Skeletal muscle gene expression profiling in mitochondrial disorders

Extremely variable clinic and genetic features characterize mitochondrial encephalomyopathy (MEM). Pathogenic mitochondrial DNA (mtDNA) defects can be divided into large-scale rearrangements and single point mutations. Clinical manifestations become evident when a threshold percentage of the total mtDNA is mutated. In some MEM, the "mutant load" in an affected tissue is directly related to the severity of the phenotype. However, the clinical phenotype is not simply a direct consequence of the relative abundance of mutated mtDNA. Other factors, such as nuclear background, can contribute to the disease process, resulting in a wide range of phenotypes caused by the same mutation. Using Affymetrix oligonucleotide cDNA microarrays (HG-U133A), we studied the gene expression profile of muscle tissue biopsies obtained from 12 MEM patients [4 common 4977 bp deleted mtDNA and 8 A3243G: 4 progressive external ophthalmoplegia (PEO) and 4 mitochondrial myopathy, encephalopathy, lactic cidosis, and stroke-like episodes syndrome (MELAS) phenotypes] compared with age-matched healthy individuals. We found several differentially expressed genes: 35 were markedly up-regulated in the mtDNA macro-deletion group (vs. the control group) and 4 decreased; 56 genes were dysregulated in A3243G-related disorders (53 down-regulated in PEO and 3 up-regulated in MELAS). Finally, 12 genes were similarly regulated in the majority of the MEM patients under study. Amongst these, we identified an increased expression of genes related to the metabolism of the amino groups, as well as of several genes involved in genetic information processing. Moreover, few genes were similarly decreased in MEM patients vs. the control group. Real-time PCR demonstrated excellent reproducibility of the microarray-based findings. The observed expression changes are likely to represent a molecular signature for mitochondrial disorders. Furthermore, the differential expression profile of MELAS(A3243G) vs. PEO(A3243G) may support a role of nuclear background in contributing to these different clinical phenotypes. MEM microarray data are available from GEO database (http://www.ncbi.nlm.nih.gov/geo/) with the accession number: GSE1462.

Human skin-derived stem cells migrate throughout forebrain and differentiate into astrocytes after injection into adult mouse brain

Recent evidence indicates that neural stem cell properties can be found among a mammalian skin-derived multipotent population. A major barrier in the further characterization of the human skin-derived neural progenitors is the inability to isolate this population based on expression of cell surface markers. Our work has been devoted to purified human skin-derived stem cells that are capable of neural differentiation, based on the presence or absence of the AC133 cell surface marker. The enriched skin-derived AC133(+) cells express the CD34 and Thy-1 antigens. These cells cultured in a growth medium containing epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) proliferate, forming spheres, and differentiate in vitro into neurons, astrocytes, and rarely into oligodendrocytes. Single cells from sphere cultures initiated from human purified AC133(+) cells were replated as single cells and were able to generate new spheres, demonstrating the self-renewing ability of these stem cell populations. Brain engraftment of cells obtained from human purified AC133(+)-derived spheres generated different neural phenotypes: immature neurons and a most abundant population of well differentiated astrocytes. The AC133-derived astrocytes assumed perivascular locations in the frontal cortex. No donor-derived oligodendrocytes were found in the transplanted mouse brains. Several donor small, rounded cells that expressed endothelial markers were found close to the host vessel and near the subventricular zone. Thus, mammalian skin AC133-derived cells behave as a multipotent population with the capacity to differentiate into neural lineages in vitro and, prevalently, endothelium and astrocytes in vivo, demonstrating the great plasticity of these cells and suggesting potential clinical application.

Developmental and tissue-specific regulation of a novel dysferlin isoform

Dysferlin plays an essential role in the muscle repair machinery, and its deficiency is associated with limb-girdle muscular dystrophy type 2B and with two different distal myopathies (Miyoshi myopathy and distal anterior compartment myopathy). Our aims were to characterize the pattern of dysferlin expression during myogenic cell differentiation and to assess possible differentially spliced isoforms of the DYSF gene. Human primary myogenic cells express a splice variant of dysferlin mRNA lacking exon 17 (Delta17), together with full-length dysferlin mRNA. Real-time polymerase chain reaction analysis of human myoblasts, myotubes, and normal skeletal muscle showed that Delta17 expression inversely correlates with muscle differentiation. Indeed, Delta17 is progressively replaced by the wild type as myoblast fusion proceeds, and it disappears in adult skeletal muscle. Conversely, Delta17 is the predominant dysferlin variant in mature peripheral nerve. Our findings suggest that the two proteins play different roles in myogenic cell differentiation and that dysferlin function in peripheral nerve might be accomplished by this novel isoform.

