ZC3H12B/MCPIP2, a new active member of the ZC3H12 family.

ZC3H12B is the most enigmatic member of the ZC3H12 protein family. The founding member of this family, Regnase-1/MCPIP1/ZC3H12A, is a well-known modulator of inflammation and is involved in the degradation of inflammatory mRNAs. In this study, for the first time, we characterized the properties of the ZC3H12B protein. We show that the biological role of ZC3H12B depends on an intact NYN/PIN RNase domain. Using RNA immunoprecipitation, experiments utilizing actinomycin D and ELISA, we show that ZC3H12B binds interleukin-6 (IL-6) mRNA in vivo, regulates its turnover, and results in reduced production of IL-6 protein upon stimulation with IL-1ß. We verified that regulation of IL-6 mRNA stability occurs via interaction of ZC3H12B with the stem-loop structure present in the IL-6 3'UTR. The IL-6 transcript is not the only target of ZC3H12B. ZC3H12B also interacts with other known substrates of Regnase-1 and ZC3H12D, such as the 3'UTRs of IER3 and Regnase-1, and binds IER3 mRNA in vivo. Using immunofluorescence, we examined the localization of ZC3H12B within the cell. ZC3H12B forms small, granule-like structures in the cytoplasm that are characteristic of proteins involved in mRNA turnover. The overexpression of ZC3H12B inhibits proliferation by stalling the cell cycle in the G2 phase. This effect of ZC3H12B is also NYN/PIN dependent. The analysis of the ZC3H12B mRNA level reveals its highest expression in the human brain and the neuroblastoma cell line SH-SY5Y, although the factors regulating its expression remain elusive. Down-regulation of ZC3H12B in SH-SY5Y cells by specific shRNAs results in up-regulation of ZC3H12B-target mRNAs.

Integrative genomics reveal a role for MCPIP1 in adipogenesis and adipocyte metabolism.

Obesity is considered a serious chronic disease, associated with an increased risk of developing cardiovascular diseases, non-alcoholic fatty liver disease and type 2 diabetes. Monocyte chemoattractant protein-1-induced protein-1 (MCPIP1) is an RNase decreasing stability of transcripts coding for inflammation-related proteins. In addition, MCPIP1 plays an important role in the regulation of adipogenesis in vitro by reducing the expression of key transcription factors, including C/EBPß. To elucidate the role of MCPIP1 in adipocyte biology, we performed RNA-Seq and proteome analysis in 3T3-L1 adipocytes overexpressing wild-type (WTMCPIP1) and the mutant form of MCPIP1 protein (D141NMCPIP1). Our RNA-Seq analysis followed by confirmatory Q-RT-PCR revealed that elevated MCPIP1 levels in 3T3-L1 adipocytes upregulated transcripts encoding proteins involved in signal transmission and cellular remodeling and downregulated transcripts of factors involved in metabolism. These data are consistent with our proteomic analysis, which showed that MCPIP1 expressing adipocytes exhibit upregulation of proteins involved in cellular organization and movement and decreased levels of proteins involved in lipid and carbohydrate metabolism. Moreover, MCPIP1 adipocytes are characterized by decreased level of insulin receptor, reduced insulin-induced Akt phosphorylation, as well as depleted Glut4 level and impaired glucose uptake. Overexpression of Glut4 in 3T3-L1 cells expressed WTMCPIP1 rescued adipogenesis. Interestingly, we found decreased level of MCPIP1 along with an increase in body mass index in subcutaneous adipose tissue. The presented data show a novel role of MCPIP1 in modulating insulin sensitivity in adipocytes. Overall, our findings demonstrate that MCPIP1 is an important regulator of adipogenesis and adipocyte metabolism.

MCPIP1/Regnase-1 Expression in Keratinocytes of Patients with Hidradenitis Suppurativa: Preliminary Results.

The pathogenesis of hidradenitis suppurativa (HS) is yet to be fully understood. However, inflammation is a key element in the development of skin lesions. The aim of this study was to evaluate the expression of monocyte chemotactic protein-1-induced protein-1 (MCPIP1) in the skin of patients suffering from HS. Skin biopsies of 15 patients with HS and 15 healthy controls were obtained and processed for immunohistochemistry, western blot, and real time PCR. The highest mean MCPIP1 mRNA expression was found in the inflammatory lesional skin of HS patients. It was significantly higher than MCPIP1 mRNA expression in the biopsies from both healthy controls and non-lesional skin of HS patients. Western blot analysis indicated that expression of MCPIP1 was elevated within both lesional and non-lesional skin compared to the healthy control. The increased MCPIP1 mRNA and protein expression level in HS lesions may indicate its possible role in the disease pathogenesis.

