VEGF and ALS: the luckiest growth factor?

VEGF and Neuronal Survival

Vascular endothelial growth factor (VEGF) is well known for its angiogenic activity, but recent evidence has revealed a neuroprotective action of this factor on injured or diseased neurons. In the present review, we summarize the most relevant findings that have contributed to establish a link between VEGF deficiency and neuronal degeneration. At issue, 1) mutant mice with reduced levels of VEGF show adult-onset muscle weakness and motoneuron degeneration resembling amyotrophic lateral sclerosis (ALS), 2) administration of VEGF to different animal models of motoneuron degeneration improves motor performance and ameliorates motoneuronal degeneration, and 3) there is an association between low plasmatic levels of VEGF and human ALS. Altogether, the results presented in this review highlight VEGF as an essential motoneuron neurotrophic factor endowed with promising therapeutic potential for the treatment of motoneuron disorders.

A Fluorescent Aptasensor Based on Assembled G-Quadruplex and Thioflavin T for the Detection of Biomarker VEGF165

VEGF165, a regulator of angiogenesis, has been widely used as a serum biomarker for a number of human diseases, including cancer, rheumatoid arthritis, bronchial asthma, and diabetic eye disease. The rapid, accurate, and convenient detection of VEGF165 is a crucial step in effective healthcare monitoring, disease diagnosis, and prognosis assessment. In this study, a fluorescent aptasensor based on an assembled G-quadruplex and the signal molecule ThT was developed for VEGF165 detection. First, G-rich DNA fragments were assembled at both ends of the anti-VEGF165 aptamer, and the B-DNA form was converted into a G-quadruplex structure aptamer (G4-Apt). Then, ThT was introduced, and the G-quadruplex significantly enhanced the fluorescence intensity of the bound ThT. When VEGF165 was present, the higher affinity of the aptamer to the target protein allowed the G4-Apt/VEGF165 complex to form and release ThT, which emitted only weak fluorescence in the free state. Therefore, the aptasensor exhibited a good linear detection window from 1.56 to 25 nM VEGF165, with a limit of detection of 0.138 nM. In addition, the aptasensor was applied to detect VEGF165 in clinical serum samples, showing good accuracy, reproducibility, and stability. These results indicate that our developed fluorescent aptasensor can potentially be a reliable, convenient, and cost-effective approach for the sensitive, specific, and rapid detection of the VEGF165 biomarker.

Involvement of vascular endothelial growth factor in schizophrenia

Vascular endothelial growth factor (VEGF), which acts as an angiogenic and neurotrophic factor, is involved the regulation of cerebral blood volume and flow in Schizophrenia (SCZ). Several evidence indicates that modification of brain blood circulation due to alterations in the VEGF system affects cognitive performance and brain function in patients with SCZ. The aim of this study is: 1) To analyze the literature data concerning the role of VEGF in modulating the angiogenic response in SCZ. These data are controversial because some studies found elevated VEGF serum levels of VEGF in patients with SCZ, whereas others demonstrated no significant differences between SCZ patients and controls. 2)To analyze the role of VEGF as a predictive factor on the effects of antipsychotics agents used in the treatment of SCZ. In this context, high VEGF levels, associated to better responses to antipsychotics, might be predictive of the use of first generation antipsycotic drugs, whereas low VEGF levels, expression of resistance to therapy, might be predictive for the use of second generation antipsycotic drugs.

Synthetic α5β1 integrin ligand PHSRN is proangiogenic and neuroprotective in cerebral ischemic stroke

Ischemic stroke is the leading cause of disability and death worldwide. An effective therapeutic approach is urgently needed. Stroke-induced angiogenesis and neurogenesis are essential mechanisms in the long-term repair. Extracellular matrix proteins are also involved in tissue self-repair. Recently, a PHSRN (Pro-His-Ser-Arg-Asn) peptide from the fibronectin synergistic motif that can promote wound healing in epithelia and induce endothelial proliferation and cancer cell migration was identified. The therapeutic potential of this peptide in stroke is unknown. Here, we examined the potential of PHSRN in stroke therapy using an ischemic rat model of middle cerebral artery occlusion (MCAO). PHSRN reduced the infarct volume in MCAO rats, improved neurological function, and alleviated motor function impairment. PHSRN targeted the damaged brain region and distributed to endothelial cells after intraperitoneal injection. PHSRN significantly promoted angiogenesis and vascular endothelial growth factor secretion through activation of integrin α5β1 and its downstream intracellular signals, e.g., focal adhesion kinase, Ras, cRaf, and extracellular-signal-regulated kinase. PHSRN treatment also stimulated neurogenesis in MCAO rats, and maintained neuronal survival and neuronal morphologic complexity via induction of VEGF secretion. Together, these results provide insights into the role of integrin α5β1 following ischemia and support the feasibility of using PHSRN peptide in stroke therapy.

Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

The VEGF gene polymorphism impacts brain volume and arterial blood volume

Vascular endothelial growth factor (VEGF) plays a critical role in the angiogenesis and proliferation of various types of cells such as neurons, astroglia, and endothelial cells in the brain. A common polymorphism in the VEGF gene (-2578 C/A) is associated with circulating VEGF levels, cancers and Alzheimer's disease. Nonetheless, the effects of this polymorphism on normal human brain volume, arterial blood volume, and blood supply remain unclear. In this study, the effects of this polymorphism on the total gray matter volume (TGMV) and total white matter volume (TWMV) using T1-weighted structural images and the total arterial blood volume (TABV) and mean cerebral blood flow (mCBF) during rest using arterial spin labeling (ASL) in 765 young adult humans were investigated. Voxel-by-voxel whole-brain analyses of these measures were also performed. Multiple regression analyses with age and sex as covariates revealed that the VEGF genotype (number of C alleles) was significantly and positively correlated with TGMV, TWMV, and TABV as well as with regional gray and white matter volumes in widespread areas and regional arterial blood volume in some areas with high arterial blood volume. However, these regional associations were not seen when the corresponding global signal was included as a covariate in the multiple regression analyses, indicating that we failed to obtain evidence of region-specific associations between these brain measures and the genotype. The results suggest that the VEGF-2578C allele, is associated with changes in the vascular system that lead to increased blood volume and larger brain volume. Hum Brain Mapp 38:3516-3526, 2017. © 2017 Wiley Periodicals, Inc.

scAAV9-VEGF prolongs the survival of transgenic ALS mice by promoting activation of M2 microglia and the PI3K/Akt pathway

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease that leads to paralysis and death three to five years after diagnosis in most patients. The disease is incurable, and the mechanism of motoneuron degeneration remains unknown, although research has demonstrated that activated microglia are involved in motor neuron death. Here, we used a simple method to deliver AAV9 virus by direct intrathecal injection and found that scAAV9-VEGF-165 improved the motor performance and prolonged the life span of SOD1-G93A mice. Furthermore, scAAV9-VEGF-165 activated the PI3K/Akt survival pathway and increased the level of Bcl-2, which contributed to the protection of motor neurons. Additionally, scAAV9-VEGF-165 attenuated the expression of classically activated (M1) microglial markers and enhanced the expression of alternatively activated (M2) microglial markers. Taken together, the results of our study suggest that simple, direct intrathecal injection of scAAV9-VEGF-165 may have a curative effect for ALS.

State of the field: An informatics-based systematic review of the SOD1-G93A amyotrophic lateral sclerosis transgenic mouse model

Numerous sub-cellular through system-level disturbances have been identified in over 1300 articles examining the superoxide dismutase-1 guanine 93 to alanine (SOD1-G93A) transgenic mouse amyotrophic lateral sclerosis (ALS) pathophysiology. Manual assessment of such a broad literature base is daunting. We performed a comprehensive informatics-based systematic review or 'field analysis' to agnostically compute and map the current state of the field. Text mining of recaptured articles was used to quantify published data topic breadth and frequency. We constructed a nine-category pathophysiological function-based ontology to systematically organize and quantify the field's primary data. Results demonstrated that the distribution of primary research belonging to each category is: systemic measures an motor function, 59%; inflammation, 46%; cellular energetics, 37%; proteomics, 31%; neural excitability, 22%; apoptosis, 20%; oxidative stress, 18%; aberrant cellular chemistry, 14%; axonal transport, 10%. We constructed a SOD1-G93A field map that visually illustrates and categorizes the 85% most frequently assessed sub-topics. Finally, we present the literature-cited significance of frequently published terms and uncover thinly investigated areas. In conclusion, most articles individually examine at least two categories, which is indicative of the numerous underlying pathophysiological interrelationships. An essential future path is examination of cross-category pathophysiological interrelationships and their co-correspondence to homeostatic regulation and disease progression.

