Novel Interventions on Comorbidities in Patients with Fetal Alcohol Spectrum Disorder (FASD): An Integrative Review.

Prenatal exposure to alcohol can cause Fetal Alcohol Spectrum Disorders (FASDs) after birth, encompassing a spectrum of physical, cognitive, and behavioral abnormalities. FASD represents a severe non-genetic disability avoidable through alcohol abstinence during pregnancy and when planning it. Clinical severity depends on alcohol impact, symptomatology, and resulting disabilities. FASD is a permanent disability with no recognized specific medical care. Conversely, secondary FASD-related disabilities can be symptomatically treated. This integrative review aims to provide information about the novel pharmacological treatments of FASD-associated comorbidities by selecting the last ten years of studies carried out on animals and humans. PRISMA guidelines were followed to search human/animal model studies of pharmacological interventions on FASD comorbidities, using different databases (PubMed, Cochrane, etc.). From 1348 articles, 44 met the criteria after full-text analysis. Firstly, all the reported studies point out that early diagnosis and tailored interventions are the principal tools to reduce FASD-related secondary disabilities, due to the fact that there is currently no approved pharmacological treatment for the tissue damage which produces FASD. Despite limitations in study designs and small sample sizes, these review results highlight how the treatment strategies of children with FASD have changed. In the past, studies focused on treating symptoms, but in the last years, researchers have turned their attention to the prevention targeting central nervous system embryogenesis. Novel treatments like choline and natural antioxidants and nutritional supplements are the most investigated treatments in humans with promising results. More follow-up studies need to be performed, to confirm and generalize reported efficacy to a wide sample size.

Survivin inhibition with YM155 ameliorates experimental pulmonary arterial hypertension.

Background: Imbalance between cell proliferation and apoptosis underlies the development of pulmonary arterial hypertension (PAH). Current vasodilator treatment of PAH does not target the uncontrolled proliferative process in pulmonary arteries. Proteins involved in the apoptosis pathway may play a role in PAH and their inhibition might represent a potential therapeutic target. Survivin is a member of the apoptosis inhibitor protein family involved in cell proliferation. Objectives: This study aimed to explore the potential role of survivin in the pathogenesis of PAH and the effects of its inhibition. Methods: In SU5416/hypoxia-induced PAH mice we assessed the expression of survivin by immunohistochemistry, western-blot analysis, and RT-PCR; the expression of proliferation-related genes (Bcl2 and Mki67); and the effects of the survivin inhibitor YM155. In explanted lungs from patients with PAH we assessed the expression of survivin, BCL2 and MKI67. Results: SU5416/hypoxia mice showed increased expression of survivin in pulmonary arteries and lung tissue extract, and upregulation of survivin, Bcl2 and Mki67 genes. Treatment with YM155 reduced right ventricle (RV) systolic pressure, RV thickness, pulmonary vascular remodeling, and the expression of survivin, Bcl2, and Mki67 to values similar to those in control animals. Lungs of patients with PAH also showed increased expression of survivin in pulmonary arteries and lung extract, and also that of BCL2 and MKI67 genes, compared with control lungs. Conclusion: We conclude that survivin might be involved in the pathogenesis of PAH and that its inhibition with YM155 might represent a novel therapeutic approach that warrants further evaluation.

A new negative feedback mechanism for MAPK pathway inactivation through Srk1 MAPKAP kinase.

The fission yeast mitogen-activated kinase (MAPK) Sty1 is essential for cell survival in response to different environmental insults. In unstimulated cells, Sty1 forms an inactive ternary cytoplasmatic complex with the MAPKK Wis1 and the MAPKAP kinase Srk1. Wis1 phosphorylates and activates Sty1, inducing the nuclear translocation of the complex. Once in the nucleus, Sty1 phosphorylates and activates Srk1, which in turns inhibits Cdc25 and cell cycle progression, before being degraded in a proteasome-dependent manner. In parallel, active nuclear Sty1 activates the transcription factor Atf1, which results in the expression of stress response genes including pyp2 (a MAPK phosphatase) and srk1. Despite its essentiality in response to stress, persistent activation of the MAPK pathway can be deleterious and induces cell death. Thus, timely pathway inactivation is essential to ensure an appropriate response and cell viability. Here, uncover a role for the MAPKAP kinase Srk1 as an essential component of a negative feedback loop regulating the Sty1 pathway through phosphorylation and inhibition of the Wis1 MAPKK. This feedback regulation by a downstream kinase in the pathway highlights an additional mechanism for fine-tuning of MAPK signaling. Thus, our results indicate that Srk1 not only facilitates the adaptation to stress conditions by preventing cell cycle progression, but also plays an instrumental role regulating the upstream kinases in the stress MAPK pathway.

