An investigation of the mechanism of ZiyinDianji decoction in treating follicular dysplasia based on network pharmacology and molecular docking.

Follicular development disorder is a common gynaecological endocrine disease that can cause infertility, menstrual disorders, abortion, and other complications. ZiyinDianji decoction (ZYDJD) is a commonly used traditional Chinese medicine in clinical practice to promote follicular growth and development, but its pharmacological activity and mechanism of action are not clear. We combined network pharmacology with molecular docking and in vivo animal experiments to investigate the mechanism of ZYDJD in follicular development disorder. Cytoscape software was used for constructing ZYDJD-active component-target and PPI networks. GO biological process and KEGG pathway enrichment analyses were performed. The main components and key targets were selected for molecular docking. Finally, animal experiments were conducted for validation. The network pharmacology results showed that ZYDJD contained 83 active components and 159 core targets. The six most important active components were quercetin, luteolin, kaempferol, baicalein, isorhamnetin, and ß-sitosterol, and the most important disease targets were AKT1, TNF, IL-6, and P53. GO analysis mainly involved 470 cell biological processes, including effect on hormones, vascular morphogenesis, development, and cell proliferation. KEGG analysis involved cancer pathways, lipid metabolism pathways, and PI3K/AKT signalling pathways. Molecular docking showed good results, and animal experiments further verified that ZYDJD prevented cyclophosphamide from causing excessive activation of primordial follicles. ZYDJD maintained ovarian reserve and reproductive function by inhibiting the hyperphosphorylation of key molecules of the PI3K/Akt pathway, reducing FOXO3a, thereby ensuring the development of normal follicles. In conclusion, based on network pharmacology, molecular docking, and animal experiments, ZYDJD may act through the PI3K/Akt/FOXO3a pathway.

Mechanisms of neurotransmitter transport and drug inhibition in human VMAT2.

Monoamine neurotransmitters such as dopamine and serotonin control important brain pathways, including movement, sleep, reward and mood1. Dysfunction of monoaminergic circuits has been implicated in various neurodegenerative and neuropsychiatric disorders2. Vesicular monoamine transporters (VMATs) pack monoamines into vesicles for synaptic release and are essential to neurotransmission3-5. VMATs are also therapeutic drug targets for a number of different conditions6-9. Despite the importance of these transporters, the mechanisms of substrate transport and drug inhibition of VMATs have remained elusive. Here we report cryo-electron microscopy structures of the human vesicular monoamine transporter VMAT2 in complex with the antichorea drug tetrabenazine, the antihypertensive drug reserpine or the substrate serotonin. Remarkably, the two drugs use completely distinct inhibition mechanisms. Tetrabenazine binds VMAT2 in a lumen-facing conformation, locking the luminal gating lid in an occluded state to arrest the transport cycle. By contrast, reserpine binds in a cytoplasm-facing conformation, expanding the vestibule and blocking substrate access. Structural analyses of VMAT2 also reveal the conformational changes following transporter isomerization that drive substrate transport into the vesicle. These findings provide a structural framework for understanding the physiology and pharmacology of neurotransmitter packaging by synaptic vesicular transporters.

Structural and functional insights into Spns2-mediated transport of sphingosine-1-phosphate.

Sphingosine-1-phosphate (S1P) is an important signaling sphingolipid that regulates the immune system, angiogenesis, auditory function, and epithelial and endothelial barrier integrity. Spinster homolog 2 (Spns2) is an S1P transporter that exports S1P to initiate lipid signaling cascades. Modulating Spns2 activity can be beneficial in treatments of cancer, inflammation, and immune diseases. However, the transport mechanism of Spns2 and its inhibition remain unclear. Here, we present six cryo-EM structures of human Spns2 in lipid nanodiscs, including two functionally relevant intermediate conformations that link the inward- and outward-facing states, to reveal the structural basis of the S1P transport cycle. Functional analyses suggest that Spns2 exports S1P via facilitated diffusion, a mechanism distinct from other MFS lipid transporters. Finally, we show that the Spns2 inhibitor 16d attenuates the transport activity by locking Spns2 in the inward-facing state. Our work sheds light on Spns2-mediated S1P transport and aids the development of advanced Spns2 inhibitors.

