Beta-1,4-galactosyltransferase-3 deficiency suppresses the growth of immunogenic tumors in mice.

Background: Beta-1,4-galactosyltransferase-3 (B4GALT3) belongs to the family of beta-1,4-galactosyltransferases (B4GALTs) and is responsible for the transfer of UDP-galactose to terminal -acetylglucosamine. B4GALT3 is differentially expressed in tumors and adjacent normal tissues, and is correlated with clinical prognosis in several cancers, including neuroblastoma, cervical cancer, and bladder cancer. However, the exact role of B4GALT3 in the tumor immune microenvironment (TIME) remains unclear.

A degron system targeting endogenous PD-1 inhibits the growth of tumor cells in mice.

Recently, targeted protein degradation systems have been developed using the ubiquitin-proteasome system. Here, we established Programmed cell death-1 (PD-1) knockdown mice as a model system for subjecting endogenous mouse proteins to the small molecule-assisted shutoff (SMASh) degron system. SMASh degron-tagged PD-1-mCherry in Jurkat cells and CD3 splenocytes were degraded by the NS3/4A protease inhibitors, asunaprevir (ASV) or grazoprevir (GRV).

Heterochromatin protein 1γ deficiency decreases histone H3K27 methylation in mouse neurosphere neuronal genes.

Heterochromatin protein (HP) 1γ, a component of heterochromatin in eukaryotes, is involved in H3K9 methylation. Although HP1γ is expressed strongly in neural tissues and neural stem cells, its functions are unclear. To elucidate the roles of HP1γ, we analyzed HP1γ -deficient (HP1γ KO) mouse embryonic neurospheres and determined that HP1γ KO neurospheres tended to differentiate after quaternary culture.

Galactosyl carbohydrate residues on hematopoietic stem/progenitor cells are essential for homing and engraftment to the bone marrow.

The role of carbohydrate chains in leukocyte migration to inflamed sites during inflammation and trafficking to the lymph nodes under physiological conditions has been extensively characterized. Here, we report that carbohydrate chains also mediate the homing and engraftment of hematopoietic stem/progenitor cells (HSPCs) to the bone marrow (BM). In particular, we found that transplanted BM cells deficient in β-1,4-galactosyltransferase-1 (β4GalT-1) could not support survival in mice exposed to a lethal dose of irradiation.

Lactosylceramide synthases encoded by B4galt5 and 6 genes are pivotal for neuronal generation and myelin formation in mice.

It is uncertain which β4-galactosyltransferase (β4GalT; gene name, B4galt), β4GalT-5 and/or β4GalT-6, is responsible for the production of lactosylceramide (LacCer) synthase, which functions in the initial step of ganglioside biosynthesis. Here, we generated conditional B4galt5 knockout (B4galt5 cKO) mice, using Nestin-Cre mice, and crossed these with B4galt6 KO mice to generate B4galt5 and 6 double KO (DKO) mice in the central nervous system (CNS). LacCer synthase activity and major brain gangliosides were completely absent in brain homogenates from the DKO mice, although LacCer synthase activity was about half its normal level in B4galt5 cKO mice and B4galt6 KO mice.

Cbx3/HP1γ deficiency confers enhanced tumor-killing capacity on CD8 T cells.

Cbx3/HP1γ is a histone reader whose function in the immune system is not completely understood. Here, we demonstrate that in CD8 T cells, Cbx3/HP1γ insufficiency leads to chromatin remodeling accompanied by enhanced Prf1, Gzmb and Ifng expression. In tumors obtained from Cbx3/HP1γ-insufficient mice or wild type mice treated with Cbx3/HP1γ-insufficient CD8 T cells, there is an increase of CD8 effector T cells expressing the stimulatory receptor Klrk1/NKG2D, a decrease in CD4 CD25 FOXP3 regulatory T cells (Treg cells) as well as CD25 CD4 T cells expressing the inhibitory receptor CTLA4.

New insights into the role of Jmjd3 and Utx in axial skeletal formation in mice.

Jmjd3 and Utx are demethylases specific for lysine 27 of histone H3. Previous reports indicate that Jmjd3 is essential for differentiation of various cell types, such as macrophages and epidermal cells in mice, whereas Utx is involved in cancer and developmental diseases in humans and mice, as well as regulation in zebrafish and nematodes. Here, we report that Jmjd3, but not Utx, is involved in axial skeletal formation in mice.

HP-1γ Controls High-Affinity Antibody Response to T-Dependent Antigens.

In vitro observations suggest a role for the mouse heterochromatin protein 1γ (HP-1γ) in the immune system. However, it has not been shown if and how HP-1γ contributes to immunity in vivo. Here we show that in mice, HP-1γ positively regulates the germinal center reaction and high-affinity antibody response to thymus (T)-dependent antigens by limiting the size of CD8(+) regulatory T-cell (Treg) compartment without affecting progenitor B- or T-cell-development.

A replication-dependent passive mechanism modulates DNA demethylation in mouse primordial germ cells.

Germline cells reprogramme extensive epigenetic modifications to ensure the cellular totipotency of subsequent generations and to prevent the accumulation of epimutations. Notably, primordial germ cells (PGCs) erase genome-wide DNA methylation and H3K9 dimethylation marks in a stepwise manner during migration and gonadal periods. In this study, we profiled DNA and histone methylation on transposable elements during PGC development, and examined the role of DNA replication in DNA demethylation in gonadal PGCs.

