Paclitaxel Modulates TGFβ Signaling in Scleroderma Skin Grafts in Immunodeficient Mice

BACKGROUND: Systemic sclerosis (SSc) is characterized by excessive fibrosis and obliterative vascular lesions. Abnormal TGFβ activation is implicated in the pathogenesis of SSc. Aberrant TGFβ/Smad signaling can be controlled by stabilization of microtubules with paclitaxel. METHODS AND FINDINGS: SSc and healthy human skin biopsies were incubated in the presence or absence of paclitaxel followed by transplantation into severe combined immunodeficient mice. TGFβ signaling, fibrosis, and neovessel formation were evaluated by quantitative RT-PCR and immunohistochemical staining. Paclitaxel markedly suppressed Smad2 and Smad3 phosphorylation and collagen deposition in SSc grafts. As a result, the autonomous maintenance/reconstitution of the SSc phenotype was prevented. Remarkably, SSc grafts showed a 2-fold increase in neovessel formation relative to normal grafts, regardless of paclitaxel treatment. Angiogenesis in SSc grafts was associated with a substantial increase in mouse PECAM-1 expression, indicating the mouse origin of the neovascular cells. CONCLUSION: Low-dose paclitaxel can significantly suppress TGFβ/Smad activity and lessen fibrosis in SCID mice. Transplantation of SSc skin into SCID mice elicits a strong angiogenesis—an effect not affected by paclitaxel. Although prolonged chemotherapy with paclitaxel at higher doses is associated with pro-fibrotic and anti-angiogenic changes, the findings described here indicate that low-dose paclitaxel may have therapeutic benefits for SSc via modulating TGFβ signaling

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Prevalence of genetic polymorphisms in atopic families

Genetic susceptibility to atopy and asthma is due to multiple genes interacting with each other and with environment factors. Variants in regulatory or coding regions of specific genes have been associated with atopy and asthma. Polymorphisms at position -308 in the promoter region of the TNFα gene, -590 in the promoter region of the IL4 gene and amino acid position 237 of the FceRiβ gene have been reported with increased frequency in asthmatic as opposed to control subjects. The aim of this thesis was to determine the predictive value of these polymorphisms in the development of childhood atopy and asthma and whether any of these polymorphisms were associated with atopy and asthma in adult subjects. A prospective cohort including 493 infants born into atopic families was selected. Cord blood was collected at birth. Each infant was assessed at 12 months for respiratory symptoms and skin prick tests for 14 common allergens were performed. DNA was extracted for infants and their parents. Polymerase chain reaction based techniques were used to genotype all the infants and their parents for TNFα-308, IL4-590 and FceRip polymorphisms. In whites, there was a significant association of the IL4-590 polymorphism with "probable asthma"; there were no association of the TNFα-308 and FceRiβ polymorphisms with asthma or atopy in either the parents or their children. Therefore, IL4-590 polymorphism may be a risk factor for the development of asthma while TNFα-308 and FceRiβ polymorphisms had no predictive value for atopic diseases in whites. In the whole infant population, we found the allele frequency of the IL4-590 polymorphism was significantly higher than that in the non-atopic, non-asthmatic controls (p=0.04) or in the general population (p=0.01). The prevalence of atopy was significantly higher in infants with the T allele of IL4-590 polymorphism (IL4-590*T) than in those without this allele (p=0.002). The allele frequency of IL4-590*T was significantly higher in Orientals than that in whites (p<0.0001). To avoid a false positive association caused by population admixture, the transmission/disequilibrium test was performed. A borderline association of IL4-590*T with atopy (p=0.07) was detected. This adds power to our suggestion that IL4-590*T may play a role in the pathogenesis of atopy.Medicine, Faculty ofMedicine, Department ofExperimental Medicine, Division ofGraduat

Transforming growth factor-beta-induced inhibition of myogenesis is mediated through Smad pathway and is modulated by microtubule dynamic stability

The expression of muscle-specific genes associated with myogenesis is controlled by several myogenic transcription factors, including myogenin and MEF2D. Transforming growth factor-beta (TGF-beta) has been shown to inhibit myogenesis, yet the molecular mechanisms underlying such inhibition are not known. In the present study, TGF-beta was shown to inhibit myogenin and MEF2D expression and myotube formation in C2C12 myoblasts cultured in differentiation medium in a cell density-dependent manner. Transfection of C2C12 cells with Smad7, an antagonist for TGF-beta/Smad signaling, restored the capacity of these cells to differentiate in the presence of TGF-beta or when cultured in growth medium at low confluence, conditions that hinder muscle differentiation. Moreover, nocodazole, a microtubule-destabilizing agent, enhanced the inhibition of myogenesis exerted by TGF-beta, an effect that could be restored by tubulin-polymerizing agent taxol, both of which have been shown to affect Smad-microtubule interaction and regulate TGF-beta/Smad signaling. Our results indicate that TGF-beta inhibits myogenesis, at least in part, via Smad pathway, and provide evidence that low-dose pharmacological agents taxol and nocodazole can be used as a means to modulate myogenesis without affecting cell survival