Activation and closed-state inactivation mechanisms of the human voltage-gated KV4 channel complexes.

The voltage-gated ion channel activity depends on both activation (transition from the resting state to the open state) and inactivation. Inactivation is a self-restraint mechanism to limit ion conduction and is as crucial to membrane excitability as activation. Inactivation can occur when the channel is open or closed. Although open-state inactivation is well understood, the molecular basis of closed-state inactivation has remained elusive. We report cryo-EM structures of human KV4.2 channel complexes in inactivated, open, and closed states. Closed-state inactivation of KV4 involves an unprecedented symmetry breakdown for pore closure by only two of the four S4-S5 linkers, distinct from known mechanisms of open-state inactivation. We further capture KV4 in a putative resting state, revealing how voltage sensor movements control the pore. Moreover, our structures provide insights regarding channel modulation by KChIP2 and DPP6 auxiliary subunits. Our findings elucidate mechanisms of closed-state inactivation and voltage-dependent activation of the KV4 channel.

Structural insight into BRCA1-BARD1 complex recruitment to damaged chromatin.

The BRCA1-BARD1 complex directs the DNA double-strand break (DSB) repair pathway choice to error-free homologous recombination (HR) during the S-G2 stages. Targeting BRCA1-BARD1 to DSB-proximal sites requires BARD1-mediated nucleosome interaction and histone mark recognition. Here, we report the cryo-EM structure of BARD1 bound to a ubiquitinated nucleosome core particle (NCPUb) at 3.1 Å resolution and illustrate how BARD1 simultaneously recognizes the DNA damage-induced mark H2AK15ub and DNA replication-associated mark H4K20me0 on the nucleosome. In vitro and in vivo analyses reveal that the BARD1-NCPUb complex is stabilized by BARD1-nucleosome interaction, BARD1-ubiquitin interaction, and BARD1 ARD domain-BARD1 BRCT domain interaction, and abrogating these interactions is detrimental to HR activity. We further identify multiple disease-causing BARD1 mutations that disrupt BARD1-NCPUb interactions and hence impair HR. Together, this study elucidates the mechanism of BRCA1-BARD1 complex recruitment and retention by DSB-flanking nucleosomes and sheds important light on cancer therapeutic avenues.

SARS-CoV-2 viral shedding characteristics and potential evidence for the priority for faecal specimen testing in diagnosis.

This study aimed to identify the specimen type that has high positivity and its proper sampling time for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing to promote diagnostic efficiency. All SARS-CoV-2-infected patients with a laboratory-confirmed diagnosis in Zhoushan City were followed up for viral shedding in respiratory tract specimens and faecal samples. Positivity was analysed both qualitatively and quantitatively by proper statistical approaches with strong testing power. Viral shedding in respiratory tract and faecal specimens was prolonged to 45 and 40 days after the last exposure, respectively. The overall positive rate in respiratory tract specimens was low and relatively unstable, being higher in the early-to-mid stage than in the mid-to-late stage of the disease course. Compared with respiratory tract specimens, faecal samples had a higher viral load, higher overall positive rate, and more stable positivity in different disease courses and varied symptomatic status. Faecal specimens have the potential ability to surpass respiratory tract specimens in virus detection. Testing of faecal specimens in diagnosis, especially for identifying asymptomatic carriers, is recommended. Simultaneously, testing respiratory tract specimens at the early-to-mid stage is better than testing at the mid-to-late stage of the disease course. A relatively small sample size was noted, and statistical approaches were used to address it. Information was missing for both specimen types at different stages of the disease course due to censored data. Our research extends the observed viral shedding in both specimen types and highlights the importance of faecal specimen testing in SARS-CoV-2 diagnosis. Healthcare workers, patients, and the general public may all benefit from our study findings. Disposal of sewage from hospitals and residential areas should be performed cautiously because the virus sheds in faeces and can last for a long time.

