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1.
Cell Res ; 2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34518654

RESUMO

Intestinal stem cell (ISC) differentiation is regulated precisely by a niche in the crypt, where lymphocytes may interact with stem and transient amplifying (TA) cells. However, whether and how lymphocyte-stem/TA cell contact affects ISC differentiation is largely unknown. Here, we uncover a novel role of T cell-stem/TA cell contact in ISC fate decisions. We show that intestinal lymphocyte depletion results in skewed ISC differentiation in mice, which can be rescued by T cell transfer. Mechanistically, integrin αEß7 expressed on T cells binds to E-cadherin on ISCs and TA cells, triggering E-cadherin endocytosis and the consequent Wnt and Notch signaling alterations. Blocking αEß7-E-cadherin adhesion suppresses Wnt signaling and promotes Notch signaling in ISCs and TA cells, leading to defective ISC differentiation. Thus, αEß7+ T cells regulate ISC differentiation at single-cell level through cell-cell contact-mediated αEß7-E-cadherin adhesion signaling, highlighting a critical role of the T cell-stem/TA cell contact in maintaining intestinal homeostasis.

2.
Adv Sci (Weinh) ; 8(17): e2004850, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34240584

RESUMO

Elevated Wnt/ß-catenin signaling has been commonly associated with tumorigenesis especially colorectal cancer (CRC). Here, an MST4-pß-cateninThr40 signaling axis essential for intestinal stem cell (ISC) homeostasis and CRC development is uncovered. In response to Wnt3a stimulation, the kinase MST4 directly phosphorylates ß-catenin at Thr40 to block its Ser33 phosphorylation by GSK3ß. Thus, MST4 mediates an active process that prevents ß-catenin from binding to and being degraded by ß-TrCP, leading to accumulation and full activation of ß-catenin. Depletion of MST4 causes loss of ISCs and inhibits CRC growth. Mice bearing either MST4T178E mutation with constitutive kinase activity or ß-cateninT40D mutation mimicking MST4-mediated phosphorylation show overly increased ISCs/CSCs and exacerbates CRC. Furthermore, the MST4-pß-cateninThr40 axis is upregulated and correlated with poor prognosis of human CRC. Collectively, this work establishes a previously undefined machinery for ß-catenin activation, and further reveals its function in stem cell and tumor biology, opening new opportunities for targeted therapy of CRC.

3.
Front Pharmacol ; 12: 667361, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34177581

RESUMO

Background: Niemann-Pick disease type C1 (NP-C1) is a rare, autosomal-recessive neurodegenerative disorder with no United States Food and Drug Administration (FDA)-approved drug. Lithium has been shown to have considerable neuroprotective effects for neurological disorders such as bipolar disorder, Alzheimer's disease and stroke and has been tested in many clinical trials. However, the pharmacological effect of lithium on NP-C1 neurodegenerative processes has not been investigated. The aim of this study was to provide an initial evaluation of the safety and feasibility of lithium carbonate in patients with NP-C1. Methods: A total of 13 patients diagnosed with NP-C1 who met the inclusion criteria received lithium orally at doses of 300, 600, 900, or 1,200 mg daily. The dose was reduced based on tolerance or safety observations. Plasma 7-ketocholesterol (7-KC), an emerging biomarker of NP-C1, was the primary endpoint. Secondary endpoints included NPC Neurological Severity Scores (NNSS) and safety. Results: Of the 13 patients with NP-C1 (12-33 years) enrolled, three withdrew (discontinuation of follow-up outpatient visits). The last observed post-treatment values of 7-KC concentrations (128 ng/ml, SEM 20) were significantly lower than pretreatment baselines values (185 ng/ml, SEM 29; p = 0.001). The mean NNSS was improved after lithium treatment at 12 months (p = 0.005). Improvement in swallowing capacity was observed in treated patients (p = 0.014). No serious adverse events were recorded in the patients receiving lithium. Conclusion: Lithium is a potential therapeutic option for NP-C1 patients. Larger randomized and double-blind clinical trials are needed to further support this finding. Clinical Trial Registration: ClinicalTrials.gov, NCT03201627.

