The complete assembly of human LAT1-4F2hc complex provides insights into its regulation, function and localisation

The LAT1-4F2hc complex (SLC7A5-SLC3A2) facilitates uptake of essential amino acids, hormones and drugs. Its dysfunction is associated with many cancers and immune/neurological disorders. Here, we apply native mass spectrometry (MS)-based approaches to provide evidence of super-dimer formation (LAT1-4F2hc)2. When combined with lipidomics, and site-directed mutagenesis, we discover four endogenous phosphatidylethanolamine (PE) molecules at the interface and C-terminus of both LAT1 subunits. We find that interfacial PE binding is regulated by 4F2hc-R183 and is critical for regulation of palmitoylation on neighbouring LAT1-C187. Combining native MS with mass photometry (MP), we reveal that super-dimerization is sensitive to pH, and modulated by complex N-glycans on the 4F2hc subunit. We further validate the dynamic assemblies of LAT1-4F2hc on plasma membrane and in the lysosome. Together our results link PTM and lipid binding with regulation and localisation of the LAT1-4F2hc super-dimer.

Cryo-EM structure of the human Asc-1 transporter complex

The Alanine-Serine-Cysteine transporter 1 (Asc-1 or SLC7A10) forms a crucial heterodimeric transporter complex with 4F2hc (SLC3A2) through a covalent disulfide bridge. This complex enables the sodium-independent transport of small neutral amino acids, including L-Alanine (L-Ala), Glycine (Gly), and D-Serine (D-Ser), within the central nervous system (CNS). D-Ser and Gly are two key endogenous glutamate co-agonists that activate N-methyl-d-aspartate (NMDA) receptors by binding to the allosteric site. Mice deficient in Asc-1 display severe symptoms such as tremors, ataxia, and seizures, leading to early postnatal death. Despite its physiological importance, the functional mechanism of the Asc-1-4F2hc complex has remained elusive. Here, we present cryo-electron microscopy (cryo-EM) structures of the human Asc-1-4F2hc complex in its apo state, D-Ser bound state, and L-Ala bound state, resolved at 3.6 Å, 3.5 Å, and 3.4 Å, respectively. Through detailed structural analysis and transport assays, we uncover a comprehensive alternating access mechanism that underlies conformational changes in the complex. In summary, our findings reveal the architecture of the Asc-1 and 4F2hc complex and provide valuable insights into substrate recognition and the functional cycle of this essential transporter complex.

Cryo-EM structures of the human NaS1 and NaDC1 transporters revealed the elevator transport and allosteric regulation mechanism

The solute carrier 13 (SLC13) family comprises electrogenic sodium ion-coupled anion cotransporters, segregating into sodium ion-sulfate cotransporters (NaSs) and sodium ion-di- and-tricarboxylate cotransporters (NaDCs). NaS1 and NaDC1 regulate sulfate homeostasis and oxidative metabolism, respectively. NaS1 deficiency affects murine growth and fertility, while NaDC1 affects urinary citrate and calcium nephrolithiasis. Despite their importance, the mechanisms of substrate recognition and transport remain insufficiently characterized. In this study, we determined the cryo-electron microscopy structures of human NaS1, capturing inward-facing and combined inward-facing/outward-facing conformations within a dimer both in apo and sulfate-bound states. In addition, we elucidated NaDC1's outward-facing conformation, encompassing apo, citrate-bound, and N-(p-amylcinnamoyl) anthranilic acid (ACA) inhibitor-bound states. Structural scrutiny illuminates a detailed elevator mechanism driving conformational changes. Notably, the ACA inhibitor unexpectedly binds primarily anchored by transmembrane 2 (TM2), Loop 10, TM11, and TM6a proximate to the cytosolic membrane. Our findings provide crucial insights into SLC13 transport mechanisms, paving the way for future drug design.

Structural basis for the inhibition mechanism of the DNA polymerase holoenzyme from mpox virus

There are three key components at the core of the mpox virus (MPXV) DNA polymerase holoenzyme: DNA polymerase F8, processivity factors A22, and the Uracil-DNA glycosylase E4. The holoenzyme is recognized as a vital antiviral target because MPXV replicates in the cytoplasm of host cells. Nucleotide analogs such as cidofovir and cytarabine (Ara-C) have shown potential in curbing MPXV replication and they also display promise against other poxviruses. However, the mechanism behind their inhibitory effects remains unclear. Here, we present the cryo-EM structure of the DNA polymerase holoenzyme F8/A22/E4 bound with its competitive inhibitor Ara-C-derived cytarabine triphosphate (Ara-CTP) at an overall resolution of 3.0 Å and reveal its inhibition mechanism. Ara-CTP functions as a direct chain terminator in proximity to the deoxycytidine triphosphate (dCTP)-binding site. The extra hydrogen bond formed with Asn665 makes it more potent in binding than dCTP. Asn665 is conserved among eukaryotic B-family polymerases.

The cryo-EM structure of homotetrameric attachment glycoprotein from langya henipavirus

Langya Henipavirus (LayV) infection is an emerging zoonotic disease that has been causing respiratory symptoms in China since 2019. For virus entry, LayV's genome encodes the fusion protein F and the attachment glycoprotein G. However, the structural and functional information regarding LayV-G remains unclear. In this study, we revealed that LayV-G cannot bind to the receptors found in other HNVs, such as ephrin B2/B3, and it shows different antigenicity from HeV-G and NiV-G. Furthermore, we determined the near full-length structure of LayV-G, which displays a distinct mushroom-shaped configuration, distinguishing it from other attachment glycoproteins of HNV. The stalk and transmembrane regions resemble the stem and root of mushroom and four downward-tilted head domains as mushroom cap potentially interact with the F protein and influence membrane fusion process. Our findings enhance the understanding of emerging HNVs that cause human diseases through zoonotic transmission and provide implication for LayV related vaccine development.

Structural insight into the assembly and working mechanism of helicase-primase D5 from Mpox virus

The Mpox pandemic, caused by the Mpox virus (or monkeypox virus, MPXV), has gained global attention. The D5 protein, a putative helicase-primase found in MPXV, plays a vital role in viral replication and genome uncoating. Here we determined multiple cryo-EM structures of full-length hexameric D5 in diverse states. These states were captured during ATP hydrolysis while moving along the single-stranded DNA (ssDNA) track. Through comprehensive structural analysis combined with the helicase activity system, we revealed that when the primase domain is truncated or the interaction between the primase and helicase domains is disrupted, the double-stranded DNA (dsDNA) unwinds into ssDNA, suggesting a critical regulatory role of the primase domain. Two transition states bound with ssDNA substrate during unwinding reveals that two ATP molecules were consumed to drive DNA moving forward two nucleotides. Collectively, our findings shed light on the molecular mechanism that links ATP hydrolysis to the DNA unwinding in poxviruses.

