Nerve Growth Factor Synthesis Research Articles

Nerve Growth Factor (NGF)-Receptor Survival Axis in Head and Neck Squamous Cell Carcinoma.

Neurotrophins and their receptors might regulate cell survival in head and neck squamous cell carcinoma (HNSCC). mRNA expression of nerve growth factor (NGF) and protein synthesis of high (NTRK1) and low affinity neurotrophin (p75 neurotrophin receptor; NTR) receptors were investigated in normal oral mucosa and in HNSCC. HNSCC cell lines were treated with mitomycin C (MMC) and cell survival was investigated. Normal and malignant epithelial cells expressed NGF mRNA. NTRK1 was upregulated in 80% of HNSCC tissue, and 50% of HNSCC samples were p75NTR positive. Interestingly, in HNSCC tissue: NTRK1 and p75NTR immunohistochemical reactions were mutually exclusive. Detroit 562 cell line contained only p75NTR, UPCI-SCC090 cells synthesized NTRK1 but not p75NTR and SCC-25 culture had p75NTR and NTRK1 in different cells. NGF (100 ng/mL) significantly improved (1.4-fold) the survival of cultured UPCI-SCC090 cells after MMC-induced cell cycle arrest, while Detroit 562 cells with high levels of p75NTR did not even get arrested by single short MMC treatment. p75NTR in HNSCC might be related with NGF-independent therapy resistance, while NTRK1 might transduce a survival signal of NGF and contribute in this way to improved tumor cell survival after cell cycle arrest.

Induction of nerve growth factor by phorbol 12-myristate 13-acetate is dependent upon the mitogen activated protein kinase pathway

Several small molecules have been identified that induce glial cells to synthesize and secrete nerve growth factor (NGF), a critical neurotrophin that supports neuronal growth and survival, and as such show promise in the development of drugs for the chemoprevention of Alzheimer's disease. To map the signal transduction cascade leading to NGF synthesis and secretion, cultured human glial cells were stimulated by phorbol 12-myristate 13-acetate (PMA), an agonist of Protein Kinase C. Changes in intracellular protein phosphorylation states were evaluated by reverse phase protein microarrays (RPPA), selectively screening over 130 protein endpoints. Of these, 55 proteins showed statistically significant changes in phosphorylation state due to cellular exposure to PMA. A critical signal transduction pathway was identified, and subsequent validation by ELISA and qPCR revealed that the signaling proteins Raf, MEK, ERK, and the signal transduction factor CREB are all essential to the upregulation of NGF gene expression by PMA. Additionally, members of the RSK family of kinases appear to be involved in glial secretion (exocytosis) of the NGF protein. Furthermore, through RPPA, the effects of PMA on apoptosis signaling events and cell proliferation were differentiated from the pathway to NGF upregulation. Overall, this study reveals potential protein targets for the rational design of Alzheimer's therapeutics.

The Changes of Nerve Growth Factor Serum Levels After External Muscle Stimulation and The Correlation with Diabetic Neuropathy Symptom in Diabetic Peripheral Neuropathy

Background: Diabetic Peripheral neuropathy (DPN) is a common complication of diabetes mellitus. Recentstudies have demonstrated the involvement of Nerve growth factor (NGF) in the occurrence of DPN. TheDiabetes Mellitus was caused reduced the number and disruption of the function of the NGF. External MuscleStimulation (EMS) might be induced the NGF synthesis. The study objective has to found the effect of EMSon the NGF.Methods: Study design was before and after treatment without control on subjects with DPN. The bloodsample was taken before and after an intervention, as well as the Diabetic Neuropathy symptom (DNSym) andscore (DNSc). The EMS treated all of the participants within three times a week for four weeks.Results: There were 35 subjects were participated. Paired t-test showed a significant increase in NGF serumlevels and decrease both DNSym and DNSc with the difference value 12.64 ± 16.09 (p=0.000), 1.23 ± 0.82(p=0.000), 1.20 ± 0.85 (p=0.000). There was a significant negative correlation between NGF serum level withthe DNS- INA (r= -0.56; p=0.001) and the DNE-INA (r= -0.48; p=0.007).Conclusion: EMS treatment can increase serum NGF level. EMS has a strong correlation with a decrease inthe value of the DNS-INA and DNE-INA.Keywords: Diabetic Peripheral neuropathy, External Muscle Stimulation, Nerve Growth Factor.

