RESUMO
Glucagon-like peptide-1 receptor (GLP-1R) is a key regulator of glucose metabolism known to be expressed by pancreatic ß cells. We herein investigated the role of GLP-1R on T lymphocytes during immune response. Our data showed that a subset of T lymphocytes expresses GLP-1R, which is upregulated during alloimmune response, similarly to PD-1. When mice received islet or cardiac allotransplantation, an expansion of GLP-1Rpos T cells occurred in the spleen and was found to infiltrate the graft. Additional single-cell RNA sequencing (scRNA-seq) analysis conducted on GLP-1Rpos and GLP-1Rneg CD3+ T cells unveiled the existence of molecular and functional dissimilarities between both subpopulations, as the GLP-1Rpos are mainly composed of exhausted CD8 T cells. GLP-1R acts as a T cell-negative costimulatory molecule, and GLP-1R signaling prolongs allograft survival, mitigates alloimmune response, and reduces T lymphocyte graft infiltration. Notably, GLP-1R antagonism triggered anti-tumor immunity when tested in a preclinical mouse model of colorectal cancer.
Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1 , Transplante das Ilhotas Pancreáticas , Camundongos Endogâmicos C57BL , Animais , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Camundongos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Masculino , Transplante de Coração , Camundongos Endogâmicos BALB C , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Sobrevivência de Enxerto/imunologiaRESUMO
Pancreatic beta cells replenishment is considered the next therapeutic option for type 1 diabetes; while stimulating endogenous beta cells proliferation is the "holy grail" for those patients with exhausted beta cell mass. Here we are demonstrating that the pro-apoptotic receptor TMEM219 is expressed in fetal pancreas, in beta cell precursors and in in vitro embryonic-derived endocrine progenitors. TMEM219 signaling negatively regulates beta cells at early stages and induces Caspase 8-mediated cell death. Pharmacological blockade of TMEM219 further rescued beta cell precursor and proliferation markers, and decreased cell death, both in islets and in in vitro-derived endocrine progenitors, allowing for beta cell preservation. While addressing the upstream controlling TMEM219 expression, we determined the TMEM219 miRNet; indeed, one of those miRNAs, miR-129-2, is highly expressed in human islets, particularly in patients at risk or with established type 1 diabetes. miR-129-2 mimic downregulated TMEM219 expression in islets, in in vitro embryonic-derived endocrine progenitors and in highly proliferating insulinoma-derived cells. Moreover, miR-129-2 inhibitor induced a TMEM219 overexpression in insulinoma-derived cells, which restored cell proliferation and functional markers, thus acting as endogenous regulator of TMEM219 expression. The TMEM219 upstream regulator miR129-2 controls the fate of beta cell precursors and may unleash their regenerative potentials to replenish beta cells in type 1 diabetes.
Assuntos
Diabetes Mellitus Tipo 1 , Células Secretoras de Insulina , Insulinoma , MicroRNAs , Neoplasias Pancreáticas , Humanos , Proliferação de Células , Diabetes Mellitus Tipo 1/metabolismo , Células Secretoras de Insulina/metabolismo , Insulinoma/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Pancreáticas/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Apoptotic pathways have always been regarded as a key-player in preserving tissue and organ homeostasis. Excessive activation or resistance to activation of cell death signaling may indeed be responsible for several mechanisms of disease, including malignancy and chronic degenerative diseases. Therefore, targeting apoptotic factors gained more and more attention in the scientific community and novel strategies emerged aimed at selectively blocking or stimulating cell death signaling. This is also the case for the TMEM219 death receptor, which is activated by a circulating ligand, the Insulin-like growth factor binding protein 3 (IGFBP3) and induces a caspase-8-dependent apoptosis of the target cells. Interestingly, stimulation of the IGFBP3/TMEM219 axis exerts an anti-proliferative effect, while blockade of the TMEM219 deleterious signal protects TMEM219-expressing cells of the endocrine pancreas, lung, and intestine from damage and death. Here, we summarize the most updated reports on the role of the IGFBP3/TMEM219 apoptotic axis in disease conditions, including intestinal disorders and diabetes, and we describe the advancements in designing and testing novel TMEM219-based targeting approaches in emerging potential clinical applications.