[Doublecortin-like kinase 1 activates Hippo pathway to promote migration, invasion and proliferation of pancreatic cancer cells]

Objective: To explore the mechanism of Doublecortin-like kinase 1 (DCLK1) in promoting cell migration, invasion and proliferation in pancreatic cancer. Methods: The correlation between DCLK1 and Hippo pathway was analyzed using TCGA and GTEx databases and confirmed by fluorescence staining of pancreatic cancer tissue microarrays. At the cellular level, immunofluorescence staining of cell crawls and western blot assays were performed to clarify whether DCLK1 regulates yes associated protein1 (YAP1), a downstream effector of the Hippo pathway. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to analyze the expressions of YAP1 binding transcription factor TEA-DNA binding proteins (TEAD) and downstream malignant behavior-promoting molecules CYR61, EDN1, AREG, and CTGF. Transwell test of the DCLK1-overexpressing cells treated with the Hippo pathway inhibitor Verteporfin was used to examine whether the malignant behavior-promoting ability was blocked. Analysis of changes in the proliferation index of experimental cells used real-time label-free cells. Results: TCGA combined with GTEx data analysis showed that the expressions of DCLK1 and YAP1 molecules in pancreatic cancer tissues were significantly higher than those in adjacent tissues (P<0.05). Moreover, DCLK1was positively correlated with the expressions of many effectors in the Hippo pathway, including LATS1 (r=0.53, P<0.001), LATS2 (r=0.34, P<0.001), MOB1B (r=0.40, P<0.001). In addition, the tissue microarray of pancreatic cancer patients was stained with multicolor fluorescence, indicated that the high expression of DCLK1 in pancreatic cancer patients was accompanied by the up-regulated expression of YAP1. The expression of DCLK1 in pancreatic cancer cell lines was analyzed by the CCLE database. The results showed that the expression of DCLK1 in AsPC-1 and PANC-1 cells was low. Thus, we overexpressed DCLK1 in AsPC-1 and PANC-1 cell lines and found that DCLK1 overexpression in pancreatic cancer cell lines promoted YAP1 expression and accessible to the nucleus. In addition, DCLK1 up-regulated the expression of YAP1 binding transcription factor TEAD and increased the mRNA expression levels of downstream malignant behavior-promoting molecules. Finally, Verteporfin, an inhibitor of the Hippo pathway, could antagonize the cell's malignant behavior-promoting ability mediated by high expression of DCLK1. We found that the number of migrated cells with DCLK1 overexpressing AsPC-1 group was 68.33±7.09, which was significantly higher than 22.00±4.58 of DCLK1 overexpressing cells treated with Verteporfin (P<0.05). Similarly, the migration number of PANC-1 cells overexpressing DCLK1 was 65.66±8.73, which was significantly higher than 37.00±6.00 of the control group and 32.33±9.61 of Hippo pathway inhibitor-treated group (P<0.05). Meanwhile, the number of invasive cells in the DCLK1-overexpressed group was significantly higher than that in the DCLK1 wild-type group cells, while the Verteporfin-treated DCLK1-overexpressed cells showed a significant decrease. In addition, we monitored the cell proliferation index using the real-time cellular analysis (RTCA) assay, and the proliferation index of DCLK1-overexpressed AsPC-1 cells was 0.66±0.04, which was significantly higher than 0.38±0.01 of DCLK1 wild-type AsPC-1 cells (P<0.05) as well as 0.05±0.03 of DCLK1-overexpressed AsPC1 cells treated with Verteporfin (P<0.05). PANC-1 cells showed the same pattern, with a proliferation index of 0.77±0.04 for DCLK1-overexpressed PANC-1 cells, significantly higher than DCLK1-overexpressed PANC1 cells after Verteporfin treatment (0.14±0.05, P<0.05). Conclusion: The expression of DCLK1 is remarkably associated with the Hippo pathway, it promotes the migration, invasion, and proliferation of pancreatic cancer cells by activating the Hippo pathway.

[Dermatophagoides farinae induces conjunctival epithelial cell damage to promote neutrophil migration and neutrophil extracellular traps formation]

OBJECTIVE

To investigate the mechanisms underlying allergic conjunctivitis caused by conjunctival epithelial cell damage, neutrophil migration and neutrophil extracellular traps (NETs) formation induced by crude extracts of Dermatophagoides farinae mite (CDM).

METHODS

Human conjunctival epithelial cells were stimulated with 500, 1 000, 2 000, 4 000 ng/mL, and the expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and IL-8 were detected using quantitative real-time PCR (qPCR) assay and enzyme-linked immunosorbent assay (ELISA). The culture supernatant of human conjunctival epithelial cells was collected and co-cultured with neutrophils. Neutrophil migration was measured using Transwell migration assay, and the expression of NETs markers myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) was quantified using immunofluorescence staining. Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), and then NETs were collected for treatment of human conjunctival epithelial cells. Cell apoptosis was detected using flow cytometry, and the levels of IL-6, TNF-α, IFN-γ and IL-8 were measured in the cell culture supernatant using ELISA.

RESULTS

Treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL up-regulated IL-6, TNF-α, IFN-γ and IL-8 expression in human conjunctival epithelial cells. Following treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL, the culture supernatant of human conjunctival epithelial cells promoted neutrophil migration and induced increases in the staining intensity of MPO and CitH3. In addition, increased NETs triggered the apoptosis of human conjunctival epithelial cells and IL-6, TNF-α, IFN-γ and IL-8 secretion in the culture supernatant of human conjunctival epithelial cells.

CONCLUSIONS

CDM induces human conjunctival epithelial cell damages, thereby promoting neutrophil migration and NETs formation, while the release of NETs further aggravates human conjunctival epithelial cell damages.

Structural Basis for the Enhanced Infectivity and Immune Evasion of Omicron Subvariants

The Omicron variants of SARS-CoV-2 have emerged as the dominant strains worldwide, causing the COVID-19 pandemic. Each Omicron subvariant contains at least 30 mutations on the spike protein (S protein) compared to the original wild-type (WT) strain. Here we report the cryo-EM structures of the trimeric S proteins from the BA.1, BA.2, BA.3, and BA.4/BA.5 subvariants, with BA.4 and BA.5 sharing the same S protein mutations, each in complex with the surface receptor ACE2. All three receptor-binding domains of the S protein from BA.2 and BA.4/BA.5 are "up", while the BA.1 S protein has two "up" and one "down". The BA.3 S protein displays increased heterogeneity, with the majority in the all "up" RBD state. The different conformations preferences of the S protein are consistent with their varied transmissibility. By analyzing the position of the glycan modification on Asn343, which is located at the S309 epitopes, we have uncovered the underlying immune evasion mechanism of the Omicron subvariants. Our findings provide a molecular basis of high infectivity and immune evasion of Omicron subvariants, thereby offering insights into potential therapeutic interventions against SARS-CoV-2 variants.

