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1.
Arthritis Rheumatol ; 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32293098

RESUMO

Poor outcomes in COVID-19 correlate with clinical and laboratory features of cytokine storm syndrome. Broad screening for cytokine storm and early, targeted antiinflammatory therapy may prevent immunopathology and could help conserve limited health care resources. While studies are ongoing, extrapolating from clinical experience in cytokine storm syndromes may benefit the multidisciplinary teams caring for patients with severe COVID-19.

2.
Immunohorizons ; 4(3): 119-128, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144186

RESUMO

The RAG1 and RAG2 proteins are essential for the assembly of Ag receptor genes in the process known as VDJ recombination, allowing for an immense diversity of lymphocyte Ag receptors. Congruent with their importance, RAG1 and RAG2 have been a focus of intense study for decades. To date, RAG1 has been studied as a single isoform; however, our identification of a spontaneous nonsense mutation in the 5' region of the mouse Rag1 gene lead us to discover N-truncated RAG1 isoforms made from internal translation initiation. Mice homozygous for the RAG1 nonsense mutation only express N-truncated RAG1 isoforms and have defects in Ag receptor rearrangement similar to human Omenn syndrome patients with truncating 5' RAG1 frameshift mutations. We show that the N-truncated RAG1 isoforms are derived from internal translation initiation start sites. Given the seemingly inactivating Rag1 mutation, it is striking that homozygous mutant mice do not have the expected SCID. We propose that evolution has garnered RAG1 and other important genes with the ability to form truncated proteins via internal translation to minimize the deleterious effects of 5' nonsense mutations. This mechanism of internal translation initiation is particularly important to consider when interpreting nonsense or frameshift mutations in whole-genome sequencing, as such mutations may not lead to loss of protein.

3.
Arthritis Rheumatol ; 72(2): 335-347, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31400073

RESUMO

OBJECTIVE: Familial hemophagocytic lymphohistiocytosis (FHLH) is a complex cytokine storm syndrome caused by genetic abnormalities rendering CD8+ T cells and natural killer cells incapable of cytolytic killing. In murine models of FHLH, interferon-γ (IFNγ) produced by CD8+ T cells has been identified as a critical mediator of disease, and an IFNγ-blocking antibody (emapalumab) has recently been approved by the Food and Drug Administration. However, development of hemophagocytic lymphohistiocytosis (HLH)/macrophage activation syndrome (MAS) in patients who are genetically unresponsive to IFNγ questions the absolute necessity of IFNγ in driving disease. This study was undertaken to determine the necessity of IFNγ in driving HLH. METHODS: IFNγ-/- Prf1-/- mice were infected with lymphocytic choriomeningitis virus (LCMV), and HLH immunopathologic features, including survival, weight loss, cytopenias, cytokine profiles, and immune cell phenotypes, were assessed. Mixed bone marrow chimeras were created to determine the immune cell-intrinsic role of IFNγ receptor signaling. CD8+ T cell depletion and interleukin-33 (IL-33)/ST2 blockade were performed using monoclonal antibodies. RESULTS: LCMV infection of IFNγ-/- Prf1-/- mice resulted in severe HLH-like disease. CD8+ T cells and the IL-33/ST2 axis remained essential mediators of disease; however, IFNγ-independent HLH immunopathology correlated with a 10-15-fold increase in neutrophilia (P < 0.001) and an altered cytokine milieu dominated by IL-6, IL-1ß, and granulocyte-macrophage colony-stimulating factor (GM-CSF) (P < 0.05). Furthermore, IFNγ regulated CD8+ T cell expression of GM-CSF and neutrophil survival. CONCLUSION: IFNγ is not necessary for the development of fulminant HLH, requiring physicians to consider case-by-case treatment strategies. Use of therapies that target upstream activators of CD8+ T cells, such as IL-33/ST2 signaling, may be more universally applicable treatment options that ameliorate both IFNγ-dependent and -independent manifestations of HLH/MAS.

