Role of cancerous inhibitor of protein phosphatase 2A in the regulation of T-cell response

T helper (Th) cell subsets with distinct functions are a critical component of the adaptive immune system. Th17 cells secrete interleukin 17 (IL-17) and provide host defense against pathogens. However, dysregulated Th17 response plays an essential role in the development of several autoimmune and inflammatory pathologies. Cancerous inhibitor of protein phosphatase 2A (CIP2A) modulates protein phosphatase 2A (PP2A) activity in cancer cells and neurological disorders. Accordingly, it is a promising target for therapy. However, to exploit the therapeutic potential of CIP2A, a better understanding of the physiological functions of CIP2A in immune cells is required. The doctoral thesis investigated CIP2A functions in regulating CD4+ T-cell activation and differentiation, particularly Th17 cells. The study showed that T-cell activation induces CIP2A, and its absence hampers T-cell activation. In Th17 cells, CIP2A depletion enhances IL17A expression and STAT3 phosphorylation. The transcriptome analysis showed CIP2A siRNA silencing upregulates many Th17-specific genes. The STAT3 interactome indicated CIP2A controls acylglycerol kinase (AGK) interaction with STAT3 and therefore modulates STAT3 phosphorylation and IL17A expression in Th17 cells. Furthermore, we performed the CIP2A protein interactome in Th17 cells. In addition to the CIP2A known interactor PP2A, we identified many novel protein interactions of CIP2A. For the first time, we identified CIP2A interaction with protein phosphatase PP1. Moreover, the study suggested the role of CIP2A in many pathways. Hence, this thesis provides an insight into CIP2A’s functions in immune cell regulation.CIP2A:n vaikutus T-solujen vasteen säätelyssä T-auttajasolujen (Th-solujen) alatyypit ovat keskeisiä adaptiivisen immuunijärjestelmän toiminnalle. Interleukiini-17-proteiinia (IL-17) tuottavat tyypin 17 auttaja T-lymfosyytit (Th17-solut) suojaavat elimistöä patogeeneiltä. Th17-solujen toiminnan häiriöt vaikuttavat useiden autoimmuunisairauksien ja tulehduksellisten tautien kehittymiseen. CIP2A-proteiini säätelee PP2A-molekyylin aktiivisuutta syöpäsoluissa ja on potentiaalinen syöpäterapian kohde. CIP2A-proteiinin terapeuttisen potentiaalin hyödyntäminen edellyttää CIP2A:n fysiologisten funktioiden parempaa ymmärtämistä immuunipuolustuksen soluissa. Tässä väitöskirjassa tutkittiin miten CIP2A säätelee CD4+ T-solujen aktivaatiota ja erilaistumista, keskittyen erityisesti Th17-soluihin. Osoitimme, että CIP2A:n indusoituu T-soluissa aktivaation seurauksena ja sen puuttuminen johtaa heikentyneeseen T-solujen aktivaatioon ja lisääntyneeseen Th17-solujen erilaistumiseen. CIP2A-hiljennetyissä Th17-soluissa IL17A-geenin ja monen muun Th17-soluille spesifisen geenin ilmeneminen oli lisääntynyt ja Th17- solujen erilaistumista ohjaava STAT3:n fosforylaatio oli pitkittynyt. Fosforyloituneen STAT3:n interaktomia tutkimalla paljastui, että CIP2Ahiljennetyissä soluissa acylglycerol-kinaasin ja STAT3:n vuorovaikutus säätelee STAT3:n fosforylaatiota ja IL17A:n ilmenemistä Th17-soluissa. Identifioimme useita uusia CIP2A-proteiinin kanssa vuorovaikuttavia tekijöitä karakterisoimalla CIP2A-interaktomin. Yksi näistä on PP1-proteiinifosfataasi. Väitöskirja valottaa CIP2A:n merkitystä immuunisolujen säätelyssä