4.
iScience ; 24(5): 102411, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-33997693

RESUMO

Enhanced stemness in colorectal cancer has been reported and it contributes to aggressive progression, but the underlying mechanisms remain unclear. Here we report a Wnt ligand, Dickkopf-2 (DKK2) is essential for developing colorectal cancer stemness. Genetic depletion of DKK2 in intestinal epithelial or stem cells reduced tumorigenesis and expression of the stem cell marker genes including LGR5 in a model of colitis-associated cancer. Sequential mutations in APC, KRAS, TP53, and SMAD4 genes in colonic organoids revealed a significant increase of DKK2 expression by APC knockout and further increased by additional KRAS and TP53 mutations. Moreover, DKK2 activates proto-oncogene tyrosine-protein kinse Src followed by increased LGR5 expressing cells in colorectal cancer through degradation of HNF4α1 protein. These findings suggest that DKK2 is required for colonic epithelial cells to enhance LGR5 expression during the progression of colorectal cancer.

5.
Sci Transl Med ; 13(591)2021 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-33910977

RESUMO

Acute lung injury (ALI) causes high mortality and lacks any pharmacological intervention. Here, we found that pazopanib ameliorated ALI manifestations and reduced mortality in mouse ALI models and reduced edema in human lung transplantation recipients. Pazopanib inhibits mitogen-activated protein kinase kinase kinase 2 (MAP3K2)- and MAP3K3-mediated phosphorylation of NADPH oxidase 2 subunit p47phox at Ser208 to increase reactive oxygen species (ROS) formation in myeloid cells. Genetic inactivation of MAP3K2 and MAP3K3 in myeloid cells or hematopoietic mutation of p47phox Ser208 to alanine attenuated ALI manifestations and abrogates anti-ALI effects of pazopanib. This myeloid MAP3K2/MAP3K3-p47phox pathway acted via paracrine H2O2 to enhance pulmonary vasculature integrity and promote lung epithelial cell survival and proliferation, leading to increased pulmonary barrier function and resistance to ALI. Thus, pazopanib has the potential to be effective for treating ALI.


Assuntos
Lesão Pulmonar Aguda , Indazóis/farmacologia , MAP Quinase Quinase Quinase 2/antagonistas & inibidores , MAP Quinase Quinase Quinase 3/antagonistas & inibidores , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Lesão Pulmonar Aguda/tratamento farmacológico , Animais , Humanos , Peróxido de Hidrogênio , Camundongos , NADPH Oxidases/metabolismo , Fosforilação , Espécies Reativas de Oxigênio
6.
Cell Res ; 31(6): 631-648, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33782530

RESUMO

RNAi therapy has undergone two stages of development, direct injection of synthetic siRNAs and delivery with artificial vehicles or conjugated ligands; both have not solved the problem of efficient in vivo siRNA delivery. Here, we present a proof-of-principle strategy that reprogrammes host liver with genetic circuits to direct the synthesis and self-assembly of siRNAs into secretory exosomes and facilitate the in vivo delivery of siRNAs through circulating exosomes. By combination of different genetic circuit modules, in vivo assembled siRNAs are systematically distributed to multiple tissues or targeted to specific tissues (e.g., brain), inducing potent target gene silencing in these tissues. The therapeutic value of our strategy is demonstrated by programmed silencing of critical targets associated with various diseases, including EGFR/KRAS in lung cancer, EGFR/TNC in glioblastoma and PTP1B in obesity. Overall, our strategy represents a next generation RNAi therapeutics, which makes RNAi therapy feasible.

