Machine learning predicts the serum PFOA and PFOS levels in pregnant women: Enhancement of fatty acid status on model performance.

Human exposure to per- and polyfluoroalkyl substances (PFASs) has received considerable attention, particularly in pregnant women because of their dramatic changes in physiological status and dietary patterns. Predicting internal PFAS exposure in pregnant women, based on external and relevant parameters, has not been investigated. Here, machine learning (ML) models were developed to predict the serum concentrations of PFOA and PFOS in a large population of 588 pregnant participants. Dietary exposure characteristics, demographic parameters, and in particular, serum fatty acid (FA) data were used for the model development. The fitting results showed that the inclusion of FAs as covariates significantly improved the performance of the ML models, with the random forest (RF) model having the best predictive performance for PFOA (R2 = 0.33, MAE = 1.51 ng/mL, and RMSE = 1.89 ng/mL) and PFOS (R2 = 0.12, MAE = 2.65 ng/mL, and RMSE = 3.37 ng/mL). The feature importance analysis revealed that serum FAs greatly affected PFOA concentration in the pregnant women, with saturated FAs being associated with decreased PFOA levels and unsaturated FAs with increased levels. Comparison with one-compartment pharmacokinetic model further demonstrated the advantage of the ML models in predicting PFAS exposure in pregnant women. Our models correlate for the first time blood chemical concentrations with human FA status using ML, introducing a novel perspective on predicting PFAS levels in pregnant women. This study provides valuable insights concerning internal exposure of PFASs generated from external exposure, and contributes to risk assessment and management in pregnant populations.

Long-Term Erythromycin Treatment Alters the Airway and Gut Microbiota: Data from Chronic Obstructive Pulmonary Disease Patients and Mice with Emphysema.

INTRODUCTION: Although long-term macrolide antibiotics could reduce the recurrent exacerbation of chronic obstructive pulmonary disease (COPD), the side effect of bacterial resistance and the impact on the microbiota remain concerning. We investigated the influence of long-term erythromycin treatment on the airway and gut microbiota in mice with emphysema and patients with COPD. METHODS: We conducted 16S rRNA gene sequencing to explore the effect of erythromycin treatment on the lung and gut microbiota in mice with emphysema. Liquid chromatography-mass spectrometry was used for lung metabolomics. A randomized controlled trial was performed to investigate the effect of 48-week erythromycin treatment on the airway and gut microbiota in COPD patients. RESULTS: The mouse lung and gut microbiota were disrupted after cigarette smoke exposure. Erythromycin treatment depleted harmful bacteria and altered lung metabolism. Erythromycin treatment did not alter airway or gut microbial diversity in COPD patients. It reduced the abundance of pathogens, such as Burkholderia, in the airway of COPD patients and increased levels of symbiotic bacteria, such as Prevotella and Veillonella. The proportions of Blautia, Ruminococcus, and Lachnospiraceae in the gut were increased in COPD patients after erythromycin treatment. The time to the first exacerbation following treatment was significantly longer in the erythromycin treatment group than in the COPD group. CONCLUSION: Long-term erythromycin treatment reduces airway and gut microbe abundance in COPD patients but does not affect microbial diversity and restores microbiota balance in COPD patients by reducing the abundance of pathogenic bacteria.

PFASs in Cerebrospinal Fluids and Blood-CSF Barrier Permeability in Patients with Cognitive Impairment.