4.
Ann Rheum Dis ; 78(12): 1722-1731, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31562126

RESUMO

OBJECTIVE: To investigate the characteristics and risk factors of a novel parenchymal lung disease (LD), increasingly detected in systemic juvenile idiopathic arthritis (sJIA). METHODS: In a multicentre retrospective study, 61 cases were investigated using physician-reported clinical information and centralised analyses of radiological, pathological and genetic data. RESULTS: LD was associated with distinctive features, including acute erythematous clubbing and a high frequency of anaphylactic reactions to the interleukin (IL)-6 inhibitor, tocilizumab. Serum ferritin elevation and/or significant lymphopaenia preceded LD detection. The most prevalent chest CT pattern was septal thickening, involving the periphery of multiple lobes ± ground-glass opacities. The predominant pathology (23 of 36) was pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia (PAP/ELP), with atypical features including regional involvement and concomitant vascular changes. Apparent severe delayed drug hypersensitivity occurred in some cases. The 5-year survival was 42%. Whole exome sequencing (20 of 61) did not identify a novel monogenic defect or likely causal PAP-related or macrophage activation syndrome (MAS)-related mutations. Trisomy 21 and young sJIA onset increased LD risk. Exposure to IL-1 and IL-6 inhibitors (46 of 61) was associated with multiple LD features. By several indicators, severity of sJIA was comparable in drug-exposed subjects and published sJIA cohorts. MAS at sJIA onset was increased in the drug-exposed, but was not associated with LD features. CONCLUSIONS: A rare, life-threatening lung disease in sJIA is defined by a constellation of unusual clinical characteristics. The pathology, a PAP/ELP variant, suggests macrophage dysfunction. Inhibitor exposure may promote LD, independent of sJIA severity, in a small subset of treated patients. Treatment/prevention strategies are needed.

5.
Mol Cell Biol ; 39(21)2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31427458

RESUMO

Macrophages are professional phagocytes that are essential for host defense and tissue homeostasis. Proper membrane trafficking and degradative functions of the endolysosomal system are known to be critical for the function of these cells. We have found that PIKfyve, the kinase that synthesizes the endosomal phosphoinositide phosphatidylinositol-3,5-bisphosphate, is an essential regulator of lysosomal biogenesis and degradative functions in macrophages. Genetically engineered mice lacking PIKfyve in their myeloid cells (PIKfyvefl/fl LysM-Cre) develop diffuse tissue infiltration of foamy macrophages, hepatosplenomegaly, and systemic inflammation. PIKfyve loss in macrophages causes enlarged endolysosomal compartments and impairs the lysosomal degradative function. Moreover, PIKfyve deficiency increases the cellular levels of lysosomal proteins. Although PIKfyve deficiency reduced the activation of mTORC1 pathway and was associated with increased cleavage of TFEB proteins, this does not translate into transcriptional activation of lysosomal genes, suggesting that PIKfyve modulates the abundance of lysosomal proteins by affecting the degradation of these proteins. Our study shows that PIKfyve modulation of lysosomal degradative activity and protein expression is essential to maintain lysosomal homeostasis in macrophages.


Assuntos
Lisossomos/metabolismo , Macrófagos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Animais , Endossomos/metabolismo , Feminino , Homeostase/fisiologia , Inflamação/metabolismo , Masculino , Camundongos , Camundongos Knockout , Células Mieloides/metabolismo , Fagossomos/metabolismo , Fosfatidilinositol 3-Quinases/deficiência , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilinositóis/metabolismo , Transporte Proteico
6.
JCI Insight ; 4(7)2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30944248

RESUMO

Systemic lupus erythematosus (SLE) is an autoimmune disorder that predominantly affects women and is driven by autoreactive T cell-mediated inflammation. It is known that individuals with multiple X-chromosomes are at increased risk for developing SLE; however, the mechanisms underlying this genetic basis are unclear. Here, we use single cell imaging to determine the epigenetic features of the inactive X (Xi) in developing thymocytes, mature T cell subsets, and T cells from SLE patients and mice. We show that Xist RNA and heterochromatin modifications transiently reappear at the Xi and are missing in mature single positive T cells. Activation of mature T cells restores Xist RNA and heterochromatin marks simultaneously back to the Xi. Notably, X-chromosome inactivation (XCI) maintenance is altered in T cells of SLE patients and late-stage-disease NZB/W F1 female mice, and we show that X-linked genes are abnormally upregulated in SLE patient T cells. SLE T cells also have altered expression of XIST RNA interactome genes, accounting for perturbations of Xi epigenetic features. Thus, abnormal XCI maintenance is a feature of SLE disease, and we propose that Xist RNA localization at the Xi could be an important factor for maintaining dosage compensation of X-linked genes in T cells.