Assuntos
Apoptose , Neoplasias , Humanos , Apoptose/fisiologia , Transdução de Sinais , Neoplasias/tratamento farmacológicoRESUMO
PURPOSE OF REVIEW: The purine nucleotide adenosine triphosphate (ATP) is released into extracellular spaces as extracellular ATP (eATP) as a consequence of cell injury or death and activates the purinergic receptors. Once released, eATP may facilitate T-lymphocyte activation and differentiation. The purpose of this review is to elucidate the role of ATP-mediated signaling in the immunological events related to type 1 diabetes (T1D). RECENT FINDINGS: T lymphocytes mediate immune response during the onset of T1D and promote pancreatic islet or whole pancreas rejection in transplantation. Recent data suggest a potential role for eATP in early steps of T1D onset and of allograft rejection. In different preclinical experimental models and clinical trials, several drugs targeting purinergic signaling have been employed to abrogate lymphocyte activation and differentiation, thus representing an achievable treatment to prevent/revert T1D or to induce long-term islet allograft function. SUMMARY: In preclinical and clinical settings, eATP-signaling inhibition induces immune tolerance in autoimmune disease and in allotransplantation. In this view, the purinergic system may represent a novel therapeutic target for auto- and allo-immunity.
Assuntos
Doenças Autoimunes , Diabetes Mellitus Tipo 1 , Humanos , Diabetes Mellitus Tipo 1/tratamento farmacológico , Doenças Autoimunes/tratamento farmacológico , Transplante Homólogo , Linfócitos T/metabolismo , Trifosfato de Adenosina/metabolismoRESUMO
Recent studies have shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may induce metabolic distress, leading to hyperglycemia in patients affected by coronavirus disease 19 (COVID-19). We investigated the potential indirect and direct effects of SARS-CoV-2 on human pancreatic islets in 10 patients who became hyperglycemic after COVID-19. Although there was no evidence of peripheral anti-islet autoimmunity, the serum of these patients displayed toxicity on human pancreatic islets, which could be abrogated by the use of anti-interleukin-1ß (IL-1ß), anti-IL-6, and anti-tumor necrosis factor α, cytokines known to be highly upregulated during COVID-19. Interestingly, the receptors of those aforementioned cytokines were highly expressed on human pancreatic islets. An increase in peripheral unmethylated INS DNA, a marker of cell death, was evident in several patients with COVID-19. Pathology of the pancreas from deceased hyperglycemic patients who had COVID-19 revealed mild lymphocytic infiltration of pancreatic islets and pancreatic lymph nodes. Moreover, SARS-CoV-2-specific viral RNA, along with the presence of several immature insulin granules or proinsulin, was detected in postmortem pancreatic tissues, suggestive of ß-cell-altered proinsulin processing, as well as ß-cell degeneration and hyperstimulation. These data demonstrate that SARS-CoV-2 may negatively affect human pancreatic islet function and survival by creating inflammatory conditions, possibly with a direct tropism, which may in turn lead to metabolic abnormalities observed in patients with COVID-19.
Assuntos
COVID-19 , Ilhotas Pancreáticas , COVID-19/complicações , Citocinas/metabolismo , Humanos , Hiperglicemia/virologia , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/virologia , Proinsulina/metabolismo , SARS-CoV-2RESUMO
Patients with type 1 diabetes (T1D) may develop severe outcomes during coronavirus disease 2019 (COVID-19), but their ability to generate an immune response against the SARS-CoV-2 mRNA vaccines remains to be established. We evaluated the safety, immunogenicity, and glycometabolic effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines in patients with T1D. A total of 375 patients (326 with T1D and 49 subjects without diabetes) who received two doses of the SARS-CoV-2 mRNA vaccines (mRNA-1273, BNT162b2) between March and April 2021 at ASST Fatebenefratelli Sacco were included in this monocentric observational study. Local and systemic adverse events were reported in both groups after SARS-CoV-2 mRNA vaccination, without statistical differences between them. While both patients with T1D and subjects without diabetes exhibited a parallel increase in anti-SARS-CoV-2 spike titers after vaccination, the majority of patients with T1D (70% and 78%, respectively) did not show any increase in the SARS-CoV-2-specific cytotoxic response compared with the robust increase observed in all subjects without diabetes. A reduced secretion of the T-cell-related cytokines interleukin-2 and tumor necrosis factor-α in vaccinated patients with T1D was also observed. No glycometabolic alterations were evident in patients with T1D using continuous glucose monitoring during follow-up. Administration of the SARS-CoV-2 mRNA vaccine is associated with an impaired cellular SARS-CoV-2-specific cytotoxic immune response in patients with T1D.
