Genetic variation and phylogenetic analysis of Porcine circovirus type 2 in China from 2016 to 2018

Infection with Porcine circovirus type 2 (PCV2), the essential cause of porcine circovirus (PCV) associated diseases, is a growing problem in swine industry around the world. High nucleotide alteration leads to the constant evolution of PCV2 and outbreak of disease caused by PCV2. In this study, 48 PCV2 strains were isolated in China between 2016 and 2018 and the genetic diversity of these PCV2 isolates was determined. Results showed that these PCV2 isolates were classified into genotypes PCV2a (4 of 48), PCV2b (13 of 48) and PCV2d (31 of 48). Among them, 54.5% isolated in 2016, 65.2% isolated in 2017 and 71.4% isolated in 2018 belonged to PCV2d. It indicated that the prevalence of PCV2d genotype increased. All strains shared 93.4%-100% nucleotide sequence identity for the whole genome. Results of the analysis using RDP 4.0 molecular recombination software showed there were no recombinant events among the 48 PCV2 isolates in this study. Further analysis indicated the presence of higher amino acid residues diversity in important epitopes (43D/G, 115D/G, 134N/T, 165P/T, 169G/R/S, and 210E/G/D) in the predominant genotype PCV2d. Animal tests showed the viral titer of the PCV2d strain LN-3 in sera was higher than that of PCV2b strain HeB-1 at 14 and 21 days post-challenge, however, the differences were not statistically significant. There were also no obvious differences between PCV2d strain LN-3 and PCV2b strain HeB-1 in the amount of PCV2 antigen in lymphoid tissues. On the account of the increasing prevalence of PCV2d genotype, it is necessary to find the cause of PCV2 genotype change, to evaluate the effect of existing commercial vaccines and to develop new vaccines based on PCV2d genotype, if necessary. Keywords: epitope; PCV2d; phylogeny; Porcine circovirus type 2; recombination; genetic diversity.

Association of plasma C-reactive protein with ischaemic stroke: a Mendelian randomization study

BACKGROUND AND PURPOSE

Elevated C-reactive protein (CRP) is associated with an increased risk of ischaemic stroke (IS). However, the causality of this association is uncertain. The aim is to investigate whether genetically raised plasma CRP concentration levels are associated with IS on the basis of the Mendelian randomization method.

METHODS

Based on the National Center for Biotechnology Information single nucleotide polymorphism (SNP) database, the Chinese online genetic database as well as previously published studies, four CRP-associated SNP alleles (rs1130864, rs1205, rs876537 and rs3093059) with minor allele frequency ≥0.15 were selected and the concentration levels of CRP were measured in 378 first-ever IS patients and 613 healthy controls.

RESULTS

Three SNPs were chosen and used as instrumental variables. The adjusted odds ratios (ORs) [95% confidence interval (95% CI)] of IS per addition of the modelled allele were 1.07 (0.79-1.45) for rs876537, 0.99 (0.73-1.35) for rs1205 and 1.08 (0.71-1.65) for rs3093059. The OR (95% CI) of IS for plasma CRP ≥2.0 mg/l was 2.19 (1.06-4.53) compared with <2.0 mg/l. The adjusted OR (95% CI) of IS per genetically predicted 10% higher CRP concentration, based on the three SNPs as the instruments, was 1.02 (0.94-1.11). Furthermore, similar results were obtained with adjusted ORs (95% CI) of 1.00 (0.88-1.13) and 1.04 (0.93-1.16), respectively, for large-artery atherosclerosis and small-artery occlusion per genetically predicted 10% higher CRP concentration.

CONCLUSIONS

This Mendelian randomization study provides no clear support that elevated CRP concentration is causally associated with the risk of IS.

Maintenance of Response With up to 4 Years of Continuous Guselkumab Treatment: Results From the VOYAGE 1 Phase 3 Trial

Abstract not available.

