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1.
Biochem Soc Trans ; 52(3): 1293-1304, 2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38716884

ABSTRACT

ATP has recently been reconsidered as a molecule with functional properties which go beyond its recognized role of the energetic driver of the cell. ATP has been described as an allosteric modulator as well as a biological hydrotrope with anti-aggregation properties in the crowded cellular environment. The role of ATP as a modulator of the homeostasis of the neurotrophins (NTs), a growth factor protein family whose most known member is the nerve growth factor (NGF), has been investigated. The modulation of NTs by small endogenous ligands is still a scarcely described area, with few papers reporting on the topic, and very few reports on the molecular determinants of these interactions. However, a detailed atomistic description of the NTs interaction landscape is of urgent need, aiming at the identification of novel molecules as potential therapeutics and considering the wide range of potential pharmacological applications for NGF and its family members. This mini-review will focus on the unique cartography casting the interactions of the endogenous ligand ATP, in the interaction with NGF as well as with its precursor proNGF. These interactions revealed interesting features of the ATP binding and distinct differences in the binding mode between the highly structured mature NGF and its precursor, proNGF, which is characterized by an intrinsically unstructured domain. The overview on the recent available data will be presented, together with the future perspectives on the field.


Subject(s)
Adenosine Triphosphate , Nerve Growth Factor , Protein Binding , Nerve Growth Factor/metabolism , Adenosine Triphosphate/metabolism , Humans , Animals , Protein Precursors/metabolism , Nerve Growth Factors/metabolism , Nerve Growth Factors/chemistry , Ligands , Binding Sites
2.
Exp Eye Res ; 238: 109743, 2024 01.
Article in English | MEDLINE | ID: mdl-38056550

ABSTRACT

Pigment epithelium-derived factor (PEDF) is widely recognized as a neuroprotective factor expressed in the retina and has shown therapeutic potential in several retinal diseases. Our study aimed to identify the neuroprotective fragment in PEDF and investigate its protective activity in retinas under ischemia-reperfusion (IR) condition. We synthesized a series of shorter synthetic peptides, 6-mer (Ser93-Gln98) and its d-form variant (6 dS) derived from the 44-mer (Val78-Thr121; a PEDF neurotrophic fragment), to determine their cytoprotective activity in IR injury, which was induced in rat retinas by injection of saline into the anterior chamber to increase the intraocular pressure (IOP) followed by reperfusion. We found the cytoprotective effect of 6-mer on glutamate-treated Neuro-2a cells and tert-butyl hydroperoxide (tBHP)-treated 661W cells were 2.6-fold and 1.5-fold higher than the 44-mer, respectively. The cytoprotective effect was blocked by a chemical inhibitor atglistatin and blocking antibody targeting PEDF receptor (PEDF-R). IR induced several impairments in retina, including cell apoptosis, activation of microglia/macroglia, degeneration of retinal capillaries, reduction in electroretinography (ERG) amplitudes, and retinal atrophy. Such IR injuries were ameliorated by treatment with 6-mer and 6 dS eye drops. Also, the neuroprotective activity of 6-mer and 6 dS in ischemic retinas were dramatically reversed by atglistatin preconditioning. Taken together, our data demonstrate smallest neuroprotective fragment of PEDF has potential to treat retinal degeneration-related diseases.


Subject(s)
Eye Proteins , Nerve Growth Factors , Reperfusion Injury , Retina , Retinitis , Serpins , Animals , Rats , Rabbits , Nerve Growth Factors/administration & dosage , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Eye Proteins/administration & dosage , Eye Proteins/chemistry , Eye Proteins/metabolism , Serpins/administration & dosage , Serpins/chemistry , Serpins/metabolism , Retina/metabolism , Retina/pathology , Reperfusion Injury/metabolism , Cytoprotection , Apoptosis , Neurons/metabolism , Retinitis/drug therapy , Retinitis/metabolism , Administration, Topical , Peptides/administration & dosage , Peptides/metabolism
3.
Nature ; 618(7967): 1065-1071, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37198476

ABSTRACT

Eukaryotic cells can undergo different forms of programmed cell death, many of which culminate in plasma membrane rupture as the defining terminal event1-7. Plasma membrane rupture was long thought to be driven by osmotic pressure, but it has recently been shown to be in many cases an active process, mediated by the protein ninjurin-18 (NINJ1). Here we resolve the structure of NINJ1 and the mechanism by which it ruptures membranes. Super-resolution microscopy reveals that NINJ1 clusters into structurally diverse assemblies in the membranes of dying cells, in particular large, filamentous assemblies with branched morphology. A cryo-electron microscopy structure of NINJ1 filaments shows a tightly packed fence-like array of transmembrane α-helices. Filament directionality and stability is defined by two amphipathic α-helices that interlink adjacent filament subunits. The NINJ1 filament features a hydrophilic side and a hydrophobic side, and molecular dynamics simulations show that it can stably cap membrane edges. The function of the resulting supramolecular arrangement was validated by site-directed mutagenesis. Our data thus suggest that, during lytic cell death, the extracellular α-helices of NINJ1 insert into the plasma membrane to polymerize NINJ1 monomers into amphipathic filaments that rupture the plasma membrane. The membrane protein NINJ1 is therefore an interactive component of the eukaryotic cell membrane that functions as an in-built breaking point in response to activation of cell death.


