Dual-Ligand Europium-Organic Gels as a Highly Efficient Anodic Annihilation Electrochemiluminescence Emitter for Ultrasensitive Detection of MicroRNA.

In this study, a novel europium dual-ligand metal-organic gel (Eu-D-MOGs) with high-efficient anodic annihilation electrochemiluminescence (ECL) was synthesized as an ECL emitter to construct a biosensor for ultrasensitive detection of microRNA-221 (miR-221). Impressively, compared to the ECL signal of europium single-ligand metal-organic gels (Eu-S-MOGs), the ECL signal of Eu-D-MOGs was significantly improved since the two organic ligands could jointly replace the H2O and coordinate with Eu3+, which could remarkably reduce the nonradiative vibrational energy transfer caused by the coordination between H2O and Eu3+ with a high coordination demand. In addition, Eu-D-MOGs could be electrochemically oxidized to Eu-D-MOGs•+ at 1.45 V and reduced to Eu-D-MOGs•- at 0.65 V to achieve effective annihilation of ECL, which overcame the side reaction brought by the remaining emitters at negative potential. This benefited from the annihilation ECL performance of the central ion Eu3+ caused by its redox in the electrochemical process. Furthermore, the annihilation ECL signal of Eu3+ could be improved by sensitizing Eu3+ via the antenna effect. In addition, combined with the improved rolling circle amplification-assisted strand displacement amplification strategy (RCA-SDA), a sensitive biosensor was constructed for the sensitive detection of miR-221 with a low detection limit of 5.12 aM and could be successfully applied for the detection of miR-221 in the lysate of cancer cells. This strategy offered a unique approach to synthesizing metal-organic gels as ECL emitters without a coreactant for the construction of ECL biosensing platforms in biomarker detection and disease diagnosis.

Characterizing fitness and immune escape of SARS-CoV-2 EG.5 sublineage using elderly serum and nasal organoid.

SARS-CoV-2 Omicron variant has evolved into sublineages. Here, we compared the neutralization susceptibility and viral fitness of EG.5.1 and XBB.1.9.1. Serum neutralization antibody titer against EG.5.1 was 1.71-fold lower than that for XBB.1.9.1. However, there was no significant difference in virus replication between EG.5.1 and XBB.1.9.1 in human nasal organoids and TMPRSS2/ACE2 over-expressing A549 cells. No significant difference was observed in competitive fitness and cytokine/chemokine response between EG.5.1 and XBB.1.9.1. Both EG.5.1 and XBB.1.9.1 replicated more robustly in the nasal organoid from a younger adult than that from an older adult. Our findings suggest that enhanced immune escape contributes to the dominance of EG.5.1 over earlier sublineages. The combination of population serum susceptibility testing and viral fitness evaluation with nasal organoids may hold promise in risk assessment of upcoming variants. Utilization of serum specimens and nasal organoid derived from older adults provides a targeted risk assessment for this vulnerable population.

Modeling an evaluation of the efficacy of the novel neuroanalgesic drug mirogabalin for diabetic peripheral neuropathic pain and postherpetic neuralgia therapy.

Diabetic peripheral neuropathic pain (DPNP) and postherpetic neuralgia (PHN) are challenging and often intractable complex medical conditions, with a substantial impact on the quality of life. Mirogabalin, a novel voltage-gated Ca2+ channel α2δ ligand, was approved for the indication of DPNP and PHN. However, the time course of effects has not yet been clarified.We aimed to establish pharmacodynamic and placebo effect models of mirogabalin and pregabalin in DPNP and PHN, and to quantitatively compare the efficacy characteristics (maximum efficacy, onset time, and other pharmacodynamic parameters) and safety of mirogabalin and pregabalin. Public databases were comprehensively searched for randomized placebo-controlled clinical trials. A model-based meta-analysis (MBMA) was developed to describe the time course of drug efficacy and placebo effects. Adverse events were compared using a fixed-effects meta-analysis. Sixteen studies including 5,147 participants were eligible for this study. The placebo effect was relatively high and gradually increased with time, and it required at least eight weeks to reach a plateau. The pharmacodynamic model revealed that the maximum pure efficacy for mirogabalin and pregabalin was approximately -7.85 % and -8.86 %, respectively; the efficacy of mirogabalin to relieve DPNP and PHN was not superior to that of pregabalin, and both drugs had similar safety. While the rate constant of the onset rate of pregabalin was approximately thrice as high as that of mirogabalin. In addition, the baseline level of pain was an important factor affecting pregabalin efficacy. These findings are helpful in evaluating the clinical extension value of mirogabalin. They suggest that the high placebo effect and the baseline level of pain should be considered when grouping patients in future research and development of voltage-gated Ca2+ channel neuroanalgesic.

