Chronic Psychological Stress, but Not Chronic Pain Stress, Influences Sexual Motivation and Induces Testicular Autophagy in Male Rats.

Spermiogenesis is an important physiological process of mammalian fertilization. The germ cells are susceptible to the harmful effects of either psychological or physiological stress, which could induce male infertility. Our previous studies have found that chronic psychological stress could decrease sexual motivation. However, molecular mechanisms underlying male reproductive toxicity induced by chronic stress remain elusive. Recently, autophagy is proven to be involved in regulating the survival of germ cells, which is related to apoptosis. Herein, we established a chronic psychological stress model and a chronic pain model (physiological stressor) to explore the roles of autophagy in germ cells. Thirty-two male Sprague-Dawley rats were randomly divided into four groups, including the control group, the chronic psychological stress group, the SNI-sham group, and the chronic pain stress group. After exposure to stress for 35 days, open field test and the unconditioned sexual motivation test were performed. Following the behavioral experiment, autophagy in the rat testis was detected by Western blot and immunohistochemistry. We found both chronic psychological stress and chronic pain stress reduced total travel distance, the frequency of central crossing and increased the sensitivity to mechanical pain. While chronic psychological stress, but not the chronic pain stress declined sexual motivation. Chronic psychological stress prompt the expression of LC3-II with the decreased expression of p62, indicating that chronic psychological stress induced autophagy in rat testis. However, there was no significant difference between the expression of LC3-II and p62 in male rats under chronic pain stress. Therefore, chronic psychological stress and chronic pain stress have common behavior changes, but due to its unpredictability, chronic psychological stress leads to a decline in sexual motivation in male rats and induced the autophagy in testicular tissues.

Biopharmaceutical Industry Practices for Sequence Variant Analyses of Recombinant Protein Therapeutics.

The application of advanced methodologies such as next-generation sequencing (NGS) and mass spectrometry (MS) to the characterization of cell lines and recombinant proteins has enabled the highly sensitive detection of sequence variants (SVs). However, although these approaches can be leveraged to provide deep insight into product microheterogeneity caused by SVs, they are not used in a standardized manner across the industry. Currently, there is little clarity and consensus on the utilization, timing, and significance of SV findings. This white paper addresses the current practices, logistics, and strategies for the analysis of SVs using a benchmarking survey coordinated by the International Consortium for Innovation & Quality in Pharmaceutical Development (IQ) as well as a series of deliberations among a panel of experts assembled from across the biopharmaceutical industry. Discussion includes current industry experiences including approaches for detection and quantitation of SVs during cell-line and process development, risk assessments, and regulatory feedback. Although SVs are a potential issue for all recombinant protein therapeutics, the scope of this discussion will be limited to SVs produced in mammalian cells. Ultimately, it is our hope that the findings from the survey and deliberations of the committee are useful to decision makers in industry and positions them to respond to findings of SVs in recombinant proteins that are destined for clinical or commercial use in a strategic manner.LAY ABSTRACT: This white paper addresses the current practices, logistics, and strategies for the analysis of amino acid sequence variants using a benchmarking survey coordinated by the International Consortium for Innovation & Quality in Pharmaceutical Development (IQ) as well as a series of deliberations among a panel of experts assembled from across the biopharmaceutical industry. Discussion includes current industry experiences regarding detection and quantitation of SVs during cell-line and process development, risk assessments, and regulatory feedback.

Elucidating the Impact of CHO Cell Culture Media on Tryptophan Oxidation of a Monoclonal Antibody Through Gene Expression Analyses.