Aging in the Atherosclerosis Milieu May Accelerate the Consumption of Bone Marrow Endothelial Progenitor Cells

OBJECTIVE—We have demonstrated that bone marrow cells from young and wild-type (WT), but not old apoE, mice are capable of preventing atherosclerosis. This study was performed to elucidate the numerical and functional changes underlying the efficacy difference between young and old bone marrow. METHODS AND RESULTS—CD34/VEGFR2 conventional endothelial progenitor cells and lin/cKit/Sca-1 hematopoietic stem cells did not differ numerically or functionally between young and old apoE bone marrow. Fluorescence- activated cell sorter analysis, however, showed that a group of cells (simple little cells or SLCs), characteristically located in the lower left quadrant of forward scatter/side scatter flow cytometric plot, were markedly decreased in old WT and apoE marrow, but abundantly present in young WT and apoE bone marrow. The SLC fraction was mainly composed of lin/cKit/Sca-1 cells. In vitro differentiation assay demonstrated substantially more efficient endothelial differentiation of lin/cKit/Sca-1 SLCs than other bone marrow fractions at a single cell level and en masse. Furthermore, old lin/cKit/Sca-1 SLCs had a trend of decreased endothelial differentiation capability. CONCLUSIONS—Lin/cKit/Sca-1 SLCs may represent a previously unrecognized cell population, enriched for endothelial progenitors. The identification of these cells may help improve the efficacy of cell therapy

Upregulation of PAI-1 is mediated through TGF-beta/Smad pathway in transplant arteriopathy

Plasminogen activator inhibitor type 1 (PAI-1) is the primary physiologic inhibitor of plasminogen activator in vivo. Increased PAI-1 expression is associated with arteriosclerosis. Transforming growth factor-beta (TGF-beta) induces PAI-1 production via Smads. In vivo, TGF-beta receptors (TbetaRs), Smad2, Smad3, and Smad4, PAI-1, and Smad2 phosphorylation were examined by immunohistochemistry in 3 native aortas, 14 rat aortic syngrafts, and 19 allografts collected at 15, 30, and 45 days post-transplantation. In vitro, phosphorylation of Smad2 and induction of PAI-1 mRNA in human aortic smooth muscle cells (SMCs) in response to TGF-beta treatment were detected by Western blot and by TaqMan real-time RT-PCR, respectively. Immunohistochemical staining revealed that vascular parenchymal cells contained TbetaRI, TbetaRII, Smad2, Smad3, and Smad4, known signaling transducers for TGF-beta/Smad pathway, in all samples. Intense staining for phospho-Smad2 was observed in 94% of endothelial cells (ECs), 86% of intimal cells, 27% of medial SMCs, and 38% of adventitial cells at all 3 time points in all aortic allografts, but only in 5% of ECs in syngrafts. PAI-1 immunoreactivity was detected in similar number of cells, and from consecutive sections, phospho-Smad2 colocalized with PAI-1, in the aortic allografts. Low basal level PAI-1 expression was observed in aortic syngrafts and native vessels. Smad2 phosphorylation and time-dependent PAI-1 induction were detected in cultured SMCs upon TGF-beta treatment. Phospho-Smad2 staining in aortic allografts indicates the activation of TGF-beta signaling in allo-transplantation; and co-localization of PAI-1 and phospho-Smad2 suggests that PAI-1 upregulation is mediated mainly by TGF-beta/Smad pathway in aortic allografts

A crucial role for GRK2 in regulation of endothelial cell nitric oxide synthase function in portal hypertension

Nitric oxide (NO) production by endothelial cell nitric oxide synthase (eNOS) in sinusoidal endothelial cells is reduced in the injured liver and leads to intrahepatic portal hypertension. We sought to understand the mechanism underlying defective eNOS function. Phosphorylation of the serine-threonine kinase Akt, which activates eNOS, was substantially reduced in sinusoidal endothelial cells from injured livers. Overexpression of Akt in vivo restored phosphorylation of Akt and production of NO and reduced portal pressure in portal hypertensive rats. We found that Akt physically interacts with G-protein-coupled receptor kinase-2 (GRK2), and that this interaction inhibits Akt activity. Furthermore, GRK2 expression increased in sinusoidal endothelial cells from portal hypertensive rats and knockdown of GRK2 restored Akt phosphorylation and NO production, and normalized portal pressure. Finally, after liver injury, GRK2-deficient mice developed less severe portal hypertension than control mice. Thus, an important mechanism underlying impaired activity of eNOS in injured sinusoidal endothelial cells is defective phosphorylation of Akt caused by overexpression of GRK2 after injury