Effect of polystyrene nanoplastics exposure on gene expression and pathogenesis of zoonotic pathogen, Edwardsiella piscicida.

A surge in the number of anthropogenic pollutants has been caused by increasing industrial activities. Nanoplastics are spotlighted as a new aquatic pollutant that are a threat to microbes and larger organisms. Our previous study showed that the subinhibitory concentrations of aquatic pollutants such as phenol and formalin act as signaling molecules and modulate global gene expression and metabolism. In this study, we aimed to investigate the impact of a new type of anthropogenic contaminant, polystyrene (PS) nanoplastics, on the expression of key virulence factors in zoonotic pathogen Edwardsiella piscicida and the assessment of potential changes in the susceptibility of zebrafish as a model host. The TEM data indicated a noticeable change in the cell membrane indicating that PS particles were possibly entering the bacterial cells. Transcriptome analyses performed to identify the differentially expressed genes upon PS exposure revealed that the genes involved in major virulence factor type VI secretion system (T6SS) were down-regulated. However, the expression of T6SS-related genes was recovered from the PS adapted E. piscicida when nanoplastics are free. This demonstrated the hypervirulence of pathogen in infection assays with both cell lines and in vivo zebrafish model. Therefore, this study provides experimental evidence elucidating the direct regulatory impact of nanoplastics influx into aquatic ecosystems on fish pathogenic bacteria, notably influencing the expression of virulence factors.

DRG2 in macrophages is crucial for initial inflammatory response and protection against Listeria monocytogenes infection.

Innate immune response is critical for the control of Listeria monocytogenes infection. Here, we identified developmentally regulated GTP-binding protein 2 (DRG2) in macrophages as a major regulator of the innate immune response against L. monocytogenes infection. Both whole-body DRG2 knockout (KO) mice and macrophage-specific DRG2 KO mice had low levels of IL-6 during early infection and increased susceptibility to L. monocytogenes infection. Following an initial impaired inflammatory response of macrophages upon i.p. L. monocytogenes infection, DRG2-/- mice showed delayed recruitment of neutrophils and monocytes into the peritoneal cavity, which led to elevated bacterial burden, inflammatory cytokine production at a late infection time point, and liver micro-abscesses. DRG2 deficiency decreased the transcriptional activity of NF-κB and impaired the inflammatory response of both bone marrow-derived and peritoneal macrophages upon L. monocytogenes stimulation. Our findings reveal that DRG2 in macrophages is critical for the initial inflammatory response and protection against L. monocytogenes infection.

Interface polarization in heterovalent core-shell nanocrystals.

The potential profile and the energy level offset of core-shell heterostructured nanocrystals (h-NCs) determine the photophysical properties and the charge transport characteristics of h-NC solids. However, limited material choices for heavy metal-free III-V-II-VI h-NCs pose challenges in comprehensive control of the potential profile. Herein, we present an approach to such a control by steering dipole densities at the interface of III-V-II-VI h-NCs. The controllable heterovalency at the interface is responsible for interfacial dipole densities that result in the vacuum-level shift, providing an additional knob for the control of optical and electrical characteristics of h-NCs. The synthesis of h-NCs with atomic precision allows us to correlate interfacial dipole moments with the NCs' photochemical stability and optoelectronic performance.

Naturally occurring substitution in one amino acid in VHSV phosphoprotein enhances viral virulence in flounder.

Viral hemorrhagic septicemia virus (VHSV) is a rhabdovirus that causes high mortality in cultured flounder. Naturally occurring VHSV strains vary greatly in virulence. Until now, little has been known about genetic alterations that affect the virulence of VHSV in flounder. We recently reported the full-genome sequences of 18 VHSV strains. In this study, we determined the virulence of these 18 VHSV strains in flounder and then the assessed relationships between differences in the amino acid sequences of the 18 VHSV strains and their virulence to flounder. We identified one amino acid substitution in the phosphoprotein (P) (Pro55-to-Leu substitution in the P protein; PP55L) that is specific to highly virulent strains. This PP55L substitution was maintained stably after 30 cell passages. To investigate the effects of the PP55L substitution on VHSV virulence in flounder, we generated a recombinant VHSV carrying PP55L (rVHSV-P) from rVHSV carrying P55 in the P protein (rVHSV-wild). The rVHSV-P produced high level of viral RNA in cells and showed increased growth in cultured cells and virulence in flounder compared to the rVHSV-wild. In addition, rVHSV-P significantly inhibited the induction of the IFN1 gene in both cells and fish at 6 h post-infection. An RNA-seq analysis confirmed that rVHSV-P infection blocked the induction of several IFN-related genes in virus-infected cells at 6 h post-infection compared to rVHSV-wild. Ectopic expression of PP55L protein resulted in a decrease in IFN induction and an increase in viral RNA synthesis in rVHSV-wild-infected cells. Taken together, our results are the first to identify that the P55L substitution in the P protein enhances VHSV virulence in flounder. The data from this study add to the knowledge of VHSV virulence in flounder and could benefit VHSV surveillance efforts and the generation of a VHSV vaccine.