Roles of vascular endothelial growth factor in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal devastating neurodegenerative disorder, involving progressive degeneration of motor neurons in spinal cord, brainstem, and motor cortex. Riluzole is the only drug approved in ALS but it only confers a modest improvement in survival. In spite of a high number of clinical trials no other drug has proved effectiveness. Recent studies support that vascular endothelial growth factor (VEGF), originally described as a key angiogenic factor, also plays a key role in the nervous system, including neurogenesis, neuronal survival, neuronal migration, and axon guidance. VEGF has been used in exploratory clinical studies with promising results in ALS and other neurological disorders. Although VEGF is a very promising compound, translating the basic science breakthroughs into clinical practice is the major challenge ahead. VEGF-B, presenting a single safety profile, protects motor neurons from degeneration in ALS animal models and, therefore, it will be particularly interesting to test its effects in ALS patients. In the present paper the authors make a brief description of the molecular properties of VEGF and its receptors and review its different features and therapeutic potential in the nervous system/neurodegenerative disease, particularly in ALS.

Decreased serum levels of the angiogenic factors VEGF and TGF-β1 in Alzheimer's disease and amnestic mild cognitive impairment

Growing evidence suggests that angiogenesis might represent a new pathogenic mechanism involved in the progression of Alzheimer's disease (AD). Vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) are two cytokines having a pivotal role in angiogenesis. In the present study, serum VEGF and TGF-β1 levels were measured with ELISA in 31 AD patients, 28 amnestic mild cognitive impairment (aMCI) patients and 29 controls. VEGF concentration in serum of AD patients was significantly lower than that in aMCI patients and controls (p<0.05). Serum VEGF levels in aMCI patients were also significantly decreased compared to controls (p<0.05). Serum TGF-β1 levels in AD patients were significantly lower than those in controls (p<0.05). There was a negative correlation between serum VEGF/TGF-β1 levels and the Clinical Dementia Rating (CDR) scores (p<0.05) and a positive correlation between serum VEGF levels and TGF-β1 levels (p<0.05). These observations suggest that angiogenesis might be involved in the onset process of AD and the decrease of angiogenic factors might be related to the severity of cognitive impairment.

The alteration of hypoxia inducible factor-1 (HIF-1) and its target genes in mood disorder patients

Recent studies suggest that the dysfunction of neural plasticity is associated with mood disorders. Hypoxia-inducible factor-1 (HIF-1), which is a transcriptional activator of vascular endothelial growth factor (VEGF), activates the cellular response to hypoxia. HIF-1 is ubiquitously expressed in all cells, including peripheral leukocytes. However, little is known about the role of HIF-1 in mood disorder. In the present study, we investigated the mRNA expression levels of HIF-1 (α and β) and its target genes (VEGF, GLUT1, PGK1, PFKFB3, and LDHA) in the peripheral white blood cells of patients with major depressive disorder (MDD) and bipolar disorder (BPD). We found increased expression of HIF- 1α and HIF-1β mRNA, as well as the target genes, VEGF, and PFKFB3 in both MDD and BPD patients in a depressive state compared to healthy control subjects. Furthermore, the mRNA expression levels of GLUT1, PGK1, and LDHA were increased in MDD patients in a depressive state compared to healthy control subjects. We also found increased expression of HIF-1α and LDHA mRNA in MDD patients in a remissive state, whereas the mRNA expression levels of other genes in a remissive state were comparable to those in healthy control subjects. There was no significant difference in mRNA expression levels of the genes examined among patients receiving any type of antidepressant or mood stabilizer. Our data suggest that altered expression of HIF-1 and its target genes mRNA in peripheral blood cells are associated-mainly in a state-dependent manner-with mood disorders (especially with MDD). In addition, altered expression of HIF-1 and its target genes may be associated with the pathophysiology of depression.