Neuronal differentiation of murine bone marrow Thy-1- and Sca-1-positive cells

Recent evidence suggests that cells from bone marrow can acquire neuroectodermal phenotypes in cell culture or after transplantation in animal models and in the human brain. However, isolation of the bone marrow cell subpopulation with neuronal differentiation potential remains a challenge. To isolate and expand neural progenitors from whole murine bone marrow, bone marrow was obtained from hind limb bone of C57BL6 mice and plated in culture with neuronal medium with basic fibroblast growth factor and epidermal growth factor. After 5-7 days in culture, cellular spheres similar to brain neurospheres appeared either floating or attached to culture dishes. These spheres were collected, dissociated, and expanded. The bone marrow-derived spheres were positive for nestin as assessed by immunocytochemistry and by reverse transcriptase polymerase chain reaction. Thy-1- and Sca-1-positive bone marrow cells selected by magnetic cell sorting resulted in a higher yield of nestin-positive spheres. After exposure to neuronal differentiative medium retinoic acid with and without Sonic hedgehog, cells positive for neuronal markers tubulin III (TuJ-1) and neurofilament (NF) were detected. The mRNA profile of these cells included the expression of TuJ-1, neuronal-specific enolase (NSE), and NF-light chain. To evaluate the in vivo behavior of these cells, spheres derived from bone marrow-derived cells of transgenic green fluorescent protein (GFP) mice were transplanted into newborn mouse brain. Two months later, the mouse neural cortex contained a minor proportion of GFP(+) cells co-expressing neuronal markers (TuJ-1, NF, MAP-2, NeuN). Although cell fusion phenomena with the host cells could not be ruled out, bone marrow-derived neurosphere transplantation could be a strategy for cellular mediated gene therapy.

A new mitochondrial DNA mutation in ND3 gene causing severe Leigh syndrome with early lethality

We describe a new mitochondrial DNA mutation in a male infant who presented clinical and magnetic resonance imaging features of Leigh syndrome and died at the age of 9 mo. The patient's development was reportedly normal in the first months of life. At the age of 5 mo, he presented severe generalized hypotonia, nystagmus, and absent eye contact. Laboratory examination showed increased lactate and pyruvate in both serum and cerebrospinal fluid. Brain magnetic resonance imaging revealed multiple necrotic lesions in the basal ganglia, brain stem, and thalamus. Muscle histopathology was unremarkable, whereas respiratory chain enzyme analysis revealed a severe complex I deficiency. The patient died after an acidotic coma at age 9 mo. Sequence analysis of the entire mtDNA disclosed a new T10158C mutation with variable tissue heteroplasm (muscle: 83%; blood: 48%). The mutation was undetectable in the blood of his unaffected mother. The transition changes a serine residue into a proline, in a highly conserved region of the NADH dehydrogenase subunit 3 (ND3). This is the first description of a mitochondrial ND3 gene in Leigh syndrome with early lethality.

An intragenic deletion/inversion event in the DMD gene determines a novel exon creation and results in a BMD phenotype

Duchenne and Becker Muscular Dystrophy (DMD and BMD) are caused, in the majority of cases, by deletions in the dystrophin gene ( DMD). Here we describe the unprecedented case of a BMD patient carrying a large out-of-frame intragenic deletion, together with an inversion in the DMD gene, resulting in the inclusion of a novel exon in the transcript. Multiplex PCR amplification revealed the presence of a 48-52 exon deletion, but transcript analysis identified two unexpected products, neither of them including exon 53. The shorter mRNA derived from the juxtaposition of exons 47-54 (in-frame), while the longer one resulted from the inclusion of a novel 73-bp exon between exons 47 and 54. Sequence analysis revealed that the inserted sequence derived from an inverted portion of intron 53; its inclusion is predicted to determine protein truncation. The presence of a genomic inversion involving exon 53 and flanking regions was confirmed, and inversion/deletion breakpoints were sequenced. The inverted 73-bp sequence displays splicing signals at both ends and thus it is probably recognized as a novel exon when the partially inverted hnRNA is processed. These findings highlight the importance of mRNA analysis on patients that, based on routine DNA screenings, do not follow the reading-frame rule. This is the first reported patient carrying both an intragenic deletion and inversion in the DMD locus. This case might provide further insight into both the mechanisms that determine genomic rearrangements in the DMD locus and the molecular signals that drive exon inclusion.

