HEK293 Cells Overexpressing Nuclear Factor E2-Related Factor-2 Improve Expression of Recombinant Coagulation Factor VII

Efficient production of recombinant human FVII in CHO cells using the piggyBac transposon system

As an important coagulation factor, activated coagulation factor VII (FVIIa) is mainly used to treat the bleeding of hemophilia patients who have developed inhibitory antibodies against FVIII and FIX conventional treatment. Recombinant human factor VII (rhFVII) produced in mammalian cell lines have been developed as the most important resource of FVIIa. However, cell lines express rhFVII protein derived from an exogenous expression vector at a lower level than most other proteins. In the current study, we have shown efficient rhFVII production in CHO cell lines using piggyBac (PB) transposon system. rhFVII is successfully expressed in fed-batch culture of CHO cells, and the expression of rhFVII up to 100 mg/L. Moreover, the purified secreted rhFVII was determined by SDS-PAGE and Western Blot. The coagulation activity was determined by the chromogenic Activity ELISA kit. In conclusion, this study has demonstrated that the piggyBac transposon system can be used for an efficient production of recombinant FVII.

Knockout of Pro-Apoptotic BAX and BAK1 Genes in HEK293T Cells Enhances Adeno-Associated Virus (AAV) Production: AAV2 and AAV9

Increasing demand for adeno-associated virus (AAV) used in gene therapy highlights the need to enhance AAV production. When intracellular AAV2 and extracellular AAV9 were produced in HEK293T cells using the triple transfection method, apoptosis occurred during the AAV production. To mitigate apoptosis induced by AAV production, the pro-apoptotic BAX/BAK1 genes were knocked out in HEK293T cells. BAX/BAK1 knockout (BBKO) in HEK293T cells significantly increased the production of both AAV2 and AAV9. For AAV2, BBKO increased the genome titer of AAV2 by 55% without negatively affecting the proportion of unwanted empty capsids generated during AAV production. Empty capsid ratios were determined based on viral genome and capsid titers and confirmed via transmission electron microscopy (TEM). Likewise, for AAV9, BBKO increased the genome titer of AAV9 by 66% without negatively affecting the proportion of empty capsids. Additionally, as assessed using a transduction assay, BBKO increased the functional titers of AAV2 and AAV9 by 30% and 46%, respectively. Therefore, BBKO increased AAV production, while maintaining full capsid ratio and infectivity. Taken together, BBKO proved to be an efficient method for enhancing AAV production in HEK293T cells for both AAV2 and AAV9.

Interferon alpha and beta receptor 1 knockout in human embryonic kidney 293 cells enhances the production efficiency of proteins or adenoviral vectors related to type I interferons

Human embryonic kidney (HEK) 293 cells are widely used in protein and viral vector production owing to their high transfection efficiency, rapid growth, and suspension growth capability. Given their antiviral, anticancer, and immune-enhancing effects, type I interferons (IFNs) have been used to prevent and treat human and animal diseases. However, the binding of type I IFNs to the IFN-α and-β receptor (IFNAR) stimulates the expression of IFN-stimulated genes (ISGs). This phenomenon induces an antiviral state and promotes apoptosis in cells, thereby impeding protein or viral vector production. In this study, we generated an IFNAR subtype 1 knockout (KO) HEK 293 suspension (IFNAR-KO) cell line by using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) technology. Upon treatment with human IFN-α, the IFNAR-KO cells showed a constant expression of ISGs, including 2'-5'-oligoadenylate synthetase 1 (OAS1), myxovirus resistance 1 (Mx1), protein kinase RNA-activated (PKR), and IFN-induced transmembrane protein 1 (IFITM1), when compared with the wild-type HEK 293 (WT) cells, wherein the ISGs were significantly upregulated. As a result, the titer of recombinant adenovirus expressing porcine IFN-α was significantly higher in the IFNAR-KO cells than in the WT cells. Furthermore, the IFNAR-KO cells continuously produced higher amounts of IFN-α protein than the WT cells. Thus, the CRISPR-Cas9-mediated IFNAR1 KO cell line can improve the production efficiency of proteins or viral vectors related to IFNs. The novel cell line may be used for producing vaccines and elucidating the type I IFN signaling pathway in cells.

SA/G hydrogel containing NRF2-engineered HEK-293-derived CM improves wound healing efficacy of WJ-MSCs in a rat model of excision injury

AIM OF THE STUDY

Skin wounds are a major public health issue due to the lack of real effective remedies. Mesenchymal stem cells (MSCs) are considered as a promising therapeutic strategy for wound injuries; however, low survival rate following transplantation limited their application. In an attempt to introduce a novel potential wound dressing and improve wound healing properties, the current study was conducted.

MATERIAL AND METHODS

we prepared conditioned medium (CM) harvested from HEK-293 cells overexpressing nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of antioxidant genes expression. Then, the CM was loaded in a biodegradable hydrogel. Next, in an animal model of full-thickness excision wound, wharton's jelly derived-mesenchymal stem cells (WJ-MSCs) were transplanted at the margins of the wound followed by application of the hydrogel on injury site. Finally, wound healing characteristics were evaluated by proper methods.

RESULTS

Our findings revealed that, the NRF2-CM protected the WJ-MSCs against H₂O₂-induced toxicity in vitro. Furthermore, in vivo results showed that, SA/G hydrogel containing NRF2-CM significantly (P < 0.01) promoted WJ-MSCs survival, increased angiogenesis, accelerated wound contraction, and promoted wound healing compared to other groups.

CONCLUSION

Though further preclinical and clinical studies regarding mechanisms behind the protection and also safety of the strategy are needed, our findings strongly suggest that the prepared wound dressing enhanced the efficacy of therapeutic potential of WJ-MSCs by providing an enriched/antioxidant niche support.

Affecting HEK293 Cell Growth and Production Performance by Modifying the Expression of Specific Genes

The HEK293 cell line has earned its place as a producer of biotherapeutics. In addition to its ease of growth in serum-free suspension culture and its amenability to transfection, this cell line’s most important attribute is its human origin, which makes it suitable to produce biologics intended for human use. At the present time, the growth and production properties of the HEK293 cell line are inferior to those of non-human cell lines, such as the Chinese hamster ovary (CHO) and the murine myeloma NSO cell lines. However, the modification of genes involved in cellular processes, such as cell proliferation, apoptosis, metabolism, glycosylation, secretion, and protein folding, in addition to bioprocess, media, and vector optimization, have greatly improved the performance of this cell line. This review provides a comprehensive summary of important achievements in HEK293 cell line engineering and on the global engineering approaches and functional genomic tools that have been employed to identify relevant genes for targeted engineering.