The two major lineages of classical dendritic cells (cDCs) express and require either IRF8 or IRF4 transcription factors for their development and function. IRF8-dependent cDCs promote anti-viral and ...T-helper 1 (Th1) cell responses, whereas IRF4-expressing cDCs have been implicated in controlling both Th2 and Th17 cell responses. Here, we have provided evidence that Kruppel-like factor 4 (Klf4) is required in IRF4-expressing cDCs to promote Th2, but not Th17, cell responses in vivo. Conditional Klf4 deletion within cDCs impaired Th2 cell responses during Schistosoma mansoni infection, Schistosoma egg antigen (SEA) immunization, and house dust mite (HDM) challenge without affecting cytotoxic T lymphocyte (CTL), Th1 cell, or Th17 cell responses to herpes simplex virus, Toxoplasma gondii, and Citrobacter rodentium infections. Further, Klf4 deletion reduced IRF4 expression in pre-cDCs and resulted in selective loss of IRF4-expressing cDCs subsets in several tissues. These results indicate that Klf4 guides a transcriptional program promoting IRF4-expressing cDCs heterogeneity.
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•Klf4 is required for the development of a subset of IRF4-expressing cDCs•Klf4 deletion results in reduced pre-cDCs•A specific Klf4-dependent subset can be identified in several tissues•Klf4fl/flItgax-cre mice have selectively impaired Th2 cell immunity
The IRF4-expressing cDCs subset is highly heterogeneous and has been implicated in priming Th17, as well as Th2 cell immunity. Murphy and colleagues dissect this heterogeneity showing a developmental requirement for Klf4 on specific subsets across several tissues. Moreover, Klf4 guides a transcriptional program necessary for Th2 cell immunity.
The dendritic cells (DCs) of the immune system function in innate and adaptive responses by directing activity of various effector cells rather than serving as effectors themselves. DCs and closely ...related myeloid lineages share expression of many surface receptors, presenting a challenge in distinguishing their unique in vivo functions. Recent work has taken advantage of unique transcriptional programs to identify and manipulate murine DCs in vivo. This work has assigned several nonredundant in vivo functions to distinct DC lineages, consisting of plasmacytoid DCs and several subsets of classical DCs that promote different immune effector modules in response to pathogens. In parallel, a correspondence between human and murine DC subsets has emerged, underlying structural similarities for the DC lineages between these species. Recent work has begun to unravel the transcriptional circuitry that controls the development and diversification of DCs from common progenitors in the bone marrow.
Both classical DCs (cDCs) and monocyte-derived DCs (Mo-DCs) are capable of cross-priming CD8+ T cells in response to cell-associated antigens. We found that Ly-6ChiTREML4− monocytes can differentiate ...into Zbtb46+ Mo-DCs in response to granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) but that Ly-6ChiTREML4+ monocytes were committed to differentiate into Ly-6CloTREML4+ monocytes. Differentiation of Zbtb46+ Mo-DCs capable of efficient cross-priming required both GM-CSF and IL-4 and was accompanied by the induction of Batf3 and Irf4. However, monocytes require IRF4, but not BATF3, to differentiate into Zbtb46+ Mo-DCs capable of cross-priming CD8+ T cells. Instead, Irf4−/− monocytes differentiate into macrophages in response to GM-CSF and IL-4. Thus, cDCs and Mo-DCs require distinct transcriptional programs of differentiation in acquiring the capacity to prime CD8+ T cells. These differences may be of consideration in the use of therapeutic DC vaccines based on Mo-DCs.
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•GM-CSF-derived Mo-DCs require IL-4 to cross-present cell-associated antigen•Monocytes expressing TremL4 lose potential to differentiate into DCs•Monocytes require IRF4, but not Batf3, to become APCs that can prime CD8+ T cells
The transcriptional programs required for differentiation of cross-priming APCs from various lineages are unknown. Briseño et al. show that Mo-DCs use a program distinct from that of cDCs, requiring IRF4 but not Batf3. These differences may impact the design of vaccines based on Mo-DCs that would require efficient cross-priming of T cells.
Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor SPI-C is selectively expressed by RPM and is required for their ...development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM1+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor BACH1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Furthermore, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insights into iron homeostasis.
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•Spic regulates the development of RPM and BMM•Heme induces Spic expression in monocytes and macrophages•Bach1 is a transcriptional repressor of Spic•Heme-mediated degradation of BACH1 induces Spic expression
Heme acts as a metabolite to induce the expression of the transcription factor SPI-C in circulating monocytes, which in turn drives their differentiation into specialized macrophages in the spleen and bone marrow.
