Properties of Type Iax Supernova 2019muj in the Late Phase: Existence, Nature and Origin of the Iron-rich Dense Core

Type Iax Supernovae (SNe Iax) form a class of peculiar SNe Ia, whose early-phase spectra share main spectral line identifications with canonical SNe Ia but with higher ionization and much lower line velocities. Their late-time behaviors deviate from usual SNe Ia in many respects; SNe Iax keep showing photospheric spectra over several 100 days and the luminosity decline is very slow. In the present work, we study the late-time spectra of SN Iax 2019muj including a newly-presented spectrum at ~500 days. The spectrum is still dominated by allowed transitions but with lower ionization state, with possible detection of [O I]6300, 6363. By comprehensively examining the spectral formation processes of allowed transitions (Fe II, Fe I, and the Ca II NIR triplet) and forbidden transitions ([Ca II]7292, 7324 and the [O I]), we quantitatively constrain the nature of the innermost region and find that it is distinct from the outer ejecta; the mass of the innermost component is ~0.03 Msun dominated by Fe (which can be initially 56Ni), expanding with the velocity of ~760 km/s. We argue that the nature of the inner component is explained by the failed/weak white-dwarf thermonuclear explosion scenario. We suggest that a fraction of the 56Ni-rich materials initially confined in (the envelope of) the bound remnant can later be ejected by the energy input through the 56Ni/Co/Fe decay, forming the `second' unbound ejecta component which manifests itself as the inner dense component seen in the late phase.Comment: 35 pages, 18 figures. Accepted for publication in Ap

Systematic Investigation of Very Early-Phase Spectra of Type Ia Supernovae

It has been widely accepted that Type Ia supernovae (SNe Ia) are thermonuclear explosions of a CO white dwarf. However, the natures of the progenitor system(s) and explosion mechanism(s) are still unclarified. Thanks to the recent development of transient observations, they are now frequently discovered shortly after the explosion, followed by rapid spectroscopic observations. In this study, by modeling very early-phase spectra of SNe Ia, we try to constrain the explosion models of SNe Ia. By using the Monte Carlo radiation transfer code, TARDIS, we estimate the properties of their outermost ejecta. We find that the photospheric velocity of normal-velocity supernovae (NV SNe) in the first week is $\sim$15000 km s$^{-1}$. The outer velocity, to which the carbon burning extends, spans the range between $\sim$20000 and 25000 km s$^{-1}$. The ejecta density of NV SNe also shows a large diversity. For high-velocity supernovae (HV SNe) and 1999aa-like SNe, the photospheric velocity is higher, $\sim$20000 km s$^{-1}$. They are different in the photospheric density, with HV SNe having higher density than 1999aa-like SNe. For all these types, we show that the outermost composition is closely related to the outermost ejecta density; the carbon burning layer and the unburnt carbon layer are found in the higher-density and lower-density objects, respectively. This finding suggests that there might be two sequences, the high-density and carbon-poor group (HV SNe and some NV SNe) and the low-density and carbon-rich group (1999aa-like and other NV SNe), which may be associated with different progenitor channels.Comment: 22 pages, 11 figures, and 6 tables. Accepted for publication in Ap

Phenethyl iosothiocyanate activates leptin signaling

Obesity, a principal risk factor for the development of diabetes mellitus, heart disease, and hypertension, is a growing and serious health problem all over the world. Leptin is a weight-reducing hormone produced by adipose tissue, which decreases food intake via hypothalamic leptin receptors (Ob-Rb) and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway. Protein tyrosine phosphatase 1B (PTP1B) negatively regulates leptin signaling by dephosphorylating JAK2, and the increased activity of PTP1B is implicated in the pathogenesis of obesity. Hence, inhibition of PTP1B may help prevent and reduce obesity. In this study, we revealed that phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate in certain cruciferous vegetables, potently inhibits recombinant PTP1B by binding to the reactive cysteinyl thiol. Moreover, we found that PEITC causes the ligand-independent phosphorylation of Ob-Rb, JAK2, and STAT3 by inhibiting cellular PTP1B in differentiated human SH-SY5Y neuronal cells. PEITC treatment also induced nuclear accumulation of phosphorylated STAT3, resulting in enhanced anorexigenic POMC expression and suppressed orexigenic NPY/AGRP expression. We demonstrated that oral administration of PEITC to mice significantly reduces food intake, and stimulates hypothalamic leptin signaling. Our results suggest that PEITC might help prevent and improve obesity

Loss of Parp-1 affects gene expression profile in a genome-wide manner in ES cells and liver cells

BACKGROUND: Many lines of evidence suggest that poly(ADP-ribose) polymerase-1 (Parp-1) is involved in transcriptional regulation of various genes as a coactivator or a corepressor by modulating chromatin structure. However, the impact of Parp-1-deficiency on the regulation of genome-wide gene expression has not been fully studied yet. RESULTS: We employed a microarray analysis covering 12,488 genes and ESTs using mouse Parp-1-deficient (Parp-1(-/-)) embryonic stem (ES) cell lines and the livers of Parp-1(-/- )mice and their wild-type (Parp-1(+/+)) counterparts. Here, we demonstrate that of the 9,907 genes analyzed, in Parp-1(-/- )ES cells, 9.6% showed altered gene expression. Of these, 6.3% and 3.3% of the genes were down- or up-regulated by 2-fold or greater, respectively, compared with Parp-1(+/+ )ES cells (p < 0.05). In the livers of Parp-1(-/- )mice, of the 12,353 genes that were analyzed, 2.0% or 1.3% were down- and up-regulated, respectively (p < 0.05). Notably, the number of down-regulated genes was higher in both ES cells and livers, than that of the up-regulated genes. The genes that showed altered expression in ES cells or in the livers are ascribed to various cellular processes, including metabolism, signal transduction, cell cycle control and transcription. We also observed expression of the genes involved in the pathway of extraembryonic tissue development is augmented in Parp-1(-/- )ES cells, including H19. After withdrawal of leukemia inhibitory factor, expression of H19 as well as other trophoblast marker genes were further up-regulated in Parp-1(-/- )ES cells compared to Parp-1(+/+ )ES cells. CONCLUSION: These results suggest that Parp-1 is required to maintain transcriptional regulation of a wide variety of genes on a genome-wide scale. The gene expression profiles in Parp-1-deficient cells may be useful to delineate the functional role of Parp-1 in epigenetic regulation of the genomes involved in various biological phenomena

Transcriptome profiling of spinal muscular atrophy motor neurons derived from mouse embryonic stem cells.

