Novel Biomarkers for Limb Girdle Muscular Dystrophy (LGMD).

OBJECTIVE: To identify novel biomarkers as an alternative diagnostic tool for limb girdle muscular dystrophy (LGMD). BACKGROUND: LGMD encompasses a group of muscular dystrophies characterized by proximal muscles weakness, elevated CK levels and dystrophic findings on muscle biopsy. Heterozygous CAPN3 mutations are associated with autosomal dominant LGMD-4, while biallelic mutations can cause autosomal recessive LGMD-1. Diagnosis is currently often based on invasive methods requiring muscle biopsy or blood tests. In most cases Western blotting (WB) analysis from muscle biopsy is essential for a diagnosis, as muscle samples are currently the only known tissues to express the full-length CAPN3 isoform. METHODS: We analyzed CAPN3 in a cohort including 60 LGMD patients. Selected patients underwent a complete neurological examination, electromyography, muscle biopsy, and skin biopsies for primary fibroblasts isolation. The amount of CAPN3 was evaluated by WB analysis in muscle and skin tissues. The total RNA isolated from muscle, fibroblast and urine was processed, and cDNA was used for qualitative analysis. The expression of CAPN3 was investigated by qRT-PCR. The CAPN3 3D structure has been visualized and analyzed using PyMOL. RESULTS: Among our patients, seven different CAPN3 mutations were detected, of which two were novel. After sequencing CAPN3 transcripts from fibroblast and urine, we detected different CAPN3 isoforms surprisingly including the full-length transcript. We found comparable protein levels from fibroblasts and muscle tissue; in particular, patients harboring a novel CAPN3 mutation showed a 30% reduction in protein compared to controls from both tissues. CONCLUSIONS: Our findings showed for the first time the presence of the CAPN3 full-length transcript in urine and skin samples. Moreover, we demonstrated surprisingly comparable CAPN3 protein levels between muscle and skin samples, thus allowing us to hypothesize the use of skin biopsy and probably of urine samples as an alternative less invasive method to assess the amount of CAPN3 when molecular diagnosis turns out to be inconclusive.

Fibroblast growth factor 21 and grow differentiation factor 15 are sensitive biomarkers of mitochondrial diseases due to mitochondrial transfer-RNA mutations and mitochondrial DNA deletions.

BACKGROUND: Diagnosis of mitochondrial diseases (MDs) is challenging, since they are multisystemic disorders, characterized by a heterogeneous symptomatology. Recently, an increase in serum levels of fibroblast growth factor 21 (FGF21) and growth differentiation factor 15 (GDF15) has been found in the majority of patients with MDs compared with healthy controls. On the other hand, the finding of low FGF21 and GDF15 levels in some patients with MDs suggests that different types of respiratory chain defects may lead to different profiles of these two proteins. OBJECTIVE: In this study, we aimed to validate the diagnostic reliability of FGF21 and GDF15 assays in MDs and to evaluate a possible correlation between serum levels of the two biomarkers with genotype of MD patients. Serum FGF21 and GDF15 levels were measured by a quantitative ELISA. RESULTS: Our results showed increased serum FGF21 and GDF15 levels in MD patients; however, GDF15 measurement seems to be more sensitive and specific for screening tests for MD than FGF21. Moreover, we showed a positive correlation with both FGF21 and GDF15 levels and the number of COX-negative fibers. CONCLUSION: Finally, we also demonstrated that the increase of FGF21 and GDF15 was related to MDs caused by mitochondrial translation defects, and multiple and single mtDNA deletions, but not to MDs due to mutations in the respiratory chain subunits.

HTRA1 expression profile and activity on TGF-ß signaling in HTRA1 mutation carriers.