Gut-derived cholecystokinin contributes to visceral hypersensitivity via nerve growth factor-dependent neurite outgrowth.

Irritable bowel syndrome is characterized by abdominal pain and altered bowel habits and may occur following stressful events or infectious gastroenteritis such as giardiasis. Recent findings revealed a link between cholecystokinin (CCK), neurotrophin synthesis, and intestinal hyperalgesia. The aim was to investigate the role of CCK in visceral hypersensitivity using mouse models challenged with a bout of infection with Giardia lamblia or psychological stress, either alone or in combination. Abdominal pain was evaluated by visceromoter response to colorectal distension. Nerve fibers in intestinal tissues were stained using immunohistochemistry (PGP9.5). Human neuroblastoma SH-SY5Y cells incubated with bacterial-free mouse gut supernatant or recombinant CCK-8S were assessed for neurite outgrowth and nerve growth factor (NGF) production. Intestinal hypersensitivity was induced by either stress or Giardia infection, and a trend of increased pain was seen following dual stimuli. Increased CCK levels and PGP9.5 immunoreactivity were found in colonic mucosa of mice following stress and/or infection. Inhibitors to the CCK-A receptor (L-364718) or CCK-B receptor (L-365260) blocked visceral hypersensitivity caused by stress, but not when induced by giardiasis. Nerve fiber elongation and NGF synthesis were observed in SH-SY5Y cells after incubation with colonic supernatants from mice given the dual stimuli, or after treatment with CCK-8S. Increased nerve fiber length by colonic supernatant and CCK-8S was attenuated by L-365260 or neutralizing anti-NGF. This new model successfully recapitulates intestinal hypernociception induced by stress or Giardia. Colonic CCK contributes to visceral hypersensitivity caused by stress, but not by Giardia, partly via NGF-dependent neurite outgrowth.

Blocking transient receptor potential vanilloid 2 channel in astrocytes enhances astrocyte-mediated neuroprotection after oxygen-glucose deprivation and reoxygenation.

Astrocytes play important roles in homeostatic regulation in the central nervous system and are reported to influence the outcome of ischemic injury. Regulating Ca2+ signaling of astrocytes is a promising strategy for stroke therapy. Herein, we report for the first time that transient receptor potential vanilloid 2 (TRPV2), a Ca2+ -permeable channel that is important in osmotic balance regulation, expresses in rat cortical astrocytes by immunofluorescence. Moreover, oxygen-glucose deprivation and reoxygenation (OGD/R) treatment enhanced the expression. The TRPV2 is functional because Ca2+ imaging showed that activating the TRPV2 channel in cultured astrocytes increased intracellular Ca2+ level and the increment of intracellular Ca2+ level expanded when astrocytes were treated with OGD/R. Staining with 5-ethynyl-2'-deoxyuridine (EdU) revealed that while blocking the TRPV2, it promoted the proliferation of astrocytes. Additionally, blocking the TRPV2 in astrocytes increased the synthesis of nerve growth factor (NGF) mRNA and the secretion of NGF by real-time PCR and enzyme-linked immunosorbent assay respectively. We further found that the increased secretion of NGF could be reversed by c-JunN-terminalkinase (JNK) inhibitor and blocking the TRPV2 caused the phosphorylation of JNK. These indicated that blocking the TRPV2 induced NGF secretion via the mitogen-activated protein kinase (MAPK)-JNK signaling pathway. As the promoted proliferation of astrocytes and secretion of NGF were reported to have neuroprotective effects in the early stage of stroke, we concluded that targeting the TRPV2 channel in astrocytes might be a potential new therapeutic strategy in ischemic stroke.

4-Methylcatechol inhibits cell growth and testosterone production in TM3 Leydig cells by reducing mitochondrial activity.

4-Methylcatechol (4-MC) is a potential neuroprotective drug because it stimulates the synthesis of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in neurons. The present study explored the effect of 4-MC on cell growth and testosterone synthesis in the TM3 Leydig cells of mice. 4-MC did not enhance expression of both BDNF and NGF in these cells. However, this compound significantly inhibited cell proliferation and increased the number of apoptotic cells in a dose-dependent manner. The expression profile of Bax/Bcl-2 gene was altered considerably, and mitochondrial activity was significantly decreased in cells. 4-Methylcatechol also inhibited testosterone synthesis in TM3 Leydig cells. The inhibitory roles of this compound in relation to growth and testosterone synthesis in TM3 Leydig cells maybe associated with increased Bax gene expression and decreased mitochondrial activity. As a result, caspase cascade is activated.

