Survival of motor neuron protein over-expression prevents calpain-mediated cleavage and activation of procaspase-3 in differentiated human SH-SY5Y cells

Analysis of the serum proteome profile of wild stump-tailed macaques (Macaca arctoides) seropositive for Zika virus antibodies in Thailand

Zika virus (ZIKV) is a member of the Flaviviridae virus family and poses a significant global health concern. ZIKV is transmitted by Aedes mosquitoes, and it has been implicated in various neurological conditions associated with fetal brain development. ZIKV has two transmission cycles: a sylvatic cycle in which nonhuman primates are infected via arboreal mosquito bites, and an interhuman (urban) cycle in which the virus is transmitted among primates by Aedes mosquitoes. ZIKV was first discovered in wild macaques, and the danger posed by the virus is increased due to the close proximity between humans and wild animals in modern society. However, data regarding the extent and role of infection in nonhuman primates are limited. Thus, there is an urgent need for improved surveillance, diagnostic methods, and public health interventions to effectively combat ZIKV transmission and its associated health impacts in Southeast Asia. In this study, we used a proteomics and bioinformatics approach to profile serum proteins in wild stump-tailed macaques seropositive for neutralizing antibodies against ZIKV. A total of 9,532 total proteins were identified, and 338 differentially expressed proteins were identified between naïve and seropositive animals. A total of 52 important proteins were used to construct a serum proteomic profile. These 52 important proteins were associated with immune and inflammatory responses (36.54%), neurological damage (23.08%), viral activities (21.15%), the apoptosis signaling pathway (9.61%), and other pathways (9.61%). Our proteomic profile identified proteins that inhibit the apoptosis pathway, intracellular resource competition with the virus, and neurological damage due to ZIKV and the host immune and defense responses.

The SH-SY5Y cell line: a valuable tool for Parkinson's disease drug discovery

INTRODUCTION

Owing to limited efficient treatment strategies for highly prevalent and distressing Parkinson's disease (PD), an impending need emerged for deciphering new modes and mechanisms for effective management. SH-SY5Y-based in vitro neuronal models have emerged as a new possibility for the elucidation of cellular and molecular processes in the pathogenesis of PD. SH-SY5Y cells are of human origin, adhered to catecholaminergic neuronal attributes, which consequences in imparting wide acceptance and significance to this model over conventional in vitro PD models for high-throughput screening of therapeutics.

AREAS COVERED

Herein, the authors review the SH-SY5Y cell line and its value to PD research. The authors also provide the reader with their expert perspectives on how these developments can lead to the development of new impactful therapeutics.

EXPERT OPINION

Encouraged by recent research on SH-SY5Y cell lines, it was envisaged that this in vitro model can serve as a primary model for assessing efficacy and toxicity of new therapeutics as well as for nanocarriers' capacity in delivering therapeutic agents across BBB. Considering the proximity with human neuronal environment as in pathogenic PD conditions, SH-SY5Y cell lines vindicated consistency and reproducibility in experimental results. Accordingly, exploitation of this standardized SH-SY5Y cell line can fast-track the drug discovery and development path for novel therapeutics.

Intracellular partners of fibroblast growth factors 1 and 2 - implications for functions

Fibroblast growth factors 1 and 2 (FGF1 and FGF2) are mainly considered as ligands of surface receptors through which they regulate a broad spectrum of biological processes. They are secreted in non-canonical way and, unlike other growth factors, they are able to translocate from the endosome to the cell interior. These unique features, as well as the role of the intracellular pool of FGF1 and FGF2, are far from being fully understood. An increasing number of reports address this problem, focusing on the intracellular interactions of FGF1 and 2. Here, we summarize the current state of knowledge of the FGF1 and FGF2 binding partners inside the cell and the possible role of these interactions. The partner proteins are grouped according to their function, including proteins involved in secretion, cell signaling, nucleocytoplasmic transport, binding and processing of nucleic acids, ATP binding, and cytoskeleton assembly. An in-depth analysis of the network of these binding partners could indicate novel, non-classical functions of FGF1 and FGF2 and uncover an additional level of a fine control of the well-known FGF-regulated cellular processes.

MiR-99a and MiR-491 Regulate Cisplatin Resistance in Human Gastric Cancer Cells by Targeting CAPNS1