The impact of coronavirus disease 2019 on pregnant women is incompletely understood, but early data from case series suggest a variable course of illness from asymptomatic or mild disease to maternal ...death. It is unclear whether pregnant women manifest enhanced disease similar to influenza viral infection or whether specific risk factors might predispose to severe disease.
To describe maternal disease and obstetrical outcomes associated with coronavirus disease 2019 in pregnancy to rapidly inform clinical care.
This is a retrospective study of pregnant patients with a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection from 6 hospital systems in Washington State between Jan. 21, 2020, and April 17, 2020. Demographics, medical and obstetrical history, and coronavirus disease 2019 encounter data were abstracted from medical records.
A total of 46 pregnant patients with a severe acute respiratory syndrome coronavirus 2 infection were identified from hospital systems capturing 40% of births in Washington State. Nearly all pregnant individuals with a severe acute respiratory syndrome coronavirus 2 infection were symptomatic (93.5%, n=43) and the majority were in their second or third trimester (43.5% n=20 and 50.0% n=23, respectively). Symptoms resolved in a median of 24 days (interquartile range, 13–37). Notably, 7 women were hospitalized (16%) including 1 admitted to the intensive care unit. A total of 6 cases (15%) were categorized as severe coronavirus disease 2019 with nearly all patients being either overweight or obese before pregnancy or with asthma or other comorbidities. Of the 8 deliveries that occurred during the study period, there was 1 preterm birth at 33 weeks’ gestation to improve pulmonary status in a woman with class III obesity, and 1 stillbirth of unknown etiology.
Severe coronavirus disease 2019 developed in approximately 15% of pregnant patients and occurred primarily in overweight or obese women with underlying conditions. Obesity and coronavirus disease 2019 may synergistically increase risk for a medically indicated preterm birth to improve maternal pulmonary status in late pregnancy. These findings support categorizing pregnant patients as a higher-risk group, particularly those with chronic comorbidities.
Evidence is accumulating that coronavirus disease 2019 increases the risk of hospitalization and mechanical ventilation in pregnant patients and for preterm delivery. However, the impact on maternal ...mortality and whether morbidity is differentially affected by disease severity at delivery and trimester of infection are unknown.
This study aimed to describe disease severity and outcomes of severe acute respiratory syndrome coronavirus 2 infections in pregnancy across the Washington State, including pregnancy complications and outcomes, hospitalization, and case fatality.
Pregnant patients with a polymerase chain reaction–confirmed severe acute respiratory syndrome coronavirus 2 infection between March 1, 2020, and June 30, 2020, were identified in a multicenter retrospective cohort study from 35 sites in Washington State. Sites captured 61% of annual state deliveries. Case-fatality rates in pregnancy were compared with coronavirus disease 2019 fatality rates in similarly aged adults in Washington State using rate ratios and rate differences. Maternal and neonatal outcomes were compared by trimester of infection and disease severity at the time of delivery.
The principal study findings were as follows: (1) among 240 pregnant patients in Washington State with severe acute respiratory syndrome coronavirus 2 infections, 1 in 11 developed severe or critical disease, 1 in 10 were hospitalized for coronavirus disease 2019, and 1 in 80 died; (2) the coronavirus disease 2019–associated hospitalization rate was 3.5-fold higher than in similarly aged adults in Washington State (10.0% vs 2.8%; rate ratio, 3.5; 95% confidence interval, 2.3–5.3); (3) pregnant patients hospitalized for a respiratory concern were more likely to have a comorbidity or underlying conditions including asthma, hypertension, type 2 diabetes mellitus, autoimmune disease, and class III obesity; (4) 3 maternal deaths (1.3%) were attributed to coronavirus disease 2019 for a maternal mortality rate of 1250 of 100,000 pregnancies (95% confidence interval, 257–3653); (5) the coronavirus disease 2019 case fatality in pregnancy was a significant 13.6-fold (95% confidence interval, 2.7–43.6) higher in pregnant patients than in similarly aged individuals in Washington State with an absolute difference in mortality rate of 1.2% (95% confidence interval, −0.3 to 2.6); and (6) preterm birth was significantly higher among women with severe or critical coronavirus disease 2019 at delivery than for women who had recovered from coronavirus disease 2019 (45.4% severe or critical coronavirus disease 2019 vs 5.2% mild coronavirus disease 2019; P<.001).
Coronavirus disease 2019 hospitalization and case-fatality rates in pregnant patients were significantly higher than in similarly aged adults in Washington State. These data indicate that pregnant patients are at risk of severe or critical disease and mortality compared to nonpregnant adults, and also at risk for preterm birth.
