Lipid-loaded tumor-associated macrophages sustain tumor growth and invasiveness in prostate cancer.

Tumor-associated macrophages (TAMs) are correlated with the progression of prostatic adenocarcinoma (PCa). The mechanistic basis of this correlation and therapeutic strategies to target TAMs in PCa remain poorly defined. Here, single-cell RNA sequencing was used to profile the transcriptional landscape of TAMs in human PCa, leading to identification of a subset of macrophages characterized by dysregulation in transcriptional pathways associated with lipid metabolism. This subset of TAMs correlates positively with PCa progression and shorter disease-free survival and is characterized by an accumulation of lipids that is dependent on Marco. Mechanistically, cancer cell-derived IL-1ß enhances Marco expression on macrophages, and reciprocally, cancer cell migration is promoted by CCL6 released by lipid-loaded TAMs. Moreover, administration of a high-fat diet to tumor-bearing mice raises the abundance of lipid-loaded TAMs. Finally, targeting lipid accumulation by Marco blockade hinders tumor growth and invasiveness and improves the efficacy of chemotherapy in models of PCa, pointing to combinatorial strategies that may influence patient outcomes.

Inhibiting glycolysis rescues memory impairment in an intellectual disability Gdi1-null mouse.

OBJECTIVES: GDI1 gene encodes for αGDI, a protein controlling the cycling of small GTPases, reputed to orchestrate vesicle trafficking. Mutations in human GDI1 are responsible for intellectual disability (ID). In mice with ablated Gdi1, a model of ID, impaired working and associative short-term memory was recorded. This cognitive phenotype worsens if the deletion of αGDI expression is restricted to neurons. However, whether astrocytes, key homeostasis providing neuroglial cells, supporting neurons via aerobic glycolysis, contribute to this cognitive impairment is unclear. METHODS: We carried out proteomic analysis and monitored [18F]-fluoro-2-deoxy-d-glucose uptake into brain slices of Gdi1 knockout and wild type control mice. d-Glucose utilization at single astrocyte level was measured by the Förster Resonance Energy Transfer (FRET)-based measurements of cytosolic cyclic AMP, d-glucose and L-lactate, evoked by agonists selective for noradrenaline and L-lactate receptors. To test the role of astrocyte-resident processes in disease phenotype, we generated an inducible Gdi1 knockout mouse carrying the Gdi1 deletion only in adult astrocytes and conducted behavioural tests. RESULTS: Proteomic analysis revealed significant changes in astrocyte-resident glycolytic enzymes. Imaging [18F]-fluoro-2-deoxy-d-glucose revealed an increased d-glucose uptake in Gdi1 knockout tissue versus wild type control mice, consistent with the facilitated d-glucose uptake determined by FRET measurements. In mice with Gdi1 deletion restricted to astrocytes, a selective and significant impairment in working memory was recorded, which was rescued by inhibiting glycolysis by 2-deoxy-d-glucose injection. CONCLUSIONS: These results reveal a new astrocyte-based mechanism in neurodevelopmental disorders and open a novel therapeutic opportunity of targeting aerobic glycolysis, advocating a change in clinical practice.

Re-education of Tumor-Associated Macrophages by CXCR2 Blockade Drives Senescence and Tumor Inhibition in Advanced Prostate Cancer.

Tumor-associated macrophages (TAMs) represent a major component of the tumor microenvironment supporting tumorigenesis. TAMs re-education has been proposed as a strategy to promote tumor inhibition. However, whether this approach may work in prostate cancer is unknown. Here we find that Pten-null prostate tumors are strongly infiltrated by TAMs expressing C-X-C chemokine receptor type 2 (CXCR2), and activation of this receptor through CXCL2 polarizes macrophages toward an anti-inflammatory phenotype. Notably, pharmacological blockade of CXCR2 receptor by a selective antagonist promoted the re-education of TAMs toward a pro-inflammatory phenotype. Strikingly, CXCR2 knockout monocytes infused in Ptenpc-/-; Trp53pc-/- mice differentiated in tumor necrosis factor alpha (TNF-α)-releasing pro-inflammatory macrophages, leading to senescence and tumor inhibition. Mechanistically, PTEN-deficient tumor cells are vulnerable to TNF-α-induced senescence, because of an increase of TNFR1. Our results identify TAMs as targets in prostate cancer and describe a therapeutic strategy based on CXCR2 blockade to harness anti-tumorigenic potential of macrophages against this disease.

Interleukin 21 (IL-21)/microRNA-29 (miR-29) axis is associated with natural resistance to HIV-1 infection.

