RESUMO
Alzheimer's disease (AD) is linked to toxic Aß plaques in the brain and activation of innate responses. Recent findings however suggest that the disease may also depend on the adaptive immunity, as B cells exacerbate and CD8+ T cells limit AD-like pathology in mouse models of amyloidosis. Here, by artificially blocking or augmenting CD8+ T cells in the brain of 5xFAD mice, we provide evidence that AD-like pathology is promoted by pathogenic, proinflammatory cytokines and exhaustion markers expressing CXCR6+ CD39+CD73+/- CD8+ TRM-like cells. The CD8+ T cells appear to act by targeting disease associated microglia (DAM), as we find them in tight complexes with microglia around Aß plaques in the brain of mice and humans with AD. We also report that these CD8+ T cells are induced by B cells in the periphery, further underscoring the pathogenic importance of the adaptive immunity in AD. We propose that CD8+ T cells and B cells should be considered as therapeutic targets for control of AD, as their ablation at the onset of AD is sufficient to decrease CD8+ T cells in the brain and block the amyloidosis-linked neurodegeneration.
RESUMO
Short telomeres are a defining feature of telomere biology disorders (TBDs), including dyskeratosis congenita (DC), for which there is no effective general cure. Patients with TBDs often experience bone marrow failure. NAD, an essential metabolic coenzyme, is decreased in models of DC. Herein, using telomerase reverse transcriptase null (Tert-/-) mice with critically short telomeres, we investigated the effect of NAD supplementation with the NAD precursor, nicotinamide riboside (NR), on features of health span disrupted by telomere impairment. Our results revealed that NR ameliorated body weight loss in Tert-/- mice and improved telomere integrity and telomere dysfunction-induced systemic inflammation. NR supplementation also mitigated myeloid skewing of Tert-/- hematopoietic stem cells. Furthermore, NR alleviated villous atrophy and inflammation in the small intestine of Tert-/- transplant recipient mice. Altogether, our findings support NAD intervention as a potential therapeutic strategy to enhance aspects of health span compromised by telomere attrition.
Assuntos
Disceratose Congênita , Transplante de Células-Tronco Hematopoéticas , Humanos , Animais , Camundongos , NAD , Telômero/metabolismo , Disceratose Congênita/genética , Disceratose Congênita/metabolismo , InflamaçãoRESUMO
We have recently reported that some cancers induce accumulation of bone marrow (BM) B-cell precursors in the spleen to convert them into metastasis-promoting, immunosuppressive B cells. Here, using various murine tumor models and samples from humans with breast and ovarian cancers, we provide evidence that cancers also co-opt differentiation of these B-cell precursors to generate macrophage-like cells (termed B-MF). We link the transdifferentiation to a small subset of CSF1R+ Pax5Low cells within BM pre-B and immature B cells responding to cancer-secreted M-CSF with downregulation of the transcription factor Pax5 via CSF1R signaling. Although the primary source of tumor-associated macrophages is monocytes, B-MFs are phenotypically and functionally distinguishable. Compared to monocyte-derived macrophages, B-MFs more efficiently phagocytize apoptotic cells, suppress proliferation of T cells and induce FoxP3+ regulatory T cells. In mouse tumor models, B-MFs promote shrinkage of the tumor-infiltrating IFNγ+ CD4 T cell pool and increase cancer progression and metastasis, suggesting that this cancer-induced transdifferentiation pathway is functionally relevant and hence could serve as an immunotherapeutic target.
