The matrix metalloproteinase inhibitor marimastat promotes neural progenitor cell differentiation into neurons by gelatinase-independent TIMP-2-dependent mechanisms

Glucocorticoids rescue cell surface trafficking of R451C Neuroligin3 and enhance synapse formation

Neuroligins are synaptic cell adhesion proteins with a role in synaptic function, implicated in neurodevelopmental disorders. The autism spectrum disorder-associated substitution Arg451Cys (R451C) in NLGN3 promotes a partial misfolding of the extracellular domain of the protein leading to retention in the endoplasmic reticulum (ER) and the induction of the unfolded protein response (UPR). The reduced trafficking of R451C NLGN3 to the cell surface leads to altered synaptic function and social behavior. A screening in HEK-293 cells overexpressing NLGN3 of 2662 compounds (FDA-approved small molecule drug library), led to the identification of several glucocorticoids such as alclometasone dipropionate, desonide, prednisolone sodium phosphate, and dexamethasone (DEX), with the ability to favor the exit of full-length R451C NLGN3 from the ER. DEX improved the stability of R451C NLGN3 and trafficking to the cell surface, reduced the activation of the UPR, and increased the formation of artificial synapses between HEK-293 and hippocampal primary neurons. The effect of DEX was validated on a novel model system represented by neural stem progenitor cells and differentiated neurons derived from the R451C NLGN3 knock-in mouse, expressing the endogenous protein. This work shows a potential rescue strategy for an autism-linked mutation affecting cell surface trafficking of a synaptic protein.

TIMP2 ameliorates blood-brain barrier disruption in traumatic brain injury by inhibiting Src-dependent VE-cadherin internalization

Blood-brain barrier (BBB) disruption is a serious pathological consequence of traumatic brain injury (TBI), for which there are limited therapeutic strategies. Tissue inhibitor of metalloproteinase-2 (TIMP2), a molecule with dual functions of inhibiting MMP activity and displaying cytokine-like activity through receptor binding, has been reported to inhibit VEGF-induced vascular hyperpermeability. Here, we investigate the ability of TIMP2 to ameliorate BBB disruption in TBI and the underlying molecular mechanisms. Both TIMP2 and AlaTIMP2, a TIMP2 mutant without MMP-inhibiting activity, attenuated neurological deficits and BBB leakage in TBI mice; they also inhibited junctional protein degradation and translocation to reduce paracellular permeability in human brain microvascular endothelial cells (ECs) exposed to hypoxic plus inflammatory insult. Mechanistic studies revealed that TIMP2 interacted with α3β1 integrin on ECs, inhibiting Src activation-dependent VE-cadherin phosphorylation, VE-cadherin/catenin complex destabilization, and subsequent VE-cadherin internalization. Notably, localization of VE-cadherin on the membrane was critical for TIMP2-mediated EC barrier integrity. Furthermore, TIMP2-mediated increased membrane localization of VE-cadherin enhanced the level of active Rac1, thereby inhibiting stress fiber formation. All together, our studies have identified an MMP-independent mechanism by which TIMP2 regulates EC barrier integrity after TBI. TIMP2 may be a therapeutic agent for TBI and other neurological disorders involving BBB breakdown.

A dual-targeting peptide facilitates targeting anti-inflammation to attenuate atherosclerosis in ApoE-/- mice

We report a peptidic dual-targeting drug delivery platform (integrins targeting and self-assembly instructed by matrix metalloproteinases) towards inflamed endothelial cells, which improved the anti-inflammatory ability of the loaded drug (i.e., puerarin) in vitro and thus improved the antiatherogenic effect of the loaded drug (i.e., puerarin) in vivo.

