Relation between plasma brain-derived neurotrophic factor and nerve growth factor in the male patients with alcohol dependence

Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) are thought to be related to neuroprotection in cell culture and animal studies. Our aim was to verify the changes in human plasma BDNF and NGF concentrations induced by chronic alcohol use. Forty-one male patients with alcohol dependence were sampled the next morning of admission and compared with 41 healthy male subjects. Plasma BDNF and NGF were assayed using an enzyme-linked immunosorbent assay (ELISA). Mean plasma BDNF level was significantly higher in the patients with alcohol dependence (3502.21+/-1726.9 pg/mL) compared with the healthy subjects (861.75+/-478.9 pg/mL) (P=.000). Mean plasma NGF level was also significantly higher in patients with alcohol dependence (137.64+/-32.7 pg/mL) than in healthy subjects (112.61+/-90.2 pg/mL) (P=.012). Plasma BDNF and NGF levels showed significant negative correlation in alcohol dependence group (r=-0.388, P=.012). Increased plasma BDNF and NGF with negative correlation in alcohol-dependent patients may have some role in the regeneration of damage done by chronic alcohol use.

Neuroprotection by NGF and BDNF against neurotoxin-exerted apoptotic death in neural stem cells are mediated through Trk receptors, activating PI3-kinase and MAPK pathways

Neural stem cells (NSC) undergo apoptotic cell death during development of nervous system and in adult. However, little is known about the biochemical regulation of neuroprotection by neurotrophin in these cells. In this report, we demonstrate that Staurosporine (STS) and Etoposide (ETS) induced apoptotic cell death of NSC by a mechanism requiring Caspase 3 activation, poly (ADP-ribose) polymerase and Lamin A/C cleavage. Although C17.2 cells revealed higher mRNA level of p75 neurotrophin receptor (p75(NTR)) compared with TrkA or TrkB receptor, neuroprotective effect of both nerve growth factor (NGF) and brain-derived growth factor (BDNF) mediated through the activation of tropomyosin receptor kinase (Trk) receptors. Moreover, both NGF and BDNF induced the activation of the phosphatidylinositide 3 kinase (PI3K)/Akt and the mitogen-activated protein kinase (MAPK) pathway. Inhibition of Trk receptor by K252a reduced PARP cleavage as well as cell viability, whereas inhibition of p75(NTR) did not affect the effect of neurotrophin on neurotoxic insults. Thus our studies indicate that the protective effect of NGF and BDNF in NSC against apoptotic stimuli is mediated by the PI3K/Akt and MAPK signaling pathway via Trk receptors.

NGF and BDNF: from nerves to adipose tissue, from neurokines to metabokines

Neurotrophins, particularly, NGF and BDNF are now well recognized to mediate a dizzying number of trophobiological effects, ranging from the Rita Levi-Montalcini's neurotrophic through immunotrophic to metabotrophic effects.These are implicated in the pathogenesis of various diseases including neuropsychiatric and cardiometabolic diseases, such as dementia, depression, type 2 diabetes and obesity that may express a common phenotype and coexistence. Recently, adipobiology (adiposcience) as become a focus of numerous studies showing that the adipose tissue is the body's largest endocrine organ producing multiple signaling proteins, including NGF and BDNF, all these dubbed adipokines. On the basis of our and other authors' evidence that low NGF and/or BDNF levels are found in cardiometabolic diseases (atherosclerosis, obesity, type 2 diabetes, metabolic syndrome), a hypothesis of a critical role of neuro-metabotrophic deficit in the pathogenesis of these diseases has been raised. Since NGF and BDNF also exerts various synaptotrophic effects involved in cognitive enhancement, this hypothesis might also be related to neuropsychiatric diseases such as dementia, depression, schizophrenia, autism, Rett syndrome, anorexia nervosa, and bulimia nervosa. Finally, NGF- and BDNF-based therapeutic approach, including ampakines, antidepressants, selective deacetylase inhibitors, statins, peroxisome proliferator-activated receptor gamma agonists, and "brain food" and calorie restriction, is outlined.

