Chinese Hamster Ovary Research Articles

Indirect effects of interference of two emerging environmental contaminants on cell health: Radiofrequency radiation and gold nanoparticles

BackgroundThe global need for wireless technologies is growing rapidly. So, we have been exposed to a new type of environmental pollution: radiofrequency radiation (RFR). Recent studies have shown that RFR can cause not only direct effects but also indirect or non-targeted effects such as the bystander effect (BE). In this study, we investigated the BE induced by RFR in the present of gold nanoparticles (GNP). Moreover, we studied the expression of cyclooxygenase-2 (COX-2). MethodsNon-toxic dose of 15-nm GNP was used to treat the Chinese Hamster Ovary (CHO) cells. After 48 h of incubation, cells were exposed to 900 MHz GSM RFR for 24 h. Then we collected the cell culture medium of these cells (conditioned culture medium, CCM) and transferred it to new cells (bystander cells). Cell deaths, DNA breaks, oxidative stress and COX-2 expression were analyzed in all groups. ResultsThe results showed that RFR increased metabolic death in cells treated with GNP. Inversely, the colony formation ability was reduced in bystander cells and RFR exposed cells either in the presence or absence of GNP. Also, the level of reactive oxygen species (ROS) in GNP treated cells showed a significant reduction compared to those of untreated cells. However, RFR-induced DNA breaks and the frequencies of micronuclei (MN) were not significantly affected by GNP. The expression of COX-2 mRNA increased in RFR GNP treated cells, but the difference was not significant. ConclusionOur results for the first time indicated that RFR induce indirect effects in the presence of GNP. However, the molecular mediators of these effects differ from those in the absence of GNP. Also, to our knowledge, this is the first study to show that COX-2 is not involved in the bystander effect induced by 900 MHz RFR.

Targeted delivery of elesclomol using a magnetic mesoporous platform improves prostate cancer treatment both in vitro and in vivo

BackgroundTo improve the anticancer properties of elesclomol (ELC), targeted theranostic nanoparticles (NPs; APT-PEG-Au-MMNPs@ELC) were designed to increase the selectivity of the drug delivery system (DDS). Materials and methodsELC was synthesized and entrapped in the open porous structure of magnetic mesoporous silica nanoparticles (MMNPs). The pore entrance of MMNPs was then blocked using gold gatekeepers. Finally, the external surfaces of the particles were grafted with functional polyethylene glycol (PEG) and EpCAM aptamer to generate biocompatible and targeted NPs. In the next step, the physicochemical properties of prepared NPs were fully evaluated and their anticancer potential was evaluated both in vitro and in vivo. ResultsThe targeted NPs were successfully synthesized with a final size diameter of 81.13 ± 7.41 nm. The results indicated a pH-dependent release pattern, which sustained for 72 h despite an initial rapid release. Upon exposure to APT-PEG-Au-MMNPs@ELC, higher cytotoxicity was observed in human prostate cancer cells (PC-3) as compared with control Chinese hamster ovary (CHO) cells, indicating higher specificity of targeted NPs against EpCAM-positive cancerous cells. Moreover, APT-PEG-Au-MMNPs@ELC could induce apoptosis in PC-3 cells. In vivo results on a PC-3 xenograft tumor model demonstrated that targeted NPs could significantly inhibit tumor growth and diminish severe side effects of ELC, compared to the free drug. ConclusionCollectively, APT-PEG-Au-MMNPs@ELC could be considered a promising theranostic platform for the targeted delivery of ELC to improve its therapeutic effects in prostate cancer.

RNA Aptamer-Mediated Gene Activation Systems for Inducible Transgene Expression in Animal Cells.

RNA expression analyses can be used to obtain various information from inside cells, such as physical conditions, the chemical environment, and endogenous signals. For detecting RNA, the system regulating intracellular gene expression has the potential for monitoring RNA expression levels in real time within living cells. Synthetic biology provides powerful tools for detecting and analyzing RNA inside cells. Here, we devised an RNA aptamer-mediated gene activation system, RAMGA, to induce RNA-triggered gene expression activation by employing an inducible complex formation strategy grounded in synthetic biology. This methodology connects DNA-binding domains and transactivators through target RNA using RNA-binding domains, including phage coat proteins. MS2 bacteriophage coat protein fused with a transcriptional activator and PP7 bacteriophage coat protein fused with the tetracycline repressor (tetR) can be bridged by target RNA encoding MS2 and PP7 stem-loops, resulting in transcriptional activation. We generated recombinant CHO cells containing an inducible GFP expression module governed by a minimal promoter with a tetR-responsive element. Cells carrying the trigger RNA exhibited robust reporter gene expression, whereas cells lacking it exhibited no expression. GFP expression was upregulated over 200-fold compared with that in cells without a target RNA expression vector. Moreover, this system can detect the expression of mRNA tagged with aptamer tags and modulate reporter gene expression based on the target mRNA level without affecting the expression of the original mRNA-encoding gene. The RNA-triggered gene expression systems developed in this study have potential as a new platform for establishing gene circuits, evaluating endogenous gene expression, and developing novel RNA detectors.