Epigenetic Modifications in Cardiovascular Aging and Diseases

Aging is associated with a progressive decline in cardiovascular structure and function. Accumulating evidence links cardiovascular aging to epigenetic alterations encompassing a complex interplay of DNA methylation, histone posttranslational modifications, and dynamic nucleosome occupancy governed by numerous epigenetic factors. Advances in genomics technology have led to a profound understanding of chromatin reorganization in both cardiovascular aging and diseases. This review summarizes recent discoveries in epigenetic mechanisms involved in cardiovascular aging and diseases and discusses potential therapeutic strategies to retard cardiovascular aging and conquer related diseases through the rejuvenation of epigenetic signatures to a young state.

Stabilizing heterochromatin by DGCR8 alleviates senescence and osteoarthritis

DiGeorge syndrome critical region 8 (DGCR8) is a critical component of the canonical microprocessor complex for microRNA biogenesis. However, the non-canonical functions of DGCR8 have not been studied. Here, we demonstrate that DGCR8 plays an important role in maintaining heterochromatin organization and attenuating aging. An N-terminal-truncated version of DGCR8 (DR8dex2) accelerated senescence in human mesenchymal stem cells (hMSCs) independent of its microRNA-processing activity. Further studies revealed that DGCR8 maintained heterochromatin organization by interacting with the nuclear envelope protein Lamin B1, and heterochromatin-associated proteins, KAP1 and HP1γ. Overexpression of any of these proteins, including DGCR8, reversed premature senescent phenotypes in DR8dex2 hMSCs. Finally, DGCR8 was downregulated in pathologically and naturally aged hMSCs, whereas DGCR8 overexpression alleviated hMSC aging and mouse osteoarthritis. Taken together, these analyses uncovered a novel, microRNA processing-independent role in maintaining heterochromatin organization and attenuating senescence by DGCR8, thus representing a new therapeutic target for alleviating human aging-related disorders.

Mitofusin 2 Is Essential for IP3-Mediated SR/Mitochondria Metabolic Feedback in Ventricular Myocytes

Aim: Endothelin-1 (ET-1) and angiotensin II (Ang II) are multifunctional peptide hormones that regulate the function of the cardiovascular and renal systems. Both hormones increase the intracellular production of inositol-1,4,5-trisphosphate (IP₃) by activating their membrane-bound receptors. We have previously demonstrated that IP₃-mediated sarcoplasmic reticulum (SR) Ca²⁺ release results in mitochondrial Ca²⁺ uptake and activation of ATP production. In this study, we tested the hypothesis that intact SR/mitochondria microdomains are required for metabolic IP₃-mediated SR/mitochondrial feedback in ventricular myocytes.

Methods: As a model for disrupted mitochondrial/SR microdomains, cardio-specific tamoxifen-inducible mitofusin 2 (Mfn2) knock out (KO) mice were used. Mitochondrial Ca²⁺ uptake, membrane potential, redox state, and ATP generation were monitored in freshly isolated ventricular myocytes from Mfn2 KO mice and their control wild-type (WT) littermates.

Results: Stimulation of ET-1 receptors in healthy control myocytes increases mitochondrial Ca²⁺ uptake, maintains mitochondrial membrane potential and redox balance leading to the enhanced ATP generation. Mitochondrial Ca²⁺ uptake upon ET-1 stimulation was significantly higher in interfibrillar (IFM) and perinuclear (PNM) mitochondria compared to subsarcolemmal mitochondria (SSM) in WT myocytes. Mfn2 KO completely abolished mitochondrial Ca²⁺ uptake in IFM and PNM mitochondria but not in SSM. However, mitochondrial Ca²⁺ uptake induced by beta-adrenergic receptors activation with isoproterenol (ISO) was highest in SSM, intermediate in IFM, and smallest in PNM regions. Furthermore, Mfn2 KO did not affect ISO-induced mitochondrial Ca²⁺ uptake in SSM and IFM mitochondria; however, enhanced mitochondrial Ca²⁺ uptake in PNM. In contrast to ET-1, ISO induced a decrease in ATP levels in WT myocytes. Mfn2 KO abolished ATP generation upon ET-1 stimulation but increased ATP levels upon ISO application with highest levels observed in PNM regions.