7.
Cell Discov ; 6(1): 85, 2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33298864

RESUMO

Collaborator of ARF (CARF) regulates cell proliferative fate through both p53-dependent and -independent mechanisms. Recently, we reported a new function of CARF as a positive regulator of Wnt signaling. Despite these findings, the physiological function of CARF has not been well studied. Here, we generated CARF knockout mice and found that male CARF-/- mice exhibited significantly impaired fertility and Sertoli-cell-only (SCO) syndrome phenotypes. Further studies revealed that loss of CARF in Sertoli cells led to decreased GDNF expression, which hindered spermatogonial stem cells (SSCs) self-renewal. Meanwhile, CARF loss in undifferentiated spermatogonia impaired their proliferation. These two mechanisms together led to SCO syndrome phenotypes, which could be functionally rescued by pharmacological or genetic reactivation of Wnt signaling. Finally, we identified CARFS351F as a potential pathogenic mutation in an SCO patient. Overall, our findings reveal important roles of CARF in spermatogonial self-renewal and proliferation through the Wnt signaling pathway.

8.
Cancer Cell ; 38(6): 844-856.e7, 2020 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-33186520

RESUMO

Ependymoma is the third most common pediatric tumor with posterior fossa group A (PFA) being its most aggressive subtype. Ependymomas are generally refractory to chemotherapies and thus lack any effective treatment. Here, we report that elevated expression of CXorf67 (chromosome X open reading frame 67), which frequently occurs in PFA ependymomas, suppresses homologous recombination (HR)-mediated DNA repair. Mechanistically, CXorf67 interacts with PALB2 and inhibits PALB2-BRCA2 interaction, thereby inhibiting HR repair. Concordantly, tumor cells with high CXorf67 expression levels show increased sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors, especially when combined with radiotherapy. Thus, our findings have revealed a role of CXorf67 in HR repair and suggest that combination of PARP inhibitors with radiotherapy could be an effective treatment option for PFA ependymomas.


Assuntos
Proteína BRCA2/metabolismo , Ependimoma/terapia , Proteína do Grupo de Complementação N da Anemia de Fanconi/metabolismo , Neoplasias Infratentoriais/terapia , Proteínas Oncogênicas/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/administração & dosagem , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Quimiorradioterapia , Ependimoma/genética , Ependimoma/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos da radiação , Humanos , Neoplasias Infratentoriais/genética , Neoplasias Infratentoriais/metabolismo , Camundongos , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Oncogênicas/genética , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Reparo de DNA por Recombinação/efeitos dos fármacos , Reparo de DNA por Recombinação/efeitos da radiação , Regulação para Cima , Ensaios Antitumorais Modelo de Xenoenxerto
9.
Biomed Pharmacother ; 127: 110229, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32559853

RESUMO

There are limited options for targeted therapies for colorectal cancer (CRC). Anti-EGFR therapy is limited to CRC without KRAS mutations. Even worse, most of CRC are refractory to currently immune checkpoint blockade. DKK2, which is upregulated in CRC, was recently found to suppress host immune responses, and its blockage effectively impeded tumor progression in benign genetic CRC models in our previous study. Here, our recent study demonstrated that in human CRC tumor samples expressing high levels of DKK2, DKK2 blockade caused stronger activation of tumor infiltrating CD8+ T cells in ex vivo culture. Intriguingly, we observed a correlation of high DKK2 expression with increased lymph node metastasis prevalence in these CRC patients as well. Furthermore, in a mouse genetic CRC model with mutations in APC and KRAS, which more closely mimics advanced human CRC, we confirmed the tumor inhibitory effect of DKK2 blockade, which significantly retarded tumor progression and extended survival, with increased immune effector cell activation and reduced angiogenesis. Based on this, we performed a combined administration of DKK2 blockade with sub-optimal anti-VEGFR treatment and observed a synergetic effect on suppressing tumor angiogenesis and progression, as well as extending survival, better than those of every single therapy. Thus, this study provides further evidence for the potential therapeutic application of DKK2 blockade in the clinical treatment of human CRC.


