Robust Generation of Ready-to-Use Cryopreserved Motor Neurons from Human Pluripotent Stem Cells for Disease Modeling.

Human pluripotent stem cell (hPSC)-derived motor neurons (MNs) act as models for motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS) or spinal muscular atrophy. However, the MN differentiation efficiency and viability following cryopreservation require further development for application in large-scale studies and drug screening. Here, we developed a robust protocol to convert hPSCs into MN cryopreservation stocks (hPSCs were converted into >92% motor neural progenitors and >91% MNs). Near-mature MNs were cryopreserved at a high thawing survival rate and 89% MN marker expression on day 32. Moreover, these MNs exhibited classical electrophysiological properties and neuromuscular junction (NMJ) formation ability within only 4−6 days after thawing. To apply this platform as an MND model, MN stocks were generated from SOD1G85R, SOD1G85G isogenic control, and sporadic ALS hPSC lines. The thawed ALS MNs expressed ALS-specific cytopathies, including SOD1 protein aggregation and TDP-43 redistribution. Thus, a stable and robust protocol was developed to generate ready-to-use cryopreserved MNs without further neuronal maturation processes for application in MND mechanistic studies, NMJ model establishment, and large-scale drug screening.

Anti-Excitotoxic Effects of N-Butylidenephthalide Revealed by Chemically Insulted Purkinje Progenitor Cells Derived from SCA3 iPSCs.

Spinocerebellar ataxia type 3 (SCA3) is characterized by the over-repetitive CAG codon in the ataxin-3 gene (ATXN3), which encodes the mutant ATXN3 protein. The pathological defects of SCA3 such as the impaired aggresomes, autophagy, and the proteasome have been reported previously. To date, no effective treatment is available for SCA3 disease. This study aimed to study anti-excitotoxic effects of n-butylidenephthalide by chemically insulted Purkinje progenitor cells derived from SCA3 iPSCs. We successfully generated Purkinje progenitor cells (PPs) from SCA3 patient-derived iPSCs. The PPs, expressing both neural and Purkinje progenitor's markers, were acquired after 35 days of differentiation. In comparison with the PPs derived from control iPSCs, SCA3 iPSCs-derived PPs were more sensitive to the excitotoxicity induced by quinolinic acid (QA). The observations of QA-treated SCA3 PPs showing neural degeneration including neurite shrinkage and cell number decrease could be used to quickly and efficiently identify drug candidates. Given that the QA-induced neural cell death of SCA3 PPs was established, the activity of calpain in SCA3 PPs was revealed. Furthermore, the expression of cleaved poly (ADP-ribose) polymerase 1 (PARP1), a marker of apoptotic pathway, and the accumulation of ATXN3 proteolytic fragments were observed. When SCA3 PPs were treated with n-butylidenephthalide (n-BP), upregulated expression of calpain 2 and concurrent decreased level of calpastatin could be reversed, and the overall calpain activity was accordingly suppressed. Such findings reveal that n-BP could not only inhibit the cleavage of ATXN3 but also protect the QA-induced excitotoxicity from the Purkinje progenitor loss.

Targeting PSEN1 by lnc-CYP3A43-2/miR-29b-2-5p to Reduce ß Amyloid Plaque Formation and Improve Cognition Function.

Presenilin-1 (PSEN1) is a crucial subunit within the γ-secretase complex and regulates ß-amyloid (Aß) production. Accumulated evidence indicates that n-butylidenephthalide (BP) acts effectively to reduce Aß levels in neuronal cells that are derived from trisomy 21 (Ts21) induced pluripotent stem cells (iPSCs). However, the mechanism underlying this effect remains unclear. This article aims to investigate the possible mechanisms through which BP ameliorates the development of Alzheimer's disease (AD) and verify the effectiveness of BP through animal experiments. Results from RNA microarray analysis showed that BP treatment in Ts21 iPSC-derived neuronal cells reduced long noncoding RNA (lncRNA) CYP3A43-2 levels and increased microRNA (miR)-29b-2-5p levels. Bioinformatics tool prediction analysis, biotin-labeled miR-29b-2-5p pull-down assay, and dual-luciferase reporter assay confirmed a direct negative regulatory effect for miRNA29b-2-5p on lnc-RNA-CYP3A43-2 and PSEN1. Moreover, BP administration improved short-term memory and significantly reduced Aß accumulation in the hippocampus and cortex of 3xTg-AD mice but failed in miR-29b-2-5p mutant mice generated by CRISP/Cas9 technology. In addition, analysis of brain samples from patients with AD showed a decrease in microRNA-29b-2-5p expression in the frontal cortex region. Our results provide evidence that the LncCYP3A43-2/miR29-2-5p/PSEN1 network might be involved in the molecular mechanisms underlying BP-induced Aß reduction.