Hyperbaric oxygen preserves neurotrophic activity of carbon monoxide-exposed astrocytes.

In astrocytes, carbon monoxide (CO) poisoning causes oxidative stress and mitochondrial dysfunction accompanied by caspase and calpain activation. Impairment in astrocyte function can be time-dependently reduced by hyperbaric (3bar) oxygen (HBO). Due to the central role of astrocytes in maintaining neuronal function by offering neurotrophic support we investigated the hypothesis that HBO therapy may exert beneficial effect on acute CO poisoning-induced impairment in intrinsic neurotrophic activity. Exposure to 3000ppm CO in air followed by 24-72h of normoxia caused a progressive decline of gene expression, synthesis and secretion of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) to different extent. 1h treatment with 100% oxygen disclosed a pressure- and time-dependent efficacy in preserving astrocytic neurotrophic support. The beneficial effect was most evident when the astrocytes were exposed to HBO 1-5h after exposure to CO. The results further support an active role of hyperbaric, not normobaric, oxygenation in reducing dysfunction of astrocytes after acute CO poisoning. By preserving endogenous neurotrophic activity HBO therapy might promote neuronal protection and thus prevent the occurrence of late neuropsychological sequelae.

Toll-like Receptor 2 Regulates Nerve Growth Factor Synthesis via NF-κB Signaling in Human Intervertebral Disc Cells

IntroductionIntervertebral disc degeneration is a leading cause of chronic low back pain (LBP), but how degeneration contributes to LBP is poorly understood. Nerve growth factor (NGF) levels increase during disc degeneration and evidence suggests NGF promotes disc innervation, neuronal sensitization and low back pain, making NGF a possible therapeutic target. However, current anti-NGF therapeutics have limited efficacy and safety concerns. Mechanisms leading to increased NGF in the disc are poorly understood and the molecular signaling mechanisms regulating NGF in inflammatory mediator rich environments, such as a degenerating disc, are unknown. During degeneration, proteoglycans and extra-cellular matrix (ECM) proteins are degraded and fragmented. ECM fragments can act as endogenous danger signal ligands for toll-like receptors (TLR). TLR activation induces cytokine and chemokine expression, and could thus regulate expression of inflammatory mediators, such as IL-1β or TNFα, during disc degeneration. NGF is often increased in environments with elevated levels of inflammatory mediators. Therefore, we hypothesized that TLR activation in the disc induces NGF expression. Materials and MethodsNon-degenerate human intervertebral discs from organ donors without a history of low back pain were collected for cell isolation. NP and AF tissues were separated and enzymatically digested. Cells were treated with IL-1β (control), peptidoglycan (PGN, TLR2 agonist) and lipopolysaccharide (LPS, TLR4 agonist). Neutralizing antibodies against TLR2 were used to prevent TLR2 activation. Activated cell-signaling pathways following IL-1β and PGN treatment were evaluated by western blot and immunofluorescence. Small molecule inhibitors blocking p38 MAPK (SB203580) and NF-κB (BMS-345541) activity were added to cell cultures in combination with IL-1β and PGN. NGF gene expression was evaluated by qRT-PCR after 6, 12 and 24 hours, and NGF protein levels were examined by western blot and ELISA after 48 hours. ResultsTLR 2 activation significantly increased NGF gene expression in NP and AF cells following 6, 12 and 24 hours of treatment, while TLR 4 activation had little effect on NGF expression. TLR 2 activation significantly increased NGF protein secretion after 48 hours in NP and AF cells while TLR 4 activation did not increase NGF protein levels. TLR 2 neutralization with antibodies showed that TLR 2 is required for PGN induced NGF expression. TLR 2 activation of the p38 MAPK, ERK1/2, JNK and NF-κB signaling pathways was analyzed using phosphorylation specific antibodies. TLR activation increased p38 MAPK, ERK1/2 and p65 (NF- κB pathway) phosphorylation in disc cells compared with untreated cells. Furthermore, immunofluorescence found that TLR activation induces p65 translation to the nucleus, indicative of NF-κB signaling. Inhibiting NF-κB signaling decreased TLR 2 induced NGF expression. ConclusionThis study found that TLR 2 activation directly regulates NGF expression via NF-κB signaling in human intervertebral disc cells. These findings represent a novel regulatory mechanism of NGF in the IVD. In the central nervous system NF-κB distinct signaling pathways regulate NGF. Therefore, these finding may provide therapeutic strategies to target NGF and low back pain without affecting the central nervous system.