Cisplatin is the first-line agent utilized for the clinical treatment of a wide variety of solid tumors including gastric cancer. However, the intrinsic or acquired cisplatin resistance is often occurred in patients with gastric cancer and resulted in failure of cisplatin therapy. In order to investigate if miRNA involves in cisplatin resistance of human gastric cancer, we first screened and compared the expression of miRNAs between cisplatin resistant gastric cancer cell lines SGC-7901/DDP and BGC-823/DDP and their sensitive parental cells by miRNAs microarray and followed by analysis of 2D-GE/MS to identify their target proteins. We found both miR-99a and miR-491 were upregulated while their target gene calpain small subunit 1 (CAPNS1) was downregulated in resistant gastric cancer cells. Dual-luciferase- reporter assays with wild-type and mutated CAPNS1 3'-UTR confirmed their specificity of targeting. Inhibition of miR-99a and miR-491, or overexpress CAPNS1 can enhance cisplatin sensitivity of the resistant cells while transfection of two miRNAs' mimics or si-CAPNS1 in the sensitive cells can induce their resistance. Moreover, our results demonstrated CAPNS1 positively regulated calpain1 and calpain2, the catalytic subunits of CAPNS1, and cleaved caspase3 which further cleaved PARP1 and directly induced apoptosis. Therefore, miR-99a and miR-491 might be work as novel molecules regulate cisplatin resistance by directly targeting CAPNS1 associated pathway in human gastric cancer cells.

Tetramethylpyrazine induces SH-SY5Y cell differentiation toward the neuronal phenotype through activation of the PI3K/Akt/Sp1/TopoIIβ pathway

Tetramethylpyrazine (TMP) is an active compound extracted from the traditional Chinese medicinal herb Chuanxiong. Previously, we have shown that TMP induces human SH-SY5Y neuroblastoma cell differentiation toward the neuronal phenotype by targeting topoisomeraseIIβ (TopoIIβ), a protein implicated in neural development. In the present study, we aimed to elucidate whether the transcriptional factors specificity protein 1 (Sp1) and nuclear factor Y (NF-Y), in addition to the upstream signaling pathways ERK1/2 and PI3K/Akt, are involved in modulating TopoIIβ expression in the neuronal differentiation process. We demonstrated that SH-SY5Y cells treated with TMP (80μM) terminally differentiated into neurons, characterized by increased neuronal markers, tubulin βIII and microtubule associated protein 2 (MAP2), and increased neurite outgrowth, with no negative effect on cell survival. TMP also increased the expression of TopoIIβ, which was accompanied by increased expression of Sp1 in the differentiated neuron-like cells, whereas NF-Y protein levels remained unchanged following the differentiation progression. We also found that the phosphorylation level of Akt, but not ERK1/2, was significantly increased as a result of TMP stimulation. Furthermore, as established by chromatin immunoprecipitation (ChIP) assay, activation of the PI3K/Akt pathway increased Sp1 binding to the promoter of the TopoIIβ gene. Blockage of PI3K/Akt was shown to lead to subsequent inhibition of TopoIIβ expression and neuronal differentiation. Collectively, the results indicate that the PI3K/Akt/Sp1/TopoIIβ signaling pathway is necessary for TMP-induced neuronal differentiation. Our findings offer mechanistic insights into understanding the upstream regulation of TopoIIβ in neuronal differentiation, and suggest potential applications of TMP both in neuroscience research and clinical practice to treat relevant diseases of the nervous system.

Investigation of a recombinant SMN protein delivery system to treat spinal muscular atrophy

Spinal muscular atrophy (SMA), the most common genetic cause of infant death, is a neurodegenerative disorder affecting motor neurons. SMA results from a loss in full-length survival of motor neuron (SMN) protein due to deletions/mutations in the SMN1 gene. In this study, we assessed the ability of cell-penetrating peptides (CPP) to deliver recombinant SMN protein to cultured neurons as a prelude for a potential therapeutic to treat SMA. Firstly, we confirmed that E. coli produced recombinant GFP protein fused to TAT (YGRKKRRQRRR; TAT-GFP) transduced rat cortical neurons in a concentration dependent manner. However, due to low yields of recombinant TATSMN protein obtainable from E. coli, we investigated the potential of a modified TAT (TATκ: YARKAARQARA) or R9 (RRRRRRRRR) peptide downstream of the fibronectin (FIB) secretory signal peptide to generate recombinant CPP-fused SMN protein. While U251 cells transduced with an adenoviral vector expressing CMV-FIB-TATκ-SMN secreted recombinant TATκ-SMN protein, we did not detect TATκ-SMN protein transduction of cortical neurons. Further, purified TATκ-SMN was unable to transduce SH-SY5Y cells, nor block apoptosis following LY294002 treatment of these cells. Our findings indicate that TATκ is not a suitable CPP to deliver SMN protein to neurons. Nonetheless, we have developed a novel method to generate full-length recombinant SMN protein using a mammalian expression system, which can be used to explore the application of other CPPs to deliver SMN protein as a treatment for SMA.

Spinal muscular atrophy and the antiapoptotic role of survival of motor neuron (SMN) protein

Spinal muscular atrophy (SMA) is a devastating and often fatal neurodegenerative disease that affects spinal motor neurons and leads to progressive muscle wasting and paralysis. The survival of motor neuron (SMN) gene is mutated or deleted in most forms of SMA, which results in a critical reduction in SMN protein. Motor neurons appear particularly vulnerable to reduced SMN protein levels. Therefore, understanding the functional role of SMN in protecting motor neurons from degeneration is an essential prerequisite for the design of effective therapies for SMA. To this end, there is increasing evidence indicating a key regulatory antiapoptotic role for the SMN protein that is important in motor neuron survival. The aim of this review is to highlight key findings that support an antiapoptotic role for SMN in modulating cell survival and raise possibilities for new therapeutic approaches.