Mechanistic and structural insights into histone H2A-H2B chaperone in chromatin regulation.

Histone chaperones include a wide variety of proteins which associate with histones and regulate chromatin structure. The classic H2A-H2B type of histone chaperones, and the chromatin remodeling complex components possessing H2A-H2B chaperone activity, show a broad range of structures and functions. Rapid progress in the structural and functional study of H2A-H2B chaperones extends our knowledge about the epigenetic regulation of chromatin. In this review, we summarize the most recent advances in the understanding of the structure and function of H2A-H2B chaperones that interact with either canonical or variant H2A-H2B dimers. We discuss the current knowledge of the H2A-H2B chaperones, which present no preference for canonical and variant H2A-H2B dimers, describing how they interact with H2A-H2B to fulfill their functions. We also review recent advances of H2A variant-specific chaperones, demarcating how they achieve specific recognition for histone variant H2A.Z and how these interactions regulate chromatin structure by nucleosome editing. We highlight the universal mechanism underlying H2A-H2B dimers recognition by a large variety of histone chaperones. These findings will shed insight into the biological impacts of histone chaperone, chromatin remodeling complex, and histone variants in chromatin regulation.

Epidemiological and Whole Genomic Sequencing Analysis of a Campylobacter jejuni Outbreak in Zhejiang Province, China, May 2019.

Campylobacter is well recognized as the leading cause of bacterial foodborne diarrheal disease worldwide with a very low outbreak reported in China. In May 2019, we investigated an outbreak of Campylobacter jejuni infections among students in a junior high school in Eastern China. Cases were interviewed to identify a common source of contamination. As cases were identified in the same school during a period of time, menus were reviewed and food items included in the questionnaire. Rectal swabs from school kitchen staff and suspected food items (raw chicken) from a local market from where the school food came were examined for C. jejuni. Pulsed-field gel electrophoresis and whole genome sequencing were performed to determine the relatedness of the isolates. To identify the source of the contamination, a case-control study was conducted. Forty-five cases were reported with diarrhea among 1696 students and staff. Stool samples for 10 of the 45 and 5 tested positive for C. jejuni. WGS analysis revealed a 0-4 single nucleotide variation in case-patient isolates. Although we were unable to identify the specific food item, a specific menu was identified as the potential source of the contamination (odds ratios = 20.82; 95% confidence interval = 6.472-66.957). In this menu, chicken was served. A food isolate collected from chicken in Zhejiang province in 2018 was positive for the same identical strain (5-7 single nucleotide polymorphisms). This is one of the few reports in China about outbreak caused by C. jejuni. This investigation illustrates the potential risk of outbreaks caused by Chinese cold dishes of chicken.

Detection of Novel Coronavirus by RT-PCR in Stool Specimen from Asymptomatic Child, China.

We report an asymptomatic child who was positive for a coronavirus by reverse transcription PCR in a stool specimen 17 days after the last virus exposure. The child was virus positive in stool specimens for at least an additional 9 days. Respiratory tract specimens were negative by reverse transcription PCR.

Structural basis for shieldin complex subunit 3-mediated recruitment of the checkpoint protein REV7 during DNA double-strand break repair.