Fatty Acids and a High-Fat Diet Induce Epithelial-Mesenchymal Transition by Activating TGFß and ß-Catenin in Liver Cells.

Nonalcoholic fatty liver disease is defined as the accumulation of excessive fat in the liver in the absence of excessive alcohol consumption or any secondary cause. Although the disease generally remains asymptomatic, chronic liver inflammation leads to fibrosis, liver cirrhosis, and even to the development of hepatocellular carcinoma (HCC). Fibrosis results from epithelial-mesenchymal transition (EMT), which leads to dedifferentiation of epithelial cells into cells with a mesenchymal-like phenotype. During EMT, epithelial cells with high expression of E-cadherin, influenced by growth factors, cytokines, and inflammatory processes, undergo morphological changes via enhanced expression of, e.g., vimentin, fibronectin, and N-cadherin. An inducer of EMT and, consequently, of fibrosis development is transforming growth factor beta (TGFß), a pleiotropic cytokine associated with the progression of hepatocarcinogenesis. However, the understanding of the molecular events that direct the development of steatosis into steatohepatitis and liver fibrosis remains incomplete. Our study revealed that both prolonged exposure of hepatocarcinoma cells to fatty acids in vitro and high-fat diet in mice (20 weeks) result in inflammation. Prolonged treatment with fatty acids increased the levels of TGFß, MMP9, and ß-catenin, important EMT inducers. Moreover, the livers of mice fed a high-fat diet exhibited features of liver fibrosis with increased TGFß and IL-1 levels. Increased expression of IL-1 correlated with a decrease in monocyte chemoattractant protein-induced protein 1 (MCPIP1), a negative regulator of the inflammatory response that regulates the stability of proinflammatory transcripts encoding IL-1. Our study showed that a high-fat diet induced EMT by increasing the levels of EMT-activating transcription factors, including Zeb1, Zeb2, and Snail and changed the protein profile to a profile characteristic of the mesenchymal phenotype.

Anterior gradient 2 promotes tumorigenesis through upregulation of CCAAT-enhancer binding protein beta and hypoxia-inducible factor-2α and subsequent secretion of interleukin-6, interleukin-8, and vascular endothelial growth factor in the Caki-1 clear cell renal cell carcinoma cell line.

It has been previously established that hypoxia leads to tumor development, treatment resistance, and a poor prognosis. Under oxygen deprivation, hypoxia-inducible factors (HIFs) are stimulated to activate the genes necessary for tumor development in a low-oxygen environment. These genes encode regulators of angiogenesis, epithelial-mesenchymal transition, and cellular metabolism. A disulfide isomerase, anterior gradient 2 (AGR2), has been shown to increase hypoxia-inducible factor 1, alpha subunit (HIF-1α) stability in breast cancer. Our goal was to determine if AGR2 affects the level of transcription factor hypoxia-inducible factor 2, alpha subunit (HIF-2α). As a model, we used the clear cell renal cell carcinoma (ccRCC) cell line Caki-1. The cells were transduced with lentiviral vector (Tet-On) encoding AGR2. After induction of AGR2 expression, cells were grown under either hypoxic (0.5% O2 ) or normoxic (21% O2 ) conditions. Our data showed that AGR2 upregulated both HIF-1α and HIF-2α expression in Caki-1 cells increasing the expression of HIF-activated genes (glucose transporter 1, phosphoglycerate kinase 1, vascular endothelial growth factor A, and transforming growth factor-alpha) under the hypoxic conditions. Under the normoxic conditions, AGR2 strongly activated CCAAT-enhancer binding protein beta (C/EBPß). Upregulation of C/EBPß correlated with increased expression and secretion of the interleukin-6 and interleukin-8, inducing angiogenesis and inflammation in Caki-1 cells. In summary, our studies revealed that AGR2 has essential functions in ccRCC progression through upregulation of C/EBPß and HIF-2α expressions, which affects cell signaling and metabolism.