BACKGROUND: Interleukin-21 (IL-21) modulates HIV-1 infection through the elicitation of different antiviral mechanisms, including Th17 lineage commitment and induction of microRNA (miR)-29, a miRNA endowed with anti-HIV activity. As miR-29 expression is significantly increased in HIV-1-exposed seronegative individuals (HESN), we investigated the role of miR-29/IL21 axis in the natural control of HIV-1 infection. METHODS: Peripheral blood mononuclear cells (PBMCs) isolated from 15 Italian sexually exposed HESN and 15 HIV-unexposed healthy controls were in-vitro infected with an R5-tropic HIV-1Ba-L strain. Seven days post HIV-1 infection we evaluated: 1) p24 production (ELISA); 2) CD4/IL-21 and CD4/IL-17 T lymphocytes (FACS); 3) IL-17 concentration in supernatants (ELISA); and 4) IL-6, IL-17, IL-21, and miR-29a,b,c expression by CD4 T lymphocytes as well as perforin and granzyme by peripheral blood mononuclear cells (qPCR). The same analyses were performed on the 15 HIV-positive partners. RESULTS: At baseline IL-6 expression alone was increased in HESN compared to healthy controls. Seven days after in-vitro HIV-1 infection, nevertheless, differences emerged. Thus, CD4/IL21 and CD4/IL17 T lymphocytes, as well as IL-21 and IL-17 expression and production were significantly augmented in HESN compared to healthy controls. Interestingly, IL-21 upregulation correlated with a significantly increased expression of miR-29a,b,c and a reduced susceptibility to in-vitro HIV-1 infection in HESN alone. No differences were observed in perforin and granzyme expression. CONCLUSION: The IL-21/miR-29 axis is upregulated by HIV-1 infection in HESN suggesting its involvement in the natural resistance to HIV-1 infection in HESN. Approaches that exogenously increase IL-21 production or prompt preexisting cellular IL-21 reservoir could confine the magnitude of the initial HIV-1 infection.

Evaluation of adhesion molecules and immune parameters in HIV-infected patients treated with an atazanavir/ritonavir- compared with a lopinavir/ritonavir-based regimen.

Objectives: To evaluate changes in pro-atherosclerotic biomarkers and endothelial function in patients initiating two different PI-based regimens as part of ART. Design: Prospective randomized 24 week study. Treatment-naive HIV-infected patients with CD4+ T cell count >250 cells/mm3 started PI-based regimens including atazanavir/ritonavir (Group A) or lopinavir/ritonavir (Group B) and were followed up in an observational follow-up study until week 96. Methods: The expression of immune activation and adhesion molecules on CD4+ and CD8+ cells and plasma cytokine levels were assessed at weeks 0, 4, 12, 24, 48, 72 and 96. Flow-mediated dilation (FMD), pulse-wave velocity (PWV) and intima-media thickness (IMT) were measured at weeks 0 and 24. Median changes within (signed rank test) and between (Wilcoxon test) arms were calculated. Results: Twenty-seven patients were enrolled, of whom 15 were treated with atazanavir/ritonavir and 12 with lopinavir/ritonavir. After 96 weeks of ART, CD25+/CD8+ T cells and plasma concentration of MCP-1/CCL-2 rose whereas CD44+/CD8+ T cells decreased significantly in both groups. Differences between treatments were noted for HLA-DRII+/CD8+, CD44+/CD4+ and CD11a+/CD4+, with significant increases in Group B versus Group A. No differences between groups regarding IMT, PWV and FMD were found at baseline and week 24. Conclusions: ART initiation with PI-based regimens led to a decrease in pro-atherosclerotic biomarkers at week 24, which then rebounded at week 96. Lopinavir/ritonavir treatment resulted in an unfavourable modulation of such markers compared with atazanavir/ritonavir treatment.

Humoral and cell-mediated immune responses after a booster dose of HBV vaccine in HIV-infected children, adolescents and young adults.

OBJECTIVE: HBV vaccine induces protective antibodies only in 23-56% of HIV-infected children. The aim of our study is to evaluate the immunologic effects of a booster dose of HBV vaccine in HIV-infected youth. DESIGN: 53 young HIV-infected patients in whom HBV vaccination did not elicit protective Ab titers were enrolled. All patients were on ART with optimal immunological and viral response. METHOD: All patients received a booster dose of HBV vaccine (HBVAXPRO 10 µg i.m.). HBV-specific Ab titer, viral load and CD4+ T cells were measured at baseline (T0), T1, T6 and T12 months. In a subgroup of 16 patients HBV-specific cell mediated immune responses were evaluated at baseline, at T1 and T6. RESULTS: The booster dose induced seroconversion in 51% of patients at T1, 57% at T6, and49% at T12; seroconversion rate was significantly correlated with CD4+T cells at T0 and to the CD4 nadir. The booster dose induced HBV-specific cell mediated immunity at T6 mainly in Responders (Rs): Effector Memory CD8+T cells, HBV-specific TNFα-, IFNγ-, granzyme secreting CD8+ T cells and IL2-secreting CD4+ T cells were significantly increased in Rs compared to T0. In Non Responders (NRs), HBV-specific IL2-secreting CD4+ T cells, Central and Effector Memory CD8+ T cells were the only parameters modified at T6. CONCLUSIONS: Seroconversion induced by a booster dose of vaccine correlates with the development of T cell immunological memory in HIV-infected patients who did not respond to the standard immunization. Alternate immunization schedules need to be considered in NRs.

The NLRP3 Inflammasome Is Upregulated in HIV-Infected Antiretroviral Therapy-Treated Individuals with Defective Immune Recovery.

