Identification of a PRDM1-regulated T cell network to regulate T cell driving plaque inflammation in human and mouse atherosclerosis

 

T cells have a prominent role in the pathogenesis of atherosclerosis, although their exact function remains elusive. Here, we pursued a network-driven approach to identify T cell-associated gene programs driving the transition from low- to high-risk human plaques.

In this study 43 human carotid arterial plaques were collected and stratified based on absence (low-risk) or presence (high-risk) of intraplaque haemorrhage (IPH). Lesion RNA was subjected to microarray gene expression analysis and analysed by Weighted Gene Co-expression Network Analysis (WGCNA). We identified a co-expressed gene cluster displaying a strong T cell signalling signature in high- versus low-risk plaque, which was tightly connected to subnetworks of angiogenesis and interferon-signalling. WGCNA-based Bayesian network inference, cell-type deconvolution and single-cell gene expression revealed that this T cell-associated gene program was likely linked to effector-memory cytotoxic CD8+ T cells, underpinning the central role of T cells in plaque destabilization. Gene regulatory analysis identified cytotoxic T cell-related transcription factors, like PRDM1, regulating this plaque T cell gene program. Moreover, we demonstrated in LDL receptor knockout mice with T cell-specific Prdm1 deficiency, that lack of Prdm1 in T cells resulted in larger, more advanced plaques.

In conclusion, our study reveals a PRDM1-regulated T cell footprint in high- versus low-risk human atherosclerotic lesions and murine atherosclerotic plaque development, thereby identifying this network as a potential target for intervention in adverse T cell responses.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): The European Research Area Network on Cardiovascular Diseases (ERA-CVD and Dutch Heart Foundation)

Toxicity and physicochemical parameters of composts including distinct residues from agribusiness and slaughterhouse sludge

Composting is useful for treatment of residues from agribusiness, but the potential toxicity of the final compost should be evaluated before its agricultural destination. The objective of this study was to evaluate the physicochemical characteristics and the toxicity of agribusiness residues using onion seeds as bioindicators. All tested treatments were composed by sludge from a swine slaughterhouse and sawdust. Besides the control, which included no additional materials, the other treatments included aviary bedding, rice husk and residue from tobacco industries as structuring materials. After 120 days of composting, for all treatments, the temperature inside the composting piles approached the environmental temperature, the physicochemical parameters indicated that the composts were stabilized and, except for the treatment including tobacco residues, that could be used for agriculture without impairing plant germination. Although the treatments including tobacco residues and rice husk showed evidence of cytotoxicity and genotoxicity at the beginning of the composting period, that was not observed for the treatment including aviary bedding. Such potential toxicity was not observed at the end of composting for any of the tested treatments.

GESTÃO DA QUALIDADE NO AMBIENTE AGRÍCOLA: UM ESTUDO DE CASO DA APLICAÇÃO DO GERENCIAMENTO DA ROTINA NO SETOR SUCROENERGÉTICO

O setor sucroenergético busca maiores produtividades que justifiquem a produção de açúcar, etanol e bioenergia aos seus investidores. A manutenção agrícola necessita entregar um alto nível de qualidade em seu serviço de forma a garantir que os equipamentos trabalhem em sua máxima disponibilidade para alcançar tais produtividades. A utilização de novos métodos de gestão, como a gestão da qualidade, são formas de buscar tais resultados. O estudo de caso se desenvolveu a partir da aplicação de ferramentas de gestão da qualidade na área de manutenção agrícola de uma usina no setor sucroenergético. Entre os períodos pré e pós aplicação da gestão da rotina observou-se um aumento de 22,79 ton.máq-1.dia-1 na produtividade das colhedoras de cana-de-açúcar. Os resultados demonstraram que, embora necessite de mais tempo para expressar um maior potencial de melhoria no processo, a metodologia de gestão de rotina trouxe benefícios positivos à área de manutenção agrícola.