MCPIP1 RNase and Its Multifaceted Role.

Inflammation is an organism's physiological response to harmful septic and aseptic stimuli. This process begins locally through the influx of immune system cells to the damaged tissue and the subsequent activation and secretion of inflammatory mediators to restore homeostasis in the organism. Inflammation is regulated at many levels, and one of these levels is post-transcriptional regulation, which controls the half-life of transcripts that encode inflammatory mediators. One of the proteins responsible for controlling the amount of mRNA in a cell is the RNase monocyte chemoattractant protein-induced protein 1 (MCPIP1). The studies conducted so far have shown that MCPIP1 is involved not only in the regulation of inflammation but also in many other physiological and pathological processes. This paper provides a summary of the information on the role of MCPIP1 in adipogenesis, angiogenesis, cell differentiation, cancer, and skin inflammation obtained to date.

Ectopic overexpression of MCPIP1 impairs adipogenesis by modulating microRNAs.

Adipogenesis is a process of preadipocyte differentiation that requires action of numerous factors. Monocyte chemoattractant protein-1-induced protein 1 (MCPIP1) possesses the N-terminus of the PilT protein (PilT N-terminus or PIN domain) that has RNase properties. This protein degrades transcripts coding for inflammation and differentiation - related proteins. Moreover, MCPIP1 is a broad suppressor of the miRNA biogenesis. We previously found that MCPIP1 degrades transcript encoding CCAAT/Enhancer Binding Protein Beta (C/EBPß) and influences adipogenesis. Subsequently, we aimed to determine adipocyte miRNA expression profile in differentiating mouse preadipocytes, 3T3-L1, by overexpressing MCPIP1. Using Next-Generation Sequencing (NSG) we showed that MCPIP1 overexpression results in modulated levels of 58 miRNAs in adipocytes on day 2 of differentiation. Among them, 30 miRNAs showed significantly reduced levels and 28 showed increased levels in comparison to control. Approximately one third of the modulated miRNAs were not previously reported to be involved in adipocytes differentiation. Our analysis revealed that 24 down-regulated and 23 up-regulated miRNAs (at least 1.5-fold) influence 19 signaling pathways that are important for adipogenesis. Furthermore, reduced miRNA levels result in the up-regulation of their targets. By using luciferase reporter assay, we demonstrated that miR-32-5p and miR-9-3p directly target the 3'UTR region of Mapk8 and Tiam1, respectively. In addition, activation of MAP kinases pathway (JNK and p38), proposed as being regulated by down-regulated miRNAs, was higher in WTMCPIP1 than in D141NMCPIP1 or control 3T3-L1 adipocytes. Our results indicate a considerable impact of MCPIP1 on miRNAs levels and its significance in adipogenesis.

Intact NYN/PIN-Like Domain is Crucial for the Degradation of Inflammation-Related Transcripts by ZC3H12D.

ZC3H12D belongs to a recently discovered family of proteins containing four members of which the most studied and best described is the RNase ZC3H12A (MCPIP1/Regnase-1). ZC3H12A is a crucial negative regulator of inflammation. It accelerates the turnover of transcripts of a spectrum of proinflammatory cytokines, as well as its own mRNA. The biological role of ZC3H12D is less clear, although it was shown that this member of ZC3H12 family is also involved in the regulation of inflammation. Here, we show that ZC3H12A and ZC3H12D recognize a set of common target mRNAs encoding proteins that play important roles in the course of the inflammation. Similarly to ZC3H12A, ZC3H12D participates in the 3'UTR-dependent regulation of the turnover of mRNAs encoding interleukin-6 (IL-6), tumor necrosis factor (TNF), and immediate early response 3 gene (IER3). The ZC3H12A mRNA is also among the identified ZC3H12D targets. Using the combination of immunofluorescence with single molecule RNA fluorescence in situ hybridization (smRNA FISH) we have shown that ZC3H12D protein interacts with the ZC3H12A transcript. The direct binding of these two molecules in vivo was further confirmed by RNA immunoprecipitation. Simultaneously, overexpression of ZC3H12D increases the turnover rate of transcripts containing ZC3H12A 3'UTR. Using reporter gene assays we have confirmed that the Asp95 residue present in the NYN/PIN-like domain is crucial for ZC3H12D biological activity. We have also revealed that ZC3H12D recognizes the same structural elements present in the 3'UTRs of the investigated transcripts, as ZC3H12A. J. Cell. Biochem. 118: 487-498, 2017. © 2016 Wiley Periodicals, Inc.

