Therapeutic Evaluation of Heat Shock Protein 20 Engineered Mesenchymal Stem Cells in a Rat Model of Spinal Cord Injury

Mesenchymal stem cells (MSCs) therapy is beneficial for treating spinal cord injury (SCI). The beneficial effects of MSCs are related to regeneration of axon, prevention of apoptosis and replacement of lost cells. Nevertheless, major impediments to their therapeutic application, such as low proliferation and survival rates remain as obstacles to broad clinical use of MSC. Recently, our laboratory has shown that treadmill exercise can inhibit cell apoptosis by improving the expression of heat shock protein (HSP) 72 and 20 in SCI rats (Please see Int. J. Mol. Sci. 2014, 15, 19018-19036). A more recent report has also demonstrated HSP20 is observed to be the most upregulated in the differentiated human adipose-derived stem cells, compared with other HSP’s, suggesting that HSP20 may play a critical role in stem cell differentiation. Several strategies have been proposed to augment the longevity of engrafted cells in the hostile ischemic environment. However, it remains unclear whether MSCs modified with a single HSP gene are able to augment their beneficial effects in treating SCI. In this study, we will genetically engineered rat MSCs with HSP20 gene (HSP20-MSCs), compared to green fluorescence protein (GFP)-modified MSCs (GFP-MSCs), and examined cell survival, neurogenesis, neuroinflammation modulation, and functional recovery in a rat model of SCI via intralesional injection. Here in, we attempt to conduct the following research plans: In the 1st year plan: We will ascertain whether HSP20-engineered MSCs afford better neuroprotection efficacy because they preferentially enhanced anti-inflammation and reduced cell apoptotic death of primary cortical cells in an oxygen-glucose deprivation (OGD) culture model that mimics the acute ischemic situation in humans. A co-cultured model of MSC and cortical neurons under ischemic condition will be performed. In the 2nd year plan: We will test whether the transplanted MSCs (with or without hsp20 overexpression) in a rat experimental spinal cord injury model improve outcome of SCI via anti-apoptosis and proneurogenesis. In addition, we will ascertain whether HSP20-MSCs can be incorporated into neurons or glial cells in ischemic brain area. In the 3rd year plan: We will investigate the roles played by neuroinflammation during the beneficial effects exerted by MSCs in treating SCI. Our current plans possess 3 folds of purposes. First, we aim to see whether HSP20-engineered MSCs are resistant to ischemic microenvironment in vitro. Second, we aim to ascertain whether virus-transfected HSP20 enhances therapeutic potency of transplanted MSCs in SCI rat via anti-apoptotic and pro-neurogenesis. Third, we aim to reveal the roles played by neuroinflammation in the proposed beneficial effects of HSP20-engineered MSCs in targeting SCI.