Structural basis for the assembly of the DNA polymerase holoenzyme from a monkeypox virus variant

The ongoing global pandemic caused by a variant of the monkeypox (or mpox) virus (MPXV) has prompted widespread concern. The MPXV DNA polymerase holoenzyme, consisting of F8, A22, and E4, is vital for replicating the viral genome and represents a crucial target for the development of antiviral drugs. However, the assembly and working mechanism for the DNA polymerase holoenzyme of MPXV remains elusive. Here, we present the cryo-electron microscopy (cryo-EM) structure of the DNA polymerase holoenzyme at an overall resolution of 3.5 Å. Unexpectedly, the holoenzyme is assembled as a dimer of heterotrimers, of which the extra interface between the thumb domain of F8 and A22 shows a clash between A22 and substrate DNA, suggesting an autoinhibition state. Addition of exogenous double-stranded DNA shifts the hexamer into trimer exposing DNA binding sites, potentially representing a more active state. Our findings provide crucial steps toward developing targeted antiviral therapies for MPXV and related viruses.

[Efficacy and safety of neoadjuvant toripalimab combined with nimotuzumab and chemotherapy in patients with unresectable stage Ⅳ squamous cell carcinoma of penis]

Objective: To compare the efficacy and safety of neoadjuvant chemotherapy alone or combined with toripalimab and nimotuzumab in patients with unresectable locally advanced or metastatic squamous cell carcinoma of penis. Methods: A total of 33 patients with unresectable squamous cell carcinoma of penis undergoing neoadjuvant chemotherapy alone or combined with toripalimab and nimotuzumab at Sun Yat-sen University Cancer Center from May 2015 to June 2021 were enrolled retrospectively. All the patients were male, with a median age (M(IQR))of 49.0 (13.5) years (range: 30 to 70 years). According to the therapy protocols, patients were divided into the chemotherapy group (16 cases) and the triple combination group (17 cases). Log-rank test was used to compare the progression-free survival and overall survival. χ² test or Fisher exact method was used to compare the objective response rate, pathological down-stage rate and adverse events between these two groups. Results: The follow-up time was 28.1(19.2) months (range: 1.5 to 33.4 months). Patients of triple combination group were observed significantly longer progression-free survival (30.0 months vs. 8.2 months, χ²=3.998, P=0.046) than those of chemotherapy group. The median overall survival of the triple combination group and chemotherapy group were not reached and 15.2 months (χ²=3.298, P=0.069), respectively. Although there was no significant difference in the subsequent surgical resection rate between these two groups (12/17 vs.11/16, P=1), the objective response rate and the pathological complete response rate in triple combination group were significantly higher than in chemotherapy group (13/17 vs. 6/16, χ²=5.125, P=0.024; 6/7 vs. 0, P=0.001). The main common grade 1 to 2 adverse events in the triple combination group were alopecia (16 cases), anemia (15 cases), and nausea (14 cases). The main common grade 1 to 2 adverse events in the chemotherapy group were anemia (14 cases), alopecia (12 cases), decreased appetite (12 cases), and nausea (11 cases). The incidence of adverse events ≥grade 3 was similar in the triple combination group and chemotherapy group (8/17 vs. 6/16, χ²=0.308, P=0.579). There was no grade 3 adverse event in both groups. Conclusion: Compared with traditional chemotherapy alone, chemotherapy combined with toripalimab and nimotuzumab provides longer progression-free survival and similar toxicity for unresectable stage Ⅳ squamous cell carcinoma of penis.

[Impact of different obesity patterns on coronary microvascular function in male patients with non-obstructive coronary artery disease]

Objective: This study sought to investigate the impact of different obesity patterns on coronary microvascular function in male patients with non-obstructive coronary artery disease. Methods: We retrospectively analyzed clinical data of male patients diagnosed with suspected coronary microvascular dysfunction (CMD) in the First Hospital of Shanxi Medical University between December 2015 and August 2021. All patients underwent the one-day rest and stress ¹³N-ammonia positron emission tomography myocardial perfusion imaging. Overall obesity was defined by body mass index (BMI) ≥28 kg/m² and abdominal obesity was defined by waist circumference ≥90 cm. Hyperemic myocardial blood flow (MBF)<2.3 ml·min^-1·g^-1 or coronary flow reserve (CFR)<2.5 were referred as CMD. All patients were grouped based on their BMI and waist circumference. MBF, CFR, the incidence of CMD, hemodynamic parameters, and cardiac function were compared among the groups. Results: A total of 136 patients were included. According to BMI and waist circumference, patients were categorized into 3 groups: control group (n=45), simple abdominal obesity group (n=53) and compound obesity group (n=38). Resting MBF did not differ between groups (F=0.02,P=0.994). Compared with the control group, hyperemic MBF was significantly lower in the simple abdominal obesity and compound obesity groups ((2.82±0.64) ml·min^-1·g^-1, (2.44±0.85) ml·min^-1·g^-1 and (2.49±0.71) ml·min^-1·g^-1, both P<0.05, respectively). Hyperemic MBF was comparable among the groups of patients with obesity (P=0.772). CFR was significantly lower in the simle abdominal obesity group compared with the control group (2.87±0.99 vs. 3.32±0.62,P=0.012). Compared with the control group, CFR tended to be lower in the compound obesity group (3.02±0.91 vs. 3.32±0.62,P=0.117). The incidence of CMD was significantly higher in both the simple abdominal obesity and compound obesity groups than in the control group (62.3%, 52.6% vs. 22.2%, both P<0.01, respectively). Waist circumference was an independent risk factor for male CMD (OR=1.057, 95%CI: 1.013-1.103, P=0.011). Conclusions: In male patients with non-obstructive coronary artery disease, abdominal obesity is associated with decreased coronary microvascular function. Male patients with simple abdominal obesity face the highest risk of CMD.

[Willingness of receiving influenza vaccine and its influencing factors among health care workers in Yangtze River Delta region from 2020 to 2021]

Objective: To analyze the willingness of receiving influenza vaccine and its influencing factors among health care workers (HCWs) in Yangtze River Delta region from 2020 to 2021. Methods: Convenient sampling method was adopted. From July 2020 to March 2021, 76 hospitals in Jiangsu, Zhejiang, Anhui and Shanghai provinces were selected according to the hospital level and job position, and a questionnaire survey was conducted on the willingness of receiving influenza vaccination. Logistic regression model was used to analyze the influencing factors of vaccination intention. Results: A total of 1 332 HCWs were investigated, with a ratio of male to female about 1∶3.2, and the length of working years was (15.07±9.75) years. A total of 614 HCWs had received influenza vaccine in 2019, with a vaccination rate of 46.09%. About 63.21% (842/1 332) of HCWs were willing to be vaccinated with influenza vaccine. The results of binary logistic regression analysis showed that the willingness of receiving influenza vaccine among HCWs in primary hospitals was higher than that in secondary hospitals (OR=0.573) and tertiary hospitals (OR=0.357). The willingness of HCWs who had received influenza vaccine in 2019 was higher than that of HCWs who had not received influenza vaccine (OR=0.226) and had unknown history of influenza vaccination (OR=0.228). The willingness of HCWs in departments of prevention, health care and infection was higher than that in departments of pre-examination, outpatient, emergency, pediatrics and respiratory (OR=1.670). Conclusion: The willingness of receiving influenza vaccination among HCWs in Yangtze River Delta region is high, but it is still lower than that in developed countries. It is necessary to strengthen publicity and education to improve the influenza immunization level of HCWs.

