Expression profiles of adult T-cell leukemia-lymphoma and associations with clinical responses to zidovudine and interferon alpha

Adult T-cell leukemia-lymphoma (ATLL) is an HTLV-1-associated lymphoproliferative malignancy that is frequently fatal. We compared gene expression profiles (GEPs) of leukemic specimens from nine patients with ATLL at the time of diagnosis and immediately after combination therapy with zidovudine (AZT) and interferon alpha (IFNalpha). GEPs were also related to genetic aberrations determined by comparative genomic hybridization. We identified several genes anomalously over-expressed in the ATLL leukemic cells at the mRNA level, including LYN, CSPG2, and LMO2, and confirmed LMO2 expression in ATLL cells at the protein level. In vivo AZT-IFNalpha therapy evoked a marked induction of interferon-induced genes accompanied by repression of cell-cycle regulated genes, including those encoding ribosomal proteins. Remarkably, patients not responding to AZT-IFNalpha differed most from responding patients in lower expression of these same IFN-responsive genes, as well as components of the antigen processing and presentation apparatus. Demonstration of specific gene expression signatures associated with response to AZT-IFNalpha therapy may provide novel insights into the mechanisms of action in ATLL

Abnormal Speech Spectrum and Increased Pitch Variability in Young Autistic Children

Children with autism spectrum disorder (ASD) who can speak often exhibit abnormal voice quality and speech prosody, but the exact nature and underlying mechanisms of these abnormalities, as well as their diagnostic power are currently unknown. Here we quantified speech abnormalities in terms of the properties of the long-term average spectrum (LTAS) and pitch variability in speech samples of 83 children (41 with ASD, 42 controls) ages 4–6.5 years, recorded while they named a sequence of daily life pictures for 60 s. We found a significant difference in the group's average spectra, with ASD spectra being shallower and exhibiting less harmonic structure. Contrary to the common impression of monotonic speech in autism, the ASD children had a significantly larger pitch range and variability across time. A measure of this variability, optimally tuned for the sample, yielded 86% success (90% specificity, 80% sensitivity) in classifying ASD in the sample. These results indicate that speech abnormalities in ASD are reflected in its spectral content and pitch variability. This variability could imply abnormal processing of auditory feedback or elevated noise and instability in the mechanisms that control pitch. The current results are a first step toward developing speech spectrum-based bio-markers for early diagnosis of ASD

Role of an adaptor protein human germinal center-associated lymphoma (HGAL) in cell signaling and lymphomagenesis

Human germinal center (GC)-associated lymphoma (HGAL) is a multi-domain adaptor protein expressed in GC B lymphocytes, T follicular helper (Tfh) cells and lymphomas derived from these cells. HGAL expression is an independent predictor of longer survival of diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin’s lymphoma (HL) patients. HGAL regulates B cell receptor (BCR) signaling and immunological synapse formation by binding to either the downstream effectors [e.g., spleen tyrosine kinase (Syk)] or other signaling regulators [e.g., growth factor receptor-bound protein 2 (Grb2)]. HGAL regulates the cytoskeleton that reshapes B cell morphology during BCR signaling and cell motility by at least two molecular mechanisms: enhanced Ras homolog gene family member A (RhoA) signaling and inhibition of myosin-actin translocation. These effects on the cytoskeleton decrease lymphoma dissemination in animal models and contribute to decreased lymphoma dissemination in patients. The latter may contribute to the association of HGAL protein expression with longer survival of patients with DLBCL and HL tumors. The ability to regulate multiple and distinct functions simultaneously in B cells implies that the HGAL protein level is tightly regulated. It was demonstrated that HGAL can be regulated by PR/SET domain 1 (PRDM1)/B lymphocyte-induced maturation protein-1 (BLIMP1) and interleukin-4 (IL-4) at the transcription level, by microRNA-155 (miR-155) at the post-transcriptional level, and by F-box protein 10 (FBXO10) at the post-translational level. Constitutive enforced expression of HGAL at physiological levels leads to lymphoid hyperplasia and DLBCL in mice. Future studies need to focus on identifying HGAL interactome, dissecting its interaction network, and understanding HGAL spatiotemporal signaling in live cells in physiological conditions. Further, the recent demonstration of HGAL expression in Tfh cells requires the determination of its function in these cells. These studies will contribute to new insights into the biology of these cellular subsets and how immune dysregulation contributes to lymphomagenesis

Severe methylenetetrahydrofolate reductase deficiency: Clinical clues to a potentially treatable cause of adult-onset hereditary spastic paraplegia

