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1.
J Am Chem Soc ; 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33819019

RESUMO

Single-atom catalysts are often reported to have catalytic properties that surpass those of nanoparticles, while a direct comparison of sites common and different for both is lacking. Here we show that single atoms of Pt-group metals embedded into the surface of Fe3O4 have a greatly enhanced interaction strength with CO2 compared with the Fe3O4 surface. The strong CO2 adsorption on single Rh atoms and corresponding low activation energies lead to 2 orders of magnitude higher conversion rates of CO2 compared to Rh nanoparticles. This high activity of single atoms stems from the partially oxidic state imposed by their coordination to the support. Fe3O4-supported Rh nanoparticles follow the behavior of single atoms for CO2 interaction and reduction, which is attributed to the dominating role of partially oxidic sites at the Fe3O4-Rh interface. Thus, we show a likely common catalytic chemistry for two kinds of materials thought to be different, and we show that single atoms of Pt-group metals on Fe3O4 are especially successful materials for catalyzed reactions that depend primarily upon sites with the metal-O-Fe environment.

2.
J Virol ; 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827945

RESUMO

Immune memory represents the most efficient defense against invasion and transmission of infectious pathogens. In contrast to memory T and B cells, the roles of innate immunity in recall responses remain inconclusive. In this study, we identified a novel mouse spleen NK cell subset expressing NKp46 and NKG2A induced by intranasal influenza virus infection. These memory NK cells specifically recognize N-linked glycosylation sites on influenza hemagglutinin (HA) protein. Different from memory-like NK cells reported previously, these NKp46+NKG2A+ memory NK cells exhibited HA-specific silence of cytotoxicity but increase of IFN-γ response against influenza virus-infected cells, which could be reversed by Pifithrin-µ, a p53-HSP70 signaling inhibitor. During recall responses, splenic NKp46+NKG2A+ NK cells were recruited to infected lung and modulated viral clearance of virus and CD8+ T cell distribution, resulting in improved clinical outcomes. This long-lived NK memory bridges innate and adaptive immune memory response and promotes the homeostasis of local environment during recall response.ImportanceIn this study, we demonstrate a novel HA-specific NKp46+NKG2A+ NK cell subset induced by influenza A virus infection. These memory NK cells show virus-specific decreased cytotoxicity and increased IFN-γ on re-encountering the same influenza virus antigen. In addition, they modulate host recall responses and CD8 T cell distribution, thus bridging the innate immune and adaptive immune responses during influenza virus infection.

3.
Biotechnol Bioeng ; 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33844277

RESUMO

Antibody disulfide bond reduction has been a challenging issue in monoclonal antibody manufacturing. It could lead to decrease of product purity and failure to meet targeted product profile and/or specifications. More importantly, disulfide bond reduction could also impact drug safety and efficacy. Scientists across industry have been examining the root causes and developing mitigation strategies to address the challenge. In recent years, with the development of high titer mammalian cell culture processes to meet the rapidly growing demand for antibody biopharmaceuticals, disulfide bond reduction has been observed more frequently. Thus, it is necessary to continue evolving the disulfide reduction mitigation strategies and developing novel approaches to maintain high product quality. Additionally, in recent years as more complex molecules (such as bispecific and trispecific antibodies) emerge, the molecular heterogeneity due to incomplete formation of the interchain disulfide bonds becomes a more imperative challenging issue. Given the disulfide reduction challenges that biotech industry is facing, in this review, we provide a comprehensive scientific summary of the root cause analysis of disulfide reduction during process development of antibody therapeutics, mitigation strategies and its potential remediated recovery based on published papers. First, this paper intends to highlight different aspects of the root cause for disulfide reduction. Secondly, to provide a broader understanding of the disulfide bond reduction in downstream process, this paper discusses disulfide bond reduction impact on product stability, associated analytical methods for disulfide bond reduction detection and characterization, process control strategies as well as their manufacturing implementation. In addition, brief perspectives on the development of future mitigation strategies are also reviewed, including platform alignment, mitigation strategy application for the emerging new modalities such as bispecific and trispecific antibodies as well as using machine learning to identify molecule susceptibility of disulfide bond reduction. The data in this review are originated from the published papers. This article is protected by copyright. All rights reserved.

