Detection and imaging of non-contractile inclusions and sarcomeric anomalies in skeletal muscle by second harmonic generation combined with two-photon excited fluorescence.

The large size of the multinucleated muscle fibers of skeletal muscle makes their examination for structural and pathological defects a challenge. Sections and single fibers are accessible to antibodies and other markers but imaging of such samples does not provide a three-dimensional view of the muscle. Regrettably, bundles of fibers cannot be stained or imaged easily. Two-photon microscopy techniques overcome these obstacles. Second harmonic generation (SHG) by myosin filaments and two-photon excited fluorescence (2PEF) of mitochondrial and lysosomal components provides detailed structural information on unstained tissue. Furthermore, the infrared exciting light can penetrate several layers of muscle fibers and the minimal processing is particularly valuable for fragile biopsies. Here we demonstrate the usefulness of SHG, combined with 2PEF, to reveal enlarged lysosomes and accumulations of non-contractile material in muscles from the mouse model for the lysosomal storage disorder Pompe disease (PD), and in biopsies from adult and infant PD patients. SHG and 2PEF also detect sarcomeric defects that may presage the loss of myofibrils in atrophying muscle and signify loss of elasticity. The combination of SHG and 2PEF should be useful in the analysis and diagnosis of a wide range of skeletal muscle pathologies.

Molecular and functional characterization of eight novel GAA mutations in Italian infants with Pompe disease.

We characterized 29 unrelated patients presenting with the severe form of Pompe disease (Glycogen Storage Disease Type II, acid maltase deficiency) and identified 26 pathogenic mutations divided over 28 different genotypes. Among the eight new mutations, five were exonic point mutations (c.572A>G, c.1124G>T, c.1202A>G, c.1564C>G and c.1796C>A) leading to codon changes (p.Y191C, p.R375L, p.Q401R, p.P522A and p.S599Y); two were intronic point mutations (c.-32-3C>A and c.1636+5G>C) affecting mRNA processing; one was a single base deletion (c.742delC) generating a truncated protein (p.L248PfsX20). A comprehensive evaluation, based on different methodological approaches, confirmed the detrimental effect of the eight mutations on the protein and its function. Structural alterations potentially induced by the five missense mutations were also predicted through visual inspection of the atomic model of the GAA protein, in terms of both function and spatial orientation of specific residues as well as disturbance generated by amino acid substitutions. Although the remarkable heterogeneity of the mutational spectrum in Pompe disease was already known, our data demonstrate and confirm the power of molecular and functional analysis in predicting the natural course of Pompe disease.

Molecular genetics of late onset glycogen storage disease II in Italy.

Glycogen Storage Disease Type II (GSDII) is a recessively inherited disorder due to the deficiency of acid alpha-glucosidase (GAA) that results in glycogen accumulation in the lysosomes. The molecular analysis of the GAA gene was performed on 45 Italian patients with late onset GSDII. DHPLC analysis revealed 28 polymorphisms spread all over the GAA gene. Direct sequencing identified the 96% of the mutant alleles, 12 of which are novel. Missense mutations were functionally characterized by enzyme activity and protein processing in a human GAA deficient cell line while splicing mutations were studied by RT-PCR and in silico analysis. A complex allele was also identified carrying three different alterations in cis. All the patients studied carried a severe mutation in combination with a milder one, which explains the late onset of the disease. The c.-32-13T > G was the most frequent mutation, present as compound heterozygote in 85% of the patients as described in other late onset GSDII Caucasian populations. Interestingly, 10 of the 45 patients carried the c.-32-13T > G associated to the severe c.2237G > A (p.W746X) mutation. However, despite the common genotype, patients presented with a wide variability in residual enzyme activity, age of appearance of clinical signs and rate of disease progression, suggesting that other genetic/environment factors may modulate clinical presentation.

Funtional characterization of four novel MAN2B1 mutations causing juvenile onset alpha-mannosidosis.