TET3 gene rs828867 G>A polymorphism reduces neuroblastoma risk in Chinese children.

Objective: Neuroblastoma (NB) is a prevalent pediatric tumor originating from primordial neural crest cells. As one of the latest epigenetics investigations focuses, RNA 5-methylcytosine (m5C) is closely related to cancer risk. TET methylcytosine dioxygenase 3 (TET3) is a demethylase for m5C modification. Whether there is an association between TET3 gene polymorphisms and neuroblastoma risk remains unclear. Methods: We conducted an epidemiological study in 402 patients and 473 controls to evaluate the relationship between TET3 gene SNPs (rs7560668 T > C, rs828867 G > A, and rs6546891 A > G) and NB susceptibility. Results: Our results showed that rs828867 G > A significantly reduced NB risk in Chinese children [GA vs. GG, adjusted odds ratio (OR) = 0.72, 95% confidence interval (CI) = 0.52-0.98, P=0.040; GA/AA vs. GG, adjusted OR = 0.74, 95% CI = 0.55-0.998, P=0.048]. Individuals with 2-3 risk genotypes had a significantly higher NB risk than those with 0-1 risk genotypes (adjusted OR = 1.40, 95% CI = 1.04-1.88, P=0.027). The stratified analysis showed that the rs828867 G > A associated with decreased NB risk is remarkable among children aged >18 months (adjusted OR = 0.67, 95% CI = 0.46-0.96, P=0.029) and patients at clinical III + IV stages (adjusted OR = 0.67, 95% CI = 0.45-0.98, P=0.040). Compared with the 0-1 risk genotype, the concurrence of 2-3 risk genotypes significantly increased NB risk in the following subgroups: children aged >18 months and patients at clinical III + IV stages. GTEx analysis suggested that rs828867 G > A was significantly associated with RP11-287D1.4 and POLE4 mRNA expression. Conclusions: Overall, our results revealed that rs828867 G > A in the TET3 gene is significantly associated with predisposition to NB.

Distinct interactions of ericoid mycorrhizae and plant growth-promoting bacteria: impacts on blueberry growth and heat resilience.

Blueberries confront substantial challenges from climate change, such as rising temperatures and extreme heat, necessitating urgent solutions to ensure productivity. We hypothesized that ericoid mycorrhizal fungi (ErM) and plant growth-promoting bacteria (PGPB) would establish symbiotic relationships and increase heat stress tolerance in blueberries. A growth chamber study was designed with low (25/20°C) and high temperature (35/30°C) conditions with micropropagated blueberry plantlets inoculated with ErM, PGPB, and both. Gas exchange and chlorophyll fluorescence properties of the leaves were monitored throughout the growth. At harvest, biochemical assays and biomass analysis were performed to evaluate potential oxidative stress induced by elevated temperatures. ErM application boosted root biomass under 25/20°C conditions but did not impact photosynthetic efficiency. In contrast, PGPB demonstrated a dual role: enhancing photosynthetic capacity and reducing stomatal conductance notably under 35/30°C conditions. Moreover, PGPB showcased conflicting effects, reducing oxidative damage under 25/20°C conditions while intensifying it during 47°C heat shock. A significant highlight lies in the opposing effects of ErM and PGPB on root growth and stomatal conductance, signifying their reciprocal influence on blueberry plant behavior, which may lead to increased water uptake or reduced water use. Understanding these complex interactions holds promise for refining sustainable strategies to overcome climate challenges.

Educating families of brain injury patients during acute rehabilitation: a quality improvement project.