High temperature requirement A1 (HTRA1) is a serine protease playing a modulatory role in various cell processes, particularly in the regulation of transforming growth factor-ß (TGF-ß) signaling. A deleterious role in late-onset cerebral small vessel diseases (CSVDs) of heterozygous HTRA1 mutations, otherwise causative in homozygosity of cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy, was recently suggested. However, the pathomechanism of these heterozygous mutations is still undefined. Our aim is to evaluate the expression profile and activity of HTRA1 on TGF-ß signaling in fibroblasts from four subjects carrying the HTRA1 heterozygous mutations-p.E42Dfs*173, p.A321T, p.G295R, and p.Q151K. We found a 50% reduction of HTRA1 expression in HTRA1 mutation carriers compared to the control. Moreover, we showed no changes in TGF-ß signaling pathway downstream intermediate, Phospho Smad2/3. However, we found overexpression of genes involved in the extracellular matrix formation in two heterozygous HTRA1 carriers. Our results suggest that each heterozygous HTRA1 missense mutation displays a different and peculiar HTRA1 expression pattern and that CSVD phenotype may also result from 50% of HTRA1 expression.

Primary cilium alterations and expression changes of Patched1 proteins in niemann-pick type C disease.

Niemann-Pick type C disease (NPC) is a disorder characterized by abnormal intracellular accumulation of unesterified cholesterol and glycolipids. Two distinct disease-causing genes have been isolated, NPC1 and NPC2. The NPC1 protein is involved in the sorting and recycling of cholesterol and glycosphingolipids in the late endosomal/lysosomal system. It has extensive homology with the Patched1 (Ptc1) receptor, a transmembrane protein localized in the primary cilium, and involved in the Hedgehog signaling (Shh) pathway. We assessed the presence of NPC1 and Ptc1 proteins and evaluated the relative distribution and morphology of primary cilia in fibroblasts from five NPC1 patients and controls, and in normal fibroblasts treated with 3-ß-[2-(diethylamino)ethoxy]androst-5-en-17-one (U18666A), a cholesterol transport-inhibiting drug that is widely used to mimic NPC. Immunofluorescence and western blot analyses showed a significant decrease in expression of NPC1 and Ptc1 in NPC1 fibroblasts, while they were normally expressed in U18666A-treated fibroblasts. Moreover, fibroblasts from NPC1 patients and U18666A-treated cells showed a lower percentage distribution of primary cilia and a significant reduction in median cilia length with respect to controls. These are the first results demonstrating altered cytoplasmic expression of Ptc1 and reduced number and length of primary cilia, where Ptc1 is located, in fibroblasts from NPC1 patients. We suggest that the alterations in Ptc1 expression in cells from NPC1 patients are closely related to NPC1 expression deficit, while the primary cilia alterations observed in NPC1 and U18666A-treated fibroblasts may represent a secondary event derived from a defective metabolic pathway.

Primary familial brain calcification with a novel SLC20A2 mutation: Analysis of PiT-2 expression and localization.

Primary familial brain calcification (PFBC) is an autosomal dominant rare disorder characterized by bilateral and symmetric brain calcifications, and neuropsychiatric manifestations. Four genes have been linked to PFBC: SLC20A2, PDGFRB, PDGFB, and XPR1. In this study, we report molecular and clinical data of a PFBC patient carrying a novel SLC20A2 mutation and we investigate the impact of the mutation on PiT-2 expression and function. Sanger sequencing of SLC20A2, PDGFRB, PDGFB, XPR1 led to the identification of a novel duplication of twelve nucleotides (c.1876_1887dup/ p.Trp626_Thr629dup) in SLC20A2 gene. SLC20A2 encodes for a cell membrane transporter (PiT-2) involved in maintenance of inorganic phosphate homeostasis. We performed an analysis of expression and functionality of PiT-2 protein in patient primary cultured fibroblasts. In patient fibroblasts, the mutation does not affect PiT-2 expression but alter sub-cellular localization. The Pi-uptake assay revealed a less Pi depletion in patient than in control fibroblasts, suggesting that SLC20A2 duplication may impair Pi internalization. This is the first study reporting sub-cellular expression analysis of mutant PiT-2 in primary cultured fibroblasts from a PFBC patient, showing that p.Trp626_Thr629dup in SLC20A2 alters PiT-2 sub-cellular localization and reduces Pi-uptake, leading to onset of PFBC in our patient.

Oxidative stress-induced apoptosis in peripheral blood lymphocytes from patients with POLG-related disorders.