Alpha-mannosidosis is a recessively inherited disorder due to the deficiency of the lysosomal alpha-mannosidase. We report the molecular analysis performed in two patients with the late onset form of alpha-mannosidosis. Four new alleles were identified: three missense mutations involving highly conserved residues, c.597 C>A (p.H200N), c.1553 T>C (p.L518P) and c.2746 C>A (p.R916S) and a single nucleotide deletion, c.2660delC. In vitro expression studies in COS-1 cells demonstrated that pH200N, p.L518P and p.R916S proteins are expressed but retained no residual enzyme activity. These data are supported by structural 3D analysis which predicted that both p.L518P and p.R916S could affect the interaction of the small E-domain with the active site domain or the main body of the structure while the pH200N might alter substrate binding or other catalytic properties. Finally, the c.2660delC causes a frameshift introducing a premature stop codon (p.T887SfsX45), presuming to be a severe mutation.

Mutation profile of the GAA gene in 40 Italian patients with late onset glycogen storage disease type II.

Glycogen storage disease type II (GSDII) is a recessively inherited disorder due to the deficiency of acid alpha-glucosidase (GAA) that results in impaired glycogen degradation and its accumulation in the lysosomes. We report here the complete molecular analysis of the GAA gene performed on 40 Italian patients with late onset GSDII. Twelve novel alleles have been identified: missense mutations were functionally characterized by enzyme activity and protein processing in a human GAA-deficient cell line while splicing mutations were studied by RT-PCR and in silico analysis. A complex allele was also identified carrying three different alterations in cis. The c.-32-13T > G was the most frequent mutation, present as compound heterozygote in 85% of the patients (allele frequency 42.3%), as described in other late onset GSDII Caucasian populations. Interestingly, the c.-32-13T > G was associated with the c.2237G > A (p.W746X) in nine of the 40 patients. Genotype-phenotype correlations are discussed with particular emphasis on the subgroup carrying the c.-32-13T > G/c.2237G > A genotype.

Substrate reduction therapy in the infantile form of Tay-Sachs disease.

Substrate reduction therapy (SRT) with miglustat has been proposed for treatment of some lysosomal storage disorders. Based on the positive experience in Gaucher disease and experimental data in Tay-Sachs (TSD) and Sandhoff animal models, the authors investigated the clinical efficacy of SRT in two patients with infantile TSD. SRT could not arrest the patients' neurologic deterioration. However, a significant drug concentration in CSF as well as macrocephaly prevention were observed.

Gaucher disease and bone: laboratory and skeletal mineral density variations during a long period of enzyme replacement therapy.

The usefulness of bone turnover markers in Gaucher disease is still unclear and their utility in monitoring the effects of enzyme replacement therapy (ERT) on bone metabolism has not yet been investigated exhaustively. Skeletal involvement seems to improve slowly during ERT, but only a few studies evaluating bone mineral density (BMD) changes during a long follow-up period have been reported. The aim of this study was to assess the efficacy of ERT on bone involvement in a group of 12 type I Gaucher disease (GD I) patients by monitoring biochemical indices of bone resorption/formation and BMD measured by dual energy x-ray absorptiometry (DEXA). Serum (calcium, phosphorus, bone alkaline phosphatase isoenzyme, carboxyterminal propeptide of type I procollagen (PICP), carboxyterminal telopeptide of type I collagen (ICTP), osteocalcin, intact parathyroid hormone) and urinary (calcium, phosphorus, hydroxyproline and free deoxypyridinoline) markers of bone metabolism and lumbar BMD were measured at baseline, after 6 and 12 months, and then every year for a mean ERT follow-up period of 4.5 years (range 4.4-6 years). Twelve healthy adult subjects matched for age and sex were tested as negative controls. A significant decrease of PICP was detected in the patient group at baseline (mean value 100.52 ng/ml vs 142.45 ng/ml, p = 0.017), while ICTP was remarkably higher: mean value 3.93 ng/ml vs 2.72 ng/ml, p = 0.004 (two-sided Student's t-test). No changes in bone formation indices were observed during the follow-up period, while urinary calcium excretion increased significantly from 0.065 to 0.191 mg/mg creatinine (p = 0.0014) (repeated measures ANOVA). A significant BMD improvement was also detected after an average ERT period of 4.5 years: Z-score increased from -0.81 to -0.56 (p = 0.005) (two-sided Student's t-test). These data evidenced the ineffectiveness of the biochemical markers used in monitoring ERT efficacy in GD I skeletal involvement, whereas DEXA was demonstrated to be a reliable method with which to follow up BMD improvement.