Basic Research on Neurotrophic Factors and Its Application to Medical Uses

The author has studied nerve growth factor (NGF) and its family of neurotrophic factors (neurotrophins) for over 40 years. During the first 20 years, my laboratory established a highly sensitive enzyme immunoassay for NGF and analyzed the regulatory mechanism of NGF synthesis in cultured primary cells. Fibroblast cells cultured from peripheral organs such as the heart and astrocytes from the brain produced a substantial amount of NGF in a growth-dependent manner. Furthermore, synthesis of NGF in these cells could be upregulated by catechol compounds including catecholamines. This observation might explain a physiological relation between the level of NGF mRNA and the density of innervation in the peripheral sympathetic nervous systems. Over the subsequent 20 years, my laboratory investigated the physiological functions of neurotrophic factors, including neurotrophins, during development or post-injury and found that brain-derived neurotrophic factor (BDNF) plays a role in the formation of the laminar structure of the cerebral cortex. In addition, my laboratory discovered that endogenous glial cell line-derived neurotrophic factor (GDNF) contributes to the amelioration of motor activity after spinal cord injury. Therefore we aimed to develop low-molecular weight compounds that generate neurotrophic factor-like intracellular signals to protect or ameliorate neurological/psychiatric diseases. 2-Decenoic acid derivatives and other similar molecules could protect or ameliorate in animal models of mood disorders such as depression and enhance recovery from spinal cord injury-induced motor paralysis. Compounds that can generate neurotrophin-like signals in neurons are expected to be developed as therapeutic drugs for certain neurological or psychiatric disorders.

Hericium erinaceus, an amazing medicinal mushroom

Medicinal mushrooms have become a compelling topic because the bioactive compounds they contain promise a plethora of therapeutic properties. Hericium erinaceus commonly known as “Houtou” or “Shishigashira” in China and “Yamabushitake” in Japan, has commonly been prescribed in traditional Chinese medicine (TCM), because its consumption has been shown to be beneficial to human health. The species is found throughout the northern hemisphere in Europe, Asia, and North America. Hericium erinaceus has been firmly established as an important medicinal mushroom and its numerous bioactive compounds have been developed into food supplements and alternative medicines. However, the correspondence of the active components that cause the observed effects is often not clear. The mushroom as well as the fermented mycelia have been reported to produce several classes of bioactive molecules, including polysaccharides, proteins, lectins, phenols, and terpenoids. Most interestingly, two classes of terpenoid compounds, hericenones and erinacines, from fruiting bodies and cultured mycelia, respectively, have been found to stimulate nerve growth factor (NGF) synthesis. In this review we examine the scientific literature to explore and highlight the scientific facts concerning medicinal properties of H. erinaceus. We provide up-to-date information on this mushroom, including its taxonomy and a summary of bioactive compounds that appear related to the therapeutic potential of H. erinaceus.

Myenteric expression of nerve growth factor and the p75 neurotrophin receptor regulate axonal remodeling as a consequence of colonic inflammation in mice

Nerve growth factor (NGF) levels increase in response to inflammation of the mammalian colon. The precise cellular sources of colonic NGF synthesis, however, remain elusive. Using lines of transgenic mice that express enhanced green fluorescent protein (EGFP) under the control of the NGF promoter, we found a subpopulation of adendritic EGFP+ neurons in the myenteric plexus. These colonic EGFP+ neurons display positive immunostaining for calretinin but not nitric oxide synthase 1 (NOS1) two biomarkers of mouse myenteric neurons. A loss of NGF expression in null mutant postnatal mice does not affect the survival of these EGFP+ neurons. Induction of colonic inflammation confirms local increases in NGF mRNA/protein levels, which coincide with heightened detection of EGFP by myenteric neurons. Though NOS1+ myenteric neurons display positive immunostaining for trkA (the receptor required for NGF binding/signaling), transgenic overexpression of NGF by smooth muscle cells in the colon does not alter the survival, somal size, or axonal density of trkA-expressing NOS1+ myenteric neurons. Mice lacking functional p75NTR (the second receptor required for NGF binding) exhibit significantly less axonal damage among NOS1+ myenteric neurons, in response to chemically induced colonic inflammation. Likewise, trkA-expressing sympathetic axons that innervate the myenteric ganglia display less damage in the absence of p75NTR. These data are the first to implicate calretinin+ myenteric neurons as a source of NGF in the murine colon, and that in response to colonic inflammation, increases in NGF can exaggerate damage of intrinsic NOS1+ axons and extrinsic sympathetic axons that co-express trkA and p75NTR.

