Explore the vast range of titles available.

Porcine reproductive and respiratory syndrome (PRRS) caused by the PRRS virus (PRRSV) is an important swine disease worldwide. PRRSV has a limited tropism for certain cells, which may at least in part be attributed to the expression of the necessary cellular molecules serving as the virus receptors or factors on host cells for virus binding or entry. However, these molecules conferring PRRSV infection have not been fully characterized. Here we show the identification of non-muscle myosin heavy chain 9 (MYH9) as an essential factor for PRRSV infection using the anti-idiotypic antibody specific to the PRRSV glycoprotein GP5. MYH9 physically interacts with the PRRSV GP5 protein via its C-terminal domain and confers susceptibility of cells to PRRSV infection. These findings indicate that MYH9 is an essential factor for PRRSV infection and provide new insights into PRRSV-host interactions and viral entry, potentially facilitating development of control strategies for this important swine disease.

Myocardial infarction (MI) is one of the most serious cardiovascular diseases associated with myocardial ischemia/reperfusion (I/R) injury. Glaucocalyxin A (GLA) is a biologically active ent-kauranoid diterpenoid that has been found to ameliorate myocardial I/R injury in mice. However, the mechanism has not been fully investigated. In the present study, we aimed to investigate the effect of GLA on rat cardiomyocytes H9c2 cells exposed to hypoxia/reoxygenation (H/R). The results showed that GLA treatment improved cell viability of H/R-stimulated H9c2 cells. Administration with GLA suppressed the H/R-stimulated reactive oxygen species (ROS) production in H9c2 cells. GLA also elevated the activities of antioxidant enzymes, including superoxide dismutase and glutathione peroxidase in H/R-stimulated H9c2 cells. Moreover, GLA prevented H/R-stimulated cell apoptosis in H9c2 cells, as evidenced by increased bcl-2 expression, decreased bax expression, as well as reduced caspase-3 activity. Furthermore, GLA enhanced the activation of protein kinase B (Akt)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in H9c2 cells exposed to H/R. Additionally, treatment with LY294002 reserved the protective effects of GLA on H/R-stimulated oxidative injury in H9c2 cells. In conclusion, these findings suggested that GLA protected H9c2 cells from H/R-stimulated oxidative damage, which was mediated by the Akt/Nrf2/HO-1 signaling pathway. Thus, GLA might be a promising therapeutic agent for the prevention and treatment of myocardial I/R.

Introduction: COVID-19 patients with hypotension and hypoxemia had a significantly worse outcome. The purpose of this research was to ascertain the risk factors affecting the prognoses of these patients and to develop appropriate prognostic prediction tools. Methods: From March 1, 2020, to April 16, 2020, a retrospective cohort analysis of COVID-19 patients with hypotension and hypoxemia was performed. The univariate and multivariate analyses were performed to identify the associated risk factors influencing the prognosis of COVID-19 patients with hypotension and hypoxemia, and the selected variables were then utilized to construct and validate the prediction model for these patients. Results: Three hundred and twenty-seven COVID-19 patients with hypotension and hypoxemia who met the inclusion and exclusion criteria were included in this study. Age, temperature, troponin, and blood glucose were related to mortality in COVID-19 patients with hypotension and hypoxemia in both univariate and multivariate analyses. The MFP model (multiple fractional polynomial model), full model, and stepwise model were utilized to build the prediction model, and their AUCs were, respectively, 0.902 (0.868, 0.936), 0.902 (0.868, 0.936), and 0.902 (0.868, 0.936). Because the sample size for this research was limited, we utilized bootstrapping for internal validation. The AUCs of Bootstrap full and Bootstrap stepwise were 0.902 (0.867, 0.936) and 0.902 (0.868, 0.936), respectively. Conclusion: Age, temperature, troponin, and blood glucose levels were associated with mortality in COVID-19 patients with hypotension and hypoxemia. Additionally, the prediction model developed using the variables above showed a high predictive value for predicting the prognosis of these individuals.

Serotonin, or 5-hydroxytryptamine (5-HT), is a well-known neurotransmitter that plays vital roles in neural activities and social behaviors. Clinically, deficiency of serotonin is linked with many psychiatric disorders. Interestingly, a large proportion of serotonin is also produced outside the central nervous system (CNS). There is increasing evidence demonstrating important roles of serotonin in the peripheral tissues. Here, we will describe the multiple biological functions of serotonin in hematopoietic system, such as development of hematopoietic stem and progenitor cells (HSPCs), differentiation of hematopoietic cells, maintenance of vascular system, and relationship with hematological diseases. The roles of serotonin in inflammatory responses mediated by hematopoietic cells as well as in liver regeneration are also discussed. Our recent understandings of the impact of serotonin on hematopoietic system, immune responses, and tissue regeneration support utilization of serotonin as a potential therapeutic target for the treatment of hematological diseases and organ repair in clinic.