Proximal spinal muscular atrophy (SMA) is an early onset, autosomal recessive motor neuron disease caused by loss of or mutation in SMN1 (survival motor neuron 1). Despite understanding the genetic basis underlying this disease, it is still not known why motor neurons (MNs) are selectively affected by the loss of the ubiquitously expressed SMN protein. Using a mouse embryonic stem cell (mESC) model for severe SMA, the RNA transcript profiles (transcriptomes) between control and severe SMA (SMN2+/+;mSmn-/-) mESC-derived MNs were compared in this study using massively parallel RNA sequencing (RNA-Seq). The MN differentiation efficiencies between control and severe SMA mESCs were similar. RNA-Seq analysis identified 3,094 upregulated and 6,964 downregulated transcripts in SMA mESC-derived MNs when compared against control cells. Pathway and network analysis of the differentially expressed RNA transcripts showed that pluripotency and cell proliferation transcripts were significantly increased in SMA MNs while transcripts related to neuronal development and activity were reduced. The differential expression of selected transcripts such as Crabp1, Crabp2 and Nkx2.2 was validated in a second mESC model for SMA as well as in the spinal cords of low copy SMN2 severe SMA mice. Furthermore, the levels of these selected transcripts were restored in high copy SMN2 rescue mouse spinal cords when compared against low copy SMN2 severe SMA mice. These findings suggest that SMN deficiency affects processes critical for normal development and maintenance of MNs

Induction of IL-17 production from human peripheral blood CD4+ cells by asbestos exposure

We have previously reported that chronic, recurrent and low-dose exposure to asbestos fibers causes a reduction in antitumor immunity. Investigation of natural killer (NK) cells using an in vitro cell line model and comprising in vitro activation using freshly isolated NK cells co-cultured with chrysotile fibers, as well as NK cells derived from asbestos-exposed patients with pleural plaque (PP) or malignant mesothelioma (MM), revealed decreased expression of NK cell activating receptors such as NKG2D, 2B4 and NKp46. An in vitro differentiation and clonal expansion model for CD8+ cytotoxic T lymphocytes (CTLs) showed reduced cytotoxicity with decreased levels of cytotoxic molecules such as granzyme B and perforin, as well as suppressed proliferation of CTLs. Additionally, analysis of T helper cells showed that surface CXCR3, chemokine receptor, and the productive potential of interferon (IFN)γ were reduced following asbestos exposure in an in vitro cell line model and in peripheral CD4+ cells of asbestos-exposed patients. Moreover, experiments revealed that asbestos exposure enhanced regulatory T cell (Treg) function. This study also focused on CXCR3 expression and the Th-17 cell fraction. Following activation with T-cell receptor and co-culture with various concentrations of chrysotile fibers using freshly isolated CD4+ surface CXCR3 positive and negative fractions, the intracellular expression of CXCR3, IFNγ and IL-17 remained unchanged when co-cultured with chrysotile. However, subsequent re-stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin resulted in enhanced IL-17 production and expression, particularly in CD4+ surface CXCR3 positive cells. These results indicated that the balance and polarization between Treg and Th-17 fractions play an important role with respect to the immunological effects of asbestos and the associated reduction in antitumor immunity

Induction of IL-17 production from human peripheral blood CD4+ cells by asbestos exposure

We have previously reported that chronic, recurrent and low-dose exposure to asbestos fibers causes a reduction in antitumor immunity. Investigation of natural killer (NK) cells using an in vitro cell line model and comprising in vitro activation using freshly isolated NK cells co-cultured with chrysotile fibers, as well as NK cells derived from asbestos-exposed patients with pleural plaque (PP) or malignant mesothelioma (MM), revealed decreased expression of NK cell activating receptors such as NKG2D, 2B4 and NKp46. An in vitro differentiation and clonal expansion model for CD8+ cytotoxic T lymphocytes (CTLs) showed reduced cytotoxicity with decreased levels of cytotoxic molecules such as granzyme B and perforin, as well as suppressed proliferation of CTLs. Additionally, analysis of T helper cells showed that surface CXCR3, chemokine receptor, and the productive potential of interferon (IFN)γ were reduced following asbestos exposure in an in vitro cell line model and in peripheral CD4+ cells of asbestos-exposed patients. Moreover, experiments revealed that asbestos exposure enhanced regulatory T cell (Treg) function. This study also focused on CXCR3 expression and the Th-17 cell fraction. Following activation with T-cell receptor and co-culture with various concentrations of chrysotile fibers using freshly isolated CD4+ surface CXCR3 positive and negative fractions, the intracellular expression of CXCR3, IFNγ and IL-17 remained unchanged when co-cultured with chrysotile. However, subsequent re-stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin resulted in enhanced IL-17 production and expression, particularly in CD4+ surface CXCR3 positive cells. These results indicated that the balance and polarization between Treg and Th-17 fractions play an important role with respect to the immunological effects of asbestos and the associated reduction in antitumor immunity