Assuntos
Macrófagos , Neoplasias , Animais , Linfócitos B , Diferenciação Celular , Humanos , Camundongos , MonócitosRESUMO
Caloric restriction (CR) is the leading non-pharmacological intervention to delay induced and spontaneous tumors in pre-clinical models. These effects of CR are largely attributed to canonical inhibition of pro-growth pathways. However, our recent data suggest that CR impairs primary tumor growth and cancer progression in the murine 4T1 model of triple negative breast cancer (TNBC), at least in part, through reduced frequency of the myeloid-derived suppressor cells (MDSC). In the present study, we sought to determine whether injection of excess MDSCs could block regression in 4T1 tumor growth and metastatic spread in BALB/cJ female mice undergoing daily CR. Our findings show that MDSC injection impeded CR-mediated protection against tumor growth without increasing lung metastatic burden. Overall, these results reveal that CR can slow cancer progression by affecting immune suppressive cells.Impact statement: Inoculation of MDSCs from donor mice effectively impedes the ability of calorie restriction to protect against primary tumor growth without impacting lung metastatic burden in recipient animals.
Assuntos
Células Supressoras Mieloides , Neoplasias de Mama Triplo Negativas , Humanos , Feminino , Camundongos , Animais , Células Supressoras Mieloides/metabolismo , Células Supressoras Mieloides/patologia , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Restrição Calórica , Modelos Animais de Doenças , Linhagem Celular TumoralRESUMO
Cancer incidence increases with age and is a leading cause of death. Caloric restriction (CR) confers benefits on health and survival and delays cancer. However, due to CR's stringency, dietary alternatives offering the same cancer protection have become increasingly attractive. Short cycles of a plant-based diet designed to mimic fasting (FMD) are protective against tumorigenesis without the chronic restriction of calories. Yet, it is unclear whether the fasting time, level of dietary restriction, or nutrient composition is the primary driver behind cancer protection. Using a breast cancer model in mice, we compare the potency of daily CR to that of periodic caloric cycling on FMD or an isocaloric standard laboratory chow against primary tumor growth and metastatic burden. Here, we report that daily CR provides greater protection against tumor growth and metastasis to the lung, which may be in part due to the unique immune signature observed with daily CR.
Assuntos
Restrição Calórica/métodos , Neoplasias Pulmonares/prevenção & controle , Neoplasias Mamárias Experimentais/dietoterapia , Animais , Linhagem Celular Tumoral , Jejum , Feminino , Neoplasias Pulmonares/secundário , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Carga Tumoral , Microambiente Tumoral/imunologiaRESUMO
The function of B cells in Alzheimer's disease (AD) is not fully understood. While immunoglobulins that target amyloid beta (Aß) may interfere with plaque formation and hence progression of the disease, B cells may contribute beyond merely producing immunoglobulins. Here we show that AD is associated with accumulation of activated B cells in circulation, and with infiltration of B cells into the brain parenchyma, resulting in immunoglobulin deposits around Aß plaques. Using three different murine transgenic models, we provide counterintuitive evidence that the AD progression requires B cells. Despite expression of the AD-fostering transgenes, the loss of B cells alone is sufficient to reduce Aß plaque burden and disease-associated microglia. It reverses behavioral and memory deficits and restores TGFß+ microglia, respectively. Moreover, therapeutic depletion of B cells at the onset of the disease retards AD progression in mice, suggesting that targeting B cells may also benefit AD patients.
Assuntos
Doença de Alzheimer/imunologia , Doença de Alzheimer/patologia , Linfócitos B/imunologia , Progressão da Doença , Depleção Linfocítica , Peptídeos beta-Amiloides/metabolismo , Animais , Feminino , Hipocampo/patologia , Humanos , Interleucina-1beta/metabolismo , Ativação Linfocitária/imunologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microglia/metabolismo , Fenótipo , Placa Amiloide/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
Immature B cells in the bone marrow emigrate into the spleen during adult lymphopoiesis. Here, we report that emigration is shifted to earlier B-cell stages in mice with orthotopic breast cancer, spontaneous ovarian cancer, and possibly in human breast carcinoma. Using mouse and human bone marrow aspirates and mouse models challenged with highly metastatic 4T1 breast cancer cells, we demonstrated that this was the result of secretion of thymic stromal lymphopoietin (TSLP) by cancer cells. First, TSLP downregulated surface expression of bone marrow (BM) retention receptors CXCR4 and VLA4 in B-cell precursors, increasing their motility and, presumably, emigration. Then, TSLP supported peripheral survival and proliferation of BM B-cell precursors such as pre-B-like cells. 4T1 cancer cells used the increased pool of circulating pre-B-like cells to generate metastasis-supporting regulatory B cells. As such, the loss of TSLP expression in cancer cells alone or TSLPR deficiency in B cells blocked both accumulation of pre-B-like cells in circulation and cancer metastasis, implying that the pre-B cell-TSLP axis can be an attractive therapeutic target. SIGNIFICANCE: Cancer cells induce premature emigration of B-cell precursors from the bone marrow to generate regulatory B cells.
