miR-181b negatively regulates activation-induced cytidine deaminase in B cells

Single‐molecule methods, activation‐induced cytidine deaminase, and quantum mechanical approach to explore and prevent carcinogenesis

Recent advancements in single‐molecule methods have not only made it possible to obtain precise measurements for complex biological processes but also to produce simple mathematical models for intricate biochemical mechanisms, which would otherwise be speculative. These developments have strengthened our ability to respond through mathematical modeling to concepts of protein‒protein and protein‒DNA interactions on a nanometer level and address‐related questions. In this article, we examine an intriguing biological phenomenon in which a protein and an enzyme co‐jointly encounter carcinogenic adducts during transcription. We are focusing mainly on the dysregulation of the protein involved and the possible consequences that may arise. By providing a quantum mechanical model, we have demonstrated that the presence of carcinogenic adducts in a transcriptional bubble deregulates the protein that could cause lethal mutations. Next, we present a case study to explore carcinogenesis by suggesting an alternative experimental design. Our quantum mechanical model emphasizes the use of a quantized energies approach for specific mechanisms within the living cells. Radiation‐induced carcinogenicity can be prevented if radiation interacting with tissue is not given the energies that satisfy the quantization conditions.

miRNA Biology in Chronic Lymphocytic Leukemia

microRNAs (miRNAs) are a class of small non-coding RNAs that play a crucial regulatory role in fundamental biological processes and have been implicated in various diseases, including cancer. The first evidence of the cancer-related function of miRNAs was discovered in chronic lymphocytic leukemia (CLL) in the early 2000s. Alterations in miRNA expression have since been shown to strongly influence the clinical course, prognosis, and response to treatment in patients with CLL. Therefore, the identification of specific miRNA alterations not only enhances our understanding of the molecular mechanisms underlying CLL but also holds promise for the development of novel diagnostic and therapeutic strategies. This review aims to provide a comprehensive summary of the current knowledge and recent insights into miRNA dysregulation in CLL, emphasizing its pivotal roles in disease progression, including the development of the lethal Richter syndrome, and to provide an update on the latest translational research in this field.

AID in non-Hodgkin B-cell lymphomas: The consequences of on- and off-target activity

Activation induced cytidine deaminase (AID) is a key element of the adaptive immune system, required for immunoglobulin isotype switching and affinity maturation of B-cells as they undergo the germinal center (GC) reaction in peripheral lymphoid tissue. The inherent DNA damaging activity of this enzyme can also have off-target effects in B-cells, producing lymphomagenic chromosomal translocations that are characteristic features of various classes of non-Hodgkin B-cell lymphoma (B-NHL), and generating oncogenic mutations, so-called aberrant somatic hypermutation (aSHM). Additionally, AID has been found to affect gene expression through demethylation as well as altered interactions between gene regulatory elements. These changes have been most thoroughly studied in B-NHL arising from GC B-cells. Here, we describe the most common classes of GC-derived B-NHL and explore the consequences of on- and off-target AID activity in B and plasma cell neoplasms. The relationships between AID expression, including effects of infection and other exposures/agents, mutagenic activity and lymphoma biology are also discussed.

The role of miRNAs in Behçet's disease

The symptoms of Behçet's disease (BD), a multisystemic condition with autoimmune and inflammation as hallmarks, include arthritis, recurring oral and vaginal ulcers, skin rashes and lesions, and involvement of the nervous, gastrointestinal, and vascular systems. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), may be important regulators of inflammation and autoimmune disease. These ncRNAs are essential to the physiological and pathophysiological disease course, and miRNA in particular has received significant attention for its role and function in BD and its potential use as a diagnostic biomarker in recent years. Although promising as therapeutic targets, miRNAs must be studied further to fully comprehend how miRNAs in BD act biologically.

Role of the mechanisms for antibody repertoire diversification in monoclonal light chain deposition disorders: when a friend becomes foe

The adaptive immune system of jawed vertebrates generates a highly diverse repertoire of antibodies to meet the antigenic challenges of a constantly evolving biological ecosystem. Most of the diversity is generated by two mechanisms: V(D)J gene recombination and somatic hypermutation (SHM). SHM introduces changes in the variable domain of antibodies, mostly in the regions that form the paratope, yielding antibodies with higher antigen binding affinity. However, antigen recognition is only possible if the antibody folds into a stable functional conformation. Therefore, a key force determining the survival of B cell clones undergoing somatic hypermutation is the ability of the mutated heavy and light chains to efficiently fold and assemble into a functional antibody. The antibody is the structural context where the selection of the somatic mutations occurs, and where both the heavy and light chains benefit from protective mechanisms that counteract the potentially deleterious impact of the changes. However, in patients with monoclonal gammopathies, the proliferating plasma cell clone may overproduce the light chain, which is then secreted into the bloodstream. This places the light chain out of the protective context provided by the quaternary structure of the antibody, increasing the risk of misfolding and aggregation due to destabilizing somatic mutations. Light chain-derived (AL) amyloidosis, light chain deposition disease (LCDD), Fanconi syndrome, and myeloma (cast) nephropathy are a diverse group of diseases derived from the pathologic aggregation of light chains, in which somatic mutations are recognized to play a role. In this review, we address the mechanisms by which somatic mutations promote the misfolding and pathological aggregation of the light chains, with an emphasis on AL amyloidosis. We also analyze the contribution of the variable domain (V_L) gene segments and somatic mutations on light chain cytotoxicity, organ tropism, and structure of the AL fibrils. Finally, we analyze the most recent advances in the development of computational algorithms to predict the role of somatic mutations in the cardiotoxicity of amyloidogenic light chains and discuss the challenges and perspectives that this approach faces.

MicroRNAs and Periodontal Disease: Helpful Therapeutic Targets?

Periodontal disease is the most common oral disease. This disease can be considered as an inflammatory disease. The immune response to bacteria accumulated in the gum line plays a key role in the pathogenesis of periodontal disease. In addition to immune cells, periodontal ligament cells and gingival epithelial cells are also involved in the pathogenesis of this disease. miRNAs which are small RNA molecules with around 22 nucleotides have a considerable relationship with the immune system affecting a wide range of immunological events. These small molecules are also in relation with periodontium tissues especially periodontal ligament cells. Extensive studies have been performed in recent years on the role of miRNAs in the pathogenesis of periodontal disease. In this review paper, we have reviewed the results of these studies and discussed the role of miRNAs in the immunopathogenesis of periodontal disease comprehensively. miRNAs play an important role in the pathogenesis of periodontal disease and maybe helpful therapeutic targets for the treatment of periodontal disease.