Avaliação in vitro de espermatozoides da cauda do epidídimo de caprinos, resfriado a 4 ºc em diferentes diluidores

A colheita de espermatozóides da cauda do epidídimo (CES) é uma opção viável de preservação de material genético de espécies ameaçadas de extinção, bem como para uso em reprodução assistida. Este trabalho teve como objetivo verificar a eficiência de quatro diferentes diluidores sobre os espermatozóides da cauda do epidídimo de caprinos, resfriado a 4 ºC. Os espermatozoides epididimários foram recuperados da cauda de seis pares de epidídimo. As amostras de cada par foram misturadas e subdivididas em quatro alíquotas que foram diluídas na água de coco-gema (CW-EY), solução fisiológica glicosada 0,5 %-gema (PSG), leite desnatado UHT (ME) e leite desnatado UHT-gema (ME-EY). As amostras foram resfriadas a 4 °C por 2, 12, 24 e 48 horas. Após o armazenamento, em cada período, o CES foi avaliado através do teste de termoresistência quanto à motilidade, vigor espermático e alterações morfológicas total. A taxa de degradação da motilidade foi calculada no final de cada período. A viabilidade espermática diminuiu com o tempo de refrigeração nos quatro diluidores. Os CES diluídos na CW-EY apresentaram maiores valores para vigor e motilidade, embora estes parâmetros não deferissem daqueles mantidos no PSG por até 48 horas, exceto para vigor espermático. Entretanto, os diluidores PSG e ME ocasionaram maiores danos morfológicos aos CES a partir de 12 e 48 horas, respectivamente. Os diluidores ME e ME-EY proporcionaram à célula espermática menor estabilidade durante 48 h de conservação. Concluiu-se que o CW-EY foi o mais eficiente em manter a viabilidade dos CES a 4 ºC.

The anti-IRBP IgG1 and IgG2a response does not correlate with susceptibility to experimental autoimmune uveitis

Susceptibility to experimental autoimmune uveitis (EAU) in inbred mice has been associated with a dominant Th1 response. Elevated anti-inter-photoreceptor retinoid-binding protein (anti-IRBP) IgG2a/IgG1 antibody ratios have been implicated as candidate markers to predict disease severity. In the present study, both the anti-IRBP antibody isotype and severity of EAU phenotypes were examined in 4 non-isogenic genetically selected mouse lines to determine if they can be used as general markers of disease. Mice between 8 and 12 weeks old selected for high (H(III)) or low (L(III)) antibody response and for maximum (AIR(MAX)) or minimum (AIR(MIN)) acute inflammatory reaction (AIR) were immunized with IRBP. Each experiment was performed with at least 5 mice per group. EAU was evaluated by histopathology 21 days after immunization and the minimal criterion was inflammatory cell infiltration of the ciliary body, choroid and retina. Serum IgG1- and IgG2a-specific antibodies were determined by ELISA. EAU was graded by histological examination of the enucleated eyes. The incidence of EAU was lower in AIR(MIN) mice whereas in the other strains approximately 40% of the animals developed the disease. Low responder animals did not produce anti-IRBP IgG2a antibodies or interferon-gamma. No correlation was observed between susceptibility to EAU and anti-IRBP isotype profiles. Susceptibility to EAU is related to the intrinsic capacity to mount higher inflammatory reactions and increased production of anti-IRBP IgG2a isotype is not necessarily a marker of this immunologic profile.

Fas-FasL interaction modulates nitric oxide production in Trypanosoma cruzi-infected mice

During acute Trypanosoma cruzi infection in mice, many leucocytes undergo apoptosis. Although apoptosis has been ascribed to increased levels of nitric oxide (NO) and Fas-FasL interaction, the importance of this phenomenon in modulating the host response against T. cruzi is unknown. Herein, the role of NO- and Fas-FasL-induced apoptosis in modulating the immune response to T. cruzi was evaluated using mice deficient in Fas expression (MRL/MpJ-Fas lpr) and inducible nitric oxide synthase (iNOS) knockout mice (iNOS-/-). The results showed that besides decreasing apoptosis induction after infection, impairment of the Fas-FasL interaction resulted in decreased NO production, as a consequence of enhanced T helper 2 (Th2) cytokine production. Differently, blockage of NO-induced apoptosis resulted in uncontrolled cytokine production, rather than a biased Th2 cytokine pattern. Together, these results suggested that Fas and FasL-induced apoptosis could be implied in modulation of the immune response against T. cruzi by interfering with cytokine and NO production during the acute phase of the infection.

Trypanosoma cruzi-infected cardiomyocytes produce chemokines and cytokines that trigger potent nitric oxide-dependent trypanocidal activity

BACKGROUND

The pathogenesis of myocarditis that occurs in Trypanosoma cruzi-infected mice is still poorly understood. Therefore, it is important to know the mediators that trigger leukocyte migration to the heart as well as the cellular source of these possible mediators. In this study, we investigated (1) NO synthase (NOS) induction, (2) NO synthesis, (3) trypanocidal activity, and (4) chemokine and cytokine mRNA expression by isolated cardiomyocytes infected with T cruzi.

