Membrane protein trafficking in the anti-tumor immune response: work of endosomal-lysosomal system.

Immunotherapy has changed the treatment landscape for multiple cancer types. In the recent decade, great progress has been made in immunotherapy, including immune checkpoint inhibitors, adoptive T-cell therapy, and cancer vaccines. ICIs work by reversing tumor-induced immunosuppression, resulting in robust activation of the immune system and lasting immune responses. Whereas, their clinical use faces several challenges, especially the low response rate in most patients. As an increasing number of studies have focused on membrane immune checkpoint protein trafficking and degradation, which interferes with response to immunotherapy, it is necessary to summarize the mechanism regulating those transmembrane domain proteins translocated into the cytoplasm and degraded via lysosome. In addition, other immune-related transmembrane domain proteins such as T-cell receptor and major histocompatibility are associated with neoantigen presentation. The endosomal-lysosomal system can also regulate TCR and neoantigen-MHC complexes on the membrane to affect the efficacy of adoptive T-cell therapy and cancer vaccines. In conclusion, we discuss the process of surface delivery, internalization, recycling, and degradation of immune checkpoint proteins, TCR, and neoantigen-MHC complexes on the endosomal-lysosomal system in biology for optimizing cancer immunotherapy.

Identification of CKD, bedridden history and cancer as higher-risk comorbidities and their impact on prognosis of hospitalized Omicron patients: a multi-centre cohort study.

To further describe the effect of the "fragile population" and their "higher-risk" comorbidities on prognosis among hospitalized Omicron patients, this observational cohort study enrolled hospitalized patients confirmed with SARS-CoV-2 during the 2022 Omicron wave in Shanghai, China. The primary outcome was progression to severe or critical cases. The secondary outcome was viral shedding time from the first positive SARS-CoV-2 detection. A total of 847 participants were enrolled, most of whom featured as advanced age (>70 years old: 30.34%), not fully vaccinated (55.84%), combined with at least 1 comorbidity (65.41%). Multivariate cox regression suggested age >70 years old (aHR[95%CI] 0.78[0.61-0.99]), chronic kidney disease (CKD) stage 4-5 (aHR[95%CI] 0.61[0.46-0.80]), heart conditions (aHR[95%CI] 0.76[0.60-0.97]) would elongate viral shedding time and fully/booster vaccination (aHR[95%CI] 1.4 [1.14-1.72]) would shorten this duration. Multivariate logistic regression suggested CKD stage 4-5 (aHR[95%CI] 3.21[1.45-7.27]), cancer (aHR[95%CI] 9.52[4.19-22.61]), and long-term bedridden status (aHR[95%CI] 4.94[2.36-10.44]) were the "higher" risk factor compared with the elderly, heart conditions, metabolic disorders, isolated hypertension, etc. for severity while female (aHR[95%CI] 0.34[0.16-0.68]) and fully/booster Vaccination (aHR[95%CI] 0.35[0.12-0.87]) could provide protection from illness progression. CKD stage 4-5, cancer and long-term bedridden history were "higher-risk" factors among hospitalized Omicron patients for severity progression while full vaccination could provide protection from illness progression.

Eliminating the original cargos of glioblastoma cell-derived small extracellular vesicles for efficient drug delivery to glioblastoma with improved biosafety.

Tumor derived small extracellular vesicles (TsEVs) display a great potential as efficient nanocarriers for chemotherapy because of their intrinsic targeting ability. However, the inherited risks of their original cargos (like loaded proteins or RNAs) from parent cancer cells in tumor progression severely hinder the practical application. In this study, a saponin-mediated cargo elimination strategy was established and practiced in glioblastoma (GBM) cell-derived small extracellular vesicles (GBM-sEVs). A high eliminating efficacy of the cargo molecules was confirmed by systematic analysis of the original proteins and RNAs in GBM-sEVs. In addition, the inherited functions of GBM-sEVs to promote GBM progression vanished after saponin treatment. Moreover, the results of cellular uptake analysis and in vivo imaging analysis demonstrated that saponin treatment preserved the homotypic targeting ability of GBM-sEVs. Thus, we developed an efficient nanocarrier with improved biosafety for GBM suppression. Furthermore, doxorubicin (DOX) transported by the saponin-treated GBM-sEVs (sa-GBM-sEVs) displayed an effective tumor suppression in both subcutaneous and orthotopic GBM models of mouse. Collectively, this study provides a feasible way to avoid the potential protumoral risks of TsEVs and can advance the clinical application of TsEVs in chemotherapy.