Assuntos
Vacina de mRNA-1273 contra 2019-nCoV , Vacina BNT162 , Diabetes Mellitus Tipo 1 , Vacina de mRNA-1273 contra 2019-nCoV/efeitos adversos , Vacina de mRNA-1273 contra 2019-nCoV/imunologia , Anticorpos Antivirais , Vacina BNT162/efeitos adversos , Vacina BNT162/imunologia , Glicemia , Automonitorização da Glicemia , COVID-19/prevenção & controle , Estudos de Coortes , Diabetes Mellitus Tipo 1/imunologia , HumanosRESUMO
Despite the increasing knowledge of pathophysiological mechanisms underlying the onset of type 1 diabetes (T1D), the quest for therapeutic options capable of delaying/reverting the diseases is still ongoing. Among all strategies currently tested in T1D, the use of hematopoietic stem cell (HSC)-based approaches and of teplizumab, showed the most encouraging results. Few clinical trials have already demonstrated the beneficial effects of HSCs in T1D, while the durability of the effect is yet to be established. Investigators are also trying to understand whether the use of selected and better-characterized HSCs subsets may provide more benefits with less risks. Interestingly, ex vivo manipulated HSCs showed promising results in murine models and the recent introduction of the humanized mouse models accelerated the translational potentials of such studies and their final road to clinic. Indeed, immunomodulatory as well as trafficking abilities can be enhanced in genetically modulated HSCs and genetically engineered HSCs may be viewed as a novel "biologic" therapy, to be further tested and explored in T1D and in other autoimmune/immune-related disorders.
Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Diabetes Mellitus Tipo 1/terapia , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas , Hipoglicemiantes/uso terapêutico , Animais , Anticorpos Monoclonais Humanizados/efeitos adversos , Diabetes Mellitus Tipo 1/imunologia , Diabetes Mellitus Tipo 1/metabolismo , Modelos Animais de Doenças , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Células-Tronco Hematopoéticas/imunologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Hipoglicemiantes/efeitos adversos , Camundongos , Fenótipo , Resultado do TratamentoRESUMO
Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.
Assuntos
Transplante de Coração , MicroRNAs , Aloenxertos , Animais , Rejeição de Enxerto/genética , Rejeição de Enxerto/prevenção & controle , Transplante de Coração/efeitos adversos , Humanos , Macrófagos , Camundongos , MicroRNAs/genéticaRESUMO
The prevalence of diabetes mellitus is rising among children and adolescents worldwide. Cardiovascular diseases are the main cause of morbidity and mortality in diabetic patients. We review the impact of diabetes on establishing, during childhood and adolescence, the premises for cardiovascular diseases later in life. Interestingly, it seems that hyperglycemia is not the only factor that establishes an increased cardiovascular risk in adolescence. Other factors have been recognized to play a role in triggering the onset of latent cardiovascular diseases in the pediatric population. Among these cardiovascular risk factors, some are modifiable: glucose variability, hypoglycemia, obesity, insulin resistance, waist circumference, hypertension, dyslipidemia, smoking alcohol, microalbuminuria and smoking. Others are unmodifiable, such as diabetes duration and family history. Among the etiological factors, subclinical endothelial dysfunction represents one of the earliest key players of atherosclerosis and it can be detected during early ages in patients with diabetes. A better assessment of cardiovascular risk in pediatric population still represents a challenge for clinicians, and thus further efforts are required to properly identify and treat pediatric patients who may suffer from cardiovascular disease later in early adulthood.