Rat Model of Intra-articular Chondrocyte Xenotransplantation.

Current treatment options are not providing an adequate solution for cartilage defects. Articular cartilage lesions in particular are not able to repair spontaneously and progressively degenerate with an arthrosic pattern. Aiming to solve this pressing medical need, xenotransplantation of porcine chondrocytes could be developed as a new therapeutic approach. Xenotransplantation is gaining much attention, thanks to the advances in animal genetic engineering and progress in the characterization of the rejection mechanisms that prevent long-term graft survival. In this regard, our team has identified various targets for intervention that should be tested in a meaningful animal model to prove their relevance in rejection of xenogeneic cartilage. To this end, we have recently established a discordant xenotransplantation model by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats. This chapter describes this new model, which can be used to assess the immunoregulatory effect of a variety of strategies designed to inhibit rejection of xenogeneic PAC both at the humoral and cellular levels.

Biodistribution and Immunogenicity of Allogeneic Mesenchymal Stem Cells in a Rat Model of Intraarticular Chondrocyte Xenotransplantation.

Xenogeneic chondrocytes and allogeneic mesenchymal stem cells (MSC) are considered a potential source of cells for articular cartilage repair. We here assessed the immune response triggered by xenogeneic chondrocytes when injected intraarticularly, as well as the immunoregulatory effect of allogeneic bone marrow-derived MSC after systemic administration. To this end, a discordant xenotransplantation model was established by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats and monitoring the immune response. First, the fate of MSC injected using various routes was monitored in an in vivo imaging system. The biodistribution revealed a dependency on the injection route with MSC injected intravenously (i.v.) succumbing early after 24 h and MSC injected intraperitoneally (i.p.) lasting locally for at least 5 days. Importantly, no migration of MSC to the joint was detected in rats previously injected with PAC. MSC were then administered either i.v. 1 week before PAC injection or i.p. 3 weeks after to assess their immunomodulatory function on humoral and adaptive immune parameters. Anti-PAC IgM and IgG responses were detected in all PAC-injected rats with a peak at week 2 postinjection and reactivity remaining above baseline levels by week 18. IgG2a and IgG2b were the predominant and long-lasting IgG subtypes. By contrast, no anti-MSC antibody response was detected in the cohort injected with MSC only, but infusion of MSC before PAC injection temporarily augmented the anti-PAC antibody response. Consistent with a cellular immune response to PAC in PAC-injected rats, cytokine/chemokine profiling in serum by antibody array revealed a distinct pattern relative to controls characterized by elevation of multiple markers at week 2, as well as increases in proliferation in draining lymph nodes. Notably, systemic administration of allogeneic MSC under the described conditions did not diminish the immune response. IL-2 measurements in cocultures of rat peripheral blood lymphocytes with PAC indicated that PAC injection induced some T-cell hyporesponsiveness that was not enhanced in the cohorts additionally receiving MSC. Thus, PAC injected intraarticularly in Lewis rats induced a cellular and humoral immune response that was not counteracted by the systemic administration of allogeneic MSC under the described conditions.

The Cytosolic pH of Individual Saccharomyces cerevisiae Cells Is a Key Factor in Acetic Acid Tolerance.

