RESUMEN
Senescent cells were recently shown to play a role in aging-related malfunctions and pathologies. This consensus has been facilitated by evidence from senolytic model mice capable of eliminating senescent cells in tissues using well-characterized senescent markers, such as p16INK4a (hereafter p16). However, since the incomplete or artificial gene expression regulatory regions of manipulated marker genes affect their cognate expression, it currently remains unclear whether these models accurately reflect physiological senescence. We herein describe a novel approach to eliminate p16-expressing cells from mice at any given point in time, generating a new type of knock-in model, p16hCD2 mice and a toxin-conjugated anti-human CD2 antibody (hCD2-SAP) as an inducer. p16hCD2 mice possess an intact Cdkn2a locus that includes a p16 coding region and human CD2 (hCD2) expression unit. We confirmed cognate p16-associated hCD2 expression in mouse embryonic fibroblasts (MEFs) and in several tissues, such as the spleen, liver, and skin. We detected chronological increases in the hCD2-positive population in T lymphocytes that occurred in a p16-dependent manner, which reflected physiological aging. We then confirmed the high sensitivity of hCD2-SAP to hCD2 and validated its efficacy to remove p16-positive cells, particularly in T lymphocytes. The multiple administration of hCD2-SAP for a prolonged p16-positive cell deficiency partially restored aging-related phenotypes in T lymphocytes, such as the contraction of the CD4+ naïve population and expansion of senescence-associated T cells. Our novel approach of targeting p16-positive senescent cells will provide novel insights into the mechanisms underlying physiological aging in vivo.
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Inmunotoxinas , Linfocitos T , Ratones , Animales , Senescencia Celular/fisiología , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Inmunotoxinas/genética , Inmunotoxinas/metabolismo , Senoterapéuticos , Fibroblastos/metabolismo , Fenotipo , Linfocitos T CD4-PositivosRESUMEN
BACKGROUND: Memory B cells are an antigen-experienced B-cell population with the ability to rapidly differentiate into antibody-producing cells by recall responses. We recently found that dedicator of cytokinesis 11 (DOCK11) contributes to the expansion of antigen-specific populations among germinal center B cells upon immunization. In comparison, limited information is available on the contribution of DOCK11 to secondary humoral immune responses. RESULTS: In this study, effects of the DOCK11 deficiency in B cells were examined on secondary immune responses to protein antigen. The lack of DOCK11 in B cells resulted in the impaired induction of antibody-producing cells upon secondary immunization with protein antigen. DOCK11 was dispensable for the recall responses of antigen-experienced B cells, as demonstrated by the comparable induction of antibody-producing cells in mice given transfer of antigen-experienced B cells with no DOCK11 expression. Instead, the lack of DOCK11 in B cells resulted in the impaired secondary immune responses in a B cell-extrinsic manner, which was recovered by the adoptive transfer of cognate T cells. CONCLUSIONS: We addressed that intrinsic and extrinsic effects of DOCK11 expression in B cells may contribute to secondary humoral immune responses in manner of the induction of cognate T-cell help.
RESUMEN
Aging involves age-progressive loss of physiological functions in organs and tissues. We previously showed that Lactobacillus paracasei KW3110 suppressed age-related inflammation and prevented age-related retinal ganglion cell (RGC) loss. As RGCs mediate biological behaviors associated with responses to ambient light, we assessed whether L. paracasei KW3110 affects circadian locomotor activities in physiologically aged mice. The ratio of locomotor activity during the nighttime (active phase) to daytime (inactive phase) significantly decreased in physiologically aged mice compared with young mice: intake of L. paracasei KW3110 prevented this decrease. We also performed metabolomics analysis of cecal contents using both capillary electrophoresis and liquid chromatography time-of-flight mass spectrometry to better understand the benefical effects for aging of L. paracasei KW3110 through a gut retina axis, since our previous study showed that L. paracasei KW3110 mitigated not only age-related expansions of intestinal inflammatory immune cells but age-related alternation of gut microbiome composition. Principal component analysis showed clear changes in metabolites between physiologically aged mice fed a diet containing L. paracasei KW3110 and age-matched control mice. Furthermore, we found that intake of L. paracasei KW3110 mitigated age-related changes in some fatty acids compared with age-matched control mice. Taken together, L. paracasei KW3110 might regulate age-related alternation of metabolites in cecal contents, potentially leading to suppression of age-related decline in physiological functions, including impairment of circadian locomotor activities.