Bone marrow transplantation in hindlimb muscles of motoneuron degenerative mice reduces neuronal death and improves motor function

Bone marrow has proved to be an adequate source of stem cells for the treatment of numerous disorders, including neurodegenerative diseases. Bone marrow can be easily and relatively painlessly extracted from a patient or allogenic donor and then transplanted into the degenerative area. Here, the grafted cells will activate a number of mechanisms in order to protect, repair, and/or regenerate the damaged tissue. These properties make the bone marrow a feasible source for cell therapy. In this work, we transplanted bone marrow cells into a mouse model of motoneuron degeneration, with the particularity of placing the cells in the hindlimb muscles rather than in the spinal cord where neuronal degeneration occurs. To this end, we analyze the possibility for the transplanted cells to increase the survival rate of the spinal cord motoneurons by axonal-guided retrograde neurotrophism. As a result, the mice significantly improved their motor functions. This coincided with an increased number of motoneurons innervating the treated muscle compared with the neurons innervating the non-treated contralateral symmetric muscle. In addition, we detected an increase in glial-derived neurotrophic factor in the spinal cord, a neurotrophic factor known to be involved in the rescue of degenerating motoneurons, exerting a neuroprotective effect. Thus, we have proved that bone marrow injected into the muscles is capable of rescuing these motoneurons from death, which may be a possible therapeutic approach for spinal cord motoneuron degenerative diseases, such as amyotrophic lateral sclerosis.

-1154G/A and -2578C/A polymorphisms of the vascular endothelial growth factor gene in Tunisian Alzheimer patients in relation to beta-amyloid (1-42) and total tau protein

Recent evidences indicate that polymorphisms within the promoter region of the vascular endothelial growth factor (VEGF) gene may elevate the risk for Alzheimer's disease (AD). To further investigate, we have analyzed association between promoter polymorphisms of the VEGF gene in 93 AD patients and age and sex matched 113 controls from Tunisian population. The distribution of genotype and allele frequencies of the VEGF (-2578C/A) and (-1154G/A) polymorphisms did not differ significantly between AD and control groups (p>0.05). In the subgroup of ApoE varepsilon4 carriers, the -2578A was observed to be significantly higher in the AD patients than in the control individuals. After adjusting the data by gender, age and the ApoE varepsilon4 status using logistic regression, the -2578A allele was found to increase the risk for sporadic AD by 1.7-fold. The present study provides the evidence that the -2578A allele may be associated with the development of AD in the individuals with ApoE varepsilon4 allele. In addition, AD patients carrying the -2578A allele had lower Abeta42 (p=0.029) levels than those without this allele, particularly in subjects with ApoE varepsilon4 allele.

Inhibition of prolyl hydroxylase protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced neurotoxicity: model for the potential involvement of the hypoxia-inducible factor pathway in Parkinson disease

Hypoxia-inducible factor (HIF) plays an important role in cell survival by regulating iron, antioxidant defense, and mitochondrial function. Pharmacological inhibitors of the iron-dependent enzyme class prolyl hydroxylases (PHD), which target alpha subunits of HIF proteins for degradation, have recently been demonstrated to alleviate neurodegeneration associated with stroke and hypoxic-ischemic injuries. Here we report that inhibition of PHD by 3,4-dihydroxybenzoate (DHB) protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigral dopaminergic cell loss and up-regulates HIF-1alpha within these neurons. Elevations in mRNA and protein levels of HIF-dependent genes heme oxygenase-1 (Ho-1) and manganese superoxide dismutase (Mnsod) following DHB pretreatment alone are also maintained in the presence of MPTP. MPTP-induced reductions in ferroportin and elevations in nigral and striatal iron levels were reverted to levels comparable with that of untreated controls with DHB pretreatment. Reductions in pyruvate dehydrogenase mRNA and activity resulting from MPTP were also found to be attenuated by DHB. In vitro, the HIF pathway was activated in N27 cells grown at 3% oxygen treated with either PHD inhibitors or an iron chelator. Concordant with our in vivo data, the MPP(+)-elicited increase in total iron as well as decreases in cell viability were attenuated in the presence of DHB. Taken together, these data suggest that protection against MPTP neurotoxicity may be mediated by alterations in iron homeostasis and defense against oxidative stress and mitochondrial dysfunction brought about by cellular HIF-1alpha induction. This study provides novel data extending the possible therapeutic utility of HIF induction to a Parkinson disease model of neurodegeneration, which may prove beneficial not only in this disorder itself but also in other diseases associated with metal-induced oxidative stress.