Crystal structures of human immune protein FIBCD1 suggest an extended binding site compatible with recognition of pathogen-associated carbohydrate motifs

Fibrinogen C-domain containing-1 (FIBCD1) is an immune protein proposed to be involved in host recognition of chitin on the surface of pathogens. As FIBCD1 readily binds to acetylated molecules, we have determined the high-resolution crystal structures of a recombinant fragment of the FIBCD1 C-terminal domain complexed with small N-acetyl-containing ligands to determine the mode of recognition. All ligands bind at the conserved N-acetyl binding site (S1) with galactose and glucose-derived ligands rotated 180⁰ with respect to each other. One subunit of a native structure derived from protein expressed in mammalian CHO cells binds glycosylation from a neighbouring subunit, in an extended binding site. Across the various structures, the primary S1 binding pocket is occupied by N-acetyl-containing ligands or acetate, with N-acetyl, acetate or a sulfate ion in an adjacent pocket S1(2). Inhibition binding studies of N-acetylglucosamine oligomers, (GlcNAc)n, n=1,2,3,5,11, via ELISA along with Microscale Thermophoresis affinity assays indicate a strong preference of FIBCD1 for longer N-acetylchitooligosaccharides. Binding studies of mutant H396A, located beyond the S1(2) site, showed no significant difference to wildtype but K381L, within the S1(2) pocket, blocked binding to the model ligand acetylated bovine serum albumin suggesting that this pocket may have functional importance in FIBCD1 ligand binding. The binding studies, alongside structural definition of diverse N-acetyl monosaccharide binding in the primary S1 pocket and of additional, adjacent binding pockets, able to accommodate both carbohydrate and sulfate functional groups, suggests a versatility in FIBCD1 to recognise chitin oligomers and other pathogen-associated carbohydrate motifs across an extended surface.

Comprehensive modeling of cell culture profile using Raman spectroscopy and machine learning

Chinese hamster ovary (CHO) cells are widely utilized in the production of antibody drugs. To ensure the production of large quantities of antibodies that meet the required specifications, it is crucial to monitor and control the levels of metabolites comprehensively during CHO cell culture. In recent years, continuous analysis methods employing on-line/in-line techniques using Raman spectroscopy have attracted attention. While these analytical methods can nondestructively monitor culture data, constructing a highly accurate measurement model for numerous components is time-consuming, making it challenging to implement in the rapid research and development of pharmaceutical manufacturing processes. In this study, we developed a comprehensive, simple, and automated method for constructing a Raman model of various components measured by LC–MS and other techniques using machine learning with Python. Preprocessing and spectral-range optimization of data for model construction (partial least square (PLS) regression) were automated and accelerated using Bayes optimization. Subsequently, models were constructed for each component using various model construction techniques, including linear regression, ridge regression, XGBoost, and neural network. This enabled the model accuracy to be improved compared with PLS regression. This automated approach allows continuous monitoring of various parameters for over 100 components, facilitating process optimization and process monitoring of CHO cells.

Potentially Pathogenic SORL1 Mutations Observed in Autosomal-Dominant Cases of Alzheimer's Disease Do Not Modulate APP Physiopathological Processing.