Human ESC-sEVs alleviate age-related bone loss by rejuvenating senescent bone marrow-derived mesenchymal stem cells.

Tissue-resident stem cell senescence leads to stem cell exhaustion, which is a major cause of physiological and pathological ageing. Stem cell-derived extracellular vesicles (SC-EVs) have been reported in preclinical studies to possess therapeutic potential for diverse diseases. However, whether SC-EVs can rejuvenate senescent tissue stem cells to prevent age-related disorders still remains unknown. Here, we show that chronic application of human embryonic stem cell-derived small extracellular vesicles (hESC-sEVs) rescues the function of senescent bone marrow mesenchymal stem cells (BM-MSCs) and prevents age-related bone loss in ageing mice. Transcriptome analysis revealed that hESC-sEVs treatment upregulated the expression of genes involved in antiaging, stem cell proliferation and osteogenic differentiation in BM-MSCs. Furthermore, liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified 4122 proteins encapsulated in hESC-sEVs. Bioinformatics analysis predicted that the protein components in the hESCs-sEVs function in a synergistic way to induce the activation of several canonical signalling pathways, including Wnt, Sirtuin, AMPK, PTEN signalling, which results in the upregulation of antiaging genes in BM-MSCs and then the recovery of senescent BM-MSCs function. Collectively, our findings reveal the effect of hESC-sEVs in reversing BM-MSCs senescence and age-related osteogenic dysfunction, thereby preventing age-related bone loss. Because hESC-sEVs could alleviate senescence of tissue-resident stem cells, they might be promising therapeutic candidates for age-related diseases.

Small extracellular vesicles secreted by human iPSC-derived MSC enhance angiogenesis through inhibiting STAT3-dependent autophagy in ischemic stroke.

BACKGROUND: Small extracellular vesicles (sEV) secreted by mesenchymal stem cells (MSC) derived from human induced pluripotent stem cells (iPSC, iMSC-sEV) are considered to have great potential in treating ischemic diseases. Angiogenesis play an important role in post-stroke recovery. However, no studies have yet been conducted to systemically examine the effect and the underlying mechanism of iMSC-sEV on angiogenesis under brain ischemia conditions. METHODS: Ischemic stroke model was performed in rats induced by middle cerebral artery occlusion (MCAO), and the pro-angiogenic capacity of iMSC-sEV was measured. The in vitro effects of iMSC-sEV on the migration and tube formation of endothelial cells were investigated, respectively. Autophagy and autophagy-related signaling pathway were detected in vivo and in vitro. RESULTS: We found that iMSC-sEV significantly reduced infarct volume, enhanced angiogenesis, and alleviated long-term neurological deficits in rats after stroke. We also demonstrated that iMSC-sEV increased migration and tube formation of endothelial cells in vitro. A further mechanism study revealed that the pro-angiogenic effect of iMSC-sEV was correlated with a reduction in autophagy. Furthermore, iMSC-sEV significantly activated signal transducer and activator of transcription 3 (STAT3), and suppression of STAT3 abolished iMSC-sEV-induced inhibition of autophagy and promotion of angiogenesis in vivo and in vitro. CONCLUSIONS: Taken together, our data indicate that iMSC-sEV promote angiogenesis after ischemic stroke, potentially, by inhibiting autophagy, a process that is partially dependent on STAT3 activation.

Human embryonic stem cell-derived exosomes promote pressure ulcer healing in aged mice by rejuvenating senescent endothelial cells.

