment of solitary fibrous tumors.

Hepatic serum amyloid A1 upregulates interleukin-17 (IL-17) in γδ T cells through Toll-like receptor 2 and is associated with psoriatic symptoms in transgenic mice.

Serum amyloid A (SAA) is an acute phase protein with pro-inflammatory cytokine-like properties. Recent studies have revealed that SAA promoted interleukin-17 (IL-17) production by various cells, including γδ T cells. γδ T cells are innate immune cells and express Toll-like receptor 2 (TLR2) on their surface, which is one of the SAA receptors. In this study, we investigated the relationship between γδ T cells and SAA1 through TLR2, by using hepatic SAA1-overexpressing transgenic (TG) mice. By injecting CU-CPT22, which is a TLR2 inhibitor, into the mice, we confirmed that SAA1 induced IL-17 in γδ T cells through TLR2. In vitro studies have confirmed that SAA1 increased IL-17 secretion in γδ T cells in combination with IL-23. We also observed a thickened epidermis layer and granulocyte penetration into the skin similar to the pathology of psoriasis in TG mice. In addition, strongly expressed SAA1 and penetration of γδ T cells in the skin of TG mice were detected. The exacerbation of psoriasis is associated with an increase in IL-17 levels. Therefore, these symptoms were induced by IL-17-producing γδ T cells increased by SAA1. Our study confirmed that SAA1 was a prominent protein that increased IL-17 levels through TLR2 in γδ T cells, confirming the possibility that SAA1 may exacerbate inflammatory diseases through γδ T cells.

TRIB2 regulates the differentiation of MLL-TET1 transduced myeloid progenitor cells.

The function and mechanism of action of MLL-TET1 (MT1) fusion protein in hematological cells are unclear and require further investigation. In the present study, we found that the MT1 fusion protein attenuated the expression of Cebpa, Csf1r, and Cd11b and inhibited the differentiation of myeloid progenitor cells. Increased binding of the MT1 fusion protein to the Trib2 promoter upregulated Trib2 mRNA and protein expression and downregulated Cebpa expression. Trib2 knockdown relieved the inhibition of myeloid cell differentiation induced by the MT1 fusion protein. Thus, TRIB2 is important for the survival of leukemia cells during MT1-related leukemogenesis and is important in maintaining differentiation blockade of leukemic cells. KEY MESSAGES: • MLL-TET1 fusion decreases the 5-hmC levels in the myeloid progenitor cells. • MLL-TET1 fusion inhibits myeloid differentiation through decreased expression of Cebpa. • MLL-TET1 fusion blocks the differentiation of the myeloid progenitor cells by overexpressing Trib2. • Knockdown of Trib2 in MLL-TET1 transduced cells induces myeloid differentiation.

Tet1 overexpression leads to anxiety-like behavior and enhanced fear memories via the activation of calcium-dependent cascade through Egr1 expression in mice.

Ten-eleven translocation methylcytosine dioxygenase 1 (Tet1) initiates DNA demethylation by converting 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) at CpG-rich regions of genes, which have key roles in adult neurogenesis and memory. In addition, the overexpression of Tet1 with 5-hmC alteration in patients with psychosis has also been reported, for instance in schizophrenia and bipolar disorders. The mechanism underlying Tet1 overexpression in the brain; however, is still elusive. In the present study, we found that Tet1-transgenic (Tet1-TG) mice displayed abnormal behaviors involving elevated anxiety and enhanced fear memories. We confirmed that Tet1 overexpression affected adult neurogenesis with oligodendrocyte differentiation in the hippocampal dentate gyrus of Tet1-TG mice. In addition, Tet1 overexpression induced the elevated expression of immediate early genes, such as Egr1, c-fos, Arc, and Bdnf, followed by the activation of intracellular calcium signals (i.e., CamKII, ERK, and CREB) in prefrontal and hippocampal neurons. The expression of GABA receptor subunits (Gabra2 and Gabra4) fluctuated in the prefrontal cortex and hippocampus. We evaluated the effects of Tet1 overexpression on intracellular calcium-dependent cascades by activating the Egr1 promoter in vitro Tet1 enhanced Egr1 expression, which may have led to alterations in Gabra2 and Gabra4 expression in neurons. Taken together, we suggest that the Tet1 overexpression in our Tet1-TG mice can be applied as an effective model for studying various stress-related diseases that show hyperactivation of intracellular calcium-dependent cascades in the brain.-Kwon, W., Kim, H.-S., Jeong, J., Sung, Y., Choi, M., Park, S., Lee, J., Jang, S., Kim, S. H., Lee, S., Kim, M. O., Ryoo, Z. Y. Tet1 overexpression leads to anxiety-like behavior and enhanced fear memories via the activation of calcium-dependent cascade through Egr1 expression in mice.

hMAGEA2 promotes progression of breast cancer by regulating Akt and Erk1/2 pathways.