Assuntos
Linfócitos B/metabolismo , Medula Óssea/metabolismo , Citocinas/metabolismo , Metástase Neoplásica/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Células Precursoras de Linfócitos B/metabolismo , Animais , Proliferação de Células/fisiologia , Feminino , Humanos , Leucócitos Mononucleares/metabolismo , Linfopoese/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Baço/metabolismo , Linfopoietina do Estroma do TimoRESUMO
Aging in humans is associated with increased hyperglycemia and insulin resistance (collectively termed IR) and dysregulation of the immune system. However, the causative factors underlying their association remain unknown. Here, using "healthy" aged mice and macaques, we found that IR was induced by activated innate 4-1BBL+ B1a cells. These cells (also known as 4BL cells) accumulated in aging in response to changes in gut commensals and a decrease in beneficial metabolites such as butyrate. We found evidence suggesting that loss of the commensal bacterium Akkermansia muciniphila impaired intestinal integrity, causing leakage of bacterial products such as endotoxin, which activated CCR2+ monocytes when butyrate was decreased. Upon infiltration into the omentum, CCR2+ monocytes converted B1a cells into 4BL cells, which, in turn, induced IR by expressing 4-1BBL, presumably to trigger 4-1BB receptor signaling as in obesity-induced metabolic disorders. This pathway and IR were reversible, as supplementation with either A. muciniphila or the antibiotic enrofloxacin, which increased the abundance of A. muciniphila, restored normal insulin response in aged mice and macaques. In addition, treatment with butyrate or antibodies that depleted CCR2+ monocytes or 4BL cells had the same effect on IR. These results underscore the pathological function of B1a cells and suggest that the microbiome-monocyte-B cell axis could potentially be targeted to reverse age-associated IR.
Assuntos
Envelhecimento/imunologia , Bactérias/imunologia , Imunidade Inata , Resistência à Insulina , Animais , Bactérias/efeitos dos fármacos , Butiratos/farmacologia , Linhagem Celular , Disbiose/microbiologia , Enrofloxacina/farmacologia , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Macaca , Camundongos Endogâmicos C57BL , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Omento/metabolismo , Receptores CCR2/metabolismoAssuntos
Anticorpos Monoclonais/uso terapêutico , Vacinas Anticâncer/imunologia , Células Dendríticas/imunologia , Imunoterapia/métodos , Linfócitos do Interstício Tumoral/fisiologia , Neoplasias/terapia , Linfócitos T/fisiologia , Animais , Antígenos de Neoplasias/imunologia , Células Dendríticas/transplante , Humanos , Interferon-alfa/metabolismo , Linfócitos do Interstício Tumoral/transplante , Neoplasias/imunologia , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/transplanteRESUMO
The senescence-associated secretory phenotype (SASP) is a major trait of senescent cells, but the molecular regulators of SASP factor secretion are poorly understood. Mass spectrometry analysis revealed that secretory carrier membrane protein 4 (SCAMP4) levels were strikingly elevated on the surface of senescent cells compared with proliferating cells. Interestingly, silencing SCAMP4 in senescent fibroblasts reduced the secretion of SASP factors, including interleukin 6 (IL6), IL8, growth differentiation factor 15 (GDF-15), C-X-C motif chemokine ligand 1 (CXCL1), and IL7, while, conversely, SCAMP4 overexpression in proliferating fibroblasts increased SASP factor secretion. Our results indicate that SCAMP4 accumulates on the surface of senescent cells, promotes SASP factor secretion, and critically enhances the SASP phenotype.
