Neural stem cell secretome exerts a protective effect on damaged neuron mitochondria in Parkinson's disease model.

Parkinson's disease (PD) is a common neurodegenerative disease. The main pathological changes are the loss of dopaminergic neurons and the formation of Lewy bodies. There is still no effective cure for PD, and cell replacement therapy has entered a bottleneck period due to tumorigenicity and rejection. Therefore, stem cell secretome has received widespread attention. However, the exploration of the secretome components of neural stem cells (NSCs) is still in its infancy. In this study, 6-hydroxydopamine (6-OHDA) was used to establish a PD rat model in vito and the PC12 cell-damaged model in vitro. The results indicated that the injection of neural stem cell-conditioned medium (NSC-CM) into the striatum and substantia nigra could improve the motor and non-motor deficits of PD rats and rescue the loss of dopaminergic neurons. In addition, NSC-CM alleviated 6-OHDA-induced apoptosis of PC12 cells, reduced the level of oxidative stress, and improved mitochondrial dysfunction in vitro. Parkinson disease protein 7 (Park7) was found in NSC-CM by Liquid chromatography-tandem mass spectrometry (LC-MS/MS), and it may be related to the protective effect of NSC-CM on 6-OHDA-injured neurons through Sirt1 pathway. In conclusion, NSC secretome might provide new ideas for the treatment of PD.

Human Neural Stem Cell Secretome Inhibits Lipopolysaccharide-Induced Neuroinflammation Through Modulating Microglia Polarization by Activating Peroxisome Proliferator-Activated Receptor Gamma.

Neuroinflammation is one of the typical events in multiple neurodegenerative diseases, whereas microglia are the critical participants in the pathogenesis of neuroinflammation. Several studies suggest that neural stem cells (NSCs) present immunomodulatory benefits due to their paracrine products, which contain mounting trophic factors. In the current study, the anti-inflammatory effects of NSC secretome (NSC-S) on lipopolysaccharide (LPS)-induced neuroinflammatory models were evaluated in vivo and the underlying mechanism was further investigated in vitro. It was revealed that NSC-S significantly attenuated the severity of LPS-induced behavior disorders and inflammatory response in mice. In vitro studies found that NSC-S significantly promoted the polarization of microglia from proinflammatory M1 to anti-inflammatory M2 phenotype, and reduced the production of proinflammatory cytokines, whereas elevated anti-inflammatory cytokines in BV2 cells. NSC-S promoted peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway activation. However, these effects of NSC-S were abrogated by PPAR-γ inhibitor GW9662. Notably, the fatty acid-binding protein 5 (FABP5) in NSC-S may mediate PPAR-γ activation and inflammation remission. In summary, NSC-S promotes the regression of LPS-induced microglia-mediated inflammation through the PPAR-γ pathway. This function might be achieved through FABP5.

Schwann-like cell conditioned medium promotes angiogenesis and nerve regeneration.

Vascular network reconstruction plays a pivotal role in the axonal regeneration and nerve function recovery after peripheral nerve injury. Increasing evidence indicates that Schwann cells (SCs) can promote nerve function repair, and the beneficial effects attributed to SCs therapy may exert their therapeutic effects through paracrine mechanisms. Recently, the previous research of our group demonstrated the promising neuroregenerative capacity of Schwann-like cells (SCLCs) derived from differentiated human embryonic stem cell-derived neural stem cells (hESC-NSCs) in vitro. Herein, the effects of SC-like cell conditioned medium (SCLC-CM) on angiogenesis and nerve regeneration were further explored. The assays were performed to show the pro-angiogenic effects of SCLC-CM, such as promoted endothelial cell proliferation, migration and tube formation in vitro. In addition, Sprague-Dawley rats were treated with SCLC-CM after sciatic nerve crush injury, SCLC-CM was conducive for the recovery of sciatic nerve function, which was mainly manifested in the SFI increase, the wet weight ratio of gastrocnemius muscle, as well as the number and thickness of myelin. The SCLC-CM treatment reduced the Evans blue leakage and increased the expression of CD34 microvessels. Furthermore, SCLC-CM upregulated the expressions of p-Akt and p-mTOR in endothelial cells. In conclusion, SCLC-CM promotes angiogenesis and nerve regeneration, it is expected to become a new treatment strategy for peripheral nerve injury.

Peroxiredoxin 6 secreted by Schwann-like cells protects neuron against ischemic stroke in rats via PTEN/PI3K/AKT pathway.

Schwann cells can promote the survival of damaged neurons and axon regeneration by secreting or releasing some proteins and factors which may provide effective strategies to the remedy for ischemic stroke. The models of middle cerebral artery occlusion and oxygen-glucose deprivation (OGD) were established. Peroxiredoxin 6 (PRDX6) was found in Schwann-like cell conditioned medium (SCLC-CM) by mass spectrometry. The rehabilitative performance of SCLC-CM on focal cerebral ischemia of rats and on OGD-induced PC12 cells were assessed. SCLC-CM significantly improved neurological recovery, reducing the infarct volume of rats after stroke. PRDX6 could significantly inhibit neuron apoptosis in the OGD injury by mediating oxidative stress and activating the PTEN/PI3K/AKT pathway. In conclusion, PRDX6 secreted by Schwann-like cell protects neuron against focal cerebral ischemia, SCLC-CM might be a new effective early intervention for ischemic stroke.

The antiandrogenic effect of neferine, liensinine, and isoliensinine by inhibiting 5-α-reductase and androgen receptor expression via PI3K/AKT signaling pathway in prostate cancer.

