Altered regulation of cytosolic Ca2+ concentration in dendritic cells from klotho hypomorphic mice

2013 ◽  
Vol 305 (1) ◽  
pp. C70-C77 ◽  
Author(s):  
Ekaterina Shumilina ◽  
Meerim K. Nurbaeva ◽  
Wenting Yang ◽  
Evi Schmid ◽  
Kalina Szteyn ◽  
...  

The function of dendritic cells (DCs), antigen-presenting cells regulating naïve T-cells, is regulated by cytosolic Ca2+ concentration ([Ca2+]i). [Ca2+]i is increased by store-operated Ca2+ entry and decreased by K+-independent (NCX) and K+-dependent (NCKX) Na+/Ca2+ exchangers. NCKX exchangers are stimulated by immunosuppressive 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], the biologically active form of vitamin D. Formation of 1,25(OH)2D3 is inhibited by the antiaging protein Klotho. Thus 1,25(OH)2D3 plasma levels are excessive in Klotho-deficient mice ( klotho hm). The present study explored whether Klotho deficiency modifies [Ca2+]i regulation in DCs. DCs were isolated from the bone marrow of klotho hm mice and wild-type mice ( klotho+/+) and cultured for 7–9 days with granulocyte-macrophage colony-stimulating factor. According to major histocompatibility complex II (MHC II) and CD86 expression, differentiation and lipopolysaccharide (LPS)-induced maturation were similar in klotho hm DCs and klotho+/+ DCs. However, NCKX1 membrane abundance and NCX/NCKX-activity were significantly enhanced in klotho hm DCs. The [Ca2+]i increase upon acute application of LPS (1 μg/ml) was significantly lower in klotho hm DCs than in klotho+/+ DCs, a difference reversed by the NCKX blocker 3′,4′-dichlorobenzamyl (DBZ; 10 μM). CCL21-dependent migration was significantly less in klotho hm DCs than in klotho+/+ DCs but could be restored by DBZ. NCKX activity was enhanced by pretreatment of klotho+/+ DC precursors with 1,25(OH)2D3 the first 2 days after isolation from bone marrow. Feeding klotho hm mice a vitamin D-deficient diet decreased NCKX activity, augmented LPS-induced increase of [Ca2+]i, and enhanced migration of klotho hm DCs, thus dissipating the differences between klotho hm DCs and klotho+/+ DCs. In conclusion, Klotho deficiency upregulates NCKX1 membrane abundance and Na+/Ca2+-exchange activity, thus blunting the increase of [Ca2+]i following LPS exposure and CCL21-mediated migration. The effects are in large part due to excessive 1,25(OH)2D3 formation.

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1355
Author(s):  
Eunike Velleuer ◽  
Carsten Carlberg

Fanconi anemia (FA) is a rare disorder with the clinical characteristics of (i) specific malformations at birth, (ii) progressive bone marrow failure already during early childhood and (iii) dramatically increased risk of developing cancer in early age, such as acute myeloid leukemia and squamous cell carcinoma. Patients with FA show DNA fragility due to a defect in the DNA repair machinery based on predominately recessive mutations in 23 genes. Interestingly, patients originating from the same family and sharing an identical mutation, frequently show significant differences in their clinical presentation. This implies that epigenetics plays an important role in the manifestation of the disease. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 controls cellular growth, differentiation and apoptosis via the modulation of the immune system. The nuclear hormone activates the transcription factor vitamin D receptor that affects, via fine-tuning of the epigenome, the transcription of >1000 human genes. In this review, we discuss that changes in the epigenome, in particular in immune cells, may be central for the clinical manifestation of FA. These epigenetic changes can be modulated by vitamin D suggesting that the individual FA patient’s vitamin D status and responsiveness are of critical importance for disease progression.


2020 ◽  
Vol 21 (5) ◽  
pp. 1890
Author(s):  
Makoto Kubo ◽  
Ryuichi Nagashima ◽  
Mitsue Kurihara ◽  
Fumitaka Kawakami ◽  
Tatsunori Maekawa ◽  
...  