BACKGROUND: Angiogenesis, as an endogenous repair mechanism, plays crucial roles in wound healing and tissue regeneration. However, this process is impaired in the elderly due to aging-related vascular endothelial dysfunction. This study was aimed to explore the pro-angiogenic effects of exosomes from human embryonic stem cells (ESC-Exos) in aged mice of pressure-induced ulcer model and the underlying mechanism. METHODS: Pressure ulcer wounds were created on the back of D-galactose-induced aging mice. ESC-Exos were locally applied onto the wound beds, with PBS as control. The effects of ESC-Exos on wound healing were analyzed by measuring wound closure rates, histological and immunofluorescence analyses. Then, the anti-aging effect of ESC-Exos on vascular endothelial cells was tested in an in vitro D-galactose-induced HUVEC senescence model. RESULTS: ESC-Exos could accelerate wound closure and enhance angiogenesis, and the senescence of vascular endothelial cells was significantly ameliorated after ESC-Exos treatment. In vitro, ESC-Exos could rejuvenate the senescence of endothelial cells and recover compromised proliferation, migratory capacity, and tube formation. This recovery was Nrf2-activation-dependent, since cotreatment with Nrf2 inhibitor Brusatol could abolish the rejuvenative effects of ESC-Exos. Further study revealed that miR-200a was highly enriched in ESC-Exos and played a crucial role in ESC-Exos-mediated rejuvenation through downregulating Keap1, which negatively regulates Nrf2 expression. CONCLUSIONS: ESC-Exos ameliorate endothelial senescence by activating Nrf2 and recover aging-related angiogenic dysfunction, thereby accelerating wound healing in aged mice. ESC-Exos might be a natural nano-biomaterial for aging-related diseases therapy.

Embryonic Stem Cells-Derived Exosomes Endowed with Targeting Properties as Chemotherapeutics Delivery Vehicles for Glioblastoma Therapy.

Exosomes are nanosized membrane vesicles (30-100 nm) that can easily penetrate the blood-brain barrier, safely deliver therapeutic drugs, and be modified with target ligands. Embryonic stem cells (ESCs) provide abundant exosome sources for clinical application due to their almost unlimited self-renewal. Previous studies show that exosomes secreted by ESCs (ESC-exos) have antitumor properties. However, it is not known whether ESC-exos inhibit glioblastoma (GBM) growth. In this study, the anti-GBM effect of ESC-exos is confirmed and then c(RGDyK)-modified and paclitaxel (PTX)-loaded ESC-exos, named cRGD-Exo-PTX are prepared. It is then investigated whether the engineered exosomes deliver more efficiently to GBM cells versus free drug alone and drug-loaded ESC-exos using an in vitro GBM model and in vivo subcutaneous and orthotopic xenografts model. The results show that cRGD-Exo-PTX significantly improves the curative effects of PTX in GBM via enhanced targeting. These data indicate that ESC-exos are potentially powerful therapeutic carriers for GBM and could have utility in many other diseases.

Apc gene suppresses intracranial aneurysm formation and rupture through inhibiting the NF-κB signaling pathway mediated inflammatory response.

Background: Intracranial aneurysm (IA) is a critical acquired cerebrovascular disease that may cause subarachnoid hemorrhage, and nuclear factor-κB (NF-κB)-mediated inflammation is involved in the pathogenesis of IA. Adenomatous polyposis coli (Apc) gene is a tumor suppressor gene associated with both familial and sporadic cancer. Herein, the purpose of our study is to validate effect of Apc gene on IA formation and rupture by regulating the NF-κB signaling pathway mediated inflammatory response. Methods: We collected IA specimens (from incarceration of IA) and normal cerebral arteries (from surgery of traumatic brain injury) to examine expression of Apc and the NF-κB signaling pathway related factors (NF-κB p65 and IκBα). ELISA was used to determine levels of monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß (IL-1ß), and IL-6. IA model was established in rats, and Apc-siRNA was treated to verify effect of Apc on IA formation and rupture. Next, regulation of Apc on the NF-κB signaling pathway was investigated. Results: Reduced expression of Apc and IκBα, and increased expression of NF-κB p65 were found in IA tissues. MCP-1, TNF-α, IL-1ß, and IL-6 exhibited higher levels in unruptured and ruptured IA, which suggested facilitated inflammatory responses. In addition, the IA rats injected with Apc-siRNA showed further enhanced activation of NF-κB signaling pathway, and up-regulated levels of MCP-1, TNF-α, IL-1ß, IL-6, MMP-2, and MMP-9 as well as extent of p65 phosphorylation in IA. Conclusion: Above all, Apc has the potential role to attenuate IA formation and rupture by inhibiting inflammatory response through repressing the activation of the NF-κB signaling pathway.