Co-regulation of survival of motor neuron and Bcl-xL expression: implications for neuroprotection in spinal muscular atrophy

Spinal muscular atrophy (SMA), a fatal genetic motor disorder of infants, is caused by diminished full-length survival of motor neuron (SMN) protein levels. Normally involved in small nuclear ribonucleoprotein (snRNP) assembly and pre-mRNA splicing, recent studies suggest that SMN plays a critical role in regulating apoptosis. Interestingly, the anti-apoptotic Bcl-x isoform, Bcl-xL, is reduced in SMA. In a related finding, Sam68, an RNA-binding protein, was found to modulate splicing of SMN and Bcl-xL transcripts, promoting SMNΔ7 and pro-apoptotic Bcl-xS transcripts. Here we demonstrate that Bcl-xL expression increases SMN protein by ∼2-fold in SH-SY5Y cells. Conversely, SMN expression increases Bcl-xL protein levels by ∼6-fold in SH-SY5Y cells, and ∼2.5-fold in the brains of transgenic mice over-expressing SMN (PrP-SMN). Moreover, Sam68 protein levels were markedly reduced following SMN and Bcl-xL expression in SH-SY5Y cells, suggesting a feedback mechanism co-regulating levels of both proteins. We also found that exogenous SMN expression increased full-length SMN transcripts, possibly by promoting exon 7 inclusion. Finally, co-expression of SMN and Bcl-xL produced an additive anti-apoptotic effect following PI3-kinase inhibition in SH-SY5Y cells. Our findings implicate Bcl-xL as another potential target in SMA therapeutics, and indicate that therapeutic increases in SMN may arise from modest increases in total SMN.

Berberine activates Nrf2 nuclear translocation and protects against oxidative damage via a phosphatidylinositol 3-kinase/Akt-dependent mechanism in NSC34 motor neuron-like cells

Berberine (BBR) is a well-known anti-diabetic herbal medicine in Asia due to its beneficial effects on insulin sensitivity, glucose metabolism and glycolysis. Here, we identified the critical role of phosphatidylinositol 3-kinase (PI3K)/Akt involved BBR cellular defense mechanisms and first revealed the novel effect of BBR on nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2)/heme oxygenase (HO)-1 induction in NSC34 motor neuron-like cells. BBR (0.1-10 nM) led to increasing insulin receptor expression, Akt phosphorylation and enhanced oxidant-sensitive Nrf2/HO-1 induction, which were blocked by a PI3K inhibitor, LY294002. In H(2)O(2)-treated cells, BBR significantly attenuated ROS production and increased cell viability, antioxidant defense (GSH and SOD) and oxidant-sensitive proteins (HO-1 and Nrf2), which also were blocked by LY294002. Furthermore, BBR improved mitochondrial function by increasing mitochondrial membrane potential and decreasing the oxygen consumption rate. BBR-induced anti-apoptotic function was demonstrated by increasing anti-apoptotic protein Bcl-2 and survival of motor neuron protein (SMN) and by decreasing apoptotic proteins (cytochrome c, Bax and caspase). These results suggest that BBR, which is active at nanomolar concentration, is a potential neuroprotective agent via PI3K/Akt-dependent cytoprotective and antioxidant pathways.

Systemic gene delivery in large species for targeting spinal cord, brain, and peripheral tissues for pediatric disorders

Adeno-associated virus type 9 (AAV9) is a powerful tool for delivering genes throughout the central nervous system (CNS) following intravenous injection. Preclinical results in pediatric models of spinal muscular atrophy (SMA) and lysosomal storage disorders provide a compelling case for advancing AAV9 to the clinic. An important translational step is to demonstrate efficient CNS targeting in large animals at various ages. In the present study, we tested systemically injected AAV9 in cynomolgus macaques, administered at birth through 3 years of age for targeting CNS and peripheral tissues. We show that AAV9 was efficient at crossing the blood–brain barrier (BBB) at all time points investigated. Transgene expression was detected primarily in glial cells throughout the brain, dorsal root ganglia neurons and motor neurons within the spinal cord, providing confidence for translation to SMA patients. Systemic injection also efficiently targeted skeletal muscle and peripheral organs. To specifically target the CNS, we explored AAV9 delivery to cerebrospinal fluid (CSF). CSF injection efficiently targeted motor neurons, and restricted gene expression to the CNS, providing an alternate delivery route and potentially lower manufacturing requirements for older, larger patients. Our findings support the use of AAV9 for gene transfer to the CNS for disorders in pediatric populations.