Subject(s)
Cell Adhesion Molecules, Neuronal , Cell Death , Cell Membrane , Nerve Growth Factors , Animals , Humans , Mice , Cell Adhesion Molecules, Neuronal/chemistry , Cell Adhesion Molecules, Neuronal/genetics , Cell Adhesion Molecules, Neuronal/metabolism , Cell Adhesion Molecules, Neuronal/ultrastructure , Cell Membrane/metabolism , Cell Membrane/pathology , Cell Membrane/ultrastructure , Cryoelectron Microscopy , Nerve Growth Factors/chemistry , Nerve Growth Factors/genetics , Nerve Growth Factors/metabolism , Nerve Growth Factors/ultrastructure , Mutagenesis, Site-Directed , Biopolymers/chemistry , Biopolymers/genetics , Biopolymers/metabolism
4.
Ageing Res Rev ; 82: 101763, 2022 12.
Article in English | MEDLINE | ID: mdl-36272696

ABSTRACT

Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a novel evolutionarily conserved protein present in both vertebrate and invertebrate species. MANF shows distinct structural and functional properties than the traditional neurotrophic factors (NTF). MANF is composed of an N-terminal saposin-like lipid-binding domain and a C-terminal SAF-A/B, Acinus and PIAS (SAP) domain connected by a short linker. The two well-described activities of MANF include (1) role as a neurotrophic factor that plays direct neuroprotective effects in the nervous system and (2) cell protective effects in the animal models of non-neuronal diseases, including retinal damage, diabetes mellitus, liver injury, myocardial infarction, nephrotic syndrome, etc. The main objective of the current review is to provide up-to-date insights regarding the structure of MANF, mechanisms regulating its expression and secretion, physiological functions in various tissues and organs, protective effects during aging, and potential clinical applications. Together, this review highlights the importance of MANF in reversing age-related dysfunction and geroprotection.


Subject(s)
Astrocytes , Neuroprotective Agents , Animals , Humans , Astrocytes/metabolism , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Nerve Growth Factors/therapeutic use , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Endoplasmic Reticulum Stress
5.
J Biol Chem ; 298(9): 102272, 2022 09.
Article in English | MEDLINE | ID: mdl-35850303

ABSTRACT

The axon initial segment (AIS) has characteristically dense clustering of voltage-gated sodium channels (Nav), cell adhesion molecule Neurofascin 186 (Nfasc), and neuronal scaffold protein Ankyrin-G (AnkG) in neurons, which facilitates generation of an action potential and maintenance of axonal polarity. However, the mechanisms underlying AIS assembly, maintenance, and plasticity remain poorly understood. Here, we report the high-resolution crystal structure of the AnkG ankyrin repeat (ANK repeat) domain in complex with its binding site in the Nfasc cytoplasmic tail that shows, in conjunction with binding affinity assays with serial truncation variants, the molecular basis of AnkG-Nfasc binding. We confirm AnkG interacts with the FIGQY motif in Nfasc, and we identify another region required for their high affinity binding. Our structural analysis revealed that ANK repeats form 4 hydrophobic or hydrophilic layers in the AnkG inner groove that coordinate interactions with essential Nfasc residues, including F1202, E1204, and Y1212. Moreover, we show disruption of the AnkG-Nfasc complex abolishes Nfasc enrichment at the AIS in cultured mouse hippocampal neurons. Finally, our structural and biochemical analysis indicated that L1 syndrome-associated mutations in L1CAM, a member of the L1 immunoglobulin family proteins including Nfasc, L1CAM, NrCAM, and CHL1, compromise binding with ankyrins. Taken together, these results define the mechanisms underlying AnkG-Nfasc complex formation and show that AnkG-dependent clustering of Nfasc is required for AIS integrity.