Asunto(s)
Lacticaseibacillus paracasei , Probióticos , Animales , Inflamación , Locomoción , Ratones , RetinaRESUMEN
Germinal centers (GCs) are a structure in which B cell populations are clonally expanded, depending on their affinities to Ag. Although we previously isolated a characteristic protein called dedicator of cytokinesis 11 (DOCK11) from GC B cells, limited information is available on the roles of DOCK11 in GC B cells. In this study, we demonstrate that DOCK11 may contribute to the expansion of Ag-specific populations among GC B cells upon immunization of mice. The lack of DOCK11 in B cells resulted in the lower frequency of Ag-specific GC B cells along with enhanced apoptosis upon immunization. Under competitive conditions, DOCK11-deficient B cells were dramatically prevented from participating in GCs, in contrast to DOCK11-sufficient B cells. However, minor impacts of the DOCK11 deficiency were identified on somatic hypermutations. Mechanistically, the DOCK11 deficiency resulted in the suppression of B cell-intrinsic signaling in vitro and in vivo. Although DOCK11 expression by B cells was required for the induction of T follicular helper cells at the early stages of immune responses, minor impacts were identified on the expansion of Ag-specific populations among GC B cells. Thus, DOCK11 appears to contribute to the expansion of Ag-specific populations among GC B cells through the stimulation of B cell-intrinsic signaling.
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Linfocitos B/inmunología , Centro Germinal/inmunología , Factores de Intercambio de Guanina Nucleótido/deficiencia , Animales , Presentación de Antígeno , Apoptosis , Femenino , Inmunización , Masculino , Ratones , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: Vitamins and minerals are routinely administered by total parenteral nutrition (TPN). However, in Japan, adjustments in iron dosage are difficult because blended mineral preparations are often used. It is therefore unclear whether the iron content is appropriate in cases of long-term TPN. The aim of the study was to assess the influence of iron administration by long-term TPN on iron deposition in post-mortem liver samples isolated from older deceased patients. METHODS: Liver tissues were collected from post-mortem autopsies of 187 patients over a period of 15 years. Samples were stained with Prussian blue and histologically evaluated from Grade 0-V by at least three different observers. Specimens with positive and negative iron staining were compared, and positive samples were grouped according to the level and distribution of the staining. Post-mortem blood obtained from the subclavian vein during autopsy was also analysed. Samples were collected for the measurement of unsaturated serum iron, serum iron, albumin, prealbumin, hepcidin, and IL-6 concentrations. RESULTS: Iron accumulation in the liver was significantly higher in male patients (p = 0.005) with a history of surgery (p = 0.044) or central vein administration of iron (p<0.001). Additionally, the duration of TPN in the iron-positive group was significantly longer than in the iron-negative group (p = 0.038). Serum analysis revealed that unsaturated serum iron was significantly higher in the iron-negative group and that ferritin and serum iron were significantly higher in the iron-positive group. No other statistically significant differences were observed between the two groups. CONCLUSIONS: Chronic intravenous administration of iron was associated with iron deposition in the liver, even when given the minimum recommended dosage. In long-term TPN patients, the iron dose should therefore be carefully considered.
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Hierro/administración & dosificación , Hígado/metabolismo , Anciano , Anciano de 80 o más Años , Autopsia , Femenino , Humanos , Infusiones Intravenosas , Hierro/sangre , Hierro/metabolismo , Hígado/patología , Masculino , Nutrición ParenteralRESUMEN
Recently, aging is becoming an important social problem in many developed countries including Japan. It is socially and universally important to unveil the impact of aging and extend healthy life expectancy. Here we show our recent finding that dedicator of cytokinesis 11 (DOCK11, also known as Zizimin2) may be involved in immunosenescence of B cells. DOCK11 was identified as a guanine nucleotide exchange factor for a small GTPase called cell division cycle 42. Expression of DOCK11 is restricted to lymphoid tissues, and becomes downregulated with age. Thus we examined the involvement of DOCK11 in immunosenescence of B-1a B cells as an example. B-1a cells are the main source of antibodies at steady state, and function as the first line of defense against infection. Although DOCK11 was expressed by B-1a cells, the expression levels declined with age. Furthermore, production of anti-pneumococcal immunoglobulin M antibodies was suppressed in aged mice, and was recovered by adoptive transfer with B-1a cells in a DOCK11-dependent manner. Thus DOCK11 may be involved in immunosenescence of B-1a cells.