The roles of nerve growth factor and cholecystokinin in the enhancement of morphine analgesia in a rodent model of central nervous system inflammation

Animal models of inflammatory pain are characterized by the release of inflammatory mediators such as cytokines and neurotrophic factors, and enhanced analgesic sensitivity to opioids. In this study, we examine the mechanisms underlying this effect, in particular the roles of cholecystokinin (CCK) and nerve growth factor (NGF), in an animal model of central nervous system (CNS) inflammation induced by spinal administration of lipopolysaccharide (LPS). Although spinal administration of LY-225910 (25 ng), a CCK-B antagonist, enhanced morphine analgesia in naïve rats, it was unable to do so in LPS-treated animals. Conversely, spinal CCK-8S administration (1 ng) decreased morphine analgesia in LPS-treated rats, but not in naïve animals. Further, spinal anti-NGF (3 microg) was able to reduce morphine analgesia in LPS-treated rats, but not in naïve animals, an effect that was reversed by spinal administration of LY-225910. While CCK-8S concentration was increased in spinal cord extracts of LPS animals as compared to controls, morphine-induced spinal CCK release in the extracellular space, as measured by in-vivo spinal cord microdialysis was inhibited in LPS animals as compared to controls, and this was reversed by anti-NGF pretreatment. Finally, chronic spinal administration of beta-NGF (7 microg/day) for 7 days enhanced spinal morphine analgesia, possibly by mimicking a CNS inflammatory state. We suggest that in intrathecally LPS-treated rats, spinal CCK release is altered resulting in enhanced morphine analgesia, and that this mechanism may be regulated to an important extent by NGF.

Nerve growth factor, sphingomyelins, and sensitization in sensory neurons

Because nerve growth factor (NGF) is elevated during inflammation, plays a causal role in the initiation of hyperalgesia, and is known to activate the sphingomyelin signalling pathway, we examined whether NGF and its putative second messenger, ceramide, could modulate the excitability of capsaicin-sensitive adult sensory neurons. Using the whole-cell patch-clamp recording technique, exposure of isolated sensory neurons to either 100 ng/mL NGF or 1 mmol/L N-acetyl sphingosine (C2-ceramide) produced a 3-4 fold increase in the number of action potentials (APs) evoked by a ramp of depolarizing current in a time-dependent manner. Intracellular perfusion with bacterial sphingomyelinase (SMase) also increased the number of APs suggesting that the release of native ceramide enhanced neuronal excitability. Glutathione, an inhibitor of neutral SMase, completely blocked the NGF-induced augmentation of AP firing, whereas dithiothreitol, an inhibitor of acidic SMase, was without effect. In the presence of glutathione and NGF, exogenous ceramide still enhanced the number of evoked APs, indicating that the sensitizing action of ceramide was downstream of NGF. To investigate the mechanisms of actions for NGF and ceramide, isolated membrane currents were examined. Both NGF and ceramide facilitated the peak amplitude of the TTX-resistant sodium current (TTX-R I(Na)) by approximately 1.5-fold and shifted the activation to more hyperpolarized voltages. In addition, NGF and ceramide suppressed an outward potassium current (I(K)) by ~35%. The inflammatory prostaglandin, PGE2, produced an additional suppression of I(K) after exposure to ceramide (~35%), suggesting that these agents might act on different targets. Based on the existing literature, it is not clear whether this NGF-induced sensitization is mediated by the high-affinity TrkA receptor or the low-affinity p75 neurotrophin receptor. Pretreatment with the p75 blocking antibody completely prevents the NGF-induced increase in the number of APs evoked by the current ramp. Although the sensitization by NGF was blocked, the antibody had no effect on the capacity of ceramide, a putative downstream signalling molecule, to enhance the excitability. Ceramide can be metabolized by ceramidase to sphingosine (Sph) and Sph to sphingosine 1-phosphate (S1P) by sphingosine kinase. It is well established that each of these products of sphingomyelin metabolism can act as intracellular signalling molecules. This raises the question as to whether the enhanced excitability produced by NGF was mediated directly by ceramide or required additional metabolism to Sph and/or S1P. Sph applied externally did not affect the neuronal excitability whereas internally perfused Sph augmented the number of APs evoked by the depolarizing ramp. Furthermore, internally perfused S1P enhanced the number of evoked APs. This sensitizing action of NGF, ceramide, and internally perfused Sph, were abolished by dimethylsphingosine (DMS), an inhibitor of sphingosine kinase. In contrast, internally perfused S1P enhanced the number of evoked APs in the presence of DMS. These observations support the idea that the metabolism of ceramide/Sph to S1P is critical for the sphingolipid-induced modulation of excitability. Thus, our findings indicate that the pro-inflammatory agent, NGF, can rapidly enhance the excitability of sensory neurons. This NGF-induced sensitization is mediated by activation of the sphingomyelin signalling pathway wherein intracellular S1P derived from ceramide, acts as an internal second messenger to regulate membrane excitability, however, the effector system whereby S1P modulates excitability remains undetermined.

