Center for the Advancement of Integrated Medical and Engineering Sciences (AIMES), Karolinska Institutet and KTH Royal Institute of Technology, 171 77, Stockholm, Sweden.
Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
Fluids Barriers CNS. 2022 Mar 17;19(1):22. doi: 10.1186/s12987-022-00315-1.
Neurodegenerative diseases (NDs) are an accelerating global health problem. Nevertheless, the stronghold of the brain- the blood-brain barrier (BBB) prevents drug penetrance and dwindles effective treatments. Therefore, it is crucial to identify Trojan horse-like drug carriers that can effectively cross the blood-brain barrier and reach the brain tissue. We have previously developed polyunsaturated fatty acids (PUFA)-based nanostructured lipid carriers (NLC), namely DHAH-NLC. These carriers are modulated with BBB-permeating compounds such as chitosan (CS) and trans-activating transcriptional activator (TAT) from HIV-1 that can entrap neurotrophic factors (NTF) serving as nanocarriers for NDs treatment. Moreover, microglia are suggested as a key causative factor of the undergoing neuroinflammation of NDs. In this work, we used in vitro models to investigate whether DHAH-NLCs can enter the brain via the BBB and investigate the therapeutic effect of NTF-containing DHAH-NLC and DHAH-NLC itself on lipopolysaccharide-challenged microglia.
We employed human induced pluripotent stem cell-derived brain microvascular endothelial cells (BMECs) to capitalize on the in vivo-like TEER of this BBB model and quantitatively assessed the permeability of DHAH-NLCs. We also used the HMC3 microglia cell line to assess the therapeutic effect of NTF-containing DHAH-NLC upon LPS challenge.
TAT-functionalized DHAH-NLCs successfully crossed the in vitro BBB model, which exhibited high transendothelial electrical resistance (TEER) values (≈3000 Ω*cm). Specifically, the TAT-functionalized DHAH-NLCs showed a permeability of up to 0.4% of the dose. Furthermore, using human microglia (HMC3), we demonstrate that DHAH-NLCs successfully counteracted the inflammatory response in our cultures after LPS challenge. Moreover, the encapsulation of glial cell-derived neurotrophic factor (GNDF)-containing DHAH-NLCs (DHAH-NLC-GNDF) activated the Nrf2/HO-1 pathway, suggesting the triggering of the endogenous anti-oxidative system present in microglia.
Overall, this work shows that the TAT-functionalized DHAH-NLCs can cross the BBB, modulate immune responses, and serve as cargo carriers for growth factors; thus, constituting an attractive and promising novel drug delivery approach for the transport of therapeutics through the BBB into the brain.
神经退行性疾病（NDs）是一个加速的全球健康问题。然而，大脑的堡垒——血脑屏障（BBB）阻止了药物穿透，减少了有效的治疗方法。因此，识别能够有效穿透血脑屏障并到达脑组织的特洛伊木马样药物载体至关重要。我们之前开发了基于多不饱和脂肪酸（PUFA）的纳米结构化脂质载体（NLC），即 DHAH-NLC。这些载体经过修饰，具有穿透 BBB 的化合物，如壳聚糖（CS）和来自 HIV-1 的转录激活因子（TAT），可以包埋神经营养因子（NTF），作为 NDs 治疗的纳米载体。此外，小胶质细胞被认为是 NDs 神经炎症发生的关键致病因素。在这项工作中，我们使用体外模型来研究 DHAH-NLC 是否可以通过 BBB 进入大脑，并研究含有 NTF 的 DHAH-NLC 和 DHAH-NLC 本身对脂多糖挑战的小胶质细胞的治疗效果。
我们使用人诱导多能干细胞衍生的脑微血管内皮细胞（BMECs）利用这种 BBB 模型的体内样 TEER，并定量评估 DHAH-NLC 的通透性。我们还使用 HMC3 小胶质细胞系评估含有 NTF 的 DHAH-NLC 在 LPS 挑战时的治疗效果。
TAT 功能化的 DHAH-NLC 成功穿过体外 BBB 模型，表现出高跨内皮电阻（TEER）值（≈3000 Ω*cm）。具体来说，TAT 功能化的 DHAH-NLC 的通透性高达剂量的 0.4%。此外，使用人小胶质细胞（HMC3），我们证明 DHAH-NLC 在 LPS 挑战后成功抑制了我们培养物中的炎症反应。此外，含有胶质细胞衍生神经营养因子（GNDF）的 DHAH-NLC 的包封（DHAH-NLC-GNDF）激活了 Nrf2/HO-1 通路，表明触发了小胶质细胞中存在的内源性抗氧化系统。
总的来说，这项工作表明 TAT 功能化的 DHAH-NLC 可以穿透 BBB，调节免疫反应，并作为生长因子的载体；因此，构成了一种有吸引力和有前途的新型药物输送方法，用于通过 BBB 将治疗剂输送到大脑。
