Histone deacetylase inhibitors suppress CXCR4-mediated dendritic cell migration by regulation of maturation process

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.

The Emerging Roles of Heterochromatin in Cell Migration

Cell migration is a key process in health and disease. In the last decade an increasing attention is given to chromatin organization in migrating cells. In various types of cells induction of migration leads to a global increase in heterochromatin levels. Heterochromatin is required for optimal cell migration capabilities, since various interventions with heterochromatin formation impeded the migration rate of numerous cell types. Heterochromatin supports the migration process by affecting both the mechanical properties of the nucleus as well as the genetic processes taking place within it. Increased heterochromatin levels elevate nuclear rigidity in a manner that allows faster cell migration in 3D environments. Condensed chromatin and a more rigid nucleus may increase nuclear durability to shear stress and prevent DNA damage during the migration process. In addition, heterochromatin reorganization in migrating cells is important for induction of migration-specific transcriptional plan together with inhibition of many other unnecessary transcriptional changes. Thus, chromatin organization appears to have a key role in the cellular migration process.

Neutralizing negative epigenetic regulation by HDAC5 enhances human haematopoietic stem cell homing and engraftment

Enhancement of hematopoietic stem cell (HSC) homing and engraftment is clinically critical, especially for cord blood (CB) hematopoietic cell transplantation. Here we report that specific HDAC5 inhibition highly upregulates CXCR4 surface expression in human CB HSCs and progenitor cells (HPCs). This results in enhanced SDF-1/CXCR4-mediated chemotaxis and increased homing to the bone marrow environment, with elevated SCID-repopulating cell (SRC) frequency and enhanced long-term and secondary engraftment in NSG mice. HDAC5 inhibition increases acetylated p65 levels in the nucleus, which is important for CXCR4 transcription. Inhibition of nuclear factor-κB (NF-κB) signaling suppresses HDAC5-mediated CXCR4 upregulation, enhanced HSC homing, and engraftment. Furthermore, activation of the NF-κB signaling pathway via TNFα also results in significantly increased CXCR4 surface expression, enhanced HSC homing, and engraftment. These results demonstrate a previously unknown negative epigenetic regulation of HSC homing and engraftment by HDAC5, and allow for a new and simple translational strategy to enhance HSC transplantation.

Enhancement of haematopoietic stem cell (HSC) homing and engraftment is critical for haematopoietic cell transplantation. Here, the authors find that HDAC5 inhibition enhances HSC homing and engraftment by increasing p65 acetylation and enhancing NF-kB mediated CXCR4 transcription.

Histone deacetylase inhibitors suppress immature dendritic cell's migration by regulating CC chemokine receptor 1 expression

The modulation of immature dendritic cells (iDCs), which involves processes such as phagocytosis, migration, and maturation, is considered a beneficial research theme. Once activated by an antigen, iDCs turn to mature DCs (mDCs) and migrate towards secondary lymphoid organs, and initiate the progress of cellular immunity. Histone deacetylase inhibitors (HDACis) are also thought to be a major modulator of cellular immunity. Herein, we demonstrate that HDACis (trichostatin-A (TSA), sodium butylate (SB), scriptaid (ST)) play a central regulatory role in the migratory activity of iDCs. In our results, TSA, SB and ST showed the potent inhibitory effect on the migration of iDCs stimulated by MIP-1α. The inhibitory activities of HDACis were found to be caused by reduction of CCR1 expression on the cell surface, and by the inhibition of phosphorylation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases 1 and 2 (ERK 1/2), and c-Jun N-terminal kinase (JNK).

Histone Modifications and Asthma. The Interface of the Epigenetic and Genetic Landscapes

Complex lung diseases, such as asthma, are influenced by both genetic predisposition and environmental stimuli. The epigenetic landscape of such diseases is attracting increasing interest and research. Epigenetics broadly covers the transient and the inheritable changes to gene expression that are not directly due to changes in nucleotide sequences. Epigenetic mechanisms could have significant impact on asthma-related allergic, immune, and regulatory pathways, as well as on the generation of biomarkers and the heritable transmission of asthma phenotypes. Recent technological advances have allowed mapping of the epigenome and analysis of genome-wide epigenetic contributors to disease. As a result, ground-breaking observations regarding histone post-translational modifications in a number of immunological diseases have emerged. In this review, we look beyond the biological information coded by DNA and review the epigenetic modifications made to histones, with evidence suggesting a role for their modification in asthma.

Eupolyphaga sinensis walker displays inhibition on hepatocellular carcinoma through regulating cell growth and metastasis signaling

Tumor growth and metastasis are responsible for most cancer patients' deaths. Here, we report that eupolyphaga sinensis walker has an essential role in resisting hepatocellular carcinoma growth and metastasis. Compared with proliferation, colony formation, transwell assay and transplantable tumor in nude mouse in vitro and vivo, eupolyphaga sinensis walker extract (ESWE) showed good inhibition on the SMMC-7721 cell growth and metastasis. Using genome-wide microarray analysis, we found the down-regulated growth and metastasis factors, and selected down-regulated genes were confirmed by real-time PCR. Knockdown of a checkpoint PKCβ by siRNA significantly attenuated tumor inhibition and metastasis effects of ESWE. Moreover, our results indicate ESWE inhibits HCC growth by not only downregulating the signaling of PKCβ, Akt, m-TOR, Erk1/2, MEK-2, Raf and JNK-1, but also increasing cyclin D1 protein levels and decreasing amount of cyclin E, cyclin B1 and cdc2 of the cycle proteins. At the same time, ESWE reduced MMP2, MMP9 and CXCR4, PLG, NFκB and P53 activities. Overall, our studies demonstrate that ESWE is a key factor in growth and metastasis signaling inhibitor targeting the PKC, AKT, MAPK signaling and related metastasis signaling, having potential in cancer therapy.