Activation induced cytidine deaminase: An old friend with new faces

Activation induced cytidine deaminase (AID) protein is a member of APOBEC family. AID converts cytidine to uracil, which is a key step for somatic hypermutation (SHM) and class switch recombination (CSR). AID also plays critical roles in B cell precursor stages, removing polyreactive B cells from immune repertoire. Since the main function of AID is inducing point mutations, dysregulation can lead to increased mutation load, translocations, disturbed genomic integrity, and lymphomagenesis. As such, expression of AID as well as its function is controlled strictly at various molecular steps. Other members of the APOBEC family also play crucial roles during carcinogenesis. Considering all these functions, AID represents a bridge, linking chronic inflammation to carcinogenesis and immune deficiencies to autoimmune manifestations.

Aberrant B Cell Signaling in Autoimmune Diseases

Aberrant B cell signaling plays a critical in role in various systemic and organ-specific autoimmune diseases. This is supported by genetic evidence by many functional studies in B cells from patients or specific animal models and by the observed efficacy of small-molecule inhibitors. In this review, we first discuss key signal transduction pathways downstream of the B cell receptor (BCR) that ensure that autoreactive B cells are removed from the repertoire or functionally silenced. We provide an overview of aberrant BCR signaling that is associated with inappropriate B cell repertoire selection and activation or survival of peripheral B cell populations and plasma cells, finally leading to autoantibody formation. Next to BCR signaling, abnormalities in other signal transduction pathways have been implicated in autoimmune disease. These include reduced activity of several phosphates that are downstream of co-inhibitory receptors on B cells and increased levels of BAFF and APRIL, which support survival of B cells and plasma cells. Importantly, pathogenic synergy of the BCR and Toll-like receptors (TLR), which can be activated by endogenous ligands, such as self-nucleic acids, has been shown to enhance autoimmunity. Finally, we will briefly discuss therapeutic strategies for autoimmune disease based on interfering with signal transduction in B cells.

Hypoxia and hypoxia-inducible factor signals regulate the development, metabolism, and function of B cells

Hypoxia is a common hallmark of healthy tissues in physiological states or chronically inflamed tissues in pathological states. Mammalian cells sense and adapt to hypoxia mainly through hypoxia-inducible factor (HIF) signaling. Many studies have shown that hypoxia and HIF signaling play an important regulatory role in development and function of innate immune cells and T cells, but their role in B cell biology is still controversial. B cells experience a complex life cycle (including hematopoietic stem cells, pro-B cells, pre-B cells, immature B cells, mature naïve B cells, activated B cells, plasma cells, and memory B cells), and the partial pressure of oxygen (PO2) in the corresponding developmental niche of stage-specific B cells is highly dynamic, which suggests that hypoxia and HIF signaling may play an indispensable role in B cell biology. Based on the fact that hypoxia niches exist in the B cell life cycle, this review focuses on recent discoveries about how hypoxia and HIF signaling regulate the development, metabolism, and function of B cells, to facilitate a deep understanding of the role of hypoxia in B cell-mediated adaptive immunity and to provide novel strategies for vaccine adjuvant research and the treatment of immunity-related or infectious diseases.

MicroRNA-regulated B cells in obesity

Obesity is a prevalent health risk by inducing chronic, low-grade inflammation and insulin resistance, in part from adipose tissue inflammation perpetuated by activated B cells and other resident immune cells. However, regulatory mechanisms controlling B-cell actions in adipose tissue remain poorly understood, limiting therapeutic innovations. MicroRNAs are potent regulators of immune cell dynamics through fine-tuning a network of downstream genes in multiple signaling pathways. In particular, miR-150 is crucial to B-cell development and suppresses obesity-associated inflammation via regulating adipose tissue B-cell function. Herein, we review the effect of microRNAs on B-cell development, activation, and function and highlight miR-150-regulated B-cell actions during obesity which modulate systemic inflammation and insulin resistance. In this way, we hope to promote translational discoveries that mitigate obesity-induced health risks by targeting microRNA-regulated B-cell actions.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

Identification and Contribution of Inflammation-Induced Novel MicroRNA in the Pathogenesis of Systemic Lupus Erythematosus

Recently microRNAs (miRNAs) have been recognized as powerful regulators of many genes and pathways involved in the pathogenesis of inflammatory diseases including Systemic Lupus Erythematosus (SLE). SLE is an autoimmune disease characterized by production of various autoantibodies, inflammatory immune cells, and dysregulation of epigenetic changes. Several candidate miRNAs regulating inflammation and autoimmunity in SLE are described. In this study, we found significant increases in the expression of miR21, miR25, and miR186 in peripheral blood mononuclear cells (PBMCs) of SLE patients compared to healthy controls. However, miR146a was significantly decreased in SLE patients compared to healthy controls and was negatively correlated with plasma estradiol levels and with SLE disease activity scores (SLEDAI). We also found that protein levels of IL-12 and IL-21 were significantly increased in SLE patients as compared to healthy controls. Further, our data shows that protein levels of IL-12 were positively correlated with miR21 expression and protein levels of IL-21 positively correlated with miR25 and miR186 expression in SLE patients. In addition, we found that levels of miR21, miR25, and miR186 positively correlated with SLEDAI and miR146a was negatively correlated in SLE patients. Thus, our data shows a dynamic interplay between disease pathogenesis and miRNA expression. This study has translational potential and may identify novel therapeutic targets in patients with SLE.

Effect of microRNA-181b on the biological characteristics and clinical drug resistance of small-cell lung cancer by targeting angiotensin converting enzyme 2

Objective

To clarify the effect of miR‐181b on the biological function of small‐cell lung cancer (SCLC) and explore the effect of clinical resistance on SCLC.

Methods

Blood samples were collected from 30 SCLC patients and 30 non‐SCLC patients in our department from 2017 to 2019 to detect the expression level of miR‐181b.The expression level of miR‐181b was detected in SCLC cells by RT‐PCR, and screening of downstream target genes by gene chip, verification with luciferase, and Western blotting. In addition, collect the general data of 30 SCLC patients and 30 non‐SCLC patients (control group), the patients were diagnosed by pathology and undergoing EC protocol in the Department of Thoracic Surgery and Oncology of our hospital to detect the expression level of mir‐181b in different periods. Furthermore, in the SCLC cell line, EC chemotherapy was administered to detect the sensitivity of drug resistance and nondrug resistance.

Results

miR‐181b in SCLC patients was lower than in normal people as well as the drug‐sensitive cell line. ACE2 was verified as a downstream target of miR‐181b by gene chip screening. First‐line chemotherapy can promote the recovery of miR‐181b, but cannot repair to normal levels. miR‐181b can enhance the drug sensitivity of SCLC drug‐resistant cells.

Conclusion

miR‐181b directly targets ACE2 to affect the biological characteristics of SCLC. The expression level of miR‐181b is highly related to the drug resistance of SCLC, which suggests that miR‐181b could be a potential biomarker candidate for treatment efficacy of SCLC.