MCPIP1 contributes to clear cell renal cell carcinomas development.

Monocyte Chemoattractant protein-induced protein 1 (MCPIP1), also known as Regnase-1, is encoded by the ZC3H12a gene, and it mediates inflammatory processes by regulating the stability of transcripts coding for proinflammatory cytokines and controlling activity of transcription factors, such as NF-κB and AP1. We found that MCPIP1 transcript and protein levels are strongly downregulated in clear cell renal cell carcinoma (ccRCC) samples, which were derived from patients surgically treated for renal cancer compared to surrounded normal tissues. Using Caki-1 cells as a model, we analyzed the role of MCPIP1 in cancer development. We showed that MCPIP1 expression depends on the proteasome activity; however, hypoxia and hypoxia inducible factor 2 alfa (HIF2α) are key factors lowering MCPIP1 expression. Furthermore, we found that MCPIP1 negatively regulates HIF1α and HIF2α levels and in the case of the last one, the mechanism is based on the regulation of the half time of transcript coding for HIF2α. Enhanced expression of MCPIP1 in Caki-1 cells results in a downregulation of transcripts encoding VEGFA, GLUT1, and IL-6. Furthermore, MCPIP1 decreases the activity of mTOR and protein kinase B (Akt) in normoxic conditions. Taken together, MCPIP1 contributes to the ccRCC development.

Monocyte Chemoattractant Protein-Induced Protein 1 Overexpression Modulates Transcriptome, Including MicroRNA, in Human Neuroblastoma Cells.

The recently discovered MCPIP1 (monocyte chemoattractant protein-induced protein 1), a multidomain protein encoded by the MCPIP1 (ZC3H12A) gene, has been described as a new differentiation factor, a ribonuclease, and a deubiquitination-supporting factor. However, its role in cancer is poorly recognized. Our recent analysis of microarrays data showed a lack of expression of the MCPIP1 transcript in primary neuroblastoma, the most common extracranial solid tumor in children. Additionally, enforced expression of the MCPIP1 gene in BE(2)-C cells caused a significant decrease in neuroblastoma proliferation and viability. Aim of the present study was to further investigate the role of MCPIP1 in neuroblastoma, using expression DNA microarrays and microRNA microarrays. Transient transfections of BE(2)-C cells were used for overexpression of either wild type of MCPIP1 (MCPIP1-wt) or its RN-ase defective mutant (MCPIP1-ΔPIN). We have analyzed changes of transcriptome and next, we have used qRT-PCR to verify mRNA levels of selected genes responding to MCPIP1 overexpression. Additionally, protein levels were determined for some of the selected genes. The choline transporter, CTL1, encoded by the SLC44A1 gene, was significantly repressed at the specific mRNA and protein levels and most importantly this translated into a decreased choline transport in MCPIP1-overexpressing cells. Then, we have found microRNA-3613-3p as the mostly altered in the pools of cells overexpressing the wild type MCPIP1. Next, we analyzed the predicted targets of the miR-3613-3p and validated them using qRT-PCR and western blot. These results indicate that the expression of miR-3613-3p might be regulated by MCPIP1 by cleavage of its precursor form.

Long Noncoding RNAs in Metabolic Syndrome Related Disorders.

Ribonucleic acids (RNAs) are very complex and their all functions have yet to be fully clarified. Noncoding genes (noncoding RNA, sequences, and pseudogenes) comprise 67% of all genes and they are represented by housekeeping noncoding RNAs (transfer RNA (tRNA), ribosomal RNA (rRNA), small nuclear RNA (snRNA), and small nucleolar RNA (snoRNA)) that are engaged in basic cellular processes and by regulatory noncoding RNA (short and long noncoding RNA (ncRNA)) that are important for gene expression/transcript stability. In this review, we summarize data concerning the significance of long noncoding RNAs (lncRNAs) in metabolic syndrome related disorders, focusing on adipose tissue and pancreatic islands.

Monocyte chemoattractant protein-induced protein 1 impairs adipogenesis in 3T3-L1 cells.

