scholarly journals Drosophila DNA/RNA methyltransferase contributes to robust host defense in ageing animals by regulating sphingolipid metabolism

2018 ◽  
Author(s):  
Varada Abhyankar ◽  
Bhagyashree Kaduskar ◽  
Siddhesh S. Kamat ◽  
Deepti Deobagkar ◽  
Girish Ratnaparkhi
Keyword(s):  
Host Defense ◽  
Sphingolipid Metabolism ◽  
Storage Lipids ◽  
Age Dependent ◽  
Concomitant Reduction ◽  
Lyase Activity ◽  
Low Levels ◽  
S1p Lyase ◽  
Immune Defects ◽  
Lipid Imbalance

ABSTRACTDrosophila methyltransferase (Mt2) has been implicated in methylation of both DNA and tRNA. In this study, we demonstrate that loss of Mt2 activity leads to an age dependent decline of immune function in the adult fly. A newly eclosed adult has mild immune defects that exacerbate in a fifteen-day old Mt2−/− fly. The age dependent effects appear to be systemic, including disturbances in lipid metabolism, changes in cell shape of hemocytes and significant fold changes in levels of transcripts related to host defense. Lipid imbalance, as measured by quantitative lipidomics, correlates with immune dysfunction with high levels of immunomodulatory lipids, sphingosine-1phosphate (S1P) and ceramides, along with low levels of storage lipids. Activity assays on fly lysates confirm the age dependent increase in S1P and concomitant reduction of S1P lyase activity. We hypothesize that Mt2 functions to regulate genetic loci such as S1P lyase and this regulation is essential for robust host defense as the animal ages. Our study uncovers novel links between age dependent Mt2 function, innate immune response and lipid homeostasis.

scholarly journals Age-dependent Increases in Adrenal Cytochrome b5 and Serum 5-Androstenediol-3-sulfate

2016 ◽  
Vol 101 (12) ◽  
pp. 4585-4593 ◽  
Author(s):  
Juilee Rege ◽  
Shigehiro Karashima ◽  
Antonio M. Lerario ◽  
Joshua M. Smith ◽  
Richard J. Auchus ◽  
...  
Keyword(s):  
Cytochrome B5 ◽  
Serum Levels ◽  
Dehydroepiandrosterone Sulfate ◽  
Zona Fasciculata ◽  
Adrenocortical Cells ◽  
Normal Children ◽  
Age Related ◽  
Age Dependent ◽  
Lyase Activity ◽  
Liquid Chromatography Tandem Mass

Context: Adrenal production of dehydroepiandrosterone sulfate (DHEA-S) increases throughout childhood owing to expansion of the zona reticularis (ZR). ZR features cells with a steroidogenic phenotype distinct from that of the adjacent zona fasciculata, with higher expression of cytochrome b5 type A (CYB5A) and steroid sulfotransferase type 2A1 but decreased 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2). In addition to DHEA-S, three adrenal Δ5-steroid sulfates could provide additional tools to define adrenal maturation. Objective: This study sought to simultaneously measure serum levels of four adrenal Δ5-steroid sulfates, pregnenolone sulfate (Preg-S), 17α-hydroxypregnenolone sulfate (17OHPreg-S), DHEA-S, and 5-androstenediol-3-sulfate (Adiol-S) as a function of age and relate their production to the age-dependent adrenal localization of CYB5A. Participants and Methods: Δ5-steroid sulfates were quantified by liquid chromatography–tandem mass spectrometry in sera from 247 normal children (129 males,118 females) age 1.5–18 y and 42 adults (20 males, 22 females). Immunofluorescence localized HSD3B2 and CYB5A in normal adrenal glands from subjects age 2–35 y. Finally, HAC15 adrenocortical cells were transduced with lentiviral short hairpin RNA to suppress CYB5A expression. Results: Of the Δ5-steroid sulfates quantified, DHEA-S was most abundant. Adiol-S increased in parallel with DHEA-S. Steroid ratios (17OHPreg-S/DHEA-S) suggested increases in 17,20-lyase activity during childhood. Immunofluorescence analysis showed age-related increases in ZR CYB5A immunoreactivity. Furthermore, silencing CYB5A in HAC15 adrenocortical cells significantly reduced DHEA-S and Adiol-S production. Conclusion: Adiol-S shows a similar age-related increase to that of DHEA-S. This likely results from the childhood expansion of CYB5A-expressing ZR, which enhances 17,20-lyase activity and the production of DHEA-S and Adiol-S.