Wild-Type and Mutant FUS Expression Reduce Proliferation and Neuronal Differentiation Properties of Neural Stem Progenitor Cells

Nervous system development involves proliferation and cell specification of progenitor cells into neurons and glial cells. Unveiling how this complex process is orchestrated under physiological conditions and deciphering the molecular and cellular changes leading to neurological diseases is mandatory. To date, great efforts have been aimed at identifying gene mutations associated with many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Mutations in the RNA/DNA binding protein Fused in Sarcoma/Translocated in Liposarcoma (FUS/TLS) have been associated with motor neuron degeneration in rodents and humans. Furthermore, increased levels of the wild-type protein can promote neuronal cell death. Despite the well-established causal link between FUS mutations and ALS, its role in neural cells remains elusive. In order to shed new light on FUS functions we studied its role in the control of neural stem progenitor cell (NSPC) properties. Here, we report that human wild-type Fused in Sarcoma (WT FUS), exogenously expressed in mouse embryonic spinal cord-derived NSPCs, was localized in the nucleus, caused cell cycle arrest in G1 phase by affecting cell cycle regulator expression, and strongly reduced neuronal differentiation. Furthermore, the expression of the human mutant form of FUS (P525L-FUS), associated with early-onset ALS, drives the cells preferentially towards a glial lineage, strongly reducing the number of developing neurons. These results provide insight into the involvement of FUS in NSPC proliferation and differentiation into neurons and glia.

Harnessing Extracellular Matrix Biology for Tumor Drug Delivery

The extracellular matrix (ECM) plays an active role in cell life through a tightly controlled reciprocal relationship maintained by several fibrous proteins, enzymes, receptors, and other components. It is also highly involved in cancer progression. Because of its role in cancer etiology, the ECM holds opportunities for cancer therapy on several fronts. There are targets in the tumor-associated ECM at the level of signaling molecules, enzyme expression, protein structure, receptor interactions, and others. In particular, the ECM is implicated in invasiveness of tumors through its signaling interactions with cells. By capitalizing on the biology of the tumor microenvironment and the opportunities it presents for intervention, the ECM has been investigated as a therapeutic target, to facilitate drug delivery, and as a prognostic or diagnostic marker for tumor progression and therapeutic intervention. This review summarizes the tumor ECM biology as it relates to drug delivery with emphasis on design parameters targeting the ECM.

The 'rejuvenating factor' TIMP-2 is detectable in human blood components for transfusion

Background and Objectives

Tissue inhibitor of metalloproteinases 2 (TIMP‐2) is a protein suspected to be crucial in numerous physiological and pathological processes such as morphogenesis, tissue remodelling and metastasis suppression. In animal models, the administration of TIMP‐2 to aged mice improved their cognitive functions. Therefore, one can hypothesize that differences in TIMP‐2 levels between blood donors and recipients might influence cognitive functions also in humans. However, the stability of TIMP‐2 during processing and storage of blood components for transfusion has not been intensively investigated so far. This study determined TIMP‐2 concentrations in fresh‐frozen plasma (FFP), erythrocyte concentrate (EC) and pathogen‐inactivated platelet concentrate (PI‐PC) depending on the donor's demographic factors age and gender.

Materials and Methods

Tissue inhibitor of metalloproteinases 2 was measured in FFP (n = 30), EC (n = 12) and PI‐PC (n = 12) using a Q‐Plex single‐plex immunoassay for chemiluminescence‐based detection. Absolute quantification of TIMP‐2 was performed with Q‐view software. Fresh umbilical cord plasma was used as a positive control.

Results

Tissue inhibitor of metalloproteinases 2 was detected in FFP (30/30 samples), EC (11/12 samples) and PI‐PC (12/12 samples). The median TIMP‐2 concentration in EC (17·2 ng/ml; range: 0–26·5 ng/ml) was significantly lower compared with FFP (63·4 ng/ml; range: 44·4–87·3 ng/ml) or PI‐PC (69·9 ng/ml; range: 39·9–83·6 ng/ml). Across all blood components, TIMP‐2 levels are comparable in male and female donors and independent of age.

Conclusion

Tissue inhibitor of metalloproteinases 2 is detectable and stable in FFP, PI‐PC and, in low concentration, EC. It can be hypothesized that TIMP‐2 will be transmitted to recipients during transfusion.