4.
Artigo em Inglês | MEDLINE | ID: mdl-33818316

RESUMO

To determine the occurrence of mineral oil hydrocarbons (MOH) in food contact papers in China, and to investigate the potential sources of MOH contamination, a total of 159 food contact papers and raw materials were analysed by off-line solid-phase extraction-gas chromatography flame ionisation detection (SPE-GC-FID) and a GC-MS method. The migration of MOH from food contact papers into Tenax, olive oil or 50% ethanol under the worst foreseeable conditions of use was determined. The results indicated that the occurrence of MOH in China is of a potential health risk concerning the migration of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) which were detected in 82.6% and 50.4% of samples, respectively. Migration of MOSH from 47.9% of samples was higher than 2 mg/kg and migration of MOAH from 32.2% samples exceeded 0.5 mg/kg in case of the worst foreseeable condition of use. The highest mean migration of MOSH and MOAH were found in packaging papers for long-term storage (more than 6 months), with mean migration of 91.2 mg/kg and 1.4 mg/kg, respectively. Migration of MOH from printed paper was considerably higher than that of unprinted paper, validating previous findings that the printing ink is the predominant source of MOH contamination in food contact papers. Migration of MOH from paper bowls used for packing instant noodles was relatively low, suggesting the internal hollow layer may be acting as a functional barrier that could block the transfer of MOH (up to C28) through the gas phrase, even though the outer layer was made from recycled paper. High concentrations of MOSH and MOAH were also detected in de-foamers, adhesives and rosin sizing agents, indicating that the MOH contamination caused by the use of raw materials and additives should also be taken into consideration.

5.
Infect Dis Poverty ; 10(1): 44, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33789759

RESUMO

BACKGROUND: Acute-on-chronic liver failure (ACLF) is characterized by an excessive systemic inflammatory response and organ failure and has high mortality. Bacterial infections (BIs) worsen the clinical course of ACLF and carry a poor prognosis in ACLF patients. The efficacy of third-generation cephalosporins has been challenged in recent years. The aim of this study was to characterize the difference between ACLF patients with and without BIs and to provide a reference for medical intervention. METHODS: A total of 140 patients with hepatitis B virus-related ACLF (HBV-ACLF) hospitalized at the Department of Infectious Diseases, Huashan Hospital, Fudan University (Shanghai, China) between May 2013 and January 2020 were enrolled. Mann-Whitney U test was used to compare the baseline characteristics of HBV-ACLF patients with and without BIs. Univariate and multivariate analyses were performed to find predictors of BIs. The characteristics of BIs and the role of prophylactic antibiotics were profiled. RESULTS: A total of 97 episodes of BIs occurred in patients during the course of HBV-ACLF. Patients with and without BIs differed in clinical characteristics. The incidence of BIs showed a positive correlation with the ACLF grade (P = 0.003) and the clinical course (P = 0.003). The 90-day transplant-free survival of patients with BIs was lower than those without BIs (P < 0.0001). Patients administered prophylactic antibiotics showed a lower incidence of BIs and had a higher transplant-free survival probability than those who did not (P = 0.046). No statistical differences in antibiotic efficacy between third-generation and other antibiotics were observed (P = 0.108). CONCLUSIONS: BIs affected the clinical course and prognosis of patients with HBV-ACLF. Prophylactic antibiotics were of potential clinical importance in the prevention of BIs and improving the clinical course and prognosis in HBV-ACLF patients. Third-generation cephalosporins were qualified for use in antibiotic prophylaxis.