scholarly journals DAF-16 and SMK-1 Contribute to Innate Immunity During Adulthood in Caenorhabditis elegans

2020 ◽  
Vol 10 (5) ◽  
pp. 1521-1539 ◽  
Author(s):  
Daniel R. McHugh ◽  
Elena Koumis ◽  
Paul Jacob ◽  
Jennifer Goldfarb ◽  
Michelle Schlaubitz-Garcia ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune System ◽  
Caenorhabditis Elegans ◽  
Host Defense ◽  
Insulin Signaling ◽  
Bacterial Pathogens ◽  
C Elegans ◽  
Link Type ◽  
Age Dependent ◽  
Over Time

Aging is accompanied by a progressive decline in immune function termed “immunosenescence”. Deficient surveillance coupled with the impaired function of immune cells compromises host defense in older animals. The dynamic activity of regulatory modules that control immunity appears to underlie age-dependent modifications to the immune system. In the roundworm Caenorhabditis elegans levels of PMK-1 p38 MAP kinase diminish over time, reducing the expression of immune effectors that clear bacterial pathogens. Along with the PMK-1 pathway, innate immunity in C. elegans is regulated by the insulin signaling pathway. Here we asked whether DAF-16, a Forkhead box (FOXO) transcription factor whose activity is inhibited by insulin signaling, plays a role in host defense later in life. While in younger C. elegansDAF-16 is inactive unless stimulated by environmental insults, we found that even in the absence of acute stress the transcriptional activity of DAF-16 increases in an age-dependent manner. Beginning in the reproductive phase of adulthood, DAF-16 upregulates a subset of its transcriptional targets, including genes required to kill ingested microbes. Accordingly, DAF-16 has little to no role in larval immunity, but functions specifically during adulthood to confer resistance to bacterial pathogens. We found that DAF-16-mediated immunity in adults requires SMK-1, a regulatory subunit of the PP4 protein phosphatase complex. Our data suggest that as the function of one branch of the innate immune system of C. elegans (PMK-1) declines over time, DAF-16-mediated immunity ramps up to become the predominant means of protecting adults from infection, thus reconfiguring immunity later in life.

Survival characteristics of the free-living cercarial population of the ectoparasitic digenean Transversotrema patialensis (Soparker, 1924)

Parasitology ◽  
1975 ◽  
Vol 70 (3) ◽  
pp. 295-310 ◽  
Author(s):  
R. M. Anderson ◽  
P. J. Whitfield
Keyword(s):  
Mathematical Models ◽  
Life Span ◽  
Conceptual Understanding ◽  
Biological Processes ◽  
Energy Reserves ◽  
Age Dependence ◽  
Maximum Life Span ◽  
Free Living ◽  
Age Dependent ◽  
Low Levels

The survival characteristics of free-living cercarial populations of Transversotrema patialensis were described and shown to be age-dependent. The maximum life-span was found to be 44 h with a 50% survival at 26 h. Activity and infectivity of the larvae were also characterized by age-dependence, and were demonstrated to be closely correlated with one another. For individual cercariae, both activity and infectivity had dropped to extremely low levels many hours before death occurred. An attempt was made to interrelate activity and infectivity, in a theoretical manner, with the availability of energy reserves.Conceptual understanding of the biological processes involved was aided by the formulation of simple mathematical models.

Phenylalanine ammonia-lyase activity in soybean hypocotyls and leaves following infection with Phytophthora megasperma f.sp. glycinea

1988 ◽  
Vol 66 (1) ◽  
pp. 18-23 ◽  
Author(s):  
M. K. Bhattacharyya ◽  
E. W. B. Ward
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Symptom Development ◽  
Metabolic Processes ◽  
Phytophthora Megasperma ◽  
Lyase Activity ◽  
Abiotic Elicitor ◽  
Race 1 ◽  
Low Levels ◽  
Phenylalanine Ammonia Lyase Activity

