Increased PARylation impacts the DNA methylation process in type 2 diabetes mellitus

Epigenetic modifications, such as DNA methylation, can influence the genetic susceptibility to type 2 diabetes mellitus (T2DM) and the progression of the disease. Our previous studies demonstrated that the regulation of the DNA methylation pattern involves the poly(ADP-ribosyl)ation (PARylation) process, a post-translational modification of proteins catalysed by the poly(ADP-ribose) polymerase (PARP) enzymes. Experimental data showed that the hyperactivation of PARylation is associated with impaired glucose metabolism and the development of T2DM. Aims of this case-control study were to investigate the association between PARylation and global and site-specific DNA methylation in T2DM and to evaluate metabolic correlates

The open abdomen in trauma and non-trauma patients : WSES guidelines

Damage control resuscitation may lead to postoperative intra-abdominal hypertension or abdominal compartment syndrome. These conditions may result in a vicious, self-perpetuating cycle leading to severe physiologic derangements and multiorgan failure unless interrupted by abdominal (surgical or other) decompression. Further, in some clinical situations, the abdomen cannot be closed due to the visceral edema, the inability to control the compelling source of infection or the necessity to re-explore (as a "planned second-look" laparotomy) or complete previously initiated damage control procedures or in cases of abdominal wall disruption. The open abdomen in trauma and non-trauma patients has been proposed to be effective in preventing or treating deranged physiology in patients with severe injuries or critical illness when no other perceived options exist. Its use, however, remains controversial as it is resource consuming and represents a non-anatomic situation with the potential for severe adverse effects. Its use, therefore, should only be considered in patients who would most benefit from it. Abdominal fascia-to-fascia closure should be done as soon as the patient can physiologically tolerate it. All precautions to minimize complications should be implemented.Peer reviewe

The role of Yin and Yang 1 (YY1) transcription factor in acute myeloid leukemia (AML)

“The role of Yin and Yang 1 (YY1) transcription factor in Acute Myeloid Leukemia (AML)” Introduction: Acute Myeloid Leukemia is an heterogeneous disease with different molecular signatures, therapeutic responses, and survival rates. Recent studies suggest that the transcription factor YY1 is overexpressed in AML patients and it may have a role in the onset of AML differentiation block. Our aim was to investigate the role and the effect of YY1 downregulation in granulocytic differentiation. Methods: We used molecular and cellular biology methods such as plasmid constructions and lentiviral infection, qRT-PCR, Western Blot, Immonophenotypes, Morphological analysis and Apoptotic assays. Results: Our results confirm a higher level of YY1 gene expression in AML patients compared to CD34+ hematopoietic progenitors and CD34- mature cells. When YY1 is downregulated, by short hairpin interference in HL60 myeloid cell line, we observed a significant increase in the expression of factors relevant to myeloid differentiation and in particular to granulocytic maturation, such as GMCSFr, GCSFr, CEBPε and CEBPδ and a significant decrease of the MPO gene expression. We also measured an increase in the staining of the CD11b surface antigene. Importantly, YY1 downregulation reinforced the prodifferentiative effects of all trans retinoic acid (RA) treatment compared to RA treated HL60 cells expressing YY1, including an increase in CEBPα gene expression and morphological changes compatible with granulocytic maturation. YY1 knockdown determined a significant increase of RARα expression that is crucial to mediate the intracellular effects of RA. In addition, YY1 knockdown also promoted a terminal apoptosis in RA HL60 treated cells, as shown by the activation of caspasis, increased expression of BAX gene and increased Annexin V and Propidium Iodide stainings. Conclusions: We identified YY1 as an important player in the onset of the differentiation block in AML HL60 cell line. Indeed, in these cells YY1 downregulation remove the differentiation block and restore a myeloid differentiation gene expression program, mainly toward granulocytic lineage. Moreover, YY1 downregulation reinforces the therapeutic effect of RA treatment

Modifications of H3 K4methylation levels are associated with DNA hypermethylation in acute myeloid leukemia

The 'instructive model' of aberrant DNA methylation in human tumors is based on the observation that CpG islands prone to hypermethylation in cancers are embedded in chromatin enriched in H3K27me3 in human embryonic stem cells (hESC). Recent studies also link methylation of CpG islands to the methylation status of H3K4, where H3K4me3 is inversely correlated with DNA methylation. To provide insight into these conflicting findings, we generated DNA methylation profiles for acute myeloid leukemia samples from patients and leukemic cell lines and integrated them with publicly available ChIp-seq data, containing H3K4me3 and H3K27me3 CpG island occupation in hESC, or hematopoietic stem or progenitor cells (hHSC/MPP). Hypermethylated CpG islands in AML samples displayed H3K27me3 enrichments in hESC and hHSC/MPP; however, ChIp analysis of specific hypermethylated CpG islands revealed a significant reduction in H3K4me3 signal with a concomitant increase in H3K4me0 levels as opposed to a nonsignificant increase in H3K27me3 marks. The integration of AML DNA methylation profiles with the ChIp-seq data in hESC and hHSC/MPP also led to the identification of Iroquois homeobox 2 (IRX2) as a previously unknown factor promoting differentiation of leukemic cells. Our results indicate that in contrast to the 'instructive model', H3K4me3 levels are strongly associated with DNA methylation patterns in AML and have a role in the regulation of critical genes, such as the putative tumor suppressor IRX2

Inflammation and endocannabinoid system: the role of epigenetic modifications in BV2 cells treated with amyloid beta peptide