Conclusion: When the physical link between SR and mitochondria by Mfn2 was disrupted, the SR/mitochondrial metabolic feedback mechanism was impaired resulting in the inability of the IP₃-mediated SR Ca²⁺ release to induce ATP production in ventricular myocytes from Mfn2 KO mice. Furthermore, we revealed the difference in Mfn2-mediated SR-mitochondrial communication depending on mitochondrial location and type of communication (IP₃R-mRyR1 vs. ryanodine receptor type 2-mitochondrial calcium uniporter).

Spin fluctuation induced Weyl semimetal state in the paramagnetic phase of EuCd2As2

Weyl fermions as emergent quasiparticles can arise in Weyl semimetals (WSMs) in which the energy bands are nondegenerate, resulting from inversion or time-reversal symmetry breaking. Nevertheless, experimental evidence for magnetically induced WSMs is scarce. Here, using photoemission spectroscopy, we observe that the degeneracy of Bloch bands is already lifted in the paramagnetic phase of EuCd2As2. We attribute this effect to the itinerant electrons experiencing quasi-static and quasi-long-range ferromagnetic fluctuations. Moreover, the spin-nondegenerate band structure harbors a pair of ideal Weyl nodes near the Fermi level. Hence, we show that long-range magnetic order and the spontaneous breaking of time-reversal symmetry are not essential requirements for WSM states in centrosymmetric systems and that WSM states can emerge in a wider range of condensed matter systems than previously thought.

Use of dose-exposure-response relationships in Phase 2 and Phase 3 guselkumab studies to optimize dose selection in psoriasis

BACKGROUND

Guselkumab is an anti-interleukin-23 monoclonal antibody for the treatment of moderate-to-severe psoriasis.

OBJECTIVE

To evaluate the association between dose-response and exposure-response of guselkumab in Phase 2 and Phase 3 studies to optimize dose selection.

METHODS

Serum guselkumab concentrations in Phase 2 and Phase 3 studies (VOYAGE 1 and VOYAGE 2) were measured using a validated immunoassay. Efficacy assessments included Physician's Global Assessment (PGA), Investigator's Global Assessment (IGA) and Psoriasis Area and Severity Index (PASI).

RESULTS

In Phase 2, a positive dose-response relationship was observed for PASI and PGA (5-mg through 100-mg dose regimens). Exposure-response analysis showed that patients with steady-state trough serum guselkumab concentrations ≥0.67 μg/mL achieved the highest levels of efficacy (PGA 0/1: 90.0%; PGA 0: 70.0%). The guselkumab 100-mg every 8-week (q8w) dose regimen, safe and well-tolerated in Phase 2, provided the highest serum guselkumab concentrations among all regimens studied and was selected for Phase 3. In Phase 3, 72.5% of patients achieved guselkumab concentrations ≥0.67 μg/mL at week 28, the level associated with the highest clinical responses in Phase 2, with patients achieving response rates of IGA 0/1: 91.2%, IGA 0: 55.3%, PASI 90: 83.8% and PASI 100: 49.1% at week 28.

CONCLUSION

The 100-mg guselkumab q8w dose regimen, based on the dose-exposure-response relationship from the Phase 2 study, produced the target serum concentration associated with high-level efficacy in the majority of patients in Phase 3. Phase 3 data further confirmed that guselkumab 100mg q8w is the optimum dosing regimen for treating patients with moderate-to-severe psoriasis.