A high-throughput fully automatic biosensing platform for efficient COVID-19 detection

We propose a label-free biosensor based on a porous silicon resonant microcavity and localized surface plasmon resonance. The biosensor detects SARS-CoV-2 antigen based on engineered trimeric angiotensin converting enzyme-2 binding protein, which is conserved across different variants. Robotic arms run the detection process including sample loading, incubation, sensor surface rinsing, and optical measurements using a portable spectrometer. Both the biosensor and the optical measurement system are readily scalable to accommodate testing a wide range of sample numbers. The limit of detection is 100 TCID_50/ml. The detection time is 5 min, and the throughput of one single robotic site is up to 384 specimens in 30 min. The measurement interface requires little training, has standard operation, and therefore is suitable for widespread use in rapid and onsite COVID-19 screening or surveillance.

Cryo-EM structures of recombinant human sodium-potassium pump determined in three different states

Sodium-Potassium Pump (Na⁺/K⁺-ATPase, NKA) is an ion pump that generates an electrochemical gradient of sodium and potassium ions across the plasma membrane by hydrolyzing ATP. During each Post-Albers cycle, NKA exchanges three cytoplasmic sodium ions for two extracellular potassium ions through alternating changes between the E1 and E2 states. Hitherto, several steps remained unknown during the complete working cycle of NKA. Here, we report cryo-electron microscopy (cryo-EM) structures of recombinant human NKA (hNKA) in three distinct states at 2.7–3.2 Å resolution, representing the E1·3Na and E1·3Na·ATP states with cytosolic gates open and the basic E2·[2K] state, respectively. This work provides the insights into the cytoplasmic Na⁺ entrance pathway and the mechanism of cytoplasmic gate closure coupled with ATP hydrolysis, filling crucial gaps in the structural elucidation of the Post-Albers cycle of NKA.

Sodium-Potassium Pump (Na⁺/K⁺-ATPase, NKA) generates an electrochemical gradient of sodium and potassium ions across the plasma membrane by hydrolyzing ATP. Here, the authors report structures of human NKA providing insight into the cytoplasmic Na⁺ entrance and the cytoplasmic gate closure coupled to ATP hydrolysis.

ACE2, B0AT1, and SARS-CoV-2 spike protein: Structural and functional implications

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emerged as a public health crisis and led to tremendous economic devastation. The spike protein (S) of SARS-CoV-2 hijacks the angiotensin converting enzyme 2 (ACE2) as a receptor for virus entry, representing the initial step of viral infection. S is one of the major targets for development of the antiviral drugs, antibodies, and vaccines. ACE2 is a peptidase that plays a physiologically important role in the renin-angiotensin system. Concurrently, it also forms dimer of heterodimer with the neutral amino acid transporter B⁰AT1 to regulate intestinal amino acid metabolism. The symptoms of COVID-19 are closely correlated with the physiological functions of ACE2. In this review, we summarize the functional and structural studies on ACE2, B⁰AT1, and their complex with S of SARS-CoV-2, providing insights into the various symptoms caused by viral infection and the development of therapeutic strategies.

Knowledge and attitudes toward repetitive transcranial magnetic stimulation (rTMS) as a treatment for postpartum and peripartum depression

Introduction

Postpartum and peripartum depression are debilitating disorders that impact the mother and their ability to care for their children’s emotional, social, and physical needs. Current treatments include psychotherapy, pharmacotherapy, and electroconvulsive therapy. These treatments are moderately effective or come with side effects that can negatively impact mother and child. As a result, many mothers view some treatments as unacceptable while pregnant or breastfeeding. Over the last decade, repetitive transcranial magnetic stimulation (rTMS) has shown promise as an effective and safe treatment option for postpartum and peripartum depression. However, little is known regarding people’s knowledge and attitudes towards this emerging technology, with no research assessing this in Canada.

Objectives

We aim to identify gaps in knowledge and to assess attitudes toward rTMS as a treatment for postpartum and peripartum depression in mental health professionals, patients, and the general public living in Canada.

Methods

A mixed methods study design will be employed. The qualitative portion will consist of individual semi-structured interviews. An inductive thematic analysis will be completed. The quantitative portion will consist of an anonymous, self-administered survey shared through REDCap. Focus groups with rTMS experts will be conducted to inform survey creation.

Results

No resulst at this time.

Conclusions

Understanding gaps in knowledge and attitudes toward rTMS is the first step toward ensuring that everyone is well informed and able to access safe and effective treatments. With limited treatment options available to a postpartum and/or peripartum depression patients being well informed on all treatments is crucial towards accessing treatments that best suit their needs.

Disclosure

No significant relationships.

[Advances in research of interchangeable immunization with live attenuated Japanese encephalitis vaccines and inactivated vaccines]

Japanese encephalitis (JE) virus is the leading cause of vaccine-preventable encephalitis in Asia and the Western Pacific, which mainly invades central nervous system. Vaccination is the most important strategy to prevent JE. Currently, both live attenuated Japanese encephalitis vaccines (JE-L) and inactivated vaccines (JE-I) are in use. Due to the supply of vaccines and the personal choice of recipients, there will be a demand for interchangeable immunization of these two vaccines. However, relevant research is limited. By reviewing domestic and foreign research evidence, this article summarizes the current situation of the interchangeable use of JE-L and JE-I, and makes recommendations when the interchangeable immunization is in urgent need, so as to provide reference for practical vaccination and policymaking in China.