Vasoactive peptides in the pathogenesis of psoriasis

Psoriasis, a chronic inflammatory skin disease, is believed to be exacerbated by stress. The exact mechanism of this phenomenon is not fully understood, however, it has been postulated that different substances released from dermal nerve endings during stress may take part in initiation or modulation of psoriasis. One of the most interesting group of mediators are polypeptides, also named as neuropeptides, that possess vasoactive properties. It was documented that these polypeptides could not only be released from nerve endings, but may also be directly synthesised in the skin and liberated from numerous dermal cells. Moreover, these substances are not only released by different cells, but may activate various cell types showing a wide spectrum of biological actions. Thus, this complex system of interactions seems to be important component of psoriatic pathological reaction. The significant role of these neuromediators has also been postulated in other chronic skin diseases, like palmoplantar pustulosis, atopic and irritant eczema, rosacea, lichen sclerosus, vitiligo, pigmented urticaria or prurigo nodularis. Among different neuropeptides, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide (VIP) and neuropeptide Y have been mostly studied in psoriasis.

[Influence of astrocyte-conditioned medium on the formation of synapses in neural stem cells: the role of neurotrophin proteins]

OBJECTIVE

To discuss whether neurotrophin proteins, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neural growth factor (NGF), in the astrocyte-conditioned medium (ACM) are involved in the synapse formation in neural stem cells (NSCs).

METHODS

(1) Cells derived from a pheochromocytoma of the rat adrenal medulla of the line PC12 were induced by amyloid-beta protein (Abeta)1-40 for 0, 4, 6, 12, and 24 h respectively. Then part of these PC12 cells underwent flow cytometry to examine the apoptotic rates. Different cells were added into Falcon Cell Culture Insert: Group A containing astrocytes isolated from Wistar rat, Group B with PC12 cells and astrocytes, Groups C1-C5 containing astrocytes and PC12 cells induced by Abeta(1-40) for 0, 4, 6, 12, and 24 h respectively, Group D1-5 with PC12 cells induced by Abeta(1-40) for 0, 4, 6, 12, and 24 h respectively, and Group E containing astrocytes induced by Abeta(1-40) for 6 h. Flow cytometry was used to detect the apoptotic rates of different groups. Double-antibody sandwich ELISA was used to detect the levels of BDNF, NT-3, and NGF. (2) The different kinds of the astrocyte-conditioned medium as described above were mixed with DMEM/F12 medium according to the proportion of 1:3 and then divided into 13 groups: Group I (Group A + NSCs), Group II (Group B + NSCs), Group III-VII (Groups C1-C5 + NSCs), Group VIII (NSCs without ASM), Group IX-XIII (Groups D1-D5 + Mscs), and Group XIV (Group E + NSCs). The expression of synaptophysin and growth-associated protein-43 (GAP-43 protein) were detected by co-focal laser scanning microscopy. The number of mature synapse was observed by transmission electron microscope(TEM).

RESULTS

Flow cytometry showed that the apoptotic rates of the PC12 cells were low 0, 2, and 4 h after Abeta(1-40) induction, with the peak 6 h after induction (P < 0.05). The BDNF total protein level in the ACM of Group C3 was the highest (A = 1.53 +/- 0.25) (P < 0.05). The expression levels of synaptophysin (A = 33.39 +/- 2.71) and GAP-43 (A = 49.18 +/- 6.45), and the mature synapse number of NSCs (4.70 +/- 0.52 synapse/field of vision) of Group V were the highest in comparison with the other groups (all P < 0.05).

CONCLUSION

After incubation of astrocytes with Abeta(1-40)-induced PC12 cells(Abeta-PC12), the ACM induces the synapse formation in the NSCs. The BDNF in the ACM is probably involved in this process.