USP10 regulates B cell response to SARS-CoV-2 or HIV-1 nanoparticle vaccines through deubiquitinating AID

Activation-induced cytidine deaminase (AID) initiates class-switch recombination and somatic hypermutation (SHM) in antibody genes. Protein expression and activity are tightly controlled by various mechanisms. However, it remains unknown whether a signal from the extracellular environment directly affects the AID activity in the nucleus where it works. Here, we demonstrated that a deubiquitinase USP10, which specifically stabilizes nuclear AID protein, can translocate into the nucleus after AKT-mediated phosphorylation at its T674 within the NLS domain. Interestingly, the signals from BCR and TLR1/2 synergistically promoted this phosphorylation. The deficiency of USP10 in B cells significantly decreased AID protein levels, subsequently reducing neutralizing antibody production after immunization with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or human immunodeficiency virus type 1 (HIV-1) nanoparticle vaccines. Collectively, we demonstrated that USP10 functions as an integrator for both BCR and TLR signals and directly regulates nuclear AID activity. Its manipulation could be used for the development of vaccines and adjuvants.

MicroRNA-directed pathway discovery elucidates an miR-221/222-mediated regulatory circuit in class switch recombination

MicroRNAs (miRNAs, miRs) regulate cell fate decisions by post-transcriptionally tuning networks of mRNA targets. We used miRNA-directed pathway discovery to reveal a regulatory circuit that influences Ig class switch recombination (CSR). We developed a system to deplete mature, activated B cells of miRNAs, and performed a rescue screen that identified the miR-221/222 family as a positive regulator of CSR. Endogenous miR-221/222 regulated B cell CSR to IgE and IgG1 in vitro, and miR-221/222-deficient mice exhibited defective IgE production in allergic airway challenge and polyclonal B cell activation models in vivo. We combined comparative Ago2-HITS-CLIP and gene expression analyses to identify mRNAs bound and regulated by miR-221/222 in primary B cells. Interrogation of these putative direct targets uncovered functionally relevant downstream genes. Genetic depletion or pharmacological inhibition of Foxp1 and Arid1a confirmed their roles as key modulators of CSR to IgE and IgG1.

Human and herpesvirus microRNAs in periodontal disease

Periodontitis is a multi-etiologic infection characterized clinically by pathologic loss of the periodontal ligament and alveolar bone. Herpesviruses and specific bacterial species are major periodontal pathogens that cooperate synergistically in producing severe periodontitis. Cellular immunity against herpesviruses and humoral immunity against bacteria are key periodontal host defenses. Genetic, epigenetic, and environmental factors are modifiers of periodontal disease severity. MicroRNAs are a class of noncoding, gene expression-based, posttranscriptional regulatory RNAs of great importance for maintaining tissue homeostasis. Aberrant expression of microRNAs has been associated with several medical diseases. Periodontal tissue cells and herpesviruses elaborate several microRNAs that are of current research interest. This review attempts to conceptualize the role of periodontal microRNAs in the pathogenesis of periodontitis. The diagnostic potential of salivary microRNAs is also addressed. Employment of microRNA technology in periodontics represents an interesting new preventive and therapeutic possibility.

Non-Coding RNAs in Normal B-Cell Development and in Mantle Cell Lymphoma: From Molecular Mechanism to Biomarker and Therapeutic Agent Potential

B-lymphocytes are essential for an efficient immune response against a variety of pathogens. A large fraction of hematologic malignancies are of B-cell origin, suggesting that the development and activation of B cells must be tightly regulated. In recent years, differentially expressed non-coding RNAs have been identified in mantle cell lymphoma (MCL) tumor samples as opposed to their naive, normal B-cell compartment. These aberrantly expressed molecules, specifically microRNAs (miRNAs), circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), have a role in cellular growth and survival pathways in various biological models. Here, we provide an overview of current knowledge on the role of non-coding RNAs and their relevant targets in B-cell development, activation and malignant transformation, summarizing the current understanding of the role of aberrant expression of non-coding RNAs in MCL pathobiology with perspectives for clinical use.

Dysregulated translational factors and epigenetic regulations orchestrate in B cells contributing to autoimmune diseases

B cells play a crucial role in antigen presentation, antibody production and pro-/anti-inflammatory cytokine secretion in adaptive immunity. Several translational factors including transcription factors and cytokines participate in the regulation of B cell development, with the cooperation of epigenetic regulations. Autoimmune diseases are generally characterized with autoreactive B cells and high-level pathogenic autoantibodies. The success of B cell depletion therapy in mouse model and clinical trials has proven the role of B cells in pathogenesis of autoimmune diseases. The failure of B cell tolerance in immune checkpoints results in accumulated autoreactive naïve B (B_N) cells with aberrant B cell receptor signaling and dysregulated B cell response, contributing to self-antibody-mediated autoimmune reaction. Dysregulation of translational factors and epigenetic alterations in B cells has been demonstrated to correlate with aberrant B cell compartment in autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis, primary Sjögren's syndrome, multiple sclerosis, diabetes mellitus and pemphigus. This review is intended to summarize the interaction of translational factors and epigenetic regulations that are involved with development and differentiation of B cells, and the mechanism of dysregulation in the pathogenesis of autoimmune diseases.

Epigenetic linkage of systemic lupus erythematosus and nutrition

The term "epigenetics" refers to a series of meiotically/mitotically inheritable alterations in gene expression, related to environmental factors, without disruption on DNA sequences of bases. Recently, the pathophysiology of autoimmune diseases (ADs) has been closely linked to epigenetic modifications. Actually, epigenetic mechanisms can modulate gene expression or repression of targeted cells and tissues involved in autoimmune/inflammatory conditions acting as keys effectors in regulation of adaptive and innate responses. ADs, as systemic lupus erythematosus (SLE), a rare disease that still lacks effective treatment, is characterized by epigenetic marks in affected cells.Taking into account that epigenetic mechanisms have been proposed as a winning strategy in the search of new more specific and personalized therapeutics agents. Thus, pharmacology and pharmacoepigenetic studies about epigenetic regulations of ADs may provide novel individualized therapies. Focussing in possible implicated factors on development and predisposition of SLE, diet is feasibly one of the most important factors since it is linked directly to epigenetic alterations and these epigenetic changes may augment or diminish the risk of SLE. Nevertheless, several studies have guaranteed that dietary therapy could be a promise to SLE patients via prophylactic actions deprived of side effects of pharmacology, decreasing co-morbidities and improving lifestyle of SLE sufferers.Herein, we review and discuss the cross-link between epigenetic mechanisms on SLE predisposition and development, as well as the influence of dietary factors on regulation epigenetic modifications that would eventually make a positive impact on SLE patients.