Alternative sources of neurons and glia from somatic stem cells

Stem cell populations have been shown to be extremely versatile: they can generate differentiated cells specific to the tissue in which they reside and descendents that are of different germ layer origin. This raises the possibility of obtaining neuronal cells from new biological source of the same adult human subjects. In this study, we found that epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) cooperated to induce the proliferation, self-renewal, and expansion of neural stem cell-like population isolated from several newborn and adult mouse tissues: muscle and hematopoietic tissues. This population, in both primary culture and secondary expanded clones, formed spheres of undifferentiated cells that were induced to differentiate into neurons, astrocytes, and oligodendrocytes. Brain engraftment of the somatic-derived neural stem cells generated neuronal phenotypes, demonstrating the great plasticity of these cells with potential clinical application.

Skeletal muscle differentiation potential of human adult bone marrow cells

Murine bone marrow (BM) cells have been shown to undergo myogenic differentiation and participate in muscle repair in different muscle regeneration models. In the present paper, we report on a subset of cells (CD45+/desmin+) with myogenic potential being present at very low frequencies in human adult BM. By a simple culture method, we were able to obtain in vitro multinucleated myotubes in up to 20% of the cultures. Myotubes were generated using both BM flushed from rib fragments obtained during thoracotomy and BM derived from iliac crest aspirates. Cells of the different adherent and non-adherent fractions expressed numerous muscle specific markers by immunocytochemistry, real-time RT-PCR, flow cytometry, and Western blot analyses. Moreover, direct injection of whole BM into the right tibialis anterior muscle of immunodeficient mice (NOD/RAG) that had previously been treated with cardiotoxin to induce muscle degeneration, showed a variable but significant level of human cell engraftment (from 0.06 to 0.26% Dys+/FISH+ fibers). These data suggest that cells with skeletal muscle differentiation potential are present in adult human BM can differentiate in vitro and give rise to myogenic cells in vivo in immunodeficient mice after muscle damage. Further improvements might allow new approaches to cell-mediated therapies for muscular diseases.

A CAV3 microdeletion differentially affects skeletal muscle and myocardium

BACKGROUND

Caveolin-3 is the muscle-specific protein product of the caveolin gene family and an integral membrane component of caveolae. Mutations in the gene encoding caveolin-3 (CAV3) underlie four distinct disorders of skeletal muscle: the autosomal dominant form of limb-girdle muscular dystrophy type 1C (LGMD-1C), rippling muscle disease (RMD), sporadic and familial forms of hyperCKemia, and distal myopathy.

OBJECTIVE

To characterize a multigenerational Italian family affected by an autosomal dominant myopathic disorder and to assess the expression of caveolin-3, dystrophin, dystrophin-associated glycoproteins, and neuronal nitric oxide synthase in the myocardium of an affected patient.

METHODS

Clinical analysis involved 15 family members. Skeletal muscle expression of sarcolemmal proteins was evaluated by immunohistochemistry and western blot analysis in three affected individuals. Caveolar structures were analyzed through electron microscopy in muscle biopsies and in one heart biopsy.

RESULTS

CAV3 genetic analysis showed a heterozygous 3-bp microdeletion (328-330del) in affected individuals, resulting in the loss of a phenylalanine (Phe97del) in the transmembrane domain. In the skeletal muscle, the mutation was associated with severe caveolin-3 deficiency and caveolar disorganization, whereas the expression of the other analyzed muscle proteins was unaltered. Remarkably, caveolin-3 was expressed in myocardium at a level corresponding to about 60% of that of control individuals and was correctly localized at the myocardial cell membranes, with preservation of cardiac myofiber caveolar structures. Clinical analysis revealed the concomitant presence in this family of the following phenotypes: RMD, LGMD, and hyperCKemia.

CONCLUSIONS

Intrafamilial phenotypic heterogeneity is associated with caveolin-3 Phe97 microdeletion. The molecular network interacting with caveolin-3 in skeletal muscle and heart may differ.