Multiple Origins of Secretagogin Expressing Cortical GABAergic Neuron Precursors in the Early Human Fetal Telencephalon

Secretagogin (SCGN) which acts as a calcium signaling sensor, has previously been shown to be expressed by a substantial population of cortical GABAergic neurons at mid-gestation in humans but not in mice. The present study traced SCGN expression in cortical GABAergic neurons in human fetal forebrain from earlier stages than previously studied. Multiple potential origins of SCGN-expressing neurons were identified in the caudal ganglionic eminence (CGE) lateral ganglionic eminence (LGE) septum and preoptic area; these cells largely co-expressed SP8 but not the medial ganglionic eminence marker LHX6. They followed various migration routes to reach their target regions in the neocortex, insular and olfactory cortex (OC) and olfactory bulbs. A robust increase in the number of SCGN-expressing GABAergic cortical neurons was observed in the midgestational period; 58% of DLX2+ neurons expressed SCGN in the cortical wall at 19 post-conceptional weeks (PCW), a higher proportion than expressed calretinin, a marker for GABAergic neurons of LGE/CGE origin. Furthermore, although most SCGN+ neurons co-expressed calretinin in the cortical plate (CP) and deeper layers, in the marginal zone (MZ) SCGN+ and calretinin+ cells formed separate populations. In the adult mouse, it has previously been shown that in the rostral migratory stream (RMS), SCGN, annexin V (ANXA5), and matrix metalloprotease 2 (MMP2) are co-expressed forming a functioning complex that exocytoses MMP2 in response to calcium. In the present study, ANXA5 showed widespread expression throughout the cortical wall, although MMP2 expression was very largely limited to the CP. We found co-expression of these proteins in some SCGN+ neurons in the subventricular zones (SVZ) suggesting a limited role for these cells in remodeling the extracellular matrix, perhaps during cell migration.

Extracellular Vesicle-Induced Differentiation of Neural Stem Progenitor Cells

Neural stem progenitor cells (NSPCs) from E13.5 mouse embryos can be maintained in culture under proliferating conditions. Upon growth-factor removal, they may differentiate toward either neuronal or glial phenotypes or both. Exosomes are small extracellular vesicles that are part of the cell secretome; they may contain and deliver both proteins and genetic material and thus play a role in cell-cell communication, guide axonal growth, modulate synaptic activity and regulate peripheral nerve regeneration. In this work, we were interested in determining whether NSPCs and their progeny can produce and secrete extracellular vesicles (EVs) and if their content can affect cell differentiation. Our results indicate that cultured NSPCs produce and secrete EVs both under proliferating conditions and after differentiation. Treatment of proliferating NSPCs with EVs derived from differentiated NSPCs triggers cell differentiation in a dose-dependent manner, as demonstrated by glial- and neuronal-marker expression.

Increased FUS levels in astrocytes leads to astrocyte and microglia activation and neuronal death

Mutations of Fused in sarcoma (FUS), a ribonucleoprotein involved in RNA metabolism, have been found associated with both familial and sporadic cases of amyotrophic lateral sclerosis (ALS). Notably, besides mutations in the coding sequence, also mutations into the 3′ untranslated region, leading to increased levels of the wild-type protein, have been associated with neuronal death and ALS pathology, in ALS models and patients. The mechanistic link between altered FUS levels and ALS-related neurodegeneration is far to be elucidated, as well as the consequences of elevated FUS levels in the modulation of the inflammatory response sustained by glial cells, a well-recognized player in ALS progression. Here, we studied the effect of wild-type FUS overexpression on the responsiveness of mouse and human neural progenitor-derived astrocytes to a pro-inflammatory stimulus (IL1β) used to mimic an inflammatory environment. We found that astrocytes with increased FUS levels were more sensitive to IL1β, as shown by their enhanced expression of inflammatory genes, compared with control astrocytes. Moreover, astrocytes overexpressing FUS promoted neuronal cell death and pro-inflammatory microglia activation. We conclude that overexpression of wild-type FUS intrinsically affects astrocyte reactivity and drives their properties toward pro-inflammatory and neurotoxic functions, suggesting that a non-cell autonomous mechanism can support neurodegeneration in FUS-mutated animals and patients.

Targeting intracellular MMPs efficiently inhibits tumor metastasis and angiogenesis

Treatment for metastatic cancer is a great challenge throughout the world. Commonly, directed inhibition of extracellular matrix metalloproteinases (MMPs) secreted by cancer cells can reduce metastasis. Here, a novel nanoplatform (HPMC NPs) assembled from hyaluronic acid (HA)-paclitaxel (PTX) prodrug and marimastat (MATT)/β-casein (CN) complexes was established to cure a 4T1 metastatic cancer model via targeting CD44 and intracellular, rather than extracellular, MMPs.