7.
JCI Insight ; 52019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30843872

RESUMO

The mTOR pathway is central to most cells. How mTOR is activated in macrophages and modulates macrophage physiology remain poorly understood. The tumor suppressor Folliculin (FLCN) is a GAP for RagC/D, a regulator of mTOR. We show here that LPS potently suppresses FLCN in macrophages, allowing nuclear translocation of the transcription factor TFE3, leading to lysosome biogenesis, cytokine production, and hypersensitivity to inflammatory signals. Nuclear TFE3 additionally activates a transcriptional RagD positive feedback loop that stimulates FLCN-independent canonical mTOR signaling to S6K and increases cellular proliferation. LPS thus simultaneously suppresses the TFE3 arm and activates the S6K arm of mTOR. In vivo, mice lacking myeloid FLCN reveal chronic macrophage activation, leading to profound histiocytic infiltration and tissue disruption, with hallmarks of human histiocytic syndromes like Erdheim-Chester Disease. Our data thus identify a critical FLCN-mTOR-TFE3 axis in myeloid cells, modulated by LPS, that balances mTOR activation and curbs innate immune responses.

8.
JCI Insight ; 4(1)2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30626747

RESUMO

Host-commensal interactions are critical for the generation of robust inflammatory responses, yet the mechanisms leading to this effect remain poorly understood. Using a murine model of cytokine storm, we identified that host microbiota are required to sustain systemic TLR-driven immune responses. Mice treated with broad-spectrum antibiotics or raised in germ-free conditions responded normally to an initial TLR signal but failed to sustain production of proinflammatory cytokines following administration of repeated TLR signals in vivo. Mechanistically, host microbiota primed JAK signaling in myeloid progenitors to promote TLR-enhanced myelopoiesis, which is required for the accumulation of TLR-responsive monocytes. In the absence of TLR-enhanced monocytopoiesis, antibiotic-treated mice lost their ability to respond to repeated TLR stimuli and were protected from cytokine storm-induced immunopathology. These data reveal priming of TLR-enhanced myelopoiesis as a microbiota-dependent mechanism that regulates systemic inflammatory responses and highlight a role for host commensals in the pathogenesis of cytokine storm syndromes.

9.
Nat Mater ; 18(3): 289-297, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30664693

RESUMO

Initiation of the innate sterile inflammatory response that can develop in response to microparticle exposure is little understood. Here, we report that a potent type 2 immune response associated with the accumulation of neutrophils, eosinophils and alternatively activated (M2) macrophages was observed in response to sterile microparticles similar in size to wear debris associated with prosthetic implants. Although elevations in interleukin-33 (IL-33) and type 2 cytokines occurred independently of caspase-1 inflammasome signalling, the response was dependent on Bruton's tyrosine kinase (BTK). IL-33 was produced by macrophages and BTK-dependent expression of IL-33 by macrophages was sufficient to initiate the type 2 response. Analysis of inflammation in patient periprosthetic tissue also revealed type 2 responses under aseptic conditions in patients undergoing revision surgery. These findings indicate that microparticle-induced sterile inflammation is initiated by macrophages activated to produce IL-33. They further suggest that both BTK and IL-33 may provide therapeutic targets for wear debris-induced periprosthetic inflammation.


Assuntos
Tirosina Quinase da Agamaglobulinemia/metabolismo , Interleucina-33/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Falha de Prótese , Artroplastia/efeitos adversos , Caspase 1/metabolismo , Humanos , Imunidade Inata/efeitos dos fármacos , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Interleucina-33/biossíntese , Macrófagos/imunologia , Transdução de Sinais/efeitos dos fármacos
10.
Arthritis Rheumatol ; 71(1): 161-168, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30073799

RESUMO

OBJECTIVE: Macrophage activation syndrome (MAS) is a life-threatening cytokine storm syndrome that occurs in patients with underlying rheumatic diseases. Preclinical and clinical data suggest that interferon-γ (IFNγ) is pathogenic in MAS, but how IFNγ may be linked to disease pathogenesis remains unknown. This study was undertaken to determine whether IFNγ signals synergize with systemic innate immune responses to drive the cytokine storm in a murine model of MAS. METHODS: IFNγ-deficient mice were treated with 5 doses of the Toll-like receptor 9 (TLR-9) agonist CpG 1826, IFNγ, or a combination of the 2 stimuli over the course of 10 days. Immunopathologic features of MAS, including cytopenias, hepatitis, hepatosplenomegaly, and induction of inflammatory myelopoiesis, were assessed. Mixed bone marrow chimeras were created to determine whether TLR-9- and IFNγ receptor 1 (IFNγR1)-dependent signals induce enhanced myelopoiesis in a cell-intrinsic or cell-extrinsic manner. RESULTS: IFNγ-deficient mice did not develop features of MAS when treated with repeated doses of either the TLR-9 agonist or IFNγ alone. In contrast, IFNγ-deficient mice treated with both the TLR-9 agonist and IFNγ developed cytopenias, hepatitis, and hepatosplenomegaly, reproducing major clinical features of MAS. TLR-9- and IFNγR1-dependent signals synergized to enhance myeloid progenitor cell function and induce myelopoiesis in vivo, which occurred through cell-extrinsic mechanisms and correlated with the induction of disease. CONCLUSION: These findings demonstrate that TLR-9-driven signals potentiate the effects of IFNγ to initiate murine MAS, and provide evidence that induction of inflammatory myelopoiesis is a common TLR-9- and IFNγ-dependent pathway that may contribute to the pathogenesis of MAS.