Molecular analysis of LGMD-2B and MM patients: identification of novel DYSF mutations and possible founder effect in the Italian population

Dysferlin, the protein product of the dysferlin gene (DYSF), has been shown to have a role in calcium-induced membrane fusion and repair. Dysferlin is absent or drastically reduced in patients with the following autosomal recessive disorders: limb-girdle muscular dystrophy type 2B (LGMD-2B), Miyoshi myopathy (MM) and distal anterior compartment myopathy. To date, less than 45 mutations have been described in DYSF and a wide inter- and intra-familial variation in clinical phenotype has been associated with the same mutation. This observation underlines the relevance of any new report describing genotype/phenotype correlations in dysferlinopathic patient and families. Here we present the results of clinical, biochemical and genetic analysis performed on one MM and three LGMD Italian families. By screening the entire coding region of DYSF, we identified three novel mutations (two missense substitutions and one frame shift microdeletion). The possible existence of a founder effect for the Arg959Trp mutation in the Italian population is discussed.

Clinical, morphological and immunological evaluation of six patients with dysferlin deficiency

Limb girdle muscular dystrophy (LGMD) type 2B and distal Miyoshi myopathy (MM) are caused by mutations in a recently discovered mammalian gene coding for a skeletal muscle protein called dysferlin. The protein is normally expressed at the skeletal muscle level and absent or reduced in affected patients. We selected a clinically heterogeneous population of Italian myopathic patients with clinical evidence of myopathy and/or hyperCKemia, EMG myopathic pattern, and no alterations of the dystrophin-sarcoglycan complex. Calpain, merosin, emerin and caveolin were also tested and found normal in all patients. Dysferlin immunohistochemical and Western blot analyses allowed us to identify six patients with dysferlin deficiency: one with distal myopathy, four with limb girdle myopathy and one with hyperCKemia. No apoptosis was found in any of the six muscle specimens, although expression of the pro-apoptotic Fas antigen was mildly increased in two cases. Inflammatory reactions were present in two of the six cases, but we found no evidence of immune-mediated processes.

Two dystrophin proteins and transcripts in a mild dystrophinopathic patient

Two muscle dystrophin transcripts and proteins were detected in a 17-year-old boy with a persistently elevated serum creatine kinase level. A decreased amount of full-length dystrophin and a 360 kDa polypeptide lacking the COOH-terminus were detectable in the patient's muscle biopsy; accordingly, transcript analysis revealed the expression of a wild type messenger RNA together with a shorter frameshifted one. No genomic DNA mutation was found and the presence of a somatic mosaicism was excluded. This dystrophinopathy may be caused by a novel dystrophin gene transcriptional defect, namely aberrant intraexonic splicing.

A subpopulation of murine bone marrow cells fully differentiates along the myogenic pathway and participates in muscle repair in the mdx dystrophic mouse

Bone marrow (BM) transplantation in mice suggests the existence of pluripotent cells able to differentiate into skeletal muscle tissue, although sustained myofiber reconstitution has not yet been achieved. We investigated the myogenic potential of mouse BM cells and evaluated whether a BM fraction enriched for cells expressing skeletal muscle markers would ameliorate muscle repair, when compared to whole BM, into the dystrophic mdx mouse. We demonstrate that cells expressing striated-muscle-specific proteins are already present in the BM independently from experimentally forced myogenic conversion. We observed the presence of both markers of early myogenic program such as Pax3, Myf5, MyoD, desmin, and late myogenesis such as myosin heavy chain and alpha-sarcomeric actin. These myogenic cells are more represented in the early nonadherent BM fraction, which generates clones able to fully differentiate into myotubes. Transplantation in mdx mice by intravenous injection of whole BM and a tenfold BM myogenic enriched fraction resulted in BM reconstitution and limited dystrophin restoration. Taken together, these data show that a fraction of BM cells have a definite potential for differentiation along the skeletal muscle pathway and can be recruited by muscle repair mechanisms. They also indicate that factors limiting the degree of muscle recruitment and the host stem cell competition should be assessed in order to evaluate the usefulness of BM-derived myogenic cells into the context of cell-mediated gene therapy of inherited muscle diseases.