[Epidemiological characteristics and spatiotemporal clustering of hepatitis A in Zhejiang Province from 2010 to 2019]

Objective: To analyze the epidemiological characteristics and spatiotemporal clustering of hepatitis A in Zhejiang Province from 2010 to 2019. Methods: The data of hepatitis A incidence in Zhejiang Province from 2010 to 2019 were collected from the infectious disease surveillance system of China Information System for Disease Control and Prevention. ArcGIS 10.7 software was used for spatial autocorrelation analysis. SaTScan 9.6 software was used for spatiotemporal scanning analysis. SPSS 25.0 software was used for additional analysis. Results: Zhejiang Province has reported 5 465 cases of hepatitis A in 2010-2019 years, with an average annual incidence rate of 1.00/100 000, and periodicity and seasonality are not obvious. The incidence of male was higher than that of female (P=0.023), and the highest incidence rate was 50-59 years old. Spatial autocorrelation analysis showed that there was a positive spatial correlation between the incidence of hepatitis A in Zhejiang Province from 2010 to 2017, with the weakest correlation in 2010 (Moran's I =0.103, Z=1.769, P=0.049), and the strongest correlation in 2016 (Moran's I=0.328, Z=4.979, P=0.001). Spatiotemporal scanning analysis showed that there was spatial aggregation of hepatitis A in Zhejiang Province from 2010 to 2019, with a total of three aggregation areas identified. Among them, the mostly aggregation area was concentrated in Xiangshan county of Ningbo city, which covered 10 counties (cities and districts), including Ninghai county and Yinzhou district, and appeared from January 1 to June 30, 2012. Conclusion: The incidence level of hepatitis A in Zhejiang Province shows a stable fluctuation trend from 2010 to 2019, and the seasonal regularity is not obvious. The population group aged 50-59 years old is the key population. There is spatial aggregation in the epidemic situation of hepatitis A. Targeted prevention and control measures of hepatitis A should be done based on the law of spatiotemporal aggregation and local incidence.

[Evaluating the real-world vaccine effectiveness using a regression discontinuity design]

Estimating the actual real-world effectiveness of the vaccine is an essential part of the post-marketing evaluation. This regression discontinuity design (RDD) using observational data is designed to quantify the effect of an intervention when eligibility for the intervention is based on a defined cutoff as age, making it suited to estimate vaccine effects. This approach can avoid the high cost and ethical issues; overcome difficulties in the organization and practice process in randomized controlled trials, which leads to a higher level of causal inference evidence and more realistic results. Here, we describe key features of RDD in general, and then specific scenarios, with examples, to illustrate that RDD are an essential tool for advancing our understanding of vaccine effects.

Structural advances in sterol-sensing domain-containing proteins

The sterol-sensing domain (SSD) is present in several membrane proteins that function in cholesterol metabolism, transport, and signaling. Recent progress in structural studies of SSD-containing proteins, such as sterol regulatory element-binding protein (SREBP)-cleavage activating protein (Scap), Patched, Niemann-Pick disease type C1 (NPC1), and related proteins, reveals a conserved core that is essential for their sterol-dependent functions. This domain, by its name, 'senses' the presence of sterol substrates through interactions and may modulate protein behaviors with changing sterol levels. We summarize recent advances in structural and mechanistic investigations of these proteins and propose to divide them to two classes: M for 'moderator' proteins that regulate sterol metabolism in response to membrane sterol levels, and T for 'transporter' proteins that harbor inner tunnels for cargo trafficking across cellular membranes.

ACE2-targeting monoclonal antibody as potent and broad-spectrum coronavirus blocker

The evolution of coronaviruses, such as SARS-CoV-2, makes broad-spectrum coronavirus preventional or therapeutical strategies highly sought after. Here we report a human angiotensin-converting enzyme 2 (ACE2)-targeting monoclonal antibody, 3E8, blocked the S1-subunits and pseudo-typed virus constructs from multiple coronaviruses including SARS-CoV-2, SARS-CoV-2 mutant variants (SARS-CoV-2-D614G, B.1.1.7, B.1.351, B.1.617.1, and P.1), SARS-CoV and HCoV-NL63, without markedly affecting the physiological activities of ACE2 or causing severe toxicity in ACE2 “knock-in” mice. 3E8 also blocked live SARS-CoV-2 infection in vitro and in a prophylactic mouse model of COVID-19. Cryo-EM and “alanine walk” studies revealed the key binding residues on ACE2 interacting with the CDR3 domain of 3E8 heavy chain. Although full evaluation of safety in non-human primates is necessary before clinical development of 3E8, we provided a potentially potent and “broad-spectrum” management strategy against all coronaviruses that utilize ACE2 as entry receptors and disclosed an anti-coronavirus epitope on human ACE2.

SARS-CoV-2 exacerbates proinflammatory responses in myeloid cells through C-type lectin receptors and Tweety family member 2

Despite mounting evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) engagement with immune cells, most express little, if any, of the canonical receptor of SARS-CoV-2, angiotensin-converting enzyme 2 (ACE2). Here, using a myeloid cell receptor-focused ectopic expression screen, we identified several C-type lectins (DC-SIGN, L-SIGN, LSECtin, ASGR1, and CLEC10A) and Tweety family member 2 (TTYH2) as glycan-dependent binding partners of the SARS-CoV-2 spike. Except for TTYH2, these molecules primarily interacted with spike via regions outside of the receptor-binding domain. Single-cell RNA sequencing analysis of pulmonary cells from individuals with coronavirus disease 2019 (COVID-19) indicated predominant expression of these molecules on myeloid cells. Although these receptors do not support active replication of SARS-CoV-2, their engagement with the virus induced robust proinflammatory responses in myeloid cells that correlated with COVID-19 severity. We also generated a bispecific anti-spike nanobody that not only blocked ACE2-mediated infection but also the myeloid receptor-mediated proinflammatory responses. Our findings suggest that SARS-CoV-2-myeloid receptor interactions promote immune hyperactivation, which represents potential targets for COVID-19 therapy.

Measurements of neutral particle energy spectrum on EAST using a time-of-flight low-energy neutral particle analyzer

The neutral particles generated by charge exchange reactions can play an important role in erosion of first wall materials in fusion devices. In order to measure the flux and energy of neutral particles to the first wall, a low-energy neutral particle analyzer (LENPA) based on the time-of-flight method has been developed and successfully applied on the Experimental Advanced Superconducting Tokamak (EAST)' to measure the neutrals with an energy of 20-3000 eV. The LENPA works in the counting mode, and the signal of photons is used as the reference for the flight time of neutrals. The energy spectrum of low-energy neutral particles on EAST has been obtained for the first time. The new diagnostics can help in understanding the neutral particle generation and deposition on the first wall materials in tokamaks under different plasma conditions.

POS1128 COMBINATION TREATMENT OF AR882, A NEW URAT1 INHIBITOR, AND XANTHINE OXIDASE INHIBITORS ALLOPURINOL OR FEBUXOSTAT: EFFECT ON URIC ACID, HYPOXANTHINE AND XANTHINE IN PLASMA OR SERUM AND URINE

Background:

Xanthine oxidase inhibitors (XOI) are commonly used as urate lowering therapy (ULT) for the treatment of gout. Allopurinol, the first-line treatment, demonstrates low response rate (< 40%), defined as serum urate (sUA) lowering effect below 6 mg/dL, in multiple large-scale clinical trials. As recommended in EULAR guidelines and other literatures, targeting sUA <5 mg/dL or even <4 mg/dL, provides a better opportunity to lower incidence of gout flare and resolution of tophi in gout patients. Febuxostat, a more potent XOI, has been classified as a second-line ULT agent due to increased cardiovascular risks in certain patient populations. For XOI intolerance and non-responders, replacing the agent with a potent URAT1 inhibitor or adding an URAT1 inhibitor onto a current treatment regimen provides opportunities to improve response rates in patients with refractory gout. AR882 is a uricosuric agent that blocks the reabsorption of uric acid in the apical side of renal tubule, hence increases excretion of uric acid into the urine. A phase 2a study has demonstrated the additive effects of AR882 in combination with allopurinol or febuxostat.