Methods: HPMC NPs were prepared by assembling the complexes and prodrug under ultrasonic treatment, which the interaction between them was evaluated by förster resonance energy transfer, circular dichroism and fluorescence spectra. The developed nanoplatform was characterized via dynamic light scattering and transmission electron microscopy, and was evaluated in terms of MMP-sensitive release and stability. Subsequently, the cellular uptake, trafficking, and in vitro invasion were studied by flow cytometry, confocal laser microscopy and transwell assay. MMP expression and activity was determined by western blotting and gelatin zymography. Finally, the studies of biodistribution and antitumor efficacy in vivo were performed in a mouse 4T1 tumor breast model, followed by in vivo safety study in normal mouse.

Results: The interaction between the prodrug and complexes is strong with a high affinity, resulting in the assembly of these two components into hybrid nanoparticles (250 nm). Compared with extracellular incubation with MATT, HPMC NP treatment markedly reduced the expression (100%) and activity (50%) of MMPs in 4T1 cells and in the tumor. HPMC NPs exhibited 1.4-fold tumor accumulation, inhibited tumor-growth by >8-fold in volume with efficient apoptosis and proliferation, and suppressed metastasis (>5-fold) and angiogenesis (>3-fold). Overall, HPMC NPs were efficient in metastatic cancer therapy. Conclusions: According to the assembly of polymer prodrug and protein-drug complexes, this study offers a new strategy for constructing nanoparticles for targeted drug delivery, biomedical imaging, and combinatorial treatment. Importantly, via inhibition of intracellular MMPs, metastasis and angiogenesis can be potently blocked, benefiting the rational design of nanomedicine for cancer treatment.

Cellular Models for the Serpinopathies

Our current knowledge about the cellular mechanisms underlying serpin-related disorders, the serpinopathies, is predominantly based on studies in cell culture models of disease, particularly for alpha-1 antitrypsin (AAT, SERPINA1) deficiency causing emphysema and the familial encephalopathy with neuroserpin (NS, SERPINI1) inclusion bodies (FENIB). FENIB, a neurodegenerative dementia, is caused by polymerization of NS (Miranda and Lomas, Cell Mol Life Sci 63:709-722, 2006; Roussel BD et al., Epileptic Disor 18:103-110, 2016), while AAT deficiency presents as a result of several divergent mutations in the AAT gene that cause lack of protein synthesis or complete intracellular degradation (null variants) or polymer formation (polymerogenic variants) (Lomas et al., J Hepatol 65:413-424, 2016; Greene et al., Nat Rev Dis Primers 2:16051, 2016; Ferrarotti et al. Orphanet J Rare D 9:172, 2014). Both diseases have been extensively modeled in cell culture systems by expressing mutant variants in a variety of ways. Here we describe the methodologies we follow in our cell model systems used to examine serpin disorders.

Effects and mechanisms of matrix metalloproteinase2 on neural differentiation of induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) possess the potential to differentiate into neural lineage cells. Matrix metalloproteinase 2 (MMP2), an endopeptidase in the extracellular matrix, has been shown to protect neural cells from injury. However, the mechanisms and effects of MMP2 on neural differentiation of iPSCs remain poorly understood. Here, we demonstrated a role for MMP2 in the differentiation of iPSCs to neurons via the AKT pathway. Treatment of iPSCs with MMP2 promoted their proliferation and differentiation into neural stem cells (NSCs), and then into neurons. The transcript and protein expression of Nestin and microtubule-associated protein 2 (MAP2) increased. Moreover, MMP2 markedly induced the expression of phospho-AKT (pAKT) during these differentiation stages. Consistently, silencing MMP2 using siRNA attenuated the expression of Nestin, MAP2 and pAKT, compared with the control group. In addition, the increasing levels of Nestin, MAP2 and pAKT in the MMP2 group were declined by pretreatment with the phosphoinositide 3-kinase (PI3K)/AKT inhibitor, LY294002. Furthermore, the study detected that TrkA and TrkB were perhaps the potential receptors for these effects of MMP2 on neural differentiation through PI3K/AKT signaling pathway. Taken together, these results suggest that MMP2 induces the differentiation of iPSCs into neurons by regulating the AKT signaling pathway.