Shieldin complex subunit 3 (SHLD3) is the apical subunit of a recently-identified shieldin complex and plays a critical role in DNA double-strand break repair. To fulfill its function in DNA repair, SHLD3 interacts with the mitotic spindle assembly checkpoint protein REV7 homolog (REV7), but the details of this interaction remain obscure. Here, we present the crystal structures of REV7 in complex with SHLD3's REV7-binding domain (RBD) at 2.2-2.3 Å resolutions. The structures revealed that the ladle-shaped RBD in SHLD3 uses its N-terminal loop and C-terminal α-helix (αC-helix) in its interaction with REV7. The N-terminal loop exhibited a structure similar to those previously identified in other REV7-binding proteins, and the less-conserved αC-helix region adopted a distinct mode for binding REV7. In vitro and in vivo binding analyses revealed that the N-terminal loop and the αC-helix are both indispensable for high-affinity REV7 binding (with low-nanomolar affinity), underscoring the crucial role of SHLD3 αC-helix in protein binding. Moreover, binding kinetics analyses revealed that the REV7 "safety belt" region, which plays a role in binding other proteins, is essential for SHLD3-REV7 binding, as this region retards the dissociation of the RBD from the bound REV7. Together, the findings of our study reveal the molecular basis of the SHLD3-REV7 interaction and provide critical insights into how SHLD3 recognizes REV7.

Animals as amplification hosts in the spread of severe fever with thrombocytopenia syndrome virus: A systematic review and meta-analysis.

OBJECTIVES: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease caused by severe fever with thrombocytopenia syndrome virus (SFTSV). The seroprevalence of anti-SFTSV antibodies specific to SFTSV (IgG or IgM) has been investigated in different animal hosts in many epidemiological studies, but no systematic estimation of seroprevalence has yet been performed. Hence, this meta-analysis was conducted in order to obtain a more comprehensive result to clarify the prevalence of SFTSV in animals. METHODS: A search for all relevant articles was conducted in the major national and international electronic databases up to August 2018. Data on seroprevalence of SFTSV antibodies (IgM and IgG) were extracted as the primary outcome. The pooled seroprevalence rates and 95% confidence intervals (95% CI) were determined. RESULTS: Overall, anti-SFTSV antibodies (IgG or IgM) were detected in 15 animal species. The pooled seroprevalence of anti-SFTSV antibodies was 45.70% in goats and sheep, 36.70% in cattle, 29.50% in dogs, 9.60% in chickens, 3.20% in rodents, and 3.20% in pigs. The seroprevalence of SFTSV in animals that had a confined range was significantly lower than that in free-range animals. SFTSV RNA was detected in 11 animal species, with a carriage rate varying from 0.23% to 26.31%. CONCLUSIONS: SFTSV has a wide spectrum of animal hosts, including domestic and wild animals. The prevalence of SFTSV is high among specific animal species.

Community-based comprehensive measures to prevent severe fever with thrombocytopenia syndrome, China.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging disease caused by the SFTS virus (SFTSV) of the family Bunyaviridae. Since the virus was first isolated in 2009, it has become widespread in China, with an increasing number of cases year on year. Although the disease has been researched extensively in past years, there are still no effective measures to suppress the epidemic situation. This article reports a pilot study of comprehensive measures, including health education and risk communication, weed removal, livestock management, and tick control, to prevent this emerging disease in an endemic region of China. The density of ticks decreased dramatically month by month after acaricides were sprayed in the areas surrounding recreational and agricultural settings. The number of SFTS cases and villages involved declined in the years after the integrated measures were applied. Comprehensive measures, especially community-based tick control, may be a promising means of preventing SFTS in endemic regions.

Structural basis for recognition of 53BP1 tandem Tudor domain by TIRR.

P53-binding protein 1 (53BP1) regulates the double-strand break (DSB) repair pathway choice. A recently identified 53BP1-binding protein Tudor-interacting repair regulator (TIRR) modulates the access of 53BP1 to DSBs by masking the H4K20me2 binding surface on 53BP1, but the underlying mechanism remains unclear. Here we report the 1.76-Å crystal structure of TIRR in complex with 53BP1 tandem Tudor domain. We demonstrate that the N-terminal region (residues 10-24) and the L8-loop of TIRR interact with 53BP1 Tudor through three loops (L1, L3, and L1'). TIRR recognition blocks H4K20me2 binding to 53BP1 Tudor and modulates 53BP1 functions in vivo. Structure comparisons identify a TIRR histidine (H106) that is absent from the TIRR homolog Nudt16, but essential for 53BP1 Tudor binding. Remarkably, mutations mimicking TIRR binding modules restore the disrupted binding of Nudt16-53BP1 Tudor. Our studies elucidate the mechanism by which TIRR recognizes 53BP1 Tudor and functions as a cellular inhibitor of the histone methyl-lysine readers.