The SORL1 gene encodes LR11/SorLA, a protein that binds β-amyloid precursor protein (APP) and drives its intracellular trafficking. SORL1 mutations, occurring frequently in a subset of familial cases of Alzheimer's disease (AD), have been documented, but their pathogenic potential is not yet clear and questions remain concerning their putative influence on the physiopathological processing of APP. We have assessed the influence of two SORL1 mutations that were described as likely disease-causing and that were associated with either benign (SorLA924) or severe (SorLA511) AD phenotypes. We examined the influence of wild-type and mutants SorLA in transiently transfected HEK293 cells expressing either wild-type or Swedish mutated APP on APP expression, secreted Aβ and sAPPα levels, intracellular Aβ 40 and Aβ42 peptides, APP-CTFs (C99 and C83) expressions, α-, β- and γ-secretases expressions and activities as well as Aβ and CTFs-degrading enzymes. These paradigms were studied in control conditions or after pharmacological proteasomal modulation. We also established stably transfected CHO cells expressing wild-type SorLA and established the colocalization of APP and either wild-type or mutant SorLA. SorLA mutations partially disrupt co-localization of wild-type sorLA with APP. Overall, although we mostly confirmed previous data concerning the influence of wild-type SorLA on APP processing, we were unable to evidence significant alterations triggered by our set of SorLA mutants, whatever the cells or pharmacological conditions examined. Our study , however, does not rule out the possibility that other AD-linked SORL1 mutations could indeed affect APP processing, and that pathogenic mutations examined in the present study could interfere with other cellular pathways/triggers in AD.

Effective and safe transfer of maternal antibodies persisting two months postpartum following maternal immunization with different doses of recombinant pertussis-containing vaccines

IntroductionRecombinant acellular pertussis (ap) vaccines containing genetically inactivated pertussis toxin (PTgen) and filamentous hemagglutinin (FHA) with or without tetanus (TT) and diphtheria (DT) vaccines (Td) were found safe and immunogenic in non-pregnant and pregnant women. We report here maternal antibody transfer and safety data in mothers and neonates. MethodsThis is the follow up of a phase 2 trial in 2019 among 400 pregnant women who randomly received one dose of recombinant pertussis-only vaccine containing 1 µg PTgen and 1 µg FHA (ap1gen), or Td combined with ap1gen (Tdap1gen), or with 2 µg PTgen and 5 µg FHA (Tdap2gen), or with 5 µg PTgen and 5 µg FHA (TdaP5gen, Boostagen®, BioNet, Thailand) or chemically-inactivated acellular pertussis comparator (Tdap8chem, Boostrix™, GSK, Belgium), either in the second or third trimester of gestation. IgG against PT, FHA, TT and DT were assessed by ELISA, PT-neutralizing antibodies (PTNA) by Chinese Hamster Ovary cell assay and safety outcomes at delivery in mothers and at birth. ResultsAnti-PT and anti-FHA geometric mean concentration (GMC) ratio between infants at birth and mothers at delivery was above 1 in all groups. PT GMC in infants at birth were ≥30 IU/mL in all groups with the highest titers in infants found in TdaP5gen group at birth (118.8 [95% CI 93.9–150.4]). At 2 months, PT GMC ratio to Tdap8chem (98.75% CI) was significantly higher for TdaP5gen (2.6 [1.7–4.0]) and comparable for other recombinant vaccines. No difference in PTNA titers at birth was observed between all groups nor between time of vaccination. Adverse events were comparable in all vaccine groups. ConclusionsBioNet licensed (TdaP5gen and Tdap2gen) and candidate vaccines (Tdap1gen and ap1gen) when given to pregnant women in the second or third trimester of gestation are safe and have induced passive pertussis immunity to infants.

Deep learning-based image analysis for in situ microscopic imaging of cell culture process

Mammalian cell culture is an important bioprocess that directly affects the quality and yield of biopharmaceuticals. Traditionally, condition monitoring of the operation is based on sampling periodically and off-line analysis, which is labor intensive, time consuming, and causing time delays. In this work, in situ microscope is investigated for on-line real-time monitoring of the culture process of Chinese hamster ovary cells with focus on investigation of deep learning-based Mask R-CNN algorithm for image analysis. The model is trained by 184 images with 183,040 cells using data augmentation methods and transfer learning technique. Mask R-CNN segmented the clustered cells more effectively than the conventional one combining edge detection, intensity thresholding, and advanced watershed method as well as the multi-scale edge detection method. Its Dice score, accuracy, precision, sensitivity, F1 score, specificity, and relative volume difference reach 0.862, 0.945, 0.901, 0.827, 0.862, 0.977, and 0.082, respectively. The evolution of geometrical features of cells were further analyzed, including equivalent diameter, circularity, aspect ratio, and eccentricity. The result demonstrated the great potential of deep learning technology in analysis of on-line images for optimization and control of the cell culture process.

Prediction of CHO cell line stability using expression of DNA repair genes.