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Envejecimiento/inmunología , Inmunosenescencia , Animales , Linfocitos B/inmunología , Citocinesis/inmunología , Expresión Génica , Factores de Intercambio de Guanina Nucleótido/genética , Factores de Intercambio de Guanina Nucleótido/inmunología , Factores de Intercambio de Guanina Nucleótido/metabolismo , Humanos , Inmunoglobulina M , Ratones , Estado Nutricional , Streptococcus pneumoniae/inmunologíaRESUMEN
Inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn's disease, are chronic disorders of the gastrointestinal tract, although the exact causes of IBD remain unknown. Present treatments for IBDs have poor tolerability and insufficient therapeutic efficacy, thus, alternative therapeutic approaches are required. Soybean-derived isoflavones have multiple bioactivities such as anti-inflammation. However, the low water solubility of soybean isoflavones limits their bioavailability and practical use. Therefore, in order to study the preventive effects of water-soluble soybean isoflavones on colonic inflammatory status, we examined soybean-derived isoflavone glycosides (SIFs) in a dextran sodium sulfate (DSS)-induced murine colitis model and in lipopolysaccharide (LPS)-activated RAW264.7 macrophages. Oral administration of SIF (0.5 w/v%) attenuated DSS-induced colitis in terms of body weight decrease, colon shortening, epithelial apoptosis, histological score, mRNA levels of inflammatory cytokines, and immune cell infiltration in colon tissues. In the in vitro assessment, we observed the inhibitory effects of SIF on the production of nitric oxide and prostaglandin E2, via suppression of inducible nitric oxide synthase and cyclooxygenase-2 expression in RAW264.7 macrophages in response to LPS. Furthermore, we confirmed that the expression of inflammatory cytokines and chemokines were decreased by pre-treatment with SIF in LPS-activated RAW264.7 macrophages. Moreover, we demonstrated that SIF suppressed inflammatory mediators involved in nuclear factor-κB signaling pathway via inhibitory κB kinase phosphorylation and degradation of inhibitory κB. Our results suggested that SIF may be beneficial for the remission of colonic inflammatory status including IBDs.
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Antiinflamatorios/administración & dosificación , Colitis/prevención & control , Colon/efectos de los fármacos , Sulfato de Dextran , Glycine max , Isoflavonas/administración & dosificación , Lipopolisacáridos/farmacología , Activación de Macrófagos/efectos de los fármacos , Macrófagos/efectos de los fármacos , Animales , Antiinflamatorios/aislamiento & purificación , Colitis/inducido químicamente , Colitis/inmunología , Colitis/patología , Colon/inmunología , Colon/metabolismo , Colon/patología , Citocinas/metabolismo , Modelos Animales de Enfermedad , Mediadores de Inflamación/metabolismo , Isoflavonas/aislamiento & purificación , Macrófagos/inmunología , Macrófagos/metabolismo , Masculino , Ratones , Células RAW 264.7 , Inducción de Remisión , Transducción de Señal , Glycine max/químicaRESUMEN
The major hallmarks of Alzheimer's disease (AD) are the extracellular accumulation of pathological amyloid beta (Aß) in the brain parenchyma and Aß deposition in cerebral blood walls (cerebral amyloid angiopathy; CAA). Although CAA occurs in more than 80% of AD patients, the mechanisms of Aß deposition and clearance around the vessel walls are unknown. We found Aß-degrading activity in human serum during analysis of the regulatory mechanism of Aß production in human endothelial cells. To elucidate the metabolic dynamics of Aß surrounding the brain microvessels, we identified Aß-degrading activity in human serum (blood Aß-degrading activity: BADA) by column chromatography and LC/MS. BADA exhibited characteristics of an acidic protein, pI 4.3, which had two different protein surface charges (low and high affinity cations). Both BADA fractions had a relative molecular mass of greater than 400 kDa. Furthermore, BADA in the low affinity cation fraction was inhibited by the serine protease inhibitor 4-(2-Aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF). We clarified alpha-2-macroglobulin (a2M) and several serine proteases from this BADA by LC-MS. Moreover, we demonstrated that BADA is increased by approximately 5000-fold in human serum by column chromatography. Therefore, BADA may play an important role in the circulation and metabolism of Aß in human brain microvessels.