AID in Chronic Lymphocytic Leukemia: Induction and Action During Disease Progression

The enzyme activation-induced cytidine deaminase (AID) initiates somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin (Ig) genes, critical actions for an effective adaptive immune response. However, in addition to the benefits generated by its physiological roles, AID is an etiological factor for the development of human and murine leukemias and lymphomas. This review highlights the pathological role of AID and the consequences of its actions on the development, progression, and therapeutic refractoriness of chronic lymphocytic leukemia (CLL) as a model disease for mature lymphoid malignancies. First, we summarize pertinent aspects of the expression and function of AID in normal B lymphocytes. Then, we assess putative causes for AID expression in leukemic cells emphasizing the role of an activated microenvironment. Thirdly, we discuss the role of AID in lymphomagenesis, in light of recent data obtained by NGS analyses on the genomic landscape of leukemia and lymphomas, concentrating on the frequency of AID signatures in these cancers and correlating previously described tumor-gene drivers with the presence of AID off-target mutations. Finally, we discuss how these changes could affect tumor suppressor and proto-oncogene targets and how they could be associated with disease progression. Collectively, we hope that these sections will help to better understand the complex paradox between the physiological role of AID in adaptive immunity and its potential causative activity in B-cell malignancies.

microRNA Fine-Tuning of the Germinal Center Response

Germinal centers (GCs) are complex multicellular structures in which antigen-specific B cells undergo the molecular remodeling that enables the generation of high-affinity antibodies and the differentiation programs that lead to the generation of plasma–antibody-secreting cells and memory B cells. These reactions are tightly controlled by a variety of mechanisms, including the post-transcriptional control of gene expression by microRNAs (miRNAs). Through the development of animal models with B cell-specific modified miRNA expression, we have contributed to the understanding of the role of miRNAs in the regulation of GC responses and in B cell neoplasia. Here, we review recent advances in the understanding of the role of miRNAs in the regulation of B cell and T follicular helper physiology during the GC response and in the diseases associated to GC response dysregulation.

The Multifaceted Role and Utility of MicroRNAs in Indolent B-Cell Non-Hodgkin Lymphomas

Normal B-cell development is a tightly regulated complex procedure, the deregulation of which can lead to lymphomagenesis. One common group of blood cancers is the B-cell non-Hodgkin lymphomas (NHLs), which can be categorized according to the proliferation and spread rate of cancer cells into indolent and aggressive ones. The most frequent indolent B-cell NHLs are follicular lymphoma and marginal zone lymphoma. MicroRNAs (miRNAs) are small non-coding RNAs that can greatly influence protein expression. Based on the multiple interactions among miRNAs and their targets, complex networks of gene expression regulation emerge, which normally are essential for proper B-cell development. Multiple miRNAs have been associated with B-cell lymphomas, as the deregulation of these complex networks can lead to such pathological states. The aim of the present review is to summarize the existing information regarding the multifaceted role of miRNAs in indolent B-cell NHLs, affecting the main B-cell subpopulations. We attempt to provide insight into their biological function, the complex miRNA-mRNA interactions, and their biomarker utility in these malignancies. Lastly, we address the limitations that hinder the investigation of the role of miRNAs in these lymphomas and discuss ways that these problems could be overcome in the future.

Non-coding RNAs (miRNAs and lncRNAs) and their roles in lymphogenesis in all types of lymphomas and lymphoid malignancies

Contemporary developments in molecular biology have been combined with discoveries on the analysis of the role of all non-coding RNAs (ncRNAs) in human diseases, particularly in cancer, by examining their roles in cells. Currently, included among these common types of cancer, are all the lymphomas and lymphoid malignancies, which represent a diverse group of neoplasms and malignant disorders. Initial data suggest that non-coding RNAs, particularly long ncRNAs (lncRNAs), play key roles in oncogenesis and that lncRNA-mediated biology is an important key pathway to cancer progression. Other non-coding RNAs, termed microRNAs (miRNAs or miRs), are very promising cancer molecular biomarkers. They can be detected in tissues, cell lines, biopsy material and all biological fluids, such as blood. With the number of well-characterized cancer-related lncRNAs and miRNAs increasing, the study of the roles of non-coding RNAs in cancer is bringing forth new hypotheses of the biology of cancerous cells. For the first time, to the best of our knowledge, the present review provides an up-to-date summary of the recent literature referring to all diagnosed ncRNAs that mediate the pathogenesis of all types of lymphomas and lymphoid malignancies.

HIF-1α and miR-210 differential and lineage-specific expression in systemic lupus erythematosus

Systemic lupus erythematosus (SLE, lupus) is a chronic autoimmune disease characterized by loss of peripheral tolerance to nuclear self-antigens. It is increasingly recognized that aberrant T cell metabolism is a critical mediator of SLE immunopathology. Hypoxia inducible factor 1⍺ (HIF-1α) is a key transcription factor that regulates T cell metabolism in response to immune stimuli. T cell activation induces HIF-1α expression and transcriptional activation of HIF-responsive genes. HypoxamiRs are a group of microRNAs sensitive to HIF-1α transcriptional regulation that function to fine-tune the HIF-driven transcriptional program. The 'master' hypoxamiR, miR-210 is transcriptionally regulated by HIF-1α and negatively regulates HIF-1α activity. Although a key role for HIF-1α in has been described in a number of autoimmune and inflammatory diseases and abnormal microRNA expression profiles correlate with poor clinical outcome in a number of rheumatologic diseases, the expression and function of HIF-1α and miR-210 in lupus remains largely uncharacterized. Here we report HIF-1α and miR-210 differential and lineage-specific expression in systemic lupus erythematosus. We show that HIF-1α mRNA and protein is overexpressed in human lupus CD4⁺ cells but not in CD8⁺ or CD19⁺ cells. RORγt, was upregulated in human lupus lymphocytes while FoxP3 expression remained unchanged. We show that miR-210 expression in lupus-prone mice correlates with disease activity and is robustly and selectively upregulated in CD4⁺ cells from both human lupus patients and lupus-prone mice. Our results suggest that abnormal HIF-1α and miR-210 expression contributes to SLE immune pathology and that HIF-1α/miR-210 may represent a novel and important regulatory axis in SLE.

Noncoding RNAs in B cell responses

B cells constitute a main branch adaptive immune system. They mediate host defence through the production of high-affinity antibodies against an enormous diversity of foreign antigens. Remarkably, B cells undergo multiple types of somatic DNA mutation to achieve this effector function, including class switch recombination (CSR) and somatic hypermutation (SHM). These processes occur in response to antigen recognition and inflammatory signals, and require strict biological control at multiple levels. Transcription within the locus that encodes antibodies plays direct roles in CSR. Additional non-coding RNAs (ncRNAs), including both microRNAs (miRNAs) and long ncRNAs (lncRNAs), also play pivotal roles in B cell activation and terminal effector function through post-transcriptional gene regulation and chromatin remodelling, respectively.