BACKGROUND: POLG-related disorders are a group of heterogeneous diseases characterized by an overlapping clinical presentations and associated with mutations in the POLG gene. POLG codes for the catalytic subunit of mitochondrial polymerase gamma (POLG), essential for mitochondrial DNA (mtDNA) replication and repair. Studies on mutator POLG mice showed an increase in oxidative stress and apoptosis. In this regard we analysed the involvement of POLG mutations in the apoptotic regulation, evaluating apoptosis in peripheral blood lymphocytes (PBLs) from patients with POLG-related diseases. METHODS: Cells were cultured under basal conditions and with 2-deoxy-d-ribose (dRib), a reducing sugar that induces apoptosis by oxidative stress. Apoptosis rate was assessed by flow cytometry. Phosphatidylserine translocation, mitochondrial membrane depolarization and caspase 3 activation were also analysed. RESULTS: Our data showed higher percentages of apoptosis after dRib treatment in patients with POLG mutations than in controls, while under basal culture conditions, apoptosis levels were similar in the two groups. CONCLUSIONS: Cells with POLG mutations are more sensitive than control cells to oxidative stress-induced apoptosis, confirming that mtDNA mutations may have a role in mitochondrial apoptosis pathway. We also suggest that redox state homeostasis may play a crucial role in phenotypic expression of POLG-related diseases.

Analysis of opa1 isoforms expression and apoptosis regulation in autosomal dominant optic atrophy (ADOA) patients with mutations in the opa1 gene.

Autosomal dominant optic atrophy (ADOA) is a hereditary optic neuropathy characterized by bilateral symmetrical visual loss, decrease in retinal ganglion cells and a loss of myelin within the optic nerve. ADOA is associated to mutations in Optic atrophy 1 gene (OPA1), which encodes a mitochondrial protein involved in cristae remodeling, maintenance of mitochondrial membrane integrity, mitochondrial fusion and apoptosis regulation. We thus evaluated the rate of apoptosis and the expression levels of OPA1 isoforms in ADOA and control cells. Peripheral blood lymphocytes from eight patients with OPA1 mutation and age matched controls were cultivated both in basal conditions or with 2-deoxy-D-ribose, a reducing sugar that induces apoptosis through oxidative stress. Apoptosis was analyzed by flow cytometry, phosphatidylserine translocation, mitochondrial membrane depolarization and caspase 3 activation. We also analyzed the expression levels of OPA1 isoforms in ADOA and control cells cultured with and without 2-deoxy-D-ribose. We showed an increased percentage of apoptotic cells in ADOA patients compared to controls, both in basal culture conditions and after 2-deoxy-D-ribose treatment. This suggested a great susceptibility of ADOA cells to oxidative stress and a strong correlation between OPA1 protein dysfunctions and morphological-functional alterations to mitochondria. Moreover OPA1 protein expression was significantly decreased in lymphocytes from the ADOA patients after 2-deoxy-D-ribose treatment, implying a great sensitivity of the mutated protein to free radical damage. Concluding, we could confirm that oxidative stress-induced apoptosis may play a key role in the pathophysiological process bringing to retinal ganglion cells degeneration in ADOA.

Apoptosis and oxidative stress in neurodegenerative diseases.

Neurodegenerative disorders affect almost 30 million individuals leading to disability and death. These disorders are characterized by pathological changes in disease-specific areas of the brain and degeneration of distinct neuron subsets. Despite the differences in clinical manifestations and neuronal vulnerability, the pathological processes appear similar, suggesting common neurodegenerative pathways. Apoptosis seems to play a key role in the progression of several neurologic disorders like Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis as demonstrated by studies on animal models and cell lines. On the other hand, research on human brains reported contradictory results. However, many dying neurons have been detected in brains of patients with neurodegenerative diseases, and these conditions are often associated with significant cell loss accompanied by typical morphological features of apoptosis such as chromatin condensation, DNA fragmentation, and activation of cysteine-proteases, caspases. Cell death and neurodegenerative conditions have been linked to oxidative stress and imbalance between generation of free radicals and antioxidant defenses. Multiple sclerosis, stroke, and neurodegenerative diseases have been associated with reactive oxygen species and nitric oxide. Here we present an overview of the involvement of neuronal apoptosis and oxidative stress in the most important neurodegenerative diseases, mainly focusing the attention on several genetic disorders, discussing the interaction between primary genetic abnormalities and the apoptotic pathways.

