microRNAs (miRNAs) are a group of highly conserved small non-coding RNAs that were found to enhance mRNA degradation or inhibit post-transcriptional translation. Accumulating evidence indicates that miRNAs contribute to tumorigenesis and cancer metastasis. microRNA-210 has been largely studied in the past several years and has been identified as a major miRNA induced under hypoxia. A variety of miR-210 targets have been identified pointing to its role, not only in mitochondrial metabolism, but also in angiogenesis, the DNA damage response, cell proliferation, and apoptosis. Based on earlier research findings, this review aims to provide a current overview on the involvement of miRNA-210 in biological processes and diseases.

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Protein kinases C (PKCs) are a family of serine/threonine kinases which act as key regulators in cell cycle progression and differentiation. Studies of the involvement of PKCs in cell proliferation showed that their role is dependent on cell models, cell cycle phases, timing of activation and localization. Indeed, PKCs can positively and negatively act on it, regulating entry, progression and exit from the cell cycle. In particular, the targets of PKCs resulted to be some of the key proteins involved in the cell cycle including cyclins, cyclin-dependent kinases (Cdks), Cip/Kip inhibitors and lamins. Several findings described roles for PKCs in the regulation of G₁/S and G₂/M checkpoints. As a matter of fact, data from independent laboratories demonstrated PKC-related modulations of cyclins D, leading to effects on the G₁/S transition and differentiation of different cell lines. Moreover, interesting data were published on PKC-mediated phosphorylation of lamins. In addition, PKC isoenzymes can accumulate in the nuclei, attracted by different stimuli including diacylglycerol (DAG) fluctuations during cell cycle progression, and target lamins, leading to their disassembly at mitosis. In the present paper, we briefly review how PKCs could regulate cell proliferation and differentiation affecting different molecules related to cell cycle progression.

Inflammation is widely recognized as contributing to the pathology of acute and chronic neurodegenerative conditions. Microglial cells are pathologic sensors in the brain and activated microglia have been viewed as detrimental. Leukotriene, including cysteinylleukotrienes (CysLTs) are suggested to be involved in brain inftammation and neurological diseases andATP, by its receptors is a candidate for microglia activation.A23187 (l0f1M) stimulated microglia to co-release CysLTs and [3H]adenine based purines ([3H]ABPs), mainly ATP. The biosynthetic production of CysLTs was abolished by 10f1MMK-886, an inhibitor of 5-lipoxygenase-activating protein activity. RT-PCR analysis showed that microglia expressed both CysLT I / CysLT 2 receptors, P 2Y1 ATPreceptors and several members of the ATP binding cassette (ABC) transporters including MRP1, MRP4 and Pgpo The increase in [Ca 2+]i elicited by LTD4 (0.1 f1M) and 2MeSATP (l00J.1M), agonists for CysLT-and P 2Y1 -receptors, was abolished by the respective antagonists, BAYu9773 (0.5 f1M) and suramin (50 f1M). The stimulation of both receptor subtypes, induced a concomitant increase in the release of both [3H]ABPs and CysLTs that was blocked by the antagonists and significantly reduced by a cocktail ofABC transporter inhibitors, BAPTAIAM (intracellular Ca2+ chelator) and staurosporine (0.1 f1M, PKC blocker). P2Y antagonist was unable to antagonise the effects ofLTD 4 and BAYu9773 did not reduce the effects of2MeSATP. These data suggest that: i) the efffux of purines and cysteinyl-leukotrienes is specifically and independently controlled by the two receptor types, ii) calcium, PKC and the ABC transporter system can reasonably be considered common mechanisms underlying the release ofABPs and CysLTs from microglia. The blockade ofP 2Y1 orCysLT/CysLT 2 receptors by specific antagonists that abolished the raise in [Ca"]! and drastically reduced the concomitant efffux of both compounds, as well as the effects ofBAPTA and staurosporine support this hypothesis. In conclusion, the data of the present study suggest a cross talk between the purine and leukotriene systems in a possible autocrine/paracrine control ofthe microglia-mediated initiation and progression of an inftammatory response.Proinflammatory products of 5-lipoxygenase (5-LO) pathway, including cysteinylleukotrienes (LTC4, LTD4, LTE4) are suggested to be involved in brain inflammation and neurological diseases. In aging brain and in Alzheimer's disease an increase in the activity of 5-LO has been shown (41, 57). The inhibition of the enzyme or 5-LO activating protein (FLAP) reduced the microglia-mediated toxicity towards neuronal cells, whereas the toxicity was enhanced by the cysteinyl leukotriene LTD4 (35).

Polyphosphoinositides (PPIns) are a family of seven lipid messengers that regulate a vast array of signalling pathways to control cell proliferation, migration, survival and differentiation. PPIns are differentially present in various sub-cellular compartments and, through the recruitment and regulation of specific proteins, are key regulators of compartment identity and function. Phosphoinositides and the enzymes that synthesise and degrade them are also present in the nuclear membrane and in nuclear membraneless compartments such as nuclear speckles. Here we discuss how PPIns in the nucleus are modulated in response to external cues and how they function to control downstream signalling. Finally we suggest a role for nuclear PPIns in liquid phase separations that are involved in the formation of membraneless compartments within the nucleus.

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Phosphatidylinositol (PI) metabolism represents the core of a network of signaling pathways which modulate many cellular functions including cell proliferation, cell differentiation, apoptosis, and membrane trafficking. An array of kinases, phosphatases, and lipases acts on PI creating an important number of second messengers involved in different cellular processes. Although, commonly, PI signaling was described to take place at the plasma membrane, many evidences indicated the existence of a PI cycle residing in the nuclear compartment of eukaryotic cells. The discovery of this mechanism shed new light on many nuclear functions, such as gene transcription, DNA modifications, and RNA expression. As these two PI cycles take place independently of one another, understanding how nuclear lipid signaling functions and modulates nuclear output is fundamental in the study of many cellular processes. J. Cell. Physiol. 231: 1645-1655, 2016. © 2015 Wiley Periodicals, Inc.