Assuntos
Neoplasias Colorretais/imunologia , Imunoterapia/métodos , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos/farmacologia , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/imunologia , Neoplasias Colorretais/genética , Sinergismo Farmacológico , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Camundongos , Pessoa de Meia-Idade , Mutação , Neovascularização Patológica/imunologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Receptores de Fatores de Crescimento do Endotélio Vascular/imunologia
10.
Sci Adv ; 6(22): eaaw5851, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32537485

RESUMO

Several signaling events have been recognized as essential for regulating cell lineage specification and organogenesis in animals. We find that the gain of an amino-terminal caveolin binding motif (CBM) in the α subunit of the Na/K-adenosine triphosphatase (ATPase) (NKA) is required for the early stages of organogenesis in both mice and Caenorhabditis elegans. The evolutionary gain of the CBM occurred at the same time as the acquisition of the binding sites for Na+/K+. Loss of this CBM does not affect cell lineage specification or the initiation of organogenesis, but arrests further organ development. Mechanistically, this CBM is essential for the dynamic operation of Wnt and the timely up-regulation of transcriptional factors during organogenesis. These results indicate that the NKA was evolved as a dual functional protein that works in concert with Wnt as a hitherto unrecognized common mechanism to enable stem cell differentiation and organogenesis in multicellular organisms within the animal kingdom.

11.
Antib Ther ; 3(2): 63-70, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32391516

RESUMO

Dickkopf-related protein 2 (DKK2)is a member of the Dickkopf family in Wnt signaling pathway. Recently, we found that antibodies against DKK2 could activate natural killer (NK) and CD8+ T cells in tumors and inhibit tumor growth. In this paper, we report the rational design of peptides for identification of linear epitopes and generation of neutralizing monoclonal anti-DKK2 antibodies. To break the immune tolerance, we designed and chemically synthesized six peptides corresponding to different regions of DKK2 as immunogens and found five of them could generate mouse polyclonal antibodies that can bind to the active recombinant human DKK2 protein. Neutralizing mouse monoclonal antibodies (5F8 and 1A10) against human DKK2 were successfully developed by immunizing the mice with two different peptides (34KLNSIKSSL42 and 240KVWKDATYS248) conjugated to Keyhole limpet hemocyanin (KLH). The monoclonal antibodies not only abolish DKK2's suppression of Wnt signaling in vitro but also inhibits tumor growth in vivo. Currently, those two mAbs are undergoing humanization as immunotherapy candidates and may offer a new drug for treatment of human cancers.

13.
J Immunol ; 204(4): 1012-1021, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31924649

RESUMO

Cell polarization is a key step for leukocytes adhesion and transmigration during leukocytes' inflammatory infiltration. Polarized localization of plasma membrane (PM) phosphatidylinositol-4-phosphate (PtdIns4P) directs the polarization of RPH3A, which contains a PtdIns4P binding site. Consequently, RPH3A mediates the RAB21 and PIP5K1C90 polarization, which is important for neutrophil adhesion to endothelia during inflammation. However, the mechanism by which RPH3A is recruited only to PM PtdIns4P rather than Golgi PtdIns4P remains unclear. By using ADP-ribosylation factor 6 (ARF6) small interfering RNA, ARF6 dominant-negative mutant ARF6(T27N), and ARF6 activation inhibitor SecinH3, we demonstrate that ARF6 plays an important role in the polarization of RPH3A, RAB21, and PIP5K1C90 in murine neutrophils. PM ARF6 is polarized and colocalized with RPH3A, RAB21, PIP5K1C90, and PM PtdIns4P in mouse and human neutrophils upon integrin stimulation. Additionally, ARF6 binds to RPH3A and enhances the interaction between the PM PtdIns4P and RPH3A. Consistent with functional roles of polarization of RPH3A, Rab21, and PIP5K1C90, ARF6 is also required for neutrophil adhesion on the inflamed endothelial layer. Our study reveals a previously unknown role of ARF6 in neutrophil polarization as being the coincidence-detection code with PM PtdIns4P. Cooperation of ARF6 and PM PtdIns4P direct RPH3A polarization, which is important for neutrophil firm adhesion to endothelia.


