Metabolic engineering of mammalian cells to produce heparan sulfates

2018 ◽  
Vol 2 (3) ◽  
pp. 443-452 ◽  
Author(s):  
Bryan E. Thacker ◽  
Susan T. Sharfstein

Heparan sulfate (HS) is a glycosaminoglycan produced by all mammalian cells that plays important roles in physiology and various pathologies. Heparin is a highly sulfated form of HS that is used clinically as an anticoagulant. Heparin and HSs may also have therapeutic benefits for a wide variety of other indications. Cultured mammalian cells produce HS and, through genetic modification, have been used to elucidate the biosynthetic pathway. Recently, metabolic engineering has been used to produce HS from cultured mammalian cells for clinical purposes. This review describes the HS biosynthetic pathway and its manipulation through metabolic engineering to produce bioengineered HSs. We also discuss current challenges and opportunities to advance the field of HS metabolic engineering.

2021 ◽  
Author(s):  
Bridget M Hulsebosch ◽  
Oreoluwa S Omoba ◽  
Natalie J LoMascolo ◽  
Bryan C. Mounce

Productive viral infection begins with attachment to a susceptible cell, and viruses have evolved complex mechanisms to attach to and subsequently enter cells. Prior to engagement with a cellular receptor, viruses frequently interact with nonspecific attachment factors that can facilitate virus-receptor interactions and viral entry. Polyamines, small positively-charged molecules abundant in mammalian cells, mediate viral attachment, though the mechanism was not fully understood. Using the Coxsackievirus B3 (CVB3) enterovirus model system, we show that polyamines mediate viral attachment both directly and indirectly. The polyamine putrescine specifically enhances viral attachment to cells depleted of polyamines. Putrescine's positive charge mediates its ability to enhance viral attachment, and polyamine analogs are less efficient at mediating viral attachment. In addition to this direct role of polyamines in attachment, polyamines facilitate the cellular expression of heparan sulfates, negatively-charged molecules found on the cell surface. In polyamine-depleted cells, heparan sulfates are depleted from the surface of cells, resulting in reduced viral attachment. We find that this is due to polyamines' role in the process of hypusination of eukaryotic initiation factor 5A, which facilitates cellular translation. These data highlight the important role of polyamines in mediating cellular attachment, as well as their function in facilitating cellular heparan sulfate synthesis.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Zhenyu Zhang ◽  
Pengfu Liu ◽  
Weike Su ◽  
Huawei Zhang ◽  
Wenqian Xu ◽  
...  

AbstractTrans-4-hydroxy-l-proline is an important amino acid that is widely used in medicinal and industrial applications, particularly as a valuable chiral building block for the organic synthesis of pharmaceuticals. Traditionally, trans-4-hydroxy-l-proline is produced by the acidic hydrolysis of collagen, but this process has serious drawbacks, such as low productivity, a complex process and heavy environmental pollution. Presently, trans-4-hydroxy-l-proline is mainly produced via fermentative production by microorganisms. Some recently published advances in metabolic engineering have been used to effectively construct microbial cell factories that have improved the trans-4-hydroxy-l-proline biosynthetic pathway. To probe the potential of microorganisms for trans-4-hydroxy-l-proline production, new strategies and tools must be proposed. In this review, we provide a comprehensive understanding of trans-4-hydroxy-l-proline, including its biosynthetic pathway, proline hydroxylases and production by metabolic engineering, with a focus on improving its production.


2010 ◽  
Vol 192 (7) ◽  
pp. 1999-2005 ◽  
Author(s):  
Amalia Porta ◽  
Annamaria Eletto ◽  
Zsolt Török ◽  
Silvia Franceschelli ◽  
Attila Glatz ◽  
...  

ABSTRACT So far attenuation of pathogens has been mainly obtained by chemical or heat treatment of microbial pathogens. Recently, live attenuated strains have been produced by genetic modification. We have previously demonstrated that in several prokaryotes as well as in yeasts and mammalian cells the heat shock response is controlled by the membrane physical state (MPS). We have also shown that in Salmonella enterica serovar Typhimurium LT2 (Salmonella Typhimurium) overexpression of a Δ12-desaturase gene alters the MPS, inducing a sharp impairment of transcription of major heat shock genes and failure of the pathogen to grow inside macrophage (MΦ) (A. Porta et al., J. Bacteriol. 192:1988-1998, 2010). Here, we show that overexpression of a homologous Δ9-desaturase sequence in the highly virulent G217B strain of the human fungal pathogen Histoplasma capsulatum causes loss of its ability to survive and persist within murine MΦ along with the impairment of the heat shock response. When the attenuated strain of H. capsulatum was injected in a mouse model of infection, it did not cause disease. Further, treated mice were protected when challenged with the virulent fungal parental strain. Attenuation of virulence in MΦ of two evolutionarily distant pathogens was obtained by genetic modification of the MPS, suggesting that this is a new method that may be used to produce attenuation or loss of virulence in both other intracellular prokaryotic and eukaryotic pathogens. This new procedure to generate attenuated forms of pathogens may be used eventually to produce a novel class of vaccines based on the genetic manipulation of a pathogen's membrane fluid state and stress response.


