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Regulatory T cells (Tregs) play fundamental roles in maintaining peripheral tolerance to prevent autoimmunity and limit legitimate immune responses, a feature hijacked in tumor microenvironments in which the recruitment of Tregs often extinguishes immune surveillance through suppression of T-effector cell signaling and tumor cell killing. The pharmacological tuning of Treg activity without impacting on T conventional (Tconv) cell activity would likely be beneficial in the treatment of various human pathologies. PIP4K2A, 2B, and 2C constitute a family of lipid kinases that phosphorylate PtdIns5P to PtdIns(4,5)P2. They are involved in stress signaling, act as synthetic lethal targets in p53-null tumors, and in mice, the loss of PIP4K2C leads to late onset hyperinflammation. Accordingly, a human single nucleotide polymorphism (SNP) near the PIP4K2C gene is linkedwith susceptibility to autoimmune diseases. How PIP4Ks impact on human T cell signaling is not known. Using ex vivo human primary T cells, we found that PIP4K activity is required for Treg cell signaling and immunosuppressive activity. Genetic and pharmacological inhibition of PIP4K in Tregs reduces signaling through the PI3K, mTORC1/S6, and MAPK pathways, impairs cell proliferation, and increases activation-induced cell death while sparing Tconv. PIP4K and PI3K signaling regulate the expression of the Treg master transcriptional activator FOXP3 and the epigenetic signaling protein Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1). Our studies suggest that the pharmacological inhibition of PIP4K can reprogram human Treg identity while leaving Tconv cell signaling and T-helper differentiation to largely intact potentially enhancing overall immunological activity.

The data and information presented here refer to the research article entitled: “Reactivating endogenous mechanisms of cardiac regeneration via paracrine boosting with the human amniotic fluid stem cell secretome” (Balbi et al., 2019, Apr 04). This dataset illustrates the in vitro paracrine effect exerted by the human amniotic fluid stem cell secretome on rodent neonatal cardiomyocytes, human endothelial progenitors and different subsets of cardiac progenitor cells. Cytokine/chemokine profiling of the human amniotic fluid stem cell secretome is provided as well. This data can provide useful insights in regenerative medicine as demonstrating the in vitro cardioprotective and proliferative secretory paracrine potential of human fetal stem cells. Keywords: Paracrine effect, Human amniotic fluid stem cells, Cardiac progenitor cells, Neonatal cardiomyocytes, Endothelial progenitors, Proliferation, Cardioprotection, Angiogenesis

The immune system is a complex network that acts to protect vertebrates from foreign microorganisms and carries out immunosurveillance to combat cancer. In order to avoid hyper-activation of the immune system leading to collateral damage tissues and organs and to prevent self-attack, the network has the intrinsic control mechanisms that negatively regulate immune responses. Central to this negative regulation are regulatory T (T-Reg) cells, which through cytokine secretion and cell interaction limit uncontrolled clonal expansion and functions of activated immune cells. Given that positive or negative manipulation of T-Regs activity could be utilised to therapeutically treat host versus graft rejection or cancer respectively, understanding how signaling pathways impact on T-Regs function should reveal potential targets with which to intervene. The phosphatidylinositol-3-kinase (PI3K) pathway controls a vast array of cellular processes and is critical in T cell activation. Here we focus on phosphoinositide 3-kinases (PI3Ks) and their ability to regulate T-Regs cell differentiation and function.