Assuntos
Interferon gama/imunologia , Síndrome de Ativação Macrofágica/imunologia , Mielopoese/efeitos dos fármacos , Receptor Toll-Like 9/imunologia , Animais , Modelos Animais de Doenças , Citometria de Fluxo , Hepatite/imunologia , Hepatomegalia/imunologia , Interferon gama/farmacologia , Fígado/efeitos dos fármacos , Camundongos , Oligodesoxirribonucleotídeos/farmacologia , Receptores de Interferon/imunologia , Baço/efeitos dos fármacos , Esplenomegalia/imunologia , Receptor Toll-Like 9/agonistas , Quimeras de Transplante
11.
Front Immunol ; 9: 2642, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30515155

RESUMO

Danger signals mediated through ST2, the interleukin-33 (IL-33) receptor, amplify CD8+ T cell-mediated inflammation in the murine model of familial hemophagocytic lymphohistiocytosis type 2 (FHL2), and blockade of ST2 provides a potential therapeutic strategy in this disease. However, the long-term effects of disrupting IL-33/ST2 signaling on the CD8+ T cell compartment are unknown. Here, we examined the evolution of the T cell response in murine FHL type 2 in the absence of ST2 signaling and found that CD8+ T cells gradually undergo exhaustion, similar to a related nonfatal FHL model. ST2 inhibition indirectly promotes CD8+ T cell exhaustion, and in contrast to other forms of FHL, reversal of exhaustion does not affect mortality. Disruption of IL-33 signaling exerts a more significant impact on the CD8+ T cell compartment early in the course of disease by intrinsically limiting CD8+ T cell proliferative and cytokine production capacity. Our data thus suggest that while ST2 blockade ultimately enables the development of CD8+ T cell exhaustion in late-stage murine FHL2, exhaustion is merely an effect, rather than the cause, of extended survival in these mice. The acute impact of ST2 inhibition on both the quantity and quality of the effector CD8+ T cell response more likely underlies the protective benefits of this treatment. This study provides evidence that redefines the relationship between CD8+ T cell exhaustion and mortality in murine FHL and supports the therapeutic use of ST2 blockade during the acute stage of disease.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Interleucina-33/imunologia , Linfo-Histiocitose Hemofagocítica/imunologia , Transdução de Sinais/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Modelos Animais de Doenças , Proteína 1 Semelhante a Receptor de Interleucina-1/genética , Proteína 1 Semelhante a Receptor de Interleucina-1/imunologia , Interleucina-33/genética , Linfo-Histiocitose Hemofagocítica/genética , Linfo-Histiocitose Hemofagocítica/patologia , Camundongos , Camundongos Knockout , Transdução de Sinais/genética
12.
PLoS One ; 13(7): e0200913, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30024926

RESUMO

Toll like receptors (TLRs) share a conserved structure comprising the N-terminal ectodomain, a transmembrane segment and a C-terminal cytoplasmic Toll/IL-1 receptor (TIR) domain. Proper assembly of the TIR domain is crucial for signal transduction; however, the contribution of individual motifs within the TIR domain to TLR trafficking and signaling remains unclear. We targeted a highly conserved tyrosine (Y870) located in the box 1 region of the TIR domain of most TLRs, including TLR9, previously described to be a critical site of phosphorylation in TLR4. We reconstituted bone marrow-derived dendritic cells (BMDC) from Tlr9-/- mice WT TLR9 or Y870F or Y870A mutants. Despite normal interactions with the luminal chaperones GRP94 and UNC93B1, Y870F conferred only partial responsiveness to CpG, and Y870A had no activity and functioned as a dominant negative inhibitor when coexpressed with endogenous TLR9. This loss of function correlated with reduction or absence, respectively, of the 80 kDa mature form of TLR9. In Y870F-expressing cells, CpG-dependent signaling correlated directly with levels of the mature form, suggesting that signaling did not require tyrosine phosphorylation but rather that the Y870F mutation conferred reduced receptor levels due to defective processing or trafficking. Microscopy revealed targeting of the mutant protein to an autophagolysosome-like structure for likely degradation. Collectively we postulate that the conserved Y870 in the TIR domain does not participate in phosphorylation-induced signaling downstream of ligand recognition, but rather is crucial for proper TIR assembly and ER egress, resulting in maturation-specific stabilization of TLR9 within endolysosomes and subsequent pro-inflammatory signaling.