Subject(s)
Ankyrin Repeat , Ankyrins , Axon Initial Segment , Cell Adhesion Molecules , Nerve Growth Factors , Animals , Ankyrins/chemistry , Axon Initial Segment/chemistry , Binding Sites , Cell Adhesion Molecules/chemistry , Cell Adhesion Molecules/genetics , Crystallography, X-Ray , Mice , Nerve Growth Factors/chemistry , Nerve Growth Factors/genetics , Neural Cell Adhesion Molecule L1/genetics , Neural Cell Adhesion Molecule L1/metabolism , Protein Domains
6.
Yakugaku Zasshi ; 142(3): 241-277, 2022.
Article in Japanese | MEDLINE | ID: mdl-35228379

ABSTRACT

Neurotrophic factors have been shown to potentially be beneficial for the treatment of neurodegenerative diseases such as Alzheimer's disease, because endogenous neurotrophic factors (NGF, BDNF) have been recognized to play critical roles in the promotion of neurogenesis, differentiation, and neuroprotection throughout the development of the central nervous system. However, high-molecular-weight proteins are unable to cross the blood-brain barrier and are easily decomposed under physiological conditions. Thus, small molecules that can mimic the functions of neurotrophic factors are promising alternatives for the treatment of neurodegenerative disease. Since 1990, the author has been involved in searching for natural products with typical neurotrophic properties that can cause neurogenesis, enhance neurite outgrowth, and protect against neuronal death by using three cellular systems (PC12, rat cortical neurons, and MEB5 cells). Through these research activities on neurotrophic natural products, the author has tried to induce a paradigm shift from the discipline of natural products chemistry to science disciplines. This review focuses on our independent synthetic studies of the neurotrophic natural products discovered in the plants. The following synthetic elaborations are described: syntheses of dimeric isocuparane-type sesquiterpenes mastigophorenes A and B, macrocyclic bis-bibenzyls plagiochins A-D and cavicularin through a Pd-catalyzed Stille-Kelly reaction; the formal synthesis of merrilactone A and jiadifenin, which are seco-prezizaane-type sesquiterpenes, through intramolecular Pd-catalyzed Mizoroki-Heck and Tsuji-Trost reactions; and finally the first enantioselective synthesis of neovibsanin B, a vibsane-type diterpene, through a Pd-catalyzed cyclic carbopalladation-carbonyl tandem reaction.


Subject(s)
Biological Products/chemical synthesis , Nerve Growth Factors/chemical synthesis , Animals , Biological Products/chemistry , Biological Products/pharmacology , Biological Products/therapeutic use , Blood-Brain Barrier/metabolism , Bridged-Ring Compounds/chemical synthesis , Cyclopentanes/chemical synthesis , Diterpenes/chemical synthesis , Lactones/chemical synthesis , Mice , Molecular Weight , Nerve Growth Factors/chemistry , Nerve Growth Factors/pharmacology , Nerve Growth Factors/therapeutic use , Neurodegenerative Diseases/drug therapy , Organic Chemistry Phenomena , Rats , Sesquiterpenes/chemical synthesis , Stereoisomerism
7.
Bioorg Med Chem Lett ; 60: 128580, 2022 03 15.
Article in English | MEDLINE | ID: mdl-35066142

ABSTRACT

Majucin-type Illicium sesquiterpenes with potent neurotrophic activity are considered to be promising candidates for the treatment of various neurodegenerative disease. Owing to the low-abundance metabolites in Illicium genus, there are few studies on their structural modifications, structure-activity relationships, and pharmacophoric motif. Herein, structural modifications were conducted on the hydroxyl groups at C-3 and C-6 positions of two majucin-type compounds neomajucin (1) and majucin (2), and 39 neomajucin/majucin based esters were synthesized and evaluated for their neurite outgrowth-promoting activities. Among all the target derivatives, compounds 1a, 1j, 1r, 2b, 2d, 3a, 3b, 3d and 3h displayed more potent neurite outgrowth-promoting activity than their precursors. Some interesting structure-activity relationships (SARs) were also observed. Moreover, compound 1a showed good neuroprotective effect on MPP+-induced PC12 cell damage. Finally, compounds 1a and 3a exhibited relatively no cytotoxicity to normal human H9C2 cardiac cells. This work will shed light on the development of neomajucin/majucin derivatives as potential neurotrophic agents.


Subject(s)
Nerve Growth Factors/pharmacology , Neurodegenerative Diseases/drug therapy , Neuronal Outgrowth/drug effects , Neuroprotective Agents/pharmacology , Small Molecule Libraries/pharmacology , Animals , Cell Differentiation/drug effects , Cell Line , Dose-Response Relationship, Drug , Humans , Illicium/chemistry , Molecular Structure , Nerve Growth Factors/chemical synthesis , Nerve Growth Factors/chemistry , Neurodegenerative Diseases/metabolism , Neuroprotective Agents/chemical synthesis , Neuroprotective Agents/chemistry , PC12 Cells , Rats , Small Molecule Libraries/chemical synthesis , Small Molecule Libraries/chemistry , Structure-Activity Relationship
8.
Mol Ther ; 29(9): 2821-2840, 2021 09 01.
Article in English | MEDLINE | ID: mdl-33940158