METHODS AND RESULTS

Mouse cardiomyocytes were isolated, infected with T cruzi, and evaluated for induction of inducible NOS (iNOS), nitrite production, trypanocidal activity, and cytokine and chemokine mRNA expression. We found that T cruzi-infected murine embryonic cardiomyocytes produced nitrite and expressed mRNAs for the chemokines chemokine growth-related oncogene, monokine induced by interferon-gamma, macrophage inflammatory protein-2, interferon-gamma-inducible protein, RANTES, and monocyte chemotactic protein, for iNOS, and for the cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta. Separate addition of IL-1beta, interferon-gamma, TNF-alpha or monocyte chemotactic protein, macrophage inflammatory protein-2, and interferon-gamma-inducible protein, to cultured cardiomyocytes resulted in NO production but low trypanocidal activity. However, simultaneous addition of IL-1beta, interferon-gamma, and TNF-alpha or the chemokines to cultures resulted in the induction of iNOS, high levels of nitrite, and a marked trypanocidal activity. The iNOS/L-arginine pathway mediated the latter activity, inasmuch as it was inhibited by treatment with N:(G)-monomethyl-L-arginine.

CONCLUSIONS

These results indicate that iNOS activation and the proinflammatory cytokines and chemokines produced by cardiomyocytes are likely to control parasite growth and cell influx, thus contributing to the pathogenesis of chagasic cardiomyopathy seen in T cruzi-infected mice.

Free DNA induces modification on the protein synthesis profile of human peripheral blood mononuclear cells of healthy donors

Understanding how free DNA might act as a signal between cells is important for knowing how DNA orchestrates immune responses and for optimizing the therapeutic of cancer, infection and immunologic diseases. This communication demonstrates that DNAs from different origins (bacteria, T. cruzi, HeLa cells) and synthetic oligonucleotide containing an unmethylated CpG motif are capable of inducing alterations in the protein profile of normal human leukocytes. As far as we know there have been no similar studies regarding the comparative effects of different free DNAs on early protein synthesis of human peripheral blood mononuclear cells.

Detection of DNA in the plasma of septic patients

Small amounts of plasma-free DNA have been observed both in healthy individuals and in patients with various diseases such as systemic lupus erythematosus, rheumatoid arthritis, viral hepatitis, and cancer. This communication demonstrates that septic patients also release DNA in plasma. After DNA extraction from plasma, exon 1 of the K-ras gene was amplified by PCR and products were analyzed by dot-blot hybridization. Plasmas from polytraumatic patients and control healthy individuals were used for comparisons with septic patients. Our results show that septic patients present DNA in their plasma. As far as we know, this is the first evidence of circulating DNA in septic patients.

Gamma interferon modulates CD95 (Fas) and CD95 ligand (Fas-L) expression and nitric oxide-induced apoptosis during the acute phase of Trypanosoma cruzi infection: a possible role in immune response control

We have previously shown that splenocytes from mice acutely infected with Trypanosoma cruzi exhibit high levels of nitric oxide (NO)-mediated apoptosis. In the present study, we used the gamma interferon (IFN-gamma)-knockout (IFN-gamma(-/-)) mice to investigate the role of IFN-gamma in modulating apoptosis induction and host protection during T. cruzi infection in mice. IFN-gamma(-/-) mice were highly susceptible to infection and exhibited significant reduction of NO production and apoptosis levels in splenocytes but normal lymphoproliferative response compared to the infected wild-type (WT) mice. Furthermore, IFN-gamma modulates an enhancement of Fas and Fas-L expression after infection, since the infected IFN-gamma(-/-) mice showed significantly lower levels of Fas and Fas-L expression. The addition of recombinant murine IFN-gamma to spleen cells cultures from infected IFN-gamma(-/-) mice increased apoptosis levels, Fas expression, and NO production. In the presence of IFN-gamma and absence of NO, although Fas expression was maintained, apoptosis levels were significantly reduced but still higher than those found in splenocytes from uninfected mice, suggesting that Fas-Fas-L interaction could also play a role in apoptosis induction in T. cruzi-infected mice. Moreover, in vivo, the treatment of infected WT mice with the inducible nitric oxide synthase inhibitor aminoguanidine also led to decreased NO and apoptosis levels but not Fas expression, suggesting that IFN-gamma modulates apoptosis induction by two independent and distinct mechanisms: induction of NO production and of Fas and Fas-L expression. We suggest that besides being of crucial importance in mediating resistance to experimental T. cruzi infection, IFN-gamma could participate in the immune response control through apoptosis modulation.