6.
J Pharm Sci ; 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33812889

RESUMO

Size Exclusion Chromatography (SEC) has been widely used to assess aggregate content in bio-pharmaceutical drugs such as monoclonal antibodies (mAbs), and is routinely used during method development and release testing. Electrostatic interactions between protein analytes and SEC column resin are commonly observed besides the primary mode of size separation during SEC method development, which needs to be minimized. An effective method to minimize electrostatic interactions is through increasing mobile phase (MP) salt concentration. However; increasing salt concentration in MP will induce increased hydrophobicity of proteins and increased hydrophobic interactions between protein and stationary phase, as demonstrated for mAb-A in this paper, a protein with high surface aggregation propensity (SAP) score and an isoelectric point near mobile phase pH. In this work, a systematic, Design of Experimental approach was taken to identify optimal SEC method conditions including column type, buffer composition, ionic strength, pH and additives. The optimized method was demonstrated to be robust towards small changes in method operation conditions and was qualified for use in product release and stability studies. Additionally, biophysical and computational studies were performed to elucidate the role of MP additives, which supports the use of arginine as an essential additive to minimize undesirable hydrophobic interactions between proteins and stationary phase.

7.
Biochemistry ; 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33793198

RESUMO

Fluorescent derivatives of the ß-amyloid peptides (Aß) are valuable tools for studying the interactions of Aß with cells. Facile access to labeled expressed Aß offers the promise of Aß with greater sequence and stereochemical integrity, without impurities from amino acid deletion and epimerization. Here, we report methods for the expression of Aß42 with an N-terminal cysteine residue, Aß(C1-42), and its conjugation to generate Aß42 bearing fluorophores or biotin. The methods rely on the hitherto unrecognized observation that expression of the Aß(MC1-42) gene yields the Aß(C1-42) peptide, because the N-terminal methionine is endogenously excised by Escherichia coli. Conjugation of Aß(C1-42) with maleimide-functionalized fluorophores or biotin affords the N-terminally labeled Aß42. The expression affords ∼14 mg of N-terminal cysteine Aß from 1 L of bacterial culture. Subsequent conjugation affords ∼3 mg of labeled Aß from 1 L of bacterial culture with minimal cost for labeling reagents. High-performance liquid chromatography analysis indicates the N-terminal cysteine Aß to be >97% pure and labeled Aß peptides to be 94-97% pure. Biophysical studies show that the labeled Aß peptides behave like unlabeled Aß and suggest that labeling of the N-terminus does not substantially alter the properties of the Aß. We further demonstrate applications of the fluorophore-labeled Aß peptides by using fluorescence microscopy to visualize their interactions with mammalian cells and bacteria. We anticipate that these methods will provide researchers convenient access to useful N-terminally labeled Aß, as well as Aß with an N-terminal cysteine that enables further functionalization.

8.
Micromachines (Basel) ; 12(3)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668404

RESUMO

It is important to characterize surface topography in order to study machined surface characteristics. Due to the features of periodicity and randomness of machined surface topography, the existing topographical parameters may not describe its features accurately. A novel characterization method called the normal declination angle of microfacet-based surface topography is thus proposed for this task. The topography of machined surfaces is measured and the data on the normal declination angle are obtained. Then, surface topography is analyzed via the distribution of the normal declination angle. The lognormal distribution characterization model of machined surface topography is established, and the accuracy of the model is verified by error analysis. The results show that the calculated results of the present characterization model are generally consistent with the distribution of the normal declination angle, where the maximal root mean square errors (RMSE) is 4.5%. Therefore, this study may serve as an effective and novel way to describe the characteristics of the machined surface topography.

9.
J Colloid Interface Sci ; 593: 105-115, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33744521

RESUMO

Although lots of methods have been developed for self-healing materials, it remains a formidable challenge to achieve a thermosetting material with water-insensitive and self-healing properties at room temperature. Nature always provides intelligent strategies for developing advanced materials with superior properties. Herein, a novel self-healable polyurea-urethane was rationally designed by combining mussel adhesive protein-mimetic structure and dynamic aromatic disulfide bonds. It achieves high self-healing efficiency of 98.4% at room temperature for only 6 h and 90% at 60℃ for only 30 min without any external stimuli. Impressively, this self-healing capability possesses exceptional water-resistance, which presents high self-healing efficiency of 98.1% for 2 h and 82.1% for 6 h in 60℃ and 25℃ water, respectively. Besides, the designed polyurea-urethane exhibits excellent mechanical properties such as high elongation at break of 2400%, notch-insensitive stretching elongation of 1500% and notable recovery capability. This strategy shows promising application potential in solid propellants, protective coating, electronic skin, soft sensors and other water-resistant devices.