Pancreatic Adenocarcinoma Therapeutics Targeting RTK and TGF Beta Receptor.

Despite the improved overall survival rates in most cancers, pancreatic cancer remains one of the deadliest cancers in this decade. The rigid microenvironment, which majorly comprises cancer-associated fibroblasts (CAFs), plays an important role in the obstruction of pancreatic cancer therapy. To overcome this predicament, the signaling of receptor tyrosine kinases (RTKs) and TGF beta receptor (TGFßR) in both pancreatic cancer cell and supporting CAF should be considered as the therapeutic target. The activation of receptors has been reported to be aberrant to cell cycle regulation, and signal transduction pathways, such as growth-factor induced proliferation, and can also influence the apoptotic sensitivity of tumor cells. In this article, the regulation of RTKs/TGFßR between pancreatic ductal adenocarcinoma (PDAC) and CAFs, as well as the RTKs/TGFßR inhibitor-based clinical trials on pancreatic cancer are reviewed.

n-Butylidenephthalide Modulates Autophagy to Ameliorate Neuropathological Progress of Spinocerebellar Ataxia Type 3 through mTOR Pathway.

Spinocerebellar ataxia type 3 (SCA3), a hereditary and lethal neurodegenerative disease, is attributed to the abnormal accumulation of undegradable polyglutamine (polyQ), which is encoded by mutated ataxin-3 gene (ATXN3). The toxic fragments processed from mutant ATXN3 can induce neuronal death, leading to the muscular incoordination of the human body. Some treatment strategies of SCA3 are preferentially focused on depleting the abnormal aggregates, which led to the discovery of small molecule n-butylidenephthalide (n-BP). n-BP-promoted autophagy protected the loss of Purkinje cell in the cerebellum that regulates the network associated with motor functions. We report that the n-BP treatment may be effective in treating SCA3 disease. n-BP treatment led to the depletion of mutant ATXN3 with the expanded polyQ chain and the toxic fragments resulting in increased metabolic activity and alleviated atrophy of SCA3 murine cerebellum. Furthermore, n-BP treated animal and HEK-293GFP-ATXN3-84Q cell models could consistently show the depletion of aggregates through mTOR inhibition. With its unique mechanism, the two autophagic inhibitors Bafilomycin A1 and wortmannin could halt the n-BP-induced elimination of aggregates. Collectively, n-BP shows promising results for the treatment of SCA3.

Host pre-conditioning improves human adipose-derived stem cell transplantation in ageing rats after myocardial infarction: Role of NLRP3 inflammasome.

Functional decline of stem cell transplantation in ageing hosts is well documented. The mechanism for this is poorly understood, although it is known that advancing age does not provide an optimal milieu for exogenous stem cells to survive, engraft and differentiate. We showed that n-butylidenephthalide improved human adipose-derived stem cell (hADSC) engraftment via attenuating the production of reactive oxygen species (ROS). It remained unclear whether pre-treated hosts with n-butylidenephthalide can rejuvenate the ageing heart and improve hADSC engraftment by regulating the ROS/NLRP3 inflammasome-mediated cardiac fibrosis after myocardial infarction. One hour after coronary ligation, hADSCs were transplanted into the hearts of young and ageing Wistar rats that were pre-treated with or without n-butylidenephthalide for 3 days. At day 3 after infarction, myocardial infarction was associated with an increase in ROS levels and NLRP3 inflammasome activity with age. hADSC transplant effectively provided a significant decrease in ROS levels, NLRP3 inflammasome activity, IL-1ß levels and cardiac fibrosis in either young or old infarcted rats. However, the beneficial effects of hADSCs were greater in young compared with old rats in terms of NLRP3 inflammasome activity. The infarcted ageing rats pre-conditioned by n-butylidenephthalide improved engraftment and differentiation of hADSCs and additionally attenuated cardiac fibrosis compared with hADSCs alone. The anti-inflammation effects of n-butylidenephthalide were reversed by SIN-1. In conclusions, the increased NLRP3 inflammasome activity plays the pathogenesis of ageing-related functional hADSC decline in the ageing hosts. n-butylidenephthalide-pre-treated ageing hosts reversibly ameliorate the harsh microenvironments, improve stem cell engraftment and attenuate cardiac fibrosis after myocardial infarction.