Intra-axonal translation and retrograde trafficking of CREB promotes neuronal survival

During development of the nervous system, axons and growth cones contain mRNAs such as beta-actin, cofilin and RhoA, which are locally translated in response to guidance cues. Intra-axonal translation of these mRNAs results in local morphological responses; however, other functions of intra-axonal mRNA translation remain unknown. Here, we show that axons of developing mammalian neurons contain mRNA encoding the cAMP-responsive element (CRE)-binding protein (CREB). CREB is translated within axons in response to nerve growth factor (NGF) and is retrogradely trafficked to the cell body. In neurons that are selectively deficient in axonal CREB transcripts, increases in nuclear pCREB, CRE-mediated transcription and neuronal survival elicited by axonal application of NGF are abolished, indicating a signalling function for axonally synthesized CREB. These studies identify a signalling role for axonally derived CREB, and indicate that signal-dependent synthesis and retrograde trafficking of transcription factors enables specific transcriptional responses to signalling events at distal axons.

Pro-NGF, sortilin, and p75NTR: potential mediators of injury-induced apoptosis in the mouse dorsal root ganglion

The nerve growth factor precursor (pro-NGF) may function as a death-inducing ligand that mediates its apoptotic effects via p75NTR. Pro-NGF-induced apoptosis is postulated to be dependent upon membrane expression of the sortilin receptor, which interacts with p75NTR to promote a high-affinity binding site for pro-NGF. Here, we explore the expression of pro-NGF, sortilin and p75NTR in the mouse lumbar dorsal root ganglion (DRG) to understand the potential for this trimeric signaling complex to function in injury-induced neuronal death of DRG neurons. Our results reveal the expression of all 3 components within the DRG and that a subpopulation of neurons coexpresses sortilin and p75NTR. Following sciatic nerve transection, the expression of these proteins appears insensitive to injury; however, the majority of small p75NTR-sortilin coexpressing neurons are lost 25 days after sciatic nerve transection. These results propose pro-NGF-induced, p75NTR-sortilin-mediated neuronal death as a critical aspect of nerve injury-induced death in the DRG.

Nerve growth factor beta/pro-nerve growth factor and their receptors in normal human oral mucosa

Nerve growth factor beta (NGF-beta) and its precursor proNGF are important for the differentiation and survival of neurons and dermal keratinocytes. The aim of this study was to determine the role that NGF might play in the differentiation and wound healing of oral mucosa. Cultured normal human oral mucosal keratinocytes expressed mRNA for NGF-beta/proNGF and for their receptors TrkA and p75(NTR). Lysates from cultured oral mucosal keratinocytes did not contain detectable amounts of mature 14-kDa NGF-beta but did contain several NGF proforms with molecular weights between 32 and 114 kDa. Culture medium from oral mucosal keratinocytes contained 75 kDa proNGF. The addition of NGF-beta significantly enhanced the proliferation of oral mucosal keratinocyte cultures and in vitro scratch closure. Immunostaining of biopsies from normal oral mucosa showed the presence of proNGF in all epithelial layers. NGF staining was observed in the granular and upper spinous cell layers. TrkA immunoreactivity was detected in basal and parabasal cells, with weak to moderate staining in spinous and granular cell layers. p75(NTR) staining was seen in basal cell layers. These findings indicate that NGF-beta/proNGF have mitogenic and motogenic effects on oral mucosal keratinocytes and therefore may aid in the healing of oral wounds. Differential expression of NGF and NGF receptors throughout the epithelium suggests a role in epithelial differentiation.

Investigating the neurobiology of music: brain-derived neurotrophic factor modulation in the hippocampus of young adult mice

It has been shown that music might be able to improve mood state in people affected by psychiatric disorders, ameliorate cognitive deficits in people with dementia and increase motor coordination in Parkinson patients. Robust experimental evidence explaining the central effects of music, however, is missing. This study was designed to investigate the effect of music on brain neurotrophin production and behavior in the mouse. We exposed young adult mice to music with a slow rhythm (6 h/day; mild sound pressure levels, between 50 and 60 db) for 21 consecutive days. At the end of the treatment, mice were tested for passive avoidance learning and then killed for analysis of brain-derived neurotrophic factor (BDNF) and nerve growth factor with enzyme-linked immunosorbent assay (ELISA) in selected brain regions. We found that music-exposed mice showed increased BDNF, but not nerve growth factor in the hippocampus. Furthermore, we observed that music exposure significantly enhanced learning performance, as measured by the passive avoidance test. Our results demonstrate that exposure to music can modulate the activity of the hippocampus by influencing BDNF production. Our findings also suggest that music exposure might be of help in several central nervous system pathologies.

