Bordetella pertussis is the bacterial causative agent of whooping cough, a serious respiratory illness. An extensive knowledge on its virulence regulation and metabolism is a key factor to ensure pertussis vaccine manufacturing process robustness. The aim of this study was to refine our comprehension of B. pertussis physiology during in vitro cultures in bioreactors. A longitudinal multi-omics analysis was carried out over 26 h small-scale cultures of B. pertussis. Cultures were performed in batch mode and under culture conditions intending to mimic industrial processes. Putative cysteine and proline starvations were, respectively, observed at the beginning of the exponential phase (from 4 to 8 h) and during the exponential phase (18 h 45 min). As revealed by multi-omics analyses, the proline starvation induced major molecular changes, including a transient metabolism with internal stock consumption. In the meantime, growth and specific total PT, PRN, and Fim2 antigen productions were negatively affected. Interestingly, the master virulence-regulating two-component system of B. pertussis (BvgASR) was not evidenced as the sole virulence regulator in this in vitro growth condition. Indeed, novel intermediate regulators were identified as putatively involved in the expression of some virulence-activated genes (vags). Such longitudinal multi-omics analysis applied to B. pertussis culture process emerges as a powerful tool for characterization and incremental optimization of vaccine antigen production.

Background: Inpatients with relaspsed/refractoryMultiple Myeloma (MM), outcomes are far from optimal, especially in patients refractory to current treatments Recent studies and clinical trials have highlighted the therapeutic potential of Palbociclib, a CDK4/6 inhibitor, in various cancers including MM. Deregulation of CDK4/6 is involved in the loss of cell cycle control in MM. Response to Palbociclib combined with bortezomib and dexamethasone was acquired in 20% of the relapsed/refractory MM patients, suggesting that biomarkers to identify patients that could benefit from this treatment are needed. Additional studies are required to understand the biological pathways associated with sensitivity or resistance of MM cells to Palbociclib. Methods: 14 human MM cell lines and 12 primary MM samples were tested for response to Palbociclib treatment. The concentration required to inhibit growth by 50% (IC50) was calculated. Gene expression signature associated with multiple myeloma response to Palbociclib, as well as, genes deregulated by the treatment have been analyzed using microarray and RNA-sequencing methods. Results: Palbociclib had an heterogeneous in vitro activity among the 14 human myeloma cell lines tested, which aggregated into three groups based on the distribution of the IC50 values: sensitive (n = 5, IC50: 0.2 - 0.3µM), intermediate (n = 3, IC50: 0.5 - 0.7µM) or more resistant group (n = 6, IC50: 0.9 - 2.4µM). The same holds true when testing the Palbociclib on primary multiple myeloma samples. The evaluation of the Palbociclib effect on cell cycle progression and the induction of the apoptosis, reveals that Palbociclib is essentially cytostatic, inducing prolonged G1 arrest in sensitive cell lines with a strong reduction of the percentage of cells in S phase. To better understand the molecular mechanisms associated with Palbociclib response, we identified a gene expression signature correlated with the response in both MM cell lines and primary myeloma cells from patients. Additionally, we have analyzed differentially expressed genes after Palbociclib treatment in human MM cell lines using RNA sequencing (n = 4). The physiological role of the downregulated genes after Palbociclib treatment is associated with cell cycle, mitosis and E2F mediated regulation of DNA replication. Significantly upregulated genes, after Palbociclib treatment, were enriched in genes encoding proteins involved in glutathione synthesis and recycling, and biological oxidations. Conclusion: Altogether, our data demonstrated a high heterogeneity in the response of MM cells to Palbociclib. We identified a gene expression signature associated with Palbociclib response in MM. These genes could help to identify MM patients that could benefit from Palbociclib treatment and provide novel targets for efficient combination therapy. Disclosures No relevant conflicts of interest to declare.