Leucine-rich repeat kinase 2 (LRRK2) is the causal molecule of familial Parkinson’s disease. Although the characteristics of LRRK2 have gradually been revealed, its true physiological functions remain unknown. LRRK2 is highly expressed in immune cells such as B2 cells and macrophages, suggesting that it plays important roles in the immune system. In the present study, we investigate the roles of LRRK2 in the immune functions of dendritic cells (DCs). Bone marrow-derived DCs from both C57BL/6 wild-type (WT) and LRRK2 knockout (KO) mice were induced by culture with granulocyte/macrophage-colony stimulating factor (GM/CSF) in vitro. We observed the differentiation of DCs, the phosphorylation of the transcriptional factors NF-κB, Erk1/2, and p-38 after lipopolysaccharide (LPS) stimulation and antigen-presenting ability by flow cytometry. We also analyzed the production of inflammatory cytokines by ELISA. During the observation period, there was no difference in DC differentiation between WT and LRRK2-KO mice. After LPS stimulation, phosphorylation of NF-κB was significantly increased in DCs from the KO mice. Large amounts of inflammatory cytokines were produced by DCs from KO mice after both stimulation with LPS and infection with Leishmania. CD4+ T-cells isolated from antigen-immunized mice proliferated to a significantly greater degree upon coculture with antigen-stimulated DCs from KO mice than upon coculture with DCs from WT mice. These results suggest that LRRK2 may play important roles in signal transduction and antigen presentation by DCs.


2006 ◽  
Vol 52 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Ziad H Al-oanzi ◽  
Stephen P Tuck ◽  
Nicholas Raj ◽  
John S Harrop ◽  
Gregory D Summers ◽  
...  

Abstract Background: Clinical assessment of vitamin D status often relies on measuring total circulating 25-hydroxyvitamin D3 (25OHD3), but much of each vitamin D metabolite is bound to plasma vitamin D–binding protein (DBP), such that the percentage of free vitamin is very low. We hypothesized that measurement of free rather than total 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and 25OHD3 may provide better assessment of vitamin D status. We therefore aimed to assess vitamin D status in men with idiopathic osteoporosis, in whom possible secondary causes of osteoporosis had been excluded, and to determine the extent of change in biologically active “free” vitamin D caused by variation in plasma DBP concentrations. Methods: We measured 1,25(OH)2D3 and 25OHD3 in plasma samples from 56 men with idiopathic osteoporosis [mean (SD) age, 59.6 (13.6) years; range, 21–86 years] and 114 male controls [62.4 (10.4) years; range, 44–82 years]. Results: Mean total plasma 25OHD3 in the 56 men with osteoporosis and the 114 controls was 44.7 (21) and 43.3 (17) nmol/L, respectively; total plasma 1,25(OH)2D3 measured in randomly selected men with osteoporosis (n = 50) and controls (n = 50) was 90 (37) and 103 (39) pmol/L, respectively. Mean plasma DBP was significantly higher (P <0.001) in men with osteoporosis [224 (62) mg/L; n = 56] than in the controls [143 (34) mg/L; n = 114], but calculated free plasma 25OHD3 and 1,25(OH)2D3 were significantly lower in the osteoporotic men than in controls [6.1 (3.1) vs 9.1 (4.4) pmol/L (P <0.00001) and 77 (37) vs 142 (58) fmol/L (P <0.00001), respectively]. Conclusions: Measurement of total vitamin D metabolites alone, although providing a crude assessment of vitamin D status, may not give an accurate indication of the free (biologically active) form of the vitamin. The ratio of total 25OHD3 and 1,25(OH)2D3 to plasma DBP, rather than total circulating vitamin D metabolites, may provide a more useful index of biological activity. Further studies are required to substantiate this hypothesis.


1990 ◽  
Vol 1 (1) ◽  
pp. 30-42
Author(s):  
R Kumar

Vitamin D3 undergoes sequential hydroxylations in the liver and kidney to form 1,25-dihydroxyvitamin D3, the biologically active form of the vitamin. 1,25-dihydroxyvitamin D3 is metabolized by several processes in various target tissues that decrease the biological activity of the sterol. In addition, 1,25-dihydroxyvitamin D3 is excreted in the bile as polar metabolites, such as glucuronides and, possibly sulfates and neutral polar steroids. These compounds undergo an enterohepatic recirculation in both man and experimental animals. 1,25-dihydroxyvitamin D3 increases the absorption of calcium in the intestine and the reabsorption of calcium in the kidney. It induces the synthesis of several proteins, the most notable of which is calcium binding protein that is thought to play a role in the absorption of calcium. The vitamin D-dependent calcium binding proteins and the calcium-magnesium ATPase calcium pump are co-localized in several tissues that play a role in the absorption of calcium.