Phenylalanine ammonia-lyase activity increased rapidly beginning 2 h after inoculation with Phytophthora megasperma (Drechs.) f.sp. glycinea (Hildeb.) Kuan & Erwin race 1 in unwounded hypocotyls of soybean cv. Harosoy 63 (resistant) but did not change significantly in cv. Harosoy (susceptible). Small increases in phenylalanine ammonia-lyase activity also were caused by wounding. Activity increased more slowly in hypocotyls (cv. Harosoy 63) wounded just before inoculation than in intact inoculated hypocotyls, but most activity developed in hypocotyls wounded 12 h before inoculation. There were comparable effects of wounding on symptom development. Trifoliolate leaves of 14-day-old cv. Harosoy 63 plants are resistant, but trifoliolate leaves of 12-day-old cv. Harosoy 63 plants and of 14-day-old cv. Harosoy plants are susceptible to race 1. Increases in phenylalanine ammonia-lyase activity following inoculation were demonstrated only in 14-day-old Harosoy 63 plants but not until 24–36 h after the inoculation. Significant accumulation of glyceollin occurred by 24 h. Susceptible trifoliolate leaves of 12-day-old cv. Harosoy 63 plants produced only low levels of glyceollin following either infection or treatment with the abiotic elicitor AgNO3, whereas trifoliolate leaves of 14-day-old cv. Harosoy plants produced high levels of glyceollin in response to AgNO3. It is concluded that trifoliolate leaves of 12-day-old, as opposed to 14-day-old, cv. Harosoy 63 plants have not developed mechanisms that trigger responses to either infection or the abiotic elicitor or they are deficient in metabolic processes that support glyceollin biosynthesis or other defense-related responses.

Extreme Leukoreduction of Major Histocompatibility Complex Class II Positive B Cells Enhances Allogeneic Platelet Immunity

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 713-720 ◽  
Author(s):  
John W. Semple ◽  
Edwin R. Speck ◽  
Donna Cosgrave ◽  
Alan H. Lazarus ◽  
Victor S. Blanchette ◽  
...  
Keyword(s):  
B Cells ◽  
Mhc Class Ii ◽  
Scid Mouse ◽  
Mononuclear Cells ◽  
Class Ii ◽  
Histocompatibility Complex ◽  
Age Dependent ◽  
Low Levels ◽  
Definitive Role

In a murine model of platelet alloimmunization, we examined the definitive role that mononuclear cells (MC) have in modulating platelet immunity by using platelets from severe combined immunodeficient (SCID) mice. CB.17 (H-2d) SCID or BALB/c (H-2d) mouse platelets were transfused weekly into fully allogeneic CBA (H-2k) mice and antidonor antibodies measured by flow cytometry. MC levels in BALB/c platelets were 1.1 ± 0.6/μL and SCID mouse platelets could be prepared to have significantly lower (<0.05/μL) MC numbers. Transfusions with 108 BALB/c platelets (containing ≈100 MC/transfusion) stimulated IgG antidonor antibodies in 100% of the recipients by the fifth transfusion, whereas 108 SCID mouse platelets (containing ≈5 MC/transfusion) stimulated higher-titered IgG alloantibodies by the second transfusion. When titrations of BALB/c peripheral blood MC were added to the SCID mouse platelets, levels approaching 1 MC/μL reduced SCID platelet immunity to levels similar to BALB/c platelets. Characterization of the alloantibodies showed that the low levels of MC significantly influenced the isotype of the antidonor IgG; the presence of 1 MC/μL was associated with induction of noncomplement fixing IgG1 antidonor antibodies, whereas platelet transfusions, devoid of MC (<0.05/μL), were responsible for complement-fixing IgG2a production. When magnetically sorted defined subpopulations of MC were added to the SCID platelets, major histocompatability complex (MHC) class II positive populations, particularly B cells, were found to be primarily responsible for the reduced SCID mouse platelet immunity. The presence of low numbers of MC within the platelets was also associated with an age-dependent reduction in platelet immunogenicity; this relationship however, was not observed with SCID mouse platelets devoid of MC. The results suggest that a residual number of MHC class II positive B cells within allogeneic platelets are required for maximally reducing alloimmunization.

scholarly journals Chemical Hypoxia Brings to Light Altered Autocrine Sphingosine-1-Phosphate Signalling in Rheumatoid Arthritis Synovial Fibroblasts

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Chenqi Zhao ◽  
Uriel Moreno-Nieves ◽  
John A. Di Battista ◽  
Maria J. Fernandes ◽  
Mohamed Touaibia ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Synovial Cell ◽  
Synovial Fibroblasts ◽  
Sphingolipid Metabolism ◽  
Normal Fibroblast ◽  
Chemokine Production ◽  
Chemical Hypoxia ◽  
Sphingosine 1 Phosphate ◽  
S1p Lyase ◽  
Fibroblast Like Synoviocytes