2019 ◽  
Vol 20 (19) ◽  
pp. 4764 ◽  
Author(s):  
Marzia Ognibene ◽  
Marina Podestà ◽  
Alberto Garaventa ◽  
Annalisa Pezzolo

Neuroblastoma (NB) is an aggressive, relapse-prone infancy tumor of the sympathetic nervous system and is the leading cause of death among preschool age diseases, so the search for novel therapeutic targets is crucial. Golgi phosphoprotein 3 (GOLPH3) has been reported to be involved in the development, and in the DNA damage response, of various human cancers. Golgi dispersal is a common feature of DNA damage response in mammalian cells. Understanding how cells react to DNA damage is essential in order to recognize the systems used to escape from elimination. We induced DNA damage in two human neuroblastoma cell lines by curcumin. The exposure of neuroblastoma cells to curcumin induced: (a) up-regulation of GOLPH3+ cells; (b) augmentation of double-strand breaks; (c) Golgi fragmentation and dispersal throughout the cytoplasm; (d) increase of apoptosis and autophagy; (e) increased expression of TPX2 oncoprotein, able to repair DNA damage. Primary neuroblastoma samples analysis confirmed these observations. Our findings suggest that GOLPH3 expression levels may represent a clinical marker of neuroblastoma patients’ responsiveness to DNA damaging therapies—and of possible resistance to them. Novel molecules able to interfere with GOLPH3 and TPX2 pathways may have therapeutic benefits when used in combination with standard DNA damaging therapeutic agents in neuroblastoma


Author(s):  
Ritesh Tandon ◽  
Joshua S. Sharp ◽  
Fuming Zhang ◽  
Vitor H. Pomin ◽  
Nicole M. Ashpole ◽  
...  

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has caused a pandemic of historic proportions and continues to spread globally, with enormous consequences to human health. Currently there is no vaccine, effective therapeutic or prophylactic. Like other betacoronaviruses, attachment and entry of SARS-CoV-2 is mediated by the spike glycoprotein (SGP). In addition to its well-documented interaction with its receptor, human angiotensin converting enzyme 2 (hACE2), SGP has been found to bind to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we pseudotyped SARS-CoV-2 SGP on a third generation lentiviral (pLV) vector and tested the impact of various sulfated polysaccharides on transduction efficiency in mammalian cells. The pLV vector pseudotyped SGP efficiently and produced high titers on HEK293T cells. Various sulfated polysaccharides potently neutralized pLV-S pseudotyped virus with clear structure-based differences in anti-viral activity and affinity to SGP. Concentration-response curves showed that pLV-S particles were efficiently neutralized by a range of concentrations of unfractionated heparin (UFH), enoxaparin, 6-O-desulfated UFH and 6-O-desulfated enoxaparin with an IC50 of 5.99 μg/L, 1.08 mg/L, 1.77 μg/L, and 5.86 mg/L respectively. In summary, several sulfated polysaccharides show potent anti-SARS-CoV-2 activity and can be developed for prophylactic as well as therapeutic purposes. Importance The recent emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) in Wuhan, China in late 2019 and its subsequent spread to the rest of the world has created a pandemic situation unprecedented in modern history. While ACE2 has been identified as the viral receptor, cellular polysaccharides have also been implicated in virus entry. The SARS-CoV-2 spike glycoprotein (SGP) binds to glycosaminoglycans like heparan sulfate, which is found on the surface of virtually all mammalian cells. Here, we report structure-based differences in anti-viral activity and affinity to SGP for several sulfated polysaccharides, including both well-characterized FDA-approved drugs and novel marine sulfated polysaccharides, which can be developed for prophylactic as well as therapeutic purposes.


1990 ◽  
Vol 111 (4) ◽  
pp. 1651-1659 ◽  
Author(s):  
R Flaumenhaft ◽  
D Moscatelli ◽  
D B Rifkin

The radius of diffusion of basic FGF (bFGF) in the presence and in the absence of the glycosaminoglycans heparin and heparan sulfate was measured. Iodinated 125I-bFGF diffuses further in agarose, fibrin, and on a monolayer of bovine aortic endothelial (BAE) cells in the presence of heparin than in its absence. Heparan sulfates affected the diffusion of 125I-bFGF in a manner similar to, though less pronounced than, heparin. When applied at the center of a monolayer of BAE cells, bFGF plus heparin stimulated morphological changes at a 10-fold greater radius than bFGF alone. These results suggest that bFGF-heparin and/or heparan sulfate complexes may be more effective than bFGF alone in stimulating cells located away from the bFGF source because the bFGF-glycosaminoglycan complex partitions into the soluble phase rather than binding to insoluble glycosaminoglycans in the extracellular matrix. Thus, the complex of bFGF and glycosaminoglycan may represent one of the active forms of bFGF in vivo.


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