Chemical screen identifies a geroprotective role of quercetin in premature aging

Aging increases the risk of various diseases. The main goal of aging research is to find therapies that attenuate aging and alleviate aging-related diseases. In this study, we screened a natural product library for geroprotective compounds using Werner syndrome (WS) human mesenchymal stem cells (hMSCs), a premature aging model that we recently established. Ten candidate compounds were identified and quercetin was investigated in detail due to its leading effects. Mechanistic studies revealed that quercetin alleviated senescence via the enhancement of cell proliferation and restoration of heterochromatin architecture in WS hMSCs. RNA-sequencing analysis revealed the transcriptional commonalities and differences in the geroprotective effects by quercetin and Vitamin C. Besides WS hMSCs, quercetin also attenuated cellular senescence in Hutchinson-Gilford progeria syndrome (HGPS) and physiological-aging hMSCs. Taken together, our study identifies quercetin as a geroprotective agent against accelerated and natural aging in hMSCs, providing a potential therapeutic intervention for treating age-associated disorders.

Up-regulation of FOXD1 by YAP alleviates senescence and osteoarthritis

Cellular senescence is a driver of various aging-associated disorders, including osteoarthritis. Here, we identified a critical role for Yes-associated protein (YAP), a major effector of Hippo signaling, in maintaining a younger state of human mesenchymal stem cells (hMSCs) and ameliorating osteoarthritis in mice. Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR associated protein 9 nuclease (Cas9)-mediated knockout (KO) of YAP in hMSCs resulted in premature cellular senescence. Mechanistically, YAP cooperated with TEA domain transcriptional factor (TEAD) to activate the expression of forkhead box D1 (FOXD1), a geroprotective protein. YAP deficiency led to the down-regulation of FOXD1. In turn, overexpression of YAP or FOXD1 rejuvenated aged hMSCs. Moreover, intra-articular administration of lentiviral vector encoding YAP or FOXD1 attenuated the development of osteoarthritis in mice. Collectively, our findings reveal YAP–FOXD1, a novel aging-associated regulatory axis, as a potential target for gene therapy to alleviate osteoarthritis.

The Hippo signalling effector YAP and the transcription factor FOXD1 play a role in alleviating cellular senescence and osteoarthritis, identifying the YAP-FOXD1 axis as a potential therapeutic target for aging-associated disorders.

Stem cell aging contributes to aging-associated degenerative diseases. Studies aiming to characterize the mechanisms of stem cell aging are critical for obtaining a comprehensive understanding of the aging process and developing novel strategies to treat aging-related diseases. As a prevalent aging-associated chronic joint disorder, osteoarthritis is a leading cause of disability. Senescent mesenchymal stem cells (MSCs) residing in the joint may be a critical target for the prevention of osteoarthritis; however, the key regulators of MSC senescence are little known, and targeting aging regulatory genes for the treatment of osteoarthritis has not yet been reported. Here, we show that Yes-associated protein (YAP), a major effector of Hippo signaling, represses human mesenchymal stem cell (hMSC) senescence through transcriptional up-regulation of forkhead box D1 (FOXD1). Lentiviral gene transfer of YAP or FOXD1 can rejuvenate aged hMSCs and ameliorate osteoarthritis symptoms in mouse models. We propose that the YAP–FOXD1 axis is a novel target for combating aging-associated diseases.

Modeling CADASIL vascular pathologies with patient-derived induced pluripotent stem cells

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary cerebrovascular disease caused by a NOTCH3 mutation. However, the underlying cellular and molecular mechanisms remain unidentified. Here, we generated non-integrative induced pluripotent stem cells (iPSCs) from fibroblasts of a CADASIL patient harboring a heterozygous NOTCH3 mutation (c.3226C>T, p.R1076C). Vascular smooth muscle cells (VSMCs) differentiated from CADASIL-specific iPSCs showed gene expression changes associated with disease phenotypes, including activation of the NOTCH and NF-κB signaling pathway, cytoskeleton disorganization, and excessive cell proliferation. In comparison, these abnormalities were not observed in vascular endothelial cells (VECs) derived from the patient's iPSCs. Importantly, the abnormal upregulation of NF-κB target genes in CADASIL VSMCs was diminished by a NOTCH pathway inhibitor, providing a potential therapeutic strategy for CADASIL. Overall, using this iPSC-based disease model, our study identified clues for studying the pathogenic mechanisms of CADASIL and developing treatment strategies for this disease.