Assuntos
Fatores de Ribosilação do ADP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Endotélio/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Ativação de Neutrófilo , Neutrófilos/imunologia , Proteínas de Transporte Vesicular/metabolismo , Animais , Adesão Celular/imunologia , Linhagem Celular , Membrana Celular/metabolismo , Movimento Celular/imunologia , Células Endoteliais , Endotélio/citologia , Endotélio/imunologia , Feminino , Voluntários Saudáveis , Humanos , Camundongos , Neutrófilos/citologia , Neutrófilos/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Cultura Primária de Células
14.
Cell Res ; 29(11): 895-910, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31501519

RESUMO

The response of endothelial cells to signaling stimulation is critical for vascular morphogenesis, homeostasis and function. Vascular endothelial growth factor-a (VEGFA) has been commonly recognized as a pro-angiogenic factor in vertebrate developmental, physiological and pathological conditions for decades. Here we report a novel finding that genetic ablation of CDP-diacylglycerol synthetase-2 (CDS2), a metabolic enzyme that controls phosphoinositide recycling, switches the output of VEGFA signaling from promoting angiogenesis to unexpectedly inducing vessel regression. Live imaging analysis uncovered the presence of reverse migration of the angiogenic endothelium in cds2 mutant zebrafish upon VEGFA stimulation, and endothelium regression also occurred in postnatal retina and implanted tumor models in mice. In tumor models, CDS2 deficiency enhanced the level of tumor-secreted VEGFA, which in-turn trapped tumors into a VEGFA-induced vessel regression situation, leading to suppression of tumor growth. Mechanistically, VEGFA stimulation reduced phosphatidylinositol (4,5)-bisphosphate (PIP2) availability in the absence of CDS2-controlled-phosphoinositide metabolism, subsequently causing phosphatidylinositol (3,4,5)-triphosphate (PIP3) deficiency and FOXO1 activation to trigger regression of CDS2-null endothelium. Thus, our data indicate that the effect of VEGFA on vasculature is context-dependent and can be converted from angiogenesis to vascular regression.


Assuntos
Diacilglicerol Colinofosfotransferase/fisiologia , Neoplasias/irrigação sanguínea , Neovascularização Patológica/genética , Neovascularização Fisiológica/genética , Nucleotidiltransferases/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Animais , Linhagem Celular Tumoral , Diacilglicerol Colinofosfotransferase/genética , Células Endoteliais/enzimologia , Humanos , Melanoma Experimental , Camundongos , Camundongos Knockout , Nucleotidiltransferases/genética , Fator A de Crescimento do Endotélio Vascular/genética , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
15.
Dev Cell ; 49(2): 206-219.e7, 2019 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-30930167

RESUMO

Cell polarization is important for various biological processes. However, its regulation, particularly initiation, is incompletely understood. Here, we investigated mechanisms by which neutrophils break their symmetry and initiate their cytoskeleton polarization from an apolar state in circulation for their extravasation during inflammation. We show here that a local increase in plasma membrane (PM) curvature resulting from cell contact to a surface triggers the initial breakage of the symmetry of an apolar neutrophil and is required for subsequent polarization events induced by chemical stimulation. This local increase in PM curvature recruits SRGAP2 via its F-BAR domain, which in turn activates PI4KA and results in PM PtdIns4P polarization. Polarized PM PtdIns4P is targeted by RPH3A, which directs PIP5K1C90 and subsequent phosphorylated myosin light chain polarization, and this polarization signaling axis regulates neutrophil firm attachment to endothelium. Thus, this study reveals a mechanism for the initiation of cell cytoskeleton polarization.