Agricultural adaptation and climate change policy for crop production in Africa

Africa is considered among the most highly vulnerable regions to climate change because of extremes of drought, flooding, inappropriate land tenure systems, overdependence on rainfed agriculture, and widespread poverty. The impact of climate change is moderated by several factors such as access to land, inputs, credit, and markets. Thus, there is a critical need for decision makers at different levels in Africa to develop matching response strategies and policies to reduce vulnerability and foster resilient livelihood systems on a sustainable basis. The smallholder farming communities are inherently the most vulnerable to the negative impacts of climate change, and are always away from the advantage of any emerging opportunities due to resource constraints. About 65 % of national agricultural earnings in this continent is derived from the crop production of staple cereals, particularly maize. Due to shrinkage in cultivated area, production is also about 5–25 %, and the region’s need is more chronic for food and feed. The climate change challenge is aggravated by diminishing soil productivity and the decline in natural resources has affected the livelihood of rural and peri-urban communities. The communities have drawn on their indigenous knowledge systems with the support of local institutions and traditional social safety nets to adopt the various multiple stress factors related to climate change and variability. However, there is still limited empirical evidence on the robustness of these systems in support of social collaborations and resolving conflicts arising from the resource scarcity in the wake of climate change. Comprehensive policy frameworks are therefore required to expand the climate change adaptation horizons beyond the boundaries of current farming systems. For instance, the risk of crop-based enterprises has increased by deteriorating climatic conditions. There is much evidence of multiple stresses characterising the existing poverty traps for the predominantly rural communities, and challenges of chronic food insecurity, but no evidence on how current agriculture and climate change policy frameworks are able to address these multiple stress factors against the increasing risk and uncertainty of agriculture as a source of climate change adaptation. Currently, the majority of the farmers lives beyond the reach of markets, yet agricultural development policies are hinged on the principles of market participation. Transformation of these subsistence farms into commercially oriented and market-driven production systems will effectively call for structural and process changes in knowledge systems, technology development and delivery, institutions, and policies. The empirical research shows evidence of current and future impacts of climate change and variability on agricultural production systems, and their implications on the resilience of smallholder farming systems currently supporting the poorer and more vulnerable communities. Over the past decade, there has been a remarkable increase in awareness about climate change issues with diverse stakeholders, including policy makers. The lack of knowledge on the nature, magnitude, and direction of impacts at the indigenous community and national scales will likely continue to haunt decision-making processes regarding the development of robust strategies and policies to support adaptation. However, the regional agricultural sector has to undergo major transformation processes in order to meet emerging demands for adaptation. This may entail changes in the types and forms of information, knowledge, technologies, resource regimes, and institutions driving current production systems. There are still major knowledge gaps across disciplines on how local-level changes in climatic factors influence the socioecological processes that underpin agricultural production systems across spatial and temporal scales. Thus, it has been concluded that the policy making on climate change in Africa is not necessarily constrained by the lack of empirical evidence, but instead by the failure of policy makers to use available empirical evidence. The current failures in linking research to policy could be a major barrier to further research and development innovations for climate change adaptation. Evidence from limited climate change adaptation studies conducted with communities in the region revealed the importance of policy dialogue platforms as an integral part of research and development initiatives

PP2A and Its Inhibitors in Helper T-Cell Differentiation and Autoimmunity

Protein phosphatase 2A (PP2A) is a highly complex heterotrimeric Ser/Thr phosphatase that regulates many cellular processes. The role of PP2A as a tumor suppressor has been extensively studied and reviewed. However, emerging evidence suggests PP2A constrains inflammatory responses and is important in autoimmune and neuroinflammatory diseases. Here, we reviewed the existing literature on the role of PP2A in T-cell differentiation and autoimmunity. We have also discussed the modulation of PP2A activity by endogenous inhibitors and its small-molecule activators as potential therapeutic approaches against autoimmunity

Fluorescence microscopy on the biocompatibility of gentamicin-coated hydroxyapatite (HA) material on osteoblast

This study was carried out to observe the biocompatibility of gentamicin-coated hydroxyapatite (HA) on osteoblast using fluorescence microscopy. The specific objective was to observe the viability of the osteoblast on the gentamicin-coated hydroxyapatite (HA) and to determine the effect of the biomaterial coated with gentamicin on the osteoblast. Osteoblast cell lines were cultured and maintained in complete medium, 1:1 HAM's F12 Medium Dulbecco's modified Eagle's medium without phenol red (DMEM) and incubated at 37°C in a 5% CO 2. The cell lines were treated with different concentration of gentamicin-coated hydroxyapatite and the interactions of the antibiotic beads against osteoblast were tested using the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The MTT assay results indicated that varying concentrations of gentamicin coated HA from 0.1 mg/ml to 10 mg/ml did not significantly affect viability of osteoblast. By employing fluorescence microscopy, the morphology of osteoblast observed appeared red in color which indicated that the osteoblast was viable on biomaterial. The pore size of hydroxyapatite is between 150 to 350 nm. This preliminary result suggested that the gentamicin-coated HA had a good biocompatibility towards osteoblast

CD4<SUP>+</SUP> T Cell-derived novel peptide Thp5 induces interleukin-4 production in CD4<SUP>+</SUP> T cells to direct T helper 2 cell differentiation

The differentiation of naïve CD4+ T cells into T helper 2 (Th2) cells requires production of the cytokine IL-4 in the local microenvironment. It is evident that naïve/quiescently activated CD4+ T cells produce the IL-4 that drives Th2 cell differentiation. Because early production of IL-4 in naïve T cells leads to preferential Th2 cell differentiation, this process needs to be tightly regulated so as to avoid catastrophic and misdirected Th2 cell differentiation. Here, we show that Thp5, a novel peptide with structural similarity to vasoactive intestinal peptide, regulates production of early IL-4 in newly activated CD4+ T cells. Induction of IL-4 in CD4+ T cells by Thp5 is independent of the transcription factor STAT6 but dependent on ERK1/2 signaling. Furthermore, cytokines (IL-12 and TGF-β) that promote the differentiation of Th1 or Th17 cells inhibit Thp5 induction, thus suppressing Th2 cell differentiation. We further showed that Thp5 enhances Th2 responses and exacerbates allergic airway inflammation in mice. Taken together, our findings reveal that early activated CD4+ T cells produce Thp5, which plays a critical role as a molecular switch in the differentiation of Th cells, biasing the response toward the Th2 cell phenotype

