Enhanced metabolism and negative regulation of ER stress support higher erythropoietin production in HEK293 cells

Recombinant protein production can cause severe stress on cellular metabolism, resulting in limited titer and product quality. To investigate cellular and metabolic characteristics associated with these limitations, we compare HEK293 clones producing either erythropoietin (EPO) (secretory) or GFP (non-secretory) protein at different rates. Transcriptomic and functional analyses indicate significantly higher metabolism and oxidative phosphorylation in EPO producers compared with parental and GFP cells. In addition, ribosomal genes exhibit specific expression patterns depending on the recombinant protein and the production rate. In a clone displaying a dramatically increased EPO secretion, we detect higher gene expression related to negative regulation of endoplasmic reticulum (ER) stress, including upregulation of ATF6B, which aids EPO production in a subset of clones by overexpression or small interfering RNA (siRNA) knockdown. Our results offer potential target pathways and genes for further development of the secretory power in mammalian cell factories.

Polymorphism in the 3'-UTR of LIF but Not in the ATF6B Gene Associates with Schizophrenia Susceptibility: a Case-Control Study and In Silico Analyses

Schizophrenia (SCZ) is a multifactorial disorder caused by environmental and genetic factors. Studies have shown that various single-nucleotide polymorphisms (SNPs) in the binding sites of microRNAs contribute to the risk of developing SCZ. We aimed to investigate whether the variants located in the 3'-UTR region of LIF (rs929271T>G) and ATF6B (rs8283G>A) were associated with increased susceptibility to SCZ in a population from the south-east of Iran. In this case-control study, a total of 396 subjects were recruited. SNPs were genotyped via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Genotyping results showed that the G allele of rs929271 significantly increased the risk of SCZ (OR = 1.58 95%CI = 1.19-2.10, p = 0.001). As for rs929271, the GG genotype of co-dominant (OR = 2.54 95%CI = 1.39-4.64, p = 0.002) and recessive (OR = 2.91 95%CI = 1.77-4.80, p < 0.001) models were strongly linked to SCZ. No significant differences were observed between rs8283 polymorphism and predisposition to SCZ. In silico analyses predicted that rs929271 might alter the binding sites of microRNAs, which was believed to have an unclear role in the development of SCZ. Moreover, rs929271 polymorphism changed the LIF-mRNA folding structure. These findings provide fine pieces of evidence regarding the possible effects of LIF polymorphism in the development of SCZ and regulation of the LIF gene targeted by microRNAs.

Polymorphisms of ATF6B Are Potentially Associated With FEV1 Decline by Aspirin Provocation in Asthmatics

Purpose

Endoplasmic reticulum (ER) stress has recently been observed to activate NF-kappaB and induce inflammatory responses such as asthma. Activating transcription factor 6β (ATF6B) is known to regulate ATFα-mediated ER stress response. The aim of this study is to investigate the associations of ATF6B genetic variants with aspirin-exacerbated respiratory disease (AERD) and its major phenotype, % decline of FEV1 by aspirin provocation.

Methods

Four common single nucleotide polymorphisms (SNPs) of ATF6B were genotyped and statistically analyzed in 93 AERD patients and 96 aspirin-tolerant asthma (ATA) as controls.

Results

Logistic analysis revealed that 2 SNPs (rs2228628 and rs8111, P=0.008; corrected P=0.03) and 1 haplotype (ATF6B-ht4, P=0.005; corrected P=0.02) were significantly associated with % decline of FEV1 by aspirin provocation, whereas ATF6B polymorphisms and haplotypes were not associated with the risk of AERD.

Conclusions

Although further functional and replication studies are needed, our preliminary findings suggest that ATF6B may be related to obstructive phenotypes in response to aspirin exposure in adult asthmatics.