Assuntos
Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus/epidemiologia , Adolescente , Idade de Início , Consumo de Bebidas Alcoólicas/epidemiologia , Antropometria , Aterosclerose/epidemiologia , Aterosclerose/etiologia , Glicemia/análise , Criança , Comorbidade , Cardiomiopatias Diabéticas/epidemiologia , Cardiomiopatias Diabéticas/etiologia , Endotélio Vascular/fisiopatologia , Feminino , Humanos , Hipertensão/epidemiologia , Hipertrofia Ventricular Esquerda/epidemiologia , Hipertrofia Ventricular Esquerda/etiologia , Inflamação/epidemiologia , Resistência à Insulina , Masculino , Obesidade/epidemiologia , Prognóstico , Risco , Fatores de Risco , Fumar/epidemiologiaRESUMO
INTRODUCTION: Type 1 diabetes (T1D) is a lifelong condition resulting from autoimmune destruction of insulin-producing ß-cells. Islet or whole-pancreas transplantation is limited by the shortage of donors and need for chronic immune suppression. Novel strategies are needed to prevent ß-cell loss and to rescue production of endogenous insulin. AREAS COVERED: This review covers the latest advances in cell-based therapies for the treatment and prevention of T1D. Topics include adoptive transfer of cells with increased immunoregulatory potential for ß-cell protection, and ß-cell replacement strategies such as generation of insulin-producing ß-like cells from unlimited sources. EXPERT OPINION: Cell therapy provides an opportunity to prevent or reverse T1D. Adoptive transfer of autologous cells having enhanced immunomodulatory properties can suppress autoimmunity and preserve ß-cells. Such therapies have been made possible by a combination of genome-editing techniques and transplantation of tolerogenic cells. In-vitro modified autologous hematopoietic stem cells and tolerogenic dendritic cells may protect endogenous and newly generated ß-cells from a patient's autoimmune response without hampering immune surveillance for infectious agents and malignant cellular transformations. However, methods to generate cells that meet quality and safety standards for clinical applications require further refinement.
Assuntos
Terapia Baseada em Transplante de Células e Tecidos/métodos , Diabetes Mellitus Tipo 1/terapia , Animais , Diferenciação Celular , Diabetes Mellitus Tipo 1/patologia , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/transplante , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismo , Linfócitos T Reguladores/transplanteRESUMO
Chromogranin A (CgA), a secretory protein released in the blood by the neuroendocrine system, consists of a mixture of full-length molecules and fragments endowed of vasoregulatory activity. The extent and the role of CgA fragmentation were investigated in patients with locally advanced or metastatic pancreatic ductal adenocarcinoma (PDAC, n=172). Multivariate analysis showed that full-length CgA was associated with better progression free and overall survival, whereas CgA C-terminal fragmentation was associated with worse prognosis. In vitro studies showed that PDAC cells can promote the cleavage of CgA C-terminal region by activating plasminogen to plasmin. Limited digestion of full-length CgA with plasmin abolished its anti-angiogenic activity and generated pro-angiogenic molecules. The fragmentation of CgA C-terminal region was increased also in murine models of PDAC. In these models, the inhibition of CgA fragmentation with aprotinin, an inhibitor of plasmin and other serine proteases, or the blockade of pro-angiogenic fragments with specific antibodies inhibited the growth of PDAC implanted subcutaneously in mice. Finally, administration of full-length CgA to mice bearing orthotopic PDAC reduced tumor perfusion, as measured by contrast-enhanced ultrasound. These findings suggest that PDAC can promote the cleavage of circulating CgA C-terminal region to generate fragments that regulate the tumor vascular biology and that may represent new potential therapeutic targets.
RESUMO
Hematopoietic stem and progenitor cells (HSPCs) are multipotent stem cells that have been harnessed as a curative therapy for patients with hematological malignancies. Notably, the discovery that HSPCs are endowed with immunoregulatory properties suggests that HSPC-based therapeutic approaches may be used to treat autoimmune diseases. Indeed, infusion with HSPCs has shown promising results in the treatment of type 1 diabetes (T1D) and remains the only "experimental therapy" that has achieved a satisfactory rate of remission (nearly 60%) in T1D. Patients with newly diagnosed T1D have been successfully reverted to normoglycemia by administration of autologous HSPCs in association with a non-myeloablative immunosuppressive regimen. However, this approach is hampered by a high incidence of adverse effects linked to immunosuppression. Herein, we report that while the use of autologous HSPCs is capable of improving C-peptide production in patients with T1D, ex vivo modulation of HSPCs with prostaglandins (PGs) increases their immunoregulatory properties by upregulating expression of the immune checkpoint-signaling molecule PD-L1. Surprisingly, CXCR4 was upregulated as well, which could enhance HSPC trafficking toward the inflamed pancreatic zone. When tested in murine and human in vitro autoimmune assays, PG-modulated HSPCs were shown to abrogate the autoreactive T cell response. The use of PG-modulated HSPCs may thus provide an attractive and novel treatment of autoimmune diabetes.