ABSTRACT

A molecular hallmark in Parkinson's disease (PD) pathogenesis are α-synuclein aggregates. Cerebral dopamine neurotrophic factor (CDNF) is an atypical growth factor that is mostly resident in the endoplasmic reticulum but exerts its effects both intracellularly and extracellularly. One of the beneficial effects of CDNF can be protecting neurons from the toxic effects of α-synuclein. Here, we investigated the effects of CDNF on α-synuclein aggregation in vitro and in vivo. We found that CDNF directly interacts with α-synuclein with a KD = 23 ± 6 nM and reduces its auto-association. Using nuclear magnetic resonance (NMR) spectroscopy, we identified interaction sites on the CDNF protein. Remarkably, CDNF reduces the neuronal internalization of α-synuclein fibrils and induces the formation of insoluble phosphorylated α-synuclein inclusions. Intra-striatal CDNF administration alleviates motor deficits in rodents challenged with α-synuclein fibrils, though it did not reduce the number of phosphorylated α-synuclein inclusions in the substantia nigra. CDNF's beneficial effects on rodent behavior appear not to be related to the number of inclusions formed in the current context, and further study of its effects on the aggregation mechanism in vivo are needed. Nonetheless, the interaction of CDNF with α-synuclein, modifying its aggregation, spreading, and associated behavioral alterations, provides novel insights into the potential of CDNF as a therapeutic strategy in PD and other synucleinopathies.


Subject(s)
Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Parkinson Disease/physiopathology , Substantia Nigra/metabolism , alpha-Synuclein/chemistry , alpha-Synuclein/metabolism , Animals , Binding Sites , Cell Line , Disease Models, Animal , Dopamine/metabolism , Humans , Magnetic Resonance Spectroscopy , Male , Mice , Models, Molecular , Parkinson Disease/metabolism , Phosphorylation , Primary Cell Culture , Protein Aggregates , Protein Binding , Protein Conformation , Rats
9.
Proc Natl Acad Sci U S A ; 118(18)2021 05 04.
Article in English | MEDLINE | ID: mdl-33903230

ABSTRACT

Neuropeptides and neurotrophic factors secreted from dense core vesicles (DCVs) control many brain functions, but the calcium sensors that trigger their secretion remain unknown. Here, we show that in mouse hippocampal neurons, DCV fusion is strongly and equally reduced in synaptotagmin-1 (Syt1)- or Syt7-deficient neurons, but combined Syt1/Syt7 deficiency did not reduce fusion further. Cross-rescue, expression of Syt1 in Syt7-deficient neurons, or vice versa, completely restored fusion. Hence, both sensors are rate limiting, operating in a single pathway. Overexpression of either sensor in wild-type neurons confirmed this and increased fusion. Syt1 traveled with DCVs and was present on fusing DCVs, but Syt7 supported fusion largely from other locations. Finally, the duration of single DCV fusion events was reduced in Syt1-deficient but not Syt7-deficient neurons. In conclusion, two functionally redundant calcium sensors drive neuromodulator secretion in an expression-dependent manner. In addition, Syt1 has a unique role in regulating fusion pore duration.


Subject(s)
Brain/metabolism , Neurons/metabolism , Neurotransmitter Agents/chemistry , Synaptotagmin I/genetics , Synaptotagmins/genetics , Animals , Calcium/chemistry , Calcium/metabolism , Dense Core Vesicles/genetics , Dense Core Vesicles/metabolism , Gene Expression Regulation/genetics , Hippocampus/metabolism , Humans , Mice , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Neurons/pathology , Neuropeptides/chemistry , Neuropeptides/metabolism , Neurotransmitter Agents/metabolism
10.
Nature ; 591(7848): 131-136, 2021 03.
Article in English | MEDLINE | ID: mdl-33472215

ABSTRACT

Plasma membrane rupture (PMR) is the final cataclysmic event in lytic cell death. PMR releases intracellular molecules known as damage-associated molecular patterns (DAMPs) that propagate the inflammatory response1-3. The underlying mechanism of PMR, however, is unknown. Here we show that the cell-surface NINJ1 protein4-8, which contains two transmembrane regions, has an essential role in the induction of PMR. A forward-genetic screen of randomly mutagenized mice linked NINJ1 to PMR. Ninj1-/- macrophages exhibited impaired PMR in response to diverse inducers of pyroptotic, necrotic and apoptotic cell death, and were unable to release numerous intracellular proteins including HMGB1 (a known DAMP) and LDH (a standard measure of PMR). Ninj1-/- macrophages died, but with a distinctive and persistent ballooned morphology, attributable to defective disintegration of bubble-like herniations. Ninj1-/- mice were more susceptible than wild-type mice to infection with Citrobacter rodentium, which suggests a role for PMR in anti-bacterial host defence. Mechanistically, NINJ1 used an evolutionarily conserved extracellular domain for oligomerization and subsequent PMR. The discovery of NINJ1 as a mediator of PMR overturns the long-held idea that cell death-related PMR is a passive event.


