We report a 2-family cluster of persons infected with severe acute respiratory syndrome coronavirus 2 in the city of Zhoushan, Zhejiang Province, China, during January 2020. The infections resulted ...from contact with an infected but potentially presymptomatic traveler from the city of Wuhan in Hubei Province.
Glucose‐6‐phosphate dehydrogenase (G6PD) is a key enzyme in the pentose phosphate pathway (PPP) and plays an essential role in the oxidative stress response by producing NADPH, the main intracellular ...reductant. G6PD deficiency is the most common human enzyme defect, affecting more than 400 million people worldwide. Here, we show that G6PD is negatively regulated by acetylation on lysine 403 (K403), an evolutionarily conserved residue. The K403 acetylated G6PD is incapable of forming active dimers and displays a complete loss of activity. Knockdown of G6PD sensitizes cells to oxidative stress, and re‐expression of wild‐type G6PD, but not the K403 acetylation mimetic mutant, rescues cells from oxidative injury. Moreover, we show that cells sense extracellular oxidative stimuli to decrease G6PD acetylation in a SIRT2‐dependent manner. The SIRT2‐mediated deacetylation and activation of G6PD stimulates PPP to supply cytosolic NADPH to counteract oxidative damage and protect mouse erythrocytes. We also identified KAT9/ELP3 as a potential acetyltransferase of G6PD. Our study uncovers a previously unknown mechanism by which acetylation negatively regulates G6PD activity to maintain cellular NADPH homeostasis during oxidative stress.
Synopsis
The pentose phosphate pathway plays an important role in the oxidative stress response by supplying the reductant NADPH. SIRT2‐mediated deacetylation and activation of the glucose‐6‐phosphate dehydrogenase, the rate‐limiting enzyme in this pathway, stimulates the production of cytosolic NADPH to counteract oxidative damage.
K403 acetylation decreases G6PD activity by inhibiting dimer formation.
SIRT2 and KAT9/ELP3 regulate G6PD K403 acetylation.
Regulation of G6PD K403 acetylation modulates NADPH homeostasis and cell survival during oxidative stress.
Following oxidative stress, production of the reductant NADPH via the pentose phosphate pathway is stimulated by SIRT2‐mediated deacetylation and activation of G6PD.
Acute lymphoblastic leukemia (ALL) is the most common malignancy among children. The trial Chinese Children Leukemia Group (CCLG)‐ALL 2008 was a prospective clinical trial designed to improve ...treatment outcome of childhood ALL through the first nation‐wide collaborative study in China. Totally 2231 patients were recruited from ten tertiary hospitals in eight cities. The patients were stratified according to clinical‐biological characteristics and early treatment response. Standard risk (SR) and intermediate risk (IR) groups were treated with a modified BFM based protocol, and there was 25%‐50% dose reduction during intensification phases in the SR group. Patients in high risk (HR) group received a more intensive maintenance treatment. Minimal residual disease (MRD) monitoring with treatment adjustment was performed in two hospitals (the MRD group). Complete remission (CR) was achieved in 2100 patients (94.1%). At five years, the estimate for overall survival (OS) and event‐free survival (EFS) of the whole group was 85.3% and 79.9%, respectively. The cumulative incidence of relapse (CIR) was 15.3% at five years. The OS, EFS and CIR for the SR group were 91.5%, 87.9%, and 9.7%, respectively. The outcome of the MRD group is better than the non‐MRD group (5y‐EFS: 82.4% vs 78.3%, P = .038; 5y‐CIR: 10.7% vs 18.0%, P < .001). Our results demonstrated that the large‐scale multicenter trial for pediatric ALL was feasible in China. Dose reduction in the SR group could achieve high EFS. MRD‐based risk stratification might improve the treatment outcome for childhood ALL.
Here an efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is reported, representing the first generation of α‐imino copper carbenes from ...alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities. Moreover, an asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities (up to 98:2 e.r.) by employing BOX‐Cu complexes as chiral catalysts. Thus, this protocol constitutes the first example of an asymmetric azide–alkyne cyclization. The proposed mechanistic rationale for this cascade cyclization is further supported by theoretical calculations.
An efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is disclosed, enabling divergent synthesis of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities, representing the first generation of α‐imino copper carbenes directly from alkynes. The asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities.
Viral infection triggers host innate immune responses, which primarily include the activation of type I interferon (IFN) signaling and inflammasomes. Here, we report that Zika virus (ZIKV) infection ...triggers NLRP3 inflammasome activation, which is further enhanced by viral non‐structural protein NS1 to benefit its replication. NS1 recruits the host deubiquitinase USP8 to cleave K11‐linked poly‐ubiquitin chains from caspase‐1 at Lys134, thus inhibiting the proteasomal degradation of caspase‐1. The enhanced stabilization of caspase‐1 by NS1 promotes the cleavage of cGAS, which recognizes mitochondrial DNA release and initiates type I IFN signaling during ZIKV infection. NLRP3 deficiency increases type I IFN production and strengthens host resistance to ZIKVin vitro and in vivo. Taken together, our work unravels a novel antagonistic mechanism employed by ZIKV to suppress host immune response by manipulating the interplay between inflammasome and type I IFN signaling, which might guide the rational design of therapeutics in the future.
Synopsis
Zika virus promotes NLRP3 inflammasome activation by stabilizing caspase‐1 to suppress cGAS‐mediated type I IFN signaling.
The non‐structural protein NS1 enhances ZIKV‐induced NLRP3 inflammasome activation.
NS1 stabilizes caspase‐1 by blocking its proteasomal degradation.
NS1 recruits USP8 to cleave K11‐linked poly‐ubiquitin chains from caspase‐1 at Lys134.
ZIKV enhances inflammasome activation to benefit its infection by inhibiting type I IFN signaling.
NS1‐mediated stabilization of caspase‐1 promotes the cleavage of cGAS.
The Zika virus promotes NLRP3 inflammasome activation by stabilizing caspase‐1 to suppress cGAS‐mediated type I IFN signaling.
While splicing differences between tissues, sexes and species are well documented, little is known about the extent and the nature of splicing changes that take place during human or mammalian ...development and aging. Here, using high‐throughput transcriptome sequencing, we have characterized splicing changes that take place during whole human lifespan in two brain regions: prefrontal cortex and cerebellum. Identified changes were confirmed using independent human and rhesus macaque RNA‐seq data sets, exon arrays and PCR, and were detected at the protein level using mass spectrometry. Splicing changes across lifespan were abundant in both of the brain regions studied, affecting more than a third of the genes expressed in the human brain. Approximately 15% of these changes differed between the two brain regions. Across lifespan, splicing changes followed discrete patterns that could be linked to neural functions, and associated with the expression profiles of the corresponding splicing factors. More than 60% of all splicing changes represented a single splicing pattern reflecting preferential inclusion of gene segments potentially targeting transcripts for nonsense‐mediated decay in infants and elderly.
Human brain transcriptome analysis revealed widespread age‐related splicing changes in the prefrontal cortex and cerebellum. While most of the splicing changes take place in development, approximately one‐third of them extends into aging.
Synopsis
Human brain transcriptome analysis revealed widespread age‐related splicing changes in the prefrontal cortex and cerebellum. While most of the splicing changes take place in development, approximately one‐third of them extends into aging.
More than one‐third of genes expressed in the human brain change splicing with age.
Approximately 30% of observed splicing changes occur in aging.
Age‐related splicing patterns are largely conserved between the human and macaque brains.
High frequency of intron retention events suggests the role of nonsense‐mediated decay in age‐related gene expression regulation.
Saliva in the diagnosis of diseases Zhang, Chen-Zi; Cheng, Xing-Qun; Li, Ji-Yao ...
International journal of oral science,
09/2016, Letnik:
8, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Saliva is secreted from the salivary glands and has multiple functions, including mouth cleaning and protection, antibacterial effects and digestion. With the rapid advancement in salivaomics, saliva ...is well recognized as a pool of biological markers. Saliva, as a non-invasive and safe source, could be a substitute for blood in the diagnosis and prognosis of diseases. This review summarizes the latest advancements in saliva-related studies and addresses the potential value of saliva in the early diagnosis of oral diseases, such as dental caries and periodontal disease, as well as cancer, diabetes and other systemic disorders. Saliva biomarkers range from changes in the biochemical indices of DNA, RNA and proteins to the diversification of microbiota structures. This study integrates data reported in the recent literature and discusses the clinical significance and prospects for the application of saliva in the early diagnosis of diseases, translational medicine and precision medicine.