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Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Encéfalo/irrigación sanguínea , Encéfalo/patología , Encéfalo/fisiología , Angiopatía Amiloide Cerebral/patología , Cromatografía Liquida , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Macroglobulinas/metabolismo , Espectrometría de Masas , Microvasos/patología , Microvasos/fisiología , Serina Proteasas/metabolismoRESUMEN
AIM: Skin aging is caused by intrinsic and extrinsic mechanisms. Because it is difficult to distinguish intrinsic mechanisms from extrinsic skin aging, the mechanisms of intrinsic skin aging remain unclear. The present study aimed to characterize age-associated alterations in murine skin and investigate the mechanisms of intrinsic skin aging. METHODS: We measured morphological changes in dorsal skin from young (aged 2 months) and old (aged 22-24 months) mice by histological analysis. Age-associated alteration of gene expression patterns was determined by quantitative polymerase chain reaction and immunohistochemistry. Reactive oxygen species production in mouse dorsal skin was detected by confocal laser scanning microscopy. Mitochondrial DNA deletions were detected by conventional polymerase chain reaction and quantitative polymerase chain reaction analyses. RESULTS: Chronologically aged skin had dermal atrophy caused by increased matrix-degrading enzymes and decreased collagen synthesis. Chronologically aged skin samples also had increased senescence-associated secretory phenotype factors, elevated reactive oxygen species production and a higher frequency of the mitochondrial DNA common deletion. CONCLUSIONS: These observations suggest that chronological skin aging is associated with increased frequency of the mitochondrial DNA common deletion and chronic inflammation through the reactive oxygen species-senescence-associated secretory phenotype axis. Geriatr Gerontol Int 2019; 19: 451-457.
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Senescencia Celular/fisiología , Colágeno/metabolismo , ADN Mitocondrial/análisis , Especies Reactivas de Oxígeno/análisis , Envejecimiento de la Piel/fisiología , Animales , Células Cultivadas , Perfilación de la Expresión Génica , Inflamación , Ratones , Fenómenos Fisiológicos de la PielRESUMEN
OBJECTIVES: Mucins are heavily glycosylated large glycoproteins produced in the salivary glands that contribute to salivary viscosity. This study aimed to characterize age-related changes in mucin production in mouse submandibular salivary gland (SMG). METHODS: The paraffin sections of the SMGs of the young and aged mice were stained with HE or Alcian blue (AB). SMGs mucins derived from the young and aged mice were separated using supported molecular matrix electrophoresis (SMME). After SMME, the membranes were stained with AB and subsequent glycan analysis or subjected to immunoblotting. The expression of 18 mucin genes and 4 sialyltransferase genes in the young and aged SMGs were determined by qPCR. The neuraminidase activity in the SMG homogenates was determined using Neuraminidase Assay Kit. RESULTS: The mouse SMG is more strongly stained by AB with increasing age. On SMME, a characteristic band not found in the young SMG is detected in aged SMG. Based on migration position and the MALDI MS, the band that appeared specifically with aging was determined to be acidic mucin. Additionally, most glycans of this acidic mucin were sialo-oligosaccharides. Furthermore, there was an increase in the expression of sialyltransferase genes ST6GalNAc I and ST6GalNAc II, but not a decrease in neuraminidase activity, in the SMG of aged mice. CONCLUSION: A sialomucin or sialylated mucin-like molecule not found in the SMGs of young WT mice is expressed in aged WT mice. The increase in the sialo-oligosaccharide content in this aging-associated molecule may be attributed to the increased expression of the sialyltransferase genes.