It was shown recently that individual cells of an isogenic Saccharomyces cerevisiae population show variability in acetic acid tolerance, and this variability affects the quantitative manifestation of the trait at the population level. In the current study, we investigated whether cell-to-cell variability in acetic acid tolerance could be explained by the observed differences in the cytosolic pHs of individual cells immediately before exposure to the acid. Results obtained with cells of the strain CEN.PK113-7D in synthetic medium containing 96 mM acetic acid (pH 4.5) showed a direct correlation between the initial cytosolic pH and the cytosolic pH drop after exposure to the acid. Moreover, only cells with a low initial cytosolic pH, which experienced a less severe drop in cytosolic pH, were able to proliferate. A similar correlation between initial cytosolic pH and cytosolic pH drop was also observed in the more acid-tolerant strain MUCL 11987-9. Interestingly, a fraction of cells in the MUCL 11987-9 population showed initial cytosolic pH values below the minimal cytosolic pH detected in cells of the strain CEN.PK113-7D; consequently, these cells experienced less severe drops in cytosolic pH. Although this might explain in part the difference between the two strains with regard to the number of cells that resumed proliferation, it was observed that all cells from strain MUCL 11987-9 were able to proliferate, independently of their initial cytosolic pH. Therefore, other factors must also be involved in the greater ability of MUCL 11987-9 cells to endure strong drops in cytosolic pH.

Protein kinase Snf1 is involved in the proper regulation of the unfolded protein response in Saccharomyces cerevisiae.

Glc7 is the only catalytic subunit of the protein phosphatase type 1 in the yeast S. cerevisiae and, together with its regulatory subunits, is involved in many essential processes. Analysis of the non-essential mutants in the regulatory subunits of Glc7 revealed that the lack of Reg1, and no other subunit, causes hypersensitivity to unfolded protein response (UPR)-inducers, which was concomitant with an augmented UPR element-dependent transcriptional response. The Glc7-Reg1 complex takes part in the regulation of the yeast AMP-activated serine/threonine protein kinase Snf1 in response to glucose. We demonstrate in the present study that the observed phenotypes of reg1 mutant cells are attributable to the inappropriate activation of Snf1. Indeed, growth in the presence of limited concentrations of glucose, where Snf1 is active, or expression of active forms of Snf1 in a wild-type strain increased the sensitivity to the UPR-inducer tunicamycin. Furthermore, reg1 mutant cells showed a sustained HAC1 mRNA splicing and KAR2 mRNA levels during the recovery phase of the UPR, and dysregulation of the Ire1-oligomeric equilibrium. Finally, overexpression of protein phosphatases Ptc2 and Ptc3 alleviated the growth defect of reg1 cells under endoplasmic reticulum (ER) stress conditions. Altogether, our results reveal that Snf1 plays an important role in the attenuation of the UPR, as well as identifying the protein kinase and its effectors as possible pharmacological targets for human diseases that are associated with insufficient UPR activation.

Lack of the Glc7 phosphatase regulatory subunit Ypi1 activates the morphogenetic checkpoint.

Ypi1 is an essential regulator of the Saccharomyces cerevisiae Glc7 protein phosphatase. Although lack of Ypi1 results in a dramatic blockage in the G2/M cell cycle transition, with abnormally shaped large buds and short spindles, the molecular bases for this phenotype are still obscure. We report here that depletion of Ypi1 results in stabilization of the Pds1 securin, suggesting the activation of a G2/M checkpoint. Depletion of Ypi1 in cells deleted for MAD1/MAD2 or RAD9 still resulted in G2/M blockage, in spite that these cells lack key components of the spindle assembly and DNA damage checkpoints signaling, respectively. In contrast, deletion of SWE1, which encodes a protein kinase required for the morphogenesis checkpoint signaling, allowed passage through G2/M and recovery of normal cell morphology, although the cells did not proliferate. Depletion of Ypi1 caused stabilization of the Swe1 kinase, persistent phosphorylation of protein kinase Cdc28 at Y19, a landmark for morphogenesis checkpoint activation, and depletion of the Cdc11 septin, which explains the failure to form properly assembled septin rings at the bud necks. Deletion of SWE1 restored normal Cdc11 levels in the absence of Ypi1. These results demonstrate that Ypi1 plays an important role in the morphogenesis checkpoint, possibly by regulating Swe1.

Modulation of yeast alkaline cation tolerance by Ypi1 requires calcineurin.