Long Intergenic Noncoding RNA MIAT as a Regulator of Human Th17 Cell Differentiation

T helper 17 (Th17) cells protect against fungal and bacterial infections and are implicated in autoimmunity. Several long intergenic noncoding RNAs (lincRNA) are induced during Th17 differentiation, however, their contribution to Th17 differentiation is poorly understood. We aimed to characterize the function of the lincRNA Myocardial Infarction Associated Transcript (MIAT) during early human Th17 cell differentiation. We found MIAT to be upregulated early after induction of human Th17 cell differentiation along with an increase in the chromatin accessibility at the gene locus. STAT3, a key regulator of Th17 differentiation, directly bound to the MIAT promoter and induced its expression during the early stages of Th17 cell differentiation. MIAT resides in the nucleus and regulates the expression of several key Th17 genes, including IL17A, IL17F, CCR6 and CXCL13, possibly by altering the chromatin accessibility of key loci, including IL17A locus. Further, MIAT regulates the expression of protein kinase C alpha (PKC alpha), an upstream regulator of IL17A. A reanalysis of published single-cell RNA-seq data showed that MIAT was expressed in T cells from the synovium of RA patients. Our results demonstrate that MIAT contributes to human Th17 differentiation by upregulating several genes implicated in Th17 differentiation. High MIAT expression in T cells of RA patient synovia suggests a possible role of MIAT in Th17 mediated autoimmune pathologies

CIP2A Constrains Th17 Differentiation by Modulating STAT3 Signaling

Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is an oncogene and a potential cancer therapy target protein. Accordingly, a better understanding of the physiological function of CIP2A, especially in the context of immune cells, is a prerequisite for its exploitation in cancer therapy. Here, we report that CIP2A negatively regulates interleukin (IL)-17 production by Th17 cells in human and mouse. Interestingly, concomitant with increased IL-17 production, CIP2A-deficient Th17 cells had increased strength and duration of STAT3 phosphorylation. We analyzed the interactome of phosphorylated STAT3 in CIP2A-deficient and CIP2A-sufficient Th17 cells and indicated together with genome-wide gene expression profiling, a role of Acylglycerol Kinase (AGK) in the regulation of Th17 differentiation by CIP2A. We demonstrated that CIP2A regulates the strength of the interaction between AGK and STAT3, and thereby modulates STAT3 phosphorylation and expression of IL-17 in Th17 cells

Quantitative genome-scale metabolic modeling of human CD4+ T cell differentiation reveals subset-specific regulation of glycosphingolipid pathways

T cell activation, proliferation, and differentiation involve metabolic reprogramming resulting from the interplay of genes, proteins, and metabolites. Here, we aim to understand the metabolic pathways involved in the activation and functional differentiation of human CD4+ T cell subsets (T helper [Th]1, Th2, Th17, and induced regulatory T [iTreg] cells). Here, we combine genome-scale metabolic modeling, gene expression data, and targeted and non-targeted lipidomics experiments, together with in vitro gene knockdown experiments, and show that human CD4+ T cells undergo specific metabolic changes during activation and functional differentiation. In addition, we confirm the importance of ceramide and glycosphingolipid biosynthesis pathways in Th17 differentiation and effector functions. Through in vitro gene knockdown experiments, we substantiate the requirement of serine palmitoyltransferase (SPT), a de novo sphingolipid pathway in the expression of proinflammatory cytokines (interleukin [IL]-17A and IL17F) by Th17 cells. Our findings provide a comprehensive resource for selective manipulation of CD4+ T cells under disease conditions characterized by an imbalance of Th17/natural Treg (nTreg) cells.</p

Stereo-Selectivity of Human Serum Albumin to Enantiomeric and Isoelectronic Pollutants Dissected by Spectroscopy, Calorimetry and Bioinformatics

1–naphthol (1N), 2–naphthol (2N) and 8–quinolinol (8H) are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA). Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (Kb) of these pollutants to HSA were moderate (104–105 M−1). The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39–5.37 nm. The binding free energy (ΔG) in each case remains effectively the same for each site because of enthalpy–entropy compensation (EEC). The difference observed between ΔCpexp and ΔCpcalc are suggested to be caused by binding–induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H) in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants

CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A ( CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2A(HOZ)) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2A(HOZ) mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4(+) T-cells and CD8(+) effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell activation during adaptive immune response. These results also reveal CIP2A(HOZ) as a possible novel mouse model for studying the role of PP2A activity in immune regulation. On the other hand, the results also indicate that CIP2A targeting cancer therapies would not cause serious immunological side-effects.Peer reviewe