MicroRNA control of B cell tolerance, autoimmunity and cancer

Since the discovery of the first microRNA (miRNA) in 1993, thousands of miRNAs have been identified in humans and mice and many of them have been shown to control a large variety of cellular processes in different cell types including those composing the immune system. MicroRNAs regulate virtually all aspects of immune cell development, differentiation and function. Studies have shown that these molecules are involved in the maintenance of lymphocyte tolerance and, when dysregulated, promote the development of autoimmune diseases. In this review, we focus on the current knowledge about the roles of miRNAs in B cell tolerance and their contribution to autoimmunity, highlighting additional roles for some of these miRNAs in T cell tolerance. Finally, we will comment on miRNAs that promote both autoimmunity and lymphoma.

Epigenetics of the antibody and autoantibody response

B cell differentiation driven by microbial antigens leads to production of anti-microbial antibodies, such as those neutralizing viruses, bacteria or bacterial toxin, that are class-switched (IgG and IgA) and somatically hypermutated (maturation of the antibody response) as well as secreted in large volume by plasma cells. Similar features characterize pathogenic antibodies to self-antigens in autoimmunity, reflecting the critical role of class switch DNA recombination (CSR), somatic hypermutation (SHM) and plasma cell differentiation in the generation of antibodies to not only foreign antigens but also self-antigens (autoantibodies). Central to CSR/SHM and plasma cell differentiation are AID, a potent DNA cytidine deaminase encoded by Aicda, and Blimp-1, a transcription factor encoded by Prdm1. B cell-intrinsic expression of Aicda and Prdm1 is regulated by epigenetic elements and processes, including DNA methylation, histone post-translational modifications and non-coding RNAs, particularly miRNAs. Here, we will discuss: B cell-intrinsic epigenetic processes that regulate antibody and autoantibody responses; how epigenetic dysregulation alters CSR/SHM and plasma cell differentiation, thereby leading to autoantibody responses, as in systemic lupus; and, how these can be modulated by nutrients, metabolites, and hormones through changes in B cell-intrinsic epigenetic mechanisms, which can provide therapeutic targets in autoimmunity.

The Role of Noncoding RNAs in B-Cell Lymphoma

In recent years, emerging evidence has suggested that noncoding RNAs (ncRNAs) participate in nearly every aspect of biological processes and play a crucial role in the genesis and progression of numerous tumors, including B-cell lymphoma. The exploration of ncRNA dysregulations and their functions in B-cell lymphoma provides new insights into lymphoma pathogenesis and is essential for indicating future clinical trials and optimizing the diagnostic and therapeutic strategies. In this review, we summarize the role of ncRNAs in B-cell lymphoma and discuss their potential in clinical applications.

Unfolding the Role of Splicing Factors and RNA Debranching in AID Mediated Antibody Diversification

Activated B-cells diversify their antibody repertoire via somatic hypermutation (SHM) and class switch recombination (CSR). SHM is restricted to the variable region, whereas, CSR is confined to the constant region of immunoglobulin (Ig) genes. Activation-induced cytidine deaminase (AID) is a crucial player in the diversification of antibodies in the activated B-cell. AID catalyzes the deamination of cytidine (C) into uracil (U) at Ig genes. Subsequently, low fidelity repair of U:G mismatches may lead to mutations. Transcription is essential for the AID action, as it provides a transient single-strand DNA substrate. Since splicing is a co-transcriptional event, various splicing factors or regulators influence the transcription. Numerous splicing factors are known to regulate the AID targeting, function, Ig transcription, and AID splicing, which eventually influence antibody diversification processes. Splicing regulator SRSF1-3, a splicing isoform of serine arginine-rich splicing factor (SRSF1), and CTNNBL1, a spliceosome interacting factor, interact with AID and play a critical role in SHM. Likewise, a splicing regulator polypyrimidine tract binding protein-2 (PTBP2) and the debranching enzyme (DBR1) debranches primary switch transcripts which later forms G-quadruplex structures, and the S region guide RNAs direct AID to S region DNA. Moreover, AID shows several alternate splicing isoforms, like AID devoid of exon-4 (AIDΔE4) that is expressed in various pathological conditions. Interestingly, RBM5, a splicing regulator, is responsible for the skipping of AID exon 4. In this review, we discuss the role and significance of splicing factors in the AID mediated antibody diversification.

Activation-induced cytidine deaminase: in sickness and in health

Activation Induced cytidine Deaminase (AID) is an essential enzyme of the adaptive immune system. Its canonical activity is restricted to B lymphocytes, playing an essential role in the diversification of antibodies by enhancing specificity and changing affinity. This is possible through its DNA deaminase function, leading to mutations in DNA. In the last decade, AID has been assigned an additional function: that of a powerful DNA demethylator. Adverse cellular conditions such as chronic inflammation can lead to its deregulation and overexpression. It is an important driver of B-cell lymphoma due to its natural ability to modify DNA through deamination, leading to mutations and epigenetic changes. However, the deregulation of AID is not restricted to lymphoid cells. Recent findings have provided new insights into the role that this protein plays in the development of non-lymphoid cancers, with some research shedding light on novel AID-driven mechanisms of cellular transformation. In this review, we provide an updated narrative of the normal physiological functions of AID. Additionally, we review and discuss the recent research studies that have implicated AID in carcinogenesis in varying tissue types including lymphoid and non-lymphoid cancers. We review the mechanisms, whereby AID promotes carcinogenesis and highlight important areas of future research.

The Multiple Roles of Hepatitis B Virus X Protein (HBx) Dysregulated MicroRNA in Hepatitis B Virus-Associated Hepatocellular Carcinoma (HBV-HCC) and Immune Pathways

Currently, the treatment of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) [HBV-HCC] relies on blunt tools that are unable to offer effective therapy for later stage pathogenesis. The potential of miRNA to treat HBV-HCC offer a more targeted approach to managing this lethal carcinoma; however, the complexity of miRNA as an ancillary regulator of the immune system remains poorly understood. This review examines the overlapping roles of HBx-dysregulated miRNA in HBV-HCC and immune pathways and seeks to demonstrate that specific miRNA response in immune cells is not independent of their expression in hepatocytes. This interplay between the two pathways may provide us with the possibility of using candidate miRNA to manipulate this interaction as a potential therapeutic option.

microRNA-181 serves as a dual-role regulator in the development of human cancers

MicroRNAs (miRNAs) as the regulatory short noncoding RNAs are involved in a wide array of cellular and molecular processes. They negatively regulate gene expression and their dysfunction is correlated with cancer development through modulation of multiple signaling pathways. Therefore, these molecules could be considered as novel biomarkers and therapeutic targets for more effective management of human cancers. Recent studies have demonstrated that the miR-181 family is dysregulated in various tumor tissues and plays a pivotal role in carcinogenesis. They have been shown to act as oncomirs or tumor suppressors considering their mRNA targets and to be involved in cell proliferation, apoptosis, autophagy, angiogenesis and drug resistance. Additionally, these miRNAs have been demonstrated to exert their regulatory effects through modulating multiple signaling pathways including PI3K/AKT, MAPK, TGF-b, Wnt, NF-κB, Notch pathways. Given that, in this review, we briefly summarise the recent studies that have focused on the roles of miRNA-181 family as the multifunctional miRNAs in tumorigenesis and cancer development. These miRNAs may serve as diagnostic and prognostic biomarkers or therapeutic targets in human cancer gene therapy.