Asunto(s)
Mucinas/metabolismo , Oligosacáridos/metabolismo , Sialiltransferasas/metabolismo , Glándula Submandibular/metabolismo , Factores de Edad , Animales , Expresión Génica , Immunoblotting , Ratones , Ratones Endogámicos C57BL , Mucinas/genética , Neuraminidasa/genética , Neuraminidasa/metabolismo , Oligosacáridos/genética , Reacción en Cadena de la Polimerasa , Polisacáridos/genética , Polisacáridos/metabolismo , Sialiltransferasas/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
Age-related chronic inflammation is a major risk factor for the incidence and prevalence of age-related diseases, including infectious and neurodegenerative diseases. We previously reported that a lactic acid bacteria, Lactobacillus paracasei KW3110, activated macrophages and suppressed inflammation in mice and humans. In this study, we investigated whether long-term intake of heat-killed L. paracasei KW3110 modulated age-related inflammation and altered the gut microbiota in physiologically aged mice. Compared with age-matched control mice, fecal analyses of gut microbiota revealed that intake of L. paracasei KW3110 mitigated age-related changes of beneficial bacterial composition, including the Bifidobacteriaceae family. L. paracasei KW3110 intake also mitigated age-related immune defects by reducing the prevalence of interferon-gamma (IFN-γ) -producing inflammatory CD4-positive T cells in the lamina propia of the small intestine, and reduced serum levels of proinflammatory cytokines. Furthermore, L. paracasei KW3110 intake suppressed retinal inflammation by reducing proinflammatory cytokine-producing macrophage, and age-related retinal cell loss. Taken together, these findings suggested that L. paracasei KW3110 mitigated age-related chronic inflammation through modulation of gut microbiota composition and immune system functions in aged mice, and also reduced age-related retinal ganglion cell (RGC) loss. Further studies are needed to evaluate the effect in age-related senescent changes of the retina.
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Microbioma Gastrointestinal , Envejecimiento Saludable , Inflamación/prevención & control , Lacticaseibacillus paracasei/crecimiento & desarrollo , Probióticos/administración & dosificación , Retina/microbiología , Degeneración Retiniana/prevención & control , Factores de Edad , Animales , Citocinas/inmunología , Femenino , Interacciones Huésped-Patógeno , Inflamación/inmunología , Inflamación/microbiología , Mediadores de Inflamación/inmunología , Lacticaseibacillus paracasei/inmunología , Subgrupos Linfocitarios/inmunología , Subgrupos Linfocitarios/microbiología , Activación de Macrófagos , Macrófagos/inmunología , Macrófagos/microbiología , Ratones Endogámicos C57BL , Retina/inmunología , Retina/patología , Degeneración Retiniana/inmunología , Degeneración Retiniana/microbiología , Degeneración Retiniana/patología , Factores de TiempoRESUMEN
Zizimin2 (Ziz2), also known as dedicator of cytokinesis 11 (DOCK11), is a guanine nucleotide exchange factor that is predominantly expressed in lymphoid tissues. Recent findings demonstrated that Ziz2 is involved in the development of B cells, including germinal centre B cells and marginal zone B cells. However, limited information is currently available on the roles of Ziz2 in B-1 cells, a B-cell subset that resides in body cavities and contributes to protection against foreign pathogens in a T-cell-independent manner. We herein show that Ziz2 and its widely expressed isoform Ziz3 (also known as DOCK10) may be involved in defective production of anti-bacterial IgM by aged B-1a cells, a CD5+ subset of B-1 cells. Natural IgM against typical bacterial epitopes was defectively produced by peritoneal B-1a cells from aged mice. The down-regulation of Ziz2/3 in B-1a cells appeared to be responsible for this defective IgM production, as demonstrated by Ziz2/3 double-knockout mice. Mechanistically, lower levels of basal AKT phosphorylation did not allow for the differentiation of Ziz2/3-deficient B-1a cells into plasma cells. Defective production of anti-bacterial IgM was not fully rescued by immunization, resulting in slightly weaker protection in Ziz2/3-deficient mice. Thus, the down-regulation of Ziz2/3 in B-1a cells may at least partly account for defective protection in aged mice.