2010 ◽  
Vol 78 (7) ◽  
pp. 2956-2965 ◽  
Author(s):  
Marlena M. Westcott ◽  
Curtis J. Henry ◽  
Jacqueline E. Amis ◽  
Elizabeth M. Hiltbold

ABSTRACT Dendritic cells (DC) provide a suboptimal niche for the growth of Listeria monocytogenes, a facultative intracellular bacterial pathogen of immunocompromised and pregnant hosts. This is due in part to a failure of large numbers of bacteria to escape to the cytosol, an essential step in the intracellular life cycle that is mediated by listeriolysin O (LLO). Here, we demonstrate that wild-type bacteria that failed to enter the cytosol of bone marrow-derived DC were retained in a LAMP2+ compartment. An isogenic L. monocytogenes strain that produces an LLO protein with reduced pore-forming activity had a severe escape and growth phenotype in DC. Few mutant bacteria entered the cytosol in the first 2 h and were instead found in LAMP2+, major histocompatibility complex class II+ (MHC-II+) H2-DM vesicles characteristic of MHC-II antigen loading compartments (MIIC). In contrast, the mutant had a minor phenotype in bone marrow-derived macrophages (BMM) despite the reduced LLO activity. In the first hour, DC phagosomes acidified to a pH that was, on average, half a point higher than that of BMM phagosomes. Unlike BMM, L. monocytogenes growth in DC was minimal after 5 h, and consequently, DC remained viable and matured late in infection. Taken together, the data are consistent with a model in which phagosomal maturation events associated with the acquisition of MHC-II molecules present a suboptimal environment for L. monocytogenes escape to the DC cytosol, possibly by limiting the activity of LLO. This, in combination with an undefined mechanism that controls bacterial growth late in infection, promotes DC survival during the critical maturation response.


Blood ◽  
2008 ◽  
Vol 112 (7) ◽  
pp. 2878-2885 ◽  
Author(s):  
Kavita M. Dhodapkar ◽  
Scott Barbuto ◽  
Phillip Matthews ◽  
Anjli Kukreja ◽  
Amitabha Mazumder ◽  
...  

Abstract IL17-producing (Th17) cells are a distinct lineage of T helper cells that regulate immunity and inflammation. The role of antigen-presenting cells in the induction of Th17 cells in humans remains to be fully defined. Here, we show that human dendritic cells (DCs) are efficient inducers of Th17 cells in culture, including antigen-specific Th17 cells. Although most freshly isolated circulating human Th17 cells secrete IL17 alone or with IL2, those induced by DCs are polyfunctional and coexpress IL17 and IFNγ (Th17-1 cells). The capacity of DCs to expand Th17-1 cells is enhanced upon DC maturation, and mature DCs are superior to monocytes for the expansion of autologous Th17 cells. In myeloma, where tumors are infiltrated by DCs, Th17 cells are enriched in the bone marrow relative to circulation. Bone marrow from patients with myeloma contains a higher proportion of Th17-1 cells compared with the marrow in preneoplastic gammopathy (monoclonal gammopathy of undetermined significance [MGUS]). Uptake of apoptotic but not necrotic myeloma tumor cells by DCs leads to enhanced induction of Th17-1 cells. These data demonstrate the capacity of DCs to induce expansion of polyfunctional IL17-producing T cells in humans, and suggest a role for DCs in the enrichment of Th17-1 cells in the tumor bed.


Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Patricio A Araos ◽  
Andrés Guzmán ◽  
Stefanny M Figueroa ◽  
Javier Reyes ◽  
Cristián A Amador

Immune cells play a major role in the development and progression of hypertension. Previous studies have shown that antigen presenting cells (APCs), such as macrophages (Mø) and dendritic cells (DCs) are particularly abundant in kidney. However, the relevance of these renal APCs on hypertension and whether their distribution change during the anti-hypertensive treatment remain unknow. We evaluated whether losartan (Los) treatment changes the abundance of APCs in the renal cortex and medulla in Angiotensin (Ang) II-infused mice.Male C57BL/6 mice (8-12wo) were treated with AngII (490ng/Kg/min), AngII+Los (20mg/Kg/day) or Vehicle for 14 days (n=4-6). Systolic blood pressure (SBP) was measured by the tail cuff method, and renal cortex/medulla were isolated for the measurements of: APCs (MHC-II + :CD11c + ), DCs (APCs:F4/80 - :CD64 - /CD103 + for type-1 DCs, or APCs:F4/80 - :CD64 - :CD11b + for type-2 DCs), and M1-like Mø (APCs:F4/80 - :CD64 + :CD11b + ), by flow cytometry.Los treatment prevented the increased SBP (AngII+Los=118.8±6.4 mmHg vs. AngII=158.0±21.1 mmHg; p<0.001), and the APCs recruitment in renal cortex (AngII+Los=23.2±2.7 vs. AngII=36.0±5.9%; p<0.01) and in renal medulla (Veh=16.3±7.7; AngII=26.3±4,7; AngII+Los=14.9±3.3%; p<0.05) induced by AngII. In addition, we observed an increase of DC2 and M1-like Mø recruitments in renal medulla of AngII mice (DC2 Veh =29.0±5.0 vs. DC2 AngII =45.5±7.3%; p<0.05; M1 Veh =44.8±7.5 vs. M1 AngII =58.3±5.3%; p<0.05), which were prevented by Los treatment (DC2 AngII+Los =27.1±6.8%; p<0.05; M1 AngII+Los =47.0±3.5%; p<0.05). Interestingly, we did not observe differences between groups on M1-like Mø, and DC2 populations in renal cortex. However, Los treatment prevented the increase of DC1 on renal cortex (Veh=2.1±1.4; AngII=5.2±2.4; AngII+Los=2.1±0.8%; p<0.05), without differences between groups at medullar level.Our results show that Los treatment has a differential effect on the APCs populations in renal cortex and medulla, suggesting that renal APCs have different participations on hypertension according their microenvironment.Supported by Fondecyt #1201251 and #3201016