Peroxisomes account for ~35% of total H2O2 generation in mammalian tissues. Peroxisomal ACOX1 (acyl‐CoA oxidase 1) is the first and rate‐limiting enzyme in fatty acid β‐oxidation and a major producer ...of H2O2. ACOX1 dysfunction is linked to peroxisomal disorders and hepatocarcinogenesis. Here, we show that the deacetylase sirtuin 5 (SIRT5) is present in peroxisomes and that ACOX1 is a physiological substrate of SIRT5. Mechanistically, SIRT5‐mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation in both cultured cells and mouse livers. Deletion of SIRT5 increases H2O2 production and oxidative DNA damage, which can be alleviated by ACOX1 knockdown. We show that SIRT5 downregulation is associated with increased succinylation and activity of ACOX1 and oxidative DNA damage response in hepatocellular carcinoma (HCC). Our study reveals a novel role of SIRT5 in inhibiting peroxisome‐induced oxidative stress, in liver protection, and in suppressing HCC development.
Synopsis
This study reveals a role for SIRT5 in regulating peroxisomal H2O2 and ROS homeostasis and indicates its potential function in liver protection and hepatocellular carcinoma suppression.
SIRT5 is localized in peroxisomes where it controls H2O2 metabolism.
SIRT5‐mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation.
SIRT5 downregulation increases ACOX1 activity and oxidative DNA damage response in HCC.
This study reveals a role for SIRT5 in regulating peroxisomal H2O2 and ROS homeostasis and indicates its potential function in liver protection and hepatocellular carcinoma suppression.
In crop plants, a high-density genetic linkage map is essential for both genetic and genomic researches. The complexity and the large size of wheat genome have hampered the acquisition of a ...high-resolution genetic map. In this study, we report a high-density genetic map based on an individual mapping population using the Affymetrix Wheat660K single-nucleotide polymorphism (SNP) array as a probe in hexaploid wheat. The resultant genetic map consisted of 119 566 loci spanning 4424.4 cM, and 119 001 of those loci were SNP markers. This genetic map showed good collinearity with the 90 K and 820 K consensus genetic maps and was also in accordance with the recently released wheat whole genome assembly. The high-density wheat genetic map will provide a major resource for future genetic and genomic research in wheat. Moreover, a comparative genomics analysis among gramineous plant genomes was conducted based on the high-density wheat genetic map, providing an overview of the structural relationships among theses gramineous plant genomes. A major stable quantitative trait locus (QTL) for kernel number per spike was characterized, providing a solid foundation for the future high-resolution mapping and map-based cloning of the targeted QTL.
Severe COVID-19 disease caused by SARS-CoV-2 is frequently accompanied by dysfunction of the lungs and extrapulmonary organs. However, the organotropism of SARS-CoV-2 and the port of virus entry for ...systemic dissemination remain largely unknown. We profiled 26 COVID-19 autopsy cases from four cohorts in Wuhan, China, and determined the systemic distribution of SARS-CoV-2. SARS-CoV-2 was detected in the lungs and multiple extrapulmonary organs of critically ill COVID-19 patients up to 67 days after symptom onset. Based on organotropism and pathological features of the patients, COVID-19 was divided into viral intrapulmonary and systemic subtypes. In patients with systemic viral distribution, SARS-CoV-2 was detected in monocytes, macrophages, and vascular endothelia at blood-air barrier, blood-testis barrier, and filtration barrier. Critically ill patients with long disease duration showed decreased pulmonary cell proliferation, reduced viral RNA, and marked fibrosis in the lungs. Permanent SARS-CoV-2 presence and tissue injuries in the lungs and extrapulmonary organs suggest direct viral invasion as a mechanism of pathogenicity in critically ill patients. SARS-CoV-2 may hijack monocytes, macrophages, and vascular endothelia at physiological barriers as the ports of entry for systemic dissemination. Our study thus delineates systemic pathological features of SARS-CoV-2 infection, which sheds light on the development of novel COVID-19 treatment.
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