Objectives:

To evaluate the effect of AR882 alone or in combination with allopurinol or febuxostat on circulating levels and urinary excretion of hypoxanthine, xanthine and uric acid. Furthermore, to elucidate the contribution of each drug towards the combination effect in sUA lowering.

Methods:

Plasma, serum, and urine samples were collected from 17 patients with gout who received a once-daily dosing of AR882 50 mg, allopurinol 300 mg or febuxostat 40 mg, or in combination for one week in a phase 2a study. Samples were collected to measure hypoxanthine, xanthine and uric acid levels in plasma or serum and the amount of each excreted in the urine. Plasma Cmax and AUC and 24-hour urine excretion amount (mg) of hypoxanthine and xanthine were calculated by non-compartmental analysis method.

Results:

In monotherapy, AR882 demonstrated better sUA lowering effect (↓53%) compared to allopurinol (↓35%) or febuxostat (↓39%). Combination of AR882 and allopurinol lowered sUA by 66% while combination of AR882 and febuxostat lowered sUA by 71%. Based on the change of xanthine in plasma following combination treatments, it can be calculated that allopurinol contributed 28% of the urate lowering effect, whereas AR882 contributed 38% of the effect. Similarly, febuxostat contributed 33% of the urate lowering effect and AR882 contributed to about 36-38% of the effect when used in combination. The combination treatments significantly increased the response ratio for patients achieving sUA levels < 5 mg/dL, 4 mg/dL, and even 3 mg/dL. In the combination with allopurinol, 100%, 100%, 100%, and 44% patients achieved sUA < 6 mg/dL, < 5 mg/dL, 4 mg/dL, and 3 mg/dL, respectively. Similar results were seen with the combination of AR882 and febuxostat. Treatment with allopurinol or febuxostat alone resulted in 8 to 10-fold and 16-fold increases of xanthine exposure, respectively. The combination of AR882 and allopurinol or febuxostat showed approximately 5-8 fold or 13-fold increases in plasma xanthine, respectively. Treatment with allopurinol or febuxostat alone resulted in 2-3 fold increase in hypoxanthine exposure. Relative changes of hypoxanthine were not significantly different in the presence versus absence of AR882. Increased excretion of xanthine and hypoxanthine was also observed in urine. AR882 was well tolerated in gout patients, showing a similar safety profile to that observed in healthy volunteer studies.

Conclusion:

AR882 dose alone had no effect on plasma or urine hypoxanthine and xanthine levels. AR882 contributed to a greater portion of the serum urate lowering effects when used in combination with XO inhibitors, and with 100% of patients achieving levels below 4 mg/dL when combined with allopurinol. The use of AR882 in combination with XO inhibitors may provide an option for preventing flares as well as tophi reduction in advanced patients.

Disclosure of Interests:

Zancong Shen Employee of: arthrosi therapeutics, Chris Colton Employee of: Arthrosi therapeutics Inc, Rongzi Yan Employee of: Arthrosi therapeutics Inc, Elizabeth Polvent Employee of: Arthrosi therapeutics Inc, Vijay Hingorani Consultant of: Arthrosi therapeutics Inc, Shunqi Yan Employee of: Arthrosi therapeutics Inc, Li-Tain Yeh Employee of: Arthrosi therapeutics Inc.

POS1130 PHARMACOKINETICS AND SERUM URATE LOWERING EFFECTS OF AR882, A NOVEL, POTENT AND SELECTIVE URICOSURIC AGENT, IN PATIENTS WITH GOUT

Background:

AR882 is a novel, potent and selective uric acid transporter 1 (URAT1) inhibitor in Phase 2 development for the treatment of hyperuricemia and gout. In Phase 1 healthy subject studies, AR882 demonstrated good dose proportionality, a long effective half-life and sustained serum urate (sUA) lowering effects, consequently making it suitable for once-daily dosing. In addition, AR882 was well tolerated following single and multiple dosing.

Objectives:

This Phase 2a study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and safety of AR882 following monotherapy in patients with gout. PK and sUA lowering effects in patients with renal impairment and normal renal function were also compared.

Methods:

A total of 30 adults with gout (sUA >7 mg/dL) were enrolled and 28 had post-baseline PKPD assessments performed. AR882 was administered at escalating doses of 25, 50 and 75 mg, with each dose administered once daily for 7 days. Serial blood samples were collected to measure AR882 PK and sUA levels at the end of each treatment week. Urine samples were collected for assessment of uric acid excretion. Laboratory safety tests, vital signs, and electrocardiograms were collected throughout the study.

Results:

Following once daily administration in patients with gout, AR882 exposures increased dose proportionally between 25 and 75 mg. Mean sUA levels were maximally reduced from baseline (mean 8.9 mg/dL) to 5.6, 4.2 and 3.2 mg/dL at the 25-, 50- and 75-mg dose levels, respectively. The corresponding percent reductions were 36.8%, 52.7% and 61.5%. The effects were sustained throughout the entire dosing day with minimal fluctuation. In patients receiving 25 mg AR882 (N=9), 56% achieved sUA levels below 6 mg/dL. At 50 mg (N=28), 96% of patients had sUA levels below 6 mg/dL and 93% were below 5 mg/dL. At the 75 mg dose (N=8), all patients (100%) achieved levels below 5 mg/dL, and 88% were below 4 mg/dL. Among these 28 gout patients, 17 patients had normal renal function (CrCL>90 mL/min) and 11 patients had mild impairment (CrCL 60-90 mL/min). AR882 exposures were similar between patients with mild renal impairment and those with normal renal function. Both groups showed nearly identical sUA lowering effects following each 7-day dosing period. Response rates were also similar between these groups, including at the 50 and 75 mg dose levels. Consistent with its sUA lowering effects, dose-dependent increases in fractional excretion of uric acid were observed across all doses.

AR882 was well tolerated at all doses tested. All AEs were mild or moderate in severity and most were considered not related to study treatment. There were no serious AEs or AEs resulting in study drug discontinuation. There were no clinically significant laboratory or ECG abnormalities noted.

