Overexpression of BDNF and uPA Combined with the Suppression of Von Hippel-Lindau Tumor Suppressor Enhances the Neuroprotective Activity of the Secretome of Human Mesenchymal Stromal Cells in the Model of Intracerebral Hemorrhage.

Nerve tissue damage is an unsolved problem in modern neurology and neurosurgery, which prompts the need to search for approaches to stimulate neuroprotection and regeneration of neural tissue. Earlier we have shown that the secretome of human mesenchymal stromal cells (MSCs) stimulates rat survival, reduces the severity of neurological deficits, and decreases the volume of brain damage in a hemorrhagic stroke model. A significant disadvantage of using the MSC secretome is the need to concentrate it (at least 5-10 fold) to achieve appreciable pharmacological activity. This increases the cost of obtaining clinically applicable amounts of secretome and slows down the clinical translation of this technology. Here, we created a number of genetically modified human MSC cultures, including immortalized MSCs and those with hyperexpression of brain-derived neurotrophic factor (BDNF) and urokinase-type plasminogen activator (uPA) and with suppressed expression of Von Hippel-Lindau tumor suppressor (VHL), and we evaluated the pharmacological activity of their secretomes in a model of intracerebral hemorrhage (ICH) in rats. The secretome of MSCs immortalized by hyperexpression of the catalytic subunit of human telomerase (hTERT) revealed neuroprotective activity indistinguishable from that of primary MSC cultures, yet it still required 10-fold concentration to achieve neuroprotective efficacy. The secretome of MSC culture with combined hyperexpression of BDNF and uPA and suppressed expression of Von Hippel-Lindau tumor suppressor even without additional concentration reduced the severity of neurological disorders and decreased brain lesion volume in the ICH model. The secretomes of MSCs with separate overexpression of BDNF and uPA or suppression of VHL had no such effect or, on the contrary, revealed a toxic effect in the ICH model. Presumably, this may be due to an imbalance in the representation of individual growth factors in the secretome of genetically modified MSCs, which individually may lead to undesirable effects in damaged nervous tissue, such as increased permeability of the blood-brain barrier (under the influence of pro-angiogenic factors) or neural cell apoptosis (due to an excess of neurotrophic factors). The obtained data show that genetic modification of MSC cultures can enhance or alter the therapeutic activity of their secretomes, which can be used in the creation of promising sources of biopharmaceutical substances.