The impact of microRNAs on alterations of gene regulatory networks in allergic diseases

Allergic diseases including asthma are worldwide on the rise and contribute significantly to health expenditures. Allergic diseases are prototypic diseases with a strong gene by environment interaction component and epigenetic mechanisms might mediate the effects of the environment on the disease phenotype. MicroRNAs, small non-coding RNAs (miRNAs), regulate gene expression post-transcriptionally. Functional single-stranded miRNAs are generated in multiple steps of enzymatic processing from their precursors and mature miRNAs are included into the RNA-induced silencing complex (RISC). They imperfectly base-pair with the 3'UTR region of targeted genes leading to translational repression or mRNA decay. The cellular context and microenvironment as well the isoform of the mRNA control the dynamics and complexity of the regulatory circuits induced by miRNAs that regulate cell fate decisions and function. MiR-21, miR-146a/b and miR-155 are among the best understood miRNAs of the immune system and implicated in different diseases including allergic diseases. MiRNAs are implicated in the induction of the allergy reinforcing the Th2 phenotype (miR-19a, miR-24, miR-27), while other miRNAs promote regulatory T cells associated with allergen tolerance or unresponsiveness. In the current chapter we describe in detail the biogenesis and regulatory function of miRNAs and summarize current knowledge on miRNAs in allergic diseases and allergy relevant cell fate decisions focusing mainly on immune cells. Furthermore, we evoke the principles of regulatory loops and feedback mechanisms involving miRNAs on examples with relevance for allergic diseases. Finally, we show the potential of miRNAs and exosomes containing miRNAs present in several biological fluids that can be exploited with non-invasive procedures for diagnostic and potentially therapeutic purposes.

The epigenetic face of lupus: Focus on antigen-presenting cells

In recent years, epigenetic mechanisms became widely known due to their ability to regulate and maintain physiological processes such as cell growth, development, differentiation and genomic stability. When dysregulated, epigenetic mechanisms, may introduce gene expression changes and disturbance in immune homeostasis leading to autoimmune diseases. Systemic lupus erythematosus (SLE), the most extensively studied autoimmune disorder, has already been correlated with epigenetic modifications, especially in T cells. Since these cell rely on antigen presentation, it may be assumed that erroneous activity of antigen-presenting cells (APCs), culminates in T cell abnormalities. In this review we summarize and discuss the epigenetic modifications in SLE affected APCs, with the focus on dendritic cells (DCs), B cells and monocytes. Unravelling this aspect of SLE pathogenesis, might result in identification of new disease biomarkers and putative therapeutic approaches.

The Epigenetics of Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a life-threatening autoimmune disease that is characterized by dysregulated dendritic cells, T and B cells, and abundant autoantibodies. The pathogenesis of lupus remains unclear. However, increasing evidence has shown that environment factors, genetic susceptibilities, and epigenetic regulation contribute to abnormalities in the immune system. In the past decades, several risk gene loci have been identified, such as MHC and C1q. However, genetics cannot explain the high discordance of lupus incidence in homozygous twins. Environmental factor-induced epigenetic modifications on immune cells may provide some insight. Epigenetics refers to inheritable changes in a chromosome without altering DNA sequence. The primary mechanisms of epigenetics include DNA methylation, histone modifications, and non-coding RNA regulations. Increasing evidence has shown the importance of dysregulated epigenetic modifications in immune cells in pathogenesis of lupus, and has identified epigenetic changes as potential biomarkers and therapeutic targets. Environmental factors, such as drugs, diet, and pollution, may also be the triggers of epigenetic changes. Therefore, this chapter will summarize the up-to-date progress on epigenetics regulation in lupus, in order to broaden our understanding of lupus and discuss the potential roles of epigenetic regulations for clinical applications.

Germinal Centre B Cell Functions and Lymphomagenesis: Circuits Involving MYC and MicroRNAs

BACKGROUND

The transcription factor MYC regulates several biological cellular processes, and its target gene network comprises approximately 15% of all human genes, including microRNAs (miRNAs), that also contribute to MYC regulatory activity. Although miRNAs are emerging as key regulators of immune functions, the specific roles of miRNAs in the regulation/dysregulation of germinal centre B-cells and B-cell lymphomas are still being uncovered. The regulatory network that integrates MYC, target genes and miRNAs is a field of intense study, highlighting potential pathways to be explored in the context of future clinical approaches.

METHODS

The scientific literature that is indexed in PUBMED was consulted for publications involving MYC and miRNAs with validated bioinformatics analyses or experimental protocols. Additionally, seminal studies on germinal centre B-cell functions and lymphomagenesis were reported.

CONCLUSIONS

This review summarizes the interactions between MYC and miRNAs through regulatory loops and circuits involving target genes in germinal centre B-cell lymphomas with MYC alterations. Moreover, we provide an overview of the understanding of the regulatory networks between MYC and miRNAs, highlighting the potential implication of this approach for the comprehension of germinal centre B-cell lymphoma pathogenesis. Therefore, circuits involving MYC, target genes and miRNAs provide novel insight into lymphomagenesis that could be useful for new improved therapeutic strategies.

The Pathogenic Role of Dysregulated Epigenetic Modifications in Autoimmune Diseases

Autoimmune diseases can be chronic with relapse of inflammatory symptoms, but it can be also acute and life-threatening if immune cells destroy life-supporting organs, such as lupus nephritis. The etiopathogenesis of autoimmune diseases has been revealed as that genetics and environmental factors-mediated dysregulated immune responses contribute to the initiation and development of autoimmune disorders. However, the current understanding of pathogenesis is limited and the underlying mechanism has not been well defined, which lows the development of novel biomarkers and new therapeutic strategies for autoimmune diseases. To improve this, broadening and deepening our understanding of pathogenesis is an unmet need. As genetic susceptibility cannot explain the low accordance rate of incidence in homozygous twins, epigenetic regulations might be an additional explanation. Therefore, this review will summarize current progress of studies on epigenetic dysregulations contributing to autoimmune diseases, including SLE, rheumatoid arthritis (RA), psoriasis, type 1 diabetes (T1D), and systemic sclerosis (SSc), hopefully providing opinions on orientation of future research, as well as discussing the clinical utilization of potential biomarkers and therapeutic strategies for these diseases.