Human-Induced Pluripotent Stem Cells and Herbal Small-Molecule Drugs for Treatment of Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by extracellular amyloid plaques composed of the ß-amyloid peptides and intracellular neurofibrillary tangles and associates with progressive declines in memory and cognition. Several genes play important roles and regulate enzymes that produce a pathological accumulation of ß-amyloid in the brain, such as gamma secretase (γ-secretase). Induced pluripotent stem cells from patients with Alzheimer's disease with different underlying genetic mechanisms may help model different phenotypes of Alzheimer's disease and facilitate personalized drug screening platforms for the identification of small molecules. We also discuss recent developments by γ-secretase inhibitors and modulators in the treatment of AD. In addition, small-molecule drugs isolated from Chinese herbal medicines have been shown effective in treating Alzheimer's disease. We propose a mechanism of small-molecule drugs in treating Alzheimer's disease. Combining therapy with different small-molecule drugs may increase the chance of symptomatic treatment. A customized strategy tailored to individuals and in combination with therapy may be a more suitable treatment option for Alzheimer's disease in the future.

N-Butylidenephthalide Inhibits the Phenotypic Switch of VSMCs through Activation of AMPK and Prevents Stenosis in an Arteriovenous Fistula Rat Model.

The phenotypic switch of vascular smooth muscle cells (VSMCs) plays a pivotal role in the development of vascular disorders, such as atherosclerosis, stenosis and restenosis, after vascular intervention. In our previous study, n-butylidenephthalide (BP) was reported to have anti-proliferating and apoptotic effects on VSMCs. The purpose of the current study is to further investigate its role in platelet-derived growth factor (PDGF)-induced VSMC phenotypic modulation in an arteriovenous fistula model. In vitro, we observed that BP inhibited the PDGF-induced cytoskeleton reorganization of the VSMCs. The enhanced expression of vimentin and collagen, as well as the migration ability induced by PDGF, were also inhibited by BP. By cell cycle analysis, we found that BP inhibited the PDGF-induced VSMCs proliferation and arrested the VSMCs in the G0/G1 phase. In an arteriovenous fistula rat model, the formation of stenosis, which was coupled with a thrombus, and the expression of vimentin and collagen in VSMCs, were also inhibited by administration of BP, indicating that BP inhibited the PDGF-induced phenotypic switch and the migration of VSMCs. Besides, the inhibitory effects of BP on the phenotypic switch were found to accompany the activated 5' AMP-activated protein kinase (AMPK) as well as the inhibited phosphorylation of mTOR. Knockdown of AMPK by gene silencing conflicted the effects of BP and further exacerbated the PDGF-induced VSMCs phenotypic switch, confirming the modulating effect that BP exerted on the VSMCs by this pathway. These findings suggest that BP may contribute to the vasculoprotective potential in vasculature.

Liposome Consolidated with Cyclodextrin Provides Prolonged Drug Retention Resulting in Increased Drug Bioavailability in Brain.

Although butylidenephthalide (BP) is an efficient anticancer drug, its poor bioavailability renders it ineffective for treating drug-resistant brain tumors. However, this problem is overcome through the use of noninvasive delivery systems, including intranasal administration. Herein, the bioavailability, drug stability, and encapsulation efficiency (EE, up to 95%) of BP were improved by using cyclodextrin-encapsulated BP in liposomal formulations (CDD1). The physical properties and EE of the CDD1 system were investigated via dynamic light scattering, transmission electron microscopy, UV-Vis spectroscopy, and nuclear magnetic resonance spectroscopy. The cytotoxicity was examined via MTT assay, and the cellular uptake was observed using fluorescence microscopy. The CDD1 system persisted for over 8 h in tumor cells, which was a considerable improvement in the retention of the BP-containing cyclodextrin or the BP-containing liposomes, thereby indicating a higher BP content in CDD1. Nanoscale CDD1 formulations were administered intranasally to nude mice that had been intracranially implanted with temozolomide-resistant glioblastoma multiforme cells, resulting in increased median survival time. Liquid chromatography-mass spectrometry revealed that drug biodistribution via intranasal delivery increased the accumulation of BP 10-fold compared to oral delivery methods. Therefore, BP/cyclodextrin/liposomal formulations have potential clinical applications for treating drug-resistant brain tumors.