Attention has been drawn to the associations between PFASs and human cognitive decline. However, knowledge on the occurrence and permeability of PFASs in the brains of patients with cognitive impairment has not been reported. Here, we determined 30 PFASs in paired sera and cerebrospinal fluids (CSFs) from patients with cognitive impairment (n = 41) and controls without cognitive decline (n = 18). We revealed similar serum PFAS levels but different CSF PFAS levels, with lower CSF PFOA (median: 0.125 vs 0.303 ng/mL, p < 0.05), yet higher CSF PFOS (0.100 vs 0.052 ng/mL, p < 0.05) in patients than in controls. Blood-brain transfer rates also showed lower RCSF/Serum values for PFOA and higher RCSF/Serum values for PFOS in patients, implying potential heterogeneous associations with cognitive function. The RCSF/Serum values for C4-C14 perfluoroalkyl carboxylates exhibited a U-shape trend with increasing chain length. Logistic regression analyses demonstrated that CSF PFOS levels were linked to the heightened risk of cognitive impairment [odds ratio: 3.22 (1.18-11.8)] but not for serum PFOS. Toxicity inference results based on the Comparative Toxicogenomics Database suggested that PFOS in CSF may have a greater potential to impair human cognition than other PFASs. Our results contribute to a better understanding of brain PFAS exposure and its potential impact on cognitive function.

Long-term Radiological and Pulmonary Function Abnormalities at 3-year post COVID-19 Hospitalization: A Longitudinal Cohort Study.

BACKGROUND: This study aimed to evaluate the longitudinal progression of residual lung abnormalities (ground-glass opacities, reticulations, and fibrotic-like changes) and pulmonary function, three years following coronavirus disease 2019(COVID-19). METHODS: This prospective, longitudinal cohort study enrolled COVID-19 survivors who exhibited residual lung abnormalities upon discharge from two hospitals. Follow-up assessments were conducted at 6 months, 12 months, 2 years, and 3 years post-discharge, and included pulmonary function tests, 6-minute walk distance (6MWD), chest CT scans, and symptom questionnaires. Non-COVID-19 controls were retrospectively recruited for comparative analysis. RESULTS: 728 COVID-19 survivors and 792 controls were included. From 6 months to 3 years, there was a gradual improvement in reduced diffusing capacity of the lungs for carbon monoxide (DLCO＜80% predicted, 49% versus 38%, p=0.001), 6MWD (496 m versus 510 m, p=0.002) and residual lung abnormalities(46% versus 36%, p<0.001), regardless of the disease severity. Patients with residual lung abnormalities at 3 years more commonly had respiratory symptoms (32% versus 16%, p<0.001), lower 6MWD (494 m versus 510 m, p=0.003), and abnormal DLCO (57% versus 27%, p<0.001) compared to those with complete resolution. Compared to the controls, the proportion of DLCO impairment (38% versus 17%, p<0.001) and respiratory symptoms (23% versus 2.2%, p<0.001) were significantly higher in the matched COVID-19 survivors at the 3-year follow-up. CONCLUSIONS: Most patients exhibited improvement in radiological abnormalities and pulmonary function over time following COVID-19. However, more than one-third continued to have persistent lung abnormalities at the 3-year mark, which were associated with respiratory symptoms and reduced diffusion capacity.

Development of a bispecific nanobody conjugate broadly neutralizes diverse SARS-CoV-2 variants and structural basis for its broad neutralization.

The continuous emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility and profound immune-escape capacity makes it an urgent need to develop broad-spectrum therapeutics. Nanobodies have recently attracted extensive attentions due to their excellent biochemical and binding properties. Here, we report two high-affinity nanobodies (Nb-015 and Nb-021) that target non-overlapping epitopes in SARS-CoV-2 S-RBD. Both nanobodies could efficiently neutralize diverse viruses of SARS-CoV-2. The neutralizing mechanisms for the two nanobodies are further delineated by high-resolution nanobody/S-RBD complex structures. In addition, an Fc-based tetravalent nanobody format is constructed by combining Nb-015 and Nb-021. The resultant nanobody conjugate, designated as Nb-X2-Fc, exhibits significantly enhanced breadth and potency against all-tested SARS-CoV-2 variants, including Omicron sub-lineages. These data demonstrate that Nb-X2-Fc could serve as an effective drug candidate for the treatment of SARS-CoV-2 infection, deserving further in-vivo evaluations in the future.

Structural and functional basis of low-affinity SAM/SAH-binding in the conserved MTase of the multi-segmented Alongshan virus distantly related to canonical unsegmented flaviviruses.

