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Raz Somech

Publications and source records attributed to Raz Somech.

13 recordsLinked to original sources
PubMed2025

RELA Haploinsufficiency Manifesting as an Atypical Phenotype of Crohn's Disease.

BACKGROUND: Mutations in RELA, a key component of NF-κB signaling, are associated with dysregulated immune responses and inflammatory disorders. While immunodeficiency phenotypes associated with RELA haploinsufficiency have been reported, gastrointestinal manifestations remain poorly described. This study aimed to characterize the clinical, genomic, and immunological features of a patient presenting with an atypical Crohn's-like phenotype driven by RELA haploinsufficiency. METHODS: Whole-exome sequencing was performed, and results were confirmed by Sanger sequencing. Protein modeling, Western blotting, immunofluorescence, and nuclear extract-based NF-κB activation assays were conducted to assess the functional impact of the identified variant. Immune profiling was performed using mass cytometry time of flight (CyTOF) and single-cell RNA sequencing (scRNA-seq) and compared to controls. RESULTS: We studied a 17-year-old male diagnosed with pan-enteric Crohn's disease (CD), perianal fistulas, chronic mucocutaneous candidiasis, and chronic lymphopenia. Sequencing identified a heterozygous missense variant in RELA (c.587T>C, p.V196A) that potentially impairs RelA (p65) protein stability, confirmed by reduced activity and diminished protein expression. CyTOF analysis revealed decreased circulating T regulatory cells (Tregs), absence of mucosal Tregs, high apoptotic rates, and elevated IFN-γ induced levels, while scRNA-seq demonstrated a robust type I/II interferon signature in multiple immune subsets. Dysregulated mucosal-associated invariant T (MAIT) and cytotoxic CD4+ T cells exhibited upregulation of IL23R and ADAM12, further linking RELA dysfunction to enhanced pro-inflammatory T cell response and tissue inflammation. CONCLUSION: This study links RELA haploinsufficiency with CD-like features, Th1/Th17 polarization, and interferon-driven inflammation, emphasizing the importance of genetic evaluation in patients with atypical or refractory IBD.

Humans↗
PubMed2007

Pseudotumor cerebri after allogeneic bone marrow transplant associated with cyclosporine a use for graft-versus-host disease prophylaxis.

Pseudotumor cerebri (PTC) is a syndrome of increased intracranial pressure for which several risk factors have been described. We report 2 patients who developed PTC after cyclosporine A (CsA) therapy for graft-versus-host disease (GvHD) prevention after bone marrow transplant. Both patients were obese which may have also contributed to the PTC. Cessation of CsA and combinations of mycophenolate mofetil or tacrolimus and systemic steroids and/or acetazoleamide were effective in managing the symptoms, improving the ocular complications and keeping GvHD asymptomatic. These cases suggest that induction of PTC by CsA used for GvHD prophylaxis in patients undergoing bone marrow transplant is not rare. Physicians who are following patients on CsA need to be alert to the possibility of PTC. Prompt diagnosis followed by thorough evaluation and treatment are crucial for preventing visual loss and improving associated symptoms.

Adolescent↗
PubMed2006

Epidemiologic, socioeconomic, and clinical factors associated with severity of respiratory syncytial virus infection in previously healthy infants.

We prospectively quantified disease severity associated with epidemiologic and socioeconomic parameters as well as the clinical factors in 195 previously healthy infants with confirmed respiratory syncytial virus (RSV) infection. Infants were enrolled into three subgroups according to disease severity: outpatients (82 patients), inpatients (100 patients), and intensive care unit patients (13 patients). Epidemiologic parameters such as gestational age, birth weight, chronologic age at presentation, and gender as well as socioeconomic factors such as ethnic origin, family history of asthma, exposure to cigarette smoke, number of family members, presence of pets at home, breast-feeding, and day-care attendance were not found to predict the severity of RSV illness in previously healthy infants. Our results emphasize the complexity of predicting disease severity in previously healthy infants with RSV infection and suggest that other parameters such as host genetic background might explain the clinical variability.

Cohort Studies↗
PubMed2005

The nuclear-envelope protein and transcriptional repressor LAP2beta interacts with HDAC3 at the nuclear periphery, and induces histone H4 deacetylation.