Induced Pluripotent Stem Cell (iPSC)-Based Neurodegenerative Disease Models for Phenotype Recapitulation and Drug Screening.

Neurodegenerative diseases represent a significant unmet medical need in our aging society. There are no effective treatments for most of these diseases, and we know comparatively little regarding pathogenic mechanisms. Among the challenges faced by those involved in developing therapeutic drugs for neurodegenerative diseases, the syndromes are often complex, and small animal models do not fully recapitulate the unique features of the human nervous system. Human induced pluripotent stem cells (iPSCs) are a novel technology that ideally would permit us to generate neuronal cells from individual patients, thereby eliminating the problem of species-specificity inherent when using animal models. Specific phenotypes of iPSC-derived cells may permit researchers to identify sub-types and to distinguish among unique clusters and groups. Recently, iPSCs were used for drug screening and testing for neurologic disorders including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), spinocerebellar atrophy (SCA), and Zika virus infection. However, there remain many challenges still ahead, including how one might effectively recapitulate sporadic disease phenotypes and the selection of ideal phenotypes and for large-scale drug screening. Fortunately, quite a few novel strategies have been developed that might be combined with an iPSC-based model to solve these challenges, including organoid technology, single-cell RNA sequencing, genome editing, and deep learning artificial intelligence. Here, we will review current applications and potential future directions for iPSC-based neurodegenerative disease models for critical drug screening.

Preconditioned adipose-derived stem cells ameliorate cardiac fibrosis by regulating macrophage polarization in infarcted rat hearts through the PI3K/STAT3 pathway.

Stem cells can modify macrophage phenotypes; however, the mechanisms remain unclear. We investigated whether n-butylidenephthalide (BP) primed adipose-derived stem cells (ADSCs) attenuated cardiac fibrosis via regulating macrophage phenotype by a PI3K/STAT3-dependent pathway in postinfarcted rats. Male Wistar rats after coronary ligation were allocated to receive either intramyocardial injection of vehicle, ADSCs (1 × 106 cells), BP-preconditioned ADSCs, (BP + lithium)-preconditioned ADSCs, (BP + LY294002)-preconditioned ADSCs, and (BP + S3I-201)-preconditioned ADSCs. ADSCs were primed for 16 h before implantation. BP-pretreated ADSCs increased the cell viability compared with naive ADSCs in the in vitro experiments. Infarct sizes were similar among the infarcted groups at the acute and chronic stages of infarction. At day 3 after infarction, post-infarction was associated with increased M1 macrophage infiltration, which was inhibited by administering naive ADSCs. Compared with naive ADSCs, BP-preconditioned ADSCs provided a significant increase of Akt and STAT3 phosphorylation, STAT3 activity, STAT3 nuclear translocation, myocardial IL-10 levels, and the percentage of M2 macrophage infiltration. The effects of BP on M2 polarization were reversed by LY294002 or S3I-201. Furthermore, the phosphorylation of both Akt and STAT3 was abolished by LY294002, whereas Akt phosphorylation was not affected following the inhibition of STAT3. The addition of lithium did not have additional effects compared with BP alone. After 4 weeks of implantation, ADSCs remained in the myocardium, and reduced fibrosis and improved cardiac function. BP-preconditioned ADSCs provided superior cardioprotection, greater ADSC engraftment, and antifibrotic effects compared with naive ADSCs. These results suggest that BP-pretreated ADSCs polarize macrophages into M2 cells more efficiently than naive ADSCs via the PI3K/STAT3 pathway.

Epigenetic targeting DNMT1 of pancreatic ductal adenocarcinoma using interstitial control release biodegrading polymer reduced tumor growth through hedgehog pathway inhibition.