Retrospective study of a large population of patients affected with mitochondrial disorders: clinical, morphological and molecular genetic evaluation

Mitochondrial disorders are human genetic diseases with extremely variable clinical and genetic features. To better define them, we made a genotype-phenotype correlation in a series of 207 affected patients, and we examined most of them with six laboratory examinations (serum CK and basal lactate levels, EMG, cardiac and EEG studies, neuroradiology). We found that, depending on the genetic abnormality, hyperckemia occurs most often with either chronic progressive external ophthalmoplegia (CPEO) and ptosis or with limb weakness. Myopathic EMGs are more common than limb weakness, except in patients with A8344G mutations. Peripheral neuropathy, when present, is always axonal. About 80% of patients with A3243G and A8344G mutations have high basal lactate levels, whereas pure CPEO is never associated with increased lactate levels. Cardiac abnormalities mostly consist of conduction defects. Abnormalities on CT or MRI of the brain are relatively common in A3243G mutations independently of the clinical phenotype. Patients with multiple mtDNA deletions are somehow "protected" against the development of abnormalities with any of the tests. We conclude that, despite the phenotypic heterogeneity of mitochondrial disorders, correlation of clinical features and laboratory findings may give the clinician important clues to the genetic defect, allowing earlier diagnosis and counselling.

Beta-enolase deficiency, a new metabolic myopathy of distal glycolysis

A severe muscle enolase deficiency, with 5% of residual activity, was detected in a 47-year-old man affected with exercise intolerance and myalgias. No rise of serum lactate was observed with the ischemic forearm exercise. Ultrastructural analysis showed focal sarcoplasmic accumulation of glycogen beta particles. The enzyme enolase catalyzes the interconversion of 2-phosphoglycerate and phosphoenolpyruvate. In adult human muscle, over 90% of enolase activity is accounted for by the beta-enolase subunit, the protein product of the ENO3 gene. The beta-enolase protein was dramatically reduced in the muscle of our patient, by both immunohistochemistry and immunoblotting, while alpha-enolase was normally represented. The ENO3 gene of our patient carries two heterozygous missense mutations affecting highly conserved amino acid residues; a G467A transition changing a glycine residue at position 156 to aspartate, in close proximity to the catalytic site, and a G1121A transition changing a glycine to glutamate at position 374. These mutations were probably inherited as autosomal recessive traits since the mother was heterozygous for the G467A and a sister was heterozygous for the G1121A transition. Our data suggest that ENO3 mutations result in decreased stability of mutant beta-enolase. Muscle beta-enolase deficiency should be considered in the differential diagnosis of metabolic myopathies due to inherited defects of distal glycolysis.

Primary beta-sarcoglycanopathy manifesting as recurrent exercise-induced myoglobinuria

We report an unusual presentation of a primary beta-sarcoglycanopathy (LGMD type 2E). A 12- year-old boy came to our attention after six episodes of exercise-induced myoglobinuria. Electromyogram showed mild myopathic features of the proximal lower limb muscles. Electrocardiogram was normal. Neurological examination revealed normal muscle strength and reduced deep tendon reflexes. A muscle biopsy showed rare regenerating fibers; the immunohistochemistry was normal for dystrophin, while all the sarcoglycans were diffusely decreased. Western blot analysis showed a relevant decrease of all sarcoglycan proteins and a mild dystrophin reduction. beta-Sarcoglycan gene analysis demonstrated a compound heterozygous status for these mutations: a novel A-T base pair substitution at nucleotide 85 in exon 2, changing the codon Arg to a stop codon; a C-T base pair substitution at nucleotide 272 in exon 3 changing a Arg to a Cys residue. We consider that exercise-induced myoglobinuria may be the presenting sign of primary beta-sarcoglycanopathy.

Chronic alcohol exposure of rats exacerbates apoptosis in hepatocytes and sinusoidal endothelial cells