HP1α is highly expressed in glioma cells and facilitates cell proliferation and survival.

Epigenetic alteration plays critical roles in gliomagenesis by regulating gene expression through modifications of Histones and DNA. Trimethylation of H3K9, an essential repressed transcription mark, and one of its methyltransferase, SUV39H1, are implicated in glioma pathogenesis and progression. We find that the protein level of HP1α, a reader of H3K9me3 is elevated in GOS3 and 1321N1 glioma cell lines. H3K9me3 and SUV39H1 level are also upregulated. Depletion of HP1α and SUV39H1 weakens GOS3 and 1321N1 cell proliferation capacity and results in apoptosis of cells. Furthermore, we find that HP1α and H3K9me3 are enriched in the FAS and PUMA promoters, which suggests that upregulated HP1α and H3K9me3 prevent apoptosis by suppressing apoptotic activators. These data indicates that up-regulated HP1α, SUV39H1, and H3K9me3 in glioma cells are functionally associated with glioma pathogenesis and progression, and may serve as novel biomarkers for future diagnostic and therapeutic targeting of brain tumors.

HP1α is highly expressed in glioma cells and facilitates cell proliferation and survival.

Epigenetic alteration plays critical roles in gliomagenesis by regulating gene expression through modifications of Histones and DNA. Trimethylation of H3K9, an essential repressed transcription mark, and one of its methyltransferase, SUV39H1, are implicated in glioma pathogenesis and progression. We find that the protein level of HP1α, a reader of H3K9me3 is elevated in cultured glioma cell lines and glioma tissues. H3K9me3 is also upregulated. Depletion of HP1α and SUV39H1 weakens glioma cell proliferation capacity and results in apoptosis of cells. Furthermore, we find that HP1α and H3K9me3 are enriched in the FAS and PUMA promoters, which suggests that upregulated HP1α and H3K9me3 contribute to cell survival by suppressing apoptotic activators. These data suggests that up-regulated HP1α and H3K9me3 in glioma cells are functionally associated with glioma pathogenesis and progression and may serve as novel biomarkers for diagnostic and therapeutic targeting of brain tumors.

Role of Phosphorylated HDAC4 in Stroke-Induced Angiogenesis.

Acetylation or deacetylation of chromatin proteins and transcription factors is part of a complex signaling system that is involved in the control of neurological disorders. Recent studies have demonstrated that histone deacetylases (HDACs) exert protective effects in attenuating neuronal injury after ischemic insults. Class IIa HDAC4 is highly expressed in the brain, and neuronal activity depends on the nucleocytoplasmic shuttling of HDAC4. However, little is known about HDAC4 and its roles in ischemic stroke. In this study, we report that phosphorylation of HDAC4 was remarkably upregulated after stroke and blockade of HDAC4 phosphorylation with GÖ6976 repressed stroke-induced angiogenesis. Phosphorylation of HDAC4 was also increased in endothelial cells hypoxia model and suppression of HDAC4 phosphorylation inhibited the tube formation and migration of endothelial cells in vitro. Furthermore, in addition to the inhibition of angiogenesis, blockade of HDAC4 phosphorylation suppressed the expression of genes downstream of HIF-VEGF signaling in vitro and in vivo. These data indicate that phosphorylated HDAC4 may serve as an important regulator in stroke-induced angiogenesis. The protective mechanism of phosphorylated HDAC4 is associated with HIF-VEGF signaling, implicating a novel therapeutic target in stroke.

Targeting nasopharyngeal carcinoma by artesunate through inhibiting Akt/mTOR and inducing oxidative stress.