ABSTRACT: Lack of information is cited as a source of distress for caregivers of patients with brain injury during the recovery process. This is a quality improvement project with the purpose of educating family members of brain injury patients about acute inpatient rehabilitation and providing a reliable source of information through the Model Systems Knowledge Translation Center (MSKTC) Traumatic Brain Injury Model Systems (TBIMS) Factsheets. The study was conducted in the brain injury unit of an acute inpatient rehabilitation facility and a total of n = 32 family members participated in the study. Educational sessions were provided verbally by phone based on the MSKTC-TBIMS "Traumatic Brain Injury and Acute Inpatient Rehabilitation" Factsheet. Surveys with five confidence statements and Likert scale graded responses were verbally administered by phone immediately before and after each educational session to evaluate for understanding. There was a statistically significant increase in confidence for all five confidence statements when comparing pre-and post-education responses (p < 0.05, Wilcoxon signed-rank test). This quality improvement project thereby presents an effective and feasible framework for teaching, improving communication, and providing valuable information to families early in the brain injury rehabilitation course.

Trends in Health Service Use for Dry Eye Disease From 2017 to 2021: A Real-World Analysis of 369,755 Outpatient Visits.

Purpose: We aimed to analyze the trends and patterns in outpatient health service treatment of dry eye disease (DED) using real-world data from Yinzhou District in China. Methods: The Yinzhou Health Information System is a comprehensive database including electronic medical records from 277 medical institutions representing over 1.64 million residents. We extracted outpatient records from January 1, 2017, to December 31, 2021, that included the first diagnosis of DED according to the International Classification of Diseases, 10th Revision (H04.101, H04.103, H11.104, H16.202, or H18.803). We analyzed the trends and patterns of DED outpatient visits using the Mann-Kendall trend test and Cochran-Armitage trend test. Results: We identified a total of 369,755 outpatient visits from 145,712 patients with DED of all ages (60.37% female; 54.10% 50 years or older). Primary medical institutions had the largest number of DED outpatient visits (42%), followed by tertiary medical institutions (35%). Over the 5-year period, the number of DED outpatient visits increased from 59,260 to 90,807 (53.23%). We observed significant consecutive annual proportion increases in females (from 61.09% to 62.01%; P = 0.001), patients 50 years or older (from 55.10% to 60.08%; P < 0.001), and outpatient visits in primary medical institutions (from 33.19% to 48.75%; P < 0.001). Conclusions: Our study found an increase in outpatient health service use for DED in Yinzhou from 2017 to 2021, with higher proportions and increases among females, patients 50 years or older, and primary medical institutions. Translational Relevance: The rapid growth in the prevalence of DED indicates high eye healthcare needs in patients.

Fe single atoms encapsulated in N, P-codoped carbon nanosheets with enhanced peroxidase-like activity for colorimetric detection of methimazole.

Excessive use of antithyroid drug methimazole (MMI) in pharmaceutical samples can cause hypothyroidism and symptoms of metabolic decline. Hence, it is urgent to develop rapid, low cost and accurate colorimetric method with peroxidase-like nanozymes for determination of MMI in medical, nutrition and pharmaceutical studies. Herein, Fe single atoms were facilely encapsulated into N, P-codoped carbon nanosheets (Fe SAs/NP-CSs) by a simple pyrolysis strategy, as certified by a series of characterizations. UV-vis absorption spectroscopy was employed to illustrate the high peroxidase-mimicking activity of the resultant Fe SAs/NP-CSs nanozyme through the typical catalysis of 3,3',5,5'-tetramethylbenzidine (TMB) oxidation. The catalytic mechanism was scrutionously investigated by the fluorescence spectroscopy and electron paramagnetic resonance (EPR) tests. Additionally, the introduced MMI had the ability to reduce the oxidation of TMB (termed oxTMB) as a peroxidase inhibitor, coupled by fading the blue color. By virtue of the above findings, a visual colorimetric sensor was established for dual detection of methimazole (MMI) with a linear scope of 5-50 mM and a LOD of 1.57 mM, coupled by assay of H2O2 at a linear range of 3-50 mM. According to the irreversible oxidation of the drug, its screening with acceptable results was achieved on the sensing platform even in commercial tablets The Fe SAs/NP-CSs nanozyme holds great potential for clinical diagnosis and drug analysis.

Verteporfin regulates corneal neovascularization through inhibition of YAP protein activation.