Emerging evidence suggests a role for sphingosine-1-phosphate (S1P) in various aspects of rheumatoid arthritis (RA) pathogenesis. In this study we compared the effect of chemical hypoxia induced by cobalt chloride (CoCl2) on the expression of S1P metabolic enzymes and cytokine/chemokine secretion in normal fibroblast-like synoviocytes (FLS) and RAFLS. RAFLS incubated with CoCl2, but not S1P, produced less IL-8 and MCP-1 than normal FLS. Furthermore, incubation with the S1P2and S1P3receptor antagonists, JTE-013 and CAY10444, reduced CoCl2-mediated chemokine production in normal FLS but not in RAFLS. RAFLS showed lower levels of intracellular S1P and enhanced mRNA expression of S1P phosphatase 1 (SGPP1) and S1P lyase (SPL), the enzymes that are involved in intracellular S1P degradation, when compared to normal FLS. Incubation with CoCl2decreased SGPP1 mRNA and protein and SPL mRNA as well. Inhibition of SPL enhanced CoCl2-mediated cytokine/chemokine release and restored autocrine activation of S1P2and S1P3receptors in RAFLS. The results suggest that the sphingolipid pathway regulating the intracellular levels of S1P is dysregulated in RAFLS and has a significant impact on cell autocrine activation by S1P. Altered sphingolipid metabolism in FLS from patients with advanced RA raises the issue of synovial cell burnout due to chronic inflammation.

scholarly journals A Bioassay Using a Pentadecanal Derivative to Measure S1P Lyase Activity

2021 ◽  
Vol 22 (3) ◽  
pp. 1438
Author(s):  
Kyong-Oh Shin ◽  
Maftuna Shamshiddinova ◽  
Jung-No Lee ◽  
Kwang-Sik Lee ◽  
Yong-Moon Lee
Keyword(s):  
Embryonal Carcinoma Cell ◽  
Carcinoma Cell Lines ◽  
Highly Sensitive ◽  
Lyase Activity ◽  
Sphingosine 1 Phosphate ◽  
Km Value ◽  
S1p Lyase ◽  
Higher Sensitivity

Sphingosine-1-phosphate (S1P) is a unique lipid ligand binding to S1P receptors to transduce various cell survival or proliferation signals via small G proteins. S1P lyase (S1PL) is the specific enzyme that degrades S1P to phosphoethanolamine and (2E)-hexadecenal and therefore regulates S1P levels. S1PL also degrades dihydrosphingosine-1-phosphate (Sa1P), with a higher affinity to produce hexadecanal. Here, we developed a newly designed assay using a C17-Sa1P substrate that degrades into pentadecanal and phosphoethanolamine. For higher sensitivity in pentadecanal analysis, we developed a quantitative protocol as well as a 5,5-dimethyl cyclohexanedione (5,5-dimethyl CHD) derivatization method. The derivatization conditions were optimized for the reaction time, temperature, and concentrations of the 5,5-dimethyl CHD reagent, acetic acid, and ammonium acetate. The S1PL reaction in the cell lysate after spiking 20 µM of C17-Sa1P for 20 min was linear to the total protein concentrations of 50 µg. The S1PL levels (4 pmol/mg/min) were readily detected in this HPLC with fluorescence detection (λex = 366 nm, λem = 455 nm). The S1PL-catalyzed reaction was linear over 30 min and yielded a Km value of 2.68 μM for C17-Sa1P. This new method was validated to measure the S1PL activity of mouse embryonal carcinoma cell lines of the standard cell (F9-0), S1PL knockdown cells (F9-2), and S1PL-overexpressed cells (F9-4). Furthermore, we treated F9-4 cells with different S1PL inhibitors such as FTY720, 4-deoxypyridoxine (DOP), and the deletion of pyridoxal-5-phosphate (P5P), an essential cofactor for S1PL activity, and observed a significant decrease in pentadecanal relative to the untreated cells. In conclusion, we developed a highly sensitive S1PL assay using a C17-Sa1P substrate for pentadecanal quantification for application in the characterization of S1PL activity in vitro.

scholarly journals Drosophila DNA/RNA methyltransferase contributes to robust host defense in aging animals by regulating sphingolipid metabolism

2018 ◽  
Vol 221 (22) ◽  
pp. jeb187989 ◽  
Author(s):  
Varada Abhyankar ◽  
Bhagyashree Kaduskar ◽  
Siddhesh S. Kamat ◽  
Deepti Deobagkar ◽  
Girish S. Ratnaparkhi
Keyword(s):  
Host Defense ◽  
Sphingolipid Metabolism
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