Oxidation of monoclonal antibodies (mAb) is a common chemical modification with potential impact on a therapeutic protein's activity and immunogenicity. In a previous study, it was found that tryptophan oxidation (Trp-ox) levels of two mAb produced in Chinese hamster ovary (CHO) cells were significantly lowered by modifying cell culture medium/feed. In this study, transcriptome analysis by RNA-Seq is applied to further elucidate the underlying mechanism of those changes in lowering the Trp-ox levels. Cell samples from the 5L fed-batch conditions are harvested and subjected to RNA-Seq analysis. The results showed that the cell culture changes had little impact on neither the expression of the mAb transgenes nor genes related to glycosylation. However, those changes did significantly alter the expression of multiple genes (p-value ≤0.05 and absolute fold change ≥1.5 or adjusted p-value ≤0.1) involved in transport of copper, regulation of glutathione, iron storage, heme reduction, oxidative phosphorylation, and Nrf2-mediated antioxidative response. These findings suggest a key underlying mechanism in lowering Trp-ox levels by CDM was likely to be collectively controlling ROS levels through regulation of those genes' expression. This is the first example, to our knowledge, applying transcriptomic analysis to mechanistically understand the impact of cell culture on mAb oxidation.

Transgene copy number distribution profiles in recombinant CHO cell lines revealed by single cell analyses.

Clonally derived recombinant cell lines are highly desired to achieve consistent production of recombinant biotherapeutics. Despite repeated rounds of cloning by limiting dilution or single cell cloning, the resulting cell lines have often been observed to diverge, becoming a heterogeneous population and losing productivity over long-term sub-culturing. To understand the underlying molecular mechanisms, we developed quantitative polymerase chain reaction (qPCR) assays for the analysis of transgene copy number distribution in single recombinant cells isolated from Chinese hamster ovary (CHO) cell lines. Single cells were obtained by fluorescence activated cell sorting (FACS) technology and lysed directly in 96-well plates. qPCR assays were then applied to analyze the quantity and distribution of transgenes in those single cells. Results revealed multiple types of transgene copy number distribution profiles from those clonally derived CHO cell lines. The cell lines that maintained productivity over time displayed relatively constant and homogeneous transgene copy number distributions; while most of those cell lines exhibiting a loss of productivity over time showed varying degrees of transgene copy number heterogeneity and distribution drift with passaging. Some cell lines showed the existence of a significant portion of cells lacking the transgenes (referred to as negative cells in this study) and the percentage of those negative cells increased with subsequent generations. Criteria based on transgene copy number distribution profiles were developed to assess cell line suitability for clinical applications, which include (i) percentage of negative cells; (ii) standard deviation of qPCR threshold cycle (C(t) ) value, a measure of population heterogeneity; (iii) mean C(t) changes during aging, a measure of population drift. By implementing these criteria, undesirable cell lines were eliminated for further clinical and commercial applications.

Lethality of glnD null mutations in Azotobacter vinelandii is suppressible by prevention of glutamine synthetase adenylylation.

GlnD is a pivotal protein in sensing intracellular levels of fixed nitrogen and has been best studied in enteric bacteria, where it reversibly uridylylates two related proteins, PII and GlnK. The uridylylation state of these proteins determines the activities of glutamine synthetase (GS) and NtrC. Results presented here demonstrate that glnD is an essential gene in Azotobacter vinelandii. Null glnD mutations were introduced into the A. vinelandii genome, but none could be stably maintained unless a second mutation was present that resulted in unregulated activity of GS. One mutation, gln-71, occurred spontaneously to give strain MV71, which failed to uridylylate the GlnK protein. The second, created by design, was glnAY407F (MV75), altering the adenylylation site of GS. The gln-71 mutation is probably located in glnE, encoding adenylyltransferase, because introducing the Escherichia coli glnE gene into MV72, a glnD(+) derivative of MV71, restored the regulation of GS activity. GlnK-UMP is therefore apparently required for GS to be sufficiently deadenylylated in A. vinelandii for growth to occur. The DeltaglnD GS(c) isolates were Nif(-), which could be corrected by introducing a nifL mutation, confirming a role for GlnD in mediating nif gene regulation via some aspect of the NifL/NifA interaction. MV71 was unexpectedly NtrC(+), suggesting that A. vinelandii NtrC activity might be regulated differently than in enteric organisms.