Assuntos
Polaridade Celular/fisiologia , Neutrófilos/fisiologia , Actinas/metabolismo , Animais , Adesão Celular , Membrana Celular/metabolismo , Membrana Celular/fisiologia , Movimento Celular/fisiologia , Junções Célula-Matriz , Citoesqueleto/metabolismo , Endotélio/metabolismo , Feminino , Proteínas Ativadoras de GTPase/metabolismo , Proteínas Ativadoras de GTPase/fisiologia , Células HEK293 , Humanos , Leucócitos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/metabolismo , Cadeias Leves de Miosina/metabolismo , Neutrófilos/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Fosforilação , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Transdução de Sinais
16.
Nat Commun ; 10(1): 746, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30765691

RESUMO

Excessive or uncontrolled release of proinflammatory cytokines caused by severe viral infections often results in host tissue injury or even death. Phospholipase C (PLC)s degrade phosphatidylinositol-4, 5-bisphosphate (PI(4,5)P2) lipids and regulate multiple cellular events. Here, we report that PLCß2 inhibits the virus-induced expression of pro-inflammatory cytokines by interacting with and inhibiting transforming growth factor-ß-activated kinase 1 (TAK1) activation. Mechanistically, PI(4,5)P2 lipids directly interact with TAK1 at W241 and N245, and promote its activation. Impairing of PI(4,5)P2's binding affinity or mutation of PIP2-binding sites on TAK1 abolish its activation and the subsequent production of pro-inflammatory cytokines. Moreover, PLCß2-deficient mice exhibit increased expression of proinflammatory cytokines and a higher frequency of death in response to virus infection, while the PLCß2 activator, m-3M3FBS, protects mice from severe Coxsackie virus A 16 (CVA16) infection. Thus, our findings suggest that PLCß2 negatively regulates virus-induced pro-inflammatory responses by inhibiting phosphoinositide-mediated activation of TAK1.


Assuntos
Infecções por Coxsackievirus/metabolismo , Citocinas/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfolipase C beta/metabolismo , Animais , Células Cultivadas , Chlorocebus aethiops , Infecções por Coxsackievirus/genética , Infecções por Coxsackievirus/virologia , Citocinas/genética , Enterovirus/fisiologia , Ativação Enzimática , Regulação da Expressão Gênica , Células HEK293 , Humanos , MAP Quinase Quinase Quinases/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfolipase C beta/genética , Ligação Proteica , Células Vero
17.
Immunity ; 50(1): 137-151.e6, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30650373

RESUMO

Fever is an evolutionarily conserved response that confers survival benefits during infection. However, the underlying mechanism remains obscure. Here, we report that fever promoted T lymphocyte trafficking through heat shock protein 90 (Hsp90)-induced α4 integrin activation and signaling in T cells. By inducing selective binding of Hsp90 to α4 integrins, but not ß2 integrins, fever increased α4-integrin-mediated T cell adhesion and transmigration. Mechanistically, Hsp90 bound to the α4 tail and activated α4 integrins via inside-out signaling. Moreover, the N and C termini of one Hsp90 molecule simultaneously bound to two α4 tails, leading to dimerization and clustering of α4 integrins on the cell membrane and subsequent activation of the FAK-RhoA pathway. Abolishment of Hsp90-α4 interaction inhibited fever-induced T cell trafficking to draining lymph nodes and impaired the clearance of bacterial infection. Our findings identify the Hsp90-α4-integrin axis as a thermal sensory pathway that promotes T lymphocyte trafficking and enhances immune surveillance during infection.


Assuntos
Febre/imunologia , Proteínas de Choque Térmico HSP90/metabolismo , Integrina alfa4/metabolismo , Infecções por Salmonella/imunologia , Salmonella typhimurium/imunologia , Linfócitos T/imunologia , Animais , Carga Bacteriana , Adesão Celular , Movimento Celular , Dimerização , Quinase 1 de Adesão Focal/metabolismo , Vigilância Imunológica , Integrina alfa4/genética , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica , Transdução de Sinais , Proteína rhoA de Ligação ao GTP/metabolismo
18.
Cell Rep ; 25(11): 2981-2991.e3, 2018 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-30509557