10.
Cell Death Dis ; 12(4): 314, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33762577

RESUMO

Chemotherapeutic agents have been linked to immunogenic cell death (ICD) induction that is capable of augmenting anti-tumor immune surveillance. The cardiac glycoside oleandrin, which inhibits Na+/K+-ATPase pump (NKP), has been shown to suppress breast cancer growth via inducing apoptosis. In the present study, we showed that oleandrin treatment triggered breast cancer cell ICD by inducing calreticulin (CRT) exposure on cell surface and the release of high-mobility group protein B1 (HMGB1), heat shock protein 70/90 (HSP70/90), and adenosine triphosphate (ATP). The maturation and activation of dendritic cells (DCs) were increased by co-culturing with the oleandrin-treated cancer cells, which subsequently enhanced CD8+ T cell cytotoxicity. Murine breast cancer cell line EMT6 was engrafted into BALB/c mice, and tumor-bearing mice were administered with oleandrin intraperitoneally every day. Oleandrin inhibited tumor growth and increased tumor infiltrating lymphocytes including DCs and T cells. Furthermore, the differential mRNA expression incurred by oleandrin was investigated by mRNA sequencing and subsequently confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Mechanistically, oleandrin induced endoplasmic reticulum (ER) stress-associated, caspase-independent ICD mainly through PERK/elF2α/ATF4/CHOP pathway. Pharmacological and genetic inhibition of protein kinase R-like ER kinase (PERK) suppressed oleandrin-triggered ICD. Taken together, our findings showed that oleandrin triggered ER stress and induced ICD-mediated immune destruction of breast cancer cells. Oleandrin combined with immune checkpoint inhibitors might improve the efficacy of immunotherapy.

11.
J Immunother Cancer ; 9(3)2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33782107

RESUMO

BACKGROUND: Dickkopf 1 (DKK1) is associated with tumor progression. However, whether DKK1 influences the tumor response to programmed cell death protein 1 (PD-1) blockade in colorectal cancers (CRCs) with deficient mismatch repair (dMMR) or microsatellite instability (MSI) has never been clarified. METHODS: Tumor tissues from 80 patients with dMMR CRC were evaluated for DKK1 expression and immune status via immunohistochemistry. Serum DKK1 was measured in another set of 43 patients who received PD-1 blockade therapy. CT26 cells and dMMR CRC organoids were cocultured with T cells, and CT26-grafted BALB/c mice were also constructed. T-cell cytotoxicity was assessed by apoptosis assays and flow cytometry. The pathway through which DKK1 regulates CD8+ T cells was investigated using RNA sequencing, and chromatin immunoprecipitation and luciferase reporter assays were conducted to determine the downstream transcription factors of DKK1. RESULTS: Elevated DKK1 expression was associated with recurrence and decreased CD8+ T-cell infiltration in dMMR CRCs, and patients with high-serum DKK1 had a poor response to PD-1 blockade. RNA interference or neutralization of DKK1 in CRC cells enhanced CD8+ T-cell cytotoxicity, while DKK1 decreased T-bet expression and activated GSK3ß in CD8+ T cells. In addition, E2F1, a downstream transcription factor of GSK3ß, directly upregulated T-bet expression. In organoid models, the proportion of apoptotic cells was elevated after individual neutralization of PD-1 or DKK1 and was further increased on combined neutralization of PD-1 and DKK1. CONCLUSIONS: DKK1 suppressed the antitumor immune reaction through the GSK3ß/E2F1/T-bet axis in CD8+ T cells. Elevated serum DKK1 predicted poor tumor response to PD-1 blockade in dMMR/MSI CRCs, and DKK1 neutralization may restore sensitivity to PD-1 blockade.