Neuroserpin polymers cause oxidative stress in a neuronal model of the dementia FENIB

The serpinopathies are human pathologies caused by mutations that promote polymerisation and intracellular deposition of proteins of the serpin superfamily, leading to a poorly understood cell toxicity. The dementia FENIB is caused by polymerisation of the neuronal serpin neuroserpin (NS) within the endoplasmic reticulum (ER) of neurons. With the aim of understanding the toxicity due to intracellular accumulation of neuroserpin polymers, we have generated transgenic neural progenitor cell (NPC) cultures from mouse foetal cerebral cortex, stably expressing the control protein GFP (green fluorescent protein), or human wild type, G392E or delta NS. We have characterised these cell lines in the proliferative state and after differentiation to neurons. Our results show that G392E NS formed polymers that were mostly retained within the ER, while wild type NS was correctly secreted as a monomeric protein into the culture medium. Delta NS was absent at steady state due to its rapid degradation, but it was easily detected upon proteasomal block. Looking at their intracellular distribution, wild type NS was found in partial co-localisation with ER and Golgi markers, while G392E NS was localised within the ER only. Furthermore, polymers of NS were detected by ELISA and immunofluorescence in neurons expressing the mutant but not the wild type protein. We used control GFP and G392E NPCs differentiated to neurons to investigate which cellular pathways were modulated by intracellular polymers by performing RNA sequencing. We identified 747 genes with a significant upregulation (623) or downregulation (124) in G392E NS-expressing cells, and we focused our attention on several genes involved in the defence against oxidative stress that were up-regulated in cells expressing G392E NS (Aldh1b1, Apoe, Gpx1, Gstm1, Prdx6, Scara3, Sod2). Inhibition of intracellular anti-oxidants by specific pharmacological reagents uncovered the damaging effects of NS polymers. Our results support a role for oxidative stress in the cellular toxicity underlying the neurodegenerative dementia FENIB.

Protease Expression Levels in Prostate Cancer Tissue Can Explain Prostate Cancer-Associated Seminal Biomarkers-An Explorative Concept Study

Previously, we described prostate cancer (PCa) detection (83% sensitivity; 67% specificity) in seminal plasma by CE-MS/MS. Moreover, advanced disease was distinguished from organ-confined tumors with 80% sensitivity and 82% specificity. The discovered biomarkers were naturally occurring fragments of larger seminal proteins, predominantly semenogelin 1 and 2, representing endpoints of the ejaculate liquefaction. Here we identified proteases putatively involved in PCa specific protein cleavage, and examined gene expression and tissue protein levels, jointly with cell localization in normal prostate (nP), benign prostate hyperplasia (BPH), seminal vesicles and PCa using qPCR, Western blotting and confocal laser scanning microscopy. We found differential gene expression of chymase (CMA1), matrix metalloproteinases (MMP3, MMP7), and upregulation of MMP14 and tissue inhibitors (TIMP1 and TIMP2) in BPH. In contrast tissue protein levels of MMP14 were downregulated in PCa. MMP3/TIMP1 and MMP7/TIMP1 ratios were decreased in BPH. In seminal vesicles, we found low-level expression of most proteases and, interestingly, we also detected TIMP1 and low levels of TIMP2. We conclude that MMP3 and MMP7 activity is different in PCa compared to BPH due to fine regulation by their inhibitor TIMP1. Our findings support the concept of seminal plasma biomarkers as non-invasive tool for PCa detection and risk stratification.

Drug target identification at the crossroad of neuronal apoptosis and survival

INTRODUCTION

Inappropriate activation of apoptosis may contribute to neurodegeneration, a multifaceted process that results in various chronic disorders, including Alzheimer's and Parkinson's diseases. Several in vitro and in vivo studies demonstrated that neuronal apoptosis is a multi-pathway cell-death program that requires RNA synthesis. Thus, transcriptionally activated genes whose products induce cell death can be triggered by different stimuli and antagonized by neurotrophic factors. Systems biology is now unveiling the series of intracellular signaling pathways and key drug targets at the intersection of neuronal apoptosis and survival. Areas covered: This review introduces a genomic approach that can be used to elucidate the systems biology of neuronal apoptosis and survival, and to rationally select drug targets, no longer oriented to emulate the action of growth factors at the membrane receptor level, but rather to modulate their downstream signals. Expert opinion: The advent of genomics is offering an unprecedented opportunity to explore how the delicate balance between apoptosis and survival-inducing signals triggers a transcriptional program. Characterization of this program can be useful to identify potential pharmacological targets for existing drugs. Such knowledge might pave the way towards an innovative pharmacology.