Blood ◽  
2000 ◽  
Vol 95 (9) ◽  
pp. 2875-2882 ◽  
Author(s):  
Janne Komi ◽  
Olli Lassila

Dendritic cells (DC) are professional antigen-presenting cells with a unique capacity to initiate and regulate immune responses. Immature CD1a+ DC can be cultured from CD14+monocytes in the presence of interleukin (IL)-4 and granulocyte macrophage colony-stimulating factor in vitro. Results of this study show that the nonsteroidal anti-estrogens toremifene and tamoxifen inhibit this differentiation. In the presence of anti-estrogens the cells lose CD14 expression, but remain CD1a− and clearly have less dendritic processes than immature DC. Functionally, anti-estrogen-treated cells are inferior to immature DC in inducing proliferation of allogeneic T cells and in producing IL-12 p70 protein after CD40 ligation. The expression of the costimulatory molecules CD80 and CD86 is differentially regulated by anti-estrogens during DC differentiation. Furthermore, anti-estrogens are also able to inhibit the terminal maturation of DC. By inhibiting the functional differentiation of DC, anti-estrogens may have a role in the treatment and prevention of autoimmune diseases.


Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1140 ◽  
Author(s):  
Oona Koivisto ◽  
Andrea Hanel ◽  
Carsten Carlberg

The biologically active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), modulates innate and adaptive immunity via genes regulated by the transcription factor vitamin D receptor (VDR). In order to identify the key vitamin D target genes involved in these processes, transcriptome-wide datasets were compared, which were obtained from a human monocytic cell line (THP-1) and peripheral blood mononuclear cells (PBMCs) treated in vitro by 1,25(OH)2D3, filtered using different approaches, as well as from PBMCs of individuals supplemented with a vitamin D3 bolus. The led to the genes ACVRL1, CAMP, CD14, CD93, CEBPB, FN1, MAPK13, NINJ1, LILRB4, LRRC25, SEMA6B, SRGN, THBD, THEMIS2 and TREM1. Public epigenome- and transcriptome-wide data from THP-1 cells were used to characterize these genes based on the level of their VDR-driven enhancers as well as the level of the dynamics of their mRNA production. Both types of datasets allowed the categorization of the vitamin D target genes into three groups according to their role in (i) acute response to infection, (ii) infection in general and (iii) autoimmunity. In conclusion, 15 genes were identified as major mediators of the action of vitamin D in innate and adaptive immunity and their individual functions are explained based on different gene regulatory scenarios.


Blood ◽  
2000 ◽  
Vol 95 (3) ◽  
pp. 879-885 ◽  
Author(s):  
Anastasia Guerriero ◽  
Peter B. Langmuir ◽  
Lisa M. Spain ◽  
Edward W. Scott

The ets-family transcription factor PU.1 is required for the proper development of both myeloid and lymphoid progenitors. We used PU.1-deficient animals to examine the role of PU.1 during dendritic cell development. PU.1−/−animals produce lymphoid-derived dendritic cells (DC): low-density class II major histocompatibility complex [MHC-II+] CD11c+ CD8+DEC-205+. But they lack myeloid-derived DC: low-density MHC-II+ CD11c+ CD8−DEC-205−. PU.1−/− embryos also lack progenitors capable of differentiating into myeloid DC in response to granulocyte-macrophage colony-stimulating factor plus interleukin-4. The appearance of lymphoid DC in developing PU.1−/−thymus was initially delayed, but this population recovered to wild type (WT) levels upon organ culture of isolated thymic lobes. PU.1−/−lymphoid DC were functionally equivalent to WT DC for stimulating T-cell proliferation in mixed lymphocyte reactions. These results demonstrate that PU.1 is required for the development of myeloid DC but not lymphoid DC.


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