Chinese hamster ovary (CHO) cells are essential to biopharmaceutical manufacturing and production instability, the loss of productivity over time, is a long-standing challenge in the industry. Accurate prediction of cell line stability could enable efficient screening to identify clones suitable for manufacturing saving significant time and costs. DNA repair genes may offer biomarkers to address this need. In this study, over 40 cell lines representing various host lineages from three companies/organizations were evaluated for expression of five DNA repair genes (Fam35a, Lig4, Palb2, Pari, and Xrcc6). Expression measured in cells with less than 30 population doubling levels (PDLs) was correlated to stability profiles at 60+ PDL. Principal component analysis identified markers which separate stable and unstable CHO-DG44 cell lines. Notably, two genes, Lig4 and Xrcc6, showed higher expression in unstable CHO-DG44 cell lines with copy number loss identified as the mechanism of production instability. Expression levels across all cell ages showed lower DNA repair gene expression was associated with increased cell age. Collectively, DNA repair genes provide critical insight into long-term behavior of CHO cells and their expression levels have potential to predict cell line stability in certain cases.

Alzheimer’s disease‐associated post‐translational modifications of tau influence tau propagation

AbstractBackgroundIn Alzheimer’s disease (AD), tau accumulates with a stereotyped progressive involvement of brain regions. The cellular mechanism for this is the neuron‐to‐neuron propagation of tau, but the factors that influence tau propagation are not fully understood. We hypothesize that AD‐associated post‐translational modifications (PTMs) of tau reduce its propagation since lysines are critical for LRP1‐mediated tau uptake.MethodA construct was designed to model tau propagation in Chinese hamster ovary (CHO) cells and allow identification of donor and recipient cells by immunocytochemistry and flow cytometry. In addition to the wildtype (WT) tau sequence, constructs were made with pseudophosphorylation and pseudoacetylation mutations corresponding to the phosphorylations and acetylations found on low molecular weight (LMW) and high molecular weight (HMW) tau species in AD brains. Additionally, individual PTM mimic mutations corresponding to PTMs of the LMW tau species were made. The constructs were transfected into CHO cells and tau propagation was assessed by flow cytometry after 48 hours. Statistical analysis was performed by ANOVA with adjustment for multiple comparisons.ResultTau propagation using this cell culture model was demonstrated by immunocytochemistry and flow cytometry. Comparison of the WT, LMW‐mimic (8D2Q mutant), and HMW‐mimic (20D3Q mutant) tau propagation constructs revealed that the 8D2Q and 20D3Q mutants displayed reduced tau propagation compared to WT by 23.7% (p = 0.0186) and 26.5% (p = 0.0087), respectively. Comparing the ten single mutant constructs to WT, T181D and T231D showed increased tau propagation by 20.3% (p = 0.0002) and 15.9% (p = 0.0094), respectively. Compared to WT, T217D, K281Q, K353Q, and S404D showed reduced tau propagation by 17.3% (p = 0.0030), 15.3% (p = 0.0123), 23.7% (p <0.0001), and 16.6% (p = 0.0046), respectively.ConclusionThe mimics of AD‐associated tau PTMs found on LMW and HMW tau reduce tau propagation, consistent with the initial hypothesis. The impact of individual PTM mimics on tau propagation is variable, but notably both pseudoacetylation mimics reduce propagation, possibly due to lower affinity with LRP1. Understanding how AD‐associated tau PTMs impact tau propagation may suggest novel targets to slow the progression of AD pathology.

Screening Alzheimer’s genetic risk factors against amyloid‐βeta synaptotoxicity

AbstractBackgroundSynapse degeneration is one of the earliest events in Alzheimer’s disease (AD) and toxic oligomers of amyloid‐beta (Aβ) peptide, cleavage product of APP, plays a major role in this process. Genome‐wide association studies recently reported 75 genomic risk loci for developing AD, but how the potential risk genes contribute to AD remains unknown. This project aims to identify AD genetic risk factors that mediate Aβ‐induced synaptotoxicity.MethodWe conducted a high‐content shRNA screening to assess the impact of ca. 200 AD risk genes on synaptic density and connectivity. Twenty‐four genes expressed in neurons with highest impact on synapses when silenced were shortlisted for a medium‐throughput screening to assess their capacity to block Aβ‐induced synaptotoxicity. Synaptotoxicity was modelled in microfluidic devices that allow primary postnatal rat neurons to be co‐cultured with Chinese hamster ovary cells, that overexpress wild‐type APP or APP with V717I (or London) mutation with increased secretion of Aβ1‐42 oligomers. Microfluidic devices allow the fluidic isolation of neurites from neuronal cell bodies and therefore provide exclusive access to pre‐ and post‐synaptic neurons. Target genes expression will be modulated either in pre‐ or post‐synaptic neurons and its impact on synaptic connectivity will be assessed.ResultBased on the shRNA screening, we shortlisted 17 detrimental genes, for which we obtained overexpression vectors packed in lentiviruses, and 6 protective genes. We have developed a medium‐throughput co‐culture device that permits screening twelve genes per imaging session using the INCell 6000 automated microscope, as well as an automated image analysis workflow for detecting and assigning presynaptic to postsynaptic puncta based on their relative proximity. Gene expression modulation is validated and the screen is on‐going.ConclusionWe have developed a microfluidic co‐culture model to rapidly and systematically interrogate genetic risk factors for their impact on synaptic connectivity. This study will help us identify AD genetic risk factors with a potential to block Aβ‐induced synaptotoxicity in vitro. Hit genes will be functionally validated via microelectrode array recordings.