Acid sphingomyelinase: identification of nine novel mutations among Italian Niemann Pick type B patients and characterization of in vivo functional in-frame start codon.

Niemann Pick disease (NPD) is an autosomal recessive disorder due to the deficit of lysosomal acid sphingomyelinase, which results in intracellular accumulation of sphingomyelin. In the present work we studied 18 patients with NPD type B, including five individuals who presented an intermediate phenotype characterised by different levels of neurological involvement. We identified nine novel mutations in the SMPD1 gene including six single base changes c.2T>G, c.96G>A, c.308T>C, c.674T>C, c.732G>C, c.841G>A (p.M1_W32del, p.W32X, p.L103P, p.L225P, p.W244C, p.A281T) and three frameshift mutations c.100delC, c.565dupC, c.575dupC (p.G34fsX42, p.P189fsX1 and p.P192fsX14). The novel c.2T>G (p.M1_W32del) mutation inactivates the first in-frame translation start site of the SMPD1 gene and in the homozygous status causes NPD type B indicating that in'vivo translation of wild type SMPD1 initiates from the first in-frame ATG. Moreover, the new c.96G>A (p.W32X) introduces a premature stop codon before the second in-frame ATG. As a consequence of either c.2T>G (p.M1_W32del) or c.96G>A (p.W32X), impaired translation from the first in-frame ATG results in a mild NPD-B phenotype instead of the severe phenotype expected for a complete deficiency of the enzyme, suggesting that when the first ATG is not functional, the second initiation codon (ATG33) still produces a fairly functional sphingomyelinase. Analysis of the patients'clinical and molecular data demonstrated that all five patients with the intermediate phenotype carried at least one severe mutation. No association between the onset of pulmonary symptoms and genotype was observed. Finally, the presence of c.96G>A (p.W32X), the most frequent allele among Italian NPD type B population, and c.1799G>C (p.R600P) as compound heterozygotes in association with severe mutations suggested a beneficial effect for both mutations.

Gaucher's disease with Parkinson's disease: clinical and pathological aspects.

The association between type 1 Gaucher disease and PD has been reported in the literature. The clinical picture is characterized by the predominance of bilateral akinetic-rigid signs and poor response to levodopa therapy. The authors describe four patients (two siblings) with type 1 Gaucher disease presenting with the following signs of typical PD: asymmetric onset of rigidity, resting tremor, bradykinesia, and a favorable response to Parkinson therapies.

Efficacy of multidisciplinary approach in the treatment of two cases of nonclassical infantile glycogenosis type II.

Glycogenosis type II (GSD II) is a lysosomal storage disorder due to acid alpha-glucosidase deficiency. We report the results of a clinical multidisciplinary approach in two cases of nonclassical infantile GSD II. The patients received a high-protein diet by percutaneous enteral gastrostomy (PEG), mechanical ventilatory support by tracheostomy and a physiotherapy programme. After 12 months of treatment, the patients showed significant improvement in muscular strength, nutritional state and respiratory function. Electrocardiography (ECG) and echocardiography improved in both patients. They maintained good clinical conditions for a period of 18 and 20 months, respectively; thereafter they presented with an elevated and persistent fever that was not correlated to a septic status and was not responsive to any antipyretic treatment. They deteriorated progressively and died. This study shows how a multidisciplinary approach may be useful to improve, even if temporarily, the clinical course of nonclassical infantile GSD II.