Monocyte chemoattractant protein-induced protein 1 (MCPIP1) encoded by the ZC3H12a gene (also known as Regnase-1) is involved in the regulation of degradation of mRNA of inflammatory modulators and for processing of pre-miRNA. These functions depend on the presence of the PIN domain. Moreover, MCPIP1 was described as a negative regulator of NF-κB and AP-1 signaling pathways although mechanisms underlying such activity remain unknown. We aimed at determining the role of MCPIP1 in adipogenesis. Here, we present evidence that Mcpip1 transcription is transiently activated during 3T3-L1 transition from pre- to adipocytes. However Mcpip1 protein expression is also strongly decreased at day one after induction of adipogenesis. Knockdown of Mcpip1 results in an upregulation of C/EBPß and PPARγ mRNAs, whereas overexpression of MCPIP1 reduces the level of both transcription factors and impairs adipogenesis. MCPIP1-dependend modulation of C/EBPß and PPARγ levels results in a modulation of the expression of downstream controlled genes. In addition, decreased C/EBPß, but not PPARγ, depends on the activity of the MCPIP1 PIN domain, which is responsible for RNase properties of this protein. Together, these data confirm that MCPIP1 is a key regulator of adipogenesis.

MCPIP1 contributes to the toxicity of proteasome inhibitor MG-132 in HeLa cells by the inhibition of NF-κB.

Recently, we have shown that the treatment of cells with proteasome inhibitor MG-132 results in the induction of expression of monocyte chemotactic protein-1 induced protein 1 (MCPIP1). MCPIP1 is a ribonuclease, responsible for the degradation of transcripts encoding certain pro-inflammatory cytokines. The protein is also known as an inhibitor of NF-κB transcription factor. Thanks to its molecular properties, MCPIP1 is considered as a regulator of inflammation, differentiation, and survival. Using siRNA technology, we show here that MCPIP1 expression contributes to the toxic properties of MG-132 in HeLa cells. The inhibition of proteasome by MG-132 and epoxomicin markedly increased MCPIP1 expression. While MG-132 induces HeLa cell death, down-regulation of MCPIP1 expression by siRNA partially protects HeLa cells from MG-132 toxicity and restores Nuclear factor-κB (NF-κB) activity, inhibited by MG-132 treatment. Inversely, overexpression of MCPIP1 decreased constitutive activity of NF-κB and limited the survival of HeLa cells, as we have shown in the previous study. Interestingly, although MG-132 decreased the expression of IκBα and increased p65 phosphorylation, the inhibition of constitutive NF-κB activity was observed in MG-132-treated cells. Since the elevated constitutive activity of NF-κB is one of the mechanisms providing increased survival of cancer cells, including HeLa cells, we propose that death-promoting properties of MCPIP1 in MG-132-treated HeLa cells may, at least partially, derive from the negative effect on the constitutive NF-κB activity.

Keratinocyte and myeloid MCPIP1 have distinct roles in maintaining skin homeostasis.

The skin is a complex organ, and the intricate network between keratinocytes and immune cells is critical for ensuring skin function. Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) is a ribonuclease that functions as a key negative modulator of inflammation. We previously reported that conditional deletion of MCPIP1 in keratinocytes (Mcpip1EKO) impairs skin integrity in adult mice. A similar phenotype was observed following the depletion of MCPIP1 in the myeloid compartment (Mcpip1MKO). The aim of this study was to develop a keratinocyte and myeloid double-MCPIP1 knockout mouse model to clarify the specific roles of myeloid and epidermal MCPIP1 in skin biology. Histological analyses indicated that the skin morphology changed after depletion of MCPIP1 in cells of myeloid origin as well as in keratinocytes. The thicknesses of the epidermal and subcutaneous fat layers increased in the mice with a loss of epidermal MCPIP1, whereas the loss of myeloid MCPIP1 had the opposite effect. In addition, both types of mice showed opposite responses to stimulation with 12-O-tetradecanoylphorbol-13-acetate. Transcriptomic profiling of whole-skin lysates revealed some common target transcripts in all the knockout mice. Further analyses revealed that distinct pathways are modulated following the loss of epidermal or myeloid MCPIP1. The skin morphology and inflammatory phenotype of keratinocyte and myeloid double-MCPIP1 knockout mice resembled those of mice with only keratinocyte-specific knockout of MCPIP1. Overall, myeloid and epidermal MCPIP1 play important but distinct roles in the modulation of skin-related processes.