N 6 -methyladenosine modification of mRNA determines cell fate decisions during the specification of the first haematopoietic stem cells in zebrafish. Stem cell specification by m 6 A Adding modified N 6 -methyladenosine (m 6 A) on messenger RNA (mRNA) has recently been reported to modulate mRNA translation and degradation. However, the effects of the modification on vertebrate development are so far unclear. Feng Liu and colleagues show that addition of m 6 A determines cell fate during the specification of the earliest haematopoietic stem cell in zebrafish. Blocking addition of this modification on genes that regulate Notch signalling maintains the endothelial fate of progenitors that should be specified as the earliest haematopoietic stem cell progenitors. N 6 -methyladenosine (m 6 A) has been identified as the most abundant modification on eukaryote messenger RNA (mRNA) 1 . Although the rapid development of high-throughput sequencing technologies has enabled insight into the biological functions of m 6 A modification 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , the function of m 6 A during vertebrate embryogenesis remains poorly understood. Here we show that m 6 A determines cell fate during the endothelial-to-haematopoietic transition (EHT) to specify the earliest haematopoietic stem/progenitor cells (HSPCs) during zebrafish embryogenesis. m 6 A-specific methylated RNA immunoprecipitation combined with high-throughput sequencing (MeRIP–seq) and m 6 A individual-nucleotide-resolution cross-linking and immunoprecipitation with sequencing (miCLIP–seq) analyses reveal conserved features on zebrafish m 6 A methylome and preferential distribution of m 6 A peaks near the stop codon with a consensus RRACH motif. In mettl3 -deficient embryos, levels of m 6 A are significantly decreased and emergence of HSPCs is blocked. Mechanistically, we identify that the delayed YTHDF2-mediated mRNA decay of the arterial endothelial genes notch1a and rhoca contributes to this deleterious effect. The continuous activation of Notch signalling in arterial endothelial cells of mettl3 -deficient embryos blocks EHT, thereby repressing the generation of the earliest HSPCs. Furthermore, knockdown of Mettl3 in mice confers a similar phenotype. Collectively, our findings demonstrate the critical function of m 6 A modification in the fate determination of HSPCs during vertebrate embryogenesis.

The earliest HSCs are derived from haemogenic endothelium via endothelial-to-haematopoietic transition during vertebrate embryogenesis; however, the underlying mechanism is largely unclear. Here we show that interplay of Smad1/5 and ERK signalling is essential for haemogenic endothelium-based HSC emergence. Smad1/5 directly inhibits erk expression through recruiting HDAC1 to and inducing de-acetylation of the erk promoter in endothelial cells. Over-activated ERK signalling conferred by inhibition of Smad1/5 promotes the arterial endothelial cell fate and constitutively strengthens the tight junction between endothelial cells, thereby repressing the specification of haemogenic endothelium and the following endothelial-to-haematopoietic transition process. These findings provide new insights into the in vitro generation of transplantable HSCs for potential clinical applications. Vertebrate haematopoietic stem cells are produced from the haemogenic endothelium by an endothelial-to-haematopoietic transition. Here, the authors show that, in zebrafish and mice, this transition depends on interplay of Smad transcription factors and the ERK signalling pathway.

N6-methyladenosine (m6A) has been identified as the most abundant modification on eukaryote messenger RNA (mRNA). Although the rapid development of high-throughput sequencing technologies has enabled insight into the biological functions of m6A modification, the function of m6A during vertebrate embryogenesis remains poorly understood. Here we show that m6A determines cell fate during the endothelial-to-haematopoietic transition (EHT) to specify the earliest haematopoietic stem/ progenitor cells (HSPCs) during zebrafish embryogenesis. m6A-specific methylated RNA immunoprecipitation combined with high-throughput sequencing (MeRIP-seq) and m6A individual-nucleotide-resolution cross-linking and immunoprecipitation with sequencing (miCLIP-seq) analyses reveal conserved features on zebrafish m6A methylome and preferential distribution of m6A peaks near the stop codon with a consensus RRACH motif. In mettl3-deficient embryos, levels of m6A are significantly decreased and emergence of HSPCs is blocked. Mechanistically, we identify that the delayed YTHDF2-mediated mRNA decay of the arterial endothelial genes notchla and rhoca contributes to this deleterious effect. The continuous activation of Notch signalling in arterial endothelial cells of mettl3-deficient embryos blocks EHT, thereby repressing the generation of the earliest HSPCs. Furthermore, knockdown of Mettl3 in mice confers a similar phenotype. Collectively, our findings demonstrate the critical function of m6A modification in the fate determination of HSPCs during vertebrate embryogenesis.