Validation of Recombinant Heparan Sulphate Reagents for CNS Repair

SIMPLE SUMMARY: The complex tissue changes that occur after central nervous system (CNS) damage/injury require a multi-target treatment approach. Specialised sugar molecules that reside in and around our cells, known as heparan sulphate (HS), regulate numerous cellular functions and are important for tissue repair. HS contains a chemical group called sulphate which, depending on the number and position, can make cells regulate different functions. To harness the potential of HS, we can mimic its function using heparin mimetics (mHeps). mHeps are modified from the blood-thinning drug heparin whose structure resembles HS. mHeps can be chemically altered to contain less or more sulphate. We have shown that mHeps with low levels of sulphate (low-sulphated) are beneficial for CNS repair. However, mHeps are manufactured from heparin obtained from pig intestines, the supply of which can risk contamination or suffer shortages. There are also ethical implications of using animal-derived products as future therapies. Next-generation HS mimics now exist which are derived from cultured cells, termed recombinant HS mimetics (rHS). rHS may also promote repair and would translate to the clinic more readily than pig tissue-derived compounds. We have therefore validated the repair potential of these newer next-generation mimetics and compared them with our lead low-sulphated compound. ABSTRACT: Therapies that target the multicellular pathology of central nervous system (CNS) disease/injury are urgently required. Modified non-anticoagulant heparins mimic the heparan sulphate (HS) glycan family and have been proposed as therapeutics for CNS repair since they are effective regulators of numerous cellular processes. Our in vitro studies have demonstrated that low-sulphated modified heparan sulphate mimetics (LS-mHeps) drive CNS repair. However, LS-mHeps are derived from pharmaceutical heparin purified from pig intestines, in a supply chain at risk of shortages and contamination. Alternatively, cellular synthesis of heparin and HS can be achieved using mammalian cell multiplex genome engineering, providing an alternative source of recombinant HS mimetics (rHS). TEGA Therapeutics (San Diego) have manufactured rHS reagents with varying degrees of sulphation and we have validated their ability to promote repair in vitro using models that mimic CNS injury, making comparisons to LS-mHep7, a previous lead compound. We have shown that like LS-mHep7, low-sulphated rHS compounds promote remyelination and reduce features of astrocytosis, and in contrast, highly sulphated rHS drive neurite outgrowth. Cellular production of heparin mimetics may, therefore, offer potential clinical benefits for CNS repair.