An Atlas of the Hidradenitis Suppurativa Transcriptome.

INTRODUCTIONS: Hidradenitis suppurativa (HS) is a chronic inflammatory condition of the skin. Both genetic and environmental factors contribute to the risk of developing HS, but the pathogenesis of this disease is currently not fully understood. The aim of this study was to further current understanding of the molecular background of HS with the use of global transcriptome analyses. METHODS: Transcriptome profiling of perilesional and lesional skin of five patients with HS and six healthy control patients was performed by next-generation sequencing. Groups of differentially expressed genes characteristic of the skin of patients with HS were shortlisted by bioinformatic analysis. RESULTS: RNA sequencing followed by bioinformatic profiling revealed profound enrichment of inflammatory-related processes in both lesional and perilesional skin of patients with HS. There were, however, distinct differences in the gene expression profiles between the lesional and perilesional skin, with 1488 genes differentially expressed. Genes encoding typical proinflammatory cytokines were profoundly enriched within HS lesions. In contrast, those encoding mediators of extracellular matrix organization were highly expressed mostly in the perilesional area. CONCLUSIONS: Our study provides novel insights into the mechanisms underlying the pathogenesis of HS, and the results also have potential clinical implications in both diagnosis and therapeutics.

MCPIP1 Inhibits Hepatic Stellate Cell Activation in Autocrine and Paracrine Manners, Preventing Liver Fibrosis.

BACKGROUND & AIMS: Hepatic fibrosis is characterized by enhanced deposition of extracellular matrix (ECM), which results from the wound healing response to chronic, repeated injury of any etiology. Upon injury, hepatic stellate cells (HSCs) activate and secrete ECM proteins, forming scar tissue, which leads to liver dysfunction. Monocyte-chemoattractant protein-induced protein 1 (MCPIP1) possesses anti-inflammatory activity, and its overexpression reduces liver injury in septic mice. In addition, mice with liver-specific deletion of Zc3h12a develop features of primary biliary cholangitis. In this study, we investigated the role of MCPIP1 in liver fibrosis and HSC activation. METHODS: We analyzed MCPIP1 levels in patients' fibrotic livers and hepatic cells isolated from fibrotic murine livers. In vitro experiments were conducted on primary HSCs, cholangiocytes, hepatocytes, and LX-2 cells with MCPIP1 overexpression or silencing. RESULTS: MCPIP1 levels are induced in patients' fibrotic livers compared with their nonfibrotic counterparts. Murine models of fibrosis revealed that its level is increased in HSCs and hepatocytes. Moreover, hepatocytes with Mcpip1 deletion trigger HSC activation via the release of connective tissue growth factor. Overexpression of MCPIP1 in LX-2 cells inhibits their activation through the regulation of TGFB1 expression, and this phenotype is reversed upon MCPIP1 silencing. CONCLUSIONS: We demonstrated that MCPIP1 is induced in human fibrotic livers and regulates the activation of HSCs in both autocrine and paracrine manners. Our results indicate that MCPIP1 could have a potential role in the development of liver fibrosis.

Monocyte chemotactic protein-1-induced protein-1 (MCPIP1) is a novel multifunctional modulator of inflammatory reactions.

The generalized inflammatory response leads to activation of hundreds of genes transcribed in an established sequence in specialized cells. Transcriptome analysis of human monocyte-derived cells stimulated with IL-1beta or with monocyte chemotactic protein-1 (MCP-1) has led to the identification of a new inflammation-related gene ZC3H12A encoding a chain of 599 amino acids corresponding to a 66-kDa protein. The protein, given a provisional name of MCPIP1 (monocyte chemotactic protein-induced protein-1), is expressed in several human and murine tissues such as bone marrow, spleen, heart and placenta. In in vivo studies, mice with inactivated MCPIP1-encoding gene showed growth retardation, lymphadenopathy, splenomegaly and enhanced inflammatory symptoms. Principal molecular features of MCPIP1 include a single zinc finger motif, an RNase-like PIN domain and ubiquitin-binding domain. Reports from independent laboratories suggest that MCPIP1 may function also as a deubiquitinase. Although MCPIP1 is regarded by some authors as a new transcription factor or cell differentiation factor modulating angiogenesis or adipogenesis, its principal function appears to be downregulation of inflammatory responses through at least two independent mechanisms: increased degradation of cytokine mRNAs and inhibition of LPS- and IL-1-induced NF-kappaB signaling pathway. The interference with NF-kappaB activation is highly complex and includes TRAF6 and TANK interaction with the ubiquitin-associated (UBA) domain of MCPIP1. Purified MCPIP1 protein was reported to degrade specific mRNA and cleave K48- and K63-linked polyubiquitin chains. Although some structural features and the mechanism of action of MCPIP1 are not fully explained yet, its importance in the regulation of inflammatory reactions has been firmly established.