Infection of macrophage-like THP-1 cells with Mycobacterium avium results in a decrease in their ability to phosphorylate nucleolin.

This study of the phosphorylation ability of macrophage-like cells upon infection with Mycobacterium avium was undertaken to establish potential targets of the interference with host response mechanisms. Cytosolic and membrane fractions from noninfected and infected cells were incubated with [gamma-(32)P]ATP, in the presence of Mg(2+) and the absence of Ca(2+), and the patterns of phosphoproteins synthesized were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lower levels of a 110-kDa phosphoprotein were observed in association with cytosolic fractions from mycobacterium-infected cells compared to noninfected cells or cells treated with lipopolysaccharide or having ingested Escherichia coli or killed M. avium. The 110-kDa phosphoprotein was present in the soluble fraction (230,000 x g supernatant) after the kinase incubation, from where it was partially purified and identified as phosphonucleolin by amino acid sequencing. The decrease in nucleolin phosphorylation observed was not related to changes in the cytosolic or membrane levels of this protein, and was detected also in the cytosolic fraction of (32)P-labeled intact cells.

Annexins VII and XI are present in a human macrophage-like cell line. Differential translocation on FcR-mediated phagocytosis.

We have studied the divalent cation-dependent association of proteins to subcellular fractions of human macrophage-like cells before and after FcR-mediated phagocytosis. Among these proteins we have identified annexins VII and XI for the first time in these cells, along with annexins I, III, and VI. Although all of these annexins are present in the cytosolic fraction, the extent of their association to membrane and phagosome fractions from resting and stimulated cells is variable. Annexin VII translocates from cytosolic to membrane fractions after phagocytic stimulation, along with annexin I, III, and VI. Annexins VII and XI are found associated with purified phagosomes along with I, III, and VI, and this association is greater after a 24-h chase period. Our results show differences in the intracellular distribution of different annexins in macrophage-like cells on phagocytosis. Annexins VII, VI, III, and I respond to particle ingestion by translocating to phagosomes and other cell membrane structures, whereas annexin XI translocates predominantly to phagosomes, suggesting dissimilarities in their function.

In acute lymphoblastic leukemia deletion of the tumor suppressor gene P16 is associated with abnormal interferon genes.

The putative tumor-suppressor gene p16 was mapped to human chromosome 9p21, close to the interferon alpha cluster. The frequency and association of gene alterations of p16, interferon alpha and interferon beta were investigated in a total of 39 Acute Lymphoblastic Leukemia (ALL) patients. Of these, 10 patients (25.6%) presented abnormalities of at least one of the three genes studied. In 32 ALL cases studies of the three genes could be accomplished. In 23 out of 32 ALL cases the 3 genes studied were normally preserved. In the remaining 9 ALL, p16 was affected in 8 cases by homozygous deletions. In 2 patients, p16 deletion was associated with homozygous deletions for interferon alpha and interferon beta genes and in 1 case with total deletion of interferon beta 1 gene and partial deletion of interferon alpha. In the remaining 5 cases, p16 was the only gene deleted with no alteration of type I interferon genes. These data indicate that p16 gene is deleted in a higher frequency than type I interferon genes in ALL. Moreover, within the ALL group with p16 gene deletion, 37.5% are associated with interferon deletions and in general, ALL with alpha and/or beta interferon gene deletions are associated with p16 deletions. Therefore, p16 gene deletion with preserved type I interferon genes in some ALL suggests that the absence of this cdk inhibitor may disturb the normal cell cycle and favor blast transformation.

Monocyte phagolysosomal fusion in children born to human immunodeficiency virus-infected mothers.