Nuclear-envelope proteins have been implicated in diverse and fundamental cell functions, among them transcriptional regulation. Gene expression at the territory of the nuclear periphery is known to be repressed by epigenetic modifications such as histone deacetylation and methylation. However, the mechanism by which nuclear-envelope proteins are involved in such modifications is still obscure. We have previously shown that LAP2beta, an integral nuclear-envelope protein that contains the chromatin-binding LEM domain, was able to repress the transcriptional activity of the E2F5-DP3 heterodimer. Here, we show that LAP2beta's repressive activity is more general, encompassing various E2F members as well as other transcription factors such as p53 and NF-kappaB. We further show that LAP2beta interacts at the nuclear envelope with HDAC3, a class-I histone deacetylase, and that TSA (an HDAC inhibitor) abrogates LAP2beta's repressive activity. Finally, we show that LAP2beta is capable of inducing histone-H4 deacetylation. Our data provide evidence for the existence of a previously unknown repressive complex, composed of an integral nuclear membrane protein and a histone modifier, at the nuclear periphery.

Cell Line, Tumor↗
PubMed2005

Nuclear envelopathies--raising the nuclear veil.

The nuclear envelope separates the chromosomes from cytoplasm in eukaryotic cells and consists of three main domains: inner and outer nuclear membranes and nuclear pore complexes. The inner nuclear membrane maintains close associations with the underlying chromatin and nuclear lamina. For many years, the nuclear envelope was thought to function mainly as an architectural stabilizer of the nucleus, participating in assembly and disassembly processes during mitosis. However, recent findings demonstrate that nuclear envelope proteins are involved in fundamental nuclear functions, such as gene transcription and DNA replication, and that inherited or de novo mutated proteins cause human diseases, termed "nuclear envelopathies." These findings emphasize the importance of understanding the functions of this cellular domain, in both physiologic and pathologic states. To date, mutations in the genes encoding the nuclear envelope proteins emerin, MAN1, lamin A/C, and lamin B receptor were found to cause nuclear envelopathies. The diseases that are caused by mutations in LMNA gene are collectively called "laminopathies." Nuclear envelopathies have diverse clinical phenotypes, ranging from cardiac and skeletal myopathies to partial lipodystrophy, peripheral neuropathy, and premature aging. This raises the question of how do such ubiquitously expressed proteins give rise to tissue-specific disease phenotypes. One possible explanation is the involvement of nuclear envelope proteins in the regulation of gene transcription, a novel mechanism that has been the focus of research in our lab in recent years. In this review, we describe recent discoveries in the field of nuclear envelopathies and discuss current proposed pathophysiological mechanisms underlying these diseases.

Animals↗
PubMed2005

Matrix metalloproteinases 2 and 9 are markers of inflammation but not of the degree of fibrosis in chronic hepatitis C.

BACKGROUND: The degree of liver fibrosis and inflammation is important in patients with chronic hepatitis C (CHC) in terms of therapy as well as prognosis. To obviate the need of liver biopsy, serum markers such as procollagen I, III and hyaluronic acid have been proposed but were found to be inaccurate. Controversy still exists regarding the role of matrix metalloproteinases (MMPs) as valid markers of liver fibrosis. AIM: To assess liver and serum MMP-2 and -9 as markers of fibrosis and inflammation in patients with CHC. METHODS: Thirty-five CHC patients and 8 non-hepatitis C patients with normal liver enzymes underwent liver biopsy. Activities of inflammation and fibrosis stage were determined by the Desmet score on a scale of 0-4. Serum and liver tissue MMP-2 and -9 activities were measured by zymography using substrate impregnated gels. RESULTS: Patient and control groups were similar in terms of age (50.8 +/- 15.1 vs. 50.6 +/- 15.2) and male/female ratio (18/17 vs. 4/4). In serum, MMP-9 activity was increased in patients compared to controls (308 +/- 110 vs. 163.5 +/- 35 , p < 0.05). In liver tissue, MMP-9 was also higher in patients than in controls (21 +/- 4.5 vs. 17.1 +/- 5.1, p < 0.05), whereas MMP-2 did not differ between patients and controls. Serum MMP-9 values correlated with liver histologic inflammatory grade (290.4 +/- 83 in grade 2 vs. 562.1 +/- 128 in grade 3, p < 0.05) but not with fibrosis stage. The highest rising in serum MMP-9 levels was observed between grade 2 to grade 3 and was superior to the rising in serum transaminase levels, indicating its advantage in assessing the progression of disease activity. No correlation between liver MMP activities and liver fibrosis or inflammation was observed. CONCLUSION: Serum MMPs, in particular MMP-9, can serve as markers of disease activity rather than fibrosis stage in chronic HCV patients.

Adult↗
PubMed2005

Mutation analysis should be performed to rule out gammac deficiency in children with functional severe combined immune deficiency despite apparently normal immunologic tests.

To study the correlation between genotype and phenotype in x-linked SCID, we have characterized the presentation of 2 unrelated patients. Both had infections suggestive of immunodeficiency, but their immune function and lymphoid tissues were normal. They were found to have an identical R222C mutation in the gammac gene.

