Development of a highly sensitive immuno-PCR assay for the measurement of α-galactosidase A protein levels in serum and plasma

The potential consequences of bidirectional promoter methylation on GLA and HNRNPH2 expression in Fabry disease phenotypes in a family of patients carrying a GLA deletion variant

Fabry disease (FD) is a rare inherited disease characterized by a wide range of symptoms attributed to GLA mutations resulting in defective α-galactosidase A (α-Gal A) and accumulation of glycosphingolipids. The GLA locus is paired in a divergent manner with the heterogeneous nuclear ribonucleoprotein HNRNPH2 locus mapped in the RPL36A-HNRNPH2 readthrough locus. As a follow-up to our recent finding of the co-regulation of GLA and HNRNPH2 via a bidirectional promoter (BDP) in normal kidney and skin cells, the potential accumulative influence of BDP methylation and GLA mutation on the severity of FD in patients from the same family, two males and two females carrying a GLA deletion mutation, c.1033_1034delTC (p.Ser345Argfs) was addressed in the present study. The molecular analyses of the FD patients compared with the control revealed that the expression of GLA was significantly low (P<0.05), and HNRNPH2 showed a tendency of low expression (P=0.1) when BDP methylation was elevated in FD patients, compared with low BDP methylation and high GLA expression (P<0.05), and a high trend of HNRNPH2 expression in normal individuals. The accumulative effects of the mutation and BDP methylation with the severity of the disease were observed in three patients. One male FD patient, a member of the FD family diagnosed with progressive loss of kidney function, hypertension, and eventually a stroke, and the lowest level of α-Gal A enzyme activity showed the highest BDP DNA methylation level. It is concluded that the DNA methylation of GLA-HNRNPH2 BDP may serve a role in diagnosing and treating FD.

Multiplex protein profiling method for extracellular vesicle protein detection

Extracellular vesicles (EVs) are small nanometer-sized membrane sacs secreted into biological fluids by all cells. EVs encapsulate proteins, RNAs and metabolites from its origin cell and play important roles in intercellular communication events. Over the past decade, EVs have become a new emerging source for cancer diagnostics. One of the challenges in the study of EVs and there utility as diagnostic biomarkers is the amount of EVs needed for traditional protein analysis methods. Here, we present a new immuno-PCR method that takes advantage of commercially available TotalSeq antibodies containing DNA conjugated oligos to identify immobilized protein analysts using real-time qPCR. Using this method, we demonstrate that multiple EV surface proteins can be profiled simultaneously with high sensitivity and specificity. This approach was also successfully applied to similar protocol using cell and serum samples. We further described the development of a micro-size exclusion chromatography method, where we were able to detect EV surface proteins with as little as 10 μL of human serum when combined with immuno-PCR. Overall, these results show that the immuno-PCR method results in rapid detection of multiple EV markers from small sample volumes in a single tube.

Sudden death following AV node ablation in a man with Fabry disease mimicking hypertrophic cardiomyopathy

We present a case of Fabry disease with an uncommon pattern of asymmetrical hypertrophy with septal prominence resulting in an erroneous diagnosis of hypertrophic cardilmyopathy clinically. The deceased presented for a medicolegal autopsy following his sudden death after an AV node ablation. Fabry disease continues to be an important misdiagnosis of hypertrophic cardiomyopathy in a clinical setting. Early diagnosis of Fabry disease is essential so that early treatment can be instituted.

454-Pyrosequencing Analysis of Bacterial Communities from Autotrophic Nitrogen Removal Bioreactors Utilizing Universal Primers: Effect of Annealing Temperature

Identification of anaerobic ammonium oxidizing (anammox) bacteria by molecular tools aimed at the evaluation of bacterial diversity in autotrophic nitrogen removal systems is limited by the difficulty to design universal primers for the Bacteria domain able to amplify the anammox 16S rRNA genes. A metagenomic analysis (pyrosequencing) of total bacterial diversity including anammox population in five autotrophic nitrogen removal technologies, two bench-scale models (MBR and Low Temperature CANON) and three full-scale bioreactors (anammox, CANON, and DEMON), was successfully carried out by optimization of primer selection and PCR conditions (annealing temperature). The universal primer 530F was identified as the best candidate for total bacteria and anammox bacteria diversity coverage. Salt-adjusted optimum annealing temperature of primer 530F was calculated (47°C) and hence a range of annealing temperatures of 44–49°C was tested. Pyrosequencing data showed that annealing temperature of 45°C yielded the best results in terms of species richness and diversity for all bioreactors analyzed.

Clinical and biochemical investigation of male patients exhibiting membranous cytoplasmic bodies in biopsied kidney tissues; a pitfall in diagnosis of Fabry disease

Background: The existence of membranous cytoplasmic bodies in biopsied kidney tissues is one of the important findings when considering Fabry disease as the first choice diagnosis. However, there are possible acquired lysosomal diseases associated with pharmacological toxicity, although less attention has been paid to them.