Anti‐mouse CD98hc nanobodies for brain delivery of a therapeutic moiety

AbstractBackgroundThe blood‐brain barrier (BBB) limits the therapeutic perspective for central nervous system (CNS) disorders such as Alzheimer’s disease. Interestingly, monoclonal antibodies generated against receptor‐mediated transcytosis receptors are able to transport therapeutic proteins across the BBB. Nanobodies, which are the variable domain isolated from camelid heavy‐chain only antibodies have also shown their potential to deliver therapeutics into the CNS. Here we aimed to expand the panel of nanobodies targeting other brain endothelial cell receptors.MethodCamelids were immunized with a pool of DNA encoding for several brain endothelial cell receptors. One target was chosen to validate the immunization and discovery approach, CD98hc, previously suggested to allow drug shuttling across the BBB. Nanobody libraries were selected on Chinese Hamster Ovarian (CHO) cells overexpressing the target of interest. Selected nanobodies were screened in vivo based on their potential to deliver into the CNS either a biologically active neuropeptide neurotensin to reduce body temperature, or a BACE1 inhibiting antibody that reduces the accumulation of Aβ1‐40 species.ResultDNA immunization followed by selections on CHO cells overexpressing the target of interest resulted in specific anti‐mouse CD98hc binders with affinities in the low nanomolar range. In vivo screening of mouse CD98hc nanobody binders revealed some discrepancy between the two methods used. Whereas none of the tested nanobodies fused to neurotensin was able to reduce body temperature, nanobodies fused to the anti‐BACE1 antibody 1A11 effectively reduced Aβ1‐40 levels in the brain. We suggest that the neurotensin approach, although having shown robustness with anti‐TfR nanobodies, might lack sensitivity when screening non‐TfR binders. We suggest BACE1 inhibition as a more robust model to validate CD98hc‐mediated transport across the BBB.ConclusionThis is a proof of concept study in which we have optimized our nanobody discovery approach to find nanobodies against BBB targets, and validated CD98hc as a receptor to target in order to shuttle drugs into the brain. In the future we will explore whether nanobodies raised against novel brain endothelial cell receptors could also improve brain penetration of biologics.

OP38 Evaluation Of A High-Cost Medicine For A Rare Disease: 16-Year Cohort Of Imiglucerase Use For Gaucher Disease In Brazil

IntroductionGaucher disease is a lysosomal storage disease of autosomal recessive inheritance that is caused by a deficiency of the enzyme glucocerebrosidase. This deficiency results in accumulation of the enzyme’s main substrate in the lysosomes of macrophages, mainly in the spleen, liver, and bone marrow. In more severe cases it can affect the lung, kidneys, and central nervous system. There are two main treatments available for patients with Gaucher disease: enzyme replacement therapy and inhibition of substrate synthesis. The main enzyme replacement therapy used in Brazil is imiglucerase, an analog of the human β-glucocerebrosidase enzyme. Imiglucerase is produced by recombinant DNA technology using a cell culture derived from the Chinese hamster ovary. It has 497 amino acids and differs from the endogenous enzyme by an amino acid at position 495, where histidine is replaced by arginine. The objective of the study was to analyze the survival of patients treated for Gaucher disease with imiglucerase in Brazil from 2000 to 2015.MethodsWe constructed a retrospective cohort study of patients with Gaucher disease who received imiglucerase through the Brazilian National Health System from 2000 to 2015 using a national database created from the linkage of administrative databases.ResultsA total of 1,241 patients who received imiglucerase were included. The overall survival rates at one, ten, and 15 years were 98.7 percent (95% confidence interval [CI]: 98.1, 99.4), 92.3 percent (95% CI: 90.2, 94.4), and 89.4 percent (95% CI: 85.6, 93.3), respectively.ConclusionsOur findings advance the understanding of the profile, survival, and risk factors of people with Gaucher disease, adding new data to the discussion regarding pharmaceutical therapies and patient care, and providing data for the development of new public health policies for the use of advanced, high-cost drugs for rare diseases.