12.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(1): 101-108, 2021 Feb 28.
Artigo em Chinês | MEDLINE | ID: mdl-33663670

RESUMO

The application of artificial intelligence in the field of primary health care can effectively improve diagnosis and treatment,avoid over-examination and over-medication,and make up for the shortage of high-quality medical resources in primary medical and health institutions.Focusing on the application of artificial intelligence in the field of primary health care,this paper analyzes the existing application modes and typical cases,studies its main stakeholders,interest demands and problems,and provides corresponding suggestions.

13.
J Org Chem ; 86(7): 5345-5353, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33710879

RESUMO

A facile method for the preparation of 2,3-dialkyl-substituted quinazolinones from readily available N-arylamides and commercial isocyanates was developed. This one-pot procedure involves the chemoselective activation of the secondary amide with Tf2O/2-Br-Pyr, the sequential addition of isocyanate, and cyclization. The mild reaction is general for a wide range of substrates and can be run on a gram scale.

14.
J Thorac Oncol ; 2021 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-33722707

RESUMO

INTRODUCTION: Metastasis is the primary cause of lung cancer-related death. Nevertheless, the underlying molecular mechanisms and evolutionary patterns of lung cancer metastases are still elusive. METHODS: We performed whole-exome sequencing for 40 primary tumors (PTs) and 61 metastases from 47 patients with lung cancer, of which 40 patients had paired PTs and metastases. The PT-metastasis genomic divergence, metastatic drivers, timing of metastatic dissemination, and evolutionary origins were analyzed using appropriate statistical tools and mathematical models. RESULTS: There were various degrees of genomic heterogeneity when comparing the paired primary and metastatic lesions or comparing metastases of different sites. Multiple metastasis-selected/enriched genetic alterations were found, such as MYC amplification, NKX2-1 amplification, RICTOR amplification, arm 20p gain, and arm 11p loss, and these results were were also featured in a meta-analysis cross-validated using an independent cohort from Memorial Sloan-Kettering Cancer Center database. To elucidate the metastatic seeding time, we applied a metastatic model and found 61.1% of the tumors were late dissemination, in which the metastatic seeding happened approximately 2.74 years before clinical detection. One exception was lymph node metastases whose dissemination time was relatively early. By analyzing the evolutionary origins, we reported that nonlymph node metastases were mainly seeded by the PT (87.5%) rather than the earlier colonized lymph node metastases. CONCLUSIONS: Our results shed light on the molecular features that potentially drive lung cancer metastases. The distinct temporospatial pattern of disease progression revealed that lung cancer was susceptible to either late dissemination or indolent early lymph node metastases, leaving a potential time window to minimize metastases by early cancer detection.

15.
J Biomed Nanotechnol ; 17(2): 230-241, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33785094

RESUMO

As a conventional complication of sepsis, acute kidney injury (AKI) is characterized by high incidence and mortality. Effective management methods are still lacking. Quercetin belongs to a kind of flavonoids that exerts many functions, for example anti-inflammation and anti-fibrosis. However, its function in sepsis AKI is uncertain. Our study therefore set out to assess the function of quercetin in AKI mice model induced by lipopolysaccharide (LPS) and human proximal tubular cells (HK-2), including the potential mechanisms. Quercetin was loaded onto a biodegradable polymer carrier (nanoparticle) to enhance its bioavailability. The data showed that quercetin administration strikingly improved renal dysfunction and ameliorated tubular injury caused by LPS in mice. In mice model and in cultured cells, quercetin pretreatment obviously restrained LPS-triggered cell apoptosis and inflammation, including generation of various cytokines. Moreover, the results from mice model and cell model showed that quercetin could diminish IκBα and p65 phosphorylation after LPS treatment. The most significant observation of this study was that quercetin elevated the expression of Sirt1. Transfection of Sirt1 specific shRNA mitigated the suppression of quercetin on cell apoptosis, inflammation and of NF-κB activation triggered by LPS. Therefore, these sequels indicate that quercetin protects against sepsis-associated AKI by upregulation Sirt1 expression through quenching NF-κB activation and may be an encouraging therapeutic agent for patients with sepsis-associated AKI.