Assuntos
Proteínas de Transporte/metabolismo , Senescência Celular/genética , Fibroblastos/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Transporte/genética , Linhagem Celular , Proliferação de Células/fisiologia , Fibroblastos/citologia , Inativação Gênica , Humanos , Proteínas de Membrana/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Ubiquitina/metabolismoRESUMO
Type 2 diabetes is a chronic age-associated degenerative metabolic disease that reflects relative insulin deficiency and resistance. Extracellular vesicles (EVs) (exosomes, microvesicles, and apoptotic bodies) are small (30-400 nm) lipid-bound vesicles capable of shuttling functional proteins, nucleic acids, and lipids as part of intercellular communication systems. Recent studies in mouse models and in cell culture suggest that EVs may modulate insulin signaling. Here, we designed cross-sectional and longitudinal cohorts of euglycemic participants and participants with prediabetes or diabetes. Individuals with diabetes had significantly higher levels of EVs in their circulation than euglycemic control participants. Using a cell-specific EV assay, we identified that levels of erythrocyte-derived EVs are higher with diabetes. We found that insulin resistance increases EV secretion. Furthermore, the levels of insulin signaling proteins were altered in EVs from individuals with high levels of insulin resistance and ß-cell dysfunction. Moreover, EVs from individuals with diabetes were preferentially internalized by circulating leukocytes. Cytokine levels in the media and in EVs were higher from monocytes incubated with diabetic EVs. Microarray of these leukocytes revealed altered gene expression pathways related to cell survival, oxidative stress, and immune function. Collectively, these results suggest that insulin resistance increases the secretion of EVs, which are preferentially internalized by leukocytes, and alters leukocyte function.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Vesículas Extracelulares/metabolismo , Resistência à Insulina/fisiologia , Células Secretoras de Insulina/metabolismo , Adulto , Idoso , Citocinas/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Senescent cell accumulation in aging tissues is linked to age-associated diseases and declining function, prompting efforts to eliminate them. Mass spectrometry analysis revealed that DPP4 (dipeptidyl peptidase 4) was selectively expressed on the surface of senescent, but not proliferating, human diploid fibroblasts. Importantly, the differential presence of DPP4 allowed flow cytometry-mediated isolation of senescent cells using anti-DPP4 antibodies. Moreover, antibody-dependent cell-mediated cytotoxicity (ADCC) assays revealed that the cell surface DPP4 preferentially sensitized senescent, but not dividing, fibroblasts to cytotoxicity by natural killer cells. In sum, the selective expression of DPP4 on the surface of senescent cells enables their preferential elimination.
Assuntos
Senescência Celular/fisiologia , Dipeptidil Peptidase 4/metabolismo , Proteínas de Membrana/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Citotoxicidade Celular Dependente de Anticorpos , Células Cultivadas , Inibidor p16 de Quinase Dependente de Ciclina/genética , Diploide , Fibroblastos/metabolismo , Citometria de Fluxo , Humanos , Células Matadoras Naturais/metabolismo , Subpopulações de Linfócitos/enzimologia , Espectrometria de Massas , RNA Mensageiro/metabolismo , RNA Ribossômico/metabolismoRESUMO
Cells release lipid-bound extracellular vesicles (EVs; exosomes, microvesicles and apoptotic bodies) containing proteins, lipids and RNAs into the circulation. Vesicles mediate intercellular communication between both neighboring and distant cells. There is substantial interest in using EVs as biomarkers for age-related diseases including cancer, and neurodegenerative, metabolic and cardiovascular diseases. The majority of research focuses on identifying differences in EVs when comparing disease states and matched controls. Here, we analyzed circulating plasma EVs in a cross-sectional and longitudinal study in order to address age-related changes in community-dwelling individuals. We found that EV concentration decreases with advancing age. Furthermore, EVs from older individuals were more readily internalized by B cells and increased MHC-II expression on monocytes compared with EVs from younger individuals, indicating that the decreased concentration of EVs with age may be due in part to increased internalization. EVs activated both monocytes and B cells, and activation of B cells by LPS enhanced EV internalization. We also report a relative stability of EV concentration and protein amount in individual subjects over time. Our data provide important information towards establishing a profile of EVs with human age, which will further aid in the development of EV-based diagnostics for aging and age-related diseases.
