Lactobacillus helveticus SBT2171 Attenuates Experimental Autoimmune Encephalomyelitis in Mice

We recently reported that Lactobacillus helveticus SBT2171 (LH2171) inhibited the proliferation and inflammatory cytokine production of primary immune cells in vitro, and alleviated collagen-induced arthritis (CIA) in mice, a model of human rheumatoid arthritis (RA). In this study, we newly investigated whether LH2171 could relieve the severity of experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), which is an autoimmune disease, but develop the symptoms by different mechanisms from RA. In MS and EAE, main cause of the disease is the abnormality in CD4+ T cell immunity, whereas in RA and CIA, is that in antibody-mediated immunity. The intraperitoneal administration of LH2171 significantly decreased the incidence and clinical score of EAE in mice. LH2171 also reduced the numbers of pathogenic immune cells, especially Th17 cells, in the spinal cord at the peak stage of disease severity. Interestingly, before the onset of EAE, LH2171 administration remarkably decreased the ratio of Th17 cells to CD4+ T cells in the inguinal lymph nodes (LNs), where pathogenic immune cells are activated to infiltrate the central nervous system, including the spinal cord. Furthermore, the expression of interleukin (IL)-6, an inflammatory cytokine essential for Th17 differentiation, decreased in the LNs of LH2171-administered mice. Moreover, LH2171 significantly inhibited IL-6 production in vitro from both DC2.4 and RAW264.7 cells, model cell lines of antigen-presenting cells. These findings suggest that LH2171 might down-regulate IL-6 production and the subsequent Th17 differentiation and spinal cord infiltration, consequently alleviating EAE symptoms

Manipulating the 3D organization of the largest synthetic yeast chromosome

Whether synthetic genomes can power life has attracted broad interest in the synthetic biology field. Here, we report de novo synthesis of the largest eukaryotic chromosome thus far, synIV, a 1,454,621-bp yeast chromosome resulting from extensive genome streamlining and modification. We developed megachunk assembly combined with a hierarchical integration strategy, which significantly increased the accuracy and flexibility of synthetic chromosome construction. Besides the drastic sequence changes, we further manipulated the 3D structure of synIV to explore spatial gene regulation. Surprisingly, we found few gene expression changes, suggesting that positioning inside the yeast nucleoplasm plays a minor role in gene regulation. Lastly, we tethered synIV to the inner nuclear membrane via its hundreds of loxPsym sites and observed transcriptional repression of the entire chromosome, demonstrating chromosome-wide transcription manipulation without changing the DNA sequences. Our manipulation of the spatial structure of synIV sheds light on higher-order architectural design of the synthetic genomes. </p

Evidence for Sequential and Increasing Activation of Replication Origins along Replication Timing Gradients in the Human Genome

Genome-wide replication timing studies have suggested that mammalian chromosomes consist of megabase-scale domains of coordinated origin firing separated by large originless transition regions. Here, we report a quantitative genome-wide analysis of DNA replication kinetics in several human cell types that contradicts this view. DNA combing in HeLa cells sorted into four temporal compartments of S phase shows that replication origins are spaced at 40 kb intervals and fire as small clusters whose synchrony increases during S phase and that replication fork velocity (mean 0.7 kb/min, maximum 2.0 kb/min) remains constant and narrowly distributed through S phase. However, multi-scale analysis of a genome-wide replication timing profile shows a broad distribution of replication timing gradients with practically no regions larger than 100 kb replicating at less than 2 kb/min. Therefore, HeLa cells lack large regions of unidirectional fork progression. Temporal transition regions are replicated by sequential activation of origins at a rate that increases during S phase and replication timing gradients are set by the delay and the spacing between successive origin firings rather than by the velocity of single forks. Activation of internal origins in a specific temporal transition region is directly demonstrated by DNA combing of the IGH locus in HeLa cells. Analysis of published origin maps in HeLa cells and published replication timing and DNA combing data in several other cell types corroborate these findings, with the interesting exception of embryonic stem cells where regions of unidirectional fork progression seem more abundant. These results can be explained if origins fire independently of each other but under the control of long-range chromatin structure, or if replication forks progressing from early origins stimulate initiation in nearby unreplicated DNA. These findings shed a new light on the replication timing program of mammalian genomes and provide a general model for their replication kinetics

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Increased bone marrow uptake of 18F-FDG in leukemia patients: preliminary findings.

The aim of this retrospective study was to evaluate the characteristics of increased bone marrow uptake of 18F-FDG in patients with leukemia who underwent whole-body 18F-FDG PET/CT. The 18F-FDG PET/CT images of 9 patients with histologically proven leukemia were reviewed. The accumulation of 18F-FDG in the bone marrow was evaluated, and was compared with histological subtype, clinical course, and hematological findings. Nine patients (4 males, 5 females; age range, 5-58 years) had increased bone marrow uptake of 18F-FDG, including 6 patients with acute lymphoblastic leukemia, 1 with acute myeloid leukemia, 1 with chronic myeloid leukemia, and 1 with mature B cell neoplasm. Bone marrow uptake was generally diffuse but focal or inhomogeneous uptake was common, especially in the upper and lower extremities. Patients with increased bone marrow uptake of 18F-FDG commonly complained of fever and bone pain. No correlations between 18F-FDG uptake and peripheral blood findings were observed. Patients with leukemia may have increased bone marrow uptake of 18F-FDG on PET/CT, possibly reflecting leukemic cell activity. Leukemia can be included in the differential diagnosis when increased bone marrow uptake of 18F-FDG is observed

Preventive Effect of Lactobacillus helveticus SBT2171 on Collagen-Induced Arthritis in Mice

We recently reported that the intraperitoneal inoculation of Lactobacillus helveticus SBT2171 inhibited the development of collagen-induced arthritis (CIA), a murine model of rheumatoid arthritis (RA). In the present study, we evaluated the effect of the oral administration of L. helveticus SBT2171 on CIA development and on the regulation of antigen-specific antibody production and inflammatory immune cells, which have been implicated in the development of RA. Both oral administration and intraperitoneal inoculation of L. helveticus SBT2171 reduced joint swelling, body weight loss, and the serum level of bovine type II collagen (CII)-specific antibodies in the CIA mouse model. The intraperitoneal inoculation also decreased the arthritis incidence, joint damage, and serum level of interleukin (IL)-6. In addition, the numbers of total immune cells, total B cells, germinal center B cells, and CD4+ T cells in the draining lymph nodes were decreased following intraperitoneal inoculation of L. helveticus SBT2171. These findings demonstrate the ability of L. helveticus SBT2171 to downregulate the abundance of immune cells and the subsequent production of CII-specific antibodies and IL-6, thereby suppressing the CIA symptoms, indicating its potential for use in the prevention of RA