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Envejecimiento/inmunología , Subgrupos de Linfocitos B/inmunología , Linfocitos B/inmunología , Factores de Intercambio de Guanina Nucleótido/genética , Animales , Anticuerpos Antibacterianos/metabolismo , Antígenos CD5/metabolismo , Diferenciación Celular/genética , Células Cultivadas , Factores de Intercambio de Guanina Nucleótido/metabolismo , Inmunoglobulina M/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Cavidad Peritoneal/citologíaRESUMEN
Senescent cells accumulate in many tissues as animals age and are considered to underlie several aging-associated pathologies. The tumor suppressors p19ARF and p16INK4a, both of which are encoded in the CDKN2A locus, play critical roles in inducing and maintaining permanent cell cycle arrest during cellular senescence. Although the elimination of p16INK4a-expressing cells extends the life span of the mouse, it is unclear whether tissue function is restored by the elimination of senescent cells in aged animals and whether and how p19ARF contributes to tissue aging. The aging-associated decline in lung function is characterized by an increase in compliance as well as pathogenic susceptibility to pulmonary diseases. We herein demonstrated that pulmonary function in 12-month-old mice was reversibly restored by the elimination of p19ARF-expressing cells. The ablation of p19ARF-expressing cells using a toxin receptor-mediated cell knockout system ameliorated aging-associated lung hypofunction. Furthermore, the aging-associated gene expression profile was reversed after the elimination of p19ARF. Our results indicate that the aging-associated decline in lung function was, at least partly, attributed to p19ARF and was recovered by eliminating p19ARF-expressing cells.
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Envejecimiento , Senescencia Celular/genética , Pulmón/fisiología , Proteína p14ARF Supresora de Tumor/genética , Animales , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Pruebas de Función RespiratoriaRESUMEN
Increasing evidence indicates that defects in the sensory system are highly correlated with age-related neurodegenerative diseases, including Alzheimer's disease (AD). This raises the possibility that sensory cells possess some commonalities with neurons and may provide a tool for studying AD. The sensory system, especially the auditory system, has the advantage that depression in function over time can easily be measured with electrophysiological methods. To establish a new mouse AD model that takes advantage of this benefit, we produced transgenic mice expressing amyloid-ß (Aß), a causative element for AD, in their auditory hair cells. Electrophysiological assessment indicated that these mice had hearing impairment, specifically in high-frequency sound perception (>32 kHz), at 4 months after birth. Furthermore, loss of hair cells in the basal region of the cochlea, which is known to be associated with age-related hearing loss, appeared to be involved in this hearing defect. Interestingly, overexpression of human microtubule-associated protein tau, another factor in AD development, synergistically enhanced the Aß-induced hearing defects. These results suggest that our new system reflects some, if not all, aspects of AD progression and, therefore, could complement the traditional AD mouse model to monitor Aß-induced neuronal dysfunction quantitatively over time.
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Enfermedad de Alzheimer/complicaciones , Péptidos beta-Amiloides/metabolismo , Modelos Animales de Enfermedad , Células Ciliadas Auditivas/metabolismo , Pérdida Auditiva de Alta Frecuencia/etiología , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Animales , Femenino , Células Ciliadas Auditivas/patología , Pérdida Auditiva de Alta Frecuencia/metabolismo , Pérdida Auditiva de Alta Frecuencia/patología , Masculino , Ratones Transgénicos , Proteínas tau/metabolismoRESUMEN
CD40 ligand is induced in CD4(+) Th cells upon TCR stimulation and provides an activating signal to B cells, making CD40 ligand an important molecule for Th cell function. However, the detailed molecular mechanisms, whereby CD40 ligand becomes expressed on the cell surface in T cells remain unclear. Here, we showed that CD40 ligand expression in CD8(+) cytotoxic T cells was suppressed by combined epigenetic regulations in the promoter region of the Cd40lg gene, such as the methylation of CpG dinucleotides, histone H3 lysine 9, histone H3 lysine 27, and histone H4 lysine 20. As the transcription factor Th-inducing pox virus and zinc finger/Kruppel-like factor (encoded by the Zbtb7b gene) is critical in Th cell development, we focused on the role of Th-inducing pox virus and zinc finger/Kruppel-like factor in CD40 ligand expression. We found that CD40 ligand expression is moderately induced by retroviral Thpok transduction into CD8(+) cytotoxic T cells, which was accompanied by a reduction of histone H3 lysine 9 methylation and histone H3 lysine 27 methylation in the promoter region of the Cd40lg gene. Th-inducing pox virus and zinc finger/Kruppel-like factor directly inhibited the expression of murine CXXC5, a CXXC-type zinc finger protein that induced histone H3 lysine 9 methylation, in part, through an interaction with the histone-lysine N-methyltransferase SUV39H1. In addition, to inhibit CD40 ligand induction in activated CD4(+) T cells by the CXXC5 transgene, our findings indicate that CXXC5 was one of the key molecules contributing to repressing CD40 ligand expression in CD8(+) cytotoxic T cells.