Drug repurposing has become an alternative therapeutic strategy for cancer treatment given the known pharmacokinetics and toxicity. The inhibitory effects of artesunate have been reported in various cancers. In this work, we investigated the effects of artesunate in nasopharyngeal carcinoma (NPC). We demonstrate that artesunate significantly inhibits proliferation via arresting NPC cells at G2/M phase. It also induces apoptosis through caspase-dependent and mitochondria-independent pathways in multiple NPC cell lines. The combination of artesunate and cisplatin is synergistic in targeting NPC cells in in vitro cellular culture system and in vivo xenograft tumor models. Artesunate inhibits phosphorylation of essential molecules involved in Akt/mTOR pathway in NPC cells, such as Akt, mTOR, and 4EBP1, and its inhibitory effects are partially abolished by overexpression of constitutively active Akt. In addition, artesunate also induces mitochondrial dysfunction and oxidative stress via inhibiting mitochondrial respiration, increasing levels of mitochondrial superoxide and cellular reactive oxygen species (ROS), leading to decreased ATP levels. Two ROS scavengers partially abolish the inhibitory effects of artesunate in NPC cells. These data suggest that both inhibition of Akt/mTOR pathway and induction of ROS are required for the action of artesunate in NPC cells. Our work demonstrates that artesunate is a potential candidate for NPC treatment. Our work also highlights the critical roles of Akt/mTOR pathway and mitochondrial function in NPC cells.

[RESEARCH PROGRESS OF MECHANISMS OF MESENCHYMAL STEM CELLS-DERIVED EXOSOMES IN TISSUE REPAIR].

OBJECTIVE: To review the mechanisms of bioactive substances of mesenchymal stem cells-derived exosomes (MEX) in tissue repair and analyze the therapeutic values of MEX. METHODS: Recent relevant literature about MEX for tissue repair was extensively reviewed and analyzed. RESULTS: The diameter of exosomes ranges from 30 to 100 nm which contain an abundance of bioactive substances, such as mRNA, microRNA, and protein. The majority of the exact bioactive substances in MEX, which are therapeutically beneficial to a wide range of diseases, are still unclear. CONCLUSION: Bioactive substances contained in the MEX have repairing effect in tissue injury, which could provide a new insight for the clinical treatment of tissue damage. However, further studies are required to investigate the individual differences of MEX and the possible risk of accelerating cancer progression of MEX.

Exosomes secreted by human-induced pluripotent stem cell-derived mesenchymal stem cells attenuate limb ischemia by promoting angiogenesis in mice.

INTRODUCTION: 'Patient-specific' induced pluripotent stem cells (iPSCs) are attractive because they can generate abundant cells without the risk of immune rejection for cell therapy. Studies have shown that iPSC-derived mesenchymal stem cells (iMSCs) possess powerful proliferation, differentiation, and therapeutic effects. Recently, most studies indicate that stem cells exert their therapeutic effect mainly through a paracrine mechanism other than transdifferentiation, and exosomes have emerged as an important paracrine factor for stem cells to reprogram injured cells. The objective of this study was to evaluate whether exosomes derived from iMSCs (iMSCs-Exo) possess the ability to attenuate limb ischemia and promote angiogenesis after transplantation into limbs of mice with femoral artery excision. METHODS: Human iPSCs (iPS-S-01, C1P33, and PCKDSF001C1) were used to differentiate into iMSCs in a modified one-step method. iMSCs were characterized by flow cytometry and multipotent differentiation potential analysis. Ultrafiltration combined with a purification method was used to isolate iMSCs-Exo, and transmission electron microscopy and Western blotting were used to identify iMSCs-Exo. After establishment of mouse hind-limb ischemia with excision of femoral artery and iMSCs-Exo injection, blood perfusion was monitored at days 0, 7, 14, and 21; microvessel density in ischemic muscle was also analyzed. In vitro migration, proliferation, and tube formation experiments were used to analyze the ability of pro-angiogenesis in iMSCs-Exo, and quantitative reverse-transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay were used to identify expression levels of angiogenesis-related molecules in human umbilical vein endothelial cells (HUVECs) after being cultured with iMSCs-Exo. RESULTS: iPSCs were efficiently induced into iMSC- with MSC-positive and -negative surface antigens and osteogenesis, adipogenesis, and chondrogenesis differentiation potential. iMSCs-Exo with a diameter of 57 ± 11 nm and expressed CD63, CD81, and CD9. Intramuscular injection of iMSCs-Exo markedly enhanced microvessel density and blood perfusion in mouse ischemic limbs, consistent with an attenuation of ischemic injury. In addition, iMSCs-Exo could activate angiogenesis-related molecule expression and promote HUVEC migration, proliferation, and tube formation. CONCLUSION: Implanted iMSCs-Exo was able to protect limbs from ischemic injury via the promotion of angiogenesis, which indicated that iMSCs-Exo may be a novel therapeutic approach in the treatment of ischemic diseases.