The transcription factors Batf3 and IRF8 are required for the development of CD8α(+) conventional dendritic cells (cDCs), but the basis for their actions has remained unclear. Here we identified two ...progenitor cells positive for the transcription factor Zbtb46 that separately generated CD8α(+) cDCs and CD4(+) cDCs and arose directly from the common DC progenitor (CDP). Irf8 expression in CDPs required prior autoactivation of Irf8 that was dependent on the transcription factor PU.1. Specification of the clonogenic progenitor of CD8α(+) cDCs (the pre-CD8 DC) required IRF8 but not Batf3. However, after specification of pre-CD8 DCs, autoactivation of Irf8 became Batf3 dependent at a CD8α(+) cDC-specific enhancer with multiple transcription factor AP1-IRF composite elements (AICEs) within the Irf8 superenhancer. CDPs from Batf3(-/-) mice that were specified toward development into pre-CD8 DCs failed to complete their development into CD8α(+) cDCs due to decay of Irf8 autoactivation and diverted to the CD4(+) cDC lineage.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Distinguishing dendritic cells (DCs) from other cells of the mononuclear phagocyte system is complicated by the shared expression of cell surface markers such as CD11c. In this study, we identified ...Zbtb46 (BTBD4) as a transcription factor selectively expressed by classical DCs (cDCs) and their committed progenitors but not by plasmacytoid DCs (pDCs), monocytes, macrophages, or other lymphoid or myeloid lineages. Using homologous recombination, we replaced the first coding exon of Zbtb46 with GFP to inactivate the locus while allowing detection of Zbtb46 expression. GFP expression in Zbtb46(gfp/+) mice recapitulated the cDC-specific expression of the native locus, being restricted to cDC precursors (pre-cDCs) and lymphoid organ- and tissue-resident cDCs. GFP(+) pre-cDCs had restricted developmental potential, generating cDCs but not pDCs, monocytes, or macrophages. Outside the immune system, Zbtb46 was expressed in committed erythroid progenitors and endothelial cell populations. Zbtb46 overexpression in bone marrow progenitor cells inhibited granulocyte potential and promoted cDC development, and although cDCs developed in Zbtb46(gfp/gfp) (Zbtb46 deficient) mice, they maintained expression of granulocyte colony-stimulating factor and leukemia inhibitory factor receptors, which are normally down-regulated in cDCs. Thus, Zbtb46 may help enforce cDC identity by restricting responsiveness to non-DC growth factors and may serve as a useful marker to identify rare cDC progenitors and distinguish between cDCs and other mononuclear phagocyte lineages.
Dendritic cells (DCs) are thought to form a dendritic network across barrier surfaces and throughout organs, including the kidney, to perform an important sentinel function. However, previous studies ...of DC function used markers, such as CD11c or CX3CR1, that are not unique to DCs. Here, we evaluated the role of DCs in renal inflammation using a CD11c reporter mouse line and two mouse lines with DC-specific reporters,
-GFP and
-GFP. Multiphoton microscopy of kidney sections confirmed that most of the dendritically shaped CD11c
cells forming a network throughout the renal interstitium expressed macrophage-specific markers. In contrast, DCs marked by
-GFP or
-GFP were less abundant, concentrated around blood vessels, and round in shape. We confirmed this pattern of localization using imaging mass cytometry. Motility measurements showed that resident macrophages were sessile, whereas DCs were motile before and after inflammation. Although uninflamed glomeruli rarely contained DCs, injury with nephrotoxic antibodies resulted in accumulation of ZBTB46
cells in the periglomerular region. ZBTB46 identifies all classic DCs, which can be categorized into two functional subsets that express either CD103 or CD11b. Depletion of ZBTB46
cells attenuated the antibody-induced kidney injury, whereas deficiency of the CD103
subset accelerated injury through a mechanism that involved increased neutrophil infiltration. RNA sequencing 7 days after nephrotoxic antibody injection showed that CD11b
DCs expressed the neutrophil-attracting cytokine CXCL2, whereas CD103
DCs expressed high levels of several anti-inflammatory genes. These results provide new insights into the distinct functions of the two major DC subsets in glomerular inflammation.
Dendritic cells (DCs) and monocytes develop from a series of bone-marrow–resident progenitors in which lineage potential is regulated by distinct transcription factors. Zeb2 is an E-box–binding ...protein associated with epithelial–mesenchymal transition and is widely expressed among hematopoietic lineages. Previously, we observed that Zeb2 expression is differentially regulated in progenitors committed to classical DC (cDC) subsets in vivo. Using systems for inducible gene deletion, we uncover a requirement for Zeb2 in the development of Ly-6Chi monocytes but not neutrophils, and we show a corresponding requirement for Zeb2 in expression of the M-CSF receptor in the bone marrow. In addition, we confirm a requirement for Zeb2 in development of plasmacytoid DCs but find that Zeb2 is not required for cDC2 development. Instead, Zeb2 may act to repress cDC1 progenitor specification in the context of inflammatory signals.
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