New mechanistic insights into halogen-dependent cytotoxic pattern of monohaloacetamide disinfection byproducts

As highly toxic nitrogenous disinfection byproducts (DBPs), monohaloacetamides (monoHAcAms) generally exhibited a cytotoxic rank order of iodoacetamide ˃ bromoacetamide ˃ chloroacetamide. However, the mechanisms underlying the halogen-dependent cytotoxic pattern remain largely veiled as yet. In this work, oxidative stress/damage levels in monoHAcAm-treated Chinese hamster ovary cells were thoroughly analyzed, and binding interactions between monoHAcAms and antioxidative enzyme Cu/Zn-superoxide dismutase (Cu/Zn-SOD) were investigated by multiple spectroscopic techniques and molecular docking. Upon exposure to monoHAcAms, the intracellular levels of key biomarkers associated with oxidative stress/damage, including reactive oxygen species, malondialdehyde, lactate dehydrogenase, 8-hydroxy-2-deoxyguanosine, cell apoptosis, and G1 cell cycle arrest, were all significantly increased in a dose-response manner with the same halogen-dependent rank order as their cytotoxicity. Moreover, this rank order was also determined to be applicable to the monoHAcAm-induced alterations in the conformation, secondary structure, and activity of Cu/Zn-SOD, the microenvironment surrounding aromatic amino acid residues in Cu/Zn-SOD, as well as the predicted binding energy of SOD-monoHAcAm interactions. Our results revealed that the halogen-dependent cytotoxic pattern of monoHAcAms was attributed to their differential capacity to induce oxidative stress/damage and their interaction with antioxidative enzyme, which contribute to a better understanding of the halogenated DBP-induced toxicological mechanisms.

Erratum to: Utilization of Glucocorticoids as Additives for Enhanced Sialylation of Fc-fusion Protein in CHO Cell Cultures

Erratum to: Utilization of Glucocorticoids as Additives for Enhanced Sialylation of Fc-fusion Protein in CHO Cell Cultures

Knockout of BAX and BAK1 Genes and Overexpression of BCL2, BECN1 Genes Increase Lifespan and the Maximum Density of a CHO-S Cell Culture

Knockout of BAX and BAK1 Genes and Overexpression of BCL2, BECN1 Genes Increase Lifespan and the Maximum Density of a CHO-S Cell Culture

Extracellular vesicle-derived silk fibroin nanoparticles loaded with MFGE8 accelerate skin ulcer healing by targeting the vascular endothelial cells

BackgroundReduced supplies of oxygen and nutrients caused by vascular injury lead to difficult-to-heal pressure ulcers (PU) in clinical practice. Rapid vascular repair in the skin wound is the key to the resolution of this challenge, but clinical measures are still limited. We described the beneficial effects of extracellular vesicle-derived silk fibroin nanoparticles (NPs) loaded with milk fat globule EGF factor 8 (MFGE8) on accelerating skin blood vessel and PU healing by targeting CD13 in the vascular endothelial cells (VECs).MethodsCD13, the specific targeting protein of NGR, and MFGE8, an inhibitor of ferroptosis, were detected in VECs and PU tissues. Then, NPs were synthesized via silk fibroin, and MFGE8-coated NPs (NPs@MFGE8) were assembled via loading purified protein MFGE8 produced by Chinese hamster ovary cells. Lentivirus was used to over-express MFGE8 in VECs and obtained MFGE8-engineered extracellular vesicles (EVs-MFGE8) secreted by these VECs. The inhibitory effect of EVs-MFGE8 or NPs@MFGE8 on ferroptosis was detected in vitro. The NGR peptide cross-linked with NPs@MFGE8 was assembled into NGR-NPs@MFGE8. Collagen and silk fibroin were used to synthesize the silk fibroin/collagen hydrogel. After being loaded with NGR-NPs@MFGE8, silk fibroin/collagen hydrogel sustained-release carrier was synthesized to investigate the repair effect on PU in vivo.ResultsMFGE8 was decreased, and CD13 was increased in PU tissues. Similar to the effect of EVs-MFGE8 on inhibiting ferroptosis, NPs@MFGE8 could inhibit the mitochondrial autophagy-induced ferroptosis of VECs. Compared with the hydrogels loaded with NPs or NPs@MFGE8, the hydrogels loaded with NGR-NPs@MFGE8 consistently released NGR-NPs@MFGE8 targeting CD13 in VECs, thereby inhibiting mitochondrial autophagy and ferroptosis caused by hypoxia and accelerating wound healing effectively in rats.ConclusionsThe silk fibroin/collagen hydrogel sustained-release carrier loaded with NGR-NPs@MFGE8 was of great significance to use as a wound dressing to inhibit the ferroptosis of VECs by targeting CD13 in PU tissues, preventing PU formation and promoting wound healing.Graphical