Alongshan virus (ALSV), a newly discovered member of unclassified Flaviviridae family, is able to infect humans. ALSV has a multi-segmented genome organization and is evolutionarily distant from canonical mono-segmented flaviviruses. The virus-encoded methyltransferase (MTase) plays an important role in viral replication. Here we show that ALSV MTase readily binds S-adenosyl-L-methionine (SAM) and S-adenosyl-L-homocysteine (SAH) but exhibits significantly lower affinities than canonical flaviviral MTases. Structures of ALSV MTase in the free and SAM/SAH-bound forms reveal that the viral enzyme possesses a unique loop-element lining side-wall of the SAM/SAH-binding pocket. While the equivalent loop in flaviviral MTases half-covers SAM/SAH, contributing multiple hydrogen-bond interactions; the pocket-lining loop of ALSV MTase is of short-length and high-flexibility, devoid of any physical contacts with SAM/SAH. Subsequent mutagenesis data further corroborate such structural difference affecting SAM/SAH-binding. Finally, we also report the structure of ALSV MTase bound with sinefungin, an SAM-analogue MTase inhibitor. These data have delineated the basis for the low-affinity interaction between ALSV MTase and SAM/SAH and should inform on antiviral drug design.

Perinatal risk factors for neonatal early-onset sepsis: a meta-analysis of observational studies.

OBJECTIVE: Early-onset neonatal sepsis (EONS) remains an important cause of neonatal mortality and has many risk factors, therefore, this study aimed to investigate the perinatal risk factors for EONS. METHODS: We searched CNKI, Wan Fang, VIP, CBM, PubMed, Embase, and Web of Science to compile studies regarding the incidence of neonatal early-onset sepsis, published up to 1 May 2022. To evaluate the quality of the included studies, we used the Newcastle-Ottawa Scale, and the RevMan5.3 software was used for meta-analysis. RESULTS: A total of 17 studies were included, with 1987 cases in the case group and 4814 cases in the control group. Meta-analysis showed that perinatal asphyxia or intrauterine distress (OR = 3.00, 95% CI: 2.18-4.13), amniotic fluid meconium contamination (OR = 4.51, 95% CI: 2.31-8.81), group B streptococcal (GBS) colonization in pregnant women (OR = 2.13, 95% CI: 1.48-3.05), chorioamnionitis (OR = 4.58, 95% CI: 2.61-8.05), premature rupture of membranes (OR = 2.63, 95% CI: 2.09-3.30), lower gestational age (OR = 1.31, 95% CI: 1.18-1.44), maternal urinary or reproductive tract infection (OR = 3.61, 95% CI: 2.14-6.11), perinatal fever (OR = 3.59, 95% CI: 2.25-5.71), very low birth weight (OR = 3.79, 95% CI: 2.14-6.73), and vaginal examination ≥3 times (OR = 7.95, 95% CI: 4.04-15.64) were the perinatal risk factors for EONS. CONCLUSION: Perinatal asphyxia or intrauterine distress, meconium contamination in amniotic fluid, GBS colonization in pregnant women, chorioamnionitis, premature rupture of membranes, lower gestational age, maternal urinary tract or reproductive tract infection, perinatal fever, very low birth weight, and vaginal examinations ≥3 times may increase the risk of EONS.

Low transplacental transfer of PFASs in the small-for-gestational-age (SGA) new-borns: Evidence from a Chinese birth cohort.