Body shape trajectories and the incidence of hypertension in a Mediterranean cohort: The sun study

AIMS

Our aim was to assess the association between trajectories of body-shape across the first 40 years of life and subsequent development of hypertension in a Mediterranean cohort.

METHODS AND RESULTS

We used a group-based modeling approach to assess body shape trajectories from age 5 to 40 years, among 7514 participants included in the SUN study (1999-2016), and assessed the subsequent incidence of hypertension. To create the trajectories, we used a censored normal model as a polynomial function of age. Cox models were used to estimates hazard ratios (HR) for hypertension according to body shape trajectories. Identified trajectories were "childhood lean -mid-life increase", "childhood medium-mid-life stable", " childhood heavy -mid-life decrease", and "childhood heavy -mid-life increase" for women; and "childhood lean-mid-life increase", "childhood medium-mid-life stable", "childhood medium -mid-life increase" and "childhood heavy-mid-life stable" for men. After a follow-up of 63,068 person-years, 865 incident cases of hypertension were found. Among women, compared to those in the "childhood medium-mid-life stable" trajectory, those, in the "childhood heavy -mid-life increase" trajectory showed higher risk to develop hypertension [HR = 1.72 (1.17-2.53)]. In men, compared with those in the "childhood medium-mid-life stable" trajectory, those in the "childhood lean and childhood medium -mid-life increase" and the "childhood heavy- mid-life stable" trajectories showed higher subsequent incidence of hypertension [HR = 1.43 (1.11-1.85), HR = 1.52 (1.17-1.97) and HR = 1.56 (1.14-2.14), respectively] after adjusting for potential confounders (including age, lifestyles, dietary intake, personality traits, physical activity and sedentary behaviors).

CONCLUSIONS

Our results suggest that mid-life increases in body shape or maintaining a heavy body shape during early and middle life in men and childhood heavy-mid-life increase in women is associated with a higher subsequent risk of developing hypertension in this Mediterranean population.

Telomere-dependent and telomere-independent roles of RAP1 in regulating human stem cell homeostasis

RAP1 is a well-known telomere-binding protein, but its functions in human stem cells have remained unclear. Here we generated RAP1-deficient human embryonic stem cells (hESCs) by using CRISPR/Cas9 technique and obtained RAP1-deficient human mesenchymal stem cells (hMSCs) and neural stem cells (hNSCs) via directed differentiation. In both hMSCs and hNSCs, RAP1 not only negatively regulated telomere length but also acted as a transcriptional regulator of RELN by tuning the methylation status of its gene promoter. RAP1 deficiency enhanced self-renewal and delayed senescence in hMSCs, but not in hNSCs, suggesting complicated lineage-specific effects of RAP1 in adult stem cells. Altogether, these results demonstrate for the first time that RAP1 plays both telomeric and nontelomeric roles in regulating human stem cell homeostasis.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Mitochondrial regulation of cardiac aging

Aging is associated with progressive decline in cardiac structure and function. Accumulating evidence in model organisms and humans links cardiac aging to mitochondrial regulation, encompassing a complex interplay of mitochondrial morphology, mitochondrial ROS, mitochondrial DNA mutations, mitochondrial unfolded protein response, nicotinamide adenine dinucleotide levels and sirtuins, as well as mitophagy. This review summarizes the recent discoveries on the mitochondrial regulation of cardiac aging and the possible molecular mechanisms underlying the anti-aging effects, as well as the potential interventions that alleviate aging-related cardiac diseases and attenuate cardiac aging via the regulation of mitochondria.