Src and FAK are key early signalling intermediates required for neurite growth in NGF-responsive adult DRG neurons

Axonal regeneration is influenced by factors in the extracellular environment, including neurotrophins, such as NGF, and adhesion molecules, such as laminin. The provision of both NGF and a permissive substrate to cultured adult NGF-responsive DRG neurons results in enhanced levels of neurite growth not achievable by either factor alone. In this study, we have investigated the early signalling events that contribute to NGF and laminin-induced neurite growth. Adult NGF-responsive DRG neurons were plated on poly-d-lysine for 2 h then stimulated with NGF, laminin, or laminin plus NGF for 10 min, 1 h, or 6 h. Signalling pathways were subsequently analysed using Western blotting and pharmacological inhibition of specific signalling components. While activation of the various signalling intermediates (Src, FAK, Akt, MAPK) could be detected as early as 10 min-1 h after stimulation, significant neurite growth was observed mainly at the 6 h time point. The results of the time course experiments showed differential activation of the signalling intermediates. Src was activated by all treatments (NGF, laminin and the combination) at the earliest time point analysed, 10 min. NGF stimulation also resulted in detectable activation of FAK, Akt and MAPK by 10 min. However, laminin stimulation alone did not result in detectable activation of FAK, Akt or MAPK until the 1 h time point. Inhibition of either Src or FAK activity attenuated both laminin and/or NGF-induced PI 3-K/Akt and MEK/MAPK signalling pathways, as well as neurite growth. Downstream inhibition of Akt by Akt knockdown also blocked observed neurite growth, while inhibition of MEK/MAPK had no significant effect. Together, these results demonstrate that signalling underlying neurite growth can be detected within minutes of stimulation and provide a mechanism for the observed enhancement of neurite growth when both NGF and the permissive substrate, laminin, are provided.

Combinatorial treatments for promoting axon regeneration in the CNS: strategies for overcoming inhibitory signals and activating neurons' intrinsic growth state

In general, neurons in the mature mammalian central nervous system (CNS) are unable to regenerate injured axons, and neurons that remain uninjured are unable to form novel connections that might compensate for ones that have been lost. As a result of this, victims of CNS injury, stroke, or certain neurodegenerative diseases are unable to fully recover sensory, motor, cognitive, or autonomic functions. Regenerative failure is related to a host of inhibitory signals associated with the extracellular environment and with the generally low intrinsic potential of mature CNS neurons to regenerate. Most research to date has focused on extrinsic factors, particularly the identification of inhibitory proteins associated with myelin, the perineuronal net, glial cells, and the scar that forms at an injury site. However, attempts to overcome these inhibitors have resulted in relatively limited amounts of CNS regeneration. Using the optic nerve as a model system, we show that with appropriate stimulation, mature neurons can revert to an active growth state and that when this occurs, the effects of overcoming inhibitory signals are enhanced dramatically. Similar conclusions are emerging from studies in other systems, pointing to a need to consider combinatorial treatments in the clinical setting.

Neurotrophins and their receptors: roles in plasticity, neurodegeneration and neuroprotection

It is beyond doubt that the neurotrophin family of proteins plays key roles in determining the fate of the neuron, not only during embryonic development, but also in the adult brain. Neurotrophins such as NGF (nerve growth factor) and BDNF (brain-derived neurotrophic factor) can play dual roles: first, in neuronal survival and death, and, secondly, in activity-dependent plasticity. The neurotrophins manifest their effects by binding to two discrete receptor subtypes: the Trk (tropomyosin receptor kinase) family of RTKs (receptor tyrosine kinases) and the p75NTR (p75 neurotrophin receptor). The differential activation of these receptors by the mature neurotrophins and their precursors, the proneurotrophins, renders analysis of the biological functions of these receptors in the adult brain highly complex. Here, we briefly give a broad review of current knowledge of the roles of neurotrophins in the adult brain, including expression of hippocampal plasticity, neurodegeneration and exercise-induced neuroprotection.

