The secreted protein Amuc_1409 from Akkermansia muciniphila improves gut health through intestinal stem cell regulation

Akkermansia muciniphila has received great attention because of its beneficial roles in gut health by regulating gut immunity, promoting intestinal epithelial development, and improving barrier integrity. However, A. muciniphila-derived functional molecules regulating gut health are not well understood. Microbiome-secreted proteins act as key arbitrators of host-microbiome crosstalk through interactions with host cells in the gut and are important for understanding host-microbiome relationships. Herein, we report the biological function of Amuc_1409, a previously uncharacterised A. muciniphila-secreted protein. Amuc_1409 increased intestinal stem cell (ISC) proliferation and regeneration in ex vivo intestinal organoids and in vivo models of radiation- or chemotherapeutic drug-induced intestinal injury and natural aging with male mice. Mechanistically, Amuc_1409 promoted E-cadherin/β-catenin complex dissociation via interaction with E-cadherin, resulting in the activation of Wnt/β-catenin signaling. Our results demonstrate that Amuc_1409 plays a crucial role in intestinal homeostasis by regulating ISC activity in an E-cadherin-dependent manner and is a promising biomolecule for improving and maintaining gut health.

1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (EC-18) Modulates Th2 Immunity through Attenuation of IL-4 Expression

Controlling balance between T-helper type 1 (Th1) and T-helper type 2 (Th2) plays a pivotal role in maintaining the biological rhythm of Th1/Th2 and circumventing diseases caused by Th1/Th2 imbalance. Interleukin 4 (IL-4) is a Th2-type cytokine and often associated with hypersensitivity-related diseases such as atopic dermatitis and allergies when overexpressed. In this study, we have tried to elucidate the function of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (EC-18) as an essential modulator of Th1/Th2 balance. EC-18 has showed an inhibitory effect on the production of IL-4 in a dose-dependent manner. RT-PCR analysis has proved EC-18 affect the transcription of IL-4. By analyzing the phosphorylation status of Signal transducer and activator of transcription 6 (STAT6), which is a transcriptional activator of IL-4 expression, we discovered that EC-18 induced the decrease of STAT6 activity in several stimulated cell lines, which was also showed in STAT6 reporter analysis. Co-treatment of EC-18 significantly weakened atopy-like phenotypes in mice treated with an allergen. Collectively, our results suggest that EC-18 is a potent Th2 modulating factor by regulating the transcription of IL-4 via STAT6 modulation, and could be developed for immune-modulatory therapeutics.

Collagen triple helix repeat containing-1 (CTHRC1) expression in invasive ductal carcinoma of the breast: the impact on prognosis and correlation to clinicopathologic features

CTHRC1 has been known as a regulator of collagen expression and cell migration. The aim of this research was to clarify the clinicopathologic significance of CTHRC1 expression in human breast cancer. 22 cases of breast cancer tissues, randomly selected from clinically diagnosed patients, showed a significant increase of CTHRC1 mRNA expression compared to the normal tissue from the same patients using RT-PCR and real-time PCR. Additionally we investigated breast cancers from 189 patients by immunohistochemistry (IHC). A high level of CTHRC1 expression was observed in 111 (58.7 %) out of 189 breast cancer patients and the expression was significantly correlated with histologic grade (P = 0.026), nodal status (P < 0.001), and TNM pathologic stage (P = 0.002). High CTHRC1 expression was associated with a shorter recurrence free survival (P = 0.008). Taken together, the results showed that CTHRC1 over-expression was significantly associated with clinicopathological factors of poor prognosis in invasive ductal carcinoma. CTHRC1 could be used as a supplementary prognostic biomarker and a potential therapeutic target in breast cancer.

Expression of endothelial cell-specific molecule-1 regulated by hypoxia inducible factor-1α in human colon carcinoma: impact of ESM-1 on prognosis and its correlation with clinicopathological features

Based on a previous finding that endothelial cell-specific molecule-1 (ESM-1) is a potential serum marker for colorectal cancer (CRC), the aim of this study was to clarify the clinicopathological significance of ESM-1 expression in CRC, and to explore the correlation between ESM-1 and HIF-1α in the tumorigenesis of CRC related to hypoxic conditions. ESM-1 mRNA expression was examined in CRC and corresponding normal mucosal tissues by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time RT-PCR. This experiment confirmed that ESM-1 levels were high in CRC. We screened the tissue samples of 143 CRC patients. By immunohistochemistry, we determined that the ESM-1 immunoreactivity was significantly correlated with the tumor size, depth of invasion, nodal status, distant metastasis and Dukes' stage, and was an independent prognostic factor for disease recurrence and worse survival outcome (P=0.001). The modulation of ESM-1 under hypoxia was investigated, and it was confirmed that ESM-1 expression was induced by HIF1-α and significantly attenuated by small interfering RNA (siRNA) targeting HIF-1α in CRC cells. These results showed that ESM-1 is significantly overexpressed, which is regulated by HIF-1α in CRC patients, and can be used as a potential biomarker and a therapeutic target for CRC.