Subject(s)
Cell Adhesion Molecules, Neuronal/metabolism , Cell Death , Cell Membrane/metabolism , Nerve Growth Factors/metabolism , Animals , Apoptosis , Cell Adhesion Molecules, Neuronal/chemistry , Cell Adhesion Molecules, Neuronal/genetics , Cell Death/genetics , Female , Humans , Macrophages , Male , Mice , Mutation , Necrosis , Nerve Growth Factors/chemistry , Nerve Growth Factors/genetics , Protein Multimerization , Pyroptosis/genetics
11.
Drug Des Devel Ther ; 14: 5393-5403, 2020.
Article in English | MEDLINE | ID: mdl-33304094

ABSTRACT

INTRODUCTION: Carbamoylated erythropoietin (CEPO) is a chemically engineered, nonhematopoietic derivative of erythropoietin (EPO) that retains its antidepressant and pro-cognitive effects, which are attributed to the increased expression of neurotrophic factors like brain derived neurotrophic factor (BDNF), in the central nervous system. However, the chemical modification process which produces CEPO from erythropoietin (EPO) requires pure EPO as raw material, is challenging to scale-up and can also cause batch-to-batch variability. To address these key limitations while retaining its behavioral effects, we designed, expressed and analyzed a triple, glutamine, substitution recombinant mimetic of CEPO, named QPO. METHODS AND MATERIALS: We employ a combination of computational structural biology, molecular, cellular and behavioral assays to design, produce, purify and test QPO. RESULTS: QPO was shown to be a nonhematopoietic polypeptide with significant antidepressant-like and pro-cognitive behavioral effects in rodent assays while significantly upregulating BDNF expression in-vitro and in-vivo. The in-silico binding affinity analysis of QPO bound to the EPOR/EPOR homodimer receptor shows significantly decreased binding to Active Site 2, but not Active Site 1, of EPOR. DISCUSSION: The results of the behavioral and gene expression analysis imply that QPO is a successful CEPO mimetic protein and potentially acts via a similar neurotrophic mechanism, making it a drug development target for psychiatric disorders. The decreased binding to Active Site 2 could imply that this active site is not involved in neuroactive signaling and could allow the development of a functional innate repair receptor (IRR) model. Substituting the three glutamine substitution residues with arginine (RPO) resulted in the loss of behavioral activity, indicating the importance of glutamine residues at those positions.


Subject(s)
Antidepressive Agents/therapeutic use , Drug Development , Mental Disorders/drug therapy , Nerve Growth Factors/therapeutic use , Animals , Antidepressive Agents/chemistry , Antidepressive Agents/isolation & purification , Cell Line, Tumor , Male , Mice , Mice, Inbred BALB C , Nerve Growth Factors/chemistry , Nerve Growth Factors/isolation & purification , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism
12.
Org Lett ; 22(19): 7676-7680, 2020 10 02.
Article in English | MEDLINE | ID: mdl-32955264

ABSTRACT

Meloyunnanines A-C, three alkaloids with an unprecedented skeleton, were isolated from fruits of Melodinus yunnanensis. The structures featuring a caged-6/6/5/6/5/5 ring system were elucidated by the analysis of comprehensive spectroscopic and X-ray data. Biosynthetically, meloyunnanines A-C were assigned to monoterpenoid quinoline alkaloids (MQAs), derived from monoterpenoid indole alkaloids through oxidation and rearrangement. These compounds together with three known Melodinus MQAs were evaluated for their neurotrophic activity and scandine N4-oxide exhibited significant effect.


Subject(s)
Apocynaceae/chemistry , Monoterpenes/pharmacology , Nerve Growth Factors/pharmacology , Secologanin Tryptamine Alkaloids/pharmacology , Drug Screening Assays, Antitumor , Fruit , Humans , Molecular Structure , Monoterpenes/chemistry , Monoterpenes/isolation & purification , Nerve Growth Factors/chemistry , Neurites , Quinolines/chemistry , Secologanin Tryptamine Alkaloids/chemistry , Secologanin Tryptamine Alkaloids/isolation & purification
13.
Proc Natl Acad Sci U S A ; 117(21): 11450-11458, 2020 05 26.
Article in English | MEDLINE | ID: mdl-32385162