Early life in utero exposure to per- and polyfluoroalkyl substances (PFASs) and infiltration through the placenta into cord blood pose significant risk to fetal development. Accumulating knowledge suggests that PFASs pass through the placenta in multiple transportation ways, not limiting to passive transport but also active transport or facilitated diffusion. Therefore, we propose that the transplacental transfer efficiency (TTE) could be re-evaluated as traditional cord to maternal ratio-based method might overlook certain biological or health information from the mother and fetus. In this study, we investigated 30 PFAS chemicals in paired maternal and cord serum from 195 births classified as small-for-gestational-age (SGA) and matched appropriate-for-gestational-age (AGA). PFASs were ubiquitously detected in the maternal and serum samples, with PFOA, PFOS, 6:2 Cl-PFESA and other dominant compounds. We adopted a modified TTE estimation method (TTEm), taking into consideration of the total burden mass of PFASs in the blood from mother to fetus. Using the modified TTEm, a significant (p < 0.05) decrease was observed in the PFAS transplacental transfer potential in SGA (1.6%-11.3%) compared to AGA (2.3%-21.1%), suggesting a reverse association between TTE and SGA birth risk. This is the first study attempted to re-evaluate the TTE of PFAS and indicates that TTEm might be more advantageous to reflect the transplacental transfer potency of chemicals particularly when transportation mechanisms are multi-faceted.

Dual Antiplatelet Therapy vs Alteplase for Patients With Minor Nondisabling Acute Ischemic Stroke: The ARAMIS Randomized Clinical Trial.

Importance: Intravenous thrombolysis is increasingly used in patients with minor stroke, but its benefit in patients with minor nondisabling stroke is unknown. Objective: To investigate whether dual antiplatelet therapy (DAPT) is noninferior to intravenous thrombolysis among patients with minor nondisabling acute ischemic stroke. Design, Setting, and Participants: This multicenter, open-label, blinded end point, noninferiority randomized clinical trial included 760 patients with acute minor nondisabling stroke (National Institutes of Health Stroke Scale [NIHSS] score ≤5, with ≤1 point on the NIHSS in several key single-item scores; scale range, 0-42). The trial was conducted at 38 hospitals in China from October 2018 through April 2022. The final follow-up was on July 18, 2022. Interventions: Eligible patients were randomized within 4.5 hours of symptom onset to the DAPT group (n = 393), who received 300 mg of clopidogrel on the first day followed by 75 mg daily for 12 (±2) days, 100 mg of aspirin on the first day followed by 100 mg daily for 12 (±2) days, and guideline-based antiplatelet treatment until 90 days, or the alteplase group (n = 367), who received intravenous alteplase (0.9 mg/kg; maximum dose, 90 mg) followed by guideline-based antiplatelet treatment beginning 24 hours after receipt of alteplase. Main Outcomes and Measures: The primary end point was excellent functional outcome, defined as a modified Rankin Scale score of 0 or 1 (range, 0-6), at 90 days. The noninferiority of DAPT to alteplase was defined on the basis of a lower boundary of the 1-sided 97.5% CI of the risk difference greater than or equal to -4.5% (noninferiority margin) based on a full analysis set, which included all randomized participants with at least 1 efficacy evaluation, regardless of treatment group. The 90-day end points were assessed in a blinded manner. A safety end point was symptomatic intracerebral hemorrhage up to 90 days. Results: Among 760 eligible randomized patients (median [IQR] age, 64 [57-71] years; 223 [31.0%] women; median [IQR] NIHSS score, 2 [1-3]), 719 (94.6%) completed the trial. At 90 days, 93.8% of patients (346/369) in the DAPT group and 91.4% (320/350) in the alteplase group had an excellent functional outcome (risk difference, 2.3% [95% CI, -1.5% to 6.2%]; crude relative risk, 1.38 [95% CI, 0.81-2.32]). The unadjusted lower limit of the 1-sided 97.5% CI was -1.5%, which is larger than the -4.5% noninferiority margin (P for noninferiority <.001). Symptomatic intracerebral hemorrhage at 90 days occurred in 1 of 371 participants (0.3%) in the DAPT group and 3 of 351 (0.9%) in the alteplase group. Conclusions and Relevance: Among patients with minor nondisabling acute ischemic stroke presenting within 4.5 hours of symptom onset, DAPT was noninferior to intravenous alteplase with regard to excellent functional outcome at 90 days. Trial Registration: ClinicalTrials.gov Identifier: NCT03661411.

The accuracy of soluble urokinase-type plasminogen activator receptor for the diagnosis of neonatal sepsis: a meta-analysis.