The adjuvant effect of jacalin on the mouse humoral immune response to trinitrophenyl and Trypanosoma cruzi

We have evaluated the adjuvant action of jacalin, a lectin obtained from seeds of Artocarpus integrifolia, on humoral immune response against the trinitrophenyl (TNP) hapten when conjugated to it and to Trypanosoma cruzi. The protective effect of parasite-specific antibodies generated in mice immunized with epimastigote forms of T. cruzi plus jacalin was also evaluated by determining the parasitemia levels of animals after infection with 1000 trypomastigote forms. Immunization of mice with trinitrophenylated jacalin (TNP-JAC) in saline resulted in an antibody response to the TNP hapten that was eight and 16 times higher than that found in mice immunized with TNP-human gamma globulin (TNP-HGG) or TNP-bovine serum albumin (TNP-BSA), respectively. In addition, immunization with either a lysate or viable epimastigote forms of T. cruzi in the presence of jacalin resulted in a marked increase in the levels of anti-T. cruzi antibodies. The protective action of antibodies against acute infection by T. cruzi was evident when mice were immunized with 1.0 x 10(5) epimastigotes plus jacalin. These animals had a significantly lower parasitemia than those immunized with epimastigotes alone. In contrast, mice immunized with 1.0 x 10(6) epimastigotes developed very low levels of parasitemia, regardless of the presence of jacalin. These data suggest that jacalin is a potent adjuvant in the humoral response to TNP and T. cruzi, and that the protective action of the T. cruzi-specific antibodies depends on the number of parasites used in the immunization protocol.

Expression of heat shock protein 70 in leukocytes of patients with sepsis

The heat shock proteins are known to protect cells against diverse injuries such as cytotoxicity by TNFalpha acting mainly as chaperones for denatured proteins. Lipopolysaccharide stimulates the production and the release of numerous endogenous mediators of sepsis: tumor necrosis factor alpha, interleukin-1, and interleukin-6 that induce fever production. Moreover, temperature at 40 degrees C is sufficient to induce heat shock and attenuate both TNFalpha and IL-1 expression. We demonstrate a distinct profile in gene expression of HSP 70 family in leukocytes obtained from different phases of septic patients. Our findings strongly suggest that HSP 70 may play a role in the outcome of septic shock patients.

Nitric oxide-induced apoptotic cell death in the acute phase of Trypanosoma cruzi infection in mice

Production of gamma-interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) in Trypanosoma cruzi-infected mice results in the activation of inducible nitric oxide synthase (iNOS) and in elevated nitric oxide (NO) synthesis, which is important for the macrophage trypanocidal activity. However, NO has been shown to be involved in suppression of host immunity. In the present investigation, we studied the role of NO in inducing apoptosis in cells from BALB/c mice acutely infected by T. cruzi. Splenocytes from infected mice had a reduced cell viability and elevated levels of spontaneous apoptosis after 48 h in culture. Inhibition of NO production by the addition of the L-arginine analog NG-monomethyl-L-arginine (L-NMMA), or of monoclonal antibodies (mAbs) to IFN-gamma or TNF-alpha spleen cells, partially restored cell viability and caused a decrease in the levels of apoptosis in splenocytes from infected animals. Spleen cells from T. cruzi-infected mice had an apoptosis-specific pattern of internucleosomal DNA fragmentation which was most marked at the ninth day after infection when the plasma NO levels and parasitemia were increased. Treatment of infected mice with L-NMMA, anti-TNF-alpha, or anti-IFN-gamma mAbs caused reduction of both NO production and the amount of apoptotic cells, suggesting that NO plays a direct role in the induction of apoptosis in vivo. Taken together, these data support the hypothesis that, as well as modulating immunosuppression, NO produced by IFN-gamma and TNF-alpha activated macrophages plays a role in apoptosis induction during the acute phase of experimental T. cruzi infection.

A morphometric study of maternal smoking on apoptosis in the syncytiotrophoblast

OBJECTIVES

To study syncytiotrophoblast apoptosis in the placenta of smoking and non-smoking pregnant women.