Bone Marrow Transplantation↗
PubMed2004

Microarray-based gene expression profiling of hematologic malignancies: basic concepts and clinical applications.

Each cell in our body contains a set of tens of thousands of genes, out of which a set of several thousands determines the cell's characteristics. The deciphering of the sequence of the human genome combined with the technical feasibility to simultaneously measure the gene expression levels of thousands of genes had revolutionized our understanding of cellular processes. This ability has great significance in our comprehension of the mechanisms that bring about diseases in general and hematologic malignancies in particular. Several new high-throughput technologies, commonly referred as microarrays, enable us to perform such measurements and concurrently, bioinformatic and statistical tools were developed to analyze the data obtained by using microarrays. In this review we present examples of analyses of hematologic malignancies using microarrays which contribute to refinement of diagnosis, identification of novel disease subtypes and of relationships between diseases that were previously considered to be unrelated, prediction of response to treatment and identification of genes and pathways linked to pathogenesis, thus defining targets to rational therapy.

Databases as Topic↗
PubMed2004

Histone deacetylase inhibitors--a new tool to treat cancer.

Transcriptional regulation in eukaryotes is a multilevel hierarchical process. It is becoming clear that higher-order chromatin structure, occurring via modifications of histones in their nucleosome structure, plays a crucial role in regulating gene expression, both in normal and pathological states. Deacetylation of histones by histone deacetylases (HDACs) modifies the chromatin from an open gene active euchromatin structure to a closed gene silenced heterochromatin structure. Several cancer promoting mutations and chromosomal translocations result in repression of transcription through abnormal recruitment and activation of HDACs, leading to neoplastic transformation. This is the rationale for the evolvement of HDAC inhibitors as a new class in cancer therapy. Trials have shown anti-proliferation effect of histone deacetylase inhibitors in cell culture, animal models and in human with both hematological and solid tumors. The exact mechanism by which histone deacetylase inhibitors exert their effect is still obscure. Reversal of the alteration in gene expression by fusion transcription factors or overexpressed repressors is just one of several possible explanations. The territory of heterochromatin in the vicinity of the nuclear periphery raised the possibility of involvement of nuclear envelope proteins in the regulation of transcription. Our laboratory is interested in the transcription repression mechanism induced by the nuclear envelope lamina associated polypeptide 2 (LAP2) family of proteins through chromatin modification. Here, we will describe the structure of the nucleosome, review regulation of gene expression by acetylation of histones and give an update on the current phase I and phase II clinical trials with histone deacetylase inhibitors.

Acetylation↗
PubMed2003

Genetic predisposition to infectious pathogens: a review of less familiar variants.

The susceptibility and clinical manifestations of infectious diseases in human populations are influenced by a variety of factors, among them host genetics. Obvious examples for the effect of host genetics on predisposition to unique infections are the primary immunodeficiency diseases. Minor gene variants that influence the host immune system are much more common. The iceberg model can be used to illustrate the epidemiology of immunodeficiency states. Accordingly only a few individuals have known and severe recognized primary immunodeficiencies, whereas many more patients have mild immunodeficiencies that may remain undiagnosed and are predisposed to a unique infectious disease. We review some of the less common variants that influence the host defense and predispose to certain infectious agents or change their outcome.

Animals↗
PubMed2002

[New aspects of celiac disease].

Celiac disease (CD) is an inflammatory condition of the upper small intestine which is caused by gluten ingestion in genetically susceptible patients. Over the past few years, significant changes have occurred in our understanding of CD in terms of patterns of disease expression, pathological manifestations, associated diseases, definition of high-risk patients, screening policy and diagnosis, and epidemiological, genetic, immunological and pathogenetic aspects. We review new perspectives of CD in order to enhance the familiarity of physicians with a disease that is now considered to be more common than was thought in the past.

Adult↗
PubMed2002

Celiac disease: extraintestinal manifestations, associated diseases, and complications.

The aim of this chapter is to increase the familiarity of physicians with conditions or complications associated with CD, a disease that is more common than had been thought in the past. The differentiation between atypical manifestations, associated disease, and complications of CD is not always clear. With careful adherence to the necessary dietary restrictions, patients with CD can remain relatively free of troublesome symptoms, their long-term prognosis is excellent, and most complications can be prevented. (24) Indeed, 5-year survival rates of patients with CD did not differ from those in the general population. (6) This review emphasizes the importance of a screening policy for silent CD, justified on the basis of later developing complications such as malignancy, development of low bone mineral density, risk of neurologic abnormalities, and associated diseases, which may be preventable by GFD.

Celiac Disease↗