Background: Neonatal sepsis is one of the major causes of morbidity and mortality in newborns. However, atypical clinical manifestations and symptoms make the early diagnosis of neonatal sepsis a challenge. Relatively high-serum soluble urokinase-type plasminogen activator receptor (suPAR) has been implicated as a diagnostic biomarker for adult sepsis. Therefore, the meta-analysis is intended to explore the diagnostic value of suPAR for neonatal sepsis. Methods: The PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, China Biological Medicine Disk, and Wanfang databases were retrieved from inception to 31 December 2022 to collect diagnostic accuracy studies about suPAR for neonatal sepsis. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies using the quality assessment of diagnostic accuracy studies-2 (QUADAS-2) tool. Then, a meta-analysis was performed using Stata 15.0 software. Results: A total of six articles involving eight studies were included. The results of the meta-analysis showed that the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.89 [95%CI (0.83-0.93)], 0.94 [95%CI (0.77-0.98)], 14 [95%CI (3.5-55.2)], 0.12 [95%CI (0.08-0.18)], and 117 [95%CI (24-567)], respectively. The area under the curve (AUC) of summary receiver operator characteristic (SROC) curves was 0.92 [95%CI (0.90-0.94)]. Sensitivity analysis confirmed the stability of the results, and publication bias was not observed. Fagan's nomogram results demonstrated the clinical availability of the findings. Conclusion: Current evidence suggests that suPAR has potential diagnostic value for neonatal sepsis. Owing to the limited quality of the included studies, more high-quality studies are needed to verify the above conclusion.

Targetable elements in SARS-CoV-2 S2 subunit for the design of pan-coronavirus fusion inhibitors and vaccines.

The ongoing global pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused devastating impacts on the public health and the global economy. Rapid viral antigenic evolution has led to the continual generation of new variants. Of special note is the recently expanding Omicron subvariants that are capable of immune evasion from most of the existing neutralizing antibodies (nAbs). This has posed new challenges for the prevention and treatment of COVID-19. Therefore, exploring broad-spectrum antiviral agents to combat the emerging variants is imperative. In sharp contrast to the massive accumulation of mutations within the SARS-CoV-2 receptor-binding domain (RBD), the S2 fusion subunit has remained highly conserved among variants. Hence, S2-based therapeutics may provide effective cross-protection against new SARS-CoV-2 variants. Here, we summarize the most recently developed broad-spectrum fusion inhibitors (e.g., nAbs, peptides, proteins, and small-molecule compounds) and candidate vaccines targeting the conserved elements in SARS-CoV-2 S2 subunit. The main focus includes all the targetable S2 elements, namely, the fusion peptide, stem helix, and heptad repeats 1 and 2 (HR1-HR2) bundle. Moreover, we provide a detailed summary of the characteristics and action-mechanisms for each class of cross-reactive fusion inhibitors, which should guide and promote future design of S2-based inhibitors and vaccines against new coronaviruses.

Late Miocene Leaves and Endocarps of Choerospondias (Anacardiaceae) from Zhejiang, Eastern China: Implications for Paleogeography and Paleoclimate.

Choerospondias (Anacardiaceae), characterized by radially arranged germination pores near the top, is a monotypic genus mainly distributed in subtropical and tropical eastern Asia, while fossil records indicate a wide distribution throughout Eurasia during the Cenozoic. In this study, we reported three-dimensionally preserved Choerospondias endocarps, and the associated compressed leaves from the late Miocene Shengxian Formation in Tiantai, Zhejiang, eastern China. The plant remains were assigned to two new fossil species. The endocarps were identified as Choerospondiastiantaiensis sp. nov., and the leaves were identified as Choerospondias mioaxillaris sp. nov. Based on fossil records and climate fluctuation during the Cenozoic, we conclude that Choerospondias may have originated from Europe in the early Eocene and then spread to Asia along the coast and island chains of the Tethys and Paratethys oceans. The distribution position of the current fossils was adjacent to the northern boundary of the modern distribution of Choerospondias in East Asia, indicating that the distribution pattern of Choerospondias in East Asia likely formed no later than the late Miocene. We reconstructed the late Miocene paleoclimate of eastern Zhejiang by using the method of climate analysis of endemic species (CAES), and then compared it to the data reconstructed in previous studies. The results indicate that the late Miocene climate in eastern Zhejiang was similar to or warmer and more humid than the modern climate in this region.