Conclusion:

In patients with gout, AR882 exhibited dose proportional increases in plasma exposure and dose-dependent reductions in sUA. Nearly all patients had sUA levels below 5 mg/dL at doses ≥50 mg, and about 90% of patients had sUA levels <4 mg/dL at 75 mg dosing. Similar PK exposures and sUA lowering effects were observed in patients with mild renal impairment compared to those with normal renal function. Current data suggest that AR882 50 mg may offer improved efficacy over existing standard-of-care for gout and AR882 75 mg may have utility in the treatment of patients with severe or refractory gout disease.

Figure 1.

Percent of Patients with sUA below 6 mg/dL, 5 mg/dL, 4 mg/dL or 3 mg/dL Following Once-Daily Oral Doses of AR882.

Table 1.

Mean (SD) sUA Levels Following Once-Daily Oral Doses of AR882.

TreatmentNTime (hr), sUA (mg/dL)061224Baseline308.8 (1.1)8.8 (1.1)9.0 (1.0)8.9 (1.1)25 mg96.1 (0.4)5.6 (0.4)5.6 (0.3)5.8 (0.4)50 mg284.7 (0.9)4.2 (0.9)4.3 (0.8)4.7 (1.0)75 mg83.7 (1.1)3.2 (0.9)3.2 (0.8)3.6 (1.0)50 mg (normal renal function)174.8 (1.1)4.3 (1.1)4.4 (0.9)4.8 (1.2)50 mg (mild impairment)114.5 (0.6)4.1 (0.6)4.3 (0.5)4.6 (0.6)

Disclosure of Interests:

Zancong Shen Employee of: Arthrosi Therapeutics Inc, Elizabeth Polvent Employee of: Arthrosi Therapeutics Inc, Vijay Hingorani Consultant of: Arthrosi Therapeutics Inc, Andrea Clouser Roche Employee of: Arthrosi Therapeutics Inc, Chris Colton Employee of: Arthrosi Therapeutics Inc, Rongzi Yan Employee of: Arthrosi Therapeutics Inc, Shunqi Yan Employee of: Arthrosi Therapeutics Inc, Li-Tain Yeh Employee of: Arthrosi Therapeutics Inc.

Structural basis for sterol sensing by Scap and Insig

The sterol regulatory element-binding protein (SREBP) pathway monitors the cellular cholesterol level through sterol-regulated association between the SREBP cleavage-activating protein (Scap) and the insulin-induced gene (Insig). Despite structural determination of the Scap and Insig-2 complex bound to 25-hydroxycholesterol, the luminal domains of Scap remain unresolved. In this study, combining cryogenic electron microscopy (cryo-EM) analysis and artificial intelligence-facilitated structural prediction, we report the structure of the human Scap/Insig-2 complex purified in digitonin. The luminal domain loop 1 and a co-folded segment in loop 7 of Scap resemble those of the luminal/extracellular domain in NPC1 and related proteins, providing clues to the cholesterol-regulated interaction of loop 1 and loop 7. An additional luminal interface is observed between Scap and Insig. We also show that Scap(D428A), which inhibits SREBP activation even under sterol depletion, exhibits an identical conformation with the wild-type protein when complexed with Insig-2, and its constitutive suppression of the SREBP pathway may also involve a later step in protein trafficking.

[Amiodarone promotes heat-induced apoptosis, inflammation and oxidative stress in mouse HL1 atrial myocytes]

OBJECTIVE

To investigate the injury types of atrial myocytes induced by heat exposure and the effect of amiodarone on heat-induced injuries in atrial myocytes.

OBJECTIVE

The optimal temperature for heat exposure and optimal concentration of amiodarone were determined by measuring the cell viability exposed to different temperatures and different concentrations of amiodarone. Heat exposure of HL1 atrial myocytes was conducted using a water bath, and the effect of amiodarone on cell viability was assessed with MTS method; cell apoptosis was detected using flow cytometry, and the levels of IL-1β, IL-6, TNF-α, SOD and MDA were detected with enzyme-linked immunosorbent assay (ELISA).

OBJECTIVE

Compared with the blank control cells, the cells exposed to a temperature of 52 ℃ showed a significantly decreased survival rate and a lowered SOD activity (P < 0.001) with increased IL-1β and MDA levels (P < 0.01) and markedly increased apoptosis rate and IL-6 level (P < 0.001). Compared with the heat exposure group, amiodarone resulted in significantly decreased survival rate of the atrial myocytes (P < 0.01), obviously decreased SOD activity (P < 0.05), and increased cell apoptosis rate (P < 0.05) and IL-1β, IL-6, MDA and TNF-α levels (P < 0.01 or 0.001).

OBJECTIVE

Heat exposure induces apoptosis, inflammation and oxidative stress in mouse HL1 atrial myocytes, and amiodarone can enhance the effects of heat exposure to aggravate the cell injuries.

Mechanism of substrate transport and inhibition of the human LAT1-4F2hc amino acid transporter

LAT1 (SLC7A5) is one of the representative light chain proteins of heteromeric amino acid transporters, forming a heterodimer with its heavy chain partner 4F2hc (SLC3A2). LAT1 is overexpressed in many types of tumors and mediates the transfer of drugs and hormones across the blood-brain barrier. Thus, LAT1 is considered as a drug target for cancer treatment and may be exploited for drug delivery into the brain. Here, we synthesized three potent inhibitors of human LAT1, which inhibit transport of leucine with IC₅₀ values between 100 and 250 nM, and solved the cryo-EM structures of the corresponding LAT1-4F2hc complexes with these inhibitors bound at resolution of up to 2.7 or 2.8 Å. The protein assumes an outward-facing occluded conformation, with the inhibitors bound in the classical substrate binding pocket, but with their tails wedged between the substrate binding site and TM10 of LAT1. We also solved the complex structure of LAT1-4F2hc with 3,5-diiodo-l-tyrosine (Diiodo-Tyr) at 3.4 Å overall resolution, which revealed a different inhibition mechanism and might represent an intermediate conformation between the outward-facing occluded state mentioned above and the outward-open state. To our knowledge, this is the first time that the outward-facing conformation is revealed for the HAT family. Our results unveil more important insights into the working mechanisms of HATs and provide a structural basis for future drug design.

The biological characters of Bmelav-like genes in the development of Bombyx mori

The ELAV/Hu family is a conserved multigene family of pan-neuronal RNA-binding protein involved in post-transcriptional regulation in metazoans. In Drosophila, three members of this family, ELAV, RBP9 and FNE, are involved in neuronal differentiation, gene expression regulation and so on. This family is less well characterized in Bombyx mori. Two orthologs BmELAV-like-1 (BmEL-1) and BmELAV-like-2 (BmEL-2) share 55%-71% and 47%-62% identity with that of in Drosophila and humans, respectively. Bmel-1 is ubiquitously expressed while Bmel-2 is expressed in the head and ovaries specifically. Proteins encoded by both genes are localized in nuclear and cytoplasm. The weight of body, cocoon, pupae and cocoon shell are differently affected in Bmel-1^- /-2^- mutants created using CRISPR/Cas9 technology. Mutations of both genes increase the expression of four silk protein genes, Fib-L, Fib-H, P25 and Ser-1. In addition, the oviposition ability of Bmel-2^- females is decreased. This study not only provides valuable insights into the functional roles of Bmelav-like genes in the growth, cocoon characters and regulation of silk protein genes expression, but also provides useful information for silkworm variety breeding.