Neurotrophic Activity of Cultured Cell Line U87 is Up-Regulated by Proline-Rich Polypeptide Complex and Its Constituent Nonapeptide.

Neurotrophins such as nerve growth factor (NGF) and brain-derived neurotrophic factor, as well as cytokines, for example, interleukin-6 (IL-6) play an important role in neuroprotection and in the control of the central nervous system (CNS) function. Reduced expression of neurotrophic factors can lead to dysregulation of neuron function and neuronal death. There is also evidence for mutual interactions between neurotrophins and IL-6. Therefore, the up-regulating the level of neuroprotective substances is one of the key manners to control the nervous system development and function. It can be a promising aim in the therapy of neurodegenerative disease in which the decreased level of neurotrophins is observed. In our recent studies, the role of proline-rich polypeptide complex (PRP) and its nonapeptide fragment (NP) in the regulation of neurotrophic activity in cultured astrocytes was shown. PRP and NP stimulate human astrocytoma cell line U87 to release the significant amounts of NGF to the extracellular space both in its precursor and mature form. We also provide the evidence that in NP-treated cells, the level of βNGF mRNA was increased. NP-treated cells used in this study produced also increasing amounts of IL-6. This finding indicates that PRP and its nonapeptide fragment NP up-regulate neurotrophic activity of U87 cell line by increase of NGF synthesis and its release into the extracellular space. It was also shown that NP-dependent increased production of IL-6 can enhance the NGF activity.

Effects of Comb Tooth Cap Medicinal Mushroom, Hericium ramosum (Higher Basidiomycetes) Mycelia on DPPH Radical Scavenging Activity and Nerve Growth Factor Synthesis.

The goal of this study was to evaluate the antioxidant effects of and nerve growth factor (NGF) synthesis caused by Hericium ramosum mycelia. Wild mushroom fruiting bodies were collected from nature to isolate their mycelia. Pieces of H. ramosum fruiting bodies were plated onto 90-mm Petri dishes with potato dextrose agar medium to isolate their mycelia. Antioxidant activity was measured using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity in vitro; the ethanol extract from H. ramosum mycelia (63.11 µmol Trolox/g) was more potent than that of other mushroom mycelia extracts. There was a proportional relationship (R2 = 0.7929) between DPPH radical scavenging activity and total phenolic content in extracts of different mushroom mycelia. We investigated the ability of H. ramosum mycelia to inducing NGF synthesis in vivo. Oral administration of H. ramosum mycelia significantly increased concentrations of NGF in the hippocampus of intact mice. These results are the first concerning antioxidant activity and NGF synthesis of H. ramosum mycelia. These mushroom mycelia could be useful as food and/or nutritional supplements because of certain biological functions.

Improvement of refractory schizophrenia on using Amyloban®3399 extracted from Hericium erinaceum

Nerve growth factor (NGF) is considered as a very promising candidate in the treatment of Alzheimer’s disease [1]. However, NGF is a protein that becomes inactive after oral administration. A breakthrough in treatment occurred with the discovery of a class of compounds derived from the Lion’s Mane mushroom (Yamabushitake, Hericium erinaceum), which stimulate the production of NGF [2,3]. Bioactive substances in H. erinaceum including hericenones, have the potential to repair neurological damage, improve brain function, and possibly prevent and treat Alzheimer’s disease. If the substances in H. erinaceum are able to cross the bloodebrain barrier, then NGF may act to repair neuronal function. Since early 1990s, Kawagishi and colleagues have been investigating the role of compounds derived from H. erinaceum in the treatment of dementia [4e6]. They found that H. erinaceum exhibited important bioactive properties, including the induction of NGF synthesis, inhibition of the cytotoxicity of amyloid beta peptide, and protection against neuronal cell death caused by oxidative or endoplasmic stress.