A New Species of Comptonia (Myricaceae) from the Early Miocene of Central Inner Mongolia, China, and Phytogeographic History of Sweet-Fern.

Comptonia (Myricaceae) is well known as a monotypic genus living only in eastern North America; however, fossils show that the genus occurred extensively in the Northern Hemisphere during the Cenozoic. We observed dozens of Comptonia leaf fossils from the early Miocene in Zhuozi, China. The leaf architecture characteristics and epidermal features of the fossil specimens are described in detail here for the first time, and they were assigned to a new species: Comptonia hirsuta. The fruit fossils collected simultaneously from the same layer were assigned to Comptonia tymensis. The global fossil records indicate that the spatial distribution range of Comptonia reached its peak in both the Eocene and Miocene as two warm periods and then gradually decreased in the Oligocene, as well as after the late Miocene, because of the cooling global climate. Furthermore, the Comptonia taxon in East Asia may have migrated from North America via the Bering route in the late Paleocene or Eocene. Plant exchange between western Europe and eastern North America possibly occurred during the Eocene via the Thulean route. Phytogeographic variation in the Comptonia fossils from China also indicates that the reason for the disappearance of Comptonia from China may not only be due to the prolonged cooling and drying after the late Miocene, but also due to its progenitive pattern.

Effect of Remote Ischemic Conditioning vs Usual Care on Neurologic Function in Patients With Acute Moderate Ischemic Stroke: The RICAMIS Randomized Clinical Trial.

Importance: Preclinical and clinical studies have suggested a neuroprotective effect of remote ischemic conditioning (RIC), which involves repeated occlusion/release cycles on bilateral upper limb arteries; however, robust evidence in patients with ischemic stroke is lacking. Objective: To assess the efficacy of RIC for acute moderate ischemic stroke. Design, Setting, and Participants: This multicenter, open-label, blinded-end point, randomized clinical trial including 1893 patients with acute moderate ischemic stroke was conducted at 55 hospitals in China from December 26, 2018, through January 19, 2021, and the date of final follow-up was April 19, 2021. Interventions: Eligible patients were randomly assigned within 48 hours after symptom onset to receive treatment with RIC (using a pneumatic electronic device and consisting of 5 cycles of cuff inflation for 5 minutes and deflation for 5 minutes to the bilateral upper limbs to 200 mm Hg) for 10 to 14 days as an adjunct to guideline-based treatment (n = 922) or guideline-based treatment alone (n = 971). Main Outcomes and Measures: The primary end point was excellent functional outcome at 90 days, defined as a modified Rankin Scale score of 0 to 1. All end points had blinded assessment and were analyzed on a full analysis set. Results: Among 1893 eligible patients with acute moderate ischemic stroke who were randomized (mean [SD] age, 65 [10.3] years; 606 women [34.1%]), 1776 (93.8%) completed the trial. The number with excellent functional outcome at 90 days was 582 (67.4%) in the RIC group and 566 (62.0%) in the control group (risk difference, 5.4% [95% CI, 1.0%-9.9%]; odds ratio, 1.27 [95% CI, 1.05-1.54]; P = .02). The proportion of patients with any adverse events was 6.8% (59/863) in the RIC group and 5.6% (51/913) in the control group. Conclusions and Relevance: Among adults with acute moderate ischemic stroke, treatment with remote ischemic conditioning compared with usual care significantly increased the likelihood of excellent neurologic function at 90 days. However, these findings require replication in another trial before concluding efficacy for this intervention. Trial Registration: ClinicalTrials.gov Identifier: NCT03740971.

Mesenchymal stem cell-derived extracellular vesicles for immunomodulation and regeneration: a next generation therapeutic tool?