Advances in Escherichia coli-Based Therapeutic Protein Expression: Mammalian Conversion, Continuous Manufacturing, and Cell-Free Production

Therapeutic proteins treat many acute and chronic diseases that were until recently considered untreatable. However, their high development cost keeps them out of reach of most patients around the world. One plausible solution to lower-cost manufacturing is to adopt newer technologies like using Escherichia coli to express larger molecules, including full-length antibodies, generally relegated to Chinese Hamster Ovary (CHO) cells, adopt continuous manufacturing, and convert the manufacturing to cell-free synthesis. The advantages of using E. coli include a shorter production cycle, little risk of viral contamination, cell host stability, and a highly reproducible post-translational modification.

Domain Specificity of Anti-Prothrombin Antibodies That Express Lupus Anticoagulant Activity

Background: The antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the persistent presence of antiphospholipid antibodies (aPL). aPL are a heterogeneous group of autoantibodies directed against negatively charged phospholipids or phospholipid-binding proteins. Some of these autoantibodies exert lupus anticoagulant (LAC) activity, a laboratory phenomenon characterized by the prolongation of phospholipid-dependent coagulation tests. Recently, our group identified that LAC-positive anti-prothrombin antibodies activate platelets via the platelet receptor, FcγRIIA. However, a lot is still unclear regarding the mechanism by which these antibodies cause LAC and why some, but not all, antibodies in this heterogeneous group express LAC activity. Furthermore, experimental data on the binding site of these pathogenic anti-prothrombin antibodies are lacking. Aims: In this study we aimed to investigate the binding domain of LAC-positive monoclonal anti-prothrombin antibodies and APS patient derived anti-prothrombin antibodies. Method: Recombinant fragments of prothrombin were designed and produced in Chinese hamster ovary cells. Prothrombin fragment 1, fragment 2 and fragment 1.2 were coated on ELISA plates to study epitope specificity. Two LAC-positive monoclonal anti-prothrombin antibodies (3B1 and 28F4), two LAC-negative anti-prothrombin monoclonal antibodies (11H2 and 9C6), isolated anti-prothrombin antibodies derived from APS patients and plasma from APS patients were studied. A modified dilute Russell's viper venom time (DRVVT) test was used to evaluate whether the recombinant prothrombin constructs could neutralize the effect of LAC-positive monoclonal and patient derived anti-prothrombin antibodies. Furthermore, a fragment 1.2 nanobody was produced by immunizing Llama's followed by phage display. The ability of this nanobody to compete with LAC-positive monoclonal and patient derived anti-prothrombin antibodies for the prothrombin binding site was tested using a modified DRVVT test. Results: LAC-positive monoclonal anti-prothrombin antibodies recognized prothrombin fragment 2. Interestingly, LAC-negative anti-prothrombin antibodies bound exclusively to prothrombin fragment 1. In addition, LAC-ratios of patient samples correlated significantly with anti-fragment 2 antibody levels ( p<0.05, ρ=0.33), but not with anti-fragment 1 antibody levels. Furthermore, incubation with the prothrombin F1.2 nanobody almost completely reversed the prolonged DRVVT clotting time in plasma containing monoclonal and patient derived LAC-positive anti-prothrombin antibodies, but not in plasma containing LAC-positive anti-β2GP1 antibodies. This neutralising effect was also observed when the monoclonal anti-prothrombin antibody was incubated with prothrombin fragment 2. In contrast, the LAC-activity of anti-prothrombin antibodies was not inhibited when incubated with prothrombin fragment 1. Conclusion: Our data show that LAC-positive anti-prothrombin antibodies react with fragment 2 of prothrombin. Furthermore, a novel nanobody directed against prothrombin fragment 1.2 and prothrombin fragment 2 were able to neutralize a prothrombin-dependent LAC.