Annually, 48,000 people die from pancreatic ductal adenocarcinoma (PDAC), ranking it the fourth among cancer-related deaths in the United States. Currently, anti-cancer drugs are not effective against PDAC, and only extends survival by 3 months. Aberrant DNA methylation has been shown to play an important role during carcinogenesis in PDAC, with approximately 80% of tumor overexpressing the DNA methyltransferase 1 (DNMT1) protein. In the present study, we used DNMTs as a screening platform to find a new DNMT inhibitor, n-butylidenephthalide (n-BP), which is identified from a Chinese herbal drug. n-BP could inhibit DNMT1 expression in both dose-dependent and time-dependent manner. It also displays an effect in suppressing growth of PDAC cells and inducing cell cycle arrest at G0/G1 phase leading apoptosis. Growth suppression can be restored by the overexpression of DNMT1 in PDAC cells. Furthermore, we found n-BP-mediated DNMT1 suppression influenced the protein stability rather than changing the RNA expression. Through microarray studies, we found that the patched domain contained 4 (PTCHD4) is the potential downstream gene of DNMT1. Following silencing of PTCHD4 expression by siRNA, n-BP decreased tumor growth inhibition. Finally, in vivo, two animal models were used to evaluate the efficacy and survival after n-BP treatment by interstitial control release polymer delivery. The results show that n-BP could effectively inhibit PDAC tumor volume growth and extend animal survival. In summary, n-BP may inhibit the growth of human PDAC cells though reducing DNMT1 and increasing the expression of PTCHD4 both in vitro and in vivo.

Non-Canonical Regulation of Type I Collagen through Promoter Binding of SOX2 and Its Contribution to Ameliorating Pulmonary Fibrosis by Butylidenephthalide.

Pulmonary fibrosis is a fatal respiratory disease that gradually leads to dyspnea, mainly accompanied by excessive collagen production in the fibroblast and myofibroblast through mechanisms such as abnormal alveolar epithelial cells remodeling and stimulation of the extracellular matrix (ECM). Our results show that a small molecule, butylidenephthalide (BP), reduces type I collagen (COL1) expression in Transforming Growth Factor beta (TGF-ß)-induced lung fibroblast without altering downstream pathways of TGF-ß, such as Smad phosphorylation. Treatment of BP also reduces the expression of transcription factor Sex Determining Region Y-box 2 (SOX2), and the ectopic expression of SOX2 overcomes the inhibitory actions of BP on COL1 expression. We also found that serial deletion of the SOX2 binding site on 3'COL1 promoter results in a marked reduction in luciferase activity. Moreover, chromatin immunoprecipitation, which was found on the SOX2 binding site of the COL1 promoter, decreases in BP-treated cells. In an in vivo study using a bleomycin-induced pulmonary fibrosis C57BL/6 mice model, mice treated with BP displayed reduced lung fibrosis and collagen deposition, recovering in their pulmonary ventilation function. The reduction of SOX2 expression in BP-treated lung tissues is consistent with our findings in the fibroblast. This is the first report that reveals a non-canonical regulation of COL1 promoter via SOX2 binding, and contributes to the amelioration of pulmonary fibrosis by BP treatment.

Migration/Invasion of Malignant Gliomas and Implications for Therapeutic Treatment.

Malignant tumors of the central nervous system (CNS) are among cancers with the poorest prognosis, indicated by their association with tumors of high-level morbidity and mortality. Gliomas, the most common primary CNS tumors that arise from neuroglial stem or progenitor cells, have estimated annual incidence of 6.6 per 100,000 individuals in the USA, and 3.5 per 100,000 individuals in Taiwan. Tumor invasion and metastasis are the major contributors to the deaths in cancer patients. Therapeutic goals including cancer stem cells (CSC), phenotypic shifts, EZH2/AXL/TGF-ß axis activation, miRNAs and exosomes are relevant to GBM metastasis to develop novel targeted therapeutics for GBM and other brain cancers. Herein, we highlight tumor metastasis in our understanding of gliomas, and illustrate novel exosome therapeutic approaches in glioma, thereby paving the way towards innovative therapies in neuro-oncology.

Targeting the pathway of GSK-3ß/nerve growth factor to attenuate post-infarction arrhythmias by preconditioned adipose-derived stem cells.