A comprehensive review of the therapeutic effects of Hericium erinaceus in neurodegenerative disease

Mushrooms are considered not only as food but also for source of physiologically beneficial medicines. The culinary-medicinal mushrooms may important role in the prevention of age-associated neurological dysfunctions, including Alzheimer's and Parkinson's diseases. Hericium erinaceus (H. erinaceus), is edible mushrooms, is a parasitic fungus that grows hanging off of logs and trees and well established candidate for brain and nerve health. H. erinaceus contains high amounts of antioxidants, beta-glucan, polysaccharides and a potent catalyst for brain tissue regeneration and helps to improve memory and cognitive functions. Its fruiting bodies and the fungal mycelia exhibit various pharmacological activities, including the enhancement of the immune system, antitumor, hypoglycemic and anti-aging properties. H. erinaceus stimulates the synthesis of Nerve Growth Factor (NGF) which is the primary protein nutrient responsible for enhancing and repairing neurological disorders. Especially hericenones and erinacines isolated from its fruitin body stimulate NGF, synthesis. This fungus is also utilized to regulate blood levels of glucose, triglycerides and cholesterol. H. erinaceus can be considered as useful therapeutic agents in the management and/or treatment of neurodegeneration diseases. However, this review focuses on in vitro, in vivo and clinical trials for neurodegerative disease.

Metrifonate, like acetylcholine, up-regulates neurotrophic activity of cultured rat astrocytes

BackgroundMetrifonate is an inhibitor of acetylcholinesterase (AChE). Several studies confirmed its positive effects on cognitive impairment in Alzheimer's disease but it was due to adverse events withdrawn from clinical trials. Based on the importance of astrocytes in physiological and pathological brain activities we investigated the impact of metrifonate and, for comparison, acetylcholine on intrinsic neurotrophic activity in these cells. MethodsMetabolic activity, intracellular adenosine 5′-triphosphate (ATP) levels and lactate dehydrogenase (LDH) release was measured to examine the impact of metrifonate on viability and integrity of cultured rat cortical astrocytes. The influence of metrifonate, acetylcholine and selective cholinergic ligands on nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) synthesis and secretion was determined by specific two-site enzyme immunoassays. ResultsExposure of cultured astrocytes to metrifonate displayed no toxic effects on cell viability. Metrifonate and acetylcholine potently and transiently elevated NGF and BDNF, but not NT-3, protein levels and secretion with different intensity and time frame of their maximal response. Stimulatory effect on NGF was mimicked by selective nicotinic receptor agonist nicotine and completely blocked by nicotinic antagonist mecamylamine. The impact on BDNF synthesis was mimicked by muscarinic receptor agonist pilocarpine and abolished by selective muscarinic antagonist scopolamine. ConclusionsMetrifonate up-regulates astrocytic NGF and BDNF synthesis in the same manner as acetylcholine, their effect depends on different cholinergic pathways. These results suggest a trophic role of metrifonate, based on a well-known neurotrophic activity of NGF and BDNF in vivo.

Neurotrophins and pain

Neurotrophins are a family of trophic factors well known for their effects on neuronal survival, growth and neuronal differentiation. During the last decade, a large literature has shown in humans and in animal models that nerve growth factor (NGF) is a peripheral mediator of pain, especially in the states of inflammatory pain. NGF synthesis is indeed increased in a wide variety of inflammatory diseases and NGF neutralizing molecules are effective analgesic agents in these models of persistent pain. Therapeutical strategies targeting the sequestering of NGF did yield very encouraging results in clinical trials (stages II and III) but have been on hold since 2010 due to potential harmful effects in combination with non-steroid anti-inflammatory drug. NGF regulates the expression of a second neurotrophin, Brain Derived Neurotrophic Factor (BDNF), in nociceptors. BDNF is released where nociceptors are activated, and it acts as a modulator of pain in the central nervous system and is involved in central sensitization.

Induction of nerve growth factor expression and release by mechanical and inflammatory stimuli in chondrocytes: possible involvement in osteoarthritis pain