Seroprevalence of severe fever with thrombocytopenia syndrome virus in China: A systematic review and meta-analysis.

OBJECTIVE: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by a novel bunyavirus-SFTSV. The seroprevalence of anti-SFTSV antibodies including immunoglobulin G (IgG) and immunoglobulin M (IgM), specific to SFTSV in the general population has been investigated in various epidemiological studies with inconsistent results. Here, we clarify this discrepancy and reach a more comprehensive result by mean of a meta-analysis. METHODS: All relevant articles were searched in the electronic databases (PubMed, Web of science, Embase, Chinese National Knowledge Infrastructure database, Chinese Wanfang database) up to November 2016. The pooled seroprevalence and 95% confidence intervals (95% CIs) were calculated by random- or fixed- model on the basis of heterogeneity. RESULTS: In total, 21 studies containing 23,848 blood samples from 7 provinces were included in this meta-analysis. The minimum and maximum reported seroprevalences of SFTSV among humans in China were 0.23% and 9.17%, respectively. The overall pooled seroprevalence of SFTSV antibodies was 4.3% (95%CI: 3.2%-5.5%). The pooled prevalence was 5.9% (95%CI: 4.7%-7.0%) in Zhejiang province, 4.9% (95%CI: 4.1-5.8%) in Anhui province, 3.9% (95%CI: 1.3%-6.4%) in Shandong province, and 0.7% (95%CI: 0.2%-1.1%) in Jiangsu province. Stratified by occupation, the pooled prevalence of farmer was 6.1% (95%CI: 3.4%-8.9%) and others (mainly are students) was 3.3% (95%CI: 2.4%-4.2%). Additionally, seroprevalence of SFTSV in people who lived in the same village with the patient were higher than that of people who lived in a different village. Seropositive rates in sampling years after 2012 were higher than that before 2012. The prevalence of SFTSV did not differ by age or gender. Sensitive analysis by omitting one study at a time indicated the results of the pooled seroprevalence were robust. CONCLUSIONS: Seroprevalence of SFTSV among healthy population in central and eastern China is high. Surveillance efforts on mild or asymptomatic infections among endemic persons are needed.

[A study on the treatment of chronic hepatitis B with YMDD mutation].

OBJECTIVE: To explore the strategy for the treatment of chronic hepatitis B with YMDD mutation. METHODS: A total of 120 chronic hepatitis B patients with YMDD mutation were randomly assigned into four groups. In group A, patients received adefovir dipivoxil for 48 weeks. In group B, patients received adefovir dipivoxil in combination with lamivudine during the first 12 weeks and adefovir dipivoxil only for the following 36 weeks. In group C, patients received adefovir dipivoxil in combination with lamivudine for 48 weeks. In group D, patients received entecavir for 48 weeks. RESULTS: The rate of rebound of alanine aminotransferase (ALT) was 30.0% (9/30), 10.0% (3/30), 6.7% (2/30), 10.0% (3/30) (P < 0.05) during the first 12 weeks, and one patient with severe hepatitis was found in group A. The positive rate of YMDD mutation was 17.9%, 0, 0, 0 at week 12. There was no significant difference in the level of ALT and the rate of HBeAg seroconversion after 48-week treatment (P > 0.05). At week 48, there was significant difference in the ALT normalization rate and undetectable HBV DNA rate between group C and group A, and also between group D and group A, and the rate of drug resistant genotype was 6.9%, 6.7%, 0, 0. Two patients had rtN236T mutation in group A, and one patient had rtN236T mutation and another one had rtA181V mutation in group B. CONCLUSION: Adefovir dipivoxil in combination with lamivudine or entecavir are safe and effective therapies for chronic hepatitis B patients with YMDD mutation.