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Ligando de CD40/antagonistas & inhibidores , Linfocitos T CD8-positivos/inmunología , Metilación de ADN , Histonas/genética , Péptidos y Proteínas de Señalización Intracelular/fisiología , Metiltransferasas/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Represoras/metabolismo , Factores de Transcripción/fisiología , Acetilación , Animales , Ligando de CD40/metabolismo , Proteínas de Unión al ADN , Regulación de la Expresión Génica , Silenciador del Gen , N-Metiltransferasa de Histona-Lisina , Lisina/genética , Masculino , Metiltransferasas/genética , Ratones , Ratones Noqueados , Regiones Promotoras Genéticas/genética , Proteínas Represoras/genética , Linfocitos T Citotóxicos/inmunologíaRESUMEN
AIM: We investigated the effect of prebiotics on the immunological response after influenza vaccination in enterally fed elderly individuals. The intervention group was given an enteral formula containing lactic acid bacteria-fermented milk products. In addition, two different types of other prebiotics, galacto-oligosaccharide and bifidogenic growth stimulator, were also given. The two prebiotics improved intestinal microbiota differently. In a control group, a standard formula without prebiotics was given. METHODS: An enteral formula with (intervention group [F]) or without (control group [C]) prebiotics was given through percutaneous endoscopic gastrostomy to elderly participants for 10 weeks. Influenza vaccine was inoculated at week 4. Nutritional and biochemical indices, intestinal micro bacteria and immunological indices were analyzed. RESULTS: The Bifidobacterium count in groups F and C at week 0 was 6.4 ± 1.9 and 6.6 ± 3.0 (log10 [count/g feces]), respectively. Although the count in group C decreased at week 10, the count in group F increased. The Bacteroides count in group F increased from 10.7 ± 0.9 to 11.4 ± 0.5, but decreased in group C from 11.2 ± 0.2 to 10.7 ± 0.4. Although the enhanced titers of H1N1, H3N2 and B antigens against the vaccine decreased thereafter in group C, these enhanced titers in group F could be maintained. CONCLUSION: Our findings suggest that prebiotics affect the intestinal microbiota and might maintain the antibody titers in elderly individuals.
Asunto(s)
Nutrición Enteral , Vacunas contra la Influenza , Gripe Humana/prevención & control , Prebióticos , Vacunación , Anciano , Anciano de 80 o más Años , Femenino , Humanos , MasculinoRESUMEN
We investigated the effect of a formula containing two different prebiotics (bifidogenic growth stimulator and galacto-oligosaccharide) and fermented milk products on intestinal microbiota and antibody responses to an influenza vaccine in enterally fed elderly in-patients. Patients were administered either formula containing prebiotics and fermented milk products (group F: n = 12, 79.9 ± 9.5 years old) or standard formula (group C: n = 12, 80.7 ± 10.1 years old) via percutaneous endoscopic gastrostomy during a 14-week intervention period. Subjects were immunized with an influenza vaccine (A/H1N1, A/H3N2, and B) at week 4 of the intervention. Blood biochemical indices, intestinal bacteria populations and antibody titers were analyzed. Bifidobacterium counts increased significantly in group F compared with group C. The enhanced antibody titers against A/H1N1 were maintained in group F for a longer period compared with group C. The titers against A/H3N2 were unchanged between both groups, and those against B were significantly lower in group F than in group C, although few subjects had seroprotective titers against A/H3N2 and B. These results suggest that administration of the formula containing prebiotics and fermented milk products may maintain antibody titers for longer periods through the improvement of intestinal microbiota.
RESUMEN
Bmi-1 prevents stem cell aging, at least partly, by blocking expression of the cyclin-dependent kinase inhibitor p16(Ink4a) . Therefore, dysregulation of the Bmi-1/p16(Ink4a) pathway is considered key to the loss of tissue homeostasis and development of associated degenerative diseases during aging. However, because Bmi-1 knockout (KO) mice die within 20 weeks after birth, it is difficult to determine exactly where and when dysregulation of the Bmi-1/p16(Ink4a) pathway occurs during aging in vivo. Using real-time in vivo imaging of p16(Ink4a) expression in Bmi-1-KO mice, we uncovered a novel function of the Bmi-1/p16(Ink4a) pathway in controlling homeostasis of the submandibular glands (SMGs), which secrete saliva into the oral cavity. This pathway is dysregulated during aging in vivo, leading to induction of p16(Ink4a) expression and subsequent declined SMG function. These findings will advance our understanding of the molecular mechanisms underlying the aging-related decline of SMG function and associated salivary gland hypofunction, which is particularly problematic among the elderly.