Hereditary diffuse leukoencephalopathy with axonal spheroids: three patients with stroke-like presentation carrying new mutations in the CSF1R gene.

Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) is an autosomal dominant disorder characterized by white matter neurodegeneration, progressive cognitive decline, and motor symptoms. Histologically, it is characterized by axonal swellings ("spheroids"). To date, over 20 different mutations affecting the tyrosine kinase domain of the protein have been identified in the colony stimulating factor 1 receptor (CSF1R) gene. Our goal is to describe three unrelated Italian patients affected by HDLS and carrying new CSF1R mutations, thus expanding the mutational spectrum and phenotypic presentation. CSF1R gene analysis was performed in 15 patients (age range 25-83 years) with undefined leukoencephalopathy and progressive cognitive decline. In three patients (two males and one female, aged 58, 37, and 48 years, respectively), new heterozygous missense mutations affecting the protein tyrosine kinase domain of the CSF1R gene were detected. In all of these patients, behavioural and cognitive changes were preceded by an ischemic stroke-like episode. A positive family history was present in only one case.

Effects of cerebrolysin administration on oxidative stress-induced apoptosis in lymphocytes from CADASIL patients.

Cerebrolysin (Cere) is a peptidergic nootropic drug with neurotrophic properties which has been used to treat dementia and sequelae of stroke. Use of Cere prevents nuclear structural changes typical of apoptosis and significantly reduces the number of apoptotic cells after several apoptotic stimuli. Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a hereditary disease caused by mutations of the Notch3 gene encoding the Notch3 protein. Notch3 is involved in the regulation of apoptosis, modulating Fas-Ligand (Fas-L)- induced apoptosis. The aim of this study was to evaluate the in vitro protective effects of Cere against oxidative stress-induced apoptosis in cells from CADASIL patients. We used peripheral blood lymphocytes (PBLs) from 15 CADASIL patients (age range 34-70 years); 2-deoxy-D-ribose (dRib), a highly reducing sugar, was used as paradigm pro-apoptotic stimulus. Apoptosis was analyzed by flow cytometry and fluorescence microscopy. Administration of Cere to PBLs from CADASIL patients cultured under standard conditions had no effect on the percentage of apoptotic cells. Administration of Cere to PBLs cultured with dRib caused a significant decrease in apoptosis after 48 h of culture in only 5 patients, whereas in the other 10 patients, Cere treatment was not associated with any significant difference in the percentage of apoptosis. This result showed a protective effect of Cere against oxidative stress-induced apoptosis only in 30 % of the CADASIL patients, suggesting that the Notch3 gene probably does not influence the anti-apoptotic properties of Cere in vitro.

Cerebrolysin administration reduces oxidative stress-induced apoptosis in lymphocytes from healthy individuals.

Cerebrolysin is the only drug available for clinical use containing active fragments of some important neurotrophic factors obtained from purified porcine brain proteins, which has long been used for the treatment of dementia and stroke sequels. Cerebrolysin has growth factor-like activities and promotes neuronal survival and sprouting, however, its molecular mechanism still needs to be determined. It has been shown that Cerebrolysin may interact with proteolytic pathways linked to apoptosis. Administration of Cerebrolysin significantly reduces the number of apoptotic neurons after glutamate exposure. Furthermore, it has been reported that Cerebrolysin inhibits free radicals formation and lipid peroxidation. In vitro we evaluated the protective effects of Cerebrolysin towards spontaneous and induced apoptotic death in cells from healthy individuals. Peripheral blood lymphocytes (PBLs) from 10 individuals were used as cell model; 2-deoxy-D-ribose (dRib), a highly reducing sugar, was used as paradigm pro-apoptotic stimulus. Apoptosis was analysed using flow cytometry and fluorescence microscopy. Our results showed that Cerebrolysin significantly reduced the number of apoptotic PBLs after dRib treatment, although it had no significative effects on cells cultured in standard conditions. Our work showed a protective effect of Cerebrolysin on oxidative stress-induced apoptosis and suggested that PBLs can be used as an easy obtainable and handy cell model to verify Cerebrolysin effects in neurodegenerative pathologies.