ABSTRACT

Dynamic remodeling of the extracellular matrix affects many cellular processes, either directly or indirectly, through the regulation of soluble ligands; however, the mechanistic details of this process remain largely unknown. Here we propose that type I collagen remodeling regulates the receptor-binding activity of pigment epithelium-derived factor (PEDF), a widely expressed secreted glycoprotein that has multiple important biological functions in tissue and organ homeostasis. We determined the crystal structure of PEDF in complex with a disulfide cross-linked heterotrimeric collagen peptide, in which the α(I) chain segments-each containing the respective PEDF-binding region (residues 930 to 938)-are assembled with an α2α1α1 staggered configuration. The complex structure revealed that PEDF specifically interacts with a unique amphiphilic sequence, KGHRGFSGL, of the type I collagen α1 chain, with its proposed receptor-binding sites buried extensively. Molecular docking demonstrated that the PEDF-binding surface of type I collagen contains the cross-link-susceptible Lys930 residue of the α1 chain and provides a good foothold for stable docking with the α1(I) N-telopeptide of an adjacent triple helix in the fibril. Therefore, the binding surface is completely inaccessible if intermolecular crosslinking between two crosslink-susceptible lysyl residues, Lys9 in the N-telopeptide and Lys930, is present. These structural analyses demonstrate that PEDF molecules, once sequestered around newly synthesized pericellular collagen fibrils, are gradually liberated as collagen crosslinking increases, making them accessible for interaction with their target cell surface receptors in a spatiotemporally regulated manner.


Subject(s)
Collagen Type I/metabolism , Eye Proteins/chemistry , Eye Proteins/metabolism , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Serpins/chemistry , Serpins/metabolism , Binding Sites , Circular Dichroism , Collagen Type I/chemistry , Crystallography, X-Ray , Disulfides/chemistry , Lysine/chemistry , Molecular Docking Simulation , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Conformation , Signal Transduction , Spatio-Temporal Analysis
14.
J Mol Neurosci ; 70(8): 1293-1302, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32458204

ABSTRACT

TLQP62 is a neuropeptide derived from the neurotrophin-inducible VGF (non-acronymic) protein with antidepressant-like properties capable of inducing increased memory on the mouse hippocampus by promoting neurogenesis and synaptic plasticity through brain-derived neurotropic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB). Human SH-SY5Y neuroblastoma-derived cell line is widely used in neuroscience research and is known to undergo neurodifferentiation in the presence of all-trans retinoic acid by upregulating the expression of TrkB, making cells responsive to BDNF. As TLQP62 promotes BDNF expression, which in turn activates a BDNF/TrkB/CREB (cAMP response element-binding protein) pathway that upregulates VGF expression, there is a VGF-BDNF regulatory loop that seems to regulate neurogenesis. Therefore, here, we evaluate by morphological observation the ability of human TLQP62 to induce neuritogenesis of human SH-SY5Y neuroblastoma-derived cell line in a retinoic acid and BDFN-like way, making this cell line a suitable cell model for further studies concerning TLQP62 molecular mechanisms and signalling pathways. SIGNIFICANCE STATEMENT: VGF has been widely explored for its role in emotional behaviour and neuropsychiatric illness (Bartolomucci et al. 2011). Although VGF levels were found reduced in leukocytes of depressed patients, after antidepressant treatment or voluntary exercise, those levels were found to be restored in the hippocampus (Hunsberger et al. 2007; Thakker-Varia et al. 2007). Administration to hippocampal cells of TLQP62 produced an increase in synaptic charge that could explain this antidepressants effects (Alder et al. 2003). This interesting role of TLQP62 in the brain, especially in the hippocampus, makes this neuropeptide an attractive target for further investigation of its role in neurogenesis, learning, memory, and neurological disorders, and possible treatment development. Thus, the identification of a receptor(s) for this peptide and associated signalling pathway(s) is of high importance, as well as a proper cell model to perform those studies.


Subject(s)
Neuronal Outgrowth/drug effects , Peptides/pharmacology , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Cell Line, Tumor , Cyclic AMP Response Element-Binding Protein/metabolism , Humans , Membrane Glycoproteins/metabolism , Nerve Growth Factors/chemistry , Peptides/chemistry , Receptor, trkB/metabolism , Signal Transduction
15.
J Mol Biol ; 432(13): 3749-3760, 2020 06 12.
Article in English | MEDLINE | ID: mdl-32302608

ABSTRACT

Optically controlled receptor tyrosine kinases (opto-RTKs) allow regulation of RTK signaling using light. Until recently, the majority of opto-RTKs were activated with blue-green light. Fusing a photosensory core module of Deinococcus radiodurans bacterial phytochrome (DrBphP-PCM) to the kinase domains of neurotrophin receptors resulted in opto-RTKs controlled with light above 650 nm. To expand this engineering approach to RTKs of other families, here we combined the DrBpP-PCM with the cytoplasmic domains of EGFR and FGFR1. The resultant Dr-EGFR and Dr-FGFR1 opto-RTKs are rapidly activated with near-infrared and inactivated with far-red light. The opto-RTKs efficiently trigger ERK1/2, PI3K/Akt, and PLCγ signaling. Absence of spectral crosstalk between the opto-RTKs and green fluorescent protein-based biosensors enables simultaneous Dr-FGFR1 activation and detection of calcium transients. Action mechanism of the DrBphP-PCM-based opto-RTKs is considered using the available RTK structures. DrBphP-PCM represents a versatile scaffold for engineering of opto-RTKs that are reversibly regulated with far-red and near-infrared light.