Corneal neovascularization (CNV) is a vision-threatening disease that is becoming a growing public health concern. While Yes-associated protein (YAP) plays a critical role in neovascular disease and allow for the sprouting angiogenesis. Verteporfin (VP) is a classical inhibitor of the YAP-TEAD complex, which is used for clinical treatment of neovascular macular degeneration through photodynamic therapy. The purpose of this study is to explore the effect of verteporfin (VP) on the inhibition of CNV and its potential mechanism. Rat CNV model were established by suturing in the central cornea and randomly divided into three groups (control, CNV and VP group). Neovascularization was observed by slit lamp to extend along the corneal limbus to the suture line. RNA-sequencing was used to reveal the related pathways on the CNV and the results revealed the vasculature development process and genes related with angiogenesis in CNV. In CNV group, we detected the nuclear translocation of YAP and the expression of CD31 in corneal neovascular endothelial cells through immunofluorescence. After the application of VP, the proliferation, migration and the tube formation of HUVECs were significantly inhibited. Furthermore, VP showed the CNV inhibition by tail vein injection without photoactivation. Then we found that the expression of phosphorylated YAP significantly decreased, and its downstream target protein connective tissue growth factor (CTGF) increased in the CNV group, while the expression was just opposite in other groups. Besides, both the expression of vascular endothelial growth factor receptor 2 (VEGFR2) and cofilin significantly increased in CNV group, and decreased after VP treatment. Therefore, we conclude that Verteporfin could significantly inhibited the CNV without photoactivation by regulating the activation of YAP.

Functional TET2 gene polymorphisms increase the risk of neuroblastoma in Chinese children.

The 5-methylcytosine (m5C) is the key chemical modification in RNAs. As one of the demethylases in m5C, TET2 has been shown as a tumor suppressor. However, the impact of TET2 gene polymorphisms on neuroblastoma has not been elucidated. 402 neuroblastoma patients and 473 controls were genotyped for TET2 gene polymorphisms using the TaqMan method. The impact of TET2 gene polymorphisms on neuroblastoma susceptibility was determined using multivariate logistic regression analysis. We also adopted genotype-tissue expression database to explore the impact of TET2 gene polymorphisms on the expression of host and nearby genes. We used the R2 platform and Sangerbox tool to analyze the relationship between gene expression and neuroblastoma risk and prognosis through non-parametric testing and Kaplan-Meier analysis, respectively. We found the TET2 gene polymorphisms (rs10007915 G > C and rs7670522 A > C) and the combined 2-5 risk genotypes can significantly increase neuroblastoma risk. Stratification analysis showed that these significant associations were more prominent in certain subgroups. TET2 rs10007915 G > C and rs7670522 A > C are significantly associated with reduced expression of TET2 mRNA. Moreover, lower expression of TET2 gene is associated with high risk, MYCN amplification, and poor prognosis of neuroblastoma. The rs10007915 G > C and rs7670522 A > C are significantly related to the increased expression of inorganic pyrophosphatase 2 mRNA, and higher expression of PPA2 gene is associated with high risk, MYCN amplification, and poor prognosis of neuroblastomas. In summary, TET2 rs10007915 G > C and rs7670522 A > C significantly confer neuroblastoma susceptibility, and further research is needed to investigate the underlying mechanisms.

Factors associated with progressive anisometropia after bilateral intraocular lens implantation in patients with pediatric cataract.

OBJECTIVES: To identify factors associated with progressive anisometropia after bilateral intraocular lens (IOL) implantation in patients with pediatric cataract. METHODS: Clinical and standardized questionnaire data were collected for Sixty-eight patients with pediatric cataract (136 eyes) who underwent bilateral IOL implantation and at least 1 year of follow-up. Univariate and multivariate linear regression models were used to identify factors associated with postoperative anisometropia. RESULTS: The median age at IOL implantation was 3.2 years (range: 1-12.4 years), and median follow-up time was 5.7 years (range: 1.1-14 years). At 1 month postoperatively and at the last follow-up, there were 19 (27%) and 31 (46%) cases of anisometropia ≥1 D, 9 (13%) and 15 (22%) cases of anisometropia ≥2 D, and 2 (3%) and 9 (13%) cases of anisometropia ≥3 D, respectively. Compared with 1 month postoperatively, the amount of anisometropia increased in 45 (67%) patients. Greater anisometropia one year or more after bilateral IOL implantation was associated with larger intereye difference in IOL power (P = 0.032, 95%CI 0.013 to 0.285), intereye difference in preoperative axial length (P = 0.018, 95%CI -1.247 to -0.123), presence of strabismus (P = 0.017, 95%CI 0.063-0.601), anisometropia at 1 month postoperatively (P = 0.001, 95%CI 0.126-0.478), and intereye difference in axial length at the last follow-up (P = 0.047, 95%CI 0.005-0.627). CONCLUSION: Anisometropia might progress after bilateral IOL implantation in patients with pediatric cataract. Greater intereye difference in IOL power, presence of strabismus might increase the potential of progressive anisometropia.