RESUMO

Haired skin is a defining characteristic of mammals. However, some specialized skin regions, such as human palms, soles and ventral wrist, and mouse plantar foot, are entirely hairless. Using mouse plantar skin as a model system, we show that the endogenous secreted Wnt inhibitor DKK2 suppresses plantar hair follicle development and permits the formation of hairless skin. Plantar skin retains all of the mechanistic components needed for hair follicle development, as genetic deletion of Dkk2 permits formation of fully functional plantar hair follicles that give rise to external hair, contain sebaceous glands and a stem cell compartment, and undergo regenerative growth. In the absence of Dkk2, Wnt/ß-catenin signaling activity is initially broadly elevated in embryonic plantar skin and gradually becomes patterned, mimicking follicular development in normally haired areas. These data provide a paradigm in which regionally restricted expression of a Wnt inhibitor underlies specification of hairless versus hairy skin.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Pele/metabolismo , Animais , Animais Recém-Nascidos , Biomarcadores/metabolismo , Diferenciação Celular , Derme/metabolismo , Derme/ultraestrutura , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário , Folículo Piloso/metabolismo , Folículo Piloso/ultraestrutura , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Camundongos Pelados , Camundongos Endogâmicos C57BL , Coelhos , Pele/ultraestrutura , Células-Tronco/metabolismo , Regulação para Cima , Via de Sinalização Wnt
19.
Nature ; 564(7734): 119-124, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30455424

RESUMO

Haematopoietic stem and progenitor cells (HSPCs) give rise to all blood lineages that support the entire lifespan of vertebrates1. After HSPCs emerge from endothelial cells within the developing dorsal aorta, homing allows the nascent cells to anchor in their niches for further expansion and differentiation2-5. Unique niche microenvironments, composed of various blood vessels as units of microcirculation and other niche components such as stromal cells, regulate this process6-9. However, the detailed architecture of the microenvironment and the mechanism for the regulation of HSPC homing remain unclear. Here, using advanced live imaging and a cell-labelling system, we perform high-resolution analyses of the HSPC homing in caudal haematopoietic tissue of zebrafish (equivalent to the fetal liver in mammals), and reveal the role of the vascular architecture in the regulation of HSPC retention. We identify a VCAM-1+ macrophage-like niche cell population that patrols the inner surface of the venous plexus, interacts with HSPCs in an ITGA4-dependent manner, and directs HSPC retention. These cells, named 'usher cells', together with caudal venous capillaries and plexus, define retention hotspots within the homing microenvironment. Thus, the study provides insights into the mechanism of HSPC homing and reveals the essential role of a VCAM-1+ macrophage population with patrolling behaviour in HSPC retention.


Assuntos
Células Endoteliais/citologia , Células-Tronco Hematopoéticas/citologia , Macrófagos/metabolismo , Nicho de Células-Tronco , Molécula 1 de Adesão de Célula Vascular/metabolismo , Animais , Diferenciação Celular , Movimento Celular , Microambiente Celular , Integrinas/genética , Integrinas/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
20.
Bone Rep ; 9: 154-158, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30364642

RESUMO

Context: Most heritable causes of low bone mass in children occur due to mutations affecting type 1 collagen. We describe two related patients with low bone mass and fracture without mutations in the type 1 collagen genes. Case description: We describe the index case of a 10-year-old girl with low-impact fractures in childhood and her 59-year-old father with traumatic fractures in adulthood, both with low bone mineral density. They were found to have the same heterozygous missense mutation in the WNT1 gene (p.Gly222Arg), occurring in a highly conserved WNT motif in close proximity to the Frizzled binding site. Conclusions: The WNT-ligand WNT1, signaling through the canonical WNT-ß-catenin pathway, plays a critical role in skeletal development, adult skeletal homeostasis, and bone remodeling. Biallelic mutations have been described and are associated with moderate to severe osteogenesis imperfecta, in some cases with extra-skeletal manifestations. Patients with monoallelic mutations, as in our case, seem to present with low bone mineral density and less severe disease. The phenotypic difference between biallelic and monoallelic mutations highlights that the aberrant protein in monoallelic mutations may exert a dominant negative effect on the wild type protein as heterozygous carriers in families with biallelic disease are usually asymptomatic. With better understanding of disorders associated with WNT1 mutations, therapies targeting this signaling pathway may offer therapeutic benefit.

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