Background: Inflammasome-mediated activation of caspase-1 regulates inflammatory responses and pyroptosis. We analyzed possible associations between inflammasome-related genes and immune reconstitution in HIV-infected antiretroviral therapy (ART)-treated patients. Methods: Cross-sectional, case-control study. HIV-infected patients on ART for ≥24 months with HIV-RNA<50 cp/mL for ≥12 months were enrolled and defined as immunological responders (IR) or non-responders (INR) if CD4 count was ≥500 or ≤350 cells/µL, respectively. Expression of inflammasome genes, caspases 1, 3, 4, 5 and γ-interferon-inducible protein 16 (IFI16) was measured in unstimulated and LPS- or aldrithiol-2-treated HIV-1BaL virions-stimulated peripheral blood mononuclear cells. Microbial translocation markers were evaluated. Results: Thirty-nine patients (22 IRs; 17 INRs) were enrolled. LPS-stimulated inflammasome genes were significantly upregulated in INRs. Whereas HIV-1BaL stimulation induced (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) expression in both IRs and INRs, NLRP3 and IL-18 expression was significantly increased in INRs compared to IRs. Significant higher caspase-1 expression was seen as well, whereas caspase 3, 4, and 5 expression was similar in both groups. No differences in microbial translocation markers (LPS and soluble CD14) were detected in the two groups. Conclusion: Upregulation of NLRP3 and caspase-1 is observed in INR patients. This could play a role in persistent immune activation that characterize INRs. Caspase-1 upregulation could induce CD4 T-cell loss via pyroptosis, contributing to unsatisfactory CD4 T-cells recovery.

Maraviroc Reduces Arterial Stiffness in PI-Treated HIV-infected Patients.

The Δ32-CCR5 deletion of the CCR5 receptor is protective toward coronary artery pathology and myocardial infarction. Maraviroc (MVC), a CCR5 antagonist, was recently introduced in the therapy of HIV infection; we evaluated whether this drug could modulate the atherosclerotic burden in aviremic PI-treated HIV-positive individuals who underwent MVC intensification. Thus, the effect of MVC on intima media thickness, arterial stiffness, metabolic parameters, pro-inflammatory cytokines, endothelial dysfunction, and microbial traslocation markers was analyzed in 6 aviremic PI-treated HIV-positive individuals and were compared to those obtained in 9 additional aviremic PI-treated subjects that were enrolled retrospectively from our outpatients cohort. MVC intensification resulted in a significant reduction in intima media thickness, pulse wave velocity and triglycerides compared to baseline. Notably, MVC was also associated with a significant reduction of IL-6, microbial translocation indexes, sICAM and sVCAM; these changes were maintained throughout the 6 months of MVC intensification. No significant modifications were observed in CD4 counts, HIV viral load, and cholesterolemia. Results herein support a role of CCR5 antagonists in reducing the cardiovascular risk in HIV-infection. The hampering of inflammation, microbial translocation and the improvement of endothelial function could justify the protective role of CCR5 antagonists on atherosclerotic burden.

Thiazolides Elicit Anti-Viral Innate Immunity and Reduce HIV Replication.

Nitazoxanide (Alinia(®), NTZ) and tizoxanide (TIZ), its active circulating metabolite, belong to a class of agents known as thiazolides (TZD) endowed with broad anti-infective activities. TIZ and RM-4848, the active metabolite of RM-5038, were shown to stimulate innate immunity in vitro. Because natural resistance to HIV-1 infection in HIV-exposed seronegative (HESN) individuals is suggested to be associated with strong innate immune responses, we verified whether TIZ and RM-4848 could reduce the in vitro infectiousness of HIV-1. Peripheral blood mononuclear cells (PBMCs) from 20 healthy donors were infected in vitro with HIV-1BaL in the presence/absence of TIZ or RM4848. HIV-1 p24 were measured at different timepoints. The immunomodulatory abilities of TZD were evaluated by the expression of type I IFN pathway genes and the production of cytokines and chemokines. TZD drastically inhibited in vitro HIV-1 replication (>87%). This was associated with the activation of innate immune responses and with the up-regulation of several interferon-stimulated genes (ISGs), including those involved in cholesterol pathway, particularly the cholesterol-25 hydroxylase (CH25H). TZD inhibition of HIV-1 replication in vitro could be due to their ability to stimulate potent and multifaceted antiviral immune responses. These data warrant the exploration of TZD as preventive/therapeutic agent in HIV infection.

RAB GTPases and RAB-interacting proteins and their role in the control of cognitive functions.

A RAS-related class of small monomeric G proteins, the RAB GTPases, is emerging as of key biological importance in compartment specific directional control of vesicles formation, transport and fusion. Thanks to human genetic observation and to the consequent dedicated biochemical work, substantial progress has been made on the understanding of the role played by RAB GTPases and their effector proteins on neuronal development and the shaping of cognitive functions. This review is highlighting these initial elements to broaden the current scope of research on developmental cognitive deficits and take the point of view of RAB GTPases control on membrane transport in neurons and astrocytes.