Asunto(s)
Envejecimiento/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Complejo Represivo Polycomb 1/genética , Proteínas Proto-Oncogénicas/genética , Glándula Submandibular/metabolismo , Células Madre Adultas/citología , Células Madre Adultas/metabolismo , Envejecimiento/patología , Animales , Diferenciación Celular , Proliferación Celular , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Femenino , Regulación de la Expresión Génica , Genes Reporteros , Homeostasis , Luciferasas/genética , Luciferasas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Complejo Represivo Polycomb 1/deficiencia , Proteínas Proto-Oncogénicas/deficiencia , Saliva/metabolismo , Transducción de Señal , Glándula Submandibular/patologíaRESUMEN
We originally cloned and identified murine Zizimin2 (Ziz2, Dock11) as a guanine nucleotide exchange factor (GEF) for Cdc42 and demonstrated that it activated the formation of filopodia. Since its expression pattern is restricted in immune tissues and Rho GTPases such as Cdc42 function in B cell development and immune responses, we expected Ziz2 to also be associated with B cell development and immune responses. However, the function of Ziz2 has not yet been fully examined in vivo. We also recently discovered that Ziz2 expression levels in immune tissues were reduced with aging in the mouse, suggesting that its expression is also associated with the mechanisms of immuno-senescence. To gain insights into the mechanisms underlying immuno-senescence, we generated Ziz2 knock out (KO) mice and examined the functions of Ziz2 in B cell development and immune responses. We also obtained Zizimin3 (Ziz3; Dock10) KO mice and examined the functions of Ziz3. The results revealed that Ziz2 KO mice had a higher percentage of early bone marrow B cells (Fraction A), but a reduced fraction of marginal zone (MZ) B cells. In addition, an examination of B cell-specific Ziz2 KO mice revealed that Ziz2 was intrinsically required for MZ B cell development, but not for mature follicular B cells. However, immune responses against NP-CGG (T cell-dependent), TNP-LPS (T cell-independent, TI, type I), and TNP-Ficoll (TI, type II) were not altered in KO mice. We finally demonstrated that CD1d-positive MZ B cell region outside CD169-positive marginal metallophilic macrophages (MMM) was narrowed in Ziz2 KO mice. Furthermore, MMM morphology appeared to be altered in Ziz2 KO mice. In conclusion, we herein showed that Ziz2 was associated with early bone marrow B cell development, MZ B cell formation, MZ B number/localization around MZ, and MMM morphology which may explain in part the mechanism underlying immuno-senescence.
RESUMEN
Senescent cells develop a pro-inflammatory response termed the senescence-associated secretory phenotype (SASP). As many SASP components affect surrounding cells and alter their microenvironment, SASP may be a key phenomenon in linking cellular senesence with individual aging and age-related diseases. We herein demonstrated that the expression of Sirtuin1 (SIRT1) was decreased and the expression of SASP components was reciprocally increased during cellular senescence. The mRNAs and proteins of SASP components, such as IL-6 and IL-8, quickly accumulated in SIRT1-depleted cells, and the levels of these factors were also higher than those in control cells, indicating that SIRT1 negatively regulated the expression of SASP factors at the transcriptional level. SIRT1 bound to the promoter regions of IL-8 and IL-6, but dissociated from them during cellular senescence. The acetylation of Histone H3 (K9) and H4 (K16) of the IL-8 and IL-6 promoter regions gradually increased during cellular senescence. In SIRT1-depleted cells, the acetylation levels of these regions were already higher than those in control cells in the pre-senescent stage. Moreover, these acetylation levels in SIRT1-depleted cells were significantly higher than those in control cells during cellular senescence. These results suggest that SIRT1 repressed the expression of SASP factors through the deacetylation of histones in their promoter regions.