Assuntos
Vesículas Extracelulares/metabolismo , Leucócitos Mononucleares/metabolismo , Adulto , Idoso , Linfócitos B/metabolismo , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-IdadeRESUMO
B cell dysregulation in aging is thought to mostly occur in conventional B2 cells without affecting innate B1 cells. Elderly humans and mice also accumulate 4-1BBL(+)MHC class-I(Hi)CD86(Hi)B cells of unknown origin. In this article, we report that these cells, termed 4BL cells, are activated murine and possibly human B1a cells. The activation is mediated by aging human monocytes and murine peritoneal macrophages. They induce expression and activation of 4-1BBL and IFN-γR1 on B1a cells to subsequently upregulate membrane TNF-α and CD86. As a result, activated B1a/4BL cells induce expression of granzyme B in CD8(+)T cells by targeting TNFR2 via membrane TNF-α and providing costimulation with CD86. Thus, for the first time, to our knowledge, these results indicate that aging affects the function of B1a cells. Upon aging, these cells lose their tumor-supporting activity and become inducers of potentially antitumor and autoimmune CD8(+)T cells.
Assuntos
Envelhecimento/imunologia , Subpopulações de Linfócitos B/citologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Ativação Linfocitária/imunologia , Ligante 4-1BB/metabolismo , Adulto , Idoso , Animais , Autoimunidade/imunologia , Subpopulações de Linfócitos B/imunologia , Antígeno B7-2/biossíntese , Antígeno B7-2/metabolismo , Células Cultivadas , Senescência Celular , Ativação Enzimática/imunologia , Feminino , Granzimas/biossíntese , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Macrófagos Peritoneais/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Monócitos/imunologia , Neoplasias/imunologia , Neoplasias/patologia , Receptores de Interferon/biossíntese , Receptores de Interferon/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/metabolismo , Receptor de Interferon gamaRESUMO
Myeloid-derived suppressive cells (MDSC) have been reported to promote metastasis, but the loss of cancer-induced B cells/B regulatory cells (tBreg) can block metastasis despite MDSC expansion in cancer. Here, using multiple murine tumor models and human MDSC, we show that MDSC populations that expand in cancer have only partially primed regulatory function and limited prometastatic activity unless they are fully educated by tBregs. Cancer-induced tBregs directly activate the regulatory function of both the monocyte and granulocyte subpopulations of MDSC, relying, in part, on TgfßR1/TgfßR2 signaling. MDSC fully educated in this manner exhibit an increased production of reactive oxygen species and NO and more efficiently suppress CD4(+) and CD8(+) T cells, thereby promoting tumor growth and metastasis. Thus, loss of tBregs or TgfßR deficiency in MDSC is sufficient to disable their suppressive function and to block metastasis. Overall, our data indicate that cancer-induced B cells/B regulatory cells are important regulators of the immunosuppressive and prometastatic functions of MDSC.