MicroRNA-181a Inhibits Activated B-Cell-Like Diffuse Large B-Cell Lymphoma Progression by Repressing CARD11

We investigated the role of miR-181a in diffuse large B-cell lymphoma (DLBCL) and its potential target genes. miR-181a levels were lower in activated B-cell- (ABC-) like DLBCL cells than that in germinal center B-cell- (GCB-) like DLBCL cells. Overexpression of miR-181a in ABC-like DLBCL cell lines (OCI-LY10 and U2932) resulted in G0/G1 cell cycle arrest, increased apoptosis, and decreased invasiveness. miRNA target prediction programs (miRanda, TargetScan, and miRDB) identified caspase recruitment domain-containing protein 11 (CARD11) as a putative miR-181a target. CARD11 mRNA and protein levels were higher in the ABC-like DLBCL than that in GCB-like DLBCL. Moreover, CARD11 mRNA and protein levels were downregulated in the OCI-LY10 and U2932 cell lines overexpressing miR-181a. Dual luciferase reporter assays confirmed the miR-181a binding site in the CARD11 3'UTR region. OCI-LY10 and U2932 cells transfected with a CARD11 expression vector encoding miR-181a with a mutated binding site showed higher CARD11 protein levels, cell viability, G2/M phase cells, and invasiveness compared to those transfected with a wild-type CARD11 expression vector. Nude mice xenografted with OCI-LY10 cells with overexpressed wild-type miR-181a generated smaller tumors compared to those with overexpressed mutated binding site of CARD11 3'UTR and miR-181a. These results indicate that miR-181a inhibits ABC-like DLBCL by repressing CARD11.

Epigenetic Priming in Immunodeficiencies

Immunodeficiencies (IDs) are disorders of the immune system that increase susceptibility to infections and cancer, and are therefore associated with elevated morbidity and mortality. IDs can be primary (not caused by other condition or exposure) or secondary due to the exposure to different agents (infections, chemicals, aging, etc.). Most primary immunodeficiencies (PIDs) are of genetic origin, caused by mutations affecting genes with key roles in the development or function of the cells of the immune system. A large percentage of PIDs are associated with a defective development and/or function of lymphocytes and, especially, B cells, the ones in charge of generating the different types of antibodies. B-cell development is a tightly regulated process in which many different factors participate. Among the regulators of B-cell differentiation, a correct epigenetic control of cellular identity is essential for normal cell function. With the advent of next-generation sequencing (NGS) techniques, more and more alterations in different types of epigenetic regulators are being described at the root of PIDs, both in humans and in animal models. At the same time, it is becoming increasingly clear that epigenetic alterations triggered by the exposure to environmental agents have a key role in the development of secondary immunodeficiencies (SIDs). Due to their largely reversible nature, epigenetic modifications are quickly becoming key therapeutic targets in other diseases where their contribution has been known for more time, like cancer. Here, we establish a parallelism between IDs and the nowadays accepted role of epigenetics in cancer initiation and progression, and propose that epigenetics forms a "third axis" (together with genetics and external agents) to be considered in the etiology of IDs, and linking PIDs and SIDs at the molecular level. We therefore postulate that IDs arise due to a variable contribution of (i) genetic, (ii) environmental, and (iii) epigenetic causes, which in fact form a continuum landscape of all possible combinations of these factors. Additionally, this implies the possibility of a fully epigenetically triggered mechanism for some IDs. This concept would have important prophylactic and translational implications, and would also imply a more blurred frontier between primary and secondary immunodeficiencies.

MicroRNA profiles in B-cell non-Hodgkin lymphoma

B-cell non-Hodgkin's lymphomas are tumors of B-cells that arise following clonal expansion and consequent invasion of immune organs by B-cells blocked at a certain step of the differentiation process. Genetic abnormalities with altered gene expression are common in the transformed state of B-cells at any stage of B-cell development. These stages are regulated by a combination of transcription factors, epigenetic modifications, microRNAs, and extrinsic signals. MicroRNAs are a class of short non-coding single-stranded RNAs implicated in the regulation of mRNA function and translation. Each microRNA can regulate multiple transcripts; and a transcript is under potential control by multiple microRNAs. Their dysregulation can contribute to the pathogenesis of B-cell non-Hodgkin lymphomas, and they could be used as a potential target for diagnosis, evaluation of prognosis and therapy monitoring. The mechanisms of microRNA dysregulation range from dysregulation of the DNA sequences encoding the microRNAs to transcriptional regulation of microRNA loci. In this review, we summarized the microRNA profiles of the most common B-cell Non-Hodgkin Lymphomas for the pathogenesis, diagnosis and their potential therapeutic implications.

The role of microRNAs in newborn brain development and hypoxic ischaemic encephalopathy

Neonates can develop hypoxic-ischaemic encephalopathy (HIE) due to lack of blood supply or oxygen, resulting in a major cause of death and disability among term newborns. However, current definitive treatment of therapeutic hypothermia, will only benefit one out of nine babies. Furthermore, the mechanisms of HIE and therapeutic hypothermia are not fully understood. Recently, microRNAs (miRNAs) have become of interest to many researchers due to their important role in post-transcriptional control and deep evolutionary history. Despite this, role of miRNAs in newborns with HIE remains largely unknown due to limited research in this field. Therefore, this review aims to understand the role of miRNAs in normal brain development and HIE pathophysiology with reliance on extrapolated data from other diseases, ages and species due to current limited data. This will provide us with an overview of how miRNAs in normal brain development changes after HIE. Furthermore, it will indicate how miRNAs are affected specifically or globally by the various pathophysiological events. In addition, we discuss about how drugs and commercially available agents can specifically target certain miRNAs as a mechanism of action and potential safety issue with off-target effects. Improving our understanding of the role of miRNAs on the cellular response after HIE would enhance the success of effective diagnosis, prognosis, and treatment of newborns with HIE.

Role of humoral immunity against hepatitis B virus core antigen in the pathogenesis of acute liver failure

Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome leading to death or liver transplantation in 80% of cases. Due to the extremely rapid clinical course, the difficulties in obtaining liver specimens, and the lack of an animal model, the pathogenesis of ALF remains largely unknown. Here, we performed a comprehensive genetic and functional characterization of the virus and the host in liver tissue from HBV-associated ALF and compared the results with those of classic acute hepatitis B in chimpanzees. In contrast with acute hepatitis B, HBV strains detected in ALF livers displayed highly mutated HBV core antigen (HBcAg), associated with increased HBcAg expression ex vivo, which was independent of viral replication levels. Combined gene and miRNA expression profiling revealed a dominant B cell disease signature, with extensive intrahepatic production of IgM and IgG in germline configuration exclusively targeting HBcAg with subnanomolar affinities, and complement deposition. Thus, HBV ALF appears to be an anomalous T cell-independent, HBV core-driven B cell disease, which results from the rare and unfortunate encounter between a host with an unusual B cell response and an infecting virus with a highly mutated core antigen.