Effect of silver nanoparticles on human primary keratinocytes.

Silver nanoparticles (AgNPs) have many biological applications in biomedicine, biotechnology and other life sciences. Depending on the size, shape and the type of carrier, AgNPs demonstrate different physical and chemical properties. AgNPs have strong antimicrobial, antiviral and antifungal activity, thus they are used extensively in a range of medical settings, particularly in wound dressings but also in cosmetics. This study was undertaken to examine the potential toxic effects of 15 nm polyvinylpyrrolidone-coated AgNPs on primary normal human epidermal keratinocytes (NHEK). Cells were treated with different concentrations of AgNPs and then cell viability, metabolic activity and other biological and biochemical aspects of keratinocytes functioning were studied. We observed that AgNPs decrease keratinocyte viability, metabolism and also proliferatory and migratory potential of these cells. Moreover, longer exposure resulted in activation of caspase 3/7 and DNA damage. Our studies show for the first time, that AgNPs may present possible danger for primary keratinocytes, concerning activation of genotoxic and cytotoxic processes depending on the concentration.

Effects of the novel mitochondrial protein mimitin in insulin-secreting cells.

Mimitin, a novel mitochondrial protein, has been shown to act as a molecular chaperone for the mitochondrial complex I and to regulate ATP synthesis. During Type 1 diabetes development, pro-inflammatory cytokines induce mitochondrial damage in pancreatic ß-cells, inhibit ATP synthesis and reduce glucose-induced insulin secretion. Mimitin was expressed in rat pancreatic islets including ß-cells and decreased by cytokines. In the ob/ob mouse, a model of insulin resistance and obesity, mimitin expression was down-regulated in liver and brain, up-regulated in heart and kidney, but not affected in islets. To further analyse the impact of mimitin on ß-cell function, two ß-cell lines, one with a low (INS1E) and another with a higher (MIN6) mimitin expression were studied. Mimitin overexpression protected INS1E cells against cytokine-induced caspase 3 activation, mitochondrial membrane potential reduction and ATP production inhibition, independently from the NF-κB (nuclear factor κB)-iNOS (inducible NO synthase) pathway. Mimitin overexpression increased basal and glucose-induced insulin secretion and prevented cytokine-mediated suppression of insulin secretion. Mimitin knockdown in MIN6 cells had opposite effects to those observed after overexpression. Thus mimitin has the capacity to modulate pancreatic islet function and to reduce cytokine toxicity.

Depletion of Mcpip1 in murine myeloid cells results in intestinal dysbiosis followed by allergic inflammation.

MCPIP1 (called also Regnase-1) is a negative regulator of inflammation. Knockout of the Zc3h12a gene, encoding Mcpip1 in cells of myeloid origin (Mcpip1MKO), has a pathological effect on many organs. The aim of this study was to comprehensively analyze pathological changes in the skin caused by Mcpip1 deficiency in phagocytes with an emphasis on its molecular mechanism associated with microbiome dysbiosis. Mcpip1MKO mice exhibited spontaneous wound formation on the skin. On a molecular level, the Th2-type immune response was predominantly characterized by an increase in Il5 and Il13 transcript levels, as well as eosinophil and mast cell infiltration. Irritation by DNFB led to a more severe skin contact allergy in Mcpip1MKO mice. Allergic reactions on the skin were strongly influenced by gut dysbiosis and enhanced systemic dissemination of bacteria. This process was followed by activation of the C/EBP pathway in peripheral macrophages, leading to local changes in the cytokine microenvironment that promoted the Th2 response. A reduced bacterial load inhibited allergic inflammation, indicating the role of intestinal dysbiosis in the development of skin diseases. Our results clearly show that MCPIP1 in phagocytes is an essential negative regulator that controls the gut-skin axis.