Autoantibodies against angiotensin-converting enzyme 2 (ACE2) after COVID-19 infection or vaccination.

Autoantibodies against angiotensin-converting enzyme 2 (ACE2) are frequently reported in patients during coronavirus disease 2019 (COVID-19) with evidence for a pathogenic role in severe infection. However, little is known of the prevalence or clinical significance of ACE2 autoantibodies in late convalescence or following COVID-19 vaccination. In this study, we measured ACE2 autoantibodies in a cohort of 182 COVID-19 convalescent patients, 186 COVID-19 vaccine recipients, and 43 adolescents with post-mRNA vaccine myopericarditis using two ACE2 enzymatic immunoassays (EIAs). ACE2 IgM autoantibody EIA median optical densities (ODs) were lower in convalescent patients than pre-COVID-19 control samples with only 2/182 (1.1%) convalescents testing positive. Similarly, only 3/182 (1.6%) convalescent patients tested positive for ACE2 IgG, but patients with history of moderate-severe COVID-19 tended to have significantly higher median ODs than controls and mild COVID-19 patients. In contrast, ACE2 IgG antibodies were detected in 10/186 (5.4%) COVID-19 vaccine recipients after two doses of vaccination. Median ACE2 IgG EIA ODs of vaccine recipients were higher than controls irrespective of the vaccine platform used (inactivated or mRNA). ACE2 IgG ODs were not correlated with surrogate neutralizing antibody levels in vaccine recipients. ACE2 IgG levels peaked at day 56 post-first dose and declined within 12 months to baseline levels in vaccine recipients. Presence of ACE2 antibodies was not associated with adverse events following immunization including myopericarditis. One convalescent patient with ACE2 IgG developed Guillain-Barre syndrome, but causality was not established. ACE2 autoantibodies are observed in COVID-19 vaccine recipients and convalescent patients, but are likely innocuous.

Humoral and cellular immunity against different SARS-CoV-2 variants in patients with chronic kidney disease.

Chronic kidney disease (CKD) patients are at higher risk of severe COVID-19. Humoral and cellular immunity from prior infection or vaccination are important for protection, but the neutralizing antibody (nAb) response against SARS-CoV-2 variants is impaired. We investigated the variant-specific nAb and T cell immunity among CKD patients. Adult CKD patients were recruited between August and October 2022. nAb against the SARS-CoV-2 (ancestral strains and four Omicron sublineages) and T cell response were measured using the live virus neutralization assay and interferon-gamma release assay (IGRA). The correlation between nAb/T-cell response and subsequent infection after recruitment were also determined. Among the 88 recruited patients, 95.5% had prior infection or had completed the primary vaccine series. However, only 77.3% had detectable nAb against at least one SARS-CoV-2 strains, 59.1% tested positive in IGRA, and 52.3% had detectable nAb and tested positive in the IGRA. The nAb geometic mean titers (GMTs) against XBB.1, BA.5 and BA.2.3.20 were significantly lower than those against BA.2 and ancestral strain. Prior SARS-CoV-2 infection was associated with elevated nAb and T cell response. More kidney transplant recipients (KTRs) showed absent nAb and T cell response (36.8% vs. 10.1%), despite a higher prevalence of vaccine booster in this population (94.7% vs. 50.7%). Lower levels of nAb titer and T cell response were significantly associated with subsequent infection. A considerable proportion of CKD patients, especially KTRs, showed absence of humoral and cellular protective immunity against SARS-CoV-2. Strategies to improve immunogenicity in this population are urgently needed.

Determination of seroprevalence and kinetics of humoral response using mpox virus A29 protein.