Assuntos
Citocinas/metabolismo , Mutação , Receptor Toll-Like 9/química , Receptor Toll-Like 9/metabolismo , Tirosina/química , Animais , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutagênese Sítio-Dirigida , Fosforilação , Estabilidade Proteica , Transdução de Sinais , Receptor Toll-Like 9/genética , Tirosina/genética
13.
Immunohorizons ; 2(2): 67-73, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29795796

RESUMO

Familial hemophagocytic lymphohistiocytosis 2 (FHL2) is a cytokine storm syndrome characterized by immune hyperactivation with viral infection due to a CD8 T cell cytotoxic killing defect secondary to a perforin deficiency. As most studies of FHL2 mice have used pathogen naïve animals, the effects of immune memory on FHL2 are understudied. We utilized an immunization model of the perforin-deficient mouse to study the effects of immune memory on FHL2. Prior CD8 T cell specific antigen exposure leads to enhanced HLH disease with increased morbidity and decreased time to mortality. Enhanced disease is associated with altered cytokine production and T cell proliferation. Response to IFNγ blockade is reduced and TNFα gains a pathogenic role, while blockade of the IL-33 receptor ST2 remains effective. These results suggest that pre-existing immune memory may worsen outcome and alter treatment response for FHL2 patients who may not be naïve to their immune triggers.

14.
Proc Natl Acad Sci U S A ; 115(18): 4696-4701, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29666241

RESUMO

The nervous system of the bowel regulates the inflammatory phenotype of tissue resident muscularis macrophages (MM), and in adult mice, enteric neurons are the main local source of colony stimulating factor 1 (CSF1), a protein required for MM survival. Surprisingly, we find that during development MM colonize the bowel before enteric neurons. This calls into question the requirement for neuron-derived CSF1 for MM colonization of the bowel. To determine if intestinal innervation is required for MM development, we analyzed MM of neonatal Ret-/- (Ret KO) mice that have no enteric nervous system in small bowel or colon. We found normal numbers of well-patterned MM in Ret KO bowel. Similarly, the abundance and distribution of MM in aganglionic human colon obtained from Hirschsprung disease patients was normal. We also identify endothelial cells and interstitial cells of Cajal as the main sources of CSF1 in the developing bowel. Additionally, MM from neonatal Ret KOs do not differ from controls in baseline activation status or cytokine-production in response to lipopolysaccharide. Unexpectedly, these data demonstrate that the enteric nervous system is dispensable for MM colonization and patterning in the bowel, and suggest that modulatory interactions between MM and the bowel nervous system are established postnatally.


Assuntos
Comunicação Celular/fisiologia , Sistema Nervoso Entérico/embriologia , Feto/embriologia , Intestinos , Fator Estimulador de Colônias de Macrófagos/metabolismo , Macrófagos/metabolismo , Neurônios/metabolismo , Animais , Sistema Nervoso Entérico/citologia , Feto/citologia , Intestinos/citologia , Intestinos/embriologia , Intestinos/inervação , Macrófagos/citologia , Camundongos , Camundongos Knockout , Neurônios/citologia
15.
Hepatology ; 68(3): 1087-1100, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29603342