Visceral hyperalgesia induced by neonatal maternal separation is associated with nerve growth factor-mediated central neuronal plasticity in rat spinal cord

Neonatal maternal separation (NMS) has been shown to trigger alterations in neuroendocrine, neurochemical and sensory response to nociceptive stimuli along the brain-gut axis. These alterations may be the result of a cascade of events that are regulated by neurotrophic factors. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for the development and maintenance of sensory neurons and for the formation of central pain circuitry. The present study aimed to investigate whether NMS causes changes in neuronal plasticity and the relationship of these changes in plasticity with the expression of NGF and its high affinity tyrosine kinase receptor A (TrkA) in the lumbosacral spinal cord in adult rats. Male Wistar rat pups were either subjected to 180 min daily of NMS or not handled (NH) for 13 consecutive days. The expression of NGF and TrkA was examined in NH and NMS rats with or without colorectal distention (CRD) as determined by Western blot analysis and immunohistochemistry. The present results of Western blot analysis indicated NMS and CRD have a significant effect on NGF protein level in the lumbosacral spinal cord of rats. Assessments of optical densities revealed that NMS enhanced TrkA-ir fiber densities in laminae I-III and laminae V-VI of rats in both conditions with or without CRD. Double immunofluorescence revealed that TrkA co-expressed with calcitonin gene-related peptide (CGRP) in afferent fibers, while no significant difference in terms of the intensity of TrkA-ir in these fibers was found among groups. Quantitative analysis of TrkA-ir neurons indicated a significant interactive effect of NMS and CRD on the mean number of TrkA-ir neurons in laminae V-VI of rats, in which significant difference was found between NMS+CRD and NH+CRD. Double immunofluorescence of TrkA and Fos showed that CRD has a significant effect on TrkA expression in Fos-positive neurons in laminae V-VI and lamina X of rats, while no significant difference was found between NMS+CRD and NH+CRD. These results demonstrate that NMS induced alterations in NGF protein level and TrkA expression in adult rat spinal cord and indicate that NGF is a crucial mediator for the changes in neuronal plasticity that occur in NMS-induced visceral hyperalgesia.

Intravesical Botulinum Toxin A Injections Plus Hydrodistension Can Reduce Nerve Growth Factor Production and Control Bladder Pain in Interstitial Cystitis

OBJECTIVES

To investigate the level of nerve growth factor (NGF) mRNA in bladder tissue and the effect of botulinum toxin A (BTX-A) treatment in patients with interstitial cystitis (IC).

METHODS

A total of 19 patients with IC were treated with 100 U or 200 U of intravesical BTX-A injections followed by cystoscopic hydrodistension 2 weeks later. Bladder mucosa biopsies were performed before BTX-A injection and immediately after hydrodilation and in 12 controls. The NGF mRNA and protein levels in bladder tissues were assessed by real-time polymerase chain reaction and immunohistochemistry studies to determine differences in NGF expression between patients with IC before and after BTX-A treatment and compare with controls.

RESULTS

At 3 months, 14 patients had symptomatic improvement (responders) and 5 did not (nonresponders). The NGF mRNA levels at baseline in the overall IC patient group were significantly greater than those in the controls (0.65 +/- 0.33 versus 0.42 +/- 0.25, P = 0.046). At 2 weeks after BTX-A treatment, the NGF mRNA levels had decreased to 0.47 +/- 0.23 (P = 0.002, compared with baseline) and were no longer significantly different from those of the controls. The NGF mRNA levels decreased significantly in responders and were significantly decreased after BTX-A in 11 patients with a visual analog pain scale reduction of 2 or more. The immunoreactivity study of bladder tissue from patients with IC showed greater NGF density at baseline compared with controls, but the difference was no longer significant after successful BTX-A treatment.

CONCLUSIONS

Intravesical BTX-A injections plus hydrodistension reduce bladder pain in patients with IC. The NGF levels in the bladder tissue were significantly increased in patients with IC and decreased to normal level after treatment in responders.

Homo obesus: a metabotrophin-deficient species. Pharmacology and nutrition insight

In most countries the prevalence of obesity now exceeds 15%, the figure used by the World Health Organization to define the critical threshold for intervention in nutritional epidemics. Here we describe Homo obesus (man the obese) as a recent phenotypic expression of Homo sapiens. Specifically, we classified Homo obesus as a species deficient of metabotrophic factors (metabotrophins), including endogenous proteins, which play essential role in the maintenance of glucose, lipid, energy and vascular homeostasis, and also improve metabolism-related processes such as inflammation and wound healing. Here we propose that pharmaceuticals, nutraceuticals and xenohormetics targeting transcriptional, secretory and/or signaling pathways of metabotrophins, particularly adiponectin, nerve growth factor, brain-derived neurotrophic factor, interleukin-10, and sirtuins, might be new tools for therapy of Homo obesus. Brief comment is also given to (i) exogenous metabotrophic agents represented by various classes of drugs, and (ii) adiponutrigenomics of lifespan.