Breast cancer is the most abundant cancer worldwide and a severe problem for women. Notably, breast cancer has a high mortality rate, mainly because of tumor progression and metastasis. Triple-negative breast cancer (TNBC) is highly progressive and lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Therefore, there are no established therapeutic targets against TNBC. In this study, we investigated whether the expression of human melanoma-associated antigen A2 (MAGEA2) is associated with TNBC. We found that hMAGEA2 is significantly overexpressed in human TNBC tissues; we also observed oncogenic properties using TNBC cell lines (MDA-MB-231 and MDA-MB-468). The overexpression of hMAGEA2 in MDA-MB-231 cell line showed dramatically increased cellular proliferation, colony formation, invasion, and xenograft tumor formation and growth. Conversely, knockdown of hMAEGA2 in MDA-MB-468 cell line suppressed cellular proliferation, colony formation, and xenograft tumor formation. Additionally, we showed that hMAGEA2 regulated the activation of Akt and Erk1/2 signaling pathways. These data indicate that hMAGEA2 is important for progression of TNBC and may serve as a novel molecular therapeutic target.

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).

Mesenchymal signaling in dorsoventral differentiation of palatal epithelium.

After palatal fusion, the dorsal and ventral epithelia of the palatal shelf differentiate into the nasal and oral mucosa, respectively. The tissue-specific differentiation of palatal epithelia along the dorsal-ventral axis is regulated by the signaling molecules expressed in the underlying mesenchyme. Thus, as in many other epithelial organs, differentiation relies on epithelial-mesenchymal interactions. To screen for region-specific mesenchymal signaling molecules that determine the fate of the palatal epithelia, we employed a laser microdissection (LMD) method. LMD allowed us to collect region-specific mesenchymal tissues at E13, prior to palatal fusion and the development of distinct dorsal and ventral epithelial morphology. Genome-wide screening was performed on the tissues collected using LMD to identify candidate mesenchymal signaling molecules. The microarray results were validated using real-time quantitative (qPCR) and in situ hybridization methods. The developmental role and interactions of the candidate genes were evaluated in in vitro-cultivated E13 palates using an anti-sense oligodeoxynucleotide (AS-ODN)-based loss-of-function approach. Apparent changes in the expression patterns of Runt-related transcription factor 2 (Runx2) and LIM homeobox 8 (Lhx8) were observed after knocking down each gene. Knock-down of Runx2 and Lhx8 also altered the immunolocalization pattern of cytokeratin18 (CK18), an established marker for nasal epithelium. These results were confirmed using Runx2 heterozygote mice. The mesenchymal signaling molecules Runx2 and Lhx8, which possess region-specific expression patterns along the dorsoventral axis, functionally interact to regulate the cellular and molecular characteristics of dorsal and ventral epithelia, suggesting that mesenchymal signaling molecules determine the dorsoventral fate of epithelial structures in the developing palate.

RGS19 converts iron deprivation stress into a growth-inhibitory signal.

Iron chelation is a promising therapeutic strategy for cancer that works, in part, by inducing overexpression of N-myc downstream-regulated gene 1 protein (NDRG1), a known growth inhibitor and metastasis suppressor. However, details of the signaling cascades that convert physical stress into a biological response remain elusive. We investigated the role of RGS19, a regulator of G-protein signaling, in iron chelator-induced NDRG1 overexpression in HeLa cells. Knockdown of RGS19 diminished the expression of genes involved in desferrioxamine (DFO)-induced growth inhibition. Conversely, overexpression of RGS19 enhanced the expression of these genes. Moreover, overexpression of RGS19 reduced cell viability. Overexpression of G-protein alpha subunit i3 (Gαi3) repressed the induction of NDRG1 expression. Selective inhibition of downstream targets of Gαi3 abrogated DFO-induced overexpression of NDRG1. DFO protected RGS19 from proteolysis induced by GAIP interacting protein N terminus (GIPN); moreover, an iron-deficient RGS19 mutant was stable in the presence of GIPN and retained GTPase-activating protein activity. RGS19 was co-purified with iron and showed unique UV-absorption characteristics frequently observed in iron-binding proteins. This study demonstrates that RGS19 senses cellular iron availability and is stabilized under iron-depleted conditions, resulting in the induction of a growth-inhibitory signal.