Subject(s)
Phytochrome/ultrastructure , Receptor Protein-Tyrosine Kinases/ultrastructure , Tissue Engineering/methods , Tissue Scaffolds/chemistry , Biosensing Techniques , Deinococcus/chemistry , Deinococcus/genetics , Green Fluorescent Proteins/chemistry , HeLa Cells , Humans , Light , MAP Kinase Signaling System/radiation effects , Nerve Growth Factors/chemistry , Nerve Growth Factors/genetics , Phosphatidylinositol 3-Kinases/genetics , Phytochrome/chemistry , Phytochrome/genetics , Protein Conformation/radiation effects , Proto-Oncogene Proteins c-akt/genetics , Receptor Protein-Tyrosine Kinases/chemistry , Receptor Protein-Tyrosine Kinases/genetics , Receptor, Fibroblast Growth Factor, Type 1/chemistry , Receptor, Fibroblast Growth Factor, Type 1/genetics , Receptors, Nerve Growth Factor/chemistry , Receptors, Nerve Growth Factor/genetics , Signal Transduction/radiation effects
17.
ACS Appl Mater Interfaces ; 12(14): 16168-16177, 2020 Apr 08.
Article in English | MEDLINE | ID: mdl-32182427

ABSTRACT

Peripheral nerve injury (PNI) was the leading cause of permanent dysfunction in movement and sensation. Synthesized nerve guide conduits (NGCs) with Schwann Cells (SCs) can help peripheral nerve regeneration. However, poor accessibility of SCs and lack of full coverage of seeded cells on NGCs can lead to failure of nerve regeneration across long gaps and full functional recovery. To overcome these limitations, bone marrow stromal cells (BMSCs) and a novel culture method were proposed in the current study. BMSCs were harvested and seeded on a never growth factor (NGF)-loaded PCL nanofibrous NGCs and cultured with a rotary cell culture system (RCCS) before implantation. The NGCs were tested in vitro with PC-12 cells to validate the bioactivity of released NGF and to access its ability to promote neurite extension. Also, the NGCs were tested in vivo with rat sciatic nerve model to exam its potential in bridging the long gap (15 mm segmental defect). The efficacy of the NGCs was investigated based on the results of the functional test, electrophysiology test, muscle atrophy, and histological analysis. The results of in vitro PC-12 cell study confirmed the bioactivity of released NGF and showed a significant increase in the neurite extension with the help of PEG-diamine and BSA. These results showed that the novel loading method could preserve the bioactivity of growth factors and achieve a sustained release in vitro. Besides, the results of the in vivo study exhibited a significant increase with the combination of all additives. These results showed that with the help of NGF and RCCS, the NGCs with the seeded BMSCs could enhance peripheral nerve regeneration across long nerve injury gaps.


Subject(s)
Nanofibers/chemistry , Nerve Regeneration/drug effects , Peripheral Nerve Injuries/therapy , Sciatic Nerve/drug effects , Animals , Bioreactors , Cell Culture Techniques , Disease Models, Animal , Humans , Mesenchymal Stem Cells/drug effects , Nanofibers/therapeutic use , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , PC12 Cells , Peripheral Nerve Injuries/pathology , Peripheral Nerves/drug effects , Peripheral Nerves/growth & development , Peripheral Nerves/pathology , Rats , Schwann Cells/drug effects , Sciatic Nerve/growth & development , Sciatic Nerve/pathology
18.
Biomed Mater ; 15(3): 035020, 2020 04 29.
Article in English | MEDLINE | ID: mdl-32079004

ABSTRACT

Spinal cord injury is a devastating trauma with high mortality and disability, for which there is no effective treatment. Stem cell-based tissue engineering has been reported to promote functional neural recovery. At present, building a neural scaffold with excellent biocompatibility for cells and tissues is still challenging. In this study, a new thermosensitive composite hydrogel based on chitosan, hydroxyethyl cellulose, collagen and ß-phosphoglycerate (CS-HEC-Col/GP hydrogel) is developed to encapsulate murine bone marrow-derived mesenchymal stem cells (BMSCs) to improve therapeutic efficacy in spinal cord injured mice. This composite hydrogel possesses a good cytocompatibility to mouse BMSCs by live/dead staining, minimized inflammatory reaction in vivo by hematoxylin and eosin staining and suitable rheological behavior similar to neural tissue, ranging from 100 to 1000 Pa. Furthermore, the data from animal experiments indicated that BMSC-loaded CS-HEC-Col/GP hydrogel could enhance the survival or proliferation of endogenous nerve cells, probably by secreting neurotrophic factors and inhibiting apoptosis, and thereby promote the recovery of motor function in the hindlimbs of a murine spinal cord injury model.