Role of nerve growth factor and its receptor in the morphogenesis of neural tube in early chick embryo

Expression of p75 nerve growth factor receptor (p75(NTR)) in the early neurogenesis of chick embryo showed that nerve growth factor receptor (NGFR) is localized in presumptive neuroectoblast and endoblast in the chick gastrula but not in the mesoblast. By stages 9, 10, and 11, NGFR positive cells were located distinctly in the region where the neural folds converge, meet and fuse. NGFR expression was also seen in developing notochord and somites, wherein the reaction was localized on the cell surfaces. Strong p75(NTR) reaction was seen on the roof of the neural tube where it detaches from the head ectoderm by stage 12. The study revealed that p75(NTR) is co-expressed with NGF in the same developmental stage(s) and in areas, where cell death occurs during neuronal development. Further, when the endogenous levels of NGF signaling were blocked by anti-NGF antibody, abnormalities were observed at the anterior end of the neural tube formation. As a result, embryos showed open neural tubes and a few were bent on one side of the body axis. In a small proportion of embryos, diffused somites were observed. The findings supports and confirms our previous study that NGF signaling plays a significant role in the shaping of neural tube in chick embryos through p75(NTR)-NGF receptor.

Role of urothelial nerve growth factor in human bladder function

AIMS

To test whether nerve growth factor (NGF) concentration in human bladder urothelium/suburothelium is related to detrusor overactivity (DO), bladder sensation, detrusor contractility, or other aspects of lower urinary tract function.

MATERIALS AND METHODS

Concentration of NGF was measured (using ELISA) in superficial bladder biopsies from 27 women (mean age 52 years, range 22-82) after comprehensive video-urodynamics and bladder diary. Approximately half (12/27) showed clear DO and half did not.

RESULTS

There was no evidence for increased NGF concentration in subjects with DO (association negative by Mann-Whitney test, P = 0.23). NGF was not significantly associated with two measures of detrusor contractility (Spearman's r = -0.29, P = 0.17; r = -0.20, P = 0.33); nor with four measures inversely related to sensation: volume at strong desire to void and maximum capacity on cystometry (r = -0.13, P = 0.53; r = -0.23, P = 0.28), and maximum voided volume and mean daytime voided volume on bladder diary (r = -0.29, P = 0.16; r = -0.16, P = 0.44). It was significantly associated with 24-hr urine output on bladder diary (Spearman's r = -0.55, P = 0.004).

CONCLUSIONS

Elevated NGF levels in human urothelium/suburothelium are not strongly associated with DO, detrusor contractility or increased bladder sensation. NGF levels are lower in subjects with higher 24-hr urine output. This observation is consistent with a role for NGF in an active process (trafficking) involved in bladder filling.

Nerve growth factor potentiates p53 DNA binding but inhibits nitric oxide-induced apoptosis in neuronal PC12 cells

NGF is recognized for its role in neuronal differentiation and maintenance. Differentiation of PC12 cells by NGF involves p53, a transcription factor that controls growth arrest and apoptosis. We investigated NGF influence over p53 activity during NO-induced apoptosis by sodium nitroprusside in differentiated and mitotic PC12 cells. NGF-differentiation produced increased p53 levels, nuclear localization and sequence-specific DNA binding. Apoptosis in mitotic cells also produced these events but the accompanying activation of caspases 1-10 and mitochondrial depolarization were inhibited during NGF differentiation and could be reversed in p53-silenced cells. Transcriptional regulation of PUMA and survivin expression were not inhibited by NGF, although NO-induced mitochondrial depolarization was dependent upon de novo gene transcription and only occurred in mitotic cells. We conclude that NGF mediates prosurvival signaling by increasing factors such as Bcl-2 and p21(Waf1/Cip1) without altering p53 transcriptional activity to inhibit mitochondrial depolarization, caspase activation and apoptosis.