Gene expression profiles reveal effect of a high-fat diet on the development of white and brown adipose tissues.

Because of the recent discovery of brown adipose tissues tissue in adult humans, brown adipose tissues have garnered additional attention. Many studies have attempted to transform the precursor cells within the white adipocyte cultures to Brite (brown-in-white) cells by using genomic modification or pharmacological activation in order to determine the therapeutic effect of obesity. However, genome-scale analysis of the genetic factors governing the development of white and brown adipose tissues remains incomplete. In order to identify the key genes that regulate the development of white and brown adipose tissues in mice, a transcriptome analysis was performed on the adipose tissues. Network analysis of differentially expressed genes indicated that Trim30 and Ucp3 play pivotal roles in energy balance and glucose homeostasis. In addition, it was discovered that identical biological processes and pathways in the white and brown adipose tissues might be regulated by different genes. Trim30 and Ucp3 might be used as genetic markers to precisely represent the stage of obesity during the early and late stages of adipose tissue development, respectively. These results may provide a stepping-stone for future obesity-related studies.

Induction of apoptosis by obovatol as a novel therapeutic strategy for acute myeloid leukemia.

Obovatol, a compound isolated from the bark cortex of Magnolia officinalis (cortex Magnoliae officinalis; M. officinalis), has been studied for use in the treatment of solid cancers. However, the mechanisms of action and the effects of obovatol against acute myeloid leukemia (AML) remain unclear and require further investigation. Therefore, this study was conducted using a human AML cell line (MM6). Obovatol increased pro-apoptotic (Bax) and decreased anti-apoptotic (Bcl-2) protein expression, resulting in caspase-3 and caspase-9 activation measured by caspase-Glo 3/7 assay. Furthermore, obovatol activated the mitogen-activated protein kinase (MAPK) signaling pathway [c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38] and inhibited the activation of the nuclear factor-κB (NF-κB) signaling pathway analyzed by western blot analysis. Taken together, these findings provide evidence that obovatol inhibits cell proliferation in AML and induces apoptosis through the activation of the MAPK pathway in addition to the intrinsic apoptotic pathway. In addition, obovatol suppressed the expression of mixed-lineage leukemia (MLL) target genes by inhibiting the activation of the NF-κB pathway. Therefore, these results suggest that obovatol may have potential for use in the treatment of leukemia.

Regulation of HOXA9 activity by predominant expression of DACH1 against C/EBPα and GATA-1 in myeloid leukemia with MLL-AF9.

Although MLL-AF9 caused by the chromosomal translocation t(9;11) has a critical role in acute myeloid leukemia, the molecular pathogenesis is poorly understood. Here, we identified that the cell fate determination factor DACH1 is directly up-regulated by MLL-AF9. Recently we showed that the forced expression of DACH1 in myeloid cells induced p27(Kip1) and repressed p21(Cip1), which is a pivotal characteristic of the myeloid progenitor. Consistent with our previous study, ectopic expression of DACH1 contributed to the maintenance of colonogenic activity and blocked the differentiation of myeloid progenitors. Moreover, we here identified an endogenous HOXA9-DACH1 complex mediated by the carboxyl terminus of DACH1 in t(9;11) leukemia cells. qRT-PCR revealed that DACH1 has a stronger transcription-promoting activity with HOXA9 than does PBX2 with HOXA9. Furthermore, C/EBPα and GATA-1 can directly bind to the promoter of DACH1 and act as a transcriptional suppressor. Expression of DACH1 is down-regulated during myeloid differentiation and shows an inverse pattern compared to C/EBPα and GATA-1 expression. However, ectopic expression of C/EBPα and/or GATA-1 could not abrogate the over-expression of DACH1 induced by MLL-AF9. Therefore, we postulate that the inability of C/EBPα and GATA-1 to down-regulate DACH1 expression induced by MLL-AF9 during myeloid differentiation may contribute to t(9;11) leukemogenesis.

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.

Proteome analysis of developing mice diastema region.