Assuntos
Linfócitos B Reguladores/imunologia , Terapia de Imunossupressão , Melanoma Experimental/imunologia , Células Mieloides/imunologia , Animais , Linfócitos B Reguladores/patologia , Linhagem da Célula/imunologia , Modelos Animais de Doenças , Granulócitos/imunologia , Granulócitos/patologia , Humanos , Melanoma Experimental/patologia , Camundongos , Monócitos/imunologia , Monócitos/patologia , Células Mieloides/patologia , Proteínas Serina-Treonina Quinases/imunologia , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Fatores de Crescimento Transformadores beta/imunologia , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Transdução de Sinais/imunologiaRESUMO
The ketone bodies ß-hydroxybutyrate (BHB) and acetoacetate (AcAc) support mammalian survival during states of energy deficit by serving as alternative sources of ATP. BHB levels are elevated by starvation, caloric restriction, high-intensity exercise, or the low-carbohydrate ketogenic diet. Prolonged fasting reduces inflammation; however, the impact that ketones and other alternative metabolic fuels produced during energy deficits have on the innate immune response is unknown. We report that BHB, but neither AcAc nor the structurally related short-chain fatty acids butyrate and acetate, suppresses activation of the NLRP3 inflammasome in response to urate crystals, ATP and lipotoxic fatty acids. BHB did not inhibit caspase-1 activation in response to pathogens that activate the NLR family, CARD domain containing 4 (NLRC4) or absent in melanoma 2 (AIM2) inflammasome and did not affect non-canonical caspase-11, inflammasome activation. Mechanistically, BHB inhibits the NLRP3 inflammasome by preventing K(+) efflux and reducing ASC oligomerization and speck formation. The inhibitory effects of BHB on NLRP3 are not dependent on chirality or starvation-regulated mechanisms like AMP-activated protein kinase (AMPK), reactive oxygen species (ROS), autophagy or glycolytic inhibition. BHB blocks the NLRP3 inflammasome without undergoing oxidation in the TCA cycle, and independently of uncoupling protein-2 (UCP2), sirtuin-2 (SIRT2), the G protein-coupled receptor GPR109A or hydrocaboxylic acid receptor 2 (HCAR2). BHB reduces NLRP3 inflammasome-mediated interleukin (IL)-1ß and IL-18 production in human monocytes. In vivo, BHB or a ketogenic diet attenuates caspase-1 activation and IL-1ß secretion in mouse models of NLRP3-mediated diseases such as Muckle-Wells syndrome, familial cold autoinflammatory syndrome and urate crystal-induced peritonitis. Our findings suggest that the anti-inflammatory effects of caloric restriction or ketogenic diets may be linked to BHB-mediated inhibition of the NLRP3 inflammasome.
Assuntos
Ácido 3-Hidroxibutírico/farmacologia , Proteínas de Transporte/antagonistas & inibidores , Caspase 1/efeitos dos fármacos , Síndromes Periódicas Associadas à Criopirina , Inflamassomos/antagonistas & inibidores , Interleucina-1beta/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Adulto , Idoso , Animais , Dieta Cetogênica , Modelos Animais de Doenças , Feminino , Humanos , Inflamação , Interleucina-18 , Interleucina-1beta/metabolismo , Masculino , Camundongos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Potássio/metabolismoRESUMO
The symbiotic nitrogen-fixing soil bacterium Sinorhizobium meliloti carries a large number of toxin-antitoxin (TA) modules both on the chromosome and megaplasmids. One of them, the vapBC-5 module that belongs to the type II systems was characterized here. It encodes an active toxin vapC-5, and was shown to be controlled negatively by the complex of its own proteins. Different mutants of the vapBC-5 genes exhibited diverse effects on symbiotic efficiency during interaction with the host plant Medicago sativa. The absence of the entire vapBC-5 region had no influence on nodule formation and nitrogen fixation properties. The strain carrying an insertion in the antitoxin gene showed a reduced nitrogen fixation capacity resulting in a lower plant yield. In contrast, when the toxin gene was mutated, the strain developed more efficient symbiosis with the host plant. The nitrogen fixing root nodules had a delayed senescent phenotype and contained elevated level of plant-derived molecules characteristic of later steps of nodule development. The longer bacteroid viability and abundance of active nitrogen fixing zone resulted in increased production of plant material. These data indicate that modification of the toxin/antitoxin production may influence bacteroid metabolism and may have an impact on the adaptation to changing environmental conditions.