A structure of human Scap bound to Insig-2 suggests how their interaction is regulated by sterols

The sterol regulatory element-binding protein (SREBP) pathway controls cellular homeostasis of sterols. The key players in this pathway, Scap and Insig-1 and -2, are membrane-embedded sterol sensors. The 25-hydroxycholesterol (25HC)-dependent association of Scap and Insig acts as the master switch for the SREBP pathway. Here, we present cryo-electron microscopy analysis of the human Scap and Insig-2 complex in the presence of 25HC, with the transmembrane (TM) domains determined at an average resolution of 3.7 angstrom. The sterol-sensing domain in Scap and all six TMs in Insig-2 were resolved. A 25HC molecule is sandwiched between the S4 to S6 segments in Scap and TMs 3 and 4 in Insig-2 in the luminal leaflet of the membrane. Unwinding of the middle of the Scap-S4 segment is crucial for 25HC binding and Insig association.

[A preliminary study on the mixed teaching of human parasitology based on MOOC resources and the experimental teaching digital platform]

The mixed teaching model combines the advantages of traditional teaching and network teaching in the "Internet +" era, which has become one of the important trends in the higher education teaching development. In order to follow this development trend, the human parasitology teaching team makes a reasonable use of modern information techniques, actively promotes the construction and application of online resources, and conducts mixed online and offline teaching based on MOOC resources and the experimental teaching digital platform. This mixed teaching model has shown a positive impact on both teaching and learning among teachers and students; however, students' personalized independent and deep learning remains unsatisfactory. It is suggested that the online course resources construction, teaching design and digital literacy remain to be increased, so as to create a high-level, innovative and challenging online-offline mixed "golden course".

MicroRNA-338-3p inhibits the progression of bladder cancer through regulating ETS1 expression

OBJECTIVE

MicroRNA-338-3p (miR-338-3p) was reported to influence the metastasis and development of several human cancers. However, in bladder cancer (BC), the special function of miR-338-3p remains unknown. Here, we aimed at exploring the miR-338-3p function in the progression of BC.

PATIENTS AND METHODS

miR-338-3p and ETS1 expressions were examined by quantitative Real-time polymerase chain reaction (qRT-PCR) in BC samples. Following that, transwell assays for cell migration and invasion were performed. And MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay for cell proliferation was conducted as well. Western blot was employed to examine the epithelial-mesenchymal transition (EMT) marker expressions. Finally, the relationship between miR-338-3p and E26 transformation specific-1 (ETS1) was verified by luciferase reporter assay.

RESULTS

The decreased miR-338-3p expression was examined in BC cells. Moreover, miR-338-3p upregulation repressed cell proliferation ability in BC. Next, miR-338-3p upregulation also depressed cell metastasis and EMT in BC cells. Furthermore, ETS1 was a direct target of miR-338-3p and inversely associated with its expression. And upregulation of ETS1 partially rescued the suppression of miR-338-3p for cell proliferation and metastasis in BC.

CONCLUSIONS

Upregulation of miR-338-3p inhibited the proliferation, metastasis and EMT in BC by suppressing ETS, showing that miR-338-3p might block the development of BC through regulating ETS1 expression.

Cogeneration of hot electrons from multiple laser-plasma instabilities

Interactions of two-plasmon decay (TPD) and side-stimulated Raman scattering (SSRS) were studied using three-dimensional particle-in-cell simulations under inertial-confinement-fusion-relevant conditions for linearly and circularly polarized lasers. In the linear stage, SSRS took place under n_{e}=0.235n_{c} and TPD dominated near the quarter-critical density surface and their growth rates agreed with theory. In the nonlinear stage, SSRS reduced TPD through pump depletion. Hot electrons were found to be first accelerated by SSRS plasma waves and then by TPD plasma waves through a cogeneration mechanism. Compared to the linearly polarized case with the same laser intensity, both SSRS and TPD were reduced due to the lower laser amplitude in the circularly polarized case. As a result, a 30% decrease in hot electron flux was observed.

A neutralizing human antibody binds to the N-terminal domain of the Spike protein of SARS-CoV-2

A key target for therapeutic antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the spike protein, a trimeric protein complex with each monomer comprising an S1 and an S2 domain that mediate binding to host cells and membrane fusion, respectively. In addition to the receptor binding domain (RBD), S1 has an N-terminal domain (NTD). In searching for neutralizing antibodies, there has been a focus on the RBD. Chi et al. isolated antibodies from 10 convalescent patients and identified an antibody that potently neutralizes the virus but does not bind the RBD. Cryo–electron microscopy revealed the epitope as the NTD. This NTD-targeting antibody may be useful to combine with RBD-targeting antibodies in therapeutic cocktails.

Science, this issue p. 650

Developing therapeutics against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could be guided by the distribution of epitopes, not only on the receptor binding domain (RBD) of the Spike (S) protein but also across the full Spike (S) protein. We isolated and characterized monoclonal antibodies (mAbs) from 10 convalescent COVID-19 patients. Three mAbs showed neutralizing activities against authentic SARS-CoV-2. One mAb, named 4A8, exhibits high neutralization potency against both authentic and pseudotyped SARS-CoV-2 but does not bind the RBD. We defined the epitope of 4A8 as the N-terminal domain (NTD) of the S protein by determining with cryo–eletron microscopy its structure in complex with the S protein to an overall resolution of 3.1 angstroms and local resolution of 3.3 angstroms for the 4A8-NTD interface. This points to the NTD as a promising target for therapeutic mAbs against COVID-19.

Cryo-EM structure of the human heteromeric amino acid transporter b0,+AT-rBAT

Heteromeric amino acid transporters (HATs) catalyze the transmembrane movement of amino acids, comprising two subunits, a heavy chain and a light chain, linked by a disulfide bridge. The b^0,+AT (SLC7A9) is a representative light chain of HATs, forming heterodimer with rBAT, a heavy chain which mediates the membrane trafficking of b^0,+AT. The b^0,+AT-rBAT complex is an obligatory exchanger, which mediates the influx of cystine and cationic amino acids and the efflux of neutral amino acids in kidney and small intestine. Here, we report the cryo-EM structure of the human b^0,+AT-rBAT complex alone and in complex with arginine substrate at resolution of 2.7 and 2.3 Å, respectively. The overall structure of b^0,+AT-rBAT exists as a dimer of heterodimer consistent with the previous study. A ligand molecule is bound to the substrate binding pocket, near which an occluded pocket is identified, to which we found that it is important for substrate transport.