Simple surgical punctal occlusion with high frequency radiowave electrosurgery.

BACKGROUND: To introduce and evaluate the efficacy of a simple punctal occlusion technique for dry eye patients. METHODS: Medical records of 79 eyes from 40 patients refractory to common dry eye conservative treatment who underwent multiple high-frequency radio-wave electro-punctal occlusion were retrospectively reviewed. Pre- and post-procedural ocular surface indices (Schirmer test, tear break-up time (TBUT), and corneal staining grade (Oxford scheme)) and subjective symptom scores (including frequency of artificial tear use, interval between procedures, and total repeat time) were analyzed. RESULTS: Average Schirmer test result was significantly (P < 0.05) improved from 4.10 ± 1.39 mm to 8.14 ± 3.13 mm at 6 weeks after the procedure (n = 79). A total of 32 eyes from 16 patients underwent repeated procedure with a mean interval of 8.00 ± 4.86 months, while 24 patients had a single procedure. Twenty-five of 30 patients showed improvement for subjective symptom scores. No complications related to the procedure were observed. CONCLUSIONS: A simple, less-invasive punctal occlusion technique using a fine-needle tip with high-frequency radio-wave could significantly relieve subjective symptoms and improve ocular surface indices of patients with aqueous deficient dry eye without causing a major complication. This procedure may play a considerable role in treating dry eye refractory to common practices.

Sirtuin1-Mediated Deacetylation of Hypothalamic TTF-1 Contributes to the Energy Deficiency Response.

TTF-1 stimulates appetite by regulating the expression of agouti-related peptide (AgRP) and proopiomelanocortin (POMC) genes in the hypothalamus of starving animals. However, the mechanism underlying TTF-1's response to decreased energy levels remains elusive. Here, we provide evidence that the NAD+-dependent deacetylase, sirtuin1 (Sirt1), activates TTF-1 in response to energy deficiency. Energy deficiency leads to a twofold increase in the expression of both Sirt1 and TTF-1, leading to the deacetylation of TTF-1 through the interaction between the two proteins. The activation of Sirt1, induced by energy deficiency or resveratrol treatment, leads to a significant increase in the deacetylation of TTF-1 and promotes its nuclear translocation. Conversely, the inhibition of Sirt1 prevents these Sirt1 effects. Notably, a point mutation in a lysine residue of TTF-1 significantly disrupts its deacetylation and thus nearly completely hinders its ability to regulate AgRP and POMC gene expression. These findings highlight the importance of energy-deficiency-induced deacetylation of TTF-1 in the control of AgRP and POMC gene expression.

FOXO1 Is a Key Mediator of Glucocorticoid-Induced Expression of Tristetraprolin in MDA-MB-231 Breast Cancer Cells.