Adipose-derived stem cell (ADSC) transplantation is a promising new therapy to improve cardiac function after myocardial infarction. However, its low efficacy of transdifferentiation hampers its usefulness. Glycogen synthase kinase-3ß (GSK-3ß) signal has been shown to play a role in preconditioning-induced cardioprotection. We assessed whether n-butylidenephthalide (BP) primed ADSCs can attenuate arrhythmias by a GSK-3ß-dependent pathway after myocardial infarction. Male Wistar rats after coronary ligation was randomly allocated to receive intramyocardial injection of vehicle, ADSCs, BP-preconditioned ADSCs, (BP+lithium)-preconditioned ADSCs, (BP+SB216763)-preconditioned ADSCs, and (BP+LY294002)-preconditioned ADSCs. ADSCs were primed for 16h before implantation. After 4weeks of implantation, ADSCs were retained in myocardium, reduced fibrosis and improved cardiac function. Sympathetic hyperinnervation was blunted after administering ADSCs, assessed by immunofluorescent analysis, and Western blotting and real-time quantitative RT-PCR of nerve growth factor. Arrhythmic scores during programmed stimulation in the ADSC-treated infarcted rats were significantly lower than vehicle. BP-preconditioned ADSCs had superior cardioprotection, greater ADSC engraftment and transdifferentiation, and antiarrhythmic effects compared with ADSCs alone. Simultaneously, BP increased the levels of phospho-Akt and down-regulated GSK-3ß activity. The effects of BP against sympathetic hyperinnervation were blocked by LY294002, a PI3K inhibitor. Addition of either lithium or SB216763 did not have additional effects compared with BP alone. Compared with ADSC alone, BP-primed ADSC implantation improved stem cell engraftment and attenuated sympathetic hyperinnervation and arrhythmias through a PI3K/Akt/GSK-3ß-dependent pathway, suggesting that a synergic action was achieved between BP pretreatment and ADSCs.

n-Butylidenephthalide Regulated Tumor Stem Cell Genes EZH2/AXL and Reduced Its Migration and Invasion in Glioblastoma.

Glioblastoma (GBM) is one of the most common and aggressive types of brain tumor. Due to its highly recurrent rate and poor prognosis, the overall survival time with this type of tumor is only 20-21 months. Recent knowledge suggests that its recurrence is in part due to the presence of cancer stem cells (CSCs), which display radioresistant, chemoresistant, self-renewal and tumorigenic potential. Enhancers of Zeste 2 (EZH2) and AXL receptor tyrosine kinase (AXL) are both highly expressed in GBM. Additionally, they are an essential regulator involved in CSCs maintenance, migration, invasion, epithelial-to-mesenchymal transition (EMT), stemness, metastasis and patient survival. In this study, we used a small molecule, n-butylidenephthalide (BP), to assess the anti-GBM stem-like cells potential, and then tried to find out the associated genes involved with regulation in migration and invasion. We demonstrated that BP reduced the expression of AXL and stemness related genes in a dose-dependent manner. The migratory and invasive capabilities of GBM stem-like cells could be reduced by AXL/EZH2. Finally, in the overexpression of AXL, EZH2 and Sox2 by transfection in GBM stem-like cells, we found that AXL/EZH2/TGF-ꞵ1, but not Sox2, might be a key regulator in tumor invasion, migration and EMT. These results might help in the development of a new anticancer compound and can be a target for treating GBM.

Antitumor and antimicrobial activity of some cyclic tetrapeptides and tripeptides derived from marine bacteria.

Marine derived cyclo(Gly-l-Ser-l-Pro-l-Glu) was selected as a lead to evaluate antitumor-antibiotic activity. Histidine was chosen to replace the serine residue to form cyclo(Gly-l-His-l-Pro-l-Glu). Cyclic tetrapeptides (CtetPs) were then synthesized using a solution phase method, and subjected to antitumor and antibiotic assays. The benzyl group protected CtetPs derivatives, showed better activity against antibiotic-resistant Staphylococcus aureus in the range of 60-120 µM. Benzyl group protected CtetPs 3 and 4, exhibited antitumor activity against several cell lines at a concentration of 80-108 µM. However, shortening the size of the ring to the cyclic tripeptide (CtriP) scaffold, cyclo(Gly-l-Ser-l-Pro), cyclo(Ser-l-Pro-l-Glu) and their analogues showed no antibiotic or antitumor activity. This phenomenon can be explained from their backbone structures.

Brain tumor senescence might be mediated by downregulation of S-phase kinase-associated protein 2 via butylidenephthalide leading to decreased cell viability.