Subject(s)
Bone Marrow Cells/cytology , Chitosan/chemistry , Hydrogels/chemistry , Mesenchymal Stem Cells/cytology , Spinal Cord Injuries/metabolism , Tissue Engineering/methods , Animals , Apoptosis , Biocompatible Materials , Body Temperature , Cellulose/analogs & derivatives , Cellulose/chemistry , Culture Media , Male , Mice , Mice, Inbred C57BL , Motor Skills , Nerve Growth Factors/chemistry , Neurons/metabolism , Pressure , Rheology/methods , Spinal Cord Injuries/therapy
19.
Mol Neurobiol ; 57(4): 1799-1813, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31838721

ABSTRACT

Neuregulin 2 (NRG2) belongs to the EGF family of growth factors. Most of this family members require proteolytic cleavage to liberate their ectodomains capable of binding and activating their cognate ErbB receptors. To date, most of the studies investigating proteolytic processing of neuregulins focused on NRG1, which was shown to undergo ectodomain shedding by several ADAM proteases and BACE1 and the remaining fragment was further cleaved by γ-secretase. Recently, NRG2 attracted more attention due to its role in the neurogenesis and modulation of behaviors associated with psychiatric disorders. In this study, we used genetic engineering methods to identify proteases involved in proteolytic processing of murine NRG2. Using non-neuronal cell lines as well as cultures of primary hippocampal neurons, we demonstrated that the major proteases responsible for releasing NRG2 ectodomain are ADAM10 and BACE2. Co-expression of NRG2 and BACE2 in neurons of certain brain structures including medulla oblongata and cerebellar deep nuclei was confirmed via immunohistochemical staining. The cleavage of NRG2 by ADAM10 or BACE2 generates a C-terminal fragment that serves as a substrate for γ-secretase. We also showed that murine NRG2 is subject to post-translational modifications, substantial glycosylation of its extracellular part, and phosphorylation of the cytoplasmic tail.


Subject(s)
Nerve Growth Factors/metabolism , Protein Processing, Post-Translational , ADAM10 Protein/metabolism , Amyloid Precursor Protein Secretases/metabolism , Animals , Aspartic Acid Endopeptidases/metabolism , Cell Line, Tumor , Glycosylation , Mice, Inbred C57BL , Nerve Growth Factors/chemistry , Open Reading Frames/genetics , Protein Domains , Substrate Specificity
20.
Biomed Res Int ; 2019: 5320902, 2019.
Article in English | MEDLINE | ID: mdl-31886225

ABSTRACT

Pregnancy is a period in a woman's life in which changes can occur that affect different physiological processes. Common conditions during this period include vascular changes, such as lower extremity venous insufficiency (VI). This is an observational, analytical, and prospective cohort study in which 114 pregnant women were analyzed, of which 62 were clinically diagnosed with VI. In parallel, 52 control patients without VI (HC) were studied. The aim of this study was to observe changes in angiogenesis and inflammation markers as well as the presence of calcium deposits. The expression of vascular endothelial growth factor (VEGF), transforming growth factor-ß (TGF-ß), and pigment epithelium-derived factor (PEDF) was analyzed by immunohistochemistry and RT-qPCR. The presence of calcium deposits was revealed using the von Kossa method. In the placentas of mothers with VI, gene expression of VEGF (34.575 [32.380-36.720] VI vs 32.965 [30.580-36.320] HC) and PEDF (25.417 [24.459-27.675] VI vs 24.400 [23.102-30.223] HC) significantly increased, as was protein expression in the placental villi. An increase in calcium deposits was observed in the placentas of women with VI (72.58% VI/53.84% HC). This study revealed the existence of cellular damage in the placental villi of mothers with VI with tissue implications such as increased calcification.


Subject(s)
Calcinosis/metabolism , Eye Proteins/analysis , Nerve Growth Factors/analysis , Placenta , Pregnancy Complications, Cardiovascular/metabolism , Serpins/analysis , Vascular Endothelial Growth Factor A/analysis , Venous Insufficiency/metabolism , Adolescent , Adult , Calcinosis/physiopathology , Eye Proteins/chemistry , Eye Proteins/metabolism , Female , Humans , Lower Extremity/physiopathology , Nerve Growth Factors/chemistry , Nerve Growth Factors/metabolism , Placenta/blood supply , Placenta/chemistry , Placenta/pathology , Pregnancy , Pregnancy Complications, Cardiovascular/physiopathology , Prospective Studies , Serpins/chemistry , Serpins/metabolism , Up-Regulation , Vascular Endothelial Growth Factor A/chemistry , Vascular Endothelial Growth Factor A/metabolism , Venous Insufficiency/physiopathology , Young Adult
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