Regenerative repair of Pifithrin-α in cerebral ischemia via VEGF dependent manner

Promoting regenerative repair, including neurogenesis and angiogenesis, may provide a new therapeutic strategy for treatment of stroke. P53, a well-documented transcription factor, has been reported to be involved in cerebral ischemia and also serves as an important regulator of vascular endothelial growth factor (VEGF). However, the role of p53 in endogenous regenerative repair after brain ischemia is poorly understood. In this study, we investigated the effects of PFT-α, a specific p53 inhibitor on neurogenesis and angiogenesis improvement and associated signal pathways in rats impaired by cerebral artery occlusion (MCAo). PFT-α induced neuroprotection, reduced infarct volume and neurological functional impairment after ischemic stroke. More importantly, neurogenesis and angiogenesis were greatly enhanced by PFT-α, and accompanied by increased expression of VEGF. Moreover, we got consistent results in neural stem cells (NSCs) isolated from fetal rats. In contrast, application of the anti-VEGF neutralizing antibody (RB-222) partially reversed PFT-α-induced neuroprotection and rescued p53 expression. Noteworthily, inhibition of p53 after ischemic stroke in these rats improved their outcomes via promotion of regenerative repair. In conclusion, PFT-α could serve as a promising therapeutic strategy for ischemic stroke by promoting regenerative repair.

Mir-23a and mir-125b regulate neural stem/progenitor cell proliferation by targeting Musashi1

Musashi1 is an RNA binding protein that controls the neural cell fate, being involved in maintaining neural progenitors in their proliferative state. In particular, its downregulation is needed for triggering early neural differentiation programs. In this study, we profiled microRNA expression during the transition from neural progenitors to differentiated astrocytes and underscored 2 upregulated microRNAs, miR-23a and miR-125b, that sinergically act to restrain Musashi1 expression, thus creating a regulatory module controlling neural progenitor proliferation.

Protective Effects and Mechanisms of Salvianolic Acid B Against H₂O₂-Induced Injury in Induced Pluripotent Stem Cell-Derived Neural Stem Cells

Induced pluripotent stem cells (iPSCs) have the potential to differentiate into neural lineages. Salvianolic acid B (Sal B) is a commonly used, traditional Chinese medicine for enhancing neuroprotective effects, and has antioxidant, anti-inflammatory, and antiapoptotic properties. Here, we explore the potential mechanism of Sal B in protecting iPSC-derived neural stem cells (NSCs) against H2O2-induced injury. iPSCs were induced into NSCs, iPSC-derived NSCs were treated with 50 μM Sal B for 24.5 h and 500 μM H2O2 for 24 h. The resulting effects were examined by flow cytometry analysis, quantitative reverse-transcription polymerase chain reaction, and western blotting. Upon H2O2 exposure, Sal B significantly promoted cell viability and stabilization of the mitochondrial membrane potential. Sal B also visibly decreased the cell apoptotic ratio. In addition, Sal B markedly reduced expression of matrix metalloproteinase (MMP)-2 and -9, and phosphospecific signal transducer and activator of transcription 3 (p-STAT3), and increased the level of tissue inhibitor of metalloproteinase (TIMP)-2 in iPSC-derived NSCs induced by H2O2. These results suggest that Sal B protects iPSC-derived NSCs against H2O2-induced oxidative stress. The mechanisms of this stress tolerance may be attributed to modulation of the MMP/TIMP system and inhibition of the STAT3 signaling pathway.

RE1 silencing transcription factor/neuron-restrictive silencing factor regulates expansion of adult mouse subventricular zone-derived neural stem/progenitor cells in vitro

