Biology subjects

Gutierrez, J. M.

Publications and source records attributed to Gutierrez, J. M..

3 recordsLinked to original sources

bioRxiv2018

Deficient skeletal muscle regeneration after injury induced by a Clostridium perfringens strain associated with gas gangrene

Very little is known about the muscle regeneration process that follows myonecrosis induced by C. perfringens, the main agent of gas gangrene. This study revealed that, in a murine model of the infection with a sublethal inoculum of C. perfringens, muscle necrosis occurs concomitantly with significant vascular damage, which limits the migration of inflammatory cells. A significant increase in cytokines that promote inflammation explains the presence of inflammatory infiltrate; however, an impaired IFN{gamma} expression, a reduced number of Ml macrophages, a deficient phagocytic activity, and the prolongation of the permanence of inflammatory cells, lead to deficient muscle regeneration. The expression of TGF{beta}1 and the consequent accumulation of collagen in the muscle, likely contribute to the fibrosis observed 30 days after infection. These results provide new information on the pathogenesis of gas gangrene caused by C. perfringens, shed light on the basis of the poor muscle regenerative activity, and may open new perspectives for the development of novel therapies for patients suffering this disease.

microbiology↗

bioRxiv2018

Combating viral contaminants in CHO cells by engineering STAT1 mediated innate immunity

Viral contamination in biopharmaceutical manufacturing can lead to shortages in the supply of critical therapeutics. To facilitate the protection of bioprocesses, we explored the basis for the susceptibility of CHO cells, the most commonly used cell line in biomanufacturing, to RNA virus infection. Upon infection with certain ssRNA and dsRNA viruses, CHO cells fail to generate a significant interferon (IFN) response. Nonetheless, the downstream machinery for generating IFN responses and its antiviral activity is intact in these cells: treatment of cells with exogenously-added type I IFN or poly I:C prior to infection limited the cytopathic effect from Vesicular stomatitis virus (VSV), Encephalomyocarditis virus (EMCV), and Reovirus-3 virus (Reo-3) in a STAT1-dependent manner. To harness the intrinsic antiviral mechanism, we used RNA-Seq to identify two upstream repressors of STAT1: Gfi1 and Trim24. By knocking out these genes, the engineered CHO cells exhibited increased resistance to the prototype RNA viruses tested. Thus, omics-guided engineering of mammalian cell culture can be deployed to increase safety in biotherapeutic protein production among many other biomedical applications.

bioengineering↗

bioRxiv2018

Genome-scale reconstructions of the mammalian secretory pathway predict metabolic costs and limitations of protein secretion

In mammalian cells, >25% of synthesized proteins are exported through the secretory pathway. The pathway complexity, however, obfuscates its impact on the secretion of different proteins. Unraveling its impact on diverse proteins is particularly important for biopharmaceutical production. Here we delineate the core secretory pathway functions and integrate them with genome-scale metabolic reconstructions of human, mouse, and Chinese hamster cells. The resulting reconstructions enable the computation of energetic costs and machinery demands of each secreted protein. By integrating additional omics data, we find that highly secretory cells have adapted to reduce expression and secretion of other expensive host cell proteins. Furthermore, we predict metabolic costs and maximum productivities of biotherapeutic proteins and identify protein features that most significantly impact protein secretion. Finally, the model successfully predicts the increase in secretion of a monoclonal antibody after silencing a highly expressed selection marker. This work represents a knowledgebase of the mammalian secretory pathway that serves as a novel tool for systems biotechnology.

systems biology↗