The mRNA destabilizing factor tristetraprolin (TTP) functions as a tumor suppressor by down-regulating cancer-associated genes. TTP expression is significantly reduced in various cancers, which contributes to cancer processes. Enforced expression of TTP impairs tumorigenesis and abolishes maintenance of the malignant state, emphasizing the need to identify a TTP inducer in cancer cells. To search for novel candidate agents for inducing TTP in cancer cells, we screened a library containing 1019 natural compounds using MCF-7 breast cancer cells transfected with a reporter vector containing the TTP promoter upstream of the luciferase gene. We identified one molecule, of which the enantiomers are betamethasone 21-phosphate (BTM-21-P) and dexamethasone 21-phosphate (BTM-21-P), as a potent inducer of TTP in cancer cells. We confirmed that BTM-21-P, DXM-21-P, and dexamethasone (DXM) induced the expression of TTP in MDA-MB-231 cells in a glucocorticoid receptor (GR)-dependent manner. To identify potential pathways linking BTM-21-P and DXM-21-P to TTP induction, we performed an RNA sequencing-based transcriptome analysis of MDA-MB-231 cells at 3 h after treatment with these compounds. A heat map analysis of FPKM expression showed a similar expression pattern between cells treated with the two compounds. The KEGG pathway analysis results revealed that the upregulated DEGs were strongly associated with several pathways, including the Hippo signaling pathway, PI3K-Akt signaling pathway, FOXO signaling pathway, NF-κB signaling pathway, and p53 signaling pathway. Inhibition of the FOXO pathway using a FOXO1 inhibitor blocked the effects of BTM-21-P and DXM-21-P on the induction of TTP in MDA-MB-231 cells. We found that DXM enhanced the binding of FOXO1 to the TTP promoter in a GR-dependent manner. In conclusion, we identified a natural compound of which the enantiomers are DXM-21-P and BTM-21-P as a potent inducer of TTP in breast cancer cells. We also present new insights into the role of FOXO1 in the DXM-21-P- and BTM-21-P-induced expression of TTP in cancer cells.

DRG2 Depletion Promotes Endothelial Cell Senescence and Vascular Endothelial Dysfunction.

Endothelial cell senescence is involved in endothelial dysfunction and vascular diseases. However, the detailed mechanisms of endothelial senescence are not fully understood. Here, we demonstrated that deficiency of developmentally regulated GTP-binding protein 2 (DRG2) induces senescence and dysfunction of endothelial cells. DRG2 knockout (KO) mice displayed reduced cerebral blood flow in the brain and lung blood vessel density. We also determined, by Matrigel plug assay, aorta ring assay, and in vitro tubule formation of primary lung endothelial cells, that deficiency in DRG2 reduced the angiogenic capability of endothelial cells. Endothelial cells from DRG2 KO mice showed a senescence phenotype with decreased cell growth and enhanced levels of p21 and phosphorylated p53, γH2AX, senescence-associated ß-galactosidase (SA-ß-gal) activity, and senescence-associated secretory phenotype (SASP) cytokines. DRG2 deficiency in endothelial cells upregulated arginase 2 (Arg2) and generation of reactive oxygen species. Induction of SA-ß-gal activity was prevented by the antioxidant N-acetyl cysteine in endothelial cells from DRG2 KO mice. In conclusion, our results suggest that DRG2 is a key regulator of endothelial senescence, and its downregulation is probably involved in vascular dysfunction and diseases.

Developmentally regulated GTP-binding protein-2 regulates adipocyte differentiation.

Developmentally regulated GTP-binding protein 2 (DRG2) participates in the regulation of proliferation and differentiation of multiple cells. However, whether DRG2 regulates adipocyte differentiation and related metabolic control remains elusive. This study revealed increases in body weight and adiposity in DRG2 transgenic (Tg) mice overexpressing DRG2. Consistent with these results, DRG2 Tg mice showed increased expression of genes involved in adipogenesis and lipid metabolism in the white adipose tissue. DRG2 was also identified to control adipogenesis by cooperating with peroxisome proliferator activated receptor-γ (PPAR-γ) in cultured adipocytes. Overall, the findings of the current study suggest that DRG2 plays an active role in regulating adipocyte differentiation, and thus participates in the development of obesity during exposure to a fat-rich diet.

RNA-seq transcriptome analysis in flounder cells to compare innate immune responses to low- and high-virulence viral hemorrhagic septicemia virus.

Viral hemorrhagic septicemia virus (VHSV) is a rhabdovirus that causes high mortality in cultured flounder. Viral growth and virulence rely on the ability to inhibit the cellular innate immune response. In this study, we investigated differences in the modulation of innate immune responses of HINAE flounder cells infected with low- and high-virulence VHSV strains at a multiplicity of infection of 1 for 12 h and 24 h and performed RNA sequencing (RNA-seq)-based transcriptome analysis. A total of 193 and 170 innate immune response genes were differentially expressed by the two VHSV strains at 12 and 24 h postinfection (hpi), respectively. Of these, 73 and 77 genes showed more than a twofold change in their expression at 12 and 24 hpi, respectively. Of the genes with more than twofold changes, 22 and 11 genes showed high-virulence VHSV specificity at 12 and 24 hpi, respectively. In particular, IL-16 levels were more than two time higher and CCL20a.3, CCR6b, CCL36.1, Casp8L2, CCR7, and Trim46 levels were more than two times lower in high-virulence-VHSV-infected cells than in low-virulence-VHSV-infected cells at both 12 and 24 hpi. Quantitative PCR (qRT-PCR) confirmed the changes in expression of the ten mRNAs with the most significantly altered expression. This is the first study describing the genome-wide analysis of the innate immune response in VHSV-infected flounder cells, and we have identified innate immune response genes that are specific to a high-virulence VHSV strain. The data from this study can contribute to a greater understanding of the molecular basis of VHSV virulence in flounder.