Adult neural stem cell (aNSC) activity is tuned by external stimuli through the recruitment of transcription factors. This study examines the RE1 silencing transcription factor (REST) in neural stem/progenitor cells isolated from the subventricular zone of adult mouse brain and provides the first extensive characterization of REST-mediated control of the cellular and molecular properties. This study shows that REST knockdown affects the capacity of progenitor cells to generate neurospheres, reduces cell proliferation, and triggers cell differentiation despite the presence of growth factors. Genome- and transcriptome-wide analyses show that REST binding sites are significantly enriched in genes associated with synaptic transmission and nervous system development and function. Seeking candidate regulators of aNSC function, this study identifies a member of the bone morphogenetic protein (BMP) family, BMP6, the mRNA and protein of which increased after REST knockdown. The results of this study extend previous findings, demonstrating a reciprocal control of REST expression by BMPs. Administration of exogenous BMP6 inhibits aNSC proliferation and induces the expression of the astrocytic marker glial fibrillary acidic protein, highlighting its antimitogenic and prodifferentiative effects. This study suggests that BMP6 produced in a REST-regulated manner together with other signals can contribute to regulation of NSC maintenance and fate.

Multifaceted roles of BDNF and FGF2 in human striatal primordium development. An in vitro study

Grafting fetal striatal cells into the brain of Huntington's disease (HD) patients has raised certain expectations in the past decade as an effective cell-based-therapy for this devastating condition. We argue that the first requirement for successful transplantation is defining the window of plasticity for the striatum during development when the progenitor cells, isolated from their environment, are able to maintain regional-specific-identity and to respond appropriately to cues. The primary cell culture from human fetal striatal primordium described here consists of a mixed population of neural stem cells, neuronal-restricted progenitors and striatal neurons. These cells express trophic factors, such as BDNF and FGF2. We show that these neurotrophins maintain cell plasticity, inducing the expression of neuronal precursor markers and cell adhesion molecules, as well as promoting neurogenesis, migration and survival. We propose that BDNF and FGF2 play an important autocrine-paracrine role during early striatum development in vivo and that their release by fetal striatal grafts may be relevant in the setting of HD cell therapy.

Epithelial-mesenchymal transition in colorectal cancer tissue of patients with Lynch syndrome

AIM: To explore the epithelial-mesenchymal transition (EMT) in tissue from patients with Lynch syndrome, and to interpret biological behaviour of Lynch syndrome.

METHODS: Sixty-eight formalin-fixed and paraffin embedded tissue blocks were analyzed in this study, including tissues from Lynch syndrome (n = 30), sporadic colorectal carcinoma (CRC) (n = 30), and tumor-adjacent tissues (n = 8). Tissue sections were stained for human mutS homolog 2 (hMSH2), human mutL homolog 1 (hMLH1), transforming growth factor-β type II receptor (TGFβRII), E-cadherin, β-catenin, matrix metalloproteinase-7 (MMP-7) and tissue inhibitor of metalloproteinase-2 (TIMP-2) by immunohistochemical staining. Furthermore, clinical data such as age, gender and tumor-node-metastasis stage were also collected retrospectively.

RESULTS: The positive expression rates of hMSH2, hMLH1, TGFβRII, E-cadherin, β-catenin, MMP-7 and TIMP-2 were significantly related to the depth of invasion and lymph node metastasis, but not to sex or tumour size or location. The differences in the positive expression rates of hMSH2, hMLH1, TGFβRII, E-cadherin, cytomembrane β-catenin, cytoplasmic β-catenin, MMP-7 and TIMP-2 were significant between sporadic CRC and Lynch syndrome. The expression of hMSH2 had a positive correlation with that of hMLH1 in Lynch syndrome and sporadic CRC. The expression of TGFβRII had a positive correlation with that of hMSH2, hMLH1 and MMP-7, and a negative correlation with that of TIMP-2. The expression of MMP-7 had a negative correlation with that of TIMP-2 in Lynch syndrome and sporadic CRC. The expression of E-cadherin was positively correlated with that of cytomembrane β-catenin. However, the expression of cytomembrane β-catenin was negatively correlated with that of cytoplasmic β-catenin, and the expression of cytoplasmic β-catenin was positively correlated with that of MMP-7.

CONCLUSION: EMT may play an important role in the development and progression of Lynch syndrome. Lynch syndrome was caused by the mutations of mismatch repair genes, mainly hMSH2 and hMLH1, which also beget the mutational inactivation of TGFβRII. Therefore, the colorectal cancer of Lynch syndrome can escape the inhibitory effect of TGFβ1. However, TGFβ1 can up-regulate the expression of MMP-7 and down-regulate the expression of TIMP-2 in tumors by disassembling the E-cadherin/β-catenin complex in the cytomembrane.