Background: The adult mammalian heart retains residual regenerative capability via endogenous cardiac progenitor cell (CPC) activation and cardiomyocyte proliferation. We previously reported the paracrine cardioprotective capacity of human amniotic fluid-derived stem cells (hAFS) following ischemia or cardiotoxicity. Here we analyse the potential of hAFS secretome fractions for cardiac regeneration and future clinical translation.Methods: hAFS were isolated from amniotic fluid leftover samples from prenatal screening. hAFS conditioned medium (hAFS-CM) was obtained following hypoxic preconditioning. Anti-apoptotic, angiogenic and proliferative effects were evaluated on rodent neonatal cardiomyocytes (r/mNVCM), human endothelial colony forming cells (hECFC) and human CPC. Mice undergoing myocardial infarction (MI) were treated with hAFS-CM, hAFS-extracellular vesicles (hAFS-EV), or EV-depleted hAFS-CM(hAFS-DM) by single intra-myocardial administration and evaluated in the short and long term.Results: hAFS-CM improved mNVCM survival under oxidative and hypoxic damage, induced Ca2+-dependent angiogenesis in hECFC and triggered hCPC and rNVCM proliferation. hAFS-CM treatment after MI counteracted scarring, supported cardiac function, angiogenesis and cardiomyocyte cell cycle progression in the long term. hAFS-DM had no effect. hAFS-CM and hAFS-EV equally induced epicardium WT1+CPC reactivation. Although no CPC cardiovascular differentiation was observed, our data suggests contribution to local angiogenesis by paracrine modulation. hAFS-EV alone were able to recapitulate all the beneficial effects exerted by hAFS-CM, except for stimulation of vessel formation.Conclusions: hAFS-CM and hAFS-EV can improve cardiac repair and trigger cardiac regeneration via paracrine modulation of endogenous mechanisms. While both formulations are effective in sustaining myocardial renewal, hAFS-CM retains higher pro-angiogenic potential, while hAFS-EV particularly enhances cardiac function. (c) 2019 Elsevier B.V. All rights reserved.

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.

Objective: To investigate whether exposure to inhibitors of gastric acidity, such as H2 blockers or proton pump inhibitors, can independently increase the risk of infections in very low birth weight (VLBW) preterm infants in the neonatal intensive care unit. Study design: This is a secondary analysis of prospectively collected data from a multicenter, randomized controlled trial of bovine lactoferrin (BLF) supplementation (with or without the probiotic Lactobacillus rhamnosus GG) vs placebo in prevention of late-onset sepsis (LOS) and necrotizing enterocolitis (NEC) in preterm infants. Inhibitors of gastric acidity were used at the recommended dosages/schedules based on the clinical judgment of attending physicians. The distribution of days of inhibitors of gastric acidity exposure between infants with and without LOS/NEC was assessed. The mutually adjusted effects of birth weight, gestational age, duration of inhibitors of gastric acidity treatment, and exposure to BLF were controlled through multivariable logistic regression. Interaction between inhibitors of gastric acidity and BLF was tested; the effects of any day of inhibitors of gastric acidity exposure were then computed for BLF-treated vs -untreated infants. Results: Two hundred thirty-five of 743 infants underwent treatment with inhibitors of gastric acidity, and 86 LOS episodes occurred. After multivariate analysis, exposure to inhibitors of gastric acidity remained significantly and independently associated with LOS (OR, 1.03; 95% CI, 1.008-1.067; P = .01); each day of inhibitors of gastric acidity exposure conferred an additional 3.7% odds of developing LOS. Risk was significant for Gram-negative (P < .001) and fungal (P = .001) pathogens, but not for Gram-positive pathogens (P = .97). On the test for interaction, 1 additional day of exposure to inhibitors of gastric acidity conferred an additional 7.7% risk for LOS (P = .003) in BLF-untreated infants, compared with 1.2% (P = .58) in BLF-treated infants. Conclusion: Exposure to inhibitors of gastric acidity is significantly associated with the occurrence of LOS in preterm VLBW infants. Concomitant administration of BLF counteracts this selective disadvantage. Trial registration: isrctn.org: ISRCTN53107700.

Diamond-Blackfan anemia (DBA) is an inherited disease characterized by pure erythroid aplasia. Thirty percent (30%) of patients display malformations, especially of the hands, face, heart, and urogenital tract. DBA has an autosomal dominant pattern of inheritance. De novo mutations are common and familial cases display wide clinical heterogeneity. Twenty-five percent (25%) of patients carry a mutation in the ribosomal protein (RP) S19 gene, whereas mutations in RPS24, RPS17, RPL35A, RPL11, and RPL5 are rare. These genes encode for structural proteins of the ribosome. A link between ribosomal functions and erythroid aplasia is apparent in DBA, but its etiology is not clear. Most authors agree that a defect in protein synthesis in a rapidly proliferating tissue, such as the erythroid bone marrow, may explain the defective erythropoiesis. A total of 77 RPS19 mutations have been described. Most are whole gene deletions, translocations, or truncating mutations (nonsense or frameshift), suggesting that haploinsufficiency is the basis of DBA pathology. A total of 22 missense mutations have also been described and several works have provided in vitro functional data for the mutant proteins. This review looks at the data on all these mutations, proposes a functional classification, and describes six new mutations. It is shown that patients with RPS19 mutations display a poorer response to steroids and a worse long-term prognosis compared to other DBA patients.