Mitochondria, oxidative stress and neurodegeneration.

Mitochondria are involved in ATP supply to cells through oxidative phosphorylation (OXPHOS), synthesis of key molecules and response to oxidative stress, as well as in apoptosis. They contain many redox enzymes and naturally occurring inefficiencies of oxidative phosphorylation generate reactive oxygen species (ROS). CNS functions depend heavily on efficient mitochondrial function, since brain tissue has a high energy demand. Mutations in mitochondrial DNA (mtDNA), generation and presence of ROS and environmental factors may contribute to energy failure and lead to neurodegenerative diseases. Many rare metabolic disorders have been associated with mitochondrial dysfunction. More than 300 pathogenic mtDNA mutations involve proteins that regulate OXPHOS and mitochondrial structural integrity, and have also been described in neurodegenerative diseases with autosomal inheritance. Mitochondria may have an important role in ageing-related neurodegenerative disorders like Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). In primary mitochondrial and neurodegenerative disorders, there is strong evidence that mitochondrial dysfunction occurs early and has a primary role in pathogenesis. In the present review, we discuss several mitochondrial diseases as models of neurodegeneration.

Altered apoptosis regulation in Kufor-Rakeb syndrome patients with mutations in the ATP13A2 gene.

ATP13A2 gene encodes for a protein of the group 5 P-type ATPase family. ATP13A2 mutations are responsible for Kufor-Rakeb syndrome (KRS), a rare autosomal recessive juvenile parkinsonism characterized by the subacute onset of extrapyramidal, pyramidal and cognitive dysfunction with secondary nonresponsiveness to levodopa. FBXO7 protein is an F-box-containing protein. Recessive FBXO7 mutations are responsible for PARK15, a rare juvenile parkinsonism characterized by progressive neurodegeneration with extrapyramidal and pyramidal system involvement. Our aim was to evaluate apoptosis in cells from two KRS siblings carrying a homozygous ATP13A2 mutation and a heterozygous FBXO7 mutation. We also analysed apoptosis in the patients' healthy parents. Peripheral blood lymphocytes from the KRS patients and parents were exposed to 2-deoxy-D-ribose; apoptosis was analysed by flow cytometry and fluorescence microscopy. Apoptosis was much higher in lymphocytes from the KRS patients and parents than in controls, both in standard conditions and after induction with a pro-apoptotic stimulus. The lack of correlation between increased apoptosis and the presence of the mutated FBXO7 gene rules out the involvement of FBXO7 in apoptosis regulation. The altered apoptotic pattern of subjects with mutated ATP13A2 suggests a correlation between apoptosis alteration and the mutated ATP13A2 protein. We hypothesize that ATP13A2 mutations may compromise protein function, disrupting cell cation balance and rendering cells prone to apoptosis. However, the deregulation of apoptosis in KRS patients displaying different disease severity suggested that the altered apoptotic pathway probably does not have a pathogenetic role in KRS by itself.

Human peripheral blood lymphocytes and fibroblasts as Notch3 expression models.

Notch3 is a single pass transmembrane protein belonging to the Notch receptor family. Notch proteins are involved in a very conserved signaling system (Notch signaling) with a broad spectrum of functions, from cell proliferation and differentiation to apoptosis. Mutations in Notch3 gene are linked to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a disorder characterized by stroke and dementia in young adults. Studies evaluating Notch3 expression in human differentiated cells and adult tissues have shown high Notch3 levels only in vascular smooth muscle cells (VSMC). However, it has been hypothesized that Notch3 is ubiquitously expressed in adult human tissues. Our aim was to evaluate Notch3 expression in human peripheral blood lymphocytes (PBLs) and fibroblasts from normal healthy subjects. In both cell types, we examined the expression of Notch3 by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, we assessed Notch3 protein expression by Western blot analysis. RT-PCR and qRT-PCR analysis showed the presence of Notch3 mRNA in both cell types. Western blot analysis confirmed Notch3 protein expression in PBLs and fibroblasts though showing different profiles. Our data support the expression of Notch3 in adult human cell types, and suggests that PBLs and fibroblasts could provide readily available cells for the study of the role of Notch3 expression in the pathogenetic mechanisms leading to different human disease.