Assuntos
NF-kappa B , Nanopartículas , Animais , Humanos , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Quercetina/farmacologia , Sirtuína 1
16.
J Chromatogr A ; 1643: 462008, 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33780880

RESUMO

Charge variants of biological products, such as monoclonal antibodies (mAbs), often play an important role in stability and biological activity. Characterization of these charge variants is challenging, however, primarily due to the lack of both efficient and effective isolation methods. In this work, we present a novel use of an established, high productivity continuous chromatography method, known as multi-column counter-current solvent gradient purification (MCSGP), to create an enriched product that can be better utilized for analytical characterization. We demonstrate the principle of this separation method and compare it to traditional batch HPLC (high performance liquid chromatography) or FPLC (fast protein liquid chromatography) methods, using the isolation of charge variants of different mAbs as a case study. In a majority of cases, we are able to show that the MCSGP method is able to provide enhanced purity and quantity of samples when compared to traditional fractionation methods, using the same separation conditions. In one such case, a sample prepared by MCSGP methodology achieved 95% purity in 10 hours of processing time, while those prepared by FPLC and HPLC achieved purities of 78% and 87% in 48 and 300 hours of processing time, respectively. We further evaluate charge variant enrichment strategies using both salt and pH gradients on cation exchange chromatography (CEX) and anion exchange chromatography (AEX) resins, to provide more effective separation and less sample processing following enrichment. As a result, we find that we are able to utilize different gradients to change the enrichment capabilities of certain charged species. Lastly, we summarize the identified mAb charge variants used in this work, and highlight benefits to analytical characterization of charge variants enriched with the continuous chromatography method. The method adds a new option for charge variant enrichment and facilitates analytical characterization of charge variants.

17.
Arch Gynecol Obstet ; 2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33547934

RESUMO

PURPOSE: To detect the methylation of Dickkopf-associated protein 1 (DKK-1) gene promoter in cervical exfoliated cells and to study its clinical significance in cervical squamous cell carcinoma (CSCC) and its relationship with high-risk HPV infection. METHODS: Methylation-specific PCR (MSP) was utilized to detect the methylation of DKK-1 gene promoter in cervical exfoliated cells from 40 patients with CSCC and 40 patients with chronic cervicitis in the Affiliated Hospital of Inner Mongolia Medical University. The methylation rate of DKK-1 gene promoter in different clinicopathological factors and its relationship with high-risk HPV infection was compared, and different detection methods were compared. RESULT: The degree of methylation of DKK-1 gene promoter in CSCC group was significantly higher than that in cervicitis group (P < 0.05). In CSCC group, the degree of methylation was significantly different in high-risk HPV infection, histological differentiation, tumor size, lymph node metastasis and the International Federation of Gynecology and Obstetrics (FIGO) staging (all P < 0.05). The degree of methylation is not related to the type of high-risk HPV infection (P > 0.05). The one-year survival rate of CSCC patients with high-risk HPV positive and DKK-1 gene promoter methylation is relatively low, only 74.1%. The sensitivity, specificity and accuracy of DKK-1 gene methylation combined with high-risk HPV detection were 96.7%, 78.0% and 85.0%, respectively. CONCLUSION: Methylation of DKK-1 gene promoter in cervical exfoliated cells of patients with CSCC is related to high-risk HPV infection and different clinicopathological factors, but the degree of methylation of DKK-1 gene is not related to the type of high-risk HPV infection. It may become an indicator different from HPV typing detection, which may play a shunt role in suggesting whether further invasive cervical examination is needed and reduce cervical invasive examination and overtreatment. It may be related to the survival rate of patients, which can be used to estimate the development and prognosis of CSCC and may play a good role in early warning in follow-up monitoring of CSCC after treatment. DKK1 gene methylation combined with HPV detection can improve the sensitivity, specificity and accuracy of diagnosis, which may improve the detection rate of early CSCC and make up for the deficiency of HPV and TCT detection. That may become a non-invasive screening method for CSCC.