METHODS

Twelve neonates, pregnancies and placentas were available for study. Eight mothers smoked during pregnancy and the remaining four were non-smokers used as control subjects. The main outcome measure was the apoptotic syncytiotrophoblast index for each group. Apoptosis was detected by immunohistochemistry using the TUNEL method and quantitatively measured using a Merz grid. The apoptotic syncytiotrophoblast index was calculated as the ratio of mean apoptotic labeling to percent terminal villus area using high-power field microscopy.

RESULTS

Significant differences in apoptotic syncytiotrophoblast index were observed between the control group (15.06+/-3.72) and the smoker group (1.66+/-1.74) (P < 0.0001, Mann-Whitney test), but no differences were detected in clinical or morphometric data between groups.

CONCLUSIONS

The human placental syncytiotrophoblast undergoes apoptosis and this process is associated with inhibition of apoptosis by the smoking habit. The same way as the presence of trophoblast apoptosis is associated with modifications of the maternal-fetal exchange, the inhibitory effect of the smoking habit on syncytiotrophoblast could be responsible for the poor prognosis of pregnancy in the presence of maternal smoking.

The role of IL-12 in experimental Trypanosoma cruzi infection

Host resistance to Trypanosoma cruzi infection is dependent on both natural and acquired immune responses. During the early acute phase of infection in mice, natural killer (NK) cell-derived IFN-gamma is involved in controlling intracellular parasite replication, mainly through the induction of nitric oxide biosynthesis by activated macrophages. We have shown that IL-12, a powerful inducer of IFN-gamma production by NK cells, is synthesized soon after trypomastigote-macrophage interaction. The role of IL-12 in the control of T. cruzi infection in vivo was determined by treating infected mice with anti-IL-12 monoclonal antibody (mAb) and analyzing both parasitemia and mortality during the acute phase of infection. The anti-IL-12 mAb-treated mice had higher levels of parasitemia and mortality compared to control mice. Also, treatment of infected mice with mAb specific for IFN-gamma or TNF-alpha inhibited the protective effect of exogenous IL-12. On the other hand, TGF-beta and IL-10 produced by infected macrophages inhibited the induction and effects of IL-12. Therefore, while IL-12, TNF-alpha and IFN-gamma correlate with resistance to T. cruzi infection, TGF-beta and IL-10 promote susceptibility. These results provide support for a role of innate immunity in the control of T. cruzi infection. In addition to its protective role, IL-12 may also be involved in the modulation of T. cruzi-induced myocarditis, since treatment of infected mice with IL-12 or anti-IL-12 mAb leads to an enhanced or decreased inflammatory infiltrate in the heart, respectively. Understanding the role of the cytokines produced during the acute phase of T. cruzi infection and their involvement in protection and pathogenesis would be essential to devise new vaccines or therapies.

Induction of cell-mediated immunity during early stages of infection with intracellular protozoa

Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI) maintained by Th1 lymphocytes and IFN-gamma. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serve as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host). Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.

Interleukin-12 mediates resistance to Trypanosoma cruzi in mice and is produced by murine macrophages in response to live trypomastigotes

Host resistance to infection by Trypanosoma cruzi is dependent on both natural and acquired immune responses. During the first week of infection in mice, NK cell-derived gamma interferon (IFN-gamma) is involved in controlling intracellular parasite replication, mainly through the induction of NO biosynthesis by activated macrophages. Interleukin-12 (IL-12) has been shown to be a powerful cytokine in inducing IFN-gamma synthesis by NK cells, as well as in mediating resistance to different intracellular protozoa. We have therefore studied the ability of T. cruzi to elicit IL-12 synthesis by macrophages and the role of this cytokine in controlling parasite replication during acute infection in mice. Our results show that macrophages cultured in the presence of live trypomastigote forms (but not epimastigotes) release IL-12 that can induce IFN-gamma production by normal spleen cells. IL-12 was detected in as little as 12 h after the addition of the trypomastigotes, and the level of IL-12 peaked at 48 h after the initial macrophage-parasite incubation. The addition of anti-IL-12 monoclonal antibody to macrophage-trypomastigote supernatants dose-dependently inhibited IFN-gamma production by naive splenocytes. Finally, the in vivo role of IL-12 in resistance to infection by T. cruzi was analyzed. Mice treated with anti-IL-12 monoclonal antibody had significantly increased parasitemia and mortality in comparison with those of control infected mice treated with control antibody. Together, these results suggest that macrophage-derived IL-12 plays a major role in controlling the parasitemia in T. cruzi-infected mice and that the animal's resistance during the acute phase of infection may, at least in part, be a consequence of postinfection levels of IL-12.