VEGF PROMOTER HAPLOTYPE AND AMYOTROPHIC LATERAL SCLEROSIS (ALS)

Vascular endothelial growth factor (VEGF) is a cytokine essential for angiogenesis. A recent study found that haplotypes, determined by three SNPs (-2,578C/A, - 1,154 G/A, and - 634G/C) in the VEGF upstream promoter/leader sequence, were associated with risk of amyotrophic lateral sclerosis(ALS). We used samples and data from a case-control study to examine the relation of ALS to VEGF haplotype. Genotypes at each of the three polymorphic sites were determined using allele-specific primer extension reactions followed by MALDI-TOF. We found a 3-fold increased risk among individuals homozygous for the AAG or AGG haplotypes (95%CI = 0.7 - 13.4), consistent with the findings of the previous study. Given the wide confidence interval, our findings should be interpreted cautiously.

Mechanisms and targets for angiogenic therapy after stroke

Stroke remains a major health problem worldwide, and is the leading cause of serious long-term disability. Recent findings now suggest that strategies to enhance angiogenesis after focal cerebral ischemia may provide unique opportunities to improve clinical outcomes during stroke recovery. In this mini-review, we survey emerging mechanisms and potential targets for angiogenic therapies in brain after stroke. Multiple elements may be involved, including growth factors, adhesion molecules and progenitor cells. Furthermore, cross talk between angiogenesis and neurogenesis may also provide additional substrates for plasticity and remodeling in the recovering brain. A better understanding of the molecular interplay between all these complex pathways may lead to novel therapeutic avenues for tackling this difficult disease.

VEGF genetic variability is associated with increased risk of developing Alzheimer's disease

Specific polymorphisms within the vascular endothelial growth factor (VEGF) gene promoter region are of particular interest: VEGF variability has been associated with increased risk of developing a wide variety of disorders from diabetes to neurodegenerative diseases, suggesting functions not confined to its originally described vascular effects. A hypothetical loss of the VEGF-mediated neuroprotective effect has been proposed as a cause of neurodegenerative disorders. An impaired regulation of VEGF expression has been also reported in Alzheimer's disease (AD) pathogenesis. Recently, VEGF gene promoter polymorphisms have been associated with an increased risk for AD in the Italian population. Conversely, two subsequent studies failed to find a positive association between VEGF variability and greater risk for AD. To better clarify this issue, a meta-analysis of all published association studies has been performed. Overall, polymorphic variants within VEGF gene promoter confer greater risk for AD at least in the Italian population; the meta-analysis provides evidence of a role of the functional variant C(-2578)A in the pathogenesis of the disease, although the pooled odds ratio obtained represents a modest effect. These findings provide new evidence for an additional candidate genetic risk factor for AD that can be tested in further studies.

Glial cells in ALS: the missing link?

Amyotrophic lateral sclerosis (ALS) was initially known as Charcot's sclerosis, named after the French neurobiologist and physician Jean-Martin Charcot who first described this type of muscular atrophy in the early nineteenth century. In the United States, ALS became widely known as Lou Gehrig's disease after the famous baseball player who succumbed to the disease in the late 1930s. Currently, ALS is the most common motor neuron disease, with a worldwide incidence of 8 cases per 100,000 population per year. Familial forms constitute approximately 5% to 10% of all cases. Onset increases with age, with a peak in the seventh decade and a slight preponderance (relative risk, 1.3-1.5) among men compared with women. Rapid progression of motor neuron loss leads to death an average of 3 to 5 years after symptom onset. The cause of ALS remains unknown and there is still no curative therapy.