RESUMO
BACKGROUND: Chromogranin A (CgA), a circulating protein released by the neuroendocrine system, can regulate vascular physiology and angiogenesis. Full-length CgA (CgA1-439) and its fragment CgA1-76 (called vasostatin-1, VS-1) preserve the physiological integrity of the endothelial barrier function and are antiangiogenic, whereas CgA1-373 is proangiogenic. We investigated whether these polypeptides are altered in patients with various degrees of carotid artery atherosclerosis. METHODS: We studied 81 patients with carotid artery atherosclerosis, asymptomatic for cerebrovascular diseases. Carotid arteries were examined by Doppler ultrasound and plaque characteristics were recorded. Plasma levels of CgA1-439, VS-1, CgA1-373, and total-CgA (CgA1-439 plus truncated fragments lacking part or the entire C-terminal region) were assessed by specific ELISAs. RESULTS: Plasma levels of VS-1 and total-CgA correlated with carotid artery maximum stenosis (r=0.349, p=0.001 and r=0.256, p=0.021, respectively). Stepwise multiple regression analysis indicated that VS-1 was a significant predictor of maximum stenosis after adjustment for age, gender, and conventional risk factors for atherosclerosis (regression coefficient=12.42, SE=4.84, p=0.012). In addition, logistic regression analysis indicated that relatively high levels of full-length CgA, but not total-CgA, predict the presence of hypoechoic, lipid-rich plaques (OR=1.47; 95% CI: 1.19-1.81, p=0.0003). CONCLUSION: VS-1 is independently associated with carotid artery maximum stenosis. Furthermore, full-length CgA is an independent indicator of hypoechoic plaques, likely reflecting initial stages of atherosclerosis. Given the known capability of CgA and VS-1 to regulate vascular function and angiogenesis these polypeptides might play a role in the regulation of atherosclerosis pathophysiology.
Assuntos
Artéria Carótida Primitiva/diagnóstico por imagem , Estenose das Carótidas/sangue , Estenose das Carótidas/diagnóstico por imagem , Cromogranina A/sangue , Fragmentos de Peptídeos/sangue , Biomarcadores/sangue , Doenças das Artérias Carótidas/sangue , Doenças das Artérias Carótidas/diagnóstico por imagem , Feminino , Humanos , Masculino , Projetos Piloto , Ultrassonografia DopplerRESUMO
Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of leukemic B cells in peripheral blood, bone marrow (BM) and lymphoid tissues, and by their recirculation between these compartments. We observed that circulating chromogranin A (CgA) and its N-terminal fragment (called vasostatin-1, CgA1-76), two neuroendocrine secretory polypeptides that enhance the endothelial barrier function, are present in variable amounts in the blood of CLL patients. Studies in animal models showed that daily administration of full-length human CgA1-439 (0.3 µg, i.v., or 1.5 µg/mouse, i.p.) can reduce the BM/blood ratio of leukemic cells in Eµ-TCL1 mice, a transgenic model, and decrease BM, lung and kidney infiltration in Rag2-/-γc-/- mice engrafted with human MEC1 CLL cells, a xenograft model. This treatment also reduced the loss of body weight and improved animal motility. In vitro, CgA enhanced the endothelial barrier integrity and the trans-endothelial migration of MEC1 cells, with a bimodal dose-response curve. Vasostatin-1, but not a larger fragment consisting of N-terminal and central regions of CgA (CgA1-373), inhibited CLL progression in the xenograft model, suggesting that the C-terminal region is crucial for CgA activity and that the N-terminal domain contains a site that is activated by proteolytic cleavage. These findings suggest that circulating full-length CgA and its fragments may contribute to regulate leukemic cell trafficking and reduce tissue infiltration in CLL.