Oxidative stress-induced apoptosis in two patients with Alagille syndrome.

Alagille syndrome (AGS) is an autosomal dominant disorder characterized by cholestasis, cardiac, skeletal and ocular abnormalities. Increasing importance is being given to vascular and central nervous system impairment. AGS is in most cases caused by heterozygous mutations in the Jagged-1 (JAG1) gene encoding a cell-surface ligand of the Notch receptors. The interaction between Notch1 and JAG1 induces proliferation and inhibits apoptosis. We evaluated the role of apoptosis in AGS patients carrying a truncating mutation in exon 7 of JAG1. Peripheral blood lymphocytes (PBLs) from two patients were exposed to 2-deoxy-d-ribose (dRib). Apoptosis was analyzed by flow cytometry, fluorescence microscopy and Western blotting. PBLs from patients showed a significantly higher percentage of apoptosis than controls both in standard culture conditions and after dRib treatment, however we demonstrated a lack of caspase-8 activation in those cells. Our results confirm that JAG1 may play a role in apoptosis regulation. In particular, truncating mutations in JAG1 could lead to Notch signaling inhibition and determine a deregulation of survival and proliferation, favoring apoptosis. Moreover, the lack of caspase-8 activation in AGS patients indicates a possible selective impairment of caspase-8 cleavage suggesting that JAG1 plays a specific role in the regulation of caspase-8 activation.

CSF Biomarkers Profile in CADASIL-A Model of Pure Vascular Dementia: Usefulness in Differential Diagnosis in the Dementia Disorder.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is considered a model of pure vascular dementia (VD) because it occurs in young adults unlikely to have concomitant age and Alzheimer's Disease-(AD-) related pathology. CSF levels of ß-amyloid 1-42 (Aß42), total tau protein (t-tau), and phosphorylated tau-protein (p-tau), well accepted biomarkers of AD, were evaluated in 10 CADASIL patients, 22 AD patients, and 17 healthy age-matched subjects. Innotest ß-amyloid 1-42, Innotest hTAU-Ag, and Innotest Phospho-tau 181p sandwich enzyme-linked immunoassay were used to determine CSF biomarkers levels. A case-control statistical analysis was carried out. CSF Aß42 levels were significantly lower in CADASIL patients and considerable overlap with AD whereas t-tau and p-tau levels were normal and significantly different with respect to AD. A significant altered CSF biomarkers profile in a pure VD supports the use of CSF Aß42, t-tau, and p-tau levels in the differential diagnosis of VD and AD.

Apoptosis in CADASIL: an in vitro study of lymphocytes and fibroblasts from a cohort of Italian patients.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary disease affecting vascular smooth muscle cells of nearly all tissues. Clinical manifestations mainly concern the central nervous system with repeated TIA/stroke, migraine, psychiatric disturbances, and cognitive decline. Minor findings have been reported in muscle, nerve, and skin. CADASIL is due to NOTCH3 gene mutations. This gene has been identified as an up-regulator of c-FLIP, an inhibitor of Fas-ligand-induced apoptosis. The aim of this study was to assess the involvement of oxidative stress-induced apoptosis in cells from 16 Italian CADASIL patients. Peripheral blood lymphocytes (PBLs) and fibroblasts from CADASIL patients were exposed to 2-deoxy-D-ribose (dRib), which induces apoptosis by oxidative stress. Apoptosis was analyzed by flow cytometry, agarose gel electrophoresis and fluorescence microscopy for caspase-3 activation, phosphatidylserine exposure and mitochondrial membrane depolarization. PBLs and fibroblasts from CADASIL patients showed a significantly higher response to dRib-induced apoptosis than those of controls. PBLs from CADASIL patients also showed a significantly higher percentage of apoptotic cells than PBLs from controls, even when cultured without dRib. The greater susceptibility of PBLs and fibroblasts from CADASIL patients to dRib-induced apoptosis suggests that NOTCH3 mutations are an important apoptotic trigger. Since PBLs from patients showed higher levels of apoptosis even in the absence of an apoptotic stimulus, cells from CADASIL patients appear to be physiologically prone to apoptotic cell death.