Developing an effective drug for treating human glioblastoma multiform (GBM) has been investigated persistently. A pure compound butylidenephthalide (BP), isolated from Angelica sinensis, has been shown the activities to arrest the growth and initiate apoptosis of GBM in our previous reports. In this study, we further demonstrated that BP treatment accelerates the cell senescence in a dose-dependent manner in vitro and in vivo. S-phase kinase-associated protein 2 (Skp2), a proto-oncogene, is generally upregulated in cancer. We found that it was downregulated in BP-treated GBM cells. The downregulation of Skp2 is parallel with increasing p16 and p21 expression which causes G0/G1 arrest and tumor cell senescence. We also found that restoring the Skp2 protein level by exogenous overexpression prevents the BP-induced cell senescence. Therefore, the linkage between cell senescence and Skp2 expression is strengthened. Promoter binding analysis further detailed that the BP-mediated SP1 reduction might involve in the Skp2 downregulation. In summary, these results emphasize that BP-triggered senescence in GBM cells is highly associated with its control on Skp2 regulation.

CLEC5A is critical for dengue-virus-induced lethal disease.

Dengue haemorrhagic fever and dengue shock syndrome, the most severe responses to dengue virus (DV) infection, are characterized by plasma leakage (due to increased vascular permeability) and low platelet counts. CLEC5A (C-type lectin domain family 5, member A; also known as myeloid DAP12-associating lectin (MDL-1)) contains a C-type lectin-like fold similar to the natural-killer T-cell C-type lectin domains and associates with a 12-kDa DNAX-activating protein (DAP12) on myeloid cells. Here we show that CLEC5A interacts with the dengue virion directly and thereby brings about DAP12 phosphorylation. The CLEC5A-DV interaction does not result in viral entry but stimulates the release of proinflammatory cytokines. Blockade of CLEC5A-DV interaction suppresses the secretion of proinflammatory cytokines without affecting the release of interferon-alpha, supporting the notion that CLEC5A acts as a signalling receptor for proinflammatory cytokine release. Moreover, anti-CLEC5A monoclonal antibodies inhibit DV-induced plasma leakage, as well as subcutaneous and vital-organ haemorrhaging, and reduce the mortality of DV infection by about 50% in STAT1-deficient mice. Our observation that blockade of CLEC5A-mediated signalling attenuates the production of proinflammatory cytokines by macrophages infected with DV (either alone or complexed with an enhancing antibody) offers a promising strategy for alleviating tissue damage and increasing the survival of patients suffering from dengue haemorrhagic fever and dengue shock syndrome, and possibly even other virus-induced inflammatory diseases.

Engineered Exosomes Containing microRNA-29b-2 and Targeting the Somatostatin Receptor Reduce Presenilin 1 Expression and Decrease the ß-Amyloid Accumulation in the Brains of Mice with Alzheimer's Disease.

Purpose: Exosomes are membrane vesicles secreted by various cells and play a crucial role in intercellular communication. They can be excellent delivery vehicles for oligonucleotide drugs, such as microRNAs, due to their high biocompatibility. MicroRNAs have been shown to be more stable when incorporated into exosomes; however, the lack of targeting and immune evasion is still the obstacle to the use of these microRNA-containing nanocarriers in clinical settings. Our goal was to produce functional exosomes loaded with target ligands, immune evasion ligand, and oligonucleotide drug through genetic engineering in order to achieve more precise medical effects. Methods: To address the problem, we designed engineered exosomes with exogenous cholecystokinin (CCK) or somatostatin (SST) as the targeting ligand to direct the exosomes to the brain, as well as transduced CD47 proteins to reduce the elimination or phagocytosis of the targeted exosomes. MicroRNA-29b-2 was the tested oligonucleotide drug for delivery because our previous research showed that this type of microRNA was capable of reducing presenilin 1 (PSEN1) gene expression and decreasing the ß-amyloid accumulation for Alzheimer's disease (AD) in vitro and in vivo. Results: The engineered exosomes, containing miR29b-2 and expressing SST and CD47, were produced by gene-modified dendritic cells and used in the subsequent experiments. In comparison with CD47-CCK exosomes, CD47-SST exosomes showed a more significant increase in delivery efficiency. In addition, CD47-SST exosomes led to a higher delivery level of exosomes to the brains of nude mice when administered intravenously. Moreover, it was found that the miR29b-2-loaded CD47-SST exosomes could effectively reduce PSEN1 in translational levels, which resulted in an inhibition of beta-amyloid oligomers production both in the cell model and in the 3xTg-AD animal model. Conclusion: Our results demonstrated the feasibility of the designed engineered exosomes. The application of this exosomal nanocarrier platform can be extended to the delivery of other oligonucleotide drugs to specific tissues for the treatment of diseases while evading the immune system.