18.
Anal Bioanal Chem ; 413(8): 2113-2123, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33543314

RESUMO

Isomerization of aspartic acid (Asp) in therapeutic proteins could lead to safety and efficacy concerns. Thus, accurate quantitation of various Asp isomerization along with kinetic understanding of the variant formations is needed to ensure optimal process development and sufficient product quality control. In this study, we first observed Asp-succinimide conversion in complementarity-determining regions (CDRs) Asp-Gly motif of a recombinant mAb through ion exchange chromatography, intact protein analysis by mass spectrometry, and LC-MS/MS. Then, we developed a specific peptide mapping method, with optimized sample digestion conditions, to accurately quantitate Asp-succinimide-isoAsp variants at peptide level without method-induced isomerization. Various kinetics of Asp-succinimide-isoAsp isomerization pathways were elucidated using 18O labeling followed by LC-MS analysis. Molecular modeling and molecular dynamic simulation provide additional insight on the kinetics of Asp-succinimide formation and stability of succinimide intermediate. Findings of this work shed light on the molecular construct and the kinetics of the formation of isoAsp and succinimide in peptides and proteins, which facilitates analytical method development, protein engineering, and late phase development for commercialization of therapeutic proteins.

19.
Biotechnol Bioeng ; 2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33624836

RESUMO

The goal of cell culture process intensification is to improve productivity while maintaining acceptable quality attributes. In this report, four processes, namely a conventional manufacturing Process A, and processes intensified by enriched N-1 seed (Process B), by perfusion N-1 seed (Process C), and by perfusion production (Process D) were developed for the production of a monoclonal antibody. The three intensified processes substantially improved productivity, however, the product either failed to meet the specification for charge variant species (main peak) for Process D or the production process required early harvest to meet the specification for charge variant species, Day 10 or Day 6 for Processes B and C, respectively. The lower main peak for the intensified processes was due to higher basic species resulting from higher C-terminal lysine. To resolve this product quality issue, we developed an enzyme treatment method by introducing carboxypeptidase B (CpB) to clip the C-terminal lysine, leading to significantly increased main peak and an acceptable and more homogenous product quality for all the intensified processes. Additionally, Processes B and C with CpB treatment extended bioreactor durations to Day 14 increasing titer by 38% and 108%, respectively. This simple yet effective enzyme treatment strategy could be applicable to other processes that have similar product quality issues.

20.
PLoS One ; 16(2): e0232918, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33600466

RESUMO

To determine the expression profile and clinical significance of long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) of patients with primary gout and healthy control subjects. Human lncRNA microarrays were used to identify the differentially expressed lncRNAs and mRNAs in primary gout patients (n = 6) and healthy control subjects (n = 6). Bioinformatics analyses were performed to predict the roles of differently expressed lncRNAs and mRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of 8 lnRNAs in 64 primary gout patients and 32 healthy control subjects. Spearman's correlation was used to analyze the correlation between these eight lncRNAs and the laboratory values of gout patients. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic value of the lncRNAs identified in gout. The microarray analysis identified 1479 differentially expressed lncRNAs (879 more highly expressed and 600 more lowly expressed), 862 differentially expressed mRNAs (390 more highly expressed and 472 more lowly expressed) in primary gout (fold change > 2, P < 0.05), respectively. The bioinformatic analysis indicated that the differentially expressed lncRNAs regulated the abnormally expressed mRNAs, which were involved in the pathogenesis of gout through several different pathways. The expression levels of TCONS_00004393 and ENST00000566457 were significantly increased in the acute gout flare group than those in the intercritical gout group or healthy subjects (P<0.01). Moreover, inflammation indicators were positive correlated with TCONS_00004393 and ENST00000566457 expression levels. The areas under the ROC curve of ENST00000566457 and NR-026756 were 0.868 and 0.948, respectively. Our results provide novel insight into the mechanisms of primary gout, and reveal that TCONS_00004393 and ENST00000566457 might be as candidate targets for the treatment of gout flare; ENST00000566457 and NR-026756 could effectively discriminate between the gout and the healthy control groups.

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