Autoantibodies against vinculin in patients with chronic inflammatory demyelinating polyneuropathy.

To identify the target molecules of chronic inflammatory demyelinating polyneuropathy (CIDP), we used proteomic-based approach in the extracted proteins from porcine cauda equina. Two of 31 CIDP patients had markedly elevated serum autoantibodies against vinculin, a cell adhesion protein. Both of the patients with anti-vinculin antibodies had similar clinical manifestation, which are compatible with those of "typical" CIDP. Immunocytochemistry showed that vinculin was stained at the myelin sheath of the sciatic nerves by serum samples. Our results suggest that vinculin is a possible immunological target molecule in a subpopulation of typical CIDP patients.

[Alternative Splicing Detection as a Biomarker for Cancer Diagnosis: A Novel Progressive Mechanism of Acute Lymphoblastic Leukemia with Alternative Splicing as a Biomarker Candidate].

Alternative splicing is an important mechanism that links to transcription and contributes to protein diversity. Disturbed alternative splicing is frequently observed in cancers, but its precise mechanism remains largely unknown. FUSE-binding protein (FBP) -interacting repressor (FIR) is a transcriptional repressor of the c-myc gene. Previous studies indicated that a splice variant of FIR, FIRΔexon2, that lacks exon2 in the transcriptional repressor domain, was increased in colorectal cancers, hepatocellular carcinomas, and leukemia cells. Furthermore, FIRΔexon2 activated c-myc transcription by disabling wild-type FIR as a dominant-negative form of FIR. Recently, somatic mutations of the SF3B1 (SAP155) gene, a subunit of the SF3B spliceosome complex, were found in myelodysplastic leukemia. In this study, FIR heterozygous knockout (FIR(+/-)) was established as a dominant-negative model of FIR in the C57BL/6 mouse. FIR(+/-) mice showed an increased c-myc mRNA expression level, particularly in peripheral blood, although FIR(+/-) mice had no apparent pathogenic phenotype. Therefore, an increased c-myc mRNA expression level alone is not enough for leukemogenesis. Nevertheless, FIR(+/-)TP53(-/-) mice generated acute T-cell lymphoblastic leukemia (T-ALL) with increased organ and/or bone marrow invasion. In conclusion, alternative splicing of FIR, generating FIRΔexon2, contributes to not only colorectal carcinogenesis but also leukemogenesis independent of the c-Myc activation pathway. Finally, we will discuss our hypothesis that FIRΔexon2 interferes with FBW7, that FIRΔexon2 inhibits PP1 in the EGFR pathway, and that FIR haploinsufficiency is potentially associated with protein expression through transcriptional and post-transcriptional mechanisms.

Moesin is a possible target molecule for cytomegalovirus-related Guillain-Barré syndrome.

OBJECTIVE: Previous histochemical studies in the demyelinating form of Guillain-Barré syndrome (GBS), acute inflammatory demyelinating polyneuropathy (AIDP), have shown complement deposition on the surface of Schwann cells, and therefore unknown epitopes would be present on the outer surface of Schwann cells. METHODS: We used a proteomic-based approach to search for the target molecules of AIDP in the extracted proteins from schwannoma cells. Sera were obtained from 40 patients with GBS, 31 controls with inflammatory disease, and 46 normal controls. RESULTS: We found that patients with AIDP after cytomegalovirus (CMV) infection have serum autoantibodies against membrane-organizing extension spike protein (moesin), which is expressed in the Schwann cell processes at the nodes of Ranvier and is crucial for myelination. Of the 40 patients with GBS, 6 had recent CMV infection and 5 of them (83%) had high levels of serum immunoglobulin G antibodies against moesin. The anti-moesin antibodies were found in none of the control subjects with disease including 5 with CMV infection but no neuropathy, and only 2 (4%) of the 46 normal control subjects. Immunocytochemistry showed that moesin was stained at the distal tips of schwannoma cells by sera from the patients with CMV-related AIDP but not by sera from controls. CONCLUSION: Moesin is a possible immunologic target molecule of pathogenic autoantibodies in patients with CMV-related AIDP. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that levels of serum anti-moesin antibodies accurately distinguishes CMV-related AIDP from non-CMV-related AIDP (sensitivity 83%, specificity 93%).

Increased concentrations of apo A-I and apo A-II fragments in the serum of patients with hepatocellular carcinoma by magnetic beads-assisted MALDI-TOF mass spectrometry.

OBJECTIVES: Recent advances in sophisticated technologies in proteomics should provide promising ways to discover novel markers for hepatocellular carcinoma (HCC) in the early diagnosis. METHODS: Serum peptide and protein profiling was conducted by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Profiling was carried out in a training set of 16 patients with HCC and a testing set of 15 patients with cirrhosis without HCC. All the patients were hepatitis C virus positive. Candidate peaks were processed to partial purification, followed by protein identification by amino acid sequence analysis. Immunoprecipitation was conducted to confirm the protein identity. RESULTS: Partial purification and protein identification revealed that one peak that was up-regulated in HCC sera both in the training and the testing sets was a fragment of apolipoprotein A-I (apo A-I). Immunoprecipitation confirmed this result. CONCLUSIONS: MALDI-TOF MS analysis revealed that apo A-I is a potential novel serum marker of HCC. Combination of these pretreatments and the current magnet bead-assisted MALDI-TOF MS will further enhance the efficiency of biomarker discovery for HCC.