Deficiency of Tristetraprolin Triggers Hyperthermia through Enhancing Hypothalamic Inflammation.

Tristetraprolin (TTP), an RNA-binding protein, controls the stability of RNA by capturing AU-rich elements on their target genes. It has recently been identified that TTP serves as an anti-inflammatory protein by guiding the unstable mRNAs of pro-inflammatory proteins in multiple cells. However, it has not yet been investigated whether TTP affects the inflammatory responses in the hypothalamus. Since hypothalamic inflammation is tightly coupled to the disturbance of energy homeostasis, we designed the current study to investigate whether TTP regulates hypothalamic inflammation and thereby affects energy metabolism by utilizing TTP-deficient mice. We observed that deficiency of TTP led to enhanced hypothalamic inflammation via stimulation of a variety of pro-inflammatory genes. In addition, microglial activation occurred in the hypothalamus, which was accompanied by an enhanced inflammatory response. In line with these molecular and cellular observations, we finally confirmed that deficiency of TTP results in elevated core body temperature and energy expenditure. Taken together, our findings unmask novel roles of hypothalamic TTP on energy metabolism, which is linked to inflammatory responses in hypothalamic microglial cells.

Brain-specific chemokine FAM19A5 induces hypothalamic inflammation.

The cytokine-like protein FAM19A5 is highly expressed in the brain, but little is known about its functions there. Here, we found that FAM19A5 was expressed in mouse hypothalamic cells expressing proopiomelanocortin (POMC) and neuropeptide Y (NPY)/agouti-related peptide (AgRP), and in the microglia. Tumor necrosis factor-α (TNF-α), which induces inflammatory sickness responses, greatly increased hypothalamic expression of FAM19A5. Knockdown of FAM19A5 expression resulted in decreased TNF-α-induced anorexia, body weight loss and TNF-α-induced expression of inflammatory factors. In contrast, intracerebroventricular administration of FAM19A5 induced anorexia, body weight loss and hyperthermia, together with increased expression of inflammatory factors. FAM19A5 injection also induced increases in c-fos activation and POMC mRNA level in hypothalamic POMC neurons. Together, these results suggest that FAM19A5 plays an important role in hypothalamic inflammatory responses.

Doxorubicin inhibits PD-L1 expression by enhancing TTP-mediated decay of PD-L1 mRNA in cancer cells.

Recent research revealed that doxorubicin (DOX) decreased expression of programmed death-ligand 1 (PD-L1) in cancer cells. However, the detailed mechanisms underlying this effect are not well established. Here, we demonstrate that doxorubicin down-regulates PD-L1 expression through induction of AU-rich element (ARE) binding protein tristetraprolin (TTP) in cancer cells. PD-L1 mRNA contain three AREs within its 3'UTR. Doxorubicin induced expression of TTP, increased TTP binding to the 3rd ARE of the PD-L1 3'UTR, and increased decay of PD-L1 mRNA. Inhibition of TTP abrogates the inhibitory effect of doxorubicin on PD-L1 expression. Our data suggest that TTP plays a key role in doxorubicin-mediated down-regulation of PD-L1 by enhancing degradation of PD-L1 mRNA in cancer cells.

Tristetraprolin posttranscriptionally downregulates PFKFB3 in cancer cells.

The enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases 3 (PFKFB3) catalyzes the first committed rate-limiting step of glycolysis and is upregulated in cancer cells. The mechanism of PFKFB3 expression upregulation in cancer cells has not been fully elucidated. The PFKFB3 3'-UTR is reported to contain AU-rich elements (AREs) that are important for regulating PFKFB3 mRNA stability. However, the mechanisms by which PFKFB3 mRNA stability is determined by its 3'-UTR are not well known. We demonstrated that tristetraprolin (TTP), an ARE-binding protein, has a critical function regulating PFKFB3 mRNA stability. Our results showed that PFKFB3 mRNA contains three AREs in the 3'-UTR. TTP bound to the 3rd ARE and enhanced the decay of PFKFB3 mRNA. Overexpression of TTP decreased PFKFB3 expression and ATP levels but increased GSH level in cancer cells. Overexpression of PFKFB3 cDNA without the 3'-UTR rescued ATP level and GSH level in TTP-overexpressing cells. Our results suggested that TTP post-transcriptionally downregulated PFKFB3 expression and that overexpression of TTP may contribute to suppression of glycolysis and energy production of cancer cells in part by downregulating PFKFB3 expression.