Single-nucleotide polymorphisms (SNPs) and haplotype analysis in vascular endothelial growth factor (VEGF) gene in the patients with Parkinson disease and lung cancer

The epidemiologic data on smoking in association with Parkinson disease (PD) is puzzling. A lower incidence of smoking-related malignancies, especially lung cancer, has been reported by several studies in the patients with PD. In this study, we investigated polymorphic variations in the vascular endothelial growth factor (VEGF) gene, which has been proposed having a pivotal role in progressive damage of nigral dopaminergic neurons, between Korean patients with 188 PD and 321 lung cancer patients. There were no significant differences in the tested single-nucleotide polymorphisms (SNPs) between patients with PD and lung cancer; however, one haplotype was significantly different in comparisons between the two diseases. These results suggest that VEGF genetic polymorphisms might help understand the low incidence of lung cancer in the patients with PD.

Promoter polymorphisms of the vascular endothelial growth factor gene is associated with an osteonecrosis of the femoral head in the Korean population

OBJECTIVE

Disruption of the vascular supply to the bone and subsequent hypoxia has been implicated in the pathogenesis of osteonecrosis of the femoral head (ONFH). Vascular endothelial growth factor (VEGF), a major inducer of angiogenesis, has been correlated with several pathological conditions, from inflammation to ischemic processes. A number of polymorphisms in the VEGF gene have been described as being associated with several diseases, such as diabetic retinopathy, prostate cancer and breast cancer. The aim of this study was to evaluate the association of VEGF gene polymorphisms with ONFH in a case--control study.

METHODS

Three polymorphisms (-2578C>A, -634G>C and +936C>T) in VEGF were genotyped in 317 ONFH patients and 497 control subjects, using the TaqMan 5' allelic discrimination assay. We performed the association analysis of genotyped single nucleotide polymorphisms (SNPs) and haplotypes with ONFH.

RESULTS

The -634G>C genotype was significantly associated with an increased risk for ONFH in dominant model with odds ratio (OR) of 1.47, 95% confidence intervals (CIs) 1.08-2.01 with P value 0.015. Further analysis stratified by sex showed that the -634G>C genotype was also significantly associated with a high risk for male patients considering the dominant model with OR of 1.60, 95% CI 1.13-2.26 with P value 0.008. Haplotype association analysis did not provide a further delineation of the risk allele.

CONCLUSION

Our study is, to our knowledge, the first report that shows the -634G>C polymorphism in the VEGF promoter was associated with an increased susceptibility of ONFH in the Korean population.

VEGF as a potential target for therapeutic intervention in depression

Antidepressants are among the most widely prescribed drugs, however the mechanism underlying their therapeutic efficacy is not known. Neurotrophic factors represent a promising class of targets for antidepressant treatments. We recently characterized a role for vascular endothelial growth factor (VEGF) in cellular and behavioral antidepressant responses. VEGF is a potent mitogen and survival factor for endothelial cells (ECs) and neurons, and modulator of synaptic transmission. Because VEGF has been implicated in a variety of diseases, understanding the molecular and cellular specificity of antidepressant-induced VEGF will be crucial to determine its potential as a therapeutic target in depression.

Strategic approaches to developing drug treatments for ALS

Significant progress in understanding the cellular mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS) has not been matched with the development of therapeutic strategies to prevent disease progression. The multiple potential causes and relative rarity of the disease are two significant factors that make drug development and assessment in clinical trials extremely difficult. We review recent progress in promoting therapeutics into clinical trials and highlight the value of moderate throughput screening for the acceleration and improvement of drug design.

Gene expression and association analysis of vascular endothelial growth factor in major depressive disorder

Vascular endothelial growth factor (VEGF) has been implicated in neuronal survival, neuroprotection, regeneration, growth, differentiation, and axonal outgrowth, which are known to be involved in the pathophysiology of major depressive disorder (MDD). Recently, the VEGF mRNA expression in the peripheral leukocytes from Alzheimer's disease or cardiovascular disease was reported to be changed. We hypothesized that the expression of the VEGF mRNA in the peripheral leukocytes may be a good candidate for the biological marker for MDD. Thirty two patients with MDD and age- and sex-matched control subjects were included in this expression study. The VEGF mRNA levels in the peripheral leukocytes from drug-naive MDD patients were significantly higher than those from the control subjects and the magnitude of the decrease of VEGF mRNA after 8-week treatment significantly correlated with clinical improvement. Then, we genotyped two single nucleotide polymorphic markers of VEGF gene, which were reported to be associated with amyotrophic lateral sclerosis and Alzheimer's disease, in patients with MDD and control subjects (n=154, each). We did not find any significant association between these markers and MDD or its clinical subtypes. Our investigation indicates that the higher expression levels of VEGF mRNA in the peripheral leukocytes are associated with the depressive state and their recovery after treatment may be associated with the clinical improvement.