Assuntos
Cromogranina A/farmacologia , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Fragmentos de Peptídeos/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Idoso , Animais , Linhagem Celular Tumoral , Movimento Celular , Células Cultivadas , Cromogranina A/sangue , Cromogranina A/química , Progressão da Doença , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/patologia , Masculino , Camundongos Knockout , Camundongos Transgênicos , Pessoa de Meia-Idade , Inibidores da Bomba de Prótons/uso terapêuticoRESUMO
The sphingolipid metabolising enzyme Acid Sphingomyelinase (A-SMase) has been recently shown to inhibit melanoma progression and correlate inversely to tumour grade. In this study we have investigated the role of A-SMase in the chemo-resistance to anticancer treatmentusing mice with melanoma allografts and melanoma cells differing in terms of expression/activity of A-SMase. Since autophagy is emerging as a key mechanism in tumour growth and chemo-resistance, we have also investigated whether an action of A-SMase in autophagy can explain its role. Melanoma sensitivity to chemotherapeutic agent cisplatin in terms of cell viability/apoptosis, tumour growth, and animal survival depended directly on the A-SMase levels in tumoural cells. A-SMase action was due to inhibition of autophagy through activation of Akt/mammalian target of rapamycin (mTOR) pathway. Treatment of melanoma-bearing mice with the autophagy inhibitor chloroquine restored sensitivity to cisplatin of tumours expressing low levels of A-SMase while no additive effects were observed in tumours characterised by sustained A-SMase levels. The fact that A-SMase in melanomas affects mTOR-regulated autophagy and plays a central role in cisplatin efficacy encourages pre-clinical testing on the modulation of A-SMase levels/activity as possible novel anti-neoplastic strategy.
Assuntos
Antineoplásicos/farmacologia , Autofagia/efeitos dos fármacos , Cisplatino/farmacologia , Melanoma/enzimologia , Esfingomielina Fosfodiesterase/metabolismo , Animais , Resistencia a Medicamentos Antineoplásicos/fisiologia , Humanos , Melanoma/patologia , Camundongos , Serina-Treonina Quinases TOR/metabolismoRESUMO
The inflammatory microenvironment induces tumours to acquire an aggressive and immunosuppressive behaviour. Since acid sphingomyelinase (A-SMase) downregulation in melanoma was shown to determine a malignant phenotype, we aimed here to elucidate the role of A-SMase in the regulation of tumour immunogenic microenvironment using in vivo melanoma models in which A-SMase was either downregulated or maintained at constitutively high levels. We found high levels of inflammatory factors in low A-SMase expressing tumours, which also displayed an immunosuppressive/protumoural microenvironment: high levels of myeloid-derived suppressor cells (MDSCs) and regulatory T lymphocytes (Tregs), as well as low levels of dendritic cells (DCs). In contrast, the restoration of A-SMase in melanoma cells not only reduced tumour growth and immunosuppression, but also induced a high recruitment at tumour site of effector immune cells with an antitumoural function. Indeed, we observed a poor homing of MDSCs and Tregs and the increased recruitment of CD8(+) and CD4(+) T lymphocytes as well as the infiltration of DCs and CD8(+)/CD44(high) T lymphocytes. This study demonstrates that change of A-SMase expression in cancer cells is sufficient per se to tune in vivo melanoma growth and that A-SMase levels modulate immune cells at tumour site. This may be taken into consideration in the setting of therapeutic strategies.
Assuntos
Reprogramação Celular , Melanoma Experimental/imunologia , Esfingomielina Fosfodiesterase/fisiologia , Microambiente Tumoral , Animais , Linfócitos T CD8-Positivos/imunologia , Proliferação de Células , Feminino , Tolerância Imunológica , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Autophagy, the main intracellular process of cytoplasmic material degradation, is involved in cell survival and death. Autophagy is regulated at various levels and novel modulators of its function are being continuously identified. An intriguing recent observation is that among these modulators is the sphingolipid metabolising enzyme, Acid Sphingomyelinase (A-SMase), already known to play a fundamental role in apoptotic cell death participating in several pathophysiological conditions. In this review we analyse and discuss the relationship between autophagy and A-SMase describing how A-SMase may regulate it and defining, for the first time, the existence of an A-SMase-autophagy axis. The imbalance of this axis plays a role in cancer, nervous system, cardiovascular, and hepatic disorders.