Different from humans, who have a continuous dentition of teeth, mice have only three molars and one incisor separated by a toothless region called the diastema in the hemi mandibular arch. Although tooth buds form in the embryonic diastema, they regress and do not develop into teeth. In this study, we evaluated the proteins that modulate the diastema formation through comparative analysis with molar-forming tissue by liquid chromatography-tandem mass spectroscopy (LC-MS/MS) proteome analysis. From the comparative and semi-quantitative proteome analysis, we identified 147 up- and 173 down-regulated proteins in the diastema compared to the molar forming proteins. Based on this proteome analysis, we selected and evaluated two candidate proteins, EMERIN and RAB7A, as diastema tissue specific markers. This study provides the first list of proteins that were detected in the mouse embryonic diastema region, which will be useful to understand the mechanisms of tooth development.

DACH1 regulates cell cycle progression of myeloid cells through the control of cyclin D, Cdk 4/6 and p21Cip1.

The cell-fate determination factor Dachshund, a component of the Retinal Determination Gene Network (RDGN), has a role in breast tumor proliferation through the repression of cyclin D1 and several key regulators of embryonic stem cell function, such as Nanog and Sox2. However, little is known about the role of DACH1 in a myeloid lineage as a cell cycle regulator. Here, we identified the differential expression levels of extensive cell cycle regulators controlled by DACH1 in myeloid progenitor cells. The forced expression of DACH1 induced p27(Kip1) and repressed p21(Cip1), which is a pivotal characteristic of the myeloid progenitor. Furthermore, DACH1 significantly increased the expression of cyclin D1, D3, F, and Cdk 1, 4, and 6 in myeloid progenitor cells. The knockdown of DACH1 blocked the cell cycle progression of HL-60 promyeloblastic cells through the decrease of cyclin D1, D3, F, and Cdk 1, 4, and 6 and increase in p21(Cip1), which in turn decreased the phosphorylation of the Rb protein. The expression of Sox2, Oct4, and Klf4 was significantly up-regulated by the forced expression of DACH1 in mouse myeloid progenitor cells.

Hepatic transcription response to high-fat treatment in mice: microarray comparison of individual vs. pooled RNA samples.

Microarray analysis is an important tool in studying gene expression profiles in genomic research. Despite many concerns raised, mRNA samples are often pooled in microarray experiments to reduce the cost and complexity of analysis of transcript profiling. This study reports the results of microarray experiments designed to compare effects of pooling RNA samples and its impact on identifying profiles of mRNA transcripts and differentially expressed genes (DEGs) in the liver of C57BL/6J mice fed normal and high-fat diet. Pearson's correlation coefficient of transcripts between pooled and non-pooled RNA samples was 0.98 to 1.0. The impact of pooled vs. non-pooled RNA samples was also compared by number of transcripts or DEGs. Agreement of significant genes between pooled and non-pooled sets was fairly desirable based on t-test <0.05 and/or signal intensity ≥ 2-fold. Biological process profile and the correlation coefficiency of fold change in the hepatic gene transcripts between pooled and non-pooled samples were also higher than 0.97. This suggests that pooling hepatic RNA samples can reflect the expression pattern of individual samples, and that properly constructed pools can provide nearly identical measures of transcription response to individual RNA sample.

Detection of low-abundant novel transcripts in mouse hematopoietic stem cells.

Gene expression profiles of hematopoietic stem cells (HSCs) provide clues for understanding molecular mechanisms of HSC behavior, including self-renewal and differentiation. We took advantage of serial analysis of gene expression (SAGE) to identify medium- and low-abundant transcripts expressed in HSCs/hematopoietic progenitor cells (HPCs). Among a total of 31,380 unique transcripts, 17,326 (55%) correspond to known genes and, 14,054 (45%) are low-copy transcripts that have no matches to currently known genes. Among the former class, 3,899 (23%) were alternatively spliced transcripts and 3,754 (22%) represent anti-sense transcripts from known genes. Mapping of the SAGE tags to the mouse genome showed that differences in gene expression exist among chromosomes. In addition, comparison of the HSCs/HPCs SAGE data to that of myeloid progenitor cells revealed that massive genetic reprogramming occurs in hematopoietic cell differentiation. Our results demonstrate a previously unrecognized complexity of gene expression in HSCs/HPCs, and indicate the need for further efforts to fully identify and characterize the transcripts expressed in this cell type.