VEGF at the neurovascular interface: therapeutic implications for motor neuron disease

VEGF was discovered almost 25 years ago, and its angiogenic activity has been extensively studied ever since. Accumulating evidence indicates, however, that VEGF also has direct effects on neuronal cells. VEGF exerts neuroprotective effects on various cultured neurons of the central nervous system. In vivo, VEGF controls the correct migration of facial branchiomotor neurons in the developing hindbrain and stimulates the proliferation of neural stem cells in enriched environments and after cerebral ischemia. Transgenic mice expressing reduced levels of VEGF develop late-onset motor neuron degeneration, reminiscent of amyotrophic lateral sclerosis (ALS), whereas reduced levels of VEGF have been implicated in a polyglutamine-induced model of motor neuron degeneration. Recent data further reveal that intracerebroventricular delivery of recombinant VEGF protein delays disease onset and prolongs survival of ALS rats, whereas intramuscular administration of a VEGF-expressing lentiviral vector increases the life expectancy of ALS mice by as much as 30%. Deciphering the precise role of VEGF at the neurovascular interface promises to uncover new insights into the development and pathology of the nervous system, helpful to design novel strategies to treat (motor) neurodegenerative disorders.

Contraindications of VEGF-based therapeutic angiogenesis: Effects on macrophage density and histology of normal and ischemic brains

Therapeutic angiogenesis by vascular endothelial growth factor (VEGF) is advocated as a promising treatment strategy for brain ischemic stroke. However, data in the literature demonstrating the benefit of therapeutic angiogenesis are contradictory. In this paper, we describe the effects of non-angiogenic and angiogenic doses of VEGF165 on macrophage density and histology of normal and ischemic brains of adult rats. VEGF165 was administered intra-arterially for 7 days following temporary occlusion of the middle cerebral artery. In contrast to ischemic brains treated with non-angiogenic doses of VEGF165 which showed preserved neuropil and reduced numbers of macrophages, ischemic brains treated by an angiogenic dose showed phagocytized neuropil and high macrophage density. Though neither non-angiogenic nor angiogenic doses caused macrophage infiltration in normal brains, damage of the brain matrix occurred with the angiogenic dose. These results suggest an angiogenic dose of VEGF165 injures the nervous tissue rather than promote recovery. Angiogenesis by VEGF monotherapy for ischemic stroke should be viewed with caution, or avoided. Since our data show intravascular administration of VEGF165 does not cause macrophage inflammation, in contrast to reports in the literature whereby VEGF165 was applied directly to the brain, our findings also indicate the relationships between VEGF, angiogenesis, and macrophage inflammation are governed by the route VEGF is administered to the brain.

Gene-based treatment of motor neuron diseases

Motor neuron diseases (MND), such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), are progressive neurodegenerative diseases that share the common characteristic of upper and/or lower motor neuron degeneration. Therapeutic strategies for MND are designed to confer neuroprotection, using trophic factors, anti-apoptotic proteins, as well as antioxidants and anti-excitotoxicity agents. Although a large number of therapeutic clinical trials have been attempted, none has been shown satisfactory for MND at this time. A variety of strategies have emerged for motor neuron gene transfer. Application of these approaches has yielded therapeutic results in cell culture and animal models, including the SOD1 models of ALS. In this study we describe the gene-based treatment of MND in general, examining the potential viral vector candidates, gene delivery strategies, and main therapeutic approaches currently attempted. Finally, we discuss future directions and potential strategies for more effective motor neuron gene delivery and clinical translation.