Eltrombopag Plus Rhtpo for Corticosteroid-Resistant or Relapsed ITP: A Prospective Observed Study

During the COVID-19 pandemic, the classical subsequent treatment regimen for immune thrombocytopenia (ITP) of immunosuppressants and/or steroids might increase patients' susceptibility of virus infections. To minimize ITP patients' risk during the COVID-19 global crisis and to improve treatment efficacy, non-immunosuppressive therapies, mainly including thrombopoietin mimetics, such as eltrombopag or recombinant human thrombopoietin (rhTPO), may be better for them. Eltrombopag, a small molecule agonist of thrombopoietin receptor (TPO-RA), was recommended as the subsequent treatment for ITP patients, which also already showed robust efficacy. However, inefficacy, loss of response and fluctuation of platelet counts during treatment were the serious problems in eltrombopag treatment for corticosteroid-resistant or relapsed ITP.RhTPO is a full-length glycosylated-TPO produced by Chinese hamster ovary cells, which showed its effectiveness in ITP in a variety of studies.For the difference of rh-TPO and eltrombopag , it had distinct molecular structures, treatment mechanisms, and pharmacokinetic characteristics and thus different response patterns and side effect profile. Previous studies have confirmed the safety and effectiveness of switching between rh-TPO and eltrombopag for ITP patients who had no response to or experienced adverse events with their first TPO-RA.However, no study has focused on the safe and effectiveness of the combination therapy of eltrombopag and rhTPO.The investigators hypothesized that the combination of these two agents could be a promising option for ITP treatment. Methods This is a prospective observed study to investigate the efficacy and safety of eltrombopag plus rhTPO as treatment for corticosteroid-resistant or relapsed ITP during the COVID-19 pandemic. Participation Criteria The inclusion criteria were as follows:Clinically confirmed corticosteroid-resistant or relapsed primary ITP;Platelet count less than 30×10^9/L on two occasions or platelets above 30×10^9/L combined with bleeding manifestation (WHO bleeding scale 2 or above);≥ 18 years. Exclusion Criteria: with secondary ITP such as drug-related thrombocytopenia, viral infection-induced thrombocytopenia, or a known diagnosis of another autoimmune disease; with other possible causes of thrombocytopenia, such as leukaemia, myelodysplastic syndrome, and aplastic anaemia; impaired renal function as indicated by a serum creatinine level > 2.0 mg/dL;inadequate liver function as indicated by a total bilirubin level > 2.0 mg/dL and/or an aspartate aminotransaminase or alanine aminotransferase level > 3×upper limit of normal; with a New York Heart Classification III or IV heart disease; with a history of severe psychiatric disorder or are unable to comply with study and follow-up procedures; pregnant or lactating women, or plan to become pregnant or impregnated within 12 months of receiving study drug; previous splenectomy; with previous or concomitant malignant disease; expected survival of < 2 years;not willing to participate in the study. Procedure For the patients with the combination therapy of eltrombopag and rhTPO, they received eltrombopag 25-75 mg oral daily and rh-TPO 300U/kg subcutaneous injection once daily for 7 consecutive days, followed by a tapering dose in maintenance therapy to maintain the platelet count between 50-150×10 9/L. Results From September 2nd, 2020, to July 1st, 2023, a total of 29 patients with corticosteroid-resistant or relapsed ITP were enrolled to receive eltrombopag plus rhTPO treatment, which included 11 male and 18 female patients.The median age were 55 (23-91) years old. The baseline platelete count was 7 (1-17)×10 9/L. Most patients (69.0%) were with severe ITP (platelet counts≤10×10 9/L or bleeding score ≥5).Response was defined as the achievement of platelet counts ≥30 × 10 9/L and ≥2 times the baseline platelet count at least once with treatment.The response rates at 1 week (early response) and 1 month ( initial response) were 37.9%(11/29) and 62.1%(18/29), respectively. After 6 weeks' treatment, 82.8% (25/29) of patients achieved response, and the improvement of bleeding symptoms were observed in most patients (89.7%).No thromboembolic events occurred during treatment. Conclusion Elrtombopag and rhTPO was a safe and effective therapy for corticosteroid-resistant or relapsed ITP, especially for severe ITP.