Function of astrocyte MyD88 in high-fat-diet-induced hypothalamic inflammation.

BACKGROUND: A growing body of evidence shows that hypothalamic inflammation is an important factor in the initiation of obesity. In particular, reactive gliosis accompanied by inflammatory responses in the hypothalamus are pivotal cellular events that elicit metabolic abnormalities. In this study, we examined whether MyD88 signaling in hypothalamic astrocytes controls reactive gliosis and inflammatory responses, thereby contributing to the pathogenesis of obesity. METHODS: To analyze the role of astrocyte MyD88 in obesity pathogenesis, we used astrocyte-specific Myd88 knockout (KO) mice fed a high-fat diet (HFD) for 16 weeks or injected with saturated free fatty acids. Astrocyte-specific gene expression in the hypothalamus was determined using real-time PCR with mRNA purified by the Ribo-Tag system. Immunohistochemistry was used to detect the expression of glial fibrillary acidic protein, ionized calcium-binding adaptor molecule 1, phosphorylated signal transducer and activator of transcription 3, and α-melanocyte-stimulating hormone in the hypothalamus. Animals' energy expenditure was measured using an indirect calorimetry system. RESULTS: The astrocyte-specific Myd88 KO mice displayed ameliorated hypothalamic reactive gliosis and inflammation induced by injections of saturated free fatty acids and a long-term HFD. Accordingly, the KO mice were resistant to long-term HFD-induced obesity and showed an improvement in HFD-induced leptin resistance. CONCLUSIONS: These results suggest that MyD88 in hypothalamic astrocytes is a critical molecular unit for obesity pathogenesis that acts by mediating HFD signals for reactive gliosis and inflammation.

FOXO1 functions in the regulation of nicotinamide phosphoribosyltransferase (Nampt) expression.

Here, we report that Forkhead Box O1 (FOXO1) protein, a tumor suppressor, regulates expression of nicotinamide phosphoribosyltransferase (Nampt) in human breast cancer MCF-7 cells. Nampt plays an important role in the regulation of cell growth, survival, DNA replication and repair, and angiogenesis in tumorigenesis. We revealed that FOXO1 directly inhibits Nampt expression via binding to FOXO1 binding domains in the 5'-flanking region of the nampt gene. Nampt expression was increased by insulin and downstream phosphatidylinositol 3-kinase (PI3K)/Akt signaling, which was inhibited by FOXO1 overexpression. Accordingly, we showed that FOXO1 is also involved in insulin signaling-induced cell survival and proliferation in MCF-7 cells. These results suggest that FOXO1 plays an important role in human breast cancer cells by regulating nampt gene expression.

CO ameliorates endothelial senescence induced by 5-fluorouracil through SIRT1 activation.

Endothelial senescence is the main risk factor that contributes to vascular dysfunction and the progression of vascular disease. Carbon monoxide (CO) plays an important role in preventing vascular dysfunction and in maintaining vascular physiology or homeostasis. The application of exogenous CO has been shown to confer protection in several models of cardiovascular injury or disease, including hypertension, atherosclerosis, balloon-catheter injury, and graft rejection. However, the mechanism by which CO prevents endothelial senescence has been largely unexplored. The aim of this study was to evaluate the effects of CO on endothelial senescence and to investigate the possible mechanisms underlying this process. We measured the levels of senescence-associated-ß-galactosidase activity, senescence-associated secretory phenotype, reactive oxygen species (ROS) production, and stress granule in human umbilical vein endothelial cells and the WI-38 human diploid fibroblast cell line. We found that 5-fluorouracil (5FU)-induced ROS generation was inhibited by CO-releasing molecules (CORM)-A1 treatment, and endothelial senescence induced by 5FU was attenuated by CORM-A1 treatment. The SIRT1 inhibitor EX527 reversed the inhibitory effect of CO on the 5FU-induced endothelial senescence. Furthermore, SIRT1 deficiency abolished the stress granule formation by CO. Our results suggest that CO alleviates the endothelial senescence induced by 5FU through SIRT1 activation and may hence have therapeutic potential for the treatment of vascular diseases.