Activation-induced deaminase and its splice variants associate with trisomy 12 in chronic lymphocytic leukemia

Activation-induced cytidine deaminase (AID) is a mutator enzyme essential for somatic hypermutation (SHM) and class switch recombination (CSR) during effective adaptive immune responses. Its aberrant expression and activity have been detected in lymphomas, leukemias, and solid tumors. In chronic lymphocytic leukemia (CLL) increased expression of alternatively spliced AID variants has been documented. We used real-time RT-PCR to quantify the expression of AID and its alternatively spliced transcripts (AIDΔE4a, AIDΔE4, AIDivs3, and AIDΔE3E4) in 149 CLL patients and correlated this expression to prognostic markers including recurrent chromosomal aberrations, the presence of complex karyotype, mutation status of the immunoglobulin heavy chain variable gene, and recurrent mutations. We report a previously unappreciated association between higher AID transcript levels and trisomy of chromosome 12. Functional analysis of AID splice variants revealed loss of their activity with respect to SHM, CSR, and induction of double-strand DNA breaks. In silico modeling provided insight into the molecular interactions and structural dynamics of wild-type AID and a shortened AID variant closely resembling AIDΔE4, confirming its loss-of-function phenotype.

MicroRNAs as Biomarkers of B-cell Lymphoma

B-cell lymphomas represent a diverse group of neoplasms classified primarily by histopatholgy and are often challenging to accurately diagnose. Despite having been recognized less than 20 years ago, microRNAs (miRNAs) have emerged as one of the most promising class of cancer molecular biomarkers and are particularly attractive as they can be readily detected in formalin-fixed paraffin-embedded biopsy material and biological fluids such as blood. Many of the identified B-cell lymphoma miRNA biomarkers also play crucial regulatory roles in normal B-cell development. Below we consider the identity, function, and biomarker potential of miRNAs in B-cell lymphoma and most importantly the barriers that remain to be overcome if they are really to become part of routine clinical practice.

MicroRNAs and immunity in periodontal health and disease

MicroRNAs (miRNAs) are critical regulators of the host immune and inflammatory response against bacterial pathogens. In the present review, we discuss target genes, target gene functions, the potential regulatory role of miRNAs in periodontal tissues, and the potential role of miRNAs as biomarkers and therapeutics. In periodontal disease, miRNAs exert control over all aspects of innate and adaptive immunity, including the functions of neutrophils, macrophages, dendritic cells and T and B cells. Previous human studies have highlighted some key miRNAs that are dysregulated in periodontitis patients. In the present study, we mapped the major miRNAs that were altered in our reproducible periodontitis mouse model relative to control animals. The miRNAs that were upregulated as a result of periodontal disease in both human and mouse studies included miR-15a, miR-29b, miR-125a, miR-146a, miR-148/148a and miR-223, whereas miR-92 was downregulated. The association of individual miRNAs with unique aspects of periodontal disease and their stability in gingival crevicular fluid underscores their potential as markers for periodontal disease progression or healthy restitution. Moreover, miRNA therapeutics hold great promise for the future of periodontal therapy because of their ability to modulate the immune response to infection when applied in conjunction with synthetic antagomirs and/or relatively straightforward delivery strategies.

miR-29b directly targets activation-induced cytidine deaminase in human B cells and can limit its inappropriate expression in naïve B cells

Class-switch recombination (CSR) is an essential B cell process that alters the isotype of antibody produced by the B cell, tailoring the immune response to the nature of the invading pathogen. CSR requires the activity of the mutagenic enzyme AID (encoded by AICDA) to generate chromosomal lesions within the immunoglobulin genes that initiate the class switching recombination event. These AID-mediated mutations also participate in somatic-hypermutation of the immunoglobulin variable region, driving affinity maturation. As such, AID poses a significant oncogenic threat if it functions outside of the immunoglobulin locus. We found that expression of the microRNA, miR-29b, was repressed in B cells isolated from tonsil tissue, relative to circulating naïve B cells. Further investigation revealed that miR-29b was able to directly initiate the degradation of AID mRNA. Enforced overexpression of miR-29b in human B cells precipitated a reduction in overall AID protein and a corresponding diminution in CSR to IgE. Given miR-29b's ability to potently target AID, a mutagenic molecule that can initiate chromosomal translocations and "off-target" mutations, we propose that miR-29b acts to silence premature AID expression in naïve B cells, thus reducing the likelihood of inappropriate and potentially dangerous deamination activity.

Diversity in the Cow Ultralong CDR H3 Antibody Repertoire

Typical antibodies found in humans and mice usually have short CDR H3s and generally flat binding surfaces. However, cows possess a subset of antibodies with ultralong CDR H3s that can range up to 70 amino acids and form a unique “stalk and knob” structure, with the knob protruding far out of the antibody surface, where it has the potential to bind antigens with concave epitopes. Activation-induced cytidine deaminase (AID) has a proven role in diversifying antibody repertoires in humoral immunity, and it has been found to induce somatic hypermutation in bovine immunoglobulin genes both before and after contact with antigen. Due to limited use of variable and diversity genes in the V(D)J recombination events that produce ultralong CDR H3 antibodies in cows, the diversity in the bovine ultralong antibody repertoire has been proposed to rely on AID-induced mutations targeted to the IGHD8-2 gene that encodes the entire knob region. In this review, we discuss the genetics, structures, and diversity of bovine ultralong antibodies, as well as the role of AID in creating a diverse antibody repertoire.

miR-181b inhibits chemoresistance in cisplatin-resistant H446 small cell lung cancer cells by targeting Bcl-2

INTRODUCTION

MicroRNAs (miRNAs) are a group of small non-coding RNAs that affect multiple aspects of tumor biology including chemo resistance. miR-181b has been reported to modulate multidrug resistance in non-small cell lung cancer cells. This study was undertaken to determine the role of miR-181b in chemo resistance of small cell lung cancer cells.

MATERIAL AND METHODS

This study was undertaken to determine the role of miR-181b in chemoresistance of small cell lung cancer cells with use of qRt-PCR, WB, bioinformatics analysis, and double luciferase reporter system.

RESULTS

Our data showed that miR-181b was significantly downregulated in cisplatin-resistant H446 small cell lung cancer cells, compared to parental cells, compared to parental cells. Ectopic expression of miR-181b inhibited cell proliferation and invasion in cisplatin-resistant H446 cells (p = 0.023). Moreover, overexpression of miR-181b increased the susceptibility of cisplatin-resistant H446 cells to cisplatin. Mechanistic investigations demonstrated that miR-181b inhibited B-cell lymphoma-2 (Bcl-2) expression by binding to the 3'-untranslated region. Overexpression of Bcl-2 reversed miR-181b-mediated chemo sensitization, which is accompanied by a reduced apoptotic response.

CONCLUSIONS

Taken together, this work demonstrated that miR-181b might have the ability to overcome chemo resistance of small cell lung cancer cells, and restoration of this miRNA may represent a potential therapeutic strategy for improving chemo sensitivity in small cell lung cancer.