Repression of SIRT1 promotes the differentiation of mouse induced pluripotent stem cells into neural stem cells.

The use of transplanting functional neural stem cells (NSCs) derived from induced pluripotent stem cells (iPSCs) has increased for the treatment of brain diseases. As such, it is important to understand the molecular mechanisms that promote NSCs differentiation of iPSCs for future NSC-based therapies. Sirtuin 1 (SIRT1), a NAD(+)-dependent protein deacetylase, has attracted significant attention over the past decade due to its prominent role in processes including organ development, longevity, and cancer. However, it remains unclear whether SIRT1 plays a role in the differentiation of mouse iPSCs toward NSCs. In this study, we produced NSCs from mouse iPSCs using serum-free medium supplemented with retinoic acid. We then assessed changes in the expression of SIRT1 and microRNA-34a, which regulates SIRT1 expression. Moreover, we used a SIRT1 inhibitor to investigate the role of SIRT1 in NSCs differentiation of iPSCs. Data revealed that the expression of SIRT1 decreased, whereas miRNAs-34a increased, during this process. In addition, the inhibition of SIRT1 enhanced the generation of NSCs and mature neurocytes. This suggests that SIRT1 negatively regulated the differentiation of mouse iPSCs into NSCs, and that this process may be regulated by miRNA-34a.

Biological characteristics of human-urine-derived stem cells: potential for cell-based therapy in neurology.

Stem cells in human urine have gained attention in recent years; however, urine-derived stem cells (USCs) are far from being well elucidated. In this study, we compared the biological characteristics of USCs with adipose-derived stem cells (ASCs) and investigated whether USCs could serve as a potential cell source for neural tissue engineering. USCs were isolated from voided urine with a modified culture medium. Through a series of experiments, we examined the growth rate, surface antigens, and differentiation potential of USCs, and compared them with ASCs. USCs showed robust proliferation ability. After serial propagation, USCs retained normal karyotypes. Cell surface antigen expression of USCs was similar to ASCs. With lineage-specific induction factors, USCs could differentiate toward the osteogenic, chondrogenic, adipogenic, and neurogenic lineages. To assess the ability of USCs to survive, differentiate, and migrate, they were seeded onto hydrogel scaffold and transplanted into rat brain. The results showed that USCs were able to survive in the lesion site, migrate to other areas, and express proteins that were associated with neural phenotypes. The results of our study demonstrate that USCs possess similar biological characteristics with ASCs and have multilineage differentiation potential. Moreover USCs can differentiate to neuron-like cells in rat brain. The present study shows that USCs are a promising cell source for tissue engineering and regenerative medicine.

[The effect of hypertonic seawater and isotonic seawater for nasal mucosa of allergic rhinitis mice model].

OBJECTIVE: To study the effect of hypertonic seawater and isotonic seawater for nasal mucosa of allergic rhinitis mice model, and explore the possible mechanism of nasal irrigation with seawater in treatment of allergic rhinitis. METHOD: We used Der pl to make allergic rhinitis model of BALB/c mice, and divided them into three groups randomly. Nasal irrigation with hypertonic seawater (HS) or isotonic seawater (IS) in the treatment group 1-14 days after modeling, and black control (BC) group was given no treatment after modeling. Normal control (NC) group was given no treatment, the number of rubs and sneezings in each group were counted in 30 min after the last nasal irrigation. Mice were then killed 24 h after the last therapy. The noses of mice from each group were removed and fixed, then the slices were stained with hematoxylin and eosin, the others were observed by transmission electron microscope. RESULT: Mice with hypertonic seawater and isotonic seawater were significantly improved in rubs and sneezings compared to the black control group (P<0. 05); The number of eosinophiles in mucosal tissues of HS group and IS group had no significant difference with that of the black control group (P> 0. 05); Ciliated columnar epithelium cells in mucosal tissues of HS group and IS group were arranged trimly, better than that in the black control group. Morphology and microstructure in nasal mucosal of HS group was closer to the normal group than in IS group. CONCLUSION: The injury of nasal mucosa ciliated epithelium was significantly improved by nasal irrigation with hypertonic seawater and isotonic seawater, and the former is better than the latter, the mechanism of nasal irrigation with seawater in treatment of allergic rhinitis may rely on repairing the injured nasal mucosa ciliated epithelium, thereby the symptoms of nasal was reduced.