RESUMO

The cause of pediatric acute liver failure (PALF) is unknown in up to 40% of cases. Evidence suggests that aberrant immune system activation may play a role. We hypothesized that indeterminate PALF cases would exhibit a unique pattern of hepatic inflammation. This was a retrospective and prospective study of PALF cases due to indeterminate (iPALF), autoimmune hepatitis, or known diagnosis (dPALF) etiology. Liver tissue sections were stained with immunohistochemical markers for cytotoxic T-cells (cluster of differentiation 8 [CD8]), perforin, and tissue resident memory T-cells (CD103) and scored as minimal, moderate, or dense. Lymphocytes were isolated from liver tissue for T-cell receptor beta sequencing and flow-cytometric studies. Thirty-three iPALF, 9 autoimmune hepatitis, and 14 dPALF cases were included. Dense hepatic infiltrates of CD8+ T-cells were found in 27 (82%) iPALF cases compared to 1 (7%) dPALF case (P < 0.0001). Perforin staining was dense or moderate in 19 (73%) of 26 iPALF cases compared to minimal in all 7 dPALF cases (P = 0.004); 16 (62%) of 26 iPALF cases had dense CD103 staining compared to none of the 6 dPALF cases (P = 0.001). T-cell receptor beta sequencing of iPALF cases demonstrated increased clonality compared to dPALF and control cases. Flow cytometry and immunohistochemistry revealed that iPALF intrahepatic leukocytes were predominantly tissue resident memory CD8+ T-cells. CONCLUSION: Indeterminate PALF is characterized by a dense CD8+ T-cell hepatic infiltrate consistent with expansion of a tissue resident memory T-cell phenotype; CD8+ T-cells are a biomarker of immune dysregulation in iPALF and may be used to better identify and define this group. (Hepatology 2018).


Assuntos
Antígenos CD/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Cadeias alfa de Integrinas/metabolismo , Falência Hepática Aguda/imunologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Memória Imunológica , Lactente , Masculino , Estudos Prospectivos , Estudos Retrospectivos
16.
Bone ; 109: 201-209, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29288875

RESUMO

Clinical and laboratory observations strongly suggest that the innate immune system induces flare-ups in the setting of dysregulated bone morphogenetic protein (BMP) signaling in fibrodysplasia ossificans progressiva (FOP). In order to investigate the signaling substrates of this hypothesis, we examined toll-like receptor (TLR) activation and bone morphogenetic protein (BMP) signaling in connective tissue progenitor cells (CTPCs) from FOP patients and unaffected individuals. We found that inflammatory stimuli broadly activate TLR expression in FOP CTPCs and that TLR3/TLR4 signaling amplifies BMP pathway signaling through both ligand dependent and independent mechanisms. Importantly, Evolutionarily Conserved Signaling Intermediate in the Toll Pathway (ECSIT) integrates TLR injury signaling with dysregulated BMP pathway signaling in FOP CTPCs. These findings provide novel insight into the cell autonomous integration of injury signals from the innate immune system with dysregulated response signals from the BMP signaling pathway and provide new exploratory targets for therapeutic approaches to blocking the induction and amplification of FOP lesions.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Células do Tecido Conjuntivo/citologia , Células do Tecido Conjuntivo/metabolismo , Miosite Ossificante/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Receptores de Ativinas Tipo I/metabolismo , Western Blotting , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Humanos , Miosite Ossificante/genética , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Receptor 3 Toll-Like/metabolismo
17.
Curr Treatm Opt Rheumatol ; 3(1): 33-48, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28944163

RESUMO

Cytokine storm syndromes require rapid diagnosis and treatment to limit the morbidity and mortality caused by the hyperinflammatory state that characterizes these devastating conditions. Herein, we discuss the current knowledge that guides our therapeutic decision-making and personalization of treatment for patients with cytokine storm syndromes. Firstly, ICU-level supportive care is often required to stabilize patients with fulminant disease while additional diagnostic evaluations proceed to determine the underlying cause of cytokine storm. Pharmacologic interventions should be focused on removing the inciting trigger of inflammation and initiation of an individualized immunosuppressive regimen when immune activation is central to the underlying disease pathophysiology. Monitoring for a clinical response is required to ensure that changes in the therapeutic regimen can be made as clinically warranted. Escalation of immunosuppression may be required if patients respond poorly to the initial therapeutic interventions, while a slow wean of immunosuppression in patients who improve can limit medication-related toxicities. In certain scenarios, a decision must be made whether an individual patient requires hematopoietic cell transplantation to prevent recurrence of disease. Despite these interventions, significant morbidity and mortality remains for cytokine storm patients. Therefore, we use this review to propose a clinical schema to guide current and future attempts to design rational therapeutic interventions for patients suffering from these devastating conditions, which we believe speeds the diagnosis of disease, limits medication-related toxicities, and improves clinical outcomes by targeting the heterogeneous and dynamic mechanisms driving disease in each individual patient.

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