Immune biomarkers in maternal plasma to identify histologic chorioamnionitis in women with preterm labor.

PURPOSE: To determine whether various selected immune-related proteins in maternal plasma, alone or in combination, can predict histologic chorioamnionitis (HCA) in women with preterm labor, and to compare the predictive abilities of these biomarkers with that of serum C-reactive protein (CRP). METHODS: This retrospective cohort study included 74 consecutive women with preterm labor (23-34 gestational weeks) who delivered within 96 h of blood sampling. Their serum CRP levels were also measured. The stored maternal plasma was assayed for interleukin (IL)-6, matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinases (TIMP)-1, angiopoietin-2, S100 A8/A9, CXCL14, APRIL, and insulin-like growth factor-binding protein-2 (IGFBP-2), using ELISA kits. The primary outcome measure was HCA. RESULTS: HCA was detected in 59.4% (44/74) of women. Women with HCA had a significantly lower median gestational age at sampling and plasma IGFBP-2 level, and higher median plasma IL-6 and S100 A8/A9 levels than those without HCA. In multivariable analysis, high plasma IL-6 and low plasma IGFBP-2 levels were independently associated with the occurrence of HCA. However, the sensitivities, specificities, and areas under the curve of plasma IL-6, S100 A8/A9, and IGFBP-2, alone or in combination, were similar to or lower than those of serum CRP, for detecting HCA. CONCLUSIONS: Our data suggest that plasma IL-6, S100 A8/A9, and IGFBP-2 could be potential novel biomarkers for predicting HCA in women with PTL; however, elevated plasma levels of these biomarkers, alone or in combination, do not predict HCA better than serum CRP.

DRG2 Deficient Mice Exhibit Impaired Motor Behaviors with Reduced Striatal Dopamine Release.

Developmentally regulated GTP-binding protein 2 (DRG2) was first identified in the central nervous system of mice. However, the physiological function of DRG2 in the brain remains largely unknown. Here, we demonstrated that knocking out DRG2 impairs the function of dopamine neurons in mice. DRG2 was strongly expressed in the neurons of the dopaminergic system such as those in the striatum (Str), ventral tegmental area (VTA), and substantia nigra (SN), and on neuronal cell bodies in high-density regions such as the hippocampus (HIP), cerebellum, and cerebral cortex in the mouse brain. DRG2 knockout (KO) mice displayed defects in motor function in motor coordination and rotarod tests and increased anxiety. However, unexpectedly, DRG2 depletion did not affect the dopamine (DA) neuron population in the SN, Str, or VTA region or dopamine synthesis in the Str region. We further demonstrated that dopamine release was significantly diminished in the Str region of DRG2 KO mice and that treatment of DRG2 KO mice with l-3,4-dihydroxyphenylalanine (L-DOPA), a dopamine precursor, rescued the behavioral motor deficiency in DRG2 KO mice as observed with the rotarod test. This is the first report to identify DRG2 as a key regulator of dopamine release from dopamine neurons in the mouse brain.

CK2 downregulation induces senescence-associated heterochromatic foci formation through activating SUV39h1 and inactivating G9a.

Cellular senescence is an irreversible form of cell cycle arrest and senescent cells have a unique gene expression profile that is frequently accompanied by senescence-associated heterochromatic foci (SAHF). Here, we present evidence that CK2 downregulation induces trimethylation of histone H3 Lys 9 (H3K9me3), selective binding of HP1γ to H3K9me3, formation of SAHF, and reduction of cyclin D1 expression in HCT116 and MCF-7 cells. CK2 downregulation-mediated H3K9me3 is associated with induction of H3K9 trimethylase SUV39h1 as well as reduction of H3K9 dimethylase G9a and GLP in cells. In addition, Pharmacological inhibition of SUV39h1 and G9a overexpression significantly attenuated induction of senescence-associated ß-galactosidase (SA-ß-gal) activity, H3K9me3 and SAHF formation in CK2-downregulated cells. Moreover, CK2 downregulation induced H3K9me3 in nematodes. Taken together, these results demonstrate that CK2 downregulation leads to H3K9me3 and SAHF formation by increasing SUV39h1 and decreasing G9a.