Distinct roles of neuregulin in different models of neuropathic pain.

The objective of the study was to investigate the role of neuregulin-ErbB signaling in neuropathic pain in different types of injury. Neuregulin-1(NRG-1) was injected into animals with either formalin-induced pain model or spared nerve injury (SNI) model. Formalin tests or paw withdrawal tests were performed to study the role of NRG-1 in neuropathic pain. siRNA specific to different erbB receptors were then introduced to test which specific signaling pathway was required for NRG-1 signaling in the different pain models. NRG-1 inhibits neuropathic pain after SNI in a dose-dependent manner, while NRG-1 aggravates formalin-induced neuropathic pain. ErbB2 and erbB4 receptors were activated after neuregulin administration. Knockdown of ErbB2 relieves the aggravation of NRG-1 on formalin-induced neuropathic pain, and knockdown of ErbB4 could relieve the inhibition of NRG-1 on neuropathic pain in the SNI model. NRG-1 has two distinct functions depending on the different receptor activation in different models of neuropathic pain. These novel findings may provide new therapeutic approaches for the treatment of neuropathic pain in different injury types.

Human induced pluripotent stem cell-derived neural stem cells survive, migrate, differentiate, and improve neurologic function in a rat model of middle cerebral artery occlusion.

INTRODUCTION: Stroke is a major cause of permanent neurologic damage, with few effective treatments available to restore lost function. Induced pluripotent stem cells (iPSCs) have the potential to generate all cell types in vitro and can be generated from a stroke patient. Therefore, iPSCs are attractive donor sources of genetically identical "patient-specific" cells to hold promise in therapy for stroke. In the present study, we established a four-stage culture system by using serum-free medium and retinoic acid (RA) to differentiate iPSCs into neural stem cells (NSCs) effectively and stably. Our hypothesis was that iPSC-derived NSCs would survive, migrate, and differentiate in vivo, and improve neurologic function after transplantation into the brains of rats with ischemic stroke. METHODS: Human iPSCs (iPS-S-01) and human ESCs (HuES17) were used to differentiate into NSCs by using our four-stage culture system. iPSCs and differentiated NSCs were characterized by immunocytochemistry staining and reverse transcription-polymerase chain reaction (RT-PCR) analysis. After establishment of focal cerebral ischemia with occlusion of the middle cerebral artery (MCA) and cell transplantation, animals were killed at 1 week and 2 weeks to analyze survival, migration, and differentiation of implanted cells in brain tissue. Animal behavior was evaluated via rope grabbing, beam walking, and Morris water maze tests. RESULTS: iPSCs were efficiently induced into NSCs by using a newly established four-stage induction system in vitro. iPSCs expressed pluripotency-associated genes Oct4, Sox2, and Nanog before NSC differentiation. The iPSC-derived NSCs spontaneously differentiated into neurons and astrocytes, which highly express ß-tubulin and glial fibrillary acidic protein (GFAP), respectively. On transplantation into the striatum, CM-DiI labeled iPSC-derived NSCs were found to migrate into the ischemia area at 1 week and 2 weeks, and animal-function recovery was significantly improved in comparison with control groups at 3 weeks. CONCLUSIONS: The four-stage induction system is stable and effective to culture, differentiate, and induce iPSCs to NSCs by using serum-free medium combined with retinoic acid (RA). Implanted iPSC-derived NSCs were able to survive, migrate into the ischemic brain area to differentiate into mature neural cells, and seem to have potential to restore lost neurologic function from damage due to stroke in a rat model.