Neferine, liensinine, and isoliensinine are bisbenzylisoquinoline alkaloids extracted from seed-embryos of Nelumbo nucifera Gaertn. In this study, we evaluated the anticancer activities and mechanism of action of these natural products in prostate cancer cells by MTT, wound healing, ELISA and Western blotting. Neferine, liensinine, and isoliensinine showed growth inhibition and displayed a significant anti-migration activity in prostate cancer cells. They induced apoptosis and autophagy by activating cleaved caspase-9, cleaved PAPR, Bax, LC3B-II, but decreased Bcl-2 and PARP protein expression in LNCaP cells 24 h after treatments. The apoptotic and cytotoxic effects of neferine, liensinine, and isoliensinine were significantly attenuated in the presence of the caspase inhibitor, Z-VAD-FMK. However, the effects were enhanced in the presence of Akt inhibitor (MK2206) and PI3K inhibitor (LY294002). Moreover, neferine, liensinine, and isoliensinine also downregulated the protein expression of androgen receptor, prostate-specific antigen, and type II 5-α-reductase. These results demonstrated that these bisbenzylisoquinoline alkaloids have the potential as promising therapeutics agents. They induced apoptosis via inactivation with the PI3K/AKT signal pathway.

Microvesicles from Schwann-Like Cells as a New Biomaterial Promote Axonal Growth.

Schwann cells promote axonal regeneration following peripheral nerve injury. However, in terms of clinical treatment, the therapeutic effects of Schwann cells are limited by their source. The transmission of microvesicles from neuroglia cells to axons is a novel communication mechanism in axon regeneration.To evaluate the effect of microvesicles released from Schwann-like cells on axonal regeneration, neural stem cells derived from human embryonic stem cells differentiated into Schwann-like cells, which presented a typical morphology and characteristics similar to those of schwann cells. The glial markers like MBP, P0, P75NTR, PMP-22, GFAP, HNK-1 and S100 were upregulated, whereas the neural stem markers like NESTIN, SOX1 and SOX2 were significantly downregulated in schwann-like cells. Microvesicles enhanced axonal growth in dorsal root ganglia neurons and regulated GAP43 expression in neuron-like cells (N2A and PC12) through the PTEN/PI3 K/Akt signaling pathway. A 5 mm section of sciatic nerve was transected in Sprague-Dawley rats. With microvesicles transplantation, regenerative nerves were evaluated after 6 weeks. Microvesicles increased sciatic function index scores, delayed gastrocnemius muscle atrophy and elevated ßIII-tubulin-labeled axons in vivo. Schwann-like cells serve as a convenient source and promote axonal growth by secreting microvesicles, which may potentially be used as bioengineering materials for nerve tissue repair.

Human Neural Stem Cell-Conditioned Medium Inhibits Inflammation in Macrophages Via Sirt-1 Signaling Pathway In Vitro and Promotes Sciatic Nerve Injury Recovery in Rats.

Chronic persistent inflammation is thought to impede axon regeneration and cause demyelinating disease also with neuropathic pain, leading to more severe dysfunction after peripheral nerve injury. Increasing evidence indicates that neural stem cells (NSCs) have immunomodulatory effects, and previous studies have shown that many of the beneficial effects attributed to stem cell therapy may exert their therapeutic effects through paracrine mechanisms. In this research, the repairing effect of NSC-conditioned medium (NSC-CM) on sciatic nerve injury and its mechanism of repair were further explored. The present research showed that NSC-CM promoted histopathological and functional recovery after crush injury in rats, and what counts is that NSC-CM inhibited the inflammation of sciatic nerve in the late stage of injury. NSC-CM significantly downregulated the infiltration of proinflammatory factors [tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), and IL-1ß] as well as decreased the CD68 inflammatory macrophages infiltrating in the sciatic nerve. In addition, to study the effect of NSC-CM on the inflammatory state of macrophages in vitro, lipopolysaccharide (LPS) was used to induce the proinflammation of macrophages. The results showed that NSC-CM decreased the expression of macrophage proinflammatory-related proteins (IL-6, IL-1ß, TNF-α, inducible nitric oxide synthase) induced by LPS. The activation of Sirt-1 signaling in macrophages effectively countered the proinflammation induced by LPS in the presence of NSC-CM. Using Sirt-1-specific inhibitor EX527 partially weakened the anti-inflammatory effect of NSC-CM. Altogether, this study demonstrated for the first time that NSC-CM promotes functional recovery after sciatic nerve crush injury in vivo and also inhibits the inflammation in activated macrophages by activating Sirt-1 signaling pathway in vitro.

Attitude Angle Compensation for a Synchronous Acquisition Method Based on an MEMS Sensor.

As a new type of micro-electro-mechanical systems (MEMS) inertial sensor, the Quartz Vibrating Beam Accelerometer (QVBA) is widely used in intelligent sweeping robots, small aircraft, navigation systems, etc. For these applications, correcting and compensating the attitude angle with the result of acceleration plays an important role to improve the measurement accuracy. The synchronization error between the measurement of the accelerometer and gyroscope attitude angle has an adverse impact on the accuracy of the attitude angle. In this paper, a synchronous acquisition scheme of the accelerometer and gyroscope attitude angle in a strapdown inertial navigation system (SINS) is proposed. At the same time, to improve the sampling accuracy and the conversion speed of QVBA, an improved equal-precision frequency measuring method is also implemented in this paper. The hardware float point unit (FPU) is used to accelerate the calculation of the frequency measurement value. The long-term cumulative error of the frequency measurement value is less than 10 - 4 . The calculation process time from sampling to attitude angle compensation calculation is reduced by 40.8%. This work has played a very good role in improving the measurement accuracy and speed of the SINS.