BACKGROUND: Mpox virus (MPXV), previously known as monkeypox virus, has spread globally in 2022. An accurate and convenient antibody test is essential for the determination of seroprevalence and for studying immune response after natural infection or vaccination. Most seroprevalence or vaccine studies used either live MPXV (or vaccinia virus [VACV]) or inactivated MPXV (or VACV) culture lysate for serological assays, but MPXV culture can only be performed in biosafety level 3 (BSL-3) facilities. Here, we developed and evaluated an enzyme immunoassay (EIA) based on the MPXV A29 surface envelope protein. METHODS: We compared the specificity of the MPXV A29, VACV A27, and VACV lysate EIA using serum specimens collected prior to the global spread of MPXV. Next, we performed these EIAs for serum specimens collected from two mpox patients and an MVA-BN vaccine recipient. We also assessed the kinetics of plasmblast and MPXV A29-specific B-cell response. RESULTS: Using sera collected from different age groups in Hong Kong, we found that most individuals, including those born before 1981 who have received the smallpox vaccine, tested negative using the MPXV A29 protein. MPXV A29-specific antibody could be detected in the serum of mpox patients and an MVA-BN recipient. In a mpox patient, the frequency of plasmablast and MPXV A29-specific B cell peaked on day 8 post-symptom onset and gradually decreased. Finally, we demonstrated that antibodies against the A29 protein can be used for immunofluorescence staining of MPXV-infected cells. CONCLUSIONS: MPXV A29 protein is suitable for studying the immune response against MPXV infection.

Since early 2022, mpox (monkeypox) has been reported in many countries where the disease is not regularly found to occur. The aim of the study was to develop and evaluate the performance of laboratory assays based on the mpox virus surface protein, named A29. We found our assays could accurately distinguish naturally infected cases from smallpox vaccine recipients as well as those who were neither infected nor vaccinated. Our assays provide a useful tool for studying the host immune response to mpox virus.

Mild Photothermal Therapy Prevents Posterior Capsule Opacification through Cytoskeletal Remodeling.

Cataract is the first leading cause of blindness in the world and posterior capsule opacification (PCO) is the most common long-term complication after surgery. The primary pathogenic processes contributing to PCO are the proliferation and migration of residual lens epithelial cells (LECs). This study aimed to explore the mild photothermal effect on LECs. Interestingly, this work finds that the mild photothermal effect significantly inhibited the proliferation and migration of LECs. The live cell fluorescence imaging reveals that the remodeling of the actin cytoskeleton and cell morphology attributed to the inhibition effect. Further mechanistic studies at molecular level suggest that the mild photothermal effect can regulate the phosphorylation of ERM, YAP, and Cofilin and thereby affect the proliferation and migration of LECs. In order to explore the potential clinical application of mild photothermal therapy for PCO prevention, PDA/PVA gel rings with photothermal effect is prepared by the repeated freeze-thaw method and conducted experiments in vivo, which achieved favorable PCO prevention effect. Overall, this study shows that the mild photothermal effect can regulate the proliferation and migration of LECs through cytoskeletal remodeling and the results of experiments in vivo demonstrate that mild photothermal effect is a promising approach for PCO prevention.

Broad-spectrum humanized monoclonal neutralizing antibody against SARS-CoV-2 variants, including the Omicron variant.

Introduction: Therapeutic monoclonal antibodies (mAbs) against the SARS-CoV-2 spike protein have been shown to improve the outcome of severe COVID-19 patients in clinical trials. However, novel variants with spike protein mutations can render many currently available mAbs ineffective. Methods: We produced mAbs by using hybridoma cells that generated from mice immunized with spike protein trimer and receptor binding domain (RBD). The panel of mAbs were screened for binding and neutralizing activity against different SARS-CoV-2 variants. The in vivo effectiveness of WKS13 was evaluated in a hamster model. Results: Out of 960 clones, we identified 18 mAbs that could bind spike protein. Ten of the mAbs could attach to RBD, among which five had neutralizing activity against the ancestral strain and could block the binding between the spike protein and human ACE2. One of these mAbs, WKS13, had broad neutralizing activity against all Variants of Concern (VOCs), including the Omicron variant. Both murine or humanized versions of WKS13 could reduce the lung viral load in hamsters infected with the Delta variant. Conclusions: Our data showed that broad-spectrum high potency mAbs can be produced from immunized mice, which can be used in humans after humanization of the Fc region. Our method represents a versatile and rapid strategy for generating therapeutic mAbs for upcoming novel variants.

Rational design of a booster vaccine against COVID-19 based on antigenic distance.