Mesenchymal stem cells (MSCs) can be widely isolated from various tissues including bone marrow, umbilical cord, and adipose tissue, with the potential for self-renewal and multipotent differentiation. There is compelling evidence that the therapeutic effect of MSCs mainly depends on their paracrine action. Extracellular vesicles (EVs) are fundamental paracrine effectors of MSCs and play a crucial role in intercellular communication, existing in various body fluids and cell supernatants. Since MSC-derived EVs retain the function of protocells and have lower immunogenicity, they have a wide range of prospective therapeutic applications with advantages over cell therapy. We describe some characteristics of MSC-EVs, and discuss their role in immune regulation and regeneration, with emphasis on the molecular mechanism and application of MSC-EVs in the treatment of fibrosis and support tissue repair. We also highlight current challenges in the clinical application of MSC-EVs and potential ways to overcome the problem of quality heterogeneity.

A Potent Neutralizing Nanobody Targeting the Spike Receptor-Binding Domain of SARS-CoV-2 and the Structural Basis of Its Intimate Binding.

The continuous spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) around the world has raised unprecedented challenges to the human society. Antibodies and nanobodies possessing neutralization activity represent promising drug candidates. In this study, we report the identification and characterization of a potent SARS-CoV-2 neutralizing nanobody that targets the viral spike receptor-binding domain (S-RBD). The nanobody, termed as Nb-007, engages SARS-CoV-2 S-RBD with the two-digit picomolar binding affinity and shows outstanding virus entry-inhibition activity. The complex structure of Nb-007 bound to SARS-CoV-2 S-RBD reveals an epitope that is partially overlapping with the binding site for the human receptor of angiotensin-converting enzyme 2 (ACE2). The nanobody therefore exerts neutralization by competing with ACE2 for S-RBD binding, which is further ascertained by our in-vitro biochemical analyses. Finally, we also show that Nb-007 reserves promising, though compromised, neutralization activity against the currently-circulating Delta variant and that fusion of the nanobody with Fc dramatically increases its entry-inhibition capacity. Taken together, these data have paved the way of developing Nb-007 as a drug-reserve for potential treatment of SARS-CoV-2 related diseases.

An engineered 5-helix bundle derived from SARS-CoV-2 S2 pre-binds sarbecoviral spike at both serological- and endosomal-pH to inhibit virus entry.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related sarbecoviruses enter host cells by receptor-recognition and membrane-fusion. An indispensable step in fusion is the formation of 6-helix bundle by viral spike heptad repeats 1 and 2 (HR1 and HR2). Here, we report the construction of 5-helix bundle (5HB) proteins for virus infection inhibition. The optimal construct inhibits SARS-CoV-2 pseudovirus entry with sub-micromolar IC50. Unlike HR2-based peptides that cannot bind spike in the pre-fusion conformation, 5HB features with the capability of binding to pre-fusion spike. Furthermore, 5HB binds viral HR2 at both serological- and endosomal-pH, highlighting its entry-inhibition capacity when SARS-CoV-2 enters via either cell membrane fusion or endosomal route. Finally, we show that 5HB could neutralize S-mediated entry of the predominant SARS-CoV-2 variants and a wide spectrum of sarbecoviruses. These data provide proof-of-concept evidence that 5HB might be developed for the prevention and treatment of SARS-CoV-2 and other emerging sarbecovirus infections.

Differential effects of macrophage subtypes on SARS-CoV-2 infection in a human pluripotent stem cell-derived model.

Dysfunctional immune responses contribute critically to the progression of Coronavirus Disease-2019 (COVID-19), with macrophages as one of the main cell types involved. It is urgent to understand the interactions among permissive cells, macrophages, and the SARS-CoV-2 virus, thereby offering important insights into effective therapeutic strategies. Here, we establish a lung and macrophage co-culture system derived from human pluripotent stem cells (hPSCs), modeling the host-pathogen interaction in SARS-CoV-2 infection. We find that both classically polarized macrophages (M1) and alternatively polarized macrophages (M2) have inhibitory effects on SARS-CoV-2 infection. However, M1 and non-activated (M0) macrophages, but not M2 macrophages, significantly up-regulate inflammatory factors upon viral infection. Moreover, M1 macrophages suppress the growth and enhance apoptosis of lung cells. Inhibition of viral entry using an ACE2 blocking antibody substantially enhances the activity of M2 macrophages. Our studies indicate differential immune response patterns in distinct macrophage phenotypes, which could lead to a range of COVID-19 disease severity.