Ypi1 was discovered as an essential protein able to act as a regulatory subunit of the Saccharomyces cerevisiae type 1 protein phosphatase Glc7 and play a key role in mitosis. We show here that partial depletion of Ypi1 causes lithium sensitivity and that high levels of this protein confer a lithium-tolerant phenotype to yeast cells. Remarkably, this phenotype was independent of the role of Ypi1 as a Glc7 regulatory subunit. Lithium tolerance in cells overexpressing Ypi1 was caused by a combination of increased efflux of lithium, mediated by augmented expression of the alkaline cation ATPase ENA1, and decreased lithium influx through the Trk1,2 high-affinity potassium transporters. Deletion of CNB1, encoding the regulatory subunit of the calcineurin phosphatase, blocked Ypi1-induced expression of ENA1, normalized Li(+) fluxes, and abolished the Li(+) hypertolerant phenotype of Ypi1-overexpressing cells. These results point to a complex role of Ypi1 on the regulation of cation homeostasis, largely mediated by the calcineurin phosphatase.

Use of yeast genetic tools to define biological roles of novel protein phosphatases.

Regulatable gene expression is a powerful genetic tool for analyzing the function of a given gene product. The use of tetracycline-regulatable promoters in yeast represents a substantial improvement over previously described methods for gene regulation. Here we show how this approach can be used to analyze the biological role of serine/threonine phosphatase catalytic or putative regulatory subunits by constructing chromosomal or plasmid-borne conditional mutants. This is particularly useful given the large variety of important biological processes performed by these of enzymes, often necessaries for cell survival, which makes in some cases infeasible the generation of null mutants.

YPI1 and SDS22 proteins regulate the nuclear localization and function of yeast type 1 phosphatase Glc7.

We have recently characterized Ypi1 as an inhibitory subunit of yeast Glc7 PP1 protein phosphatase. In this work we demonstrate that Ypi1 forms a complex with Glc7 and Sds22, another Glc7 regulatory subunit that targets the phosphatase to substrates involved in cell cycle control. Interestingly, the combination of equimolar amounts of Ypi1 and Sds22 leads to an almost full inhibition of Glc7 activity. Because YPI1 is an essential gene, we have constructed conditional mutants that demonstrate that depletion of Ypi1 leads to alteration of nuclear localization of Glc7 and cell growth arrest in mid-mitosis with aberrant mitotic spindle. These phenotypes mimic those produced upon inactivation of Sds22. The fact that progressive depletion of either Ypi1 or Sds22 resulted in similar physiological phenotypes and that both proteins inhibit the phosphatase activity of Glc7 strongly suggest a common role of these two proteins in regulating Glc7 nuclear localization and function.

Functional characterization of the yeast Ppz1 phosphatase inhibitory subunit Hal3: a mutagenesis study.

Saccharomyces cerevisiae Hal3 is a conserved protein that binds the carboxyl-terminal catalytic domain of the PP1c (protein phosphatase 1)-related phosphatase Ppz1 and potently inhibits its activity, thus modulating all of the characterized functions so far of the phosphatase. It is unknown how Hal3 binds to Ppz1 and inhibits its activity. Although it contains a putative protein phosphatase 1c binding-like sequence (263KLHVLF268), mutagenesis analysis suggests that this motif is not required for Ppz1 binding and inhibition. The mutation of the conserved His378 (possibly involved in dehydrogenase catalytic activity) did not impair Hal3 functions or Ppz1 binding. Random mutagenesis of the 228 residue-conserved central region of Hal3 followed by a loss-of-function screen allowed the identification of nine residues important for Ppz1-related Hal3 functions. Seven of these residues cluster in a relatively small region spanning from amino acid 446 to 480. Several mutations affected Ppz1 binding and inhibition in vitro, whereas changes in Glu460 and Val462 did not alter binding but resulted in Hal3 versions unable to inhibit the phosphatase. Therefore, there are independent Hal3 structural elements required for Ppz1 binding and inhibition. S. cerevisiae encodes a protein (Vhs3) structurally related to Hal3. Recent evidence suggests that both mutations are synthetically lethal. Surprisingly, versions of Hal3 carrying mutations that strongly affected Ppz1 binding or inhibitory capacity were able to complement lethality. In contrast, the mutation of His378 did not. This finding suggests that Hal3 may have both Ppz1-dependent and independent functions involving different structural elements.