Oxidative-stress-induced apoptosis in PBLs of two patients with Parkinson disease secondary to alpha-synuclein mutation.

Alpha-synuclein has been implicated in the pathology of certain neurodegenerative diseases, including Parkinson disease (PD). Although the precise physiological and pathological role of alpha-synuclein is unclear, overexpression of the protein or its mutants may reduce cell viability. In this study we evaluated the apoptotic response to oxidative stress induced by 2-deoxy-d-ribose (dRib) in peripheral blood lymphocytes (PBLs) of two siblings with Parkinson disease secondary to A53T alpha-synuclein mutation. PBLs exposed to oxidative stress showed a higher percentage of apoptotic cells in PD patients than in controls. However in cells of PD patients, the increase of apoptotic response was lower than in controls, suggesting that cells of PD patients have greater "resistance" to oxidative stress. We conclude that other environmental agents could play a key role in inducing programmed cell death in cells of PD patients with mutant alpha-synuclein.

Psychosine-induced apoptosis and cytokine activation in immune peripheral cells of Krabbe patients.

Globoid cell leukodystrophy or Krabbe disease (KD), is a hereditary disorder caused by galactosylceramidase deficiency. Progressive accumulation of psychosine is considered to be the critical pathogenetic mechanism of cell death in the Krabbe brain. Psychosine mechanism of action has not been fully elucidated. It seems to induce apoptosis in oligodendrocytes through a mitochondrial pathway and to up-regulate inflammatory cytokines production resulting in oligodendrocyte loss. Our aim was to evaluate the role of psychosine in apoptotic cell death and inflammatory response in a group of patients affected by KD using peripheral blood lymphocytes (PBLs) and peripheral blood mononuclear cells (PBMCs) as a cellular model. PBLs from KP and healthy controls were exposed to 20 microM psychosine and analysed by flow cytometry, agarose gel electrophoresis and fluorescence microscopy. Our results showed that psychosine induces apoptosis in PBLs through a mitochondrial pathway, but the apoptotic response was quite low especially KP. The role of psychosine in the up-regulation of cytokines (TNFalpha, IL8 and MCP1) has been evaluated by ELISA in PBMCs from KP and controls after stimulation with LPS and phytohemagglutinin. Both in basal condition and after LPS stimulation, cells from KP showed a significant increase in TNF-alpha production, reduced MCP1 levels and no modification in IL8. These results indicate that lymphomonocytes from KP had a basal proinflammatory pattern that was amplified by psychosine. In conclusion, the reduced apoptotic response and the atypical cytokine production observed in our experiments, suggest an involvement of inflammatory pattern in immune peripheral cells of KP.

Cerebrospinal fluid tau, A beta, and phosphorylated tau protein for the diagnosis of Alzheimer's disease.

The diagnosis of AD is still largely based on exclusion criteria of secondary causes and other forms of dementia with similar clinical pictures, than the diagnostic accuracy of AD is low. Improved methods of early diagnosis are needed, particularly because drugs treatment is more effective in the early stages of the disease. Recent research focused the attention to biochemical diagnostic markers (biomarkers) and according to the proposal of a consensus group on biomarkers, three candidate CSF markers reflecting the pathological AD processes, have recently been identified: total tau protein (t-tau), amyloid beta(1-42) protein (A beta42), and tau protein phosphorylated at AD-specific epitopes (p-tau). Several articles report reduced CSF levels of A beta42 and increased CSF levels of t-tau and p-tau in AD; the sensitivity and specificity of these data are able for discrimination of AD patients from controls. However, the specificity for other dementias is low. According to the literature analysis reported in the present review, we can conclude that the combination of the CSF markers and their ratios may significantly increase the specificity and the accuracy of AD diagnosis.