Angiogenesis: update 2005

Angiogenesis has critical roles in normal vascular development and in important pathologies including cancer, wound healing and inflammation. This brief article will review the angiogenic response induced by the vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) family of proteins and particularly VEGF-A, thought to be the single most important angiogenic factor. It will also review the steps and mechanisms by which VEGF-A induces the formation of new blood vessels and will provide an initial classification of the abnormal blood vessels that form in pathological angiogenesis. Finally, it will touch on the exciting relationships that are emerging between angiogenesis and the hemostatic and nervous systems.

Prosurvival and Prodeath Effects of Hypoxia-inducible Factor-1α Stabilization in a Murine Hippocampal Cell Line

Hypoxia-inducible factor-1 (HIF-1) is a transcriptional activator involved in adaptation to hypoxic stress. Previous studies from our laboratory demonstrated that pharmacological activators of HIF-1 (e.g. deferoxamine, cobalt chloride) could also protect cultured primary neurons or an immortalized hippocampal neuroblast line (HT22) from oxidative stress-induced death. However, whether HIF-1 activation is sufficient to abrogate neuronal death resulting from oxidative stress or other hypoxia-independent death inducers remains unclear. To address this question we utilized a HIF-1alpha fusion protein that partially lacks the domain required for oxygen-dependent degradation of HIF-1alpha and that has a VP16 transcriptional activation domain from herpes simplex virus. HT22 cells were infected with a retrovirus encoding either the HIF-1alpha-VP16 fusion protein or the activation domain of the VP16 protein alone as a control. Expression of HIF-1alpha-VP16, but not VP16 alone, increased luciferase activity driven by a canonical hypoxia response element, increased mRNA of established HIF-1 target genes, and increased activity of one of these HIF-1 target genes. Unexpectedly, enhanced HIF-1 activity in HT22 cells enhanced sensitivity to oxidative death induced by glutathione depletion. Accordingly, suppression of HIF-1alpha expression using RNA interference prevented oxidative death. By contrast, HIF-1alpha-VP16-expressing HT22 cells were more resistant to DNA damage (induced by camptothecin) or endoplasmic reticulum stress (induced by thapsigargin and tunicamycin) than were VP16-expressing cells, and suppression of HIF-1alpha expression using RNA interference rendered HT22 cells more sensitive to death induced by DNA damage or endoplasmic reticulum stress. Together, these data demonstrate that HIF-1 can mediate prodeath or prosurvival responses in the same cell type depending on the injury stimulus.

Vascular endothelial growth factor gene variability is associated with increased risk for AD

Converging evidence points to a pivotal role of vascular endothelial growth factor (VEGF) in neuronal protection and a lack of its activity in neurodegenerative disorders. To investigate this possible association, we screened the VEGF gene promoter for various well-known single-nucleotide polymorphisms in a series of 249 consecutively recruited Italian patients with sporadic Alzheimer's disease (AD). Genetic analysis indicated different distributions of two single-nucleotide polymorphisms in the AD population compared with healthy control subjects. In particular, the frequencies of -2578A/A and -1198C/T genotypes were significantly greater in AD patients than in control subjects (23.7 vs 14.7% and 2.8 vs 0%, respectively). The -2578A/A genotype was associated with an increased risk for disease, independently of apolipoprotein E genotype. The risk was significantly increased with respect to various VEGF genotype combinations. In contrast, no difference in serum VEGF levels was detected comparing 96 patients and 49 control subjects. These findings suggest that polymorphisms within the promoter region of the VEGF gene confer greater risk for AD, probably by reducing its neuroprotective effect, and confirm the biological role of VEGF in neurodegenerative processes.

VEGF: necessary to prevent motoneuron degeneration, sufficient to treat ALS?

Since Charcot recognized the devastating disorder amyotrophic lateral sclerosis (ALS) in 1874, many theories have been proposed to explain its pathogenesis, but it remains as deadly and incurable as ever. Three years ago it was reported that reduced levels of vascular endothelial growth factor (VEGF) caused ALS-like motoneuron degeneration in mice. Recent evidence indicates that insufficient VEGF is also a risk factor for ALS in humans. Although VEGF was once considered to be only a specific angiogenic factor, emerging evidence indicates that it also displays important neuroprotective activity. These insights have primed widespread interest in developing VEGF-based therapies for (moto)neuron degenerative disorders, raising new hope for the treatment of ALS and other neurodegenerative diseases.