Numerous studies indicate that inflammatory processes and disturbed neuron-microglia interactions may mediate the pathogenesis of Alzheimer disease (AD), which is characterized by progressive memory impairment and cognitive deficits. The disease is associated with the presence of extracellular senile plaques mainly composed of amyloid-beta peptide (Abeta) and intraneuronal neurofibrillary tangles containing hyperphosphorylated tau protein (1). To date, the pathophysiology of AD is not completely unveiled, but increasing evidences suggest that epigenetic mechanisms may play a role in tracking the course and development of AD. Recent studies have indicated that Endocannabinoid (eCB) levels and metabolic enzymes change during the progression of AD and the inhibition of the major N-Arachidonoylethanolamine (AEA)-hydrolyzing enzyme, fatty acid amide hydrolase (FAAH), has beneficial effects in AD mice (2, 3). Our study is aimed at revealing the immune-modulatory effects induced by targeting FAAH with URB597, a well known FAAH inhibitor. This compound, an aryl ester of carbamic acid, inhibits the degradative metabolism of AEA as well as other eCBs. We have investigated whether epigenetic actors as the histone post-translational modifications, may affect inflammatory response in BV2 murine microglia cells challenged with Abeta in presence or absence of URB597. In order to evaluate the possible URB597 cytotoxicity on BV2 cells and to define the optimal concentration for the purpose analyzes, cell viability experiments by MTT assay were performed. The results show that URB597, used at concentrations up to 10 uM, does not exert negative effects on cell viability, even when treatment is continued for 72 h, indicating that the inhibitor does not interfere with the survival capability of the cells. According to the literature data, we used a concentration of URB597 of 5 uM. Therefore, BV2 cells were treated with 30 uM Abeta25-35 in presence or absence of 5 uM URB597. To evaluate the protein level of pan-acetylated histone H3 and methylated histone H3 on lysine 27 (H3K27me3) in our experimental model, we performed Western blot analyses. We observed an increase of pan-acetylated histone H3 protein level in all treated samples with respect to control. Conversely a diminution in of H3K27me3 level were found in URB597 treated sample compared to those treated only with Abeta and to control. To determine the level of inflammatory state in our BV2 cellular models, we analyzed, by qRT-PCR, the expression of pro-inflammatory interleukins as IL-1beta, TNFalfa and IL-6 as well as anti-inflammatory interleukins as TGFbeta, L-10, IL-4. The results demonstrate that pro-inflammatory interleukins expression as IL-1beta, TNFalfa increases within 1-3 hours (short time) in BV2 cells treated with Abeta compared to untreated control, whereas IL-6 expression increases after 6 hours of treatment. URB597 did not affect the expression of the same pro-inflammatory genes, whereas FAAH inhibitor is able to modulate the TGFbeta, IL-10 interleukins gene expression within 6-24 h. Chromatin immune-precipitation analyses (ChIp) using anti-H3 pan-acetyl and anti-H3K27me3 antibodies were performed to study promoter chromatin modifications that may accompany changes of pro and anti inflammatory ILs expression. Although not conclusive, our data show that TGFbeta and IL-10 chromatin promoters acquire a chromatin enriched of H3 pan acetyl modification and reduce levels of H3K27me3 gene expression when contemporary treated with Abeta and URB597. The obtained data suggest that an increase of AEA, due to FAAH inhibition, may contribute to decrease the inflammation cellular response modulating pro-inflammatory interleukins at chromatin level. References: 1) Selkoe DJ (2001) Alzheimer's disease: genes, proteins, and therapy. Physiol Rev 81: 741-766. 2) Bisogno T., Di Marzo V. (2008) The role of the endocannabinoid system in Alzheimer's disease: facts and hypotheses. Curr Pharm Des. 2008;14(23):2299-3305 3)Basavarajappa B, Shivakumar M, Joshi V, Subbanna S. (2017) Endocannabinoid system in neurodegenerative disorders. Neurochem. 142(5):624-648

YY1 Knockdown Relieves the Differentiation Block and Restores Apoptosis in AML Cells

acute myeloid leukemia (AML) is characterized by the expansion of clonally derived hematopoietic precursors undergoing a partial or complete maturation block. de novo AML is characterized by recurrent cytogenetic alterations such as chromosomal translocations. however, in the recent past, it was shown that several somatic mutations and epigenetic alterations also contribute to AML onset and progression. epigenetic mechanisms regulate the equilibrium between self-renewal and differentiation of hematopoietic stem cells and precursors. In this context, Polycomb-group (PcG) proteins regulate the expression of genes involved in cell-cycle regulation and differentiation, and aberrant expression and/or mutations of PcG genes have been shown to occur in hematopoietic neoplasms.In this study we analyzed the expression of Yin and Yang 1 protein (YY1), a member of the noncanonical PcG complexes, in AML patient samples and AML cell lines and the effect of YY1 downregulation on the AML differentiation block. our results show that YY1 is significantly overexpressed in AML patient samples and AML cell lines and that YY1 knockdown relieves the differentiation block. YY1 downregulation in two AML cell lines (HL-60 and OCI-AML3) and one AML patient sample restored the expression of members of the CEBP protein family, increased the expression of extrinsic growth factors/receptors and surface antigenic markers, induced morphological cell characteristics typical of myeloid differentiation, and sensitized cells to retinoic acid treatment and to apoptosis. overall, our data show that YY1 is not a secondary regulator of myeloid differentiation but that, if overexpressed, it can play a predominant role in myeloid differentiation block