Assuntos
Antitoxinas/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Medicago sativa/microbiologia , Sinorhizobium meliloti/genética , Sinorhizobium meliloti/fisiologia , Simbiose , Antitoxinas/metabolismo , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Medicago sativa/crescimento & desenvolvimento , Medicago sativa/fisiologia , Mutação , Fixação de Nitrogênio/genética , Óperon , Fenótipo , Nódulos Radiculares de Plantas/crescimento & desenvolvimento , Nódulos Radiculares de Plantas/microbiologiaRESUMO
Although the accumulation of highly-differentiated and granzyme B (GrB)-expressing CD8(+)CD28(-) T cells has been associated with aging, the mechanism for their enrichment and contribution to immune function remains poorly understood. Here we report a novel B-cell subset expressing 4-1BBL, which increases with age in humans, rhesus macaques, and mice, and with immune reconstitution after chemotherapy and autologous progenitor cell transplantation. These cells (termed 4BL cells) induce GrB(+)CD8(+) T cells by presenting endogenous antigens and using the 4-1BBL/4-1BB axis. We found that the 4BL cells increase antitumor responses in old mice, which may explain in part the paradox of retarded tumor growth in the elderly. 4BL cell accumulation and its capacity to evoke the generation of GrB(+)CD8(+) T cells can be eliminated by inducing reconstitution of B cells in old mice, suggesting that the age-associated skewed cellular immune responses are reversible. We propose that 4BL cells and the 4-1BBL signaling pathway are useful targets for improved effectiveness of natural antitumor defenses and therapeutic immune manipulations in the elderly.
Assuntos
Ligante 4-1BB/metabolismo , Envelhecimento/imunologia , Subpopulações de Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , Granzimas/metabolismo , Ligante 4-1BB/deficiência , Ligante 4-1BB/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/metabolismo , Envelhecimento/patologia , Animais , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/metabolismo , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/enzimologia , Feminino , Humanos , Imunidade Celular , Imunidade Inata , Macaca mulatta , Masculino , Melanoma Experimental/imunologia , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Pessoa de Meia-Idade , Transdução de Sinais , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismoRESUMO
The involvement of Bregs in cancer remains poorly understood despite their well-documented regulation of responses to the self and protection from harmful autoimmunity. We recently discovered a unique regulatory B cell subset evoked by breast cancer to mediate protection of metastasizing cancer cells. These results together with the wealth of findings of the last 40 years on B cells in tumorigenesis suggest the existence of additional cancer Bregs modulating anticancer responses. To facilitate the search for them, here we provide our detailed protocol for the characterization and generation of tumor-evoked regulatory B cells. Wherever applicable, we also discuss nuances and uniqueness of a Breg study in cancer to warn potential pitfalls.
Assuntos
Linfócitos B Reguladores/imunologia , Linfócitos B Reguladores/patologia , Quimiocina CCL17/imunologia , Exotoxinas/imunologia , Neoplasias/imunologia , Neoplasias/patologia , Proteínas Recombinantes de Fusão/imunologia , Animais , Carcinogênese/imunologia , Carcinogênese/patologia , Quimiocina CCL17/genética , Quimiocina CCL17/isolamento & purificação , Cromatografia por Troca Iônica/métodos , Escherichia coli/genética , Exotoxinas/genética , Exotoxinas/isolamento & purificação , Expressão Gênica , Humanos , Imunofenotipagem/métodos , Camundongos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/isolamento & purificaçãoRESUMO
We reported previously that tumor-evoked regulatory B cells (tBregs) play an essential role in breast cancer lung metastasis by inducing TGF-ß-dependent conversion of metastasis-promoting Foxp3(+) regulatory T cells (Tregs). In this article, we show that resveratrol (RSV), a plant-derived polyphenol, at low and noncytotoxic doses for immune cells, can efficiently inhibit lung metastasis in mice. The mechanism of this process is that RSV inactivates Stat3, preventing the generation and function of tBregs, including expression of TGF-ß. As a result, it frees antitumor effector immune responses by disabling tBreg-induced conversion of Foxp3(+) Tregs. We propose that low doses of RSV may also benefit humans by controlling cancer escape-promoting tBregs/Tregs without nonspecific inactivation of effector immune cells.