Background/aims: The liver apoptotic response to chronic alcohol consumption remains poorly characterized. The purpose of this study was to determine in rats the effects of chronic alcohol consumption on the relative magnitude of apoptosis in two major targets of alcohol-induced liver injury: the hepatocyte (Hep) and sinusoidal endothelial cell (SEC). Methods: Rats were fed a liquid diet containing either alcohol or isocaloric amounts of maltose-dextrin for 14 weeks. Hep and SEC were isolated by liver perfusion with collagenase followed by centrifugal elutriation. The state of the liver was assessed on the basis of light microscopic appearance, plasma liver enzymes (alanine and aspartate:2-oxoglutarate amino transferases), and the content of malondialdehyde in Hep. Apoptosis was assessed on the basis of DNA fragmentation in the whole organ (TUNEL), and caspase-3 and -8 activity in isolated cells. A mechanistic approach was also undertaken by measuring mRNA expression and the amount of protein for Fas/CD95, Fas ligand, caspase-3, Bax, Bcl-X(L), and Bcl-2 in the isolated Hep and SEC. Results: The livers of alcohol-fed rats displayed prominent steatosis. Oxidative stress was also present as reflected by an increase in the malondialdehyde content of Hep. Alcohol consumption increased apoptosis in the whole liver assessed on the basis of TUNEL procedure and in Hep and SEC as reflected by significant increase in caspase-3 activity. Of the multiple pro- and anti-apoptotic factors determined in this study, significant changes as assessed by both mRNA expression and the amount of proteins, were observed only in the SEC compartment. Conclusions: The data presented in this study indicate that: (1) chronic alcohol consumption in rats leads to a moderate augmentation of apoptosis in the whole liver and in two liver cell types which are targets for injury in alcoholic liver disease: Hep and SEC; (2) the mechanisms recruited/activated by these two types of liver cells to initiate and execute apoptosis in response to alcohol vary with the cell type.

Apoptosis and dysregulated ceramide metabolism in a murine model of alcohol-enhanced lipopolysaccharide hepatotoxicity

BACKGROUND

The role of apoptosis in EtOH-induced liver injury has not been investigated much. Therefore, the question whether apoptosis is a contributory factor to alcoholic liver disease remains to be answered. The purpose of this study was to characterize the liver apoptotic response in a murine model of alcohol-enhanced lipopolysaccharide (LPS) hepatotoxicity.

METHODS

Mice were fed an alcohol-containing liquid diet for 49 days followed by an acute LPS challenge. The liver state was judged on the basis of histological appearance, plasma liver enzyme activity (alanine:2-oxoglutarate and aspartate:2-oxoglutarate aminotransferases, as markers of hepatocytolysis), and plasma hyaluronan levels (as a marker of the sinusoidal endothelial cell scavenging function). The liver apoptotic response was assessed by DNA fragmentation (TUNEL procedure), and caspases-3 and -8 activity. To determine if ceramide played a role in the liver apoptotic response, the activity of acidic sphingomyelinase and tissue content of ceramide were also quantified.

RESULTS

Alcohol exposure induced fat accumulation and sensitized the liver to LPS injurious effects. Plasma liver enzyme activity was elevated by alcohol and this effect was potentiated by LPS. Liver apoptosis was augmented by both alcohol and LPS treatment as reflected by high frequency of positive TUNEL staining nuclei and by an increased activity of caspase-3 and -8. Acidic sphingomyelinase activity was also increased and it was associated with an elevated tissue content of ceramide. In addition, LPS also increased plasma TNF-alpha levels. These changes were accompanied by elevated plasma hyaluronan, reflecting an impaired sinusoidal endothelial cell scavenging function.

CONCLUSIONS

These results provide a more complete description of the liver apoptotic response to both alcohol and LPS and may constitute the basis for further mechanistic studies on a possible role apoptosis may play in alcoholic liver injury.

Alcohol feeding and lipopolysaccharide injection modulate apoptotic effectors in the rat pancreas in vivo

The purpose of this study was to determine if alcohol consumption and endotoxin injection change the rate of apoptosis in the pancreas. Rats were fed a Lieber-DeCarli diet for 14 weeks. At 14 weeks, the animals were injected with lipopolysaccharide (LPS) or saline and killed. The pancreata were resected and snap frozen. Apoptosis was detected by TUNEL assay. Caspase-3 activity, Bcl-2 (protein), and Fas ligand (mRNA) were assayed in pancreas extracts and alpha-amylase in plasma. Alcohol feeding significantly decreased alpha-amylase and caspase-3 activity, and significantly increased Bcl-2. LPS injection increased caspase-3 activity and decreased Bcl-2. Fas ligand mRNA was increased only in alcohol-fed, LPS-injected rats. TUNEL labeling was significantly increased only in alcohol-fed, LPS-injected rats. These data show that (a) long-term alcohol feeding suppresses apoptosis in the pancreas; (b) LPS increases the rate of apoptosis in the pancreas; (c) caspase-3 activity and Bcl-2 expression change in opposite directions; (d) TUNEL positivity and Fas ligand expression are increased, and Bcl-2 is decreased in ethanol-fed + LPS-injected rats. These results suggest that prolonged alcohol consumption may sensitize acinar cells to endotoxin-induced injury and raise the possibility that a similar mechanism may cause pancreatitis in human alcoholics.