Evidence that the EphA2 receptor exacerbates ischemic brain injury.

Ephrin (Eph) signaling within the central nervous system is known to modulate axon guidance, synaptic plasticity, and to promote long-term potentiation. We investigated the potential involvement of EphA2 receptors in ischemic stroke-induced brain inflammation in a mouse model of focal stroke. Cerebral ischemia was induced in male C57Bl6/J wild-type (WT) and EphA2-deficient (EphA2(-/-)) mice by middle cerebral artery occlusion (MCAO; 60 min), followed by reperfusion (24 or 72 h).

HP1γ links histone methylation marks to meiotic synapsis in mice.

During meiosis, specific histone modifications at pericentric heterochromatin (PCH), especially histone H3 tri- and dimethylation at lysine 9 (H3K9me3 and H3K9me2, respectively), are required for proper chromosome interactions. However, the molecular mechanism by which H3K9 methylation mediates the synapsis is not yet understood. We have generated a Cbx3-deficient mouse line and performed comparative analysis on Suv39h1/h2-, G9a- and Cbx3-deficient spermatocytes.

Loss of heterochromatin protein 1 gamma reduces the number of primordial germ cells via impaired cell cycle progression in mice.

Signals from extraembryonic tissues in mice determine which proximal epiblast cells become primordial germ cells (PGCs). After their specification, approximately 40 PGCs appear at the base of the allantoic bud and migrate to the genital ridges, where they expand to about 25 000 cells by Embryonic Day (E)13.5.

Beta4-galactosyltransferase-5 is a lactosylceramide synthase essential for mouse extra-embryonic development.

Glycosphingolipids (GSLs) are important for various biological functions in the nervous system, the immune system, embryogenesis and in other tissues and processes. Lactosylceramide (LacCer), which is synthesized from glucosylceramide (GlcCer) by LacCer synthase, is a core structure of GSLs, including gangliosides. LacCer synthase was reported to be synthesized by the beta4-galactosyltransferase-6 (beta4GalT-6) gene in the rat brain.

Bidirectional signaling through ephrinA2-EphA2 enhances osteoclastogenesis and suppresses osteoblastogenesis.

Bone is remodeled constantly throughout life by bone-resorbing osteoclasts and bone-forming osteoblasts. To maintain bone volume and quality, differentiation of osteoclasts and osteoblasts is tightly regulated through communication between and within these two cell lineages. Previously we reported that cell-cell interaction mediated by ephrinB2 ligand on osteoclasts and EphB4 receptor on osteoblasts generates bidirectional anti-osteoclastogenic and pro-osteoblastogenic signals into respective cells and presumably facilitates transition from bone resorption to bone formation.

EphA2 is an essential mediator of UV radiation-induced apoptosis.

One of the physiologic consequences of excessive UV radiation (UVR) exposure is apoptosis. This critical response serves to eliminate genetically injured cells and arises, in part, from activation of DNA damage and p53 signaling. Other contributory pathways, however, likely exist but have not been fully characterized.

Wtap is required for differentiation of endoderm and mesoderm in the mouse embryo.

Wilms' tumor 1-associating protein (WTAP) was previously identified as a protein associated with Wilms' tumor-1 (WT-1) protein that is essential for the development of the genitourinary system. Although WTAP has been suggested to function in alternative splicing, stabilization of mRNA, and cell growth, its in vivo function is still unclear. We generated Wtap mutant mice using a novel gene-trap approach and showed that Wtap mutant embryos exhibited defective egg-cylinder formation at the gastrulation stage and died by embryonic day 10.

A novel beta-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model.

Mutations in the betaMHC (beta-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the betaMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel betaMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation.

A novel gene trapping for identifying genes expressed under the control of specific transcription factors.

Gene trapping is a powerful method for identifying novel genes and for analyzing their functions. It is, however, difficult to select trapped genes on the basis of their function. To identify genes regulated by transcription factors that are important in the mesodermal formation, we selected trapped ES clones by infection of adenoviral vectors expressing Pax1, Brachyury, and Foxa2.

Development of IgA nephropathy-like disease with high serum IgA levels and increased proportion of polymeric IgA in Beta-1,4-galactosyltransferase-deficient mice.

The glycosylation of glycoproteins is important for their biological activity, conformation and stability. Recent studies indicate that aberrant glycosylation causes various human disorders. Here we report that mice lacking beta-1,4-galactosyltransferase-I (beta4GalT-I), which transfers galactose from UDP-Gal to terminal GlcNAc of N- and O-glycans in a beta-1,4- linkage, developed IgA nephropathy (IgAN)-like disease.

Development of immunoglobulin A nephropathy- like disease in beta-1,4-galactosyltransferase-I-deficient mice.

Beta4 galactosylation of glycoproteins plays important roles in protein conformation, stability, transport, and clearance from the circulation. Recent studies have revealed that aberrant glycosylation causes various human diseases. Here we report that mice lacking beta-1,4-galactosyltransferase (beta4GalT)-I, which transfers galactose to the terminal N-acetylglucosamine of N- and O-linked glycans in a beta-1,4 linkage, spontaneously developed human immunoglobulin A nephropathy (IgAN)-like glomerular lesions with IgA deposition and expanded mesangial matrix.