Risk factors for necrotizing enterocolitis in neonates: A meta-analysis.

Objective: The objective is to identify the risk factors for necrotizing enterocolitis (NEC) in neonates by a meta-analysis, and to provide a reference for the prevention of NEC. Methods: The databases, including Chinese Biomedical Literature Datebase, China National Knowledge Infrastructure, Wanfang database, and Weipu Periodical database, PubMed, Web of Science, Embase, Cochrane Library, were searched for studies on the risk factors for NEC in neonates. The meta-analysis was carried out with the aid of Stata software. Results: A total of 52 studies were included, with 48 case-control studies and 4 cohort studies. There were 166,580 neonates in total, with 33,522 neonates in the case group and 133,058 neonates in the control group. The meta-analysis showed that gestational diabetes (OR = 3.62, 95% CI:1.77-7.41), premature rupture of membranes (OR = 3.81, 95% CI:1.16-12.52), low birth weight (OR = 3.00, 95% CI:2.26-3.97), small for gestational age (OR = 1.85, 95% CI:1.15-2.97), septicemia (OR = 4.34, 95% CI:3.06-6.15), blood transfusion (OR = 3.08, 95% CI:2.16-4.38), congenital heart disease (OR = 2.73, 95% CI:1.10-6.78), respiratory distress syndrome (OR = 2.12, 95% CI:1.24-3.63), premature birth (OR = 5.63, 95% CI:2.91-10.92), pneumonia (OR = 4.07, 95% CI:2.84-5.82) were risk factors for NEC in neonates. Breastfeeding (OR = 0.37, 95% CI:0.23-0.59), take probiotics (OR = 0.30, 95% CI:0.22-0.40), prenatal use of glucocorticoids (OR = 0.39, 95% CI:0.30-0.50), Hyperbilirubinemia (OR = 0.28, 95% CI:0.09-0.86) were protective factors for NEC in neonates. Conclusions: Gestational diabetes, premature rupture of membranes, low birth weight, small for gestational age, septicemia, blood transfusion, congenital heart disease, respiratory distress syndrome, premature birth, and pneumonia may increase the risk of NEC in neonates. Breastfeeding, taking probiotics, prenatal use of glucocorticoids, and Hyperbilirubinemia may reduce the risk of NEC in neonates.

Downregulation of microRNA-185 expression in diabetic patients increases the expression of NOS2 and results in vascular injury.

The aim of the present study was to investigate the regulatory effect and mechanism of microRNA (miR)-185 in diabetic angiopathy. The expression of miR-185 and nitric oxide synthase 2 (NOS2) in the blood from diabetic patients was examined by reverse transcription-quantitative PCR and enzyme-linked immunosorbent assay. After establishment of diabetic rats, the expression of miR-185 and NOS2 in vascular tissues and blood was also measured. Then, miR-185 was overexpressed in HMEC-1 cells and the expression of NOS2 was determined. Dual-luciferase reporter assay was used to identify the direct interaction between miR-185 and NOS2 mRNA. The expression of NOS2 was upregulated and the expression of miR-185 was downregulated in the blood from patients with diabetes. Vascular tissues and blood of diabetic rats showed similar trends compared with that of human. HMEC-1 cells with overexpression of miR-185 had decreased expression of NOS2. Dual-luciferase reporter assay demonstrated the direct binding between miR-185 and NOS2. The present study demonstrates that upregulation of NOS2 in diabetic patients is associated with the downregulation of miR-185, which participates in the progression of diabetes possibly through regulating NOS2 expression.