A sporadic, atypical case of desminopathy: morphological and immunological characterization

Recently, abnormal expression of cyclin-dependent kinases was proposed as a possible cause of desminopathy. We describe an atypical case clinically characterized by severe respiratory distress. Muscle biopsy showed subsarcolemmal and intracytoplasmic accumulation areas, which intensively stained with anti-desmin antibodies and contained electrondense filamentous material at ultrastructural level. WB analysis showed 30% increased desmin signal compared to controls. Positive immunostain for CDC2 kinase, CDK2 and emerin and nuclear matrix-associated protein were, found in desmin-positive fibres.

Modulation of caspase-3 activity and Fas ligand mRNA expression in rat liver cells in vivo by alcohol and lipopolysaccharide

The purpose of this study was to determine if exacerbation of apoptosis precedes liver injury during chronic exposure of rats to alcohol. After 7 weeks of feeding an alcohol- or dextrin-containing liquid diet, the animals were treated with gram-negative bacterial lipopolysaccharide (1 mg x kg(-1) body weight, intravenously) or sterile saline and sacrificed 3 hr after the treatment. Alanine:2-oxoglutarate aminotransferase (ALT) and lactate:NAD oxidoreductase [lactate dehydrogenase (LDH)] were measured in plasma. The caudate lobe of the liver was resected for histology, while the rest of the organ was perfused with collagenase to isolate hepatocytes, Kupffer cells (KCs), and sinusoidal endothelial cells (SECs) by centrifugal elutriation. Hepatocyte mitochondria were isolated by differential centrifugation of the cell homogenate. Reduced and oxidized glutathione (GSH and GSSG) in isolated hepatocytes and hepatocyte mitochondria, and malondialdehyde in hepatocytes were assayed. Caspase-3 activity and Fas ligand mRNA expression were determined in hepatocytes, KCs, and SECs. Plasma ALT and LDH activity, liver histology, GSH, GSSG and their ratio, and malondialdehyde content were not affected by alcohol treatment Caspase-3 activity was significantly increased in alcohol-treated rats in all three cell types, with the lowest response observed in hepatocytes and the highest in KCs. Fas ligand mRNA expression, which had the highest level in SECs, followed by KCs and hepatocytes, was not affected by alcohol administration. Lipopolysaccharide had the following effects: an increase in ALT in both pair- and alcohol-fed rats, and LDH only in alcohol-fed rats, a decrease in GSH + GSSG levels in both mitochondria and hepatocytes, an elevation of malondialdehyde content in hepatocytes, a raise in caspase-3 activity in all groups and cell types, and an augmentation of Fas ligand expression in hepatocytes and KCs, but not in SECs. These data suggest that, during chronic alcohol consumption, an exacerbated apoptosis precedes alcohol-induced liver injury.

Sarcoglycan deficiency in a large Italian population of myopathic patients

Autosomal recessive limb-girdle muscular dystrophies are a heterogeneous group of genetic diseases with a wide spectrum of clinical severity and age of onset; mutations in the gene encoding the dystrophin-associated sarcoglycan proteins (alpha, beta, gamma and delta) have recently been shown to cause some cases of these myopathies (primary sarcoglycanopathies, types 2D, 2E, 2C and 2F, respectively). In this study we have examined a large population of Italian myopathic patients to determine the frequency of (alpha-, beta- and gamma-sarcoglycan deficiency and to correlate molecular defects with clinical phenotypes; to exclude the presence of primary dystrophinopathies both genetic and immunological analysis of dystrophin was performed. We report 12 patients (10 male and 2 female) with deficiency of either one or more sarcoglycan proteins. They were aged 8-56 years with onset between 4 and 30 years of age; they all presented with either mild, moderate or severe limb-girdle involvement associated with elevated blood creatine kinase levels and myopathic pattern at EMG; one was also affected with a mild dilation cardiomyopathy. All patients, except one, showed pathological muscle histological changes. Absence of all three proteins always correlates with severe forms, whereas mild protein deficiencies or isolated partial alpha-sarcoglycan deficiency correlate with either severe, moderate or mild forms.