IntroductionNerve growth factor (NGF) level is increased in osteoarthritis (OA) joints and is involved in pain associated with OA. Stimuli responsible for NGF stimulation in chondrocytes are unknown. We investigated whether mechanical stress and proinflammatory cytokines may influence NGF synthesis by chondrocytes.MethodsPrimary cultures of human OA chondrocytes, newborn mouse articular chondrocytes or cartilage explants were stimulated by increasing amounts of IL-1β, prostaglandin E2 (PGE2), visfatin/nicotinamide phosphoribosyltransferase (NAMPT) or by cyclic mechanical compression (0.5 Hz, 1 MPa). Before stimulation, chondrocytes were pretreated with indomethacin, Apo866, a specific inhibitor of NAMPT enzymatic activity, or transfected by siRNA targeting visfatin/NAMPT. mRNA NGF levels were assessed by real-time quantitative PCR and NGF released into media was determined by ELISA.ResultsUnstimulated human and mouse articular chondrocytes expressed low levels of NGF (19.2 ± 8.7 pg/mL, 13.5 ± 1.0 pg/mL and 4.4 ± 0.8 pg/mL/mg tissue for human and mouse articular chondrocytes and costal explants, respectively). Mechanical stress induced NGF release in conditioned media. When stimulated by IL-1β or visfatin/NAMPT, a proinflammatory adipokine produced by chondocytes in response to IL-1β, a dose-dependent increase in NGF mRNA expression and NGF release in both human and mouse chondrocyte conditioned media was observed. Visfatin/NAMPT is also an intracellular enzyme acting as the rate-limiting enzyme of the generation of NAD. The expression of NGF induced by visfatin/NAMPT was inhibited by Apo866, whereas IL-1β-mediated NGF expression was not modified by siRNA targeting visfatin/NAMPT. Interestingly, PGE2, which is produced by chondrocytes in response to IL-1β and visfatin/NAMPT, did not stimulate NGF production. Consistently, indomethacin, a cyclooxygenase inhibitor, did not counteract IL-1β-induced NGF production.ConclusionsThese results show that mechanical stress, IL-1β and extracellular visfatin/NAMPT, all stimulated the expression and release of NGF by chondrocytes and thus suggest that the overexpression of visfatin/NAMPT and IL-1β in the OA joint and the increased mechanical loading of cartilage may mediate OA pain via the stimulation of NGF expression and release by chondrocytes.

Analysis of cyathane-type diterpenoids from Cyathus striatus and Hericium erinaceus by high-resolution MALDI MS imaging

Fungal secondary metabolites in both fruiting bodies and pellets from submerged cultures of basidiomycetes were analyzed by atmospheric pressure matrix-assisted laser desorption/ionization-mass spectrometry imaging at a lateral resolution of 15μm, a mass resolution of 140,000 at m/z 200 and a mass accuracy of better than 2ppm. The striatals A, B, C, and D, and a number of erinacine type metabolites were detected in the basidiomycetes Cyathus striatus and Hericium erinaceus, respectively. The two fungi were selected as model species, as they are well-known for efficient production of terpenoid secondary metabolites with interesting biological activities, e.g., antibacterial, fungicidal, cytotoxic properties, and stimulating effects on nerve growth factor synthesis. The localization of metabolites revealed a mostly homogeneous distribution of the striatals in the pellets of C. striatus, while a concentration gradient, increasing to the center, was observed in the pellets of H. erinaceus. A mostly homogeneous distribution of metabolites was also found in the fruiting body of H. erinaceus.

Familial dysautonomia model reveals Ikbkap deletion causes apoptosis of Pax3+ progenitors and peripheral neurons.

Familial dysautonomia (FD) is a devastating developmental and progressive peripheral neuropathy caused by a mutation in the gene inhibitor of kappa B kinase complex-associated protein (IKBKAP). To identify the cellular and molecular mechanisms that cause FD, we generated mice in which Ikbkap expression is ablated in the peripheral nervous system and identify the steps in peripheral nervous system development that are Ikbkap-dependent. We show that Ikbkap is not required for trunk neural crest migration or pathfinding, nor for the formation of dorsal root or sympathetic ganglia, or the adrenal medulla. Instead, Ikbkap is essential for the second wave of neurogenesis during which the majority of tropomyosin-related kinase A (TrkA(+)) nociceptors and thermoreceptors arise. In its absence, approximately half the normal complement of TrkA(+) neurons are lost, which we show is partly due to p53-mediated premature differentiation and death of mitotically-active progenitors that express the paired-box gene Pax3 and give rise to the majority of TrkA(+) neurons. By the end of sensory development, the number of TrkC neurons is significantly increased, which may result from an increase in Runx3(+) cells. Furthermore, our data demonstrate that TrkA(+) (but not TrkC(+)) sensory and sympathetic neurons undergo exacerbated Caspase 3-mediated programmed cell death in the absence of Ikbkap and that this death is not due to a reduction in nerve growth factor synthesis. In summary, these data suggest that FD does not result from a failure in trunk neural crest migration, but rather from a critical function for Ikbkap in TrkA progenitors and TrkA(+) neurons.