BACKGROUND: Previously we demonstrated that monocyte phagolysosomal fusion is impaired in chronic HIV infection in adult patients. METHODS: We studied the phagolysosomal fusion of peripheral blood monocytes from 45 children vertically infected with HIV, 38 noninfected infants born to HIV-positive mothers and 14 children born to HIV-seronegative women, by a cytomorphologic method in which acridine orange is used as a fusion marker. RESULTS: The mean percentages of phagolysosomal fusion +/-SD were 42 +/- 16.1 for HIV-positive children, 55.3 +/- 15.5 for HIV-negative infants born to HIV-infected mothers and 58.2 +/- 12.7 for normal controls. Monocyte phagolysosomal fusion of HIV-infected children was significantly decreased in comparison to noninfected and normal infants (P < 0.001), while there was no difference between the two latter groups. Phagolysosomal fusion impairment in HIV-infected infants inversely correlated with age (r = -0.4527; P < 0.002) and directly correlated with CD4+ T cell counts (r = 0.393; P = 0.03). Moreover, phagolysosomal fusion strongly correlated with clinical manifestations; this function was significantly impaired in moderately and severely symptomatic HIV-infected children with respect to those who remained asymptomatic or mildly symptomatic (P < 0.05). CONCLUSIONS: Our results suggest that monocyte function in HIV-infected children progressively deteriorates, closely related to the severity of the clinical symptoms.

Recombinant human immunodeficiency virus type 1 (HIV-1) Tat protein inhibits phagolysosomal fusion in human peripheral blood monocytes.

The effect of recombinant HIV-1 Tat protein on different functions of peripheral blood monocytes, such as candidacidal activity and phagolysosomal fusion, was evaluated. HIV-1 Tat protein caused a significant impairment of phagolysosomal fusion at 100 ng/ml (p = 0.018). The inhibitory effect of Tat on phagolysosomal fusion was blocked by the addition of 1 microgram/ml monoclonal anti-Tat antibody. Candidacidal activity of peripheral monocytes was not altered by HIV-1 Tat protein at the concentration of 1 microgram/ml. These results indicate the HIV-1 Tat protein can affect the monocyte microbicidal mechanisms at the phagolysosomal fusion step with little or not effect upon the lytic activity.

Decreased phagolysosomal fusion of peripheral blood monocytes from patients with thalassemia major.

We evaluated the phagolysosomal fusion of peripheral blood monocytes from 15 patients with thalassemia major and 10 thalassemia major carriers using a cytomorphological method with acridine orange as fusion marker. The monocyte phagolysosomal fusion of thalassemic patients was decreased (49.6 +/- 8.6%, mean +/- SD) and differed significantly (p < 0.05) from those of carriers and normal controls (65.7 +/- 11.4% and 74.6 +/- 5.7%, respectively). In vitro deferoxamine partially improved monocyte phagolysosomal fusion of patients with thalassemia major, and did not affect monocyte function in carriers and healthy subjects. Furthermore, in vitro addition of ferrous sulfate decreased normal phagolysosomal fusion. We conclude that the monocyte phagolysosomal fusion dysfunction of thalassemic patients could be related to iron overload.

Impaired phagolysosomal fusion of peripheral blood monocytes from HIV-infected subjects.

We evaluated phagolysosomal fusion in peripheral blood monocytes from 20 HIV-infected individuals and 40 normal controls, using a fluorescence assay with acridine orange as marker. The percentages of phagolysosomal fusion of monocytes from HIV-infected subjects, after 30 and 60 min of yeast ingestion, (mean +/- standard deviation) 57.2 +/- 17 and 63.2 +/- 18.6, respectively, when compared to normal controls (72.4 +/- 7.8 and 77 +/- 8.1), did not differ significantly. However, there was a direct linear association between the percentages of phagolysosomal fusion and CD4+ lymphocytes (P < 0.001) or CD4/CD8 T-cell ratio (P < 0.01). These results suggest that phagolysosomal dysfunction becomes evident at late stages of HIV infection and progresses as CD4+.T-lymphocyte count and CD4/CD8 T-cell ratio decrease. On the other hand, recombinant gp120 inhibited significantly normal phagolysosomal fusion at concentrations ranging between 1 and 1000 ng/ml. Taking together the results obtained, we can conclude that gp120 could be responsible for monocyte phagolysosomal dysfunction observed in HIV infected patients.