Case Presentation: We experienced 3 male patients presenting with proteinuria and specific pathological changes strongly suggesting Fabry disease. We sought detailed clinical and biochemical information to avoid a wrong diagnosis. The patients were examined clinically and pathologically, and plasma α-galactosidase A (GLA) activity and the globotriaosylsphingosine (lyso-Gb3) concentrations were measured. Electron microscopic examination revealed numerous membranous inclusion bodies in podocytes, and biochemical analysis revealed normal GLA activity and a normal lyso-Gb3 level in plasma, showing that they did not have Fabry disease. They suffered from hyperlipidemia, myeloma, or lupus nephritis. They had received pitavastatin calcium, clarithromycin, loxoprofen and/or prednisolone, and there was no medication history of cationic amphiphilic drugs.

Conclusions: In this case series, the etiology of the inclusions was not clarified. However, these cases indicate that careful attention should be paid on diagnosis of patients exhibiting inclusion bodies in kidney cells, and it is important to confirm their past and present illnesses, and medication history as well as to measure the GLA activity and lyso-Gb3 level.

Silencing of eIF3e promotes blood perfusion recovery after limb ischemia through stabilization of hypoxia-inducible factor 2α activity

OBJECTIVE

We previously observed that silencing of eukaryotic translation initiation factor 3 subunit e (eIF3e), a hypoxia-independent downregulator of hypoxia-inducible factor 2α (HIF-2α), led to neoangiogenesis by promoting HIF-2α activity under normoxic conditions. In the current study, we investigated whether temporary silencing of eIF3e in muscles affects blood flow recovery in a mouse ischemic limb model.

METHODS

eIF3e silencing was performed using small interfering RNA (siRNA), and changes in gene transcription and protein expression were analyzed in vitro using murine primary skeletal muscle myoblast and human primary skeletal muscle myoblast cell cultures. In unilateral femoral artery ligation experiments, eIF3e siRNA-expressing plasmids were injected into the muscles of BALB/c mice near the ligation sites, and tissue damage and loss of limb function were scored for 28 days while serial measurements of limb perfusions were performed with laser Doppler perfusion imaging.

RESULTS

Silencing of eIF3e in murine primary skeletal muscle myoblasts led to stabilization of HIF-2α and upregulation of angiogenic transcripts, including basic fibroblast growth factor and platelet-derived growth factor B (P < .05), and the supernatant of eIF3e-silenced human primary skeletal muscle myoblasts triggered the tube formation of human umbilical vein endothelial cells. The in vivo mouse model of hindlimb ischemia revealed that single intramuscular injections of eIF3e siRNA-expressing plasmids significantly enhanced perfusion of ischemia-damaged limbs (P < .05) at days 7 and 14 and functional recovery at days 7, 14, and 21 (P < .05).

CONCLUSIONS

eIF3e is an angiogenesis suppressor and may be a therapeutic target for promoting angiogenesis after ischemic injuries.

Plasma mutant α-galactosidase A protein and globotriaosylsphingosine level in Fabry disease

Fabry disease is an X-linked genetic disorder characterized by deficient activity of α-galactosidase A (GLA) and accumulation of glycolipids, and various GLA gene mutations lead to a wide range of clinical phenotypes from the classic form to the later-onset one. To investigate the biochemical heterogeneity and elucidate the basis of the disease using available clinical samples, we measured GLA activity, GLA protein and accumulated globotriaosylsphingosine (Lyso-Gb3), a biomarker of this disease, in plasma samples from Fabry patients. The analysis revealed that both the enzyme activity and the protein level were apparently decreased, and the enzyme activity was well correlated with the protein level in many Fabry patients. In these cases, a defect of biosynthesis or excessive degradation of mutant GLAs should be involved in the pathogenesis, and the residual protein level would determine the accumulation of Lyso-Gb3 and the severity of the disease. However, there are some exceptional cases, i.e., ones harboring p.C142Y, p.R112H and p.M296I, who exhibit a considerable amount of GLA protein. Especially, a subset of Fabry patients with p.R112H or p.M296I has been attracted interest because the patients exhibit almost normal plasma Lyso-Gb3 concentration. Structural analysis revealed that C142Y causes a structural change at the entrance of the active site. It will lead to a complete enzyme activity deficiency, resulting in a high level of plasma Lyso-Gb3 and the classic Fabry disease. On the other hand, it is thought that R112H causes a relatively large structural change on the molecular surface, and M296I a small one in a restricted region from the core to the surface, both the structural changes being far from the active site. These changes will cause not only partial degradation but also degeneration of the mutant GLA proteins, and the degenerated enzymes exhibiting small and residual activity remain and probably facilitate degradation of Lyso-Gb3 in plasma, leading to the later-onset phenotype. The results of this comprehensive analysis will be useful for elucidation of the basis of Fabry disease.