Current COVID-19 vaccines are highly effective against symptomatic disease, but repeated booster doses using vaccines based on the ancestral strain offer limited additional protection against SARS-CoV-2 variants of concern (VOCs). To address this, we used antigenic distance to in silico select optimized booster vaccine seed strains effective against both current and future VOCs. Our model suggests that a SARS-CoV-1-based booster vaccine has the potential to cover a broader range of VOCs. Candidate vaccines including the spike protein from ancestral SARS-CoV-2, Delta, Omicron (BA.1), SARS-CoV-1, or MERS-CoV were experimentally evaluated in mice following two doses of the BNT162b2 vaccine. The SARS-CoV-1-based booster vaccine outperformed other candidates in terms of neutralizing antibody breadth and duration, as well as protective activity against Omicron (BA.2) challenge. This study suggests a unique strategy for selecting booster vaccines based on antigenic distance, which may be useful in designing future booster vaccines as new SARS-CoV-2 variants emerge.

Identification of sucrose synthase from Micractinium conductrix to favor biocatalytic glycosylation.

Sucrose synthase (SuSy, EC 2.4.1.13) is a unique glycosyltransferase (GT) for developing cost-effective glycosylation processes. Up to now, some SuSys derived from plants and bacteria have been used to recycle uridine 5'-diphosphate glucose in the reactions catalyzed by Leloir GTs. In this study, after sequence mining and experimental verification, a SuSy from Micractinium conductrix (McSuSy), a single-cell green alga, was overexpressed in Escherichia coli, and its enzymatic properties were characterized. In the direction of sucrose cleavage, the specific activity of the recombinant McSuSy is 9.39 U/mg at 37°C and pH 7.0, and the optimum temperature and pH were 60°C and pH 7.0, respectively. Its nucleotide preference for uridine 5'-diphosphate (UDP) was similar to plant SuSys, and the enzyme activity remained relatively high when the DMSO concentration below 25%. The mutation of the predicted N-terminal phosphorylation site (S31D) significantly stimulated the activity of McSuSy. When the mutant S31D of McSuSy was applied by coupling the engineered Stevia glycosyltransferase UGT76G1 in a one-pot two-enzyme reaction at 10% DMSO, 50 g/L rebaudioside E was transformed into 51.06 g/L rebaudioside M in 57 h by means of batch feeding, with a yield of 76.48%. This work may reveal the lower eukaryotes as a promising resource for SuSys of industrial interest.

The viral fitness and intrinsic pathogenicity of dominant SARS-CoV-2 Omicron sublineages BA.1, BA.2, and BA.5.

BACKGROUND: Among the Omicron sublineages that have emerged, BA.1, BA.2, BA.5, and their related sublineages have resulted in the largest number of infections. While recent studies demonstrated that all Omicron sublineages robustly escape neutralizing antibody response, it remains unclear on whether these Omicron sublineages share any pattern of evolutionary trajectory on their replication efficiency and intrinsic pathogenicity along the respiratory tract. METHODS: We compared the virological features, replication capacity of dominant Omicron sublineages BA.1, BA.2 and BA.5 in the human nasal epithelium, and characterized their pathogenicity in K18-hACE2, A129, young C57BL/6, and aged C57BL/6 mice. FINDINGS: We found that BA.5 replicated most robustly, followed by BA.2 and BA.1, in the differentiated human nasal epithelium. Consistently, BA.5 infection resulted in higher viral gene copies, infectious viral titres and more abundant viral antigen expression in the nasal turbinates of the infected K18-hACE2 transgenic mice. In contrast, the Omicron sublineages are continuously attenuated in lungs of infected K18-hACE2 and C57BL/6 mice, leading to decreased pathogenicity. Nevertheless, lung manifestations remain severe in Omicron sublineages-infected A129 and aged C57BL/6 mice. INTERPRETATION: Our results suggested that the Omicron sublineages might be gaining intrinsic replication fitness in the upper respiratory tract, therefore highlighting the importance of global surveillance of the emergence of hyper-transmissive Omicron sublineages. On the contrary, replication and intrinsic pathogenicity of Omicron is suggested to be further attenuated in the lower respiratory tract. Effective vaccination and other precautions should be in place to prevent severe infections in the immunocompromised populations at risk. FUNDING: A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.