IMPORTANCE: Hereditary spastic paraplegia is a highly heterogeneous group of neurogenetic disorders with pure and complicated clinical phenotypes. No treatment is available for these disorders. We identified 2 unrelated families, each with 2 siblings with severe methylenetetrahydrofolate reductase (MTHFR) deficiency manifesting a complicated form of adult-onset hereditary spastic paraparesis partially responsive to betaine therapy. OBSERVATIONS: Both pairs of siblings presented with a similar combination of progressive spastic paraparesis and polyneuropathy, variably associated with behavioral changes, cognitive impairment, psychosis, seizures, and leukoencephalopathy, beginning between the ages of 29 and 50 years. By the time of diagnosis a decade later, 3 patients were ambulatory and 1 was bedridden. Investigations have revealed severe hyperhomocysteinemia and hypomethioninemia, reduced fibroblast MTHFR enzymatic activity (18%-52%of control participants), and 3 novel pathogenic MTHFR mutations, 2 as compound heterozygotes in one family and 1 as a homozygous mutation in the other family. Treatment with betaine produced a rapid decline of homocysteine by 50% to 70%in all 4 patients and, over 9 to 15 years, improved the conditions of the 3 ambulatory patients. CONCLUSIONS AND RELEVANCE: Although severe MTHFR deficiency is a rare cause of complicated spastic paraparesis in adults, it should be considered in select patients because of the potential therapeutic benefit of betaine supplementation. Copyright 2014 American Medical Association. All rights reserved

Mutations in SPG11, encoding spatacsin, are a major cause of spastic paraplegia with thin corpus callosum.

Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus callosum (TCC) is a common and clinically distinct form of familial spastic paraplegia that is linked to the SPG11 locus on chromosome 15 in most affected families. We analyzed 12 ARHSP-TCC families, refined the SPG11 candidate interval and identified ten mutations in a previously unidentified gene expressed ubiquitously in the nervous system but most prominently in the cerebellum, cerebral cortex, hippocampus and pineal gland. The mutations were either nonsense or insertions and deletions leading to a frameshift, suggesting a loss-of-function mechanism. The identification of the function of the gene will provide insight into the mechanisms leading to the degeneration of the corticospinal tract and other brain structures in this frequent form of ARHSP

A 61-Year-Old Man with Dyspepsia and Weight Loss

In this case-based Learning Forum, Burton takes clinicians through the key steps in diagnosing and managing this patient

Apolipoprotein E genotype and neurological disease onset in Niemann–Pick disease, type C1

Niemann–Pick disease, type C1 (NPC1) is a lipid storage disorder that results in progressive neurological impairment. The NPC1 phenotype is extremely variable and at the individual level is likely influenced by other genetic traits. In addition to residual function of NPC1 protein, we hypothesize that modifier genes, as frequently observed with other autosomal recessive diseases, influence the NPC phenotype. The NPC1 phenotype includes progressive dementia, and the NPC pathology has some overlap with the pathology of Alzheimer disease (AD). Thus, we examined apolipoprotein E (ApoE) and microtubule‐associated protein tau (MAPT) polymorphisms in a cohort of 15 NPC1 patients with well characterized longitudinal disease progression. Although we did not find any correlations between disease severity and tau polymorphisms, we found significant associations between ApoE polymorphisms and phenotypic severity. Specifically, ApoE4 and ApoE2 alleles were associated, respectively, with increased and decreased disease severity in this cohort of NPC1 patients. These data support the hypothesis that ApoE may play a role in modulating NPC1 neuropathology. © 2012 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94247/1/35395_ftp.pd

Accumulation of Self-Reactive Naive and Memory B Cell Reveals Sequential Defects in B Cell Tolerance Checkpoints in Sjogren's Syndrome

This work was funded by grants number 18237 and 20089 from Arthritis Research UK (http://www.arthritisresearchuk.org) to MB and the William Harvey Research Foundation. EC was recipient of short-term travel fellowships from EMBO (ASTF 318-2010) and EFIS-IL

The ansamycin antibiotic, rifamycin SV, inhibits BCL6 transcriptional repression and forms a complex with the BCL6-BTB/POZ domain

BCL6 is a transcriptional repressor that is over-expressed due to chromosomal translocations, or other abnormalities, in ~40% of diffuse large B-cell lymphoma. BCL6 interacts with co-repressor, SMRT, and this is essential for its role in lymphomas. Peptide or small molecule inhibitors, which prevent the association of SMRT with BCL6, inhibit transcriptional repression and cause apoptosis of lymphoma cells in vitro and in vivo. In order to discover compounds, which have the potential to be developed into BCL6 inhibitors, we screened a natural product library. The ansamycin antibiotic, rifamycin SV, inhibited BCL6 transcriptional repression and NMR spectroscopy confirmed a direct interaction between rifamycin SV and BCL6. To further determine the characteristics of compounds binding to BCL6-POZ we analyzed four other members of this family and showed that rifabutin, bound most strongly. An X-ray crystal structure of the rifabutin-BCL6 complex revealed that rifabutin occupies a partly non-polar pocket making interactions with tyrosine58, asparagine21 and arginine24 of the BCL6-POZ domain. Importantly these residues are also important for the interaction of BLC6 with SMRT. This work demonstrates a unique approach to developing a structure activity relationship for a compound that will form the basis of a therapeutically useful BCL6 inhibitor