Assuntos
Autofagia , Esfingomielina Fosfodiesterase/fisiologia , Animais , Doenças Cardiovasculares/enzimologia , Doenças Cardiovasculares/patologia , Doenças do Sistema Nervoso Central/enzimologia , Doenças do Sistema Nervoso Central/patologia , Humanos , Neoplasias/enzimologia , Neoplasias/patologiaRESUMO
The endocrine system participates in regulating macrophage maturation, although little is known about the modulating role of the thyroid hormones. In vitro results demonstrate a negative role of one such hormone, triiodothyronine (T3), in triggering the differentiation of bone marrow-derived monocytes into unpolarized macrophages. T3-induced macrophages displayed a classically activated (M1) signature. A T3-induced M1-priming effect was also observed on polarized macrophages because T3 reverses alternatively activated (M2) activation, whereas it enhances that of M1 cells. In vivo, circulating T3 increased the content of the resident macrophages in the peritoneal cavity, whereas it reduced the content of the recruited monocyte-derived cells. Of interest, T3 significantly protected mice against endotoxemia induced by lipopolysaccharide i.p. injection; in these damaged animals, decreased T3 levels increased the recruited (potentially damaging) cells, whereas restoring T3 levels decreased recruited and increased resident (potentially beneficial) cells. These data suggest that the anti-inflammatory effect of T3 is coupled to the modulation of peritoneal macrophage content, in a context not fully explained by the M1/M2 framework. Thyroid hormone receptor expression analysis and the use of different thyroid hormone receptor antagonists suggest thyroid hormone receptor ß1 as the major player mediating T3 effects on macrophages. The novel homeostatic link between thyroid hormones and the pathophysiological role of macrophages opens new perspectives on the interactions between the endocrine and immune systems.
Assuntos
Inflamação/imunologia , Macrófagos/citologia , Macrófagos/imunologia , Tri-Iodotironina/imunologia , Tri-Iodotironina/metabolismo , Animais , Western Blotting , Diferenciação Celular/imunologia , Células Cultivadas , Feminino , Citometria de Fluxo , Imunofenotipagem , Ativação de Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Sphingolipid metabolism is deeply regulated along the differentiation and development of the central nervous system (CNS), and the expression of a peculiar spatially and temporarily regulated sphingolipid pattern is essential for the maintenance of the functional integrity of the nervous system. Microglia are resident macrophages of the CNS involved in general maintenance of neural environment. Modulations in microglia phenotypes may contribute to pathogenic forms of inflammation. Since defects in macrophage/microglia activity contribute to neurodegenerative diseases, it will be essential to systematically identify the components of the microglial cell response that contribute to disease progression. In such complex processes, the sphingolipid systems have recently emerged to play important roles, thus appearing as a key new player in CNS disorders. This review provides a rationale for harnessing the sphingolipid metabolic pathway as a potential target against neuroinflammation.
Assuntos
Encéfalo/metabolismo , Encéfalo/patologia , Inflamação/metabolismo , Inflamação/patologia , Macrófagos/metabolismo , Esfingolipídeos/metabolismo , Animais , Encéfalo/imunologia , Sistema Nervoso Central/imunologia , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Doenças do Sistema Nervoso Central/imunologia , Doenças do Sistema Nervoso Central/metabolismo , Doenças do Sistema Nervoso Central/patologia , Humanos , Inflamação/imunologia , Macrófagos/imunologia , Microglia/imunologia , Microglia/metabolismoRESUMO
The occurrence of renal cell carcinoma (RCC) in Fabry disease (FD) is a rare event. We report a deep ultrastructural study of RCC in a patient with a previous histological diagnosis of FD. In order to highlight analogies and differences between the two histological samples, we used the nephrectomy specimen as a 'repeat biopsy', making a dynamic analysis of the evolution of the disease-related kidney damage. Secondly, a comparative ultrastructural analysis between non-neoplastic tissue and cancer demonstrated for the first time the presence of zebra bodies in the tumor cells. Finally, a hypothetical speculation about the relationship between the lysosomal accumulation, the oxidative damage and the genesis of the tumor was performed. The link connected the accumulation of glycosphingolipid globotriaosylceramide, characteristic of FD, with the expression of CD74 and macrophage migration inhibitory factor that may play an important role in tumorigenesis regulated by the Von Hippel-Lindau/hypoxia-inducible factor 1α pathway.