C/EBPε ΔRS derived from a neutrophil-specific granule deficiency patient interacts with HDAC1 and its dysfunction is restored by trichostatin A

CCAAT/Enhancer-Binding Proteins in Fibrosis: Complex Roles Beyond Conventional Understanding

CCAAT/enhancer-binding proteins (C/EBPs) are a family of at least six identified transcription factors that contain a highly conserved basic leucine zipper domain and interact selectively with duplex DNA to regulate target gene expression. C/EBPs play important roles in various physiological processes, and their abnormal function can lead to various diseases. Recently, accumulating evidence has demonstrated that aberrant C/EBP expression or activity is closely associated with the onset and progression of fibrosis in several organs and tissues. During fibrosis, various C/EBPs can exert distinct functions in the same organ, while the same C/EBP can exert distinct functions in different organs. Modulating C/EBP expression or activity could regulate various molecular processes to alleviate fibrosis in multiple organs; therefore, novel C/EBPs-based therapeutic methods for treating fibrosis have attracted considerable attention. In this review, we will explore the features of C/EBPs and their critical functions in fibrosis in order to highlight new avenues for the development of novel therapies targeting C/EBPs.

A Novel CEBPE Variant Causes Severe Infections and Profound Neutropenia

PURPOSE

Specific granule deficiency (SGD) is a rare inborn error of immunity resulting from loss-of-function variants in CEBPE gene (encoding for transcription factor C/EBPε). Although this genetic etiology has been known for over two decades, only a few patients with CEBPE variant-proven SGD (type I) have been reported. Herein, we describe two siblings with a novel homozygous CEBPE deletion who were noted to have profound neutropenia on initial evaluation. We aimed to evaluate the immunohematological consequences of this novel variant, including profound neutropenia.

METHODS

Light scatter characteristics of granulocytes were examined on various automated hematology analyzers. Phagocyte immunophenotype, reactive oxygen species generation, and Toll-like receptor (TLR) signaling were assessed using flow cytometry. Relative expression of genes encoding various granule proteins was studied using RT-PCR. Western blot analysis and luciferase reporter assay were performed to explore variant C/EBPε expression and function.

RESULTS

Severe infections occurred in both siblings. Analysis of granulocyte light scatter plots revealed automated hematology analyzers can provide anomalously low neutrophil counts due to abnormal neutrophil morphology. Neutrophils displayed absence/marked reduction of CD15/CD16 expression and overexpression (in a subset) of CD14/CD64. Three distinct populations of phagocytes with different oxidase activities were observed. Impaired shedding of CD62-ligand was noted on stimulation with TLR-4, TLR-2/6, and TLR-7/8 agonists. We demonstrated the variant C/EBPε to be functionally deficient.

CONCLUSION

Homozygous c.655_665del variant in CEBPE causes SGD. Anomalous automated neutrophil counts may be reported in patients with SGD type I. Aberrant TLR signaling might be an additional pathogenetic mechanism underlying immunodeficiency in SGD type I.

Neutrophils in cancer carcinogenesis and metastasis

In recent years, neutrophils have attracted increasing attention because of their cancer-promoting effects. An elevated neutrophil-to-lymphocyte ratio is considered a prognostic indicator for patients with cancer. Neutrophils are no longer regarded as innate immune cells with a single function, let alone bystanders in the pathological process of cancer. Their diversity and plasticity are being increasingly recognized. This review summarizes previous studies assessing the roles and mechanisms of neutrophils in cancer initiation, progression, metastasis and relapse. Although the findings are controversial, the fact that neutrophils play a dual role in promoting and suppressing cancer is undeniable. The plasticity of neutrophils allows them to adapt to different cancer microenvironments and exert different effects on cancer. Given the findings from our own research, we propose a reasonable hypothesis that neutrophils may be reprogrammed into a cancer-promoting state in the cancer microenvironment. This new perspective indicates that neutrophil reprogramming in the course of cancer treatment is a problem worthy of attention. Preventing or reversing the reprogramming of neutrophils may be a potential strategy for adjuvant cancer therapy.

Preclinical and clinical progress for HDAC as a putative target for epigenetic remodeling and functionality of immune cells

Genetic changes are difficult to reverse; thus, epigenetic aberrations, including changes in DNA methylation, histone modifications, and noncoding RNAs, with potential reversibility, have attracted attention as pharmaceutical targets. The current paradigm is that histone deacetylases (HDACs) regulate gene expression via deacetylation of histone and nonhistone proteins or by forming corepressor complexes with transcription factors. The emergence of epigenetic tools related to HDACs can be used as diagnostic and therapeutic markers. HDAC inhibitors that block specific or a series of HDACs have proven to be a powerful therapeutic treatment for immune-related diseases. Here, we summarize the various roles of HDACs and HDAC inhibitors in the development and function of innate and adaptive immune cells and their implications for various diseases and therapies.

Disease Presentation, Treatment Options, and Outcomes for Myeloid Immunodeficiencies

PURPOSE OF REVIEW

Up-to-date review on various types of immunodeficiencies with a significant myeloid component including some more recently described congenital disorders.

RECENT FINDINGS

While a number of disorders have been described in the past, genetic sequencing has led to the identification of the specific disorders and clarified their pathophysiology. Advances in genetic therapies including genetic editing should provide future treatments beyond hematopoietic stem cell transplant for patients with these rare disorders. Neutrophils (or granulocytes) are a major contributor to infection surveillance and clearance, and defective neutrophils characteristically lead to pyogenic infections. Deficiency in numbers, either iatrogenic or congenital; functional defects; and/or inability to target to the sites of infection can all lead to serious morbidity and mortality; however, myeloid-based immunodeficiencies are not all the same. Having absent neutrophils, that is, neutropenia, has implications different to those of having dysfunctional neutrophils as will become evident as the various disorders are reviewed.

Autophagic Vacuole Secretion Triggered by Chidamide Participates in TRAIL Apoptosis Effect in Breast Cancer Cells

BACKGROUND

Breast cancer is one of the most prevalent diseases threatening women's health today. Indepth research on breast cancer (BC) pathogenesis and prevention and treatment methods are gradually receiving attention. Chidamide is a novel histone deacetylase inhibitor (HDACi) that depresses the function of histone deacetylase, consequently affecting the growth of BC cells through epigenetic modification. However, preclinical and clinical studies show that chidamide is ineffective in long-term treatment. We demonstrated in previous experiments that TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis in BC cells and is significantly less non-toxic to normal cells than chidamide. Therefore, in this study, we treated BC cells with chidamide and TRAIL to explore a novel option to reduce the clinical toxicity through augmenting the sensitivity for BC cells.

METHODS AND RESULTS

Results from the MTT and cell viability assays indicated that the combination of chidamide and TRAIL in MCF-7 and MDA-MB-231 cells induced BC cell death, while maintaining a reduced concentration of chidamide. Autophagy assay and annexin V analysis showed that the autophagosome microtubuleassociated protein1light chain3-II (LC3-II) was abnormally increased and much more early and late phase of apoptotic cells appeared during chidamide and TRAIL induction. Anti-tumor assays in a BC tumor xenograft model displayed that the mixture of chidamide and TRAIL exhibited stronger effects on inhibiting tumor growth. The data from real-time PCR and western blotting showed that the cytotoxic effect correlated with the expressions of related apoptosis and autophagy factors.

CONCLUSION

Our data are the first to demonstrate the synergistic effects of chidamide and TRAIL in BC cells, specifically, the pharmacological effects on cell death induction. These results lay a solid experimental and theoretical basis to solve the clinical resistance of chidamide.