Crystal structure of the human N-Myc downstream-regulated gene 2 protein provides insight into its role as a tumor suppressor

Considerable attention has recently been paid to the N-Myc downstream-regulated gene (NDRG) family because of its potential as a tumor suppressor in many human cancers. Primary amino acid sequence information suggests that the NDRG family proteins may belong to the α/β-hydrolase (ABH) superfamily; however, their functional role has not yet been determined. Here, we present the crystal structures of the human and mouse NDRG2 proteins determined at 2.0 and 1.7 Å resolution, respectively. Both NDRG2 proteins show remarkable structural similarity to the ABH superfamily, despite limited sequence similarity. Structural analysis suggests that NDRG2 is a nonenzymatic member of the ABH superfamily, because it lacks the catalytic signature residues and has an occluded substrate-binding site. Several conserved structural features suggest NDRG may be involved in molecular interactions. Mutagenesis data based on the structural analysis support a crucial role for helix α6 in the suppression of TCF/β-catenin signaling in the tumorigenesis of human colorectal cancer, via a molecular interaction.

Basic Fibroblast Growth Factor Activates ERK and Induces c-Fos in Human Embryonic Stem Cell Line MizhES1

Human embryonic stem (hES) cells can be maintained in a proliferative undifferentiated state in vitro by growing them on feeder layers of mouse embryonic fibroblast (MEF) cells along with basic fibroblast growth factor (bFGF/FGF-2). To understand the molecular mechanisms involved in the requirement of bFGF in human ES cells, we investigated expression of FGF receptors and intracellular signaling events in response to bFGF in human ES cell line MizhES1. On the basis of the results of RT-PCR, clear expression of FGF receptors FGFR1, FGR2, and FGFR3 was noticed. Because MAPK, PI3K, and PKC pathways are well-known pathways triggered by bFGF in other cells, these pathways were investigated after stimulation with bFGF. bFGF did not induce activation of PI3K or PKC, but induced activation of ERK (extracellular signal-regulated kinase). To monitor the consequences of ERK activation, we examined expression of the immediate early gene c-fos, one downstream target of the MEK1/ERK pathway. mRNA and protein levels of the c-fos gene were increased by bFGF. Induction of c-Fos was dependent on MEKl. Therefore, it is likely that bFGF contributes to maintenance of human ES cells, at least in part, through the MEK1/ERK pathway.

Enhancement of cell survival by stromal cell-derived factor-1/CXCL12 involves activation of CREB and induction of Mcl-1 and c-Fos in factor-dependent human cell line MO7e

Stromal cell-derived factor-1 (SDF-1/CXCL12) enhances the survival of hematopoietic stem and progenitor cells in synergy with other cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF), steel factor, and thrombopoietin (TPO), and both the PI3K/Akt and MAPK pathways have been linked to this survival. To further evaluate intracellular signaling involved in SDF-1/CXCL12 survival effects, we investigated modulation of downstream signaling molecules. The synergistic survival enhancement of SDF-1/CXCL12 plus other cytokines were directly linked to enhanced phosphorylation of p70/85S6K and cAMP responsive element binding protein (CREB), as well as enhanced induction of the Bcl-2 family member Mcl-1. Most prominently, c-Fos, a component of AP1 transcription factor, was synergistically induced by SDF-1/CXCL12 plus other cytokines. These results suggest that SDF-1/CXCL12 enhanced cell survival in synergy with other cytokines involves activation of CREB and induction of Mcl-1 and c-Fos.

Cloning of the human cDNA sequence encoding the NADH:ubiquinone oxidoreductase MLRQ subunit

A cDNA clone encoding human NADH:ubiquinone oxidoreductase (complex I of mitochondrial respiratory chain) MLRQ subunit was isolated from human fetal liver cDNA library. The clone contained an open reading frame of 246 by which predicted a protein comprising 81 amino acids with a calculated molecular weight of 9,370 Da. The deduced amino acid sequence exhibited 95% homology (88% identity and 7% favored substitution) to that of bovine MLRQ subunit. Northern analysis revealed that the cDNA clone hybridized with a 0.7 kb mRNA species which was present in all tissues examined. The expression level of the 0.7 kb mRNA in heart, skeletal muscle, and brain was higher than in other organs. Human MLRQ cDNA could cross-hybridize with the genomic DNAs from various species.

Cloning and expression of human cDNA encoding Na+, K(+)-ATPase gamma-subunit

A cDNA clone encoding the Na+, K(+)-Atpase gamma-subunit polypeptide was cloned from a human fetal liver cDNA library. The deduced amino acid sequence of the protein comprised 58 amino acids with a calculated molecular weight of 6400 Da, and showed about 86% homology when compared with those of the bovine, rat and mouse Na+, K(+)-ATPase gamma-subunits published elsewhere. Northern blot analysis showed that the cDNA hybridized to a 0.7 kb mRNA which was expressed in human kidney, pancreas and fetal liver.

Cloning and characterization of cDNA for human adenylate kinase 2A

We have isolated and characterized a cDNA clone encoding human adenylate kinase 2A (AK2A) from cDNA libraries of fetal liver origin. The complete nucleotide sequence of the cloned 889 nucleotide cDNA fragment indicated that the deduced gene product of human AK2A is composed of 239 amino acids with a molecular weight of 26 kD. Comparison of these nucleotide and amino acid sequences with the corresponding sequences of bovine AK2A and rat AK2 revealed a high degree of conservation. It showed 91% and 98% homologies in DNA and amino acid sequences, respectively, with bovine AK2A throughout the full open reading frame. RNA blot analysis revealed that three species of mRNA were present with approximate sizes of 3.4, 2.1, and 1.0 kb. This gene was expressed in E. coli cells and the recombinant protein was enzymatically active.